Frontiers in Computing and Intelligent Systems ISSN: 2832-6024 | Vol. 3, No. 1, 2023 30 Intelligent Diagnosis of Alzheimer's disease Ruifan Huang1, a, Huifei Xu2, b 1 School of Sun Yat-sen University, Guangzhou 510000, China 2 School of Hangzhou Normal University, Hangzhou 310000, China. a1059577592@qq.com, b1225604713@qq.com Abstract: In this paper, we combine the knowledge of decision tree model and K-means clustering algorithm with knowledge of statistics to solve the problems of Diagnosis of Alzheimer's disease using brain structure. In the step of selecting features, this paper considers both data-based and theoretical perspectives for the analysis of variance in Alzheimer's disease. Based on the data perspective, the value of variance represents the magnitude of data volatility, i.e., data with data volatility has more abilities to cause data changes in feature classification. Therefore, in this paper, a total of 28 indicators of Site-faq were selected as necessary indicators and histograms were made to observe the volatility. After the above data processing, we Use the attached structural brain features and cognitive behavioral features to design an intelligent diagnosis of Alzheimer's disease. For multi- classification models, this paper uses the K-means algorithm to cluster and continue to cluster MCI into SMC, EMCI, LMCI to observe the difference between cluster centers. After clustering 53 indicators, this paper analyzes the three types of cluster centers, mainly to analyze the different points in the number of clusters, and analyzes the difference in the mean value of the characteristics of the cluster centers, and at the same time, this paper observes the differences between the characteristics by visualizing the data. In the end, we analyze them in relation to the time points to uncover patterns in the evolution of different categories of diseases over time. At the same time, due to the large amount of data, this paper only selects a small sample of five features for analysis. Keywords: Decision tree; Random forest; K-means clustering; Pearson coefficient. 1. Introduction 1.1. Problem Backgroud Alzheimer's disease (AD) is a progressive neurodegenerative disease with an insidious onset. It is characterized clinically by a full spectrum of dementia, including memory impairment, aphasia, dysfluency, agnosia, impairment of visuospatial skills, executive dysfunction, and personality and behavioral changes, the cause of which is still unknown. It is characterized by a progressive decline in the ability to perform activities of daily living, with various neuropsychiatric symptoms and behavioral disturbances. The disease is usually progressive in the elderly, with progressive loss of independent living skills and death from complications 10 to 20 years after the onset of the disease. The preclinical stage of Alzheimer's disease, also known as mild cognitive impairment (MCI), is a transitional state between normal and severe. Due to the limited cognition of the disease by patients and their families, 67% of patients were diagnosed as moderate to severe and had missed the best intervention stage. Therefore, early and accurate diagnosis of Alzheimer's disease and mild cognitive impairment is of great significance [1] 1.2. Clarifications and Restatements This paper uses the brain structural characteristics and cognitive behavioral characteristics of the different categories of people provided in the data set to construct an Alzheimer's disease identification model and design an intelligent diagnostic method to accurately diagnose Alzheimer's disease. In this paper, the research is decomposed into four problems shown below. 1). Preprocess the characteristic indicators of the attached data to investigate the correlation between data characteristics and the diagnosis of Alzheimer's disease. 2). Use the attached structural brain features and cognitive behavioral features to design an intelligent diagnosis of Alzheimer's disease. 3). First, cluster CN, MCI and AD into three major classes. Then, for the three subclasses contained in MCI (SMC, EMCI, and LMCI), the clustering was continued to be refined into three subclasses. 4). The same sample in the annex contains features collected at different time points, we will analyze them in relation to the time points to uncover patterns in the evolution of different categories of diseases over time. 2. General Assumptions and Variable Description 2.1. Assumptions 1). Assume that the effect of environmental factors on the composition of ancient glass artifacts will not change the original chemical composition content ratio by 20%. 2). Assume that in the sampling test, there is no human error in the test results, while the error between the test results and the true content should be less than 2%. 3). It is assumed that chemical components not collected in the sampling tests and not studied will not have a significant correlative effect on the content of other chemical components. 4). Assume that there are no interactions between different chemical components or between different representations of the artifacts. 