• Proceedings of the KIEE Conference
• /
• 2008.11a
• /
• pp.250-252
• /
• 2008

DC traction system generates leakage current because running rails are used in return circuit. And it is very important to estimate the leakage current to the train operation situation. Therefore this paper presents dynamic simulation technique that is very similar to the real operation situation using TPS and PSCAD/EMTDC. For this we model DC traction system included in DC substation, variable feeding circuit model and variable train model. And we extract train location and power using TPS program and use these data for dynamic simulation. Finally we can estimate leakage current to the various operation condition using dynamic simulation.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
• /
• 2004.11a
• /
• pp.305-308
• /
• 2004

There are ground facility of maintenance in house electric facility of infra maintenance electric home appliances having used multifariousness in house, that use electric energy of common source for equipment. The body of building such as the reinforced concrete construction is structurally united, and the electric resistance is also small. It is possible that those foundations have contacted the ground at large surface area and that it substitutes the building construction body for the earth electrode. This is called "the structure earthing". This method has been defined at electrical facilities technical standards and KS in our country, and it has been used in various quarters practically. However, in our country, there is no example of using the foundation of the house as substitution earth electrode practically, and the means of the evaluation as electrode has not been established either. Then, in this paper, basic research for utilizing foundation of the house as substitution earth electrode is carried out.

• 한국정보통신설비학회:학술대회논문집
• /
• 2007.08a
• /
• pp.159-162
• /
• 2007

최근 IPv6 기반 WiBro 망에서 다수의 사용자가 동종망간 혹은 이기종망간 인터넷 연결을 유지하면서 그룹으로 이동하는 상황에서의 핸드오버 처리 폭증 및 핸드오버 지연 시간 문제를 효율적으로 해결할수 있는 기술 및 시스템이 요구되어 지고 있다. 본 이동 AP는 IPv6 기반 WiBro 망에서 다양한 광대역무선망 접속 및 다양한 하향 단말 접속이 가능한 하드웨어 기반에 네트워크 이동성 기술를 구현하여 IPv6 기반 WiBro 네트워크 실, 내외 환경에서 이동성을 지원하지 않는 다수의 단말들이 네트워크 이동시 각 단말들의 이동성 처리가 수행됨을 확인하였으며 관련 서비스 연속성이 유지됨을 시험을 통해 확인 할 수 있었다.

• Proceedings of the KIEE Conference
• /
• 2011.07a
• /
• pp.2212-2212
• /
• 2011

현재 국내의 경우 설비의 열화 상태 및 그 경향을 파악하여 부적합한 상태를 파악하기 위한 다양한 상태판단 기술이 개발되고 있다. 본 논문에서는 전기철도 DC 전력설비 과부하 상태판단 기술과 설계 방향에 관하여 기술하였다. 또한 실용적 리뉴얼 방향과 실용적교체 기준의 국내외 기법을 조하하여 이를 적용하기 위한 기술연구를 수행하였으며 이를 바탕으로 도시철도 전력설비의 실태진단을 위한 노후화 시스템 교체 기준 수립의 기초 연구 및 기본 조사 방향이 되고자 하였다.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
• /
• 2005.05a
• /
• pp.467-472
• /
• 2005

In this paper, design and control of the novel SEPIC-Flyback converter(SF converter) is developed as a possible converter for fuel cell system. This output characteristic of SF converter is similar to Buck-Boost converter in that it can step-up or step-down the voltage. With the small signal equivalent circuit modeling of SF converter, control-to-output transfer function is obtained. SF converter couples up the inductive type converter to capacitive type converter with one transformer, which has less ripple current than its respective one does. To verify the validity of the proposed converter, 500W, 100kHz converter is designed and tested. ZVS switching and active clamping are also tested in practice.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
• /
• 2005.05a
• /
• pp.355-358
• /
• 2005

The electrical characteristics for applying the foundation of the house to the substitutional earth electrode was reviewed fundamentally. In order to measure the earth resistance in the foundation of the house, it was performed to investigate the effect of the electrode arrangements and configurations concerning to grounding methods, and tried to the adequate simulation for comparing those experimental data. The number of steel rods and the ground resistivity were affected to change the earth resistance, but the latter caused the large variation in its resistance compared to the former in this experiment. Since the large surface area in the foundation of the house have contacted the ground usually, it is possible to use the earth electrode substitutionally.

• Annual Conference of KIPS
• /
• 2001.10b
• /
• pp.1593-1596
• /
• 2001

블루투스는 1 개의 마스터와 최대 7 개의 슬레이브로 구성되는 피코넷과 다수의 피코넷으로 구성되는 스캐터넷의 형성이 가능하여 이를 이용한 ad hoc PAN 네트워킹에 대한 연구가 시작되고 있다. 본 논문은 블루투스 피코넷에서의 ad hoc 네트워킹을 위한 GloMoSim 기반 시뮬레이터를 이용하여 ad hoc 라우팅 알고리즘을 피코넷에 적용한 시뮬레이션 결과에 관한 것이다 ad hoc 라우팅 알고리즘으로는 AODV와 DSR을 사용하였으며, 피코넷을 이루는 슬레이브의 개수를 1 개에서 7개까지 변화시면서 마스터-슬레이브와 슬레이브-슬레이브 간의 데이터 전송에 대한 성능을 평가 하였다.

• Proceedings of the KIPE Conference
• /
• 2011.07a
• /
• pp.208-209
• /
• 2011

본 논문은 SRM의 센서리스 속도제어를 위한 슬라이딩 모드 자속관측기법을 적용하고, 동일한 센서리스 추정방식으로 초기 기동에서 센서리스 영역까지의 천이 구간에서 오픈루프 속도리플을 억제할 수 있는 방식을 제안한다. 제안된 방식에서 센서리스 위치추정은 슬라이딩으로 자속관측기를 적용하고 있지만, 자속 계산에서 위치오차를 감소하기 위한 오차 성분을 고려하였으며, 특히 초기기동에서 동일한 관측기와 계산된 자속의 오차 성분으로 오픈루프 상태에서의 전류제어를 수행함으로써 천이구간에서의 속도리플을 억제할 수 있다. 제안된 방식은 컴퓨터 시뮬레이션을 통하여 타당성을 검증하였다.

• Annual Conference of KIPS
• /
• 2017.04a
• /
• pp.816-819
• /
• 2017

Current graph mining algorithms suffers from performance issues when querying patterns are in increasingly massive network graphs. However, from our observation most data graphs inherently contains recurring semantic subgraphs/substructures. Most graph mining algorithms treat them as independent subgraphs and perform computations on them redundantly, which result in performance degradation when processing massive graphs. In this paper, we propose an algorithm which exploits these inherent recurring subgraphs/substructures to reduce graph sizes so that redundant computations performed by the traditional graph mining algorithms are reduced. Experimental results show that our graph compression approach achieve up to 69% reduction in graph sizes over the real datasets. Moreover, required time to construct the compressed graphs is also reasonably reduced.

• Journal of the Korean Operations Research and Management Science Society
• /
• v.24 no.4
• /
• pp.141-156
• /
• 1999

Recently expanded and enhanced software system inevitably demands serious managerial considerations on its maintenance cost. This study proposes a systematic and thorough assessment model for software development methods to the end of maintainability, incorporation ISO 9126 quality standards-based criteria. The Analytic Network Process (ANP) is employed in our model to find the effect of any dependency among the items of the criteria and the alternative methods. This study then applies the model empirically in order to evaluate the efficacies of the Structured Method and the Objected-Oriented Method. At first, this study performs the test on the existence and direction of any dependency under the three types of assumptions, and then determines the relative dominance of the two methods.