• 센서학회지
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• 제29권3호
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• pp.149-155
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• 2020

In this study, we employed Manchester code for illumination control and flicker prevention of the light-emitting diode (LED) used in a visible light communication (VLC) system. In the VLC transmitter, the duty factor of the Manchester code was utilized for illumination control; in the VLC receiver, the spike signal from an RC-high pass filter was utilized to recover the transmitted signal whilst suppressing the 120-Hz noise arising from adjacent lighting lamps. Instead of the clock being transmitted in a separate channel, a syncmark signal was transmitted in front of each data byte and used as the reference time for transforming the Manchester code to non-return-to-zero (NRZ) data in the receiver. In experiments, the LED illumination was controlled in the range of approximately 12-84% of the constant wave (CW) light via changing of the duty factor from 10% to 90%. This scheme is useful for constructing indoor wireless sensor networks using LED light that is flicker-free and presents capability for illumination control.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 1995년도 학술대회
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• pp.87-90
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• 1995

In this paper, we propose a new deinterlacing algorithm based on weighted wide vector correlations. This algorithm is developed mainly for the format conversion problem encountered in current HDTV system, but not limited to. By having wide vector correlations, visually annoying artifacts caused by interlacing, such as a serrate line, line crawling, a line flicker, and a large area flicker, can be remarkably reduced, since the use of wide vector correlation increases the detectability of edges in various orientations.

• 전기학회논문지
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• 제57권11호
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• pp.1946-1953
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• 2008

Power system of Jeju is interconnected to the mainland using HVDC and that is also interconnected to three wind farms. It will be difficult to control of Jeju power system if HVDC is disconnected or HVDC is overhauled under large scale wind farms interconnected. We measured and analysed the power quality of two substation and two wind farms to assess that wind farms have an effect on Jeju system during the HVDC overhaul last May. We concentrated on the power quality like frequency, voltage variation, voltage harmonics, current harmonics, flicker. We can found that the frequency of Jeju system is very unstable during overhaul, so the frequency of Jeju system can be variated easily by wind farm's rapid output power variation. There are some benefits and weak points in power quality between two wind farms because each wind farm is consist of different wind turbines.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 추계학술대회 논문집 학회본부 A
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• pp.229-231
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• 1999

This paper deals with electromagnetic transient modelling of wind power system embedded in distribution networks. Wind power system consists of induction generator link reactor, distribution line, and controlled load unit. The introduction of embedded wind power system presents a new set of conditions to networks both with respect to power quantify needed to be transported and power quality such as sag swell, very short interruption, and flicker. This paper investigates the transient behavior of voltage, frequency, and load flow in wind driven induction generation system embedded in distribution networks.

• Journal of Electrical Engineering and Technology
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• 제1권2호
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• pp.153-160
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• 2006

This paper presents a new compensating system, which consists of a shunt active filter and passive components for mitigating voltage and current disturbances arising from an Electric Arc Furnace (EAF). A novel control strategy is presented for the shunt active filter. An extended method based on instantaneous power theory in a rotating reference frame is developed for extraction of compensating signals. Since voltages at the point of common coupling contain low frequency interharmonics, conventional methods cannot be used for dc voltage regulation. Therefore, a new method is introduced for this purpose. The passive components limit the fast variations of load currents and mitigate voltage notching at the Point of Common Coupling (PCC). A three-phase electric arc furnace model is used to show power quality improvement through reactive power and harmonic compensation by a shunt active filter using the proposed control method. The system performance is investigated by simulation, which shows improvement in power quality indices such as flicker severity index.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2005년도 International Meeting on Information Displayvol.I
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• pp.499-501
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• 2005

