• The Korean Journal of Applied Statistics
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• v.26 no.1
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• pp.49-58
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• 2013

Data envelopment analysis is a relatively new data oriented approach to evaluate the performance of a set of peer entities called decision making units which convert multiple inputs into multiple outputs. It has been extensively applied in performance evaluation and benchmarking entities such as hospitals, universities, cities, courts, and business firms. This study provides the evaluating results of the operational efficiencies of local universities using a DEA approach. In addition, we explore the difference of the efficiency between regional flagship national universities and non-flagships.

• KDI Journal of Economic Policy
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• v.15 no.1
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• pp.185-205
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• 1993

Shiller에 의하여 개발된 분산한계검증모형(分散限界檢證模型)은 간결하고 명쾌한 모형유도(模型誘導)와 강력한 검증결과(檢證結果)에 의해 주목받아 왔으나 비현실적(非現實的)인 가정(假定)들을 통한 모형설계와 검증통계량(檢證統計量)의 통계적 오류로 검증결과의 신뢰성이 의문시되어 왔다. 이러한 문제점을 제거하기 위한 Mankiw-Romer-Shapiro(MRS)모형(模型) 역시 임의변수(任意變數)의 도입으로 인한 검증력(檢證力) 저하(低下)와 고정기대수익율가정(固定期待收益率假定)의 채택으로 결합가설검증(結合假說檢證) 형태를 취하게 되는 문제점을 드러냈다. 본고(本稿)는 MRS모형(模型)의 문제점을 제거하기 위하여 먼저 Lucas의 균형자산가격모형(均衡資産價格模型)을 이용하여 고정기대수익율가정(固定期待收益率假定)을 완화하였고, 이에 의하여 구해진 변수들을 사용하여 합리적(合理的) 기대이론(期待理論)의 일반관계식(一般關係式)으로부터 새로운 검증모형(檢證模型)을 유도하였다. 1982~92년까지의 종합주가지수(綜合株價指數)와 대응하는 배당액(配當額)의 연도별(年度別) 시계열자료(時系列資料)를 가지고 검증실험을 행하여 본 결과 한국(韓國) 주식시장(株式市場)에서 효율적 시장가설은 기각되었고, 이를 통하여 관련정보(關聯情報)가 시장가격(市場價格)에 제대로 반영되지 않고 있으며, 정보(情報)의 비대칭성(非對稱性)으로 인하여 주식시장은 금융자원(金融資源)의 중개기능(仲介機能)을 효율적으로 수행하지 못하고 있음을 알 수 있었다. 따라서 한국 주식시장의 효율성을 제고하기 위하여 먼저 시장의 비효율성을 야기하는 요인(要因)들에 대한 분석(分析)과 이 분석을 통한 효율성(效率性) 장애요인(障碍要因)을 제거하는 것이 주식시장에 대한 정부정책(政府政策)의 우선순위(優先順位)가 되어야 할 것이다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.5
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• pp.826-832
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• 2015

In wireless networks, it is important to guarantee the energy efficiency and receiver fairness for satisfying service provider and customer at the same time. In this paper, we propose a resource allocation algorithm which improves energy efficiency as well as receiver fairness based on optimization techniques. In the proposed algorithm, subchannel and power are allocated to receivers iteratively in the consideration of channel state information, amount of dissipated power, and receiver rate, in order to improve energy efficiency and receiver fairness. Through simulation, we show the effectiveness and superiority of the proposed algorithm in terms of energy efficiency and receiver fairness.

