• KIEAE Journal
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• v.3 no.1
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• pp.21-29
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• 2003

Scale model measurements should be conducted under an actual sky or in a simulated sky where conditions can be held constant. A number of successful attempts have been made to develop artificial sky domes with man-made sun emulators. With reference to formerly-developed examples, sky simulator facility has recently been activated in oder to provide desirable sky conditions for teaching and studies. The structure is a 6m-diameter dome and promises to set various condition for energy related and lighting research activities. The sky dome is also equipped a heliodon, the tilt table, to facilitate additive direct sun impact under clear skies. Shading studies, using scale models with the heliodon, reveal how a building's design blocks or permits light's passage to the interior; solar access studies, and tests of the reflection and transmittance characteristics of new daylighting technologies. The design and construction specification and the initial operating experience with a building configuration are reported.

• KIEAE Journal
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• v.17 no.3
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• pp.35-44
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• 2017

Purpose: This study questioned the efficiency of daylight factor as a daylight adequacy and investigated a method of how to complement its weakness by considering a direct sunlight component under a clear sky condition. Method: The Snowdon visitor centre cafe was chosen as a case study building and various techniques such as BRE formula, BRE sky protractor, Pilkington dot diagram and mock-upscale model under the artificial sky simulator were used to analyse and compare daylight factor values. An analysis of direct sunlight component under the clear sky condition was carried out by Climate Consultant 5.5, sun path diagram, and the artificial sky simulator. Result: The result of daylight factor analysis differed by the adopted techniques and it was also contradictory to the results on a direct sunlight penetration. The result not only showed the limitation of daylight factor as a metric but also suggested an improvement by combining it with direct sunlight analysis. The techniques used in this study had a merit of being applied in the early design stage and thus be beneficial to many design professions in order for early daylight performance analysis.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.34 no.4
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• pp.83-91
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• 2018

Artificial lighting contributes greatly to developing civilizations. It allows daytime activities to continue throughout the dark hours of the day and thus increasing work productivity as well as allowing people to enjoy nighttime activities. In addition, artificial lighting is used to beautify landscapes, architectural monuments, and thus highlighting the social-economic development of a given place. However, excessive and improper usage of artificial lighting can lead to light pollution. Light pollution is a serious issue that is detrimental to human health. It has been linked to a number of health conditions including sleep disorder, visual discomfort as well as cancer. The effects of light pollution extend throughout the entire ecosystem, affecting both plants and animals. Furthermore, sky-glow from light pollution hinders astronomical observation. The current paper presents a study conducted on lit environment of a nightscape. The quality of the sky was measured in 144 spots using Sky Quality Meter (SQM) devices. The measured spots were chosen on the basis of land use as well as distance from the Halla Mountain.

• KIEAE Journal
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• v.5 no.4
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• pp.51-57
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• 2005

For the evaluating daylighting performance, field measurement, scale model test and a set of computer tools can be applied. For the scale model measurements, the sky simulator is a vital facility to represent the desired sky conditions consistently. Recently K university has developed a large size sky simulator, 6m-diameter and 3.7m-height, that is suitable for the international standard. To verify the reliability of the sky simulator, the luminance distribution on the inner sky surface was measured and compared with the CIE standard overcast sky model. It is found that the sky simulator can be reproduced the CIE standard overcast sky condition with 4.3% as mean difference. K university sky simulator is fully validated for usability and accuracy for daylighting researches.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.4
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• pp.1-10
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• 2007

KH University has developed a large sky simulator which is its scale suits international standard. To verify the reliability of the sky simulator, the luminance of 36 points on the inner sky surface was measured and compared with the CIE standard overcast sky model. It was found that the sky simulator can reproduce the CIE standard overcast sky condition with 1.8[%] of mean difference. To identify the differences of daylighting performance, scale model measurements were taken under a real sky and in a sky simulator. Under overcast sky conditions, two kinds of scale model experiments were conducted by using the photometric sensor Li-cor. Firstly, a 1/20 scale model of a side-lit office room 4.9[m] wide, 7.2[m] long, and 2.6[m] high was created. Five measurement points were set at 1.2[m], 2.4[m], 3.6[m], 4.8[m], and 6.0[m] from the window. The mean difference of the light factor between the sky simulator and real sky was 7.1[%]. Secondly, a 1/30 scale model of a top-lit atrium 15[m] wide, 15[m] long, and 15[m] high was created. The measurement point was set at center of the room and the well indexes of the model were set in 5 types. The mean difference of the light factor between the sky simulator and real sky was 1.7[%]. This proved that the sky simulator is fully accurate and usable for daylighting research.

