vol. 2, no. 1 | january june 2019 sjet | p-issn: 2616-7069 | e-issn: 2617-3115 | vol. 2 | no. 1 | © 2019 sukkur iba 51 effect of tempering temperature on the properties of martensitic stainless steel aisi-420 iftikhar a. channa1, aqeel ahmed shah1, shahid hussain abro1, m. ali siddiqui1, m. mujahid1, ali dad chandio1 abstract: martensitic stainless steels are commercially significant materials owing to the remarkable properties they offer because of their martensitic structure during application. the paper aimed to investigate the effects of tempering temperature on mechanical properties and microstructure. determination of carbide morphology was also included in the study to substantiate the results. this study used aisi 420 samples of 10 mm thickness, hardened at 1050oc and then subjected to tempering treatment at temperatures: 150oc, 250oc, 350oc, 450oc, 550oc and 650oc. each sample was oil quenched after a soaking time of 25 minutes. optical microscopy and scanning electron microscopy was conducted to examine the changes in the microstructure and the morphology of carbides. the results have shown that at various temperatures during tempering there is subsequent increase in toughness where hardness decreases and vice versa. matrix of martensite contains some carbide precipitates. due to temper embrittlement occurring between 350°c-450oc, toughness has been decreased as a result of secondary hardening between the temperatures of 450°c-550°c, hardness has been increased drastically. keywords: martensitic stainless steel aisi 420, tempering, microstructure, temper embrittlement, secondary hardening 1. introduction martensitic stainless steel represents a portion of the 400 series of stainless steels and are essentially fe-cr-c alloys containing 1213% cr. martensitic grades, due to the excellent mechanical properties, high wear resistance and moderate corrosion resistance, are used in various industrial components. 1 department of metallurgical engineering, ned university of engineering and technology, karachi, 75270, pakistan corresponding author: alidad@neduet.edu.pk these wide variations of properties including strength, toughness and hardness values can be achieved through different heat treatments. [1] grade aisi 420 stainless steel possesses good ductility in annealed form notwithstanding the capability of being hardened up to 50 hrc. optimum properties can be achieved with the control of the iftikhar (et.al), effect of tempering temperature on the properties of martensitic stainless steel aisi-420 (pp. 51 56) sukkur iba journal of emerging technologies sjet | volume 2 no. 1 january – june 2019 © sukkur iba university 52 microstructure of these materials by means of austenitizing and tempering heat treatments [2]. an increase in austenitizing temperature results in more dissolution of carbides thus, hardening treatment for this grade includes heating up to 1050°c, followed by quenching in oil or air which gives an optimum percentage of carbide distribution in the matrix resulting in high as-quenched hardness [3]. tempering should be done at 150-370°c in order to get a wide variety of hardness values and mechanical properties. the tempering range of 425-550°c should be avoided [2]. the higher tempering temperatures will cause some precipitation of carbides with an alteration in mechanical properties [1]. in general, over the broad range of tempering temperatures, hardness decreases and toughness increases as the temperature is increased. the prior heat treatment done on the steel has major influence on the final microstructure of aisi 420, which typically comprise of martensite, un-dissolved and/or re-precipitate carbides and retained austenite. the precipitation of carbides in the alloy during tempering is time dependent, which involves precipitation of m3c followed by m7c3 and then m23c6 type alloy carbides [3][4]. the volume fraction and size of the carbide particles present in the steel and the amount of retained austenite play a major role in determining the hardness, strength and toughness of the steel [5]. the martensitic grades are generally are susceptible to surface decarburization during heat treatment, if the furnace atmosphere is not properly controlled. however, with their high chromium content, they are relatively less susceptible than many of the low alloy steels. 2. research objective the present research aims to investigate the behavior of martensitic stainless steel, grade aisi-420, when it is subjected to a range of tempering temperatures. considering the superior properties of stainless steels, it becomes substantial to determine the influence of heat treatment processes on these steels. tempering treatment can have considerable effects on the factors primarily focused in this study, namely: 1) mechanical properties 2) microstructure, and 3) carbide morphology 3. experimental work the chemical composition of the asannealed sample was confirmed by r&d of pakistan steel mills. the composition of the sample is shown in the table 1. as illustrated in figure 1, the samples were subjected to hardening at 1050°c for 25 minutes of soaking time in proportion to the dimensions of the samples (10mm x 10mm). the hardened samples were then tempered at 150, 250oc, 350oc, 450oc, 550oc and 650oc respectively for 25 minutes. all heat treatments were performed using protherm furnace, model 140/25. table i: chemical composition of 420 martensitic stainless steel after tempering treatment, all the samples were investigated for their hardness with rockwell hardness tester (wolpert tester model n23ab) for all corresponding heat treatments as well as toughness was measured element wt.% c 0.34% si 0.40% mn 0.38% p 0.03% s 0.02% cr 12.67% ni 0.29% mo 0.08% iftikhar (et.al), effect of tempering temperature on the properties of martensitic stainless steel aisi-420 (pp. 51 56) sukkur iba journal of emerging technologies sjet | volume 2 no. 1 january – june 2019 © sukkur iba university 53 through charpy impact test according to astm standard e-23. the steel samples were then grounded, polished and etched using vilella’s reagent (90ml ethanol, 10ml hcl and 2gm picric acid). microstructure of these samples were studied at optical microscope as well as scanning electron microscope over and above, energy dispersive x-ray (edx) to verify the precipitated types of carbide in the microstructure. 4. results and discussion the hardness value of 92 hrb is measured from as-received sample which is in annealed condition and contains the carbides precipitates in fully ferritic matrix. after quenching from austenitizing temperature of 1050°c in oil medium, this hardness value is measured to be 58.5 hrc and the toughness as 7 j as shown in figure 1. this high hardness is attributed to the formation of lath martensitic structure, shown in figure 2. this as-quenched structure of fresh lath martensite is quite brittle and should be stress-relieved or tempered to restore some ductility. the little amount of carbides which was not dissolved at austenitizing temperature is also present in lath martensite matrix. the ms temperature of aisi 420 is found to be 380°c with carbon content of 0.34%. fig 1:hardness and toughness versus tempering temperature fig 2:optical micrograph of as quenched microstructure containing carbides in lath martensitic matrix. 4.1. tempering at 150°c by tempering up to 150°c, slight change in hardness and toughness with 58 hrc and 7j respectively as shown in figure 1, was observed because of the softening effect due to the depletion of carbon from martensite matrix is compensated by the precipitation of well-dispersed carbides but no increase in carbide precipitation occurs. according to porter and easterling [6], the carbide identified at this tempering temperature, as shown in figure 3, is the transition-carbide fe2.4c of diameter 2nm due to some partial diffusion of carbon from supersaturated martensite. 4.2. tempering at 250°c at tempering temperature of 250°c, hardness of the steel drops to 52 hrc with significant increase in toughness of 42.5 j. during tempering between approximately 149°c and 316°c, a relaxation of the martensite structure occurs whereby the volumetric stresses associated with the formation of martensite upon quenching are relieved [7]. volumetric stresses result in martensite structure decreasing in hardness iftikhar (et.al), effect of tempering temperature on the properties of martensitic stainless steel aisi-420 (pp. 51 56) sukkur iba journal of emerging technologies sjet | volume 2 no. 1 january – june 2019 © sukkur iba university 54 while according to figure 1, at the same temperature the high impact energy is due to the presence of retained austenite within the lath martensite, which is very soft as related to martensite, absorbing fracture energy. according to [8], tempering the hardened steel at 250°c facilitate precipitation of epsiloncarbides with restoration of distorted bct structure by diffusing some trapped carbon into matrix. at this temperature some epsiloncarbides start transforming to fe3c [6]. fig 3:optical micrograph hardened and tempered at 150°c. microstructure contains carbides in lath martensitic matrix. fig 4:optical micrograph hardened and tempered at 250°c. microstructure containing carbides in lath martensitic matrix 4.3. tempering at 350°c tempering at 350°c, the hardness then reached to 50 hrc and with decreases in toughness up to the value of 27.5 j as shown in figure 1. decreases in hardness show that the relaxation of martensite persisted above 250°c while decrease in toughness is the result of tempered martensite embrittlement (tme) caused by the precipitation of carbides (fe3c) occurring at the expense of epsiloncarbide. tempered martensite embrittlement is thought to be resulted from the combined effects of cementite precipitation on prioraustenite grain boundaries or inter lath boundaries and the segregation of impurities at prior-austenite grain boundaries. besides if at grain boundary, the morphology of m3c is predominantly more sheet-like and this would be the prime cause of low ductility in this temperature range. the transformation of retained austenite into ferrite and cementite also causes temper embrittlement [6]. 4.4. tempering at 450°c the hardness as calculated at 450°c is 52.5 hrc with toughness 15 j as shown in fig.1. the increase in hardness in this range is attributed to secondary hardening phenomenon, which is due to the complexforming carbides having noticeable effect on the retardation of softening and increase in hardness. it has been illustrated that the m3c carbides are first detected after 200°c and these carbides remain until 450°c [9] but it was stated by isfahany [4] that in the temperature range of 400-500°c, m7c3 starts to form within the martensitic laths. above 350°c, the m3c carbides progressively dissolve and m7c3 carbides start precipitating. a small amount of retained austenite is also remained as shown in figure 6. iftikhar (et.al), effect of tempering temperature on the properties of martensitic stainless steel aisi-420 (pp. 51 56) sukkur iba journal of emerging technologies sjet | volume 2 no. 1 january – june 2019 © sukkur iba university 55 4.5. tempering at 550°c with further increase in temperature at 550°c, the hardness drops to 51 hrc. this is due to softening phenomenon taking place when the m7c3 carbides start to coarsen which also caused drop off toughness to 12.5 j. due to coarsening, m7c3 partially transform to m23c6 carbides [4] which is more stable form of carbides and remained at all temperature. 4.6. tempering at 650°c here the hardness value is rapidly decreased to 36hrc and an increase in toughness occurs with 17 j. the softening occurs due to start of recrystallization above 600°c, as near to the sub-critical annealing range for aisi 420 that is to be 675-705°c [7]. after this temperature m23c6 carbide, occurring at the expense of m7c3, start to coarsen causing measurable decrement in hardness. the increase in toughness and decrease in hardness is due to recovery of meta stable martensitic phase but the lath structure remains [6] as shown in fig.8. toughness should be considerably enhanced around 650-700°c temperature range but the ductility was restricted by the presence of coarse carbides, even however tempered martensite was present. fig 5:optical micrograph hardened and tempered at 350°c. microstructure contains m3c carbides in lath martensitic matrix fig 6:optical micrograph hardened and tempered at 450°c. microstructure contains carbides with retained austenite in lath martensitic matrix fig 7:optical micrograph hardened and tempered at 550°c. microstructure containing carbides in lath martensitic matrix 5. conclusion an investigation of the effect of tempering temperature on aisi 420 martensitic stainless steel was conducted. after interpreting the results of this study on the basis of mechanical testing such as hardness and toughness and optical microscopy, the chief findings in this work are summarized as follows: iftikhar (et.al), effect of tempering temperature on the properties of martensitic stainless steel aisi-420 (pp. 51 56) sukkur iba journal of emerging technologies sjet | volume 2 no. 1 january – june 2019 © sukkur iba university 56 fig 8:optical micrograph hardened and tempered at 650°c. microstructure containing carbides in lath martensitic matrix 1. nice combination of mechanical properties of aisi 420 martensitic stainless steel can be obtained by tempering near the range of 250oc with soaking time of 25 minutes as per dimension of 10x10mm sample. 2. secondary hardening was obtained between the tempering temperatures of 400500°c because of formation of secondary carbides m7c3. hence this temperature range should be avoided if good toughness is required. 3. decrease in toughness was observed between the tempering temperatures of 350550⁰c. 4. the toughness again improved with rapid decreased in hardness of 36 hrc at 650⁰c due to start of recrystallization above 600°c, as the sub-critical annealing range for aisi 420 was found to be 675-705°c. at this temperature m23c6 carbides coarsened and this resulted in measurable decline in hardness. acknowledgement we would like to acknowledge department of metallurgical engineering of ned university of engineering and technology, karachi for provision of facilities regarding this work and all the support and cooperation. references [1] bhadeshia, h.k.d.h. and honeycombe, r.w.k., steels: microstructure and properties, fourth edition, elsevier, 2017. [2] astm, aime, advances in the technology of stainless steel and related alloys, philadelphia, 1965. [3] isfahany, a. n., saghafian, h. and borhani, g., the effect of heat treatment on mechanical properties and corrosion behavior of aisi 420 martensitic stainless steel, journal of alloys and compounds, 509, pp 3931–3936, 2011. [4] stainless steel – grade 420 (uns s42000), www.azom.com/article.aspx?articleid=972/, 2013 [5] xu, m.l., secondary carbide dissolution and coarsening in 13% cr martensitic stainless steel during austenitizing, mechanical engineering dissertations, paper 23, 2012. [6] asm international, asm handbook heat treating volume 4, 1990. [7] rajasekhar, a., reddy, g.m., mohandas, t. and murti, v.s.r., influence of austenitising temperature on microstructure and mechanical properties of aisi 431 martensitic stainless-steel electron beam welds, materials and design, 2008. [8] porter, d.a. and easterling, k.e., phase transformation in metal and alloys, third edition, taylor and francis group, 2009 [9] calliari, i., zanesco, m., dabala, m., brunelli, k. and ramous, e., investigation of microstructure and properties of a ni-mo martensitic stainless steel, materials and design, 29(1), pp 246–250, 2008. format template vol. 2, no. 2 | july december 2019 sjet | p-issn: 2616-7069 | e-issn: 2617-3115 | vol. 2 | no. 2 | © 2019 sukkur iba 7 analysis of basic spatial gait parameters in laboratory shehla inam1 and muhammad waqar2 abstract: human gait is performed by the locomotion of the lower limbs. the basic spatial parameters of gait cycle were measured in laboratory for the young healthy subjects including 13 females and one male in two conditions i.e. barefoot (assuming healthy gait) and wearing only one shoe (assuming unhealthy or compensated gait). the comparison between the two conditions was studied for the average values of step length, stride length, base of support and step width. also, the standard deviation and coefficient of variance were calculated individually for each parameter of healthy subjects. the average values of the initial three parameters were greater for the healthy subjects while the fourth parameter calculated was greater for the unhealthy subjects. keywords: basic gait parameters; gait analysis; spatial gait parameters; gait laboratory studies 1 department of biomedical engineering, riphah international university, islamabad, pakistan 2 department of biomedical engineering and sciences, national university of sciences and technology islamabad, pakistan *corresponding author: shehlainam10@gmail.com 1. introduction a gait cycle is the time period during which one of the legs is initially in contact with ground and after going through seven events of locomotion starting with initial contact, comes back to its initial position [3]. the gait analysis of a patient could help in revealing certain biomechanical problems which could be cured either through medical equipment, physical therapy or surgery. also, this includes the neural and muscles pain [12] rehabilitation plays and important role in coping up the injuries that are encountered in sports. rehabilitation process involves certain steps designed in [2]. tommy oberg et.al studied the basic gait parameters of 233 subjects in a 5.5 m long gait laboratory including both men and women. the parameters were measured for the slow, medium and fast gait. they found the significant age-variability in walking speed and step length for normal and fast gait and the effect of age and sex for normal and fast gait [1]. m.m. samson et.al investigated the effects of age, weight and height on the normal walking speed of the healthy subjects including both men and women. they used certain devices such as kistler force plates for cadence measurement, an infrared reflecting system for measuring the walking speed and the stride length via the formula. they concluded that cadence did not depend upon the age, weight and height while the stride length and walking speed reduced with the age [4]. emily a. ready et.al investigated the effects of auditory cues on the gait of healthy shehla (et al.), analysis of basic spatial gait parameters in laboratory (pp. 07 12) sukkur iba journal of emerging technologies sjet | volume 2 no. 2 july – december 2019 © sukkur iba university 8 subjects depending on their ability of beat perception while following certain conditions. thus, the spatiotemporal gait parameters were influenced when walking to musicand metronome-based rhythmic auditory stimuli [5]. in [6], the relationship between two gait parameters i.e. in-laboratory gait speed measured through pressure sensor of a sheettype and daily gait speed via accelometer was investigated among the older subjects. the relationship between both parameters was found out to be low, however, the average daily gait speed was significantly lower than average in-laboratory gait speed. claudiane a.fukuchi and marcosduarte proposed a simple method to predict the gait pattern of the subjects based on their speed by creating a reference database consisting a range of gait speeds and predicted database for gait pattern. thus, the predicted data was the same compared with the experimental measures for the joint angles and joint moments [7]. pierre martz et.al assessed the influence of body mass index on the gait parameters of the patients including both obese and non-obese patients suffering from total hip anthroplasty before and after the six months of surgery. the patients had shown a significant functional improvement regardless of bmi [8]. roth et.al studied the relationship between the spatial parameter i.e. speed of walk and the 18 temporal parameters among the patients of one-month hemiplegia. the experiment was performed with the help of footswitches connected to portable device. the speed was found to be corelated with most but not all the temporal parameters [9]. in [10], the authors studied the difference in the biomechanic parameters among the healthy and the moderate and chronic osteoarthritis patients. they concluded that the knee osteoarthritis patients showed results such as lower knee and ankle joint moments, ground reaction forces, knee reaction force and knee excursion on desired speed. there was decreased knee joint excursion for all conditions during analytic differences in walking speed. m.ambrus et.al analyzed the difference in the stride length-cadence relationship among fifteen patients of parkinson’s disease and fifteen age-matched subjects both on treadmill and overground through linear regression. it was observed that the treadmill had positive impact on the gait of patients of parkinson’s disease [13]. the differences in kinetic and kinematic were studied during the landing mechanics of a single leg drop jump between an athlete suffering from no acl injury history in their past and an athlete who suffered from the acl reconstruction surgery. the latter had low range of their hip, ankle and knee motion in two planes i.e. sagittal and frontal during a single drop jump and had relatively higher ground reaction forces [14]. fig. 1 seven events of gait cycle 2. methodology 2.1. subjects recruitment the seven parameters of gait of 14 subjects including 13 females and one male of age (21.38±1.64), weight (56.57 ±10.03) and height (64.92″±3.53) were measured and studied. the experiment was performed with the consent of subjects in the laboratory of department of biomedical engineering, riphah international university, islamabad. 2.2. measurement of parameters the parameters that were measured included step length, step width, stride length, base of support, stride length/ length of lower extremity and cadence. the study was undertaken in such a way that the subjects were asked first to perform the gait barefoot. shehla (et al.), analysis of basic spatial gait parameters in laboratory (pp. 07 12) sukkur iba journal of emerging technologies sjet | volume 2 no. 2 july – december 2019 © sukkur iba university 9 this was assumed as a healthy gait. next, they were asked to perform an unhealthy or compensated gait. this was done by wearing one shoe in one foot and the other left barefoot. this gave an expression of a compensated gait because of the difference in the height of both feet and also the change in their gait was observed. all the desired parameters were measured with the help of a long scale of 100 centimeters and a stop watch was used to calculate the cadence. in cases, where the measurements exceeded 100 centimeters, a point was marked, and the measurements were added by putting the scale on the marked point and re-measuring from the initial value of the scale i.e. 1 centimeter. the comparison between the assumed healthy and unhealthy subjects was studied only for four parameters i.e. step length, stride length, base of support or walking base and step width. after measuring each parameter of all the subjects, the average, standard deviation (st.dev.), and coefficient of variance (cv) for each parameter were calculated as shown in table ii. table i: gender information of each subject 2.3. gender information before carrying out experiment, the basic information including the gender, height, weight, dominant leg, history of injury, flat footness and family history of each subject was recorded as shown in table i. 3. results and discussion the parameters for the healthy gait of the subjects that were measured are shown in table ii. table ii: measured parameters of healthy subjects likewise, the parameters for the unhealthy gait that were measured are shown in table iii. 3.1. step length the step length is the distance covered by one right and left leg as shown in fig. 2. the subjects were asked to only take a step and stand on the same position. initially, the value was measured by standing barefoot. next, each subject was asked to wear a shoe only in one foot and the other foot bare which depicted as the compensated or unhealthy gait. hence, in both cases, the values were measured with the help of a long scale in centimeters from the heel of trailing foot to shehla (et al.), analysis of basic spatial gait parameters in laboratory (pp. 07 12) sukkur iba journal of emerging technologies sjet | volume 2 no. 2 july – december 2019 © sukkur iba university 10 the heel of leading foot. the average of the values obtained is shown in fig.3 table iii: measured parameters of unhealthy subjects . fig. 2: walking base (bos), step length and stride length [3] the fig. 3 shows that the step length of the healthy subjects i.e. having worn no shoes had a greater step length as compared to those wearing only one shoe. this could be because the muscles of the healthy subjects were more active and felt no hindrance in performing the step because of greater stability. however, the unhealthy subjects did require taking relatively smaller steps to not losing their balance. fig 3: healthy vs unhealthy step length 3.2. stride length the stride length is the distance covered by two consecutive steps as shown in figure 3. each subject was asked to firstly, take steps barefoot and next time, take steps while wearing only one shoe. thus, the values were measured with the help of a long scale in centimeters by measuring the distance from the heel of the already heading foot when one step was taken previously, and to the heel of the foot which was brought ahead of it to take another step. the average of the values is shown in fig. 4. fig 4: healthy vs unhealthy stride length from figure 4, it can be observed that the stride length of the healthy subjects was shehla (et al.), analysis of basic spatial gait parameters in laboratory (pp. 07 12) sukkur iba journal of emerging technologies sjet | volume 2 no. 2 july – december 2019 © sukkur iba university 11 greater as compared to that of unhealthy subjects due to covering a large distance and taking longer steps. their muscles had more control in maintaining stability and performing stable steps. 3.3. base of support or walking base the base of support as shown in figure 2 is actually the area covered by the whole length of the foot. hence, it was measured by measuring the length of the foot with the help of a scale in centimeters by placing both the feet still. the average of the values of the base of support obtained for both cases i.e. healthy (barefoot) and unhealthy (one foot with shoe) is shown in fig. 5. fig. 5 shows that the base of the support for the unhealthy subjects is smaller than those of healthy subjects. it may be because the subjects with abnormal gait require greater stability to stand on their feet as compared to those with a normal gait. fig 5: healthy vs unhealthy walking base 3.4. step width the step width as shown in figure 6 is the horizontal distance between the two feet while taking a step. thus, it was measured by measuring the distance horizontally from the heel of the leading foot to heel of the trailing foot in both cases i.e. healthy and unhealthy gait. the figure 7 shows the average values of the step width for both cases. fig 6: step width [11] fig 7: healthy vs unhealthy step width it can be observed from the figure 7 that the average value of step width of unhealthy subjects is relatively greater than those of healthy subjects. this may be because they require greater step width to increase their balance and stability. however, the other parameters i.e. cadence, and the ratio stride length/ lower extremity were not measured for the unhealthy condition of the subjects. 3.5. cadence cadence is the number of steps taken in one minute. thus, the healthy subjects were asked to perform the gait barefoot in their normal speed in one minute. the values were recorded with the help of a stop watch which are shown in table ii. however, cadence of the unhealthy subjects was not calculated. shehla (et al.), analysis of basic spatial gait parameters in laboratory (pp. 07 12) sukkur iba journal of emerging technologies sjet | volume 2 no. 2 july – december 2019 © sukkur iba university 12 3.6. stride length/ lower extremity length (sl/lel) the lower extremity’s length was measured by tape measurement from greater trochanter to lateral maleollus. thus, the ratio of sl/lel was calculated for the healthy gaited subjects as shown in table ii. the average value calculated is 1.2±0.9. 3.7. speed the walking speed of the healthy or barefoot gait of the subjects was measured by formula, speed= step length* cadence the values calculated for the speed could be observed in table ii. the average value for the speed of healthy gaited subjects calculated is 46.5±17.4. 4. conclusion the basic gait parameters play a vital role in the overall gait performance of a person. thus, an experiment was carried out to study the basic spatial parameters of the healthy subjects in two conditions i.e. once barefooted and next wearing only one shoe assuming it as compensated gait. the parameters such as step length, stride length and base of support of the healthy gaited subjects were greater as compared to that of unhealthy gaited subjects. however, the step width of the unhealthy gaited subjects was greater. moreover, the other parameters i.e. cadence, sl/lel and speed were measured only for the healthy subjects. the studies on these parameters for the compensated gait could play a vital role in the future research. references [1] a. k. a. k. o. tommy oberg, "basic gait parameters: reference data for normal subjects,," journal of rehabilitation research, pp. 210-223, 1993. [2] k. jg, "introduction to rehabilition," clinics in sports medicine, 2010. [3] v. s. j. s. d. ashutosh kharb, "a review of gait cycle and its parameters," in ijcem international journal of computational engineering & management, 2011. [4] a. c. l. d. v. a. g. d. a. d. j. j. v. m. m. samson, "differences in gait parameters at a preferred walking speed in healthy subjects due to age, height and body weight," aging clinical and experimental research, vol. 13, no. 1, pp. 16-21, 2001. [5] e. a. et.al, "beat perception ability and instructions to synchronize influence gait when walking to music-based auditory cues," elsevier, vol. 68, pp. 555-561, 2019. [6] n. t. et.al, "relationship between daily and in-laboratory gait speed among healthy community-dwelling older adults," scientific reports, 2019. [7] c. a. a. marcosduarte, "a prediction method of speed-dependent walking patterns for healthy individuals," elsevier, vol. 68, pp. 280-284, 2019. [8] p. m. et.al, "influence of body mass index on sagittal hip range of motion and gait speed recovery six months after total hip arthroplasty," international orthopaedics, 2019. [9] r. et.al, "hemiplegic gait: relationships between walking speed and other temporal parameters1," american journal of physical medicine & rehabilitation, vol. 76, no. 2, pp. 128-133, 1997. [10] [10] j. a. z. j. a. j. s.higginsonb, "differences in gait parameters between healthy subjects and persons with moderate and severe knee osteoarthritis: a result of altered walking speed?," elsevier, vol. 24, no. 4, pp. 372-378, 2009. [11] p. a. a. b. mullarney, "the relationship between pedestrian loading and dynamic response of an frp composite footbridge," bridge structures, 2018. [12] a. c. lee, "chapter 5: physiologic and pathologic gait," in principles and practice of pain medicine. [13] j. a. m.-d.-o. m.ambrus, "walking on a treadmill improves the stride length-cadence relationship in individuals with parkinson’s disease," gait and posture, vol. 68, pp. 136140, 2019. microsoft word a 100 kw high voltage power supply for dual energy computer tomography applications pmc2014pap short 4pp 18feb vol. 2, no. 2 | july december 2019 sjet | p-issn: 2616-7069 | e-issn: 2617-3115 | vol. 2 | no. 2 | © 2019 sukkur iba 1 a high state of modular transistor design on a 105 kw hvps for x-rays tomography applications hamayun khan1,4, muhammad yousaf ali khan1, qaisar bashir2 amad ud din3, kashif janjua4 ,shahid khan5 abstract: x-rays tomography work for the production of enhanced imaging at low radiation rate. this technique uses two tube of high voltage input power supply (hvps) at different values, but such type of technique is so expensive. another technique that have single tube of high voltage power supply have the ability to produce same high voltage at high rate of switching. this technique is so fast and less costly than the previous technique. in this paper, such type of high voltage input power supply (hvps) technique is used. this technique consists of high state of modular transistor known is igbt. the igbt converts the applied power supply into high voltage power as input supply (hvps) at the rate of 71 khz, due to which the efficiency is increases to work for high values of load. this technique is tested for both resistive load and x-ray tube and their results are presented. this developed technique is also usable for other applications which are operated on high voltage power supply (hvps). 3 keywords: x-ray, high voltage power supply (hvps) 1. introduction x-ray tomography works to radiate rays to obtain images of an object at different level of applied voltage. as we know xrays have the ability to have different attenuation at the different level of energy. as a result, the images have more information about every parts of the object as compared to mano energy scan techniques. to replace dual scanning of an object the ct scanners were introduces of dual source. now days this technology is so entrenched [1]. this 1 department of electrical engineering, gomal university, d.i.khan, kpk, pakistan 2 department of electrical engineering, university of lahore, lahore punjab, pakistan 3 department of physics, fatima jinnah women university, rawalpindi, pakistan 4 department of electrical engineering superior university, lahore, punjab, pakistan 5 united consulting services, d.i.khan, kpk,pakistan technique consists of high voltage two tube for input power supply. one tube has high voltage typically 140 kv and the other have low voltage typically 80kv, but unfortunately this technique is so costly another technique we want to introduce that have single tube of high voltage power supply having the ability to produce the same voltages as in the previous technique at high switching to change from voltage level to another, as result we can use multi-level of energy with one single tube. hamayun (et.al), a high state of modular transistor design on a 105 kw hvps for x-rays tomography applications (pp. 01 06) sukkur iba journal of emerging technologies sjet | volume 2 no. 2 july – december 2019 © sukkur iba university 2 there are some basic ideas, e.g., in [2, 3]. the modulation in the range frequency will be 10100 hz depend on the uses and our need the switching from one level of energy to another is so fast typically less than 100-200 μs that generate quasi-rectangular pulses such type of technique gives excellent performance at low cost such technique in case of dc is known as a long-pulse hvps. generally, there are some devices which increase the size of the charging power but decrease the output efficiency. we need to overcome these types of challenges [4]. when the frequency is increased without the use of converter module as a result efficiency is going to decrease. in this paper we have to abolish this type of weakness and bring the developmental work for ct & de. heat control by using separate hardware architecture and bit-partitioning method is illustrated in [5]. the author considered an extra efficient mechanism by inducing newer memory chips for accessing register files. bitpartitioned register file (bprf) from basic cache organization mechanism is considered. it is designed on a conventional dynamically scheduled superscalar processor [6, 7]. 2. main design parameters high voltage power supply ct scan have major application in the field of medical which have maximum power of about 105 kw. our major target is to bring down the size and also the cost. we have to make hvps so strong that it can support the rotational force of typically 50 g. hvps have two tube for power supply and also high-speed rotor for the rotation of anode. the specifications are shown in table 1, the expository part of the high voltage power supply technology is focused conversion from dc to dc. the hvps has the flexibility and compatibility applications which are the main features. 3. hvps design the simplified block diagram is shown in below figure 1. the small size and low-cost capacitive filter are used in the ac chassis. the chassis filter, the large component of rl is at the hv side. an inductive adder is used for the conversion of dc to dc which consists of two module m1and m2 which phase shifted the hf ripple suppression [8]. while satisfying the specification of hf ripple with the help of two circuit known as voltage multiplicative r1, r2. the high frequency switching circuit has low capacity typically of less than 200 pf. due to this the converter is so nimble and useful for fast transition of low voltage state to high voltage state. as we know there are two inverter cells m1 and m2 as shown in below figure consisting of halfbridge inverters inv1, inv2. the zerocurrent switching (zcs) mode, the inverter is operated in low line while at full load the inverter operates at 70khz. in the other mode, the low frequency is observed. the igbt is used which has less loss and low cost [11, 12]. table i: descriptions of hvps for de applications. hamayun (et.al), a high state of modular transistor design on a 105 kw hvps for x-rays tomography applications (pp. 01 06) sukkur iba journal of emerging technologies sjet | volume 2 no. 2 july – december 2019 © sukkur iba university 3 fig 1: block-diagram of hvps. the two transformers t1 and t2 are operated by eight inverters and each transformer have four inverters which are enabled and disabled according to the current operational condition. as the hv transformers have leakage inductance which consists of resonant tank circuits so there is no need of external inductors. the inverter consists of two chassis known as inverter chassis as shown in figure 2 and high voltage chassis as shown in figure 3. high voltage chassis provide insulation for hardness while inverter chassis have importance for the high rotational force of typically 50g. a lot of stress is observed on insulation and other parts during the pulse mood operation. we should need specific insulation system at de pulse mode. the insulation design is best after testing obliges by fea. fig 2: inverter chassis having weight of 37kg. fig 3: high voltage chassis consist of two transformers having secondary of 140kv. the base of control section is fpga which has standard features and so fast digital processing which consist of multiple protection like arc/spark, overheating of major component, over or under current and voltage and the interlock through current and voltage programing. in the frequency mode the inverters are active to regulate the output. when the load voltage in switching frequency increases for every period ts, the pid control are not able to obtain the flat-top pulses in the wide range of input lines and loads which is changeable task in the case when line and load are fixed. when the load voltage raises the inverter operates at maximum frequency and as result h v d iv id e r v loa d gate 2 t2 m gate 1 t1 ma fdbk kv fdbk + arc lim r1 inv r2 inv m 2 c chassis contr ol boar d hamayun (et.al), a high state of modular transistor design on a 105 kw hvps for x-rays tomography applications (pp. 01 06) sukkur iba journal of emerging technologies sjet | volume 2 no. 2 july – december 2019 © sukkur iba university 4 maximum power charging is obtained and reaches to the desired level. at this stage the converter is in feedback control and frequency is derived by this equation. 2 4 l s r r p f c v= where l p = load power s f = switching frequency r c = resonant frequency r v = dc rail voltage 2 2 * 2 l ct r r p f c v = (1) we observed that pspice model of hvps is at full scale. all the features of hvps are reproduced which are phase shifted in addition to the feedback loop. 4. experimental results many hvps are manufactured on compliance for specification. the wave form is obtained for resistive load and x-ray load are given below. figure 4 is the wave form that is obtained for resistive load with high voltage switching in the range of -80kv to -135kv. the rise time is 100us at which power is high typically at 105kw for low load and decreases at high load. figure 5a shows low line collector current at full power. the zero current switching (zcs) remains the same and switching frequency reach to 70 khz. at lower load and high load, the (zcs) is also observed. primary current which is phase shifted of the transformer t1, t2 having two inverters inside each module m1 and m2. at high load the collector current is indicated as shown in figure 5b. due to non-ideal decoupling in each module some asymmetry is produce in the primary current. when the test is started for the x-ray tube there should be measurable device to measure the external applied voltage so that we will be able to provide the needed voltage to the xray tube. if the external applied voltage is less than the needed voltage, then the feedback divider is used to increase the external applied voltage. fig 4: resistive load= 181 kt. high voltage= -135kv low voltage= -80kv prr=200 hz. fig 5a: low line collector current and full power. hamayun (et.al), a high state of modular transistor design on a 105 kw hvps for x-rays tomography applications (pp. 01 06) sukkur iba journal of emerging technologies sjet | volume 2 no. 2 july – december 2019 © sukkur iba university 5 fig 5b: collector current due to non-ideal decoupling. fig 6: x-ray tube. high voltage= -135kv low voltage= -80kv load current= 533ma ppr= 200hz to operate the x-ray tube efficiently, the maximum error is 1.5% due to the changing of the applied voltage after 200us. the wave form obtained during this operation are given in figure 6, and figure 7. when the frequency of the wave is increased from 1 khz due to the rise and fall so that it takes another 100 usec to settle its efficient value. so, the average frequency for the implementation of this operation. fig 7: x-ray tube high voltage= -135kv low voltage= -80kv load current= 533ma ppr= 1500hz riseand fall time= 40 μs. the heat control by using separate hardware architecture and bit-partitioning method is illustrated in [1]. the author considered an extra efficient mechanism by inducing newer memory chips for accessing register files. bit-partitioned register file (bprf) considered their designing mechanism from basic cache organization mechanism. it is designed based on a conventional dynamically scheduled superscalar processor. when test for the resistive load is started, the operation duration is from 15 sec to 100 sec at power of 36 kw. all the components are also reliable. after some time, all the igbt in the inverters have base plate start to become overheat due to which the voltage drops increase the temperature produce in such a case are 37oc which is the worst case. 5. conclusion in this paper a hvps is developed which have high performance and low cost which is tested for both resistive load and also for the hamayun (et.al), a high state of modular transistor design on a 105 kw hvps for x-rays tomography applications (pp. 01 06) sukkur iba journal of emerging technologies sjet | volume 2 no. 2 july – december 2019 © sukkur iba university 6 x-ray tube. by using this technique, we are able to produce 105kw to 140kw power at the frequency rate of 1.5 khz by using single tube. references [1] m. p. musau, n. a. odero, and c. w. wekesa. “asynchronous interconnection of the proposed east africa power pool (eapp),” 2017 ieee pes power africa, june 2017, pp. 7-11. [2] c. chen, k. zhang, k. yuan, z. gao, x. teng, and q. ding. “disturbance rejection-based lfc for multi-area parallel interconnected ac/dc system,” iet generation, transmission & distribution, vol. 10, no. 16, pp. 4105-4117, dec. 2016 [3] x. zheng, y. chen, h. chen, y. zhang, j. zhu, j. chen, and p. xuan. “loss-minimizing generation unit and tie-line scheduling for asynchronous interconnection,” ieee journal of emerging and selected topics in power electronics, to be published, doi: 10.1109/jestpe.2017.2783930 [5] h. khan, m. u. hashmi, z. khan, and r. ahmad, “offline earliest deadline first scheduling based technique for optimization of energy using storm in homogeneous multicore systems,” ijcsns int. j. comput. sci. netw. secur. vol.18 no.12, december 2018, vol. 18, no. 12, pp. 125–130, 2018. [6] h.e. daniels et al., “dual voltage x-ray switching system”, european patent 052 269, 1985. [7] b. m. gordon et al., “dual energy power supply”, us patent 5,661,774, aug. 26, 1997. [8] h. khan, m. u. hashmi, z. khan, r. ahmad, and a. saleem, “performance evaluation for secure des-algorithm based authentication & counter measures for internet mobile host protocol,” ijcsns int. j. comput. sci. netw. secur. vol.18 no.12, december 2018, vol. 18, no. 12, pp. 181–185, 2018 [9] c. loef and g. zeitler, “power supply for an x-ray generator system comprising cascade of two voltage sources”, european patent ep 2 207 405 b1, 2013. [10] a. pokryvailo, c. carp, and c. scapellati, “a high-power high voltage power supply for long-pulse applications”, ieee transactions on plasma science, vol. 38, no. 10, october 2010, pp. 2604-2610. [11] a. pokryvailo, c. carp, and c. scapellati, “high power, high performance, low cost capacitor charger concept and implementation”, ieee transactions on plasma science, vol. 38, no. 10, october 2010, pp. 2734-2745. [12] a. pokryvailo, c. carp and c. scapellati, “highly efficient switchmode 100-kv, 100kw power supply for esp applications”, proc. 11th int. conf. on electrostatic precipitation, hangzhou, 21-24 oct., 2008, pp. 284-288 format template vol. 1, no. 1 | january june 2018 sjet | issn: 2616-7069 | vol. 1 | no. 1 | © 2018 sukkur iba 57 power quality analysis of controlled rectifiers and their impact on input power system abdul ghaffar1,engr. jahangir badar soomro1,altaf hussain1, dr. faheem a. chachar1 abstract: this paper introduces the power quality analysis of ac-dc converter topologies and discusses their impact on input power system. due to latest advancement in the technologies and power semiconductor devices, it is impossible to put barriers for the applications of power electronics topologies. these topologies are of different structure and causes harmonics when connected to the power system, these harmonics affects not only the power quality of the system network but also increase conductor overheating and core losses in motor applications. due to their wide usage of rectifiers, it is necessary to observe its impact on the input power system, which includes thd (total harmonic distortion) and distortion in the input power factor etc. this research work focuses on the power quality analysis of the input power system due to ac-dc converters. in this paper input thd of single-pulse, two-pulse and six-pulse controlled rectifiers are examined using fft analysis in matlab its effect on input power system are also observed. 1. introduction the ac-dc converter is by far the largest group of power switching circuits applied in industrial applications [1-3]. usually rectifiers are developed using diodes and thyristors to provide uncontrolled and controlled dc power at the output with unidirectional and bidirectional power flow [4]. the drawback that comes with these rectifiers is that they cause non-linearity in the system which causes the harmonics to be injected in the system. these harmonics cause current distortion as well as poor power factor at the input side. the difference between a linear and nonlinear load is that a linear load is a load which 1 dept. of electrical engineering, sukkur iba university, sukkur, pakistan corresponding email: aghaffar.es14@iba-suk.edu.pk draws current from the supply which is proportional to the applied voltage, whereas a load is considered non-linear load when its impedance changes with the applied voltage, due to that change in impedance current drawn by the load is non-linear and that non-linear current carries harmonics with it. the power electronics converters also lie in the family of non-linear load. “ieee 519-1992 defines harmonics as a sinusoidal component of a periodic wave or quantity (e.g. voltage or current) having a frequency that is an integral multiple of the fundamental frequency” [5]. harmonics causes many unwanted effects in the system network. the most saviour effect mailto:aghaffar.es14@iba-suk.edu.pk abdul ghaffar (et al.), power quality analysis of controlled rectifiers and their impact on input power system. (pp. 57 65) sukkur iba journal of emerging technologies sjet | volume 1 no. 1 january – june 2018 © sukkur iba university 58 is the heating of equipment caused by iron losses and copper losses. a simple three phase nonlinear load is six-pulse rectifier and this type of load produces a significant amount of harmonics in the system network. harmonics are not only generated by the non-linear loads but also the linear loads like rotating machines or transformers but their magnitude is quite low. increasing the number of pulses of rectifiers like six-pulse, twelve-pulse decreases the effect of harmonics by the formula h = np ± 1 where n is the number integer. p is the number of pulses. h is the harmonics order. this paper comprises the comparative analysis of the harmonics effect of rectifier topologies (i.e. single-pulse, two-pulse, sixpulse and twelve-pulse) and their effect on input supply as well as on input power factor at different power factor using different loads. 2. methodology for performing the experimental study and analysis of harmonics generation rectifiers the approach would be as designing of different topologies of rectifiers. for each configuration, the simulation would be done through matlab/simulink. the simulated waveforms of current and voltage in case of different loads would be obtained by taking different firing angles and then correlate the effectiveness of different model and its configurations. due to switching operations of ac-dc converters non-linearity is produced in the input current due to which harmonics are generated [6] which not only disturb the performance of converters but also quality of input power system is badly affected. the power quality factor would be observed by the fluke power quality analyzer that can monetize the cost of energy waste due to poor quality. the implementation of different rectifiers circuits i.e. single pulse, two pulse, six pulse and twelve pulse would be done on simulation on matlab/simulink using different techniques over different loads. 3. single phase half wave rectifier power converters are used whenever there is mismatch between power supply available and load requirement. the thyristor can be triggered at any angle α in positive half cycle as well as in negative half cycle so that the output voltage can be controlled. the thyristor acts as an open during the negative half cycle [7]. 3.1. single phase half wave controlled rectifier with r load fig. 1. shows half wave controlled rectifier with resistive load. this topology is also known as 1-pulse rectifier. fig. 1. half wave controlled rectifier with r load. fig. 2. input current and voltage with r load at firing angle of 45o. input voltage and current waveform at firing angle of 45o is shown in fig. 2. input current is no more a pure sinusoidal and fig. 3 shows input current harmonics at firing angle of 45o. abdul ghaffar (et al.), power quality analysis of controlled rectifiers and their impact on input power system. (pp. 57 65) sukkur iba journal of emerging technologies sjet | volume 1 no. 1 january – june 2018 © sukkur iba university 59 fig. 3. input current thd with r load at firing angle of 45o. output current and voltage with resistive load is shown in fig. 4. it can be seen from waveform that output is not pure dc and it contains ac components along with dc components. fig. 4. output current and voltage with r load at firing angle of 45o. table i. input, output, voltage thd, current thd and power factor with r load at different firing angles. firin g angl e input curren t thd % output curren t thd % output voltag e thd % input powe r facto r 30o 55.38 55.38 55.38 0.69 45o 66.54 66.54 66.54 0.67 60o 80.36 80.36 80.36 0.63 90o 115.24 115.24 115.24 0.50 it can be seen from table that harmonics generated are increased by increasing firing angle and current and voltage harmonics are same due to resistive load. also, input power factor decreases by increasing firing angle as shown in fig. 5. fig. 5. relationship of firing angle and input power factor. 3.2. single phase half wave controlled rectifier with rl load input current and voltage with resistiveinductive load is shown in fig.6. fig. 6. input current and voltage with rl load. it can be seen that keeping all parameters same, current harmonics in resistive-inductive load is reduced than resistive load as shown in fig. 7. inductor works as a filter for current harmonics and therefore current waveform becomes smoother. fig. 7. input current thd with rl load at firing angle of 45o. abdul ghaffar (et al.), power quality analysis of controlled rectifiers and their impact on input power system. (pp. 57 65) sukkur iba journal of emerging technologies sjet | volume 1 no. 1 january – june 2018 © sukkur iba university 60 output current and voltage with resistiveinductive load is shown in fig. 8. voltage and current waveform are different due to resistive-inductive load. fig. 8. output current and voltage with rl load. table ii. input, output, voltage thd, current thd and power factor with r load at different firing angles. firin g angl e input curren t thd % output curren t thd % output voltag e thd % input powe r facto r 30o 48.9 48.9 60.97 0.65 45o 57.07 57.07 72.39 0.62 60o 67.56 67.56 87.43 0.57 90o 93.73 93.73 127.5 0.42 in the above table it can be seen that the thd at the input side is increasing with the increase in the firing angle, also due to resistive-inductive nature of the load, the current ripples are filtered as an inductor opposes the change in current and due to this the current harmonics at the output is less than the voltage harmonics. it is observed that input power factor decreases with increase in firing angle as shown in fig. 9. fig. 9. relationship of firing angle and input power factor. 4. single phase full wave controlled rectifier a full-wave controlled rectifier converts both the positive as well as negative half cycle of input waveform and converts both polarities of the input waveform to pulsating dc. the desired value at the output can be achieved by varying the firing angle α of the thyristor [8]. 4.1 single phase full wave controlled rectifier with r load fig. 10. shows the single phase full wave controlled rectifier with resistive load. this topology is also known as 2-pulse rectifier. fig. 10. full wave controlled rectifier with r load. fig. 11. input current and voltage with r load. abdul ghaffar (et al.), power quality analysis of controlled rectifiers and their impact on input power system. (pp. 57 65) sukkur iba journal of emerging technologies sjet | volume 1 no. 1 january – june 2018 © sukkur iba university 61 input voltage and current waveform at firing angle of 45o is shown in fig. 11. input current is distorted sinusoidal and fig. 12 shows input current harmonics at firing angle of 45o. fig. 12. input current thd with r load at firing angle of 45o. output current and voltage with resistive load is shown in fig. 13. it can be seen from waveform that output is still not a pure dc and it contains ac components along with dc components but it has less ripple factor as compared to single phase half wave controlled rectifier. fig. 13. output current and voltage with r load. it can be seen form table that harmonics generated are increased by increasing firing angle and current and voltage harmonics are same due to resistive load. also input power factor decreases by increasing firing angle as shown in fig. 14. table iii. input, output, voltage thd, current thd and power factor with r load at different firing angles. firing angle input current thd % output current thd % output voltage thd % input power factor 30o 16.32 30.57 30.57 0.98 45o 26.8 33.47 33.47 0.95 60o 40.4 37.1 37.1 0.89 90o 70.39 57.5 57.5 0.70 fig. 14. relationship of firing angle and input power factor. 4.2 single phase full wave controlled rectifier with rl load input current and voltage with resistiveinductive load is shown in fig. 15. fig. 15. input current and voltage with rl load. it can be seen that keeping all parameters same, current harmonics in resistive-inductive load is reduced than resistive load as shown in fig. 16. abdul ghaffar (et al.), power quality analysis of controlled rectifiers and their impact on input power system. (pp. 57 65) sukkur iba journal of emerging technologies sjet | volume 1 no. 1 january – june 2018 © sukkur iba university 62 fig. 16. input current thd with rl load at firing angle of 45o. output current and voltage with resistiveinductive load is shown in fig. 17. voltage and current waveform are different due to resistive-inductive load. fig. 17. output current and voltage with rl load. table iv. input, output, voltage thd, current thd and power factor with rl load at different firing angles. firin g angl e input curren t thd % output curren t thd % output voltag e thd % input powe r facto r 30o 9.49 26.85 31.16 0.93 45o 16.4 21.51 33.47 0.89 60o 25.25 19.67 37.14 0.82 90o 49.39 37.22 56.65 0.62 it is observed that input power factor decreases with increase in firing angle as shown in fig. 18. harmonics increases due to increase in firing angle, thereby input power factor decreases. fig. 18. relationship of firing angle and input power factor. 5. three phase full wave controlled rectifier in industrial applications where three phase ac voltages are available it is preferred to use three phase rectifiers, as it gives us multiple benefits like high power handling, low ripple factor which reduces the filter size as well as low distortion at the input [9]. application of higher pulse rectifiers are found at various points like for pipeline pumps in petrochemical industry, for steel rolling mills in metal industry, for pumps in water pumping stations, for fans in cement industry, for traction in locomotive industry etc [10]. 5.1 three phase full wave controlled rectifier with r load fig. 19. shows three phase full wave controlled rectifier with resistive load. this topology is also known as 6-pulse rectifier. fig. 19. full wave controlled rectifier with r load. abdul ghaffar (et al.), power quality analysis of controlled rectifiers and their impact on input power system. (pp. 57 65) sukkur iba journal of emerging technologies sjet | volume 1 no. 1 january – june 2018 © sukkur iba university 63 fig. 20. input current and voltage with r load. input voltage and current waveform at firing angle of 45o is shown in fig. 20. input current is no more a pure sinusoidal and fig. 21. shows input current harmonics at firing angle of 45o. fig. 21. input current thd with r load at firing angle of 45. output current and voltage with resistive load is shown in fig. 22. six pulse rectifier has less ripple factor and thus requires smaller filter size. fig. 22. output current and voltage with r load. table v. input, output, voltage thd, current thd and power factor with r load at different firing angles. firing angle input current thd % output current thd % output voltage thd % input power factor 30o 35.55 75.62 75.62 0.51 45o 44.01 77 77 0.32 60o 62.09 78 78 0.13 it can be seen from the results that power quality of three phase rectifiers is better than single phase, also input power factor decreases by increasing firing angle as shown in fig. 23. fig. 23. relationship of firing angle and input power factor. 5.2 three phase full wave controlled rectifier with rl load input current and voltage with resistiveinductive load is shown in fig. 24. fig. 24. input current and voltage with rl load. abdul ghaffar (et al.), power quality analysis of controlled rectifiers and their impact on input power system. (pp. 57 65) sukkur iba journal of emerging technologies sjet | volume 1 no. 1 january – june 2018 © sukkur iba university 64 it can be seen that keeping all parameters same, current harmonics in resistive-inductive load is reduced than resistive load as shown in fig. 25. fig. 25. input current and voltage with rl load. output current and voltage with resistiveinductive load is shown in fig. 26. voltage and current waveform are different due to resistive-inductive load. fig. 26. output current and voltage with rl load. table vi. input, output, voltage thd, current thd and power factor with rl load at different firing angles. the results of six pulse rectifier for resistive-inductive load are shown in above table. the relationship of input power factor with firing angle is also demonstrate in fig. 27. fig. 27. relationship of firing angle and input power factor. 6. conclusion from the comparison of above results and relationship of higher pulses with thd it can be concluded that as we move towards the higher pulses, the thd at the input is decreased or simply the input supply distortion decreases with the increase in the number of pulses. another advantage is that filter size will reduce and filter losses will be minimized as we move towards higher pulses rectifiers. thus, ripple factor at the output of the higher pulse rectifiers (i.e. 12-pulse, 18-pulse and 24pulse) will be very less. the power factor is also less disturbed which also saves our economy as the disturbed power factor would increase the copper losses in the system as well as it would increase the stress on the switching devices, insulators and heating effect. in hvdc transmission system higher pulses rectifiers are preferred because of their huge advantages like economy, minimum losses and reliability. firing angle input current thd % output current thd % output voltage thd % inp ut po wer fact or 30o 38.65 56.40 75.64 0.4 7 45o 41.79 58 77.35 0.2 4 abdul ghaffar (et al.), power quality analysis of controlled rectifiers and their impact on input power system. (pp. 57 65) sukkur iba journal of emerging technologies sjet | volume 1 no. 1 january – june 2018 © sukkur iba university 65 references [1] b. k. bose, “recent advances in power electronics,” ieee transactions on power electronics, vol. 7, no. 1, pp. 2 – 16, 1992. [2] t. tanaka, s. fujikawa, and s. funabiki, “a new method of damping harmonic resonance at the dc link in large-capacity rectifierinverter systems using a novel regenerating scheme”, ieee transaction on industry applications, vol. 38, no. 4, page(s):1131 – 1138, july/august 2002. [3] o. garcia, m. d. martinez-avial, j.a. cobos, j. uceda, j. gonzalez, and j. a. navas, “harmonic reducer converter,” ieee transactions on industrial electronics, vol 50, no. 2, pp. 322 – 327, april 2003. [4] baharom, r., hashim, n. and hamzah, m.k., 2009, november. implementation of controlled rectifier with power factor correction using single-phase matrix converter. in power electronics and drive systems, 2009. peds 2009. international conference on (pp. 1020-1025), ieee. [5] f ii, i., 1993. ieee recommended practices and requirements for harmonic control in electrical power systems. new york, ny, usa. [6] mahar, m.a., larik, a.s., and shah, a.a., “impacts on power factor of ac voltage controllers under nonsinusoidal conditions,” mehran university research journal of engineering and technology, vol. 31, no. 2, pp.297-300, 2012. [7] solanki, a., “simulation & performance parameters analysis of single-phase full wave controlled converter using psim,” international journal of engineering research and general science, vol. 2, no. 3, pp.410414, 2014. [8] mahobia, s.k. and kumrey, g.r., “study and performance of singlephase rectifiers with various type of parameter,” international journal in engineering technologies and management research, vol. 3, no. 1, pp. 9-14, 2016. [9] mohan, n. and mohan, t.m., 1995. power electronics (vol. 3). new york: john wiley & sons. [10] pyakuryal, s. k., “control of harmonics in 6-pulse rectifiers (doctoral dissertation, university of denver),” 2013. paper title (use style: paper title) vol. 2, no. 1 | january june 2019 sjet | p-issn: 2616-7069 | e-issn: 2617-3115 | vol. 2 | no. 1 | © 2019 sukkur iba 45 stabilization of non-holonomic 03 dof hovercraft using robust rst control design ghulam e mustafa abro1, bazgha jabeen1, abdul manan1 abstract: there are several autonomous vehicles such that unmanned aerial vehicle (uav), unmanned ground vehicle (ugv) and unmanned under-water vehicle (uuv). all these vehicles are proposed earlier for several applications. researchers are still engaged in carrying out their research on hovercraft because of its hovering operation on land, water and ice. moreover, due to this operation it has been significantly used in transporting the heavy loads from one place to another. looking over its stability, power and size requirements, this paper proposes the stabilization of non-holonomic three degree of freedom (dof) hovercraft using robust regulation and pole placement (rst) control design. this paper suggests dynamic controller design to stabilize the parameters of proposed prototype model of hovercraft. this control scheme enables our prototype to execute various tasks in dull, difficult, dangerous and dirty conditions. the paper proposes the simulink based simulations to verify the results along with the validation with hardware results. keywords: non-holonomic, air cushion vehicle, dynamically controlling, rst (regulation, pole placement & tracking 1. introduction the term ‘under-actuated’ or ‘nonholonomic vehicles’ both are same and are defined as an autonomous system that have a smaller number of actuators as compared to the degree of freedom. the paper addresses the hovering state problem of non-holonomic three degree of freedom hovercraft. at this state the number of forces and all torques should converge to zero as soon as possible so that the hovercraft can continuously hover at the surface. the discussed prototype in this paper is non-holonomic in nature because it has fewer control inputs than the degree of freedom. its control inputs are thrust forces along yaw moment, surge direction while its degree of freedom is in x, y and in the mid of these axis. in the proposed non-holonomic hovercraft, the most prominent problem is to develop a particular control scheme. this scheme may be further responsible to stabilize the proposed non-holonomic hovercraft as it is not satisfying the roger brockett’s condition [1] of feedback control law that asymptotically stabilizing an equilibrium for proposed non-linear mechatronic system [2] and this is because 1 department of electronic engineering hamdard university corresponding author: mustafaabro@hamdard.edu.pk of the sway that is produced indirectly by actuators. although this is one of the problems of non-holonomic structures, one may find several control designs in order to control and stabilize the position, velocity and torque parameters of hovercraft model [3]. one may find various controller schemes so that some of them are proposed in order to analyse the driving operation of an under-actuated hovercraft on particularly trajectory [4] [5] in a smooth way using backstepping technique. moreover, some have proposed continuous time varying tracking controller for nonholonomic surface vessel [6] and some focuses on both trajectory tracking and path planning [7] in order to operate the vehicle on provided reference trajectory. after a brief study of such non-holonomic structures one may get an idea of several control designs that have been implemented on wheeled mobile robots [8]. there are various actuated systems such that under, over and fully actuated systems but underactuated systems are difficult to stabilize. in this regard several control techniques like sliding mode controller (smc) and dual proportional integral derivative (d-pid) had been proposed for controlling the two wheels of wheeled mustafa abro(et al.), stabilization of non-holonomic 03 dof hovercraft using robust rst control design (pp. 45 50) sukkur iba journal of emerging technologies sjet | volume 2 no. 1 january – june 2019 © sukkur iba university 46 mobile robots (wmr) [2]. the most popular classical method suggested for nonholonomic structures is regulation, poleplacement technique (rst) [9]. this paper proposes rst technique in order to analyse the hovering state of proposed nonholonomic hovercraft model at water and other surfaces. it is obvious that any system’s response may be affected by the external disturbances and for that purpose a nonlinear observer technique [10] can be used. this technique not only estimates the external disturbance but also provide a way to reduce the disturbance error as well [11]. furthermore, in our case these disturbances may vary frequently and are an obviously insufficient for robust stabilization. in order to reduce the effect of such disturbances one can use the estimators for dynamic coefficients (hydro-dynamic) [12] [13] using smooth projections. nowadays, researcher prefers to implement hybrid control schemes in order to minimize the cons and maximize the pros. such that fuzzy based pid schemes [14]. these hybrid schemes can guarantee the stability as well as the bounded position error [15] but one may still face the singularity issues. after brief study of different algorithms it has been concluded that the machine learning based algorithms can eliminate this problem [16]. fig. 1: hovercraft cad structure prototype and final the main focus has been set on the deployment of an electronic circuit that can drive the proposed prototype precisely [17] as shown in figure 1. moreover, in designing non-holonomic hovercraft the material of carbon fibre has been used in order to have less weight structure [18]. in all techniques proportional integral derivative (pid) is the easiest technique to implement and one may use fuzzy based pid technique to get much better results on such non-holonomic control system [19]. the proposed modelling and controlling work has been focused on hovercraft because of its significance in transporting heavy payload from one place to another by just calculating and controlling the inputs [20]. one may look for various control algorithms to stabilize any desired system but one should also look for the advantages as well as disadvantages of these techniques. discussing proportional integral derivative controller (pid), it is easy to implement and stabilize the system, whereas it may generate non-suitable settling time and may also amplify noise frequency in the proposed plant. linear quadratic regulator controller (lqr) is proposed at the times to model the system in the presence of any external noise i.e. gaussian white noise. this controller may be problematic when the dimension of the system state is larger and this problem is more difficult to solve because it is no longer separable. in addition to this, one may study sliding mode control (smc) [2] that has an ability to stabilize even a nonlinear system which cannot be stabilized by continuous state feedback laws, but the only problem with it is its implementation i.e. actuators had to cope with the high frequency control actions that could produce premature wear and tear. moreover, one also proposes the back stepping control design for autonomous vehicles because it is implemented through chain of integrators while produces some states of the system as virtual inputs even though it has no any effect on system. 2. equation of motion on a two-dimensional plane, the movement of hovercraft can be illustrated as in figure 2. the proposed model has two thrust propellers for the manveurability in 03 directions. this basically generates two forces as fx and fy along with the orientation (x, y, 𝜃) of the hovercraft. fig. 2: two-dimensional diagram for hovercraft model mustafa abro(et al.), stabilization of non-holonomic 03 dof hovercraft using robust rst control design (pp. 45 50) sukkur iba journal of emerging technologies sjet | volume 2 no. 1 january – june 2019 © sukkur iba university 47 considering the above x-y plane, forces and observing the turning effect applied to hovercraft this paper presents the major six equations as mentioned below: x = u 1.1 y=v 1.2 θ= r 1.3 whereas, their derivatives are, as mentioned below: 𝑢 = 𝐹𝑐𝑜𝑠∅𝑐𝑜𝑠𝜃−𝐹𝑠𝑖𝑛∅𝑐𝑜𝑠𝜃−𝑏𝑢 𝑚 1.4 𝑣 = 𝐹𝑐𝑜𝑠∅𝑐𝑜𝑠𝜃+𝐹𝑠𝑖𝑛∅𝑐𝑜𝑠𝜃−𝑏𝑣 𝑚 1.5 𝑟 = 𝑑𝐹𝑠𝑖𝑛∅−𝑏𝑟 𝐼 1.6 hence the state space model can been developed using these six equations as shown below: [ �̇� �̇� �̇� �̇� �̇� �̇�] = [ 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 1 0 0 0 1 −𝑏/𝑚 0 0 0 −𝑏/𝑚 0 0 0 −𝑏𝜃/𝑙 ] [ 𝑥 𝑦 𝜃 𝑢 𝑣 𝑟] + [ 0 0 0 0 0 0 1/𝑚 0 0 1/𝑚 0 𝑑/𝑙 ] [ 𝐹𝑥 𝐹𝑦 ] 1.7 c = [ 1 1 1 0 0 0] 1.8 d = [ 0 0 ] 1.9 in the above equations the u, v are the linear velocities and r as angular velocity. moreover, the bv, bu are the co-efficient of linear frictional force and br or b𝜃 is the coefficient of angular frictional force. in the state space matrix the m is the mass and l is given as the length of hovercraft respectively. 3. control design in order to get an optimal desired response from an actual response the rst controller has been proposed. it is obvious that any control system will never work for the same as it had been performing initially because of the variation in several parameters. this variation may occur due to several reasons such that temperature pressure conditions or simply by external disturbance (noise). hence, one should look forward for a control design that may work on adaptive self-tuning of control systems. this paper proposes the technique named as regulation, pole-placement and tracking (rst) control design that is nothing but the placement of poles at right location. rst or pole placement technique is the most widespread methodology used for advancing the control systems. furthermore, if someone places feed forward controller along with feedback controller in order to manipulate the input in digital domain as well as reduces the noise or external disturbance, such technique is known as rst technique. the controller is based on the resolution of a diophantine equation. in this heading, rst controller design is presented for the stabilization of non-holonomic hovercraft. since rst technique is applied on discrete model hence the state space model will be turned into z-domain using the basic mathematics. the transfer function of known system is, 2.0 whereas the desired transfer function has been illustrated as, 2.1 rst based control algorithm provides fine results in stabilization the key response such that translational and rotational movement of hovercraft. by knowing the poles and zeros from the definition of transfer function paper proposes the below calculation and proposes the diophantine equation: 𝑅𝑢(𝑡) = 𝑇𝑢𝑐(𝑡) − 𝑆𝑦(𝑡) 2.2 replacing s=t we get, 𝑢(𝑡) = 𝑇 𝑅 (𝑢𝑐(𝑡) − 𝑦(𝑡)) = 𝑇 𝑅 (𝑒(𝑡)) 2.3 equation 2.3 represents the control law for controlling the desired parameters i.e., u, v and r (translational and angular velocities). 4. simulation results beneath this heading, one may look into the simulated control algorithm for nonholonomic hovercraft model using regulation and pole placement (rst) technique as illustrated in the figure 3. mustafa abro(et al.), stabilization of non-holonomic 03 dof hovercraft using robust rst control design (pp. 45 50) sukkur iba journal of emerging technologies sjet | volume 2 no. 1 january – june 2019 © sukkur iba university 48 in the hovering state there would be two translational velocities and one rotational velocity namely u, v and r. the proposed rst control algorithm is designed to stabilize these velocities and converges it to zero state so that the hovercraft may contiuously hover on sea or any other surface. the simulation results for all velocities are shown in figure 4. moreover the torque (turning effect) produced during the rotational manevurability has been simulated at τ=0, 0.5 and 1 as illustrated in figure 5. fig. 4: hovering state velocities u, v and r of proposed hovercraft model fig. 3: close loop (rst) based control diagram fig. 5: the torque produced at different tau values mustafa abro(et al.), stabilization of non-holonomic 03 dof hovercraft using robust rst control design (pp. 45 50) sukkur iba journal of emerging technologies sjet | volume 2 no. 1 january – june 2019 © sukkur iba university 49 the feedback mechanism along with proposed control design shares the error when proposed hovercraft is powered up, it will slightly go up from the front and at that moment the pitch is produced (rotation side to side) which is soon finished when the air in plenum settles or comes at equilibrium state. moreover, rotation on vertical axis is known as yaw and this is produced when back fan along with rudder mechanism is powered up; the same settles at equilibrium state. it is noted that the rotation on front to back axis is known as roll that is not observed in this case as our acv does not go in z-axis. the eular angles such that pitch and yaw are illustrated in figure 7. being occurred while covering distance in x y and in the mid of these axis while turning as illustrated in figure 6: 5. conclusion in this paper robust rst controller is suggested to stabilize the non-holonomic 03 degree of freedom hovercraft model duly prepared in carbon fibre material. the technique not just controls the mathematically driven dynamics but also stabilizes the hovering state and three significant velocities and two euler angles too. one may get all simulations and results being linked with each other. the best feature of the paper is the implementation of the algorithm at proposed model of nonholonomic hovercraft. fig. 6: the error signal produced with respct to u, v and r velocities fig. 7: eular angles produced and simulated using simulink mustafa abro(et al.), stabilization of non-holonomic 03 dof hovercraft using robust rst control design (pp. 45 50) sukkur iba journal of emerging technologies sjet | volume 2 no. 1 january – june 2019 © sukkur iba university 50 acknowledgment while working on this non-holonomic system from the first start to its final form, there were many of my mentors who came forward and encouraged on the completion of this technical paper. it is an immense honour to acknowledge here dr. valiuddin professor at hamdard institute of engineering and technology hiet, karachi and my co-authors of this paper for their invaluable encouragement and support. whereas i am highly grateful to gulbadin khan kakar research scholar at polytechnic university milan, italy for his sincere involvement till last though he was out of country. i thank everyone once again for their kind support for bringing this piece of research to its final stage. references [1] r. w. brockett, “asymptotic stability and feedback stabilization,” in differential geometric control theory. basel, switzerland: birkhäuser verlag, 1983, pp. 181–191. [2] m. reyhanoglu, a. van der schaft, n. h. mcclamroch, and i. kolmanovsky, “dynamics and control of a class of underactuated mechanical systems,” ieee trans. autom. control, vol. 44, no. 9, pp. 1663–1671, sep. 1999. [3] i. fantoni, r. lozano, f. mazenc, and k. y. pettersen, “stabilization of a nonlinear underactuated hovercraft,” in proc. 38th conf. decis. control, 1999, pp. 2533–2538. [4] a. p. aguiar, l. cremean, and j. p. hespanha, “position tracking for a nonlinear underactuated hovercraft: controller design and experimental results,” in proc. 42nd ieee conf. decis. control, vol. 4, dec. 2003, pp. 3858–3863. [5] h. k. khalil, nonlinear systems. upper saddle river, nj, usa: prentice-hall, 2002. [6] a. behal, d. m. dawson, w. e. dixon, and y. fang, “tracking and regulation control of an underactuated surface vessel with nonintegrable dynamics,” ieee trans. autom. control, vol. 47, no. 3, pp. 495–500, mar. 2002 [7] xie, wei, david cabecinhas, rita cunha, and carlos silvestre. "robust motion control of an underactuated hovercraft." ieee transactions on control systems technology 99 (2018): 1-14. [8] a. behal, d. m. dawson, w. e. dixon, and y. fang, “tracking and regulation control of an underactuated surface vessel with nonintegrable dynamics,” ieee trans. autom. control, vol. 47, no. 3, pp. 495–500, mar. 2002 [9] j. alves et al., “vehicle and mission control of the delfim autonomous surface craft,” in proc. 14th medit. conf. control automat., jun. 2006, pp. 1–6 [10] t. i. fossen and j. p. strand, “passive nonlinear observer design for ships using lyapunov methods: full-scale experiments with a supply vessel,” automatica, vol. 35, no. 1, pp. 3–16, jan. 1999. [11] k. d. do, “practical control of underactuated ships,” ocean eng., vol. 37, no. 13, pp. 1111–1119, 2010. [12] k. d. do, z. p. jiang, and j. pan, “robust adaptive path following of underactuated ships,” automatica, vol. 40, no. 6, pp. 929–944, jun. 2004 [13] k. d. do and j. pan, “global robust adaptive path following of underactuated ships,” automatica, vol. 42, no. 10, pp. 1713–1722, 2006 [14] safwan, muhammad, vali uddin, and muhammad asif. "nonholonomic mobile robot trajectory tracking using hybrid controller." mehran university research journal of engineering & technology 35, no. 2 (2016): 161. [15] a. p. aguiar, l. cremean, and j. p. hespanha, “position tracking for a nonlinear underactuated hovercraft: controller design and experimental results,” proceedings of the ieee conference of decision and control, maui, hawaii, usa, dec. 2003, pp. 3858-3863 [16] h. sira-ramirez, “dynamic secondorder sliding mode control of the hovercraft vessel,” ieee transactions on control systems technology, vol. 10, no. 6, pp. 860-865, nov 2002. [17] monitoring at neonatal intensive care units." in applied sciences in biomedical and communication technologies, 2009. isabel 2009. 2nd international symposium on, pp. 1-6. ieee, 2009. [18] el-khatib, m. m., and w. m. hussein. "stabilization and design of a hovercraft intelligent fuzzy controller." international journal of engineering 2, no. 12 (2013) [19] ali, zain anwar, daobo wang, muhammad safwan, wanyue jiang, and muhammad shafiq. "trajectory tracking of a nonholonomic wheeleed mobile robot using hybrid controller." international journal of modeling and optimization 6, no. 3 (2016): 136 [20] “what is motion capture,” 2016. [online]. available: https://www.vicon.com/what-ismotion-capture. 2. orientation detection of unequally spaced complexed grounding grids using transient electromagnetic method vol. 4, no. 2 | july – december 2021 sjet | p-issn: 2616-7069 |e-issn: 2617-3115 | vol. 4 no. 2 july – december 2021 33 analysis of efficient fpga based pid controller for dc-dc buck boost converter using hardware cosimulation setup shafquat hussain1, waqar ahmed1, ahmed muddassir khan1 rizwan ali2 abstract: converters are widely used in smart grid applications where multilevel dc voltage sources are required in a system. the object of the paper is to design dual input dc-dc converter and implement fpga based pid controller on that converter. there are few critical challenges in existing converters: low efficiency, slow response time, large circuit size due to more number of switches, and subsequently low pwm signal quality. moreover, a separate converter is required for each source used. for the solution to this problem, a dual input dc-dc converter is proposed. in this work, we proposed and analyzed an efficient fpga based pid controller using hardware co-simulation for dc-dc buck-boost converter and compare their results. we have successfully integrated two different sources of energy, which are being fed to the power stage. the control of this converter topology is implemented by using fpga kits virtex5 and virtex7. furthermore, the efficiency of both kits is compared and analyzed. by comparison, the virtex7 has more slice register, luts, and occupied slices than virtex5. the proposed converter has high efficiency, fast response time, and compact size due to the least number of switches compared to the conventional topology of those converters. keywords: buck boost converter, fpga, pid controller 1. introduction demands for renewable energy systems are exponentially increasing day by day to cope up with the challenges of high cost, pollution, and wastage in conventional energy sources. moreover, system's flexibility, stability, and reliability can be enhanced using the integrated energy source like solar and wind. as renewable energies like solar and wind may not exist the whole day, their obtainability relies on their nature and weather conditions. if the load is supplied through multiple sources, the reliability of the system will be further improved. similarly interest in the automobile industry shifted from fuel to 1department of electrical engineering, fest, indus university, karachi, pakistan 2department of electronic engineering, ned university of engineering and technology, karachi, pakistan corresponding author: ahmed.muddassir@indus.edu.pk the electric vehicles or hybrid electrical vehicle (hev)[1-4]. there are many topologies of the converter from literature, but two main topologies are isolated and non-isolated converter topologies. in the case of isolated topologies, the single binding and multi-binding transformers have high complexity, which will reduce the converter's efficiency and compactness. the non-isolated converter topology is preferred due to cost and efficiency issues. [5-6]. there are few generalized approaches for the development of microcontroller unit (mcu) which is the heart of any converter. by taking benefit of this ability, this paper proposes the mailto:ahmed.muddassir@indus.edu.pk analysis of efficient fpga based pid controller for dc-dc buck boost converter using hardware co-simulation setup (pp. 33 39) sukkur iba journal of emerging technologies sjet | vol. 4 no. 2 july – december 2021 34 different case scenarios and system behavior, and the desired simulating parameters can be determined and (mcu) microcontroller unit [7]. a critical issue in using mcu is that there is a slow or delayed response subsequently output of converter will be effected. to resolve this issue field-programmable gate array (fpga) technology is employed which has much advanced to design intricate and fast dynamics control techniques and at the realistic operating frequency estimate the performance in the real-time foundation [8]. moreover, fpgas are flexible in implementation because desired logic is programmed through implementation the algorithms as per requirement of application and it can be esailly modified if required [910]. hence, designing the converter based on fpga, is more straightforward than modification process in mcu [11]. in fpga programming, first hardware description language (hdl) code is converted into binary after that, and it is uploaded to the fpga kit with the help of the compiler. any algorithm can be implemented on fpga by first changing hdl code to binary code and finally uploading that binary code into the fpga kit with a compiler's help. a programmer who uses the matlab program can easily convert matlab code into hdl code by using matlab. this approach produces logic faults because of its conversion to fixed data from floating-point [12]. another more efficient technique is the xilinx system generator (xsg), which consents the user to program multiple fpga devices [13]. in [14] the proposed topology has been controlled through conventional pid controller in any mcu. while in this paper pid controller is implemented in fpga which has high speed as compared to the conventional mcus. other parts of the paper are: in part 2, the working of dual input dc-dc buck-boost converter is presented. in part 3, controller implementation is shown. in part 4, there are results and discussion that show the proposed converter's simulation results, and in part 5, the conclusion, in which achievement of proposed model is discussed c7 coordinate in case of 1 st model figure 9 correlates to c3 in 2 nd model figure 10 and have almost same values of equivalent resistivity and magnetic field intensities describer earlier. c7 coordinate in 2 nd model figure 10 and 3rd model figure 11 has same results due to same configuration in case of 2nd model figure 10 currents i4 and i5 are flowing from c7 both of these currents are not similar and opposite to each other due to which some net current flows which is lesser than the current of c7 in model no 1 and has a bit lesser magnetic field intensity and a bit higher equivalent resistivity than c7 in model no 1 2. working and steady-state analysis of dual input dc-dc converter the circuit diagram of the proposed converter is shown in fig. 1. in the given topology, the switches like t1 and t2 are bidirectional conduction (b.c.) and bidirectional blocking (b.b.). the freewheeling current is provided by the diodes d1 and d2 as in fig. 2. the two energy sources are supplied to the converter, which involves two switches t3 and t4, with an inductor connected in series to eliminate the current ripples and a capacitor connected in parallel for removing voltage ripples from dual input dcdc buck-boost converter. the operation of switches t1 and t2 as on and off from which the converter can change its mode of operation. the capability of buckboost can be performed by switch t3, while the switch t4 performs the bidirectional operation. the two input dc voltage sources are v1 and v2, where v.o. and i.o. are the output voltage and load current, respectively. 2.1. steady-state analysis due to the different switching strategies of switches, various operating sequences are gained. the switching pattern will be chosen from the power utilization of sources. the methods of producing gate pulse namely; a) rising edge synchronization, analysis of efficient fpga based pid controller for dc-dc buck boost converter using hardware co-simulation setup (pp. 33 39) sukkur iba journal of emerging technologies sjet | vol. 4 no. 2 july – december 2021 35 b) falling edge synchronization and c) intermediate synchronization over a complete switching cycle, the switches will perform their duty cycle (d) mathematically 𝑡1 = (𝑑1 − 𝑑2)𝑇𝑠 (1) 𝑡2 = 𝑑12𝑇𝑠 (2) 𝑡3 = (𝑑2 − 𝑑12)𝑇𝑠 (3) 𝑡4 = (1 − 𝑑1 − 𝑑2 + 𝑑12)𝑇𝑠 (4) where, d1= duty cycle of switch t1. d2 = duty ratio of switch t2. for the generation of gate pulses, the intermediate synchronization technique is chosen and assumed that the switches are ideal and their switching losses are zero. at the same time, inductor (p.l.) and capacitor (q.c.) drops are insignificant. by selecting the appropriate value of the capacitor, the voltage across the load can be maintained. in fig.2, the power supplied by v1 source to the load for the time t1 sec. while two sources are connected in series for t2 sec. in last, both the sources are out of service for the time of t4 sec. t2 t1 t3 t4 in d u c to r v o lt a g e t t t t td1 ts (switching time) d2 d12 t1 t2 t3 t4 e2 e1 + e2 e1 -eo fig. 1: analysis of inductor voltage waveforms therefore the value of inductor voltage can be calculated when switch t1 is conducting for time duration t1 𝑒𝐿 = 𝑒1 ∗ 𝑡1 (5) during the time t2, the voltage of inductor is, existing. 𝑒𝐿 = (𝐸1 + 𝐸2) ∗ 𝑇2 (6) the value of voltage across an inductor, when t2 is on for a duration of time t3 is 𝑒𝐿 = 𝑒2 ∗ 𝑡3 (7) and, the value of 𝑒𝐿 as soon as all switches of the converter are off for a time duration of t=t4 𝑒𝐿 = (−𝐸0)𝑇𝑜𝑓𝑓 (8) according to the volt-second balance, the inductor voltage's average value should be zero in a steady-state condition. therefore, 𝐴𝑣𝑒𝑟𝑎𝑔𝑒 𝑖𝑛𝑑𝑢𝑐𝑡𝑜𝑟 𝑣𝑜𝑙𝑡𝑎𝑔𝑒 = ∫ 𝑒𝐿 𝑇𝑠 0 = 0 (9) here,𝑒𝐿 = inductor voltage t.s. = switching time 𝑇𝑆 = (𝑇𝑜𝑛 + 𝑇𝑜𝑓𝑓 ) (10) therefore, ∫ 𝑒𝐿 𝑇𝑠 0 = (𝐸1 ∗ 𝑡1) + ((𝐸1 + 𝐸2) ∗ 𝑡2) + (𝐸2 + 𝑡3 ) + (−𝐸0)𝑇𝑜𝑓𝑓 = 0 (11) the relationship between the input and output voltage equation can be obtained by solving the equation (11). 𝐸0 = 𝐸1𝑑1+𝐸2 𝑑2 (1−𝑑1−𝑑2+𝑑12) (12) where, 𝑑1 = 𝑡1+𝑡2 𝑡𝑠 , 𝑑2 = 𝑡2+𝑡3 𝑡𝑠 and 𝑑12 = 𝑡2 𝑇𝑠 the value of capacitance and inductance, which will be used as filters, can be obtained from ripple voltage (δv) of a capacitor and ripple current (δi) of the inductor, respectively. ∆𝑖 = 𝐸0(1−𝑑1−𝑑2+𝑑12) 𝐿∗𝑓𝑠 (13) ∆v = 𝐸0(𝑑1+𝑑2−𝑑12) 𝑅∗𝐶∗𝑓𝑠 (14) analysis of efficient fpga based pid controller for dc-dc buck boost converter using hardware co-simulation setup (pp. 33 39) sukkur iba journal of emerging technologies sjet | vol. 4 no. 2 july – december 2021 36 3. a system model and design of fpga based pid regulator the power stage of the converter: the two different energy sources are being fed to the dual input dc-dc buck-boost converter, which regulates the output voltage. the working of the controller: the pid controller senses the error signal and generates the control signals, and then the modulator converts control signals into pwm signal to regulate the output voltage. subtract subtract error signal compensator pwm technique s o u r c e 1 s o u r c e 2 mosfet 1 diode 1 diode 2 diode 3 c a p a c it o r r e s is t o r invert fig. 2: system model of closed-loop control of dual input dc-dc buck-boost converter. 3.1. implementation of pid controller in fpga the type of linear controller is the pid controller is straightforward and has easy mathematical modeling by comparing it with the controller of the non-linear type. pid consists of a proportional (p), integral (i), and derivative (d) controller. pid controller provides particular control action to the process by tuning these three parameters of proportional, integral, and derivative of the pid controller. there are several tuning methods of the pid controller. there are multiple tuning methods for tuning the proportional, integral, and derivative values. one of them is the trial and error method that will be used in this paper [14]. 3.1.1. hardware co-simulation before implementing the pid algorithm onto the asic, we need to verify the working functionality that is all about hardware cosimulation [14]. the xsg is the platform that receives input vectors from the matlab simulation and sends it to the fpga kit. on the other hand, it receives output vectors from fpga and sends them to matlab to perform its work and display the desired results. fig. 3: block diagram of hardware cosimulation the power stage of the dual input dc-dc converter has given feedback, which includes reference quantity, controller, and pwm strategy. the controller used is fpga-based pid, which generates a control signal which can be further converted into a pwm signal and will be sent to the switches to perform its function. the working of the whole system is shown in fig. 3. implementation of the pid controller on fpga is done by using the xsg in matlab and xilinx ise design suite platforms, which is explained in fig.04. analysis of efficient fpga based pid controller for dc-dc buck boost converter using hardware co-simulation setup (pp. 33 39) sukkur iba journal of emerging technologies sjet | vol. 4 no. 2 july – december 2021 37 fig. 4: design of pid controller using xilinx system generator 4. results and discussion the two sources are given as an input to the dual input dc-dc converter. the values for the two sources are 10v and 5v. the power stage design of this converter was explained previously. the closed-loop control is designed and simulated, followed by the pid controller as a compensator. figure no.05 circuit diagram of dual input dc-dc converter the above circuits represent dual input dc-dc buck-boost converter, which maintains the required d.c. output voltage. the above circuit represents dual input dc-dc converter feed by two sources of energy. the converter's control is being done using pid controller, which is designed by using xsg and then generating a vhdl code to download into fpgas vitex5 and virtex7 to observe the performance of these fpga kits and also verify the results using hardware cosimulation. the virtex family used in this paper is because this family has high performance and capability as compared to the spartan family fpgas. fig. 6: output voltage of dual input dcdc converter across the load after designing the power stage and control of the dual input converter, the required output dc-dc voltage is verified using hardware co-simulation, which is, in this case, is d.c. 400v. analysis of efficient fpga based pid controller for dc-dc buck boost converter using hardware co-simulation setup (pp. 33 39) sukkur iba journal of emerging technologies sjet | vol. 4 no. 2 july – december 2021 38 fig. 7: output current of dual input dcdc converter across the load the pid controller's tuning is done based on the trial and error method to set the parameters of proportional, integral, and derivative. the pid controller's accurate tuning results in the converter's exact output voltage and current across the load. 4.1. fpga resource utilization the virtex5 and virtex7 are used for the given topology of the system. the utilization of resources for virex5 and virtex7 are listed below. table.1. comparison of fpgas resource utilization r e so u r c e s virtex5 virtex7 xc.5vlx50tff1136-1 xc7vx330t2ffg1157 used avail able utili ze used availa ble utilize number of slice register s 97 12480 1% 95 408000 1% no. of slice luts 3318 12480 26% 3405 204000 1% no. of occupied slices 1048 3120 33% 1008 51000 1% as from the above table, the virtex5 has the least number of slice registers, lookup tables, and several occupied slices compared to virtex7. 4.1.1. power losses in virtex7 and virtex5 the virtex7 and virtex5 have many slice registers, luts, and occupied slices, so they are more efficient than previous fpga kits. chart 1: comparison of power losses in virtex5 and vitex7 kit total power is 1.133w, the power consumed by the dynamic and static types are 0.067w and 1.066w, respectively. total power is 1.133w, the power consumed by the dynamic and static types are 0.084w and 0.405w, respectively. the chart for the power consumption of fpga is shown in chart 1. 5. conclusion the hardware co-simulation methodology is used to test the hardware performance—the whole system's simulation and the pid controller implements in vitex5 and virtex7 fpga kits. the virtex7 has maximum losses as compared to the virtex5. the converter's complex dynamic response is successfully received by a fpga based pid controller. results also validate that the negligible losses and no delay time is also achieved in proposed fpga based pid controller, hence it is beneficial and efficient to implement a pid controller on fpga quickly. this work can be further implemented to cope up with the demands hybrid electric vehicles (hev) with efficient dual input 0 2 vitex 7 virtex 5 static vs dynamic losses static losses dynamic lossess total losses analysis of efficient fpga based pid controller for dc-dc buck boost converter using hardware co-simulation setup (pp. 33 39) sukkur iba journal of emerging technologies sjet | vol. 4 no. 2 july – december 2021 39 converter provision. moreover, the proposed converter topology has the advantage of regulating the voltage. so, this topology is also suitable for different voltage source as an input source. author contribution all authors contributed equally to the work. data availability statement not applicable conflict of interest the authors declare no conflict of interest. funding not applicable. acknowledgment not applicable. references y. liu et al."design and implementation of droop control strategy for dc microgrid based on multiple dc/dc converters," 2019 ieee innovative smart grid technologies asia (isgt asia), chengdu, china, 2019, pp. 38963901, doi: 10.1109/isgtasia.2019.8881129. lópez-santos, et al. “a unified multimode control of a dc–dc interlinking converter integrated into a hybrid microgrid.” electronics 8 (2019): 1314. a. a. s. bukhari, et al. "design of a high speed 18/12 switched reluctance motor drive with an asymmetrical bridge converter for electric vehicles," 2018 international conference on computing, mathematics and engineering technologies (icomet), sukkur, 2018, pp. 1-6, doi: 10.1109/icomet.2018.8346398. s. hussain, et al., “simulative analysis of power conversion system for hybrid electric vehicles based on dual input sources including charging from solar panel”, pakistan j engg & tech, vol. 3, no. 03, pp. 14-19, dec. 2020. lavanya, a., et al.“design of novel dual input dc–dc converter for energy harvesting system in iot sensor nodes”. wireless pers commun (2020). https://doi.org/10.1007/s11277-02007048-0. f. kardan, et al,"a new three input dc/dc converter for hybrid pv/fc/battery applications," in ieee journal of emerging and selected topics in power electronics, vol. 5, no. 4, pp. 1771-1778, dec. 2017, doi: 10.1109/jestpe.2017.2731816. khan t.h., et al., “design of a smartdevice and fpga based wireless capsule endoscopic system”. sensors and actuators a: physical, 2015. 221: p. 7787. s. j. pinto, g. panda, and r. peesapati, “an implementation of hybrid control strategy for distributed generation system interface using xilinx system generator”, ieee trans. industrial informatics, vol. 13, no. 5, october 2017 turcza, p. and m. duplaga, “energyefficient image compression algorithm for high-frame rate multi-view wireless capsule endoscopy”. journal of realtime image processing, 2016. turcza, p. and m. duplaga, “hardwareefficient low-power image processing system for wireless capsule endoscopy”, biomedical and health informatics, ieee journal of, 2013. 17(6): p. 1046-1056. a. r. yilmaz and b. erkmen, "fpgabased space vector pwm and closed loop controllers design for the z source inverter," in ieee access, vol. 7, pp. 130865-130873, 2019, doi: 10.1109/access.2019.2940670. liang, g., et al. “a hardware in the loop design methodology for fpga system and its application to complex functions”, in proceedings of technical program of 2012 vlsi design, automation and test. 2012. bhellar, s., et al., “comparative analysis of pid and fuzzy logic controller for buck converter”. ,estirj.com, 2(1), 2018, 1–6. k. varesi, et al. "performance and design analysis of an improved non-isolated multiple input buck dc–dc converter," in iet power electronics, vol. 10, no. 9, pp. 1034-1045, 28 7 2017, doi: 10.1049/iet-pel.2016.0750. format template vol. 3, no. 2 | july december 2020 sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 82 modeling and simulation of under -frequency relay for generator protection ahsan ali memon1,mohsin ali koondhar1, imdad ali memon1, munawar ayaz memon1, masood ali koondhar1, s. abid ali shah bukhari1, irfan ali channa2 abstract: power systems are undergoing structural changes induced by the combination of the operation of microgrids and distributed generation units. this transfiguration has impersonated new challenges in well-established power system practices, coordination of protection systems and especially on the design. same time, technological improvements in protective equipment have set up the basis for the development of digital frequency relays (dfl) which enable an alternate approach to standard protection schemes. it is necessary for the power system to operates, regulates and manages ancillary services more efficiently to maintain the reliability of the system. the power system is continually laying unexpected contingencies which cause inequality between load demand and generated power. such uncertainties cause the disturbance in the power system frequency. the only way to maintain power system frequency by balancing load and generation. in this paper, we have designed the under-frequency relay (ufl) model in matlab simulink. we have noticed that when the load on the system is increased, the designed model shed the extra load and are modeled through under frequency relay by comparing the frequency responses of the power system. keywords: synchronous machine; underfrequency relay; relay setting; critical load 1. introduction huge generation losses, disturbances and frequencies cause drop rapidly when the generation does not match to the load demand. reduction of large frequency, overload transmission line, and system collapse can degrade the performance of the load. stability is one of the most important issues of the power system. the basic problems of voltage, angle and frequency instability occur when there is a huge mismatch between load, and generation or n1 probability [1]. under normal operation of power system, the overall generation of power 1 quaid-e-awam university of engineering science & technology, nawabshah, pakistan 2 department of automation, beijing university chemical technology, beijing china corresponding author: ahsanmemon444@gmail.com system must meet to load demand, and loss. the rise in tripping of generation units, transmission lines and load demands can affect voltage, frequency, and may cause in disturbance and dangerous cascading effects [2, 3]. deviations of large frequency can destroy the system and load performance. turbine governor can take low-level imbalances and have possibilities of damage. however, highlevel imbalances can affect power system and reduce the speed of turbine governor to ahsan ali (et al.) modelling and simulation of under -frequency relay for generator protection (pp.82 – 89) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 83 respond falling of frequency down below the satisfactory limit [4]. de-energizing the load is very costly and dangerous as well. load shedding is a very useful scheme in an emergency to control and ensure system stability. protection scheme is used to return back the system to the normal position and stabilize the frequency of the system. therefore, extra load to be shaded through the designed scheme in an emergency to avoid the system from collapse and restore the system frequency under the limit by maintaining the balance of load and generation [5, 6]. load shedding protects the system by declining excessive voltage or frequency to balance the power system and system demand load. generally, the load shedding scheme involves shedding of predetermined load amount when the frequency drops below some thresholds and is named as under frequency load shedding (ufls). the purpose of the ufls system is to restrict very less load, and run the system smooth, quick, and safe from any abnormal condition to a normal state [1, 2]. the reduction in frequency may cause huge damage to turbines, generators, plants, and can cause their failure at low frequencies. the reason is that their auxiliaries cannot sustain it, and is unable to maintain the normal position when the frequency changes about 10 to 15% below the normal frequency. elements which are more sensitive to frequency drops are a synchronous generator, steam turbines and auxiliary services [7 9]. a synchronous generator is an important and expensive device of the power systems, and is difficult to be repaired in a short time. it must be protected from abnormal conditions, and faults like overload, unbalancing of loads, excitation losses, stator winding faults, loss of synchronism and motoring [10 12]. investigates the percentage differential and power transformer protection methods of the synchronous generator. the modern digital signal can improve the protection of the generator. ground-type faults are the most common faults in the stator winding of the synchronous machine [11, 13]. these faults can be dangerous and can occur severe damages in the generator and their cause is a reduction in the generator speed and consequently in the frequency. the reduction in the frequency of the system below a threshold limit is a signal of abnormality in the power systems [7] and shedding extra load action will be taken by the under-frequency relay. the minimum acceptable limit of the system frequency can be determined by the equipment operation. generally, in order to operate the system in a continuous mode, the steam turbine must not allow the system frequency below 47.5 hz as 50 hz is a normal system frequency. hence, the process would be easy, fast, efficient and more reliable [14]. an adaptive, conventional and intelligence type of load shedding schemes are presented in [2 9]. in this paper to overcome this problem, an effective model is simulated which is able to minimize some amount of load by shedding to maintain frequency to its limit (normal position 50hz) and system in reliable condition [4]. an under-frequency relay model is presented which checks the response of the power system and can generate a signal in case of any abnormality. if the system is running in normal operation it cannot work but in case of any abnormality in load-generation, the system response cause change to the original form and the protection system senses the abnormality and under-frequency relay operates. the abnormality of the system may be due to mismatch between load and generation, it means some extra load are connected to the system and frequency of the system cause to reduces which must be minimized to operate system in normal condition and bring frequency in normal condition, so when there is mismatch occur between load and generation an underfrequency relay is modeled which is used to cut off some extra load from the system by doing load shedding to keep power system ahsan ali (et al.) modelling and simulation of under -frequency relay for generator protection (pp.82 – 89) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 84 reliability and in normal operating. the under-frequency relay is used to detect reduction in frequency by getting signal from circuit breaker during abnormal conditions of the system and operate automatically [6]. the load must be shaded for possible maximum condition so that systems maintain its normal condition [5]. the frequency relay is settled to remove extra loads to overcome frequency thresholds at different stages [15]. the number and amount of sheds are predecided in the systems [7]. the change in frequency refers directly to deficiency of power [5, 7]. 2. system model single line to ground faults are very dangerous faults and may result in severe damage in stator core and winding [16]. single line to ground fault is most common fault of insulation failure and cause of burning of weld laminations and iron part. underfrequency relay is used to determine protection from the fault during abnormal conditions of the load to avoid from such faults [10]. and this damage of winding causes abnormality in a generator because of the increase in the load of the power system which reduces the speed of the generator which directly effects the frequency of the system. there are some tests which performed during abnormal conditions of the load when frequency varies at different rates with the help of a protective relay. a single line diagram under frequency relay for generator protection is shown in figure 1. fig. 1: modeling of under-frequency relay for generator protection ahsan ali (et al.) modelling and simulation of under -frequency relay for generator protection (pp.82 – 89) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 85 3. protection system model the frequency of the system can be measured with voltage signal of potential transformer (pt). for the measurement of frequency in graphical way of sine wave is the difference of two consecutive times (t) at zero crossing (t1 and t2) as shown in figure 2. for the measure of total time of wave form, the factor 2 is multiplied to difference of both consecutive time t1 and t2 as shown in equations below: 𝑇 = 2 × (𝑇2 − 𝑇1) (1) 𝐹𝑟𝑒𝑞𝑢𝑒𝑛𝑐𝑦 = 1 𝑇𝑖𝑚𝑒 𝑃𝑒𝑟𝑖𝑜𝑑 (𝑇) = 1 2(𝑇2−𝑇1) (2) the frequency relay works to compare the two frequencies to maintain system stability. the function of frequency relay is to trip the circuit in case of any abnormalities. this under-frequency relay system is modeled which compares two frequencies, nominal, and variable frequency due to load changes. it compares two frequencies through the generated program shown in figure 3. if the compared frequency is under limit relay cannot operate and remain in normal operating condition but if in case of any change in the load of the power system there cause a change in frequency and relay operates through a circuit breaker.in case of an abnormal condition, relay generates a signal and sends it to the circuit breaker to cut off extra load to maintain the power system to stabilize and bring frequency under the limit or original frequency (50hz). a phase lock loop (pll) is used with frequency relay and is a closed-loop control system, which detects the sinusoidal phases of three-phase signal and frequency by internal frequency oscillator as shown in figure 4. the internal frequency oscillator is controlled by the control system to maintain the phase difference 0 (zero). it converts a 3-phase i/p signal to park transformation with the help of an internal oscillator’s angular speed. it is the easiest and simplest electronic circuit that contains a phase detector in feedback and also variable frequency oscillator. fig. 3: frequency relay a variable frequency oscillator produces input signal while the phase detector gives the comparison of that generated signal to the phase of an input signal. by keeping the input phase signal and output phase signal equal it maintains the same frequencies of input, and output. consequently, when an accumulation of synchronizing signals, a pll tracks the input frequency, or it produces a frequency of multiple inputs. abc three-phase input signal is converted into dqo (park transformation) through an internal oscillator by using the angular speed. fig. 2: measuring of frequency ahsan ali (et al.) modelling and simulation of under -frequency relay for generator protection (pp.82 – 89) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 86 fig. 4: internal diagram of pll table i: relay setting 4. simulation results & discussion to test the performance of the underfrequency relay, the load variations of 5% to 20% have been added and shown in table 1. the digital under-frequency relay for the generator, protection is based on the frequency variation due to load disturbances in the power system. for this purpose, the under-frequency relay is modeled in matlab/simulink version 2017a and applied on a power system consisting of synchronous generator and load. the performance of this relay is tested at various cases of load variations. the simulation results have shown that an under-frequency relay is capable of detecting and disconnecting the overload within a shorter period of time. the relay has the ability to stabilize the power system within a specified time. under frequency relay base load shedding frequency threshold % load shed time delay load shed in mw step 1 48.7 15 % 0.2 sec 27 mw step 2 48.5 18% 0.2 sec 32w ahsan ali (et al.) modelling and simulation of under -frequency relay for generator protection (pp.82 – 89) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 87 case # 01 the system is operating at the normal condition when the load on the system is minimum of its capacity and suddenly a 27 mw load is added. and the change in frequency is observed as the load has increased, the frequency decreases to 48.7 hz. due to this under-frequency relay has detected the abnormality and disconnects the load to bring the frequency to the normal value (50 hz) at 20sec as shown in figure 5. case # 02 the system is operating at the normal condition when the load on the system is minimum of its capacity and suddenly a 32 mw load is added. the response of the underfrequency relay observed in this case, as the load has increased, the frequency decreases to 48.5 hz. the under-frequency relay has detected the abnormality and disconnects the load to bring the frequency to the normal value (50 hz) at 20sec shown in figure 6. fig. 5: under-frequency response when the load varies 15% fig. 6: under-frequency response when the load varies 18% 48.6 48.8 49 49.2 49.4 49.6 49.8 50 50.2 50.4 0 5 10 15 20 25 30 35 40 45 50 f r e q u e n c y time (s) 48.4 48.6 48.8 49 49.2 49.4 49.6 49.8 50 50.2 50.4 0 5 10 15 20 25 30 35 40 45 50 f r e q u e n c y time (s) ahsan ali (et al.) modelling and simulation of under -frequency relay for generator protection (pp.82 – 89) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 88 5. conclusion however, if there is any unbalanced between load demand and power generation, the system frequency will change and the power system becomes unstable due to these factors, the major blackout may occur in the system. in history several blackout has seen due to instability of frequency or due to unbalancing to meet the demand or removing any of generating unit due to fault occurrence n-1 after distribution of generation and islanding issues, the frequency relays have again get attention of industrialists and researchers. in order to address this issue, this research has presented a digital underfrequency relay scheme to provide efficient and reliable operation of the power system under disturbances. the digital relay has better performance as compared to electromechanical relay due to the parameters such as high speed and accuracy. digital relays are faster and more accurate than other relays. the main purpose of this work is stabilize the system by controlling the frequency of system by variations of load to the distribution side. in this regard, a synchronous generator with a load model was designed in matlab/simulink software version 2017a. the under-frequency relay for generator protection was also modeled in matlab/simulink software version 2017a. it has been observed from the simulation results that under-frequency relay successfully detects the abnormal response and quickly disconnect the additional loads in order to bring frequency back to its normal state. in future model can be modify to make system more reliable by adjusting overfrequency relay for better syste. so that system can detect both over and under frequency problem easily. references [1] m. m. aman et al., “modeling and simulation of digital negative sequence relay for unbalanced protection of generator”, ieee international power engineering and optimization conference melaka, malaysia, pp. 72-77, 2012. [2] c. s. chen, y. l. ke, and c. t. hsu, “protective relay setting of the tie line tripping and load shedding for the industrial power system”, ieee transactions on industry applications, vol. 36, no. 5, pp. 1226 1234, 2000. [3] b. khaki, and s. m. kouhsari, “proper setting of under frequency load shedding relays in industrial plants”, in 9th ieee international conference on environment and electrical engineering, pp. 198-201, 2010. [4] u. rudez, and r. mihalic, “analysis of under frequency load shedding using a frequency gradient”, ieee transactions on power delivery, vol. 26, no. 2, pp. 565-575, 2011. [5] h. bevrani, g. ledwich, and j. j. ford, “on the use of df/dt in power system emergency control”, in ieee/pes power systems conference and exposition, pp. 1-6, 2009. [6] u. k. jethwa, r. k. bansal, n. date, r. vaishnav, “comprehensive loadshedding system”, ieee transactions on, industry applications, vol. 46, no.2, pp.740,749, 2010. [7] b. delfino, s. massucco, a. morini, p. scalera, f. silvestro, “implementation and comparison of different under frequency loadshedding schemes”, power engineering society summer meeting, vol. 1, pp. 307312, 2001. [8] c. t. hsu, “cogeneration system ` design for a high-tech science-based industrial park”, ieee trans. ind. appl., vol. 39, no. 5, pp. 1486–1492, 2003. [9] c. concordia, l. h. fink, g. ponllikkas, “load shedding on an isolated system”, ieee transactions on power systems, vol. 10, no.3, pp. 1467-1472, 1995. [10] ieee std c37.102tm: ieee guide for ac generator protection; 2006. [11] de morais, adriano p., et al., “high sensitivity stator fault protection for synchronous generators: a time domain approach based on mathematical morphology”, international journal of electrical power & energy systems, 99, pp. 419-425, 2018. ahsan ali (et al.) modelling and simulation of under -frequency relay for generator protection (pp.82 – 89) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 89 [12] m. o. oliveira, a. s. bretas, g. d. ferreira, “adaptive differential protection of three-phase power transformers based on transient signal analysis”, int j electr power energy system, 57, pp. 366–374, 2014. [13] y. wang, j. zhou, g. wei, z. dong, h. chen, “stator winding single-phase grounding faults protective scheme based on discriminant analysis for powerformers with selectivity”, int j electr power energy system, 77, pp. 145–150, 2016. [14] j. r. jones, w. d. kirkland, “computer algorithm for selection of frequency relays for load shedding”, ieee computer applications in power, vol. 1, no.1, pp.21,25, 1988. [15] p. pinceti, “emergency loadshedding algorithm for large industrial plants”, control engineering practice, 10, pp. 175–181, 2002. [16] d. reimert, “protective relaying for power generation systems”, crc press taylor & francis group, 1–545, 2006. [17] p. lakra, and m. kirar, “a comparison of under frequency relay based and frequency response model based load shedding scheme”, in annual ieee india conference, pp. 1-6, 2015. comparative analyzes of antenna designs for applications in stealth technologies vol. 4, no. 2 | july – december 2021 sjet | p-issn: 2616-7069 |e-issn: 2617-3115 | vol. 4 no. 2 july – december 2021 40 comparative analyzes of antenna designs for applications in stealth technologies deedar ali jamro1, farman ali mangi1, zubeda bhatti1 israr ahmed2 abstract: in this research uwb antennas are designed, demonstrated and compared for stealth applications. many-methods are applied on designs to realize rcs reduction. the rcs has been reduced in the whole frequency band on account of size miniaturization. moreover the monostatic rcs of modified antenna has been reduced for both x and y-polarized incident waves but maximum reduction in rcs of horizontal polarized wave is more than 25dbsm at 11.8ghz. the outcomes demonstrate that the proposed design provides a good prospect for the requirement of stealth technologies. keywords: impedance matching; radar cross section reduction (rcsr); miniaturization 1. introduction antenna is an ingredient of radar system. it is a major tool to detect and locate objects. since the development of radar has been, in a variety of military and civilian system plays a vital role. in terms of civil, thunder to be used for a sort of navigation, such as terrain avoidance, air traffic control avoidance, etc; in addition, a variety of military radar platform, can carry out tasks such as detection, surveillance and attack [2]. when the enemy radar is effectively avoided, our military target battlefield viability is able to ascend and safeguard our various military missions was carried out smoothly. therefore, radar cross section and its control have a vital importance in the academic and military engineering fields from all over the world. the radar antenna is widely utilized for modern military operations. the radar acts as a dynamic measure of survival of military systems in hostilities and animosities. in low observable platforms, rcs reduction is very important subject in avoiding sensitive targets from the detection of the hostile radar. reduced radar cross section (rcs) is the most fundamental parameter in 1department of physics, shah abdul latif university, khairpur, sindh, pakistan 2department of mathematics, shah abdul latif university, khairpur, sindh, pakistan corresponding author: deedar.jamro@salu.edu.pk stealth designs of aircrafts and watercrafts [1, 2]. the detection of friendly objects by hostile radar can be lingered on and the fighting ability of hostile and inimical radar can be enfeebled. thus the competence of friendly objects can be ameliorated. the radar low observability has been usually achieved through reducing the radar cross-section (rcs). hence, the antenna scattering is analyzed carefully as it is the principal contributor to the entire rcs of stealthy technologies. antenna, being a dominant scatter can usually generate strong rcs which handicaps the antenna designs with low rcs [3, 4]. there has been a broad study on the printed uwb antennas in recent times. they are fascinating for their configuration advantages. besides this, they have tremendous application values in stealth platforms [1]. the ultra wide band antenna is a fundamental constituent in building up the uwb technology. these antennas have been opening a way to wireless communication system and radar technology [6-9]. mailto:deedar.jamro@salu.edu.pk deedar ali jamro et. al. comparative analyzes of antenna designs for applications in stealth technologies (pp. 40 46) sukkur iba journal of emerging technologies sjet | vol. 4 no. 2 july – december 2021 41 printed circular disc monopole antenna (pcdma) is realized to be good candidates for uwb applications because they are simple in geometry, easier in manufacturing. moreover they have broad band features and omni directional radiation pattern for higher frequencies and bidirectional pattern for lower frequencies. however, the metallic coverage of the portable patches is often large, which cause to enhance their rcs. the frequency band under consideration for uwb antennas is so wide; hence it is highly challenging to consider rcs reduction in the whole band [1, 10]. according to the principles of surface current distributions on the patch of the designed antenna, the metallic region of minimum current is reduced. hence, rcs of proposed design will be reduced, while its radiation performance maintained the same as the referenced design [6]. despite, in such examines the rcs reduction wasn’t achieved in entire operating frequency band. in order to overcome these limitations, a planar design with reduced rcs is presented in this paper. this proposed design is based on uwb printed circular disc monopole antenna (pcdma) to validate the efficacy of designing techniques [1]. in this study, first we have designed a referenced pcdma; secondly its circular patch has been modified in to an octagonal patch which makes the size miniaturizations as to attribute for rcs reduction. the basic equation relating to delectability and invisibility of radar targets is as follows: ( ) 4max 2 min 4 t e pga r s   = in above equation; max r is the maximum detection range, t p the radiating power, g and e a the gain and the effective area of the radiating and receiving antennas, is the rcs of the target and min s the minimum detectable signal. thus, for given radar parameters, the maximum detection range is proportional to the 4th root of the target rcs, hence in this rational we have decreased the size of radiating patch, which ultimately reduces rcs i.e. 4 max r  moreover, we did some parametric study on the simulated models. by increasing value of dielectric make s11 bad but rcs improves. the slots on the ground and octagonal radiating patch contribute in rcs reduction. afterwards, the surface current distributions of the designs were analyzed and the region of minimum current amplitude is subtracted to balance the impedance matching and reduces the rcs as well. therefore, in this rational rcs reduction of the modified antenna has been achieved. hence, the delectability of radars decreased thus makes object invisible for the hostile radar [6, 16]. moreover; two antennas are designed and demonstrated in steps to clarify the advantage of proposed antenna. 2. antenna design and rcs reduction principle this section comprises of parametric analysis to make antenna optimized for rcs reduction operations. by doing so some important parameters of suitable values are chosen for designing the prototype as to validate the fabricated model. the referenced and proposed antennas are demonstrated in this section as shown in fig.1 and fig.2. in order to present the advantages in rcsr of the modified antenna, both the antennas are taken to be of the same ground plane and substrate. antenna designing parameters focuses on the consistency in reflection coefficient and reduction in rcs of suggested model to an optimum level. these antennas are printed on fr-4 square substrate of permittivity constant ϵr = 4.6. the height of substrate is 1.6mm. the source line and the ground are printed oppositely to the substrate. the ground slots of width 3mm and length 11mm are capable of changing surface currents of the designed model in accordance with faradays laws of electromagnetic induction [12, 13]. thus the scattering field counteract because of phase reversal of 180o [6, 14]. therefore, in such a rationale, slits on the deedar ali jamro et. al. comparative analyzes of antenna designs for applications in stealth technologies (pp. 40 46) sukkur iba journal of emerging technologies sjet | vol. 4 no. 2 july – december 2021 42 ground serves as an impedance matching in an electrical devices for easy flow of current. the patch of the proposed antenna is designed as an octagon. the sides of octagonal patches are 11.48 mm in length, while the radius of circular patch of reference antenna is 15 mm. the overall, decrease in the size of radiating patch of aimed antenna has been reduced rcs to a most favorable level. the pcdma was studied in [1], as shown in fig.2. in this paper, pcdma is preferred as a referenced antenna for its balanced radiation performance and proper scattering characteristics. it is well known that the circular radiating patch leads the antenna good performance, but its large metallic area give rise a large rcs [2, 6]. in this research large area distorts the aim of stealth. in order to achieve rcs reduction, the surface current distribution of the referenced antenna was determined [1]. the radiation characteristics of the uwb antennas are based on the distribution of surface currents over the metallic patches. fig.1 shows the surface current distributions of referenced and modified antennas. the method of reducing patch coverage is different for different type of antennas. the currents are distributed unequally. while, at the centre of the patch current distributions are out of resonance so has minimum magnitude. but in this research, after examining the surface current distributions of referenced and the modified antennas, the area where current is minimum has been reduced as shown in fig. 1. despite being the area of small surface current is reduced, so the structural mode rcs will be reduced accordingly [6]. thus, the total rcs has been reduced, while the s11 parameter of the proposed design will be maintained the same [1, 6]. the assigned frequency of this prototype covers s-band (2 ghz 4 ghz) for satellite, radio and cellular phones, c-band (4 ghz 8 ghz) for satellite and microwave relay, x-band (8 ghz -12 ghz) for radar and ku-band (12 ghz-18 ghz) for satellite tv and police radar. front view back view figure 1: antenna design steps & surface current distributions (i) front view (ii) back view fig.2 fabricated proposed model 3. results and discussion the detailed discussion of the results of the both the antennas are given in this section. deedar ali jamro et. al. comparative analyzes of antenna designs for applications in stealth technologies (pp. 40 46) sukkur iba journal of emerging technologies sjet | vol. 4 no. 2 july – december 2021 43 3.1. return loss (s11): the most commonly referred parameter relating with the antenna operation is return loss [7]. the s11 diagram of refereed and aimed designs is depicted in fig.3 (a, b). the black curve shows s11 of referenced antenna, while the red curve represents s11 of octagonal patch on it. fig.3 (a) s11 comparisons of three antennas however, the simulated return loss (s11) is below -10 db which give good efficacy on the modification of designed antenna in the whole operating frequency band and depicted by red curve as shown in fig3 (a). it is clear in blue curve that at frequency of 7 ghz s11 has been improved dramatically. as the width of feed line increases antenna radiates most effectively at lower frequencies but scattering degrades for higher frequencies as depicted in fig3 (b). if width of feed line increases, the receiving and radiating power of antenna increases consequently. it has been shown that the simulated and measured s11 graphs of the modified antenna are nearly consistent. but slight incoherency in the measured return loss is reasonable, which is caused by improper welding of the wave guide port with feed line. in fig.3 (b), the return loss curves of three antennas (i, ii and iii) are contracted together as to clarify the consequence. the simulated reflection coefficient s11 of the modified design at frequency of 2.5 ghz 18 ghz with different widths of feed line is presented in fig.3. it has been observed that almost all the curves are below -10 db but the most wanted performance of design is achieved at width of 1.05mm. fig.3 (b) effect of microstrip feed line on s11 3.2. radiation pattern the radiation pattern is a graphical representation (in polar or cartesian coordinates) of the spatial distribution of radiation from an antenna as a function of angle [7]. the simulated radiation pattern of designed and reference antennas has consistency, which indicates that the alterations in geometry of designed model did not affect on the overall scattering characteristics of antenna. the radiation pattern is normal to the antenna axis across uwb frequency band and has stable omni directional behaviour. in addition to this for lower frequencies radiation pattern looks ‘8’or bi-directional. in bi-directional patches main & back loops has same radiation strength, while side lobs are negligible. if antenna radiates more in one direction then it must radiate less in other directions as to validate law of conservation of energy. at frequency of 2 ghz main lobe magnitude is 10.5dbv/m in horizontal direction and in vertical direction main lobe strength is 15.7dbv/m. while at frequency of 4 ghz the radiation intensity has magnitude of 14.4 db v/m and in vertical direction it is 15.1dbv/m. the modified antenna looks planar monopole [7, 15]. the radiation behaviour of the designed antenna was measured in the far filed an echoic chamber with satimo at star lab 6e in uestc as shown in fig.5.afterwards, the radiation pattern is depicted and contracted at deedar ali jamro et. al. comparative analyzes of antenna designs for applications in stealth technologies (pp. 40 46) sukkur iba journal of emerging technologies sjet | vol. 4 no. 2 july – december 2021 44 θ = 900 in xy-plane, see fig7. the simulated and measured radiation pattern has slight incoherency due to some distortions on the measured curves caused by the feed connector. even then, their software results show that the radiation representations of both models are nearly identical. fig.4. designed antenna radiates in echoic chamber -50 -40 -30 -20 -10 0 0 60 120 180 240 300 -50 -40 -30 -20 -10 0 co-pol meas cr-pol meas co-pol sim cr-pol sim (a) -50 -40 -30 -20 -10 0 0 60 120 180 240 300 -50 -40 -30 -20 -10 0 cr-pol sim co-pol sim co-pol meas cr-pol meas (b) fig.5. sim: & meas co-pol and cross pol: radiation representation of cited antenna at θ= 90o in xy-plane for frequencies (a) 2 ghz (b) 4 ghz 4. rcs rcs is a measure of how target is able of being detected by radar antenna. to find a low rcs antenna, the effect of different radiating elements was analyzed by using cst microwave simulator. the feed termination has vital importance in studying the rcs reduction because it controls the scattering characteristics of antenna [1, 17].the linearly polarized monostatic rcs values of antenna connected with matched load of 50ω were studied [7]. it has been observed that the octagonal patch with octagon aperture has optimal performance and improved rcs due to its small radiating elements [11]. hereby, the rcs of modified antenna is reduced due to the reduction in structural mode rcs [3, 6]. hence, octagon patch is used as radiating element in this prototype. moreover, the antennas are terminated with short-circuit load and open circuit load then rcs curves are calculated and compared as expressed in fig.6 [1]. compared with the cited patch, the aimed design has merits on the rcs reduction in the whole operating frequency band [12, 20]. fig.6 variation of rcs values verses frequency in the proposed antenna in this part the polarization of incident field; whether parallel or perpendicular to the micro strip feed lines have been specified. the rcs of proposed antenna is simulated for both polarizations and their reductions are shown for both over the entire band. the incident and received electric fields are parallel to x –axis. the monostatic rcs of proposed model for both x and y -polarized incident and received waves are depicted over the entire frequency band as shown in fig.7 however, compared with the planar octagonal-shaped uwb deedar ali jamro et. al. comparative analyzes of antenna designs for applications in stealth technologies (pp. 40 46) sukkur iba journal of emerging technologies sjet | vol. 4 no. 2 july – december 2021 45 antenna see fig.17 and fig.18 in [17,19]; the modified design has rewards on rcs reduction in the operating frequency band. in addition, the rcs has been reduced more than 25dbsm at frequency of 11.8 ghz in the modified design as shown in fig.7 fig.7. monostatic rcs of proposed antenna for x & y-polarized waves in the second case the antennas are terminated with short-circuit load (port is connected with ground plane pec) and open circuit load (port is not connected) then rcs curves are calculated as shown in fig.7. however, compared with the referenced patch in [1], the modified design has advantages on the rcs reduction over whole frequency band. 5. conclusion in this study antennas are designed for rcs reduction in stealth technology. the s11 less than -10 db of the designed model have been accomplished in the operational frequencies ranges from 2 ghz to 18 ghz. the results show that the return loss s11 of referenced and suggested antennas is almost the same. moreover, the simulated radiation performance of both the antennas is nearly consistent and stable. the fabricated antenna has lower rcs than the referenced patches in the entire operational frequency bandwidth which is favorable for the prototype. the optimized outcomes have been supported through fabricated model and found coherency in the antenna parameters. the novelty of the design is that the rcs has been reduced in the whole operating frequency band. hence, the proposed design can be used as a uwb antenna for the necessity and control of rcs in stealth technologies author contribution all the authors contributed equally in various sections of the research paper. data availabilty statement data generated during the current study are available from the corresponding author on reasonable request. conflict of interest authors of this paper declare no conflict of interest. funding the paper is composed of simulation and fabrication results but not funded by any organization or institution. acknowledgment this work was acknowledged by the department of physics, shah abdul latif university khairpur. references t. hong, s. -x. gong, w. jiang, y.-x. xu, and x. wang, “a novel ultra-wide band antenna with reduced radar cross section”. progress in electromagnetics research, pier 96, 299–308, 2009 h. oraizi and a. abdolali, “ultra wideband rcs optimization of multi layered cylindrical structures for arbitrarily polarized incident plane waves,” progr. electromagn. res. vol. 78, pp. 129–157, 2008. wen jiang, ying liu, shuxi gong, and tao hong“application of bionics in antenna radar cross section reduction”. ieee applied wireless and propagation letters, vol. 8, 2009 127 wen jiang*, yang zhang, zhao-bin deng and tao hong“novel technique for rcs reduction of circularly polarized micro strip antennas”. journal of deedar ali jamro et. al. comparative analyzes of antenna designs for applications in stealth technologies (pp. 40 46) sukkur iba journal of emerging technologies sjet | vol. 4 no. 2 july – december 2021 46 electromagnetic waves and applications, 2013 vol. 27, no. 9, 1077– 1088 s.-c. zhao, b.-z. wang and q.-q. he“broad band radar cross section reduction of a rectangular patch antenna”, progress in electromagnetics research, pier 79, 263–275, 2008 w. jiang, t. hong, y. liu, s.-x. gong, y. guan, and s. cui, “a novel technique for radar cross section reduction of printed antennas”. j. of electromagn. waves and appl., vol. 24, 51–60, 2010 jamro, deedar ali , jing –song hong, mamadou hady bah, altaf hussain bhatti and riaz ahmed shaikh“design of monopole antenna for rcs reduction applications” 2015 ieee international conference on communication software and networks (iccsn), 2015 hai-yang xu, hou zhang, gui-yuan li, qi-bo xu, etc. “an ultra-wideband fractal slot antenna with low backscattering cross section,” microwave and technology letters, vol. 53, no. 5, 1150 1154, 2011. hai-yang xu, hou zhang, ke lu and xian-feng zeng, “a holly-leaf-shaped monopole antenna with low rcs for uwb application,” progress in electromagnetics research, vol. 117, 35̢50 2011. sci jiang wen, gong shu-xi, hong tao, wang xing, “fan-shaped antenna with low rcs for ultra wideband application,” acta electronica sinica, vol. 38, no. 9, 2162-2165, 2010 xu, haiyang, hou zhang, xianfeng zeng, and huiyong han, "novel monopole antenna with low rcs for uwb application", 2012 international conference on microwave and millimeter wave technology (icmmt), 2012. jamro, deedar ali, jing-song hong, mamadou hady bah, and farman ali mangi, "novel triangular patch antenna with reduced radar cross section", 2014 11th international computer conference on wavelet active media technology and information processing (iccwamtip), 2014. x.-f. li, y.-j. xie, and r. yang, “bistatic rcs prediction complex targets using modified current marching technique,” progr. electromagn. res. vol. 93, pp. 13– 28, 2009. hu s, chen h, and law c l, “backscattering cross section of ultrawideband antennas,” ieee antennas and wireless propagation letter, vol. 6, 70– 73, 2007 liu, ying, yuwen hao, kun li, and shuxi gong, "radar cross section reduction of a microstrip antenna based on polarization conversion meta material", ieee antennas and wireless propagation letters, 2015. deedar ali jamro ,jing-song hong, mamadou hady bah, farman ali mangi and imran memon, "triangular antenna with novel techniques for rcs reduction applications", lecture notes in electrical engineering, 2016. cengizhan m. dikmen, sibel çimen, and gonca çakır “planar octagonal-shaped uwb antenna with reduced radar cross section”, ieee transaction on antennas and propagation, vol. 62, no. 6, june 2014. b. i. wu, w. wang, j. pacheco, x. chen, t. grzegorczyk and j. a. kong, “a study of using metamaterials as antenna substrate to enhance gain,” progress in electromagnetics research, vol. 51, pp. 295–328, 2005 shaeffer, tuley and knott. radar cross section [m]. scitech publishing, 2004 w. jiang, t. hong, y. liu et al. a novel technique for radar cross section reduction of printed antennas[j]. journal of electromagn. waves and appl., 2010, 24: 51-60 vol. 5, no. 2 | july december 2022 sjet | p-issn: 2616-7069 | e-issn: 2617-3115 | vol. 5 no. 2 july – december 2022 1 modeling of ieee 9-bus system with load flow and short circuit analyses rehan ali1, abdul saboor gul1, ramez akbar talani2 abstract: load flow and short circuit analyses have been performed on standard ieee 9-bus system. this paper is going to describe in detail how these analyses were performed and what results were achieved. in addition to the performance of these two analyses on the standard test system, they were also performed by removing a voltagecontrolled generator from the test system. it is revealed that by removal of a generator, the magnitude of shortcircuit fault current in a system would reduce as compared to the case where all generators were present in the system. keywords: ieee 9bus system, load flow analysis, short circuit (sc) analysis 1. introduction before installing a power system in the real world, many tests and analyses are digitally performed on computer simulations in order to determine the exact requirements and necessary precautions for the installation of the actual system. as we know that within power systems, electric power flows from the point of generation to the required destination via different paths of network. this flow comprises of reactive and active power known as load flow. it is very important to investigate this load flow so as to plan and determine the steady operation of system. such investigations employs systematic analytical approaches so as to examine the different voltages on bus, phase angle, as well as reactive and active power that is flowing within various branches of load such as generators and transformers when steady state is attained. the important knowledge gained from such analysis gives the absolute values as well as phase angles of load bus voltage reactive 1 department of electrical engineering, ned university of engineering and technology, karachi, pakistan 2 faculty of electrical engineering, quest, pakistan corresponding author: rahimoon2223@gmail.com powers and voltage phase angles at generator buses, real and reactive power flows on transmission lines together with power at the reference bus. in addition to analytical techniques, numerical methods are also employed to solve load flow equations, as they become nonlinear and requires solution by method of iteration. however, such numerical solutions mostly provide only approximate solution. for more than thirty years different numerical investigations have been carried out to analyze power flow problems. out of them widely used methods are fast decoupled methods the gauss-seidel and newtonraphson and [1-4]. moreover, due to sudden and mammoth developments in industry the society requires electric systems which keep on enhancing in size and complexity. in such systems the power flow equations range to several thousand with such magnitude of equations it is not feasible for any numerical technique to provide solution which converges. such mailto:rahimoon2223@gmail.com modeling of ieee 9-bus system with load flow and short circuit analyses (pp. 01 09) sukkur iba journal of emerging technologies sjet | vol. 5 no. 2 july – december 2022 2 difficulty compels electrical engineers to resort to more suitable and reliable techniques. hence the issue is that industry is looking for technique that is more feasible for the analysis of power systems analytical calculations are appropriate when estimation of characteristics of smaller magnitude of circuits is being carried out, however for the more precise and accurate analysis it is imperative to employ specialized programs. digital computers are being used in calculation s of power flow equations since 1950s. with the rapid advancement in computing power all sort of load flow studies can now be conveniently carried out. load flow analysis is one of such analyses. it is important for planning, economic scheduling, operation, and the distribution of power between different sources. it is also required for many other analyses such as transient stability and contingency studies. this analysis is also required to determine the effects of new loads and new generating stations on the power system, so that the system can be extended. this analysis involves finding voltages, currents, real and reactive power flows at different points in a power system under normal/steady-state conditions. [2, 3] short-circuit analysis is mainly required for the protection of the power system and its equipment sizing. it is performed on different buses under faulty conditions which can cause a short-circuit in the system. it involves finding the huge shortcircuit current that flows in the system in the event of a fault. this analysis is also a major part of the system’s protection coordination study, which involves the sizing and placement of protective equipment (fuses, circuit breakers, etc.) in the system, in order to protect the system. [4-6]. 1.1. bus classification any node where more than one component like electric generators and transmission lines are connected is known as bus. in electrical engineering the bus is concerned with four quantities which include potential difference and its phase angle, active and reactive power. [11,12]. out of them 02 quantities are already known whereas remaining two has to be determined via solution of equation [13]. 1.2. slack bus the slack bus is a sort of reference bus used to satisfy the condition of power balance. it is mostly concerned with generation unit which is adjusted to employ the power balance condition [12]. 1.3. generator (pv) bus generator bus is essentially concerned with the voltage control. it is connected with generating unit where power generated from the bus is controlled with the help of prime mover. whereas the control over voltage so produced is made by varying the generator excitation. mostly the limits are set for reactive power and it depends on the specifications of machine used. 1.4. load (pq) bus the load bus is not due to generator but we can obtain this from old data, measurements or from forecast. in this case real power provided to the system is taken as positive, whereas the electric power utilized within system is taken as negative. in this bus p and q are known variable while |v| and δ are unknown variables. [8, 12]. 1.5. power flow analysis methods from this analysis we mean investigation of various variables of electrical system such as voltage, current, active power etc at various points in a system, once the system has attained steady state.this is carried out by solving simultaneous equations. these solutions form the platform for solving equations for performance of power system [4] 1.6. gauss-seidel method this method is developed based on the gauss method. it is an iterative method used for solving set of nonlinear algebraic equations [14]. the method makes use of an initial guess for value of voltage, to obtain a modeling of ieee 9-bus system with load flow and short circuit analyses (pp. 01 09) sukkur iba journal of emerging technologies sjet | vol. 5 no. 2 july – december 2022 3 calculated value of a particular variable. the initial guess value is replaced by a calculated value. the process is then repeated until the iteration solution converges. the convergence is quite sensitive to the starting values assumed. but this method suffers from poor convergence characteristics [15]. 1.7. fast decoupled method this method is considered as speedy and efficient for obtaining the solutions of problems pertaining to power flow. this method is basically an extension of newtonraphson method. this method was first presented in 1974 by stott and alsac in 1974 [16-18]. since this method is based on newton-raphson method so it provides much simplification in carrying out calculations, also reliable results can be obtained, rapid convergence and this method soon became mostly employed method in power flow problems. in this method polar coordinates and some approximations are used so fast algorithms for power solutions are obtained. however, the use of certain approximations also results in non-convergence in some cases. for instance, in case of large resistance-to-reactance ratios as well as for the case where low voltages appears at some buses. in such cases the solutions do not converge nicely due to approximations, so one has to resort some assumptions so as to simplify jacobian matrix. to overcome these difficulties arising due to non convergence of solutions various investigations have been carried out. for instance one of them is co nconvergence of systems with high r/x ratios, and others with low voltage buses. 1.8. newton-raphson method sir isaac newton and raphson formulated this method so it is named after them. this method employs an iterative method. by using this method we can approximate non linear simultaneous equation into linear ones with the use taylor series. however, taylor series is expanded to the first order approximations only. this numerical technique is widely used in the calculation of power flow due to its powerful convergence characteristics as compared with similar techniques. fig. 1. ieee 9-bus system modeling of ieee 9-bus system with load flow and short circuit analyses (pp. 01 09) sukkur iba journal of emerging technologies sjet | vol. 5 no. 2 july – december 2022 4 2. methodology for this study, etap software has been used. the load flow and short circuit analyses are first performed on the standard ieee 9-bus system, and their results are recorded. the load flow has been evaluated by the software using newtonraphson iterative method. after this, one generator has been removed from this test system and the above mentioned two analyses are performed again. the results of these analyses on this new system are recorded and then compared with the results obtained from the standard system. 3. test system details the test system for this study was the ieee 9-bus system. the sld of this system is shown in figure-1. the system comprises of 3 generators, connected to 3 generator buses. these are buses 1, 2 and 3 respectively. after this, we have 3 step-up transformers, one after each generator bus, which step up the voltage to the transmission level. these transformers are connected to buses 4, 7 and 9 respectively. these buses are further connected to 3 load buses, namely buses 5, 6 and 8. the system has 1 swing generator operating at a voltage of 1.04p.u. and 2 voltage-controlled generators operating at a voltage of 1.025p.u. the system consists of 3 load buses interconnected through 6 transmission lines. the transmission lines are modeled with vertical configuration of conductors and a conductor spacing of 10ft, with a single ground wire. gymnastic conductor is used. the loads are modeled with a requirement of 230kv and varying real and reactive powers. also, circuit breakers are connected on each end of the transmission lines and generator buses for protection from overloading or faults. the load flow and short circuit analyses are performed on this standard system first. after this, generator 3 is removed from the system, and then the above 2 analyses are repeated for this modified system and the results are compared. 4. simulation and discussion in this section, we will describe the simulations performed in this study and discuss their results. 4.1. load flow analysis on standard ieee 9-bus system fig. 2. load flow report of ieee 9-bus system modeling of ieee 9-bus system with load flow and short circuit analyses (pp. 01 09) sukkur iba journal of emerging technologies sjet | vol. 5 no. 2 july – december 2022 5 as we have studied theoretically, the real power flows when there is a difference between the magnitudes of voltages between 2 buses, and reactive power flows when there is a difference between the voltage phase angles of 2 buses. this is proven here in the simulation as well, as we can see figure-2. 4.2. short circuit analysis on standard ieee 9-bus system whenever a short-circuit fault occurs, it has 2 components: ac component and dc component. the ac component has further 3 stages; sub transient, transient and steady state. at the instance of fault occurrence, the sub transient current exists. it has the highest magnitude and the shortest time duration (0.5 cycles). 4.2.1. sub-transient sub transient current rapidly decreases to the transient stage. it is relatively longer (from 1.5 cycles to 4 cycles approx.). this transient current further reduces to the steady-state value, which occurs after about 30 cycles, and its magnitude is sustained throughout the rest of the fault. as shown in figure 3. note: the steady-state current mentioned in figure is still the fault current, as its magnitude is still many times greater than the nominal current. fig. 3. short circuit fault sub-transient component in the above-mentioned results, we can see the sub transient magnitudes of symmetrical and unsymmetrical fault currents (in ka) which flow through the 3 generator buses in the event of a fault. the current is highest during this stage as the generator’s impedance is lowest here. 4.2.2. transient fig. 4. short circuit fault transient component comparing the results of the sub transient and transient fault currents, we see that both of these are identical. this is due to the fact that etap calculates both these currents using the sub transient impedance values, but in reality, the impedances of both these currents are different, and therefore, there magnitudes are different as well. as shown in figure 4 this space is intentionally left blank to adjust the figers modeling of ieee 9-bus system with load flow and short circuit analyses (pp. 01 09) sukkur iba journal of emerging technologies sjet | vol. 5 no. 2 july – december 2022 6 4.2.3. steady-state fig. 5. short circuit fault steady state component comparing the steady-state current values with the sub transient and transient current values, we can see that its magnitude is lower than the other two fault currents. this is because the impedance of the generator during the steady-state stage becomes equal to the synchronous reactance. the fault current will not decrease any further than this value. load flow analysis on standard ieee 9-bus system after removing one pv generator. as shown in figure 5. the voltage-controlled generator maintains the voltage throughout the system. removing it causes a voltage drop at all the buses (except the generator buses). the load supplied by this generator is now being fed by the remaining 2 generators. therefore, the power flow at the remaining 2 generator buses increases. 4.3. short circuit analysis on standard ieee 9-bus system after removing one pv generator the short-circuit analysis is repeated after removing one of the pv generators. we see that the magnitude of the overall fault current reduces, when compared to the original test system’s fault current. this is due to the obvious fact that now there is one less generator to feed the fault. shown in figure 6. fig. 6. short circuit analysis after removing one pv generator 4.3.1. sub-transient when compared to the original test system’s fault current. this is due to the obvious fact that now there is one less generator to feed the fault. as shown in figure 7. modeling of ieee 9-bus system with load flow and short circuit analyses (pp. 01 09) sukkur iba journal of emerging technologies sjet | vol. 5 no. 2 july – december 2022 7 fig. 7. short circuit fault sub-transient component after removing one pv generator 4.3.2. transient short circuit analysis of transient component on a 9-bus system after removing one generator is shown in figure 8. fig. 8. short circuit fault transient component after removing one pv generator 4.3.3. steady-state short circuit analysis of the steady state component on a 9-bus system after removal of a single generator is shown in figure 9. fig. 9. short circuit fault steady-state component after removing one pv generator 4.4. comparison of the system before and after removing the pv bus 4.4.1. load flow comparison table i. load flow comparison before and after removing pv bus before removing pv bus after removing pv bus *voltage magnitude at bus 1 104% 104% *voltage magnitude at bus 2 102.5% 102.5% *voltage magnitude at bus 3 102.5% voltage magnitude at bus 4 100.534% 99.480% voltage magnitude at bus 5 100.523% 99.468% voltage magnitude at bus 6 100.527% 99.467% voltage magnitude at bus 7 100.530% 99.475% voltage magnitude at bus 8 100.524% 99.464% modeling of ieee 9-bus system with load flow and short circuit analyses (pp. 01 09) sukkur iba journal of emerging technologies sjet | vol. 5 no. 2 july – december 2022 8 voltage magnitude at bus 9 100.531% 99.465% here we can see that after removing the pv generator from bus 3, the voltages at all the buses (except the generator buses) drop, as has been discussed above. shown in table-i 4.4.2. short circuit comparison: note: the steady-state fault currents in the table ii below are 3-phase fault currents. the results will remain same for other types of faults. shown in table-ii table ii. short circuit comparison before and after removing pv bus before removing pv bus after removing pv bus *steady-state current at bus 1 44.518ka 37.872ka *steady-state current at bus 2 39.933ka 34.227ka *steady-state current at bus 3 45.153ka here we can see that the fault current reduces after removing a pv generator from the system, as there is one less generator to feed the fault here, as has been discussed above as well. 5. conclusion in this paper a numerical study has been carried out for load flow and short circuit analysis on standard ieee 9-bus system. from the above study we conclude that, by removal of a voltage-controlled generator from our system, the magnitude and phase angles of voltages will reduce for all the buses other than the remaining generator buses. since this was a particularly small test system, the voltage drop was minimum and did not affect the system greatly. but, had it been a large practical system, then such a removal of a voltage-controlled generator would have damaging effects on the transmission system and can also damage the connected loads due to under-voltage. moreover, it is also found that by removal of a generator, the magnitude of shortcircuit fault current in a system would reduce as compared to the case where all generators were present in the system. references [1] mageshvaran, r., raglend, i.j., yuvaraj, v., rizwankhan, p.g., vijayakumar, t. and sudheera (2008) implementation of nontraditional optimization techniques (pso, cpso, hde) for the optimal load flow solution. tencon20082008 ieee region 10 conference, 19-21 november 2008. [2] elgerd, o.l. (2012) electric energy systems theory: an introduction. 2nd edition, mcgraw-hill. [3] kothari, i.j. and nagrath, d.p. (2007) modern power system analysis. 3rd edition, new york. [4] keyhani, a., abur, a. and hao, s. (1989) evaluation of power flow techniques for personal computers. ieee transactions on power systems, 4, 817-826. [5] hale, h.w. and goodrich, r.w. (1959) digital computation or power flow—some new aspects. power apparatus and systems, part iii. transactions of the american institute of electrical engineers, 78, 919-923. [6] sato, n. and tinney, w.f. (1963) techniques for exploiting the sparsity or the network admittance matrix. ieee transactions on power apparatus and systems, 82, 944-950. [7] aroop, b., satyajit, b. and sanjib, h. (2014) power flow analysis on ieee 57 bus system using mathlab. international journal of engineering research & technology (ijert), 3. [8] milano, f. (2009) continuous newton’s method for power flow analysis. ieee transactions on power systems, 24,50-57. [9] grainger, j.j. and stevenson, w.d. (1994) power system analysis. mcgraw-hill, new york. [10] tinney, w.f. and hart, c.e. (1967) power flow solution by newton’s method. ieee transactions on power apparatus and systems, pas-86, 1449-1460. [11] bhakti, n. and rajani, n. (2014) steady state analysis of ieee-6 bus system using psat power tool box. international journal of engineering science and innovation technology (ijesit), 3. [12] hadi, s. (2010) power system analysis. 3rd edition, psa publishing, north york. [13] kabisama, h.w. electrical power engineering. mcgraw-hill, new york. [14] gilbert, g.m., bouchard, d.e. and chikhani, a.y. (1998) a comparison of load flow analysis using dist flow, gauss-seidel, and optimal load flow algorithms. proceedings of the ieee canadian conference on electrical and computer engineering, waterloo, ontario, 24-28 may 1998, 850-853. [15] glover, j.d. and sarma, m.s. (2002) power system analysis and design. 3rd edition, brooks/cole, pacific grove. [16] stott, b. and alsac, o. (1974) fast decoupled load flow. ieee transactions on power apparatus and systems, pas-93, 859-869. modeling of ieee 9-bus system with load flow and short circuit analyses (pp. 01 09) sukkur iba journal of emerging technologies sjet | vol. 5 no. 2 july – december 2022 9 [17] stott, b. (1974) review of load-flow calculation methods. proceedings of the ieee, 62, 916-929. adejumobi, i.a., et al. (2014) numerical methods in load flow analysis: an application to nigeria grid system. international journal of electrical and electronics engineering. vol. 5, no. 2 | july december 2022 sjet | p-issn: 2616-7069 | e-issn: 2617-3115 | vol. 5 no. 2 july – december 2022 49 efficient detection and recognition of traffic lights for autonomous vehicles using cnn tayyaba sahar1*, hayl khadhami2, muhammad rauf1 abstract: smart city infrastructure and intelligent transportation systems (its) need modern traffic monitoring and driver assistance systems such as autonomous traffic signal detection. its is a dominant research area among several fields in the domain of artificial intelligence. traffic signal detection is a key module of autonomous vehicles where accuracy and inference time are amongst the most significant parameters. in this regard, this study aims to detect traffic signals focusing to enhance accuracy and real-time performance. the results and discussion enclose a comparative performance of a cnn-based algorithm yolo v3 and a handcrafted technique that gives insight for enhanced detection and inference in day and night light. it is important to consider that real-world objects are associated with complex backgrounds, occlusion, climate conditions, and light exposure that deteriorate the performance of sensitive intelligent applications. this study provides a direction to propose a hybrid technique for traffic light detection (tld) in the daytime and at night. the experimental results successfully improve the night-time detection accuracy of traffic lights from 71.84% to 79.51%. keywords: object detection; convolutional neural networks; you only look once; intelligent transportation systems; hough transform; traffic signal lights 1. introduction humans have eyes and brains that signify their natural ability to detect and classify objects around them. their detection and recognition capabilities are uncompilable to artificially intelligent systems. recent progressions prompting upgrades in proficiency and execution in this field would ease human existence by facilitating them through intelligent systems. similarly, the provision of convenient applications for drivers and road safety is crucial for intelligent transportation systems (its). it aims to modernize the operation of vehicles and promotes driver-assisted systems and driverless cars. traffic light detection in realtime is challenging since it is associated with real-world problems. this includes complex 1department of electronic engineering, dawood university of engineering & technology, karachi, pakistan 2department of industrial engineering and management. dawood university of engineering & technology, karachi, pakistan corresponding author: sahartayyaba@gmail.com backgrounds, occlusion, climate conditions, and light exposure that depreciates the performance of sensitive intelligent applications. the efficiency of its is crucial, whereas less efficiency is reported due to the variation of light exposures specifically day and night light. the motivation for this study is inspired by some real-life problems associated with tld. problems such as biasness between traffic lights and signs, and variations in day and night light recognition efficiency. therefore, different experiments and techniques are needed to be tested to enhance the detection accuracy of traffic lights in day and night light. mailto:sahartayyaba@gmail.com efficient detection and recognition of traffic lights for autonomous vehicles using cnn (pp. 49 56) sukkur iba journal of emerging technologies sjet | vol. 5 no. 2 july – december 2022 50 the development of its has evolved in two stages: data acquisition and processing followed by the development of technologies for vehicle safety such as collision detection and avoidance [1]. these systems are important for urban planning and future smart cities, because of transportation and transit efficiency [2,3]. tls is a salient module in driver assistance systems (das) and autonomous vehicles [4]. the placement of cameras, the distance of objects, light exposure, and the processing ability of vehicular chips affect the traditional computer vision-based systems used for tld [4-6]. deep learning-based cnn models have been deployed in numerous applications after the achievement of incredible results of alex net [7]. you only look once (yolo) version 3 is a 106-layer [8] fully convolutional underlying architecture that is a variant of the original darknet which comprises 53 layers of a network trained on imagenet. experimental studies reveal that compared to other deep learning models yolov3 is a faster, stronger, and more reliable real-time object detector [9]. for automated vehicles, timely detection of traffic lights and their changing states is very important whereas yolo does generalize object representation without precision losses than other models [10]. a single neural network predicts the boundary boxes and class possibilities from an image of the video frame in a single evaluation. usually, traffic signs and lights are placed together, these images appear relatively smaller in road view images. thus, true recognition and detection become challenging as it covers only 1%-2% of the total image area [11]. the combination of cnn and handcrafted techniques is applied to determine the best input features [12]. well-acknowledged pattern analysis tools such as hough transform (ht) result in realistic outcomes against distortion and diffraction. on the other hand, high material needs and computation costs are two disadvantages that come with it [13]. the latest research and advancements in the field of ml enable to combine the different algorithms from similar or different domains to complement each other [14]. throughout the years, an increment in the number of cars on roads has increased the frequency of causalities. this endangers human life and safety therefore computer vision techniques are needed to be utilized for observing the immediate data in real-time [15]. existing studies reveal various intrusive and non-intrusive such as in situ techniques and invehicle technologies that are used for traffic monitoring. computer vision-based techniques have shown better performance than traditional ones [16]. vitas et al. proposed a hybrid model for the traffic light recognition system using adaptive thresholding and deep learning for region proposal and localization of traffic lights [17]. the researchers used an open-source lisa dataset and custom augmentation to increase the number of data samples. on the other hand, the classification part of the algorithm gave off an 89.60% true detection rate, while the regression correctly localized 92.67% of the traffic lights [17]. tld is challenging due to the small size and colors that may be similar to the backgrounds. faster region-based convolutional neural networks (r-cnn) and grassmann manifold learning have a high degree of accuracy and are robust [18]. comparative studies of several state-of-the-art methods show that variations and cascaded detection techniques help to deal with real-life issues that affect the detection process [18, 19]. moreover, other kinds of traffic lights including traffic signs and pedestrian lights have been identified as the main cause of false positives. deep convolutional tld shows an overall detection performance of 0.92 average precision of traffic lights [19]. the brief analysis of the state-of-the-art reveals that tld using color space and shape detection is dominant for finding the exact parameters of traffic lights [20].in this paper, we propose a framework for efficient tld using deep learning and hand-crafted technique to monitor the day and night time efficiency. moreover, the core contributions of the paper include proposing a framework for the hybrid technique for tld. the foremost target is to improve the night light efficiency of the algorithm. whereas, it also emphasizes the efficient detection and recognition of traffic lights for autonomous vehicles using cnn (pp. 49 56) sukkur iba journal of emerging technologies sjet | vol. 5 no. 2 july – december 2022 51 availability of the dataset having an equal proportion of day and night light images for accurate training. in addition, a subset of this type of dataset has been prepared for conducting this experiment. this technique is practically implementable using real-sense cameras having day and night vision capabilities mounted behind the windshield of autonomous vehicles. enhanced real-time detection and recognition of traffic lights will help to cope with the increasing rate of road accidents and causalities. the research is organized in sections as follows: the introduction outlines the background, motivation, brief review of the state-of-the-art, contribution, and application of this technique. the subsequent sections of this paper include methods and then the experimental results for the applied methodology. the last section concludes the research outcomes. 2. method this paper outlines an efficient tld technique to strike a balance between recognition accuracy and overall model complexity. this experimental study aims to propose a hybrid technique that has been summarized in fig. 1 & 2. with the proposed method tld accuracy in different lightening conditions can be detected through three major stages: image preprocessing, feature extraction, and image identification. fig. 1. traffic light detection using yolo v3 fig. 2. traffic light detection using hybrid method fig. 3. yolo network architecture [23] input image or video frames random patches cnn feature extraction output input image or video frames random patches cnn feature extraction shape detection enhanced output efficient detection and recognition of traffic lights for autonomous vehicles using cnn (pp. 49 56) sukkur iba journal of emerging technologies sjet | vol. 5 no. 2 july – december 2022 52 2.1. yolo v3 in our approach, we have used yolo, often called a clever cnn, because it is superfast and supposed to be run in real-time [2122]. it incorporates features learned by a deep convolutional neural network for detecting the objects it was first defined by joseph redmon and ali farhadi in the seminal 2015 paper. this model depends on the “darknet” architecture shown in fig.3 [24]. it processes all image features; 2 fully connected layers are used for bounding box prediction for objects. mathematically, in terms of regression, an input image is divided into an s × s grid. furthermore, the boundary boxes comprise five elements including the object’s x and y coordinates that need to be detected in the input image. the other two elements are w and h. that is the width and height of the same image. the last and fifth element is the most important that reveals the confidence score. the confidence score predicts the presence of the object in the box, along with the accuracy of the boundary box that is indicated in fig. 4 fig. 4. elements of boundary boxes [24 this algorithm also has an appealing feature that enables the end-user to change the model size to make the trade-off between detection accuracy and speed [27]. consequently, we have made changes within the config file and a number of filters are being changed as per the classes selected for traffic light detection. fig. 5. steps of yolo algorithm for tld 2.2. hough transform to improve the results, a pattern recognition technique called hough transform (ht) is deployed. usually, it is used to extract lines, circles, and similar ellipses or conic sections. all around the world traffic lights are usually circular, in this case, yolov3 gives fp (false positives) due to biasness between the traffic light and traffic signs. in addition to this, yolov3 also struggles while detecting small objects in larger images. moreover, its need more enhanced detection and recognition capabilities in night light as well. in this regard, cht (circular hough transform) is efficient detection and recognition of traffic lights for autonomous vehicles using cnn (pp. 49 56) sukkur iba journal of emerging technologies sjet | vol. 5 no. 2 july – december 2022 53 used for feature extraction [24] that first converts an image from cartesian to polar coordinates. mathematically, a circle is represented as follows: (𝑥 − 𝑥𝑐𝑒𝑛𝑡𝑒𝑟 ) 2 + (𝑦 − 𝑦𝑐𝑒𝑛𝑡𝑒𝑟 ) 2 = 𝑟2 (1) the center of the circle is (x_center ,y_center ) and the radius is r, similarly for using circle hough transform (cht) for tld we have used a 2d accumulator with known r as shown in fig. 6. fig. 6. circle detection using ht [28] in other words, the number of unknown parameters is equal to the dimension of the accumulator of a given hough transform. ht requires pre-processing to find edges in the original traffic light image, at first traffic light images are converted into binary operation with threshold operation that is followed by a morphological operation to remove background noise, these are depicted in fig. 8. as compared to cnn-based models image processing approach is quite uncomplicated, however, it undergoes critical phases such as thresholding, and filtering [26]. in this case, opencv is preferred because it enables to hough gradient method for gradient information of traffic light edges. 3. experimental results the proposed model has been trained and tested on a total of 500 images at a resolution of 608 x 608 pixels of the bosch small traffic lights dataset, 85 % of images are used for training; while 15 % are used for the test. the annotations include bounding boxes of traffic lights as well as the color of each traffic light. it is known as an accurate dataset for visionbased traffic light detection [21]. the bosch dataset is selected because it allows easy testing of objection detection approaches, especially for small objects in larger images in different lighting environments. 𝐴𝑐𝑐𝑢𝑟𝑎𝑐𝑦 = 𝑇𝑃+𝑇𝑁 𝑇𝑃+𝑇𝑁+𝐹𝑃+𝐹𝑃 (2) at first, traffic light detection has performed using yolo v3. the bosch lite dataset is trained on images with 3 classes (red, yellow, and green) while available unseen test images are used for testing purposes. the following figures show detected traffic lights on the trained model, all three lights including red, yellow, and green are indicated within bounding boxes along with confidence scores. efficient detection and recognition of traffic lights for autonomous vehicles using cnn (pp. 49 56) sukkur iba journal of emerging technologies sjet | vol. 5 no. 2 july – december 2022 54 (a) (b) (c) (d) fig. 7. output images yolo v3 in different lightening conditions. (a) green light detection (b) yellow light detection (c) red light detection (d) misc. lights detection table i. summary of results model frames tp fp day time efficiency night time efficiency yolov3 day: 1509 1504 5 99.68 % 71.84 % night: 1450 1042 408 total: 2959 table ii. summary of cht results model frames tp fp day time eff. night time eff. cht day: 1509 1308 202 86.62% 79.51% night: 1450 1153 297 total: 2959 efficient detection and recognition of traffic lights for autonomous vehicles using cnn (pp. 49 56) sukkur iba journal of emerging technologies sjet | vol. 5 no. 2 july – december 2022 55 fig. 8. output images of cht 4. conclusion intelligent transportation systems can provide convenient, sustainable, safe, and secure transportability. however, autonomous vehicles undergo several challenges including infallible detection and recognition of traffic lights. these problems can be eliminated by using enhanced computer vision techniques. over the decades, the expeditious evolution of deep learning models introduced an object detection model yolo that can efficiently detect traffic lights in real time. contrary to this, real-life problems limit the accuracy and inference time. in essence, the development of a hybrid approach is needed to encounter the biasness between traffic lights and signs along with improved efficiency at night time. this study supports the development of a hybrid technique combining deep learning and handcrafted technique to improve traffic light detection and recognition in the best possible way. the experimental results successfully improve the night-time detection accuracy of traffic lights from 71.84% to 79.51%. references [1] rauf, muhammad, et al. "response surface methodology in-cooperating embedded system for bus’s route optimization." research journal of applied sciences, engineering and technology 5.22 (2013): 5170-5181 [2] sharma, s. and s.k. awasthi, introduction to intelligent transportation system: overview, classification based on physical architecture, and challenges. international journal of sensor networks, 2022. 38(4): p. 215-240. [3] yuan, t., et al., machine learning for next‐ generation intelligent transportation systems: a survey. transactions on emerging telecommunications technologies, 2022. 33(4): p. e4427. [4] ouyang, z., et al., deep cnn-based real-time traffic light detector for self-driving vehicles. ieee transactions on mobile computing, 2019. 19(2): p. 300-313. [5] li, x., et al., traffic light recognition for complex scene with fusion detections. ieee transactions on intelligent transportation systems, 2017. 19(1): p. 199-208. [6] jensen, m.b., et al., vision for looking at traffic lights: issues, survey, and perspectives. ieee transactions on intelligent transportation systems, 2016. 17(7): p. 18001815. [7] krizhevsky, a., i. sutskever, and g.e. hinton, imagenet classification with deep convolutional neural networks. communications of the acm, 2017. 60(6): p. 84-90. [8] redmon, j. and a. farhadi, yolov3: an incremental improvement. arxiv preprint arxiv:1804.02767, 2018. [9] mujahid, a., et al., real-time hand gesture recognition based on deep learning yolov3 model. applied sciences, 2021. 11(9): p. 4164. [10] chandana, r. and a. ramachandra, real time object detection system with yolo and cnn models: a review. 2022. [11] rehman, y., et al., small traffic sign detection in big images: searching needle in a hay. ieee access, 2022. 10: p. 1866718680. [12] sani, u.s., o.a. malik, and d.t.c. lai, improving path loss prediction using environmental feature extraction from satellite images: hand-crafted vs. convolutional neural network. applied sciences, 2022. 12(15): p. 7685. efficient detection and recognition of traffic lights for autonomous vehicles using cnn (pp. 49 56) sukkur iba journal of emerging technologies sjet | vol. 5 no. 2 july – december 2022 56 [13] kumar, s., et al. lane and vehicle detection using hough transform and yolov3. in 2022 2nd international conference on intelligent technologies (conit). 2022. ieee. [14] sahar, t., rauf, m., murtaza, a., khan, l. a., ayub, h., jameel, s. m., & ahad, i. u. (2022). anomaly detection in laser powder bed fusion using machine learning: a review. results in engineering, 100803. [15] bao, c., et al. safe driving at traffic lights: an image recognition based approach. in 2019 20th ieee international conference on mobile data management (mdm). 2019. ieee. [16] jain, n.k., r. saini, and p. mittal, a review on traffic monitoring system techniques. soft computing: theories and applications, 2019: p. 569-577. [17] vitas, d., m. tomic, and m. burul, traffic light detection in autonomous driving systems. ieee consumer electronics magazine, 2020. 9(4): p. 90-96. [18] gupta, a. and a. choudhary. a framework for traffic light detection and recognition using deep learning and grassmann manifolds. in 2019 ieee intelligent vehicles symposium (iv). 2019. ieee. [19] bach, m., d. stumper, and k. dietmayer. deep convolutional traffic light recognition for automated driving. in 2018 21st international conference on intelligent transportation systems (itsc). 2018. ieee. [20] iftikhar, m., et al., traffic light detection: a cost effective approach. 2022. [21] behrendt, k., l. novak, and r. botros. a deep learning approach to traffic lights: detection, tracking, and classification. in 2017 ieee international conference on robotics and automation (icra). 2017. ieee. [22] yadav, p.v., et al., aquavision: real-time identification of microbes in freshwater using yolov3, in soft computing for security applications. 2022, springer. p. 437448. [23] redmon, j., et al. you only look once: unified, real-time object detection. in proceedings of the ieee conference on computer vision and pattern recognition. 2016. [24] li, x., et al., a modified yolov3 detection method for vision-based water surface garbage capture robot. international journal of advanced robotic systems, 2020. 17(3): p. 1729881420932715. [25] chun, l. z., dian, l., zhi, j. y., jing, w., & zhang, c. yolov3: face detection in complex environments. international journal of computational intelligence systems, (2020). 13(1), 1153-1160. [26] gothankar, n., c. kambhamettu, and p. moser. circular hough transform assisted cnn based vehicle axle detection and classification. in 2019 4th international conference on intelligent transportation engineering (icite). 2019. ieee. [27] kulkarni, r., s. dhavalikar, and s. bangar. traffic light detection and recognition for self driving cars using deep learning. in 2018 fourth international conference on computing communication control and automation (iccubea). 2018. ieee. [28] ribeiro, b.m., et al. arbitrary ball detection using the circular hough transform. in proc. of the 15th portuguese conf. on pattern recognition, recpad. 2009. vol. 2, no. 2 | july december 2019 sjet | p-issn: 2616-7069 | e-issn: 2617-3115 | vol. 2 | no. 2 | © 2019 sukkur iba 13 bio methane from biogas, renewable energy resource for pakistan asif ali1 abstract: the major barriers in development of pakistan’s economy are dependency on inefficient and unaffordable energy technologies, thus it is an energy-short country. the future energy demands of the country can be fulfilled by opting renewable energy technologies. the number of biogas energy generation systems is increasing steadily, as they are generated with low-cost. pakistan’s 70% population is residing in rural areas, so biogas energy can be a good substitute. a national policy regarding the development of biogas energy technology is needed to enhance the biogas potential. this study focuses on control of agriculture waste by chemical absorption process, in which the biomass is converted into fuel. in this way not only, biomass is treated but renewable energy can be generated. the raw material, biomass, was fed to an anaerobic digester that operates at 35° and produces biogas along with sludge biomass. the mixture of biogas and sludge biomass was separated with the help of flash unit and further separation was done by centrifuge to get concentrated biomass and water. the raw biogas was compress from 1 bar to 5 bars in order to remove ammonia from biogas. the biogas was upgraded to bio methane in an absorption column by treating biogas with potassium hydroxide. the biomass potential of pakistan which is 853,500 tons/day can be utilized by using this process to generate 469,425 tons/day of bio methane. cost analysis indicated that the chemical absorption is feasible. keywords: biogas, hydrogen sulfide, chemical absorption, potassium hydroxide, bio methane, renewable energy. 1. introduction 1.1. energy situation in pakistan pakistan is facing energy crises, major energy resources are oil and gas, the country’s reserves of oil and gas are finite and hence oil is imported on a very large scale. the oil imported, covered approximately 31% of the country’s energy necessity. the oil import bill of pakistan increasing year by year, from it was 1 department of renewable energy engineering, uspcas-e, peshawar *corresponding author: chemasif85@gmail.com about $7 billion and increase to $12 billion in 2011. the conventional energy sources provide more than 99% of the energy and only 1% energy supply is from renewable sources. for the year 2010-2011, aggregate energy consumption was 38.8 million tons of oil, of which 38.5% was used up by the industrial sector, 3 0 . 9 % wa s c o n s u m e d b y transport, and agriculture only used 2% of the total intake. [1] asif ali, bio methane from biogas, renewable energy resource for pakistan (pp. 13 20) sukkur iba journal of emerging technologies sjet | volume 2 no. 2 july – december 2019 © sukkur iba university 14 1.2. renewable energy renewable energy is described as the form of energy which resources are naturally and can be replaced on a human timescale. the conventional (non-renewable) sources of energy are depleting at a faster rate day by day and this drawback is leading to move towards the renewable energy. renewable energy has a vast potential to cover our future energy demands and overcome worldwide energy crisis. the natural resources of renewable energy include; wind, biogas, tides, rain, geothermal heat and sunlight, etc. availability of renewable energy resources over wide geographical regions differentiate it from other conventional energy sources, which are limited to a few countries. another main advantage of using renewable resources is that, air pollution caused by burning of fossil fuels, can be controlled and develops public health by reducing sickness ratio caused by pollution and save linked health costs. [2] fig 1: pakistan energy supply by source fig 2: pakistan energy consumption by sector 1.3. biogas a blend of various gases collected by the disintigration of organic matter in the absence of oxygen is known as biogas. agriculture waste, municipal waste, plant material, sewage, food waste, and animal waste etc. are the raw materials from which biogas can be extracted. the biogas composition is mostly composed of methane (ch4) and carbon dioxide (co2) and addition to this, insignificant quantity of hydrogen sulfide (h2s), moisture and siloxanes may have also present in the biogas. the methane, and other gases, hydrogen, and carbon monoxide can be combusted or oxidized with oxygen. this energy release upon combustion let biogas to be used as: • fuel • heating purposes • gas engines [3] the waste can be treated by several processes: • open air windrow composting • incineration • landfill • mechanical biological treatment • in-vessel composting • anaerobic digestion. [4] table i: composition of biogas 1.4. history of biogas in pakistan the history of biogas in pakistan is almost fifty-nine years old. in 1969, the first farmyard manure plant was buildup in sindh to produce biogas from animal and farm waste. the government of pakistan inaugurated total gases percentage % methane 50 – 75 carbon dioxide 25 – 40 nitrogen 0 – 10 hydrogen 0 – 1 hydrogen sulfide 0 – 3 oxygen 0– 2 asif ali, bio methane from biogas, renewable energy resource for pakistan (pp. 13 20) sukkur iba journal of emerging technologies sjet | volume 2 no. 2 july – december 2019 © sukkur iba university 15 4,140 biogas plants under a comprehensive biogas scheme in 1974 up-to 1987. in 1982 to 1985, one thousand biogas plants were installed in several districts of punjab. another seven hundred and fifty family size biogas plants were installed all over punjab as a scheme a program ‘adaptation of biogas technology to mitigate the energy crises’ of agriculture department in 2009-2010. [5] 1.5. biogas potential in pakistan biogas may be beneficial to overcome the present energy disaster in pakistan and its cost is 35 to 50 percent less than that of other energy resources like, charcoal, kerosene oil and firewood. nowadays a big problem in pakistan is energy crises and it could be handled by enriching livestock and dairy development. animal dung can be utilized for the production of gas and a high-quality fertilizer as a byproduct. pakistan has approximately 29.9 million buffalos, 33 million cattle. one buffalo or cow produces 15 kg dung per day and there are 56,900,000 animals and if 50 percent of this dung is collected, then 426,750,000 kg of dung every day is available for the conversion to biogas. a biogas plant can install within rupees 40,000 to rupees 150,000 and its components are easily attainable in the local market. [6] 1.6. bio methane the upgraded form of biogas by removing traces like, hydrogen sulfide, carbon dioxide and moisture is known as bio methane. biogas is the product of anaerobic digestion of raw materials like dead plant material, manure, sewage, organic waste, etc. although its usability is recognized for fairly some time, bio methane might be used as a possible source of energy, specifically for fossil fuels. installation of plants for the producing of bio methane is new and initiated only in the recent years as an end result of the mounting prices of natural gas and high electricity prices. bio methane and fossil fuel derived methane has a great difference between each other even though the certainty that both are originated from organic matter, and are same chemically. the source of fossil fuel derived methane is old fossil residue of organic matter that lies buried deep in the ground from thousands or millions of years. while for the bio methane resources are “fresh” organic matter, available everywhere worldwide which marks it a renewable source of energy. [7] 1.7. different technologies for upgrading biogas to bio methane 1.7.1 water and polyethylene glycol scrubbing as carbon dioxide and hydrogen sulfide are more soluble in water than methane, water scrubbing is used to draw out these traces from biogas. in this method, traces are absorbed in a counter-current operation. first, the biogas is pressurized and then fed to a packed column from the bottom while at top, water is fed. the water contaminated very quickly when high levels of hydrogen sulfide are to be treated which cause operational problem, thus stripping with it is not recommended. [8] 1.7.2 pressure swing adsorption in this method, few gas species are separated from a mixture of gases under pressure cohering to the specie’s molecular characteristics and affinity for an adsorbent material. special adsorptive materials (e.g. zeolites and active carbon) are utilized as a molecular sieve, which adsorb the intent gas species at high pressure. an additional step is needed before psa for the elimination of hydrogen sulfide, which is the main disadvantage of psa technology. [9] 1.7.3. cryogenic separation carbon dioxide, hydrogen sulfide and all other biogas traces can be sort out from ch4 as each contaminant has specific temperature and pressure at which it liquefies. this segregation process requires low temperatures, near -100 oc, and high pressures, almost 40 bars. asif ali, bio methane from biogas, renewable energy resource for pakistan (pp. 13 20) sukkur iba journal of emerging technologies sjet | volume 2 no. 2 july – december 2019 © sukkur iba university 16 the requirement of substantial process equipment, such as compressors, turbines and heat exchangers are the main disadvantage of this process. [10] 1.7.4. membrane separation in membrane separation the raw gas is passed through a thin membrane, some constituents are filtered out while the remaining components of the raw gas are accumulated at the surface of thin membrane. a ratio between high methane purity and high methane yield in the customized gas is created. relatively low methane yield and high membrane cost are the disadvantages of the membrane separation. [11] fig 3: chemical absorption method 2. methodology several researchers have worked on the different techniques used for the customization of biogas to bio methane. some of these methods are already discussed in the introduction section. according to literature review the feasible, economical, and environmentally friendly technique is chemical absorption. availability of several absorbents, like koh, naoh, and mea used in this process is another advantage of chemical absorption. according to grazia leonzio, among these absorbents koh is the suitable one, having low price and less environmental impact. [12] 2.1. chemical absorption reversible chemical bonds are developed between the solute and the solvent in chemical absorption. therefore, with a high energy input, regeneration of the solvent includes splitting of these bonds. chemical solvents are normally either aqueous solutions of amines (i.e. mono-, di-, or triethanol amine) or aqueous solution of alkaline salts (i.e. sodium, potassium and calcium hydroxides). almost complete removal of hydrogen sulfide is one of the major advantages of chemical absorption, also high efficiency and tendency to operate at low pressure are considerable advantages of chemical absorption. this process is generally used in industrial applications, and many other applications, such as natural gas purification. [13] 2.2. potassium hydroxide (koh) the absorbent used in this process is potassium hydroxide, generally called caustic potash which is an inorganic compound. due to its reactivity toward acids it has many industrial applications, most of which accomplishing its corrosive nature. koh is remarkable as the precursor to most soft and liquid soaps as well as several chemicals which contain potassium. [14] 2.3. overall process flow diagram the raw material, agriculture waste as biomass, and water was fed to an anaerobic digester that operates at 35 oc and produces biogas along with sludge biomass. the mixture of biogas and sludge biomass was separated with the help of flash unit and further separation was done by centrifuge to get concentrated biomass and water. the raw biogas from the flash unit was compress from 1 bar to 5 bars in order to remove ammonia from biogas. the biogas was upgraded to bio methane in an absorption column by treating biogas with potassium hydroxide. asif ali, bio methane from biogas, renewable energy resource for pakistan (pp. 13 20) sukkur iba journal of emerging technologies sjet | volume 2 no. 2 july – december 2019 © sukkur iba university 17 100 tons/day of biomass and 70% conversion of biomass is taken as basis. material and energy balances are applied on each unit by considering the following assumptions: • mostly theoretical based • steady state process • ∆w = ∆k.e = ∆p.e = 0 • 98% flash separation efficiency • 80% centrifuge efficiency for material balance the following equation is used: input + generation = output + accumulation + consumption for energy balance the following equation is used: q = ∑mi, out x ∆ĥi,out – ∑mi,in x ∆ĥi,in physical data such as different specific heat capacities used in the stoichiometric calculations is taken from ‘elementary principles of chemical processes by richard m. feldar’[15], while thermodynamic data such as different enthalpies, from ‘fundamentals of thermodynamics by michael j. moran & howard n. shapiro’[16] the main reaction occurring in the anaerobic digester is: ch1.7o0.35n0.1s + 0.975h2o -----→ 0.3375ch4 + 0.6625co2 + 0.1nh3 + h2s 2.4. individual equipment design length, diameter and volume for each equipment are calculated by using residual time and l/d ratio from literature, specific for each unit. for example, for the anaerobic digester: residual time = 10 days l/d = 1.7 [17] volume= residual time x volumetric flow rate 2.5. cost estimation cost is calculated for each unit by using the following formulas, and the cost is estimated for the whole process to calculate the payback period of the unit. • ce,1 = cb (q / qb) m fig 4: overall process flow diagram asif ali, bio methane from biogas, renewable energy resource for pakistan (pp. 13 20) sukkur iba journal of emerging technologies sjet | volume 2 no. 2 july – december 2019 © sukkur iba university 18 • ce,1 / ce,2 = index 1 / index 2 • total equipment cost (tec) = ce,2 fm fp ft cf= ∑𝑖 𝑓m fp ft (1 + fpip) ce + (fer + finst + felec + futil + fos + fbuild + fsp + fdec + fcont + fws) ∑𝑖 ce [18] 3. results 3.1. bio methane we have developed this process for an industrial scale and cannot use this process in laboratory because of the unavailability of such kind of equipment in laboratories. one of the best processes that we have selected is chemical absorption process in which biogas is upgraded to biomethane with the help of potassium hydroxide. by this process, we have collected 55 tons/day biomethane as output, from 100 tons/day biomass feed. this biomethane is purified from traces like h2s, co2 and nh3. the overall process as shown in figure 3.1 we have treated 55 tons/day of biomethane with 10 tons/day of koh as absorbent. the absorbent koh can be regenerated after treating with the biomethane in the form of produced salts. this regeneration of the absorbents makes this process economical and feasible. the overall process is simulated by using coco/cofe software. the input data and stream line compositions are adjusted in the flowsheet of cofe software, and then run the simulation. figure 3.2 shows the simulation of the overall process. fig 6: simulation of the overall process fig 5: overall process flow diagram with material balance asif ali, bio methane from biogas, renewable energy resource for pakistan (pp. 13 20) sukkur iba journal of emerging technologies sjet | volume 2 no. 2 july – december 2019 © sukkur iba university 19 3.2 individual equipment design parameters design parameters such as length, diameter and volume for each equipment are calculated as shown in the table. these parameters are calculated by using residual time and l/d ratio, taken from literature and mass flow rate from material balances around each equipment. the compressor used in this up-gradation process is single stage compressor [19], which compression ratio is 5. minimum rpm required for the compression is 672 and the power required for the compressor is calculated to be 0.94 kw table ii: equipment design parameters 3.3 payback period total purchased equipment cost is calculated by estimating the purchased cost of each equipment, as shown in the table. then total fixed cost for the whole plant was estimated. the values of several factors are taken from the literature. table iii: equipment purchased cost the total fixed cost for the whole plant estimated is $ 90600. other costs such as maintenance cost, labor cost, raw material cost, plant overhead, etc. as a factor of total fixed cost are estimated to be $ 11453. taking sale price as $ 0.45 / lge, [20], the payback period calculated for this plant is three years. 4. conclusions the biomass potential of pakistan which is 853,500 tons/day can be utilized by using this process to generate 469,425 tons/day of bio methane. the technique used in this process for the up gradation of biogas to bio methane is environment friendly, as the h2s gas is completely removed by treating the biogas with koh absorbent. the waste from this process is a high-quality fertilizer, which is a byproduct of this process. table iv: comparison between biogas and bio methane biogas bio methane methane 50-75 % >97 % carbon dioxide 25-50 % < 3 % oxygen 0-2 % < 0.5 % hydrogen sulfide < 0-6000 ppm < 5 ppm the cost of bio methane compared to other energy resources, charcoal, kerosene oil and firewood is 35 to 50 percent less. the deforestation rate can be control by using bio methane as a heating source. pollution like water, soil and air can be reduced by converting organic wastes to bio methane. all these benefits make this process feasible and sustainable. there are several reasons for not utilizing the biogas potential. some major reasons of them are that there is lack of awareness of the peoples about this technology, lack of training facility in this regard and follow up to address these problems. production of bio methane can be enhanced by establishment of biomethane directorate equipment length (m) diameter (m) volume (m3) anaerobic digester 13.209 7.77 627.3 flash chamber 0.24 0.08 0.185 centrifuge 3.84 0.48 3 absorption column 7.2 2.06 3.33 equipment cost ($) anaerobic digester 6437 flash chamber 3407 centrifuge 232 compressor 3277 absorption column 6353 asif ali, bio methane from biogas, renewable energy resource for pakistan (pp. 13 20) sukkur iba journal of emerging technologies sjet | volume 2 no. 2 july – december 2019 © sukkur iba university 20 which will carry out the r&d activities regarding the improvement of this technology. information regarding bio methane generation and advantages is to be disseminated through print and electronic media to develop awareness of the people about this technology. conduction of training sessions will be helpful to share the technical aspects of this technology. coordination with international experts will be more fruitful for the development of this technology. references [1] amjid et all, 2011, “biogas, renewable energy resource for pakistan. renewable and sustainable energy reviews”; 15 (6), pages 2833-2837. [2] ellabban et al, 2014, "renewable energy resources: current status, future prospects and their enabling technology. renewable and sustainable energy reviews”; 39, pages 748–764. [3] b.bharathiraja et al, 2016 “bio hydrogen and biogas –an overview on feedstock’s and enhancement process”; 810-828 [4] iyyanki v.muralikrishna “environmental management”;science and engineering for industry 2017, pages 431-462 [5] waqar uddin et al, 2016 “biogas potential for electric power generation in pakistan: a survey”; pages 25-33 [6] www.blog.paksc.org, “biogas can end energy crisis”; retrieved october 2, 2016 [7] www.biomethane.org.uk, “what is bio methane”; retrieved october 2, 2016. [8] wojciech m. budzianowski, 2011, “benefits of biogas upgrading to bio methane by high-pressure reactive solvent scrubbing, biofuels”, 6, pages 1220. [9] alonso-vicario et al, 2010, “purification and upgrading of biogas by pressure swing adsorption on synthetic and natural zeolites. micro porous and mesoporous materials.”; 134, pages 100-107. [10] e. ryckebosch, m. drouillon, h. vervaeren, 2011, “techniques for transformation of biogas to bio methane. biomass and bioenergy”; pages 16331645. [11] pradeep et al, 2016, “biogas upgrading technologies: a review. international journal of recent technology science & management”, pages 2-4. [12] grazia leonzio, 2016, “upgrading of biogas to biomethane with chemical absorption process: simulation andenvironmental impact. journal of cleaner production”; pages 364-375. [13] pradeep et al, 2016, “biogas upgrading technologies: a review. international journal of recent technology science & management”, pages 2-4. [14] h. schultz et al, 2005, “potassium compounds in ullman’s encyclopedia of industrial chemistry”. [15] richard m. feldar “elementary principles of chemical processes”; pages 635-637. [16] michael j. moran & howard n. shapiro “fundamentals of thermodynamics”; pages 763-765. [17] abeam khalid et al, 2011, “the anaerobic digestion of solid organic waste, waste management”; pages 17391744. [18] robin smith “chemical process design and integration”; pages 17-33. [19] www.gasequipment.com/catalogs/cryogen ic/pdf/blackmer/compressors/comp%20sele ction%20and%20sizing.pdf, “steps to compressor selection and sizing”; retrieved january 24, 2017. [20] www.irena.org/costs/transportation/bio methane https://www.sciencedirect.com/science/article/pii/s0016236116307682#! https://www.sciencedirect.com/science/article/pii/b9780128119891000178#! https://www.sciencedirect.com/science/book/9780128119891 https://www.sciencedirect.com/science/book/9780128119891 https://www.sciencedirect.com/science/article/pii/s1364032115010539#! http://www.blog.paksc.org/ http://www.biomethane.org.uk/ http://www.gasequipment.com/catalogs/cryogenic/pdf/blackmer http://www.gasequipment.com/catalogs/cryogenic/pdf/blackmer vol. 2, no. 2 | july december 2019 sjet | p-issn: 2616-7069 | e-issn: 2617-3115 | vol. 2 | no. 2 | © 2019 sukkur iba 47 enhancing energy efficiency in temperature controlled dynamic scheduling technique for multi processing system on chip hamayun khan1, muhammad yousaf ali khan1, qaiser bashir2, muhammad usman hashmi3, irfan ud din3 , shahid khan4 abstract: 1 department of electrical engineering, gomal university, d.i.khan, kpk, pakistan 2 department of electrical engineering, the university of lahore, lahore, pakistan 3 department of computer science, superior university, lahore, pakistan 4 united consulting services, d.i.khan, kpk, pakistan microprocessors designs consist of many micro level chips that reaches to a state where thermal upsurge occurs due to rapid processing of data and effect (reduce) their efficiency in many different aspects. that production of heat can cause disintegration which makes the chips disable of doing many functions they are assigned to perform. embedded devices are designed to combine hardware and software, software integration can insert to hardware to perform some specific function. multicore embedded devices are in different shapes and dimension. it has various applications on larger scale in networking and nuclear powerhouses to small multimedia players printers, automobiles, cameras mobile handset due to higher demand of power the energy becomes the major concern of the multicore devices for this a thermal aware scheduling algorithm has been proposed that consider the migration of load from higher state to that of lower state and considers all type of tasks and forecast them according to the priority by maintaining the previous history. the proposed technique also considers various thermal values by consulting the previous priorities of task on multicore systems. migration policy is used to share load from one core to another the algorithm efficiently decreases almost 3℃ temperatures at 40% utilization and the energy utilization is 221.3 j which is 3.12 % improved as compared to the global edf. keywords: storm, atmi, dynamic power management, dynamic thermal management 1. introduction now a day’s systems are getting advanced and they are characterized as they have “real time” necessities to operate efficiently. in such embedded machines, the performance of the system does not consider those results that come at the end of complete simulation of a task in a multi-core system, but consider the duration during which the required results can be achieved [1]. such kind of systems is generally recognized as “real time systems”. these systems are usually linked to such applications that need hamayun (et al) enhancing energy efficiency in temperature controlled dynamic scheduling technique for multiprocessing system on chip (pp. 47 54) sukkur iba journal of emerging technologies sjet | volume 2 no. 2 july – december 2019 © sukkur iba university 48 to have a smooth operation for all the applications that required reliability and cannot afford any erroneous results in such real time systems all the deadlines meet at the accurate time and no chances for the system to miss its deadline. if a deadline is missed a failure as response can occur. these devices are called hard real-time systems a very common examples on larger scale for hard real time systems are avionics systems, textile industries, nuclear power plants, and also those devices that operates with wire systems established by present advanced automobiles [2, 3]. 'figure 1 illustrates the block diagram of real time system'. while on other side systems in which the real time limit exists, but the system has the ability to function weather a multi-core system missed the deadlines or either releases late. such type of system is recognized as “soft real time embedded system”. these embedded devices are safer as compared to hard. if the time limit for each task is missed and yet the system is functional such systems are known as “soft” real time systems. the performance of the system can be slightly disturbed and can affect the total performance of the system. such systems can be used in networking of cellular systems [4]. while there is another system in which the missing of deadline is acceptable. in this case, the deadline of the task takes place. then there is no improvement in the overall results either such systems are known as “firm” real time such systems that can afford delay of few seconds like a server of network that can afford delay. a usual real time system can behave as hybrid. sometime it behaves as “hard” real time, for which all the deadlines can meet according to their arrangements for the efficient and safe functionality of the system and some other embedded aspects like “firm” and “soft” real time where the infrequent failure is acceptable. there are few characteristics of rtes are as follow [5]. in real-time embedded systems the overall accuracy of the system depends on both the useful accuracy of the system and also on time constraints. real-time systems know about significant information of the application running on the system. real time system depends on deadlines predictability and consistency. fault acceptance characteristics. hard, soft and firm are those real time systems that are commonly used everywhere and they are linked with a conventional multi-core system. these are further categorized in few other types like interactive real time that gives response to a user while the application is in running mode these types of embedded devices depend on time so the user can expect the response of the system well on time. in such cases the user can have a better system’s speed and have a continuous process and have very less chances of missing a deadline such systems have almost the same characteristics like soft real time embedded systems. all through in this research work, the word “real time embedded system” is concerned with properties of an embedded systems and the real time. those devices that are in real time embedded system category have a larger number of common characteristics. real time systems have characteristics like embedded while embedded systems usually have characteristics like real time on larger level or either on smaller extent [6]. fig 1: block diagram of real time system. a. events in real-time systems in real time systems events are categorize in two forms. hamayun (et al) enhancing energy efficiency in temperature controlled dynamic scheduling technique for multiprocessing system on chip (pp. 47 54) sukkur iba journal of emerging technologies sjet | volume 2 no. 2 july – december 2019 © sukkur iba university 49 synchronous events: the release time assigned to all the tasks of an application is same. asynchronous events: the release time assigned to all the tasks of an application is random. figure 2 describes how a real time system works with synchronous and asynchronous events. fig 2: a simple view of real-time systems [7] b. function of rtes there are few functions of real time embedded systems. rts, nuclear power plants monitoring and scheduling, emb, printer, mp3 player and cell phone. rtsemb cardiac pacemaker. fig 3: an input/output structure of real time systems rtes are those systems for which it is necessity to execute the set of jobs allotted to it firmly within the pre-set limit restrictions. which is guaranteeing that all time-critical tasks are handled within time is called real time system with hard deadlines. these tasks trust deeply on computational analysis and data plays an important role for achievement of the specific task to avoid scheduling issues all the resources that are distributed try to meet the time constraints for the task not to miss any deadlines [8]. 2. literature review real-time systems are divided into hard and soft. the scheduling mechanism for hard are functional for soft real-time scheduling. static and dynamic are the two further types of hard real time scheduling. the scheduling choices are usually occupied during the compilation time of task that depends on previous information about task set constraints [9]. static scheduling occurs when the completing time for all the tasks are in the condition where scheduling by the scheduler finds earlier to the start of execution. tasks in which the information has some deadlines and the time for their execution is required are called static scheduling. the scheduling techniques occur during offline execution of tasks are static. in difference to this, dynamic scheduling makes quick decisions when the task is in running state by finding the set of tasks currently executing. this type of scheduling affords flexibility. dynamic scheduling represents such scheduling where the execution time for the task is not continuous and changes with time according to scheduler instructions. during execution the process is completed dynamically when there is a limited priority assign to a task. in such order task are executing according to the plan settled during run time and deviates by the instructions provided from the scheduler. executions of tasks with or without any issue are likely with both static and dynamic scheduling. real time operating system proposed various scheduling mechanisms. all these methods for scheduling have that issue that they allow prompt tasks to achieve execution by disturbing the execution of running tasks. all of them fall in the hamayun (et al) enhancing energy efficiency in temperature controlled dynamic scheduling technique for multiprocessing system on chip (pp. 47 54) sukkur iba journal of emerging technologies sjet | volume 2 no. 2 july – december 2019 © sukkur iba university 50 classification of non-preemptive scheduling [10]. there are few scheduling characteristics that are necessary for scheduling of a multi core real time system that are as follow [11, 12, and 13]. • guaranteeing that system timing restraints are meeting. • avoid synchronized installment of devices and mutual resources. • attaining a state where utilization is very high. • confirms that the dispatch cost of a realtime systems must be low fundamentally, the scheduling problem includes expressing a plan for the implementation, execution and completion of all the tasks [14]. due to advancement in embedded technology periodic activities shows more computational demand on a larger scale in a multi-core system these activities are categories in three types in a task model that are periodic, a periodic and sporadic. figure 2-9 describes the various categories of jobs that are used in a processor' [15]. fig 4: categories of task model c. periodic task in system monitoring periodic scheduling plays very important role periodic tasks usually occurs during control loops. these kinds of activities are continuously executing on definite rates. periodic task repeats itself at specific periodic time interval in a continuous manner e.g. control loops, sensor reading [16]. 'figure 5 illustrates how periodic tasks are scheduled for the completion of their jobs in a specified time. for better scheduling of task few notations are introduced that are as follow. for generic task sets i represents a periodic task while ti represents the time period of a general periodic tasks and øi represents the phase of task i. tin represents the nth occurrence to a task “i” and ria represents the release discharge duration for nth instance of task i in periodic task there are few major parameters that are used are written below. reaction duration of an occurrence of task is the time in which the instance is finished. the time starts and calculates from the start of an instance to the discharge of a task at that time instance it is finished. rak = fak tak significant instant of a task: the time when larger response is created at the release of a job. relation when release of a task occurs: among two continuous instants the major deviation of change is known as relative release of a task. rrja = max| (2i, fc-ra,fc) (2i,fc-a-ra,fc-a). complete discharge jitter of a job the instantaneous change in the duration between a single point instance and the maximum instant in which the deviation of a task occurs [43]. arja =max (2a, fc – ra) min (sa, fc – ra). there are three basic categories of scheduling algorithms that uses periodic tasks are rate monotonic scheduling, earliest deadline first scheduling and deadline monotonic scheduling. fig 5: periodic task model hamayun (et al) enhancing energy efficiency in temperature controlled dynamic scheduling technique for multiprocessing system on chip (pp. 47 54) sukkur iba journal of emerging technologies sjet | volume 2 no. 2 july – december 2019 © sukkur iba university 51 d. a periodic task a periodic task can occur at any time interval when the task is in running mode. there is no specific instant for the occurrence of aperiodic task. aperiodic task can have very elastic deadline and sometime aperiodic task doesn’t have any deadlines e.g. alarm clocks and all emergency embedded devices that can arrive at any time instant during emergency like robotic cars and obstacle avoidance system [17]. figure 6 illustrates how aperiodic tasks are scheduled and jobs occur at any time instant. 3. problem statement the main objective and focus of this research work is chip (reliability) that is the most important issues in multi core embedded technologies. high temperature causes multiple performances and reliability issues. fig 6: a periodic task model [18] task migration is the way to avoid high temperature and improve performance. however accurate prediction about the coolest core and the task which needs to migrate to control the chip temperature is the major design issue in task migration techniques. our technique considers all types of tasks including hot and cold task to accurately predict the temperature of the core in running mode and also use preciously thermal history to precisely check the chip temperature for the selection of cold core. a task migration technique based on previous history by considering workload of running core to predict the future temperature and coolest cores. this technique improves the reliability by avoiding thermal issues [19]. 4. experimental technique the major components include a task producer where user can create random task sets in xml file that contains different parameter. this xml input file is used as an input for the simulation tool. the simulation tool for real-time multiprocessor scheduling can simulate the input file according to the scheduling policy and developed the power profiles according to the set of parameters given in xml file. these power profiles generated from storm can be saved in a text output file. the xml file contains all the information of task sets. a temperature model can also analyze the thermal responses of different scheduling algorithms. a statistical testing mechanism is used to test a many data set. these data sets are already stored produces thermal profile when used with some hardware constraint in thermal model atmi and a power model is used for each core comprises of static and dynamic power. total power = dynamic power + static power dynamic power = c × f × v therefore, c is the switching capacitance. f is the frequency and v is the supply voltage static power = leakage current × v flow chart we have proposed technique for octa core multiprocessing leat processor in which the scheduler will first check the number of task jobs as shown in figure 7. that is running in an application. primarily the value of counter is zero for all 8-cores in a multiprocessing leat processor. the scheduler is able to determine the constraint and values of every individual task. so, the counter for all the cores is initially zero. the configuration of core will be selected on the basis of least temperature and lower power of consumption among all other configurations once the core with least temperature is hamayun (et al) enhancing energy efficiency in temperature controlled dynamic scheduling technique for multiprocessing system on chip (pp. 47 54) sukkur iba journal of emerging technologies sjet | volume 2 no. 2 july – december 2019 © sukkur iba university 52 selected its counter in running mode is rapidly rising. in such case when the temperature of the core in running mode is less than the maximum allowable temperature then the scheduler will perform normal process of task execution. fig 7: flow chart 5. experimental results in this section we discuss our experimental results that illustrates the temperature variation between the curves of proposed edf and global edf. proposed edf considers reliability and performance parameter so only those cores are in running state that is in working condition. in the beginning exponentially, temperature on chip rises and then arrive at a steady state level. at 13% utilization factor the global edf has 5℃ more temperature on chip as fig 8: thermal cycling under 80mhz for cpu1 & cpu2 at low utilization factor fig 9: thermal cycling under 80mhz for cpu1 & cpu2 at high utilization factor hamayun (et al) enhancing energy efficiency in temperature controlled dynamic scheduling technique for multiprocessing system on chip (pp. 47 54) sukkur iba journal of emerging technologies sjet | volume 2 no. 2 july – december 2019 © sukkur iba university 53 fig 10: thermal cycling under 80mhz for cpu1, cpu2, cpu3 and cpu4 at low utilization factor fig 11: thermal cycling under 80mhz for cpu1, cpu2, cpu3 and cpu4 at high utilization factor 6. conclusion and future work in this research work functional simulation on storm and thermal model and proved its practicability in the context of mpsoc. a large amount of techniques now a days doesn’t consider the affect of environmental temperature which can be investigated in future work. majority of the current algorithms dsefines only for homogeneous multi-core systems which can be extensive to heterogeneous multi-core systems. references [1] matt bach. how ambient temperatures affect your pc. temperatures-affect-your-pc-158/, written on august 15, 2012. [2] shekhar borkar. design challenges of technology scaling. ieee micro, 19(4):23– 29, july 1999. [3] thidapat chantem, xiaobo sharon hu, and robert p. dick.temperature-aware scheduling and assignment for hard real-time applications on mpsocs. ieee trans. vlsi syst., 19(10):1884–1897, 2011. [4] jian-jia chen, shengquan wang, and lothar thiele. proactive speed scheduling for realtime tasks under thermal constraints. in proceedings of the 2009 15th ieee symposium on real-time and embedded technology and applications, rtas ’09, pages 141–150, washington,dc, usa, 2009. ieee computer society. [5] h. khan, m. u. hashmi, z. khan, r. ahmad, and a. saleem, “performance evaluation for secure des-algorithm based authentication & counter measures for internet mobile host protocol,” ijcsns int. j. comput. sci. netw. secur. vol.18 no.12, december 2018, vol. 18, no. 12, pp. 181–185, 2018. [6] farzan fallah and massoud pedram. standby and active leakage current control and minimization in cmos vlsi circuits. ieice transactions, 88c(4):509–519, 2005. [7] stephen h. gunther, frank binns, douglas m. carmean, and jonathan c. hall. managing the impacincreasing microprocessor power consumption. (q1):9, february 2001. [8] h. khan, m. u. hashmi, z. khan, and r. ahmad, “offline earliest deadline first scheduling based technique for optimization of energy using storm in homogeneous multicore systems,” ijcsns int. j. comput. sci. netw. secur. vol.18 no.12, december 2018, vol. 18, no. 12, pp. 125–130, 2018. [9] khan, h., bashir, q., & hashmi, m. u. (2018). scheduling based energy optimization technique in multiprocessor embedded systems. 2018 international conference on engineering and emerging technologies (iceet).doi:10.1109/iceet1.2018.8338643 [10] joohno kong, sung woo chung, kevin skadron, “recent thermal management techniques for microprocessors" acm computing surveys, vol. 44, no. 3, article 13, pp. 13:1-13:42, june 2012 hamayun (et al) enhancing energy efficiency in temperature controlled dynamic scheduling technique for multiprocessing system on chip (pp. 47 54) sukkur iba journal of emerging technologies sjet | volume 2 no. 2 july – december 2019 © sukkur iba university 54 [11] mehdi kamal, a. iranfar, a. afzalikusha, m.pedram,"a thermal stress-aware algorithm for power and temperature management of mpsocs" in edaa, 2015. [12] q. bashir, h. khan, m. u. hashmi, and s. ali zamin, “a survey on scheduling based optimization techniques in multi-processor systems,” in proceedings of the 3rd international conference on engineering & emerging technologies (iceet), superior university, lahore, pk, 7-8 april, 2016., 2016. [13] t. s. rosing, k. mihic, g. de micheli, "power and reliability management of socs,"in ieee transaction very large scale integrated system (vlsi), vol. 15. no.4, pp.391-403, 2007. [14]pratyush kumar,lothar thiele,"thermally optimal stop-go scheduling of task graphs with real time constraints,"in asp-dac, ieee press, pp. 123-128, 2011. [15] alexandru andrei, petru eles, zebo peng, marcus t. schmitz, bashir m. al hashimi, "energy optimization of multiprocessor systems on chip by voltage selection," ieee transaction on vlsi, vol 50, no.3, 2007. [16] "1965 – "moore's law" predicts the future of integrated circuits". computer history museum, 2007 [17] c. j. lasance, "thermally driven reliability issues in microelectronic systems: statusquo and challenges". microelectronics reliability, pp. 1969–1974, december 2003. [18] h. khan, q. bashir, and m. u. hashmi, “scheduling based energy optimization technique in multiprocessor embedded systems,” in 2018 international conference on engineering and emerging technologies (iceet). doi:10.1109/iceet1.2018.8338643, 2018. [19] h. khan, s. ahmad, n. saleem, m. u. hashmi, and q. bashir, “scheduling based dynamic power management technique for offline optimization of energy in multi core processors,” int. j. sci. eng. res. vol. 9, issue 12, december-2018, vol. 9, no. 12, pp. 6–10, 2018. [20] g. petrone, g. seagnuolo, r. teodorescu, '"reliability issues in photovoltaic power processing systems", ieee transactions, july, 2008. http://www.computerhistory.org/semiconductor/timeline/1965-moore.html http://www.computerhistory.org/semiconductor/timeline/1965-moore.html https://en.wikipedia.org/wiki/computer_history_museum https://en.wikipedia.org/wiki/computer_history_museum vol. 5, no. 2 | july – december 2022 57 evaluation of machine learning based network attack detection muhammad awais rajput1, muhammad umar2, adnan ahmed2, ali raza bhangwar3, khadija suhail memon2, misbah2 abstract: the growth in the internet and communication technologies has driven tremendous developments in various application areas such as smart cities, cloud computing, internet-ofthings, e-banking, e-commerce, and e-government. however, the advancements in networking infrastructure, hacking tools, and methodologies have enabled hackers to attempt newer and more complicated cyber-attacks. consequently, cyber-security has now emerged as a vital research area to address security concerns. traditional security mechanisms such as firewalls and anti-viruses are not enough to accurately detect intrusions. therefore, an intrusion detection system (ids) provides an additional layer of security to prevent intrusions through continuous surveillance of the network traffic. machine learning (ml) and deep learning (dl) techniques have been exploited to overcome the inherent deficiencies of ids such as accurately detecting intrusions, countering zero-day cyber-attacks, and reducing false positive rates. existing research has demonstrated that ml and dl-based techniques can efficiently detect patterns (features) from the network traffic and predict the behavior (normal or abnormal activity) based on these patterns. this research work first presents the concepts of ids, followed by a comprehensive review of the recent ml and dl-based schemes. later, a performance analysis of various ml algorithms such as decision trees (dt), random forest (rf), gradient booster (gb), and deep neural networks (dnns) is presented on a publicly available dataset. the performance is reported in terms of accuracy, f1-score, cross-entropy loss, and training and testing times. keywords: machine learning; intrusion detection systems; cyber security; anomaly detection 1. introduction the recent advancement in emerging technologies such as healthcare, telecommunication, education, intelligent transportation systems, smart grids, ecommerce and e-government, manufacturing and infotainment provide ease and quality of services to the people [1], [2]. despite the significant advantages, these technologies are exposed to numerous cyber threats and 1dept. of artificial intelligence, quaid-e-awam university of engineering, science and technology, nawabsah, pakistan 2dept. of telecommunication, quaid-e-awam university of engineering, science and technology, nawabsah, pakistan. 3dept. of computer systems, quaid-e-awam university of engineering, science and technology, nawabsah, pakistan. corresponding author: adnan.ahmed03@quest.edu.pk unauthorized access [3]. to mitigate and eliminate the impacts of these attacks, cybersecurity provides various methods and technologies, such as antivirus, encryption/decryption, firewalls, access control and ids, to protect data and network infrastructures [4]–[6]. although these methods can prevent various attacks, however, in-depth traffic analysis cannot be performed using these security techniques. mailto:adnan.ahmed03@quest.edu.pk evaluation of machine learning based network attack detection (pp.57-66) sukkur iba journal of emerging technologies sjet | vol. 5 no. 2 july-december 2022 58 for continuous network traffic surveillance, ids have been developed to perform deeper traffic analysis. however, the ids still poses challenges in detecting zeroday attacks and minimizing false alarm rates [7]. to overcome the limitations of existing ids schemes and to provide accurate, costeffective and efficient ids, machine learning and deep learning techniques have been integrated to learn network traffic’s features and then predict and distinguish between the benign and normal traffic patterns. in this paper, we evaluate the performance of machine learning algorithms such as decision trees (dt), random forest (rf), gradient booster (gb) and deep neural networks (dnns) on various cyber security attacks: denial of service (dos), remote to local (r2l), user to root (u2r) and probe. the work was tested with the publicly available dataset kdd cup99 and performance was evaluated in terms of accuracy and training time. the contributions of this paper are highlighted in the following: 1) a machine learning-enabled attack detection flow is implemented. 2) the performance of various machine learning algorithms including deep neural networks is evaluated on a publicly available dataset. the rest of the paper is organized as follows: section 2 presents the relevant literature and discusses the ml and dl-based ids schemes. section 3 presents the methodology and overall flow of the work. section 4 presents the results and discussion. finally, section 5 concludes the paper. 2. literature review the intrusion detection scheme based on linear discriminant analysis (lda), classification and regression trees cart has been used in [8]. for testing purpose, random forest and kdd cup 99 dataset has been used in manner that it is divided on 80-20 rule. the performance of ids schemes (lda, rf and cart) is evaluated in terms of accuracy and cappa. according to result analysis, the rf scheme performs better in accuracy (99.65%) than lda (98.1%) and cart (98%). in paper [9], a performance comparison of machine learning-based algorithms, knn, decision tree and adabooost, is performed using ton-iot data set. the 99.8% accuracy was achieved for adaboost scheme which was better than knn and decision tress schemes. the intrusion detection tree (intrudtree) machine-learning-based security model was proposed in [10], which predicts the unseen test cases accurately and also reduces the computational complexity by optimizing feature dimensions. the efficacy of proposed intrudtree was examined with cybersecurity datasets and performance was measured in terms of roc, accuracy, recall and precision. the performance of intrudtree was compared with naive bayes (nb), logistic regression (lr), k-nearest neighbor (knn), and support vector machines (svm). the intrudtress achieved better results than their counterpart. the paper [11] presented the variant of the fnn known as self-normalizing neural networks (ssn) and compare its performance with the fnn. the evaluation was implemented on the bot-iot dataset. the ssn scheme is better than fnn based on multiple metrics such as accuracy, precision, and recall as well as multi-classification metrics such as cohen cappa’s score. the authors in [12] used radial based function (rbf) for support vector machine for classifying dos, probe, r2l and u2r types of attack. two datasets namely “mixed” and “10% kdd cup99” datasets have been used for evaluating performance of intrusion detection scheme. according to result analysis, validation accuracy was estimated to 89.85% and 99.9% for mixed and kdd respectively. evaluation of machine learning based network attack detection (pp.57-66) sukkur iba journal of emerging technologies sjet | vol. 5 no. 2 july-december 2022 59 table 1: comparative analysis meng et al. [13] developed an intelligent knowledge-based alarm filter based on knnclassifier with objective function to minimize the false alarm rate. the darpa 1999 dataset was used to train the filter. a network environment was setup using snort and wireshark where real-world web traffic was monitored. snort detects various types of attacks and generated alerts. the generated alters were forwarded to knn-based alarm filter for further analysis thereby filtering and minimizing the false alarm rate. the result analysis showed that accuracy of the design system was 85.2% and f-score was 0.82. moon et al. [14] proposed a dtb-ids (decision tree-based ids) for detection and preventing advance persistent threat (apt). the proposed system executes the malicious code on the virtual environment and then analyze the behavior to detect apt. the result analysis depicts the accuracy of proposed system was 84.7%. the author in [15] proposed an ids that classify the non-labeled data using ladder network and then classify the non-labeled data using deep belief network (dbn). moreover, the proposed scheme also integrates the semisupervise learning with neural network with aim to achieve high accuracy with small number of labeled samples using kdd cup99 dataset. the detection accuracy was 99.18%. papers dataset ml methods dl methods performance metrics attack detection [7] kdd cup 99 lda, rf, cart - accuracy and kappa normal, probe, u2r and r2l [8] ton iot knn, ada boost - precision, recall, f1 score, accuracy, and roc normal, scanning, ddos, dos, password attacks [9] intrudtree knn, svm, lr, nb - precision, recdoi, f1score, accuracy, and roc dos malware [10] bot iot -fnn, snn precision, recall and f1-score, kappa score and mc normal, ddos, dos, and reconnaissance [11] kdd cup 99 svm -accuracy denial of service (dos), probe, user to root (u2r), remote to user (r2l) [12] darpa 1999 knn -accuracy and f1-score snort based attack detection and minimizing false alarms [13] malshare decision tree -accuracy apt attacks [14] kdd cup 99 -dnn accuracy, training and testing time denial of service (dos), probe, user to root (u2r), remote to user (r2l) [15] kdd cup 99 lr - accuracy and cpu time(s) normal. dos, probe, u2l, r2l [16] nsl-kdd -rnn-ids accuracy and training time normal, dos, probe, u2r and r2l evaluation of machine learning based network attack detection (pp.57-66) sukkur iba journal of emerging technologies sjet | vol. 5 no. 2 july-december 2022 60 an ids based on deep belief network (dbn) using logistic regression was proposed in [16]. in order to improve the overall performance of ids system, the multi-class logistic regression was trained on 10 epochs with pre-trained data of the 10% kdd cup99 dataset. a low false rate of 2.47% was measured and detection rate of 97.9% was achieved for the proposed scheme. a recurrent neural network (rnn) based ids was proposed by ying et al. [17] using nsl-kdd data set. the performance of proposed model was evaluated in binary classification, influence of number of neurons, learning rates and multi-class classification. the result analysis showed that multi-class classification achieved the training accuracy 99.53% and test accuracy 81.29%. the binary classification model achieves the training accuracy 99.81% and test accuracy 83.28%. a categorical comparison of recent ml and dl based works is provided in table -1 in an attempt to provide further insight on ml/dl methods, various attack types and datasets that have been recently adopted in this domain. 3. methodology this section explains our ml-based intrusion detection flow. first, we provide an overview of the main steps involved in the methodology. later, the key steps are explained in the subsequent subsections. figure 1 visualizes the overall flow of the intrusion detection using ml. the flow starts with the dataset available as the input. initially, a preprocessing step performs tasks to prepare the dataset for the next steps. the preprocessing is an essential step which when overlooked, could affect the accuracy of the later steps of the flow. an in-depth understanding of the dataset is made via visualization and correlation mapping of the features. figure 2 shows the correlation map of the dataset with only those features for which the correlation is higher than 0.6. the cleaned dataset is forwarded to the training step where essentially the dataset is divided into train and test sets. the train data is provided to the selected ml model for learning the patterns. the test part of the dataset is kept for prediction purposes for the later step. in the testing step, the trained model from the last step is evaluated by applying unseen data (that was initially kept in the test part of the dataset). 3.1. preprocessing the capability of quickly learning patterns in the data is what makes ml models preferrable over the traditional approaches [18]. however, for many applications areas, the datasets are not in a standard form. moreover, the data obtained from repetitive readings requires excessive steps to bring it in a form suited for further processing in the ml pipeline. the tasks to be performed in preprocessing step vary depending on the application and the type of data that is being dealt with. nevertheless, there is a set of techniques that have been commonly employed in most of the ml applications. in case of intrusion detection, we apply a sequence of common preprocessing tasks along with some specific tasks that favor the ids. next important task involves understanding of the feature set. for this purpose, correlation map could provide useful insight to check which features could be eliminated due to redundancy. this is really important in many cases including ids since the dataset (kddcup99) contains 41 features out of which many could be dropped. other visualizations could also be used to undertake dataset formatting such as class balancing. in certain supervised ml methods such as svm, feature mapping is required to represent features of data in suitable space. finally, suitable and relevant features are kept only for the next step. evaluation of machine learning based network attack detection (pp.57-66) sukkur iba journal of emerging technologies sjet | vol. 5 no. 2 july-december 2022 61 figure 1: overall flow 3.2. training and testing the training step starts by first splitting train/test data. this is done to avoid over/under fitting of the model. the overfitting effect refers a scenario where the model learns the patterns of a dataset during the train and when tested on the same data, provides extremely accurate results since it has already seen the data. in underfitting, the model suffers to finds patterns in the training data and when tested on the new data, the model accuracy is very low. the overfitting effect can be minimized by breaking the dataset with appropriate proportions of the training data to let the model learn the relationship of the data and enough samples in the test data to evaluate the model. the underfitting effect can be tackled by using well suited ml model and careful selection of the features to capture essential input/output pattern of the data. we divide the processed dataset with a proportion of 70% and 30% for training and testing of the model. this is done by invoking train_test_split function from sklearn library. then for the available training data, we utilize the most common seven ml methods from different python’s ml libraries e.g., sklearn and keras, to train the models. the testing data is prepared by stripping the class label column. the accuracy score of the model is computed by applying the test data to the trained model. 4. results in this section, we provide details on our experimental setup and obtained results for various ml techniques on the intrusion detection. 4.1. setup of experiment as discussed in the previous section, we use a standard dataset i.e., kddcup99, to evaluate ml techniques for accurate prediction of anomalies in the network traffic data. the dataset manipulation is performed mainly via python library pandas and numpy. for visualization purposes, we use matplotlib. for ml models except for dnn, python’s sklearn library is utilized, whereas for dnn model we use keras. the model parameters for all the ml models used in our evaluation are shown in table-2. evaluation of machine learning based network attack detection (pp.57-66) sukkur iba journal of emerging technologies sjet | vol. 5 no. 2 july-december 2022 62 figure 2: correlation matrix for attributes of the dataset 4.2. results and discussion for each ml classification method from table-2, we evaluate the performance along two key parameters i.e., time and accuracy. for time, we report training and testing times separately. figure 3 and figure 4 show the training and testing times, respectively, for all ml methods on the dataset. as can be seen from figure 1, simpler ml models tend to have smaller training times whereas models that involves more complex learning structure could spend more time in learning the relationship of data. in this case, the dnn took the largest training time on the dataset followed by gb, svc and lr. nb took the smallest training time but as we will see that costs us performance penalty on the accuracy front. table-2: ml algorithm parameters s. # model parameter 1 naïve bayesian (nb) default 2 decisions tree (dt) criterion="entropy max_depth = 4 3 random forest (rf) n_estimators=30 4 support vector machine (svm) gamma = 'scale' 5 linear regression (lr) max_iter =1200000 6 gradient boosting (gb) random_state=0 7 deep neural network (dnn) epochs=100 batch_size=64 activation=relu optimizer=adam for testing, all algorithms perform equally well except svc which took significantly larger time on the prediction for the testing part of the dataset. we believe that this increase evaluation of machine learning based network attack detection (pp.57-66) sukkur iba journal of emerging technologies sjet | vol. 5 no. 2 july-december 2022 63 might be the result of an increase in the support vectors during the prediction step. figure 3: training times for all ml methods figure 4: testing times for all ml methods in figure 5 and 6, we report the accuracy scores for all algorithms. in case of accuracy results, we see a similar trend for training and testing accuracy. all algorithms except nb could achieve accuracy higher than 90%. the highest accuracy is achieved by the rf algorithm (1.0). dt, svc, lr, gb and dnn achieve 0.990, 0.999, 0.993, 0.997, and 0.998 accuracy respectively. for testing accuracy, a similar trend can be observed. overall rf algorithm turns out to be the most accurate classifier with a very low training and testing time. to further evaluate the performance of the ml models, we employ a commonly used loss function i.e., cross-entropy loss and report the values for all algorithms in table-3. it is important to mention that other most common metrics for loss such as means squared error or mean arithmetic error are not applicable in our case since the problem at hand is classification rather than regression and thus these metrics cannot capture the loss function efficiently. cross-entropy loss function can better represent the training and testing performance in multi-class classification problems [19]. results of cross-entropy represent a general trend of slight increase in loss for testing except in case of nb classifier where testing loss is a bit lower. table-3: cross-entropy values for all algorithms alg. cross-entropy training testing nb 2.777 2.776 dt 0.025 0.026 rf 0.000 0.002 svc 0.005 0.005 lr 0.017 0.017 gb 0.048 0.052 dnn 0.041 0.042 in addition to accuracy which might not be sufficient to indicate a model’s performance, we attempt get further insight into the performance of the ml algorithms by computing another important quality metric i.e., f1-score that combines precision and recall into a single composite quality indicator. for f1-scores, we observe that the rf archives the highest f1-score (see figure-7) followed by svc and lr. the nb classifier could only obtain 0.45 making it the lowest in terms of f1score. 5. conclusion this paper presents a work on classification of network traffic for intrusion detection using machine learning techniques. intrusion detection has become a challenging task due to data explosion in the recent years driving novel attacks and evaluation of machine learning based network attack detection (pp.57-66) sukkur iba journal of emerging technologies sjet | vol. 5 no. 2 july-december 2022 64 penetration techniques from the hackers. manual techniques based on signatures of malicious activity could miss certain attack types or even could not respond to unknown threats. ml techniques are capable of learning complex patterns in the data and can classify unseen data with high accuracy. the experimental results provided in this paper show that ml techniques could separate normal and bad connections with great accuracy (up to 99.9%) on a standard dataset with computationally light-weight inference models. figure 5: training accuracy for all ml methods figure 6: testing accuracy for all ml methods figure 7: f1-score for all algorithms references [1] z. zhang et al., “artificial intelligence in cyber security: research advances, challenges, and opportunities,” artif intell rev, vol. 55, no. 2, pp. 1029– 1053, 2022, doi: 10.1007/s10462021-09976-0. [2] z. tang et al., “data augmentation for graph convolutional network on semi-supervised classification,” lecture notes in computer science (including subseries lecture notes in artificial intelligence and lecture notes in bioinformatics), vol. 12859 lncs, pp. 33–48, 2021, doi: 10.1007/978-3-030-85899-5_3. [3] t. t. nguyen and v. j. reddi, “deep reinforcement learning for cyber security,” ieee trans neural netw evaluation of machine learning based network attack detection (pp.57-66) sukkur iba journal of emerging technologies sjet | vol. 5 no. 2 july-december 2022 65 learn syst, 2021, doi: 10.1109/tnnls.2021.3121870. [4] n. chaabouni, m. mosbah, a. zemmari, c. sauvignac, and p. faruki, “network intrusion detection for iot security based on learning techniques,” ieee communications surveys and tutorials, vol. 21, no. 3, pp. 2671–2701, jul. 2019, doi: 10.1109/comst.2019.2896380. [5] p. parkar and a. bilimoria, “a survey on cyber security ids using ml methods,” in proceedings 5th international conference on intelligent computing and control systems, iciccs 2021, may 2021, pp. 352–360. doi: 10.1109/iciccs51141.2021.943221 0. [6] f. tao, m. akhtar, and z. jiayuan, “the future of artificial intelligence in cybersecurity: a comprehensive survey,” eai endorsed transactions on creative technologies, vol. 8, no. 28, p. 170285, 2021, doi: 10.4108/eai.7-7-2021.170285. [7] z. ahmad, a. shahid khan, c. wai shiang, j. abdullah, and f. ahmad, “network intrusion detection system: a systematic study of machine learning and deep learning approaches,” transactions on emerging telecommunications technologies, vol. 32, no. 1, jan. 2021, doi: 10.1002/ett.4150. [8] t. saranya, s. sridevi, c. deisy, t. d. chung, and m. k. a. a. khan, “performance analysis of machine learning algorithms in intrusion detection system: a review,” in procedia computer science, 2020, vol. 171, pp. 1251–1260. doi: 10.1016/j.procs.2020.04.133. [9] i. ; hidayat, m. ali, ; zulfiqar, and a. arshad, “machine learning based intrusion detection system: an experimental comparison.” [online]. available: https://edshare.gcu.ac.uk/id/eprint/51 79 [10] i. h. sarker, y. b. abushark, f. alsolami, and a. i. khan, “intrudtree: a machine learning based cyber security intrusion detection model,” symmetry (basel), vol. 12, no. 5, may 2020, doi: 10.3390/sym12050754. [11] o. ibitoye, o. shafiq, and a. matrawy, “analyzing adversarial attacks against deep learning for intrusion detection in iot networks,” in ieee global communications conference (globecom), 2019, pp. 1–6. [12] m. v. kotpalliwar and r. wajgi, “classification of attacks using support vector machine (svm) on kddcup’99 ids database,” in proceedings 2015 5th international conference on communication systems and network technologies, csnt 2015, sep. 2015, pp. 987–990. doi: 10.1109/csnt.2015.185. [13] w. meng, w. li, and l. f. kwok, “design of intelligent knn-based alarm filter using knowledge-based alert verification in intrusion detection,” security and communication networks, vol. 8, no. 18, pp. 3883–3895, dec. 2015, doi: 10.1002/sec.1307. [14] d. moon, h. im, i. kim, and j. h. park, “dtb-ids: an intrusion detection system based on decision tree using behavior analysis for preventing apt attacks,” journal of supercomputing, vol. 73, no. 7, pp. 2881–2895, jul. 2017, doi: 10.1007/s11227-015-1604-8. [15] m. nadeem, o. marshall, s. singh, x. fang, and x. yuan, “semi-supervised deep neural network for network intrusion detection,” 2016. [online]. available: https://digitalcommons.kennesaw.edu /ccerphttps://digitalcommons.kennesa w.edu/ccerp/2016/practice/2 evaluation of machine learning based network attack detection (pp.57-66) sukkur iba journal of emerging technologies sjet | vol. 5 no. 2 july-december 2022 66 [16] k. alrawashdeh and c. purdy, “toward an online anomaly intrusion detection system based on deep learning,” in proceedings 2016 15th ieee international conference on machine learning and applications, icmla 2016, jan. 2017, pp. 195–200. doi: 10.1109/icmla.2016.167. [17] c. yin, y. zhu, j. fei, and x. he, “a deep learning approach for intrusion detection using recurrent neural networks,” ieee access, vol. 5, pp. 21954–21961, oct. 2017, doi: 10.1109/access.2017.2762418. [18] f. deeba et al., “a novel image dehazing framework for robust vision-based intelligent systems,” international journal of intelligent systems, dec. 2021, doi: 10.1002/int.22627. [19] z. zhang, m. s.-a. in neural information, and undefined 2018, “generalized cross entropy loss for training deep neural networks with noisy labels,” proceedings.neurips.cc, accessed: jan. 20, 2023. [online]. available: https://proceedings.neurips.cc/paper/ 2018/hash/f2925f97bc13ad2852a7a5 51802feea0-abstract.html ieee paper template in a4 (v1) vol. 3, no. 2 | july december 2020 sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 13 a global system for mobile communication based resource allocation technique to control autonomous robotic glove for spinal cord implant paralysed patients using flex sensors hamayun khan1,2, muhammad yousaf ali khan1, irfan uddin2, muhammad usman hashmi2, junaid iqbal3, muhammad shaheer1, muhammad zunnurain1, muhammad umar1 abstract: the autonomous robotic glove is designed for paralysed patients, so they would be able to control several electrical appliances around them as well as send an alert message to a particular person. developing countries are trying to abate the problems of these patients as they depend on others to control nearby appliances both in home and in hospital. in this research we proposed a solution by development & implementation of robotic glove. the research implementation consists of two parts. first part is transmitter and second part is receiver. transmitter part mainly consists of flex sensors, arduino uno and hc-11. flex sensors are used to convert finger movements into different voltage levels, while arduino is used to read this information from flex sensors and convey it to arduino mega on receiving end as programed by predefined gestures. hc-11 is a serial wireless communication transceiver module which is used to transmit information from arduino uno to arduino mega on receiving side. receiver side consist of hc11, arduino mega, global system for mobile communication (gsm) module, optocoupler and triac. arduino-mega is used to read the received information and perform action accordingly. on this side we have different electrical appliances which are controlled by hand gestures of patients as well as gsm module which is used to send different messages to associated person. opto-coupler is used to isolate low power receiving circuit from high power load circuit. triac is used for switching of ac supply. it is portable, requires low operating power on a single lithium-ion rechargeable battery and having less weight thus user friendly and affordable. keywords: flex sensors, hc-11 module, arduino, opto-coupler, gsm module 1. introduction: in pakistan usually, the paralysed patients are not aware from the modern technologies and they feel helpless in front of others. several developing countries are trying to overcome the problems of these patients by creating and developing some kind of tools or methods through which paralysed patient can 1 department of electrical engineering, gomal university, d.i.khan, kpk, pakistan 2 department of computer science, superior university lahore, pakistan 3 department of quaid-e-awam university larkana-campus, pakista communicate with others and could live a comfort life as other healthy persons[1]. difficulties around the paralysed patient is increasing day by day usually patient find it difficult to control electrical appliances both in home and hospital and required another person help to either switch on or off the electrical appliances. paralysed patient face hamayun khan (et al.) a global system for mobile communication based resource allocation technique to control autonomous robotic glove for spinal cord implant paralysed patients using flex sensors (pp. 13 23) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 14 many difficulties just for daily routine work for example eating food, going to washroom, turn on and off electrical loads etc. to reduce their dependency on others we design a system which would help those patients and allow them to control their daily activities on their own [2]. this research the design of an inimitable product which helps those individuals who are suffering from the disease of paralysis and cannot manage their everyday activities, they are generally known as stroke patients. mostly these patients are sent home where they live a dependent life. we have designed and implemented a research which could help the paralysed patients to manage their everyday chores to some extent without being reliant on others [3]. this research shows the plan, execution, and assessment of smart framework for stroke patient. the framework, a glove, uses segments of motion acknowledgment resolving the issues of cost, nosiness, and precision while giving a structure to augmentations to the framework. the framework is assessed as far as its energy utilization to evaluate the adequacy and feasibility of a device. so we named it argfscip (autonomous robotic glove for spinal cord implant patients). there is no doubt every paralysed patient wants to live the life as healthy person. how many times we interact with the paralysed person or a person who cannot stay on your own feet, basically this life just offers a little room for a paralysed patient who cannot move and control anything. one way to boost the mentality and recovery of these patients is to encourage them by positive attitude. motivation is the tool which doesn’t let the paralysed patient to lose hope. it is the best tool and medicine for a paralysed patient who is suffering from such boring life so we wanted to design a research that can comfort the life of stroke or paralysed patient [4, 5]. paralyse or stroke patient can enormously decrease the self-rule and personal satisfaction of a patient while introducing a noteworthy repeating cost at home and h care centers. improve the system with a non-intrusive wearable sensor framework; the patient can recover a level of self-governance at a small amount of the cost of home medical caretakers [6,7]. 2. literature review usually paralysed patient find it difficult to control electrical appliances both in home and in hospital and require another help of person to either switch on/off the relevant devices. development & implementation of robotic glove to overcome the difficulty of paralysed patient which help them to live an independent and comfortable life robotic glove is designed for the patients who lost the mobility in their hands as well as in proper body due to the spinal cord injury so these patients rely on the caregiver to perform his basic task. paralysed patient required at least one person for support. the proposed research make it easy, we uses gestures reading technique to control the home appliances like fan, bulb, emergency bell and alert doctor by sending massage in case of emergency. so this robotic glove reduces the difficulties of paralysed patients and gives hope, patients, confidence, motivation and independence. robotic glove is a wearable hand rehabilitation solution for the paralysed patients there are many techniques which are used in the past for this purpose, some of them are speaking gloves for speechless persons [1]. hand gestures detection and recognition building system for stroke patients using supervised neural networks a flex sensor or bend sensor is a sensor that measures the amount of deflection or bending. usually, the sensor is stuck to the surface, and resistance of sensor element is varied by bending the surface. [2]. recent developments of robotic exoskeletons for hand rehabilitation. [3]. plan and implementation of the advanced wireless tongue drive [4]. sign language interpreter using a robotic glove [5]. development of robotic glove system for therapy treatment. [6] imu sensor based electronic goniometric glove for clinical finger development [7]. robotic glove for sign language communications [8]. robotic glove with motion acknowledgment capacity for the hearing and discourse weakened [9]. hand gesture recognition for physically disabled people [10,11] hamayun khan (et al.) a global system for mobile communication based resource allocation technique to control autonomous robotic glove for spinal cord implant paralysed patients using flex sensors (pp. 13 23) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 15 a low-cost robotic glove for hand functions evaluation [12]. helping-hand: a data glove technology for rehabilitation of monoplegia patients [13]. low cost robotic glove for remote control by the physically challenged. towards a battery-free wireless robotic glove for rehabilitation applications based on rfid [14]. 3. methodology this proposed research method consists of 2 parts. 1st part is transmitter and 2nd part is receiver. transmitter part consists of robotic glove controller which consist of flex sensors, arduino uno and hc-11. flex sensor is used to read the finger movement while arduino is used to program the glove to predefined gesture and read the information from flex sensor. hc 11 is a serial wireless communication transceiver module. hc 11 module is used for transmit an information which is get by arduino uno from flex sensor. 4. flow chart the flow chart in fig 2 tells that how this autonomous robotic glove can perform function, when user twist its finger as an input then this user finger’s output in form of digital will go to arduino uno. arduino uno recognize the gesture if predefined gesture is not recognize then it will return to start otherwise it will transmit signal to arduino mega through hc-11 which act as transmitter and receiver. arduino mega will perform two functions either it will send the message or turn on/off the load. 5. experimental results we obtained the output of flex sensor by using the analogue to digital converter. after this we relate these analogues to digital value to voltages then we check the output voltage of flex sensor at an angle zero degree (flat) and ninety degree (bend). we calculate reading for five fingers separately because variation for each finger is different. an analog to digital converter (adc) is an exceptionally helpful element that changes analog values to digital form. by changing over from the simple world to the computerized world, we can start to utilize hardware to interface to the analog world around us. the adc on the arduino is a 10-bit adc meaning it can distinguish 1,024 (2^10) discrete simple levels. fig 1: flex sensor communication with gsm module hamayun khan (et al.) a global system for mobile communication based resource allocation technique to control autonomous robotic glove for spinal cord implant paralysed patients using flex sensors (pp. 13 23) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 16 fig 2: flow chart hamayun khan (et al.) a global system for mobile communication based resource allocation technique to control autonomous robotic glove for spinal cord implant paralysed patients using flex sensors (pp. 13 23) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 17 for little finger at angle 0 ˚: voltage = 3 1023 ∗ 893 = 2.61 v fig 3: little finger flat resistance scope view in figure 3 along x-axix time is represented and along y-axix voltage is represented. one block along x-axix represents 1v and along y-axix one block shows 50ms time period. fig 4: flat resistance parameters figure 4 represents the voltage output at 0degree angle and we took the average value of voltage which is 2.36v for little finger. at angle 90 ˚: voltage = 3 1023 ∗ 615 = 1.80v fig 5: little finger bent resistance scope view figure 5 along x-axix time is represented and along y-axix voltage is represented. one block along x-axix represents 1v and along y-axix one block shows 50ms time period. fig 6:bent resistance parameters figure 6 represents the voltage output at 85-degree angle and we took the average value of voltage which is 1.76v for little finger. hamayun khan (et al.) a global system for mobile communication based resource allocation technique to control autonomous robotic glove for spinal cord implant paralysed patients using flex sensors (pp. 13 23) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 18 for ring finger at angle 0 ˚: voltage = 3 1023 ∗ 898 = 2.63 v fig 7: ring finger flat resistance scope view figure 7 along x-axix time is represented and along y-axix voltage is represented. one block along x-axix represents 1v and along y-axix one block shows 50ms time period. fig 8: ring finger flat resistance scope view figure 8 represents the voltage output at 0 degree angle and we took the average value of voltage which is 2.56v for ring finger. at angle 90 ˚ voltage = 3 1023 ∗ 665 = 1.95 v fig 9: ring finger bent resistance scope view figure 9 along x-axix time is represented and along y-axix voltage is represented. one block along x-axix represents 1v and along y-axix one block shows 50ms time period. fig 10: ring finger bent resistance parameters figure 10 represents the voltage output at 90-degree angle and we took the average value of voltage which is 1.88v for little finger. hamayun khan (et al.) a global system for mobile communication based resource allocation technique to control autonomous robotic glove for spinal cord implant paralysed patients using flex sensors (pp. 13 23) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 19 for middle finger at angle 0 ˚: voltage = 3 1023 ∗ 945 = 2.77 v fig 11: middle finger flat resistance scope view figure 11 along x-axix time is represented and along y-axix voltage is represented. one block along x-axix represents 1v and along y-axix one block shows 50ms time period. fig 12: middle finger flat resistance parameters figure 12 represents the voltage output at 0-degree angle and we took the average value of voltage which is 2.66v for middle finger. at angle 90 ˚: voltage = 3 1023 ∗ 650 = 1.90 v fig 13: middle finger bent resistance scope view figure 13 along x-axix time is represented and along y-axix voltage is represented. one block along x-axix represents 1v and along y-axix one block shows 50ms time period. fig 14: middle finger bent resistance parameters figure 14 represents the voltage output at 90-degree angle and we took the average value of voltage which is 1.84v for middle finger. hamayun khan (et al.) a global system for mobile communication based resource allocation technique to control autonomous robotic glove for spinal cord implant paralysed patients using flex sensors (pp. 13 23) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 20 for index finger at angle 0 ˚: voltage = 3 1023 ∗ 850 = 2.49 v fig 15: index inger flat resistance scope view figure 15 along x-axix time is represented and along y-axix voltage is represented. one block along x-axix represents 1v and along y-axix one block shows 50ms time period. fig 16: index finger flat resistance parameters figure 16 represents the voltage output at 0 degree angle and we took the average value of voltage which is 2.20 for index finger. at angle 90 ˚: voltage = 3 1023 ∗ 490 = 1.43 v fig 17: index finger bent resistance scope view figure 17 along x-axix time is represented and along y-axix voltage is represented. one block along x-axix represents 1v and along y-axix one block shows 50ms time period. fig 18: index finger bent resistance parameters figure 18 represents the voltage output at 90 degree angle and we took the average value of voltage which is 1.40v for index finger. hamayun khan (et al.) a global system for mobile communication based resource allocation technique to control autonomous robotic glove for spinal cord implant paralysed patients using flex sensors (pp. 13 23) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 21 for thumb at angle 0 ˚: voltage = 3 1023 ∗ 666 = 1.95 v fig 19: thumb flat resistance scope view figure 19 along x-axix time is represented and along y-axix voltage is represented. one block along x-axix represents 1v and along y-axix one block shows 50ms time period. fig 20: thumb flat resistance parameters figure 20 represents the voltage output at 0 degree angle and we took the average value of voltage which is 1.60v for thumb. at angle 90 ˚: voltage = 3 1023 ∗ 490 = 1.43 v fig 21: thumb bent resistance scope view figure 21 along x-axix time is represented and along y-axix voltage is represented. one block along x-axix represents 1v and along y-axix one block shows 50ms time period. fig 22: thumb bent resistance parameter figure 22 represents the voltage output at 90 degree angle and we took the average value of voltage which is 1.56v for thumb. hamayun khan (et al.) a global system for mobile communication based resource allocation technique to control autonomous robotic glove for spinal cord implant paralysed patients using flex sensors (pp. 13 23) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 22 above fig 23 describes the variation of voltage by twisting the all fingers including thumb with different angles. along x-axis angle is mentioned while along y-axis voltage variation is mentioned. at angle 0 to 90 voltage level variation is mentioned with different colurs. 6. conclusion many people in this world are paralyzed and disable and some of them are deaf and dumb. they are facing difficulties to communicate with others because the gesture language is not easily understood by the people. by using different types of sign gestures it is very difficult to communicate with them. but the our research is robotic glove for paralyzed patients or disable who are bed rest and can’t move from one place to another and always need him/her for any kind of help so by using this system they will be able to control home appliance independently. the system is constructed to read hands of finger movement and translate this particular hands movement into the analog form. this method is very easy to contact with others, in which the user does not need any type of training and this is wireless technique in which the patient can communicate with others within hundred meters range. so in any case of danger e.g. earthquake or fires, if the patient is in hazard and need to get a help so he can just move his/her hands finger than the message will be send to a particular person. finally; this small system will effect in helping the humankind which is really a greatest act. the research is made from electronics devices which are placed on hand glove that is wearable, portable and can be easily used by the paralyzed patient and do some work without any kind of other helping. this system is more effective, efficient and low cast which serves the different types of disable person. this task shows the execution of a basic hand glove, to help the physically tested or confined to bed patients. the glove when worn can be utilized to work electrical devices, by the straight forward flexing of the fingers. the activity is determined by the fingers curved. it is very easy to construct. its range is limited because of using hc-11. the range can be expanded by utilizing zigbee or hc-12. references [1] zimmerman, t. g. (1985). u.s. patent no. 4,542,291. washington, dc: u.s. patent and trademark office. [2] maharjan, p., bhatta, t., salauddin, m., rasel, m. s., rahman, m. t., rana, s. m. s., & park, j. y. (2020). a human skininspired self-powered flex sensor with thermally embossed microstructured triboelectric layers for sign language interpretation. nano energy, 76, 105071.. [3] aira patrice r. ong, nilo t. bugtai “recent developments of robotic exoskeletons for hand rehabilitation” de la salle university, manila, 0 0.5 1 1.5 2 2.5 3 0 20 40 60 80 100 v o lt a g e ( v ) finger angle index middle ring baby thumb fig 23: variation of voltage at different angles of fingers hamayun khan (et al.) a global system for mobile communication based resource allocation technique to control autonomous robotic glove for spinal cord implant paralysed patients using flex sensors (pp. 13 23) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 23 philippines. vol 4 ,issn 2449-3309,issue march 7-9, 2016 [4] abbas u1*, shaikh mz2, panhwer a2, turk sk1 and kumar n1. .“design and implementation of the advanced wireless tongue drive” journal of bioengineering & biomedical science| issn: 2155-9538 jbbs an open access journal volume 6 |issue 2 |1000185 published apr 26, 2016 [5] nikhita praveen ,naveen karanth ,m s megha “sign language interpreter using a robotic glove” international conference on advance in electronics, computers and communication 2014 ieee [6] h. khan, m. u. hashmi, z. khan, r. ahmad, and a. saleem, “performance evaluation for secure des-algorithm based authentication & counter measures for internet mobile host protocol,” ijcsns int. j. comput. sci. netw. secur. vol.18 no.12, december 2018, vol. 18, no. 12, pp. 181–185, 2018. [7] james connolly, joan condell, brendan o’flynn, javier torres sanchez, and philip gardiner.“imu sensor-based electronic goniometric glove for clinical finger movement analysis” ieee sensors journal, vol. 18, no. 3, february 1, 2018 [8] abhinandan das, lavish yadav, mayank singhal, raman sachan, hemang goyal, keshav taparia raghav gulati, ankit singh, gaurav trived.“robotic glove for sign language communications” department of electronics and electrical engineering indian institute of technology guwahati guwahati, assam 781039, india| 16-18 dec 2016 ieee [9] tushar chouhan, ankit panse, anvesh kumar voona and s. m. sameer. “robotic glove with gesture recognition ability for the hearing and speech impaired” 2014 ieee global humanitarian technology conference south asia satellite (ghtc-sas) | september 26-27, 2014 | trivandrum [10] h. khan, m. u. hashmi, z. khan, and r. ahmad, “offline earliest deadline first scheduling based technique for optimization of energy using storm in homogeneous multicore systems,” ijcsns int. j. comput. sci. netw. secur. vol.18 no.12, december 2018, vol. 18, no. 12, pp. 125–130, 2018. [11] izzeldin ibrahim mohamed abdelaziz. “a low-cost robotic glove for hand functions evaluation” international journal of robotics and automation (ijra) vol. 3, no. 1, march 2014, issn: 2089-4856 [12] yeasin ar rahman, mohammed moshiul hoque, khalid ibn zinnah, imam mohammad bokhary. “helping-hand: a data glove technology for rehabilitation of monoplegia patients” the 9th international forum on strategic technology (ifost), october 21-23, 2014, cox’s bazar, bangladesh 978-14799-6062-0/14/2014 ieee [13] khan, m. y. a. (2020). a high state of modular transistor on a 105 kw hvps for x-rays tomography applications. sukkur iba journal of emerging technologies, 2(2), 1-6. [14] khan, h., hashmi, m. u., khan, z., & ahmad, r. (2018). offline earliest deadline first scheduling based technique for optimization of energy using storm in homogeneous multicore systems. ijcsns int. j. comput. sci. netw. secur, 18(12), 125-130. http://ieeexplore.ieee.org/search/searchresult.jsp?searchwithin=%22authors%22:.qt.nikhita%20praveen.qt.&newsearch=true http://ieeexplore.ieee.org/search/searchresult.jsp?searchwithin=%22authors%22:.qt.naveen%20karanth.qt.&newsearch=true http://ieeexplore.ieee.org/search/searchresult.jsp?searchwithin=%22authors%22:.qt.m%20s%20megha.qt.&newsearch=true http://ieeexplore.ieee.org/search/searchresult.jsp?searchwithin=%22authors%22:.qt.m%20s%20megha.qt.