مطالب

As a trading strategy, pairs trading is performed based on the arbitrage opportunities extracted from statistical models. It is an outcome of the distance between an asset pair and the equilibrium state. Consequently, selecting a pair with the potential to form long-term relationships and reverting to the mean is the main challenge associated with pair trading. Cointegration is one of the most famous statistical tests for selecting a pair's trading. The present study uses Empirical Mode Decomposition (EMD) to decompose the time series of an asset pair price into its constituent elements (intrinsic mode functions). This study examined the property of cointegration across different levels and the corresponding levels of 2- time series to find the cointegration pairs in different decomposition levels and finally examine the resulting profitability. To this end, the profitability of the pairs trading system related to 14 stocks of the Tehran Stock Exchange throughout 2012-2021 was investigated based on EMD. The results showed that the outputs are pretty noticeable for the first level of decomposition (the first intrinsic mode function), and the number of trading opportunities increased by more than two times compared to the normal pair trading with cointegration; the daily returns increased by four times; and the Sharpe ratio increased by about two times compared to the normal pairs trading. The system formed based on the second mode function also outperformed the normal cointegration, and the performance of the third intrinsic mode function is almost on par with that of cointegration. Moreover, the mean transaction duration decreased remarkably in the first and second mode functions.

Corporate integrity is considered as part of the company's development strategies, which in the long run can lead to the increased firms' financial transparency to stakeholders. The purpose of our study is to present a corporate integrity model and, then to investigate its effect on firms' information asymmetry. In this study, to measure the corporate integrity, we use Meta-synthesis and Delphi analysis in the qualitative part. Then, in the quantitative section, the corporate integrity questionnaires were sent to the managers of the sample firms. Subsequently, a total of 138 questionnaires were completed and sent back, which were used as the final samples for analysis. In addition, information asymmetry is measured using the three different proxies, namely bid-ask spread, turnover, and Amihud illiquidity measure. Our findings show a significant and negative effect of corporate integrity on information asymmetry. This results suggest that corporate integrity, by promoting behavioral values based on truthfulness and commitment, the structures will enhance the corporate governance mechanisms and, thereby, firstly motivate the managers to reduce the agency gap and, secondly, implement a more effective level of the supervisions on the firm's performances in front of the stakeholders by accelerating the circulation of information and giving timely and reliable feedback to the stakeholders. This is the first study that presents a corporate integrity model through qualitative analysis and then, investigates the effect of corporate integrity on firms' information asymmetry. Therefore, our study can contribute to the extant literature of this context.

Purpose: The e-learning is one of the new educational methods that can create a competitive advantage for organizations and countries. Therefore, the current research was conducted with the aim of a comparative study of e-learning in the countries of England and South Korea. Methodology: This study in terms of purpose was applied and in terms of implementation method was review. The current research population was the e-learning system of countries of England and South Korea, which these two educational systems were examined in terms of similarities and differences. For this purpose, e-learning in the countries of England and South Korea were investigated and the data obtained from e-learning in both countries were compared. Findings: The findings showed that both countries of England and South Korea in e-learning emphasized on the experience e-learning by creating periodic programs and policies and appropriate to the time, creating two formal and informal education methods, increasing the skills of students and parents about using educational resources, raising media literacy, providing high-quality, free, diverse, attractive and easy-to-use educational content, using the full capabilities of four communication screens of tablets, smart phones, internet TVs and computers for learning, open and collaborative environment for creating creative ideas by the audience, participation in production with curriculum organizations and universities, encouraging and financial support from top creators of educational programs and updating the educational programs and learning practices. On the contrary, in the e-learning of England country emphasized on the creation of content of learning resources suitable to their different nationalities and interests, investing on music videos with appropriate orientation to them, convergence and integration of learning resources and updating and transferring them through the internet, special attention to formal learning programs for under 19 years and using the successes and personal thoughts of users, but in the e-learning of South Korean country emphasis on the financial support from domestic products for the growth of the local content industry in the field of educational documentaries, sharing international educational content by signing a contract with YouTube and holding international conferences and festivals for global interaction with the creators of educational documentaries. Conclusion: Despite the similarities between e-learning in two countries of England and South Korea, there are differences between e-learning in the two countries. According to the results, the educational planners of Iran country, while paying attention to the cultural context, can provide the basis for better e-learning in the country.