• Proceedings of the IEEK Conference
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• 1998.10a
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• pp.533-536
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• 1998

The electrical characteristics of NMOSFETs with asymmetrical source/drain regions have been expermentally investigated using test devices fabricated by $0.35\mu\textrm{m}$ CMOS technology. The performance degradation for asymmetric transistor and its causes are analyzed. The parasitic resistances, such as series resistance of active regions and silicide junction contact resistance, are distributed in parallel along the channel. Depending on source/drain geometry, the array of those resistances is changed, that results the various electrical properties.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 1993.04a
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• pp.136-145
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• 1993

This paper considers a reliability problem as a special type of flow problem and presents an algorithm to evaluate the exact 2-terminal reliability of networks by using a backtracking technique. It employs a polygon-to-chain reduction in addition to series and parallel reduction techniques to reduce execution time. In comparisons, it presents a much better performance than other algorithms known to us. We also propose a methodology to apply the algorithm for approximation of the system reliability.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 1992.11a
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• pp.51-55
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• 1992

By using the state plane approach, the steady state analysis and design of a half bridge parallel-series (LLC-type) resonant converter (HBPSRC) operating in the continous conduction made is presented. The state-plane diagram representation of the converter response gives good insight into the converter operation. Based on this analysis, a set of steady state characteristic waves for HBPSRC is presented. A simple design procedure is given and design example for a 100watts, 30KHz HBPSRC is presented for illustrative purposes.

• Proceedings of the KIPE Conference
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• 2000.07a
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• pp.509-512
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• 2000

LCD displays for flat monitors the backlit using Cold Cathode Flourescent Lamps(CCFLs) In this paper a low-cost series resonant half-bridge inverter for LCD backlight is proposed as a CCFL ballast. It is regulated by asymmetric control for its fixed frequency soft switching model. The attractiveness of this topology is primarily its low cost because of using BJT switches and reduction of anti-parallel diode. Design procedure and experimental verification from 5W 15"LCD backlight are presented.

• Proceedings of the KIEE Conference
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• 2003.04a
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• pp.300-302
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• 2003

Fluorescent lamp converts electrical energy Into light energy. Generally we use both electronic ballast and glow starter method in the house. We developed 40W electronic starter and its characteristic is verified by experiments. The efficiency of ballast is improved by using the LC Parallel reasonance circuit at input stage and LC series reasonance circuit at out-put stage.

• Proceedings of the Korean Society for Quality Management Conference
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• 2006.11a
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• pp.105-109
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• 2006

MTTR and MTBSF are two representative quantitative maintainability and reliability requirements for railway systems. we deal with the redundancy allocation problem to satisfy the two requirements. The redundancy increases MTBSF and changes MTTR. Parallel redundancy and the exponential lifetime distribution of components are considered for the series systems. Mathematical model and example are presented for the redundancy optimization problem of minimizing the cost subjecting to MTTR and MTBSF requirements.

• Proceedings of the KIPE Conference
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• 1999.07a
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• pp.110-113
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• 1999

본 연구에서는 고주파 유도가열을 위한 전원장치에 사용되는 인버터 시스템의 대용량, 고조파화를 실현하기 위한 고주파화 기술을 제안하였다. 부한 공진 인버터는 H형 전-브리지(Full-Bridge)로 구성하고 각 암당 IBGT를 2병렬로 조합하여 구성하고 부하는 직병열 공진회로로 구성한다. 스위칭 동작은 8개의 IGBT중 각 ARM당 2개씩 순차 제어하여 고속 대용량의 고주파 전력을 출력시킨다. 또한 스위칭은 스위치 턴온·오프시에 스위칭 손실을 줄이기 위해 ZVS(Zero-Voltage Switching) 기법을 도입한다. 제어는 고정주파수 PWM(Pulse Width Modulation) 제어를 하여 전력변환 효율을 극대화한다.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.54 no.2
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• pp.91-96
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• 2005

In this letter, we proposed a novel DGS (Defected Ground Structure) microstrip resonator. The proposed DGS resonator has the resonant and anti-resonant characteristic that is very similar to those of a SAW resonator or a FBAR. In order to confirm the validity of the proposed resonator, we designed and implemented bandpass fitters by using series ana parallel resonators.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2006.05a
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• pp.107-109
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• 2006

직렬-병렬 시스템의 중복설계 문제는 비용, 무게등을 고려한 다양한 제약 조건하에서 시스템의 신뢰도를 최대화하기 위해 하부시스템의 중복설계의 최적 개수를 결정해주는 것이다. 일반적으로 이 문제는 다루기 힘든 NP-hard 문제로 분류된다. 특히 Coit과 Smith가 제시한 문제에 대해 유전자 해법 등의 다양한 발견적 해법(Heuristic methods)들이 개발되었으나 이 문제에 대한 전역 최적해(Globally optimal solution)는 아직 알려져 있지 않다. 따라서 본 논문에서는 기존의 해법들이 다루었던 이 문제에 대한 전역 최적해를 구하여 그 성능을 비교하고자 한다.

• Proceedings of the KSR Conference
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• 2007.05a
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• pp.809-815
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• 2007

This paper proposes the analysis on new equipment for power quality in electrified railway. The proposed equipment consists of series and parallel inverter. Each inverter is connected by capacitor as dc link. This structure can be compensated for active and reactive power in catenary through transformer.