• 품질경영학회지
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• 제47권1호
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• pp.33-46
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• 2019

Purpose: This study proposed a DEA (Data Envelopment Analysis)-based stepwise benchmarking target selection for inefficient DMU (Decision Making Unit) to improve its efficiency gradually to reach most efficient frontier considering resource (DEA inputs and outputs) improvement preferences. Methods: The proposed method proceeded in two steps. First step evaluates efficiency of DMUs by using DEA, and an evaluated DMU selects benchmarking targets of HCU (Hypothesis Composit Unit) or RU (Real Unit) considering resource improvement preferences. Second step selects stepwise benchmarking targets of the inefficient DMU. To achieve this, this study developed a new DEA model, which can select a benchmarking target of an inefficient DMU in considering inputs or outputs improvement preference, and suggested an algorithm, which can select stepwise benchmarking targets of the inefficient DMU. Results: The proposed method was applied to 34 international ports for validation. In efficiency evaluation, five ports was evaluated as most efficient port, and the remaining 29 ports was evaluated as relative inefficient port. When port 34 was supposed as evaluated DMU, its can select its four stepwise benchmarking targets in assigning the preference weight to inputs (berth length, total area of pier, CFS, number of loading machine) as (0.82, 1.00, 0.41, 0.00). Conclusion: For the validation of the proposed method, it applied to the 34 major ports around the world and selected stepwise benchmarking targets for an inefficient port to improve its efficiency gradually. We can say that the proposed method enables for inefficient DMU to establish more effective and practical benchmarking strategy than the conventional DEA because it considers the resource (inputs or outputs) improvement preference in selecting benchmarking targets gradually.

• 한국전자거래학회지
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• 제18권4호
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• pp.327-338
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• 2013

IT프로젝트를 수행하는 기업은 정해진 예산범위 내에서 투자계획을 수립하고 실행하게 된다. 이 과정에서 IT프로젝트를 효과적, 효율적으로 선정하는 문제는 기업경쟁력과 직결되는 중요한 요소이다. 그동안 IT프로젝트의 선정을 위한 다양한 모형이 개발되었으나 예산제약을 고려한 효과적 프로젝트 선정에 대한 연구는 보고되지 않고 있다. 본 연구에서는 예산 제약을 고려하여 효과적으로 IT프로젝트를 선정하는 기법을 제시하였다. 본 연구에서 제안한 모델(AHP-K)에서는 AHP(Analytic Hierarchy Process : 계층분석법) 기법을 적용하여 평가 항목의 가중치와 프로젝트 후보군의 가중치를 산정한 후 배낭문제(Knapsack Problem)를 적용하여 예산 범위 내에서 프로젝트 효용을 최대화하는 선정안을 도출한다. 실제 적용단계에서 고려하는 대안이 많거나 신규대안이 추가되는 경우 쌍대비교의 수행이 어려운 점을 감안하여 대안 비교 단계에서 절대평가법을 적용하였다. 본 연구에서는 제시된 모델을 실제 사례에 적용하여 기존 AHP 모형과 비교 분석함으로써 효과성을 검증하였다.

• 한국컴퓨터정보학회논문지
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• 제12권4호
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• pp.169-177
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• 2007

본 연구에서는 기업의 비용 절감, 품질 향상, 수익성 및 유연성 향상 등에 직접적인 영향을 미치며, 이를 통하여 기업의 운영과 재정, 경쟁력 등에 영향을 미치는 전략적으로 매우 중요한 의사결정인 공급업체 선정을 위한 평가 모형 및 평가방법을 제시하고자 하였다. 이를 위하여 본 연구에서는 연구 대상 분야를 사무용품 및 사무기기 분야로 한정하여 사무용품 및 사무기기 공급업체 선정을 위한 평가요인을 1단계에서는 사무용품 및 사무기기 공급관련 요인, 제품관련 요인, 거래기업의 관리능력관련 요인으로 분류하고, 각 요인별로 세부요인을 설정하여 총 16개의 세부요인으로 분류하고, 각 요인별 상대적 중요도 산출을 위하여 설문조사를 실시하였다. 평가 요인별 상대적 중요도는 AHP기법을 이용하여 도출하였으며, 본 모형의 실제적인 활용 가능성을 제시하기 위하여 사무용품 및 사무기기 공급업체에 대한 평가 요인별 만족도를 도출하여 요인별 상대적 중요도를 이용한 공급업체에 대한 만족도를 도출하는 평가모형을 제시하였다.

• 생명과학회지
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• 제11권4호
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• pp.316-320
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• 2001

Sonication tremendously improves the efficiency of Agrobacterium infection by introducing small and uniform fissures and channels throughout the targeted tissue. Using shoot tips of cotton as explants, the effect of sonication treatment and virulence genes in Agrobacterium tumefaciens on transformation efficiency was investigated. The pat gene which encodes resistance to the herbicide, glufosinate, was used as a selectable marker. Transformation efficiency was evaluated on th basis of survival rates of cocultivated shoot tips on selection medium containing 2.5 mg/l gulfosinate-ammonium(ppt) adn 25. mg/l Clavamax. Sonication from 5 to 15 second has a positive effect on shoop tip survival. However, whil virE as well as virG or vir GN54D showed an enhancement in transformation efficiency, virE,. virG resulted in the most significant enhancement. Overall, the combination of additional virG/virE gene and sonication treatment resulted in the most significant increase in transformation efficiency.

