• Journal of the Korean Operations Research and Management Science Society
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• v.38 no.4
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• pp.35-52
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• 2013

Markowitz's portfolio selection model is used to construct an optimal portfolio which has minimum variance, while satisfying a minimum required expected return. The model uses estimators based on analysis of historical data to estimate the returns, standard deviations, and correlation coefficients of individual stocks being considered for investment. However, due to the inaccuracies involved in estimations, the true optimality of a portfolio constructed using the model is questionable. To investigate the effect of estimation inaccuracy on actual portfolio performance, we study the changes in a portfolio's realized return and standard deviation as the accuracy of the estimations for each stock's return, standard deviation, and correlation coefficient is increased. Furthermore, we empirically analyze the portfolio's performance by comparing it with the performance of active mutual funds that are being traded in the Korean stock market and the KOSPI benchmark index, in terms of portfolio returns, standard deviations of returns, and Sharpe ratios. Our results suggest that, among the three input parameters, the accuracy of the estimated returns of individual stocks has the largest effect on performance, while the accuracy of the estimates of the standard deviation of each stock's returns and the correlation coefficient between different stocks have smaller effects. In addition, it is shown that even a small increase in the accuracy of the estimated return of individual stocks improves the portfolio's performance substantially, suggesting that Markowitz's model can be more effectively applied in real-life investments with just an incremental effort to increase estimation accuracy.

• Journal of the Korean Operations Research and Management Science Society
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• v.39 no.2
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• pp.83-95
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• 2014

In this paper, we develop a portfolio selection model that can be used to invest in markets with margin requirements such as the foreign exchange market. An investment algorithm to implement the proposed portfolio selection model based on objective historical data is also presented. We further conduct empirical analysis on the performance of a hypothetical investment in the foreign exchange market, using the proposed portfolio selection model and investment algorithm. Using 7 currency pairs that recorded the highest trading volume in the foreign exchange market during the most recent 10 years, we compare the performance of 1) the Dollar Index, 2) a 1/N Portfolio which equally allocates capital to all N assets considered for investment, and 3) a hypothetical investment portfolio selected and managed according to the portfolio selection model and investment algorithm proposed in this paper. Performance is compared in terms of accumulated returns and Sharpe ratios for the 10-year period from January 2003 to December 2012. The results show that the hypothetical investment portfolio outperforms both benchmarks, with superior performance especially during the period following financial crisis. Overall, this paper suggests that a mathematical approach for selecting and managing an optimal investment portfolio based on objective data can achieve outstanding performance in the foreign exchange market.

• Journal of the Korean Operations Research and Management Science Society
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• v.39 no.2
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• pp.49-66
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• 2014

This paper studies optimal consumption and investment behaviors of an individual when risky asset returns and her income are affected by the business cycle. The investor considers the incomplete information risk of unobservable macroeconomic conditions and updates her belief of expected risky asset returns through Bayesian learning. We find that the optimal investment strategy, certainty equivalent wealth, and portfolio hedging demand significantly depend on the belief about the macroeconomic conditions.

• International Journal of Advanced Culture Technology
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• v.10 no.3
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• pp.220-225
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• 2022

The purpose of this study is to develop an e-teaching portfolio to perform a teaching portfolio of an instructor on the web. I order to carry out this study, an initial model of the e-teaching portfolio was developed through systematic literature review, and the final e-teaching portfolio was developed by selecting and applying five students, then modifying and supplementing them. The study period was from May 1 to May 20, 2022. As a result of the study, the components of the finally developed e-teaching portfolio are Step 1: Understanding oneself, Step 2: Goal setting, Step 3: Learning strategy, Step 4: Self-check. In conclusion, the program developed through this study is a convenient function that can process everything in one place by connecting the fragmented teaching results, and the developed e-teaching portfolio can promote interaction between individuals by building a community. It has possible characteristics. In order to systematically activate the e-teaching portfolio developed through this study, it is necessary to establish an online management system for systematic operation. Furthermore, an institutional device is needed to guarantee the result of the developed e-teaching portfolio. In order to continuously manage the quality of the teaching portfolio, extrinsic rewards that stimulate the instructor's intrinsic motivation should be provided.

• Journal of Engineering Education Research
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• v.8 no.4
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• pp.20-30
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• 2005

The purpose of this study is the development of SPMP(Student Portfolio Management Program) to aid performance of student program outcomes related to program educational objectives. SPMP is developed to manage accreditation conditions, student materials, academic results through system database and to provide synthetic data for engineering education through statistical process. There are three functions to construct SPMP. First, the function of student information management is organized on various input data related to academic program, resume, etc. Second, the function of accreditation condition management is identified by the evaluation of program outcomes, subject grades, etc. Third, the function of course work data management is made by the operation of the academic reports and productions. The result of this study is expected to effectively provide constructive directions for continuous management in accreditation of engineering education and to support student portfolio for submission in required application.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.4
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• pp.1551-1556
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• 2012

