Acta Polytechnica Vol. 43 No. 412003 On Planning and Managing the Presenration of Historical Buildings i. Jarsky The process of preseruing and, reconstructing historical build)ngs poses seaeral specif.c questions and, raises problems uhich n'ust be solaed in the planning and mnnagernent stage of the building process - frorn questions of architectural and art-histori.cal signift cance , ai.a the future purpose of use of the builting, links to the surrouniling buiWings, enuironmental quest'ions, questions of cost, time ana$sis, and quality assurance problems. Mony of thew problems can be solued with the help of a computer nod.el of the course of the rehabilitation and reconstruction of the building created by a construction technologl networh diagram. The CONTEC integrated project planning, mnnagernent and qu,ality control systern based on these diagrams has been used for bi.dd.ing, planning and managing the reconshuction process ofseueral signifcant historical buildings'in Prague and other cities. Keyaords: reconstruction, historical buildings, project management, planning, quality assurance, construclion technology network diagrarn. I Introduction Many historical buildings have been reconsrrucred in rhe Czech Republic in recent years, especially in Prague. In the planning and design stage ofthe reconstruction several spe- cific problems have to be solved, and many considerations have to be taken into account in this decision process. The main questions are raised in the fields of architectural and art-historical significance, links to the sumounding buildings, environmental questions, questions of the future purpose of use of the building, technical problems of optimum choice of different constructions, cost and time analysis and problems of quality assurance and control. Some of these problems can be solved effrciently by creating a computer model of rhe flow of the building process of the reconstruction. The model must be based on an analysis of the construction technol- ogy of the reconstruction process, and must reflect all the main considerations and architectural, technical, technologi- cal and financial aspects of the building process. The user must be able to create and update the model very quickly, because especially when reconstructing historical buildings the conditions for the flow of the reconstmction process can often be changed, e. g., by the actual stare ofrhe load-bearing structure, discoveries of historical paintings, fiescoes or ar- chaeological remains, etc. Such discoveries have a significant influence on the continuation ofthe reconstruction process, especially from the point of view of the deadline. Therefore the CONTEC computer-based integrated project planning, management and quality control system, based on the con- struction technology network, has been used in recent years for planning and managing the reconstruction process of sev- eral significant historical buildings in Pragr.re and in other cities. The linkage to the quality assurance system appears right from the first stage of planning of the project [l]. It is desirable to be able to make furtheruse of the documents sub- mitted during the bidding process for actual managemenr of the construction processes on site and for quality assurance of the whole project after a contractor has been selected. In or- der to make such evaluations as precise and quick as possible, an expert computer-based project planning and manage- ment system, named CONTEC, has been developed. CON- 36 TEC is capable of modelling very quickly not only the build- ing process of the project itself, including an analysis of cosrs and other resources, but simuhaneously the process of main- tenance [2] and reconstruction needed in years to come, and even the process of demolition, if need be. The main aspecrs of the erection and maintenance process that need to be evaluated are the minimum costs during the lifetime of a building [3]. 2 What the model of the building process is required to proYide The investor's feasibility study must answer some key questions, e.g., what the price of the project will be, what rhe time schedule and the course of the building process will be, and whether it is possible to keep to the required project deadline from the technological point of view. The total de- sired time of service and the quality level also have to be stated. It is desirable for the investor to be able to model some of the contractor's data about the building process of the pro- ject, especially what the actual costs of the project will be and therefore the resulting profit, how many specialist craftsmen will be needed, what sorts of machinery will be needed on site, and when, how the cash flow and finances will be managed, and how the quality of the project and its parts will be assured and controlled. Wth the help of the CONTEC system, the invesror and the contractor can simulate the proposed time and resource flow of the building process of the project on a microcom- putef even ifthe relevant topical data about the project in the planning stage is very poor. The more precisely the task is de- termined, the better the results that can be obtained from the model. On the basis of typical network diagrams and a database of construction processes, a model of the actual erection of a building and a model of its maintenance and re- construction can be automatically created. After completing the model the investor and the contractor can make their decisions about actual resource allocation in time, taking into account the whole time of service (including the influence of inflation), the necessary maintenance and reconstruction cy- cles, and the durability of the structures used in the buildings. The model of the building, maintenance and reconsrruction Acta Polytechnica Vol. 43 No. 412003 process is based on the main docunrents of the constructron technology ctesign [4]. 