• 한국게임학회 논문지
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• 제10권6호
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• pp.169-178
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• 2010

본 논문은 실시간 응용 프로그램에서 사실적인 금속 재질을 렌더링하기 위한 효과적인 기법을 제안한다. 제안된 기법은 금속면의 미세한 흡집을 표현하기 위해 법선 벡터를 섭동(perturbation)하는 방법을 사용한다. 법선 벡터를 섭동하는 일반적인 방법은 범프(bump) 매핑이나 법선(normal) 매핑 등의 방법을 사용하는 것이다. 그러나 이러한 방식은 이방성 반사 특성을 갖는 표면에서는 사실적인 빛의 산란을 보이지 못한다. 금속 특유의 반사를 표현하기 위해서는 미세면 분포 함수를 이용하여 이방성 반사 특성을 모델링하는 것이 일반적이므로 일반적 법선 섭동만으로는 만족스런 결과를 얻지 못한다. 본 논문은 법선 벡터의 섭동과 함께 미세면 분포 함수를 변형하는 기법을 통해 매우 사실적인 금속면 재질 렌더링이 가능한 기법을 제안한 다. 제안된 기법은 쉽게 GPU 프로그램으로 구현되며, 실시간 환경에서 동작한다.

• 조명전기설비학회논문지
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• 제17권6호
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• pp.1-6
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• 2003

본 연구에서는 광원의 색온도와 연색성의 차이에 의한 밝음의 느낌을 연구하기 위하여 이종 램프간, 또한 동종 램프 간의 비교 실험을 시각 대상물로 흑백 인쇄문자지와 색상지를 사용하여 수행하였다. 백열전구, 형광램프, 고압 나트륨램프, 메탈헬라이드램프, 무전극 방전램프를 대상으로 실험을 수행한 결과, 이종 광원의 경우 밝음의 느낌 비는 백열전구를 제외한 광원의 경우 대체적으로 평균연색계수에 비례하는 경향이 있으며, 모든 시험 대상 광원의 경우 색온도에 비례하는 것으로 나타났다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.1623_1624
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• 2009

The use of arc tubes made of ceramic material further enhanced some of the metal halide lamp’s properties. These properties translate into higher efficacy with better color rendering, stable color through lamp long life. Recently, due to an increase in the application of the ceramic metal-halide lamp, the study for the property etc. according to Ballast's driving scheme and the study for arc tube material, optimization of gas and so on are being proceeded to improve the property of the lamp. Especially, to control ceramic metal-halide lamp, the vigorous study and practical use with respect to Electronic Ballast, which has been improved in the disadvantages of the conventional Magnetic Ballast are made. In this paper, Electrical characteristics and gas insulation destroy time are analyzed by comparing magnetic ballast with electronic ballast.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1997년도 추계학술대회논문집
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• pp.24-27
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• 1997

In the present work, rigid-plastic continuum elements employing the shape change and anisotropic effects are derived for the purpose of applying more realistic blankholding force condition in three-dimensional finite element analysis of sheet metal forming process. In order to incorporate the effect of shape change effectively in the derivation of finite element equation using continuum element for sheet metal forming, the convected coordinate system is introduced, rendering the analysis more rigorous and accurate. The formulation is extended to cover the orthotropic material using Hill's quadratic yield function. For the purpose of applying more realistic blankholding force condition, distributed normal and associated frictional tangent forces are employed in the blankholder, which is pressed normal and associated frictional tangent forces are employed in the blankholder, which is pressed against the flange until the resultant contact force with the blank reaches the prescribed value. As an example of sheet metal forming process coupling the effect of planar anisotropy and that of blankholding boundary condition, circular cup deep drawing has been analyzed considering both effects together.

