درخت حوزه‌های تخصصی

Purpose: The main purpose of this study is to design and evaluate a book recommender system in digital and public libraries. The solution has been provided by receiving and reviewing the preferences and experiences of users and profile information and studying the background of each user, as well as considering groups of features recorded in the recommendation process. Method: This research is applied in terms of purpose and survey method. The statistical population studied in this research consists of 263 questionnaires of users and 30 questionnaires of librarian experts. In order to find similarity between users and books, clustering and grouping have been used. Findings: There are two criteria for grouping: users grouping that can be used on the three indicators of age, gender, educational level, and thematic classification of books can be based on scope, branch, and sub-category. In analyzing the data in the descriptive statistics section, Excel software is used and in the analytical section, SPSS software. Findings indicate that the accuracy criterion has been improved by calculating MAE and RSME in the proposed method compared to the basic method in this field. The results also showed that classification can have a significant impact on the forecast and performance of book forecasting systems. Conclusion: The evaluation of the conceptual design showed that by focusing on user characteristics and obtaining real feedback of Iranian libraries, the recommender can serve as a key and effective element in the service of the Iranian readership community and play a good role as a virtual reference librarian.

Purpose: Accurate scientific evaluation of researchers by ResearchGate network is still ambiguous. This systematic study seeks to shed some light on this issue.Methods: The study was conducted with a systematic review of the previous studies (articles or reports). The analysis of documents was performed with a targeted keyword search in the reputable Google Scholar, Emerald, and PubMed databases (without limit). Titles and abstracts (if necessary, full texts) of the number of 582 documents (Persian, English, and Spanish) were retrieved (1-10 April 2021) and studied. Then, by removing duplicate or irrelevant data, 57 independent studies were selected for meeting the main research problem of this systematic review (using the PRISMA statement). For drawing diagrams, Excel software was used.Findings: Among 57 previous independent studies  retrieved by systematic review, 30 ones, had a negative attitude towards the ResearchGate.  27 studies saw with positive approach from standpoint the concepts of "authentic measuring instrument", " presence of prominent scientists such as Nobel Prize recipients", "valid scientific content", and "having a significant relationship with the academic ranking criteria", and "compliance with the Hirsch indicator", that was identified by documentary analysis based on PRISMA statement. Studies with a positive assessment of the ResearchGate dealt with developing countries, and with a small investigated research community. Therefore, it is appropriate to act cautiously when evaluating researchers with the ResearchGate network.Originality: No similar systematic review to evaluate the ResearchGate network from the standpoint of a scientific suitable evaluation tool, has been done so far.

Financial markets play a key role in economic development, and the insurance industry as a financial institution can be the bedrock of economic growth. Thus, risk and performance appraisal are very important in the insurance industry. There are several methods for evaluate risk and efficiency in financial markets, but since the performance of insurance companies is different from other financial institutions for the risk acceptance of other organizations and individuals, it is necessary to rank factors affecting efficiency and risk in insurance companies separately based on the performance of companies prior to focus on the calculation method. This paper discussed factors affecting the financial risks of insurance companies and efficiency and their rankings using the Delphi qualitative method and collecting expert’s opinions as well as data from domestic and forign papers. The statistical population of the research is experts and specialists in the field of risk and insurance. Spss, Eviews and Excell 2013 were used to review the questionnaires and estimate the results. The results of this paper identified the factors affecting each of the risks of financial wealth, liquidity, credit, operations and efficiency, and in the ranking obtained through Friedman test, efficiency is the highest rank, followed by liquidity, operational and credit risk in the rankings.

This research aims to evaluate the effect of consumer traits, service quality, perception-based factors, customer satisfaction, and e-trust on electronic brand love and e-loyalty. In this study, a cross-sectional survey is conducted based on the questionnaire method to collect data from a sample of 300 customers of the Digikala Website in Isfahan, Iran. Structural equation modeling (SEM) is used to test the research hypotheses. According to the results, the service quality, consumer traits, and perception-based factors significantly affected customer satisfaction. Also, e-brand love had a significant impact on e-trust and e-loyalty; e-trust significantly affected e-brand love and e-loyalty, and e-brand love had a significant impact on e-loyalty. To the best of the authors’ knowledge, this research stands among the first to evaluate the factors affecting electronic brand love and loyalty. The evaluation of brand love on loyalty demonstrated that the greater the amount of love and fascination with a brand, the higher the positive effect on consumer loyalty. Overall, managers are recommended to do their best to eliminate misunderstandings and create an interest in consumers, ultimately leading to greater customer loyalty. Managers should pay more attention to brand experience dimensions, such as sensory marketing. In this regard, creating a brand community by e-retailers is very helpful.

In this paper, first, the stochastic differential equations are introduced as well as the definition and basic theories about Monte Carlo and quasi-Monte Carlo and Sobel and Halton sequences are expressed. Indeed, we introduce and use simulations under these methods to compare the efficiency of the solutions, which the results show that the approximation of the resulting Sobel sequence is much better than other stochastic methods. The comparison of the efficiency of random and quasi-random methods, the geometric Brownian movement and the price index of Tehran stock (equal weight and weight-value) is studied. The results show that the quasi-Monte Carlo method is better than other methods.

This study examines the relationship between stock liquidity and return predicta-bility of 116 publicly-traded firms in Tehran Stock Exchange (TSE). To this end, we constructed a dated-regular frequency of time series with total 40128 stock-firm observations. After calculating daily bid-ask spreads and stock returns, the observations were classified based on liquidity into three classes and the return predictability was investigated across different classes using a set of parametric tests. The results exhibit signs of return autocorrelation and non-independence over three liquidity groups. Our findings didn’t show a connection between stock liquidity and market efficiency. The Hurst exponent also revealed mean reversion of returns series across different liquidity classes. We conclude that stock liquidity doesn’t play a significant role in market efficiency and return predictability of stocks in TSE. In case of TSE as other emerging markets, due to the small num-ber of traders (the need for more trading activity) and low market making activi-ties, both the cost of trading increases and the reaction to stock price information is delayed, resulting in predictability of price /return.