5). For taking into account the impact of ambient temperature and humidity on the test, assuming that the sampling process are in the same environment and the sampling time interval is short. 31 2.2. Variable Description Table 1. Symbol specification table Symbols Description The specific value of the sample of corresponding to the indicator of the parent series Subseries i.e. interpolation rate at the th sample Coefficient of influence of the variable on the classification The variable denotes the probability that the th variable is classified as a barium lead variable Normalized value of a chemical component in the i-th data set Cluster i The sample points in the Sample Means Distance of the point to all other points in the cluster it belongs to The average distance from a point to all points in a cluster that does not contain it Contour coefficient of the point The rank difference, i.e. the position of the number after sorting two sets of data from smallest to largest 3. Problem 1 The process of modeling and solving Problem 1 is shown in Figure 1: Figure 1. Problem 1 solution process 3.1. Task 1: Analysis of relationship 3.1.1. Data pre-processing The flow chart for data pre-processing is as follows: Figure 2. Basic data pre-processing process For the codified data, this paper quantifies them according to the coding serial number, and for the more important codes, i.e., the text coding part, this paper chooses to encode them manually, for example, for the severity of AD, named as follows. Figure 3. Quantitative processing 3.1.2. Model buiding and solving After the selection of indicators, in order to further determine the reasonableness of the selection of indicators. In this paper, ANOVA will be used to determine whether there is a significant difference in the change of each statistic over time. First, ANOVA is introduced in this paper as follows. The statistical inference method used in the one-way ANOVA is to calculate the F statistic and perform the F test. The total sum of squares of variance, denoted as SST, is decomposed into two parts: one part is the variance caused by the control variables, denoted as SSA (sum of squares of variance between groups); the other part is the SSE (sum of squares of variance within groups) caused by the random variables. The relationship between the two variables is shown below [2]. SST = SSA + SS In general, assume that there are k levels and establish the following assumptions. H0: u1 = u2=. . . uk cH1: u1, u2, . . . , uk, not all equal to each other The error within each overall system, mainly the random error caused by random sampling, is called the intra-group error, and the sum of squared intra-group errors is denoted as SSA. SSA = ∑ ni(xi̅ − x̅)2 k i=1 The errors between the totals, mainly random errors and systematic errors caused by random sampling, are called inter-group errors, and the sum of squared inter-group errors is SSE. SSE = ∑ ∑(xij − xi̅) 2 ni k k i=1 The total sum of squared errors of the data is denoted as SST. SST = ∑ ∑(xij − x̅)2 ni k k i=1 Where denotes the jtℎ observation at the itℎ level, denotes the mean value at the jtℎ level, and denotes the mean value of the n observations. SST = ∑ ∑(xij − x̅)2 = SSA + SSE ni k k i=1 The above calculation shows that the total error of the data comes from two main sources: intra-group error on the one hand and inter-group error on the other. It can be shown that when the means of the k overall groups are equal, SSA k − 1⁄ SSE n − k⁄⁄ obeys the F distribution with degrees of freedom k-1 in the numerator and n - k in the denominator. F = SSA (n − 1)⁄ SSE (n − k)⁄ ≤ Fα(k − 1, n − k) 32 Each F value will correspond to a p value, and the larger the F value and the smaller the p value, the less likely it is to accept the original assumption, which is considered to be a large difference in characteristics between groups. Therefore, the smaller the p-value, the more this feature should be preserved. Figure 4. Analysis of variance histogram Pearson correlation analysis is a method used to study the closeness of association between two or more variables. In order to explore which factors are associated with the cause of Alzheimer's disease, so the correlation analysis algorithm is used, and the Pearson correlation value can be a good representation of the correlation between two variables. Some of the indicators in the experiment have an interaction relationship, and the Pearson correlation value is chosen to calculate the degree of correlation between different human physical characteristics affecting Alzheimer's disease, and the Pearson correlation value expression is shown below [3]. f(x, y) = ∑ (Xa − X̅)(Ya − Y̅)t a=1 √∑ (Xa − X̅)2t a=1 √∑ (Ya − Y̅)2t a=1 In the equation, f(x, y)represents the similarity between the two variables X and Y, a represents the atℎ sample of a certain indicator, t is the total number of samples, and X̅ and Y̅ represent the values of two variables, X and Y, respectively. Pearson correlation values f(x, y) always fall between -1 and 1. When 0.8