• Proceedings of the KIEE Conference
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• 2005.07a
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• pp.387-389
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• 2005

Scott 결선 변압기는 3상전원에서 단상부하를 공급해야하는 계통에서 많이 사용되고 있다. 특히 전기철도가 이에 해당되며 국내에서는 전기철도의 화장으로 Scott변압기가 154kV급의 송전계통에 연계되어 설치 운전되고 있다. Scott변압기의 특성상 단상인 부하측 또는 3상인 전원측에서 사고 발생시 각상에 흐르는 불평형 사고전류의 예측이 어려워 관련기기의 선정과 각종 보호계전기의 정정이 쉽지 않았으며 과도현상 해석도 쉽지않았다. ATP(Alternative Transient Program)는 전력계통의 과도현상뿐만 아니라 단락 및 지락과 같은 정상상태 해석 및 고조파 분석도 가능하며 그래픽 유저 인터페이스를 위한 ATPDraw도 개발되어 데이터 입력과 사용법이 보다 간편하게 되었으며, 출력파형을 위한 PlotXY도 개발되어 계산결과를 다양한 형태의 그래프로 출력할 수 있게 되었다. 무엇보다도 User Group에 가입하면 무료로 모든 프로그램을 사용할수 있는 장점도 있다. 본고에서는 ATP를 사용하여 Scott변압기의 모델링과 이를 통한 단락 및 지락 사고 둥의 해석 사례를 소개하였다.

• Proceedings of the Korean Society of Disaster Information Conference
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• 2016.11a
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• pp.167-170
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• 2016

본 논문에서는 실패한 구조물에 초점을 맞추어 조사를 진행하였다. 실패한 구조물은 구조적, 역학적, 환경적 부정합으로 인해 구조물이 붕괴된 경우로 인명 피해가 발생한 것으로 정의하였다. 삼풍백화점과 성수대교의 국내 사례와 방글라데시 라나 플라자, 미국 미시시피 강 교량의 국외 사례를 통하여, 각각의 붕괴사고의 원인을 규명하였으며, 붕괴사고의 해결책을 모색하고 체계적으로 분석하였다. 본 연구를 통하여 구조물의 붕괴 뿐 만이 아니라, 다방면의 재난을 예방 및 방지할 수 있는 연계 시스템의 확립 또한 강조하였으며, 사고방지를 위해 변화하는 시방서 및 기준에 대하여도 언급하였다.

• Proceedings of the Korean Society of Computer Information Conference
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• 2012.07a
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• pp.163-166
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• 2012

본 논문에서는 퍼즐을 활용하여 초등정보영재교육 방안을 제안하고자 한다. 현재의 정보영재 교육과정을 살펴보면 프로그래밍학습과 알고리즘 학습에 치중하고 있다. 이것은 직접 체험하고 조작하며 학습하는 초등학생의 특성상 효과적인 방법이 아니다. 따라서 흥미와 재미의 요소를 포함하고 정보교과의 부담을 줄여주며 논리적인 사고력을 향상시켜줄 수 있는 퍼즐을 활용한 초등정보영재교육을 제안한다. 또한 최근 컴퓨터 과학에서 강조하고 있는 계산적 사고(Computational Thinking)와 퍼즐활용교육과의 관계를 살펴보고 퍼즐활용 교육을 통해 계산적 사고를 기를 수 있음을 제시한다. 추후에 초, 중, 고 정보영재교육을 연계를 위한 퍼즐 교육에 많은 연구가 필요하다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2019.11a
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• pp.65-67
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• 2019

해양활동의 급속한 확대로 해마다 발생하는 해양사고의 발생이 증가하고 있으며, 사상자 수도 비례적으로 증가하고 있다. 이러한 사고를 줄이기 위해서, 다양한 구조 요청 기기가 개발되고 제시되되어 왔으나 단일화 되지 못한 통신 방법, 구조 요청 과정에 대한 사용자의 인식 부족으로 실질적인 구조 요청 장치의 사용율이 지극히 낮다. 또한 해양의 특수성으로 인하여 제시되어온 기기를 이용하기 위해서는 큰 비용이 소요되었다. 이에 따라 실질적인 구조 가능성을 높이고 해양사고로 인한 사상자를 최소화하기 위해 본 연구의 목적은 실험평가와 경험적 공식을 바탕으로 일반 사용자가 손쉽게 접근 가능한 안드로이드 애플리케이션과 연결된 자동 구조 요청 장치를 개발한 것으로, 본 연구는 현장 및 실험실 시험의 결과에 근거하여, MOB 구출을 위한 자동 구조 요청 장치의 사양을 확정 검증하는 실용화 연구를 수행하였다.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.18 no.1
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• pp.98-104
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• 2004

This paper represents the fast and efficient load transfer guide for fault or outage restoration in distribution system. For restoration guide, system trace is performed to reverse direction(source side) from tie breaker in tree-structured distribution network. Search space and breaker's combinational number for restoration guide are greatly reduced. It is proposed the load transfer method including first stage restoration(single load transfer, double load transfer, triple load transfer), second stage restoration(transferring load to neighboring feeder in order to expand the capacity margin) and load cutoff guide. The proposed method can be easily applied to primary customer restoration, multi-fault recovery and distribution automation system.

