درخت حوزه‌های تخصصی

Data mining is known as one of the powerful tools in generating information and knowledge from raw data, and Clustering as one of the standard methods in data mining is a suitable method for grouping data in different clusters that helps to understand and analyze relationships. It is one of the essential issues in the field of investment, so by using stock market clustering, helpful information can be obtained to predict changes in stock prices of different companies and then on how to decide the correct number and shares in the portfolio to private investors and financial professionals' help. The purpose of this study is to cluster the companies listed on the Tehran stock exchange using three methods of K-means Clustering, Hierarchical clustering, and Affinity propagation clustering and compare these three methods with each other. To conduct this research, the adjusted price of 50 listed companies for the period 2019-07-01 to 2020-09-29 has been used.  The evaluation results show that the obtained silhouette coefficient for K-means Clustering is higher and, therefore, better than other methods for stock exchange data. In the continuation of the research, calculating the co-integration of stock pairs that have the same co-movement with each other were identified, and finally, clusters were compiled using the t-SNE method.

Performance evaluation, as a tool to know the degree of success of organizations in achieving predetermined goals and a factor in managers' decisions, has been one of the constant needs of organizations. The purpose of this research is to identify performance evaluation indicators and explain the appropriate performance evaluation model in Macro government organizations such as Jam Petrochemical Company. This research is based on the purpose of applied research and also based on the research method with a mixed or combined approach with a sequential exploratory strategy. The required data were collected through qualitative research (interview) and quantitative research (questionnaire). In the quantitative part, the current research can be considered as a non-experimental (descriptive) type of research and a survey type. To analyze the data of the questionnaire, this research has been done in four phases, the first phase is to identify and rank the strengths and weaknesses of Jam Petrochemical Company, and the second phase is to use a Delphi test to identify indicators that are effective in evaluating the performance of Jam Petrochemical Company. The third phase is exploratory factor analysis and determining Dimensions of performance evaluation in Jam Petrochemical Company and finally the fourth phase of structural equations and path analysis. The results of the research showed that considering that the T-statistic for all variables is more significant than 1.96 and also considering the positiveness of the path coefficients, the variables (scientific observation, technology and technology, financial management, managers' responsibility, infrastructure management, management and leadership and human resources) are among the factors that make up the performance evaluation system in Jam Petrochemical Company.