• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1065-1066
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• 2008

2005년 8월 서울기점 54km에 위치한 고속선 신호기계실에 낙뢰가 발생함에 따라 신호기계실 내부에 설치된 방호스위치 외부회로의 전원공급용 DC/DC 컨버터가 소손 되었다. 그 결과, 폐색구간 작업자 보호용 방호스위치, 역구내 작업자 보호용 방호스위치 계전기 낙하가 발생하여 운행중인 고속선 열차의 정지 속도 코드가 차량에 현시 되었다. 이후 장애 절차에 따라 장애 유지보수가 완료되었지만, 상행선 7개, 하행선 3개 열차가 17분${\sim}$58분간 운행 지연되었다. 본 논문에서는 이러한 낙뢰 장애사고를 분석함으로서 신뢰할 수 있는 신호기계실 낙뢰 피해 방지 방안에 대해 분석하였다.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.449-450
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• 2011

본 논문에서는 실제 옥내 전력선 통신 네트워크를 기반으로 다중 사용자 환경에서의 outage probability의 변화를 확인하였다. 2명의 사용자를 가정하고 시뮬레이션을 통하여 outage probability의 변화를 확인해 본 결과 거리에 따라 최대 70% outage 확률의 변화를 확인하였다. 또한 수신부의 위치에 따라서 outage 확률이 4% 이상 차이가 난다는 것을 확인하였다.

• Proceedings of the KIEE Conference
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• 2001.07a
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• pp.81-83
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• 2001

본 논문에서는 EMTDC/PSCAD 패키지를 이용하여 배전용 정지형보상기(DSTATCOM)의 모델을 제안하였고, 이를 비선형 부하를 가지는 배전계통의 전력품질 향상을 위해 "직접" 출력전압 제어 기술을 적용하였다. 1선 지락 사고시에 본 논문에서 제시한 방법을 이용한 시뮬레이션을 통해 전압 파형이 개선되고, 고조파가 감소되며, 선로 전압 조정을 할 수 있음을 보였다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.6
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• pp.296-301
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• 2020

Three types of traffic signal systems are two-color signal systems that flash red and green and are mainly used on crosswalks, next, three-color equalization systems mainly used at T-shaped intersections with red and yellow lights and a green arrow, and third, four-color intersections that generally have red, yellow and green colored lights and a green arrow. In what is known as the "dilemma zone" area, a driver collects information that influences his/her decision whether to stop, speed, tail, interrupt, or violate a traffic light, depending on the intersection width, vehicle speed, cognitive response time and reference yellow signal time. This study examined the impact of changes in the length of the dilemma zone areas based on changes in yellow signal times, the speed of the intersection passages, and signal lamps. Downward adjustments of 50km/h and 60km/h affected yellow signal time. The yellow signal time increased by 0.1 to 2.3[s] due to this effect and the dilemma zone area increased by 1.22 to 26[m]. The driver of the dilemma zone could quickly decide to reduce the time remaining of the straight (3color, 4color) green signal to reduce the potential of a traffic accident at the intersection traffic. Safe entry of red (LED palm) and left-turn signals for entering flashed at the intersection and operated at midnight.

• Journal of the Korean Society of Marine Environment & Safety
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• v.24 no.1
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• pp.43-55
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• 2018

The biggest change in the field of coastal ship safety control since the accident of passenger ship Sewol has been the introduction of the maritime safety supervisor system. With its introduction, the safety control system in coastal passenger ships was changed from consisting of operation managers and marine police to operation managers and a newly-introduced maritime safety supervisor. The safety control system for coastal cargo ships was also converted from relying on ship inspection officers to having a maritime safety supervisor and ship inspection officers. However some negative elements have surfaced due to confusion related to the scope of work in the coastal cargo shipping field. These have been caused by dividing the supervisory agency, a lack of work continuity given non-permanent public official status, low supervisor qualifications overlooking reality, and limitations of the order for improvement to secure seaworthiness. It is essential that the maritime safety supervisor system be solidified to reinforce coastal ship safety control. Therefore, systematic safety control in the coastal cargo shipping industry should be conducted by a single, integrated government agency, and the area covered by the order for improvement to secure seaworthiness should be extended. Also limitations of the supervisor recruitment system due to non-permanent public official status should be simultaneously improved. In addition, it is necessary to upgrade supervisor qualifications to require experience with surveyors of international class, ship captains, and chief engineers.

• The Journal of the Acoustical Society of Korea
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• v.34 no.6
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• pp.432-443
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• 2015

Coherence describing the similarity between physical quantities of two signals is a very useful tool to investigate the temporal and spatial characteristics of signals propagating in underwater acoustic waveguide. Ambient noise measurements were made by the vertical received array consisting of three hydrophones as part of the KIOST-HYU joint acoustics experiment, and the coherence for the underwater ambient noise was analyzed. In this paper, the coherence results in cases that the generator in the research vessel was off and turned on are presented. The coherence estimated in the case of the generator operation mode are compared to the predictions obtained using the theoretical model with the directional density function dominated by vertical components propagating downward from the ship. In the case of the generator switch-off, the results are compared to the model predictions with directional density function including the effects of sea surface noise and long-distance shipping noise.

• Proceedings of the Korean Magnestics Society Conference
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• 2009.05a
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• pp.185-185
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• 2009

• Proceedings of the KWS Conference
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• 1997.10a
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• pp.43-45
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• 1997

• Proceedings of the Korean Information Science Society Conference
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• 2000.04b
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• pp.535-537
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• 2000

본 논문에서는 정지영상의 색상을 이용하여 객체의 영역 및 경계선을 추출하고, 각각의 추출된 정보의 정점을 혼합하여 보다 정확한 객체를 추출할 수 있는 Hybrid method를 제안한다. 그리고 이 방법을 사용하여 추출된 독립영력간의 연관관계(포함, 인접)를 파악하여 사용자가 원하는 객체를 보다 쉽게 추출하는 객체 추출 시스템을 개발한다.

• Journal of The Korean Radiological Technologist Association
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• v.29 no.1
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• pp.221-221
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• 2003