• Annual Conference of KIPS
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• 2021.11a
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• pp.111-114
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• 2021

기업은 IT 를 일종의 자산으로 판단하여 IT 센터를 직접 구축하고 온프레미스 형태의 시스템을 운영했다. 그러나 경영 환경의 변화가 빨라지면서 IT 부문의 비용 효율성에 대한 압박도 커지고 있다. 클라우드 컴퓨팅을 도입하면 IT 자원을 효율적으로 활용하고 사용한 만큼 비용을 지불할 수 있어 IT 자원의 효율화가 가능하다. 하지만 무작정 클라우드로 옮기는 방식으로 인해 시스템 복잡성이 오히려 증가하고, 관리포인트 증가로 시스템 안전성을 해치는 상황이 벌어지고 있는 것도 현실이다. 신규 서비스 제공 시 기존 시스템 안전성을 해치지 않으면서 IT 자원의 효율적인 활용도 고려하는 방안으로 서비스 단위별 클라우드 컴퓨팅 도입을 검토하였다. 이 방법은 클라우드의 우수한 시스템을 사용하며, 실시간 오케스트레이션이 가능하고, 보안도 우수하다고 볼 수 있다. 기존 인프라를 유지하면서 클라우드 컴퓨팅을 구현한 하이브리드 방식으로 시스템 구축 결과 중단 없는 시스템 운영이 가능하였으며, 보안도 보다 강화된 결과를 얻었다. 향후 시스템 구축 시 온프레미스의 경우 서비스 단위로 클라우드 서버를 병행 운영한다면 운영효율성 뿐 아니라 기능성까지 만족시킬 수 있을 것으로 기대한다.

• KDI Journal of Economic Policy
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• v.12 no.4
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• pp.21-46
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• 1990

This paper, a sequel to Yoo and Lee (1990), attempts to investigate the interindustry determinants of technical efficiency in Korea's manufacturing industries, and also to conduct an exploratory analysis on the stability of technical efficiency over time. The hypotheses set forth in this paper are most found in the existing literature on technical efficiency. They are, however, revised and shed a new light upon, whenever possible, to accommodate any Korea-specific conditions. The set of regressors used in the cross-sectional analysis are chosen and the hypotheses are posed in such a way that our result can be made comparable to those of similar studies conducted for the U.S. and Japan by Caves and Barton (1990) and Uekusa and Torii (1987), respectively. It is interesting to observe a certain degree of similarity as well as differentiation between the cross-section evidence on Korea's manufacturing industries and that on the U.S. and Japanese industries. As for the similarities, we can find positive and significant effects on technical efficiency of relative size of production and the extent of specialization in production, and negative and significant effect of the variations in capital-labor ratio within industries. The curvature influence of concentration ratio on technical efficiency is also confirmed in the Korean case. There are differences, too. We cannot find any significant effects of capital vintage, R&D and foreign competition on technical efficiency, all of which were shown to be robust determinants of technical efficiency in the U.S. case. We note, however, that the variables measuring capital vintage effect, R&D and the degree of foreign competition in Korean markets are suspected to suffer from serious measurement errors incurred in data collection and/or conversion of industrial classification system into the KSIC (Korea Standard Industrial Classification) system. Thus, we are reluctant to accept the findings on the effects of these variables as definitive conclusions on Korea's industrial organization. Another finding that interests us is that the cross-industry evidence becomes consistently strong when we use the efficiency estimates based on gross output instead of value added, which provides us with an ex post empirical criterion to choose an output measure between the two in estimating the production frontier. We also conduct exploratory analyses on the stability of the estimates of technical efficiency in Korea's manufacturing industries. Though the method of testing stability employed in this paper is never a complete one, we cannot find strong evidence that our efficiency estimates are stable over time. The outcome is both surprising and disappointing. We can also show that the instability of technical efficiency over time is partly explained by the way we constructed our measures of technical efficiency. To the extent that our efficiency estimates depend on the shape of the empirical distribution of plants in the input-output space, any movements of the production frontier over time are not reflected in the estimates, and possibilities exist of associating a higher level of technical efficiency with a downward movement of the production frontier over time, and so on. Thus, we find that efficiency measures that take into account not only the distributional changes, but also the shifts of the production frontier over time, increase the extent of stability, and are more appropriate for use in a dynamic context. The remaining portion of the instability of technical efficiency over time is not explained satisfactorily in this paper, and future research should address this question.