• Journal of Korean Association for Spatial Structures
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• v.8 no.4
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• pp.91-100
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• 2008

In this study, the vibration control performance of high-rise building structures connected by a sky-bridge has been investigated. The philosophy of vibration control using sky-bridges is to allow structures with different dynamic characteristics to exert control forces upon one another through sky-bridges to reduce the overall responses of the system. The the high-rise building structure connected by sky-bridge with 49 and 42 stories was used in this study to investigate the displacement, acceleration, reaction of bearings and stress of sky-bridge by analytical methods. To this end, historical earthquakes, an artificial earthquake and wind force time histories obtained from wind tunnel tests were used. Based on the analytial results, the use of sky-bridge can be effective in reducing the structural responses of high-rise buildings against wind and seismic loads.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2005.11a
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• pp.67-72
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• 2005

자연채광 성능평가의 연구 방법으로는 현장측정, 축소모형실험, 수학적 알고리즘에 기초한 컴퓨터 시뮬레이션 등이 있다. 현장측정과 축소모형실험은 비교적 높은 신뢰도를 얻을 수 있는 방법이지만, 변화가 많은 자연광의 특성으로 인해 객관성 있는 측정결과를 얻는 것에 제한적이었다. 인공천공돔(Sky Simulator, Artificial Sky Dome)은 축소모형 실험 시 이러한 문제점의 보완을 위한 평가 시설이며 천공의 상태를 일관성 있게 조정함으로써 보다 객관성 있는 자연채광연구를 실시할 수 있다. 이에 따라 K대학에서는 직경 6[m], 높이 3.7[m]의 인공천공돔을 자체 개발 제작하여 연구에 사용하고 있다. 본 연구에서는 인공천공돔 기존사례에 대한 고찰과 이를 바탕으로 제작된 K대학 인공천공돔의 개요를 소개하고 기본적인 물리량 측정을 통해 인공천공돔의 신뢰성을 검증하고 유용성을 제시하였다.

• Proceedings of the KIEE Conference
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• 1988.11a
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• pp.210-213
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• 1988

A new and accurate expression to derive a window area is presented with a sequence for daylighting design using Daylight Factor Method process not in its classical point--by-point method but in lumen method as in artificial lighting design process to consider daylight in the early stage of a building design process. Accepting CIE Overcast Sky as the worst state with the lowest sky luminance, a user of a room can have more available daylight in his or her room. In the design process uniformity is checked to ensure reasonably even daylighting by comparing the depth of the room with the computed limiting depth. After these steps the shape and position of window is altered, of which the Sky Component of Daylight Factor under an Overcast Sky, SCo, is investigated and computed in Composite Simpson Multiple Integral so that a building designer or an analyst can choose the best shape and location that satisfies his/her taste and purpose of the room.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.10 no.3
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• pp.14-24
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• 2007

The purpose of this study was to investigate how the landscape characteristics and the physical factors of landscape would affect the preference for the Gapcheon in Daejeon Metropolitan City. The Gapcheon was divided in three sections of the outskirts, Expopark areas, and residential complexes. After selecting seven landscape points where the sections could be expressed best, photographs were taken both in the upstream and downstream direction. The questionnaire used to evaluate the river's landscape included 20 items of adverbs that described the form of the river and one item to rate the overall preference. By analyzing the 14 pictures taken, the occupancy rates of the landscape elements in terms of the sky, river, vegetation of the river, mountain, and artificial structures. Image factor analysis was conducted for each of the sections in order to analyze the landscape characteristics of the Gapcheon, and then regression analysis was conducted in order to analyze the relationships among the physical factors influencing the preference of the landscapes. The results were as follows : Factors that compose the visual characters of urban river were classified be the aesthetic factor, the emotional factor and the situation factor. These 3 factors showed a 65.8% total variance. The river landscape with the biggest preference was the one from the Daedeok Grand Bridge as the occupancy area of the mountain, sky, and river was large and distributed evenly and the vegetation of the river was in a good harmony with the surroundings. After carrying out regression analysis to examine the relationships between the visual preference of Gapcheon and the physical factors of landscape(the sky, river, vegetation of the river, mountain, and artificial structure), the following regressions model was made : PRE=5.906+0.017(river)-0.053(artificial structure)-0.060(vegetation of the river) (R-square=0.48).

• The Journal of Korean Association of Computer Education
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• v.6 no.3
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• pp.47-56
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• 2003

We describe a new method for removing non-linear phased array antenna aberration called "squint" problem. To develop a compensation scheme. theoretical antenna and artificial neural networks were used. The purpose of using the artificial neural networks is to develop an antenna system model that represents the steering function of an actual array. The artificial neural networks are also used to implement an inverse model which when concatenated with the antenna or antenna model will correct the "squint" problem. Combining the actual steering function and the inverse model contained in the artificial neural network, alters the steering command to the antenna so that the antenna will point to the desired position instead of squinting. The use of an artificial neural network provides a method of producing a non-linear system that can correct antenna performance. This paper demonstrates the feasibility of generating an inverse steering algorithm with artificial neural networks.