&newsearch=true vol. 5, no. 2 | july december 2022 sjet | p-issn: 2616-7069 | e-issn: 2617-3115 | vol. 5 no. 2 july – december 2022 33 simulation based analysis of single unit and parallel connected three phase ac generators in quest campus larkana abdul hameed soomro1*, syed abid ali shah1, assadullah khauhwar1, sanaullah talani1, aijaz ahmed solangi1,talha soomro1, faraz ali khushk1 abstract: recently power crises are increasing day by day in pakistan due to a shortage of energy resources. the financial position of pakistan is too weak and is not in a position to install new power projects for the production of electrical power to meet the demand as per requirement. every consumer is trying to install the power-producing devices to meet the demand in order to run their institutional laboratories, offices, commercial plants, and industrial machines. electricity for resident people of villages of pakistan is not sufficient to run their home appliances and mostly solar systems has installed to meet the requirement in day time but in night time energy storage system is required, so cost will be increased and less illumination is received at night time. the generator is also one of the power producer devices to meet the consumers' demand to supply the electrical power to the load in absence of failure of power supply from utility companies. a single large unit is very expensive to run the small loads and consumes large amounts of fuel, so the parallel connection of two small generators is very beneficial to meet the demand as per requirement, resulting in cost savings, and less fuel consumption. quest campus larkana has installed two 50kva generators in parallel to supply the required power to the load in absence of a power supply to run their offices, workshops and laboratories, this minimizes the cost, and increases the reliability of the system. the matlab simulation model is developed to analyze the performance of the single unit generator and parallel connected generators. keywords: ac generators, power supply 1. introduction recently power crises are increasing day by day in pakistan due to a shortage of energy resources and poor financial position to install new power projects for the production of electrical power to meet the demand as per requirement [1]. educational institutions, hospitals, laboratories, industries, residential, and commercial consumers are facing power crises and very difficult to manage the workstations in absence of electrical power [2]. as shown in figure 01 the power demand in pakistan. every consumer of electricity is 1department of electrical engineering, quaid-e-awam university of engineering science and technology nawabshah campus larkana, sindh pakistan corresponding author: abdul.hameed@quest.edu.pk trying to maintain his power system in boundary wall through addition of standby system to provide facilities to students and officers in educational institutes, patients and their staff in hospitals, and increase in revenue of production industries [3, 4]. every country wants to run their industrial sector properly for development but due to the power quality problems and shortage of power, the required output is badly affected [5]. mailto:abdul.hameed@quest.edu.pk simulation based analysis of single unit and parallel connected three phase ac generators in quest campus larkana (pp. 33 41) sukkur iba journal of emerging technologies sjet | vol. 5 no. 2 july – december 2022 34 power quality can be improved by installing the devices [6, 7] but the shortage of power is a serious problem for proper manufacturing in the industrial sector [1]. electricity for resident people of villages of pakistan is not sufficient to run their home appliances and mostly solar systems have been installed to meet the requirement during day time but at night time energy storage system is required, so the cost will be increased and less illumination is received at night time [4, 8]. the shortfall of electrical power is increasing day by day in pakistan, cities are facing 6 to 8 hours of daily load shedding, villages are more than 12 hours in a day, and some of the villages are without electricity [2]. hospitals, medical laboratories, institutions, industries, and large commercial offices have large loads and they have also required stand-by systems to run their loads at day and night time [9]. electrical generator is one of the standby systems to meet the consumers' demand [10] which convert mechanical energy into electrical energy and available in small and large ratings to meet the consumers' requirement day and night. quaid-e-awam university of engineering and technology campus larkano was established in 2010 which is a constituent campus of the quest nawabshah. there are four engineering departments and initially, one batch was admitted in 2010 and installed 50kva generator to meet the power demand in case of failure. after increasing the laboratories, staff offices, and induction of more student batches one more 50kva generator was added in parallel to meet the demand. in case of low power requirement, only single unit is running and the other is remained off, this will give saving in consumption of fuel [11], so two small rating generators are beneficial instead of a single unit of large capacity which consumes large amount of fuel, and large in size. matlab simulation software is used to develop the model of a parallel connected generator to analyze the performance under small and large loads. different power companies are intensively taking part in investments to enhance wind generation and overcome the shortage of electrical power in pakistan [12], [13]. the utilization of oil and coal since 2015 has increased so we cannot more rely on oil and coal due to costly, which will directly hit the economy of the country [14]. natural gas is available in pakistan but the oil and gas company of pakistan (ogdcl) has declared that the natural gas will be reduced from 2025 to 2030 so we cannot rely on natural gas for the installation of more power plants in pakistan in order to meet the power demand [15]. figure 1 shows the supply-demand gap in pakistan from 2002-2030. section 2 ac generator section 3 parallel connection of generators section 4 parallel connected generators in quest campus larkana section 5 simulation results and discussions section 6 conclusions fig. 1. supply demand gap in pakistan 2002-2030 2. ac generator the generator is a device that converts mechanical energy into electrical energy and works on faradays law of electromagnetic induction [16]. it consists of a coil of wire which rotates in a magnetic field. according to faradays law, the emf is induced when the current-carrying conductor is placed in a magnetic field [17], the simple ac generator is shown in figure 2 [18]. the direction of induced emf is calculated through flemings simulation based analysis of single unit and parallel connected three phase ac generators in quest campus larkana (pp. 33 41) sukkur iba journal of emerging technologies sjet | vol. 5 no. 2 july – december 2022 35 right-hand rule, the process is repeated for each cycle [19] as shown in figure 3 [20]. it has been seen that at point a there is 00; no emf is generated because coil movement and direction of a magnetic field are in parallel with each other. at point b there is 900; maximum emf is generated because coil movement is at 900 to a magnetic field. at point c there is 1800; no emf is generated because coil movement and direction of a magnetic field are in parallel with each other. at point d there is 2700; maximum emf is generated because the coil movement is at 2700 to the magnetic field but opposite to point b. finally, at point a there is 3600; no emf is generated because coil movement and direction of a magnetic field are in parallel with each other and the coil completed the rotation [3]. assume that the coil shape is rectangular and has n no of turns with angular velocity ω and rotates in uniform magnetic field b and coil at any time is t then the angle between a magnetic field and coil time is given in equation (01) and magnetic field perpendicular to the plane of coil is given in equation (02) . θ = ωt(01) φ = bcosωt(02) when a magnetic field is linked with coil of 𝑁 turns then φ = bcosωta(03) where a is area of coil, induced emf in the coil according to faradays law 𝜀 = −𝑑∅ 𝑑𝑡⁄ 𝜀 = −𝑑(𝑁𝐵𝐴 cos 𝜔𝑡 𝑑𝑡⁄ 𝜀 = 𝑁𝐵𝐴𝜔 ǀ sin 𝜔𝑡(04) when coil is rotate with 900 then the value of 𝑠𝑖𝑛 is 1 then equation (04) becomes 𝜀0 = 𝑁𝐵𝑚 𝐴𝜔 = 𝑁𝐵𝑚 𝐴 2𝜋(05) where 𝐵𝑚 denotes the maximum flux density and a is the cross sectional area and f is the frequency of coil rotation, now add equation (05) in equation (04) then we get 𝜀 = 𝜀0𝑠𝑖𝑛𝜔(06) the induce current is given in equation (07) 𝐼 = 𝜀0 𝑅⁄ = 𝜀0𝑆𝑖𝑛𝜔(07) fig. 2. simple ac generator fig. 3. different positions of a coil simulation based analysis of single unit and parallel connected three phase ac generators in quest campus larkana (pp. 33 41) sukkur iba journal of emerging technologies sjet | vol. 5 no. 2 july – december 2022 36 fig 4 (a) fig 4(b) fig. 4. (a) salient pole rotor, (b) non-salient pole rotor ac generator is a very essential device that meets the requirement of electrical power in the shape of generation. in ac generators the slip rings are employed to produce the alternating current and are available in small and large capacities and mostly applied to the power plant for the generation of electrical power and in commercial and industrial sectors to meet the energy gap [21]. the main parts of the generator are the stator and rotor. the stator is a stationary part fixed an armature winding that carries the current for the load, it consists of a frame, stator core, and armature winding [22]. the rotor is the rotating part of the generator, it consists of magnetic field winding and a dc supply is used to magnetize the magnetic poles. salient and non-salient type rotors as shown in figures 4(a) and 4(b) are used depending on the point of application [23]. 3. parallel connections of ac generators when a load is increased beyond the capacity of a single unit of ac generator, another generator is connected in parallel to meet the required demand [11]. the single unit of large rating is heavy, large in size, and more costly to replace a single unit of small capacity with a large one and in case of fault the whole unit will be replaced with another one for maintenance, resulting in revenue loss, large labor charges and also disturb the reliability of power to run the offices, laboratories, and industries [24]. it is a dire need to connect a small rating of two ac generators in parallel to meet the required demand. if one unit of generator is faulty then we can run our major machines, laboratories, and office equipment till the availability of another unit safely [25]. two small units of parallel connected generators give result in small size, less weight, easy maintenance, and reduced revenue loss [26]. the parallel connection is possible when the terminal voltage of the two generators must be the same otherwise high current will flow between the two machines, resulting in damaging the equipment or generator [27]. the frequency of both generators must be the same otherwise the low-frequency generator takes more loads and results in the overloading of the generator [28]. the output voltage must be the same in phase otherwise large output voltage is developed in phase [29]. 4. parallel connected ac generators in quest campus larkana quest campus larkana was established in 2010. there are four engineering departments and initially, one batch was admitted in 2010 and installed a 50kva generator to meet the power demand in case of failure. after increasing the laboratories, staff offices, and induction of more student batches one more 50kva generator was added in simulation based analysis of single unit and parallel connected three phase ac generators in quest campus larkana (pp. 33 41) sukkur iba journal of emerging technologies sjet | vol. 5 no. 2 july – december 2022 37 parallel to meet the demand and run the load of 400amperes. fig. 5. parallel connected generators at quest campus larkana in case of low power requirement, only a single unit is running, and the other is remained off, this will give saving in consumption of fuel [11], so two small rating generators are beneficial instead of a single unit of large capacity which consumes a large amount of fuel, and large in size. figures 5 and 6 show the ac generators available at campus larkana. fig. 6. inner look of 50kva ac generator 5. simulation results and discussion the simulation model is developed in matlab software and analyzes the performance of the ac generator when operating alone and in parallel under normal and overload conditions. figure 7 shows the simulation model of parallel connected generators and table 1 shows the parameters of generators. table i. parametrs of ac generators s.no generator parameters value 1 capacity of ac generator 50 kva 2 output voltage per phase 220 volts 3 frequency 50 hz 4 inertia 3.7e3 5 pair of poles 2 nos 6 internal resistance of ac generator 0.0001 ohm 7 internal inductance of ac generator 0.05 henry 8 dc machine field type wound 9 armature resistance of dc machine 24 ohm 10 field resistance of dc machine 618 ohm 11 field inductance of dc machine 0.05 henry 12 field armature mutual inductance of dc machine 1.8 henry 13 initial field current of dc machine 0.3 ampere simulation based analysis of single unit and parallel connected three phase ac generators in quest campus larkana (pp. 33 41) sukkur iba journal of emerging technologies sjet | vol. 5 no. 2 july – december 2022 38 14 dc voltage source 169 volts 14 mechanical input speed 15 sampling time -1 fig. 7. simulation model of parallel connected two 50kva ac generator 5.1. single unit generator opearting alone (at 150 ampere load) in the initial stage, a load of quest campus larkana was 195 amperes and one single unit was sufficient to meet the supply gap. it has been seen in this simulation result from the single unit of generator produces the 220volts single phase without any oscillations and meets the requirement satisfactorily. figure 8 shows the simulation result of the generator under normal load conditions. 5.2. single unit generator opearting alone under variation of input and reference parameters (at 210 ampere load) when the load of the campus was increased beyond the capacity of a single generator, so it has seen in this simulation result that the output voltage of a single unit of the generator is reduced from 220volts to 170volts and not meets the requirement satisfactorily and after some time heat will be generated and shut down. figure 9 shows the simulation result of the generator under variation of input and reference parameters. 5.3. single unit generator opearting alone under variation of input and reference parameters (at 230 ampere load) when the load of the campus was increased beyond the capacity of a single generator i.e. up to 230amperes, so it has seen in this simulation result that the output voltage of a single unit of the generator is reduced from 220volts to 135volts and not meet the requirement satisfactorily and after some time heat will be generated and shut down. figure 10 shows the simulation result of the generator under variation of input and reference parameters. 5.4. two generator opearting parallel (at 320 ampere load) when the load was increased and to run the offices, labs, classes, and other loads satisfactorily, another generator of 50kva was added to the first generator in parallel. it has been seen in this simulation result that the parallel operation of two generators share the load and produces the 220volts single phase and meets the requirement satisfactorily. figure 11 shows the simulation result of the parallel operation of two generators. fig. 8. single unit operation of generator under normal input and reference parameters simulation based analysis of single unit and parallel connected three phase ac generators in quest campus larkana (pp. 33 41) sukkur iba journal of emerging technologies sjet | vol. 5 no. 2 july – december 2022 39 fig. 9. single unit operation of generator under variation of input and reference parameters fig. 10. single unit operation of generator under normal input and reference parameters fig. 11. parallel operation of two ac generators 5.5. discussion it has been seen from the literature that the power crises are increasing day by day in pakistan due to that our industrial sectors, public sector, and commercial sectors are facing very difficulty in keeping the reliable operation of their equipment. the solar system is more costly and difficult to get energy at the night time. so an ac generator is the best option to meet the energy gap in day and night time. it has been seen from simulation results that the performance of a single-unit generator is not satisfactory under overload conditions and consumers received less voltage for utilization and the generator overheated and shut down. to eliminate this problem another generator of the same rating is connected in parallel to get the satisfactory performance of generators under overload conditions. table 2 shows the simulation results of the operation of ac generators operating alone and in parallel. table ii. simulation results of ac generators operating in parallel and alone load single unit generator parallel connected generators 150 ampere 220 volts per phase operation not started 210 ampere 170 volts per phase operation not started 230 ampere 135 volts per phase operation not started 320 ampere ---220 volts per phase 6. conclusion this research study is carried out in the quaid-e-awam university of engineering and technology nawabshah campus larkana to analyze the performance of the single unit generator and parallel connection of two generators to meet the energy demand in case of failure of the power supply. in pakistan, the energy demand is increasing day by day, and currently facing a shortage of energy due to that 6-8 hours load shedding is carried out in cities and 12-14 hours in villages. hospitals, laboratories, industries, commercial loads, and universities are very responsive places so the availability of electrical power is essential to carry out the work properly. for the simulation based analysis of single unit and parallel connected three phase ac generators in quest campus larkana (pp. 33 41) sukkur iba journal of emerging technologies sjet | vol. 5 no. 2 july – december 2022 40 continuity of power supply stand-by system is necessary in shape of ac generators because the solar system will be affected in the rainy season, cloudy conditions, and nighttime. the two generators of 50kva are available in quest campus larkana to meet the required energy gap. it has been seen from the simulation results that when a load is increased beyond the capacity of a single unit of the generator then the output voltage is decreased and the generator is overheated after some time generator is shut down, so it is necessary to add another generator in parallel with a single one to share the load. the output voltage remains within the limit and the problem of overheating and shutdown is eliminated. singe large unit of generator is costly and heavy and also a problem in maintenance, so it is concluded that the two generators of small capacity are installed, resulting in easy maintenance, reduce cost, and small in size to meet the energy demand in industries, hospitals, universities, and laboratories. acknowledgment the authors would like to thank quest, nawabshah pakistan and muet, jamshoro pakistan for the research facility provided. funding this research is without any external funding references [1] m. a. raza, k. l. khatri, a. israr, m. i. u. haque, m. ahmed, k. rafique, et al., "energy demand and production forecasting in pakistan," energy strategy reviews, vol. 39, p. 100788, 2022. [2] f. arshad and m. shamshad, "energy crisis in pakistan: socio-economic implications and the way forward," annals of social sciences and perspective, vol. 3, pp. 105-115, 2022. [3] h. radmanesh, h. jashnani, a. khaledian, and h. sobhani, "optimal and stable electric power system for more electric aircraft: parallel operation of generators and weight reduction," journal of energy management and technology, vol. 5, pp. 23-31, 2021. [4] g. d. valasai, m. a. uqaili, h. r. memon, s. r. samoo, n. h. mirjat, and k. harijan, "overcoming electricity crisis in pakistan: a review of sustainable electricity options," renewable and sustainable energy reviews, vol. 72, pp. 734-745, 2017. [5] b. singh, a. chandra, and k. al-haddad, power quality: problems and mitigation techniques: john wiley & sons, 2014. [6] a. farooqi, m. m. othman, m. a. m. radzi, i. musirin, s. z. m. noor, and i. z. abidin, "dynamic voltage restorer (dvr) enhancement in power quality mitigation with an adverse impact of unsymmetrical faults," energy reports, vol. 8, pp. 871-882, 2022. [7] r. adware and v. chandrakar, "comprehensive analysis of statcom with svc for power quality improvement in multi machine power system," in 2022 2nd international conference on power electronics & iot applications in renewable energy and its control (parc), 2022, pp. 15. [8] v. khare, s. nema, and p. baredar, "solar– wind hybrid renewable energy system: a review," renewable and sustainable energy reviews, vol. 58, pp. 23-33, 2016. [9] a. chauhan and p. thakur, power quality issues and their impact on the performance of industrial machines: anchor academic publishing, 2016. [10] i. boldea, "electric generators and motors: an overview," ces transactions on electrical machines and systems, vol. 1, pp. 3-14, 2017. [11] m. stone, "parallel operation of ac generators—action of governors and damper windings," electrical engineering, vol. 52, pp. 44-44, 1933. [12] g. j. herbert, s. iniyan, e. sreevalsan, and s. rajapandian, "a review of wind energy technologies," renewable and sustainable energy reviews, vol. 11, pp. 1117-1145, 2007. [13] z. yao, z. yuxing, k. yaqian, and b. sobhani, "research on an integrated power and freshwater generation system from natural gas energy and geothermal sources," desalination, vol. 525, p. 115494, 2022. [14] m. asim, s. jamil, r. shad, n. hayat, a. moaz, m. t. akram, et al., "comparison of reanalysis, analysis and forecast datasets with measured wind data for a wind power project in jhimpir, pakistan," in journal of physics: conference series, 2018, p. 012004. [15] m. s. sarfraz, m. asim, m. s. kamran, s. imran, and n. hayat, "evaluation of erainterim and ncep-cfsr reanalysis datasets against in-situ measured wind speed data for keti bandar port, pakistan," in journal of physics: conference series, 2018, p. 012001. [16] j. darke, "the primary generator and the design process," design studies, vol. 1, pp. 3644, 1979. [17] t. chan, l. lai, and l.-t. yan, "performance of a three-phase ac generator with inset ndfeb permanent-magnet rotor," ieee transactions on energy conversion, vol. 19, pp. 88-94, 2004. [18] m. d. lee, p. san lee, r. c. h. chiong, p. karunakaran, and h. j. ngu, "design and development of a small-scale mechanical energy conversion device," in 2020 ieee international conference for innovation in technology (inocon), 2020, pp. 1-5. simulation based analysis of single unit and parallel connected three phase ac generators in quest campus larkana (pp. 33 41) sukkur iba journal of emerging technologies sjet | vol. 5 no. 2 july – december 2022 41 [19] s. singirikonda, g. sathishgoud, and m. harikareddy, "transient stability of ac generator controlled by using fuzzy logic controller," int j eng res appl, vol. 4, 2014. [20] i. boldea, the electric generators handbook2 volume set: crc press, 2005. [21] h. polinder, j. a. ferreira, b. b. jensen, a. b. abrahamsen, k. atallah, and r. a. mcmahon, "trends in wind turbine generator systems," ieee journal of emerging and selected topics in power electronics, vol. 1, pp. 174-185, 2013. [22] c. williams and r. b. yates, "analysis of a micro-electric generator for microsystems," sensors and actuators a: physical, vol. 52, pp. 8-11, 1996. [23] w. freitas, a. morelato, w. xu, and f. sato, "impacts of ac generators and dstatcom devices on the dynamic performance of distribution systems," ieee transactions on power delivery, vol. 20, pp. 1493-1501, 2005. [24] l. larson, "parallel operation of aircraft ac generators," transactions of the american institute of electrical engineers, part ii: applications and industry, vol. 72, pp. 403407, 1954. [25] l. dreller, "the fundamentals of parallel operation of direct and alternating current generators," journal of the american society of naval engineers, vol. 49, pp. 273306, 1937. [26] v. popov, "ac generator paralleling method," 2020. [27] o. honorati, f. caricchi, and e. santini, "high speed ac generator (7200 rpm, 60 hz) for autonomous power systems," ieee transactions on energy conversion, vol. 4, pp. 544-550, 1989. [28] a. arkadan, y. abou-samra, and n. alaawar, "characterization of stand alone ac generators during no-break power transfer using radial basis networks," ieee transactions on magnetics, vol. 43, pp. 18211824, 2007. [29] x. liu, p. c. loh, f. blaabjerg, and p. wang, "load sharing using droop control for parallel operation of matrix converters as distributed generator interfaces in isolated mode," in 2012 ieee energy conversion congress and exposition (ecce), 2012, pp. 962-968. format template vol. 4, no. 1 | january june 2021 sjet | p-issn: 2616-7069 |e-issn: 2617-3115 | vol. 4 no. 1 january – june 2021 1 a deep learning based noninvasive and real-time fault detection system for 3phase induction motors muhammad abdullah faheem1, dileep kumar soother2, bharat lal harijan1, jotee kumari1, and areesha qureshi1 abstract: induction motor (im) plays a major role in industry. despite of its strong structure, ims are often prone to faults. there are different types of faults which occur in induction motors such as bearing faults, rotor bar faults, winding faults, etc. thus, motors in major applications require continuous and effective monitoring. in this paper, a stand-alone and non-invasive condition monitoring system is developed that can monitor the condition of 3-phase im using motor current signature data with aid of deep learning (dl) approaches. the proposed system acquires the data using non-invasive current sensors then converts the acquired data to digital data using an analog to digital converter (adc), and saves the acquired data in files. the raw current data acquired from induction motor is used to train the dl models including multilayer perceptron (mlp), long short-term memory (lstm), and one-dimensional convolutional neural networks (1d-cnn). the comparative analysis demonstrated the lstm model as the best fault classifier among the comparative dl models with the accuracy up to 100% owing to its deep hierarchical structure. at the end, the real-time testing of the device is performed which confirms that the developed system can effectively monitor the motor using non-invasive current sensors and dl models. keywords: deep learning; current sensors; non-invasive; fault detection; induction motor 1. introduction three phase induction motors (ims) have been widely employed in various industries including railways, aeronautics, petrochemical, gas plants, and automotive industry [1, 2]. according to the research reports the power consumption by induction motor in the industries is about 60% of total power generated by any country [3, 4], which implies that ims are an essential part of industry [5, 6]. among various types of motors, the squirrel cage motors have been widely used in industrial applications owing to its reliable operation and cost-effectiveness. the proper function of the motor is of high priority, once it becomes faulty, it costs a fortune. bearings are the most vulnerable part of ims that causes serious damages to motors. 1 department of electronic engineering, mehran uet jamshoro, sindh, pakistan 2 ncra condition monitoring systems lab, mehran uet jamshoro, sindh, pakistan corresponding author: dileepkalani1994@gmail.com mailto:dileepkalani1994@gmail.com m. a. faheem (et al.), a deep learning based non-invasive and real-time fault detection system for 3-phase induction motors (pp. 1 11) sukkur iba journal of emerging technologies sjet | vol. 4 no. 1 january – june 2021 2 if any fault is left unnoticed it may cause major damages to rotating machinery, which in turn costs huge amount of money for repairing and eventually it causes process to halt [7, 8]. thus, early fault detection in rotating machines is a goal that ultimately assists in saving system from major damages generally, a motor requires electric current for rotor to produce torque, which is obtained by electromagnetic induction from magnetic field of stator winding. in various industries 3phase ims are widely used because these motors are efficient, reliable, compact, less expensive, and easy to operate [6, 9]. three phase motors are also used in electric vehicles and railways owing to its robust structure and high performance [10]. manufacturers over the years are trying to build reliable motors; yet they pose many types of faults which cause huge losses and downtime. therefore, condition monitoring of motors is essential in almost every industry. further, condition monitoring can be done through various methods such as vibration, current, voltage, temperature, and sound analysis of a machine to detect various faults. among these methods, motor current signature analysis (mcsa) have been widely employed to monitor condition of ims. as this sensing method provides highly sensitive information relating to behavior of motors. thus, it is used for condition monitoring of heavy industrial machinery [11]. the current analysis method is also helpful in effective fault detection of three phase ims. deep learning (dl) as an advance version of artificial intelligence and hierarchically learns representations even from raw data through employing multiple layers in different architectures [12]. it has become hotspot for researchers as an effective solution for health monitoring systems. it has been evolving with the flow of time in terms of capabilities. various dl architectures have been successfully utilized for effective and reliable condition monitoring of industrial system including multilayer perceptron (mlp), autoencoders, convolutional neural networks (cnn), recurrent neural networks (rnn), and generative adversarial networks (gan) [13, 14]. however, dl methods can address bigscale data through its multi-level architectures. long short-term memory (lstm) is an upgraded version of rnn, capable of learning long term dependencies and the most popular solution to the gradient vanishing problem. recent researches have employed current signature data with different analysis methods for motor fault detection and classification task. in this context, c. morales-perez, et al. [15] have proposed sparse representations and dictionary learning based technique with the motor current data to detect bearing faults. the 3-phase motor was operated under two load conditions. the sparse representations allowed to limit the reconstruction error of the method which in turn increased the detection accuracy up to 96.94%. in [16] authors have used cnn with current signature data for broken rotor bar (brb) fault detection. they have used notch filter to get rid of the fundamental frequency and then applied short time fourier transform (stft) on transient current data. subsequently, the data was transformed into the images of five different sizes and then fed to the model for representations learning. the method was able to automatically detect different severity levels of broken rotor bar fault with the accuracy up to 100%. however, the method demonstrated slow response during fault detection owing to the pre-processing of the data. authors of [17] have used lstm with empirical mode decomposition (emd) combined with correlation analysis and wavelet threshold de-noising for bearing fault classification. the lstm model was fed with the signal components obtained from maximum correlation of emd. the results demonstrated that the method was able to effectively classify the bearing faults with the 97.84% accuracy. in this paper, a non-invasive and end-toend fault diagnosis system is proposed. the system is developed using the current signature analysis and dl models. different form aforementioned researches, we propose a method to effectively detect and identify faults of the motor in real-time through a noninvasive current sensing method. the end-toend automatic fault diagnosis system is developed using dl methods. remaining m. a. faheem (et al.), a deep learning based non-invasive and real-time fault detection system for 3-phase induction motors (pp. 1 11) sukkur iba journal of emerging technologies sjet | vol. 4 no. 1 january – june 2021 3 paper is organized as follows: section 2 discusses the current signature analysis and its importance, section 3 explains components used in this research, section 4 discusses the methods used in this investigation, section 5 reports and discusses the results, and section 6 concludes this paper. 2. current signature analysis induction motors are prone to various electrical and mechanical faults due to various reasons such as harsh environment, overloading, and improper power supply [18, 19]. these faults are diagnosed using different signatures such as vibration, current, temperature, etc. among these methods, current signature have been employed by researchers as an effective method even for mechanical fault diagnosis. mechanical faults such as bearing faults in motor generates spurious frequency which are reflected in the stator’s current spectrum as given in eq. (1). thus, different mechanical faults of the motor can be detected using current signature analysis [15]. 𝐹𝑖𝑠 = |𝐹𝑠 ± 𝑘𝐹𝑣| (1) where, fis represents spurious frequency, fs is the frequency of the power supply, fv characteristic frequency of the fault and k ∈ ℕ. moreover, non-invasive current signature analysis have multiple advantages including easy implementation, inexpensiveness, and no interference with other signals of motor [4]. thus, it is has been point of attention for the researchers in this domain. 3. system components this section consists of discussions of all the components used to develop this condition monitoring system, and each component is described as under: 3.1. sensors to acquire 3-phase current data from the im three sct-013-005 current sensors are used as shown in fig. 1. the sct-013-005 is a non-invasive current sensor that works on the principles of a transformer and manufactured by the beijing yaohuadechang electronic co., ltd (yhdc). when the primary coil is fed with an input voltage, magnetic flux is produced and it induced voltage in the secondary coil of transformer, the same phenomenon is followed by the sct-013-005 current sensor. however, this sensor has only one coil in its internal structure that works as secondary coil and its primary coil is the live phase wire of the im [20]. fig. 1. clamp type current sensor [20] since, it is used for a 3-phase induction motor that is why each phase require a current sensor, to fulfill this condition three sct-013005 current sensors are installed on the each phase of the im. the specifications of the sensor are given in table i. table i. specifications of the current sensor [4] s. no. metrics description 1. opening size 13*13mm 2. non-linearity ±3% ±3% 3. di-electric strength 1000v ac/1min 4. operating temperature 25℃ to +70℃. 5. input current 0-5a 6. output voltage 0-1v an analog to digital converter (adc) is used for the interfacing between analog current sensor and raspberry pi microcomputer. as the output of current sensors is analog, the raspberry-pi supports digital data. thus, to resolve this problem a 16 bit, 4-channel adc, ads1015 is employed with three current sensors. the adc is able to convert only 100 samples per second simultaneously of the three channels. m. a. faheem (et al.), a deep learning based non-invasive and real-time fault detection system for 3-phase induction motors (pp. 1 11) sukkur iba journal of emerging technologies sjet | vol. 4 no. 1 january – june 2021 4 however, increase in the sampling rate causes data loss. 3.2. raspberry-pi raspberry pi is developed and distributed by the raspberry pi foundation. it is a standalone board, which was developed for prototyping and development of embedded systems. it has been widely used by professionals and hobbyists in various application systems like robotics, condition monitoring, object recognition systems, etc. there are several models available for raspberry pi. the model used in this project is the raspberry pi 4b. it supports the linux based operating system. the specifications of the raspberry pi 4 b are mentioned in table ii [22]: table ii. raspberry pi specifications [22] s. no. metrics description 1. cpu 1.5 ghz quad-core a72 64-bits 2. ram 4 gb 3. storage micro-sd slot (expandable) 4. power 5v, 3a (type-c cable) 5. operating system linux the results of the developed system are displayed by interfacing a 7-inch touch screen display with the raspberry-pi microcomputer. the resolution of the 7-inch lcd display is 1024*600 pixels. 3.3. three phase induction motor for development of the proposed system, a 3phase squirrel cage im is used. it has the following specifications given in table iii: 4. methodology to develop a stand-alone fault detection system different components are used including the induction motor, current sensors, analog to digital convertor, and raspberry-pi board. the non-invasive current sensors are used to acquire the data from the induction motor and provide analog signal output. since, the current sensor provide analog output that is why adc is interfaced with it to convert the analog data into digital form to save it to the raspberry-pi microcomputer. the data acquisition system will store the data in a comma separated value (csv) file for training the dl models. then the acquired data is further split into the ratio of 7:2:1 as training, test, and validation set, respectively. following dl models are employed in this research for fault detection and comparison of performance on the acquired data. fig. 2 shows the block diagram of the method employed in this research. table iii. motor specifications s. no. metrics value 1. power rating 0.5 h.p. 2. rpm 1450 3. current rating 3a 4. phase 3 4.1. lstm lstm is an upgraded version of rnn, capable of learning long term dependencies. remembering information for long period of time is in its default behavior. lstm network is the most popular solution to the vanishing gradient problem. table iv shows the structure of the model and the distribution of layers in the model is described below: • lstm corresponds to the input and the hidden layers. • dropout is a regularization technique that is used to ignore certain set of neurons during the training stage. • dense corresponds to the output layer. m. a. faheem (et al.), a deep learning based non-invasive and real-time fault detection system for 3-phase induction motors (pp. 1 11) sukkur iba journal of emerging technologies sjet | vol. 4 no. 1 january – june 2021 5 3-phase motor current data acquisition analog to digital conversion deep learning model training real-time testing of the developed system fig. 2. system block diagram table iv. structure of the lstm model layer type units lstm 128 lstm 64 lstm 32 dropout 0.2 sigmoid function 2 4.2. mlp mlp is a fundamental dl model. it is a type feed forward artificial neural networks that uses a supervised technique called ‘back propagation’ for training process. it has multiple layers that make it different from the linear perception. the linearly inseparable data can be classified using mlp deep learning model. in table v there are 6 layers in which: • dense layers corresponds to the hidden layer. table v. structure of the mlp model layer type units dense 64 dense 64 dense 32 dense 32 dense 16 dropout 0.2 sigmoid function 2 4.3. 1d-cnn 1d-cnn is used for time series or sequential data which tends to slide the kernel is one dimension only. the 1d-cnn takes 1-dimensional input data and provides 1-dimensional output data against it. table vi shows the structure of the model. table vi. structure of the 1d-cnn model layer type units conv1d 128 conv1d 128 max-pool 128 conv1d 64 conv1d 64 dropout 0.2 flatten 64 dense 100 sigmoid function 2 primarily, the parameters that are used for the training of each dl model are: • batch size = 64 • no. of samples = 2,50,000 • no. of iterations = 1000 • learning rate = 0.000001 • data split = 70:20:10 as training data, validation data, and cross validation or testing data. generally, to train any dl model, the data is divided into three sections i.e. training set, testing or cross validation set, and the testing set. the training data set is used to train the algorithm. the validation data set is used to tune parameters of the model and the test data set is used for prediction and for obtaining the performance characteristics i.e. accuracy of the model. the work flow of the real-time fault classification system is shown in fig. 3. 5. results and discussions the performance of the dl models is evaluated on the basis of accuracy, precision, recall, and f1-score. formulas of these performance indexes are given as under [23]: accuracy = tp + tn tp + tn + fp + fn (2) precision = tp tp + fp (3) recall = tp tp + fn (4) m. a. faheem (et al.), a deep learning based non-invasive and real-time fault detection system for 3-phase induction motors (pp. 1 11) sukkur iba journal of emerging technologies sjet | vol. 4 no. 1 january – june 2021 6 f1‒ score = 2( recall ∗ precision recall + precision ) (45) where, (i). tp = the classifier’s predicted value was true, and the real value was also true. (ii). tn = the classifier’s predicted value was false, and the real value was false. fig. 1. workflow diagram of the real-time fault detection system m. a. faheem (et al.), a deep learning based non-invasive and real-time fault detection system for 3-phase induction motors (pp. 1 11) sukkur iba journal of emerging technologies sjet | vol. 4 no. 1 january – june 2021 7 (iii). fp = the classifier’s predicted value was true, and the real value was false. (iv). fn = the classifier’s predicted value was false, and the real value was also true. in this paper, a comparison of three dl models is provided. in comparison with the other two dl models, lstm model provided 100% accurate results in predicting condition of the im. the training and testing accuracy obtained from each dl model is presented in table vii. it can be observed from the table that the lstm model has demonstrated best results among all the three dl models on the provided dataset and the set hyperparameters. table vii. training & testing accuracies of three compared models table head lstm mlp 1d-cnn training accuracy 100% 86% 94.52% testing accuracy 100% 85.8% 93.50% a confusion matrix is a technique used for summarizing or describing the performance of machine learning or deep learning models. it is kind of a table describing the number of correct and incorrect predictions made by a model. the confusion matrices for each of the dl model used in this research are described in fig. 4. it can be observed from fig. 4(a) that in the confusion matrix of lstm model none of the prediction is incorrect, while for the other models certain predictions are incorrect. it can be summarized that the lstm model provides the best accuracy among all other models. the classification report of these models is shown in table viii. from the table, it can be concluded that lstm has higher precision, recall and f1-score among all. fig. 3. confusion matrices of (a)lstm, (b)mlp, and (c) 1d-cnn the loss and accuracy graphs of lstm, mlp and 1d-cnn are given in fig. 5. these graphs were obtained during training process of the dl models. from the graphs shown under, it can be concluded that in graph (a) when epochs reach at 1000, the accuracy of the lstm model is 100% and the loss falls to almost 0%. furthermore, the lstm model shows most stable response among the employed models. while in graph (b) and graph (c) when epochs reach at 1000 the accuracy is less than 100% and the loss increases. moreover, response of the mlp and 1d-cnn model keeps fluctuating during the training process. thus, lstm model can be (a) (b) (c) m. a. faheem (et al.), a deep learning based non-invasive and real-time fault detection system for 3-phase induction motors (pp. 1 11) sukkur iba journal of emerging technologies sjet | vol. 4 no. 1 january – june 2021 8 referred to as the best model amongst the employed dl models. the final prototype of standalone motor condition monitoring system is in shown in the fig. 6. overall, the developed demonstrated effective performance. however, the system posed problem in data acquisition owing to low processing power of the raspberry-pi model 4b. table viii. classification report of three compared models table head precision recall f1-score lstm healthy 1.00 1.00 1.00 faulty 1.00 1.00 1.00 mlp healthy 0.85 0.83 0.84 faulty 0.86 0.88 0.87 1d-cnn healthy 1.00 0.85 0.92 faulty 0.89 1.00 0.94 (a) m. a. faheem (et al.), a deep learning based non-invasive and real-time fault detection system for 3-phase induction motors (pp. 1 11) sukkur iba journal of emerging technologies sjet | vol. 4 no. 1 january – june 2021 9 fig. 4. loss and accuracy graphs of (a) lstm, (b), mlp, and (c) 1d-cnn (b) (c) fig. 2. standalone real-time motor condition monitoring system m. a. faheem (et al.), a deep learning based non-invasive and real-time fault detection system for 3-phase induction motors (pp. 1 11) sukkur iba journal of emerging technologies sjet | vol. 4 no. 1 january – june 2021 10 6. conclusion this paper reported a non-invasive condition monitoring device for 3-phase im based on current signature data and dl models. the developed device is a real-time fault diagnosis system that detects and classify the status of the motor through the provided input data. the current data is acquired using clamp type noninvasive current sensors, an adc, and raspberry-p. the comparative analysis among the three dl models including lstm, mlp, and 1d-cnn. the results confirmed the lstm model as the best model. moreover, the developed system is stand-alone and noninvasive that can be clamped on any 3-phase im to detect its bearing faults in real-time by using the 3-phase current data and the lstm classifier. the output results are displayed on a 7-inch touch screen lcd display, the user can interactively monitor the developed system using the touch-screen display. the compact size and portability of the developed system makes it easy for user to deploy it on any motor. the extended version of this system can be deployed on industrial motors for effective condition monitoring. the developed system has a limitation of data acquisition at low sampling rate. the system was only able to acquire simultaneous data from three sensors at the rate of 100 samples per second. in future, the limitation can be addressed by using high performance data acquisition board. data availabilty statement the datasets generated or analyzed during this study are not publically available because these datasets are the sole property of ncrahhcms lab, mehran uet jamshoro, sindh, pakistan. but, these datasets are available from the corresponding author on reasonable request and can be shared if permission is granted from the lab. conflict of interest authors of this paper declare no conflict of interest. funding this project is funded by the ‘ncra condition monitoring systems lab’ established in mehran university of engineering and technology, jamshoro under the umbrella of national center of robotics and automation project by the higher education commission (hec), pakistan. acknowledgment we acknowledge the support of the ‘ncra condition monitoring systems lab’ established in mehran university of engineering and technology, jamshoro under the umbrella of national center of robotics and automation funded by the higher education commission (hec), pakistan. references [1] n. lahouasnia, m. f. rachedi, d. drici, s. saad, and technology, "load unbalance detection improvement in three-phase induction machine based on current space vector analysis," journal of electrical engineering and technology, pp. 1-12, 2020. [2] m. s. moiz, s. shamim, m. abdullah, h. khan, i. hussain, a. b. iftikhar, et al., "health monitoring of three-phase induction motor using current and vibration signature analysis," in international conference on robotics and automation in industry (icrai), 2019, pp. 1-4. [3] w. r. s. osman, k. nisar, and a. m. altrad, "evaluation of broadband plc technology over malaysia's indoor power line network," in 2nd international conference on electronic design (iced), 2014, pp. 275-280. [4] h. khelfi and s. hamdani, "induction motor rotor fault diagnosis using three-phase current intersection signal," electrical engineering, vol. 102, pp. 539-548, 2020. [5] x. liang and k. edomwandekhoe, "condition monitoring techniques for induction motors," in ieee industry applications society annual meeting, 2017, pp. 1-10. [6] a. m. m. altrad, w. r. s. osman, and k. nisar, "modelling of remote area broadband technology over low voltage power line channel," international journal of computer networks & communications, vol. 4, p. 187, 2012. [7] a. choudhary, d. goyal, s. l. shimi, and a. akula, "condition monitoring and fault diagnosis of induction motors: a review," m. a. faheem (et al.), a deep learning based non-invasive and real-time fault detection system for 3-phase induction motors (pp. 1 11) sukkur iba journal of emerging technologies sjet | vol. 4 no. 1 january – june 2021 11 archives of computational methods in engineering, vol. 26, pp. 1221-1238, 2019. [8] a. glowacz, w. glowacz, j. kozik, k. piech, m. gutten, w. caesarendra, et al., "detection of deterioration of three-phase induction motor using vibration signals," vol. 19, pp. 241-249, 2019. [9] d. k. soother and j. daudpoto, "a brief review of condition monitoring techniques for the induction motor," transactions of the canadian society for mechanical engineering, vol. 43, pp. 499-508, 2019. [10] y. yuan, g. ma, c. cheng, b. zhou, h. zhao, h.-t. zhang, et al., "a general end-to-end diagnosis framework for manufacturing systems," vol. 7, pp. 418-429, 2020. [11] k. d. kompella, m. v. g. rao, and r. s. rao, "bearing fault detection in a 3 phase induction motor using stator current frequency spectral subtraction with various wavelet decomposition techniques," ain shams engineering journal, vol. 9, pp. 2427-2439, 2018. [12] r. palácios, w. godoy, a. goedtel, i. da silva, d. moríñigo-sotelo, and o. duque-perez, "time domain diagnosis of multiple faults in three phase induction motors using inteligent approaches," in 2017 ieee 11th international symposium on diagnostics for electrical machines, power electronics and drives (sdemped), 2017, pp. 85-89. [13] b. corne, b. vervisch, s. derammelaere, j. knockaert, and j. desmet, "the reflection of evolving bearing faults in the stator current’s extended park vector approach for induction machines," mechanical systems and signal processing, vol. 107, pp. 168-182, 2018. [14] s. namuduri, b. n. narayanan, v. s. p. davuluru, l. burton, and s. bhansali, "deep learning methods for sensor based predictive maintenance and future perspectives for electrochemical sensors," journal of the electrochemical society, vol. 167, p. 037552, 2020. [15] r. zhao, r. yan, z. chen, k. mao, p. wang, and r. x. gao, "deep learning and its applications to machine health monitoring," mechanical systems and signal processing, vol. 115, pp. 213-237, 2019. [16] g. toh and j. park, "review of vibrationbased structural health monitoring using deep learning," applied sciences, vol. 10, p. 1680, 2020. [17] c. morales-perez, j. rangel-magdaleno, h. peregrina-barreto, and j. ramirez-cortes, "bearing fault detection on im using mcsa and sparse representation," in ieee international instrumentation and measurement technology conference (i2mtc), 2020, pp. 1-6. [18] m. valtierra-rodriguez, j. r. rivera-guillen, j. a. basurto-hurtado, j. j. de-santiagoperez, d. granados-lieberman, and j. p. amezquita-sanchez, "convolutional neural network and motor current signature analysis during the transient state for detection of broken rotor bars in induction motors," sensors, vol. 20, p. 3721, 2020. [19] c. sun, j. xu, l. xu, g. wang, and y. xu, "research on locomotive motor bearing diagnosis method based on wavelet threshold denoising and correlation analysis combined with emd decomposition and lstm neural network," in 2020 chinese control and decision conference (ccdc), 2020, pp. 2770-2775. [20] g. h. bazan, p. r. scalassara, w. endo, a. goedtel, w. f. godoy, and r. h. c. palácios, "stator fault analysis of three-phase induction motors using information measures and artificial neural networks," electric power systems research, vol. 143, pp. 347-356, 2017. [21] d. k. soother, j. daudpoto, and a. shaikh, "vibration measurement system for the low power induction motor," engineering science and technology international research journal, vol. 2, pp. 53-57, 2018. [22] m. irfan, n. saad, r. ibrahim, v. s. asirvadam, n. m. nor, a. alwadie, et al., "a hardware and software integration approach for development of a non-invasive condition monitoring systems for motor-coupled gears faults diagnosis," in asian simulation conference, 2017, pp. 642-655. [23] t. instruments, "texas instruments," https://www.ti.com/product/ads1015. [last accessed: 22-jan-2021] [24] "raspberry pi 4b," https://www.raspberrypi.org/products/raspber ry-pi-4-model-b/.[last accessed: 22-jan2021] [25] h. dalianis, "evaluation metrics and evaluation," in clinical text mining, ed: springer, 2018, pp. 45-53. machine learning-based fake news detection with amalgamated feature extraction method vol. 5, no. 2 | july – december 2022 sjet | p-issn: 2616-7069 | e-issn: 2617-3115 | vol. 5 no. 2 july – december 2022 10 machine learning-based fake news detection with amalgamated feature extraction method muhammad bux alvi1*, majdah alvi1, rehan ali shah1, adnan akhter1, mubashira munir1, rakesh kumar2, kavita tabbassum3 abstract: product fake reviews are increasing as the trend is changing toward online sales and purchases. fake review detection is critical and challenging for both researchers and online retailers. as new techniques are introduced to catch the non-organic reviewer, so are their intruding approaches. in this paper, different features are amalgamated along with sentiment scores to design a model that checks the model performance under different classifiers. for this purpose, six supervised learning algorithms are utilized to build the fake review detection models, using liwc, unigrams, and sentiment score features. results show that the amalgamation of selected features is a better approach to counterfeit review detection, achieving an accuracy score of 88.76%, which is promising when compared to similar other work. keywords: fake reviews, machine learning, amalgamated features, liwc, sentiment score 1 introduction a fake review is a false judgment or an opinionated text on a product or a service. reviews can significantly affect the decision of buyers while shopping online. according to “statista” statistics, e-commerce sales increase 6% in america from 2013 to 2020 [1]. as online purchase increases, so is the competition of online retailer giants. therefore, the retailers and manufacturers take these reviews on a serious note. fake reviewers capitalize on this opportunity to artificially devalue or promote products and services [2][3]. hence, fake review prediction becomes a critical research area as online purchases increase. with the explosive growth of online businesses, the quantity and importance of reviews continue to increase. fake reviews severely threaten researchers [4] and online retailers [5]. reviews 1department of computer systems engineering, faculty of engineering, the islamia university of bahawalpur, pakistan 2freelancer and researcher 3department information technology center, sindh agriculture university tandojam, sindh, pakistan corresponding author: mbalvi@iub.edu.pk can be positive to increase purchases on an online platform by manipulating users with fake customer reviews. conversely, it can be a negative review to distract purchasers. it is estimated that 80% of users believe in posted product reviews before purchasing any product [6]. negative fake reviews are used to defame competitor’s reputations. people who post such fake reviews are usually freelancers, and companies hire their services for writing fake reviews. giant retailers like amazon find these fake reviews of severe threat to their reputation and filed a complaint against review spamming [7]. fake review prediction can be performed manually or automatically. research has been carried out on manual opinion spam prediction for several years [8]. early methods of fake review prediction were rudimentary. many texts mailto:mbalvi@iub.edu.pk machine learning-based fake news detection with amalgamated feature extraction method (pp. 10 17) sukkur iba journal of emerging technologies sjet | vol. 5 no. 1 january – june 2022 11 analysis-based approaches are found in the literature [9]. based on the research, commercial platforms developed opinion spam filtering systems to detect deceptive reviews. nevertheless, these systems make the fake reviewers enhance their review quality and deceive the detecting systems [10]. as time elapsed, those traditional approaches would not work efficiently because the fake reviewers started behaving like regular users. therefore, the trend of manual fake review prediction changed from text-based analysis to pattern and feature analysis like time [11], topics [12], ranking pattern [13], activity volume [14], and geolocation [15]. however, manual methods are slow, expensive, and of low accuracy. automated methods based on machine learning could also identify the opinion spams and spammers by analyzing the review features. text mining and natural language processing (nlp) work together to generate the concept of content mining, and review spam detection comes under this concept. additional review characteristics like review timings, reviewer id, and deviation trend of the review from other reviews of the same category are also considered in spam review detection. jindal et al.[16] used the machine learning technique and showed that the amalgam of features is more robust than a single feature for fake review prediction. li et al. in [17] showed that combining a bag of words (bow) with more general features performs better than bow alone. mukherjee et al. [18] used machine learning with abnormal behavioral features of the reviewers and depicted that this technique was better than the linguistic features-based technique. the significant contribution of this research is to develop a fake reviews detection model that uses machine learning techniques that will employ a heuristic optimization algorithm for affecting features and test its reliability and robustness against existing techniques. such a model, when employed, can benefit retailers and giant business companies to shield their businesses against fake reviews and reviewers. 2 literature review advancements have been made in fake review detection by introducing new techniques and methods by researchers. these techniques play their role in improving accuracy and performance. so far, reviews are marked as spam based on either review spam detection or reviewer spam detection. both techniques are helpful in fake review detection. prior deals with content mining and natural language processing (nlp), whereas later technique applied on reviewer id and his behavior. jindal et al. [16] is the first researcher who studied opinion spamming using supervised learning. the author divided the reviews into three categories (fake opinions, the brand only reviews, and non-review) and detected opinion spamming by finding duplicate reviews using the “w-shingling” method. the author used a dataset from amazon with more than 5 million product reviews, applied his devised technique with a logistic regression algorithm, and achieved an auc of 78%. lim, nguyen, jindal, liu, and lauw [19] proposed a behavioral methodology for revealing spammers for review. they tried to figure out some spammer habits like targeting goods and tried to optimize their effect. moreover, they suggested a model focused on specific patterns to identify rating spammers. ott et al. [20][21] created a data set for analysis in review spam detection. the data set comprised positive opinion spam with truthful reviews and negative opinion spam with real reviews. the author applied the ngram and linguistic features to find fake reviews under a supervised learning mechanism, and the results were verified with human performance. in their research, feng et al. [4] framed a model based on the normal distribution of opinion to detect fake reviews. in their view, a product or a service review involved this concept of normal distribution of opinion. shojaee et al. [9] suggested a novel technique for fake review detection by combining lexical and synthetic features. elmurngi and gherbi [22] proposed a text classification and sentimental analysis approach for different machine learning algorithms with stop words and without stop words. they also applied a machine learning-based fake news detection with amalgamated feature extraction method (pp. 10 17) sukkur iba journal of emerging technologies sjet | vol. 5 no. 1 january – june 2022 12 decision tree algorithm to improve their results. shah, ahsan, kafi, nahian, and hossain [23] combined supervised & active learning and created a model to detect spamming. both fictitious and real-life data were used for spam analysis. 3 proposed approach this section describes the proposed method to accomplish the task of fake review detection. this research uses two features as classification criteria with a sentiment score feature (an additional feature). these individual features and combinations are used to train various classifiers and tested against evaluation metrics. reviews are classified as fake or not fake. this study uses six classification algorithms: naive bayes, decision tree, instance-based knn, support vector machine (svm), logistic regression, and random forest. training data is 80%, and 20% of data is set aside for testing purposes with a 5-fold cross-validation technique. figure 1 presents the adopted research method for this work. 3.1 data acquisition and pre-processing the data set selected for this research contains 1600 reviews combined from two data sets (hotel review data sets). the data sets were created by myle et al. and are available from [20][21]. the data set contains eight hundred truthful reviews, of which four hundred are positive, and four hundred are negative. similarly, 800 spam reviews are also included in this data set, of which half are positive, and half are negative. the preprocessing of the data set significantly affects the accuracy of results [24][25][26]. furthermore, preprocessing curbs feature vector space. therefore, preprocessing techniques like missing values management, tokenization, stop words removal, and generating n-gram are implemented on the data set to obtain cleaner data set. 3.2 features features are pieces (s) of text that have semantic significance. in the text data systems, features highly influence the effectiveness of the developed model. fig. 1. proposed machine learning approach with amalgamated features for fake reviews detection 3.2.1 n-grams in this feature extraction method, n-adjacent tokens are picked as a feature from review contents. it is denoted as unigram if one adjacent word is selected, bigram if two adjacent words are selected, and trigram with three adjacent words at a time. these features can effectively help model all the content within the text. in this research work, unigram is used as a feature. machine learning-based fake news detection with amalgamated feature extraction method (pp. 10 17) sukkur iba journal of emerging technologies sjet | vol. 5 no. 1 january – june 2022 13 table i. state of art spam review detection techniques reference year data set learning type techniques/ algorithm results limitations [4] feng 2012 ott et al. data set with modification supervised learning libsvm classifier/ term frequency accuracy 72.5% specific kind of dataset [9] shojaee 2013 ott et al. data set supervised learning svm/ naïve bayes/ stylometric feature f-measure 84% limited to a specific domain [13] jindal n, liu b 2007 data set of the manufactured product only supervised learning logistic regression average auc 78% lack of accuracy of a real-world data set [18] lim, ee-peng 2010 amazon data set supervised learning behavioral features of spammer accuracy 78% limit set of data for supervised learning [20] jeffrey t. at el 2013 ott et al. data set supervised learning support vector machine (svm) accuracy 86 % human judgments can be imperfect and biased. [21] elmurngi e. 2017 movie review data set supervised learning dt(dt-j48)/ svm/knn accuracy 81.75% feature selection methods are not used [22] ahsan, nahian, kafi, hossain and shah 2017 ott dataset active/ supervised learning hybrid classifier using nb/ svc /dt /maximum entropy accuracy 95% small scale dataset is used for a specific domain 3.2.2 liwc the linguistic inquiry and word count (liwc) is a text analysis method. this method can analyze eighty different features, for example, psychological concerns like emotion, text functional aspects, and personal and perception concerns like religion [27]. 3.2.3 sentiment score it has been observed that spammers with negative reviews generally use more negative words like “bad” and “dissatisfied”. this way, the degree of negative sentiment is increased compared to a non-spam negative review. likewise, spammers with positive reviews generally use positive terms such as “good”, “great”, “nice”, and “gorgeous”. therefore, reviewers show more positive sentiment than a non-spam positive review. the sentiment score of a review can be calculated by the following formula [28]. machine learning-based fake news detection with amalgamated feature extraction method (pp. 10 17) sukkur iba journal of emerging technologies sjet | vol. 5 no. 1 january – june 2022 14 𝑆𝐶(𝑟𝑡) = ∑(−1)𝑛 𝑆(𝑊𝑖 ) 𝐷𝑖𝑠𝑡𝑎𝑛𝑐𝑒 (𝑓𝑒𝑡𝑖 𝑊𝑖 ) (1) where “rt” is review text, “s(wi)” is the sentiment polarity of word wi (+1 or -1), “n” denotes the total number of negation-words in a feature with default = 0, “fet” refers to a feature in a review sentence and “distance (fet, wi)” is the distance between feature and word. 3.3 classification algorithms six various classification algorithms are used in this paper in order to determine the effect of different features and their combinations on classification accuracy and performance. 3.3.1 naïve bayes (nb) nb is based on the bayes theorem [29]. it is a probabilistic multiclass classification algorithm assuming features independency to foresee the output class. equation 2 checks the probability of the feature-set being categorized into a particular class: 𝑃(𝑥) = 𝑃(𝑥1)𝑃(𝑥2)𝑃(𝑥3)𝑃(𝑥𝑛 ) (2) where “x = (x1,x2,…,xn)” are a set of features. individual probabilistic classification of a feature may be calculated as given in equation 3: 𝑃(𝑥) = 𝑝(𝐶𝑘 )𝑝(𝑥|𝐶𝑘 ) 𝑝(𝑥) (3) 3.3.2 decision tree (dt) the working principle of dt is based on a hierarchical breakdown of the data set used for training. in this classifier, features are used for labeling tree nodes, and the branches between them are given the weight representing the occurrence of feature in the test data; finally, class names are assigned to the leaf. the data set is divided into the presence or absence of features. the data set is divided recursively until the leaf nodes are reached. entropy formula: 𝐸𝑛𝑡𝑟𝑜𝑝𝑦 = − ∑ 𝑃𝑖𝑗 𝑙𝑜𝑔2𝑃𝑖𝑗 𝑚 𝑗=1 (4) 3.3.3 random forest (rf) rf is a voting method where many decision trees are grown simultaneously. the input features are fed to individual trees in the forest. the final classification is based on the overall most votes from all trees in the forest [30]. the mathematical form of random forest to calculate mean square error is: 𝑓 ^ = ∑ 1 𝑠 (𝑓𝑠 − 𝑦𝑠)2 𝑆 𝑠=1 (5) where "𝑆" denotes the number of data points, "𝑓𝑠" is the value returned by the model, and "𝑦𝑠" is the actual value of data points. 3.3.4 support vector machine (svm) svm is a classification algorithm that finds the maximum margin hyperplane to classify the “ith“ vector. optimal “y𝑖” (yi denotes the target), “𝑋𝑖” hyperplane is found by linear features between two classes (0 or 1). 3.3.5 k-nearest neighbor (knn) knn is an instance-based algorithm that assumes that similar things exist in close proximity. in this technique, the feature is classified by the plurality vote of its neighbors by calculating their distances. it uses euclidean distance formula to compute the distance between the points, which is mathematically represented as: 𝐷 = √∑(𝑥𝑖 − 𝑦𝑖 ) 2 𝑚 𝑖=1 (6) 3.3.6 logistic regression logistic regression is a model-based algorithm often used when the dependent variable is dichotomous in nature. however, it can be tuned to be used with multiclass classification tasks as well. logistic regression describes machine learning-based fake news detection with amalgamated feature extraction method (pp. 10 17) sukkur iba journal of emerging technologies sjet | vol. 5 no. 1 january – june 2022 15 the data set and defines the relationship between one dependent binary variable with one or more independent variables. 3.4 testing metrics accuracy, precision, recall, and f-score are used to evaluate model performance. these metrics can be defined as: 𝐴𝑐𝑐𝑢𝑟𝑎𝑐𝑦 = 𝑇𝑢𝑃 + 𝑇𝑢𝑁 𝑇𝑢𝑃 + 𝑇𝑢𝑁 + 𝐹𝑎𝑃 + 𝐹𝑎𝑁 (7) 𝑃𝑟𝑒𝑐𝑖𝑠𝑖𝑜𝑛 = 𝑇𝑢𝑃 𝑇𝑢𝑃 + 𝐹𝑎𝑃 (8) 𝑅𝑒𝑐𝑎𝑙𝑙 = 𝑇𝑢𝑃 𝑇𝑢𝑃 + 𝐹𝑎𝑁 (9) 𝐹 − 𝑆𝑐𝑜𝑟𝑒 = 2 ∗ (𝑟𝑒𝑐𝑎𝑙𝑙 ∗ 𝑝𝑟𝑒𝑐𝑖𝑠𝑖𝑜𝑛) (𝑟𝑒𝑐𝑎𝑙𝑙 + 𝑝𝑟𝑒𝑐𝑖𝑠𝑖𝑜𝑛) (10) where "tun", "tup", "fan", and "fap" are true negative, true positive, false negative, and false positive respectively. 4 experimental results, discussion and evaluation this section describes the experimental results, discusses the results, and evaluates the developed model quantitatively. six machine learning algorithms (naïve bayes, decision tree, random forest, svm, k-nearest neighbor, and logistic regression) were used to develop the model using three feature extraction techniques (liwc, n-gram (unigrams), and sentiment score). the results of individual feature and their combinations are shown in table 2. an accuracy of 63.22% is achieved when liwc is used alone, but when combined with a sentiment score, accuracy increases to 70.35%. classification model using unigram feature alone gives an accuracy of 73.55%, but if combined with sentiment score, it increases to 80.34%. maximum accuracy of 88.76% is attained by combining liwc, unigram, and sentiment scores. eventually, this study supports and proves the initial hypothesis of getting improved results by using amalgamated features with machine learning algorithm-based classification models. fig. 2. quantitative comparison with previous similar work 4.1 qualitative evaluation to strengthen the hypothesis, figure 2 shows the quantitative comparison of previous work [4][9][22] and the proposed method in this work to detect fake reviews using the hotel reviews dataset. it indicates that the undertaken work supersedes the other work. since a balanced dataset is used, the accuracy score measure is good enough for quantitative performance comparison of the developed machine learning algorithm-based models with previous work. this improvement is, at least, 4-5 points when compared with previous similar work. 5 conclusin this work was an effort to determine the effective combination of features that performs well for fake reviews detection. the study work used n-gram, liwc, and sentiment machine learning-based fake news detection with amalgamated feature extraction method (pp. 10 17) sukkur iba journal of emerging technologies sjet | vol. 5 no. 1 january – june 2022 16 score features for training purpose. different classifiers are trained on these features. the classification algorithms we chose are described in section 3.3. after experimental work, logistic regression outperformed all other machine learning algorithm-based models. as far as features performance is concerned, unigram proved to be better when applied in separation than liwc. however, the combination of both (unigram + liwc) with sentiment score performed more adequately, giving maximum accuracy of 88.76%. this result is better than some other techniques described in section 2. for future work, it is suggested to use semi-supervised learning to check the accuracy and performance of unigram and liwc features on the fake review detection method. in this way, possible performance enhancement will be measured. at the same time, the limitation of the labeled data set for supervised learning will also be resolved. table ii. performance evaluation of different feature extraction methods approaches (features) maximum accuracy (%) precision recall f-score liwc 63.22 58.00 64.43 61.05 sentiment score, liwc 70.35 62.50 73.88 67.71 unigram 73.55 78.00 74.50 76.21 sentiment score, unigram 80.34 91.50 77.59 83.97 sentiment score, liwc, unigram 88.76 92.00 82.61 87.05 references [1] “• u.s. e-commerce share of retail sales 2021-2025 | statista.” https://www.statista.com/statistics/379112/e-commerce-share-of-retailsales-in-us/. [2] f. li, m. huang, y. yang, and x. zhu, “learning to identify review spam,” ijcai int. jt. conf. artif. intell., pp. 2488–2493, 2011, doi: 10.5591/978-157735-516-8/ijcai11-414. [3] r. y. k. lau, s. y. liao, r. chi-wai kwok, k. xu, y. xia, and y. li, “text mining and probabilistic language modeling for online review spam detection,” acm trans. manag. inf. syst., vol. 2, no. 4, dec. 2011, doi: 10.1145/2070710.2070716. [4] s. feng, l. xing, a. gogar, and y. choi, “distributional footprints of deceptive product reviews,” icwsm 2012 proc. 6th int. aaai conf. weblogs soc. media, pp. 98–105, 2012. [5] sussin, j., and e. thompson, “the consequences of fake fans,’likes’ and reviews on social networks,” gart. res., vol. 2091515, 2012. [6] “amazon sues to block alleged fake reviews on its website | reuters.” https://www.reuters.com/article/us-amazon-comlawsuit-fake-reviews-iduskbn0n02lp20150410 . [7] “local consumer review survey 2022: customer reviews and behavior.” https://www.brightlocal.com/research/localconsumer-review-survey/ . [8] n. spirin and j. han, “survey on web spam detection : principles and algorithms,” vol. 13, no. 2, pp. 50–64. [9] n. m. s. and s. n. somayeh shojaee, masrah azrifah azmi muradt, azreen bin azman, “detecting deceptive reviews using lexical and syntactic features,” pp. 219–223, 2013. [10] y. yao, b. viswanath, j. cryan, h. zheng, and b. y. zhao, “automated crowdturfing attacks and defenses in online review systems,” proc. acm conf. comput. commun. secur., pp. 1143–1158, 2017, doi: 10.1145/3133956.3133990. machine learning-based fake news detection with amalgamated feature extraction method (pp. 10 17) sukkur iba journal of emerging technologies sjet | vol. 5 no. 1 january – june 2022 17 [11] k. c. santosh and a. mukherjee, “on the temporal dynamics of opinion spamming: case studies on yelp,” 25th int. world wide web conf. www 2016, pp. 369–379, 2016, doi: 10.1145/2872427.2883087. [12] s. nilizadeh et al., “poised: spotting twitter spam off the beaten paths,” dl.acm.org, pp. 1159–1174, oct. 2017, doi: 10.1145/3133956.3134055. [13] h. chen, “toward detecting collusive ranking manipulation attackers in mobile app markets,” pp. 58–70, 2017. [14] d. y. t. chino, a. f. costa, a. j. m. traina, and c. faloutsos, “voltime: unsupervised anomaly detection on users’ online activity volume,” proc. 17th siam int. conf. data mining, sdm 2017, pp. 108–116, 2017, doi: 10.1137/1.9781611974973.13. [15] r. deng, n. ruan, r. jin, y. lu, and w. jia, “spamtracer : manual fake review detection for o2o commercial platforms by using geolocation features,” pp. 1–20. [16] n. jindal and b. liu, “review spam detection,” 16th int. world wide web conf. www2007, pp. 1189–1190, 2007, doi: 10.1145/1242572.1242759. [17] j. li, m. ott, c. cardie, and e. hovy, “towards a general rule for identifying deceptive opinion spam,” pp. 1566–1576, 2014. [18] a. mukherjee, v. venkataraman, … b. l.-s. international a., and u. 2013, “what yelp fake review filter might be doing?,” proc. int. aaai conf. web soc. media, vol. 7, no. 1, pp. 409–418, 2011. [19] b. liu and h. w. lauw, “detecting product review spammers using rating behaviors,” pp. 939–948, 2010. [20] m. ott, y. choi, c. cardie, and j. t. hancock, “finding deceptive opinion spam by any stretch of the imagination,” acl-hlt 2011 proc. 49th annu. meet. assoc. comput. linguist. hum. lang. technol., vol. 1, pp. 309–319, 2011. [21] m. ott, c. cardie, and j. t. hancock, “negative deceptive opinion spam,” naacl hlt 2013 2013 conf. north am. chapter assoc. comput. linguist. hum. lang. technol. proc. main conf., no. june, pp. 497–501, 2013. [22] e. elmurngi and a. gherbi, “an empirical study on detecting fake reviews using machine learning techniques,” 7th int. conf. innov. comput. technol. intech 2017, no. intech, pp. 107–114, 2017, doi: 10.1109/intech.2017.8102442. [23] m. n. i. ahsan, t. nahian, a. a. kafi, m. i. hossain, and f. m. shah, “an ensemble approach to detect review spam using hybrid machine learning technique,” 19th int. conf. comput. inf. technol. iccit 2016, pp. 388–394, 2017, doi: 10.1109/iccitechn.2016.7860229. [24] w. etaiwi and g. naymat, “the impact of applying different preprocessing steps on review spam detection,” procedia comput. sci., vol. 113, pp. 273–279, 2017, doi: 10.1016/j.procs.2017.08.368. [25] m. b. alvi, n. a. mahoto, m. a. unar, and m. a. shaikh, “an effective framework for tweet level sentiment classification using recursive text preprocessing approach,” no. july, 2019, doi: 10.14569/ijacsa.2019.0100674. [26] m. b. alvi, n. a. mahoto, m. alvi, m. a. unar, and m. akram shaikh, “hybrid classification model for twitter data-a recursive preprocessing approach,” 5th int. multi-topic ict conf. technol. futur. gener. imtic 2018 proc., 2018, doi: 10.1109/imtic.2018.8467221. [27] c. g. harris, “detecting deceptive opinion spam using human computation,” aaai work. tech. rep., vol. ws-12-08, pp. 87–93, 2012. [28] p. cavallo et al., “journal of software,” vol. 9, no. 8, 2018. [29] m. ben-bassat, k. l. klove, and m. a. x. h. weil, “calo ( x = alo ( x ) e,” vol. 2, no. 3, pp. 261– 266, 1980. [30] a. akhter, m. b. alvi, and m. alvi, “forecasting multan estate prices using optimized regression techniques,” univ. sindh j. inf. commun. technol. , vol. 5, no. 4 se-computer science, apr. 2022, https://sujo.usindh.edu.pk/index.php/usjict/articl e/view/4340. [31] g. mujtaba and e. s. ryu, “client-driven personalized trailer framework using thumbnail containers,” ieee access, vol. 8, pp. 60417– 60427, 2020, doi: 10.1109/access.2020.2982992 template.doc vol. 3, no. 2 | july december 2020 sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 73 computation of electronic conductivity of pentance as semiconductor material using castep simulations nasif raza jaffri1, liu shi1, aftab ahmad rao2, usama abrar1, and jian yang1 abstract: density function theory (dft) interprets the stochastic behavior of electrons and hence predicts solid-state properties of materials. castep; a software to compute charge densities, spin densities, wavefunctions, relaxed atomic positions, forces, the fermi lev-el, the total energy, and symmetry operations. conventionally, inorganic materials like ge, si used to produce electronic devices. lately, organic electronics are introduced and is a growing branch of the electronics industry. although the rate of growth of this industry is high still, this industry is in its early stages. an organic field-effect transistor (ofet) is the major unit cells of this industry. to use organic materials as ofets; semiconductor material bandgap must be known. in this work; the castep software package was used to calculate pentacene (organic material) bandgap, bandgap types, and values. it came up with the results that pentacene is a material with direct bandgap and good electron conductivities. these instructions give basic guidelines for preparing camera-ready papers. keywords: organic electronics, ofet, castep, pentacene, dft. 1. introduction the term organic semiconductors refer to organic materials with characteristics similar to inorganic semiconductors (e.g. si, ge). like inorganic semiconductors, holes and electrons are responsible for the flow of current in organic semiconductors [1]. but the difference between these organic and inorganic semiconductors is that organic semiconductors have π conjugate bonds which allow electron movements through π electron cloud overlap. however, current flow through inorganic semiconductors is due to electron jumping between localized states and mobility gaps [2]. the history of solid-state electronic devices is not long. the first remarkable 1 school of control and computer engineering. north china electric power university beijing, 102206 china 2 department of electrical engineering, nfc-institute of engineering and fertilizer research faisalabad, pakistan. corresponding author: nasifraza@hotmail.com product produced in the electronics industry was a transistor in the year 1947. in a couple of decades, transistors were readily available at reasonable prices. transistors can be seen nearly in every type of electronic circuitry (e.g. from laptops to children’s toys). even nowadays many types of displays also use transistors (tfts, leds). these displays are replacing older technology (crt’s) quickly because they are cheap, cover less space and consume less power with good contrast ratio, brightness, and colours. in the last 50 years, silicon has been the major raw material in electronics manufacturing. electronic properties of organic solids were first noticed in the 1960s. at that time, only a basic understanding of the materials was known, by mainly focusing on one nasif raza jaffri (et al.) computation of electronic conductivity of pentance as semiconductor material using castep simulations (pp. 73 – 81) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 74 component of organic molecular crystals. however, it was soon concluded that like inorganic materials, roots of electrons and holes could be defined for organic materials as the charge carrier band is narrow in this case [3]. the story of organic materials started way back in 1862, when henry letheby of college london hospital observed conductivity in organic material, probably polyaniline [4]. in 1970 conductivity of organic polymers at low temperature was noted. alan j. heeger, alan g. macdiarmid, and hideki shirakawa are often credited for the "discovery and development" of conductive polymers and were jointly awarded the nobel prize in chemistry in 2000 for their 1977 report of similarly-oxidized and iodine-doped polyacetylene [5]. organic materials composed of primarily covalent bonds because of their structure, organic materials can either act as semiconductors or insulators [5]. organic electronics were first spotted for commercial interest when their photoconductive properties were observed. one of the problems with organic materials is their instability especially as they can degrade after exposure to air, water or light. so, there are a few limitations regarding the employment of organic structure and their manipulation. as electrons are primarily in covalent bonds, the electron mobility in organic materials is nowhere near their mobility in semiconductor materials [6]. organic devices efficiency depends upon the charge injection and chances of charge capture or from the balance of injection of electrons one side and holes from another side [7]. the device is in between two electrodes the negative is called lowest unoccupied molecular orbital (lumo) and positive as highest occupied molecular orbital (homo). 2. ofets organic field effect transistors (ofets) shows many advantages. their ability to deposit on the flexible substrate made it a popular product of organic electronics [8]. insulator, semiconductor, and electrodes are basic components of fet. in case of organic electronics, the semiconductor is composed of some organic material, while inorganic material can be used for others [1]. but some manufacturers prefer to make every part by using organic material. these devices are used on the flexible substrate for high switching applications [9] [10]. fig 1. layer by layer structure of ofet oligomers and polymers are two elementary segregations of organic semiconductors. oligomers are small molecules that are usually prepared using vacuum processes, and polymers with long chains are prepared using wet chemical techniques. despite, the process of preparation or type of material, the basic intension behind these materials is an efficient transfer charge carrier (electron or hole) [11]. the efficiency of materials is sometimes measured by the ease of charge injection in the material using electrodes. normally, the material is known as a good charge transporter when ionization energy is closer to the fermi level of electrodes [12]. in the absence of a voltage potential, the charge trans-fer is due to the diffusion which is defined by the equation. 〈𝑥 2〉 = 𝑛𝐷𝑡 (1) where 〈𝑥 2〉 is the displace d of charge is the diffusion coefficient, t is the time, n can be equal to 2,4 or 6 depending on 1nasif raza jaffri (et al.) computation of electronic conductivity of pentance as semiconductor material using castep simulations (pp. 73 – 81) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 75 dimensional, 2-dimensional or 3dimensional movement. the relation between the charge mobility μ and diffusion coefficient d is defined by the equation. 𝜇 = 𝑒𝐷 𝑘𝑏𝑇 (2) and e is electron charge; kb is boltzmann constant t for temperature. if the external electric field (f) applied will make the charge carrier drift, the movement of the charge carrier creates a velocity (v) in the semiconductor. charge mobility μ can also be defined with relation to field applied and velocity produced. 𝜇 = 𝑣 𝐹 (3) a. time of flight (tof) a charge carrier which is injected from one electrode with the help of applied potential, the time is taken by a carrier to reach another electrode is known as the time of flight (tof). the time of flight is used to measure the structural defects of materials. as known that 𝑣 = 𝑣𝑒𝑙𝑜𝑐𝑖𝑡𝑦 = 𝑑𝑖𝑠𝑝𝑙𝑎𝑐𝑒𝑚𝑒𝑛𝑡 𝑡𝑖𝑚𝑒 = 𝑑 𝑡 and 𝐹 = 𝐸𝑙𝑒𝑐𝑡𝑟𝑖𝑐 𝐹𝑖𝑒𝑙𝑑 = 𝐴𝑝𝑝𝑙𝑖𝑒𝑑 𝑉𝑜𝑙𝑡𝑎𝑔𝑒 𝐷𝑖𝑠𝑡𝑎𝑛𝑐𝑒 𝑏𝑒𝑡𝑤𝑒𝑒𝑛 𝑒𝑙𝑒𝑐𝑡𝑟𝑜𝑑𝑒𝑠 replacing these two values in equation (3) gives 𝜇 = 𝑑2 𝑣𝑡 (4) b. time of flight (tof) for ofets the behavior of the inorganic transistor in the linear and saturated region is approximately the same as it for organic materials [12]. this means the source to drain current equations for both regions of inorganic material fet is also applicable for ofet [11]. the equation for source unsaturated region is 𝐼𝑆𝐷 = 𝑊 𝐿 𝜇𝐶(𝑉𝐺 − 𝑉𝑇 )𝑉𝐷𝑆 (5) and the equation for the saturated region is 𝐼𝑆𝐷 = 𝑊 2𝐿 𝜇𝐶(𝑉𝐺 − 𝑉𝑇 ) 2 (6) 3. material under study benzene, c6h6, has six carbon atoms arranged in a ring. compounds which are formed with the combination of the benzene ring are called arenes or aromatics [13]. these compounds exhibit the properties of benzene on an extended scale. pentacene is composed of five benzene rings. in order to completely understand the properties of pentacene, the basic behavior of benzene must be known. fig 2. five benzene rings combine to form pentacene benzene with chemical formula c6h6 is a colorless and flammable liquid aromatic hydro-carbon possessing a distinct, characteristic odor with volatile nature. a major use of benzene is in the preparation of other organic compounds on an industrial scale. in the past, benzene was used in the shoe and garment industries as a sol-vent and for the preparation of some medicines [14]. in semiconductors, field mobility means charge/electron mobility, which means how easy electrons transport through materials pentacene has all of these properties and was selected for the development of ofets or oleds [8]. fig 3. benzene representation a. material properties pentacene; a dark blue powder shows sensitivity to light. the organic phototransistor (pts) shows high mobility of cm 0.42 v-1 s-1, a maximum photo responsivity of about 1000 a/w, and photocurrent/dark-current ratio in the region of 800 under white light irradiation nasif raza jaffri (et al.) computation of electronic conductivity of pentance as semiconductor material using castep simulations (pp. 73 – 81) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 76 of 30μw/cm2 [15]. the properties are comparable with those of pts based on amorphous silicon. meanwhile, it is interesting to see that the devices show a high air-stable property and high photosensitivity via the electric-field enhanced process [1]. all these phenomena were attributed to the intrinsic opticelectronic property of the organic semiconductor and optic-electric field effect. b. mobilities in material the mobility of holes in pentacene is higher as compared to other organic materials. it tends to form well-ordered molecular crystals. pentacene exhibit mobilities in excess of 1 cm2/vs. sio2. transistors can exhibit mobilities in excess of 1cm2/vs [14]. ofets which are made up of using single-crystal pentacene having up to 0.30 cm2/vs hole conductivity at room temperature, effective mobility, μeff vs and on/off ratios up to 5×106. the activation energy (ea) of a transistor can be reduced to 0.143 ev at room temperature by applying a negative gate voltage of about -50v. with ea = 0.143ev [12], the material reached a thermal equilibrium between trapped and free carriers, and it's found that free carriers are about 0.4% of total injected carries. in modern microelectronics, semiconductors are inject-ed with free carriers. this controlled injection is very helpful in controlling the mobility of the devices. organic semiconductors have the advantage of flexible processing of largearea devices at low cost. fets are used to investigate the physical properties of these materials. it's still the fact that accuracy achieved using inorganic materials is much better than the accuracy of organic materials. one of the major reasons for low accuracy is that intrinsic organic material has inter and intramolecular vibrational modes which scatter chare carrier and reduce mobility (μ). this drawback is not exhibited by inorganic materials which is the reason for their high mobility. polyacenes exhibit good properties for organic materials; among them, pentacene is one with the most promising features. among all polyacenes, pentacene has the smallest bandgap and has the highest effective mobility in polycrystalline organic thin-film fets, μeff = 0.3-1.5 cm2/vs. the value is comparable with amorphous si devices. another important notable feature is that, as the crystalline of the device increases, μeff also increases [11]. this fact reveals the need for a single crystal and requires the fabrication of single crystals for fets manufacture. a single crystal of pentacene fet was put under study, and it shows different results. the large negative vg of about 50v, ea (activation) energy to the value 0.143ev. the ea depends on ef and ev by ea ~ ef-ev on ef is the given fermi level of the material. ea on vg changes to the gradual shift of the hole fermi energy toward the valence band as more empty places become filled because of fet hole injection [1]. the number of injected carriers per unit area is given by 𝐶𝑆𝑉𝑔 = ∫ 𝑑𝐸𝑁𝑡 (𝐸) 𝐸𝐹0 𝐸𝐹1 (7) nt(e) is trapped carriers' energy distribution function of per unit area. while ef0 and ef1 are fermi energy levels without and with vg on, respectively. let's assume at any injection rate thermal equilibrium developed be-tween free and trap carriers [6]. the number of thermal-ly excited free carriers is given by 𝑃𝑓 = ∫ 𝑑𝐸𝑁𝑡 (𝐸)exp (𝐸𝑉 − 𝐸) 𝑘𝑏 𝑇⁄ 𝐸𝐶 𝐸𝐹1 (8) the conduction band energy ec upper limit of the integral can be replaced with ef0 in equation (8) as they are approximately the same at room temperature. the simplified expression will be 𝑃𝑓 = exp ((𝐸𝑉 − 𝐸) 𝑘𝑏 𝑇⁄ ) ∫ 𝑑𝐸𝑁𝑡 (𝐸) 𝐸𝐶 𝐸𝐹1 (9) the value of ∫ 𝑑𝐸𝑁𝑡 (𝐸) 𝐸𝐶 𝐸𝐹1 from equation (7) can be replaced in equation (9), the new equation will be 𝑃𝑓 = exp ((𝐸𝑉 − 𝐸) 𝑘𝑏 𝑇⁄ )𝐶𝑆 𝑉𝑔 (10) we can see that from the graph below that at 𝐸𝑉 − 𝐸𝐹1 is approximately equal to activation energy ea with negative sign nasif raza jaffri (et al.) computation of electronic conductivity of pentance as semiconductor material using castep simulations (pp. 73 – 81) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 77 0.143 ev. this gives that the free carriers are about 0.4% of the injected ones. 4. castep simulations castep is a software package that provides the decent atomic level description. this software is used for the prediction of material properties, e.g. energies (stress, forces), electronic structure, geometry optimization, molecular dynamic, magnetic responses, phonons, electric field responses, etc. the basic idea used in this software is the construction of hamiltonian, and after the construction of that hamiltonian, it calculates the full hamiltonian equation. to perform this task castep requires more than one input file, there are two input files in castep *. cell and *. param. these two files can be open simply by using windows notepad. the *.cell file contains the position of atoms in molecules hence contains the structure which has to be calculated, while *. param contains the information on how this calculation should be done. this code can be found in the appendix. the first line of code in parameter code is a comment; the software user can write anything here for himself to make a reference; it won't affect the output. as i tried to optimize the geometry of diamond, i wrote a comment diamond geometry optimization. the second line in the parameter file defines the task which has to be performed; in this case, it is geometry optimization; it can be phonons, band structure, nmr or single point energy. by default, it goes for single-point energy. the third line is for the exchange-correlation function as density functional theory uses local density approximation (lda) as its obvious choice for calculation; similarly, lda is default functional here. but other hybrid and new functions can also be used for calculation such as pw91, ldc-x, wc, b3lyp, etc. the next line in the parameter file is optimization speed, which directly relates to the ram of the system, the default value is 0, but it can be increased by changing it to +1,+2,… or decreased by -1,2,-3…. fix_occupancy is used to define the material as insulator or metal. the last line is the method defined for geometry optimization. it can be damped md (damped molecular dynamics) or delocalized but bfgs is the default. the appendix contains the code for cell file. the block-lattice consists of lattice parameters a, b, c and angles α,β,γ which defines how the lattice grows. then the position of atoms on x, y, z plane along with the k point. this input file is run by using plate form of msdos and can take from a few minutes to days for the completion depending upon the size of molecules, latticmeter, and method used for calculation after the simulation, the software creates an output file with the name of *.cst. this file contains the desired information. the first section consists of memory requirement for the job, next control parameters, variables used, system geometry, pseudopotentials, k-points, etc. the information produces in the output file was used for the calculations which are presented in the result section. 5. results and discussions castep calculates energies by growing periodically into three directions a, b and c. wavenumber k is de-fined as the number of wavelengths per unit distance. waves bombarded along each axis on the lattice and hence changes wavenumber (k) and changing the num-ber of wavelengths affects the factor k/a, k/b or k/c along with all three directions. this factor is varied from its maximum to minimum value (0-1) in many steps by software to calculate the energies of electrons involved. then these energies were drawn factor k/a, k/b and k/c again to find bandgap. as it is discussed in chapter 4 that there are many techniques to use density function-al theory; however, in these calculations, four of them (lda-x, pbe, pw91and wc) are used [16]. there are two types of bandgaps in semiconductors, direct bandgap, and indirect bandgap. if the conduction band minimum and valence band maximum occur at the same point in k-space, then the bandgap is known as a direct bandgap; otherwise, it is indirect [17]. the bandgap calculated is the difference between homo and lumo levels. nasif raza jaffri (et al.) computation of electronic conductivity of pentance as semiconductor material using castep simulations (pp. 73 – 81) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 78 table i: electron energies for lda-x, k/a, k/b and k/c table ii: rgies for lda-x, k/a, k/b and k/c table iii: electron energies for pwc91, k/a, k/b and k/c l a tt ic e p t. k/a 0 0.2 0.6 0.8 1 k/b 0 0.29 0.57 0.71 1 k/c 0 0.25 0.5 0.75 1 h o m o k/a -1.68 -1.65 -1.62 -1.65 -1.68 k/b -1.68 -1.69 -1.72 -1.69 -1.68 k/c -1.68 -1.68 -1.69 -1.68 -1.68 l u m o k/a -0.56 -0.57 -0.58 -0.57 -0.56 k/b -0.56 -0.53 -0.51 -0.53 -0.56 k/c -0.56 -0.57 -0.58 -0.57 -0.56 b a n d g a p k/c -1.12 -1.08 -1.04 -1.08 -1.12 k/b -1.12 -1.16 -1.21 -1.16 -1.12 k/c -1.12 -1.11 -1.11 -1.11 -1.12 l a tt ic e p t. k/a 0 0.27 0.55 0.73 1 k/b 0 0.22 0.56 0.78 1 k/c 0 0.2 0.6 0.8 1 h o m o k/a 0.76 0.78 0.71 0.78 0.76 k/b 0.757 0.678 0.484 0.678 0.757 k/c 0.757 0.752 0.743 0.752 0.757 l u m o k/a 1.57 1.57 1.65 1.57 1.57 k/b 1.568 1.625 1.772 1.625 1.568 k/c 1.568 1.564 1.557 1.564 1.568 b a n d g a p k/a -0.81 -0.79 -0.94 -0.79 -0.81 k/b -0.811 -0.947 -1.288 -0.947 -0.811 k/c -0.811 -0.812 -0.814 -0.812 -0.811 l a tt ic e p t. k/c 0 0.25 0.5 0.75 1 k/b 0 0.25 0.5 0.75 1 k/c 0 0.25 0.5 0.75 1 h o m o k/c -1.42 -1.43 -1.43 -1.43 -1.42 k/b -1.42 -1.44 -1.5 -1.44 -1.42 k/c -1.42 -1.43 -1.43 -1.43 -1.42 l u m o k/c -0.34 -0.35 -0.36 -0.35 -0.34 k/b -0.34 -0.31 -0.25 -0.31 -0.34 k/c -0.34 -0.35 -0.36 -0.35 -0.34 b a n d g a p k/c -1.08 -1.08 -1.07 -1.08 -1.08 k/b -1.08 -1.13 -1.25 -1.13 -1.08 k/c -1.08 -1.08 -1.07 -1.08 -1.08 nasif raza jaffri (et al.) computation of electronic conductivity of pentance as semiconductor material using castep simulations (pp. 73 – 81) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 79 a. lda-x results as the electron's spin, this density function defines the spin density of freedom; spin can be spin up or spin down. although local density function was derived, homogenous electron gas is sufficiently accurate for homogenous cases as well. the local density function is good with the error cancellation, and the spherical average is well approximated [16]. b. pbe results pbe is a short form of perdew-burkeernzerhof exchange and correlation functional. pbe is a simplification of pw91, which yields almost identical numerical results with simpler formulas from a simpler derivation [18]. calculation produced using pbe is shown below in table ii. c. pwc91 results pw is the perdew-wang correlation functional. the difference in calculation with pbe and pw91 is small. pw91 is more complex and involves more gradients in it, while pbe is a simplified version of pw91 [17]. 6. conclusions pentacene is a flexible material and has π conjugate [14]. the electronic conductivity in pentacene opens a new chapter for the semiconductor industry [6], as pentacene is a simple and basic organic polymer [7]. the results shown in the graphical form have a dot and continuous line in them. the continuous lines represent energies in valance and conduction band. results consistently show that when the conduction band goes in minima at the same point valance bond goes for its maxima. this showed that pentacene is a material with a direct bandgap. as described earlier in this chapter that direct bandgaps are good for the optical properties and materials with direct bandgaps produce bright visible lights. hence pentacene is the material that is a good candidate for material used for organic light-emitting diode. the other important thing to note is that the bandgap calculated by these methods is in the range of -0.8 to -1.2 ev [4]. this means that pentacene posses' good semiconductor and transistors made of this semiconductor will have good switching time. hence pentacene is not a bad choice for the manufacturing of organic fieldeffect transistors. appendix parameter and cell code *. param files normally contain following lines it in it comment: diamond geometry optimization task : geometryoptimization xc_functional : pw91 opt_strategy: speed basis_precision: precise fix_occupancy : true metals_method : dm geom_method: bfgs *.cell files have the following lines in it. %block lattice_abc 2.496238 2.496238 2.496238 60.0 60.0 60.0 %endblock lattice_abc %block positions_frac c 0.000 0.000 0.000 c 0.250 0.250 0.250 %endblock positions_frac kpoints_mp_grid 2 2 2 symmetry_generate %block species_pot cd:\castep\pseudopotentialsms\c _00.recpot %endblock species_pot nasif raza jaffri (et al.) computation of electronic conductivity of pentance as semiconductor material using castep simulations (pp. 73 – 81) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 80 fig 4. electron energies for lda-x: k/a, k/b and k/c fig 5. electron energies for pbe: k/a, k/b and k/c fig 6. electron energies for pw91: k/a, k/b and k/c conflict of interest the authors declare no conflict of interest. author contributions nasif raza jaffri and shi designed the developed the research idea. all the other others helped in in execution of simulations and collection of results. acknowledgment the authors wish to extend their gratitude to nsfc for sponsoring the research (no 61571189, 61871181) and to the state administration of foreign experts affairs for supporting the 111 projects (ref: b13009). references [1] c. lu et al., “progress in flexible organic thin-film transistors and integrated circuits,” sci. bull., vol. 61, no. 14, pp. 1081–1096, jul. 2016. [2] k. takagi, t. kuroda, m. sakaida, and h. masu, “molecular design for tuning electronic structure of π-conjugated polymers containing fused dithienobenzimidazole units,” polymer (guildf)., vol. 107, pp. 191–199, dec. 2016. [3] p. petelenz, z. g. soos, and e. umbach, “electronic processes in organic solids,” chem. phys., vol. 325, no. 1, pp. 1–2, jun. 2006. [4] n. t. kalyani, h. swart, and s. j. dhoble, “luminescence in organic semiconductors,” in principles and nasif raza jaffri (et al.) computation of electronic conductivity of pentance as semiconductor material using castep simulations (pp. 73 – 81) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 81 applications of organic light emitting diodes (oleds), elsevier, 2017, pp. 39–64. [5] y. shirota and h. kageyama, “organic materials for optoelectronic applications: overview,” in handbook of organic materials for electronic and photonic devices, elsevier, 2019, pp. 3–42. [6] d. schlettwein, “electronic properties of molecular organic semiconductor thin films,” in supramolecular photosensitive and electroactive materials, elsevier, 2001, pp. 211–338. [7] m. nitani, k. nakayama, k. maeda, m. omori, and m. uno, “organic temperature sensors based on conductive polymers patterned by a selective-wetting method,” org. electron., vol. 71, pp. 164–168, aug. 2019. [8] f. zhang, m. funahashi, and n. tamaoki, “flexible field-effect transistors from a liquid crystalline semiconductor by solution processes,” org. electron., vol. 11, no. 3, pp. 363– 368, mar. 2010. [9] g. casula et al., “a flexible organic memory device with a clearly disclosed resistive switching mechanism,” org. electron., vol. 64, pp. 209–215, jan. 2019. [10] g. fortunato, a. pecora, and l. maiolo, “polysilicon thin-film transistors on polymer substrates,” mater. sci. semicond. process., vol. 15, no. 6, pp. 627–641, dec. 2012. [11] k. ryu, i. kymissis, v. bulovic, and c. g. sodini, “direct extraction of mobility in pentacene ofets using cv and i-v measurements,” ieee electron device lett., vol. 26, no. 10, pp. 716–718, oct. 2005. [12] v. coropceanu, j. cornil, d. a. da silva filho, y. olivier, r. silbey, and j.-l. brédas, “charge transport in organic semiconductors,” chem. rev., vol. 107, no. 4, pp. 926–952, apr. 2007. [13] p. f. van hutten and g. k. sujan, “organic conductors and semiconductors, structure and morphology of,” in reference module in materials science and materials engineering, elsevier, 2016. [14] t. sekitani et al., “bending experiment on pentacene field-effect transistors on plastic films,” appl. phys. lett., vol. 86, no. 7, p. 073511, 2005. [15] f.-c. chen, “organic semiconductors,” in encyclopedia of modern optics, elsevier, 2018, pp. 220–231. [16] m. ribeiro, “electronic band gaps corrections using total energy with dft/lda-½ quasi-particle approximation,” comput. mater. sci., vol. 167, pp. 228–236, sep. 2019. [17] j. bergès, j. caillet, j. langlet, and j. kozelka, “hydration and `inverse hydration’ of platinum(ii) complexes: an analysis using the density functionals pw91 and blyp,” chem. phys. lett., vol. 344, no. 5–6, pp. 573– 577, aug. 2001. [18] i. a. pašti, a. jovanović, a. s. dobrota, s. v. mentus, b. johansson, and n. v. skorodumova, “atomic adsorption on pristine graphene along the periodic table of elements – from pbe to non-local functionals,” appl. surf. sci., vol. 436, pp. 433–440, apr. 2018. format template vol. 2, no. 2 | july december 2019 sjet | p-issn: 2616-7069 | e-issn: 2617-3115 | vol. 2 | no. 2 | © 2019 sukkur iba 21 cfd simulation of hawt blade and implementation of bem theory muhammad faizan younas1, awais ali1 and muhammad daud shafique1 1 dpeartment of mechanical engineering, comsats university islamabad, sahiwal campus, sahiwal, pakistan *corresponding author: faizanyounas356@gmail.com abstract: wind turbine blade design is of profound importance in the renewable energy industry. this paper reflects a simple yet effective methodology to simulate a horizontal axis wind turbine (hawt) blade. a blade of hawt was designed with the implementation of the blade element momentum theory (bem). with a tip speed ratio (tsr) of 8, a blade of radius 10 m was designed with naca 63-615 as a considered airfoil. in order to study the characteristics of flow over the designed blade, computational fluid dynamics (cfd) simulations using ansys fluent package were performed. using frame motion, an unstructured mesh of around 2 million, and y + = 1, contours of pressure, velocity, and flow around the immediate vicinity of the blade were shown. the value of torque was found to be 5.6 kn.m for the designed blade. lastly, a grid convergence study was done to find out the optimal size of mesh for this kind of simulation. results clearly showed the efficacy of fluent package to model simulations of this type. keywords: blade element momentum theory, computational fluid dynamics, tip speed ratio, ansys fluent package 1. introduction blade of a hawt is of great importance for wind turbines. they can have myriad configurations in length, type and number of airfoils. mostly blades are composed of a number of airfoils, instead of one, in order to ensure maximum lift at each section. bem theory is a frequently used approach for the design of a hawt blade. bem is used by nearly all wind industries for the blade design and its optimization. it is a highly derivative form of newton’s second law of motion[1], and currently the only commercially available source for blade design. bem theory considers a hawt blade to be composed of a number of elements. with an input value of tsr, free stream velocity, lift coefficient and design angle of attack (aoa), bem faizan younas (et al.), cfd simulation of hawt blade and implementation of bem theory (pp. 21 35) sukkur iba journal of emerging technologies sjet | volume 2 no. 2 july – december 2019 © sukkur iba university 22 provides important design parameters i.e. twist distribution, chord distribution, and a relative tip speed ratio of every blade element [2-6]. in addition to the design process, by utilizing an iterative process bem is also useful for the numerical computation of hawt performance [7, 8]. in today’s dynamic engineering environment, cfd is a burgeoning tool and has a broad spectrum of usage in myriad engineering fields. from modeling turbulence[9, 10], various chemical phenomena [11, 12], hvac systems [13, 14] and all the way to the food industry [15, 16] cfd has proven potential. the following are some of the studies related to current work. c. j. bai et.al. [17] designed a hawt with the application of bem theory. their study considered the national renewable energy research laboratory's (nrel) airfoil s822, a blade of radius 3m and an estimated output of 10kw. in addition, the improved bem theory which includes prandlt’s tip-loss correction factor and viterna-corrigan stall model was used for performance prediction. in order to bolster the result, ansys fluent package with k-ω sst turbulence model was used to verify the results obtained from bem. a good agreement was found between results from bem and that obtained from cfd simulations. in a study conducted by mehmet bakirci [18], two airfoils i.e. naca 64-421 and naca 65-415 were taken under consideration. in order to find the otsr (optimum tip speed ratio), six blade geometries were developed using of bem at tip-speed ratios of 6, 7, and 8. for the analysis part bem and cfd were deployed. a grid convergence study was also performed, with k-ω sst turbulence model the most accurate results were found at 2 million elements. the results shown a good agreement with bem analysis, it is worth mentioning that in every case the maximum power coefficient found at tsr greater than considered in design. in order to find the starting torque behavior, a small hawt was designed by umesh et.al.[19], bem was used for the design and analysis part. a computer program code with application of matlab was generated to predict performance. moreover, adams software was used in order to verify the results of bem computationally. with a blade radius of 5 m, consistent values of torque were obtained after 5 sec. in another study conducted by emrah kulunk et.al. [20], author designed a 100 kw hawt with the application of bem. the chosen airfoil was nrel s809, with 8.5 m blade and 9.43 m rotor radius. moreover, a matlab program was also developed to predict the performance parameters like power, thrust, torque and coefficient of performance at wind velocities ranging from 10 to 100 m/s. author also expounded on tip-loss correction factor for performance prediction. results shown a direct relation between the wind velocity and performance parameters, but up to a certain limit this relation is not much dominant, and increasing velocities does not tantamount to performance increase. a study was conducted to predict the performance of 150 kw hawt numerically and experimentally by yan-ting lin et.al. [21]. at different pitch angles the performance of hawt with 10.8 m blade radius was investigated. both bem and cfd were deployed, with k-ɛ turbulence model the best results were found at pitch angle 5°. moreover, results obtained from cfd and bem shown a good agreement. in a similar approach, effect of pitch angle on hawt performance was studied by sudhamshu et.al.[22]. at wind velocities of 7, 15.1, and 25.1 m/s ansys fluent package with sst k-ω turbulence model was used to find best pitch angle. results shown inverse relation of thrust coefficient with pitch angle. furthermore, for any given velocity optimum pitch angle was also studied. a number of cfd studies were performed in past to investigate wind turbine performance. lee et.al.[23] conducted study to investigate faizan younas (et al.), cfd simulation of hawt blade and implementation of bem theory (pp. 21 35) sukkur iba journal of emerging technologies sjet | volume 2 no. 2 july – december 2019 © sukkur iba university 23 the effect of blunt airfoil on hawt performance, with the application of ansys fluent, hawt blade were tested at different wind speeds. results proven the blunt airfoil to be auspicious. especially for small hawt; mainly because they operate on higher tsr. four methods for mesh independence study i.e. grid convergence study (gcs), general richardson extrapolation (gre), mesh refinement (mr) and fitting method (fm) was investigated by almohammadi et.al.[24] in case of a vertical axis wind turbine (vawt). results proven the fitting method to be best without any need for large mesh sizes. a study was conducted by moshfegi et.al. [25]. using sst k-ω turbulence model the effect of near wall grid spacing was studied. along the chord the separation point was found to be important factor after conducting 8 different cases, with element size no more than 5 million in every case. similar studies that chronicles around different cfd techniques to study wt performance were describe in[26-34] 2. methodoogy 2.1. bem for the implementation of bem. the total length of the blade was divided into “n” number of elements, bem treats every element as an independent member and provides design characteristics i.e. twist distribution and chord distribution that suits best at that member. in our case, the blade was divided into 10 elements with each of length 1 m. for the bem implementation, the input parameters are given in table-1. table i: design parameters following steps detail the procedure followed to calculate blade design parameters with bem theory: obtain local tip speed ratio for every element (1) where r is the local blade radius ranging from 1-10 calculate optimum relative wind angle for every element (2) calculation of twist distribution (3) calculation of chord distribution (4) where pcf is the prandlt’s tip loss correction factor given by (5) at every element of the blade calculations were performed using above steps. table-2 shows the output design parameters. fig. 1 shows the distribution of chord along the blade, as moving along the blade length, chord length decreases, same is the case with twist distribution and optimum relative wind angle shown in fig. 2 and fig. 3. in contrast, faizan younas (et al.), cfd simulation of hawt blade and implementation of bem theory (pp. 21 35) sukkur iba journal of emerging technologies sjet | volume 2 no. 2 july – december 2019 © sukkur iba university 24 local tsr increases along the blade length shown in fig. 4 table ii: calculated design parameters 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 c h o rd d is tr ib u ti o n ( m ) r/r fig. 1. variation of chord distribution with blade length 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 -5 0 5 10 15 20 25 30 t w is t d is tr ib u ti o n ( θ °) r/r fig. 2. variation of twist distribution with blade length 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 0 5 10 15 20 25 30 35 r e la ti v e w in d a n g le ( θ °) r/r fig. 3. variation of relative wind angle with blade length 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 0 1 2 3 4 5 6 7 8 9 l o c a l ti p s p e e d r a ti o r/r fig. 4. variation of local tip speed ratio with blade length the calculated design parameters were used to create a cad model in solidworks, the modeled blade is shown in fig. 5. it is worth mentioning that a hub radius of 0.5 m was assumed, but is not modeled in the present study as the only focus was to simulate the rotor. to bolster the fact that we did not model the hub is because of its aerodynamic shape, which does not hinder the performance of the turbine, hence its effect can be neglected. fig. 5. cad model of blade 2.2. cfd analysis of airfoil since airfoil cl is an input parameter so it is a good reason to perform 2d cfd analysis of the airfoil. 2d simulations were performed on an airfoil at 5° aoa, which is the maximum cl/cd angle for this airfoil. a cshape fluid domain was created with airfoil sitting in between the control volume fig. 6. faizan younas (et al.), cfd simulation of hawt blade and implementation of bem theory (pp. 21 35) sukkur iba journal of emerging technologies sjet | volume 2 no. 2 july – december 2019 © sukkur iba university 25 fig. 6. c-shape control volume the boundaries of the control volume were extended 15 m from the airfoil, and the length considered for airfoil was 1 m. a structured mesh was created in the fluid domain after importing geometry in ansys fluent. as shown in fig. 7, the mesh was refined at the vicinity of the airfoil using a biasing function. fig. 7. structured mesh around airfoil the size of the mesh in fig. 7 was around 100 k elements, as not much of variation in results was encountered upon increasing the size from 100 k. fig. 8 shows the structured mesh around the airfoil. fig.8. structured mesh around airfoil fig. 9 and fig. 10 shows the mesh around leading and trailing edge of the airfoil. fig. 9. mesh around leading edge fig. 10. mesh around trailing edge with an inlet velocity of 10 m/s, the residuals of 1e-6 were set for 2d simulations. because of the variation of the fluid velocity at the upper and lower side of the airfoil, a pressure difference was developed, and responsible for the lift creation. fig. 11 shows the pressure and velocity contours around the airfoil. (a) faizan younas (et al.), cfd simulation of hawt blade and implementation of bem theory (pp. 21 35) sukkur iba journal of emerging technologies sjet | volume 2 no. 2 july – december 2019 © sukkur iba university 26 (b) fig. 11. (a) pressure contours around airfoil (b) velocity contours around airfoil 2.3. cfd analysis of hawt to simulate the rotor a pie-shape domain was created. with the simulation of a single blade, and implementing a symmetry boundary condition, complete rotor was analyzed. this little trick thus saved us time and computational resources. fig. 12 shows a schematic of our designed control volume. blade was placed at the center of the domain extended to 3r of the blade from inlet and outlet section. similarly, the inlet radius of fluid domain was 2r and 4r for the outlet. fig. 13 and fig. 14 shows the actual mesh of control volume. fig. 12. schematic of control volume fig. 13 mesh of control volume fig. 14 mesh of control volume an unstructured mesh with around 2 million elements was generated. in order to better capture the near wall viscous effects and shear forces a dimensionless wall quantity y + is used. y + is distance of the first computing node from wall. y + value varies with different turbulence models, as for k ω-sst model it is generally, advice to keep y + < =1. k ω-sst is a twoequation eddy viscosity model and is highly effective in aerodynamics applications. it combines the benefits of both k-omega and kepsilon turbulence models, hence well suited for flows in sub viscous layers and regions away from the wall [35]. moreover, 27 layers of inflation were also part of the mesh, in order to better capture the viscous effects and shear forces near the wall. it may appear as a structured mesh around the airfoil, but these were the inflation layers faizan younas (et al.), cfd simulation of hawt blade and implementation of bem theory (pp. 21 35) sukkur iba journal of emerging technologies sjet | volume 2 no. 2 july – december 2019 © sukkur iba university 27 that wrap around the body to capture near wall effects. the mesh for this simulation contains tetrahedral elements only. a cut plane section of blade mesh is shown in fig. 15. and airfoil mesh is shown in fig. 16. fig. 15. mesh around blade fig. 16. mesh around airfoil table-3 shows the boundary conditions considered for simulations. as for the governing equations, reynoldsaveraged naiver-stokes (rans) equation was used to simulate the mean fluid flow given by where p stands for pressure, the term are viscous stresses, is the averaged velocity, is density, and are the reynold stresses. for modeling turbulence, turbulence model komega sst was used. the two-equation model is given by table iii: boundary conditions furthermore, continuity equation is given by (7) (8) (6) faizan younas (et al.), cfd simulation of hawt blade and implementation of bem theory (pp. 21 35) sukkur iba journal of emerging technologies sjet | volume 2 no. 2 july – december 2019 © sukkur iba university 28 3. results and discussions fig. 17 shows the complete fluid domain. for our simulations, residuals were set to 1e6, and the relaxation factors were set to default. fig. 18 shows the residuals monitor for our simulation. 1500 iterations were done so ensure the maximum convergence, but it can be seen from residual plots that all the factors approached maximum convergence within 300 iterations, and solution didn’t converge much afterwards. the tangential velocity was calculated by , as is selected, the tangential velocity should be 23 m/s at the blade tip. fig. 19 shows the velocity vectors on the simulated rotor, with a maximum velocity of 23 m/s at the tip. this is an important step in order to verify that our model worked well. fig. 17. complete fluid domain fig. 18. scaled residuals fig. 19. velocity vectors in stn frame fig. 20 show the distribution of pressure contours along the blade length, the difference of pressure between both sides of the blade yields axial forces that turns the turbine. this axial force is directly related to the developed pressure difference. fig. 20. pressure contours on rotor from fig. 21 fig. 30. pressure contours at each blade element of blade are shown. it can be well observed that as moving along the blade pressure difference increases and every element contributes more to the rotation of the blade. minimum pressure was found 18.21 pa at first element (r/r = 0.1) and a maximum of 351 pa at the last element (r/r = 1) shown in fig. 31. (9) faizan younas (et al.), cfd simulation of hawt blade and implementation of bem theory (pp. 21 35) sukkur iba journal of emerging technologies sjet | volume 2 no. 2 july – december 2019 © sukkur iba university 29 fig. 21. pressure contour at r/r = 0.1 fig. 22. pressure contour at r/r = 0.2 fig. 23. pressure contour at r/r = 0.3 fig. 24. pressure contour at r/r = 0.4 fig. 25. pressure contour at r/r = 0.5 fig. 26. pressure contour at r/r = 0.6 faizan younas (et al.), cfd simulation of hawt blade and implementation of bem theory (pp. 21 35) sukkur iba journal of emerging technologies sjet | volume 2 no. 2 july – december 2019 © sukkur iba university 30 fig. 27. pressure contour at r/r = 0.7 fig. 28. pressure contour at r/r = 0.8 fig. 29. pressure contour at r/r = 0.9 fig. 30. pressure contour at r/r = 1.0 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 0 50 100 150 200 250 300 350 400 m a x im u m p re s s u re ( p a ) r/r fig. 31. pressure distribution along blade similarly, from fig. 32 – fig. 41 velocity contours at each section of blade are shown. like pressure, velocity contours become more aggressive as moving along the blade, with a minimum velocity of 15 m/s at first element and maximum of 31 m/s at tip section. this rising trend is because of the decreasing angle of attack and chord distribution along the blade length. faizan younas (et al.), cfd simulation of hawt blade and implementation of bem theory (pp. 21 35) sukkur iba journal of emerging technologies sjet | volume 2 no. 2 july – december 2019 © sukkur iba university 31 fig. 32. velocity contour at r/r = 0.1 fig. 33. velocity contour at r/r = 0.2 fig. 34. velocity contour at r/r = 0.3 fig. 35. velocity contour at r/r = 0.4 fig. 36. velocity contour at r/r = 0.5 fig. 37. velocity contour at r/r = 0.6 faizan younas (et al.), cfd simulation of hawt blade and implementation of bem theory (pp. 21 35) sukkur iba journal of emerging technologies sjet | volume 2 no. 2 july – december 2019 © sukkur iba university 32 fig. 38. velocity contour at r/r = 0.7 fig. 39. velocity contour at r/r = 0.8 fig. 40. velocity contour at r/r = 0.9 fig. 41. velocity contour at r/r = 1.0 velocity contour at tip section (r/r = 1) shows the tip losses occurring at the blade. the torque value was also an important factor, at about 2 million mesh size the torque obtained was 5.6 kn.m. a grid convergence study was done using the mr technique to find the optimum size of mesh for this simulation setup. the variation of torque with mesh size is shown in fig. 42. as not a clear nuance was found in torque value on increasing mesh from 2 million cells. 2.0 2.5 3.0 3.5 4.0 5.3 5.4 5.5 5.6 5.7 5.8 5.9 t o rq u e ( k n .m ) mesh size (million cells) fig. 42. torque variation with mesh size due to the rotation of wind turbines, a disturbance in medium developed at the exit of the rotor known as wake effect. during the installation of wind farms, this phenomenon should take into consideration, so that the wake of one turbine does not hinder other’s performance. faizan younas (et al.), cfd simulation of hawt blade and implementation of bem theory (pp. 21 35) sukkur iba journal of emerging technologies sjet | volume 2 no. 2 july – december 2019 © sukkur iba university 33 fig. 43 shows the effect of the wake behind the moving turbine; the wake is maximum at the immediate exit from the turbine and a decline is observe as moving away from the rotor. 1m 2m fig. 43. wake behind turbine at 1m and 2m 3. conclusion and future work a simple yet effective methodology was proposed to simulate the hawt blade. moreover, a mesh refinement study using the mr technique was done to bolster the results. as for future work, this methodology can be implemented on blades with somewhat complex geometries, and a comparison can be done to investigate how far the unstructured mesh holds to provide accurate results. furthermore, a juxtaposition of results can be done using different techniques of mesh independence study. nomenclature cl lift coefficient aoa angle of attack cfd computational fluid dynamics fm fitting method wt wind turbine gre general richardson extrapolation mr mesh refinement gcs grid convergence study vawt vertical axis wind turbine r blade radius rans reynolds-averaged naiver-stokes nb number of blades vi inlet velocity αd design angle of attack λ tip speed ratio local tip speed ratio optimum wind angle local optimum wind angle twist distribution chord distribution prandlt’s correction factor rotational velocity hawt horizontal axis wind turbine bem blade element momentum theory 2d two dimension 3d three dimension tsr tip-speed ratio otsr optimum tip-speed ratio references [1] m. o. hansen, aerodynamics of wind turbines: routledge, 2015. [2] f. bohorquez, d. pines, and p. d. samuel, "small rotor design optimization using blade element momentum theory and hover tests," journal of aircraft, vol. 47, pp. 268-283, 2010. [3] e. kulunk and n. yilmaz, "hawt rotor design and performance analysis," in asme 2009 3rd international conference on energy sustainability collocated with the heat faizan younas (et al.), cfd simulation of hawt blade and implementation of bem theory (pp. 21 35) sukkur iba journal of emerging technologies sjet | volume 2 no. 2 july – december 2019 © sukkur iba university 34 transfer and interpack09 conferences, 2009, pp. 1019-1029. [4] e. kulunk and n. yilmaz, "aerodynamic design and performance analysis of hawt blades," in asme 2009 fluids engineering division summer meeting, 2009, pp. 12111222. [5] r. lanzafame, s. mauro, and m. messina, "hawt design and performance evaluation: improving the bem theory mathematical models," energy procedia, vol. 82, pp. 172179, 2015. [6] h. a. madsen, c. bak, m. døssing, r. mikkelsen, and s. øye, "validation and modification of the blade element momentum theory based on comparisons with actuator disc simulations," wind energy: an international journal for progress and applications in wind power conversion technology, vol. 13, pp. 373-389, 2010. [7] w. duan and f. zhao, "loading analysis and strength calculation of wind turbine blade based on blade element momentum theory and finite element method," in 2010 asiapacific power and energy engineering conference, 2010, pp. 1-4. [8] g. ingram, "wind turbine blade analysis using the blade element momentum method. version 1.1," school of engineering, durham university, uk, 2005. [9] j. aubin, d. f. fletcher, and c. xuereb, "modeling turbulent flow in stirred tanks with cfd: the influence of the modeling approach, turbulence model and numerical scheme," experimental thermal and fluid science, vol. 28, pp. 431-445, 2004. [10] z. j. zhai, z. zhang, w. zhang, and q. y. chen, "evaluation of various turbulence models in predicting airflow and turbulence in enclosed environments by cfd: part 1— summary of prevalent turbulence models," hvac&r research, vol. 13, pp. 853-870, 2007. [11] c. yin, l. a. rosendahl, and s. k. kær, "chemistry and radiation in oxy-fuel combustion: a computational fluid dynamics modeling study," fuel, vol. 90, pp. 25192529, 2011. [12] m. n. kashid, d. w. agar, and s. turek, "cfd modelling of mass transfer with and without chemical reaction in the liquid–liquid slug flow microreactor," chemical engineering science, vol. 62, pp. 5102-5109, 2007. [13] j. floyd, "coupling a network hvac model to a computational fluid dynamics model using large eddy simulation," fire safety science, vol. 10, pp. 459-470, 2011. [14] a. patidar, s. natarajan, and m. pande, "cfd analysis and validation of an automotive hvac system," sae technical paper 01487191, 2009. [15] t. norton and d.-w. sun, "computational fluid dynamics (cfd)–an effective and efficient design and analysis tool for the food industry: a review," trends in food science & technology, vol. 17, pp. 600-620, 2006. [16] v. chanteloup and p.-s. mirade, "computational fluid dynamics (cfd) modelling of local mean age of air distribution in forced-ventilation food plants," journal of food engineering, vol. 90, pp. 90-103, 2009. [17] c. bai, f. hsiao, m. li, g. huang, and y. chen, "design of 10 kw horizontal-axis wind turbine (hawt) blade and aerodynamic investigation using numerical simulation," procedia engineering, vol. 67, pp. 279-287, 2013. [18] m. bakırcı and s. yılmaz, "theoretical and computational investigations of the optimal tip-speed ratio of horizontal-axis wind turbines," engineering science and technology, an international journal, vol. 21, pp. 1128-1142, 2018. [19] u. chaudhary, p. mondal, p. tripathy, s. k. nayak, and u. k. saha, "modeling and optimal design of small hawt blades for analyzing the starting torque behavior," in 2014 eighteenth national power systems conference (npsc), 2014, pp. 1-6. [20] e. kulunk and n. yilmaz, "hawt rotor design and performance analysis," pp. 10191029, 2009. [21] y.-t. lin, p.-h. chiu, and c.-c. huang, "an experimental and numerical investigation on the power performance of 150 kw horizontal axis wind turbine," renewable energy, vol. 113, pp. 85-93, 2017/12/01/ 2017. [22] s. a.r, m. c. pandey, n. sunil, s. n.s, v. mugundhan, and r. k. velamati, "numerical study of effect of pitch angle on performance characteristics of a hawt," engineering science and technology, an international journal, vol. 19, pp. 632-641, 2016/03/01/ 2016. [23] s. g. lee, s. j. park, k. s. lee, and c. chung, "performance prediction of nrel (national renewable energy laboratory) phase vi blade adopting blunt trailing edge airfoil," energy, vol. 47, pp. 47-61, 2012/11/01/ 2012. [24] k. m. almohammadi, d. b. ingham, l. ma, and m. pourkashan, "computational fluid dynamics (cfd) mesh independency techniques for a straight blade vertical axis faizan younas (et al.), cfd simulation of hawt blade and implementation of bem theory (pp. 21 35) sukkur iba journal of emerging technologies sjet | volume 2 no. 2 july – december 2019 © sukkur iba university 35 wind turbine," energy, vol. 58, pp. 483-493, 2013/09/01/ 2013. [25] m. moshfeghi, y. j. song, and y. h. xie, "effects of near-wall grid spacing on sst-kω model using nrel phase vi horizontal axis wind turbine," journal of wind engineering and industrial aerodynamics, vol. 107-108, pp. 94-105, 2012/08/01/ 2012. [26] j. m. o'brien, t. m. young, j. m. early, and p. c. griffin, "an assessment of commercial cfd turbulence models for near wake hawt modelling," journal of wind engineering and industrial aerodynamics, vol. 176, pp. 32-53, 2018/05/01/ 2018. [27] c.-j. bai and w.-c. wang, "review of computational and experimental approaches to analysis of aerodynamic performance in horizontal-axis wind turbines (hawts)," renewable and sustainable energy reviews, vol. 63, pp. 506-519, 2016/09/01/ 2016. [28] r. lanzafame, s. mauro, and m. messina, "evaluation of the radial flow effects on micro hawts through the use of a transition cfd 3d model – part i: state of the art and numerical model review," energy procedia, vol. 82, pp. 156-163, 2015/12/01/ 2015. [29] a. rezaeiha, h. montazeri, and b. blocken, "on the accuracy of turbulence models for cfd simulations of vertical axis wind turbines," energy, 2019/05/16/ 2019. [30] j. m. o'brien, t. m. young, d. c. o'mahoney, and p. c. griffin, "horizontal axis wind turbine research: a review of commercial cfd, fe codes and experimental practices," progress in aerospace sciences, vol. 92, pp. 1-24, 2017/07/01/ 2017. [31] w. miao, c. li, g. pavesi, j. yang, and x. xie, "investigation of wake characteristics of a yawed hawt and its impacts on the inline downstream wind turbine using unsteady cfd," journal of wind engineering and industrial aerodynamics, vol. 168, pp. 60-71, 2017/09/01/ 2017. [32] f. carneiro, l. moura, p. c. rocha, r. p. lima, and k. ismail, "application and analysis of the moving mesh algorithm ami in a small scale hawt: validation with field test's results against the frozen rotor approach," energy, vol. 171, pp. 819-829, 2019. [33] y.-j. chen, g.-y. huang, y.-c. shiah, and y.-l. tsai, "performance prediction for small horizontal axis wind turbine (hawt) by integrated theory and experimental verifications," international journal of precision engineering and manufacturing-green technology, pp. 1-10, 2019. [34] s. sakaria, m. tailor, and s. joshi, "modeling & simulation analysis of 800 kw hawt," in ictea: international conference on thermal engineering, 2019. [35] f. r. menter, m. kuntz, and r. langtry, "ten years of industrial experience with the sst turbulence model," turbulence, heat and mass transfer, vol. 4, pp. 625-632, 2003. format template vol. 3, no. 2 | july december 2020 sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 1 experimental analysis of lead acid battery by introducing graphene & lead composite muhammad atif qaimkhani1 , saifullah samo1, shakeel ahmed shaikh1, tanweer hussain1 abstract: in this paper, an experimental analysis of grid material for a lead acid battery is presented, where graphene is introduced in lead by using powder metallurgy technique. in proposed composite, the graphene is added to grid material of lead acid battery to increase battery life cycle, performance, charge acceptance rate. four lead-graphene composite specimen of different composition are developed, for performing the series of tests to analyze charge acceptance rate. of lead acid battery. the graphene and lead are used with different percentage ratios, a good percentage of the graphene is found between the 0.5% to 2.0%. experimental result shows the effectiveness of composites prepared. the results obtained also compare with the spongy lead which is being normally used in lead acid batteries. keywords: energy storage devices, energy storage materials, graphene, lead acid battery 1. introduction potential use of graphene is the thinnest material and has a potential use in different daily life applications is in increasing. it is a hexagonal two-dimensional lattice, made of a single layer of bonded carbon atoms. defect free, single crystalline graphene possess the highest strength and exhibits unique mechanical, electrical and thermal properties [1-5]. the lead is a heavy metal with greater density as compared to graphene. graphene is a best candidate for electrode material to store the energy. as, there are different sources to generate electric energy. the search is still going on to replace the non-renewable sources with renewable sources to generate the electric energy. wind turbines and solar panels are good example of renewable sources, but these 1mehran university of engineering & technology, jamshoro, 76090, sindh, pakistan corresponding author: tanweer.hussain@faculty.muet.edu.pk sources are not available 24/7 and vary from seconds to hours and days [6]. therefore, storing of electrical energy is required to overcome the intermittency. it is important that the battery should be reliable and capable of delivering required power and energy when required. battery is a series of cells and can be used to store electrical energy. different combinations of materials can be used to manufacture cells, examples are sodiumsulphur (nas), nickel-cadmium (nicd), lithium polymer (li-ion polymer), lead-acid (pb), and lithium-ion (li-ion) [7-9]. there are different selection criteria for battery, like life cycle, depth of discharge robustness, power density, cost, temperature, and so on [10-11]. besides traditional use of lead acid batteries in electric vehicles, load leveling, and solar energy storage has been observed, this new trend demands certain challenges in the design muhammad atif qaimkhani (et al.), experimental analysis of lead acid battery by introducing graphene & lead composite (pp. 1 12) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 2 too. charge acceptance rate is one of those challenges. the main problems with the rechargeable batteries are sulfation of electrolyte, stratification of electrolyte, electrode corrosion and non-cohesion of dynamic mass. these failures lead to decrease in life cycle, performance, charge acceptance rate etc. of rechargeable batteries. this research focused to increase charge acceptance rate of the grid material that indirectly leads to increase life cycle and performance of lead acid batteries, by using graphene. phosphoric corrosive, the most every now and again considered electrolytic added substance, with positive and negative consequences for battery performance [12]. h3po4 was found to decrease sulfation, particularly after profound release [13], increment the battery cycle life [14] and back off self-release [15]. the genuine disservice of expansion of h3po4 was observed to be a misfortune in cell limit [16]. the impact of h3po4 on the effectiveness of arrangement of pbo2 on positiveframework amid charging was noticed to rely upon the charging constraints. citrus extract as an electrolytic added substance was accounted for to diminish oneself release of lead-corrosive batteries by the concealment of pbo2 reduction [17]. whenever, the amount of electrolyte and water increases more than maximum rate, chemical reaction takes place and reacts with lead and other metals in the battery. which can cause sulfation and damage internal parts of battery, because of corrosion charge rate decrease and battery can discharge at very short amount of time. sulfate affects the charging cycle, results longer charging times and incomplete charging with higher battery temperature [18,19]. the low energy density and slow charging are major drawback of lead acid batteries [20]. the configuration of battery grid can also improve the efficiency [21]. the aim of research is to increase the charge acceptance rate, enhance life cycle & improve efficiency of lead acid battery by using a such enormous material that is graphene. present experimental analysis is focused on contribution in greening the environment. some percentile of graphene is introduced in lead by powder metallurgy techniques, which is used as grid material. graphene is an allotropic form of carbon and has properties of super conductor it does not participate in the reaction but only protect from the corrosion and reduce the resistance between the spongy lead and sulfuric acid. in this study two approaches are applied experimental approach as well as analytical approach to achieve improvement in the lead acid battery. 2. specimen preparation the powder-metallurgy process comprises of 4 essential steps: (1) powder fabrication (2) mixing (blending) (3) compaction (4) sintering. the first step of powder metallurgy is powder manufacturing as shown in fig. 1. it involves preparing, characterizing, and treating material powder which may have solid stimulus on the quality of the final finished product. the size of powder particles normally ranges from 1-100 μm, preferably 10-20 μm. fig. 2 shows the powder blending and compaction. mixing grants consistency in states of the powder particles and facilitates mixing of various powders particles to enhance physical properties. fig. 1. general procedure of powder metallurgy method. muhammad atif qaimkhani (et al.), experimental analysis of lead acid battery by introducing graphene & lead composite (pp. 1 12) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 3 (a) (b) fig. 2. (a) powder blending (b) powder compaction. lubricants can be added to amid mixing to enhance the stream and lessen the contact among powder and bites the dust. binders can be added to enhance the green quality of material amid compaction process. the compaction pressure ranges between 3 to 120 tons/in2. the compaction exercise reduces empty space, enhances density, and produce grip and bonding between powder particles to enhance strength. the sintering process is used to convert powder into finished parts, it compacted in a furnace to a temperature below the highest melting point from the constituents. in this study solid state sintering was used to increase the high strength for that the sintering temperature was set at 229c which is 69.92% of the melting point of lead and let them further covering all area of the sample for an hour in a controlled furnace and later on slow cooling of specimen done by natural air. after processing all basic steps of powder metallurgy, the final product is shown in fig. 3, needed no further machining. fig. 3. final product / finished specimen. specimens of same size and shape with varying compositions were developed as per data given in table-1. electrical properties and their difference have been noted of every sample by same procedure. these samples are varied in thickness and in percentage of materials used in composite. electrical resistivity and conductivity have been carried out. 3. experimental analysis: the four specimens of composites were developed with different composition of lead and graphene. electrical properties and their difference have been noted of each specimen. a series of tests are conducted to analyze the charge acceptance rate of lead acid battery. such tests include electrical resistivity, cyclic voltammetry, electrical conductivity, impedance spectra, cyclic voltammetry, energy dispersive x-ray spectrometer, scanning electron microscopy, microstructure, corrosion test & charge potential. table i. specimen characteristics sr.# composition (%) lengt h (m) width (m) area (m2) resistance (ω) electrical resistivity (ω*m) electric al conduc tance (s/m) 1 lead =99.5 graphene = 0.5 0.054 0.054 0.002916 1.7 0.0918 10.893 2 2 lead =99.0 graphene = 1.0 0.054 0.054 0.002916 1.5 0.081 12.346 3 lead =98.5 graphene = 1.5 0.054 0.054 0.002916 1.5 0.081 12.346 4 lead =98.0 graphene = 2.0 0.054 0.054 0.002916 1.7 0.0918 10.893 2 muhammad atif qaimkhani (et al.), experimental analysis of lead acid battery by introducing graphene & lead composite (pp. 1 12) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 4 3.1. microstructure test: microstructure test has been carried on metallurgical microscope at laboratory of metallurgy & materials engineering department laboratory, in which 2% etchant of natal added on the surface of each sample after grinding the samples at 2000 waterproof paper. this test shows proper mixing of both materials, surface of samples is tested and verified, which give us optimum results that these materials are added and bounded properly or not. (a) (b) (c) (d) fig. 4. (a) graphene is 0.5% and lead is 99.5%. (b) graphene is 1.0% and lead is 99%. (c) graphene is 1.5% and lead is 98.5%. (d) graphene is 2% and lead is 98%. fig.4 for each samples at 500 zoom extent shows the granular structure of both materials. in fig. 4 (a) the composition percentage of graphene is 0.5% whereas the percentage of lead is 99.5%. the magnification of this figure is 500x zoom and analyze material structure on the surface of the composite. dark grey color shows the presence of graphene whereas white color shows lead. from the fig. 4(a) it is noted that at some points graphene is not properly mixed and that made bulk of graphene is there instead of granular structure shown in dark gray color. at these points current density is high, but chances of disintegration are also high. in fig. 4(b) the composition percentage of graphene is 1.0% whereas the percentage of lead is 99.0%. the magnification of this figure is 500x. it is shown in the fig. 4(b) that mixing of both materials is not equal because most of the graphene is not mixed properly with lead. it is also noted that 99% of lead is mixed with minimum of amount of graphene. whereas the excess amount of graphene can dispute easily in open atmosphere. in fig. 4(c) the composition percentage of graphene is 1.5% whereas the percentage of lead is 98.5% and the magnification of this figure is 500x. the fig. 4(c) shows the proper mixing of both materials all over the surface. this proper mixing can withstand with high conductivity and no powder can dispatch or dilute with acid. in fig. 4(d) the composition percentage of graphene is 2.0% whereas the percentage of lead is 98%. the magnification of this figure is 500x. the fig. 4 (d) shows that excess amount of graphene is not mixed properly with lead. it concludes that this sample can easily break down if high flow of charge or applied voltage high. 3.2. charge potential test: charge potential test was carried out in the electrical of engineering department laboratory, by using dc power supply sps1820 in which material is placed between the electrodes and vary the voltage ranges from 0.7v to 2.2 v and observing that how much current can easily pass from these voltage ranges. observation table readings which collect from this test are given in table 2 and graphs in fig. 5 to fig. 8 are plotted based on these results. muhammad atif qaimkhani (et al.), experimental analysis of lead acid battery by introducing graphene & lead composite (pp. 1 12) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 5 in table 2 these current and voltage values shall measure from the d-c power supply to find out that how much lead acid battery will perform work on these electric potential ranges. by keeping the constant range of voltage for every sample, variation in current is noted. fig. 5. the composition of graphene material is 2.0% and lead is 98.0%. fig. 6. the composition of graphene material is 1.0% and lead is 99.0%. table ii. specimen characteristics specimen no:01 pb=99.5% c=0.5% specimen no:02 pb=99% c=1.0% specimen no:03 pb=98.5% c=1.5% specimen no:04 pb=98.0% c=2.0% voltage (v) volt current (i)amp: voltage (v) volt current (i)amp: voltage (v)volt current (i)amp: voltage (v)volt current (i)amp: 0.82 7 0.70 4.2 0.73 10 0.82 4.9 1.0 9 0.96 6 0.82 12.9 1.0 6.2 1.23 12.0 1.0 6 1.05 16 1.25 12.6 1.41 15.0 1.20 8 1.20 17.7 1.47 17.0 1.60 15.7 1.46 10 1.42 17.8 1.63 17.2 1.80 18.0 1.66 11.8 1.62 18.1 1.82 17.7 2.0 19 1.82 16 1.84 18.3 2.05 20.0 muhammad atif qaimkhani (et al.), experimental analysis of lead acid battery by introducing graphene & lead composite (pp. 1 12) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 6 theses graph shows how much a current is gained at a specific range of voltage. fig. 5, is analyzed that the current conduction of this specimen-01 is low as compare to other specimens which shows that graphene and lead are not mixed properly because at same applied voltage current varies and comparatively to other specimens, its charge rate is slow that it requires more voltage for same conduction of current. fig. 7. the composition of graphene material is 1.5% and lead is 98.50%. fig. 8. the composition of graphene material is 0.5% and lead is 99.5%. muhammad atif qaimkhani (et al.), experimental analysis of lead acid battery by introducing graphene & lead composite (pp. 1 12) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 7 in fig. 6, the composition of graphene material is 1.0% and lead is 99.0%. it is analyzed that applied voltages current conduction is less than specimen-01. in fig. 7, the composition of graphene material is 1.5% and lead is 98.5%. the specimen-03 can conduct maximum amount of current at peak amount of voltage and remains constant at that range of voltage, which shows that graphene and lead can withstand high current density. in fig. 8, the composition of graphene material is 2.0% and lead is 98.0%. it is analyzed that the current conduction of specimen-04 is low as compare to other specimens, which shows that graphene and lead are not mixed properly because at same applied voltage current varies and comparatively to other specimens, its charge rate is slow that it requires more voltage for same conduction of current. 3.3. scanning electron microscopy test the technique was instated with the smooth cutting of center chips and their mounting test stub, utilizing a conductive twofold sided-carbon arrangement tape. the primary and secondary that is anodic and cathodic motion of electrons forms bright images of specimen. scanning electron microscopy test of every specimen is carried out at 100 zoom extent and applied 20kv. in fig. 9(a), the specimen no. 1 shows that primary electrons which only passes from lead and very little from graphene whereas secondary electrons are scattered around the surface. the grey color shows the concentration of lead and graphene whereas black shows the void or unmixed material. (a) (b) (c) (d) fig. 9. microstructure test of specimens at 500x magnification. those electrons which pass from the specimen shows the materials are properly mixed and conduction of charges will be continuous at these points. fig. 9(a) is electronic image and shows that the material in specimen no. 1 is making bulk instead of making granular structure at the center of sample which leads to the breakage of specimen by applying continues amount of force or by sudden high voltage. in fig. 9(b), the specimen no. 2 shows that most of the material is properly mixed and primary electrons passed through it whereas at the upper side of sample voids are appeared, which shows that electrons cannot pass through this area. this sample can easily diffuse when it reacts with acids. in fig. 9(c), the specimen no. 3, it is noted that both materials are mixed properly, and no voids are appeared. this shows all the electrons are passed from the specimen and the whole sample can conduct current at every point of it. in fig. 9(d), specimen no. 4 shows that the upper corners of this sample are not mixed properly, and electrons scattered back and there are some other voids in center of sample. fig. 9(d) shows that flow of charges at any point will not be continued. 3.4. energy dispersive x-ray spectrometer test energy dispersive x-ray spectroscopy test is conducted to identify and quantify the elemental compositions in developed specimens. from fig. 10, it is noted that less amount of graphene is mixed and 0.5% of graphene is used specimen no. 01. because of minimum amount of graphene additives are less. only oxygen is present in this specimen. muhammad atif qaimkhani (et al.), experimental analysis of lead acid battery by introducing graphene & lead composite (pp. 1 12) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 8 fig. 10. energy dispersive x-ray spectrometer test of specimen no. 01. fig. 11. energy dispersive x-ray spectrometer test of specimen no. 02. fig. 12. energy dispersive x-ray spectrometer test of specimen no. 03. fig. 13. energy dispersive x-ray spectrometer test of specimen no. 04. fig. 11, for specimen no. 02, where 1% of graphene is used. it is analyzed that different materials are found such as aluminum, iron etc. these additive materials can damage the composition and can react with acid. fig. 12 is for specimen no. 03, where 1.5% of graphene is used and from the graph, equal amount of other crystalline materials is found. these additives are not reacting with lead but can easily react with acid and can generate the gaseous issues. from fig. 13 is clearly shown that graphene is not mixed properly with lead and because of excess amount of graphene additives are present at high rate. it can damage sample easily and cannot be used for more cycles. from all these figures, it can be identified that in these material lead and graphene have some unknown crystalline additives are added which are present in every sample. these materials include carbon, iron, calcium, aluminum etc. they may be because of testing equipment or might be because of carbon in graphene. but all these additive materials are at very short amount in each sample which may not damage the sample mixture. 3.5. corrosion test this test for the internal protection of the battery. in these test tafel plots are generated between the log current and potential which shows the how much log current resist at the different voltage. this is done by putting a sample in 25% of dilute sulfuric acid with three electrodes terminal then dip in the container muhammad atif qaimkhani (et al.), experimental analysis of lead acid battery by introducing graphene & lead composite (pp. 1 12) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 9 and run the program on computer then plots are generated automatically. fig. 14. corrosion test result of specimen no. 01. fig. 15. corrosion test result of specimen no. 02. fig. 16. corrosion test result of specimen no. 03. fig. 17. corrosion test result of specimen no. 04. fig. 14 for specimen no. 01 shows that with the less amount of voltage and current, corrosion increases. here graphene is diluting in acid rapidly it is not mixed properly. fig. 15 for specimen no. 02 shows that decrease in voltage and current are not affecting on corrosion, it remains constant. that means by this concentration of specimen no. 02 constant dilution of materials in acid occurs. fig. 16 for specimen no. 03 shows that at very amount of current and voltage, minimum corrosion occurs, which means that both materials are mixed properly, and less amount of material can be transmitted in acid and less corrosion occurs. fig. 17 for specimen no. 03 shows that high amount of corrosion occurs at constant rate, at each cycle material will be transmitted in acid at large quantity. 3.6. impedance spectra test this test is based on computer software and plots are generated between the log ohm and potential. this is done by putting specimens in 25% of dilute sulfuric acid with three electrodes terminal then dip in the container and run the program to generate the plots. if the value of impedance is a smaller amount, then it will accommodate fast charge and charge capacity will have increased. fig. 18 for specimen no. 1 shows that at the range of 0.8v to 2.2v maximum current that is 3.3 z/ohm have achieved but that will not be efficient because at very minimum voltage range such quantity of current can generate heat. fig. 19 for specimen no. 2 shows that at voltage ranges 0.8v to 2.2v less amount of muhammad atif qaimkhani (et al.), experimental analysis of lead acid battery by introducing graphene & lead composite (pp. 1 12) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 10 current is conducted, which means materials are not properly mixed. because of low conductivity of charges, it causes great amount of corrosion. fig. 20 for specimen no. 3 shows that it is analyzed that at range of 0.8v to 2.2v peak amount of current is conducted. the specimen no. 3 is efficient to use because there will be less chances of corrosion. fig. 21 for specimen no. 4 shows that it can conduct good rate of charge but because of fluctuations it can break easily at very low voltage range. fig. 18. impedance spectra test result of specimen no. 01. fig. 19. impedance spectra test result of specimen no. 02. fig. 20. impedance spectra test result of specimen no. 03. fig. 21. impedance spectra test result of specimen no. 04. 3.7. x-ray diffraction test x-beam powder diffraction is a fastexpository method mainly developed for stage distinguishing proof of a crystalline-material and can give data at unit-cell measurements. fig. 22 shows bulk analytical composition of all specimens. the maximum peak of lead is lying in between the 30-40 degree of all specimens. although we can define the material which is present in all specimens based on energy dispersive x-ray spectrometer. fig. 22. xrd test results of all specimens. 3.8. cyclic voltammetry (cv) test this technique is used to measure the current that develops in an electrochemical cell under conditions where voltage is more than that predicted by the nernst equation. cyclic voltammetry test is performed by cycling the potential of a working electrode, and measuring the resulting current is performed by cycling the capability of a working cathode and estimating the subsequent current. fig. 23 shows that at 10 repeating cycle, voltage ranges from 0.6v to 2.2v and current 9.80a. it shows that every cycle there is chances of breakage of material or dispatching can occur at very low quantity. fig. 24 shows that that at muhammad atif qaimkhani (et al.), experimental analysis of lead acid battery by introducing graphene & lead composite (pp. 1 12) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 11 10 cycles there is no any point of breakage and constant amount of reduction from material occur at same voltage range and current. fig. 25 shows that at same voltage range and current constant amount of reduction occurs that is with increase in current at maximum level constant dissipating occurs. it will decrease the life span of specimen. fig. 26 shows that at same voltage range it conducts very low current and constant reduction of material in each cycle occurs. fig. 23. cv test result of specimen no. 01. fig. 24. cv test result of specimen no. 02. fig. 25. cv test result of specimen no. 03. fig. 26. cv test result of specimen no. 04. 4. conclusion the objective of this research was to increase the charge acceptance rate, enhance life cycle & improve efficiency of lead acid battery and achieved by using an enormous material graphene with lead material. by changing material composition (lead & graphene) and performing experiments, satisfactory results and improvement was observed in the charge acceptance rate of the lead acid battery grid material. the results obtained also compare with the spongy lead grid material, which is currently being used in lead acid battery. the experimental analysis concluded that graphene and lead composite can be used as grid material but there are some limitations. in this study graphene was used from 0.5% to 2.0%. a good percentage of the graphene may be used between the 0.5% to 2.0%. in some range 0.5% of graphene in lead may not be acceptable because of the cyclic voltammetry (cv) performance. cv performance of 0.5% graphene in lead increases the oxidation current which means that will leads to instability, whereas 2.0% graphene in lead, corrosion rate is too fast. finally, it was concluded from all specimens that sample no. 3 in which 1.5% of graphene was used with lead, is more efficient and can be used for grid. muhammad atif qaimkhani (et al.), experimental analysis of lead acid battery by introducing graphene & lead composite (pp. 1 12) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 12 references [1] xin, g., et al., large‐area freestanding graphene paper for superior thermal management. advanced materials, 2014. 26(26): p. 4521-4526. [2] xiang, j. and l.t. drzal, electron and phonon transport in au nanoparticle decorated graphene nanoplatelet nanostructured paper. acs applied materials & interfaces, 2011. 3(4): p. 1325-1332. [3] dong, c., comment on" advanced mechanical properties of graphene paper". journal of applied physics, 2012. 111: p. 106101-106101. [4] huang, x., x.y. qi, and f. boey, zhang. h. graphene-based composites. chem. soc. rev, 2012. 41: p. 666-686. [5] huang, w., x. ouyang, and l.j. lee, acs nano 6, 10178 (2012). crossref, isi. [6] bollen, m.h.j. and f. hassan, integration of distributed generation in the power system. vol. 80. 2011: john wiley & sons. [7] dell, r. and d.a.j. rand, understanding batteries. 2001: royal society of chemistry. [8] pavlov, d. and l.-a. batteries, science and technology: a handbook of lead-acid battery technology and its influence on the product. 2017, elsevier. [9] julien, c., et al., lithium batteries, in lithium batteries. 2016, springer. p. 29-68. [10] chen, a. and p.k. sen. advancement in battery technology: a state-of-the-art review. ieee. [11] alamgir, m., lithium has transformed vehicle technology: how trends in li-ion battery technology have developed for vehicle electrification. ieee electrification magazine, 2017. 5(1): p. 43-52. [12] abd el-rahman, h.a., s.a. salih, and a.m. abd el-wahab, effect of phosphoric acid on the electronic and diffusion proper-ties of the anodic passive layer formed on pb-1.7% sb grid of lead-acid batteries. journal of electrochemical science and technology, 2011. 2(2): p. 76-84. [13] voss, e., effects of phosphoric acid additions on the behaviour of the lead—acid cell: a review. journal of power sources, 1988. 24(3): p. 171-184. [14] meissner, e., phosphoric acid as an electrolyte additive for lead/acid batteries in electricvehicle applications. journal of power sources, 1997. 67(1-2): p. 135-150. [15] sternberg, s., v. branzoi, and l. apateanu, study of electrode processes in pb/h2so4+ additive systems. journal of power sources, 1990. 30(1-4): p. 177-183. [16] sternberg, s., et al., effect of h3po4 on the pbso4/pbo2 electrode in h2so4 solutions. electrochimica acta, 1987. 32(2): p. 349-351. [17] yazd, m.s., a. molazemi, and m.h. moayed, the effects of different additives in electrolyte of agm batteries on self-discharge. journal of power sources, 2006. 158(1): p. 705-709. [18] watson, h., storage battery maintenance and principles. facilities instructions, standards, and techniques. volume 3-6. 1991, bureau of reclamation, denver, co (united states). engineering div. [19] schilling, s., ensuring lead-acid battery performance with pulse technology. sae transactions, 2003: p. 360-364. [20] lam, l.t., et al., pulsed-current charging of lead/acid batteries—a possible means for overcoming premature capacity loss? journal of power sources, 1995. 53(2): p. 215-228. [21] jamali, a. h., samo, s., shaikh, s. a., hussain, t. and qaimkhani, m. a.. analytical analysis and performance characterization of hexagonal grid configuration of wet cell battery. international journal on emerging technologies, 2020, 11(5): 459–464. format template vol. 2, no. 2 | july december 2019 sjet | p-issn: 2616-7069 | e-issn: 2617-3115 | vol. 2 | no. 2 | © 2019 sukkur iba 36 techno-economic analysis of solar thermal water heaters in pakistan muhammad aitezaz hussain1 , mudasar rashid1, sobab khan1 and ahtesham rahim1 abstract: pakistan is in shortage of power due to gap in its supply and demand of energy. country’s energy and power sectors mainly depend upon the crude oil and fossil fuels in which natural gas is main source of energy in the domestic and commercial zones, yet due to the poor management and undiscovered reservoirs the demand of gas is also high and situation in the winter gets worse when the demand reaches to its peak. in contrast, pakistan industrial sector uses daily thousands of gallons of hot waters for its different processes and hot water mainly heated through conventional sources of energy. in this paper a sustainable and alternative approach has been adopted for these issues, the study has shown that the solar thermal energy can play a significant role in the pakistan’s geography. a newly introduced technology discussed is solar thermal water heaters. the analytical analysis has been carried out to compare conventional heaters (gas) with the solar water heaters. the cost analysis, energy saving, payback period was found by the mathematical approach. keywords: sustainable, solar thermal water heaters, fossil fuels, climate 1. introduction in today’s life, first and important entity to live life with peace is the availability of the energy to humans in every aspect. energy plays an important role in socioeconomic development of a country [1].the prime source of the energy on surface of earth is the natural resources of the world, that are facing the major problems such as depletion with time due to which its price is increasing day by day and most importantly they are bringing the climate changes in the environment very rapidly [2]. so taking into the account these issues it is highly 1 department of renewable energy engineering us. pakistan center for advanced study in energy, uet peshawar corresponding author: aitizazk36@gmail.com recommended by the researchers to switch towards the sustainable and environmental friendly and most importantly affordable sources of energy for fulfilling the energy needs [3]. from the last few years pakistan is also facing a severe energy shortage. this problem hugely effected the daily routine and most importantly the economy of the country. the shortfall is around 5000 to 6000 mw due to which the rural areas are going through 12 to 16 hours of load shedding while the urban areas are under 8 to 10 hour of electricity cutoff in summer and in winters the cities suffers 4 to 6 hours while villages bear 6 to 9 hours of load shedding [4, 5]. and if serious aitezaz (et al.), techno-economic analysis of solar thermal water heaters in pakistan (pp. 36 46) sukkur iba journal of emerging technologies sjet | volume 2 no. 2 july – december 2019 © sukkur iba university 37 initiatives on immediate bases aren’t taken this shortfall can increase in the upcoming years. fig. 1 shows the gap in supply and demand of electricity [6]. in this regard pakistan government has taken some serious steps to reduce the burden on conventional sources and introduce cheap sources by considering alternative means of energy like wind, hydro, solar pv and solar thermal energy due to its clean feathers [1, 7, 8]. potential of renewable energy in pakistan in very phenomenal due to its unique climate. pakistan lies mostly on sunny track so it receives the humongous amount of solar radiations annually shown in fig.3. solar energy is hugely spread and available in large amount throughout the country [2, 5]. on average pakistan receives 4.45 to 5.83 kwh/m2/day of the global radiation. even this minimum value of the average radiations 4.45 kwh/m2/day is quite higher than the world average radiation which is 3.61 kwh/m2/day. so it shows that pakistan can get enough benefits of the solar energy and can fulfill lot of its energy needs using this free available technology. the recording of sunshine in different parts of the country is being carried out by the isolation stations installed in big cities like lahore, karachi, peshawar, islamabad multan and quetta. fig. 2 shows direct normal solar radiation for summer in pakistan [9] . pakistan has taken some good steps towards the harnessing the renewable energies source after the 2006 renewable energy policy. some wind and solar power plants were started. feasibility reports were studied. fig. 2 shows the solar irradiance of the country which can be used for harnessing the solar energy at high level. in pakistan idea of solar thermal water heaters has been introduced for the first time on commercial scales at one of the leather industry located in lahore. the solar collectors were evacuated tubes collector type used 400m2 areas. the whole arrangement gives hot water up to 70 to 80℃ with 10℃ change to the inlet water. after the cost analysis it has been found out that the system has saved the cost of fuel up to 33 % annually. thus, after few years the setup was updated and extended. it means we can use it for our domestic scale too. and it can give us 60 to 70 % saving annually [5]. this technology is very beneficial, cost effective, and clean and needs very negligible maintenance. but due to its high capital cost as compared to the conventional heaters yet this technology isn’t fully developed [3, 4]. however, it is one of the most efficient technology and can be the best solution for the areas where natural gas isn’t available or deficient. also to the already decreasing natural resources and shortage of the power it is the best alternative [2]. fig. 1. forecast of demand and supply gap 2. litreture study 2.1 history the history of usage of solar heaters is very old. an inventor name clarence kemp in 1886 made a tank enclosed it in wooden box which was first commercial type solar water heater [10], these heaters are still used and are called integral collector storage type heaters. the solar water heating technology was gradually growing and in 1920 the flat plate solar waters heaters were introducing in florida and south california, and were prominently used in america till 1960. after 1960, the market of solar thermal water heaters came into the asia and japan adopted this technology first. after 1973 energy crisis the technology grew abruptly. aitezaz (et al.), techno-economic analysis of solar thermal water heaters in pakistan (pp. 36 46) sukkur iba journal of emerging technologies sjet | volume 2 no. 2 july – december 2019 © sukkur iba university 38 the developed countries like america, japan, india, canada australia, portugal, spain and united kingdom’s widely opened their market to this technology. spain became the 1st country which used the solar photovoltaics and 2nd country for solar thermal water heating technology in 2005 and 2006 respectively [11].the technology is now also very common in china and its products prices are very competitive in the market. today prices of the normal solar heater at china are us 235 $ which is approximately 80% less than the other countries prices. pie graph in fig.5 shows the global shares waters heaters market. fig. 2. solar irradiations for different cities of pakistan, (mj/m2) fig. 3. direct solar irradiance for different regions of pakistan in china around 30 million household uses solar water heaters due to the advanced aitezaz (et al.), techno-economic analysis of solar thermal water heaters in pakistan (pp. 36 46) sukkur iba journal of emerging technologies sjet | volume 2 no. 2 july – december 2019 © sukkur iba university 39 evacuated tube collectors properties that enables it be used in cloudy sky or in cold climate with freezing temperature [12]. 2.2. solar collectors something that can transform solar energy into the heat is supposed to be the solar thermal collectors. like the earth in self and the human body are also the clear examples of solar collectors. in more technical definition, the solar collector which helps to convert the incoming radiations of sun into useful form of heat and the example is warm air or water or any fluid. this principal can be simply realized by the hose pipe used to convey water for it and is also example of the simple unglazed collector. while minimizing heat loss from the system we used the glazed type solar collectors such as flat plat or evacuated tube collectors. the system can be further improved by using the concentrated collector with mirror which focuses the sun more on the collectors. the temperature up to 3500oc could be achieved in such method and the type is called solar furnace [13]. the performance of the solar collectors can be derived from actually taken heat q with the incoming solar radiation g. fig. 4. temperature impact on efficiencies of different solar collectors types so, the efficiency of the collector can be found by equation (1). ɳ = 𝑄 𝐺 (1) also fig.5 indicates that efficiency depends upon the operating temperature of the whole system [13]. 2.3 water heating mechanism the water heating mechanism is the circulation of water between the collectors and storage tank or area where the water is used. basically there are two types of heating water mechanism [2]. fig. 5. global shares of different countries in solar water heaters . 2.3.1 active system this method used pumps, controllers and sensors for the water flow. it can be direct flow mechanism or indirect. in direct flow mechanism as the name suggests the water flows between the collector and the storage tank without any use of the heat exchangers. they are used in the area and perform efficiently where the temperature falls rarely below the freezing. while in indirect heating method the pump force the water to flow between the collector then heat to exchanger a nonfreezing, nontoxic (propylene glycol) heating transfer fluid is used for this processes. they are used in the area where the temperature falls below the freezing in colder climate. the active water heating system is more effective and works well aitezaz (et al.), techno-economic analysis of solar thermal water heaters in pakistan (pp. 36 46) sukkur iba journal of emerging technologies sjet | volume 2 no. 2 july – december 2019 © sukkur iba university 40 than the passive system but due to high mechanical and controlling tools it’s more expensive than the latter one. fig. 6 shows the circulation of the water through direct and indirect active system [14, 15]. fig. 6. (a) direct active system (b) indirect active system 2.3.2 passive system in this mechanism the circulation of water is through natural convection process. they are also of two types [16] 2.3.2.1 integrating collector storage system it uses a tank sealed within an insulated box. these tanks are thin rectilinear shaped while the sides which have glass on its surface faces the sun. tank act as collector and at the same time a storage as well. the water from the tank then heat up through convection process and are available for the use [17]. 2.3.2.2 thermosyphon process based sytem this is also a natural process works on the simple physics principle, on the difference of the densities of the water. when the water gets hot by the sun, it losses weight and get raises [9]. while the colder waters come to the bottoms of the collector. the risen water is then transferring to the storage taken or the header tubes which must be installed above the collector and so we don’t need any tool or pumping system for the circulation of water in this system. the process of this system is shown in the fig.8. these are the low temperature heater ranges from 40 to 80oc above ambient temperature. so they are mostly used for the domestic purposes where the average hot temperature is from 40 to 50oc .a metallic plate absorber plate which is made of cu, steel or aluminum. mostly it is made of copper because of tits higher conductivity as compare to the other two. it’s also less corrosive [18]. fig. 7. passive solar water heater 2.4 types of solar collectors 2.4.1 flat plate collectors: in these collectors the plate or the sheet is coated or painted black for high absorption figure 8. tubes are attached or the integral part of the plate which contains the htf. the high transmittance glazing glass is used on the top of the plate. the system is enclosed in insulted box which prevent the heat loss from collectors backs and sides. they are fixed to the frame and so doesn’t need any tracking .the aitezaz (et al.), techno-economic analysis of solar thermal water heaters in pakistan (pp. 36 46) sukkur iba journal of emerging technologies sjet | volume 2 no. 2 july – december 2019 © sukkur iba university 41 efficiency of the flat plate solar collector is around 45% [19] . 2.4.2 evacuated tubes collectors these are latest technology based collectors and used on large scale for industrial applications where high temperature is required (up to 200oc) [18] . fig. 8. flat plat collector parts the figure 9 shows the structure wise parts. it consists of concentric glass tubes. the inner tubes with high absorptive coating contain the tubes having htf. the outer tube is made of borosilicate glass which maximizes the transmission of the solar radiation falling on it to the absorbing plates or tubes. with the efficiency 80%, it can reaches up to 120 degree above the ambient temperature [18].though the prices of evacuated tube collectors is high as compare to the former one. but due to some exceptional properties they are surpassing the market worldwide as shown in figure 10 [20]. fig. 9. evacuated tube collector parts the evacuation or the removal of the air results vacuum creation between two tubes which highly reduces the heat loss through convection or conduction. also, the curve shape permits the tubes to collects the radiations from the large angles and for long time of the day so high absorption of thermal energy occurs. due to these parameters it retains high temperature for long time. so it could be efficient in colder regions or at nights [21]. 3. methodology the study of the paper is based on a leather industry which uses the evacuated tube collectors for heating purposes in different process. on industrial scale the hot water usage in leather and textile process is more as compared to other industries. study says that on the average the daily requirement of hot water for a leather industry is 120,000 liter/day at a temperature of 70 to 80 degree centigrade [5]. aitezaz (et al.), techno-economic analysis of solar thermal water heaters in pakistan (pp. 36 46) sukkur iba journal of emerging technologies sjet | volume 2 no. 2 july – december 2019 © sukkur iba university 42 fig. 10. global percentage usage of solar collectors types 3.1. design requirements before going into the cost analysis. we should know about the technical and economic viability of a solar system which depend upon; how much sunshine is available throughout the year in the particular area. what would be the capital cost of the solar system? what is the price of the conventional fuel [22].the operational and maintenance cost of the system. what is the requirement of energy annually and how much would be the temperature of the hot water is desired. apart from these basic parameters, we also need the rate at which the conventional fuel prices escalate. taxes and other legislative issues must also be taken into the account while designing of the plant for the area. the evolution procedure is being approach by the following method [22]. a. estimating daily hot water load the daily hot water energy which could be consumed is given by: 𝐿 = 𝑀𝐶(𝑇ℎ𝑜𝑡 − 𝑇𝑙𝑜𝑤 ) (2) where l= daily hot water energy load in kwh/day m= mass of the water in kg/day c= specific heat of water =0.001167 kwh/kgoc. 𝑇ℎ𝑜𝑡 = the temperature of the hot water which is to be deliver to the load (oc) 𝑇𝑙𝑜𝑤 = the temperature of the cold water which has to be given to the collector at input (oc) typical hot water usage on domestic scale is 40 gallons/day/person and on industrial scale a leather industry needs approximately 31700 gallons for tanning washing and bleaching of leather [4]. a. solar energy resource collector should face south in northern hemisphere. tilt angle: latitude of the areas (±15o for winter and summer respectively). b. solar water heater system size the size of the solar water heater system can be deducted by the following formula: 𝐴𝐶 = 𝐿 𝑛𝑠𝑜𝑙𝑎𝑟 ×𝐼𝑚𝑎𝑥 (3) where; 𝐴𝐶 = area of collector in m 𝐿 = daily load in kwh/day 𝐼𝑚𝑎𝑥 = maximum insolation of the region 𝑛𝑠𝑜𝑙𝑎𝑟 = efficiency of solar water heater collector typically, we take = 50 % for evacuated tube and 40% for flat plate [22]. c. annual energy saving the amount of energy that could be saved annually is given by the formula: 𝐸𝑠 = (𝐴𝑐 × 𝐼𝑎𝑣𝑒 × 𝑛𝑠𝑜𝑙𝑎𝑟 ) 365 𝑛𝑏𝑜𝑖𝑙𝑒𝑟 (4) where 𝐼𝑎𝑣𝑒 = average solar radiation of the particular area (kwh/m2/day) 𝑛𝑏𝑜𝑖𝑙𝑒𝑟 = auxiliary heater efficiency the study says gas heater efficiency is = 0.43 to 0.86. we will assume it 0.57. aitezaz (et al.), techno-economic analysis of solar thermal water heaters in pakistan (pp. 36 46) sukkur iba journal of emerging technologies sjet | volume 2 no. 2 july – december 2019 © sukkur iba university 43 while the electric heater efficiency is = 0.77 to 0.97. and we will assume it 0.88. 3.2. cost of install solar system the installed system cost can be find out by the following relation [7]: 𝐶 = 𝐶𝑠𝑜𝑙𝑎𝑟 × 𝐴𝑐 (5) where, 𝐶 is the total cost of the install solar system and 𝐶𝑠𝑜𝑙𝑎𝑟 = cost of the solar per unit area (m2) while 𝐴𝑐 is the solar water heater system size respectively; a. cost saved annually the total cost in annual basis can be calculated by the relation given. 𝑆 = 𝐸𝑠 × 𝐶𝑒 (6) b. simple back period the simple back period of the system can be found out by formula given below. 𝑆𝑃𝐵 = 𝐶 𝑆 (7) where, 𝐶 is cost of installed the system and 𝑆 is the cost saved annually. 𝐶𝑒 is the cost of the conventional or auxiliary energy. c. tariff in pakistan domestic electricity average unit is pkr 15/kwh. while for industrial its average unit is pkr 22/ kwh. similarly, for gas sngpl current rates are domestic: [22] slab 1 = pkr 110/mmbtu for up to 1 hm3 slab 2 = pkr 220/ mmbtu over 1 to 3 hm3 slab 3 = pkr 600/mmbtu above 3 hm3 while for industrial consumers (leather industries) its rate is pkr 600/ mmbtu. in next section the mathematical equations explained in above section are applied on simple mathematical approach for industrial and domestic consumers both. 4. results and discussions 4.1. cost analysis for an industry as already mentioned leather industry almost needs 120,000 liters of hot water at 60 to 70oc. so the industry selected has a setup for water heating through solar water heaters and having capacity of 90,000 liter of hot water at 10oc rise to the incoming water. means if water comes at inlet at 50oc it will gets heated up to 60oc.applying the steps mentioned above: a. daily hot water load 𝐿 = 𝑀𝐶(𝑇ℎ𝑜𝑡 − 𝑇𝑙𝑜𝑤 ) (2) total mass of water in kg: 1 liter = 0.264 gallons also 90,000 liter in kg = 89972 kg (per day requirement of industry) so, m = 89972 kg c = 0.001167 kwh/kgoc while as the δt is 10 o c. putting the values in equation (2) we get. 𝐿 = 89972 × 0.001167 (10℃) l = 1050 kwh/day. b. system size 𝐴𝐶 = 𝐿 𝑛𝑠𝑜𝑙𝑎𝑟 ×𝐼𝑚𝑎𝑥 (3) putting the values in equation we get, 𝑛𝑠𝑜𝑙𝑎𝑟 = 0.50 and 𝐼𝑚𝑎𝑥 = 5.5 kwh/ m 2 for the region where the industry is located. 𝐴𝐶 = 1050 0.50 × 5.5 ac = 381 m2 c. annual energy saving 𝐸𝑠 = (𝐴𝑐 × 𝐼𝑎𝑣𝑒 × 𝑛𝑠𝑜𝑙𝑎𝑟 ) 365 𝑛𝑏𝑜𝑖𝑙𝑒𝑟 (4) aitezaz (et al.), techno-economic analysis of solar thermal water heaters in pakistan (pp. 36 46) sukkur iba journal of emerging technologies sjet | volume 2 no. 2 july – december 2019 © sukkur iba university 44 for gas heater we usually take the 𝑛𝑏𝑜𝑖𝑙𝑒𝑟 = 0.57 to know about how much energy has been saved per year, putting the corresponding values in equation (4), we get; 𝐸𝑠 = (381 × 5.25 × 0.50) 365 0.57 es = 640430 kwh/year, which is equal to 2,185.237866 mmbtu/year 1 ؞ kwh= 0.00341 mmbtu. d. cost of install solar system: 𝐶 = 𝐶𝑠𝑜𝑙𝑎𝑟 × 𝐴𝑐 (5) where csolar is the collector cost per unit area. in pakistan for the cost ranges from 25000 to 40000 rupees. we would consider an average rate of pkr 32000/= 𝐶 = 32000 × 381 c = pkr 12192000/ e. annual cost saving: if we are using the gas as our auxiliary heater source. then to find out how much cost has been saved we have the following equation: 𝑆 = 𝐸𝑠 × 𝐶𝑒 (6) at present as already mentioned above that pakistan commercial rates are 600/mmbtu [22]. putting the values in equation (6) 𝑆 = 2185.86 × 600 s = pkr 1300000/ year approximately. but as the gas is not sufficient enough to meet the demand of the country and there is obvious cut off of gas in winters. so the industries mostly relay on bio fuel like wood and crops residues as there conventional sources of heat producing which cost approximately rs 2200/to produces 1 ton of steam [23]. f. simple payback period: 𝑆𝑃𝐵 = 𝐶 𝑆 (7) spb = 12192000/1300000 spb ≈ 9 years. 4.2. cost analysis for a house to ensure safety on domestic scale, the solar water heaters must be used under the pressure relief value to supply and control the suitable temperature the mixing or sometimes the tempering vales must be used if there is any possibility of the temperature reaching to highest point .the figure 11 shows the typical two tank solar water heater collection in homes having the acceptable vales and pipe connections [18]. the study says that the average use of hot water for one adult person per day is 40 gal/day [22]. hence for 4 family members’ at least 160 gal/day would be required. fig. 11. figure 11: flow of water in domestic solar water heating system. gas water heater can have storage for a time being or it could be used for instantaneous delivery. load of water in kg /day would 160 gallons of water = 606 kg/ day. let the inlet is 18℃ and the outlet we need 50℃ .so applying the steps as from equation (1); l = 606 × 0.001167(50℃-18℃) l = 22.6 kwh/day now as 1kwh= 0.00341 mmbtu so in mmbtu the total load would be = 0.077 mmbtu from equation (3); ac = (22.6÷0.50) × 5.5 ac= 8.2 m2 aitezaz (et al.), techno-economic analysis of solar thermal water heaters in pakistan (pp. 36 46) sukkur iba journal of emerging technologies sjet | volume 2 no. 2 july – december 2019 © sukkur iba university 45 from equation 4: es = (8.2×5.25×0.50×365) ÷ 0.57 es = 13783.55 kwh/year and in mmbtu it would be = 47 units 1 ؞ kwh = 0.00341 mmbtu as already mention that the domestic slabs from sngpl the average mmbtu is around pkr 310/ the total cost saving on yearly basis would be pkr 14570/ for 4 family members on domestic scale single unit of the 300-liter capacity is enough. that is easily available in market from 30,000 to 60,000 depending on the quality and type and the average cost of single evacuated tube collector could be 40,000/300lit. taking the labor and other tooling cost (storage tank pipes etc.) cost may reach to 50,000 [8]. so, for the final cost simple payback period would be: s = 50,000÷14570 ≈ 3.5 years. 5. conclusion two commercially available solar thermal heaters have been investigated, analyzed and compare with the conventional water heating system. from above discussion we can conclude that evacuated tubes heaters are more efficient due to its thermal insulated glass. solar thermal water heater of the lather industry has been mathematically investigated and compared with that of its conventional gas heaters, wherein 2185 units per year mmbtu have been saved. moreover, for average house of four members is also examined wherein solar thermal system saved 47 units per year mmbtu. additionally, solar thermal water heaters optimally contribute to our ecosystem by significantly reducing carbon footprint compared to conventional water heaters. on industrial scale the solar thermal water heating system has more viability in the sense of economics for larger use of collectors. solar thermal water heaters have very huge potential in the northern areas of pakistan and hot regions of baluchistan where there is very little or no gas and also have relatively high insolation up to average of 8 kwh/day/m2. moreover, industries where water is heated by conventional heating system can contribute in the energy saving by incorporating solar thermal heating system and consequently reduce the burden of energy shortage in country like pakistan. reference [1] m. h. baloch, g. s. kaloi, and z. a. memon, "current scenario of the wind energy in pakistan challenges and future perspectives: a case study," energy reports, vol. 2, pp. 201-210, 2016. [2] t. aized, m. shahid, a. a. bhatti, m. saleem, and g. anandarajah, "energy security and renewable energy policy analysis of pakistan," renewable and sustainable energy reviews, vol. 84, pp. 155-169, 2018. [3] m. h. baloch, j. wang, g. s. kaloi, a. a. memon, a. s. larik, and p. sharma, "techno‐economic analysis of power generation from a potential wind corridor of pakistan: an overview," environmental progress & sustainable energy, vol. 38, no. 2, pp. 706-720, 2019. [4] m. h. baloch et al., "hybrid energy sources status of pakistan: an optimal technical proposal to solve the power crises issues," energy strategy reviews, vol. 24, pp. 132-153, 2019. [5] i. ullah, m. g. rasul, a. sohail, m. islam, and m. ibrar, "feasibility of a solar thermal power plant in pakistan," in thermal power plantsadvanced applications: intechopen, 2013. [6] r. p. butt, i. a. chaudhry, i. zahid, and m. a. shakir, "enhancement of wind power generation in pakistan," science international, vol. 27, no. 6, 2015. aitezaz (et al.), techno-economic analysis of solar thermal water heaters in pakistan (pp. 36 46) sukkur iba journal of emerging technologies sjet | volume 2 no. 2 july – december 2019 © sukkur iba university 46 [7] m. hussain baloch, d. ishak, s. tahir chaudary, b. ali, a. asghar memon, and t. ahmed jumani, "wind power integration: an experimental investigation for powering local communities," energies, vol. 12, no. 4, p. 621, 2019. [8] b. memon, m. h. baloch, a. h. memon, s. h. qazi, r. haider, and d. ishak, "assessment of wind power potential based on raleigh distribution model: an experimental investigation for coastal zone," engineering, technology & applied science research, vol. 9, no. 1, pp. 3721-3725, 2019. [9] f. muhammad, m. w. raza, s. khan, and f. khan, "different solar potential co-ordinates of pakistan," innovative energy & research, vol. 6, no. 2, 2017. [10] p. john, "solar evolution-the history of solar energy," ed: california: california solar center, 2002. [11] j. l. sawin et al., "renewables 2010global status report," 2010. [12] a. gastli and y. charabi, "solar water heating initiative in oman energy saving and carbon credits," renewable and sustainable energy reviews, vol. 15, no. 4, pp. 1851-1856, 2011. [13] j. a. duffie and w. a. beckman, solar engineering of thermal processes. john wiley & sons, 2013. [14] a. shafieian, m. khiadani, and a. nosrati, "strategies to improve the thermal performance of heat pipe solar collectors in solar systems: a review," energy conversion and management, vol. 183, pp. 307-331, 2019. [15] m. hanoin, n. mohammed, m. arris, a. bakar, n. mokhtar, and a. razak, "fabrication and performance evaluation of integrated solar-driven membrane distillation system with serpentine-shape of flat plate solar collector for seawater desalination," journal of applied membrane science & technology, vol. 23, no. 3, 2019. [16] s. a. kalogirou, "chapter 5. solar water heating systems," solar energy engineering, second ed., academic press, boston, p. 257, 2014. [17] g. sootha, "solar thermal applications," in physics and technology of solar energy: springer, 1987, pp. 467-473. [18] m. hossain et al., "review on solar water heater collector and thermal energy performance of circulating pipe," renewable and sustainable energy reviews, vol. 15, no. 8, pp. 3801-3812, 2011. [19] n. benz, m. gut, and t. beikircher, "solar process heat with nonconcentrating collectors for food industry," in proceedings of ises solar world congress, 1999. [20] s. h. worldwide, "solar heating and cooling programme," international energy agency, 2016. [21] g. s. chandraprabu venkatachalam, "evacuated tube solar collectors: a review," (in english), international journal of scientific engineering and research (ijser), review vol. volume 6, no. 12, december 2018, p. 4, 2018. [22] r. taylor, "solar thermal technology and applications," in national renewable energy laboratory, briefing slides for naemi solar electric and thermal training workshop, 2006, pp. 27-29. [23] "saddiq leather works " https://www.siddiqleather.com/ (accessed.) https://www.siddiqleather.com/ an energy efficient crypto suit for secure underwater sensor communication using genetic algorithm vol. 5, no. 1 | january – june 2022 sjet | p-issn: 2616-7069 |e-issn: 2617-3115 | vol. 5 no. 1 january – june 2022 54 multi-scale pooling in deep neural networks for dense crowd estimation ali raza radhan1, fareed ahmed jokhio2, ghulam hussain1,3, kamran javed4, arsalan ahmed1 abstract: state-of-the-art-methods for counting persons in dense crowded places lack in estimating accurate crowd density due to following reasons. they typically apply the same filters over a complete image or over big image patches. only then the perspective distortion can be compensated by estimating local scale. it is achieved by training an additional classifier with the optimal kernel size chosen from limited choices. these methods are restricted to the context they are applied on because they are not end-to-end trainable; cannot justify quick scale changes because they allocate a single scale to big image patches; and can only utilize a narrow range of receptive fields for the networks to be of a feasible size. in this study, we bring in an end-toend trainable deep architecture that merges features achieved from multiple kernels of different sizes and learns various essential features such as quick scale changes and to utilize the right context at each image location. this technique flexibly encodes scale of related information to precisely predict crowd density. the training and validation loss of the proposed approach is 5% and 4% lower than the state-of-the-art context aware method, respectively. keywords: perspective distortion, local scale, image patches, crowd counting, deep learning. 1 introduction crowd counting has become an interesting topic in the recent years for researchers due to its broad applications, including crowd monitoring, traffic control, public safety, and event planning, video surveillance and city management. over the last few years, the density map generation methods have been developed to count people in a scene by training regressors to estimate people density per unit area and get total number of counts by integration without detecting people individually. currently deep learning methods [28-33] have become prevailing tool for crowd counting, due to powerful learning ability of 1dept. electronic engineering, quaid-e-awam university, larkana, pakistan. 2dept. computer system engineering, quaid-e-awam university, nawabshah, pakistan 3dept. electronic engineering, sungkyunkwan university, suwon, south korea 4national centre of artificial intelligence (ncai), saudi data and artificial intelligence corresponding author: fajokhio@quest.edu.pk convolutional neural networks (cnns). although crowd counting algorithms have been broadly examined by previous methods [20-22, 2833], but handling large density variance in crowd images which causes occlusion and perspective distortion that still remained a challenging problem. as illustrated in fig.1, the densities of a crowd vary significantly from low crowd (e.g. venice dataset) to extremely dense crowd (shanghai part a dataset). such large variation in density of people is a great challenge for cnn models and creates problems for predicting accurate density map. most deep learning-based approaches [30-36] use same filters and mailto:fajokhio@quest.edu.pk multi-scale pooling in deep neural networks for dense crowd estimation (pp. 54 63) sukkur iba journal of emerging technologies sjet | vol. 5 no. 1 january – june 2022 55 pooling operations on a complete image. these depend upon fix sizes of receptive fields. however, one ought to alter receptive field size over an image to get better results. stunning advancement has been attained by learning a density map by designing multi scale structures [39] or accumulating multi scale features [40,41], which shows capacity to manage with density variation is tuff for crowd counting approaches and remains a huge challenge. figure 2 compares the mean absolute error of several techniques on three standard benchmark crowd counting datasets having different crowd densities. result indicates the strength of proposed method to high scale variance. low medium high fig. 1. crowd types such large variation in density of people is a great challenge for cnn models and creates problems for predicting accurate density map. most deep learning-based approaches [30-36] use same filters and pooling operations on a complete image. these depend upon fix sizes of receptive fields. however, one ought to alter receptive field size over an image to get better results. stunning advancement has been attained by learning a density map by designing multiscale structures [39] or accumulating multiscale features [40,41], which shows capacity to manage with density variation is tuff for crowd counting approaches and remains a huge challenge. figure 2 compares the mean absolute error of several techniques on three standard benchmark crowd counting datasets having different crowd densities. result indicates the strength of proposed method to high scale variance. in this paper, we introduce a deep learning method that gets features from different receptive field sizes and learn the importance of each feature at different image locations and accounts for rapid scale changes. our method can alleviate the problem of density variation, occlusion, and perspective distortion by using multi-scale pooling operation and give better results than other state-of-art methods. this is contrast to crowd counting methods that work on the density variation as in [19, 42], but different only in the loss function as we get the accurate multi-scale features with minimum error. experiments are done on several standard crowds counting benchmark datasets such as shanghaitech part a, part b and venice which show large density variation as shown in figure 1. 2 letrature review most of the initial research was centered on detection-based crowd counting, where rectangular bounding boxes were used to detect persons in the scene [1] and this information was used to count the number of persons [2]. people are counted either by whole body detection or by different body parts-based detection. same class detection techniques [3,4] generally are conventional pedestrian detection ways which train a multi-scale pooling in deep neural networks for dense crowd estimation (pp. 54 63) sukkur iba journal of emerging technologies sjet | vol. 5 no. 1 january – june 2022 56 classifier using attributes (such as haar wavelets [5], histogram-oriented gradients [4], edgelet [6] and shapelet [7]) taken out from a full body. several learning methods such as support vector machines, boosting [8] and random forest [9] have been used with different level of success. though fruitful in small scale crowd scenes, these methods are badly affected in dense crowd places. analysts have endeavored to address this issue by embracing part-based detection methods [10, 11], where one applies boosted classifiers for particular body parts such as the head and shoulder to approximate the people counts in that specific area [2]. though part-based detectors were used to reduce the problems of overlapping, these mechanisms had not fruitful results in the presence of highly congested crowds and high background litter. fig. 2. the performance comparison of the state-of-the-art methods to solve these problems researchers tried to count by regression where they apply a mapping between features brought out from local image patches to their researcher’s counts [12, 13]. by counting using regression, these strategies dodge reliance on teaching detectors which could be a generally complex task. in recent research, idrees et al. [23] recognized that in congested crowds, no any detection method is effective enough to give precise data for counting people due to problems of overlapping, low quality images and perspective distortion. furthermore, they noticed that there exists a spatial relationship that can be utilized to oblige the count approximation in adjacent local regions. with these ideas in mind, they suggest finding features using various methods that gather different information. by treating thickly populated crowds of people as irregular and non-homogeneous surface, they applied multi-scale pooling in deep neural networks for dense crowd estimation (pp. 54 63) sukkur iba journal of emerging technologies sjet | vol. 5 no. 1 january – june 2022 57 fourier analysis along with head detections and scale-invariant feature transform (sift) interest point based counting in local adjacent regions. the three sources, i.e., fourier, interest points and head detection are then merged with their respective confidences and counts at localized patches are determined independently. as the previous methods were successful in addressing the problems of occlusion and clutter, they mostly neglected important spatial information as they were regressing on the global count. in variance, lempitsky et al. [24] proposed a method to learn a linear mapping between local patch features and object density maps, thereby absorbing spatial information in the learning procedure. perceiving that it is hard to learn a linear mapping, pham et al. [25] proposed a method to learn a non-linear mapping between local patch features and density maps. they take multiple image patches using random forest regression to vote for densities of various target objects to learn a non-linear mapping. similar to the above technique, wang and zou [26] proposed a fast method for density estimation based on subspace learning viewing the computational complication point of view of the existing methods. in a recent approach, xu and qiu [27] perceiving that the existing crowd density estimation strategies utilized a smaller set of features results in limiting their capability to perform better. they put forward a method to increase the accuracy of crowd density estimation by utilizing a large set of features. as the regression methods used by previous methods (based on gaussian process regression or ridge regression) are computationally complex and are not able to operate very high-dimensional features, they utilized random forest as the regression model whose tree structure is speedy and flexible. unlike conventional methods to random forest construction, they inserted random projection in the tree nodes to tackle the problem of dimensionality and to introduce randomness in the tree structure. now density-based counting methods are mostly superseded by convolutional neural networks-based methods where instead of looking at the patches of an image, researchers form an end-to-end regression method using cnns. wang et al. [28] applied cnns firstly for the task of crowd density estimation. wang et al. gave an end-to-end deep cnn regression model for counting persons from images in highly dense crowds. in addition, to minimize false responses background like trees and buildings in the images, training data is increased with extra negative samples having ground truth count is fixed as zero. in another approach, fu et al. introduced to divide the image into one of the five categories: very high density, high density, medium density, low density and very low density rather than estimating density maps, they utilized a combination of two classifiers to acquire boosting in which the first classifier samples misclassified images and the other one reclassifies rejected samples. the approach of [29, 30] utilizes image patches taken out at multiple scales as source to a multi stream network. they then either combine the features for final density prediction [29] without continuous scale changes or introduce an adhoc term in the training loss function [30] predict consistency across scales forcibly. this, however, does not take contextual information into the features achieved by the algorithm, so has limited effect. whereas approach [31] learns multiscale features, by utilizing various receptive fields, they merge all of these features to estimate the density. while the earlier approaches account for scale, they neglect the reality that the suitable scale changes smoothly over the image should be controlled dynamically. this was proposed in [32] by weighting various density maps generated from input images at different scales. as the density map at each scale just relies upon features extracted from a specific scale, and consequently be ruined by the absence of versatile-scale reasoning. here, we content that one should rather extract features at various scales and figure out how to adaptively merge them. while this, basically was also the inspiration of [33] , which train an additional classifier to dole out the best receptive field for each image patch, these multi-scale pooling in deep neural networks for dense crowd estimation (pp. 54 63) sukkur iba journal of emerging technologies sjet | vol. 5 no. 1 january – june 2022 58 techniques stay restricted in many significant manners. firstly, they depend on classifiers, which need pre-training the network before training the classifier, and in this way it is not end-to-end trainable. secondly, they commonly assign a single scale to a whole image patch that can still be large and in this manner don't represent quick scale changes. lastly, the range of receptive field sizes they reliance remain limited in part because using much bigger ones would need using more complex architectures, which may be difficult to train given sort of networks being used. in this study, we bring in an end-to-end trainable deep architecture that merges features achieved from multiple kernels of different sizes and learns various essential features such as quick scale changes and to utilize the right context at each image location. this technique flexibly encodes scale of related information to precisely predict crowd density. the training and validation loss is relatively low than above methods. 3 method 3.1 overview as discussed above, we target the perspective distortion problem in crowd counting methods where density of people varies from low to extreme level. for decreasing the training and validation loss and to improve the generalization of the model with density variation, we trained it on optimal number of epoch and batch size to get the final density map. fig. 3. the proposed methodology 3.2 scale learning module we aim to generate an estimated density map that is very similar to ground-truth density map of the given set of m training images with corresponding ground-truth density maps. images are given to initial point of our network having first ten layers of pretrained vgg-16 network to get vgg feature maps as shown in fig.2. these vgg features are the base to our learning-scale model. as discussed earlier in section 2, vgg-16 network use same filters and pooling operations on a complete image and depends upon fix sizes of receptive fields. so, it is less efficient in rapid scale change scenarios. to solve this, we alter receptive field size over an image to get learning-scale features by applying multiscale pooling 1x1, 2x2, 3x3 and 6x6 on vgg features. this forms a pyramid structure. each pooling multi-scale pooling in deep neural networks for dense crowd estimation (pp. 54 63) sukkur iba journal of emerging technologies sjet | vol. 5 no. 1 january – june 2022 59 feature shows a density map, hence four different densities extract information from the given image. these multi-scale densities are then up sampled to the size of convolution layers by linear interpolation and finally combined to give the weighted features. in the end weighted features are concatenated with vgg features to predict the final density map of underlying image as shown in figure 3. scale learning network is illustrated in figure 3. rgb images are at input to a front network that contains the first 10 layers of the vgg-16 network. the resulting vgg features are organized in blocks of various sizes by average pooling succeeded by a 1×1 convolutional layer. they are then up sampled back to the original feature size to form the weighted features. contrast or weighted features are further utilized to memorize the weights for the learning-scale features that are then fed to a back-end network to deliver the ultimate density map. 3.3 training details and loss function our network is end-to-end trainable which involves l2 loss defined as 𝐿(𝜎) = 1 2𝐵 ∑ { 𝐷𝑖 𝑔𝑡 − 𝐷𝑖 𝑝𝑟𝑒 } 2 2 𝐵𝑖=1 () where b is the batch size, 𝝈 is the nonlinear mapping parameter that maps an input image 𝑰i to a predicted density map 𝑫𝒊 𝒑𝒓𝒆 . 𝑫𝒊 𝒈𝒕 is the ground-truth density map that we get as in [19] by convolving an image having ones at people head’s locations and zeros elsewhere with a gaussian kernel 𝑵𝒈𝒕 (𝒑\𝝁, 𝜹𝟐) we have ∀𝑝 ∈ 𝐼𝑖 , 𝐷𝑖 𝑔𝑡 (p\𝐼𝑖 ) = ∑ 𝑁𝑔𝑡𝑐𝑖𝑗=1 (𝑝\𝜇 = 𝑃𝑖 𝑗 , 𝛿 2) () where 𝝁 and 𝜹 are the mean and standard deviation of the normal distribution. to reduce the loss, we apply stochastic gradient descent with batch size 1 for shanghaitech part_a dataset because it has various size images and got impressive results after training the model for 150 epochs. for other two venice and shanghaitech_part_b fixed image size datasets, we use adam with batch size 16 and trained the model for 100 epochs 4 experiments 4.1 evaluation matrices we apply two standard error terms, i.e. mean absolute error (mae) and mean squared error (mse) for evaluation purpose and compare our results with other methods. these are defined as 𝑀𝐴𝐸 = 1 𝐾 ∑ |𝑥𝑖 − �̂�𝑖 | 𝐾 𝑖=1 , 𝑀𝑆𝐸 = √ 1 𝐾 ∑ (𝑥𝑖 − �̂�𝑖 ) 2𝐾 𝑖=1 , () where k is the total number of images of test images, 𝒙𝒊 represents the ground-truth and 𝒙𝒊 is the predicted number of people in the 𝒊 𝒕𝒉 image. 4.2 benchmark datasets and groundtruth data we took three standard benchmark datasets including shanghaitech part_a, shanghaitech part_b and venice to compare our method with other approaches. shanghaitech [27]. the shanghaitech crowd counting dataset comprises of 1198 images with approximately 330,165 people in them. it is divided in two parts shanghaitech part_a with 482 images which are randomly taken from internet and shanghaitech part_b having 716 images taken from busy streets of metropolitan area in shanghai city. in part_a 300 images and in part_b 400 images are reserved for training set. the remaining images of both parts are used for testing purposes. the ground-truth density maps for part_a were generated by adaptive gaussian kernels and for part_b by fixed kernels. venice [19]. venice dataset contains 167 fixed size 1280x720 resolution images from piazza san marco in venice. in this dataset 80 images forms a training data set, and 87 images are used for testing purpose. the images of venice dataset are more calibrated than multi-scale pooling in deep neural networks for dense crowd estimation (pp. 54 63) sukkur iba journal of emerging technologies sjet | vol. 5 no. 1 january – june 2022 60 shanghaitech. the ground-truth density maps are generated by fixed gaussian kernels as in shanghaitech part_b data set. 4.3 ablation study ablation study is mainly performed on shanghaitech and venice datasets, as there could be the more problem of rapid scale change due to density variation. here we confirm the benefits of specific features. table 1 shows comparison of mean absolute error and root mean square error of different approaches on three standard benchmark crowd counting datasets having people density variation. results in figure 4 indicate the strength of proposed method on low, medium, and high types of crowds. table i. comparative results on the venice dataset & shanghaitech dataset variation in crowd counting. we summed up venice shanghai part-a shanghai part-b method mae rmse mae rmse mae rmse zhang et al.[32] 181.8 277.7 32.0 49.8 mcnn [33] 145.4 147.3 110.2 173.2 26.4 41.3 switch-cnn[34] 52.8 59.5 90.4 135.0 21.6 33.4 cp-cnn[36] 73.6 106.4 20.1 30.1 acscp[42] 75.7 102.7 17.2 27.4 liu et al.[37] 73.6 112.0 13.7 21.4 d-convnet[41] 73.5 112.3 18.7 26.0 ig-cnn[31] 72.5 118.2 13.6 21.1 ic-cnn[43] 68.5 116.2 10.7 16.0 csrnet[38] 35.8 50.0 68.2 115.0 10.6 16.0 multi-scale pooling in deep neural networks for dense crowd estimation (pp. 54 63) sukkur iba journal of emerging technologies sjet | vol. 5 no. 1 january – june 2022 61 sanet[30] 67.0 104.5 8.4 13.6 context aware[19] 20.5 29.9 62.3 100.0 7.8 12.2 ours approach 19.8 29.3 61.5 100.0 7.2 12.0 fig. 4. the performance of the proposed approach on three different density level scenes for crowd density estimation 5 conclusion and future perspectives in this paper, we propose a learning scale model by applying multi-scale pooling network to solve the problem of density four different scale density maps of an image to generate the final one. experiments were performed on three different standard benchmark datasets having density variations and the generalization ability of the model was quite vgg: 132 ours mspn: 174 gt: 184 vgg: 223 ours mspn: 273 gt: 285 vgg: 2810 ours mspn: 2221 gt: 2333 multi-scale pooling in deep neural networks for dense crowd estimation (pp. 54 63) sukkur iba journal of emerging technologies sjet | vol. 5 no. 1 january – june 2022 62 impressive than other state-of-art methods. these datasets were formed by fixed cameras, so in future we will work on the images taken from moving cameras e.g. drones. we will enhance our model to process consecutive images and their groundtruth data simultaneously funding: this research received no external funding. conflicts of interest: the authors declare no conflict of interest. references [1] dollar, p., wojek, c., schiele, b., perona, p., 2012. pedestrian detection: an evaluation of the state of the art. ieee transactions on pattern analysis and machine intelligence 34, 743–761. [2] li, m., zhang, z., huang, k., tan, t., 2008. estimating the number of people in crowded scenes by mid based foreground segmentation and headshoulder detection, in: pattern recognition, 2008. icpr 2008.19th international conference on, ieee. pp. 1–4. [3] leibe, b., seemann, e., schiele, b., 2005. pedestrian detection in crowded scenes, in: computer vision and pattern recognition, 2005. cvpr 2005. ieee computer society conference on, ieee. pp. 878–885. [4] tuzel, o., porikli, f., meer, p., 2008. pedestrian detection via classification on riemannian manifolds. ieee transactions on pattern analysis and machine intelligence 30, 1713–1727. [5] viola, p., jones, m.j., 2004. robust real-time face detection. international journal of computer vision 57, 137–154. [6] wu, b., nevatia, r., 2005. detection of multiple, partially occluded humans in a single image by bayesian combination of edgelet part detectors, in: computer vision, 2005. iccv 2005. tenth ieee international conference on, ieee. pp. 90–97. [7] sabzmeydani, p., mori, g., 2007. detecting pedestrians by learning shapelet features, in: computer vision and pattern recognition, 2007. cvpr’07. ieee conference on, ieee. pp. 1–8. [8] viola, p., jones, m.j., snow, d., 2005. detecting pedestrians using patterns of motion and appearance. international journal of computer vision 63, 153–161. [9] gall, j., yao, a., razavi, n., van gool, l., lempitsky, v., 2011. hough forests for object detection, tracking, and action recognition. ieee transactions on pattern analysis and machine intelligence 33, 2188–2202. [10] felzenszwalb, p.f., girshick, r.b., mcallester, d., ramanan, d., 2010. object detection with discriminatively trained partbased models. ieee transactions on pattern analysis and machine intelligence 32, 1627–1645. [11] wu, b., nevatia, r., 2007. detection and tracking of multiple, partially occluded humans by bayesian combination of edgelet based part detectors. international journal of computer vision 75, 247– 266. [12] chan, a.b., vasconcelos, n., 2009. bayesian poisson regression for crowd counting, in: 2009 ieee 12th international conference on computer vision, ieee. pp. 545–551. [13] ryan, d., denman, s., fookes, c., sridharan, s., 2009. crowd counting using multiple local features, in: digital image computing: techniques and applications, 2009. dicta’09., ieee. pp. 81–88. [14] babu sam, d., surya, s. and venkatesh babu, r., 2017. switching convolutional neural network for crowd counting. in proceedings of the ieee conference on computer vision and pattern recognition (pp. 5744-5752). [15] zhang, l., shi, m. and chen, q., 2018, march. crowd counting via scale-adaptive convolutional neural network. in 2018 ieee winter conference on applications of computer vision (wacv) (pp. 1113-1121). ieee. [16] chen, j., su, w. and wang, z., 2020. crowd counting with crowd attention convolutional neural network. neurocomputing, 382, pp.210-220. [17] zhang, y., zhou, d., chen, s., gao, s. and ma, y., 2016. single-image crowd counting via multicolumn convolutional neural network. in proceedings of the ieee conference on computer vision and pattern recognition (pp. 589-597). [18] sam, d.b. and babu, r.v., 2018, april. topdown feedback for crowd counting convolutional neural network. in thirtysecond aaai conference on artificial intelligence. [19] liu, w., salzmann, m. and fua, p., 2019. contextaware crowd counting. in proceedings of the ieee/cvf conference on computer vision and pattern recognition (pp. 5099-5108). [20] zhang, c., li, h., wang, x. and yang, x., 2015. cross-scene crowd counting via deep convolutional neural networks. in proceedings of the ieee conference on computer vision and pattern recognition (pp. 833-841). [21] hu, y., chang, h., nian, f., wang, y. and li, t., 2016. dense crowd counting from still images with convolutional neural networks. journal of visual communication and image representation, 38, pp.530-539. [22] boominathan, l., kruthiventi, s.s. and babu, r.v., 2016, october. crowdnet: a deep convolutional network for dense crowd counting. in proceedings of the 24th acm international conference on multimedia (pp. 640-644). multi-scale pooling in deep neural networks for dense crowd estimation (pp. 54 63) sukkur iba journal of emerging technologies sjet | vol. 5 no. 1 january – june 2022 63 [23] idrees, h., saleemi, i., seibert, c., shah, m., 2013. multi-source multiscale counting in extremely dense crowd images, in: proceedings of the ieee conference on computer vision and pattern recognition, pp. 2547–2554. [24] lempitsky, v., zisserman, a., 2010. learning to count objects in images, in: advances in neural information processing systems, pp. 1324–1332. [25] pham, v.q., kozakaya, t., yamaguchi, o., okada, r., 2015. count forest: co-voting uncertain number of targets using random forest for crowd density estimation, in: proceedings of the ieee international conference on computer vision, pp. 3253– 3261. [26] wang, y., zou, y., 2016. fast visual object counting via example-based density estimation, in: image processing (icip), 2016 ieee international conference on, ieee. pp. 3653–3657. [27] xu, b., qiu, g., 2016. crowd density estimation based on rich features and random projection forest, in: 2016 ieee winter conference on applications of computer vision (wacv), ieee. pp. 1–8. [28] wang, c., zhang, h., yang, l., liu, s., cao, x., 2015. deep people counting in extremely dense crowds, in: proceedings of the 23rd acm international conference on multimedia, acm. pp. 1299–1302. [29] daniel onoro-rubio and roberto j. l´opezsastre. towards perspective-free object counting with deep learning. in european conference on computer vision, pages 615– 629, 2016. [30] xinkun cao, zhipengwang, yanyun zhao, and fei su. scale aggregation network for accurate and efficient crowd counting. in european conference on computer vision, 2018. [31] deepak babu sam, neeraj n. sajjan, r. venkatesh babu, and mukundhan srinivasan. divide and grow: capturing huge diversity in crowd images with incrementally growing cnn. in conference on computer vision and pattern recognition, 2018. [32] cong zhang, hongsheng li, xiaogang wang, and xiaokang yang. cross-scene crowd counting via deep convolutional neural networks. in conference on computer vision and pattern recognition, pages 833–841, 2015. [33] yingying zhang, desen zhou, siqin chen, shenghua gao, and yi ma. single-image crowd counting via multi-column convolutional neural network. in conference on computer vision and pattern recognition, pages 589– 597,2016. [34] deepak babu sam, shiv surya, and r. venkatesh babu. switching convolutional neural network for crowd counting.in conference on computer vision and pattern recognition, page 6, 2017. [35] feng xiong, xinjian shi, and dit-yan yeung. spatiotemporal modeling for crowd counting in videos. in international conference on computer vision, pages 5161–5169, 2017. [36] vishwanath a. sindagi and vishal m. patel. generating high-quality crowd density maps using contextual pyramid cnns. in international conference on computer vision,pages 1879–1888, 2017. [37] xialei liu, joost van de weijer, and andrew d. bagdanov. leveraging unlabeled data for crowd counting by learning to rank. in conference on computer vision and pattern recognition, 2018. [38] yuhong li, xiaofan zhang, and deming chen. csrnet: dilated convolutional neural networks for understanding the highly congested scenes. in conference on computer vision and pattern recognition, 2018. [39] wei liu, dragomir anguelov, dumitru erhan, christianszegedy, scott e. reed, cheng-yang fu, and alexander c.berg. ssd: single shot multibox detector. in european conference on computer vision, 2016. [40] vijay badrinarayanan, alex kendall, and roberto cipolla. segnet: a deep convolutional encoderdecoder architecture for image segmentation. arxiv preprint, 2015. [41] zenglin shi, le zhang, yun liu, and xiaofeng cao. crowd counting with deep negative correlation learning. in conference on computer vision and pattern recognition, 2018. [42] zan shen, yi xu, bingbing ni, minsi wang, jianguo hu, and xiaokang yang. crowd counting via adversarial cross-scale consistency pursuit. in conference on computer vision and pattern recognition, 2018. [43] viresh ranjan, hieu le, and minh hoai. iterative crowd counting. in european conference on computer vision,2018 format template vol. 3, no. 2 | july december 2020 sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 90 teaching oral communication skills to healthcare personnel using communicative language teaching technique faiza khadim arain1,,hira khadim2, munsif ali jatoi3,hina manzoor2 abstract: the importance of communication skills has long been established in the medical and nursing education. although such skills are taught in medical and nursing undergraduate curriculum around the world, but less attention is being paid towards the communication skills of healthcare personnel in pakistan. the primary focus of this study is to determine whether the communicative language teaching (clt) technique had an effect on oral english communication skills of nursing students. this quasi-experimental study was conducted at undergraduate nursing students. purposive sampling was employed. a pre-test, based on role-plays, was conducted on the baseline status of students followed by a sixteen-hour course. the same roleplay scenarios were given as a post-test. participants were assessed through rubrics adapted using proficiency descriptor and cambridge english assessment scale. the wilcoxon signedrank test was employed to compare scores obtained from pre-test and post-test. the result revealed that the communication language teaching technique had a significant effect on the oral english communication skills of nursing students. keywords: oral communication skill; communicative language teaching technique; roleplays; statistical tests; healthcare; nursing education 1. introduction language is often defined as a communicative tool that helps to exchange ideas and, thoughts. it is widely known that human beings learn their mother tongue in their natural situation. similarly, the same is the case with foreign languages. it can easily be learnt in a friendly and comfortable situation where language learners are encouraged to participate naturally. in the learning process, both teachers and learners are equally involved. therefore, the teaching process should be as much interactive as possible. in [1], it was claimed for effective 1 department of management sciences, barrett hodgson university, karachi, sindh, pakistan 2 ned university of engineering and technology, karachi, sindh, pakistan 3 department of biomedical engineering, barrett hodgson university, karachi, sindh, pakistan corresponding author: munsif.jatoi@bhu.edu.pk teaching, the methods employed to communicate with the students, should be effective. in this regard, the communicative language teaching approach is considered as the best option to teach foreign languages. in many schools, colleges and universities, more antiquated teaching methodologies (such as grammar-translation or audio-lingual) are still being employed, but over time, the needs of learners have changed. as a result, it has become essential for elts to reflect upon their teaching pedagogies to cater to the needs of learners and learning context. in the mailto:munsif.jatoi@bhu.edu.pk faiza khadim (et al.), teaching oral communication skills to healthcare personnel using communicative language teaching technique (pp. 90-98) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 91 nursing profession, the basic aim is to provide care to patients. in the process, language plays a pivotal role in both understanding and providing nursing care to patients. however, previous studies have not dealt with training nurses received regarding the language in which they are communicating with their patients, or how this language is central to their practices; or how it could assist or deter them in their work [2]. despite the availability of a wide variety of communication methods which could be used to impart education in nursing programs, it has been impossible so far, to determine which of these techniques should be considered the best to improve communication skills of nurses. the communication skills-based courses are included in every discipline including health care. according to [2], “spoken and written communication is a vital aspect of nursing activity. the demand for nurses to communicate effectively in both speech and writing has become more important as a wide audience of patients, purchasers, professional bodies and the law demand satisfactory”. considering the significance of communication skills, this study aims at exploring if the communicative language teaching technique affects the oral english communication skills of nursing students. the purpose of communicative language teaching technique is to help evolve what hymes called “competitive competence” [3]. it can be defined as the extent to which a speaker needs to be familiar with any given topic to be able to speak competently in a given speech community. in [4], it is asserted that communicative language teaching follows the idea that language teaching syllabi should include not only the aspects of language which must be taught but should also shift the paradigm by focusing on exactly how to teach. the strategies in clt teaching technique include real-life communicative situations, where the ability to achieve a task is more important than language accuracy. thus, more focus will be placed on their ability to communicate than on any particular language forms. it implies clt aims to improve students’ oral communication skills of learners according to [6], various communicative activities can be employed to teach oral communication skills. these include techniques such as role-play, language games, and scrambled sentences. in [7], it is stated that several activities are commonly used in clt include interviews, games, role-playing, information gap, surveys, games, pair work and language exchanges. the statement was supported by [8], who stated that several games, for example, role-plays in different settings have been designed specifically with clt classes in mind. in [10], it is further added that these practices should be based on real-life situations that entail communication. this paper is organized as: section ii discusses literature review, section iii provides research questions for this work, section iv provides methodology adopted, section v gives an account for data collection protocol and finally section vi presents the results and discussion. finally, the conclusion from this research work is produced. 2. literature review according to [11], “communication skills can be taught in courses, are learnt, but are easily forgotten if not maintained by practice”. while it is considered most advisable to learn communication skills during clinical placements at medical school, no previous study has investigated has specifically addressed this question. it has been emphasized by several studies that teaching method should be experiential, as the instructional method of teaching failing to provide the desired results. in [12], by simulations and role-plays, students can become more confident and competent in both academic and professional lives, since they receive the theory and practice at the same time. these activities create multiple situations where language learners may use target language efficiently faiza khadim (et al.), teaching oral communication skills to healthcare personnel using communicative language teaching technique (pp. 90-98) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 92 and they would have the chance to express their opinion explicitly without being judged allow them to speak in publicly [9]. another experimental study was conducted by [13] to compare the impact of conventional and cooperative teaching techniques on the communication skills of nursing students when they were interacting with their patients. for that, two groups were randomly selected and nursing courses were taught with different methodologies. results indicated that cooperative learning was a very effective tool in helping to better and enhance the communication skills of students, allowing them to hone interactive skills. according to [14], every student has their own style of learning that helps them to mediate their oral communication skills, and ensure that their communication can have the maximum possible impact, for this, however, teachers should not only be using the usual large-group pedagogic teaching but should also focus on ensuring that their style of teaching is compatible with the students’ learning styles. this will ensure that a large number of students can learn how to communicate properly. for that reason, excessive attention must be paid to the educational requirements of the students at hand. since nursing students are expected to work in various multicultural as well as social scenarios, it is of utmost importance that they understand not only their cultural context but also that of the patients’ they will be tending to. in the nursing and midwifery council document, the emphasize is given to the significance of communication in its code of conduct, and asserts “nurses must meet people’s language and communication needs and share with people in such a way they can understand the information they want or need to know about their health”. this would likewise help them to make more informed decisions about the healthcare that they wish to receive as well as the form of treatment they would like to take [15]. consequently, nurses are required to have a command over communication skills. research questions 1. does the communicative language teaching approach have an effect on the students’ oral english communication skills? 2. does the use of role-play technique have any significant difference in pre and post performance of nursing students’ performance? 2. methodology the study employed quasiexperimental design. sample size was calculated by using the online openepi calculator by taking pre-mean score=10.77±3.1, post mean score=18.04±2.08, power of test=80% and 95% ci as documented by a study assessing the effect that targeted instruction can have on the communication skills of final year students in a medical college in india. openepi stands for open source epidemiologic statistics for public health and is used for statistical applications i.e. descriptive and analytical studies. the least sample found was 6. however, 44 participants were taken as the sample size of the study. in this study, purposive sampling technique was employed. purposive sampling is defined as “the process of selecting a sample that is believed to be representative of a given population”. therefore, the teacherresearcher identified the following criteria for selecting sample technique: (a) students enrolled in the first year of their academic programme, (b) students who do not have any prior english language training at college. the students included in the study were enrolled at a nursing institute. they were also enrolled in the english classes being conducted. one intact class, with 44 students, was selected. 14 (30%) girls and 30 (70%) boys participated in the study. the first language of the students varied between urdu, punjabi, sindhi, hindi, gujarati, and chitrali. the average age of participants was 18 years, although the group contained individuals faiza khadim (et al.), teaching oral communication skills to healthcare personnel using communicative language teaching technique (pp. 90-98) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 93 between 18 to 22 years. it was observed that the participants’ english proficiency in speaking, listening, reading, writing and knowledge of grammar was between beginner and low intermediate. for intervention, prescribed syllabus for students was used from the nursing curriculum, and the study was a continuum of the co-curricular activities. in the pre-test and post-test, the students were given role-play situations and they were tested for grammar, lexical choice, fluency, comprehension, range, and interactive comprehension. roleplays are an integral part of the communicative language teaching technique because this strategy provides students with the opportunity to implement their learning in various social situations and within different societal roles [17]. on the other hand, it is stated in various works that role-play activities involving role-plays are designed to help students understand a wide array of situations, and imagine how they could act appropriately on each one of them. in [18], it is stated that the role-play can enhance the speaking abilities of students through creating real life situations in a conversation form. similarly, [19] identified role-play as a teaching practice that motivates students’ engagement in the language learning process. for tool validity, peer debriefing, internal and external validity was used. two experts, i.e. one nursing manager and one english as a second language (esl) teacher, were involved to validate the rubric. expert insured the face, construct and content validity.fig.1 shows the methodology flow for this research work. 3. data collection protocol firstly, a pre-test was designed to assess the data about the students’ baseline status of their proficiency in english communication. in the pretest, students were given situations in which they were asked to assume the given role and act out an adopted role. students were assessed through rubrics. after evaluation of pre-test, students were taught different domains of communicationbased on their curriculum through different teaching techniques. after teaching, another similar post-test was administered and scores of the participants were recorded to evaluate the effectiveness of the intervention. fig. 1: flowchart of methodology all participants were asked to complete the pre-test in class under the supervision of an esl teacher. students were instructed about the nature of the speaking test and the amount of time they would be given. the participants were divided into a group of 4. they were randomly assigned situations for role-playing. role-play situations were designed to test the participants’ threshold point. an analytical rubric was used to assess students score based on their performance and to minimize the chances of subjectivity, an elt expert was called upon for evaluation. the main teacher acted as a secondary research approach study design sampling technique tools and analysis start end faiza khadim (et al.), teaching oral communication skills to healthcare personnel using communicative language teaching technique (pp. 90-98) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 94 assessor. after discussion when both teachers agreed on common ground, scores of participants were recorded and study plan for a communicative language teaching approach was formulated. the full score for the test was 20. in the intervention, eight classes were planned and each class lasted 120 minutes. students were taught using the following activities: short talk, warm-up activities, roleplay (pair & groups), interviews, discussion, authentic text, poster presentation, debate, and impromptu speeches. these activities consist of group and pair work and were selected from [20]. in the first speaking session, students were grouped in pairs and each of them received a blank identity card. then, they interviewed each other to fill in the blanks on the identity card. each student introduced his partner to the whole class using the identity card as an aid. each student was required to ask those things from his partner, which he/she thinks are significant or exciting. in the second speaking session, students were divided into groups. one student in a small group was given a series of pictures that have a story sequence. he/she showed the pictures of the story to the class and asked them to predict the rest of the narrative. then, at the end of the sessions, each group was asked to narrate the story to the whole class. in the third speaking session, students were divided into groups again. in each group, one student (who either volunteers or is drawn by lot) was interviewed by all the other group members. in the fourth speaking session, students were divided into groups and they all were given role-play situations and were asked to express their feelings. for example, “you have just learned that a colleague’s father has died”. in this session, students were instructed to structure their roles. for that, they were given 30 minutes for preparation. at the fifth speaking session, the teacher distributed handouts that had a copy of different column from a recent newspaper. they were instructed to read it and make a poster. afterwards, they were asked to present their posters to the entire class. in the sixth speaking session, the class was divided into two groups. one of the groups was told to support the topic while the other was told to speak against it. besides, the students were instructed to use expressions of agreement, disagreement, partial agreement, and interruption. for instance, some people think teachers should ask disruptive students to leave the class. in your opinion, what’s the best way to deal with such students? in this way, a kind of a debate competition takes place in the class where each student from each group got a chance to speak once before the entire class to refute his/her point/argument. in the seventh speaking session, the teacher involved students in discussion activities. for example, the teacher outlined the task in which students were given a list of 14 occupations. they were instructed to rank them according to two criteria. firstly, they had to arrange the jobs in the order these jobs are paid in our society. after completing this, they were asked to propose a list of occupations based on how important they think each job should be. students were instructed to work with their neighbor and then discuss it with others. in the eighth and the last session, students were asked to give impromptu speeches. they were randomly assigned different topics and allotted fifteen minutes for brainstorming. the session aimed to make students speak in a complete spontaneity without researching and organizing their ideas. in all eight interactive sessions, the teachers guided class and from time to time observed the students’ performance. she acted as a facilitator of the activities, but she did not herself interact with the students. most of the time, the teacher was a co-communicator and establishes the situation that prompt communication between and among the students. after the teaching of sixteen hours, the same pre-test was administered and the scores of the students faiza khadim (et al.), teaching oral communication skills to healthcare personnel using communicative language teaching technique (pp. 90-98) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 95 were recorded for further analysis. the flowchart for data collection protocol is provided below in fig. 02: fig. 2: flowchart of data collection 4. results & discussion the data was statistically analyzed by using spss version 19. for each participant, marks obtained before and after the test were summarized. standard statistical measures such as mean, mode, median, standard deviation was computed of both tests. then, wilcoxon signed rank test analysis was applied to assess and compare scores before and after the test. table i: mean, standard deviation, minimum and maximum of pre and post test n me an std. devi ation mini mum maxi mum ra ng e p re te st 4 3 10. 230 2 3.36 845 6.60 18.8 0 12. 20 table 1 represents the summary statistics of pre-test. mean of sum scores of pre-tests among student nurses was 10.23 with a standard deviation of 3.36. the minimum score was 6.60 and the maximum was 18.80 with a range of 12.20. table ii: mean, standard deviation, minimum and maximum of post test n me an std. devi ation mini mum maxi mum ra ng e p re te st 4 3 12. 776 7 3.58 003 6.60 20.0 0 13. 4 table 2 represents the summary statistics of post test. mean of sum scores of post test among student nurses was 12.77 with a standard deviation of 3.58. the minimum score was 6.6 and the maximum was 20.0 with a range of 13.4. it can be noted that students performed better in post-test as compared to pretest. the overall statistics showed there was a statistically significant difference in the oral communication skills of nursing students from pre-test to post-test. start pre test interventions speaking sessions post test end faiza khadim (et al.), teaching oral communication skills to healthcare personnel using communicative language teaching technique (pp. 90-98) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 96 table iii: rank table n mean rank sum of ranks post-pre negative ranks 1a 2.00 2.00 positive ranks 38b 20.47 778.00 ties 4c total 43 a. post< pre b. post> pre c. post=pre the ranks table provides insights into the comparison of participants' before (pre) and after (post) intervention. wilcoxon test was applied to find out whether there was a difference between pre-test and post-test performance. hence, mean is provided to make the analysis statistically valid. the post and pre prefix defines the results before and after intervention rspectively. as seen in table 4, the analysis indicated that the communicative language teaching approach had a significant effect on the learners’ performance from a pre to post-test. the wilcoxon sign rank test indicated that the scores obtained after the test were considerably higher than those obtained before the test. therefore, it can confidently conclude that the clt approach can yield statistically significant and improved result in nursing students’ oral communication skills with a z value of -5.422 that indicates the high statistical significance of the result. table iv: test statistics the results of the experiment found clear support that the communicative language teaching approach proved to be effective in improving oral communication skills of nursing students. from the above findings, it is clear that students tend to learn more in those activities where a “real communicative context is the focus, where real information is exchanged, and where the language used is not predictable”. in [5], it is claimed that communicative language teaching approach could be used to reduce the anxiety level of students in an efl classroom. it can also be applied in the current study because the performance of students was increased after implementing clt activities. it may, therefore, be assumed that due to interactions and real communicative tasks i.e. role-play, students’ anxiety level was decreased and it would, in turn, help them to improve their performance. since communicative activities not only provide opportunities for the students to perform at their optimum level but also, they get a chance to learn in more realistic and real-life situations. for that purpose, in this study researcher has used role-plays as a tool for pre-test and post-test and the mean score of post-tests depict a very comprehensive illustration of increased students’ performance. that further strengthens that role-plays were effective in assessing and enhancing the students' performance. in [21], it is examined how students; speaking skills can be improved through classroom interaction. the results were affirmative as it was found that students’ communication inside the classroom enhanced their speaking ability. she further suggested that devoting few hours as post-pre z -5.432b asymp. sig. (2-tailed) .000 a. wilcoxon signed ranks test b. based on negative ranks. faiza khadim (et al.), teaching oral communication skills to healthcare personnel using communicative language teaching technique (pp. 90-98) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 97 classroom interaction would motivate students to have profound conversations and ultimately their communicative skills would polish. in addition to this, in the current study through the results of post-test, it can also be interpreted that students became more motivated after the intervention. in [22], it is explored the correlation between clt related activities and the impact it had on the motivational levels of students aiming to learn english. the results revealed that language learners considered clt activities to be motivating because when they were involved in communicative activities it helped them to improve their fluency, pronunciation, and performance. in the same vein, in the current study students improved their grammar, lexical choice, fluency, comprehension, range, and interactive comprehension. while implementing clt, the teacher should consider that correction of mistake should not be done spontaneously rather it can be done during discussion or feedback session. in this way, students’ performance would not be affected. in [23], it is investigated efl learners’ opinions to predict their attitude towards implanting communicative activities in the classroom. he found a very high level of conformity regarding implementing clt among students. there is the effectiveness of using clt in learning speaking. in his study, the means of both the pre-test, as well as the post-test scores indicate that the post-test mean is considerably higher than the pre-test mean. the findings of the study help us to understand that students’ speaking score improved after they were taught through clt methods. it is worth noting that the results of the present study corroborate the results of previous studies. a similar results’ pattern was obtained after analysis and it can be claimed the clt method of teaching is an effective method when it comes to improving the oral communication of nursing students. 5. conclusion the overall findings of the study indicate that there is a statistically significant difference in nursing students’ performance before and after the test. from the results, it is also concluded that the use of role-play as communicative language teaching (clt) techniques was found effective in improving oral communication skills of nursing students. the findings of this study have a number of practical implications to ensure successful implication of clt in pakistani esl context: (a) the teacher should create or adapt activities that are interesting and meaningful to encourage learners to communicate as smoothly as possible. for example, activities that require active participation i.e. roleplays or discussion activities should be more integrated. it can reduce anxiety in learning and would help to increase participation and create a cooperative learning environment. (b) the teachers should also be aware that they are teaching mixed ability students where there is a combination of beginners, intermediate and advanced students. in order to involve all students, tasks should be simplified and comprehensive. (c) the teachers should ensure that students interact a great deal with one another. they do this in various configurations: pairs, triads, small groups and whole groups. (d) the teachers should understand their role as facilitator and co-communicator. in addition, future researchers could explore other dimensions of the same study in several ways, for example, a controlled group can also be taken or comparative analysis may be done. also, this research can be replicated qualitatively for an in-depth understanding. references [1] khan i.u., ayaz m., saif n., “comparative analysis of the effectiveness of communicative language teaching with grammar translation method of teaching functional english at secondary level in khyber pakhtunkhwa,” sci. int., vol. 28(3), pp. 2751-2755, may 2016. [2] crawford, paul, brian brown, and peter nolan, “communicating care: the language of nursing,” nelson thornes, 1998. faiza khadim (et al.), teaching oral communication skills to healthcare personnel using communicative language teaching technique (pp. 90-98) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 98 [3] richards, jack c., and theodore s. rodgers, “approaches and methods in language teaching,” cambridge university press, 2014. [4] harmer, jeremy, “the practice of english language teaching,” longman, 2001. [5] wu, kun-huei, “the relationship between language learners' anxiety and learning strategy in the clt classrooms,” international education studies vol. 3 (1), pp. 174-191, 2010. [6] applebaum, bruce, “communicative language teaching: theory, practice, and personal experience,” the jurnal mandiri vol. 9(4), april 2007. [7] yu, liming, “communicative language teaching in china: progress and resistance,” tesol quarterly vol.35 (1), pp. 194-198, 2001. [8] richards, jack c., “communicative language teaching today,” singapore: seameo regional language centre, 2005. [9] hiep, pham hoa, “communicative language teaching: unity within diversity,” elt journal vol. 61(3), pp. 193-201, 2007. [10] alwazir, basma, and nadia shukri, “the use of clt in the arab context: a critical perspective,” international journal of english language education, vol. 5(1), pp.15-32, 2016 [11]aspegren, knut, “beme guide no. 2: teaching and learning communication skills in medicine-a review with quality grading of articles,” medical teacher vol.21 (6), pp.563-570, 1999. [12] kameg, kirstyn, et al. “the impact of high fidelity human simulation on selfefficacy of communication skills,” issues in mental health nursing vol. 31(5), pp. 315-323, 2010. [13] baghcheghi, nayereh, hamid reza koohestani, and koresh rezaei, “a comparison of the cooperative learning and traditional learning methods in theory classes on nursing students' communication skill with patients at clinical settings,” nurse education today vol. 31 (8), pp.877-882, 2011. [14] davies, h. t., and crombie, i.k., “interpreting health outcomes,” journal of evaluation in clinical practice vol. 3(3), pp. 187-199, 1997. [15] donnelly, elaine, and lindsey neville, “communication and interpersonal skills,” reflect press, 2008. [16] wright, ros, “effective communication skills for the “caring” nurse,” the great teachers: tertiary place, 2012. [17] larsen-freeman, diane, “techniques and principles in language teaching,” oxford university, 2000. [18] huff, cliff, “action research on using role play activity in an adult esl level one class,”2012. [19] tompkins, p. k. “role playing/simulation,” the internet tesl journal vol.4 (8), pp. 143-150, 1998. [20] klippel, f., john h. k., and penny ur, “keep talking: communicative fluency activities for language teaching. cambridge university press, 1984. [21] azadi, somayeh, mohammad aliakbari, and akbar azizifar, “the role of classroom interaction on improvement of speaking among iranian efl learners,” international journal of language learning and applied linguistics world vol.8 (1), pp. 126-135, 2015. [22] ochoa, césar, et al. “the effect of communicative activities on efl learners' motivation: a case of students in the amazon region of ecuador,” colombian applied linguistics journal vol.18 (2), pp. 39-48, 2016. [23] wajid, mohammad abdul, and mohammad saleem, “learner conformity to communicative language teaching approach in efl contexts: a case study in saudi arabia,” international journal of language and linguistics vol.4, pp. 240-249, 2017. vol. 3, no. 2 | july december 2020 sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 24 design of low-cost synchronous reluctance motor with a surrogate-assisted optimization technique syed abid ali shah bukhari1*, imtiaz ali leghari1, junaid iqbal bhatti1, saleem raza1, mohsin ali koondhar1, irfan ali channa2, muhammad usman keerio1 abstract: this paper presents the performance of centrifugal pump coupled with synchronous reluctance motor of 24kw. the 4-pole 36 slots induction motor stator has been used for the prototype. the reduction of torque ripple and power losses is the main aim of research. different arrangement of rotor flux barrier shapes has been tested through finite element analysis method. the rotor optimization is done by varying different parameters are used such as, barrier edge angle, width of flux carriers, flux barriers and shaft diameter. in order to improve the motor performance, the method of particle swarm optimization has been used by generating samples with surrogate assisted optimization technique. distinct flux barrier shapes and designs have been checked through simulation. for the prototype development, final v-shaped best model is chosen. the proposed rotor shows the excellent performance in terms of reduced torque ripple (27%) and improved average torque (154nm) in experimental results. the suggested design also has good thermal and mechanical performances with the capability to use in various industrial applications. keywords: torque ripple, particle swarm optimization, surrogate based technique, flux barrier, machine design, synchronous reluctance motor, direct drive. 1. introduction the construction of transverse-laminated rotor structure of synchronous reluctance motor (synrm) is attracting the attention by the different users, because of its simple construction, cost, robustness and manufacturing process [1],[2]. typically, a pumping system is mostly used to couple an induction motor of 1500 rpm with a centrifugal pump but, this system has a lot of disadvantages such as heavy and bulky motor drive system with low energy efficient. in this 1 quaid-e-awam university of engineering, science and technology, pakistan 2 department of automation, beijing university of chemical technology, beijing, china corresponding author: abidshah@quest.edu.pk regard, for high-torque applications, permanent magnet synchronous machines (pmsm) are dominated, but the most important issue is the recycling of these rareearth metal permanent magnets. additionally, the cost of magnetic material collectively with demand and supply chain issues is actually preventing these machines from assuming its rightful place as a motor of choice near future. so as the price rate of rare-earth magnets is growing, at the same time their market stability is declining [3]. thus, a universal satisfactory solution has not been adopted for mailto:abidshah@quest.edu.pk syed abid ali shah (et al.) design of low-cost synchronous reluctance motor with a surrogate-assisted optimization technique (pp. 24 – 39) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 25 application of closed coupled centrifugal pumps. after an improvement in electrical drives in 20th century due to enhanced efficiency and fast dynamic response of the drives, the reluctance motors represents a much possible alternatives [4],[5]. the reluctance motors have a unique rotor structure which is arranged from laminated steel and do not use permanent magnet. there is salient rotor and works on the basis of reluctance torque. there are two types of reluctance machine the number one is switched reluctance motor (srm) and second is synchronous reluctance motor (synrm). if the stator is of round configuration and fed with ac supply with different phases the machine is called synchronous reluctance machines. if the stator has salient poles structure, the machine is called switched reluctance machine. the srm has high torque ripple and separate dc input source is required to excite the winding. whereas synrm utilize sinsoidally distributed windings as in induction or synchronous machines and requires easily available universal sinusoidal supply, so that’s why author has decided to take synrm for the research. many industrial applications require low torque ripple, therefore lots of studies have been conducted and to enhance the performance of the machine, like in [6],[7],[8],[9], the torque ripple is investigated and multiple solutions are tested. further to enhance the torque density of the machine, the rotor design is investigated in [10],[3],[11] in which the saliency ratio is examined which denotes the ratio between the d-axis and qaxis. for synrm rotor, the type of axially laminated anisotropy (ala) is mostly used in a high-speed operation as proved in many research investigations [12-15]. due to rigid structure and improved saliency ratio [16-18]. however, because of very thicker laminations it produces unwanted flux oscillations with very high iron losses. therefore, tla type rotor is most preferable because of simple construction and low losses [19-22]. hence, due to above advantages of synrm simulation model design it has been decided to use tla type rotor. it is aimed to select the number and shape of flux barriers to achieve the low power losses along with low torque ripples. the paper is distributed in three different sections. the section i describes the background of research. (a) (b) syed abid ali shah (et al.) design of low-cost synchronous reluctance motor with a surrogate-assisted optimization technique (pp. 24 – 39) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 26 (c) fig 1: four flux barrier rotor’s different designs of synrm (a) 4 v-shaped flux barrier rotor (b) 4 square shaped rotor (c) 4 straight flux barriers with slight angle at the edges. the detailed rotor design with three and four flux barriers and its advantages have been described through simulation in section ii. also, in order to minimize torque ripple and to enhance efficiency, the analysis on flux barriers and flux carriers carried out by varying the width, and shaft diameter while using infolytica magnet software. in section iii the development of rotor from manufacturing point of view and its process is mentioned. in order to validate the proposed rotor model, a test bench is set up by manufacturing the designed rotor and the prototype development steps are conducted with the experimental results and discussion with no-load test, low-slip test and over speed test operation and experimental results of the proposed machine have been described in section iv. in section v, the brief analysis of results has been presented. finally, section vi describes the research methodologies along with application and future trends. (a) (b) syed abid ali shah (et al.) design of low-cost synchronous reluctance motor with a surrogate-assisted optimization technique (pp. 24 – 39) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 27 (c) (d) fig 2: three and four flux barrier rotor designs for synrm (a) 4 square shaped flux barrier rotor (b) 3 vshaped rotor (c) 4 square shaped flux barriers with slight angle at the end and 3 square shaped flux barriers. 2. working prniciple of synrm in synrm, to achieve the maximum output, the saliency ratio (ld-lq) should be maximized. in this rotor design 0.6 to 0.7 percent saliency ratio has been used. however, the torque is generated through reluctance variation at different rotor positions. the motor torque is directly proportional to the transformation of the magnetizing inductance (d-q axis) which impacts the coordinate system of rotor reference frame. in machine design, the main challenge is to maintain thermal constraints because of stator and rotor windings [23]. therefore, it is essentially needed to reduce the involvement of winding material and magnetic mass. in [24] a low speed domestic application with direct-drive synrm having six rotor geometries has been presented. most of the synrm employs advanced transversally laminated rotor structure. the rotor cage design is taken out as the machine can be easily started synchronously through inverter control system. therefore d-q equations of synrm [25] are established as follows. 𝑉𝑑𝑠 = 𝑟𝑠 𝑖𝑑𝑠┿ 𝑑 𝑑𝑡 𝐿𝑑𝑠 𝑖𝑑𝑠 – 𝜔𝑟 𝐿𝑑𝑠 𝑖𝑞𝑠 (1) 𝑉𝑞𝑠 = 𝑟𝑠 𝑖𝑞𝑠┿ 𝑑 𝑑𝑡 𝐿𝑞𝑠 𝑖𝑞𝑠 – 𝜔𝑟 𝐿𝑑𝑠 𝑖𝑑𝑠(2) the lds and lqs represents the quadrature and direct axis inductances. the (ωr) is speed, whereas each phase of stator resistance is denoted by (𝑟𝑠 ). the electromagnetic torque in terms of d-q variables, is identical to that of a synrm, namely 𝑇𝑒 = 3 2 𝑃 2 (𝐿𝑑𝑠– 𝐿𝑞𝑠) 𝑖𝑑𝑠 𝑖𝑞𝑠 (3) whereas number of poles are denoted by p. in order to model the asynchronous machine, above equations are used. 3. design and simulation of synrm in order to choose the best rotor design, seven different geometries of three and four flux barrier have been examined and finite element analysis carried out. all the test was conducted at 1500rpm as fig. 1 shows the different flux barrier designs of the rotor. (a) syed abid ali shah (et al.) design of low-cost synchronous reluctance motor with a surrogate-assisted optimization technique (pp. 24 – 39) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 28 shows the four flux barriers with v-shaped designs in this design the flux barrier edge angle is kept 49 degree and the torque ripple is 27% which is good but machine efficiency is very low and the total average torque produces by the machine is 134nm and one additional factor which is the flux density is higher up to 2.29. in design (b) the more angle is provided to sharp edges but the the efficiency reduces to 37% and torque ripple is still higher to 70% and overall average torque is also reducing to 93nm with flux density 2.2t. in design 132nm torque is produced with 2.38t flux density and the torque ripple is 42%. in fig. 2 (a) circular shape with four flux barrier design are tested which gives the efficiency 47% with 118nm torque and 2.18t whereas, torque ripple is slightly higher 44%. in (b) three v-shaped flux barrier design are tested which produce the highest torque 158nm with 70% and low torque ripple 30% but flux design is higher 2.7t. the design (c) gives 134nm torque and 2.5t density and torque ripple is higher upto 46% with 63% efficiency. in (d) three square shaped flux barrier are used which produces 134nm torque and 47% torque ripple with 2.17t flux density. 4. development of synchronous reluctance motor keeping above data analysis in terms of torque, efficiency, torque ripple and flux density in section iii, the author decide to take three v-shaped design as a main investigation point due to its higher high efficiency and torque production. further design variables flux barrier and carrier width with edges and shaft diameter are modified accordingly. consequently, a 3-flux barrier’s rotor of 24kw synrm with motor has been simulated with the specifications shown in table, i and ii. fig 3: design rotor dimensions of synrm table i: 24kw synrm specifications. parameter units value symbol number of phases 3 m total flux barriers 3 speed rpm 1500 nn number of turns turns 12 np number of stator poles 4 ns frequency hz 50 f rated current amps 26 i angle of edges o 4 deg rated power kw 24 p saliency ratio 0.7 phase voltage v 380 vdc stator diameter mm 310 ds air-gap mm 1 g machine length mm 200 l average torque nm 154 tav diameter mm 188 dr shaft diameter mm 50 dsh table ii. synrm rotor design specifications item value item value rotor materi al m35050amp carrier width 12.06, 9.92,9.97,10 .21 barrie r width 9.02, 8.97, 8.81 syed abid ali shah (et al.) design of low-cost synchronous reluctance motor with a surrogate-assisted optimization technique (pp. 24 – 39) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 29 overal l carrier width 42.17 overa ll barrie r width 26.822 rotor od 188 mm flux barrie r edge angle 3 and 4 deg length of first barrier (starting at outer diameter) lower 35.9mm upper 36mm length of second barrier lower 36mm upper 36mm length of third flux barrier lower 35.63mm upper 35.91m m note: all the dimensions are depicted in rotor’s half or 4th quadrant in fig. 3. at first four and five barriers with square shaped ware simulated. however, their performance was not reasonable and machine was generating 2.7t magnetic flux density and the produced torque was also low in between (100 to 120nm). then configurations of 3 flux barrier were simulated with v-shaped flux barrier design has been proposed, as depicted in fig. 4(a) and two-dimensional mesh view is shown in fig. 4(b). the 2.1 tesla of flux density, current waveform and produced torque is shown in fig. 5 (a to c) respectively. (a) (b) fig 4: (a) model of two dimensional synrm (b) triangular view of meshes at 500 milliseconds transient simulation with velocity-driven settings carried out, thus machine can produce effective starting torque 180 nm and 154.30nm average torque with 90% efficiency. the portion of the shaft kept hollow to avoid additional magnetic losses therefore its losses are very negligible, so that’s why has author has not considered in this work. the copper, hysteresis and eddy current losses are 2.358watts and the stator hysteresis and eddy current losses are 379watts, the 1000/65 newcore nonlinear lamination material selected for the stator and for rotor lamination m350-50a material used in the machine. syed abid ali shah (et al.) design of low-cost synchronous reluctance motor with a surrogate-assisted optimization technique (pp. 24 – 39) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 30 (b) (a) (c) fig. 5 (a) 2.1 (tesla) flux density (b) flux linkage (c) generated torque of the synrm syed abid ali shah (et al.) design of low-cost synchronous reluctance motor with a surrogate-assisted optimization technique (pp. 24 – 39) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 31 fig 6: the 4 pole 36 slots double layer stator 5. experimental validation subsequently the optimization of rotor design scheme the machine performance was examined and the 3-flux barrier rotor design was chosen for further refinement and surrogate based optimization technique was applied with four main variables of rotor design which are flux barrier width, flux carrier width, shaft diameter and barrier edge angle. total 20 latin hypercube samples are generated to check the toraue, efficiency, torque ripples and magnetic flux density. and finally, best design is selected for the prototype development. fig 7: prototype development stages of the proposed rotor (a) early manufacturing from the factory (b) flux barrier filling with magic and pvc (c) assembled rotor with shaft (d) final assembled rotor after machining syed abid ali shah (et al.) design of low-cost synchronous reluctance motor with a surrogate-assisted optimization technique (pp. 24 – 39) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 32 in order to improve the mechanical integrity of the rotor manufacturing process, the polyvinylchloride material was inserted inside of the flux barrier and it took almost 2 days to dry the rotor. the complete rotor manufacturing stages from manufacturing in the factory to assembled rotor in the machining process are shown in fig. 7. the stator for the proposed motor used is identical of standard cummins bci-184f machine is shown in fig. 8, whereas the complete specifications are described in [26, 27]. there are short-pitched 2/3 winding arrangement with double layer star connection. each slot area is 144mm2 for individual layer. the experimental test rig of the whole was built and tested as depicted in fig. 8. fig 8: the standard stator from a cummins bci-184f machine a-no-load test an experimental set-up was conducted in order to measure the rated voltage, current, power and other parameters at no-load and is shown is fig. 9. the no load speed test is conducted at 13.3⁰c ambient temperature by coupling the shaft of proposed machine with 55kw permanent magnet synchronous machine. the simulation results achieved through the fem analysis are validated by experimental measurements on the test bench. the designed synrm was tested under noload condition, at fifteen different driven speed and ten different frequencies. the frequency varied at steps: 5, 10, 15, 20, 25, 30, 33, 35, 38, 40, 42, 45 and 50. thus the machine speed has been changing according to synchronous speed: 150, 299, 452, 600, 752, 900, 995, 1052, 1140, 1200, 1260, 1314, 1350, 1433, 1500 rpm. table vii. no-load experimental data of speed, current, voltage, power, power factor, harmonics and vibration from 0-50hz frequency. fig 9: experimental test rig a. the synrm b. siemens drive c. 55kw load motor d. abb drive e. temperature meter f. oscilloscope tektronix tds 2024b g. torque meter jn-338 h. fluke power meter i. mutimeter j. speed meter k. torque transducer l. siemens circuit breaker cdm10-100/3300 delixi m. motor side coupling n. n. load side coupling 43.8, 45, 47.8, 50 hz frequency. table iii presents the rms value of current and voltage with power, power factor, total harmonics distortion and vibration reading at various speed. table iv shows the temperature readings at for 150 to 1500 rpm driven speed respectively and fig. 10. depicts the temperature graph at 5 to 50hz frequency. as it can be noted that the from no-load test results the number of harmonics and vibration is decreasing as the machine is getting higher syed abid ali shah (et al.) design of low-cost synchronous reluctance motor with a surrogate-assisted optimization technique (pp. 24 – 39) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 33 speed mainly due to fact that as the machine’s performance becomes more stable. the reduction of harmonics and vibration content is therefore and important achievement in the results. table iii. no-load test temperature experimental data of speed, current, voltage, power, power factor and harmonics from 0-50hz frequency. b-low-slip test in order to verify the analysis in the paper, the low slip test is performed. in the low slip test different performance of synchronous reluctance motor carried out, the speed is varied from 150 to 1500rpm by siemens vfd and the load motor 55kw is rotated anti clockwise at different speed and torque settings and all the parameters are noted such as current, voltage, power, power factor and harmonics. the test machine is derived by siemens-micromaster-440 drive and the 55kw coupled machine is derived by abb acs800 drive. the temperature readings along with current, voltage, power, power factor and harmonics are shown in table iv and v, whereas the harmonics reading and parameter setting of load drive motor is shown in table vi. hz rpm i v kw p.f harmonics vibration m/s2 5 150 17.8 155 0.28 0.08 254 102.1 10 299 18.3 163.5 0.29 0.09 141.8 99.9 15 452 18.2 172.9 0.36 0.10 165% 98 20 600 18 182 0.34 0.09 116% 99.6 25 752 18 190 0.36 0.10 16.7/0.4/5.3 98.5 30 900 18.1 196.2 0.36 0.10 9.2/6.7/0.3 100 33 995 19.7 199 0.38 0.11 13.6/2.4/14.7 97.2 35 1052 18.2 202 0.40 0.11 8.5/7.5/0.4 97.7 38 1140 18.4 208 0.42 0.11 14.5/12.4/7.1 97.9 40 1200 18.4 213 0.45 0.12 14.3/11.2/ 96 42 1260 18.8 217.4 0.52 0.13 8.26% 91.5 43.80 1314 21.7 221 0.53 0.13 8.3/13.7 91 45 1350 18.4 229 0.52 0.13 6.7/4./0.8 92 47.8 1433 18 236 0.55 .13 8.3/13.7 93 50 1500 18.4 249 0.56 0.14 6.4/5.1/0.6 93 syed abid ali shah (et al.) design of low-cost synchronous reluctance motor with a surrogate-assisted optimization technique (pp. 24 – 39) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 34 fig 10: temperature graph as different input frequency and speed table iv. low-slip test temperature readings of the test machine from 0-50 frequency and 0 to 1500rpm rated speed frequency t1 t2 t3 t4 t5 rpm 5hz 29.3 30 31.9 32 27.6 150 17hz 32.3 34.1 37.2 30 31.4 513 25hz 32.3 34 36.6 31.3 31.8 750 not torque applied by abb at 50hz 25hz 32.8 34.5 36.8 33 32.7 750 30hz 32.8 34.2 36.7 33.2 33.2 899 now torque applied on the machine 30hz 32.7 34.1 36.7 33.4 33.6 900 35hz 33 34.5 37.1 33.6 34.1 1050 now torque applied on the machine 35hz 33.5 34.9 37.5 34.3 34.6 1050 40hz 34.1 35.2 37.9 34.8 35.7 1200 now torque applied on the machine 40hz 34.2 35.2 37.9 34.4 35.9 1200 45hz 35.4 36.2 39.5 36.2 36.8 1356 now torque applied on the machine 45hz 36.1 37 40.2 37.1 37.8 1350 50hz 36.6 37.7 41.1 37.6 38.3 1500 syed abid ali shah (et al.) design of low-cost synchronous reluctance motor with a surrogate-assisted optimization technique (pp. 24 – 39) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 35 table v. low-slip test frequency rpm current voltage power p.f 5hz 150 18 139 0.22 0.09 17hz 513 18.2 163 0.36 0.12 25hz 750 17.8 181 41 0.14 now torque applied by abb at 50hz 25hz 750 18 181 0.51 0.16 30hz 899 18 192 0.54 0.17 now torque applied on the machine 30hz 900 18.2 191 0.68/0.76 0.21 35hz 1050 19 312 0.85 0.224 now torque applied on the machine 35hz 1050 18.8 200 0.94 0.25 40hz 1200 18.9 211 1.10 0.26 now torque applied on the machine same all 1200 18.9 211 1.10 0.27 45hz 1356 20.7 227 1.17 0.28 now torque applied on the machine 45hz 1350 20.7 226 1.76 0.37 50hz 1500 23.8 239 2.29 0.41 table vi. harmonics produces by the synrm and parameter settings of load motor. harmonics torque nm abb drive reference settings hz/rpm abb drive current 512% 0.2 0.1hz/ 44.7% 0.42 0.6/-9.8 2.4 0.5 0.6/-9.8 2.9 not torque applied by abb at 50hz 14.5/4.9/0.4 0.8/-11.7/-52% 45/6.3 8.3/3.0/0.5 0.9 0.8/-11.7 45/6.3 now torque applied on the machine 8.5/3.3/0.2 1.4 1/68% 68/10.1 7.5/4.8/0.3 1.7 1.1/-77% 67/11.4 now torque applied on the machine 7.4/4.2/0.2 1.7 1.2/-16rpm/-84% 72/15 12/8.2/2 2.3 1.2/-16rpm/-84% 72/15 now torque applied on the machine 12/8.1/0.3 2.3 1.4/-19/99 86/19 7.2/6.3/0.2 2.9 1.4/19.6 84/11.8 now torque applied on the machine 7.2/6.2/0.3 3.4 1.7/-23.8/117.74t 102.84/12 5.9/6.1/0.3 3.9 1.7/-24.7rpm/-113t 99.74/18 syed abid ali shah (et al.) design of low-cost synchronous reluctance motor with a surrogate-assisted optimization technique (pp. 24 – 39) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 36 c-overspeed test in order to verify the analysis in the paper, the over speed and test is performed. firstly, the machine was speedup to normal speed at 1500rm and then gradually speed was increased while varying the frequency from 51-55hz. it was observed the machine was running good with thermally stable. the experimental results of overspeed test are shown at table vii and viii. table vii. low-slip test experimental data of speed, current, voltage, power, power factor and harmonics from 0-50hz frequency. speed rpm frequency current voltage power p.f harmonics 1530 51hz 1530 18.9 245 0.44 0.15 1560 52hz 1560 22.5 248 0.63 0.124 1590 53hz 1590 17.8 249 0.0.59 0.13 1620 54hz 1620 18.1 251.9 0.65 0.14 1635 54.5hz 1635 17.3 250 0.64 0.14 1650 55hz 1650 17.2 251 0.64 0.15 table viii. over speed test temperature readings of the test machine from 0-50 frequency and 0 to 1500rpm rated speed. speed rpm frequency t1 t2 t3 t4 t5 1530 51hz 29.5 29.6 32.1 23.4 31 1560 52hz 29.8 30 32.4 27.4 31.7 1590 53hz 30.2 30.2 32.7 29.2 31.9 1620 54hz 30.3 30.3 33 31.7 32.2 1635 54.5hz 30.6 30.8 33 31.3 22.6 1650 55hz 30.9 30.8 33.1 32.3 32.8 6. analysis of experiment results the main aim of the experimental validation is to confirm the simulation model at no-load, low slip and over speed test. addition to this, temperature at different speed of each method is determined. in the over speed test as per siemens drive default settings machine is started at 5hz frequency which runs at 150rpm at ambient temperature 16.2 degree centigrade. there are 5 thermocouple temperature sensors have been located at different positions in the test machine. (a) syed abid ali shah (et al.) design of low-cost synchronous reluctance motor with a surrogate-assisted optimization technique (pp. 24 – 39) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 37 (b) (c) (d) fig.11 experimental results (a) the voltage wave form; (b) power and power factor reading; (c) total harmonics distortion; (d) torque wave form at different input frequency and speed the three sensors are used for winding and their location is 120 mechanical degree apart and two sensors are located at stator outer body. the results of over speed test of all the parameters and temperature parameters are shown in table vii and viii respectively. the reading t1, t2 and t3 shows the winding temperature whereas t4 and t5 is the stator outer body temperature. the speed is controlled from the input supply frequency from siemens drive. it can be observed from the data reading that the t3 has the highest reading 33.1⁰c at 15hz frequency with 1650rpm whereas remaining all the temperature reading is below the maximum which reflects that the machine the thermally stable. the graph of bar chart also depicts the temperature reading under various frequency changes as shown in fig 10. the no-load experimental data of speed, current, voltage, power, power factor, harmonics and vibration are shown in table. iii and their corresponding photos of 3-phase current wave form, amperes, voltage and frequency values with total harmonics distortion and generated torque wave form are shown in fig. 11 (a-d). it is observed that initially the machine has high vibration at low speed but as the speed is increased the machine is also stable which is very good in terms of mechanical point of view at can be seen from the data at 50hz frequency and 1500rpm the vibration is 93 m/s2 which is much better than at the time of starting. 7. conclusion this paper has presented the simulation and experimental studies on synchronous reluctance machine with a symmetrical rotor design for centrifugal pumps. a technique based on surrogate with particle swarm optimization has been developed to aid in the machine. distinct shapes of the rotor are analyzed through simulation and modified the flux barrier shape, shaft diameter and angle of edges to reduce the torque ripple and losses of the machine. the experimental results validate the numerical designs for the proposed machine. a permanent magnet material could also be inserted in rotor flux syed abid ali shah (et al.) design of low-cost synchronous reluctance motor with a surrogate-assisted optimization technique (pp. 24 – 39) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 38 barriers to improve flux density. as this would be beneficial for high torque machines. the proposed rotor a symmetrical rotor can improve effective thermal and mechanical performance of the machine and can be beneficial for some applications which are uni-directional in machine operations, as this work is targeted. references [1] s. yammine, c. henaux, m. fadel, s. desharnais, and l. calégari, synchronous reluctance machine flux barrier design based on the flux line patterns in a solid rotor," "in electrical machines (icem), 2014 international conference on, 2014, pp. 297-302. [2] p. s. ghahfarokhi, a. belahcen, a. kallaste, t. vaimann, l. gerokov, and a. rassolkin, "thermal analysis of a synrm using a thermal network and a hybrid model," in 2018 xiii international conference on electrical machines (icem), 2018, pp. 2682-2688. [3] e. howard, m. j. kamper, and s. gerber, "asymmetric flux barrier and skew design optimization of reluctance synchronous machines," ieee transactions on industry applications, vol. 51, pp. 3751-3760, 2015. [4] s. taghavi and p. pillay, "a sizing methodology of the synchronous reluctance motor for traction applications," ieee journal of emerging and selected topics in power electronics, vol. 2, pp. 329-340, 2014. [5] a. boglietti, a. cavagnino, m. pastorelli, and a. vagati, "experimental comparison of induction and synchronous reluctance motors performance," in industry applications conference, 2005. fourtieth ias annual meeting. conference record of the 2005, 2005, pp. 474-479. [6] r.