• KIEAE Journal
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• 제13권2호
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• pp.61-66
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• 2013

This study is to eliminate the need for conventional high density plant factory's artificial light source such as LED to reduce the initial investment of the light source installation as well as the operation cost. Use of solar light could enhance the quality of the vegetables similar to those grown in the natural environment. Provision of solar light into the multilayer vegetable cultivation facilities and collecting maximum and sustainable sunlight without too much loss by tracing solar path and properly distributing it through careful control during daytime are crucial for realizing the investigated rooftop light shelf system for multi-layered vegetable cultivation. In this study, we developed an innovative way of effectively allocating sunlight inside even to otherwise shaded zone of a multi-layer vegetable cultivation facility. To prove the effectiveness of the system's sunlight collection and distribution capability, both simulation and experiment in Daejeon are performed and the outcome is analyzed.

• KIEAE Journal
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• 제7권5호
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• pp.41-46
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• 2007

The lightshelf system, a horizontal shading and light redirect device, should improve the visual environment by optimal light distributions and intense illumination levels of a interior. This study aims to evaluate the daylighting performance of window integrated lightshelf systems by computer simulations. For the study, the standard office plan is analyzed through the field surveys. And then, the various lightshelf types attached window systems are picked out from existed research results. The max, minimum and average illuminance levels of interiors and illuminance distributions are evaluated by Lightsacpe 3.2 programs based on the installing height, shape type and moving angle of lightshelfs. As results, it is suggested that the optimum lightshelf shapes are the height 1.8m and the width 600mm. Also, in mixed lightshelf, the outside width 600mm, inside width 400 are efficient on indoor daylighting performance.

• KIEAE Journal
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• 제6권2호
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• pp.3-10
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• 2006

This study assessed the visual performance of luminous environment by the lightshelf. The subject survey method was used and results are presented and analyzed. The lightshelf daylighting system was developed by LAEL at KH University and was applied on the window of a mock-up office. The questionnaire for assessing visual performance contains 9 questions with 7 grade bipolar scales. The experiment was conducted during the bright part of the day from noon to one thirty on June 7, 2006. The questionnaire for assessing visual performance contains 9 questions with 7 grade bipolar scales. During the experiment was carrying out, the work plane illuminance and luminous distribution at surrounding the windows was measured. The semantic differential rating data of experiment were analyzed by t-test and factor analysis using SPSS 12.0 statistics package. The visual performance of the lightshelf was more positive. The factors affecting the visual performance are task performance and visual comfort. The subjects were more comfortable in a room installed with lightshelves on both the task performance and the visual comfort aspect. Therefore, the application of sloped lightshelf daylighting system improves visual performance of luminous environment.

• 한국정보과학회논문지:시스템및이론
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• 제36권3호
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• pp.210-216
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• 2009

CPU기반의 볼륨 광선 투사법을 위하여 빈 공간을 도약하는 많은 방법들이 소개되었다. 하지만 광선의 샘플점이 투명한 공간과 비투명한 공간 사이에 있는 반투명-셀에 놓일 경우 기존의 방법들은 투명도 값을 매번 계산해야 하는 문제점이 있다. 이 문제를 해결하기 위하여 기존 마칭큐브를 이용하는 방법이 제안되었다. 광선이 반투명-셀에 도착하면 마칭큐브 방법을 이용하여 생성된 삼각형들을 둘러싸고 있는 육면체를 구하고, 현재 샘플점이 육면체 내/외부에 있는지 계산한다. 샘플점이 육면체 외부에 위치하면 투명하다고 판단되어 재샘플링 연산없이 다음 샘플점으로 이동한다. 하지만 기존의 마칭큐브 테이블 구조를 그대로 이용하면 인접한 복셀의 테이블 값을 여러 번 참조해야 하므로 비효율적이다. 본 논문에서는 볼륨 광선 투사법에 적합한 마칭큐브 테이블을 제안함으로써 렌더링 속도를 높인다.

• KIEAE Journal
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• 제13권1호
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• pp.133-140
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• 2013

The purpose of this study was to test the effectiveness of the light-shelf system combined with IT to save lighting energy in resident space. According to the multiple variables that affected intensity of illumination, various experiments were designed and conducted. The main findings of this study were following: (1)the optimal level of light-shelf system was formulated which met the appropriate range of intensity of illumination in living-room; (2)although the mixed light-shelf system indicated a high performance, it could often provide discomforts to residents according to the degree of exposure; (3)artificial lights using light-shelf system combined with IT showed a higher effectiveness than those using fixed light-shelf system displayed. This study provided initial information of light-shelf system formative processes that could contribute to the lighting energy diminution. Future studies should focus more on multiple approaches regarding different types of resident space planning.

