• 한국초등과학교육학회지:초등과학교육
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• 제20권1호
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• pp.107-122
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• 2001

The Purpose of this study is to find the effects of the portfolio assessment on elementary students' scientific knowledge, inquiry process skill, scientific attitudes in the teaching of science. And finally the parents' response to the portfolio assessment is also investigated. In order to reach the goal of this study, the investigator developed the evaluation instrument such as an experimental report and a cumulative observation sheet for the 4th-grade Unit-1 'Light Propagation' and Unit-3 'Separating Mixtures', and then these were administered to 42 4th-grade elementary students in Inchon. Based upon the findings and within the limitations of this study, several conclusions can be drawn regarding the problems investigated. First, as the portfolio assessment offers enough information about individual student's performance, it has a highly positive effect on evaluating the students' scientific knowledges. It can also make possible to grasp the several aspects of the student's progress. Second, the portfolio assessment can be implemented without giving students any psychological pressure from testing itself. Therefore, the portfolio assessment is an effective means of appraising inquiry process skills. Third, the portfolio assessment is effective to evaluate the students' attitude toward science by means of individual records which include such aspects that is hardly found by the teacher who teaches science in the class. Fourth, as most parents showed a positive response to this portfolio assessment, it is considered to be effective method of appraising the result of teaching science at elementary school. Accordingly, this study demonstrated that the portfolio assessment is an effective method that can assess students' scientific knowledges, inquiry process skills, and scientific attitudes gained from science teaching-learning. Therefore, it is necessary to implement the portfolio assessment to other grade students as well in the following study where teacher may give more encouragements and suggestions to sti dents for the better learning motives. Also teachers should suggest more definite evaluation criteria to students so that they may improve the students' self and peer evaluation skills.

• 한국정보시스템학회지:정보시스템연구
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• 제28권3호
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• pp.203-225
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• 2019

Purpose The purpose of this study is to empirically verify an ePortfolio success model which shows the structural causal relationships among the basic modeling constructs. We developed the success model based on DeLone and Mclean(2003) from IS perspective and on Balaban et al(2013) from ePortfolio perspective. And we are focused on the success of ePortfolio system designed for college students and professors. Design/methodology/approach Structural equation modeling techniques were applied to data collected 375 users of the ePortfolio system, K-Folio, at least one semester during one academic year. The structural model was analyzed using a Lisrel 8.54 statistical program. Findings The followings are the findings of the study. First, the constructs of IS success model are well applied to ePortfolio for college education. Second, the proposed model which has direct causal relationships from ePortfolio's quality to performance is more significant than the D&M and Balaban's model(2013). Third, the information quality among ePortfolio quality constructs does not have effect on system usability and performance. It means that information contents' quality issued by professor or system manager is not satisfied with the students yet. Finally, by using indirect analysis of structural equation model, we found that the ePortfolio operation manager should focus on ensuring system maintenance activities and providing fast and accurate services for improving ePortfolio performance.

• 정보학연구
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• 제9권3호
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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.

• 공학교육연구
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• 제13권1호
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• pp.70-77
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• 2010

본 연구는 학생포트폴리오 작성 경험을 분석함으로써 학생포트폴리오의 교육적 가치 및 작성지도의 방향을 제시하고자 한다. 연구의 목적을 달성하기 위해 질적연구를 수행하였는데, 포트폴리오에 대한 문헌연구를 토대로 인터뷰 문항을 구성하고 인천광역시 소재 I 대학의 학생 9명을 대상으로 인터뷰를 실시하였다. 인터뷰에 응한 학생들은 교내 학생포트폴리오 경진대회의 수상자 11명 중 일부로써 인터뷰 전 과정을 녹취하고 이를 전사하여 분석하였다. 인터뷰 결과 대부분의 학생들은 공학교육인증 평가를 위해 타의적으로 학생포트폴리오 작성을 시작하였으나 학생포트폴리오 작성이 필요하며 저학년 때부터 작성하는 것이 바람직하다고 인식하였다. 학생포트폴리오 작성시의 어려움으로는 자료 관리의 미비로 자료의 부족을 손꼽았으며 포트폴리오 자체에 대한 인식이 낮아 표준 양식을 제공해 준다고 하더라도 어떻게 작성해야 할지 어려워하고 있었다. 학생들은 학생포트폴리오를 작성함으로써 자기 반성의 기회를 갖고 기록의 중요성을 인식하며, 미래에 대한 준비를 할 수 있는 기회를 갖게 되었다. 이러한 과정을 통해 학생들은 또 다른 활동이나 능력 향상을 위한 동기가 생겨나고 자신감을 획득하게 되며, 꾸준한 포트폴리오 작성 과정으로 인해 문서작성 능력의 향상을 인식하게 되는 등 다양한 긍정적인 효과를 경험할 수 있었다.

