• 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.

• The Journal of Asian Finance, Economics and Business
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• v.1 no.2
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• pp.31-37
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• 2014

The portfolio selection is one of the most important and vital decisions that a real or legal person, who invests in stock market, should make. The main purpose of this article is the determination of the optimal portfolio with regard to relations among stock returns of companies which are active in Tehran's stock market. For achieving this goal, weekly statistics of company's stocks since Farvardin 1389 until Esfand 1390, has been used. For analyzing statistics and information and examination of stocks of companies which has change in returns, factors analysis approach and clustering analysis has been used (FC approach). With using multivariate analysis and with the aim of reducing the unsystematic risk, a financial portfoliois formed. At last but not least, results of choosing the optimal portfolio rather than randomly choosing a portfolio are given.

• Proceedings of the Korea Technology Innovation Society Conference
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• 2017.05a
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• pp.357-391
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• 2017

In this study, we suggest a new perspective on the linkage between alliance portfolio diversity and innovation performance based on a contingency approach. Using a longitudinal data set on alliance portfolios and patents of 182 firms in the U.S. manufacturing industries, we examined that alliance portfolio diversity has a U-shaped relationship with firm-level innovation. Internal value creation capabilities in terms of routine and ability are found to moderate the relationship between alliance portfolio diversity and innovation performance: Organizational search routine strengthens the relationship of alliance portfolio diversity and innovation performance while technological capabilities weaken and flip the relationship.

• The Journal of Information Technology
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• v.9 no.3
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• pp.77-89
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• 2006

The event study analyzes returns around event date at a time. Event study provides estimation periods and cumulative returns. Stock split announcements are generally associated with positive abnormal returns. It is important to investigate the responses of stocks to new information contained in the announcements of stock splits. So It is important to study the long term performance in the case of Stock Split. This Study forced to two approach method in evaluating the performance, the event time portfolio approach and calendar time portfolio approach. The event time portfolio approach exists the CAR model, BHAR model and WR model. And the calendar time portfolio approach has the 3 factor model, 4 factor model, CTAR model, and RATS model.

• Journal of Fisheries and Marine Sciences Education
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• v.20 no.2
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• pp.236-248
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• 2008

This study has explored the elements of e-teaching portfolio for enhancing teaching expertise in higher education. This study is carried out through the literature review and expert's focus group interview. As the result of this study, seven elements of e-teaching portfolio for enhancing teaching expertise in higher education have been found. First, 'personal background' include curriculum vitae, course responsibility, and other educational activities. Second, 'teaching philosophy' include the principals on teaching and learning, statements of teaching philosophy. Third, 'learning environment' include the characteristics of students, the previous learning contents, and physical environment. Forth, 'course contents and methods' include teaching strategies and instructional materials, Fifth, 'instructional evaluation' includes the principals of evaluation and the examples of learning outcomes. Sixth, 'endeavor for improvement of instruction' include evidence of activity for teaching improvement and instruction feedback from peer and students. And e-teaching portfolio also includes research career and awards history element.

• Korean Journal of Child Studies
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• v.21 no.3
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• pp.107-117
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• 2000

This study examined a portfolio scale for the assessment of the writing of 295 kindergarten children. The data were analyzed by Spradley's Developmental Research Sequence(DRS), using qualitative methods. Results showed that the writing portfolio scale for 4-year-olds includes "a word or write a children's name" "picture or word with shape of letters" and "scribbling or zig-zag". The writing portfolio scale for 5- and 6-year-olds includes "invented spelling" "write according to sound" and "omitted letters" "write a good hand". The writing portfolio scale for 4-, 5-, and 6-year-olds reflects their writing experience in daily life.

• The Journal of Korean Association of Computer Education
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• v.17 no.2
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• pp.87-95
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• 2014

e-Portfolio is a useful tool that enhances students' learning competency. This paper introduces 'K-folio' which is an e-Portfolio system. K-folio is currently being implemented throughout campus. K-folio is designed to apply the theoretical framework for college level e-Portfolio. We chose RAD(Rapid Application Development) as our development method which we designed to gradually improve system's capability and usability by reflecting and implementing the suggestions of students and instructors. This paper has the following contributions: first, it proposes the e-Portfolio implementation model that is more applicable to the college environment. second, the study identifies RAD as the most suitable method for e-Portfolio development. third, it mentions important technical implications regarding the development and operation for their e-Portfolio.

• Journal of Korean Elementary Science Education
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• v.26 no.4
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• pp.372-384
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• 2007

The purposes of this study was to analyze qualitatively changes in students' experience and perceptions in relation to studying science using portfolios and any resultant effects on the portfolio itself. Five fourth-grade elementary students from one small city participated in this study. Data was collected through interviews as well as through student portfolios containing the science content matter of two units over two weeks. Observational diaries recorded by a teacher were also used to test the reliability of data collection. All interviews with students were transcribed to develop a suitable network to categorize students' responses. Students' portfolios were analyzed in order to reveal their essential characteristics in combination with their teacher's observational diaries. The results were as follows. First, student perceptions of their portfolios were categorized into three different levels; superficial, extended, and moderate perceptions. The changes in perception could also be divided into three levels; consistent-superficial, unstable, and a progressive-extended pattern. Second, the experience of students with their portfolio were investigated in terms of the following; successfully completing the elements of the portfolio, development of evidence, interaction with peers, teachers, and parents, and the standards of evaluation used for the portfolios. Third, the perceptions and experience of working on the portfolio by students had a number of direct effects on the way in which students actually created and developed their portfolios. Finally, students with positive attitudes towards their portfolios actively participated in the portfolio experience and finally understood what it meant completely. However, students with negative attitudes regarding portfolio based work, did not leave the experience with any heightened awareness of the utility or indeed, purpose of portfolio based work.

• Journal of The Korean Association of Information Education
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• v.10 no.1
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• pp.1-12
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• 2006

Sometimes the quantitative evaluation method does not explain students' full capacity in educational fields. In this point of view, performance assessment has been adapted widely since the assessment provides a comprehensive qualitative evaluation as well as quantitative evaluation. Portfolio is one of the most effective methods in performance assessment. However, the portfolio requires longer time in evaluation, physical space for storing data gathered from students. Electronic portfolio can overcome the above disadvantages of the traditional portfolio and increase students' ICT application capacity. The purpose of this study is to develop electronic portfolio assessment processing model and present concrete activities for each stage in the model. Our model consists of four stages, Preparation, Activity, Evaluation, and Application, respectively. Especially, our model is designed to provide different activities for students and teachers in each stage. Our model is expected to provide a good guidance to students, teachers and parents in understanding and utilizing portfolio assessment. Particularly our model will provide the comprehensive guidance to teachers in assessment process.

• The Journal of the Korea Contents Association
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• v.13 no.11
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• pp.48-58
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• 2013

The stock market is constantly changing and sometimes a slump or a sudden rising in stocks happens without any special reason. So the stock market is recognized as a complex system and it is hard to predict the change on stock prices. In this paper we consider the stock market to a network consisting of stocks. We analyzed the dynamics of the Korean stock market network and evaluated the changing of the correlation between shares consisting of the time series data of 137 companies belong to KOSPI200. Our analysis shows that the stock prices tend to plummet when the correlation between stocks is very high. We propose a method for recommending the stock portfolio based on the analysis of the stock market network. To show the effectiveness of the recommended portfolio, we conducted the simulated stock investment and compared the recommended portfolio with the efficient portfolio proposed Markowitz. According to the experiment results, the rate of return of the portfolio is about 10.6% which is about 3.7% and 5.6% higher than the average rate of return of the efficient portfolio and KOSPI200 respectively.