• Journal of the Korean Solar Energy Society
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• v.40 no.1
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• pp.35-47
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• 2020

Due to the large window area, the lighting environment of the educational space between the window and deep part of the room is not uniformly illuminated, and the phenomenon of glare is severe. For this reason, the daylight performance of DSC-BIPV windows was analyzed in order to improve the natural lighting in the educational sector. The method derives the correlation with natural lighting by measurement and simulation. Dynamic simulation confirmed that the average illuminance of the target space was higher at later than the early afternoon. The performance of natural lighting at 40% and 30% transmission of DSC has the effect of significantly reducing the amount of excess light in existing windows. Nevertheless, the actual average illuminance in all seasons corresponds to the standard illuminance of the educational facility, 300 Lux. In addition, the uniformity is also seen through the skylight illuminance ratio.

• KIEAE Journal
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• v.14 no.1
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• pp.15-22
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• 2014

Among the various building envelope elements, the glass area takes up the largest portion in the office building design. However, a large area of glass can cause problems such as excessive solar radiation, thermal comfort, and glare. Thus it is important to install the glass area to an appropriate level, and control solar radiation and inflow of daylight with blind devices. This study aims to improve the visual performance of the work plane through the automatic control of the venetian blinds. A total of eight kinds of control strategies were chosen; Case 1 does not control the blinds, Case 2 with the blind slats fixed at the angle of 0 degree, Case 3 to 6 using the existing blind control programs, and Case 7 and 8 with improved blind control. Case 3 with 90 degrees had the best energy performance, but the average indoor illuminance was 113lux, which is below the standards. Cases 4 and 5 showed higher levels of interior daylight illuminance with the average of 281lux and 403lux respectively. However, the fixed angles may have difficulties controlling excessive direct sunlight coming into the room and may cause glare. Cases 6 and 7 used sun tracking angle control and cut-off angle control, and the average interior illuminance was measured 250lux and 385lux respectively. Case 8 used the cut-off angle control in an hourly manner, satisfying the standard illuminance of 400lux with an average interior illuminance of 561lux. It was evaluated to be the best method to control direct solar radiation and to guarantee proper level of interior illumination.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2007.05a
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• pp.92-96
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• 2007

Architecture design has need of daylight prediction to utilize daylight efficiently. But it is difficult to predict the exact value of available daylight in buildings. Using various lighting simulation software is not difficulty, but we can find different results under the same conditions. The purpose of this paper is to compare simulation values from various software such as Lumen-micro 2000, Lightscape 3.2, and Relux 2006. The same space and parameters of daylight(location of space and window, date, time, and skylight condition) are considered to conduct various simulation conditions.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2005.11a
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• pp.179-184
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• 2005

The daylight responsive dimming systems, which use daylight and automatically controls the brightness of electric lighting, according to the amount of daylight coming into the indoor, as well as always maintains target illuminance, is an energy saving type system. The control slope that decide the dimming percent for dimming ballast to run this system efficiently should be decided exactly. This research ran performance assessment applying daylight responsive dimming systems to actual space, and supplemented control slope in the sky condition for the elevation of system. Also we revaluated a system by modified control slope and compiled valid propriety and alternative for the elevation system.

• KIEAE Journal
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• v.13 no.6
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• pp.77-82
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• 2013

Light environment in the school building is one of the most important elements of the plan in order to improve student's ability to learn and the healthy growth. Thus, the window plan of the school building is a great addition to improve environmental-friendly performance through the daylight control. Daylight is highly beneficial for improving the indoor environmental quality and reducing building energy consumption, daylighting applications are scarcely considered, especially during the school building design process, because of lack of previous studies on the light environment of student and complex simulation process. Therefore, daylighting process were performed using ECOTECT, which has various advantage such as easy user interface and simple simulation processes. ECOTECT simulation were performed using weather data. As a result, ECOTECT simulation are performed for daylight autonomy and useful daylight illuminance. Using this data, Window planing is to propose and effective method in the early stages of design.

• Journal of Korean Ophthalmic Optics Society
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• v.4 no.2
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• pp.33-38
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• 1999

To investigate the image-forming property of optical system having Gaussian amplitude for polychromatic source, we calculated the chromaticity variation and the illuminance distribution. Considered polychromatic sources in this paper are A light which is on incandescent-tungsten lamp, C light which is a daylight, and $D_{65}$ light which is a extend daylight to the near ultraviolet. The polychromatic sources represent the different chromaticity values at a geometrical image point. The chromaticity variation of optical system having a Gaussian amplitude is smaller than that having an uniform amplitude. The illuminance distributions for polychromatic sources present nearly the same values, and the depth of focus for optical system having a Gaussian amplitude is wider than that having an uniform amplitude. From these results, we know that the depth of focus increases and the chromaticity variation decreases, when the incident light amplitude is modulated from an uniform amplitude to a Gaussian amplitude.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.12
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• pp.20-28
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• 2008

It is prevalent to research on the energy saving systems using daylight. Daylight responsive dimming systems are to automatically control lighting output by available daylight for maintaining target illuminance on the workplane. The system application is not popular because of blocked daylight by shading systems. Automated roller shading systems automatically control shade height by sun position and sky conditions. Both daylight responsive dimming systems and automated roller shading systems should be integrated for energy savings and visual luminous environment. In this research, software are developed and integrated for control of integrated systems.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2004.05a
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• pp.195-199
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• 2004

The most important role of photosensor is to measure on exact workplan illuminance of room when daylight responsive dimming systems are used. The shape of most optimal photosensor must be able to measure exact luminous flux without changing setting position corresponding to the change of room situations. That is, shape and positioning of optimal photosensor should be corresponded to the optimal luminous flux measurement.

• Journal of the Korean Solar Energy Society
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• v.31 no.4
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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.

• KIEAE Journal
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• v.13 no.4
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• pp.3-10
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• 2013

This study aims to identify convenient surrounding of the hospital room to be improved by specifically focusing on light environment and to examine a change of inflow of the daylight in the hospital room by using blind and light shelf device as base data of preliminary research for comprehending the relationship between healing environment and natural day light. Simulation analysis on previous facilities and the installation of horizontal light shelf that derives the inflow of day light has been specifically referred by using ECOTECT2011 program. In case of C-facility that mostly adjoined to exterior spaces, it was shown to be closer to a proper uniformity factor when an angle was controlled on the light shelf with blind installed at the same time. However, it was not overall appropriate because of visual displeasure occurred from inflow of much day light. In conclusion, it is the form of flat surface such as H-facility that provides an effect after installing the device to derive day light. Especially, it was shown that interior day light environment was improved when installing blind and controlling the angle at the same time.