• 조명전기설비학회논문지
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• 제24권9호
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• pp.1-7
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• 2010

Ceramic metal halide lamps have been widely used due to long lifetime, high luminous efficiency and good colour rendering. 35[W] ceramic metal halide lamps has very different characteristics between ignition state and steady state. The developed electronic ballast is satisfied to both ignition state and steady state characteristics by using a micro-controller. The proposed electronic ballast is consists of EMI filter, Full-wave rectifier, Active PFC, DBI(Dual Buck Inverter), Igniter and control circuit. It enables to supply both low-frequency rectangular wave voltage and current to the lamp by using DBI(Dual Bcuk Inverter) structure.

• 전기학회논문지
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• 제57권12호
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• pp.2238-2243
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• 2008

The use of arc tubes made of ceramic material further enhanced some of the metal halide lamp's properties. These properties translate into higher efficacy with better color rendering, stable color through lamp long life. Recently, due to an increase in the application of the ceramic metal-halide lamp, the study for the property etc. according to Ballast's driving scheme and the study for arc tube material, optimization of gas and so on are being proceeded to improve the property of the lamp. Especially, to control ceramic metal-halide lamp, the vigorous study and practical use with respect to Electronic Ballast, which has been improved in the disadvantages of the conventional Magnetic Ballast are made. In this paper, Electrical, optical and thermal characteristics are analyzed by comparing magnetic ballast with electronic ballast.

• 조명전기설비학회논문지
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• 제24권12호
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• pp.25-32
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• 2010

Compared to general lighting method, the lighting system that uses optic fiber can provide only the visible light of good quality to subject by eliminating ultraviolet ray and infrared ray. Thanks to this merit, it is possible to prevent the hard phenomenon of subject caused by ultraviolet ray and infrared ray and to provide the agreeable light environment. This study developed indoors illumination system of high color rendering on the basis of plastic optic fiber with excellent optical property and processing to substitute halogen lamp which has been used for excellent color rendering in spite of low efficiency and short life. Producing pilot product of the designed illumination system and evaluating the property of electric and optical property, ultraviolet ray radiation quantity and temperature property, this study verified the excellence of suggested lighting system of plastic optic fiber.

• 조명전기설비학회논문지
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• 제16권1호
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• pp.20-26
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• 2002

고압방전램프에는 고압수은램프, 고압나트륨램프와 메탈핼라이프램프가 있다. 메탈핼라이드램프는 가장 효율 좋을 램프들 중 하나이며 고효율, 고연색성과 집광능력이 좋다. 이 연구의 목적은 AC 100∼277의 프리볼트입력용 전자식안정기를 개발하여 메탈핼라이드(MH70W)를 점등시키는 것이다. 개발된 전자식안정기는 프리볼트입력용컨버터, 플라이백컨버터와 하프브리지인버터, 이그나이터와 보호기 그리고 제어기로 구성되어 있다. 실험 결과 개발된 전자식안정기는 프리볼트입력(AC 100∼277V)에 따라 메탈핼라이드램프(MH70W)가 매우 잘 점등되었다.

• Journal of Electrical Engineering and Technology
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• 제6권1호
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• pp.123-127
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• 2011

To clarify the relations of optical properties to the main factors responsible for the loss and damage of luminous efficacy, a 20 min turn-on/turn-off test for 2,000 h for a ceramic metal halide lamp is conducted. The corrosion rates of the arc tube wall and electrode are estimated based on thermal stress. Wall blackening is attributed to the tungsten being transported from the hot electrode tips to the relatively cold arc tube wall. Furthermore, the grain boundaries of the arc tube are changed by the degradation. Distortion of the electrode is observed, and the ignition and the driving voltage of the load both increase. Finally, the color rendering index and the color coordinates are changed after the degradation. The luminous flux and the intensity of the luminous distribution are decreased significantly.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 Techno-Fair 및 추계학술대회 논문집 전기물성,응용부문
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• pp.159-160
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• 2008

In recent, ceramic metal halide lamps that use the ceramic in arc tube material have the advantage of high rendering index, high efficacy, long life. According to increase applications, the research continue to improve various factor that is arc tube material, optimization of gas and metal halide. In oder to improve system characteristics of CMH Lamp with ceramic arc tube, when operating CMH lamp with magnetic and electronics ballast, we compared with electrical, optical characteristics in this paper.