• 한국콘텐츠학회논문지
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• 제17권1호
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• pp.201-212
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• 2017

본 연구에서는 변동계수를 이용하여 DEA 모형의 변별력 평가에 적용할 수 있는 새로운 평가기준을 제시하였다. 변별력 평가를 위해 기존 연구에서 제시한 중요도와 본 연구에서 제안한 변동계수를 이용하여 변별력을 분석하였다. 다양한 DEA 모형들 중 변별력 평가를 위해 CCR-DEA, BCC-DEA, entropy, bootstrap, super efficiency, cross efficiency DEA 모형을 선정하고 실증분석을 실시하였다. 모형들의 순위상관관계를 파악하기 위해서 CCR 모형과 BCC 모형의 효율성 값과 entropy, bootstrap, super efficiency, cross efficiency 모형의 효율성 값들 간에 순위상관분석을 실시하였다. 본 연구를 통해 도출된 연구결과를 요약하면 다음과 같다. 첫째, 중요도와 변동계수를 이용한 모형들의 변별력 순위가 동일한 것으로 분석되어 변동계수를 DEA 모형의 변별력 평가기준으로 이용할 수 있다는 것이다. 둘째, 본 연구의 실증분석 결과에 따르면 4개 모형 중 super efficiency 모형이 변별력이 가장 높은 것으로 분석되었다. 셋째, CCR 모형과 순위상관관계가 가장 높은 모형은 super efficiency 모형으로 나타났고, BCC 모형과 순위상관관계가 가장 높은 모형도 super efficiency 모형으로 분석되었다.

• 품질경영학회지
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• 제43권4호
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• pp.533-544
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• 2015

Purpose: The purpose of this study is to analyze the cost efficiency of food industry in JeollaNamdo. And this study is focused on the correlation between the economic efficiency of food industry and its cost efficiency, based on the analysis of 372 food companies' data in JeollaNamdo in 2012. Methods: DEA cost minimization is the measurement of the cost efficiency of JeollaNamdo food industry in 2012. In this study, the CCR and BBC models have been employed to analyze the decomposing cost efficiency-technical efficiency, allocative efficiency, and scale efficiency respectively. And the Spearman rank correlation and Wilcoxon signed rank test also have been employed to check the correlation and difference between the ranking orders based on the efficiency scores respectively. Results: For the CCR model, mean cost efficiency was found to be 0.084(0.54 for allocative efficiency and 0.19 for technical efficiency). For the BCC model, mean cost efficiency was found to be 0.252(0.453 for allocative efficiency and 0.564 for technical efficiency). Average scale efficiency was found to be 0.38. In analyzing the results, this study argues that the optimal way to improve cost efficiency is by reducing inputs proportionally and changing their combination. Conclusion: The efficiency scores of the two models show high correlation, whereas, the differences between them are also found to be significant. Hence, it should be cautious to select a suitable model when we do the research.

• 수산해양교육연구
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• 제22권1호
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• pp.67-78
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• 2010

The purposes of this study are to analysis correlations of teachers' developments, organizational conflicts, and school organizational efficiency, and to test the influences of teachers' developments and organizational conflicts on school organizational efficiency. The data were collected from 240 elementary school teachers in Busan. Pearson's correlation analysis among sub-factors and stepwised multiple regression analysis were applied. The research findings are as follows: First, most of the sub-factors of teachers' developments, organizational conflict, and organizational efficiency had statistically significant correlations, showing positive correlation between sub-factors of teachers' developments and organizational efficiency and negative correlation between sub-factors of organizational conflicts and organizational efficiency. Second, through stepwised multiple regression analysis at the significance level of 5%, 'conflicts against administrator' was the most significant predictor with 31.4% explanation of the variance of organizational efficiency. These results suggest the necessity of training to promote teachers' developments and administrators' leadership.

• 한국정보통신학회논문지
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• 제18권10호
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• pp.2433-2442
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• 2014

본 논문에서는 전자사진 기술을 이용하는 프린터, 복사기, 팩시밀리, 복합기 등과 같은 이미징 장치의 효율등급기준에 대한 연구를 수행하였다. 대기전력을 관리하고 있는 현 제도의 문제점을 파악하고 효율관리 필요성을 제안하였으며, 이를 위한 효율 기준을 국내 대기전력저감 프로그램에 등록된 실증 데이터를 기반으로 개발하였다. 효율부여지표를 찾기 위해 상관분석(Correlation Analysis)을 실시하였으며, 인쇄 속도가 가장 큰 상관계수(Correlation Coefficient)를 가짐을 확인하였다. 이를 적용한 복합기, 프린터에 대한 1~5 등급의 효율등급 기준과 에너지 프론티어 기준을 도출하였으며, 정책반영 시 연간 약 650 억 원의 에너지 비용을 절감할 것으로 기대한다.

• 한국유체기계학회 논문집
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• 제20권2호
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• pp.17-25
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• 2017

Prediction of performance and operating characteristics of a state-of-the-art ultra-supercritical (USC) steam turbine is an important issue in many ways. Theoretical and empirical correlation equations, developed a few decades ago, have been widely used in commercial programs for a prediction of performance. To improve of these correlation equations and apply them to the high pressure turbine of a USC steam turbine, computational fluid dynamic analysis was carried out and correlation equations to calculate efficiency variation of each stage were made. Both fluid dynamic characteristic and thermodynamic performance was analyzed for the development of the correlation equations. In particular, the impact of flow addition through an overload valve (OLV) between stages was examined throughly. The trend of pressure drop due to the flow mixing by the OLV flow addition was analyzed and an efficiency correlation equation considering the OLV flow was also made.