-r. moghaddam, f. magnussen, and c. sadarangani, "novel rotor design optimization of synchronous reluctance machine for low torque ripple," in 2012 xxth international conference on electrical machines, 2012, pp. 720-724. [7] n. bianchi, s. bolognani, d. bon, and m. dai pré, "torque harmonic compensation in a synchronous reluctance motor," ieee transactions on energy conversion, vol. 23, pp. 466-473, 2008. [8] m. sanada, k. hiramoto, s. morimoto, and y. takeda, "torque ripple improvement for synchronous reluctance motor using an asymmetric flux barrier arrangement," ieee transactions on industry applications, vol. 40, pp. 10761082, 2004. [9] m. gamba, g. pellegrino, and a. vagati, "design of non conventional synchronous reluctance machine," 2018. [10] d. staton, t. miller, and s. wood, "maximising the saliency ratio of the synchronous reluctance motor," in iee proceedings b (electric power applications), 1993, pp. 249-259. [11] m. kamper and a. volsdhenk, "effect of rotor dimensions and cross magnetisation on ld and lq inductances of reluctance synchronous machine with cageless flux barrier rotor," iee proceedings-electric power applications, vol. 141, pp. 213220, 1994. [12] j. ikaheimo, j. kolehmainen, t. kansakangas, v. kivela, and r. r. moghaddam, "synchronous high-speed reluctance machine with novel rotor construction," ieee transactions on industrial electronics, vol. 61, pp. 29692975, 2014. [13] m. e. h. zaim, "high-speed solid rotor synchronous reluctance machine design and optimization," ieee transactions on magnetics, vol. 45, pp. 1796-1799, 2009. [14] h. hofmann and s. r. sanders, "highspeed synchronous reluctance machine with minimized rotor losses," ieee transactions on industry applications, vol. 36, pp. 531-539, 2000. [15] y. gessese and a. binder, "axially slitted, high-speed solid-rotor induction motor technology with copper endrings," in electrical machines and systems, 2009. icems 2009. international conference on, 2009, pp. 16. [16] i. boldea, z. fu, and s. nasar, "performance evaluation of axiallylaminated anisotropic (ala) rotor reluctance synchronous motors," ieee transactions on industry applications, vol. 30, pp. 977-985, 1994. [17] d. platt, "reluctance motor with strong rotor anisotropy," in industry applications society annual meeting, 1990., conference record of the 1990 ieee, 1990, pp. 224-229. [18] d. platt, "reluctance motor with strong rotor anisotropy," ieee transactions on industry applications, vol. 28, pp. 652658, 1992. [19] m. j. kamper, f. van der merwe, and s. williamson, "direct finite element design optimisation of the cageless reluctance synchronous machine," ieee syed abid ali shah (et al.) design of low-cost synchronous reluctance motor with a surrogate-assisted optimization technique (pp. 24 – 39) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 39 transactions on energy conversion, vol. 11, pp. 547-555, 1996. [20] s. taghavi and p. pillay, "a mechanically robust rotor with transverse-laminations for a synchronous reluctance machine for traction applications," in energy conversion congress and exposition (ecce), 2014 ieee, 2014, pp. 5131-5137. [21] s. m. taghavi and p. pillay, "a mechanically robust rotor with transverse laminations for a wide-speed-range synchronous reluctance traction motor," ieee transactions on industry applications, vol. 51, pp. 4404-4414, 2015. [22] j. kostko, "polyphase reaction synchronous motors," journal of the american institute of electrical engineers, vol. 42, pp. 1162-1168, 1923. [23] a. a. s. bukhari, s. ali, s. h. shaikh, t. a. soomro, z. lin, and w. cao, "design of a high speed 18/12 switched reluctance motor drive with an asymmetrical bridge converter for electric vehicles," in computing, mathematics and engineering technologies (icomet), 2018 international conference on, 2018, pp. 1-6. [24] m. a. raj and a. kavitha, "effect of rotor geometry on peak and average torque of external rotor synchronous reluctance motor (ex-r synrm) in comparison with switched reluctance motor for low speed direct drive domestic application," ieee trans. ind. appl, vol. 53, 2015. [25] t. matsuo and t. a. lipo, "rotor design optimization of synchronous reluctance machine," ieee transactions on energy conversion, vol. 9, pp. 359-365, 1994. [26] n. yang, w. cao, z. liu, z. tan, y. zhang, s. yu, et al., "novel asymmetrical rotor design for easy assembly and repair of rotor windings in synchronous generators," in magnetics conference (intermag), 2015 ieee, 2015, pp. 1-1. [27] t. yuan, n. yang, w. zhang, w. cao, n. xing, z. tan, et al., "improved synchronous machine rotor design for the easy assembly of excitation coils based on surrogate optimization," energies, vol. 11, p. 1311, 2018. vol. 3, no. 2 | july december 2020 sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 115 dynamic modeling and vector control of ac induction traction motor in china railway mannan hassan1, muhammad suhail shaikh2, h.u.k. jadoon1, rao atif1, muhammad usman sardar3 abstract: in this research paper, control of induction motor drive with high-performance characteristics is developed by using vector control, direct-torque control also with the predictive control model. the coordinate transformation has been introduced and established with the mathematical-models of the induction motor (crh3 high-speed electric multiple units in china railway) in the two-phase rotating reference frame and the two-phase stationary reference frame. along-with the discussion of vector control basic principle, the dynamic mathematicalmodel of the induction motor in the two-phase reference frame is presented. also, the method of the rotor’s field orientation in the two-phase reference frame is presented. based on some metro-traction motor parameters of 2.7kv and 1khz voltages and operating frequency respectively, matlab/simulink simulation result verifies the principle, control performance, and characteristics of different control strategies, which are comparatively analyzed in detail. keywords: induction motor, dynamic modeling, coordinate transformation, vector control, model predictive control, direct torque control 1. introduction: owing to the mathematical and computational advantages, the induction motor, which is also called im. the recent technological development for the application of traction drives has a more important attraction [1]. the corresponding scalar control of the induction motor is relevantly simpler to be implemented, but the variable like torque and flux gives the sluggish response, which is usually inactive, and the control is easily prone to the instable. hence this occurs because of the fifth or higher-order system effects in their stability equations. to visualize it in more depths, let's have an 1school of electrical engineering, southwest jiaotong university, chengdu 610031, china 2institute of electrical engineering, yanshan university, qinhuangdao, 066004, p.r.china 3department of electrical engineering, khwaja fareed university of engineering & information technology rahim yar khan example like the increasing torque affect slip and slip goes increasing with the frequency and magnetic flux decreases. then it is noted that flux is varying, but the corresponding control is not accepted at all. it the flux decreases, then it is compensated by the inactive flux control loop, which is feeding in the additional voltage variable. the vector control method permits higher performance control toque component, rotor speed, or position to be achieved from the induction motor. the rigid construction, lower maintenance cost, higher stability state torque, and more straightforward controller in design, the induction motor drives are going to become more suitable as an alternate mannan (et al) dynamic modeling and vector control of ac induction traction motor in china railway (115 – 125) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 116 application in the traction system. it is sufficiently possible to take if ud we can regulate large (which is of course, assured with large vs) flux of stators. nonetheless for torque control, we will demonstrate that if we want to guarantee that uq should be limited to a small set dtc global convergence. we will establish this outcome in order to establish. assume that separations take place and invoke time-scale separations [13]. there are many control strategies, and the most commonly exploited types are the fieldoriented control (foc) and the direct torque control (dtc) they are commonly used. techniques, as mentioned above, already have been invented in the early ’70s and ’80s, respectively [2]. it is demonstrated like the control of induction motor like dc motor with separately excited schematics made it possible to have a high-performance control of ac motors or drives with their applications. in comparison with the dc-motor like performance, this vector control is also called decoupling, perpendicular, orthogonal or transvector control. vector control is implementable in both synchronous motor and induction motor drive. still, there is an excellent room of interest of research in the design of new control techniques for the variable speed operation of induction motor because the induction motors are considered as the most critical industrial load of the electric power system. it is going to be a prevailing fact that electrical energy consumption is effectively reduced with the effective control of the speed of the electric motor drive. hence, we can have functional conservation of energy. field oriented control is effectively implemented to control the induction of motor drives and synchronous motor drives [30]. the control mentioned above technique is developed for the electric motor applications with high performance, which are required to operate efficiently over the rated speed, able to generate the full torque even at stand-still and have the better dynamics in performance which must include the fastest acceleration, the deceleration in its operation. however, this method is getting more attraction in the lower performance application predominantly owing to the motor’s size, initial cost, and electric power consumption with this controller based on the field-oriented techniques [5]-[10]. typical forms of crh3 is high-speed trains and more and more are becoming in china, popular. their traction driver systems consist of traction driver systems, a transformer of traction, a converter of traction, and motors with traction [14]. to improve their performance, detailed simulation results are required. thus, a suitable simulation method needs to be investigated [15]. on 11 april 2008[11], the first chinese-built crh3 (crh3-001c) was unveiled. the trains are designed to run at 217 mph (350 km/h). crh3-001c reached a top speed of 394.3 km/h (245.0 mph) on 24 june 2008 during the beijing to tianjin high-speed line test [12]. nowadays, the researchers are looking forward to having high impact research with practical implications on the variable speed drive with induction motors because this electric machine is considered as a primary building block of industrial load in the electric power system. it has gone through to be a prevailing fact that electrical energy consumption is effectively reduced with the effective control of the speed of the electric motor drive. the most commonly used in the speed and torque control of the induction motor drive is named as voltage control, control of frequency, control of rotor resistance used with the external circuit, the voltage over frequency control because the speed is the slave of frequency, control of flux, control of slip speed, slip power control alongwith all the appropriate control techniques. here techniques, as mentioned above, are the scalar control techniques of an induction motor. however, these control techniques show the coupling effect and inferior transient response [11-19]. this research article shows the implementation of the vector control method to remove the above mentioned two issues encountered with induction motor-based drives. our aim of using the vector control method is to decompose the stator current with mannan (et al) dynamic modeling and vector control of ac induction traction motor in china railway (115 – 125) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 117 component generating magnetic-field ids and component generating torque iqs. both the components can be individually controlled to have higher performance induction motor based electric drive in comparison with the dc motor bases drive [2]-[4]. this structure has several important advantages: concepts are very intuitive and easy to understand, it can be applied to a wide range of systems, it is easy to consider the multivariable case, dead times can be compensated, easy inclusion of non-linearities in the model, simple handling of constraints, it is easy to implement the resulting controller, this methodology is appropriate for the inclusion [20-29]. this research article illuminates the transient modeling of induction motor with vector control, speed control of induction motor based electric drive, and hence the control of induction motor is verified in the simulink-matlab software. by the recent research with the practical implementations, it has appeared that the vector control method for electric drives has become dominant over the scalar control, and this will be effectively implemented in the industry as a standard. 2. dynamic modeling of ac asynchronous-motor a. mathematical modeling of a synchronous motor in three-phase stationary coordinate system the dynamic mathematical prototypical model of induction motor is a higher-order, non-linear, strong-coupled multi-variable coordination system. its static and dynamic characteristics and control technology are far more complex than dc motors. to improve system performance, optimize control modes, and improve design methods, it is mandatory to discuss the mathematical model of the particular electric motor further. assumption: 1. set the magnetomotive force generated by the symmetry of the three-phase windings to be distributed along with the sinusoidal law round the air-gap field. 2. let us ignore the saturation of the magnet circuit. the self-inductances and mutual inductances of each winding are the linear functions. 3. core losses can be ignored 4. the effects of variation in the frequency also corresponding temperature change on winding’s resistance are not reflected in the calculation. under the assumptions mentioned above, the four equations can be obtained. [ 𝑢𝐴 𝑢𝐵 𝑢𝐶 𝑢𝑎 𝑢𝑏 𝑢𝑐 ] = [ 𝑅𝑠 0 0 0 0 0 0 𝑅𝑠 0 0 0 0 0 0 𝑅𝑠 0 0 0 0 0 0 𝑅𝑟 0 0 0 0 0 0 𝑅𝑟 0 0 0 0 0 0 𝑅𝑟] [ 𝑖𝐴 𝑖𝐵 𝑖𝐶 𝑖𝑎 𝑖𝑏 𝑖𝑐 ] + 𝑝 [ 𝜓𝐴 𝜓𝐵 𝜓𝐶 𝜓𝑎 𝜓𝑏 𝜓𝑐 ] (1) where ua, ub, uc, ua, ub, uc— instantaneous-values of the phase voltages of stator and rotor; ia, ib, ic, ia, ib, ic— instant values of phase currents of stator and rotor; a, b, c, a, b, c— the full flux linkage of each phase winding; rs, rr—rotor and stator winding resistance. [ 𝜓𝐴 𝜓𝐵 𝜓𝐶 𝜓𝑎 𝜓𝑏 𝜓𝑐 ] = [ 𝐿𝑠 𝐿ab 𝐿 ac 𝐿 aa 𝐿 ab 𝐿 ac 𝐿 ba 𝐿𝑠 𝐿bc 𝐿 ba 𝐿 bb 𝐿 bc 𝐿 ca 𝐿 cb 𝐿𝑠 𝐿ca 𝐿 cb 𝐿 cc 𝐿 aa 𝐿 ab 𝐿 ac 𝐿𝑟 𝐿ab 𝐿 ac 𝐿 ba 𝐿 bb 𝐿 bc 𝐿 ba 𝐿𝑟 𝐿bc 𝐿 ca 𝐿 cb 𝐿 cc 𝐿 ca 𝐿 cb 𝐿𝑟 ] [ 𝑖𝐴 𝑖𝐵 𝑖𝐶 𝑖𝑎 𝑖𝑏 𝑖𝑐 ] (2) rotor mutual inductance lmr the maximum mutual magnetic flux interlinking with the rotor one-phase winding; lms = lmr, laa = lbb = lcc = lms + lls, laa = lbb = lcc = lms + llr; torque equation is described as: 𝑇𝑒 = 1 2 𝑛𝑝 [𝑖𝑟 𝑇 𝜕𝐿𝑟𝑠 𝜕𝜃𝑟 𝑖𝑠 + 𝑖𝑠 𝑇 𝜕𝐿𝑠𝑟 𝜕𝜃𝑟 𝑖𝑟] (3) the mathematical equation for the motion if the viscous friction and torsional elasticity mannan (et al) dynamic modeling and vector control of ac induction traction motor in china railway (115 – 125) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 118 for drive contrivance of the electric drive’s system are neglected, the torque balance equation of the asynchronous motor drive system is 𝑇𝑒 = 𝑇𝐿 + 𝐽 𝑛𝑝 𝑑2𝜃𝑟 𝑑𝑡2 = 𝑇𝐿 + 𝐽 𝑛𝑝 𝑑𝜔𝑟 𝑑𝑡 (4) b. coordinate transformation traction inverters are consisting of the voltage-source inverter (vsi) and coordinate transformation principle 1. principle of the mmf equivalent 2. power invariance principle 3. equivalency in the current transformation matrix within this calculation 4. equivalency in the voltage transformation matrix 1）transformation with 3/2 rule conversion with the transformation between the three-phase stationary reference frame and the two-phase stationary-reference frame is referred to as 3/2 transformations. figure 1 drawn above two coordinate systems, let the adequate turns of the individual phase of the three-phase winding be n3, and the number of turns of the individual phase of two-phase winding is n2, and mmf of individual phase is the numerical product of the sufficient number of turn and current. with the condition as given below; 3-phase mmf = two-phase mmf so as seen in fig.1 𝑁2𝑖𝑎 = 𝑁3𝑖𝐴 − 𝑁3𝑖𝐵 𝑐𝑜𝑠 6 0 ° − 𝑁3𝑖𝐶 𝑐𝑜𝑠 6 0° = 𝑁3 (𝑖𝐴 − 1 2 𝑖𝐵 − 1 2 𝑖𝐶) (5) 𝑁2𝑖𝛽 = 𝑁3𝑖𝐵 𝑠𝑖𝑛 6 0 ° − 𝑁3𝑖𝐶 𝑠𝑖𝑛 6 0 ° = √3 2 𝑁3(𝑖𝐵 − 𝑖𝐶) the zero-axis current is also augmented into the conversion, by considering total power before and after the conversion of transformation is equal, 𝐶𝑖𝐶𝑢 𝑇 = 𝐶3/2𝐶3/2 𝑇 = 𝐸 3 2 ( 𝑁3 𝑁2 )2 = 1,2𝐾2 = 1 (6) where ⇒ 𝑁3 𝑁2 = √ 2 3 , 𝐾 = √2 2   b bn i3 i2n i2n an i3 cn i3 c  60  60 a fig. 1 vector space of three-phase & the twophase reference frame and winding’s mmf   d q ( ) sifs i  di cosiq sindis   qi siniq cosid i s fig. 2 stationary and rotating reference frame of two-phase & mmf let c3/2 denote the transformation matrix from the three-phase reference frame to the two-phase coordinate system. transformation is done from a two-phase reference frame to a three-phase reference frame. in fig.2 explained the transformation of αβ stationary frame into d-q rotating frame of mmf. c. mathematic model of induction motor in two-phase stationary reference frame by using clark transformation to convert the current, voltage, linked flux, and em torque of the rotor and the stator in equations mannan (et al) dynamic modeling and vector control of ac induction traction motor in china railway (115 – 125) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 119 to the two-phase stationary reference frame, the mathematical model of the asynchronous motor in the αβ reference frame can be calculated, as shown in the equation. the voltage equation could be depicted as follows. [ 𝑢𝑠𝛼 𝑢𝑠𝛽 𝑢𝑟𝛼 𝑢𝑟𝛽 ] = [ 𝑅𝑠 + 𝐿𝑠𝑝 0 𝐿𝑚𝑝 0 0 𝑅𝑠 + 𝐿𝑠𝑝 0 𝐿𝑚𝑝 𝐿𝑚𝑝 𝜔𝑟𝐿𝑚 𝑅𝑟 + 𝐿𝑟𝑝 𝜔𝑟𝐿𝑟 −𝜔𝑟𝐿𝑚 𝐿𝑚𝑝 −𝜔𝑟𝐿𝑟 𝑅𝑟 + 𝐿𝑟𝑝 ] [ 𝑖𝑠𝛼 𝑖𝑠𝛽 𝑖𝑟𝛼 𝑖𝑟𝛽] (7) the torque equation could be depicted as follows. 𝑇𝑒 = 3 2 𝑛𝑝𝐿𝑚(𝑖𝑠𝛽𝑖𝑟𝛼 − 𝑖𝑠𝛼𝑖𝑟𝛽) = 3 2 𝑛𝑝(𝑖𝑠𝛽𝜓𝑠𝛼 − 𝑖𝑠𝛼𝜓𝑠𝛽) (8) the equation of motion is invariant, np number of poles, lm mutual inductions, 𝜓𝑠𝛼,𝛽 stator flux, 𝑖𝑠𝛼,𝛽 stator current and 𝑖𝑟𝛼,𝛽 rotor current. it can be seen that the rotating transformation excludes the influence of the angle between the stator and rotor winding on linked-flux and torque. it converts the flux linkage equation of nonlinear variable parameters into a steady linear equation. however, the nonlinear coupling of the voltage equation increases. d. mathematic model of asynchronous motor in two-phase synchronous probationary reference frame similarly, park transformation is utilized to convert voltage (v), current (i), flux linkage also the torque of the stator and rotor in the equation to the two-phase rotating reference frame d-q, and the mathematical model of the asynchronous motor in d-q reference frame can be calculated. the voltage equation could be depicted as follows. [ 𝑢sd 𝑢sq 𝑢rd 𝑢rq ] = [ 𝑅𝑠 + 𝐿𝑠𝑝 −𝜔𝑠𝐿𝑠 𝐿𝑚𝑝 −𝜔𝑠𝐿𝑚 𝜔𝑠𝐿𝑠 𝑅𝑠 + 𝐿𝑠𝑝 𝜔𝑠𝐿𝑚 𝐿𝑚𝑝 𝐿𝑚𝑝 −𝜔sl𝐿𝑚 𝑅𝑟 + 𝐿𝑟𝑝 −𝜔sl𝐿𝑟 𝜔sl𝐿𝑚 𝐿𝑚𝑝 𝜔sl𝐿𝑟 𝑅𝑟 + 𝐿𝑟𝑝 ] [ 𝑖𝑠𝑑 𝑖𝑠𝑞 𝑖𝑟𝑑 𝑖𝑟𝑞] (9) the torque equation could be depicted as follows. 𝑇𝑒 = 3 2 𝑛𝑝𝐿𝑚(𝑖𝑠𝑞𝑖𝑟𝑑 − 𝑖𝑠𝑑𝑖𝑟𝑞) (10) np number of poles, lm mutual inductions, 𝑖𝑠𝑑,𝑞 stator current and 𝑖𝑟𝑑,𝑞 rotor current in rotating frame. the above equation of motion is invariant; it is observed that fluxlinkage and torque-equation in the rotating reference frame are similar as in stationary two-phase orthogonal reference frame, and only the subscript changes. the rotating reference frame presents a rotating speed w1, which is the rotating-orthogonal reference frame. when w1=0, the calculated or mathematics model in the rotating reference frame is the same as the mathematical model in the stationary coordinate system, and the introduction of the rotational speed w1 improves the degree of freedom of system control. field-oriented control is achieved by selecting different w1. 3. control of ac asynchronous traction motor a. fundamental concepts and principle of field-oriented control for mathematical simplification take rotating dq frame, quadrature and direct axis. consider that the d-axis align with the rotor flux vector, which is called the synchronously rotating reference frame aligned with the rotor’s flux linkage. hence d-axis aligns with the vector of the flux of the rotor. hence accordingly, { 𝜓𝑟𝑑 = 𝜓𝑟 𝜓𝑟𝑞 = 0 () mannan (et al) dynamic modeling and vector control of ac induction traction motor in china railway (115 – 125) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 120 𝜓𝑟𝑑,𝑞 is rotor flux, with the purpose to ensure the x-axis and the rotor flux vector always coincide with each other. 𝑑𝜓𝑟𝑑 𝑑𝑡 = 𝑑𝜓𝑟𝑞 𝑑𝑡 = 0 (12) substituting (11) and (12) into (9), the rotor flux ψr could be depicted as 𝜓𝑟 = 𝐿𝑚 𝑇𝑟𝑝+1 𝑖𝑠𝑑 = 𝐿𝑚 𝜔𝑠𝑙𝑇𝑟 𝑖𝑠𝑞 (13) where tr nominates the excitation timeconstant of the rotor-flux and hence tr =lm/rr. when the isd stays constant, ψr = lmisd. and the slip angular frequency could be calculated by 𝜔𝑠𝑙 = 𝐿𝑚 𝑇𝑟𝜓𝑟 𝑖𝑠𝑞 = 1+𝑇𝑟𝑝 𝑇𝑟𝑖𝑠𝑑 𝑖𝑠𝑞 (14) according to the calculation above, the dynamic vector diagram could be drawn as in fig.1. fig. 3 rotor flux field orientation (the daxis is aligned with λr). reference of the slip angular frequency could be depicted 𝜔𝑠𝑙 ∗ = 𝑖𝑠𝑞 ∗ 𝑖𝑠𝑑 ∗ 1+𝑇𝑟𝑝 𝑇𝑟 (15) thus, the target stator frequency could be calculated as 𝜔𝑠 ∗ = 𝜔𝑠𝑙 ∗ + 𝜔𝑟 (16) 𝜑 = ∫ 𝜔𝑠 ∗𝑑𝑡 = ∫(𝜔𝑠 ∗ + 𝜔𝑟)𝑑𝑡 (17) according to the calculation of angle of motor is based on estimation of angle in (17). the rotor flux ψr and phase angle φ could be calculated by the current target isd* and isq* according to the structure shown in fig.4. 1 m r l t p +  +m r l t  pg φωs * ωr ωsl *isq * isd * ψr fig. 4. calculation structure of ψr and φ for stability of system in relation of torque and stability the system is lyapunov stable. if and only uq(t) is restricted to the open interval (a-, a+) that is 𝑢𝑞− > 𝑎− , 𝑢𝑞+ < 𝑎 + (18) in other words, the required condition for the system to have a unique point of equilibrium system. 4. simulation & results as per the presented analysis, an indirect field orientation-based control diagram of the induction motor is fabricated, as shown in fig 5. through the speed closed-loop, the value of it is measured with the given value of the speed through the speed close loop, and after that, it is compared with actual it to get the voltage q axis component value through the closed-loop. the given value of im can be calculated by the given flux at steady-state conditions, through the flux closed loop to get the d-axis component voltage. then the motor can be driven through the coordinate transformation. the decoupling of current and voltage is achieved in this process through the coordinate transformation. because of the stator angle is used in the coordinate transformation, so this paper uses the rotor field orientation method to get the slip angular velocity. the detailed principle has been explained above. mannan (et al) dynamic modeling and vector control of ac induction traction motor in china railway (115 – 125) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 121 svpwm + − + 3 / 2s r * n n * r  r  t u m u α u β u r  s  sl  asr atr apr m r 1 l t p + m 1 l m r l t + − − dq  im n e  abc i e  ÷ t i m i  +e t i m i * t i * m i + fig.6 control block diagram of vector control the motor parameters and the test case are shown as follows: table i: simulation model parameters sym bol quantity value pn rated power 562kw un rated voltage 2700v fn rated frequency 138hz np pole pairs 2 ten rated torque 692n·m rs resistance of stator 0.1065ω rr resistance of rotor 0.0663ω lls inductance of stator 0.00131h llr inductance of rotor 0.00139h lm mutual-inductance 0.05361h nn rated speed 4100r/min udc dc-link voltage 3000v j inertia 2kg·m2 sn rated slip 0.001 f switching frequency 1khz t simulation time 2s tl load torque 0s:0n 1s:1000n n* given speed 0s:1500rpm 0.5s: 3000rpm 1.5s: 2000 rpm among the table, the un represents the rated voltage of the motor, the udc represents the dc bus supply, the pn represents the rated power of the motor, the fn represents the rated frequency of the motor, the lm represents the excitation inductance, ls characterizes stator’s inductance value, lr characterizes inductance, the rs represents the stator resistance, the rr characterizes rotor resistance, np characterizes pole-pair of the induction motor, ts characterizes sample time used in the modulation, the j represents the moment of inertia. the simulation results are given below: i sa ,i sb ,i s c/a , 1 00 0/ di v 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 t/s 0.06 0.10.08 -1000 1000 -200 0 200 1.16 1.21.18 -200 0 200 1.86 1.91.88 fig. 7 three-phase stator current mannan (et al) dynamic modeling and vector control of ac induction traction motor in china railway (115 – 125) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 122 fig. 8 output speed fig. 9 output em torque it is presented in the simulation that the torque changes quickly, whatever in load torque sudden change or speed sudden change, results in the fast-dynamic performance. moreover, the current response quickly, the current is smooth, and the sinusoidally is high. however, at the start time, the torque has two different rising slopes, instead of reaching a constant value quickly. this phenomenon is different from the rapid changes behind because the torque-current component approached the corresponding constant torque, which is calculated at the beginning, showing the correctness of the speed and torque loop parameters. the rotor flux does not quickly reach the given value but is divided into two slopes in rising, so the flux linkage loop does not reach the desired result. since the torque is controlled by both the rotor flux and the current torque component, the torque will not reach the given value if the rotor flux does not reach the given. it is wellknown that in addition to vector control (vc), n (r /m in ), 1 0 0 0 /d iv 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 t/s 1515 1525 0.15 0.25 0.35 0.45 0.55 3015 3020 3025 0.9 0.94 0.98 1.02 1.06 1.1 1900 2000 2100 2200 1.65 1.7 1.75 1.8 1.85 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 1.8 t e /n ,1 0 0 0 /d iv t/s mannan (et al) dynamic modeling and vector control of ac induction traction motor in china railway (115 – 125) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 123 high-performance control of the motor, as well as direct torque control, mpcmodel predictive control. the comparative analysis of the vc and dtc are shown in table ii. moreover, the control performance of the three control strategies is shown in table iii. table ii: the comparative analysis of dtc and vc performanc e& characteris tics dtc vc flux control stator flux rotor flux torque control bang-bang control, with torque ripple continuous control, smoother coordinate transformat ion clark transformat ion simple park transformat ion complicate d rotor parameter variation no yes speed range not wide enough relatively wide table iii: the comparative analysis of three control strategies vc ➢ limited current loop bandwidth at the low switching frequency, low dynamic performance ➢ controller design, the setting is more complicated, and the parameter dependence is stronger. ➢ need to design complex pulse mode switching strategies ➢ when using off-line optimized pwm, such as shepwm, the switching angle is required to be continuous. dtc ➢ simple structure, fast dynamic response ➢ good parameter robustness, less controller parameters to debug ➢ when operating it at a lowswitching rate (frequency), ripple torque in the steadystate is higher, which is not suitable for passenger trains ➢ it is difficult to balance current limiting with transient process mpc ➢ simple concept, multiobjective optimization control (low switching frequency and low switching loss), less debugging parameters ➢ comparable to the dynamic performance of dtc and the steady-state performance of foc ➢ integrated online/offline synchronization optimized pwm algorithm for easy current thd and higher efficiency than traditional foc ➢ easy to switch smoothly between any different pulse modes ➢ relatively high computational complexity 5. conclusion the parameters of the simulation motor are referred to as the crh3 emu. the simulation result verified the principle by analyzing the simulation, and the following conclusions is obtained. the asynchronous motor under the control of the vector adopts the speed and current double-loop structure, the torque response is rapid, and the speed mannan (et al) dynamic modeling and vector control of ac induction traction motor in china railway (115 – 125) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 124 changes smoothly. it can have good steadystate performance when the regulator's parameters are suitable. the magnetic field has not yet been fully established in the starting process, so the necessary conditions to guarantee the starting constant torque is to make the rotor flux quickly reach the given value. in addition, because the rotor flux is open-loop in this simulation, the rotor flux cannot make the desired change regardless of how regulator parameters are adjusted, so the starting process is not ideal. references [1] struharňanský, ľuboš, et al. "vector control techniques for traction drive with induction machines-comparison." procedia engineering 192 (2017): 851856. [2] bose, bimal k. "power electronics and ac drives." englewood cliffs, nj, prentice-hall, 1986, 416 p. (1986). [3] krishnan, ramu. electric motor drives: modeling, analysis and control. prentice hall, 2001. [4] mishra, ambarisha, et al. "modeling and implementation of vector control for pm synchronous motor drive." ieeeinternational conference on advances in engineering, science and management (icaesm-2012). ieee, 2012. [5] fitzgerald, arthur eugene, et al. electric machinery. vol. 5. new york: mcgrawhill, 2003. [6] blaschke, felix. "the principle of field orientation as applied to the new transvector closed-loop system for rotating-field machines." siemens review 34.3 (1972): 217-220. [7] baader, uwe, manfred depenbrock, and georg gierse. "direct self control (dsc) of inverter-fed induction machine: a basis for speed control without speed measurement." ieee transactions on industry applications 28.3 (1992): 581588. [8] vas, peter. vector control of ac machines. vol. 22. oxford university press, usa, 1990. [9] novotny, donald w., and thomas a. lipo. vector control and dynamics of ac drives. vol. 1. oxford university press, 1996. [10] vas, p. "sensorless vector and direct torque control oxford university press." new york, usa (1998). [11] tangshan rolls out its first 350 km/h train". railway gazette international. 11 april 2008. retrieved 30 june 2008. [12] velaro sets chinese speed record". railway gazette international. 27 june 2008. archived from the original on 22 march 2010. retrieved 29 may 2010. [13] ortega, r., escobar, g., & barabanov, n. (2000, december). direct torque control of induction motors: stability analysis and performance improvement. in isie'2000. proceedings of the 2000 ieee international symposium on industrial electronics (cat. no. 00th8543) (vol. 1, pp. 259-264). ieee. [14] lu, q. f., wang, b., huang, x. y., ma, j. e., fang, y. t., yu, j., & cao, w. p. (2011). simulation software for crh2 and crh3 traction driver systems based on simulink and vc. journal of zhejiang university-science a, 12(12), 945-949. [15] song, l.m., 2009. the transmission and control of emu. the chinese railway press, beijing, china, p.134-217 (in chinese). [16] leonhard, w. (2001). control of electrical drives. springer science & business media. [17] vas, p. (1990). vector control of ac machines (vol. 22). oxford university press, usa. [18] c. french and p. acarnley, “direct torque control of permanent magnet drives,” ieee transactions on industry applications, vol. 32, no. 5, pp. 1080– 1088, september/october 1996. [19] l. tang, l. zhong, m. rahman, and y. hu, “a novel direct torque control for interior permanent-magnet synchronous machine drive with low ripple in torque and flux: a speed-sensorless approach,” ieee transactions on industry applications, vol. 39, no. 6, pp. 1748– 1756, march 2003. [20] t. geyer, model predictive control of high power converters and industrial drives. west sussex, u.k.: wiley, 2017. [21] kumar, danduproul kiran. “a matlab / simulink model of pmsm drive using direct torque control with space vector modulation.” (2016). [22] j. rodriguez and p. cortes, predictive control of power converters and mannan (et al) dynamic modeling and vector control of ac induction traction motor in china railway (115 – 125) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 125 electrical drives. hoboken, nj, usa: wiley, 2012. [23] abad, gonzalo, ed. power electronics and electric drives for traction applications. wiley, 2017. [24] m. j. melfi, s. evon, and r. mcelveen, "induction versus permanent magnet motors," ieee industry applications magazine, vol. 15, no. 6, 2009. [25] j. h. lee, “model predictive control: review of the three decades of development,” int. j. control. autom. syst., vol. 9, no. 3, pp. 415–424, 2011 [26] y. zhang, b. xia, h. yang and j. rodriguez, "overview of model predictive control for induction motor drives," in chinese journal of electrical engineering, vol. 2, no. 1, pp. 62-76, june 2016, doi: 10.23919/cjee.2016.7933116. [27] l. dube and e. bayoumi, "robust dtc against parameter variation for three phase induction motor drive systems," 2020 international conference on electrical, communication, and computer engineering (icecce), istanbul, turkey, 2020, pp. 1-6 [28] a. ammar, a. bourek and a. benakcha, "efficiency optimization for sensorless induction motor controlled by mras based hybrid foc-dtc strategy," 2017 international conference on control, automation and diagnosis (iccad), hammamet, 2017, pp. 152-157, doi: 10.1109/cadiag.2017.8075648. [29] n. el ouanjli, a. derouich, a. chebabhi and m. taoussi, "a comparative study between foc and dtc control of the doubly fed induction motor (dfim)," 2017 international conference on electrical and information technologies (iceit), rabat, 2017, pp. 1-6, ‘ [30] y. w. yhya, r. m. sharkawy and m. r. hamouda, "comparative study of different drive controller for a traction system," 2019 21st international middle east power systems conference (mepcon), cairo, egypt, 2019, pp. 5964. vol. 3, no. 2 | july december 2020 sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 99 current status of microalgae to produce biogas through pretreatment of lignocellulosic waste in the era of 21-century ali raza ishaq1, maleeha manzoor2, jawad ahmad3, qurat-ul-ain ahmad4, fouzia tabssum5, asma chaudary4 , saif ur rehman2 , tehreem rafique6, ayesha noor2 abstract: modern day civilization is dependent on energy generation by fossil fuels. but the major drawback of using fossil fuels is environmental pollution. microalgae are potential candidate for production of various products of interest, such as proteins, mini food, pigments and triglycerides that can be converted into biofuels. lignocellulosic feedstocks are the most abundantly available raw material of plants that can serve as a promising feedstock for cultivating bacteria, fungi, yeast and microalgae to produce biofuels and other value-added products. owing to the abundant availability of these low/no cost substrates, can be utilized as feedstocks for cultivating microalgae to generate biogas/biodiesel. likewise, there is much room to exploit defatted algal biomass to be used as animal/fish feed and oil producing/accumulating genes knowledge in future to produce high and good quality biodiesel and biogas. keywords: lignocellulosic substrate; pre-treatment; microalgae/cyanobacteria; biogas; problems; animal feed 1. introduction now-a-days energy resources are inadequate in numbers for desirable production of energy with less frugal resources [1]. energy and environmental pollution are included in the top ten problems of the world. the desirable amount of oil and other energy products are reduced, and energy requirements reach at elevated point in this modern era. according to world trend plus’s 1 state key laboratory of biocatalysis and enzyme engineering, environmental microbial technology center of hubei, college of life science, hubei university, wuhan 430062 china 2 department of zoology, government college university faisalabad punjab pakistan 3 department of mechanical engineering, university of engineering & technology, lahore 4 division of science, university of education, lahore 5 department of zoology, university of education, lahore 6 department of ecology and environmental science, east china normal university corresponding author: maleehamanzoor@gcuf.edu.pk association: energy sector in pakistan, oil consumption was reported at 498.197 barrel/day in 2018 and oil demand is about to increase upto 60%. fossil fuels are nonrenewable resources that are eradicated rapidly and can cause drastic effect on economic cost of any developing country [2, 3]. the depletion of fossil fuel is affecting certain environmental conditions such as abiotic factors like temperature, climate, mailto:maleehamanzoor@gcuf.edu.pk ali raza (et al.), current status of microalgae to produce biogas through pretreatment of lignocellulosic waste in the era of 21-century (pp. 99 114) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 100 greenhouse effect [4] and ultra-violet radiation [5, 6]. it is reported earlier that chinese people used microalgae (nostoc sp.) to overcome the famine condition about 2000 year ago [7]. biomass mainly consisted of compost and manure which may be terrestrial and aquatic [8]. biomass feedstock is a renewable source of energy for the output of biogas [9] and biofuel through anaerobic microalgal digestion [10] as show in fig, 1. terrestrial biomass is a promising agent to produce renewable energy whereas, aquatic biomass is easily available to be produce energy at large scale without causing any environmental hazards and economically feasible too [8]. the most promising way to obtain maximum energy with less economic cost is decomposition of biomass by using microalgae [11, 12]. algae is unicellular and simple multicellular organisms with photosynthetic pigments such as chlorophyll a, b, c and other accessory pigments. there are several globally dominating species of microalgae being cultivated at large scale and produce products of commercial importance with low cost such as isochrysis, chaetoceros, arthrospira and dunaliella [13]. microalgae effectively break the lignocellulosic wastes without production of toxic material. advantages of microalgae for biomass treatment is shown in table i. microalgae are cultivated autotrophically, heterotrophically and mixotrophically based on its mode of nutrition. heterotrophic algae rely on glucose or other organic material as carbon source. mixotrophically grown microalgae have ability to utilize both organic and inorganic carbon sources such as chlorella sp. and accumulate biomolecules such as carbohydrates, lipids and proteins [19]. microalgae are capable of producing biofuels like methane [7, 9, 20], biodiesel [3, 21] and bio hydrogen in a simple photobioreactor [22] and biogas as shown in figure 02 fig 1:overview microalgal bio-energy products through pre-treatment of lignocellulosic wastes ali raza (et al.), current status of microalgae to produce biogas through pretreatment of lignocellulosic waste in the era of 21-century (pp. 1 24) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 101 table i advantages of using microalgae/cyanobacteria for biogas production sr no advantages of using microalgae/cyanobacteria for biogas production references 01 microalgae/cyanobacteria can grow at high levels of co2 throughout year [12, 14] 02 microalgae/cyanobacteria can grow in marine/brackish, freshwater and wastewaters thus less competition for arable land [15][40[16] [17, 18]] 03 microalgal biomass is a rich source of other coproducts such as gasoline and biohydrogen etc. [17] 04 microalgae/cyanobacteria are ubiquitous and serves as a promising candidate to generate high rates of productivity [5, 16] 05 they play important role in oxygen production. nitrogen cycle and reformed the oxidizing environment from reducing environment. 06 the requirements for nourishing the microalgae/cyanobacteria is very simple and prosperous agent to convert the solar energy into co2, also originator of various feedstock for energy producing compound such as lipids, carbohydrates and protein. 2. lignocellulosic waste food and plant-based waste known as lignocellulosic waste is produced up to 1.3 billion ton/year around the world [23]. lignocellulose waste is an inexpensive and renewable energy source to produce high yield of biomass approximately 50% [24] and helps in carbon dioxide sequestration [25] globally throughout the year. lignocellulose is mainly composed of hemicellulose, lignin, cellulose, phenolics [26] and other inorganic materials [27], their rate of production totally depends on plant species [28]. major lignocellulosic biomass resources are manure, woodlot arising, crop residues, agroindustrial wastes, sugarcane, bagasse, sawdust and consecrated energy crop table ii. 2.1. cellulose: cellulose is most abundant polysaccharide in biosphere and chief ingredient of higher plants, brown, red and green algae. cellulose is unbranched polymer, formed by monomer of glucose that are linked by β1,4glycosidic bond. its degree of polymerization is about to 14000 – 15000 glucose monomer each monomer rotates at 180o angle. fig 2: basic structure of photobioreactor ali raza (et al.), current status of microalgae to produce biogas through pretreatment of lignocellulosic waste in the era of 21-century (pp. 1 24) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 102 table ii major lignocellulosic wastes and their composition sr no: lignocellulose wastes cellulose (wt %) hemicellulose (wt %) lignin (wt %) references 01 corn stalks 35.0 16.8 7.0 [29] 02 sugarcane bagasse 40.0 27.0 10.0 03 wheat straw 32.9 24.0 8.9 04 soft wood (spruce) 44.7 22.9 30.6 [30] 05 hard wood (beech) 45.6 25.9 23.8 06 grass (switch grass) 32.2% 24.4 % 23.3% 2.2. hemicellulose the second most important polymer in this biosphere is hemicellulose which has random and amorphous structure, consisted of heteropolymer such as xyloglucan, glucomannan, arabinoxylan, glucuronoxylan, galactomannan and xylans [31]. due to this, its chemical composition deviated from species to species, however, xylans and glucomannan are present in hard wood or soft wood respectively[31]. hemicellulose makes up 15 – 35% plant biomass that are joined with cellulose by hydrogen bond, to lignin through covalent bond 2.3. lignin lignin are large, complex and crosslinked aromatic polymers that are formed by oxidative combinative conjugation of 4 hydroxy-phenyl-porpanoids [32]. lignin monomers are linked together through c-c and aryl ether linkage associating with varieties of functional group such as methoxy, phenolic hydroxy and adjacent aldehyde [33]. divergence in composition of bond and functional group depend on the plant’s species biomass. lignin provide strength and protect from stress condition by association with cellulose and hemicellulose. 3. pre-treatment of lignocellulosic waste: pre-treatment is a critical procedure for the biochemical renovation of lignocellulosic biomass into bioethanol, biogas, biohydrogen [34]. this process is essential to modify the cellulosic biomass for making large quantity of cellulose which is converted into the carbohydrate polymers (fermentable sugars) by the action of specific enzymes [35]. pretreatment of lignocellulosic wastes is completed through the acidic, basic and enzymatic courses [36]. recent research reveals that enzymatic hydrolysis is bestidentified technique to get high yield of biomass fig, 3. 3.1. acidic hydrolysis acidic method is one of the efficient methods to treat the lignocellulosic wastes through weak or strong acid hydrolysis specifically dilute acid hydrolysis that is most effective to gain high yield of biogas [28] . there are two types of weak acid hydrolysis usually: • extreme temperature for low solids loading (t> 160 °c, 5-10 wt% substrate concentration). ali raza (et al.), current status of microalgae to produce biogas through pretreatment of lignocellulosic waste in the era of 21-century (pp. 99 114) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 103 • low temperature for high solids loading (t≤160 °c, 10-40% substrate concentration). fig, 3. schematic representation of pre-treatment of lignocellulosic biomass procedure dilute h2so4 is most used acid for hydrolysis at 160-220 °c for few minutes. organic acids such as maleic acid, fumaric acid can also be used for dilute acid pre-treatment. the hydrolysate produced is a mixture of various valuable organic carbon, in the form of sugars and acts as a potential source to support microalgal growth and production of other targeted compounds such as oil and pigments [26]. treatment of lignocellulosic waste with concentrated strong acids such as h2so4 and hcl have been extensively used since they are powerful agents for cellulose hydrolysis with less enzyme requirement. some advantages of using concentrated acid hydrolysis are high monomeric sugar yield as well as slight temperature conditions are required. the most common drawback is alteration of natural cycles (carbon, nitrogen and water cycle). 3.2. alkaline method three bases are commonly used in lignocellulosic pre-treatment for generation of high energy amalgams such as biogas, biohydrogen and methane etc. i. calcium hydroxide ii. sodium hydroxide iii. ammonia lignocellulosic biomass must be discoloured through microbial enzymes which perform output chemical hydrolysis because enzymes demonstrate the high substrate and reaction specificity, activate beneath minor circumstances and not produce by-products [49]. due to this enzymatic method is precious for chemical, fuel, food and textile industries as well as in washing powder constructions and in paper making table iii. ali raza (et al.), current status of microalgae to produce biogas through pretreatment of lignocellulosic waste in the era of 21-century (pp. 1 24) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 104 table iii effect of biogas production through various pre-treatment methods sr. no pretreatment method enhancement of biogas % advantage disadvantage references 01 acidic 0-166 destruction of lignin and hemicellulose • high charge of acid • deterioration problem in digester • establishment of inhibitory substance [37] 02 basic 0-207 solubilizes the lignin and hemicellulose • high alkali meditation in digester • elevated cost of chemical 03 enzymatic 0-208 low energy feasting • unceasing adding mandatory • high cost of enzymes [38] 4. wastes water treatment in any developing country, quantity of wastewater production every day is gigantic because of growing population and swift industrialization. due to this, water pollution is one of the greatest life-threatening environmental problem [18, 39]. countless number of methods are adopted for treating the wastewater that cause pollution in environment, all of these are not economically feasible but one of the best methods for treating wastewater by microalgae that is economical and eco-friendly too. this method is also known as microalgae-based wastewater treatment (mbwt)[40]. one of advantages of using microalgae based wastewater treatment is that they have capability to remove heavy metals, inorganic ions and other organic material [16]. following types of wastewater are being treated by cultivating microalgae. 1. sewage wastewater 2. municipal wastewater 3. industrial wastewater both quantitative and qualitative characteristics of lipids content in algal biomass fluctuate due to variable growth conditions such as temperature, ph, light intensity and nutrition media (concentration of nitrogen, iron, phosphate and other inorganic molecules) [10, 21]. the microalgae cultivation is also effected by some other biotic factors such as pathogens and presence or absence of other algal species [41]. biomass treatment is depending on environmental conditions which influence the production of biogas. biogas and methane productivities is directly linked to conditions which is provided, ali raza (et al.), current status of microalgae to produce biogas through pretreatment of lignocellulosic waste in the era of 21-century (pp. 99 114) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 105 suitable condition gives us high level of biogas as shown in table iv. table iv methane and biogas yield of some microalgae species by using wastewater species optimum temperatu re reactor type type of waste(s)/ water metha ne (l ch4 g/vs) biogas yield (ml/gvs ) referenc es spirulina platensis 30 csrt/se mi continuou s/ batch sewage sludge 0.260.32 525-640 ml/gvs [42] chlorella vulgaris 28-31 batch domestic and municipal wastewate r 0.310.35 238-99 ml/gvs [43] chlorella sp. 35 batch seafood processin g 0.170.32 44 ml ch4/gv s (from chlorella sp.) 193 ml ch4/gv s (from processi ng of seafood [44] scenedesmus obliquus 35-37 batch secondar y waste effluents and municipal wastewate r, urban wastewate r 0.18 346 l ch4/kg vs 287 ml/gvs [45-47] chlamydomon as reinhardtii 38 batch wastewat er at different level of treatment 0.39 587 ml/gvs [39, 46] botrycoccus braunii 35 batch secondar y treated sewage from domestic 404 ml/ch 4 g vs 614.11 l/kg [48, 49] [50] ali raza (et al.), current status of microalgae to produce biogas through pretreatment of lignocellulosic waste in the era of 21-century (pp. 99 114) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 106 wastewate r, red nile tilapia effluent spirulina maxima 35 batch 330 361-382 l/kg vs [51] tetraselmis sp 35 batch urban wastewate r treatment 420 419-431 l/kg vs [52] 4.1. effect of temperature the effect of temperature on microalgae growth display significant role [53]. researchers found that optimal temperature for microalgal growth is 20-30oc although they can also grow in constant temperature. microalgae showed less growth when temperature is 16oc but showed increased growth rate as temperature increase up to 28±30oc. the microalgal growth rate is affected at 30oc, decreased at 32oc and almost 17% decline growth rate at 35oc [54]. when temperature is above the optimal temperature about 38oc that led to death of algal cell biomass due to denaturation of protein [55, 56]. 4.2. effect of ph microalgae grow in variable ranges of ph but the optimal ph for microalgae is 7-8 to show have maximum growth rate [48]. it is also observed that growth must be influenced by different ranges of ph such as at 6.5 ph growth rate is low but at 7-8 ph showed fastest growth rate [57]. when ph is above optimal range for example 9 than there is continuous decline in growth rate. it is also found that ph should be maintained at optimum range to sustain the growth of microalgae. that’s why ph is estimated to be third most important factor (after temperature and light intensity) for microalgae growth [54, 58, 59]. 4.3. effect of light diverse form of lights coming from different sources can be categorized as direct sunlight, indirect sunlight, fluorescent light and under dark, effect the growth rate of microalgae [27, 60]. under dark conditions, microalgae growth is not documented since light is crucial constituent for their growth and microalgal culture is set near to the window to have direct sunlight [61]. in case of direct sunlight, microalgae give maximum rate of growth specifically if fluorescent light is provided. microalgae growth is also dependant on light intensity, exposure and penetration thus, high light intensity damages the composition of pigments (phycobilin and phycoerythrin their nature different from other plant pigments based on molecular structure and absorption of light) and affects microalgal growth rate [27, 53, 60] . 4.4. effect of aeration continuous aeration is an essential factor for cultivating unicellular form of algae (chlorella sp.). thus, without any mean of aeration, no growth is recorded due to death of microalgae biomass cell. various modes for aeration are in use in a photobioreactor for better growth and enhanced amount algal fuel [62]. ali raza (et al.), current status of microalgae to produce biogas through pretreatment of lignocellulosic waste in the era of 21-century (pp. 99 114) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 107 5. inhibitors as by – product of lignocellulosic waste treatment inhibitors are those compounds which can stop or slow a biochemical process that may be competitive or non-competitive inhibitors. the by-product of pretreatment depends on the nature of chemical reaction and type of method which we use. inhibitors can stunt the growth of microorganism such as phenolic compound, aromatics, aliphatic acid, furan aldehydes, inorganic ions and other bioalcohols [63-65]. 5.1. phenolic compound we draw out phenolic compound during the pretreatment of lignin and wood extractives. phenolic compounds are longfamiliar with inhibiting activity against microorganism due to various strains of microalgae show the various responses against these types of compounds. some microalgae/cyanobacteria show complete resistant against phenolic compounds such as chlorella saccharophila, scenedesmus quadricauda, chlorella zofingiensis, coelastrum microporum and mesotaenium caldarorium [26]. 5.2. furans furans are union of furfural and hydroxymethyl furfurals (hmf) produced during the pretreatment of sugar and lignocellulosic waste with acids or base [66]. knowledge about the effect of furans on microalgae growth is scarce but a certain amount of furfural and hmf stimulate the inhibition of growth and ethanol production in diverse species of microalgae such as saccharomyces cerevisiae, zymomonas mobilis, pichia stipites and candida shehatae. 5.3. levulinic acid levulinic acid is produced by the decomposition of hmf and 1.16g/l of levulinic acid can stunt the growth of microalgae i.e sceletonema costatum, chlorella vulgaris and agmenellum quadruplicatum [66]. 5.4. fatty acid fatty acids are powerful part of lignocellulose waste material that are constitutent of wood of various trees such as eucalyptus. fatty acids also act as inhibitory agent in various species but their peculiar types such as oleic acid, palmitic acid and linoleic acids have pronounced inhibitory effect on many microalgae species such as s. capricornutum, monoraphidium contortum and chlorella vulgaris [26]. 6. biogas productivities microalgal species required specific medium for their growth or normal functioning on the substrate to produce large quantity of biogas yield/productivity [17, 67]. these are also helpful for treating the agroindustrial wastes help reducing the environmental pollution table v. 7. problems associated with anaerobic digestion of microalgae anaerobic digestion is not best known or beneficial method because a lot of complications faced while dealing with microalgae by cultivating on agro-industrial wastes [46]. some of the challenges are: low concentration of digestible substrate microalgae biomass is unique substrate for gaining high energy foodstuffs with lower commercial rate or low economically rate. micro-algae with low volatile solid piling quantity can be utilized as digestible substrate for extraction of less concentrated biomass [57]. 7.1. cell wall degradability cell wall degradability is major problem for anaerobic digestion because its rigidity effect the biogas productivity due to incomplete breakdown of cell wall [15, 57]. impregnation of carbohydrates and supplementary biomolecules make the cell wall more rigid. thus, biogas productivity from microalgae depends on the rigidity of cell wall [52]. cell wall provide protection to inner organic matter of microalgae from bacterial infection. bacteria can easily grow ali raza (et al.), current status of microalgae to produce biogas through pretreatment of lignocellulosic waste in the era of 21-century (pp. 99 114) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 108 and proceed anaerobic digestion after breaking down of microalgal cell wall. [46] fig, 4. table v microalgal biogas yield and biogas productivity sr. no microalgae biogas yield ml/g dm biogas productivity (p) ml/1v references 01 desmodesmus.sp 456 1436.40 [12] 02 d. armatus 440 1318.53 03 h. pluvialis 413 1261.63 04 s. obliqus 433 548.47 05 c. vulgaris 510 1944.80 06 c. sacharophilum 303 887.79 07 geminella.sp. 448 981.12 08 g. terricola 316 449.77 09 p. tricornutum 0.337l _ [15] 10 isochrysis galbana 0.22l _ 11 scenedesmus sp. 646 _ [68] 12 chlorella sp. 652 _ 13 cladophora glomerate 0.20m3/m3 d _ [9] 14 chara fragilis 0.12m3/m3 d _ 15 spirogyra neglecta 0.23m3/m3 d _ fig, 4. rigidity of cell wall in terms of modulus of rigidity) between biogas yield (ml/g vs along yaxis) and microalgal cell wall rigidity (modulus of rigidity (g) along xaxis. 0 50 100 150 200 250 300 350 2 g 4 g 6 g 8 g 1 0 g 1 2 g b io g a s y ie ld ( m l/ g v s ) rigidity of cell wall ( modulus of rigidity "g") biogas yield ali raza (et al.), current status of microalgae to produce biogas through pretreatment of lignocellulosic waste in the era of 21-century (pp. 1 24) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 109 solubilization and surface area effect the production of biogas by bacteria on inner organic matter [34, 69]. the solution for this problem is shown in fig, 5. fig, 5. solution of cell wall rigidity for enhancing biogas production fig, 6. effect of carbon-nitrogen ratio on biogas yield ali raza (et al.), current status of microalgae to produce biogas through pretreatment of lignocellulosic waste in the era of 21-century (pp. 1 24) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 110 7.2. carbon to nitrogen ratio (c: n) carbon to nitrogen ratio increase the complications for anaerobic digestion of microalgal biomass which indirectly affect the production of biogas [70]. high amount of nitrogen in the form of ammonia have inhibitory effect on anaerobic digestion, thus, nitrogen cause negative effect on biogas productivity indirectly [71] [50]. this problem can be solved by adding nutrients in the form of high carbon substrate for digestion that will reduce inhibitory effect of ammonia [71] as shown in fig, 6. 7.3. ammonia-nitrogen toxicity by hydrolysis of nitrogen containing compounds (protein, urea, and keratin), which are impregnated in algal cell cause ammonianitrogen toxicity. thus, ammonianitrogen concentration is passively entered in the cell by inhibiting methane synthesizing enzymes. due to movement of ammonia nitrogen ions imbalance the potassium concentration and decreased the biogas productivity [17]. this problem can be solved by removing acetogenic, hydrolytic and methanogenic bacteria from microalgal substrate. by removing bacteria, biogas production and anaerobic digestion increased. optimum concentration of ammonia-nitrogen is 3000 mg/l in a reactor above this figure may affect the productivity of biogas [71] as shown in fig, 7. fig, 7. effect of ammonia-nitrogen toxicity on biogas yield 7.4. effect of salinity microalgae (macrocystis pyrifera and tetraselmis sp.) are cultivated in salinehabitat to protect the agricultural land. lower alkaline earth metal is required for better anaerobic digestion in saline environment. higher concentration of alkaline in soil will change the ph and cause toxicity for methanogenic bacteria. higher salinity cause dehydration in bacterial cell due to higher osmotic pressure that cause inhibitory effect on anaerobic digestion. sodium, aluminium and magnesium change the chemistry of saline environment that is toxic for anaerobic processing of algal biomass and indirectly effect the biogas production [40]. 7.5. role of sulfide: microalgae in freshwater have less amount of sulfurated amino acid so during digestion h2s is produce in less amount. marine water has measurable amount of oxidized sulphide compounds that act as electron acceptor for sulphide reducing bacteria to convert organic compounds into h2s that cause corrosion in apparatus (photobioreactor). thus, this extra amount of h2s must be removed from apparatus which may affect less biogas productivity [40]. 8. conclusion: energy requisition now-a-days touched at higher level resulting in depletion of nonbiodegradable resources. that’s why truncated energy production effects economic value of any industrial country to overcome this crisis by using algal lignocellulosic biomass undergoes anaerobic digestion. to contract high yield of bioenergy product over exploitation of agro-industrial wastes, wastewater and other enduring biomass that is unsurpassed way to improve economy or to marmalade the natural environment. ali raza (et al.), current status of microalgae to produce biogas through pretreatment of lignocellulosic waste in the era of 21-century (pp. 99 114) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 111 list of abbreviation hmf_ hydro methyl furfurals mbwt_ microalgal based wastewater treatment acknowledgements not applicable references [1] khan, n.a. and h. el dessouky, prospect of biodiesel in pakistan. renewable and sustainable energy reviews, 2009. 13(67): p. 1576-1583. [2] rupprecht, j., from systems biology to fuel--chlamydomonas reinhardtii as a model for a systems biology approach to improve biohydrogen production. j biotechnol, 2009. 142(1): p. 10-20. [3] schenk, p.m., et al., second generation biofuels: high-efficiency microalgae for biodiesel production. bioenergy research, 2008. 1(1): p. 20-43. [4] medipally, s.r., et al., microalgae as sustainable renewable energy feedstock for biofuel production. biomed res int, 2015. 2015: p. 519513. [5] parmar, a., et al., cyanobacteria and microalgae: a positive prospect for biofuels. bioresource technology, 2011. 102(22): p. 10163-10172. [6] demirbas, a., biodiesel. 2008: springer. [7] spolaore, p., et al., commercial applications of microalgae. journal of bioscience and bioengineering, 2006. 101(2): p. 87-96. [8] aresta, m., a. dibenedetto, and g. barberio, utilization of macro-algae for enhanced co2 fixation and biofuels production: development of a computing software for an lca study. fuel processing technology, 2005. 86(14-15): p. 1679-1693. [9] baltrėnas, p. and a. misevičius, biogas production experimental research using algae. journal of environmental health science and engineering, 2015. 13(1): p. 18. [10] liu, z.-y., g.-c. wang, and b.-c. zhou, effect of iron on growth and lipid accumulation in chlorella vulgaris. bioresource technology, 2008. 99(11): p. 4717-4722. [11] roberts, k.p., s. heaven, and c.j. banks, comparative testing of energy yields from micro-algal biomass cultures processed via anaerobic digestion. renewable energy, 2016. 87: p. 744-753. [12] mudimu, o., et al., biotechnological screening of microalgal and cyanobacterial strains for biogas production and antibacterial and antifungal effects. metabolites, 2014. 4(2): p. 373-393. [13] zhu, c. and y. lee, determination of biomass dry weight of marine microalgae. journal of applied phycology, 1997. 9(2): p. 189-194. [14] mallick, n., et al., progress and challenges in microalgal biodiesel production. frontiers in microbiology, 2016. 7: p. 1019. [15] jankowska, e., a.k. sahu, and p. oleskowicz-popiel, biogas from microalgae: review on microalgae's cultivation, harvesting and pretreatment for anaerobic digestion. renewable and sustainable energy reviews, 2017. 75: p. 692-709. [16] salerno, m., y. nurdogan, and t.j. lundquist, biogas production from algae biomass harvested at wastewater treatment ponds. 2009: american society of agricultural and biological engineers. [17] murphy, j.d., et al., a perspective on algal biogas. 2015: iea bioenergy. [18] manzoor, m., et al., microalgal-bacterial consortium: a cost-effective approach of wastewater treatment in pakistan. punjab university journal of zoology, 2016. 31(2): p. 307-320. [19] mendez, l., et al., chlorella vulgaris vs cyanobacterial biomasses: comparison in terms of biomass productivity and biogas yield. energy conversion and management, 2015. 92: p. 137-142. [20] marzano, c.m.a.d.s., et al., biomethanation of the marine algae tetraselmis. international journal of solar energy, 1982. 1(4): p. 263-272. [21] kulkarni, m.g. and a.k. dalai, waste cooking oil an economical source for biodiesel: a review. industrial & engineering chemistry research, 2006. 45(9): p. 2901-2913. [22] quinn, j.c., et al., microalgae to biofuels: life cycle impacts of methane production of anaerobically digested lipid extracted algae. bioresource technology, 2014. 171: p. 37-43. [23] ravindran, r. and a.k. jaiswal, a comprehensive review on pre-treatment strategy for lignocellulosic food industry ali raza (et al.), current status of microalgae to produce biogas through pretreatment of lignocellulosic waste in the era of 21-century (pp. 99 114) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 112 waste: challenges and opportunities. bioresource technology, 2016. 199: p. 92-102. [24] teghammar, a., biogas production from lignocelluloses: pretreatment, substrate characterization, co-digestion and economic evaluation. 2013, chalmers tekniska högskola. [25] karlsson, h., et al., ethanol production in biorefineries using lignocellulosic feedstock–ghg performance, energy balance and implications of life cycle calculation methodology. journal of cleaner production, 2014. 83: p. 420-427. [26] miazek, k., et al., effect of lignocellulose related compounds on microalgae growth and product biosynthesis: a review. energies, 2014. 7(7): p. 4446-4481. [27] hu, q., et al., microalgal triacylglycerols as feedstocks for biofuel production: perspectives and advances. the plant journal, 2008. 54(4): p. 621-639. [28] taherzadeh, m.j. and k. karimi, pretreatment of lignocellulosic wastes to improve ethanol and biogas production: a review. international journal of molecular sciences, 2008. 9(9): p. 16211651. [29] cabral, j., e. ferreira, and m. mota, book of abstracts of the 2nd meeting of the institute for biotechnology and bioengineering. 2010. [30] teghammar, a., et al., techno-economic study of nmmo pretreatment and biogas production from forest residues. applied energy, 2014. 116: p. 125-133. [31] isikgor, f.h. and c.r. becer, lignocellulosic biomass: a sustainable platform for the production of bio-based chemicals and polymers. polymer chemistry, 2015. 6(25): p. 4497-4559. [32] vanholme, r., et al., lignin biosynthesis and structure. plant physiology, 2010. 153(3): p. 895-905. [33] qin, c., k. clarke, and k. li, interactive forces between lignin and cellulase as determined by atomic force microscopy. biotechnology for biofuels, 2014. 7(1): p. 65. [34] gonzález-fernández, c., et al., effect of organic loading rate on anaerobic digestion of thermally pretreated scenedesmus sp. biomass. bioresource technology, 2013. 129: p. 219-223. [35] ahmad, s., et al., prospects for pretreatment methods of lignocellulosic waste biomass for biogas enhancement: opportunities and challenges. biofuels 1– 20. htt p s. doi. org/10.1080/1759, 2017. 7269(2017): p. 1378. [36] howard, r., et al., lignocellulose biotechnology: issues of bioconversion and enzyme production. african journal of biotechnology, 2003. 2(12): p. 602619. [37] ahmad, s., et al., prospects for pretreatment methods of lignocellulosic waste biomass for biogas enhancement: opportunities and challenges. biofuels, 2018. 9(5): p. 575-594. [38] ziemiński, k., i. romanowska, and m. kowalska, enzymatic pretreatment of lignocellulosic wastes to improve biogas production. waste management, 2012. 32(6): p. 1131-1137. [39] kong, q.-x., et al., culture of microalgae chlamydomonas reinhardtii in wastewater for biomass feedstock production. applied biochemistry and biotechnology, 2010. 160(1): p. 9. [40] sharma, s., algae energy: a perspective on algae as a biogas source in nordic climate. 2017. [41] spolaore, p., et al., commercial applications of microalgae. j biosci bioeng, 2006. 101(2): p. 87-96. [42] varol, a. and a. ugurlu, biogas production from microalgae (spirulina platensis) in a two stage anaerobic system. waste and biomass valorization, 2016. 7(1): p. 193-200. [43] benhelal, e., et al., “aceme”: synthesis and characterization of reactive silica residues from two stage mineral carbonation process. environmental progress & sustainable energy, 2019. 38(3): p. e13066. [44] li, y., et al., characterization of a microalga chlorella sp. well adapted to highly concentrated municipal wastewater for nutrient removal and biodiesel production. bioresource technology, 2011. 102(8): p. 5138-5144. [45] xin, l., h. hong-ying, and y. jia, lipid accumulation and nutrient removal properties of a newly isolated freshwater microalga, scenedesmus sp. lx1, growing in secondary effluent. new biotechnology, 2010. 27(1): p. 59-63. [46] mussgnug, j.h., et al., microalgae as substrates for fermentative biogas production in a combined biorefinery concept. journal of biotechnology, 2010. 150(1): p. 51-56. ali raza (et al.), current status of microalgae to produce biogas through pretreatment of lignocellulosic waste in the era of 21-century (pp. 99 114) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 113 [47] batista, a.p., l. gouveia, and i.p.r. marques. scenedesmus obliquus: biogas production from residues of biodiesel/bioethanol extraction processes [resumo]. in 2nd international conference on algal biorefinery: a potential source of food, feed, biochemicals, biofuels and biofertilizers. 2014. [48] órpez, r., et al., growth of the microalga botryococcus braunii in secondarily treated sewage. desalination, 2009. 246(1-3): p. 625-630. [49] unpaprom, y., et al., cultivation of microalga botryococcus braunii using red nile tilapia effluent medium for biogas production. journal of ecology and environmental sciences, 2015. 3(2): p. 58-65. [50] neumann, p., et al., anaerobic codigestion of lipid-spent microalgae with waste activated sludge and glycerol in batch mode. international biodeterioration & biodegradation, 2015. 100: p. 85-88. [51] varel, v., t. chen, and a. hashimoto, thermophilic and mesophilic methane production from anaerobic degradation of the cyanobacterium spirulina maxima. resources, conservation and recycling, 1988. 1(1): p. 19-26. [52] bohutskyi, p., m.j. betenbaugh, and e.j. bouwer, the effects of alternative pretreatment strategies on anaerobic digestion and methane production from different algal strains. bioresource technology, 2014. 155: p. 366-372. [53] newsted, j.l., effect of light, temperature, and ph on the accumulation of phenol by selenastrum capricornutum, a green alga. ecotoxicology and environmental safety, 2004. 59(2): p. 237-243. [54] munir, n., et al., optimization of growth conditions of different algal strains and determination of their lipid contents. j anim plant sci, 2015. 25(2): p. 546-553. [55] converti, a., et al., effect of temperature and nitrogen concentration on the growth and lipid content of nannochloropsis oculata and chlorella vulgaris for biodiesel production. chemical engineering and processing: process intensification, 2009. 48(6): p. 11461151. [56] konopka, a. and t.d. brock, effect of temperature on blue-green algae (cyanobacteria) in lake mendota. appl. environ. microbiol., 1978. 36(4): p. 572576. [57] golueke, c.g., w.j. oswald, and h.b. gotaas, anaerobic digestion of algae. applied microbiology, 1957. 5(1): p. 47. [58] bajhaiya, a., et al., algal biodiesel the next generation biofuel for india. asian j. exp. biol. sci, 2010. 4: p. 728-739. [59] cerón garcí, m.c., et al., mixotrophic growth of phaeodactylum tricornutum on glycerol: growth rate and fatty acid profile. journal of applied phycology, 2000. 12(3): p. 239-248. [60] janssen, m., et al., specific growth rate of chlamydomonas reinhardtii and chlorella sorokiniana under medium duration light/dark cycles: 13–87 s. journal of biotechnology, 1999. 70(1-3): p. 323-333. [61] bhatnagar, a., et al., chlorella minutissima—a promising fuel alga for cultivation in municipal wastewaters. applied biochemistry and biotechnology, 2010. 161(1-8): p. 523536. [62] chen, f., high cell density culture of microalgae in heterotrophic growth. trends in biotechnology, 1996. 14(11): p. 421-426. [63] hasunuma, t., et al., development of a gin11/frt-based multiple-gene integration technique affording inhibitortolerant, hemicellulolytic, xyloseutilizing abilities to industrial saccharomyces cerevisiaestrains for ethanol production from undetoxified lignocellulosic hemicelluloses. microbial cell factories, 2014. 13(1): p. 145. [64] wi, s.g., et al., lignocellulose conversion for biofuel: a new pretreatment greatly improves downstream biocatalytic hydrolysis of various lignocellulosic materials. biotechnology for biofuels, 2015. 8(1): p. 228. [65] sakai, s., et al., effect of lignocellulosederived inhibitors on growth of and ethanol production by growth-arrested corynebacterium glutamicum r. appl. environ. microbiol., 2007. 73(7): p. 2349-2353. [66] jönsson, l.j., b. alriksson, and n.-o. nilvebrant, bioconversion of lignocellulose: inhibitors and detoxification. biotechnology for biofuels, 2013. 6(1): p. 16. [67] karlsson, a., et al., improvement of the biogas production process: explorative ali raza (et al.), current status of microalgae to produce biogas through pretreatment of lignocellulosic waste in the era of 21-century (pp. 99 114) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 114 project (ep1). 2014, linköping university electronic press. [68] makarevičienė, v., et al., performance and emission characteristics of diesel fuel containing microalgae oil methyl esters. fuel, 2014. 120: p. 233-239. [69] prajapati, s.k., et al., enhanced methane production from algal biomass through short duration enzymatic pretreatment and codigestion with carbon rich waste. rsc advances, 2015. 5(82): p. 6717567183. [70] hossain, a.s., et al., biodiesel fuel production from algae as renewable energy. american journal of biochemistry and biotechnology, 2008. 4(3): p. 250-254. [71] ward, a., d. lewis, and f. green, anaerobic digestion of algae biomass: a review. algal research, 2014. 5: p. 204214. ali raza (et al.), current status of microalgae to produce biogas through pretreatment of lignocellulosic waste in the era of 21-century (pp. 99 114) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 115 format template vol. 3, no. 2 | july december 2020 sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 59 micro-grid stability improvement using static synchronous compensator assisted with battery energy storage system saqif imtiaz1, muhammad massab khan1, zubair yamin2, muhammad siddique1, ashfaq riaz1 abstract: integration of distributed generation (dg) with distribution network is essential for best utilization of renewable resources in better economics and clean environmental aspect. micro-grid (mg) is an aggregation of electrical loads and dgs. intermittencies of load variation has adverse effect on the voltage at the point of a common couple (pcc). it also prevents the restoring of mg power back to stable state, and voltage instability at pcc makes mg weak interconnection with distribution power grid1. in this article, placement of static synchronous compensator (statcom) assisted with battery energy storage system (bess) at pcc scheme is developed. statcom assisted with battery energy storage system (bess) provides instant real power and reactive power support for coupled mg with power grid to ensure voltage stability margin at pcc and it is effective in restoring power stability2,3. proposed scheme is implemented on a test system which is simulated in matlab-simulink. the obtained results verify the effectiveness of placing statcom assisted with bess at pcc. keywords: micro-grid (mg), distributed power generation (dg), load variation, voltage stability margin, point of common coupling (pcc), static synchronous compensator (statcom), battery energy storage system (bess), power support 1. introduction nowadays, power demand is growing in exponential fashion across the globe. power consumers expect continuous, reliable and efficient power from utilities. conventional power plants run on fossil fuels, which are less convenient in economic and environmental aspects4. this is due to the rapid depletion of natural resources and carbon emissions. co2 contributes greatly to global warming. for these reasons conventional resources are less preferable [1]. modern research is more focused on finding efficient ways for power 1 department of electrical engineering, nfc iet. multan, pakistan 2 department of electrical engineering, nust college of e&me. rawalpindi, pakistan corresponding author: zubbairyamin@gmail.com generation. this mainly includes exploitation of renewable energy resources (rers). throughout the world, great attention has given to these renewable resources for electric power generation purposes5 [2]. especially europe intends to switch its power sector from conventional to renewable resources completely [3]. for that purpose, they are focused on solar, wind, biogas, geothermal, wave energy, ocean thermal energy (otec) and biomass. the concept of distribution generation (dg) system is used to integrate rers in the power system13. renewable energy resources saqif imtiaz (et al.), micro-grid stability improvement using static synchronous compensator assisted with battery energy storage system (pp. 59 72) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 60 are integrated at distribution level to avoid transmission network losses [4]. independently operating solar, wind, micro hydal, biomass, tidal units can be used as dgs [5]. micro-grid comprises dgs and local consumer load overcomes the deficiencies of dgs like randomness and intermittency [6]. it also links the entire dg network to the main power stream. however, this mg integration creates several operational challenges for the power system in both grids connected mode and islanded mode [7]. these days power utilities encounter voltage instability and lower power factor issues due to rapid increase in domestic and industrial loads worldwide6. the main target of utilities is to fulfill consumer demands reliably and efficiently. it also means that the consumer gets continuous supply of highquality power at economical rates. previous research revealed that about 13% of the generated power is wasted in terms of power losses in a line7. expansion of the distribution network requires supplementary complexity and proper maintenance of the power system8. abnormality due to both high and low voltages always contributes in the deterioration of power instruments, therefore always voltage stability9 is required at the customer’s end. sudden load variation of heavy inductive loads in power system causes voltage drop, voltage instability, power losses and increase in power energy cost10. when reactive power lower voltage stability current value is increased to adjust the power supplied, so more consumed reactive power is the major reason for the voltage drop in distribution networks11 [8]–[10]. to mitigate losses and improve voltage profile different compensation devices are used such as capacitor banks, voltage regulators, on load tap changers (oltcs) in widespread distribution networks. there is high energy demand on the distribution grid causes reduction in supply voltages from the grid to end-users12,13. static var compensator (svc) is a flexible ac transmission system (facts) device for voltage regulation to minimize power losses. svc is a thyristor control reactor device that absorb/supply the reactive power from/into the system13. the dgs are integrated with the distribution system to meet the energy demand and minimize voltage variations, which affects the performance of oltcs and the switchedcapacitor of the system [11]. svc and statcom is used for reactive power reserve management in ieee 9 and ieee 14 bus system14 [12]. the selection of suitable size and location for facts devices is a big issue that needs to be resolved. different optimization techniques and search algorithms are used in finding out the best location and sizing of facts controllers. optimizing algorithms like an artificial-bee colony, particle swarm optimization, novel-global harmony, search methodologies, and many other algorithms are widely used these days to solve the problem of acquiring the most candidate bus or line for placement of voltage controlling devices15 [13], [14]. in [15], the authors used a line stability indicator to identify the weakest lines in the distribution network for voltage profile improvement and mitigate power losses using the facts controller and shunt capacitor. review in [16], suggested that different techniques such as artificial-neural network, analytical, sensitivity-approaches, metaheuristic, combined meta-heuristic and sensitivity approaches are used to identify the optimum location and sizing of distribution static synchronous compensator (dsatcom) for mitigating voltage deviations, reducing power loss and voltage stability of distribution system network16. the thyristor control circuit for svc is proposed for power factor correction and voltage improvement at static and dynamic loads conditions. results of the measured power factor and voltage from software and hardware were compared17 [17]. to reduce voltage oscillations and power losses, dgs and svc are integrated into the distribution network in [18]. revamp voltage stability indicator is deployed to investigate the weakest bus on the power system in the short computational-time. the designed methodology is implemented on a 14-bus system using etap software18. in [19], authors saqif imtiaz (et al.), micro-grid stability improvement using static synchronous compensator assisted with battery energy storage system (pp. 59 72) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 61 develop a global attainment topology to solve the problem of multi-objective optimization. capacitor banks and svcs are correlated with dgs in the distribution system to eliminate voltage variations and reducing real power losses. the maximum hosting capacity of the distribution system for renewable energy based distributed generators are discussed in [20]. here a strategy based on the operation of robust on load tap changer and svc is proposed, which considers uncertainties in both load consumption and power generation from dgs. it was tested and verified on the ieee 33-bus distribution system19,20. in [21], authors developed mix integer linear program (milp) to achieve the optimum location of static var compensators (svcs) to maximize hosting-capacity of pv based dg. the objective of milp is to maintain the voltage stability and invested cost on svcs21. voltage stabilization and reactive power flow of statcom in a microgrid are studied in [22]. a detailed analysis is carried out on control of reactive power flow in different scenarios to meet the grid requirements. optimal sizing and placement of capacitors in the radial distribution system for enhancing voltage profile and reduction in power losses are addressed in [23]. this approach is carried out in two stages. in the first stage loss, sensitivity analysis is performed for the optimal location for capacitor and in the second stage, ant colony optimization algorithm is examined for optimum size and location of the capacitor in the distribution network while minimizing the cost and energy losses at the same time. results from 34-bus and 85-bus radial distribution systems support the integrity of the proposed strategy22, in article [24], the authors used voltage stability index (vsi) for identification of the most critical bus on the distribution power network for the installation of distributed generation. optimum dg size is selected by the genetic algorithm so that the power quality and voltage profile is improved. the proposed methodology is tested on ieee 33 bus and ieee 69 bus distribution system23. in [25], voltage fluctuations in the output of a hybrid microgrid based on wind and solar energy are compensated by the utilization of statcom. in this way, the stable operating limits of this hybrid microgrid was increased. the pi controllers of the statcom were optimized by using bacteria foraging and genetic algorithms, thus achieving a better response in terms of voltage stability in the presence of the intermittent nature of windsolar hybrid microgrid. results from the conventional pi controller and other suggested optimized algorithms in statcom were compared to demonstrate the efficiency of the proposed methodology25. a detailed comparison of svc and statcom for transient voltage stability in dfig based wind farm is presented in [26]. this research work proposed that statcom even with low capacity as compared to the svc is more reliable and cost-effective. that’s because it provides reactive power for voltage stability at much faster rates in contrast to the svc. a novel model based on a voltage source converter with a battery energy storage system that provides reactive power support to the distribution system for voltage profile enhancement and load leveling is proposed in24 [27]. issues related to the integration of microgrid with the traditional grid for smooth operation in grid-connected mode is presented in [28]. fluctuations in the load curve cause voltage instability at the point of the common couple. a stability management controller is designed and tested for stabilizing the voltages at the point of integration to overcome interconnection issues. this controller helped in securing the voltage at the interconnection25. this work on micro-grid stability improvement using statcom with assisted bess is a new contribution in the existing literature by taking these factors simultaneously as; • voltage stability at point of integration • active power and reactive power management • restoring power stability of micro-grid1 this article deals with the problems of voltage instability at the point of common coupling (pcc) and power restoring of microgrid when it faces high intermittencies of load saqif imtiaz (et al.), micro-grid stability improvement using static synchronous compensator assisted with battery energy storage system (pp. 59 72) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 62 27 variation at pcc26. classification of this paper is divided into five different sections. in section 2, mathematical formulation of statcom is discussed. proposed algorithm for operation of statcom with bess at point of common coupling (pcc) is discussed to achieve stability margin for micro-grid in section 3. section 4 explains about single line diagram and results of the early stated problem. finally, concluding remarks and future direction of this work has been discussed in section 5. 2. mathematical formulaiton for maximum power harvesting from the wind, a mathematical model of the wind turbine is presented. all essential parameters have been calculated by precisely considering wind speed, the angular speed of turbine blades, maximum allowed angle of rotor blades, temperature and pressure of wind, and other limiting constraints. after that control scheme of statcom for transient voltage stability and intelligent reactive and active power dispatch is discussed. 2.1. mathematical modelling of wind turbine the mechanical power that turbine units extract from wind is given in eq (1) 𝑃𝑤 = 1 2 𝐴𝜌𝑢𝑤(𝑢𝑢 2 − 𝑢𝑑 2 ) (1) where ‘uu’ is the velocity of upstream wind at the point where it enters the rotor blades and ‘ud’ is velocity of downstream wind at the exit of rotor blades. using mass flow rate, we can write (1) as (2), 𝐴𝜌𝑢𝑤 = 𝐴𝜌(𝑢𝑢 − 𝑢𝑑 ) 2 (2) where ‘uw ’ is the mean of velocity at the entrance and exit of blades. from the manipulation of eq (1) we will get (3), 𝑃𝑤 = 𝐴𝜌(𝑢𝑢 2 − 𝑢𝑑 2 ) 2 (𝑢𝑢 + 𝑢𝑑 ) 2 𝑃𝑤 = 1 2 [𝐴𝜌 { 𝑢𝑢 2 (𝑢𝑢 2 − 𝑢𝑑 2 )) + 𝑢𝑑 2 (𝑢𝑢 2 − 𝑢𝑑 2 )}] 𝑃𝑤 = [𝐴𝜌𝑢𝑢 3 { 1 + 𝑢𝑑 𝑢𝑢 − ( 𝑢𝑑 𝑢𝑢 ) 2 − ( 𝑢𝑑 𝑢𝑢 ) 3 2 }] 𝑃𝑤 = 1 2 𝐴𝜌𝑢𝑢 3 𝐶𝑃𝑢 (3) 𝐶𝑃𝑢 = 1 + 𝑢𝑑 𝑢𝑢 − ( 𝑢𝑑 𝑢𝑢 ) 2 − ( 𝑢𝑑 𝑢𝑢 ) 3 2 (4) in eq (4) ‘cpu’ is the power coefficient. it basically represents the portion of up-stream wind that is harvested by blades. moreover, the word “rotor efficiency” is extensively used for this. ‘cpu ’ is not a fixed value its varying value relies on the “tip speed ratio”, which is the ratio of ‘ud’ and ‘uu’ of turbine. 𝜆 = 𝑢𝑑 𝑢𝑢 (5) blade tip ratio ‘λ’ can also be found in m/s2 from eq (6), 𝜆 = 𝑟 × 𝑤𝑇 𝑢𝑤 (6) where uw = wind speed, wt = angular speed of the turbine, r = radius of the turbine. from eq (4) and (5) we get ( 7), 𝐶𝑃 = (1 − 𝜆2 )(1 + 𝜆) 2 (7) for the purpose of finding maximum value of ‘cp’, we need to take differential of eq (7) w.r.t ‘λ’ and put the entire equation equal to zero. that yields λ = −1, 1/3 from which only λ =1/3, yields maximum value of ‘cp’ (that is cp = 16/27). according to the betz limit wind turbine can only harvest 59.3% of the total kinetic energy from wind (cpmax = 0.59). in spite of everything wind turbines can’t operate at this limit in real world. saqif imtiaz (et al.), micro-grid stability improvement using static synchronous compensator assisted with battery energy storage system (pp. 59 72) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 63 𝜌 = 𝑃 𝑇𝑟𝑔 (8) 𝑃 = 𝜌𝑟𝑔 𝑇 (9) where ‘p’ is pressure, ‘t ’ is temperature and ‘rg is the gas constant. another important factor is altitude, since the pressure and temperature greatly vary with height, which in turn affects the density of air. after considering height in analysis we get relation for stp (standard temperature and pressure) in eq (10). 𝜌 = 𝜌0𝑒 −0.297𝐻 3048 (10) where ‘h’ is the elevation. eq (11) rotor efficiency in terms of pitch angle and tip speed ratio as suggested by bose and anderson [29] is 𝐶𝑃 = (𝜆 − 5.6 − 0.022𝜃2)𝑒 −0.17𝜆 2 (11) where ‘λ’ is the turbine tip speed ratio given by λ=uw/wt , uw is wind speed in mph and wt is angular turbine speed in rads−1and ‘θ’ is pitch angle of blades. parameters of turbine units are given in table i. operating characteristics of wind turbine is shown in fig 1. table i: parameters of wind turbine units in mg2 2.2. statcom control scheme statcom is working in coordination with energy storage system, in such a way that rapid and consistent support of both reactive and active power is provided for stabilization of voltage profile at point of common coupling (pcc). for this purpose, the control strategy opted by the statcom is to somehow maintain the terminal voltages (vpcc). for this reason, the voltage is perceived at the pcc and is compared with the vr (reference voltage). the error between these two voltages (ve) is handled by controller. output parameters values induction generator class 6-pole squirrel cage inductance (rotor, stator) lr =0.1796 h, ls=0.1252 h frequency, rating, voltage f=60hz, p=3 mw×2 units, v=600v2 friction factor f (pu)=0.01 resistance (stator and rotor) rs=0.0485 ω, rr =0.0438 ω rated wind speed for igs 9m/s pitch angle θmax=50 degree fig. 1: operating characteristics of wind turbine. saqif imtiaz (et al.), micro-grid stability improvement using static synchronous compensator assisted with battery energy storage system (pp. 59 72) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 64 from the controller (imq ) governs the amount of amplitude of source current (reactive power component) to be generated by the statcom. the d-q axis model in stationary reference frame is used for the simplification of 3-phase calculations. the source voltages have two components direct/in-phase and quadrature. direct unit vectors are vx, vy & vz are 3-phase sinusoidal functions, which are obtained from dividing the va, vb & vc (terminal ac voltages) by their amplitude vm. quadrature unit vectors ux, uy & uz of these voltages are acquired from the in-phase vectors vx, vy & vz respectively. in order to regulate the statcom terminal voltages the amplitude of voltage vm is calculated from the instantaneous pcc voltages (va, vb & vc). the voltage error signal is then generated by comparing vm and vr . upon multiplication of quadrature unit vectors ux, uy & uz with the output from controller imq we get quadrature component of source currents ixq, iyq & izq . the dc voltages vdc of the super capacitor is detected and matched with reference dc voltages vdcr as a consequence of which vdce error voltage is generated. which is treated by another controller, output from which is imd. this imd controls the amplitude of the active component of statcom current. from the multiplication of this controller output imd with in-phase unit vectors vx, vy & vz, inphase components of the source current ixd, iyd & izd are obtained. the summation of inphase ixd, iyd, izd and quadrature ixq, iyq, izq current components yields the reference source currents ixqr, iyqr & izqr. that is compared with measured source current ix, iy , iz from pcc in a pwm (pulse width modulation) current controller to produce the switching signals for the voltage source converter (vsc) in statcom. the vsc in turn produces the reactive current in response which is either fed into the system or either absorbed from the system. the voltages at the pcc are va, vb & vc which are sensed, their amplitude is obtained from eq (12). 𝑉𝑚 = √ 2 3 (𝑉𝑎 2 + 𝑉𝑏 2 + 𝑉𝑐 2) (12) eq (13) provides in-phase unit vectors. 𝑣𝑥 = 𝑉𝑎 𝑉𝑚 , 𝑣𝑦 = 𝑉𝑏 𝑉𝑚 , 𝑣𝑧 = 𝑉𝑐 𝑉𝑚 (13) the quadrature unit vectors ux, uy , uz are derived from in-phase unit vectors vx, vy , vz are given in eq (14). 𝑢𝑥 = 𝑣𝑧 √(3) − 𝑣𝑦 √(3) 𝑢𝑦 = 𝑣𝑥 √3 2 + (𝑣𝑦 − 𝑣𝑧 ) 2√3 𝑢𝑧 = − 𝑣𝑥 √3 2 + (𝑣𝑦 − 𝑣𝑧 ) 2√3 (14) reference current of the statcom actually has two parts in-phase & quadrature component. their values are computed as follows. from the ‘ve’ voltage error between the ‘vm’ measured voltage (3-phase voltages from to pcc) and the ‘vr ’ reference voltage, quadrature component of the reference current is obtained. ‘ve’ at nth instant is provided in eq (15). 𝑉𝑒(𝑛) = 𝑉𝑟 − 𝑉𝑚(𝑛) (15) eq (16) shows the output of the controller at nth sampling instant 𝐼𝑚𝑞(𝑛) = 𝐼𝑚𝑞(𝑛−1) + 𝐾𝑖 𝑉𝑒(𝑛) + 𝐾𝑝{𝑉𝑒(𝑛) − 𝑉𝑒(𝑛−1)} (16) where ‘ki’ and ‘kp’ are integral & proportional gains of the controller. ‘ve(n)’ and ‘ve(n−1)’ are errors in voltages at nth and (n-1)th instant. ‘imq(n−1)’ is the amplitude of the quadrature component of source current at (n-1)th instant. the quadrature component of the reference current is presented in eq (17). 𝑖𝑥𝑞 = 𝐼𝑚𝑞 𝑢𝑥 , 𝑖𝑦𝑞 = 𝐼𝑚𝑞 𝑢𝑦, 𝑖𝑧𝑞 = 𝐼𝑚𝑞 𝑢𝑧 (17) saqif imtiaz (et al.), micro-grid stability improvement using static synchronous compensator assisted with battery energy storage system (pp. 59 72) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 65 for in-phase component of the reference current the error voltage at the dc-capacitor is provided in eq (18). 𝑉𝑑𝑐𝑒(𝑛) = 𝑉𝑑𝑐𝑟 − 𝑉𝑑𝑐(𝑛) (18) where ‘vdcr ’ is the dc reference voltage that is fixed and ‘vdc(n)’ is the voltage that is measured across the super capacitor of statcom. eq (19) presents the output of the controller for controlling the dc bus voltages at nth sampling instant. 𝐼md (𝑛) = 𝐼md (𝑛−1) + 𝐾𝑖 𝑉dce(𝑛) + 𝐾𝑝{𝑉dee(𝑛) − 𝑉dce(𝑛−1)} (19) ‘imd’ is the active power component of source current. ‘ki’ & ‘kp’ are the integral and proportional gains of the controller respectively. in-phase reference current components are estimated in eq (20). 𝑖𝑥𝑑 = 𝐼𝑚𝑑 𝑣𝑥 , 𝑖𝑦𝑑 = 𝐼𝑚𝑑 𝑣𝑦 , 𝑖𝑧𝑑 = 𝐼𝑚𝑑 𝑣𝑧 (20) total reference current is given in eq (21) that goes to the pwm current controller is the sum of both quadrature & in-phase components. 𝑖𝑥 = 𝑖𝑥𝑑 + 𝑖𝑥𝑞 , 𝑖𝑦 = 𝑖𝑦𝑑 + 𝑖𝑦𝑞 , 𝑖𝑧 = 𝑖𝑧𝑑 + 𝑖𝑧𝑞 (21) now at pwm current controller the reference source currents and sensed source currents (from pcc) are compared. the output of which decides the switching pattern of igbts, by modifying the gate drive signals of igbt. eq (22) provides source error currents. 𝑖sxe = 𝑖𝑥 − 𝐼𝑎 , 𝑖sye = 𝑖𝑦 − 𝐼𝑏 , 𝑖sze = 𝑖𝑧 − 𝐼𝑐 (22) output of vsc produces reactive current in response which is fed into the system and absorbed from the system in case of excess reactive power on pcc. reactive power flow between statcom and pcc is given by eq. (23). where vpcc is pcc voltages, vstat is terminal voltages of statcom, x is total reactance due to interconnection equipment, φ is phase difference between vpcc and vstat. 𝑄 = 𝑉𝑝𝑐𝑐 𝑉𝑝𝑐𝑐 − 𝑉𝑠𝑡𝑎𝑡 cos 𝜙 𝑋 (23) dc side of statcom is coordinated with energy storage system so statcom also compensates for minor active power deficiencies. a power system that is supposed to drive the domestic, industrial and commercial loads is always designed to support the unsymmetrical as well as nonlinear loads. because the non-linear load will cause harmonics in the system, which will eventually degrade the voltages at bus bar. and due to unbalanced load unequal currents flow through 3-phases. statcom is capable of filtering such harmonics & balancing the unsymmetrical loads [30]. 3. the proposed algorithm joint strategy of statcom with battery bank charging for the stability improvement of micro-grid is shown in fig. 2 step 1: evaluation of voltage variations at point of integration bus (vpcc) are initialed and there are three possible outcomes for vpcc are obtained. step 2: if vpcc variations are lie within defined limits, then vpcc will equal to reference voltage (vref) and hence power delivered to the load. step 3: as per the conditions of voltage deviations, if vpcc is less than (vref) reveals that micro-grid (mg) has voltage instability concerns at pint of common coupling (pcc) bus. mg suffering under voltage at condition at pcc bus. in order to ensure voltage stability statcom used dc side battery bank provide instant support of reactive and active power support. if battery bank charging level is low statcom control managed to charge it through power grid and also used utility grid for backup power reserve for voltage stability. saqif imtiaz (et al.), micro-grid stability improvement using static synchronous compensator assisted with battery energy storage system (pp. 59 72) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 66 fig. 2: proposed joint strategy of statcom with battery energy storage system (bess) for stability improvement of micro-grid saqif imtiaz (et al.), micro-grid stability improvement using static synchronous compensator assisted with battery energy storage system (pp. 59 72) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 67 step 4: as per the conditions of voltage deviations, if vpcc is greater than (vref) reveals that micro-grid (mg) has voltage instability concerns at pint of common coupling (pcc) bus. mg suffering over voltage condition at pcc bus which is mostly unlikely event. in order to ensure voltage stability statcom control used its inductive mode of switches in order to absorb excessive available reactive power and hence reduce reactive power in mg system. if battery bank charging level is low statcom control managed to charge it through power grid and also used utility grid for backup power reserve for voltage stability. table ii: buses and loads input parameters for micro-grid2 step 5: when the voltage at pcc bus close to its defined reference value, then power will be delivered reliably. 4. simulation results and discussion a single line diagram of micro-grid distributed generation system is shown in fig. 3. wind power-assisted distributed generators in microgrid has induction generators that are unable to provide instant reactive power support toward regular load intermittencies. wind turbine units have a total rating of 6 mw and a diesel generator rating of 4 mw. intermittencies of load variations at microgrid causes voltage instability at pcc. so, the interconnection of micro-grid and conventional grid becomes weak and power restoring of micro-grid for stable power generation becomes major challenge. table 2 shows bus names, nominal voltage of buses and rating of loads attached to corresponding buses. load variation at pcc are between 8 mva to 15 mva3,4. in this article, the proposed statcom assisted battery energy storage system scheme is developed, which is integrated at pcc as shown in fig. 3. fig. 4, shows high intermittencies of inductive load variations at the pcc of the micro-grid distribution system. during these events of load variations microgrid control system is unable to provide support for the mg to restore power stability for stable power generation. in fig. 4, at 1.5s to 1.68s mg is struggling to regain power stability and continues to smooth power generation, but at 1.9s mg completely lost power stability and shuts down. in fig. 5, regardless of heavy inductive load switching on feeders at 1.5s to 1.68s, mg survives to restore power stability and, continues smooth power delivery, due to the newly incorporated developed scheme at the mg distribution system. buses voltage (kv) load (kva) b1 69 b2 69 b3 13.8 b4 13.8 b5 13.8 b6 13.8 b7 0.48 6000 b8 0.48 6000 b9 13.8 b10 13.8 b11 0.48 1802.8 b12 0.48 3000 b13 0.6 b14 13.8 b15 0.48 1500 b16 13.8 b17 0.48 1400 pcc 13.8 saqif imtiaz (et al.), micro-grid stability improvement using static synchronous compensator assisted with battery energy storage system (pp. 59 72) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 68 fig. 3: single line diagram of microgrid. fig. 4: micro-grid (mg) lost to restore power stability without statcom assisted battery energy storage system (bess) saqif imtiaz (et al.), micro-grid stability improvement using static synchronous compensator assisted with battery energy storage system (pp. 59 72) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 69 fig. 5: micro-grid (mg) restore power stability with statcom assisted battery energy storage system ( bess). in fig. 6, due to heavy inductive load switching at the micro-grid distribution system, voltage stability at pcc bus greatly affected and major voltage stability concerns can be seen. in fig. 6, at 1.5s to 1.68s undervoltage instability is more prominent. but with the use of statcom assisted with bess developed scheme in mg, it is seen at 1.5s s to 1.68s of voltage graph in fig. 7. mg achieved voltage stability margin affectively. micro-grid restores power stability and voltage stability by the utilization of new developed statcom assisted with battery energy storage system (bss) scheme. this scheme manages power support for mg. active power and reactive support maintain the mg to regain stability. in fig. 8, 1.5s to 5s graph show statocom assisted with bess provides instant reactive power support for micro-grid. fig. 6: voltage instability without statcom assisted bees saqif imtiaz (et al.), micro-grid stability improvement using static synchronous compensator assisted with battery energy storage system (pp. 59 72) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 70 fig 7: voltage stability with statcom assisted bees fig 8: power management of statcom assisted bees 5. conclusion and future research in this article, a proposed scheme of placing statcom assisted with battery energy storage system (bess) at point of common coupling (pcc), had developed for restoring power stability and improving voltage stability at pcc of wind-assisted micro-grid coupled with the power grid. high intermittencies of load variation at pcc of the micro-grid (mg), was a major concern, as it causes problems of voltage instability and restoring stable power in integrated microgrid. placed statcom assisted battery energy storage system (bess) at pcc manages real and reactive power support during intermittencies of load variation to sort out voltage stability and power restoring concerns of mg. furthermore, in the future, the placement of a unified power flow controller (upfc) can be used to improve the saqif imtiaz (et al.), micro-grid stability improvement using static synchronous compensator assisted with battery energy storage system (pp. 59 72) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 71 stability issues of the micro-grid integrated power grid. references [1] a. b. rao and e. s. rubin, “a technical, economic, and environmental assessment of amine-based co2 capture technology for power plant greenhouse gas control,” environmental science & technology, vol. 36, no. 20, pp. 4467–4475, 2002. [2] n. panwar, s. kaushik, and s. kothari, “role of renewable energy sources in environmental protection: a review,” renewable and sustainable energy reviews, vol. 15, no. 3, pp. 1513–1524, 2011. [3] a. zervos, c. lins, and j. muth, rethinking 2050: a 100% renewable energy vision for the european union. erec, 2010. [4] a. a. bayod-ru j́ula, “future development of the electricity systems with distributed generation,” energy, vol. 34, no. 3, pp. 377–383, 2009. [5] j. p. lopes, n. hatziargyriou, j. mutale, p. djapic, and n. jenkins, “integrating distributed generation into electric power systems: a review of drivers, challenges and opportunities,” electric power systems research, vol. 77, no. 9, pp. 1189–1203, 2007. [6] c. wang, j. yan, c. marnay, n. djilali, e. dahlquist, j. wu, and h. jia, “distributed energy and microgrids (dem),” 2018. [7] p. basak, s. chowdhury, s. h. nee dey, and s. chowdhury, “a literature review on integration of distributed energy resources in the perspective of control, protection and stability of microgrid,” renewable and sustainable energy reviews, vol. 16, no. 8, pp. 5545–5556, 2012. [8] b. tamimi and c. a. can˜izares, “modeling and application of hybrid power flow controller in distribution systems,” ieee transactions on power delivery, vol. 33, no. 6, pp. 2673–2682, 2018. [9] t. manglani and y. shishodia, “voltage profile improvement in radial distribution system using plant growth simulation algorithm.” [10] s. jalilzadeh and s. golchin, “voltage flicker parameters estimation usingshuffled frog leaping algorithm (sfla) andimperialistic competitive algorithm (ica),” international journal of computers & technology, vol. 15, no. 1, pp. 6373– 6378, 2016. [11] e. o. hasan, a. y. hatata, e. a. badran, and f. m. yossef, “optimal coordination of voltage control devices in distribution systems connected to distributed generations,” electrical engineering, vol. 101, no. 1, pp. 175–187, 2019. [12] k. c. sharma, s. sinha, and s. r. somanshu, “minimization of power loss in distribution system using svc and statcom,” 2017. [13] h. suyono, r. n. hasanah, and e. p. widyananda, “power system op timization of static var compensator using novel global harmony search method,” in accepted to be published in the international journal of electrical and electronic engineering & telecommunications (ijeetc), 2019. [14] s. h. kiran, s. s. dash, and c. subramani, “performance of two modified optimization techniques for power system voltage stability problems,” alexandria engineering journal, vol. 55, no. 3, pp. 2525– 2530, 2016. [15] h. saikumar et al., “voltage stability enhancement in radial distribution system by shunt capacitor and statcom,” in emerging research in electronics, computer science and technology. springer, 2019, pp. 1455–1468. [16] r. sirjani and a. r. jordehi, “optimal placement and sizing of distribution static compensator (d-statcom) in electric distribution networks: a review,” renewable and sustainable energy reviews, vol. 77, pp. 688–694, 2017. [17] m. y. pathak and j. jamnani, “design and hardware implementation of svc using thyristorised control for improving power factor and voltage profile of inductive loads,” in 2016 ieee 6th international conference on power systems (icps). ieee, 2016, pp. 1–6. [18] a. rath, s. r. ghatak, and p. goyal, “optimal allocation of distributed generation (dgs) and static var compensator (svc) in a power system using revamp voltage stability indicator,” in 2016 national power systems conference (npsc). ieee, 2016, pp. 1–6. [19] v. asgharian and v. i. genc, “multiobjective optimization for voltage saqif imtiaz (et al.), micro-grid stability improvement using static synchronous compensator assisted with battery energy storage system (pp. 59 72) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 72 regulation in distribution systems with distributed generators,” in 2016 ieee electrical power and energy conference (epec). ieee, 2016, pp. 1–6. [20] s. wang, s. chen, l. ge, and l. wu, “distributed generation hosting capacity evaluation for distribution systems considering the robust optimal operation of oltc and svc,” ieee transactions on sustainable energy, vol. 7, no. 3, pp. 1111–1123, 2016. [21] x. xu, z. xu, x. lyu, and j. li, “optimal svc placement for max imizing photovoltaic hosting capacity in distribution network,” ifac papersonline, vol. 51, no. 28, pp. 356– 361, 2018. [22] wang, qi, bin wang, wanwan xu, and jiapan xu. "research on statcom for reactive power flow control and voltage stability in microgrid." in 2018 13th ieee conference on industrial electronics and applications (iciea), pp. 2474-2479. ieee, 2018. [23] a. a. a. el-ela, r. a. el-sehiemy, a.-m. kinawy, and m. t. mouwafi, “optimal capacitor placement in distribution systems for power loss reduction and voltage profile improvement,” iet generation, transmission & distribution, vol. 10, no. 5, pp. 1209– 1221, 2016. [24] a. aravinth, v. a. vatul, k. narayanan, k. muthukumar, and t. senjyu, “a multiobjective framework to improve voltage stability in a distribution network,” international journal of emerging electric power systems, vol. 20, no. 1, 2019. [25] bakir, hale, and ahmet afsin kulaksiz. "modelling and voltage control of the solar-wind hybrid micro-grid with optimized statcom using ga and bfa." engineering science and technology, an international journal 23, no. 3 (2020): 576-584. [26] qi, jun, wenbin zhao, and xiaoyan bian. "comparative study of svc and statcom reactive power compensation for prosumer microgrids with dfig-based wind farm integration." ieee access (2020). [27] h. mehrjerdi, “simultaneous load leveling and voltage profile improve ment in distribution networks by optimal battery storage planning,” energy, 2019. [28] s. imtiaz, m. w. altaf, a. riaz, m. n. naz, m. k. bhatti, and r. g. hassan, “intermittent wind energy assisted micro-grid stability enhancement using security index currents,” in 2019 15th international conference on emerging technologies (icet). ieee, 2019, pp. 1–6. [29] a. w. manyonge, r. ochieng, f. onyango, and j. shichikha, “mathe matical modelling of wind turbine in a wind energy conversion system: power coefficient analysis,” applied mathematical sciences, vol. 6, no. 91, pp. 4527–4536, 2012. [30] ul-haq, azhar, zubair yamin, saifullah awan, and almas ajum. "frequency control of seig based microgrid during transition from grid connected to island mode." in 2020 9th international conference on industrial technology and management (icitm), pp. 234-238. ieee, 2020. 2. orientation detection of unequally spaced complexed grounding grids using transient electromagnetic method vol. 4, no. 2 | july – december 2021 sjet | p-issn: 2616-7069 |e-issn: 2617-3115 | vol. 4 no. 2 july – december 2021 18 orientation detection of unequally spaced complexed grounding grids using transient electromagnetic method usman zia saleem1, safdar raza1, inzamam ul haq2, muhammad bilal ashraf1 abstract: configuration of grounding grid is required for all currently proposed fault diagnosing methods of grounding grid if the configuration is unknown then grounding grid configuration detection techniques are applied and all of these latest techniques further requires the oriented angle at which the grid is laid and if the orientation of the grid is unknown or incorrect then the calculated configuration will be misleading and incorrect and we will fail to diagnose the grounding grid fault. in this paper transient electromagnetic method approach is used for orientation detection of unequally spaced grounding grids which are categorized as complexed grids further classified as unequally spaced grounding grids with diagonal element at larger mesh, smaller mesh or in both of these meshes. in tem method equivalent resistivities and magnetic field intensities are found at eight different points in a circular path of constant radius r to determine the size of meshes and the presence of conductors whether diagonal or not diagonal. model designing and simulations are performed using comsol multiphysics 5.4 software, values of magnetic field intensities and emf are derived from comsol multiphysics 5.4 software and the emf values are further called in a matlab code to run through number of mathematical formulations and equivalent resistivity is obtained for all desired points. obtained values of equivalent resistivity and magnetic field intensities verifies the effectiveness of the proposed approach for orientation detection of complexed grounding grid. keywords: equivalent resistivity, grounding grid, magnetic field intensity, orientation detection, transient electromagnetic method 1. introduction grounding system provides alternate route to the high flowing currents due to any risk of fault by sinking high currents through earth before the fault gets worst in form of electrical shock or hazardous fire. grounding means low resistive path between any desired electrical equipment and the ground. grounding is achieved by properly connecting the electrical equipment through cable into the ground using 1 department of electrical engineering, nfc institute of engineering & technology, multan, punjab, pakistan 2 state key laboratory of power transmission equipment & system security and new technology, chongqing university, chongqing 400044, china corresponding author: safdar.raza@nfciet.edu.pk relatively large extent of body to maximize the contact area with earth and keep the potential of connecting body to the potential of ground [1]. the depth of the grounding system depends upon the value of resistance it offers nec recommends that if the grounding rods are to be considers for grounding than 8 to 10 foot ground rod fails to meet the minimum resistance requirement mostly 30 foot provides us with 5 ohm or less resistance mailto:safdar.raza@nfciet.edu.pk u. z. saleem (et al.) orientation detection of unequally spaced complexed grounding grids using transient electromagnetic method (pp. 18 32) sukkur iba journal of emerging technologies sjet | vol. 4 no. 2 july – december 2021 19 which is feasible and the grounding resistance changes mostly in the first 20 foot. in a substation the grounding system consists of horizontally placed interlinked bare conductors with equal or unequal spacing within few meters apart, buried below the earth surface at about 0.7 to 1 meter depth. grounding system as discussed above provide finite resistance 1 ohm for large stations 1-5 ohm for distribution substations relatively small. this resistance is known as ground resistance. the potential of the grounding system is zero under normal conditions. under faulty condition when large amount passes into the earth then the ground potential of the faulty area rises with respect to the ground potential of remote earth away from the faulty area. so the potential rise of the specified part of the earth is known as gpr ground potential rise and it value increases with the severity of the fault and the increase in faulty current. mesh voltage and step voltage are two essential parameters which depends upon the value of ground resistance and gpr. the conductors present in the grounding grid system divide these voltages into the meshes present under the surface and the potential on the earth surface. mesh voltage is the maximum value of touch voltage offered within a specified surrounding. step voltage is the potential difference between the feet of a person standing near an energized grounding grid when the fault is occurring. human body offers non inductive impedance and purely resistive impedance for dc/ac voltage of 50 or 60 hz standard implemented worldwide. human body offers resistance from 500 to 5000 ohm but the average value is mostly considered as 1000 ohm [2]. the low impedance path is provided by installing grounding grid and can be found on all stages of electrical network from power plants to distribution units known as substations. the grounding grid is made of steel, cooper clad wires, galvanized steel and cooper steel alloys. these conductors are joint together and buried under the soil switched for lightning strokes and surges produced while switching high power loads [3, 4]. grounding grid’s efficiency depends upon the condition of conductors of grounding grid the conductors can be damaged due to corrosion due to presence of air gaps consisting oxygen and the moisture. both these elements begin the process of oxidation of conductors and damages the conductor current carrying capacity and can lead on to cut off the path entirely through breakdown of conductors. life estimation of grounding grid depends upon the overall size of grounding grid and also the precautionary preventive maintenances done over the regular recommended intervals [5] performance can be enhanced by reducing fault currents [6] or optimizing the overall configuration of grounding grid [7]. high faults currents in grounding grid can result in thermal and mechanical stresses so incase if we are unable to reduce the fault then we are required to design grounding grid to bear the offered high faulty current [8]. 2. related work transient analysis technique is quite old and have been using for grounding systems using different models such as transmission line models (tl models) [9-13]. circuit theory models [14, 15] and antenna theory models [16-21]. researches are also performed on comparative analysis between fig. 1. unequally spaced grounding grid with diagonal conductors. u. z. saleem (et al.) orientation detection of unequally spaced complexed grounding grids using transient electromagnetic method (pp. 18 32) sukkur iba journal of emerging technologies sjet | vol. 4 no. 2 july – december 2021 20 transmission line models and antenna theory models [20, 22]. circuit theory model is quite old and significantly simplified model due to which its accuracy is compromised also, we need to mention that surge propagation delay cannot be predicted using circuit theory model. tl transmission line method is feasible for finding surge propagation delay and computational cost of this transient analysis technique is less but tl method does not consider earth-air interface so ultimately the solution is compromised for some higher frequencies. antenna theory models are best for small grounding grid system as it the most accurate with high computational time and the complexity of this technique increases with the size of grounding grid. previously research work have been performed on finding grounding grid orientation through tem method but only for equally spaced and unequally spaced without diagonal and the recommended more work needs to be done for unequally spaced grounding grids with diagonal branches and this paper covers all the recommended research scopes [23]. a) fault diagnosis there are multiple research groups which are currently working on fault diagnosis of grounding grid. these research fields are mentioned below. i. electric network theory method. ii. electromagnetic field theory method. iii. electrochemical detection theory method. in electric network theory method we form nonlinear equations using surface potential difference and port resistance [24-28] these nonlinear equations can further used to diagnose grounding grid faults easily but this method requires the data regarding configuration of grounding grids. electrochemical methods can easily identify the corrosion of grounding grid conductors but the cannot find the breakage point of grounding grid [29]. transient electromagnetic method [30-32] is most feasible so far in this method ramp shaped current signal is injected he change in magnetic field produces secondary currents in the grounding conductor present below the ground level through which equivalent resistivity is calculated using inversion calculations these values of resistivity are used to identify faults in grounding grid. b) configuration configuration of grounding grid can be used as fault detection and also for improving the efficiency of the grounding grid. research group working on the relation between the efficiency and the changing configuration but the research group related to the configuration for fault diagnosis is not so active and creates a research gap [33]. first method is to record the magnetic intensity produced on the surface of the earth created due to the injection of sinusoidal current in the grounding mesh [34]. derivative methods are also quite famous for finding topology by applying 1st and 3rd derivatives on the magnetic field intensity recorded on the surface of the grid [35]. for specified angled branches the configuration can be found by taking circle and line derivatives of the magnetic flux density found on the surface of the earth [36]. transient electromagnetic method is the latest and most accurate method for finding the configuration of the grounding grid. c) orientation as we have already discussed that fault diagnosis is done accurately when the configuration of the grid is known but the configuration of the grounding grid is not always known and configuration of old grounding grids which have most probability of getting faulty are mostly unknown or lost so here the configuration detection techniques are applied all of the so far known techniques delivers inaccurate results if the grounding grid is installed at an angle to the plane of earth as we usually consider it parallel to the plane of earth for finding configuration so when the detected configuration is not accurate we will u. z. saleem (et al.) orientation detection of unequally spaced complexed grounding grids using transient electromagnetic method (pp. 18 32) sukkur iba journal of emerging technologies sjet | vol. 4 no. 2 july – december 2021 21 be unable to trace the faults in grounding grid as we may have gone on a wrong track initially ultimately getting nowhere near the fault so from the above discussion we can verify that accurate configuration of the grounding grid and the accurate location of faults can be diagnosed if we have the knowledge about at what angle the grid is laid. so far there is proposed method for orientation detection of grounding grid derivative method based novel techniques along with the concept of finding geometry of mesh to further find out the angle of the grounding grid [37]. in this method direct current is injected in to the grounding grid mesh and as a result the magnetic field density are recorded on the surface of the earth derivatives are take of these densities in a circular path starting from the center of a vertical conductor so all the adjacent branches are found in 360 degrees. the main drawback of the abovementioned technique is that noise may add in the generated magnetic fields densities of the grounding grid by interacting with the external electromagnetic fields of the nearby equipment. as we have discussed earlier the importance of the orientation detection of grounding grid. i propose a tem method for orientation detection of grounding grid so that we don’t have to waste time on soil excavation of entire grid despite a specified point where fault exists. when we manage to find the oriented angle of the grid we can then proceed further to detect its complete configuration or topology which was previously not known due to the mishandling if the diagrams or not following diagram while erection of grounding grid or changing the angle parameters last minute to overcome any physical challenge faced a that time. so, this methodology comes in handy whenever the angle of the grid is unknown or varies from the mentioned angle provided in manuals whenever the grid is not parallel to the earth’s plane. fig. 3. grounding grid installed at an angle to the station. 3. proposed methodology 3.1. transient electromagnetic method tem tem is mostly popular for geological exploration for onshore exploration and offshore exploration. exploration of minerals, oil, gas and ground water is performed and also being used for environmental mapping. water filled mining, tunnel designing [38-44]. the figure 4 is the schematic layout of a basic tem system which consists of two coils one of them is transmitter coil and one of them is receiver coil. transmitter coil also known as primary coil is injected with current pulse of ramp wave as a result magnetic field is produced when current ramp signal is switched fig. 2. grounding grid installed parallel to the station. u. z. saleem (et al.) orientation detection of unequally spaced complexed grounding grids using transient electromagnetic method (pp. 18 32) sukkur iba journal of emerging technologies sjet | vol. 4 no. 2 july – december 2021 22 off as a result during switching time an emf is produced in the surrounding conductor this stored emf further produced secondary magnetic field in the transmitter coil while the current signal is still switched off. fig 4. diagram of generalized transient electro magnetic method. the figure 5 shows the injected ramp current wave which has both on time and off time ramp signal are used to switch on and switch off the current during switching off time period due to changing value of decreasing current emf is induced in the opposite direction this emf is further discharged in form of magnetic field during off time of current signal. fig. 5. basic nomenclature and principles of the tem. figure 5 defines the working and principles of tem method. a) current signal injected in transmitter loop. b) emf induced in surrounding conductor. c) secondary magnetic field produced in receiver coil. 3.2. tem for grounding grid transmitter coil is placed 50 cm above the ground and made up with pure copper (copper selected from built-in materials of comsol) it is torus shaped having major radius of 0.15 m and minor radius of 0.02 m all along 360 degrees the transmitter coil is injected with 16a current pulse with wave form shown in the figure 6 and the receiver coil is supposed to be the center point of the coil at which simulation data during off and on time is extracted such as magnetic field intensities and emf with time step of 10 µs for 600 time samples during first 500 time steps the transmitter coil is on and energized with 16a current pulse and for last 100 time samples transmitter coil is off and it is the vital data that is extracted in form of text files for both magnetic field intensities and emf. the entire process is repeated for all the desired coordinates and the data is store in 8 different text files. magnetic field intensities of last 100 samples from 0.00501 sec to 0.006 sec are processed to calculate absolute average of all 100 values for each desired location. emf during off time of last 100 samples from 0.00501 sec to 0.006 sec are imported into ms excel spreadsheet and further these excel sheets are called in matlab code that are used in the equations for further finding equivalent resistivity for all desired 8 locations are evaluated. u. z. saleem (et al.) orientation detection of unequally spaced complexed grounding grids using transient electromagnetic method (pp. 18 32) sukkur iba journal of emerging technologies sjet | vol. 4 no. 2 july – december 2021 23 fig. 6. finalized input current source wave form 3.3. formulalation of apparent resistivity magnetic field intensities are produced in all directions along all axis due to eddy currents the magnetic field intensity along z axis which is coming out of the earth surface can be easily found using. 𝐻𝑧 = 𝐼 2𝑎 [ 3 √𝜋𝑢 𝑒−𝑢 + (1 − 3 2𝑢2 )𝑒𝑟𝑓(𝑢)] (1) u=θa, “a” is the radius of the transmitter coil loop, erf(u) is error function of u variable. by taking derivative with respect to u of equation (1) we will have e(t) 𝑑𝐻𝑧 𝑑𝑢 = 𝐸(𝑡) = 𝐼 𝜎𝑎3 [3𝑒𝑟𝑓(𝑢) − 2 √𝜋 𝑢(3 + 2𝑢2)𝑒−𝑢 2 ] (2) formula for calculating erf(u) is 𝑒𝑟𝑓(𝑢) = 2 √𝜋 ∫ 𝑒−𝑢 2 𝑢 0 𝑑𝑡 (3) error function gives us the value of probability for which if desired value is within the specified range. u is the parameter of transient magnetic field and is expressed as following 𝑢 = √ 𝜇𝑜𝜎𝑎 2 4𝑡 = 𝜃𝑎 (4) taking square of equation (4) will give us following equation. 𝑢2 = 𝜇𝑜𝜎𝑎 2 4𝑡 (5) rearranging the equation (5) for the value of conductivity (σ) we will get. 𝜎 = 4𝑢2𝑡 𝜇𝑜𝑎 2 (6) putting the value of conductivity in equation (2). 𝐸(𝑡) = 𝐼 4𝑢2𝑡 𝜇𝑜𝑎 2 𝑎 3 [3 × 𝑒𝑟𝑓(𝑢) − 2.0 √𝜋 × 𝑢 × (3.0 + 2 × 𝑢2) × 𝑒−𝑢 2 ] (7) 𝐸(𝑡) = 𝐼𝜇𝑜 4𝑢2𝑡𝑎 [3𝑒𝑟𝑓(𝑢) − 2 √𝜋 𝑢(3 + 2𝑢2)𝑒−𝑢 2 ] (8) 3𝑒𝑟𝑓(𝑢) − 2 √𝜋 𝑢(3 + 2𝑢2)𝑒−𝑢 2 − 𝐸(𝑡)4𝑢2𝑡𝑎 𝐼𝜇𝑜 = 0 (9) rewriting equation (9) as function of u. 𝐹(𝑢) = 3𝑒𝑟𝑓(𝑢) − 2 √𝜋 𝑢(3 + 2𝑢2)𝑒−𝑢 2 − 𝐸(𝑡)4𝑢2𝑡𝑎 𝐼𝜇𝑜 (10) as we know that conductivity and resistivity have inverse relation so 𝜌 = 1 𝜎 (11) putting the value of conductivity (σ) in equation (11) from equation (6) 𝜌(𝑡) = √ 𝜇𝑜𝑎 2 4𝑢2𝑡 (12) parameter “u” can be obtained by optimizing equation (10). apparent resistivity at any sampling time ti in terms of “u” can be expressed as 𝜌(𝑡𝑖) = √ 𝜇𝑜𝑎 2 4𝑢2𝑡𝑖 13 equation for finding vertical depth (d) of induced eddy currents. 𝑑 = 4 √𝜋 √ 𝑡𝜌 𝜇 14 equation for finding velocity (v) of induced eddy currents. u. z. saleem (et al.) orientation detection of unequally spaced complexed grounding grids using transient electromagnetic method (pp. 18 32) sukkur iba journal of emerging technologies sjet | vol. 4 no. 2 july – december 2021 24 𝑣 = 2 √𝜋 √ 𝜌 𝑡𝜇 15 equation for finding downward velocity (v) between two consecutive samples 𝑣 = 𝑑𝑖+1 − 𝑑𝑖 𝑡𝑖+1 − 𝑡𝑖 16 comparing equation (15) and equation (16) 𝑑𝑖+1 − 𝑑𝑖 𝑡𝑖+1 − 𝑡𝑖 = 2 √𝜋 √ 𝜌 𝑡𝜇 17 taking square of the above equation (𝑑𝑖+1 − 𝑑𝑖) 2 (𝑡𝑖+1 − 𝑡𝑖) 2 = 4𝜌 𝜋𝑡𝜇 18 rearranging the above equation (18) 𝜌𝑟 = (𝑑𝑖+1 − 𝑑𝑖) 2 (𝑡𝑖+1 − 𝑡𝑖) 2 ( 𝜋𝑡𝜇 4 ) 19 from equation (14) depth can be rewritten for two consecutive time samples ti and ti+1 𝑑𝑖+1 − 𝑑𝑖 = 4 √𝜋𝑢 (√𝑡𝑖+1𝜌𝑖+1 − √𝑡𝑖𝜌𝑖) 20 taking square of the above equation (20) (𝑑𝑖+1 − 𝑑𝑖) 2 = 16 𝜋𝜇 (√𝑡𝑖+1𝜌𝑖+1 − √𝑡𝑖𝜌𝑖) 2 21 putting equation (20) in equation (18) 𝜌𝑟 = 𝜋𝑡𝜇16 4𝜋𝜇 . (√𝑡𝑖+1𝜌𝑖+1 − √𝑡𝑖𝜌𝑖) 2 .( 1 (𝑡𝑖+1−𝑡𝑖) ) 2 22 rearranging above equation 𝜌𝑟 = 4𝑡. ( √𝑡𝑖+1𝜌𝑖+1 − √𝑡𝑖𝜌𝑖 (𝑡𝑖+1 − 𝑡𝑖) ) 2 23 here t is the average time of the consecutive samples can be expressed as 𝑡 = 𝑡𝑖+1 + 𝑡𝑖 2 24 equivalent resistivity ρr can be calculated by using equation (23) in equation (22) 𝜌𝑟 = 4. ( √𝑡𝑖+1𝜌𝑖+1 − √𝑡𝑖𝜌𝑖 (𝑡𝑖+1 − 𝑡𝑖) ) 2 . ( 𝑡𝑖+1 + 𝑡𝑖 2 ) 25 3.4. mathematicall modelling function expressed in equation (10) is the main function of the proposed research model. following 8 inputs are used in the proposed functions to get desired outputs. e = 2.718 i=transmitter current = 16amp vacuum permeability= = 4*pi*10^-7 h/m a=radius of transmitter loop = 0.15 m =conductivity of medium = 4.032*10^6 s/m t= sampling time = [0.00501:0.001:0.006] sec error function=𝑒𝑟𝑓(𝑢) = 2 √𝜋 ∫ 𝑒−𝑢 2𝑢 0 𝑑𝑡 magnetic permeability= 𝑢 = √ 𝜇𝑜𝜎𝑎 2 4𝑡 = 𝜃𝑎 following outputs are obtained as end results. apparent resistivity=𝜌(𝑡) = √ 𝜇𝑜𝑎 2 4𝑢2𝑡 apparent resistivity is the resistivity of any material that can be derived from above mentioned formula using vacuum / magnetic permeability, radius of transmitter loop at any specific single time sample t. equivalent resistivity= 𝜌𝑟 𝜌𝑟 = 4. ( √𝑡𝑖+1𝜌𝑖+1 − √𝑡𝑖𝜌𝑖 (𝑡𝑖+1 − 𝑡𝑖) ) 2 . ( 𝑡𝑖+1 + 𝑡𝑖 2 ) equivalent resistivity is the basically the equivalence of two apparent resistivities of consecutive time samples such as off 𝜌(𝑡), 𝜌(𝑡 + 1) and in the end average of these equivalent resitivities are calculated evaluated from all time samples. 4. results and discussions 4.1. simulaton model designing both of the figures below figure 7 and figure 8 both are the designed models of u. z. saleem (et al.) orientation detection of unequally spaced complexed grounding grids using transient electromagnetic method (pp. 18 32) sukkur iba journal of emerging technologies sjet | vol. 4 no. 2 july – december 2021 25 comsol multiphysics the two dimensional and 3-dimensional view of the model the workspace dimensions are also mentioned top most layer is for air and the bottom layer is for ground. ground layer (soil material is selected from minerals, rocks and soil section of material library in comsol) is square cube shaped 6 meter in length and 6 meter in width and the depth is 0.7 meters is set to be homogenous and its conductivity is set at 0.2 s/m and resistivity 5ω.m. air layer (air material imported from built-in materials of comsol) is also solid square cube 6 meters in length and 6 meters in width and 0.3 meter in depth having set with the properties of air. grounding grid mesh is buried 0.5 meters below he earth surface right in the middle having dimensions of 4x4 meter grid consists of two 1.5x2 meter loops and two 3.5x2 meter loops connected together it is made up with steel alloy asi 4340 imported from built in material list and having resistivity of 2.48 ×10−7 ω.m. the radius of the conductor is 10 cm. fig. 7. comsol multiphysics 2d model of unequally spaced mesh with smaller diagonal branch for simulation fig. 8. comsol multiphysics 3d model of unequally spaced mesh with smaller diagonal branch for simulation. 4.2. calculations of desired coordinates here all coordinates are calculated for which simulations will take place in a circular path of 1m in radius and having center at the joining point of all four meshes which are equally spaced and the coordinates will be (3,3) from the origin reference to model placement for simulation in comsol. so, by using the angles we can find out the x and y coordinates as following. coordinate c1 at θ1: θ1=00 radius of circle = r = 1 meter. 𝑥1 = 𝑟. 𝑐𝑜𝑠 𝜃1 = 1. 𝑐𝑜𝑠(0 𝑜) = 1 𝑦1 = 𝑟. 𝑠𝑖𝑛 𝜃1 = 1. 𝑠𝑖𝑛( 0 𝑜) = 0 𝑥0 = 3, 𝑦0 = 3, (𝑋1, 𝑌1) = (𝑥0 + 𝑥1, 𝑦0 + 𝑦1) = (3 + 1,3 + 0) 𝐶1 = (𝑋1, 𝑌1) = (4,3) coordinate c2 at θ2: θ2=450 radius of circle = r = 1 meter. 𝑥2 = 𝑟. 𝑐𝑜𝑠 𝜃2 = 1. 𝑐𝑜𝑠(45 𝑜) = 0.7071 𝑦2 = 𝑟. 𝑠𝑖𝑛 𝜃2 = 1. 𝑠𝑖𝑛( 45 𝑜) = 0.7071 𝑥0 = 3, 𝑦0 = 3, u. z. saleem (et al.) orientation detection of unequally spaced complexed grounding grids using transient electromagnetic method (pp. 18 32) sukkur iba journal of emerging technologies sjet | vol. 4 no. 2 july – december 2021 26 (𝑋2, 𝑌2) = (𝑥0 + 𝑥2, 𝑦0 + 𝑦2) = (3 + 0.7071,3 + 0.7071) 𝐶2 = (𝑋2, 𝑌2) = (3.7071,3.7071) coordinate c3 at θ3: θ3=900 radius of circle = r = 1 meter. 𝑥3 = 𝑟. 𝑐𝑜𝑠 𝜃3 = 1. 𝑐𝑜𝑠(90 𝑜) = 0 𝑦3 = 𝑟. 𝑠𝑖𝑛 𝜃3 = 1. 𝑠𝑖𝑛( 90 𝑜) = 1 𝑥0 = 3, 𝑦0 = 3 (𝑋3, 𝑌3) = (𝑥0 + 𝑥3, 𝑦0 + 𝑦3) = (3 + 0,3 + 1) 𝐶3 = (𝑋3, 𝑌3) = (3,4) coordinate c4 at θ4: θ4=1350 radius of circle = r = 1 meter. 𝑥4 = 𝑟. 𝑐𝑜𝑠 𝜃4 = 1. 𝑐𝑜𝑠(135 𝑜) = −0.7071 𝑦4 = 𝑟. 𝑠𝑖𝑛 𝜃4 = 1. 𝑠𝑖𝑛( 135 𝑜) = 0.7071 𝑥0 = 3, 𝑦0 = 3 (𝑋4, 𝑌4) = (𝑥0 + 𝑥4, 𝑦0 + 𝑦4) = (3 + (−0.7071), 3 + 0.7071) 𝐶4 = (𝑋4, 𝑌4) = (2.2929,3.7071) coordinate c5 at θ5: θ5=1800 radius of circle = r = 1 meter. 𝑥5 = 𝑟. 𝑐𝑜𝑠 𝜃5 = 1. 𝑐𝑜𝑠( 180 𝑜) = −1 𝑦5 = 𝑟. 𝑠𝑖𝑛 𝜃5 = 1. 𝑠𝑖𝑛( 180 𝑜) = 0 𝑥0 = 3, 𝑦0 = 3 (𝑋5, 𝑌5) = (𝑥0 + 𝑥5, 𝑦0 + 𝑦5) = (3 + (−1),3 + 0) 𝐶5 = (𝑋5, 𝑌5) = (2,3) coordinate c6 at θ6: θ6=2250 radius of circle = r = 1 meter. (𝑋6, 𝑌6) = (𝑥0 + 𝑥6, 𝑦0 + 𝑦6) = (3 + (−0.7071),3 + (−0.7071)) 𝐶6 = (𝑋6, 𝑌6) = (2.2929,2.2929) coordinate c7 at θ7: θ7=2700 radius of circle = r = 1 meter. 𝑥7 = 𝑟. 𝑐𝑜𝑠 𝜃7 = 1. 𝑐𝑜𝑠(270 𝑜) = 0 𝑦7 = 𝑟. 𝑠𝑖𝑛 𝜃7 = 1. 𝑠𝑖𝑛(270 𝑜) = −1 𝑥0 = 3, 𝑦0 = 3 (𝑋7, 𝑌7) = (𝑥0 + 𝑥7, 𝑦0 + 𝑦7) = (3 + (0), 3 + (−1)) 𝐶7 = (𝑋7, 𝑌7) = (3,2) coordinate c8 at θ8: θ8=3150 radius of circle = r = 1 meter. 𝑥8 = 𝑟. 𝑐𝑜𝑠 𝜃8 = 1. 𝑐𝑜𝑠(315 𝑜) = 0.7071 𝑦8 = 𝑟. 𝑠𝑖𝑛 𝜃8 = 1. 𝑠𝑖𝑛( 315 𝑜) = −0.7071 𝑥0 = 3, 𝑦0 = 3 (𝑋8, 𝑌8) = (𝑥0 + 𝑥7, 𝑦0 + 𝑦7) = (3 + 0.7071 + ,3 + (−0.7071)) 𝐶8 = (𝑋8, 𝑌8) = (3.7071,2.2929) 4.3. selected grounding grid models layouts basic layout of all the grounding grids is same with some minor changes such as the position of diagonal branches and the size of these diagonal branches and the quantity of these branches. all the proposed models are mentioned below each of them mentioned with their changes a) unequally spaced grounding grid with smaller diagonal branch. u. z. saleem (et al.) orientation detection of unequally spaced complexed grounding grids using transient electromagnetic method (pp. 18 32) sukkur iba journal of emerging technologies sjet | vol. 4 no. 2 july – december 2021 27 b) unequally spaced grounding grid with larger diagonal branch. c) unequally spaced grounding grid with both smaller and larger diagonal branches. in the figure 9 only one diagonal branch is present denoted by conductor s13 meeting the nodes 5 and 9 in the first mesh of the grid which is smaller in size located between the nodes 5,6,9 and 8. fig. 9. grounding grid layout of unequally spaced grounding grid with diagonal branch in the smaller mesh. in the figure 10 only one diagonal branch is present denoted by conductor s13 meeting the nodes 5 and 1 in the third mesh of the grid which is larger in size located between the nodes 1,2,5 and 4. fig. 10. grounding grid layout of unequally spaced grounding grid with diagonal branch in the larger mesh. in this model grid has both diagonals mentioned above both smaller and larger in same meshes 1st and 3rd. fig. 11. grounding grid layout of unequally spaced grounding grid with 2 diagonal branches in both smaller and larger mesh. 4.4. discussion on results of all the proposed models comparative graphs of all the results of the proposed models are given below for equivalent resistivity and magnetic field intensity. fig. 12. equivalent resistivity and magnetic field intensities comparative plot at all measuring 8 coordinates of unequally spaced grounding grid with diagonal branch in smaller mesh. u. z. saleem (et al.) orientation detection of unequally spaced complexed grounding grids using transient electromagnetic method (pp. 18 32) sukkur iba journal of emerging technologies sjet | vol. 4 no. 2 july – december 2021 28 fig. 13. equivalent resistivity and magnetic field intensities comparative plot at all measuring 8 coordinates of unequally spaced grounding grid with diagonal branch in larger mesh. fig. 14. equivalent resistivity and magnetic field intensities comparative plot at all measuring 8 coordinates of unequally spaced grounding grid with 2 diagonal branches in both smaller and larger mesh. numerical figures derived from the abovementioned graphs in figure 12, figure 13 and figure 14 of equivalent resistivities and magnetic field intensities which are shown in table format below it is much easier for interpretation and comparative analysis. this space is intentionally left blank to adjust tables on other column. table 1: average equivalent resistivities at all the specified coordinates of the experimented models. measuring coordinate average equivalent resistivity (ωm) unequally spaced mesh with smaller diagonal unequally spaced mesh with larger diagonal unequally spaced mesh with both smaller and larger diagonal c1 0.2758 0.2889 0.2758 c2 0.2982 0.2752 0.2982 c3 0.2736 0.2856 0.2736 c4 0.2933 0.2933 0.2933 c5 0.2955 0.2922 0.2922 c6 0.2944 0.2965 0.2965 c7 0.2851 0.2878 0.2878 c8 0.2752 0.2752 0.2752 table 2: average magnetic field intensities at all the specified coordinates of the experimented models. measuring coordinate average magnetic field intensity (a/m) unequally spaced mesh with smaller diagonal unequally spaced mesh with larger diagonal unequally spaced mesh with both smaller and larger diagonal c1 313.16 116.05 313.68 c2 205.06 326.81 200.92 c3 344.96 271.71 345.69 c4 90.3 91.02 92.43 c5 59.3 98.97 101.1 c6 78.38 48.77 48.77 c7 272.11 130.91 131.47 c8 325.17 329.16 330.47 coordinates c4 and c8 are identical in all three models so as a result they have same values for equivalent resistivity and magnetic field intensity for all three proposed models because these lies in the middle of the u. z. saleem (et al.) orientation detection of unequally spaced complexed grounding grids using transient electromagnetic method (pp. 18 32) sukkur iba journal of emerging technologies sjet | vol. 4 no. 2 july – december 2021 29 meshes where there are no diagonal branches in the middle of 2nd and 4th mesh here overall resistivity and magnetic field intensity is not affected by the diagonal branches in the neighboring meshes. c4 has low magnetic field intensity due to larger size mesh and low current flows so the equivalent resistivity is higher and c8 has higher magnetic field intensities due to smaller mesh and higher current flow so the equivalent resistivity will decrease. 1st model in figure 9 and the 3rd model in figure 11 both have identical 1st mesh here at c1 two currents flows i1 and i5 in case of first model both current are flowing through different sized meshes so both currents are not same and opposing each other so as a result significant net current flows which increases the mfi relatively to 2nd highest overall and minimize the equivalent resistivity. at coordinate c1 currents i1 and i5 in 2nd model (figure 10) are equal and opposite in direction due to non-presence of diagonal element so very low current flows and mfi is relatively smaller and equivalent resistivity is higher. similarly, at coordinate c2 currents i1 and i2 for 1 st and 3rd model are equal yet opposite in direction and nullify each other as a result very least current flows so we get higher equivalent resistivity and relatively lower mfi. c2 coordinate in 2 nd model figure 10 is in the middle of the smaller mesh with strong magnetic field and produces large eddy currents so we get higher magnetic field intensity and low equivalent resistivity. coordinate c3 has same results for 1 st and 3rd model because of same configuration currents i2 and i3 flowing through c3 are unequal and opposite due to presence of diagonal branch in smaller mesh and the net current is relatively higher because current flowing i2 is higher than the current i3 lower so some significant current flows as a result equivalent resistivity is lower and mfi is the highest. coordinate c3 in 2 nd model figure 10 will have moderate mfi and moderate equivalent resistivity coz of moderate current flowing through it i2 with lesser value and i1 with higher value opposing each other and net current is moderate. from coordinate c5 to so on the 2 nd model figure 10 is same as the 3rd model figure 11 so the output result of both models are approximately same, at c5 in 1 st model figure 10 there is no larger diagonal so it lies in between the larger meshes which are already flowing lesser currents i3 and i4 opposite to each other so nullifies each other and net current is the least of all as a result equivalent resistance is highest of all and the mfi is least of all the values of 1st model figure 9. c5 in 2 nd and 3rd model has a neighboring larger diagonal branch due to which in case of 2nd model figure 10 two currents are flowing from c5 i2 and i3, i3>i2 so some net current flows as a result of the opposition so equivalent resistance is relatively smaller and mfi is relatively larger than c4 but still less than c7. c6 coordinate in case of 1 st model figure 9 lies in almost at the middle of mesh no 3 the weak magnetic fields are produced due to the larger mesh size so lesser eddy currents are induced as a result larger value of equivalent resistivity but not the least and weaker mfi but still larger than c5. c6 for 2 nd and 3rd model are same and have almost same values as it lies almost on top of the large diagonal branch where in case of 2nd model i3 and i4 flowing opposite to each other and with exactly same values which are lesser due to larger diagonal branch size and net current is the least of all the others even considering all other models too so the equivalent resistivity is the highest of all the models and magnetic field intensity is the least of all the other models. c7 coordinate in case of 1 st model figure 9 correlates to c3 in 2 nd model figure 10 and have almost same values of equivalent u. z. saleem (et al.) orientation detection of unequally spaced complexed grounding grids using transient electromagnetic method (pp. 18 32) sukkur iba journal of emerging technologies sjet | vol. 4 no. 2 july – december 2021 30 resistivity and magnetic field intensities describer earlier. c7 coordinate in 2 nd model figure 10 and 3rd model figure 11 has same results due to same configuration in case of 2nd model figure 10 currents i4 and i5 are flowing from c7 both of these currents are not similar and opposite to each other due to which some net current flows which is lesser than the current of c7 in model no 1 and has a bit lesser magnetic field intensity and a bit higher equivalent resistivity than c7 in model no 1 5. conclusion and future scope starting from the scratch the physical position of a single grounding conductor leads onto finding the complete oriented angle of the grounding grid. magnetic field intensities in the middle of smaller loops are stronger than the middle of bigger loops and the equivalent resistivity in the middle of the smaller loops are greater than the equivalent resistivity at the middle of the bigger loops. diagonal elements at the middle of the loops increases the equivalent resistance and decreases the magnetic field intensity. conductor shared by the bigger loops have the least value of magnetic field intensity and highest value equivalent resistivity. diagonal branches and unequal sizes of loops results in unbalanced and unequal flowing currents. magnetic field intensity on the diagonal branch of smaller loop is greater than the diagonal branch of larger loop. there is still scope in finding the configuration of grounding grid using transient electromagnetic method as it will be next feasible step taken in fault diagnosis of grounding grid after orientation detection. author contribution usman zia saleem: conceptualization, methodology, software, validation, investigation. safdar raza: supervision, project administration, investigation. inzamam ul haq: resources, data curation, formal analysis. muhammad bilal ashraf: writing review & editing, writing original draft. data availabilty statement the datasets generated during and analyzed during the current study are available from the corresponding author on reasonable request. conflict of interest authors of this paper declare no conflict of interest. funding this paper is composed from research that was not funded by any organization or institution. references ieee guide for safety in ac substation grounding," ieee std 80-2000, pp. 1-192, 2000, doi: 10.1109/ieeestd.2000.91902. ieee std 80-2013 (revision of ieee std 802000/ incorporates ieee std 80-2013/cor 12015) redline. ieee, 2015. b. zhang, j. wu, j. he, and r. zeng, "analysis of transient performance of grounding system considering soil ionization by time domain method," ieee transactions on magnetics, vol. 49, no. 5, pp. 1837-1840, 2013. n. eghtedarpour, m. karimi, and m. tavakoli, "analyzing the effect of substation grounding system on distance relays operation: a documented case," in 2019 international power system conference (psc), 2019: ieee, pp. 275-279. s. huang, z. fu, q. wang, x. zhu, and s. qin, "service life estimation for the small-and medium-sized earth grounding grids," ieee transactions on industry applications, vol. 51, no. 6, pp. 5442-5451, 2015. l. m. popović, "reduction of the fault current passing through the grounding system of an hv substation supplied by cable line," international journal of electrical power & energy systems, vol. 99, pp. 493-499, 2018. e.-s. m. el-refaie, s. e. elmasry, m. abd elrahman, and m. h. abdo, "achievement of the best design for unequally spaced u. z. saleem (et al.) orientation detection of unequally spaced complexed grounding grids using transient electromagnetic method (pp. 18 32) sukkur iba journal of emerging technologies sjet | vol. 4 no. 2 july – december 2021 31 grounding grids," ain shams engineering journal, vol. 6, no. 1, pp. 171-179, 2015. m. mitolo, p. e. sutherland, and r. natarajan, "effects of high fault currents on ground grid design," ieee transactions on industry applications, vol. 46, no. 3, pp. 1118-1124, 2010. m. lorentzou, n. hatziargyriou, and b. papadias, "time domain analysis of grounding electrodes impulse response," ieee transactions on power delivery, vol. 18, no. 2, pp. 517-524, 2003. y. liu, n. theethayi, and r. thottappillil, "an engineering model for transient analysis of grounding system under lightning strikes: nonuniform transmission-line approach," ieee transactions on power delivery, vol. 20, no. 2, pp. 722-730, 2005. r. lucić, i. jurić‐grgić, and z. balaž, "grounding grid transient analysis using the improved transmission line model based on the finite element method," international transactions on electrical energy systems, vol. 23, no. 2, pp. 282-289, 2013. f. xu, c. liu, w. hong, and k. wu, "fast and accurate transient analysis of buried wires and its applications," ieee transactions on electromagnetic compatibility, vol. 56, no. 1, pp. 188-199, 2013. a. jardines, j. guardado, j. torres, j. chavez, and m. hernandez, "a multiconductor transmission line model for grounding grids," international journal of electrical power & energy systems, vol. 60, pp. 24-33, 2014. m. ramamoorty, m. b. narayanan, s. parameswaran, and d. mukhedkar, "transient performance of grounding grids," ieee transactions on power delivery, vol. 4, no. 4, pp. 2053-2059, 1989. b. zhang et al., "numerical analysis of transient performance of grounding systems considering soil ionization by coupling moment method with circuit theory," ieee transactions on magnetics, vol. 41, no. 5, pp. 1440-1443, 2005. l. d. grcev and m. heimbach, "frequency dependent and transient characteristics of substation grounding systems," ieee transactions on power delivery, vol. 12, no. 1, pp. 172-178, 1997. v. dorić, d. poljak, and v. roje, "transient analysis of the grounding electrode based on the wire antenna theory," engineering analysis with boundary elements, vol. 28, no. 7, pp. 801-807, 2004. d. poljak and v. doric, "wire antenna model for transient analysis of simple grounding systems, part i: the vertical grounding electrode," progress in electromagnetics research, vol. 64, pp. 149-166, 2006. d. poljak and v. doric, "wire antenna model for transient analysis of simple grounding systems, part ii: the horizontal grounding electrode," progress in electromagnetics research, vol. 64, pp. 167-189, 2006. d. cavka, b. harrat, d. poljak, b. nekhoul, k. kerroum, and k. e. k. drissi, "wire antenna versus modified transmission line approach to the transient analysis of grounding grid," engineering analysis with boundary elements, vol. 35, no. 10, pp. 1101-1108, 2011. s. šesnić and d. poljak, "antenna model of the horizontal grounding electrode for transient impedance calculation: analytical versus boundary element method," engineering analysis with boundary elements, vol. 37, no. 6, pp. 909-913, 2013. b. nekhoul et al., "an efficient transient analysis of realistic grounding systems: transmission line versus antenna theory approach," engineering analysis with boundary elements, vol. 48, pp. 14-23, 2014. a. qamar, i. ul haq, m. alhaisoni, and n. n. qadri, "detecting grounding grid orientation: transient electromagnetic approach," applied sciences, vol. 9, no. 24, p. 5270, 2019. y. liu, l. xiao, and j. tian, "optimized corrosion diagnosis of large-scale grounding grid," in ieee pes general meeting, 2010: ieee, pp. 1-6. x. zhu, l. cao, j. yao, l. yang, and d. zhao, "research on ground grid diagnosis with topological decomposition and node voltage method," in 2012 spring congress on engineering and technology, 2012: ieee, pp. 1-4. l. j. li, m. f. peng, and k. x. zhao, "fault diagnosis for grounding grids based on genetic algorithm and support vector machine," in advanced materials research, 2013, vol. 787: trans tech publ, pp. 909-913. d. wang and b. he, "practicality analysis for fault diagnosis of medium-scale grounding grid," in 2016 ieee international conference on high voltage engineering and application (ichve), 2016: ieee, pp. 1-4. f. yang et al., "a cycle voltage measurement method and application in grounding grids fault location," energies, vol. 10, no. 11, p. 1929, 2017. x.-l. zhang, x.-h. zhao, y.-g. wang, and n. mo, "development of an electrochemical in situ detection sensor for grounding grid corrosion," corrosion, vol. 66, no. 7, pp. 076001-076001-7, 2010. u. z. saleem (et al.) orientation detection of unequally spaced complexed grounding grids using transient electromagnetic method (pp. 18 32) sukkur iba journal of emerging technologies sjet | vol. 4 no. 2 july – december 2021 32 y. liu, x. cui, and z. zhao, "a magnetic detecting and evaluation method of substation’s grounding grids with break and corrosion," frontiers of electrical and electronic engineering in china, vol. 5, no. 4, pp. 501-504, 2010. c. yu, z. fu, x. hou, h.-m. tai, and x. su, "break-point diagnosis of grounding grids using transient electromagnetic apparent resistivity imaging," ieee transactions on power delivery, vol. 30, no. 6, pp. 2485-2491, 2015. c. yu, z. fu, q. wang, h.-m. tai, and s. qin, "a novel method for fault diagnosis of grounding grids," ieee transactions on industry applications, vol. 51, no. 6, pp. 51825188, 2015. l. xiang and x. cui, "detecting method of conductors and mesh structure of substation’s grounding grids," trans. china electrotech. soc., vol. 28, no. 5, pp. 167-173, 2013. l. chunli, h. wei, y. degui, y. fan, k. xiaokuo, and w. xiaoyu, "topological measurement and characterization of substation grounding grids based on derivative method," international journal of electrical power & energy systems, vol. 63, pp. 158164, 2014. a. qamar, f. yang, w. he, a. jadoon, m. z. khan, and n. xu, "topology measurement of substation's grounding grid by using electromagnetic and derivative method," progress in electromagnetics research, vol. 67, pp. 71-90, 2016. c. yu, z. fu, g. wu, l. zhou, x. zhu, and m. bao, "configuration detection of substation grounding grid using transient electromagnetic method," ieee transactions on industrial electronics, vol. 64, no. 8, pp. 6475-6483, 2017. a. qamar, f. yang, n. xu, and s. a. shah, "solution to the inverse problem regarding the location of substation’s grounding grid by using the derivative method," international journal of applied electromagnetics and mechanics, vol. 56, no. 4, pp. 549-558, 2018. a. k. mohamed, m. a. meju, and s. l. fontes, "deep structure of the northeastern margin of the parnaiba basin, brazil, from magnetotelluric imaging," geophysical prospecting, vol. 50, no. 6, pp. 589-602, 2002. g. xue, y. yan, x. li, and q. di, "transient electromagnetic s‐inversion in tunnel prediction," geophysical research letters, vol. 34, no. 18, 2007. m. metwaly, g. el-qady, u. massoud, a. elkenawy, j. matsushima, and n. al-arifi, "integrated geoelectrical survey for groundwater and shallow subsurface evaluation: case study at siliyin spring, elfayoum, egypt," international journal of earth sciences, vol. 99, no. 6, pp. 1427-1436, 2010. h. tang, h. yang, g. lu, s. chen, j. yue, and z. zhu, "small multi-turn coils based on transient electromagnetic method for coal mine detection," journal of applied geophysics, vol. 169, pp. 165-173, 2019. p. wang, m. li, w. yao, c. su, y. wang, and q. wang, "detection of abandoned waterfilled mine tunnels using the downhole transient electromagnetic method," exploration geophysics, pp. 1-16, 2020. g. xue, w. chen, s. yan, n. zhou, and d. qingyun, "device and method for ground source transient electromagnetic near-field detection and related device," ed: google patents, 2020. z. ye, c. zhang, y. ye, and w. zhu, "application of transient electromagnetic radar in quality evaluation of tunnel composite lining," construction and building materials, vol. 240, p. 117958, 2020. an energy efficient crypto suit for secure underwater sensor communication using genetic algorithm vol. 5, no. 1 | january – june 2022 sjet | p-issn: 2616-7069 |e-issn: 2617-3115 | vol. 5 no. 1 january – june 2022 64 contrast normalization filtering modules for segmentations of retinal blood vessels from color retinal fundus images qamar un nisa1, toufique ahmed soomro2, mehboob khuwaja1, ahmed j. afif3, bs chowdhry1 abstract: vision loss is one of the main complications of eye disease, especially diabetic retinopathy (dr), because dr is a silent disease affecting the retina of the eye and resulting in loss of vision. manual observation of eye disease takes time and delays effective treatment, so computerized methods are used to diagnose eye disease by extracting their features such as blood vessels, optic disc, and other abnormalities. many computerized methods are proposed but they are still lacking to obtain small vessels. to overcome this problem, we have proposed digital image enhancement methods based on image processing techniques for detection of retinal vessels. the proposed method is based on the elimination of uneven illumination using morphological tactics and principal component analysis (pca). the main propose to use the pca to convert the red-greenblue (rgb) channels into signal well contrast image. since the pca technique is used in the preprocessing module to get well contrast image. these initial steps are known as the preprocessing module, and our post-processing module contains the vessel coherence and the double threshold binarization method to obtain an image of the segmented vessels. our proposed method obtained comparable results against existing methods with sensitivity: 0.78, specificity: 0.95 and precision: 0.951 on two databases namely digital retinal images for vessel extraction (drive) and structured analysis of the retina (stare). such performance shows that our proposed method has capability to segment the retinal blood more accurately. as well as it can be tool for ophthalmologist to diagnosis the eye disease. keywords: diabetic retinopathy: retinal image: optic disc: morphological tactics: principle component analysis: double thershold.. 1. introduction the retina is the essential part of the human eye, composed of the light-sensitive layer in the back of the eye. the purpose of the retina is to transmit light into neural signals and accommodate the brain to get explicit 1electronic engineering department, mehran university of engineering and technology, jamshoro, pakistan 2electronic engineering department, quaid-e-awam university of engineering, science and technology, larkana campus. 3department of exploration helmholtz institute freiberg for resource technology (hif), germany. corresponding author: qamarel10@gmail.com knowledge. however, every part of the eye is essential for clear vision. the retina is placed beside the optic nerve, and a small darker round part is placed at the retina’s central region, known as the macula. a major part of mailto:qamarel10@gmail.com contrast normalization filtering modules for segmentations of retinal blood vessels from color retinal fundus images (pp. 64 77) sukkur iba journal of emerging technologies sjet | vol. 5 no. 1 january – june 2022 65 the macula is called the fovea that gives clear vision.[1] retinal eye disease is one primary disease in the list of world health organization. dr has been happened suddenly, and many abnormalities in the retina occurred due to hypertension, unhealthy diet. these factors cause many eye diseases such as retinal detachment, hypertensive retinopathy, neovascular glaucoma, retinitis pigments, and diabetic retinopathy. these kinds of diseases may cause complications, even vision loss impairment if they remain untreated. people having diabetic between ages 20 to 74 years can get diabetic retinopathy (dr). it is estimated that people with diabetes have increased by 20 to 25 million worldwide [2]. diabetic retinopathy is an eye-related disease that affects the geometry of eye blood vessels that may distort or blur vision and cause blindness [3]. the retinal tissue in the human eye is similar to all other parts of human body tissues. the blood received by retinal tissue via small (micro) blood vessels also depends on a continuous blood flow to maintain blood sugar levels. microaneurysms (mas) are caused by an abnormal sugar level in the retinal blood vessels. the dr contains various retinal abnormalities such as cotton wool spots, microaneurysms, exudates, and hemorrhages. these abnormalities cause irreversible blindness due to retinal blood vessel damage. the fundus camera gives the color retinal images. fundus photography captures the interior of eye images via pupil to the back of the eye is called the fundus. fundus camera consists of low power of microscope with an onboard flash camera. optometrists uses low power fundus photography to help get deeper knowledge of ocular health. the fundus is composed of blood vessels, optic disc, retina, macula, and fovea; these are the main retina features of the eye's interior that gives a visualization of the retinal image. an ophthalmologist analyses the obtained retinal image by manually separating the vessels from their backgrounds. a significant number of observer interventions are required in manual segmentation, and it is a time-consuming process [4]. in the last few years, many researchers have been developing advanced techniques for the early detection of disease that can decrease the vision loss risk based on image processing techniques, especially image enhancement and segmentation. many researchers have studied on computerized techniques for analyzing retinal blood vessel segmentation are implemented, but these studies have different issues, especially enhancement of tiny retinal blood vessels [5]. multi-scale line detectors and morphological filters are methods based on the blood vessels segmentation. these methods are failed to address critical challenges in the analysis of retinal imaging, such as the tiny vessels detection before designing the vessel predetections and the removal of a noisy area of the vessels network [2]. however, a computerized system is reliable and able to create a segmented image that is highly desired to replace the previous systems of manual segmentation of blood vessel. the automatic vessel optimization techniques require accurate segmentation of retinal blood vessels. different algorithms are proposed for precise retinal vessel segmentation based on image processing by using filtering method. many filters are used to remove noise pixels, but still, vessels need proper enhancement. due to the noise issue, tiny vessels are not detected, leading to the low sensitivity of methods. we proposed preprocessing module based on adaptive wiener filtering and other basic image processing techniques. we also implemented a postprocessing model based on histogram thresholding to segmented retinal blood vessels. the paper is organized into six sections where: section 1 is based on introduction on dr. section 2 contain the related work, in the section 3 explain the research methodology and elaborated each step of purposed model in detail, section 4 based on database and measures three parameters, section 5 contain on the result analysis and in the last section 6 based on research conclusion and future work. contrast normalization filtering modules for segmentations of retinal blood vessels from color retinal fundus images (pp. 64 77) sukkur iba journal of emerging technologies sjet | vol. 5 no. 1 january – june 2022 66 2. related work many researchers have been working on different blood vessel segmentation methods in the fundus of retinal images [6]. the blood vessels in the retinal images are multidirectionally distribute and make it is difficult to isolate accurately. the vascular network of retinal image containing veins as well as arteries. since the blood vessels have root and branches that mimic tree. the blood vessels have a tabular shape with gradually varying orientations and widths. the low and varied contrast in the vessels makes it difficult to see the vessels accurately. accurate segmentation of retinal blood vessels obtained by using different methods such as vessel tracking, morphological processing, filtering, machine learning, image processing techniques, and deep learning. recently, toufique et al. [7] developed several filter-based methods to increase the visibility of retinal blood vessels to get accurate segmentation of retinal blood vessels. lathen et al. [8] implemented an enhanced local phase-based filter for optimal vessel improvement, and it extracts retinal blood vessels in the same vein using an intensity-based filter. there are two automated retinal vessel segmentation methods: supervised and unsupervised retinal vessel segmentation [9]. the supervised retinal vessel segmentation method requires both user interruption and labeled data to train the vessels and non-vessel pixel classifier [10]. the classifiers are widely used in supervised retinal vessel segmentation methods, and these classifiers are artificial neural networks (ann) [11] svm (support vector machine) [12,13], gmm (gaussian mixture models) [14,15], and k-nearest neighbors [10]. the unsupervised retinal vessel segmentation methods do not require any user interruption. the unsupervised retinal vessel segmentation methods use mathematical modeling tactics or imaging techniques to classify vessels and non-vessel pixels in an image, and they don't require any training data [9,16, 17]. the performance of supervised methods is significantly giving better result than unsupervised retinal vessel segmentation method. however, the segmentation of supervised method initially obtaining the required data, such as expert training sampling datasets, and might be problematic with time. the most significant supervised technique disadvantage during vessel segmentation is the arduous vessels classification and the pixel value of the background. yin et al. [18] developed a method based on the segmentation of retinal blood vessel patterns. the proposed designs define which pixels are vessels and which are non-vessels. however, this approach gives false detection on pathology images. although a learning method has been introduced to improve their method [19,20] it has yet to be validated with retinal vessels mapping, and the tiny vessels have not been detected. our proposed method is the un-supervised retinal segmentation method. the pre-processing steps of our methods use in the supervised segmentation methods to improve the segmentation of retinal vessels. among the unsupervised methods, mendonca et al. [21] introduced a method for segmentation of retinal blood vessels, and their approach is based on morphological reconstruction tactics. an offset difference of gaussian filter threshold (doog) and their methods did not pick the small vessel, although it gave several erroneous pixel detections. the techniques of the multiscale retinal vessel [22] improved in [23] by exploiting the study of the intensities of retinal images, which is related to the pixels of the vessels responding to specific pixels during the process of image acquisition. after that, multiscale data is combined using a diameterdependent equalization factor. however, their method provided pixel detection of false vessels on some retinal images, particularly those with a center light reflex. toufique ahmed et al [24 proposed an unsupervised image processing method for detecting the small vessel based on the log filter. this method performs better, but some tiny vessels do not detectable. shankar, k., et al. [25] developed an automated hyperparameter tuning inception-v4 (hptiv4) model to classify and detect dr from color retinal images. contrast normalization filtering modules for segmentations of retinal blood vessels from color retinal fundus images (pp. 64 77) sukkur iba journal of emerging technologies sjet | vol. 5 no. 1 january – june 2022 67 fig. 1. proposed model this model consists of various sub-processes such as initial step pre-processing, feature extraction, segmentation, and classification. yin, pengshuai et al. [26], implement a novel method, segment the biomedical images by deep guided network based on guided image filter for vessel segmentation, cup segmentation, and an optic disc of the retinal image. toufique a., et al. [27] evaluated contrast normalization step for segmentation of retinal vessel. 3. proposed method segmentation of accurate blood vessels are a challenging task for the different applications of medical images specifically vessel image segmentation from color retinal fundus images. the segmented blood vessel retinal images contain several issues that make it difficult to diagnose the process of vessel segmentation due to uneven illumination, varying low contrast, and noise. many researchers have been developing advanced techniques for the early detection of disease that can decrease vision loss and improve the detection of tiny vessels performance. our proposed methodology is to improve the detection of tiny vessels and retaining an acceptable level of accuracy. this method is based on main two steps: pre-processing and post-processing to obtain an image of the wellsegmented vessels. the proposed model is shown in the figure.1 while all steps are elaborated as follows. many systems for retinal image segmentation and analysis use preprocessing as the first step. the preprocessing step in our proposed model is based on two main steps to obtain the wellsegmented image, while the process is shown in figure 1. 3.1 processing of color retinal fundus image our designed retinal segmentation algorithm used retinal color fundus images as input images to give an enhanced image in prepre-processing module color retinal fundus image uneven illumination removal color-to-grey image (pca) final greyscale image post-processing module coherence of retinal blood vessels binarization of retinal blood vessels retinal blood vessels segmented image contrast normalization filtering modules for segmentations of retinal blood vessels from color retinal fundus images (pp. 64 77) sukkur iba journal of emerging technologies sjet | vol. 5 no. 1 january – june 2022 68 processing step. our pre-processing module used monochrome-types input images while most of the retinal image databases are monochrome in nature and the publicly available databases contain color retinal images are captured by a camera known as fundus cameras. the color retinal images contain three types of channels: red, green, and blue channels (rgb channels). each channel carries its own information and to get the appropriate input image for the further processing as shown in the figure 2. (a) (b) (c) (d) fig. 2. select the most suitable channel from retinal image. where the original retinal color fundus image is shown in (a), and (b) retinal color image in red channel, (c) retinal color image in green channel, (d) retinal color image in blue channel. the red channel contains both luminous information as well as noise [30] and the green channel contain least number of noisy pixel and give better vessels observation, and the blue channel contain shadow and more noise. however, green channel has a good contrast than the red and blue channels, and blood vessels are more visible in the green channel. a grayscale well-segmented output image will be obtained for further processing, and we select a grayscale image in our model for further processing because it requires less computing resources and takes less time of processing compared to a color (rgb) image. the color images have a minimal number of advantages in the application based on image processing. color images do process additional information, which can increase the quantity of processing data required to obtain the intended result in any segmentation method. after the selection of the grayscale image, the removal of uneven illumination is analyzed in the next step to achieve a uniform level in the retinal blood vessel against their pixels in the background. 3.2 removal of uneven illumination some basic image processing techniques are used to solve the issue of uneven illumination to obtain a well uniform contrast image. the main reason for eliminating the uneven illumination is each (rgb) channel appears large variation intensity background that effect on the observation of retinal blood vessel. however, we used morphological operations, adaptive wiener filtering, and lee filtering. we tested in three ways: one based on morphological operation, second based on adaptive wiener filtering, and last on lee filtering. adaptive wiener filtering: adaptive wiener filtering is based on the least mean square method, and it is applied to the noisy image according to statistical measurement. this filter can remove the noise from the image. their main objective is to minimize the mean square error between the filtered image and tuoriginal images. this filter modifies each pixel’s values properties, and it is required to remove the high-frequency region of image and achieve an edge-preserving of an image. a local adaptive filter is dependent on in a defined window region of image m x n are the variance and mean. this filter work based on a computation of local image variance, however, when the local variance of the image is large the little smoothing is done in a lesser amount, and if the local variance of the image is smaller the filter performs more smoothing. an adaptive filter is more selective than a linear filter of comparable type because the adaptive contrast normalization filtering modules for segmentations of retinal blood vessels from color retinal fundus images (pp. 64 77) sukkur iba journal of emerging technologies sjet | vol. 5 no. 1 january – june 2022 69 filter preserves the edges as well as other highfrequency regions of the image. the pixelwise adaptive wiener technique is used in the adaptive wiener filter as shown in figure 3. the statistics variables are taken from a local neighborhood of each pixel are used in this method. the two statistical variables such as variance and means on which wiener filter in a window size of image is based. the adaptive wiener filter has three steps with its operation. in the first step, the mask is created by calculating the mean of the noise-contained image. this calculation uses the m x n local neighborhood of each pixel in the image and the mathematical problem for this step is represented by µ= 1 𝑁𝑀 ∑ ∑ 𝐼(𝑛1, 𝑛2) 𝑁 𝑛2=1 𝑁 𝑛1=1 (1) next step, the mask is created by calculating the variance of the noise-contained image. this calculation uses the m x n local neighborhood of each pixel in the image and the mathematical problem for this step is represented by µ= 1 𝑁𝑀 ∑ ∑ 𝐼2(𝑛1, 𝑛2) − µ 2𝑁 𝑛2=1 𝑁 𝑛1=1 (2) in the last step, the adaptive wiener creates a pixel-wise wiener filter using these estimates. the mathematical problem at this step is expressed by the first step equation (1) f (𝑛1𝑛2) = µ + 𝜎2+𝑣 𝜎2 (𝐼(𝑛1, 𝑛2)) − µ) (3) where, v is noise variance. if their noise variance is not specified, however, the adaptive wiener filter will use the average of all calculated local variances. the adaptive wiener filter output of each channel of retinal color fundus image is shown in figure 3. lee filtering: the lee filter develops the output image via integrating the central pixel intensity in a neighborhood pixel with the mask's average intensity value. this filter is better in edge preservation. this approach uses local statistics to preserve details and is based on a multiplicative speckle model. (a) (b) (c) (d) fig. 3. adaptive wiener filter output of each channel of retinal color fundus image. (a) input image (b) red channel, (c) green channel, (d) blue channel this filter is better in edge preservation. this approach uses local statistics to preserve details and is based on a multiplicative speckle model. the lee filter works on mean and variance values [31]. if the variance area is small the smoothing operation is done but if an area of variance is high, then little smoothing is done. in contrast, this filter can preserve details in both low as well as in high contrast hence lee filter has adaptive in nature. the lee filter mathematical method is expressed in equation (4). 𝑖𝑚𝑔(𝑚, 𝑛) = 𝑖𝑚 + 𝑤 × (𝐶𝑝 − 𝑖𝑚) .. (4) where, img represents the pixel value after filtering, and im means the filter window's mean intensity, c_p defines the center pixel, and w indicates the filter window's width. the filter window calculated by 𝑤 = 𝜎 2(𝜎 2 + 𝜌2) (5) the 𝜌2 represented as additive noise variance, and 𝜎 2 is pixel variance calculated as 𝜎 2 = 1 𝑁 ∑ (𝑋𝑗 ) 2𝑁−1 𝐽=0 (6) 𝜌2 = 1 𝑀 ∑ (𝑌𝑗 ) 2𝑀−1 𝐽=0 (7) contrast normalization filtering modules for segmentations of retinal blood vessels from color retinal fundus images (pp. 64 77) sukkur iba journal of emerging technologies sjet | vol. 5 no. 1 january – june 2022 70 where m is the image size and n is the window size, x_j and y_j are each pixel value in image at j. the lee filter has the drawback of being unable to efficiently eliminate speckle noise near edges. the output of lee filtering is shown in figure 4. (a) (b) (c) (d) fig. 4. lee filter output of each channel of retinal color fundus image. (a) input image (b) red channel, (c) green channel, (d) blue channel. we selected the best method by comparing the contrast level of the output image of each method and processed it for further processing. but these filtering techniques either adaptive wiener filtering and lee filtering do not give proper unform image as shown in figure 3 and 4. we validated the morphological operation which works successfully and achieve well contrast image. morphological image processing operations: morphological image processing approaches are a set of digital image processing techniques which contains mathematical morphology tactics. the main functionality of morphological operations is used for uniform contrast variation. morphological operations are used to eliminate noisy pixels and uneven illumination of each grayscale retinal image. it is clearly observed that each channel has uneven illumination as well as noise as shown in the figure 5. there are differences between background and intensities level of blood vessel, according to the analysis. the changes in these intensity levels produce an uneven illumination and noise problem since the blood vessel intensity levels are much lower than the background intensity level. (a) (b) (c) (d) fig. 5. output of morphological operation. (a) input image (b) red channel, (c) green channel, (d) blue channel. there are many mathematical morphological approaches are used for image processing, the most used are closing and opening operations namely: top hat and bottom hat operation. each rgb channel of retinal color fundus images are processed through both approaches to know how much noise affects the background of a retinal blood vessel. the top hat morphological operation is implemented as varying contrast of retinal blood vessels improved. the bottom hat morphological operation is implemented for improved the background of the image and give a sort of information to the retinal image, and it makes blood vessels more visible or enhanced while decreasing the level of noise effect on blood vessels. finally, noise problem, as well as uneven illumination of background retinal image is eliminated contrast normalization filtering modules for segmentations of retinal blood vessels from color retinal fundus images (pp. 64 77) sukkur iba journal of emerging technologies sjet | vol. 5 no. 1 january – june 2022 71 through subtracting top hat image from bottom hat image, with maintained these both issue: noise and uneven illumination, we obtained more enhanced final vessel image and observed that the vessels are more visible in figure 5. after comparing the output of all these filtering techniques, we can observe that more detailed of image is achieved from morphological operations as well as background contains uniformity also. as, we measured the contrasted of green channel of each vessel against their background of these techniques. the morphological techniques gave 60.12 contrast as compared to 37.28 of adaptive winner filter and 38.1 of lee filter. 3.3 color conversion into grayscale image by pca techniques the grayscale images give more promising results because it used mainly for examining the details of an image. grayscale image is crucial to maintain visual features in medical images to detect the most vital clues. fig. 6. pca based conversion from rgb to grayscale image the observation of retinal blood vessels plays a vital role in observing the progression of eye illnesses in the retinal image. in this stage, the main goal is to merge the three colors (rgb) channels into a single grayscale channel image while converting rgb to grayscale show more promising outcomes. whereas rgb background equalization of the retinal channels provides adequate representation for subsequent processing. in order to create a single grayscale image, used all three channels: red, green, and blue channels instead of the single green channel. the principal component analysis (pca) is used to convert a color rgb image into a grayscale image. the process is shown in figure 6. our method prefers to use all three rgb channels with the use of pca to obtain a single grayscale image by including several processing steps: 1) the color to grayscale conversation method is concerned with the vector color rgb images formulation (𝐼𝑟𝑔𝑏 ∈ 𝑅 3) through-loading three color channels: red, green, and blue simultaneously. further, a zero mean of ycbcr image (𝐼𝑌𝐶𝑏𝐶𝑟 ∈ 𝑅 3)is converted out by its rgb version to unlink such chrominance and luminance channels through transfer function f (.). 2) the eigenvectors (𝑣1 ≥ 𝑣2 ≥ 𝑣3 ∈ 𝑅 3) and their corresponding eigenvalues (λ1 ≥ λ2 ≥ λ3 ∈ 𝑅 1) are determined by the pca method. the final (𝐼𝑔𝑟𝑎𝑦 ∈ 𝑅 3) grayscale image is determined via three projections of the weighted direct blend, where weights are determined by their eigenvalue’s percentage. as seen in figure , the final output is scaled to the [0, 1] range. within three subframe projections, we achieved the final resulting grayscale image. in the first subframe, projection leads the color-to-gray transfer results because of its contrast normalization filtering modules for segmentations of retinal blood vessels from color retinal fundus images (pp. 64 77) sukkur iba journal of emerging technologies sjet | vol. 5 no. 1 january – june 2022 72 significantly larger eigenvalue while other two subframe projections assist in a limited way to filling a colored image detail in the final grayscale image as shown in figure 6. the principal component analysis (pca) conversion is utilized to the axes rotate from color space intensity values to orthogonal axes to get an effective color conversion. in the first subframe, projection leads the color-to-gray transfer results because of its significantly larger eigenvalue while other two subframe projections assist in a limited way to filling a colored image detail in the final grayscale image as shown in figure 6. the principal component analysis (pca) conversion is utilized to the axes rotate from color space intensity values to orthogonal axes to get an effective color conversion. 4. post processing module the post-processing step is used to remove tiny objects from the binary image in order to binary image get well-connected vessels. this step contains the segmentation of the vessels in the retinal images. the main objective of post-processing is to analyze the effect of our pre-processing model and to assess its performance in the vessel segmentation. the post-processing step in our proposed model is based on two steps: 1. coherence of retinal blood vessels network using contrast normalization filters. 2. binarization method to achieve well segmented vessels image. the homogenization of the background improves the overall contrast of the retinal image, it is observed that discontinuities in the vessels are present. to resolve this problem, we used a second order gaussian derivative filter to normalize the pixels intensities between the connected vessels and give an initial coherent vessels image. but still, the small vessels do not maintain the same consistency with their background. it is therefore challenging to binarize the vessels, for getting well vessels image, we used anisotropic diffusion filtering proposed by [32], anisotropic diffusion filtering is used to increase the coherence of tiny vessels. the output of both coherence filters is shown in figure 7. it clearly observed that tiny vessels are more detected in final coherence image fig 7(b), and it leads to give more accurate segmented image in binarization process. fig(a) fig(b) fig. 7. coherence of vessels. fig (a) represents the initial coherent image, and fig (b) represents the final coherent image. 4.1 binary output: final segmented image the output images of final coherent vessels still having noisy pixels, as well as some intensity variations, remain and it makes it difficult to detect tiny vessels and connect them. a better vessel segmented output image is achieved here by using the double threshold method. this method is based on morphological reconstruction images. this reconstruction morphological image is used for the final binary output image obtained and their structure is comprised of two binary images namely: 1. mask image 2. marker image. we assume that a and b are two binary images: a is mask image and b is marker images of same type of domain d such as a ∁ b i.e:∀𝑝 ∈ 𝐷, 𝐵(𝑝) = 1 ⇒ 𝐴(𝑝) = 1 are used in reconstruction morphological image to provide binary image detail. both marker and mask images are achieved by image histogram as shown in the figure 8. the figure 8(a) shown the mask image, which is achieved by applying a mean image value based on the image histogram, and the marker image is achieved by multiplying with contrast normalization filtering modules for segmentations of retinal blood vessels from color retinal fundus images (pp. 64 77) sukkur iba journal of emerging technologies sjet | vol. 5 no. 1 january – june 2022 73 standard derivation value 0.9 and subtract it by a mean image value image based on the histogram as shown in figure (b). the final binary output image as shown in figure 8(c) and final binary image is achieved by applying morphological reconstruction operation. the mask image has more noise than the marker image and background noise is removed by multiply a standard derivation. the false pixels in the marker image background reduces, as a result, a small vessel is detected and get a better marker image by chosen 0.9 standard derivations. we use image processing techniques to eliminate tiny objects against the binary image and obtain an accurate retinal vessel image. because some isolated noise segments pixels are detected as false vessels because of the morphologically reconstructed process. the small objects are removed from the reconstructed image so that the image only contains a well-connected vessel. thus, small areas of fewer than 50 pixels are removed for this task to obtain the final binary image as shown in figure 8(d). 4.2 proposed algorithm our proposed method comprises of two main steps: 1. pre-processing 2. post processing. the preprocessing step is based on following three stages. 1. firstly, the retinal color fundus image proceeds as input and then convert the retinal image into rgb channels and subsequently each channel covert into greyscale images. 2. this stage is related to the removal of uneven illumination. to manage the uneven illumination from three channel by evaluated the morphological operation, lee filtering, and adaptive wiener filtering. when compared to the morphological operation, lee filter, and adaptive wiener filtering output result. the morphological operation produced well contrast image. 3. this stage is based on machine learning techniques for obtained the well contrasted grayscale image. we convert rgb image into grayscale image by using pca techniques. the postprocessing steps are based on following stages. 4. the first stage of post processing related to examining the normalization of small vessel and it is crucial component in boosting the vessels sensitivity. contrast coherent filters are used to obtain the coherent vessels image. 5. stage 3. the third stage is based on double threshold binarization to get well segmented image. (a) (b) (c) (d) fig. 8. 5. database and computing parameters we used two publicly available database for validating our proposed method. in this section, we introduce our database and measuring parameters also. 5.1 database we used the digital retinal images for vessel extraction (drive) and structured analysis of the retina (stare) database. these databases totally contained the 40 images, and each image have ground truth contrast normalization filtering modules for segmentations of retinal blood vessels from color retinal fundus images (pp. 64 77) sukkur iba journal of emerging technologies sjet | vol. 5 no. 1 january – june 2022 74 image. almost all researchers used these databases to validate their algorithm. it gives opportunity to compare the performance of our methods against existing methods. 5.2 measuring parameters the most used parameters are computed, and these parameters are sensitivity, specificity, and accuracy. these three parameters are used to validate the retinal segmentation algorithm. the sensitivity and specificity is used to measure the ability of the vessels and nonvessels pixels classifications. accuracy measured the overall performance of the algorithm. the mathematically representation of these parameters are shown below. sensitivity (se) = tp tp+fn (8) specificity (sp) = tn tn+fp (9) accuracy (ac) = tp+tn tp+fp+tn+fn (10) where, tp, tn,fp and fn are true positive pixels intensity, true negative pixels intensity, false positive pixels intensity and false negative intensity. 6. experimental results analysis our experimental result analysis section contains analysis of performance of our method on databases and comparison analysis with existing methods. 6.1 performance on database the performance of our algorithm is shown in table 1. it can be observed that our method gave accuracy of 0.948 on drive and 0.941 on stare with sensitivity of 0.80 on drive and 0.79 on stare. we analyzed the images also as shown in figure 9. it is clearly analyzed that proposed method gives well segmented images and even tiny vessels are clearly observable and our method output is comparable with corresponding ground-truth. table i. performance of our proposed method on databases database se sp ac drive 0.80 0.961 0.948 stare 0.79 0.956 0.941 input image ground truth image output image fig. 9. final output of proposed algorithm based on drive and stare database. 6.2 comparison with existing methods the method’s validation for accurate blood vessels segmentation is proven by comparing with performance of previous methods. many researchers use the two most extensively used publicly available databases, drive and stare, to evaluate their approaches. the table 2 shows the comparison of performance of our proposed method with existing methods. our proposed method is based on tactics of image processing and has given higher sensitivity and accuracy (se=0.80, acc=0.948 and se=0.79, acc=0.941) on both drive and stare database than other pervious method except toufique et al [44] as well as toufique et al [45] method which have higher accuracy and sensitivity near to 96% and 81% respectively than our proposed method. it can be clearly observed that our method gave comparable performance as compared to existing methods, and it shows that our proposed method has capability to segment the retinal blood more accurately. this proposed method can be provided easy framework for ophthalmologist to more contrast normalization filtering modules for segmentations of retinal blood vessels from color retinal fundus images (pp. 64 77) sukkur iba journal of emerging technologies sjet | vol. 5 no. 1 january – june 2022 75 accurately screen for retinal disorders and recommended for early treatment. table ii. comparison of proposed method against existing methods method year drive stare se sp ac se sp ac zhao et al [33] 2016 0.716 0.978 0.944 0.776 0.954 0.943 melinscak et al [34] 2016 0.946 toufique et al [35] 2016 0.714 0.968 0.946 0.709 0.965 0.942 khan et al [36] 2016 0.737 0.967 0.951 0.736 0.971 0.951 toufique et al [37] 2017 0.752 0.976 0.943 0.784 0.981 0.961 toufique et al [38] 2017 0.746 0.966 0.952 0.755 0,959 0.951 toufique et al [39] 2017 0.746 0.917 0.948 0.748 0,922 0.947 toufique et al [40] 2018 0.752 0.976 0.953 0.786 0.982 0.967 toufique et al [41] 2018 0.739 0.956 0.950 0.784 0.962 0.947 khan et al [42] 2018 0.769 0.965 0.950 0.752 0.981 0.951 toufique et al [43] 2019 0.745 0.962 0.948 0.784 0.976 0.951 toufique et al [44] 2019 0.802 0.974 0.959 0.801 0.969 0,961 toufique et al [45] 2021 0.812 0.971 0.963 0.809 0.969 0.958 purposed method 2021 0.80 0.961 0.948 0.79 0.956 0.941 7. conclusion changes in the structure of the retinal blood vessel in fundus image that can be used as a diagnostic parameter for eye diseases, especially dr. for the diagnosis of eye diseases, precise segmentation of the retinal vessels is required. many methods have been proposed on the segmentation of retinal blood vessel but there is still need for improvement in the accurate detection of small vessels. in this research paper, we have implemented and validated the digital image contrast enhancement method based on image processing tactics and gives segmented vessels images accurately in which especially more tiny vessels are detected. the goal was to solve the issues of varying low contrast and other challenges in analysis of color fundus images, that make it challenging to accurate segmentation of blood vessels. the segmentation is carried out in the postprocessing, but the post-processing module depends on the pre-processing module. we proposed the well preprocessing module to get a well contrasted image, and it impacted the postprocessing modulus and gave a well segmented retinal vessel image. our proposed method is validated on public databases, namely drive and stare. the method achieved performance comparable to existing methods and it achieved higher level of contrast normalization filtering modules for segmentations of retinal blood vessels from color retinal fundus images (pp. 64 77) sukkur iba journal of emerging technologies sjet | vol. 5 no. 1 january – june 2022 76 sensitivity and segmentation accuracy. our proposed method has capability to be used to a diagnostic tool for eye diseases in the future for timely recommended treatment. references [1] li, xiaotao, and xiang li. "the antidepressant effect of light therapy from retinal projections." neuroscience bulletin 34.2 (2018): 359-368. [2] soomro, toufique a., et al. "role of image contrast enhancement technique for ophthalmologist as diagnostic tool for diabetic retinopathy." 2016 international conference on digital image computing: techniques and applications (dicta). ieee, 2016 [3] s. chaudhuri, s. chatterjee, n. katz, m. nelson, and m. goldbaum, ‘‘detection of blood vessels in retinal images using two-dimensional matched filters,’’ ieee trans. med. imag., vol. 8, no. 3, pp. 263–269, sep. 1989. [4] pakter, helena m., et al. "measuring arteriolar-tovenous ratio in retinal photography of patients with hypertension: development and application of a new semi automated method." american journal of hypertension 18.3 (2005): 417-421. [5] toufique ahmed soomro, junbin gao, tariq m khan, ahmad fadzil m hani, mohammad a. u. khan, and manoranjan paul, “computerised approaches for the detection of diabetic retinopathy using retinal fundus images: a survey,” journal of pattern analysis and application, pp. 1–35, 2017. [6] soomro, toufique ahmed, et al. "deep learning models for retinal blood vessels segmentation: a review." ieee access 7 (2019): 71696-71717. [7] soomro, toufique ahmed, et al. "impact of image enhancement technique on cnn model for retinal blood vessels segmentation." ieee access 7 (2019): 158183-158197 [8] lathen, g.; jonasson, j.; borga, m. blood vessel segmentation using multi-scale quadrature filtering. pattern recognit. lett. 2010, 31, 762–67. [9] sun, k.; chen, z.; jiang, s. local morphology fitting active contour for automatic vascular segmentation. ieee trans. -bio-med eng. 2012, 59, 464–473 [10] staal, j.; abràmoff, m.d.; niemeijer, m.; viergever, m.a.; van ginneken, b. ridge-based vessel segmentation in color images of the retina. ieee trans. med. imaging 2004, 23, 501–509. [11] sinthanayothin, c.; boyce, j.f.; cook, h.l.; williamson, t.h. automated localization of the optic disc, fovea, and retinal blood vessels from digital color fundus images. br. j. ophthalmol. 1999, 83, 890–902. [12] xing, y.; qinmu, p.; yuan, y.; yiu-ming, c.; jiajia, l. segmentation of retinal blood vessels using the radial projection and semi-supervised approach. pattern recognit. 2011, 44, 10–11. [13] ricci, e.; perfetti, r. retinal blood vessel segmentation using line operators and support vector classification. ieee trans. med. imaging 2007, 26, 1357–1365. [14] marin, d.; aquino, a.; gegundez-arias, m.e.; bravo, j.m. a new supervised method for blood vessel segmentation in retinal images by using gray-level and moment invariants-based features. ieee trans. med. imaging 2011, 30, 146– 158. [15] soares, joão vb, et al. "retinal vessel segmentation using the 2-d gabor wavelet and supervised classification." ieee transactions on medical imaging 25.9 (2006): 1214-1222. [16] bankhead, peter, et al. "fast retinal vessel detection and measurement using wavelets and edge location refinement." plos one 7.3 (2012): e32435. [17] al-diri, bashir, andrew hunter, and david steel. "an active contour model for segmenting and measuring retinal vessels." ieee transactions on medical imaging 28.9 (2009): 1488-1497 [18] yin, xiaoxia, et al. "accurate image analysis of the retina using hessian matrix and binarisation of thresholded entropy with application of texture mapping." plos one 9.4 (2014): e95943. [19] liskowski, paweł, and krzysztof krawiec. "segmenting retinal blood vessels with deep neural networks." ieee transactions on medical imaging 35.11 (2016): 2369-2380. [20] li, qiaoliang, et al. "a cross-modality learning approach for vessel segmentation in retinal images." ieee transactions on medical imaging 35.1 (2015): 109-118. [21] mendonca, ana maria, and aurelio campilho. "segmentation of retinal blood vessels by combining the detection of centerlines and morphological reconstruction." ieee transactions on medical imaging 25.9 (2006): 1200-1213. [22] martínez-pérez, m. elena, et al. "retinal blood vessel segmentation by means of scale-space analysis and region growing." international conference on medical image computing and computer-assisted intervention. springer, berlin, heidelberg, 1999. [23] martinez-perez, m. elena, et al. "segmentation of blood vessels from red-free and fluorescein retinal images." medical image analysis 11.1 (2007): 4761. [24] shankar, k., et al. "hyperparameter tuning deep learning for diabetic retinopathy fundus image classification." ieee access 8 (2020): 118164118173. [25] yin, pengshuai, et al. "deep guidance network for biomedical image segmentation." ieee access 8 (2020): 116106-116116. [26] soomro, toufique ahmed, et al. "contrast normalization steps for increased sensitivity of a retinal image segmentation method." signal, image and video processing 11.8 (2017): 1509-1517. contrast normalization filtering modules for segmentations of retinal blood vessels from color retinal fundus images (pp. 64 77) sukkur iba journal of emerging technologies sjet | vol. 5 no. 1 january – june 2022 77 [27] azzopardi, george, et al. "trainable cosfire filters for vessel delineation with application to retinal images." medical image analysis 19.1 (2015): 46-57. [28] elseid, arwa ahmed gasm, mohamed eltahir elmanna, and alnazier osman hamza. "evaluation of spatial filtering techniques in retinal fundus images." american journal of artificial intelligence 2.2 (2018): 16. [29] soomro, toufique ahmed, et al. "retinal blood vessels extraction of challenging images." australasian conference on data mining. springer, singapore, 2018. [30] j. lee, “digital image enhancement and noise filtering by use of local statistics,” ieee trans. pattern anal. mach. intel., vol. pami-2, no. 2, pp. 165–168, 1980 march. [31] gottschlich, carsten, and c-b. schönlieb. "oriented diffusion filtering for enhancing lowquality fingerprint images." iet biometrics 1.2 (2012): 105-113. [32] y. zhao, l. rada, k. chen, s. p. harding, and y. zheng, ‘‘automated vessel segmentation using infinite perimeter active contour model with hybrid region information with application to retinal images,’’ ieee trans. med. imag., vol. 34, no. 9, pp. 1797–1807, sep. 2015. [33] m. melinščak, p. prentašić, and s. lončarić, ‘‘retinal vessel segmentation using deep neural networks,’’ in proc. int. conf. comput. vis. theory appl., 2015, pp. 1–6 [34] t. a. soomro, m. a. u. khan, j. gao, t. m. khan, m. paul, and n. mir, ‘‘automatic retinal vessel extraction algorithm,’’ in proc. int. conf. digit. image comput., techn. appl. (dicta), nov. 2016, pp. 1–8 [35] m. a. u. khan, t. a. soomro, t. m. khan, d. g. bailey, j. gao, and n. mir, ‘‘automatic retinal vessel extraction algorithm based on contrastsensitive schemes,’’ in proc. int. conf. image vis. comput. new zealand (ivcnz), nov. 2016, pp. 1– 5 [36] t. a. soomro, t. m. khan, m. a. u. khan, j. gao, m. paul, and l. zheng, ‘‘impact of ica-based image enhancement technique on retinal blood vessels segmentation,’’ ieee access, vol. 6, pp. 3524–3538, 2018. [37] t. a. soomro, j. gao, z. lihong, a. j. afifi, s. soomro, and m. paul, ‘‘retinal blood vessels extraction of challenging images,’’ in data mining (communications in computer and information science), vol. 996. singapore: springer, 2019, pp. 347–359. [38] t. a. soomro, a. j. afifi, j. gao, o. hellwich, m. a. u. khan, m. paul, and l. zheng, ‘‘boosting sensitivity of a retinal vessel segmentation algorithm with convolutional neural network,’’ in proc. int. conf. digit. image comput., techn. appl. (dicta), nov. 2017. [39] t. a. soomro, t. m. khan, m. a. u. khan, j. gao, m. paul, and l. zheng, ‘‘impact of ica-based image enhancement technique on retinal blood vessels segmentation,’’ ieee access, vol. 6, pp. 3524–3538, 2018. [40] t. a. soomro, a. j. afifi, j. gao, o. hellwich, m. paul, and l. zheng, ‘‘strided u-net model: retinal vessels segmentation using dice loss,’’ in proc. digit. image comput., techn. appl. (dicta), dec. 2018, pp. 1–8. [41] m. k. t. m. khan and d. t. a. bailey soomro, ‘‘a generalized multi-scale line-detection method to boost retinal vessel segmentation sensitivity,’’ pattern anal. appl., vol. 22, no. 3, pp. 1177–1196, 2018. [42] t. a. soomro, j. gao, z. lihong, a. j. afifi, s. soomro, and m. paul, ‘‘retinal blood vessels extraction of challenging images,’’ in data mining (communications in computer and information science), vol. 996, nos. 1–12. singapore: springer, 2019. [43] t. a. soomro, a. j. afifi, a. ali shah, s. soomro, g. a. baloch, l. zheng, m. yin, and j. gao, ‘‘impact of image enhancement technique on cnn model for retinal blood vessels segmentation,’’ ieee access, vol. 7, pp. 158183–158197, 2019. [44] soomro, t.a.; ali, a.; jandan, n.a.; afifi, a.j.; irfan, m.; alqhtani, s.; glowacz, a.; alqahtani, a.; tadeusiewicz, r.; kantoch, e.; zheng, l. impact of novel image preprocessing techniques on retinal vessel segmentation. electronics 2021, 10, 2297. https://doi.org/10.3390/electronics10182297 vol. 5, no. 2 | july – december 2022 sjet | p-issn: 2616-7069 | e-issn: 2617-3115 | vol. 5 no. 2 july – december 2022 18 wireless sensor networks-based smart agriculture: sensing technologies, application and future directions mushtaque ahmed rahu1, sarang karim2*, rehan shams3*, ayaz ahmed hoshu4, abdul fattah chandio1 abstract: with the advent of the latest sensing technologies and wireless sensor networks (wsn), agricultural tasks can be performed quickly, adequately and precisely. these practices are termed smart agriculture. in this paper, we discuss various sensing technologies that enable smart agriculture. later, a system based on wsn has been designed to monitor agricultural parameters. the proposed system has been deployed in a wheat field. this work aims to increase the quality and productivity of the wheat crops and minimize the extensive field visits of the farmers. this system enables precision agriculture by periodically measuring the three most key parameters (temperature, light, and water level) for achieving a remarkable increase in quality, productivity and growth of the wheat crops. thus, this system helps the agriculturists, landowners and research experts to monitor these parameters at the base station without going to the field site. a gui tool is also designed to display the measured data and stored it in the database accordingly. while designing this system; iris mote, mda100 data acquisition board, and mib520 usb interface board are employed. we use tinyos operating system for the development of codes for wireless nodes and the gui tool is designed in microsoft visual studio. zigbee ieee 802.15.4 protocol and direct topology are used for the communication of nodes with the base station. in last, we also discuss future research directions. keywords: wireless sensor networks, smart agriculture, precision agriculture, sensing technologies, wheat crops. pakistan, being an agricultural country stabilizes its economy through agricultural projects. the economy of most of the population depends on the outputs gained from the agriculture sector. it fulfils the major ingredient of food for mankind and other living organisms on earth. modern technology 1department of electronic engineering, quaid-e-awam university of engineering, science and technology, nawabshah 67450, pakistan. 2department of telecommunication engineering, quaid-e-awam university of engineering, science and technology, nawabshah 67450, pakistan. 3department of telecommunication engineering, sir syed university of engineering and technology, karachi 75300 pakistan. 4department of electronic engineering, quaid-e-awam university of engineering, science and technology, larkana campus, larkana 77150, pakistan. corresponding author: r.shams@ssuet.edu.pk and sarangkarim@quest.edu.pk can bring a remarkable increase in the production and quality rate of crops. through modern techniques and technologies not only the human efforts can be reduced but agricultural expenditures from sowing to harvesting can also be minimized. two basic needs of humans can only be fulfilled from mailto:r.shams@ssuet.edu.pk mailto:sarangkarim@quest.edu.pk wireless sensor networks-based smart agriculture sensing technologies, application and future directions (pp. 18 32) sukkur iba journal of emerging technologies sjet | vol. 5 no. 2 july – december 2022 19 agricultural resources, which are food and clothes. hence, modern techniques and technologies always do come up with the best solution for higher productivity and quality of cash crops like wheat, rice, cotton, sugar-cane and vegetables [1]. for enhanced productivity with low cost, a wireless sensor network (wsn) provides a variety of solutions for realworld challenges. wsn has proved its significance very effectively in various other applications like structural and health monitoring of highways and buildings, habitats and irrigation [2]. meanwhile, wsn can also be equally beneficial in precision agriculture for monitoring the quality parameters of the crops and helping the farmers and landowners in cultivation procedures as well [3]. a management framework in which suitable strategies and plans based on information and communication technologies (ict) are made to handle the agricultural practices is called precision agriculture or precision farming [4], [5]. the impacts of precision agriculture on improving crop profitability are addressed in [6]. the principle aim of precision agriculture is to increase crop productivity and quality and reduce the efforts of the farmers using ict systems and algorithms [7]. precision agriculture is somehow related to data monitoring of an agricultural field [8]. typical attributes of precision agriculture are [7], [9]: • monitoring of agricultural environmental parameters. • appropriate set point for data collection. • data transmission from source (field) to destination (sink). • control actions and decision-making as per sensed data. in this paper, we portray novel deployment architecture of smart agriculture, which depicts the shape of future digital agriculture. the architecture is comprised of various key technologies, for example, renewable energy sources, sensor classifications, and other emerging technologies. we also provide a detailed discussion on different sensors and sensing technologies is carried out. later, we perform a case study on the wheat crop. in which, we design a wsn-based system to monitor the three most key parameters (temperature, light, and water level). in last, we discuss the research gaps in this study, which can be implemented in the forthcoming paper. the readers and researchers can also integrate our suggested research gaps in their work. the remaining sections of the paper are described as follows: section 2 describes the previous research work based on wsn that had been carried out by different researchers. section 3 gives the details about the term smart agriculture followed by different sensors and sensing technologies. in section 4, we describe the general block diagram of the system followed by the complete picture of the sensor node with iris mote and deployment scenario. section 5 gives the software implementation description, which is also divided into two sub-sections: implantation in tinyos and implementation in ms visual studio. the deployment results are discussed in section 6. section 7 is based on general discussions, for example, the requirement of wheat crops, different users, and future directions. conclusion is given in section 8. exhaust research work on wsn-based precision agriculture has been carried out by different researchers. most of the research work on precision agriculture is based on various application scenarios like agricultural monitoring, data monitoring, greenhouses, pest detection, soil monitoring and irrigation management [5], [8], [12]–[18] by incorporating different methodologies, techniques, tools and platforms [19]–[21] along with basic guidelines [22]. in [23], a wsn-based system was developed for monitoring the fluoride-affected area. their system enables the users to access the status of fluoride sensors at the remote station on their cell phones via the internet. government organizations and ordinary people can also make use of their systems to monitor the affected areas. nowadays, mobile devices such as robots and drones are engaged in agricultural monitoring. wireless sensor networks-based smart agriculture sensing technologies, application and future directions (pp. 18 32) sukkur iba journal of emerging technologies sjet | vol. 5 no. 2 july – december 2022 20 in [14], wsn-based aerial robots were employed. aerial robots were dedicated to vineyards for frost monitoring. the core task of the aerial robot is to provide dynamic mobility to the nodes in vineyards for sensing and creating a communication link between the base station and scrubby clusters sited at disjointed points. their system is very suitable for such areas where wireless sensor networks have some limitations for such characteristics. by using the dedicated communication channel, data can be routed even at long distances. in [13], an instrumentation setup has been made for monitoring the critical inputs of wheat crops such as water and nitrogen. their system was employed for collecting field data continuously. besides, agricultural environmental monitoring, a suitable irrigation plan is also needed for precision agriculture [9]. providing an adequate amount of water in meantime plays a dramatic role in improving crop quality and quantity. in addition, some basic guidelines must be considered before the deployment of wsn in an agricultural field and useful descriptions, such as sops (standard-operating-procedures) of a crop must be reviewed for proper crop monitoring and pre-and-post processing actions. in [22], authors have reviewed different existing components of wsns for precision agriculture, viz. mote platforms, sensor types, operating systems, communication issues, maintenance, power supply, etc. after a deep review of these data, basic guidelines have been proposed for the deployment of wsns in any application scenario related to agriculture. in [16], authors have performed real-time deployment for monitoring the agricultural land. they have designed a wsn system based on iris motes to monitor the humidity, temperature and light intensity. tinyos and ms visual studio were used to program the iris motes and a gui tool for displaying the results respectively. in [17], authors have carried out two operations for agricultural monitoring. firstly, they designed an irrigation system for watering agricultural land automatically. then after, they designed a system to sense the key parameters, potassium (k), nitrogen (n) and phosphorus (p) for improving crop quality and quantity. their system was managed via an arm 7 processor and the monitored data were sent to the remote station with the aid of iot (internet of things). in wsn algorithms can improve the data packet transmission efficiency by up to 25% and also helps to prolong the lifetime of wireless sensor networks to achieve efficient data transmission [49]. in [50], authors provided a survey of tending resource-efficient and secure techniques used with distributed estimation algorithms over wsn. in [39], authors have performed a short survey on the implementations and usage of artificial intelligence in smart agriculture. in addition, various machine learning techniques for smart agriculture are also discussed. some other survey papers related to smart agriculture can be found in [41], [42], in which, the authors have discussed different challenges and proposed some solutions to be faced in smart agriculture. fig. 1 portrays the smart agriculture deployment architecture equipped with modern techniques, paradigms, and technologies in order to provide strong technical support in speeding the agricultural transformation and development [30]. the smart agriculture system collects the key information from the cultivated field via sensing and communication devices [31]. the key information includes soil ph, soil moisture, humidity, temperature, water level, and so on (more classifications of agricultural sensors are given in table.1). agricultural production increases by continuous monitoring of these parameters [31]. the smart agriculture system requires immense quantities and different types of sensor nodes to cover the whole field. these sensor nodes are tiny in size with limited battery power [32]. so, whenever the battery of these nodes is depleted, they halt the sensing operation, and the network lifespan is shortened. hence, it is essential to provide a continuous supply of energy to the smart agriculture system, for which it would be better to opt and energy harvesting techniques wireless sensor networks-based smart agriculture sensing technologies, application and future directions (pp. 18 32) sukkur iba journal of emerging technologies sjet | vol. 5 no. 2 july – december 2022 21 for avoiding the battery depletion of these low powered sensor nodes. fig. 1. deployment architecture of smart agriculture. there are various energy harvesting techniques, such as solar, wind, thermal, vibrations, radio frequency (rf), water, and so on [33]–[35], [40]. the on-board field information collection and consequent actions are the great challenges in agriculture. the data collected from a large field or crop monitoring requires extensive time and effort. for example, performing soil analysis with crop and environmental monitoring requires regular field trips or even multiple times for certain crops. this is highly exhaustive as it requires too much time and manpower along with expenditures to collect the sample and onfield data. thus, thanks to the sensing technologies, which collect the field data and monitor the crops by providing comfort to the farmers. there are several sensing devices and kits in hundreds of thousands and are available in different taxonomies. these sensor taxonomies include [38]: i) measurement, ii) technology, iii) material, iv) operating principle, v) conversion techniques and vi) application areas. we classify the agricultural sensors into these groups i) chemical, ii) physical, and iii) mechanical. table 1 includes an additional breakdown of these sensors. 3.1.1 sensing technologies sensing technologies experience explosive creativity, activities, exciting applications, and innovations in the agricultural sector. various technological firms and entrepreneurs show their diversity and willingness to enter a gigantic field of agriculture. here we discuss some sensing technologies along with their extensive products and their sensory role in the agricultural sector. table 1 provides a review on different agricultural sensing technologies. table i. agricultural sensors classification class type classification chemical sensors ph sensor soil and water quality monitoring biosensor glucose and acids gas sensor pollution and air quality wireless sensor networks-based smart agriculture sensing technologies, application and future directions (pp. 18 32) sukkur iba journal of emerging technologies sjet | vol. 5 no. 2 july – december 2022 22 physical sensors temperature sensor soil, plant, crops, and environment humidity sensor soil and environment watermark sensor soil humidity rain sensor environmental monitoring electrical conductivity soil monitoring leaf wetness sensor tress, crops, and plants terrestrial sensor weather and environmental monitoring color sensor nutrient monitoring passive infra-red environmental monitoring underwater sensor salinity, solvents, and quality underground sensor soil compaction and moisture solar radiation crops and plants mechanical sensors pest detector pest and bug detection pressure sensor soil compaction vibration sensor soil and atmosphere wind sensor speed and direction of air motion sensor environmental monitoring water flow sensor irrigation water level sensor ground and underground 3.1.2 libelium smart agriculture xtreme [58] this smart agriculture tool kit offers numerous onboard sensors developed by libelium. this kit allows various communication protocols, e.g., lorawan (long range wide area networks), wi-fi (wireless fidelity), zigbee, sigfox, and 4g. this smart agriculture xtreme seeks a variety of applications based on iot, for example, precision farming, greenhouses, weather station, and irrigation. the main advantage of libelium kits is that they are solar powered. 3.1.3 smart pot [51] parrot pot has introduced a smart pot, especially for indoor farming within an in-situ bluetooth communication module. this smart pot is also a suitable ingredient for greenhouses and urban farming. various sensors are embedded in this smart pot, for example, sunlight, soil moisture, temperature, and fertilizer levels, which help in continuous monitoring of the plants. 3.1.4 open garden platform [52] open garden platform has capabilities to monitor three different setups: 1) indoor farming (greenhouse and vertical farming) 2) outdoor farming (crops, gardens, etc.), and 3) hydroponics (water sensors). the open garden platform can be equipped with multicommunication modules, such as 3g, wi-fi, or gprs module. the sensed data can be propagated via any of these communication protocols. the indoor/outdoor setup kits include temperature, humidity, light levels, drip (indoor) / sprinkler (outdoor) water pumps, and so on. the hydroponics kit includes many water sensors: moisture, humidity, conductivity, ph, growing light, oxygen pump, etc. 3.1.5 x-ray computed tomography [54] x-ray computed tomography (ct) has the capabilities to examine water content, conductivity, and configuration of the soil by using images. in [56], authors have used x-ray ct images to quantify the hydraulic conductivity of bulk soil. another work using ct images was reported in [57] to airand water-filled pore space and structure of the wireless sensor networks-based smart agriculture sensing technologies, application and future directions (pp. 18 32) sukkur iba journal of emerging technologies sjet | vol. 5 no. 2 july – december 2022 23 soil. in [55], a novel work on x-ray ct and image processing was reported to calculate the root-water absorption in the soil. 3.1.6 the arable mark [59] the arable mark has designed an irrigation management kit for smart agriculture. farmers can use this tool to irrigate their crops properly and precisely. this tool acquires the field data, such as soil moisture, crop water scarcity, and precipitation in order to provide the required water to crops. this helps in avoiding overand under-irrigation. 3.1.7 greeniq [61] the eastern peak provides an agricultural field device for irrigation purposes and is named greeniq. this is suitable for greenhouses and house gardens. it irrigates the gardens using a sprinkler controller. 3.1.8 grofit climate monitoring system [60] the grofit introduced this system for agricultural climate monitoring, it offers a bluetooth based monitoring system with a propagation area of up to 200 meters. this can measure air humidity, temperature, and solar radiation. grofit also provides a cloud to access information related to their devices. 3.1.9 meteohelix iot pro [63] the allmeteo designed meteohelix iot (internet of things) pro hardware, especially for agricultural environmental monitoring based on iot and wsn. it offers a broad number of sensing parameters, for example, solar radiation, rain gauge, pressure, pollution, dew, humidity, temperature, and so on. this is only suited for terrestrial monitoring. this greatly helps in solving the meteorological solutions. 3.1.10 sky-lora weather station [64] farmers can use this weather station kit to forecast any uncertain environmental and weather occurrences, such as rain and wind. this tool kit uses the lora communication protocol to communicate with the master sensor node. its communication coverage is approximately 600 m. 3.1.11 ec1 speed controller [65] this device performs its operation upon monitoring the atmospheric conditions and then toggling the condition of different devices. this controller helps to control various agricultural field devices and equipment by turning on/off the machines. the main system is elaborated in fig. 2. numerous devices come together to make the main system. these devices include iris motes [10], various sensors and a display screen to monitor the data. in this research, our nodes are connected wirelessly in a way of direct topology to communicate with the sink located at the base station. each iris fig. 2. block diagram of the system wireless sensor networks-based smart agriculture sensing technologies, application and future directions (pp. 18 32) sukkur iba journal of emerging technologies sjet | vol. 5 no. 2 july – december 2022 24 fig. 3. complete picture of a sensor node mote is connected to a sensor board. the main control station collects sensed information from individual nodes, which is later on directed to the sink node. mib520cb usb board [11] is used to connect the sink node with the computer via a serial usb port. gui interface is provided for the visualization of measured data to users. 4.1 sensor node with iris fig. 3 shows the complete picture of the sensor node with its peripherals. its peripherals include iris motes [10], mda100cb board [25], temperature sensor [26], ldr sensor, water level sensor and drive circuitry. for this work, three sensor nodes are used, which are wirelessly connected via direct topology with a sink or base station with the aid of iris motes. sensor nodes can acquire temperature, ldr and water level data of irrigated wheat fields. the base station is connected to a computer, where acquired data is monitored and stored in a database for post-processing aspects. batteries keep the sensor nodes alive till the work is done. 4.2 deployment of nodes we performed the deployment of sensor nodes in an agricultural field of the wheat crop (see fig. 4). fig. 4 shows the real-time deployments of the sensor nodes. the sink was about 50-60m away from the sensing field, while sensor nodes were placed at a distance of about 20-30m from each other. fig. 4. physical deployment site of sensor nodes we deployed various sensor nodes consisting of temperature, ldr and water level sensors to sense the agricultural data of wheat crops. experiments were conducted for 10 (ten) weeks, consecutively to obtain the results from the sensing field. the nodes transmit the sensed data via direct topology [15], [28]. the sink node is directly connected with all nodes for access to the sensed data. 5.1 implementation in tinyos a small operating system named tinyos [24] is used to program the iris motes by interfacing the mib520 interface board with a wireless sensor networks-based smart agriculture sensing technologies, application and future directions (pp. 18 32) sukkur iba journal of emerging technologies sjet | vol. 5 no. 2 july – december 2022 25 computer via serial communication. the code for iris motes is developed in the nested c language. despite being a small linux-based operating system tinyos comes with various built-in applications, which makes the programming of iris motes much easier. we programmed four iris motes, one for the base station (as a sink) and the other three for the sensing field (as a sensor node). each iris possesses a unique id. the programming flowchart for sink and sensor nodes is depicted in fig. 5. the sink node is serially connected to a computer/ laptop with the help of mib520cb programmable board. the data is displayed in a gui tool and in the meantime stored in a database so that users can easily observe the measured data. whereas, sensor nodes are deployed at the field site (as shown in fig. 4). once the sink nodes receive the data from sensor nodes, it will display that measured data on the gui tool. the sensor nodes measure the temperature, ldr, and water level of the wheat field and then each sensor node transmits the measured data to the sink node using direct topology. sink nodes and sensor nodes can communicate with each other via a wireless medium. 5.2 implementation in ms visual studio the main gui tool (refer to fig. 6) is developed in microsoft visual studio [29]. the purpose of designing the gui tool is to display the measured data of each sensor of each node. in the gui tool, all three sensor nodes are recognized with node id and three sensors (temperature in degrees celsius, ldr in light/dark (in form of lux in the database) and water level in inches). the data received by the sink node from the sensor nodes are sent to a computer for display on the gui tool through serial communication via a usb port. at first, gui is loaded, in which default values are displayed then for receiving the measured data, the sink node must be interfaced serially via mib520 usb interface board with pc by initializing the port on which it is connected. after the initialization process, the measured data of each node is displayed on the gui tool and updated into the database accordingly. the database can be imported into the data log window by clicking the button to display the data log available on the gui tool. the database can also be viewed in ms access: an office application. this system has been deployed in the irrigated (shallow-water based) wheat field for monitoring three different agricultural parameters (temperature, light and water level). the deployment results are depicted in fig. 6. fig. 6a. shows the temperature measured by three different sensor nodes located at different points in the wheat field (refer fig. 4) for consecutive 10 (ten) weeks. 6.1 temperature measurement fig. 6b shows the comparison between the two temperatures i.e. one is the actual temperature (i.e., standard temperature) of the deployment location and the other is the measured temperature by the sensor nodes. it is obvious that the average temperature as measured by the sensor nodes should be equal to the actual temperature. well, a minor difference in readings is also acknowledged, this difference might be accorded due to different issues, such as power consumption and the distance between the sink node and sensor nodes. it is seen that the average difference between the two mentioned temperatures is 3-4 degree celsius. this difference can be reduced and more accurate and reliable results can be obtained if the temperature sensors are calibrated properly and by minimizing the interferences, network issues, etc. wireless sensor networks-based smart agriculture sensing technologies, application and future directions (pp. 18 32) sukkur iba journal of emerging technologies sjet | vol. 5 no. 2 july – december 2022 26 fig. 5. flowchart for sink and sensor nodes wireless sensor networks-based smart agriculture sensing technologies, application and future directions (pp. 18 32) sukkur iba journal of emerging technologies sjet | vol. 5 no. 2 july – december 2022 27 (a) temperature measurement (b) temp. measurement (actual v/s measured) (c) li measurement (d) li measurement (actual v/s measured) (e) 1st irrigation (f) 2nd irrigation (g) 3rd irrigation fig. 6. deployment results 6.2 luminous intensity (lux) measurement fig. 6c describes sunlight detection in terms of luminous intensity (li) for 10 consecutive weeks. we measured the li during day time because there is no sunlight at night. it is measured in lux. the li is very necessary for crops to complete the process of photosynthesis [27]. hence, the crops are dependent on sunlight for their growth. different states of sunlight at different moments are mentioned in the form intensity unit lux in fig. 6c. fig. 6d. shows the comparison between measured li versus actual li. 6.3 water level measurement fig. 6e, fig. 6f, and fig. 6g plot the water levels of wheat crops at different instant of times for 3 consecutive irrigations. we can observe that the readings for water level for all sensor nodes are different from each other with the passage of time; this is due to the rough surface layer of the wheat crop field. henceforth, by measuring water level, we can irrigate our crops accurately, precisely and timely. moreover, it also helps in avoiding over and under irrigation. thus, an ample amount of water can be saved. we provide a summary of the wsn-based smart agriculture application for wheat crops, which is given in table. 2. wireless sensor networks-based smart agriculture sensing technologies, application and future directions (pp. 18 32) sukkur iba journal of emerging technologies sjet | vol. 5 no. 2 july – december 2022 28 table ii. summary of the wsn-based smart agriculture application for wheat crops # parameter module description remarks 1 pre-deployment input budget = good outdoor crop = wheat period = 10 weeks area = 100m2 node density = 4 random deployment ample amount is available land/field one crop season 1 sink node and 3 sensor nodes 2 sensors input temperature water level ldr 3 hardware and software input sink/sensor node = iris motes mda 300 water level sensor ldr os=tinyos different applications temperature sensor for irrigation for sunlight detection linux based od 4 communication communication topology = tree, direct data rate = 1 message/30sec node-node = zigbee node-sink = zigbee bs-server = wifi server-user = internet also depends on the deployment area application specific 5 energy input rechargeable batteries can be replaced easily 6 safety and maintenance output plastic casing security cameras few can be used across the field 7.1 requirement of wheat crop the wheat crop essentials and requirements are described in fig. 8. according to it, the major requirements for the crops like wheat are temperature, sunlight and water. so far, by keeping these parameters under consideration; the production rate and crop length can easily be estimated. if all or any of these significant parameters become less/more and are not maintained at their proper time, it will directly affect the production and quality rate of the crops, which is further clarified in fig. 8. for further assistance and guidance, different wheat researchers have provided the wheat crop sops (standard-operating-procedures), for example, season, crop length, irrigation period, harvesting time, and so on [62]. 7.2 users there are two major users for the analysis of the results obtained during this work and that are farmers and researchers (or experts). the prime goal of this work is to provide essential up-to-date crop data and information to the farmers, landowners and researchers. wireless sensor networks-based smart agriculture sensing technologies, application and future directions (pp. 18 32) sukkur iba journal of emerging technologies sjet | vol. 5 no. 2 july – december 2022 29 fig. 7. wheat crops essentials farmers: these are the principal and main users of this system. in pakistan, the farmers are either uneducated or have little education. that’s why in this system a simple gui tool is used to display the results. by this, users can easily understand the results and take necessary actions accordingly. experts: the other users of this system might be highly professionals or agricultural experts. these people belong to research or agricultural training institutes. they can analyze the data in form of graphs, charts or statistical views. that’s why, the results are also provided in form of charts and graphs, according to the need of the user. 7.3 future directions sensor network technology is growing day by day, and numerous platforms and tools are introduced to minimize and reduce human interactions and contributions. this research work can be enhanced by using some/any of the following fields. 7.3.1 wireless platforms we can implement different sensor network platforms, such as, wasp mote platform [19], libelium platform [19], fleck platform [5] and other platforms [5], [20], [21] for future correspondences. 7.3.2 sensors there are various other sensing devices, like physical sensors (humidity sensor, soil moisture, watermark sensor, and leaf wetness sensor), mechanical sensors (flow sensors, injectors, and valves) and chemical sensors (biosensor, gas sensor) available in the market [38]. by incorporating these sensors, this work can easily be enhanced. 7.3.3 dynamic controller in this research, we haven’t used any sort of dynamic (mechanical) controller. dynamic controllers are helpful to perform mechanical tasks such as sprinklers, irrigation monitoring, water flow control using valves, injection of pesticides, vibrators and so on [7], [8], [15]. 7.3.4 networking in the wireless sensor network field, networking plays a pivotal role in all application domains in which a different number of sensor nodes are being employed. the researchers and application designers decide the networking according to the application and requirement scenarios. classical networking (star, tree, p2p, mesh, bus topologies) [5], [7], [28], [44], opportunistic networking [3], [5], [45], and cognitive radios [46] are different classes of networking. drones can also be used for networking purposes, such as measuring, intruder detection, and localization [43], [66], [67]. in this paper, we presented various sensing technologies that enable smart agriculture. in addition, we have performed a case study on wheat crops. this work aims to minimize efforts and problems, which are being faced by the farmers while cultivating their crops. this work is based on the real-time deployment of sensor nodes in an irrigated wheat field. we use iris motes as the wsn platform for wireless sensor networks-based smart agriculture sensing technologies, application and future directions (pp. 18 32) sukkur iba journal of emerging technologies sjet | vol. 5 no. 2 july – december 2022 30 incorporating as a sink and as sensor nodes. the iris motes were programmed in tinyos and equipped with temperature, ldr and water level sensors to measure the field data. we measured these parameters; because, the cropped length has been estimated by analyzing the temperature and ldr parameters and by measuring water level, over-irrigation can be avoided. meanwhile, the measured data is transmitted as a base station accordingly. where measured data is displayed, and analyzed on a gui tool, which is developed in ms visual studio 2008. the results can easily be understood by every user without concerning any research expert. the database is used to maintain up-to-date information about collected data from the sensor nodes. this work offers much relaxation to the users for the measurements of required parameters of the crops, their presence at the field site all the time is not required, just once time performs the deployment of the nodes and gets the measured data at their workplace, base station and so forth. acknowledgment the authors appreciate the contributions of quaid-e-awam university of engineering, science, and technology (quest), nawabshah and sir syed university of engineering and technology (ssuet), karachi to execute this work. references [1] ahsan, a., and ahmed, b., ”identification of the type of agriculture suited for application of wireless sensor networks”. russian journal of agricultural and socio-economic sciences, 2012, 12(12). [2] fahmy, hossam mahmoud ahmad. ”wsn applications.” concepts, applications, experimentation and analysis of wireless sensor networks. springer, cham, 2021. 67-232. [3] reyes-yanes, abraham, et al. ”wireless sensing module for iot aquaponics database construction.” international journal of electronics and electrical engineering 9.2, 2021: 43-47. [4] joshi sarang, p., and r. u. chavhan. ”monitoring of agriculture parameter through sensors for productivity enhancement.” new archinternational journal of contemporary architecture 8.2, 2021, pp. 1552-1560. [5] karim, s., and shaikh, f. k., ”wireless sensor network-based smart agriculture.” in opportunistic networking, crc press 2017, pp. 251-276. [6] goel, swati, kalpna guleria, and surya narayan panda. ”machine learning techniques for precision agriculture using wireless sensor networks.” spast abstracts 1.01, 2021. [7] anurag, d., roy, s., and bandyopadhyay, s., ”agro-sense: precision agriculture using sensorbased wireless mesh networks.” in innovations in ngn: future network and services, 2008. k-ingn 2008. first itu-t kaleidoscope academic conference (pp. 383-388). [8] garcia-sanchez, a. j., garcia-sanchez, f., and garcia-haro, j., ”wireless sensor network deployment for integrating video-surveillance and data-monitoring in precision agriculture over distributed crops.” computers and electronics in agriculture, 75(2), 2011, pp. 288-303. [9] singh, i., and bansal, m., ”monitoring water level in agriculture using sensor networks.” international journal of soft computing and engineering, 1(5), 2011, pp. 202-204. [10] habtoor, m.s. and rowaihy, h., ”performance evaluation of iris and lotus motes when communicating in real environments”. international journal of distributed sensor networks, 12(2), 2016, pp.7347158. [11] datasheet mib520. programmable board. http://www.memsic.com/userfiles/files/datasheets/ wsn/6020-0091-04 a mib520cb-t.pdf, (last accessed on febuary 20, 2022). [12] balendonck, j., hemming, j., van tuijl, b. a. j., incrocci, l., pardossi, a., and marzialetti, p., ”sensors and wireless sensor networks for irrigation management under deficit conditions (flowaid)”. in: conference proceedings cd of the international conference on agricultural engineering”. agricultural & biosystems engineering for a sustainable world. eurageng (european society of agricultural engineers). 2008. [13] devadas, r., jones, s. d., fitzgerald, g. j., mccauley, i., matthews, b. a., perry, e. m., and kouzani, a. z., ”wireless sensor networks for insitu image validation for water and nutrient management.” in isprs 2010: proceedings of isprs technical commission vii symposium,. institute of photogrammetry and remote sensing, vienna university of technology, 2010, pp. 187192. [14] valente, j., sanz, d., barrientos, a., cerro, j. d., ribeiro, and rossi, c., ”an air-ground wireless sensor network for crop monitoring.” sensors, 11(6), 2011, pp. 6088-6108. [15] ruiz-garcia, l., lunadei, l., barreiro, p., and robla, i., ”a review of wireless sensor technologies and applications in agriculture and food industry: wireless sensor networks-based smart agriculture sensing technologies, application and future directions (pp. 18 32) sukkur iba journal of emerging technologies sjet | vol. 5 no. 2 july – december 2022 31 state of the art and current trends.” sensors, 9(6), 2009, pp. 4728-4750. [16] rahu, m. a., kumar, p., karim, s., and mirani, a. a., ”agricultural environmental monitoring: a wsn perspective.” university of sindh journal of information and communication technology, 2(1), 2018, pp. 17-24. [17] raut, r., varma, h., mulla, c., and pawar, v. r., ”soil monitoring, fertigation, and irrigation system using iot for agricultural application.” in intelligent communication and computational technologies, 2018, pp. 67-73. [18] toth, g., hermann, t., da silva, m. r., and montanarella, l., ”monitoring soil for sustainable development and land degradation neutrality.” environmental monitoring and assessment, 190(2), 2018. [19] guide, technical, ”agriculture board 2.0”. document version: v4.002/2013, libelium communications distribuidas s.l. http://www.libelium.com. 2013. [20] kusy, b. ”opal sensor node: computation and communication in wsn platforms.” 2012. [21] f. k. shaikh, s. karim, s. zeadally and j. nebhen, ”recent trends in internet-of-things-enabled sensor technologies for smart agriculture,” in ieee internet of things journal, vol. 9, no. 23, pp. 23583-23598, 2022. [22] mampentzidou, i., karapistoli, e., and economides, a. a., ”basic guidelines for deploying wireless sensor networks in agriculture.” in ultra modern telecommunications and control systems and workshops (icumt), 2012 4th international congress on, 2012, pp. 864-869. [23] kumar, k. a., lingam, p. g., and rao, k. m., ”wireless sensor based remote monitoring system for fluoride affected areas using gprs and gis. international journal of computer and technology (ijctt) volume, 7, 2014, pp. 178-182. [24] levis, p., madden, s., polastre, j., szewczyk, r., whitehouse, k., woo, a., and culler, d., ”tinyos: an operating system for sensor networks.” in ambient intelligence, springer, berlin, heidelberg. 2005, pp. 115-148. [25] datasheet, mda100cb, data acquisition board. http://www.memsic.com/userfiles/files/datasheets/ wsn/mts mda datasheet.pdf, (last accessed on febuary 20, 2022) [26] datasheet, temperature sensor. http://www.ti.com/lit/ds/symlink/lm35.pdf, (last accessed on febuary 20, 2022). [27] bareja, b.g., ”what is light intensity, effects on plant growth.” april 2011.https://www.cropsreview.com/lightintensity.html [28] pijl, anton, et al. ”remote sensing vs. field-based monitoring of agricultural terrace degradation.” international soil and water conservation research 9.1, pp.1-10. 2021. [29] powers, l., and snell m., ”microsoft visual studio 2008 unleashed.” pearson education, 2008. [30] n. ahmed, d. de, and i. hussain, ”internet of things (iot) for smart precision agriculture and farming in rural areas,” ieee internet of things journal, vol. 5, no. 6, pp. 48904899, 2018. [31] m. s. farooq, s. riaz, a. abid, k. abid, and m. a. naeem, ”a survey on the role of iot in agriculture for the implementation of smart farming,” ieee access, vol. 7, pp. 156 237156 271, 2019. [32] i. akyildiz, w. su, y. sankarasubramanian, and e. cayirci”, a survey on sensor networks,” ieee communications magazine, vol. 42, no. 5, pp. 102114, august 2002. [33] s. karim, m.a. rahu, a. ahmed, a.a. mirani, g.m. jatoi, ”energy harvesting for water quality monitoring using floating sensor networks: a generic framework.” sukkur iba journal of emerging technologies 1.2, 2018, pp. 19-32. [34] f. k. shaikh and s. zeadally, ”energy harvesting in wireless sensor networks: a comprehensive review,” renewable and sustainable energy reviews, vol. 55, pp. 10411054, 2016. [35] s. zeadally, f. k. shaikh, a. talpur, and q. z. sheng, ”design architectures for energy harvesting in the internet of things,” renewable and sustainable energy reviews, vol. 128, p. 109901, 2020. [36] sivagami, a., pavai, k., sridharan, d., and murty, s.a.v., ”energy and link quality based routing for data gathering tree in wireless sensor networks under tinyos-2. x.” arxiv preprint arxiv:1005.1739, 2010. [37] vijayalakshmi, a., and ranjan p.v., ”code strategy algorithm for online power quality monitoring of electrical equipment using wsn under tiny-os environment.” journal of theoretical & applied information technology 57.3. 2013. [38] white, r. m. ”a sensor classification scheme”. ieee transactions on ultrasonics, ferroelectrics, and frequency control, 34(2), 1987, pp.124-126. [39] f. k. shaikh, m. memon, n. a. mahoto, s. zeadally, and j. nebhen, ”artificial intelligence best practices in smart agriculture,” ieee micro, vol. 42, no. 1, pp. 1724, 2022. [40] f. k. shaikh, m. memon, and s. zeadally, ”simultaneous wireless information and power transfer in internet of things,” energy harvesting in wireless sensor networks and internet of things, p. 223, 2022. [41] b. b. sinha and r. dhanalakshmi, ”recent advancements and challenges of internet of things in smart agriculture: a survey,” future generation computer systems, vol. 126, pp. 169184, 2022. [42] w. tao, l. zhao, g. wang, and r. liang, ”review of the internet of things communication technologies in smart agriculture and challenges,” http://www.memsic.com/userfiles/files/datasheets/ wireless sensor networks-based smart agriculture sensing technologies, application and future directions (pp. 18 32) sukkur iba journal of emerging technologies sjet | vol. 5 no. 2 july – december 2022 32 computers and electronics in agriculture, vol. 189, p. 106352, 2021. [43] i. bisio, h. haleem, c. garibotto, f. lavagetto and a. sciarrone, ”performance evaluation and analysis of dronebased vehicle detection techniques from deep learning perspective,” ieee internet of things journal, vol. 9, no. 13, pp. 10920-10935, 2022. [44] bayrakdar, muhammed enes. ”employing sensor network based opportunistic spectrum utilization for agricultural monitoring.” sustainable computing: informatics and systems 27 (2020): 100404. [45] mathapati, mahantesh, et al. ”a study on secure data aggregation and routing for wireless sensor networks.” international conference on advanced informatics for computing research. springer, singapore, 2020. [46] wang, l. f., and wel, s. q., ”cognitive engine technology”.zte communications, 2, 003. 2009. [47] habtoor, m. s., and rowaihy, h., ”performance evaluation of iris and lotus motes when communicating in real environments”. international journal of distributed sensor networks, 12(2), 7347158. 2016. [48] mythili, v., et al. ”seat-dsr: spatial and energy aware trusted dynamic distance source routing algorithm for secure data communications in wireless sensor networks.” cognitive systems research 58, 2019, pp. 143-155. [49] swami durai, senthil kumar, balaganesh duraisamy, and j. t. thirukrishna. ”certain investigation on healthcare monitoring for enhancing data transmission in wsn.” international journal of wireless information networks, 2021, pp. 1-8. [50] jia, xin-chun. ”resource-efficient and secure distributed state estimation over wireless sensor networks: a survey.” international journal of systems science 52.16, 2021, pp. 3368-3389. [51] parrot pot: smart pot, https://www.postscapes.com/wirelessplantsensors/, (last accessed december 15, 2021). [52] open garden, https://www.cookinghacks.com/documentation/tut orials/open-gardenhydroponics-irrigation-systemsensors-plantmonitoring.html. (last accessed december 15, 2021). [53] apogee sq-520, https://www.apogeeinstruments.com/sq-520-fullspectrum-smart-quantum-sensor-usb/. (last accessed december 15, 2021). [54] phoenix nanotom 180nf, ge sensing & inspection technologies gmbh, wunstorf, germany https://www.bakerhughesds.com/industrial-x-rayctscanners/phoenix-nanotom-m-3d-metrologynano-ct. (last accessed december 15, 2021). [55] daly, keith r., saoirse r. tracy, neil mj crout, stefan mairhofer, tony p. pridmore, sacha j. mooney, and tiina roose. ”quantification of root water uptake in soil using xray computed tomography and imagebased modelling.” plant, cell & environment 41, no. 1, 2018, 121-133. [56] tracy s.r., daly k.r., sturrock c.j., crout n.m.j., mooney s.j. and roose t. ”three dimensional quantification of soil hydraulic properties using xray computed tomography and image based modelling”. water resources research 51, 2015, pp. 10061022. [57] rogasik h., crawford j.w., wendroth o., young i.m., joschko m. and ritz k. ”discrimination of soil phases by dual energy x-ray tomography.” soil science society of america journal 63, 1999, pp. 741751. [58] ”libelium smart agriculture xtreme”, https://www.libelium.com/iot-products/plugsense/ smart-agriculture-xtreme, (last accessed on febuary 20, 2022). [59] ”arable mark irrigation tool”, https://www.arable.com/solutions irrigation/, (last accessed on febuary 20, 2022). [60] ”grofit climate monitoring system,” https://www.grofitag.com/product-page/grofit-iotdevice-1/, (last accessed on febuary 20, 2022). [61] ”greeniq” https://easternpeak.com/works/iot/, (last accessed on febuary 20, 2022). [62] ”wheat seed production techniques manual”, district agriculture development office, sindhupalchwok, https://www.jica.go.jp/nepal/english/index.html, (last accessed on september 02, 2022) [63] ”meteohelix iot pro”, https://allmeteo.com/agricultureiot-weatherstation, (last accessed on febuary 20, 2022). [64] ”sky-lora weather station”, https://get.pycno.co/collections/allproducts/product s/sky lora-and-wifi-weather-station. (last accessed on febuary 20, 2022). [65] ”ec-1 controller”, https://growlink.com/shop/ec-1/. (last accessed on febuary 20, 2022). [66] i. bisio, c. garibotto, h. haleem, f. lavagetto, and a. sciarrone. ”on the localization of wireless targets: a drone surveillance perspective.” ieee network 35, no. 5, pp. 249-255, 2021. [67] i. bisio, c. garibotto, h. haleem, and lavagetto, ”drone surveillance systemrf/wifi-based drone detection, localization, and tracking: a surve,” aviation cybersecurity: foundations, principles, and applications, 49, 2021. https://www.postscapes.com/wirelessplant-sensors/ https://www.postscapes.com/wirelessplant-sensors/ https://www.bakerhughesds.com/industrial-x-ray-ctscanners/phoenix-nanotom-m-3d-metrology-nano-ct https://www.bakerhughesds.com/industrial-x-ray-ctscanners/phoenix-nanotom-m-3d-metrology-nano-ct https://www.bakerhughesds.com/industrial-x-ray-ctscanners/phoenix-nanotom-m-3d-metrology-nano-ct https://growlink.com/shop/ec-1/ an energy efficient crypto suit for secure underwater sensor communication using genetic algorithm vol. 5, no. 1 | january – june 2022 sjet | p-issn: 2616-7069 |e-issn: 2617-3115 | vol. 5 no. 1 january – june 2022 78 internet of things based transducer application to harness tidal energy from coastal and offshore pakistan suresh kumar1, dr. irfanullah khan2, danish1, alveena aslam1, dr. muhammad imran majid3,4 abstract: this paper aims to transform tidal energy into rotation energy for electricity generation and in the course evaluating sea parameters. this is accomplished by integrating the internet of things with tidal energy off the coast (and in a home environment), which further enhances the capabilities of this prototype project to remotely monitor sea-like parameters to enable energy production using tidal energy. as south korea is transducing tidal energy with a total installed tidal power capacity of above 500mw, pakistan and middle eastern countries can benefit from its vast coastal line. this paper proposes a sustainable design that makes the turbine rotate at high speed. a vertical design is chosen, which is bi-directional. the design of the turbine consists of 3 blades, each occupying a 2 square feet area supported by an iron-rod frame. during the experimentation, an average voltage of 5v was generated, whereas the speed of the turbine generated was 75 rpm. it is the first known attempt of its kind supported by indigenous resources. it is proposed that this type of prototype can be scaled, to the coast to produce electrical energy to meet the energy production needs of the region. keywords: arduino; dc motors; internet of things; sensors; tidal energy; transducers; tidal turbines; underwater technology; wi-fi module. 1 introduction sourcing energy from renewable sources is presently a key subject in modern society [1]. it is known that more than 70% of the earth is covered with water [2]. we can use water as a renewable source for energy extraction. the electricity demand is growing, and global warming also pressurizes human life [3]. ocean energy in many forms is being investigated as a potential source [4]. ocean current energy, tidal energy, wave energy, and off 1dept. of electrical engineering, institute of business management, karachi, sindh, pakistan 2assistant professor dept. of engineering management. 3electrical engineering department, institute of business management, karachi, sindh, pakistan. 4school of engineering, university of warwick united kingdom corresponding author: imran.majid@iobm.edu.pk m.majid.1@warwick.ac.uk shore wind energy are some of them. tidal energy is still considered a new alternative energy type. in pakistan, this energy is still immature it may play a key role soon. this pollution-free source of energy is very cost-effective for generating electricity [5]. the relative motion of the earth, the sun, and the moon can be used to generate tidal energy [6]. the distribution of power by using modern technology (iot-based system) in different ways, can be designated small, medium, and large scales via different renewable or nonrenewable sources. tidal power has enormous potential due to the mailto:imran.majid@iobm.edu.pk mailto:m.majid.1@warwick.ac.uk internet of things based transducer application to harness tidal energy from coastal and offshore pakistan (pp. 78 89) sukkur iba journal of emerging technologies sjet | vol. 5 no. 1 january – june 2022 79 size of oceans and the predictability of tides. the main objectives of the paper are: 1. to demonstrate the concept of tidal energy as a source of green energy for developing economies. 2. to understand measurement parameters above the water surface and below it. 3. to demonstrate the usefulness of this emerging technology for coastal communities (radio beacons, search and rescue nodes, night light, etc.). with a width of one and a half feet and a height of two feet, it can produce enough power. the vertical design of turbines makes the project more predictable to gain most of the force from all sides and mold the turbine in a single direction, even if the tide comes and hits the turbine from any direction. thus, the unique vertical design of the turbine is very suitable for the seashore tides. pakistan has 990 km long coastline. the tidal power is more predictable and reliable than solar or wind energy both of which are dependent on the sun and air which makes it less predictable. another point is that water is denser than air, therefore, tidal energy produces more energy compared with wind turbines. tidal energy is inexpensive to maintain, it doesn’t produce direct greenhouse gases or other waste. the tidal energy transducer could also be installed on the river barrages. to install the tidal energy transducers the selection of existing barrages and search of new areas, where barrages can be constructed across tidal rivers bays, and estuaries. the turbines in the barrage converts the power of tides in a similar way a river dam harness the power of a river. the gates of the barrages gates open when the tide rises. at high tide the barrage gates close, creating a pool or tidal lagoon. there are six existing barrages on the indus river which are: sukkur barrage, kotri barrage, guddu barrage, taunsa barrage, chashma barrage and jinnah barrage. in those barrages the tidal energy transducer could be installed. it is a project that can easily be operated and installed over the long coastal line of the country. for installation, the best possible areas we have assumed to test the project are sonmiani beach, kalamata beach, and seaview karachi. furthermore, it can easily be implemented over the indus river in sindh. 2 literature review kramer et al. [7] used the sensor cloudbased economic project to design water quality monitoring for rural areas. this article describes the whole process of water quality monitoring, embedded design, sensors, and data dissipation procedure. the roles of the government, network operators, and locals in ensuring adequate data dissipation are also discussed. it also looks into the sensor cloud domain. because automatically improving water quality is not feasible at this time, efficient and enhanced technology, in addition to economic practices, is assumed and suggested to improve water quality and public awareness. sun et al. [8] discussed an efficient energy management framework to provide satisfactory qoi in iot sensory environments. in contrast to previous efforts, it is transparent and compatible with lower-level protocols in use, preserving long-term energy efficiency without sacrificing any qoi levels [9]. the new idea of qoi-aware "sensor-to-task relevancy" clearly analyses a sensor's sensing capabilities in the iot sensory environment, as well as the qoi criteria required by a task. [10]. under the constraint of service delay, an energy management decision is made dynamically at runtime as the best option for long-term traffic data [11]. finally, an extensive case study is proposed based on the utilization of sensor networks to monitor water levels. a simulation depicts the performance of the suggested algorithms to demonstrate the ideas and techniques given in this work. 2.1 underwater sensors heidemann et al. [12] suggest wireless data transmission in the deep ocean/sea is the emerging technology used for ocean-based observational structures. the use of underwater sensor networks has made it relatively easy to control pollution, monitor the climate, record instruments, and predict natural disasters. the internet of things based transducer application to harness tidal energy from coastal and offshore pakistan (pp. 78 89) sukkur iba journal of emerging technologies sjet | vol. 5 no. 1 january – june 2022 80 study of marine life is another achievement of using underwater sensors. also, the data collected is utilized to search more and survey different missions. because they cover miles of ocean range, underwater wireless sensing structures are well understood for stand-alone applications. the development of underwater sensor networks is driven by the necessity to sense the underwater world [12]. fixed or mobile applications, as well as short and longrange applications, may all have quite distinct requirements. as a result, such requirements can result in demanding distinct designs. the types of underwater sensor network deployments vary as needed, such as mobility and density differences in areas. underwater sensors structures are often static and attached to docks or tied to the seafloor. 2.2 surface water sensors the framework of water technologies implemented by maroli et al. in [13] showed that the above surface water sensing system is a dynamic wireless network architecture that combines multiple communication technologies and solutions to let people and other things to interact. this advanced technology paves the way for the creation of unique applications for so-called smart ocean weather inspection. in the case of water management, the utilization of above surface water sensors allows for monitoring weather parameters in the ocean, such as pressure air, temperature, and airspeed. the implementation of an above-water sensing system also provides an enabling facility to keep the constant check at sealevel. these essential above-surface water sensors can be valuable tools in this context because they allow multiple technologies to store and analyze data from various real-time sensors. 2.3 review of iot enabling technologies internet of things is assumed to have a strong influence in distinct evolving technologies such as clouds computing, wireless sensor networks security protocols, search engines, big data, web services, embedded systems, and the internet [14]. wireless sensor networks (wsn): it is made up of various sensors that are linked together to monitor various types of data [15]. cloud computing: it is also known as ondemand computing, is a type of internet-based computing that allows computers and other devices to process and share data on demand. it can take many different forms, such as iaas, paas, saas, daas, and so on. big data analytics: it is the process of evaluating large data sets that contain various types of data. big data, for example, can be used to uncover hidden patterns, market trends, customer preferences, and other useful business data. communication protocols: it serves as the backbone of iot systems, allowing for connectivity and application integration. as these protocols enable data exchange formats, encoding, and communication data addressing, they make data exchange over the network easier. embedded systems: it's a type of computer system that combines hardware and software to accomplish specific tasks a microprocessor/microcontroller, ram/rom, network components, i/o units, and storage devices are all part of the system. 2.4 methods of tidal energy extraction following are the five approaches of tidal energy extraction. 2.4.1 tidal barrages tidal barrages are structures that are commonly built over the mouth of an estuary through which all of the water streams flow through the basin [16]. the tidal barrages are equipped with conduit entryways that allow water to flow into and out of the basin [17]. during elevated tide, water stream into the sound, and the water is held back by closing the floodgate entryways as low tide approaches which can be seen in fig. 1. knowing the area's flow extent and working it at the right times of the flow cycle constrains the internet of things based transducer application to harness tidal energy from coastal and offshore pakistan (pp. 78 89) sukkur iba journal of emerging technologies sjet | vol. 5 no. 1 january – june 2022 81 flood doors. when the floodgates are allowed to open during low tide, turbines located at the conduit entryways generate electricity [18]. authors have used this rule to reference a variety of energy extraction methods, including ebb generation, flood generation, ebb and flood generation, pumping, two basin plans, and so on. the advantage of using the barrage technique to generate power over petroleum products is that it reduces greenhouse gas emissions. fig. 1. tidal barrages 2.4.2 tidal stream energy mendi et al. [19] emphasized that tidal power was centered on harnessing the tidal flow and generating energy through potential storage rather than the tidal stream. tidal stream innovations have made huge strides toward in the most recent decade. in uk waters identified with flowing stream energy, extensive exploration is underway. the uk has an objective to accomplish 20% of its power necessity through sea assets. around 40 energyconverting machines are being developed, with prototypes being built in uk labs and waters (irena, 2014) [20]. there are no standardizations for flowing stream energy because it is still a developing technology [21]. however, an assortment of gadgets is being created to utilize the water stream to separate power. however, the effectiveness of each device must be thoroughly evaluated through extensive testing in order to select the most appropriate device for a specific application. 2.4.3 tidal fences in [22], tidal fences are installed within the fence framework. these fences are made up of individual and vertical turbines and are also called caisson. a turning channel blocks the entire flow of water and just lets it pass through these fences. these tidal fences are also used in vast basins. like channels between offshore islands and mainland or two islands, these tidal fences can be installed as shown in fig. 2. as these fences do not require basin flooding, they leave a negligible impact on the environment. these fences are cheaper and easy to install. in barrages, the entire framework is needed to be installed before any electricity production; these fences have vital advantages of being able to produce power as soon as the initial implementations are installed. fig. 2. tidal fences [23]. 2.4.4 tidal lagoons in [24], tidal lagoons are considered the modification of barrages. just like standard barrages, tidal lagoon produces power by conventional hydro-turbine. the difference between tidal lagoons and conventional barrages is that those conventional barrages‟ design used the natural coastal line to decrease the barrages‟ lengths. nonetheless, tidal lagoons require blocking the river without regarding how deep that is. that's why the cost increases considerably. wherever there are high-range tides, a lagoon of low cost can easily be installed. these lagoons cause a little visual impact as they appear like a conventional sea wall at lower tides and are below the high tide mark in water [25]. by using demolished structures and loose clusters found in different quarries, these tidal lagoons can be built. entire debris would be dumped as long as the confined wall is completed. as far as any debris can be used to construct the confined wall, the cost of internet of things based transducer application to harness tidal energy from coastal and offshore pakistan (pp. 78 89) sukkur iba journal of emerging technologies sjet | vol. 5 no. 1 january – june 2022 82 building a lagoon can easily be restricted. by using the cheapest materials, the price of installing these structures can be decreased. this beneficial technique of construction created an opportunity of constructing an artificial reef. for fishes and birds, a small and warm water lake can also be built in middle. they can easily swim around without any interruption and cause harm to turbine sluices. 2.5 tidal energy around the world and pakistan the need to decrease co_2 emissions combined with a slow increase in the price of petroleum, has resulted in a significant increase in interest in tidal energy [26]. today, this energy is increasingly being considered as a viable option for a long-term power source around the world. extraordinary tides can be found all over the world. the pentland firth, scotland; the severn estuary; the aleutians; norway's fjords; the philippines; the straits of messina, italy; the bosporus, turkey; the english channel; indonesia; and alaska and british columbia's waterways are just a few of them. tidal energy has many benefits compared to other sources of energy it is a clean, renewable, sustainable resource that is not utilized in its full capacity. it has huge potential to meet the global growing energy requirements in the current challenging period and in the future. arsalan in [27] studied the gis based approach to analyze the sustainable use of the estimated tidal energy potential in pakistan. they further suggested potential sites and from those sites the energy could be distributed to the metropolitan city in an easy way. pakistan has huge potential for renewable energy production and the severe shortage of electricity due to its heavy reliance on imported fuels [28]. rahem et al. [28] reviewed the alternative sources of energy and their distribution strategies. neil et al. [29] studied the impact of tidal energy arrays in the regions of tidal asymmetry and suggested that that energy extracted with respect to tidal asymmetries will have important implications for largescale sediment dynamics. rauf et al. [30] has overviewed the energy status of pakistan and discussed major aspects of energy sector of pakistan. in their research work they suggested based on the reports from national institute of oceanography reports that 170 km area of creek system of indus delta has a huge potential of tidal energy. in 1967, a large hydroelectric plant was commissioned that harnessed the power of the tides to generate electricity. it generated about 540,000 kw of electricity [24]. according to studies, the european regional waters have 106 areas for separating flowing energy, which would produce 48,000 giga watts of power per year. around 50,000 mw of introduced limit is estimated to be reachable just along the coasts of british columbia. there's also the possibility of extracting around 90,000 mw of electrical energy off russia's northwestern coast, and around 20,000 mw at the inlet or mezen stream and the white sea. table i. highest tides of the ocean on a global scale [31] site country tidal elevation (m) bay of fundy canada 16.2 severn estuary england 14.5 port of ganville france 14.7 la rance france 13.5 puerto rio gallegos argentina 13.3 bay of mezen (white sea) russia 10 penzhinskaya guba (sea of okhotsk) russia 13.4 table 1 shows the height of available tides in some of the regions where tidal power stations could be built. in some of these locations, tidal power plants have already been built, while others are still in the planning stages. table 2 lists the main characteristics of four large-scale tidal power plants that were built after wwii and are still operational [32]. internet of things based transducer application to harness tidal energy from coastal and offshore pakistan (pp. 78 89) sukkur iba journal of emerging technologies sjet | vol. 5 no. 1 january – june 2022 83 table ii. existing large tidal power plants distributions [33]. site country bay area (km2) avg. tide (m) installed power (mw) la rance france 22 8.55 240 annapolis canada 15 6.4 18 jiangxia china 1.4 5.08 3.9 3 system methodology the architecture of the iot-based tidal energy transducer is designed such that the entire structure of the prototype occupies roughly an area of 9 square feet with a height of 5 feet. the turbine structure is based on three blades each of 1x2 feet in size. the turbine is supported by an iron rod which supports the entire prototype and the iot underwater and abovewater sensors. three generators are fixed at the top of the turbine, which is supported by a frame welded to an iron rod. the turbine pulley has a circumference of 25 inches whereas the generator's‟ each pulley has 1 inch of circumference. so, one rotation of the turbine generates 25 rotations of a single turbine. but there are three turbines fixed so each rotates 25 times. it shows, if the speed is increased it will generate more power. furthermore, a potentiometer is fixed to carry out the voltage and current of all three generators combined. as the tide hits the turbine, it moves in an anticlockwise rotation. it doesn't matter if the tide is coming forth or going back, since the design of the turbine is vertical; it makes it always rotate in a single direction. the iot structure is based on arduino atmega328p, the microcontroller, and is programmed concerning the sensors attached. all four sensors, which include turbidity sensor, water flow sensor, ph sensor, and the bme280 (temperature, humidity, and air pressure) sensor, are connected to arduino via a wire, and the microprocessor is supplied 5 volts from a battery fixed at the top. sensors sense the data and send it to arduino then arduino in which the wi-fi module esp8266 is connected, regulates the data, and transfers data to the destination source, which could be a cellphone or laptop connected to the internet. the data on the destination source can be seen by using an application (can be downloaded via play-store). the ph sensor, turbidity sensor, bme280 atmospheric sensor, and water flow sensor are all connected to arduino, as shown in fig. 3. then, to transfer data between the microcontroller and the output source, a wi-fi module is connected to arduino. fig. 3. arduino connected to iot sensors 3.1 architecture of iot based tidal energy transducers all four sensors are connected to arduino, as shown in fig. 4. arduino supplies a voltage of 5 v, and it is linked to a cloud where data is stored. this also works as a source between the output device and the microcontroller. data logger links the cellphone to the arduino. 3.2 tidal energy calculations the energy due to the tidal stream (kinetic energy) and the energy due to the release of the stored water in the basin make up the total tidal energy (potential energy). it is also true that an increase in tidal variations or tidal stream energy leads to a significant increase in energy extraction. following notation are used in this model: 𝜌 the density of seawater ( 𝑘𝑔 𝑚3 ) cp power coefficient internet of things based transducer application to harness tidal energy from coastal and offshore pakistan (pp. 78 89) sukkur iba journal of emerging technologies sjet | vol. 5 no. 1 january – june 2022 84 a the cross-section area of the channel (𝑚2) v current velocity ( 𝑚 𝑠 ) ∈ turbine efficiency p power generated (w) h vertical tidal range (m) þ the density of water 1025 ( 𝑘𝑔 𝑚3 ) g gravity ( 𝑚 𝑠2 ) 1. kinetic energy: the kinetic energy of a stream flow passing through a cross-section at a given velocity is given in (1): 𝑃 = 1 2 𝜌𝑣3 () 2. the turbine's power output, also known as its efficiency "∈" depends on the design of the turbine [19, 34]. the power output for a turbine from these kinetic systems can be obtained by (2) as follows: 𝑃 = ∈𝑣3 2 () 3. potential energy: the potential energy is mainly dependent on the tidal prism of the basin. potential energy obtained due to the stored water can be calculated as in (3): 𝐸 = agℎ2 2 () from (3), it can be seen that the potential energy varies with the square of the tidal range. so, a barrage should be placed in such a location where it is possible to achieve maximum storage head. fig. 4. microcontroller connected to data logger, sensors and power supply 3.3 tidal energy generation design this prototype model enables us to generate electricity using both types of tides, the flood, and the ebb tide. the main advantage of this type of model is that the turbine works in one way does not matter from which side tide is coming. all tides force is utilized to generate another force that would move the turbine in a single direction. three wings have been installed on an area of 2 square feet to get maximum power. the tidal turbine design is shown in fig. 5. the diameter of each turbine wing arc is 3 feet. two bearings are fixed at the two ends of the turbine to reduce the friction force, which provides smooth rotation with no certain friction [35]. the whole vertical design is supported by a pipe of 2 cm diameter, which works as an axis of turbine around which it rotates. it also strengthens the internet of things based transducer application to harness tidal energy from coastal and offshore pakistan (pp. 78 89) sukkur iba journal of emerging technologies sjet | vol. 5 no. 1 january – june 2022 85 entire structure to remain stable during tides striking. this pipe provides a path for the underwater sensors wires so that they can easily be connected to the arduino that is present in the upper box. the upper box holds the bme280 atmospheric sensors, esp2866 wifi module, and an atmega arduino. whereas, the lower box holds three different sensors: ph sensor, turbidity sensor, and water flow sensor, which are connected via wires. three sensors present in a lower box are connected via wires, which go through the axis pipe of the turbine. then, these sensors are connected to the microcontroller. the upper box sensors have the same installation as they are connected via wires to the arduino. the whole structure is based on an iron frame, and the turbine is designed from an iron sheet. furthermore, it is covered with paint to prevent from getting iron rust as the turbine is in constant contact with water. fig. 5. tidal turbine design. the entire design is smooth and friendly for marine life as well. the arc of each turbine wing has a 1-foot length. the lower box is kept into a thin filter so that nothing except water enters the box and harms the sensors. the entire structure heights 4 feet. the lower three feet remain in the sea as the turbine keeps gaining tidal force and underwater sensors keep inspecting seawater. one foot stays out of the water so that the upper water sensors check the required parameters, and the microcontroller stays out of the reach of the water. 3.3.1 above-water sensor the bme280 is a combined digital pressure, temperature, and humidity sensor. it has small dimensions, low power consumption, high precision, and stability that allow the implementation in the forecast, environmental monitoring, altitude detection, and iot application. in this prototype project, the bme280 sensor is connected directly to the microprocessor via wires. both the microcontroller and the bme280 sensor are connected to the upper box. the python programming of the sensor is installed into the arduino. it senses the surroundings and then sends data to arduino, which is connected to a 5v battery. then, the microcontroller sends the data via the esp8266 wi-fi module. this esp8266 wi-fi module is a self-contained soc with an integrated tcp/ip protocol stack that can give microcontrollers access to wi-fi networks. each esp8266 module comes pre-programmed with an at command set firmware. after processing the data is transmitted through a wi-fi module, and is shown at the output application. it can be seen on destination sources such as mobile or laptops. the connection of bme280 sensors is located at the top of the rod so that it can easily inspect the environment without any interruption. along with that, the arduino atmega and wi-fi module are also connected via wires. two dc generators are installed at the upper pulley. these generators are supported by a rubber stripe, which is firmly roped around the generator's pulley and the main pulley to make enough grips for rotation. as the turbine rotates, the generators keep rotating in the anti-clockwise direction. one complete rotation of the turbine makes generators rotate about 25 times. thus, it engenders more rotations in generators making them produce higher power. 