• Journal of Electrical Engineering and Technology
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• 제1권1호
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• pp.16-22
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• 2006

Selective ground relays (SGRs) are useful fur distinguishing a faulted feeder from the sound feeders in ungrounded systems. However, they sometimes mis-operate due to human or device errors. Particularly, the reversed polarity of zero-sequence current transducers (ZCTs) is the most frequent cause of mis-operation. This paper presents a modified SGR for reducing the probability of mis-operations caused by the reversed polarity of ZCTs. The modification is achieved by introducing an adaptive time delay, which depends on the magnitude of the zero-sequence current and the phase angle deviation from the reference. The modified SGR was successfully demonstrated on a sample ungrounded system without mis-operation.

• 한국정보시스템학회지:정보시스템연구
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• 제3권
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• pp.133-145
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• 1994

Performance evaluation is essential for the successful management and operation of MIS. The more MIS grows and relevant investment enlarges, the more performance evaluation grows in importance. However, MIS managers as well as top management still have difficulty in evaluating the performance of MIS. This arises from various reasons, such as the specialty of MIS, diversified influences of MIS, multidimensionality of evaluation items, and the difference between evaluation levels. In this paper, MIS is understood in a broad sense. MIS's scope is of a very wide range from each application system to system innovation view. The MIS should support the firm's objectives, and, consequently, MIS evaluation should be implemented at corporate level, not merely at application system level. The most critical problem of MIS evaluation is that a systematic frame covering various viewpoints and factors of MIS evaluation does not exist. Not a single measure covers all aspects of MIS evaluation. To help resolve this problem, this paper proposes an hierarchical approach for practical use that includes most aspects of evaluation approaches from previous studies, and, furthermore, emphasizes the evaluation of strategic aspects of MIS.

• 한국컴퓨터정보학회논문지
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• 제5권4호
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• pp.154-160
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• 2000

최근 정보기술의 급격한 발달과 함께 정보시스템의 개념과 역할에도 많은 변화가 나타나고 있다. 더불어 정보시스템의 효과적인 관리와 운영을 위해서는 보다 체계적인 MIS 평가가 요청되고 있는 실정이다. 이전부터 MIS 평가에 관한 많은 연구들이 이루어져 왔으나, 관점의 다양성과 MIS의 도입성과의 포괄성으로 인해 MIS 평가를 위한 사용자 만족도가 개별 시스템에서 산출되는 결과물에 대한 평가로 국한되어왔다. 이에 본 연구에서는 기존의 MIS 평가에 관한 연구들을 기초로 변화된 MIS를 종합적으로 평가할 수 있는 개념적인 프레임워크를 제시하였다. 즉 MIS도입으로 인한 결과물에 대한 사용자 만족도 및 조직 전체의 변화에 대한 만족도 등 기존의 MIS 평가에서 제시된 다양한 관점과 평가방법을 종합하여 새로운 평가 프레임워크를 제시하였다.

• Journal of Information Technology Applications and Management
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• 제25권2호
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• pp.91-108
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• 2018

The purpose of this study is to examine the direction of the students' satisfaction improvement by comparison of related disciplines of undergraduate management information systems (MIS) majors. MIS is one of the academic disciplines that have become important as the demand for manpower for new industries in the 4th industrial revolution. We surveyed 3rd and 4th grade undergraduate students in the departments of management information systems, business administration (BA), computer engineering (CE) of C university. The results revealed that the students' satisfaction was influenced by the ability of the professor, the curriculum development, and the curriculum operation factors. Especially, it was found that the curriculum operating factors among the three departments had greater effect on the students' satisfaction. If the education environment is improved considering curriculum operating factors and the administrative and service factors and that are important in the CE departments, it will be helpful for the students' satisfaction improvement of MIS.