• 한국정보통신학회논문지
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• 제15권3호
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• pp.501-509
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• 2011

본 논문은 국가 정보통신(IT)분야 연구개발(R&D)사업에 대한 전략과제를 선정하기 위한 모형을 제시한 것으로 우리나라 정부의 New IT R&D정책인 Smile-curve에 맞는 전략과제 선정을 위해 포트폴리오 모형을 적용하였으며, 포트폴리오 모형 중에서 정부정책의 효과적 반영을 위해 일반적인 R-R(Risk-Return) 포트폴리오 모형을 국가 R&D 체계에 맞게 개발 적용하였다. 또한, R-R 포트폴리오 모형의 평가항목 중 평가항목의 객관성 확보를 위해 TRM(기술로드맵)과 TLS(기술수준조사)자료의 항목을 사용하였으며, AHP(계층화분석)를 통하여 국가전략성, 시장성, 기술성 등 평가항목별 가중치를 설정함으로써 국가 R&D전략과의 연계성을 강화하였다. 또한, 본 모형을 국가 IT R&D 전략과제 선정에 적용한 결과 의미 있는 검증값이 나왔으며, 사업선정단계에서부터 사업의 불확실성을 줄이고 성공률을 높이는 전략과제를 선정하는데 기여하고자 한다.

• Asia pacific journal of information systems
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• 제27권4호
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• pp.233-244
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• 2017

IT portfolio, meaning the ratio of investment with four different purposes of IT, is widely used for evaluating the adequacy of investment and its performance within firms. Despite of such a useful framework looking at investment on IT, IT portfolio in agriculture industry seems to be differentiated from other industries. In this study, we compared IT portfolios of farms: grain, field fruit and vegetable, greenhouse fruit, greenhouse vegetable, beef cattle and pig. We classified farms by their return on equity (ROE) in order to analyze the relationship between IT portfolio of each crop and performance. Then, we found patterns of IT portfolios of top-performance farms compared to all farms for each agricultural product. Lastly, peculiarities of each crop are interpreted and discussed to find out top-performance farms' IT investment patterns. From our study, it could be inferred that monotonous IT investments may not be as effective.

• 한국임상약학회지
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• 제24권2호
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• pp.90-97
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• 2014

Learning portfolio is a collection of evidence that learning has taken place. It has gained its reputation as a useful assessment tool in the education of health professionals. The purpose of this study is to describe the pharmacy students' experiences and perceptions upon the introduction of a learning portfolio into the Introductory Pharmacy Practice Experience course. Methods: Fifty five students from one pharmacy school who used a learning portfolio to document their progress in the IPPE course participated in 16-item questionnaire exploring opinions and experiences of learning portfolio preparation, assessment, and personal and professional development and reflection. Results: Most students agree that a learning portfolio is a valuable tool in promoting self-directed and reflective learning. However most of them (46/55) also feel developing a portfolio is time-consuming, and when compared to their effort, an appropriate reward has not been given. Conclusion: To make the use of learning portfolios successful students should receive clear guidelines on their purpose, content and structure. Also the assessment criteria should be provided before the introduction of learning portfolio and their effort in developing learning portfolio should be rewarded.

• 한국경영과학회지
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• 제38권4호
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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.

• Industrial Engineering and Management Systems
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• 제13권4호
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• pp.442-448
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• 2014

Portfolio optimization in the presence of estimation error can be stabilized by incorporating norm-constraints; this result was shown by DeMiguel et al. (A generalized approach to portfolio optimization: improving performance by constraining portfolio norms, Management Science, 5, 798-812, 2009), who reported empirical performance better than numerous competing approaches. We extend the idea of norm-constraints by introducing a powerful enhancement, grouped selection for portfolio optimization. Here, instead of merely penalizing norms of the assets being selected, we penalize groups, where within a group assets are treated alike, but across groups, the penalization may differ. The idea of groupwise selection is grounded in statistics, but to our knowledge, it is novel in the context of portfolio optimization. Novelty aside, the real benefits of groupwise selection are substantiated by experiments; our results show that groupwise asset selection leads to strategies with lower variance, higher Sharpe ratios, and even higher expected returns than the ordinary norm-constrained formulations.

• 한국콘텐츠학회논문지
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• 제8권5호
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• pp.260-267
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• 2008

포트폴리오는 장기간에 걸친 학생의 학습과 성장을 타당하게 평가할 수 있는 방법을 제공하며 자기반성을 통하여 실제적 학습을 가능하게 한다. 하지만 포트폴리오의 운영 실태에 따르면 실시에 있어 시간 소요, 장기 보관의 어려움 등으로 인하여 일회적이고 평가를 위해 형식적으로 운영되고 있는 실정이다. 본 논문에서는 학생의 학습 과정과 성장 결과를 총체적으로 파악한 후에 포트폴리오 실시에 따른 물리적 제약요인을 줄이기 위해 학습과 평가를 통합한 e-포트폴리오를 설계한다. 설계한 e-포트폴리오 모델의 효과성을 검증하기 위해 블로그를 기반으로 e-포트폴리오를 운영한 결과 학생들의 학업 성취도에 유의미한 변화가 있었으며 교사를 대상으로 한 활용 가능성도 긍정적으로 나타났다. 따라서 본 연구에서 제안한 e-포트폴리오 운영으로 학습과 평가 기능이 상호 작용적으로 통합된 보다 진전되고 의미 있는 포트폴리오 활용 교육이 기대된다.