3 On the methodology and basic documents for construction technology design The methodology for automated creation of the basic doc- uments for the constnrction technology design is described in [5]. The main documents in consrruction technology design include files of technological standards, somerimes referred to as technological analysis sheers or programmes, and net- work diagrams. The close links between these documents used in the CONTEC expert sysrem enable us to elaboiate bar charts, line-of-balance graphs. allocation graphs ofvari- ous technological and economical resources, and quality assurance checklists. In the past, these documents - techno- logical standards (programmes) and network diagrams -were mostly processed subsequently, and separately. Their close relationship with construction technology was often disre- garded, and netrvork diagrams elaborated without consisrent technological analysis contained a number of errors rvhich made them useless for construction project control, leading to loss of money, time and quality. Quality assurance checklists were not usually elaborated at all, or were elaborated by a separate division with no connection to the acrual florv of the building process. The simultaneous elaboration of techno- logical standards, network diagrams, cost analysis and qualit,v assurance checklists used in the CONTEC expert sysrem eliminates the processing of network diagrams without a technological analysis, and enables use to be made of the close link between technological standards and documents for quality management in the project. The technological standard (technological analysis sheet or programme) determines the technological structure of the production process (the sequence of construction processes, volume of production, labour and cost consumption, number and type ofworkers or machines, etc.). According to rhe calcu- lated network diagram the technological standard includes a bar chart, which indicates the time structure of the production process. A technological scheme showing the spatial srrucrure of the process is usually added. The connection between the time stnrcture and the spatial structure of the building process is shown in the line-of-balance graph. The quality assurance checklist, which is automatically created according to the technological standard, consists of instructions for per- forming the quality checks of the resulting product ar each stage in the construction process. The values for the duration of the processes and the mini- mum working space necessary can be used ro make (with regard to the direction ofthe course ofthe processes) a critical approximation of the construction processes. These processes can then be immediately linked optimally in the construction technology network diagram method, taking into account the quality of the resulting products of the construction pro- cesses. 'lhus all the documents mentioned above after the network diagram calculation depict floats in the construction processes. The floats are subsequently used to optimise the building process, taking into account the limited resources in different time periods. 4 Basic facts on links in'the construction technology network analysis method The constr-uction technolo6T nerwork analysis method used by the expert system lvas designed for simultaneous evaluation of technological standards and network diagrams, and for optimal linking of the construction processes (most elficient use of working space on site for eflicient economical and safe performance of construction processes, including technological pauses [5]). The neftvork analysis method uses the activity-on-node netrvork diagram. AIi four types of links of activities introduced in the precedence graph method (finish - start, start-- srarr, critical approach and finish - fin- ish), [6, 7], are also included in the consrruction technology network analysis method. The main disadvantage of the precedence graph method is the need to know the actual val- ues of the lag times between each two activities that are linked together, and their duration, while creating rhe net- work diagram. This rvould make concurrent evaluation of the technological standard and of the netlvork impossible. Therefore the construction technology network analysis method introduces the 5th type of link, the construction tech- nologr link. This results from the condition of release of the minimum rvorking space on a structure by the previous lvork gang, so that the follorving work garrg can start as soon as pos- sible. The lag time is not given by a certain time value but it is calculated by the computer according to rhe duration of iinked activities and accor-ding to the spatial srmcture of the building. This is represented by the rvorking space index f. This index is determined by the ratio of rhe minimum work- ing space needed for the gang divided by the total rvorking space in the building. For example, in an 8-srorey administra- tive building the usual minimum working space is 2 floors, so the rvorking space index f is 2/8, i.e., 25 7o, see Frg. l. Intro- ducing this link in the CONTEC method not only simplifies the input of the data of the nenvork diagram but also permits extensive formation and utilisation of tvpical network dia- M M - minimum working space T - total working space available T f- working space index Fig. 1: Workinl ,pu.. i.ra.