This study proposes an efficient portfolio selection methodology for the listed corporations in KOSPI with consideration of managerial efficiency. For each industrial sector classified by KRX(Korea Exchange), the proposed method carries out an efficiency analysis using DEA (Data envelopment analysis) approach and for the efficient corporations filtered by DEA, construct portfolio using Markowitz's Model. In order to show the effectiveness of the proposed method, we constructed annually portfolios for 4 years (2007-2010) out of 600 listed corporations in KOSPI and KOSDAQ, and proved that our portfolios are superior to benchmark portfolios in terms of rate of returns.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.9
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• pp.3849-3855
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• 2011

This study presents an efficient strategy for selecting portfolio by evaluating growth potential of a corporation based on dividend. Through preliminary experiments, we extract 4 categories to sort out prospective stocks and develop a scoring table including criteria and formulas used to calculate scores for each category. In order to show the effectiveness of the portfolio selected by scoring table, we constructed 3 portfolios for every 4 years (2007-2010) out of 927 listed companies in KRX and proved that our portfolios are superior to market portfolio in terms of rate of return.

• Journal of Distribution Science
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• v.17 no.9
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• pp.117-125
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• 2019

Purpose - We investigate how to increase consumer incentives to buy public offering funds, resulting in activating the public offering fund market. In particular, this study aims to find ways to expand diversity and to improve efficiency of public offering fund. The public fund market of Korea has been stagnant in recent years. However, the public offering fund market plays a very significant role in terms of consumer welfare. Since only a few wealthy investors can participate in the private equity market, the stagnation in the public offering fund market usually reduces the opportunity of consumer's buying funds thus ultimately affecting their future wealth. Research design, data, and methodology - To attain our purpose, the 'factor-based portfolio strategy' has been considered. It is an alternative portfolio strategy, which composites the advantages of the passive management and active management. For our empirical anaylsis, we used global stock distribution market data over the period of 1991 and 2016. Then we constructed portfolios based on firm-size, firm-value, and momentum. Finally, a regression model was set, then hypotheses were tested, analyzing the performances. Results - First, among the 15 factor-based portfolios of global, Europe, Asia-Pacific(ex Japan), US and Japan, in eight portfolios, positive excess returns are observed at 5% significance level. Further, there is another portfolio with positive excess return at 10% significance level. Second, most of the portfolios with significant excess performance show positive relationship with the market portfolio. However, the firm-value based portfolio in Asia-Pacific region shows no relationship, and the firm-value based portfolio in US shows negative relationship. Third, we confirmed that the two firm-value factor portfolios in Asia-Pacific region and US, not having positive relationship with market portfolio, provide significant excess returns. Conclusions - In this paper, we provide empirical evidences supporting that the factor-based portfolios expand the diversity of funds and improve the efficiency of investment performance. However, there is no guarantee that the efficiency will continue in the future. In addition, various constraints and costs must be considered. Nevertheless, our novel findings in the advanced financial market such as US and Asia-Pacific are very interesting and offers important implications.

• Journal of Korean Society for Quality Management
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• v.45 no.3
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• pp.427-445
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• 2017

Purpose: This paper provides a method to identify cost-effective standards by analyzing the relationships between certified company and standards. It also aims to provide a evaluation model to establish a certification portfolio strategy of institutions. Methods: By analysing the networks of certified company and certification standards, this paper developed an evaluation model of standards. The evaluation model uses an index(Certificated Standard Evaluation Index; CSEI) to assess the value of standards. Results: To verify the applicability of the evaluation model, the proposed model and the CSEL index have been applied to certification standards of Korean Standard Association. The results show that the evaluation model can effectively identify potential customers and thereby establish a certification portfolio strategy. Conclusion: The main contribution of this study is a provision of a new approach to certification portfolio strategy by evaluating the value of standards. The proposed model is expected to provide implications for the certification portfolio strategy.

• Journal of Korean Institute of Industrial Engineers
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• v.39 no.4
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• pp.260-270
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• 2013

This paper proposes a strategic portfolio model for managing performance of online games. The portfolio matrix is composed of two dimensions: financial performance and non-financial performance. Financial performance is measured by the conventional measure, average revenue per user (ARPU). In terms of non-financial performance, five non-financial key performance indicators (KPIs) that have been widely used in the online game industry are utilized: RU (Register User), VU (Visiting User), TS (Time Spent), ACU (Average Current User), MCU (Maximum Current User). Data envelopment analysis (DEA) is then employed to produce a single performance measure aggregating the five KPIs. DEA is a linear programming model for measuring the relative efficiency of decision making unit (DMUs) with multiple inputs and outputs. This study employs DEA as a tool for multiple criteria decision making (MCDM), in particular, the pure output model without inputs. Combining the two types of performance produces the online game portfolio matrix with four quadrants: Dark Horse, Stop Loss, Jack Pot, Luxury Goods. A case study of 39 online games provided by company 'N' is provided. The proposed portfolio model is expected to be fruitfully used for strategic decision making of online game companies.