• Journal of Navigation and Port Research
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• v.39 no.6
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• pp.507-514
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• 2015

The purpose of this study is to analyze the efficiency of resident companies in port hinterland logistics that are currently operating. The subjects of the efficiency analysis include 13 logistics hinterland resident companies in Incheon Port and Busan Port. Investment amounts, area, and number of employees were selected as input variables, and volume and sales amounts were selected as output variables. As for the efficiency analysis methods, traditional CCR and BCC models were applied. To overcome the limits of these models, a super-efficiency model and a Super-SBM model were also applied. According to the super-efficiency model analysis, the mean was 0.777 and the standard deviation was 0.54, indicating an approximate 33% difference of efficiency among the companies. According to the Super-SBM model analysis, the mean was 0.649 and the standard deviation was 0.489. When considering residuals in the super-efficiency model, the average efficiency score among the companies decreased by approximately 13%. This means that the efficiency score decrease of DMU, where non-radial residuals exist at about 18% on average. Examining the inefficiency of the inputs, the inefficiency of the number of employees turned out to be largest at -45%, compared to 'area' at -33% and 'investment amount' at -33%.

• Communications for Statistical Applications and Methods
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• v.4 no.2
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• pp.411-419
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• 1997

본 연구에서는 확률화응답모형이 가지는 두가지 한계에 대하여 고찰하였다. 첫째 민감한 속성을 갖는 모비율의 추정시 모비율 $\pi_A$가 매우 작은 값일 경우, 즉 희귀속성일 경우 확률화응답모형을 적용하게 되면 비밀보장의 효과를 감안한다고 해도 직접질문법에 비해 비효율적일 수 있음을 지적하였다. 둘째로 비밀보장에서 오는 이점과 그로 인한 효율의 손실이라는 서로 상충되는 면을 객관적으로 고려하는데 있어서 한계가 있음을 지적하였다.

• The Korean Journal of Applied Statistics
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• v.28 no.6
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• pp.1113-1120
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• 2015

We propose a multi-proportions randomized response model by stratified simple random sampling for surveys of sensitive issues of a polychotomous population composed of several stratum. We also systemize a theoretical validity to apply multi-proportions randomized response model (Abul-Ela et al.' model, Eriksson's model) to stratified simple random sampling and derive the estimate and its dispersion matrix of the proportion of sensitive characteristic of population using the suggested model. Two types of sample allocations (proportional allocation and optimum allocation) are considered under the fixed cost. In efficiency, the Eriksson's model by stratified sampling are compared to the Abul-Ela et al.' model.

• Journal of the Korean Society for information Management
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• v.15 no.1
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• pp.129-148
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• 1998

The objective of this study is to develop a useful relevance feedback retrieval technique that can be applied to the current Boolean retrieval system. A feedback retrieval technique based on user model is recommended here to achieve this objective. To prove the usefulness of this feedback retrieval technique, two enhanced Boolean retrieval models including DNF model and P-norm model were evaluated first through retrieval effectiveness experiments. After selecting DNF model as the retrieval model, two feedback retrieval experiments were performed using initial and extended user models. It is proved that the feedback retrieval based on user model can greatly enhance the effectiveness of a Boolean retrieval system with a small modification.

• Korean Journal of Construction Engineering and Management
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• v.6 no.1 s.23
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• pp.151-161
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• 2005

This paper analyzes the technical efficiencies of 38 Korean engineering and construction firms and the efficiency changes from 1999 to 2003 using data envelopment analysis (DEA). Best practice firms in terms of technical efficiency and profit are identified. For inefficient firms, performance targets to be efficient are suggested. Technical efficiencies had been increased over the five year period, and the efficiency difference between firms had been reduced during this period. The differences in efficiency due to the differences in cooperate governance structures are statistically significant. In addition, the technical efficiency is correlated with product portfolios, degree of subcontract, rates of value added, returns on invested capital, and EBITDA.