* grams as computer files for the erection, maintenance and re- construction ofvarious sorts of buildings. These can be modi- fied according to the spatial stmcture of the actual building. There are usually only three main types of working space for diflerent activities on site (t for underground structures or works on the roof, f, for erection and plumbing, t for finish- ing works). Thus only three values of the main working space indices are sufficient to evaluate practically all technologi- 1= Y .loo t%l T ct Acta Polytechnica Vol. 43 No. 412003 cal constraints in the building prpcess. In a typical network diagram the values of the working space indices are given parametrically, While stating data about the actual building, a typical network diagram can be modified stating only the three main working space indices. al (t;T')<(t,-Ti) b) (4-T')>$-ri) tr,,) 1"tr Fig. 2: Principle of the construction technology link The situation where two processes of technological stage i andj are linked is illustrated in the line-of-production graph on Fig. 2 a, b. Each process of a technological stage (e.g., foundation, superstmcture, etc.) consists of several construc- tion processes (work gangs, e.g,, formwork, reinforcement, concrete laying, etc.). Values t,andt, represent the duration of processes of technological stage,' T, and T, their time of launching, ry the technological pause after iompleting ac- tivity i,fris the working space index. In the first case (Fig. 2 a), if the last construction process in the preceding process of technological stage i is shorter than the first construction process in the following process of technological stage j, the lag time e can be automatically calculated according to for- mula (l) 6=(t; -'r).f;1 +T;+TP;+ 6 (l) Value 6 rounds the lag time to whole time units, so that the relevantwork gangwill start its work at a certain time unit in the morning. If the first construction process in the follow- ing process of technological stageT is shorter than the last construction process in the preceding process of technologi- cal stage i, (Fig. 2 b), then the lag time e is calculated accord- ing to formula (2) ,=(t, -r;).f4 +r1+r{ + 6. (2) In the time analysis of the nenvork diagram using the con- struction technology link, the start of the following activity j, denoted Sr, can be calculated during the forward calculation 38 r-!--1 according to formula (3), and the completion of the preced- ing activity l', denoted 4, can be calculated during the back- ward calculation of the network diagram according to for- mula (4). sj = *u*{[s;+(t;-r)'fq1+'ri+rfl'+ 6]; (3) [s; + q - t1 +(t1 -rj) fr+ t + rP; + s]] 4 = min{[f -, -rPi*(r- f).(r; -l)-o]; (4) foi *ri -rP; - ft (,; -ry) - u]) The construction technology network analysis method goes on to introduce the 6th type of link, the florv link, which results from the condition of the continuous course of a constnrction process on different products, e. g., sections, buildings, etc. The 7th and 8th types of link, partial links, describe the condition that a following activity may srarr (or must tinish) after the completion of a cerrain part of the previous activity, or vice versa. These links are determined by partial link indices that represent the ratio of the duration of the finished part of the previous activity divided by the total duration of the previous activity (type 7), or the ratio of the duration of the unfinished part of the following process divided by the total duration of the follorving process (type 8). If this index is negative it represents the same ratio but for the following (type 7) or preceding (type 8) activity. With the use of the flow link, modified typical network diagrams or evalu- ated network diagrams of buildings can be automatically linked into a larger network that may represent the building process of the whole project, consisting of many buildings, e.g., a housing estate, an industrial plant, or its maintenance or reconstruction. In this case the flow lins are generated by the system in the activities performed by specialised work gangs that proceed continuously from one building to another. The nenvork diagram can be calculated on a deter- ministic or stochastic basis, [5]. 5 Modeling the erection, maintenance and reconstruction of buildings The main condition for modelling the erection, mainte- nance and reconstruction process is a statement of the task and the intentions of the investor and architect and the links to the external environment. In the very first stage we usually know, e.9., that there is an intention to reconstnrct certain buildings with a certain built-up area. There are some propo- sitions and drafts about the layout, future purpose of use, level of quality and durability, the structures used, and the dead- line for the building process. fater the investor usually has a certain level of design of the project, including the important bill of quantities. Then, a database for rapid modelling of the building pro- cess is put together. This database consists of the main data about all construction processes affecting the technological stnrcture of the work gangs. This includes the main facts about the deadlines, productivity