• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 B
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• pp.1049-1050
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• 2006

This paper is proposed to a novel DC-DC converter operated high efficiency for loss-less snubber capacitor. The general converters of high efficiency is made that the power loss of the used switching devices is minimized. To achieve the soft switching operation of the used control switches, the proposed converter is constructed by using a loss-less snubber capacitor. The proposed converter achieves the soft-switching for all switching devices without increasing their voltage and current stresses. The result is that the switching loss is very low and the efficiency of converter is high. The soft switching operation of the proposed converter is verified by digital simulation and experimental results.

• 한국항해항만학회지
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• 제30권4호
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• pp.267-275
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• 2006

Due to the growth of container traffic and port competition, ports have increasingly been under pressure to improve their efficiency in port operation and port management for competitive edge. The purpose of this study is to compare the technical efficiency among major container terminals in China, Korea and Singapore using Data Envelopment Analysis (DEA). This paper analyses the returns-to-scale using the output orientation of VRS and CRS model. The benefits of this study examining the relative performance of container terminals will enable container terminal operating companies or port policy makers in those countries to identify current slacks and to set up a proper port management and operation plan to improve their productivity.

• 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.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 추계학술대회 논문집
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• pp.171-174
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• 1997

The great development of semiconductor industry demands the high efficiency and performance of related device, but the pick and place system of semiconductor packaging device can load a few units until nowdays. Although the system can load a lot of units, it can work multiple sort operation. The defect like that causes a low efficiency. Therefore, this paper represents the development of pick and place system which can work multiple sort operation.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2005년도 전력전자학술대회 논문집
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• pp.266-268
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• 2005

A new synchronous switch controlled transient current build-up zero voltage switching (TCB-ZVS) forward converter is proposed. The proposed converter is suitable for the low-voltage and high-current applications. The features of the proposed converter are low conduction loss of magnetizing current, no additional circuit for the ZVS operation, high efficiency, high power density and low EMI noise throughout all load conditions.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 하계종합학술대회 논문집(5)
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• pp.249-252
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• 2001

A large number of soft switching topologies included a resonant circuit have been proposed. But these circuits increase number of switch in circuit and complicate sequence of switching operation. In this Paper, the authors propose power conversion system, DC-AC inverter of high efficiency and high power factor with soft switching mode by partial resonant method. The result is that the switching loss is very low and the efficiency of system is high. And the snubber condenser used in partial resonant circuit makes charging energy regenerated at input power source for resonant operation.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1992년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 19-21 Oct. 1992
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• pp.811-816
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• 1992

The objective of cell operation in CIM is to maximize system efficiency, not the cell itself. We introduce a cell operation scheme that pursues the direction. For specific cases, work center and AS/RS are closely investigated. Structures of their operation mechanism and methods of job scheduling are introduced along with an expert system developed for the scheme. The cell operation softwares developed are now under test at K.U.FMS, a model CIM plant.

• 교육녹색환경연구
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• 제9권1호
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• pp.41-51
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• 2010

It is high level of management activity for the fixed property of building to operating spaces for education in university campus. Therefore, this study is focused on definition of the factors for analyzing the actual conditions of space operation and application of them to C university campus in Gyeongbuk in the aspect of infrastructure of university and efficiency of space operation. These analytical factors are the rate of lecture and experimentation room, the rate of theoretical and experimental subject in curriculum and unit area for infrastructure and the rate of use, turnover rate and occupation rate per lecture for space operation. If the analytical factors of space operation are systemized as program module for space operation, the space management system of university campus will be characterized on the foundation of university information system. And it will be able to support the decision making about space management. It needs to integrate various type of information and data of university to increase the efficiency of decision making.

• 한국유체기계학회 논문집
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• 제18권2호
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• pp.67-72
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• 2015

The purpose of this study is to achieve energy saving effect of inverter driving multistage centrifugal pump. For determining the operation points in the pump system, the system curves should be obtained experimentally. To get the system curves, three pumps combined in parallel and one pump operated with different rotational speeds. But for variable speed pump system, energy saving rates can not be evaluated from operation efficiencies. That is why operation efficiencies, system curves, duty cycles, and input powers of the pump system were measured by the constructed experimental apparatus. The duty cycle segmented into different flow rates and weighting the average value for each segment by the interval time. The system was operated with two different periods. The mean duty cycles were collected from apartment and found that the system operated at 40% and at 50% or below capacity. Measured energy saving rate was 58.16%. Estimating method of energy saving rate could be more effective operation index than that of operation efficiency.

• 풍력에너지저널
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• 제14권3호
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• pp.61-68
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• 2023

This paper aims to perform optimal operation and maintenance with an integrated monitoring system for offshore wind platforms. Based on the wind direction and wind speed data of existing wind farms, a monitoring system was established along with weather and weather data to maximize the operational efficiency of wind farms. Compared to wind power on land, offshore wind power is difficult to maintain due to weather, logistics and geographical limitations. Therefore, economic analysis of actual operation and maintenance is essential for large-scale offshore wind farms. In this paper, the availability of offshore wind farms was analyzed by using personnel resources, parts inventory, Crew Transfer Vessel (CTV) and Specialized service Operation Vessel (SOV) etc. before the actual operation and maintenance of wind farms. A comparative analysis was conducted to determine the optimum operating efficiency and economical maintenance costs.