• 전력전자학회:학술대회논문집
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• 전력전자학회 2008년도 하계학술대회 논문집
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• pp.538-540
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• 2008

본 논문은 조명용 RGB LED 구동 장치를 위한 새로운 방식의 Two-stage RGB LED 구동 회로를 제안한다. 제안된 회로는 PFC Flyback Converter의 다중 출력을 이용하여 LED 구동 회로의 전압 스트레스를 줄이면서 효율을 높일 수 있는 새로운 방식의 LED 구동회로이다. 제안된 회로는 Universal Input에서 25W 이상 조명 장치에 적용되는 IEC61000-3-2 Class C 규제를 만족하며, RGB LED의 개별적인 Digital Dimming을 사용하여 다양한 색을 구현할 수 있다. 본 논문에서는 제안된 회로의 동작 원리를 설명하고, 시뮬레이션 및 RGB LED에 실제 적용 실험하여 제안 회로의 유용성을 입증하였다.

• 산업기술연구
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• 제24권A호
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• pp.75-81
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• 2004

The metal halide lamps are now widely used in the application and commercial lighting due to their attracting properties such as good color rendering and high efficiency. But, they have the serious problem of acoustic resonance for high frequency operation and they need the high voltage to ignite. So, they have not been applied to indoors. Over the past few years, a considerable number of studies have been conducted on the electronic ballast together with hot restarting and resonance phenomenon. But, very few attempts have been made with the adaptive ignition method according to the lamp state. In this paper, electronic ballast is proposed for metal halide lamps with an igniter for adaptive ignition. The proposed electronic ballast can generate different ignition voltages according to the arc tube state.

• 소성∙가공
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• 제21권2호
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• pp.131-137
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• 2012

With the advantages of power savings, increased life expectancy and fast response time over traditional incandescent bulb, LEDs are increasingly used for many applications including automotive, aviation, display, and special lighting applications. Since the high heat generation of LED chips can reduce service life, degrade luminous efficiency, and cause variation of color temperature, many studies have been carried out on the optimization of LED packaging and heat sinks. In this study, a fin expansion type cooling device using heat pipe, instead of a solid aluminum heat sink, was designed for LED security lightings based on thermal resistance analysis. Numerical analysis and experimental validation were carried out to evaluate its cooling performance.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2008년도 International Meeting on Information Display
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• pp.1116-1119
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• 2008

We developed phosphorescent white OLEDs with high efficiency and color stability. By engineering device architecture in which confined excitons within the emissive layer by using adequate interlayer and balanced recombination of charge carriers by using stepwise hole transporting layer system, these WOLEDs showed power efficacy of 43.6 lm/W with CRI = 62 and 36 lm/W with CRI = 72 at $100\;cd/m^2$ without outcoupling enhancements.

• 전력전자학회논문지
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• 제8권3호
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• pp.260-265
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• 2003

태양의 고도와 방위각에 따라 태양광 발전 시스템의 에너지량이 차이가 많이 난다. 본 연구는 소규모 독립형 시스템인 가로등에 맞는 경제적인 추적장치 개발에 관한 것이다. 위치추적시스템은 프로그램을 사용한 방식으로서 시스템을 기존 유사 시스템에 비해 저가화를 실현하였다. 개발된 태양 위치 추적 시스템을 가로등에 적용하여 고정식과 추적식의 에너지량을 일정 기간 동안 실측 비교한 결과 평균 86%의 효율개선 효과를 보았다.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• 제4B권1호
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• pp.24-28
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• 2004

Metal halide lamps have been made suitable for use in outdoor illumination systems over many years. They are also widely used in application and commercial lighting due to their attracting properties such as good quality color, rendering and high efficiency. Over the past few years, a considerable number of studies have been conducted on the electronic ballast with hot restarting and resonance phenomenon. However, very few attempts have been made at the adaptive ignition method according to lamp state. This paper proposes an electronic ballast for metal halide lamps with an igniter for adaptive ignition. The proposed electronic ballast can generate different ignition voltages according to the arc tube state. The experimental results showed that the proposed ballast circuit using adaptive igniter is suitable for 70W HQI lamps.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 추계학술대회 논문집 Vol.17
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• pp.644-647
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• 2004

Recently, the environmental problem has received considerable attention. so, many lamps have been developing for environmental requirement and energy efficiency, also, at glow discharge lamp researchers try to reduce energy spending that is power saving lamp. this kind requirement agree with strong points of electrodeless fluorescent lamp has received to now lighting sauce. In this paper, at the research and development of Electrodeless Fluorescent Lamp phase, according to ferrite C.F.D(Computational Fluid Dynamics) Simulation and lamp brightness character are measured to find optimization design requirements of RF antenna which is impotent for emission of lamp.

• 한국공간구조학회논문집
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• 제4권2호
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• pp.107-115
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• 2004

보도육교의 목적과 의미는 매우 다양해 질 수 있다. 현대교량은 지역을 연결한다는 단순기능외에도 주위환경을 고려한 기능적 미적, 기술적 고려사항들을 담고 있다. 이러한 다각적인 교량의 역할을 가능하게 하는 설계개념을 모색하였다. 그리고 이들 다양한 설계개념을 교량에 반영하는 방식을 고찰하기 위하여 해외 창의적인 교량의 사례들을 살펴보았다.

• Elastomers and Composites
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• 제50권1호
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• pp.1-6
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• 2015

Polybutadiene rubber (BR) has been well known that its physical and chemical properties are changed when it is exposed to ultraviolet light undergoing photooxidation. In this study, photooxdiation process of BR vulcanizate was investigated using a high pressure mercury lamp used as an outdoor lighting, which has high UV radiation efficiency and reasonable cost. Discoloration and crack formation of photooxdized BR vulcanite surface were examined using an image analyzer. Change of chemical functional groups of BR vulcanite surface by photooxidation was investigated using ATR-FTIR, and variation of the crosslink density with the UV irradiation time was investigated. By increasing the UV irradiation time, the crosslink density steeply increased after a period of time and did not increase any more. Formation of hydroxyl (~OH) and carbonyl (~C=O) groups on the BR vulcanizate surface increased and the1,4-cis unit was converted to the 1,4-trans unit as the photooxidation was proceeded.

• 한국가구학회지
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• 제26권4호
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• pp.334-345
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• 2015

The social design, which appeared at the end of the 19th century, is getting attention along with problems in modern society. The purpose of this paper is to analyze several cases of social furniture designs, and to present its necessity and future direction. It classifies the cases of furniture, lighting and design project regarding social design into three types. First is furniture design for social minority. Second is sustainable design, and third is social design that delivers social message. The expected effects of social design are cost-efficiency, sociality, and environment-friendliness. Also, social design requires certain direction which is first; the designer should recognize the minorities in the world. Second, the designer is obliged to accomplish social mission, and last, he or she should be aware that the design creates added values.