• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제54권5호
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• pp.245-252
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• 2005

The fuel cell systems are one of very useful energy sources. The systems have advantages as renewable and environmental sources. To obtain AC components from fuel cells, it needs inverters. A multilevel converter is used as a power conversion system for a high power fuel cell system. Through harmonic analysis, it is shown that the harmonic components and THD increase while a fundamental component of output decreases as voltage droop increases. To solve the voltage disturbance problems, three different approaches are investigated in this paper; installation of a boost converter at the fuel cell output, control of pulse widths, and use of ultracapacitors. The proposed three approaches are analyzed and compared through simulation and experimental results.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2005년도 춘계학술대회논문집
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• pp.337-341
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• 2005

Most utiltity systems are subject to frequent changes, often due to increased loads and demand to up-grade quality of service provided. Urban renewal, expressway construction and suburban growth have also caused significant changes in urban utility distribution systems. Recently, it is required that a guideline for planning of a complete system, the reasonable design and construction methods for the efficient installation common utility tunnels must be estabilished. It prompts drastic measures to guard cities and their inhabitants against the horror of massive fires in the future. Preparedness holds the key to safety.

• 한국정보과학회:학술대회논문집
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• 한국정보과학회 2004년도 봄 학술발표논문집 Vol.31 No.1 (A)
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• pp.670-672
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• 2004

유ㆍ무선 및 방송 그리고 인터넷의 망 통합을 염두에 둔 차세대 통신망은 다양한 유형의 단말기 보급과 더불어 새로운 서비스 창출에 대한 필요성이 대두되었고 인터넷 기반의 응용 소프트웨어를 개발하는 방법에 대한 진화가 정보 기술 쪽에서 진행되고 있다. 소프트웨어를 통합하여 비용을 절감하며, 서로 다른 도메인에서 개발된 기능들이 결합된 새로운 응용들을 개발하는 방법론으로서 Web Service 개념이 도입되고 있다. 인터넷에서의 Web Service 기술 적용 시도에 비슷한 시점에 전기통신 분야에서도 표준화 기관들인 ETSI. 3GPP 및 Parlay를 중심으로 통신망 자원들을 사용하기 쉽도록 개방하여 통신 시장에서의 잠재적 신규서비스들을 창출하려는 활발한 노력의 결과 개방형 Parlay/OSA API들을 표준으로 규격화하였으며 최근에 전기통신 분야에 친숙하지 않은 IT 개발자들을 통신 시장에 대거 흡수하여 IT 기술을 전기통신 분야에 접목시키려는 노력의 일환으로 Parlay X Working Group은 Parlay/OSA API들을 더욱 추상화시키기 위한 시도를 하고 있다. ［9］ 본 논문에서는 Parlay Gateway 와 Parlay X Gateway 그리고 Web Service를 개발하여 웹 서비스 기반의 개방형 통신 서비스의 활성화방안에 대해서 기술한다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 A
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• pp.319-320
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• 2006

At this study, one of the electrical problems, arc characteristics according to loss of contact between a pantograph and a catenary, was analyzed. A characteristic of arc current is disappeared in a short period of time. Nevertheless, it has large current same as a surge, so that it has EMI/EMC problems. In the case of the electrical railway system, there is oscillation and de-wiring. The are current is generated by these problems. The result of this study can be used as a facility design to prevent a surge and needs to prove through actual field data in the main circuit of an electric train for a precise analysis about effect of are.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.1165_1166
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• 2009

In recent years, energy prices have soared, which of course have increased costs for railway operators. Simultaneously, the energy market has considerably changed that in most developed countries, it is deregulated, giving railway operators an opportunity to define new ways of using energy. Efficient operation of the railway system is considered as an essential way to energy saving while an efficient management of power level helps to lower the reference subscribed power, giving access to better energy rates. It is studied on the relation between time and force for the energy efficient driving of train in railway when the train is braking according to several slips.

• 한국조명전기설비학회지:조명전기설비
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• 제8권2호
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• pp.41-45
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• 1994

본 논문은 MRA PWM 기법을 응용한 Sub-MRA PWM 기법을 디지털 신호 처리용 프로세서를 이용하여 구현하였다. Sub-MRA PWM기법을 디지털 신호처리 함으로서 아날로그의 불안정한 요소를 감소시킬 수 있었다. 이를 검증하기 위하여 시뮬레이션을 통하여 고조파를 분석하였다. 디지털 제어의 단점인 시간 지연은 고속 연산을 이용하여 극소화 할 수 있었다. 그러므로, 유도, 전동기를 실시간으로 제어할 수 있었다.

• 전기학회논문지
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• 제56권4호
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• pp.751-755
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• 2007

We have studied the variable conditions of reactive sputtering to prepare AM thin film. The leakage current showed below $10^{-9}A/cm^2$ at the deposition temperature of $250^{\circ}C\;and\;300^{\circ}C$ in the field of 0.1 MV/cm, and it was gradually increased and to be saturated in 0.2 MV/cm. The C-V characteristics of the above mentioned deposition temperature conditions showed a deep depletion phenomenon at inversion region. The C-V characteristics showed similarly under the DC power conditions of 100 and 150 W but were degraded at 200W. When the DC power was 100, 200, and 300 W the dielectric breakdown phenomenon was shown in 2.8, 3.2 and 5.2 MV/cm, respectively. It was found that AIN film was dominated by Poole-Frenkel conduction mechanism.

• 한국조명전기설비학회지:조명전기설비
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• 제10권6호
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• pp.54-61
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• 1996

본 논문에서는 기존에 제시된 영전압 준공진 buck dc-dc 컨버터를 시뮬레이션을 이용하여 분석하고, 이에서 발생하는 문제점을 분석하였다. 그리고 부하저항을 낮게 가변함에 따라 소자의 스트레스가 증가함을 확인하였다. 그 원인이 freewheeling다이오드의 기생 커채시턴스에 의한 전압상승에 의하여 발생함을 확인하고, 이를 개선할수 있는 영전압 스위칭 컨버터를 제시한다.

• 한국조명전기설비학회지:조명전기설비
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• 제9권6호
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• pp.78-82
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• 1995

It is needed to robust control for D.C. servo motor according to industrial automation. However, when a motor has an effect of disturbance and variable load, it is very difficult to guarantee the robustness of the system. as a compensation way of solving this problem, in this paper, a expert supervisory control method for motor control system is presented. Expert supervisory controller is designed by error and error change, and nth control input is decided by the addition of (n-1)th control input and inference amount of increase or decrease. Control input of expert supervisory control is transmitted to input, and the disturbance effect decrease remarkable by control input. The robustness of D.C. servo motor using expert supervisory control is demonstrated by the computer simulation.

• 조명전기설비학회논문지
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• 제27권6호
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• pp.82-87
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• 2013

Electrical leakage happens when faults in electrical apparatus or power lines occur. It causes electrical fires and electric shocks. In order to reduce accidents caused by electrical leakage current, it is important to detect faults effectively and shut off the power. In this paper, firstly we analyzed statistics of electrical fires and electric shocks caused by electrical leakage current. Secondly, standards of allowable leakage current and body impedance models were analyzed. Lastly, effective application methods for breaking electrical leakage current were suggested. The results will provide useful preventive measures of electrical fires and electric shocks caused by electrical leakage.