• 대한전기학회:학술대회논문집
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• 대한전기학회 1990년도 하계학술대회 논문집
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• pp.121-124
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• 1990

Distance relaying is one of the most commonly used protection schemes in the high voltage transmission systems. In this scheme, coordination between the primary and backup relays is very critical for the power system security. This paper reports an rule-based methodology for checking and correction of miscoordination problems in the distance relaying. Diagnosis rules achieving an accurate but simple checking have been developed through the geometric analysis of the impedance characteristics of the distance relays. Heuristic rules having the pratical power for miscoordination correction are suggested. The proposed method has proved very effective through the several case studies on the actual systems.

• 분석과학
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• 제8권4호
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• pp.499-503
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• 1995

In order to study how and why the stabilities of lanthanoid(III) complexes in solutions vary across the series, the formation constants of the adducts of tris(2-thenoyltrifluoroacetonato)lanthanoids(III) with seven carboxylic acids in chloroform have been determined by solvent extraction technique at 298K. The formation constants with carboxylic acids generally decrease with increasing the atomic number, but in the middle of the series, they change only slightly. Such trends have been interpreted as related to a change of the coordination number in the middle of the series. It has been attempted to determine the number of water molecules coordinated to the adducts as well as $Eu(TTA)_3$ in chloroform by measuring the fluorescence life time of europium(III), to ensure the assignment of the coordination number.

• 대한전기학회논문지:전력기술부문A
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• 제49권4호
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• pp.143-151
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• 2000

Electric power distribution feeders are susceptible to faults caused by a variety of situations such as adverse weather conditions, tree contacts, equipment failure, accidents, etc. Distribution circuit faults result in a number of problems related to the reliability of service and customer power quality. In the distribution line, the permanent interruption of customer service resulting from a blown fuse or a recloser lockout was the only factor which was used to determine service reliability. On underground distribution line, the serving of cables by earth-moving equipment is a prevalent cause of faults and the most cable faults quickly develop into bolted current. we introduce th multi-circuit breaker coordination methods in the Underground Distribution Line.

• Journal of Electrical Engineering and Technology
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• 제12권3호
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• pp.1245-1249
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• 2017

Recently, unusual transformer failures have been reported in 25kV power systems connected with a VCB and transformer. In this study, performance of the protection system, dielectric strength of the transformers, characteristics of switching surges and resonance phenomena were analysed and assessed. All investigations regarding the insulation breakdown of the transformers were carried out by simulations, laboratory tests, factory tests and on-site measurements in order to thoroughly investigate the root causes. Furthermore, experimental methods for investigating the resonance phenomenon were derived and tests were conducted applying the derived method to recreate the phenomenon in the transformer. It is found that resonance between the transformer and switching surge generated by closing a VCB can initiate the breakdown of internal windings of a transformer.

• Bulletin of the Korean Chemical Society
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• 제25권4호
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• pp.581-583
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• 2004

• Bulletin of the Korean Chemical Society
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• 제33권12호
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• pp.4251-4254
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• 2012

• 정보보호학회논문지
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• 제22권2호
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• pp.249-258
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• 2012

최근 사이버 테러는 국가와 민간을 넘나들며 그 경계가 제한되지 않고 있으며, 현대전의 양상은 사이버 공격을 활용하여 관련 정보를 유출하고 그 정보를 악의적으로 이용하여 국가 및 기업에 치명적인 피해를 끼치고 있다. 이에 정부는 2008년 7월 25일부터 지식경제부 산하 공공기관의 보안과 사고예방을 위하여 지식경제사이버안전센터를 운영하고 있다. 지식경제사이버안전센터는 보안관제센터로서 사이버공격 정보를 탐지 분석하여 즉시 대응 조치를 수행하고, 수집 탐지한 정보를 국가 사이버안전센터 및 회원기관과 공유한다. 또한 정보공유분석센터(ISAC, Information Sharing & Analysis Center)로서 전자적 제어 관리시스템을 포함한 주요정보통신기반시설에 대한 취약점분석 및 평가를 실시하고, 침해사고대응센터(CERT/CC, Computer Emergency Response Team/Coordination Center)로서 보안사고 예방활동 및 보안사고 대응서비스를 수행하고 있다. 이에 본 논문에서는 나날이 그 역할이 커지고 있는 지식경제사이버안전센터의 설립 목적 및 역할, 수행업무에 대한 서비스를 분석하고 문제점을 파악한 후에 개선 방안을 제시한다.

• Journal of Positioning, Navigation, and Timing
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• 제10권4호
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• pp.235-242
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• 2021

Unmanned Aerial Vehicles (UAVs), which were used for military purposes, are gradually expanding their application fields under the influence of electrification and digitalization. Starting from the field of aerial imaging and Intelligence Surveillance and Reconnaissance (ISR) mission, nowadays the possibility of Urban Air Mobility (UAM), which transports passengers and cargo with drones, is widely under discussion. In order to occupy the rapidly growing global unmanned aerial vehicle market in advance, it is necessary to secure core technologies and develop key UAVs components based on the new technologies. In the navigation field, it is necessary to secure a precise position with guaranteed reliability and continuity, unrelated to the operating environments. The reliability and continuity should be secured in the algorithm level and in the H/W component levels also. In order to achieve this technical goal, the Ministry of Science and ICT has launched the 'Unmanned Vehicle Core Technology Research and Development Program' in 2019 to support the R&D on the unmanned vehicle technologies. In this paper, authors introduce the unmanned vehicle core technology research and development program to the related researchers. The authors summarize the backgrounds of the program and show the technological tasks and objectives on the sub-programs in the unmanned vehicle navigation program. We present the program schedules especially focused on the test and evaluation of the developed technologies and components.

• Bulletin of the Korean Chemical Society
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• 제25권10호
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• pp.1564-1566
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• 2004

• Bulletin of the Korean Chemical Society
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• 제27권1호
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• pp.137-139
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• 2006