• Journal of the Korean Institute of Telematics and Electronics S
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• v.34S no.7
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• pp.9-18
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• 1997

In this paper, we implemented the communication module in the Telephone Network Access Subsystem(TNAS) of the Advanced Communications Processing System(ACPS). We defined some kinds of communication tasks and related resources like several queues which are executed in real-time operating system, and implemented the procedures for processing the user information. Through traffic modeling and simulation, the performance of the Service Processing board Assembly(SPA) is evaluated in the aspets of system utilization and buffer size. The ACPS should accommodate various public networks such as public switch telephone network, packet switchen data network, frame realy netork, and ATM network. The communications module proposed in this paper could be used inthe interface beween the SPA and the High Speed Network Adaptor of other network interface subsystems.

• Proceedings of the KIPE Conference
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• 2016.07a
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• pp.135-136
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• 2016

본 논문은 무손실 스너버를 갖는 부스트-플라이백 역률보상 컨버터 기반의 단일 스위치 AC-DC LED(Light Emitting Diode) 드라이버를 제안한다. 제안된 LED 드라이버는 높은 역률을 얻기 위한 부스트 역률 개선 회로와 전기적 절연을 위한 무손실 스너버를 갖는 DC-DC 플라이백 모듈로 구성된다. 무손실 스너버에 의해 스위치의 서지 전압 스트레스는 감소하며 누설 인덕터의 에너지가 DC 링크 커패시터에 저장되어 재사용된다. 또한 낮은 정격 전압의 DC 링크 커패시터를 사용할 수 있다. 제안된 컨버터는 이론적 해석과 100[W]급 하드웨어 시작품을 제작하여 검증하였다.

• Proceedings of the KIPE Conference
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• 2003.07a
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• pp.93-96
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• 2003

Korea Multi-Purpose SATellite (KOMPSAT) uses software-controlled unregulated bus system In which the main bus is directly connected to a battery and the duty-ratio for PWM switch is generated by the on-board satellite software algorithm. In this paper, we propose a new power-stage circuit that can be available for modularization of a solar array regulator(SAR) which is used in the KOMPSAT. The operations at each mode and current sharing characteristics of the power-stage are analyzed and verified by simulation and experiments on a prototype converter.

• Proceedings of the KIPE Conference
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• 2017.11a
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• pp.121-122
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• 2017

ITER AC/DC 컨버터(Converter)는 핵융합 발생을 위해 토카막의 초전도코일에 제어된 전류를 공급하여 플라즈마 발생, 형상 유지, 소멸하는 기능을 한다. 만일 컨버터 또는 초전도코일에 이상이 발생하면 즉시 보호동작이 실행되어야 한다. 이를 위해 설계된 F-LIC(Fast Local Interlock Controller)은 즉시 작동하여 Bypass 및 Make Switch 트리거, 차단기 작동 등을 순차적으로 수행한다. ITER Interlock System의 기기는 중요성이 고려되어 높은 신뢰도가 요구된다. 본 논문에서는 F-LIC 회로분석과 Telcordia SR-332 Standard에 의한 부품고장률 산출방법을 사용하여 FMEDA를 분석하고, 이를 통하여 회로구성 부품의 고장이 미치는 영향과 F-LIC 제어모듈의 SIL-2 등급의 적합성을 분석하였다.

• Proceedings of the KIPE Conference
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• 1999.07a
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• pp.663-666
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• 1999

This paper describes a three-phase converter with high power factor using a scheme of discontinuous current mode(DCM). The proposed system can replace the conventional diode bridge with step-up chopper which is used as a converter for adjustable speed drive. In this system, the current of reactor is zero at turn-on instance because of operation in DCM, while the switch turns off at the instance of maximum current. A soft-switching scheme with lossless snubber was proposed. Therefore, a zero-voltage switching at turn off can be achived by lossless snubber and zero-current switching at turn on can be obtained by operating under DCM. A theoretical analysis and computer simulations with PSpice were done to verify the operation of the proposed system. Also a prototype of hardware system was built and tested for verifying the feasibility of proposed system.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.3
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• pp.427-432
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• 2012