3.3.2 underwater sensor the underwater system includes a ph sensor, turbidity sensor mjkdz model, water flow sensor yf-5201 model, and the turbine itself. these three sensors are installed in the lower box just below the turbine. three of them are installed and attached in a way that they can gain maximum input and witness internet of things based transducer application to harness tidal energy from coastal and offshore pakistan (pp. 78 89) sukkur iba journal of emerging technologies sjet | vol. 5 no. 1 january – june 2022 86 most of the seawater inspection. the seafloor is majorly unexplored, so this prototype presents a handful of opportunities to inspect the seafloor. the sensors are programmed with python language. all sensors are attached at the bottom and connected via wire, which goes through the turbine’s axis pipe. the ph scale is a logarithmic scale whose range is from 014 with a neutral point being 7. if values are above 7 it indicates a basic or alkaline solution, and if values are below 7, it would indicate an acidic solution. it works on a 5v power supply and is easy to interface with arduino. the water flow sensor measures the rate of flow of water. this rate of flow of water is measured in cubic meters or liters per hour. this also consumes 5v. the turbidity sensor measures how clear the water is. it indicates the degree to which the water loses its lucidity. the 2 sq feet turbine is vertically attached to the rod, and it rotates anti-clockwise. the bidirectional attitude of the wave doesn’t affect the turbine’s speed as it is vertically designed to accumulate the tide the force of any direction. 4 results and discussion the result and discussion section consist of testing, results, and comparisons. 4.1 testing 1. implementation of iot based tidal energy transducer was carried out at sea view karachi as shown in fig. 6. 2. the whole prototype project was set in the water at a distance of 25 meters into the sea. 3. the entire ironframe was first fitted into the ground, and then the sensors boxes were attached. all the arrangement of microcontroller and sensors was already installed. 4. first, the turbine was locked, and the stability of the project was checked to see if it was stable at sea. after attaching each required part, the turbine was allowed to rotate. 5. with each rotation, the turbine generated electricity. other sensors were fitted in upper and lower boxes. the upper box carried bme280, a wi-fi module, and an arduino atmega. along with that, the upper box also carried a 12volts lead battery. this was supposed to provide a power source to the microcontroller and other sensors. 6. after allowing the project to execute its desired function, the results were carried out. the output of power and sensors data can be seen in table 3. 7. the multimeter fixed at the upper box provided the reading regarding the generation of power whereas the cellphone worked as the destination source for showing outputs of sensors‟ values. 8. the blynk app, which is an android application designed for ultimate outputs of projects on arduino, showed the data of each sensor. 9. in every 5 seconds, the data was collected, thus each time data varied in very small fractions. ph and bme280 sensor did not show much variance in output. however, turbidity and water-flow sensors‟ results varied in some fractions, since each tide hit the sensors at different speeds and allowed water of different turbidity. 10. finally, the implementation of the entire project was carried out successfully, and all desired results were noted down. table iii. energy generation of turbines experiment no at home at sea efficiency power efficiency power 1 10.83 % 1.3 w 33.3 % 4.0 w 2 21.66% 2.4 w 33.8 % 4.17 w 4.2 results after completing the project its inspection, as well as testing, was carried out. the values of various parameters were discovered using the designed tidal energy turbine and internet of things (iot) based sensors, which were installed at the site. the entire prototype was carried into the sea for the test, and it was supported by a thick iron rod. the underwater sensors were installed into a box so that the seawater does not harm the sensors. above water, sensors were right above the structure tightened by an ironframe, and there the battery, internet of things based transducer application to harness tidal energy from coastal and offshore pakistan (pp. 78 89) sukkur iba journal of emerging technologies sjet | vol. 5 no. 1 january – june 2022 87 as well as the microcontroller, was set. all the sensors were connected to the microcontroller by a thin wire and the wi-fi module transferred the data to the cellphone with the help of cloud computing. the entire structure of the prototype was fixed in the sea, and then the experiment was carried out. the test of energy generation of the project was done at the seaview site of karachi, and its inspection was also tested at home to check if all the equipment was working accurately. fig. 6. iot based tidal energy transducer at the arabian sea table iv. environment sensor results obtained from prototype and validated with water quality monitoring system in [36]. exp. no results obtained from the project referred in [36] results obtained from this project ph sensor turbidity sensor temperature sensor ph sensor turbidity sensor temperature sensor 1 8.4 50% 28 ℃ 9.08 60% 27.82 ℃ 2 7.9 50% 28 ℃ 9.38 74% 27.65 ℃ 3 6.5 40% 27 ℃ 9.07 32% 28.02 ℃ the experiment of iot-based inspection of seawater parameters was carried out at sea, as the results are shown in table 3. three different readings were taken in different areas. the time of the three experiments was also different as there was a gap of 20 minutes between each experiment. every time experiment was carried out in real-time and results were noted down at the same time as shown on the output source. the voltage and current generated were calculated by a millimeter fixed at the upper box. firstly, the turbine was tested at home with airspeed provided by a fan. the efficiency of the experiment at home was low, as shown in table 3. due to the low force of air, the turbine rotated at a lower speed, thus, producing lower power. again, when the turbine was tested in the sea, the efficiency turned out to be normal. the tidal force created enormous speed in the turbine and thus it produces power of above 4 watts. the expected power was 6 watts as the generators installed have 6 watts power-producing capacity. it was quite hard to achieve the ideal condition where the turbine can move at an ideal speed. however, the outcome of the turbine in seawater was quite normal as per the expectations. 4.3 results comparison a project based on the smart solution for water quality monitoring systems was designed. using iot, that project enabled realtime water quality monitoring, and the results are given and compared to this project in table 4. internet of things based transducer application to harness tidal energy from coastal and offshore pakistan (pp. 78 89) sukkur iba journal of emerging technologies sjet | vol. 5 no. 1 january – june 2022 88 5 conclusion to seek alternatives of energy resources has always been the need and interest of humans. since humans have always wandered in their surroundings to acquire cheap and reliable energy resources. tidal energy is one such source that requires no big human efforts once the stage is set and starting installation is finished. this energy is present on earth in the form of ocean tides in an unimaginable amount. in pakistan, this prototype project can be utilized to define energy production at a major level leveraging the energy sector of the country. aside from that, this project will inspect the ocean water and its various parameters such as ph, turbidity, viscosity, and water flow after working on deep-sea surveillance by installing iot sensors. the humidity of the air in the surrounding area is also measured. in the future, this project can be designed to improve and enhance more surveillance of the deep sea by calculating and inspecting different parameters using advanced sensors, to make the seawater more sustainable for the surroundings including rechargeable batteries and relay beacons. in short, the whole project is a prototype of the energy generation at a small level that can be transformed into a major tidal energy generation plant. author contribution suresh kumar: conceptualization, methodology, software danish: data curation, writingoriginal draft preparation. alveena aslam: visualization, investigation. dr. irfanullah khan: writingreviewing and editing. dr. muhammad imran majid: supervision. software, validation. conflict of interest the author(s) declare(s) that there is no conflict of interest. references [1] s. r. bull, "renewable energy today and tomorrow," proceedings of the ieee, vol. 89, no. 8, pp. 1216-1226, 2001. [2] f. sultana, "water justice: why it matters and how to achieve it," water international, vol. 43, no. 4, pp. 483-493, 2018. [3] v. r. ravipudi and h. s. keesari, "introduction to renewable energy systems," in design optimization of renewable energy systems using advanced optimization algorithms: springer, 2022, pp. 1-9. [4] a. olabi and m. a. abdelkareem, "renewable energy and climate change," renewable and sustainable energy reviews, vol. 158, p. 112111, 2022. [5] n. sifakis and t. tsoutsos, "planning zeroemissions ports through the nearly zero energy port concept," journal of cleaner production, vol. 286, p. 125448, 2021. [6] m. janssen, "reconsidering a scientific revolution: the case of einstein versus lorentz," physics in perspective, vol. 4, no. 4, pp. 421-446, 2002. [7] s. kramer, c. jones, g. klise, j. roberts, a. west, and z. barr, "environmental permitting and compliance cost reduction strategies for the mhk industry: lessons learned from other industries," journal of marine science and engineering, vol. 8, no. 8, p. 554, 2020. [8] z. sun, c. h. liu, c. bisdikian, j. w. branch, and b. yang, "qoi-aware energy management in internet-of-things sensory environments," in 2012 9th annual ieee communications society conference on sensor, mesh and ad hoc communications and networks (secon), 2012: ieee, pp. 19-27. [9] c. h. liu and y. zhang, cyber physical systems: architectures, protocols and applications. crc press, 2015. [10] l. song, k. k. chai, y. chen, j. loo, s. jimaa, and y. iraqi, "energy efficient cooperative coalition selection in cluster-based capillary networks for cmimo iot systems," computer networks, vol. 153, pp. 92-102, 2019. [11] z. sun, c. h. liu, c. bisdikia_, j. w. branch, and b. yang, "9th annual ieee communications society conference on sensor," mesh and ad hoc communications and networks, 2012. [12] j. heidemann, m. stojanovic, and m. zorzi, "underwater sensor networks: applications, advances and challenges," philosophical transactions of the royal society a: mathematical, physical and engineering sciences, vol. 370, no. 1958, pp. 158-175, 2012. [13] a. a. maroli, v. s. narwane, r. d. raut, and b. e. narkhede, "framework for the implementation of an internet of things (iot)-based water distribution and management system," clean technologies and environmental policy, vol. 23, no. 1, pp. 271-283, 2021. [14] a. al-fuqaha, m. guizani, m. mohammadi, m. aledhari, and m. ayyash, "internet of things: a survey on enabling technologies, protocols, and applications," ieee communications surveys & tutorials, vol. 17, no. 4, pp. 2347-2376, 2015. internet of things based transducer application to harness tidal energy from coastal and offshore pakistan (pp. 78 89) sukkur iba journal of emerging technologies sjet | vol. 5 no. 1 january – june 2022 89 [15] p. s. pandian, k. p. safeer, p. gupta, d. t. i. shakunthala, b. sundersheshu, and v. c. padaki, "wireless sensor network for wearable physiological monitoring," j. networks, vol. 3, no. 5, pp. 21-29, 2008. [16] l. blunden and a. bahaj, "tidal energy resource assessment for tidal stream generators," proceedings of the institution of mechanical engineers, part a: journal of power and energy, vol. 221, no. 2, pp. 137-146, 2007. [17] v. khare, c. khare, s. nema, and p. baredar, tidal energy systems: design, optimization and control. elsevier, 2018. [18] v. khare, s. nema, and p. baredar, ocean energy modeling and simulation with big data: computational intelligence for system optimization and grid integration. butterworthheinemann, 2020. [19] v. mendi, j. k. seelam, and s. rao, "evaluation of tidal stream energy at major tidal inlets of goa, india," ish journal of hydraulic engineering, vol. 28, no. sup1, pp. 403-411, 2022. [20] [20] p. higgins and a. foley, "the evolution of offshore wind power in the united kingdom," renewable and sustainable energy reviews, vol. 37, pp. 599-612, 2014. [21] a. vantoch-wood et al., "national policy framework for marine renewable energy within the united kingdom," merific task, vol. 4, no. 1, 2012. [22] c. vogel and r. willden, "designing multi-rotor tidal turbine fences," international marine energy journal, vol. 1, no. 1 (aug), pp. 61-70, 2018. [23] a. behera, "energy harvesting and storing materials," in advanced materials: springer, 2022, pp. 507-555. [24] k. elliott, h. c. smith, f. moore, a. h. van der weijde, and i. lazakis, "environmental interactions of tidal lagoons: a comparison of industry perspectives," renewable energy, vol. 119, pp. 309319, 2018. [25] d. a. paley, cooperative control of collective motion for ocean sampling with autonomous vehicles. princeton university, 2007. [26] e. s. fu, y. fang, and b. k. horn, "power of ocean: evaluation of blue energy," in 2018 4th international conference on universal village (uv), 2018: ieee, pp. 1-4. [27] m. arsalan, h. fatima, a. khalid, i. zia, and i. ahmad, "harnessing the potential of tidal currents in indus delta creeks for making sustainable and green pakistan," university of engineering and technology taxila. technical journal, vol. 21, no. 1, p. 15, 2016. [28] a. raheem et al., "renewable energy deployment to combat energy crisis in pakistan," energy, sustainability and society, vol. 6, no. 1, pp. 1-13, 2016. [29] s. p. neill, "impact of tidal energy arrays located in regions of tidal asymmetry," in proc. 2nd oxford tidal energy workshop, 2013, pp. 19-20. [30] o. rauf, s. wang, p. yuan, and j. tan, "an overview of energy status and development in pakistan," renewable and sustainable energy reviews, vol. 48, pp. 892-931, 2015. [31] a. gorlov, "tidal energy, northeastern university," ed: boston massachusetts, usa academic press doi, 2001. [32] k. murali, v. sriram, a. samad, and n. saha, proceedings of the fourth international conference in ocean engineering (icoe2018): volume 2. springer, 2018. [33] s. j. kulkarni, "tidal energy: a review," international journal of research, vol. 2, no. 1, pp. 55-58, 2015. [34] x. zhang, y. xiong, s. xie, and h. liu, "opticalfiber-based dynamic measurement system for 3d tip clearance of rotating blades," optics express, vol. 27, no. 22, pp. 32075-32095, 2019. [35] b. akinnuli, o. ojo, o. caleb, and k. okeyedun, "design and simulation of a vegetable shredding and washing machine." [36] s. geetha and s. gouthami, "internet of things enabled real time water quality monitoring system," smart water, vol. 2, no. 1, pp. 1-19, 2016 format template sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 40 , vol. 3, no. 2 | july december 2020 nature inspired optimization techniques: a review for fanets shahzad hameed1 qurratul-ain minhas1, sheeraz ahmed2, asif nawaz3, junaid iqbal4, muhammad shahzad5, naveed jan6 abstract: flying ad hoc network (fanet) is a revolutionary achievement in the class of ad hoc networks to access areas near calamities. the concept of pilot free system takes place in technological advancement and computations. networking advancements introduces unmanned aerial system (uas) while the device that makes this system applicable is known as flying drones or unmanned aerial vehicle (uav). single uav may be employed as individual system, but it is more useful when uavs in a network cooperate with each other. uav deployments are rapid and pliant that reduces the tradition ad hoc network limitations. uav have small operating structure and efficient energy life. advance flight control mechanism makes fanets differ from traditional ad hoc networks. fanets can visualized to play key role where humans are in danger or rescue tasks are too dull or dirty. improving the performance of flying drones leads to ease-of-use for formation of network, high stability and fast deployment. routing and cooperative task allocation of nodes is complex in ad hoc networks. in contrast of the study of traditional schemes, our paper is based on the nature inspired schemes. this review study in on routing protocols of beeadhoc, anthocnet and moth-ant inspired routing. in addition, the overview leads to wild life behavior of hill myna and desert sparrow optimization comparative to other biological algorithms is presented in terms of task allocation and rendezvous cooperatively. biological inspired behaviors trend to know the efficient problem solutions for fanets. keywords: fanet; beeadhoc; anthocnet; moth-ant inspired routing; hmadso 1. introduction fanet is a subclass of vanet that governs the autonomous movement of uav. the application scenarios in fanets are forest fire detection, rescue and search operation, patrolling, traffic and urban monitoring, reconnaissance, agricultural management, environmental sensing and relaying network [1]. the multi uav plays an important role in choosing a networking architecture for best performance. there exist 1 department of electronics, quaid-i-azam university, islamabad, pakistan 2 department of computer science, iqra national university, peshawar, pakistan 3 faculty of electronics, higher colleges of technology, dubai, u.a.e 4 department of mechanical engineering quaid-e-awam university, larkana-campus 5 department of electrical engineering and technology, mns uet, multan, pakistan 6 department of information engineering technology university of technology nowshera corresponding author: shahzadhameed01@yahoo.com mailto:shahzadhameed01@yahoo.com sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 41 shahzad hameed (et al.), nature inspired optimization techniques, a review for fanets (pp. 40 58) different networking architectures proposed and emerged. the basic one is the centralized link communication between uavs and single ground station in a fixed topology in which a ground station is responsible for creating the communication between uavs as well as their coordination movements. the usage of a ground control station (gcs) might results in traffic congestion that accordingly influences the system functionality [2]. qos in the fanet is very important in case of emergency services and data packet delivery ratio and delay are also important factors in fanets domain. flying drones have optimal capacities for covert operations, intelligence, surveillance, target acquisition, preventive noise pollution and reconnaissance. uav can perform long and high precision operations for civilian, commercial and military applications. uavs are designed for long endurance despite harsh weather conditions. due to its high detection, recognition and identification (dri) capabilities and resistance to jamming and interference, it is ideally suited for site protection and civil security. fanets involve fast changing topology, frequent network partitioning (nodes leave or join) and three-dimensional movements. they have self-organizing, self healing abilities which leads the life of wireless network. protocols on the other hand can run in different layers to handle dynamic entering and leaving of nodes. each flying uav in fanets considers as a router to achieve real-time effective communication with advance features of perfect actuators, latest software and best loop principles. with temporary wireless communication setup, only fanets provides quick and real time rescuing service and also provide on demand public safety services. fig.1 shows the design system of fanet that can increase the rescuing chances in natural disaster environments. fig. 1. fanet in disaster environment unpredictable event like wildfires occurs in timberland areas (forests and prairies) and could also happen in urban areas (buildings and homes). three possible network architectures proposed for the multi uav system are satellite, cellular, ad hoc and solves or alleviates the problems in direct link approach [3]. networking architecture in fanet established the wireless network among uavs and each uav can perform as a relay node, so that works together in a manner that to forward the packets until it reaches to the target. there are two segments involves according to the communication type. the first one is called "ground or satellite segment" where some uavs directly communicate with base station or via satellite and it is also known as uav-to-infrastructure communication. "aero segment" is the second segment of communication in which the uavs do not have any direct links with the ground station and they are connected with each other. this communication type is known as uav to uav communication. it is important to emphasize that changing in the orientation from using one uav to several small uavs there is a need to develop new networking technologies among uavs. fanet is within that context considered as a popular sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 42 shahzad hameed (et al.), nature inspired optimization techniques, a review for fanets (pp. 40 58) technology for a communication networking for multi uav to extend the operational ambit and ranging, it is also capable of providing quick and reliable response time [4]. the rest of the paper is organized into different sub sections and are describe as follows. section 2 presents literature. section 3 explains the categorization of fanet routing protocols. section 4 presents the biologically inspired algorithms. section 5 presents the simulation analysis of aco, bco, moth-ant and hmadso. section 6 presents the simulation characteristics of these algorithms and at the end this review paper is concluded in section 7. 2. related work routing and handling the resources efficiently among the ad hoc nodes and their cooperative behavior are the key tasks in the field of ad hoc networks like fanets. routing and task allocation can be achieved by picking examples from natural world. based on social behaviors of animal, biological world trend to open up the inspiration interest from wild life. the researchers have been modifying the traditional algorithms to enhance the life time of network, stability period for reliable communication and to reduce path loss and end to end delay. the selection of protocol for routing and algorithm for cooperative task allocation are the complex task in fanets and it depends on the application requirements. all these are depending on total users and their mobility level. the algorithms for routing are used for packet data delivery and are applied to find the best route by mean of secure as well as shortest route for packet sending. now for optimal routes, metrics are defining the selection criteria which may include information of the cost of communication, power consumption, delay, bandwidth, route length (steps number), reliability etc. swarm intelligence (si) so called swarm algorithm is used when external management, coordination and control are not available to solve the complex dynamic problems. bio-inspired protocols anthocnet, beeadhoc and moth-ant inspired routing are efficient in terms of routing as compare to the traditional routing algorithms. further, the algorithm for distribution of different task among nodes to utilize the available nodes efficiently, hmadso is discussed. the concept of algorithm based on biologically inspired in nature is used for problem solution of complex optimization in fanet. nature inspired behavior analyzed by authors [5] and presented the biological concept of honey bee in which bees of the hive categorized into three main groups: i) employed bees ii) onlookers iii) scouts. authors in [6] implemented a bee algorithm for mobile ad hoc networks (manets) for peer to peer file searching and explore the bee behavior. scouting is the first stage which can be further divided into two scouting stages the first one is forward scouting and the second stage is backward scouting. the role of the forward scouts is to scrutinize the network for the destination node. information is carried by forward scout that consist of four categories: scout id, source node id, minimal residual energy and number of hops. a moth-inspired routing algorithm for mobile networks is presented in [7] to improve the communication performance. this protocol can reduce the packet loss and improve the throughput under certain conditions. further, it has choice to know the non-optimal routing path and analyze to reduce the delay and network overhead. some routing protocols of other kinds of ad hoc networks have been modifying for applicability in new ad hoc family (fanets). these routing protocols are classified into six different categories [8]. fanets are high speed data transfer, high nodes mobility and hence not easy to find the universal problem solution of routing and task allocation in fanet. categorizations of routing protocols for fanets are describe as follow. sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 43 shahzad hameed (et al.), nature inspired optimization techniques, a review for fanets (pp. 40 58) 3. catogarization of fanets rouitng protocols categorization of routing protocols and its applicability in fanets are describes as follows 1) static routing protocols 2) proactive routing protocols 3) reactive routing protocols 4) hybrid routing protocols 5) geographic/ 3-d routing protocols 6) hierarchical routing protocols. 3.1. static routing protocols static type protocols hold the static tables, these tables are computed and laden once at the starting of time operation and cannot be updated during task operations. static protocols are not scalable and cannot handle the fast-dynamic topology changes in fanet but useful in academia interest. 3.1.1 data centric: data centric routing presented depended on content of data and can be used for one to many communication models. this is best for cluster topologies where broadcasting can be done by cluster head (ch) to other nodes in the cluster. chs are responsible to extend the reliable communication distance. 3.1.2 multi level hierarchical routing (mlhr): based on cluster topology mlhr proposed in [9] and solved the large-scale scalability problems in vehicular networks. in fanet multiple uavs can be grouped to form clusters in which ch has the ability to link outside cluster. ch is responsible to disseminate data to another uav in cluster. in fanet speedy change of ch enforce large overhead in network. 3.1.3 load carry and deliver (lcad): lcad proposed in [10] in which node at the ground is responsible to pass the required information to uav which securely carry it to destination. lcad has higher throughput but data delivery delay is longer due to use of single uav. maximum throughput and ensure the security are its objectives. 3.2. proactive routing protocols proactive routing protocols (prps) contains the table of route knowing the information of network nodes. these protocols store the route data. in prps, nodes maintain its table up to date and contain only latest data of the routes. data is transmitted by sharing control messages (hello, tc) in it and routing procedure is performed by each node without any direction from others. it is important in fanet to maintain the tables up to date at the time of topology changes. on the other hand, overhead and large bandwidths are main limitations in it. 3.2.1 optimized link state routing (olsr): olsr is the most adaptive routing algorithm proposed in [11] for ad hoc networks. at startup, routes are set in it for all destinations and then by property of proactive routing, nodes within the network contain the updated data of the routes. these nodes are responsible to share the topology information regularly to its adjacent nodes by broadcasting the link state costs using flooding strategy. recently some extensions are developed to utilize the features of this algorithm in different application. 3.2.2 directional optimized link state routing (d-olsr): d-olsr is an extension of olsr and proposed by authors in [12]. it differs from olsr in selection of multipoint relays. node in a network measure the destination distance by the help of route table and when found the long distance to the destination it will go on directional antenna thru d-olsr and when the distance to the destination found smaller than it will go back to olsr and performs omi directional antenna. d-olsr has advantage of less end to end delay than oslr. sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 44 shahzad hameed (et al.), nature inspired optimization techniques, a review for fanets (pp. 40 58) 3.2.3 multipath optimized link state routing (mp-olsr): the routing mp-olsr is basically based on olsr and is proposed in [13] to improve efficiency of data transmission using multipath.mp-olsr is an application layer protocol. this protocol obtains extensibility by employing different link metrics and cost function with flexibility. in fanet the applicability of mp-olsr guarantees the qos for data transmission and in addition, to improve qos loop detections and route recovery implemented in mp-olsr. 3.2.4 destination sequence distance vector (dsdv): authors in [14] proposed dsdv that used the sequence numbers to avoid the loops and to trace the best route. based on bellman ford algorithm, dsdv is proposed and uses with minor adjustment of ad hoc networks. two types of packet updates are available in it. the first is full dump and second is incremental. at the time of topology changes the incremental dump packets are sent only. although dsdv slightly reduce the network overhead but large overhead is there because of periodic updates and required large bandwidth for update process which is necessary in topology changes. 3.2.4.1 fisheye state routing (fsr): fsr is a class of prp and authors proposed it in [15]. fsr reduce the overhead by mean of more frequent small table update to the adjacent nodes. the idea for such a case is known as fisheye scope. one of the main disadvantages of this routing is inaccuracy of network where nodes are high mobility and dynamic topology. similarly based on prp, border gateway protocol with mobile extension (bgp-mx) enables inter domain communication in air born networks scenario. it allows high mobility network to stay connected to each other [16]. based on ads-b setup for aeronautical ad hoc network is proposed in [17]. it is a prp and a topology aware protocol, the aim of this protocol is to get rid of the traditional routing beaconing and presented the velocity base next hop selection metric. the improvement of cognitive transfer ratio and reduce the network overhead can be seen effectively. 3.3 reactive routing protocols reactive routing protocols (rrps) are commonly known as on demand routing protocols and these are designed to reduce the prps overhead. in rrp a route is stored in a node when it communicates with each other. further, nature of on-demand assures no periodic messaging for connectivity. due to this property rrps are bandwidth efficient. the process to tracing routes can consume long time and caused high latency. the source and the hop by hop routing are the two cases of rrps. source to destination address is contain in the packet and based on this information intermediate nodes can only forward packets in source routing. secondly, the destination and next hop address contains in second type of routing (hop by hop). in this case intermediate node maintain routing table to only forward data. 3.3.1 dynamic source routing (dsr): dynamic source routing [18] in rrp and usually designed to use in multi hop networks. it permits networks to be self healing, self organizing without requirement of any existing infrastructure. dsr is an on demand routing and scale automatically. the mechanism of route discovery and route maintenance in dsr achieved efficiently. it has advantage to allow choice from many routes to any destination like load balancing. 3.3.2 ad hoc on demand distance vector (aodv): authors proposed aodv in [19]. it is a class of rrp using hop by hop phenomena and can easily adjust in high mobility and dynamic change scenario. it has lower overhead and it can specify unicast routes to destination. next hop information in the network corresponding to each data transmission contain by source and relay nodes. these data packets have only sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 45 shahzad hameed (et al.), nature inspired optimization techniques, a review for fanets (pp. 40 58) destination ip address which overcomes the overhead. to extending standard routing algorithm of open shortest path first which is widely used in wired network the extension manet designated routers (ospf-mdr) is presented for effectively used in wireless [20]. dynamic mobile ad hoc networks on demand (dymo) routing protocol presented in [21] effective route discovery and route maintenance are the goal of this protocol. 3.4 hybrid routing protocols hybrid routing protocols (hrps) over comes limitations faced in prps and rrps i.e. reduce the overhead caused by control messages and decrease the latency comes from startup route discovery process respectively. these types of routing protocols are suitable for large network. in hrp, network is categorized into two different routing zones i.e. intra zone routing and inters zone routing. proactive routing can be performed by using intra zone routing while reactive routing approach using inter zone. hybrid routing set the scheme according to the network properties and effective for manets. however, nodes behaviors in fanet make it complicated to maintain the information accordingly. it is hard to implement in dynamic networks. 3.4.1 zone routing protocol (zrp): using a concept of zones, authors proposed zone routing protocol (zrp) [22]. zones are established by nodes within the entire network. using approach of proactive, intra zone routing maintain routes while data packets are sent out side by inter zone and using reactive approach to maintain routes. this zone based hrp improve the network efficiency in terms of reactive mechanism and also helpful to improve the quality route discover in terms of proactive maintenance. 3.4.2 sharp hybrid adaptive routing protocol (sharp): sharp [23] protocol finds equilibrium between reactive and proactive routing and proactively set the degree to broadcast the route information and also set the degree to discover the route reactively. the working of reactive and proactive routing protocols varies with network properties and one protocol outperforms the other in different network scenario. this protocol is efficient to reduce the overhead, bounding loss rate and effectively handle the jitter. 3.4.3 temporarily ordered routing algorithm (tora): the algorithm namely tora is proposed in [24]. for multi-hop networks, this algorithm is a family of hrp and routes specifically maintain data knowing the adjacent nodes. the purpose of this protocol is to handle the broadcasting of control messages in high mobility scenario and reduced the impact of topology changes. the protocol tora does not follow the shortest route but a longer route is often adapted to reduce the overhead effect. 3.5 geographic 2-d and 3-d protocols geographic schemes consider geographic position of nodes and known the information about nodes. the source in geographic model knows the geographical place of the node and messages are sent to the destination without route discovery. many routing strategies for 2 dimensional networks have been developed by adapting planar geometry. the main technique use for this model is greedy forwarding. the main purpose is to decrease the number of hops and contain only local information. in this way every node pass the data to the node adjacent to the destination. in fanet application it may be more convenient by using 3 dimensions. high dynamic topology changes and high mobility need the 3-d environments to scale the parameters. 3.5.1 greedy random greedy (grg): grg forwarded the message greedily till local minima are encountered. authors in the paper [25] analyzed simulation results of five recovery algorithm and compared them to find the best one. based on sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 46 shahzad hameed (et al.), nature inspired optimization techniques, a review for fanets (pp. 40 58) random walk are on surface, on dual and on graph further are namely bounded dsf on spanning tree and bounded flooding. random walk schemes are best for denser networks while dsf on spanner approach shown effectual performance for sparse networks. ghg is acronym of greedy hull greedy protocol presented in [26] for routing on the hull to escape local minima. the researchers have proposed a protocol namely partial unit delaunay triangulation (pudt). the purpose of this protocol is to split up the network into amount of close sub spaces to handle the local recovery procedure. 3.5.2 greedy perimeter stateless routing (gpsr): greedy perimeter stateless routing (gpsr) presented by authors in [27]. its purpose is to use the data packet and position of the routes to enable data packet forwarding decisions. these decisions are depending on only local information of adjacent in the network topology. whenever greedy forwarding is not possible, this algorithm recovered by routing about the circumference of the area. using the property containing only local topology state, this protocol scales efficient in per router state than shortest path. in high mobility topology changes, gpsr is capable to use local information for tracing the appropriate routes quickly. 3.5.3 location aided routing (lar): authors in [28] presented the concept to utilize location information. idea based on global location system it presented to improve the working of lar protocol for ad hoc networks. by obtaining local information, this routing algorithm limits the search for updated route to a minor request zone of a ad hoc network that caused to decrease number of routing messages and reduce the overhead. 3.5.4 uav search mission protocol (usmp): protocol for uavs proposed in [29] for 2-d searching grid. by combination a searching property like search protocol and usmp, inter uav link having geographic routing produce to improve the search in efficient way like complete search, uav distance, and the minimization of uav direction changes. further, to improve the search efficiency messages are geographically routed by determining where search position updates its search decisions. 3.6 hierarchical protocols hierarchical protocols are the set of routing solutions. these protocols are proposed for problem solution of scalability and overheads. hierarchical protocols are one of the possible routing solutions in fanet. different hierarchy of protocols reduces the network congestion. the hierarchical protocols divided the plan in different levels and routing is performed in these levels. the concept of cluster develops for different target operation areas. each cluster in the selected region has a principal cluster called cluster head (ch) and each node in the clusters are within the range of ch for reliable transmission. ch provides link outside the region with other network for large scale transmission. 3.6.1 landmark ad hoc routing (lanmar): novel based routing namely landmark ad hoc network (lanmar) presented in [30]. this protocol is achieved by combining the characteristics of landmark and fsr routing for ad hoc networks. a data packet within the entire network initially moves in landmark behavior for long distance in terms of division of groups of nodes. in meanwhile when it got near to destination, eventually shifted to fisheye for appropriate route provider. experimental analysis of lanmar results scalable and effectual for large routing ad hoc scenario where group mobility exists. distance routing effect algorithm for mobility (dream) proposed in [31]. the proposed protocol mainly develops from two novel observations of distance and position information. routing table updated with position information of a sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 47 shahzad hameed (et al.), nature inspired optimization techniques, a review for fanets (pp. 40 58) distance function by breakup nodes without disturbing the routing accuracy. table i summarizes the classification of protocols and its applicability for fanets as discussed above. table i. classification of protocols classification of protocols protocols type static data-centric [4] mlhr [9] lcad [10] proactive olsr [11] dolsr [12] mpolsr [13] dsdv [14] fsr [15] bgp-mx [16] ads-b [17] on-demand/ reactive dsr [18] aodv [19] ospf-mdr [20] dymo [21] hybrid zrp [22] sharp [23] tora [24] geographic/ 3-d grg [25] ghg [26] gpsr [27] lar [28] usmp [29] hierarchical lanmar [30] dream [31] 4. biological inspired algorithms it is complex to declare someone universal problem solution of the routing and task allocation in fanet. in [32] researchers used the differential geometry to design the guidance system with a capability of targets tracking and rendezvous with uavs. the concepts of velocity factors and targets of uavs is presented by researches with a mathematical solution. in research paper [33] the design for uavs of a cooperative localization mechanism is presented by using the non-parameterized belief algorithm. the authors consider dynamic variables for task allocation in terms of position of uavs in a predefine ambit. authors in [34] proposed a framework using uavs for cooperative searching. reliability and movement planning are used as determination parameters for cooperative task allocations while governing task performed by the framework with motion planning and their control. unlike traditional networks the study of swarm organizing can be develop from nature. the nature based biological inspired algorithms changed the model of networking in the field of biological behavior for optimal solution. structure of topology algorithm on particle swarm optimization (pso) for fanet proposed in [35]. construction of topology ensured the operation of end to end communication between the ground control station (gcs) and uav. every uav perform the assign job through optimizing the position of relay uavs. proposed algorithm is compared with random structure topology algorithm and as a result, instead of choosing an optimization theoretic approach, pso algorithm got preferred to structure a fanet topology. 4.1. bee colony optimization algorithm the best adaptive algorithm is a bee colony algorithm when deal with topology changes. bee optimization algorithm differs from some conventional routing algorithms used for routing in telecommunication networks. alike to other swarms’ algorithm, algorithm of bee started to collect the data and transmitted to other nodes. fig. 2 shows the bee colony behavior diagram. by nature, the bee hive operational principles are pre-define for allocation of responsibilities among the bees. in figure searching begins by employed bee for a nectar source while in the hive, the other bees (onlookers) are remain and data received only from the employed bees by attracting special "waggle dance". this waggle dance devolves on the sun location. the motion of the bee strongly indicated where precisely food is located. finally scout bee randomly search for new nectar sources. sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 48 shahzad hameed (et al.), nature inspired optimization techniques, a review for fanets (pp. 40 58) fig. 2. bee colony behavior in wild life in [36] checking the scout characteristics of every visited node the conclusion of route efficiency can be draw by the algorithm. the probabilistic calculation is maintained by probability distribution table. this is complex procedures which require several verification steps. such things happen like, if more than one forward scout received by a node. it confirmed it first that either the scout has arrived before or not with help of its id, next important unit is forager-bees come in action after culmination of scout process and route conclusion. the foragers transfer the information like a real bee carries the food. the number of foragers played an important role for the route calculation using dance formula phenomena and then phase of resource foraging started. the procedure of data transmittal is quite complex whenever information is transmitted from one node to the other node and hence vary the amount of forager-bees subject to network condition. 4.2. ant colony optimization algorithm comparative to the traditional protocols for wireless ad hoc network, aco is differs due to its biological environments. fig. 3 shows the behavior of aco algorithm with equal task distribution. the process of food search by ant in wild life can be compared with on demand or reactive component on event calling in communication session. while by definition, proactive component operates periodically to maintain and bring the latest data on the existing routes and to improve connection during communication period. the main difference between these two components is reactive component comes into action only when the existing known routes comes faulty. so when deal with ant algorithm in nature it is just betterment of the route between hill ant and food. fig. 3. initial equal task distribution in aco algorithm formation of possible channels between source and destination using ant behavior or control data packets in communication that gather the routing information using iterative sampling. fig 4 shows the behavior of ant for searching the food in different possible ways in the field. fig 5 shows the optimized route between nest and food which is the shortest one. the technique of creating protecting routes during link break the procedure of route repair is used in fanet for efficiency and reliability of data. all the decision comes from source node while intermediate nodes in aco algorithm made no decisions in routing. intermediate nodes play an important role and store the pheromone tables. in [37] the analysis did perform to know the working and draw nodes capable for decisions making. the foragers did unify and built a single swarm then it come back to the source after completion of appraise. same id of the route for forager can help to performed this. determinations of number of routes at the time of come back and ineffective are eliminated from route tales. sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 49 shahzad hameed (et al.), nature inspired optimization techniques, a review for fanets (pp. 40 58) multi beam antennas network with higher fig. 4. following the field searching food fig. 5. optimized route between nest and food 4.3. moth and ant algorithm peculiar trajectory of the male for light source is due to searching and then it observed the direction of light origin with its natural capability of piercing thermal sensing to locate a direction. the natural behavior of the moth-ant shows in fig. 6. initially it follows a straight line by using dive speed to reach the target quickly. in second step when it senses that the target is near, it slowdowns the speed and cautiously fly in the direction of target and follow the zigzag curve. finally, the moth realized that the source of light is closer than by nature it adopted the circular fly to lock the source. now this model deal in low level routing of the network based on the trail of ant pheromone for maintenance and used to follow the trajectory. hence this scenario minimizes the delay. similarly, ants use striking chemic to put down the trajectory to leave the path to their partner where they can promptly find the source of food such a feature refer to the time decay property. three levels of networks for routing protocols are high level network, low level network and cross level presented in [38] and exploited the directional antennas for multi beam of hierarchical network. considering long space links and high rate of communication a fence routing protocol exploit the effectual benefits in high level of throughput and lower delay in competitive to traditional protocols. moth-inspired routing is capable for low level network with high density and short distance. low rate link overcome the singular mobility of sink in terms of less packet loss and higher throughput than traditional mobile routing protocols. moth and ant behavior have high throughput and low latency. in level routing, this protocol ensures the approaching chance to the commander node situated in high level network using cross level technique. the concept of cross level is in order to deliver packet from low level network to the node in high level network. fig. 6. the behavior diagram of male moth 4.4. hill myna and desert sparrow optimization (hmadso) a new optimization algorithm presented in [39] based on the natural feature for hmadso. hill myna optimization provided effectual route rendezvous. optimization based on desert sparrow optimization provided task allocation cooperatively. localization based on desert sparrow can obtained from cooperative rendezvous. rendezvous permitted suitable solution for the cooperative network formation with high mobility nodes. task distribution cooperatively permitted non-redundant cooperative task treatment among nodes. both these optimization algorithms are sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 50 shahzad hameed (et al.), nature inspired optimization techniques, a review for fanets (pp. 40 58) complementing to each other and hence, are to protect the other birds from a threat decrease the spatial complexities and time related to cooperative problems in fanet. 4.1.1 hill myna optimization for cooperative rendezvous: the hill myna in bio-inspired is similar to uav in fanets. hill mynas are species and have characteristic of common idiom within the range of 15 km. the idiom range of the mynas in nature is similar to the radio range of the nodes in fanet. the route discovery between uav is based on the characteristic of the common idioms. based on its ability for vocal identification it allowed the identification of all the similar species in the entire ambit. by natural ability, these birds do not replicate the vocal qualities which become appropriate and non-equivocal representation. this brings added to free from danger characteristic of hill myna optimization. mynas are sound, clever and precise learning characteristics that added into its lineament. this brings to perform a basic organizing for optimized algorithm. usual dialect feature of this bird helps out the representation of adjacent neighbors in the allocated area for each myna. idiom other than this in the swarm or network distinguishes the availability of another cluster. cluster organizing is carried out upon this vocal representation and idiom strength in a swarm. this precise choice of cluster controller it coordinated the motion and communication guaranteed among the birds. 4.1.2 desert sparrow optimization for cooperative task allocation: as family of bird, desert sparrow has special characteristic of defenders, attackers and protectors. in addition, the capability of this bird permitted the concerted nest building, concerted searching, and identification of neighbor. defenders action while action of counter attackers are performed by attackers and finally stay in the swarm with the younger strength and these are neither attackers nor defenders and are known as protectors. biologically inspired coordination of these birds in various tasks can perform cooperatively. overlapping and ambiguity is reduced by precisely assigning the task distribution and cooperative task allocation among them. during cooperative task operation, each bird knows the position and present level thru which the process is performed by it. hence, during cooperation the feature of making localization is important. desert sparrows are intent at resource distribution rather than utilizations. desert sparrow has a predefined sight range that assists them in identification of attackers. further, protection against opponent creatures, they make them enable to make decisions regarding defense. applying the abilities of desert sparrows, algorithm of cooperative task allocation has been designed. this is actually the integration with hill myna optimization. global problem in the field of fanets are task allocation and rendezvous are solved by this algorithm effectively. dependency of route tracing of each desert sparrow and their control motion optimized in this algorithm. based on s-dac principle this optimization algorithm by mean of survey, decision, awareness, and cooperate. usually this algorithm is a novel concept of understanding between nodes. following necessary steps are required for task operation. at first it started with an initial survey which enables them for courtly decision further, awareness of these decisions to the others are made to secure the swarm and at last cooperation is made for all components to build mutual control. table ii summarizes the algorithms as discusses above and their features and limitations in fanets in comparison of traditional schemes. . shahzad hameed (et al.), nature inspired optimization techniques, a review for fanets (pp. 40 58) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 51 table ii: features and limitations of beeadhoc, anthocnet, moth-ant inspired and hmadso name features limitations bee colony algorithm [36] • better throughput than dsr and dsdv. • may be used in packet routing in fanet. • beeadhoc overhead increase in proportion to the nodes amount. • most adaptive algorithm in rapid topology change fanets. • quickly adjust to the changes with the rate increase and show the best throughput values. • nodes increases cause the increase in the throughput. • alike dsdv and dsr this algorithm is good as routing. • longer delay due to search of new destination. • only slightly effect on throughput. • somehow inferior to aodv and dsr. • not good for task optimization in fanets. beeadhocant hocnet protocols [37] • anthocnet protocol performs efficient in fanets. • this protocol has fine scalability. • throughput increases as number of nodes increases • more effective in contrast to other biological algorithms. • not optimal in terms of throughput. • only used for data delivery routing. • not easy to declare universal routing problem solution. • routing overhead increases as node quantity increases. • lower throughput of dsdv when the nodes amount increases. moth-ant routing protocol [38] • significant throughput as compares to traditional protocols. • smaller updating period brings a higher throughput. • validate the cross-level routing scheme. • it has better scalability. • moths inspired at low speed achieve good performance. • sink speed of moth increase as a result in increase in throughput in low level routing • not good for resource distribution. • not optimal throughput comparative to aodv and dsr. • high packet loss when deal with cross level routing. • task optimization problem remain for fanet. hmadso [39] • hmadso has best performance associated with uavs. • good for cooperative task allocation in fanet. • it can obtain cooperative task allocation and cooperative rendezvous. • time and intricate of cooperative problems in fanets are reduced. • in terms of task handling it is better than aco and bco. • it deals better when nodes are increased in the network. • achieving better cognitive ratio. • it has high network latency. • cannot declare universal problem solution of task allocation. shahzad hameed (et al.), nature inspired optimization techniques, a review for fanets (pp. 40 58) adjustment with the change in the rate increase sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 52 5. simulation analysis of bio inspired schemes with traditional schemes 5.1. beeadhoc, anthocnet: in order to measure the performance of routing protocols, necessary metrics are throughput, end-to-end delay routing overhead. routing is a complex problem in fanets, biological approaches have been describing the routing problem solution for fanets. packet data routing delivery in fanets may be used biological inspired algorithms aco and bco. these are only for routing purpose but not suitable and efficient for task optimization. increase in the number of nodes within the targeted area may increases the throughput of the protocols. bco is the most adaptive algorithm in topology change situation especially its rapid and show the best throughput values. bco has longer delay because of searching the new routes to the destination. anthocnet performed efficiently in fanets environment. this protocol has fine scalability and same as bco the throughput of this protocols increase as number of nodes increases. when the node rate slightly changes in rate, the heavy load due to routing overhead with increase in node mobility remains the throughput level at same position. aco and bco methods appear more effectual in comparative to other biologically inspired methods. bco and aco are used for data delivery and routing but not good for task optimization problems. comparison characteristic of beeadhoc, anthocnet with traditional protocols (aodv, dsdv, dsr) shows in table iii. table iii. comparison characteristic of beeadhoc, anthocnet with traditional protocols. protocols end-to-end delay throughput overhead beeadhoc inferior to aodv and dsr high low anthocnet less than aodv high high aodv high high high dsdv low low high dsr low high high routing overhead increases for all the protocols only when number of nodes in the network increases. dsdv and dsr are under small load when nodes mobility has increased with respect to routing overhead. longer delay in beeadhoc relative to the other protocols due to unnecessary finding of new routes to the destination. an advantage over the other protocols by the throughput became it most popular. better throughput achieved from beeadhoc than dsdv and dsr, but has longer delay. 5.2. moth-ant inspired routing moths inspired at a low speed can achieve better performance due to construction of non-optimal path comparative to traditional mobile routing. moth routing has significant throughput as compare to traditional protocols. sink speed of moth sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 53 shahzad hameed (et al.), nature inspired optimization techniques, a review for fanets (pp. 40 58) increases as a result in increase in throughput with cross level routing. moth-ant scheme in low level routing. antinspired validate the cross-level routing scheme. it has also better scalability but has high packet loss when deal compares with traditional schemes is shows in table iv. table iv. comparison characteristic of moth and ant with traditional schemes. protocols latency throughput delay packet loss high level network (fence routing protocol) low high low low low level network (moth inspired routing protocol) low high low low cross level network (ant inspired scheme) low high low low table. v. comparison characteristic of hmadso with aco and bco. protocols latency cognitive transfer ratio map transfer ratio average task handling hmadso low high high high aco high low low low bco high low low low 5.3. hmadso the analysis of hmadso algorithm in terms of cooperative task handling brings improvement than aco and bco. in fanets increase in the quantity of uav will result in decrease the number of tasks per uav. moreover, increase of uav in network handle more tasks cooperatively but caused high latency. aco offered lowest network cooperation time than bco. in addition, hmadso support good enough cooperation time than bco. however, in hmadso the latency of network operation is higher as compare to aco but lower than bco. whenever the requirements are high packet delivery ratio, map transfer and the network redundancy is required low then hmadso offered the best solution than other bio inspired algorithms but only latency issue remains in this optimization algorithm. cognitive ratio results better in hmadso with increase in number of nodes but has high network latency rather than utilization desert sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 54 shahzad hameed (et al.), nature inspired optimization techniques, a review for fanets (pp. 40 58) sparrow optimization and it is capable for resource distribution. hmadso has best performance associated with uavs network parameters. this optimization is good for task distribution and cooperative rendezvous in fanet. time and intricate of cooperative problems in fanets are reduced by this algorithm. it is better in terms of task handling than aco and bco. only problem with hmadso is its high latency which reduce the impact of such algorithm. if the network requirements are high packet ratio, map transfers and low redundancy of the network than hmadso proved a better solution as compare to other techniques. comparison characteristics of hmadso with aco, bco is shows in table v. 6. simulation characteristics of bio inspired schemes characteristics beeadhoc anthocnet, beeadhoc moth-ant inspired routing hmadso evaluated objectives type single objective single objective single objective single objective criteria end-to-end delay end-to-end delay end-to-end delay latency throughput throughput throughput packet delivery ratio overhead overhead overhead map transfer ratio network cooperation time task handling simulatio n paramete r operationa l area 1500m*1500 m 1500m*1500m (300km*300km) ~ (200km*200km) 5000*5000m 2 simulation runs 10 10 100 simulation duration 20sec 20sec 1000sec uavs 10~50 10~50 25~50 5~30 mobility model random waypoint random waypoint even and singular for high and low level network respectively node velocity 20~100m/s 20~50m/s 0.1~0.3km/s 10m/s traffic type cbr cbr cbr signal propagatio n model friis friis two-ray ground mac layer protocol 802.11 802.11 tdma-like sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 55 shahzad hameed (et al.), nature inspired optimization techniques, a review for fanets (pp. 40 58) data link antenna omni omni multi beam directional antenna coverage range 150~350m 150~350 m <90km transport protocol udp udp packet size 512kb 512kb 1kb 6. conclusion routing and task allocation have unique requirement especially when deal with fanets. aspects may considerable to find the most efficient route, controlling the latency, ensuring the reliability, allowing the network to scale and ensure the quality of service. design of suitable protocols and algorithms in fanet are the complex task due to its high mobility and dynamic changes topology. high node addition and removal behavior still see native protocols in fanet. in this review article we attempt to explain the research area based on biologically inspired algorithms. the reason to undertake this important survey is due to only few surveys focusing on naturally inspired field. we discuss six categories of protocols and see their applicability in fanets. further, different techniques of biologically inspired are discuss and see the extent to which they are suitable for fanets. the routing and cooperation thru biological behaved algorithms provide the way towards the problem solution in fanet. the biological inspired routing algorithms bco, aco, moth and ant inspired routing and in addition hill myna and desert sparrow optimization prove to be efficient algorithms and overcome the problems facing in traditional protocols. simulations based study will be the new consideration in future work with some other biological inspired algorithms. in present review article we focused on issues relating to routing protocols and task allocation based on bio inspired techniques. references [1] bujari, armir, claudio e. palazzi, and daniele ronzani. "fanet application scenarios and mobility models." in proceedings of the 3rd workshop on micro aerial vehicle networks, systems, and applications, pp. 43-46. acm, 2017. [2] bekmezci, ilker, ismail sen, and ercan erkalkan. "flying ad hoc networks (fanet) test bed implementation." in recent advances in space technologies (rast), 2015 7th international conference on, pp. 665-668. ieee, 2015. [3] mozaffari, mohammad, walid saad, mehdi bennis, young-han nam, and mérouane debbah. "a tutorial on uavs for wireless networks: applications, challenges, and open problems." ieee communications surveys & tutorials 21, no. 3 (2019): 2334-2360. [4] gupta, lav, raj jain, and gabor vaszkun. "survey of important issues in uav communication networks." ieee communications surveys & tutorials 18, no. 2 (2016): 1123-1152. [5] karaboga, dervis. an idea based on honey bee swarm for numerical optimization. vol. 200. technical report tr06, erciyes university, engineering faculty, computer engineering department, 2005. [6] dhurandher, sanjay k., sudip misra, puneet pruthi, shubham singhal, saurabh aggarwal, and isaac woungang. "using bee algorithm for peer-to-peer file searching in mobile ad hoc networks." shahzad hameed (et al.), nature inspired optimization techniques, a review for fanets (pp. 40 58) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 56 journal of network and computer applications 34, no. 5 (2011): 1498 1508. [7] nugroho, dwi agung, agi prasetiadi, and dong-seong kim. "male-silkmoth inspired routing algorithm for large-scale wireless mesh networks." journal of communications and networks 17, no. 4 (2015): 384-393. [8] tareque, md hasan, md shohrab hossain, and mohammed atiquzzaman. "on the routing in flying ad hoc networks." in computer science and information systems (fedcsis), 2015 federated conference on, pp. 1-9. ieee, 2015. [9] sahingoz, ozgur koray. "networking models in flying ad-hoc networks (fanets): concepts and challenges." journal of intelligent & robotic systems 74, no. 1-2 (2014): 513-527. [10] cheng, chen-mou, pai-hsiang hsiao, h. t. kung, and dario vlah. "maximizing throughput of uav-relaying networks with the load-carry-and-deliver paradigm." in wireless communications and networking conference, 2007. wcnc 2007. ieee, pp. 4417-4424. ieee, 2007. [11] jacquet, philippe, paul muhlethaler, thomas clausen, anis laouiti, amir qayyum, and laurent viennot. "optimized link state routing protocol for ad hoc networks." in multi topic conference, 2001. ieee inmic 2001. technology for the 21st century. proceedings. ieee international, pp. 62 68. ieee, 2001. [12] alshbatat, abdel ilah, and liang dong. "cross layer design for mobile ad-hoc unmanned aerial vehicle communication networks." in networking, sensing and control (icnsc), 2010 international conference on, pp. 331-336. ieee, 2010. [13] radu, dan, adrian cretu, benoît parrein, jiazi yi, camelia avram, and adina aştilean. "flying ad hoc network for emergency applications connected to a fog system." in international conference on emerging internetworking, data & web technologies, pp. 675-686. springer, cham, 2018. [14] perkins, charles e., and pravin bhagwat. "highly dynamic destination-sequenced distance-vector routing (dsdv) for mobile computers." in acm sigcomm computer communication review, vol. 24, no. 4, pp. 234-244. acm, 1994. [15] pei, guangyu, mario gerla, and tsu-wei chen. "fisheye state routing: a routing scheme for ad hoc wireless networks." in communications, 2000. icc 2000. 2000 ieee international conference on, vol. 1, pp. 70-74. ieee, 2000. [16] kaddoura, maher, barry trent, ranga ramanujan, and gregory hadynski. "bgp-mx: border gateway protocol with mobility extensions." in military communications conference, 2011-milcom 2011, pp. 687-692. ieee, 2011. [17] zhou, qi, wenzhe gu, jinglin li, qibo sun, and fangchun yang. "a topology aware routing protocol based ads-b system for aeronautical ad hoc networks." in wireless communications, networking and mobile computing (wicom), 2012 8th international conference on, pp. 1-4. ieee, 2012. [18] " dsr: the dynamic source routing protocol for multi-hop wireless ad hoc networks." [online ] . available : https ://www. ietf. org/rfc/rfc472 8 . txt. [accessed: 23 -mar-2016]. [19] forsmann, j. hope, robert e. hiromoto, and john svoboda. "a time-slotted on demand routing protocol for mobile ad hoc unmanned vehicle systems." in unmanned systems technology ix, vol. 6561, p. 65611p. international society for optics and photonics, 2007. [20] kuperman, greg, lenny veytser, bow nan cheng, scott moore, and aradhana narula-tam. "a comparison of olsr and ospf-mdr for large-scale airborne mobile ad-hoc networks." in proceedings of the third acm workshop on airborne http://www/ shahzad hameed (et al.), nature inspired optimization techniques, a review for fanets (pp. 40 58) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 57 networks and communications, pp. 17 22. acm, 2014. [21] billington, jonathan, and cong yuan. "on modelling and analysing the dynamic manet on-demand (dymo) routing protocol." in transactions on petri nets and other models of concurrency iii, pp. 98-126. springer, berlin, heidelberg, 2009. [22] haas, zygmunt j., marc r. pearlman, and prince samar. "the zone routing protocol (zrp) for ad hoc networks." (2002). [23] wei, yi, m. brian blake, and gregory r. madey. "an operation-time simulation framework for uav swarm configuration and mission planning." procedia computer science 18 (2013): 1949-1958. [24] park, vincent. "temporally-ordered routing algorithm (tora) version 1 functional specification." internet draft, draft-ietf-manet-tora-spec-04. txt (2001). [25] flury, roland, and roger wattenhofer. "randomized 3d geographic routing." in infocom 2008. the 27th conference on computer communications. ieee, pp. 834-842. ieee, 2008. [26] liu, cong, and jie wu. "efficient geometric routing in three dimensional ad hoc networks." in infocom, pp. 2751-2755. 2009. [27] karp, brad, and hsiang-tsung kung. "gpsr: greedy perimeter stateless routing for wireless networks." in proceedings of the 6th annual international conference on mobile computing and networking, pp. 243-254. acm, 2000. [28] ko, young‐bae, and nitin h. vaidya. "location‐aided routing (lar) in mobile ad hoc networks." wireless networks 6, no. 4 (2000): 307-321. [29] lidowski, robert l., barry e. mullins, and rusty o. baldwin. "a novel communications protocol using geographic routing for swarming uavs performing a search mission." in pervasive computing and communications, 2009. percom 2009. ieee international conference on, pp. 1 7. ieee, 2009. [30] pei, guangyu, mario gerla, and xiaoyan hong. "lanmar: landmark routing for large scale wireless ad hoc networks with group mobility." in proceedings of the 1st acm international symposium on mobile ad hoc networking & computing, pp. 11-18. ieee press, 2000. [31] basagni, stefano, imrich chlamtac, violet r. syrotiuk, and barry a. woodward. "a distance routing effect algorithm for mobility (dream)." in proceedings of the 4th annual acm/ieee international conference on mobile computing and networking, pp. 76-84. acm, 1998. [32] oh, hyondong, dario turchi, seungkeun kim, antonios tsourdos, lorenzo pollini, and brian white. "coordinated standoff tracking using path shaping for multiple uavs." ieee transactions on aerospace and electronic systems 50, no. 1 (2014): 348 363. [33] wan, jiuqing, liping zhong, and fan zhang. "cooperative localization of multi-uavs via dynamic nonparametric belief propagation under gps signal loss condition." international journal of distributed sensor networks 10, no. 2 (2014): 562380. [34] vincent, patrick, and izhak rubin. "a framework and analysis for cooperative search using uav swarms." in proceedings of the 2004 acm symposium on applied computing, pp. 79-86. acm, 2004. [35] kim, do-yup, and jang-won lee. "topology construction for flying ad hoc networks (fanets)." in information and communication technology convergence (ictc), 2017 international conference on, pp. 153-157. ieee, 2017. [36] leonov, alexey v. "application of bee colony algorithm for fanet routing." in micro/nanotechnologies and electron devices (edm), 2016 17th international shahzad hameed (et al.), nature inspired optimization techniques, a review for fanets (pp. 40 58) sjet | issn: 2616-7069 | vol. 3 | no. 2 | © 2020 sukkur iba university 58 conference of young specialists on, pp. 124-132. ieee, 2016. [37] leonov, alexey v. "modeling of bio inspired algorithms anthocnet and beeadhoc for flying ad hoc networks (fanets)." in actual problems of electronics instrument engineering (apeie), 2016 13th international scientific-technical conference on, vol. 2, pp. 90-99. ieee, 2016. [38] hu, lei, fei hu, and sunil kumar. "moth-and ant-inspired routing in hierarchical airborne networks with multi-beam antennas." ieee transactions on mobile computing (2018). [39] sharma, vishal, d. g. reina, and rajesh kumar. "hmadso: a novel hill myna and desert sparrow optimization algorithm for cooperative rendezvous and task allocation in fanets." soft computing (2017): 1-24. format template vol. 3, no. 1 | january june 2020 sjet | issn: 2616-7069 | vol. 3 | no. 1 | © 2020 sukkur iba university 23 illicium verum as a green source for the synthesis of silver nanoparticles and investigation of antidiatom activity against paeodactylum tricornutum muhammad nazim lakhan 1, rongrong chen 1, altaf hussain shar 1, kishore chand 1, muhammad basit chandio2 , ahmer hussain shah3, mukhtiar ahmed 1, rizwan ahmed4 , jun wang 1 abstract: biological fouling has caused a lot of concern in marine industries due to the attachment of microorganisms including bacteria, algae, and diatoms on a marine surface to create a biofilm. biofouling causes negative impacts on the marine industry such as an increase in weights of hulls, low speed, and high fuel consumption. in the recent past, nanoparticles have attracted a lot of attention in the fields of material science, chemistry, and biology owing to their rare biological properties. silver nanoparticles (agnps) have been long known for its strong toxicity against a wide range of microorganisms. herein, we synthesized the agnps via a green synthesis approach known for its benefits such as one-pot, inexpensive, and eco-friendly; by using illicium verum (iv) extract as a demoting and sustaining agent. further, characterization tests of obtained agnpsiv were investigated including ultraviolet-visible spectroscopy (uv-vis), fourier-transform infrared spectroscopy (ftir), x-ray diffraction (xrd), scanning electron microscopy (sem), transmission electron microscopy (tem) and atomic force microscopy (afm). the uv-vis result confirmed the agnps-iv formation with its surface plasmon resonance peak. ftir was tested to investigate the bio-functional groups liable for the agnps-iv synthesis. xrd peaks also meet with the standard of agnps (jcpds: 41-1402). sem, tem, and afm analysis of agnpsiv showed the hexagonal structure with 14.56 nm mean size. the cell growth of diatom on 5th day with blank sample suspension was 2.308 (cell 105 number/ml), while for agnps-iv sample suspension was 0.19 (cell 105 number/ml). the green synthesized agnps-iv showed excellent antidiatom activity against paeodactylum tricornutum (p. tricornutum) marine diatom. keywords: nanotechnology; silver nanoparticles; illicium verum; synthesis; characterization. 1key laboratory of superlight material and surface technology, ministry of education, harbin engineering university, people’s republic of china 2college of mechanical and electrical engineering, harbin engineering university, people’s republic of china 3department of textile engineering, balochistan university of information technology, engineering and management sciences, quetta, pakistan 4school of chemical engineering, dalian university of technology, people’s republic of china corresponding author; nazimlakhan@gmail.com lakhan m.n (et al.), illicium verum as a green source for synthesis of silver nanoparticles and investigation of their antidiatom activity against paeodactylum tricornutum diatom (pp. 23 -30) sjet | issn: 2616-7069 | vol. 3 | no. 1 | © 2020 sukkur iba university 24 1. introduction biological fouling is the accumulation of algae, plants, and microorganisms on marine surfaces immersed in seawater. antifouling is the ability of specifically designed materials to prevent biofouling by various numbers of microorganisms such as algae, fungi, and diatoms. development of eco-friendly and facile green synthesis of metallic nanoparticles (having size < 100 nm) has attained huge attention in recent days due to their ample areas of biological applications including antibacterial, diagnostics, and drug delivery systems [13]. metallic nanoparticles possess chemical and physical properties including a surface area to volume ratio and exhibit strong antibacterial property [4-5]. among the others, silver has received extreme importance due to its strong toxicity against microorganisms. currently, silver nanoparticles (agnps) are considered as rich particles with their applications in various areas including antimicrobial and antioxidant properties [6-8]. there are several approaches to agnps synthesis such as thermal decomposition, microwave irradiation, electrochemical, and biological. among them, the biological method has many benefits such as simple, less cost, and eco-friendly for large scale applications that do not use toxic chemicals, high temperature, and pressure [9]. interestingly, agnps can be synthesized by using enzymes, proteins, microorganisms, and plant materials. plant extract synthesis is considered as an efficient approach than chemical and microbial synthesis because plant works as demoting and sustaining agent in the preparation of agnps and the particles formed are more stable with different shapes and sizes. herein, we have used northeast vietnam and southwest china evergreen tree plant fruit illicium verum, also known as “chinese star anise” as a demoting and sustaining agent. star anise has been used in china for flavoring and medicine purposes for over three thousand years. it has been widely used in the medicines system and contains the principal constituent anethole which possesses antiviral, antibacterial, antifungal, and antioxidant activity. in this study, the agnps-iv synthesized via a green approach using an extract of iv as a demoting and sustaining agent. the asprepared agnps-iv were characterized by different techniques such as uv-vis, ftir, xrd, sem-edx, tem, and afm. furthermore, this is the first report of agnps-iv and its antidiatom activity against marine diatom p. tricornutum in the marine environment. fig. 1. (a) blank and (b) p. tricornutum diatom growth solution 2. materials and method 2.1. materials the fresh plant illicium verum (iv) fruit was obtained from the local market of harbin, china, and grinded in powder form. the silver nitrate (agno3) and ethanol (c2h6o) were received from tianjing chemical co., china. distilled water was used to wash the equipment and later dried in the oven. materials used in the synthesis process were of analytical grade. 2.2. preparation of plant extract 0.5 g of iv powder was weighted and dissolved with 400 ml of milli-q water and then the solution was boiled at 60°c for 20 min to obtain its aqueous extract. after cooling at room temperature the iv extract was filtered via whatman no.1 and stored in the refrigerator at 4°c for further experimental study. 2.3. biosynthesis of agnps-iv with illicium verum extract for the green synthesis of agnps-iv, the solution of 1 molarity was obtained by dissolving weighed amount of agno3 in 400 ml of distilled (di) water under lakhan m.n (et al.), illicium verum as a green source for synthesis of silver nanoparticles and investigation of their antidiatom activity against paeodactylum tricornutum diatom (pp. 23 -30) sjet | issn: 2616-7069 | vol. 3 | no. 1 | © 2020 sukkur iba university 25 sonication. then the as-prepared 80 ml of extract iv was added in agno3 aqueous solution drop by drop for reduction of ag+ into ag0 under the continuous magnetic stirring. the mixed solution was placed in a dark environment for 24 hrs to minimize the photoactivation of agno3. after the successful synthesis of the agnps-iv solution, agnps-iv was centrifuged and washed two times for 15 min at 8000 rpm with di water. later, the as-obtained agnps-iv was placed in a vacuum oven overnight at 60°c and collected for further characterization and antidiatom activity. 2.4. characterization the absorption spectrum of the synthesized agnps-iv was investigated by uv-vis spectrophotometer tu-1901 dual-beam in the range of 200-800 nm. ftir analysis was carried out using a perkin elmer spectrum 100 ftir spectrometer in the wave number range of 4000-500 cm-1 to identify the chemical constituents liable for the successful preparation of agnps-iv. xrd pattern was examined to check the nature of the as-obtained samples by using rigaku ttr at 40 kv and 150 ma within 2θ area between 10-90° with intensity cuka radiation (λ=0.15406 nm). the morphology of as-obtained agnps-iv was viewed by the sem instrument (joel, jsm-6480a) operated at a 20kv of the driving voltage. element and composition analysis of the powdered agnps-iv was conducted using a jeol’s edx detector attached to the sem machine. the size of as-obtained agnps-iv was observed by tem using an fei techni g2 instrument. the topography of agnps-iv was investigated by afm using a keysight equipment model 5500. the average mean size of nanoparticles was measured by nano measurer software. 2.5. antidiatom analysis the algae p. tricornutum were examined for the anti-diatom test to check the antifouling performance of agnps-iv. the algal stock solution of p. tricornutum was received from xiamen university ccma and it was growth in f/2 medium with a 12/12 light, dark cycle of fluorescent illumination at 2000 lux and growth sample solutions were shaken daily twice a day. blank sample and green synthesized agnps-iv (5ml) solution was poured in the algal solution at the bottom of the aquarium with at least 1×105 algal cells per ml and blank substrate was placed in both beakers to confirm the morphology of surface after 5 days’ immersion, later the beakers were placed in an incubator [10]. the diatom settling assay of blank and agnps-iv samples was recorded on an optical microscope. fig. 2. schematic route of agnps formation using plant extract of illicium verum (iv). 3. results and discussion the successful synthesis of agnps-iv was observed on uv-vis spectrum through the color formation. the color of the agno3/illicium verum extract mixture turned from light to dark brown indicates the successful formation of agnps-iv. the dark brown color appeared due to the excitation of surface plasmon resonance (spr) effect. further, the formation of the agnps-iv was observed by the spr absorption band at 425 nm in the uv–vis region as depicted in fig. 3 [11]. further, agnps-iv were characterized by ftir spectra to analyze the functional groups liable for demoting and sustaining of ag nanoparticles as depicted in fig. 4. the ftir spectrum shows different main peaks at 581, 1118, 1634, 2357, and 3459 cm-1. the peak appeared in the spectrum at 1634 cm-1 clearly shows the stretching vibration of c=o and indicating the formation of lakhan m.n (et al.), illicium verum as a green source for synthesis of silver nanoparticles and investigation of their antidiatom activity against paeodactylum tricornutum diatom (pp. 23 -30) sjet | issn: 2616-7069 | vol. 3 | no. 1 | © 2020 sukkur iba university 26 agnps-iv and capped with the biofunctional groups [12]. the peak at 2357 cm-1 and 1157 cm-1 represents the o-h and c-o stretching. the peak at 581 cm-1 indicates the existence of alkaloids. the peak at 3459 cm-1 was assigned to nh stretching vibration of amide group and aromatic rings [13]. fig. 3. uv-vis spectrum of agnps-iv. fig. 4. ftir spectrum of agnps-iv. the xrd pattern of agnps-iv is displayed in fig. 5. several different diffraction peaks were observed at 2θ of approximately 35.89°, 37.04°, 51.68°, 55.07°, 59.13°, 67.52° and 76.08° corresponding to reflections from the (004), (101), (104), (006), (105), (112) and (008) crystallographic planes of agnps-iv, respectively, and confirming the hexagonal structure of silver (jcpds, no. 41-1402) [14,15]. fig. 5. xrd pattern of agnps-iv. the morphology of the as-obtained agnpsiv was observed by sem as shown in fig. 6(a). it was seen that the larger particles are also formed with smaller particles which indicates the aggregation in ag particles and the evaporation of solvent while sampling preparation [16]. the edx spectrum of agnps-iv showed strong signal at 3 kev [17]. in fig. 6(b), the peak for cl was observed due to the presence of plant extract, while the peak of cu was due to the carbon grid that was used during sample preparation. the morphology and size of the agnps-iv were examined by tem and afm. the obtained tem result illustrated that silver nanoparticles are readily oxidized due to the functional compounds present in the plant extract and successfully formed with hexagonal in shape as depicted in fig. 7(a) [18-19]. in fig. 7(b), the measured average mean size of nanoparticles was 14.56 nm obtained through nano measurer software using the tem image. the dark shades on the surface of nanoparticles revealed the presence of plant extract. the afm image in fig. 7(c) showed that the particles are formed with little aggregation and marked lines showing the line size of particles at different positions. the particle size curve was obtained through nanoscope analysis software as shown in fig. 7(d). the afm analysis has similarities with the tem and sem results. lakhan m.n (et al.), illicium verum as a green source for synthesis of silver nanoparticles and investigation of their antidiatom activity against paeodactylum tricornutum diatom (pp. 23 -30) sjet | issn: 2616-7069 | vol. 3 | no. 1 | © 2020 sukkur iba university 27 fig 6. scanning electron microscopy image of agnps-iv (a), edx spectrum of agnps-iv (b). fig. 7. transmission electron microscopy image at 200 nm (a), particle size distribution through tem image (b), atomic force microscopy image (c), and particle size obtained through afm image (d) of agnps-i 1 diatoms are microscopic algae that grow on manmade surfaces present in the seawater. biofouling develops due to the attachment of diatoms, bacteria, and other microorganisms on the surfaces in seawater. the anti-settling test of diatom was analyzed to check the antifouling performance of the blank sample and agnps-iv. therefore, herein, the p. tricornutum diatom was tested to check the biofouling attachemnt. the inhibition growth effect of agnps-iv was observed in the p. tricornutum suspension [10]. from the anti-settling analysis, it was seen that lakhan m.n (et al.), illicium verum as a green source for synthesis of silver nanoparticles and investigation of their antidiatom activity against paeodactylum tricornutum diatom (pp. 23 -30) sjet | issn: 2616-7069 | vol. 3 | no. 1 | © 2020 sukkur iba university 28 the more algae cells were found on a blank sample, while agnps iv surface was attached with the no algae cells after 5 days’ immersion as shown in fig. 8(a-d). the diatom attachment was checked in suspension sample by an optical microscope attached with the cell count chamber haemocytometer. fig. 9 showed the cell number of diatoms in the p. tricornutum suspension on day 1 and after cultivation for 5 days. the absorbance of diatoms was less for agnps-iv sample, which was observed on uv-vis spectroscopy at 600 nm in algae solution, while for blank samples; its absorbance was almost the same after five days’ period. fig. 8. antidiatom activity of blank sample on (a) day 1, (c) day 5, and agnps-iv 5ml sample on (b) day 1 and (d) day 5. fig. 9. the cell number of diatoms (p. tricornutum) in the solutions with blank and agnps-iv samples. each point is the average of three readings lakhan m.n (et al.), illicium verum as a green source for synthesis of silver nanoparticles and investigation of their antidiatom activity against paeodactylum tricornutum diatom (pp. 23 -30) sjet | issn: 2616-7069 | vol. 3 | no. 1 | © 2020 sukkur iba university 29 4. conclusion in this article, we presented a green route for the synthesis of the silver nanoparticles from illicium verum extract. the amount of plant extract plays a vital role in the preparation of well-dispersed and small size nanoparticles and also acts as a reducing and stabilizing agent. the method employed here is one-pot, simple, inexpensive, and eco-friendly. the results confirm the uniform formation of small size nanoparticles with a hexagonal shape. the green synthesized agnps-iv showed excellent antidiatom activity against paeodactylum tricornutum diatom. in this regard, we can affirm that the agnps prepared by the green approach could be a potential tool in the near future to combat biofouling on manmade surfaces in seawater. acknowledgment the author’s greatly appreciated the financial support by the fundamental research funds of the central university (3072019cf1008), national natural science foundation of china (nsfc 51603053), the application technology research and development projects of harbin (2015raqxj038) and defense industrial technology development program (jcky2018604c011). references [1]. e. pavitra, , b. dariya, g. srivani, s.m kang, a. alam, p.r sudhir, m. a kamald, g. s.r raju, y.k han, b. v k. s lakkakula, g. p nagarajui, y. s. huh, engineered nanoparticles for imaging and drug delivery in colorectal cancer, seminars in cancer biology, 2019, pp. 1-14. [2]. s. ahmed, m. ahmad, b. l. swami, s. ikram, a review on plants extract mediated synthesis of silver nanoparticles for antimicrobial applications: a green expertis, j adv res, vol. 7, 2016, pp. 17-28. [3]. h. chandra, p. kumari, e. bontempi, s. yadav, medicinal plants: treasure trove for green synthesis of metallic nanoparticles and their biomedical applications, biocatalysis and agricultural biotechnology, 2020, pp. 147. [4]. r. dadi, r. azouani, m. traore, c. mielcarek, a. kanaev, antibacterial activity of zno and cuo nanoparticles against gram positive and gram negative strains, material science & engineering c, vol. 104, 2019, pp. 1-9. [5]. s. kheiri, x. liu, m. thompson, nanoparticles at biointerfaces: antibacterial activity and nanotoxicology, colloids and surfaces b: biointerfaces, 2019, pp. 1-43. [6]. a. chatterjee, s. khatua, k. acharya , j. sarkar, a green approach for the synthesis of antimicrobial biosurfactant silver nanoparticles by using a fern, digest journal of nanomaterials and biostructures, vol. 14, 2019, pp. 479-490. [7]. m. c. biswas, b. j. tiimob, w. abdela, s. jeelani, v. k. rangari, nano silica-carbonsilver ternary hybrid induced antimicrobial composite films for food packaging application, food packgaing and shelf life, vol. 19, 2019, pp. 104-113. [8]. p. senthilkumar, g. yaswant, s. kavitha, e. chandramohan, g. kowsalya, r. vijay, b. sudhagar, d. s. r. s. kumar, preparation and characterization of hybrid chitosansilver nanoparticles (chi-ag nps); a potential antibacterial agent, international journal of biological macromolecules, vol. 141, 2019, pp. 290-297. [9]. r. g. saratale, i. karuppusamy, g. d. saratale, a. pugazhendhi, g. kumar, y park, g. s. ghodake, r. n. bharagava, j. r. banu, h. s. shin, a comprehensive review on green nanomaterials using biological systems: recent perception and their future applications, colloids and surfaces b: biointerfaces, vol. 170, 2018, pp. 20-35. [10].r. chen, y. li, m. yan, x. sun, h. han, j. li, j. wang, l. liu, k. takahashi, synthesis of hybrid zinc/silyl acrylate copolymers and their surface properties in the microfouling stage, rsc advances, vol. 6, 2016, pp. 13858-13866. [11].p. das, k. ghosal, n. k. jana, a. mukherjee, p. basak, green synthesis and characterization of silver nanoparticles using belladonna mother tincture and its efficacy as a potential antibacterial and antiinflammatory agent, materials chemistry and physics, vol. 228, 2019, pp. 310-317. [12].b. kumar, k. smita, l. cumbal , a. debut, green synthesis of silver nanoparticles using andean blackberry fruit extract, saudi j biol sci, vol. 24, 2017, pp. 45-50. [13].r. mythili, t. selvankumar, s. kamalakannan, c. sudhakar, f. ameen, a. alsabri, k. selvam, m. govarthanan, h. kim, utilization of market vegetable waste for silver nanoparticle synthesis and its antibacterial activity, materials letters, vol. 225, 2018, pp. 101-104. lakhan m.n (et al.), illicium verum as a green source for synthesis of silver nanoparticles and investigation of their antidiatom activity against paeodactylum tricornutum diatom (pp. 23 -30) sjet | issn: 2616-7069 | vol. 3 | no. 1 | © 2020 sukkur iba university 30 [14].k. rajathi and a. rajendran, antimicrobial activity of silver nanoparticles from substituted and unsubstituted imidazolium ionic liquids, international journal of pharmaceutical sciences research, vol. 8, 2017, pp. 4335-4340. [15].f. a. sheikha, m. a. kanjwal, h. kim, d. r. pandeya, s. t. hong, h. y. kim, fabrication of titanium oxide nanofibers containing silver nanoparticles, journal of ceramic processing research, vol. 11, 2010, pp. 685-691. [16].a. h. shar, m. n. lakhan, j.wang, m.ahmed, k.t. alali, r. ahmed, i. ali, a. q. dayo, facile synthesis and characterization of selenium nanoparticles by the hydrothermal approach, digest journal of nanomaterials and biostructures, vol. 14, 2019, pp. 867-872. [17].b. mahitha, b. d. p. raju, g. r. dillip, c. m. reddy, k. mallikarjuna, l. manoj, s. priyanka, k. j. raon, j. sushma, biosynthesis, characterization and antimicrobial studies of agnps extract from bacopa monniera whole plant, digest journal of nanomaterials and biostructures, vol. 6, 2011, pp. 135142. [18].s. zoha, m. ahmad, s. j. a. zaidi, m. n. ashiq, w. ahmad, t. j. park, m. a. basit, zno-based mutable ag2s/ag2o multilayered architectures for organic dye degradation and inhibition of e. coli and b. subtilis, journal of photochemistry & photobiology, a: chemistry, 2020, pp. 1-27. [19].k. chand, m. i. abro, u. aftab, a. h. shah, m. n. lakhan, d. cao, g. mehdi, a. m. ali mohamed, green synthesis characterization and antimicrobial activity against staphylococcus aureus of silver nanoparticles using extracts of neem, onion and tomato, rsc advances, vol. 9, 2019, pp. 17002-17015. format template vol. 1, no. 1 | january june 2018 sjet | issn: 2616-7069 | vol. 1 | no. 1 | © 2018 sukkur iba 1 automatic positioned controller parabolic solar dish prototype asif a.rahimoon1, izhar a.sohu1, m.ishaque junejo1, ali abbas ,s.nawaz shah1 ,arslan ahmed sohu2 abstract: this paper discusses the development of dual axis parabolic dish tracker application for automatized position power system. this prototype tackles solar light in solar sterling design system or concentrated photovoltaic design by implementation of digitalize control circuit to enhance concentrating solar power and concentrating photovoltaic applications. a normally 121.92cm dish is designed with h-bridge controller technique & slew drive actuator mode to capture solar irradiances. the surface of dish is polished with 12 aluminum bars to concentrate the solar irradiance in one reflective axis. economic justification for pakistan’s industries would be possible if these automated based renewable prototypes are promoted in market in compare of single pv panel. this prototype controls the all weather conditions, utilizing real time flexible timing control strategy and photoelectric tracking scheme to provide cost effective product for industrial power generation applications. this locally adaptive material based prototype encouraged the result about 33% efficient with compared to photovoltaic panel. keywords: pakistan energy future; solar concentrator; thermal energy utilization. 1. introduction the world-wide rate of countries are utilizing decentralized power system to maintain the energy demand with small power energy system. these mini energy systems can be fabricated with renewable sources such as solar cooker, solar geyser, solar hydrogen productive devices and parabolic solar dish collectors [1, 2]. utilization of parabolic reflector is proven to be effective through observation of different researchers that worked on heat collector by designing parabolic solar dish [3, 4]. the solar heat collectors are more reliable in operation when the suitable tracking scheme is installed with it. the different heat collectors are used from 1 faculty of engineering, science & technology (fest), indus university karachi, pakistan 2department of electrical engineering,sukkur iba university,sukkur,pakisan corresponding email: asif.ahmed@indus.edu.pk ancient times in bucolic sites as in 212 bc, archimedes used sun light to burn roman fleet and in 10th century ibn sahl worked on parabolic mirror. the same trend is followed by new researchers on parabolic solar dish to capture heat and dispatch an economical and optimized prototype in market with different applications [5, 6, 7]. in proposed prototype the solar dish is fabricated with aluminum glass that is integrated with controller scheme of tracking with concerned measurement of azimuth angle to gain efficient sun-light. as by researcher there are different scenarios of designing this prototype on small level application to commercial based with alteration of its tracking control techniques such as plc, scada & microcontroller to mailto:asif.ahmed@indus.edu.pk asif a. rahimoon (et al.), automatic positioned controller parabolic solar dish prototype (pp. 1 6) sukkur iba journal of emerging technologies sjet | volume 1 no. 1 january – june 2018 © sukkur iba university 2 make parabolic heat collector efficient [8, 9, 10].the integrated technology of this proposed system that is comprised of arduino based dual axis tracker, 12v operating power window motors and sensor fault control strategy to maintain elevation and tilt angles smoothly enhance the future work of power industries. 2. proposed dish prototype for pakistan, in rural or desert areas where sunlight appears invariably under seasonal mode, the desired system is proposed to capture the solar irradiance in regular and seasonal mode. with high reflective glass material the heat collection is merged under a single focal point of parabolic dish [11, 12]. the maintenance of solar dish elevation angle and tilt angle is done through ldr actuators and power window motors. the whole tracking of proposed parabolic solar dish is based on arduino based chip board that regulate the whole system in optimal and efficient mode. the power running actuators get their startup power service from an external battery to improve the remedies of sensor mechanism. the designed automated dual axis tracking prototype is capable to attained high temperature applications like as hot water & steam generation. as in previous research of dual axis the system rotates with their both operative modes which make the tracker slower in perception of heat measurement and sensor functioning so, to improve this state of sensor the optional mode is included in designed parabolic dish prototype that is tested at indus university karachi with latitude 23.9207°n and longitude 67.0882°e which gives you option to run your dish on single axis or both axis as suitable with your application area. fig. 1. designed prototype. 3. hardware development the system is integrated with different parts to achieve the efficient output that is also calculated with some algorithms. the adoptive algorithm are included as parabola calculator2.0 for designing parameters of solar dish, solar angle meter for angle calculation of x-axis & y-axis geometry, arduino assembly for programming of controller chip, generalized equation are adopted with used of solar geometry tools that are as sun calculator & sun earth tool for solar positioning and shadow effect rate.the arrangement of these integrated tools are shown in figure 3. fig. 2. block diagram. 3.1. parabolic solar dish design asif a. rahimoon (et al.), automatic positioned controller parabolic solar dish prototype (pp. 1 6) sukkur iba journal of emerging technologies sjet | volume 1 no. 1 january – june 2018 © sukkur iba university 3 table i. detailed sheet of dish. table ii. automatic tracking parameters. 3.2. sensor configuration there are a lot of sensors used to run the trackers with opto-electronics technology. here in this designed prototype we have installed ldr wall that will function with 12v output power. the designed wall is configured with h-bridge drive module and power motor rotation. as by research mostly implemented motor are servo motor and dc gear motors, but due to misalignment and speed management challenges this prototype is designed with 12v dc gear with slew controller technique and 12v wiper motor. slew controller technique is installed to tilt the dish with optimum speed rate according with input rated pulse of pwm generator. each motor gets its input from h-bridge dual axis module which had internal 5v avr and 2 pulse generators. 3.3. arduino controller arduino is an open source digital it that assemble the software and hardware designed projects with less complexity. the omega controller arduino is computationally installed with this prototype which is easy to program with in running project as compared of other technologies. as this prototype needs simple management to provide an optimum output result so the easy configurable controller is used to track and run the parabolic solar tracker. 3.4. equations a) hour angle 𝑯. 𝑨 = 𝒏𝒐. 𝒐𝒇 𝒎𝒊𝒏𝒖𝒕𝒆𝒔 𝒑𝒂𝒔𝒕 𝒎𝒊𝒅𝒏𝒊𝒈𝒉𝒕 𝟒° 𝒎𝒊𝒏 b) change in hour angle:= 𝒔𝒊𝒏∞−𝒔𝒊𝒏𝜹.𝒔𝒊𝒏∅ 𝒄𝒐𝒔𝜹.𝒄𝒐𝒔∅ c) declination angle d.a= 𝒔𝒊𝒏−𝟏∗ [𝒔𝒊𝒏(𝑬𝒂𝒓𝒕𝒉 𝑻𝒊𝒍𝒕 𝒂𝒏𝒈𝒍𝒆) ∗ 𝒔𝒊𝒏(𝒆𝒂𝒓𝒕𝒉 𝒆𝒍𝒊𝒑𝒕𝒊𝒄𝒂𝒍 𝒑𝒐𝒔𝒊𝒕𝒊𝒐𝒏)] d) altitude angle = 𝒔𝒊𝒏 ∝= 𝒔𝒊𝒏𝜹 ∗ 𝒔𝒊𝒏∅ + 𝒄𝒐𝒔𝜹 ∗ 𝒄𝒐𝒔𝒘 ∗ 𝒄𝒐𝒔∅ e) 𝑨𝒛𝒊𝒎𝒖𝒕𝒉 𝒂𝒏𝒈𝒍𝒆. 𝒔𝒊𝒏𝜶 = 𝒔𝒊𝒏𝒘. 𝒄𝒐𝒔𝜹 𝒄𝒐𝒔𝜶 f) shadow length= |op|=h/tanα 4. parabolic dish working as concerned with dual axis solar heat collector from previous research work, different challenges were occur that are in sense of cosine effect, dish alignment, sensor actuation and mppt technique(choice of controller). so, an automatic motorized control prototype is presented with 121.92cm diameter dish to enhance the solar irradiance application. the working is performed at karachi, sindh pakistan with coordinate location of latitude 23.9207°n and longitude 67.0882°e .the whole implementation of solar designed dish with its all configured asif a. rahimoon (et al.), automatic positioned controller parabolic solar dish prototype (pp. 1 6) sukkur iba journal of emerging technologies sjet | volume 1 no. 1 january – june 2018 © sukkur iba university 4 controller is accomplished on 4*4ft rectangular frame. the system perform its working when it get the input pulse from preset topology of controller to derive the motor in suitable direction either to tilt the dish or curve the dish with the help of dc-gear and power wiper motors. the output is performed with placement of 20w solar panel on parabolic dish. table iii. result analysis. change in hour angle angles measured time hour static solar pv prototype result shadow length(ft) altitude azimuth voc isc power voc isc power 𝟏𝟐. 𝟒𝟗𝟎 23.550 130.190 9am 19.7 0.15 2.95 20.3 0.29 5.88 7.51 𝟐𝟓. 𝟎𝟗𝟎 32.90 141.910 10am 20.5 0.36 7.63 20.3 0.33 5.69 5.05 𝟑𝟒. 𝟐𝟗𝟎 39.80 157.020 11am 20.1 0.16 3.22 19.2 0.36 6.91 3.93 𝟑𝟖. 𝟔𝟕𝟎 43.150 175.180 12pm 20.1 0.34 8.33 19 0.69 13.11 3.51 𝟑𝟕. 𝟏𝟓𝟎 42.040 194.120 1pm 20.4 0.42 8.57 19 0.94 17.86 3.64 𝟑𝟎. 𝟏𝟗𝟎 36.800 210.90 2pm 20.2 0.43 8.68 20 0.67 13.4 4.39 𝟏𝟗. 𝟏𝟎 28.50 224.20 3pm 20 0.36 7.2 20.5 0.51 10.45 6.03 d at e tim e hou r angl e chang e in h.a yearly average solar irradianc e rate angles shadow length(ft ) prototype ldr output volts altitud e angle azimuth angle y-axis x-axis ldr 1 ldr 2 ldr 3 ldr 4 28 .ja n sunri se 0.460 1941 9.am −450 12.490 23.730 130.100 7.51 0.72 3 0.56 7 3.63 1 3.78 3 10a m −300 25.090 33.150 141.800 5.05 0.73 3 0.81 6 3.9 3.78 11a m −150 34.290 40.070 157.020 3.93 3.21 1 2.29 7 3.91 0 3.69 6 12p m 00 38.670 43.340 175.270 3.51 4.88 8 4.94 1 4.95 4.99 1pm 150 37.150 42.190 194.280 3.64 3.83 0 3.91 0 4.98 5 4.99 0 2pm 300 30.190 36.920 211.110 4.39 3.45 4.05 4.97 6 4.98 5 3pm 450 19.10 28.580 224.40 6.03 3.93 3.84 6 4.94 1 4.89 2 asif a. rahimoon (et al.), automatic positioned controller parabolic solar dish prototype (pp. 1 6) sukkur iba journal of emerging technologies sjet | volume 1 no. 1 january – june 2018 © sukkur iba university 5 fig. 3. sun position graph. fig. 4. prototype parts. 5. conclusion the tariff of electric price is become inverse proportion to oil and fossil fuel tariff that creates that hazard effect of load shading. so to provide a sustainable tool with development of power optimized techniques, we have to promote renewable energy applications with help of technical expertise. in this research an innovative low cost parabolic dish is analyzed optically to compensate the mppt tracking issues. the thermally analyzed result is obtained with hour angle formulae tools and flux meter that is about 210𝑤/𝑚2 on parabolic dish at 21.8℃ temperature. this research concluded that the design and function of the prototype is proven to be efficient. parabolic dish with single axis sun tracking mechanism upturns the magnitude of current, voltage and power of mounted solar panel is about 23.6% in compare of the static solar penal and parabolic dish with dual axis sun tracking mechanism upturns the magnitude is about 33% in compare of the static solar penal. references [1] a. ahmed, p. hameed, z. a. memon, a. k. akhani, and p. lohana, “implementation of design for efficiency enhancement of solar photovoltaic panel through parabolic solar dish tracker,” 1st international conference on contemporary sociology, social sciences and sustainable development, march-2224, 2018. [2] a. shaikh, m. h. kabir, i. a. sohu , a. ahmed, a. ahmed sohu “implementation of design for solar tracking system using fpga” international conference on emerging trends in telecommunication & electronic engineering, (icet), feb-2728, 2018. [3] i. gopang, p. hameed, and z. a. memon, “parabolic dish solar system for increased power effeciency,” the first international conference on industrial engineering and management applications, (feb-2017). [4] k. das, h. ghosh, m. sengupta, “single axis solar tracking system using microcontroller (atmega328) and servo motor,” international journal of scientific and research publications, vol. 6, no. 6, june 2016. [5] h. hijazi ,o. mokhiamar, and o. elsamni, “mechanical design of a low cost parabolic solar dish concentrator,” alexandria engineering journal, vol. 55, pp. 1–11, 2016. [6] s. danial and m. boroushaki, “design analysis and optimization of solar dish,” int. journal of renewable energy. [7] m. navin, k. magar, a. abhishek, j. fernandes, p. kulkarni, “solar steam asif a. rahimoon (et al.), automatic positioned controller parabolic solar dish prototype (pp. 1 6) sukkur iba journal of emerging technologies sjet | volume 1 no. 1 january – june 2018 © sukkur iba university 6 power generator,” international conference on technologies for sustainable development (ictsd-2015), feb. 04 – 06, 2015. [8] safaskouri, salwabouadila, sassi ben nasrallah, “estimating intercept factor of a solar parabolic dish with photogrammetric equipment,” 6th international renewable energy congress (irec), 2015. [9] s. povlovic, v. stefanovic, d. vasiljevic, and e. petrovic, “optical design of solar parabolic concentrating collector based on trapezoidal reflective petals,” journal of energy and power engineering, april2015. [10] n. m. arago, t. m. amado, and j. w. f. orillo, “utilization of cassegrain feed parabolic antenna design in increasing the efficiency of photovoltaic module,” 7th ieee international conference humanoid, nanotechnology,information technology communication and control environment and management (hnicem), nov-2014. [11] b. anak sup, m. farid, t. zanariah, r. a. bakar, and g. ming, “effect of rim angle to the flux distribution diameter in solar parabolic dish collector,” 2nd int. conference on sustainable energy engineering and application, 2014. [12] m. a. soderstrand, s. b. lee, and p. chung, “mini-dish based hybrid concentrated solar power system for home use,” ieee 56th int. midwest symposium on circuit and system (mwscas), aug-2014. format template vol. 3, no. 1 | january june 2020 sjet | issn: 2616-7069 | vol. 3 | no. 1 | © 2020 sukkur iba university 31 mini hydel power generation from over head tanks using pelton turbine basit ali1, abdul attayyab khan1, kiran khalid1, m. israr1 ,madiha nazim1 abstract: the electricity demand is increasing day by day all over the world. a lot of efforts are made to make the buildings productive and self-sustainable. due to this fact it is proposed to get energy from overhead water tanks. following this approach, a 20 m high water tank is considered, water in the pipeline rotates a mini-hydro turbine. the purpose of this scheme is to generate power using low cost mini hydro turbine having negligible environmental effects. the experimental setup of this idea consists of a mini-hydro turbine having a diameter of 0.21 m which is coupled with a dc generator via a chain-gear mechanism to obtain desired rotation. the sensor box is designed to monitor the technical parameters. the calculations and theoretical concepts are presented using basic theory and equations of fluid mechanics and turbo-mechanics, outputs are validated using mathematical and experimental results. this system can replace the ordinary backup units for power generation as it will not consume the power of the existing system for charging batteries. keywords: pelton turbine, power generation, green energy, low head, hydropower. 1. introduction energy resources of the world are mainly divided into two categories fossil fuels resources and renewable resources. renewable resources have the advantage of providing free of cost energy without major environmental effect e.g. solar, wind, biomass, and hydro energy, etc. hydropower represents a great source of producing a handsome amount of energy as compared to fossil fuels [1]. 16.4% generation of the world’s power is generated from hydropower plants. among all the renewable resources the energy of water is more cost-effective. the report of the international journal on hydropower shows that 23% to 63% of countries extracting hydropower for 1 department of electrical engineering, bahria university karachi campus karachi, pakistan corresponding author: basitali_91@yahoo.com electricity generation [2], [3]. hydropower plants at a low scale and domestic scale are known as a major resource of renewable energy today. they have more capacity than other renewable resources. mini-hydel power plants are capable of generating a maximum power up to 5 kw. mini-hydel power plants are useful in remote areas where a small amount of electricity is required such as for small lightening bulbs, radio or television, etc. this system has low maintenance and installation cost. the mechanism of minihydel power plants is the same as dams, the overhead tank acts as a reservoir to store the water and a mini turbine is used to convert the energy of flowing water to rotational energy. the mini hydel power plant is a solution to extract hydropower from an overhead water basit ali (et al.), mini hydel power generation from overhead tanks using pelton turbine (pp. 31 36) sjet | issn: 2616-7069 | vol. 3 | no. 1 | © 2020 sukkur iba university 32 tank to ful fill the power demand at the domestic level. if such plants are installed on overhead tanks than these plants can generate a good amount of electricity along with that it lowers the burden on the distribution network to contribute to the economy of the country. a comparative study is for rural areas using small turbines discussed [4]. small projects for irrigation discussed in [5]. in previous studies, the specific overhead hydel source is not used for the domestic generation of electricity. a turbine is a form of machine that converts turning energy from a liquid that is selected through a system of the rotor into operating effort or energy. rapidly moving fluid (liquids or gases) strikes the turbine’s blades. when the water strikes the runner of the turbine energy of flowing water is transformed into mechanical rotational energy, along with that generator is coupled with the turbine. when the runner rotates the energy produced from the shaft rotation is collected by a generator that converts the rotating mechanical energy to electrical energy. the reaction machine generates the torque by low pressure and weight of water and the impulse machines require high velocity of jet and high pressure to generate the torque. due to this fact it required casing [6]. the selection of a suitable turbine is very important for setting up a new project. large scale electrical energy production mostly depends on the uses of turbines. for domestic production, small turbines can be installed which can perform work under low pressure of water. it also has very low maintenance as compared to other large units of the turbine. 2. methodology 2.1. hydro turbine the hydro turbine is a type of machine that transforms the kinetic energy of the fluid to moving energy. hydraulic turbine has a row of blades exactly fitted to the rotating shaft. when liquid, mostly water passes through the hydraulic turbine it hits the buckets and makes the shaft rotate. while flowing liquid (water) through the hydraulic turbine the pressure and velocity of the liquid (water) is reduced, the effect of this parameter results in the development of torque and rotation of the turbine give the perfect output. hydropower turbines are divided into two main categories; impulse and reaction turbine as in fig. 1. each turbine of these types is used for a certain range of values of head and flow rates of water. the reaction turbine is mostly used for those sites having low higher flow and head. a reaction turbine produces power by the combination of pressure and flow of water. in reaction turbine runner is placed directly in the water flowing over the blades rather than striking each individually. impulse turbines mostly used because of low flow and high head. the impulse turbine discharges to atmospheric pressure to rotate the runner with the use of the velocity of the water. flowing of water strikes every bucket on the runner. no section on the lower side of the turbine and the water flows out the bottom. reaction turbines are mostly used for those sites having higher flow and low head. a reaction turbine produces power by the combination of pressure and flow of water [7]. fig 1: types of hydro turbine 2.2. turbine selection the turbine is directly linked with generator pulleys, gears, and belts. speed of generator depends on the belt [8][3], the performance of the mini-hydro system basit ali (et al.), mini hydel power generation from overhead tanks using pelton turbine (pp. 31 36) sjet | issn: 2616-7069 | vol. 3 | no. 1 | © 2020 sukkur iba university 33 depends on water and the efficiency of turbine wheel pelton turbine is one of the most commonly used impulse turbines. pelton turbines are suitable in case of high heat. kinetic energy is only available at the inlet of the turbine. the main parts of the pelton turbine are nozzle, bucket and runner, casing, and breaking jet. the velocity of the water jet is doubled as compared to buckets and according to the obtained head of water. fig. 2 shows the structure of pelton turbine. fig 2: pelton turbine 2.3. generator selection synchronous and induction generators are being used in different types of generation plants and are available in a single and threephase system [8]. dc generator is used for the establishment of this prototype. dc generator converts mechanical energy into electrical energy. to convert a dc generator into a dc motor no change in construction is required and the same for the motor to the generator, for this reason, we can say that it is a dc machine. so, a self-excited dc generator is a good choice for this system. fig 3 shows the dc generator used in the experiment. fig 3: dc generator 2.4. chain gears the dc generator required 452 rpm to give maximum output. the rpm of the turbine was not much enough to reach the requirement of the dc generator. to increase the rpm the gear mechanism is introduced in the system. the chain gear system was introduced to a couple of generators with the turbine. the pulley with more number of teeth was coupled with the turbine shaft and pulley with less number of teeth was coupled with the generator shaft to more rpm at the generator shaft as shown in fig. 4. fig 4: chain gears 2.5. electronic circuit 2.5.1 charge controller: the charge controller is a circuit which is used for the battery charging purpose. the power generated from the generator is not constant it depends upon the flow of water and the rpm of the turbine. so, to charge the battery from this type of power we need a basit ali (et al.), mini hydel power generation from overhead tanks using pelton turbine (pp. 31 36) sjet | issn: 2616-7069 | vol. 3 | no. 1 | © 2020 sukkur iba university 34 charging circuit. fig. 5 shows the circuit diagram of the charge controller. fig 5: charge controller 2.5.2 inverter the system generated output was useful for only dc devices. the output of the dc generator was not useful for the ac devices. so, to make it useful for all devices an electronics circuit is involved. the inverter is an electronic circuit that converts the dc power into ac power. there are two options in the system both ac and dc now the output of the generator can be used for both types of devices. the inverter circuit involves a number of a transistor for the switching purpose. a step-up transformer is used in the circuit to increase the voltage from 12 v to 220 v which are useful for domestic usage. 2.6 sensors there are five sensors used in this prototype for measuring different parameters. rpm sensor is used to measure the rrotation of the turbine. it is designed with arduino and lcd is used for the display. flow sensor is used to measure the flow rate of the water. it installed just before the inlet of the turbine. a vibration sensor is used to measure the vibration of the system. it is installed at the turbine assembly. a bourdon tube type pressure gauge is used to monitor the pressure of the water. it installed just before the flow sensor. water level indicator is used to monitor the level of water. three leds are used to indicate the level of water. it is installed in the water storage tank. 3. working the energy of the flowing water through the pipeline is utilized to move the runner of the turbine. the pressure provided to the turbine is very small, due to this impulse turbine will be more suitable hence the pelton turbine is selected for this design. after entrance from the overhead of the tank into the inlet of the casing, the nozzle is attached to the casing to improve the velocity. high-pressure water than hits the cups followed by exit pipe connected through the tap. a display box depicted in fig. 6 is used to show the readings of the different parameters (i-e) (flow meter, rpm sensor, vibration sensor, and current sensor). fig 6: hardware setup the working of pelton turbine fig. 7 consists of four main parts that are nozzle, buckets and runner, casing, and the last one are breaking jet. the high speed of water flow through the penstock and water jet emerging in the nozzles hit the buckets of the runner. the generator is connected to the shaft of the runner that converts the moving energy into electrical energy and the arrangement of the nozzle is set to the close of penstock which basit ali (et al.), mini hydel power generation from overhead tanks using pelton turbine (pp. 31 36) sjet | issn: 2616-7069 | vol. 3 | no. 1 | © 2020 sukkur iba university 35 helps to accelerate water and flow of water with prohibitive speed and greater velocity and eject atmospheric pressure. when the water hits the buckets it divides the bucket into two half and then the turbine starts to rotate. the water jet velocity is double as compared with the velocity of the bucket. the buckets of the turbine are mounted on the circular path with equal spacing. due to this, the runner rotates at a very high speed. the energy of jet will decrease in the form of kinetic energy because the jet changes its direction due to the spherical shape of buckets and produce urotation and waterfall into the tailrace. fig 7: pelton turbine in the casing 4. results a pelton turbine was designed by using basic turbine formulae [9]. complete calculations of all the parameters are depicted in table i. there is the direct relation between the hydropower, flow of water (q), head (h), gravitational force (g) overall efficiency (no) where, h = 20 m p = q * h *g * 𝑛𝑜 (1) where overall efficiency is directly related to the mechanical efficiency (𝑛𝑚), hydraulic efficiency (𝑛h ), and volumetric efficiency (𝑛𝑣). 𝑛𝑜=𝑛h∗ 𝑛𝑚∗ 𝑛z (2) the number of buckets is the main part of the designing of the pelton wheel. the diameter of each bucket is 0.21 m, the total number of buckets is 24. each bucket mounted together with shaft and used to increase the ability of the turbine to move with good speed and give smooth rotation [10][11][12]. where c is the coefficient of velocity that varies from 0.97 to 0.99. n is the speed of the turbine in revolution/minute (rpm) which is 800. specific speed ratio (f) that varies between 0.43 and 0.48. the designed buckets of the pelton turbine are depicted in fig. 8. table 1 shows the complete parameter calculations of the system. table 1: system parameters s.no system parameter calculations 1 flow rate (q) 0.0022 m 3/s 2 velocity of water v1 19.50 m/s 3 velocity of cup (u) 8.77 m/s 4 diameter of turbine 0.21 m 5 diameter of jet (d) 0.012 m 6 jet ratio (m) 17.5 7 number of buckets (z) 24 8 length of buckets 2.76 cm 9 breadth of buckets 3.36 cm 10 depth of buckets 0.72 cm 11 hydraulic efficiency 0.98 12 volumetric efficiency 0.9 13 rotor power 0.3851 kw 14 mechanical efficiency 0.9 15 overall efficiency 0.8 16 power 0.348 kw 17 specific speed 11.158 basit ali (et al.), mini hydel power generation from overhead tanks using pelton turbine (pp. 31 36) sjet | issn: 2616-7069 | vol. 3 | no. 1 | © 2020 sukkur iba university 36 fig 8. buckets of pelton turbine 5. conclusion hydropower is the main natural and clean resource of renewable energy. the best thing about hydropower is that it is free of cost with minimal environmental effects. this prototype used mini hydel technology we can produce free of cost energy which can be stored in the battery. hydro-power is always being a main and important part of electricity generation. by this mini hydel generation domestic model, we can generate power up to 0.348 kw which can be increased by increasing the flow rate of water. the system can be enhanced and can be used in tall buildings and municipality overhead water tanks. a sensor box is attached which monitors different parameters of the whole system. references [1] adhau, s. p., r. m. moharil, and p. g. adhau. "mini-hydro power generation on existing irrigation projects: case study of indian sites." renewable and sustainable energy reviews 16.7 (2012): 4785-4795. [2] paish, oliver. "small hydro power: technology and current status." renewable and sustainable energy reviews 6.6 (2002): 537-556. [3] saket, r. k. "design, development and reliability evaluation of micro hydro power generation system based on municipal waste water." 2008 ieee canada electric power conference. ieee, 2008. [4] adhau, s. p. "a comparative study of micro hydro power schemes promoting self sustained rural areas." 2009 international conference on sustainable power generation and supply. ieee, 2009. [5] adhau, s. p., r. m. moharil, and p. g. adhau. "mini-hydro power generation on existing irrigation projects: case study of indian sites." renewable and sustainable energy reviews 16.7 (2012): 4785-4795. [6] mmsrs, bhargav, s. p. anbuudayasankar, and k. balaji. "power generation by high head water in a building using micro hydro turbine—a greener approach." environmental science and pollution research 23.10 (2016): 9381-9390. [7] nag, p. k. power plant engineering. tata mcgraw-hill education, 2002. [8] kothari, d. p., k. c. singal, and rakesh ranjan. renewable energy sources and emerging technologies. phi learning pvt. ltd., 2011. [9] yahya, ahmad khusairee, wan noraishah wan abdul munim, and zulkifli othman. "pico-hydro power generation using dual pelton turbines and single generator." 2014 ieee 8th international power engineering and optimization conference (peoco2014). ieee, 2014. [10] cobb, bryan r., and kendra v. sharp. "impulse (turgo and pelton) turbine performance characteristics and their impact on pico-hydro installations." renewable energy 50 (2013): 959-964. [11] ali, basit, et al. "portable solar powered dc pumping system using pump jack and mppt." 2019 2nd international conference on computing, mathematics and engineering technologies (icomet). ieee, 2019. [12] ali, basit, and imran siddique. "distribution system loss reduction by automatic transformer load balancing." 2017 international multi-topic conference (inmic). ieee, 2017. [13] ali, basit, a. a. khan, and imran siddique. "analysis of distribution system losses due to harmonics in iesco." 2018 ieee international conference on information and automation for sustainability (iciafs). ieee, 2018. format template vol. 1, no. 1 | january june 2018 sjet | issn: 2616-7069 | vol. 1 | no. 1 | © 2018 sukkur iba 45 fuzzy logic based speed controller for a container ship abdul qadir1, dur muhammad, mukhtiar unar2, jawaid doudpoto2, mahmood khatak2 abstract: speed control of marine ships is one of the leading problems in terms of safety and economy. this research aims at designing a fuzzy logic-based speed controller for a marine ship. the dynamic model of container ship is considered. fuzzy logic-based approach is employed to control the variations and to maintain the controller performance under the ideal conditions as well as during rough weather. matlab is used for simulation. the results show that the proposed controller has enhanced control performance compared to conventional controllers, efficiently confine the influence of the environmental disturbance, ensure perfectly control, and have good robustness. keywords: container ship, speed control, fuzzy logic, disturbances. 1. introduction it is essential for the marine ships to have some sort of speed controller to control and govern the speed of the ship to improve stability and maneuverability of ship during course keeping, course changing and pitching motion. because while the ship is under the sea conditions, in very short span of time the propeller load will change during the pitching motion of the ship as the propeller may be close to or above the surface of water. various researchers have contributed in this area. le luo et al. worked on electric propulsion system of ship [1]. his work is based on development of pid controller. y. luo et al. also worked on electrical propulsion system and tested pi control mode for combined power and speed control of marine ship [2]. rigatos et al. presented the fuzzy control for 1 mechanical engineering, faculty of engineering and management sciences isra university hyderabad 2 mechatronics engineering, institute of information and communication technologies muet jamshoro corresponding email: aq.channa@isra.edu.pk adaptive ship steering problems [3]. w meng et al. presented the fuzzy logic technique for dynamic positioning of ship [4]. tadeusz et al. worked on the effect of wind, waves and loading conditions on speed of ship [5]. the abovementioned research is based on the design of pid or pi controller for electric propulsion, speed and power control, however the speed control of ship under sea is a non-linear and time varying and pid controller is not effective in dynamic behavior, robustness and control. the mass of the container ship, hydrodynamic force and moments also require complex mathematical modelling, whereas the design of fuzzy logic controller is expert knowledge-based system and widely used by control researchers for ship steering control, dynamic positioning of ship and electric propulsion control. published studies have never considered fuzzy logicmailto:aq.channa@isra.edu.pk abdul qadir (et al.), fuzzy logic based speed controller for a container ship (pp. 45 50) sukkur iba journal of emerging technologies sjet | volume 1 no. 1 january – june 2018 © sukkur iba university 46 based speed control design for a marine ship. considering fuzzy logic in marine ships will be useful in regulating and advancing the speed control of marine ships. this study thus proposes a fuzzy logic-based speed controller which maintains the desired performance in both ideal conditions as well as in presence of disturbances. 2. dynamics of a ship a rigid body can be completely defined by six coordinates as shown in fig. 1 therefore, six degrees of freedom are necessary to describe the motion of a ship [6] as mentioned in table 1, where the x, y and z coordinates represent the linear motion along x, y and z, and the ,  and  represent the angular motion. table 1. notation of ship motion. 2.1. container model the mathematical model for a container ship has been presented by son and nomoto [8]. the parameters of the container model are given in table 2 [8]. table 2. container ship parameters. state vector of a container ship can be defined as x = [ u v r x y  p  δ n]' (1) the definitions of all elements of state vector in eq.1 are given in table 1. the speed of ship can be specified by surge velocity ‘u’ and actual shaft velocity ‘n’ from eq. 1 therefore, the sub-model may be presented as in eq. 2 x_prop = [ x (1) x (10)] (2) where  u = x (1) x (1) = 7.  n = x (10)/60 x (10) = 80. 2.2. propeller model the mathematical expression which governs the propulsion speed of the propeller is given in eq. 3 [7] 1 n = (n_c n) m t & (3) where ‘ṅ’ is the output of the propeller as shown in fig 4, ‘n_c’ and ‘n’ are command shaft velocity and actual shaft velocity. 𝑇𝑚 is the time constant for shaft dynamics. motio n forces & moment s linear & angula r vel. positio ns & euler angles surge sway heave roll pitch yaw x y z k m n u v w p q r x y z ϕ θ ψ parameter value unit length 175 meter (m) breath 47.17 meter (m) volume 21,224 meter3 (m3) block coefficient 0.558 no unit ship speed 16 knots propeller speed 80 rev/m abdul qadir (et al.), fuzzy logic based speed controller for a container ship (pp. 45 50) sukkur iba journal of emerging technologies sjet | volume 1 no. 1 january – june 2018 © sukkur iba university 47 3. fuzzy logic controller (flc) the fuzzy logic controller is a method of mapping the input states against the output [10]. fuzzy interface system (fis) as shown in fig. 2 is used to map the given input to required output and this mapping provides basis for decision making [9, 11]. a flc has three stages namely fuzzifier, interface system and defuzzifier. the fuzzifier is a stage where membership functions are mapped, and a truth value is assigned [13]. in interface system stage set of rules is developed and results are generated by each rule, which are then further processed in defuzzifier, where results from rule base are combined to obtain a crisp output [12, 14]. the design of fuzzy logic controller is carried through following steps. 3.1. inputs and outputs for controller the speed of a ship is the function of the shaft speed. the other parameters which are affected by shaft speed are surge velocity ‘u’ and actual shaft velocity ‘n’. therefore, the inputs are speed error (u_error) and shaft speed error (n_error) whereas the output is selected as command shaft velocity (n_c). fuzzy logic controller uses the expert knowledge in the form of linguistic rules. the ranges are tuned by trial and error method. finally, the ranges given in table 3 yielded the satisfactory performance and the values of fuzzified variables are given in table 4, table 5 and table 6 respectively. table 3. ranges of input and output. 3.2. fuzzification of inputs and outputs fuzzification is the method of translating the fixed single in fuzzy variables. during the process of fuzzification the inputs and output defined by a linguistic word are divided into subsets. all the input and output subsets are mapped into fuzzy sets taking definite membership functions as shown in fig. 3. in input vector (𝑋𝑒𝑟𝑟𝑜𝑟) speed error u_error -0.07 to 0.01 shaft speed error n_error -0.03 to 4.6 output (n_c) command shaft speed n_c -0.09 to 155 fig. 1. body fixed reference frame. fig. 2. fuzzy interface system. abdul qadir (et al.), fuzzy logic based speed controller for a container ship (pp. 45 50) sukkur iba journal of emerging technologies sjet | volume 1 no. 1 january – june 2018 © sukkur iba university 48 this research 5 sub-sets are defined for input and output, labelled as: big negative (bn), small negative (sn), zero error (ze), big positive (bp) and small positive (sp). each of these subsets is presented in a way that their values intersect each other as given in table 4, table 5 and table 6. each of subsets is mapped into triangular membership function. table 4. fuzzy variables and subsets of (u_error). fuzzy subsets (u_error) a b c bn -0.2 -0.0798 0.06005 sn -0.0798 0.06005 0.04003 ze -0.06005 0.04003 0.01995 bp -0.04003 0.01995 0.00028 sp -0.01995 0.00028 0.02 table 5. fuzzy variables and subsets of (ṅ_error). table 6. fuzzy variables and subsets of (u_c). 3.3. defuzzification defuzzification is a method to convert the collected output of the linguistic rules into single output value [12]. the maximum degree, average of weight or center of gravity method of defuzzification can be used. for this work centroid defuzzification method is used due to its simplicity and less computation. the mathematical representation of centroid defuzzification method is given in eq. 4 [9,10] (n).n. n u_c (n) n c c d d      (4) where u_c is the single output value, µc(n) is the combined membership function and n is the output variable. fuzzy subsets (n_c) a b c bn 0.5 24.98 49.96 sn 24.98 49.96 74.96 ze 49.96 74.96 99.98 bp 74.96 99.98 124.8 sp 99.98 124.8 140 fuzzy subsets (ṅ_error) a b c bn -0.05 0.8006 1.633 sn 0.8006 1.633 2.49 ze 1.633 2.47 3.334 bp 2.47 3.334 4.158 sp 3.334 4.158 4.5 fig. 4. fuzzy logic controller. fig. 3. mapping of subsets. abdul qadir (et al.), fuzzy logic based speed controller for a container ship (pp. 45 50) sukkur iba journal of emerging technologies sjet | volume 1 no. 1 january – june 2018 © sukkur iba university 49 4. simulation of flc the simulations are carried out by a close lope control as shown in fig. 4. the performance of controller was tried in calm sea ideal conditions as well as with disturbances (wind generated waves). the simulation results are presented in the fig. 5 and fig. 6. 4.1. performance of controller without disturbances the container ship speed controller designed in this research is asked to track the set speed value 8.5 m/s as the input signal for the flc controller with propeller speed (n) of 80 rpm. in ideal conditions (without disturbances) the actual speed (blue line) tracking the desired speed (dashed red line) value with minimal steady state error up to -1 and within 350 seconds the actual speed overlaps desired speed value as steady state error becomes 0. the simulations are carried out on mtalb software and the results are presented in error! reference source not found.. fig. 5. simulation of controller in ideal calm se conditions. 4.2. performance of controller with disturbances the sea conditions are highly dynamic and time variant. there are many disturbances acting on sea ships, i.e, sea currents, depth of water, density of water and wind generated waves etc. in this research wind generated waves are taken as disturbances and the response of controller is tested. the effect of waves can be seen on propeller speed in terms of oscillations, where propeller is trying to overcome the effect of waves to maintain the ship speed. the controller has successfully maintained the ship speed with less than -0.1 error and the propeller speed is stable within 350 seconds. the simulation results are presented in fig. 6. fig. 6. simulation of controller with disturbances. 5. conclusion due to the complex and non-linear behavior of sea, mathematical modeling of ship maneuvering is difficult. therefore, expert knowledge based fuzzy logic control system is designed for container ship speed. the controller is tested with calm sea (ideal) conditions and with wind generated waves as disturbances. the designed controller has remained robust and successfully traced the 0 100 200 300 400 500 6 8 10 u 0 100 200 300 400 500 -1 -0.5 0 u e r r o r 0 100 200 300 400 500 60 80 100 n 0 100 200 300 400 500 6 8 10 u 0 100 200 300 400 500 -0.2 0 0.2 u e rr o r 0 100 200 300 400 500 40 60 80 n abdul qadir (et al.), fuzzy logic based speed controller for a container ship (pp. 45 50) sukkur iba journal of emerging technologies sjet | volume 1 no. 1 january – june 2018 © sukkur iba university 50 desired speed values with and without disturbances. references [1] l. luo, l. gao, and h. fu, “the control and modeling of diesel generator set in electric propulsion ship,” international journal of information technology and computer science (ijitcs), vol. 3, pp. 31, 2011. [2] y. luo, s. lv, s. kang, and x. duan, "combined power and rotating speed control of ship electrical propulsion system in waves," international conference on information and automation (icia), 2012, pp. 200-205. [3] g. rigatos and s. tzafestas, “adaptive fuzzy control for the ship steering problem,” mechatronics, vol.16, pp. 479489, 2006. [4] w. meng, l. h. sheng, m. qing, and b. g. rong, “intelligent control algorithm for ship dynamic positioning,” archives of control sciences, vol. 24, pp. 479-497, 2014. [5] t. szelangiewicz, b. wiśniewski, and k. żelazny, “the influence of wind, wave and loading condition on total resistance and speed of the vessel,” polish maritime research, vol. 21, pp. 61-67 10.2478/pomr-2014-0031. [6] m. n. farouk, s. enzhe, m. a.xiuzhen, “ d6114 diesel engine speed control: a case between pid controller and fuzzy logic controller,” proceedings of 2014 ieee international conference on mechatronics and automation, august 3 6, tianjin, china. [7] q. sun, j. chen, “speed governor design based on fuzzy self-tuning pid method for marine diesel engine,” 5th international conference on advanced design and manufacturing engineering (icadme 2015). [8] t. i. fossen, guidance and control of ocean vehicles. john wiley and sons., 1994, isbn 0 471 94113 pp.445. [9] b. purwahyudi and h. a. saidah, “fuzzy logic controller for volts/hz induction motor control used in electrically driven marine propeller,” issn-l: 2223-9553, issn: 2223-9944 vol. 4 no. 5 september 2013. [10] y. yang and c. zhou, “adaptive fuzzy control of ship autopilot with uncertain nonlinear systems,” proceedings of ieee conference on cybernetics and intelligent systems, singapore, 2004. [11] s. dick, “toward complex fuzzy logic, fuzzy systems,” eee transactions on fuzzy systems, vol. 13, no. 3, pp. 405 – 414, 2005. [12] m. jamshaid, a. titli, l. a. zadeh, and s. boverie, “application of fuzzy logic,” environmental and intelligent manufacturing series, 1997. [13] m. santos, r. lopez, and cruz de la j.m., “a neuro-fuzzy approach to fast ferry vertical motion modelling,” artificial intelligence, 2006, vol.19, pp. 313-321. format template vol. 4, no. 1 | januay june 2021 sjet | p-issn: 2616-7069 |e-issn: 2617-3115 | vol. 4 no. 1 january – june 2021 67 analysis of harmonic distortion reduction through modular multi-level inverter using nearest level modulation (nlm) control strategy syed m. baqar shah1, mazhar hussain baloch1, amir mahmood soomro2 shafqat hussain memon1, dur muhammad soomro3 abstract: the research paper presents the novel control strategy of modular multilevel converter (mmc) to reduce total harmonic distortion (thd) losses by the implementation of nearest level modulation (nlm) control technique. however, the mmc strategy reduces the thd in comparison with the conventional converters which results in improvement of power quality. in addition to this, the mmc has been designed with higher scalability with high voltage and power capacity. sub-module is an integral part of mmc which is built up as an identical and controllable part of it. this type of converter is also known as a controllable voltage source (cvs) converter. many researchers have conducted a detailed review regarding control methods and necessary operations applied to mmc-based systems which can be applied for high voltage direct current (hvdc), particularly focusing to reduce the thd. power converters use many modulation techniques, but the existing techniques contribute to major switching losses. however, in this paper authors discussed in detail about mmc up to 49 levels, by implementing the nlm technique, it is showed that the mmc offers simplicity and good controllability in the thd reductio. in this work, the reduction of thd by increasing the voltage levels in mmc is comprehensively analyzed. the simulation results obtained through matlab/simulink are used to analyze the effectiveness of the proposed control strategy for stable operation of mmc used in hvdc applications. keywords: mmc; nlm; thd; power quality analysis; hvdc; matlab/simulink 1department of electrical engineering, muet szab campus khairpur mir’s, sindh, pakistan 2department of electrical engineering, muet main campus jamshoro, sindh, pakistan 3department of electrical engineering, uthm, malaysia. corresponding author: mazharhussain@muetkhp.edu.pk _________________________________ 1. introduction the modular multilevel converter (mmc) belongs to the multilevel converters’ family [13]. it has attracted substantial interest owing to its various unique features including multiple output voltage levels, higher flexibility, and modular design scalability, capacitor-less dclink as well as transformer-less operations [34]. the mmc has become the futuristic and preferred choice for hvdc applications due to having high redundancy, least cost, lower size of the filter, and low power semiconductor losses. the circuit topology of mmc is shown in fig. 1. the inverter is one of the types of power electronic converters which converts direct current (dc) power supply to alternating current (ac) waveform. inverters are usually used in solar panels and other sorts of devices to use dc power into powering mailto:mazharhussain@muetkhp.edu.pk syed m. baqar shah (et al.), analysis of harmonic distortion reduction through modular multi-level inverter using nearest level modulation (nlm) control strategy (pp. 67-79) sukkur iba journal of emerging technologies sjet | vol. 4 no. 1 january – june 2021 68 some useful ac loads. the output of the inverter depends upon its type which is being used. it can be a square wave, quasi-squarewave, or sine-wave inverter. even if a sinewave inverter is being used, its output is not purely sinusoidal as it contains some harmonics. these harmonics are the components of a periodic wave that are multiple of the fundamental frequency and produce distortion in the output [4-5]. fig. 1: circuit topology these harmonic distortions can be minimized by using a suitable modulation technique or by using the suitable converter topology. modular multilevel converters involves large number of levels with higher efficiency and lesser harmonic distortions [4] [5]. they can manage high voltage operations without involvement series-connecting switching devices. they provide lower common-mode voltages and higher power quality. they offer various advantages i.e. high modularity & scalability, transformer-less operation, lesser switching losses, and lower filtering cost [6]. 2. modular multilevel converter it includes arms consisting of the upper and lower arm. each arm has submodules (sm), and each is linked in the series [6] [7]. the upper arms and lower arms are connected to an inductor and a resistor to control fault current due to the potential difference that appeared in upper arms or lower arms [8]. the capacitor is placed in each submodule while each submodule consists of a half-bridge circuit to get a particular desired voltage level [9]. also, each switch involves a diode in parallel to it intending to control the current flow. the working principle and generation of output levels of mmc can be understood by applying kvl to the basic structure of the circuit as shown in fig. 2. fig. 2: basic structure of mmc where, vdc is a supplied dc voltage, vm [1-4] is a voltage across submodules and vo is the output voltage. by neglecting arm inductance and assuming the capacitors as dc sources, kvl is applied on upper and lower arms rspectively. for the upper arm: 𝑉𝑜 = 𝑉𝑑𝑐 2 − 𝑉𝑚1 − 𝑉𝑚2 (1) for the lower arm: 𝑉𝑜 = − 𝑉𝑑𝑐 2 + 𝑉𝑚3 + 𝑉𝑚4 (2) the voltage vo = vdc/2 can be calculated by bypassing two modules at the upper top and linking both modules in the lower loop. the potential of vo = -vdc/2 can be achieved by connecting both upper modules and bypassing two lower modules [10]. similarly, to achieve zero levels, bypass one module from both the upper and lower loops. this can be achieved in four different ways. in this way, the output syed m. baqar shah (et al.), analysis of harmonic distortion reduction through modular multi-level inverter using nearest level modulation (nlm) control strategy (pp. 67-79) sukkur iba journal of emerging technologies sjet | vol. 4 no. 1 january – june 2021 69 voltage levels are generated corresponding to each loop. the submodule operation has three states; each is described in table i. table i: summary of the operation of sms 2.1. cell structure the literature proposes different types of submodule configurations. following are the most well-known cell configurations: half-bridge submodule cell is the basic and the most common cell configuration in all sms configurations due to its only two switching devices. if the upper switch s1 is operating its conduction, sm is in the “on” state. interchangeably, if the lower switch s2 is operating its conduction, sm remains in an “off” state. the output voltage of a cell is equal to sm capacitor voltage that depends on the switching operation of s1 and s2 as shown in fig. 3. fig. 3: half-bridge sm cell full-bridge submodule (fbsm) cell configuration contains four switching devices, and its output voltage is equal to the voltage of the capacitor, which depends on the switching operation of switching devices, as shown in fig. 4. fig. 4: full-bridge sm cell clamp-double sm (cdsm) configuration has two half-bridge sms, one extra transistor with connected diodes, and additional diodes, as shown in fig. 5. the switch s5 remains always in the “on” state, and this configuration operates like two series-connected half-bridge sms. fig. 5: clamp-double sm cell clamp-single sm (cssm) consists of three switching devices with its parallelconnected diodes, a capacitor, and an extra diode, as shown in fig. 6. states sm 1 sm 2 d1 d2 capacito r blockin g state off off on of f of f on inserted not inserted cut-in state on off inserted cut-off state off on not inserted syed m. baqar shah (et al.), analysis of harmonic distortion reduction through modular multi-level inverter using nearest level modulation (nlm) control strategy (pp. 67-79) sukkur iba journal of emerging technologies sjet | vol. 4 no. 1 january – june 2021 70 fig. 6: clamp-single sm cell apart from these sm topologies, many topologies of sms are also present in literature [9] & [12]. in this paper, the most common and basic building block, half-bridge configuration, is discussed in the rest of the section. 3. modulation technique modulation technique plays a vital role in the proper working, performance and efficiency f the converter. by using different pwm techniques, the levels of output can vary as per the desired requirement and application [11] [12]. the techniques of sinusoidal pwm are very common and used as control techniques, and they are additionally categorized into level-shifted and phaseshifted pwm techniques. other variations of the level-shifted pwm techniques include inphase deposition (ipd), phase-opposite deposition (pod), and alternate-phase opposite deposition (apod). these techniques use sine wave and different triangular waves, these are then compared to generate different levels of output voltages [13]. as there are many waves compared so this contributes to more switching losses. the nearest level modulation (nlm) technique is an alternative method for carrierbased modulation techniques that utilizes more waves [14]. it has the advantage of being simple for implementation. it was introduced mainly for large-drive multilevel systems, but it can also be used for mmc-based hvdc applications as it is more flexible and provides easy digital implementation when the converter is operating at a higher number of levels. it is used to avoid the triangular-carrier waves and directly computes the states of switching and duty cycles [15] [16]. the main idea behind this is to sample the reference at frequency fs and then approximate it to the nearest level which results in the natural fundamental switching frequency with fewer switching losses. for an mmc of n sub-modules per arm, nlm produces an n+1 output voltage level. if the converter operates at a higher frequency it will generate a better reference signal in terms of approximation. now the reference waveform becomes a staircase, and the lower levels are used longer than the higher ones and hence this leads to the unbalance of capacitor voltage [17]. therefore, nlm is not suitable for directly assigning to the sub-modules, instead, it requires a sorting algorithm before it is fed to the converter to ensure submodule energy balance. fig. 7 shows the block diagram and the working of nlm. the block diagram shows that at first the reference voltage is normalized with the capacitor voltage of the submodule in the gain block then the round-function generates the closest integer number of the submodules to insert to approximate the reference voltage with the nearest voltage level [17] [18]. fig. 7: block diagram & working principle of nlm. syed m. baqar shah (et al.), analysis of harmonic distortion reduction through modular multi-level inverter using nearest level modulation (nlm) control strategy (pp. 67-79) sukkur iba journal of emerging technologies sjet | vol. 4 no. 1 january – june 2021 71 4. 49 levels (h-bridge) modular multilevel converter the matlab model of a three-phase circuit of mmc is shown in fig. 8. rl load is connected at the grid side (ac side). the number of levels is varied to analyze the impact on the total harmonic distortion (thd) and on the smoothness of output waveform. thd loss can be mitigated by inserting submodules in the converter [19]. submodules are increased up to 49 output voltage levels. hence, thd loss mitigation mainly contributes in power quality improvement [20]. the results are presented in the comparative analysis section for different levels including 22, 28, 33, 41, and 49 levels with rl load. 5. results and discussion comparative result analysis of multiple levels for (h-bridge) mmc is done by using matlab/simulink software (2018b). the output voltages and currents are compared concerning total harmonic distortion for 22, 28, 31, 41, and 49 levels. 5.1. case 1: 22 levels in this case, 22 level mmc, the output voltage & thd are shown in fig. 9 & 10 respectively, and the output current & thd are shown in fig. 11 & 12 respectively. at this stage, output voltage and current waveforms are not sinusoidal, they contain harmonics and the value of voltage harmonics is 2.58% with a fundamental frequency of 50 hz. and the current thd is 0.94%. 5.2. case 2: 49 levels in this case, mmc is increased up to 49, the output voltage and current waveforms become very smooth and closer to sinusoidal. the total harmonics distortion is reduced to a certain value. the output voltage and thd are shown in fig. 13 & 14 respectively, and the output current & thd are shown in fig. 15 & 16 respectively. the drastic reduction in voltage and current thd can be seen in the waveforms. almost 56% of thd is reduced by an increasing number of levels. this also fulfils ieee 519 standard about harmonics current and voltage limits. the comparative result analysis has showed that 49 levels of mmc is having lesser thd in the output as compared with other mmc levels such as 22, 28, 31, and 41. as the number of levels increases, it means more submodules are being inserted and the converter produces a highly sinusoidal waveform at its output side. more levels contribute to decreasing instantaneous error, the converter generates the desired waveform, which is very close to the sinusoidal waveform. the summarized results of the comparative analysis are given in table ii and fig 1. syed m. baqar shah (et al.), analysis of harmonic distortion reduction through modular multi-level inverter using nearest level modulation (nlm) control strategy (pp. 67-79) sukkur iba journal of emerging technologies sjet | vol. 4 no. 1 january – june 2021 72 fig. 8: three-phase mmc based circuit model fig. 9: three-phase output voltage for 22-level mmc with rl load (2.58% thd) syed m. baqar shah (et al.), analysis of harmonic distortion reduction through modular multi-level inverter using nearest level modulation (nlm) control strategy (pp. 67-79) sukkur iba journal of emerging technologies sjet | vol. 4 no. 1 january – june 2021 73 fig. 10: three-phase output voltage thd for 22-level mmc with rl load fig. 11: three-phase output current for 22-level mmc with rl load (0.94% thd) syed m. baqar shah (et al.), analysis of harmonic distortion reduction through modular multi-level inverter using nearest level modulation (nlm) control strategy (pp. 67-79) sukkur iba journal of emerging technologies sjet | vol. 4 no. 1 january – june 2021 74 fig. 12: three-phase output current thd for 22-level mmc with rl load fig. 13: three-phase output voltage for 49-level mmc with rl load (1.13% thd) syed m. baqar shah (et al.), analysis of harmonic distortion reduction through modular multi-level inverter using nearest level modulation (nlm) control strategy (pp. 67-79) sukkur iba journal of emerging technologies sjet | vol. 4 no. 1 january – june 2021 75 fig. 14: three-phase output voltage thd for 49-level mmc with rl load fig. 15: three-phase output current for 49-level mmc with rl load (0.27% thd) syed m. baqar shah (et al.), analysis of harmonic distortion reduction through modular multi-level inverter using nearest level modulation (nlm) control strategy (pp. 67-79) sukkur iba journal of emerging technologies sjet | vol. 4 no. 1 january – june 2021 76 fig. 16: three-phase output current thd for 49-level mmc with rl load table ii. summarized results of the analysis of thd submodules (upper/lower arm) levels voltage thd current thd 7 8 8.11% 5.36% 21 22 2.58% 0.94% 27 28 2% 0.64% 32 33 1.69% 0.49% 40 41 1.35% 0.34% 48 49 1.13% 0.27% syed m. baqar shah (et al.), analysis of harmonic distortion reduction through modular multi-level inverter using nearest level modulation (nlm) control strategy (pp. 67-79) sukkur iba journal of emerging technologies sjet | vol. 4 no. 1 january – june 2021 77 graph i: summarized results of the analysis of thd 6. conclusion it is concluded for obtained simulation results that modular multilevel converter with h-bridge sm configuration produces less total harmonics distortion (thd) when it is used with nearest level modulation (nlm) control technique. it is further, analyzed that (mmc) through the nlm modulation technique is found better in achieving very minimum thd as compared to the conventional inverters/ converters. however, in this work, the thd is reduced to 0.02% approximately with increased levels up to 49, which results in mitigation of harmonics distortion and improved voltage and current waveforms at the output side. mmc leads to various applications where the proposed mmc-based hvdc structure can be used to replace conventional power networks, particularly for hvdc systems. author contribution all authors contributed equally to the work. data availability statement conflict of interest the authors declare no conflict of interest. funding not applicable. acknowledgment not applicable. references [1] beheshti, n., rezanejad, m., & mehrasa, m. “linearized control technique with lyapunov function-based compensators for mmc-based hvdc system under load variation and fault condition”, international journal of electrical power syed m. baqar shah (et al.), analysis of harmonic distortion reduction through modular multi-level inverter using nearest level modulation (nlm) control strategy (pp. 67-79) sukkur iba journal of emerging technologies sjet | vol. 4 no. 1 january – june 2021 78 & energy systems, vol. 124, 106333. doi:10.1016/j.ijepes.2021. [2] mohammed alharbi, semih isik “an optimized sm fault-tolerant control method for mmc-based hvdc applications”,2019 ieee energy conversion congress and exposition (ecce), 28 november 2019. [3] hu p, jiang d. “a level-increased nearest level modulation method for modular multilevel converters”, ieee transactions on power electronics. 2015 apr; 30(4):1836-1842. [4] m. kumar, et.al” an overview of uninterruptible power supply system with total harmonic analysis & mitigation: an experimental investigation for renewable energy applications “, international journal of computer science and network security, vol.18, issue 6, 2018. [5] wu d, peng l. “characteristics of nearest level modulation method with circulating current control for modular multilevel converter”, iet power electronics. 2016 feb 10;9(2):155-64. [6] soomro, dur muhammad, et al. "optimal design of a single-phase apf based on pq theory." international journal of power electronics and drive systems 11.3 (2020): 1360. [7] b.l nayak, g. venkataratnam “ thd and switching losses analysis of multi-level inverter fed 3φ induction motor drive”, international journal of scientific and engineering research, vol. 5, issue 1,pp 2067-2074” [8] soomro, dur muhammad, et al. "mitigation of voltage sag caused by unbalanced load by using dft controlled dvr." 2019 ieee international conference on innovative research and development (icird). ieee, 2019. [9] y.m park, h.s ryu, h.y lee, m.g jung and s.h lee “design of cascaded hbridge multilevel inverter based on power electronics building blocks and control for high performance”, journal of power electronics, vol. 10, no. 3, may 2010. [10] s. kouro, k. gopakumar, j. pou “recent advances and industrial applications of multilevel converters”, ieee transaction on industrial electronics, vol. 57, no. 8, august 2010. [11]tahir, sohaib, et al. "robust digital deadbeat control design technique for 3 phase vsi with disturbance observer." ieice electronics express (2017): 14-20170351. [12] tahir, sohaib, et al. "digital control techniques based on voltage source inverters in renewable energy applications: a review." electronics 7.2 (2018): 18. [13] b. harish, u.r kiran, b.m lal and s.k dash “power quality improvement of dc-ac converter by using cascaded hbridge multilevel inverter”, international journal of advanced research in electrical, electronics and instrumentation engineering, vol. 3, issue. 2, feb 2014. [14] d. subramanian, r. rasheed “modified multilevel inverter topology for driving a single-phase induction motor”, international journal of advanced research in electrical, electronics and instrumentation engineering, vol. 2, issue. 1, dec 2013. [15]nadeem, muhammad haroon, et al. "transient harmonic voltage based protection scheme for multi-terminal hvdc transmission networks." 2019 ieee international conference on industrial technology (icit). ieee, 2019. [16] memon, abdul hakeem, et al. "achieving high input pf for crm buck-buck/boost pfc converter." ieee access 6 (2018): 79082-79093. [17]ahmad, muhammad, et al. "hvdc transmission an outlook and significance for pakistani power sector." iop conference series: earth and environmental science. vol. 133. no. 1. iop publishing, 2018. https://www.researchgate.net/profile/mahendar_kumar5/publication/326449978_an_overview_of_uninterruptible_power_supply_system_with_total_harmonic_analysis_mitigation_an_experimental_investigation_for_renewable_energy_applications/links/5b4e374545851507a7a99294/an-overview-of-uninterruptible-power-supply-system-with-total-harmonic-analysis-mitigation-an-experimental-investigation-for-renewable-energy-applications.pdf https://www.researchgate.net/profile/mahendar_kumar5/publication/326449978_an_overview_of_uninterruptible_power_supply_system_with_total_harmonic_analysis_mitigation_an_experimental_investigation_for_renewable_energy_applications/links/5b4e374545851507a7a99294/an-overview-of-uninterruptible-power-supply-system-with-total-harmonic-analysis-mitigation-an-experimental-investigation-for-renewable-energy-applications.pdf https://www.researchgate.net/profile/mahendar_kumar5/publication/326449978_an_overview_of_uninterruptible_power_supply_system_with_total_harmonic_analysis_mitigation_an_experimental_investigation_for_renewable_energy_applications/links/5b4e374545851507a7a99294/an-overview-of-uninterruptible-power-supply-system-with-total-harmonic-analysis-mitigation-an-experimental-investigation-for-renewable-energy-applications.pdf https://www.researchgate.net/profile/mahendar_kumar5/publication/326449978_an_overview_of_uninterruptible_power_supply_system_with_total_harmonic_analysis_mitigation_an_experimental_investigation_for_renewable_energy_applications/links/5b4e374545851507a7a99294/an-overview-of-uninterruptible-power-supply-system-with-total-harmonic-analysis-mitigation-an-experimental-investigation-for-renewable-energy-applications.pdf https://www.researchgate.net/profile/mahendar_kumar5/publication/326449978_an_overview_of_uninterruptible_power_supply_system_with_total_harmonic_analysis_mitigation_an_experimental_investigation_for_renewable_energy_applications/links/5b4e374545851507a7a99294/an-overview-of-uninterruptible-power-supply-system-with-total-harmonic-analysis-mitigation-an-experimental-investigation-for-renewable-energy-applications.pdf https://www.researchgate.net/profile/mahendar_kumar5/publication/326449978_an_overview_of_uninterruptible_power_supply_system_with_total_harmonic_analysis_mitigation_an_experimental_investigation_for_renewable_energy_applications/links/5b4e374545851507a7a99294/an-overview-of-uninterruptible-power-supply-system-with-total-harmonic-analysis-mitigation-an-experimental-investigation-for-renewable-energy-applications.pdf syed m. baqar shah (et al.), analysis of harmonic distortion reduction through modular multi-level inverter using nearest level modulation (nlm) control strategy (pp. 67-79) sukkur iba journal of emerging technologies sjet | vol. 4 no. 1 january – june 2021 79 [18] s. ali, z. ling, k. tian and z. huang, "recent advancements in submodule topologies and applications of mmc," in ieee journal of emerging and selected topics in power electronics, doi: 10.1109/jestpe.2020.2990689. [19] fatemeh shahnazian et.al., “control of mmc-based statcom as an effective interface between energy sources and the power grid”, electronics 2019, 8(11), 1264; https://doi.org/10.3390/electronics 8111264 [20] memon, s.h., kumar, m., memon, a.h., memon, z.a. and soomro, s.a., 2018. total harmonic distortion (thd) analysis of grid integrated permanent magnet synchronous generator (pmsg) with full scale converter (fsc) based wind farm’’. ijcsns, 18(12), p.232. https://doi.org/10.3390/electronics%208111264 https://doi.org/10.3390/electronics%208111264 a system analysis approach to visual object tracking vol. 3, no. 1 | january june 2020 sjet | issn: 2616-7069 | vol. 3 | no. 1 | © 2020 sukkur iba university 37` a system analysis approach to visual object tracking obaid ahmed khan1, ahmed saeed1 abstract: in the modern-day study of system behavior and analysis, understanding the response of how the system will behave in a certain condition is considered vital. thus, keeping object behavior as the primary objective and object detection as a core instrument this project intends to identify the object and track the motion of the desired object. this paper provides an overview of how a closed-loop controlbased system was designed using a camera as visual input. the video signal is analyzed to detect distinct color and shape similarities to the desired object. based on a high similarity index the raspberry pi controller generates a pulse width modulation signal to regulate the angular position of the rotary actuator to align the camera frame of view according to a desired object’s position. post system design experimentation results and potential realized system faults are expressed within the conclusion. keywords: computer vision, object tracking, closed-loop control system, system analysis. 1. introduction: computer vision analysis of object characteristics and their behavior has always been a topic that has found a lot of success in the scientific community. the first studies date back all the way to the 1700s when electronic devices started getting more powerful. it was during this era the fundamental basics of how we can analyze objects were understood through applications in the field of medicine [1] [2]. while this was an amazing feat these techniques could not be applied towards the field of object detection due to the lack of computing power required for such a task. while the technology was not ready yet many techniques for detection of object characteristics were being studied [3]. soon specialized computing devices were put into practice that allowed users to process images and apply pattern recognition techniques [4]. 1 dha suffa univeristy karachi, pakistan corresponding author: obaid_10@live.com the implementation of these techniques meant that users can improve the previously existing techniques and algorithms to design better and more robust applications. one of these applications was the amalgamation of the control theory and computer vision. this led to many applications towards military, road control, and filmography [5] [6]. application of this amalgamation between control theory and computer vision has been most prevalent in the field of automation. one such application of this technology in the automation is object tracking. object tracking is the tracking of a specific object possessing desired characteristics using movable visual sensors. this concept of tracking objects through vision is not rather new with it being a crucial part of human development for years and with most infants having developed this ability soon after birth [7]. obaid ahmed (et al.) a system analysis approach to visual object tracking (pp. 37 43) sjet | issn: 2616-7069 | vol. 3 | no. 1 | © 2020 sukkur iba university 38` 2. state of the art research in the area of computer vision is quite dense with a lot of studies conducted towards efficient algorithm techniques. some of these notable techniques can be consulted in [8]. this documentation analyzed the vast literature of computer vision and only the most wellestablished techniques were pondered on that have been physically realized. based on an in-depth analysis of the literature it was found that there is a lack of quality of quantitative work towards the application of computer vision in the field of automation and control. some note-worthy efforts that have been made were either with a fixed viewpoint [9] or if the viewpoint was movable the system lacked an essential effort towards the incorporation of an efficient automation control strategy [10]. to overcome the issues plaguing object detection the system was designed with a control systems point of view. 3. methodology the ability to analyze objects visually and take actions accordingly are the features of smart controlling and when it is being developed for computing devices it needs to be developed in two steps. the first being object detection which involves the identification of the desired target and the second is object tracking, where the system reacts to the visual data. a. object detection the first step for object tracking is object detection or the ability to detect a specific object. in [11] the basic technique of object detection is considered using color threshold method in which a basic array of rgb code is set, after which the code is compared with each individual pixel within the frame processing the image into binary setting white to the rgb code threshold and black to other code converting the image into a black and white image sending the required colors code to the processor. this is further improved upon [12] by involving canny edge detection for the detection of edges by convolving a raw unprocessed image with a gaussian filter resulting in a blurry image with no noticeable noise. b. object tracking to track the object, a basic control structure that would enable the controller to efficiently control the position of the system was designed. in this regard, an error reduction technique is used. since the object tracking is based on error reduction so the error is the difference between the center of the screen frame and the center of the object. the setpoint i.e. object center was calculated using hough transform [13] whereas, the process variable is the frame center which is calculated by dividing the screen resolution into half. the error is calculated in terms of the pixels’ difference. so, in order to calculate the center of the screen measure the screen resolution, the screen used in this experiment is 720x1280p and divide the pixels into half to get the center of the screen which is (640,360). fig 1: frame of reference 𝐷𝑢𝑡𝑦𝐶𝑦𝑐𝑙𝑒% = ((𝑥 ∗ 𝑂𝑛 𝑇𝑖𝑚𝑒) + 𝑏𝑖𝑎𝑠) ∗ 𝑇𝑖𝑚𝑒 𝑖𝑛𝑡𝑒𝑟𝑣𝑎𝑙 where, on-time = total pulse duration for servo movement between 0-180 degrees in ms. bias = the minimum pulse duration required for the servo to become active in ms. time interval = time in ms. x = the calculated ratio between time intervals and pulse width for achieving the desired angle. obaid ahmed (et al.) a system analysis approach to visual object tracking (pp. 37 43) sjet | issn: 2616-7069 | vol. 3 | no. 1 | © 2020 sukkur iba university 39` 4. system modeling a. control system the basic control structure could not be directly employed without the system model. to understand the system, model the hardware specifications were initially explored. based on hardware specifications (given in table 1) it was speculated that the most appropriate control structure for the system would be a proportional controller design. table 1: servo motor specifications weight (g) 9 torque (kg) 1.8 speed (sec/60deg) 0.1 dead bandwidth 1 us temperature range 0 c – 55 c operating voltage 4.8 v stall torque 1.8kg/cm dimension 23 x 12.2 x 29mm gear type pom gear set to test the hypothesis of the desired control, structure a system response analysis was conducted:  system response analysis to record the input-output data, an excitation signal is sent through the system. using this data, a plant model is built, and based on plant model accuracy the system model is tuned to achieve a quick and stable response. after analyzing system response data, it was realized that a second-order model was the most appropriate for the system. exploring the previous hypothesis merits of each controller design were compared which led to the use of p controller, compared to pd and pid controllers the system response using a proportional controller is much faster which is a major requirement of the system design [14] in p controller the p is proportional to the value generated of the error between setpoint and process variable. p controller is used in the first-order system by optimizing the transient behavior by reducing the steady-state error of the system. the gain k is inversely proportional to the steady-state error, as one of them increases the other decreases and vice versa. this controller is only applicable when the steady-state error is in the applicable range. b. system identification fig 3: graph plotted between duty cycle and position the slope of the graph measured is 13.53. fig 2: block diagram of control system obaid ahmed (et al.) a system analysis approach to visual object tracking (pp. 37 43) sjet | issn: 2616-7069 | vol. 3 | no. 1 | © 2020 sukkur iba university 40` 𝐺(𝑠) = δ𝑦 δ𝑥 𝑑𝜃 𝑑𝑥 = 13.53 where 𝑦(𝑥 ) = (𝑝𝑜𝑠𝑖𝑡𝑖𝑜𝑛) ; 𝑥 = % duty cycle; the laplace transform equation of the system was modeled as, ℒ[𝑦(𝑥)](𝑠) = 13.53x(s) 𝑠 assuming 𝑦(0) = 0 initially 𝑦(𝑠) = 13.53𝑥(𝑠) 𝑠2 𝑦(𝑥) = 𝑐1 + 13.53𝑥 5. algorithm the algorithm initiates the camera draws a new frame and scans the surrounding for the desired object. depending on the yaw motor movement the algorithm decides whether to turn right or left. the program goes into tracking state when the desired object is the detected and after feature extraction proceeds with tracking of the object. the frame is updated in real-time tracking objects' current position. fig 4: algorithm flow chart a. experimentation the experiment included the physical model implantation of the above mention algorithm and constructed a system consisting of a raspberry pi 3 model b and two high fidelity servo motors with a specified control structure. the first motor acted as the yaw rotational motor and the other acted as the pitch rotational motor. then a webcam was installed on the top of the pitch rotational servo motor and a series of trials were conducted using an object. b. calibration the object was placed first directly in front of the system to identify if any bias errors are present so that these can be calibrated out of the final working model. the system showed no presence of any bias error and would remain constantly stuck with the center of the view frame locked at the calculated cylinder center but with small bias. c. sensitivity analysis the object was then moved to identify whether the algorithm adapts to the input change, at small error values the system would quickly adapt to the change and reposition the view frame to the correct value with negligible error. the problem arose when the system was presented very high. fig 5: hardware 6. results the object detection method proposed in [11] was further improved upon by using color thresholding in combination with canny edge detection to find a similarity between the camera image and the desired obaid ahmed (et al.) a system analysis approach to visual object tracking (pp. 37 43) sjet | issn: 2616-7069 | vol. 3 | no. 1 | © 2020 sukkur iba university 41` object. this technique led to the object being detected and tracked very accurately. table 2 shows the optimal timing of the system: table 2: optimal timing of the system timing time is taken t 0 the system turns on and scans the environment 0 ∞ t1 object detected by the system 20 millisecond t2 object tracked with 5% threshold error 4.5 seconds t3 object tracked with high accuracy 1 second t4 an object within steady-state 800 milliseconds t5 system readjusts due to proportional control 1.5 seconds *note: time between t0 and t1 could an infinite amount of time and depends on when the object is introduced in the system. please see figure 8 for an example of the object detected at 0.3 seconds. the methodology described in [11] does lend well to the rapid detection of the object. however, this approach lacks a fundamental feature in distinguishing between different objects with the same color code which results in false object detection. additionally, the design methodology [12] based on canny edge detection focuses on the outer boundary of the object but it can only provide the approximation between similar size objects and fails to extract different features. whereas, the present paper proposes the solution for object detection using a colour threshold in combination with the canny edge detection methodology to bridge the flaws inherited with the two techniques. on the other hand, object tracking using the error reduction method is efficient and consumes low processing power. although there are some minor fluctuations in tracking between error calculation and actual execution, it can be easily removed by introducing deadtime once the error is less than the desired accuracy. fig 6: object detection &tracking fig 7: testing with different objects figure 8 shows error plotting with respect to time which shows that error reduces as the camera approaches towards the desired set point. obaid ahmed (et al.) a system analysis approach to visual object tracking (pp. 37 43) sjet | issn: 2616-7069 | vol. 3 | no. 1 | © 2020 sukkur iba university 42` fig 8: error plotting 7. conclusion & future work the algorithm was then rewritten to include the change and based on further evaluation it was found that most of the sensitivity errors were resolved and the bias was also seemingly removed. the system now with the object even at the farthest end of the view frame could centralize the frame of view of the camera to the object’s position in under 11 milliseconds and could track it smoothly. a problem that was realized during the system implementation was that when the object was static the system would slightly move and reposition itself due to a refresh of the system cache. this issue was fixed by inserting an additional condition in the algorithm when switched off the control actuation whenever the error accumulation of the last 5 values is lower than 0.5. some areas for further research are:  instead of involving the condition of switching off the control actuation, the error could be minimized further but without a severe increase in tracking time. this would require an effort towards optimization of the system by techniques such as branch and bound method.  the control structure was based on a p controller with a 3-point model but in order to achieve the best results a higher polynomial data analysis is required. this would be investigated to further improve the system’s performance. references [1] m. forouzanfar, n. forghani, and m. teshnehlab, "parameter optimization of improved fuzzy c-means clustering algorithm for brain mr image segmentation", engineering applications of artificial intelligence, vol. 23, no. 2, pp. 160-168, 2010. available: 10.1016/j.engappai.2009.10.002.. [2] “a new perspective of wavelet-based image denoising using different wavelet thresholding", international journal of science and research (ijsr), vol. 5, no. 8, pp. 1504-1509, 2016. available: 10.21275/art20161212. [3] r. jarvis, "special feature: an interactive minicomputer laboratory for graphics, image processing, and pattern recognition", computer, vol. 7, no. 10, pp. 49-60, 1974. available: 10.1109/mc.1974.6323334. [4] f.schlag, a. c.sanderson, c. p. neuman, and f. c. wimberly, "implementation of automatic focusing algorithms for a computer vision system with camera control", robotics institute, 1983. [accessed 25 july 2019]. [5] e. dickmanns and a. zapp, "a curvature-based scheme for improving road vehicle guidance by computer vision", mobile robots i, 1987. available: 10.1117/12.937795 [accessed 25 july 2019]. [6] w. miller, "real-time application of neural networks for sensor-based control of robots with vision", ieee transactions on systems, man, and cybernetics, vol. 19, no. 4, pp. 825831, 1989. available: 10.1109/21.35345 [accessed 25 july 2019]. [7] m. moore, r. borton and b. darby, "visual tracking in young infants: evidence for object identity or object permanence?", journal of experimental child psychology, vol. 25, no. 2, pp. 183-198, 1978. available: 10.1016/00220965(78)90076-0 [accessed 25 july 2019] [8] r. jain, r. kasturi and b. schunck, machine vision. new york: mcgrawhill, 1995. [9] b. shao and h. xin, "a real-time computer vision assessment and control of thermal comfort for grouphoused pigs", computers and electronics in agriculture, vol. 62, no. 1, pp. 15-21, 2008. available: obaid ahmed (et al.) a system analysis approach to visual object tracking (pp. 37 43) sjet | issn: 2616-7069 | vol. 3 | no. 1 | © 2020 sukkur iba university 43` 10.1016/j.compag.2007.09.006 [accessed 24 july 2019]. [10] d. lee and y. park, "vision-based remote control system by motion detection and open finger counting," in ieee transactions on consumer electronics, vol. 55, no. 4, pp. 23082313, november 2009. [11] s. jayati singh, "object detection by color threshold method," international journal of advanced research in computer and communication engineering, vol. 4, no. 10, pp. 354-356, 2015 [12] j. canny, "a computational approach to edge detection," ieee transactions on pattern analysis and machine intelligence, vols. pami-8, no. 6, pp. 679 698, 1986 [13] m. rizon and et al., "object detection using circular hough transform," american journal of applied sciences, vol. 2, pp. 1606-1609, 2005. [14] k smriti rao and ravi mishra, “comparative study of p, pi and pid controller for speed control of vsi-fed induction motor” international journal of engineering development and research, vol. no 2, pp 2740-2744, ijedr1402230, 2014. [15] onkar r. kirpan and et al., “object detection on raspberry pi,” international journal of engineering science and computing, vol. 7, no.3, pp. 5360-5362, 2017 [16] vijayalaxmi, et al, “object detection and tracking using image processing,” global journal of advanced engineering technologies, special issue (ctcnsf), pp. 113-115, 2014. [17] b. dinesh, "understanding and design of an arduino-based pid controller,” research master thesis, physics and applied physics, virginia commonwealth univ., va., 2016 [18] katsuhiko ogata, “pid controllers and modified pid controllers,” in modern control engineering, prentice hall, fifth edition, pp. 567-647, 2010. [19] d.chris, “github,” github,inc., 10 october 2015. [online]. available: https://github.com/microcontrollersan dmore/raspberry_pi_2_and_opencv _3_tutorial_part_1. [accessed 13 september 2017]. [20] r.adrian, “pyimagesearch,” 14 september 2015. [online].available: https://ww.pyimagesearch.com/2015/0 9/14/ball-tracking-with-opencv/. [accessed 17 october 2017]. format template vol. 1, no. 1 | january june 2018 sjet | issn: 2616-7069 | vol. 1 | no. 1 | © 2018 sukkur iba 66 design and control of an unmanned ground vehicle for search and rescue missions kamran shahani1, hong song1, chaopeng wu1, syed raza mehdi1, kazim raza1, noorudin khaskheli2 abstract: this paper focuses on the design and control of the unmanned ground vehicle for search and rescue missions. it is operated manually by using xbee remote controller and arduino uno is utilized to guide signals to ugv. this robot has innovations such as to move on rocky surfaces, a robotic arm is fixed on it which will perform pick and place tasks according to the inputs from the operator. the camera is attached for live vision feedback. the custom model designed was experimented with various situation scenarios to test its fidelity. this project is suitable for multiple purposes like monitoring and for military exploration missions. keywords: xbee module; ugv; arduino; wireless control; dc motor; manipulator. 1. introduction an unmanned ground vehicle (ugv) is a vehicle running in touch with the ground, transporting devices, without a human operator presence. the robot can move on the rough grounds and in order to perform various farm duties where the presence of human being inside the area/place is unsafe [1]. to evade trailing of human life, this is more suitable to use the robot for a related job. mostly ugv’s are useful for nowadays for the armed forces especially in the battlefield or war, now a day’s these are also used in different industries for loading and unloading purpose, in nuclear power plants for filling and wasting purpose and in homes, these robots are used as servants [2]. the aim is to get the wireless live visual feedback of the 1ocean optics and automation lab, institute of ocean technology, ocean college, zhejiang university hangzhou 310058, china; 2 institute of coastal engineering, ocean college, zhejiang university corresponding email: 21634142@zju.edu.cn accident cities, find the presence of enemy’s positions, weapons, obstacles and much more information without any distressing they can get it control [3].the ugv can work as rescue robot in rescue organization, rescue organization will quickly and securely receive data of the accident cities, a duty that is both tough and terrible. a review of the development of unmanned ground vehicles in japan from the1970’s to 1990’s is presented in [4].the unmanned ground vehicle for fumigation purpose which designed by the national space research and development agency, abuja nigeria [5]. the vehicle consists of four wheels, uses bluetooth as communication channel and can operated around 8 meters of radius. mailto:21634142@zju.edu.cn kamran shahani (et al.), design and control of unmanned ground vehicle for search and rescue missions (pp. 66 71) sukkur iba journal of emerging technologies sjet | volume 1 no. 1 january – june 2018 © sukkur iba university 67 2. proposed system figure 1 shows the entire proposed system block diagram where the arduino uno microcontroller saves the c code that commands the vehicle, the manipulator drive and the camera. the two direct current (dc) motors drive the vehicle forth, backward, left and right directions, the servo motor controls the movements of manipulator and camera. l298 driver module works as the direct current (dc) motors driver board and the xbee module builds a wireless connection between the surface controller and the vehicle [6]. fig. 1. proposed system block diagram. 2.1. versa chassis body we have built essentially the frame of our vehicle from versa (vex) apparatus [7]. these components are made of a lightweight aluminum sheet. we use this because it saves our lot of time all parts are available we have to just assemble and build the body of a robot. other parts are also available such as a shaft, gears, bearings gripper and many more. on aluminum sheets there are already holes and squares available; the size of these holes is about 0.8cm. for assembling the robot we do not need any welding machine for fixing of components done by using nuts and bolts. figure 2 shows the u, l and c shapes sheets provided by the versa robotics. our vehicle consists of two main parts one is crawler body and the second one is the three degrees of freedom (3-dof) manipulator arm with the gripper. crawler which is the main frame of the vehicle holds tracked wheels, in order to move on the coarse surfaces easily without any difficulty facing. fig. 2. crawler robot and manipulator parts. 2.2. dc geared motor source of moving the vehicle is motor. our ugv consists of two dc gear motors, track wheel drive based robot. dc geared motors are used because they have low speed but high torque [8]. always dc geared motor is used in that type of crawlers or tanks because at hilly or inclined surfaces more torque is needed instead of speed. crawlers motor cannot allow the direct drive to the trackedwheels because these motor’s shaft is a lock or not compatible. in this type of robot special type of wheels are used named as spikey-wheels [9]. table 1 shows the direct current (dc) motor specification of motors. kamran shahani (et al.), design and control of unmanned ground vehicle for search and rescue missions (pp. 66 71) sukkur iba journal of emerging technologies sjet | volume 1 no. 1 january – june 2018 © sukkur iba university 68 table i. dc motor specifications. 2.3. manipulator arm manipulator's assembly is made of aluminum u and l shapes plates. purpose of placing manipulator in the robot is to pick and place the objects from the surface or ground [10]. this manipulator consists of shoulder, wrist, and gripper. shoulder joint which is revolute and rotates about 90 degrees, wrist joint which is twisted joint rotate about 180 degree and last one is gripper whose angle of opening and closing is about 160 degree. joints of manipulator robot are driven by 3 mg 996 servo motors. there are 3 links in this manipulator robot each link is connected with the joint. measurements of links are given below. distance between link 0 to link1 = 96mm (3.7 inch) this part is called shoulder. distance between links 1 to link 2 = 105mm (4.1 inches) this part is called wrist. with link 2 end effector is connected whose opening distance is about 55mm (2.16 inch) figure 3 shows the three degree of freedoms manipulator arm. fig. 3. 3-dof manipulator robot arm. source: www.sainsmart.com/products/3axis-desktop-robotic-arm. 2.4. main controller arduino uno this is the main controller of the vehicle. consist of a microcontroller which saves the program which we write. this main board is operated at 5v dc; we can supply it by 3 methods, through usb cable connected with pc, plug the 5v dc input at its vin pin and connect the ground must and last one which is through external 5-12 dc adapter to a power socket of the arduino. you can give maximum supply 12v dc, 1a current. inside the arduino, there is 7805 voltage regulator used which prevent the board from any damages. figure 4 shows the input and output ports of the arduino uno. no need of soldering the wires user can easily plug the male connecting wires to the female header of arduino uno for communication. fig. 4. arduino uno main controller. source https://www.arduino.cc/ specification explanation voltage rated 12 v stall current 5.5 a no load current 0.16 a torque rated 0.53 nm speed rated 327 rpm current rated 1.5 a stall torque 2.15 nm http://www.sainsmart.com/products/3-axis-desktop-robotic-arm http://www.sainsmart.com/products/3-axis-desktop-robotic-arm https://www.arduino.cc/ kamran shahani (et al.), design and control of unmanned ground vehicle for search and rescue missions (pp. 66 71) sukkur iba journal of emerging technologies sjet | volume 1 no. 1 january – june 2018 © sukkur iba university 69 2.5. xbee pro s1 module this is a very interesting wireless device used for wireless communication between two points through buildings or any place. there are many xbee modules such as xbee s1 and xbee s2, we are using xbee pro s1 this is the advanced version of the remaining xbee modules. figure 5 shows the front view of xbee pro s1. this device is the product of digi tech [11]. it has a built-in antenna which makes the better communication, increase the distance of communication. these modules allow a very reliable and simple communication between microcontrollers, computers, systems, really anything with a serial port! point to point and multi-point networks are supported with a range of 1500 meter coverage. the xbee pro s1 module in this vehicle is used to provide the wireless communication between the unmanned ground vehicle and the surface controller. fig. 5. xbee pro module. source. https://www.digi.com 2.6. xbee x-ctu x-ctu is software used to configure a connection between pc and xbee module. first we have to make the connection between pc and device. after this we select com port where xbee is connected with the laptop port. after this we have to select correct baud rate which you set in the arduino, matching of baud rate is very important if there is no matching wireless system can’t work. figure 6 shows the interfacing window of the x-ctu. from this software xbee input and output ports are initialized. after declaring of the ports proper selecting of sample rate is important in our case 20 is set. fig. 6. xbee x-ctu. source. https://www.digi.com 3. controlling the robot movement a controller is made for the controlling of ugv movements and manipulation of arm and camera, in which different switches and knobs are used. when user from the controller send the command through buttons or knobs, signal will be generated in the xbee and xbee sends the signal to the controller where signal is processing, then these signals transmitted to the ugv to perform the desired tasks. figure 7 shows the controller of the robot. , table 1 show the input commands which sense the robot for specific movement and table 2 shows the main specifications of the ugv. https://www.digi.com/ https://www.digi.com/ kamran shahani (et al.), design and control of unmanned ground vehicle for search and rescue missions (pp. 66 71) sukkur iba journal of emerging technologies sjet | volume 1 no. 1 january – june 2018 © sukkur iba university 70 fig. 7. main controller of the robot. table ii. robot commands. table iii. ugv specifications. 4. results the execution of the unmanned ground vehicle (ugv) for search and rescue mission hardware model experimented throughout the real-time experiment. figure 8 shows the experimental results of the unmanned ground vehicle with no load and full load torque, current and speed. it was affirmed that the model was flawlessly towing on both glossy and irregular surfaces. the dynamic strength of the crawling vehicle while transporting the objects was kept. the vehicle can operate remotely via xbee from up to the boundary of 1000 meters coverage. the manipulator is proficient of grasping objects up to 1000 meters radius with live video feedback. the battery can serve for 8 hours outwardly renewing. figure 9 shows the main model of the ugv. fig. 8. ugv load and no load results. these figures are formulated in matlab version r2014b. figure 8 shows the no load and full load speed, current, and torque of the unmanned ground vehicle on the ground. therefore from figure we can see that slope of torque vs current is 13.114754. the reciprocal is 0.076250. maximum output mechanical power is 18.450975(watts). this happens at the 0 50 100 150 200 250 300 350 400 0 200 400 torque vs. speed & torque vs. current torque (oz-in) s p e e d r p m 0 50 100 150 200 250 300 350 400 0 5000 10000 c u r r e n t m a 0 50 100 150 200 250 300 350 400 0 5 10 15 20 torque (oz-in) o u t p u t p o w e r w a t t s torque vs. output power & torque vs. input power 0 50 100 150 200 250 300 350 400 0 20 40 60 80 i n p u t p o w e r w a t t s 0 50 100 150 200 250 300 350 0 0.1 0.2 0.3 0.4 0.5 torque (oz-in) p o w e r e f f i c i e n c y n o u n i t input character command f move forward b move backward l turn left r turn right k1-gripper open or close k2shoulder lower or upper k3wrist twist clock wise or anti clockwise specification explanation ugv size ( l x w x h) 170 x 167 x 80 mm crawler treads (width) 50 mm manipulator arm 200 mm controlling range 1000 meter (open area) weight 2 kg kamran shahani (et al.), design and control of unmanned ground vehicle for search and rescue missions (pp. 66 71) sukkur iba journal of emerging technologies sjet | volume 1 no. 1 january – june 2018 © sukkur iba university 71 torque load of 152.5 (oz-in), with current 3500 (ma). fig. 9. main model of the robot. 5. conslusion this article confers a scientific overview of the implementation of an unmanned ground vehicle with the three degree of freedom (3dof) manipulator arm for search and rescue missions. a model was created for an apparent induction of the method and it has been decided that by this sort of system invented, search and rescue operations can be done with less human through appearance while rescuing, through keeping the human from dangers. the design method advised in this article is cost-effectively applying a fullduplex transmission and suitable for military search and monitoring missions. references [1] j. pyo,“future unmanned system design for reliable military operations,” international journal of control and automation. korea, vol. 5, pp. 173-186, september 2012. [2] a. bouhraoua, n. merah, m. aldajani and m. elshafei, “ desing and implementation of an unmanned geound vehicle fo security applications”, proceedings of the 7th international symposium on mechatronics and its applications. saudi arabia, vol. 4, pp. 20-22, april 2010. [3] d. voth, "a new generation of military robots", ieee intelligent systems. usa, vol. 19, pp. 2-3, jul-aug 2004. [4] s. tsugaw, “vision-based vehicles in japan: machine vision system and driving control systems”, ieee transactions on industrial electronics. vol. 41, pp. 398405, 1994. [5] a. bugaje, a. loko, a. ismail, a. samuel, “the unmanned ground vehicle for fumigation purpose”. international journal of engineering trends and technology. nigeria, vol 30, december 2015. [6] s. singh and p. ranjan, “towards a new low cost, simple implementation using embedded system wireless networking for uavs”, proceedings of the ieee 5th international conference on advanced networks and telecommunication systems. india, pp. 18-21, december 2011. [7] t.gillespie,“fundamentals of vehicle dynamics” sae interational, 1992. [8] y.ali, s. noor, and s. bashi, “microncontroller performance for dc motor speed control system”, proceedings of power engineering conference.malaysia, december 2003. [9] a. mohebbi, s. safaee, m. keshmiri and s. mohebbi, “design, simulation and manufacturing of a tracked surveillance unmanned ground vehicle”, proceedings of the ieee international conference on robotics and biomimetices. china, december 2010. [10] b. binoy, t. keerthana, p. barani, s.aswathy, “ a gsm based versatile unmanned ground vehicle”, proceedings of international conference on emerging trends in robotics and communication technologies. india, december 2010. [11] d. vidhya, n. mapari, “ wireless control and transmission of data for underwater robot”, international journal for innovative research in science and technology. india, vol. 2, pp. 364-369, may 2016. format template vol. 3, no. 1 | january june 2020 sjet | issn: 2616-7069 | vol. 3 | no. 1 | © 2020 sukkur iba university 16 facile synthesis and characterization of mesoporous titanium oxide nanoparticles for ethanol sensing properties altaf hussain shar1, muhammad nazim lakhan1, jingyuan liu1, mukhtiar ahmed1, muhammad basit chandio2, ahmer hussain shah3, abdul hanan1, irfan ali4, jun wang1 abstract: mesoporous tio2 nanoparticles were successfully synthesized via solvothermal. the morphology and crystal structure was characterized by uv–vis spectrum (uv-vis), fourier transform infrared (ftir) spectroscopy, x-ray diffraction (xrd), scanning electron microscopy (sem) and transmission electron microscopy (tem). all the observations confirmed that the as-fabricated mesoporous tio2 nanoparticles were successfully synthesized with surface plasmon resonance peak between a range of 250-350 nm and its pattern meets with the jcpds standard (card no. 21-1272). tem confirmed the mesoporous structure morphology and shows the incredible gas sensing performance due to their large accessible surface area. furthermore, the as-prepared tio2 nanoparticles exhibited more rapid response/recovery and higher sensitivity towards ethanol at 180°c distinguished with isopropyl alcohol and methanol. in addition, it can be affirmed that the synthesized mesoporous tio2 nanoparticles are a promising applicant for fabricating high-performance ethanol gas sensor in real-time monitoring. keywords: gas sensor; mesoporous; nanotechnology; tio2; ethanol sensing. 1. introduction currently, atmospheric environmental protection is considered as a concerning issue because of the emission of harmful gas molecules and due to the rapid development in modern industries. to mitigate this, the 1key laboratory of superlight material and surface technology, ministry of education, harbin engineering university, pr people’s republic of china. 2college of mechanical and electrical engineering, harbin engineering university, people’s republic of china 3department of textile engineering, balochistan university of information technology, engineering and management sciences, quetta, pakistan 4college of chemical engineering, beijing university of chemical technology, people’s republic of china corresponding author: altafshar12@gmail.com detection of toxic gases is extremely essential for the excellence of the environment and human health [1]. vapor sensors based on ethanol are widely usable sensors owing to their unique properties in chemical and biomedical industries and also for the analysis of breath [2]. high sensitivity, minimum altaf hussain shar(et al). facile synthesis and characterization of mesoporous titanium oxide nanoparticles for ethanol sensing properties (pp. 16 22) sjet | issn: 2616-7069 | vol. 3 | no. 1 | © 2020 sukkur iba university 17 operating temperature, and less recovery time with short responses are ideal features in ethanol vapor (ev) sensors. therefore, ev sensors and their functional materials research attracted huge attention by scientists for the development of high-performance ev sensors. nowadays, many sensing mechanisms and technologies have been employed for volatile organic compounds (vocs) detection including thermal conductivity, catalyst, electrochemical, chemi-resistors types, mechanical and optical [3]. among them, chemi-resistors based sensors are mostly preferable and economical devices with the existence of transuding platforms and acceptor materials and are broadly accepted because of their high potential application and long-term stability [4]. the gas sensing material is considered an important parameter for the selection of gas sensors. among many, metal oxide semiconductors (moss) nanomaterials have attained some significant attention and considered promising material due to advantages such as; easy fabrication, fast response and recovery time, low operating cost, minimum power consumption, and minimum size with excellent chemical stability [5]. mesoporous semiconducting metal oxides have been extensively used as the chemi-resistive based gas sensors due to their outstanding properties such as high surface area, large pores volume, high interconnection, long-term stability, high electron conductivity and enhanced sensing performance [6]. among other metal oxides, titanium dioxide (tio2) with wide-bandgap (3.4 ev) moss are considered as promising material because of its distinctive properties includes chemical stability, excellent sensor performance, low cost, high activity, nontoxicity and abundance [7], and is used in various applications including batteries [8], photocatalysis, water splitting, solar cells, gas sensors, and biological application [9]. tio2 attracts much attention in the field of gas sensors [10]. in comparison with some common moss gas sensors operated on high temperatures, tio2 is favorable owing to higher sensitivity, fast response, long-term stability, and easily detectable gas at low temperatures. various structures of tio2 used for ethanol detection have been reported, such as nanoparticles and nanoflowers [11, 12]. however, pristine tio2 is not widely investigated due to they are some drawbacks including low sensitivity, slow responserecovery time and limited specific area [13]. to solve these problems, many researchers committed to enhance the performance of tio2 based sensors to modify morphology of tio2 surface and nanostructure, as they are key factors that influence gas sensing performance [14]. particularly, mesoporous tio2 nanostructures have a large specific surface area which provides numerous active sites facilitating more oxygen to be adsorbed at the surface and it also allows gas molecules to easily penetrate and adsorb on the surface of sensing materials for the improvement of response recovery time and detection limit [15]. much research has still to be made for the development of mesoporous sensing materials having properties such as high sensitivity, minimum operating temperature, short response with less recovery time, easy fabrication and environmental flexibility. herein, a novel ethanol vapor based sensor on mesoporous tio2 nanoparticles has been successfully synthesized via solvothermal methods. the as-fabricated mesoporous tio2 material microstructure properties were characterized by ftir, uv-vis, xrd, sem and tem. furthermore, gas sensing properties such as operating temperature, response to concentration, selectivity, response and recovery time were evaluated. altaf hussain shar(et al). facile synthesis and characterization of mesoporous titanium oxide nanoparticles for ethanol sensing properties (pp. 16 22) sjet | issn: 2616-7069 | vol. 3 | no. 1 | © 2020 sukkur iba university 18 2. materials and method 2.1. synthesis mesoporous tio2 nanoparticles: all the chemicals we used in this experiment are of analytical grade and used directly without any further purification prior to usage. mesoporous tio2 nanoparticles are prepared by an environmentally friendly and one-step solvothermal route. in a typical process, first 20 ml of deionized water (dw) and 40ml isopropyl alcohol were mixed together using magnetic stirrer until a homogeneous solution formed. then, 6.0 g of titanium sulfate (ti (so4)2) was added under strong stirring till a uniform solution achieved. afterward, the aqueous solution was transferred into 100 ml teflon-lined stainless steel autoclave and heated at 90˚c for 12 h. later, as-prepared tio2 were centrifuged, rinsed and overnight dried at 90˚c. finally, the dried powder was calcined in tube furnace at 300°c for 2 h in atmospheric air at a rate of 5 °c/min. 2.2. characterization uv-vis absorption spectra were calculated by using a tu-1901 dual-beam uv-vis spectrophotometer. the ftir spectrum of mesoporous nanoparticles was collected on kbr plates cast using a perkin elmer spectrum 100 ftir spectrometer. the crystal structure was investigated by xrd system with cu k1 radiation (= 0.15406 nm). the surface morphology of catalyst was observed with sem (joel jsm – 6480a) operated at a 20kv of driving voltage while tem images were acquired by using an fei tecnni g2 instrument. the gas sensing measurements were tested by a commercial nmdog multi-functional accuracy sensor analysis tester (manufactured in changsha city, china) at room temperature. 2.3. fabrication and measurement of the sensor in a typical process, the as-prepared sensing material was fully grinded by adding a small amount of ethanol to form slurry, and then pasted it onto the ceramic tube and then heated at 60°c for 2 h to evaporate the ethanol and kept in air for one day to improve the stability of the sensing materials layer. the operating temperature was controlled by providing the heating current through the nicr, resistor heating wire inserted into the ceramic tube. sensing properties of the gas sensor were measured by a commercial nmdog multifunctional precision sensor analysis instrument (changsha dingchen scientific instrument co, ltd, hunan, china). for measurement, the saturated target vapor in corresponding amounts was injected into a closed 10 l chamber by a micro-syringe to obtain the different concentrations of analytes. after fully mixed with atmospheric air, the sensor was put into the chamber to measure its performance. when the response on the display reached constant value, the sensor was taken out to atmospheric air. the response of the sensor is defined as the s=rg/ra, where rg is the resistance of the sensor in target gas and ra is the resistance of the sensor in air. the response/ recovery time is defined as time spent by the sensor to achieve 90% of the total resistance change. 3. results and discussion 3.1. uv-visible spectrum the uv-vis absorption spectrum of mesoporous tio2 nanoparticles is shown in fig. 1. uv-vis spectrum of tio2 sharp edge 250-350 nm showing mesoporous tio2 nanoparticles absorbs light from the ultraviolet region at room temperature displaying a good absorption band in the uv region [16]. altaf hussain shar(et al). facile synthesis and characterization of mesoporous titanium oxide nanoparticles for ethanol sensing properties (pp. 16 22) sjet | issn: 2616-7069 | vol. 3 | no. 1 | © 2020 sukkur iba university 19 fig 1. the uv-visible spectrum of mesoporous titanium dioxide nanoparticles. 3.2. ftir analysis ftir spectroscopy was used to characterize the proper surface functional groups responsible for the synthesis of mesoporous tio2 nanoparticles as shown in fig. 2. the intensive absorption peaks were characterized by a number of characteristic bands occurring at 3744 cm-1, 3648 cm-1, 2917 cm-1, 2853 cm-1, 1741 cm-1, 1585 cm-1, 1376 cm-1 and 1118 cm-1. the characteristic peaks were noticed between 3700 cm-1 and 3500 cm1 were related to tio2 product as well as small intensity peak at 1650 cm-1 was showing stretching and bending vibrations of hydroxyl groups on the surface of tio2 nanoparticles. additionally, another absorption peaks situated at 2917 and 2853 cm-1 were assigned to the asymmetric and symmetric stretch vibrations of ch2 groups, 1740 cm -1 represents the stretching of c=o aldehydes group, 1586 cm-1 (c-c) stretches in the aromatic ring, 1420 cm-1 (ch groups) and 1118 cm-1 (c=o stretching vibrations). the obtained peaks in spectra confirm the formation of final tio2 products [17]. 3.3. xrd analysis xrd pattern confirms the composition and crystal structure of as-synthesized tio2 nanoparticles. materials were characterized in a range of 10-90. fig. 3 depicted the xrd patterns of the obtained anatase tio2 sample. all the diffraction peaks located at 2θ = 25.2, 37.8, 48.0, 53.9, 55.0, 62.7, 68.7, 70.3 and 75.0 could be indexed to (101), (004), (200), (105), (211), (204), (116), (220) and (215) planes of anatasetio2, respectively. the peaks of the anatase tio2 phase are of (jcpds card no. 21-1272) standard. no characteristic peaks of impurity phases were observed in the xrd pattern and sharp diffraction peaks indicated good crystallinity. the grain size of mesoporous tio2 nanoparticles was calculated using the scherrer formula [18]. d= (kλ/ (βcosθ) where d is average crystallite size, λ is the wavelength of cu kα (0.154 nm), k is a shape factor which is 0.9, β is measured from the full width at half maximum (fwhm) in radian and θ is bragg angle it is obtained by dividing 2 the 2θ value of corresponding diffraction peak. the mean crystallite sizes of mesoporous tio2 nanoparticles were found in the ranges of 17-24 nm as shown in table 1. fig 2. ftir analysis of mesoporous tio2 nanoparticles. table 1. particle size calculation from the xrd pattern. lattice plane peak position (degree) fwhm (degree) particle size (nm) (101) 25.2 0.47 17.3 (004) 37.8 0.57 17.8 (200) 48.0 0.40 18.4 (211) 55.0 0.37 19.0 (215) 75.0 0.20 48.5 altaf hussain shar(et al). facile synthesis and characterization of mesoporous titanium oxide nanoparticles for ethanol sensing properties (pp. 16 22) sjet | issn: 2616-7069 | vol. 3 | no. 1 | © 2020 sukkur iba university 20 fig 3. xrd patterns of mesoporous tio2 nanoparticles fig 4. (a-b) sem images of mesoporous tio2 nanoparticles and tem (c-d). 3.4. morphology and structure analysis the morphology of the as-synthesized mesoporous tio2 nanoparticles sample was investigated by sem. fig. 4a depicted that asobtained mesoporous tio2 nanoparticles were adhered to by many small size mesoporous particles that are densely distributed inside and outside of the substrate surface. fig. 4b showed that the fine nanoparticles are assembled on the mesoporous surface of tio2 pores were agglomerated to form large particles (lumps) and the shape of nanoparticles is irregular with their average sizes range around 20-200 nm. the microstructure of mesoporous tio2 nanoparticles was further investigated by the tem technique. fig. 4c revealed that the higher degree of mesoporous structure and also large number of pores appeared on the surface of the as-prepared mesoporous tio2 nanoparticles. fig. 4d showed the hrtem images of mesoporous tio2 nanoparticles from there we could be observed that the shape of particles is irregular and their average size ranges 20-70 nm. tem results are correlated with sem results. 3.5. gas sensing properties the porous structure plays a vital role in determining the sensing properties by affecting the diffusion of test gases toward sensing material surface [19]. the operating temperature of the sensor is significantly influenced by moss based sensors. therefore, the gas sensing performance of the mesoporous tio2 nanoparticles to 100 ppm ethanol gas was examined. fig. 5a revealed the response of the sensor toward 100 ppm ethanol at an operating temperature from 100°c to 220°c. it is found that the response increased with the initial operating temperature, and reached the maximum value at about 180 °c, afterward the response decreased with further increment in temperature then the existence of an optimal temperature was observed, which is finally taken as 180°c with the strongest response value of the sensor based on tio2 is 5.2 at 180 °c. the selectivity is a crucial parameter for the gas sensor to evaluate the sensing performances of gas sensors for their practical application. thus, the selectivity test of the sensor was investigated by exposing several kinds of common gases including ethanol, isopropyl alcohol, and methanol tested with a concentration of 100 ppm at the same temperature of 180 °c and the results are shown in a bar graph as shown in fig. 5b. clearly, it can be observed that the sensorbased mesoporous tio2 nanoparticles exhibited a much higher response to ethanol in comparison to any other gases at the same concentration. the response and recovery time also plays a significant role in the altaf hussain shar(et al). facile synthesis and characterization of mesoporous titanium oxide nanoparticles for ethanol sensing properties (pp. 16 22) sjet | issn: 2616-7069 | vol. 3 | no. 1 | © 2020 sukkur iba university 21 practical detection of detrimental gases. fig. 6 showed a dynamic curve of mesoporous tio2 nanoparticles response and recovery towards 100 ppm ethanol gas at 180°c was plotted. the result affirms that the resistance of the sensor instantly changes when the sensor was exposed to targeted gases, and later reached a steady state. the response and recovery time of the sensor to ethanol was within 25 s and the recovery time was 15 s, respectively. fig 5. (a) response of the different mesoporous tio2nanoparticles versus operating temperature to 100 ppm acetone (b) selectivity of mesoporous tio2 nanoparticles towards 100 ppm of various gases. fig 6. the response-recovery dynamic curve of mesoporous tio2 nanoparticles to 100 ppm ethanol at 180°c. 4. conclusion we have successfully prepared mesoporous tio2 nanoparticles by a simple and low cost solvo thermal method under the calcinations temperature at 300°c. the asobtained sample was characterized by various analytic techniques and their gas sensing properties were examined. it is found that the mesoporous structure of tio2 nanoparticles exhibits high surface area and large pore volume and showed a better performance of ethanol sensing towards 100 ppm at 180°c with fast response and recovery times. the enhancements of gas sensing properties were ascribed to the distinctive porous structure. acknowledgment the author thanks the financial support of the national natural science foundation of china (nsfc 51402065 and 51603053), natural science foundation of heilongjiang province (b2015021), fundamental research funds of the central university, the application technology research and development projects of harbin (2015raqxj038) and defense industrial technology development program (jcky2016604c006). references [1]. n. t.a.thu, n.d. cuong, l.c. nguyen, d.q. khieu, p.c. nam, n.v. toan, c.m. hung, n.v. hieu, fe2o3 nanoporous network fabricated from fe3o4/reduced graphene oxide for high-performance ethanol gas sensor, sensors and actuators b: chemical, vol. 255, 2018, pp. 3275-3283. [2]. d.r. miller, s.a. akbar, p.a. morris, nanoscale metal oxide-based heterojunctions for gas sensing: a review, sensors, and actuators b: chemical, vol, 204, 2014, pp. 250-272. [3]. t. yuan, z. li, w. zhang, z. xue, x. wang, z. ma, y. fan, j. xu, y. wu, highly sensitive ethanol gas sensor based on ultrathin nanosheets assembled altaf hussain shar(et al). facile synthesis and characterization of mesoporous titanium oxide nanoparticles for ethanol sensing properties (pp. 16 22) sjet | issn: 2616-7069 | vol. 3 | no. 1 | © 2020 sukkur iba university 22 bi2wo6 with composite phase, science bulletin, vol. 64, 2019, pp. 595-602. [4]. m. tonezzer, l.t.t. dang, h.q. tran, s. iannotta, multiselective visual gas sensor using nickel oxide nanowires as chemiresistor, sensors, and actuators b: chemical, vol. 255, 2018. [5]. a. dey, semiconductor metal oxide gas sensors: a review, materials science and engineering: b, vol. 229, 2018, pp. 206217. [6]. n.d. hoa, s.a. el-safty, highly sensitive and selective volatile organic compound gas sensors based on mesoporous nanocomposite monoliths, analytical methods, vol. 3, 2011, pp. 1948–1956. [7]. r. wilson, c. simion, c. blackman, c. carmalt, a. stanoiu, f. di maggio, j. covington, the effect of film thickness on the gas sensing properties of ultrathin tio2 films deposited by atomic layer deposition, sensors, vol. 18, 2018, pp. 735. [8]. m.v. reddy, g.v. subba rao, b.v.r. chowdari, metal oxides and oxysalts as anode materials for li ion batteries, chemical reviews, vol. 113, 2013. [9]. a. bertuna, e. comini, n. poli, d. zappa, g. sberveglieri, titanium dioxide nanostructures chemical sensor, procedia engineering, vol. 168, 2016, pp. 313-316. [10]. c. wang, y. li, p. qiu, l. duan, w. bi, y. chen, d. guo, y. liu, w. luo, y. deng, controllable synthesis of highly crystallized mesoporous tio2/wo3 heterojunctions for acetone gas sensing, chinese chemical letters, (2019). [11]. s. nasirian, h. milani moghaddam, hydrogen gas sensing based on polyaniline/anatase titania nanocomposite, international journal of hydrogen energy, vol. 39, 2014, pp. 630-642. [12]. a. h. shar, m. n. lakhan, j. wang, m. ahmed, k. t. alali, r. ahmed, i. ali, a. q. dayo, facile synthesis and characterization of selenium nanoparticles by the hydrothermal approach, digest journal of nanomaterials and biostructures, vol. 14, 2019, pp. 867-872. [13]. j. zhang, x. liu, g. neri, n. pinna, nanostructured materials for roomtemperature gas sensors, advanced materials, vol. 28, 2016, pp. 795-831. [14]. s. zhang, p. song, z. yang, q. wang, facile hydrothermal synthesis of mesoporous in 2 o 3 nanoparticles with superior formaldehyde-sensing properties, physica e: low-dimensional systems and nanostructures, vol. 97, 2018, pp. 38-44. [15]. s. liu, z. wang, h. zhao, t. fei, t. zhang, ordered mesoporous co3o4 for high-performance toluene sensing, sensors and actuators b: chemical, vol. 197, 2014, pp. 342-349. [16]. b. durairaj, t. xavier, s. muthu, fungal generated titanium dioxide nanopartilces for uv protective and bacterial resistant fabrication, international journal of engineering science and technology (ijest), vol. 6, 2014, pp. 621-625. [17]. g. rajakumar, a. a. rahuman, s. m. roopan, v. g. khanna, g. elango, c. kamaraj, a. a. zahir, k. velayutham, fungus-mediated biosynthesis and characterization of tio(2) nanoparticles and their activity against pathogenic bacteria, spectrochim acta a mol biomol spectrosc, vol. 91, 2012, [18]. f. t. l. muniz, m. a. r. miranda, c. m. d. santos, j. m. sasaki, the scherrer equation and the dynamical theory of xray diffraction, vol. 72, 2016, pp. 1-6. [19]. z. wen, l. zhu, y. li, z. zhang, z. ye, mesoporous co3o4 nanoneedle arrays for high-performance gas sensor, sensors and actuators b: chemical, vol. 203, 2014, pp. 873-879. format template vol. 3, no. 1 | january june 2020 sjet | issn: 2616-7069 | vol. 3 | no. 1 | © 2020 sukkur iba university 44` an erp based blood donation management system for hospital and donor ghulam muhammad1, hamza asif1, farrukh abbas1, imran memon1, hadiqua fazal1 abstract: the objective of this paper is to develop a mobile blood donation management system application. this paper an android based application development technique by using an erp model database management system. the techniques involve using mobile development ides and adequate apis to have desired functionalities. there are two main mobile developing platforms present in the world ios and android. we have developed our application on android os. different applications were surveyed and used to explore the presently available features to the end-user. after trials and research, the outline was made to what extent should go and developed. as the system is developed for hospitals and donors, the hospital puts a request for blood groups on the application. the system then finds nearby users online with the requested blood groups, if anybody required for his / her relative he or she can use this application for find donors who are available or offline with full information of donor if donor or user is interested in donation then he has done to the requester. users’ locations are tracked in real-time. if the users proceed to the hospital, the tracking shows if they are coming or not. keywords: android gui, erp model, hospital model, donor model 1. introduction: nowadays, health technologies are developing rapidly. incurable diseases are cured with the latest technology and medical research. with the rapidly developing technologies, medical professionals must cope up with changing trends and technologies. these technologies require fast response from professionals [1,2,3,4]. such technology is a blood donation management system. a system that is capable of catering multiple users at a time. hospital operations which include surgeries, transplantations, and medical processes, require a blood supply to facilitate patients undergoing those processes [5,6,7,8]. a 1 department of computer science, bahria university karachi, pakistan corresponding author: ghulammuhammad.bukc@bahria.edu.pk blood donation management system can manage information of users, track their arrival to hospitals, informs about users online on the system with the registration of authentic user cell number and hospital related information based on google map location [9,10,11]. 2. problem statement blood arrangements are uncertain. people who committed to donate often change their plan to donate. as a result of the survey done, we found that conventional apps just register users and donors [12,13,14]. the user puts requests and donors reply to those requests on the application. it is then not guaranteed mailto:ghulammuhammad.bukc@bahria.edu.pk ghulam muhammad (et al.), an erp based blood donation management system for hospital and donor (pp.44-54) sjet | issn: 2616-7069 | vol. 3 | no. 1 | © 2020 sukkur iba university 45 whether the commitment done between the user and donor is fulfilled or not. on further analysis it was found that this posed some of the problems which were the following: 1) either the user is authentic or not. is he/she really having the need for blood? 2) criminals can misuse the application. invite people to donate and then loot them. 3) donors show their will to donate on the application but do not proceed for donation hence wasting the time of users. 3. related work we surveyed 8 mobile blood donation management applications that are currently being used. all the applications have most of the features in common mentioned below. we will discuss some of them in this section these features include user registration through sms verification, user profile, profile related services, real-time tracking, user personal information, limitation factor, availability countrywide, availability internationally, and location provision [15,16,17,18]. table 1 shows the comparison of present applications that we surveyed. this provides a bird's eye view on application features. indicating what they are capable of and whatnot. as we can see the comparison in the below table, there is no application with all features. our aim and objective are to not only cover these deficiencies but to develop with more features. after the survey and research, the architecture of two side applications was selected. the hospital will have its own application while donors will have their own application. this is discussed separately in the subsections below. 3.1. user side app (hospital) applications first module, which is the main module, is the user's (hospitals) side application. hospitals will use the app so that the donors have trust and they know they are in safe hands. any person in need of blood will contact the hospital. the hospital will generate requests on the app [19]. the app will find online donors first. if there are no online users, then it will no offline donors [20] table 1. comparison of applications ghulam muhammad (et al.), an erp based blood donation management system for hospital and donor (pp.44-54) sjet | issn: 2616-7069 | vol. 3 | no. 1 | © 2020 sukkur iba university 46 3.2. donor side application the donor side application will allow registering donors. put their personal information in their accounts. they will be tracked in real-time if they are proceeding to donate or not so that hospital can arrange alternatives. 4. methodology the design and methodology section cover system architecture use case diagram and uml diagram. the system architecture comprises of the main architecture in which we have a user application to which other entities are sending and receiving data. it features a firebase cloud messaging, a firebase database, and asp.net web services [21,22]. next, a use case diagram shows how actually the architecture is working between the donors and the hospital. it shows both online and offline case. please refer to fig. 1 for further understanding. fig. 1: system design the fig. 2 use case diagram explains the workflow of donors and hospitals. at the donor end, the request is received. the donor can accept or reject the request. on the hospital end, searching for a donor is being done on two occasions. one is when the donor is online. if the donor is online, the request is generated. if the donor is offline, an sms broadcast is done. fig 2: use case diagram finally, we have the system uml diagram fig. 3 which shows the data flow between the classes and entities of the application. fig. 4 shows donors and their history data flow and fig. 5 shows the requested functionality that how to request sent from hospital to donor, in this application hospitals register themselves to help patients by providing them donor successfully and save their lives. many donors donate their blood without any required money they will arrive or reach at hospitals donate blood either match or unmatched group, then hospital blood bank provides blood to patients instead of an unmatched group. by using this application donor are free from any fraud or misuse of blood, the hospital is responsible to manage this type of activity to handle and control. ghulam muhammad (et al.), an erp based blood donation management system for hospital and donor (pp.44-54) sjet | issn: 2616-7069 | vol. 3 | no. 1 | © 2020 sukkur iba university 47 fig 3: uml diagram fig 4: donors data fig 5: request functionality in fig. 6 represent the graphical user interface of the hospital where hospital management or hospital blood bank control this application and this application could be registered by multiple hospitals because patients are everywhere and the donor could reach over there in case of emergency, in this regard employee of the hospital do connect patients and donor via this application where patients could get benefit from it. fig. 7 about the user interface of the patient where the patient himself or his/her relative or friend can register after registration a unique id will be generated for the user which will be sent to the donor when request sent from patient/user, in this portal patient must link with the concerned hospital where he/she is admitted because in this application donor will reach a destination which is the hospital, fig. 8 define the blood group matching mechanism where donor always confusing about matching that his/her donation goes to ghulam muhammad (et al.), an erp based blood donation management system for hospital and donor (pp.44-54) sjet | issn: 2616-7069 | vol. 3 | no. 1 | © 2020 sukkur iba university 48 the right patient or submitted in blood bank instead of unmatched blood group, sometimes patient relative don’t know that which blood group is required in case of o+ and oblood group, because these types of blood group are very less in humans and very difficult to get it from friends or family, so in critical conditions, it will help in this blood group matching that who can provide either same or cross blood or replaced from the blood bank. when the donor agreed and accept request from the sender then it can be located that how much far from the hospital, in fig. 9 focus on donors’ availability that how many donors are available nearly or far from the hospital. if a donor is not available, then we had done another solution that it could be found through offline request where the user inputs his cell number but forget to on mobile data or may not available online then send a message through his cell number when he will online then check his status on google map fig. 10 that where is he either he will be reach at a hospital within time or not or decline him and find another donor. fig.11 shows the request portal which is sent by the patient or from hospital blood bank reception to the donor. in fig.12, the complete message sent to the donor where the amount shows that you have requested for the amount and complete data of a patient with hospital name is there, at the end we design a blood bank user interface portal which is in fig. 13. if the patient relative or any friend is not available, the hospital is responsible for this patient, in this case the blood bank send request to donors for donate blood and pay for it. as surveyed in many hospitals we get that many blood banks done earlier if patient is in critical condition after successfully patient is recovered then add amount in patient bills. fig. 6. the graphical user interface of blood bank of hospital fig 7. the graphical user interface of patient ghulam muhammad (et al.), an erp based blood donation management system for hospital and donor (pp.44-54) sjet | issn: 2616-7069 | vol. 3 | no. 1 | © 2020 sukkur iba university 49 fig 8. blood group matching fig 9. availability of donors fig 10. location of donor fig 11. request portal ghulam muhammad (et al.), an erp based blood donation management system for hospital and donor (pp.44-54) sjet | issn: 2616-7069 | vol. 3 | no. 1 | © 2020 sukkur iba university 50 fig 12. message sent to the donor fig 13. blood bank user interface 5. implementation the implementation of the features is covered in this section of the report. the distinctive features include notification sms broadcasting, firebase cloud messaging, google maps for hospital and donor, donor history, dismissal of request, request generation by hospital, user account verification by sms code. the code sections are written here for an understanding of the functionality of the application. 5.1. notification sms broadcasting [httppost] public async task<string> sendsms(smsmodel sms) { var data = new historydetails(); string abc = string.empty var sid = "ac08036fa1e7d2e8fdf63e2ad27cd35613"; var token = "aa68be533a2b6cd8b39da25ada9057b5"; twilioclient.init(sid, token); string addess = string.empty; var firebase1 = new firebaseclient("https://bloodbankfd858.firebaseio.com/hospital/"); var data1 = await firebase1.child(sms.info.hospitalid).oncesingle async<hospital>(); requestinfo req = sms.info; var firebase2 = new firebaseclient("https://bloodbankfd858.firebaseio.com/"); var postinfo = await firebase2.child("history").postasync(sms.info); string key = postinfo.key; var firebase3 = new firebaseclient("https://bloodbankfd858.firebaseio.com/hospital/" + sms.info.hospitalid + "/history"); await firebase3.child(key).putasync("true"); foreach (var i in sms.donerssms) { abc = sms.info.no_of_bottels; var to = new phonenumber(i.doners.phonenumber); var from = new phonenumber("+16182241163"); var message = messageresource.create( to: to, ghulam muhammad (et al.), an erp based blood donation management system for hospital and donor (pp.44-54) sjet | issn: 2616-7069 | vol. 3 | no. 1 | © 2020 sukkur iba university 51 from: from, body: "dear doner,you are requested to please proceed to the blood bank of \n" + "hospital name :" +data1.hospitalname+ "\n" + "address : "+data1.address+"\n" + "following are the details :\n" + "patient id :" + sms.info.patentid + "\n" + "patient name : " + sms.info.patentname + "\n" + "case : " + sms.info.case + "\n" + "required bloodgroup : " + sms.info.type + "\n" + "quantity :" + sms.info.no_of_bottels + "\n" + "for amount :" + sms.info.amount + "\n\n\n" + "thank you for your donation and kindness" ); var firebase5 = new firebaseclient("https://bloodbankfd858.firebaseio.com/history/" + key); await firebase5.child(i.key).putasync(true); var firebase4 = new firebaseclient("https://bloodbankfd858.firebaseio.com/doners/" + i.key + "/history"); await firebase4.child(key).putasync(data); var firebase6 = new firebaseclient("https://bloodbankfd858.firebaseio.com/history/" + key + "/users/"); await firebase6.child(i.key).putasync(true); } return key; } 5.2. firebase cloud messaging [httppost] public async task<string> fcm(smsmodel sms) { var data1 = new list<string>(); foreach (var i in sms.donerssms) { data1.add(i.doners.token); } var firebase1 = new firebaseclient("https://bloodbankfd858.firebaseio.com/"); var postinfo = await firebase1.child("history").postasync(sms.info); string key = postinfo.key; var data = new fcmpayload { hospitalid = sms.info.hospitalid, historyid = key }; using (var sender = new sender("aaaa9w1uoga:apa91beow5yv9aj q8mzvnkikunewpiispxeulotjech2bkgqbzb hnboslvyxyl7e2_zufxyjasx5dczo007esuti pjipkv6olbu3da6dcbsxy4l3mzobnzp92ivn60 wtgpe48kaxb33s")) { var message = new message { registrationids = data1, data = data, notification = new notification { title = "request for blood", body = "blood requied" + sms.info.type, clickaction = "com.example.hamzaa.bloodbank.getinfo", sound = "type_notification" } }; var result = await sender.sendasync(message); string response = result.messageresponse.success.tostring(); if (response == "1") { var firebase2 = new firebaseclient("https://bloodbankfd858.firebaseio.com/hospital/" + sms.info.hospitalid + "/history"); await firebase2.child(key).putasync(true); var firebase3 = new firebaseclient("https://bloodbankfd858.firebaseio.com/hospital/" + sms.info.hospitalid + "/ongoingrequest"); await firebase3.child(key).putasync(true); } return key; } } public async task<string> fcmnear(string token,string name) using (var sender = new sender("aaaa9w1uoga:apa91beow5yv9aj ghulam muhammad (et al.), an erp based blood donation management system for hospital and donor (pp.44-54) sjet | issn: 2616-7069 | vol. 3 | no. 1 | © 2020 sukkur iba university 52 q8mzvnkikunewpiispxeulotjech2bkgqbzb hnboslvyxyl7e2_zufxyjasx5dczo007esuti pjipkv6olbu3da6dcbsxy4l3mzobnzp92ivn60 wtgpe48kaxb33s")) { var message = new message { registrationids = new list<string>{token}, notification = new notification { title = "reahced", body = "doner "+name+"reached", clickaction = "com.example.hamzaa.bloodbank.getinfo", sound = "type_notification" } }; var result = await sender.sendasync(message); string response = result.messageresponse.success.tostring(); return response; } } package com.example.hamzaa.bloodbank.fcm; import android.app.notificationmanager; import android.app.pendingintent; import android.content.context; import android.content.intent; import android.graphics.bitmapfactory; import android.media.ringtonemanager; import android.net.uri; import android.os.vibrator; import android.support.v4.app.notificationcompat; import android.util.log; import com.example.hamzaa.bloodbank.r; import com.example.hamzaa.bloodbank.navigationdraw er; import com.google.firebase.messaging.firebasemessagi ngservice; import com.google.firebase.messaging.remotemessage; import org.json.jsonexception; import org.json.jsonobject; /** * created by hamzaa on 11/25/2018. */ public class fcmmessageservice extends firebasemessagingservice { string type=""; @override public void onmessagereceived(remotemessage remotemessage) { super.onmessagereceived(remotemessage); type=remotemessage.getdata().tostring(); sendnotification(remotemessage.getnotification( ).getbody(),remotemessage.getnotification().get clickaction(),type); } private void sendnotification(string s,string action,string type) { string hospitalid="",historyid=""; if(type!=null) { try { jsonobject jsonobject = new jsonobject(type); hospitalid = jsonobject.getstring("hospitalid"); historyid = jsonobject.getstring("historyid"); } catch (exception e) { e.printstacktrace(); } } intent intent = new intent(action); if(hospitalid!=""&&historyid!="") { intent.putextra("hospitalid", hospitalid); intent.putextra("historyid", historyid); } intent.addflags(intent.flag_activity_clea r_top); pendingintent pendingintent=pendingintent.getactivities(this,0, new intent[]{intent},pendingintent.flag_one_sh ot); notificationcompat.builder builder=new notificationcompat.builder(this); builder.setcontenttitle(getstring(r.string.app_na me)); builder.setcontenttext(s); uri sounduri = ringtonemanager.getdefaulturi(ringtonemanag er.type_notification); ghulam muhammad (et al.), an erp based blood donation management system for hospital and donor (pp.44-54) sjet | issn: 2616-7069 | vol. 3 | no. 1 | © 2020 sukkur iba university 53 builder.setsound(sounduri); builder.setsmallicon(r.mipmap.ic_launcher); // bitmapfactory.decoderesource(this.getresource s(), r.drawable.logo); builder.setlargeicon(bitmapfactory.decodereso urce(this.getresources(),r.drawable.ic_launcher_ foreground)); builder.setautocancel(true); vibrator v=(vibrator)this.getsystemservice(context.vib rator_service); v.vibrate(1000); builder.setcontentintent(pendingintent); notificationmanager notificationmanager=(notificationmanager) getsystemservice(context.notification_se rvice); notificationmanager.notify(0,builder.build()); } } 6. results and discussions the android application developed is aimed to change the way how blood donation is done using the mobile application. this application is the solution to overcome all the difficulties faced by donors or needy people in regard to a mobile application. this will make it easy for collectors and donors since there is a certain level of trust developed by introducing some new and innovative features. this application serves a good purpose to both the hospitals and donors. hospitals can manage donors’ history, donors’ information, track their location in real-time, and generate requests in the form of notifications and sms. for donors, this application is a factor of authenticity. we have seen that donors certainly not trust needy individuals on the basis that they are strangers and they cannot be trusted. by introducing a hospital-end module donor can trust where they are going to donate and to whom. similarly, from the point of needy individuals, it provides a guarantee for them if the donors are approaching the hospital or not with the feature of real-time tracking. we also have included a finance factor by the hospital end which is a motivational factor for the donor to really approach to the needy individual references [1] oborne, d.j., bradley, s., and lloyd‐ griffiths, m., 1978. the anatomy of a volunteer blood donation system. transfusion, 18(4), pp.458-465. [2] wiwanitkit, v., 2000. a study on attitude towards blood donation among people in a rural district, thailand. age (years), 11(20), pp.21-30. [3] buciuniene, i., stonienë, l., blazeviciene, a., kazlauskaite, r., and skudiene, v., 2006. blood donors' motivation and attitude to nonremunerated blood donation in lithuania. bmc public health, 6(1), p.166. [4] shenga, n., pal, r., and sengupta, s., 2008. behavior disparities towards blood donation in sikkim, india. asian journal of transfusion science, 2(2), p.56. [5] oborne, d. j., s. bradley, and m. lloyd‐ griffiths. "the anatomy of a volunteer blood donation system." transfusion 18.4 (1978): 458-465. [6] şahinyazan, feyza güliz, bahar y. kara, and mehmet rüştü taner. "selective vehicle routing for a mobile blood donation system." european journal of operational research 245.1 (2015): 22-34. [7] buciuniene, ilona, et al. "blood donors' motivation and attitude to non-remunerated blood donation in lithuania." bmc public health 6.1 (2006): 166. [8] shenga, namgay, ranabir pal, and subhabrata sengupta. "behavior disparities towards blood donation in sikkim, india." asian journal of transfusion science 2.2 (2008): 56. [9] gillespie, theresa w., and christopher d. hillyer. "blood donors and factors impacting the blood donation decision." transfusion medicine reviews 16.2 (2002): 115-130. [10] mostafa, a.m., youssef, a.e. and alshorbagy, g., 2014. a framework for a smart social blood donation system based on mobile cloud computing. arxiv preprint arxiv:1412.7276. [11] marantidou, o., loukopoulou, l., zervou, e., martinis, g., egglezou, a., fountouli, p., dimoxenous, p., parara, m., gavalaki, m. and maniatis, a., 2007. factors that motivate and hinder blood donation in greece. transfusion medicine, 17(6), pp.443-450. ghulam muhammad (et al.), an erp based blood donation management system for hospital and donor (pp.44-54) sjet | issn: 2616-7069 | vol. 3 | no. 1 | © 2020 sukkur iba university 54 [12] baş, s., carello, g., lanzarone, e., ocak, z. and yalçındağ, s., 2016. management of blood donation system: literature review and research perspectives. in health care systems engineering for scientists and practitioners (pp. 121-132). springer, cham. [13] buyx, a.m., 2009. blood donation, payment, and non-cash incentives: classical questions drawing renewed interest. transfusion medicine and hemotherapy, 36(5), pp.329339. [14] alfouzan, n., 2014. knowledge, attitudes, and motivations towards blood donation among king abdulaziz medical city population. international journal of family medicine, 2014. [15] papagiannis, d., rachiotis, g., symvoulakis, e.k., anyfantakis, d., douvlataniotis, k., zilidis, c., markaki, a. and hadjichristodoulou, c., 2016. blood donation knowledge and attitudes among undergraduate health science students: a cross-sectional study. transfusion and apheresis science, 54(2), pp.303-308. [16] world health organization, 2012. blood donor selection: guidelines on assessing donor suitability for blood donation. world health organization. [17] ouhbi, s., fernández-alemán, j.l., toval, a., idri, a. and pozo, j.r., 2015. free blood donation mobile applications. journal of medical systems, 39(5), p.52. [18] balasenthilmurugan, l. and julian, a., 2015, march. design and implementation of automated blood bank using embedded systems. in 2015 international conference on innovations in information, embedded and communication systems (iciiecs) (pp. 16). ieee. [19] adsul, a.c., bhosale, v.k. and autee, r.m., 2018, january. automated blood bank system using raspberry pi. in 2018 2nd international conference on inventive systems and control (icisc) (pp. 252-255). ieee. [20] esmail, m.y. and osman, y.s.h., 2018, august. computerized central blood bank management system (ccbbms). in 2018 international conference on computer, control, electrical, and electronics engineering (iccceee) (pp. 1-5). ieee. [21] cheema, a.s., srivastava, s., srivastava, p.k. and murthy, b.k., 2015, december. a standard compliant blood bank management system with enforcing mechanism. in 2015 international conference on computing, communication and security (icccs) (pp. 1-7). ieee. [22] kumari, d.m.s. and wijayanayake, a.n., 2016, october. an efficient inventory model to reduce the wastage of blood in the national blood transfusion service. in 2016 manufacturing & industrial engineering symposium (mies) (pp. 1-4). ieee format template vol. 1, no. 1 | january june 2018 sjet | issn: 2616-7069 | vol. 1 | no. 1 | © 2018 sukkur iba 81 an experimental and comparative study about the engine emissions of conventional diesel engine and dual fuel engine ghazanfar mehdi1,2, syed asad ali zaidi1,3, m.mustafa azeem4, salman abdu1 abstract: because of the high thermal effectiveness, consistency, flexibility and economical cost diesel engines are extensively used all around the world. diesel engine emissions are producing serious environmental pollution which consists of oxides of nitrogen (nox), carbon monoxide (co) and particulate matter (pm). so it’s necessary to find the alternate solution to control diesel emissions. natural gas is a highly attractive due to its clean burning, low cost, and wide availability. in this experimental work, single cylinder (8.6 hp la186f) four-stroke conventional diesel engine was studied. natural gas is the major gaseous fuel used in dual fuel method which is up to 80% while diesel is used as a pilot fuel for the source of ignition up to 20%. in comparison with the conventional diesel method, it was observed that the dual fuel method significantly reduces the nox maximum up to 72.5%, carbon dioxide (co2) 34.5% and co 59.8%. however, hydrocarbon (hc) increased 66.76% in contrast with normal diesel combustion. during dual fuel mode, the emissions of hc and nox shows the inverse relation. keywords: diesel; dual fuel; emission; natural gas; combustion. 1. introduction diesel engines are extensively used in the public transportation because of their higher stability and thermal effectiveness. meanwhile, greenhouse gases are produced by transportation sector is about 30% of the world which leads to global warming [1]. therefore, diesel engine is more responsible for the serious atmospheric hazards [2]. nox and pm are the main harmful components of diesel engine. nox emission produces photochemical smog which is a major source of acid rain [3]. it has been proved by numerous studies that these gases can be 1 college of power and energy engineering, harbin engineering university, harbin, pr china. 2 faculty of engineering science and technology, indus university, karachi, pakistan 3 department of engineering sciences, pn engineering college, national university of sciences and technology, karachi, pakistan. 4 college of nuclear science & technology, harbin engineering university, harbin 150001, pr china. corresponding email: ghazanfarmehdi22@gmail.com enormously harmful to the environment, especially living beings as health hazard [4]. hence, emission regulations become stricter to reduce this environmental pollution. at the same time, energy consumption is growing rapidly and the fossil fuels are dwindling. in this regard, use of alternative fuels is necessary to meet the requirement of energy consumption and standard emission regulations. in public transport, natural gas is more environmental friendly among the various alternative fuels. because of its clean burning, widely spread distribution stations, and lower cost [5]. mailto:ghazanfarmehdi22@gmail.com ghazanfar mehdi (et al.), an experimental and comparitive study about the engine emissions of conventional diesel engine and dual fuel engine (pp. 81 87) sukkur iba journal of emerging technologies sjet | volume 1 no. 1 january – june 2018 © sukkur iba university 82 1.1. natural gas used as a substitute fuel in comparison by means of other alternative methods, the more attractive source of energy is natural gas used in the internal combustion engines[6]. natural gas has desirable advantages including low emission of greenhouse gases and reduction of capital costs. currently, due to environmental issues and energy shortage problems, governments of the worldwide are looking to the natural gas as a substitute fuel for conventional diesel engine [7]. 1.2. physiochemical properties of natural gas methane is the major part of natural gas which is near about 90%. . but with methane, it also consists of many numbers of gases namely ethane, propane, pentanes, n-butane and lightweight alkanes. nitrogen, carbon dioxide and traces of water vapors are also the components of natural gas. natural gas properties vary according to the composition, source of production, and process used. table 1 shows the composition of natural gas [8]. mostly, natural gas consists of 87–96% of methane. due to this reason, natural gas has same physical and chemical characteristics like methane. table 2 represents fuel properties of gasoline and diesel in comparison to natural gas [9–10]. in contrast with other fossil fuels, natural gas consists of less carbon per unit energy, therefore for public transport natural gas is environmental attractive as it produces low co2 emissions per mile. although, because of the higher auto-ignition temperatures of natural gas it is intricate to used it in diesel engines. however, for spark ignition engines natural gas is very favorable because of anti-knock quality. further, natural gas is used in diesel engines without auxiliary modifications. 2. dual fuel concept according to the dual fuel methodology, the intake manifold is used to mix the air stream and natural gas uniformly then it is introduced into the combustion chamber and pilot fuel with high table ii. physical and chemical characteristics of gasoline, natural gas and diesel [9–10]. fuel properties natural gas diesel gasoline low heating value(mj/kg) 48.6 42.5 43.5 heating value of stoichiometric mixture (mj/kg) 2.67 2.79 2.78 cetane number 52.1 13-17 octane number 130 85-95 auto-ignition temperature (°c) 650 180220 310 stoichiometric air-fuel ratio (kg/kg) 17.2 14.3 14.56 carbon content (%) 75 87 85.5 table i. typical components of natural gas [8]. content typical investigation (vol. %) range (vol. %) methane 94.9 87.0-96.0 ethane 2.5 1.8-5.1 propane 0.2 0.1-1.5 isobutane 0.03 0.01-0.3 n-butane 0.03 0.01-0.03 isopentane 0.01 trace to 0.14 n-pentane 0.01 trace to 0.14 hexane 0.01 trace to 0.06 nitrogen 1.6 1.3-5.6 carbon dioxide 0.7 0.1-1.0 oxygen 0.02 0.01-0.1 hydrogen trace trace to 0.02 ghazanfar mehdi (et al.), an experimental and comparitive study about the engine emissions of conventional diesel engine and dual fuel engine (pp. 81 87) sukkur iba journal of emerging technologies sjet | volume 1 no. 1 january – june 2018 © sukkur iba university 83 cetane number is used for ignition [11–12]. a systematic diagram of dual fuel mode is shown in fig. 1. in dual fuel mode, no serious modification is required. it is very easy to put in practice like a conventional diesel engine. however, this technology reduces more than 80% of diesel fuel [13]. the natural gas is introduced as a major gaseous fuel while diesel is only used for ignition purpose. hence the performance of dual fuel has been increased. with the use of dual fuel technology, the engine emissions decreased nox, co and pm emissions in comparison with a conventional diesel engine. meanwhile, some type of problems related to the dual-fuel mode such as thermal efficiency relatively low during operation of the engine at the small and moderate loadings. also, with the use of dual fuel emission of unburned hydrocarbon is increased considerably [14]. fig.1 is a schematic representation of dualfuel engine with its components highlighted in different colors. 3. engine emission characteristics 3.1. nitrogen oxides (nox) in diesel engines, nox emissions are very harmful. it consists of nitrogen dioxide (no2) and nitrogen monoxide (no). there are usually two mechanisms involved in the combustion mode which results in the nox formation namely as prompt mechanism (fenimore mechanism) and thermal mechanism (zeldovich mechanism). thermal nox depends upon the combustion temperature and amount of oxygen. in the thermal mechanism, if the engine in-cylinder temperature is higher than the 1800k, nox formation starts and it increases gradually with the increase of temperature [16]. in the prompt mechanism, during the fuel combustion hydrocarbon fragments especially ch2 and ch reacts with n2, resulting in the formation of prompt no, which is the c-n species [17]. thermal mechanism is accepted to be as the major contributor of nox during normal diesel engine operating conditions [18]. 3.2. carbon monoxide(co) co is the most detrimental emissions from a diesel engine. it is formed due to the presence of unburned fuel and in-cylinder combustion temperature. co is mostly produced because of oxygen shortage in the fuel rich area. also if the in-cylinder temperature is lower than 1450 k, co can be increased in the fuel lean area [19]. 3.3. hydrocarbon (hc) hc is also the outcome of unburned fuel in the combustion temperature. but for the entire oxidation, the temperature of hc is low. with the autonomy of actual fuel form, it has been observed to be near about 1200 k [20]. 3.4. carbon dioxide (co2) co2 is produced due to complete burning of fuel during the combustion process. however, the fuel is first oxidized into co, then due to the increase of combustion temperature and existence of oxygen concentration the fuel is further oxidized into co2. therefore, co2 highly rely on in-cylinder temperature and oxygen presence. fig. 1. the systematic diagram of dual fuel mode [15]. ghazanfar mehdi (et al.), an experimental and comparitive study about the engine emissions of conventional diesel engine and dual fuel engine (pp. 81 87) sukkur iba journal of emerging technologies sjet | volume 1 no. 1 january – june 2018 © sukkur iba university 84 4. experimental procedure a single cylinder four stroke engine (8.6 hp la186f) has been used. in this experiment, the engine emission effects of the diesel engine and dual-fuel engine are investigated. initially, diesel fuel is used for five minutes only without any load until the engine reaches to stable operating state. later engine speed is set at 1600 rpm through a throttle valve of the engine. a tricor mass flow meter, bronkhorst mass flow meter, and turbine mass flow meter were used for measuring the diesel fuel, natural gas, and air respectively. a portable gas analyzer (autologic company) was used to measure the exhaust emissions of the engine such as nox, co, co2, and hc. the calibration of the gas analyzer is necessary for obtaining the accurate measurements after each measurement. primarily, all the experiments conducted at maximum operating load, then with moderate operating loads and keeping same engine speed. the experiment was performed on three operating engine speeds 1600, 1800 and 2000rpm for efficient comparison. the engine was loaded till the maximum condition obtained for every speed. after finishing measurement on a diesel engine, it is necessary to cool engine for re-operation for accurate results. in the dual fuel mode, initially, it is very essential to warm the engine by supplying the pilot fuel for five minutes. then, natural gas is allowed to the cylinder, passing through the gas regulator. the pilot fuel remains unchanged throughout the experiment. but the flow of natural gas is increased only for obtaining and controlling the particular engine speeds. 5. results and discussion 5.1. exhaust emission for maximum and moderate load operating conditions 5.1.1. oxides of nitrogen (nox) it has been proved that in the dual fuel engine, nox emissions are reduced in both moderate and maximum operating loading conditions in comparison with conventional diesel fuel engine. in both conventional diesel mode as well as dual fuel mode nox emission increases with the rise of engine speed which also results in the rise of exhaust temperature. this can be represented in fig. 2. natural gas possesses a high value of specific heat capacity as compared with air. since with the use of natural gas overall heat capacity rises due to this reason mean temperature reduces close to the ending of the compression stroke and throughout the whole combustion practice. the nox formation is directly associated with the increase of engine in-cylinder temperature. however, the result is more efficient because at lower engine load combustion temperature is always reduced as the quantity of air and oxygen concentration lessen by means of natural gas. when the speed of the engine increases there is lesser time for the formation of nox because of which the emission of nox decreases. in dual fuel engine, ignition delay occurs because of the poor burning of natural gas. due to this in-cylinder temperature decreases which result in a reduction of nox emission. according to the dual fuel mode, nox emissions are reduced up to an average of 73% at maximum operating conditions and 72% at moderate operating conditions. consequently, overall nox reduction throughout the experiment is 72.5% that can be clearly seen in fig 2. ghazanfar mehdi (et al.), an experimental and comparitive study about the engine emissions of conventional diesel engine and dual fuel engine (pp. 81 87) sukkur iba journal of emerging technologies sjet | volume 1 no. 1 january – june 2018 © sukkur iba university 85 . fig. 3. exhaust co2 emission for maximum and moderate loading with different engine speeds fig. 2. exhaust nox emission for maximum and moderate loading with different engine speeds. 5.1.2. carbon dioxide it has been found that in the dual fuel mode, co2 emissions are reduced for both moderate and maximum operating loading conditions as compared with conventional diesel fuel engine as seen in fig. 3. in dual fuel mode, co2 emissions are lower because natural gas is low carbon content as compared with the diesel fuel. in dual fuel process, there is a problem of poor combustion because little amount of the fuel is not completely oxidized to co and flow out from the exhaust valve, which leads to the decrease of co2 emission. with the increase of engine speed, the amount of co2 emission also increases because the engine required more fuel. therefore the number of carbon contents increases in the combustion chamber. due to the larger carbon content chains in the diesel fuel, the range of co2 is higher at all speeds of engine. according to the dual fuel mode, co2 emissions are reduced up to an average of 37% at maximum operating conditions and 32% at moderate operating conditions. consequently, overall co2 reduction throughout the experiment is 34.5% that can be clearly seen in fig. 3. 5.1.3. carbon monoxide it has been proved that in the dual fuel mode the co emissions are reduced in both moderate and maximum operating loading conditions in comparison with conventional diesel fuel engine as shown in fig.4. however, if the engine is running at lower speed, co reduction is more noticeable. co is produced because of the incomplete fuel combustion, engine coldness and lacking of air concentration in the cylinder. with the decrease of air to fuel ratio, the amount of co increases, if the mixture is rich with fuel. in dual fuel mode, emissions of carbon monoxide decreased as compared with normal diesel engine with varying engine speeds. due to the better combustion efficiency of natural gas produces less amount of co, because natural gas is a gaseous fuel generally contains little quantity of contaminants than diesel fuel. ghazanfar mehdi (et al.), an experimental and comparitive study about the engine emissions of conventional diesel engine and dual fuel engine (pp. 81 87) sukkur iba journal of emerging technologies sjet | volume 1 no. 1 january – june 2018 © sukkur iba university 86 fig. 4. exhaust co emission for maximum and moderate loading with different engine speeds. with the increase of engine speeds, co emission increased in dual fuel method. however, when engine speed increases the dwelling time of fuel inside the cylinder shorten, resulting in superior co formation. according to the dual fuel mode, co emissions are reduced up to an average of 56% at maximum operating conditions and 63.66% at moderate operating conditions. consequently, overall co reduction throughout the experiment is 59.8% that can be clearly seen in fig.4. 5.1.4. hydrocarbons it has been observed in the dual fuel mode the amount of hc emissions are much more increased in both moderate and maximum operating loading conditions in comparison with normal diesel engine as shown in fig.5. however, the hc increased several times in comparison with normal diesel combustion. this is due to the incomplete combustion and remains of unburned fuel in the combustion chamber. in dual fuel mode, it shows trade-off connection in between hc and nox emission, due to less air to fuel ratio oxygen concentration is not enough for combustion process. the level of hc emissions are reduced when load increases, resulting in better efficiency for the combustion. due to this, it is observed that hc emission level is lower during maximum loading conditions. it has been found that in dual fuel method hc reduced when the engine speed is increased since the combustion process is better when the engine operates at high speeds. due to the scavenging process during the valve opening time, a small amount of air and natural gas mixture directly passed through the exhaust valve, which results the increase of hc. fig. 5. exhaust hc emission for maximum and moderate loading with different engine speeds. according to the dual fuel mode, hc emissions are increased up to an average of 78.5% at maximum operating conditions and 55% at moderate operating conditions. consequently, overall hc increment throughout the experiment is 66.76% that can be clearly seen in fig.5. 6. conclusion in this study, it has been established that a significant reduction takes place in nox, co2 and co emissions with the use dual fuel mode in comparison with the normal diesel engine. however, hc emission is increased several times in comparison with diesel fuel engine. in dual fuel mode, it shows the trade-off link in between hc and nox emission. therefore our investigation concludes that dual fuel engine is ghazanfar mehdi (et al.), an experimental and comparitive study about the engine emissions of conventional diesel engine and dual fuel engine (pp. 81 87) sukkur iba journal of emerging technologies sjet | volume 1 no. 1 january – june 2018 © sukkur iba university 87 more environmental friendly in contrast with diesel engine. references [1] pan hs, pournazeri s, princevac m, et al. effect of hydrogen addition on criteria and greenhouse gas emissions for a marine diesel engine. int j hydrog energy;39:11336–45, 2014. [2] w. tutak, k. lukács, s. szwaja, á. bereczky, alcohol–diesel fuel combustion in the compression ignition engine, fuel. 154,196–206. 2015. [3] l. stayner, d. dankovic, r. smith, k. steenland, predicted lung cancer risk among miners exposed to diesel exhaust particles,am. j. ind.med. 34 (3) 207–219. 1998). [4] j.d. mcdonald, m.d. reed, m.j. campen, e.g. barrett, j. seagrave, j.l. mauderly. [5] a. demirbas, methane gas hydrate: springer science & business media, 2010. [6] korakianitis t, namasivayam am, crookes rj. natural-gas fueled spark ignition (si) and compression-ignition (ci) engine performance and emissions. prog energy combust sci;37(1):89–112. 2011. [7] jin k, takashi o, yasuhiro d, ryouji k, takeshi s. combustion and exhaust gas emission characteristics of a diesel engine dual fueled with natural gas. jsae rev;21(4):489–96,2000. [8] a. demirbas, methane gas hydrate: springer science & business media, 2010. [9] q.c. zhang, g.s. chen, z.q. zheng, h.f. liu, j. xu, m.f. yao, combustion and emissions of 2,5-dimethylfuran addition on a diesel engine with low temperature combustion, fuel 103 730–735. 2013. [10] b.b. yang, m.f. yao, w.k. cheng, z.q. zheng, l. yue, regulated and unregulated emissions froma compression ignition engine under low temperature combustion fuelled with gasoline and n-butanol/gasoline blends, fuel 120 ,163–170. 2014. [11] o.m.i. nwafor, effect of choice of pilot fuel on the performance of natural gas in diesel engines, renew. energy 21 (3– 4),495–504. 2000. [12] a. paul, r.s. panua, d. debroy, p.k. bose, effect of compressed natural gas dual fuel operation with diesel and pongamia pinnata methyl ester (ppme) as pilot fuels on performance and emission characteristics of a ci (compression ignition) engine, energy 68 ,495–509, 2014. [13] r.g. papagiannakis, d.t. hountalas, c.d. rakopoulos, theoretical study of the effects of pilot fuel quantity and its injection timing on the performance and emissions of a dual fuel diesel engine, energy convers. manag. 48 (11) 2951–2961, 2007. [14] liu h, wang z, long y, xiang sz, wang jx, scott , wagnon w. methanol-gasoline dual-fuel spark ignition (dfsi) combustion with dual-injection for engine particle number (pn) reduction and fuel economy improvement. energy;89:1010–7, 2015. [15] wang-helmreich h, lochner s. the potential of natural gas as a bridging technology in low-emission road transportation in germany. therm sci;16(3)729–46, 2012. [16] j.b. heywood, internal combustion engine fundamentals: mcgraw-hill new york, 1988. [17] s.k. hoekman, c. robbins, review of the effects of biodiesel on nox emissions, fuel process. technol. 96, 237–249, 2012. [18] c.t. bowman, kinetics of pollutant formation and destruction in combustion, in: n.a. chigier (ed.), energy and combustion science (student edition one).,33–45 (pergamon1979). [19] t. kitamura, j. senda, h. fujimoto, mechanism of smokeless diesel combustion with oxygenated fuels based on the dependence of the equivalence ratio and temperature on soot particle formation, int. j. eng. res. 3 (4) 223–248. 2002. [20] j. liu, f. yang, h.w. wang, m.g. ouyang, s.g. hao, effects of pilot fuel quantity on the emissions characteristics of a cng/diesel dual fuel engine with optimized pilot injection timing, appl. energy 110,201–206, 2013. format template vol. 1, no. 1 | january june 2018 sjet | issn: 2616-7069 | vol. 1 | no. 1 | © 2018 sukkur iba 7 analyzing the impact of temperature on proton exchange membrane fuel cell performance using matlab aftab ahmed khuhro1 ,intizar ali2 ,safiullah2 abstract: the proton exchange membrane fuel cell (pemfc) is a device that converts the chemical energy of hydrogen into electrical energy. it receives hydrogen at anode and oxygen at the cathode side, due to chemical reaction at electrodes electronic current, along with that water and heat is also produced. heat produced causes problem for current produced, cell performance and may lead to a phase change of water produced. heat produced may also cause melting of the sensitive membrane and increase losses in a fuel cell. water produced causes flooding at electrodes and membrane which requires a specific amount of water only. this study used mat lab to analyze the impact of temperature on different parameters which have a significant effect on heat and mass flow. the results showed that the performance of proton exchange membrane fuel cell reduces with increase in temperature significantly during operation of the cell. the performance of fuel cell can be enhanced if the temperature of the fuel cell is controlled and kept within limits. proton exchange membrane fuel cell is suitable for transport, automobile, and other applications. keywords: heat; mass; fuel cell; transport; management; issues; mass flow; temperature; matlab. 1. introduction in the beginning of this century, the world has realized the shortage of fossil fuels which include mainly coal, gas, and oil. most of worlds energy demand is dependent on these natural resources. it is predicted that these resources will be very close to depletion in 2060. nuclear, solar, wind and other resources are considered as best option to replace the fossil fuels needed in future. however, still there will be a need for fuel to run high speed and heavy-duty vehicles of future and fuel cells are a suitable option for such a need [1]. 1 energy system engineering, sukkur iba university, sukkur, pakistan 2 department of mechanical engineering technology, the benazir bhutto shaheed university of technology and skill development, khairpur, pakistan corresponding email: aftab.mere17@iba-suk.edu.pk william grove is considered to be first to invent fuel cell in 1839. in 1960 nasa first commercialized the fuel cell by using them in their space missions [2]. after that, this technology was less discussed among researchers due to its shortcomings such as high cost and low efficiency. nonetheless, improving fuel cell performance by improving its design, material and optimizing performance has found new interest among researchers. proton exchange membrane fuel cells are the power source of future. many researchers are working on this technology to improve its performance and make it compatible with mailto:aftab.mere17@iba-suk.edu.pk aftab ahmed khuhro (et al.), analyzing the impact of temperature on proton exchange membrane fuel cell performance using matlab (pp. 7 14) sukkur iba journal of emerging technologies sjet | volume 1 no. 1 january – june 2018 © sukkur iba university 8 other fossil fuel technologies. pemfcs use pure hydrogen as fuel which can be produced using solar or wind power. hence this technology becomes clean, sustainable and emission-free technology [1]. pemfcs consist of a membrane, electrodes, gas diffusion layer, bipolar plates, and current collectors [2]. hydrogen at anode breaks into proton and electron. the membrane allows proton only to pass through and electrons flow through the external path to do some work. when hydrogen breaks at anode due to catalyst action, it is exothermic reaction hence heat is released [3]. water is produced at cathode when proton from membrane and oxygen through flow channels combine at cathode [4]. the reaction that occurs on both sides of the membrane is given below. anode 𝐻2 (g)→ 2𝐻 +(𝑎𝑞) + 2𝑒− (1) cathode 1 2 𝑂2 (𝑔) + 2𝐻 +(𝑎𝑞) + 2𝑒− → 2𝐻2𝑂 (𝑙) (2) overall 𝐻2 (𝑔) + 1 2 𝑂2 (𝑔) → 𝐻2𝑂 (𝑙) +ℎ𝑒𝑎𝑡 + 𝑒𝑙𝑒𝑐𝑡𝑟𝑖𝑐𝑖𝑡𝑦 (3) (3) heat and water produced are required in specific amount only [5]. if there is excessive heat, it will melt sensitive membrane and affect the efficiency drastically. and if water produced is in the excessive amount, it will cause flooding at electrodes, reducing the active area for reaction and reduce cell performance [6]. hence this study aims to analyze different fuel cell parameters which can affect heat and mass transfer phenomenon directly or indirectly. the connection of several fuel cell units in series and parallel will add up voltages and current which might be utilized in electric vehicles. this shows the importance of fuel cell electricity generation for the automobile industry. in order to optimize the performance of fuel cell, optimizing heat and mass problem is necessary. most of fuel cell performance parameters depend on heat and mass transfer phenomenon [9]. fig. 1. pem fuel cell diagram [3]. fig. 2. flow channels and flow directions [5]. fig. 3. exploded view of pem fuel cell [16]. aftab ahmed khuhro (et al.), analyzing the impact of temperature on proton exchange membrane fuel cell performance using matlab (pp. 7 14) sukkur iba journal of emerging technologies sjet | volume 1 no. 1 january – june 2018 © sukkur iba university 9 2. methodology this study is based on numerical analysis of heat and mass transfer issues due to variation of different parameters during operation of the fuel cell. this paper focuses on the impact of temperature variation during cell working and observes the impact on the performance of cell by choosing a different range of operating parameters and analyzed them using the available commercial software. rather choosing many parameters and observing their effect cell this study is focused on the temperature of the cell which is considered as a most important factor of fuel cell performance. thus, understanding the fuel cell temperature and its behavior becomes very important. 2.1. mass transport and water management in order to produce the continuous power, we need a continuous supply of fuel at the anode side of the cell. added with that excessive surplus water produced as the output of reaction should be removed continuously. voltage and current reduction may be caused due to three kind of losses of fuel cell activation, concentration and ohmic losses [10]. mass transport is a flow of species within the cell and by optimizing flow and analyzing their effect on cell performance we can predict cell behavior. water produced may cause the membrane to rupture or occupy active places where reaction needs to take place [11]. ∑(𝑚𝑖 ) 𝑖𝑛 = ∑(𝑚𝑖 ) 𝑜𝑢𝑡 (4) mass balance of cell system should be mass that goes into system equals that leaves the system. 𝑤𝑒𝑙 = 𝑛𝑐𝑒𝑙𝑙 𝑉𝑐𝑒𝑙𝑙 𝐼 (5) however, cell power can be expressed as given in equation above where n_cell represents the number of cells, v_cell represents cell voltage and i is current of cell. the higher flow rates cause the better distribution of reactants. if the flow rate is too high that may rupture sensitive membrane. there are basically two types of flow within the cell. one is by convection that occurs in flow channels and the other is diffusive which is due to pores of diffusion layer and electrodes [12]. hence the study of mass transport and water management become important to properly design fuel cell. different parameters and constants are used to study the behavior of cell performance when temperature changes with time of operation. table i. the parameters and constants used in this study to analyze the effect of temperature on fuel cell performance. parameters symbol constant value thermal conductivity (k) depends on material heat transfer rate (q) ------ ideal gas constant (r) 8.314 faraday's constant (f) 96487 transfer coefficient (⍺) 0.5 enthalpy depends on temperature thermal resistance (r) ----- 2.2. heat management the temperature in pemfcs is always unsteady even if flow rate at both electrodes is kept constant. temperature variations within the cell due to water phase change, heat produced by the chemical reaction, water flooding within the cell and air convection [13]. aftab ahmed khuhro (et al.), analyzing the impact of temperature on proton exchange membrane fuel cell performance using matlab (pp. 7 14) sukkur iba journal of emerging technologies sjet | volume 1 no. 1 january – june 2018 © sukkur iba university 10 determining heat distribution within the cell is key to determine temperature variations and predict them properly. operating temperature is an important parameter that can affect the efficiency of the cell. temperature control, distribution and dynamic response are very important to understand for better performance of the cell. it is necessary for proper operation of fuel cell stack that optimum values should be known for parameters such as temperature. some researcher has shown that temperature has the greatest effect on cell performance [14]. operation of fuel cell stack is an uncertain process and the temperature is a parameter that has the highest uncertainty during operation. water transport is directly affected by operating temperature of the cell. it also affects flow species, removal of water, and flooding at electrodes [15]. heat distribution can be determined using energy balance on the system. the energy balance depends on several factors such as power produced, reactions and heat loss on walls of the cell [16]. the enthalpy of a system that enters the system is equal to the enthalpy of products plus heat generated. the rate of heat transfer with cross-section area a is given below. 𝑞𝑥 = −𝑘𝐴 𝑑𝑇 𝑑𝑥 (6) where k is thermal conductivity and 𝑑𝑇 𝑑𝑥 is a temperature gradient. l represents the length and t1 and t2 are initial and final temperatures. 𝑞𝑥 = 𝑘 𝑇1 − 𝑇2 𝐿 (7) thermal resistance associated with conduction in the plane wall is given as 𝑅𝑐𝑜𝑛𝑑 = 𝑇1 − 𝑇2 𝑞𝑥 = 1 𝑘𝐴 (8) heat transfer through conduction between two adjacent materials in contact is given as 𝑞 = ℎ𝑡𝑐 𝐴∆𝑇 (9) where ℎ𝑡𝑐 is convective heat transfer coefficient. thermal resistance associated with heat transfer by convection is given as 𝑅𝑐𝑜𝑛𝑣 = 𝑇1 − 𝑇2 𝑞𝑥 = 1 ℎ𝐴 where h is enthalpy. since conduction and convection are in series they can be written mathematically as 𝑅𝑡𝑜𝑡𝑎𝑙 = 1 ℎ1𝐴 + 𝐿 𝑘𝐴 + 1 ℎ2𝐴 𝑞 = 𝑈𝐴∆𝑇 the considering fuel cell walls as composite and in series total heat transfer can be written as equation above where u is overall heat transfer coefficient. the fuel cell system runs efficiently when there is precise control of temperature. at higher temperature, the kinetics will be faster and reduce activation losses. but higher temperature may damage the membrane so it is required at an optimum level. higher temperature will also cause water to vaporize and change its phase from liquid to gas. small fuel cell stack does not require cooling but larger stack requires cooling for homogenous temperature distribution and control [17]. heat distribution can be controlled by properly designing flow channels and bipolar plates. introducing cooling channels with bipolar plates additional heat can be removed. 3. results and discussion the objective of this study is to analyze and observe the impact of temperature on fuel cell losses, performance, entropy, current produced, consumption of fuel and reversible cell potential. temperature is an important parameter that has an effect on heat and mass parameters. temperature has a low impact on the entropy of mass species during operation of the cell. aftab ahmed khuhro (et al.), analyzing the impact of temperature on proton exchange membrane fuel cell performance using matlab (pp. 7 14) sukkur iba journal of emerging technologies sjet | volume 1 no. 1 january – june 2018 © sukkur iba university 11 the entropy of h2, o2, and water does not show significant change while temperature increases during operation. water management at membrane in cell stack is very important because ionic current flows through the hydrated membrane. heat is generated at anode which causes dehydration of membrane. on the other hand, water generated at cathode may cause flooding if generation rate is higher than transport rate. both the hydration and flooding at cathode depends on heat generated by fuel cell reaction and both dehydration of electrolytic membrane and flooding of cathode must be avoided to get optimum performance of cell stack. fig. 4. the impact of temperature on the entropy of mass species. fig. 5. the impact of temperature on activation losses. however, the temperature has a significant impact on activation losses of the cell. if temperature increases the activation losses increases with that exponentially. hence temperature control during operation of the cell becomes very important to limit activation losses. heat and mass species play an important role in cell performance and are related to temperature directly or indirectly. temperature also plays an important role in current produced by the cell, hydrogen consumed at the anode and total electricity produced by the cell. this study shows that if temperature increases with that current produced by cell decrease significantly. the significant loss in total electricity produced is also observed. due to increase in temperature number of moles consumed at the anode side of pemfcs also reduces. the less current produced and moles at anode show that performance of cell reduces with increase in temperature. the results show that reversible cell potential also reduces with increase in temperature. hence temperature has a negative impact on reversible potential which will add further loss in fuel cell performance and efficiency to operate at high temperature. temperature has a positive impact on cell current density. if temperature increases cell electrode kinetics increases along with electrode kinetics limiting current density increases. the key findings of this study would be following. 