• Proceedings of the KIEE Conference
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• 2006.11a
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• pp.302-304
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• 2006

본 연구에서 개발한 실시간 시뮬레이터에 적용 가능한 발전단 사고 모의를 위한 정밀 모델 개발 목적은 발전단에서 발생되는 다양한 사고 중 전기적 형태로 모의 가능한 사고를 분류하고 실시간 시뮬레이터로 모의하도록 발전기 모델 및 보호계전요소 모델을 개발하여 이를 현장 실무 교육 및 훈련에 활용하기 위한 것이다. 본 연구에서는 RTDS/RSCAD로 구현 가능한 6가지 계전 요소(거리계전, 주파수, 역전력, 과여자, 과전압, 동기탈조)에 대해 모델링하였다. 그리고 보호계전기가 효과적인 보호계전을 수행할 수 있도록 계전기 신호 처리 모듈, 거리계전기 모듈, 역전력 모듈, 과여자 모듈, 주파수 모듈, 과전압 모듈, 동기탈조 모듈을 UDC를 이용하여 개발하였다. 그리고, 각 요소의 출력에 대해서 Flex Logic을 이용하여 최종적으로 계전기의 트립을 결정하는 모듈을 개발하였다. 또한 발전단 사고에 따른 발전기 보호 과정을 모의함으로써 발전회사 발전기 운전원들이 실제적인 발전기 동특성 및 발전기 보호계전기의 동작을 이해할 수 있도록 하였다.

• Journal of the Korean Society for Railway
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• v.12 no.6
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• pp.1076-1080
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• 2009

An analysis of Life Cycle Cost (LCC) is to evaluate the system through the total cost accounting during the total life cycle. Railway system has problem that abundant capital has to be utilized efficiently because railway system is a combined system such as power supply, machines, electric signals. Especially, Magnetic Levitation Train needs high technique and more study about the Life Cycle cost by using the system being developed currently in Korea. Therefore, the Modeling of Life Cycle Cost for Magnetic Levitation Train is proposed considering the tendency of the studies in other countries.

• Korean Journal of Optics and Photonics
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• v.12 no.3
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• pp.205-211
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• 2001

We propose a constant inversion black box model of erbium-doped fiber amplifiers (EDFAs) for exact performance predictions for EDFAs operated in the gain-flattened condition. The validity of the newly proposed model was experimentally verified by predicting the performance of EDFAs for the L band, within 1.9% required pump power discrepancy. The role of ion pairing effects on the power conversion efficiency is also discussed. ussed.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.9
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• pp.173-181
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• 2014

This paper addresses the problem of model matching control for a class of systems modeled as input/output asynchronous sequential machines. Based on the feedback control scheme, we design a corrective controller that compensates the behavior of the closed-loop system so as to match a reference model. Whereas the former studies use state observers and the output burst for designing a controller, the present research needs neither the observer nor the output burst in controller design. We define the 'output equivalent machine' of the considered machine to describe the existence condition and the construction algorithm for the proposed controller. A case study is provided to show the operation of the proposed corrective controller.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.25 no.4
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• pp.451-458
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• 2014

This paper introduces a bistatic ISAR imaging technique. In bistatic geometry, the transmitter and receiver are placed in different locations. The monostatic ISAR is inadequate not only for obtaining images on targets approaching along the radar's line of sight, but also for stealth targets. In this paper, geometry, signal modeling as well as bistatic Doppler for bistatic ISAR are introduced to address these problems. Simulations results show bistatic ISAR images as well as monostatic ISAR images against target's moving scenarios, and analyze their differences for each scenario.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.7 no.6
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• pp.1153-1160
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• 2003

In this paper, the performance of the UWB communication systems is analyzed in the presence of the Narrow Band Interference(NBI). UWB communication systems are modeled as using the Pulse Position Modulation(PPM). In this system, a Gaussian monocycle is used as the received pulses. The NBI is considered as a zero-mean random process with a constant spectral power density over its whole bandwidth. We obtain the mathematical expressions for describing the effect of the NBI on the UWB system. And it can be shown that the suppression of the effect of NBI on the UWB systems is available by adjusting the PPM related parameter.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.4 no.2
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• pp.417-426
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• 2000

In this paper, CE-CPSK(Constant Envelope Continuous Phase Shift Keying) modulated DS/SS(Direct Sequence Spread Spectrum) transceiver with 908 MHz carrier frequency and 1.5 MHz PN clock rate is proposed. To overcome the effect of nun-linear power amplifier, CE-CPSK modulation method which has the constant envelope and continuous phase characteristics is proposed. To analyze the DS/SS receiver performance with respect to code tracking loop, multipath fading channel is characterized as a two-ray Rayleigh fading channel. To compensate the demerit of analog delay locked loop, digital delay locked loop is employed for code tracking loop. Simulation and experimental examination has been carried out in AWGN(Additive White Gaussian Noise) and Rayleigh fading channel environment in order to prove validity of the proposed method.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2000.05a
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• pp.183-187
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• 2000

In this paper, the performance of DS-CDMA system and FH-CDMA system has been comparision analyzed in a channel environment which is characterized by Multi-User environment and Rayleigh fading environment. The techniques of improvement of the performance has been comperision analysis evaluated when adopting MRC diversity techniques. In same condition, We are analyzed the BER(Bit Error Rate) as increase Use's number due to comparing performance of two systems by Same communication band(300KHz), jamming signal(JSR) 10∼20dB, user data-rate 300bps. In the result, the performance of DS and FH systems in multiuser and Rayleigh fading environment is improved performance when adopting MRC diversity techniques. Especially DS system has been improved performance about 9.5 times than FH system when adopting MRC diversity techniques.

• Journal of the Institute of Electronics and Information Engineers
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• v.50 no.3
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• pp.212-218
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• 2013

This paper presents an SVD(Singular Value Decomposition)-Pseudo Spectrum method for SAR (Synthetic Aperture Radar) imaging. The purpose of this work is to improve resolution and target separability of SAR images. This paper proposes SVD-Pseudo Spectrum method whose advantages are noise robustness, reduction of sidelobes and high resolution of spectral estimation. SVD-Pseudo Spectrum method uses Hankel Matrix of signal components and SVD (Singular Value Decomposition) method. In this paper, it is demonstrated that the SVD-Pseudo Spectrum method shows better performance than the matched filtering method and the conventional super-resolution based multiple signal classification (MUSIC) method in SAR image processing. The targets to be separated are modeled, and this modeled data is used to demonstrate the performance of algorithms.

• Journal of IKEEE
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• v.1 no.1 s.1
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• pp.73-82
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• 1997

In this paper we analyzed, using Markov modeling, the performance of CSMA/CD over the wireless channel which is characterized by near-far effect, shadowing and Rayleigh fading. The analysis shows that throughput of CSMA/CD is degraded by channel error. However, if capture effect which arises from the randomness of power level of received signal due to the fading phenomena of electromagnetic waves is taken into consideration, the system performance is much improved and the system stability is also made better.