One of representative techniques for compensation of LC's slow response characteristic is the Response Time Acceleration (RTA) technique. The conventional data definition for the RTA is based on the manual measurement and thus it takes long time. Therefore it is almost impossible to use panel specific compensation data in MP line. We have developed a new automated measurement system and flicker minimization for this purpose, which could achieve dramatic measurement time reduction, consistency over different operator, and optimized values as well. This system laid the groundwork for the application of image quality enhancement technologies to panels individually, and using this system, we can expect very uniform image quality for all LCD panels.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2008년도 춘계종합학술대회 A
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• pp.734-737
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• 2008

본 논문은 새로운 형태의 TFT-LCD 자동 화질 최적화 시스템을 제안한다. 또한 참조 감마 곡선과의 6-점 프로그램 정합 기술을 이용한 새로운 알고리즘 및 자동 전압 설정 알고리즘을 제안한다. 이러한 시스템은 평균 감마 오차, 감마 조정 시간 및 플리커 등을 줄이기 위해 모바일 LCD 구동 IC 내의 감마 조정 레지스터들과 전압 설정 레지스터들을 자동적으로 제어한다. 개발된 알고리즘과 프로그램은 범용 LCD 모듈에 적용 가능하다. 제안된 최적 화질 향상 시스템은 측정 대상이 되는 모듈 (MUT, LCD 모듈), 제어 프로그램, 휘도 측정용 멀티미디어 디스플레이 측정기 및 인터페이스용 제어 보드로 구성되어 있다. 제어 보드는 DSP와 FPGA로 구성되어 있고, RGB 및 CPU와 같은 다양한 인터페이스들을 지원한다. 개발된 자동 화질 최적화시스템은 기존의 시스템에 비해 현저히 짧은 감마 조정시간, 적은 플리커 및 적은 평균 감마 오차를 보였다. 본 논문에서 제안하는 시스템은 최적 감마 곡선 및 자동 전압 설정을 이용하기 때문에 개발 공정 시간을 단축시키고, 고화질의 TFT-LCD를 제공하는데 아주 유용하다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2005년도 추계종합학술대회
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• pp.861-864
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• 2005

Performing accurate and repeatable low frequency noise measurement is critical for modeling and simulation of flicker noise. Through the accurate and repeatable on-wafer measurement, low frequency noise characteristics of the 0.18 ${\mu}m$ n-MOSFETs are discussed. And on-wafer flicker noise measurement system is presented. The on-wafer measurement system consists of cascade probe station, low noise current amplifier (SR570), and dynamic signal analyzer (HP35670A).

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2005년도 춘계종합학술대회
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• pp.387-390
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• 2005

전 세계는 국제 시장의 개방화로 인하여 해상을 통한 수${\cdot}$출입 컨테이너 화물량이 크게 증가하고 있다. 이에 선박이 항해 중 가장 중요한 것은 자선의 위치를 정확히 파악하여 안전하고 경제적인 항로를 이용하여 효과적으로 운항을 도모하는 것이다. 따라서 본 논문에서는 선박의 안전한 운항을 도모하기 위해서 항만, 연${\cdot}$근해에 설치되어 있는 무인등대의 효율적인 관리를 위한 자동 점멸 시스템의 설계에 관한 연구이다. 본 시스템은 GPS를 통한 일출과 일몰 시간의 동기화와 다른 해양 환경 조건을 고려하여 광센서와 습도센서를 추가 이용하여 무인 등대의 자동 점멸 시스템을 설계 및 구축한다.

• Journal of Power Electronics
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• 제14권4호
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• pp.754-763
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• 2014

In this paper a method for the development of a static VAR compensator (SVC) control algorithm is presented. The proposed algorithm has been designed with the objective of eliminating the negative impact of electric arc furnaces on the power system. First, a mathematical model of the proposed SVC controller in the d-q synchronous rotating coordinate system is developed. An analysis under dynamic and steady state conditions is also carried out. The efficiency of the presented controller is demonstrated by means of computer simulations of an actual steel-factory network model. The major advantages of the proposed controller are better flicker compensation, increased ability to regulate voltage and the need for only one-point network measurements.