• 한국정보통신학회논문지
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• 제10권5호
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• pp.975-982
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• 2006

해양수산부는 정보통신기술발전과 정보인프라 특히 유 무선통합통신환경으로 급속히 변하고 있는 환경에 대응하기 위해서 또한, 기존의 웹 기반 Port-MIS시스템의 한계를 극복하기 위하여 최초로 모바일 기술을 활용한 모바일 Port-MIS 민원처리 시스템(이하, 모바일 Port-MIS)을 개발하여 운영하고 있다. 이 시스템은 새로운 시스템이기 때문에 서비스 초기에 많은 문제점과 저항이 있을 것으로 예상된다. 그래서 본 연구에서는 현재 신규 개발 운영 중인 모바일 Port-MIS의 활용 현황을 분석하고, 문제점과 활성화 요인을 파악하여 이를 기반으로 모바일 Port-MIS의 활성화 방안을 제시한다. 본 연구는 향후 모바일 기술 도입을 준비하는 정부기관 및 기타 기관에게 가이드라인을 제시할 수 있을 것이다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.7-8
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• 2007

This paper presents an vulnerability index for hidden failure of protective relays in transmission system. The bad influence can be quantized by an vulnerability index. When there is mis-operation, no-operation or mis-setting, power flow can be quantized by an index. According to the index, relays can be resetting. So the wide area blackout can be prevented.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2014년도 추계학술대회
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• pp.179-181
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• 2014

지금까지의 해상교통관제시스템(Vessel Traffic System: VTS)에서 관제를 수행함에 있어서 관제사들이 확인할 수 있는 선박에 대한 정보는 AIS(Automatic Identification System) 정보에 한정적이었다. 하지만 선박에서 전달받는 AIS 정적 정보는 한정적이며, 정확성 역시 신뢰할 수 없을 경우가 많은 실정이다. 그래서 관제사들은 선박의 정확한 정보 확인을 위해서 항만운영시스템(Port-MIS)에 별도로 접속하여 해당 선박에 대한 정보를 조회하여 활용하는 상황이다. 현재 ETRI에서는 Single Windows 개념을 적용한 차세대 해상교통관제시스템을 개발하면서 관제사들의 편의성 제공을 위해 추가적인 Port-MIS의 연동 없이 관제 화면을 통해 관제중인 선박에 대한 Port-MIS 정보를 조회하여 현시할 수 있도록 개발하고 있다. 본 논문에서는 관제사들의 VTS 현시용 선박 정보 필드에 대한 요구사항을 도출하고, 이를 제공하기 위한 시스템 설계 구조에 대해서도 기술한다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2004년도 추계학술대회 논문집
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• pp.1303-1308
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• 2004

This paper proposes a reduction method for the mis-operation analysis of the DC High Speed Circuit Breaker(HSCB) in electric railway substation system. The analysis method is based on present condition of operation which is a method for accuracy level up. There is reason to operation of HSCB that it is mis-operation of fault detection relay(50F), operation of ground fault relay(64P), and trouble of electric car. A countermeasure is relay resetting through field test, induction of GTOCB(Gate Turn Off Thyristor Circuit Breaker), HSVCB(High Speed Vacuum Circuit Breaker), coordination with electric car. The results presented in the paper can be used as a reference for maintenance free in electric railway substation system.

• Journal of Advanced Marine Engineering and Technology
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• 제12권1호
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• pp.28-36
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• 1988

Since the oil shocks of 1970s, the quality of the fuel oil for marine diesel engines has become more degarded than ever. When the poorer quality fuel is burned, carbon residues of the fuel oil cause blockage of the fuel injection valve nozzle and troubles of fuel injection system. The mis-firing of engine occurs due to the decrease of fuel quantity injected, the decrease of compression pressure in the slow speed range, the increase of fuel leaked and the high ignition temperature of degraded fuel etc. This paper is to investigate theoretically the effects of mis-firing on the crankshaft axial vibration of diesel engine. The cylinder pressure in operation is calculated by the computer aided simulation of closed cycle for a large two-stroke diesel engine and also the exciting force of axial vibration and the resonance amplitudes are calculated. And then, the condition of normal state, misfiring and one-cylinder cut-off operation are analyzed. The results of calculations show good agreements with those of the actual measurements.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2003년도 추계학술대회 논문집 전력기술부문
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• pp.337-340
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• 2003

This paper describes the operational characteristics of protection algorithm applied in distributed generations(DG) for faults occurred in the interconnected distribution networks. The DG can be Influenced by abnormal grid conditions such as disturbances occurring in the neighboring distribution feeders as well as the interconnected power line. Particularly, in case of the fault happening in the neighboring distribution feeders emanated from the substation to which DG is connected, the protective devices in the DG might mis-operate. The mis-operation of protective devices can be varied by the fault conditions. The simulation results for Hoenggye substation model composed of five feeders using PSCAD/EMTDC showed that the number of mis-operation of protective devices applied in DG is about 0.66 times per one year.