of labou4 price of the prod- uct, number ofworkers, technological pauses and 20 other financial and technological resources (material costs, wages, costs for machinery overheads, average profit, machinery materials, skilled workers, etc.). For automatic modelling of the maintenance and reconstruction data about the average F(J g F(J Acta Polytechnica Vol. 43 No. 412003 durability of rhe marerial, the number of maintenance cycles until reconstruction of the product and marks of the rypical nenuork diagrams for maintenance and for reconstruction are also included. In order to enable quality assurance checklists to-be made quickly, anorher database of checks on the quality of the resulting products (what must be controlled, how, according to which standards, etc.) has been created. The quality check database is linked with the database of consrruc- tion processes [81. A typical network diagram of a reconstruction or mainte- nance process as a computer file contains data about the sequence and linkage of the construction processes. It is preferable to use the construction technology link stated parametrically as much as possible, or other sorts of links with the lag time equal to zero. Under these conditions, typical network diagrams can easily be modified according to the spatial structure of an actual building. The volume of produc- tion and costs and the price of all activities are also included. These are related to an appropriate custom-made unit'of measurement, usually m' of build-in space or m2 of recon- stnrcted area in the case ofa reconstruction. As stated above, the typical constmction rechnology nerwork diagram can be modified according to the spatial srructure of the building process by using the three rnain minirnum working space indices. When the user simulates the building or reconsruc- tion process, the first stage is to call up the typical network diagram for a certain type of building, rhen ro modify it by stating the actual main working space indices, and the com- puter then generates the first draw model of the erection process, including the time and cosr analysis data, which are transferred from the database of construction processes. Thus, the user can get the first model much more quickly than by using classical prgect managemenr systems, which require the network diagram to be creared by adding the relevant activities one after another and stating their dura- tion, resources and links. The created model has to be defined with greater precision, taking account the facts known about the building. It is known that 80 7o of the price and cosrs is influenced byjust 20 7o of activities. The production volumes of these significant processes have to be stated according to the construction design. The production prices, labour con- sumption and required resources are calculated automatically on the basis of the database of activities. If the exact bill of quantities is available, its values can be auromatically trans- ferred into the model. After the calculation of'the nerwork diagram the user receives the earliest and latest dates for starting and completing all activities. By changing the num- ber ofworkers in the gangs or by changing the tension index of time standards the duration of activities and thus rhe whole network diagram can be modified. Activities of all sorts (not only those from the database) can be entered into the net- work. After making these models for all buildings that are included in the project, a network diagram of the whole project can be made by connecting the partial networks and linking them togetherwith flow links in the case of specialised work gangs working continuously in linked buildings creating a building flow. Thus, it is not necessary to create the network diagram individually from the very beginning for each project. The CONTEC system enables a model of the building process of the project to be built up very quickly from prefabricated sec- tions and typical nenvork diagrams ofdifferent buildings, and it can be defined easily and with greater precision according to the facts gained from the invesr.or's data. This can easily be updated if various conditions change. The netrvork can be automatically recalculated with a view to keeping to the dead- line of the project. The system then selects acrivities that have to be shortened, by adding a certain number ofworkers or by increasing the intensity of the work, while keeping ro rhe rech- nological rules, and all links of the nerwork. The sysrem enables the calculated network diagram to be printed in diflerent forms (technological standards, bar charts, line- -of-balance graphs, resource allocation graphs ofprice, costs and cash flow, labour consumption, work force requirements, etc.), in Czech, English, Italian or Russian. Even in the very first stage of the plan the quality assurance checklist can be created by using the database ofquality checks. The particu- lar network diagram can rhen be aggregated into the higher information level of the technological srages, steps ofcomple- tion or into the level of buildings. On the basis of the model of the erecrion of the building, a complete rnodel can be created which includes not oniy rhe erection but also maintenance and reconstruction. Nowadays this can be done interactively on rhe computer with the help of the databases and typical network diagrams as models of maintenance and reconstruction related to corresponding processes, taking into account the durabiliry ofthe