• 한국태양에너지학회 논문집
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• 제21권1호
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• pp.11-20
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• 2001

In this paper described common MPPT(Maximum Power Point Tracking) control algorithm; Constant Voltage Control, P&O(Perturbation and Observation), IncCond(Incremental Conductance), and investigated it's efficiency. Through simulation and efficiency evaluation, analyze the steady/transient states characteristics and efficiency of control algorithms respectively. Also, To high-efficiency proposed Two-mode MPPT control for improve on the existing control algorithm. Moreover, this paper suggested a topology for MPPT measuring efficiency and a method of examination.

• International Journal of Railway
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• 제1권2호
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• pp.37-44
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• 2008

Safe, fast, efficient and effective railway is a main factor of economic development level of every country. This paper uses the DEA method to evaluate and compare the efficiency of 12 Regions of RAI. In addition, we introduce the reference(s) unit(s) for every inefficient region, and determine the amount of input decrease and/or output increase need to become them efficient. Findings indicate that in 2006, 4 regions of 12 are in Constant Return to Scale (CRS) status and 7 of them in Variable Return to Scale (VRS), and the average efficiency is 0.730 and 0.888, respectively. In other words, RAI works 27 percent under its capacity. More over results indicate that Hormozgan, Khorasan, Tehran and Isfahan Regions have the most efficiency respectively. The results show that the 8 regions, have been working in Increaser Return to Scale and 4 reminder Regions in Decrease Return to Scale. According to this results, we submit the suitable suggestion for improve the efficiency of the inefficient regions.

• 한국전자거래학회지
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• 제9권2호
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• pp.33-50
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• 2004

본 논문에서는 정보화 투자에 대한 성과평가를 통해 공공부문의 정보화 예산투자에 대한 타당성과 효과성 측정 방안, 그리고 투자대비 효과의 적합성을 제고 할 수 있는 계량적 평가모델을 제시하였다. 즉, 전자정부 과제로 추진된 정부전자문서유통센터 구축사업을 대상으로 정보화 투자에 대한 명확한 성과목표를 설정하고 사전평가 및 사후평가를 객관적으로 측정할 수 있는 핵심성과지표(KPI)를 개발하여 계량적 평가모델을 이용한 현장검증 연구방식으로 성과평가 결과를 도출하였다.

• 디지털융복합연구
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• 제11권8호
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• pp.31-39
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• 2013

최근 소셜미디어, 산업 간 융합 등이 확대되고, 기존의 PC뿐만 아니라 스마트폰, 태블릿 PC 등 다양한 스마트 기기를 통한 인터넷 이용이 증가하면서 수많은 비정형 데이터를 발생됨에 따라 빅 데이터 시스템에 대한 관심이 증가하고 있다. 시장조사 전문기관에서는 향후 5년에는 현재보다 데이터량이 9배가 증가할 것으로 전망하고 있으며, 빅 데이터 시장도 더 커질 것으로 예상하고 있다. 본 논문에서는 빅 데이터가 갖추어야할 효율성 품질평가 항목을 요구사항 분석을 통해서 도출하고 평가항목을 세분화하여 빅 데이터에 대한 효율성 시험 평가를 하였다.

• 대한가정학회지
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• 제42권6호
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• pp.137-149
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• 2004

This research analyzed the tasks performed by firm's consumer department, evaluation, and efficiency of those tasks. In addition, regression analysis was employed to find what factors influence the level of evaluation and efficiency of tasks performed by firm's consumer department. Research results summarized as follows. First, two thirds of the appropriate amount of resources and systems for the consumer department were equipped and the score of evaluating for consumer counseling tasks was high. Second, the amounts of resources and systems being equipped by the firm's consumer department were greater in insurance companies and firms with more employees, firms with 70% to 100% female employees in the consumer department, firms that listed their stocks, and firms with the consumer department located higher than the second floor. Third, the score of evaluating the tasks performed by the firm's consumer department was greater in firms that listed their stocks, owned great resources and systems, and had a higher degree of work satisfaction. Finally, the task of consumer counseling performed by the consumer department turned out to be effective in firms that listed their stocks, were recently established, and owned necessary resources and systems.

• 경영과학
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• 제29권1호
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• pp.33-56
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• 2012

Domestic LCD TV market is composed of two groups of products produced by major firms and small and medium enterprises. The major companies make the price relatively high, but the other makes lower in the same sizes. The model of the low price products does not make consumers choice when they choose LCD TV. This makes the questions of capability between difference price products. The reason above mentioned, the firms that include group of comparatively lower price, are worried about not increasing sale because of prejudice. This study is to find any interrelationship and evaluate the efficiency between the products using performance, exterior and brand power of product. In order to do this, a hybrid AHP/DEA evaluation model for comparison/valuation of LCD TV products is developed. The proposed process is; first, to derive hierarchy structure of LCD TV evaluation criteria using axiomatic design, second, to calculate the score of each LCD TV product through AHP analysis including weight calculation of evaluation criteria, and last, to evaluate the efficiency of LCD TV product by applying DEA by defining product scores as output and prices as input. It concludes that the high price products shows good efficiency, but there are some products with good exterior and brand power, not performance, also presenting good efficiency.

