• 보건행정학회지
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• 제23권1호
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• pp.78-89
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• 2013

This study empirically analyze efficiency and productivity changes of public hospitals of Korea using data envelopment analysis/Window model and global Malmquist indices model. We use the ten-year data from 2001 to 2010 of 30 regional public hospitals listed database from the Association of Korean Regional Public Hospitals. The main focuses are to reveal whether the technical inefficiency are improved as time goes by, and efficiency and productivity are affected by environmental factors. The results can be summarized as follows. First, the efficiencies of public hospitals rise in trend as time passes. Second, regional public hospitals show the different average efficiencies according to their regional type, hospital type, operational type, medicaid type, and demand and supply conditions by Mann-Whitney U-tests. Third, technical efficiency changes mainly contribute to 4.4% annual average growth rate of productivity of regional public hospitals during that period. Our findings have some policy implications. It is confirmed that there exist some environmental inefficiencies, and those inefficiencies can not be overcome through just improving the inner management system. Thus, policy and institutional changes are necessary for regional public hospitals to improve efficiency and productivity overall.

• 정보보호학회논문지
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• 제20권3호
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• pp.79-91
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• 2010

디지털 포렌식 수사에 있어 시간 정보는 중요한 요소이다. 윈도우즈의 NTFS(New Technology File System) 환경에서 획득할 수 있는 파일의 시간 정보는 생성, 수정, 접근, MFT entry 수정 시간이며 이는 파일의 복사나 이동, 이름 변경 등의 사용자의 행위에 따라 특징적으로 변경된다. 이러한 시간 변경 특징은 사용자의 데이터 이동 및 데이터 변경 등의 행위 분석에 활용할 수 있다. 본 논문에서는 윈도우즈 운영체제 별로 사용자의 행위에 따른 파일이나 폴더의 시간 변화를 분석하여 이를 바탕으로 시스템 분석시 사용자의 행위를 유추할 수 있도록 한다.

• 가족자원경영과 정책
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• 제21권4호
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• pp.35-59
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• 2017

The purpose of this study was to explore the changes in adolescents' time use and time famine between 2004~2014. The data sources were the Time Use Surveys, which were conducted by the Korea National Statistical Office in 2004 and 2014. A total of 15,386 time diaries (9,008 from 2004, 6,378 from 2014) from adolescents aged between 10 and 18 were analyzed. Descriptive statistics, chi-square, t-test were used for the statistical analyses. The main findings were as follows: First, the necessary time of adolescents was more in 2014 compared to 2004. In particular, adolescents' sleeping time increased on Saturdays. Second, on weekdays and Saturdays, the school hours of adolescents was less in 2014 compared to 2004. But extra school hours of adolescents were more on Saturdays. Third, adolescents had more leisure time on Saturdays but less leisure time on Sundays in 2014 than 2004. Fourth, the average time famine score was lower in 2014 compared to 2004. Even so, the score for high school students was higher than 3 in 4 point Likert scale. This study provides a data-base on the well-being of adolescents and the education policies that affect them.

• 가정과삶의질연구
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• 제20권1호
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• pp.17-31
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• 2002

The purpose of this study is to investigate the effects of home informatization on the family resource management. For this purpose we analyze the level of home informatization focused on the Internet use and it's effects on the family resource management through time management and financial management. Data were collected from 582 housewives who use the Internet at home. The results show that home informatization through the Internet use has changed family resource management totally. It contributes to improve planning and efficiency of resource management, but simultaneously it causes the imbalance of resource management. And the Internet use of housewives also affects time allocation and household expenditure. These changes depend on socio-demographics variables, home informatization related variables, and personal resource variables. The results show that the ability to manage time and finance have much more importance to improve the level of planning and efficiency and to decrease the level of imbalance in managerial subsystem. The results of this research suggest several implications for public policy.

• 한국지능정보시스템학회:학술대회논문집
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• 한국지능정보시스템학회 2004년도 추계학술대회
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• pp.203-210
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• 2004

Due to the explosion of e-commerce, recommender systems are rapidly becoming a core tool to accelerate cross-selling and strengthen customer loyalty. There are two prevalent approaches for building recommender systems - content-based recommending and collaborative filtering. Collaborative filtering recommender systems have been very successful in both information filtering domains and e-commerce domains, and many researchers have presented variations of collaborative filtering to increase its performance. However, the current research on recommendation has paid little attention to the use of time related data in the recommendation process. Up to now there has not been any study on collaborative filtering to reflect changes in user interest. This paper proposes dynamic fuzzy clustering algorithm and apply it to collaborative filtering algorithm for dynamic recommendations. The proposed methodology detects changes in customer behavior using the customer data at different periods of time and improves the performance of recommendations using information on changes. The results of the evaluation experiment show the proposed model's improvement in making recommendations.