1. temperature has less impact on entropy but it accelerates the kinetic reaction at first along with an increase in activation losses. 2. reversible cell potential values reduced with increasing temperature. aftab ahmed khuhro (et al.), analyzing the impact of temperature on proton exchange membrane fuel cell performance using matlab (pp. 7 14) sukkur iba journal of emerging technologies sjet | volume 1 no. 1 january – june 2018 © sukkur iba university 12 table ii. effect of temperature on cell current, electricity produced and h2 consumed at the anode. temperat ure (k) current produc ed (a) electrici ty produce d no of moles consum ed (h2) 298.15 1.9733 1.70×10 5 0.8835 303.15 1.9467 1.67×10 5 0.8689 308.15 1.9092 1.64 ×105 0.8548 313.15 1.8788 1.62×10 5 0.8412 318.15 1.8492 1.59×10 5 0.8280 323.15 1.8206 1.57×10 5 0.8151 328.15 1.7929 1.54×10 5 0.8027 333.15 1.7660 1.52×10 5 0.7907 338.15 1.7399 1.50×10 5 0.7790 343.15 1.7145 1.48×10 5 0.7676 348.15 1.6899 1.46×10 5 0.7566 353.15 1.6660 1.43×10 5 0.7459 3. the less fuel was consumed due to increase in temperature which is not good for the overall performance of the cell. table iii. effect of temperature on reversible cell potential. temperature (k) reversible cell potential 298 1.2289 303 1.2247 308 1.2205 313 1.2163 318 1.2120 323 1.2036 328 1.1993 333 1.1909 343 1.1902 353 1.1824 363 1.1740 373 1.1655 fig. 6. the impact of temperature on limiting current density. 4. conclusion this paper shows that temperature has a significant impact on current produced within fuel cell stack compared to entropy of mass species. as the temperature rises due to heat released during reaction taking place at electrodes, current and electricity produced aftab ahmed khuhro (et al.), analyzing the impact of temperature on proton exchange membrane fuel cell performance using matlab (pp. 7 14) sukkur iba journal of emerging technologies sjet | volume 1 no. 1 january – june 2018 © sukkur iba university 13 are reduced. there was a continuous drop in hydrogen consumption at electrodes due to rise in temperature. the lesser consumption of hydrogen fuel at anode leads to the minimum amount of current and electricity production. temperature also affects the activation losses of the cell, the increase in temperature active places at anode and cathode of cell show more resistance for reaction. the operation time to calculate cell current and other parameters was chosen 24 hours. during this period number of moles calculated and converted in liters at 25oc are 19.79 liters. the number of liters consumed at 80oc ware 16.70. it can be concluded that with higher temperature cell tends to consume less fuel as compared to low temperature, which will eventually result in low performance and reliability of pemfcs. acknowledgment authors would like to thank dr. fareed hussain mangi and dr. saeed ahmed khan abro for their valuable suggestions. authors also thank reviewers for their valuable comments and suggestions. references [1] s. shafiee, & e. topal, “when will fossil fuel reserves be diminished?,” energy policy, vol. 37, no. 1, pp. 181-189, 2009. [2] a. arvay, a. ahmed, x.-h. peng, and a. kannan, "convergence criteria establishment for 3d simulation of proton exchange membrane fuel cell," international journal of hydrogen energy, vol. 37, pp. 2482-2489, 2012. [3] c. siegel, "review of computational heat and mass transfer modeling in polymerelectrolyte-membrane (pem) fuel cells," energy, vol. 33, pp. 1331-1352, 2008. [4] a. arvay, proton exchange membrane fuel cell modeling and simulation using ansys fluent. arizona state university, 2011. [5] j. carton and a. olabi, "threedimensional proton exchange membrane fuel cell model: comparison of double channel and open pore cellular foam flow plates," energy, vol. 136, pp. 185-195, 2017. [6] r. b. ferreira, d. falcão, v. oliveira, and a. pinto, "numerical simulations of twophase flow in proton exchange membrane fuel cells using the volume of fluid method–a review," journal of power sources, vol. 277, pp. 329-342, 2015. [7] s. cano-andrade, a. hernandezguerrero, m. von spakovsky, c. damian-ascencio, and j. rubio-arana, "current density and polarization curves for radial flow field patterns applied to pemfcs (proton exchange membrane fuel cells)," energy, vol. 35, pp. 920927, 2010. [8] x.-d. wang, y.-x. huang, c.-h. cheng, j.-y. jang, d.-j. lee, w.-m. yan, et al., "flow field optimization for proton exchange membrane fuel cells with varying channel heights and widths," electrochimica acta, vol. 54, pp. 55225530, 2009. [9] d. spernjak, a. k. prasad, and s. g. advani, "in situ comparison of water content and dynamics in parallel, singleserpentine, and interdigitated flow fields of polymer electrolyte membrane fuel cells," journal of power sources, vol. 195, pp. 3553-3568, 2010. [10] m. zhukovsky, l. fomina, and s. beznosyuk, "computer modeling of hydrogen fuel cell subsystems: carbon nanogel electrodes and fractal nanoparticle catalysts," international journal of hydrogen energy, vol. 36, pp. 1212-1216, 2011. [11] l. karpenko-jereb, p. innerwinkler, a.m. kelterer, c. sternig, c. fink, p. prenninger, et al., "a novel membrane transport model for polymer electrolyte fuel cell simulations," international aftab ahmed khuhro (et al.), analyzing the impact of temperature on proton exchange membrane fuel cell performance using matlab (pp. 7 14) sukkur iba journal of emerging technologies sjet | volume 1 no. 1 january – june 2018 © sukkur iba university 14 journal of hydrogen energy, vol. 39, pp. 7077-7088, 2014. [12] a. manso, f. marzo, j. barranco, x. garikano, and m. g. mujika, "influence of geometric parameters of the flow fields on the performance of a pem fuel cell. a review," international journal of hydrogen energy, vol. 37, pp. 1525615287, 2012. [13] p. k. sinha, c.-y. wang, and u. beuscher, “transport phenomena in elevated temperature pem fuel cells,” journal of the electrochemical society, vol. 154, pp. b106-b116, 2007. [14] a. bıyıkoğlu, “review of proton exchange membrane fuel cell models,” international journal of hydrogen energy, vol. 30, pp. 1181-1212, 2005. [15] j.-h. jang, w.-m. yan, and c.-c. shih, “effects of the gas diffusion-layer parameters on cell performance of pem fuel cells,” journal of power sources, vol. 161, pp. 323-332, 2006. [16] t. wilberforce, z. el-hassan, f. khatib, a. al makky, j. mooney, a. barouaji, et al., “development of bi-polar plate design of pem fuel cell using cfd techniques,” international journal of hydrogen energy, vol. 42, pp. 2566325685, 2017. [17] a. a. khuhro, y. ali, m. najam-uddin, and s. khan, “a technological, economical and efficiency review of direct methanol fuel cell,”. design of a centralized intelligent expert system and contamination detection of tissue cultured sugarcane crop vol. 4, no. 2 | july –december 2021 sjet | p-issn: 2616-7069 |e-issn: 2617-3115 | vol. 4 no. 2 july – december 2021 64 investigating the effect of active cooling on grid connected solar power plant in sukkur, sindh, pakistan aftab ahmed1, mujahid ali2, shehdev thahrani2, arshad hussain jamali2, sultan ahmed3, abdul qadeer khoso2, zahid ali2 abstract solar cells produce current by consuming photons energy, generating electron-hole pairs. solar modules are notoriously sensitive to ambient temperature. new studies put forward shows that global warming would lead to reduced power output across the globe by the year 2100. climate change is going to have a substantial impact on solar power output and incident sunlight is a varying quantity in terms of time and location. sunlight is a visible electromagnetic wave that falls into the thermal wavelength category and causes the temperature of the solar cell to augment considerably. one challenge linked with solar cells is that they only capture visible light in the ultra-violet and infra-red spectrum. higher blue and green energy photons provide higher energy than required for an electron to excite from valence band to conduction band. for hot regions like sukkur, this problem plays a great role in impeding solar cell’s performance. another reason for the rise in temperature is ohmic resistance inside module due to metallic current collecting lines. hence, every single oc rise in cell temperature causes a significant power loss. numerous studies have been shown to reduce solar panel temperature and enhance their performance. this study uses a water cooling scheme to improve the performance of poly and mono-crystalline panels. the central objective of this study is to estimate the potential surge in power yield of 849 kw solar plant installed at sukkur iba university, sukkur, pakistan by the introducing water cooling scheme. results indicated considerable improvement in the module performance and estimated an added 10% improved power yield. keywords: photons; thermal wavelength; pv cell temperature; passive cooling; ohmic resistance 1. introduction with the hot regions like upper sindh, pakistan experience higher ambient temperatures, high solar irradiance, and dry 1mechanical engineering department isra university hyderabad, pakistan 2science and technology department, indus university karachi, pakistan 3department of mathematics, shah abdul latif university corresponding author: aftabkhuhro12@gmail.com conditions. the foremost reason for higher ambient temperatures other than equatorial topography is global warming and consequent climate change. some regions receive more mailto:aftabkhuhro12@gmail.com investigating the effect of active cooling on grid connected solar power plant in sukkur, sindh, pakistan (pp. 64 72) sukkur iba journal of emerging technologies sjet | vol. 4 no. 2 july – december 2021 65 sunlight than others because of cloud shelter, atmospheric water content, and aerosols [1]. the output of the solar module drops as operating temperature rises with the passage of day time. it is more concerning that how climate change is going to affect photovoltaic performance and how to cool pv cells properly is still a poorly studied area. the main aspect that affects solar cell performance is nonradiative recombination [2]. recombination takes out the electrons from the conduction band and recombines with holes that lead to a drop in power. this is because electrons do not get a chance to do external work [3]. recombination is opposite phenomenon to generation as electron loses its energy and tries to stabilize itself in valance band again provided that as electron loses its energy in the form of heat, temperature of panel also rises. this recombination effect is directly linked with temperature, as the temperature rises this rate of recombination also raises, leading to a loss in output yield. the parameters such as open-circuit voltage voc, short circuit current isc, fill factor (ff) and efficiency are temperature-dependent parameters [4]. the voc decreases considerably and isc increases marginally with the rise in temperature. the overall performance of solar cells decreases with an increase in temperature and also causes an increase in internal losses in the form of recombination [6]. investigating the temperature dependence and effect on voc and isc is critical in the field of solar research. the diode parameters of the solar module such as ideality factor (n), series resistance (rs), reverse saturation current (io), and shunt resistance (rsh) are the key factors that define the possible effect of temperature on voc, ff, and z of the solar cell. the solar cell p-n junction i-v characteristics can be described by the following mathematical equation [7]. 𝐼𝑓 = 𝐼𝑝ℎ − 𝐼𝑜 (𝑒 𝑞𝑉𝑗 𝑛𝐾𝑇 ⁄ − 1) − 𝑉𝑗 𝑅𝑠ℎ ⁄ (1) where 𝑉𝑗 = 𝑉𝑓 + 𝐼𝑓 𝑅𝑠 (2) here, iph represents photo generated current which is approximately equal to the short circuit current and io is reverse saturation current. vj is voltage dropped across the junction, n being ideality factor, t as temperature and k represents boltzmann constant. the terminal voltage, series resistance, and shunt resistance are represented by vf, rs and, rsh respectively [8-10]. 𝑉𝑜𝑐 = 𝑛𝑉𝑇 . ln ( 𝑖𝑝 + 𝐼𝑜 𝐼𝑜 ) (3) where vt is voltage equivalent of temperature, i_p is photocurrent. the currentvoltage characteristics of the solar module depend on temperature as isc increases with temperature and voc decreases due to the positive and negative temperature coefficients. the pmax also drops with a rise in temperature as it has also a negative temperature coefficient. the overall impact would be a significant loss in the performance of solar modules due to an increase in temperature [1113]. fig 1: total energy yield during the year 2019 hence, this study focus on the different effects of temperature on the solar module performance and preventive water cooling technique. experimental and numerical studies are conducted to compare and observe different behavior of i-v characteristics of the solar modules. the objective of this study is to see whether water or radiative cooling could be a more efficient technique for solar module performance enhancement [14-17]. investigating the effect of active cooling on grid connected solar power plant in sukkur, sindh, pakistan (pp. 64 72) sukkur iba journal of emerging technologies sjet | vol. 4 no. 2 july – december 2021 66 fig 2: the power yield during the month of july we analyzed an 849 kw solar pv plant and found that during the year 2019 the maximum power generated in may was less than 500 kw as. this power can be increased greatly with cooling techniques either by passive or active cooling [18-20]. 2. methods the performance of a pv cell depends on the solar spectral distribution of irradiance and reference spectra. solar cell parameters are mostly measured at standard temperature conditions (stc) [21-24]. the optical losses occur due to the reflection of glass at the front and for fixed-tilt angle latitude, clearance index, surface treatment, and refractive indices are the main factors on which optical losses depend. 2.1. specific module selection the performance of solar module can greatly be increased with different cooling methods such as water cooling, radiative cooling, and convective cooling. this study focused on the cooling of module using water and an enhancement in the performance of the module. the cooling technique applied had a uniform cooling effect on the entire surface area of the panel. the total number of modules selected was 6. it was made sure that during cooling there should be a uniform cooling at the glass surface; however, it was not entirely possible at all. fig 3: the total power produced in 20172019 fig 4: the climate conditions of the studied region [25] table 1 the climate & weather averages in sukkur parameter value high temp 41 °c low temp 30 °c mean temp 35 °c precipitation 11.2 mm investigating the effect of active cooling on grid connected solar power plant in sukkur, sindh, pakistan (pp. 64 72) sukkur iba journal of emerging technologies sjet | vol. 4 no. 2 july – december 2021 67 humidity 53% dew point 24 °c wind 6 km/h table 2 the specifications of the studied pv modules. parameters values area of single panel 1.64 m2 tilt angle of panels (polycrystalline) 15o tilt angle of panels (monocrystalline) 5o ideal voc 37.4 v ideal isc 8.63 a ideal power 322.76 w ideal voc single cell 0.6233 v azimuth angle for panels understudy 410 total system power 849 kw fig 5: the equipment used for the measurements the equipment used for this study were multimeter, irradiance meter, and a digital laser thermometer. the front and backside temperatures of modules were measured when modules were covered with dust and after the dust was removed. the effect of dust shading was also observed on voc and isc of the module. the performance of the solar module is mostly determined by the voc and isc. the readings were measured during the month of july as shown in figures. 3. results and discussion isc increases with irradiance and decrease marginally with the temperature. however, the short circuit voltage decreases with rising temperature logarithmically. voc is more sensitive to temperature than isc. the increase in isc due to temperature is very small approximately 0.45% per degree rise. however, the voc drop and heat produced causing ohmic losses to contribute to a more overall loss in performance. hence, this study shows how much we can achieve with a simple water cooling method. fig 6: front and backside temperatures of modules at higher irradiance it was observed that the front side temperature was 1-2 degrees lesser than the backside of the module. this must be due to the glass layer at the front which does not allow all light to reflect and causing more heat at the backside of the panel. this could be also due to current collecting lines present at the backside, when current is produced and travels 1 2 3 4 5 6 irradiance 760 backsidetemperature 62.1 61.4 62.3 61.4 62.9 62.1 frontsidetemperature 60.1 59.2 58.3 57.3 60.4 59.4 0 100 200 300 400 500 600 700 800 irradiance backsidetemperature frontsidetemperature investigating the effect of active cooling on grid connected solar power plant in sukkur, sindh, pakistan (pp. 64 72) sukkur iba journal of emerging technologies sjet | vol. 4 no. 2 july – december 2021 68 through backside current collecting buses it experiences more resistance compared to the front side. this higher temperature at backside of module also contributes negatively to the performance of the module. fig. 6 indicates that temperature rises with increasing irradiance level. but in the post afternoon time when irradiance decreases but the temperature still remains higher. that rise in temperature at a lower irradiance level compared to morning. fig 7: irradiance vs temperature relation fig. 7 indicates that voc increases with increasing irradiance but at in evening time the voc decreases the solar panels under study have all cells connected in series to add up the voltage. when cells are connected either in series or parallel fill factor does not change. however, it does change when cells are not identical by manufacturing aspect and cells are not receiving an equal amount of light. hence, non-uniform light scattering over panel and disparity in manufacturing cause a difference in fill factor. table 3-4 indicates that before and after cooling voc, isc recovers considerably. the temperature decreases with cooling and it augments with fill factor and performance of the module substantially. fig 8: the behavior of voc with irradiance fig. 8 clearly shows that there is a significant increase in power yield of panels after active cooling through the water. hence, roughly speaking there can be a 55 kw increase in power yield of sukkur iba university’s total monthly power yield. the amount of power used for active cooling is small and water consumption can also be controlled. hence, the 45th total power increase is much higher than what it requires to run the motor for the active cooling of solar panels. water spray over the front surface of the module reduces reflection losses and absorbs heat accumulated inside pv panels. the power yield improvement and operating temperature reduction were higher at noon than morning or evening time this space is intentionally left blank to adjust table on other page . 1 2 3 4 5 6 irradiance w/m2 640 714 760 705 688 576 temperat ure oc 57.759.458.361.4366.960.4 52 54 56 58 60 62 64 66 68 0 100 200 300 400 500 600 700 800 irradia nce w/m2 tempe rature oc linear (temp erature oc) 0 100 200 300 400 500 600 700 800 900 33.00 33.20 33.40 33.60 33.80 34.00 34.20 34.40 34.60 34.80 irradiance w/m2 voc investigating the effect of active cooling on grid connected solar power plant in sukkur, sindh, pakistan (pp. 64 72) sukkur iba journal of emerging technologies sjet | vol. 4 no. 2 july – december 2021 69 table 3 before and after cooling parameters s .n o v o c ( v ) b e fo re c o o li n g i s c ( a ) b e fo re c o o li n g b a c k s id e te m p e ra tu re b e fo re c o o li n g f ro n t si d e te m p e ra tu re b e fo re c o o li n g f il l fa c to r b e fo re c o o li n g v o c ( v ) a ft e r c o o li n g i s c ( a ) a ft e r c o o li n g f ro n t si d e t e m p e ra tu re (o c ) b e fo re c o o li n g f ro n t si d e t e m p e ra tu re (o c ) a ft e r c o o li n g f il l fa c to r a ft e r c o o li n g 1 31.20 7.10 62.1 60.1 0.68 34.61 7.95 62.0 44.1 0.85 2 32.40 6.43 61.4 59.2 0.64 34.00 7.92 60.5 46.8 0.83 3 32.33 6.09 62.3 58.3 0.61 33.64 7.98 62.3 47.7 0.83 4 31.29 6.23 61.4 58.6 0.60 34.71 8.06 61.3 50.5 0.84 5 32.40 6.28 62.9 60.4 0.63 34.05 7.95 64.2 45.3 0.84 6 32.60 7.00 62.5 59.5 0.70 33.85 7.93 65.6 45.8 0.86 fig 9: the difference between the power output of the module before and after the cooling the both active and passive cooling methods are considered as suitable method in terms of energy saving generated through solar. however, the passive cooling method is more economically viable and more effective method. fig. 9 &10 shows that with cooling method voc, isc increases, especially voc improves a lot. which contributes to the total power yield enhancement. fig 10: illustration of power comparison before and after cooling the major reason for the improvement in voc is greatly due to the reduction in the operating temperature of the module with active cooling. the top black curve represents the ideal iv curve at 1000 w/m2, am 1.5 and 25 0c. the middle three curves represent after cooling iv curves, which are clearly above the before cooling bottom three curves. it is 133 151 120 127 121 77 162 201 222 207 153 69 0 50 100 150 200 250 1 2 3 4 5 6 before cooling power (w) investigating the effect of active cooling on grid connected solar power plant in sukkur, sindh, pakistan (pp. 64 72) sukkur iba journal of emerging technologies sjet | vol. 4 no. 2 july – december 2021 70 evident that cooling shifts the iv curves to the top which means an improvement in the performance of the module. fig 11: the power voltage curves based on experimental calculation the power voltage curves show that after cooling curves are near to the ideal curve as shown in the black ideal curve at the top. the before cooling curves however are more shifted towards the bottom side indicating that less power was produced before cooling of the module. 3.1 numerical results fig 12: temperature contours of solar glass surface after water cooling fig. 12 indicates that the glass surface temperature reduces unevenly with the water cooling method. even though temperature distribution is not smooth but operating temperature falls with increasing reynolds number as concluded from the numerical simulations. the maximum cooling was achieved at reynolds number 15 and minimum at 5. furthermore, the operating temperature was achieved below the desired value with a higher reynolds number. the temperature at top of the module is much lower compared to the bottom of glass. this is due to water is sprayed from the top and it absorbs some of the heat while reaching the bottom of the module. the variation of contours in figure 12 indicate the validity of results as in practice it is observed that there is always variable temperature distribution across solar plate surfaces. fig 13: the temperature distribution in the frontal plane fig. 13 indicates that the temperature of the module reduces the maximum from the point where the water starts flowing downwards. the water cooling does not cool operating temperature below 25 0 c. the overall module temperature drop using numerical technique was around 23 0 c. 4. conclusion this study shows the power yield of the solar plant greatly reduces due to the dust and rise in operating temperature. the temperature rise after 2 pm is higher and the irradiance level investigating the effect of active cooling on grid connected solar power plant in sukkur, sindh, pakistan (pp. 64 72) sukkur iba journal of emerging technologies sjet | vol. 4 no. 2 july – december 2021 71 continues to decrease after 1 pm. the rise in temperature, reduction in irradiance level and no tracking cause great loss in total power yield of the plant. during the study, it was observed that the backside temperature was higher than the front side. backside temperature also leads to resistance in backside metallic current collection points. temperature relation with irradiance was not entirely linear due to wind effect and changing environment such as clouds. several other effects cause non-linear behavior of temperature with irradiance. however, voc increases with irradiance and reduces when irradiance decreases. the power yield graph clearly illustrates that power improves greatly with passive cooling. the vi curve shows that after cooling vi curves are more close to the ideal iv curve. which means after cooling power yield is significant increases. the rain greatly improved the 849 kw solar plant. before rain 849 kw produced a maximum 550 kw. however, after rain, the maximum power yield reached the 605 kw mark. hence, there were almost 55 kws enhancements in the performance of the solar plant. on average 2.2 tons of co2 has been avoided by the 849 kw plant. if this plant is regularly cleaned and cooled than the maximum yield might reach 650 kw. the total energy yield for the month of september was higher than 4000 kwh through the highest outcome is expected is in the month of may and june. it is therefore suggested that regular cleaning and cooling of the module installed at sukkur iba university will surely boost total yield. solar panels are constructed by connecting solar cells in array form. there are more than 15 different categories of solar cells are designed until now and most of them are not commercialized yet due to different reasons, such as stability issues and efficiency issues while different techniques are being applied to improve the stability or efficiencies of solar cells [26,27]. rise in temperature is one of the major issues in stability of thin film solar cells. however in this paper, experimental work is totally based on conventional silicon solar cells. this research can further be conducted on thin films solar cells to improve the stability and efficiency which are the main barrier in commercializing of thin film solar cell. 5. future recommendations 1. find the heating rate and cooling rate of pv panels. 2. determine optimized flow rate for optimized reduced operating temperature. references [1] peters, i. m., & buonassisi, t. (2019). the impact of global warming on silicon pv energy yield in 2100. arxiv preprint arxiv:1908.00622. [2] singh, p., singh, s. n., lal, m., & husain, m. (2008). temperature dependence of i–v characteristics and performance parameters of silicon solar cell. solar energy materials and solar cells, 92(12), 1611-1616. [3] green, m. a. (2003). general temperature dependence of solar cell performance and implications for device modelling. progress in photovoltaics: research and applications, 11(5), 333-340. [4] azzouzi, m. e. s. s. a. o. u. d. a., & stork, m. i. l. a. n. (2014). modelling and simulation of a photovoltaic cell considering single-diode model. recent advances in environmental science and biomedicine, 175-182. [5] https://www.sunnyportal.com/fixedpages/plantpro file.aspx [6] moharram, k. a., abd-elhady, m. s., kandil, h. a., & el-sherif, h. (2013). enhancing the performance of photovoltaic panels by water cooling. ain shams engineering journal, 4(4), 869-877. [7] bahaidarah, h., subhan, a., gandhidasan, p., & rehman, s. (2013). performance evaluation of a pv (photovoltaic) module by back surface water cooling for hot climatic conditions. energy, 59, 445453. [8] mah, c. y., lim, b. h., wong, c. w., tan, m. h., chong, k. k., & lai, a. c. (2019). investigating the performance improvement of a photovoltaic system in a tropical climate using water cooling method. energy procedia, 159, 78-83. [9] kabeel, a. e., & abdelgaied, m. (2019). performance enhancement of a photovoltaic panel with reflectors and cooling coupled to a solar still with air injection. journal of cleaner production, 224, 40-49. [10] khordehgah, n., guichet, v., lester, s. p., & jouhara, h. (2019). computational study and experimental validation of a solar photovoltaics and thermal technology. renewable energy. investigating the effect of active cooling on grid connected solar power plant in sukkur, sindh, pakistan (pp. 64 72) sukkur iba journal of emerging technologies sjet | vol. 4 no. 2 july – december 2021 72 [11] asim, m., dewsbury, j., & kanan, s. (2016). trnsys simulation of a solar cooling system for the hot climate of pakistan. energy procedia, 91, 702-706. [12] muneer, t., maubleu, s., & asif, m. (2006). prospects of solar water heating for textile industry in pakistan. renewable and sustainable energy reviews, 10(1), 1-23. [13] abdulgafar, s. a., omar, o. s., & yousif, k. m. (2014). improving the efficiency of polycrystalline solar panel via water immersion method. international journal of innovative research in science, engineering and technology, 3(1), 96-101. [14] bhutto, a. w., bazmi, a. a., & zahedi, g. (2012). greener energy: issues and challenges for pakistan—solar energy prospective. renewable and sustainable energy reviews, 16(5), 2762-2780. [15] solangi, k. h., islam, m. r., saidur, r., rahim, n. a., & fayaz, h. (2011). a review on global solar energy policy. renewable and sustainable energy reviews, 15(4), 2149-2163. [16] harijan, k., uqaili, m. a., & memon, m. (2008, april). renewable energy for managing energy crisis in pakistan. in international multi topic conference (pp. 449-455). springer, berlin, heidelberg. [17] shah, a. a., memon, z. a., shafaq, s., shah, a., & sethar, w. (2017). renewable energy technologies diffusion in sindh: an overview. mehran university research journal of engineering and technology, 36(3), 673-680. [18] teo, h. g., lee, p. s., & hawlader, m. n. a. (2012). an active cooling system for photovoltaic modules. applied energy, 90(1), 309-315. [19] esfahani, j. a., rahbar, n., & lavvaf, m. (2011). utilization of thermoelectric cooling in a portable active solar still—an experimental study on winter days. desalination, 269(1-3), 198-205. [20] nguyen, x. h., & nguyen, m. p. (2015). mathematical modeling of photovoltaic cell/module/arrays with tags in matlab/simulink. environmental systems research, 4(1), 24. [21] el-shobokshy, m. s., & hussein, f. m. (1993). effect of dust with different physical properties on the performance of photovoltaic cells. solar energy, 51(6), 505-511. [22] valeh-e-sheyda, p., rahimi, m., karimi, e., & asadi, m. (2013). application of two-phase flow for cooling of hybrid microchannel pv cells: a comparative study. energy conversion and management, 69, 122-130. [23] kumar, p., shukla, a. k., sudhakar, k., & mamat, r. (2017). experimental exergy analysis of watercooled pv module. international journal of exergy, 23(3), 197-209. [24] alam, s. m. s., & rahman, a. m. (2016, january). performance comparison of mirror reflected solar panel with tracking and cooling. in 2016 4th international conference on the development in the in renewable energy technology (icdret) (pp. 1-4). ieee. [25] beck, h. e., zimmermann, n. e., mcvicar, t. r., vergopolan, n., berg, a., & wood, e. f. (2018). present and future köppen-geiger climate classification maps at 1-km resolution. scientific data, 5, 180214. [26] danish khan, zahid ali, danyal asif, manoj kumar panjwani, idris khan,incorporation of carbon nanotubes in photoactive layer of organic solar cells,ain shams engineering journal, 2020. [27] lebbi, m., touafek, k., benchatti, a., boutina, l., khelifa, a., baissi, m. t., & hassani, s. (2021). energy performance improvement of a new hybrid pv/t bi-fluid system using active cooling and selfcleaning: experimental study. applied thermal engineering, 182, 116033 format template vol. 4, no. 1 | january – june 2021 sjet | p-issn: 2616-7069 |e-issn: 2617-3115 | vol. 4 no. 1 january – june 2021 34 design and development of sindhi text based captchas for regional websites asadullah kehar1, rafaqat hussain arain1, riaz ahmed shaikh1, safdar ali shah1, fida hussain khoso2, imtiaz ahmed dahar3, ali hussain jiskani1, shereen fatima1, hidayatullah shaikh1 abstract: bots are created to use the resources maliciously on world wide web. the misuse of the resources could be prevented by employing captchas. several types of captchas are being used against the bots (robot) attacks but text-based captcha type is the most popular being very secured and easy to use. latin language based text captchas can be found ubiquitously on internet but english text based captchas are already decoded by many researchers. thus, a novel sindhi language based text captcha was proposed for regional websites where arabic style script was utilized. this scheme offered two fold benefits: first, the proposed scheme could easily be understood by averagely literate person; second, this scheme paved a way for arabic style ocr developers to understand sindhi language specific features and facilitate sindhi text recognition in future. a survey was also conducted to analyze the usability and strength of proposed captcha. keywords: captcha; sindhi text; bots; internet security; optical character recognition. 1. introduction captcha (computer adapted public turing test to tell computer and humans apart) is test to separate computers from humans. sindhi or other arabic script based captcha is an easy way to distinguish between sindhi/arabic understanding humans and computers. currently, arabic ocrs are not adequately developed to recognize sindhi or other arabic text whereas english ocrs are developed for recognizing the english or other latin scripts, hence, sindhi text can only be recognized by sindhi text understanding people. a novel sindhi text-based captcha, an image with sindhi text embedded is proposed for regional websites to prevent bots attack. sindhi words (meaningful as well as 1department of computer science, shah abdul latif university, khairpur, pakistan 2dawood university of engineering & technology, karachi pakistan 3deparment of computer systems engineering, quaid-e-awam uest, nawabshah, pakistan corresponding author: riaz.shaikh@salu.edu.pk meaningless words) were utilized for proposed scheme. initially, sindhi words were generated and saved as image format then some distortions were introduced in the image and finally users were asked to recognize and type-in the word appeared in image. in order to recognize sindhi text-based captcha some basic knowledge of sindhi language is required. segmentation of characters is the main task for recognition of captchas [1] but the segmentation of sindhi words is quite complex due to sindhi text features: variable charactersizes, overlapping characters, detecting base asadulllah kehar (et al.), design and development of sindhi text based captchas for regional websites (pp. 34 44) sukkur iba journal of emerging technologies sjet | vol. 4 no. 1 january – june 2021 35 lines and containing sub-words. furthermore, ocrs for arabic scripts are font specific; therefore ocrs developed for particular font may not recognize the other fonts. sindhi and other arabic text-based languages contain similar shaped letter-groups; the only difference among the letter-groups is number and location of attached dots. recognition of these similar letter-groups is real challenge for ocrs. the new captcha is proposed by realizing above mentioned characteristics of the sindhi text. in this era of ubiquitous computing almost every service is shifted to cloud based webservices. the web-based software is more efficient and cost-effective as compared to offline software. in order to use the web-based software, users need to register themselves via filling online forms. furthermore, bots are malicious programs designed to misuse the internet resources (e.g. sending spam emails, signing into several profiles, making nasty registrations and distributed denial-ofservice (ddos) attacks [2-4]. captchas are used to prevent these automatic bots attacks [56], however, bots have also become intelligent in decoding captchas with scrambled text [7] . most of the captchas used on web are in english, latin, european or other east asian languages, captchas are not yet designed in urdu (national language of pakistan) or sindhi (regional language in pakistan). therefore, more secure and easily readable captchas were required for regional sindhi websites. in this regard, sindhi captcha was proposed to be incorporated in local sindhi websites which could be understood by averagely literate persons. sindhi is one of major four regional languages spoken in sindh, pakistan, around 50 million of people speak sindhi in pakistan and in some parts of india as well. the most popular sindhi script is derived from arabic script and the text comprised of 52 cursive table i. 52 alphabets of sindhi language and their english equivalent serial no. sindhi alphabets equivalent english alphabet serial. no. sindhi alphabets equivalent english alphabet serial. no. sindhi alphabets equivalent english alphabet ph ڦ d 37 د a 19 ا 1 k ق dh 38 ڌ b 20 ب 2 k ڪ d 39 ڏ b 21 ٻ 3 kh ک d 40 ڊ bh 22 ڀ 4 g گ d 41 ڍ t 23 ت 5 g ڳ z 42 ذ th 24 ٿ 6 gh گھ r 43 ر t 25 ٽ 7 g ڱ r 44 ڙ th 26 ٺ 8 l ل z 45 ز s 27 ث 9 m م s 46 س p 28 پ 10 n ن sh 47 ش j 29 ج 11 n ٹ s 48 ص j 30 ڄ 12 w, v و z 49 ض jh 31 جھ 13 h ھ t 50 ط j 32 ڃ 14 a ء z 51 ظ ch 33 چ 15 y, i ي a, aa 52 ع chh 34 ڇ 16 gh غ h 35 ح 17 f ف kh 36 خ 18 asadulllah kehar (et al.), design and development of sindhi text based captchas for regional websites (pp. 34 44) sukkur iba journal of emerging technologies sjet | vol. 4 no. 1 january – june 2021 36 letters. table 1. depicts 52 letters of sindhi and the english equivalent is also shown against each sindhi alphabet. the rest of the article is divided as follows: section 2 discusses literature review. section 3 describes the characteristics of sindhi and arabic scripts. section 4 discusses about the proposed methodology and section 5 and 6 presents the analysis about proposed sindhi captcha and conclusion respectively. 2. literature review most of the sindhi regional websites use english text-based captchas, which were decoded by bots as they consisted on isolated english alpha numeric letters bandey et al., [8] introduced captchas in urdu which comprised on single-word, double words and 4-9 letters word images. these urdu captchas were readable but not secure and could be broken by arabic ocrs. arain et al. [9] discovered that captchas used in local e-commerce websites were vulnerable and were decoded achieving a success rate around 82.4%. khan et al., [10] suggested a method that used arabic script for generation of captchas. specific arabic font type was used for captcha generation. arabic ocr limitations for reading arabic text were exploited by the suggested scheme. the proposed scheme proved useful in protecting internet resources in arabic speaking countries. the survey results for evaluation of usability and robustness were found satisfactory. yaghmaee and kamyar[11] introduced three different kinds of persian captchas in different domains. the first type of captcha was based on the contiguous writing characteristics of persian writing and image processing. in second type, the meanings of persian words were utilized for creating captchas and in third type the mixture of image processing and meaning of words were used. the proposed scheme was found secure and persian people could easily recognize captchas. shirali-shahreza and shirali-shahreza[12] presented a method cantered on persian/arabic text. the algorithm based on adding background to the image of randomly generated and meaningless persian/arabic word. the method depended on difficulty of partitioning of background from writing due to presence of dots and diacritic signs. this method was tested against available persian/arabic ocrs and the ocrs were unable to recognize the words. daharet al., [13] suggested that captchas may be designed in local and regional languages including urdu and sindhi for improving the security, understand ability and accessibility of the regional websites. they proposed urdu text-based captcha for local urdu websites. the authors had highlighted the limitations of already available captchas and compared the efficiency of the proposed captcha scheme. alsuhibany et al., [14] evaluated the robustness of state of the art arabic captchas. they demonstrated that a number of proposed arabic captchas could fig. 1. plan of work asadulllah kehar (et al.), design and development of sindhi text based captchas for regional websites (pp. 34 44) sukkur iba journal of emerging technologies sjet | vol. 4 no. 1 january – june 2021 37 be decoded with a satisfactory success rate. some recommendations were offered as guide for designing arabic robust captchas. shaikh et al.[15] presents the contemporary approach for object recognition by the fusion of low level features and spatial layout. low level features are very important for content based image retrieval, further hussain et al., [16] discussed innovative idea for the segmentation of connected characters in the text based captchas for character recognition. in fig. 1. the plan of work is explained. kehar et al. [17] decoded partially connected characters with background clutter in a text-based captcha scheme. 3. characteristics of sindhi and arabic scripts familiarity with sindhi text or with other arabic scripts is mandatory for designing and implementing sindhi captchas. in following sections, the characteristics of arabic text, in general, and the characteristics of sindhi text, in particular, will be discussed. the key feature of sindhi and other arabic scripts is the order of writing: sindhi is written or typed from right to left direction unlike english text, which is written from left to right direction however some other languages are even written from top to bottom order. therefore sindhi captcha should be recognized from right to left direction. english language has two forms: upper case letters and lower case letters but sindhi and other arabic texts have at least four forms depending upon position of letter in word as in table 2. character recognition complexity increased due to these different forms. the possible four forms of letter ‘sheen’ could either be standalone‘ ش’, initial ‘ شـ’, medial ‘ ـشـ’ or final sindhi language has some similar letter .’ـش‘ groups in table 3. the difference is in number of dots and location of dots. this table also shows some compound letters, of sindhi language, which are created by combining two primary shaped letters; for instance ( ھ= جھ + are also ( و and د) look alike alphabets .(ج shown in the table. in this work, all the alphabets of sindhi text are classified on the basis of number of dots and position of dots, see table 4. this table also shows five classes of letters, depending on number of attached dots(without dot, one dot, two dots, three dots and four dots) and the position of dot(s) is also emphasized (either above baseline or below baseline). since dot could mistakenly be considered noise and table ii. sindhi alphabets at different positions group pronunciation standalone initial medial final first aleef ا ا ا ا second bhe ـڀ ـڀـ ڀـ ڀ third ne ـڃ ـڃـ ڃـ ڃ fourth daal ـڏ ـڏ ڏ ڏ fifth re ـڙ ـڙ ڙ ڙ sixth sheen ـش ـشـ شـ ش seventh zuwaad ـض ـضـ ضـ ض eighth zuay ـظ ـظـ ظـ ظ ninth ghen ـغ ـغـ غـ غ tenth phhay ـڦ ـڦـ ڦـ ڦ eleventh ghay ـڳ ـڳـ ڳـ ڳ twelfth roon ـڻ ـڻـ ڻـ ڻ thirteenth hay ـھ ـھـ ھـ ھ fourteenth laam ـل ـلـ لـ ل asadulllah kehar (et al.), design and development of sindhi text based captchas for regional websites (pp. 34 44) sukkur iba journal of emerging technologies sjet | vol. 4 no. 1 january – june 2021 38 could be omitted while noise removing phase therefore dot might play an important role during recognition phase. another potential challenge may be total count of dot(s) because connected dot(s) might be counted incorrectly therefore could lead to inaccurate recognition of letters. one of the important features of sindhi is its cursive/connected text. sindhi text (handwritten as well as machine printed) is available only in cursive form, hence the segmentation of sindhi text is confirmed to be difficult. the letters of sindhi script does not have fixed sizes, for instance, while printing, the letter “ء” will occupy less space than letter and the recognition of different sized ”گ“ letters become difficult. besides the space that usually exists between words, there are cases when small space exists between segments of the same word: for example the word “ احسان” has 3 segments,” حسا“ , ”ا “ and “ ن”. now this situation could be confusing for machines and it is hard to recognize the three segments as single word. diacritics is a way to correctly understand and pronounce the words. in sindhi and arabic almost similar diacritics: zer, zabar and paish are put above/below the letters (e.g. zer ( مسِجد : place of worship), zabar (َحَجم : hair dresser) and paish ( ٺ ا : camel) ). it is challenging, to differentiate the words, without diacritics for ocr programs. 4. proposed methodlogy in order take advantages of the discussed features of sindhi script a new sindhi-text based captcha is proposed against bots attacks. the framework for creating the sindhi text-based captchas described in parallel by realizing the conventional development of english text-based captchas. 4.1. adding noise and background to the image generally, noise is added in background of captcha images so that ocr programs may fall off to segment and recognize the letters. nowadays, new techniques are applied for background noise removal especially for english text-based captchas but in case of sindhi/arabic type scripts, since dots and diacritics signs are involved, it is difficult to remove noise. the noise removal may eliminate the recognition-required elements like dots and diacritic symbols besides noise. therefore, the proposed scheme suggested algorithm for adding noise in a way so that if noise is removed, it may result in removing the essential element as well and this could lead to incorrect recognition of the captcha characters. colored ellipses and clutter were inserted in the proposed captcha table iii. the similar letter groups in sindhi alphabets groups 1st 2nd 3rd 4th 5th 6th 7th 8th 9th 10th 11th 12th 13th ا ھ ن ک ف ع ط ص س ر د ج ب ل ٹ گ ڦ غ ظ ض ش ڙ ڌ ڄ ٻ ج +ھ ڳ ق ز ڏ ڃ پ جھ م ي ڱ ء ڊ چ ڀ گ+ھ ڍ ڇ ت گھ ڪ ذ ح ٿ خ ٽ ٺ و ث asadulllah kehar (et al.), design and development of sindhi text based captchas for regional websites (pp. 34 44) sukkur iba journal of emerging technologies sjet | vol. 4 no. 1 january – june 2021 39 4.2. using a random word some english text-based captcha methods uses meaningful words in which captcha is taken from dictionary, while, it is easy for user to type the captcha word but the word could also be guessed easily by ocr software. thus, during this project, meaningless sindhi words were preferred whenever user convenience was least required. this obviously minimized the flexibility of reading sindhi words but offered more secured captcha text. although, it is difficult for user to type the long and meaningless captcha text but lengthy and meaningless string can complicate the recognition process, therefore, sindhi meaningless text having 3 to 8 letters were specified for proposed scheme. the generated string was image rather than text and then this image was distorted, by adding different types of noise, in a way that only human could recognize the text in image. 4.3. design and implementation of proposed scheme captcha design was carried out with the plan that machines may not be able to recognize the text, enabling against bots attacks. the color scheme for background and foreground seems beautiful for human eyes but it is intentionally kept difficult for ocr program in segmenting the essential text only. successful baseline recognition aids in process of segmentation therefore characters are randomized in way that complicate the detection of baseline. overlapping characters were deliberately used so that captcha table iv. classification of sindhi letters based on number of dots and position of dots without dot one dot two dots three dots four dots above ا baseline above baseline above baseline above baseline ٿ ٽ ت خ ح ڙ ث ٺ ذ د ڏ ڌ ز ر ڦ below ش ق ض س baseline below ڱ ظ ص baseline ڀ below غ ط baseline ڇ پ چ ٻ ف ع ڄ ن ڪ below ک baseline ڃ ڍ ب گ ڳ ج گھ ي جھ ل ڊ م ٹ و ھ ء asadulllah kehar (et al.), design and development of sindhi text based captchas for regional websites (pp. 34 44) sukkur iba journal of emerging technologies sjet | vol. 4 no. 1 january – june 2021 40 ocr programs could hardly segment the string. a novel framework for creating sindhi captcha was proposed as shown in fig. 2. on the basis of the proposed framework an application programming interface (api) was created in c# programming language. the api was created in dll form and could be packaged in microsoft nuget format to be shared among web developers. any web application (asp.net) can incorporate api without requiring any out-sourced software and could be added in any project by simply adding reference to dll file. the proposed framework is extensible and thus api could be configured as per user requirements. user can easily modify captcha settings: number of words, character for each word, meaningful or meaningless words, and database settings as either internal or external database, number of ellipses or other noise. if user does not change the settings then default settings would be applied. the default settings are: single meaningful word with size between 3 to 8 characters. meaningful word will be selected randomly from sindhi database. in case the user has selected meaningless word then random characters are joined to create meaningless word and isolated characters are fig. 2. framework for design and implementation of sindhi captcha asadulllah kehar (et al.), design and development of sindhi text based captchas for regional websites (pp. 34 44) sukkur iba journal of emerging technologies sjet | vol. 4 no. 1 january – june 2021 41 intentionally discarded to ensure the cursive format of the words. random function is synchronized with system-time. initially blank image was created with dimensions 200 x 80. then ellipses and other noise were added. default settings for ellipses and other noise was kept in 20s and 50s respectively. the framework was implemented by creating two projects: one project for creating ‘sindhicaptcha api’ and the other project for ‘sindhi-captcha web testing’ by implementing the api. the public method of api may be invoked to access the captcha’s image and answer/text. initially, sindhi captcha sign up page was visited, while visiting the page, an http ‘request’ was generated towards back-end (asp.net server) then sindhi-captcha api was used and a captcha was generated, on the basis of pre set configuration. afterwards, this newly generated captcha was sent to front-end as ‘response’ and answer of captcha was stored in session. when user may enter the captcha text on front-end then this text will be sent to back-end for verification against already stored answer. if the user’s entered text and its answer matched then user can proceed further on front-end web form. user’s basic information: first name, last name, e-mail, batch, discipline and familiarity with sindhi typing; was gathered on front-end sign up form for future use. 4.3.1 sindhi words collection approximately 280000 different words were gathered from various resources comprising android-based sindhi dictionaries, on-line websites and pdf books. words were gathered with the help of custom developed software and banked into sql database. fig. 3. sign-up form for sindhi captcha asadulllah kehar (et al.), design and development of sindhi text based captchas for regional websites (pp. 34 44) sukkur iba journal of emerging technologies sjet | vol. 4 no. 1 january – june 2021 42 4.3.2 design and development of api for sindhi captchas sindhi captcha sign-up form is shown in fig. 3. api has several interfaces for generating different captchas depending on user’s requirements: • number of words for each captcha • number of characters for each word • meaningful / meaningless captchas • font types for captcha text • internal/external database the following isolated letters were eliminated in creating joint sindhi words while creating meaningless captcha: ,ا ر ,ڙ,ز , د ,ڏ, و , ذ 4.3.3 api implementation: front-end implementation was carried out with the help of web technologies; html5, css3, bootstrap, jquery. the testing and analysis of the proposed system was accomplished through sample web form. api was tested and analyzed with the help of several students arranged in several groupings. to implement the proposed sindhi captcha web-domain was also purchased. 5. analysis about proposed sindhi captcha captcha efficiency is assessed through its usability and robustness. usually, there is a trade off between readability and security of captcha: when a captcha is adequately secured that it might not be broken by machines but at same time if it is not comprehensible by human user then captcha is considered useless, hence a captcha is assumed valuable whenever a human can read the captha easily. an analysis was carried out for inspecting the readability of proposed scheme by more than 80 students arranged in various groupings corresponding to age, subject-discipline and level of understanding of sindhi script. sindhi captchas were tested in arabic based ocr: readiris and tesseract, but both of the ocr software could not recognize any of the sindhi captcha completely. the proposed scheme was also assessed against other existing schemes to assess understand ability, effectiveness of captchas and security checked by exercising ddos attacks. 5.1. captcha testing web-form in order to analyze the effectiveness of newly proposed sindhi captcha, an api was developed and implemented in asp.net (web-forms). more than 80 university students tried the api. several captchas single word, double words, meaningful and meaningless were generated. sindhi fig. 4. sindhi captcha test form asadulllah kehar (et al.), design and development of sindhi text based captchas for regional websites (pp. 34 44) sukkur iba journal of emerging technologies sjet | vol. 4 no. 1 january – june 2021 43 captcha test form is depicted in fig. 4. numerous students were registered on the captcha testing web-form. the web-form demonstrated the following statistical data: • 60 users knew very little about sindhi or urdu typing • 46 were beginners and they knew about sindhi or urdu typing to some extent. • 46 were average users (intermediate). • few users were good at sindhi or urdu typing (advanced) length of captcha words was set between 3and 8 characters per word. it was noted that students were not much attracted to complex captchas and therefore they did not attempted to resolve complex captchas. 2260 captchas were inputted by 160 students. • 132 correct • 739 incorrect • 200 renew 6. conclusion an api of sindhi captcha was developed. api was implemented in web application (asp .net). the api for sindhi captcha was assessed by several students from shah abdul latif university (www.salu.edu.pk). lastly, api was also tested against two online ocr programs to evaluate the strength of developed api. it was observed that single meaningful captchas were appropriate for users to be decoded with ease. straight captchas (without diacritic signs) should be eliminated to keep the high strength of captchas. length of word(s) might be reduced to maximum 6 letters per word. future schemes should be designed in web api form so that users may not need to add the api in their projects. web api could be accessed through every type of webapplications: jsp, php, python, ruby and so on. sindhi and other arabic style captchas are in early stages of development despite numerous text-based captcha schemes. semantic based sindhi text captcha should be designed in future which may be presented to user after removing the dots from letters and may be asked to type in the related letters. the people who understand sindhi, must have vocabulary in their mind therefore they can enter the accurate answer easily but computers could hardly guess all the letters of captcha. author contribution all authors contributed equally to the work. data availabilty statement the datasets generated during and/or analyzed during the current study are available from the corresponding author on reasonable request. conflict of interest the authors declare no conflict of interest. funding not applicable. references [1] zheng, l.; hassin, a.h.; and tang, x. (2004). a new algorithm for machine printed arabic character segmentation. pattern recognit. lett., 25(15), 1723–1729. [2] ahn, l.v.; blum, m.; and langford, j. (2004). telling humans and computers apart automatically. communications of the acm, 47(2), 56-60. [3] yan, j.; and el ahmad, a.s. (2008). usability of captchas or usability issues in captcha design. 4th symposium on usable privacy and security proceeding. new york, 44–52. [4] khan, b.; alghathbar, k.s.; khan, m.k.; alkelabi, a.m.; and alajaji, a. (2010). using arabic captcha for cyber security. commun. comput. inf. sci., 122, 8–17. [5] chellapilla, k.; larson, k.; simard, p.; and czerwinski, m. (2005). designing human friendly human interaction proofs (hips). asadulllah kehar (et al.), design and development of sindhi text based captchas for regional websites (pp. 34 44) sukkur iba journal of emerging technologies sjet | vol. 4 no. 1 january – june 2021 44 sigchi conference on human factors in computing systems proceedings. montreal 711-720. [6] el ahmad, a.s.; yan, j.; and marshall, l. (2010). the robustness of a new captcha. proceedings of the 3rd european workshop on system security, eurosec’10, 36–41. [7] bursztein, e.; martin, m.; and mitchell, j.c. (2011). text-based captcha strengths and weaknesses. proc. acm conf. comput. commun. secur. 2011, 125–137. [8] banday, m.t.; and shah, n.a. (2011). challenges of captcha in the accessibility of indian regional websites. 4th annu. acm bangalore conf. 0–3. [9] arain, r.h.; shaikh, r.a.; kumar, k.; maitlo, a.; kehar, a.; shah, s.a.; and shaikh, h. (2018). verifying the robustness of textbased captchas offered by local ecommerce sites. int. j. comput. sci. netw. secur., 18(9), 79–84. [10] khan, b.; alghathbar, k.; khan, m.k.; alkelabi, a.; and alajaji, a. (2013). cyber security using arabic captcha scheme. int. arab j. inf. technol., 10(1) 76–84. [11] yaghmaee, f.; and kamyar, m. (2016). introducing new trends for persian captcha. j. electr. comput. eng. innov., 4(2), 119–126. [12] shirali-shahreza, m.h.; and shirali-shahreza, m. (2006). persian/arabic baffletext captcha. j. univers. comput. sci., 12(12). 1783–1796. [13] dahar, i.a.; alvi, f.a.; and rajput, u. (2020). enhancing security of urdu language websites through urdu captcha. international journal of computer science and network security, 20(11), 142–151. [14] alsuhibany, s.a.; parvez, m.t.; alrobah, n.; almohaimeed, f.; and alduayji, s. (2017). evaluating robustness of arabic captchas. 2nd international conference on anti-cyber crimes, icacc 2017, 81–86. [15] shaikh, r.a.; memon, i.; arain, r.h.; maitlo, a.; and shaikh, h. (2018). a contemporary approach for object recognition using spatial layout and low level features’ integration”, multimedia tools and applications. [16] hussain, h.; gao, h. and shaikh, r.a. (2016). segmentation of connected characters in text-based captchas for intelligent character recognition. multimedia tools and applications. [17] kehar, a.; arain, r.h; and shaikh, r.a. (2020). deciphering complex text-based captchas with deep learning. indian journal of science and technology 13(13), 1390-140 format template vol. 1, no. 1 | january june 2018 sjet | issn: 2616-7069 | vol. 1 | no. 1 | © 2018 sukkur iba 72 design of artificial neural network based power split controller for hybrid electric vehicle engr.aqsa kk1, noor u zaman laghari2 abstract: the progress of a society and degree of civilization is increasing, major factor behind it is a said developing cars. due to this increasing numbers of cars the pollution because of emission of internal combustion engine (ice) in environment is increased and also fuel consumption is increased. to reduce the said fuel consumption and said environment pollution hybrid electric vehicle (hev) attracted many researchers to work on it. in this research paper, work presented to minimize the said fuel consumption a power spilt controller is designed based on artificial neural network (ann) between two propelling source electric motor (em) and ice the data is taking through dynamic programing-the research is done to achieve better said fuel economy in nonlinear parallel hybrid electric vehicle (phev).in the ann controller one input layer, one output layer, and two hidden layers are used. the matlab-simulation is used for the implementation and numpy-library is used for the training of the data. all the simulation result are discussed. the trained data is used. the data is tested on three driving cycle named nedc, us06 and ftp-75 for both the thermal and hybrid vehicles. keywords: artificial neural network; dynamic programing; parallel hybrid electric vehicle; new european driving cycle; federal test procedure;us06. 1. introduction from many years a big attention has been inclined to the problems of automobiles consumption of fuel reduction and more highway vehicles. concomitantly very ample concentration has been paid on emission pollutants reduction through automobiles and other vehicles. at higher temperatures if operated an engine then it can be realized the fuel consumption reduction and increased in the efficiency of thermodynamics. in engines substantial interest has been erected of ceramic materials endure higher combustion temperatures than those in active now [1]. on 1 department of mechatronics engineering ,mehran uet jamshoro , pakistan 2 department of computer systems engineering, mehran uet jamshoro, pakistan corresponding email: aqsa.kk@unifiedcrest.com the other hand higher combustion temperatures in engines fuelled with gasoline cause to increase in certain undesirable pollutants, typically nox. one proposal is vehicles use should be limited which is powered by said ice and instead employs the em which are powered electric vehicles (ev) powered by said rechargeable batteries for reducing the pollution in the cities. all such electric cars (ec) have no more than 150 miles typically limited range, for hill climbing and acceleration having an insufficient power mailto:aqsa.kk@unifiedcrest.com engr aqsa kk (et al.), design of artificial neural network bases power split controller for hybrid electric vehicle (pp. 72 80) sukkur iba journal of emerging technologies sjet | volume 1 no. 1 january – june 2018 © sukkur iba university 73 other than when the batteries are charged fully, and require ample time for the recharging battery. thus the finite range and extended batteries recharge time would not be an inconvenience in many circumstances and for all the travel necessity of most individuals such cars are not suitable [2]. accordingly, for most users an electric car (ec) would have to be an supplementary vehicle, arranging a substantial economic deterrent. moreover, coal-fired power plants is the source of generation of most electricity in the us (united states) and it will be appreciated, so using electric vehicles (ev) merely moves the point of supply of the pollution, but doesn’t eliminate it .the respective net costs comparison of driving per mile, ethanolfuelled vehicles (efv) are not competitive with ev, with conventional gasoline-fuelled vehicles (gfv) [3].create these components, incorporating the applicable criteria that follow.  drive torque is supplied by a power unit to said output shaft and two or more drive wheels receiving torque for propelling said vehicle from an output shaft.  a controllable torque transfer unit (ttu) adapted to receive torque from two sources through first and second input shafts and transmit the torque to said output shaft.  an engine adapted to consume combustible fuel and supply torque to said torque transfer unit.  an electric motor (em) supply torque to said torque transfer unit and from a battery adapted to receive electricity.  a stored electric energy in a battery is supplied to said motor and when motor is operated as a generator the storing electric energy received from a motor.  for controlling the operation of electric motor (em), engine and torque transfer unit (ttu) a controller is used, such that torque transfer unit (ttu) receives said torque.  from either or both of electric motor (em) and internal combustion engine (ice) through first and second input shafts and transmit the torque from drive wheels by way of output shaft, for controlling the relative contributions of the em and ice to the said torque driving the wheels. where in the relative ratio of the rate of rotation of a said output member of torque transfer unit (ttu) to the rate of rotation of driven wheels, and the relative ratios of the rates of rotation of engine and em to input shafts are fixed [4]. in many application of control system artificial neural networks (ann) have been favorable used. but the learning algorithm based on ann shows a great accomplishment when used off-line it means that before implementation they have to be fully trained. “an networks have extensively parallel distributed processor and have an natural propensity for storing developmental knowledge and making this knowledge accessible for use” by haykin (1994). the an networks also resemble to the brain of the human in two aspects, they having a network similar to human brain networks and acquires a knowledge via a learning process and second they have an synaptic weights which is used to store these acquire knowledge. similar to black box model an networks require no detail information of the system. instead, by studying the previous record data these neurons learn the relationships among the various input parameters. the an networks have an ability that it can handle enormous and complex system with many interrelated parameters.an networks concentrates on the more substantial inputs and ignores the input data having minimum significance. our aim is to design a controller strategy which is based on an networks in which controller takes substantial input and give it to the vehicle for the desired output [5-6]. the problem statement is: engr aqsa kk (et al.), design of artificial neural network bases power split controller for hybrid electric vehicle (pp. 72 80) sukkur iba journal of emerging technologies sjet | volume 1 no. 1 january – june 2018 © sukkur iba university 74 1. the problem considered is to minimize the fuel consumption of an hev that reconciles the drivers demanded vehicle velocity, by designing a controller for the parallel hybrid electric vehicle. 2. many researchers worked on dynamic programing and neural network for energy management individually. 3. to our best knowledge combine the both strategies for the better energy management and fuel economy that are presented in this research, have not been addressed. the aim of this research work is  to compute the optimized fuel optimization and power split between ice and em using dynamic programing (off-line).  to develop an artificial intelligence based power-split controller for real time driving condition.  to train and test the design controller using the data from off-line optimization result.  test and simulate the designed controller for real time condition.  compare and contrast the results with existing strategies/controller for slandered driver cycle. 2. literature review chan, c.c [7] developed rules based on heuristics, intelligence of the humans and math’s model generally without prior knowledge of a drive cycle. these implementation rules are executed through lookup tables to share the demand of power between ice and electric traction motor to meet driver requirements and other peripherals (electrical loads, battery) in the most effective technique. a good fuel economy as well as at the same time drivability and dynamic performance is also improved. hofman et al [8] research based on rulebased and equivalent consumption minimization strategies (rb-ecms). only one main design parameter is used and of many threshold control values and parameters no tuning is required. this design parameter represents the secondary power source maximum propulsion power (i.e. electric machine/battery) during pure electric driving. comparison of rb-ecms with the strategy based on dp. in this paper the rb-ecms proposed requires significantly inferior computation time with the result similar as dp (within §1% accuracy). jhun hana et al [9]-[10] the equivalent consumption minimization strategy (ecms) is often considered as practical avenue while driving in the real world situation with uncertainties such as rugged road ecms is used to control parameter as stated in rugged road so that the state of charge (soc) is maintain inside the boundary and give the distinct improvement in fuel economy. jinming liu and huei peng [11] developed ths power train dynamic model and then apply it for model-based control development. introduced 2 control algorithms: one based on the stochastic dynamic programming method, and the second based on the ecms. both approaches determine the engine power depend on the overall vehicle efficiency to optimize engine operation apply to the electrical machines. these 2 algorithms performance is evaluate by comparing against the dynamic programming results, which are non-causal but provide theoretical benchmarks for more implementable control algorithms. 3. model of parallel hybrid electric vehicle 3.1. vehicle parameter engr aqsa kk (et al.), design of artificial neural network bases power split controller for hybrid electric vehicle (pp. 72 80) sukkur iba journal of emerging technologies sjet | volume 1 no. 1 january – june 2018 © sukkur iba university 75 table i. electric motor parameters. 3.2. model (equation of motion) 3.2.1 traction force fz = mg = fz 1+ fz 2 (1) table ii. vehicle parameters. where, 2 1 1 2 , z z l l f mg f mg l l   (2) 3.2.2 longitudinal forces (fx = actual wheel force) , | | , 1, 2 xi xi max zi f f f for i   3.2.3 vehicle’s acceleration 1 2x x d x veh f f f f a m m     (3) 3.2.4 weight transfer due to acceleration 1 1 1 2 ( ) ( ) veh d z g veh d z g l l ma f f f l l l ma f f f l l        (4) 3.3. power train torques 3.3.1 thermal engine torque , loss eng engine eng eng p t t  (5) 3.3.2. electric motor torque 1 , , , ( , ) max elec map motor max elec mot t p p   (11) 3.4 electrical systems modelling 3.4.1. open circuit voltage of battery batt oc batt q v c  (6) 3.4.2. output voltage of battery s:n o components components parameters quantity 1 said internal combustion engine (si) said cylinders 4 said litres 2.2 said peak power 84 kw said mass 250 kg 2 said permanent magnet electric motor (brushless) said peak power 53 kw said peak torque 248 n.m 3 said nimh ovonic battery said capacity 28 ah said number of modules 50 said nominal voltage 6 v/modul e said energy density 48.6 wh/kg said power density 444.4 w/kg 4 said vehicle body said mass 800 kg said wheel radius 0.27 m said veh. drag coeff. 0.48 ns2/ m2 said surf. fric. coeff. 0.3 (wet road) s:no parameter value 1. said imax,mot 475 a 2. said pmax,mot 53 kw 3. said ω max,mot 8000 rpm engr aqsa kk (et al.), design of artificial neural network bases power split controller for hybrid electric vehicle (pp. 72 80) sukkur iba journal of emerging technologies sjet | volume 1 no. 1 january – june 2018 © sukkur iba university 76 ( ) batt output oc batt d q v v r dt   (7) 3.4.3 state of charge oc min max min v v soc v v    (8) where vmin and vmax represent the minimum and maximum allowable voltages of the battery. these minimum and maximum values are used as 250 and 400 v, respectively, compatible with the electric motor used in the simulation model. table iii. ann controller. 4. artifical neural network controller specification for artificial neural network used in this research are given in table iii. 5. implementation of model phev in matlab –simulink following steps take place for the implementation of the model in simulink i. calculation of total torque from the said em and engine ii. using an integrated transfer case (itc) unit model block the distribution of total torque to the rear and front axles. iii. said rear model blocks and said front axles are separated from each other. iv. for appropriate demand calculations the sensor information is passing to the said controller. v. the simulation model contains a driver block, which selects appropriate driver commands (acceleration and braking) given a time-based drive cycle. simulation model block diagram fig. 1. phev model. 6. results and discussion nedc (new european driving cycle) the graphs and result obtained from the nedc driving cycle in order to obtained better said fuel economy by implementing dynamic programming and artificial neural network controller l strategies are discussed below. in table 4 thermal engine vehicle having said average fuel economy ice (start/ stop) mode has 13.89km/l. for hybrid electrical vehicles average fuel economy for dynamic programing controller (dpc) is 20.57 km/l no component specification 1 input layer 1(vehicle speed, engine rpm) 2 output layer 1(2-nodes, split ratio, gear number) 3 hidden layers: 2(each with 55 nodes) 4 activation function rectified linear unit (relu) 5 learning method backward propagation 6 training tool python, (numpy library) 7 implementation tool (matlab-simulink) engr aqsa kk (et al.), design of artificial neural network bases power split controller for hybrid electric vehicle (pp. 72 80) sukkur iba journal of emerging technologies sjet | volume 1 no. 1 january – june 2018 © sukkur iba university 77 and for artificial neural network controller is 19.71 km/l both are higher than thermal engines fuel economy. battery soc compensation supply is 20.73 km/l this increased compensation shows that from its present initial value battery soc has raised final soc becomes 51% whereas 50%. the initial present value. overall dpc improvement and ann is 48.09% and 49.24% respectively.in ann battery soc compensation provided is 19.34 km/l this increased compensation hence the final soc becomes 49.7 % less than the present value 50 %.where as in each option the overall improvement is 41.9% and 39.237%. fig. 2. controller in model. fig. 3. nedc cycle. ftp-75 (federal test procedure) the graphs and result obtained from the ftp-75 driving cycle on said conventional and hybrid both drivetrain in order to obtain improved said fuel economy and less emission are discussed below. table iv. result of nedc. driving cycle = nedc (initial soc: 50%) uni t therm al hybrid ice (start/stop ) dp c ann average fuel economy [km/ l] 13.89 20.5 7 19.71 average fuel economy with battery soc compensati on [km/ l] 13.89 20.7 3 19.34 final battery soc [-] 51 49.7 % difference in each option 48.09 % 41.9 % 49.24 % 39.237 % 0 100 200 300 400 500 600 0 20 40 60 80 100 120 time [sec] v e h ic le v e lo c ity [ k m /h ] engr aqsa kk (et al.), design of artificial neural network bases power split controller for hybrid electric vehicle (pp. 72 80) sukkur iba journal of emerging technologies sjet | volume 1 no. 1 january – june 2018 © sukkur iba university 78 fig. 4. ftp cycle. in table v final result of ftp-75 the said average fuel economy and having ice only start/stop supplied by the base model consisting of thermal engine vehicle is 12.64 km/l. hybrids embedded with dynamic programming based control strategy gives average fuel economy with battery soc compensation is of 18.49 km/l with battery soc is 50%. the net improvement battery soc compensation and in the fuel economy is 46.28% in each. average fuel economy given by the artificial neural network controller is 17.66 km/l battery soc compensation supplied is 17.78 km/l this increased compensation shows that battery soc has raised from its present initial value hence the final soc becomes 49.7 % less than the present value 50 %.where as in each option the overall improvement is 39.71% and 40.664%. us06 driving cycle the graphs and result obtained from the us06 driving cycle are discussed. fig. 5. us06 cycle. us06 driving cycle in table vi, average fuel economy provided by the thermal embedded base model is 13.49 km/l . in hybrid electric vehicle with dpc the average fuel economy provided is 19.61 km/l with final soc of a battery to 52% and with ann controller average fuel economy to 19.79 km/l upgrading final battery soc =52%. table v. result of ftp. improvement in fuel economy in both controller is 45.36% and 46.70% respectively. in dpc battery soc compensation is 19.61 km/l and in said ann controller and said driving cycle = ftp (initial soc: 50%) uni t therm al hybrid ice (start/stop ) dp c ann average fuel economy [km/ l] 12.64 18.4 9 17.66 average fuel economy with battery soc compensati on [km/ l] 12.64 18.4 9 17.78 final battery soc [-] 50 49.7 % difference in each option 46.2 8 % 39.71 % 46.2 8 % 40.664 % 0 200 400 600 800 1000 1200 0 20 40 60 80 100 120 time [sec] v eh ic le v el oc ity [k m /h ] 0 200 400 600 800 1000 1200 1400 1600 1800 2000 0 10 20 30 40 50 60 70 80 90 100 time [sec] v e h ic le v e lo c ity [ k m /h ] engr aqsa kk (et al.), design of artificial neural network bases power split controller for hybrid electric vehicle (pp. 72 80) sukkur iba journal of emerging technologies sjet | volume 1 no. 1 january – june 2018 © sukkur iba university 79 battery soc compensation to 18.88 km/l, the improvement in compensation of soc battery is 45.36% and 39.95% respectively with both controllers. average fuel economy given by the artificial neural network controller is 17.66 km/l higher than said fuel economy provided by thermal engines. battery soc compensation provided is 17.78 km/l this boost compensation shows that battery soc has raised from its present table vi. result of us06. initial value hence the final soc becomes 49.7 % less than the present value 50 %.where as in each option the overall improvement is 39.71% and 40.664%. for study of us06 driving cycle in table iv, 50% soc of a battery. average fuel economy provided by the thermal embedded base model is 13.49 km/l. in case of dynamic programing hev, the average fuel economy provided is 19.61 km/l and average fuel economy with battery soc compensation is 19.61 km/l., 50% final battery soc, the net productivity for both fuel economy and soc compensation of battery is 45.36%. 7. conclusion the results of simulated phev are follows: an online artificial neural network based power split controller was implemented within hybrid vehicle fuel consumption model. the ann optimization was achieved used the data from dynamic programming based offline controller. the ann controller offers promising results as seen from the tabular data above. the proposed ann controller slightly deviates in terms of consumption figures due to under-fitting. ann control has also been found to have proper gear shifting during the simulation test runs (i.e. too frequent shifting, as exhibited by many other algorithms such as ecsm, is not observed).battery soc is appropriately maintained and utilized as depicted by results. proposed controller performance need to be further tried and tested for combination of multiple driving cycles. references [1] j. m. miller, “propulsion systems for hybrid vehicles,” london: the institution of electrical engineers, 2004. [2] gao and m. ehsani, “an investigation of battery technologies for the army’s hybrid vehicle application,” in proc. of the ieee 56th vehicular technology conference, 2002. [3] m. ehsani, y. gao, s. e. gay, and a. emadi, “modern electric, hybrid electric, and fuel cell vehicles”: driving cycle: us06 (initial soc: 50%) unit therma l hybrid ice (start/stop) dpc an n average fuel economy [km/l ] 13.49 19.6 1 19.7 9 average fuel economy with battery soc compensatio n [km/l ] 13.49 19.6 1 18.8 8 final battery soc [-] 50 52 % difference in each option 45.3 6 % 46.7 0 % 45.3 6 % 39.9 5 % engr aqsa kk (et al.), design of artificial neural network bases power split controller for hybrid electric vehicle (pp. 72 80) sukkur iba journal of emerging technologies sjet | volume 1 no. 1 january – june 2018 © sukkur iba university 80 fundamentals, theory, and design, boca raton: crc press, 2005. [4] gheorghe livinţ, et al, “control of hybrid electrical vehicles.” technical university of aşi romania,2011. [5] vivek yadav mr. manish kashyap, “neural networks and their application” http://seminarprojecttopics.blogspot.co m/2012/07/neural-networks.html, 21 ,april , 2011. [6] artificial neural network seminar report, [accessed: 29 june, 2016]. [7] chan, c.c “the state of the art of electric ,hybrid and fuel cell vehicles”, proceedings of the ieee (vol: 95, issue: 4), 2007 [8] t. hofman, m. steinbuch, r.m. van druten, and a.f.a. serrarens “rulebased equivalent fuel consumptionminimization strategies for hybrid vehicles”, technische universiteit eindhoven, dept. of mech. eng., control systems technology [9] cristian musardo, giorgio rizzoni, fellow, ieee and benedetto staccia, “aecms: an adaptive algorithm for hybrid electric vehicle energy management”, proceedings of the 44th ieee conference on decision and control,2005. [10] jihun hana, young jin parak, dongsuk kumb, “optimal adaptation of equivalent factor of equivalent consumption minimization strategy for fuel cell hybrid electric vehicles under active state inequality constraints ”, vol 267, 2014. [11] jinming liu and huei peng, “modeling and control of a power-split hybrid vehicle”, control systems technology , ieee transactions on (vol:16 , issue: 6), 2008. http://seminarprojecttopics.blogspot.com/2012/07/neural-networks.html http://seminarprojecttopics.blogspot.com/2012/07/neural-networks.html an energy efficient crypto suit for secure underwater sensor communication using genetic algorithm vol. 5, no. 1 | january – june 2022 sjet | p-issn: 2616-7069 |e-issn: 2617-3115 | vol. 5 no. 1 january – june 2022 32 mno2@co3o4 nanocomposite based electrocatalyst for effective oxygen evolution reaction muhammad yameen solangi1, abdul hanan samo2, abdul jaleel laghari1, umair aftab1, rehan ali qureshi1, muhammad ishaque abro1 muhammad imran irfan3 abstract: for large-scale energy applications, conceiving low-cost and simple earth-abundant electrocatalysts are more difficult to develop. by using an aqueous chemical technique, mno2 was added into co3o4 with varying concentrations to prepare mno2@co3o4 nanocomposite (cm). in an aqueous solution of 1 m koh, the electrocatalyst with a greater concentration of mno2 outperforms in terms of oer. to confirm the composition, crystalline structure, and morphology of the electrocatalyst, analytical methods such as x-ray diffraction (xrd) techniques, fourier transformed infrared spectroscopy (ftir) and scanning electron microscopy (sem) were used. at 20 ma/cm2 current density, the electrocatalyst had a lowest overpotential of 310 mv verses reversible hydrogen electrode (rhe). the cm-0.4 electrocatalyst has a small tafel slope value and charge transfer resistance of approximately 72 mv/dec and 74 ω which confirm its high catalytic activity. the electrocatalyst reveals a double layer capacitance (rct) of 18 µf/cm2 and an electrochemical active surface area (ecsa) of 450 cm2, demonstrating that addition of mno2 impurities into co3o4 enhances the active catalyst sites. these findings contribute to the knowledge of these kind of catalysts, that will assist in the development of novel electrocatalysts which are feasible for prospective energy generation technologies. keywords: electrocatalyst; oxygen evolution reaction; cobalt oxide; manganese oxide; alkaline media. 1. introduction growing energy consumption and the depletion of fossil fuels are two major challenges which have led to the discovery of earth abundant alternative sources and the development of effective energy storage systems [1-3]. for this fact, electrochemical water electrolysis is one of the most efficient methods to obtain hydrogen [4,5]. herein, hydrogen evolution reaction (her) takes place at the cathode while oxygen evolution reaction (oer) happens at the anode 1dept. of metallurgy & materials engineering, muet, jamshoro, pakistan. 2college of materials & chemical engineering, harbin engineering university, harbin, china. 3institute of chemistry, university of sargodha, sargodha40100 pakistan corresponding author: yameen.engineer14@gmail.com in an electrochemical water splitting mechanism. nevertheless, the efficient electrocatalysts were utilized for effective water splitting [6-8]. currently, the ruo2/iro2 based noble electrocatalysts have superiority for oer with lower low overpotential value for higher electrocatalytical activity [9,10]. however, they are rare in nature and massive cost electrocatalyst that restrict the usage in industrial applications. to achieve cost-effective hydrogen generation, creating an electro-catalyst for water splitting that are mailto:yameen.engineer14@gmail.com mno2@co3o4 nanocomposite based electrocatalyst for effective oxygen evolution reaction (pp. 32 40) sukkur iba journal of emerging technologies sjet | vol. 5 no. 1 january – june 2022 33 efficient, inexpensive, earth-abundant, stable, and operate at low overpotential is critical [1113]. the oer mechanism contains 4 electron charge transfer kinetics [14]. therefore, oer mechanism is slow process as compared to her and responsible for overall performance of water splitting. in this regard, oer requires more overpotential for water oxidation which provide the major hindrance in water splitting technology [15-17]. so that, researchers are developing electrocatalysts for oer with low overpotential, ease of synthesis and low-cost. in this fact, various transition metal oxides, sulfides, selenides, and phosphide based electrocatalysts were developed to overcome such problems [18-20]. in this work, the impurity addition strategy was applied to create nanocomposite for essential oer performance. wherein, mno2 as an impurity was added in co3o4 to create oxygen vacancies in the co3o4 nanostructures which may be responsible for increase in active sites and decrease the overpotential of catalyst that leads to superior oer performance. the synthesized nanocomposite was characterized by xrd, ftir, sem and electrochemical analysis for the determination of crystallinity, phase purity, morphology, and electrochemical investigation respectively. 2. experimental work 2.1 materials and methods cobalt chloride hexahydrate (cocl2.6.h2o), urea (ch₄n₂o) and potassium permanganate (kmno4) were brought from sigma aldrich, karachi, pakistan. the synthesis of mno2@co3o4 nanocomposite was developed by aqueous chemical method [21]. herein, 0.1m solution of cocl2.6.h2o and ch₄n₂o was added into 100 ml deionized water. after that, kmno4 with two different concentrations i.e., 0.2 g and 0.4 g were added separately in different breakers containing cobalt oxide precursor. these samples were labeled as co3o4 pristine, cm-0.2 and cm-0.4. the label cm denotes the composite of mno2@co3o4. these samples were mixed properly and placed into an electric oven at 95oc for 5 h. once the reaction time was completed then samples were taken out from oven and washed multiple times with deionized (di) water to remove the extra impurities. after that, nanocomposite material was collected through sedimentation method in china dish and dried in oven at 100oc for moisture content removal. the dried samples were placed into furnace for calcination to convert hydroxide phase into oxide phase at 500oc for 5 h. when the calcination time finished then sample were taken from furnace and nanocomposite was achieved for further characterization. 2.2 physical characterization powder x-ray diffraction (xrd) was performed on a philips pan analytical powder x-ray diffractometer at 45 kv and 45 ma using cu kα radiation (λ = 0.15406 nm). the lattice parameters were calculated by bragg’s law in cubic formula. 𝑑(ℎ𝑘𝑙) = 𝑎 √ℎ2 + 𝑘2 + 𝑙2 whereas, “d(hkl)” is the atomic planer spacing, “a” is lattice constant and “(h,k,l)” is the diffracted plane. the crystallite size of sample was computed by debye’s scherrer equation at (311) plane. 𝐷 = 𝑘𝜆 𝛽𝐶𝑜𝑠𝜃 where “d” is the crystallite size (å), “k” is scherrer constant that is equal to 0.9, “λ” is the wavelength of source cukα, “β” is the full width at half maximum (radians) and “θ” is the peak position (radians). fourier transform infrared spectroscopy (ftir) was obtained on a perkin elmer ftir spectrometer spectrum two. scanning electron microscopy (sem) images were achieved on jsm-6380l jeol scanning electron microscope. 2.3 electrochemical analysis electrochemical measurements were carried out on a versastat 4-500 potentiostat consisting of a three-electrode assembly i.e., working electrode, reference mno2@co3o4 nanocomposite based electrocatalyst for effective oxygen evolution reaction (pp. 32 40) sukkur iba journal of emerging technologies sjet | vol. 5 no. 1 january – june 2022 34 electrode and counter electrode made up of glassy carbon electrode, silver-silver chloride electrode and pt wire respectively. glassy carbon electrodes were modified with the electrocatalyst, and various experiments were performed in 1m koh solution. the linear sweep voltammetry (lsv) was done to determine the polarization curves at a scan rate of 5 mv/s and cyclic voltammetry (cv) was used to investigate the effective active surface area at 10, 20 and 30 mv/s scan rates. the chrono-potentiometric analysis was accomplished for durability as synthesized electrocatalyst at 20 ma/cm2 for 40 h. 3. results and discussion 3.1 physical characterization the xrd spectrum of pristine co3o4, cm-0.2 and cm-0.4 can be seen in fig.1. the xrd spectra of pristine co3o4 resembled with jcpds card no. 01-080-1536. the diffraction pattern revealed at the planes of (111), (220), (311), (222), (400), (331), (422), (511), (440), (531), (442), (620), (533) and (622) at the 2 theta angles of 18.848o, 31.017o, 36.461o, 38.231o, 44.436o, 48.669o, 55.177o, 58.842o, 64.656o, 68.011o, 69.111o, 73.437o, 76.618o and 77.668o respectively. this jcpds card validates that the co3o4 has cubic crystalline structure [22,23]. whereas xrd spectrum of mno2 are matched with jcpds card no. 00-044-0992 that diffracted at 2θ values of 19.112o, 37.121o, 38.958o, 45.068o, 49.498o, 59.599o, 65.703o and 69.583o corresponded at the planes (111), (311), (222), (400), (331), (511), (531) and (440). which revealed that mno2 is also in cubic crystalline phase. in addition, other structural features such atomic planer spacing, lattice constant and crystallite size of samples are given in the table 1. the lattice constant of pristine co3o4 is higher but the addition of mno2 reduces its lattice constant that leads to reduction in crystallite size. here, the substitution of large co2+ atom (0.72 å) with small mn4+ atom (0.67 å) carried out that may be responsible for shrinkage of unit cell and achieved reduction in the lattice constant. however, the major peak of co3o4 at (311) diffracted plane shifted toward right side as the concentration of mno2 increases as shown in fig 1(b) which also suggested the substitution of co atom by mn atom. therefore, crystallite size of composite decreases as the concentration of mno2 increases [24,25]. fig. 1. (a) xrd pattern of various samples (b) zoom in view of xrd peak shift the ftir spectra of various samples are shown in fig. 2. it represented that pristine co3o4, cm-0.2 and cm-0.4 involved same peak of o-h, c-h, c=o, o-h, c-o and c=c corresponding to 3438 cm-1, 2927cm-1, 1797cm-1, 1035 cm-1 and 878 cm-1. these organic bonds achieved from the potassium bromide (kbr) that were used for the making the pallet of kbr and sample for ftir measurement. despite this, the main difference was observed in pristine co3o4 and nanocomposite (cm-0.4) of metal oxide m-o peaks which represent o-co-o at 570 cm-1 and co-o at 663 cm-1. however, the presence mno2@co3o4 nanocomposite based electrocatalyst for effective oxygen evolution reaction (pp. 32 40) sukkur iba journal of emerging technologies sjet | vol. 5 no. 1 january – june 2022 35 of mno2 in co3o4 nanostructures sharpen the metal oxide peaks due to the addition of mno2 impurities [22,26,27]. fig. 2. ftir spectra of different samples fig. 3. sem images of (a) pristine co3o4 (b) cm-0.2 (c) cm-0.4 the morphology of prepared co3o4 pristine and nanocomposites was examined by scanning electron microscopy (sem). the sem images of samples are shown in fig. 3. the morphology of pristine co3o4 showed nano needles like structure as shown in fig. 3(a) while the morphology of cm-0.2 and cm-0.4 contained nano flakes in the matrix of nano needles like structure as shown in fig. 3(b, c). it can be seen that cm-0.2 nanocomposite contained fewer nano flakes than cm-0.4. which stated that as the amount of mno2 increase then nano flakes concentration increases in nano needle matrix. 3.2 electrochemical analysis the electrochemical analysis of various samples was investigated in 1m koh environment. the lsv polarization curves can be seen in fig. 4(a) that shows cm-0.4 has lowest overpotential of 310 mv as compare to the overpotential of pristine co3o4 and cm0.2 as 430 mv and 350 mv vs rhe at the current density of 20 ma/cm2. the cm-0.4 electrocatalyst exhibits high oer performance due to lowest overpotential as compare to updated electrocatalyst that can be seen in table 3. the tafel values were obtained by linear fit region of polarization curves as shown in fig. 4(b). the tafel values of pristine co3o4, cm-0.2 and cm-0.4 are calculated as 102 mv/dec, 86 mv/dec and 72 mv/dec respectively. the oxygen evolution reaction (oer) takes place through four electron transfer mechanism which is given as under. 1. m + oh− → moh + e− 2. moh + oh− → mo− + h2o 3. mo− → mo + e− 4. 2𝑀𝑂 → 2m + o2 +2𝑒 − the oer kinetic and theoretical tafel values in alkaline media of 1, 2, 3 and 4 sub reactions are 120 mv/dec, 60 mv/dec, 40 mv/dec and 15 mv/dec respectively [28, 29]. therefore, the current study contains 72 mv/dec tafel value of best composite which suggest that step-1 is rate determining step for effective oer performance. mno2@co3o4 nanocomposite based electrocatalyst for effective oxygen evolution reaction (pp. 32 40) sukkur iba journal of emerging technologies sjet | vol. 5 no. 1 january – june 2022 36 fig. 4. electrochemical analysis of various electrocatalysts (a) polarization curve (b) tafel plot (c) stability & durability of best sample (d) durability of best electrocatalyst at different current densities. the stability test was performed by measuring lsv before and after chronopotentiometry at 20 ma/cm2. the stability of cm-0.4 illustrated in fig. 4(c) which represented its overpotential did not drop after long operation. furthermore, the durability of cm-0.4 can be seen inside fig. 4(c) which showed that cm-0.4 electrocatalyst is long term durable for 40 h. in addition, durability test was also performed at different current densities i.e., 25 ma/cm2 and 50 ma/cm2 as shown in fig. 4(d). it revealed that the potential does not drop at various current densities which give significant proof of electrocatalyst’s stability. the cyclic voltammetric (cv) experiment was performed at different scan rates on various electrocatalysts as shown in fig. 5. the cyclic voltammetry of cm-0.4 has highest current density that represent its highest catalytical active sites as seen in fig. 5(c). in addition, the double layer capacitance cdl value plots were extracted from cv curves as illustrated in fig. 5(d). the cdl values of pristine co3o4, cm-0.2 and cm-0.2 have been calculated as 3.6 µf/cm2, 7.8 µf/cm2 and 18 µf/cm2. the cm-0.4 electrocatalyst has high double layer capacitance than other as prepared electrocatalysts. the electrochemical active surface area esca was calculated by cdl/cs expression, whereas specific capacitance of the electrolyte (cs) in 1m koh is about 0.04 [30]. the electrochemical active surface area (ecsa) was calculated as 450 cm2, 195 cm2, and 90 cm2 for cm-0.4, cm-0.2 and pristine co3o4 respectively which are mentioned in table 2. this data also authenticates the catalytical performance of cm-0.4. the electrochemical impedance spectroscopy data represented by nyquist plot and bode (1, 2) of various samples are shown in fig. 6. the eis data was fitted via z view software and fitted equivalent circuit is enclosed in fig. 6(a). the solution resistance rs is almost similar to all samples due to similar electrolyte conditions. the charge transfer resistance rct was obtained as 74 ω, 240 ω and 460 ω of cm-0.4, cm-0.2 and pristine co3o4 respectively. the results also mno2@co3o4 nanocomposite based electrocatalyst for effective oxygen evolution reaction (pp. 32 40) sukkur iba journal of emerging technologies sjet | vol. 5 no. 1 january – june 2022 37 validate that the rct of nanocomposite based electrocatalyst is lower than pristine electrocatalyst which facilitates the movement of charge in between anode and cathode via electrolyte. fig. 5. cyclic voltammetry of various electrocatalysts (a) pristine co3o4 (b) cm-0.2 (c) cm-0.4 (d) double layer capacitance (cdl) plot. the bode-1 plot gives the information about gain parameter and phase angle in the range of 0.1hz to 100khz frequency at 1.45v applied potential. the phase angles obtained as pristine co3o4 (50.123o), cm-0.2 (45.537o) and cm-0.4 (31.289o) that confirm the superior activity of cm-0.4 electrocatalyst. furthermore, the bode-2 plot provides the knowledge about maximum oscillation frequency of catalyst. it was noticed that cm0.4 contained least oscillation frequency as compared to other two catalyst. therefore, better adsorption of reactive species on the surface of electrocatalysts is attributed due to greater electron recombination lifetime. from these outcomes, it is suggested that cm-0.4 electrocatalyst can be potential candidate for superior water oxidation reaction. fig. 6. electrochemical impedance spectroscopy data of pristine co3o4, cm-0.2 and cm-0.4 (a) nyquist plot (b) bode plot-1 and (c) bode plot-2 mno2@co3o4 nanocomposite based electrocatalyst for effective oxygen evolution reaction (pp. 32 40) sukkur iba journal of emerging technologies sjet | vol. 5 no. 1 january – june 2022 38 table i. xrd structural features of pristine and composite samples. sample ids (hkl) 2 theta d spacing lattice constant fwhm crystallite size (d) degree å å degree å co3o4 pristine (311) 36.4617 2.4622 8.4118 0.28356 294.96 cm-0.2 (311) 36.470 2.4617 8.4051 0.30115 277.74 cm-0.4 (311) 36.658 2.4495 8.3821 0.60382 138.59 table ii. summary of unique features of presented oer catalysts catalyst calculated from lsv calculated from eis calculated from cv tafel slope charge transfer resistance double layer capacitance double layer capacitance electrochemically active surface area b rct cpedl cdl ecsa mv/dec ω mf (µf/cm2) cm2 co3o4 pristine 102 460 0.04 3.6 90 cm-0.2 86 240 0.31 7.8 195 cm-0.4 72 74 0.37 18 450 table iii. comparison of cm-0.4 composite as oer catalyst with recently reported electrocatalysts. electrocatalyst electrolyte current density overpotential references mno2@co3o4 (cm-0.4) 1 m koh 20 ma/cm 2 310 mv this work mg/co3o4 1 m koh 20 ma/cm 2 320 mv [31] fe3o4/co3o4 1 m koh 10 ma/cm 2 370 mv [13] cose4 1 m koh 10 ma/cm 2 320 mv [32] mn-co phosphide 1 m koh 10 ma/cm2 330 mv [33] nico2s4/rgo 1 m koh 10 ma/cm 2 366 mv [34] coox-n-c/tio2c 1 m koh 10 ma/cm 2 350 mv [35] mno2@co3o4 nanocomposite based electrocatalyst for effective oxygen evolution reaction (pp. 32 40) sukkur iba journal of emerging technologies sjet | vol. 5 no. 1 january – june 2022 39 4. conclusion the summery of present work involves the mno2@co3o4 nanocomposite based electrocatalysts which have been synthesized by aqueous chemical method. the xrd pattern and ftir spectrum validate the synthesis of pristine co3o4 and cm nanocomposite. the cm-0.4 catalyst having morphology of nano flakes in the matrix of nano needles exhibits lowest overpotential of 310 mv at current density of 20 ma/cm2. it also contains low tafel slope value and rct value as 72 mv/dec and 74 ω respectively. this electrocatalyst has expressed higher ecsa of 450 cm2. in addition, it is stable and long-term durable for 40 h that makes it superior for oer activity. data availability statement it is stated that this data is soul property of authors and not taken from any data base. the authors also declare that this data is not published in any other journal. author contribution all authors equally contribute for this work conflict of interest the authors declare no conflict of interest. acknowledgment this research work was accomplished in department of metallurgy and materials engineering and advanced research laboratory, muet, jamshoro, sindh, pakistan. references [1] u. aftab, a. tahira, r. mazzaro, m. i. abro, m. m. baloch, m. willander, et al., "the chemically reduced cuo–co3o4 composite as a highly efficient electrocatalyst for oxygen evolution reaction in alkaline media," catalysis science & technology, vol. 9, pp. 6274-6284, 2019. [2] a. mehboob, s. r. gilani, a. anwar, a. sadiqa, s. akbar, and j. patujo, "nanoscale cobalt-oxide electrocatalyst for efficient oxygen evolution reactions in alkaline electrolyte," journal of applied electrochemistry, vol. 51, pp. 691-702, 2021. [3] p. f. liu, h. yin, h. q. fu, m. y. zu, h. g. yang, and h. zhao, "activation strategies of watersplitting electrocatalysts," journal of materials chemistry a, vol. 8, pp. 10096-10129, 2020. [4] a. tahira, u. aftab, m. y. solangi, a. gradone, v. morandi, s. s. medany, et al., "facile deposition of palladium oxide (pdo) nanoparticles on coni2s4 microstructures towards enhanced oxygen evolution reaction," nanotechnology, 2022. [5] z. h. ibupoto, a. tahira, a. a. shah, u. aftab, m. y. solangi, j. a. leghari, et al., "nico2o4 nanostructures loaded onto pencil graphite rod: an advanced composite material for oxygen evolution reaction," international journal of hydrogen energy, vol. 47, pp. 6650-6665, 2022. [6] a. q. mugheri, a. tahira, u. aftab, a. l. bhatti, r. lal, m. a. bhatti, et al., "chemically coupled cobalt oxide nanosheets decorated onto the surface of multiwall carbon nanotubes for favorable oxygen evolution reaction," journal of nanoscience and nanotechnology, vol. 21, pp. 2660-2667, 2021. [7] b. paul, p. bhanja, s. sharma, y. yamauchi, z. a. alothman, z.-l. wang, et al., "morphologically controlled cobalt oxide nanoparticles for efficient oxygen evolution reaction," journal of colloid and interface science, vol. 582, pp. 322-332, 2021. [8] c. l. i. flores and m. d. l. balela, "electrocatalytic oxygen evolution reaction of hierarchical micro/nanostructured mixed transition cobalt oxide in alkaline medium," journal of solid state electrochemistry, vol. 24, pp. 891-904, 2020. [9] w. h. l. p. d. jaekyung yia, chang hyuck choi (ph.d.), yuri lee (ph.d.), kyung su park (ph.d.), byoung koun min (ph.d.), yun jeong hwang (ph.d.), hyung-suk oh (ph.d., "effect of pt introduced on ru-based electrocatalyst for oxygen evolution activity and stability," electrochemistry communications, vol. 104, p. 106469, 2019. [10] q. shi, c. zhu, d. du, and y. lin, "robust noble metal-based electrocatalysts for oxygen evolution reaction," chem soc rev, vol. 48, pp. 3181-3192, 2019. [11] d. zhao, z. zhuang, x. cao, c. zhang, q. peng, c. chen, et al., "atomic site electrocatalysts for water splitting, oxygen reduction and selective oxidation," chemical society reviews, vol. 49, pp. 2215-2264, 2020. [12] a. tahira, electrochemical water splitting based on metal oxide composite nanostructures vol. 2066. linköping: linköping university electronic press, 2020. [13] a. l. bhatti, u. aftab, a. tahira, m. i. abro, r. h. mari, m. k. samoon, et al., "an efficient and functional fe3o4/co3o4 composite for oxygen evolution reaction," journal of nanoscience and nanotechnology, vol. 21, pp. 2675-2680, 2021. [14] a. hanan, a. j. laghari, m. y. solangi, u. aftab, m. i. abro, d. cao, et al., "cdo/co3o4 mno2@co3o4 nanocomposite based electrocatalyst for effective oxygen evolution reaction (pp. 32 40) sukkur iba journal of emerging technologies sjet | vol. 5 no. 1 january – june 2022 40 nanocomposite as an efficient electrocatalyst for oxygen evolution reaction in alkaline media," international journal of engineering science technologies, vol. 6, pp. 1-10, 2022. [15] y. v. kaneti, y. guo, n. l. w. septiani, m. iqbal, x. jiang, t. takei, et al., "self-templated fabrication of hierarchical hollow manganesecobalt phosphide yolk-shell spheres for enhanced oxygen evolution reaction," chemical engineering journal, vol. 405, p. 126580, 2021. [16] i. m. abdullahi, j. masud, p.-c. ioannou, e. ferentinos, p. kyritsis, and m. nath, "a molecular tetrahedral cobalt–seleno-based complex as an efficient electrocatalyst for water splitting," molecules, vol. 26, p. 945, 2021. [17] a. l. bhatti, u. aftab, a. tahira, m. i. abro, m. kashif samoon, m. h. aghem, et al., "facile doping of nickel into co3o4 nanostructures to make them efficient for catalyzing the oxygen evolution reaction," rsc advances, vol. 10, pp. 1296212969, 2020. [18] c. linder, s. g. rao, a. le febvrier, g. greczynski, r. sjövall, s. munktell, et al., "cobalt thin films as water-recombination electrocatalysts," surface and coatings technology, vol. 404, p. 126643, 2020. [19] a. badreldin, a. e. abusrafa, abdel, and a. wahab, "oxygen-deficient cobalt-based oxides for electrocatalytic water splitting," chemsuschem, vol. 14, pp. 10-32, 2021. [20] a. badruzzaman, a. yuda, a. ashok, and a. kumar, "recent advances in cobalt based heterogeneous catalysts for oxygen evolution reaction," inorganica chimica acta, vol. 511, p. 119854, 2020. [21] m. r. s. a. janjua, "synthesis of co3o4 nano aggregates by co-precipitation method and its catalytic and fuel additive applications," open chemistry, vol. 17, pp. 865-873, 2019. [22] d. d. m. prabaharan, k. sadaiyandi, m. mahendran, and s. sagadevan, "precipitation method and characterization of cobalt oxide nanoparticles," applied physics a, vol. 123, 2017. [23] m. y. solangi, u. aftab, a. tahira, m. i. abro, r. mazarro, v. morandi, et al., "an efficient palladium oxide nanoparticles@co3o4 nanocomposite with low chemisorbed species for enhanced oxygen evolution reaction," international journal of hydrogen energy, vol. 47, pp. 3834-3845, 2022. [24] l. abdelhak, b. amar, b. bedhiaf, d. cherifa, and b. hadj, "characterization of mn-doped co3o4 thin films prepared by sol gel-based dip-coating process," high temperature materials and processes, vol. 38, pp. 237-247, 2019. [25] n. manjula, m. pugalenthi, v. s. nagarethinam, k. usharani, and a. r. balu, "effect of doping concentration on the structural, morphological, optical and electrical properties of mn-doped cdo thin films," materials science-poland, vol. 33, pp. 774-781, 2015. [26] t. athar, a. hakeem, n. topnani, and a. hashmi, "wet synthesis of monodisperse cobalt oxide nanoparticles," isrn materials science, vol. 2012, pp. 1-5, 2012. [27] a. n. naveen and s. selladurai, "investigation on physiochemical properties of mn substituted spinel cobalt oxide for supercapacitor applications," electrochimica acta, vol. 125, pp. 404-414, 2014. [28] u. aftab, a. tahira, r. mazzaro, v. morandi, m. i. abro, m. m. baloch, et al., "facile nico2s4/c nanocomposite: an efficient material for water oxidation," tungsten, vol. 2, pp. 403-410, 2020. [29] a. q. mugheri, a. tahira, u. aftab, m. i. abro, a. b. mallah, g. z. memon, et al., "an advanced and efficient co3o4/c nanocomposite for the oxygen evolution reaction in alkaline media," rsc advances, vol. 9, pp. 34136-34143, 2019. [30] a. tahira, z. h. ibupoto, m. vagin, u. aftab, m. i. abro, m. willander, et al., "an efficient bifunctional electrocatalyst based on a nickel iron layered double hydroxide functionalized co3o4 core shell structure in alkaline media," catalysis science & technology, vol. 9, pp. 2879-2887, 2019. [31] a. h. samo, u. aftab, m. yameen, a. j. laghari, m. ahmed, m. n. lakhan, et al., "magnesium doped cobalt-oxide composite for active oxygen evolution reaction," journal of applied and emerging sciences, vol. 02, pp. 210-216, 2021 [32] i. m. abdullahi, j. masud, p.-c. ioannou, e. ferentinos, p. kyritsis, and m. nath, "a molecular tetrahedral cobalt–seleno-based complex as an efficient electrocatalyst for water splitting," molecules, vol. 26, p. 945, 2021. [33] y. v. kaneti, y. guo, n. l. w. septiani, m. iqbal, x. jiang, t. takei, et al., "self-templated fabrication of hierarchical hollow manganesecobalt phosphide yolk-shell spheres for enhanced oxygen evolution reaction," chemical engineering journal, vol. 405, p. 126580, 2021. [34] c. shuai, z. mo, x. niu, x. yang, g. liu, j. wang, et al., "hierarchical nico2s4 nanosheets grown on graphene to catalyze the oxygen evolution reaction," journal of materials science, vol. 55, pp. 1627-1636, 2020. [35] l. he, j. liu, b. hu, y. liu, b. cui, d. peng, et al., "cobalt oxide doped with titanium dioxide and embedded with carbon nanotubes and graphene-like nanosheets for efficient trifunctional electrocatalyst of hydrogen evolution, oxygen reduction, and oxygen evolution reaction," journal of power sources, vol. 414, pp. 333-344, 2019. format template vol. 4, no. 1 | january – june 2021 sjet | p-issn: 2616-7069 |e-issn: 2617-3115 | vol. 4 no. 1 january – june 2021 12 sequential modeling for the recognition of activities in logistics zafi sherhan syed1, m. z. abbas shah syed1, muhammad shehram shah1, aunsa shah2 abstract: activity recognition is an important task in cyber physical system research and has been the focus of researchers worldwide. this paper presents a method for activity recognition in logistics operations using data from accelerometer and gyroscope sensors. a long short term memory (lstm) recurrent neural network (rnn), bidirectional lstm (bi-lstm) and a convolutional lstm (convlstm) are used to classify between six activities being performed in the logistics operations being carried out. comparing the performance of the lstms to the conv-lstm network, the designed bi-lstm rnn outperforms the other networks considered in this work. this work will aid in the use of sequential modeling approaches for activity recognition in logistics. keywords: accelerometer, gyroscope, lara, logistics activity recognition, sequential modeling 1. introduction activity recognition is an important task for multiple applications, including but not limited to physical therapy [1], games [2], fall detection [3] and other health specific causes as in [4, 5]. with the introduction of the internet of things and the industry 4.0 concept, an interest has developed towards research in to cyber physical systems. such systems allow for the seamless integration of workers into the factory workflow for optimization of industrial processes, thereby increasing industrial productivity. moreover, with increasing automation, robots and humans work together on the factory floor; and recognizing activities in the manufacturing process will allow for this to happen in a smooth manner. furthermore, monitoring workers to look at their movements may also be carried out for various health 1mehran university of engineering & technology, jamshoro, 76090, sindh, pakistan 2university of sindh, jamshoro, 76080, sindh, pakistan corresponding author: zaigham.shah@faculty.muet.edu.pk purposes so as to promote a safer working environment. activities can be recognized using three different modalities, using ambient sensors [6], imaging/video [7] or using movement sensors such as accelerometer, gyroscopes and magnetometers [8]. within these three modalities, the use of inertial measurement units (imus) is the most popular as they tend to not pose limits to movement, are easy to deploy and use and are cheaper in many application scenarios. in an activity recognition system, the imus capture movement data as the subject performs one of several activities to be recognized. this data, after possible suitable processing is sent to a classifier which identifies the activity being performed. even though, activity recognition has been of great interest to researchers due to its many applications, this task is nontrivial since zafi sherhan syed (et al.), sequential modeling for the recognition of activities in logistics (pp. 12 21) sukkur iba journal of emerging technologies sjet | vol. 4 no. 1 january – june 2021 13 the movement patterns for different activities may be very similar, for e.g., walking upstairs or downstairs, jogging or jumping etc. also, the movement patterns might also differ in between the subject themselves which may confuse the classifier algorithm being used. in this regard, deep learning has fostered an era of improved performance of activity recognition algorithms. in this paper, activity recognition has been performed for logistics utilizing deep learning to perform sequential modeling of inertial sensor data. data from the publicly available lara dataset [9] is used which contains accelerometer and gyroscope data for workers performing picking and packing operations typical in logistics. the data gathered from these sensors is used for sequential modeling of these activities in order to differentiate between them. the results indicate that the described method offers promising performance for use in the application of activity recognition in a logistics scenario. the paper is organized as follows, section 2 provides a discussion of the literature search carried out for this work, section 3 gives a brief introduction to the lara dataset, section 4 discusses the methodology for the current work, section 5 presents and discusses the results and a conclusion is provided in section 6 along with directions for future work. 2. literature review as discussed in the previous section, activity recognition has garnered a lot of interest from the research community. we discuss some of the relevant literature in this section. the authors in [10] perform activity classification for order picking using imus. they use three imus for their task, one on the torso and the other two on the worker’s arm. various statistical features are first computed from a windowed version of the data, resulting in a feature vector of size 54. this is then passed on to three classifiers support vector machines (svm), naïve bayes and radom forests (rf) to determine the activity being performed. they find that random forests perform the best for their application. more work by the authors in [11] also target the recognition of activities in an order picking process. they use data from three inertial measurement sensors placed on both wrists and one on the chest. sliding windows are then used to extract segments from each imu and then a convolutional neural network (cnn) [12] is used to determine the activity being performed. in [13], alexander diete et.al. develop a sensor setup for workers in logistics picking operations. they design two devices, one worn on the wrist and the other on the head. the sensors used in these devices are inertial sensors, video and depth, pressure and ultrasonic sensors. the authors collect their own data and use a neural network and a random forest classifier to differetiate between the various intra-activities that are performed in the picking process. in more work from the same authors [14], the authors perform activity recognition for a grabbing operation in an order picking process. they form their dataset based on inertial sensor data as well as video information captured using four different devices. to perform the task, they extract time-frequency domain features from the imu data and color/feature descriptor (histogram of oriented gradients) from the video frames. they are able to achieve an fscore of 85% as the best result when comparing three different ml algorithms, the svm, rf and an artificial neural network (ann). the authors in [15], use convolutional neural networks to perform activity recognition on three datasets, opportunity [16], pamap2 [17] and a dataset from an order picking processes. the authors use a temporal convolutional network, first suggested in [12] where the cnn has parallel temporal convolutional branches for each imu and is called cnn-imu. their cnn-imu consists of four convolutional layers, two pooling layers and two fully connected layers. as a baseline, they compare the performance of their architecture with a typical cnn. segments are extracted from these datasets using a sliding window approach and fed to two variations of the considered networks, it is found that their network performs the best for zafi sherhan syed (et al.), sequential modeling for the recognition of activities in logistics (pp. 12 21) sukkur iba journal of emerging technologies sjet | vol. 4 no. 1 january – june 2021 14 the order picking dataset. they also conclude that max-pooling may not necessarily help in improving network performance. in [18], the authors attempt to perform activity recognition in the industry to assess worker performance. they do this using an accelerometer and a gyroscope placed on a worker’s wrists in the meat processing industry and sending the captured data to a cloud for further processing. they also consider meat throughput and use proximity sensors as well. feature extraction (a total of 86 features) is performed from the raw sensor values and multiple classifiers are used for detecting one of the three activities being performed. they find that random forests perform the best for their application. the authors in [19] deploy a wireless sensor network system for biomechanical overload assessment in a material handling process. the sensing modalities they use are inertial measurement sensors and electromyography sensors and they use a multilayer perceptron network for classification. the authors in [20] utilize an long short term memory (lstm) recurrent neural network to perform activity recognition on the wisdm [21] dataset using accelerometer sensor data for six activities. they achieve an accuracy of over 94% using an lstm network composed of 3 lstm layers consisting of 64 nodes each. the authors in [22] make use of a bidirectional lstm network for performing human activity recognition from accelerometer and gyroscope data that they collected themselves. they consider six activities to classify from, these were walking, walking upstairs, walking downstairs, laying, standing and sitting. they were able to achieve an overall accuracy of 92.67% with the worst performing activity being sitting and the best being laying down. the number of lstm layers and the neurons for each layer are determined through a search grid. their final model was composed of 3 lstm layers with 175 nodes in each layer. the authors in [23] use a hierarchical lstm (h-lstm) model to perform activity recognition using accelerometer sensor data. they use the model to perform activity recognition on the human activity recognition using smartphones dataset [24] and the heterogeneity human activity recognition (hhar) [25] dataset. data from the sensor is first denoised and then feature computation (various time-frequency domain features) is performed before being passed on the h-lstm. the h-lstm model is made up of two lstm layers followed by a softmax classifier. they are able to achieve an accuracy of 99.65% (best result) for this task, which when compared to their baselines, established using a random forest and decision tree classifier is much higher. the authors in [26] compare the performance of traditional machine learning (tdl) methods against deep learning methods for recognizing human activities using imus. a comparison of svm, k-nearest neighbours, rf, rnn and cnn is provided for two different datasets, wisdm and uschad [27]. from their experiments, they are able to get an accuracy of 90% for deep learning methods and 87% for tdl methods. as can be observed from the literature, while there have been several approaches towards performing activity recognition in logistics, work in this domain is still ongoing. to contribute to this body of knowledge, we make use of deep learning based sequential modeling approaches to perform activity recognition. 3. lara dataset the logistics activity recognition challenge (lara) dataset was developed by the innovationlab hybrid services in logistics at tu dortmund university and consists of recorded data for two picking operations and one packing operation performed by fourteen different subjects. each subject is recorded by three means, an omocap system which tracks markers on the workers suit and provides movement measurements as coordinates, the second modality are six imus capturing acceleration and gyroscopic information placed on the persons waist, legs and arms and their chest and the third is video recordings. the recording of the imus was performed with a sampling frequency of 100hz and eight activity classes were labeled for multiple trials. zafi sherhan syed (et al.), sequential modeling for the recognition of activities in logistics (pp. 12 21) sukkur iba journal of emerging technologies sjet | vol. 4 no. 1 january – june 2021 15 these activity classes are standing, walking, cart, handling (upwards), handling (centered), handling (downwards), synchronization and none. in this work, the last two activity classes are not considered as they are not a choreographed part of the dataset’s logistics scenario, synchronization referred to a waving motion at the start of each recording and the class none consisted of unrecognizable parts of the recordings. 4. methodology the process of sequential modeling of inertial sensor data for the recognition of activities in logistics follows a two-step methodology. the first is the extraction of segments from the recordings present in the dataset and the next is the use of deep learning architectures to determine the activity being performed. in this section we brief on both steps of the process. 4.1. windowing the recordings of the activities contain activity annotations for each signal measurement (sample) captured by the sensors. however, in order to train a deep learning algorithm, it is required that activity samples be sent that characterize a movement pattern associated with the activity being performed. in order to extract samples (at the activity level), that make up the picking/packing operations being performed by workers in the lara dataset, the imu recordings are windowed in to segments of duration one second with an overlap of 75%. however, since the segments are drawn continuously, the segments contain sensor measurements which belong to multiple different activities. to establish a single label to every segment, we make use of majority voting as the labeling scheme. a similar method has been used by authors previously performing continuous segmentation of activity signals from imus [15]. 4.2. classification sequential modeling for activity recognition in this work makes use of two algorithms, these have been based on their popularity for activity recognition. sequential modeling using deep architectures is mostly reliant on recurrent neural networks (rnn). instead of looking at the patterns in the spatial domain as performed by deep neural networks and convolutional neural networks, rnns also aim to make use of sequential information (time in the case of activity recognition) to better understand the input before producing the output. this sequential learning capability has made rnns quite useful in applications such as language translation [28], time series prediction [29], speech recognition [30] and more. however, vanilla rnns suffer from vanishing gradients which hampers the training of such networks. long short term memory networks are a slightly modified class of rnns which avoid this problem. an lstm cell is shown in fig. 1. in the figure, xt is the input and ht is the current output. an lstm network is formed by multiple lstm cells connected together. in this work, the first network used for sequential modeling is a stacked lstm. a three-layer lstm network is used for this purpose which is followed by one dense layer with a softmax to indicate to one of the six output classes. each of the lstm layers is made up of 100 units and the first two lstm layers are followed by a drop out layer. the second network used is a bidirectional lstm network with identical network parameters as the first simple lstm network. a bidirectional lstm can learn from input data in both directions and therefore has the potential to capture a better representation of the data being fed to it. in addition to this, two variants of these networks have been tested, one with an extra dense layer of size 60 with a relu activation function after the lstm/bidirectional lstm layers. this was done in an attempt to get a better representation of the output lstm features before sending them to the softmax layer for classification. for the remainder of the discussion, the stacked lstm with one dense layer is denoted as stacked lstm-1 and the stacked lstm with two dense layers is denoted as stacked lstm-2. similarly, the stacked bidirectional lstm with one dense layer is denoted as stacked bi-lstm-1 and the stacked bidirectional lstm with two dense layers is denoted as stacked bi-lstm zafi sherhan syed (et al.), sequential modeling for the recognition of activities in logistics (pp. 12 21) sukkur iba journal of emerging technologies sjet | vol. 4 no. 1 january – june 2021 16 2. the networks are shown in fig. 2. one of the dense layers is shown with a dotted border to indicate its absence in the specific network variants. the other network used for time modeling of the activities is a convlstm network. the convlstm network is used as it has shown promising performance for activity recognition tasks [31] and that this network can make use of convolutional filters to better extract features compared to normal lstm nodes. the convlstm network used in this work consists of two convlstm layers followed by one dense layer. each of the convlstm layers uses 64 filters and are followed by a dropout layer before the output is flattened prior to the dense layer. the dense layer consists of six neurons and uses a softmax activation function. similar to the experiment with stacked lstms, an experiment was also fig. 1. lstm cell table 1. parameters for the architectures used for classification stacked lstm / bilstm convlstm lstm layers 3 conv2d layers 2 lstm layer size 100 filters 64 dense layers 1/2 dense layers 1/2 dense layer size 6/60 and 6 dense layer size 6/60 and 6 fig. 2. stacked bi-lstm/ lstm network conducted for the convlstm with an extra dense layer before the classification layer, the size of the layer was 60 utilizing a relu activation function. the first convlstm network with only one dense layer is referred to as convlstm-1 and the convlstm network with two dense layers is referred to as convlstm-2. the convlstm networks used are shown in fig. 3, a dotted dense layer is shown to indicate its absence in one of the experiments. the details of all these networks are summarized in table. 1. zafi sherhan syed (et al.), sequential modeling for the recognition of activities in logistics (pp. 12 21) sukkur iba journal of emerging technologies sjet | vol. 4 no. 1 january – june 2021 17 fig. 3. convlstm network 5. experiments two experiments were performed, one with using the stacked lstm networks and the other using the convlstm network. in both cases, the data was normalized for each sensor and split in to three sets for training, validation and testing. moreover, a learning rate of 10e-6 with an adam optimizer was used during the training process and the networks were trained for 50 epochs with early stopping used to determine the best model before overfitting starts. a batch size of 400 was used for these experiments. results for the experiments have been reported using the f1 score. 5.1. stacked lstms / bidirectional lstms in this experiment, the stacked lstm network was trained using the segmented activity data. early stopping was used for training all four lstm networks considered in this work attempting to minimize the unweighted average recall (uar). table. 2 lists the epochs for each of the networks to complete training. moreover, the train and validation loss for each epoch of the training are shown in fig. 4 fig. 7 for the stacked lstms / bi-lstms networks respectively. table 2. number of epochs for training each lstm/bi-lstm network epochs stacked lstm-1 49 stacked lstm-2 47 stacked bi-lstm-1 49 stacked bi-lstm-2 48 fig. 4. training loss for stacked lstm-1 fig. 5. training loss for stacked lstm-2 zafi sherhan syed (et al.), sequential modeling for the recognition of activities in logistics (pp. 12 21) sukkur iba journal of emerging technologies sjet | vol. 4 no. 1 january – june 2021 18 fig. 6. training loss for stacked bilstm-1 fig. 7. training loss for stacked bilstm-2 moreover, the results for activity recognition from this experiment have been shown in table. 3. the best results have been shown in bold. the test set uars for the networks were 84.64%, 84.63%, 86.30% and 87.04% for stacked lstm-1, stacked lstm2, stacked bi-lstm-1 and stacked bi-lstm2 respectively. it can be observed from table. 3 that the stacked bi-lstm-2 (i.e. with an extra fully connected layer before the classification stage) performs the best overall among the considered lstm architectures. the stacked lstm-2 (with an extra dense layer) matches the best performing model for the cart activity. the worst performing activity was the stand with the best f1 score of 77%. the best recognized activities were handling centered and cart with an f1 score of 93%. also, one can note that the addition of an extra dense layer does not provide a performance improvement in the case of stacked lstms as opposed to stacked bi-lstms. as far as training is concerned, all four networks do not differ much in the number of epochs required to converge to the best model and the train/validation loss final values are similar as well. 5.2. convlstms for this experiment, two stacked convlstm networks were trained which consisted of two convlstm layers and one dense layer for one experiment with an extra dense layer added to for the second one. early stopping was used for training both stacked convlstm networks considered. the epochs for which each networks’ training stopped before overfitting occurred are presented in table. 4 and training loss plots in fig. 8 and fig. 9. the test uars for the convlstm-1 and convlstm-2 were 72.24% and 72.22% respectively. the results for activity recognition from this experiment have been shown in table. 5. the best results have been shown in bold. table 3. f1 scores for stacked lstm/bi-lstm activity stacked lstm-1 stacked lstm-2 stacked bilstm-1 stacked bilstm-2 f1 (%) f1 (%) f1 (%) f1 (%) stand 72 71 76 77 walking 83 82 85 85 cart 91 93 92 93 handling upwards 80 78 81 83 handling centered 92 91 92 93 handling downwards 83 83 85 87 zafi sherhan syed (et al.), sequential modeling for the recognition of activities in logistics (pp. 12 21) sukkur iba journal of emerging technologies sjet | vol. 4 no. 1 january – june 2021 19 table 4. number of epochs for training each convlstm network epochs stacked convlstm-1 43 stacked convlstm-2 49 fig. 9. training loss for convlstm-1 fig. 10. training loss for convlstm-2 it can be observed from table. 5 that both the convlstm networks have performed nearly equally well. the worst recognized activity, as in the previous experiments, in this case is also stand. the best recognized activity is handling centered as was similar in the experiments of the last section. when comparing all the experiments performed, it can be observed that the stacked lstms in general have performed much better than the stacked convlstm which indicates that the convolutional filters present in the stacked convlstm architecture were not beneficial towards sequential modeling of the activities in the scenario considered. among all the models experimented with, stacked bi directional lstms with only one dense layer (classification layer) was found to provide the best results. in order to better understand the performance of this model, the f1 score, precision and recall for each of the activities have been shown in table 6. looking at the detailed performance numbers, one can see that the activities stand and handling upwards are the worst recognized activities while handling centered, cart are the best recognized activities. 6. conclusion in this paper, activity recognition has been performed for a logistics scenario by using sequential modeling approaches. to achieve this, three networks have been used, stacked lstms, stacked bidirectional lstms and stacked convlstms. moreover, two variants of each of these networks have been utilized. after extracting segments of activity data captured using inertial measurement sensors with sliding windows, the activity data is sent to these three networks for recognition purposes. it was found that, from the networks considered, stacked bidirectional lstm with two dense layers performs the best. the most poorly recognized activity was stand whereas the best recognized activity was handling centered. moreover, from the experiments with stacked convlstm architectures, it was determined that with the given experimental settings, the table 5. f1 scores for convlstm activity stacked convlstm1 stacked convlstm2 f1 (%) f1 (%) stand 49 48 walking 74 73 cart 86 87 handling upwards 64 64 handling centered 86 86 handling downwards 77 77 zafi sherhan syed (et al.), sequential modeling for the recognition of activities in logistics (pp. 12 21) sukkur iba journal of emerging technologies sjet | vol. 4 no. 1 january – june 2021 20 table 6. f1 score, precision, recall for best performing model activity best performing network (stacked bi-lstm-2) f1 (%) precision (%) recall (%) stand 77 76 77 walking 85 86 84 cart 93 90 96 handling upwards 83 80 86 handling centered 93 94 92 handling downwards 87 87 87 convolutional features extracted by the convlstm did not result in better performance compared to a stacked simple lstm. this work serves as a basis for further research in the sequential learning for activity recognition in logistics. further work in his area would be the use of attention mechanisms within the sequential learning scheme, investigating importance of sensors and crossdataset performance analysis. author contribution all authors contributed equally to the work. data availabilty statement the dataset used during the current study is publicly available at logistic activity recognition challenge (lara) a motion capture and inertial measurement dataset [https://zenodo.org/record/3862782#.yhtldj 8pbqm]. conflict of interest the authors declare no conflict of interest. funding not applicable. acknowledgment not applicable. references [1] l. billiet, t. swinnen, r. westhovens, k. de vlam and s. van huffel, activity recognition for physical therapy: fusing signal processing features and movement patterns. in proceedings of the 3rd international workshop on sensor-based activity recognition and interaction, 2016, p. 1-6 [2] a. almeida and a. alves, activity recognition for movement-based interaction in mobile games. in proceedings of the 19th international conference on human-computer interaction with mobile devices and services, 2017, p. 1-8. [3] a. chelli and m. pätzold, a machine learning approach for fall detection and daily living activity recognition, ieee access, 7, 2019, p. 38670-38687. [4] wei-yi cheng, a. scotland, f. lipsmeier, t. kilchenmann, l. jin, jens schjodt-eriksen, d. wolf et al. human activity recognition from sensor-based large-scale continuous monitoring of parkinson’s disease patients, in 2017 ieee/acm international conference on connected health: applications, systems and engineering technologies (chase), 2017, p. 249-250 [5] k. j. kim, n. m. hassan, s. h. na and e. n. huh, dementia wandering detection and activity recognition algorithm using tri-axial accelerometer sensors. in proceedings of the 4th international conference on ubiquitous information technologies & applications, 2009, p. 1-5 [6] d. singh, e. merdivan, i. psychoula, j. kropf, s. hanke, m. geist and a. holzinger, human activity recognition using recurrent neural networks. in international cross-domain conference for machine learning and knowledge extraction, 2017, p. 267-274 [7] t. dobhal, v. shitole, g. thomas and g. navada, human activity recognition using binary motion image and deep learning. procedia computer science, 58, 2015, p. 178-185. [8] w. sousa lima, e. souto, k. el-khatib, r. jalali and j. gama, human activity recognition using inertial sensors in a smartphone: an overview. sensors, 19(14),2019, p. 3213. [9] f. niemann, c. reining, f. m. rueda, n. r. nair, j. a. steffens, g. a. fink and m. t. hompel, lara: creating a dataset for human activity recognition in logistics using semantic attributes. sensors, 20(15), 2020, p. 4083. [10] s. feldhorst, m. masoudenijad, m. ten hompel and g. fink, motion classification for analyzing the order picking process using mobile sensors. in proc. int. conf. pattern recognition applications and methods, 2016, p. 706-713. [11] r. grzeszick, j. m. lenk, f. m. rueda, g. a. fink, s. feldhorst, and m. ten hompel, deep neural network based human activity recognition for the order picking process. acm international conference proceeding series, part f1319. 2017 zafi sherhan syed (et al.), sequential modeling for the recognition of activities in logistics (pp. 12 21) sukkur iba journal of emerging technologies sjet | vol. 4 no. 1 january – june 2021 21 [12] yang, m. n. nguyen, p. p. san, x. li and s. krishnaswamy, s, deep convolutional neural networks on multichannel time series for human activity recognition. ijcai, 15, 2013, p. 3995–4001. [13] a. diete, l. weiland, t. sztyler, and h. stuckenschmidt, exploring a multi-sensor picking process in the future warehouse. proceedings of the 2016 acm international joint conference on pervasive and ubiquitous computing: adjunct, 2016, p. 1755–1758. [14] a. diete, t. sztyler, l. weiland and h. stuckenschmidt recognizing grabbing actions from inertial and video sensor data in a warehouse scenario, 14th international conference on mobile systems and pervasive computing, 2017, p. 16–23. [15] f. moya rueda, r. grzeszick, g. a. fink, s. feldhorst and m. ten hompel, convolutional neural networks for human activity recognition using body-worn sensors. informatics, 5(2), 2018, p. 26. [16] r. chavarriaga, h., sagha, a. calatroni, s. t. digumarti, g. tröster, j. d. r. millán and d. roggen, d, the opportunity challenge: a benchmark database for on-body sensor-based activity recognition. pattern recognition letters, 34(15), 2013, p. 2033-2042. [17] pamap2 physical activity monitoring data set. available online: http://archive.ics.uci.edu/ml/datasets/ pamap2+physical+activity+monitoring (accessed: 25 march 2021). [18] a. r. m. forkan, f. montori, d. georgakopoulos, p. p. jayaraman, a.yavari and a. morshed, an industrial iot solution for evaluating workers’ performance via activity recognition. 2019 ieee 39th international conference on distributed computing systems (icdcs), 2019, p. 1393–1403. [19] p. giannini, g. bassani, c. a. avizzano and a. filippeschi, wearable sensor network for biomechanical overload assessment in manual material handling. sensors, 20(14), 2020, p. 3877 [20] s. w. pienaar and r. malekian, human activity recognition using lstm-rnn deep neural network architecture. in 2019 ieee 2nd wireless africa conference (wac), 2019, p. 1-5 [21] wisdm lab: dataset. available online: www.cis.fordham.edu/wisdm/dataset.php#actitrack er (accessed: 25 march 2021). [22] f. hernández, l. f.suárez, j. villamizar and m. altuve, human activity recognition on smartphones using a bidirectional lstm network. in 2019 xxii symposium on image, signal processing and artificial vision (stsiva), 2019, p. 1-5 [23] l. wang and r. liu, human activity recognition based on wearable sensor using hierarchical deep lstm networks, circuits, systems, and signal processing, 39(2), 2020, p. 837-856. [24] j. l. reyes-ortiz, d. anguita, a. ghio and x. parra, human activity recognition using smartphones data set, uci machine learning repository; university of california, irvine, school of information and computer sciences: irvine, ca, usa, 2012 [25] j. l. reyes-ortiz, l. oneto, a. ghio, a. samá, d. anguita and x. parra, human activity recognition on smartphones with awareness of basic activities and postural transitions. in international conference on artificial neural networks, 2014, p. 177-184 [26] c. hou, a study on imu-based human activity recognition using deep learning and traditional machine learning, in 2020 5th international conference on computer and communication systems (icccs) , 2020, p. 225-234 [27] m. zhang and a. a. sawchuk, usc-had: a daily activity dataset for ubiquitous activity recognition using wearable sensors. in proceedings of the 2012 acm conference on ubiquitous computing, 2012, p. 1036-1043. [28] k. cho, b. van merriënboer, c. gulcehre, d. bahdanauf. bougares, h. schwenk and y. bengio, learning phrase representations using rnn encoder-decoder for statistical machine translation. arxiv preprint arxiv:,2014, 1406.1078. [29] z. che, s. purushotham, k. cho, d. sontag and y. liu, recurrent neural networks for multivariate time series with missing values. scientific reports, 8(1), 2018, p. 1-12. [30] y. miao, m. gowayyed and f. metze, f, eesen: end-to-end speech recognition using deep rnn models and wfst-based decoding. in 2015 ieee workshop on automatic speech recognition and understanding (asru), 2015, p. 167-174 [31] zili li, liu yixin, guo xuerong and ji zhang. multi-convlstm neural network for sensor-based human activity recognition, in journal of physics: conference series, 1682(1), 2020, p. 012062. format template vol. 3, no. 1 | january june 2020 sjet | issn: 2616-7069 | vol. 3 | no. 1 | © 2020 sukkur iba university 1` experimental based comparative analysis and characteristics of dc series motor by using different techniques mohsin ali koondhar1, ali asif malak1, masood ali koondhar1, irfan ali channa2 abstract: in this paper, distinct techniques of speed controlling of a direct current (dc) motor and its characteristics are discussed. the direct current (dc) motor has a wide range of speed control, which can be used in robots, drilling, cutting, and household applications due to affordable cost and low complexity of control configuration for speed and torque control. as dc motors are considered as the best type of motors, in view of the speed control and speed regulation, numerous approaches are available to control the motor rotational speed. dc series motor control by using a resistive controller with and without a programmable logic controller (plc) is proposed. the motor voltage can be changed by inserting a resistor in series with dc motor. in this paper, through an experimental work armature resistive drive control technology and motor control plc technology is used to control motor speed. plc is used to control the resistance of the motor, thereby reducing driving voltage to change the speed. the results confirm the authentic efficiency of the proposed method of controlling motor speed. keywords: dc series motor, plc, torque, resistive controller. 1. introduction the dc drives are used in rolling, wine winders, cranes, paper mills, machine tools, printing press, and textile mills, etc. dc motors have irregular essentials and used largely in uncertain speed. dc motor can produce immense origin torque and it is still achievable to gain speed control by the immense range [1]. dc motors have variable characteristics and are used extensively in variable speed drives. dc motor can provide a high starting torque and it is also possible to obtain speed control over a wide range [2]. 1 department of electrical engineering, quaid-e-awam university of engineering, science and technology nawabshah, pakistan 2 department of automation, beijing university of chemical technology, beijing china corresponding author: engr.mohsinkoondhar@quest.edu.pk generally, dc motor is used in several applications like robotics and domestic appliances due to affordable cost and low complexity of control configuration for speed and torque control [3]. dc motors are considered as the best type of motors, in view of the speed control and speed regulation. numerous approaches are available to control the motor rotational speed and armature voltage control is one method among these methods [4, 6]. the dc machine by a dc power source for determining the inductance in a dc machine disables some difficulties related to traditional methods using ac source [7, 8]. mohsin ali (et al.), experimental based comparative analysis and characteristics of dc series motor by using different techniques (pp. 1 15) sjet | issn: 2616-7069 | vol. 3 | no. 1 | © 2020 sukkur iba university 2 dc machines are versatile energy conversion devices. these can be used for loads of high starting torques and to meet loads of high accelerating and decelerating torques [9]. for dc motors, the armature and field current are the same because the connection between them is standard [10, 11]. armature voltage/armature control methods can be used to control the speed of dc motor [12, 13]. 2. conventional controllers speed control of a motor escape intended to replace speed render to the demand of the workload connected with the motor. this preserve if done by mechanical expedients, such as by using stepped simple machines. nevertheless, speed control by the electrical way has greater advantages over mechanical. in many applications, dc motor is preferred over other types of motors because dc motors offer easy speed control. dc motor speed control methods depend upon, a. armature control method and b. armature voltage control method [14]. 2.1 armature control method it can apply during speeds where loading speed is not required. supply voltage usually invariable, by place a flexible rheostat in series with armature circuit, the voltage across armature may change shown in figure1. to decrease the armature speed potential difference beyond armature is dropped by increasing the value of resistance in the controller. for load-torque, speed is closely comparative to potential difference over the armature [15]. armature resistance control is simple for small motors while it wastes energy and unusable with large motors [16]. f ie ld ia controller resistance v fig 1: armature control method 2.2 armature voltage control method the speed of armature-controlled dc motor is controlled by armature voltage va and utilizes a constant field current shown in figure 2. load i la ra va ia vb ω τ fig 2: armature voltage control method the armature controlled can be expressed by equations as: iω = -b.ω + kt iatl (1) va vb = la dt dia + ra.ia (2) where b bv k   in the state-space form, the equation of dc motor is: mohsin ali (et al.), experimental based comparative analysis and characteristics of dc series motor by using different techniques (pp. 1 15) sjet | issn: 2616-7069 | vol. 3 | no. 1 | © 2020 sukkur iba university 3 0 1 1 0 t a l a ba a a a a b k d i i v ti r ki idt l l l                                       (3) 3. programmable logic controller dc motors are one of the devices that can be connected and controlled by plc [17]. the plc-based control system is a microprocessor-based controller. in this, a memory specifically programmable memory is used to store the instructions and various functions. presently programmable logic controller is vastly used in industry [6]. the plc is a functional computer employed in the machines where the control and operation of completion manner [18, 19]. it is the function of the programmable retention, accumulation guidance, and finishing including on and off shown in figure 4. figure 3 shows the basic arrangement of plc incorporated within the trainer. there are 20 i/o connectors, from which 10 for input and 10 for output, and a voltage stabilizer is used to maintain the required voltage. plcled lights input and output connectors on off pushbuttons stabilizer power supply extension fig 3: plc 4. plc ladder diagram for ease of programming, the programmable controller is advanced by adopting existing relay ladder design and expressions to take as program logics, necessary to control the machine or process. a relay ladder diagram is shown in figure 6. other part of factory industrial network (middle level) central plc controller input sensing devices output load devices local plc controller visual and sound signals local process control system fig 4: plc layout plc input control program outputs fig 5: plc as a control action (y1) (t1 k200) (y2) (t2 k200) x1 t1 y1 t2 t1 t2 y2 fig 6: ladder diagram of a plc mohsin ali (et al.), experimental based comparative analysis and characteristics of dc series motor by using different techniques (pp. 1 15) sjet | issn: 2616-7069 | vol. 3 | no. 1 | © 2020 sukkur iba university 4 4.1 dc motor characteristics with armature controller the characteristic of the motor means the determination relationship between speed, power, and current without load. figure 7 shows the experimental setup of the dc series motor with the armature controller. 4.1.1 torque vs. speed characteristics of dc motor with armature controller the characteristic result of torque vs. speed of dc series motor is presented in table 1 and graphically present shown in figure 8. in this table there are different levels of supply voltages are supplied and different torque are applied as a load from 0 nm to 1 nm in equal of 1 step respectively in order to observe the effectiveness of torque on the speed of dc motor. it is clearly mentioned in the table that if the value of torque increased from 0.1 nm to 1 nm than the speed of dc motor decreased figure 8 illustrates that as supply voltages raises from 30 to 50 voltages the speed of dc series motor is increased but as torque increases simultaneously the speed of dc series motor decreases. fig 7: experimental setup of dc series motor with armature controller table 1: toque speed characteristics with armature controller torque (n-m) v=30 v v=35 v v=40 v v=45 v v=50 v armature controller speed (rpm) speed (rpm) speed (rpm) speed (rpm) speed (rpm) 0 1125 1440 1750 1980 2280 0.1 1065 1380 1690 1930 2265 0.2 1034 1336 1620 1890 2110 0.3 1000 1278 1555 1850 2080 0.4 968 1240 1510 1740 1960 0.5 924 1210 1470 1680 1910 0.6 886 1170 1400 1580 1703 0.7 868 1135 1340 1500 1680 0.8 852 1090 1290 1430 1660 0.9 809 1030 1280 1370 1600 1 770 1008 1222 1340 1530 mohsin ali (et al.), experimental based comparative analysis and characteristics of dc series motor by using different techniques (pp. 1 15) sjet | issn: 2616-7069 | vol. 3 | no. 1 | © 2020 sukkur iba university 5 fig 8: torque vs. speed characteristics of dc series motor 4.1.2 torque vs. current characteristics of dc series motor with armature controller result of torque and current characteristic of dc series motor presented in table 2 and graphically present in figure 9. in this table there are different levels of supply voltages are supplied and different torque are applied as a load from 0 nm to 1 nm in equal of 1 step respectively in order to observe the effectiveness torque on the speed of dc motor. clearly mention in the table that if the value of torque varies from 0.1 n-m to 1 n-m than the speed of dc motor decreased. table 2: torque current characteristics dc series motor torque (n-m) v=30v v=35v v=40v v=45 v v=50v armature controller current (a) current (a) current (a) current (a) current (a) 0 0.8 0.7 0.7 0.7 0.7 0.1 0.8 0.8 0.8 0.8 0.8 0.2 0.8 0.8 0.8 0.8 0.8 0.3 0.8 0.9 0.9 0.9 0.8 0.4 0.9 0.9 0.9 0.9 0.9 0.5 0.9 0.9 0.9 0.9 0.9 0.6 0.9 0.9 0.9 0.9 0.9 0.7 1 1 1 1 1 0.8 1 1 1 1 1 0.9 1 1 1 1 1 1 1 1 1 1 1 torque-speed characteristics of dc series motor 0 500 1000 1500 2000 2500 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 torque (nm} s p e e d o f m o to r (r p m ) v = 30 volts v = 35 volts v = 40 volts v = 45 volts v = 50 volts mohsin ali (et al.), experimental based comparative analysis and characteristics of dc series motor by using different techniques (pp. 1 15) sjet | issn: 2616-7069 | vol. 3 | no. 1 | © 2020 sukkur iba university 6 fig 9: torque vs. current characteristics of dc series motor 4.1.3 torque vs. power characteristics of dc series motor with armature controller the characteristic result of the torque and power of dc series motor is presented in table 3 and graphically present shown in figure 10. in this table there are different levels of supply voltages are supplied and different torque are applied as a load from 0 nm to 1 nm in equal of 1 step respectively to observe the effectiveness of torque on the speed of dc motor. here clearly mention in the table that if the value of torque increased from 0.1 nm to 1 nm than the speed of dc motor decreased. table 3 torque power characteristics dc series motor torque (n-m) v=30 v v=35 v v=40 v v=45 v v=50 v armature controller power (watt) power (watt) power (watt) power (watt) power (watt) 0 24 24.5 28 31.5 35 0.1 24 28 32 36 40 0.2 24 28 32 36 40 0.3 24 31.5 36 40.5 40 0.4 27 31.5 36 40.5 45 0.5 27 31.5 36 40.5 45 0.6 27 31.5 36 40.5 45 0.7 30 35 40 45 50 0.8 30 35 40 45 50 0.9 30 35 40 45 50 1 30 35 40 45 50 torque-current characteristics of dc series motor 0.6 0.65 0.7 0.75 0.8 0.85 0.9 0.95 1 1.05 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 torque (nm} c ur re nt o f m ot or (a m pe re s) v = 30 volts v = 3050 volts v = 3550 volts v = 3550 volts v = 30 volts mohsin ali (et al.), experimental based comparative analysis and characteristics of dc series motor by using different techniques (pp. 1 15) sjet | issn: 2616-7069 | vol. 3 | no. 1 | © 2020 sukkur iba university 7 fig 10: torque power characteristics of dc series motor 4.2 experimental structure of dc series motor with plc `experimental setup is illustrated in figure 11. hgdc feba 0 1 0 250 200 150 100 50 10 50 40 30 20 0.6 0.4 0.2 10 8 0.8 1.0 2 4 6 0 dc voltmeter dc ammeter 230 v output l1 nl3l2 + l1 l2 l3 n + 0-100 1 a 10 a l1 l2 l3 ~ ~ y 0 y 1 y 2 y 3 y 4 y 5 y 6 y 7 y 8 y 9 + s x 13 x1 2 x 11 x1 0 x 9 x 8 x 7 x 6 x 5 x 4 x 3 x 2 x 1 x 0 + input output fuse range 500 v 250 v 50 v com 10 a 5 a 1 a com variable o/p voltage fixed dc o/p 220 5 a max. 3-ɸ circuit breaker with no voltage release pc fig 11: experimental structure of dc series motor with plc 4.2.1 dc motor torque vs. speed characteristics with plc the characteristic result of torque vs. speed of dc series motor is presented in table 4 and graphically present shown in figure 12. in this table there are different levels of supply voltages are supplied and different torque are applied as a load from 0 nm to 1 nm in equal of 1 step respectively to observe the effectiveness of torque on the speed of dc motor. it’s clearly mentioned in the table that if the value of torque increased from 0.1 nm to 1 nm than the speed of dc motor decreased. torque-power characteristics of dc series motor 10 15 20 25 30 35 40 45 50 55 60 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 torque (nm} p o w er o f m o to r (w at ts ) v = 50 volts v = 30 volts v = 35 volts v = 40 volts v = 45 volts mohsin ali (et al.), experimental based comparative analysis and characteristics of dc series motor by using different techniques (pp. 1 15) sjet | issn: 2616-7069 | vol. 3 | no. 1 | © 2020 sukkur iba university 8 table 4: dc series motor torque vs. speed characteristics with plc torque (n-m) v=30 v v=35 v v=40 v v=45 v v=50 v with plc speed (rpm) speed (rpm) speed (rpm) speed (rpm) speed (rpm) 0 1000 1200 1530 1736 1940 0.1 982 1150 1520 1690 1700 0.2 950 1130 1480 1650 1680 0.3 880 1070 1320 1470 1590 0.4 870 1060 1300 1460 1580 0.5 850 978 1150 1290 1400 0.6 800 950 1140 1230 1380 0.7 670 900 1040 1200 1250 0.8 650 833 1000 1100 1230 0.9 630 820 935 1060 1220 1 594 800 900 980 1150 fig 12: dc series motor torque vs. speed characteristics with plc [5] torque vs. current characteristics of dc series motor with plc the characteristic result of torque and current of dc series motor is presented in table 5 and graphically present shown in figure 13. in this table there are different levels of supply voltages are supplied and different torque are applied as a load from 0 nm to 1 nm in equal of 1 step respectively to observe the effectiveness of torque on the speed of dc motor. it is clearly mentioned in the table that if the value of torque varies from 0.1 nm to 1 nm than the speed of dc motor decreased. torque-speed characteristics of dc series motor with plc 0 500 1000 1500 2000 2500 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 torque (nm} s p ee d o f m o to r (r p m ) v = 30 volts v = 35 volts v = 40 volts v = 45 volts v = 50 volts mohsin ali (et al.), experimental based comparative analysis and characteristics of dc series motor by using different techniques (pp. 1 15) sjet | issn: 2616-7069 | vol. 3 | no. 1 | © 2020 sukkur iba university 9 table 5: dc series motor torque current characteristics with plc fig 13: dc series motor torque vs. current characteristics of with plc 4.2.2 dc series motor torque power characteristics with plc characteristic result of torque power of dc series motor presented in table 6 and graphically present in figure 14. in this table respectively to observe the effectiveness of torque on the speed of dc motor. it is clearly mentioned in the table that if the value of torque increased from 0.1 nm to 1 nm than the speed of dc motor decreased torque (n -m) v =30 v v =35 v v =40 v v =45 v v =50 v with plc current (a) current (a) current (a) current (a) current (a) 0 0.8 0.8 0.8 0.9 0.9 0.1 0.9 0.9 0.9 0.9 0.9 0.2 0.9 0.9 0.9 0.9 0.9 0.3 0.9 0.9 0.9 0.9 0.9 0.4 0.9 0.9 0.9 0.9 0.9 0.5 1 1 1.1 1.1 1.1 0.6 1.2 1 1.1 1.1 1.1 0.7 1.2 1.2 1.2 1.2 1.2 0.8 1.2 1.2 1.2 1.2 1.3 0.9 1.2 1.2 1.2 1.2 1.3 1 1.3 1.3 1.3 1.3 1.3 torque-current characteristics of dc series motor with plc 0.6 0.7 0.8 0.9 1 1.1 1.2 1.3 1.4 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 torque (nm} c u rr e n t o f m o to r (a m p e re s ) v = 3040 volts v = 3050 volts v = 4550 volts v = 3050 volts v = 30 volts v = 3035 volts v = 4050 volts v = 35 volts v = 4050 volts v = 3045 volts v = 50 volts mohsin ali (et al.), experimental based comparative analysis and characteristics of dc series motor by using different techniques (pp. 1 15) sjet | issn: 2616-7069 | vol. 3 | no. 1 | © 2020 sukkur iba university 10 table 6 torque power characteristics dc series motor with plc fig14: dc series motor torque vs. power characteristics with plc torque (n-m) v=30v v=35v v=40 v v=45 v v=50 v with plc power (watt) power (watt) power (watt) power (watt) power (watt) 0 24 28 32 40.5 45 0.1 27 31.5 36 40.5 45 0.2 27 31.5 36 40.5 45 0.3 27 31.5 36 40.5 45 0.4 27 31.5 36 40.5 45 0.5 30 35 44 49.5 55 0.6 36 35 44 49.5 55 0.7 36 42 48 54 60 0.8 36 42 48 54 65 0.9 36 42 48 54 65 1 39 45.5 52 58.5 65 torque-power characteristics of dc series motor with plc 10 20 30 40 50 60 70 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 torque (nm} p ow er o f m ot or (w at ts ) v = 50 volts v = 30 volts v = 35 volts v = 40 volts v = 45 volts mohsin ali (et al.), experimental based comparative analysis and characteristics of dc series motor by using different techniques (pp. 1 15) sjet | issn: 2616-7069 | vol. 3 | no. 1 | © 2020 sukkur iba university 11 table 7 comparison of torque speed characteristics dc series motor plc with armature controller 4.3 characteristics comparison of dc series motor with plc and armature controller a comparison between plc and armature controller here is presented. 4.3.1 comparison torque vs. speed characteristics of dc series motor with plc and armature controller a comparison between torque and speed are shown in table 7 and graphically represented in figure 15. torqu e (n .m) speed (rpm) v = 30v v = 35v v = 40v v = 45v v = 50v witho ut plc wit h pl c witho ut plc wit h pl c witho ut plc wit h pl c witho ut plc wit h pl c witho ut plc wit h pl c 0 1125 100 0 1440 120 0 1750 153 0 1980 173 6 2280 194 0 0.1 1065 982 1380 115 0 1690 152 0 1930 169 0 2265 170 0 0.2 1034 950 1336 113 0 1620 148 0 1890 165 0 2110 168 0 0.3 1000 880 1278 107 0 1555 132 0 1850 147 0 2080 159 0 0.4 968 870 1240 106 0 1510 130 0 1740 146 0 1960 158 0 0.5 924 850 1210 978 1470 115 0 1680 129 0 1910 140 0 0.6 886 800 1170 950 1400 114 0 1580 123 0 1703 138 0 0.7 868 670 1135 900 1340 104 0 1500 120 0 1680 125 0 0.8 852 650 1090 833 1290 100 0 1430 110 0 1660 123 0 0.9 809 630 1030 820 1280 935 1370 106 0 1600 122 0 1 770 594 1008 800 1222 900 1340 980 1530 115 0 mohsin ali (et al.), experimental based comparative analysis and characteristics of dc series motor by using different techniques (pp. 1 15) sjet | issn: 2616-7069 | vol. 3 | no. 1 | © 2020 sukkur iba university 12 fig 15: graphically representation of torque and speed of dc series motor with plc and armature controller [5]. 4.3.2 characteristics comparison of torque vs. current of dc series motor with plc and armature controller comparison between torque and current are shown in table 8 and graphically represented in figure 16. table 8 comparison of torque current characteristics dc series motor plc with armature controller torqu e (nm) current (ampere) v =30v v =35v v =40v v =45v v =50v witho ut plc with plc witho ut plc with plc witho ut plc with plc witho ut plc with plc witho ut plc with plc 0 0.8 0.8 0.7 0.8 0.7 0.8 0.7 0.9 0.7 0.9 0.1 0.8 0.9 0.8 0.9 0.8 0.9 0.8 0.9 0.8 0.9 0.2 0.8 0.9 0.8 0.9 0.8 0.9 0.8 0.9 0.8 0.9 0.3 0.8 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.8 0.9 0.4 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.9 0.5 0.9 1 0.9 1 0.9 1.1 0.9 1.1 0.9 1.1 0.6 0.9 1.2 0.9 1 0.9 1.1 0.9 1.1 0.9 1.1 0.7 1 1.2 1 1.2 1 1.2 1 1.2 1 1.2 0.8 1 1.2 1 1.2 1 1.2 1 1.2 1 1.3 0.9 1 1.2 1 1.2 1 1.2 1 1.2 1 1.3 1 1 1.3 1 1.3 1 1.3 1 1.3 1 1.3 mohsin ali (et al.), experimental based comparative analysis and characteristics of dc series motor by using different techniques (pp. 1 15) sjet | issn: 2616-7069 | vol. 3 | no. 1 | © 2020 sukkur iba university 13 fig 16: graphically representation of torque and current of dc series motor with plc and armature controller 4.3.3 comparison torque power characteristics of dc series motor with plc and armature controller comparison between torque and current are shown in table 9 and graphically represented in figure 17. table 9 comparison of torque power characteristics dc series motor plc with armature controller torque (nm) power v =30v v =35v v =40v v =45v v =50v witho ut plc with plc witho ut plc with plc witho ut plc with plc witho ut plc with plc witho ut plc with plc 0 24 24 24.5 28 28 32 31.5 40.5 35 45 0.1 24 27 28 31.5 32 36 36 40.5 40 45 0.2 24 27 28 31.5 32 36 36 40.5 40 45 0.3 24 27 31.5 31.5 36 36 40.5 40.5 40 45 0.4 27 27 31.5 31.5 36 36 40.5 40.5 45 45 0.5 27 30 31.5 35 36 44 40.5 49.5 45 55 0.6 27 36 31.5 35 36 44 40.5 49.5 45 55 0.7 30 36 35 42 40 48 45 54 50 60 0.8 30 36 35 42 40 48 45 54 50 65 0.9 30 36 35 42 40 48 45 54 50 65 1 30 39 35 45.5 40 52 45 58.5 50 65 0.5 0.8 1.1 1.4 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 torque (nm) c u rr e n t (a m p e re s ) v = 3550volts v = 3045volts v = 30volts v = 50volts v = 50volts without plc with plc mohsin ali (et al.), experimental based comparative analysis and characteristics of dc series motor by using different techniques (pp. 1 15) sjet | issn: 2616-7069 | vol. 3 | no. 1 | © 2020 sukkur iba university 14 fig 17: graphically representation of torque and power of dc series motor with plc and armature controller. figure 17 represents the relationship between power with respect to torque with and without plc. at different voltages from 30 to 50 v as torque gradually increases from 0 nm to 1 nm power is increased. 5 conclusion and future work in this paper, the characteristics results of dc series motor have been obtained by using different controller techniques such as plc and armature controllers. in the above results and discussion, it can be easily understood that the best results are obtained by using plc as compare to the armature controller. by this research work, speed and torque of dc motor can be controlled for laboratories and industrial applications. this work can be further enhanced in the future in the following ways.  it can be applied in industry.  it is also used in an educational institute.  an adaptive controller can be used for motor control.  combined controlling techniques with plc can be used to observe torque vs. speed characteristics.  matlab based motor can be simulated for power drives and medical appliances. references [1] p. malviya and m. dubey, 2015, “speed control of dc motor a review”, international journal of engineering sciences and research technology, 4(8), pages 298-305. [2] n. tripathi, r. singh and r. yadav, 2015, “analysis of speed control of dc motor –a review study”, international research journal of engineering and technology, 2(8). [3] s. b. kumar, m. h. ali and a. sinha, 2014, “design and simulation of speed control of dc motor by artificial neural network technique”, international journal of scientific and research publications, 4(7). [4] m. a. koondhar, a. k. junejo, a. s. saand, and m. u. keerio, 2016, “speed control of dc series motor with conventional and plc techniques”, international journal of information technology and electrical engineering, 4(5) , pages 21-26. [5] koondhar, m.a, “speed and torque control of dc series motor by using plc”, master thesis, 2016. mohsin ali (et al.), experimental based comparative analysis and characteristics of dc series motor by using different techniques (pp. 1 15) sjet | issn: 2616-7069 | vol. 3 | no. 1 | © 2020 sukkur iba university 15 [6] v. naveen and t. b. isha, 2017 “ a low cost speed estimation technique for closed loop control of bldc motor drive”, ieee international conference on circuit, power and computing technologies (iccpct), april 2017, pages 1-5. [7] s. s. keream, k.g. mohammed and m.s. ibrahim, 2018, “analysis study in principles of operation of dc machine”, journal of advance research in dynamical and control systems, 10(2), pages 2323-2329. [8] n. chuang, t. j. gale, and r. a. langman, 2016, “developing measuring inductance strategies on a direct current machine using a dc source with magnetic saturation”, international journal of circuit theory and applications, 44, pages 1094-1111. [9] d. rajesh and d. ravikumar, s.k.bharadwaj and b. k. s. vastav, 2016, “design and control of digital dc drives in steel rolling mills”, ieee international conference on inventive computing technologies, 3, pages 1-5. [10] h. t. h. thabet and m. a. qasim, 2016, “measurement of a dc series motor torque based on plc techniques” kufa journal of engineering, 7(1), pages 93-103. [11] n. k. nambisan and b. n. sarkar, 2014, “study of speed control of dc series motor using dc chopper”, international journal of advanced research in electrical, electronics and instrumentation engineering, 3(8), pages 11116-11123. [12] a. mohammad and s. b. billah, 2015, “analysis of speed control of series dc motor using diverter and observation of speed saturation point”, international conference on electrical engineering and information communication technology, may 2015, pages 1-4. [13] mehta, v. k., and mehta, r. (2008). principle of electrical machines. s. chand. [14] r. rudra and r. banerjee, 2017, “ modeling and simulation of dc motor speed regulation by field current control using matlab”, international journal of computer electrical engineering, 2(9), pages 502-512. [15] b. l. theraja and a. k. theraja, 2017, textbook of electrical technology volume i, in si system of units. s. chand, 2017. [16] h. f. frayyeh, m. a. mukhlif, a.m. abbood and s. s. keream, 2019, “speed control of direct current motor using mechanical characteristics”, journal of southwest jiaotong university, 54(4). [17] m.s. saleh, k. g. mohammed, z.s. al-sagar and a. z. sameen, 2018, “design and implementation of plc-based monitoring and sequence controller system”, journal of advance research in dynamical and control systems, 10(2), pages 2281-2289. [18] j. r. monfared, m. fazeli and y. lotfi, 2015, “design and plc implementation for speed control of dc motor using fuzzy logic”, journal of electrical andcomputer engineering innovations, 3(2), pages 71-75. [19] l. guo p. pecen, 2008, “design projects in a programmable logic controller (plc) course in electrical engineering technology”, in american society for engineering education, 1(10), pages 1-10. [20] k. venkateswarlu and c. chengaiah, 2014, “comparative study on dc motor speed control using various controllers”, global journal of research in engineering. [21] s. sharma, s. s. oberoi and s. nair, 2014, “speed control method of dc series motor”, international journal of innovative research in technology, 1(6), pages 14501453. an energy efficient crypto suit for secure underwater sensor communication using genetic algorithm vol. 5, no. 1 | january – june 2022 sjet | p-issn: 2616-7069 |e-issn: 2617-3115 | vol. 5 no. 1 january – june 2022 19 design and development of gui for the mitigation of chromatic dispersion: a new approach bhagwan das1, nawaz ali zardari2, farah deeba3, dileep kumar ramnani4 abstract: chromatic dispersion (cd) is the important effect that is considering for optical communication system design as it broadens the pulse during the propagation along channel resulting in pulse overlapping and ultimately bit errors raises. the increment in bit error, in result reduce the performance of optical system. therefore, mitigation cd is necessary in order to improve the performance of optical communication system. there are several techniques of mitigating cd have been proposed and all based on coding based and this will create issues for the communication design engineer that every time the parameters need to be revised. in order to avoid this issue, the ease for the system design engineer has been created in designing the graphical user interface (gui). in this work, gui is designed and developed that will request the parameters need to be select for the optical system and it will describe the all process for mitigating it from the system. in the first, the communication system designer have to select the transmission along with modulation and after that transmission at distance is asked in terms of km. the cd is mitigated uses least mean square technique and fast fourier transform method. the further smoothing of signal is improved by pulse shaping via using the raised cosine filter. in the end, the original signal and the compensated signal are defined. the ber is also calculated to show whether the reduction through dsp is performed. the gui is developed in matlab and every button backhand the strong coding is used in c++ for developing the system. the proposed design of gui for the reduction in chromatic dispersion has successfully attained the reduction of cd as 40%. in addition to that ber of 10-3 has been attained using the proposed system. the system was designed and developed for the qam modulation schemes. the designed system has been tested for the 10 gb/s data rate. the designed and developed system offers the ease of use for the communication engineer, in which on one platform the user can observer well the optical system instead of programming. keywords: chromatic dispersion, digital signal processing, graphical user interface, ms visio. 1department of electronic engineering, quaid-e-awam university of engineering, science and technology, nawabshah, sindh, pakistan. 2department of telecommunication engineering, quaid-e-awam university of engineering, science and technology, nawabshah, sindh, pakistan. 3faculty of engineering and science technology, department of computing, hamdard university karachi pakistan 4department of electronic engineering, dawood university of engineering & technology, karachi. corresponding author: engr.bhagwandas@hotmail.com mailto:engr.bhagwandas@hotmail.com design and development of gui for the mitigation of chromatic dispersion: a new approach (pp. 19 31) sukkur iba journal of emerging technologies sjet | vol. 5 no. 1 january – june 2022 20 optical communication is now widely used for high speed communication systems [1]. during the transmission, several transmission impairments effect the performance of systems such as linear and nonlinear parameters. chromatic dispersion is one of them. many techniques have already been utilized for the cd reduction [2]. when the signal propagates along fiber optic due to refractive index the pulse broadening effects occur and after some distance signal is lost. the main aim is that to design a platform for cd reduction which should be user friendly even we can execute it without programming [3]. many researchers has developed the system related chromatic dispersion as discussed in. however, each system has its own advantages and disadvantages [4]. in this research, the cd is reduced in the electrical domain via graphical user interface that will help in designing the future communication system in order to solve chromatic issues. in the next section, the problem related to optical system designing for mitigation of chromatic dispersion is discussed and also the proposed work details are descripted in comparison to the work that have been carried out in the past. the different researchers have worked on reduction of chromatic dispersion. each work has its own significant in terms of application and results attained. in this paper, the research paper that are only related to development of gui or similar software tool are discussed in order to demonstrate the need of efficient gui design and development for the chromatic dispersion for the various application of optical communication. in this work, author amiri in [5] focused the chromatic dispersion compensation is performed numerically for 250 km fiber and ber achieved was 10-2 for optical wireless channel. however, the system designed only based on numerical design and simulation was carried out using the ordinary programming no convenient way of demonstrating the simulation was proposed. the author neumann in [6] demonstrated the chromatic dispersion using discrete-time filtering strategy the system was designed using the programming no simulator to gui was designed for the convenient of optical designer was considered. the system was tested on qpsk modulation with some reduction of complexity in existing circuits. the author wu in [7] has focused the equalization of chromatic dispersion equalization for optical communication using pso algorithm the proposed system was designed using the programming no simulator or gui was created in order to facilitate the design for future perspective. the system was tested for qam modulation and reduction of chromatic dispersion with 25% was attained using the proposed system. the filter also discussed the complex design issues. the author udayakumar in [8] designed the chromatic dispersion compensation system using fbg fiber bragg grating. the worked was carried out using the optisystem software. the link is limited to few gb/s and ber was not so much fascinating as per requirements of optical wireless channel. it is important to note that optisystem is an expansive simulation tool for developing optical related system and it increase the cost of design system using analysis. the author mustafa in [9] worked on compensation of chromatic dispersion in order to maximize transmission bit rate. the work is carried out using soliton transmission technique. it is important to discuss that work was carried using expansive software. beside that the optical soliton wave technique is utilized and system was designed for the 1.9932. the author galvis-velandia in [10] presented the analysis of dispersion compensation using self-phase modulation using modulator scheme for 50 km fiber link. the system was designed and analyzed for spectral separation of the transmitted channels for 0.2 nm the system has some harmonics alter the spectral density waveform. the system was designed using the programming no simulator or gui was design and development of gui for the mitigation of chromatic dispersion: a new approach (pp. 19 31) sukkur iba journal of emerging technologies sjet | vol. 5 no. 1 january – june 2022 21 designed to help the researcher and optical designer to modify the system characteristics for future design aspects. chromatic dispersion (cd) is key parameter that is considered well when designing the optical communication [11]. the more cd in the signal will increase the inter symbol interference (isi) that will cause increase in error in transmissions [12]. in result, more bit are corrupted and system performance is highly degraded. because of that mitigation of cd is important in designing the high performance optical communication [13]. in the past, various cd mitigation have been proposed via signal processing and through programing [14]. there are several issues are encountered when mitigating the cd via programming and signal processing [15]. one is every time, when system designer changes the other parameters the programmer needs to write the all code again and have to check the response of each parameter again and again this will consume lots of time in just checking the system [16]. furthermore, the signal processing are limited in terms of smoothing the corrupted signal. in comparison to past, the proposed work designed and developed a convenient gui for the communication system designer that will just ask the programmer to insert values and at back hand the programming for gui is executing all the variation that is carried out for changing the system. one more advantages of the proposed system is that it will show instant outcome of the developed changes for cd means every time like in the past, the system designed don’t need to write and execute the code. the proposed system need all the values of parameters selection. in the next section, the system designing is discussed in detail. the design and development of gui for cd mitigation is carried out in different step as shown in fig. 1. the design steps are shown in flow chart. start end generate input signal observe chromatic dispersion convert signal in to dig ital domain convert signal into optical d omain devel op optical channel apply digital si gnal processing create gui for visualization of signals and chromatic dispersion yes no th en change parameters fig. 1. flow chart of designed and developed system in fig. 1, the proposed work research flow chart is depicted. it states that in the first design step need to generate an analog signal and its output can be seen in gui after that this analog signal is converted in digital signal via analog-to-digital conversion. here, the outcome of digital signal can be viewed at gui as well as shown in flow chart fig. 1. after that using modulation, the signal is converted in optical signal as discussed in [17]. the details of the techniques are shown in methodology section. this optical signal can be seen in gui. after that this signal propagated at optical channel and where the effect of chromatic dispersion is observed this can be seen on gui. if the chromatic dispersion is observed the digital signal processing techniques are applied in order to mitigate the cd. if there is no cd is observed than the parameters of optical fiber channel are varied [18]. here, design and development of gui for the mitigation of chromatic dispersion: a new approach (pp. 19 31) sukkur iba journal of emerging technologies sjet | vol. 5 no. 1 january – june 2022 22 both signal can be observed on gui. before chromatic dispersion and after chromatic dispersion as shown in fig. 1. in the next section, the detailed methodology of the work is discussed including the analytical work done in order to design and develop the system that mitigates the cd and also the design of gui and its outcome is discussed in detail. in this work, the development of chromatic dispersion mitigation is performed analytically and after that system is programmed in matlab and in the last design of gui is executed as shown in fig. 2. input analog signal generation analog to dig ital convers ion convers ion in optical d omain optical f iber channel demo dulati on of converti ng in electrical signal apply digital processing for removing dispersion gui d esign. fig. 2. methodology for development of chromatic dispersion and design of gui the methodology of developing the chromatic dispersion reduction is shown in fig. 2. in the first, the chromatic dispersion reduction is discussed and after that design of gui is discussed. a. development of mitigation of chromatic dispersion the input signal is generated using matlab, the analog signal is generated of 50 mhz with normalized amplitude values. the signal conditioning of input signal (digitlization) via analog to digital conversion is carried. the generated analog test signal is converted into digital with the frame size of length 128 bits. the digital signal has 128 number of bits and cyclic prefix that reduce the isi during the transmission and conversion from digital processing techniques [19] for converting in digital domain, the 1 to 256 subcarrier having index from [-128 to 128] and [0 to 256] is considered. the following commanded are programed: channel_spacing = [0 256]; f= 50mhz; samples space= 10; [y, t] = a2d (channel, f, samples space) the above code converting the signal in digital domain and after that second stage is modulating the signal in optical domain. this action is performed using the modulation. the modulations are well known process to changing the characteristic of the signal [20]. there are many modulation schemes are there. they characterized based on amplitude, phase, and frequency. in this work, the 256 length of signal taken above is converted in optical signal via qam modulation the amplitude of carrier is modulated by 90º. the response of qam signal is shown in fig. 3. fig. 3. the constellation diagram the constellation diagram states that complex digital signal are converted in set in the optical symbols, bits are arranged in unique manner of direct modulation. the qam modulator is developed in matlab simulink. the model is sown in fig. 4. design and development of gui for the mitigation of chromatic dispersion: a new approach (pp. 19 31) sukkur iba journal of emerging technologies sjet | vol. 5 no. 1 january – june 2022 23 fig. 4. design of qam modulator from the design of qam modulator as shown in fig. 4. the signal is modulated in stream of bits formed by log2p, where p defines the no. of symbols. 16-qam modulations is performed in following way [21]: p = 256; i = log2(p); nsamp = 10; the signal that is modulated in converted above code converting the signal in digital domain and after that signal is converted in optical via direct modulation. this optical signal is ready to launch over optical fiber to be transmitted at different distances [22]. the signal propagation on optical fiber channel is performed using non-leaner schrödinger equation (nlse). this nlse is used to detonate all the basic parameters related to optical fiber transmission. this include losses in optical fiber, phase and group velocity, single phase modulation, nonlinear and linear effects in single mode fiber as shown (1) [21]: 𝜕𝐴 𝜕𝑧 + 𝑖 2 𝛽2 𝜕2𝐴 𝜕𝑡2 = 𝑖𝛾|𝐴|2𝐴−̶̶̶̶ 𝛼 2 𝐴 (1) equation 1 defines the propagation of signal that is carried out from qam modulation over optical fiber. the channel is characterized based on single mode fiber (smf). the parameters that are characterized for designing the optical propagation are defined as a defies the power of optical field, α defines the disturbance in the signal, and the β is the one of the crucial parameters over which all the work is performed is chromatic dispersion. however, in this work, the second derivation of chromatic dispersion is taken in order to analyze the chromatic dispersion well in terms of spectrum. γ defines the nonlinear effect that defines the phase variation, z defines the dimension propagation and also the t defines the interval at which optical signal will prorogate inside the optical fiber [3]. the nlse is transform in matlab via split step fourier method (ssfm) this model is used as propagation model for transferring the signal over optical fiber [iv]. the simulation is carried for 20 km distance via ssfm. the model developed in matlab is used to program input signal, fiber loss db/km, and width of pulse in order to measure the chromatic dispersion. this include different measurement of optical amplitude, and step size for fourier transform, chirp factor for dispersion [11]. after launching the signal over optical fiber modulation is carried out in converting signal from optical to electrical signal for that demodulation is used as shown in fig. 5. fig. 5. demodulation of the signal the reason why the demodulation is performed is because before propagation signal was changes in nature. the demodulation is carried out in terns phase and amplitude of detected signal the signal is converted based on matlab model as shown in fig. 5. after that this transmitted signal over fiber optic is converted signal in electrical and onwards the electrical signal is used for chromatic dispersion mitigation using digital signal processing (dsp) techniques. chromatic dispersion widen the pulse width during the transmission at optical fiber. this produces losses in the signal and performance is further degraded. in this work, design and development of gui for the mitigation of chromatic dispersion: a new approach (pp. 19 31) sukkur iba journal of emerging technologies sjet | vol. 5 no. 1 january – june 2022 24 the chromatic dispersion is mitigated in the electric way, which is far better compare to existing techniques [12] for low dispersion system. the chromatic dispersion is taken in account from (1) and it is defined that chromatic dispersion is calculated as in (2) by abandoning the nonlinear effects from the transmission because no pump signal is used and there was no spikes in the signal recorded [13]: 𝜕𝐴 𝜕𝑧 = − 𝑖 2 𝛽2 𝜕2𝐴 𝜕𝑡2 (2) it was discussed earlier that second order of dispersion is taken for this work. the advantages are coming here because of time delay and different spectrum. the chromatic dispersion is calculated as in (3) [13]: 𝐷 = − 2𝛱𝑐 𝜆2 𝛽2 (3) where in (4) 𝜆 = − 2𝛱𝑐 𝜔 (4) this has the wavelength for dispersion at which pulse is broaden and wavelength interval. it is measured in terms of ps/nm/km. solving (2) in time domain yields the solution in (5) [15]: 𝜕𝐴(𝑧,𝑡) 𝜕𝑧 = 𝑗 𝐷𝜆2 4𝛱𝑐 𝜕2𝐴(𝑧,𝑡) 𝜕𝑡2 (5) the solution of (5) is not possible in time so the signal is converted in frequency domain for measuring the field pattern as in (6) [16]: 𝐴(𝑧,𝜔) = 𝐴(0,𝜔)𝑒 −𝑗 𝐷𝜆2 4𝛱𝑐 𝜔2𝑧 (6) by further solving for z = 0 at instantaneous value for frequency will generate the transfer function as in (7): 𝐻(𝑧,𝜔) = 𝑒 −𝑗 𝑑𝜆2 4𝛱𝑐 𝜔2𝑧 (7) after that signal having transfer function of chromatic dispersion in (7), the inverse fft is taken in order to show the signal in time domain via (8): ℎ(𝑧,𝑡) = √ 𝑐 𝑗𝐷𝜆2𝑧 𝑒 𝑗 𝛱𝑐 𝐷𝜆2𝑧 𝑡2 (8) further, signal is given to fir filter to mitigate the chromatic dispersion in time domain as in (9) [18]: 𝑧(𝑛) = 𝑎0𝑤(𝑛)+𝑎1𝑤(𝑛 −1) + −−−−−− → 𝑎𝑁𝑤(𝑛−𝑁) (9) where in (9) input signal with filter weights are shown for filter length to generate output as in z. i this work, least mean square (lms) is used to mitigate the chromatic dispersion to maintain the accuracy and relevancy. lms is used to maintain the filter weight. tap weights should be initialized except the central one that is set to unity corresponding to no filtering to mitigate chromatic dispersion [22].,the filter signal still have some noises. for that smoothing of signal is required. in this work, the raised cosine filter improves the shape of pulse. the filter is designed and constructed via (10) [12]: 𝐺(𝜔) = { 𝑇 𝑓𝑜𝑟 |𝜔| ≤ (1−𝛼) 𝜔𝑠 2 𝑇 2 {1−𝑠𝑖𝑛[ 𝑇 2𝛼 (|𝜔| − 𝜔𝑠 2 )]} 𝑓𝑜𝑟 (1+𝛼) 𝜔𝑠 2 ≤ |𝜔| ≤ (1+𝛼) 𝜔𝑠 2 0 𝑒𝑙𝑠𝑒𝑤ℎ𝑒𝑟𝑒 (10) the signal received from filter is observed in response and it was defined that phase has edges and tracking needs to be remove for that phase tracking is used to remove error at design and development of gui for the mitigation of chromatic dispersion: a new approach (pp. 19 31) sukkur iba journal of emerging technologies sjet | vol. 5 no. 1 january – june 2022 25 the edges by mitigating the chromatic dispersion. the signal is chucked in smaller window and errors at the edges at specific frequencies are removed via kaiser window as shown in (11) [13]: 𝑤[𝑛] = { 𝐼0 [𝛽√1−( 𝑛 −𝑀/2 𝑀/2 ) 2 ] 𝐼0(𝛽) 0 ≤ 𝑛 ≤ 𝑀 0 𝑒𝑙𝑠𝑒 (11) this is improving the detected stream from long stream of bits by changing the center lobe width and sided lobe. after that bit error rate is calculated to check that chromatic dispersion is mitigated? ber is number of errors occurring over a time at which signal is received. the error rate depends on signal to noise ratio determined by q factor. ber was calculated via (12) [13]: (12) as the q or quality factor is increased ber decreased and it is defined that by mitigating the chromatic dispersion, the qfactor is increased and ber furthermore, the performance is setup via eye diagram. it gives visual of signal in the shape of an eye to asses maximum transmission rate of a system, it is related to ber as the chromatic dispersion is more the eye will be close and if chromatic dispersion mitigation is archived the eye will be open [27-28]. in the next section, the design of gui of carried for finalizing the work step of mitigating the chromatic dispersions. graphical user interface (gui) is developed in order to mitigate the chromatic dispersion for its better visualization. it was discussed before that before designing of the system programming was required. gui helps in recalling the signals and after that their respective output responses are shown in the results section. the gui setup is shown in fig. 6, the process involves in reducing the chromatic dispersion are shown. the gui is characterized in a different section. fig. 6. gui setup for designing the mitigation of chromatic dispersion firstly, the system design via (1) (12) by using the programming is transformed in gui. the system designer can insert the value for generating the input signal of any frequency and after that from just signal click the signal will be converted in digital domain [29-30]. the next tag is used for converting optical signal from electrical one via modulation. after that fiber length is choose in order to select the length of fiber. the signal shows the propagation in gui. the gui measure the dispersion calculated from (6). after that dps technique of having raised cosine filter and kaiser window is used in order to mitigate the dispersion. this gui can show the repose of the signal before removing the dispersion and after applying the dsp techniques the response of chromatic dispersion can be shown in gui as shown in fig. 6. 2 21 2 q e ber q −     =         design and development of gui for the mitigation of chromatic dispersion: a new approach (pp. 19 31) sukkur iba journal of emerging technologies sjet | vol. 5 no. 1 january – june 2022 26 not only this, the gui also gives the information about ber that was calculated via (12) along with eye diagram. these all measurements defines that signal has the chromatic dispersion during the transmission and via developing the gui it easily describe the response of all optical communication under one system. the designer don’t have to go anywhere else program for displaying the response of developed optical system. furthermore, the parameters and system can be changed easily without any program efforts. in the next section, results for gui designed and response of designing the mitigation of chromatic dispersion is show step by step. in this work, the mitigation of chromatic dispersion is carried in matlab. the chromatic dispersion is removed by using the dsp technique in which raised cosine filter method and kaiser window method are used. the response are recorded based on bit error rate and eye diagram. the chromatic dispersion mitigation is carried out analytically and response are observed on gui. fig. 7. the spectrum of the input signal transmitted at a channel the gui generates the response of signal spectrum of input transmitted signal which is converted analog to digital is appeared in right most box where star is mentioned as shown fig. 7. the response of modulation for qam-16 is display via gui as shown in fig. 8. fig. 8. the response of gui for modulation (16 qam) it can be analyzed from fig. 8 that the modulation of 16 qam modulation scheme is used for the gui. the 16-qam scheme is widely used scheme for optical communication system due to less effect of noise during the transmission. it was discussed that split step fourier method is used to design the optical fiber model. the response of optical fiber model is shown in fig. 9 that is generated using the designed gui. fig. 9. response of gui for pulse model fiber optic the response of optical fiber model is developed from gui modeling and depicted in fig. 9. the optical model is designed using the nlse equation. the response is characterized using different parameters such as; amplitude of pulse, distance and time for pulse incurred in optical fiber. the output of chromatic dispersion is performed through raised cosine and kaiser window in time domain. the gui is modeled to generate the response of mitigation of chromatic dispersion as shown in fig. 10. design and development of gui for the mitigation of chromatic dispersion: a new approach (pp. 19 31) sukkur iba journal of emerging technologies sjet | vol. 5 no. 1 january – june 2022 27 fig. 10. response of gui for showing mitigation of chromatic dispersion in time domain it was discussed that mitigation of chromatic dispersion was carried out using raised cosine filter and kaiser window. the gui has been created for generating the response of raised cosine filter as shown in fig. 11. fig. 11. response of gui for raised cosine filter output after improving the shape of the pulse the phase is improved through the kaiser window as shown in gui in fig.12 at frequency of 1g hz: fig. 12. fig. 12. response of gui for time domain window filtration fig. 13. the response of gui for generating the ber for mitigation of chromatic dispersion after applying the chromatic dispersion mitigation. it is important to show the performance of the system. it was discussed that chromatic dispersion mitigation is carried out using bit error rate and eye diagram. the ber diagram is developed using gui as shown in fig. 13 design and development of gui for the mitigation of chromatic dispersion: a new approach (pp. 19 31) sukkur iba journal of emerging technologies sjet | vol. 5 no. 1 january – june 2022 28 bit error rate is calculated by the sp tool of matlab. the semianalytic type model is selected in which eb/no range is 0:19 db, channel is optical fiber, modulation is 16qam and samples per symbols are 256. after that response of chromatic dispersion mitigation is generated via eye-diagram that is generated via gui as shown in fig. 14. fig. 14. the response of gui for generating the eye diagram for performing mitigation of chromatic dispersion it is really important to shows the original signal which is transmitted at optical fiber channel. if the designed system was not developed. every time have to execute simulation and programming need to be dine for that. the response of signal transmitted can be easily developed and displayed via gui as shown in fig. 15. fig. 15. response of gui for input signal to be transmitted similarly, the gui has the capability to generate the response and difference between the signals transmitted and signal that is corrupted via chromatic dispersion. the response of noisy signal due to chromatic dispersion is shown in fig. 16. this shows that after propagation at fiber optic at receiver we get this noisy signal due to chromatic dispersion. fig. 16. response of gui for noisy signal received at end of fiber channel finally, after applying the proposed technique that mitigates the chromatic dispersion via our method. the final output of the signal in which chromatic dispersion is removed can be depicted as well. this is only possible due to the development of gui. the response of the output signal that is generated form which chromatic dispersion is mitigated is shown in fig. 17. in this work, the development of chromatic dispersion is carried out via digital signal processing technique i.e. raised cosine filter, window and filtration method. the gui is designed in order to ease the system designer, in terms eliminate the need of redesign and development of gui for the mitigation of chromatic dispersion: a new approach (pp. 19 31) sukkur iba journal of emerging technologies sjet | vol. 5 no. 1 january – june 2022 29 programming for each change in parameters and running whole simulation again and again. fig. 17. the response of gui for output signal after mitigation of chromatic dispersion. in the past, the work also carried out related to reducing the chromatic dispersion. alfiad m.s et al, (2009) [21], worked on digital modulation scheme in an electrical and optical chromatic dispersion compensation for low frequency. every time when changing the permanents, the re-programming of algorithm was required. cherbi l et al, (2006) [22], worked on measures cd in optical networks in which compensators is designed for certain wavelength. phase-shift modulation scheme is adopted for the measurement of cd smf for 10 km distance only. li, xu et al, (2020) [23] worked transmission systems artificial cd and dgd is compensated can be compensated but without simplifying system. goldfarb gilad and li guifang, (2007) [24] worked on digital iir filtering to control cd in system with dsp. there are less number of taps are used in iir filtering as compared in fir filtering, complex programming and no reprogramming feature was there. borjesson (2016) [25] worked on design of compensator for cd. compensator works on lookup table function along with usage of bpsk with low ber. xu tianhua, (2012) [26] worked on digital filters for compensation of cd and n improved feature recorded. from above it was concluded that in the past lack of programming, re-programming, visualization, execution of models, complex modeling, low data rate, lack of data analysis and several issues left unaddressed. taking the benefits of all that our work proposed the chromatic dispersion is carried out via digital signal processing technique for better ber performance. one of the main novelty of the work is design and development of gui that is not descripted yet in the literature. the designed provided various feature to communication system designer that reduces the efforts of programming, not only this the system characterization can be changed easily. the designed system will be helpful for many researcher those who are working on optical system as it is giving the fast and accurate way of analyzing the results. in this work, the mitigation of chromatic dispersion is carried out along with design of graphical user interface (gui). the designed offers great feature of mitigating chromatic dispersion using the less complex algorithms, better ber and eye diagram and one of the main novelty and contribution of the work is system changes in parameters and characterization is developed and designed are made ease. the existing system offering the output execution separately and changing of parameters is also challenging. in developing the gui there are many features are added such as overserving results in faster development of optical fiber channel in a gui is not done before. the designed system can be beneficial for the student’s ad researcher that are working of optical system design via this system they can design, analysis, and output can be observe. the designer can work other aspects such as developing advanced algorithm in the system. it is concluded that the designed work offer the gui in order to mitigate the chromatic dispersion from the optical systems. the system has been developed for the 10 gb/s data rate and the compensation of more than 40 % has been attained during the proposed system and the ber of 10-3 is achieved. the system is considered to be the good step as in the past discussed in literature review that no such type of gui was report. the designed system will be helpful for the optical designer and researchers as it will be great platform to demonstrate the chromatic design and development of gui for the mitigation of chromatic dispersion: a new approach (pp. 19 31) sukkur iba journal of emerging technologies sjet | vol. 5 no. 1 january – june 2022 30 dispersion compensation by configuring their system requirements and they can see the output at the same time. the authors would like thanks department of electronic engineering, quaid-e-awam university of engineering, science and technology, nawabshah, sindh, pakistan for the technical support in carrying this research work. references [1] m. f. l. abdullah, b. das, and m. s. n. shahida, "frequency domain technique for reducing chromatic dispersion," in 2014 electrical power, electronics, communicatons, control and informatics seminar (eeccis), 2014, pp. 56-61. [2] m. f. l. abdullah, b. das, and n. s. m. shah, "dsp techniques for reducing chromatic dispersion in optical communication systems," in 2014 international conference on computer, communications, and control technology (i4ct), 2014, pp. 305-309. [3] ahmed, r. k., & mahmood, h. a. (2018, january). performance analysis of pam intensity modulation based on dispersion compensation fiber technique for optical transmission system. in engineering sciences-3rd scientific conference of engineering science (isces), 2018 1st international scientific conference of (pp. 126130). ieee. [4] yang, a., guo, p., wang, w., lu, y., & qiao, y. (2019). joint monitoring of chromatic dispersion, osnr and inter-channel nonlinearity by lfm pilot. optics & laser technology, 111, 447-451. [5] amiri, i. s., rashed, a. n. z., kader, h. m. a., al-awamry, a. a., abd el-aziz, i. a., yupapin, p., & palai, g. (2020). optical communication transmission systems improvement based on chromatic and polarization mode dispersion compensation simulation management. optik, 207, 163853. [6] neumann, s. p., ribezzo, d., bohmann, m., & ursin, r. (2021). experimentally optimizing qkd rates via nonlocal dispersion compensation. quantum science and technology, 6(2), 025017. [7] wu, z., li, s., huang, z., shen, f., & zhao, y. (2021, november). chromatic dispersion equalization fir digital filter for coherent receiver. in photonics (vol. 8, no. 11, p. 478). multidisciplinary digital publishing institute. [8] udayakumar, r., khanaa, v., & saravanan, t. (2013). chromatic dispersion compensation in optical fiber communication system and its simulation. indian journal of science and technology, 6(6), 4762-4766. [9] mustafa, f. m., zaky, s. a., khalaf, a. a., & aly, m. h. (2021). dispersion compensation in silica doped fiber using soliton transmission technique over cascaded fbg. optical and quantum electronics, 53(5), 1-17. [10] galvis-velandia, j. e., puerto-lópez, k., & ramírez-mateus, j. (2021, november). analysis of linear and non-linear effects in the frequency domain for a three-channel optical transmission system. in journal of physics: conference series (vol. 2102, no. 1, p. 012017). iop publishing. [11] novick, a., castro, j. m., pimpinella, r., kose, b., huang, p., & lane, b. (2018, march). study of dispersion compensating multimode fiber for future vcsel pam-4 channels at data rates over 100 gb/s. in 2018 optical fiber communications conference and exposition (ofc) (pp. 1-3). ieee. [12] zeng, z., yang, a., guo, p., & feng, l. (2018, january). weighted finite impulse response filter for chromatic dispersion equalization in coherent optical fiber communication systems. in 2017 international conference on optical instruments and technology: optoelectronic devices and optical signal processing (vol. 10617, p. 106170u). international society for optics and photonics. [13] konishi, t., murakawa, t., nagashima, t., hasegawa, m., shimizu, s., hattori, k., ... & wada, n. (2015). flexible ofdm-based access systems with intrinsic function of chromatic dispersion compensation. optical fiber technology, 26, 94-99. [14] ranzini, s. m., parahyba, v. e., júnior, j. h. d. c., guiomar, f., & carena, a. (2019). impact of nonlinear effects and mitigation on coherent optical systems. in optical communications (pp. 93-120). springer, cham. [15] ji, j., zheng, s., & zhang, x. (2019). predistortion compensation for optical-based broadband lfm signal generation system. optics communications, 435, 277-282. [16] fu, s., chen, c., gao, f., li, x., deng, l., tang, m., & liu, d. (2018). digital chromatic dispersion pre-management enabled single-lane 112 gb/s pam-4 signal transmission over 80 km ssmf. optics letters, 43(7), 1495-1498. [17] kumar, p., kumar, v., & roy, j. s. (2019). design of quad core photonic crystal fibers with flattened zero dispersion. aeu-international journal of electronics and communications, 98, 265-272. [18] hu, y., wang, y., & chee, k. w. (2019). optical communications and modulation techniques in 5g. in smart grids and their communication systems (pp. 401-464). springer, singapore. [19] nain, h., jadon, u., & mishra, v. (2018). performance exploration of different dispersion compensation schemes with binary and duo binary modulation formats over fiber-optic communication. in information and communication technology for sustainable development (pp. 281-290). springer, singapore. design and development of gui for the mitigation of chromatic dispersion: a new approach (pp. 19 31) sukkur iba journal of emerging technologies sjet | vol. 5 no. 1 january – june 2022 31 [20] sharma, d., & prajapati, y. k. (2018). analytical study of dwdm optical long haul network with symmetrical dispersion compensation. indian journal of science and technology, 8(1). [21] alfiad, m. s., van den borne, d., jansen, s. l., wuth, t., kuschnerov, m., grosso, g., ... & de waardt, h. (2009). a comparison of electrical and optical dispersion compensation for 111-gb/s polmux–rz–dqpsk. journal of lightwave technology, 27(16), 3590-3598. [22] cherbi, l., azrar, a., mehenni, m., & aksas, r. (2009). characterization of the polarization in the spun fibers. microwave and optical technology letters, 51(3), 725-731. [23] liu, x., lun, h., fu, m., fan, y., yi, l., hu, w., & zhuge, q. (2020). ai-based modeling and monitoring techniques for future intelligent elastic optical networks. applied sciences, 10(1), 363. [24] goldfarb, g., & li, g. (2007). chromatic dispersion compensation using digital iir filtering with coherent detection. ieee photonics technology letters, 19(13), 969-971. [25] börjesson, e. (2018). implementation of blind carrier phase recovery for coherent fiber-optical receivers (master's thesis). [26] xu, t., karanov, b., shevchenko, n. a., lavery, d., liga, g., killey, r. i., & bayvel, p. (2017). digital nonlinearity compensation in high-capacity optical communication systems considering signal spectral broadening effect. scientific reports, 7(1), 1-10 [27] kaim khani, t., mushtaq, z., waqas, a., chowdhry, b. s., & uqaili, m. a. (2021). improving vlc data rate and link range using commercial electronic components. wireless personal communications, 1-13. [28] shaikh, m. n., waqas, a., chowdhry, b. s., & umrani, f. a. (2012). performance and analysis of fso link availability under different weather conditions in pakistan. journal of the institution of electrical & electronics, 76, 1-5. [29] arain, s., shaikh, m. n., waqas, a., chowdhry, b. s., & themistos, c. (2016, july). performance analysis of advance modulation schemes for free space optical networks. in 2016 18th international conference on transparent optical networks (icton) (pp. 1-4). ieee. [30] mushtaq, z., uqaili, m. a., waqas, a., & chowdhry, b. s. (2021). multi-stage mach– zehnder based continuously tunable photonic delay line. wireless personal communications, 111. vol. 3, no. 1 | january june 2020 sjet | issn: 2616-7069 | vol. 3 | no. 1 | © 2020 sukkur iba university 55 static analysis of six bar tensegrity ball structure robot muhammad basit chandio1, ani luo1, asif raza1, sanaullah khushak1, muhammad nazim lakhan2, altaf hussain shar2, kishore chand2, fahad hussain3, zubair ali shah4 abstract: all pre-stressed structures called as tensegrity structures have been introducing into robotics, modern architectural designs, and medical necessities called bio-tensegrity, space structure alternates, and many other emerging technologies because of its numerous useful properties. six bar tensegrity ball robot structure has an essential importance in the field of robotics due to its deployable, movable, deformable, and easily controllable capabilities. this structure has 6 rigid bars (in compression) and 24 flexible strings (in tension) that are connected in such a 12 nodes arrangement that provides the highest spatial symmetrical shape to this structure among most of the tensegrity structure. in this paper, the internal forces of bars and strings on each node have been studied, and the force equation on every node has been developed. furthermore, the balance of all bars and strings forces on the whole structure has been analytically verified to assure the structure remains statically pre-stressed under the zero net effect of all internal forces applied by bars and strings. keywords: static analysis; force equations; equilibrium 1. introduction tensegrity structures are formed by a combination of rigid elements (the bars) and elastic elements (the strings) [1-4]. the bars are always in compression and the strings in tension. the entire structure stands by itself and maintains its form solely because of the internal arrangement of the strings and the bars [5-8]. tensegrity structures were used only in arts and architecture in the early1960s 1 college of mechanical & electrical engineering, harbin engineering university, harbin, china 2college of material science and chemical engineering, harbin engineering university, harbin, china 3department of mechanical engineering muet szab campus khairpur mir's, pakistan 4college of power & energy engineering, harbin engineering university, harbin, china corresponding author: basitchandio47@gmail.com when fuller coined this tensegrity idea [9-12]. orthopedic surgeon stephen levin found a tensegrity structure could be a new biomechanical approach and coined a biotensegrity term in the medical field in the 1970s[13], later these structures have been remaining a vital part in medical researches[14-17]. tensegrity structures are also used in robotics because of implement flexibility, dynamism, and light-weighting chandio m.b (et al.), static analysis of six bar tensegrity ball structure robot (pp. 55 – 67) sjet | issn: 2616-7069 | vol. 3 | no. 1 | © 2020 sukkur iba university 56 [18-21]. these structures are also used in space applications due to super deplorability [22, 23]. louani modeled the mathematics of the six-bar tensegrity ball structure robot[24] and analyzed the possible and feasible ways to drive this structure [25-27]. nasa proposed a six-bar tensegrity ball robot structure as workable in landing on different surfaces for planetary exploration missions and easy to move and control the structure [28, 29]. it is vital to recognize the all internal forces exerted by all bars and strings on each node of six-bar tensegrity ball structure robot in a static position in order to move it by servomotors or to land it for planetary exploring mission to protect the payload. skelton in his book and julio in his paper have mentioned basic general methods to analyze the static tensegrity structures [30, 31]. but, there is a gap of static analysis of the six-bar tensegrity ball structure robot in research. here, a static study of the six-bar tensegrity ball structure has been done to analyze the position and forces exerted by all bars and strings on each node and the overall net effect of all internal forces of the structure has been observed to verify the static mode of structure. in this paper, a six-bar tensegrity ball structure robot has been defined and a node matrix has been developed. later, individual force equations for all nodes have been established. in the last, all individual force equations on each node have been examined to validate the static position of the structure by balancing the bars forces and strings forces. 2. introduction of the six bar tensegrity ball robot structure six bar tensegrity ball robot structure has 6 rigid bars in compression and 24 flexible strings in tension. all bars are shown by blue color and strings are shown by red color and are connected by 12 nodes. each node is connected with one bar and four strings. in this structure, all six bars are lying along three different planes. each plane has two parallel bars. bars b1 & b2 lay along xy plane, bars b3 & b4 lay along yz plane and bars b5 & b6 lay along xz plane. similarly nodes1,2,3 & 4 are in xy plane, nodes 5,6,7 & 8 are in yz plane and nodes 9,10,11 & 12 are in xz plane as illustrated in fig.1. fig. 1. six bar tensegrity ball structure robot illustrated (a) in matlab & (b) in adams all members of six-bar tensegrity structure are connected by 12 nodes and a node ni can be represented in cartesian coordinates as n = n n n ,i 1,12i ix iy iz        (a) group i strings group ii strings group iii strings b1 & b2 in xoy b3 & b4 in yoz b5& b6 in zox (b) chandio m.b (et al.), static analysis of six bar tensegrity ball structure robot (pp. 55 – 67) sjet | issn: 2616-7069 | vol. 3 | no. 1 | © 2020 sukkur iba university 57 node matrix (n) can be obtained by putting all nodes in a column of the matrix. = n , n , n ...n 1 2 3 12 3×12     n coordinates of all 12 nodes along three axes can be rearranged as displayed in eq. (1) [24]. 5 71 2 3 4 6 8 9 10 11 12 0.5 0.5 0.5 0.5 0 0 0 0 0.5 0.5 0.5 0.5 3 12 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0 0 0 0 r 0 0 0 0 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 n n n n n n n n n n n n l l l l l l l l b b b b d d d d n l l l l l l l l d d d d b b b b l l l l l l l l d d d d b b b b                          (1) 3. internal forces on structure every node of the six-bar tensegrity ball structure is acted by four strings forces and one bar force. we have modeled separate equations of forces for each node in all three axes. force density in strings is the tension applied string per unit its length (i-e: γ=ts/ls) and force density by the bar is the force applied by bar per unit its length (i-e: λ=fb/lb) [24, 30]. six bar tensegrity structure is spatial structure and lies along three space axes. each plane contains four nodes. 3.1. internal forces on nodes laying along xy plane plane xy contains four nodes 1, 2, 3 & 4. we find the force equations of each node. here, node 1 is connected with strings s1, s2, s3, s4 & bar b1 in such an arrangement that strings pull the node inwards and bar pushes it back by the forces ts1, ts2, ts3, ts4 & fb1 respectively, but the node does not move in any direction as shown in fig.2. fig. 2. forces on node 1 0 1 2 3 41 f t t t ts s s sb      (2) as we already mentioned λ=fb/lb & γ=ts/ls in section 3, therefore, by putting substitutes of bar force and all string forces in terms of force densities in eq. (2), we achieve n9 n5 n2 n 7 n10 chandio m.b (et al.), static analysis of six bar tensegrity ball structure robot (pp. 55 – 67) sjet | issn: 2616-7069 | vol. 3 | no. 1 | © 2020 sukkur iba university 58 (n ) (n ) (n ) (n ) (n ) 0 5 71 1 2 1 1 2 1 3 9 1 4 10 1 n n n n n               all bars have the same force density as λ, and all strings have the same force density as γ when no external force acts on the structure. we get eq. (4) by putting coordinates of nodes in eq. (3) force equations along the x-axis and y-axis on node 1 are eq. (5) & eq. (6) respectively and force equation along the z-axis is zero. (l ) ( 2 ) 0l l b d b      (5) ( 2 ) 0l l b d    (6) eq. (5) & eq. (6) are force equations in terms of force densities, bars length, and the perpendicular distance between two parallel bars. similarly, we find force equations on node 2. this node is connected with strings s5, s6, s7, s8 & bar b1 in such an arrangement that strings pull the node inwards and bar pushes it back by forces ts5, ts6, ts7, ts8 & fb1 respectively, but this node does not move in any direction also as illustrated in fig. 3. fig 3. forces on node 2 (n ) (n ) (n ) (n ) (n ) 0 5 5 7 71 2 1 2 6 2 11 2 8 12 2 n n n n n               4 5 7 9 10 11 2 4 0 5 71 2 9 10 1 41 2 5 7 9 10 1 n n n n nn nx x x x x x x n n n n n n ny y y y y y y n n n n n n nz z z z z z z                                   0.5 ( 0.5 ) 0 0 0.5 0.5 4 0.5 0.5 0.5 0.5 0.5 0 0 4 0.5 0 0 0 0.5 ( 0.5 ) 0.5 ( 0.5 ) 4 0 l l l l l b b d d b l l l l l d d b b d l l l l d d b b                                         n1 n 5 n 7 n 11 n 12 (3) (4) chandio m.b (et al.), static analysis of six bar tensegrity ball structure robot (pp. 55 – 67) sjet | issn: 2616-7069 | vol. 3 | no. 1 | © 2020 sukkur iba university 59 0 5 76 81 f t t t ts s s sb      (7) similarly, by putting substitutes of bar force and all string forces in terms of force densities eq. (7), we achieve (n ) (n ) (n ) (n ) (n ) 0 5 5 7 71 2 1 2 6 2 11 2 8 12 2 n n n n n               all bars have the same force density as λ, and all strings have the same force density as γ when no external force acts on structure, therefore ( ) ( 4 ) 0 5 72 1 11 12 2 n n n n n n n         4 5 7 11 12 22 1 4 0 5 72 1 11 12 2 42 1 5 7 11 12 2 n n n n nn nx x x x x x x n n n n n n ny y y y y y y n n n n n n nz z z z z z z                                   (8) we get eq. (9) by putting coordinates of nodes in eq. (8) ( 0.5 ) 0.5 0 0 ( 0.5 ) ( 0.5 ) 4 ( 0.5 ) 0.5 0.5 0.5 0.5 0 0 4 0.5 0 0 0 0.5 ( 0.5 ) 0.5 ( 0.5 ) 4 0 l l l l l b b d d b l l l l l d d b b d l l l l d d b b                                            (9) force equations along the x-axis and yaxis on node 2 are in eq. (10) & eq. (11) respectively and force equation along the zaxis is zero ( ) ( 2 ) 0l l l b d b        (10) ( 2 ) 0l l b d    (11) eq. (10) & eq. (11) are force equations in terms of force densities, bars length, and the perpendicular distance between two parallel bars. again, node 3 is connected with strings s9, s10, s11, s12 & bar b2 in such an arrangement that strings pull the node inwards and bar pushes it back by forces ts9, ts10, ts11, ts12 & fb2 respectively, but this node also does not move in any direction as shown in fig. 4. fig. 4. forces on node 3 n 8 n 1 n 6 n 9 n 4 chandio m.b (et al.), static analysis of six bar tensegrity ball structure robot (pp. 55 – 67) sjet | issn: 2616-7069 | vol. 3 | no. 1 | © 2020 sukkur iba university 60 0 9 10 11 122 f t t t ts s s sb      (12) similarly, by putting substitutes of bar force and all string forces in terms of force densities eq. (12), we achieve all bars have the same force density as λ and all strings have the same force density as γ when no external force acts on structure, therefore 0(n n ) + (n + n + n + n 4n ) = 43 6 8 9 10 3   4 3 4 6 8 9 10 3 4 0 3 4 6 8 9 10 3 43 4 6 8 9 10 3 n n n n n n nx x x x x x x n n n n n n ny y y y y y y n n n n n n nz z z z z z z                                    (13) we get eq. (14) by putting coordinates of nodes in eq. (13) 0.5 ( 0.5 ) 0 0 0.5 0.5 4 (0.5 ) 0.5 ( 0.5 ) 0.5 ( 0.5 ) 0 0 4 ( 0.5 ) 0 0 0 0.5 ( 0.5 ) 0.5 ( 0.5 ) 4 0 l l l l l b b d d b l l l l l d d b b d l l l l d d b b                                              (14) force equations along the x-axis and yaxis on node 3 are in eq. (15) & eq. (16) respectively and force equation along the zaxis is zero ( ) ( 2 ) 0l l l b d b      (15) ( 2 ) 0l l b d     (16) eq. (15) & eq. (16) are force equations in terms of force densities, bars length, and the perpendicular distance between two parallel bars. likewise, node 4 is connected with strings s13, s14, s15, s16 & bar b2 in such an arrangement that strings pull the node inwards and bar pushes it back by forces ts13, ts14, ts15, ts16 & fb2 respectively, but the node does not move in any direction as illustrated in fig. 5. fig 5. forces on node 4 0 2 9 10 11 12 (n n ) + (n n ) + (n n ) + (n n ) + (n n ) = 43 6 3 8 3 9 3 10 3      n 3 n 6 n 1 n 1 n 8 chandio m.b (et al.), static analysis of six bar tensegrity ball structure robot (pp. 55 – 67) sjet | issn: 2616-7069 | vol. 3 | no. 1 | © 2020 sukkur iba university 61 0 13 14 15 162 f t t t ts s s sb      (17) similarly, by putting substitutes of bar force and all string forces in terms of force densities eq. (17), we achieve all bars have the same force density as λ, and all strings have the same force density as γ when no external force acts on structure, therefore 4 3 11 4 (n n ) + (n + n + n + n 4n ) = 0 6 8 12   4 4 3 6 8 11 12 4 4 0 4 3 6 8 11 12 4 44 3 6 8 11 12 4 n n n n n n nx x x x x x x n n n n n n ny y y y y y y n n n n n n nz z z z z z z                                    (18) we get eq. (19) by putting coordinates of nodes in eq. (18) ) ( ) ) ) 0.5 0.5 0 0 0.5 0.5 4 ( 0.5 0.5 0.5 0.5 ( 0.5 0 0 4 ( 0.5 0 0 0 0.5 ( 0.5 ) 0.5 ( 0.5 ) 4 0 d d d d d d d b b b b b b b l l l l l l l l l l l l l l                                              (19) force equations along the x-axis and yaxis on node 4 are in eq. (20) & eq. (21) respectively and force equation along the zaxis is zero ( ) ( 2 ) 0l l l b d b        (20) (20) ( 2 ) 0l l b d     (21) (21) eq. (20) & eq. (21) are force equations in terms of force densities, bars length, and the perpendicular distance between two parallel bars. 3.2. internal forces on nodes laying along yz plane plane yz also contains four nodes 5, 6, 7 & 8. here in this section, we just put the force equations on each node lying in the yz plane, and these equations can be found with the same method used in section 3.1. here, node 5 is connected with four strings s1, s5, s17, s18 & one bar b3 in such an arrangement that strings pull the node inwards and bar pushes it back by forces ts1, ts5, ts17, ts18 & fb3 respectively, but the node does not move in any direction as shown in fig. 6 0 51 17 183 f t t t ts s s sb      (22) we found force equations in terms of force densities, bars length, and the perpendicular distance between two parallel bars along the y-axis and z-axis on node 5 in 2 4 3 13 4 14 4 14 11 4 15 4 0 6 8 12 (n n )+ (n n )+ (n n )+ (n n )+ (n n )=     chandio m.b (et al.), static analysis of six bar tensegrity ball structure robot (pp. 55 – 67) sjet | issn: 2616-7069 | vol. 3 | no. 1 | © 2020 sukkur iba university 62 eq. (23) & eq. (24) respectively and force equation along the x-axis as zero. ( ) ( 2 ) 0l l l b d b      (23) ( 2 ) 0l l b d    (24) fig. 6. forces on node 5 similarly, ts9, ts13, ts19, ts20 & fb3 are forces exerted by four strings s9, s13, s19, s20 & one bar b3 on node 6 in such manner that strings pull the node inwards and bar pushes it back and the node does not move in any direction as shown in fig. 7. 0 9 13 19 203 f t t t ts s s sb      (25) we found force equations in terms of force densities, bars length, and the perpendicular distance between two parallel bars along the y-axis and z-axis on node 6 as in eq. (26) & eq. (27) respectively and force equation along the x-axis as zero. ( ) ( 2 ) 0l l l b d b        (26) ( 2 ) 0l l b d    (27) four strings s2, s6, s21, s22, & one bar b4 exert forces ts2, ts6, ts21, ts22 & fb4 respectively one node 7 in such manner that this node has no movement in any direction as shown in fig. 8. fig. 7. forces on node 6 fig. 8. forces on node 7 0 2 6 21 224 f t t t ts s s sb      (28) n 9 n 1 n 6 n 1 n 2 n 3 n 5 n 4 n 9 n 1 n 1 n 2 n 10 n 12 n 8 chandio m.b (et al.), static analysis of six bar tensegrity ball structure robot (pp. 55 – 67) sjet | issn: 2616-7069 | vol. 3 | no. 1 | © 2020 sukkur iba university 63 we found force equations in terms of force densities, bars length, and the perpendicular distance between two parallel bars along the y-axis and z-axis on node 7 as in eq. (29) & eq. (30). moreover, the force equation along the x-axis is zero. ( ) ( 2 ) 0l l l b d b      (29) ( 2 ) 0l l b d     (30) similarly, node 8 is balanced by forces ts10 ,ts14 ,ts23 , ts24 & fb4 applied by four strings s10, s14, s23, s24 & one bar b4 as shown in fig.9. fig. 9. forces on node 8 0 10 14 23 244 f t t t ts s s sb      (31) we found force equations in terms of force densities, bars length, and the perpendicular distance between two parallel bars along the y-axis and z-axis on node 8 as in eq. (32) & eq. (33) respectively and force equation along the x-axis is zero. ( ) ( 2 ) 0l l l b d b        (32) ( 2 ) 0l l b d     (33) 3.3. internal forces on nodes laying along xz plane plane xz also contains four nodes 9, 10, 11 & 12. here in this section, we just put the force equations on each node lying in the xz plane, and these equations can be found with the same method used in section 3.1. so, node 9 is connected with four strings s10, s14, s23, s24 & one bar b5 in such an arrangement that strings pull the node inwards and bar pushes it back by the forces ts10, ts14, ts23 , ts24 & fb5 respectively but node remains in the same position as shown in fig.10. fig 10. forces on node 9 0 3 11 17 195 f t t t ts s s sb      (34) we found force equations in terms of force densities, bars length, and the perpendicular distance between two parallel bars along the x-axis and z-axis on node 9 as n 7 n 10 n 3 n 4 n 12 n 5 n 10 n 1 n 6 n 3 chandio m.b (et al.), static analysis of six bar tensegrity ball structure robot (pp. 55 – 67) sjet | issn: 2616-7069 | vol. 3 | no. 1 | © 2020 sukkur iba university 64 in eq. (35) & eq. (36) respectively and force equation along the y-axis as zero. ( 2 ) 0l l b d    (35) ) ( 2 ) 0l l l b d b      (36) similarly, four strings s4, s12, s21, s23, & one bar b5 apply forces ts4, ts12, ts21, ts23 & fb5 respectively on node 10 in such manner that node does not move in any direction as shown in fig. 11. fig. 11. forces on node 10 0 4 12 21 235 f t t t ts s s sb      (37) we found force equations in terms of force densities, bars length, and the perpendicular distance between two parallel bars along the x-axis and z-axis on node 10 as in eq. (38) & eq. (39) respectively and force equation along the y-axis as zero. ( 2 ) 0l l b d    (38) ) ( 2 ) 0l l l b d b       (39) node 11 is connected with strings s7, s15, s18, s20, & b6 in such an arrangement that strings pull the node inwards and bar pushes it back ts7, ts15, ts18 , ts20 & fb6 respectively, but the node does not move in any direction as illustrated in fig.12. fig. 12. forces on node 11 we found force equations in terms of force densities, bars length, and the perpendicular distance between two parallel bars along the x-axis and z-axis on node 11 as in eq. (41) & eq. (42) respectively and force equation along the y-axis as zero. ( 2 ) 0 b d l l    (41) ) ( 2 ) 0l l l b d b      (42) finally, node 12 is pulled by forces ts8, ts16, ts22 , ts24 applied by four strings s8, s16, s22, s24, and pushed back by force fb6 applied 0 7 15 18 206 f t t t ts s s sb      (40) n 5 n 4 n 2 n 12 n 6 n 7 n 9 n 1 n 3 n 8 ts4 chandio m.b (et al.), static analysis of six bar tensegrity ball structure robot (pp. 55 – 67) sjet | issn: 2616-7069 | vol. 3 | no. 1 | © 2020 sukkur iba university 65 by bar b6, but the node does not experience any movement in any direction as shown in fig.13. fig. 13. forces on node 12 0 8 16 22 246 f t t t ts s s sb      (43) we found force equations in terms of force densities, bars length, and the perpendicular distance between two parallel bars along the x-axis and z-axis on node 12, as in eq. (44) & eq. (45) respectively and force equation along the y-axis as zero. ( 2 ) 0l l b d     (44) ) ( 2 ) 0l l l b d b       (45) 3.4. internal force on the whole structure we have found force equations of all 12 nodes along three axes individually. here, we add all these force equations to analyze overall force along each axis on the whole structure. we got net force as zero by adding all force components along the x-axis of all nodes as follows: (l ) ( 2 ) ( ) ( 2 ) ( ) ( 2 ) ( ) ( 2 ) ( 2 ) ( 2 ) ( 2 ) ( 2 ) 0 l l l l l l l l l b d b b d b b d b b l l l l l l l l l l d b b d b d b d b d                                      (46) similarly, we get net force as zero by adding all force components along the y-axis of all nodes as follows ( 2 ) ( 2 ) ( 2 ) ( 2 ) ( ) ( 2 ) ( ) ( 2 ) ( ) ( 2 ) ( ) ( 2 ) 0 l l l l l l l l l l l b d b d b d b d b d b l l l l l l l l l b d b b d b b d b                                       (47) again, we get net force as zero by adding all force components along the z-axis of all nodes as follows n 2 n 4 n 7 n 8 n 11 chandio m.b (et al.), static analysis of six bar tensegrity ball structure robot (pp. 55 – 67) sjet | issn: 2616-7069 | vol. 3 | no. 1 | © 2020 sukkur iba university 66 ( 2 ) ( 2 ) ( 2 ) ( 2 ) ) ( 2 ) ) ( 2 ) ) ( 2 ) ) ( 2 ) 0 l l l l l l l l l l l b d b d b d b d b d b l l l l l l l l l b d b b d b b d b                                         (48) it can be analyzed by the above calculations that all internal forces exerted by rigid bars and flexible strings acting on the whole structure have no net effect along any axis, which results in the structure to remain in equilibrium, this null result of all internal forces of members on whole structure shows the all force equations developed for each node are valid. 4. conclusion we defined the structure of the six-bar tensegrity ball structure robot and developed its nodes matrix. force equations for each node were developed individually. the overall net effect of forces applied by strings and bars of the structure was investigated, and it was observed that forces applied by all strings and bars on the whole structure balance each node and form a whole spatial balanced structure. acknowledgement this research has been sponsored by the national natural science foundation of china (grant no. 51605111, 51675114, 51875111). nomenclature lb length of each bar ld distance between each couple of parallel bars fb internal force of bars ts internal force of strings λ bar force density γ string force density in group i strings after references [1] j. yin, j. duffy, and r. crane ," an analysis for the design of self-deployable tensegrity and reinforced tensegrity prisms with elastic ties". 2002. 17(1): p. 38-45. [2] fuller r b, tensile integrity structures, u.s.p. office, editor. 1959: united states. [3] otto f, tensile structures. 1967, cambridge: mit press. [4] fuller r b and applewhite e j, synergetics : explorations in the geometry of thinking. 1975, new york: macmillan. [5] r. tobie, pratt institute, ny, a report on an inquiry into the existence, formation and representation of tensile structures. 1976. [6] r. motro, tensegrity : from art to structural engineering. 2011. [7] sultan c, chapter 2 tensegrity: 60 years of art, science, and engineering, in advances in applied mechanics. 2009, elsevier. p. 69145. [8] j. cai and j. feng, form-finding of tensegrity structures using an optimization method. engineering structures, 2015. 104: p. 126132. [9] b. fuller, "tensegrity" portfolio art news annual. 1961. 4: p. 112-127. [10] k. snelson, continuous tension, discontinuous compression structures, u.s.p. 611, editor. 1965: u.s.a. [11] k.snelson, “ kenneth snelson, art and ideas,” kenneth snelson, marlborough gallery, ,new york. 2013. [12] c.r. calladine, buckminster fuller's “tensegrity” structures and clerk maxwell's rules for the construction of stiff frames. international journal of solids and structures, 1978. 14(2): p. 161-172. [13] d.s. levin, http://biotensegrity.com [14] g. scarr, biotensegrity. 2014: handspring publishing, united kingdom. [15] s. levin, "the tensegrity-truss as a model for spine mechanics: biotensegrity". journal of chandio m.b (et al.), static analysis of six bar tensegrity ball structure robot (pp. 55 – 67) sjet | issn: 2616-7069 | vol. 3 | no. 1 | © 2020 sukkur iba university 67 mechanics in medicine biology, 2002. 2(03n04): p. 375-388. [16] r. noguera, o.a. nieto, and i. tadeo, extracellular matrix, biotensegrity and tumor microenvironment. an update and overview. 2012. [17] scarr. g, biotensegrity: what is the big deal? journal of bodywork and movement therapies, 2020. 24(1): p. 134-137. [18] s.h. juan, and r.e. skelton. "dynamically stable collision avoidance for tensegrity based robots". in 2009 asme/iftomm international conference on reconfigurable mechanisms and robots. 2009. ieee. [19] m. azadi, s. behzadipour, and m. faulkner, "variable stiffness spring using tensegrity prisms". 2010. 2(4): p. 041001. [20] y. sugiyama and r. hirai," crawling and jumping by a deformable robot". 2006. 25(56): p. 603-620. [21] k. kim , a.k. agogino and a.m. agogino, rolling locomotion of cable-driven soft spherical tensegrity robots. soft robotics, 2020. [22] tibert g, "deployable tensegrity structures for space applications", in department of mechanics. 2002, kth royal institute of technology: sockholm, sweden. [23] k.garanger, r. miriam ,k.matthew, soft tensegrity systems for planetary landing and exploration. arxiv preprint:2003.10999, 2020. [24] a. luo, r. e. skelton and h. liu. "structure of the ball tensegrity robot." in 2014 ieee international conference on robotics and biomimetics (robio 2014). 2014. ieee. [25] a. luo and h. liu, "analysis for feasibility of the method for bars driving the ball tensegrity robot". journal of mechanisms and robotics, 2017. 9(5): p. 051010-0510106. [26] a. luo, h. liu and y. liu. "analyzing the driving method for the ball tensegrity robot". in 2016 ieee international conference on robotics and biomimetics (robio). 2016. [27] a. luo, h. xin, p. cao, "motion simulation of six-bar tensegrity robot based on adams. in 2016" ieee international conference on mechatronics and automation. 2016. ieee. [28] sunspiral v, george g, bruce j , "tensegrity based probes for planetary exploration: entry, descent and landing (edl) and surface mobility analysis". international journal of planetary probes, 2013. 7: p. 13. [29] vespignani m, and friesen j," design of superball v2, a compliant tensegrity robot for absorbing large impacts". 2018 ieee/rsj international conference on intelligent robots and systems, ed. a.a. maciejewski, et al. 2018, new york: ieee. 2865-2871. [30] r.e. skelton and m.c. de oliveira, tensegrity systems. vol. 1. 2009: springer. [31] c.d.crane , j. duffy, and j.c. correa, static analysis of tensegrity structures. journal of mechanical design, 2005. 127(2): p. 257268. format template vol. 1, no. 1 | january june 2018 sjet | p-issn: 2616-7069 |e-issn: 2617-3115 | vol. 4 no. 1 january – june 2021 45 evaluation of oil-based power generation of pakistan. swot-delphi approach sikander ali abbasi1,2, khanji harijan2, irfan ahmed abbasi1, ayaz hussain3, 1department of energy & environment engineering, dawood university of engineering & technology, karachi, pakistan 2department of mechanical engineering, mehran university of engineering & technology, jamshoro, pakistan 3college of information and communication engineering, sungkyunkwan university, suwon, south korea 4department of electronic engineering, dong-a university, busan, south korea abstract: pakistan is heavily dependent on imported fuel for power generation. depending on imported fuel has not only increased greenhouse gas emissions (ghg) emissions, but it has also put a burden on the national exchequer and raised apprehensions on energy security. this paper thus investigates the consequences of oil-based power generation on the economy, environment, and energy security of pakistan. the strength, weakness, opportunity, and threat (swot)-delphi approach has been adopted. the study discovered that the use of imported oil for power generation is detrimental to the economy, environment, and energy security of pakistan. it further suggests that pakistan should immediately abandon oil-based power generation and explore green energy alternatives for its sustainable economic growth. this study uses a hybrid model that combines swot analysis with the delphi method. keywords: oil-based power plants, pakistan, swot analysis, energy security 1. introduction a third of energy resources in the form of oil, coal, and liquefied natural gas (lng) is imported by pakistan. an import-driven power generation policy has not only impacted the national economy but have made the energy mix unsustainable and insecure for pakistan. moreover, it has put pressure on foreign exchange reserves, subjected the economy to international energy price shocks, and put the entire economy at risk through inflation. increased inflation has considerably reduced the competitiveness of the country’s exports, further restricting the economy’s capacity to pay for energy imports [1]. the import bill of oil costing about 8.4 billion us$ is 70% of the total import bill of petroleum products [2]. the major oil exporters in the world with their share are given in table i [3]. it can be noticed from table ii that the electricity production oil has decreased substantially from 18.7% in 1975 to 3.28% in 2015. energy consumption by oil source in pakistan has also decreased over the years however, the energy production from oil increased from the year 2005 to 2015. the zuhaibuddinbhutto4 syed ali raza shah5 5mechanical engineering department, balochistan university of engineering and technology, khuzdar mailto:abbasisikandar12@gmail.com mailto:khanji.harijan@faculty.muet.edu.pk mailto:irfanahmedabbasi@hotmail.com mailto:engr_ayaz@yahoo.com sikander ali abbasi (et al.), evaluation of oil-based power generation of pakistan. swot-delphi approach (pp. 45 58) sukkur iba journal of emerging technologies sjet | vol. 4 no. 1 january – june 2021 46 energy consumption by oil is given in table iii [3]. table i. countries with largest oil reserves in 2018. country reserves (billion barrels) share (%) venezuela 303 18 saudi arabia 298 17 canada 167 10 iran 156 9 iraq 147 9 russia 106 6 kuwait 102 6 uae 98 6 usa 61 4 libya 48 3 table ii. world share of electricity from oil (19752015) [4] year % of total 1975 18.7 1980 15.7 1985 9.1 1990 10.2 1995 8.4 2000 7.3 2005 5.75 2010 3.8 2015 3.28 table iii. electricity consumption by oil (1970-2019) year total electricity consumpt ion (twh) consum ption by oil (twh) share of electricity consumpt ion by oil (%) 1970 102 54 52.9 1980 153 60 39.2 1990 302 128 42.3 2000 480 223 46.0 2010 736 244 33.0 2019 989 251 25.3 pakistan is the sixth populous country in the world and its annual population growth rate is 2% per year. in [5], with moderate gdp, urbanization, industrialization, and an increase in per capita income, electricity consumption increased substantially in the last two decades. the annual growth rate in electricity consumption is 3.8% [6]. in addition to it, electricity consumption growth rate of domestic, commercial, agriculture, industry and others remained 6.5%, 6.4%, 1.5%, 1.9%, and 6.25% respectively [7]. the electricity growth rate is 10% annually while the capacity addition is 7% only [8]. findings of one study suggest that at a global level, energy for economic development, energy security, and climate change mitigation be perused as integrated themes since there are linkages among these three agendas [9]. various governments in pakistan could not anticipate the increase in electricity demand, resultantly pakistan witnessed a shortfall of around 5000 mw of electricity over the last decade. the slow generation capacity addition was due to shortsightedness, financial constraints, and delayed policies on implementation levels [10]. however, pakistan encouraged the private sector to invest in the power sector which resulted in a considerable increase in power generation capacity. though the gap between supply and demand is over however due to shortage of indigenous natural gas, nonpayment of dues to independent power producers (ipps), the country continues to suffer from load shedding. the shortfall in the last decade hindered the economic development in terms of closure of industries, unemployment of 0.535million people, 2.5% of gdp loss, and loss of export of about 1.3 billion us dollars. dependence on imported fossil fuels has not only increased the cost of the generation, but it has also led to increase in greenhouse gas (ghg) emissions and made country susceptible to energy insecurity. to meet the electricity demand adequately, the first power policy was announced in 1994. the main features of policy are given as: • private parties could propose a site, choice of technology, and fuel type to be used for generating plants. • water and power development authority (wapda) and k-electric were made bound to buy power from independent power producers (ipps) under the long-term purchase agreements. sikander ali abbasi (et al.), evaluation of oil-based power generation of pakistan. swot-delphi approach (pp. 45 58) sukkur iba journal of emerging technologies sjet | vol. 4 no. 1 january – june 2021 47 • upfront bulk power tariff was introduced for private investors. • for thermal power plants, built-onoperate (boo) was followed. • draft security agreement was made flexible by the government of pakistan. • guaranteed availability of foreign exchange. • the 40% of capital cost shall be made available by the government of pakistan. the core objective of this power policy was to attract ipps in the electricity sector of pakistan. power policy 1994 framework predominantly resulted in private investment in oil and gas-fired power plants mainly based on imports. this policy framework provided almost blanket exemptions from all duties and taxes [11]. the root cause of the crisis could be traced back to the power policy of 1994 which significantly altered the electricity mix in subsequent years [12]. the above power policy indicates that the ipps took advantage of incentives and commissioned power plants based on imported fuels. the upward trend of oil price in the international market has damaged the economies of developing countries including pakistan. the rising trend of oil prices slow down the gdp, increased inflation, and affected the balance of payments. the direct result of high oil prices on an economy is realized through the worsening of payments and resultant shrinking of the economy [13]. the fundamental factor responsible for the electricity crisis in pakistan is its increased reliance on imported furnace oil and lack of diverseness in the electricity generation mix. the higher dependence on furnace oil is responsible for the increased cost of generation due to expensive imported fuel [14]. even in subsequent power policies, expediency was given priority over sustainability. to meet increased electricity demand, thermal power plants were commissioned, and it was assumed as an immediate solution to the energy crisis. globally use of oil for power generation has decreased due to its price uncertainty, uncertain availability due to the geopolitical situation, and environmental implications. in this backdrop, the evaluation of oil-based power generation has been undertaken considering three parameters namely energy security, economic viability, and environmental sustainability. since these three parameters are prominent in the literature and are closely interconnected with each other therefore these have been considered. various studies have defined these themes in the literature however most prominent definitions are explained in the subsequent paragraph. one such study has defined energy security as an adequate and reliable supply of energy resources at a reasonable price [1]. as per the definition of the international energy agency (iea), energy security is “uninterrupted availability of energy sources at an affordable price”. economic viability is an evaluation of various economic effects that may result from the implementation of a particular project. according to the united nations (un), world commission on environment and development environmental sustainability is about acting in a way that ensures future generations have the natural resources available to live an equal, if not better, way of life as current generations [15]. the theme ‘environmental sustainability is also defined as “managing energy and resources to minimize the environmental and ecological impacts of human activities now and for future” many studies have evaluated the power generation methods and their impact on the economy, energy security, and environmental sustainability. limited literature is available on power generation evaluation with swot globally. few studies have also been undertaken on the power generation sector in pakistan. in [16], the authors reviewed and assessed the factors of strengths, weaknesses, opportunities, and threats of biomass power generation of china. they used statistical reports literature review regulation policies and case studies. with swot analysis, they provided valuable information to devise future development and potential risks associated with biomass power. in [17], they used an approach of swot analysis by investigating internal strengths, weaknesses, opportunities, sikander ali abbasi (et al.), evaluation of oil-based power generation of pakistan. swot-delphi approach (pp. 45 58) sukkur iba journal of emerging technologies sjet | vol. 4 no. 1 january – june 2021 48 and threats for the photovoltaic solar development of africa. the authors identified that africa has a great potential to exploit solar energy with the cooperation of china and international cooperation within the framework of the belt and road initiative (bri). in [18], the authors assessed the challenging outlooks for energy mix in the association of southeast asian nations (asean) stressing the impact of fossil fuel dominated outlook when compared with its ambition to move toward green energy policies using strengths, weaknesses, opportunities, and threats. the author argues that despite the brown look due to the growing surge of coal, the asian region has many advantages in offering cleaner and greener energy for its green vision. for this target to achieve, the countries need to make further efforts to promote renewable energy, energy efficiency, regional market integration, and connectivity. author links open overlay panel. in [19], the authors conducted swot analysis for turkey's energy sector and anticipated an integrated hybrid methodology using strengths, weaknesses, opportunities, and threats (swot) analysis, analytic network process (anp), and weighted fuzzy techniques for order performance by similarity and holistically examined the energy strategy substitutes and priorities. the technique recommended in this study allowed identifying relevant criteria and sub-criteria using swot analysis. in [20], the authors conducted a swot analysis of nuclear power electricity generation. he concluded that nuclear power generation along with other renewable energies is a viable option to reduce greenhouse gases. he further concluded that fossil-fueled power plants should be integrated with carbon capture and storage (ccs) technology. in [21] the authors discussed canada’s federal and provincial government’s coherence while implementing the climate and energy policies. they tried to identify the prospects and challenges of energy policy in implementation with swot analysis. in [22], the authors identified the positive and negative aspects of deploying nuclear energy in nigeria with a swot matrix. the authors reviewed nigeria’s venture into nuclear energy while considering global efforts towards nuclear security and safety. they concluded that nuclear energy can be harnessed in nigeria while maintaining global safety practices. in pakistan, swot studies on the power generation sector are few which are mainly focused on renewable energy. in [23], the authors conducted swot analysis of renewable energy of provinces of sindh and baluchistan of pakistan. fuzzy analytical hierarchy process (fuzzy ahp) has also been used. three renewable resources (wind, solar, and biomass) have been assessed as alternatives in the decision model. they found that economic and sociopolitical are the two most important criteria. they concluded that wind has ample potential to generate electricity in both provinces. in [24], the authors performed a swot analysis of renewable energy in pakistan. authors pinpointed that huge resource potential and renewable energy maps are the strengths, while poor institutional infrastructure is its weakness. the untapped potential, micro, and mini installation are few opportunities. the threats to renewable energy are the presence of competitive energy resources, policy implications, and grid connection. finally, they concluded that retainability of renewable energy is necessary for energy security and sustainability for pakistan’s power sector, such as significant advancement to attain energy security and sustainability. in [25], the authors reviewed the issues of the power generation sector in general, the role of renewable energy in the overall mix and very precisely touched the sustainable pathway with swot analysis. they summarized that pakistan has sizable reserves of coal and the opportunity to develop gas infrastructure, inefficient utilization of domestic resources, high transmission and distribution losses have been regarded as a weakness in the system. authors have pinpointed the opportunities of distributed generation and smart grid. they concluded that to protect from threats, pakistan must reduce reliance on excessive imported fuel and reduce the cost of unit generation of power. from the above studies, it is noticed that no such study on the evaluation of oil-based power generation has been undertaken in pakistan. sikander ali abbasi (et al.), evaluation of oil-based power generation of pakistan. swot-delphi approach (pp. 45 58) sukkur iba journal of emerging technologies sjet | vol. 4 no. 1 january – june 2021 49 secondly, this study has quantitatively evaluated the drivers and barriers of oil-based power generation with the rii analysis tool. this approach has enabled us to quantify the most prominent positive and negative parameters responsible for oil-based power generation. however, the decision-makers are required to consider a substantial amount of data concerning the internal strengths and weaknesses of the oil-based power generation methods as well as external opportunities and threats. the method and results of this study could be useful for future energy policies within pakistan and other countries with similar energy demand patterns. the organizational structure of this paper is such that methodology is given in section 2. the results and discussion part are explained in section 3. conclusions and policy implications are narrated in section 4. 2 methodology 2.1 delphiswot paradigm from the above discussion, it is evident that pakistan faces both merits and demerits in balancing its future energy mix. with capacity constraints and an uncertain sociopolitical environment, the emerging electricity generation scenario is not clear. the swot analysis of pakistan’s power generation was accompanied by the delphi approach. delphi's approach is well suited for consent building. delphi's approach helps in reaching a consensus on critical issues in a diverse environment. it is a process to decide on any ambiguous topic based on a survey of respondent’s judgment. the procedure was adopted in the delphi method during the study is given as: • draft security agreement was made flexible by the government of pakistan. • experts from the oil-based power generation source were first identified and requested to take part in the survey. experts were middle and senior managerial persons who had an adequate understanding of oil-based power generation methods. • the delphi statements were developed by the authors and pursued through various successive questionnaires. • experts were requested to give their opinion on the strengths, weaknesses, opportunities, and threats of the oilbased power generation method. • the range of participant’s opinions has been identified by the likert scale. • the extreme opinions were reevaluated by the participants in the second round. lastly, a swot strategy was formulated before the proper evaluation of the oil-based power generation. questionnaires were delivered in two rounds using multiple iterations to collect data from a panel of the selected field. the expert’s assessment was weighted by the likert scale. in this study, the likert scale was judged from 1 to 5 points as given in table iv [28]. each point’s comment was recorded. the expert’s opinion in the field of strengths, weaknesses, opportunities, and threats was calculated in descending order based on the expert’s weighted evaluation. table iv. likert scale rating point remarks 1 strongly disagree 2 disagree 3 neutral 4 agree 5 strongly agree the mostly, respondents were from academia followed by government organizations and research institutions as shown in fig. 1. sikander ali abbasi (et al.), evaluation of oil-based power generation of pakistan. swot-delphi approach (pp. 45 58) sukkur iba journal of emerging technologies sjet | vol. 4 no. 1 january – june 2021 50 fig. 1. distribution of the delphi survey participants according to their significance the feedback regarding the weightage of anticipated issues was collected by sending questionnaires online in two rounds. the names of experts were kept confidential as per the understanding before sending the questionnaire to them. the number of experts for the oil-based power generation method was varying depending on the accessibility of experts. they were contacted to reply to the questionnaire in two rounds. the response was diverse. the overall response was encouraging. based on the response received, the average of each parameter and an overall average of strengths, weaknesses, opportunities, and threats were calculated with the relative importance index (rii) tool. the number of respondents contacted for each resource and their response is given in table v. the swot investigation of oil-based power generation is given in fig 2 and discussion of strength, weakness, opportunities and threats are presented in section 3. three major themes have been considered in swot as shown in fig. 3. as per the definition of international energy agency (iea), the term energy security is defined as uninterrupted availability of energy sources at an affordable price. economy is the second theme of this study which relates with cost of production and consumption of electricity. the environmental sustainability is the management of energy and resources to minimize the environmental and ecological impacts of human activities now and for future. table v. generation sources with a response rate of experts power generatio n source number of experts contacted number of experts replied respon se rate (%) oil 60 50 83 2.2 swot analysis swot analysis permits better-structured qualitative analysis of the predefined issue, second, swot is a strategic analysis tool aimed to improve the system. hence it is more vibrant and therefore better able to identify potential revisions that improve policy strategy. the consistency of a policy can be verified by swot that involves several parallel objectives. at the same time, swot analyses have several limitations. swot analysis is often subjective even if the analysis is well structured and an agreement about its findings may be hard to attain. moreover, even if it allows us to understand the strategic axis of a policy with many objectives and complicated expected impacts, it streamlines the real problem. sikander ali abbasi (et al.), evaluation of oil-based power generation of pakistan. swot-delphi approach (pp. 45 58) sukkur iba journal of emerging technologies sjet | vol. 4 no. 1 january – june 2021 51 fig. 2. swot investigation fig. 3. swot synthesis sikander ali abbasi (et al.), evaluation of oil-based power generation of pakistan. swot-delphi approach (pp. 45 58) sukkur iba journal of emerging technologies sjet | vol. 4 no. 1 january – june 2021 52 it is important to define external and internal factors before the swot analysis is done. moreover, swot analysis is an approach allowing an industry or organization to comprehend and plan to use their strengths to exploit opportunities to recognize and mend or prevent their weaknesses and to protect against any unknown threats. since pakistan still relies on the imported oil for the generation therefore, swot analysis with delphi and rii analysis of oil-based power generation method has been conducted. 2.3 relative importance index analysis relative importance index (rii) analysis tool is used to highlight the most important attributes. rii analysis allows identifying the most important criteria based on participant's replies and it is also an appropriate tool to prioritize indicators rated on the likert scale. each point’s remark is put in the rii equation. the rii method was adopted in this study to determine the relative importance of various factors affecting the quality of attributes. the formula of rii in the literature is [26] ( ) ( ) 5 5 4 4 3 3 2 2 1 1 1 5 w n n n n n rii a n n + + + + =    where w = weighting given to by respondents (ranging from 1 to 5); a = highest weight (i.e., 5 in this case) and n = total number of respondents. 2.4 average rii analysis from the analysis of rii, it is found that the threats have got highest point and opportunities have lowest point as shown in fig. 4, which proves that oil-based power generation is not suitable for pakistan. 3 results and discussion 3.1 strengths • decades of experience➔ oil-based thermal power plants were commissioned in pakistan after the announcement of the energy power policy of 1994. more oil-based power plants were added to the energy mix of pakistan in later years by independent power producers (ipps). therefore, the country has sound experience of running these plants proficiently. the operational and maintenance issues are addressed satisfactorily. the sound knowledge and skills provide greater strengths to the successful running of such power plants. • a strong network of manpower ➔ since oil-based power plants are old in pakistan, therefore the human resource-related with this sector has profound experience and skills to tackle routine problems of oil-based power plants. the training and special sessions are also conducted at certain intervals of time therefore, there is a reasonable number of trained staff available across the country. this provides the strength to run these plants without any difficulty. • less initial cost ➔ the initial cost of oil-based thermal power plants is less as compared to hydro and nuclear plants. hence these plants are preferred over other conventional plants when the capital cost is of paramount importance. secondly, these plants take less time to complete therefore, pakistan opted for these plants owing to an acute shortage of electricity over the last decade. • baseload plants ➔ these plants can take up load on the base portion of the load curve of the power system. they are generally of large capacity. these plants run practically on block load, i.e. load that is practically constant. the load factor of these plants is high. therefore, these plants always ensure the minimum electricity supply to consumers hence ensures the reliability of the power supply in the system. table vi. rii analysis of oil based power generation strengths sikander ali abbasi (et al.), evaluation of oil-based power generation of pakistan. swot-delphi approach (pp. 45 58) sukkur iba journal of emerging technologies sjet | vol. 4 no. 1 january – june 2021 53 strongly disagree (1) disagree (2) neutral (3) agree (4) strongly agree (5) no. of respo ndents rii rii (avg) decades of experience 4 4 8 24 10 50 0.728 0.8 strong network of manpower 4 4 10 24 8 50 0.712 less initial cost 0 2 8 24 16 50 0.81 base load power plant 0 0 4 16 30 50 0.90 high power density 0 0 8 12 30 50 0.88 weaknesses strongly disagree (1) disagree (2) neutral (3) agree (4) strongly agree (5) no. of respo ndents rii rii (avg) high dependence on imported oil 4 4 8 24 10 50 0.728 0.8 lack of energy audit 4 4 10 24 8 50 0.712 price vulnerability 0 2 8 24 16 50 0.81 37% of global ghg emission is from the power industry. 0 0 4 16 30 50 0.90 high power density 0 0 8 12 30 50 0.88 opportunities strongl y disagre e (1) disagree (2) neutral (3) agree (4) strongly agree (5) no. of respon dents rii rii (avg) strong potential to invest in r&d 4 6 16 14 10 50 0.728 0.68 up gradation of existing infrastructure 2 6 14 16 12 50 0.712 international cooperation 4 14 16 12 4 50 0.81 policies that promote energy efficiency leading to job creation 2 4 12 20 12 50 0.90 sikander ali abbasi (et al.), evaluation of oil-based power generation of pakistan. swot-delphi approach (pp. 45 58) sukkur iba journal of emerging technologies sjet | vol. 4 no. 1 january – june 2021 54 threats strongl y disagre e (1) disagree (2) neutral (3) agree (4) strongly agree (5) no. of respon dents rii rii (avg) cost of transportation of oil 0 0 10 20 20 50 0.84 0.84 geopolitical instability 0 0 10 20 20 50 0.84 circular debt 0 0 10 20 20 50 0.84 high import bill 0 0 6 24 20 50 0.85 restrictions owing to ghg emissions 0 0 5 10 10 50 0.84 fig. 4. average points through rii analysis high power density ➔ these plants are large with high capacity. therefore, such plants are commissioned when electricity demand is high, and the reliability of supply is not compromised under any circumstances. since these power plants cover the base portion of the load curve, hence these plants ensure the continuous supply of power to their consumers. 3.2 weaknesses • higher dependence on imported oil ➔ higher dependence on imported oil makes power generation unsustainable. the uninterruptable oil supply is a prerequisite for a reliable supply of power to its consumers. however, the oil supply is always subjected to the external economic and political situation. moreover, the supply can be disrupted in case of any eventuality or natural catastrophe. this uncertainty causes compromise on the smooth supply of fuel, leading to disruption of power generation. • lack of energy audit ➔ a regular energy audit is regarded as the most important feature of any efficient industry. an energy audit identifies the weaknesses in the system thus paving the way for remedial measures to increase efficiency. however, pakistan’s power sector has underinvested in this area and no robust energy audit program is in place. also, management lacks motivation. as a result of lack of motivation and underinvestment, the efficiency of plants is highly compromised. with inefficient plants, the cost of electricity units also increases thus making the power supply unaffordable and unsustainable. • price vulnerability ➔ since furnace oil is imported, therefore pakistan has no control over the price of fuel. any fluctuation in price is caused by the international dynamics of the oil industry. as per the agreement between regulator and ipps, the ipps supply power on a cost-plus basis thus its adverse impacts result in the form of an increase in perunit cost of electricity. this increase in per-unit cost is partially borne by the government in the form of subsidies and by consumers. therefore, the cost fluctuation of oil always puts pressure on the national exchequer and consumers. • 37% of ghg emissions are from the power industry ➔ power plants are major sikander ali abbasi (et al.), evaluation of oil-based power generation of pakistan. swot-delphi approach (pp. 45 58) sukkur iba journal of emerging technologies sjet | vol. 4 no. 1 january – june 2021 55 contributors to ghg emissions around the globe. among them, conventional thermal power plants are mainly responsible for ghg emissions. besides ghg emissions, these plants emit toxic gases such as sox. since these plants are not considered environmentally friendly, therefore new oilbased power plants are being discouraged around the globe and the share of oil-based power plants is left with only 7% of the total energy mix. thus, environmental sustainability is compromised with the presence of oil-based power plants. 3.3 opportunities • up-gradation of existing infrastructure ➔ since most oil-based power plants are old in pakistan and without any effective energy audit program in place, therefore the plants are running on low efficiency. as a result, the cost of power produced is high along with environmental consequences. modern thermal power plants run on supercritical technology with control on environmental emissions, therefore old power plants badly need retrofitting to bring them at par with new plants. this provides an opportunity for old power plants to become more efficient, and environmentally more sustainable. • international cooperation ➔ many countries have retrofitted their conventional old power plants successfully with a profound increase in energy efficiency and controlled environmental pollution from their stacks. therefore, there is a need to learn from the experiences of other countries. with the retrofitting approach, pakistan can increase the efficiency of its oil-based thermal power plants with a substantial decrease in environmental pollution. • policies, that promote energy efficiency technologies leading to job creation ➔ energy efficiency measures have pronounced benefits in the overall operations of oil-based thermal power plants. since pakistan’s thermal power plants are old, therefore this sector has enormous opportunities to enhance efficiencies. energy efficiency measures will reduce the cost of power produced, thus relieving financial pressure on government and consumers. secondly, pollution is reduced with an increasing inefficiency. therefore, pakistan’s thermal power generation has an enormous opportunity to promote energy efficiency. investing in this area will also create job opportunities. 3.4 threats • geopolitical instability ➔ pakistan imports furnace oil from the kingdom of saudi arabia. saudi arabia is situated in an area, which has become a war zone. yemen war has jeopardized the oil installations of the kingdom. yamane rebel’s attack on saudi oil facilities has exposed the vulnerability of oil supply to importers including pakistan. a recent attack of rebels on saudi oil installations disrupted 50% oil supply in a day. rising tension between iran and saudi arabia has threatened the oil supply from refineries to its suppliers. in case of war between the two countries, the oil supply would directly hit pakistan and can pose considerable economic and electricity reliability risks. • circular debt ➔ the circular debt has emerged as a great threat to the reputation, credit rating, and economic stability of the country. it is hitting industrial development, investment in indigenous resources like coal and other energy-related projects and discouraging investors while it is leaving ipps unable to buy fuel or repay bank loans. the menace of circular debt can only be wiped out sustainably only when system inefficiencies, mismanagement, and line losses are addressed along with penetration of hydro and other renewable energy sources in the energy mix of pakistan. • high import bill ➔ pakistan spends 12 billion us dollars annually on the import of crude oil. 70% of oil is used in generating power costing prs 18 per unit. with limited resources and spending such a huge amount on oil import for power generation is a great threat to the economic stability of the country. sikander ali abbasi (et al.), evaluation of oil-based power generation of pakistan. swot-delphi approach (pp. 45 58) sukkur iba journal of emerging technologies sjet | vol. 4 no. 1 january – june 2021 56 moreover, the cost of power production goes high and becomes highly uncompetitive. • restrictions owing to ghg emissions ➔ out of total ghg emissions, the share of co2 emission from the power sector is 50% [27]. in 2016, the co2 emissions were 155.27mt of co2 [28]. being the signatory of international climate protocols, pakistan must comply with international agreements. unchecked ghg emissions can put penalties in the future which will increase externality costs. therefore, pakistan will have to phase out oil-based thermal power plants to enhance the sustainability of the overall power generation sector. 4 conclusion and policy implications based on the swot-delphi model and the rii analysis as given in table vi, it is found that despite the established infrastructure of oilbased power generation, pakistan’s economy, energy security, and environmental sustainability are vulnerable. from the rii analysis, it is also evident threats with 0.84 points are more than the strengths with 0.8 points. the main threats are circular debt, geopolitical instability, high import bill, and ghg emissions. with these shortcomings alongside heavy borrowing from international banks and agencies, the country suffers from direct foreign investment in the power sector. therefore, the country needs to revisit its energy policies to attain energy security and environmental sustainability. pakistan will continue to suffer from chaos and uncertainty in the power sector unless some concrete steps in addition to the above are taken as stated below. • renewable energy technologies must be penetrated in the energy mix of pakistan. • there is a need to upgrade the infrastructure of the power system. • the highest priority is given to the privatization of distribution companies. • an effective energy efficiency policy may be implemented. • utilization of indigenous coal with high efficiency and low emission (hele) technologies for electricity production. • there is a need to minimize transmission and distribution losses. • a culture of energy conservation may be introduced in all sectors. according to enercon, there is a 17% saving potential of energy. • bringing the energy sector under a single managing authority will bring about significant improvement in the system. • there is a need to learn from the experiences of other countries. • reduction of losses through a microgrid and smart grid may be initiated. • the utilization of the potential of pakistan shell gas reserves (105 tcf) can also be a positive move. pakistan has shell oil reserves (9.1 billion barrels). this is a viable option for pakistan. • integrated energy modeling and planning mechanism needs to be incorporated into a policy framework. • development of integrated gis framework for the energy sector. therefore, there is an urgent need to take the above steps to shape the power sector in such a way that ensures sustained economic growth, energy security, and environmental sustainability. data availability statement we state that we have not taken data from any database. this data is taken from a field survey. this data is available in the directorate of postgraduate studies, mehran university of engineering & technology, jamshoro. author contribution all authors contributed equally to the work. sikander ali abbasi (et al.), evaluation of oil-based power generation of pakistan. swot-delphi approach (pp. 45 58) sukkur iba journal of emerging technologies sjet | vol. 4 no. 1 january – june 2021 57 conflict of interest the authors declare no conflict of interest. fundng not applicable acknowledgment the authors are highly indebted to their respective universities to provide all assistance and resources to complete this work. references [1] s. malik, m. qasim, h. saeed, y. chang, f. t. hesary, "energy security in pakistan: a quantitative approach to a sustainable energy policy", no. 1024, pp. 75–75, 2019. [2] a. z. k. aziz, s., burki, s. j., ghaus-pasha, a., hamid, s., hasan, p., hussain, a., & sherdil, "third annual report—state of the economy: pulling back from the abyss", 2010. [3] bp, "statistical review of world energy globally consistent data on world energy markets and authoritative publications in the field of energy the statistical review world of world energy and data on world energy markets from is the review has been providing", p. 66, 2020. [4] iea, "international energy agency (iea)", 2014. [5] h. qudrat-ullah, "independent power (or pollution) producers? electricity reforms andipps in pakistan", energy, vol. 83, pp. 240–251, 2015. [6] e. y. book, "primary energy mix", encycl. corp. soc. responsib., pp. 1892–1892, 2013. [7] hdip, "hydrocarbon development institute of pakistan: islamabad". 2017. [8] m. m. rafique, s. rehman, "national energy scenario of pakistan – current status, future alternatives, and institutional infrastructure: an overview", renew. sustain. energy rev., vol. 69, no. november 2016, pp. 156–167, 2017. [9] t. h. l. p. nguyen, "is energy security a driver for economic growth? evidence from a global sample", energy policy, vol. 129, no. february, pp. 436–451, 2019. [10] t. aized, m. shahid, a. a. bhatti, m. saleem g. anandarajah, "energy security and renewable energy policy analysis of pakistan", renew. sustain. energy rev., vol. 84, no. september 2016, pp. 155–169, 2018. [11] government of pakistan, "policy framework and package of incentives for private sector power generation projects in pakistan". pp. 1– 22, 1994. [12] h. ishaque, "is it wise to compromise renewable energy future for the sake of expediency? an analysis of pakistan’s longterm electricity generation pathways", energy strateg. rev., vol. 17, pp. 6–18, 2017. [13] a. malik, "how pakistan is coping with the challenge of high oil prices", pak. dev. rev., vol. 46, no. 4, 2007. [14] a. h. abbasi, f. mahmood, m. kamal, a. baig, "pakistan energy vision 2035", sustain. dev. policy inst., pp. 7–8, 2014. [15] unep, "united nations environment program", unep, 2020. [online]. available at: https://www.thebalancesmb.com/what-issustainability-3157876. [16] z. yu zhao, h. yan, "assessment of the biomass power generation industry in china", renew. energy, vol. 37, no. 1, pp. 53–60, 2012. [17] y. lei, "swot analysis for the development of photovoltaic solar power in africa in comparison with china", environ. impact assess. rev., vol. 77, no. april, pp. 122–127, 2019. [18] x. shi, "the future of asean energy mix : a swot analysis", renew. sustain. energy rev., vol. 53, pp. 672–680, 2016. [19] b. cayir ervural, s. zaim, o. f. demirel, z. aydin, d. delen, "an anp and fuzzy topsis-based swot analysis for turkey’s energy planning", renew. sustain. energy rev., vol. 82, no. april 2016, pp. 1538–1550, 2018. [20] y. khalil, "strengths , weaknesses , opportunities , and threats ( swot ) analysis of fission nuclear power for electricity generation」, no. april 2003, 2017. [21] c. fertel, o. bahn, k. vaillancourt, j. p. waaub, "canadian energy and climate policies: a swot analysis in search of federal/provincial coherence", energy policy, vol. 63, pp. 1139–1150, 2013. [22] f. a. ishola, o. o. olatunji, o. o. ayo, s. a. akinlabi, p. a. adedeji, a. o. inegbenebor, "sustainable nuclear energy exploration in nigeria a swot analysis, procedia manuf., vol. 35, pp. 1165–1171, 2019. [23] y. wang, l. xu, y. a. solangi, "strategic renewable energy resources selection for pakistan: based on swot-fuzzy ahp approach", sustain. cities soc., vol. 52, no. september 2019, 2020. [24] m. kamran, m. r. fazal, m. mudassar, "towards empowerment of the renewable energy sector in pakistan for sustainable sikander ali abbasi (et al.), evaluation of oil-based power generation of pakistan. swot-delphi approach (pp. 45 58) sukkur iba journal of emerging technologies sjet | vol. 4 no. 1 january – june 2021 58 energy evolution: swot analysis", renew. energy, vol. 146, pp. 543–558, 2020. [25] s. r. shakeel, j. takala, w. shakeel, "renewable energy sources in power generation in pakistan", renew. sustain. energy rev., vol. 64, no. december 2018, pp. 421–434, 2016. [26] r. r. r. m. rooshdi, m. z. a. majid, s. r. sahamirとn. a. a. ismail, "relative importance index of sustainable design and construction activities criteria for green highway", chem. eng. trans., vol. 63, no. 2007, pp. 151–156, 2018. [27] us epa, "global greenhouse gas emissions data", us epa, 2010. [online]. available at: https://www.epa.gov/ghgemissions/globalgreenhouse-gas-emissions-data. [28] world bank, "international energy agency (iea)", iea, 2017. [online]. available at: http://www.iea.org. format template vol. 2, no. 1 | january june 2019 sjet | p-issn: 2616-7069 | e-issn: 2617-3115 | vol. 2 | no. 1 | © 2019 sukkur iba 20 reactive power compensation using matrix converter: indirect space vector pulse width modulation technique muhammad ishaq1, muhammad hammad afzal1, mukhtar ali1, muhammad waqar2 abstract: in this paper, application of matrix converter for the compensation of reactive power is studied. matrix converter is direct ac-ac converter composed of solid-state bi-directional switches. space-vector modulation technique is used to control the matrix converter. simulation are done in matlab/simulink and filters are used to smooth out the output waveforms. switching frequency optimization is done and its effect on thd and input/output currents/voltages is observed. keywords: matrix converter control, space vector pwm, reactive power compensation 1. introduction reactive power (q) limits the capacity of a transmission line because it is the unused power. presence of large amount of q, consequently, limits the amount of active useful power (p) which can be transmitted across the transmission line. it is therefore, extremely important in power systems to develop a system which can control and reduce reactive power. higher q also affects the voltage across the transmission line so this compensation system would also allow to control the voltage of transmission line. there are many traditional methods to control and compensate reactive power such as facts controllers and capacitor banks. capacitor banks are bulky, heavy and expensive and they also require regular maintenance. facts, on the other hand, are 1 department of electrical engineering, national university of computer and emerging sciences, h11/4, islamabad, pakistan 2 smme, national university of science and technology, h-12, islamabad, pakistan corresponding author: muhammadishaq1359@gmail.com relatively better and more controllable but they still require the use of capacitors, such as in svc large capacitor is used to handle high voltage [1]. whereas, in statcom smaller electrolytic capacitor is used on dc side. fig 1:matrix converter schematic muhammad ishaq (et al.), reactive power compensation using matrix converter: indirect space vector pulse width modulation technique (pp. 20 26) sukkur iba journal of emerging technologies sjet | volume 2 no. 1 january – june 2019 © sukkur iba university 21 fig 2:an indirect matrix converter reactive power can also be controlled by matrix converter (mc). mc was first proposed by alesina and venturini in 1989 [2]. they extensively studied mc and researched on low frequency behaviors of voltages and currents at the output of the system. earliest difficulties in the research of mc were the commutation of the bidirectional switches [8]. work around for commutation problems was found by [7] by using intelligent commutations techniques. mc is direct ac-ac converter as shown in figure 1. it consists of 9 bi-directional switches and it eliminates the need of intermediate dc-link required in traditional back to back converters. features of mc includes sinusoidal waveforms at output, control of output amplitude and frequency, compact design due to use of solid-state semiconductor components, regeneration and unity power factor at input [3]. 