• 대한인간공학회지
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• 제29권4호
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• pp.647-654
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• 2010

In a service environment, the spatial layout is an important factor that has a great impact on customers' behavioral characteristics including wayfinding and purchasing. Previous studies have shown a gap between marketing, focusing solely on profitability and satisfaction, and architecture, looking only into efficiency of pedestrian flow. To balance such disparity, this study suggests an integrated approach for assessing behavioral patterns in complex service environments. With the objective that complex service environments should aim to increase its profitability and efficiency while guaranteeing customer satisfaction, quantitative metrics was developed for evaluation. The metrics was defined to use data from behavior observation including path tracking, population counting, and gaze analysis, while previous studies have relied on abstract survey methods that were prone to sampling errors and loss of data. For validation of the metrics in a real world setting, a case study was conducted at 4 train stations in Korea. In the case study, experiments were conducted to gather the required data in all 4 train stations, while their physical layouts were also analyzed. With the results from the case study, comparative evaluation of the 4 train stations in terms of behavioral efficiency was possible, together with a discussion on the effect of their physical settings.

• 한국자동차공학회논문집
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• 제23권6호
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• pp.591-600
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• 2015

The efficiency of a powertrain system of hybrid vehicle is highly dependent on the design and control of the hybrid powertrain system. In other words, the optimal design of the powertrain systems is coupled with optimal control of the powertrain system. Therefore, the solution of an optimal design problem for hybrid vehicles is computationally and timely very expensive. For example, dynamic programming, which is a recursive optimization method, is usually used to evaluate the best fuel economy of certain hybrid vehicle design, and, thus, the evaluation takes tens of minutes to several hours. This research aims to accelerate the speed of efficiency evaluation of hybrid vehicles. We suggest a mathematical treat and a methodological treat to reduce the computational load. The mathematical treat is that the dynamics of system is discretized with sparse sampling time without loss of energy balance. The methodological treat is that the efficiency of the hybrid vehicle is inferred by characteristic loss evaluation that is computationally inexpensive. With the suggested methodology, evaluating a design candidate of hybrid powertrain system is taken few minutes, which was taken several hours when dynamic programming is used.

• 한국산학기술학회논문지
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• 제22권5호
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• pp.517-529
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• 2021

본 연구의 목적은 전국 대학 유아교육과의 효율성 변화를 분석하여 교원양성기관 역량진단의 효과성을 살펴보고, 효율적인 유아교육과와 비효율적인 유아교육과의 특성 및 효율성에 영향을 끼치는 변수들을 확인하여 정책적인 시사점을 제공하는 데에 있다. 연구목적을 위해 전국 대학 유아교육과 149개 데이터를 사용하여 자료포락분석을 실시, 교원양성기관 평가 완료 이전의 효율성 연구결과와 비교분석하였다. 불변규모수익기술과 가변규모수익기술을 가정한 산출지향 모형을 추정하여 CCR과 BCC모형으로 상대적 운영효율성 추정하였고, 투입요소로는 전임교원 1인당 학생 수, 학생 1인당 장학금, 전임교원 1인당 연구비, 학생 1인당 장서 수, 학생 1인당 교육비를 산출요소로는 전임교원 1인당 연구실적, 취업률을 사용하였다. 토빗모형을 통해 투입, 산출요소 및 외생변수(설립유형, 학교종류, 입학정원규모, 소재지) 중 효율성에 영향을 끼치는 요인들을 살펴보았다. 연구결과, 전국 대학 유아교육과는 효율적으로 운영되고 있으며 3주기 및 4주기 교원양성기관 평가 완료 전과 규모효율성과 운영효율성에 차이가 없었다. CCR에서 강효율 유아교육과는 학생 1인당 장학금, 장서 수, 교육비가 유의하게 낮음에도 불구, 유의하게 높은 전임교수 1인당 연구실적과 취업률을 보이나, BCC 아래 학생1인당 장서 수, 취업률 이외에는 통계적 유의성을 상실하며, 토빗모형 계수도 실제적인 영향을 논하기에는 미미하다. 전문대학과 입학정원규모 60명 이상, 광역권 유아교육과의 운영효율성이 높은 것으로 확인되었다. 본 연구결과는 교육의 질적 향상을 통한 효율성 증대를 목적으로 하는 평가정책에 시사점을 준다.

• 대한안전경영과학회:학술대회논문집
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• 대한안전경영과학회 2008년도 춘계학술대회
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• pp.339-344
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• 2008

This study's purpose centers plant management activities that is management system for total plant efficiency's maximization, plant evaluation system that production and safety management activities factor that is enforcing in manufacturing industry can develop evaluation model that can evaluate quantitative activities in process that maximize productivity and safety efficiency wishes to do design.