• 한국컴퓨터정보학회논문지
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• 제28권9호
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• pp.159-165
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• 2023

본 연구는 공공기관 경영 효율성의 시계열적 변화 양상을 살펴보고, 이를 통해 재무적 성과와의 관련성을 검증해보고자 한다. 구체적으로 정부의 경영평가 결과에 따라 상위 그룹과 하위 그룹으로 구분하고, 평가시점 이전 그룹별 경영 효율성이 어떻게 변화하였는지를 살펴보았다. 경영효율성은 공공기관 경영정보 공개시스템의 자료를 이용하여 자료포락분석을 통해 측정하였다. 본 연구의 결과는 다음과 같다. 첫째, 경영평가 결과 상위 그룹에 속한 기관의 경영 효율성은 증가하는 방향으로 변화하였으나, 하위 그룹에 속한 기관의 경영 효율성은 감소하는 방향으로 변화하였다. 둘째, 경영평가 결과 상위 그룹에 속한 기관은 하위 기관에 속한 기관에 비해 상대적으로 높은 경영 효율성을 나타내었다. 이러한 결과는 공기업의 경영 효율성이 경영평가 결과, 즉 재무적 성과와 관련이 있음을 의미한다. 본 연구의 결과는 경영 효율성을 증대시킴으로써 공공기관의 재무적 안정성을 확보하고자 했던 정부의 개혁 전략이 유효하게 작용할 수 있음을 시사한다.

• 산업융합연구
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• 제2권2호
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• pp.127-147
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• 2004

This paper examines the time-series relations among expected return, risk, and book-to-market(B/M) at the portfolio level. The time-series analysis is a natural alternative to cross-sectional regressions. An alternative feature of the time-series regressions is that they focus on changes in expected returns, not on average returns. Using the time-series analysis, we can directly test whether the three-factor model explains time-varying expected returns better than the characteristic-based model. These results should help distinguish between the risk and mispricing stories. We find that B/M is strongly associated with changes in risk, as measured by the Fama and French(1993) three-factor model. After controlling for changes in risk, B/M contains little additional information about expected returns. The evidence suggests that the three-factor model explains time-varying expected returns better than the characteristic-based model.

• Journal of Communications and Networks
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• 제10권3호
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• pp.258-267
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• 2008

In this paper, we examine what changes the next-generation wireless communication systems will experience in terms of the technologies, services, and networks and, based on that, we investigate how the inter-cell interference management should evolve in various aspects. We identify that the main driving forces of the future changes involve the data-centric services, new dynamic service scenarios, all-IP core access networks, new physical-layer technologies, and heavy upload traffic. We establish that in order to cope with the changes, the next-generation inter-cell interference management should evolve to 1) set the objective of providing a maximal data rate, 2) take the form of joint management of power allocation and user scheduling, 3) operate in a fully distributed manner, 4) handle the time-varying channel conditions in mobile environment, 5) deal with the changes in interference mechanism triggered by the new physical-layer technologies, and 6) increase the spectral efficiency while avoiding centralized coordination of resource allocation of the users in the uplink channel.

• 한국건축시공학회지
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• 제12권6호
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• pp.624-635
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• 2012

Construction projects, including housing, are carried out over long periods of time. According to changes to the construction period, the cost of input materials and wages also changes. Therefore appropriate management is important in order to minimize cost risks caused by fluctuations in prices. In Korea, housing units are usually sold in lots prior to construction completion. Therefore, careful management of input elements such as materials and equipment that are sensitive to price fluctuations is very important. This study deals with how the price fluctuation of materials, labor, and equipment influences the change of housing cost and seeks a way for cost management through identifying key resources sensitive to price fluctuation. As a result, a change to the housing cost index multiplies depending on cost changes of materials and labor together. Labor costs are a major factor on the housing cost index. In addition, certain types of materials and labor input to housing construction greatly influence price fluctuations. Thus, it is found that managing those main cost factors is the key for effective cost management.

• Journal of Construction Engineering and Project Management
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• 제2권3호
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• pp.8-16
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• 2012

After the 2008 global financial crisis, the construction environment in South Korea continued change in the construction environment. Construction orders in 2011 have shown a downward trend compared with the previous year. Along with these changes in the construction market, the professional capabilities of construction project managers that are perceived as important also changed after the global financial crisis. Accordingly, this study was conducted to identify the major business capabilities of the current construction project managers and to determine which of these capabilities have undergone changes in terms of the importance accorded to them after the global financial crisis, and ultimately, to derive the construction project manager capability areas that need to be strengthened according to the changes in the construction environment. The capabilities of construction project managers were surveyed at two different time points: in 2007 and in 2010. The results show that the year 2010, after the global financial crisis, an increase in the perceived important capabilities of construction project managers compared with 2007. This results the impact of the changes in the construction environment on the importance of construction project managers. This study derived the ramifications of the early identification of systems and prospects according to the changes in the construction circumstances on more efficient onsite and human resources management, by considering the appropriate capabilities of the construction project managers.