In this paper, we have designed and fabricated 7-bands (GSM 850/900, DCS/PCS, and UMTS 3 bands) LTCC front end module (FEM) embedded LPF (low pass filter) to efficiently eliminate harmonics generated in TX path. The proposed FEM is composed of flip-chip typed CMOS SP9T switch to select transceiver signals, dual type SAW filters to receive Rx signals, and 0603 size chip components for the antenna matching and ESD protection. The whole size of FEM is $4.5{\times}3.2{\times}1.2mm^3$. The insertion loss of Tx and Rx ports are measured at 1.7 dB and 4.8 dB, respectively.

• Proceedings of the Korean Information Science Society Conference
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• 1999.10c
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• pp.596-598
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• 1999

교환기 소프트웨어 개발에 많은 언어가 사용되고 있으나, 현재 우리나라의 교환기 제조업체 대부분은 ITU-T에서 통신 소프트웨어 개발 언어로 권고하는 CHILL 언어를 사용하고 있다. CHILL은 엄격한 타입 검사, 구조적 프로그래밍, 모듈화, 병렬 처리 기능을 특징으로 하고 있다. LG정보통신에서는 이러한 CHILL 프로그램의 시험 및 디버깅을 위하여 GNU Debugger(GDB)를 기반으로 CHILL 교차 디버거인 LGDB(LG Debugger)를 개발하였다. LGDB는 현재 사용 중인 대부분의 마이크로 프로세서를 지원하며, 호스트에서 개발한 프로그램들이 교환기 시스템과 같은 목적 시스템 상에서 정상적으로 실행되는지 검사하고, 만약 오류가 발생하였을 경우 이를 추적하여 수정하는 기능을 제공한다. 점차 대용량화, 고성능화가 요구되고 있는 교환기 개발 프로젝트의 추세를 감안할 때, LGDB는 교환기 소프트웨어의 품질 및 생산성 향상에 매우 높은 기여를 할 것이다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.25 no.10B
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• pp.1722-1731
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• 2000

In this paper we proposed a new type of the Optical Cell Compressor and Decompressor which are essential modules in TDM of TDM/WDM Hybrid OPtical ATM Switch structure. This proposed structure frastically lessens hardwares for realization by using SOA gates and optical feedback loops in the process of compression and decompression. Also it is able to compress and decompress the large capacity optical pulse stream just with a few of stages cascade connected. We proved it's possibility for systematic application through 4-bit compression experiment.

• Proceedings of the KIEE Conference
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• summer
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• pp.1537-1539
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• 2004

This paper introduces a supplementary module reducing the standby-power of Power Line Communication(PLC) modem, one of the network equipments that take up much of the stand-by power. This supplementary module consists of three parts, such as a compare part, a control part, and a switch part. This supplementary module controls the power going from the power supply element into PLC modem, which brings about the effect of standby-power reduction. It is assured that over $30\%$ standby-power reduction is estimated when we applied this module to a low-speedy PLC control modem.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2009.05a
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• pp.321-323
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• 2009

When power failure occurs at multi-housing complex, auxiliary generator or emergency generator starts to provide power to households. This power is connected to emergency power ELB(Earth Leakage Breaker) at home distribution panel board and supplies power only for emergency light in living room but for heating system, refrigerator and other inevitable apparatuses that are in need of uninterruptible power. Since those domestic appliance are fed from common power line, they are inoperable during power failure. Our research is to resolve this problem by developing compatible relay-drive common/emergency-power ATS (automatic transfer switch) for home distribution panel board. In case of power failure, it transfers automatically and commences to provide power from emergency generator. Through this, Consumers can reach satisfaction where common power loads operate without any problem under both ordinary and power failure condition.