products. A computer program has been recently been developed for this purpose, see Fig. 3. The user will have to state the maxi- mum lifetime of the building, indices of inflation and the operating costs for the years to come. Then the computer will be able to choose relevant maintenance rycles Ml - Mx for different construction units and reconstruction models, and rvill sort them in time and automatically connect them into a nefivork diagram. The time periods of individual mainre- nance cycles represented by the arrows in Fig. 3 are read from the database ofconstruction processes, as are the marks ofthe Fig. 3: Scheme for automatic creation of maintenance and reconstruction cycles 39 Acta Polytechnica Vol. 43 No. 4/2003 relevant typical network mainrenance (Ml - Mx) diagrams. After the evaluation of the complete network diagram, the costs and other financial resources for maintenance, recon- struction, operating expenses and costs, for demolition if need be, are recalculated acconding to the inflation rate. The user can make changes in the original erection model, especially in choosing stnrctures with different price and durability, and the computer then generates rhe cor- responding maintenance and reconstruction variant. As a simultaneous time-cost analysis is always done automatically, the user can minimise the total expenses for erecting, operat- ing, maintaining and reconstructing the building at any time. Naturally, all data included in the model can be interacrively edited and recalculated. All documents that are generated on the basis of the con- struction technology network graph can easily be updated according to the actual completion of constnrction processes on site at a certain date. Ifthere is a delay, the system suggests what measures are to be taken in order to keep to the final deadline of the project. At the same time it keeps ro rhe rech- nological rules of the building process. This can be visualised in the comparative bar chart, where the updated version of the building process, drawn in bigger lines, is compared in a single documentwith the planned flow of the process. Critical activities are drawn in red, non-critical activities in green, and delayed activities in blue. On the basis of the recalculated net- work diagram, the line-of-production graph can be automati- cally redrawn on the plotter. The outputs from the system are used for evaluating the operational plans on site and for op- erational registration with the link to the invoicing agenda. The operational registration files from the invoicing sysrem can be used for automatic updating of the network diagram in the CONTEC system and then for recalculating the deadlines for the activities and for the operational plan. A new resource allocation balance results from the updated model of the building process. Quality assurance checklists are updated simultaneously in a similarway, on the basis of qualiry checks. 6 Examples of use on site The main documents related to construction technology and cost analysis created as described above can contain a model of the building process of the project that includes all necessary data for checking and managing the building pro- cess and for balancing the resource allocation. Many cases of reconstruction of historical buildings in the Czech Republic and Slovakia have been prepared and managed in this way. One particularly interesting case controlled by the CONTEC system was the reconstruction of l8 Renaissance houses with Gothic cellars in the Ungelt area in Prague Old Town. The middle of the area is the Tfn Court, which is surrounded by I I houses. The other ? houses are situated nearby. In rhe planning stage a feasibility study was worked out which deter- mined the optimum use of all the space from the architec- tural, historical, technological and financial points ofview. All vaulted ceilings were saved and the wooden ceilings were re- constructed. There are many beautiful architectural details in these buildings (stone portals, staircases, sgraffrto facades, etc.). A part of one of the finished buildings is illustrated in Flg. 4. New built-in units (windows, doors) were produced on the basis of the old photographs and paintings of the area. Project management documents based on the construction technology network analysis were elaborated to visualise the building process divided into construction processes. Another interesting example of the use of the CONTEC system for modelling and cost assessment of a reconstruction process is the Toscano Palace near Prague Castle, see Fig. 5. This Renaissance palace belongs to the Czech Ministry of Foreign AJIairs. The main purpose of the reconstrucrion was to modernise especially the internal equipment of the build- ing while conserving significant architectural and historical details, such as the portals, towers, facade and courtyard. Many old frescoes were discovered in the course of the recon- struction, and these had to be restored. In this case the model of the reconstruction process had to be regularly updated Fig. 4 Part of the reconstructed Tfn Court in Prague 40 Acta Polytechnica Vol. 43 No. 4/2003 Fig. 5: Toscano Palace in Prague - rvestern facade Fig. 6: Promstroibank St Petersburg, Russia - north-wesr facade (approximately once a month). The main significance of the network model lay in its ability to take into account the delays caused by these discoveries and due to other changes, and to calculate the measures to be taken to keep to the final dead- line