• Journal of Electrical Engineering and Technology
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• 제10권2호
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• pp.586-594
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• 2015

This paper proposes a maximum efficiency operation strategy for three-level T-type inverter in entire operation areas. The three-level T-type inverter has higher and lower efficiency areas compared with two-level inverter. The proposed strategy aims to operate in the maximum efficiency point for the low-voltage and low-power home appliances. The three-level T-type inverter is analyzed in detail, and the two operation mode selection strategy is developed. The proposed algorithm is verified by theoretical analysis and experimental results.

• 전력전자학회논문지
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• 제25권2호
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• pp.127-132
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• 2020

In this study, single-phase and three-level boost converters applied to the photovoltaic system were compared and analyzed in terms of efficiency and power density according to the input voltage and load conditions. For accurate analysis of efficiency, the losses in each device of the single-phase and three-level boost converters were derived using mathematical equations and simulations by using the PSIM thermal module. Then, the losses were compared with the efficiency confirmed through the actual experiments. Results confirmed that the efficiency and power density can be improved by applying the three-level boost converter to the system according to the selection of the switching frequency.

• Membrane and Water Treatment
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• 제10권1호
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• pp.39-44
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• 2019

LID facilities do not consider environmental factors, and due to inappropriate vegetation planting causing degradation in efficiency due to plant damage and difficulty in maintenance. Therefore, in this study, assessment of impact environmental factor by seasonal variation of chlorophyll and growth of vegetation planted in LID technologies and change of pollutant reduction were conducted. In the case of B-SJ and B-RI, growth rate decreased after summer (August), and B-MG showed steady growth until autumn (September). Chlorophyll was found to increase during spring season while it decreased during autumn season. The chlorophyll concentration was found to affect the plant growth pattern. TN reduction efficiency was highest with greater than 80% efficiency in summer, and it was analyzed that plants were identified as the main factor affecting the seasonal reduction efficiency of TN. Also, temperature and relative humidity were analyzed to affect plant growth, activity and pollutant removal efficiency. Plant type and growth pattern are considered as factors to be considered in selection of appropriate plant types in LID technologies.

• 한국산업융합학회 논문집
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• 제27권2_2호
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• pp.325-332
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• 2024

Contemporary power systems demand efficient and sustainable technologies. Single-phase induction motors, while widely used, face efficiency challenges due to inherent rotor losses. Proposed solutions include the Line-start Permanent Magnet Synchronous Motor (LSPMSM), leveraging permanent magnets for enhanced energy density but facing demagnetization and cost issues. Alternatively, the Line-start Synchronous Reluctance Motor (LSRM) operates as a hybrid motor without permanent magnets, reducing rotor losses and potentially improving efficiency. This paper focuses on designing an LSRM rotor for air conditioner compressors, analyzing start-up characteristics and efficiency through finite element analysis. A comparative study with single-phase induction motors provides insights for future motor technology selection, balancing efficiency and other requirements.

• 로봇학회논문지
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• 제6권4호
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• pp.344-352
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• 2011

A mobile manipulator is a system with a robotic manipulator mounted on top of a mobile base. It has both indoor and outdoor applications for transporting or transferring materials. When a user gives commands, they are usually at high levels such as "move the object to the table," or "tidy the room." By intelligently decomposing these complex commands into several subtasks, the mobile manipulator can perform the tasks with a greater efficiency. One of the crucial subtasks for these commands is the pick-and-place task. For the mobile manipulator, selection of a good base position and orientation is essential to accomplishing this task. This paper presents an algorithm that determines one of the position and orientation of a mobile manipulator in order to complete the pick-and-place task without human intervention. Its effectiveness are shown for a mobile manipulator with 9 degrees-of-freedom in simulation.

• 경영과학
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• 제20권1호
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• pp.125-139
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• 2003

City gas is becoming an essential resource in households due to its convenience and low price in comparison to other energy sources. However, in order to prepare for the gas market to be saturated, many city gas companies must pursue customer satisfaction management and develop happy call systems for a promising solution. In the development of the happy call systems, the difficult problem is that we cannot contact all customers because of limited resources and calling efficiency in the call center, We should find best customers according to their value. This paper suggests a methodology for the selection of happy call customers when city 9as companies consider two strategies. First, they should launch a new business area. Second, they must attempt to prevent current customers from moving from city gas to other fuels. We will discover important attributes and derive rules of weighting for the attributes through an exploration study that affect customer satisfaction and preference. Through a simulation model, we will show how many customers will be selected by our methodology.