• Nuclear Engineering and Technology
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• 제45권2호
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• pp.203-210
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• 2013

The objective of this conducted research is to study the iodine removal efficiency in a self-priming venturi scrubber for submerged and non-submerged operating conditions experimentally and theoretically. The alkaline solution is used as an absorbent, which is prepared by dissolving sodium hydroxide (NaOH) and sodium thiosulphate ($Na2S_2O_3$) in water to remove the gaseous iodine ($I_2$) from the gas. Iodine removal efficiency is examined at various gas flow rates and inlet concentrations of iodine for submerged and non-submerged operating conditions. In the non-submerged venturi scrubber, only the droplets take part in iodine removal efficiency. However, in a submerged venturi scrubber condition, the iodine gas is absorbed from gas to droplets inside the venturi scrubber and from bubbles to surrounding liquid at the outlet of a venturi scrubber. Experimentally, it is observed that the iodine removal efficiency is greater in the submerged venturi scrubber as compare to a non-submerged venturi scrubber condition. The highest iodine removal efficiency of $0.99{\pm}0.001$ has been achieved in a submerged self-priming venturi scrubber condition. A mathematical correlation is used to predict the theoretical iodine removal efficiency in submerged and non-submerged conditions, and it is compared against the experimental results. The Wilkinson et al. correlation is used to predict the bubble diameter theoretically whereas the Nukiyama and Tanasawa correlation is used for droplet diameter. The mass transfer coefficient for the gas phase is calculated from the Steinberger and Treybal correlation. The calculated results for a submerged venturi scrubber agree well with experimental results but underpredicts in the case of the non-submerged venturi scrubber.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2003년도 추계학술발표회
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• pp.565-569
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• 2003

One-year-long groundwater-level data have been collected from 18 wells in Cheon-an area. The result of barometric efficiency, autocorrelation, cross-correlation and statistical distribution evaluated from the measurement data shows that groundwater-level measurements from observation wells are the principal source of information about aquifer characteristics. Data from WA-2 has high barometric efficiency as well as steady decreasing auto-correlation coefficient, which means nonleaky confined aquifer, Most aquifers in this study show the unconfined properties so that barometric efficiencies are mostly low and the coefficients of cross-correlation between groundwater-level and precipitation are commonly high. This study showed that the long-term groundwater-level monitoring data without artificial stress such as pumping would give accurate information about aquifer characteristics.

• 한국IT서비스학회지
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• 제12권4호
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• pp.255-265
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• 2013

This paper proposes a DEA-AR model for the efficiency evaluation of the iron ore brands in an integrated steel mill. The input factor is defined as unit cost of each brand based on CIF and two output factors are chosen as Fe and Al which are the important ingredients of iron ore. The relative importance between two output factors is determined by several experts using AHP model. The efficiency of each brand is determined using DEA and DEA-AR models. The negative correlation between the DEA-AR efficiency and the unit cost (CIF) is shown as significant whereas no significant correlation exist between the efficiency and the output factors. Also, the Kruskal Wallis rank sum test shows that there exist efficiency differences among the iron ore types whereas no difference is shown among the countries. The result could be utilized in selecting good brands of iron ores based on the DEA-AR efficiency in an integrated steel mill.

• 산업경영시스템학회지
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• 제37권3호
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• pp.82-88
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• 2014

The government expands its investment on R&D programs for economic growth, thus there is growing attention on the result of R&D Programs. This study proposes more improved measuring method for efficiency when the number of R&D programs is not enough to be for measuring efficiency analysis. It provides more various application method of factors on efficiency analysis. This study analyzes the influence of each input factor on efficiency by using partial efficiency concept. And it also determines input factors in similar influence throughout Spearman correlation coefficient. Finally, it suggests new method to improve discriminatory power of efficiency analysis by determining representative factors. Also, the proposed method can be practiced not only for national R&D programs, but also for other fields of research.

• 산업공학
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• 제24권4호
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• pp.314-322
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• 2011

This study analyzes a relationship between Data Envelopment Analysis(DEA) efficiency scores and a normalization index in order to examine the validity of DEA models. A normalization index concerned in this study is 'sales per R&D project fund' which is regarded as a crucial R&D project performance evaluation index in practice. For this correlation analysis, three distinct DEA models are selected such as DEA basic model, DEA/AR-I revised model(i.e. DEA basic model with Acceptance Region Type I constraints) and Super-Efficiency(SE) model. Especially, SE model is adopted where efficient R&D projects(i.e. Decision Making Units, DMU's) with DEA efficiency score of unity from DEA basic model can be further differentiated in ranks. Considering the non-normality and outliers, two rank correlation coefficients such as Spearman's ${\rho}_s$ and Kendall's ${\tau}_B$ are investigated in addition to Pearson's ${\gamma}$. With an up-to-date empirical massive dataset of n = 482 R&D projects associated with R&D Loan Program of Korea Information Communication Promotion Fund in the year of 2011, statistically significant (+) correlations are verified between the normalization index and every model's DEA efficiency scores with all three correlation coefficients. Especially, the congruence verified in this empirical analysis can be a useful reference for enhancing the practitioner's acceptability onto DEA efficiency scores as a real-world R&D project performance evaluation index.