• 조명전기설비학회논문지
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• 제19권2호
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• pp.13-22
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• 2005

채광과 직사광 제어라는 자연조명의 상반된 목적을 동시에 충족시키기 위하여 본 연구에서 기존의 유리 창호를 용도와 기능에 따라 채광창과 조망창의 두 부분으로 분리한 이중분할창호시스템이 설계되었다. 채광량을 극대화하기 위하여 고창부의 채광창은 투명유리를 사용하며 조망창은 제어를 위한 다양한 기능성 유리를 적용하였다. 부가적으로 물리적 광제어 및 조절장치인 광선반, 수평 및 수직형 블라인드가 내장된 일체형 이중분할창호를 포함한 포괄적인 광제어 기법의 양적$\cdot$질적 조명효과를 통합적으로 평가하여, 제안된 창호시스템의 적용성을 평가하였다. 조망창과 채광고창의 경계부에 수평형 광선반을 설치하면 일차적인 직사광 유입으로 인하여 극심하게 높은 조도를 나타내는 창면 관접부의 조도를 완화시키는 차폐효과와 아울러 광선반의 반사 능력으로 인하여 채광성능면에서 불리한 실내측 후면부의 조도를 증가시키는데 현격한 효과를 2차적으로 기대할 수 있다. 실내바닥 수평면의 평균조도는 차광기능에 의하여 균제도가 2배 이상 향상되며 수평 슬릿의 반사에 의하여 $16(\%)$ 이상 증가하는 효과가 있으며 태양고도가 낮고 방위각이 정남향이 아닌 경우 수직 차광재를 사용하면 광제어 기능으로 인한 균제도의 향상과 $10(\%)$이상의 후면부 조도의 증가 및 조망이 확보되는 상대적인 장점이 있다.

• KIEAE Journal
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• 제12권6호
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• pp.129-134
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• 2012

The lightshelf system, a daylighting device, has been applied to improve the visual environment by optimal light distributions and intense illumination levels of a interior. Also, The photovoltaic is one of the most important sustainable technologies appliable to architectures. This study aims to evaluate the performance of photovoltaic integrated lightshelf system. For the study, the 1/5 scaled office models were made and the field tests were experimented under clear sky conditions. The power ratio has been analyzed to evaluate the performance of photovoltaic integrated lightshelf system. As results, the power performance was high on photovoltaic lightshelf installation angle $0^{\circ}$. And the performance was reduced on 23(%) by installation angle $15^{\circ}$ and 63(%) by installation angle $30^{\circ}$.

• 설비공학논문집
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• 제26권6호
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• pp.275-286
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• 2014

Light shelf is an efficient system that reduces the energy consumption by bringing the natural light down to the deep spaces inside of a building. However, the existing light shelves have limits in reducing energy usage, because the direction of the light flow is determined by the external environment such as the altitude of the sun and the azimuth. This current study presents a system that increases the efficiency of the light shelf by applying the Location-Awareness technology, in which the efficiency was verified through the performance evaluation. According to the examination of the technology for the Location-Awareness within residential space, 'Zigbee' type appears to be the most appropriate. The Location-Awareness technology operates the light shelf based on both the angle control axis and the light shelf angle control axis through the modularization of the reflector surface which is less affected by the external environment. The results of the performance evaluation showed that the movable light shelf that employs the Location-Awareness technology can reduce the energy consumption for lighting by 98.3% compared to the fixed light shelf and by 97.3% compared to the movable light shelf without Location-Awareness.

• KIEAE Journal
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• 제2권3호
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• pp.17-24
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• 2002

For sustainable building design, using day lighting is considered a variable technique to save energy and create comfort indoor environments. Specially, the lightself as a integrated daylighting system is one of the most important techniques due to it's durability, availability and lighting performance. This paper aims to analyze the development and architectural application of a lightself system to buildings as a integrated day lighting system. For the study, advanced lightself systems developed in abroad such as "Integrated Enveloped and Lighting System", "Anidolic Daylighting System" and etc. are analyzed. Also, the architectural examples are investigated. As results, the new technologies such as optically treated reflective and sun-tracking are adopted to improve daylight performance. And, lots of environmentally friendly buildings are installed on integrated lightself system.

• 한국태양에너지학회 논문집
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• 제31권4호
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• pp.136-141
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• 2011

The lightshelf system reduces intense illumination levels of indoor from direct sun light and reflect to lead diffused light into indoor deeply. This study aims to design acurved-lightshelf by a ray tracing method and evaluate the daylighting performance of window integrated with the curved-lightshelf by computer simulations. For this purpose, evaluation test model was designed for the experiments to validate the simulation model, and the curved-lightshelf was designed by the ray tracing method using Ecotect. After the office model was designed using 3D simulation, the average indoor illuminance, luminance and distribution of illuminance were evaluated by simulation which has a algorithm of Radiosity and Ray-Tracing method under four different cases(case1;no lightshelf, case2; Flat board, case3; tilted at $30^{\circ}$ angle, case4; the curved-lightshelf). As results, it turns out that case1 showed higher average illuminance and case4 was more uniformly distributed than case2 and case3, In addition average luminance of case1 was also lower. indicating that the curved-lightshelf would reduce the possibility of the glare, while maintaining the sufficient daylight level.