مطالب

The purpose of this paper is investigating the effect of JCPOA on the network behavior analysis of Tehran Stock Exchange indexes using the minimum spanning tree (MST) and hierarchical clustering. By simplifying a complex system, network analysis allows for the extraction of important and essential information from that system. In this paper, using network analysis the simultaneous behavior of 38 industry indexes in Tehran Stock Exchange in manufacturing, service and invest-ment sectors during 2012-2017 was investigated. These analysis included identi-fying the main indexes in the direction of moving other indexes using the MST, providing a classification using hierarchical clustering for the behavioral similarity of the indexes as well as examining the degree of integration (behavioral similarity) of market indexes over time. The results showed that investment, automobile, industry and medicine indexes in the research period had a major role in guiding other indexes and indexes can be classified into six groups in terms of behavioral similarity. The market has also been moving toward integration of indexes since early 2015 and beginning the executive steps of Joint Comprehensive Plan of Action (JCPOA). This reflects the investors' hope for the promotion of all indexes.

Several theories have been presented about the corporate capital structure; some researchers believe that the structure of capital and firm value depend on each other. Moreover, others believe that the firm value is not influenced by any changes in the structure of capital, and with the change in the structure of capital, the value of the firm remains constant. The present research studies the historical theories of capital structure and presents the classification of existing theories in terms of the optimal capital structure. This classification is subdivided into two categories: the presence of an optimal capital structure and the absence of an optimal capital structure. With the historical review of theories of capital structure and the presence of an optimal capital structure or the lack of an optimal capital structure, it seems that none has been a complete model and so far, no one has been able to provide an optimal capital structure. In this research, from the system dynamics approach and using VENSIM software, the capital structure and share price of the company have been studied and the results of model simulation with real data are to ensure the correct performance of the model behavior. And the results show that financing through debt in the capital structure of the company has a significant effect on the debt cost rate and capital cost rate and does not have a significant effect on stock prices. Finally, the share price shows little sensitivity to the company's financial structure.

The aim of this paper is to develop the model of international networking. Based on purpose, this is a basic research. This study used a systematic review method to gather data for identifying, collecting and analyzing the different dimensions and components and the propositions related to international networking. The statistical population is all the research in the area of international networking, which covered by the Scopus database in the period of "open start date (not specified the start date) until the end of January 2021". The search date in this database is January 30, 2021. This research used keywords related to international networking terms in the "Title" and in the subject area of ​​"Business, Management, and Accounting" and document type, limited to "Article" to identify the research on international networking. This search yielded 112 articles. In the following step, after reviewing the abstract of the above-mentioned articles and, applying other indicators, 47 articles remained. This research coded the components and dimensions of international networking in these articles, and classified them into three categories of antecedents, processes and consequences, and, finally, identified the gaps of the previous research on the concept of international networking as well as provided research suggestions for future researchers.