• 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 KIEE Conference
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• 2011.07a
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• pp.1195-1196
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• 2011

최근 고출력 LED의 기술적 진보에 따라 LED의 응용이 여러 분야에서 이루어지고 있으며, 무대조명은 이러한 응용분야 중 하나이다. LED를 이용한 무대 조명응용분야는 다른 LED 응용분야에 비하여 색 표현의 정확성, 색의 안정성, 제어범위 및 분해능이 중요하게 다루어지는 분야이다. 무대의 색을 연출하기 위하여 각 색의 LED를 디밍하게 되는데 디밍 방식에 따라 플리커 현상이 발생할 수 있다. 특히 PWM 디밍의 경우 방송을 목적으로 하는 무대조명에서 동영상 촬영 시 플리커를 발생시킬 수 있다. 본 논문에서는 LED 무대조명에서 발생할 수 있는 플리커에 대하여 논의한 후 플리커의 발생원인을 시뮬레이션을 통하여 분석하였다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2010.07a
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• pp.404-407
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• 2010

본 논문에서는 히스토그램 매칭(Histogram Matching)을 이용하여 고전 영화에서 화면이 깜빡거리는 현상(Flicker)을 제거하는 방법을 제안한다. 기존의 히스토그램 매칭 기반 방법은 프레임 간 물체의 움직임이 작다는 가정 하에 단순히 시공간 히스토그램 매칭을 수행하는 것이므로 움직임이 있는 부분에 존재하는 플리커는 잘 제거되지 않는 단점이 있다. 따라서 본 논문에서는 프레임 간의 차영상을 이용하여 물체의 움직임에 따른 히스토그램 매칭의 문제점을 개선할 수 있는 방법을 제안한다. 인위적으로 합성된 플리커 영상과 실제 고전 영상을 실험에 사용하였으며, 기존의 알고리즘과 비교하여 향상된 결과를 보여준다.

• Proceedings of the KSR Conference
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• 2006.11b
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• pp.1240-1246
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• 2006

Generally, there are two types of main factors to affect output power quality of a auxiliary power supply an EMU(electric multiple unit). One is a voltage flicker by amplitude modulation of short time and air compressors. The other is repetitive motion of large capacity motor such as air compressors, HVAC unit etc. in main factors. This paper compared two kinds of fluorescent lamp, 32W (after remodeling interior) and 40W(before remodeling interior) and measured the light output varying input power(AC220V) for a flicker phenomenon related power supply of lamps in EMU. Also, we analyzed a flicker considering EMU operating time and density in order to grasp main factors of a load change to cause a voltage change. As a results of test, a 40W fluorescent lamp was more insensitive with 20.26% degree an eye recognition degree sides about changes of the input power and lower with 19.9% voltage side generating flicker compare with fluorescent lamp 32W. Also, we confirmed the fact which the fluorescent lamp flicker was generated by varying fluorescent lamp output voltage when the commercial EMU was in high driving density and at the busy time. Additionally, we confirmed the frequency band which an EMU passenger could feel sensitively blinking of a fluorescent lamp was visually $8Hz{\sim}15Hz$.

• Journal of Convergence for Information Technology
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• v.12 no.2
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• pp.30-36
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• 2022

In this paper, when the lighting and communication functions of the visible light communication system are used at the same time, we propose a technique to reduce the dimming level and flicker of the lighting. Visible light communication must satisfy both communication and lighting performance. However, the existing data code method results in reducing the brightness of the entire lighting. This causes deterioration of lighting performance and flicker phenomenon. To solve this problem, in this paper, we propose an adaptive learning code allocation technique that allocates binary codes to transmitted characters and optimizes and matches the binary codes allocated according to the frequency of occurrence of alphabets in character strings. Through this, we studied a technique that can faithfully play the role of lighting as well as communication function by allocating codes so that the 'OFF' pattern does not occur continuously while maintaining the maximum dimming level of each character string. As a result of the performance evaluation, the frequency of occurrence of '1' increased significantly without significantly affecting the overall communication performance, and on the contrary, the frequency of consecutive '0' decreased, indicating that the lighting performance of the system was greatly improved.

• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2003.05a
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• pp.71-73
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• 2003

본 논문에서는 RF Matcher 의 동작성능 개선을 위하여 RF Match 제어단의 제어 알고리즘과 하드웨어의 디지털화 방안에 대한 연구를 수행하였다. 개발된 제어단은 최적의 동작성능을 위하여 multi-preset, 이득제어 기능 등 다양한 부가 기능을 갖도록 설계/제작하였고, 또한 LCD 모듈의 설치를 통하여 RF Matcher의 실시간 상태 파악이 가능하도록 하였다. 개발된 제어단에 대한 실험결과로부터 RF 전력의 over/under shoot, 플라즈마 플리커 등의 현상이 제거되었고, 정합시간이 크게 단축되었음을 알 수 있었다.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.16 no.4
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• pp.55-63
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• 2002

Meet in the internationalization period recently and van every county is progressing unionization work of every county standard with the Europe, the United States of America. If our county does not correspond actively by age, economical disadvantage is expected. Tested PC, PC monitor, printer and harmonic for device for company business of FAX 4 kinds and flicker occurrence disgrace to achieve and analyze electricity quality test for office appliances by link of confrontation in such current in treatise that see therefore. As result that test printer and PC monitor ware stable but Desktop PC and FAX are presented in valid EN standard to January, 2004 that more than limit higher harmonics and flicker phenomenon appeared, and presented countermove in reply.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.40 no.1
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• pp.240-245
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• 2015

This paper presents an impact of flicker for various binary modulations of visible light communication (VLC) under dimming requirement. While previous approaches consider the statistics of the signal that cannot capture contributions of dynamic impacts of flicker, the power spectral density is evaluated for various VLC transmission schemes of dimming support. This enables to compare transmission schemes with the contribution of low and intermediate frequency components to flicker. Numerical results show that analog dimming has advantages over other techniques in terms of flicker and signal processing with waveforms and symbol distribution allows to mitigate flicker effects.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.9 no.1
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• pp.23-29
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• 1995

There are many articles about the HID lamps about it's characteristics and simulation methods for lamp design or ballast design. For the electronic ballasts of HID lamps, There are some problems caused by acoustic-resonance which destabilizes the arc of HID lamps. So, some studies suggest the methods to avoid it. For example, the methods suggested are high frequence driving over 100[kHz], and mixed frequence driving which alternates high frequence and low frequence, and squarewave driving etc. This study suggests the electronic ballast of HID lamps that solves the problems of acoustic-resonance, and can control the luminance by constant current boostes chopper of which frequence is 30[kHz] and by the squarewave driving of which frequence is 55.5[Hz.] As follows, we have the good electronic ballast for HID lamps which has the characteristics of a light weight, and a function of luminance control and a high quality luminosity and which saves electrical energy.

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.8
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• pp.51-57
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• 2014

In this paper, we propose a novel method to effectively eliminate flickering artifacts caused by dehazing in video sequences. When applying a dehazing technique directly to each image in a video sequence, flicker artifacts may occur because atmospheric values are calculated without considering the relation of adjacent frames. Although some existing methods reduce flickering artifacts by calculating highly correlated transmission values between adjacent frames, flickering artifacts may still occur. Therefore, in order to effectively reduce flickering artifacts, we propose a novel approach considering temporal averages of atmospheric light values calculated from adjacent frames. Experimental results have shown that the proposed method achieves better performance of video dehazing with less flickering artifact than existing methods.