of the project. Another example of a time and cost analysis performed by the CONTEC system is the reconstruction of the Industrial and Constrrrction Bank building on Nevsky Prospect in St. Petersburg, Russia. This project is planned for completion in summer 2003. The north-west facade of the building is illus- trated in Fig. 6. The building was originally constructed at the end of the 18"'century but completely burned down in 1993. In this case, the beginning ofthe reconstruction was ofcrucial importance. There are very difficult ground conditions on this site, because it lies below the water level of the river Neva. The load-bearing walls have to be underpinned by oblique piles, new diaphragm walls have to be built and many injec- tions, and much ground consolidation have to be performed. The south-east wing of the building will be completely de- molished and then erected in a new form. All ceilings will be - ":),,'..,.t:.-.; -- - ^ demolished and rebuilt. A new glazed steel roof structure will be built, and all necessary technological equipment, includ- ing safes and computer systems for the bank, have to be replaced. In the construction technology and cost analysis the climate and weather conditions have to be taken into account, as they may have a very negative influence on the building process. 7 Conclusions The main construction technology design documents cre- ated with the help of the CONTEC system can form a model of the building process of a project that includes all necessary data for control and management of the building, mainte- nance and reconstruction process. This system enables the creation of a building process model with appropriate cost assessment, and time-cost analysis about 50 times more quick- ly than current project management systems. It can take into account all specific attributes, links and constraints of the reconstruction process for historical buildings. The docu- 41 Acta Polytechnica Vol. 43 No. 412003 ments can thus be used as a part of a feasibility study, bid, con- stnrction technology design and operative plan for project management of the erection or reconstruction process itself. -fhis model can be updated in accordance with the bill of quantities or the cost estimation. Afterwards a quality assur- ance checklist can be automatically created. All documents generated by the system can easily be updated on the basis of actual completion on site at a given date. If there is a delay, the system suggests what measures are to be taken in the future in order to keep to the final deadline of the project. All documents can be automatically translated into Czech, English and Russian. The system can model the costs for the necessary mainte- nance and reconstruction process throughout the lifetime of the building. With the regularly updated databases, the user can model and choose the best construction unit variant according to his goals and requirements, even in the very first stage of planning. The system can be used on IBM PC compatible computers under Windows 9x, ME, NT 2000 or XP operational systems. At present the CONTEC system, linked with various cosr esti- mation systems, is in use in more than 350 investment and contracting firms in the Czech Republic and Slovakia. The experience gained by users is very extensive, and it is used on an ongoing basis for improving and innovating the sysrem, especially in the field of automatic modelling and planning of the regular maintenance of buildings. References tll Ga5parik, l.: Qnliry Management Systern in Constru.ction Firm. Proceedings of International Conference Develop- ments in Building Technology 1996, Faculty of Civil Engineering of the Slovak Technical University Bra- tislava, Slovakia, p. 40-44. t2l Rutter, D. K: Effectiae Maintenance Marnganent from a Rational U ser Perspectiue. International Scientifi c Confer- ence Proceedings STU Bratislava, Slovakia, 1998, p.237-242. Zapletal, l.: Bedeutung dtr lzbmsdauzr uan Bauobjektm beziiglirh dn Gesamtkoslan. Technische Universitiit Mtin- chen, Germany, 1995. Jarsky, e., Kozlovskii, M, Vriina, P; Taorba nabil,ek a sta,uebni technologicfui projektoadni pomoc{ rnikropoiitaie (Bidd,ing and Construdian Technology Design with tlu Help of M'irrocom.puters). Faculty of Civil Engineering, Technical Univelsity, Ko5ice, Slovakia, 1993, p. I92. Jarsky', C.: Automatizoaarui piipraaa a itzeni realizace staaelt (Automated Preparatiun and Marngawnt of Realization of Projects). CONTEC Ikalupy n. Vltavou, Czech Republic, 2004, p.222: Jarsky, (,.: Modclling of the Buitding Process b1 a Computer Expert Systnn. Proceedings of the 8tn International Con- ference on Computing in Civil and Building Engineer- ing 2000, Starrford University, Stanford, California (USA), ASCE Reston VA 2000, p. 566-573. Ahuja, H. N.: Construction Performance Controlbl Netuorks. Wiley, N. Y., USA, 1976. Popenkovd, M: Wia jakosti stalebntho dtla na tuorbu v1- robntho procesu (lnfluence of the Qtality of tlu Building on Creation oJ'the Productinn Process). Proceedings of the lOth International Conference Quality, 2001, Drim rechniky Ostrava (Czech Republic), 2001; p. E40-844. t3l 14l t5l t6l t7) t8l Assoc. Prof. CendkJarsky', DrSc., Ph.D. phone: +420 315 726 910 +420224 353 590 e-mail : jarsky@contec.cz jarsky@fsv.cvut.cz Department of Technology of Structures Faculty of Civil Engineering Czech Technical University in Prague Thdkurova 7 166 29 Prague 6, Czech Republic 42 Scan1 36 Scan1 37 Scan1 38 Scan1 39 Scan1 40 Scan1 41 Scan1 42