2. matrix converter matrix converter is an ac-ac converter which is arranged in 3x3 array of 9 bidirectional switches. there are two main types of mc topologies: direct and indirect as shown in figure 2. indirect mc consists of two stages, first is rectification stage and second is inversion stage. an imaginary dc-link is assumed between these two stages for the purpose of modulation of mc [4]. relationship between input and output voltage and current is represented by (1) and (2). fig 3: 3x3 direct matrix converter. table i: 27 switching states of direct matrix converter. muhammad ishaq (et al.), reactive power compensation using matrix converter: indirect space vector pulse width modulation technique (pp. 20 26) sukkur iba journal of emerging technologies sjet | volume 2 no. 1 january – june 2019 © sukkur iba university 22 (1) relates input voltage with output current whereas (2) relates output current with input current. direct mc has 9 switches. therefore, total 29=512 switching combinations are possible. but these combinations are further constrained by following rules [5]: • two input terminals cannot be short circuited. • an output terminal cannot be left open. these rules can be expressed by following equations [4]: saa+sab+sac=1 () sba+sbb+sbc=1 () sca+scb+scc=1 () 27 switching combinations are categorized into three parts [5]: • 3 zero vectors (all output lines connected to a same input terminal). • 6 rotating vectors (every output line connected to a different input terminal). • 18 active vectors (two output lines connected to one input terminal, the third line to another terminal one input terminal is not connected). 3. control scheme for matrix converter in this research direct topology of matrix converter will be used for simulation but for modulation, indirect matrix converter will be assumed in which first stage will be modulated as current source rectifier (csr) and second fig 6: csr stage current space-vectors. fig 4: vsi stage voltage spacevectors in complex plane. fig 5: transformation of 12 gate signals into 9. muhammad ishaq (et al.), reactive power compensation using matrix converter: indirect space vector pulse width modulation technique (pp. 20 26) sukkur iba journal of emerging technologies sjet | volume 2 no. 1 january – june 2019 © sukkur iba university 23 stage will be modulated as voltage source inverter (vsi) [6]. voltage and current space vectors are shown in figure 4 and 5 respectively. control scheme outputs 12 gating signals, 6 signals for csr namely sap, san, sbp, sbn, scp, scn and 6 signals for vsi namely sap, san, sbp, sbn, scp, scn. conversion from 12 gating signals to 9 signals such as saa, sab, sac, sba, sbb, sbc, sca, scb, scc, is done by the process demonstrated in figure 6. a reference input is given to each control stage such as current reference for csr and voltage reference for vsi. there are 23 = 8 switching states of vsi because two switches in one leg cannot be closed simultaneously. there are 6 active vectors as shown in figure 5 and other two are called zero vector where fig 7: switching states of vsi stage. fig 8: switching states of csr stage. muhammad ishaq (et al.), reactive power compensation using matrix converter: indirect space vector pulse width modulation technique (pp. 20 26) sukkur iba journal of emerging technologies sjet | volume 2 no. 1 january – june 2019 © sukkur iba university 24 either all positive terminal switches or all negative terminal switches are closed. expression (6) and (7) represent voltage and current space vectors [7]. where q is modulation index and θsv=ωt-φi, and φi is input displacement angle which is required to be controlled to reduce reactive power. the expression for virtual dc link is given in (8). edc is dc link voltage and it is also the length of all active vectors. reference vectors rotate in fig 4 and 5 with angular velocity of ω. reference vectors are formed by 2 closely located active vectors and a zero vector [6]. where ta1 is time duration of application of first active vector and similarly ta2 for second active vector and tz for zero vector. ts is sampling time. 4. simulation results two systems as shown in fig 9 are simulated, one with matrix converter and one without it. from these simulations, it can be observed that using matrix converter to control the input displacement angle results in reduced reactive power in the system. figure 10 shows voltage and current waveforms of system where reactive power control has not been implemented, here the displaced angle is about 51 degrees. figure 12 shows output voltage and current at two different frequencies i.e 5000 hz and 10000hz. although increasing switching frequency improves the output current waveform, it increases total harmonic distortion (thd) in output voltage. so, a tradeoff is found between switching frequency and acceptable amount of thd in figure 11. figure 13 shows input voltage and current waveform while using matrix converter to control displacement angle. it can be observed from the figure that current closely follows voltage resulting in reduced reactive power. figure 14 shows improvement in smoothness of input current waveform when an input filter is used. fig 10: displacement between voltage and current without matrix converter. fig 9: simulation diagram. 𝑇𝑎1 = 𝑇𝑠 3 2 𝑞𝑉𝑖 sin 𝜋 3 −𝜃𝑠𝑣 𝑒𝑑𝑐 sin 𝜋 3 𝑇𝑎2 = 𝑇𝑠 3 2 𝑞𝑉𝑖 sin 𝜃𝑠𝑣 𝑒𝑑𝑐 sin 𝜋 3 𝑇𝑧 = 𝑇𝑠 − 𝑇𝑎1 − 𝑇𝑎2 muhammad ishaq (et al.), reactive power compensation using matrix converter: indirect space vector pulse width modulation technique (pp. 20 26) sukkur iba journal of emerging technologies sjet | volume 2 no. 1 january – june 2019 © sukkur iba university 25 different switching frequencies are tested to find a range of different switching to reduce power losses as well as total harmonic distortion of signals. it can be observed in figure 11 that range of switching frequency between 5000hz to 7000hz is sufficient because increasing frequency beyond this point don’t have any significant effect on thd. 5. conclusion in conclusion, space vector pulse width modulation technique (svpwm) is indirectly applied to a 3x3 direct matrix converter (dmc). simulation performed in simulink are presented. this system of matrix converter has capability of performing in wide variety of situations and yield consistent results. reactive power compensation is achieved by using inductive load. any type of load can be used such as inductive or capacitive. output waveforms are affected by distortion due to switching of bidirectional switches, this total harmonic distortion is reduced to an optimum level by extensively studying wide range of switching frequencies. references [1] k. padiyar, facts controllers in power transmission and distribution, new age international publishers, 2007. [2] k. hulusi and a. ramazan, "control of venturini method based matrix converter in input voltage variations," international multiconference of engineers and computer scientists, 18-20 03 2009. fig 12: output voltage and current after using filter. fig 13: input voltage and current waveforms of mc. fig 14: input current after using filter. muhammad ishaq (et al.), reactive power compensation using matrix converter: indirect space vector pulse width modulation technique (pp. 20 26) sukkur iba journal of emerging technologies sjet | volume 2 no. 1 january – june 2019 © sukkur iba university 26 [3] s. pawel, three-phase ac-ac power converters based on matrix converter topology, springer, 2013. [4] h. nathelie and m. marta, "reactive power compensation using an indirectly space vector-modulated matrix converter," ieee international symposium on industrial electronics (isie), pp. 2455-2460, 08 2010. [5] r. jose, r. marco, k. johan and w. patrick, "a review of control and modulation methods for matrix converters," ieee transactions on industrial electronics, pp. 58-70, 01 2012. [6] b. kuldeep and b. subrat, "a novel control strategy of indirect matrix converter using space vector modulation," international journal of power electronics and drive system (ijpeds), vol. 03, no. 07, pp. 926-935, 2016. [7] o. khaled, d. mohamed and j. mohamed, "a svm control strategy for a direct matrix converter," ieee transactions on power electronics , pp. 1-10, 2013. [8] l. zhang, c. watthanasarn, and w. shepherd, “control of ac–ac matrix converters for unbalanced and/or distorted supply voltage,” in proc. 32nd annu. ieee power electron. spec. conf., 2001, vol. 2, pp. 1108–1113. format template vol. 4, no. 1 | january – june 2021 sjet | p-issn: 2616-7069 |e-issn: 2617-3115 | vol. 4 no. 1 january – june 2021 22 urban road traffic sign detection & recognition with time space relationship model bhutto jaseem ahmed1, qin bo1, qu jabo1, zhai xiaowei1, abdullah maitlo2 abstract: detection and recognition of urban road traffic signs is an important part of the modern intelligent transportation system (its). it is a driver support function which can be used to notify and warn the driver for any possible incidence on the current stretch of road. this paper presents a robust and novel time space relationship model for high positive urban road traffic sign detection and recognition for a running vehicle. there are three main contributions of the proposed framework. firstly, it applies fast color-segment algorithm based on color information to extract candidate areas of traffic signs and reduce the computation load. secondly, it verifies the traffic sign candidate areas to decrease false positives and raise the accuracy by analysing the variation in preceding video-images sequence while implementing the proposed time space relationship model. lastly, the classification is done with support vector machine with dataset from real-time detection of tsrm. experimental results indicate that the accuracy, efficiency, and the robustness of the framework are satisfied on urban road and detect road traffic sign in real time. keywords: traffic sign detection & recognition; time space relationship model; fast color segmentation and compression; intelligent transportation system 1. introduction as an intelligent transportation system (its) road traffic sign detection and its recognition are playing an increasingly instrumental role for providing road safety to the drivers. autonomous detection and recognition of traffic sign plays an extremely vital role in advance driver assistance system (adas) of possible danger such as pedestrian crossing or speed limits. on-road traffic sign/symbols exhibits several distinguish features i.e., shape and color that can be used to detect and recognize them. with their composition of specific shape, color and having the text or symbol imprinted over the circular, triangular or 1 department of computer science & technology, ocean university of china, qingdao, china 2 computer science department, shah abdul latif university khairpur, pakistan. corresponding author: jaseem.bhutto@gmail.com rectangle board with background colors like red, yellow, and blue; it has become important to detect and recognize them in an effective way. but as the traffic signs have their orientation upright and facing the camera, hence rotational and geometric distortion is limited. the availability of knowledge about traffic symbols (shape and color) as a source be used to categorize into specific groups after carefully examining and analyzing various factors that can hinder in effective detection and recognition of the traffic signs. these factors may include perspective variations, different levels of illumination, twilight, fog, shadowing, obstacles in scene, motion blur, weather and affects etc. which can lead to limited scope of detection and recognition. bhutto jaseem ahmed (et al.), urban road traffic sign detection and recognition with time space relationship model (pp. 22 33) sukkur iba journal of emerging technologies sjet | vol. 4 no. 1 january – june 2021 23 to deal all this, accuracy and efficiency of the detection system is must, as a single misclassified or undetected sign can be cause of the unfavorable impact for the driver. there had been an extensive research in the said field, but a real-time system had not been developed yet, which could hinder the urban road accidents. the traffic sign detection systems, however, can be classified into either or both scenarios; shape based, and color based. different types of color spaces have been used which includes his-hsv [1] [2], yuv [3] or gaussian color model [4] to define traffic sign region as visual features. similarly, the shape features, such as hough transform [5], local contour pattern [6] or local binary pattern [7] have also been used. additionally, many latest developments in computer vision [8] [9] have focus on the images, based on three dimensional (3d) reconstructions. semantic texton forests and image-based 3d points clouds have been used for categorization, segmentation, and recognition of highway assets [10]. support vector machine (svm) and semantic texton forests were proposed by [10] [11] and are being used to recognize the traffic signs. the vertical traffic sign classification and recognition is focused by [12] (retro-reflective) for their various functionalities (danger, give way, indication etc.). the recognition was also achieved by adapting gaussian-bernoulli deep boltzmann (gbdb) machine model based on the hierarchal classifier [13]. global strategy for the detection can be used which is based on filtering the noise point by distance setting & threshold elevation and the segmentation region of traffic sign can then be obtained. this paper introduces a video-based traffic sign detection and recognition system / framework, which could be embedded into mobile intelligent system for intelligent vehicles. the system is based on continuous video of the on-road vehicle movements. this is a seed to mobile intelligent system, which can realize real-time traffic sign detection and recognition accurately and efficiently in the complex urban road environment. the rest of this paper is organized as follows: section 2 briefly shows the in-depth step by step process of proposed system. in section 3, fast segmentation and compression algorithm and time space relationship model has been discussed in detail. in section 4, we analyze the experimental data. in section 5, we discuss the process of dataset training, classification, recognition, and comparison of results using tsmr and other literatures. finally, we conclude the paper in section 6 and forthcoming recommendations are given in section 7. 2. proposed architecture fig. 2 is the proposed architecture which gets the video sequence and set region of interest first and then fast segmentation and compression algorithm is applied, which reduces the computation load and increases the efficiency. later, time space relationship model (tsmr) is used on video sequence with hog feature to track and detect the object in sequence of video. finally, svm is used to classify and recognize the traffic sign. fig. 1. different varied types of traffic signs (source: european traffic signs collection. danger, mandatory & signs of obligations) bhutto jaseem ahmed (et al.), urban road traffic sign detection and recognition with time space relationship model (pp. 22 33) sukkur iba journal of emerging technologies sjet | vol. 4 no. 1 january – june 2021 24 3. algorithm and model design the proposed algorithm is used to segment the image quickly by using the compression algorithm to get the binary image of the traffic sign candidate region. the fast color segmentation and compression algorithm stores the pixels that meet the segmentation threshold into compressed binary image according to the block model. the color segmentation threshold parameters are optimized for the actual urban road scenes, the output images are compressed by the “block” strategy and connected regions are merged then. 3.1. fast color segmentation and compression algorithm • step 1: convert rgb image into hsv image 𝐼(𝑥, 𝑦); • step 2: set all the pixels (𝑥𝑖 , 𝑦𝑖 ) in image 𝐼 to white if they satisfy the segmentation threshold of a color, that is, ∀(𝑥𝑖 , 𝑦𝑖 ) ∈ 𝐼(𝑥, 𝑦). 𝐶𝑜𝑙𝑜𝑟 (𝑥𝑖 , 𝑦𝑖 ) = { 255, 𝑖𝑓 𝐻((𝑥𝑖 , 𝑦𝑖 ), 𝑆(𝑥𝑖 , 𝑦𝑖 ), 𝑉(𝑥𝑖 , 𝑦𝑖 ) 𝑎𝑙𝑙 𝑎𝑟𝑒 𝑠𝑎𝑡𝑖𝑠𝑓𝑖𝑒𝑑. 0, 𝑂𝑡ℎ𝑒𝑟𝑤𝑖𝑠𝑒 (1) where color represents a binary image divided for a certain color segmentation step 3: the image 𝐼 is divided into 𝑀 × 𝑁 of size 𝑚 × 𝑚 sub-image blocks of 𝐴𝑖,𝑗 (𝑖 = 1, 2, 3 . . , 𝑀; 𝑗 = 1,2,3 … , 𝑁). the correspondence between image 𝐶𝑜𝑙𝑜𝑟 and the segmentation result image 𝐵𝑖𝑛𝑎𝑟𝑦 satisfies: 𝐵𝑖𝑛𝑎𝑟𝑦(𝑖, 𝑗) = { 255, 𝑖𝑓 𝐶𝑜𝑢𝑛𝑡𝑖,𝑗 ≥ 𝑡ℎ𝐶 0, 𝑖𝑓 𝑜𝑡ℎ𝑒𝑟𝑤𝑖𝑠𝑒 (2) the formula 2 𝐶𝑜𝑢𝑛𝑡𝑖,𝑗 represents number of white pixels in sub-image block 𝐴𝑖,𝑗 , the 𝑡ℎ𝐶 is the threshold. after this step, the original image 𝐼 is segmented and compressed by an image size of 𝑚 × 𝑚 𝐵𝑖𝑛𝑎𝑟𝑦 image. fig. 3 shows the mapping relationship between color and binary. • step 4: the adjacent areas are merged, and the adjacent connected areas in the image 𝐵𝑖𝑛𝑎𝑟𝑦 are combined into one region to prevent the traffic area sign from being missing due to change of illumination conditions, and the integrity of the traffic mark area is ensured to obtain the image segment. • step 5: fig. 4 shows the output of traffic sign segmentation image. fig. 2. detection & recognition architecture t i m e l i n e frame(t) frame(t+1) frame(t+n) pre-image proessing fast color segmentation & compression algorithm time space relationship model traffic sign detection ... continuous video frame sequence extract hog features continuous processing classification training set video sequence set roi "block" strategy geometric features multi-frame tacking output the result a) region of interest (b) hsv images m m color image width=m×n; height=m×m binary image width=n; height=m fig. 3. color and binary application mapping bhutto jaseem ahmed (et al.), urban road traffic sign detection and recognition with time space relationship model (pp. 22 33) sukkur iba journal of emerging technologies sjet | vol. 4 no. 1 january – june 2021 25 fig. 4. segmentation & compression algorithm 3.1.1. block size selection strategy in step 3, the image 𝐼 is divided into 𝑀 × 𝑁 sub-image blocks of size 𝑚 × 𝑚. the selection of 𝑚 and the selection threshold of 𝑡ℎ𝐶 will affect the segmentation result image 𝐵𝑖𝑛𝑎𝑟𝑦. 3.1.1.1. selection of value of block size m image. fig. 5 shows the segmentation results of original image 5 (a) at m = 1, 2, 4, 8 and 16, respectively. comparing fig. 5. if m≤8 the segmentation shape, result basically maintains the original shape. if the value of m is too large, the area of the segmented image is too large or too small, which will affect the detection result. if the value of m is too small, the effect of reducing the amount of data by compressing the image will not be achieved. if value of m is fixed, the size of the original image will also have some influence on the image. fig. 6 shows the effect of 𝑚=8 as an example on the segmentation of different size images. if the value of m is too large, it will contain more noise zones and the error will fluctuate greatly. if the value of m is too small, there is possibility of missing traffic sign. if the m value is fixed, the image size will have an impact on the segmentation and improves efficiency. the paper will take m=4 to improve accuracy and efficiency. 3.1.1.2. selection of screening threshold thc. as shown in fig. 7 the size of 𝑡ℎ𝐶 in (e) and (f) is too large, which causes the fracture of the traffic sign area and affects the detection of traffic signs. the general segmentation to ensure the normal traffic area, select the 𝑡ℎ𝐶 = 1 8⁄ or 𝑡ℎ𝐶 = 1 4⁄ . as shown in fig. 7. (c) red segmentation. (d) region consolidation (a) original (b) undivided (c) 𝑚 = 2 (d) 𝑚 = 4 (e) 𝑚 = 8 (f) 𝑚 = 16 fig. 5. 𝑚 value of traffic sign segmentation (a) size 200 x 192 b) size 106 x 104 c) size 54 x 61 fig. 6. segmentation result of size 𝑚 = 8 (a) original image (b)𝑡ℎ𝐶 = 0 (c) 𝑡ℎ𝐶 = 1 8⁄ (d)𝑡ℎ𝐶 = 1 4⁄ (e)𝑡ℎ𝐶 = 1 4⁄ (f) 𝑡ℎ𝐶 = 2 3⁄ fig. 7. different segmentation threshold 𝑡ℎ𝐶 with m = 8 bhutto jaseem ahmed (et al.), urban road traffic sign detection and recognition with time space relationship model (pp. 22 33) sukkur iba journal of emerging technologies sjet | vol. 4 no. 1 january – june 2021 26 3.1.2. adjacent region merging as shown in fig. 4 (d), when traffic signs are segmented, the traffic sign area will be broken into several adjacent small, connected regions due to the change of illumination condition, the size of block m and the thc of screening threshold. at this point, adjacent areas need to be merged. the specific implementation is as shown in fig. 8. • step 1: in the image binary, the size is set as m × m pixels (m generally takes 2 or 3, m = 3 as an example in this case). 𝑁𝑢𝑚(𝑊ℎ𝑖𝑡𝑒)represents the number of white pixels in the set, and 𝑡ℎ𝑅 is the merge threshold parameter. if 𝑁𝑢𝑚(𝑊ℎ𝑖𝑡𝑒)and 𝑡ℎ𝑅 satisfy the relation of formula (3) 𝑁𝑢𝑚(𝑊ℎ𝑖𝑡𝑒) ≥ 𝑡ℎ𝑅 (3) the white pixel points of the set belong to the same connected area, and the black pixel points in the set are modified to white. if the formula (3) is not satisfied, the white pixel point in the region is identified as an isolated point, and it is set to black, and fig. 8 represents the process. • step 2: as shown in fig. 9, traverse the binary image until the merge is complete. 3.2. time space relationship model there are limitations of traffic sign detection (tsd) based on a single frame [14]. due to camera’s point of view, different angles and other factors, the specific location of the traffic sign (ts) in the image plane is uncertain [15]. and the tilted, distorted, broken ts leads to irregular connected areas. thus, tsd based on a single frame has high false positive and low robustness. therefore, based on the continuous change relationship between the time and space position of traffic sign in the continuous sequence of traffic scenes, a time space relationship model is proposed to detect and verify the traffic sign candidate regions furthermore. fig. 10 demonstrates the on-road side view scene. fig. 11 exemplifies the structural relationship among traffic sign, image planes and camera at a certain time. as seen in fig. 11, 𝒇 is focal length of camera. d is the vertical distance between image plane and traffic sign. l is the size of the traffic sign on the image plane. s is the actual size of traffic sign. note that l and s stand for the perimeter or area of traffic sign. (a)satisfies formula (3) (b) doesn’t satisfy formula (3) fig. 8. step 1 processing for region merging. se t 1 se t 2 fig. 9. step-2 traversal process of region merging. ground camera optical axis camera image plane traffic signs perspective fig. 10. side view of the scene bhutto jaseem ahmed (et al.), urban road traffic sign detection and recognition with time space relationship model (pp. 22 33) sukkur iba journal of emerging technologies sjet | vol. 4 no. 1 january – june 2021 27 according to similar triangle principle, drawn formula (4), 𝒇 𝒇+𝒅 = 𝑳 𝑺 (4) as the value of 𝒇 is much smaller than the value of d, the formula (4) can be simplified into formula (5): 𝒇 𝒅 = 𝑳 𝑺 (5) thus, size of traffic sign on image plane l is: 𝑳 = 𝒇 . 𝑺 𝒅 (6) as the distance d between traffic sign and the camera decreases, the size 𝑳 of the traffic sign in the image increases accordingly. at the same time, traffic signs in the image position begin to move up. in a certain period of time in the ∆𝑇(𝑡1, 𝑡2, … , 𝑡𝑛), the size and position of the traffic sign area 𝑳 in the continuous image sequence of the traffic scene shows a continuous change. there will be no sudden appearance or disappearance of traffic signs, but a continuous process of change. set 𝐿𝑚𝑎𝑥 , 𝐿𝑚𝑖𝑛 for traffic signs to meet the minimum and maximum size of the detection. every frame of image corresponds to a connected region 𝑅′𝑖 (𝑖 = 1,2, … , 𝑛) in the period of ∆𝑇(𝑡1, 𝑡2, … , 𝑡𝑛), and any traffic sign detection candidate area 𝑙1 ∈ 𝑅′1, if the area appears in consecutive multi-frames, it is determined that the area is a traffic sign area; otherwise, it is determined as a noise area. specific findings based on the following: according to the continuous change of traffic signs in the sequence of traffic scene images, the expression of a candidate region in each frame which is set in ∆𝑇(𝑡1, 𝑡2, … , 𝑡𝑛) is 𝐿(𝑙1, 𝑙2, … , 𝑙𝑛). the sizes of 𝑙𝑖 (𝑖 = 1,2, … , 𝑛) are all the same or nonexistent (undetected). suppose l is in the time period 𝑡𝑖 , … , 𝑡𝑗 (1 ≤ 𝑖 < 𝑗 ≤ 𝑛, 𝑀 = |𝑗 − 𝑖 + 1|). if the connected region set 𝑅′𝑘 𝑙𝑘 (𝑖 ≤ 𝑘 ≤ 𝑗), marking its state as 1, otherwise 0, then the state sequence corresponding to 𝑙𝑘 in time 𝑡𝑖 , … , 𝑡𝑗 is 𝐹[𝑓𝑖, 𝑓𝑖+1, … , 𝑓𝑗 ], where 𝑓𝑘 = { 1, 𝑖𝑓 𝑙𝑘 𝑒𝑥𝑖𝑠𝑡𝑠 0, 𝑜𝑡ℎ𝑒𝑟𝑤𝑖𝑠𝑒 (𝑖 ≤ 𝑘 ≤ 𝑗) (7) in the state sequence 𝐹, the number of 𝑓𝑘 = 1 and 𝑁𝑓=1 = ∑ 𝑓𝑘 𝑘=𝑗 𝑘=𝑖 and the threshold 𝑖𝑠 𝑅𝑓 , then 1. if 𝑁𝑓=1 𝑀 < 𝑅𝑓 , it is determined that l is the background noise in the traffic sign detection candidate region. 2. if 𝑁𝑓=1 𝑀 ≥ 𝑅𝑓 , it is determined that the traffic sign detection candidate region is l as the traffic sign area. if l is the traffic sign area, the traffic sign information area of the missing or lost frame can be backtracked. the missing frame state value (𝑓 = 0) in 𝐹[𝑓𝑖 , 𝑓𝑖+1, … , 𝑓𝑗 ] is modified to (𝑓 = 1), and its location and size are determined same time. f d l s cameracamera traffic signtraffic sign image plane image plane fig. 11. spatial constraints among traffic sign, image planes and the camera time x y t1 ti tj tn ... ... frame1 framei framej framen ...... ...... fig. 12. framework of traffic sign detection and recognition based on tsrm. bhutto jaseem ahmed (et al.), urban road traffic sign detection and recognition with time space relationship model (pp. 22 33) sukkur iba journal of emerging technologies sjet | vol. 4 no. 1 january – june 2021 28 similarly, the traffic sign candidate area 𝐿 can be iteratively tracked in the time period after the time point 𝑡𝑗 according to the continuous change in relationship (i.e., position offset and size change) of the traffic sign 𝑡𝑖, … , 𝑡𝑗 (1 ≤ 𝑖 < 𝑗 ≤ 𝑛)), the process is a recursive process. the function tracking (𝑡𝑖, 𝑀) is used to trace the location and size of 𝐿 in a continuous m frame after the start of the 𝑡𝑖 moment. the recursion terminates the following three: 1. l position beyond the border. 2. l size is greater than the maximum size of traffic signs 𝐿𝑚𝑎𝑥 ; 3. 𝑀 ≤ 1; recursive body: tracking (𝑡𝑖, 𝑀) tracks 𝐿 while checking whether it is a traffic sign. if the frame tracking results in the m frame are verified correctly, 𝑖 = 𝑖 + 𝑀, 𝑀 = m/2 will be followed; otherwise, the tracking will be stopped directly. recursive function body, tracking (𝑡𝑠𝑡𝑎𝑟𝑡 , 𝑀) tracks the traffic sign estimated region and verify whether it is a traffic sign or not. if the verification results are true in more than half of m frames, then 𝑡𝑠𝑡𝑎𝑟𝑡 = 𝑡𝑠𝑡𝑎𝑟𝑡 + m, m = m/2, and call tracking (𝑡𝑠𝑡𝑎𝑟𝑡 , 𝑀). otherwise, break iterative loop. 4. experimental data analysis the analysis of the data using the above algorithm and developed model for the “traffic sign detection and recognition has many dimensions. we worked on limiting the data sets in addition to finding a reliable and efficient detection and recognition system. the experimental data is achieved by the driving recorder in different time periods and in different light conditions. the resolution of the video image is 1920 × 1080 and the frame rate is 30fps. video contains morning, noon, afternoon, and other time periods including cloudy, sunny, rainy, foggy, and other weather conditions. this paper mainly evaluates the algorithm in terms of accuracy, robustness, and efficiency. the specific parameters of the running environment are shown in table 1. table 1. operating environment specific parameters operating environment 64 bits windows ultimate cpu intel(r) core (tm) i5-3450 ram 8gb runtime environment visual studio 2013 opencv edition opencv3.0 programming lang. c++ 4.1. robustness testing according to the different partitioned block size in the image segmentation compression algorithm, this paper tests the uninterrupted operation of video for more than 10 hours. the experiment results show that different sizes of partitioned blocks are set as 2, 4, 6, 8 and 16. there is no memory overflow, limited access or program interruption during the processing. in this paper, urban road traffic sign detection algorithm based on time space relationship model is robust and the program has high stability. 4.2. accuracy testing table 2. experiment results at different time table 2. shows accuracy results of traffic sign detection at different time slots in a day in three different videos. whereas fig. 13 shows that this algorithm has better detection effect for complex road background, varying videos timing number accuracy 01 morning 309 90.94% 02 noon 285 90.88% 03 afternoon 257 91.44% bhutto jaseem ahmed (et al.), urban road traffic sign detection and recognition with time space relationship model (pp. 22 33) sukkur iba journal of emerging technologies sjet | vol. 4 no. 1 january – june 2021 29 weather conditions when processing video data. fig. 14 shows the comparison in between a video, before and after applying the time space relationship model, where tsrm eliminates the false positive candidate regions. through the processing of 3 hours of video, the test results before and after applying time space relationship model are shown in table 3. from the test results, it can be seen that the accuracy of traffic sign detection is increased with tsrm nearly by 8% and the missed detection rate is reduced by nearly 7%. table 3. result comparison with tsrm experimental results the number of signs before tsrm after tsrm actual signs 309 309 tested signs 345 321 correctly detected 257 281 missed detection 52 28 missing rate 16.83% 9.06% accuracy 83.17% 90.94% whereas table 4 compares this algorithm with other literature algorithms. this paper not only outperforms literature [16] and literature [17] in accuracy, but also takes much less time to process high resolution images than other literature. therefore, this algorithm meets the real-time detection requirements in mobile system. table 4. comparison between proposed algorithm and other literature algorithms parameter literature this paper [16] [17] accuracy rate 90.94% 86.8% 90.86% image size 1920 × 1080 640 × 480 1360 × 800 processing time 25ms 200ms 780ms (a) normal background (b) the dark background (c) complex road background fig. 13. test results under various conditions (a) before application (b) after application fig. 14. result before and after tsrm. bhutto jaseem ahmed (et al.), urban road traffic sign detection and recognition with time space relationship model (pp. 22 33) sukkur iba journal of emerging technologies sjet | vol. 4 no. 1 january – june 2021 30 4.3. efficiency the frame rate of the experimental video is 30fps, and the resolution of each image is 1920*1080. the average detection time of each image is about 25ms, that is, 40 frames per second can be processed to meet the realtime processing requirements. therefore, the system is considerably efficient. 5. traffic sign recognition using svm the traffic sign detection and recognition were done by real-time capturing of the data and then analysing the obtained frames. the recognition analysis was done using the support vector machine (svm). table 5. traffic sign recognition sample library no. traffic sign icon sample numbers 01 no stopping 252 02 speed limit 40 228 03 no horn 204 04 watch for pedestrians 232 05 attention traffic lights 180 06 turn right sign 196 07 others / 960 5.1. traffic sign classification according to the color and shape characteristics of traffic signs the candidate areas are labelled as prohibited signs (red), warning signs (yellow) and indicating signs (blue) in the color segmentation stage. further classification is made according to the shape, and fig. 15 is the process of classification and recognition of traffic signs: in the red sign, the hough circle detection is carried out in the candidate region image. if there is a circle, it is divided into the subclass 1; otherwise, it is judged as noise. in the yellow warning sign, the canny operator edge detection is carried out on the candidate region image, and the positive triangle detection method is adopted. if the region is triangle, it is divided into the subclass 2; otherwise, judged as noise & discarded. in the blue indicator, the image of the candidate region is detected by hough circle. if there is a circle, it is divided into subclass 3; otherwise, it is divided into the subclass 4. 5.2. dataset training & recognition this paper uses svm trainer in opencv computer vision library to implement the classification of traffic signs. the recognition framework process is as follows: video image frame color detection red area yellow area blue area circular triangle circular yes yes yes subclass 1 subclass 2 subclass 3 no noise subclass 4 no noise rectangle yes no noise no fig. 15. traffic sign classification process test set training set hog features extract hog features extract svm class ifier training classification recognition output recognition result fig. 16. svm dataset training & recognition process bhutto jaseem ahmed (et al.), urban road traffic sign detection and recognition with time space relationship model (pp. 22 33) sukkur iba journal of emerging technologies sjet | vol. 4 no. 1 january – june 2021 31 when the algorithm is implemented, the hog feature of the traffic sign in the sample library is extracted first, and then the svm classifier is used to train the sample to obtain the traffic sign classifier. when the traffic sign in the traffic video is detected, it is sent to the svm classification according to the classification results output. fig. 17 shows the traffic sign recognition result. here in fig. 17, we can see that speed sign is perfectly detected and then after using the model analysis, the recognition of the speed limit is recognized as 40. in fig. 18 we observe four sign boards and system recognizes all traffic signs accurately. in fig. 19, we observe that the vehicle is turning, and, in the process, it detects all the signs but fails to recognize the speed signal and gives a value of 80, instead of 60. this can be due to the angle at which the camera is reading the value. several traffic signs with higher classification error rate can be seen, as shown in table 6. table 6. higher classification error rate sign type error rate crosswalk 7.22% no-vehicle lane 5.53% no parking 2.24% no entry 1.56% pedestrian walk 1.54% table 6 shows that several traffic signs with higher classification error rate are caused by the smaller proportion of main color. when training svm classifiers, most of the sample sets come from real-time urban road scenes, considering all the unfavourable factors such as weather, light conditions, and deformation. even then the recognition effect is better. at the same time, svm supports small sample training and has strong generalization ability and ensures the experiment results at higher accuracy. table 7. this paper and other literature comparison results study system image size processing time (ms) reference [18] 3.33ghz intel core i5 640 × 480 50 reference [19] 2.4 ghz intel core 2 with 4 gb ram 1355 × 781 detection: 400 reference [20] intel core i7-930 with 3 gb ram 640 × 480 180 this paper intel core i5 with 4 gb ram 1920 × 1080 detection: 25 classification : 10 as shown in table 7, comparing the average single-frame processing time of traffic sign recognition system with other fig. 17. on-road traffic sign recognition fig. 18. multiple traffic signs detection and recognition fig. 19. road turning sign error (svm) bhutto jaseem ahmed (et al.), urban road traffic sign detection and recognition with time space relationship model (pp. 22 33) sukkur iba journal of emerging technologies sjet | vol. 4 no. 1 january – june 2021 32 literature processing time, we can see that the average processing time of single-frame algorithm is lower than dealing with larger resolution. that is to say, this traffic sign recognition system can meet the requirements of real-time processing. 6. conclusion detection and recognition of road traffic sign is an important part of the modern intelligent transportation systems. its effectiveness lies in warning the driver with any possible mishap on the road. defined in this research work is an innovative and robust time space relationship model for the urban road traffic signs detection and recognition from a moving vehicle with high accuracy and efficiency. color and shapes are used for the traffic signs detection in addition to support vector machine (svm) for recognition. the research has contributed towards developing a framework which uses fast color segment algorithm to extract the traffic sign candidate regions, hence reducing the computational load. additionally, it also verifies the traffic sign candidate areas to decrease false positives and raise the accuracy by analyzing the variation in preceding video-images sequence while implementing the proposed time space relationship model. the findings of the research reveal that the proportion of positive detection and recognition of road traffic sign is above 95.8%. furthermore, the research framework achieved better accuracy, efficiency, and the robustness in real time. 7. recommendation although the accuracy and real-time performance of the traffic sign recognition system in current study can meet the requirements, there are still areas for improvement. the time space relationship model can further be improved to decrease the false positive and high positive recognition can implement the multi-layer cnn architecture to achieve high accuracy. furthermore, the study can be applied over the mobile system efficiently. in the future, technologies such as cloud computing and data mining can be used to analyses and excavate the massive data provided by the mobile terminal and contribute to the future intelligent transportation system. author contribution bhutto jaseem ahmed: conceptualization, methodology, software, data curation, writing original draft, writing review & editing. qin bo: conceptualization, methodology, resources, supervision, project administration, funding acquisition. qu zabo: software, validation, formal analysis. zhai xiaowei: software, investigation visualization. abdullah maitlo: writing review & editing. data availabilty statement the datasets generated during and/or analyzed during the current study are not publicly available since the datasets are sole property of cgiv lab, computer science and technology department, ocean university of china, china. however, these datasets are available from the corresponding author on reasonable request and can be shared if permission is granted from lab. conflict of interest the authors of this paper declare no conflict of interest. funding this research received no specific grant from any funding agency in the public, commercial, or non-profit sectors. acknowledgment the support of the “computer graphics, image-processing and vision (cgiv) lab” established in department of computer science and technology, ocean university of china is hereby acknowledged. we would also like to show our gratitude to the anonymous bhutto jaseem ahmed (et al.), urban road traffic sign detection and recognition with time space relationship model (pp. 22 33) sukkur iba journal of emerging technologies sjet | vol. 4 no. 1 january – june 2021 33 reviewers for their so-called insights. we are also immensely grateful to ms. humera wagan (communication security officer) for her critical comments on an earlier version of the manuscript that greatly improved the manuscript. references [1] fleyeh, h., 2006. shadow and highlight invariant colour segmentation algorithm for traffic signs. in: cybernetics and intelligent systems, 2006 ieee conference on, pp. 1–7. [2] gomez-moreno, h., maldonado-bascon, s., gil-jimenez, p. and lafuente-arroyo, s., 2010. goal evaluation of segmentation algorithms for traffic sign recognition. ieee transactions on intelligent transportation systems 11(4), pp. 917 – 930. [3] shadeed, w.g.; abu-al-nadi, d.i.; mismar, m.j. road traffic sign detection in color images. in proceedings of the 2003 10th ieee international conference on electronics, circuits and systems (icecs2003), sharjah, uae, 14–17 december 2003; pp. 890–893. [4] li, h., sun, f., liu, l. and wang, l., 2015. a novel traffic sign detection method via color segmentation and robust shape matching. neurocomputing 169, pp. 77–88. [5] barrile, v., meduri, g. m. and cuzzocrea, d., automatic recognition of road signs by hough transform: road-gis. journal of earth science & engineering, vol. 2, 2012, pp. 4250. [6] landesa-vazquez, i., parada-loira, f. and alba-castro, j., 2010.fast real-time multiclass traffic sign detection based on novel shape and texture descriptors. in: conference record – ieee conference on intelligent transportation systems, pp. 1388–1395. [7] liu, c., chang, f. and chen, z., 2014. rapid multiclass traffic sign detection in highresolution images. ieee transactions on intelligent transportation systems 15(6), pp. 2394–2403. [8] heng, l., lee, g. h., fraundorfer, f. and pollefeys, m., 2011. real-time photo-realistic 3d mapping for micro aerial vehicles. in: ieee/rsj international conference on intelligent robots & systems ieee/rsj international conference on intelligent robots & systems, pp. 4012–4019. [9] crandall, d., owens, a., snavely, n. and huttenlocher, d., 2011. discrete-continuous optimization for large-scale structure from motion. in: ieee conference on computer vision & pattern recognition, pp. 3001–3008. [10] golparvar-fard, m., balali, v. and garza, j. m. d. l., segmentation and recognition of highway assets using image-based 3d point clouds and semantic texton forests. journal of computing in civil engineering, 2012, 29. [11] yang m., gu x., lu h., wang c. and ye l., 2015. panorama-based multilane recognition for advanced navigation map generation. mathematical problems in engineering 2015, pp. 1–14. [12] riveiro, b., diaz-vilarino l., conde-carnero, b. and soilan, m., 2015. automatic segmentation and shape-based classification of retro-reflective traffic signs from mobile lidar data. ieee journal of selected topics in applied earth observations & remote sensing pp. 1–9. [13] yu, y., li, j., wen, c., guan, h., luo, h. and wang, c., 2016. bag-of-visual-phrases and hierarchical deep models for traffic sign detection and recognition in mobile laser scanning data. isprs journal of photogrammetry & remote sensing 113, pp. 106–123. [14] ashish-pradhan. network traffic classification using support vector machine. international journal of computer applications · october 2011. [15] traffic sign detection and positioning from google street view streamlines. victor j. d. tsai. asprs 2015 annual conference tampa, florida may 4-8, 2015. [16] radu timofte, victor adrian prisacariu, luc van gool, and ian reid. combining traffic sign detection with 3d tracking towards better driver assistance. world scientific review volume – 9. march 23, 2011. [17] j. greenhalgh, m. mirmehdi. real-time detection and recognition of road traffic signs. intelligent transportation systems ieee transactions on, 2012, 13(4):14981506. [18] 汤凯, 李实英, 刘娟,等. 基于多特征协同的交通标志检测[j]. 计算机工程, 2015, 41(3):211-217 [19] houben s, a single target voting scheme for traffic sign detection. in: intelligent vehicles symposium. ieee, 2011:124-129. [20] gu y, yendo t, tehrani m p, fujii t, tanimoto m. traffic sign detection in dualfocal active camera system. in: ieee intelligent vehicles symposium germany, 2011, 1054–1059 https://www.researchgate.net/journal/0975-8887_international_journal_of_computer_applications https://www.researchgate.net/journal/0975-8887_international_journal_of_computer_applications format template vol. 1, no. 2 | july december 2018 sjet | issn: 2616-7069 | vol 1 | no. 2 | © 2018 sukkur iba 1 a novel asymmetric three phase multilevel inverter with reduced switches mafaz ahmed 1,tila muhammad2,rafi uzman3,omais khan2 abstract: multilevel inverters (mli) are the most reliable and suitable inverters for medium and highpower applications. these inverters reduce the total harmonic distortion. there exist many types of single and three-phase multilevel inverters which are used in industries. the main issue of these multilevel inverters is use of an excess number of switches, which introduces the in-system losses, complexity of circuit, size, and cost etc. there are many novel topologies of multilevel inverter which are addressing the same issues. this paper anticipated a new topology of asymmetric cascaded multilevel inverter (mli). this novel topology can be used for single, three and multi-phase inverters and is most suitable for medium and high-power applications. to demonstrate the working of this novel topology in detail, its modes of operation are also explained. the validity of this inverter is tested for both resistive and inductive load. due to the utilization of very limited switches, gate drivers and dc voltage sources, it is found that this topology is low cost, simple and efficient inverter. keywords: three phase multilevel inverter, cascaded multilevel inverter, medium power, and high-power converters, asymmetric multilevel inverter, reduce switches. 1. introduction multilevel inverters (mli) synthesize several dc voltage sources to produce staircase output having desired multilevel waveform [1-3]. multi-level inverters are the modification of basic bridge inverters. they are normally connected in series to form stacks of level. multilevel inverters (mli) are widely used in medium power and high-power applications [4-6]. there is a lot of interest in multilevel inverters due to its usage in renewable energy resources [7]. total harmonic distortions (thd) in mli are low. that is why they are also preferable for industrial motor drives [8]. mli are also used 1 electrical and computer engineering department, air university, islamabad, pakistan corresponding author:mafazahmed65@gmail.com 2 department of electrical engineering, international islamic university, islamabad, pakistan 3 department of electrical engineering, abasyn university, islamabad, pakistan in flexible transmission system, where it is a core component of statcoms. multilevel inverters (mli) exist as single, three and multi phases in industry. in this paper, we targeted three phase inverters. three classical topologies of mli are: (a) neutral point clamped mli (npc) [9], (b) cascaded hbridge mli (chb) [10, 11], and (c) flying capacitors mli (fc) [12]. type (a), cascaded h-bridge is the most favorable among these three classical topologies for applications requiring many levels. type (b) neutral point clamped inverter (npc) are used in applications requiring lesser number of output levels. type (c) flying capacitors topology has the advantage of modular structure, minimum mailto:mafazahmed65@gmail.com mafaz ahmad (et-al), a novel asymmetric three phase multilevel inverter with reduced switches (pp. 1 11) sukkur iba journal of emerging technologies sjet | volume 1 no. 2 july – december 2018 © sukkur iba university 2 requirement of dc voltage sources and lowcost components. due to large interest in cheaper, reliable, and better quality multilevel inverters a lot of research is ongoing to design optimum multilevel inverters. research areas like reducing numbers of switches and others power components in converters design is one of the most interested area for researchers [1, 8, 13, 14], while number output voltage levels of the inverter are not disturbed. by growing the number of output levels in inverter, the harmonic distortion reduces, and hence output waveform quality improves. with increase of output levels, the number of switches also increases dramatically. the increase number of switches reduces efficiency, while increases size, complexity, and cost of the system. in this research, a novel asymmetric mli topology is anticipated to achieve desired output levels with fewer number of switches and gate drivers. a work like this research is listed in [10, 15, 16]. the proposed design is based on a modified version of cascaded topology; therefore, hereafter discussions is restricting to the cascaded topologies only. fig. 1. the unit cell of mli the number of bridges required in the chb inverter is proportional to the number of output staircase levels. the mathematical relationship between number of levels (nl) and number of bridges (nb) required is given as: 𝑁𝐵 = 𝑁𝐿 −1 2 (1) nl can be any odd integer greater than three. similarly, the total number of switches required nt are: 𝑁𝑇 = 4𝑁𝐵 (2) by combining equations 1 and 2 number of required transistors can also be represented as: 𝑁𝑇 = 2(𝑁𝐿 − 1) (3) the topological structure of mli must have the capability to deal with the following points  capability to sustain high input voltage such as hvdc  mli must have less switching devices as possible.  low switching frequency for mosfet’s/igbt’s due to multilevel approach. similar work is presented in [15] which also addressed the importance of reduction of switches and anticipated a novel mli with reduced number of switches. as proposed in [15] it is concluded that for addition of a new source to increase a positive and a negative level two transistor switches are required in the case of symmetric mli. for the ease of access, the unit cell used in [15] to increase 2 levels of the output is depicted in figure 1. it is clear from the figure 1 that s1 and s2 are the required two switches while the vdc is the voltage to be synthesis with the output. a similar work is also presented in [16] where the proposed inverter also synthesis two levels with a single switch with the output but the transistor used in that topology is a bidirectional switch, where two transistors are connected back to back. while comparing the inverter proposed in this research is using only unidirectional switch along with only an additional switch. in the similar way the unit cell used in this research (asymmetric cascaded mli) is consist of a voltage source, a transistor and a diode as shown in figure 2. hence one transistor in the inverter of [15] is replaced with a diode. the replacement of transistor with diode is giving good results in many aspects. the most prominent advantages are no turn on and off of diode are required. therefore, it decreases the complexity of mafaz ahmad (et-al), a novel asymmetric three phase multilevel inverter with reduced switches (pp. 1 11) sukkur iba journal of emerging technologies sjet | volume 1 no. 2 july – december 2018 © sukkur iba university 3 control signals. the diode is more robust than transistors. high power rating diodes are usually more easily available than transistors, it also decreases the cost of inverters because usually diodes are cheaper than transistors. furthermore, the diodes do not need any driver circuitry, therefore, it further reduces the cost, size, and complexity of the circuit. this proposed design is further explained in detail in the section ii of this paper. fig. 2. unit cell of the proposed asymmetric cascaded mli table i shows comparison between classical cascaded topology, diode clamped mli topology and proposed novel mli topology. the number of switches is quite less than those of the two other topologies as shown in table i. number of levels increases with the number of switches increases drastically. on the other hand, novel mli topology requires only one switch to introduce new level. according to the above discussion and calculation the following table shows the relation between the classical cascaded hbridge inverter, the reduced switches inverter discussed in [15] and proposed multilevel inverter topology. this research is organized such as, section 2 explains the proposed design. section 3 explains the modes of operation, while in section 4 the design is validated using simulations. in section 5 the modulation technique has been discussed. in section 6 the design is tested for inductive load. in section 7 hardware implementation has been discussed section 8 the conclusion has been made and at last future work has been proposed. 2. proposed multilevel inverter topology this research proposed a new topology of asymmetric cascade mli in which two levels (one positive and one negative) are added to output by the addition of a single transistor and diode as shown in figure 3. although this topology is general and can be extended to any levels here just for simplification we limited our discussions to 5 levels. for five levels output our topology requires an hbridge (consisting of four transistors), one diodes and one transistors (along with anti-parallel diode) switches as compared to classical inverter that requires 8 transistors, this new design significantly reduces the number of required switches and the number of gate drivers along with another required circuitry. comparison has been shown in table ii. mafaz ahmad (et-al), a novel asymmetric three phase multilevel inverter with reduced switches (pp. 1 11) sukkur iba journal of emerging technologies sjet | volume 1 no. 2 july – december 2018 © sukkur iba university 4 table i. comparison of topologies with reduced switches table ii. comparison of topologies with reduced switches diode clamped mli flying capacitor mli cascaded mli mli with reduced switches no. of switches 8 8 8 5 no. of clamping diodes 8 0 0 1 no. of floating capacitors 0 8 0 0 no. of dc bus capacitors 4 4 2 2 fig. 3. asymmetric cascaded mli the number of transistors switches (nt) for any desire levels can be found as: 𝑁𝑇 = 𝑁𝐿 −3 2 + 𝑁𝐵 (4) where nl is the number of desired staircase output levels and nb is denote as the number of transistors in h-bridge. to generate multi-level output the design requires isolated dc voltage sources and diodes. these isolated dc sources to synthesis and number of extra diodes is a function of output levels which can be formulated as: 𝑉𝐷𝐶 = 𝑁𝐿−3 2 + 1 (5) 𝑁𝐷𝐿 = 𝑁𝐿 −3 2 (6) 𝑁𝐹𝐷 = 𝑁𝑇 (7) where, vdc stands for isolated dc voltage sources and ndl represents number of diodes requires for addition of levels to the output. in addition, freewheeling diodes (nfd) require are also given by equation 4. 2.1. case study: nine level inverter in this section, a single phase of the proposed design is explained by considering the case of nine levels output. by using equations 4, 5, 6 and 7 we found number of transistors, freewheeling diodes. figure 3 shows the circuit diagram of the five levels mli. the design is validated by using simulations presented in section iv which is no. of levels classical cascaded hbridge topology a diode clamped topology b proposed reduced switches cascaded topology b number of transistors number of drivers number of transistors number of drivers number of transistors number of drivers 5 8 8 8 8 5 5 7 12 12 12 12 6 6 11 20 20 20 20 8 8 13 24 24 24 24 9 9 n 2n-2 2n-2 n+3 n+3 (n-3)/2+4 (n-3)/2+4 mafaz ahmad (et-al), a novel asymmetric three phase multilevel inverter with reduced switches (pp. 1 11) sukkur iba journal of emerging technologies sjet | volume 1 no. 2 july – december 2018 © sukkur iba university 5 table iii. switching scheme s1 s2 s3 s4 s5 output voltage on off off on off vdc1 on off off on on vdc1 +vdc2 off off off off off 0 off on on off off -( vdc1) off on on off on -(vdc1 +vdc2) fig. 4. driver circuitry also tested for inductive load presented in section vi. the working principle of the design is explained in next section. 2.2. gate circuitry tlp 250, like other drivers has an input stage, output stage and the input power source. it is optically isolated driver, means that input and output are optically isolated. figure 4 shows the diver circuitry. 3. working principle table iii shows the switching scheme of the novel single phase five level asymmetric cascade mli topology, given in figure 3. the working of the design is explained by using five modes, where positive half cycle is explained by using modes 0 to 2. negative cycle is explained by using modes 3 to 4. 3.1. positive half cycle the positive half cycle is given in figure 5. to achieve the waveform of figure 5, the entire procedure and switching scheme is divided into three different modes, which are discussed below in detail with heading mode 0 to mode 2. fig. 5. positive half cycle mode 0: in this mode no switch is conducting, so the output voltage is v=0 which is shown in figure 6 and its output is highlight with m0 in figure 5. mode 1: in this mode switch 1 and switch 4 are in on state, along with diodes 1 that is in forward conducting mode. the voltage source vdc1 is connected to load as shown in figure 7 and figure 5 shows first stair in output appears as m1. mode 2: in this mode of operation, diode d1 is turned off while switch 5 has been turned on in addition to previous switches. in this mode two voltage sources vdc1 and vdc2 add up and are connected to the load as shown in figure 8 and output stair is highlighted with m2 in figure 5. mode 2 completes the positive half cycle; the next positive half cycle is generated by reversing the aforementioned modes in which the output level decreases gradually and at last reach to zero level in which no source is m0 m1 m2 mafaz ahmad (et-al), a novel asymmetric three phase multilevel inverter with reduced switches (pp. 1 11) sukkur iba journal of emerging technologies sjet | volume 1 no. 2 july – december 2018 © sukkur iba university 6 connected to the load using transistors. in this case, if the load is inductive, the stored energy can be sent back to the sources using freewheeling diodes. 3.2. negative half cycle similarly, to the positive half cycle the level of the inverter increases in negative region by adding the dc voltage sources with load in reverse polarity. the output levels are shown in figure 12. the whole process and switching scheme utilized in generating of negative half cycle is explained in detail in mode 3 and mode 4. fig. 6. mode 0 fig. 7. mode 1 fig. 8. mode 2 fig. 9. mode 3 fig. 10. mode 4 mode 3: in this mode switch 2 and switch 3 are turned on, while the diode 1 is in forward conducting state as shown in figure 9 with this switching scheme the voltage source vdc1 appears across the load with negative polarity that is vout = -v as shown in fig 12, which is highlighted as m3. mode 4: in this mode, switch 5 is conducting, while the diode d1 is turned off and the remaining switches are in same state of conduction as that of mode 4. so, the sum of dc voltage sources vdc1 and vdc2 connect to the load with negative polarity as shown in figure 10 and figure 12 shows the output as m5. mode 4 completes the negative half cycle of the staircase output; the next negative cycle is generated by reversing the modes in which the output level decreases gradually from negative peak value and at last reach to zero level in which no dc voltage source is connected to the load using transistors. mafaz ahmad (et-al), a novel asymmetric three phase multilevel inverter with reduced switches (pp. 1 11) sukkur iba journal of emerging technologies sjet | volume 1 no. 2 july – december 2018 © sukkur iba university 7 fig. 11. single phase of five level multilevel inverter fig. 12. negative half cycle of output fig. 13. simulation results five level single phase multilevel inverter all the above 5 modes discussed for 5-level multilevel inverter. simulation results for 5level mli has been discussed in the coming sections. 4. simulation the novel mli design has been validated by using matlab/simulink toolbox. simulation has been performed for the design given in figure 3 for generating five levels output. figure 11 shows the simulation model of proposed novel single phase mli. in the simulation for five level mli, five switches and one diode are used. the staircase waveform for resistive load is shown in the fig 13. this makes the output wave form to look like sine wave, the width of the output stairs is different. m3 m4 mafaz ahmad (et-al), a novel asymmetric three phase multilevel inverter with reduced switches (pp. 1 11) sukkur iba journal of emerging technologies sjet | volume 1 no. 2 july – december 2018 © sukkur iba university 8 fig. 14. three phase asymmetric cascaded mli in the similar way, proposed design of five level three phase multilevel inverter has also been implemented using matlab simulink. the three-single phase mli of figure 14 are connected in parallel to generate 3-phases as shown in figure 16. the simulation results are shown in figure 16 is the out from phase to neutral. fig. 15. carriers signals for mli 5. sinewave pulse width modulation (spwm) to regulate the output and control different parameters of inverters modulation techniques are used [20]. there are many types of modulation techniques for the modulation of the proposed mli [21-22]. here to verify the validity of modulation in the proposed mli, shifted carrier based spwm is selected and used. alternate phase opposite disposition (apod) has been used for modulation as shown in figure 15. in apod modulation all carriers are in phase that are above the zeroreference level but are opposite to triangular signals below zero reference. normally four triangular signals will be required, but for this topology, three triangular signals are sufficient. switch 5 is on in both intervals (+ive and -ive), so, it required one triangular signal. the test is conducted by using carrier frequency 20 khz while the modulated frequency is 50 hz and for nine level mli. here the carriers are the triangular waves while the modulated signal is a reference sine wave. the carriers are compared with the reference sine wave and the desired switching pattern of transistor gate signal is generating. the modulated output wave form for single phase is given in figure 17 and for three phase outputs is shown in figure 16. figure 18 shows the harmonic analysis of mli. the total harmonic distortion is 5.82%. mafaz ahmad (et-al), a novel asymmetric three phase multilevel inverter with reduced switches (pp. 1 11) sukkur iba journal of emerging technologies sjet | volume 1 no. 2 july – december 2018 © sukkur iba university 9 fig. 16. three phase mli spwm modulated output fig. 17. spwm modulated output waveform fig. 18. hamonic analysis fig. 19. output wave with inductive load 6. validity for inductive load the validity of the proposed mli is also tested for inductive loads. fig 19 shows the simulation model with inductive load. there are anti-parallel diodes with each transistor which is working as the freewheeling diode when the reverse e.m.f. produces during switching in the presence of inductive load. 7. hardware implementation a prototype has been developed for the proof of concept of proposed mli. this prototype of inverter is given in figure 20. the triangular and reference sine wave are generated by using op-amp ics while for the comparison of the two signals comparator ics are used. probe has been set with 10x and vertical sensitivity is 1 volt/cm. 𝑉𝑝−𝑝 = 50 𝑉 𝑉𝑝 = 50 2 𝑉 𝑉𝑝 = 25 𝑉 figure 20 shows the three-phase implementation of five level multilevel inverter. second shelf has the push pull inverter for low voltages (24 low voltage supplies). third shelf has the circuit for mafaz ahmad (et-al), a novel asymmetric three phase multilevel inverter with reduced switches (pp. 1 11) sukkur iba journal of emerging technologies sjet | volume 1 no. 2 july – december 2018 © sukkur iba university 10 switching signals. the output wave of the prototype is given in the figure 21. due to unavailability of three channel oscilloscope only single-phase output is given in figure 21. fig. 20. three phase multilevel inverter prototype fig. 21. single phase output of mli prototype 8. conclusion the novel topology of an asymmetric cascaded mli has been proposed that has less number of switches. the design reduces switch losses and is more cost effective. therefore, the number of driver circuit is also reduced, as well as low dv/dt stress on individual switch and switching losses is reduced. as the number of power components decreases, the cost decreases, the design becomes simpler and size of the system also reduces. the design can be used to generate output waveform with any desired number of levels. the proposed design has been validated by simulations considering resistive as well as inductive loads. 9. future work more modulation techniques like shepwm, shmpwm, etc. can be applied to this novel topology to further reduce total harmonics distortion thd. references [1] f. z. peng, w.qian, and d.cao, "recent advances in multilevel converter/inverter topologies and applications," in power electronics conference (ipec), 2010 international, 2010, pp. 492-501. [2] s. kouro, m. malinowski, k. gopakumar, j. pou, l. g. franquelo, b. wu, et al., "recent advances an industrial application of multilevel converters," industrial electronics, ieee transactions on, vol. 57, pp. 2553-2580, 2010. [3] s. khomfoi and l. m. tolbert, "multilevel power converters," power electronics handbook, pp. 451482, 2007. [4] h. abu-rub, j.holtz, j. rodriguez, and g. baoming, "medium-voltage multilevel converters—state of the art, challenges, and requirements in industrial applications," industrial electronics, ieee transactions on, vol. 57, pp. 2581-2596, 2010. [5] l. g. franquelo, j. rodriguez, j. i. leon, s. kouro, [6] r. portillo, and m. a. prats, "the age of multilevel converters arrives," industrial electronics magazine, ieee, vol. 2, pp. 28-39, 2008. [7] b. wu, high-power converters and ac drives: john wiley & sons, 2006. [8] t. muhammad, a. u. khan, n. jamil, j. zameer, and m. khawar, "dc voltage regulator for battery less pv system using mppt," in power generation system and renewable energy technologies (pgsret), 2015, 2015, pp. 1-6. [9] f. khoucha, s. m. lagoun, k. marouani, a. kheloui, and m. el hachemi benbouzid, "hybrid cascaded h-bridge multilevel-inverter inductionmotor-drive direct torque control for automotive applications," industrial electronics, ieee transactions on, vol. 57, pp. 892-899, 2010. [9] a. nabae, i. takahashi, and h. akagi, "a new neutral-point-clamped pwm inverter," industry applications, ieee transactions on, pp. 518-523, 1981. [10] m. chithra and s. b. dasan, "analysis of cascaded h bridge multilevel inverters with photovoltaic arrays," in emerging trends in electrical and computer technology (icetect), 2011 [11] international conference on, 2011, pp. 442-447. k. prasad, g. r. kumar, t. v. kiran, and g. s. narayana, "comparison of different topologies of cascaded h-bridge multilevel inverter," in computer communication and informatics (iccci), 2013 international conference on, 2013, pp. 1-6. [12] s. bernet, d. krug, s. s. fazel, and k. jalili, "design and comparison of 4.16 kv neutral point clamped, flying capacitor and series connected hbridge multi-level converters," in industry mafaz ahmad (et-al), a novel asymmetric three phase multilevel inverter with reduced switches (pp. 1 11) sukkur iba journal of emerging technologies sjet | volume 1 no. 2 july – december 2018 © sukkur iba university 11 applications conference, 2005. fourtieth ias annual meeting. conference record of the 2005, 2005, pp. 121-128. [13] e. babaei, "a cascade multilevel converter topology with reduced number of switches," power electronics, ieee transactions on, vol. 23, pp. 2657-2664, 2008. [14] e. babaei, s. hosseini, g. gharehpetian, m. t. haque, and m. sabahi, "reduction of dc voltage [15] sources and switches in asymmetrical multilevel converters using a novel topology," electric power systems research, vol. 77, pp. 1073-1085, 2007. [16] “new cascaded multilevel inverter topology with minimum number of switches” elsevier ebrahimi, javad, ebrahim babaei, and gevorg b. gharehpetian. "a new multilevel converter topology with reduced number of power electronic components." ieee transactions on industrial electronics 59.2 (2012): 655-667. [17] kangarlu, m. farhadi, e. babaei, and s. laali. "symmetric multilevel inverter with reduced components based on non-insulated dc voltage sources." iet power electronics 5.5 (2012): 571581. [18] j. napoles, a. j. watson, j. j. padilla, j. leon, l. g. franquelo, p. w. wheeler, et al., "selective harmonic mitigation technique for cascaded hbridge converters with nonequal dc link voltages," industrial electronics, ieee transactions on, vol. 60, pp. 1963-1971, 2013. [19] “the essential role and the continuous evolution of modulation techniques for voltage source inverters in past, present and future power electronics” industrial electronics, ieee transactions on, … [20] kouro, samir, et al. "recent advances and industrial applications of multilevel converters." ieee transactions on industrial electronics 57.8 (2010): 2553-2580. [21] awais, muhammad, et al. "a novel problem formulation for selection of switching angles for minimization of total harmonic distortion in cascaded multilevel inverters." emerging technologies (icet), 2016 international conference on. ieee, 2016. [22] awais, muhammad, et al. "optimal switching angles for minimization of total harmonic distortion in single phase cascaded multilevel inverters." multi-topic conference (inmic), 2016 19th international. ieee, 2016.  vol. 1, no. 2 | july december 2018 sjet | issn: 2616-7069 | vol. 1 | no. 2 | © 2018 sukkur iba 66 efficient topology of voltage source inverter with reduced number of transistors iqbal tarique1, jahangir badar soomro1, ishfa taqi1, syed ali hyder1, faheem a. chachar1 abstract: an advanced topology of voltage source inverter has been introduced in this paper. the usage of low-cost switching devices such as thyristor give some edge to improved topology over conventional topology. the traditional topology requires six transistor, whereas on the contrary it possess only three high performance transistors. the conventional topology could prove to be expensive for high power applications where costly switching devices such as silicon carbide and gallium nitride are required thus, the new evolving topology could be more feasible for it. simulation and experimental results have been provided for further verification. keywords: efficient topology, inverter, vsi, transistor, thyristor 1. introduction semiconductor devices like bipolar junction transistors, mosfets, thyristors, triac and diac, etc. make our lives easier. they act as an intermediate between various forms of energies and convert one form of power into another form. these all small devices combine together and make a huge sea of revolutionary machines. initially electromechanical converters derived one form of energy into another form. inverter is basically a converter which convert dc power into ac power. the word “inverter” is derived from a class of power electronics circuits which could be able to operate from a dc voltage source or dc current source and convert it into ac voltage or ac current [1-3]. although it is not unusual that the input dc supply could get from the ac source the primary source is ac, it is converter from ac 1 sukkur iba university corresponding email: iqbal.be14@iba-suk.edu.pk to dc converter into dc form and then converted back to ac using an inverter. since the resultant output might be different in frequency and magnitude from the initial ac supply [4]. now a days, we use a common topology which we call it conventional topology here and it is shown in figure 1. it is widely used in many applications like uninterruptible power supply (ups), industrial motor drives, hvdc etc. this paper focused on the proposal of three-phase voltage source inverter (vsi) which has similar features compared to the conventional topology of six switches (transistor) in terms of voltagecurrent waveforms. in this paper, a topology is introduced which has a major reduction of transistors and instead of these inexpensive thyristors are used shown in figure 2. mailto:iqbal.be14@iba-suk.edu.pk iqbal tarique (et-al), efficient topology of voltage source inverter with reduced number of transistors (pp 66-75) sukkur iba journal of emerging technologies sjet | volume 1 no. 2 july – december 2018 © sukkur iba university 67 fig 1: schematic model of proposed topology fig 2: schematic model of conventional topology this paper discusses the proposed topology, its basic operation and switching technique. software implementation of the topology is implemented using matlab/simulink and also its experimental results are provided to analyse and verify its feasibility and performance. 2. proposed topology inverters are power electronics converters which convert direct current (dc) into alternating current (ac) utilized extensively in many applications such as induction heating, variable speed ac motor derives distributed generation (dg) and uninterrupted power supplies (ups). semiconductor electronic switches are one of the major components of the converter which essentially determine the complexity, cost and efficiency of the system. mostly, silicon-based power electronic switches are widely used in the market [5]. here the proposed novel topology of three leg voltage source inverter (vsi) (shown in figure 2) which possesses three semiconductor transistors unlike the conventional topology which contain six semiconductor transistors. this makes this topology cost effective [6]. thyristors are also present per phase to provide natural commutation therefore, there is no need of external commutation circuitry. this topology is more efficient and cost effective than conventional topologies of voltage source inverters (vsi). 3. commutation scheme for novel topology it includes switching elements like transistors and thyristors which require a proper switching technique to drive the required results. commutation speed of such devices could be controllable. direction of positive and negative current flow will be discussed in this section. only one phase of this topology will be elaborated here in order to understand its functionality properly [7]. a. basic commutation operation a) positive current control scheme i for positive cycle of current flow, thyristor stap will remain on while keeping the complimentary thyristor stan off. as shown in the figure 3(a). ii with the help of an appropriate pwm technique transistor sa will continuously turn on and off. iii positive current direction remains through stap, sa, d2, and dt2, in the whole positive current cycle. iv at zero crossing of a single period, the gate signal from transistor sa should be removed to turn off the thyristor stap iqbal tarique (et-al), efficient topology of voltage source inverter with reduced number of transistors (pp 66-75) sukkur iba journal of emerging technologies sjet | volume 1 no. 2 july – december 2018 © sukkur iba university 68 fig 3(a): current control scheme for single phase fig 3(b): current control scheme for single phase b) negative current control scheme i for negative cycle of current flow, thyristor stap will remain on while keeping the complimentary thyristor stap off. as shown in the fig 3(b). ii with the help of an appropriate pwm technique transistor sa will continuously turn on and off. iii current direction negative remains through stan, sa, d1, and dt1, in the whole positive current cycle. iv for remaining stages, the same process will be repeated with respect to their phase order. 4. switching states of novel topology this novel topology of vsi which contain three stages (three legs) has total eight active and zero voltage commutation stages like conventional topology. in figure 4(a) to figure 4(f), only the active elements and the path of current flow are elaborated here. these are the six active commutation stages. at each stage there is only single thyristor and a transistor will be turned on for conduction of a phase. on the other side, the opposite thyristor of the same stage cannot conduct. in figure 4(a) the thyristor of third leg is conducted while its complementary thyristor remains off. when thyristor of second stage in figure 4(b) is on, at that instance the other thyristors for positive current should be off. as shown in the figure 4(a) only one thyristor stcp is in conduction mode, while stap and stbp is turned off. the complimentary thyristors are switched on and fired off in accordance with the thyristor of same leg. as per the rule, when stcn is off stan and stbn should be fired on. however, the three transistors sa, sb, sc will be turned off when current reaches zero with respect to their phase. the path through thyristor stcp, stan, and stbn; transistor sa, sb, and sc; also, diode d1, d3, d6, dt1, dt3, and dt6 followed by the current at this stage. the next commutation scheme and current flowing paths are examined in figure 4(b) in which the active or conducted devices are shown. in addition, the pictorial description is present for the rest stages from figure 4(c) to figure 4(f). iqbal tarique (et-al), efficient topology of voltage source inverter with reduced number of transistors (pp 66-75) sukkur iba journal of emerging technologies sjet | volume 1 no. 2 july – december 2018 © sukkur iba university 69 (a) (b) (c) (d) (e) (f) fig 4: switching states of novel topology the firing sequence (switching scheme) for all thyristors and transistors are elaborated clearly in figure 5, where the dead period between the switching of thyristors present at the same leg (stap and stan, stbp and stbn, stcp and stcn) is specified by the red bold mark. the transistor present in each stage is continuously commutated on and off by an appropriate pwm techniques. when this switching pulse is removed from transistors, the dead period will be generated between the commutation sequences of thyristors. it behaves in a way that when triggering signal is removed from the transistor, the circuit acts as an open path at that time,current could not flow through the circuit. according to the commutation sequence the elimination of gate pulse from transistor switched off the thyristor and provided them an appropriate recovery time for the next stage. below the conduction periods of semiconductor devices are illustrated in an adequate way [8]. fig 5. conduction sequences of devices according to the way of commutation illustrated in fig 4(a) to fig 4(f), it can be analysed that the switching sequences are: stap.sa+stan.sa= 1 (1) stbp.sb+stbn.sb = 1 (2) stcp.sc+stcn.sc= 1 (3) the table i, elaborates the eight switching states of inverter. non-zero out ac line voltage generated by seven stages and the rest two stages: stage 1 and stage 8 generate zero ac line voltage. the resultant line to line ac output voltage have discrete values of vdc, 0, and –vdc. output line voltages are shown with respect to the conduction of their devices. iqbal tarique (et-al), efficient topology of voltage source inverter with reduced number of transistors (pp 66-75) sukkur iba journal of emerging technologies sjet | volume 1 no. 2 july – december 2018 © sukkur iba university 70 table i. switching states of devices 5. switching control scheme it is defined before that the transistors present at the middle of each leg is commutated on and off with any specific switching scheme. any commutation technique/triggering scheme could be utilized to provide gate pulses to the transistors. however, in this project a uniquely designed pwm scheme was generated through sine-triangle pwm scheme. in this method a primary sinusoidal waveform is compared with a triangular waveform. the same gate pulse is applied to the transistor during positive and negative cycle of waveform in order to provide commutation from positive to negative current of thyristor at each phase. for easily understanding the analytical behaviour, it is assumed that the delay between each phase of thyristor is eliminated. during the shifting from positive to negative cycle of current, the gate pulse provided to the transistor also have no dead time. at the end, combination of all these elements will result an appropriate control scheme. the control scheme is generated by the comparison of triangular carrier wave with sinusoidal waveform which is 1200 shifted from each other for each phase. a) stage 1 control scheme figure 6(a) shows the comparison of sinusoidal and triangular wave which results the generation of triggering pulse for middle transistor sa illustrated in figure 6(c) and figure 6(e). in addition, step pulse for firing thyristor stap and stan is elaborated in figure. 6(b) and figure 6(d) respectively. fig 6: switching control scheme for stage 1, 2 and 3 switching states devices output line voltages stap.sa stb.sb stcp.sc vab vbc vca 1 0 0 0 0 0 0 2 0 0 1 0 -vdc vdc 3 0 1 0 -vdc vdc 0 4 0 1 1 -vdc 0 -vdc 5 1 0 0 vdc 0 -vdc 6 1 0 1 vdc -vdc 0 7 1 1 0 0 vdc vdc 8 1 1 1 0 0 0 iqbal tarique (et-al), efficient topology of voltage source inverter with reduced number of transistors (pp 66-75) sukkur iba journal of emerging technologies sjet | volume 1 no. 2 july – december 2018 © sukkur iba university 71 b) stage 2 control scheme switching sequence for stage 2 could also analyze in the figure 6. in which figure 6(g) and figure 6(i) are exciting pulse for thyristor stbp and stbn respectively. the output switching gate pulse derived from the comparison of triangular and sinusoidal waveform as shown in figure 6 (f), could be examined in figure 6 (h) and figure 6 (j). here the sine wave has a phase difference of 1200 from previous stage [9-10]. c) stage 3 control scheme as mentioned earlier, figure 6 (k) reflects the comparison of sine triangle waveform where sine wave possesses 2400 phase shift than the sine wave used in first stage. figure 6(l) and figure 6(n) illustrate the thyristor triggering pulses (stcp and stcn). figure 6(m) and figure 6(o) illustrate the switching pulse of transistor. output current equations the output currents could be assumed that are: ia = io cos( ωot + φo ) (4) ib = io cos( ωot + φo 2𝜋 3 ) (5) ic = io cos( ωot + φo + 2𝜋 3 ) (6) output voltage equations the inverter output equation is considered as: ( 𝑉𝑎 𝑉𝑏 𝑉𝑐 ) = ( 𝑆𝑡𝑎𝑝 𝑆𝑡𝑎𝑛 𝑆𝑡𝑏𝑝 𝑆𝑡𝑏𝑛 𝑆𝑡𝑐𝑝 𝑆𝑡𝑐𝑛 ) ∗ ( 𝑉𝑝 𝑉𝑛 ) + ( 𝑆𝑎𝑝 𝑆𝑎𝑛 𝑆𝑏𝑝 𝑆𝑏𝑛 𝑆𝑐𝑝 𝑆𝑐𝑛 ) ∗ ( 𝑉𝑝 𝑉𝑛 ) (7) the value of s would be 1 when the respective switch is on. when the switch is turned off the value of s would be 0. equations for phase voltage by using sine-triangle pwm scheme equations for the phase voltages could be written as: vax = vo cos ωot = mvdc cos ωot (8) vbx = vo cos( ωot 2𝜋 3 ) = mvdc cos( ωot 2𝜋 3 ) (9) vcx = vo cos( ωot + 2𝜋 3 ) = mvdc cos( ωot + 2𝜋 3 ) (10) line-line three phase output voltages can be defined as: vab = vax – vbx = m √3 vdc cos (ωot + 𝜋 6 ) (11) vbc = vbx – vcx = m √3 vdc cos( ωot 𝜋 2 ) (12) vca = vcx – vax = m √3 vdc cos( ωot + 5𝜋 6 ) (13) in the above equations m = modulation index = vo / vdc vo = peak amplitude of output voltage [13]. hence, through these switching patterns it is understandable the working principle of three leg three phase voltage source inverter. 6. simulation results the novel topology is implemented using matlab/simulink shown in figure. 7. simulation has been performed to observe the output current, line voltages and total harmonic distortion (thd). all the switches and the components as ideal. simulation parameters taken for analysis are as follows: input dc voltage: 200 v (peak to peak) output inductance: 25 mh; output resistance: 10 ω; carrier frequency: 2400 hz: iqbal tarique (et-al), efficient topology of voltage source inverter with reduced number of transistors (pp 66-75) sukkur iba journal of emerging technologies sjet | volume 1 no. 2 july – december 2018 © sukkur iba university 72 fig 7:.matlab/simulink model of vsi thd without filter is 45.13% fig 8(a): thd of voltage waveform without filter fig 8(b): output current waveform without filter thd of current with rl load is 10.6% without filter. fig 8(c): current thd with rl load without filter after using filter, we get the results given below fig 9(a): voltage waveform after filtration thd of voltage waveform after filtration that is 3.03% fig 9(b): voltage thd after filtration iqbal tarique (et-al), efficient topology of voltage source inverter with reduced number of transistors (pp 66-75) sukkur iba journal of emerging technologies sjet | volume 1 no. 2 july – december 2018 © sukkur iba university 73 fig 9(c): current waveform after filtration current thd after filtration is 2.89% fig 9(d): current thd after filtration. finally, figure 8(a) shows the output threephase line voltages and figure 8(b) shows the output three-phase current waveform without filter. all the outputs are taken as a pwm technique which can be further improved by using different technique. also, results are shown with filter in figure 9(a) and figure 9(b) three-phase line voltages and thd of filtered voltage respectively. figure 9(c) and figure 9(d) shows three-phase filtered current waveform and thd of current waveform. 7. hardware results this novel topology of voltage source inverter is also implemented on hardware to verify the results extracted from the simulation. switches and components used to implement this topology are as following: input dc voltage: 12-30 v (peak to peak) output inductance: 10 mh; output resistance: 1 kω; output frequency: 50 hz; arduino uno: to give switching signal bt151: thyristor irg4bc40s: transistor pn-junction: diode fig 10(a): pcb board with components fig 10(b): circuit design on pcb board iqbal tarique (et-al), efficient topology of voltage source inverter with reduced number of transistors (pp 66-75) sukkur iba journal of emerging technologies sjet | volume 1 no. 2 july – december 2018 © sukkur iba university 74 fig 10(c): experimental result of output waveform fig 10(d): output voltage wave of novel topology after filtration fig 10(e): thd of filtered output voltage after getting output three-phase line voltages, it can be seen that this topology has the same features as the conventional topology in term of voltages. although the waveforms are slightly distorted, it can be improved by developing and utilizing better switching technique and control scheme. in addition, current wave form will be given soon by implementing new scheme. in future, some steps would be taken to make this topology in use for the domestic as well as commercial use. 8. conclusion voltage source (vsi) and current source inverters (csi) are widely utilized in various applications such as, adjustable speed drives (asd) for ac motors, induction heating, uninterruptable power supplies (ups), standby power supplies, electronic frequency changer circuits, distributed generation units, hvdc systems to name a few [11],[12]. from the above results of matlab/simulation as well as of hardware results, it can be seen that the novel topology of voltage source inverter has the same features in terms of voltage-current waveforms provided in both sections i-e simulation and hardware. although, some results are distorted, these distortions can be mitigated by using more appropriate switching schemes, controlling schemes and more authentic filtration methods. observed from above results, the novel topology has advantages of thd over the conventional inverter as well as it has an advantage of its application that it can be used for high power applications. furthermore, this topology can be expanded to the domestic purpose as conventional topology is tending for domestic purpose. as the novel topology can be an economical alternative for the domestic purpose, it has a benefit of low cost as compared to the conventional topology. by taking some serious initiatives, this topology can be introduced to the domestic market for the betterment of society. the main purpose of this paper was to realize the importance and advantages of novel topology of voltage source inverter over the conventional topology. iqbal tarique (et-al), efficient topology of voltage source inverter with reduced number of transistors (pp 66-75) sukkur iba journal of emerging technologies sjet | volume 1 no. 2 july – december 2018 © sukkur iba university 75 reference [1]. soomro, j., memon, t.d. and shah, m.a., 2016, november. design and analysis of single-phase voltage source inverter using unipolar and bipolar pulse width modulation techniques. in advances in electrical, electronic and systems engineering (icaees), international conference on (pp. 277-282). ieee. [2]. soomro, j., qasmi, e.a., chachar, f.a., ansari, j.a. and soomro, s.a., 2018, march. comparative analysis of level shifted pwm techniques for conventional and modified cascaded seven level inverter. in computing, mathematics and engineering technologies (icomet), 2018 international conference on (pp. 16). ieee. [3]. wang, f., shen, w., boroyevich, d., ragon, s., stefanovic, v. and arpilliere, m., 2009. voltage source inverter. ieee industry applications magazine, 15(2), pp.24-33. [4]. lee, b.k. and ehsami, m., 2001. a simplified functional simulation model for three-phase voltagesource inverter using switching function concept. ieee transactions on industrial electronics, 48(2), pp.309-321. [5]. f. bordry , d.aguglia,“definition of power converters”, cern yellow report cern [6]. n. mohan, w. p. robbin and t. undeland, “power electronic: converters, applications, and design”, 2nd ed. (book), new york: wiley, 1995. [7]. s. rafin, t.a. lipo, b. kwon, “a novel topology for a voltage source inverter with reduced transistor count and utilizing naturally commutated thyristors with simple commutation”, 2014. [8]. s. rafin, t.a. lipo, b. kwon, “performance analysis of the three transistor voltage source inverter. using different pwm techniques”, icpeecce asia 2015. [9]. lee, b.k. and ehsami, m., 2001. a simplified functional simulation model for three-phase voltagesource inverter using switching function concept. ieee transactions on industrial electronics, 48(2), pp.309-321. [10]. lee, y.h., suh, b.s. and hyun, d.s., 1996. a novel pwm scheme for a threelevel voltage source inverter with gto thyristors. ieee transactions on industry applications, 32(2), pp.260-268. [11]. n. mohan, w. p. robbin and t. undeland, “power electronic: converters, applications, and design”, 2nd ed. (book), new york: wiley, 1995. [12]. b. k. bose, “power electronics and variable frequency drives: technology and applications” (book), ieee press, 1997. design of a centralized intelligent expert system and contamination detection of tissue cultured sugarcane crop vol. 4, no. 2 | july –december 2021 sjet | p-issn: 2616-7069 |e-issn: 2617-3115 | vol. 4 no. 2 july – december 2021 47 design of a centralized intelligent expert system and contamination detection of tissue cultured sugarcane crop mujahid hussain memon1,2, arif karim, dr1. waheeduddin hyder2, fayaz ali dharejo3, munsif ali jatoi4, dr. beena naqvi1, faisal ghazanfar1, farhan aziz1 abstract the paper presents a design of cloud based iot enabled smart agriculture application for hitech tissue cultured sugarcane crop entitled “design of centralized intelligent expert system and contamination detection of tissue cultured sugarcane crop”. this expert system comprises of raspberry pi-4 (rpi), arduino-mega, gsm-modem (sim900) and sensormodules for monitoring and control of essential parameters of growth-rooms inside a tissue cultured laboratory. the parameters monitored are temperature, humidity and light intensity with artificial day light timing and control. moreover, ai-based health prediction suggests the detection of contamination of sugarcane crop, which has been applied at edge device. in addition, fire-smoke sensor and methane gas sensor are incorporated for fire protection and any disastrous situation. three numbers of webcams are attached to the rpi for monitoring growth and health of explants. this is to get meaningful insights of data for future decision making in maximizing crop yield and quality. an ai-model was developed for detection of contamination that predicts the health of tissue cultured sugarcane crop, which has also the beauty of image enhancement which is covered applying generative adversarial networks (gan)”. in this system, the rpi reads sensor's data through arduino and convert it to dataframe with timestamp and geo-tag. the data along with the captured images are sent to a centralize cloud application for applying data mining and artificial intelligence. due to the great need of sugarcane crop in pakistan, the plant tissue culture (ptc) technology has been incorporated with ai. the proposed system is aimed to be installed at established ptcgrowth-rooms for sugarcane crop so that domain experts can be connected to the cloud application for its monitoring, control and data analytics. in addition, the use of telepresence through cloud application will enable ptc-experts to provide assistance to the remote user and resolve their issues timely, thus extending ptc technology all over the country which will eventually lead to increase crop yield with quality in affordable price. 1 pakistan council of scientific and industrial research (pcsir) laboratories complex karachi, pakistan. 2 ilma university, karachi, pakistan. 3 university of chinese academy of sciences, haidian, beijing, china. 4 department of biomedical engineering salim habib university, karachi, pakistan. mujahid hussain memon et al. design of a centralized intelligent expert system and contamination detection of tissue cultured sugarcane crop (pp. 47 63) sukkur iba journal of emerging technologies sjet | vol. 4 no. 1 july – december 2021 48 keywords: artificial intelligence, deep learning, internet of things, tissue culture, sugarcan 1. introduction plant biotechnology is emerging domain with excessive scope in our country. in plant tissue culture (ptc) which is a subdomain of biotechnology, has very complex and dynamic environment for monitoring and control the growth of tissue cultured plants. the vital parameters to monitor and control are temperature, humidity and light intensity of the tissue culture growth room with artificial daylight timings. in addition, methane gas sensor and fire-smoke sensor are incorporated for fire protection and to avoid any mishap. three numbers of webcams are attached to the rpi for monitoring growth and health of explants. similarly, to predict the health of cultured plants, it has been a big challenge to detect disease of infected plants, where deep learning (dl) and machine learning (ml) methods have been utilized by researchers in agriculture sector for crop monitoring. this field has a potential need of utilization of ict due to the climate changes and biodiversity and involvement of big-data generated. the fundamental idea of proposed work entitled: “design of centralized intelligent expert system and contamination detection of tissue cultured sugarcane crop” is to predict the health of crop and facilitate the domain experts (ptc-experts) to collaborate and assist the remote users to mitigate the day to day issues. the work is also an effort to transform agriculture sector into industry 4.0. inside laboratory, small pieces of explants of sugarcane are used under controlled environment. the culture is initiated in 20 to 30 days on nutrient media with and without growth regulator. the growth of ex-plant depends upon maintenance of aseptic and controlled conditions e.g. temperature, humidity and light. after initiation of culture, the explants are subculture on multiplication media for multiplication of explant and later on incubated for 20 to 25 days under controlled environment. approximately 5 to 6 times subcultures are utilized for multiplication from a single explant. tissue culture plants are healthy, disease free and high yielding product. in order to get a huge amount of crop, there would be a need of several tissue culture growth rooms but due to scarcity of the scientific staff (domain experts), they cannot manage their visits for monitoring the cultured plants. to address this issue, a large numbers of cultured sugarcane growth rooms can be monitored remotely by sitting at a centralized point using a cloud-based application. keeping in view to utilize such expert system, artificial intelligence (ai) plays an effective role for health prediction of cultured plants. ai’s subdomain deep learning (dl) wrapper eases the design, training and development of models over many frameworks such as theano, tensor flow, torch, chainer, and keras. these frameworks decrease the efforts of ai engineers in dl but still the training of the model is not a piece of cake; it needs a huge amount of data. our proposed methodology is the utilization of cloud based expert system and health prediction of cultured plants using deep neural networks (dnn) aiming to monitor and making a system to take actions timely and virtual visits be performed using telepresence. 1.1. plant tissue culture technology it is an emerging field which has a great potential and scope in agriculture industry for studying and solving basic and applied problems in the field of plant biotechnology. for mass production of crop, the micropropagation and other in-vitro techniques are widely used in commercial horticulture and agricultural [1]. a small piece of a plant either from root, shoot, leaf, and even a single cell is cultured in an aseptic and controlled environment on nutrient media supplemented with or without growth regulator. this isolated small piece of plant is termed as explant. under controlled temperature, humidity, and light conditions the explant is micro-propagated to form a clone of the mother plant [2]. the explants after getting reasonable growth are transferred to the semi-controlled conditions in green house for acclimatization. healthy and disease-free plants are selected for tissue mujahid hussain memon et al. design of a centralized intelligent expert system and contamination detection of tissue cultured sugarcane crop (pp. 47 63) sukkur iba journal of emerging technologies sjet | vol. 4 no. 1 july – december 2021 49 culture. the crop yield and quality can be improved through tissue culture technique. in a continuous production environment, there should be multiple tissue culture labs near the actual growth site to develop good quality seeding material to get better yield. for mass production, a large numbers of ptc labs would be required in the remote areas along with designated ptc experts. the monitoring and control of temperature, humidity and light conditions are required for tissue culture lab to maintain a healthy culture in growth room. it will be impractical to monitor these conditions manually on large scale either due to shortage of skilled experts or frequently traveling and visiting ptc sites. 1.2. tissue cultured sugarcan sugarcane (saccharum officinarum l.) is a vivid member of poaceae family is a perennial grass. it is normally propagated in two modes either by seeds or vegetatively. it is vegetatively propagated by stem cutting, having two or three buds called sets, whereas advanced approaches belonging to in-vitro propagation was done by using apical or axillary bud and young leaf as an explant. the tissue culture of sugarcane from different regions of the world was not properly reported but the first published attempt to regenerate sugarcane crop through in-vitro technique was made by heniz and mee (1969) [1]. for the breeding purpose, it is also reproduced through seed propagation via flower (fuzz) [3]. sugarcane breeding institute (sbi) [4] is responsible for the development of its varieties, hence it is obtained after breeding which was raised from fuzz. in order to provide the quality production of sugarcane crop, the development of tissue cultured sugarcane crop for quick multiplication of disease-free yield is a significant step towards the field of biotechnology. for most micropropagation work the explant of choice is an apical or an axillary bud. usually, the explants are more responsive to culture treatments if they are collected during the period of active growth [5]. for sugarcane micropropagation, the best explant type tissue cultured sugarcane crop is shoot tips which enhance the growth of sugarcane top actively [6]. shoot tip of sugarcane which can be usually obtained from 3 sources: top of the actively growing cane, elongating axillary shoot from decapitated shoots and dormant axillary buds [1]. usually the flowers are not feasible for any technique due to its high variability. the availability of high quality and true-type-planting material of fresh varieties of sugarcane is a great challenge which poses constraint in rapid acceptance for commercial use. even well-accepted profitable and commercial varieties cultivation require an excellent seed to guarantee the better cane yield, sugar yield with disease-free crop[7]. furthermore, the traditional methods of cultivation uses three-budded set which always requires a large quantity of seeds, thus, costly, time-consuming and less productive; only 5 to 10 canes per seed. on the other hand, a tissuecultured seed can produce 30 to 50 canes [8]. in leading agricultural countries of asiapacific region like australia, india, and the philippines have already applied this technique for commercial use and these countries have been getting more benefits through rapid propagation and distribution of elite varieties. the development of tissue culture technology for rapid multiplication of disease-free planting material has been an important step towards high quality and mass production [9]. moreover, ptc techniques deliver an alternative process for multiplication and improvement of sugarcane crops [10]. in a short period and faster rate, micropropagation of cane for quality and phytosanitary planting material, ptc offers the best methodology. as compared to the traditional seed techniques, ptc technique can guarantee to increase the production by 20-35 times [11]. from one shoot a large number of plants are produced using the technique of micropropagation. these were mandatory as compared to 8.8 tons of cane seed in conventional methods for planting in an area of a hectare. thus, the multiplication ratio was 100-150 times using ptc as matched to 11-12 using conventional cane sets, prominent to a drastic reduction in seed cane prerequisite [12] kuar & sandhu [13] have experimented and worked on the shoot multiplication rates which were ranged mujahid hussain memon et al. design of a centralized intelligent expert system and contamination detection of tissue cultured sugarcane crop (pp. 47 63) sukkur iba journal of emerging technologies sjet | vol. 4 no. 1 july – december 2021 50 from 4 to 25 fold and resultantly with 97% survival rate, the complete plantlets were achieved in 157 days. 1.3. culture contamination in ptc techniques, the contamination is the presence of undesirable element that spoils cultured crop. contamination in tissue culture is originated from two sources, 1) the carryover of microorganisms in the tissues of explants or on its surface, 2) following inappropriate sop’s inside the laboratory [14]. in the sequence of plant production and its growth, the microorganisms may move in the tissues of the plant through a natural setting. however, where explants appear uncontaminated, it may be necessary to bulkup the material to provide adequate material for testing [15]. plants may thus develop or cultivate endophytic ‘floras’ of variable species composition consisting of inter and intracellular microorganisms including viroids, viruses, prokaryotes (bacterial and bacteria-like agents), and fungi. in establishing tissue cultures, subject on the explant consumption for propagation, possibly surface and endophytic microorganisms are carried over into culture. it must be mentioned here that the detection of contamination is the core research work of our study, where image processing with dnn would be studied and an ai-model would be developed in order to predict the health of tissue culture sugarcane crop. 2. previous work the work of pezhman taherei ghazvinei and et al. [16] using ml and ann presented “sugarcane growth prediction based on meteorological parameters”, where the parameters of the crop were obtained as data by field trials of selected sugarcane variety. their experiment is based on data regarding the comparative study of daily sugarcane growth within accumulative daily irrigation water. aman and et al. [17] presented "smart agriculture monitoring system using iot" based on "thingspeak" and "arm7". they monitored humidity, temperature and soilmoisture of the land used for the plants. he has worked on iot for analyzing the agricultural operations where he has proposed to get data of parameters like atmospheric, temperature and soil fertility, so the farm condition can be monitored remotely. although, the work of dandy and et al. [18] is only focused on temperature and humidity monitoring in tissue culture laboratory for banana crop. they have designed a prototype using arduino-uno for overall control and gsm modem for sms notification. he has termed the monitoring of temperature and humidity to maintain the fast growth and resistant to diseases and infection. traditionally, abeer a. elsharif and samy s. abu-naser [19] have worked on “an expert system for diagnosing sugarcane diseases” using clips and delphi languages they have developed a standalone desktop application and few signs have been described for selection, where one has to select the symptoms of a disease; hitherto no automation and ai was applied. similarly, noor hafizahand and et al. [20] have also presented a web-based system for monitoring of tissue culture growth rooms and send emails and sms alerts. sensors are also incorporated with database to monitor critical parameters for data analysis. the work of bashar alhnaity and et al. [21] utilized deep learning for tomato plant growth and yield prediction in controlled greenhouse environment. the ai model utilized is a new deep rnn (recurrent neural network) with lstm (long short-term memory) neuron model that targeted growth parameters applied on time series data. similarly, the work of mohsen hesami and et al. [22] incorporated support vector machine (svm) with genetic algorithm for modeling ptc procedures especially the effect of growth regulators on explants in embryogenesis. in another work ann (artificial neural network) has been used to predict media composition for callus growth [23]. a similar effort was also made by anna and et al. [24] after incorporating ann, support vector regression (svr), m5-prime regression trees, random forests (rf), and k-nearest neighbors for prediction of the crop. mujahid hussain memon et al. design of a centralized intelligent expert system and contamination detection of tissue cultured sugarcane crop (pp. 47 63) sukkur iba journal of emerging technologies sjet | vol. 4 no. 1 july – december 2021 51 3. problem statement plant tissue culture a subdomain of biotechnology has a great potential in our country that needs an intelligent monitoring system in order to bring this diligence towards industry 4.0 for vision 2025 applying information & communication technology (ict) to boost economy of the country. there is great need of its utilization both in private and public sectors which may be a billion dollar industry in the future. this industry has been facing the scarcity of experts in pakistan especially for monitoring systems of culturedplants growth rooms located remotely. the few experts cannot manage a number of laboratories / growth-rooms for monitoring and their frequent visits is almost impossible. in order to monitor growth-rooms, the parameters like temperature, humidity, light intensity, day-light timing, growth and health of explants is essential for an expert. moreover, a remotely located laboratory also needs additional sensors for protection, i.e. detection of fire-smoke and flammable gases. further, the growth-room needs temperature between 25 to 29°c depending on the type of explants. similarly, the growth and health of plants are required to monitor visually by domain experts. the growth rooms also need 24/7 electricity and alternate energy sources or a backed-up generator to keep the laboratory lightening and controlled temperature to run the system smoothly. the artificial lights are needed for a short-day period that is an alternative of a day light. finally, the domain experts will be facilitated to analyze the data at a centralized cloud-based application and would be able to observe the growth of explants and future decision would be taken remotely to maximize the quality of production. the proposed system is named as tissue culture laboratory management system (tclms). 4. material and methods pakistan has a great potential of applying ptc in agriculture sector which will eventually lead to socioeconomic development. this technique has been successfully used for different crops such as sugarcane, banana, rice, tomatoes and potatoes in developed countries. after the establishment of a laboratory, the real challenge is to monitor the environment of growth-rooms and explant for health and contamination. the domain experts regularly visit these sites for monitoring and examining the explant so that corrective measures can be carried out. meanwhile, they analyze collected data for getting results, however, their perception is far low from ai-based dss (decision support system). this paper is intended to serve the industry of biotechnology with an intelligent system tissue culture growth rooms of sugarcane crop which can be connected to a centralize application via wifi and gsmmodem, where ptc-experts will monitor the process remotely and perform required actions to run a number of growth room remotely. the edge-device (tclms) will send respective data and images to the cloud application. the attached 3nos. of cameras will send pictures of explants to the cloud as per configured sampling time. the environmental parameters are temperature, humidity, light intensity, daylight timing, fire-smoke and presence of methane gas. these parameters are essential for motoring the growth of explants and detection of any mishap situation to safeguard the laboratory. 4.1. hardware architechture hardware architecture the hardware architecture for “design of centralized intelligent expert system and contamination detection of tissue cultured sugarcane crop” is shown in fig. 7. there are two processing units, i.e. raspberry pi-4 (rpi) and arduinomega. rpi is responsible for gathering images from cameras (3nos.); connectivity through gsm &wifi; and finally acquisition of sensor’s data from arduino-mega. the arduino-mega and cameras are connected to rpi through usb port. similarly, the gsm modem (sim900) is attached to the serial port of rpi as shown in fig. 1. mujahid hussain memon et al. design of a centralized intelligent expert system and contamination detection of tissue cultured sugarcane crop (pp. 47 63) sukkur iba journal of emerging technologies sjet | vol. 4 no. 1 july – december 2021 52 fig.1. gsm modem (sim900) with on/off control circuit and rs232 driver circuitry for energy conservation. the rpi is powered by rechargeable battery (12v & 12a) with 5volt voltage regulator and charging circuitry. in case of power failure, the battery can run the tclms for ~10 hours. the second processing unit, i.e. arduino is utilized for collecting sensor’s data through i2c port. sim900 module is connected through max232 (serial driver ic) to serial port of rpi as shown in fig.1. the power is supplied to sim900 module through a transistor (d313) used for critical situation, i.e. when there is no wifi connectivity. this module is incorporated due to its feature of sending text and connectivity of internet for laboratories located in remote areas of different parts of country. the sensors utilized are methane / natural gas sensor (mq4), temperature and humidity sensor (sht-30), light sensor (gh170) and fire/smoke sensor (apolloxp95). fig. 2 adafruit sht-30 sensor for temperature & humidity measurement. the temperature sensor incorporated is sht-30 from adafruit. it is water proof and mesh protected. the connectivity to ardunio is established via i2c interface as shown in fig.2. fig. 3. mq4 methane/natural gas sensor module with 12-bit adc and i2c interface. for fire protection, i.e. detection of flammable gases, a methane / natural gas senor (mq-4 module) is utilized. it is connected to arduino via its i2c interface as shown in fig.3. the detection range is 300 to 10000ppm with temperature working range of -10 to 50°c. fig. 4. gh1750 ambient light sensor module with i2c interface. t the ambient light intensity measurement with bh1750 module having range of 1~65535 lux, is connected via i2c interface to the arduino as shown in fig.4. the average light requirement for a laboratory is 500~2000 lux. fig.5. fire smoke detector module with connections to prevent any mishap, the detection of flammable gases, fire and smoke detector (apollo xp95) is also integrated to detect flame or smoke as shown in fig.5. this will also send alerts via gsm-modem, to the mujahid hussain memon et al. design of a centralized intelligent expert system and contamination detection of tissue cultured sugarcane crop (pp. 47 63) sukkur iba journal of emerging technologies sjet | vol. 4 no. 1 july – december 2021 53 responsible person in order to take necessary actions. fig. 6 raspberry pi-4 connected with 03nos. of web-cams the integration of three nos. of webcams with rpi is shown in fig.6. these webcams will motor different explants simultaneously in growth-rooms located remote location. furthermore, to minimize the cost of servers, the images and sensors’ data are stored in rpi memory which is later on send to the cloud storage as per scheduled time. the cloud data will be utilized for data mining. fig. 7. hardware architecture of tclms 4.2. software architechture there are two main processing units, i.e. rpi and arduino mega which requires embedded software application for monitoring, control and connectivity to the cloud application. firstly, rpi is powered by raspberry pi os (previously known as raspbian). a software application in python is modeled as shown in fig.8. similarly, an application in c-language is modeled for arduino mega as shown in fig.9. fig. 8 overall state diagram of software application for rpi in the start after initialization of rpi with its os, it checks status of main supply 220ac and charge-level of battery. if main supply is present rpi switch the whole mujahid hussain memon et al. design of a centralized intelligent expert system and contamination detection of tissue cultured sugarcane crop (pp. 47 63) sukkur iba journal of emerging technologies sjet | vol. 4 no. 1 july – december 2021 54 system to take power from it. similarly, in case of main supply failure, it will switch to the battery (12v, 12a) backup, in addition if the battery is not charged enough i.e. below 25%, it will send sos signal via gsm modem to the concerned user indicating the current situation of power failure with low battery level. if the above stated conditions are satisfactory, the rpi will read data from arduino-mega which comprises data from various sensors attached to the system. the data presents overall picture of the laboratory which includes, level of methane gas, fire / smoke detection, temperature, humidity and ambient light intensity. if there is any sign of methane gas or fire and smoke, the rpi will declare fatal situation and send current status of the system to the concerned user or responsible person for initiating remedial action. rpi will keep on checking the fatal situation until it is fixed. in the next stage, the 03nos. of camera images are scanned for capturing images of the explants under observation. the images are captured after every 6 hours or as configured by the user. the sensors-data along with the images-data are transmitted via the rpiwifi and insured its proper reception at cloud application, i.e. resend data until acknowledged by cloud application. the overall state diagram is shown in fig.8 the software application for arduinomega monitors the attached sensors via i2c interface. all the sensors incorporated are i2 c compatible. the sensors are described in detail in the hardware architecture above. the sensors are scanned for every 5 minutes or as configured by the user. the individual sensor's data are aggregated and transformed into a data-frame, it is then sent to rpi on its request with insuring proper transfer by receiving acknowledgement from rpi. the arduino is connected to rpi via usb interface. the state diagram of software application for arduino is shown in fig.9. fig. 9 state diagram of software application for arduino. 4.3. data formation at device stclms the sensors data are transformed to a dataframe for sending it via gsm-modem or through rpi-wifi depending availability. start code sender id explant id payload (sensors-data with time stamp and geo-tag) crc end code fig. 10. data-frame sends by tclms device to cloud application mujahid hussain memon et al. design of a centralized intelligent expert system and contamination detection of tissue cultured sugarcane crop (pp. 47 63) sukkur iba journal of emerging technologies sjet | vol. 4 no. 1 july – december 2021 55 the data-frame is comprised of device-id explant-id, sensors-data and crc for checking frame integrity as shown in fig. 10. 4.4. data-frame formation by cloud application the cloud application performs data analytics, data mining and ai over the logged data. in response it sends alerts and control parameters to a specific tclms for smooth running of process in the ptc-growth rooms. the frame format is shown in fig. 11. it comprises sender-id (i.e. cloud-application), location-id (i.e. receiving tclms at a particular location) payload and crc for checking integrity of frame. 4.5. database tables for critical parameters the data collected from different parameters are transmitted to the cloud application and stored in the cloud database. the schema of database comprises three tables, i.e, expert system table, sugarcane variety type tables, and expert opinion table as shown in table. 1, 2 & 3 respectively. the plant type table represents the plant names that are under ptc process; it is also labelled, which part of the mother plant is taken for ptc-growth, which may be a piece from root, shoot, leaf or some other part. similarly, the expert system table represents as main table where data of different parameters would be stored. the monitoring, data-analytics and data-mining will help in identifying potential part of plant for ptcgrowth. table 1: a sample database for “expert system” time stamp loca tion id plant id tºc light (hrs) light (lux) humidity (rh) 01.10.2020: 11am 21 1 25 12 6500 62 01. 10.2020: 01pm 21 1 24 12 6450 61 01. 10.2020: 08pm 26 3 27 14 4500 72 -- -- -- -- -- -- -- table 2: a sample database for “sugarcane variety type” plant id plant name tºc light (hrs) light (lux) humidity (rh) 1 sugarcane variety 1 24 12 6000 60 2 sugarcane variety 2 25 16 7522 63 3 sugarcane variety 3 28 12~16 4500 70 - - - - - - table 3: a sample database for “expert opinion” timestamp es_id location id plant id expert opinion 01.10.2020: 11am 1 21 1 healthy 01. 10.2020: 01pm 1 21 1 healthy 01. 10.2020: 08pm 2 26 3 healthy - - - - - 4.6. data formation at device stclms there is a huge variety of cloud computing flavors to host the cloud application, but amazon web services (aws) provided by amazon is chosen to reduce the cost of software development time for the project. in aws, the elastic compute cloud (ec2) with ubunto is customized. it is free 12 months with hardware configuration of 1-gb ram and 8gb storage capacity [10]. the collected start code sender id location id payload (alerts, control parameters for a particular tclms at a particular location) crc end code fig. 11. data-frame sends by cloud application to tclms device mujahid hussain memon et al. design of a centralized intelligent expert system and contamination detection of tissue cultured sugarcane crop (pp. 47 63) sukkur iba journal of emerging technologies sjet | vol. 4 no. 1 july – december 2021 56 data from edge devices are stored in database (mongodb) at s3 bucket. in order to achieve such goals of real-time ai-model generation and monitoring its performance, aws facilitates a comprehensive and fully managed services that covers cloud computing environment including an instance, storage, machine learning workflow, device integrity, security and availability. aws also provides encryption by default during communication and storage in s3 bucket. the application would be deployed on aws-ec2 and required micro services including apis of application and rpi would be integrated with sagemaker. a microservice will fetche data from and to s3 bucket. to train the model, amazon provides ‘aws sagemaker’ development environment with notebook ide and sagemaker studio; a program-less environment for training, testing and creating ai model with readymade algorithms. sagemaker supports deep learning-based ai frameworks which include tensorflow, pytorch, apache mxnet, chainer, keras, gluon, horovod, scikit-learn and deep graph library. in addition to this, version control of dnns models has been carried out real time so that evaluation of different models be tested and compared. fig.12. topology of developed neural network that identifies the detection of contamination i.e. “explant is in danger” at initial stage the data was not sufficient for ml/ dl, so a simple rule-based functions was embedded to perform the tasks. after a period of six months when sufficient data was collected on cloud, the aws sagemaker was instantiated on the server side as a ai-agent to monitor the critical parameters of explants. for taking timely decisions by the ptc-experts a decision support system (dss) was incorporated to classify plants as either “healthy” or “contaminated” as shown in fig. 12. h to address the contaminated situation when the situation becomes disastrous, aimodel will indicate the alerts i.e. light intensity too low, light intensity too high, temperature too low, temperature too high, light cycle too low, light cycle too high, so that the corrective procedures can be carried out timely. in case, when there is a danger situation for the explants, the ai-agent needs to address the issue by identifying potential causes of danger that may have occurred so that the corrective procedures can be carried out. an elaboration of the ai-agent for plant in danger is shown in fig.13. fig.13. ai-model identifying potential causes of danger. “design of centralized intelligent expert system and contamination detection of tissue cultured sugarcane crop” is based on independent micro-services. to serve frontend application the visualized and summarized dashboard can be designed in any suitable interface development tool like php, asp.net or any mobile application environment as well. in this way the remote mujahid hussain memon et al. design of a centralized intelligent expert system and contamination detection of tissue cultured sugarcane crop (pp. 47 63) sukkur iba journal of emerging technologies sjet | vol. 4 no. 1 july – december 2021 57 clients (devices), ptc-experts and developers will work. the overall project structure is elaborated in fig. 14. fig. 14. cloud computing architecture based on aws-ec2 the prediction of explants inside growthroom poses many challenges for big-data analytics and secure iot infrastructure that needs an appropriate data storage and computational framework with scalable ml environment. keeping in view data storage, a traditional database (relational database) is inefficient and ineffective to manage big-data. so to achieve the performance and stability with flexible data management system with huge capacity and speed, i.e. nosql (mongodb) was implemented. additionally, hadoop data mining was used for decision and proactive analysis which has a significant role to provide services for data-mining. 4.7. descriptive to proactive approach at initial level, after the development of application first the reactive actions are taken; however, as the data gradually increase, the model would be able to perform proactively, for this the steps would be taken descriptive, diagnostic, predictive, prescriptive and finally proactive analysis. in order to train the model with version control on cloud would be required, shown in fig. 15 moreover, optionally, a trained ai-model or a simple rule-based algorithm illustrated by ptcexpert can be integrated as well, in order to provide the assistance. fig. 15. steps for aws sagemaker training & deployment of ai-model with version control. he sensors data are transformed to a dataframe for sending it via gsm-modem or through rpi-wifi depending availability. the data-frame is comprised of device-id explant-id, sensors-data and crc for checking frame integrity as shown in fig. 10. 5. experiment and results in our experiment, we used high-resolution images which were captured by our installed webcams inside growth-room where sugarcane crop was cultured. to automate the identification of ‘healthy’ and ‘contaminated’ tissue cultured plants using deep learning methods on captured pictures of explants, convolution neural networks achieved classification accuracies of 95% as shown in fig. 18. the advantage of dl method is also mujahid hussain memon et al. design of a centralized intelligent expert system and contamination detection of tissue cultured sugarcane crop (pp. 47 63) sukkur iba journal of emerging technologies sjet | vol. 4 no. 1 july – december 2021 58 being able to automatically learn the features from the input data. the dataset was divided into two sets of 70% – 30% size (3500 -1500) training – testing respectively. table 4 shows the contaminated (see fig 16) and healthy (see fig 17) for training set and testing set. fig. 16. images showing the contaminated sugarcane crop fig. 17. images showing the healthy sugarcane crop table 4: distribution of two types healthy and contaminated explant. label test set training set contaminated 1750 750 healthy 1750 750 fig. 18. graph of training and loss of trained ai model table 5: distribution of two types healthy and contaminated explant. label precision recall f1 score 0 (contaminated) 0.96 0.94 0.95 1 (healthy) 0.94 0.96 0.95 accuracy macro avg 0.95 0.95 0.95 weighted avg 0.95 0.95 0.95 in convolutional neural network feature detectors are represented as matrixes which helps to detect the relevant features in a given image. there are many filters for this process but ‘sharpen kernel’ filter makes the images sharper due to the increase in intensity of pixels as shown in fig. 19. fig. 19. showing before and after results of feature detection process step the modern generation of convolutional neural networks (cnns) has made excited results in image classification. this approach has been used to develop the detection of tissue cultured plant for recognition of contaminated and healthy growth by the use of deep convolutional neural network. the adam optimizer is used which is well in practice. we preprocessed the data by subtracting the average rgb value from our real 5000 captured images of sugarcane cultured plant is 1000px by 1000px resolution. in order to gain better comparison with advanced methods, we used the parameters of “healthy” and “contaminated” for the training-set and testing-set, which are commonly adopted. however the image size were reduced to 500px by 500px to decrease the training time. the proposed model was trained on hp z620 dual processor intel xeon e5-2640 dual hexacore processor via nvidia gtx 1660ti mujahid hussain memon et al. design of a centralized intelligent expert system and contamination detection of tissue cultured sugarcane crop (pp. 47 63) sukkur iba journal of emerging technologies sjet | vol. 4 no. 1 july – december 2021 59 4gb ddr5 gpu, which took nearly 2 hours in 250 epochs. it is implemented in keras python 3.5.6. the output of neuron is 0 or 1, the captured pictures were also cropped manually so the unnecessary objects may not come under the classification and better result be achieved. the classification after training was made and the results were achieved as shown in table 5. in order to improve the resolution of pictures, so the detection of contaminated and healthy plants could be identified truly, the generative adversarial networks (gans) was applied. the impressive performance was reported with the existing deep learning-based super resolution methods; however, the limitations were also notified to overcome this challenge. the architectural design of deep neural network models are susceptible to make small changes, where it may generate a contaminated high-resolution (hr) picture of an healthy plant or its inversely, as we have applied wide residual network architecture to improve the performance of residual network it may generate a picture with more contamination of any plant that may have a partial contamination and could survive inside the media. it is the residential block that may weakens the network as well. in order too overcome this critical situation, we have carefully studied the core problem of super resolution models where residential we have applied wide residual network [25]. to address these issues, we have worked on superresolution gans (srgan), the residual block is the building block of the residual network (resnet), which is one of the top architectures used for image recognition. in this technique we increase the width and reduce the depth of the residual network, due to decreasing the depth of the network our model reduced memory costs. however, bicubic interpolation method is also widely used as the input image, which is expensive in terms of memory and needs additional computation. significantly. to resolve the problem of over-fitting of model in the residual system, we have used extended weigh normalization. fig. 20. figure showing proposed wider residual block which has (2× to 4×) slim identity pathway channels before activation in each residual block fig. 21. architecture shows generator network consisting kernel size (k), number of feature maps (n) and stride (s) designated for each conv layer mujahid hussain memon et al. design of a centralized intelligent expert system and contamination detection of tissue cultured sugarcane crop (pp. 47 63) sukkur iba journal of emerging technologies sjet | vol. 4 no. 1 july – december 2021 60 in our experiment we have used multiple images of same direction from a dataset. to measure the peak signal to noise ratio (psnr) in rgb space, the adam optimizer was also used. the experiential results demonstrate that adam optimizer worked well; moreover, it has a great advantage over other methods like stochastic optimization. we also used a random horizontal flip and a 90-degree rotation to crop 56x56 rgb lr input images from hr images. fig.23. training l1 loss of our model trained with batch and weight normalization the proposed srgan model was trained on a 3.20 ghz cpu via the nvidia gtx1650 super gpu, which took nearly 24 hours in 250 epochs. it is implemented in keras python 3.5.6. it has been compared with the existing bicubic interpolation method. table 5: shows the results of applied srgan for image enhancement. datasets scale bicubic srgan plant tissue culture laboratory of pcsir laboratories, karachi. 2 25.17/0.8113 29.78/0.907 3 24.18/0.8029 27.57/0.8106 4 22.09/0.6888 24.96/0.8258 the goal of generator is to create images for discriminator. it just simple generate the noise from also grab pictures from real dataset. at the stage of training of discriminator, we label the fake generated images as zero and real as one. so, as time goes, the second stage of training is going to keep improving and generates the images trying to improve the quality of picture, unless the picture becomes able to be recognized in better quality than previous one. meanwhile, the picture is also compared with the real dataset, so there be no difference between false and real images. it is the beauty of gans, the generator never gets to see the actual real images, it generates convincing images only based off gradients flowing back through the discriminator. in addition to this, the discriminator improves as training phases continuing, means the generated images will also need to get better and better. fig. 22. architecture shows discriminator network consisting kernel size (k), number of feature maps (n) and stride (s) designated for each conv layer mujahid hussain memon et al. design of a centralized intelligent expert system and contamination detection of tissue cultured sugarcane crop (pp. 47 63) sukkur iba journal of emerging technologies sjet | vol. 4 no. 1 july – december 2021 61 6. conclusion the design of centralized intelligent expert system and contamination detection of tissue cultured sugarcane crop; for monitoring the production inside laboratory / growth-rooms has been presented. it monitors essential parameters such as temperature, humidity, light intensity, flammable gases and fire / smoke. in addition, 3nos. of webcams are attached for visual monitoring of explants and growth rooms. the images along with data are transmitted to the cloud services of aws, where the analytics, data mining and ai decisions are taken. this designed is intended to be installed at around 100 growth rooms in several areas of country, so that ptc-experts can monitor different growth-room across the country which would otherwise be impossible to travel and visit timely. moreover, the proposed model incorporates convolutional neural network (cnn) and generative adversarial networks (gan)” for detection of contamination and enhancement of image quality at edge device respectively, in this way gan will provide high resolution (hr) images, i.e. single image super resolution (sisr) [26] [27]. the edge device is based on raspberrypi-4 and arduino mega, making the connectivity via rpi-wifi or gsm-modem (sim900). the core purpose of system is to identify any type of contamination inside the growth-room and health of explants with detecting any disastrous situation like firesmoke or flammable gas for fire protection. the data collected at the cloud application will enable data mining, data analytics and ai which will help ptc-experts for proactive measures and future decision making to increase crop yield and quality, thus leading to coping the challenge of food scarcity and insecurity of next era. references [1] k. k. behera and s. sahoo, "rapid in vitro micro propagation of sugarcane (saccharum officinarum l. cvnayana) through callus culture," nature and science, vol. 7, no. 4, pp. 1545-0740, 2009. [2] r. h. smith, plant tissue culture: techniques and experiments, academia press of elsevier , 2013. [3] b. getnet, "review on in vitro propagation of sugarcane to," agricultural research & technology open access journal, vol. 5, no. 4, 2017. [4] c. mohan, sugarcane biotechnology: challenges and prospects, cham: springer, 2017. [5] b. d and t. t, "organization of a plant tissue culture laboratory. in: (ed.) vasil i. cell culture and somatic cell genetics of plants" in laboratory procedures and their applications, new york, acadademy press, pp. 1-12, 1984. [6] g. o. l, m. t, t. t. a and v. i.k, "plant tissue culture. in vitro cellular and fig. 24. model shows architecture of gans applied on sugarcane crop mujahid hussain memon et al. design of a centralized intelligent expert system and contamination detection of tissue cultured sugarcane crop (pp. 47 63) sukkur iba journal of emerging technologies sjet | vol. 4 no. 1 july – december 2021 62 developmental biology," physiological plant, vol. 12, pp. 473478, 2009. [7] f. jeff, p. gerald and p. raul , "comparison of sugarcane disease incidence and yield of field-run, heattreated, and tissue-culture based seedcane," journal of american society of sugar cane technologists, vol. 25, pp. 88-100, 2005 . [8] s. nandita , k. anil and k. g. girish , "genotype dependent influence of phytohormones combination and sub culturing on micro propagation of sugarcane varieties.," indian journal of biotechnology , vol. 5, no. 1, pp. 99-106, 2006. [9] j. n, n. d and s. t, "micropropagation for quality seed production in sugarcane in asia and the pacific," usa, food and agriculture organization of the united nation, pp. 13-60, 2008. [10] s. k , r. sengar and s. garg, "the effect of in vitro environmental conditions on some sugarcane varieties for micro propagation," african journal of biotechnology, vol. 10, no. 75, pp. 1712217126, 2011. [11] s. snyman, g. meyer, j. richards, s. ramgareeb and . b. huckett, "refining the application of direct embryogenesis in sugarcane: effect of the developmental phase of leaf disc explants and the timing of dna transfer on transformation efficiency," plant cell reports, vol. 25, no. 10, p. 1016–1023, 2006. [12] s. sandhu, s. gosal, k. singh, g. cheema and m. meeta , "field performance of micro propagated plants and potential of seed cane for stalk yield and quality in sugarcane.," journal of sugar technology, vol. 11, no. 1, pp. 34-38, 2009. [13] a. kuar and . s. sandhu, "high throughput in vitro micro propagation of sugarcane (saccharum officinarum l.) from spindle leaf roll segments: cost analysis for agri-business industry.," plant cell tissue organ culture, vol. 120, no. 1, pp. 339-350, 2014. [14] c. r, plant microbiology, london: edward arnold ltd, 1985 . [15] cassells and a. c, pathogen and microbial contamination management in micropropagation, netherlands: springer , 1997. [16] p. g. taherei , h. d. hossein and a. mosavi, "sugarcane growth prediction based on meteorological parameters using extreme learning machine and artificial neural network," engineering applications of computational fluid mechanics, vol. 12, no. 1, p. 738–749, 2018. [17] a. k. aman jain, "smart agriculture monitoring system using iot," international journal for research in applied science & engineering technology, 2020. [18] d. u. d. a. n. p. sobejana, "automated relative humidity and temperature control system for banana tissue culture laboratory with monitoring system and sms notification," international journal of engineering in computer science, 2019. [19] a. a. elsh`arif and s. s. abu-naser, "an expert system for diagnosing sugarcane diseases," international journal of academic engineering research, vol. 3, no. 3, pp. 19-27, 2019. [20] n. h. a. a. a. e. all., "real time monitoring critical parameters in tissue culture growth room with sms alert system," ieee international conference on intelligent systems, modeling and simulation, 2010. [21] b. a. a. e. all, "using deep learning to predict plant growth and yield in greenhouse environments," arxiv preprint arxiv:1907.00624, 2019. [22] r. n. m. t. &. m. y.-n. mohsen hesami, "development of support vector machine-based model and comparative analysis with artificial neural network for modeling the plant tissue culture procedures: effect of plant growth regulators on somatic embryogenesis of chrysanthemum, as a case study," plant methods, 2020. [23] s. p. a. e. al., "prediction of chemical composition for callus production in gyrinops walla gaetner through machine learning," information processing in agriculture, 2019. mujahid hussain memon et al. design of a centralized intelligent expert system and contamination detection of tissue cultured sugarcane crop (pp. 47 63) sukkur iba journal of emerging technologies sjet | vol. 4 no. 1 july – december 2021 63 [24] a. chlingaryan, s. sukkarieh and b. whelan, "machine learning approaches for crop yield prediction and nitrogen status estimation in precision agriculture: a review," computers and electronics in agriculture, vol. 151, pp. 61-69, 2018. [25] z. sergey and k. nikos, "wide residual networks," 23 may 2016. [online]. [26] s. zhang, g. liang and s. pan, "a fast medical image super resolution method based on deep learning network," ieee access, pp. 12319 12327, 2018. [27] y. "image super-resolution: the techniques, applications, and future," signal processing, vol. 128, p. 389–408, 2016. format template vol. 2, no. 1 | january june 2019 sjet | p-issn: 2616-7069 | e-issn: 2617-3115 | vol. 2 | no. 1 | © 2019 sukkur iba 13 iot based home automation abu bakar siddique kamboh1, sanaullah memon2 abstract: iot or the internet of things is an upcoming technology that allows us to control hardware devices through the internet. here we propose to use the iot in order to control home appliances, thus automating modern homes through the internet. the main purpose is to control any electric supply equipment load through the internet network over cloud remotely on the basic principle of the internet of things (iot). in this proposed research work, the realtime scenario the electric load can be monitored as well as configured through web-based applications. the data sent from any password protected device through a webpage. a wi-fi adapter is configured with the wireless modem to access the internet. the received internet commands are put into the wi-fi module. iot offers a wide scope of new advancements for observing and controlling, of clever structures and keen homes, by improving security to lessen vitality and support costs. with the home computerization control framework, we make our home gadgets shrewd. savvy, as in, the gadgets can be checked or perform a task as per the client's guidelines. for instance, an entryway lock framework where on the off chance that anybody obscures individual attempts to go into the house without approval, at that point the entryway, lock will initiate an alert connected to the entryway and in this we can say our house is sufficiently brilliant to give us security. keywords: internet of things (iot), cloud, ipv4, machine to machine (m2m), ospf, dhcp. 1 iict telecommunication, university of sindh, jamshoro,sindh, pakistan 2 shaheed benazir bhutto university, naushahro feroze campus,sindh, pakistan corresponding author: abubakar2k14@gmail.com 1. introduction the internet of things (iot) is a name that has been broadly perceived since the late 1990s. the iot is an arrangement of physical things that open through the internet. the term "internet of things" (iot) was first used in 1999 by british technology pioneer kevin ashton to describe a system in which objects in the physical world could be connected to the internet by sensors. the iot is highlighted as one of the most important future technology and is getting vast attention from all over the world [1]. homes of the 21st century will turn out to be increasingly more self-controlled and robotized because of the comfort it gives, particularly when utilized in a private home. a home robotization framework that enables clients to control electric apparatuses of a differing kind. the primary registering gadgets (pcs) were monsters, a room-sized mechanical assembly that took groups of individuals to configuration, handle and keep up. nowadays, they are exponentially quicker and just a variety of the extent of their ancestors. a gadget is electronic appliance that performs computations dependent on these principle segments: a processor, storage, and input & output unit. the smart thermostat runs the program by using a processor, store the programs of temperature parameters in storage and other data, and an i/o (screen, show, sound cautions, and so on). 2. background iot aims is to form a network between home appliance objects and the sensors that can save, examine, communicate and barter data together on the internet. this moves to competent industry, fabrication, efficient abu bakar siddique kamboh (et al.), web based internet of things for home automation (pp. 13 19) sukkur iba journal of emerging technologies sjet | volume 2 no. 1 january – june 2019 © sukkur iba university 14 energy management, resource management, health care management, smarter business take decisions on analyzed data, smart home automation and countless more applications. as this research paper focuses on smart home automation based on iot, the smart home concept should be understood first. smart homes combine common devices, found in homes, to be able to control it over the internet. the technology initially was designed and used to control environmental systems, but recently, almost any electrical component can be included within the system of a smart home such as doors, windows, fans, webcam, etc. [2]. wide range of articles of the iot, including items and electric devices that are not generally associated. cisco predicts that 99% of smart physical appliances will be interconnected. these items contain implanted innovation to collaborate with inward servers and the outside condition. these items are organized competently and can impart over a safe, dependable and accessible system stage. the iot is based on the associations among the electronic mechanical assembly and things. 3. aim and objectives using ipv4, ospf protocols, we aim to remotely control the appliances, which are used in the home, by using ip. we can access it through the internet all over the world. we can implement in the real world because now in the market all equipment are available which are used for home automation. home appliances are connected through wireless connection and wires. wireless is best rather than wire because of cost. in this research aims that controlling home appliances via end device using wi-fi or cellular network then the end user will directly access through a web-based interface by the web, whereas home appliances like lights, fan and door lock remotely switch [3]. iot offers a wide scope of new advancements for observing and controlling, of wise structures and keen homes, by upgrading security to lessen vitality and upkeep costs. with the home computerization control framework, we make our home gadgets shrewd. savvy as in, the gadgets can be checked or perform the task as indicated by the client's directions. for instance, an entryway lock framework where on the off chance that anybody obscure individual attempts to go into the house without approval, at that point the entryway lock will initiate a caution connected to the entryway and in this we can say our house is keen enough to give us security. the fundamental target is to interconnect all home appliances with home gateway via unguided or guided media to access the internet cloud for controlling and monitoring the home appliances by using api interface. in this research paper, we focused on home automation and use end devices like cell and computer. the iot appliances handle and control the electronic electrical and mechanical systems which are used in homes, institutes, and buildings. the appliances are connected to the cloud server and controlled by a single admin which give the permissions to several users. the admin can approach and control all the nodes connected to each end user but a single end user can control only those appliances to which the user itself is connected [4]. it performs a reality in which we can design this in the real world. we need isp to connect with the internet and we make a registration server in which every equipment which is using at home registers and we can control remotely. 4. data storage following are the data storage units: • 1 kb = (10^3) bytes • 1 mb = (10^6) bytes • 1 gb = (10^9) bytes • 1 tb = (10^12) bytes • 1 pb = (10^15) bytes • 1 eb = (10^18) bytes abu bakar siddique kamboh (et al.), web based internet of things for home automation (pp. 13 19) sukkur iba journal of emerging technologies sjet | volume 2 no. 1 january – june 2019 © sukkur iba university 15 5. management of data 5.1. structured data structured data is inserted and sustained in a file. structured data can easily be listed, categorized, reviewed, and evaluated by a computer. for example, in an office you submit employee name, address, salary, and other information to a website, you are creating structured data. structured data decrease errors and make simpler for the computer to evaluate. 5.2. unstructured data unstructured data is raw facts and figures. it does not sustain record. so, easily cannot understandable unstructured data. 6. ip addressing an ip address is a logical address which identifies the device over a computer network. the main task of the ip address are to give an identity of computers and routing of the packets on the network. 6.1. public address: a public ip address is an ip address that can be accessed over the internet. like postal address used to deliver a postal mail to your home, a public ip address is the globally unique ip address assign to an end device. 6.2. private address: a private ip address is commonly used for local area networks within a building, office, and enterprise environments. the interconnected network has different sizes. there are many small networks and a few large networks. in network to provide efficient use of ipv4 32-bit address space, the ipv4 defined several address classes and associated address formats: class a: allows 8 bits for the network portion and 24 bits for the host portion. class b: in class, b allows 16 bits for the network portion and 16 bits for the host portion. class c: in class, c allows 24 bits for network portion and 8 bits for the host portion. class d: class d is used for multicasting. and class e: class e ip address reserved for research purposes. 7. network models networking models pattern how data flows within a network. networking models include: 7.1. client server model this is the most common model used in networks. client computer request for service to the server. servers are often located maybe locally or remotely and managed by the administrator. for example, microsoft outlook is a client-server model where end users connect to the email server using a locally installed email client. 7.2. cloud computing model this is a new model where servers and services are scattered globally in distributed data centers. synchronized data across multiple servers. organizations simply subscribe to different services within the cloud. end users access applications from cloud servers without requiring an application-specific client. for instance, gmail email is a cloud service where endusers can access their email from anywhere without requiring a locally installed application. [5] 8. threats to physical safety in iot many iot devices in the home take part in so-called ‘home automation’ activities and interact with physical world components to make life ‘easier’. however, depending on the nature of the physical world interaction there could be the potential for actual physical safety threats. for example: iot smart meters & thermostats – depending on the level of integration of smart meters with the gas/electricity supply in a abu bakar siddique kamboh (et al.), web based internet of things for home automation (pp. 13 19) sukkur iba journal of emerging technologies sjet | volume 2 no. 1 january – june 2019 © sukkur iba university 16 household, remote access to these might give a hacker the opportunity to tamper with temperature levels to dangerously low or high values that could, for example, affect the health of elderly or unwell occupants, or in extreme cases start a fire or gas leak. • iot lightbulbs – remote access to these devices might allow for on/off switching which could affect the personal safety of occupants suffering from poor eyesight. • iot door lock – the ability to tamper with iot door locks could affect the safety of occupants living in dangerous neighborhoods or might be used to deliberately lock them in their homes/rooms for nefarious purposes. previous research by others has shown potential issues with such devices. 9. wireless security the difficulties in keeping a wired network secure are amplified with a wireless network. a wireless network is open to anyone within range of an access point and the appropriate credentials to associate to it. security and privacy remain a major challenge in iot [6]. the smart home aim is to enhance the level of intelligence living environment and improves human life [7]. basic wireless security includes: • setting strong authentication protocols with strong passwords • configuring administrative security • enabling encryption • changing all default settings • keeping firmware up-to-date 10. system analysis and tools fig.1 flow chart of iot based home automation 11. methodology & implementation 11.1. iot based for home automation: there are two major components isp (internet service provider) and home appliances which are connected and accessible through isp internet. abu bakar siddique kamboh (et al.), web based internet of things for home automation (pp. 13 19) sukkur iba journal of emerging technologies sjet | volume 2 no. 1 january – june 2019 © sukkur iba university 17 fig.2 iot based for home automation environment in the home, all appliances are connected & registered with central the home gateway (www.register.com) and the home gateway is connected with isp. we have reported that the very impressive implementation of the internet of things used to monitor the interconnected sensors and transmissions of data via the internet [8]. when home gateway switched "on", wi-fi signal spread in the home covered area & all home appliances can connect after the authentication process. the authentication process successfully competes then automatically ip address assigned by dhcp. if not, then try again. 12. protocols 12.1. dhcp protocol: dynamic host configuration protocol is used for assigning dynamic ip addresses to the network devices. in dhcp, a device can assign different ip, when the device connects after switched off. in many systems, the device's ip address can even change while it is still connected. dhcp also provides both static and dynamic ip addresses. in this research, we prefer to use the ospf routing protocol for routing of packets in different networks. 12.2. ospf protocol: 15.2.1. ospf packets: ospf protocol exchange the routing information packets with neighbor routers and maintain a complete map of the network. fig 3. ospf packets 15.2.2. if a neighbor is present, the ospf protocol: router establishes the neighbor adjacency and creates a routing table. 15.2.3. lsas keep the state and cost of each directly connected link. routers flood lsas to the neighbor. neighbors receiving the lsa immediately flood to other directly connected neighbors to its, until all routers in the area have lsas. 15.2.4. build the topology table based on lsas that received. this database keeps all the information about the topology of the network by using shortest path first algorithm 15.2.5. from the spf database, the best paths are selected and insert into the routing table. abu bakar siddique kamboh (et al.), web based internet of things for home automation (pp. 13 19) sukkur iba journal of emerging technologies sjet | volume 2 no. 1 january – june 2019 © sukkur iba university 18 fig 4. routing table 13. results the appliances which registered with the server can control remotely through the internet. steps are given below: • step i. access to the register server through a smartphone/end device. • step ii. open the web browser and log in with the website (www.register.com) username and password required for access to home appliances. • step iii. successfully, login into a register web server then the list of the home appliances will show in the popup menu. (see figure. 5) fig 5. registered list of home appliances • step iv. and we can switch on/off any electronic appliance by web server interface at any time anywhere. 13.1. practical: 1 carbon monoxide detector & the garage door automation • in the garage, when car switched on, the car emits the carbon monoxide gas and the sensor detects carbon monoxide when it reaches to set level (2) of carbon monoxide gas then the garage door auto opens and closes. 13.2. practical 2: • when the motion detector detects the motion inside the room, the webcam automatically switched “on” and start to record video and store it into the registered web server. (see figure. 6) abu bakar siddique kamboh (et al.), web based internet of things for home automation (pp. 13 19) sukkur iba journal of emerging technologies sjet | volume 2 no. 1 january – june 2019 © sukkur iba university 19 fig 6. after motion detection 14. conclusion the web-based internet of things for home automation has been controlled remotely through a web-based interface. the designed network system not just monitors the sensor information, but also senses the temperature, light, movements as well. for example, light switched on when the room gets dark. additionally, stores the parameters in the cloud server. this will help, the client user to analyze the state of different parameters in the home whenever anyplace. all over the world paying attention to iot, which is the third wave of it after cellular communication and the internet. in this paper, we proposed the web-based internet of things for home automation based on internet and gprs that presented the data transmission between wireless sensor networks and cellular mobile networks [9]. acknowledgment this research has been conducted at the university of sindh jamshoro. references [1] lee, i. and lee, k., 2015. the internet of things (iot): applications, investments, and challenges for enterprises. business horizons, 58(4), pp.431-440. [2] ricquebourg, d. menga, d. durand, b. marhic, l. delahoche, and c. loge.the smart home concept : our immediate future. in 2006 1st ieee international conference on e-learning in industrial electronics, pages 23–28, dec 2006. [3] pavithra, d., and ranjith balakrishnan. "iot based monitoring and control system for home automation." 2015 global conference on communication technologies (gcct). ieee, 2015. [4] dey, s., roy, a. and das, s., 2016, october. home automation using internet of thing. in 2016 ieee 7th annual ubiquitous computing, electronics & mobile communication conference (uemcon) (pp. 1-6). ieee. [5] doukas, c. and maglogiannis, i., 2012, july. bringing iot and cloud computing towards pervasive healthcare. in 2012 sixth international conference on innovative mobile and internet services in ubiquitous computing (pp. 922-926). ieee. [6] dorri, a., kanhere, s.s., jurdak, r. and gauravaram, p., 2017, march. blockchain for iot security and privacy: the case study of a smart home. in 2017 ieee international conference on pervasive computing and communications workshops (percom workshops) (pp. 618-623). ieee. [7] feng, shuo, peyman setoodeh, and simon haykin. "smart home: cognitive interactive people-centric internet of things." ieee communications magazine 55.2 (2017): 3439. [8] kelly, s.d.t., suryadevara, n.k. and mukhopadhyay, s.c., 2013. towards the implementation of iot for environmental condition monitoring in homes. ieee sensors journal, 13(10), pp.3846-3853. [9] zhu, q., wang, r., chen, q., liu, y. and qin, w., 2010, december. iot gateway: bridgingwireless sensor networks into internet of things. in 2010 ieee/ifip international conference on embedded and ubiquitous computing (pp. 347-352). ieee. vol. 1, no. 2 | july december 2018 sjet | issn: 2616-7069 | vol. 1 | no. 2 | © 2018 sukkur iba 39 a comprehensive study on reactive and proactive routing protocols under different performance metric sadaf wali1, syed irfan ullah1, a.wajid ullah khan1, abdus salam1 abstract mobile ad-hoc network (manet) has recently gained enormous studies attention because of their large potential of reliability and scalability in various fields. besides, this ad-hoc network is very flexible in nature which makes it more valuable for the researcher in the research area. ad-hoc network provides better mobility due to which it uses dynamic topology. the routing protocols possess a very important role in any manet. the routing protocols are divided into three big categories reactive protocols (on demand), proactive protocols (table-driven) and hybrid. the different routing protocols were created, which perform differently under different scenarios. this survey paper investigates the reactive and proactive routing protocol performance under different scenarios. the routing protocols like aodv, dsr, dsdv, aodv modified (r-aodv) and tora are compared under different parameters. the ns2 simulation tool is used for the simulation purpose. this paper shows the previous work done by the researchers in the field of reactive and proactive routing protocol based on its comparative analysis. our results, contrarily to previously reported studies conducted on the same routing protocols, show the superiority of reactive over proactive protocols in routing such traffic under different network scenarios and parameters. keywords: aodv, dsr, dsdv, tora, r-aodv 1. introduction a lot of work has been done in the area of routing protocols in recent time. many routing protocols have been proposed for ad-hoc community with attention on optimizing distinct aspects of the network routing. the wireless ad-hoc network is the collection of a group of mobile computers. the nodes help in packet forwarding and allow communication beyond its transmission range. a wireless ad-hoc network community is a decentralized form of wireless network which does no longer rely on a preexisting infrastructure. as wireless ad-hoc network does not require a central device or control management. therefore, it is easy to 1 department of computing and technology, abasyn university, peshawar, pakistan. corresponding email: diyaaakhan098@gmail.com establish when needed. the routers in the network are free movers in any direction. therefore, the topology is dynamic in nature. every node in the wireless ad-hoc network may act both as an end consumer node or a router and could, therefore, trade its link to different nodes often. it also enables other nodes to determine a path to another cell node and perform packet delivery that might not in the direct wireless communication. ad-hoc provides flexible and big advantages in different environment such as military, commercial and technology. the interest of the researchers is increased for the ad-hoc networks for a distributed set of applications. applications such as gaming, military applications, commercial application and sadaf wali (et-al) a comprehensive study on reactive and proactive routing protocols under different performance metric (pp. 39-51) sukkur iba journal of emerging technologies sjet | volume 1 no. 2 july – december 2018 © sukkur iba university 40 crises management services applications [1, 2]. as there is no specific device in this environment, therefore, the security challenges are the great concern for the researchers to work on it. many demanding situations that still need to be solved in such regions as addressing, routing, place control, configuration management, interoperability, security, and excessive capacity technologies [3, 4]. the routing is the procedure which is used to choose a path in a network. the main function of routing protocol is the selection of routes for multiple source destinations and its accurate delivery to the destination. in ad-hoc networking the mobile nodes are used for searching the route or paths for the connection and sharing the data. the performance of any routing protocol is the end to end delay, throughput, pdf, nrl and route acquisition time etc. 2. routing protocols the ad-hoc routing protocols are classified into three big classes 2.1. table-driven (proactive algorithms) this algorithm simply uses the tables. the data are stored and updated in these tables. examples are (dsdv), (wrp) wireless routing protocol (gsr) global state routing [4, 5]. 2.2. on demand (reactive algorithms) this algorithm creates routes on demand bases by flooding the network with route request packets. the two key procedures of source initiated on demand-driven routing protocols are the route discovery process and route maintenance process. abr, aodv, and dsr are reactive routing protocols. 2.3. hybrid protocols the composite of table driven and ondemand routing protocols which possess the attributes of both routing protocols together. zrp, cedar, and lar routing protocols belongs to hybrid protocols [6]. in section 3 the protocols that are used in ad-hoc are discussed. section 4 describes comparison evaluation of routing protocols. section 5 describes the simulation result of protocols. the last section presents the result and conclusion. fig 1. different classes of routing protocols 3. an overview of protocols 3.1. ad-hoc on-demand vector protocol (aodv) aodv is on demand protocol which creates the route on demand. the nodes move here and there very quickly which results in breaking links. the message mechanisms are having rreqs, rreps, and rerrs. route maintenance and route discovery are used by aodv whenever a sender wants to create a route its route discovery process can be done through flooding route request message. all the neighbors include in this process as they all get the route request messages. after reaching the destination route reply packet sends back on the same path used by rreq packet. each node maintains a sequence number and a routing table. the loop-free operation takes place in aodv which helps in repairing of breakage links. whenever a link breaks, the affected nodes are informed about the infected or lost link [7, 8, 9, and 10]. sadaf wali (et-al) a comprehensive study on reactive and proactive routing protocols under different performance metric (pp. 39-51) sukkur iba journal of emerging technologies sjet | volume 1 no. 2 july – december 2018 © sukkur iba university 41 3.2. dynamic source routing protocol (dsr) this protocol is designed for the multi-hop networks of moving nodes. this is an efficient routing protocol which is based on demand routing protocol which has a self-organizing network. working of this protocol can be illustrated in two steps route identification and route management. dsr guarantee loopfree routing. the source node will first check the route of the node in a cache to which it wants to send a packet. if it tries to find the route, it sends the packet. otherwise it uses route discovery. after the destination received the packet, it stores the information contained by rreqs and sends a reply back to a source node. the route mechanism is responsible for checking whether the topology changes or not. in case of breakage of a link, that route is removed from cache route and informs all nodes by sending rerrs [12, 13, and 14]. 3.3. destinationsequenced distance vector protocol (dsdv) dsdv is a table-driven based on bellmanford scheme. c. perkins and p.bhagwat developed dsdv in 1994. this algorithm helps in removing the routing loop problem. the records are recorded in a table. every node entered in a table contains a sequence number. when the connection exists the series number is even else an odd number is used. the routing records sent between nodes with smaller updates usually. every node advertises routing information using broadcasting a routing table packet updated in case of network topology changes. loop-free and count to infinity problem is much reduced in dsdv [12, 13, and 14]. 3.4. modified ad-hoc on-demand vector protocol (r-aodv) it is the new version of aodv routing protocol with some modification in aodv. the r-aodv tries to manufacture a more dependable way between the source and destination keeping route stability under consideration. the change has been done in hello and rreq messages. in r-aodv new field is embedded by hello message to record the sending time. at whatever point the (i+1)th node gets hello message sent from the ith node, it should record the hello messages arrival postpone time d_time. in route discovery stage the (i+1) th node gathers the d_time values of hello message reached within the predefined period and makes count to these. at last, the (i+1)th node appends them to the rreq packet and surges/floods the bundles to the neighbors. at the point when the rreq packet achieves the goal, the goal can choose a steady and solid route to the source as indicated by these measurements [17, 18]. 3.5. temporally ordered routing algorithm (tora) it is an on-demand routing protocol which works on the concept of path reversal of the directed a-cyclic graph (dag). tora searches multiple routes from sender to destination. tora is a loop-free and bandwidth efficient protocol that's why tora has the property to repair the route quickly during link breakage and provides multiple paths for the desired destination. it works well in networks where traffic increases gradually. tora operate in the dynamic network. it uses parameter "height" to greatly emphasize the direction of a path between the nodes. tora supports multicasting. tora can be used in conjunction with lightweight adaptive multicast algorithm (lam) to provide multicasting. the disadvantage of tora is that the algorithm may also produce temporary invalid routes as in lmr. information in a network is managed in three different ways. i. route erasure ii. route discovery iii. route maintenance the protocol is able to detect the partition and erase all invalid routes [19, 20]. sadaf wali (et-al) a comprehensive study on reactive and proactive routing protocols under different performance metric (pp. 39-51) sukkur iba journal of emerging technologies sjet | volume 1 no. 2 july – december 2018 © sukkur iba university 42 4. survey of routing protocols performance evaluation the following performance metrics are used for performance investigation of protocols. 4.1. throughput to check the total rate of transmitted packets in a unit time in the network. the nodes received by the receiver per unit time. 𝑇ℎ𝑟𝑜𝑢𝑔ℎ𝑝𝑢𝑡 = (𝑝𝑟×𝑝𝑠𝑖𝑧𝑒) 1000 [3] pr is used for the packet received and psize is the size of packets in bits. 4.2. average end -toend delay the average time used by the sender to send the packets to the receiver. all the possible delays are included in it. 𝐴𝑣𝑒𝑟𝑎𝑔𝑒 𝐷𝑒𝑙𝑎𝑦 = 𝑇𝑜𝑡𝑎𝑙 𝑑𝑒𝑙𝑎𝑦 𝐶𝑜𝑢𝑛𝑡 [3] i = packet sequence number count = total packet count delay[i] = receiving_time[i] – sending_time[i] total_delay = total delay + delay[i] 4.3. nrl the total number of packets transmitted per data packet delivered at the destination. 𝑁𝑅𝐿 = 𝑝𝑐 𝑝𝑑 [3] where pc is the total control packets and the pd is the total number of packets sent. 4.4. pdr pdr is the ratio of a successful amount of data delivered to the destination sends by the source. pdr is used to measure the efficiency of protocols 𝑃𝐷𝑅 = 𝑝𝑟 𝑝𝑠 × 100 [3] pr is used for a packet received and ps is used for a packet sent. 5. literature review on protocols 5.1. throughput in the case of low mobility the throughput of aodv is higher than comparatively to dsr and dsdv. aodv gives better throughput than r-aodv. the dsdv performance is not very strong in a high mobility within the constant value 10 to 30 percent. the performance of tora is better at high mobility but it has a lower throughput in other cases [1, 2, 3, 4, 5]. 5.2. packet delivery ratio (pdr) the packet delivery for dsr is the best among the protocols. the dsr is best in terms of average pdr. aodv is having low pdr than dsr because it drops a higher number of packets. packet loss of aodv is less than dsdv. dsdv performs worst for packet delivery. the packet loss issue is very sensitive in tora compared to other routing protocols. tora packet delivery is less than aodv. the pdr for modified-aodv is the same as aodv but changes in velocity decrease rapidly in case of aodv. [1, 2, 3, 4, 5, 19, 20]. 5.3. end-to-end delay the delay of aodv and dsr is more than dsdv. the routes are not shortest due to which aodv and dsr delay is poor. the tora protocol is also having worst delay characteristics because of the loss of distance information with progress. the average delay of r-aodv is less than aodv sadaf wali (et-al) a comprehensive study on reactive and proactive routing protocols under different performance metric (pp. 39-51) sukkur iba journal of emerging technologies sjet | volume 1 no. 2 july – december 2018 © sukkur iba university 43 5.4. normalized routing load (nrl) the nrl for aodv is highest among the other routing protocols. dsdv has the least nrl which shows that dsdv is the best routing protocol for the optimal shortest path. 6. simulation results and analysis this section explains the simulation analysis carried out for the routing protocols. according to the different author’s papers, the simulation results for the routing protocols are discussed below. 6.1. pdr (packet delivery ratio) a wajid khan [3] the result of pdr analysis for routing protocol describes that dsr works better under small network. dsr is greater than aodv. in the medium and larger network size, aodv works efficiently. its pdr is greater. the reason behind it is that as the route discovery process is very quick, it allows the aodv to adapt to the route changes quickly. ajay prakash [2] results show that while increasing pause time the pdf of aodv and dsdv is continuously decreasing for 10 numbers of a node. the results also describe that pdf of aodv is larger than dsdv. sapna s [5] according to their simulation result as the load will be less for less number of nodes dsr performs well. dsr performance slightly decreases as the number of nodes increased. dsdv performs better than the other two protocols with nodes increased. aodv also performs better but as nodes increase its performance slow down. anuj k [19] simulation result shows tora is quite sensitive to packet loss than other protocols. the pdf of aodv is slightly less than dsr. humaira nishat [18] papers compared the aodv and r-aodv. the result shows that the pdr for both the protocols is the same but with the increase of velocity, aodv ratio decreases. whereas r-aodv remains the same. this graph shows the comparison of aodv, dsr, and dsdv under the pdr parameter. it shows that aodv performance is better as the packet delivery ratio is less than the other two protocols. the other two protocols packet delivery ratio is high. fig 2: packet delivery ratio of aodv, dsdv, dsr fig 3: pdr of aodv, dsr, and dsdv sadaf wali (et-al) a comprehensive study on reactive and proactive routing protocols under different performance metric (pp. 39-51) sukkur iba journal of emerging technologies sjet | volume 1 no. 2 july – december 2018 © sukkur iba university 44 in this graph 200 numbers of nodes are used for the comparison of aodv, dsr, and dsdv. the protocols were compared under different network sizes such as small, medium and large. dsr works better under small network size while for the large and medium size network aod performs better. the graph shows that with the increase in node velocity aodv ratio decreases. the overall performance of both the protocols was the same. the graph shows that aodv has lower pdr than dsr because of a high rate of packet dropping 6.2. throughput according to the paper of a wajid khan [3], the throughput parameter is checked for aodv, dsr and dsdv routing protocols under different network scenarios like small, medium and large. the results show that the aodv protocol received more packets than the other two protocols. dsr throughput is not good in all networks. the reason behind the low performance is linked breakage. akshai aggarwal [4] paper result shows that aodv performance is better under a large number of nodes, while dsr performance is better for a small number of nodes. v. rajeshkumar [9] this paper focuses on the comparison of three routing protocols such as aodv, dsr, and dsdv. the no of nodes was (30, 40, and 50). the overall performance of aodv was higher than the other two protocols. as aodv is loop-free therefore the routing packets for it is much more. dsr performs slightly low than aodv. anuj k [19] paper describes that the overall performance of aodv is better. tora performs well for high mobility rate while for low mobility its performance was low. humaira nishat [18] the performance of both protocols was the same for the throughput but as the speed increases behind 18m/s r-aodv performance becomes low. fig 4: pdr of aodv and r-aodv fig 5: pdr of aodv, dsr, and tora sadaf wali (et-al) a comprehensive study on reactive and proactive routing protocols under different performance metric (pp. 39-51) sukkur iba journal of emerging technologies sjet | volume 1 no. 2 july – december 2018 © sukkur iba university 45 this graph represents the performance of protocols for the throughput parameter. according to this graph result, the throughput of aodv is high than other protocols. the graph shows that aodv throughput is higher than dsr and dsdv the result of the graph shows that as the speed increases r-aodv performance becomes low. both protocols result is almost the same. 6.3. end-to-end delay a wajid khan [3] the average end to end delay of dsr is better than aodv. the aodv has very high delay under all network conditions. ajay prakash [2] the graphs show that the delay of aodv is much higher than dsdv. the reason behind the end to end delay is as aodv contains the address of next hop. during link breakage, the route discovery process re-initiate which is waste of time. anuj k [19] the author compared aodv, dsr and tora protocols. according to his simulation, the end to end delay was very poor for both aodv and dsr. dsr delay was slightly higher than aodv. the end to end delay decreases as the pause time increases. similarly, tora performance was also not very good. the reconstruction of a route was also not very quick which results in lengthy delays. humaira nishat [18] the average delay of r-aodv is less than aodv. aodv gives more delay than r-aodv. fig 6:-throughput for aodv, dsr, and dsdv fig 7: average throughput of aodv, dsr, and dsdv node velocity fig 8: a throughput of aodv and r-aodv sadaf wali (et-al) a comprehensive study on reactive and proactive routing protocols under different performance metric (pp. 39-51) sukkur iba journal of emerging technologies sjet | volume 1 no. 2 july – december 2018 © sukkur iba university 46 the graph indicates the comparison of three protocols namely aodv, dsr, and dsdv. according to the result of the graph, the result of dsr is better than the other protocol. this graph compares the result for the aodv and r-aodv. the result of both the protocol shows that r-aodv performs better for the end to end delay fig 11: end to end delay of aodv, dsr and dsdv the result of the graph shows that the average end to end delay of dsr is better than aodv and dsdv this comparative analysis is based on the protocols such as aodv, dsr, and tora for the parameters end to end delay. according to the result, tora performs better than aodv and dsr. fig 9: end to end delay of aodv, dsr, and dsdv (with 10 connections) fig 12: end to end delay aodv, dsr and tora fig 10: end to end delay of aodv and r-aodv sadaf wali (et-al) a comprehensive study on reactive and proactive routing protocols under different performance metric (pp. 39-51) sukkur iba journal of emerging technologies sjet | volume 1 no. 2 july – december 2018 © sukkur iba university 47 6.4. nrl (normalized routing load) a wajid khan [3] the authors analyzed the performance of routing protocols for nrl. the result shows that aodv has low nrl in small and medium networks than dsr in a large network. amirhossein moravejosharieh[21] according to the author the dsr protocol has the best nrl than other protocols. in the value of density, dsdv has highest nrl while in speed density m-aodv has highest nrl. guntupalli lakshmikanth [22] according to their simulation result the nrl is 15 times increased in aodv and dsdv as the number of nodes increased from 40 to 100. the dsr increased 25 %. geetha jayakumar [23] according to the simulation result it shows that with the different variation of pause time dsr performs better than aodv. the nrl was low of dsr than aodv. aodv route discovery process takes more time than dsr. therefore dsr has low nrl than aodv. fig 13: nrl of aodv, dsr, dsdv this graph represents the performance of protocols for nrl which show that for both small and medium aodv has low nrl, while dsr performs better for large size. this graph is based on the performance analysis of aodv, dsr, dsdv, and tora which indicates that the dsr performs better than the other protocols. fig 14:-nrl of aodv, dsdv, dsr, and tora under low mobility case sadaf wali (et-al) a comprehensive study on reactive and proactive routing protocols under different performance metric (pp. 39-51) sukkur iba journal of emerging technologies sjet | volume 1 no. 2 july – december 2018 © sukkur iba university 48 the table indicates the average result for the following routing protocols under different parameters. the results are based upon the paper of a wajid khan [3]. the total number of nodes used in the simulation process is (50,100,150,200). the simulation time is 100 sec. packet size is 512 and interval time is 0.1. the overall performance of aodv is better for all parameters protocol property avg aodv avg dsr avg dsdv avg tora paper/author name anuj k [19] anuj k[19] anuj k[19] anuj k[19] throughput n/a n/a n/a n/a pdr 95 % 95.5 % n/a 90 % end to end delay 16 sec 17 sec n/a 14.25 sec paper/author name samir robert[24] samir robert [24] samir robert [24] samir robert [24] nrl 0.3 sec 0.1sec 3 sec 0.3 sec table i. comparative analysis of routing protocols protocol property avg aodv avg r-aodv paper/author name humaira nishat [18] humaira nishat [18] throughput 100 % 81 % pdr 88 % 86 % end to end delay 0.18 sec 0.14 sec nrl n/a n/a table ii. comparative analysis of aodv and r-aodv sadaf wali (et-al) a comprehensive study on reactive and proactive routing protocols under different performance metric (pp. 39-51) sukkur iba journal of emerging technologies sjet | volume 1 no. 2 july – december 2018 © sukkur iba university 40 this table is based on the paper of humaira nishat [18]. the comparison has been done for two protocols aodv and r-aodv. the mobile nodes are 25 with the packet size of 1500b. the performance of both the protocols is same but with the changes in the network scenarios r-aodv performs low. the table indicates the result of reactive and proactive routing protocols for different parameters. the results were taken from two papers such as anuj k [19] and samir robert [24]. the simulation parameters used in anuj k [19] are as following. the simulation time was 200 sec with the area of 500.500. cbr (udp) traffic type was used. 500 nodes are used. samir robert [24] the number of nodes used is 10. this result is for low mobility network. the packet size used is 512. 7. result and conclusion in this survey paper, a comprehensive analysis of reactive and proactive routing protocols under different performance metrics has been done. the different work of the author is also discussed on the bases of the simulation. all routing protocols show good result under specific performance metrics. the average results are shown with the help of graphs and tables of each routing protocols which explains the performance of the reactive and proactive routing protocols in detail. after comparing all the reactive and proactive routing protocols under different parameters, the overall performance of aodv routing protocol is better than the other protocols. in the case of throughput, the aodv receives more packets than the other protocols. the nrl of aodv is also lowerssss than the other protocols in different network scenarios. end to end delay and packet delivery ratio (pdr) is also medium in aodv than the other protocols. 8. future work to analyze and compare the combination of protocols such as r-aodv and tora with the other reactive and proactive routing protocols with the different parameters under the network sizes such as small, medium and large. the following parameters such as throughput, nrl, jitter, latency and collision should keep under consideration while comparing the routing protocols. table iii. comparative analysis of routing protocols protocol property avg aodv avg dsr avg dsdv paper/author name a wajid khan [3] a wajid khan [3] a wajid khan [3] throughput 55 % 45 % 45% pdr 85 % 91 % 86 % end to end delay 1.5 sec 3.0 sec 0. 2 sec nrl 2.65 sec 3.0 sec 0. 2 sec sadaf wali (et-al) a comprehensive study on reactive and proactive routing protocols under different performance metric (pp. 39-51) sukkur iba journal of emerging technologies sjet | volume 1 no. 2 july – december 2018 © sukkur iba university 40 references [1]. s.mohapatra, p.k kanungo “performance analysis of aodv, dsr, olsr, and dsdv routing protocols using ns2 simulator”, proceeded engineering 30(2012) pp 69-76. [2]. ajay prakash rai, rasvihari sharma, vineet srivastava, rashmi tikar, rinkoo bhatia.“performance comparison of aodv & dsdv ad-hoc network routing protocols on the basis of variable speed & pause time”, international journal of engineering and innovative technology (ijeit) volume 2, issue 10, april 2013 [3]. wasi ullah, haider ali, a wajid khan, arshad farhad, baseer ahmad and adnan khan, "performance assessment of reactive routing protocols in mobile ad-hoc networks under cbr traffic using ns2", ieee wispnet 2016 conference, pp 1070-1073. [4]. akshai aggarwal, savita gandhi, nirbhay chaubey." performance analysis of aodv, dsdv, and dsr in manet" international journal of distributed and parallel system (ijdps) vol.2, no.6, november 2011 [5]. sapna s. kaushik & p.r.deshmukh, "comparison of effectiveness of aodv, dsdv and dsr routing protocols in mobile adhoc networks", international journal of information technology and knowledge management july-december 2009, volume 2, no. 2, pp. 499-502. [6]. m.ilyas. “routing algorithms for balanced energy consumption in ad-hoc networks” in the handbook of ad-hoc wireless networks, 1st ed., 2003. [7]. c.e. perkins, e.m. belding-royer, and s.das. "adhoc on demand distance vector (aodv) routing protocol" rfc 3561, july 2003. [8]. i.d chakeres.and e.m.belding royer “aodv routing protocol implementation design”, ieee international conference on distributed computing systems workshop (icdcsw’04),2004. [9]. v.rajeshkumar p.sivakumar, "comparative study of aodv, dsdv, and dsr routing protocols in manet using network simulator-2", ieee international journal of advanced research in computer and communication engineering volume 2, issue 12, december 2013, pp 4564-4569 [10]. zahian ismail, rosilah hassan “performance of aodv routing protocol in mobile ad hoc network”, ieee 978-1-4244-6716-7/10/$26.00, 2010. [11]. sampo naski.”performance of ad hoc routing protocols characteristics and comparison”, helsinki university of technology telecommunications software and multimedia laboratory hut t-110.551 seminar on internetworking sjökulla, 2004. [12]. d. b. johnson and d. a. maltz. “dynamic source routing in ad-hoc wireless networks”. in imielinski and korth, editors, mobile computing, pages 153181. kluwer academic publishers, 1996. [13]. david b. johnson david a. maltz josh broch, "dsr: the dynamic source routing protocol for multi-hop wireless adhoc networks", computer science department carnegie mellon university pittsburgh, pa 15213-3891. [14]. mina vajed khiavi, shahram jamali, sajjad jahanbakhsh gudakahriz “performance comparison of aodv, dsdv, dsr and tora routing protocols in manets”, international sadaf wali (et-al) a comprehensive study on reactive and proactive routing protocols under different performance metric (pp. 39-51) sukkur iba journal of emerging technologies sjet | volume 1 no. 2 july – december 2018 © sukkur iba university 41 research journal of applied and basic sciences. vol., 3 (7), 1429-1436, 2012. [15]. afrah daas, khulood mofleh, elham jabr, sofian hamad, "comparison between aodv and dsdv routing protocols in mobile ad-hoc network (manet", ieee 978-1-4799-76263/15/$31.00, 2015 [16]. c.e. perkins and p. bhagwat, “highly dynamic destination-sequenced distance-vector (dsdv) routing for mobile computers”, acm sigcomm symposium on communications, architectures, and protocols, sep. 1994, pp. 234–244. [17]. mou zonghuna, meng xiaojing. “a modified aodv routing protocol based on route stability in manet”, [18]. humaira nishat, vamsi krishna k, "performance evaluation of on-demand routing protocol aodv and modified aodv (r-aodv) in manet" international journal of distributed and parallel systems (ijdps) vol.2, no.1, january 2011. [19]. anuj k. gupta, dr. harsh sadawarti, "performance analysis of aodv, dsr & tora routing protocols" iacsit international journal of engineering and technology, vol.2, no.2, april 2010 issn: 1793-8236. [20]. mina vajed khiavi, s shahram jamali, sajjad jahanbakhsh gudakahriz "performance comparison of aodv, dsdv, dsr and tora routing protocols in manets" international research journal of applied and basic sciences. vol., 3 (7), 1429-1436, 2012 [21]. amirhossein moravejosharieh, hero modares, rosli salleh, ehsan mostajeran "performance analysis of aodv, aomdv, dsr, dsdv routing protocols in vehicular ad-hoc network " research journal of recent sciences vol.2(7), 66-73 july (2013) [22]. guntupalli lakshmikanth, mr. a. gaiwak, "simulation-based comparative performance analysis of adhoc routing protocols". [23]. geetha jayakumar, gopinath ganapathy “performance comparison of mobilead-hoc network routing protocol” ijcsns international journal of computer science and network security, vol.7 no.11, november 2007. [24]. samir robert, rimli sengupta "comparative performance evaluation of routing protocols for mobile, ad-hoc networks". an energy efficient crypto suit for secure underwater sensor communication using genetic algorithm vol. 5, no. 1 | january – june 2022 sjet | p-issn: 2616-7069 |e-issn: 2617-3115 | vol. 5 no. 1 january – june 2022 41 assessment of rice residues as potential energy source in pakistan tarique ahmed memon1,2, mujeeb i. soomro3, khanji harijan4, sajjad bhangwar5 sabab ali shah6 abstract: pakistan produces a huge amount of biomass wastes such as rice straw (rs) and rice husk (rh), wheat straw (ws), and other biomass wastes that are being burned in the field after crop harvest to prepare the land for the next crop. biomass is known as a potential energy source that can be effectively utilized as an alternative to fossil fuels. this study aims to assess the energy potential and gaseous pollutant emissions from rice residues such as rs and rh. the energy potential of crop residues in pakistan was estimated by considering the residual characteristics such as residue to crop product ratio, moisture level and lower heating value of dry biomass obtained from the south asian countries. the mathematical models were defined for the assessment of amount of residues, available energy potential, and emissions of gaseous pollutants. the estimated amount of rice residues found to be 10147.65 thousand tons of dry biomass. the theoretical and available energy potential of the rice residues were estimated as 159219 tj, and 100,431 tj, respectively. based on dry matter fraction and proportion of crop residue burnt, the total amount of crop residue burnt for rs and rh were 1356.38 thousand tons and 307.7 thousand tons respectively. total emissions from burning of rice residues were estimated as 1749.59, 27.639, 2.432, 1.265, 4.997, and 0.549 gg for co₂, co, no, no₂, nox, and so₂, respectively. it was concluded that the crop residues generated in pakistan can be effectively utilized as an alternative energy source, to reduce electricity demand supply gap, reliance on fossils fuels, and lower contribution to global warming. keywords: rice husk; rice straw; energy potential; pollutant emissions; crop residues. 1 introduction pakistan is currently facing confronting industrial and economic challenges since couple of decades due to various factors such as energy crisis, rapid rising population, changing lifestyle of people [1][2]. among 1department of mechanical engineering, quaid-e-awam university of engineering, science, and technology (quest) campus larkana, sindh, pakistan. 2department of engineering mechanics, zhejiang university, china 310058 3department of mechanical engineering, mehran university of engineering and technology (muet) szab campus khairpur mirs, sindh, pakistan. 4 department of mechanical engineering, mehran university of engineering and technology sindh pakistan 5 department of mechanical engineering, quaid-e-awam university of engineering, science & technology pakistan. 6department of department of civil and environmental engineering, hanyang university, seoul 04763, s. korea. corresponding author: tariquememon@quest.edu.pk them, the energy crisis are caused by poor planning and mismanagement of energy sector in terms of poor market instruments, inefficient energy mix and higher transmission and distribution losses which has ultimately caused reduced employment and production of industries, and increased electricity prices [3]. mailto:tariquememon@quest.edu.pk assessment of rice residues as potential energy source in pakistan (pp. 41 53) sukkur iba journal of emerging technologies sjet | vol. 5 no. 1 january – june 2022 42 the electricity is mainly produced from conventional thermal resources sharing 58.4% followed by hydro 31%, nuclear 2.8 %, and other renewable sources 2.4% [4]. the thermal energy sources for electricity generation cannot be relied as primary energy sources due to their high prices and adverse environmental impacts [5]. fig. 1. sources contribution in electricity generation [4] utilization of fossil fuels for electricity generation has resulted greenhouse gases (ghgs) emissions into the environment [6]. the major emissions are sulphur oxides (sox), sulphur dioxide (so₂), and nitrogen oxides (nox), carbon dioxide (co₂), carbon mono oxide (co) and particulate matters (pm) [7][8]. the overall emissions in pakistan are estimated to increase in future from 557 million tons co₂ equivalent (mt co₂-eq) in 2020 to 4621 mt co₂-eq in 2050 as shown in fig. 2 [9]. the trend of utilizing biomass as a potential source has been increasing throughout the world because of certain advantages such as abundant availability, lower environmental impacts through modern biomass conversion technologies, increased energy security and supply, development of rural areas and job opportunities. biomass is more economical in comparison with other renewable energy sources because of less capital and investment cost per unit of production [10]. pakistan is still inefficient to implement advanced technologies for efficient utilization of alternative renewable energy resources. however, some of the renewable energy projects are installed such as biomass [11], solar [12], wind [13]. the different energy sources and their conversion routes are presented in the fig. 2 [14]. pakistan is an agrarian country in which the contribution of agriculture sector in country’s gross domestic product (gdp) is 21%. the major crops are rice, sugarcane, wheat, cotton, and maize producing waste in the form of straw and husk, bagasse, wheat straw (ws), cotton straw and corn stover respectively [4]. fig. 2. classification of energy resources [14] pakistan is an agrarian country in which the contribution of agriculture sector in country’s gross domestic product (gdp) is 21%. the major crops are rice, sugarcane, wheat, cotton and maize producing waste in the form of straw and husk, bagasse, wheat straw (ws), cotton straw and corn stover respectively [4]. rice is considered as one of the most commonly produced and consumed grains in the world population. it is known as prominent staple food in many countries as it is rich in proteins, lipids, carbohydrates, phytic and phenolic acids, minerals, vitamins b and e [16]. agricultural residues are produced from harvesting and processing of crops and are categorized as primary and secondary residues. primary residues such as rs, ws, and sugar cane tops are those residues which 31% 58.4 % 2.4% 2.8% hydroelectric thermal renewable nuclear assessment of rice residues as potential energy source in pakistan (pp. 41 53) sukkur iba journal of emerging technologies sjet | vol. 5 no. 1 january – june 2022 43 are produced in the field when harvesting the crop, while secondary residues such as rice husk (rh), wheat husk (wh) and bagasse are produced at processing mills. primary residues have lower availability because of difficulty in the collection, and farmers utilize as fertilizer, animal feed. availability of secondary residues is comparatively high at the processing mills with little handling and transportation cost [18]. being an agrarian country, pakistan produces massive quantity of crop residues like stems, leaves, and seed pots that can be efficiently utilized as energy source. huge amount of crop residues such as rs, rh, ws, sunflower stems, garden biomass wastes, dates, mangoes, and orange tree biomass are burned in the field after crop harvest every year to prepare the land for next crop [19]. the amount of crop residue directly depends upon the crop production. the amount of crop residue generated directly depends upon the yield of crop. rice crop has two main types of residues, the field residues such as rs and the process residues such as rh and bran. rs is dry stalks of cereal plants collected at the time of harvest in the field. rh is outer most layer of rice grain and is known as process residue. rice bran is used as cattle, poultry and fish food [20][21]. rs is used as feedstock and bedding material for livestock, domestic fuel as well as building material in rural areas [22]. the burning of crop residues is a common activity in developing countries because of unawareness of benefits related to its alternative uses as an energy source [23][24]. crop and agricultural residues are being used as domestic fuels for heating and cooking purpose since ancient times. almost half of the people in the world especially in developing countries are utilizing the agricultural and crop residues as a primary energy source and are known as fourth major energy source after coal, gas and oil [25]. after harvesting rice crop, the farmers usually burn residues because they believe that it has advantageous effects on crop yields [26][27]. many studies proposed that burning rice residues have positive as well as negative effects on the soil quality. burning increases the availability of phosphorous and potassium nutrients for short time [28]. according to [29] burning rice residues in the field enhance the crop productivity for the next crop season. some researchers have found negative effects of residues burning such as [30] and [31], according to them burning causes loss of plant nutrients such as nitrogen, potash and sulphur and microbial population and organic carbon is reduced. on the other hand, some practices alternative to burning of crop residues such as (1) recycling of residue in the soil through incorporation, surface retention to improve soil’s physio-chemical and biological properties [32]. (2) animal feed [36], (3) mushroom cultivation or bioenergy production [34]. (4) for cooking and lighting purpose [35]. burning rs has many negative impacts, producing smoke, gaseous and particulate emissions (pm 10, pm 2.5, nox, so₂) in the atmosphere which ultimately affects health of population and climate [36][37]. fig. 3. open field burning of rice straw [38] fig. 4. rice husk used in brick manufacturing industries [40] rh is supplied to brick manufacturing industries where it is being burned, which causes release of co₂ and methane into assessment of rice residues as potential energy source in pakistan (pp. 41 53) sukkur iba journal of emerging technologies sjet | vol. 5 no. 1 january – june 2022 44 atmosphere which takes part in greenhouse effect and poor air quality. the amount of co₂ released from burning depends upon the amount of rh burned and its carbon fraction [39]. the burning of rice residues has also adverse environmental impacts in terms of air pollution and climate change. incomplete combustion of agricultural residues produces emissions of toxic air pollutants and greenhouse gases, black carbon which is a second largest source of global warming contribution after carbon dioxide. it captures radiations and warms the atmosphere and ultimately enhances glacier melting [26][41][24]. rh generated in the mill is partly used for heating purposes. surplus amount of rh is supplied to brick manufacturing industries. rh is also agricultural waste generated after paddy rice milling. it is often used as fuel for green technology. rh is used in boilers to produce steams, in brick kilns to fire clay bricks, in boilers for rice processing industry, where rh have gone through self-burning process [42]. limited studies have been conducted in pakistan for the estimation of rice residues without taken into account the variation of residual characteristics such as residue to crop product ratio, lower heating values, availability factor and relative moisture content. there have been many studies related to the utilization of rice residues as energy source. [1] estimated that 17.86 million tons of rs from the rice crop are produced. [43] concluded that rh based electricity generation is more economically and environmentally viable compared to coal-based electricity generation. [44] estimated that rs and husk generated in the punjab province of india contributed 33.43% of total residue potential. [45] have estimated that bangladesh produces enormous amount of rice residues such as rs and husk. the available energy potential from rice residues was estimated to be 425.324 pj during the year 2015-16. [39] estimated that annually 1328 gwh electricity can be generated from the available quantity of rh in pakistan and 36,042 tons of co₂ equivalent (tco₂-eq) per year of methane can be avoided by utilizing rh instead of conventional fossil fuels. [46] have studied biomass residues as potential energy source of electricity generation in punjab province of pakistan. it is concluded that lot of potential is available to generate electricity of 1700 mw. [47] studied that the open field burning of rs release co₂ and methane which contributes global warming. they have concluded that rs can be utilized for electricity generation through efficient conversion technologies. [48] have estimated that total residue potential from arable field crops and horticulture crops were 59.432 million tons, and 15.652 million tons, respectively. the available energy potential from arable field crops was 298,955 tj and from horticultural crops was 65,491 tj. [49] studied the resource potential of agricultural and animals waste for the generation of electricity and greenhouse gases mitigation potential. it was estimated that annual potential of 62,808 gwh from the total waste can be generated which accounts 27% of the total electricity consumption in the country. moreover, the mitigation of greenhouse gases emissions from the biomass wasted based electricity generation were about 4,096 thousand t co₂ per year. [50] studied agricultural crop residues as renewable energy source in pakistan. a model based on matlab was developed to estimate the existing and future accessibility of the selected biomass residues as an energy source. they have estimated that 11000 mw electricity can be produced from the selected crop residues. forecast shows that the plant capacity can be increased up to 16,000 mw by the year 2035. [51] studied the availability of rh for the generation of electricity in bangladesh. they have proposed that rh is a viable option for the electricity generation in the country. [52] conducted experimental work on the open field burning of rs. they have found that the percentage of co₂, co, and nox to the total emissions were 15.3%, 13.9%, and 31.4% respectively. the purpose of this study was to assess the potential of rice residues as an energy source assessment of rice residues as potential energy source in pakistan (pp. 41 53) sukkur iba journal of emerging technologies sjet | vol. 5 no. 1 january – june 2022 45 and to estimate the gaseous pollutant emissions like co, co₂, no, no₂, nox, and so₂ caused by open field burning of rice residues. in this study we have estimated the potential of rice residues as dry mass, theoretical and available energy potential by taking into account the residual characteristics from the previous studies conducted in south asian countries such as pakistan, india, bangladesh, sri lanka, and afghanistan and limit values have been estimated. 2 methodology in order to estimate the residue potential, the first stage is to get primary input data relevant to rice crop production for the estimation of amount of available residue and energy potential from the crop residues. in the next step, biomass crop residues such as rs and rh is estimated from the annual crop production by considering residue to crop product ratio (rpr) and moisture level (m). fig. 5. flow diagram for assessing the energy and emissions reduction potential from rice residues the energy potential from the crop residue can be estimated by considering energy content value and availability factor of the particular residue. the amount of emissions from open field burning of residues is estimated by considering open field burning of the particular residue, emissions factors of particular gaseous pollutants and dry matter content. the methodology flow diagram is presented in the fig. 5. 2.1 rice crop production according to pakistan economic survey report 2020, rice crop area was increased by 8% to 3.034 million hectares during 2019-20, therefore, the production increased by 2.9% to assessment of rice residues as potential energy source in pakistan (pp. 41 53) sukkur iba journal of emerging technologies sjet | vol. 5 no. 1 january – june 2022 46 7.410 million tons compared to previous year 2018-19. paddy rice production data in pakistan from 2012-13 to 2019-20 is taken from pakistan economic survey reports [4][54] and is presented in table 1. table i. paddy rice production in pakistan [4] year potential of paddy (thousand tons) 2012-13 5536 2013-14 6798 2014-15 7003 2015-16 6801 2016-17 6849 2017-18 7450 2018-19 7202 2019-20 7410 average 6881 for the estimation of energy potential and gaseous pollutant emissions, the average value of the crop production was 6881 thousand tons which is considered as input data in order to reduce the yearly crop yield fluctuations. 2.2 characterization of rice crop residues the evaluation of biomass characteristics is an important step for the assessment of energy potential through the conversion process prior to it utilization. the properties of biomass change rapidly with certain factors such as climatic conditions and seasonal variations which affect the thermal decomposition behavior, the product yield and quality [55]. literature shows that there is considerable difference in characteristics and quantity of the crop residues depends upon many factors such as local climate conditions, difference in agricultural practices, crop production, crop type and varies from region to region [46][48][50][56]. hence, the residual characteristics of biomass vary region to region. in this study, residual characteristics like residue crop production ratio (rpr), moisture level (m) and lower heating value (lhv) of dry biomass residues were taken into account from different studies in south asian countries such as pakistan, india, bangladesh, sri lanka, and afghanistan. the average values of residual properties were considered in order to reduce fluctuations in the data and results. the energy potential of rice residues was estimated by considering rpr, m, and lhv of dry matter of residues. moisture level plays a pivotal role in selection of biomass to energy conversion process [57]. m content indicates the presence of water in biomass and is an important factor for conversion of biomass feedstock to energy. high m decreases the heating value of the feedstock due to mass of water [19]. therefore, the energy intensive drying process is required to reduce the m according to the conversion technology [58]. residual characteristics values of rice straw and husk are presented in table 3 and 4 respectively. it can be observed in the table 3 and 4 that amount of residues generated from the crop production varies from region to region. for example, from table 3, residue to crop ratio of rs ranges from 1 to 1.76 in different countries. the rpr of rice straw in pakistan was given as 1. 1.5, 1.54, and 1.757. but these values were different for bangladesh as 1.695 and 1.76. for india and afghansitan it was close to pakistan that is 1.5, for sri lanka it was 1.76. moisture content values of rice straw in these countries were near to each other and varies from 7.43 to 12.7%. however lower heating values of moisture varied from 12.81 to 18.74 mj/kg. there were, 13.8, 17, and 18.74 mj/kg for pakistan. for india it was 15.03 and 15.54 mj/kg, for afghanistan it was 12.81 mj/kg, for sri lanka, it was 16 mj/kg, and for bangladesh it was 16.3 mj/kg. table ii. elemental analysis of rice residues [39][56] composition (%) rice straw (rs) rice husk (rh) carbon 28.55 44.13 hydrogen 3.98 5.01 nitrogen 1.15 0.39 sulphur 0.61 0.07 oxygen 65.71 50.40 assessment of rice residues as potential energy source in pakistan (pp. 41 53) sukkur iba journal of emerging technologies sjet | vol. 5 no. 1 january – june 2022 47 table iii. characteristics of rice straw characteristics rice straw country reference residue crop ratio, (rpr) (11.76) pakistan-[18][50] [46][59][60][61] india-[62][44][22] afghanistan[20] [63]. sri lanka-[64] bangladesh-[21] [45][65]. lower heating value, (lhv) (mj/kg) (12.8118.74) pakistan [50] [46] [60] [56]. india[66] [62][44]. afghanistan-[20]. sri lanka-[64]. bangladesh[21] [45]. moisture content, (m) (%) (7.4312.7) pakistan-[59] [56]. afghanistan-[20]. sri lanka-[64]. bangladesh-[21]. india-[66]. 2.3 theoretical residues potential theoretical rice residues (rh and rs) potential indicates the amount of residue j generated per year from the rice crop production. the amount of residues generated depends upon annual crop production, ratio of residue to crop product (rpr), and moisture level (m). theoretical amount of residue j is estimated from the equation (1) by taking relevant data from table 3, and 4. 𝑇𝑅𝑃𝑗 = cp × 𝑅𝑃𝑅𝑗 × [ 100−𝑀𝑗 100 ] (1) where, cp is the annual amount of the crop production in thousand tons, rpr is the residue j to crop production ratio. thus, rpr=1 indicates that, 1 ton of the crop residue is produced from the 1 tons of crop production. m indicates the relative moisture content (%) of residue j. amount of residue generated depends upon the crop varieties, environmental factors region and agricultural practices of the concerned region. for example, rpr becomes 1.75 when the rice crop is harvested at 5cm above the ground level. rpr could decrease to 0.45, if the crop is cut by more than 5 cm above the ground [28][44]. the eight years average data related to the rice crop production from 2012-13 to 2019-20 is taken from pakistan economic survey reports in 2018-19 and 2019-20 in order to reduce crop yield fluctuations per year. table iv. characteristics of rice husk characteristic s rice husk country reference residue crop ratio, (rpr) (0.20 0.321) pakistan[18][50] [46][59][60][61][39 ] india-[62][44][22] afghanistan [20][63]. sri lanka-[64] bangladesh [21][45] [65]. lower heating value, (lhv) (mj/kg) (13.48 -17) pakistan [50] [46] [60] [56]. india-[66] [62] [44]. afghanistan-[20]. sri lanka-[64]. bangladesh[45]. moisture content, (m) (%) (7.8812.4) pakistan-[59] [56] [39]. afghanistan-[20]. sri lanka-[64]. bangladesh-[21]. india-[66]. 2.4 theoretical energy potential the theoretical or ideal energy potential represents the total amount of energy potential from the generated dry biomass residues and can be estimated by the following equation (2). 𝑇𝐸𝑃𝑗 = 𝑇𝑅𝑃𝑗 × 𝐿𝐻𝑉𝑗 (2) where, lhv indicates lower heating value (mj/kg) of particular residue j 2.5 available energy potential the available energy potential indicates the amount of energy that can be technically and economically generated from the crop assessment of rice residues as potential energy source in pakistan (pp. 41 53) sukkur iba journal of emerging technologies sjet | vol. 5 no. 1 january – june 2022 48 residues. its value depends upon certain factors such as collection mechanism, characteristics of biomass and the conversion technology [44]. the theoretical energy potential is constraints by alternative uses of crop residues and agricultural practices of particular region [44]. therefore, availability factor is incorporated in the following equation to estimate the available energy potential from the crop residues. 𝐴𝐸𝑃𝑗 = 𝑇𝐸𝑃𝑗 × 𝐴𝑗 (3) where a is the availability of the residue j, which is 0.6 for rs and 0.8 for rh [45]. table v. residue product ratio, lhv, and moisture, of rice crop residues. 2.6 estimation of total annual gases emissions in order investigate/estimate the amount of gaseous emissions such as (co, co₂, no, no₂, nox, and so₂) caused by open field burning of rice rs and rh. the total amount of gaseous pollutant emissions can be estimated by the following eq. (4). 𝐸𝑖,𝑗 = 𝐶𝑗 × 𝐸𝐹𝑖,𝑗 (4) where, e is total annual emissions (gg) from the pollutant i emitted from the crop residue j. ef is the specific emission factor (g/kg) of pollutant i from burning of the residue j, and c is the total amount (kg) of burnt crop residue j. 2.6.1 estimation of crop residues burnt the crop residues burned in the field depends upon the amount of crop production, dry matter content, portion of the residue burned. the total amount of the crop residue burnt can be estimated by the following eq. (5). 𝐶𝑗 = 𝐶𝑝 × 𝑅𝑃𝑅𝑗 × 𝐷𝑗 × ∅𝑗 (5) where, trp is theoretical biomass potential (thousand tons) of the residue j, ∅ is crop residue j burnt (%) and d is dry matter content of residue j. dry matter content for rh and straw is taken from [67] and proportion of burnt residue (%) is taken as 25% as estimated by [68]. 2.6.2 emission factors emission factors are used to estimate and quantify the pollutant emissions from burning of biomass residues vary with time, space and largely depend upon type, quality and biomass fuel composition and climate and burning condition and onsite experiments such as indoor and in-field [69][24]. the mean values of emission factors of different gaseous pollutants from the open field burning of rice residues as estimated by [24] have presented in the table 6. table vi. emissions factors (ef) (g/kg) for gaseous pollutants [24]. rice residues rice straw rice husk co₂ 1090.1 880.48 co 17.19 14.05 no 1.48 1.38 no₂ 0.89 0.19 nox 3.16 2.31 so₂ 0.38 0.11 3 results and discussion the theoretical crop residues potential from rs and rh, the theoretical and available energy potential and total emissions of gaseous pollutants is estimated from rs and rh. 3.1 total amount of residues and energy potential the mean value eight years from 2012 to 2020 of rice crop production is taken as 6881 thousand tons in order to reduce yearly crop yield fluctuations. the total amount of rice residues obtained as dry substance and is estimated as 10,147.65 thousand tons. the amount of rs produced is 8,540 thousand tons rice straw rice husk range mean range mean rpr 1-1.76 1.38 0.20 0.321 0.26 m (%) 7.4312.7 10.065 7.8812.4 10.14 lhv) (mj/kg) 12.8118.74 15.775 13.4817 15.24 assessment of rice residues as potential energy source in pakistan (pp. 41 53) sukkur iba journal of emerging technologies sjet | vol. 5 no. 1 january – june 2022 49 while the amount of rh generated is 1607.65 thousand tons of dry mass. theoretical energy potential was estimated as 159,219 tj out of which 134,718.5 tj was estimated from rs and 24,500.586 tj from rh. the limit values of rice crop residues characteristics were considered, and maximum, minimum and average potential values were estimated as presented in table 5. the residual properties of rice residues (residue crop ratio, lower heating value, and relative moisture content) values vary among the countries as shown in table 3 and 4. therefore, the estimated potential values from crop residues change within the limits. the location of the crop and its characteristics such as crop production and agricultural practices also affect the quantity of residues generated. as shown in fig. 6, when estimating the energy potential of rs, the energy potential of 81,600 tj was obtained when the minimum values of properties such as ratio of residue to product, moisture level, and lower heating values were taken. similarly, energy values of 134,718.5 tj and 198,129 tj from rs were obtained when average and maximum limit values were considered respectively. fig. 6. comparison of tep of rice residues fig. 7 shows total theoretical and available estimated potential from the crop residues in pakistan. potential values were estimated as minimum, maximum and average of residual characteristics. the total theoretical energy potential of the rice residues obtained from the rice crop production has minimum 98,692.64 tj, an average 159,219 tj, and maximum of 231,024 tj. while the total available energy potential obtained from the rice residues were estimated as minimum 62,634 tj, an average 100,431 tj, and maximum value of 145,193 tj. fig. 7. total theoretical and available energy potential of rice residues 3.2 estimation of gaseous emissions the amount of gaseous pollutants such as co, co₂, no, no₂, nox, and so₂ emissions (gg) from the rice residues open field burning are estimated by considering the proportion of residue burn, dry matter content, and specific emission factors of gaseous pollutants. based on dry matter fraction and proportion of burnt crop residue, the total amount of burnt crop residue for rs and rh was 2017.85 thousand tons and 380 thousand tons respectively as presented in the table 7. the amount of crop residue such as rs burnt is more than the rh. because the yield value of rs is more. table vii. amount of burnt residues in pakistan rice residues rice straw rice husk rpr 1.38 0.26 amount of crop residue (th. tons) 9495.78 1789 dry matter content [70] 0.85 0.85 assessment of rice residues as potential energy source in pakistan (pp. 41 53) sukkur iba journal of emerging technologies sjet | vol. 5 no. 1 january – june 2022 50 crop residue/dry matter burnt (%) [68] 25 25 amount of burnt residue, 𝐶𝑗 (th. tons) 2017.85 380 total amount of pollutant emissions (gg) from rice residues for co₂, co, no₂, no, nox, and so₂ are presented in fig. 10. total pollutant emissions from rice residues were 2534.58, 40.025, 3.51, 1.868, 7.254, and 0.808 gg for co₂, co, no, no₂, nox, and so₂ respectively. total pollutant emissions from burning of rs were 2200 gg for co₂, 34.686 gg for co, 2.986 gg for no, 1.796 gg for no₂, 6.376 gg for nox, and 0.766 gg for so₂. it can be observed from the fig. 8 that the gaseous pollutants emissions from the burning of rs is more than the rh because of emissions factors of rs is higher than rice husk. fig. 8. emissions from rice straw and rice husk 4 conclusion this study focuses on the exploitation of rice crop residues as an energy source and assessment of gaseous pollutants emissions caused by open field burning. the average amount of rice residues is estimated to be 10147.65 thousand tons that can be efficiently utilized to produce 159219 tj of energy which is approximately 3803 kilo tons of oil equivalent (ktoe). if this amount of residues is properly utilized for electricity generation, 44,229 gwh can be produced annually. the available energy potential is estimated as 100,431tj. this available energy potential is 2398.75 ktoe. if the available amount of residues is efficiently utilized for electricity generation, an annual amount of 27,897gwh electricity could be produced. total emissions from burning of rice residues were 1749.59, 27.639, 2.432, 1.265, 4.997, and 0.549 gg for co₂, co, no, no₂, nox, and so₂ respectively. hence it is concluded that the crop residues generated in pakistan can be effectively utilized as an alternative energy source, to reduce the demand supply gap, reduce reliance on fossil fuels and prevent environmental degradation. 5 recommendations there are certain issues related to utilization of crop residues as an energy source such as residues availability, agricultural practices, and unawareness about the efficient utilization of residues as alternative source of energy. therefore, the government of pakistan should institute and implement proper policies and regulations among the public and private sectors to encourage renewable energy technologies by providing subsidies, incentives and reducing taxes, and creating awareness among the farmers about the utilization of crop residues as an alternative energy source. references [1] m. irfan et al., “assessing the energy dynamics of pakistan: prospects of biomass energy,” energy reports, vol. 6, pp. 80–93, 2020, doi: 10.1016/j.egyr.2019.11.161. [2] k. r. abbasi, m. shahbaz, z. jiao, and m. tufail, “how energy consumption, industrial growth, urbanization, and co2 emissions affect economic growth in pakistan? a novel dynamic ardl simulations approach,” energy, vol. 221, p. 119793, 2021, doi: 10.1016/j.energy.2021.119793. [3] m. o. chaudhry, m. z. faridi, and s. riaz, “energy crisis and macroeconomic stability in pakistan.,” pakistan j. soc. sci., vol. 35, no. 1, pp. 425–436, 2015. assessment of rice residues as potential energy source in pakistan (pp. 41 53) sukkur iba journal of emerging technologies sjet | vol. 5 no. 1 january – june 2022 51 [4] g. of p. finance division, pakistan economic survey report 2019-20. . [5] t. iqbal et al., “sketching pakistan’s energy dynamics: prospects of biomass energy,” j. renew. sustain. energy, vol. 10, no. 2, 2018, doi: 10.1063/1.5010393. [6] n. hossain, m. a. bhuiyan, b. k. pramanik, s. nizamuddin, and g. griffin, “waste materials for wastewater treatment and waste adsorbents for biofuel and cement supplement applications: a critical review,” j. clean. prod., vol. 255, 2020, doi: 10.1016/j.jclepro.2020.120261. [7] k. harijan, m. a. uqaili, m. memon, and u. k. mirza, “forecasting the diffusion of wind power in pakistan,” energy, vol. 36, no. 10, pp. 6068–6073, 2011, doi: 10.1016/j.energy.2011.08.009. [8] h. zhang et al., “a laboratory study of agricultural crop residue combustion in china: emission factors and emission inventory,” atmos. environ., vol. 42, no. 36, pp. 8432–8441, 2008, doi: 10.1016/j.atmosenv.2008.08.015. [9] n. abas, a. kalair, n. khan, and a. r. kalair, “review of ghg emissions in pakistan compared to saarc countries,” renew. sustain. energy rev., vol. 80, no. january 2016, pp. 990–1016, 2017, doi: 10.1016/j.rser.2017.04.022. [10] m. m. rahman and j. v. paatero, “a methodological approach for assessing potential of sustainable agricultural residues for electricity generation: south asian perspective,” biomass and bioenergy, vol. 47, no. 0, pp. 153–163, 2012, doi: 10.1016/j.biombioe.2012.09.046. [11] n. a. khan and h. el dessouky, “prospect of biodiesel in pakistan,” renew. sustain. energy rev., vol. 13, no. 6–7, pp. 1576–1583, 2009, doi: 10.1016/j.rser.2008.09.016. [12] m. m. rafique and h. m. s. bahaidarah, “thermoeconomic and environmental feasibility of a solar power plant as a renewable and green source of electrification,” int. j. green energy, vol. 16, no. 15, pp. 1577–1590, 2019, doi: 10.1080/15435075.2019.1677237. [13] h. yaqoob et al., “feasibility study of a 50 mw wind farm project in pakistan,” j. adv. res. fluid mech. therm. sci., vol. 74, no. 2, pp. 27–42, 2020, doi: 10.37934/arfmts.74.2.2742. [14] h. yaqoob et al., “case studies in chemical and environmental engineering energy evaluation and environmental impact assessment of transportation fuels in pakistan,” case stud. chem. environ. eng., vol. 3, no. december 2020, p. 100081, 2021, doi: 10.1016/j.cscee.2021.100081. [15] g. of p. finance division, pakistan economic survey 2017-18. 2019. [16] l. a. silva, i. f. s. dos santos, g. de o. machado, g. l. tiago filho, and r. m. barros, “rice husk energy production in brazil: an economic and energy extensive analysis,” j. clean. prod., vol. 290, p. 125188, 2020, doi: 10.1016/j.jclepro.2020.125188. [17] k. ahmed, s. shahid, and n. nawaz, “impacts of climate variability and change on seasonal drought characteristics of pakistan,” atmos. res., vol. 214, no. august, pp. 364–374, 2018, doi: 10.1016/j.atmosres.2018.08.020. [18] a. w. bhutto, a. a. bazmi, and g. zahedi, “greener energy: issues and challenges for pakistan biomass energy prospective,” renew. sustain. energy rev., vol. 15, no. 6, pp. 3207–3219, 2011, doi: 10.1016/j.rser.2011.04.015. [19] a. abdullah et al., “bioenergy potential and thermochemical characterization of lignocellulosic biomass residues available in pakistan,” vol. 37, no. 2, pp. 1–8, 2020, doi: 10.1007/s11814-020-0624-0. [20] a. g. noori, p. a. salam, and a. m. fazli, “assessment of selected biomass energy potential in afghanistan,” vol. 4, no. 6, pp. 6–14, 2019. [21] a. s. n. huda, s. mekhilef, and a. ahsan, “biomass energy in bangladesh : current status and prospects,” renew. sustain. energy rev., vol. 30, pp. 504–517, 2014, doi: 10.1016/j.rser.2013.10.028. [22] m. hiloidhari and d. c. baruah, “rice straw residue biomass potential for decentralized electricity generation: a gis based study in lakhimpur district of assam, india,” energy sustain. dev., vol. 15, no. 3, pp. 214–222, 2011, doi: 10.1016/j.esd.2011.05.004. [23] r. azhar, m. zeeshan, and k. fatima, “crop residue open fi eld burning in pakistan ; multi-year high spatial resolution emission inventory for 2000 – 2014,” atmos. environ., vol. 208, no. september 2018, pp. 20–33, 2019, doi: 10.1016/j.atmosenv.2019.03.031. [24] m. irfan et al., “estimation and characterization of gaseous pollutant emissions from agricultural crop residue combustion in industrial and household sectors of pakistan,” atmos. environ., vol. 84, pp. 189–197, 2014, doi: 10.1016/j.atmosenv.2013.11.046. [25] g. cao, x. zhang, s. gong, and f. zheng, “investigation on emission factors of particulate matter and gaseous pollutants from crop residue burning,” j. environ. sci., vol. 20, no. 1, pp. 50–55, 2008, doi: 10.1016/s1001-0742(08)60007-8. [26] t. ahmed, b. ahmad, and w. ahmad, “why do farmers burn rice residue? examining farmers’ choices in punjab, pakistan,” land use policy, vol. 47, pp. 448–458, 2015, doi: 10.1016/j.landusepol.2015.05.004. [27] a. junpen, j. pansuk, o. kamnoet, and p. cheewaphongphan, “emission of air pollutants from rice residue open,” 2018, doi: 10.3390/atmos9110449. [28] o. erenstein, “crop residue mulching in tropical and semi-tropical countries: an evaluation of residue availability and other technological assessment of rice residues as potential energy source in pakistan (pp. 41 53) sukkur iba journal of emerging technologies sjet | vol. 5 no. 1 january – june 2022 52 implications,” soil tillage res., vol. 67, no. 2, pp. 115–133, 2002, doi: 10.1016/s01671987(02)00062-4. [29] m. haider, published by the south asian network for development and environmental economics (sandee) po box 8975, epc 1056, kathmandu, nepal. tel: 977-1-, no. 71. 2012. [30] p. k. gupta et al., “residue burning in rice-wheat cropping system: causes and implications,” curr. sci., vol. 87, no. 12, pp. 1713–1717, 2004. [31] b. j. heard, c. cavers, and g. adrian, “up in smoke—nutrient loss with straw burning,” better crop., vol. 90, no. 3, pp. 10–11, 2006. [32] k. g. mandal, a. k. misra, k. m. hati, k. k. bandyopadhyay, and p. k. ghosh, “rice residue management options and effects on soil properties and crop productivity,” vol. 2, no. january, pp. 224– 231, 2004. [33] r. article, s. devi, c. gupta, s. l. jat, and m. s. parmar, “crop residue recycling for economic and environmental sustainability : the case of india,” pp. 486–494, 2017. [34] c. román-figueroa, n. montenegro, and m. paneque, “bioenergy potential from crop residue biomass in araucania region of chile,” renew. energy, vol. 102, pp. 170–177, 2017, doi: 10.1016/j.renene.2016.10.013. [35] a. vatsanidou, c. kavalaris, s. fountas, n. katsoulas, and t. gemtos, “a life cycle assessment of biomass production from energy crops in crop rotation using different tillage system,” sustain., vol. 12, no. 17, 2020, doi: 10.3390/su12176978. [36] i. kumar, v. bandaru, s. yampracha, l. sun, and b. fungtammasan, “limiting rice and sugarcane residue burning in thailand: current status, challenges and strategies,” j. environ. manage., vol. 276, no. january, p. 111228, 2020, doi: 10.1016/j.jenvman.2020.111228. [37] m. z. haider, “determinants of rice residue burning in the field,” j. environ. manage., vol. 128, pp. 15– 21, 2013, doi: 10.1016/j.jenvman.2013.04.046. [38] c. menke, s. garivait, and b. gadde, “air pollutant emissions from rice straw open field burning in india , thailand and the philippines,” environ. pollut., vol. 157, no. 5, pp. 1554–1558, 2009, doi: 10.1016/j.envpol.2009.01.004. [39] o. mohiuddin, a. mohiuddin, m. obaidullah, h. ahmed, and s. asumadu-sarkodie, “electricity production potential and social benefits from rice husk, a case study in pakistan,” cogent eng., vol. 3, no. 1, 2016, doi: 10.1080/23311916.2016.1177156. [40] p. ahmed ali sohu (quaid-e-awam university of engineering, science and technology nawabshah, sindh, “study and analysis of the potential of rice husk (biomass) as a viable source of energy in larkano and kamber shahdadkot districts of sindh.” [41] p. forster et al., “bounding the role of black carbon in the climate system : a scientific assessment bounding the role of black carbon in the climate system : a scienti fi c assessment,” no. november 2017, 2013, doi: 10.1002/jgrd.50171. [42] g. h. m. j. s. de silva, s. vishvalingam, and t. etampawala, “effect of waste rice husk ash from rice husk fuelled brick kilns on strength , durability and thermal performances of mortar,” constr. build. mater., vol. 268, p. 121794, 2021, doi: 10.1016/j.conbuildmat.2020.121794. [43] l. q. luu and a. halog, “rice husk based bioelectricity vs. coal-fired electricity: life cycle sustainability assessment case study in vietnam,” procedia cirp, vol. 40, pp. 73–78, 2016, doi: 10.1016/j.procir.2016.01.058. [44] j. singh, “overview of electric power potential of surplus agricultural biomass from economic, social, environmental and technical perspective a case study of punjab,” renew. sustain. energy rev., vol. 42, pp. 286–297, 2015, doi: 10.1016/j.rser.2014.10.015. [45] m. a. salam, k. ahmed, n. akter, and t. hossain, “sciencedirect a review of hydrogen production via biomass gasification and its prospect in bangladesh,” int. j. hydrogen energy, vol. 43, no. 32, pp. 14944–14973, 2018, doi: 10.1016/j.ijhydene.2018.06.043. [46] m. uzair, s. s. sohail, n. u. shaikh, and a. shan, “agricultural residue as an alternate energy source: a case study of punjab province, pakistan,” renew. energy, vol. 162, pp. 2066–2074, 2020, doi: 10.1016/j.renene.2020.10.041. [47] j. logeswaran, a. h. shamsuddin, a. s. silitonga, and t. m. i. mahlia, “prospect of using rice straw for power generation: a review,” environ. sci. pollut. res., vol. 27, no. 21, pp. 25956–25969, 2020, doi: 10.1007/s11356-020-09102-7. [48] a. o. avcıoğlu, m. a. dayıoğlu, and u. türker, “assessment of the energy potential of agricultural biomass residues in turkey,” renew. energy, vol. 138, pp. 610–619, 2019, doi: 10.1016/j.renene.2019.01.053. [49] s. m. safieddin ardebili, “green electricity generation potential from biogas produced by anaerobic digestion of farm animal waste and agriculture residues in iran,” renew. energy, vol. 154, pp. 29–37, jul. 2020, doi: 10.1016/j.renene.2020.02.102. [50] m. kashif et al., “untapped renewable energy potential of crop residues in pakistan: challenges and future directions,” j. environ. manage., vol. 256, no. september 2019, p. 109924, 2020, doi: 10.1016/j.jenvman.2019.109924. [51] m. r. abedin and h. s. das, “electricity from rice husk: a potential way to electrify rural bangladesh,” int. j. renew. energy res., vol. 4, no. 3, pp. 604–609, 2014, doi: 10.20508/ijrer.15831. [52] h. zhang et al., “a laboratory study of agricultural crop residue combustion in china: emission factors and emission inventory,” atmos. environ., vol. 42, assessment of rice residues as potential energy source in pakistan (pp. 41 53) sukkur iba journal of emerging technologies sjet | vol. 5 no. 1 january – june 2022 53 no. 36, pp. 8432–8441, nov. 2008, doi: 10.1016/j.atmosenv.2008.08.015. [53] m. adnan, j. ahmad, s. farooq, and m. imran, “a techno-economic analysis for power generation through wind energy : a case study of pakistan,” energy reports, vol. 7, pp. 1424–1443, 2021, doi: 10.1016/j.egyr.2021.02.068. [54] g. of p. finance division, pakistan economic survey report 2018-19. 2020. [55] a. ahmed, s. hidayat, m. s. abu bakar, a. k. azad, r. s. sukri, and n. phusunti, “thermochemical characterisation of acacia auriculiformis tree parts via proximate, ultimate, tga, dtg, calorific value and ftir spectroscopy analyses to evaluate their potential as a biofuel resource,” biofuels, vol. 12, no. 1, pp. 9–20, 2021, doi: 10.1080/17597269.2018.1442663. [56] a. abdullah et al., “potential for sustainable utilisation of agricultural residues for bioenergy production in pakistan: an overview,” j. clean. prod., vol. 287, p. 125047, 2021, doi: 10.1016/j.jclepro.2020.125047. [57] s. reza, a. ahmed, w. caesarendra, and m. s. a. bakar, “acacia holosericea : an invasive species for bio-char , bio-oil , and biogas acacia holosericea : an invasive species for bio-char , bio-oil , and biogas production,” no. april, 2019, doi: 10.3390/bioengineering6020033. [58] m. danish, m. naqvi, u. farooq, and s. naqvi, “characterization of south asian agricultural residues for potential utilization in future ‘ energy mix ,’” energy procedia, vol. 75, pp. 2974–2980, 2015, doi: 10.1016/j.egypro.2015.07.604. [59] u. u. rehman zia, t. ur rashid, w. n. awan, a. hussain, and m. ali, “quantification and technological assessment of bioenergy generation through agricultural residues in punjab (pakistan),” biomass and bioenergy, vol. 139, no. july, p. 105612, 2020, doi: 10.1016/j.biombioe.2020.105612. [60] s. butt, i. hartmann, and v. lenz, “bioenergy potential and consumption in pakistan,” biomass and bioenergy, vol. 58, pp. 379–389, 2013, doi: 10.1016/j.biombioe.2013.08.009. [61] eaz. husnain, “02-agriculture finl,” pp. 19–40, 2016, [online]. available: http://www.finance.gov.pk/survey/chapters_17/02agriculture.pdf. [62] m. hiloidhari, d. das, and d. c. baruah, “bioenergy potential from crop residue biomass in india,” renew. sustain. energy rev., vol. 32, pp. 504–512, 2014, doi: 10.1016/j.rser.2014.01.025. [63] a. milbrandt, r. overend, a. milbrandt, and r. overend, “assessment of biomass resources in afghanistan assessment of biomass resources in afghanistan,” no. january, 2011. [64] k. k. c. k. perera, p. g. rathnasiri, s. a. s. senarath, and a. g. t. sugathapala, “assessment of sustainable energy potential of non-plantation biomass resources in sri lanka,” vol. 29, pp. 199– 213, 2005, doi: 10.1016/j.biombioe.2005.03.008. [65] a. k hossain and o. badr, “prospects of renewable energy utilisation for electricity generation in bangladesh,” renew. sustain. energy rev., vol. 11, no. 8, pp. 1617–1649, 2007, doi: 10.1016/j.rser.2005.12.010. [66] j. singh, b. s. panesar, and s. k. sharma, “energy potential through agricultural biomass using geographical information system-a case study of punjab,” biomass and bioenergy, vol. 32, no. 4, pp. 301–307, 2008, doi: 10.1016/j.biombioe.2007.10.003. [67] d. g. streets, k. f. yarber, j. h. woo, and g. r. carmichael, “biomass burning in asia: annual and seasonal estimates and atmospheric emissions,” global biogeochem. cycles, vol. 17, no. 4, 2003, doi: 10.1029/2003gb002040. [68] m. m. iqbal and a. m. goheer, “greenhouse gas emissions from agro-ecosystems and their contribution to environmental change in the indus basin of pakistan,” adv. atmos. sci., vol. 25, no. 6, pp. 1043–1052, 2008, doi: 10.1007/s00376-0081043-z. [69] x. zhang, y. lu, and x. qian, “a high-resolution inventory of air pollutant emissions from crop residue burning in china,” atmos. environ., vol. 213, no. september 2018, pp. 207–214, 2019, doi: 10.1016/j.atmosenv.2019.06.009. [70] g. r. carmichael, biomass burning in asia : annual and seasonal estimates and atmospheric emissions biomass burning in asia : annual and seasonal estimates and atmospheric emissions, no. june. 2014. abbreviations iea, international energy agency; fy, fiscal year; rh, rice husk; rs, rice straw; m, moisture level; tep, theoretical energy potential; aep, available energy potential; lhv, lower heating value; co, carbon mono oxide; co₂, carbon dioxide; no, nitrogen mono oxide; no₂, nitrogen di oxide; nox, nitrogen oxides; sox, sulphur oxides; ghg, green house gases; pm, particulate matter; mt co₂-eq, million tons co₂ equivalent; ef, emission factor; toe, tons of oil equivalent; gwh, gega watt hour; rpr, residue to crop production ratio; mj, mega joule; tj, tera joule; kg, kilo gram; gg, gega grams; usd, united states dollar; gdp, gross domestic product. paper title (use style: paper title) vol. 1, no. 2 | july december 2018 sjet | issn: 2616-7069 | vol. 1 | no. 2 | © 2018 sukkur iba 33 electric field distribution in transformer bushing zubair ali1, mohsin ali tunio2, nadeem ahmed tunio2, shazia feroz3 abstract the bushings are insulating devices of the power system they allow electrical conductors to pass current and resist the flow of current to the conducting tanks in case of transformers and circuit breakers. these bushings are typically made of porcelain material. the bushing must be designed to withstand electrical as well as mechanical stresses. the electric field stresses may develops the leakage paths within the insulation and if these stresses increased beyond the dielectric strength of insulation, it may puncture the bushing insulation and will allow the electric current to pass through earthed material causing burning and arcing. mostly the electric field is not uniformly across the bushing therefore, a simulation is carried out to analyze and calculate the characteristics of electric field distribution in this paper, a transformer porcelain solid type bushing with oil as cooling and dielectric material is used. the finite element analysis (fem) technique is used to calculate electric field distribution along the solid type bushing transformer. it is projected that the results will provide an improved understanding of the ef distribution on the bushing outlet. this study may also assist in scheming hv bushing which can reduce the magnitude ef in the bushing. keywords: bushing, electric field (ef) distribution, finite element analysis (fea). 1. introduction hv bushing insulators are used to provide weather proof protection for the exposed ends of transformer. a bushing consists of a hollow insulating line from which hv conductor passes through an earthed wall, such as the metal tank that encloses an oil insulated transformer. the bushing insulates the hv conductor from earth and also provides a means of mechanically supporting the conductor. the bushings connect the transformer windings, supply line and insulate the feeder via 1 master of engineering student, department of electrical power engineering, mehran university of engineering and technology shaheed zulfiqar ali bhutto campus khairpur mir’s lecturer, vocational training centre khairpur, sukkur iba university corresponding email: zubairaliphulpoto@yahoo.com 2 department of electrical engineering, mehran university of engineering and technology shaheed zulfiqar ali bhutto campus khairpur mir’s 3 assistant professor, benazir bhutto shaheed university of engineering technology & skill development khairpur mir’s. conductor from the main tank of the transformer. according to the electrical and physical observation, bushing is the feeblest part of the transformer. besides hv bushing is the connection between outer and inner insulating schemes. the hv is fed into the transformer vessel and has to endure high loads, the electric field strength, mechanical forces, chemical loads and contaminations because of environmental and thermal pollution. for this reason, the bushings plays significant role in the operation of hv equipment [1]. mailto:zubairaliphulpoto@yahoo.com zubair ali (et al.), electric field distribution in transformer bushing (pp. 33 38) sukkur iba journal of emerging technologies sjet | volume 1 no. 2 july – december 2018 © sukkur iba university 34 the reliability of bushing is crucial for the operation of the transformer. bushings mechanically support external conductors and provide insulation from earth as the conductors are fed into the transformer tank. moreover, bushings are one of the important elements of transformers and it was found to be the most common reasons of disastrous breakdown of transformers and nearby protective devices [2]. the transformers are one of the most intentional and expensive equipment of electrical power system. it was found from past literature that almost 25 to 30% of transformer breakdown are due to the bushing failure [3-5]. since transformer bushings have no moving parts, most failures are attributed to insulation deterioration from moisture ingress [6] and electrical discharges. the bushing represents only a small fraction of the power transformer cost but their failure is often catastrophic. failures do not only damage the transformer but can often cause significant damage to equipment in the proximity and consequently causes significant disruption. the study of the ef distribution along outer surface of the bushing is of key importance as it is used to evaluate the potential initiation of partial discharges. the reliability of bushing is crucial for the operation of the transformer. bushings mechanically support external conductors and provide insulation from earth as the conductors are fed into the transformer tank [4]. the majority of bushings in the real practice are as old as the transformers. so monitoring the bushing condition and its maintenance is necessary. all hv bushings should be examined frequently every 3-5 years. during inspection if deterioration sign is found then bushing should be examined every 6 months and detached from service if the tests display a hazardous condition [2]. the commencement of bushing failure is not easily detectable at the initial stage that could later lead to an unwanted failure of the bushing, even though breakdown of the transformer. insulation breakdown is one of the severe failures of transformers which can produce extensive financial losses of the utility. consequently, utilities are recommended to continually check the conditions of transformers to avoid unwanted power outage and decrease failure rate. however, the formation of voids and air bubbles during modeling, installation and operation of insulating equipments is the main cause of insulator flashover and deterioration of power equipments. the presence of voids and air bubbles inside the dielectric material has lesser value of permittivity than the surrounding insulating material and higher electric field stresses that could lead to formation of weak spots in the insulation. in power transformer, the oil-paper insulation has been extensively incorporated in the designing of bushing structures due to its decent heat transfer and electrical properties. though, lengthy experience to severe electrical, mechanical and thermal stresses can weaken the oil vital possessions and split the paper insulation bonds resulting in the production of water, carbon dioxide, carbon monoxide. partial discharge (pd) activity can be generated if air bubbles are found in the insulation and can carbonize the material (insulation) forming conducting paths which can ultimately short out bushing layers. the lack of mechanical and thermal stresses could also be the cause of lack of continuity of the conducting bushings and arcing [2]. therefore, transformer bushings have been designed in such a way that reduces field stresses at transformer insulation. 2. mathematical formulation the distribution of ef is obtained using the electric potential (ep) equation. the basic principal field equations of the model are. f d  (1) zubair ali (et al.), electric field distribution in transformer bushing (pp. 33 38) sukkur iba journal of emerging technologies sjet | volume 1 no. 2 july – december 2018 © sukkur iba university 35 0   f f j t  (2) where equation 1 and 2 shows the field model and current continuity equations respectively. , f  and d are the free current density, charge density and the electric displacement field respectively. 3. model description the ‘2d axial symmetry’ model was built in comsol multi-physics; the ‘quasistatic electric’ is selected under the ‘ac /dc module’ to solve the ef distribution. figure 1 shows a transformer bushing model and its dimensions and components. to model the distribution of ef along surface of the bushing (outer), the model is enclosed by air. the boundary conditions for transformer bushing model geometries are given in table i and the associated material properties used to set the sub domains are given in table ii. figure 2 and 3 shows the 2d axial-symmetric model geometry, the mesh elements and the boundaries for calculation of electric field distributions. fig. 1. 2d transformer bushing model [7]. (a) (b) fig. 2. 2d axial-symmetric transformer bushing (a) model geometry and (b) with meshing. f j zubair ali (et al.), electric field distribution in transformer bushing (pp. 33 38) sukkur iba journal of emerging technologies sjet | volume 1 no. 2 july – december 2018 © sukkur iba university 36 table i. model boundary conditions boundary line boundary condition description green and black line electric potential conductor boundaries red dotted line axial symmetry boundaries along r=0 line pink line floating potential outer surface of the cap blue line continuity bushing interior boundaries fig.3. bushing model geometry with boundaries. table ii. sub-domain settings in model geometry. 4. simulation results the simulation of ef distribution in the developed model is shown in figure 4. the entire structure length is 385 mm, diameter of conductor and bushing (plate) is 12 mm and the 155mm respectively. the applied voltage is 11 kv, the magnitude of maximum ef is observed at the cap of porcelain as this part of the cap has floating potential boundary. the maximum ef is found to be 805.887 v/m at the porcelain cap (edge) region. the oil as the insulation material of the conductor reduces the ef magnitude around the conductor region. fig. 4. simulated electric field distribution in transformer bushing. figure 5 shows the plot of magnitude of the ef in the developed model. it has been found that the magnitude of the ef is not uniform and is because of materials having different permittivity value in the structure and boundary condition. for the developed model, the electric field is zero after r = 0 m because of the conductor region. the next region after the conductor consists of the insulation material. the magnitude of ef is at peak at the nearest area to the conductor and drops within the insulation material at the site material permittivity 𝛆𝐫 air 1 porcelain cap 6 aluminium 1 oil 2.3 zubair ali (et al.), electric field distribution in transformer bushing (pp. 33 38) sukkur iba journal of emerging technologies sjet | volume 1 no. 2 july – december 2018 © sukkur iba university 37 far away from the conductor. after the first and second insulation layer as shown in figure 5, the magnitude of electric field is nearly identical within the bushing region made of the porcelain insulation material. there is discontinuous electric field between the insulation material porcelain and the air layer next to it, because the air permittivity is different. fig. 5. cross-sectional view of electric field in the bushing model figure 6 shows the magnitude of ef at a definite point in the insulation material subjected to the material permittivity for the developed model. it has been found in the developed model that the magnitude of electric field decreases when material permittivity is higher. fig. 6. relation between the electric field and permittivity of the insulating material. the permittivity defines the capability of the insulation material to align the ef. therefore, a higher permittivity of the insulation means that the aptitude of the insulation to align the ef is better, resulting in less ef attentiveness in the insulation material. for figures 6, the magnitude of ef in the bushing subjected to the permittivity of the insulation material. 5. conclusion the two dimensional axial symmetry model of transformer bushing was made through the finite element analysis (fea) technique. the simulation was done to examine the distribution of ef in transformer bushing. the effect of the bushing permittivity has also been studied. from the simulation results, it was found that the high ef is mainly concentrated at the edge of aluminum cap and bushing plate. it was also concluded that the magnitude of ef in the bushing is inversely proportional to the permittivity hv bushing material. references [1]. sumereder, c. and muhr. m. "dielectric response measurements at high voltage bushings". international.conference on condition monitoring and diagnosis pp.1150-1153. 2008 [2]. setayeshmehr,a.,"on-line monitoring and diagnoses of power transformer bushings," ieee transactions on dielectrics and electrical insulation, vol. 13, pp. 608-615. 2006 [3]. lokhanin,a.k, g.y. shneider, v.v. sokolov, and v.m. chornogotsky, "internal insulation failure mechanisms of hv equipment under service conditions," cigre, pp. 16.2002. [4]. lord,t., and hodge,g, "on-line monitoring technology applied to hv bushings,". avo technical paper pp. 03-08.2005. 700 750 800 850 900 950 2 4 6 8 10 e le c tr ic f ie ld v /m m permittivity of insulating … zubair ali (et al.), electric field distribution in transformer bushing (pp. 33 38) sukkur iba journal of emerging technologies sjet | volume 1 no. 2 july – december 2018 © sukkur iba university 38 [5]. pukel,g.j., h. m. muhr and w. lick. "transformer diagnostics: common used and new methods," international conference on monitoring and diagnosis, cmd changwon, korea. vol. 36607, p. 15463.2006. [6]. j. s. graham, "high voltage bushings," in high voltage engineering and testing, h. m. ryan, ed. london, united kingdom: the institution of electrical engineers, 2001, ch. 12, pp. 405-434. [7]. http://www.hivoltinsulators.com/uploa d/20171129/a4004b4c9e207d55c9355c 6e3d0471ea.jpg. [8]. t. seghir, d. mahi, t. lebey, and d. malec, “analysis of the electric field and the potential distributions in cavities inside insulation electric materials,”comsol users conference, paris, france, 2006. [9]. a.e. davies and g. chen, “electric stress distribution in polymeric insulation containing defectd sites and space charges,” the international journal for computation and mathematics in electrical and electronic engineering, vol. 11, no. 1, pp. 237-240, 1992. [10]. lijun jin; yifei xue; bonan zhao; jie chen; wenhao zhang “electric field calculation and insulation analysis of high voltage insulating bushing”. electric power equipment switching technology (icepe-st), international conference, 2013. [11]. amit kumar mehta; r. n. sharma; sushil chauhan; s. d. agnihotri “study and diagnosis of the power transformer bushing insulation system”. ieee pulsed power conference, 2011. http://www.hivoltinsulators.com/uploa http://www.hivoltinsulators.com/uploa format template vol. 6, no. 1 | january – june 2023 sjet | p-issn: 2616-7069 |e-issn: 2617-3115 | vol. 6 no. 1 january – june 2023 44 mobile apps development: towards incorporating regional and national languages in flutter app kamran khan1, dr. isma farah siddiqui1, salahuddin saddar1, hina hussain1, umair ayaz1, and sadaquat ali ruk2 abstract: as technology spreads rapidly worldwide, people from different countries have started using portable devices like phones, tablets, or laptops. with the growing trend of globalization, people worldwide are now using these portable devices to access various apps and services, which means that apps should be developed in a way that caters to the needs of these diverse users. most apps are unavailable in multiple languages, which can be frustrating for users who are not fluent in the language in which the app is developed. developing a multilingual app and taking input in multiple languages is still a headache for developers. this research aims to develop a multilingual keyboard package for flutter apps. this package allows developers to add a multilingual keyboard to their apps easily and quickly. the package at this stage only supports english, urdu, and sindhi languages. the proposed approach also added some special characters, a numeric keyboard, and language keyboards. the keyboard interface is highly customizable, developers can customize it as per their preferences, and they can change different properties of keyboards, including key text color, key background color, keyboard background color, and shadows. this package allows users to enter text in multiple languages in the same or different input fields. after the publication of this package, the authors conducted a survey in which questions like the performance, accuracy, and interface of the keyboards were asked of the developers. in the survey, researchers asked for the developer's suggestions and feedback about keyboards and other languages they want us to add to the package. keywords: multilingual keyboards, flutter package, in-app keyboards. 1. introduction we live in an era where technology is becoming more and more powerful and compact. people love to use portable devices to carry them easily wherever they go. portable devices allow users to stay connected with 1department of software engineering, mehran university of engineering & technology, jamshoro, pakistan. 2department of computer science, shah abdul latif university, ghotki, pakistan. corresponding author: isma.farah@faculty.muet.edu.pk their family, friends, colleagues, clients, bosses, and team leads. mobile devices have become necessary for everyone, and mobile technology is evolving quickly. mobile traffic has increased than desktop traffic after november 2019 [1]. as the usage of mobile devices has increased, new companies and technologies are coming into being. android, ios, windows, and kamran khan (et al.), flutter apps development: towards incorporating regional and national languages in flutter apps (pp. 44 53) sukkur iba journal of emerging technologies sjet | vol. 6 no. 1 january – june 2023 45 blackberry are operating systems currently used in mobile devices. different development technologies or languages are used to develop an application for these os. developers must maintain a separate code base for each app which is a lengthy and costly process. to reduce the time and cost of the development process, developers prefer to choose crossplatform technologies. cross-platform app development is a way to develop apps for multiple operating systems with a single code base. flutter is a framework used to develop cross-platform apps which will run on both android & ios. flutter reduces the complexity, loc, and development time to approximately 50 percent [2]. other crossplatform technologies use a bridge to communicate with the native language, but flutter removes this bridge and runs the app in an environment mostly built on c++ [3]. unlike other cross-platform technologies, flutter does not convert code to a native language and does not use a web wrapper to run code. flutter uses its engine increasing performance and load ui components efficiently [4]. since flutter is new technology evolving daily, so is its community. flutter contributors are publishing libraries rapidly on https://pub.dev/. https://pub.dev is the platform where flutter libraries are published. besides publishing the library on https://pub.dev/, developers create a public repository on github to push the library's code. developers can read all the library code and open an issue on github if they find any. developers can also contribute to the library by github pull requests. flutter 2 was released on 3rd march 2021, with the support of null-safety [4], which was very rare in other mobile application development technologies [5]. null-safety means the app will not encounter a null-pointer exception at runtime. flutter 2 and onwards, all the versions of flutter support null-safety and old projects should be migrated to null-safety to debug and deploy apps. 2. literature review studies on text input methods for mobile devices started with the invention of smartphones. many researchers have researched keyboard types, alphabet placement, and multilingual keyboards. most students use keyboards for the whatsapp application, concluded by mustafa serkan abdusselam through a survey in which 238 candidates participated [6]. a survey concluded that the study on keyboards should be done on the end-user side, where users use keyboards with their personalization [7]. phone manufacturers have done a comparative study on keyboards, and they discussed demanded features, lacking areas of keyboards, and how typing speed can be increased [8]. the octopus keyboard is the fastest, producing fewer errors than t+ and curve keyboards [9]. 3. overview of selected technology flutter is a ui toolkit developed by google [15]. flutter is not a programming language. instead, it is an sdk with prewritten code that includes ready-to-use and customizable widgets [12]. flutter sdk is built on dart programing language; in flutter, every application is written using dart programming language. 3.1. flutter flutter is an open-source, cross-platform framework for developing high-quality, highperformance apps for various operating systems, including android, ios, windows, linux, mac, and google fuchsia, from a single codebase [10]. google publicly released flutter in may 2017. google has chosen flutter as the application-level framework for its next-generation operating system. flutter is unique because it relies on the device's oem widgets rather than consuming web views [11]. flutter renders each view component using its highperformance rendering engine. flutter's engine, primarily written in c++, supports https://pub.dev/ https://pub.dev/ https://pub.dev/ kamran khan (et al.), flutter apps development: towards incorporating regional and national languages in flutter apps (pp. 44 53) sukkur iba journal of emerging technologies sjet | vol. 6 no. 1 january – june 2023 46 low-level rendering via google's skia graphics library or the custom "impeller" graphics layer. 3.1.1 features of flutter  flutter's hot reload feature allows seeing changes in the code immediately reflected on the ui [15]. this speed up the process of working on the application's ui. as a result, developers can correct errors more quickly and save costs and time.  using flutter, developers can write code that works on multiple platforms at the same time [2][3][15]. it saves developers or companies time, money, and effort.  in flutter, every ui component is defined as a widget. text, buttons, padding, or a menu are all examples of widgets [2][12]. flutter can generate complex and customized widgets according to the application's requirements.  unlike most cross-platform frameworks, flutter does not use intermediate code representations or interpretations. the flutter application is written directly into machine code [1], eliminating any performance issues caused by the interpretation process. flutter provides a fully compiled release application ahead of time. 3.2 dart programming language dart is a general-purpose, object-oriented programming language with c-style syntax that google created in 2011. to create an app with flutter, developers need to code in dart. like other programming languages such as java, kotlin, swift, and javascript, dart is easy to learn. according to google, dart is a client-optimized language for building fast apps on any platform. 4. methodology this section outlines the step-by-step procedure for creating, testing, and publishing a multilingual keyboard library. it also describes gathering alphabets, keyboard design, development, testing, and publishing on https://pub.dev. fig. 1 methodology diagram fig.1 describes a step-by-step process to develop, debug, and publish a multilingual keyboard library to https://pub.dev. the process starts with gathering the alphabet of languages (urdu, sindhi, and english). once the alphabet is gathered, the design phase starts. the development phase follows it, and after the development testing phase comes. once the package is stable enough for the community to use, then the package is published to https://pub.dev, and simultaneously code of the package is published to the github repository. 4.1 gathering alphabets the authors gathered alphabets of sindhi, urdu, and english languages from different kamran khan (et al.), flutter apps development: towards incorporating regional and national languages in flutter apps (pp. 44 53) sukkur iba journal of emerging technologies sjet | vol. 6 no. 1 january – june 2023 47 research papers. all the alphabets are gathered from valid sources. the urdu language consists of 37 fundamentals alphabets [13], and there is some character variation that is made by combining two or more alphabets, such as "کھ" which is the combination of 2 urdu alphabets, "ک," and "ھ." the sindhi language consists of 52 alphabets [14], and the english language has 26 capital alphabets and 26 small alphabets. all numbers from 0 to 9 have been taken for the numeric keyboard. moreover, for the special character keyboard, familiar special characters have been chosen for our daily lives. 4.2 keyboards design the next step after collecting the alphabet is designing the keyboards. two keyboards with special characters and numeric keys have been created, two for each language. we created two keyboards with 26 alphabets each because the sindhi language has 52 different letters. in the case of urdu, which uses a script with 37 alphabets, developers may need to create specialized keyboards to ensure that users can type in the language effectively. to accommodate the 37 alphabets, two keyboards were designed for urdu., one with 26 alphabets and the other with 11 remaining alphabets and some with a variation. two keyboards are designed for the english language, one for upper-case alphabets and the other for lower-case alphabets. 4.3 keyboards development after finishing the design, all the keyboards were developed and incorporated fundamental features of keyboards, such as adding space, new lines, jumping to the next field, and the done action. at the time of development, researchers focused on features and the ui of keyboards. the package is developed in such a way that developers can easily personalize keyboard ui in their apps. the developers can choose the ui of the keyboards of their choice. the keyboard 1 https://pub.dev 2 https://pub.dev/packages/artistic_multilingual_keyboards background color, key background color, key text color, key spacing, key shadows, and border-radius can be changed easily to achieve the desired ui. 4.4 testing once keyboards were developed testing phase was initiated. the keyboard design, accuracy, performance, and efficiency were tested in the testing phase. design issues were found, and the design phase was reinitiated to resolve those design issues. similarly, accuracy, performance, and efficiency issues were found and resolved in the development phase. 4.5 publishing package on the https://pub.dev after completing the testing phase, when the package was ready for the community to use, the package was published on https://pub.dev1. the package's name is "artistic multilingual keyboards" and is available at https://pub.dev2. 4.6 publishing source code on github the source code of the package is available on the github repository3. it is available for the community to contribute to the package. following are the ways the community can contribute to the package:  test and report if any issue is found.  resolve reported issues.  add a new feature to the package.  suggest some good changes. anybody can report an issue found on the package by simply opening an issue on the github repository and describing all the steps to reproduce the issue. one can add a new feature in the package by creating a new branch from the main and its pull request on the github repository. the code owner then reviews that pull request and merges the code into the main code. 3 https://github.com/kamran8545/artistic_multilingual_keyboards kamran khan (et al.), flutter apps development: towards incorporating regional and national languages in flutter apps (pp. 44 53) sukkur iba journal of emerging technologies sjet | vol. 6 no. 1 january – june 2023 48 5. tools & technologies  android studio is an ide used to develop mobile applications [16].  flutter sdk is a set of libraries containing the source code of the flutter framework [17].  dart sdk is a set of libraries containing the source code of the dart programing language on which the flutter framework is built [18].  flutter & dart plugins enable developers to develop flutter apps on android studio [19].  a mobile device for testing purposes could be a physical device or an emulator.  git is a tool to manage source code on the github repository or any other platform [20]. 6. results & discussion this research aims to develop a multilingual flutter package allowing developers to add multilingual keyboards to their applications. the proposed approach has chosen three languages sindhi, urdu, and english. along with these three languages keyboards a numeric keyboard and some special characters keyboards also been developed. by using this package developers can easily add in-app language specific keyboard in their apps. fig. 2 sindhi keyboard of 26 alphabets fig. 3 sindhi keyboard of remaining 26 alphabets kamran khan (et al.), flutter apps development: towards incorporating regional and national languages in flutter apps (pp. 44 53) sukkur iba journal of emerging technologies sjet | vol. 6 no. 1 january – june 2023 49 figures 2 and 3 show the sindhi language keyboards containing 26 alphabets each. fig. 4 urdu keyboard of 26 alphabets fig. 5 urdu keyboard of remaining 11 alphabets and with some variations fig. 4 shows the urdu language containing 26 alphabets, and fig. 5 shows the urdu language keyboards containing the remaining 11 alphabets and some alphabet variations. fig. 6 english uppercase keyboard fig. 7 english keyboard kamran khan (et al.), flutter apps development: towards incorporating regional and national languages in flutter apps (pp. 44 53) sukkur iba journal of emerging technologies sjet | vol. 6 no. 1 january – june 2023 50 figures 6 and 7 show the english language keyboards containing english uppercase and lower-case alphabets, respectively. 6.1 customized ui following are some customized designs of keyboards. by changing some properties of keyboards, desired design can be made. fig. 8 and fig. 9 show some ui customization, but it is not the only ui developers can use in their apps. ui of keyboards is highly customizable; they can change the keyboard background color, key background color, key text color, key shadow, key corners radius, and other properties to achieve their desired ui. fig. 8 customized ui fig. 9 customized ui 7. performance evaluation after the package's release, the researchers polled the flutter community. the survey's participants ranged in experience from beginners to seniors. 109 people in total took part in the survey. participants were questioned in the survey regarding the keyboard's ui, performance, accuracy, efficiency, etc. following are the few questions asked by developers: fig. 10 participants' experience level. kamran khan (et al.), flutter apps development: towards incorporating regional and national languages in flutter apps (pp. 44 53) sukkur iba journal of emerging technologies sjet | vol. 6 no. 1 january – june 2023 51 fig. 11 how frequently do participants use or see multilingual keyboards in mobile apps? fig. 12 rate the keyboard's ui from 0 to 10. fig. 13 are all the keyboards functioning correctly? fig. 14 are the keyboards typing alphabets with accuracy? fig. 15 are all the keyboards working fine when you are typing more rapidly? kamran khan (et al.), flutter apps development: towards incorporating regional and national languages in flutter apps (pp. 44 53) sukkur iba journal of emerging technologies sjet | vol. 6 no. 1 january – june 2023 52 fig. 16 should we add more languages to this package? s# language no of suggestions 1 french 6 2 hindi 6 3 arabic 8 4 spanish 7 5 chinese 4 6 japanese 3 7 pashto 4 8 german 3 9 russian 1 10 korean 3 11 punjabi 3 12 balochi 4 13 saraiki 1 14 brohi 1 15 xhosa 2 table. 1 suggested languages table.1 shows the language name, and no of times a language has been suggested to add to the package. fig. 17 rate this package from 0 to 10. 8. conclusion & future work in this research, an open-source flutter package has been developed and published to add multilingual support to flutter apps. by adding this package to their apps, developers can take input from users in multiple languages. they can take multilingual input in a single field or multiple fields. this package will reduce the efforts of end-users. they do not have to download multiple languages to their devices to input in multiple languages. the researchers also surveyed the developers to improve the package's performance, accuracy, and efficiency; moreover, they were asked about other languages developers want us to add to the package. this research further aims to add more languages to the package and improve its performance, accuracy, and efficiency by evaluating the conducted survey. references [1] tahsildar, aakanksha, et al. "application development using flutter." international research journal of modernization in engineering technology and science 2.08 (2020): 1262-1266. [2] olsson, matilda. "a comparison of performance and looks between flutter and native applications: when to prefer flutter over native in mobile application development." (2020). [3] ameen, siddeeq y., and dilkhaz y. mohammed. "developing cross-platform library using flutter." european journal kamran khan (et al.), flutter apps development: towards incorporating regional and national languages in flutter apps (pp. 44 53) sukkur iba journal of emerging technologies sjet | vol. 6 no. 1 january – june 2023 53 of engineering and technology research 7.2 (2022): 18-21. [4] "faq," flutter. [online]. available: https://docs.flutter.dev/resources/faq. [5] publication, i. j. r. a. s. e. t. (2021, 5th june). a research paper on a progress tracking application using flutter and firebase. international journal for research in applied science & engineering technology. retrieved 8th march 2022, from https://www.academia.edu/49135635/a_r esearch_paper_on_a_progress_tracking_ application_using_flutter_and_firebase [6] abdusselam, mustafa serkan. "a research on students' preferences for mobile onscreen keyboard." shanlax international journal of education 9.2 (2021): 46-53. [7] buschek, daniel, benjamin bisinger, and florian alt. "researchime: a mobile keyboard application for studying free typing behavior in the wild." proceedings of the 2018 chi conference on human factors in computing systems. 2018. [8] jog, yatin, and veronica singh. "smart keyboards: need of customization and personalization of mobile keyboards." int. journal of latest technology in engineering, management & applied science 3.9 (2014): 115-119. [9] cuaresma, justin, and i. scott mackenzie. "a study of variations of qwerty soft keyboards for mobile phones." proceedings of the international conference on multimedia and human-computer interaction-mhci. 2013. [10] hina hussain, kamran khan, faiza farooqui, dr. qasim ali arain, dr. isma farah siddiqui. "comparative study of android native and flutter app development." ksii the 13th international conference on internet (iconi) at jeju, south korea, 2021. 99-102. [11] aakanksha tashildar, nisha shah,rushabh gala,trishul giri and pranali chavhan. "application development using flutter." international research journal of modernization in engineering technology and science (2020): 1262-1266. [12] shreya a. bhagat, sakshi g. dudhalkar,prathmesh d. kelapure, aniket s. kokare, prof. sudesh a. bachwani. "review on mobile application development based." international journal for research in applied science & engineering technology (2022): 803-809. [13] khan, m. aamir, m. abid khan, and m. naveed ali. "design of urdu virtual keyboard." proc. conf on language & technology. 2009. [14] sodhar, irum naz, akhtar hussain jalbani, and muhammad ibrahim channa. "identification of issues and challenges in romanized sindhi text." editorial preface from the desk of managing editor… 10.9 (2019). [15] dagne, lukas. "flutter for cross-platform app and sdk development." (2019). [16] download android studio & app tools. android developers. (n.d.). retrieved 30th january 2023, from https://developer.android.com/studio [17] flutter. (n.d.). retrieved 30th january 2023, from https://flutter.dev/ [18] dart programming language. dart. (n.d.). retrieved 30th january 2023, from https://dart.dev/ [19] flutter & dart plugins. flutter. (n.d.). retrieved 30th january 2023, from https://docs.flutter.dev/getstarted/editor?tab=androidstudio [20] git. (n.d.). retrieved 30th january 2023, from https://git-scm.com/ https://www.academia.edu/49135635/a_research_paper_on_a_progress_tracking_application_using_flutter_and_firebase https://www.academia.edu/49135635/a_research_paper_on_a_progress_tracking_application_using_flutter_and_firebase https://www.academia.edu/49135635/a_research_paper_on_a_progress_tracking_application_using_flutter_and_firebase https://flutter.dev/ https://dart.dev/ format template vol. 4, no. 2 | july – december 2021 sjet | p-issn: 2616-7069 |e-issn: 2617-3115 | vol. 4 no. 2 july – december 2021 1 an energy efficient crypto suit for secure underwater sensor communication using genetic algorithm fozia hanif 1, urooj waheed2, samia masood2, rehan shams3, syed inayatullah1 abstract: with the advancement in technology, there has been a keen interest of researchers and industrial institutions in the use of underwater sensors networks (uwsn s). this study is devoted to the secure communication between the underwater sensors networks which are nowadays most widely used for oceanographic abnormalities, and to track submarines that perform the surveillance and navigation. but uwsns has its limita tions such as multipath, propagation delay, low bandwidth, and limited battery as compared to traditional wsns that causes a low life in comparison with wsns. secure communication in uwsns is more difficult due to the above-mentioned limitations which need ultralightweight components. there are many miscellaneous attacks due to which sensors can lose both data availability and integrity . in this study we have designed a computation and space efficient algorithm for secure underwater senor communication. the proposed algorithm will generate two-halves of the key through a genetic algorithm (ga). genetic algorithm is an evolutionary technique, that produces very good results in many engineering problems. in cryptography, the most important part is the key generation procedure that plays a major role in data transfer. the secure key is the basic requirement of data encryption and by the help of ga, this study provides a complex key generation procedure for one part of the key. genetic algorithm includes some basic steps such as initial population generation, crossover, and mutation. however, a new fitness function is introduced to enhance the efficiency of ga along with the different procedures of crossover and mutation. after that encryption algorithm is proposed for the secure communication between uwsns and its performance is evaluated based on throughput, running time, space usage, and avalanche effect. keywords: uwsns; security; cryptography; genetic algorithm; linear congruential procedure; pseudo-random number; avalanche affect. 1. introduction wireless sensor networks ha ve wide a pplica tions in fields such a s home, industry, environmenta l observa tion, milita ry monitoring, a nd disa ster relief [1]. recent a dva nces in wireless communications and electronics ha ve ena bled the development of 1 depa rtment of ma thematics, university of ka ra chi, ka ra chi, pa kista n . 2 depa rtment of computer science, dha suffa university, ka ra chi, pa kista n. 3 depa rtment of telecommunica tion engineering, sir syed university of engineering and technology, ka ra chi, pa kista n. corresponding author: ms_kha ns2011@hotmail.com sma ll low-cost sensor nodes tha t communicate over short dista nces. wireless sensor networks a re comprised of severa l sensor nodes that communica te via wireless technology. in this pa per, we will propose a new wa y of symmetric cryptogra phy for sending the da ta between underwa ter sensor networks with mailto:ms_khans2011@hotmail.com f. hanif (et al.), an energy efficient crypto suit for secure underwater sensor communication using genetic algorithm (pp. 01 17) sukkur iba journal of emerging technologies sjet | vol. 4 no. 2 july – december 2021 2 high security. in symmetric cryptogra phy, there is only one key which is responsible for both the encryption a nd decryption. therefore, the key genera tion procedure should be very complex to genera te a strong key to stop any intruders from guessing or detecting the key. the key genera tion procedure beha ves as a ba ckbone of a ny cryptogra phic a lgorithm; therefore, this study is going to use ga for genera ting the key for the encryption procedure. cryptogra phy ha s a lwa ys been a most importa nt requirement in the iot a pplica tion but a s the mode of communication cha nges the requirement of security changes as well but limita tions in underwa ter sensors a re more a s compa red to other wa ys of communica tion [3-4]. some fea tures of wsn a nd uwsns a re the sa me due to the but ha rsh environment of uwsns there a re more constra ined in uwsns a s compa red to wsn such a s unrelia ble communica tion cha nnels, dyna mic networks topology, insecure environment, a nd vulnera bility [5]. the proposed a lgorithm genera tes its key which is of 128 bits in two steps: the first ha lf of the key will be ca lcula ted by the a nchor node through genetic algorithm (ga) procedure a nd the rest of pa rt of the key is ca lcula ted by the sensor node by using some other procedure a nd merger of these two pa rts will be the fina l key [6, 7]. to a void the pa ssive a tta ck here the da ta fra me will be sent through some a uthentica tion code to a void the a tta ck a nd a fter receiving the fra me sensor will simula te the code by itself to ma tch with the incoming code a fter this ma tching of a uthentication code the data fra me can open by receiving sensor otherwise it will disca rd the da ta fra me. the proposed resea rch scheme will ca lcula te the two pa rts of the key sepa ra tely, a uthentication codes, a nd then it performs the process of encryption a nd decryption. the novelty of this study is tha t ga ha s never been used in da ta communica tion of uwsns and our result session will prove tha t how ga will give more ra ndomness to the key genera tion procedure a nd this complete lightweight process will not only enha nce the security but a lso provides low computa tional complexity [8-9]. this pa per is orga nizing a s follows: after the introduction section 1.1 gives the litera ture review, section 2 indica tes the security issues in underwa ter sensors communica tion, section 3 discusses genetic a lgorithm a long with a brief discussion of its steps, a fter tha t this pa per gives key genera tion procedure through ga with deta ils steps implementa tion then section 4 gives the ca lcula tion of a uthentica tion code a nd final key forma tion, section 5 shows the encryption for underwa ter communication and decryption procedure a lso. section 5 indica tes a n a na lysis of the result by using different pa ra meters and shows the security a na lysis a nd in the end, we ha ve the conclusion a nd references. 