• Journal of the Korean Institute of Gas
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• v.7 no.2 s.19
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• pp.42-47
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• 2003

To prevent major accident from toxic gas release, explosion, or fire in chemical processes, it needs dynamic control of human error with mechanical failure. Although most of major accidents occur with a coupling of human error and mechanical failure, numbers of researches have studied human error and mechanical reliability independently, but no where cross each other, to reduce the risk in the process. This work focuses on the coincidence of human error and mechanical failure for management of human error, and on some important performance shaping factors to propose a method for improving safety effectively of the process industries.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.3
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• pp.1288-1295
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• 2012

Korea Ministry of Knowledge Economy has estimated that wind power (WP) will be occupied 37% in 2020 and 42% in 2030 of the new energy sources, and also green energies such as photovoltaic (PV) and WP are expected to be interconnected with the distribution system because of Renewable Portfolio Standard (RPS) starting from 2012. However, when a large scale wind power plant (over 3[MW]) is connected to the traditional distribution system, protective devices (mainly OCR and OCGR of re-closer) will be occurred mal-function problems due to changed fault currents it be caused by Wye-grounded/Delta winding of interconnection transformer and %impedance of WP's turbine. Therefore, when Double-Fed Induction Generator (DFIG) of typical WP's Generator is connected into distribution system, this paper deals with analysis three-phase short, line to line short and a single line ground faults current by using the symmetrical components of fault analysis and PSCAD/EMTDC modeling.

• Journal of the Korea Convergence Society
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• v.2 no.2
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• pp.47-56
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• 2011

Korea Ministry of Knowledge Economy has estimated that wind power (WP) will be occupied 37% in 2020 and 42% in 2030 of the new energy sources, and also green energies such as photovoltaic (PV) and WP are expected to be interconnected with the distribution system because of Renewable Portfolio Standard (RPS) starting from 2012. However, when a large scale wind power plant (over 3[MW]) is connected to the traditional distribution system, protective devices (mainly OCR and OCGR of re-closer) will be occurred mal-function problems due to changed fault currents it be caused by Wye-grounded/Delta winding of interconnection transformer and %impedance of WP's turbine. Therefore, when Double-Fed Induction Generator (DFIG) of typical WP's Generator is connected into distribution system, this paper deals with analysis three-phase short, line to line short and a single line ground faults current by using the symmetrical components of fault analysis and PSCAD/EMTDC modeling.

• Communications of Mathematical Education
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• v.30 no.2
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• pp.161-178
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• 2016

Mathematics problem based learning(PBL), which has recently attracted much attention, is a teaching and learning method to increase mathematical ability and help learning mathematical concepts and principles through problem solving using students' mathematical prerequisite knowledge. In spite of such a quite attention, it is not easy to apply and practice PBL actually in school mathematics. Furthermore, the recent instructional situations or environments has focused on student's self construction of their learning and its process. Because of this reason, to whom is related to mathematics education including math teachers, investigation and recognition on the degree of students' acquisition of mathematical thinking skills and strategies(for example, inductive and deductive thinking, critical thinking, creative thinking) is an very important work. Thus, developing mathematical thinking skills is one of the most important goals of school mathematics. In particular, recently, connection or integration of one subject and the other subject in school is emphasized, and then mathematics might be one of the most important subjects to have a significant role to connect or integrate with other subjects. While considering the reason is that the ultimate goal of mathematics education is to pursue an enhancement of mathematical thinking ability through the enhancement of problem solving ability, this study aimed to implement basically what is the meaning of the integrated thinking ability in problem based learning theory in Mathematics. In addition, using historical materials, this study was to develop mathematical materials and a sample of a concrete instructional guideline for enhancing integrated thinking ability in problem based learning program.

• Journal of Korea Water Resources Association
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• v.53 no.11
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• pp.1015-1024
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• 2020

Recently, water pollution accidents have continued to occur in pipelines such as red water Incheon and Seoul. In order to recognize this water quality problem, it is necessary to install a water quality sensor in an appropriate location and measure it in advance to detect or block the water supply to the water faucet of the shelter. However, there are limitations, such as maintenance costs, to installing multiple water meters in all pipelines. Therefore, this study proposed a methodology for determining and prioritizing the installation location of flow-based water quality sensor for the recognition of water quality problems in pipelines. We applied the proposed procedure to the pipe break scenario. The results of the determination of the location of the water quality sensor were presented by applying it to the pipe network that actually operates the emergency pipe in Korea. The result of the decision showed that in the event of abnormal situation caused by the destruction of individual pipes, the flow rate of the pipes around the aqueduct and the tank may change rapidly, resulting in water quality accidents caused by turbidity. In the future, it is expected that the water quality monitoring point selection method, such as establishing an external pipe operation plan for pipe cleaning, will utilize the procedure for determining the location of the water quality sensor according to the velocity.