• 한국정밀공학회지
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• 제17권11호
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• pp.141-150
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• 2000

Continuously variable transmission(CVT) combined differential gear unit has many advantages, which are the decrease of CVT size, the increase of overall efficiency, the extension of speed ratio range, and the generation of geared neutral. It is known that such CVT can be classified into the input coupled type and the output coupled type according to the coupling location of continuously variable unit(CVU). In this paper, six different configurations of input coupled type CVT combined V-belt CVU and 2K-H I type differential gear unit are proposed. Some useful theoretical formula related to speed ratio, power flow and efficiency are derived and analyzed. The propriety of derived formula and theoretical analysis are proven by various experiments.

• 한국항해항만학회지
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• 제42권6호
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• pp.501-506
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• 2018

컨테이너터미널은 적정 규모의 선석(길이)과 야드 부지를 확보하였을 때, 운영 효율성이 극대화 될 수 있다. 하지만 부산신항을 비롯한 일부 컨테이너항만은 운영주체 분리로 인해 다수의 터미널이 분리 운영되어 물류 효율성에 제약이 존재한다. 이 연구에서는 인접한 2개의 컨테이너터미널에 야드 코피티션 영역을 활용할 경우, 기존에 비해 전체 터미널 운영(물류) 효율성이 크게 제고될 수 있음을 분석한다.

• KDI Journal of Economic Policy
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• 제42권4호
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• pp.91-116
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• 2020

As a project appraisal tool, the preliminary feasibility study (PFS) has contributed to enhancing the efficiency of public investment decision-making in the Republic of Korea over the last two decades. To overcome the limitations of the efficiency-oriented cost-benefit analysis, the PFS accommodates equity concerns among regions, namely balanced regional development (BRD) analysis. This study attempts to gauge the contributions of BRD analysis to PFS results. Specifically, it addresses how effectively policy efforts to promote decision-making have been implemented in the PFS stage while also considering the balance between equity and efficiency in terms of the trade-off between them, the degree to which they influence the results, and whether the consideration of equity is in fact actually reflected in seriously underdeveloped regions as intended. The study finds that the PFS results over the last two decades have been largely in line with the background and policy objectives. Based on the findings of the study, needs for institutional improvement are suggested, including enhancements in the analysis of regional economic ripple effects and taking into account the psychological factors pertaining to the evaluators in the overall judgment.

• 재무관리연구
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• 제20권2호
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• pp.263-291
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• 2003

이 연구는 Generalized Malmquist 지수를 이용하여 1997년 외환위기 때부터 2001년까지 국내 생명보험산업의 생산성변화를 기술효율성, 규모효율성 및 기술진보의 변화로 구분하여 측정하였다. 생명보험 산업의 생산성은 외환위기에도 불구하고 매년 증가하였음을 확인하였으며, 기술진보와 규모효율성의 변화는 순수기술효율성의 하락을 상쇄하고 생산성향상에 기여하였으며, 특히 기술변화가 더 크게 생산성향상에 공헌하였음을 확인하였다. 이러한 생산성의 증가는 구조조정으로 기인한 것으로 보인다. 외환위기 이후에 효율성은 계속하여 하락하였으며, 이것은 선도 생명보험회사의 효율적 프론티어가 일반 생명보험화사의 생산성보다 더 크게 증가하였기 때문에 발생한 것으로 확인되었다. 낮은 효율성은 생산성의 증가에도 불구하고 경영개선에 의하여 생산성을 크게 증가시킬 수 있다는 것을 말해주고 있다.

• 품질경영학회지
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• 제36권4호
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• pp.102-116
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• 2008

The most widely used models to study the quality of service are the SERVQUAL and SERVPERF models that measure service mechanisms. This paper is to estimate service efficiency and consistency for Retail Industry. We tried to measure the service quality and overall satisfaction by using DEA and PCI, degree of combination and top2box which is a little bit different methodology from traditional ones. Rather than using the usual method of converting the service quality index by mean value, the Service Efficiency Index(SEI) and Service Quality Consistency Index(SQCI) are used to measure the efficiency and consistency level, which in turn can be used as the new service quality indices. The result of SEI and SQCI show the efficiency frontier in retail industry that 6 DMUs are analyzed relative efficient DMUs, 12DMUs are inefficient DMUs and retail Industry consistency level appeared low(0.35-0.47) Also, there is a significant difference in terms of efficiency and consistency in the each retail industry. Finally, we showed the summarized result as the Effi-Con Matrix.

• JSTS:Journal of Semiconductor Technology and Science
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• 제3권1호
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• pp.47-54
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• 2003

New efficiency enhancement techniques have been devised and implemented to InGaP/GaAs HBT MMIC power amplifiers for W-CDMA mobile terminals applications. Two different types of bias current control circuits that select the efficient quiescent currents in accordance with the required output power levels are proposed for overall power efficiency improvement. A dual chain power amplifier with single matching network composed of two different parallel-connected power amplifier is also introduced. With these efficiency enhancement techniques, the implemented MMIC power amplifiers presents power added efficiency (PAE) more than 14.8 % and adjacent channel leakage ratio(ACLR) lower than -39 dBc at 20 dBm output power and PAE more than 39.4% and ACLR lower than -33 dBc at 28 dBm output power. The average power usage efficiency of the power amplifier is improved by a factor of more than 1.415 with the bias current control circuits and even up to a factor of 3 with the dual chain power amplifier.