2. literature review cryptogra phy ha s been a ma jor requirement for ma ny yea rs for a ny type of communica tion system, but the cryptogra phic a lgorithm is dependent upon the environment through which its communica tion occurs. ma ny resea rchers ha ve ma de their efforts to perform underwa ter communication but due to the limita tions of the underwa ter environment, it is not so ea sy to perform underwa ter communica tion smoothly [10,11]. severa l ga-ba sed a lgorithms ha ve been ma de for secure cryptogra phy [12,13], a lso ma ny resea rchers ha ve proved tha t the performa nce of ga produced better results [14] but for underwa ter sensor communica tion, ga ha s never been used before. soniya goya t in [15] sa ys tha t if the quality of the ra ndom numbers produced by the method is good then the key genera tion is a lwa ys better. ultra -lightweight cryptogra phy ha s been presented for underwa ter sensor networks tha t repla ce the s-box with 8 round itera tion block cipher a lgorithms [16]. the effort of modifica tion of rc6 ha s a lso been ma de by [17]. due to the compu ta tional complexity symmetric cryptogra phy gives better results in underwa ter sensors as compa red to a symmetric cryptogra phic a lgorithm [18, 19]. f. hanif (et al.), an energy efficient crypto suit for secure underwater sensor communication using genetic algorithm (pp. 01 17) sukkur iba journal of emerging technologies sjet | vol. 4 no. 2 july – december 2021 3 another improvisa tion for secure communica tion in underwa ter sensors wa s presented by [20], which dea ls with xor, leftright shift for the lower computational cost and genera tes the ra ndom key by pseudo -random number genera tor tha t reduces the spa ce stora ge. to reduce the computational burden [21] ha s a lso presented secure underwa ter communica tions ba sed on fully ha shed mqv. gove nitin kuma r ka ur in [22] uses the concept of bra in mu wa ves, genetic a lgorithms, a nd pseudora ndom bina ry sequence. fa iya z ahma d ha s proposed a model tha t ma kes use of ga to genera te pseudo-ra ndom numbers [23]. the litera ture review shows tha t a lthough a lot of efforts ha ve been ma de to improve the security of uwsns through different encryption a lgorithms, most of them a re both spa ce a nd complexity expensive. the need to design a scheme tha t utilizes the minimal spa ce a nd computational ca pa cities of the underwa ter sensors while providing a completely secure a nd efficient communica tion still exists. the proposed model a ddresses a ll these issues a nd provides a secure wa y of communication using minimal sensor resources. 3. security issues in underwater sensors communication ma ny a pplica tions a re a ssocia ted with underwa ter environments such as surveilla nce, ocea n monitoring, a nd disa ster mitiga tion to mea sure the level of the sea due to the melting process of the ice sheet. all this ca n be possible due to ra ndomly pla ced underwa ter sensors tha t collects some important hydrologic da ta for exa mple pressure, tempera ture, a nd sa linity. the most important ta sk which is performed by underwa ter sensors is to sense the da ta a nd pass it to the releva nt ba se sta tion, but security threa ts a re the ma jor issue while tra nsferring the da ta [24-26]. there a re ma ny constra ints during underwa ter communica tion. unsns ca n be ea sily a ffected by va rious a tta cks and ma licious threa ts, these a tta cks ca n be either a ctive or pa ssive [27]. a pa ssive a tta ck is an a ttempt by miscella neous nodes to obta in the tra nsmitted da ta without cha nging the opera tion tha t’s why it is very difficult to detect. wherea s a ttra ctive a ttacks a re ea sy to indica te, a nd it tries to delete, a lter distra ct the tra nsmitted da ta in the network. the a ctive a tta ck mostly a ttempts by externa l nodes which do not belong to the networks. the main fea ture of security in uwsns a re key ma na gement, intrusion ma na gement, trust issues, secure loca liza tion, secure synchroniza tion, a nd routing security [28, 29]. to a chieve the security requirements a nd setup or mecha nism should be proposed tha t protect uwsns from these a bove-mentioned treats [30]. the ma in goa ls of cryptogra phy a re repudia tion, integrity, confidentia lity, and a uthentication. the encryption schema should sa tisfy cha llenges of underwa ter such tha t, it should be a da ptable for underwa ter tra nsmission, lower computa tion with less overhea d, cost, a nd energy-efficient and ensure high security. the ma in fea tures of any encryption a lgorithm of uwsns a re to provide integrity a nd confidentia lity in between nodes using less spa ce a nd high security with lower computations [31,32]. in this study, we develop a n a lgorithm that not only genera tes the key using the genetic algorithm but a lso provides a n encryption scheme for secure communica tion that proves to be efficient in terms of spa ce usa ge, running processing time, a nd the a va lanche effect. 3.1. system architecture the underwa ter environment consists of va rious sensor nodes tha t ca n be a ble to communica te with ea ch other. the communica tion between underwa ter sensor nodes is done with the help of a sink node and a ba se sta tion which route the da ta from one sensor to a nother. for the proposed a rchitecture it is a ssumed tha t a ll sensors can sense, communicate, a nd able to ca lcula te. it is a well-known fa ct tha t routing the da ta between underwa ter sensor nodes is not that much ea sier a s compa red to tra ditional wireless sensor networks (wsns), beca use of the continuous movement of the sensors in the ocea n. the ma in purpose of underwa ter f. hanif (et al.), an energy efficient crypto suit for secure underwater sensor communication using genetic algorithm (pp. 01 17) sukkur iba journal of emerging technologies sjet | vol. 4 no. 2 july – december 2021 4 sensors is to sense the da ta from the environment a nd rout them between the nodes. the figure 1 shows the uwsns environment where different nodes such a s sink node, sensor node a nd the ba se sta tion. fig. 1. system a rchitecture for underwa ter a coustic networks 4. genetic algorithm a genetic a lgorithm is a n evolutiona ry procedure tha t is ba sica lly used to optimize ma ny problems like shortest pa th, intrusion in wsn, ba ndwidth utiliza tion, a nd ma ny more [33, 34]. the rea son behind using the genetic a lgorithm in genera ting the key in uwsns is, tha t cryptogra phy through ga provides the lightweight complexity which is the mea sure requirement within the uwsns. ga a pproach is completely ra ndom which enha nces the cryptogra phic encryption a nd decryption, a lso the elitism genetic a lgorithm sta rts with the ra ndom results ca lled chromosomes which ca n be genera ted through ma ny ra ndom procedures, is considered a s the results of the given problem [35]. furtherly these ra ndomly genera ted results ca n be ma de more a ccurate by using different steps of genetic procedure which a re fitness mea sure, crossover, a nd muta tion. to get more a ccura te results through ga it is very importa nt to ha ve a strong fitness function tha t a pplies on initia l ra ndom genera tion to mea sure its fitness. the fitness function decides which chromosome ca n go for the process of crossover. in crossover two chromosomes will produce two more fitted chromosomes tha t ca n be tested a ga in, by using a fitness function. after getting better chromosomes from crossover, we a pply muta tion to a chieve globa l optima from loca l optima [36]. in the proposed a lgorithm we ha ve used the a bove-mentioned steps of genetic a lgorithm to genera te the ha lf pa rt of the key for symmetric cryptogra phy. these tra ditional steps of ga do ha ve ma ny va ria tions a ccording to a scena rio a nd environment [37]. we ha ve performed these steps in our own wa y by ma king the fitness function a ccording to the suita ble pa ra meters tha t a re rela ted to the conditions of the cryptogra phic a pproa ch. f. hanif (et al.), an energy efficient crypto suit for secure underwater sensor communication using genetic algorithm (pp. 01 17) sukkur iba journal of emerging technologies sjet | vol. 4 no. 2 july – december 2021 5 4.1. key generation procedure the cryptogra phic a lgorithm sta rts with the process of key genera tion; here we a re genera ting the ha lf pa rt of 64 bits key with the help of a genetic a lgorithm (ga) which is an evolutiona ry-based procedure. the rea son behind choosing ga for the key genera tion is, tha t it is completely a ra ndom procedure which ma kes key guessing very difficult, a nd to make this even more difficult the rema ining ha lf part of 64 bits will be genera ted through some other procedure a nd combina tion of both pa rts will be used for the a pplica tion of encryption and decryption [38]. 4.2. steps of proposed genetic algorithm the genetic a lgorithm is ma inly consistin g of some tra ditiona l steps: initia l ra ndom popula tion genera tion, crossover, fitness function, a nd muta tion. although the procedure to perform these opera tions a re different in ea ch genetic a lgorithm but the ba sic steps a re the sa me in a ll ga. in the next section, we expla in the performa nce of each step of ga in deta il. 4.2.1. initial random population generation: as defined ea rlier tha t we a re genera ting the 128 bits key for the proposed cryptogra phic a lgorithm a nd 64 bits key will be genera ted through ga which mea ns we need to genera te 64 bits ra ndom numbers a s a n initia l popula tion a lso ca lled chromosomes in the genetic field. the process for genera ting the 64 bits bina ry ra ndom numbers is ba sed on linea r congrega tiona l procedure [39]. the deta il of this procedure will be given in section 2. 4.2.2. crossover procedure: after performing step one, a ll the newly genera ted chromosomes will go under the presses of crossover with the help of pseudora ndom number genera tor for 64 bits which will be discussed in 2.1, the resulta nt number obta ined from this procedure will decide a bout the crossover point. crossover is of severa l types one point, two points, three points, a nd ra ndom point therefore the resulta nt number will decide the ra ndom point for the crossover opera tion a nd is given by figure 2 in which the bits a fter the selected point will be excha nged by both pa rent chromosomes to get two new resulta nt species. fig. 2. ra ndomly selected one point cross over a nd excha nging the bits a fter 6 ra ndom point. 4.2.3. fitness function: the fitness of a ll newly genera ted chromosomes will be checked by using the fitness function. this procedure ca n reduce the number of popula tions by the surviva l of fitness which mea ns, only those species will exist which ha ve the best fitness a mongst a ll. the proposed fitness function for the proposed a lgorithm is given by eq. (1), 𝐹𝑖𝑡𝑛𝑒𝑠𝑠 𝐹𝑢𝑛𝑐𝑡𝑖𝑜 𝑛 = 1 − 𝑆𝐸𝐶 𝐺𝑎𝑝 𝑉𝑎𝑙𝑢𝑒 (1) where, sec = shannon entropy of chromosome in informa tion theory, entropy is a mea sure of the uncerta inty in a ra ndom va ria ble. about this, the term sha nnon entropy usua lly refers, to which qua ntifies the expected va lue of the informa tion conta ined in a messa ge (in cla ssica l informa tics it is mea sured in bits). sha nnon entropy a llowing to estima te the a vera ge minimum number of bits f. hanif (et al.), an energy efficient crypto suit for secure underwater sensor communication using genetic algorithm (pp. 01 17) sukkur iba journal of emerging technologies sjet | vol. 4 no. 2 july – december 2021 6 needed to encode a string of symbols ba sed on the a lpha bet size a nd the frequency of the symbols ca n be ca lcula ted by using the followin g formula , 𝐻 (𝑋) = − ∑ 𝑝(𝑥) log𝑏 𝑝(𝑥 𝑖 ) 𝑛 𝑖 =1 (2) in eq. (2) p(xi ) is the lower proba bility, i.e. p(xi )→0, the higher the uncerta inty or the surprise [40]. simila rly, the ga p test is performed to ca lcula te the ga p between two repea ting numbers [41]. the ga p test is used to determine the implica tion of the interva l between recurrences of the sa me digit. if the va lue of the a bove fitness function is close to 1 then it will be considered a s the fitted va lue a nd the threshold for the proposed a lgorithm is more tha n 89%. the most fitted va lue will be recorded a s the best. 4.2.4. mutation: the process of muta tion is helpful to a chieve globa l optima . all the chromosomes which a re grea ter tha n the threshold va lue in the la st procedure will go under the process of muta tion by a ga in using the ra ndom point muta tion procedure. the pseudora ndom number will genera te the ra ndom number a nd the bina ry bit will be flip of a ccording to the resulta nt ra ndom number to genera te a new chromosome a s given by figure 3. after a pplying muta tion on ea ch chromosome, we a ga in ca lcula te the fitness va lue of ea ch resulta nt by using (1) a nd select the best one a mong them if the ca lcula ted fitness va lue a fter muta tion is less tha n the previously recorded va lue then this process will be repea ted for 50 rounds till, we ha ve the more fitted va lue then the recorded one. if still we ha ve the chromosomes whose va lue is less tha n the previously recorded va lue, then the recorded va lue is considered a s fina l to become the better ha lf of the key. if the ca lcula ted fitness a fter muta tion is grea ter tha n the recorded va lues, then this va lue is considered a s the first ha lf of the key. the whole procedure to genera te the first ha lf of the key ca n be seen in the flow cha rt of figure 4. fig. 3. ra ndom point muta tion 4.3. linear congruential procedure for 64 bits binary number the a 64-bit linea r congruentia l genera tor (lcg) is defined by the following recursive formula , 𝑋𝑛 ≡ 𝑎𝑋𝑛 − 1(mod 𝑚), 𝑛 ≥ 1 (3) where m is the prime modulus, multiplier a a nd seed x0 a re between 1 a nd (m -1) for a 64-bit computer in eq. (3). the first bit of a signed integer is the sign bit, so the la rgest modulus presenta ble a s a n ordina ry integer is 263−1 for a 64-bit ma chine. three prerequisites for a n idea l lcg a re full period, ra n domness, a nd efficiency [42, 43]. the ma ximal period of a n lcg is m − 1, ca lled a full period lcg. an lcg is rela tively ea sy to implement and rea sona bly fast. to genera te a random number, it is importa nt to ha ve two pa ra meters of an lcg: multiplier a nd modulus. here we consider the 64-bit lcgs with prime modulus. three forms of prime modulus a re useful: mersenne prime modulus, sophie–germa in prime modulus, a nd la rgest prime modulus [44]. the distribution of mersenne primes is spa rse, so we ca n consider the la rgest mersenne number 261 − 1, denoted a s mp. there a re infinitely ma ny sophie–germa in primes. the la rgest sophie–germa in prime 263 − 4569 is chosen a nd is denoted a s sg. the la rgest prime modulus but not mersenne prime a nd sophie–germa in prime ones sma ller than 263 is 263 – 25, denoted a s lp. for a 64 -bit lcg, we pla ce the af or df restriction on the multiplier. since the number of multipliers is a stronomical, a n exhaustive sea rch a ppears to f. hanif (et al.), an energy efficient crypto suit for secure underwater sensor communication using genetic algorithm (pp. 01 17) sukkur iba journal of emerging technologies sjet | vol. 4 no. 2 july – december 2021 7 be impra ctica l. for porta bility a nd correctness, two types of restriction on multiplier a re distinguished: a pproxima te fa ctoring (af) multiplier a nd double-precision floa ting-point (df) multiplier [45]. fig. 4. the complete sequence of the proposed ga 4.4. pseudo-random number a pseudo-ra ndom number is a deterministica lly genera ted numbers that a ppea r to be ra ndom. to genera te these ra ndom numbers of va rious a rithmetic a pproa ches a re used, on computers in the pa st thirty yea rs or so. these a pproa ches a re usua lly recurrence rela tions a nd new numbers a re genera ted from the ea rlier one by a pplying some simple scra mbling opera tion. the most used method which is fa st a s well (or genera tor) is the so -ca lled multiplica tive congruentia l genera tor (sometimes a lso ca lled the power residue genera tor). it consists of computing xi+1 = xi a (mod m), where xi is a pseudo-ra ndom number, xi+1 is the next pseudo-ra ndom number, a is a constant multiplier a nd, modulo m mea ns tha t the number xi*a is divided by m repea tedly till the rema inder is less tha n m which is 64 in this ca se. the rema inder is then set equa l to the next number xi+1. the process is sta rted with a n initia l va lue xo ca lled seed [46]. in the proposed a lgorithm we perform the one-point crossover tha t performs a ccording to the ra ndom number genera ted by pseudo -random number a nd bit of tha t number ma rk as a crossover point a nd performs the one-point crossover a s given by the figure1. 4.4.1. summary of the 1st part of 64 bits key generation process: • initia lly genera te the ra ndom number of 64 bits by using the linea r congruentia l procedure. • first, genera te the pseudo-ra ndom number a nd obta ined a ra ndom number from 0 to 63 a s a crossover point, a nd perform the crossover opera tion. • apply the fitness test on ea ch genera ted number obta ined from step 1 with the f. hanif (et al.), an energy efficient crypto suit for secure underwater sensor communication using genetic algorithm (pp. 01 17) sukkur iba journal of emerging technologies sjet | vol. 4 no. 2 july – december 2021 8 help of eq (1) a nd stored the best va lue, which is grea ter or equa l to 0.89. • genera te the pseudo-ra ndom number and obta ined a ra ndom number from 0 to 63 a s a m uta tion point a nd perform a muta tion procedure. • aga in, ca lcula te the fitness va lue a nd compa re the best va lue with the stored va lue. if the stored va lue is less tha n the ca lcula ted va lue then stops, otherwise perform the a bove procedure until 50 rounds. if the ca lcula ted va lue is still less tha n the stored va lues, then fina lly stored va lues a re supposed to be the fina l 64 bits first pa rt of the key. 5. genetic algorithm as discussed ea rlier tha t in uwsns data will be sent through some fra mes a nd each fra me ha s different fields for different types of da ta informa tion. to a void a tta cks tha t may come in the form of a da ta fra me, an a uthentication code (ac) will be ca lcula ted by ea ch sensor to receive a ny da ta fra me. the sensor will open the incoming da ta frame after the verifica tion of ac, otherwise, it will be disca rded. this a uthentication code is going to be used in the ca lcula tion of the remaining part of the key. the steps of genera ting the a uthentication code a re a s follows, 1. ta ke the numeric pa rt of the sensor number a nd ma ke it squa re ta ke the mid-va lue 2. a nd the successive va lue a nd convert it into 32 bits bina ry va lues. 3. now consider the a lpha betic pa rt of sensor number a nd va lue and convert it into 32 bits bina ry form a nd ta ke the xor between the va lue obta ined from step i a nd ii. 4. after a pplying the xor the resulta nt is the a uthentication code for the incoming da ta fra me. 5.1. final key formation 1. merge the a uthentication code a nd the fra me number (which is numeric) of the incoming fra me a nd convert it into 32 bits bina ry form a nd fina lly, we obta ined the 64 bits va lue. 2. a combina tion of the first ha lf of the key which wa s genera ted through ga a nd the other ha lf va lue obta ined from step 1, is considered a s the 128 bits key for the proposed cryptogra phic suit for data communica tion in uwsns. 𝐹𝑖𝑛𝑎𝑙 𝐾𝑒𝑦 = 64 𝑏𝑖𝑡𝑠 𝑓𝑟𝑜𝑚 𝐺𝐴 + 𝐴𝐶 (𝐹𝑟𝑎𝑚 𝑒 𝑛𝑜 . ) (4) 5.2. algorithms for the encryption & decryption: the step-by-step deta iled encryption a nd decryption a lgorithm s used in the proposed solution a re represented below: algorithm for encryption start step 1: brea k the input text file into 128 bits. step 2: split it into four equa l pa rts of 32 bits. step 3: p1=1st pa rt a nd 3rd pa rt. p2 = 2nd pa rt a nd 4th pa rt. step 4: split 128 bits key into four equa l pa rts of 32 bits. step 5: k1 = 1st pa rt a nd 3rd pa rt a nd k2 = 2nd pa rt a nd 4th pa rt. encryption of p1 step 6: ta ke p1 convert a ll cha ra cters of input pla intext into its ascii. step 7: store a nd identify the minimum ascii va lue. f. hanif (et al.), an energy efficient crypto suit for secure underwater sensor communication using genetic algorithm (pp. 01 17) sukkur iba journal of emerging technologies sjet | vol. 4 no. 2 july – december 2021 9 step 8: perform the modulus opera tion on ea ch character value by using the minimum ascii va lue. step 9: perform xor with k 1 = d1 step 10: find ba se 64 va lue of k 1 step 11: pick 8 a lpha bets = b1 (16 cha ra cters), use it a s the first row of ma trix write 128 bits of d1 in the form of the column below ea ch a lpha bet. step 12: apply the shifting of column (store the a rra ngement of b1 a fter column shifting) = r 1 . step 13: aga in a pply the shifting of rows by writing b1 a s the first column a nd the set of new va lues of r 1to be fix a s a row corresponding to ea ch a lpha bet of key the column (store the a rra ngement of b1 a fter row shifting) = e1. step 14: apply [bit xor [(mod k1+e1 ,64)]] convert it into for ascii va lues. step 15: encrypted text of p1 . encryption of p2 step 16: p1 ta kes the tra nspose of p1 xor k2. step 17: applying left rota tion by 5. step 18: add k2 in the resulta nt. step 19: apply right rota tion by 3 step 20: a dd key in the resulta nt. step 21: apply 2’s compliment. step 22: convert it into ascii va lues. step 23: encrypted text of p2. end algorithm for decryption start decryption of p1 step 1: ciphertext c1 step 2: apply xor with . step 3: ca lcula te the reverse of mod 64 a nd subtra ct with k 1 . step 4: by using the stored a rra ngement of b1 a fter shifting of rows, perform rea rra ngement of rows till getting the a ctua l a rra ngement of b1 (a ccording to ba se 64). step 5: by using the stored va lue of b1 a fter column shifting, rea rra nge the columns till getting the a ctua l va lue of k 1 (a ccording to ba se 64). step 6: perform xor with 64 bits key. step 7: perform the reverse mod opera tion a ccording to the stored ascii minimum va lue to get the origina l text p1 . f. hanif (et al.), an energy efficient crypto suit for secure underwater sensor communication using genetic algorithm (pp. 01 17) sukkur iba journal of emerging technologies sjet | vol. 4 no. 2 july – december 2021 10 decryption of p2 step 8: ta ke the ascii va lues equiva lent to ciphertext c 2. step 9: apply 2’complement. step 10: subtra ct k2. step 11: apply left rota tion by 3. step 12: subtra ct k2. step 13: apply right rota tion by 5. step 14: ta ke xor with k2. step 15: obta ined origina l text p2. final text step 16: split 64 bits of p1 into two pa rts. step 17: p1=1st pa rt a nd 3rd pa rt a nd p2 = 2nd pa rt a nd 4th pa rt. step 18: merge a ll pa rts a ccording to the sequence. step 19: the resulta nt 128 bits is the origina l pla in text. end 6. results and analysis this section provides the results a nd a na lysis of the performa nce of the proposed a lgorithm. the eva lua tion ca n be done ba sed on the ma in fea tures of a ny existing cryptogra phic a lgorithm. the deta ils of our eva lua tion will show how the proposed a lgorithm ma inta ins its security while implemented. fig. 5(a). avera ge running time for encryption procedure by different algorithms fig. 5(b). avera ge running time for decryption procedure by different algorithms f. hanif (et al.), an energy efficient crypto suit for secure underwater sensor communication using genetic algorithm (pp. 01 17) sukkur iba journal of emerging technologies sjet | vol. 4 no. 2 july – december 2021 11 fig. 5(c). avera ge throughput for encryption procedure by different algorithms fig. 5(d). avera ge throughput for decryption procedure by different algorithms 6.1. equations elitism criteria in ga we ha ve genera ted our key through the genetic a lgorithm a nd while genera ting the ra ndom number for a key genera tion we have used the concept of elitism in our coding which enha nces the selection criteria for a ny genera ted chromosomes. it is importa nt to ma inta in a dequate selection pressure, as dema nded by the a pplica tion, to a void genetic drift. elitism ca n increa se the selection pressure by preventing the loss of low “sa lience” genes of chromosomes due to deficient selection pressure; it improves the performa nce of optimality a nd convergence of gas in ma ny ca ses. elitism provides a means for reducing genetic drift by ensuring tha t the best chromosome(s) is a llowed to pa ss/copy their tra its to the next genera tion [47]. 6.2. system environment the proposed a lgorithm wa s implemented in matlab a nd the compa rison ha s been eva lua ted a gainst some benchmark symmetric encryption a lgorithms like 3 des, mars, rivest cipher (rc6), da ta encryption algorithm (des), below fish, a nd aes in terms of running time, throughput for encryption a nd decryption a long with the a va la nche effect a nd spa ce usa ge [47]. the da ta which is used in our experiments a re rea l da ta that has been used between sensor communica tion a nd the proposed a lgorithm ha s been tested for different file size which is ra ndomly ta ken between some interva ls of [1k-1m], [1m-100m], [100m-500m], [500m-1 g] a nd [1g-5g]. the a im is to show tha t the performa nce of the proposed a lgorithm in terms of a ll the a bove-mentioned fea tures is better tha n the existing a lgorithms which a re supposed to be th e benchmark techniques. the indica ted results a re ba sed on a vera ge va lues beca use ea ch test wa s conducted severa l times. the cryptogra phic a lgorithm sta rts with the process of key genera tion. 6.3. performance analysis here we discuss our implementa tion and results in terms of performa nce for security fea tures like throughput, processing time, and the a va la nche effect. figure 5 (a ), 5(b) is showing the a verage running time of encryption a nd decryption procedure for the proposed a lgorithm together with other benchma rk procedures for different input file sizes a s mentioned a bove. the running time is ma inly the time ta ken by any f. hanif (et al.), an energy efficient crypto suit for secure underwater sensor communication using genetic algorithm (pp. 01 17) sukkur iba journal of emerging technologies sjet | vol. 4 no. 2 july – december 2021 12 a lgorithm to encrypt/ decrypt a ny pla in text into ciphertext. according to the figure it can be seen tha t the proposed a lgorithm has a better performa nce in terms of running time for encryption a nd decryption. after this, we eva lua te our ga ba sed method for the throughput of the encryption/decryption procedure. throughput in (bytes/sec) ca n be define by using the following formula given in (5), 𝑇ℎ𝑟𝑜𝑢𝑔ℎ𝑝𝑢𝑡 = ∑ 𝐼𝑛𝑝𝑢𝑡 𝐹𝑖𝑙𝑒 𝑆𝑖𝑧𝑒 ∑ 𝐸𝑥𝑒𝑐𝑢𝑡𝑖𝑜 𝑛 𝑇𝑖𝑚𝑒 (5) figure 5(c), 5(d) showing the a vera ge throughput for the encryption a nd decryption for the proposed a lgorithm, a nd a s compa red to other techniques it ca n be ea sily seen that our a lgorithm ha s better throughput for ra ndom file sizes. 6.4. energy consumption and network lifetime ba la ncing the energy is not a n ea sy ta sk in underwa ter sensor networks. a ba la nced network is one in which the rema ining a mount of energy is the sa me in the end, which means tha t ea ch node does not die before others. sensors ba la nce their energies by sha rin g the duties which need a n extra a mount of energy. in underwa ter sensor networks, the initia l energy of ea ch sensor node is the sa me, but in the proposed technique the energy consumption of ea ch sensor is a lmost identical a fter the tra nsmission process. since in the provided a lgorithm the sensors a re in sleep mode before receiving a nd a fter tra nsmitting the da ta to the ba se sta tion in ea ch round. during the execution of the proposed method energy of ea ch sensor a fter 100 rounds is a lmost the sa me. but a fter 500 rounds of ga, it is evident tha t the energy of some sensors is a lmost the sa me, a nd some have fluctua ted a t the end of the network lifetime. from ta ble 1 the mea n a nd sta ndard devia tion of the rema ining energy of sensor nodes which mea ns tha t the energy va ria tion of a ll sensors is a lmost the sa me. table 1: the mea n a nd sta ndard devia tion of the rema ining energy for three simula tion runs rounds 100 300 500 mea n 0.38 0.29 0.24 s. d 0.009 0.013 0.025 fig. 6(a). sensor’s energy level a fter 100 rounds. fig. 6(b). sensor’s energy level a fter 500 rounds. 6.5. security analysis this section will discuss the eva lua tion of our proposed a lgorithm on the ba sis of the security purpose which is known a s a va lanche effect. the a va la nche effect is mea suring the strength of the a lgorithm for ha cking and cra cking threa ts. rea l-time threa ts such as brute force a tta cks ca n be mea sured by a va la nche effects, a nd it requires the number of bits tha t ha ve been cha nged during the process of encryption from pla in text to ciphertext. ava la nche effect ca n be ca lculated by using the formula , f. hanif (et al.), an energy efficient crypto suit for secure underwater sensor communication using genetic algorithm (pp. 01 17) sukkur iba journal of emerging technologies sjet | vol. 4 no. 2 july – december 2021 13 𝐴𝑣𝑎𝑙𝑎𝑛𝑐ℎ𝑒 𝑒𝑓𝑓𝑒𝑐𝑡 = 𝑁𝐹𝐵𝐶𝑇 𝑁𝐵𝐶𝑇 x 100% (6) where, nfbct = no. of flipping bits in the ciphertext nbct = no. of bits in the ciphertext according to figure 7 aes is the only a lgorithm tha t ca n ma na ge a high a va lanche effect a s compa red to other benchmark a lgorithms. but proposed the a lgorithm shows the highest a va la nche effect in compa rison to aes a nd off course rest of the other encryption techniques. fig. 7. ava la nche effect of different a lgorithms in terms of % fig. 8. spa ce usa ge of different a lgorithms (in bytes) 7. security evaluation as expla ined ea rlier, uwsns possess a limited ba ttery with very low spa ce a nd lots of security issues. the results from the proposed eva lua tion ca n conclude tha t the presented a lgorithm produced the lowest running possessing time, highest throughput, and highest a va la nche effect, a nd this ma de our proposed a lgorithm fa st, secure, efficient, and relia ble. in this section, we a na lyze the security of the proposed a lgorithm a ga inst va rious a ttacks rela ted to underwa ter sensor networks. for providing secure cryptogra phic a lgorithms, it is importa nt to ta ke ca re of different kinds of a tta cks tha t might occur while tra nsferring the da ta between the nodes. 7.1. plain text attack: considered the most ba sic a tta ck on the cryptogra phic a lgorithms, this a tta ck a rises when an a tta cker tries to a tta ck both pla in text a nd ciphertext. this a tta ck works during the da ta tra nsmission for encryption a nd sna tches the chunks of pla in text. since it is difficult to the get key, therefore, a tta ckers try to genera te the method of encryption with the help of some portion of the pla in text a nd ciphertext. la ter it is used for the decryption of ciphertext. in the proposed technique the pla in text is not tra nsmitted within the sensor nodes only cipher text is sent. so it is impossible tha t this a tta ck ca n occur be-ca use if the a tta cker ca n a ble to ca pture some portion of the ciphertext then it is impossible for the a tta cker to get the key a s the key is upda ted in every round a nd the cipher-text a lso cha nges in ea ch round. 7.2. ciphertext attack: a very common a tta ck ca lled ciphertext a tta ck in which a n a tta cker ca n only be a ble to a ccess some portion of ciphertexts. this a ttack could be very da ngerous if corresponding pla in text is extra cted or even more ha rmful if the key ca n be deduced. this a tta ck could ea sily occur if the ciphertext is sent through the network but, in the propose technique, the ciphertext is divided into four pa rts, a nd encryption is implemented piecewise on the pla in text, which ma kes it a lmost impossible for tha t this f. hanif (et al.), an energy efficient crypto suit for secure underwater sensor communication using genetic algorithm (pp. 01 17) sukkur iba journal of emerging technologies sjet | vol. 4 no. 2 july – december 2021 14 a tta ck to oc-cur. also, in the proposed technique the key does not directly send over the network. it will be ca lcula ted on the end of the da ta receiving senor by using some informa tion given by the network which is not complete. therefore, without the informa tion of key, it is difficult for the ciphertext to be decrypted by using the proposed technique. 7.3. related-key attack: this a tta ck can occur in a ny form of crypta na lysis in which the a tta cker tries to pick the opera tion of cipher by using different keys tha t a re initia lly not completely known to a ccept some ma thematical opera tions rela ted to key a re known. for exa mple, if the a tta cker got some informa tion tha t the la st 80 bits of the keys a re a lwa ys the sa me a s ha ving the informa tion a bout the a ctual bits. but in the proposed technique the key is not a lwa ys the sa me some ea ch text. as per the key genera tion procedure which is ca lcula ted on the ba sis of sensor number a nd ra ndomly genera ted id a t ea ch round therefore it is not possible tha t this a tta ck will occur for the proposed technique. as the key is genera ted by using ra ndomly genera ted pa ra meters which ma ke this a tta ck impossible to occur by using this technique. 7.4. man in the middle attack (mim): the proposed technique is highly vulnera ble to this a tta ck, beca use of the two rea sons, the proposed technique is ba sed on the ra ndomly genera ted pa ra meters. secondly, the proposed technique genera tes the ha sh function for the a uthentica tion code tha t is why this a tta ck becomes the mea ningless for the proposed technique. three people have involved in this a tta ck: the victim, the a tta cker, a nd the person to which the victim tries to communica te. this a ttack tries to a ccess the secret pa ra meter va lues, but due to the involvement of a uthentica tion code which will be verified by sender a nd receiver, that ma kes this a tta ck wea ker for the proposed technique. this a tta ck is possible if the a t-ta cker tries to hea r the conversa tion between the sender a nd receiver, but for the pro-posed a lgorithm if this ha ppened then the da ta will be decrypted by using the key. as defined ea rlier the key does not send over the network it will be ca lcula ted by the receiving sensor tha t is why ma n in the middle a tta ck is helpless a s it ca n’t get the key. 7.5. hello flood attack: this a tta ck sends hello pa ckets in order to consume network resources. but in the proposed technique the receiving senor does not receive a ny pa ckets without an a uthentica tion code, therefore the proposed technique is immune to this a tta ck. 7.6. dos attack: this a tta ck utilizes the network ba ndwidth by sending a dvisory pa ckets which pre-vent the user from utilizing the services a nd resources. this a tta ck usually occurs on the cluster head of the network. the proposed methodology overcomes this a tta ck by sending the a cknowledgment messa ge by the ba se sta tion. 7.7. compromise cluster head attack : this a tta ck tries to get a ll the informa tion from the cluster nodes by ma king them believe tha t it is workin g a s a cluster hea d. the ma in ta sk of this a tta ck is to extra ct the ba sic informa tion from the da ta . in our proposed technique the cluster hea d sends the da ta from the nodes without decrypting it, a lso in the proposed technique encryption is depending on ma ny pa ra meters such as sensor number, a uthentica tion code, ra ndomly genera ted numbers a t ea ch f. hanif (et al.), an energy efficient crypto suit for secure underwater sensor communication using genetic algorithm (pp. 01 17) sukkur iba journal of emerging technologies sjet | vol. 4 no. 2 july – december 2021 15 round. to encrypt the da ta the a ttacker, must know the complete informa tion a bout a ll the opera tions a long with the secret bina ry string which is genera ted by the key genera tion procedure. therefore, due to a ll a bove-mentioned fa c-tors, we ca n ea sily sa y tha t for the proposed technique this a tta ck is not possible to occur. 8. conclusion this study ha s intended to provide the secure crypto ba se encryption a lgorithm (ga) for the communica tion between underwa ter sensors. the proposed a lgorithm ca n be a b le to genera te the first ha lf portion of the key by using a genetic a lgorithm tha t is ba sed on 32 bits, a fter tha t, it ca lcula tes the a uthentica tion code for the fina l key genera tion of 128 bits. in ga a fitness function ha s been introduced with the pa ra meters tha t helped in the identifica tion of the best chromosomes a mong the ra ndom popula tion. by the help of ga steps first pa rt of the key will be genera ted and the rema ining pa rt will be genera ted by some different procedure. furthermore, there a re two sepa ra te procedures of encryption a lso, with the idea to ma ke encryption procedure trickier without involving complex steps to a void the computa tional complexities. overa ll procedure ha s been designed in a way tha t ca n be a ble to a void different threa ts which a re very obvious in underwa ter communica tion. an a uthentica tion code has been used to protect the da ta from pa ssive a tta cks. the compa rison ha s been implemented with other benchmark symmetric encryption techniques to show the efficiency of the proposed cryptogra phic a lgorithm in terms of running processing time, throughput, a nd the a va la nche effect. the rea son behind using the ga technique is due to its ra ndomness. ga is a ra ndom procedure, a nd it ma kes key guessing a lmost impossible. the novelty of the proposed work is tha t ga ha s never been involved in underwa ter secure communica tion. this study ha s proved that with the help of ga a nd the present -ed encryption procedure we ca n efficiently be done the secure communica tion between underwa ter sensors a nd security ca n be made even better by the implementa tion of the proposed a lgorithm. 9. future works future work includes inclusion of lightweight methods for a dditiona l protection from new a nd evolving types of a tta cks. the a va ila bility of improved computa tional a nd energy-sufficient sensors will a lso a llow the inclusion of complex a lgorithms a nd encryption-decryption techniques to further secure the underwa ter senor networks. references [1] y. xuanxia, z. chen, and y. tian. "a lightweight attribute-based encryption scheme for the internet of things." future generation computer systems vol. 49, pp. 104-112, 2015 [2] d. gianluca, and a. l. duca. "a secure communication suite for underwater acoustic sensor networks." sensors, vol. 12, no. 11, pp 1 513315158, 2012. [3] s. kotari, and mb. m. krishnan. (2018, august), "improvisation of underwater wireless sensor network’s efficiency for secure communication." iop conference series: materials science and engineering. vol. 402. no. 1. [4] c. angelo et al. (2017 , november), "securing underwater communications: key agreement based on fully hashed mqv." proceedings of the international conference on underwater networks & systems. pp. 1-5. [5] r. g. nitinkumar, and b. r. kaur. "a new approach for data encryption using genetic algorithms and brain mu waves.", international journal of scientific and engineering research, vol. 2, no. 5, may, 2011. [6] a. faiyaz, s. khalid, and m. s. hussain. "encrypting data using the features of memetic algorithm and cryptography." international journal of pattern recognition and artificial intelligence, vol, 2, no. 3, pp.109-110, june, 2011 [7] m. swati, and s. bali. "public key cryptography using genetic algorithm." international journal of recent technology and engineering vol. 2, no.2, pp. 150-154, may, 2013. [8] deng, lih-yuan, henry horng-shing lu, and taibeen chen. "64-bit and 128-bit dx random number f. hanif (et al.), an energy efficient crypto suit for secure underwater sensor communication using genetic algorithm (pp. 01 17) sukkur iba journal of emerging technologies sjet | vol. 4 no. 2 july – december 2021 16 generators." computing, vol.89, no1 -2 pp.27-43, august, 2010. [9] j. sania, and a. jamal. "generating the best fit key in cryptography using genetic algorithm." international journal of computer applications, vol.98, no.20, pp.33-39, july, 2014. [10] g. s. fishman, "random tours." monte carlo. springer, new york, ny, 1996. [11] k, donald. "seminumerical algorithms." the art of computer programming 2, 1981. [12] p. srikanth, et al. "encryption and decryption using genetic algorithm operations and pseudorandom number." computer science and network, vol.6, no.3, pp.455-459, 2017. [13] t. hui-chin, and h. chang. "an exhaustive search for good 64-bit linear congruential random number generators with restricted multiplier." computer physics communications vol.182, no.11, pp.23262330, november, 2011. [14] m. p. more, and p. g. naik. "hybrid security framework for activity based authentication using rsa & genetic algorithm." international journal on recent and innovation trends in computing and communication, vol.3, no.11, pp.6175-6184, november, 2015. [15] d. dumitru, et al. evolutionary computation. crc press, 2000. [16] p. m. reed, b. s. minsker, d. e. goldberg. “the practitioner's role in competent search and optimization using genetic algorithms”, in bridging the gap: meeting the world's water and environmental resources challenges pp. 1 -9, 2001. [17] a. shadi, and m. b. yassein. "a resource-efficient encryption algorithm for multimedia big data." multimedia tools and applications, vol. 76, no.21, pp.22703-22724, 2017. [18] n. m. irshad, et al. "implication of genetic algorithm in cryptography to enhance security." int. j. adv. comput. sci. application, vol.9, no.6, pp.375-379, june, 2018. [19] s. dutta, et al. "a cryptography algorithm using the operations of genetic algorithm & pseudo random sequence generating functions." international journal of advances in computer science and technology, vol.3, no.5, may, 2014. [20] delman, bethany. "genetic algorithms in cryptography." [ms. thesis]. rochester institute of technology, rochester, new york, 2014. [21] s. goyat. "genetic key generation for public key cryptography." international journal of soft computing and engineering (ijsce), vol. 2, no. 3,pp. 231-233, july, 2012. [22] c. peng,et al. “an ultra-lightweight encryption scheme in underwater acoustic networks” journal of sensors, vol.2016, february, 2016. [23] m. baykara, et al. "a novel symmetric encryption algorithm and its implementation." fırat university turkish journal o f science and technology, vol. 12, no.1, pp.5 -9, 2017. [24] g. han, et al. "secure communication for underwater acoustic sensor networks." ieee communications magazine, vol. 53, no.8, pp. 5460, august, 2015. [25] r. jhingran, v. thada, and s. dhaka. "a study on cryptography using genetic algorithm." international journal of computer applications, vol.118, no.20, pp.10-14, january, 2015. [26] m. jouhari et al. “underwater wireless sensor networks: a survey on enabling technologies, localization protocols, and internet of underwater things”. ieee access, vol. 7, pp.96879-96899, july 2019. [27] m. khalid et al. "a survey of routing issues and associated protocols in underwater wireless sensor networks." journal of sensors, vol .2017, 22, may, 2017. [28] j. e. kim et al. "security in u nderwater acoustic sensor network: focus on suitable encryption mechanisms." asian simulation conference. springer, berlin, heidelberg, pp. 160 -168, 27, october, 2012. [29] a. kumar, and c. kakali. "an efficient stream cipher using genetic algorithm." 2016 international conference on wireless communications, signal processing and networking (wispnet). ieee, pp. 2322-2326, 23, march, 2016. [30] a. kumar and m. k. ghose. "overview of information security using genetic algorithm and chaos." information security journal: a global perspective, vol.18, no.6, pp.306-315, 9, december, 2009. [31] c. lal et al. "toward the development of secure underwater acoustic networks." ieee journal of oceanic engineering, vol. 42, no.4, pp.1075-1087, 6, july, 2017. [32] y. liu, j. jing, and j. yang. "secure underwater acoustic communication based on a robust key generation scheme." 2008 9th international conference on signal processing. ieee, pp. 18381841, 26, october, 2008. [33] g. ateniese, et al. "secfun: security framework for underwater acoustic sensor networks." oceans 2015-genova. ieee, pp. 1-9, 18, may, 2015. [34] s. moffat, m. hammoudeh, and r. hegarty. "a survey on ciphertext-policy attribute-based encryption (cp-abe) approaches to data security f. hanif (et al.), an energy efficient crypto suit for secure underwater sensor communication using genetic algorithm (pp. 01 17) sukkur iba journal of emerging technologies sjet | vol. 4 no. 2 july – december 2021 17 on mobile devices and its application to iot." in proceedings of the international conference on future networks and distributed systems. 19, july, 2017. [35] d. pompili, and i. f. akyildiz. "overview of networking protocols for underwater wireless communications." ieee communications magazine, vol.47, no.1, pp.97-102, 10, february, 2009. [36] g. r. s. qaid and s. n. talbar. "bit-level encryption and decryption of images using genetic algorithm: a new approach." ipasj international journal of information technology (iijit) 1.6 (2013). [37] m. stojanovic, "underwater wireless communications: current achievements and research challenges." ieee oceanic engineering society newsletter, vol. 41, no.2, pp. 1 -5, november, 2006. [38] s. y. tan, k. w. yeow, and s. o. hwang. "enhancement of a lightweight attribute-based encryption scheme for the internet of things." ieee internet of things journal, vol. 6, no.4, pp.63846395, 25, february, 2019. [39] yang, guang, et al. "challenges and security issues in underwater wireless sensor networks." procedia computer science, vol. 147 , pp.210-216, 1, january, 2019. [40] g. yang, l. dai, and z wei. "challenges, threats, security issues and new trends of underwater wireless sensor networks." sensors, vol.18, no.11, pp.3907, november, 2018. [41] k. m. awan, et al. "underwater wireless sensor networks: a review of recent issues and challenges." wireless communications and mobile computing, vol.2019, 1, january,2019. [42] y. cong, et al. "security in underwater sensor network." 2010 international conference on communications and mobile computing. vol. 1, pp. 162-168, ieee, 12, april, 2010. [43] m. c. domingo, "overview of channel models for underwater wireless communication networks." physical communication, vol. 1, no.3, pp.163-182, 1, september, 2008. [44] r. ebrahimzadeh and m. jampour. "chaotic genetic algorithm based on lorenz chaotic system for optimization problems." international journal of intelligent systems and applications, vol. 5, no.5, pp.19, 1, april, 2013. [45] c. m. g. gussen, et al. "a survey of underwater wireless communication technologies." j. commun. inf. sys, vol.31, no.1, pp. 242-255, 27, october, 2016. [46] i. f. akyildiz, d. pompili, and t. melodia. "challenges for efficient communication in underwater acoustic sensor networks." acm sigbed review, vol. 1, no.2, pp.3-8, 1, july, 2004. [47] p. sritha, et al. "a new modified rc6 algorithm for cryptographic applications." int. j. adv. res. comput. commun. eng, vol. 3, no.12, pp.22781021, december, 2014. vol. 1, no. 2 | july december 2018 sjet | issn: 2616-7069 | vol. 1 | no. 2 | © 2018 sukkur iba 52 a smart on-grid solar charge controller abdullah1, ghulam murtaza1, saad arain1 , farhanullah sarki1 abstract: the theme of this project is to design a hybrid system which harnesses electricity from renewable source that is the sun using photo-voltaic solar panels as long as the sun is available to charge batteries and operate load and when it is not available for example at night or in cloudy weather or in the rain the charging of batteries is switched from sun to the other alternative source such as ups (uninterrupted power supply) or through ac source.ac source of 220v in the project is given through ac source. this project focuses on utilization of renewable source of energy. ofcourse the energy from sun varies along the day which varies the energy generated from it. so to protect our batteries from being overcharged or fully-discharged we have designed a charge controller which determines the battery’s soc (state of charge) and determines whether to charge it from solar or the alternative source if provide by us. this hybrid system aims to keep our batteries often running and that in the healthy condition [1]. 1. introduction the untenable nature of fossil fuels and its appalling effect onto environment create concerns for an environmental friendly alternative energy source as fossil fuel dependence increases exponentially. fossil-fuels are motive for greenhouse emissions, incompetent use of energy and deliverance of harmful contaminant to the atmosphere we realized usage of renewable energy sources concerning the safety of our environment. due to expensive prices and declining of fossil fuel, we are introducing charging mechanism for solar powered vehicle. also, solar energy is clean and green source among all renewable sources because it provides 3.8 x 1026 joules/day, low maintenance cost, also researcher focus on new techniques with innovative ideas on 1 department of electrical engineering, sukkur iba university corresponding email: abdullah.be14@iba-suk.edu.pk solar energy that’s why its efficiency improves day by day, if we review today’s market solar energy is fastest alternative for standalone system. we are implementing this technology because of its improvement in efficiency, growth and effectiveness. application area of our project that it can be used as hybrid charging of battery. we can use charge controller as grid connected especially it is best for villagers where there is load shedding of about 20/24h, one cannot survive without electricity, that’s why we have proposed a charge controller which is charged by using national grid supply as well as solar. our charge controller charges the battery with 20a and 24v whenever voltages of solar reduced below the 20v automatically wapda supply charges the battery by triggering relay 2 and our pwm mailto:abdullah.be14@iba-suk.edu.pk abdullah (et-al), a smart on-grid solar charge controller (pp. 52-59) sukkur iba journal of emerging technologies sjet | volume 1 no. 2 july – december 2018 © sukkur iba university 53 charge controller prevents the battery from overcharging. over discharging and reverse power flow, and charge our battery smoothly hence the life time of battery is increased and continue to supply our loads [2]. 2. charge controller as the output of solar is varying and fluctuated because the energy and direction of sun is always changing at every second or due to bad weather, the electrical desired values for battery charging are not achieved. so we need here charge controller which also prevents battery from over-charging, over discharging and reverse battery control [3]. functions of charge controller functions of charge controller are defined below.  prevention from overcharging: transistors are used to limit the amperes if battery is charged.  prevention from over discharging: cutoff the supply if voltage of battery falls down threshold level.  blockage from reverse charging: diode are used as reverse bias for prevention of reverse voltages towards solar side.  control-functions: timer is used to control the load connection and disconnections. 3. types of charge controller there are basically two types of charge controller pwm & mppt, now a days these two methods are mostly used in offgrid system, the decision to use any of the above has not depend on power output, but it depends on the design of system and as well as weather conditions. if we want to differentiate between these two controllers, power curves is best. it shows the power generation based on potential difference and current [4]. pwm charge controller pwm activates when battery is almost fully charged. when the controller supplies voltage to battery until panel voltages equals to battery voltage and there is direct connection between panel and battery. when the battery and panel voltages are equals, controller disconnects the pv and battery, and battery voltage is constant this fast-connecting method is called as shown in figure 1. fig 1: pwm charge controller battery is protected by overcharging, it works slightly above the maximum power point of solar panels as shown in figure 2. fig 2: power curve for pwm controller abdullah (et-al), a smart on-grid solar charge controller (pp. 52-59) sukkur iba journal of emerging technologies sjet | volume 1 no. 2 july – december 2018 © sukkur iba university 54 mppt charge controller this controller has unintended link between solar panels and battery, unintended link consists of dc-dc converter that actually gets solar voltage and converts it into current and reducing voltages where power is not affected, block diagram is shown in figure 3. fig 3: mppt charge controller the power curve for maximum power transfer is shown in figure 4 below. fig 4: power curve for pwm charge controller difference between both controllers we are going to select a suitable charge controller on the basis of cost, efficiency, complexity, availability. that is why we understand the difference between charge controllers in below table i. table i: difference between both controllers two way on-grid solar charge controller charge controllers are designed to control the device voltage and open the circuit, halting the charging when the battery voltage is supposed to reach a certain level. most of the charge controller uses mechanical relays to make or break the circuit of device and battery. the charge controller that we have designed is on the method, which continuously monitors the battery voltage, and based on that monitoring it charges the battery through solar panel voltages. it is also known as hybrid charge controller because it keeps on charging the battery even when solar panel voltages reaches below a certain limit. that is done through main 220v wapda source. during day time when solar panel voltage goes above 20v the controller switches to charging of battery through solar sources, and during night or due to unconditional weather when solar panel voltage goes below 20v, the controller switches to main wapda source for the charging of battery. pwm mppt cost efficient almost half of mppt expensive longer lifespan because of complex circuit lifespan is less because of electronic circuit less thermal stress high thermal stress smaller size bulky size used for 150200w power system used above 200w design pv array sized on voltage basis pv array is sized on basis of power abdullah (et-al), a smart on-grid solar charge controller (pp. 52-59) sukkur iba journal of emerging technologies sjet | volume 1 no. 2 july – december 2018 © sukkur iba university 55 4. experiment our experiment goes through four stages.  solar panel  charge controller  batteries  load solar panel solar pv cells consist of silicon or particular types of semiconductor materials which converts the solar energy into dc electricity. batteries are required to store energy for use in emergency and night time. a pv or solar energy system, is consisted of solar cells. these cells are connected in series and parallel to provide required current and voltage which in turns forms pv module. likely these modules are connected in parallel and in series making a network of modules to produce the desired current and voltage. however, the pv output current and voltage is dependent on ambient temperature and irradiance hence (i-v) characteristics of pv module changed nonlinearly in accordance with change in irradiance and temperature. commonly, there is a special point on the currentvoltage i-v or power-voltage p-v curve of a photovoltaic array where the output power of module has maximum value. in order to get maximum power from the array, it must be operated constantly at this maximum power factor (mpp). due to the nature of the photovoltaic system, the maximum output power varies with the variation in solar radiation and climate conditions, mainly the temperature. the position of the mpp on the i-v curve of the module is not always acknowledge, so it needs to be decided either through calculation methods or with the help of any search method and algorithm [6]. pv module is modelled in matlab simulink by modelling standard equations and equations are given below. i= iph id ish (1) id=is [exp (vd/vt)-1] (2) ish= v+irs rsh (3) iph= [ ish + ksc*(tc – to )* ( 𝐺 𝐺𝑠 ) ] (4) now module current equation become i= iph is [exp (vd/vt)-1] v+irs rsh (5) all these equations were modeled in simulink and resultant model will become as show in figure 5. fig 5: presentation of whole pv module fig 6: grouped subsystem of pv module analysis of pv model the model has been run under different ambient condition by changing temperature and irradiance as the input to the model to observe the i-v and p-v characteristics of abdullah (et-al), a smart on-grid solar charge controller (pp. 52-59) sukkur iba journal of emerging technologies sjet | volume 1 no. 2 july – december 2018 © sukkur iba university 56 the panel. when we vary the temperature, the irradiance is kept constant and vice versa. the module data used is shown in table ii. table ii: module data effect of variation of irradiance here as the irradiance increases, short circuit current also increases along with the open circuit voltage. because of both increasing of v and i, the pmax also increases according the irradiance. i-v characteristics under varying irradiance are shown in figure 7 and 8. fig 7: i-v characteristics under varying irradiance fig 8: p-v characteristics under varying irradiance effect of variation of temperature the simulation is run under the condition of variable temperature and constant irradiance. the open circuit voltage falls as temperature increases, but the short circuit current is less in high temperature. the maximum power point is also inversely proportional to the temperature. i-v characteristics under varying temperature are shown in figure 9 and 10. fig 9: i-v characteristics under varying temperature abdullah (et-al), a smart on-grid solar charge controller (pp. 52-59) sukkur iba journal of emerging technologies sjet | volume 1 no. 2 july – december 2018 © sukkur iba university 57 fig 10: p-v characteristics under varying temperature charge controller charge controllers are designed to control the device voltage and open the circuit, halting the charging when the battery voltage is supposed to reach a certain level. most of the charge controller uses mechanical relays to make or break the circuit of device and battery. the charge controller that we have designed is on the method, which continuously monitors the battery voltage, and based on that monitoring it charges the battery through solar panel voltages. it is also known as hybrid charge controller because it keeps on charging the battery even when solar panel voltages reaches below a certain limit. that is done through main 220v wapda source, during day time when solar panel voltage goes above 20v the controller switches to charging of battery through solar sources, and during night or due to unconditional weather when solar panel voltage goes below 20v the controller switches to main wapda source for the charging of battery. batteries the main theme of the battery is to convert chemical energy to electrical energy and vice versa. it is two terminal devices: a positive (anode) and negative (cathode), voltage difference depends upon the chemical reaction of the electrolyte, this battery may be used to store the charges or used as power supply for the loads. we used lead acid battery in our project due to its prominent feature ad advantages [7]. lead acid battery in this battery, chemical reaction takes place between electrolyte of h2so4 and h2o, this is earliest battery, a separator is used between these two electrolytes. when load is connected to this battery, sulphate ions are bonded with sheet and sulphuric acid discharge from battery as shown in shown as figure 11. fig 11: lead acid battery load for testing load we used two 12v dc fans connected with the battery as shown in figure 12. fig 12: dc fans (as a loads) abdullah (et-al), a smart on-grid solar charge controller (pp. 52-59) sukkur iba journal of emerging technologies sjet | volume 1 no. 2 july – december 2018 © sukkur iba university 58 5. results we are taking the results of hardware step-by-step first connecting whole setup, all the results will display on the lcd and lcd provides us user friendly information. fig 13: connection of battery with system is displayed in order to charge batteries, we connect our batteries with charge controller, and when batteries will be connected the lcd will display the capacity of system i-e 24v and 20a. if required voltage is being supplied from panels, charge controller will start to charge the batteries as shown in figure 14. in case weather is much cloudy or it is night time, then controller will switch to alternative 20v supply and continue to charge batteries as shown in figure 15. fig 14: batteries charges from solar fig 15: charging of battery through ac source figure 16 shows the whole circuit of solar charge controller which is being designed in this work of research. fig 16: solar charge controller 6. conclusion the efficiency and the performance of renewable-energy sources can be harnessed further by the development of the maximum power point tracking and the battery charging control techniques. the proposed hybrid charge controller will be reliable and will accurately charge batteries through solar panel via sun light in day time and also charge batteries through any a.c supply in night time or in cloudy days. so we can use generated electricity for daily life and domestic purpose. renewable energy solutions are becoming increasingly popular. photo voltaic systems are good abdullah (et-al), a smart on-grid solar charge controller (pp. 52-59) sukkur iba journal of emerging technologies sjet | volume 1 no. 2 july – december 2018 © sukkur iba university 59 examples of this. in order to implement a solar system, need of good charge controller is necessary for good efficiency and performance of our system. so hybrid charge controller is one of the best options to employ it in solar systems. due to availability of hybrid charge controller we can charge our battery either by solar energy in day time or charge our batteries by an a.c supply in cloudy days and in night time. so it is very beneficial for such application. references [1] md faysal nayan , s.m.safayet ullah “modelling of solar cell characteristics considering the effect of electrical and environmental parameters”,vol.1,no.2,pp.1001-1025, dec 2002 [2] cherng.j.k.–klang,j.k. “method for optimizing the charging of lead-acid batteries and an interactive charger” ,vol.1,no.08,pp.22-35, nov. 21, 1995 [3] anderson,e.–dohan,c.–sikora,“a solar panel peak power tracking system”, vol.2,no.02,pp.105-135, 2003 [4] v v prathibha bharathi, v pandurangadu2 and v v naga deepthi “car runs by solar energy”,vol. 4, no. 1 pp 2278 – 0149 , january 2015 [5] p.sathya, g.aarthi “modelling and simulation of solar photovoltaic array for battery charging application using matlab-simulink”, vol.1, issn: 2277-9655, november, 2013 [6] d.shmilovitz, “on the control of photovoltaic maximum power point tracking via output parameters”, ieee proc. elect. power appl.2005, pp 239-248. [7] md. rokonuzzaman, mahmuda khatun mishu, md hossam-e-haider and md. shamimul islam “design of a mppt solar charge controller in matlabsimulink gui environment” vol.1,pp. 22-23 february, 2017 [8]http://www.instructables.com/id/ard uino-solar-chargecontroller-version-20/ [9]https://www.victronenergy.com/upload/ documents/white-paper-which-solarcharge-controller-pwm-or-mppt.pdf [10] m. m. hoque, m.a. hannan, a. mohamed, "voltage equalization control algorithm for monitoring and balancing of series connected lithium-ion battery", journal of renewable and sustainable energy, vol. 8, pp. 025703, 2016. [11] s. m. çınar and e. akarslan ,”on the design of an intelligent battery charge controller for pv panels, electrical engineering. department”, conference university of afyon kocatepe, afyonkarahisar, vol 1, no 2,pp 13-39 ,october 2012 vol. 5, no. 2 | july december 2022 sjet | p-issn: 2616-7069 | e-issn: 2617-3115 | vol. 5 no. 2 july – december 2022 42 an optimized proportional integral derivative (pid) based power system stabilizer (pss) for damping of active power oscillations veer bhan1*, ashfaque ahmed hashmani1, abdul hakeem memon1 abstract: rising load demand and possibilities of short interruptions either due to temporary faults or equipment switching may lead to transient instability in terms of growing oscillations and eventually result in cascaded outages if not being damped properly and timely. to dampen such oscillations, the power system stabilizers (pss) are invariably installed to regulate the excitation of synchronous generators. in this research, a comparative analysis among the two design variants of pss i.e., lead lag and pid, is performed by comparing the overshoot and settling time of generator active power after disturbance, to observe the effect of each on the system characteristics and nominal conditions. the settling time with pid based pss is reduced by 46% in case of three phase short circuit fault and 80% in case of the single line to ground fault as compared to lead lag pss. thus, the results obtained show a better performance of pid based pss having better overshoot response and reduced settling time for symmetrical and unsymmetrical faults. keywords: active power oscillations, lead-lag pss, pid-based pss 1. introduction notwithstanding the improved security and tolerance of modern power systems towards temporary and permanent contingencies, the issues of stability and protection have been prevailing yet [1][2]. the stability of a power system refers to the condition where it maintains the state of equilibrium for normal operation and retains its acceptable characteristics after being subjected to local or global disturbances. the common disturbances include faults and load switching that introduce low-frequency oscillations into the power system and may lead to oscillatory instability if not being damped out adequately. one of the promising ways to compensate for such oscillations is to install power system stabilizer (pss) at the excitation of the synchronous generator, as shown in fig. 1. 1department of electrical engineering mehran university of engineering and technology jamshoro, sindh, pakistan corresponding author: veerhablani@gmail.com the pss aims at expanding the system stability limit with the help of modulation of generator excitation so that it can dampen the power swing modes with additional positive damping torque [3]. the modeling and design of different types of pss have been well-studied in the literature. using the static output feedback (sof) control approach, the researchers in [4] have proposed the direct implementation of pss having pid properties and compared it with various existing passive architectures. the idea is, however, simple and feasible to implement, but it does not ensure global stability. a novel pss structure to ensure the global transient stability of a microgrid system is discussed in [5]. the method has been evaluated against the mailto:veerhablani@gmail.com an optimized proportional integral derivative (pid) based power system stabilizer (pss) for damping of active power oscillations (pp. 42 48) sukkur iba journal of emerging technologies sjet | vol. 5 no. 2 july – december 2022 43 loading and faulty conditions considering the small-signal and transient stability criterion. fig. 1. conceptual representation of installation of pss into the power system in [6], the researcher has exploited the concept of model predictive control (mpc) to design a robust architecture of pss for improving the dynamic stability of a singlemachine infinite bus (smib) system. this system, owing to its predictive nature, can adapt to unknown conditions but is computationally ill condition and has a marginally slow response time. considering above discussed approaches, the overall objectives of this paper are: 1. to formulate and model the two designs of pss, i.e., leadlag and pid. 2. to investigate the effects of installing these types of pss onto the characteristics of the power system in the simulated environment of matlab simulink. to evaluate and compare the performance of these pss designs in terms of overshoot and settling time. 2. literature review various researchers have analyzed the performance of pss with different computational methodologies [7]. authors in [8] worked on the analysis of steady-state stability and improved it using eigenvalues and conventional pss for a thermal power plant in jamshoro, pakistan, taken as a case study. most of the power plants are equipped with a conventional power system stabilizer (cpss), which is of the lead-lag type and has fixed parameters [9]–[12]. however, lead-lag based conventional pss lacks reliability against different loading conditions. [4]. industrial utilities have used proportionalintegral-derivative (pid) controllers for their essential functionality and simplicity in structure. to function properly for a wide range of operating conditions, pid-based pss is proposed in [13]. also, pid controller-based pss structure has been presented for system stability enhancement by applying the controller on a generator connected with the infinite bus, and its performance has been compared without pss, with proportionalintegral (pi-pss), and with proportionalintegral-derivative (pid-pss). in [14], the researchers investigated the performance of a large hydro station using pid-based pss against the damping of active power oscillations. the gains of the installed pss model were chosen considering the frequency characteristics of the system under different loading and faulty conditions. likewise, the case study in [15] examined the pid-based pss model for a multi-machine system, but the gains were determined using particle swarm optimization considering the dynamic stability characteristics of the power system. the results of three different loading conditions from eigenvalue analysis show that the pid-based pss has improved steady state and dynamic performance compared with the lead-lag pss [16]. while tuning for stabilizer parameters has been presented in [17]–[20]. 3. research methodology to design a robust pss model that is not only resilient to external disturbances, thereby providing positive damping to local mode oscillations but also ensures optimal behavior by injecting torque variations in phase with speed deviations by considering the loading characteristics of the system. to evaluate the performance and effectiveness of the designed pss model, its dynamic damping test is carried out to validate that the resultant model can dampen active power oscillations effectively. for this purpose, two different models of pss, i.e., lead-lag and pid, are designed and analyzed in this paper. an optimized proportional integral derivative (pid) based power system stabilizer (pss) for damping of active power oscillations (pp. 42 48) sukkur iba journal of emerging technologies sjet | vol. 5 no. 2 july – december 2022 44 3.1. lead-lag pss model the block diagram representation of the lead-lag pss model is shown in fig. 2. where the stabilizing gain kstab determines the amount of damping provided and plays an essential role in the damping of active power oscillations. by increasing the gain value, damping increases up to a certain point, beyond which further increase in gain results in a decrease in damping. the wash-out filter is of a high-pass type used to remove the lowfrequency components or to prevent steady changes in speed from modifying the field voltage and enables the stabilizer to act upon the speed deviations only. the phase compensation is used to eliminate the phase lag between the exciter input (i.e., pss output) and the resulting electrical torque of the synchronous generator [3]. the input to this model can be either the speed deviation (∆ω) or the acceleration power (pa) i.e., the difference of mechanical power (𝑃𝑚) and electrical power (𝑃𝑒 ), as expressed by the equation shown in (1). 𝑃𝑎 = 𝑃𝑚 − 𝑃𝑒 (1) whereas the output is the stabilizing voltage (𝑉𝑠𝑡𝑎𝑏 ) with upper and lower bounds to restrict the terminal voltage of the synchronous generator within predefined limits. the overall transfer function of this pss model is expressed by the equation shown in (2). 𝑉𝑠𝑡𝑎𝑏 ∆𝜔 = 𝐾𝑠𝑡𝑎𝑏 𝑠𝑇𝑤+𝑠 2𝑇𝑤𝑇1 1+𝑠(𝑇2+𝑇𝑤)+𝑠 2𝑇𝑤𝑇2 (2) fig. 2. block diagram of lead-lag pss model the choice of tw, t1, and t2 depends upon the characteristics of the power system and the rating and configuration of the synchronous machine. the sufficient condition to determine their values states that the poles of the equation shown in (2) should be real and lie on the negative complex plane. the parameters given in equation (2) are enumerated in appendix a. 3.2. pid-based pss model the lead-lag architecture, however, is simple and easy to realize but does not guarantee global stability and robustness against varying operating conditions under all disturbances. the standard pid controller with unity feedback is exploited to achieve state stabilization of rotor swings, as shown in fig. 3. fig. 3. schematic representation of pid-based pss model this design works on an error signal originating either in speed (ω) or acceleration power (pa), as mathematically described by the equation shown in (3). 𝑉𝑠𝑡𝑎𝑏 = 𝐾𝑃 (⍵𝑑 − ⍵𝑐 ) + 𝐾𝐼 ∫(⍵𝑑 − ⍵𝑐 )𝑑𝑡 + 𝐾𝐷 (⍵�̇� − ⍵𝑐 )̇ (3) where kp, ki, and kd are the controller gains, ωd and ωc represent desired and current rotor speed, respectively, and their associated acceleration are denoted by ω˙d and ω˙c. the output of the controller is a voltage signal (𝑉𝑠𝑡𝑎𝑏 ), like the lead-lag pss, given to the excitation system, which as a result, produces the additional torque responsible for the damping of active power oscillations. for this pss model, asymptotic stability is achieved by the proper selection of gain matrices. the optimal choice of these gain matrices is made in such a way that equation shown in (4) is satisfied [21]. �̈� + 𝐾𝐷 �̇� + 𝐾𝐼 ∫ 𝑒𝑑𝑡 + 𝐾𝑃 𝑒 = 0 (4) + + + an optimized proportional integral derivative (pid) based power system stabilizer (pss) for damping of active power oscillations (pp. 42 48) sukkur iba journal of emerging technologies sjet | vol. 5 no. 2 july – december 2022 45 4. results and discussion the presented models of pss have been evaluated onto the simulink model of a thermal power plant connected with an infinite bus, i.e., single machine infinite bus (smib) under symmetrical and unsymmetrical fault. the two-evaluation metrics, i.e., overshoot, i.e., % of the rise in the value of respective quantity over to its nominal value and settling time, i.e., the duration within which the system has retained its normal state. the generator active power for the presented pss models against a three-phase short circuit (symmetrical) fault at constant loading conditions is shown in fig. 4 to fig. 7. fig. 4. generator active power against three-phase short circuit fault without pss fig. 5. generator active power against three-phase short circuit fault with lead-lag pss fig. 6. generator active power against three-phase short circuit fault with pid-based pss fig. 7. generator active power against three-phase short circuit fault with different pss table i. summary of overshoot and settling time against three-phase short circuit fault model three phase short circuit fault generator active power overshoot (pu) settling time (s) without pss 0.41 >10 lead-lag pss 0.45 1.3 optimized pid pss 0.35 0.7 the fault occurs at 1 sec, as can be seen from tables i and ii, that owing to the severity of three-phase short circuit fault, large and an optimized proportional integral derivative (pid) based power system stabilizer (pss) for damping of active power oscillations (pp. 42 48) sukkur iba journal of emerging technologies sjet | vol. 5 no. 2 july – december 2022 46 high frequency deviations and transients are observed into the output power of the generator as compared to a single line to ground fault. further, pid-based pss is robust and effective in mitigating the local area oscillations with reduced overshoot and settling time. fig. 8. generator active power against the single line to ground fault without pss fig. 9. generator active power against the single line to ground fault with lead-lag pss fig. 10. generator active power against the single line to ground fault with pid-based pss in comparison, the lead-lag pss performs better than without pss in both scenarios, with reduced overshoot and settling time. the generator active power for the presented pss models against the single line to ground (unsymmetrical) fault at constant loading conditions is shown in fig. 8 to 11. fig. 11. generator active power against the single line to ground fault with different pss table ii. summary of overshoot and settling time against single line to ground fault model single line to ground fault generator active power overshoot (pu) settling time (s) without pss 0.17 >10 lead-lag pss 0.12 1.3 optimizedpid pss 0.08 0.26 it is evident from table i and ii that the pid-based pss shows lesser overshoot as well as settling time compared to lead-lag and without pss. on the other hand, lead-lag pss performs better than without pss, but unfortunately, it under-performs in achieving less overshoot and settling time than pidbased pss. an optimized proportional integral derivative (pid) based power system stabilizer (pss) for damping of active power oscillations (pp. 42 48) sukkur iba journal of emerging technologies sjet | vol. 5 no. 2 july – december 2022 47 5. conclusion this research analyzed and discussed the characteristics and effects of integrating the different designs of pss into the performance of the overall power system. the power system under investigation was the thermal power plant in the matlab simulink environment, and the models of respective pss were designed by considering the rating, loading, structural properties of the power system, and as well as severity of the simulated contingencies. it has been observed that the pid-based pss adapts well to varying conditions irrespective of the nature and severity of the conditions and has reduced overshoot and reduced settling time, thus providing better damping efficiency but requiring explicit tuning of its hyperparameters. whereas the lead-lag design, however simple and uses intrinsic properties of the system, has lower damping efficiency than pid-based pss and reasonable settling time. the settling time with pid-based pss is reduced by 0.6 seconds in case of a three-phase short circuit fault and 1.04 seconds in case of a single line to ground fault as compared to lead-lag pss. therefore, it can be concluded that with respect to the oscillations in generator active power, pid-based pss performs better. considering this, in future work, the model of the fuzzy system will be exploited to achieve such results. other than this, an iterative learning approach will be used that will update its internal state based on the varying dynamic conditions of investigated power system. w this is to declare that there is no conflict of interest. the authors are pleased to express their gratitude for the technical support provided by the department of electrical engineering, mehran university of engineering and technology authorities for their support. n x table iii. parameters for the lead-lag pss parameter value kstab 20 tw 2 vstab max 0.15 vstab min -0.15 references [1] katyara, s., hashmani, a., chowdhary, b.s., musavi, h.a., aleem, a., chachar, f.a. and shah, m.a., 2021. wireless networks for voltage stability analysis and anti-islanding protection of smart grid system. wireless personal communications, 116(2), pp.13611378. [2] shaikh, m.f., katyara, s., khand, z.h., ali shah, m., staszewski, l., bhan, v., majeed, a., shaikh, s. and zbigniew, l., 2021. novel protection coordination scheme for active distribution networks. electronics, 10(18), p.2312. [3] kundur, p.s. and malik, o.p., 2022. power system stability and control. mcgraw-hill education. [4] chaubey, p., lather, j.s., yelisetti, s., manda, s. and yadav, n.k., 2019. robust power system stabilizer based on static output feedback approach to enhance power system stability. energy procedia, 158, pp.29602965. [5] kim, j.j. and park, j.h., 2021. a novel structure of a power system stabilizer for microgrids. energies, 14(4), p.905. [6] ismail, m. and bendary, a., 2021. improvement of dynamic stability of a single machine infinite-bus power system using mpc based power system stabilizer. erj. engineering research journal, 44(4), pp.385390. [7] devarapalli, r., sinha, n.k. and garcía márquez, f.p., 2022. a review on the computational methods of power system stabilizer for damping power network oscillations. archives of computational methods in engineering, pp.1-27. [8] shahani, z.a., hashmani, a.a. and shaikh, m.m., 2020. steady state stability analysis and improvement using eigenvalues and pss. engineering, technology & applied science research, 10(1), pp.5301-5306. [9] kyriakides, e. and farmer, r.g., 2004. modeling of damping for power system stability analysis. electric power components and systems, 32(8), pp.827-837. [10] larsen, e.v. and swann, d.a., 1981. applying power system stabilizers part i: general concepts. ieee transactions on an optimized proportional integral derivative (pid) based power system stabilizer (pss) for damping of active power oscillations (pp. 42 48) sukkur iba journal of emerging technologies sjet | vol. 5 no. 2 july – december 2022 48 power apparatus and systems, (6), pp.30173024. [11] furuya, s. and irisawa, j., 2006. a robust h∞ power system stabilizer design using reducedorder models. international journal of electrical power & energy systems, 28(1), pp.21-28. [12] tse, c.t. and tso, s.k., 1993. refinement of conventional pss design in multimachine system by modal analysis. ieee transactions on power systems, 8(2), pp.598-605. [13] soliman, m., elshafei, a.l., bendary, f. and mansour, w., 2010. robust decentralized pid-based power system stabilizer design using an ilmi approach. electric power systems research, 80(12), pp.1488-1497. [14] prabhakaran, k.k., tiwari, r., nayak, s.r. and chelliah, t.r., 2020, december. performance investigation on damping of active power oscillation in the large hydropower plant with power system stabilizer. in 2020 ieee international conference on power electronics, drives and energy systems (pedes) (pp. 1-6). ieee. [15] dasu, b., kumar, m.s. and rao, r.s., 2019. design of robust modified power system stabilizer for dynamic stability improvement using particle swarm optimization technique. ain shams engineering journal, 10(4), pp.769-783. [16] mahdavian, m., amini, a.a. and hashemi, m., 2022. design of a pid-pss power system stabilizer for single-machine infinite-bus power system. signal processing and renewable energy, 6(2), pp.67-83. [17] farhad, z., ibrahim, e.k.e., tezcan, s.s. and safi, s.j., 2018. a robust pid power system stabilizer design of single machine infinite bus system using firefly algorithm. gazi university journal of science, 31(1), pp.155172. [18] asv, v.l., manyala, r.r. and mangipudi, s.k., 2020. design of a robust pid-pss for an uncertain power system with simplified stability conditions. protection and control of modern power systems, 5(1), pp.1-16. [19] ghany, m.a. and shamseldin, m.a., 2020. model reference self-tuning fractional order pid control based on for a power system stabilizer. international journal of power electronics and drive systems, 11(3), p.1333. [20] el‐dabah, m.a., kamel, s., abido, m.a.y. and khan, b., 2022. optimal tuning of fractional‐order proportional, integral, derivative and tilt‐integral‐derivative based power system stabilizers using runge kutta optimizer. engineering reports, 4(6), p.e12492. [21] genesio, r., tartaglia, m. and vicino, a., 1985. on the estimation of asymptotic stability regions: state of the art and new proposals. ieee transactions on automatic control, 30(8), pp.747-755. format template vol. 1, no. 2 | july december 2018 sjet | issn: 2616-7069 | vol. 1 | no. 2 | © 2018 sukkur iba 60 preparation and investigation of coal slurry fuel blended with industrial wastewater for use in thermal power generation mueed akhtar1, ehsan ali1 abstract: the scientific novelty of the research is that coal slurry fuels have been prepared by blending pulverized coal with industrial effluents and characteristics were compared with the slurry comprising fresh water. this innovative technique results in saving fresh water. also, this methodology puts local coal reserves of pakistan to use in an innovative way which is both efficient and friendlier. this novel idea puts local coal in use for power production. the coal in pakistan in not in use because of the difficulties in mining and also due to the lack of concern of the government regarding using countries own resources for power production. instead the policies regarding importing expensive fuels from gulf states are a common practice. the novelty of this idea serves the idea of both greener and sustainability of energy. keywords: coal, coal slurry fuel, waste water 1. introduction pakistan is majorly an agriculture-based economy but in the past decade there has been a major development in the industrial sector. this industrial development results in more energy requirements and more consumption. in pakistan total installed capacity of power generation is 22,000 mw. average production of power is almost 17,000 mw and the shortfall of energy lies between 5,000 mw to 6,000 mw. total 80.7% of the supply in the energy mix of pakistan is dominated by oil and gas combined. in fiscal year 2013-2014 energy production from oil was 32% of the total energy mix. from gas 34% of the total energy mix is produced. from coal 3,590,386 toe were generated and it was 0.1% of the total energy mix. besides fossil fuels, the other major source of energy is hydel from which total of 30% of the total energy mix. 1 school of chemical engineering, the university of faisalabad, tuf, faisalabad, pakistan corresponding email: mueed.akhtar@tuf.edu.pk rest is obtained by nuclear and other resources like renewables and lpg etc.[1]. in pakistan, vast quantities of coal are present. each province has got substantial amount of coal reserves. reserves and their calorific values are shown in the table below. mueed akhtar (et-al), preparation and investigation of coal slurry fuel blended with industrial wastewater for use in thermal power generation (pp 60-65) sukkur iba journal of emerging technologies sjet | volume 1 no. 2 july – december 2018 © sukkur iba university 61 table i. coal reserves from the above data it is quite clear that pakistan has more than enough coal resources. with these resources pakistan can generate 100,000 mw of energy for more or less 30 years. in pakistan most of the coal found has either high sulphur values or high moisture content. if the coal has perfect quantities of all the components, the coal is in very little quantities. it is clear that the largest coal reserve in sindh is thar coal which 175.5 billion out of 184 billion of total reserves of sindh. but it contains 29.60-55.50% moisture. total coal reserves in baluchistan are 217 million tons out of which 32 million tones are considered to be mineable. the classification of coal is sub-bituminous to bituminous. heating values are in the range of 9,63715,499 btu/lb with low ash contents but high sulfur contents. now talking about punjab, the total coal reserve is reported to be 22 million tons. it has relatively low moisture, ash content and sulfur content than salt range coal mine, but still not up to mark the optimum quality coal. quality of coal is also qualified as sub-bituminous coal. in kpk, there are combined reserves estimated to be 91 million tons. coal of both mines is reported to be subbituminous with heating values in the range of 9,386-14,217 btu/lb. coal from both mines have low sulphur and ash contents also with low moisture contents[2]. 1.1 environmental issues pakistan is a developing country. in pakistan, there are multiple industries, growing day by day. also the population of pakistan is increasing day by day. pakistan is now the home of more than 200 million people. increased population means more energy requirement, more consumer products, more industrial growth, also more municipal waste and industrial waste. pakistan is basically an agriculture-based economy but now this economy is shifting towards industry. there are textile mills, sugar mills, cement plants, fertilizer plants, consumer products industry, and food & beverage industry. all these industries use water for processing. if water is used for processing, obviously there is some water wastage. pakistan is a country where most of its energy is produced from fossil fuels like oil and gas. a very less amount of energy is produced from renewables. in the recent years there is a remarkable shift in the government’s policy, to make the process of making energy efficient, green, cleaner and sustainable. to have a long term sustainable better economy, pakistan must address the environmental challenges which comes along with a better and stable economy. these problems include industrial waste water, municipal waste water, chemical spills in clean water, soil erosion, deforestation, salinity, water logging, fresh water pollution, just to name a few. 1.1.1 water pollution in pakistan, water gets polluted by a number of means. mainly these are classified into following classes.  water pollution due to raw sewage.  water pollution due to industrial waste water.  water pollution due to agriculture runoffs. all these pollutions have driven fresh water supply to a limited amount. majority of the population does not have proper supply of fresh drinking water. urbanization and implementation of modern technologies is also causing the pollution of water. according to the research conducted by pakistan medical research council, majority of the diseases in common population is caused by drinking of substandard or polluted water. this water province reserves (million tons of coal) calorific value (btu/lb) sindh 1,84,623 5,21913,555 baluchistan 217 9,63715,499 punjab 235 9,47215,801 kpk 91 9,38614,217 ajk 9 7,33612,338 total 185,175 mueed akhtar (et-al), preparation and investigation of coal slurry fuel blended with industrial wastewater for use in thermal power generation (pp 60-65) sukkur iba journal of emerging technologies sjet | volume 1 no. 2 july – december 2018 © sukkur iba university 62 pollution is causing many diseases like typhoid, cholera and other gastric diseases. this polluted water when seeps through the soil, mixed with pockets of fresh underground water also makes it polluted[3]. 1.2 coal water slurry fuel cws is a fuel which consists of finely pulverized (less than 20 micrometers in diameter) coal particles suspended in water in the presence of emulsifying agents/oil/stabilizers. cws usually consists of 55-70% of pulverized dispersed coal particles and 30-45% of water. coal-water slurry fuel classified based on following properties: ignition temperature 800—850 °с, combustion temperature 950—1150°с, and calorific value 5800-6500 kcal/kg. this fuel can be used to fire boilers for steam production. another application for this type of slurry is gasification. at present there are multiple gasification processes developed to utilize this technology like ge energy (texaco), opposed multi-burner process, etc.[4]. the most desirable features of cwsf are high solid loading, good stability, good rheological behavior, low viscosity, low ash content and relatively high heating values. usually cwsf is prepared by maintaining a solid to water loading of 70% and 30% respectively. these ratios may vary from 70:30 – 60:40. if water is added above 40%, then heating value of the fuel will be decreased. a small percentage (up to 1%) of additives is also added for better dispersion, uniformity and stability of solid loading[5]. 2. materials and methods coal was obtained from pioneer cement pvt. ltd plant located near khushab district, pakistan. they imported the coal from waterberg coal field located in south africa. the coal obtained was already pulverized and the average particle size was 90µm. this coal was mixed with three different industrial waste waters. spent wash was obtained from noon sugar mills distillery pvt. ltd located in bhalwal near sargodha district, pakistan. similarly, waste water was obtained from fauji foods located in bhalwal near sargodha district, pakistan and sapphire textile mills limited located in lahore, pakistan. an ionic surfactant named as sodium naphthalene sulfonate formaldehyde condensate was selected as dispersant which was imported from shandong wanshan chemical co. ltd., china and sodium lingo-sulfite was selected as the stabilizer which was imported from jinan yuan sheng chemical technology co., ltd, china. all the raw materials were collected and brought to the bio fuels lab at uspcas-e nust, islamabad pakistan. for both types of slurries solid loading was kept 65% and liquid ratio was kept 35% by weight. 1% additives were added, both in equal quantities. 400g samples of both slurries were prepared in a mixer driven by 800w variable speed motor. 260g of coal, 139g of water, 0.5g of nansf and 0.5g of sodium lignosulfite were added into the container and then mixed at 1357 rpm for 30 minutes. after 30 minutes the coal water slurry fuel (cwsf) was collected into sample bottles. the same procedure was repeated with waste waters to make coal waste water slurry fuels (cwwsf) under ambient conditions. 3. results and discussions after preparing samples of all the slurries, these samples were sent to pioneer cement for testing. three types of tests were performed on both the samples. the tests carried out were focused on finding out the qualities of the fuel in order to determine whether or not it could be used effectively. a number of tests were performed to determine the quality of coal. these tests include % total moisture (iso 11722), % ash content (iso 1171), % sulphur (iso 351), % inherent moisture (iso 331), % volatile matter (iso 351) and calorific value (iso 1928). all the samples were prepared at pioneer cement. as all of them were prepared from finely pulverized coal, now size reduction for the preparation of samples were needed. all the samples were dried by placing them in an air circulated furnace a 40 degree celsius. after performing the analysis, the following analysis were obtained. mueed akhtar (et-al), preparation and investigation of coal slurry fuel blended with industrial wastewater for use in thermal power generation (pp 60-65) sukkur iba journal of emerging technologies sjet | volume 1 no. 2 july – december 2018 © sukkur iba university 60 table ii. analysis of coal, cwsf and cwwsf samples sr. no. analysis coal coal water slurry fuel coal waste water slurry fuel (textile) coal waste water slurry fuel(alcohol distillery) coal waste water slurry fuel (dairy) 1 % inherent moisture 2.46 1.77 1.42 1.48 2 % total moisture 3.12 38.94 39.45 35.54 38.22 3 % ash content 16.22 16.72 16.56 17.86 16.80 4 % volatile matter 30.69 30.64 27.01 28.41 26.99 5 % sulphur 0.69 0.81 0.83 0.96 0.85 6 gross calorific value (cal\gm)adb 6260 6245 6228 6014 6209 in the above table, there are given the properties of five samples. one being the coal and other four are coal slurry fuels. coal is marked as a basic standard and all other values are for comparison. all the samples of coal slurry fuel have inherent moisture. this is due to the presence of water in the form of fresh water or in the form of waste water. also due to this same reason the total moisture in the coal slurry samples is higher. ash contents of all the samples are almost the same as that of coal sample except the cwwsf (alcohol distillery). this is because of the properties of alcohol distillery spent wash. spent wash already contains solid material. volatile material in cwsf is in accordance with the coal sample. but for cwwsf sample the levels are different. this is again due to the different properties of different waste waters. sulphur content in coal sample is 0.69%. this value is perfect for use in thermal power generation. it should be less than 1%. in cwwsf sample this value is different but all the values are within the range. coal sample has the maximum gcv, all cwwsf samples have lowered gcvs but this difference is negligible. 4. recommendations on the basis of all the above discussions it is obvious that all the samples cwwsf are feasible for use in thermal power production. this solves many problems. the coal slurry fuels are easy to handle. they have better combustion efficiencies. ash formation after combustion is less. sox emissions after combustion is also low. this is because of its composition. it contains water which forms acids with sulphur. due to these acids formation there are low sox emissions. also nox emissions are reduced due to the presence of water in the slurry. the slurry is combusted at lower temperatures. nox are produced due to the combustion at high temperatures. this is the only reason of low nox productions.[6] but there is also a down side. we need to make modifications in the internal design of the existing and new boiler\steam generation systems. corrosion is accelerated due to the production of acids during combustion. this is a serious problem. it shortens the life of equipment increases, wear and tear. if not inspected and evaluated, it may cause serious damage to internal parts of the boiler/steam generator. it also makes maintenance of equipment more difficult. to prevent this, we need to preinstall an anticorrosive coating on the internal parts of the boiler/steam generator. plus, if we replace this fuel in existing systems, we need to make major modifications in the design. for example, if the existing system is on furnace oil, we need to install a new csf based burner. also some modification is need to extract ash from the system. the same modifications are mueed akhtar (et-al), preparation and investigation of coal slurry fuel blended with industrial wastewater for use in thermal power generation (pp 60-65) sukkur iba journal of emerging technologies sjet | volume 1 no. 2 july – december 2018 © sukkur iba university 61 needed if natural gas based thermal systems are installed. mostly if natural gas based systems are installed, they use gas turbines instead of boilers/ steam generators. some modifications are also required in the process. the wet milling equipment is required to prepare the slurry. also some slurry pumps are required for pumping and transport. a suggested flow sheet diagram is shown below. fig 1: flow sheet diagram according to some literature energy production from cwsf is cheaper than furnace oil and gas. table iii: cost comparison sr. no fuel price\mj (pkr) 1 furnace oil 2.6 2 natural gas 0.63 3 cwsf 0.42 although there is a very small difference between natural gas and cwsf, gas reserves in pakistan are depleting. government is trying to import lng as a solution but it is expensive. so this difference will not be very little if compared with lng[7]. 5. conclusion energy production and waste water treatment are two major issues in the world and especially for pakistan. energy production from coal is usually avoided due to its environmental hazards. but according to the depleting conditions of other two resources (oil and gas). we need to divert the production of energy from oil and gas to coal to balance it out and to make it somewhat sustainable. coal gasification, coal to liquid technologies are some of the greener technologies but they are very expensive. instead coal slurry fuel technology is much cheaper and feasible and if we use waste water instead of fresh water then the problem can be addressed for waste water treatment or waste water disposal. from the experiments conducted following points can be concluded.  all the properties of cwwsf are in accordance with coal sample, which means the cwwsf are viable for use in thermal power production.  some capital investment is required for retrofitting the existing systems and acquiring new systems.  ash formed is best fit to be used as filler in the production of concrete.  per mj of energy cost of production from cwsf is less than when produced from furnace oil and natural gas.  less sox and nox emissions are recorded by using this fuel. references [1] ©. h. d. i. of pakistan, “pakistan energy yearbook,” 2014. [2] private power and infrastructure board, “power, coal potential, generation,” 2004. mueed akhtar (et-al), preparation and investigation of coal slurry fuel blended with industrial wastewater for use in thermal power generation (pp 60-65) sukkur iba journal of emerging technologies sjet | volume 1 no. 2 july – december 2018 © sukkur iba university 62 [3] s. r. (university of karachi), “environmental challenges in pakistan,” sharnoffs global views, 2014. [4] j. zhu, g. zhang, g. liu, q. qu, and y. li, “investigation on the rheological and stability characteristics of coal-water slurry with long side-chain polycarboxylate dispersant,” fuel process. technol., vol. 118, pp. 187–191, 2014. [5] q. he, d. xie, r. xu, t. wang, and b. hu, “the utilization of sewage sludge by blending with coal water slurry,” fuel, vol. 159, pp. 40–44, 2015. [6] x. zhao, w. zhu, j. huang, m. li, and m. gong, “emission characteristics of pcdd/fs, pahs and pcbs during the combustion of sludge-coal water slurry,” j. energy inst., vol. 88, no. 2, pp. 105– 111, 2015. [7] m. irfan, m. a. irfan, a. khan, i. ullah, n. wazir, s. arabia, s. arabia, and i. estate, “the case of coal water slurry fuel for industrial use in pakistan,” vol. 9, no. 6, pp. 460–465, 2015. ieee conference paper template vol. 2, no. 1 | january june 2019 sjet | p-issn: 2616-7069 | e-issn: 2617-3115 | vol. 2 | no. 1 | © 2019 sukkur iba 1 investigation of lsb based image steganographic techniques in spatial domain for secure communication shahid rahman1, fahad masood1, wajid ullah khan1, abdus salam1, syed irfan ullah1 abstract: confidentiality, integrity and authenticity for secure data are required for all the conveying bodies. distinctive methodologies are utilized to adopt the security issues like digital certificate, digital signature and cryptography. these techniques alone cannot be traded off. steganography is one of the answers to the security as it hides the secret information. steganography has the importance in view of its exponential advancement and riddle data of possible pc customers over the web. it can likewise be depicted as the examination of indistinct information that usually manages the methodologies for concealing the closeness of the passed-on message. mostly part of data covering is refined in correspondence to image, content, voice or sight and sound substance for copyright, military correspondence, confirmation and various diverse purposes. in this paper least significant bit (lsb) technique for image steganography has been observed under various cases. results for different scenarios have been looked at and the condition of the science assessment and examination of various accessible strategies for steganography have been given. the principles pursued are equivalent to give into the writing. normal models and procedures drawn from the literature are utilized to obtain the results. this survey concludes with recommendations and supporters for the caries-oriented mechanism. keywords: steganography, data concealing, cover writing 1 department of computing abasyn university peshawar kpk, pakistan corresponding author: rahmanshahid@gmail.com 1. introduction steganography is derived from two greek words, "steganos" means’ ‘covered/protected" and "graphic" representing "writing". so steganography infers covered writing. it is one of a kind branches of "information stowing away or hiding". it is characterized as "the way towards composing secret message with the end goal that the nearness of the message is just known to the sender and receiver"[1]. it is the workmanship and study of undetectable communication and a push to cover the presence of the embedding data. cover steganography is the art of conveying information that can’t be distinguished or detected [2]. steganography not only changes the course of action of the mysterious message, but also covers it inside a coverdissent or question. resulting to conceal strategy cover test and stego-image (passing on secured data contradict) is indistinguishable. in this manner, steganography (concealing data) and cryptography (anchoring data) are absolutely astonishing from one another. by virtue of subtlety or shrouded factors it is hard to recuperate the data without knowing the framework in steganography. systems for steganography insinuated as steganalysis are the same as cryptanalysis [3]. a. digital medium for steganography there are five types of steganography techniques used for embedding secret messages depending upon a cover protest or object. shahid rahman (et al.), investigation of lsb based image steganographic techniques in spatial domain for secure communication (pp. 1 12) sukkur iba journal of emerging technologies sjet | volume 2 no. 1 january – june 2019 © sukkur iba university 2 i) image steganography: a steganography type, in which image is used as a cover object. in this framework, pixel energy of the cover image is utilized to cover information. images are thought to be the best cover objects for disguising information since it contains a generous measure of respective bits [4]. ii) network steganography: in network steganography, network protocols are used as cover object such as tcp, ip, udp and icmp and so on. data is covered up in a few fields of the header of tcp/ip packet that are open or never utilized [5]. iii) audio steganography: in this type audio is utilized as a cover object for data embedding. it has turned out to be an extremely critical medium because of voice over ip (voip) factor. it uses some digital plans like as waveform audio file format (wave), audio video interleave (avi), moving picture experts group (mped), musical instrument digital interface (midi) etc. [6]. iv) video steganography: in video steganography, collection of an image (video) is utilized as a cover object for concealing data. this strategy is able to shroud any type of records or data into computerized video design. discrete cosine transforms usually modify values 8.667 9. shrouded information for every image in video is utilized which is not recognizable by the hvs. the formats utilized by video steganography are mp4, mpeg, h.264, and avi and so on [7, 8]. vi) text steganography: in text steganography text is utilized as a cover object. in this strategy mystery message is covered up in the nth letter of each cover text. text steganography is thought to be the most difficult type of steganography because of the absence of excess in text when contrasted with different kinds of steganography. however, it requires less memory and is used for straightforward information [8]. fig.1 shows the digital mediums for steganography. fig.1. digital medium of steganography b. structure of steganography steganography has three main parts. i) the cover or carrier: it can be an image or painting, a digital image (tiff, jpg, bmp, png), an mp3 (audio files), a text file, a video file or tcp/ip packet as well. it is the object that will carry the hidden message. ii) the message: it can be a simple text or content, a secret image, an audio or video which will be transmitted securely. iii) the key: it can be a password, pattern, a black-light or a pseudo random number known to both sender and receiver. it is used at the time of embedding and extraction of secret information. it provides more protection against third parties/hackers. fig.2. image steganography [1] fig.2 shows a fundamental plan of image steganography. secret image is hidden within the image in such a manner that the intended shahid rahman (et al.), investigation of lsb based image steganographic techniques in spatial domain for secure communication (pp. 1 12) sukkur iba journal of emerging technologies sjet | volume 2 no. 1 january – june 2019 © sukkur iba university 3 user is prevented to detect the hidden message. stego-image is formed through an embedding algorithm. the stegoimages when formed have a mirror distortion of the image which is negligible for the naked eye. the hidden message can be an extracted algorithm from the stego-object. c. categorizations of image steganography image steganography is classified in different types on the basis of measuring algorithm which is shown in table-1[10]. i) perceptual transparency: once procedure is concealed into a carrier object, detectable quality will be debased into embedded image as equate with the original-object. ii) high payload or capacity: in cover object extreme mass of information can be inserted. iii) robustness: information should remain in place after covering, if embedded -image is changed, for example, editing, filtering, scaling and expansion of clamor (noise). iv) temper protection: it is a problematic issue to change the secret message after it has been secured into embedded object. v) calculation complexity: how much costly it is computationally to embed and extract a covered message? table i: measuring algorithm table 1 shows the measuring algorithms for steganography, which is the basic criteria of steganography which will be analyzed through different existing methods in spatial domain based on these measuring algorithms which is shown in table v. d. techniques of image steganography image or image steganography plans can be confined into following area: i) methods of spatial domain: in spatial steganography distinctive executions are available. lsb based steganography is one of the smallest complex techniques that covers an inside secret message in the lsb's of pixel without showing different distinguishable damages or twisting. changes in the estimation of the lsb are refined or impalpable for hvs. some standard approaches in spatial domains are given below: • ebe (edges based embedding method) • lsb (least significant bit) • rpe (random pixel embedding method) • gray level modification and multi level encryption (mle) • hidden data pixel mapping method • connectivity method or labelling • cyclic steganography randomization methods • pixel value differencing (pvd) • method of pixel intensity • method of content or texture • shifting methods of histogram there are some common focal points and weakness of a spatial area based on lsb methods: focal points: • lesser shot for debasement of the cover object. • in the image extreme size of data or information can be embedded. weaknesses: • less energy, with manipulation of image concealed information can be lost. • concealed data can be effectively crushed by open assaults if there is no robustness. ii) transform domain: in this technique we initially change the image from spatial space in recurrence area, conceal the mystery message and change it to the spatial domain. to conceal data utilizing these systems, measures advantages disadvantages perceptual transparency(hvs) high low high capacity (pay load) high low calculation complexity low high robustness (security) high low temper protection high low shahid rahman (et al.), investigation of lsb based image steganographic techniques in spatial domain for secure communication (pp. 1 12) sukkur iba journal of emerging technologies sjet | volume 2 no. 1 january – june 2019 © sukkur iba university 4 distinctive calculations and changes are connected with images which increment its many-sided quality. this strategy is thought to be considerably more grounded than spatial domain procedures. this method shroud data in those territories of the image that are less powerless by image pressure, trimming, and cropping. this system less inclined to measurable assaults and image corruption is additionally kept at least as we change coproficient in the change space, they have also brought down the payload and not are against editing, turn, interpretation and commotion [11]. some transform domain methods are: coefficient bits embedding • reversible method or lossless • discrete fourier transform (dft) • discrete wavelet transform (dwt) • discrete cosine transform (dct) iii) misrepresentations or distortion techniques: in this framework we require information of the chief cover picture with the confining strategy. here the decoder capacity check between the primary cover picture and the wasted cover picture with a specific extreme target to re-establish the mystery message. the encoder adds a social occasion of advancement to the cover challenge. thus, data is explained as being secured by flag twisting [12]. using this structure, a stego dissent or question is made by applying a course of action for adjustment of the cover picture. this movement of modification is used to rewrite the problem message required to transmit [13]. the message is encoded in pseudo-haphazardly picked pixels. the stegopicture is fascinating in association with the cover picture at the given message pixel, the message bit is a "1." normally it is “0”. the encoder can change the "1" respect pixels in such a course to the point that the honest properties of the picture are not influenced. regardless the need for sending the cover picture restrains the upside of this framework. in any steganographic structure, the cover picture to never be utilized more than once. on the off chance that an aggressor changes the stego-picture by altering, scaling or turning, the beneficiary cannot recollect it. from time to time, if the message is encoded with spoil reviewing the data, the change can even be traded and the fundamental message can be recovered [14]. iv) filtering and masking: this method conceals data by denoting an image similarly as paper watermark. this strategy embeds the data in the huger regions than simply concealing it into the noise level. the concealed message is more important to cover picture. they are more joined into the picture when watermarking methods can be associated without the fear of picture damage in light of pressure. some focal points and weaknesses of filtering and masking techniques: focal point: • significantly the said technique is much powerful as compared to least significant bit. data is covered up into unmistakable slices of the image or picture. weaknesses: • strategies can be associated just excessively dim or dark scale pictures and restrict it to 24 bits. 2. analysis steganography is an upcoming research area that uses images, videos, and network protocols, and audio for information concealment. from the last time in the spatial domain, several approaches for digital steganography have been proposed. these approaches are based on lsb substitution, edge based embedded, and pixel indicator based embedded. every approach has its relating advantages and disadvantages. some methods have high payload limits and great softness were blurriness depend on the chosen cover for covert or unknown information, concealing (spatial domain) but more vulnerable against assaults (noise tossing, rotation, revolution, resizing and so forth) while other schemes are strong against factual or statistical assaults, so far, they have brought down payload boundary. this implies that is reliably an exchange off between the three mechanisms (payload, imperceptibility& robustness). we will summarize different methods with their related advantages and disadvantages based on image steganography, which is discussed one by one below. shahid rahman (et al.), investigation of lsb based image steganographic techniques in spatial domain for secure communication (pp. 1 12) sukkur iba journal of emerging technologies sjet | volume 2 no. 1 january – june 2019 © sukkur iba university 5 hanling et al. proposed a new pixel esteem (value) differencing procedure; for data embedding near the goal pixel it used the three pixels. it utilizes essential k-bit lsb technique for mystery information implanting with high refinement regard where the number of k-bit is assessed by pretty much three pixels. it basically uses a perfect pixel adjustment method on target pixels to hold better visual quality and high breaking point. histogram of stego-picture and cover-picture is generally same in the great position of the procedure, however dataset for tests are closed to nothing [15]. channalli et al. proposed lsb based picture covering approach. conventional outline bits (stego-key) are utilized to cover information. the minimum noteworthy piece of the pixel is adjusted relying on the (stegokey) layout bits and the secret message bits. representation bits are composite of mxn measure lines and regions (of a piece) and with erratic key esteem. whenever fulfilled it change the second lsb bits of cover picture generally continues as already. every illustration bit is facilitated with the message bit in covering the system. this method centers to achieve security of masked message in the stego-picture using a run of the mill case key. the major disadvantage in the proposed procedure his a low covered farthest point since single secured bit requires a bit of (mxn) pixel [16]. jung, k. h et al. proposed a strategy for multi-pixel differencing (mpd) for data implanting, it process aggregate of refinement estimation of four pixels square and uses extra two pixels to scale smoothness of each pixel. it is utilized for little refinement esteem. for high complexity esteem it uses a multi pixel differencing system for data covering. so exploratory dataset is too much obliged, but quality is its straightforwardness of figuring [17]. yang, et al. proposed a data covering methodology to cover the data using lsb where it finds the darkness locale of the picture. using 8 pixels organize plans for concealing data bits; it changes over it to twofold picture and denotes each dissent. the strategy requires high tally to discover diminish region. its openness and has no endeavoured to high surface sort of picture. thoroughly, endless supply of image which covers its limits. [18] mahdi et al. proposed another picture steganography strategy, with assertion of emotional pixel of the required picture region and in light of lsb substitution. the mystery key is incorporated by lsb pixels this technique is centred to upgrade. a mystery message must be concealed if it creates irregular numbers and picks the region by combining. it is not yet considered a perceptual straightforwardness but the nature of the technique is its security of hiding messages in stego-image. [19]. babita et al. proposed a new image steganography method, to embed data. it uses 4 lsb of each rgb channel. it applies focuses sifting to upgrade the possibility of the stego picture and encodes the refinement of cover and stego picture as key information. to isolate the covered data in separating stage the stego-picture is added with key data. it also needs to supervise stego-key which it fabricates the multifaceted nature of applying filters. the major demerit of the proposed scheme is covering limit of high secret data. [20]. bailey et al. proposed stego shading cycle (scc) strategy for shading images that conceals information in various channels of the cover image in a cyclic way. the primary mystery bit is covered up in pixel1's red channel, the second mystery bit is covered up in the green channel of pixel2 and the third mystery bit is covered up in the blue channel of pixel3. the significant confinement in scc technique is that the mystery data is installed in cover image pixels in a settled cyclic and orderly way. so, aggressors can without much of a stretch find this strategy if mystery data from a couple of pixels is effectively separated [21]. gutub et al. proposed a high payload pixel pointer method (pit) what one channel is utilized as a marker and the other two channels are information channels. the proposed strategy shrouded the puzzle information in either of the information which shahid rahman (et al.), investigation of lsb based image steganographic techniques in spatial domain for secure communication (pp. 1 12) sukkur iba journal of emerging technologies sjet | volume 2 no. 1 january – june 2019 © sukkur iba university 6 directs in a predefined cyclic way. the provisional outcomes demonstrate the incredible limit and better delicate quality of the arranged calculation and furthermore dodge the key trade overhead. the major feeble purpose of this technique is that the payload limit is absolutely subject to have pictures and marker bits which can result in low payload. similarly, this method hides fixed numbers of bits in each pixel which can be brought more changes in the cover image if we embed a greater number of secret bits in each pixel. the major limitation in the proposed method is that the secret information can be extracted easily if an attacker finds out the algorithm being used for message hiding because secret data is in plain text form not encrypted. moreover, these methods result in stego images of low quality which can be detected using hvs [22]. karim et.al presented a new approach to enhance the security of the existing lsb substitution method by adding one extra barrier of the secret key. in the said method, secret key and red channel are used as an indicator while green and blue channels are data channels. basis of covered key bits and red channel lsbs the secret data bits are embedded either in green channel or in the blue channel. if either the bit of the red channel lsb or the secret key bit is 1, then the lsb of green channel is replaced with secret message bits otherwise lsb of blue channel is replaced by secret bit. although this approach possesses the same payload as lsb based approaches, it increases security by making the use of a secret key. an intruder cannot easily extract the secret information without the correct secret key [23]. muhammad et.al presents an ensured strategy for shading picture steganography using gray-level modification and multilevel encryption. the security of information between two social gatherings is noteworthy issue in this front-line area. to adjust these issues proposed plot is a viable procedure for rgb pictures in light of diminishing or dim dimension change gray level modification (glm) and staggered encryption (mle). the mystery key and secret information are encoded utilizing mle calculation before mapping it to the dark levels of the cover image. at this point, a transposition work is connected on cover image preceding information stowing away. the use of the transpose mystery key, mle, and glm includes four unique levels of security to the proposed calculation making it extremely troublesome for a vindictive client to extricate the first secret data. however, the proposed scheme provides a robust, efficient and time saving way to hide secret information inside the cover image. the main advantages of the proposed scheme improve quality of stego images, high imperceptibility, costeffectiveness, and enhanced robustness. moreover, the utilization of mle and image transposition adds multiple security levels to the said technique. the major shortcoming of this method is its vulnerability to different attacks (cropping, scaling and noise attacks) which exist in all spatial domain techniques including the existing five schemes. since the spatial domain is used in the proposed approach, the hidden data cannot be fully recovered if the image is compressed, scaled or attacked with noises [24]. f. a jassim et al proposed a protected strategy whose key thought depends on the way that adjoining pixels in pictures are firmly connected with one another. in fmm plot, the picture is isolated into various obstructs, every one of which contains k×k pixels where k demonstrates the window measure and every pixel speaks to a number in the range 0-255 distinct by 5 for 8-bit pictures. the proposed st-fmm strategy is better in power and accomplishes great nature of stego pictures. in any case, there is an exchange off between the payload and window size with the end goal that expands the window estimate diminishes the payload and the other way around [25]. wang, et al proposed a superb steganographic technique dependent on pixel value differencing (pvd) and modulus work, which is more secure against the different identification assault and performs superior to anything the pvd conspire. this plan expands the pinnacle motion (psnr) qualities to 44.15 db while disguised 51,219 bytes. it abuses the rest of the two continuous pixels to record the data of the inserted information. it accomplishes greater adaptability, fit for shahid rahman (et al.), investigation of lsb based image steganographic techniques in spatial domain for secure communication (pp. 1 12) sukkur iba journal of emerging technologies sjet | volume 2 no. 1 january – june 2019 © sukkur iba university 7 determining the ideal rest of the two pixels in any event mutilation. this strategy expands the psnr (up to 8.9%) more than the straightforward pvd technique. to keep up the distinction in a similar range when inserting process, this technique utilizes rearranging system to change the notice of the pixel combine [26]. joo, et al. exhibited an improvement on [32] technique by installing distinctive measures of mystery information depending on pixel-match intricacy. the test in this strategy demonstrates that the distinction histogram had a shape nearer to the cover picture which was difficult to be identified by histogram examination. despite the fact that this technique enhanced the issue of the shape in the distinction histograms. the inserting limit isn't higher than wang et al strategy, which is differing for the odd and even implanting zones [27]. chen et al presented a pvd strategy utilizing pixel pair matching (ppm). in this strategy, the cover-picture is apportioned into 2 × 2 inserting cells for installing by arbitrary implanting plans. to expand the arbitrary inserting trademark, two reference tables are made. this irregular system raises the security of the implanted information from discovery and different steganalysis assaults. the real commitments of this methodology are: (1) ppm was used subsequently a bigger number of information disguised than unique pvd, (2) effectively diminishing the tumbling offlimit issue of controlling just on pivot embedding unit (peu). (3) the mystery information was covered which was dependent on two reference tables which raised the irregular trademark and the visual quality. (4) this strategy is harder to be recognized for its distinction histogram. it shows that the estimations of the stego-picture are near the estimations of the cover-picture. chen plot altogether had higher limit and picture quality [28]. al dhamari et al proposed another square based steganographic calculation utilizing pvd and modulus work procedures, to be specific, mf-pvd. to assess the execution of mf-pvd calculation, they contrast it and six relevant conditions of-workmanship calculations, as an obvious truth, the proposed mf-pvd calculation is exceptional to these reference techniques in two fundamental highlights, the inserting limit and the security. actually, the security of calculation is high because of producing numerous stages and existing the separate extend table. the calculation's system can be stretched out to the rgb shading pictures for enhancing the ability of inserting. in addition, it may be a decent expansion to build up a methodology that considers the half breed area. so there are tentative arrangements to create modulus work based plans for other media, for example, sounds and video [29]. khan et al proposed a novel picture steganographic procedure (m-lsb-sm) for shading pictures with better indistinctness and security. a normal psnr of 47.93 db is registered more than one hundred and fifty pictures. the mystery data are separated into four sub-squares and is gone through mlea, which makes the assault on this calculation dreadful and therefore, deceives the procedure of steganalysis. this is the reason that their proposed plan is equipped for producing stego pictures of an adequate quality that satisfies the ideal requests of current security frameworks and clients. the calculation is straightforward, simple to execute and a decent blend of subtlety and security and therefore is more possible to be embraced by steganographic applications. still extra upgrades are feasible broadening mle calculation and payload capacity. table ii shows the analysis of different image steganographic techniques in spatial domain based on psnr in the range of 50-65. table iii shows the analysis of different image steganographic techniques in spatial domain based on psnr in the range of 45-50 table iv shows the analysis of different image steganographic techniques in spatial domain based on psnr in the range of 38-45. shahid rahman (et al.), investigation of lsb based image steganographic techniques in spatial domain for secure communication (pp. 1 12) sukkur iba journal of emerging technologies sjet | volume 2 no. 1 january – june 2019 © sukkur iba university 8 table ii: analysis of different image steganographic techniques in spatial domain based on psnr in the range of 50-65 s.no existing methods psnr values 1 khan et al method 2[36] 63.0034 2 khan et al method 1[24] 58.7344 3 karim's method[23] 52.2172 4 classic lsb method[7] 52.2416 5 scc method[27] 52.2023 6 channali et al [16] 51.9764 fig.3. psnr values of exsiting methods between 50-65 figure 3 shows the analysis of different image steganographic techniques in spatial domain based on psnr in the range of 50-65. it seems that khan et al method [36] having psnr value 63.0034 which dominate over all other methods, that show the visual quality of the image. table iii.: analysis of different image steganographic techniques in spatial domain based on psnr in the range of 45-50 s.no existing methods psnr values 1 hangling et al [15] 49.5545 2 wang et al [32] 49.2565 3 pit [11] 48.5249 4 mehdi et al [19] 48.2454 5 gutub et al [22] 47.4536 6 jung k h et al [17] 45.5677 fig. 4. psnr values of exsiting methods between 45-50 figure 4 shows the analysis of different image steganographic techniques in spatial domain based on psnr in the range of 45-50. it seems that hangling et al method [15] having psnr value 49.5545 which dominate over all other methods, that show the visual quality of the image. table iv: analysis of different image steganographic techniques in spatial domain based on psnr in the range of 38-45 s.no existing methods psnr values 1 f a jassm et al [25] 44.3455 2 baily et al [21] 43.3425 3 joo et al [33] 42.5352 4 yang et al [18] 42.4553 5 fmm[26] 41.294 4 6 al dhamari et al [35] 39.5676 fig.5. psnr values of exsiting methods between 38-45 shahid rahman (et al.), investigation of lsb based image steganographic techniques in spatial domain for secure communication (pp. 1 12) sukkur iba journal of emerging technologies sjet | volume 2 no. 1 january – june 2019 © sukkur iba university 9 figure 5 shows the analysis of different image steganographic techniques in spatial domain based on psnr in the range of 38-45. it seems that f a jassm et al method [25] having psnr value 44.3455 which dominates over all other methods, that show the visual quality of the image. table.v shows ciritical analysis up to eighteen methods with their advantages and disadvantages and also analyzed based on measuring alogrithm (capacity, robustness, perception, temp protection, computation) which is the basic criteria of steganography, which is also shown in table i. 3. conclusion and future work specialists have introduced different plans to adapt web security issues. in this specific situation, both steganography and cryptography can be utilized successfully. however, real restriction in the current steganographic techniques is the low-quality yield stego images, which subsequently brings about the absence of security. this paper provides an illustration of a number of steganographic methods; its significant kinds and arrangement of steganography in the recent couple of years have been proposed. we have dissected various proposed systems. it is demonstrated the visual nature of the image is corrupted when shrouded information expanded up as far as possible utilizing lsb based strategies. analysis of the truthful properties of commotion or visually investigation strategies can be broken or demonstrates significant adjustment of image. in this study, distinctive steganographic articles were contemplated and were ordered into various methods. the same numbers of new application zones are recognized like web managing an account, portable correspondence security, cloud security and so on. the understanding into the steganographic standards will certainly control us to recognize new zones and to enhance its applications in the effectively existing application regions also. acknowledgement the authors wish to thank every one of the supporters for their basic and specialized review of the proposed work and their important help and direction. the authors also gratefully acknowledge the helpful comments and suggestions of the reviewers. shahid rahman (et al.), investigation of lsb based image steganographic techniques in spatial domain for secure communication (pp. 1 12) sukkur iba journal of emerging technologies sjet | volume 2 no. 1 january – june 2019 © sukkur iba university 10 table v: investigation of different image steganography techniques in spatial domain sno domain techniques advantages disadvantages analysis based on c a p a c it y r o b u st n e ss p e r c e p ti o n t e m p p r o te c ti o n . c o m p u ta ti o n 1 spatial[15] pvd with adaptive lsb histogram of both original and stego image is always same for experimental results data sets is too small yes yes no no no 2 spatial[16] pattern bits combinations along with (stego-key) using lsb hidden data hidden capacity is low no no no no no 3 spatial[17] mpd with lsb same as pvd but on some level is valuable from common pvd methods limited data sets, and threshold, both sides stego key require yes yes no no no 4 spatial[18] dark area of image with lsb substitution helpful for smooth district with strong limit of object based dataset high calculation required and not tried on high surface zones no yes no no no 5 spatial[19] lsb substitution with random pixel selection safety of hidden message in stego-image implanting without thinking about graphic quality in arbitrary pixel determination no no no no no 6 spatial[20] lsb substitution with median filtering high hidden capacity computationally confusing (sifting ) in stego-key essential yes no no no no 7 spatial[21] stego colour cycle hiding data different channels embedding is a fixed cyclic and systematic way, easily can extracted if a few bit extracted yes no yes no no 8 spatial[22] pit high hidden data better imperceptibility shipment limit is absolutely reliant on host picture and pointer bits yes yes yes no no 9 spatial[23] lsb substitution replacement method high payload , better imperceptibility by adding one extra barrier of secret key increasing security depending on secret key can easily extracted without correct key yes yes yes no yes 10 spatial[24] glmodification and mle high imperceptibility, times saving and robustness vulnerability to different attacks (cropping, scaling and noise) no yes yes yes yes 11 spatial[31] hiding text in image using five modulus method achievement of robustness and good quality of stego images if increasing the window size then will be decrease payload yes no yes no no 12 spatial[32] pixel-esteem differencing and modulus work high capacity, and good image quality vulnerability to different attacks yes no yes no no 13 spatial[33] protecting pixel-esteem differencing histogram with modulus work enhanced security and perception transparency hidden data too low no yes yes no yes 14 spatial[34] histogram preserving using pixel pair matching higher limit and better quality vulnerability to different attacks yes no yes no yes 15 spatial[35] modulus function and pixel-value differencing embedding capacity and the security perception and vulnerability to different attacks(noise ,cropping) yes yes no no yes 16 spatial[36] mle and achromatic component of an image security and good imperceptibility visual quality, payload limit and vulnerability of statistical attacks no yes yes no yes 17 spatial[38] data mapping and lsb substitution embedding capacity and visual quality temper protection and computation yes yes yes no no 18 spatial [39] logistic map and secret key high security, payload, visual quality vulnerabilities(noise, copping) computation yes no yes yes no shahid rahman (et al.), investigation of lsb based image steganographic techniques in spatial domain for secure communication (pp. 1 12) sukkur iba journal of emerging technologies sjet | volume 2 no. 1 january – june 2019 © sukkur iba university 11 references [1] anderson, r. j., & petitcolas, f. a. (1998). on the limits of steganography. ieee journal on selected areas in communications, 16(4), 474-481. [2] i. diop, s. farss, k. tall, p. fall, m. diouf, and a. diop, "adaptive steganography scheme based on ldpc codes," in advanced communication technology (icact), 2014 16th international conference on, 2014, pp. 162-166. [3] pfitzmann, b. (1996, may). information hiding terminology-results of an informal plenary meeting and additional proposals. in proceedings of the first international workshop on information hiding (pp. 347-350). springer-verlag. [4] johnson, n. f., & jajodia, s. (1998). exploring steganography: seeing the unseen. computer, 31(2). [5] ker, a. d. (2005). steganalysis of lsb matching in grayscale images. ieee signal processing letters, 12(6), 441-444. [6] kour, j., & verma, d. (2014). steganography techniques–a review paper. international journal of emerging research in management &technology issn, 2278-9359. [7] a. sharp, q. qi, y. yang, d. peng, and h. sharif, "a video steganography attack using multi-dimensional discrete spring transform," in signal and image processing applications (icsipa), 2013 ieee international conference on, 2013, pp. 182-186. [8] hu, s. d. (2011, august). a novel video steganography based on non-uniform rectangular partition. in the 14th ieee international conference on computational science and engineering (pp. 57-61). ieee. [9] johnson, n. f., & jajodia, s. (1998). exploring steganography: seeing the unseen. computer, 31(2).. [10] lin, e. t., & delp, e. j. (1999, april). a review of data hiding in digital images. in pics (vol. 299, pp. 274-278). [11] johnson, n. f., & katzenbeisser, s. (2000). a survey of steganographic techniques. in information hiding (pp. 4378). [12] reddy, h. m., & raja, k. b. (2009). high capacity and security steganography using discrete wavelet transform. international journal of computer science and security (ijcss), 3(6), 462. [13] aos, a. z., naji, a. w., hameed, s. a., othman, f., & zaidan, b. b. (2009, april). approved undetectable-antivirus steganography for multimedia information in pe-file. in computer science and information technologyspring conference, 2009. iacsitsc'09. international association of(pp. 437-441). ieee. [14] kruus, p., scace, c., heyman, m., & mundy, m. (2003). a survey of steganography techniques for image files. advanced security research journal.[on line], 5(1), 41-52. [15] hanling, z., guangzhi, g., & caiqiong, x. (2009, may). image steganography using pixel-value differencing. in electronic commerce and security, 2009. isecs'09. second international symposium on (vol. 2, pp. 109-112). ieee.. [16] channalli, s., & jadhav, a. (2009). steganography an art of hiding data. arxiv preprint arxiv:0912.2319. [17] jung, k. h., ha, k. j., & yoo, k. y. (2008, august). image data hiding method based on multi-pixel differencing and lsb substitution methods. in convergence and hybrid information technology, 2008. ichit'08. international conference on (pp. 355-358). ieee. [18] yang, c. h., weng, c. y., wang, s. j., & sun, h. m. (2008). adaptive data hiding in edge areas of images with spatial lsb domain systems. ieee transactions on information forensics and security, 3(3), 488-497.. [19] islam, a. u., khalid, f., shah, m., khan, z., mahmood, t., khan, a., ... & naeem, m. (2016, august). an improved image steganography technique based on msb using bit differencing. in innovative computing technology (intech), 2016 sixth international conference on (pp. 265-269). ieee. [20] chen, w. j., chang, c. c., & le, t. h. n. (2010). high payload steganography mechanism using hybrid edge detector. expert systems with applications, 37(4), 3292-3301.. [21] motameni, h., norouzi, m., jahandar, m., & hatami, a. (2007). labeling method in steganography. world academy of science, engineering and technology, 24, 349-354... [22] viswanatham, v. m., & manikonda, j. (2010). a novel technique for embedding data in spatial domain. international journal on computer science and engineering, ijcse, 2(2010).... [23] yang, h., sun, x., & sun, g. (2009). a high-capacity image data hiding scheme using adaptive lsb shahid rahman (et al.), investigation of lsb based image steganographic techniques in spatial domain for secure communication (pp. 1 12) sukkur iba journal of emerging technologies sjet | volume 2 no. 1 january – june 2019 © sukkur iba university 12 substitution. radioengineering, 18(4), 509-516. [24] parvez, m. t., & gutub, a. a. a. (2008, december). rgb intensity based variablebits image steganography. in asia-pacific services computing conference, 2008. apscc'08. ieee (pp. 1322-1327). ieee. [25] f. a. jassim, “a novel steganography algorithm for hiding text in image using five modulus method,” arxiv preprint arxiv:1307.0642, 2013. article (crossref link) [26] wang, c. m., wu, n. i., tsai, c. s., & hwang, m. s. (2008). a high quality steganographic method with pixel-value differencing and modulus function. journal of systems and software, 81(1), 150-158.. [27] joo,j. c., lee, h. y., & lee, h. k. (2010). improved steganographic method preserving pixel-value differencing histogram with modulus function. eurasip journal on advances in signal processing, 2010(1), 249826. [28] chen, j. (2014). a pvd-based data hiding method with histogram preserving using pixel pair matching. signal processing: image communication, 29(3), 375-384. [29] al-dhamari, a. k., & darabkh, k. a. (2017). block-based steganographic algorithm using modulus function and pixel-value differencing. journal of software engineering and applications, 10(01), 56. [33] muhammad, k., ahmad, j., farman, h., jan, z., sajjad, m., & baik, s. w. (2015). a secure method for color image steganography using gray-level modification and multi-level encryption. tiis, 9(5), 1938-1962.. [34] zakaria, a., hussain, m., wahab, a., idris, m., abdullah, n., & jung, k. h. (2018). high-capacity image steganography with minimum modified bits based on data mapping and lsb substitution. applied sciences, 8(11), 2199. [35] majeed, a., mat kiah, m. l., madhloom, h. t., zaidan, b. b., & zaidan, a. a. (2009). novel approach for high secure and high rate data hidden in the image using image texture analysis. international journal of engineering and technology, 1(2), 63-69.. [36] muhammad, k., sajjad, m., mehmood, i., rho, s., & baik, s. w. (2016). a novel magic lsb substitution method (m-lsbsm) using multi-level encryption and achromatic component of an image. multimedia tools and applications, 75(22), 14867-14893. [37] solanki, r., chuahan, m., & desai, m. survey of image steganography techniques.. [38] bandhyopadhyay, a., dey, d., pal, r. k., & maji, a. k. (2018). an indirect addressing image steganographic scheme using 9× 9 sudoku matrix. in proceedings of the international conference on computing and communication systems (pp. 689-703). springer, singapore. [39] ulker, m., & arslan, b. (2018, march). a novel secure model: image steganography with logistic map and secret key. in digital forensic and security (isdfs), 2018 6th international symposium on (pp. 1-5). ieee. [40] liao, x., yin, j., guo, s., li, x., & sangaiah, a. k. (2018). medical jpeg image steganography based on preserving inter-block dependencies. computers & electrical engineering, 67, 320-329. vol. 1, no. 1 | january june 2018 sjet | issn: 2616-7069 | vol. 1 | no. 1 | © 2018 sukkur iba 51 estimating news coverage patterns using latent dirichlet allocation (lda) batool zehra1,naeem ahmed mahoto1,vijdan khalique1 abstract: the growing rate of unstructured textual data has made an open challenge for the knowledge discovery which aims extracting desired information from large collection of data. this study presents a system to derive news coverage patterns with the help of probabilistic model – latent dirichlet allocation. pattern is an arrangement of words within collected data that more likely appear together in certain context. the news coverage patterns have been computed as number function of news articles comprising of such patterns. a prototype, as a proof, has been developed to estimate the news coverage patterns for a newspaper – the dawn. analyzing the news coverage patterns from different aspects has been carried out using multidimensional data model. further, the extracted news coverage patterns are illustrated by visual graphs to yield in-depth understanding of the topics which have been covered in the news. the results also assist in identification of schema related to newspaper and journalists’ articles. keywords: news coverage pattern; probabilistic model; data visualization; multidimensional data model. 1. introduction the rapid growth of the web technologies has resulted in number of websites. according to statistics, there are 1800,047,111 active websites recorded in 2017 [1]. that means, tremendous volume of data is produced on these websites, which paves the way for information processing in order to extract knowledge and meaningful patterns. it can assist in decision-making regarding a number of scenarios and problems. out of total number of active websites, there are many e-news websites with a large share of visitors who regularly check news and read articles on these websites. for example, in us, around 70% of the population 1 mehran university of engineering and technology, jamshoro, pakistan corresponding email: sayyid_zehra@yahoo.com refer to the internet for keeping up-to-date with news [2]. in addition, a large number of news articles are published on the daily basis covering various current topics. there exists a huge platform that can be explored with modern computing and data processing tools to find out interesting and useful knowledge. in this research study, useful knowledge is extracted from the e-newspaper articles to obtain the news coverage patterns. news coverage pattern refers to finding issues or topics being discussed over a certain period of time. the aim is to find out the coverage given to a specific topic or issue in news. the coverage patterns would reveal that what topics or issues remained under discussed and trending subject in a newspaper. the news mailto:sayyid_zehra@yahoo.com batool zehra (et al.), estimating news coverage patterns using latent dirichlit allocation (lda) (pp. 51 56) sukkur iba journal of emerging technologies sjet | volume 1 no. 1 january – june 2018 © sukkur iba university 52 coverage patterns have been obtained by means of latent dirichlet allocation (lda), which is a probabilistic model for collection of discrete data [3]. lda is a modeling technique, which automatically develops topics based on patterns of co-occurrence of words. lda finds out a set of ideas or themes that well describe the entire corpus. the scope of this research is focused on the daily news and newspaper articles published on the website of a popular newspaper-the dawn. during the course of this research, an application prototype as the proof of concept has been developed that performs the task of estimating the news coverage patterns. text mining and analysis is performed to check coverage of certain news. precisely, the goal of this research is to identify and highlight the topics or issues under discussion in numerous articles of the dawn newspaper. furthermore, the trending topics are statistically represented as knowledge to end-users. the information visualization has been considered an emerging field for the several application domains; for instance, structural information by injecting parameters of location has been represented in visual formats [7]. the paper is organized as follows: related studies are discussed in section 2; the working principle of extracting news coverage patterns is reported in section 3; the outcomes of the study are described in the discussion section 4; finally, section 5 presents conclusions. 2. literature maintaining the integrity of the specifications reference [4] described way to utilize lda to journalism. the study [5] evaluated two novel approaches, one by using a video stream and second by using the closed caption stream. an lda approach has been used to detect the text stream and the person shots. the research concluded that the individual system gave comparable results, however; a combination of the two systems provided a significant improvement as compared to the individual system. reference [6] treated groups of objects together as spatial visual words and investigated configurations of regions using lda and invariant descriptors. in this research, computation of invariant spatial signatures for pairs of objects was based on a measure of their interaction inside the scene. a simple classification was used to define spatial visual words to extract new patterns of similar object configurations. the modeling of the scene into a finite mixture was in accordance with the spatial visual words by the use of latent dirichlet model. statistical analysis was done to better understand the spatial distributions inside the discovered semantic classes. one case study for synthetic imagery and for real imagery was experimented using lda and the results proved that this model has good performances with the small amount of training data. it has been concluded that scene level analysis can be done through lda with minimal human interaction leaving behind the traditional approaches of pixel or region level analysis [6]. the reference [8] unearthed significant components, for instance, nouns and verbs given broadcast transcript. it further computed weights of components with the help of their frequency in the text. the study under consideration applies lda in order to get news patterns for better understanding of trends of news topics/issues. 3. news coverage patterns extraction workflow the workflow of identifying news coverage patterns is explained in this section that comprises of four steps. the steps are explained in the order of their execution as illustrated in fig. 1. the workflow intends to find out the coverage of various issues/topics in multiple news articles and news. following are the steps and their explanations. 3.1. web crawler the primary source of data is online news websites. in order to fetch data from these websites, a crawler has been designed and batool zehra (et al.), estimating news coverage patterns using latent dirichlit allocation (lda) (pp. 51 56) sukkur iba journal of emerging technologies sjet | volume 1 no. 1 january – june 2018 © sukkur iba university 53 developed. however, crawler targeted only one website – the dawn (www.dawn.com). the crawler gathered daily news and news articles, which needed preprocessing before determining news coverage patterns. these collected news and news articles are stored in documents referred to as document database or corpus. 3.2. data collection and preprocessing preprocessing stage involves the rectification of data such that the subsequent processes can be done. the refinement of data leads to better results, since unnecessary data gets removed and useful data elements are left behind. the data refinement procedure during preprocessing performs activities: tokenization, stop word removal, stemming and vector space model. 3.2.1. tokenization tokenization is the process to partition the sentences contained in the textual data into its tokens (i.e., words). for example, consider a sentence ‘this study aims at extracting news coverage patterns’; the tokenization results into tokens: {‘this’, ‘study’, ‘aims’, ‘at’, ‘extracting’, ‘news’, ‘coverage’, ‘patterns’}. 3.2.2. stop word removal news and articles are read one-by-one by the system. the system removes stop words from the given document. stop words are commonly used words in language such as is, at, a, on, of etc. their presence can mislead the text search and text analysis. therefore, stop words are removed from text during preprocessing stage. 3.2.3. stemming in the next stage of preprocessing, stemming takes place. stemming is the procedure of determining the base word or root word of a given word. for example, extract is the root word of extracting. during stemming, each word is traced to its basic root word. this is an important process as it can help remove noise from data. 3.2.4. vector space model vector space model represents text documents as vectors. vector(s) corresponds to the dimension of the vector space. the text data of news and news articles has been represented in the form of bag-of-words. fig. 1. workflow of news pattern extraction and visualization. 3.3. news pattern extraction news pattern extraction refers identifying patterns about coverage of certain topics in news and articles. lda finds out what topics are discussed in a given article by observing processed news data (i.e., vector space model – bag-of-words) and produces a topic distribution. a prototype application developed in this study has implemented lda for the news coverage pattern extraction. latent dirichlet allocation (lda) – lda algorithm reported in [3] presents the mathematical model. the principle concept of lda describes that documents’ database (or corpus) contains words referring to latent topics and thus relate to the overall theme of the documents. batool zehra (et al.), estimating news coverage patterns using latent dirichlit allocation (lda) (pp. 51 56) sukkur iba journal of emerging technologies sjet | volume 1 no. 1 january – june 2018 © sukkur iba university 54 consider a set of m documents’ database (dd) or corpus such that dd = {d 1 ,d 2 ,...,d m } ∑ 𝑛 = {𝑝1 , … , 𝑝𝑘 }, where di represents set of documents in the corpus dd and each document d is a vector of n comprises of words wi such that d = {w 1 ,w 2 ,...,w n } . lda accomplishes steps as reported below for each w in corpus dd. i. select n from poisson probability (ξ) ii. select q from dir( a ), where a shows per-document topic distribution iii. for each of the n words wn: a. select a topic zn ∼ multinomial(θ) b. select a word wn from p(w n | z n , b), a multinomial probability conditioned on topic zn; b ij = p(w j = 1| z i = 1) probability of wn towards the topic zn having parameters a , b , the joint distribution of a topic mixture q , a set of n topics z, and a set of n words w is given by: p(q,z,w | a, b) = p(q | a) p(z n |q )p(w n | z n , b) n=1 n õ 3.4. news pattern extraction visualization is the final output of this study. the extracted news patterns are presented statistically using graphs, line charts and bar charts. the statistical representation gives a comprehensive view of how certain topics are discussed in news and articles in a newspaper. 4. discussion lda helps to find the main theme of an article and discover the coverage of specific news theme. the discovered theme is then chronologically ordered and presented in this section as bar graphs and line charts in order to show the trend of various patterns of news issues and topics. figure 2 and 3 show the trends of topics mentioned in newspaper. these topics are frequently discussed and have been in news for the given period of time. the frequencies are plotted on y-axis while x-axis possesses timings. each topic has its own line with different colors to indicate the change in trends. for instance, the topic named nab in fig. 2 remained top in news during 15 days. similarly, trends about corruption and politicians have been the most frequent topics during the given dates. it can also be observed that these topics have almost similar trend with slight variations. this trend leads to understanding the media coverage in newspapers. in other words, media targets news about nab, corruption and politicians. the similar trends are depicted in fig. 3. in fig. 4, the topics (i.e. army, military, pakistan) discussed in news articles by different columnist of the dawn newspaper are depicted. the topics being covered by these writers show a trend of certain issues. these trends represent that who among the considered writers focuses which of the issues and topics in their writings. fig. 2. news coverage trend of 3 topics 15 days. batool zehra (et al.), estimating news coverage patterns using latent dirichlit allocation (lda) (pp. 51 56) sukkur iba journal of emerging technologies sjet | volume 1 no. 1 january – june 2018 © sukkur iba university 55 fig. 3. number of news regarding certain topics. for example, referring to fig. 4, cyril almeida mostly talked about pakistan, military and army in his news articles. these news coverage patterns and topics covered by the writers in their writings clearly yield the direction and mindset of the media personnel, since media has been considered as opinion maker for the societies. fig. 5 provides information regarding available collected news and news articles in the database. the prototype application offers to search for the topics or terms in the specified range of time within news or in news articles of columnists. fig. 4. frequency of topics covered in articles written by news analysts. for instance, fig. 6 represents that term ppp (pakistan people’s party) has been trending more in the news on 5th march 2017 as compared with rest of the days of march 2017 in the available database of the prototype application. the news coverage patterns and their trend helps in understanding the behavior and mindset of media personnel, who play an essential role in building opinions of the people. the patterns not only will serve government officials to have in-depth information about directions of media and its agenda. likewise, the writings of certain columnists will help in understanding the targets and their priorities in building the nation. fig. 5. the news and news articles in the corpus. fig. 6. term ppp (pakistan people party) coverage trend. batool zehra (et al.), estimating news coverage patterns using latent dirichlit allocation (lda) (pp. 51 56) sukkur iba journal of emerging technologies sjet | volume 1 no. 1 january – june 2018 © sukkur iba university 56 5. conclusion this paper presents an approach to apply probabilistic topic model (i.e., lda) in finding significant patterns from newspapers. the data, crawled from the dawn newspaper’s official website, has been processed to uncover the news coverage in certain time limits. to validate the potential of understanding news coverage patterns, a prototype application has been built, which performed the necessary steps to reveal the patterns. these patterns have been presented with the help of visualization methods. it has become a fact that media influences perception of general public and mold their sentiments and thinking about certain issues and events. this research would assist in identifying the narrative of media groups regarding certain issues and events. the point of view of article writers can be stipulated by applying the analytical approach presented in this study. consequently, the inclination of a newspaper can be judged based on the coverage they are giving to various issues. the in-depth knowledge about media groups and their news coverage patterns may assist government authorities like pemra (pakistan electronic media regulatory authority) to regulate the electronic print media. as future works, we plan to compare the applied approach with the state-of-the-art methods and included other newspapers as well as research articles to determine the topical coverage of the scientific research articles. references [1] d. s. fowler, “tek eye how many websites are there in the world?,” online: tekeye.uk/computing/how-manywebsites-are-there (accessed 30-12018). [2] fuller, steve, “topic: news industry”, online: www.statista.com/topics/1640/news/ (accessed 20-1-2018). [3] d. m. blei, y. ng. andrew, and michael i. jordan, "latent dirichlet allocation," journal of machine learning research, pp. 993-1022, jan 2003. [4] c. jacobi, w. v. atteveldt, and k. welbers, “quantitative analysis of large amounts of journalistic texts using topic modelling”, digital journalism, vol. 4, no. 1, pp. 89-106, 2016. [5] h. misra, f. hopfgartner, a. goual, p. punitha, and j. m. jose, “news story segementation based on semantic coherence and content similiarity”, in mmm, pp.347-357, january 2010. [6] c. vaduva, i. gavat, and m. datcu, “latent dirichlet allocation for spatial analysis of satellite images,” ieee transactions on geoscience and remote sensing, vol. 5, no. 15, pp. 2770-2786, 2013. [7] s. shah, v. khalique, s. saddar, and n. a. mahoto, “a framework for visual representation of crime information,” in indian journal of science and technology, vol. 10, no. 40, pp. 1-8. issn: 0974-6846, 2017. [8] m. j. pickering, l. wong, and s. r¨uger, “anses: summarisation of news video,” image and video retrieval, lncs 2728, pp.425-434, 2013. http://www.statista.com/topics/1640/news/ format template vol. 1, no. 2 | july december 2018 sjet | issn: 2616-7069 | vol. 1 | no. 2 © 2018 sukkur iba 12 design and control of unmanned underwater vehicle rehan akbar1, syed raza mehdi2, aijaz akhtar1, bharat lal1 faizan3, nooruddin khaskheli4, kamran shahani2 abstract: unmanned underwater vehicles (uuv) are the robots that are used to monitor underwater environment at remote distance, either for inspection of underwater wreckage or for surveillance of underwater environment. any such robot due to harshness of environment conditions needs a robust watertight design and requires various sensors for effective environment monitoring. the entire uuv structure is comprised of the vehicle, which is linked with operators on top of the surface by a set of cables that hold relevant cables for data and power communication. in this context, a lightweight underwater vehicle was designed using pvc (polyvinyl chloride) pipes and equipped with brushless dc motors, electronic speed controller, relay module, sonar, claw arm and camera. it can navigate in six directions (up, down, left, right, forward, backward) and camera allows underwater surveillance of the environment, with sonar helping to indicate the target depth. the designed uuv can also perform basic pick and place task using a claw arm and is remotely operated using a joystick controller. overall, the designed uuv prototype has shown its potential capabilities for underwater surveillance and environment monitoring through practical demonstrations. keywords: automation; rov; sonar; joystick; manipulator;arduino. 1. introduction the inventions of the uuv’s were designed for underwater surveillance and to explore underwater life. it is widely used by navy for underwater inspection and it is also widely used by civilians in oil industries. sometimes it’s also known as underwater drones. such vehicles can act as the eyes of undersea fleet. these are most recent demonstration of such vehicles, replacing divers to do work in the ocean. these vehicles, 1 department of electrical engineering, isra university hyderabad, pakistan 2 ocean optics and automation lab, institute of ocean technology, ocean college, zhejiang university hangzhou 310058, china 3 institute of marine robotics, ocean college, zhejiang university; 4 institute of coastal engineering, ocean college, zhejiang university; corresponding author: kamranshahani@zju.edu.cn also known as deep submergence vehicles (dsvs), were designed to go deeper than divers. these were configured for ocean exploration, science, rescue, and survey [1, 2]. it is fundamentally a tethered submerged vehicle which consent the robots functioning to continue in comfy surroundings although it works in the perilous surroundings below. the entire uuv structure is linked with operators on the facade by a set of cables that lug electrical power, video and information signals reverse and forward among the rehan akbar (et al.), design and control of unmanned underwater vehicle (pp. 12 18) sukkur iba journal of emerging technologies sjet | volume 1 no. 2 july – december 2018 © sukkur iba university 13 machinist and the vehicle. uuvs are relatively small, tethered, and unmanned vehicle that are able to work solely underwater within the handled and sustained ability [4]. unmanned underwater vehicle varies in design modeling according to the desired operational depth and task. mainly autonomous underwater vehicles (auvs) can be able to function near 200 m or consequently, with a little working ahead of 5000 m. autosub-2 of the uk is usual of the intend of lots of auvs. long-range gliders (simonetti, 1998) can also be considered as auvs, although for the purposes of these review they are excluded because of the high power and payload-space requirements of current auditory instruments; gliders as well have limited straight actions which would build logical surveying challenges [5]. due to the huge technical improvements obtained in past decade, it is probable to utilize robot’s vehicle for undersea examination. in this approach, remotely operated vehicles (rovs) have been used carefully in the investigation of subsea phenomena as well as in the assemblage, examination and repair of offshore structures. throughout the completion of a firm task with the robotic vehicle, the operator needs to observe and manage a number of parameter. if, for example, the adjustment to the position of rov are made automatically, the precision will be greatly increased as compared to an observer controlling it manually [7-10]. this paper present the design of a uuv through an innovative display of thrusters with dynamical planned system in desire to be used in replication and manipulative of controllers. finally, design and structure of prototype of the planned uuv, with brushless dc motors arrangement of the current work is presented. the compensation of using a proper arrangement of brushless dc motors is scheduled as under [3]. reducing the number of required motors, at least six motors through propeller are essential to manage the uuv in its six degrees of freedom (dof), while by brushless dc motors just three or utmost four dc brushless motors are essential in order to give the essential pressure. materials inventory of latest assembly being used in autonomous submerged robots will persistently increase. in addition, aluminum with carbon fiber can be utilized for such deep sea vehicles. in this prototype the pvc (polyvinyl chloride) pipes are used in the assembly. these materials permit the uuv to be both lightweight and neutral buoyant, and to resist opposing friction. an example of underwater vehicle with similar materials is deep glider, capable to submerge up to 6 km [4]. 2. control system the control system designed for this uuv is simple and low cost. the vehicle is controlled on the front end by a ps2 joystick programmed with arduino nano as a master controller, which includes electronic components such as power regulators, live screen, battery bank and interfacing keys. master controller via tether using serial communication (i2c) controls the slave controller. the designed assembly of uuv lying on simple design reduces drag, which improves the underwater manipulative performance of the vehicle. a proportional integration and derivation (pid) controller has been implemented effectively in this approach. the control system provides the controllable and desired thrust power to the designed vehicle. different control methods of unmanned submerged vehicle are shown in table i. table i. control methods with restriction control method limitations pid can’t energetically recompense instead un-modeled robot’s hydraulics forces or indefinite instability constraint design opposing among response speed and overshoot control descendi ng form might effortlessly escort to system consequence manage precision fuzzy difficult to adjust the fuzzy system. overshoot prophecy instant not curved neural network can’t assemble the necessity of quick reaction multifaceted for real time application rehan akbar (et al.), design and control of unmanned underwater vehicle (pp. 12 18) sukkur iba journal of emerging technologies sjet | volume 1 no. 2 july – december 2018 © sukkur iba university 14 2.1. uuv modelling under actuated condition the thrusters are assembled in a design to provide the required drift to the vehicle. the open frame of the vehicle provides the best water flow, reducing the drag. below actuated conditions is described as one having less control inputs than degree of freedom. here some under actuated system, they require of actuation on definite guidelines or depth can be interpreted as constraints on the acceleration. for uuv, under actuated circumstance means when one or more of thrusters break down. the capability of to sustain a definite path or depth in its operation is address will be having two thrusters used for depth control. if one of thruster breaks down, the second thrusters will take over the control. the thrusters are having the 12 v to each. fig.1. thruster configuration (a) top view of thruster (b) front view of thruster (c) bottom view of thrusters (d) left view thruster (e) right view of thrusters. 2.2. master and slave controller tether the designed system is tethered through channel and remotely operates through an operative. yoke material flanked by tether and wire design will be one of difficulty in solidity of system. most of the systems entail a wire to convey the signal, video feedback, input voltage, and communication operator to the submerged vehicle. this will be attached stack to submerged vehicle consignment, which are shown in figure 2. the vehicle dimension, mass, working deepness, motors (thruster), subsystem, power, signal, power essential and pick and place is the constraint is must regard as in scheming. here are two common types instead of wire; one is the umbilical cable and the second is tether cable. normal rov used an electromechanical cable. b a c e d rehan akbar (et al.), design and control of unmanned underwater vehicle (pp. 12 18) sukkur iba journal of emerging technologies sjet | volume 1 no. 2 july – december 2018 © sukkur iba university 15 fig .2. working of tethered uuv in testing tank. this wire, in fact, will be achieved the mechanics and solidity of uuv. so how we can decrease the dimension of wire for uuv application. during function in submerged is energized through the battery within the uuv, although dc brushless motor and live video feedback were energized through battery which is place at the surface. examination, exploring and video feedback is essential part of technology. 2.3. difficulties the unmanned underwater vehicle robotic system is characterized by the need for working in a difficult underwater environment. any such robot need to handle various problems to function efficiently and effectively, such as waterproofing of the equipment, buoyancy of the vehicle in the water, communication and controlling of the vehicle in the water and navigation in different directions. we have overcome these problems by balancing the vehicle by adding dummy weight to the vehicle to minimize the buoyancy problem. to prevail overcome the problem of waterproof equipments, we made a water-proof box in which the circuitry of vehicle is placed to prevent it from water. we eliminated the problem of controlling servo motor by increasing its voltage. 2.4. controlling of uuv the play station 2 controller is a pleasant economical control interface by additional buttons and controls that are necessary for this project. resembling the preceding editions of the rov (remotely operated vehicle) control sketches, the ps2 controller is used for controlling equipment on the uuv such as the motors, motor direction, claw arm, and camera, as well as this prototype individual able to give the live video displayed on the topside station's lcd display. fig. 3. connection diagram of master controller. figure 3 shows the connection diagram of master controller. in adding to the ps2 controller, the topside station makes use of an arduino nano and a video lcd display. a buck converter is used to provide a 5v to the command and attention pins of the ps2 controller and 12 v to lcd display, the command pin of ps2 is connected to pin d11 of the arduino pin gnd is connect to gnd pin 3.3v to 3v3, clock pin is connect to d13 of the arduino respectively. rehan akbar (et al.), design and control of unmanned underwater vehicle (pp. 12 18) sukkur iba journal of emerging technologies sjet | volume 1 no. 2 july – december 2018 © sukkur iba university 16 fig.4.(a) connection diagram of slave controller (b) connection diagram of thruster and relay module. fig. 4(a) shows the connection diagram of the salve controller and the connection of dc brushless motor also the connection of claw arm. the thrusters are connected to relay module, then the relay module is connected to the electronic speed controller (esc). fig. 4(b) shows the connection of thrusters and relay module. the electronic circuit for the uuv is moderately uncomplicated because the majority of it is concerned with concerning fairly complicated equipment such as the speed controllers to the different pins on the arduino. at this stage the board for the circuits is just paved collectively on veroboard. formerly the circuit drawing as developed a appropriate circuit board will be developed. 2.5. working principle complete system operation is shown in system flow chart in fig. 5 when user apply the instruction to the master controller through ps2 controller which are connected to the master controller and connection is shown in fig. 5, the system transmits the signal to the slave controller, with the salve controller the dc brushless motors are connected and servo motor of claw arm also connected. after receiving the signal from master controller, slave controller executes the function of the input signal which gives the feedback to the master controller. the input signal can be any which are defined already in programming that can perform the tasks like picking and placing the objects through claw arm, can also optimize the live feedback through camera and can also performs the task to move the vehicle in six directions. fig. 5. flow chart of uuv a b rehan akbar (et al.), design and control of unmanned underwater vehicle (pp. 12 18) sukkur iba journal of emerging technologies sjet | volume 1 no. 2 july – december 2018 © sukkur iba university 17 3. results and discussion throughout the working on uuv towards the completion of final prototype, it has been observed that the behavior of uuv was as per requirement. the designed system worked accurately as per desired depth. the movement of claw arm which worked in direction of x-axis and camera, which moved in the direction of y-axis were accurate.it is used for underwater surveillance, inspection and for object recovery. it is the same as submarine but it has small size, low power consumption and low cost so it is more efficient. initially the design system was not more efficient and functionally strong, which only works in four directions, there was no camera for live video feedback, no sonar for measuring its depth and no claw arm for picking and placing the objects. but in designed system is adding all these components which make it more efficient. the design vehicle is prototype model which performs all functions as described above. fig. 6 shows the pulse width modulation (pwm) wave when we give the voltage to thrusters. the table ii shows the characteristic of the prototype of unmanned underwater vehicle (uuv). fig.6. shows the pwm of thrusters table ii. characteristics of uuv specifications explanation nominal speed 0.8km/h maximum speed 1.5km/h camera resolution 12 mp, 1080p degree of freedom 3 rated voltage 12v operating depth 5m 4. conclusion the final designed unmanned underwater vehicle has been demonstrated to be performing well and the developed uuv is remotely operated through a joystick controller and is able to perform inspections and surveillance of underwater environment efficiently. the uuv is well designed; it is waterproof, protecting the relevant equipment and sensors from water. the main tasks that it can perform are: navigation in six directions; up, down, left, right, forward and backward, imaging and visual monitoring of environment through camera and performing basic pick and place tasks using the claw arm. however, the final designed and developed has some limitations; for example, it can work up to 5 meters depth and communication is through cables only. its manipulability capabilities are limited and require further sensors to effectively monitor underwater environment. 5. future recommendation above mentioned limitations can be overcome by adding autonomous control system. the arm complexity will be increased, which is currently limited by platform payload capacity and increase the depth range, pressure sensor to determine the operating depth, temperature sensor, leakage sensor and infrared sensors for thermal imaging. rehan akbar (et al.), design and control of unmanned underwater vehicle (pp. 12 18) sukkur iba journal of emerging technologies sjet | volume 1 no. 2 july – december 2018 © sukkur iba university 18 references [1] paul g fernandes, pete stevenson, and andrew s brierley, “autonomous underwater vehicles: future platforms for fisheries acoustics,” ices journal of marine science, volume 60, pages 684–691, 1 january 2003. [2] wallace m. bessa, max s. dutra, and edwin kreuzer, “depth control of remotely operated underwater vehicles using an adaptive fuzzy sliding mode controller”, pp. 670–677, 26 november 2007. [3] ehsan zakeri, said farahat and seyed alireza moezi, “robust sliding mode control of a mini unmanned underwater vehicle equipped with a new arrangement of water jet propulsions simulation and experimental study” applied ocean research, pp. 521–542, 2 june 2016. [4] salimzhan a. gafurov and evgeniy v. klochkov, “autonomous unmanned underwater vehicles development tendencies”, pp. 141 – 148. [5] othman m.n and abdullah,s.s “problem identification for underwater remotely operated vehicle”, pp. 554 – 560, 2012. [6] kumar sandeep jain, sultan mohammad, and suyog bora, “autonomous underwater vehicle”, electronics and communication, department vivekananda institute of technology (east) jaipur, india, february-2015. [7] mallios angelos, ridao pere, marc carreras and hern´andez emili, “ navigating and mapping with the sparus auv in a natural and unstructured underwater environment”, campus de montilivi, 17071, girona, spain, january 2012. [8] hardy tim and barlow gavin, “unmanned underwater vehicle deployment and retrieval considerations for submarines”, inec in hamburg, germany, april 2008. [9] norihide wakita and kiyoshi hirokawa, “development of autonomous underwater vehicle (auv) for exploring deep sea marine mineral resources”, september 2010. [10] natural resource consultants, “remote operated vehicle deep-water crab pot removal feasibility study” seattle, washington 98119-1650, u.s.a, september 5, 2008 [11] l. miller, d. toal and e. omerdic, “low cost navigation for unmanned underwater vehicles using line of soundings” 2012, pages 63-68. [12] antonio fasano, francesco ferracuti and alessandro freddi, “a virtual thruster-based failure tolerant control scheme for underwater vehicles” universit`a campus bio-medico, rome, italy ifac-papersonline, volume 48, issue 16, 2015, pages 146-151. javascript:; vol. 1, no. 1 | january june 2018 sjet | issn: 2616-7069 | vol. 1 | no. 1 | © 2018 sukkur iba 27 low loss transmission circular polarizer for ku band application farman ali mangi1, nafessa shahani2, deedar ali jamro1 abstract: low loss transmission circular polarizer is proposed for ku band applications. the designed structure consists of two closely cross metallic strips which are based on fss for 15.25 ghz and 15.28 ghz applications. the right hand circular polarization (rhcp) and left handed circular polarization (lhcp) are obtained at 15.25 ghz and at 15.28 ghz. the transmission loss through polarizer is important issue for high frequency applications. due to transmission loss, new techniques are required to reduce the transmission loss of transmitted wave and achieve pure circular polarization. meanwhile, low loss transmission has been achieved by using dual layer of strips to obtain perfect circular polarization at certain mentioned resonant frequencies. theoretically, it is found that the outgoing waves through polarizer are perfect circular polarization at the distinct frequency ranges. keywords: polarizer; circular polarization; frequency selective surface; quarter wave plate; metamaterial. 1. introduction in modern microwave communication, circular polarization has received great interest in recent years. precise, manipulation and detection of circular polarization of electromagnetic waves is important in modern technology. artificially generating circular polarization is significantly more challenging in microwave communication technology. for instance, circular polarization is widely used in microwave communication and satellite communication systems. in addition, the cp achieves reflection effect, atmospheric absorption and lower susceptibility and intrinsically lower cross polarization discrimination. 1 department of physics, shah abdul latif university khairpur, sindh, pakistan 2 institute of chemistry, shah abdul latif university khairpur, sindh, pakistan corresponding email: farman.mangi@salu.edu.pk an electronically steerable cp antenna array is more efficient for the inter-aircraft communication in terms of mobile nodes and wireless communication. the common application of antenna arrays is complex due to reduced level of practically-achievable output for extended millimetre wave communication network [1]. the cp antenna array approach was introduced for the use of a linearly polarised antenna array and electromagnetically coupled polarising wave plate. dielectric polarisers [2], meander-line [3-5] and grid-plate [6] polarisers have been proposed to convert linear polarised electromagnetic waves to circular. cp antenna array is the combination of individual antenna elements which realize the directivity requirement and gain for the long distance [7mailto:farman.mangi@salu.edu.pk farman ali mangi (et al.), low loss transmission circular polarizer for ku band application (pp. 28 33) sukkur iba journal of emerging technologies sjet | volume 1 no. 1 january – june 2018 © sukkur iba university 28 8]. in previous research contribution, the transmission type circular polarizers were proposed, such as u-shape split ring resonators, metallic helices, parallel plates, twisted q-shaped metasurface, split ring resonator [9-10]. the four patch antennas were selected to produce 90o phase shift and [11] introduces an elliptical cp dielectric resonator antenna array. in [12, 13], the thin dual-band polarizer was designed for satellite applications and meta-device with different functionalities is integrated. the several known cp antennas composed of different multi-pot feed networks and radiation elements which makes them inefficient for practical application. the end fire antenna array are introduced to date [14, 15] which are constructed of seamless integration with linearly polarized. polarization state of electromagnetic waves affect our daily life in order to consumer products to high technology applications [16]. the characteristics of a non-isotropic transparent material based on the electromagnetic waves incident upon a birefringent material. if e field converted in two orthogonal components of ex and ey having same amplitude, the phase shift of any one component will result in circular polarization and satisfy the phase shift 90o is known as quarter wave plate. the intensity of the incident electromagnetic wave does not change after propagating through a wave plate (only the polarisation state is changed). wave plates are mostly considered as linearly birefringent, which means that the index of refraction differs along the two principal axes, which affects the phase shift of the orthogonal components differently [17]. quarter wave plate possesses intriguing property to convert linear-to-circularly polarized waves when it is twisted at 45o to the impinging polarizing plane. the unique characteristics of quarter wave plate is to change em waves from linear-to-circularly polarized states. most often, the manipulation or polarization control can be obtained with quarter wave plate [18]-[24]. the phase difference between outcome two orthogonal transmitted waves is quarter of the wavelength 90o when impinged wave is linearly polarized at 450 and quarter wave plate has ability to change the impinged wave to circular polarization [25]. frequency selective surface (fsss) are developed as special filter and polarization transformer for microwave and millimetre waves. they are considered for many applications such as telecommunication, dichroic reflectors, waveguides and wireless security. [26-28]. fsss can also be considered as polarizer [29-31] which has overall good performance and ease fabrication. the structure based on 15 x15 arrays of dual split ring resonators to demonstrate the transmission phase [32]. 2. structure of single layer polarizer first of all we have proposed single strip polarizer that operate at 13.20 ghz is designed and fabricated to produce perfect right hand circular polarization. this single strip acts as a quarter-wave plate that transforms a linearly polarized incident wave into a circularly polarized transmitted wave. a single strip oriented at 45° with λ/4 arm length along the x-y plane in simple unit cell. whereas, the lengths of the single strip in x-y directions is 7.5 mm and width is 2 mm. perfect electric conductor (pec) material is used to the strip. the periodicity positions of the unit cell in three axes are x=28, y=, 28 and z= 25.25, respectively. farman ali mangi (et al.), low loss transmission circular polarizer for ku band application (pp. 28 33) sukkur iba journal of emerging technologies sjet | volume 1 no. 1 january – june 2018 © sukkur iba university 29 fig. 1. view of circular polarizer based on single strip. 3. structure of circular polarizer circular polarizer using fss design for 15.25 ghz and 15.28 ghz applications. using this fss to obtain cp at resonant frequencies. in this structure, two metallic strips are placed perpendicular at angle +45o and -45o along x-y directions and separated at the distance of 7.2 mm perpendicularly from each other. the fss polarizer is depicted in fig.2. the proposed structure is constructed as cross dipole with λ/4 arm length along x-y axis. the length of each strips are selected 7.5 mm and 2mm wide, respectively. the perfect electric conductor (pec) material is used to strips. the periodicity positions of the unit cell in three axes are x=33, y=, 33 and z= 54, respectively. fig. 2. view of circular polarizer based on two metallic strips. 4. simulation analysis for simulation purpose, the hfss software is used in terms of periodic boundary conditions. the impinged wave through floquet port one converted into circular polarized waves. the incident em wave slanted at 45o and emerge in to two decomposed orthogonal waves ex and ey to realize pure cp as shown in fig.1. it can be observed that the transmission loss of designed structure -3.2 db at the 13.2 ghz as depicted in fig. 4. the axial ratio is 1.1 corresponds to phase difference of 90o at resonant frequency of 13.2 ghz mentioned in fig.3 & 5. the rhcp wave and lhcp wave are generated at distinct resonant frequencies. the transmission loss of dual polarizer at the rhc polarization is -1.8 db and at lhc polarization is -2.6 db with respect to resonant frequencies 15.25 ghz and 15.28 ghz. meanwhile, corresponding phase differences between outcome waves ex and ey are depicted in fig. 5 and 8. the simulated phase differences of outcome waves are satisfied at 90o to achieve pure cp at resonant frequencies. fig. 3. axial ratio at 13.20 ghz. 5. theoretical results the hfss software is used to analyze the obtained phase difference and magnitudes of output orthogonal components through designed low loss transmission circular polarizer. while, phase difference and transmission magnitudes of outcome waves farman ali mangi (et al.), low loss transmission circular polarizer for ku band application (pp. 28 33) sukkur iba journal of emerging technologies sjet | volume 1 no. 1 january – june 2018 © sukkur iba university 30 can be directly calculated by formula ex/ey and δϕ = exϕ – eyϕ. in fig.1, the unit cell structure is depicted in fig.1 which is oriented at 45o in x-y direction. the transmitted of two orthogonal waves is same at 13.20 ghz which converts linear-to-circularly polarized wave. the calculated axial ratio of outcome two waves is 1.1 at 13.20 ghz depicted in fig. 3. the low loss transmission of the generated waves is noticed due to reflection of polarized constructed by single metallic strip. the generated orthogonal waves are same at 13.20 ghz but transmission loss about -3.2 db is observed. obviously, the calculated transmission loss impact on the transmission power through single layer structure. the calculated phase difference of cp is 90o at the 13.20 ghz which corresponds to axial ratio between two outcome waves as mentioned in fig. 3. fig. 4. transmission magnitudes at 13.20 ghz. fig. 5. phase difference at 13.20 ghz. the transmission loss of single-layer polarizer oriented at 450 in x-y direction is 3.2 db as shown in fig. 4. furthermore, a innovative technique has been proposed to reduce transmission loss of single polarizer based on introducing the dual layer polarizer mounted perpendicularly to each other in the x-y direction as shown in fig. 2. the magnitudes of output orthogonal components are similar at the frequency of 15.25 ghz and 15.28 ghz to obtain the rhcp and lhcp. nevertheless, it is necessary to obtain the circular polarization the phase difference of two orthogonal components ex and ey of e field must be satisfied at 90 0 .the transmission axial ratio between two orthogonal components is 1.4 and 1.2 at 15.25 ghz and 15.28 ghz as shown in fig. 6. whereas, the phase difference between two orthogonal components ex and ey is calculated by the phase difference formula of circular polarization. the transmission loss after reflection from the polarizer surface as shown in fig.7 indicates the transmission magnitude of e components ex and ey in db are -1.8 at 15.25 ghz and -2.60 at 15.28 ghz as shown in fig. 7. it means that the magnitude of both orthogonals ex and ey components are same. the transmission loss is observed -1.8 and 2.6 db that effect the transmission of waves through polarizer. it is observed that the transmission loss of dual layer polarizer has been reduced against single polarizer as shown in fig. 7. the circular polarization can be calculated by the following expression. ∆∅ = ∅𝐲 − ∅𝐱 = { + ( 𝟏 𝟐 + 𝟐𝐧 ) 𝛑, 𝐧 = 𝟎, 𝟏, 𝟐, … … … … +(( 𝟏 𝟐 + 𝟐𝐧 ) 𝛑, 𝐧 = 𝟎, 𝟏, 𝟐, … … … … (𝟏) it is observed circular polarization achieved when axial ratio value of two orthogonal components is satisfied 1.2 at certain mentioned frequencies and correspond to 89.90 phase difference of two components. 10.00 11.00 12.00 13.00 14.00 15.00 16.00 freq [ghz] -12.00 -10.00 -8.00 -6.00 -4.00 -2.00 0.00 t r a n s m is s io n ( d b ) m1 name x y m1 13.2000 -3.2427 10.00 11.00 12.00 13.00 14.00 15.00 16.00 freq [ghz] -375.00 -250.00 -125.00 0.00 125.00 250.00 375.00 p h a s e d i f f e r e n c e [ d e g ] m1 name x y m1 13.2000 90.5632 farman ali mangi (et al.), low loss transmission circular polarizer for ku band application (pp. 28 33) sukkur iba journal of emerging technologies sjet | volume 1 no. 1 january – june 2018 © sukkur iba university 31 therefore, we have achieved at about 99% rcp and lcp at the frequencies of 15.25 ghz and 15.28 ghz as shown in fig.6 and 7. the phase difference is calculated by deducing the value form fig. 8 and verified by above equation 1. fig. 6. axial ratio is at 15.25 ghz and 15.28 ghz. fig. 7. transmission magnitude at 15.25 ghz and 15.28 ghz. fig. 8. phase difference at 15.25 ghz and 15.28 ghz. 6. conclusion in conclusion, we proposed the low loss transmission circular polarizer using two metallic strips to investigate the transmission characteristics with pure circular polarization at 15.25 ghz and 15.28 ghz. the designed structure is based on fss which generates the thcp wave and lhcp wave at resonance frequencies. the constructed model is simple and could be designed and fabricated easily by using hfss software with high precision. the reflection and transmission characteristics are good features of the designed structure. in addition, the design techniques can be employed to construct the polarizers using double layer polarizers based on metallic strips or split ring resonators for millimetre, micrometre and terahertz frequencies. in future, this research can be carried out to compose polarizers using fsss to extend the bandwidth and reduce the transmission loss. references [1] v. dyadyuk and y. j. guo, “towards multi-gigabit ad-hoc wireless networks in the e-band”, ieee global symposium on millimeter waves, sendai, japan, 2009. [2] l. goldstone, “mm wave transmission polariser,” in antennas and propagation society international symposium, 1979, vol. 17, pp. 606–609. [3] l.young, l. robinson, and c. hacking, “meander-line polarizer,” ieee transactions on antenna and propagation, vol. 21, pp. 376-378, 1973. [4] r. s. chu and k. m. lee, “analytical method of a multilayered meander-line polarizer plate with normal and oblique plane-wave incidence,” ieee transactions on antenna and propagation, vol. 35, pp. 652-661, 1987. [5] m. mazur and w. zieniutycz, “multilayer meander line polarizer for ku band,” 13th international conference on 10.00 11.00 12.00 13.00 14.00 15.00 16.00 freq [ghz] 0.00 250.00 500.00 750.00 1000.00 1250.00 1500.00 1750.00 m a g ( a x ia l_ r a ti o ) m1m2 name x y m1 15.2500 1.4416 m2 15.2800 1.2433 10.00 11.00 12.00 13.00 14.00 15.00 16.00 freq [ghz] -35.00 -30.00 -25.00 -20.00 -15.00 -10.00 -5.00 0.00 5.00 t r a n s m is s io n ( d b ) m1 m2 name x y m1 15.2800 -2.6009 m2 15.2500 -1.8272 10.00 11.00 12.00 13.00 14.00 15.00 16.00 freq [ghz] -300.00 -200.00 -100.00 0.00 100.00 200.00 300.00 400.00 p h a s e a n g le [ d e g ] m2 m3 name x y m2 15.2500 91.1230 m3 15.2800 -89.9264 farman ali mangi (et al.), low loss transmission circular polarizer for ku band application (pp. 28 33) sukkur iba journal of emerging technologies sjet | volume 1 no. 1 january – june 2018 © sukkur iba university 32 microwaves, radar and wireless communication, vol. 1, pp. 78-81, 2000. [6] z. chen , x. li, “novel mixed grid-plate circular polarizers,” 4th international conference on microwave and millimeter wave technology (icmmt 2004), proc. pp. 66 – 69, aug. 2004. [7] w. zhou, n. h. noordin, n. haridas, a. o. el-rayis, a. t. erdogan and t. arslan, “a wifi/4g compact feeding network for an 8-element circular antenna array,” loughborough antennas and propagation conference (lapc2011), pp. 1-4, 14-15 nov. 2011. [8] m. k. a. rahim, t. masri, o. ayop and h. a. majid, “circular polarization array antenna,” asia-pacific microwave conference, apmc 2008, pp. 1-4. [9] m. fartookzadeh and s. h. mohseni armaki, “enhancement of dual-band reflection-mode circular polarizers using dual-layer rectangular frequency selective surfaces,” ieee transactions on antennas and propagation, vol. 64, no. 10, 2016. [10] h. cao, j. liang , x. wu and et al, “dualband polarization conversion based on non-twisted q-shaped metasurface,” optics communications, vol. 370, 2016. [11] s. l. s. yang, r. chair, a. a. kishk, k.f. lee and k.-m. luk, “study on sequential feeding networks for subarrays of circularly polarized elliptical dielectric resonator antenna,” ieee transactions on antennas and propagation, vol. 55, pp. 321-333, 2007. [12] n. j. g. fonseca and cyril mangenot, “high-performance electrically thin dual-band polarizing reflective surface for broadband satellite applications,” ieee transactions on antennas and propagation, vol. 64, no. 2, 2016. [13] h. x. xu, s. sun, s. tang and et al., “dynamical control on helicity of electromagnetic waves by tunable metasurfaces,” sci. rep, vol. 6, 2016. [14] h. uchimura, n. shino, k. miyazato, “novel circular polarized antenna array substrates for 60ghz-band,” ieee mtts international microwave symposium digest, 12-17 june 2005 page(s):4. [15] s. w. wang et al., “a circular polarizer designed with a dielectric septum loading,” ieee transactions on microwave theory and techniques, vol. 52, no. 7, pp. 1719-1723, 2004. [16] n. k. grady et al., “terahertz meta material for linear polarization conversion and anomalous refraction,” science vol. 340, no. 14 june 2013, pp. 1304, [17] g. i. kiani, and v. dyadyuk, “quarterwave plate polarizer based on frequency selective surface,” european microwave conference, pp. 1361–1364, 28-30 sept. 2010. [18] d. lerner, “a wave polarization converter for circular polarization,” ieee trans. antennas propag., vol. ap13, no. 1, pp. 3–7, jan. 1965. [19] l. young, l. robinson, and c. hacking, “meander-line polarizer,” ieee trans. antennas propag., vol. ap-21, no. 3, pp. 376–378, mar. 1973. [20] r.-s. chu and k.-m. lee, “analytical method of a multilayered meander-line polarizer plate with normal and obliqueplane-wave incidence,” ieee trans. antennas propag., vol. ap-35, no.6, pp. 652–661, jun. 1987. [21] a. k. bhattacharyya and t. j. chwalek, “analysis of multilayered meander line polarizer,” int. j. microw. millimeterwave comput.-aided eng., vol. 7, no. 6, pp. 442–454, 1997. [22] m. euler, v. fusco, r. cahill, and r. dickie, “comparison of frequencyselective screenbased linear to circular split-ring polarisation convertors,” iet microw., antennas, propag., vol. 4, no. 11, pp. 1764–1772, 2010. farman ali mangi (et al.), low loss transmission circular polarizer for ku band application (pp. 28 33) sukkur iba journal of emerging technologies sjet | volume 1 no. 1 january – june 2018 © sukkur iba university 33 [23] m. euler, v. fusco, r. cahill, and r. dickie, “325 ghz single layer submillimeter wave fss based split slot ring linear to circular polarization convertor,” ieee trans. antennas propag., vol. 58, no. 7, pp. 2457–2459, jul. 2010. [24] m. joyal and j. laurin, “analysis and design of thin circular polarizers based on meander lines,” ieee trans. antennas propag., vol. 60, no. 6, pp. 3007–3011, jun. 2012 [25] c. pfeiffer and a. grbic, “millimeterwave transmitarrays for wavefront and polarization control,” ieee transactions on microwave theory and techniques, vol. 61, no. 12, pp, 4407, december 2013, [26] b. a. munk, frequency selective surfaces, theory and design, john wiley & sons inc, 2000. [27] g. i. kiani, a. r. weily, and k. p. esselle, “a novel absorb/transmit fss for secure indoor wireless networks with reduced multipath fading,” ieee microwave and wireless components letters, 16, pp. 378-380, 2006. [28] g. i. kiani, k. l. ford, k. p. esselle, a. r. weily, and c. j. panagamuwa, “oblique incidence performance of a novel frequency selective surface absorber,” ieee transactions on antennas and propagation, vol. 55, pp. 2931-2934, 2007. [29] a. strikewerda et al., “comparison of birefringent metamaterials and meaderline structure as quarter-wave plates at terahertz frequencies,” optics express, 17, pp. 136-149, 2009. [30] k. karkkainen, and m. stuchly, “frequency selective surface as a polarisation transformer,” iee proceedings on microwaves, antennas and propagation, vol. 149, pp. 248-252, 2002. [31] s. a. winkler, w. hong, m. bozzi, and k. wu, “a novel polarization rotating frequency selective surface based on substrate integrated waveguide technology,” in proceedings of the 39th european microwave conference, rome, italy, 2009. [32] h. x. xu, s. tang, g. m. wang and et al., “multifunctional microstrip array combining a linear polarizer and focusing metasurface,” ieee transactions on antennas and propagation, vol. 64, no. 8, (2016). format template vol. 6, no. 1 | january – june 2023 sjet | p-issn: 2616-7069 |e-issn: 2617-3115 | vol. 6 no. 1 january – june 2023 35 food recognition system: a new approach based on wavelet-lstm ghulam hussain1, ali raza radhan2, irfan ali tunio1 , mohsin shaikh2, umair saeed solangi1, kamran javed3* abstract: an automated system for analyzing daily dietary intake is essential for human well-being and healthcare. this work presents a novel wearable necklace embedded with a piezoelectric sensor and a microcontroller to monitor food ingestion of users. to effectively represent the food ingestion patterns, the sensor signal is dynamically segmented using a bidirectional search technique. each segmented food intake pattern consists of a chewing sequence and a swallow peak. we exploit wavelet transform to decompose the complex food ingestion patterns, collected by the sensor, into frequency sub-bands at discrete scales. the frequency sub-bands are used as sequences to train long short-term memory (lstm) for the recognition of 5 food categories. our proposed recognition model based on wavelet-lstm recognizes 5 food classes with an accuracy of 98.1%. .keywords: food recognition, signal segmentation, wearable sensors, signal processing introduction obesity is the most common disease present in every third human being. it is defined as excessive fat deposition in a person’s body, which is caused by the imbalance between energy intake and energy expenditure. people consuming high caloric food in large quantity suffer from obesity. the previous researches reported obesity as a source of other diseases, such as hepatitis, diabetes, cardiovascular and cancer [1]. a comprehensive review was previously performed to investigate the performance and usability of different food dietary monitoring systems, which encorporated various sensors and applied numerous sophasticated signal processing techniques to determine eating behvior, classify food type, and estimate amount of food [2]. there were mainly two approaches discussed such as manual and automatic. manual approaches are proven to biased and innacurate due to relying on subjective reports and recall. there is a need for an automated system to monitor the daily dietary intake of obese subjects. moreover, the system should be non-invasive so that people can use it easily during routine tasks to regulate their energy intake. improvement in the field of artificial neural networks provides an opportunity for 1dept. electronic engineering, quaid-e-awam university, larkana, pakistan 2dept. computer science, quaid-e-awam university, larkana, pakistan 3national centre of artificial intelligence (ncai), saudi data and artificial intelligence authority (sdaia), riyadh, saudi arabia; corresponding author: kamran@skku.edu, engr.ghulam.hussain@quest.edu.pk mailto:kamran@skku.edu mailto:engr.ghulam.hussain@quest.edu.pk ghulam hussain (et al.), food recognition system: a new approach based on wavelet-lstm (pp. 35 43) sukkur iba journal of emerging technologies sjet | vol. 6 no. 1 january – june 2023 36 researchers to design an intelligent and noninvasive food intake system that can assist individuals to monitor their daily food intake without requiring a lot of effort. there are many studies to monitor the daily food intake using various sensors, such as a microphone, piezoelectric, accelerometer, gyroscope, camera, and strain gauge. the piezoelectric and microphone-based systems have attained higher recognition performance than the rest [3]. the authors in [3] attained an accuracy of 80.3% through the training of a conventional machine learning algorithm on manually extracted features. the manually extracted statistical features in different domains can improve food recognition as it is also validated in [4]. on the contrary to [3], alshurafa et al. [4] improved the recognition by employing the handcrafted features in timeand frequency-domain (tfd), obtained using short-time fourier transform. they have improved the food recognition performance, but their system lacks dynamic segmentation technique and efficient features extraction algorithm, which are essential for any recognition task. the segmentation of the wearable sensor signals into essential parts assist in accurate analysis of events of interest. here, the events are related to ingestion activity such as chewing and swallow. segmentation of signal actually helps in separate out the ingestion activity related data from silent phases [5]. we were inspired by the previous methodology of signal segmentation [5], in which signals collected by the wearable devices [6-7] were segmented using detection and selection techniques. the important activity was detected first by applying some threshold maxima [5,8-9]. later, the beginning and ending of the detected activity is determined in selection stage [5]. unlike deterministic segmentation approaches, probabilistic bayesian approach is also reported in literature for estimating the segments of signals [10]. recently, a new approach based on deep learning (dl) algorithm automatically extracts the features in tfd to perform the recognition of the ecg signals [5]. however, their approach uses traditional static segmentation (ss) to segment the signals. the ss cannot completely cover the events in the naturally occurring body-signals. the drawbacks of manual and static segmentation (ss) approaches [3–5] motivated us to design a novel bidirectional search (bs) algorithm that can segment the ingestion patterns (ips) both automatically and dynamically. in this study, a piezoelectric sensor is employed and preferred over the microphone as the performance of microphone-based systems degrades owing to surrounding noise [4]. the contributions of the proposed study can be best described in three folds: 1) the novel wearable system is designed to collect ingestion patterns of different food categories, 2) an efficient signal segmentation approach known as bidirectional search algorithm is developed to dynamically segment ingestion events of varying size such as chewing and swallow, 3) sophisticated wavelet-transform based lstm model has outperformed current state-of-the-art studies by recognizing five food classes with an accuracy of 98.1%. our proposal: the proposed food recognition system, shown in figure 1, consists of a piezoelectric sensor, lilypad microcontroller, and smartphone application. the sensor and the microcontroller are integrated into a stretchable necklace, which is worn around the neck by the subjects. the smartphone application communicates with the necklace via bluetooth for data logging, and then it transfers the data to a cloud server for further data analytics. moreover, the smartphone application provides an interface to users for interaction with the food intake system. the sensor in the necklace generates distinct ips for different food categories, as shown in figure 2. each intake pattern consists of chewing sequence and a swallow. owing to different characteristics of food, chewing period while ingestion of each food varies. therefore, dynamic segmentation is required ghulam hussain (et al.), food recognition system: a new approach based on wavelet-lstm (pp. 35 43) sukkur iba journal of emerging technologies sjet | vol. 6 no. 1 january – june 2023 37 to effectively represent the sensor data. the bs technique processes the input data and separates the ips from unwanted data. in the proposed study, the word unwanted data refers to the data that is not related to the ingestion activity. bs technique, illustrated in algorithm 1, performs two searches: first for swallow event in the forward direction; and second for supportive events or chewing sequence associated to the swallow event found during the first search. during the first search, the swallow event is spotted based on the change in the amplitude ∆aqi of neighboring samples. aqi and aqr denote ith swallow event and related chewing sequence, respectively. then, the related chewing sequence is searched in the backward direction. the start of chewing sequence is decided based on the change in the amplitude aqr of the samples. swallow event and chewing sequence are determined by comparing the values of change in amplitudes (aqi;aqr) to the thresholds (θ1; θ2) as illustrated in the algorithm. swallow event found in the forward search marks end of the ip. the chewing sequence found during backward search denotes the start of the ip. thus, the bs technique helps to split the input data into the dynamic segments (dss) automatically, shown in figure 2(b). a fixed window length was chosen previously for the segmentation [3–14], but their accuracy degraded for the ingestion sequences of varying length as the duration of the ips depends on the bite size and food type a person ingests. therefore, the dss are well suited to represent the ips. the dimension of the dss is (a) (b) figure 1: the proposed food recognition system (a) wearable embedded module (b) deep learning based food recognition model fig 1: proposed food recognition system ghulam hussain (et al.), food recognition system: a new approach based on wavelet-lstm (pp. 35 43) sukkur iba journal of emerging technologies sjet | vol. 6 no. 1 january – june 2023 38 reduced further by the wavelet transform that forms the efficient sequences to be trained on the classifier. the computational complexity of the bs is o(n m). n is length of each ingestion pattern and m is number of ingestion patterns. wavelet transform: wavelet transform decomposes the segments, containing complex food ips, into frequency sub-bands at various discrete scales. wavelet transform, unlike the fourier transform, accurately analyses the data containing abrupt changes (swallows), by localizing spectral content of the signal in time. we employ a discrete wavelet transform (dwt) to characterize the oscillatory behavior of the ip segment. the ip signal consists of slow trends and abrupt changes as it carries the complex events of chewing and swallow together. hence, there is a need for complex wavelet or basis function that can efficiently represent the complex ip. we implemented dwt using the filter-banks method. different combinations of wavelets and levels of decomposition were tested using long short-term memory (lstm). lstm network was designed to overcome the vanishing gradient problem that can occur in traditional recurrent neural networks, allowing them to better handle long-term dependencies in sequential data [15]. recently, lstm has emerged as the most widely applied model in analysis of sequential healthcare data [11]. daubechi algorithm 1 bidirectional search (bs) algorithm 1: input: ϒ : input data, ҡ=1 : search limit, 𝝓𝒊 : segment index 2: for t ← 1, 𝒕𝒎𝒂𝒙 do 3: if (y ← forwardsearch (ϒ[t : t+5])) is true then 4: δ ← t + 5 5: ʋ ← backwardsearch (ϒ[ҡ : δ]) 6: 𝝓𝒊 ← ϒ[ʋ : δ] 7: t ← ҡ = δ + 1 ► ҡ: new search limit 8: else 9: search again go to line2 10: end if 11: end for 12: function forwardsearch (y[ⅈ : ⅈ + 5]) 13: if (▲ 𝑨𝒒𝒊 = μ (y [q= ⅈ + 1 : ⅈ + 5]) – y [ⅈ]) < 𝜽𝟏 then 14: return y as true 15: else 16: return y as false 17: end if 18: end function 19: function backwardsearch(y[ϒ : ⅈ]) 20: for r ← ⅈ, ϒ do 21: if (▲ 𝑨𝒒𝒓 = μ (y [q= r 1 : ⅈ 5]) – y [r]) < 𝜽𝟐 then 22: return ʋ ← r – 5 23: else 24: search again go to line20 25: end if 26: end for 27: end function ghulam hussain (et al.), food recognition system: a new approach based on wavelet-lstm (pp. 35 43) sukkur iba journal of emerging technologies sjet | vol. 6 no. 1 january – june 2023 39 wavelet with 4 levels of decomposition is selected as the best combination based on the recognition performance of the lstm model. therefore, we have chosen daubechies wavelet as a mother wavelet (ψ𝑠,𝜏 (𝑡)) given in equation (1) to analyze the complex ip. ψ𝑠,𝜏 (𝑡) = 1 √𝑠 ψ ( 𝑡 − 𝜏 𝑠 ) (1) the chosen wavelet is scaled (s) and shifted (𝜏) along the entire length (t) of the segment to be multiplied later. the coefficient ( 1 √𝑠 ) normalizes energy of the wavelet. for the dwt representation, the s and 𝜏 parameters are replaced with values of 2−𝑗 and k. 2−𝑗, respectively. the j and k denote the scale and the shift parameters in the dwt. to define the wavelet basis (ψ𝑗,𝑘 (𝑡)), the equation (1) is updated by substituting the parameters and given as. ψ𝑗,𝑘 (𝑡) = 2 1 2 ψ(2𝑗 𝑡 − 𝑘) (2) dwt analyze the input signal or segment (𝜙𝑖 ) by multiplying it with a wavelet function (ψ), which results in values of the coefficients 𝑐𝑖 (j, k) as shown in equation (3). the process is repeated for all segments to represent each 𝜙𝑖 with fewer coefficients 𝑐𝑖 (j, k). the main aim of applying dwt on the segments is to represent the signal pattern with the efficient sequences, the coefficients, without acquiring redundancy. food recognition using wavelet-lstm: the coefficients, computed through the dwt, form efficient and accurate sequences for each 𝑐𝑖 (𝑗, 𝑘) = ∑ 𝜙𝑖 𝑡 (𝑡) ψ𝑗,𝑘 (𝑡) (3) segment containing the ips. the sequences for the ips are fed into the lstm. the lstm contains input (𝜓𝑡 ), forget (𝑓𝑡 ), output (𝑜𝑡 ), and input modulating (𝜗𝑡 ) gates along with a memory cell (𝑐𝑡 ) and a hidden state (ℎ𝑡 ). the gates regulate the input information (sequences) so that it can be written to, read from, or stored in the memory during each time step as given in equation (4). the lstm, unlike other dl models, reduces the overall (a) (b) figure 2: wearable sensor signal (a) ingestion patterns (ips) signal, (b) ips segmentation fig. 2; (a) ingestion patterns (ips) signal, (b) ips segmentation ghulam hussain (et al.), food recognition system: a new approach based on wavelet-lstm (pp. 35 43) sukkur iba journal of emerging technologies sjet | vol. 6 no. 1 january – june 2023 40 number of parameters by sharing the same weights across all the time steps. the lstm trains on the input sequences by using the forward and backward processes temporally. the forward and backward processes assist the network to tune the parameters or weights table 1: the comparison of the previous studies and the proposed study study segmentation features (domain) accuracy [3] static handcrafted features (time) 80.3% [4] static handcrafted features (tfd) 90.0% [11] static algorithm extracted features (tfd) 97.4% proposed dynamic algorithm extracted features (tfd) 98.1% (w, r, b, p) using an optimization algorithm for minimizing the recognition error during training on the input sequences (𝑥𝑡 ) [4]. 𝜗𝑡 = tanh (𝑊 𝜗 𝑥𝑡 + 𝑅 𝜗 ℎ𝑡−1 + 𝑏𝜗): input modulating gate (4a) figure 3: food recognition using proposed system based on wavelet lstm ghulam hussain (et al.), food recognition system: a new approach based on wavelet-lstm (pp. 35 43) sukkur iba journal of emerging technologies sjet | vol. 6 no. 1 january – june 2023 41 𝜓𝑡 = sigm(𝑊 𝜓 𝑥𝑡 + 𝑅 𝜓 ℎ𝑡−1+ 𝑃 𝜓 ʘ 𝜃𝑡−1 + 𝑏𝜓 ): input gate (4b) 𝑓𝑡 = sigm (𝑊 𝑓 𝑥𝑡 + 𝑅 𝑓 ℎ𝑡−1 + 𝑝 𝑓 ʘ 𝜃𝑡−1 + 𝑏𝑓 ): forget gate (4c) 𝑜𝑡 = 𝑠𝑖𝑔𝑚(𝑊 𝑜 𝑥𝑡 + 𝑅 𝑜 ℎ𝑡−1 + 𝑝 𝑜 ʘ 𝜃𝑡 + 𝑏𝑜 ): output gate (4d) ℎ𝑡 = tanh (𝜃𝑡 ʘ 𝑜𝑡 ): hidden state or block output (4e) 𝜃𝑡 = 𝜗𝑡 ʘ 𝜓𝑡 + 𝜃𝑡−1 ʘ 𝑓𝑡 : cell state (4f) the lstm network, a dl architecture, offers an end-to-end learning strategy, in which features extraction and classification are performed together automatically. contrary to the conventional handcrafted features techniques, the dl model extracts the important and efficient features that enable the classifier to accurately predict the food class of the input sequences. we 4 bands discrete wavelet decomposition to generate components of detailed d1, d2, d3, d4 and approximate a4. these five detailed (d, d2, d3, d4) and approximate (a4) components are used as features for lstm model. the data in the form of the sequences, carrying the tempo spectral contents of ips, are split into two sets: training (75%) and test (25%). a set of optimal hyperparameters is selected prior to training, as these parameters have a significant impact on the performance of the lstm. then, the lstm model is trained on the training data, containing the ips of 5 foods, to associate the wavelet sequences with the correct food class label. to assess the recognition-ability, the trained lstm is evaluated on the test data (i.e., unseen sequences). the proposed model recognizes the test sequences of 5 food classes with an accuracy of 98.1% as shown in figure 3. results and discussion: a total of 15 subjects (10 males and 5 females, average age 31.4 12.9− + years, average body mass index (bmi) 27.1 6.09− + kg/m2) participated in the experiment. all subjects signed a consent form prior to the experiment and their information is protected following the declaration of helsinki. there are five food categories, (such as chips, peanuts, pizza, apple and water), chosen for recording ingestive behavior of the participants. each subject took part in the experiment three times and ate food items from each of the categories. the subjects wore necklaces while they ingested the food items. the wearable sensor generates distinct ips for each food category due to different characteristics such as hardness, stickiness, and crunchiness. these characteristics of foods alleviate the need for the complex classifier to recognize the ips. furthermore, the different characteristics present in each food category cause the different duration of the ips, which cannot be covered with the conventional ss. for monitoring the ips application, the ss approach is not suitable as the duration of the patterns varies depending on the bite size and food type. electroglottograph (egg) based system was designed to automatically monitor diet and food intake. they achieved reasonably accuracy for predicting eating episodes using static signal segmentation technique [16]. a multi-senor fusion based system was developed to classify collected activity data between eating and non-eating activities [17]. camera based objection detection method was used to determine normal eating and stressed eating [18]. the performance of method can be degraded if objects are not aligned to line-ofsight of camera. a wearable diet monitoring system was presented to classify liquid and solid food categories [19]. the system detected normal breathing and swallow containing breathing cycles, which were further associated to liquid and solid intakes. the proposed may falsely consider interfering activities, coughing and talking, as swallow breathing cycle that can reduce the recognition performance. an integrated wearable necklace was applied to collect ingestion patterns which were passed through lstm network to detect and count the swallows [20]. the method was mainly focused on eating disorder and did not address the problem of food classification. these methods did not attain high accuracy in food classification due to traditional static signal segmentation. comparing to the static signal segmentation approaches, the dynamic segmentation improves the representation of the data [5]. we have employed the bs to segment the ips correctly around the two main events: chewing ghulam hussain (et al.), food recognition system: a new approach based on wavelet-lstm (pp. 35 43) sukkur iba journal of emerging technologies sjet | vol. 6 no. 1 january – june 2023 42 and swallow. moreover, we transformed the dss into the wavelet sequences (i.e., data in tfd) using dwt, which are fed into the lstm model. dwt converts the ingestion pattern containing dss into the well-organized sequences. the food recognition model based on the lstm as shown in figure 1(b) is trained and evaluated using 15-fold cross-validation technique with leave-one-subject-out. we used leave-one-subject-out validation technique for enabling the model to gain generalization ability to recognize food categories based on ingestion data of participants. the model trained on data of fourteen subjects and leftone-subject-out for validation. the advantage of the leave-one-subject-out strategy is that it provides a rigorous evaluation of the model's performance on the data from previously unseen subjects or users. before training the recognition model, the optimal hyperparameters for the lstm were selected through evaluating the model's performance with various combinations of parameters. the hyperparameters are computational components that can significantly impact the solution achieved by the learning algorithm [21]. the optimal set of hyperparameters was chosen. a stochastic gradient descent with momentum was used as the optimization algorithm since it is consistently faster than other gradient descent methods. the added momentum improved the convergence rate. the optimization algorithm helped the model minimize the loss function by iteratively optimizing the parameters. the initial learning rate was set to 0.01, and it started decreasing every 30 iterations using piece-wise learning rate scheduling [22]. a minimum batch size of 30 was set for each training iteration, and the training was limited to a maximum of 40 epochs. batch normalization was conducted before training to avoid an internal covariate shift problem, which is a change in the network parameters transforming the distribution of the network. the number of training and test instances are 5850 and 1950, respectively. the lstm automatically extracts the efficient features and accurately recognizes the ips of 5 food classes. our proposed food recognition model attains 98.1% accuracy and outperforms as compared to previous studies as detailed in table. our proposed approach achieves 18% and 7% higher accuracy, as compared to static segmentation handcrafted features approach [3] and [4], respectively. conclusion and future work: in this paper, we presented a new food recognition system based on wavelet-lstm for recognizing the ingestion patterns of 5 food classes. dwt converts the dynamic segments into the sequences, which are fed into the lstm model. we emphasized dynamic segmentation as it is essential to cover the chewing and swallow events of varying durations. the lstm attains high recognition performance for 5 food classes by automatically extracting the efficient features from the wavelet sequences. the proposed system attains stateof-theart performance by recognizing the 5 food classes with 98.1% accuracy. our future work aims to expand the number of food classes and incorporate interfering activities such as coughing and talking to develop a more robust food recognition system. this will offer obese individuals more options to monitor their dietary intake effectively. references: [1] shaikh, mohsin, et al. "open-source electronic health record systems: a systematic review of most recent advances." health informatics journal 28.2 (2022): 14604582221099828. [2] vu, tri, et al. "wearable food intake monitoring technologies: a comprehensive review." computers 6.1 (2017): 4. [3] hussain, g., et al. ‘food intake detection and classification using a necklace-type piezoelectric wearable sensor system,’ ieice trans. on inform. and syst., 2018, 101, (11), pp. 2795–2807. [4] alshurafa, n., et al. ‘recognition of nutrition intake using time-frequency decomposition in a wearable necklace using a piezoelectric sensor,’ ieee sensors journal, 2015, 15, (7), pp. 3909–3916. [5] alonso-arévalo ma, cruz-gutiérrez a, ibarra-hernández rf, garcía-canseco e, ghulam hussain (et al.), food recognition system: a new approach based on wavelet-lstm (pp. 35 43) sukkur iba journal of emerging technologies sjet | vol. 6 no. 1 january – june 2023 43 conte-galván r. robust heart sound segmentation based on spectral change detection and genetic algorithms. biomedical signal processing and control. 2021 jan 1;63:102208. [6] hussain g, javed k, cho j, yi j. food intake detection and classification using a necklace-type piezoelectric wearable sensor system. ieice transactions on information and systems. 2018 nov 1;101(11):2795-807. [7] cho hj, hussain g, park jh, kim jh, cho jd. visual fatigue measurement model based on multi-area variance in a stereoscopy. in2016 18th international conference on advanced communication technology (icact) 2016 jan 31 (pp. 814-817). ieee. [8] west n, roy t, o'shea t. wideband signal localization with spectral segmentation. arxiv preprint arxiv:2110.00583. 2021 oct 1. [9] al-rawi m, materka a. ‘voiced/unvoiced speech signal segmentation using wavelet analysis.’ computational intelligence and applications. 23:85, (1999). [10] fearnhead p. exact bayesian curve fitting and signal segmentation. ieee transactions on signal processing, 53(6):2160-6, (2005). [11] saadatnejad, s., et al. ‘lstm-based ecg classification for continuous monitoring on personal wearable devices,’ ieee jour. of bio. and health informatics, (2019). [12] hussain, g., et al. ‘indoor positioning system: a new approach based on lstm and two stage activity classification,’ electronics, 8, (4), pp. 375, 2019. [13] shaikh, m., lee, k., and lee, c. ‘assessing the bug-prediction with reusability based package organization for object oriented software systems.’ ieice transactions on information and systems 100.1, 107-117, (2017). [14] shaikh, m. and lee, c. ‘aspect oriented re-engineering of legacy software using cross-cutting concern characterization and significant code smells detection.’ international journal of software engineering and knowledge engineering 26.03, 513-536, (2016). [15] hochreiter, s. and schmidhuber, j. ‘long short-term memory.’ neural computation 9.8, 1735-1780, (1997). [16] farooq, muhammad, juan m. fontana, and edward sazonov. "a novel approach for food intake detection using electroglottography." physiological measurement 35.5 (2014): 739. [17] farooq, muhammad, and edward sazonov. "a novel wearable device for food intake and physical activity recognition." sensors 16.7 (2016): 1067. [18] rachakonda, laavanya, saraju p. mohanty, and elias kougianos. "ilog: an intelligent device for automatic food intake monitoring and stress detection in the iomt." ieee transactions on consumer electronics 66.2 (2020): 115-124. [19] b. dong and s. biswas, "wearable diet monitoring through breathing signal analysis," 2013 35th annual international conference of the ieee engineering in medicine and biology society (embc), osaka, japan, 2013, pp. 1186-1189, doi: 10.1109/embc.2013.6609718. [20] nguyen, dzung tri, et al. "swallownet: recurrent neural network detects and characterizes eating patterns." 2017 ieee international conference on pervasive computing and communications workshops (percom workshops). ieee, 2017. [21] greff, k.; srivastava, r.k.; koutnik, j.; steunebrink, b.r.; schmidhuber, j. lstm: a search space odyssey. ieee trans. neural netw. learn. syst. 2017, 28, 2222–2232. [22] yang, jun, and fei wang. “autoensemble: an adaptive learning rate scheduling based deep learning model ensembling.”, ieee access 8 (2020): 217499217509. an energy efficient crypto suit for secure underwater sensor communication using genetic algorithm vol. 5, no. 1 | january – june 2022 sjet | p-issn: 2616-7069 |e-issn: 2617-3115 | vol. 5 no. 1 january – june 2022 1 investigation on high reliability wireless communication of underwater sensor networks for submerged acoustic correspondence atif ishtiaq1*, sheeraz ahmed1 asif nawaz2, muhammad adil1, zeeshan najam3, shahid latif4, malik taimur ali1, mohsin tahir4 abstract: underwater sensor networks (uwsns) has been the hot area of communication and research in the recent years and is finding its applications in a wide range of acoustic correspondences. notwithstanding, contrasted and the earthly condition, the marine condition is intricate and inconsistent, so correspondence in this condition is extremely troublesome. this article has directed a top to bottom conversation and survey of submerged specialized techniques and organization advances, (for example, submerged acoustic correspondence, submerged optical correspondence, and steering conventions and media access control, and submarine multimodal transport organizations. this article additionally talks about the accomplishments of highunwavering quality submerged correspondence innovation, and there are not many difficulties in managing submarine organizations. no such detailed work exists in literature which has addressed the concept of submerged acoustic communication. keywords: underwater wireless sensor networks, multimodal communication, acoustic communication, optical communication, underwater routing protocol, underwater mac protocol. the 21st century is the hundred years of the sea, and sea nations critically need to investigate and secure the sea. marine topographical investigation, oil extraction, and ecological observing require stable submerged organizations. simultaneously, the early admonition framework for characteristic marine fiascos and marine asset multiplication likewise advanced the improvement of marine computerization. the reason for an exceptionally solid marine organization is the highlight point submarine a correspondence framework with fast, low piece mistake rate (ber), long correspondence range, and low 1department of computer science, iqra national university, peshawar, pakistan. 2faculty of engineering higher college of technology dubai, uae 3department of electrical engineering, mns university of engineering & technology, multan, pakistan 4department of electrical engineering, iqra national university, peshawar, pakistan corresponding author: sheerazahmed306@gmail.com force utilization can be figured it out. different strategies for correspondence in a submerged situation have been proposed: submerged acoustic correspondence (uac), submerged optical correspondence (uoc), electromagnetic correspondence, gravity wave correspondence, quantum correspondence, and attractive field correspondence. be that as it may, truth be told, just uoc and uac can be utilized in submerged situations [1] [2], also, other specialized strategies are still in the research center check stage. uac is presently the most adult specialized technique utilized in submerged situations. the speed of sound sent mailto:sheerazahmed306@gmail.com investigation on high reliability wireless communication of underwater sensor networks for submerged acoustic correspondence (pp. 1 18) sukkur iba journal of emerging technologies sjet | vol. 5 no. 1 january – june 2022 2 submerged can arrive at 1500 m/s. the constriction is incredibly low, and the sound lessening coefficient between 1 hz and 50 khz is around 104 db/m to 102 db/m. the correspondence speed of under 1000 m can arrive at a few m/s [3]. sound waves can travel a great many kilometers low recurrence and high forces are the main approaches to accomplish significant distance submerged correspondence. notwithstanding, in spite of the fact that uac has the upside of permitting significant distance correspondences, it likewise has numerous disadvantages. for instance, its proliferation delay is long, in light of the fact that the spread speed of submerged sound is five significant degrees lower than radio recurrence (rf) speed. the state maritime organization necessitates that when a torrent cautioning happens, the sea perception organization ought to send the notice data inside 3 seconds, else it will inconsequential. clearly, uac can't meet this prerequisite. another significant imperfection of uac is inadequate data transfer capacity assets. in correspondence, the most significant issue is transfer speed. the immediate advantage of more prominent data transfer capacity is that it can enormously speed up. moreover, the commotion created because of the adaptability and unpredictability of the submerged condition, it extraordinarily meddles with uac, and the versatility of submerged hubs causes the doppler impact. the seabed limit, water limit and diverse geographic conditions in the sea cause multipath impacts, which represent a significant test to excellent amphibian correspondence. uoc is viewed as an enhancement to uac. the speed of optical correspondence can arrive at several m/s. be that as it may, since the light in the water rots quickly, the spread separation of the light in the submerged condition just a couple hundred meters. bluecom submerged optical correspondence framework can arrive at 20mbps. the submerged transmission speed is under 200 m [4]. the ambalux framework can arrive at a transmission speed of 10 mbps. the most extreme submerged separation is 400 m [1] [5]. with single-photon torrential slide diodes, uoc can accomplish transmission in a moderately perfect water condition, a separation of 500 m submerged [6]. despite the fact that this permits fast submerged through information transmission, uoc advances exacting prerequisites on the earth and the water nature of the two hubs acknowledge highlight point correspondence. the main condition is that the two correspondence hubs are inverse stable. during this time, the transmitter and collector must be unequivocally adjusted; something else, information transmission will be influenced dangerous demolition. the water quality in the earth incredibly influences optical correspondence on the grounds that, in sloppy water, the recipient can't get constant light signals. at the end of the day, information about water quality condition is an essential for deciding if uoc is relevant. submerged rf correspondence has been considered for submerged correspondence. since water retains electromagnetic waves, rf waves can just infiltrate a profundity of around 7 m [7]. as the frequency builds, the infiltration capacity of electromagnetic waves in water expands, arriving at 200 m. in any case, in super low recurrence rf correspondence, the transmission speed is decreased. it takes about 30 minutes to communicate the message, and the framework can just spat simplex mode. because of the enormous frequency, the reception apparatus of the transmitter must be several kilometers in length. this is clearly outlandish in the organization. we won't examine the submerged uses of rf correspondence in this article. these correspondence advancements essentially decide the strength and unwavering quality of submerged sensor organizations. obviously, there are different elements that influence the dependability of submerged sensor organizations, for example, steering conventions and macintosh conventions on the organization layer. we will examine these procedures in detail in the accompanying sections. our primary commitments are as follow: • elements influencing the unwavering quality of submarine organizations, including investigation on high reliability wireless communication of underwater sensor networks for submerged acoustic correspondence (pp. 1 18) sukkur iba journal of emerging technologies sjet | vol. 5 no. 1 january – june 2022 3 correspondence advancements and organizations innovation, exploration and investigation. • we have directed a thorough report on the most recent condition of submerged interchanges and its improvement of the presentation favorable circumstances of the submarine multimodal transport organization and proposals for the future advancement of submarines organization presentation. the ai used to send submerged information is additionally examined. • we examined the information transmission network helped by auv in a creative manner. as an exceptional submerged information transmission structure, we dissect its favorable circumstances and issues in the organization. • we talked about the difficulties and uncertain issues confronting the future advancement of submerged information transmission, including correspondences and networks, and propose arrangements that we believe are achievable. the remainder of this article is composed as follows. in the subsequent part, we talked about submerged correspondence innovations, including uac and uoc. in the third segment, we considered the organization in the submerged condition. the fourth area presents a few difficulties and remarkable issues. at long last, the fifth part advances a few ends and assessments about future examination. this part examines uac and uoc in detail, and uncovers a few factors that influence information transmission at various occasions correspondence innovation is applied to submerged arrangements. 2.1 underwater acoustic communication toward the finish of the nineteenth century, submerged acoustic frameworks were first broadly utilized by the military [15]. in 1945, the u.s. naval force's submerged acoustics research center planned a down to earth submerged telephone. because of specialized restrictions around then, the single-sideband adjustment innovation of the simple balance framework utilized in submerged phones utilizes a transporter recurrence of 8.33 khz, and its correspondence separation may arrive at a few kilometers. thusly, the submerged telephone utilizing recurrence tweak innovation has a transporter recurrence the khz has been effectively evolved. since the simple adjustment framework can't lessen the blurring and sign twisting brought about by the exceptional intricacy of the submerged sound channel, the presentation of the framework is extremely restricted. in the next decades, with the fast advancement of sign preparing innovation and with the continuous improvement of balance innovation, computerized balance innovation has been applied to uac. at present, the advancement of uac is restricted by adjustment innovation. old advanced simple regulation sound handling (dsp) and current symmetrical recurrence division multiplexing (ofdm) balance innovation both are gotten from earthbound correspondence frameworks. these advances can hypothetically be utilized in submerged correspondence frameworks. experience and reasonable application have additionally demonstrated this point. in 2008, milica and baosheng [8, 9] examined the use of ofdm innovation in uac framework, discovery. accordingly, darn et al. [10] ofdm entwined various access proposition (ofdm-idma) correspondence through submerged acoustic channels makes uac adjustment innovation more differentiated. with the advancement of submerged correspondence adjustment innovation, uac has gotten more dependable. be that as it may, the submerged acoustic channel is viewed as one of the most firm channel conditions, and its intricacy and inconstancy present impossible difficulties for solid data transmission. investigation on high reliability wireless communication of underwater sensor networks for submerged acoustic correspondence (pp. 1 18) sukkur iba journal of emerging technologies sjet | vol. 5 no. 1 january – june 2022 4 2.1.1 channel model the usage of the channel model incredibly benefits the hypothetical examination of uac and legitimately influences its quality. the submerged acoustic channel changes and changes after some time, and the direct examples in various oceanic conditions are additionally extraordinary. we have recorded some submerged acoustic channel models and clarified them in more detail. [11] proposed a straightforward numerical model for channel commotion, multipath impacts, and constriction. table 1 highlights the features of various channel models available in literature. path attenuation model: 𝐴(𝑙, 𝑓) = 𝑙𝑘 𝑙𝑟 ∝ (𝑓)𝑙−𝑙𝑟 (1) where f is the sign recurrence and l is the transmission separation regarding some 𝑙𝑟 . the way misfortune example models the spreading misfortune and its standard qualities are between two targets. noise model: 𝑆𝑁𝑅 (𝑙, 𝑓) = 𝑆𝑙(𝑓) 𝐴(𝑙,𝑓)𝑁(𝑓) (2) where 𝑆𝑙 (𝑓) is the power spectral density of the transmitted signal. multipath model: 𝐻𝑝 (𝑓) = 𝜏𝑝 √𝐴(𝑙𝑝,𝑓) () speaks to the recurrence reaction of the pth way. proposed a numerical model of an acoustic direct situated in a shallow water seaside condition. in the model, submerged acoustic weakening, mathematical dissemination, assimilation, signal base, and surface bob are thought of geometric diffusion attenuation model: 𝑇𝐿𝑔𝑒𝑜 = 𝑘 × log 𝑙 () where k is a consistent coefficient. in this model, dissemination can be isolated into roundabout dispersion and circular dissemination, and the k esteem is then 10 and 20, separately. 𝑙 is the separation between the beneficiary and the transmitter. infrared vitality is created when the transmitter performs acoustic regulation. at the point when the vitality transmits outward, the sound wave is constricted. the model is 𝑇𝐿𝑎𝑏𝑠 = 𝛼 × 𝑙 ′ × 10−3 () where ∝ = 𝐴1𝑃1𝑓 2 𝑓2+𝑓1 2 + 𝐴2𝑃2𝑓 2 𝑓2+𝑓2 2 + 𝐴3𝑃3𝑓 2 () where α is the weakening coefficient. the model thinks about the ph, temperature, and saltiness in the submerged condition as boundaries. table i. features of channel models models ef ph t s oc hp description path attenuation [11] √ √ √ √ focuses on the signal attenuation between the input and output; also studies the factors affecting signal attenuation, improving the accuracy of the model investigation on high reliability wireless communication of underwater sensor networks for submerged acoustic correspondence (pp. 1 18) sukkur iba journal of emerging technologies sjet | vol. 5 no. 1 january – june 2022 5 noise [11] √ a general model of noise used to measure the effect of noise on data transmission multipath [10] √ √ measure the effect of different paths under multipath effect on communication doppler power spectrum [12] √ √ analyze the intersymbol interference caused by the doppler shift bellhop [13] √ used to calculate the propagation loss of a certain sound line ef: empirical formula, s: salinity, oc: ocean current, hp: hydraulic pressure the above submerged acoustic channel model incorporates a few significant models: sound way weakening, commotion, multipath, and doppler. the lessening of the uac way is influenced by numerous elements, for example, recurrence, seawater temperature, saltiness, profundity and ph, infrared dissipating, and multipath dispersing. the constriction model proposed in [11] utilizes lessening coefficients to fit the inexact useful connection between submarines. the sound sign imparted and the sign got. because of the fitting capacity, the channel model shows a major contrast from the real channel. notwithstanding, the moderation model has more extensive materialness than the alleviation model proposed by milica. for the most part, the clamor in uac establishes added substance commotion. the least complex and best approach to portray the commotion is the sign to-clamor proportion (snr) [11]. the model summed up above is through investigation the movement condition of the submarine hub. in spite of the fact that multipath and doppler impact models can be developed, it is as yet hard to settle the high ber of uac. by depending on balance innovation, the counter channel and hostile to commotion weakening innovation can be incredibly improved. notwithstanding, for the doppler impact and multipath impact, the strategy or calculation notwithstanding the adjustment, different advancements are expected to improve correspondence execution, for example, spread range innovation, evening out innovation, and synchronization innovation. in the following part, we will investigate research on multipath and doppler impacts. 2.1.2 multipath effect, doppler effect, and orthogonal frequency-division multiplexing technology research the multipath impact that exists in practically all ground and submerged correspondence advancements is a significant factor prompting fast sign constriction. since the signs from various ways show up at the recipient at various occasions, on account of stage mistakes, the superposition of the signs will cause critical twisting or constriction of the got signal, which may prompt piece blunders. genuinely influence the solid transmission of information. . there are numerous strategies to forestall the impacts of multipath on the earth, for example, those that can improve the exactness of collector telemetry and time-space balance, and those that utilization ofdm adjustment. so as to improve separation exactness and time-area evening out, situating and time synchronization innovations are required. however, dynamic the geography of the investigation on high reliability wireless communication of underwater sensor networks for submerged acoustic correspondence (pp. 1 18) sukkur iba journal of emerging technologies sjet | vol. 5 no. 1 january – june 2022 6 submarine organization makes it hard to acquire exact situating and time synchronization for this situation condition [12]. ofdm balance is the best method to acknowledge multipath opposition submerged and can improve the submerged information transmission rate. the ideal submerged acoustic organization can be accomplished in the accompanying manners consolidates media access control (macintosh) and security instruments [13]. in spite of the fact that ofdm shows incredible presentation regarding multipath impedance, it will be seriously influenced by the doppler impact. the doppler impact in submerged correspondence is brought about by the recurrence balance brought about by the sporadic development of submerged hubs or vehicles. doppler move uncovers that when the recipient is before the sound source when the (hub) moves in a particular bearing, the frequency of the got signal is packed comparative with the frequency of the transmitter, and the recurrence is higher, and the other way around. as the hubs move quicker, the doppler impact increments significantly. in extreme cases, this can cause bit mistakes and correspondence interferences. ofdm is as yet the best correspondence tweak method that adjusts the attributes of the channel and the submerged condition. the investigation. the work to improve the productivity of ofdm innovation in submerged correspondence is still in progress. mahdi et al. the presentation of various info (mimo) ofmd frameworks dependent on quick fourier change (fft) and partial fourier change (frft) is looked at and examined [14]. despite the fact that the intricacy of frft and fft is comparably, in all multipath submerged conditions, the exhibition of the previous is superior to the last mentioned, while in a level blurring condition, their presentation is the equivalent. accordingly, the frft-based mimo-ofdm framework is a serious framework. because of the lackluster showing of ofmd frameworks that are not coded in blurring channels, [15]. the submerged exhibition of ofdm convolutional coding framework is considered. coded modem appeared in recreation. better than the underlying matlab library, the coding increases of added substance white gaussian commotion (awgn) and rayleigh channel are 0.635 db and 1.45 db (when ber is 10-1). trials have indicated that under helpless equipment conditions, convolutional coding (cc) ofdm can deliver better execution. coordinated channel (mf), zero power (zf) and least mean square mistake (mmse) equalizers can be utilized for channel evening out. nonetheless, every one of these equalizers has inconveniences that influence the correspondence execution of the framework: in mimo settings, the presentation of mf will be undermined, and the zf equalizer will experience the ill effects of clamor upgrade and the mmse equalizer must gauge the snr to work appropriately. khaled et al. gives a joint low-intricacy regularized zf equalizer and transporter recurrence balance remuneration framework. the proposed balance calculation utilizes consistent regularization boundaries to improve the commotion upgrade issue and framework intricacy. ofdm is touchy to doppler impact. the recurrence remuneration of numerous ofdm frameworks is an overall strategy to kill the doppler impact by applying downexamining and leftover transporter recurrence counterbalance pay. shingo, etc. a strategy for extending the testing extent and re-inspecting by estimating the doppler standard deviation is proposed. the conventional strategy accept that there is a consistent doppler recurrence move in the correspondence information outline, however in a genuine situation, the general speed between the sending and getting unit will change, and the doppler move will likewise vary. this strategy can adequately tackle this issue and improve the framework execution, or ber. multi-transporter adjustment is a noteworthy component of the ofdm framework, and the symmetry between the transporters is an essential to guarantee great execution of the ofdm framework. at times, symmetry between sub-transporters on a period shifting channel is lost, coming about in between transporter obstruction (ici). postinvestigation on high reliability wireless communication of underwater sensor networks for submerged acoustic correspondence (pp. 1 18) sukkur iba journal of emerging technologies sjet | vol. 5 no. 1 january – june 2022 7 fft and pre-fft are two arrangement strategies to manage this issue. the post-fft technique incorporates block adjustment or sequential leveling of the sign created between ici subsequent to demodulating the sign [15]. pre-fft technique 5 applies recurrence balance pay to the sign before demodulating the sign to kill non-symmetry between subtransporters [16]. a joined weight figuring calculation dependent on include disintegration is proposed. contrasted and existing versatile techniques, this calculation can forestall mistake spread and take out the prerequisite for boundary modification. this strategy ensures the general optimality under the supposition of narrowband doppler. the ideal weight vector for neighborhood fft demodulation is acquired through the eigenvector related with the littlest eigenvalue of the pilot recognition mistake lattice. the calculation can likewise be legitimately stretched out to sub-band computations to make up for wideband doppler impacts. in the above examination, it is discovered that uac is the most experienced and the most wellknown innovation is ofdm. this is fundamentally in light of the fact that ofdm can accomplish fast information transmission and can oppose multipath normally at low acoustic wave proliferation rates. despite the fact that the ofdm framework is delicate to the doppler impact, the adjustment innovation. as of late, it has been proposed to cure this deformity. the consequences of ofdm coding exploration and demodulation execution investigation ici, frft, and fft help make the ofdm submarine correspondence framework more like an ideal framework and improve the dependability of information transmission 3.1 underwater routing submerged information transmission can't simply utilize basic highlight point information transmission. so as to acknowledge information transmission, brilliant correspondence innovation ought to be utilized to set up a solid submarine organization in the assigned ocean region. the directing convention is the fundamental convention of the correspondence organization, which is significant for the acknowledgment of the organization information bundle transfer measure. broad examination has been led on submarine directing conventions, and many submarine steering convention calculations exist. since the development and utilization of submarine organizations are still in their earliest stages, there are still not many submarine organizations that can be concentrated through analyses. since it is hard to lead directing examination in a real situation, just a couple steering conventions have been tried in this condition. the excessive cost of submarine organization hubs is another motivation behind why the organization comprises of just a couple of hubs [17]. the plan of submarine steering conventions is more convoluted than that of earthbound directing conventions. the geography of the earthly organization is a twodimensional plane, while the geography of the submarine organization is a three-dimensional [18]. moreover, submarine directing is consistently powerful, and submarine steering is consistently static. along these lines, it isn't suitable to completely recreate the ground steering convention to the submarine organization. likewise, submarine steering faces hub development, power utilization, and different difficulties [19]. specifically, submarine directing experiences similar weakness issues as land steering, and it is more hard to explain in submarine organizations [17] . in the accompanying segment, we will survey and sum up as of late created steering conventions so peruses can comprehend the current advancement status of submarine directing conventions. figure 1 shows the model of the submerged sensor organization. 3.1.1 location-based routing protocols in the early examination on submarine directing, the presence or nonattendance of hub area data in the organization is viewed as the principle highlight those partitions submarine steering conventions into two sorts. the ordinary portrayal of area-based steering is the vector-based vehicle convention (vbf) [16], and the average portrayal of non-area based directing is the profundity based investigation on high reliability wireless communication of underwater sensor networks for submerged acoustic correspondence (pp. 1 18) sukkur iba journal of emerging technologies sjet | vol. 5 no. 1 january – june 2022 8 directing convention (dbr) [17]. reason for the vbf understanding it includes utilizing the known area data of every hub to build up a powerful information interface from the source hub to the accepting hub. the fundamental thought is to set up a barrel shaped virtual line between the source hub and the collector hub. the hubs between the source hub and the sink hub in the pipeline are applicant hand-off hubs for sending parcels. the size of the virtual line built up by the convention is a key factor influencing the organization. in the event that the pipeline extend is excessively huge, the quantity of jumps and force utilization will increment unnecessarily, while too short a range will cause correspondence interference and parcel misfortune. despite the fact that the convention is profoundly versatile in unique 3d submarine organizations, there are as yet significant issues to consider: hub power utilization and meager organizations. so as to take care of these two issues. proposed the vbf jump by-bounce (hh) convention in [18]. the engaged shaft directing (fbr) convention was proposed [19]. hh-vbf tackles the exhibition issue of vbf in scanty organizations. this strategy utilizes a jump bybounce virtual line fig. 1. model of underwater sensor network figure 1 shows the model of an environment of uwsns. the source hub passes the information to the in its virtual pipeline, the source hub doesn't partake in ensuing information transmission. the following bounce hub is set up its own free channel shows up at the accepting hub until the information bundle is effectively sent to the following jump hub. fbr is a directing convention dependent on power inclusion, which utilizes various degrees of communicate power during transmission. in the directing cycle, the sending hub sends an information parcel demand with a particular communicate power level to its neighbors. in the event that the sending hub gets a transmission approval parcel (cts) from the neighbor, it will be sent to the neighbor hub with a cts reaction; in any case, if the cts isn't gotten, the communicate power level is expanded to the following force level. rehash this cycle until the cts parcel is effectively gotten. be that as it may, the consistent trade of solicitation to send (rts)/cts bundles will cause delays. likewise, fbr additionally has situating issues. 3.1.2 non-location-based routing protocols in submarine organizations, it is here and there hard to decide the area data of hubs. directing conventions dependent on the spot data are profoundly subject to subsea situating calculations, which represents a considerable test in subsea networks. in this way, steering conventions dependent on non-area data have useful worth. the first non-area data based steering convention proposed by yan et al. for submerged conditions is dbr [17]. this convention just thinks about one boundary in information transmission, specifically the profundity of the hub. in the organization model, the well hubs are situated on the water surface, and the seabed hubs are dispersed at various profundities haphazardly apportioned. after the information bundle is produced, the hub sends the information parcel upward as per the profundity, and ceaselessly figures the profundity contrast between the hub and the nearby hub during the estimation. the investigation on high reliability wireless communication of underwater sensor networks for submerged acoustic correspondence (pp. 1 18) sukkur iba journal of emerging technologies sjet | vol. 5 no. 1 january – june 2022 9 transmission cycle guarantees that information bundles must be communicated upwards. since the convention just uses profundity as a norm for information transmission, hubs with shallower profundities will take an interest a lot in information transmission, and in this manner expend more power and neglect to run quicker. moreover, the dbr convention doesn't give a more viable next-bounce hub choice. the h2-dbr convention [20] and the eedbr (vitality productivity dbr) convention proposed later tackled the above issues and significantly improved the exhibition of the dbr convention. in 2014, wahid et al. the dbr convention was created to actualize a dependable and vitality sparing directing convention dependent on physical separation and leftover vitality (r-erp2r). this subsea directing convention is normally founded on physical separation [21]. it replaces the profundity figuring in the dbr convention with the count of the physical separation between the source hub and contiguous hubs. such a calculation is more appropriate for submerged grouping sensor organizations. it considers the force utilization of submarine hubs on a worldwide scale. thusly, the exhibition of this convention is better than eedbr as far as organization information transmission and organization life. its hello packet formation is shown in figure 2. fig. 2. hello packet 3.1.3 energy-based routings in 2018, majid and ahmad proposed a solid and vitality sparing weight based directing convention (re-pbr) [21] and an improved vbf convention [22]. the re-pbr convention presents a few boundaries, for example, remaining vitality, connect quality record (lqi), and snr esteem. to start with, the connection quality worth is added to the transfer steering choice calculation. reenactment tests show that contrasted and eedbr and dbr, the start to finish deferral and organization lifetime have been fundamentally improved. contrasted and the first vbf in the arrangement, ahmed's upgraded vbf convention thought about the rest of the vitality, and he inventively proposed a unique virtual line technique to improve vbf execution. the convention utilizes data, for example, remaining vitality and hub position changes as boundaries to powerfully decide the virtual line sweep of the source hub to adjust to the precarious submerged condition. so as to additionally improve the endurance season of the submarine organization. an improved dbr-based vitality recuperation dbr convention (ehdbr) [23] is proposed, which utilizes the accompanying information bundles to gather vitality in the acoustic correspondence recurrence band to stack hub information. in principle, the life expectancy of the submarine organization can be broadened inconclusively. numerous examinations have contemplated the force utilization of submarine hubs, which likewise shows that in the field of submarine correspondence organizations, the force utilization of hubs is an essential issue. as of late, numerous explores on the force utilization of correspondence organizations or hubs have been accounted for in the writing, just as many steering conventions [24] recommendations and upgrades. 3.1.4 vh-based routing protocols the data vacuum (vh) issue is a significant issue in the presentation of submarine organizations, and it likewise represents a significant test to the designers of steering conventions. among the numerous articles audited, just a couple of considered the issue of submerged vh. by and large, most steering conventions can settle on one of the accompanying two choices while experiencing vh: the first is to dispose of information parcels after numerous programmed recurrent solicitation (arq) conventions have fizzled. there is no reaction, and the second is to build the organization over-burden to sidestep the data weakness. these strategies can't impeccably tackle the vh issue, yet can adequately lessen the unpredictability of the investigation on high reliability wireless communication of underwater sensor networks for submerged acoustic correspondence (pp. 1 18) sukkur iba journal of emerging technologies sjet | vol. 5 no. 1 january – june 2022 10 steering calculation. lately, many examination results on data weaknesses have been accounted for. in [25], the principal complete stateless shrewd directing convention (sorp) was proposed. it utilizes a detached cooperation technique and locally identifies weaknesses and hubs caught in various regions of the organization geography during the steering cycle. it likewise receives another plan to accomplish a versatile transmission region that can be balanced and supplanted by the nearby thickness and the area of applicant transmission hubs, in this way improving vitality proficiency and dependability. nadeem et al. two conventions for preparing vh are proposed: impedance delicate directing convention (intar) and solid obstruction touchy steering convention (reintar). there are just a couple of contrasts between the two conventions. this understanding sets up a two-venture information interface. in the initial step, the source hub communicates a welcome message to discover all the ways that can arrive at the getting hub and store them. the welcome bundle incorporates id, numnequart, timestamp, distneighbors, and hopsink. subsequent to refreshing the accessible information authoritative, the source hub decides the following jump hub by ascertaining the estimation of the cost work (cf): 𝐶𝐹(𝑗) = 𝐷𝑖𝑠𝑡 (𝑖,𝑗) 𝐻𝑜𝑝 (𝑗)×𝑁𝑒𝑖𝑔ℎ𝑏𝑜𝑟 (𝑗) (7) where hop( j) is the quantity of skips of the j-th potential sending center point (pfn) from the sink, neighbor (j) is the quantity of neighbors of the j-th pfn, and dist(i, j) is the partition between the j-th pfn and source center point i. the difference between the reintar show and the intar show is that significance information is added to the past holle. the show can sufficiently deal with the information opening issue and shows a particular improvement in network execution. 3.1.5 routing protocols based on machine learning ai is a hotly debated issue of flow exploration, and learning calculations are viable with submerged correspondence organizations. applying ai techniques to submarine organizations has become a significant method to tackle its key issues. since the conventional ground convention can't adjust to the submerged condition, the presentation of the non-wise steering convention in the submerged organization is as yet not acceptable. a proficient and adjusted q-learning vitality utilization information assortment directing convention qleebdg [26] is proposed. the convention depends on fortification learning and plans to adjust the force utilization of certain accumulated hubs in the organization with the goal that one hub won't cause network interference or diminish power utilization for an enormous scope. organization inclusion rapidly kicked the bucket because of extreme use. there is a genuine defect in fortification realizing, which is known as a dimensional emergency. fortification adapting needs information for preparing. the dynamic cycle is the way toward learning nature. the q esteem table is utilized to store current natural data. at the point when the condition of nature has just one measurement, the worth table q just needs one line and n segments to record all the data. at the point when nature state is twodimensional, a n*n table is expected to record data. when there are three measurements, a three-dimensional block cluster is expected to store the information. shouldn't something be said about the four measurements? support learning is hard to oversee. nonetheless, the submerged condition is exceptionally unpredictable, the quantity of states can arrive at thousands, and the quantity of measurements can arrive at many measurements. all directing calculation dependent on fortification learning. every hub is permitted to record the q benefit of neighboring hubs dependent on the prize capacity, which significantly decreases the data put away in the q esteem table. the investigation on high reliability wireless communication of underwater sensor networks for submerged acoustic correspondence (pp. 1 18) sukkur iba journal of emerging technologies sjet | vol. 5 no. 1 january – june 2022 11 organization is upgraded locally, not around the world. in view of the previously mentioned issues brought about by support learning, su et al. proposed a steering convention dependent on q-learning (dqn), dqelr vitality, and dormancy affectability [27]. the convention utilizes the base force utilization and the briefest postponement as the objective capacity of the organization so the organization keeps up a brief pause under powerful geography conditions and augments its administration life. profound fortification learning is a mix of support learning and profound neural organizations. profound neural organizations can separate highdimensional data includes, and can consummately conquer the dimensionality emergency of fortification learning. the info state and activity in the dqelr convention is around 1300 tuples, and figure 3 shows a detailed map of various underwater routing protocols till date. the neural organization utilizes a five-dimensional model (counting the predisposition term b1) and three concealed layers of a completely associated network. this convention can generally inexact the best arrangement, and the test results are marginally improved contrasted and the vitality proficient and effective life-cycle q-getting the hang of steering convention (qelar) and vbf [27] [16]. the examination in the writing likewise called attention to an issue: on the grounds that the neural organization requires a ton of information for preparing, the convention requires a support learning calculation to become familiar with nature progressively, and the learning cycle has a long postponement, which may take a few hours or more it requires some investment to arrive at the neural organization the condition of combination. to dodge this issue, the dqelr convention utilizes a blend of disconnected and web based preparing; before the proper use of the convention, disconnected preparing can extraordinarily accelerate the calculation's combination speed. the submarine organization model given in [27] [16] is a unique organization hub model. the proposed directing convention must have the option to completely ensure the dependable information transmission of the organization with high flexibility. fig. 3. routing protocol for uwsns [27] at the point when the organization geography changes progressively. furthermore, nadeem et al. fortification learning is additionally used to dodge the utilization of neighboring hub innovation qleebdg-and [22] in the directing convention of void hubs. apply ai techniques to subsea directing, which furnishes each hub in the organization with certain canny dynamic capacity, it is a compelling answer for submerged courses and a hot examination subject. at last, we give a characterization outline of directing conventions and sum up the points of interest and weaknesses of the classifications depicted in table 2. table ii. advantages and disadvantages of underwater network types cat description layered network ad: low complexity, easy to implement, low demand for network toplogy. da: difficult to control energy investigation on high reliability wireless communication of underwater sensor networks for submerged acoustic correspondence (pp. 1 18) sukkur iba journal of emerging technologies sjet | vol. 5 no. 1 january – june 2022 12 consumption and deal with voids clustering network ad: strong scalability, balanced energy consumption. da: algorithm complexity higher, and the netwok performance is affected by protocols multimodal network ad: effectively improve network performance. da: higher requirements on network topology and required better resource allocation algorithm auv ad: an effective method for big data transmission. da: high network latency 3.2 medium-access control protocols the media access control (mac) convention is a key innovation for network access. in this manner, as an exemplary issue in wired and remote organizations, broad exploration has been directed for a long time. there have been valuable explores on the macintosh convention of submerged acoustic recognition organizations. these examinations can be isolated by the channel access technique they talk about: asset assignment, asset rivalry, or blending. fig. 4. mac routing protocols for uwsns [25] resource allocation type mac protocol is divided into three main types: frequency division multiple access (fdma), time division multiple access (tdma) and code division multiple access (cdma). fdma realizes frequency division multiple access, orthogonal fdma (ofdma) protocol uses orthogonal frequency division; highlighted in figure 4. as innovation for advancing channel portion, cdma convention actualizes various access by spreading code distribution, while tdma convention executes different access by isolating time allotments, along these lines diminishing bundle dispute [23]. the focal thought of the asset serious macintosh convention is to seriously acquire remote channels for hubs that need to communicate information. they can be additionally partitioned into uncontrolled parcel conventions, single controlled bundle conventions, and handshake conventions. the principle thought of macintosh unchecked parcel convention is ''send is yours'', however it is anything but difficult to cause information bundle crash. salud [24] is a regular uncontrolled parcel convention. its allencompassing convention decreases clashes by consolidating channel checking [25], inferring the working status of neighboring hubs [25], isolating time allotments [26], and utilizing a handshake convention [27]. the focal thought of the single control information parcel macintosh convention is to utilize a solitary control information bundle to advise the adjoining channel that it is occupied. these conventions incorporate salud with notification ahead of time (salaam a) [28], submerged acoustic organization macintosh (uwan-macintosh) [19], and t-lohi convention [10]. in view of the t-lohi convention, by utilizing offbeat channel simultaneousness and straightforwardly partitioning the time allotment into the unit of the dispute time frame, the time division of the information parcel can be additionally diminished [11]. the handshake convention utilizes channel interference to trade two-way data and decreases the pace of bundle crashes by lessening the quantity of occupied channels. the most ordinary handshake investigation on high reliability wireless communication of underwater sensor networks for submerged acoustic correspondence (pp. 1 18) sukkur iba journal of emerging technologies sjet | vol. 5 no. 1 january – june 2022 13 macintosh convention is csma/ca [12]. in the submerged acoustic sensor organization, the issue of terminal introduction or covering up is intense. in this manner, a ton of exploration has been done on the handshake macintosh convention in submerged acoustic sensor organizations. when there is a concealed terminal issue, if a channel is distinguished to be idle, it doesn't really imply that the channel is accessible; comparatively, when there is an uncovered terminal issue, if a channel is identified to be occupied, it doesn't really imply that channel inaccessible. for the force utilization brought about via transporter detecting, a few conventions no longer use transporter detecting innovation. impact evasion different access (maca) [23] is the primary handshake convention that doesn't utilize the transporter course; channel arrangement is brought out straightforwardly through three-party exchange. in view of this, in the writing research [24], the steadiness methodology is utilized to additionally improve the convention execution. in the handshake convention, because of concealed terminal issues, parcel impacts generally happen at the collector level. thusly, so as to tackle the issue of shrouded terminals, a few conventions broaden the transmission season of control parcels and guarantee that all influenced neighbor hubs can get related control data before sending information bundles. fama convention [25] is the principal convention to decrease bundle impacts by utilizing postpone control parcels. in view of this, a few techniques have been grown, for example, time allotment division [66], sending caution information parcels [27], and planning information transmission start time and end time [28]. used to additionally take care of the issue of concealed terminals. a hub doesn't comprehend the information transmission necessities of different hubs, yet indiscriminately sends information as indicated by its own needs. in related examinations, spatio-fleeting irregularity has been utilized to improve channel usage and accomplish equal information transmission between numerous sets of hubs through the accompanying or comparative techniques: transmission settings of information bundles and control parcels [19], foundation and arrival of hub work schedule [20], two-way relative information transmission [21], (various) and multi-bunch transmissions [22], postponed reaction to rts order parcel and saved the following information transmission ahead of time [24]. 