• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.11a
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• pp.1002-1005
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• 2000

The goal of this study is to develop a linear DC motor with high thrust, speed and stiffness for machine tool. In the first phase of this study, We has made a pilot model and measuring system. Using the measuring system, We could finished the performance test of the pilot model, which continuous thrust is 1, 391N. Experimental values agree with the theoretical results well. In a certain sense, We are expecting the realization of linear motor with continuous thrust of 6, 000 to 7, 000N next time.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38A no.11
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• pp.955-966
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• 2013

We propose two feedback interference cancellers(FICs) to improve the performance of the equalization digital on-channel repeater(EDOCR) with the FIC for the ATSC DTV broadcasting system. The FIC estimates the feedback channel between Tx. and Rx. antennas of the repeater by cross-correlating the reference signal and the feedback signal. Since there is a DC pilot which ruins the white property of the ATSC DTV signals, the FIC cannot estimate the feedback channel accurately. To solve the problem, the structural method which uses an additional DC pilot free reference for feedback channel estimation and the algorithmic method based on the digital signal processing which whitens the ATSC DTV signals and performs the feedback cancellation in the whitened signal domain. Simulation results show that the proposed two FICs show better feedback cancellation performance than the conventional FIC.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.50 no.2
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• pp.73-78
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• 2001

With the increasing demands for clean environment, development of air cleaning systems has been received increasing attention. One of the key technologies in the electrostatic precipitator(EP) is high voltage pulsed power supply, which affects the performance of the overall system. In this study, a high voltage microsecond pulse power supply for the pilot EP is developed. The power supply has a dc source and a pulsed one. The ratings of the dc and the pulse source are 60kV and 70kV respectively. The width of pulse voltage is 140us and the maximum pulse repetition frequency is 200Hz.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.478_479
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• 2009

It is important to find the maximum efficient conditions for the output of the photovoltaic(PV) system to determine the optimal installation location of the PV system. The output of PV system depends on the irradiance. Therefore, this paper introduces the pilot experiment set to track the output of PV system according to the variance of irradiance and analyzes the result of experiment using this set. The pilot experiment set consists of the PV modules and the inverter to convert DC power to AC power. For this experiment, the fixed and tracked modules are used.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.5
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• pp.900-905
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• 2008

I perform bit error rate(BER) analysis of orthogonal frequency division multiplexing(OFDM) systems impaired by both direct current(DC) offset and carrier frequency offset. By analyzing the BER performance for real OFDM systems employing 16-quadrature amplitude modulation(QAM) and pilot symbol estimation, the dependency of BER on the DC offset and carrier frequency offset is quantified and compared to ideal performance. Results show that the magnitude of frequency offset and DC offset are required to be less than 0.01 and 0.007, respectively.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.23 no.4
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• pp.815-820
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• 1998

A new coding algorithm which has spectrum notches at the DC and Nyquist Frequency for maximizing the effect of the in-band pilot insertion in order to make the symbol timing or carrier recovery easy is proposed. It is shown that this algorithm uses one encoder and gives the similar spectrum characteristics to that of the existing OF00 code which uses two encoder. In this paper, the proposed new coding algorithm is explained andits spectrum characteristics is compared with the of OF00 code using computer simulation.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.38 no.2
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• pp.128-136
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• 2001

This paper evaluates the performance of an optic link in a frequency conversion based fiber-radio system. The proposed link structure simplifies a BS(base station) via making the MMW(millimeter wave) optical pilot tone generated in the CS(control station) be used in the uplink as well as in the downlink. To acquire the optical pilot tone, an EOM(electro-optic modulator) in the CS is biased in three different ways, i.e., MAB(maximum bias), MIB(minimum bias), QB(quadrature bias). We, depending on the biasing of the EOM, evaluate the link performances in two cases; one is for constant laser source power and the other for constant received DC optical power at a PD(photo detector). Based on the simulation results on the downlink CNR and the uplink SFDR(spurious free dynamic range), we finally deduce the effective EOM biasing for each case.

• Proceedings of the KIEE Conference
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• summer
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• pp.174-176
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• 2004

FACTS 기술은 송전계통에 전압원 인버터를 설치하여 모선 전압과 전력조류를 제어하므로 송전용량 증대 및 계통 안정도 향상을 가능케하는 신기술이다. 국내에서는 2003년 최초의 FACTS Pilot Plant인 80MVA UPFC가 154kV 강진 변전소에 설치되었다. UPFC는 STATCOM과 SSSC가 DC 커패시터를 통하여 결합된 구조로 되어 모선전압과 유효/무효전력 조류의 독립적인 제어가 가능하며 계통 운전 상황에 따라 STATCOM과 SSSC의 단독운전 또한 가능하다. 따라서 STATCOM 및 SSSC 단독운전시의 계통영향에 대한 분석이 필요하다 본 논문은 EMTDC 모델을 이용하여 현재 운전중인 강진 변전소 UPFC의 직렬 운전모드인 40MVA SSSC의 제어특성과 운전효과 분석에 대하여 기술하였다.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.840-843
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• 1997

We applied a DCS which was developed in Korea to test furnace. Test furnace is a pilot-scale plant made for finding combustion in firing coal. In this paper, we describe control system which was implemented in test furnace in detail. Finally, we describe the fire box temperature control loop, and show fire box temperature control result during commissioning stage using implemented control system.

• The Transactions of the Korean Institute of Power Electronics
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• v.16 no.6
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• pp.533-541
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• 2011

This paper studies modeling of Jeju 80kV HVDC system and its controller by using PSCAD/EMTDC program. Reduced ac network is applied to verify interaction between ac network and dc system. Design parameter is applied to the converter transformer, harmonic filter and dc transmisstion line to simulate dc system. HVDC controller is divided into a rectifier controller and a inverter controller according to the converter operating mode. The inverter controller is composed of current control, voltage control and extingtion angle control. The rectifier controller is composed of current control and voltage control. Both controller has VDCOL characteristics so that current order is dependant on voltage variation. Step response, ac network single phase fault, three phase fault is simulated to verify the dynamic performance of controller model in both transient state and steady state.