• 한국유기농업학회지
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• 제22권1호
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• pp.1-23
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• 2014

The purpose of this paper was to measure technical efficiencies and scale efficiencies of Korean seed industry by DEA method, and to identify the factors affecting the efficiencies by Tobit regression model. Survey data of 50 seed companies nationwide were applied for the analysis. The average score of overall technical efficiency for the surveyed companies in 2012 was 0.44, which is decomposed into pure technical efficiency 0.68 and scale efficiency 0.63. A majority of the seed companies exhibited at least one form of inefficiency except a few companies in optimal scale. It was also shown the most companies were operating in the stage of increasing returns to scale, which implies Korean seed companies are mainly in smaller scale than optimal. Additional results suggest that the Center for Private Seed Companies, which will be established at Gimje in 2015, plays an important role to make domestic seed companies improve their scale efficiency as well as pure technical efficiency by way of enlarging their size and co-using the high technology in the Center.

• Journal of Power Electronics
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• 제16권2호
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• pp.666-674
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• 2016

In this paper, a high efficiency satellite electrical power supply system is proposed. The increased efficiency of the power supply system allows for downscaling of the solar array and battery weight, which are among the most important satellite design considerations. The satellite power supply system comprises two units, namely a generation unit and a storage unit. To increase the efficiency of the solar array, a maximum power point tracker (MPPT) is used in the power generation unit. In order to improve the MPPT performance, a novel algorithm is proposed on the basis of the hill climbing method. This method can track the main peak of the array power curve in satellites with long duration missions under unpredicted circumstances such as a part of the array being damaged or the presence of a shadow. A lithium-ion battery is utilized in the storage unit. An algorithm for calculating the optimal rate of battery charging is proposed where the battery is charged with the maximum possible efficiency considering the situation of the satellite. The proposed system is designed and manufactured. In addition, it is compared to the conventional power supply systems in similar satellites. Results show a 12% increase in the overall efficiency of the power supply system when compared to the conventional method.

• 보건행정학회지
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• 제9권4호
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• pp.87-119
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• 1999

The main purpose of this research is to measure and analyze how productive the health centers are and how much inputs(or outputs) in the inefficient health centers should be decreased(or increased) for efficiency. The evaluation of the performance of health centers gives a strong incentive to improve resource allocation in regional health planning. It has been, however, implemented very rarely until now. In this regard, this paper measures the performance of the health centers with a single indicator for multiple-outputs in terms of productivity(technical efficiency), based on Data Envelopment method. The 20 Kyungnam health centers which provide clinic services and specific primary health care services were analyzed. The results show that 50.0% of 20 health centers were productive with respective to overall technical efficiency, 65.0% were productive for pure technical efficiency, and 50.0% for scale efficiency. The inefficient group includes Geoje, Mahsan, Miryang, Sahchun, Tongyoung, Gosung, Nahmhae, Euryang, Hahmahn, Hahbchun health centers. The worst case was identified as Tongyoung health center which represented a 47.5% efficiency, compared with productive health centers. The empirical results for input-output analysis indicates that the low-productive health centers have excessive manpower in administration department, producing low outputs in clinical services and vaccination program. These findings imply that a systemic evaluation of the performance of the Korean health centers and the subsequent structural reform are strongly required.

• 경영과학
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• 제30권2호
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• pp.43-61
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• 2013

With the recent introduction of supply chain management (SCM), quality management has extended from within companies to between companies. As a result, supply chain quality management (SCQM) has received increased attention. However, existing SCQM studies only focus on what impact quality control in supply chains have on company performance while virtually no studies examine quality control efficiencies. This paper, therefore, evaluated the SCQM efficiency of a parent company and its partner companies by using Data Envelopment Analysis (DEA) based on the Quality Collaboration Index for Supply Chain Management (QCI-SCM) conducted by the Korean Standards Association for its 'Quality Innovation-Based Building and Expansion of Business.' Study results showed that a parent company and its partners showed an overall average efficiency of approximately 80% (parent company 80.37%, partner company 79.05%). By also performing a discriminant analysis based on the calculated efficiency scores using DEA, factors that made companies efficient or inefficient were different between the two groups. In parent companies, efficiency and inefficiency were determined by factors such as communication, infra-structure, support, delivery of quality, and benefit sharing, whereas in partner companies, talent development, infrastructure, crisis management, and delivery of quality were the determining factors. In this paper, we examined the efficiency of SCQM and analyzed them from the perspective of both the parent company and partner companies to offer strategic SCQM insights.