3.3 underwater multimodal network as per research on submarine organizations, it is difficult to develop a fast and solid submarine organization utilizing just a single specialized technique. the multimode submarine organization (mdun) in light of various specialized techniques is the most probable organization structure later on. it tends to be seen from figure 1 that the three correspondence modes exist together in the whole organization. the accepting hub is situated on the water surface, the base station of the stage is the focal point of information assembly, and the rf utilized for correspondence between the recipient and the base station is additionally utilized between the beneficiary and the collector. sink. the sink center point talks with the submarine center point and the submarine-helped selfadministering lowered vehicle (auv) through different repeat gatherings. right hand auv and lowered center points impart data in short partitions through uoc. the momentum meaning of submerged polymorphic organizations is muddled. at the point when a framework contains a lot of innovations that don't meddle with one another, it is characterized as a multi-mode [27]. roee proposed the routing protocol based on mdun [27]. the mdun discussed in this article is a submarine network using three different frequency bands. it is assumed that the three uac frequencies do not interfere with each other. table 3 shows the advantages and disadvantages of underwater resources. high, medium and low-recurrence uac structure a six-hub organization. high and medium recurrence hydrophones can communicate information at short and medium paces. low-recurrence submerged sounds can travel a significant distance. investigation on high reliability wireless communication of underwater sensor networks for submerged acoustic correspondence (pp. 1 18) sukkur iba journal of emerging technologies sjet | vol. 5 no. 1 january – june 2022 14 everything hubs can be furnished with different uac modulators of various recurrence groups, and there can be numerous connections between two contiguous hubs in the organization. another mdun model was proposed in [20]. the model uses three specialized strategies: uoc, uac, and electromagnetic waves. the general structure of the organization incorporates a getting hub, a subsea information source hub, and an assistant information offloading auv. table iii. advantages and disadvantages of underwater network resources cat description resource allocation ad: reducing packet conflict, easy to sleep, no hidden terminal issues, suitable for low power networks. da: cannot adapt to network topology flexibly resource competitive ad: no complex time synchronization or control scheduling algorithms required, adapt to the changes of network topology. da: conflict retransmission hybrid can effectively balance the advantages and disadvantages of the above two types the great hub is situated on the water surface and gathers information submerged. the submerged hub is fixed in the submerged recognition territory by a grapple chain to produce video data. information bundles are produced at a speed of 5 m/min, and the auv is utilized to empty submerged information. auv and submarine hubs have both uac and uoc capacities, and auv additionally has remote electromagnetic wave correspondence capacities. the submarine node sends control information to the auv through the uac to determine its path to the node. when visiting a node, the auv unloads the node data packet through the uoc, and then the auv surface and send the data packet to the receiving node through electromagnetic wave communication. the over two organization models speak to two common multi-top submarine organizations: auv doesn't help and auv helps polymorphic organizations. we accept that the submerged acoustic organization proposed by roee et al. is certainly not a genuine mdun. submarine organizations that utilization different media correspondence advancements are more assorted. its organization structure is delegate, rapid and short-separation, and a multi-mode network that consolidates significant distance and low-speed correspondence innovation can improve delay, throughput, power, and so on. contrasted and a solitary mode organization, the organization can guarantee solid information transmission. the prevalence of organization engineering can once in a while significantly improve network execution. for sea organizations, an unadulterated submerged acoustic wave organization can give adequate inclusion, however it can't guarantee the transmission of enormous information. an unadulterated uoc organization can send enormous information, however it can't ensure adequate sea inclusion. as of now, sea information is developing exponentially, and multi-mode submarine organization or heterogeneous submarine organization is a more great organization model. in the past segment, we referenced a multistate network model that utilizes auv to help offload information. auv gets to information source hubs by offloading data to the organization as per a specific calculation and performs information transmission of video data [21]. the auv access way calculation under this organization has become a key factor in network execution. adding auv to the submerged sensor organization will without a doubt improve the unwavering quality of its information transmission. at the point when the organization contains auvs, their number, way, and force utilization will influence network information transmission. at present, there are not many investigations on the submarine organization helped by submerged vehicles. in [22], auv way investigation on high reliability wireless communication of underwater sensor networks for submerged acoustic correspondence (pp. 1 18) sukkur iba journal of emerging technologies sjet | vol. 5 no. 1 january – june 2022 15 arranging in a polymorphic organization condition is evaluated, and a heuristic choice calculation is proposed, to be specific versatile covetous auv way search (gaap). gaap empowers auv to boost the data estimation of the arrange and adjust to crises that happen in the organization. the calculation in this article permits auv to communicate network information at a speed surpassing 80% of the hypothetical greatest. gaap performs well in arranging a solitary auv way, however as the quantity of auvs in the organization expands, the issue of rehashed admittance to hubs will influence the calculation, which enormously influences execution. the web. examination on submerged auv direction arranging shows that the direction choice strategy for submerged auv is a significant aspect of things to come submarine organization. auvhelped specialized technique has unrivaled points of interest of huge scope information transmission through customary specialized strategies. in auv-based submarine, multistate organizations, or heterogeneous organizations, a few auv way choice calculations, auv power streamlining, and clever way calculations actually should be fathomed. the issue of auv way arranging is basically a directing issue. in any case, it is unique in relation to steering. the directing calculation has not been applied to the way choice of auv, which makes this issue another examination theme. later on, submarine organizations will unavoidably incorporate auvs. auv way search examination can improve the unwavering quality of submarine organization information transmission. later on, the auv way choice convention in the submarine organization convention stack will turn out to be significant. in the marine environment, achieving solid information transmission is a troublesome test. in the following sections, we will discuss theories and methods used to transmit underwater data. figure 5 shows and summarizes the challenges and outstanding issues based on the current research phase. 5.1.1 underwater acoustic ommunication issues and challenges the benefit of uac in submerged correspondence is that it can understand significant distance correspondence, and the correspondence separation can arrive at several kilometers, yet there are not kidding abandons in the transmission rate, postponement, and ber. factors, for example, channel blurring and multipath impacts are significant issues influencing uac. in the flow research on uac, the issue of channel blurring can be successfully illuminated by applying adjustment innovation, however a solid channel model should be built up. so as to adapt to the multipath impact, ofdm innovation shows better execution yet requires assistant evening out innovation to address the doppler move. so as to adapt to the low correspondence rate, mimo-ofdm innovation is utilized to improve data transfer capacity use, and multi-radio wire innovation is utilized to expand the correspondence rate. huge advancement has been made lately it was fruitful in uac, however there are as yet numerous difficulties. above all else, the assorted variety and unpredictability of the submerged condition make it troublesome and unrealistic to display submerged acoustic channels, which requires solid submarines. acoustic channel assessment calculation. second, the high inactivity of uac is the most troublesome issue to tackle. fathom. at present, there is no powerful strategy to decrease uac delay, and no exploration identified with this issue has been directed. third, the security of uac is a central point of interest for the future utilization of submerged acoustic organizations. secure personality check system, solid coding innovation, and exact situating innovation will influence the security and the dependability of uac. 5.1.2 optical communication problems and challenges compared with uac, the two principle favorable circumstances of uoc are very high transmission rate and millisecond delay. notwithstanding, the short correspondence separation permitted by uoc is the principle investigation on high reliability wireless communication of underwater sensor networks for submerged acoustic correspondence (pp. 1 18) sukkur iba journal of emerging technologies sjet | vol. 5 no. 1 january – june 2022 16 obstruction to its turn of events. right now, the longest transmission separation that can be accomplished in a quiet submerged condition is just 500 m, meet the necessities of the canny sea organization. because of the utilization of light as a correspondence medium, uoc hubs are anything but difficult to uncover the area of the handset, which makes military security it is hard to accomplish mystery correspondence. what's more, the highlight point uoc framework requires high exactness alignment innovation, yet correspondence hubs regularly can only with significant effort keep up a steady situation in submerged environmental factors. on the off chance that the force framework is utilized to look after soundness, the vitality utilization of hubs will increment. fig. 5. challenges and issues of ocean data this will abbreviate its administration life and truly influence the effectiveness and soundness of information transmission. distributed. the specialized technique depends on a laser discharging unit, which devours a ton of vitality and expends a great deal of vitality. relies upon the water nature of the earth. to tackle this issue, the submerged correspondence framework. the utilization of diffuse light sources will be supplanted. however, the light intensity of the scattered light source is scattered [fig 5.]. this will cause data transmission distance, channel noise, throughput and ber to decline, so it cannot replace the application of point-topoint communication systems under certain circumstances. therefore, uoc systems should also be diversified. the complete use and networking of multiple uoc systems may be an important future theme. 5.2 networking the acknowledgment of submarine organizations is a definitive objective of submarine correspondence innovation applications, and the significance of building sea networks is self-evident. at the organization level, submarine directing is a significant issue in submarine organizations. as of late, there has been more examination on submarine steering than some other perspective. compared with traditional landbased routing, submarine routing presents more problems and challenges. generally, the topology of the terrestrial network does not cause height problems. in such an organization, directing calculations must be thought of and planned distinctly on a twodimensional plane, and the associations between network hubs are steady. nonetheless, in the submerged condition, the geography of the organization comprises a three-dimensional structure. to start with, it enormously expands the intricacy of the organization steering calculation, and second, the area of the hub is influenced by the sea and has gone through colossal changes. the flimsiness of the correspondence association among hubs and the vitality impediment of the hubs are significant difficulties in the plan of directing calculations. as of late, with the fame of ai, numerous scientists have proposed submerged steering calculations, submerged channel assessment strategies, and leveling calculations dependent on ai. calculations dependent on ai can successfully deal with the versatility of submarine hubs, data vh and hub power utilization. the impact of these calculations on voracious calculations will prompt more solid execution. keen calculations ordinarily require a great deal of information preparing and ground-breaking figuring power, which will without a doubt prompt all the more overhead on the organization. uac system can achieve higher coverage, but the investigation on high reliability wireless communication of underwater sensor networks for submerged acoustic correspondence (pp. 1 18) sukkur iba journal of emerging technologies sjet | vol. 5 no. 1 january – june 2022 17 communication rate is very low, while uoc system can achieve higher communication rate, but the coverage is smaller. the mudn form integrates uoc and uac to provide coverage and achieve high-speed local data transmission, but there are bottlenecks factors that affect latency and throughput still exist in the network. applying underwater auv to the transmission of auxiliary data in underwater networks can greatly alleviate these bottlenecks. although changing the network structure will improve performance, it will also bring about some problems, such as auv path planning and underwater acoustic and optical system resource allocation problems. according to underwater communication technology and network research, it can be concluded that after using reasonable deployment topology technology, the future of ocean data transmission will involve the multimode and heterogeneous characteristics of different communication technologies. the resources of network nodes and different areas of the network are different. in addition, there will be significant differences in the speed and quality of regional communication. in marine correspondence, there is no correspondence advancement, network structure, or show that can totally change in accordance with all application circumstances, so conventional assortment will transform into a sign of future correspondence associations. notwithstanding the sea, customary non-canny calculations additionally show evident deformities in the continually changing marine condition. manmade consciousness based organization convention calculations will assume a significant function later on sea organization. in this overview, we originally checked the current review records and foundation. we have examined submerged correspondence innovations, including uac and uoc, just as directing conventions and macintosh conventions. investigated and broke down the components influencing the dependability of submarine organizations, including correspondence innovation and organization innovation. next, we dissected the momentum research progress, submarine multi-mode uwsn, and auv helped uwsn. at long last, we zeroed in on the issues and moves that should be defeated in improving submerged information transmission later on. we trust this survey will support analysts and designers comprehend the possibilities and flow status of submerged information transmission, just as the difficulties it faces. references [1] z. zeng, s. fu, h. zhang, y. dong, j. cheng, a survey of underwater optical wireless communications, ieee communications surveys and tutorials 19 (1) (2017) 204-238. [2] s. jiang, on reliable data transfer in underwater acoustic networks: a survey from networking perspective, ieee communications surveys and tutorials 20 (2) (2018) 1036-1055. [3] g. tuna, v. gungor, a survey on deployment techniques, localization algorithms, and research challenges for underwater acoustic sensor networks, international journal of communication systems 30 (17). [4] c.-y. li, h. lu, w. tsai, z. wang, c. hung, c. su, y. lu, a 5m/25gbps underwater wireless optical communication system, ieee photonics journal 10 (3). [5] m. a. khalighi, m. uysal, survey on free space optical communication: a communication theory perspective, ieee communications surveys and tutorials 16 (4) (2014) 2231-2258. [6] j. shen, j. wang, c. yu, x. chen, j. wu, m. zhao, f. qu, z. xu, j. han, j. xu, single led-based 46m underwater wireless optical communication enabled by a multi-pixel photon counter with digital output, optics communications 438 (2019) 78-82. [7] u. m. qureshi, f. k. shaikh, z. aziz, s. m. z. s. shah, a. a. sheikh, e. felemban, s. b. qaisar, rf path and absorption loss estimation for underwater wireless sensor networks in different water environments, sensors 16 (6). [8] m. stojanovic, ofdm for underwater acoustic communications: adaptive synchronization and sparse channelestimation, in: proceedings of 33rd ieee international conference on acoustics, speech and signal processing, las vegas, nv, 2008, pp. 5288-5291. [9] b. li, s. zhou, j. huang, p. willett, scalable ofdm design for underwater acoustic communications, in: proceedings 33rd ieee international conference on acoustics, speech and signal processing, 2008, pp. 5304-5307. [10] j. aparicio, f. j. alvarez, j. urena, a. jimenez, c. diego, e. garcia, swell effect in shallow underwater acoustic communications, in: proceedings of 15th ieee international conference on emerging technologies and factory automation, univ basque country, fac engn, bilbao, spain, 2010. investigation on high reliability wireless communication of underwater sensor networks for submerged acoustic correspondence (pp. 1 18) sukkur iba journal of emerging technologies sjet | vol. 5 no. 1 january – june 2022 18 [11] s. milica, j. preisig, underwater acoustic communication channels: propagation models and statistical characterization, ieee communica¬tions magazine 47 (1) (2009) 84-89. [12] d. v. ha, v. d. nguyen, q. k. nguyen, modeling of doppler power spectrum for underwater acoustic channels, journal of communications and networks 19 (3) (2017) 270-281. [13] m. b. porter, l. jolla, the bellhop manual and user’s guide: preliminary draft. [14] k. m. awan, p. a. shah, k. iqbal, s. gillani, underwater wireless sensor networks: a review of recent issues and challenges, wireless communications and mobile computing. [15] c. chen, h. zhu, m. li, s. you, a review of visualinertial simultaneous localization and mapping from filtering-based and optimizationbased perspectives, robotics 7 (3). [16] s. jiang, state-of-the-art medium access control (mac) protocols for underwater acoustic networks: a survey based on a mac reference mode, ieee communications surveys and tutorials 21 (1) (2018) 96-131. [17] s. jiang, on securing underwater acoustic networks:a survey, ieee communications surveys and tutorials 21 (1) (2019) 729-752. [18] h. esmaiel, d. jiang, spectrum and energy efficient ofdm multicarrier modulation for an underwater acoustic channel, wireless personal communications 96 (1) (2017) 1577-1593. [19] a. abdelkareem, b. sharif, c. tsimenidis, adaptive time varying doppler shift compensation algorithm for of dm-based underwater acoustic communication systems, ad hoc networks 45 (2016) 104—119. [20] m. wen, x. cheng, l. yang, y. li, x. cheng, f. ji, index modulated ofdm for underwater acoustic communications, ieee communications magazine 54 (5) (2016) 132-137. [21] m. nassiri, g. baghersalimi, comparative performance assessment between fft-based and frftbased mimo-ofdm systems in underwater acoustic communications, iet communications 12 (6) (2018) 719-726. [22] k. ramadan, m. i. dessouky, m. elkordy, s. elagooz, f. e. a. el-samie, joint low-complexity equalization and carrier frequency offset compensation for underwater acoustic ofdm communication systems with banded-matrix approximation at different channel conditions, international journal of communication systems 31 (17). [23] s. yoshizawa, t. saito, y. mabuchi, t. tsukui, s. sawada, parallel resampling of ofdm signals for fluctuating doppler shifts in underwater acoustic communication, journal of electrical and computer engineering 2018 (2). [24] j. han, l. zhang, q. zhang, g. leus, eigen decomposition-based partial fft demodulation for differential ofdm in underwater acoustic communications, ieee transactions on vehicular technology 67 (7) (2018) 6706-6710. [25] c.-f. lin, h.-h. lai, s.-h. chang, mimo gs ovsf/ofdm based underwater acoustic multimedia communication scheme, wireless per¬sonal communications 101 (2) (2018) 601617. [26] j. wu, iterative compressive sensing for the cancellation of clipping noise in underwater acoustic ofdm system, wireless personal commu¬nications 103 (3) (2018) 2093-2107. [27] r. diamant, p. casari, f. campagnaro, fair and throughput-optimal routing in multi-modal underwater networks, transactions on wireless communications 17 (3) (2018) 1738-1754. [28] t. qiu, j. liu, w. si, d. o. wu, robustness optimization scheme with multi-population coevolution for scale-free wireless sensor. vol. 1, no. 1 | january june 2018 sjet | issn: 2616-7069 | vol. 1 | no. 1 | © 2018 sukkur iba 15 solar concentrator’s effect on solar panel efficiency manoj kumar panjwani1,2, li meicheng2, idris khan 2, zulfiqar ali2, mohan menghwar2, zulqarnain arain 1,2, danish khan2 abstract: given the current energy emergencies, the existing emphasis is increasing on the renewables as researchers predict near the end to fossils. in the light of the current renewable energy resources, the solar energy is seen to be one of the most reliable ones for the third world countries. moreover, the efficiency of current commercial photovoltaics hardly touches 30 %. this paper studies the mechanism of empowering solar concentrators to collect higher solar irradiation to concentrate on the solar panel and study the variations in the amount of power received and the temperature constraints. the study utilises the use of solar concentrators in regions under and over the mentioned standard temperature ranges by the manufacturer on the specification sheet, and thoroughly studies the variations observed in output parameters. keywords: solar concentrator; efficiency; temperature; renewable energy. 1. introduction the energy that is received directly from the sun is approximately near to 1413 w/ m2. however, the actual utilisation which is indicated on the ground scale is near to 1050 w/m2 as reported by the united states branch of agriculture, portland usa. in general, the earth’s top layer is nearly 30% more extreme than the one which is received on the ground. most studies report that the real solar energy that is being utilised for the normal operation of the solar panel is nearly 70% of the total energy that is received directly from the sun on planet earth. in other words, current photovoltaics utilises 70% of the energy received on the earth to satisfy our current energy demands [1-2]. 1 department of energy systems engineering, sukkur iba university pakistan 2 renewable energy school, north china electric power university, beijing china corresponding email: manoj.panjwani@iba-suk.edu.pk the manufacturers of the solar panel are always required to display a specification list on the back of the solar panel. the specification list consists of the various parameters that the solar panel is going to respond. most of the commercial solar panel manufacturers are reporting that their panels would respond to the standard when exposed to irradiations of 1000w/m2 and 25*c. in the case where the standard ranges are violated contribute to the irregular response from the solar panel, thus arising stability issues for the photovoltaic systems. more specifically, the solar panel is allowed to operate in areas which exceed the standard ranges of any parameter, which ultimately lead to increasing issues for the systems stability [3]. mailto:manoj.panjwani@iba-suk.edu.pk manoj kumar panjwani (et al.), solar concentrator’s effect on solar panel efficiency (pp. 15 27) sukkur iba journal of emerging technologies sjet | volume 1 no. 1 january – june 2018 © sukkur iba university 16 if considering areas in most south asian countries, the concern mostly raised by the manufacturer highlights the insights where there is an issue of increasing temperatures and most of the cities located in lower south asian regions touches 50*c+. given the current situation, the temperature ranges offered by the regions allowed most of the solar panels to deviate from the standard performance[3-4]. it is very important to know the temperature of the solar panel before we could design the system to respond to certain energy demand from the community. it is also important to highlight that the behaviour of the solar panel concerning environmental parameters is irregular. thus it allows the higher risk of instability issues for the systems which are off-grid and on-grid [5]. considering the polycrystalline solar panel, it indicates that when the temperature is decreased by one degree celsius above 25*c, the output power will also simultaneously affect. moreover, it indicates a standard range where it maintains its temperature coefficient. however, it also indicates that the temperature coefficient values also appear differently when the temperature ranges enter into ranges higher than the critical range for the solar panel [6]. with an increasing demand of utilising the solar concentrators in fulfilling the daily energy demands, the solar concentrators are also being utilised to allow a higher amount of solar irradiations to concentrate on a particular area and could lead to the higher amount of power output from the existing photovoltaic plant. it’s a matter of the fact that it’s the solar irradiations that ultimately are converted into power output in photovoltaic’s and not the heat. with empowering solar concentrators on concentrating the number of irradiations can help the system to operate in a certain range, and once the standard temperature is crossed, it appears to display negative impact on the overall output of the photovoltaic system. moreover, utilising the solar panel in ranges above the standard ultimately lead to an unreliable response of the panel on a longer run [7-8]. pearson correlation coefficient is mostly utilised to understand the linear behaviour/connection between any two variables. it can also be used to carefully understand the behaviour of the system if there is any change in a specific variable(s) [9]. during experimental analysis, solar trackers were utilised to assure that the concentrator could respond to the peak hours to assure maximum power conversion for the system. the system comprised a controlled laboratory environment where it was directed to bring expansion of the temperature with increasing amount of irradiation from a light source. in corresponding, the behaviour of the solar panel was carefully studied and reported. 2. experimental analysis experimental setup included a controlled test bench which included a 50w bp solar panel (polycrystalline) with specification vamp(17.3v),imp(2.9a),temperature coefficient of isc(0.065 ± 0.015)%/ °c, temperature coefficient of voc(-80 ±10) mv/°c and temperature coefficient of power(-0.5 ± 0.05)%/°c. it also includes hygrometer, thermometer, six tungsten filament bulbs acting as load (50,100,500,1000w), and 12 millimeters for point to point calculations. the readings were carefully monitored with every increase in humidity and temperature ranges. later the solar concentrator was employed to see the variations on the parameters affected. results were carefully monitored, and karachi,pakistan (latitude: 24.8934’, longitude: 67.0281’) was taken as a reference for experiments. 2.1. humidity’s effect on solar panel the values of voltage, current, and power continue to depreciate as there is an increase in the amount of humidity as can be referred from figure 1-3. linear depreciation range could be seen from humidity range 25-30% as can be referred from table 2. with an increase manoj kumar panjwani (et al.), solar concentrator’s effect on solar panel efficiency (pp. 15 27) sukkur iba journal of emerging technologies sjet | volume 1 no. 1 january – june 2018 © sukkur iba university 17 in the temperature in the room, the range of humidity was found decreasing. there was a decreasing trend which was followed by the voltages and currents when a variation was brought in the temperature. concerning figure 4, few parameters were getting disturbed when it comes to utilising the solar panels. a significant decrease in the voltage and humidity were noticed as there was a linear increase in the temperature ranges. figure 4 reflects the effect of temperature increase on the produced current. the current follows an unusual behaviour when there is a variation on the temperature. with an increasing level of humidity ranges, there is a decrement noticed on the number of voltages produced which also appears to cause various issues on the system’s stability and overall performance as can be referred from equation 1 [10]. the similar trend could be referred to the amount of current produced with the variation brought in the amount of humidity. thus the similar trend would also lead to increased stability issues for the system. the interesting fact noticed in the experiment shows that there is no constant trend followed by the current when there is variation brought on the system. with the current trend followed on the amount of power produced by the solar panel concerning variations brought from the variations in the humidity, various instability issues are ultimately leading to the unreliability of the photovoltaic systems as can be referred from table 1. 2.2. usage of solar concentrator solar concentrators are employed for various reasons including one for heating water and thermal energy production. moreover, they are currently employed to study their contribution to the increasing energy productions for the solar panel. solar concentrators could help in collecting higher intensities for the efficient energy conversion. the concentrators that were utilized in the experiment setup had a dimension of 850 x 565 x 50mm which was utilized to cover the area of a 50w solar panel. the side angle was kept 30 degrees for a reasonable tilt to encourage maximum power conversion. it can be easily noticed that with the increasing pattern of solar intensity over solar panel, there is a consequent increase in the amount of surface temperature on the solar panel. with increasing temperature, various issues can be associated with the temperature coefficient mentioned in the manufacturer’s specification list. ultimately, it starts deviating from the standard range, and hence there are stability issues that arise. moreover, the increasing temperature though somehow contribute positively as the amount of humidity that appears on the surface of solar panel starts decreasing making solar panel easy to convert the irradiations into electrical energy as can be referred from table 2. concerning the decreasing humidity because of the increasing temperature on the panel, despite the fact that humidity negatively affects the performance of solar panel, there is a decrease noticed in the current produced by the system. in result of a decrease in the amount of current from the system, various issues lead to unstable behaviour of the system as can be referred from table 3. due to continuous increment in the temperature ranges due to increase in the solar intensity, there is an irregular pattern followed by the power output. there are various reasons due to which it follows irregular behaviour, and most of them reflect the internal material characteristics of the material used in the manufacturing of the solar panel. the respective reading of irregular behaviour could be referred from table 4 and 5 and can be related from equation 2 and 3 [10]. from table 6, the pearson correlation value as stated in equation 4 is used for a default value under the range of parameters listed by the manufacturer. it can be seen that in the range of (6.85*c – 36.85*c), correlation of the photovoltaic power and solar radiation is greater than 0.85 which indirectly states that the solar radiation is the main factor that affects the output power from manoj kumar panjwani (et al.), solar concentrator’s effect on solar panel efficiency (pp. 15 27) sukkur iba journal of emerging technologies sjet | volume 1 no. 1 january – june 2018 © sukkur iba university 18 the solar panel. moreover, the temperature has a positive effect which means that the temperature increase in the region under the region specified can positively affect the power output of the panel. the results can also be verified referring the value of the power and the temperature in table 4. however, the humidity range can be seen portraying a negative value which states that the humidity negative impacts the overall power output from the solar panel. moreover, the value of the wind also has a little positive impact in a sense that the wind would provide the ventilation effect to the solar panel which varies from region to region. from table 7, the pearson correlation value is used for a default value over the range of parameters listed by the manufacturer. it can be seen that in the range of (36.85*c58.70*c), correlation of the photovoltaic power and solar radiation is greater than 0.85 which also validates the importance of the solar radiation in the overall power output of the panel. however, the interesting aspect of it lies in the temperature where the coefficient shows a negative value. the negative value shows that the temperature in a range higher than those indicated by the manufacturer has a negative impact on the power produced by the solar panel. the aspect could be seen validating the results obtained in table 5. the same aspect can be seen from the humidity’s part also that it also portrays a negative impact on the power produced by solar panel. however, wind factor could be seen positive so that the solar panel is exposed to need of ventilation for the said aspect. the results indicated after various attempts on the solar panel with variations from in the solar intensities from temperature range 6.85*c – 36.85*c shows a positive change in the output power output. however, once the temperature of 36.85*c is crossed, it starts portraying negative effect on the power output from the photovoltaic system. with an increasing trend from 36.85*c-56.70*c, the power output could be seen decreasing and arising many concerns over the stability of the installed photovoltaic system. 3. tables, figures, and equations 3.1. tables table 1. experimental values of voltage (v), current (a) and power (w) with increasing trend in humidity (%) on constant solar irradiance [9]. solar irradiance (w/ m2) temperat ure (c) humidity (%) voltage (v) current (amp) powers (watts) 800 31.85 40 17.1 2.41 41.21 800 31.85 45 16.89 2.34 39.52 800 31.85 50 16.75 2.21 37.08 800 31.85 55 16.54 2.14 35.39 800 31.85 60 16.45 2.02 33.22 800 31.85 65 16.35 1.92 31.39 800 31.85 70 16.32 1.84 30.02 manoj kumar panjwani (et al.), solar concentrator’s effect on solar panel efficiency (pp. 15 27) sukkur iba journal of emerging technologies sjet | volume 1 no. 1 january – june 2018 © sukkur iba university 19 table 2. solar irradiance calculated with and without concentrator with percent increase. solar irradiance (w/ m2) without concentrator solar irradiance (w/ m2) with concentrator percent increase 650 693 6.20 730 786 7.12 820 869 5.63 915 962 4.88 985 1037 5.01 1028 1086 5.34 1134 1197 5.26 table 3. power output calculated with solar concentrator. solar irradiance (w/ m2) humidity (%) temperature at the panel (c) voltage (v) current (amp) powers (watts) 650 25 31.85 16.3 2.12 34.56 730 25 32.35 16.9 2.24 37.86 820 25 32.85 17.1 2.31 39.50 915 24 33.15 17.11 2.37 40.55 985 23 33.85 17.14 2.42 41.48 1028 22 34.55 17.15 2.49 42.70 1134 21 35.33 17.15 2.51 43.04 table 4. calculated parameters with solar concentrator in the temperature range (6.85*c – 36.85*c). solar irradiance (w/ m2) concentrated irradiations(w/ m2) temperature at the panel (c) humidity (%) voltage (v) current (amp) powers (watts) 650 693 6.85 25 16.5 2.14 35.31 730 786 11.85 25 16.9 2.24 37.85 820 869 16.85 25 17.1 2.31 39.50 915 962 21.85 24 17.15 2.42 41.50 985 1037 26.85 23 17.16 2.48 42.55 1028 1086 31.85 22 17.16 2.52 43.24 1134 1197 36.85 21 17.18 2.61 44.83 manoj kumar panjwani (et al.), solar concentrator’s effect on solar panel efficiency (pp. 15 27) sukkur iba journal of emerging technologies sjet | volume 1 no. 1 january – june 2018 © sukkur iba university 20 table 5. calculated parameters with solar concentrator in the temperature range (26.85*c-58.70*c). solar irradiance (w/ m2) concentrated irradiations(w/m2) temperature at the panel (c) humidity (%) voltage (v) current (amp) powers (watts) 650 693 26.85 25 16.85 2.04 34.37 730 786 31.85 25 16.9 2.08 35.15 820 869 36.85 25 16.7 2.12 35.40 915 962 41.85 23 16.32 2.13 34.76 985 1037 46.85 21 15.37 2.14 32.89 1028 1086 51.85 19 14.8 2.16 31.97 1134 1197 58.70 16 14.25 2.19 31.21 table 6. pearson correlation coefficient for pv power with meteorological factors in the temperature range (6.85*c – 36.85*c). table 7. pearson correlation coefficient for pv power with meteorological factors in the temperature range (36.85*c-58.70*c). manoj kumar panjwani (et al.), solar concentrator’s effect on solar panel efficiency (pp. 15 27) sukkur iba journal of emerging technologies sjet | volume 1 no. 1 january – june 2018 © sukkur iba university 21 3.2. figures fig. 1. figure portrays the effect of humidity on voltage produced. fig. 2. figure portrays the effect of humidity on the current produced. fig. 3. figure portrays the effect of humidity on power produced. manoj kumar panjwani (et al.), solar concentrator’s effect on solar panel efficiency (pp. 15 27) sukkur iba journal of emerging technologies sjet | volume 1 no. 1 january – june 2018 © sukkur iba university 22 fig. 4. graph is portraying an increase in the solar intensity collected at the surface of the solar panel due to solar concentrator. fig. 5. the graph is portraying the effect of increase in the solar irradiations on panel’s power output, humidity and surface temperature. manoj kumar panjwani (et al.), solar concentrator’s effect on solar panel efficiency (pp. 15 27) sukkur iba journal of emerging technologies sjet | volume 1 no. 1 january – june 2018 © sukkur iba university 23 fig. 6. graph portraying the effect of an increase in the solar irradiations on panel’s power output, humidity and surface temperature in temperature ranges (6.85*c-36.85*c). fig. 7. graph portraying the effect of an increase in the solar irradiations on panel’s power output, humidity and surface temperature in temperature ranges (26.85*c-58.70*c). fig. 8. shows the solar concentrator used for the experimental analysis (850 x 565 x 50mm). manoj kumar panjwani (et al.), solar concentrator’s effect on solar panel efficiency (pp. 15 27) sukkur iba journal of emerging technologies sjet | volume 1 no. 1 january – june 2018 © sukkur iba university 24 fig. 9. design of the static solar concentrator mechanism utilizing the peak hours. fig. 10. portrays areas which are under high temperature because of the solar concentrator at 58.7*c. fig. 11. portrays areas at the backside of the solar panel at 58.7*c. manoj kumar panjwani (et al.), solar concentrator’s effect on solar panel efficiency (pp. 15 27) sukkur iba journal of emerging technologies sjet | volume 1 no. 1 january – june 2018 © sukkur iba university 25 3.3. equations voc module = temp coefficient ∗ (tstc t ambient) + voc rated (1) where: voc, mod = open circuit voltage at module temperature tstc [°c] = temperature at standard test conditions, 25 °c, 1000 w/m2 solar irradiance tambient [°c] = module temperature voc,rated = open circuit voltage at stc. (2) (3) , cov( , ) cov( , ) cov( , ) a b a b a a b b   (4) 4. results and discussions as per the results validated and investigated, it’s well understood that the photovoltaic systems appear to be working efficiently if there is solar concentrator’s used within the specified region mentioned by the manufacturer on the specification list. the solar concentrator is successful in collecting a significant amount of radiation to be converted. it can be referred from figure 4 and figure 5, that with an increase in the irradiations, there is a considerable increase in the temperature noticed and there is an irregular behaviour of the system noticed when the temperature ranges are brought to variant as specified on the specification list. it can be referred from figure 6 that when operating the solar panel from the range 6.85*c-36.85*c, the system is seen to deliver a higher amount of power output. however, referring to figure 7, when the specified range is surpassed, there appears decrement in the power output which indirectly makes the system more unstable and unreliable. the solar concentrator’s specification is specified in figure 8 which are incorporated in the experimental setup. from figure 9, it can be deduced that the solar concentrators can be incorporated to cover a specified angle to cover and utilize the peak hours for the photovoltaic system. referring figure 10, it can be observed that when the solar panel is exposed to solar concentrator, the centre of the solar panel is studied to have been exposed to increasing temperature which indirectly leads to irregular behaviour of the solar panel when the specified temperature range is surpassed. moreover, in the view of figure 10, the sides of the solar panel could be seen experiencing lesser temperature effect as compared to the centre part because of utilising the solar concentrators. moreover, referring figure 11, the impact of the solar concentrator could be seen at the back of the panel which is also experiencing a shift in the temperature ranges and is indicated by reddish colour. considering the facts mentioned above and figures utilising solar concentrator in ranges manoj kumar panjwani (et al.), solar concentrator’s effect on solar panel efficiency (pp. 15 27) sukkur iba journal of emerging technologies sjet | volume 1 no. 1 january – june 2018 © sukkur iba university 26 below mentioned could help in enhancing the power efficiency by utilising the solar concentrators. various experiments were conducted to validate the idea of increasing and decreasing of power output concerning solar radiations concentrated and allowed to hit the solar panel. 5. conclusion the thorough investigation was carried out to properly study and validate the idea of incorporating the solar concentrator on the solar panel to enhance the power efficiency. there is significant need to allow few changes to the photovoltaic system to allow a stable and reliable response. the proposed idea was seen working effectively in ranges identified as 6.85*c-36.85*c where in response to increasing solar intensity, the power output was seen increasing. however, the studied range from 36.85*c-58.70*c was seen negatively contributing to the power output and hence it was seen decreasing with increasing of solar intensity and surface temperature of the solar panel. therefore, predefined measures are to be considered before utilising the solar concentrators in areas that are hot and humid. 6. future recommendations given the irregular response of the solar panel with incorporating solar concentrator, heat sinks could help to control the overall temperature ranges of the solar panel. moreover, there could be additional ventilation factor that could be studied before incorporating the solar concentrators in areas under and above the standard range as specified by the specification list. additional ventilation could help effectively in increasing the overall stability and long-run durability of the photovoltaic system. additionally, there is a prompt need for self-cleaning of the solar panel that could also positively help in utilizing the proper conversion of the irradiation as there is a mixture of water and dust that forms a layer on the solar panel. however, there could be different solar panels that could be manufactured to be exposed to areas which are hot and humid. acknowledgment i would like to extend my thanking remarks to professor qi zheng from north china electric power university for the support and technical guidance. moreover, an earlier version of this paper was presented at the international conference on computing, mathematics and engineering technologies (icomet 2018) and was published in its proceedings available at ieee explorer. doi: 10.1109/icomet.2018.8346439. references [1] m. chegaar and p. mialhe, “effect of atmospheric parameters on the silicon solar cells performance” journal of electron devices, vol. 6, pp. 173-176, 2008. [2] r. gottschalk, d. g. infield, and m. j. kearney, “influence of environmental conditions on the outdoor performance of thin film devices,” in 17th european photovoltaic solar energy conference, 2001. [3] raghunathan, vijay, a. kansal, j. hsu, j. friedman, and m. srivastava, “design considerations for solar energy harvesting wireless embedded systems,” in proceedings of the 4th international symposium on information processing in sensor networks, pp. 64. ieee press, 2005. [4] zeller, peter, and h. m. libati, “utilization of solar energy for electrical power supply in rural african areas,” in africon 2009 (africon’09,) pp. 1-6. ieee. [5] ahmed, m. mohamud and m. sulaiman, “design and proper sizing of solar energy schemes for electricity production in malaysia,” in power engineering conference, 2003. pecon 2003, https://doi.org/10.1109/icomet.2018.8346439 manoj kumar panjwani (et al.), solar concentrator’s effect on solar panel efficiency (pp. 15 27) sukkur iba journal of emerging technologies sjet | volume 1 no. 1 january – june 2018 © sukkur iba university 27 proceedings. national, pp. 268-271. ieee, 2003. [6] omubo-pepple, v. b., c. israel-cookey, and g. i. alaminokuma, “effects of temperature, solar flux and relative humidity on the efficient conversion of solar energy to electricity,” european journal of scientific research, vol. 35, no. 2, pp. 173-180, 2009. [7] g. mostafa and f. khan, “an efficient method of the solar panel energy measurement system,” 1st international conference on the developments in renewable energy technology (icdret), 2009, pp. 1-3, ieee. [8] m. c. alonso-garcia, j. m. ruiz, and f. chenlo, “experimental study of mismatch and shading effects in the i–v characteristic of a photovoltaic module,” solar energy materials and solar cells vol. 90, no. 3, pp. 329-340, 2006. [9] karl pearson (20 june 1895), notes on regression and inheritance in the case of two parents. proceedings of the royal society of london, vol. 58, pp. 240–242. [10] m. k. panjwani, s. k. panjwani, f. h. mangi, d. khan, and l. meicheng, “humid free efficient solar panel,” in aip conference proceedings, vol. 1884, no. 1, p. 020002. aip publishing, 2017. format template vol. 6, no. 1 | january – june 2023 sjet | p-issn: 2616-7069 |e-issn: 2617-3115 | vol. 6 no. 1 january – june 2023 1 an energy management approach for isolated power system using low load diesel saira javed1, safdar raza1, mughees riaz1 abstract: renewable energy sources (res) are well known sources for providing energy in distant regions. this is the reason that hybrid isolated power system (hips) is utilized which integrates solar energy and wind energy. renewable energy (re) relies on the environmental conditions. the technologies such as batteries or diesel generator (dg) need to be employed to meet the load demand. battery energy storage system (bess) can diminish the limitation but this can add expense and intricacy to the system. dg is an excellent choice to meet load demand but it has certain limitations. due to diesel load set point, excess re generation is consumed via regulating devices such as dump load or bess. as a result, systems designed for high re penetration are now more complex, expensive, and wasteful. this study analyses low load diesel (lld). it is a method for minimizing surplus generation hence decreasing system intricacy. it also reduces fuel utilization without causing the control architecture to become overly complicated hence reducing the need for bess. it provides an alternate method for redefining diesel generation's low load capacity. this work provides an economic analysis of lld including comparisons to traditional bess applications. this analysis shows low operational cost of the system including lld than bess. hence demonstrating that bess can be replaced with lld. the use of lld also lowers fuel usage. a power system model of hips is simulated using matlab/simulink. keywords: renewable energy sources, hybrid isolated power system, diesel generator, battery energy storage system, low load diesel 1. introduction isolated power system (ips) cannot totally depend on widely accepted typical grid system as it is uneconomical across long distances [1]. in order to facilitate these areas with electricity, diesel generators are playing a vital role [2]. diesel generation has always provided readily available, dependable, and well-supported generating solutions [3]. unfortunately, it has certain drawbacks, one included is considerable operational costs. furthermore, diesel fuel may travel long 1 department of electrical engineering, nfc institute of engineering and technology, multan, pakistan. corresponding author: [safdar.raza@nfciet.edu.pk] distances which results in financial challenges. another disadvantage of diesel technology is the release of greenhouse gases [4][5]. relevant authorities have established objectives supporting the use of renewable energy sources (res) for generation of electricity in distant areas in an effort to minimize energy prices and pollution as they are environmentally safe and cost-effective alternatives to diesel [6]. the two most common res are wind and photovoltaic (pv), saira javed (et al). an energy management approach for isolated power system using low load diesel (pp. 1 10) sukkur iba journal of emerging technologies sjet | vol. 6 no. 1 january – june 2023 2 however both are stochastic in nature [7][8]. as a result, there is an imbalance between power supply and demand which causes reliability and stability concerns [9][10]. when there is high renewable energy (re) penetration, the diesel generator runs inefficiently while low load conditions, consuming more fuel causing greater damage to the engine. there is a variety of technologies and techniques available to assure system security; however, these techniques currently increase the system’s cost and complexity. the objective of any ips is to employ the smallest number of the techniques capable of balancing generation and power demand, permitting enough diesel capacity to maintain the supply and effectively utilizing existing renewable production to reduce operating expense [11]. multiple technologies, including as dump load, battery and flywheel, are provided to improve the renewable penetration. the energy storage system (ess) is one method to enhance flexibility and control in an ips [12]. unfortunately, because of the premature battery degradation, using a vast battery-based ess is now too costly [13]. flywheel storage technique is often less expensive than battery energy storage systems (bess), but it has mechanical restrictions that energy can be exchanged only for a short period of time (seconds) [14]. as a result, flywheel use is restricted, and it is most frequently linked with fast-start diesel engines. balancing of state of charge (soc) of bess as a means for maximum use of combined power and energy capacity has been recommended [15][16]. these techniques lower the battery's maximum depth of discharge, therefore extending its lifetime. dump load technique is used to spill surplus energy. energy spillage that occurs as a result is irrecoverable, decreasing efficiency of the system and lowering re use. demand side management (dsm) is also a viable and practical method for assisting system functioning while also reducing energy consumption [17][18]. it is also utilized in ips to improve re output and provides the system more flexibility [19]. but it is a complex system and requires highly skilled staff. a further way to increase power quality is to use droop controllers to control wind and solar production in the same way that conventional power stations do [20]. the dynamic droop scheme proposed in [19] retains the benefits of traditional droop control methods while also providing flexibility and effectiveness during fluctuating res. maximum power point tracking (mppt) is a technique used in pv systems to optimize the output power of solar arrays regardless of temperature, irradiance, or electrical characteristics of load [21]. although these techniques have a beneficial impact on grid qualities but it causes increased re spilling and reduces the economic productivity. many different ips projects are available to demonstrate an effective control strategy for high acceptance of re. different techniques are investigated in three case studies on australia's king island, flinders island, and rottnest island. first technique outlines integration of wind and storage. flinders island describes about integrating pv, wind and storage. the third technique outlines a mechanism for integrating pv, wind and without the need of storage. all options allow for significant re penetration, with each island receiving the bulk of its energy from re sources. the first technique demonstrates king island being one of the high re penetration ips. the second technique considers the advantages of re diversity. the third technique focuses at how low load diesel (lld) and dsm technologies may be used to rationalize energy storage. the third approach observed a 32% cut in capital costs, establishing the economic reasons for the approach by suspending integration of the energy storage [19]. diesel technology should not be entirely eliminated in isolated communities. diesel fuel efficiency may be enhanced without compromising power quality or stability by aiming to reduce the amount of energy produced by the fuel. using lld methods, saira javed (et al). an energy management approach for isolated power system using low load diesel (pp. 1 10) sukkur iba journal of emerging technologies sjet | vol. 6 no. 1 january – june 2023 3 this technique may be maximized. lld methods minimizes the reliance on fossil fuels in the system, resulting in greater adoption of re and reduced power costs. from the above literature it is observed that ess is one solution to enhance system efficiency, however it is costly. diesel generator (dg) is an excellent choice but still there is a need to manage fuel consumption. the main objectives of this paper are to minimize operational cost and use of fossil fuel of the system and to accept high re. the following is the structure of this paper; section 2 describes the modelling of the system. model verification with different control techniques is discussed in section 3. results and discussions are presented in section 4. section 5 is concluding the paper. 2. modelling of the system solar energy system comprises pv array, dc-dc boost converter, an mppt controller and dc-ac converter as displayed in fig. 1. in solar system the mppt technique maintains the pv voltage close to mpp voltage. the mppt technique either operates in on mode or off mode, it depends on the soc of bess. vpv is the voltage from photovoltaic array while vdc is the voltage from dc-dc converter. fig. 1. solar energy system wind energy system contains wind turbine, doubly fed induction generator (dfig), ac to dc converter, a power converter and a dc to ac converter as displayed in the fig. 2. in fig. 2, wm is the rotor speed whereas θ is the pitch angle of the turbine blade. the wind turbine's received power can be defined by the following formula [22]. 𝑃 = 1 2 𝜌𝐴𝑉𝑤 3 𝐶𝑝𝑜𝑤 (λ, 𝜃) (1) where p is the mechanical power of the turbine, ρ is the density of the air which is approximately 1.225kg/m3, a is the swept area of turbine blade, 𝑉𝑤 3 is the wind speed and cpow is the coefficient of turbine power. cpow depends on λ – tip speed ratio and θ – turbine blade pitch angle. the pitch control serves to alter the power captured by adjusting the angle of attack of the blades by rotating them in their longitudinal axis. dfig makes use of a variable-speed wind turbine. the minimal maintenance and operational costs of a dfig makes it a good choice. wind speed affects the generator output. a power converter is used to raise the voltage level. fig. 2. wind energy system the bess comprises lead-acid battery and a bidirectional dc-dc buck boost converter which is in charge of maintaining the dc bus voltage using a controller as displayed in fig. 3. the battery has two modes of operation: charging and discharging. it depends upon power produced by res. the bidirectional converter couples res and bess. by means of a bidirectional converter, power may flow in both ways, from load to bess and vice versa. when the available res are enough to generate the desired power for load, power flows from res to bess and bess charges. the bidirectional converter will be operating in buck mode. when the supplies of res are insufficient to fulfill the load demand, power flows from bess to load and bess discharges. at this moment, the bidirectional converter is operating in boost mode. the battery runs in these two modes as well, dependent on the energy limitations specified by the soc limits [23]. saira javed (et al). an energy management approach for isolated power system using low load diesel (pp. 1 10) sukkur iba journal of emerging technologies sjet | vol. 6 no. 1 january – june 2023 4 socmax ≥ soc ≥ socmin (2) the allowable limit of soc of battery is described in (2). socmax shows the battery's maximum permitted soc. it denotes the maximum charge level or threshold over which the battery is not recommended to be charged anymore. excessive charging can result in overcharging, that can lower battery lifespan, or even cause safety issues. socmin indicates the battery's lowest allowable soc. it is the lower limit or threshold under which the battery is prohibited from being discharged significantly. soc indicates the battery's current soc. it represents the real amount of energy stored in the battery at any particular time. fig. 3. battery energy storage system during periods of excess re absorption, a diesel engine operates at low load in hybrid isolated power system (hips). at certain situations, the operator has two options: keep a constant diesel output while spilling extra re, or reduce diesel output while absorbing more re [24]. lld technology is the capability to run diesel generator below conventional load limits in order to accept greater re input. by eliminating the engine's low load constraint of ~30-40% of rated capacity, lld permits the engine's full capability to be used. the lesser the diesel output, the more load may be shifted to re sources. lld does not require any new hardware, as it uses current diesel components and does not require any changes to the mechanical or electronic design. as a result, the lld has a model that is identical to a conventional diesel engine [22]. it only differs in terms of engine characteristics that have to be adjusted, particularly by reducing temperature and pressure of cylinder. it is the effect of a complex combination of lower combustion efficiency, decreased ring orientation between the cylinder and the piston, lower turbo spool velocity as well as significantly lower air charge boost pressures. all of this leads to low engine efficiency when the load is lower. lld technology can be simulated by modifying engine specific delay (τ1). utilizing the watson method to forecast τ1, the value must be 0.3-0.5ms greater for lld as compared to conventional generators [24]. fig. 4. conventional diesel engine the dump load is a regulated resistive load. it is used to convert electricity into heat depending on the governor actuator signal as shown in fig. 4. tm is the mechanical torque whereas diesel engine is denoted by k1 which is the steady state gain and is multiplied by e-sτ1. dump load facilitates the integration of re and increases security of the system. there are three different dispatchable factors which are taken into consideration for the hips scenario: lld, bess, and the dump load. in this case, operational costs are calculated according to the following formulas [22]. clld = alld + blld plld + clld plld 2 (3) cbess = abess + bbess(pbess +3pbess.max(1-soc)) + cbess (pbess + 3pbess.max(1-soc)) 2 (4) cdl = rele pdl (5) where clld, cbess and cdl are the cost functions for lld, bess and dump load respectively. plld, pbess and pdl represents the power levels for lld, bess and dump load respectively. the maximum power level for bess is represented by pbess.max. saira javed (et al). an energy management approach for isolated power system using low load diesel (pp. 1 10) sukkur iba journal of emerging technologies sjet | vol. 6 no. 1 january – june 2023 5 soc indicates the state of charge of storage system. the utility's rate for electricity is referred to as rele. alld, blld and clld are cost coefficients for lld while abess, bbess and cbess are cost coefficients for bess. their values are given in table ι. table ι. cost coefficients sources a b c lld 30 4e-8 6e-11 bess 20 5e-5 8e-11 3. model verification the suggested hips consists of average load of 2 mw and contains lld, solar arrays, wind turbines, bess and dump load. matlab is used to model the suggested hips structure, and several situations were observed. 3.1. control technique including bess the first case illustrates the control strategy by modelling hips containing solar energy, wind energy, bess and dump load. the framework design and energy stream for the proposed solar, wind framework with bess is displayed in fig. 5. the metrics for hips including bess are given in table ⅱ. fig. 5. hybrid isolated power system including bess table ⅱ. metrics of hybrid isolated power system including bess peak load (mw) 2 average load (mw) 1.5 solar pv capacity (mw) 2.3 wind capacity (mw) 1.3 bess capacity (mw) 1.5 dump load capacity (mw) 1.5 the framework can be simply controlled as there is just a single dispatchable power source which is the bess. when the net load which is the difference between the actual load and the re output is negative, implying that power provided by the re is adequate to serve the load, the abundance energy is then used to charge the bess and any further excesses are dumped. whenever the net load is positive, the bess discharges energy to fulfill the load. the operating plan of this sort of framework is displayed in fig. 6. fig. 6. hybrid isolated power system including bess dispatch algorithm 3.2. control technique including lld the second case illustrates the control strategy by modelling hips containing solar energy, wind energy, lld and dump load as shown in fig. 7. the metrics for hips including lld are given in table ⅲ. saira javed (et al). an energy management approach for isolated power system using low load diesel (pp. 1 10) sukkur iba journal of emerging technologies sjet | vol. 6 no. 1 january – june 2023 6 fig. 7. hybrid isolated power system including lld table ⅲ. metrics of hybrid isolated power system including lld peak load (mw) 2 average load (mw) 1.5 solar pv capacity (mw) 2.3 wind capacity (mw) 1.3 diesel capacity (mw) 2 dump load capacity (mw) 1.5 generally, diesel engine companies defined a minimum typical working load for their engines, often 30% of rated capacity [25]. as a result, load thresholds limit the maximum re contribution within an ips. unlike these conventional diesel generators, lld are able to operate under 30% threshold load for longer amount of time. lld will dump energy peaks and respond fast at all times, by low loading the engines a very high amount of re penetration can be achieved. the dump load controls the power balance during periods of surplus energy and assist lld during fast load variations. a magnetic clutch is fitted between the diesel engine and alternator. the pre-heater system maintains an optimal temperature of the engine during low load operation. the cooling fan is operated separately from the engine. the pre-pressure system ensures pressure in the combustion air receiver during low load operation. when re is not available lld provides power like any conventional diesel generator. re is now increasing, the lld decreasing load and controls voltage, frequency and power balance. when the lld drives under the 30% load threshold, the pre-pressure and the pre-heater system becomes active. this is the beginning of low load operation. re continues to increase and load on lld continues to decrease controlling voltage, frequency and power balance. when there is excess of re penetration, it starts to deviate frequency. to control frequency, surplus re is dumped. when the dumped amount of re becomes stable, the engine cutches out and stops. the spinning alternator does not stop and connected to the bus bar it always provides reactive power. when re is decreasing, the diesel engine starts, it starts fast as it is already warmed, pre-pressurized and is disconnected from the alternator. it then clutches in to add load. this adaptation takes only a few seconds. lld operates in high fuel savings in a smooth operation and without the use of bess. the operating plan of hips including lld is displayed in fig. 8. fig. 8. hybrid isolated power system including lld dispatch algorithm saira javed (et al). an energy management approach for isolated power system using low load diesel (pp. 1 10) sukkur iba journal of emerging technologies sjet | vol. 6 no. 1 january – june 2023 7 4. results and discussions to validate the efficacy of proposed lld, two cases are simulated in matlab. one is hips including bess, the other is hips including lld and their metrics are given in table ⅱ and table ⅲ respectively. in (fig. 9), nondispatchable variables which are solar power, wind power and power demand are displayed. these variables are same in both the control techniques. 4.1. hips including bess the battery runs in discharging mode from 18:00 to 05:00, supplying power and meeting electricity demand along wind energy. the technique makes use of the battery's stored energy as well as the steady availability of wind power during the night. as a result, the battery drains its stored energy while the wind turbines continue to generate electricity, delivering a constant and consistent power supply during this time. the scenario shifts from 05:00 until 18:00. solar energy and wind energy are principally in charge of meeting electricity demand during these daytime hours. the pv panels capture and convert sunlight into energy, while the wind turbines continue producing power. these res work together to supply the energy demands. during this period, the battery changes to charging mode. the excess power generated by the pv panels and wind turbines above the present need is stored in the battery for use later on. surplus energy may be stored and used during periods of higher demand or lower re generation by charging the battery during the daytime when the generation of electricity is normally higher. the process of discharging the battery and using wind energy at night, and charging the battery while using solar and wind energy during the day, results in an effective power supply system. it optimizes energy storage, maximizes the utilization of res, and assures an uninterrupted supply of electricity throughout the day, efficiently balancing energy output and demand. 4.2. hips including lld the simulation results of control technique including lld are shown in (fig. 11). lld is aiming to minimize the operational cost. it offers considerable economic advantages to hips by offering extra 30% of engine capacity in favor of lowering operational expenses. more re penetration is the indirect result of this strategy. there is a considerable penetration of re in the system between 06:00 and 17:00. as a result, the lld generator runs at low load. when the re penetration exceeds the power demand, the excess power is routed to a dump load. this controlled disposal of surplus power assists to ensure system stability, preventing possible instabilities caused by an excess of energy. the system enables stable and balanced operation during periods of high re penetration by properly managing extra power via the dump load. from 17:00 to 05:00, both wind energy and the lld generator work together to deliver electricity to fulfil demand. during this period, wind energy provides a large share of power generation, while the lld generator complements the supply as needed. this cooperative operation assures a constant and stable energy supply throughout the night by using available wind resources and optimizing the utilization of the lld generator. overall, using lld in the hips system reduces costs, stimulates increased re penetration, and keeps the system stable. the system maximizes the benefits of res while assuring a dependable and cost-effective operation by effectively managing power generation and utilization. by using (3)(4) the operational costs of bess and lld are analyzed for over 24 hours and the results are given in table ⅳ. saira javed (et al). an energy management approach for isolated power system using low load diesel (pp. 1 10) sukkur iba journal of emerging technologies sjet | vol. 6 no. 1 january – june 2023 8 table ⅳ. comparison of control techniques over one day system operational cost in $/mwh including bess 485.88 including lld 330 fig. 9. non-dispatchable variables fig. 10. hybrid isolated power system including bess saira javed (et al). an energy management approach for isolated power system using low load diesel (pp. 1 10) sukkur iba journal of emerging technologies sjet | vol. 6 no. 1 january – june 2023 9 5. conclusion an energy management approach for ips is discussed in this paper. two cases are modelled using matlab. first case comprises solar arrays, wind turbines, dump load and bess. in this case, it is demonstrated that high re can be captured by utilizing bess but unfortunately it has high operational cost which has been measured to be 485.88 $/mwh. the second case includes solar arrays, wind turbines, dump load and lld. it is demonstrated that bess can be replaced with lld because of its low operational cost recorded 330$/mwh. the development of ips is costly by following conventional system designs as it causes high operational costs. the use of lld lowers fuel usage while eliminating the necessity for bess inside the system. lld is distinct between many existing technologies because it may serve both low and high re penetration ips without adding to the expense, complexities, or threat to system stability. references [1] w. jing, c. h. lai, w. s. h. wong, and m. l. d. wong, “a comprehensive study of batterysupercapacitor hybrid energy storage system for standalone pv power system in rural electrification,” appl. energy, vol. 224, no. january, pp. 340–356, 2018. [2] d. akinyele, j. belikov, and y. levron, “challenges of microgrids in remote communities: a steep model application,” energies, vol. 11, no. 2, pp. 1–35, 2018. [3] s. k. tiwari, b. singh, and p. k. goel, “control of wind-diesel hybrid system with bess for optimal operation,” ieee trans. ind. appl., vol. 55, no. 2, pp. 1863–1872, 2019. [4] a. hirsch, y. parag, and j. guerrero, “microgrids: a review of technologies, key drivers, and outstanding issues,” renew. sustain. energy rev., vol. 90, pp. 402–411, jul. 2018. [5] m. alves, r. segurado, and m. costa, “on the road to 100% renewable energy systems in isolated islands,” energy, vol. 198, p. 117321, may 2020. [6] v. v. v. s. n. murty and a. kumar, “optimal energy management and techno-economic analysis in microgrid with hybrid renewable energy sources,” j. mod. power syst. clean energy, vol. 8, no. 5, pp. 929–940, 2020. [7] p. dhabai and n. tiwari, “effect of stochastic nature and location change of wind and solar generation on transmission lattice power fig. 11. hybrid isolated power system including lld saira javed (et al). an energy management approach for isolated power system using low load diesel (pp. 1 10) sukkur iba journal of emerging technologies sjet | vol. 6 no. 1 january – june 2023 10 flows,” 2020 int. conf. emerg. technol. incet 2020, pp. 1–5, 2020. [8] t. g. hlalele, r. m. naidoo, r. c. bansal, and j. zhang, “multi-objective stochastic economic dispatch with maximal renewable penetration under renewable obligation,” appl. energy, vol. 270, no. november 2019, p. 115120, 2020. [9] g. notton et al., “intermittent and stochastic character of renewable energy sources: consequences, cost of intermittence and benefit of forecasting,” renew. sustain. energy rev., vol. 87, no. august 2017, pp. 96– 105, 2018. [10] s. member, “grid integration challenges and solution strategies for solar pv systems : a review,” ieee access, vol. 10, pp. 52233– 52257, 2022. [11] a. m. eltamaly, m. a. alotaibi, a. i. alolah, and m. a. ahmed, “a novel demand response strategy for sizing of hybrid energy system with smart grid concepts,” ieee access, vol. 9, pp. 20277–20294, 2021. [12] y. liu, w. du, l. xiao, h. wang, and s. bu, “sizing energy storage based on a life-cycle saving dispatch strategy to support frequency stability of an isolated system with wind farms,” ieee access, vol. 7, pp. 166329–166336, 2019. [13] m. u. jan, a. xin, h. u. rehman, m. a. abdelbaky, s. iqbal, and m. aurangzeb, “frequency regulation of an isolated microgrid with electric vehicles and energy storage system integration using adaptive and model predictive controllers,” ieee access, vol. 9, pp. 14958–14970, 2021. [14] a. saleh, a. awad, and w. ghanem, “modeling, control, and simulation of a new topology of flywheel energy storage systems in microgrids,” ieee access, vol. 7, pp. 160363–160376, 2019. [15] n. ghanbari and s. bhattacharya, “soc balancing of different energy storage systems in dc microgrids using modified droop control,” proc. iecon 2018 44th annu. conf. ieee ind. electron. soc., vol. 1, pp. 6094–6099, 2018. [16] s. chowdhury, m. n. b. shaheed and y. sozer, ‘state-of-charge balancing control for modular battery system with output dc bus regulation,’ in ieee transactions on transportation electrification, vol. 7, no. 4, pp. 2181-2193, dec. 2021. [17] z. li, y. xu, x. feng, and q. wu, “optimal stochastic deployment of heterogeneous energy storage in a residential multienergy microgrid with demand-side management,” ieee trans. ind. informatics, vol. 17, no. 2, pp. 991–1004, 2021. [18] b. n. alhasnawi and b. h. jasim, “a new internet of things enabled trust distributed demand side management system,” sustain. energy technol. assessments, vol. 46, no. may, p. 101272, 2021. [19] j. hamilton, m. negnevitsky, x. wang, and s. lyden, “high penetration renewable generation within australian isolated and remote power systems,” energy, vol. 168, pp. 684–692, 2019. [20] n. m. dawoud, t. f. megahed, and s. s. kaddah, “enhancing the performance of multi-microgrid with high penetration of renewable energy using modified droop control,” electr. power syst. res., vol. 201, no. february, p. 107538, 2021. [21] r. ahmad, a. f. murtaza, and h. a. sher, “power tracking techniques for efficient operation of photovoltaic array in solar applications – a review,” renew. sustain. energy rev., vol. 101, no. october 2018, pp. 82–102, 2019. [22] e. semshchikov, m. negnevitssemshchikov, e., negnevitsky, m., hamilton, j., & wang, x. (2020). cost-efficient strategy for high renewable energy penetration in isolated power systems. ieee transactions on power systems, 35(5), 3719–3728, j. hamilton, and x. wang, “cost-efficient strategy for high renewable energy penetration in isolated power systems,” ieee trans. power syst., vol. 35, no. 5, pp. 3719–3728, 2020. [23] c. jamroen, s. sirisukprasert, and n. hatti, “a study on soc management of energy storage system for voltage regulation application in distribution network,” 11th int. renew. energy congr. irec 2020, vol. 5, 2020. [24] j. hamilton, m. negnevitsky, x. wang, and e. semshchikov, “the role of low-load diesel in improved renewable hosting capacity within isolated power systems,” energies, vol. 13, no. 15, 2020. [25] e. semshchikov, j. hamilton, l. wu, m. negnevitsky, x. wang, and s. lyden, “frequency control within high renewable penetration hybrid systems adopting low load diesel methodologies,” energy procedia, vol. 160, no. 2018, pp. 483–490, 2019. format template vol. 1, no. 1 | january june 2018 sjet | issn: 2616-7069 | vol. 1 | no. 1 | © 2018 sukkur iba 34 a comparative analysis of different commercial lights shoaib ahmed shaikh1, hamza ali1, mansaf ali abro1, m talha iqrar1, abdul manan memon1 abstract: there is a huge amount of financial losses due to usage of inefficient appliances in domestic, commercial and industrial sectors. a common appliance which occurs in the domestic, industrial and commercial loads is the lighting. this paper represents the study of different types of lights used in shopping malls by focusing on the different parameters of lights as lumens, efficiency, power consumption, temperature. a survey was conducted in the shopping mall and measurements were also taken which shows the negative impact on the economic, power sector and environment. the proposed system was initiated by using the other types of lights with the help of dialux software which shows the improved results of cost, lumens, temperature, power consumption and environmental benefits. keywords: lighting overview; lighting comparision; shopping mall survey; environmental impacts; power quality scenario. 1. introduction there are different types of loads used in the buildings as; inductive, capacitive and resistive. lighting system consists of different lights which again comprises in the abovementioned load categories. this most common system keeps vital role and is crucial for ensuring its product, safety and luxury of the residents in the buildings. however, proper designing of the lighting is necessary for getting the desired requirement of output of illumination with least quantity of electricity use. from the report the artificial lighting consumption is up to 20-30% of the total commercial loads electricity consumption in a building [1]. as per guidance of iea the lighting consumption from global electricity consumption is 1 fest, hamdard university karachi, pakistan corresponding email: skshaikh@outlook.com distributed in percentage form as depicted in the pie chart in figure 1[2]. fig. 1. global electricity consumption of light [2]. mailto:skshaikh@outlook.com shoaib ahmed shaikh (et al.), a comparative analysis of different commercial lights (pp. 34 44) sukkur iba journal of emerging technologies sjet | volume 1 no. 1 january – june 2018 © sukkur iba university 35 there is a huge gap in developing countries between demand and supply, surveys is being conducted and measures are being taken to reduce the consumptions of electricity as their demand side (dm) management part. it is estimated that by switching energy efficient technologies the reduction of energy up to 27% in residential side and 30% in commercial side could be received [3]. this has increased the usage of power electronic or non-linear energy saving devices. by extensive usage of these electronic equipment’s, negative harmful impacts on the quality of power in the distribution system may arise. with extravagance one problem's solution will generate several other technical problems. experiments and measurements have proved and clarified that preventation is more profitable and economical after the fact being known, rather than initiative of other problem's solution findings [4]. so many techniques occur to reduce the power consumption limit. among these techniques replacement of inefficient energy lamps with the other efficient lamps is one of the best techniques. replacing the incandescent lights with standard energy efficient lights is economical in the summer season by the reduction of cooling needs in the building as well as reducing the lightning power consumption [5]. surveys, studies and measures have proved that there is a significant portion of lighting constitution in the country’s total electricity consumption. in accordance with the swedish energy agency report, around 23 % of the country's total consumption of electricity occurs for lighting [6]. there is a momentous quantity of lighting consumption of the total energy resources in the world. in accordance with 2011 statistics, there are about 7.2% of lightning consumption of the developed and advanced world's primary energy assets which is accountable for the huge amount i.e. 430x10^9kg of carbon emission [7]. with such a huge amount of co2 emission and energy use, increasing the lightning efficiency by taking surveys and measurements is mandatory [8-9]. electricity rational consumption in buildings has become very essential and pertinent subject, particularly when growth of energy is becoming costlier and climate change may be initiated due to immoderate use through high release of greenhouse (co2) gases [10]. energy consumption growth and emission of greenhouse (co2) gases in urban surroundings have made policies for energy saving and improving efficiency a prime concern in the energy plans of almost all countries [11]. particularly in building, energy utilization for lightning is an extensive contributor to co2 release, and its estimation has been taken which accounts for 20 to 40% of total energy utilization in buildings [12-13]. this paper represents the comparison of lights used in a shopping mall with its performance characteristics as power consumption, its temperature, lumens, efficacy, etc., environmental impacts due to lighting usage and some other power quality issues. we have designed a wooden box on a dialux software to check all the mentioned parameters with the help of instruments as watt meter, lux meter and infra-red thermometer. 2. overview of lights there are various types of lights used as indoor and outdoor applications. at a recent time, the opinion of utilizing the more eminent and enduring light emitting diode (led) in the applications which were consistently the province of inefficient and short life compact fluorescent lamps (cfls) and incandescent lamps (ils) has given the result of the development of led lights. relatively, shoaib ahmed shaikh (et al.), a comparative analysis of different commercial lights (pp. 34 44) sukkur iba journal of emerging technologies sjet | volume 1 no. 1 january – june 2018 © sukkur iba university 36 in the general lightening system, led technology is new and is developing continuously which have made it exigent for assessing its environmental aspects. led lamps primarily are planned for domestic and commercial consumers. moreover, led lamps are environmentally affable as compared to other lamps like cfl has mercury inside it [14]. each appliance has their own pros and cons. despite this, it is necessary to use the standardized and efficient appliances as lights. in the selection of lights, the following important factors are considered shown in figure 2. fig. 2. factors for the selection of lights. following are some types of lights which are familiar and mostly used for domestic and commercial purpose: 2.1. incandescent lamp: this is a common household light bulb. it’s simple yet brilliant. it was invented in late 1800s and amazingly it has hardly changed at all. in early it had on the top priority and in high usage due to lack of other lights inventions. heat is the main drawback of incandescent lamp and considered as highly inefficacious light bulb because loss of input energy is about 90% as heat output [15]. the efficacy range of il is 1020lumen/watt, which depends on their construction features and temperature of the filament during operation [16]. generally, the rated life period of il is less (<) around 1000hrs as compared to other lamps [17-18]. halogen gas keeps vital role in incandescent lighting, special by adding this gas in incandescent lamp glass that has made the lifetime range higher. according to the us market report 2010, higher consumption (62%) of ils has lowered the value of efficiency i.e. 19.1lumen/watt in the residential sector. this value could be improved by replacing the inefficient il with other durable and energy efficient lights [19]. researchers and experts tried to increase efficiency of il and they asserted that the efficacy of hl may be increased to a value 45lumen/watt, but verification has not been achieved [20]. in european union countries, due to above so many cons, eu commission had emphasized for the installation of il to be banned from sep 2012 on priority basis. it was not a proper solution to ban the product rather to give the alternate solution of making it an efficient. as this issue could be resolved by the usage of inert gases having emptiness co2 emissions or other harmful gases which increased the cost due to high consumption. it is also estimated that electrical energy consumption in houses can be reduced up to 10-15% [21]. 2.2. fluorescent lamp: the common type of discharge lamp is a fluorescent lamp (fl) or tube used today in many sectors. this type of light is further classified as cfl and lfl. inside a cfl or ifl, a uv light is produced due to passing of electrical charge through mercury gas. this light then results in the excitement of coated phosphorescent on the inner side of the tube for the production of the light. in fluorescent lighting, ballast is required for supplying an amount of current to start up. this can be attached on lighting fitting and shoaib ahmed shaikh (et al.), a comparative analysis of different commercial lights (pp. 34 44) sukkur iba journal of emerging technologies sjet | volume 1 no. 1 january – june 2018 © sukkur iba university 37 can be integrated in the bulb's design. a fluorescent is a more efficient lamp as an incandescent lamp at present has been eliminated due to inefficiency and other drawbacks. typically, the lamp's surpassing initial cost is neutralized by smaller energy cost [22]. many shapes and sizes occur for fluorescent lamps. the fluorescent lamps (fls) are recognized by their standard coding system which specifies the parameters and operating typical features with their relevant information. 't' is a key factor which denotes tabular and shows the diameter of tube, e.g. 1inch diameter itemizes t8 tube [23]. due to less power consumption and more luminous, cfls is accredited as costeffective "energy saving lamps" as compared to il [24]. equivalence of cfl and il can be done with the ratio 4:1; this means that for the same light 80w il could be replaced by 20w cfl [25]. 2.3. led lamp: a new type of device for lighting spreads over the planet the led. it isn’t a new device some way or another it has been used for years all around the world. what is new however, is being achieved greater power emission than a few years ago and making it provide white light. their advantage that it consumes less energy (<) as the traditional incandescent lamps (il) uses high energy. a traditional lamp i.e. il needs to be heated to emit light and a lot of energy is emitted and wasted in the heat form. moreover, the materials suffer this heating problem at high temperature values. recently, several types of energysaving lamps have become popular. the first energy saving lamps that replaced incandescent ones is fluorescents, which contain gases inside. on the other hand, leds can be made very small and solid elements are used in leds. in addition, leds are familiar due to their easily control, allow new applications such as generation of any light spectrum visibility of demand, optimizing energy costs and information transmission, this is known to be smart lighting. a more efficacious, long lived led lamp is also an environmentally friendly lamp than other light sources due to the empty mercury composition material. today the high power white led has increased luminous efficacy value reached up to 231lumen/watt in a laboratory [26]. from the measures being taken and tests being conducted in the lab, it is shown that in domestic led light and cfls will not initiate any harmonic problem in the future of the network as compared to classic light bulbs [27-28]. 3. methodology we have taken the measurands and counting of various lights used in shopping mall. the shopping mall consists of basement, ground floor and other four floors. there are so many shops in a shopping mall as shown in figure 3. fig. 3. different shops in a shopping mall. the most common lights used in a shopping mall are fl. cfl, il, halogen, hqi-ts, hpi-t, hpi-ts and hci-t for different locations. as above mentioned that the lights performance can be observed by checking its parameters as; power rating, temperature, lumen etc. the existed data of lumen of different portions and shops of shoaib ahmed shaikh (et al.), a comparative analysis of different commercial lights (pp. 34 44) sukkur iba journal of emerging technologies sjet | volume 1 no. 1 january – june 2018 © sukkur iba university 38 building is given in the form of bar charts in figure 4, figure 5 and figure 6 respectively. fig. 4. lumens data of the shopping mall. fig. 5. lumens data of shops in a mall. fig. 6. existed power rating of the lights (53767 or 53.767kw). we have checked the data of lighting used in a mall. now we are going to select the other lights which are recommended as efficient and cost-effective lights. a wooden box is set which is designed by using the dialux software to check the results of exiting lights and recommended lights as shown in figure 7. our focus is to check the lumens, temperature and power rating by using the instruments as lux meter, infra-red thermometer and wattmeter. for experiments, we take three existed lights and three recommended lights to check their performance in a designed box as shown in figure 8. the rating of existed lights is given as: a1 = fl = 36w, 56lumens, 37°c b1 = cfl = 24w, 50lumens, 38°c c1 = halogen = 50w, 270lumens, 60.5°c the rating of recommended lights is given as: a2 = fl = 16w, 60.8lumens, 32°c b2 = cfl= 11.7w, 65.2lumens, 34.5°c c2 = halogen = 7.8w, 470lumens, 35.3°c shoaib ahmed shaikh (et al.), a comparative analysis of different commercial lights (pp. 34 44) sukkur iba journal of emerging technologies sjet | volume 1 no. 1 january – june 2018 © sukkur iba university 39 fig. 7. box selection on dialux software. fig. 8. lights comparison. after replacing the lights, we got the power rating result in the form bar chart as shown in figure 9, which clearly shows the improved results. it is an obvious that there is a direct relationship of power consumption with power rating and operating time. so, a positive result of the graph also depicts the recommended lights are cost-beneficial, high lumens value and low temperature rating. fig. 9. recommended power rating of lights. the next comparison is of the lumens and temperature mentioned in the charts given below in figure 10 and figure 11 respectively. fig. 10. lumens of different lights. shoaib ahmed shaikh (et al.), a comparative analysis of different commercial lights (pp. 34 44) sukkur iba journal of emerging technologies sjet | volume 1 no. 1 january – june 2018 © sukkur iba university 40 fig. 11. temperature of different lights. 4. energy and enviromnetal impacts: a greenhouse gas is not a particular gas, but consists of other different gases. greenhouse gases in an atmosphere trap heat and keep the planet warmer. human beings, their activities and liveliness are the responsibility for all of the growth in greenhouse gas emission from the last 150years.the primary greenhouse emission sources in united states (us) are electricity, transportation, industry, commerci al/residential, agriculture and land use for forestry. in figure 12, total us greenhouse gas emission by economic sector 2015 are presented in percentage form according to the us environment protection agency [29]. fig. 12. us greenhouse gas emission by economic sector 2015. total emission in 2015 was equal to 6,587 million metric tons of co2 equivalent. the greenhouse (gh) gases comprise of co2, n2o,ch4 & fluorinated gases. a pie chart of the total emission is given in figure 13. fig. 13. greenhouse gases emission. the energy we utilize in our homes, mainly dependent on the atmosphere where we live and the different type devices that consume energy which are in our usage. figure 14 shows the pie chart of residential energy consumption in percentage for the year 2009 [30]. https://www.epa.gov/ghgemissions/sources-greenhouse-gas-emissions#colorbox-hidden shoaib ahmed shaikh (et al.), a comparative analysis of different commercial lights (pp. 34 44) sukkur iba journal of emerging technologies sjet | volume 1 no. 1 january – june 2018 © sukkur iba university 41 fig. 14. residential energy consumption survey (recs) 2009. it is not widely considered and focused that the biggest and main reason of greenhouse gas emission is lighting. the energy consumed to supply lighting necessitates greenhouse gas emission of 19x102 megatons of co2/year throughout the world [31]. as each of us are producing co2 gas from our daily activities as by turning the lights and it is already discussed above that lightning is one of the main sources of producing co2 gas. we can reduce the co2 emission gases with the usage of advanced lighting technology. light bulbs are not associated with carbon dioxide but when we switch on the lights in our homes, this deadly co2 gas in initiated in the generation of electricity on which those light bulbs powers. changing our incandescent light bulbs or other types to new, more efficient and high environmental friendly led lamp is the best for an ease reduction of carbon emissions. vitae energy consulting claims in his recent report that saving could be £1.4 billion a year on its energy spend industry in the uk and 10 million tons (mts) of co2 emissions annually by updating and modernizing the lighting stock on the usage of today’s energyefficient and advanced lighting technologies. the study and survey was carried over 500 companies in the warehousing and manufacturing sector and concluded that, a quarter of the companies in around surveyed and observed, the lighting system accelerated in the 1950s and consumed almost inefficient light bulbs that were sheltered in fittings not ameliorated for efficient light radiation. the study also showed that energy usage of industrial lighting energy could be cut relatively 60% if the fittings were optimized for using the specially designed reflectors for increasing the overall light. 5. power quality scenario incandescent light has unity power factor as it is a purely resistive load type lamp. the main advantage of this lamp is that it does not need any electronic driver to start thus no any harmonic issue occurs. whereas other lamp types such as led lamps and discharge lamps require special drivers for the operation purpose, hence produces harmonic distortions in the supply current wave which disturbs the sinusoidal waveform [32-33]. inductance in ballast in case of discharge lamps has low lagging power factor which disturbs the power triangle, so it is necessary to compensate. a capacitor for compensation is the best solution to be connected in parallel with blast to increase the value the power factor (p.f) in a florescent lamp. in new t5 fluorescent lamp (fl) luminaire, there is improved p.f of a good value 0.9 and improved thd value (<15%) due to usage of electronic ballast [33]. whereas cfl of low rating with electronic ballasts have low leading power factor (0.5-0.6). due to weight and space issues, low rating cfls cannot be compensated individually [34]. thus, power factor can be improved centrally in a given location if low rated cfls with large quantity are used [35]. led lamps designed as a source of voltage with a low rating of series resistance to limit the line current il, have usually much higher power factor than other shoaib ahmed shaikh (et al.), a comparative analysis of different commercial lights (pp. 34 44) sukkur iba journal of emerging technologies sjet | volume 1 no. 1 january – june 2018 © sukkur iba university 42 lamps (discharge lamps). according to the united states dept. of the energy star program, the acceptable range of power factor (p.f) 0.70.9 has been mandated for domestic and commercial light emitting diode lamps [36], also uk energy saving trust has mandated a minimum acceptable power factor (p.f) of 0.7 with a prolonged objective having power factor of 0.9 for integral light emitting diode lamps [34]. 6. conclusion a common load which is always on peak usage in each season is of lighting. it is very important to select the proper lights for domestic, commercial and industrial usage. this paper focus on the profile of all types of lights specifically fl, cfl, il and halogen. a survey of a shopping mall was being conducted for different types of light on different locations. there were lot of impacts due to existed lights as lumens, efficacy, temperature, power losses etc. then other types of light with different parameters were recommended by selecting a wood box with a usage of dialux software which showed the improved results in this research work. this is not only important for the performance of lights but very much cost beneficial from economic point of view. on the other hand, it is also seen from consumption and environmental point of view that the il lamp has the co2 emissions issues and high energy consumption. halogen lamp was better than il due to inert gases existed inside it which are not so worse than il lamp. fl and cfl lamp was much better than il lamp and halogen due to low consumption of energy and environmental friendly. furthermore, the above lights can also be replaced with the new technology of lights as “led” which have led all types of lights due to several advantages. our next task is to work on the led lights and on the cons of above lights to give the improved techniques. acknowledgment this is the most difficult part of the paper to give rewarding words to others on their life or work. first and the foremost, we give thanks to almighty allah who gave us the inner strength, resource and ability to complete our comprehensive research successfully, without which all our efforts would have been in vain. than we acknowledge the support and constant encouragement of hamdard institute of engineering and technology, hamdard university, karachi, throughout the completion of this research. last but not the least we wish to express our sincere thanks to all our friends for their goodwill and constructive ideas. references [1] jc. lam, dhw. li, and s. cheung, “an analysis of electricity end-use in airconditioned office buildings in hong kong,” building environ, vol. 38, no. 3, pp. pp. 493–8, 2003. [2] energy conservation in buildings and community systems program (ecbcs) annex 45 guidebook on energyefficient electric lightingfor buildings, edited by liisa halonen, eino tetri & pramod bhusal, international energy agency, 2010. [3] j. trifunovic, j. mikulovic, z. djurisic, m. djuric, and m. kostic, “reductions in electricity consumption and power demand in case of the mass use of compact fluorescent lamps,” energy vol. 34, pp. 1355–1363, 2009. [4] n. r. watson, t. l. scott, s. hirsch, “implications for distribution networks of high penetration of compact fluorescent lamps,” ieee transactions on power delivery, vol. 24, pp. 1521– 1528, 2009. [5] r. saidur, “energy consumption, energy savings, and emission analysis in shoaib ahmed shaikh (et al.), a comparative analysis of different commercial lights (pp. 34 44) sukkur iba journal of emerging technologies sjet | volume 1 no. 1 january – june 2018 © sukkur iba university 43 malaysian office buildings,” energy policy vol. 37, pp. 4104–4113, 2009. [6] m. bladh and h. krantz, “towards a bright future? household use of electric light: a microlevel study,” energy policy, vol. 36, pp. 3521–3530, 2008. [7] k. powell, “panel4: lessons from the field. solid-state lighting program: u.s. department of energy,” 2011. available from:/http://apps1.eere.energy.gov/b uildings/publications/pdfs/ssl/powell_l essons_sslmiw2011.pdfs (access on:3 august 2012). [8] j. r.-m. belizza, s. –p. claudia, “electricity sector reforms in four latinamerican countries and their impact on carbon dioxide emissions and renewable energy,” energy policy vol. 38, pp. 6755–6766, 2010. [9] sheinbaum, c., rui´z, b.j., ozawa, l., 2011.energy consumption and related co2 emissions in five latin american countries: changes from 1990 to 2006 and perspectives. energy, vol. 36, 3629– 3638. [10] linhart f, scartezzini j-l. minimizing lighting power density in office rooms equipped with anidolic daylighting systems. solar energy 2010; 84(4):587– 95. [11] pérez-lombard l. a review on buildings energy consumption information. energy build 2008; 40:394– 8. [12] energy information administration. commercial buildings energy consumption survey; 2003 [13] brunner, e.j., ford, p.s., mcnulty, m.a., thayer, m.a., 2010. compact fluorescent lighting and residential natural gas consumption: testing for interactive effects. energy policy 38, 1288–1296. [14] beth daley, “mercury leaks found as new bulbs break: energy benefits of fluorescents may outweigh risk,” the boston globe, february 26, 2008 [15] brunner, e.j., ford, p.s., mcnulty, m.a., thayer, m.a., 2010. compact fluorescent lighting and residential natural gas consumption: testing for interactive effects. energy policy 38, 1288–1296. [16] doe, 2012a. 2010 u.s. lighting market characterization. solid-state lighting program:u.s. department of energy. available from: /http://apps1.eere.energy.gov/building s/publications/pdfs/ssl/2010-lmc-finaljan-2012.pdfs(access on:1august2012). [17] osram, 2009. life cycle assessment of illuminants a comparison of light bulbs, compact fluorescent lamps and led lamps. [18] simpson, r.s., 2008. lighting control— technology and applications. focal press. [19] doe, 2012a. 2010 u.s. lighting market characterization. solid-state lighting program:u.s. department of energy.available from: /http://apps1.eere.energy.gov/building s/publications/pdfs/ssl/2010-lmc-finaljan2012.pdfs(accesson: 1august2012). [20] eceee, 2011. evaluating the potential of halogen technologies. european council for an energy efficient economy.available from: /http://www.eceee.org/ eco_design/products/directional_lighti ng/halogen_technologies_report/ eceee_report_halogen_technologiess (access on:27 july 2012). [21] europa, 2009. phasing out conventional incandescent bulbs (faq-press release). available from: /http://europa.eu/rapid/pressreleasesact ion.do?reference= memo/09/368s (access on:20 september2012). [22] onaygil s, güler ö. determination of the energy saving by daylight shoaib ahmed shaikh (et al.), a comparative analysis of different commercial lights (pp. 34 44) sukkur iba journal of emerging technologies sjet | volume 1 no. 1 january – june 2018 © sukkur iba university 44 responsive lighting control systems with an example from istanbul. building and environment 2003; 38(7):973–7. [23] roisin b, bodart m, deneyer a, d’herdt p. lighting energy savings in offices using different control systems and their real consumption. energy and buildings 2008;40(4):514–23 [24] simpson, r.s., 2008.lighting control— technology and applications. focal press. [25] vito, 2007. eco-design study lot 19domestic lighting. preparatory studies for eco-design requirements of eups. available from: /http://www.eup4light. [26] cree: cree 231 lumen per watt led shatters led efficacy records. [online]. available: http://www. cree.com/press/press_detail.asp? i=1304945651119. [accessed november 17, 2011]. [27] s.k. ronnberg, m.h.j. bollen, et. a! harmonic emission before and after changing to led and cfl part i: laboratory measurements for a domestic customer, 14th international conference on harmonics and quality of power, p. 1-7,2010. [28] s.k. ronnberg, m. wahlberg, et. a! harmonic emission before and after changing to led and cfl part ii: field measurements for a hotel, 14th international conference on harmonics and quality of power, p. 59-67, 2010. [29] https://www.epa.gov/ghgemissions/in ventory-us-greenhouse-gas-emissionsand-sinks [30] https://www.eia.gov [31] key world energy statistics 2007 (international energy agency, paris, france, 2007). [32] philips, 2009. the abc’s of electronic fluorescent ballasts: a guide to fluorescent ballasts. available from: /http://www.advance.philips.com/doc uments/uploads/ literature/rt-8010r03_abc.pdfs (accesson:3 august2012). [33] akashi, y.,2002.t5 fluorescent systems. the lighting research center, national lighting product information program(nlpip). available from: /http://www.lrc.rpi.edu/programs/nlp ip/publicationdetails.asp?id=284&type =2s (access on: 5august2012). [34] cie, 2012. led bulb placement meeting new challenges. components in electronics. available from: /http://content.yudu.com/a1wimc/ciea pril12/resources/52.htms (accesson:5 august2012). [35] sehat sutardja, 2009. green opportunities. marvell semiconductor,inc. available from: /http://www.marvell.com/environment /assets/marvell-green-opportu nities.pdfs (access on:20july2012). [36] ecn magazine, 2011. power factor correction techniques inled lighting. available from: /http://www.ecnmag.com/products/201 1/08/power-factor-correctiontechniques-led-lightings (access on:22 september2012). https://www.epa.gov/ghgemissions/inventory-us-greenhouse-gas-emissions-and-sinks https://www.epa.gov/ghgemissions/inventory-us-greenhouse-gas-emissions-and-sinks https://www.epa.gov/ghgemissions/inventory-us-greenhouse-gas-emissions-and-sinks https://www.eia.gov/ format template vol. 6, no. 1 | january – june 2023 sjet | p-issn: 2616-7069 |e-issn: 2617-3115 | vol. 6 no. 1 january – june 2023 11 power quality improvement and harmonics compensation using hybrid filter arslan arshad1, rohail asghar1,muhammad arsalan ilyas2, muhammad mudassar2*, zubair khalid2 abstract: the need for electricity is expanding at an even faster rate in these modern times. in order for the electrical devices to function properly and effectively, a constant supply of high-quality power is required. the most common types of power quality reducing factors include noise, interruptions, variations in voltage and frequency, and so on. these factors all contribute to a decrease in the electrical devices' overall efficiency. total harmonic distortion (thd) was made worse by the presence of non-linear loads. the existence of harmonics is the primary cause of the problems that lead to the breakdown of insulation, excess heating, and a shortened lifespan for various pieces of equipment. in addition to this, if there is a high thd in the electrical system, it may cause the energy meter to give inaccurate readings. an economic hybrid filter can be employed to reduce the losses caused by harmonics distortion, thereby providing a solution to those issues. this paper provides an in-depth look into the application of this filter for harmonic compensation. by performing simulations with the simulink tool of matlab and validating the results using the experimental setup, it has been determined that using a filter can reduce the total harmonic distortion (thd) of the current by 40.09 percentage points, which will result in better power quality and energy conservation. the ieee standard 519-1992 was consulted as a reference when making this determination. keywords: power quality, harmonics, hybrid filters, total harmonic distortion, simulink 1. introduction electricity is the most popular energy form and its supply is heavily required by the modern society. it is hard to imagine a life without electricity supply. in the same way the electric power quality which is being supplied is also very necessary for the better performance of the consumer equipment’s or devices. in the power sector, the power quality 1 centre for energy research and development, university of engineering & technology, lahore, pakistan 2 department of technology, the university of lahore, lahore, pakistan corresponding author: mudasser_90@hotmail.com is the most important term and it concerns vastly to the users and electric power company [1]. the power quality which is being supplied to the users rely on the power ranges of frequency and voltage. if the frequency and voltage of the power supply are changed from those of the standard ones, the quality of the energy is disturbed or impaired. at present, the advancement of semi-conductor devices is a arslan arshad (et al.), power quality improvement and harmonics compensation using hybrid filter (pp. 11 22) sukkur iba journal of emerging technologies sjet | vol. 6 no. 1 january – june 2023 12 matter of days for technology development. by this advantages and development, semiconductor devices have a permanent place in the energy industry to facilitate the overall control of the system. furthermore, most of the load is also semiconductor built equipment. however, semiconductor devices are characterized by non-linear and drag non-linear current from the source. semi-conductor devices are also engaged in the conversion of electricity from ac to dc or vice versa [2]. this power transition has many switching operations that can introduce interruption in the current. because of this interruption and nonlinearity, the generation of harmonics disturbs the quality of electricity which is supplied to the end user. modern sources of harmonics include all nonlinear loads such as power electronic equipment including adjustable speed drives asds, switched mode power supplies, and data processing equipment. harmonics and reactive power are the root causes of a number of issues, including the distortion of the supply voltage, the excessive heating of transformers, a power factor that is too low, an excessive current, the failure of the control system, the loss of insulation, and the destruction of electronic devices. because of this, each and every one of these problems presents a significant challenge for the electrical system. therefore, the reduction of risk is extremely important for both the customer service and the customers. the presence of harmonics is the primary factor that contributes to the aforementioned issues, and filtering out harmonics is the approach that should be taken to address these concerns [3]. therefore, harmonics compensation is absolutely necessary in order to maintain the high quality of the electric power. recently, the loads mostly used in industry or commercially cause the harmonics generation. the current harmonics disturb the voltage of system which gradually upsets the performance of system and provides unwanted circumstances like insulation failure, control system failure, electrical and mechanical fluctuations in the alternator, overheating problems and unpredictable protection behavior etc. these above all the mentioned problems are serious for the electrical system, so harmonic mitigation is essential for the consumers and utility purposes [4]. the purpose of this paper is to discuss ways in which the persistent risk of system losses that is associated with harmonics in line currents can be mitigated. the primary goal is to minimize the amount of power that is wasted by operating the shunt active power filter at a very low switching frequency. on the other hand, this contributes to an increase in the total harmonic distortion. this can be accomplished through the utilization of a hybrid filter, which is a cost-effective strategy that combines active and passive filter arrangements. when compared to the shunt active filter, which accomplishes the same goals at a higher switching frequency, this method yields sinusoidal source current with unity power factor at a lower switching frequency. this allows to obtain these results at a lower cost. as a consequence of this, the strength of the active filter is diminished, and the drawbacks of the passive filter are alleviated. there are two distinct parts to this method that can be utilized. the electrical quality is improved thanks to the elimination of low-order harmonics by the apf and the elimination of higher-order harmonics by the passive filter. the overall cost is brought down without any corresponding loss in efficiency. 2. power quality and harmonics power systems are intended to work at a frequency of 50 or 60 hz. nevertheless, particular kinds of non-uniform loads generate current and voltages among frequencies which are whole number multiple of the essential frequency. these frequency mechanisms famous as harmonic contamination and is possessing contrary outcome on the power scheme grid [5]. this is usually a customer arslan arshad (et al.), power quality improvement and harmonics compensation using hybrid filter (pp. 11 22) sukkur iba journal of emerging technologies sjet | vol. 6 no. 1 january – june 2023 13 determined problem. so, power attribute delinquent is expressed as “any amount of established in current, voltage or frequency deviations that effect in harm, distressed, loss or broken of end user appliances.” 2.1. power quality issues energy efficiency is influenced by any disparity in current, voltage or frequency. common problems that affect the instrument's variability are power system faults, variation in frequency, power surges, improper grounding affect, blackouts or brownouts, transients and electrical line noise. the effects of these problems are the harmonics production. harmonics reduced power quality and could damage the end user devices. these harmonics causes insulating failure, underground cable heating, increase losses and reduce the equipment’s life etc. 2.2. harmonics creation pure sinusoidal waveforms can be found in true waveforms of phase or line currents and voltages. this indicates that it is made up of a fundamental frequency of exactly 50 hz in its purest form (as is the case in pakistan). nevertheless, the actual waveform is made up of numerous sine waves operating at a variety of frequencies, with one operating at the power frequency and being referred to as the fundamental component. the other frequencies that are not quite as dominant are referred to as the harmonics [6]. the value of a specific frequency that is compounded of the basic frequency is known as the harmonic component, also referred to simply as the harmonic. the magnitude of the harmonic component is greatest at frequencies that are close to the fundamental frequency, and it begins to decrease as higher orders of the fundamental are achieved. in a normal alternating system, voltage varies by sinusoidal at a certain frequency typically 50 or 60 hz. when a connected load to the system is linear, it pulls a current which is sinusoidal in nature and has same frequency such as voltage. when a connected load to the system is non-linear in nature like a rectifier then drag current is also non-sinusoidal. the resulting waveform of current is complicated which depends on load type. the equipment’s used in offices like printers, fax machines, personal computers and rotating machines in industry are other examples of nonlinear loads [7]. i. static converters: these devices are made up of thyristors and gate firing apparatus. a number of different parameters, including as asymmetry, inaccuracy in thyristor firing times, switching timings, and inadequate filtering, all contribute to the modification of the amplitudes of the distinctive harmonics. in the case of thyristor bridges, one might also notice a shift in the harmonics as a function of the thyristor phase angle. ii. lighting: lighting systems that use discharge lamps or fluorescent lamps can generate harmonic currents. these types of lamps are used in fluorescent lighting. in some circumstances involving contemporary compact fluorescent lighting, a third harmonic ratio can possibly go above one hundred percent. the neutral conductor therefore carries the sum of the third harmonic currents of the three phases, and as a result, if it is not suitably sized, it may be subjected to dangerous overheating. 3. effects of linear and non linear loads in the past, the vast majority of loads were linear, which means that when they were connected to a sinusoidal voltage, these devices would produce a sinusoidal current. when connected to a sinusoidal voltage, the majority of loads in use today behave in a nonlinear manner (for example, power electronics such as rectifiers, frequency converters, switched mode power supplies, electronic lamps, and so on). this means that these devices produce non-sinusoidal currents, as depicted in fig. 1. these currents are made up not only of the basic current but also of currents of higher frequencies, which skew the sinusoidal waveform in an undesirable way. arslan arshad (et al.), power quality improvement and harmonics compensation using hybrid filter (pp. 11 22) sukkur iba journal of emerging technologies sjet | vol. 6 no. 1 january – june 2023 14 current harmonics are the primary factor in the generation of voltage harmonics [8]. unless the non-linear load is also pumping power, it will not directly cause voltage harmonics to occur on its own. the system shows the waveforms of two different loads. one is non-linear and other one is linear. as we can observe that non-linear load current is not smooth. in fact, this wave has a great deal of harmonic contents. on the other hand, the linear load current waveform is far smoother and consists of the fundamental frequency component only [9]. figure 1: comparison of linear and nonlinear loads in time domain total harmonic distortion, more commonly known as thd, is a standard measurement of a signal. it is defined as the ratio of the total of all harmonics components to the value at the fundamental frequency. the thd for the current can be found in the case of the power system in the equation 1 thdi = iharmonic ifundamental × 100% (1) the above equation can be expand in given form, thdi = √∑ ij 2∞ j=2 i1 = √i2 2+i3 2+i4 2…….in 2 i1 (2) where in is the root mean square rms value of the nth harmonic and j=1 is fundamental frequency. therefore, the thd can be decrease by increasing ifundamental or by decreasing iharmonic. 4. effects of harmonics on power quality when a load that is not uniform is connected, a sinusoidal source will produce a distorted current in the circuit. harmonics are present in the current that has been distorted. a voltage droplet for each separately harmonic current forms whenever that current's harmonic passes through the supply impedance. the amount of voltage twisting is affected by the current as well as the impedance of the supply. harmonics cause disruptions in the quality of the electric power. harmonics can have unfavorable effects on quality, including but not limited to the following: computer system failures, hasty motor exhaustions, buzzing in telecommunication cable lines, and warmness of transformers [10]. these are just a few examples of the kinds of problems that quality drawbacks can carry into household and engineering industry. a relatively minor problem with quality might prevent the entire industry from functioning normally. noise is a chief problem associated with the harmonics. capacitors are seen to overheat with the production of harmonics. the current increase in the system is one of the major issues of power scheme harmonics. this is the predominant opportunity for third harmonic that causes strong growth in the current of zero order, thereby raising the current fluctuations in neutral. 5. harmonics filteration techniques there are many problems that disturb electrical systems like transients, noise and voltage sag etc. these problems resulting in harmonic production and affecting the power quality supplied to the end user. harmonic frequencies may occur in waveforms of voltage or current those are multiple members of the fundamental frequency which do not contribute to the supply of active power. for this purpose filters are utilized at pcc in which load is associated to the power supply. the performance of system is increased by using that filters. filters are used to overcome the problems produced by harmonics. for this, various filter techniques are available in the arslan arshad (et al.), power quality improvement and harmonics compensation using hybrid filter (pp. 11 22) sukkur iba journal of emerging technologies sjet | vol. 6 no. 1 january – june 2023 15 literature. passive filters are used initially, but they are highly relying on parameters of system. in addition, the system encryption is suitable for filtering a particular sequence of events. thus, in order to address the drawbacks of passive filters the use of active filters is necessary [11]. various types of filters are available for this objective. the complete sketch is shown in the given fig. 2. 5.1. pasive filters harmonic currents can be mitigated with the help of passive filters, which are made up of a collection of passive elements such as resistors, capacitors, and inductors that are tuned to a particular frequency. there have been no addition of any active components, such as operational amplifiers, at any point. the harmonic current is redirected to ground by the passive filters, which also generate a path with low impedance for the particular harmonic frequency. figure 2: classification of filters therefore, passive filters enhance the voltage and current of the supply system without the adverse effects that are caused by the harmonics produced by non-linear loads. a resistor, an inductor, and a capacitor are the three components that make up the single tuned passive filter. by creating a path with low impedance, the inductor and the capacitor are intended to reduce the impact of a particular order of frequency. in comparison to the design of an active filter, the construction of a passive filter is extremely straightforward and cost-effective [11]. formulas have been provided, and those will serve as the basis for the filter parameters that will be designed for the proposed work. reactive power (kvar) = kva*sin (cos1(pf)) filter reactance xfil = kv2 (1000) kvar ω (3) capacitive reactance xcap = xfil ∗ h 2 h2 − 1 ω (4) inductive reactance xl = xcap h2 ω (5) harmonic frequency fh = 1 2 π√lc (6) where h is harmonic order, l is inductance and c is capacitance. the passive filters have some drawbacks which are given below:  due to occurrence of passive elements, these filters are massive and too heavy. these filters restrained the harmonics which are usually low order.  oscillation or reconciliation problem that affects the stability of the power system's network.  filter features are influenced by the frequency deviation in the energy system and tolerances in components cannot be realized in an environment with varying frequency.  the filter is loaded when the size of the harmonics in the ac lines rises.  the impedance of the power supply disrupts the compensation functions of lc filters. arslan arshad (et al.), power quality improvement and harmonics compensation using hybrid filter (pp. 11 22) sukkur iba journal of emerging technologies sjet | vol. 6 no. 1 january – june 2023 16 5.2. active power filters in recent years, due to advancements in switch technology, the study of active power filters has become an increasingly popular research topic. when dealing with high levels of power, the cost of magnetic and capacitive components can become prohibitively expensive. recent years have seen the development of high frequency switching devices with high current and voltage ratings. some examples of these devices include the metal oxide semiconductor field effect transistor (mosfet) and the insulated gate bipolar transistor (igbt). these are primarily made up of power electronic switching devices like thyristors and igbts, both of which are incredibly fast and have a large switching capacity respectively. these filters perform their primary function during run time by sensing the variations in load currents at each point in time and injecting signals to cancel out the effects of harmonics if they are present [12]. in the design of active filters, current or voltage pulse width modulation inverters make up the active filter. these are preferred over the conventional passive filter due to the fact that these have the capacity to overcome the disadvantages associated with the passive filter. this is the primary reason for their widespread use. however, it is important to note that passive filters have limitations. they are designed for fixed reactive power compensation at specific tuning frequencies, making them unsuitable for variable load applications. the variation in load impedance can affect the tuning of the filters, potentially reducing their effectiveness. despite this drawback, the simulation results demonstrate that the passive filters perform satisfactorily in meeting the reactive power demand [13]. high-parameter active filters provide stability to the power system. by having sufficient capacity to compensate for the harmonic currents, they prevent voltage distortions, improve power factor, and maintain system stability. this is particularly crucial in sensitive applications where stable and highquality power is essential. designing active filters with high parameters allows for future expansion and modifications to the power system. it provides the flexibility to handle increased loads or changes in the harmonic profile without the need for immediate upgrades or replacements. this helps in future-proofing the power system against potential changes or growth [14]. it is important to note that the selection of active filter parameters should be based on a thorough analysis of the power system, including harmonic content, load characteristics, and system requirements. professional engineering expertise and proper sizing calculations are necessary to ensure that the active filter parameters are appropriately determined for optimal performance and costeffectiveness [15]. active compensations currently have the ability to overcome the drawbacks that are associated with passive filters. additionally, the power factor of the power systems improves thanks to the active power filter's contribution. both in its steady state and in its transient state, it demonstrates excellent compensation properties. in comparison to passive filters, the initial investment and ongoing expenses associated with these filters are significant. nevertheless, when used by themselves, active filters run into the following issues: it is difficult to construct a large rated current source with a rapid current response. the control system is complex, and its performance against high frequency harmonics is ineffective. the initial cost and the ongoing cost are both high. this shortcoming was remedied by the development of a novel strategy known as a "hybrid filter," which is a combination of a passive filter and an active filter. 5.3. hybrid filters the hybrid filter is a combination of active and passive filters in a single device. this configuration is effective because it takes arslan arshad (et al.), power quality improvement and harmonics compensation using hybrid filter (pp. 11 22) sukkur iba journal of emerging technologies sjet | vol. 6 no. 1 january – june 2023 17 advantage of everything that both filters have to offer. new and improved characteristics of passive filters can protect against the damage caused by shunt and series resonances. therefore, hybrid filter topologies can use the benefits of both passive and active power filters, which include the ease of use and lower cost effectiveness of passive filters, as well as the higher performance of active filters. they are solutions that can control current variations and distortions while also compensating for harmonics at a low cost as simulation is performed to validate it in fig. 3. additionally, they can control current variations. these filters eliminate the issues that were caused by the use of both filters. therefore, the primary goal of hybrid apf is to improve the filtering performance of highorder harmonics while also providing a costeffective mitigation of low-order harmonics. because of this, both work together to produce a much more pure sinusoidal waveform in the line currents that they generate. it is important to point out that the topology of the passive and active filters in hybrid filters can take either the form of a series or a parallel configuration, as appropriate. 6. simulation the simulink model of a hybrid filter for the electrical power quality is composed of a power factor correction (pfc) filter, an active filter, an energy storage device such as an electrolytic capacitor, an inductor and a switch mode power supply (smps). the pfc filter eliminates current harmonics while the active filter eliminates voltage harmonics. the switch mode power supply provides a pulsed dc voltage and current. the inductor acts as a buffer and the capacitor helps in stabilizing the output voltage. the control system for the smps is responsible for controlling the switching of the mosfet switches and hence controlling the output voltage. the analysis revealed that substantial harmonic currents still reached the mains supply even after the introduction of an lcfigure 3: hybrid filter block diagram in simulink arslan arshad (et al.), power quality improvement and harmonics compensation using hybrid filter (pp. 11 22) sukkur iba journal of emerging technologies sjet | vol. 6 no. 1 january – june 2023 18 passive filter. fig. 4 depicts the sinusoidal wave of source current, whose frequency spectrum analysis displays minimal harmonic components. this suggests that hybrid power filters are effective in the elimination of harmonics from non-linear loads as shown in fig. 5. 7. hardware setup the experimental setup used for the mitigation of current source harmonics is shown in figure 6. this hardware setup of the hybrid active filter for harmonics mitigation involves the combination of a passive filter and an active filter with system parameters shown in table. 1. the passive filter is used to reduce the harmonic current levels, while the active filter is used to reduce the harmonic voltage levels. the active filter is composed of a single-phase voltage source inverter (vsi) and a dc capacitor. the vsi is used to inject a compensating current into the system to reduce the harmonic voltage levels. the dc capacitor is used to store the energy generated by the vsi and to provide a stable dc voltage source for the vsi. the hybrid active filter is connected to the point of common coupling (pcc) of the system, and it is controlled by a microcontroller. the microcontroller is used for monitoring the system, calculating the compensating current and controlling the vsi. figure 4: fft analysis before filtration figure 5: fft analysis after filtration arslan arshad (et al.), power quality improvement and harmonics compensation using hybrid filter (pp. 11 22) sukkur iba journal of emerging technologies sjet | vol. 6 no. 1 january – june 2023 19 table i system parameters parameters values source voltage 400 v frequency (f) 50 hz load resistance rl 0.1k ω load capacitance cl 100mf tuned passive filter cf5=50µf, lf5=8.1mh cf7=20µf, lf7=8.27mh cf11=20µf, lf11=8.27mh filter coupling inductance 2.5 mh active filter parameter cd=1500µf, laf=10mh dc capacitor cdc=3.5µf sampling time 0.2 µs figure 3: hardware implementation 8. results & discussion the examination of the results exhibited that the present waveforms were a long way from the sinusoidal waveform, because of the harmonic currents that were added to the power supply system by the non-linear burden. at the point when the filtration circuit was employed, the resulting waveforms was figure 4: thd value without filter improved, and distortion effect was decreased by utilization of the recommended filter scheme as seen in fig 5. figure 5: thd value after filtration 8.1. digital storage oscilloscope results the hardware setup is tested in the power electronics lab of university of engineering and technology uet. figure 9 shows the output waveform without filter circuitry, harmonic distortion can be visualized in the display of digital oscilloscope. figure 6: waveform without using filter figure 7: waveform after filtration arslan arshad (et al.), power quality improvement and harmonics compensation using hybrid filter (pp. 11 22) sukkur iba journal of emerging technologies sjet | vol. 6 no. 1 january – june 2023 20 the key component of our discussion is the power ratings of the mosfet which must be utilized for the active power filter; it must be incredibly high and this necessity has caused us to design the hybrid active power filter. the results acquired from using the hybrid active power filter are shown here for you to look at. once more, it is evidently clear that the amount of harmonic current in this situation is not of significance. nevertheless, mosfets are typically low-noise and low-distortion, so they can be used effectively to generate very low harmonics. however, the overall performance of the filter will depend on the design of the circuit, so it is important to consider the filter's design parameters when considering harmonics that may be generated. the thd value recorded from the hardware set-up was 46.8% prior to filtration. when the filtration circuit was active, this decreased to 35.8%. this was due to the fact that the components used were less efficient and inexpensive and so the software and hardware results did not match. this shows that this hardware set-up is a basic version and not the most efficient. if more standardized devices or components were used, the same results could be achieved. pf = 1 √1 + ( thdi % 100 ) 2 (7) if the value of current harmonics decreases then the value of power factor is improved towards unity. the power factor can be calculated from above equation. 9. conclusion the findings of the simulation indicate that the application of the filter will reduce the power loss, and as a result, will contribute to the reduction of both energy consumption and the cost of the electricity. the quantity of power generated is now the single most important factor in the energy industry, despite the fact that the demand for electricity is expanding at an alarmingly rapid rate. voltage stabilization and an improvement in power quality are both necessities for the devices of today. harmonics compensation and power factor improvement are therefore required solutions for the aforementioned issues. the installation of the precisely rated filter protection device at the load centers is the primary responsibility of the companies that supply electricity. in addition to this, they are required to conduct routine inspections and maintenance. according to the findings of this study, it is possible to enhance the quality of electricity by utilizing both active and passive filters in conjunction with one another. as a consequence of this, it is believed that the hybrid filter, which consists of a passive filter connected in shunt and an active filter connected in series, is a worthwhile financial outcome to enhance the quality of the power and reduce the losses in the power structure. the findings of the simulation suggested that utilizing the filter would result in an increase in the power factor as well as a reduction in the power losses caused by harmonic distortion. although, harmonic compensation often involves complex algorithms and calculations. when using a hybrid filter to compensate for harmonics, the complexity can increase further as multiple filtering techniques are combined. this increased complexity may require more computational resources and processing power, making real-time implementation more challenging. moreover, hybrid filters used for harmonic compensation typically involve several parameters that need to be tuned and optimized. finding the optimal values for these parameters can be time-consuming and may require expertise in the underlying filtering techniques. improper parameter tuning can lead to suboptimal performance or even instability in the compensation process. hence, there is always a room exist to further improve and enhance the efficiency of the filter. it's important to note that the drawbacks and shortcomings mentioned above are not inherent to all hybrid filters for harmonic compensation. they may vary depending on the specific combination of filtering techniques, the characteristics of the harmonics, and the implementation details. arslan arshad (et al.), power quality improvement and harmonics compensation using hybrid filter (pp. 11 22) sukkur iba journal of emerging technologies sjet | vol. 6 no. 1 january – june 2023 21 references [1]. oka, v. n. meshcheryakov, a. m. evseev and a. i. boikov, "active energy filter for compensation of harmonic distortion in motor soft starter," 2018 17th international ural conference on ac electric drives (aced), ekaterinburg, 2018, pp. 1-5. [2]. a. g. peter and k. a. saha, "comparative study of harmonics reduction and power factor enhancement of six and 12-pulses hvdc system using passive and shunt apfs harmonic filters," 2018 international conference on the domestic use of energy (due), cape town, 2018, pp. 1-10. [3]. s. hamasaki, k. nakahara and m. tuji, "harmonics compensation in high frequency range of active power filter with sic-mosfet inverter in digital control system," 2018 international power electronics conference (ipecniigata 2018 -ecce asia), niigata, 2018, pp. 3237-3242. [4]. s. ivanov, m. ciontu, d. sacerdotianu and a. radu, "simple control strategies of the active filters within a unified power quality conditioner (upqc)," 2017 international conference on modern power systems (mps), cluj-napoca, 2017, pp. 1-4. [5]. j. he and beihua liang, "selective harmonic compensation using active power filter with enhanced double-loop controller," 2016 ieee 8th international power electronics and motion control conference (ipemc-ecce asia), hefei, 2016, pp. 2714-2718. [6]. s. c. ferreira, r. b. gonzatti, r. r. pereira, c. h. da silva, l. e. b. da silva and g. lambert-torres, "finite control set model predictive control for dynamic reactive power compensation with hybrid active power filters," in ieee transactions on industrial electronics, vol. 65, no. 3, pp. 2608-2617, march 2018. [7]. a. panchbhai, s. parmar and n. prajapati, "shunt active filter for harmonic and reactive power compensation using p-q theory," 2017 international conference on power and embedded drive control (icpedc), chennai, 2017, pp. 260-264. [8]. thomas, jaime prieto, et al. "assessment on apparent power indices with hybrid active power filters." compatibility, power electronics and power engineering (cpe-powereng), 2017 11th ieee international conference on. ieee, 2017. [9]. j. tandekar, a. ojha and s. jain, "real time implementation of multilevel converter based shunt active power filter for harmonic compensation in distribution system," 2016 7th india international conference on power electronics (iicpe), patiala, 2016, pp. 15. [10]. p. salmerón revuelta, s. pérez litrán, and j. prieto thomas, "6 hybrid filters: series active power filters and shunt passive filters," in active power line conditioners, ed san diego: academic press, 2016, pp. 189-229. [11]. tahmid, rashik, and shameem ahmad. "power quality improvement by using shunt hybrid active power filter." electrical, computer and communication engineering (ecce), international conference on. ieee, 2017. [12]. swain, sushree diptimayee, pravat kumar ray, and kanungo barada mohanty. "a real time study of hybrid series active power filter for power quality improvement." power electronics, intelligent control and energy systems (icpeices), ieee international conference on. ieee, 2016. [13]. j. s. sanjay and b. misra, "power quality improvement for non linear load applications using passive filters," 2019 3rd international arslan arshad (et al.), power quality improvement and harmonics compensation using hybrid filter (pp. 11 22) sukkur iba journal of emerging technologies sjet | vol. 6 no. 1 january – june 2023 22 conference on recent developments in control, automation & power engineering (rdcape), noida, india, 2019, pp. 585-589, doi: 10.1109/rdcape47089.2019.8979035. [14]. m. sakamoto, and h. haga. “control method for single-phase active filter using universal smart power module (uspm)” in ieej journal of industry applications, vol. 12, no. 3, pp.273-280, 2023. [15]. t.l. lee, j.c. li and p.t. cheng. “discrete frequency tuning active filter for power system harmonics” in ieee transactions on power electronics, vol. 24, no. 5, pp.1209-1217, 2009. format template vol. 6, no. 1 | january – june 2023 sjet | p-issn: 2616-7069 |e-issn: 2617-3115 | vol. 6 no. 1 january – june 2023 23 harris’ hawks optimization-tuned density-based clustering muhammad shoaib omar1, syed muhammad waqas2, kashif talpur3*, sumra khan4, shakeel ahmad3 abstract: clustering is a machine learning technique that groups data samples based on similarity and identifies outliers with distinct features. density-based clustering outperforms other methods because it can handle arbitrary shapes of clustering distributions. however, it has a limitation of requiring empirical values for the cluster center and the nominal distance between the cluster center and other data points. these values affect the accuracy and the number of clusters obtained by the algorithm. this paper proposes a solution to optimize these parameters using harris’ hawks optimization (hho), an efficient optimization technique that balances exploration and exploitation and avoids stagnation in later iterations. the proposed hho-tuned density-based clustering achieves better performance as compared to other optimizers used in this work. this research also provides a reference for designing efficient clustering techniques for complexshaped datasets. keywords: machine learning; density-based clustering; metaheuristic algorithm; harris’ hawk optimization; clustering. 1. introduction unlabeled data is being generated exponentially by today’s information systems, which demands accuracy and high efficiency for analysis, in order to draw logical conclusions. clustering is the most studied and broadly used learning technique of its kind. it endeavors to divide a dataset into numerous usually separate subsets where each one is called a cluster. through this partition, each cluster may assimilate to some prospective categories, which the clustering algorithm is not aware of prior to working on it. based on the diverse learning approaches, researchers have considered many types of clustering 1 department of computer science, bahria university, karachi, pakistan 2 department of computer science, muhammad ali jinnah university, karachi, pakistan 3 department of science and engineering, solent university, southampton, united kingdom 4 department of information technology, salim habib university, karachi, pakistan corresponding author: [kashif.talpur@solent.ac.uk] algorithms, based on different features. these methods can be characterized into densitybased, portioning-based, hierarchy-based, model-based, and grid-based approaches [1]. a density-based clustering algorithm groups data points based on cut-off distance and minimum number of points in each radius. in 1996, an algorithm was proposed by martin ester et. al [2] as a clustering algorithm with arbitrary cluster shapes without specifying the number of clusters beforehand, and they named it density-based spatial clustering of applications with noise (dbscan). dbscan, by design, has several advantages when compared to its counterparts; as it does muhammad shoaib omar (et al.), harris’ hawks optimization-tuned density-based clustering (pp. 23 34) sukkur iba journal of emerging technologies sjet | vol. 6 no. 1 january – june 2023 24 not need to define the number of clusters as prior information, and it can work with datasets with varying densities. dbscan algorithm is a novel technique to deal with unlabeled data as it promises great success. initially, using dbscan, several past works have focused on clustering spatial data, however, its success has been noticed in various other data complexities [3,4,5]. because it groups data points with respect to density, clusters in dbscan are considered to be the regions with dense data points, and these clusters are separated by the regions having low density, or noise. this core functionality of this algorithm makes it effective in identifying clusters with unusual arbitrary shapes, as well as, determining noise or outliers [6]. dbscan performs clustering with the help of two user-defined parameters: epsilon (ɛ) which is the cluster radius and minimum points (minpts) to be present in that radius. despite its efficacy in clustering applications, dbscan faces same limitations as other clustering methods, such as the determination of optimal values for userdefined parameters (ɛ and minpts) is difficult and problem specific. this demands a significant amount of personal experience or several experimental trials, hence limiting its extensive use. to address the said problem, different approaches have been proposed in the literature. lai et. al [7] used multi-verse optimizer (mvo) algorithm for automatic selection of ɛ and minpts parameters. the authors claimed to have achieved improved clustering performance of dbscan while employed on three public datasets. in this research, the authors first improved mvo and then used it for finding the optimum range of values for the dbscan parameters. researchers in [8] proposed the unsupervised patterns in multi-dimensional data, also known as data cubes, using genetic algorithm (ga). while tuning ga parameters (mutation and crossover), the researchers utilized fuzzy inference mechanisms: mamdani's rules and takagi-sugeno's rules. when compared with the existing dbscan, they found the gatuned dbscan achieved better clustering quality on six datasets of data cubes, for olap (online analytical processing) purposes. another successful application of metaheuristic algorithms on dbscan parameter optimization is done by zhu et. al [9] where the authors used harmony search (hs) optimization algorithm for the similar purposes. the experiments of this new clustering scheme, on six clustering problems of varying complexity, showed superior performance than the canonical dbscan, based on rand index (ri) and jaccard coefficient (jc) evaluation metrics. these significant research efforts have developed and extended the applicability of dbscan by benefiting from optimization capability of metaheuristic algorithms that select more reasonable values of clustering parameters from an optimal range. metaheuristic algorithms have proved to be powerful optimization techniques, while implemented over a range of optimization problems. by mimicking intelligent behaviors from nature, researchers have developed efficient search mechanisms. the wellestablished metaheuristic algorithms are particle swarm optimization (pso) [10], artificial bee colony (abc) [11], genetic algorithms (ga) [12], and ant colony optimization (aco) [13]. however, some of the latest counterparts have also been effective in research, such as grey wolf optimization (gwo) [14], archimedes optimization algorithm (aoa) [15], honey badger algorithm (hba) [16], and chaos game optimization (cgo) [17]. these and many others are used in data mining tasks [18], wireless sensors node localization [19], power flow optimization in smart grids [20], stock price prediction [21], etc. most of these metaheuristic algorithms are based on collective intelligence displayed by a group of search agents, which makes them simple, efficient, and ready to deploy on any optimization problem. harris' hawks optimization (hho) is a recent induction in the paradigm of optimization methods, developed by heidari et. al paradigm of optimization methods, developed by heidari et. al [22]. hho maintains a robust global search strategy by integrating balanced exploration and muhammad shoaib omar (et al.), harris’ hawks optimization-tuned density-based clustering (pp. 23 34) sukkur iba journal of emerging technologies sjet | vol. 6 no. 1 january – june 2023 25 exploitation tools. its performance is rightfully validated by several research works, such as engineering design optimization [23], satellite imaging breakdown threshold optimization [24], drug design and discovery [25] and wireless sensor node localization [26], and many other constrained and unconstrained problems [7,27,28,29]. keeping in view the outstanding global search ability of hho and its effective exploration and exploitation strategies, we utilize it to improve clustering performance of dbscan. we optimize the dbscan parameters (ɛ and minpts) using hho, since the manual parameter selection process is based on trial and error which is considered as an ineffective approach. the optimal parameters result in high clustering accuracy. the rest of the paper is organized as follows. the upcoming section explains about materials and methods like fundamentals of dbscan and hho. section \ref{sec:materialsandmethods} elaborates on the methodology of hho for dbscan parameter optimization. the experimental settings and results are discussed in section \ref{sec:results}, whereas section \ref{sec:conclusion} duly concludes the findings of this research. 2. materials and methods 2.1. dbscan clustering algorithm dbscan (density-based spatial clustering of applications with noise), introduced by martin et al. in 1996 [2], is a density-based clustering algorithm, which identifies clusters by density of objects found in dense regions. the benefits of this technique are that it can identify clusters of arbitrary shapes, clusters within a cluster (nested clusters) as well as outliers (the points not belonging to any cluster). this algorithm is mainly based on two integer value parameters: ɛ and minpts, where ɛ is the maximum radius of the neighborhood and minpts are the minimum number of points in that radius. a user has to provide values of these two parameters based on some past experience or on hit and trial basis. these two parameters play an important role in accuracy of the clusters being identified by the algorithm. let's say if ɛ is a larger number, it will include many points in a cluster. some of the points might occur there, which may not actually belong to that cluster. on the contrary, if it is initialized with a small value, it may create more clusters as compared to the correct number of required clusters. the parameter minpts also acts in same manner. dbscan also identifies outliers, the points that do not belong to any cluster. there are some core definitions related to the dbscan, which are:  ɛ-neighborhood: points within the radius of the center point ɛ.  core point: a point within its radius has at least minimum points (minpts).  boundary point: a point that is not a center point and has less than minimum points in its neighborhood but at least has one center point within its radius.  noise points: points that are neither midpoints nor boundary points and do not belong to any cluster.  direct-density reachable: if point q is within the radius and p is the core point, then point q is directly density accessible from point p.  density-reachable: point q is the density reachable of point p if point q is within the radius and point p is not a center point. point q is connected to point p through other points (q1, q2, q3, ... qn).  density-connectivity: if points p and q are densities accessible from center point o, then points p and q are connected to each other relative to point o.  cluster: defined as the largest set of densely connected points. the algorithmic steps of dbscan are illustrated in algorithm 1. muhammad shoaib omar (et al.), harris’ hawks optimization-tuned density-based clustering (pp. 23 34) sukkur iba journal of emerging technologies sjet | vol. 6 no. 1 january – june 2023 26 algorithm 1: pseudo-code of dbscan procedure dbscan(dataset x, 𝜖, minpts) step-1: explore all core points in the eld space x using 𝜖 and minpts and add it to the set of core objects. a core point is when |nɛ(xi)| > minpts step-2: select any core object from the set and make a cluster with other core points using ɛ and minpts until all core points are visited and no more core point is left. step-3: add unvisited border points in the current cluster one-by-one. but border point cannot extend the cluster further as it is not a core point. step-4: if a point is neither core nor a border point, mark it as noise and put it in a separate set, and label it. step-5: when all border points are added to the cluster; pick another core point for the set and repeat above steps until a cluster is made. return labeled data space of cluster index. end procedure 2.2. harris' hawks optimization in 2019, ali asghar et al. [22] presented an optimization technique after observing the hunting behavior of harris' hawks, which is called harris' hawks optimization (hho). this algorithm exhibits the hunting behavior of the harris' hawks. for these hawks, the primary tactic for hunting prey is the “raid”. this strategy is also known as the “seven-kill strategy”. in this strategy, sometimes the surprised prey is caught within a few seconds or otherwise, these attacks are kept in continuity till the prey is caught. this search approach may include several brief and smart dives from different directions within seconds and minutes to confuse the exhausted prey that it is now and then is caught by the attacking hawk. the harris' hawks can apply a variety of attacking styles keeping in view the hunting environment, escaping behavior, and energy of their prey. there may be some hard and soft besieges while attacking the prey till it is finally caught. these abruptly changing attacking behavior of the hawks are beneficial in a way that this strategy brings rabbits to a complete exhaustion and become defenselessness. the hho algorithm consists of three phases, in which these attacks are taken place. these are: 2.2.1. exploration phase firstly, in the exploration phase, hawks wait in the hunting field and use their extended and strong visual power to locate a prey (rabbit). sometimes the rabbits are explored very easily and other times, they have to wait for hours to locate one. if the hawks are unable to locate any rabbit for a certain period of time, they change their place and use random perching in other locations to look for the prey. this strategy in the form of mathematical representation is depicted in eq. 1: 𝑋(𝑡 + 1) = { 𝑋𝑟𝑎𝑛𝑑(𝑡) − 𝑟1|𝑋𝑟𝑎𝑛𝑑(𝑡) − 2𝑟2𝑋(𝑡)| if 𝑞 ≥ 0.5 𝑋𝑟𝑎𝑏𝑏𝑖𝑡 (𝑡) − 𝑟1|𝑋𝑚(𝑡) − 𝑟3(𝑈𝐵 − 𝑟4𝐿𝐵)| otherwise (1) where xrabbit(t) is the current optimal solution whereas the next possible solution in terms of hawk's position is denoted by x(t+1). x(t), xrand(t), and xm(t) show the positions of all hawks (total solutions-set), randomly selected hawks, and average positions, respectively. the lower and upper bounds of the search space are given by lb and ub, whereas r1-r4 represent random variables between [0-1]. 2.2.2. the transition from exploration to exploitation this is the second phase of hho algorithm, which takes place between exploration and exploitation. when a prey is found, then different exploitation behaviors are used to reduce its escaping energy so that some of the hawks are able to catch it easily. in hho, it is called energy component, formulated in eq. 2: 𝐸 = 2𝐸0(1 − 𝑡 𝑡𝑚𝑎𝑥 ) (2) muhammad shoaib omar (et al.), harris’ hawks optimization-tuned density-based clustering (pp. 23 34) sukkur iba journal of emerging technologies sjet | vol. 6 no. 1 january – june 2023 27 where initial energy of the rabbit is denoted by e0, and t and tmax represent current and maximum number of iterations respectively. 2.2.3. exploitation phase the hawks bout on their target using different attacking techniques as required in that situation. the situation depicts the escaping pattern of the prey and attacking style of the hawks, and energy of the rabbits as well. there are four likely strategies in the hho algorithms. these are as depicted in eqs. 3 6:  soft besiege: if chance of escape ≥0.5 and absolute energy ≥0.5: 𝑋(𝑡 + 1) = ∆𝑋(𝑡) − 𝐸|𝐽𝑋𝑟𝑎𝑏𝑏𝑖𝑡 (𝑡) − 𝑋(𝑡)| ∆𝑋(𝑡) = 𝑋𝑟𝑎𝑏𝑏𝑖𝑡 (𝑡) − 𝑋(𝑡), 𝐽 = 2(1 − 𝑟5) (3) where ∆𝑋(𝑡) is the difference between the current position of a hawk x(t) and rabbit 𝑋𝑟𝑎𝑏𝑏𝑖𝑡 and r5 being a random variable.  hard besiege: if chance of escape ≥0.5 and absolute energy <0.5: 𝑋(𝑡 + 1) = 𝑋𝑟𝑎𝑏𝑏𝑖𝑡 (𝑡) − 𝐸|∆𝑋(𝑡)| (4)  soft besiege with rapid progressive dives: if chance of escape <0.5 and absolute energy ≥0.5: 𝑋(𝑡 + 1) = { 𝑌 𝑖𝑓 f(y ) < f(x(t)), 𝑌 = 𝑋𝑟𝑎𝑏𝑏𝑖𝑡 (𝑡) − 𝐸|𝐽𝑋𝑟𝑎𝑏𝑏𝑖𝑡 (𝑡) − 𝑋(𝑡)| 𝑍 𝑖𝑓 f(z ) < f(x(t)), 𝑍 = 𝑌 + 𝑆 × 𝐿𝑒𝑣𝑦𝐹𝑙𝑖𝑔ℎ𝑡(𝐷) (5) where d and s denote problem dimensions and a random vector of size d, respectively. levyflight(d) is levy flight function.  hard besiege with rapid progressive dives: if chance of escape <0.5 and absolute energy <0.5:  𝑋(𝑡 + 1) = { 𝑌 𝑖𝑓 f(y ) < f(x(t)), 𝑌 = 𝑋𝑟𝑎𝑏𝑏𝑖𝑡 (𝑡) − 𝐸|𝐽𝑋𝑟𝑎𝑏𝑏𝑖𝑡 (𝑡)−𝑋𝑚 (𝑡)| 𝑍 𝑖𝑓 f(z ) < f(x(t)), 𝑍 = 𝑌 + 𝑆 × 𝐿𝑒𝑣𝑦𝐹𝑙𝑖𝑔ℎ𝑡(𝐷) (6) the step-by-step procedure of hho algorithm can be defined in algorithm 2. algorithm 2: pseudo-code of hho algorithm procedure hho(dataset x, 𝜖, minpts) initialization of population xi, (i=1, 2,..., n) while t< tmax calculate fitness values of hawks and best location of rabbit for each hawk xi(t) if e≥1 then exploration and position update via eq. 1 else exploitation and position update via eqs. 3-6 end for end while return optimum solution xrabbit end procedure as can be seen in algorithm 2, it first initializes the population and then enters the exploration phase using eq. 1 until it finds some prey in the search space. it will keep on searching and will wait until it finds a prey. after locating the prey, it will transit from the exploration to the exploitation phase using eq. 2. then it will make some attacking movements using four strategies as mentioned using eq. 3 to eq. 6 called soft and soft besieges and soft/ hard besieges with progressive dives. 2.3. hho-tuned dbscan in this research, hho and dbscan are integrated, in order to enhance clustering capability of the dbscan algorithm. here, dbscan is integrated with hho in such a way that it achieves highest accurate values of ɛ and minpts. as can be seen from algorithm 3 the dbscan algorithm is called within hho. hho provides the values of best-fit rabbit and its energy as candidate values of ɛ and minpts, which are evaluated and then passed to hho. the provided values are muhammad shoaib omar (et al.), harris’ hawks optimization-tuned density-based clustering (pp. 23 34) sukkur iba journal of emerging technologies sjet | vol. 6 no. 1 january – june 2023 28 compared to each other and convergence of the hho is analyzed. at the point where it converges at global minima and with lowest clustering error, it is our desired values for ɛ and minpts. the hho is used to search dbscan parameters for optimal clustering accuracy, as shown in algorithm 3. algorithm 2: pseudo-code of hhodbscan algorithm procedure hho-dbscan(solution size n, maximum iterations tmax) initialization of population xi (i = 1, 2,..., n) while t<tmax for each xi(t) x =xi(t) ɛ =x1 and minpts = x2 calculate fitness of dbscan with given parameters end for for each hawk xi(t) if e≥1 then exploration and position update via eqs. 1 and 2 else exploitation and position update via eqs. 3-6 end for end while return optimum solution xrabbit end procedure 3. experimental results to evaluate the hho-tuned dbscan performance, we used a computing machine with a 1tb hard drive, 32 gb ram, and a core i7 processor, on a windows 10 pc, the code was developed in matlab r2016a. for experiments, we used three real-world datasets namely seed, segment, and iris. and, four synthetic datasets namely flame, path-based, d31, and compound. 3.1. hho-dbscan on real-world datasets three university of california machine learning datasets [30] are chosen: iris has three classes and four attributes; seeds has three classes and seven attributes; and segment has seven classes and nineteen attributes. the results of hho-dbscan are compared with improved multi-verse optimizer (imvo2) from lai et al. [7] which is used for searching best value for ɛ parameter. to evaluate imvo2 search ability, the researchers chose 500 points at random from each interval [ɛmin, ɛmax] as the value of ɛ, and used it in dbscan. whereas, our proposed method hho is being more effective as the results indicated that it shows the highest accuracy in every case as compared to imvo2. hho-tuned dbscan achieves outstanding results, serving as a model for developing efficient clustering approaches for complex clustering-shaped datasets. table 1 presents comparison results of hho-dbscan and other counterparts (metaheuristic improved versions of dbscan i.e., pso-dbscan [31], acodbscan [32], and imvo-dbscan [7]) with respect to accuracy metric on real-world and synthetic datasets. it can be observed from the results that hho-dbscan outperformed the other improved versions of dbscan, as it scores high in each evaluation. the indices of evaluation metric are almost near to 100\% in each case, which speaks of efficacy of the proposed method. in fig. 1, the trend of optimal accuracy of dbscan clustering for seeds, iris, and segment is consistent with the tendency of clustering accuracy in their subsets, when minpts takes different values. also, the optimal parameter minpts is the same, which are 18, 3, and 3 respectively in imvo2. the optimal minpts is selected and then optimized for the parameter ɛ. the results are shown in table 1, which indicates that the ɛ interval muhammad shoaib omar (et al.), harris’ hawks optimization-tuned density-based clustering (pp. 23 34) sukkur iba journal of emerging technologies sjet | vol. 6 no. 1 january – june 2023 29 corresponds to the optimal clustering accuracy of all the samples in a dataset. furthermore, the interval of ɛ corresponding to the optimal clustering accuracy of all the samples in the dataset overlaps with the range of ɛ examined by imvo2 to its subset in table 1. on the other hand, when the proposed technique hho-dbscan is applied to seed subsets, seeds, iris subsets, iris, segment subsets, and segments, the accuracy obtained is 95.05\%, 89.52\%, 99.47\%, 84.66\%, 76.42\%, and 66.02\%, respectively. the results show that by using known label samples to tune the dbscan parameters, we can mine unknown label samples, which is unattainable with supervised learning methods. table 2. evaluation of hho-dbscan on real-world datasets we can identify the optimal clustering accuracy of dbscan by incorporating hho to optimize the parameters of dbscan. this helps us to choose a more suitable ɛ value for dbscan clustering. fig. 1 depicts a graph of various datasets on imvo2 and the proposed method with minpts ranging from 1 to 40 on the x-axis and accuracy on the y-axis. the graphs indicate accuracy of the proposed method is higher than imvo2-dbscan, so we can conclude that our method is reliable, as it achieves the highest accuracy in every dataset. dbscan parameters determination and optimization for a dataset and its subset is presented in table 2. in fig. 1, the best dbscan clustering accuracy trend for seeds, iris, and segment is consistent with the clustering accuracy trend of their subsets where minpts is provided with different values. moreover, the optimal minpts parameters are the same, 18, 3, and 3 in imvo2, respectively. on the other hand, when the proposed technique hho-dbscan is applied to seed subsets, seeds, iris subsets, iris, segment subsets, and segments, the accuracy obtained is 95.05\%, 89.52\%, 99.47\%, 84.66\%, 76.42\%, and 66.02\%, respectively. the results show that by using known label samples to tune the dbscan parameters, we can mine unknown label samples. it can be seen from table 2 that purity is more than 90\% i.e., 0.9505 and 0.9948 in seeds subset and iris subset, which clearly speaks of the results validity. the nmi, ri and table 1. accuracy comparison between hho-dbscan and others based on optimized values for dbscan parameters. muhammad shoaib omar (et al.), harris’ hawks optimization-tuned density-based clustering (pp. 23 34) sukkur iba journal of emerging technologies sjet | vol. 6 no. 1 january – june 2023 30 ari of segment subset are 0.9939, 0.9799, and 0.9887, respectively. for the segment, values of nmi, ri, and ari are 0.8834, 0.9014, and 0.9112, which are also promising. however, nmi, ri, and ari indices of seeds and seeds subsets are not as expected, which shows that the method did not perform well on this dataset because it consists of 19 attributes and 7 classes of diverse natures. since this dataset belongs to segments of a picture, hence it contains a high variance and dispersion among the values. the diverse nature of these values and increased number of classes, the results generated are not as expected. fig. 1. accuracy comparison between imvo2-dbscan and hho-dbscan based on optimized values for minpts parameter. muhammad shoaib omar (et al.), harris’ hawks optimization-tuned density-based clustering (pp. 23 34) sukkur iba journal of emerging technologies sjet | vol. 6 no. 1 january – june 2023 31 3.2. hho-dbscan on synthetic datasets the proposed method is then implemented on four synthetic datasets including compound, d31, flame, and path-based. here, compound dataset has 788 points with 2 dimensions and 7 clusters. whereas the d31 dataset which is made up of 31 similar 2-d gaussian distributions. the path-based dataset contains 300 points and has 2 dimensions and contains 6 clusters. the flame dataset has 240 data points, 2 dimensions, and contains 2 clusters. the clustering results of hhodbscan are evaluated on synthetic datasets based on purity, nmi, ri, and the ari evaluation measures. on compound, hho-dbscan achieves the purity of 0.9607, nmi value.9510, ri value 0.9863 and, the ari value 0.9755. overall, it achieves better results by using an efficient optimization method for finding ɛ parameter on different minimum parameter (minpts) ranging from 1 to 40. the clustering results of hho-dbscan on compound are shown in fig.2(a), from which it can be inferred that the outcomes of projected solution are outperforming. the d31 is made up of 31 similar 2-d gaussian distributions. while applying hho-dbscan, we get the highest purity value of 0.9900 for the d31 dataset. we can also suggest from the fig.2(b) that the proposed approach is reliable and produces the best results. the clustering results of hho-dbscan on the flame dataset are shown in fig.2(c) which clearly illustrate that this strategy for selecting dbscan parameters is the most efficient method available. hho provides enhanced exploration and exploitation capabilities, which aids in avoiding solution stagnation in subsequent rounds. table 2 presents that using the flame dataset, we attain purity of 0.9988 and nmi of 0.9714, while the ri and ari are 0.9949 and 0.9717. fig.2(d) demonstrates clustering results on the pathbased dataset when hho-dbscan is applied muhammad shoaib omar (et al.), harris’ hawks optimization-tuned density-based clustering (pp. 23 34) sukkur iba journal of emerging technologies sjet | vol. 6 no. 1 january – june 2023 32 to that data the highest results we achieve as purity, nmi, ri, and ari are 0.9533, 0.9144, 0.9438, and 0.9398 respectively. from the overall results, it can be concluded that hho is an efficient method for achieving the optimal values for the parameters for dbscan. the application of hho to optimize dbscan parameters, allows us to discover the best clustering accuracy. the proposed algorithm optimally finds values of ɛ and minpts parameters to create clusters with maximum accuracy. the combination of dbscan and hho algorithms enhanced the process of clustering with accuracy improvement. 4. conclusion dbscan is a clustering technique which has achieved appreciation from researchers and practitioners, mainly due to its ability to detect outliers and clustering efficiency for the data points distributed in arbitrary manner. however, manual selection of the dbscan parameters (ɛ and minpts) is a cumbersome job, as it requires past experience, as well as, several trials. this highly affects accuracy of the algorithm, since every dataset or clustering problem demands separate efforts to find best suitable dbscan parameters. this demands an effective approach to selecting these parameters in an automatic manner. using metaheuristic algorithms, for this purpose, has overall resolved the problem, but with the existence of numerous optimization methods, the choice of the efficient one is crucial. this study applied an efficient metaheuristic algorithm hho which has already generated comparatively better optimization results for a variety of optimization problems. both of the algorithms are successfully integrated to achieve the objective of automatically getting values of minpts and eps. these values are metaheuristically calculated by optimization algorithm hho. the results and comparison show that the calculated values are more accurate as compared to previous methods proposed y different researchers. the evaluation metrics used in this study indicate that the proposed method outperforms its counterpart methods. moreover efficiency of the proposed model is also tested with other alike methods found in literature. based on insightful comparative analysis performed for hho-dbscan and one of the recently introduced imvo2-dbscan methods, it can be asserted that hho is able to optimize dbscan parameters more efficiently, as it helps dbscan achieve clustering accuracy. although the proposed method performs comparatively better for various datasets however, its performance is observed low in datasets having diverse data points. the lack of smoothness of data due to dispersion caused the proposed method to drop its efficiency, since it fails to identify the values of ɛ and minpts correctly. moreover, remaining in our limited scope, the proposed solution is for now applied to real-world and synthetic datasets however, it can also be applied to industry/engineering problems to testify to its performance. moreover, since dbscan, sometimes fails to perform properly in largescale and high-dimensional datasets, so in future dbscan and hho can also be improved to work with large and highdimensional datasets. references [1] bie, r., mehmood, r., ruan, s., sun, y., dawood, h.: adaptive fuzzy clustering by fast search and find of density peaks. personal and ubiquitous computing 20, 785-793 (2016) [2] ester, m., kriegel, h.p., sander, j., xu, x.: a density-based algorithm for discovering clusters in large spatial databases with noise. in: proceedings of the second international conference on knowledge discovery and data mining, kdd'96, p. 226-231. aaai press (1996). [3] ali, t., asghar, s., sajid, n.a.: critical analysis of dbscan variations. in: 2010 international conference on information and emerging technologies, pp.1-6. ieee (2010). [4] birant, d., kut, a.: st-dbscan: an algorithm for clustering spatial{temporal data. data & knowledge engineering 60(1), 208-221 (2007). muhammad shoaib omar (et al.), harris’ hawks optimization-tuned density-based clustering (pp. 23 34) sukkur iba journal of emerging technologies sjet | vol. 6 no. 1 january – june 2023 33 [5] viswanath, p., babu, v.s.: rough-dbscan: a fast hybrid density based clustering method for large data sets. pattern recognition letters 30(16), 1477-1488 (2009). [6] andrade, g., ramos, g., madeira, d., sachetto, r., ferreira, r., rocha, l.: gdbscan: a gpu accelerated algorithm for density-based clustering. procedia computer science 18, 369-378 (2013). [7] lai, w., zhou, m., hu, f., bian, k., song, q.: a new dbscan parameters determination method based on improved mvo. ieee access 7, 104,085-104,095 (2019). [8] rad, m.h., abdolrazzagh-nezhad, m.: data cube clustering with improved dbscan based on fuzzy logic and genetic algorithm: designing and improving data cube clustering. information technology and control 49(1), 127-143 (2020). [9] zhu, q., tang, x., elahi, a.: application of the novel harmony search optimization algorithm for dbscan clustering. expert systems with applications 178, 115,054 (2021). [10] eberhart, r., kennedy, j.: a new optimizer using particle swarm theory. in: mhs'95. proceedings of the sixth international symposium on micro machine and human science, pp. 39-43. ieee (1995). [11] karaboga, d., et al.: an idea based on honey bee swarm for numerical optimization. tech. rep., technical report-tr06, erciyes university, engineering faculty, computer . . . (2005). [12] holland, j.h.: adaptation in natural and artificial systems: an introductory analysis with applications to biology, control, and artificial intelligence. mit press (1992). [13] dorigo, m., gambardella, l.m.: ant colony system: a cooperative learning approach to the traveling salesman problem. ieee transactions on evolutionary computation 1(1), 53-66 (1997). [14] mirjalili, s., mirjalili, s.m., lewis, a.: grey wolf optimizer. advances in engineering software 69, 46-61 (2014). [15] hashim, f.a., hussain, k., houssein, e.h., mabrouk, m.s., al-atabany, w.: archimedes optimization algorithm: a new metaheuristic algorithm for solving optimization problems. applied intelligence 51, 1531-1551 (2021). [16] hashim, f.a., houssein, e.h., hussain, k., mabrouk, m.s., al-atabany, w.: honey badger algorithm: new metaheuristic algorithm for solving optimization problems. mathematics and computers in simulation 192, 84-110 (2022). [17] talatahari, s., azizi, m.: chaos game optimization: a novel metaheuristic algorithm. artificial intelligence review 54, 917-1004 (2021). [18] dhaenens, c., jourdan, l.: metaheuristics for data mining: survey and opportunities for big data. annals of operations research 314(1), 117-140 (2022). [19] tsai, c.w., tsai, p.w., pan, j.s., chao, h.c.: metaheuristics for the deployment problem of wsn: a review. microprocessors and microsystems 39(8), 1305-1317 (2015). [20] papadimitrakis, m., giamarelos, n., stogiannos, m., zois, e., livanos, n.i., alexandridis, a.: metaheuristic search in smart grid: a review with emphasis on planning, scheduling and power flow optimization applications. renewable and sustainable energy reviews 145, 111,072 (2021). [21] shahvaroughi farahani, m., razavi hajiagha, s.h.: forecasting stock price using integrated artificial neural network and metaheuristic algorithms compared to time series models. soft computing 25(13), 8483-8513 (2021). [22] heidari, a.a., mirjalili, s., faris, h., aljarah, i., mafarja, m., chen, h.: harris hawks optimization: algorithm and applications. future generation computer systems 97, 849872 (2019). [23] gupta, s., abderazek, h., yildiz, b.s., yildiz, a.r., mirjalili, s., sait, s.m.: comparison of metaheuristic optimization algorithms for solving constrained mechanical design optimization problems. expert systems with applications 183, 115,351 (2021). [24] jia, h., lang, c., oliva, d., song, w., peng, x.: dynamic harris hawks optimization with mutation mechanism for satellite image segmentation. remote sensing 11(12), 1421 (2019). [25] houssein, e.h., hosney, m.e., oliva, d., mohamed, w.m., hassaballah, m.: a novel hybrid harris hawks optimization and support vector machines for drug design and discovery. computers & chemical engineering 133, 106,656 (2020). [26] houssein, e.h., saad, m.r., hussain, k., zhu, w., shaban, h., hassaballah, m.: optimal sink node placement in large scale wireless sensor networks based on harris' hawk optimization algorithm. ieee access 8, 19,381-19,397 (2020). [27] rodriguez-esparza, e., zanella-calzada, l.a., oliva, d., heidari, a.a., zaldivar, d., perez-cisneros, m., foong, l.k.: an efficient harris hawks-inspired image segmentation method. expert systems with applications 155, 113,428 (2020) [28] ewees, a.a., abd elaziz, m.: performance analysis of chaotic multi-verse harris hawks muhammad shoaib omar (et al.), harris’ hawks optimization-tuned density-based clustering (pp. 23 34) sukkur iba journal of emerging technologies sjet | vol. 6 no. 1 january – june 2023 34 optimization: a case study on solving engineering problems. engineering applications of artificial intelligence 88, 103,370 (2020). [29] fan, q., chen, z., xia, z.: a novel quasireflected harris hawks optimization algorithm for global optimization problems. soft computing 24, 14,825-14,843 (2020). [30] dua, d., graff, c.: uci machine learning repository (2017). url http://archive.ics.uci.edu/ml. [31] alswaitti, m., albughdadi, m., isa, n.a.m.: density-based particle swarm optimization algorithm for data clustering. expert systems with applications 91, 170-186 (2018). [32] jiang, h., li, j., yi, s., wang, x., hu, x.: a new hybrid method based on partitioningbased dbscan and ant clustering. expert systems with applications 38(8), 9373-9381 (2011). format template vol. 2, no. 1 | january june 2019 sjet | p-issn: 2616-7069 | e-issn: 2617-3115 | vol. 2 | no. 1 | © 2019 sukkur iba 27 review on scr catalysts by focusing impacts of sulfur on scr performance ghazanfar mehdi1, song zhou1, yuanqing zhu1, zubair ali shah1, kishore chand2, raza waleed3, asif raza4, sanaullah4 abstract: marine diesel engines are extensively used for transportation and as well as for power generation purpose because of its higher durability, thermal and fuel efficiency than the gasoline engines. but the marine diesel engine produced severe nox emissions that are currently well discussed issue needed to be solved due to its serious health and environmental problems. at the same time, because of increasing stringent regulations of nox emissions it is necessary for ships to meet the international maritime organization (imo) tier iii regulations in nox emission control areas (eca). it is enforced for the vessels that are constructed on and after the 1st january 2016. therefore, a demand for well-functioning nox reduction technology is required. currently scr is the most dominant and mature technology used to reduce the nox with ammonia over the scr catalyst. scr catalyst is the core part of scr system; hence this review described the different types of catalysts and their behavior under different conditions. furthermore, the deactivation of scr catalyst occurs by different mechanisms; however, the most significant mechanism is sulfur poisoning. reaction temperature and availability of ammonia is also significant parameter for sulfur poisoning. therefore, it is necessary to investigate how sulfur behaves with scr catalysts. even though many studies have been performed on sulphur poisoning of catalysts but still requires complete understanding. this review covers the sulfur poisoning of vanadium and cu-zeolites based scr catalysts with mainly focus on cu-zeolites because of its sulfur sensitivity. keywords: marine diesel engine, selective catalsyt reduction; vanadium;cu zeolite; sulfur 1 college of energy and power engineering, harbin engineering university, harbin 150001, china 2 college of material science and chemical engineering, harbin engineering university, harbin 150001, china 3 college of underwater acoustic engineering, harbin engineering university, harbin 150001, china 4 college of mechanical and electrical engineering, harbin engineering university, harbin 150001, china corresponding author: ghazanfarmehdi22@gmail.com 1. introduction because of their high thermal efficiency and durability, marine diesel engines are extensively used for power generation as well as for transport purpose. however, only transportation sectors are producing almost world’s 30% greenhouse gases [1]. marine diesel engine emissions produced serious mailto:ghazanfarmehdi22@gmail.com ghazanfar mehdi (et al.), review on scr catalysts by focusing impacts of sulfur on scr performance (pp. 27 44) sukkur iba journal of emerging technologies sjet | volume 2 no. 1 january – june 2019 © sukkur iba university 28 environmental hazardous gases specially nox. the carbon monoxide (co), carbon dioxide (co2) and hydrocarbon (hc) exhaust emissions is much lower in marine diesel engines, as in comparison to automobile design engines and on the contrary, it produces more detrimental nitrogen oxides (nox) emissions [2]. nox emissions are produced due to the combustion process of diesel engine. there are three main sources of nox formation named as thermal nox, fuel nox and prompt nox. the involvement of fuel nox and prompt nox to the total nox emissions is negligible [4]. basically thermal nox is the major contributor of nox formation throughout the whole combustion process [3]. nox is very noxious, hazardous and it creates an irritation. it is responsible for the headache and nausea [5]. nox can react with existence of sunlight and other organic compounds to form ozone layer. in the troposphere ozone is named as ground level ozone. when nox is reacted with water, nitric acid can be formed which is the major source of acid rain [6]. in order to reduce nox from ships, many national governments and international organizations in the world have promulgated different regulations on shipping emissions, and also enforced strict requirements on nox emission in the emission control areas (eca) [7]. in 2016, imo tier iii standard on nox emission proposed by international maritime organization (imo) has already been enforced in north america emission control area (eca), including the east and west coast of the usa and caribbean [8]. due to the increasing stringent emission regulations, it is necessary for vessels to meet the imo tier iii legislations applied for ships constructed on and after the 1st january 2016 in nox emission control areas. fig. 1 represents the limits of nox legislations. it is enforced that, during the operation of ships nox emissions should not exceed 3.4g/kwh. in the requirement of tier iii nox emission decreased up to 75% as compared to imo tier ii [9]. currently three most mature technologies such as exhaust gas recirculation (egr), selective catalyst reduction (scr) and dual fuel are mostly used worldwide to control the nox as shown in fig. 2 [10]. it has been observed that in order to decrease the nox emission intensely and meet the requirements of imo tier iii, scr, egr and dual fuel can be the effect methods. scr and egr are the most feasible and mature techniques used to decrease the nox of two stroke marine diesel engines. but the dual fuel is not good fig. 1. represents the limits of nox legislations [9] option, because the low speed two stroke marine diesel engines are still using hfo (heavy fuel oil). but scr in comparison to egr is the front runner technology in marine diesel engine due to its higher denox efficiency [11]. in egr system nox can be reduced by diverting the exhaust flow of burned gases into combustion chamber. as the recirculated burned gas entered, it is responsible for lowering the adiabatic flame temperature. due to the lowering of in-cylinder temperature nox formation has been reduced. but as a result of temperature reduction, the efficiency of engine also decreased which tends to increase the fuel consumption. therefore, scr is the most ghazanfar mehdi (et al.), review on scr catalysts by focusing impacts of sulfur on scr performance (pp. 27 44) sukkur iba journal of emerging technologies sjet | volume 2 no. 1 january – june 2019 © sukkur iba university 29 fig. 2. nox removal technologies prominent and leading technology because it operates with higher efficiency without compromising on both flame temperature and nox conversion [12]. scr is the dominant technology used to meet the most recent emission standards due to its technical maturity, better fuel economy and low cost for the emission reduction. scr is means of converting nox into n2 and h2o by using catalyst and oxygen (o2) [13]. however, pressure drop occurs at scr catalyst therefore more efficient turbocharger is necessary for scr system. fig. 3. systematic representation of scr system as the nox is decreased into n2, between the temperature ranges of 300 400 °c, the load of engine must be 40% and above. ammonia (nh3) will start burning when the exhaust temperature of engine goes beyond the 400 °c which will make the system ineffective. scr catalyst reaction will become slow and undesirable reactions such as formation of ammonium sulfates will occur when the temperature goes below 270 °c, which ultimately destroy the catalyst. therefore, scr reaction is mainly restricted by the catalyst activity, species concentration and reaction temperature [14]. fig. 3 shows the systematic representation of scr system. 2. challenges related to scr system the major challenges involved with scr systems is the reduction of catalytic converter volume at low temperatures and the suitable dosing strategy for nh3 at frequently varying load conditions of the diesel engines. additionally, the risk associated concerning storing and handling of gaseous nh3 is significant and consequentially it is not commonly used as a reducing agent directly. for reasons of toxic nature of nh3, handling and storing problems, urea is the preferred substitute for nh3 as a reducing agent in automotive applications. the best procedure is injecting urea water solution (uws) in the form of spray to hot exhaust stream before the entry to the scr catalyst [15]. urea is an environmentally benign chemical which makes it more suitable for application of the scr process. urea is a fertilizer used in agriculture and available in a number of quality grades at a lower cost. development of urea-scr over nh3-scr has gained momentum due to various problems involved with the use of nh3. nh3 is corrosive, toxic in nature and also a secondary pollutant. in order to introduce nh3 into the exhaust gas stream, proper dosage control mechanism is required [16]. the main advantage with this scr system is high de-nox efficiency (90% or higher). the disadvantages involve the space required for the catalyst, high capital and operating costs, formation of other emissions (nh3 slip) and formation of undesirable species which may lead to catalyst poisoning and deactivation. the nh3 slip can be controlled by installing an oxidation catalyst after the scr system. although the scr system has some drawbacks, the technology has been chosen by the majority of the diesel engine manufactures due to absence of better technology to meet the stringent emission standards [15]. ghazanfar mehdi (et al.), review on scr catalysts by focusing impacts of sulfur on scr performance (pp. 27 44) sukkur iba journal of emerging technologies sjet | volume 2 no. 1 january – june 2019 © sukkur iba university 30 there are two main objectives related to scr system. • to minimize the nox emissions • to minimize the ammonia slip following factors should be controlled to get the maximum output in above two objectives. • design optimization • control system • temperature fluctuations • low operating temperature • poisonous species present in the catalyst • mechanical vibrations • flow variations throughout the low load operating conditions, exhaust temperature is also low; this will put direct effect on the chemical reaction of scr catalyst, which makes reaction slow at low temperature for characteristic composition of exhaust gas. variations of engine load influenced the flow rate of exhaust gas, temperature, and composition of exhaust gases. therefore, it is necessary to control the above factors to improve the nox conversion and to reduce the ammonia slip. in general, there is trade off relationship in between nox reduction and ammonia slip [17]. 3. research evolution of scr catalyst catalyst is the core part of scr system. it has been used for reducing the activation energy, nox decomposition temperature during reaction, to avoid the incidence of unwanted reactions, increase the amount of n2 in production side and by this means reaction efficiency has been improved. catalysts selection is the most important. particularly, the competent scr catalysts possessed the characteristics as listed below: • denox ability should be high • anti-poisoning capacity should be high • strong mechanical strength • operating temperature should be proper. 3.1. vanadium based scr catalysts (vscr) a vscr catalyst is the established technology, mostly used in mobile applications [18]. it is the cheapest of all scr catalysts [19] and also well known for sulfur tolerance [20]. vcrs operates approximately in the temperature range of 280-500 oc [19, 21, 22]. it is also used at low temperatures, but as a result low nox removal efficiency occurs. a vscr catalyst is mainly composed with the mixture of wo3/ v2o5/tio2, where, wo3 is the thermal promoter and used to increase the catalyst acidity, v2o5 is worked as an active component and tio2 is added as a carrier material [20]. the main disadvantage of vscr is the sudden decline in the performance of acidity and selectivity at the higher temperatures. deterioration of catalyst or alkali poisoning starts when the temperature window in between of 550-600 oc [18]. toxicity of vanadium species is also an important issue [19]. 3.2. cu-zeolites based scr during the last few years, cu-zeolites based scr catalysts becomes the most preferred catalyst because of its high performance [19]. it is commonly used in movable applications [23]. the key benefits related to cu-zeolites based scr catalysts are the hydrothermal stability and higher nox activity within the temperature window of 150 to 600 oc [24]. cu-zeolites based scr catalysts have good performance even at low temperatures and it is also less sensitive on activity because of the no2 concentration variations [19]. however, cu zeolites are recognized for their higher sensitivity towards sulfur than the vanadium-based catalysts [25]. a mfi framework of cu/zsm-5 was first discovered in 1986, as an effective catalyst used for scr system [26]. currently, keen interest is showed towards catalyst structure based on the small pores; with special focus on the cu/sapo-34 and on cu/ssz-13. both catalysts have chabazite type structure but the composition of elements is different. while cu/sapo-34 ghazanfar mehdi (et al.), review on scr catalysts by focusing impacts of sulfur on scr performance (pp. 27 44) sukkur iba journal of emerging technologies sjet | volume 2 no. 1 january – june 2019 © sukkur iba university 31 is silicoaluminoposphates and cu/ssz-13 are zeolites [27]. while comparing the small pore structure of zeolites catalyst with the structure of larger pore, the structure with small pores has been observed more hydrothermally stable. besides a very high nox activity and selectivity can be achieved. furthermore, less amount of by products such as n2o can be formed during operating temperature range [27] and also it is less vulnerable for hydrocarbon poisoning [19]. while the comparing of cu/sapo-34 and cu/ssz-13, it was observed that cu/sapo34 has been more hydrothermal stable rather than cu/ssz-13 [26]. a number of catalysts proved to be suitable in favor of scr reactions. the most important proper components are transit oxides of metal, although al2o3, zeolite, tio2, sio2 and carbon are frequently used table i. summarized description of main scr catalysts type of catalysts proper components carrier advantages disadvantages ref: commercial catalyst based on vanadium titanium v2o5 tio2 so2 resistance is high, scr activity at high and low temperature oxidation of so2 [28-30] noble metals sn, ag, etc. tio2, al2o3 etc. h2o and so2 resistance is high; high low temperature scr activity narrow temperature window; high cost; generation of no2; ammonia oxidation [31, 32] oxides of metal v2o5, cuo, ceo2, mnox, coox, feox, and other composite oxide. tio2, al2o3etc. scr activity is high at 300-400 c; thermal stability is good; poisoning resistance is high poor activity at low temperatures [33, 34] zeolite mn, ce, fe, co, cu, cr, etc. zeolite wide temperature window hydrothermal stability is poor [35, 36] carbon catalyst v2o5, ceo2, mnox, etc. active carbon, active carbon filter, carbon nanotubes easy regeneration, specific surface area is large, chemical stability is high, high low temperature activity poor so2 resistance; energy consumption is high; frequent regeneration. [37, 38] like carriers. all catalysts have possessed different advantages and disadvantages and denox properties, which have been described in table. 2. 3.3. catalayst deactivation the selectivity and activity loss of catalyst over time is known as catalyst deactivation. mostly there are three mechanisms for the deactivation of scr catalysts named as thermal, chemical and mechanical. these mechanisms of catalyst decay can be further elaborated into six submechanisms where thermal decay by thermal deprivation such as fouling, sintering and poisoning. chemical decay can happen due to ghazanfar mehdi (et al.), review on scr catalysts by focusing impacts of sulfur on scr performance (pp. 27 44) sukkur iba journal of emerging technologies sjet | volume 2 no. 1 january – june 2019 © sukkur iba university 32 vapor formation, solid-solid reactions and poisoning. mechanical decay can occur through crushing or fouling. the most important mechanisms for catalyst deactivation are poisoning and fouling [39]. when poisoning is strong, gas-surface chemisorptions happen on catalyst surface; hence, as a result, it blocks the sites for catalyst reaction. poisoning of species depends upon the adsorption strength of species. the poisoning of species is either produced due to the change in the electronic or geometrical structure of surface or it just blocks the adsorption sites physically. the poisoning of species can be slow or fast, it mostly depending upon the concentration of poison. it can be irreversible or reversible depends upon the adsorption strength of poison [39]. fouling is due to deposition of species physically produced from fluid phase over the catalyst pores and in the catalytic surface. this is responsible for the blockage of pores and sites, which ultimately result in the loss of activity of catalyst [39]. 4. sulfur poisoning of scr catalsyts deactivation of scr catalyst occurs by different mechanisms; however, the most significant mechanism is sulfur poisoning. the important factor that influences the sulfur poisoning is the type of catalyst material. some are more and some are less sulphur tolerant depending on the catalyst materials. reaction temperature and availability of ammonia is also significant parameter for sulfur poisoning. therefore, it is necessary to investigate how sulfur behaves with scr catalysts. although many studies have been done on sulfur poisoning of catalysts, still it requires complete understanding. this review covers the sulfur poisoning of vanadium-based catalyst and cu-zeolites scr catalysts with mainly focus on cu-zeolites because of its sulfur sensitivity. many studies present in this review are to investigate the impact of sulfur on scr activity by accelerating the lab aging in flow reactors. the accelerated aging in lab has been carried out by using the different catalysts for sulfur under different conditions. there are different sulfation methods named as so2 exposure in the presence of ammonia, so2 exposure under different scr conditions or so3 exposure at different temperature ranges. few studies also related to the investigation of sulfur poisoning through experimental setup by using fuel with high sulfur contents. the experimental setup which is mostly used to investigate the sulfur 4.1. sulfur in exhaust gases the main source of sulfur at the diesel exhaust is originated from the engine lubricating oil and the presence of sulfur contents in the fuel [40]. throughout the last few years, contents of sulfur present in diesel fuel decreased extensively. hence, as a result, so2 level reduced in the atmosphere and also to avoid the use of highly efficient aftertreatment system at the diesel exhaust which is more sulfur sensitive. today, in north america and europe ultra-low sulfur diesel (ulsd) fuel is used which contains sulfur contents less than 10-15 ppm [41]. at diesel exhaust, sulfur oxides (sox) concentration depends upon the air fuel ratio and contents of sulfur present in the diesel fuel, this relation is represented in fig 4 [42]. sulfur is mostly in the form of so2 at the exhaust of diesel engine. it can be further oxidized into so3 when the scr system is located beyond the diesel oxidation catalyst (doc) [40]. 4.2. scr operated on heavy fuel oil (hfo) heavy fuel oil (hfo) is well known for its challenges and disadvantages related to scr system because it contains high sulfur contents in the diesel fuel. therefore, it allows the oxidation of so2 to so3 during the scr reaction. it is responsible for the formation of white plumes and ammonium bi sulfate (abs). furthermore, with the use of hfo the natural contents of vanadiumbased catalysts result in the prominent oxidation of so2. therefore, at present it is ghazanfar mehdi (et al.), review on scr catalysts by focusing impacts of sulfur on scr performance (pp. 27 44) sukkur iba journal of emerging technologies sjet | volume 2 no. 1 january – june 2019 © sukkur iba university 33 necessary to design the scr system in a way that resists the unwanted side reactions. fig. 4. relation in between the contents of sulfur in the diesel fuel and sox concentration at diesel exhaust for three air to fuel ratio in two-stroke diesel engines, because of the high energy efficiency, the temperature of gases at the diesel exhaust is low after the turbocharger. it is in between of the 230260 °c depending upon the load of the diesel engine. low temperature at diesel exhaust creates problem for the scr system when the hfo is used in the diesel engine. hence, in order to get the high fuel flexibility, the main precedence of diesel engine is to produce the exhaust gases with suitable temperature window, which ultimately results in improving the scr system. the exhaust gas temperature around 330 to 350°c should be ideal during the working of engine on hfo [43]. 4.3. formation of ammonium sulfates ammonium sulfates are produced when the exhaust temperature is low during the scr catalyst reaction in the presence of nh3 and sox as shown in reactions below: 𝑁𝐻3+ 𝑆𝑂3 + 𝐻2𝑂 → 𝑁𝐻4𝐻𝑆𝑂4 (1) 2𝑁𝐻3+ 𝑆𝑂3 + 𝐻2𝑂 → (𝑁𝐻4)2𝑆𝑂4 (2) 𝐻2𝑆𝑂4 + 𝑁𝐻3 →𝑁𝐻4𝐻𝑆𝑂4 (3) 𝑆𝑂3 + 𝐻2𝑂 →𝐻2𝑆𝑂4 (4) ammonium bisulfate (abs), nh4hso4 and ammonium sulfate (nh4)2so4 are responsible for the physical blockage of pores and channels of catalyst. therefore, the result in the deactivation of catalyst. abs is the most hazardous of all the species [44]. abs is generally formed, when the temperature is in between 190-240 ⁰c and it starts to decompose when temperature goes around 350 ⁰c [45]. the (nh4)2so4 decomposition occurs in two stages, first it decomposed into nh3 and nh4hso4 at about temperature of 300 ⁰c as represented in reaction 5. second, nh4hso4 will start decomposing when the temperature reaches at higher level as shown in reaction 6 [46]. (𝑁𝐻4)2𝑆𝑂4 (s) ↔ 𝑁𝐻4𝐻𝑆𝑂4 (s) + 𝑁𝐻3 (g) (5) 𝑁𝐻4𝐻𝑆𝑂4 (s) ↔ 𝑁𝐻3 (g) + 𝑆𝑂2 (g) + 1/2o2 (g) + 𝐻2𝑂 (g) (6) 4.4. impacts of sulfur on vanadium based scr catalyst many authors have proved that, vanadiumbased catalysts are operated at relatively narrow temperature range (300–400 °c) of scr system [47, 48]. if the operating temperature goes below to the 320 °c, the sulfur poisoning, specially poisoning of so2 becomes more imperative and the selectivity and activity of the scr catalysts decreases, significantly. furthermore, when the temperature goes above to the 400 °c, undesirable side reactions can occur which are responsible to produce n2o and no from the oxidation of nh3 [49]. nox removal efficiency is decreased progressively by means of catalyst aging. presence of so2 can cause the deactivation of scr catalysts during the scr operation. inhibition of so2 is the most common problem during the activity of catalyst [47, 50, 51]. following poisoning mechanism of so2 is imagined when nh3‐scr process is used. on the catalyst surface, so2 can be oxidized into so3. the produced so3 reacts with nh3 to generate the unwanted reactions such as (nh4)2so4 and nh4hso4. these two generated undesirable substances deposit in the pores of scr catalyst, which deactivate ghazanfar mehdi (et al.), review on scr catalysts by focusing impacts of sulfur on scr performance (pp. 27 44) sukkur iba journal of emerging technologies sjet | volume 2 no. 1 january – june 2019 © sukkur iba university 34 and block the active sites and cause the rapid decrease in the catalyst surface area [52]. the conversion rate of so2 is vary from 1%– 2% during the normal operating conditions of scr system [53]. many studies have proved that, in vanadium-based catalyst v=o bond shows the important role in the oxidation of so2 [54]. thus, the content of v2o5 is generally set to be smaller in the scr catalyst in order to avoid the generation of so3. water vapors appear in the flue gases and can be condensed on the surface of catalyst. it not only produces the exacerbate poisoning by the alkali metals like na and k, but also responsible for the vaporization and swelling with the increase of temperature. it damages the structure of catalyst, hence in result scr catalyst is cracked. it has been reported that for the physical adsorption water vapor is to compete with nh3 and no on the surface of catalyst, by this means denox activity of catalyst decreased [55]. the alkali metals such as (na, k) available in fly ash also disgrace the performance of catalyst when they deposited in the catalysts. therefore, lengthy acquisition can block pores, which results the poisoning of catalyst [51]. 4.5. impact of sulfur on cu-zeolite scr catalyst cu-zeolites are the more sulfur sensitive than vanadium-based catalysts. in this review catalysts with small pores such as cu/ssz-13 and cu/sapo-34 belong to chabazite family are concerned. the exposure of so2, so3 and/or so2 + nh3, so2 are investigated at different conditions of sulfur poisoning, also by considering the impact of temperature simultaneously. 4.5.1. impact of sulfur on scr chemical reactions the different scr reactions have different impact on the sulfur poisoning of cu-zeolites catalysts. standard scr reaction is much affected than the fast scr reaction [56, 57]. furthermore, at low temperatures catalyst activity is severely impacted than the catalyst activity at high temperatures [58]. 4.5.2. so2 impact on scr catalyst activity many studies have shown the deactivation of cu-zeolites catalyst under the so2 exposure and absence of nh3. it was reported that at different temperatures, the poisoning of catalyst is different. the so2 exposure of unspecified cu-zeolite has been reported high deactivation of catalyst at 200 °c as compared with 300 °c. overall least deactivation has been found at 400 °c after the exposure of so2 [58]. cu/ssz-13 also showed the same trend as above [22], catalyst was more deactivated at 250 °c as compared to 400 °c after poisoning. but the cu/sapo34 showed the opposite trend than the cu/ssz-13, it has been reported that cu/sapo-34 was more deactivated at 250 °c than the 150 °c after sulfation [59]. also it has been shown that the cu/sapo-34 was more deactivated at 400 °c as compared to 200 °c after the so2 exposure [57]. 4.5.3. so2 + nh3 impact on scr catalyst activity a comparative study between sulfation and with or without the presence of ammonia reported that, with the presence of nh3 at the temperature of 300 °c after sulfation, more deactivation of catalyst was found [56]. also, the same trend has been shown in another study [57], at temperature 400 °c during the presence of nh3, poisoning of sox produced the more negative affect as compared to the poisoning of sox without the use of nh3. 4.5.4. so2 and/or so3 impact on scr catalyst activity so3 poisoning has produced more significant impact of deactivation as compared with so2 poisoning. unspecified cu-zeolites was used to investigate the impact of poisoning temperature. with the increase of poisoning temperature (200, 300, 400 °c) more deactivation has been reported [60]. also, at the same temperature conditions, the impact of so2 as compared with so3 was investigated. it has been reported that poisoning of so3 resulted more significant deactivation than the so2 poisoning for all temperature ranges. ghazanfar mehdi (et al.), review on scr catalysts by focusing impacts of sulfur on scr performance (pp. 27 44) sukkur iba journal of emerging technologies sjet | volume 2 no. 1 january – june 2019 © sukkur iba university 35 during the investigation of cu/sapo-34 catalyst it has been observed that for so3 poisoning temperature was an important parameter [61]. poisoning of so2 and so2 + so3 at temperature of 200 °c both has same impact on the catalyst activity. however, so2 + so3 poisoning at temperature of 400 °c was responsible for the severe deactivation of catalyst than the so2 poisoning. it has been reported that the mechanism for the poisoning of so2 and so3 was different, whereas poisoning of so2 is due to the adsorption and poisoning of s03 is because of chemical reactions having activated temperature with catalyst surface. cu-zeolite catalyst associated with poisoning of sulfur was studied by putting 35 ppm of so2 in a “diesel system simulator” (dss). it consists of diesel oxidation catalyst (doc) at the upstream of catalyst soot filter (csf) and followed by scr system. since the scr reactor was located after the doc, therefore some part of so2 oxidized into s03. it has been proved that after the 400 hours the activity of scr reactor started to lose, which was about 4g of sulfur/litre [62]. 4.5.5. sulfur storage on cu-zeolites many papers have been reported the storage of sulfur on cu-zeolite and the poisoning of so2. it has been observed that different temperatures have different impact on sulfur storage. a cu/sapo-34 [59] and unspecified cu-chabazite [57] catalysts with chabazite structure were studied by considering the sulfur storage on catalysts. it has been reported in both investigations that exposure of so2 at high temperatures first at (350 ⁰c vs 190 ⁰c) and later at (250 ⁰c vs 150 ⁰c) showed sulfur storage in large amount. in another study [58] unspecified cu-zeolite showed the opposite trend, where exposure of so3 at low sulfation temperature (setting temperature for results: 200 ⁰c, 300 ⁰c and 400 ⁰c) reported large amount of sulfur storage. however, it has also been investigated in same study; the catalyst activity showed the larger decline at high temperatures after the sulfation. it was investigated that sulfur storage impacted with the different forms of sulfur [57, 58] both reported that the sulfur storage as a result of so3 exposure is more than so2 exposure. also, it has been observed that during sulfation period, the sulfur storage at the present of nh3 is more affected than the absence of nh3 [56, 59, 63]. fig.5. sox released during tpd on four different sulfur saturated chabazite structure scr catalysts. sulfur saturation of so2 and so3 was shown by solid lines and only so2 by dotted lines. at the temperature of 190 ⁰c and 350 ⁰c, blue and red lines were sulfur saturated respectively temperature programmed desorption (tpd) was used to investigate the sulfur storage on the four different sulfur saturated chabazite structure scr catalysts. fig. 5 showed the tpd diagram. sulfur saturation of so2 and so3 was shown by solid lines and only so2 by dotted lines. at the temperature of 190 ⁰c and 350 ⁰c, blue and red lines were sulfur saturated respectively. at doc, so2 was oxidized into so3, therefore the ratio of so3 and so2 largely depends upon the sulfation temperature. at high sulfation temperatures, significant amount of so3 can be estimated. two peaks have been shown in all tpd curves first at ca 480 ⁰c and second at ca 650 ⁰c. it has been concluded that for both so3 and so2, sulfur storage was much more after sulfation as compared to only so2. furthermore, at high temperature (350 ⁰c), more sulfur storage occurs after sulfation than the low temperature (190 ⁰c) [57]. ghazanfar mehdi (et al.), review on scr catalysts by focusing impacts of sulfur on scr performance (pp. 27 44) sukkur iba journal of emerging technologies sjet | volume 2 no. 1 january – june 2019 © sukkur iba university 36 4.5.6. regeneration of sulfated cu-zeolite it has been reported that different type of ways showed different results while regenerating the sulfated cu-zeolites. sulfation of 200 ppm of so2 at 130 ⁰c for 3 hours was carried out to regenerate the cu/sapo-34 catalyst [46]. regeneration of a cu/sapo-34 catalyst was performed for 12 hours by varying temperatures at 300, 400, 500, 600 and 700 ⁰c. up to temperature of 600 ⁰c, regenerated catalyst showed the limited recovery in no removal efficiency. the regeneration of catalyst was fully observed at 600 ⁰c. various sulfation methods were used to investigate the regeneration of cu-chabazite catalyst [57]. it has been observed that the regeneration of so2 aged catalyst at low temperature (200 ⁰c) was easier than the high temperature (400 ⁰c) aged. furthermore, during the comparison of so2 aged catalyst, with and without the presence of nh3, no difference has been observed in the regeneration of catalyst. a repeated activity test has been performed for the regeneration of cu/ssz-13 catalyst at temperatures in between of 100 ⁰c to 400 ⁰c [56]. catalyst with exposure of s02 poisoning (30 ppm) was investigated at temperature of 300 ⁰c for 1.5 hours. eight activity tests have been performed to obtain the stable activity. it has been observed from the experiment that by repeating the activity test some activity was recovered but not achieving the fully regeneration of catalyst. cu-chabazite catalyst was used to investigate the regeneration also named as chemical desox method [21]. for reducing the environmental problems, low concentration of reductant such as nh3, nox+nh3, c2h6 and n-c12h26 was used. by using this technique, it has been observed that at lower regeneration temperatures, recovery of nox conversion activity and removal of sulfur was achieved. 4.5.7. characterizations of sulfated cuzeolites sulfated catalyst has been characterized in many studies. n2 adsorption is used to determine to surface area and its pore volume. it has been observed that after the sulfation both surface area and pore volume were decreased [20-22, 56]. but after regeneration both could be recovered [22]. xray flouorescence (xrf) was used to investigate the framework of sapo-34 and it has been observed that it was not changed after the poisoning of so2. this recommends that sulfur only affects the copper sites of catalyst not the framework of zeolite [64]. analysis of inductively coupled plasma (icp) and x-ray photoelectron spectroscopy (xps) were used to investigate the sulfur distribution, it has been found that, sulfur was uniformly distributed only if the catalyst was saturated [57, 61]. more sulfur has been observed at the catalyst inlet as compared to outlet, if the catalyst was not saturated properly [56, 58]. numerous methods have been reported to determine the type in which storage of sulfur is taken place over the sulfated cu-zeolite. it has been observed that there are two primary sulfur species such as ammonium sulfates and copper sulfates depending upon the sulfation conditions [46, 58, 59]. formation of ammonium and copper sulfates was studied on the cu/sapo-34 catalyst [65]. it has been observed that ammonium and copper sulfates are exchangeable depends upon the availability of nh3. ammonium sulfates can be formed by nh3 exposure of copper sulfates over the catalyst. during the absence of nh3 the usage of ammonium sulfates upon the no exposure behaves as scr reactant. however, this reaction is much slow as compared to normal scr reaction. also, copper sulfates are formed when the scr reactants are ammonium sulfates. ghazanfar mehdi (et al.), review on scr catalysts by focusing impacts of sulfur on scr performance (pp. 27 44) sukkur iba journal of emerging technologies sjet | volume 2 no. 1 january – june 2019 © sukkur iba university 37 4.5.8. sulfur posioning mechanism on cuzeolite cu/ssz-13 catalyst was used to investigate the active sites. diffuse reflectance infrared fourier transform spectroscopy (drifts) with nh3 probing was used to identify the two cu-sites. in scr reactions both sites were active but in oxidation reactions only one site was active. furthermore, also their responses towards sulfur poisoning and hydrothermal aging were investigated. in oxidation reaction the active site was disappeared and in scr reaction, both active site was reduced extensively [66]. after so2 poisoning, the activity loss over the cu/sapo-34 catalyst was described by the reduction in the active sites of cu-zeolite because of the sulfur present in the catalyst. it has been observed that the no conversion and sulfur exposure showed inverse relationship if sulfur exposure was increased then no conversion was decreased [64]. 4.6. behavior of sulfur over scr catalysts with different temperatures (recent developments) so2 poisoning of nh3-scr was evaluated by yasser [67] over cu-sapo-34, mainly to investigate stored s forms/states and the effect of them on reduction activity of low-temperature nox. there were two types of primary sulfur species found, and it was observed that they both were interchangeable depending upon the availability or the absence of nh3. cu sulfate species as well as ammonium sulfate species could be found in one case, while for the other case only cu sulfate species would be found. cu sulfate was available in three different states/forms when ammonia was absent, this was found out by three desorption features while conducting experiments of tpd (temperature programmed desorption). no adsorption’s drifts (diffuse reflectance infrared fourier transform spectroscopy) was utilized for the investigation of accessibility and nature of cu species prior to and after the sulfate formation, subject to no intrusion by ammonium sulfate; the acquired states showed that the sulfur had completely blocked cu2+ within the six membered rings, and nature of [cuoh]+ near the eightmembered ring had changed. on analyzing impacts of dissimilar states of s on reduction activity of nox, ammonium sulfate having low-temperature was found to have the greatest effect on the loss of performance. moreover, the data demonstrated that ammonium sulfate have tendency to work as scr reactant, quite similar to the system incorporating ammonium nitrate. decomposition of ammonium sulfate starts at temperatures which can be as small as 300−350 °c, in contrast to that higher temperatures (>480 °c) were required for desorption of other s containing species as illustrated in fig 6. fig. 6. scr changing at 210 °c along with the raw sample, during existence of so2 quantity50 ppm, sample on which cuxsoy was materialized and later brought to temperatures of 430, 530, 630, 730, and 830 °c in presence of (nh4)x or n2 this seems promising, as reaction of nh3 can occur in the presence of catalyst with reabsorbed sulfur to form ammonium sulfate, having tendency to decompose at smaller temperatures as compared to other forms of sulfate. sandra [68] observed the impacts of sulphur experimentally, upon lowtemperature behavior of cu-ssz-13 scr catalyst. the outcomes of exposure ghazanfar mehdi (et al.), review on scr catalysts by focusing impacts of sulfur on scr performance (pp. 27 44) sukkur iba journal of emerging technologies sjet | volume 2 no. 1 january – june 2019 © sukkur iba university 38 temperature of sulfur, and impacts of nox/no2 ratio, are taken into consideration and a comparison of two separate regeneration temperatures is performed. besides that, samples of catalyst taken from catalyst affected by an engine-aged are analyzed. exposition temperature of so2 possesses important effect on cu-ssz-13 catalyst deactivation. the most severe deactivation is caused due to lowest sulphur exposure temperature (220 °c), whereas during the highest temperature of sulphur exposure (400 °c) deactivation of the lowest degree is observed as demonstrated in figure 7. yulong [69] investigated the hydrothermal aging at prominent temperature. not the same as the reversible hindrance of so2 harming that happens at truncated temperatures, because of the demolition of the zeolite structure the sulfur harming at prominent temperature is longlasting. fig. 7. relative rate constants for catalyst exposed at different temperature ranges. note that, the sample which was brought at 220 °c to so2 had no test at 280 °c.5vol.-% h2o,10 vol.-% o2 1000 vol.-ppm nh3, 1000 vol.-ppm no, 120,000 h−1ghsvduring the test of activity. in figure 8 the benchmark scr nox and nh3 transformation exercises of ha-cussz-13, fr-cu-ssz-13 and sa-cu-ssz-13 chemical agents are portrayed by means of a portion of temperature as of 150 to 550 °c. it has been observed the new cu-ssz-13 showed the finest nh3-scr action on entire temperature ranges. the decrease action of no weakened somewhat for the cu-ssz-13 afterwards it was hydrothermally aged at 750 °c aimed at 32h. for the sa-cu-ssz-13 test critical loss of not any decreased movement was watched that was hydrothermally aged within the sight of 100 ppm so2.throughout hydrothermal aging proposed deactivation of cu-ssz-13 was significantly more extreme within the sight of so2. the nh3 change is a lot advanced than any transformation due to unselective nh3 oxidation. when the temperatures over 450 °c and 300 °c aimed at the sa-cu-ssz-13 and ha-cu-ssz-13 tests, the uncritical nh3 oxidation was fundamentally in charge for the decomposition of not any adaptation at prominent temperatures. meiqing [70] investigated the impact of so3 poisoning over cu/sapo-34. fig. 8. no and nh3 =500 ppm, 5 vol. %o2, 5 vol. % h2o, equilibrium n2. ghsv =400,000 h-1. nox and nh3 change of ha-cu-ssz-13, fr-cussz-13 and sa-cu-ssz-13 catalysts below normal scr circumstances. fig. 9 the reaction of nh3 scr consisting sulfated and fresh cu/sapo-34 catalysts is shown. in comparison to f-cu, declines in nox conversion are seen of sulfated catalysts when so3 to sox ratio increases. remarkably, throughout the whole temperature region, s-20-cu was found to be least active catalyst of all kinds of sulfated samples. unsulfured catalysts having 600 c (7 ppm) has the highest n2o formation on it, and the sulfation action results in reduction of the formation of n2o by 1 to 2 ppm. (fig. 8b). ghazanfar mehdi (et al.), review on scr catalysts by focusing impacts of sulfur on scr performance (pp. 27 44) sukkur iba journal of emerging technologies sjet | volume 2 no. 1 january – june 2019 © sukkur iba university 39 in this work [71] the deactivation conducts and procedure of a cu-sapo-34 catalyst by reactor trial and dft computations was studied. the dignified steady state of nox changes for the new catalyst can be determined from the figure 1a, after introduction to so2, and subsequently regeneration at 550 °c. after introduction of so2, 1.5 ppm portion was added to the scr-feed, so2 concentration is also presumed in automotive diesel exhaust, for 8h we detained the new catalyst at 300 °c, execution at 550 °c for 1 h in scr-feed gas in the absence of so2 for renewal of the catalyst. when so2 was introduced it resulted in significantly lesser steady state nox changes in the temperature variety 150–300 °c. for all intents and practical purposes after probing so2 deactivation, it is frequently convenient towards quicken the so2-harming by rising the concentration of so2 and proportionally abbreviating the exposure period. the outcomes are then construed in appellation of the overall so2 exposure, considered as the formation of the so2 fractional pressure and the exposure period, instead of the so2 concentration. this elucidation needs that a straight proportionality occurs and the exposure period and so2 concentration, in a way that dual framework can be climbed with respect to so2-harming. by estimating the outcomes of the non-accelerated so2 introduction scalability was scrutinized for example introduction to 1.5 ppm so2, towards the outcomes from a catalyst revealed to an enhanced so2 introduction. meant for the enhanced so2 introduction, the concentration of so2 was enlarged by a number 10 and the introduction time was harmoniously reduced. fig. 9. nox conversion as a relation pertaining to reaction temperature on the raw and sulfated catalysts s-0-cu = 50 ppm of so2 for 16h, s-6-cu = 50 ppm of sox (6% so3) for 16h, s-13-cu = 50 ppm of sox (13% so3) for 16h and s-20-cu 50 ppm of sox (20% so3) for 16h (a) and emergence of n2o in course of nh3 scr reaction over the fresh and sulfated catalysts (b)the execution of reaction was done with a mixture containing nox 500 ppm, nh3500 ppm, 7% co2, 5% o2, 3% h2o, and balance n2 owing to ghsv = 72,000 h-1 ghazanfar mehdi (et al.), review on scr catalysts by focusing impacts of sulfur on scr performance (pp. 27 44) sukkur iba journal of emerging technologies sjet | volume 2 no. 1 january – june 2019 © sukkur iba university 40 fig. 10(a) nox as purpose of temperature exhibits its conversion for the cu-sapo-34 catalyst earlier and later experience to 1.5ppm (b) the temperature for the cu-sapo-34 by nox conversion catalyst earlier and later exposure to 15 ppm (c) after deactivation the sulfated (blue inns) and recovered (red inns) express the cu-sapo-34 catalysts assessed at 180 °c, afterwards introduction to 1.5 ppm so2 aimed at 8h and 15 ppm so2 aimed at 48 min. therefore, in the so2 in scr-feed gas was exposed to 15 ppm for 48 min at 300 °c. figure10b illustrates the stable state of nox changes earlier and later the accelerated so2 exposure, and later 1 h renewal at 550 °c inside scr-feed gas. the outward form of the nox changes is for the enhanced so2 introduced catalyst in fig. 10b, it is very analogous to the revealed inside figure10a, figure10b. illustrates the nox vicissitudes of the new catalyst is somewhat underneath those of the new catalyst in figure 10a which is because of slight variances in the catalyst loads. hence, to check the resemblance of the impact of the enhanced and non-enhanced so2 exposure circumstances on the scr presentation of the catalyst, the deactivation (assessed at 180 °c) after so2 experience and renewal are illustrated in figure 10c. after both behaviors the degree of deactivation is similar with overall deactivations of 80 and 79% and permanent deactivations of 16% and 18%. for the same total exposure, it signifies that the deactivation is identical, here so2 concentration and revelation period are scalable. 5. summary vanadium based catalysts can be impacted by sulfur exposure in different ways. if nh3 is absence during poisoning at high temperatures, nox activity can be increased. if nh3 is present during the sulfur exposure of catalyst, formation of ammonium sulfates can be produced, which ultimately results the physical deactivation of catalyst. the decomposition of ammonium sulfates occurs when the temperature in between 280-350 ⁰c and also by increasing the temperature regeneration of catalyst can be achieved. consequently, the main problem occurs with vanadium-based catalyst when the high level of sulfur is exposed at low temperatures. thus, the catalyst temperature never exceeds the decomposition temperature. nox activity can be deactivated with sulfur exposure of cu-zeolites catalysts. so3 poisoning is capable to produce severe deactivation of catalyst activity, high sulfur storage and very hard to regenerate the catalyst as compared to so2 poisoning. so3 and so2 poisoning are not reliable with impact of temperature. it has been recommended that, at high temperature chemisorption occurs over the catalyst surface and at low temperature formation of ammonium sulfate and physical adsorption ghazanfar mehdi (et al.), review on scr catalysts by focusing impacts of sulfur on scr performance (pp. 27 44) sukkur iba journal of emerging technologies sjet | volume 2 no. 1 january – june 2019 © sukkur iba university 41 occurs. two sulfated species were observed while characterizing the sulfated cu-zeolite named as ammonium and copper sulfates. it has been recommended that sulfated species is the main cause of deactivation which ultimately blocks the active cu-sites, either by the formation of ammonium and copper sulfates that blocks the active sites of catalyst physically or by adsorption of sulfur species. furthermore, sulfur poisoning does not affect the zeolite structure, but it only affects the active sites of copper. sulfated catalysts have been regenerated in a lean environment by increasing exposure temperature about to 600-700 ⁰c. acknowledgement i would like to thank the national key r&d program of china (2016yfc0205200) and the ministry of industry and information technology of marine low-speed engine project phase – i for supporting this work. references [1] p. geng, “effects of alternative fuels on the combustion characteristics and emission products from diesel engines,” a review. renewable and sustainable energy reviews, vol. 71, 2017, pp. 523-534. [2] n. hu, p. zhou, and j. yang, “reducing emissions by optimising the fuel injector match with the combustion chamber geometry for a marine medium-speed diesel engine,” transportation research part d: transport and environment, vol. 53, 2017, pp. 1-16. [3] c. zhanga, c. suna, m. wua, and k. lub, “optimization design of scr mixer for improving deposit performance at low temperatures,” fuel vol. 237, 2019, pp. 465– 474. [4] w. chen, h. fali, l. qin, h. jun, b. zhao, t. yangzhe, and y. fei, “mechanism and performance of the scr of no with nh3 over sulfated sintered ore catalyst.” catalysts vol. 9, 2019, pp. 90-101. [5] c. baukal, “everything you need to know about nox: controlling and minimizing pollutant emissions is critical for meeting air quality regulations,” metal finishing, vol. 103, 2005, pp. 18-24. [6] gu, “a potentially over estimated compliance method for the emission control areas,” transportation research part d, vol. 55, 2017, pp. 51-66. [7] a. aberg, a. widd, j. abildskov, and j.k. huusom, “parameter estimation and analysis of an automotive heavy-duty scr catalyst model,” chemical engineering science, vol. 161, 2017, pp. 167–177. [8] e. codan, s. bernasconi, and h. born, imo iii emission regulation: impact on the turbocharging system, cimac congress, 2010. [9] r. geertsma, r. negenborn, k. visser, m. loonstijn, and j. hopman, “pitch control for ships with diesel mechanical and hybrid propulsion: modeling, validation and performance quantification,” applied energy, vol. 206, 2017, pp. 1609–1631. [10] l. xr, “combustion and emission characteristics of a lateral swirlcombustion system for di diesel engines under low excess air ratio conditions,” fuel, vol. 186, 2016, pp. 672-80. [11] c. k, p. j, and k. sl, “a comparison of reactivity controlled compression ignition (rcci) and gasoline compression ignition (gci) strategies at high load, low speed conditions,” energy convers manag, vol. 127, 2016, pp. 324-41. [12] a. güthenke, d. chatterjee, m. weibel, m. krutzsch, b. kocí, p. marek, m. nova, and e. tronconi, “current status of modeling lean exhaust gas aftertreatment catalysts’, advances in chemical engineering, vol. 33(07), 2007. [13] m. koebel, m. elsener, and m. kleemann, “urea-scr: a promising technique to reduce nox emissions from automotive diesel engines,” catalysis today, vol. 59(3/4), 2000, pp. 335-345. [14] oliveira, “modeling of nox emission factors from heavy and light-duty vehicles equipped with advanced after treatment systems,” energy conversion and management, vol. 52, 2011, pp. 2945-2951. [15] s.s. p, “a review on selective catalytic reduction (scr)-a promising technology to mitigate nox of modern automobiles,” international journal of applied engineering research, vol. 13, 2018, pp. 5-9. [16] f. birkhold, “modeling and simulation of the injection of urea-water solution for automotive scr denox-systems,” applied catalysis b: environmental, vol. 170, 2007, pp. 119-127. [17] c. choi, “numerical analysis of urea decomposition with static mixers in marine scr system,” journal of clean energy technologies, vol. 3(1), 2015, pp. 39-42. ghazanfar mehdi (et al.), review on scr catalysts by focusing impacts of sulfur on scr performance (pp. 27 44) sukkur iba journal of emerging technologies sjet | volume 2 no. 1 january – june 2019 © sukkur iba university 42 [18] y. xi, n. a. ottinger and g. liu, “new insights into sulfur poisoning on a vanadia scr catalyst under simulated diesel engine operating conditions,” applied catalysis b: environmental, vol. 64, 2014, pp. 1-9. [19] i. nova and e. tronconi, “urea-scr technology for denox after treatment of diesel exhausts,” springer, 2014. [20] b. k. yun, and m.y. kim, “modeling the selective catalytic reduction of nox by ammonia over a vanadium-based catalyst from heavy duty diesel exhaust gases,” applied thermal engineering, vol. 50, 2013, pp. 152-158. [21] h. l. fang, h.f.m, and dacosta, “urea thermolysis and nox reduction with and without scr catalysts.” appl. catal. b: environ, vol. 46, 2013, pp. 14-34. [22] x. liu, x. wu, d. weng and z. si, “durability of cu/sapo-34 catalyst for nox reduction by ammonia: potassium and sulfur poisoning,” catalysis communications, vol. 59, 2014, pp. 35-39. [23] a. kumar, m. a. smith, k. kamasamudram, n. w. currier and y. aleksey, “chemical desox: an effective way to recover cuzeolite scr catalysts from sulfur poisoning,” catalysis today, vol. 267, 2016, pp. 10-16. [24] d. w. brookshear, j.-g. nam, k. nguyen, t. j. toops and a. binder, “impact of sulfation and desulfation on nox reduction using cuchabazite scr catalysts,” catalysis today, vol. 258, 2015, pp. 359-366. [25] d. chatterjee and k. rusch, “urea-scr technology for denox after treatment of diesel exhausts,” springer, 2014. [26] j. wang, h. zhao, g. haller and y. li, “recent advances in the selective catalytic reduction of nox with nh3 on cu-chabazite catalysts,” applied catalysis b: environmental, vol. 202, 2017, pp. 346-354. [27] k. leistner, o. mihai, k. wijayanti, a. kumar, k. kamasamudram, n. w. currier, a. yezerets and l. olsson, “comparison of cu/bea, cu/ssz-13 and cu/sapo-34 for ammonia-scr reactions,” catalysis today, vol. 258, 2015, pp. 49-55. [28] y. peng, et al., “comparison of moo3 and wo3 on arsenic poisoning v2o5/tio2 catalyst: drifts and dft study,” applied catalysis. b, vol. 181, 2016, pp. 692-698. [29] s. m. lee, k.h. park, and s.c. hong, mnox/ceo2–tio2 mixed oxide catalysts for the selective catalytic reduction of no with nh3 at low temperature,” chemical engineering journal, vol. 13, 2012, pp. 323331. [30] y. qiu, et al., “the monolithic cordierite supported v2o5–moo3/tio2catalyst for nh3-scr.,” chemical engineering journal, vol. 294, 2016, pp. 264-272. [31] m. shimokawabe, “scr of no by dme over al2o3 based catalysts: influence of noble metals and ba additive on lowtemperature activity,” catalysis today, vol. 164, pp. 480-483. [32] s. s. kim, “enhanced catalytic activity of pt/al2o3 on the ch4 scr,” journal of industrial and engineering chemistry, vol. 18, 2012, pp. 272-276. [33] l.m. yu, et al., “enhanced nox removal performance of amorphous ce-ti catalyst by hydrogen pretreatment. journal of molecular,” catalysis a, vol. 423, 2016, pp. 371-378. [34] x. liu, et al., “probing nh3-scr catalytic activity and so2 resistance over aqueousphase synthesized ce-w@tio2 catalyst,” journal of fuel chemistry and technology, vol. 44, 2016, pp. 225-231. [35] c. k. seo, et al., “effect of zro2 addition on de-nox performance of cu-zsm-5 for scr catalyst,” chemical engineering journal, vol. 191, 2012, pp. 331-340. [36] p. nakhostinpanahi, “comparative study of zsm‐5 supported transition metal (cu, mn, co, and fe) nanocatalysts in the selective catalytic reduction of no with nh3,” environmental progress and sustainable energy, vol. 36, 2017, pp. 1049-1055. [37] x. l. tang, et al., “low-temperature scr of no with nh3 over ac/c supported manganese-based monolithic catalysts,” catalysis today, vol. 126, 2007, pp. 406411. [38] b. c. huang, et al., “low temperature scr of no with nh3 over carbon nanotubes supported vanadium oxides,” catalysis today, vol. 126, 2007, pp. 279-283. [39] c. h. bartholomew, “mechanisms of catalyst deactivation,” applied catalysis a: general, vol. 212, 2001. pp. 1760. [40] m. v. twigg, “progress and future challenges in controlling automotive exhaust gas emissions,” applied catalysis b: environmental, vol. 70, 2007, pp. 2-15. [41] a. varna, a.c. spiteri, and y.m. wright, “experimental and numerical assessment of impingement and mixing of urea-water sprays for nitric oxide reduction in diesel exhaust,” applied energy, vol. 157, 2015, pp. 824-837. [42] s. grout, j.b. blaisot, and k. pajot, “experimental investigation on the injection of an urea-watersolution in hot air stream for the scr application: evaporation and spray/wall interaction,” fuel, vol. 106, 2013, pp. 166-177. ghazanfar mehdi (et al.), review on scr catalysts by focusing impacts of sulfur on scr performance (pp. 27 44) sukkur iba journal of emerging technologies sjet | volume 2 no. 1 january – june 2019 © sukkur iba university 43 [43] man b&w. man emission project guide: man b&w two-stroke marine engines. eu: man b&w press 2013. [44] r. m. heck, r. j. farrauto and s. t. gulati, catalytic air pollution control commercial technology, 3ed., new yersey: john wiley & sons, inc., 2009. [45] y. h. shi, h. shu, y.-h. zhang, h.-m. fan, y.-p. zhang and l.-j. yang, “formation and decomposition of nh4hso4 during selective catalytic reduction of no with nh3 over v2o5-wo3/tio2 catalysts,” fuel processing technology, vol. 150, 2016, pp. 141-147. [46] l. zhang, d. wang, y. liu, k. kamasamudram, j. li and w. epling, “so2 poisoning impact on the nh3-scr reaction over a commercial cu-sapo-34 scr catalyst,” applied catalysis b: environmental, vol. 157, 2014, pp. 371-377. [47] r. q. long, r. t. yang and r. chang, “low temperature selective catalytic reduction (scr) of no with nh3 over fe–mn based catalysts,” chem. communication, vol. 5, 2012, pp. 452–453. [48] w. t. mu, j. zhu, s. zhang, y. y. guo, l. q. su, x. y. li and z. li, “styrene hydrogenation performance of pt nanoparticles with controlled size prepared by atomic layer deposition,” catal. sci.technol, vol. 6,2016, pp. 7532-7548. [49] c. u. i. odenbrand, “urea-scr technology for denox after treatment of diesel exhausts,” chem. eng. res. des, vol. 86, 2008, pp. 663–672. [50] j. p. chen, m. a. buzanowski, r. t. yang and j. e. cichanowicz, “deactivation of the vanadia catalyst in the selective catalytic reduction,” process air waste manage, vol. 40, 1990, pp. 1403–1409. [51] x. y. guo, [ms dissertation], brigham young university, 2006, pp. 25–28. [52] l. chmielarz, r. dziembaj, t. łojewski, a. wȩgrzyn, t. grzybek, j. klinik and d. olszewska, “deactivation of scr catalysts by exposure to aerosol particles of potassium and zinc salts,” solid state ionics, vol. 141, 2001, pp. 715–719. [53] c. orsenigo, a. beretta, p. forzatti, j. svachula, e. tronconi, f. bregani and a. baldacci, “theoretical and experimental study of the interaction between nox reduction and so2 oxidation over denox-scr catalysts,” catal. today, vol. 27, 1996, pp. 15–21. [54] p. d. ji, x. gao, x. s. du, c. h. zheng, z. y. luo and k. f. cen, “relationship between the molecular structure of v2o5/tio2 catalysts and the reactivity of so2 oxidation catal. sci.technol, vol. 6, 2015, pp. 1187–1194. [55] g. busca, l. lietti, g. ramis and f. berti, “characterization and reactivity of v2o5– moo3/tio2 de-nox scr catalysts” appl. catal. b, vol. 18, 1998, pp. 1–36. [56] k. wijayanti, k. leistner, s. chand, a. kumar, k. kamasamudram, n. w. currier, a. yezerets and l. olsson, “deactivation of cu-ssz-13 by so2 exposure under scr conditions,” catalysis science & technology, vol. 6, 2016, pp. 2565-2579. [57] a. kumar, j. li, j. luo, s. joshi, a. yezerets and k. kamasamudram, “catalyst sulfur poisoning and recovery behaviours: key for designing advanced emission control systems,” sae international, 2017. [58] y. cheng, c. lamberg, d. h. kim, j. h. kwak, s. j. cho and c. h. peden, “the different impacts of so2 and so3 on cu/zeolite scr catalysts,” catalysis today, vol. 151, 2010, pp. 266-270. [59] c. wang, j. wang, j. wang, t. yu, m. shen, w. wang and w. li, “the effect of sulfate species on the activity of nh3-scr over cu/sapo-34,” applied catalysis b: environmental, vol. 204, 2017, pp. 239-249. [60] y. cheng, c. montreuil, g. cavataio and c. lambert, “the effects of so2 and so3 poisoning on cu/zeolite scr catalysts,” sae international, dearborn, usa, 2009. [61] a. kumar, m. a. smith, k. kamasamudram, n. w. currier, h. an and a. yezerets, “impact of different forms of feed sulfur on small-pore cu-zeolite scr catalyst,” catalysis today, vol. 231, 2014, pp. 75-82. [62] w. tang, x. huang and s. kumar, “department of energy,” 04 october 2011. [online].available:https://energy.gov/sites/pr od/files/2014/03/f8/deer11_tang.pdf.[accesse d april 3 2017]. [63] y. jangjou, d. wang, kumar, ashok, j. li and w. s. epling, “so2 poisoning of the nh3-scr reaction over cu-sapo-34: effect of ammonium sulfate versus other scontaining species,” asc catalysis, vol. 6, 2016, pp. 6612-6622. [64] m. shen, h. wen, t. hao, t. yu, d. fan, j. wang, w. li and j. wang, “deactivation mechanism of so2 on cu/sapo-34 nh3scr catalysts: structure and active cu2+,” catalysis science & technology, vol. 5, 2015, pp. 1741-1749. [65] y. jangjou, d. wang, a. kumar, j. li and w. s. epling, “so3 posioning of the nh3-scr reaction over cu-sapo-34,” acs catalysis, vol. 6, 2016, pp. 6716-6728. [66] j. luo, d. wang, a. kumar, j. li, k. kamasamudram, n. currier and a. yezerets, ghazanfar mehdi (et al.), review on scr catalysts by focusing impacts of sulfur on scr performance (pp. 27 44) sukkur iba journal of emerging technologies sjet | volume 2 no. 1 january – june 2019 © sukkur iba university 44 “identification of two types of cu sites in cu/ssz-13 and their unique responses to hydrothermal aging and sulfur poisoning,” catalysis today, vol. 267, 2016, pp. 3-9. [67] y. jangjou, d. wang, a. kumar, j. li, and s. william, “so2 poisoning of the nh3-scr reaction over cu-sapo-34: effect of ammonium sulfate versus other s containing species,” acs catal, 6, 2016, pp. 6612−6622. [68] s. dahlina, c. lanttob, j. englund, b. westerbergd, f. regalid, m. skoglundhc, l. j. petterssona, “chemical aging of cu-ssz13 scr catalysts for heavy-duty vehicles – influence of sulfur dioxide,” catalysis today 320, 2019, pp. 72–83. [69] y. shan, x. shi, z. yan, j. liu, y. yu, h. he, “deactivation of cu-ssz-13 in the presence of so2 during hydrothermal aging,” catalysis today, 320, 2019, pp. 84–90. [70] m. shen, y. zhang, j. wang, c. wang, j. wang, “nature of so3 poisoning on cu/sapo-34 scr catalysts,” journal of catalysis, 358, 2018, pp. 277–286. [71] p. s. hammershoi, p. n.r. vennestrom, h. falsig, a. d. jensen, t. v.w. janssens, “importance of the cu oxidation state for the so2-poisoning of a cu-sapo-34 catalyst in the nh3-scr reaction,” applied catalysis b: environmental. 236, 2018, pp. 377–383. format template vol. 1, no. 2 | july december 2018 sjet | issn: 2616-7069 | vol. 1 | no. 2 | © 2018 sukkur iba 19 energy harvesting for water quality monitoring using floating sensor networks: a generic framework sarang karim1,mushtaque ahmed rahu2,ayaz ahmed3,azeem ayaz mirani4,ghullam murtaza jatoi1 abstract: water is a constrained asset and basic requirement for animals, cultivation and industry that exist on this earth including mankind. subsequently, to measure the characteristics like physical, biological and chemical attributes of water becomes indispensable. floating sensor networks (fsn) with in-situ sensors are now widely used to gather the water quality data. the main goal that deals with fsns is data reliability, congestion control, optimal node placement and energy. so far, we proposed a generic framework for energy harvesting, reliable data transform congestion detection and deployment strategy for fsn to collect water quality data. energy harvesting subsystem model will be designed to fulfil the needs for the desired application scenarios in sensor networks and extend the network lifetime. therefore, this model will help in scheduling the sending/receiving, sleeping and idle time of the node. by incorporating this framework, network lifetime can be prolonged. for reliable data transform and congestion detection; a model will be developed to enhance the data delivery. the objectives of optimal node deployment are full coverage, network connectivity, improve the data fidelity and enhance the network lifetime. keywords: wireless sensor networks; floating sensor network; water quality; energy harvesting; reliable data transfer. 1. introduction water is the greatest blessing of almighty allah, so it plays a pivotal role for the survival of all living things. so, by keeping its importance we should understand its optimized usage. if we look around our surroundings, we can find that most of the people are unable to have good and hygienic water for drinking. even most developed countries of the world are using filthy and 1 institute of ict, mehran university of engineering & technology, jamshoro, pakistan 2 department of electronic engineering, quaid-e-awam university of engineering, science & technology, nawabshah 3 department of es engineering, quaid-e-awam university college of engineering, science & technology, nawabshah 4 phd scholar, department of cse, quaid-e-awam university of engineering, science & technology, nawabshah corresponding author: sarangkarim@hotmail.com polluted water for in taking deprived of suitably treated. this condition happens due to shortage of water quality monitoring and treatment systems. there are various sensors available for the monitoring of water parameters, like ph, oxygen density, temperature, humidity, salinity and so on [1]. hence, for improving the water quality, its key parameters must be calculated before going towards quality sector. water quality parameters, like temperature, conductivity, mailto:sarangkarim@hotmail.com sarang karim (et al.), energy harvesting for water quality monitoring using floating sensor networks: a generic framework (pp. 1932) sukkur iba journal of emerging technologies sjet | volume 1 no. 2 july – december 2018 © sukkur iba university 20 turbidity, salinity, ph, dissolved oxygen and total dissolved solids are the most important parameters of water to be measured. as, we know that the quality of water totally relies on these parameters. once these parameters are calculated then it becomes much easier to work on water treatment procedures. the hasty and prompt advancement of technology in the field of wireless sensor network (wsn) has capability of developing a novel tool for data acquisition, environmental monitoring, wireless back-end transmission and so on in terms of real-time deployment and implementation. wireless sensor networks are composed of various tiny components called as nodes [2]. each node consists of desired sensors, memory, processor, radio frequency (rf) transceiver, antenna, etc. the wsn field is a broad field in terms of types and application scenarios [3, 4]. various types of wireless sensor networks are terrestrial wsns, underwater wsns, underground wsns, floating wsns; mobile wsns. wireless sensor network also seeks applications in water bodies by incorporating a new emerging field, so called as floating sensor networks (fsn) [5, 6]. floating sensor networks with in situ sensors are now widely used to gain the water quality data. floating sensor networks that take local measurements and water flows in water bodies and rivers are formally called as drifters [5-7]. so far, our focus is to propose a generic framework with reliable data transform and deployed in real time based on fsns to monitor the water quality parameters powered by harvested energy. many researchers have already worked on sensor networks-based water environmental monitoring with [8-10] and without [11-14] energy harvesting mechanisms [15-21] like, radio frequency (rf), solar, wind, thermal and flow. meanwhile, different researcher in the stateof-the-art have focused on reliable data transform [22, 23] to enable the maximum data transmission and congestion control and optimal deployment strategies [24, 25] by addressing various deployment techniques such as, fixed, random, grid, hybrid and so on for sensor networks. as for this proposed system, we will focus on measurement of parameters, such as temperature, conductivity, turbidity, salinity, ph, dissolved oxygen and total dissolved solids of water. for this, fsns are excellent choice for monitoring different parameters and properties of water. the nodes will be equipped with these sensors and deployed into water bodies. these nodes will communicate via a wireless medium with sink node available at base station. for this task, various floating sensor nodes will be deployed fixed and randomly into water reservoirs. the nodes will be distributed for collecting the data and then transmit it via a prescribed wireless channel to base station and remote station for end user analysis. for continuous monitoring, energy harvesting mechanism will be provided. solar and wind energy sources are incorporated to handle the power requirements. the harvested energy is stored in super capacitors and secondary batteries accordingly. to maintain the energy flow and ratings, an energy aware mechanism will be accorded. we also turn our focus on data transform by touching reliable data transfer and congestion control mechanisms and algorithms. a gui tool will be designed for analyzing the results and statistics of water quality. there are two types of users for the analysis of water quality results, which are technical (experts and researcher) and nontechnical people. for non-technical user, we will design a simple gui tool for displaying the data. 1.1. motivation as pakistan is populous country and it is facing huge water crises. so far, to overcome this issue we must take initially necessary steps for making water pure, for this; first the properties of water must be calculated to purify or improve its qualities. the water quality is an essential ingredient that plays a pivotal role for living organisms, their basic sarang karim (et al.), energy harvesting for water quality monitoring using floating sensor networks: a generic framework (pp. 1932) sukkur iba journal of emerging technologies sjet | volume 1 no. 2 july – december 2018 © sukkur iba university 21 needs and routine jobs, such as drinking, cooking, farming, etc. so far, this proposed system will be supportive to measure key parameters of water, which are necessary for the treatment of saline and soiled water. by measuring the key parameters, it will easily be arbitrated that whether this water is useful for drinking and irrigation or it would be treated. hence, this proposed system will fulfil all these aspects and will be suitable to achieve this task. 1.2. research challenges these research challenges will be faced during designing water quality monitoring system.  fsns are not suitable for continuous monitoring of water bodies/reservoirs, because they have limited life to measure the water parameters.  the most significant challenge in the framework is interdependencies between the simulated scenarios and physical components of the system.  there is no any sustainable energy mechanism for fsns to collect continuous data.  energy harvesting subsystems are not easy to model in existing wsn simulators.  some realistic properties of the energy harvester are very challenging to implement in a simulator using a highlevel programming.  design of complex algorithms for scheduling the different modes of the nodes like idle, sleep, sense, transmit, etc. to maximize the network lifetime and conserve more energy.  reliable data transfer in sensor network is a standout amongst the most essential issues.  significant resources are wasted when water quality data is missing, or instruments are not properly configured. 1.3. contribution our contribution in this paper includes: 1) we have proposed a novel framework based on fsn for monitoring the water quality data. 2) in addition, we integrate energy harvesters into our framework for providing the continuous power supply. we also add super capacitors and batteries for storing the extra harvested energy. that can be used as a standby to cope the energy failure. 3) next, we include a block for the reliable data transformation. this helps to maximize the data delivery ratio and curtails the packet loss ratio. 4) in last, an application is also suggested to get water quality data at remote or end users in terms of graphs and statistics. in this study, paper organization is described as: section ii covers the state-of-theart. problem statement is described in section iii. in section iv, the research questions are addressed and the proposed generic framework for the system is described in section v. section vi is all about the architecture of system and in addition, a novel architecture of fsn node to monitor the water quality data is also given. in section vii, the proposed methodology is illustrated. expected outcomes in section viii, conclusion is given in section ix. 2. state of the art here we discuss some existing work of different domain of research areas. in last, a comparative analysis is also given in table i. 2.1. floating sensor networks a. tinka, et al. (2013) [5] have presented a complete drifter system and acknowledged a pilot experiment in a controlled channel. the utility of the system for making sarang karim (et al.), energy harvesting for water quality monitoring using floating sensor networks: a generic framework (pp. 1932) sukkur iba journal of emerging technologies sjet | volume 1 no. 2 july – december 2018 © sukkur iba university 22 measurements in unknown environments is highlighted by a combined parameter estimation and data assimilation algorithm using an extended kalman filter. these drifters were utilized to measure water quality data; do, temperature/conductivity and ph. d. boydstun, et al. (2015) [7] have given the design, development and deployment of sensor network of drifter nodes. the target domain is coastal water monitoring and study of lagrangian water dynamics. the nodes were equipped with a camera, inertial measurement unit (imu), gps, wi-fi and a computing unit. each unit is water resistant with buoyancy characteristics that enable it to float in a vertical position. 2.2. water quality monitoring yue and t. ying, (2011) [8] have designed a wsn based system for water monitoring system and focused on measuring the oxygen content, turbidity and ph value of water. the system is powered via a solar cell. wsn nodes distrusted randomly and a sink node at base station for collecting the water quality data. the main advantage of this system is low power consumption and flexibility in deployment. w. y. chung, and j. h. yoo (2015) [9] have designed wsn based field servers to sense the information about water quality parameters from wide areas such as; coastal areas, rivers and streams. they have used solar energy harvester to energize the field servers. for the reduction of communication traffic and adequate data transmission in the middle of base station and field servers, they have designed a data averaging practice. b. o’flynn, et al. (2007) [11] have worked on measuring water quality parameters and wsn based multi sensor system design and titled as smart coast; a new platform has been designed and implemented for the investigation of water parameters for water quality management and measurement. sensing devices of smart coast system were temperature, ph, oxygen content, conductivity, turbidity, and water level of water bodies. d. s. simbeye and s. f. yang, (2014) [12] have designed real time wireless system for monitoring as well as controlling the various parameters of water. the parameters under monitoring and controlling were ph value, temperature, oxygen content, and water level. the sensed data transmitted via zigbee transmitter to the base station. the lab view platform has been used for the analysis of outcomes. 2.3. energy harvesting f. k. shaikh, and s. zeadally (2016) [15] have presented a comprehensive review on the taxonomy of renewable energy sources towards wireless sensor networks and focused two classes of energy harvesting sources i.e., ambient sources and external sources. rf, solar, thermal and flow (wind and hydro) are lies under the category of ambient sources and mechanical (vibration, pressure and strainstress) and humanoid (bodily, physical and activity) falls under the external energy harvesting sources. a. dewan, et al. (2014) [16] have reviewed about the renewable energy sources for powering the environmental monitoring systems located at remote areas. their proposed system is a best alternative to the traditional batteries. researchers initially discussed about remote sensors and then the power requirements and working principle of renewable sources for remote sensors, renewable energy sources challenges and finally, the power management. 2.3. harvesting techniques j. j. e. lopez, et al. (2018) [31] suggested that presently, batteries are generally used to power-up internet-of-things (iot) devices. though, use of batteries enforces significant restrictions to operation of system, because they require be recharging or interchanging after certain period of time. depending on proposed application, this can be a very sarang karim (et al.), energy harvesting for water quality monitoring using floating sensor networks: a generic framework (pp. 1932) sukkur iba journal of emerging technologies sjet | volume 1 no. 2 july – december 2018 © sukkur iba university 23 challenging process or even not possible choice. to overcome these restrictions, designers are recurring to energy harvesting (eh) systems to extend battery life and allow independent operation of iot end-nodes. in current years, several power management units (pmus) that harvest energy from single transducers have been introduced. the most common selected sources of energy are light, thermal gradients, mechanical vibrations and radio frequency (rf) signals. though, it has been observed that due to ambient variations, single harvesting sources can exhibit long periods of energy shortage, which reduces their overall dependability. as main goal of a pmu is to provide a constant supply to its load, even when operating from irregular energy sources; design of an autonomous system that relies on single harvesting source can be quite challenging. collecting energy from several sources turns to be more reliable method for powering iot end-nodes. this is especially case if complementary / heterogeneous transducers are considered as harvesting devices. 2.4. data transformation s. o. olatinwo, and t. h. joubert, (2018) [28] suggested that wireless sensor network (wsn) technology is promising inexpensive method which involves deployment of different sensor nodes measuring water quality at a desired water-processing station. monitoring parameters might normally include inorganic and organic contaminants such as ph detection, dissolved metal ion detection, and bacterial load detection. the data collected by waterquality sensor nodes concerning quality of water at water processing station is transmitted to different data centers. the data centers investigate water quality data, based on analysis and essential conclusions are made. wsn is not only valuable tool employed in water quality monitoring but also for water leakage monitoring, traffic monitoring, to collect, process, and distribute environmental data to several centers. b. ali, et al. (2018) [30] have proposed a reliable and energy-efficient routing (rerp2r) protocol for uwsns water quality monitoring. this protocol balances energy consumption and decreases delay by utilizing physical distance at time of data packet transmission. every sensor node calculates estimated transmission count for each of its neighbor to find link quality for reliable transmission of data packets. a lowest depth neighbor in range with high residual energy and good link quality is selected as forwarder. r-erp2r forwards only one copy of a data packet to increase network lifetime. however, if a data packet reaches void region, sensor node drops it which results in retransmissions. 2.5. wsn deployment for water quality monitoring a. goswami, and m. kumar. (2017) [26] has presented concise review of protocols in wsn for energy harvesting. in water quality monitoring: wsns can be deployed under water or at surface to detect quality of water and create a more perfect map of water status from all of above-mentioned sources. wsn reduces manual retrieval of data and inspires his team to help detecting places which are facing difficulties to access right quality of water. m. pule, et al. (2017) [27] viewed that water quality monitoring has thus become important to supply of clean and safe water. wireless sensor networks (wsn) have since been considered a promising alternate to complement conventional monitoring processes. these networks are relatively cheap and permit measurements to be taken remotely, in real-time and with negligible human interference. . sarang karim (et al.), energy harvesting for water quality monitoring using floating sensor networks: a generic framework (pp. 1932) sukkur iba journal of emerging technologies sjet | volume 1 no. 2 july – december 2018 © sukkur iba university 24 table i. comparative anlysis between proposed framework and existing frameowrks. sr. # compared parameters existing frameworks [8] [9] [10] [11] [12] [29] [31] this work 1. water quality sensors         2. energy harvesting techniques         3. energy management         4. enrergy storage         5. iot features         6. gps module         7. gui tool         8. database / memory         9. end user application         3. problem statement after the illustration of extensive literature review, it is concluded that the designed platforms and systems have not capability of continuous monitoring. besides this, there is no any sustainable energy mechanism for fsns to monitor the water quality data. fsns are not suitable for continuous monitoring of water reservoirs. they have limited life to measure the water parameters. to overcome these issues, we have proposed to design a novel system in which there is no issue regarding power for operating the fsns everlasting. the nodes should have capability of continuous monitoring of water bodies. nodes should fetch the data autonomously. the considerable problems of fsns are energy management, reliable data dissemination, congestion detection, deployment strategy, security and management of a sensor network itself. the main problem is to simulate the network protocols in parallel with the environmental parameters, energy harvester, circuits and storage blocks. also, it is an utmost issue for a node deployment strategy to meet the design objectives. generally, the deployment of sensor nodes produces congestion in sensor networks. lifetime evaluation of sensor networks is a challenging task, for which, these parameters require much consideration for the robustness:  energy harvesting and storage block  node scheduling  reliability and congestion control in the network  optimal node deployment  ad-hoc nature 4. research questions following are research questions of proposed work. 1) is this course is limited to certain domain of water quality monitoring i.e. ocean, sea, streams, lakes, irrigation, drinking water, etc.? 2) are we familiar about the parameters either natural/manmade that will affect the values of our concerned measuring parameters for water quality data? sarang karim (et al.), energy harvesting for water quality monitoring using floating sensor networks: a generic framework (pp. 1932) sukkur iba journal of emerging technologies sjet | volume 1 no. 2 july – december 2018 © sukkur iba university 25 3) the proposed system is strictly limited by means of computation, storage and communication. how can we handle and design such low complexity power management solutions for those hardware constraints? 4) does the chosen energy harvesting subsystem model fulfil the needs of network lifetime of sensor node objectives for the desired applicative scenarios? 5) how can we organize duty cycle strategies to control congestion and ensure the reliability of data transmission? 6) what are the key factors that need to be considered for optimal placement of floating nodes at different deployment cases? 5. generic framework the proposed generic framework consists of four different blocks as shown in fig. 1. we must highlight these four blocks. (1) application: fsn based [5-7] continuous monitoring of water parameters [8-14, 29] that will help for improving the water quality, (2) energy harvesting [15-19]: provision of adequate energy for long life monitoring without replacing any battery, (3) data transform [22, 23]: congestion control and reliable data transfer at remote station (4) deployment [24, 25]: random deployment of floating nodes. the purpose of each block of the proposed framework is explained here. 5.1. application as we develop fsn based system for continuous water quality monitoring. once the water quality parameters have been detected, then it becomes easier and simpler to improve its quality by incorporating different chemical procedures. researchers may use this framework according to their desired application scenario like fish farms, habitat monitoring, bridge monitoring etc. 5.2. energy harvesting this block consists of two sub-blocks. first one is energy harvesters such as solar, wind, water flow, etc. for our prosed system, we are supposed to use solar and wind harvester as a renewable energy sources to fulfil the power needs of the proposed system devices like, sensing devices, microcontroller, communication devices, and so on. second one is harvesting aware power management. this block is concerned to handle, manage and storage of the harvested energy in super capacitor and secondary batteries and for providing useful energy as per their requirements. 5.3. data transform this block has two types of contributions the reliability module and congestion control. the purpose of reliability module is to transfer data reliably in terms of maximizing the data delivery ratio and minimizing the miss packets ratio. the contribution of congestion control block is to handle the packet transmissions without packet collisions, by incorporating different algorithms to minimize or avoid the number of retransmissions in case of miss or dropped packet scenario. by which, packets collisions are sufficiently reduced. fig. 1. generic framework of proposed system sarang karim (et al.), energy harvesting for water quality monitoring using floating sensor networks: a generic framework (pp. 1932) sukkur iba journal of emerging technologies sjet | volume 1 no. 2 july – december 2018 © sukkur iba university 26 5.4. deployment the deployment of nodes can either be randomly or deterministically. it depends upon the requirement of the network or application designers. well, we use fixed deployment or anchored deployment strategy and random deployment strategy for the proposed system. the pictorial representation of deployment strategies is given in methodology section. the deployment strategies have a significant impact of the network metrics such as network topology, routing protocols, reliable data transfer and so on. so, for improving the network performance, we must adopt a suitable deployment strategy. 6. system architecture fig. 2 depicts the energy process architecture: from harvesting to utilization and partitioned into three main sections as discussed below. 6.1. energy harvesting sources: solar and wind the energy harvesting sources consists of two distinct types of energy harvesters such as, solar and wind to fulfil the energy requirements. for improving the mission-life of fsns, renewable energy sources will be provided accordingly. energy harvester are used to facilitate the proposed system to avoid the abruptness and battery replacement in the measurement of water quality data. the harvested energy obtained from the harvesters is provided to different active electronic devices. 6.2. energy-supply energy sources: super capacitors, batteries, converters and regulators to provide desired voltage ranges as per specifications of devices, this practice is done via power management scheme by incorporating different energy converters and regulators such as mppt. the maximum power point tracking (mppt) [17] provides the maximum output efficiency by maintaining the duty cycles. super capacitors and secondary batteries are here for storing the energy gained from energy harvesters [1719]. 6.3. energy utilizers: processing devices, sensing devices and actives devices this section is comprised of various active devices, which utilizes the energy viz. processing devices, sensing devices and their drive circuitries, communication devices, etc. according to datasheets, every device has different current and voltage ratings. so, for the provision of adequate energy as per device requirement is accomplished by energy converters and regulators as discussed as earlier. fi g. 2 . energy process architecture: fro m har vesting to utilization fig. 3 describes the black box general architecture of a novel fsn node for the proposed system, where different modules of the node are mentioned. the proposed energy harvesting sources solar wind multi-supply energy sources supercapacitors batteries converters and regulators energy utilizers processing devices sensing devices other actives devices sarang karim (et al.), energy harvesting for water quality monitoring using floating sensor networks: a generic framework (pp. 1932) sukkur iba journal of emerging technologies sjet | volume 1 no. 2 july – december 2018 © sukkur iba university 27 architecture of fsn node consists of sensing devices, microcontroller unit, zigbee transceiver, gps module and power management blocks (power source and energy buffers). sensor node is composed of sensing devices along with drive circuitry and converts to enable the sensors for the communication with microcontroller unit. the fetched data is transmitted by zigbee transceiver at the base station. gps is used to track the position and location status of the nodes. to provide desired voltage ranges according to the specifications of devices; this practice is done via converters, mppt controller and power management scheme. fi g. 3 . fsn node general architecture this fsn node has three different challenges, which are: shaping a new platform for real time monitoring efficiently, development of software algorithms to incorporate hardware for autonomous monitoring and data transferring, incorporation of various modules of the node with the microcontroller unit to achieve desire objectives by making it fully quantifiable. 7. reseach methodology the deployment scenario of floating nodes is depicted in fig. 4, in which fixed or anchored deployment is depicted in fig. 4a and random deployment is depicted in fig.. 4b for designing any novel platform for performing some dedicated tasks. the datasheet for each part of the system must be observed before selecting for proposed system. we are aimed to design a novel hardware platform for real time continuous monitoring of water quality parameters. there are various software platforms for the programing of the nodes. for the visualization of measured data, a gui tool will be designed and database for record keeping. the proposed system is comprised of a sink node at base station and various number of sensor nodes deployed in water bodies. zigbee transceiver is responsible for transferring the data to base station. the gps module will be equipped with sensor nodes for tracking the position and location status. the nodes will be deployed randomly into water reservoirs for real time monitoring and continuously. our proposed methodology is based on following five steps: 7.1. data collection in the first step of proposed system of the network various floating nodes will be deployed in the water (lake or river). each node will be equipped with different sensors which are temperature, conductivity, turbidity, salinity, ph, dissolved oxygen and total dissolved solids. these nodes will be designed and programmed to collect water parameters individually and that sensed data after collection is stored in the microcontroller accordingly. 7.2. data transmission in the second step, the data will be transmitted wireless, and zigbee transceiver module will be used at transmission and reception sides. all nodes will send the collected data to central monitoring center or base station using direct topology. the position of each node is also accorded at base station via gps module for updating the status of locations. 7.3. base station in the third step, base station will collect the data from all floating nodes using zigbee transceiver, where visualization of data via gui tool will be carried out. after receiving data from each node, the data is sent to the ethernet shield which is used as a gateway to transfer the data over web for end user. energy harvesters: solar wind sensing devices: (water quality sensors) energy storage: supercapacitors batteries converters: adc/dac regulators (constant power supply) transceiver gps module sarang karim (et al.), energy harvesting for water quality monitoring using floating sensor networks: a generic framework (pp. 1932) sukkur iba journal of emerging technologies sjet | volume 1 no. 2 july – december 2018 © sukkur iba university 28 (a) anchored/fixed deployment (b) rando m deploy ment fi g. 4 . proposed research methodology 7.4. www in the fourth step the data will be sent over the web, by which the data is accessed by the server for further processing. also, end user can access the data via internet sources. 7.5. server in the last step the data will be received at server via internet and stored in the database for further processing, initially the data will be differentiated using the node ids to process the data of each node separately, after sarang karim (et al.), energy harvesting for water quality monitoring using floating sensor networks: a generic framework (pp. 1932) sukkur iba journal of emerging technologies sjet | volume 1 no. 2 july – december 2018 © sukkur iba university 29 identification the data is collected by web for final step, over here three tasks will be executed which are given below.  status check: this is used to check the status of each node whether it is up or down, sometimes the transmission is interrupted because of higher attenuation causing object in between or temporary failure of link etc.  graphs generation: here, the data of each sensor is used to generate a continuous line graphs to show the instantaneous values and status of the water relating to the sensor. notifications/alerts: notifications and alerts will be used to indicate if any of the water parameter is not in the desired state and has crossed threshold, it will be notified by triggering warning to use precautions to make the parameters back to normal 8. expected outcomes the proposed energy harvesting based fsn system is beneficial for both public and private sectors. the proposed novel system tackles two most key issues; energy and water that are being faced in our country pakistan very dramatically. furthermore, we have evaporated some other pivotal role of our system under following sections. 8.1. industry there are various water-purifiers, food factories, raw material (cement, etc.) factories and industries are available around the world, for these procedures, safe water is an important ingredient. for the provision of safe and hygienic water, water quality monitoring system will play pivotal role for the treatment of water. this proposed system is fit for this requirement. 8.2. academia academia is the main part of research in this world and day by day it is promoted exhaustively by fetching and executing the ideas that are developed by the researchers. by working on this project, we can develop the linkages of useful research among the researchers and can produce different creative domains of research for further enhancement and improvement in the water quality monitoring domain. 8.3. community as water is the fundamental need of human beings and other living organisms. according to medical research, a common human being is using average of 10 liters of water every day for their survival on this earth and obviously being a sensible human, we cannot tolerate the quality factor of this basic need. hence, by monitoring the parameters of water we can improve the quality of water at its best, so that, every living organism can access or avail good quality water. 8.4. government after successful compilation of the statistics of water quality data, government can invest to develop some water purification plants to provide the best quality water to industries, communities, and other sectors of environment around us. 9. conclusion the proposed work has provided the details regarding the experience picked up in the context of development of a system of floating sensor network for collecting water quality data by introducing a novel framework. the proposed framework comprised of four domains; 1) application (e.g., water quality monitoring system), 2) energy harvesting, 3) data transform and 4) deployment. meanwhile, each block also classified into sub-classes. we have addressed to propose a system based on fsn to monitor the water quality data continuously. for which we have introduced a novel architecture for fsn node platform. the fsn node is equipped with in-situ sensors; the fsn collect the data and transmit it at the base station via zigbee transceiver module. where measured data is displayed on sarang karim (et al.), energy harvesting for water quality monitoring using floating sensor networks: a generic framework (pp. 1932) sukkur iba journal of emerging technologies sjet | volume 1 no. 2 july – december 2018 © sukkur iba university 30 a display tool for users and a database for record keeping. as well as, this data is transmitted at remote station for end users via internet. for the accomplishment of continuing monitoring, the alternating energy sources such as solar wind is provided to fsns. the data transform module is addressed for the improvement of data reliability of the proposed system and avoid the congestion created during the data transmission. the proposed methodology of fsns node deployment are addressed to be fixed deployment and random deployment at different outdoor sites for continuous monitoring. finally, we have highlighted the end users and beneficiaries for which this proposed system is useful for the water treatment procedures. acknowledgment the authors are thankful to iict, mehran university of engineering and technology, jamshoro, pakistan and electronics engineering department, quaid-e-awan university of engineering, science and technology, nawabshah, pakistan for providing the necessary support. references [1] r. m. white, “a sensor classification scheme”, ieee transactions on ultrasonics, ferroelectrics and frequency control, vol. 34, no. 2, pp. 124–126, 1987. [2] i. f. akyildiz, w. su, y. sankarasubramanian, and e. cayirci, “a survey on sensor networks,” ieee communication magazine, vol. 42, no. 5, pp. 102–114, 2002. [3] i. f. akyildiz, w. su, y. sankarasubramaniam, and e. cayirci, “wireless sensor networks: a survey”, computer networks, vol. 38, no. 4, pp. 393– 422, 2002. [4] m. f. othman and k. shazali, “wireless sensor network applications: a study in environment monitoring system”, international symposium on robotics and intelligent sensors, vol. 41, pp. 1204 – 1210, 2012. [5] a. tinka, m. rafiee, and a. m. bayen, “floating sensor networks for river studies”. ieee systems journal, vol. 7, no. 1, pp. 36– 49, 2013. [6] j. beard, k. weekly, c. oroza, a. tinka and a. m. bayen, "mobile phone based drifting lagrangian flow sensors," ieee 3rd international conference on networked embedded systems for every application (nesea), pp. 1-7, 2012. [7] d. boydstun, m. farich, j. mccarthy, s. rubinson, z. smith and i. rekleitis, “drifter sensor network for environmental monitoring”, computer and robot vision (crv), 12th conference on, halifax, ns, pp. 16-22, 2015. [8] r. yue and t. ying, “a novel water quality monitoring system based on solar power supply & amp; wireless sensor network”, international conference of environmental science and engineering, vol. 12, part a, pp. 265 – 272, 2012. [9] w.y. chung, and j.h. yoo, “remote water quality monitoring in wide area”, sensors and actuators b: chemical, vol 217, pp:5157. 2015. [10] a. faustine, a. mvuma, h. mongi, m. gabriel, a. tenge, and s. kucel, “wireless sensor networks for water quality monitoring and control within lake victoria basin: prototype development”. wireless sensor network, vol 6, pp: 281-290, 2014. [11] b. o'flyrm, r. martinez, john cleary, c. slater, f. regan, d. diamond, and heather murphy. "smartcoast: a wireless sensor network for water quality monitoring." in local computer networks, 2007. lcn 2007. 32nd ieee conference on, pp. 815-816. ieee, 2007. [12] d. s. simbeye and s. f. yang, “water quality monitoring and control for aquaculture based on wireless sensor networks”, journal of networks, vol. 9, no. 4, 2014. [13] j. wang, x. ren, y. shen, and s.y. liu, “a remote wireless sensor networks for water quality monitoring”, innovative computing communication, international conference on and information technology ocean engineering, pp. 7–12, 2010. [14] p. jiang, h. xia, z. he, and z. wang, “design of a water environment monitoring system based on wireless sensor networks”, vol. 9, no. 8, p. 6411, 2009. sarang karim (et al.), energy harvesting for water quality monitoring using floating sensor networks: a generic framework (pp. 1932) sukkur iba journal of emerging technologies sjet | volume 1 no. 2 july – december 2018 © sukkur iba university 31 [15] f.k. shaikh, and s. zeadally, “energy harvesting in wireless sensor networks: a comprehensive review”. renewable and sustainable energy reviews, vol 55, pp: 10411054, 2016. [16] a. dewan, s. u. ay, m. n. karim, h. beyenal, “alternative power sources for remote sensors: a review”, journal of power sources, volume 245, pages 129-143, issn 0378-7753, 2014. [17] f. akhtar and m. h. rehmani, “energy replenishment using renewable and traditional energy resources for sustainable wireless sensor networks: a review”, renewable and sustainable energy reviews, vol. 45, pp. 769 – 784, 2015. [18] p. d. lund, j. lindgren, j. mikkola, and j. salpakari, “review of energy system flexibility measures to enable high levels of variable renewable electricity”, renewable and sustainable energy reviews, vol. 45, pp. 785 – 807, 2015. [19] b. s. srujana, neha, p. mathews, and v. harigovindan, “multi-source energy harvesting system for underwater wireless sensor networks”, international conference on information and communication technologies, icict, vol. 46, pp. 1041–1048, 2015. [20] p. nintanavongsa, “a survey on rf energy harvesting: circuits and protocols”, energy procedia, volume 56, pages 414-422, 2014. [21] s. peng, t. wang, and c. low, “energy neutral clustering for energy harvesting wireless sensors networks”, ad hoc networks, vol. 28, pp. 1 – 16, 2015. [22] p. yadav, and u.k. verma, “wireless sensor network (wsn): a reliable data transfer using spaced hop by hop transport”, international journal of engineering science invention, volume 2 issue 5, pp.26-30, 2013. [23] f. yunus, n. s. n. ismail, s. h. s. ariffin, a. a. shahidan, n. fisal and s. k. syed-yusof, “proposed transport protocol for reliable data transfer in wireless sensor network (wsn)”, 4th international conference on modeling, simulation and applied optimization (icmsao), kuala lumpur, pp. 1-7, 2011. [24] a. rahman, a.r. alharby, h. hasbullah, and k. almuzaini, “corona based deployment strategies in wireless sensor network: a survey”, journal of network and computer applications, volume 64, pp: 176-193, 2016. [25] g.s. rao and v. vallikumari, “a beneficial analysis of node deployment schemes for wireless sensor networks”, international journal of advanced smart sensor network systems (ijassn), vol 2, no.2, 2012. [26] a., goswami, m., kumar, ”a review on energy harvesting in wireless sensor networks” international journal of innovative research in science, engineering and technology, issn(online) : 2319-8753 issn (print) : 2347-6710, vol. 6, issue 4, 2017. [27] m. pule, a., yahya and j. chuma, “wireless sensor networks: a survey on monitoring water quality”, journal of applied research and technology 15 pp: 562–570 2017. [28] s. o. olatinwo and t. h. joubert, “optimizing the energy and throughput of a waterquality monitoring system” sensors 18, 1198, 2018. [29] l. parra, s. sendra, l. garcia, and j. lloret, “design and deployment of low-cost sensors for monitoring the water quality and fish behavior in aquaculture tanks during the feeding process”, sensors 18, 750, 2018. [30] b. ali, a. sher, n. javed, k. aurangzeb, and s.i. haider, “retransmission avoidance for reliable data delivery in underwater wsns”, sensors, 18(1), p.149, 2018. [31] j. j. e. lopez, a. abuellil, z. zeng, and s. e. sánchez, “multiple input energy harvesting systems for autonomous iot end-nodes” journal of low power electronics and applications, 8(1), 6., 2018.