• Proceedings of the KAIS Fall Conference
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• 2011.05b
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• pp.765-768
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• 2011

최근 건설경기의 난국 속에서 많은 건설기업들이 경영상의 어려움에 처해 있다. 본 연구에서는 코스피 코스닥 상장 건설기업들을 대상으로 ANP와 DEA 결합 모델을 이용하여 기업의 경영 효율성 분석을 실시한다. DEA 모형에 쓰이는 투입 및 산출 요소의 결정은 ANP 모형의 중요도 분석을 통하여 결정함으로써 기존의 방법보다 효율성 분석 결과의 신뢰도를 제고하였는데, 효율성 분석결과 비효율적 그룹에 대해서는 효율적 그룹으로의 이동을 위한 벤치마킹 대상과 개선을 위한 효율성 수치를 제공한다. 또한 연구의 결과로 나온 기업별 효율성과 주가와의 상관관계를 분석한다. 본 연구에서는 코스피 상장 건설기업 36곳과 코스닥에 상장된 건설기업 21곳인 총57개 기업을 대상으로 기업의 효율성을 평가하였는데, 효율성 분석결과 CCR 효율성이 1인 기업은 4개 기업, BCC 효율성이 1인 기업은 7개 기업, 규모의 효율성이 1인 기업은 4개 기업 이었으며 각각의 효율적 그룹군 기업과 주가와의 상관관계는 CCR, BCC 모형 모두에서 0.7 이상의 강한 양의 상관관계를 나타냈다.

• Journal of the Korean GEO-environmental Society
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• v.9 no.7
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• pp.61-71
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• 2008

This study investigates the lateral resistance of micro-pile system when surcharge load is acting on the back of retaining wall. Both laboratory experiments and numerical analysis were performed. The experimental retaining wall model was developed on the laboratory-sized foundation. While surcharge load was acting, the interval and length varied as experimental variables. From the investigation it is known that the micro-pile system can effectively control the lateral displacement which is developed on the precast retaining wall. The effectiveness became increased as the pile interval reduced and the length of pile increased. The greatest reinforcing efficiency was shown when the pile length was 0.5H and the interval was 7D.

• The Journal of the Korea Contents Association
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• v.8 no.4
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• pp.173-182
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• 2008

It is hard environment to get a profit without active invest due to the low interest. In this kind of environment, however, it is also difficult to find good company directly. So private investors is hard to succeed in comprehensive financial environment. Analyzing efficiency is necessary to enhance the competitive power of fund companies. This paper analyze the efficiency of fund company using DEA models. We evaluate the CCR and BCC efficiency and RTS(return to scale) of 33 Korean fund companies. We also suggest the fund company which can be benchmarked based on analyzed information.

• Journal of Korea Water Resources Association
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• v.32 no.5
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• pp.525-535
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• 1999

An optimal unit commitment model for efficient management of water and energy resources in a basin using combined mixed integer programming is developed. The combined mixed integer programming model is able to solve the inconsistency problem that may occur from mixed integer programming models. The technique which enables the use of conditional constraints and either-or constraints in the linear programming is also suggested. As a result of applying the combined mixed integer programming model to Lower Colorado River Basin in United States. the basin efficiency is decreased by 1.53% from the results of the mixed integer programming, while it is increased by 0.67% from the results of the historical operation. It is found that the decreased allowable error between power supplies and demands in the combined mixed integer programming causes the decreased basin efficiency.

• Journal of Korea Port Economic Association
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• v.33 no.4
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• pp.1-16
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• 2017

The total container throughput of ASEAN is expected to increase continuously with economic development. However, ASEAN port infrastructure is insufficient to handle the increasing trade volume. According to the World Economic Forum, ASEAN ports except Singapore and Malaysia are ranked in low. Participation in ASEAN port development projects can lead an increase in trade efficiency with S. Korea by improving the port infrastructure of ASEAN countries. In addition, the S. Korean port-related industry can be energized through entering ASEAN port development projects. This study, which measures the efficiency of ASEAN ports, can be used as a basic guideline for the development and the planning of the ports. This study used Data Envelopment Analysis(DEA) and Shannon's Entropy model together to measure ASEAN ports' efficiency. After measuring each DEA (CCR, I-BCC, O-BCC, SBM) weight, the efficiency of ASEAN ports is measured as reflecting each DEA weight. As a result, the ports of Singapore and Malaysia, the major ports in the world, have the highest efficiency. Further, Vietnamese ports need to raise efficiency along with increasing container throughput. Leam Chabang (Thailand), Ho Chi Minh City (Vietnam), and Tanjung Priok (Indonesia) exhibit a negative correlation between container throughput and efficiency; therefore, the ports need to improve so as to maintain competitiveness. Lastly, Cambodia, Myanmar, and Brunei, which do not have active economic development, need to improve their ports for economic development.