• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.9
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• pp.1584-1588
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• 2007

This paper proposed the voltage compulsion method that used chopper for light dimming control of fluorescent lamp. During the dimming period, electronic ballasts have the bad characteristics such as low power factor, high THD(Total Harmonic Distortion) and etc. The proposed dimmer improves power factor, THD of electronic ballast and has benefit such as low cost, simple build up.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2011.11a
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• pp.360-363
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• 2011

카메라 촬영시 LED방송조명 등기구를 조도 디밍하는 경우에 카메라 셔터속도가 빨라 질 경우, 카메라가 신호를 감지하며 카메라 영상에 플리커 현상이 생기게 된다. 그 현상을 없어지게 하기 위하여 LED 디머의 PWM속도를 충분히 높여주어서 카메라 셔터속도가 빨라져도 어느 정도 범위에서 감지하지 못하도록 하였다.

• Proceedings of the KIPE Conference
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• 2007.07a
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• pp.470-472
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• 2007

현재 수요가 꾸준히 증가하고 있는 디지털 디머 시스템은 국내 연구가 미비한 실정이다. 이러한 시점에 본 논문은 현재까지 개발한 디지털 디머 시스템과 그 기능을 소개하고자 한다. 개발한 시스템은 크게 콘솔과 디머 랙으로 나눌 수 있으며, 콘솔은 사용자와의 인터페이스와 전체 디머 시스템의 제어가 주목적이며, 디머 랙은 콘솔로부터 전송받은 각 조명 레벨을 위상각 제어 방식으로 조명기기의 밝기를 제어하도록 설계하였다.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.13 no.4
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• pp.47-53
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• 2013

Nowadays, Advanced country have devised a plan energy-saving through lighting effectiveness and increasing performance of lighting control system. If it uses the LED as a source of light then conserve electricity by 50%. This paper implement LEMS(Lighting Energy Management System) that applicate and Smart Dimmer and Smart Switch that control the digital LED light, support wired-wireless communication using USN(Ubiquitous Sensor Network). This system of validity and reliability control special purpose lamp including indoor and outdoor lighting and landscape lighting effectively. It minimize the use of indoor and outdoor lighting energy by USN remote integral control function of Digital System Lighting of LED and increase effectiveness of energy and is a collaborative system that can feedback the use of electricity by measurement itself through Web and Switch.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2003.11a
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• pp.148-153
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• 2003

The influence of sizing, fiber and pigment type on coating penetration, using commercial paper and two types of handsheets as the base paper which were prepared from thermomechanical pulp(TMP) and hardwood bleached kraft pulp(KP) sized internally with alkyl ketone dimmer(AKD), was studied in terms of characteristics of coating holdout. Laboratory rod draw down coater was used for surface sizing and coating application. Characterization of coating penetration was done by measuring the roughness of the backside of coating layer. The backside of the coating was exposed by dissolving the fibers in a solution of cupriethylenedimine(CED). Data show that internal sizing of base paper is effective and surface sizing is more effective to prevent coating penetration. Comparing between the two types of base papers, backside roughness of coating layer of TMP sheet is much larger and sizing is more effective to reduce coating penetration than those of KP sheet. With regard to pigment type, clay is more effective than calcium carbonate for better coating holdout.

• Journal of the Optical Society of Korea
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• v.14 no.2
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• pp.152-162
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• 2010

This study examined the effects of surround luminance on the shape of the spatial luminance contrast sensitivity function (CSF). The reduction in brightness of uniform neutral patches shown on a computer controlled display screen is also assessed to explain the change of CSF shape. Consequently, a large amount of reduction in contrast sensitivity at middle spatial frequencies can be observed; however, the reduction is relatively small for low spatial frequencies. In general, the effect of surround luminance on the CSF appears similar to that of mean luminance. Reduced CSF responses result in less power of the filtered image; therefore, the stimulus should appear dimmer with a higher surround luminance.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.54 no.4
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• pp.161-165
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• 2005

Need of a dimmer function becomes more important with increasing interest on a HDTV for home theater applications. In a conventional AC PDP, a possible method to reduce luminance of a whole Panel is to reduce a total number of sustain pulses and then to change the gray level. However, the reduction of the total sustain number causes the step of luminance to be rough. Moreover, it is impossible to control the luminance of the panel for a given gray level. In this paper, a simple and robust method is proposed to control linearly the luminance of whole panel by applying the asymmetric sustain pulses in the display period of the ADS driving scheme. As the range of luminance control by the proposed method is about $50\%$ for a given gray level. Moreover, it is experimentally verified that the proposed method shows similar dynamic margin performances compare with the conventional method.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.283-283
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• 2010

Smart street light controller is a product with advance micro controller base for energy saving in conventional street lighting systems. Intelligent Street light controller are specially developed for automation and energy saving in conventional street light systems and lighting systems. It is so designed that it operates on sunrise & sun set timings according to longitude of particular location with facilitate to set month wise civil twilight timings to cope up with all seasons. Dimming (Power down) mode selection switch on/off at fixed times with relay or contactor. Night dimming, staggering and intelligent control reduces burn hours and increases the lifetime of lamps with about 30% and low annual operating cost type base are among the most inexpensive wireless technologies available. Low initial costs As PLC wireless, there is no need to establish cable connection.

• JSTS:Journal of Semiconductor Technology and Science
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• v.16 no.1
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• pp.1-10
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• 2016

Drivers for LED MR16 retrofit lamps need to be compatible with the dimmers and electronic transformers which originally operated with the halogen lamps to be replaced. We present a two-stage MR16 LED driver consisting of a boost converter in the first stage and a buck converter in the second stage. Our design has been analyzed in the frequency domain using simulations to demonstrate that it effectively suppresses the high-frequency components of the AC output of the electronic transformer. Experiment results with a driver prototype verify the simulation results as well as dimmability.

• The Bulletin of The Korean Astronomical Society
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• v.42 no.2
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• pp.47.4-48
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• 2017

In the middle of $19^{th}$ century, the Seong Gyeong 星鏡, which is a Korean historical astronomy book, was published by Nam Byeong-Gil(1820-1869). In this study, identification was conducted by considering the star catalogue recorded in the Yixiang Kaocheng Xubian 儀象考成續編. The Seong Gyeong 星鏡 recorded the information of 1,449 stars, and identified 1,413 stars among 1,449 stars, which is a rate of 97.5%. The positional error (angular distance) of the identified stars is $5.33{\pm}0.34$ arc-min. It was also confirmed that the magnitudes of the recorded stars have correlations with those of modern times. It was determined that the position error of the stars became larger as the magnitude of the stars became dimmer, or as the position of the stars came closer to the pole. Based on these analyses, the Seong Gyeong 星鏡 was confirmed that it is a result of correcting the precession of the selected stars from star catalogue of Yixiang Kaocheng Xubian 儀象考成續編.