• Journal of Energy Engineering
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• v.23 no.3
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• pp.42-50
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• 2014

Korean government has been investing more than 400 billion KRW in R&D on renewable energy. This paper aims to measure the R&D efficiency of national R&D program in the field of renewable energy, and to identify the sources of inefficiency. 4,213 R&D projects supported by Korean government during 2009-2011 are analyzed by using Data Envelopment Analysis and statistical tests. Results implies as follows. First, hydrogen, bio, fuel cell, photovoltaic have higher R&D efficiency than other renewable energies. Second, universities conducted national R&D program more efficiently than firms did, and small and medium sized enterprises are more efficient than large sized enterprises. Third, R&D inefficiency is mainly caused by the lacks of patent performance rather than excessive R&D investment or academic paper performance.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.5
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• pp.2093-2105
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• 2013

Successful implementations of domestic public construction projects have been increasingly concerned with the efforts to improve the inefficient execution. However, the existing factors causing the inefficient execution have been repeatedly occurred in many projects. This is because the previous studies have been concentrated on identifying the factors without in-depth analysis and systematic prioritization. This study has clarified the characteristics of the inefficient public construction projects, identified the causes, constructed their hierarchical structure, and analyzed the impacts on them. In particular, the critical factors causing the inefficient execution are prioritized by the outcomes derived from the questionnaire surveys, which is limited to the pre-construction stage. They are utilized in prioritizing the institutional and political improvements. However, in the future, the analytic and detailed guideline for remedying the factors causing the inefficient execution of a project should be studied, and their analysis will be extended to the construction stage.

• Journal of Korea Port Economic Association
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• v.28 no.2
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• pp.179-194
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• 2012

In this study, we compared the efficiency of container terminals using DEA. To do this, we designed an AHP/DEA hybrid model using AHP and DEA, and evaluated the efficiency by comparing the container terminal operation company in Gwangyang(KEC, KIT, GICT) and Busan(HBCT, DPCT, KBCT, UPT, Gamman, PNC, PNIT, HJNC, HPNT). The proposed model can control the number of selected promising container terminal by applying DEA-AR model. This model can also improve the credibility of analysis by using objective weights through the AHP application to efficiency evaluation data and normalizing the evaluation data to apply AHP and DEA. The model assumes inputs to be container crane, transfer crane, yard tractor, and reach stacker and output as container traffic. The result shows that DPCT was an efficient DMU.

• The KIPS Transactions:PartC
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• v.12C no.6 s.102
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• pp.891-900
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• 2005

This paper studies network recovery methods for WDM optical mesh networks, concentrating on improving spare resource utilization. The resource efficiency can be obtained by sharing spare resources needed for network recovery. To improve the sharability of spare resources in WDM networks, methods to share backup paths us well as spare capacity should be studied. The proposed method in this paper uses multiple ring-covers and this method provides fast and simple recovery operation by exploiting the characteristics of logical ring topology, and also provides efficient resource utilization by using multiple distributed backup paths to improve the sharability of overall spare resources in the networks. This method can provide layered reliability to network service by enabling hierarchical robustness against multiple failures. The performance results show that the proposed method provide improved resource efficiency for single failure and enhanced robustness for multiple failures.

• The Journal of the Korea Contents Association
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• v.10 no.12
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• pp.328-341
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• 2010

Korea Trucking Transport Business is one of principal national logistics sector, though, so many issues and problems came to arises, which brought cargo transport system crisis over the country such as logistics enormous jam and traffic. This paper analyzes the efficiency of korean trucking transport business firms using DEA model. We evaluate the CCR, BCC efficiency and RTS of 30 trucking transport firms. We also suggest the trucking transport firms which can be benchmarked based on analyzed information. The result shows that seven enterprises whose values of CCR efficiency are 1, and fifteen enterprises whose values of BCC efficiency are 1. RTS indicates IRS of 16 firms, DRS of 5 firms and CRS of 9 firms.