• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.1
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• pp.27-33
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• 2006

Evaluating comfort of illumination environment of building interior is recognizing the degree of glare causing discomfort. Currently, to use the experimental formula for discomfort glare studied abroad it would be not appropriate because each races feel about the degree of glare differently. Therefore, this study aim to make up prediction formula for evaluating discomfort glare reasonably from Koreans' vision and it proceeded with 4 stages as follows: First, after reviewing the existing discomfort glare evaluation formula, I selected experimental variables. Second, I made a mock-up that I can control experimental variables and conditions according to the purpose of this study. Third, 1 conducted discomfort glare evaluation experiment. Finally, compared with UGR evaluation method suggested for Westerner in prior studies. In conclusion, 1) it's proved that discomfort glare is influenced highly by a light source luminance, background luminance and location of testee and the line of vision. 2) In interior discomfort glare experiment whether the glare light source is placed within range of vision or not has more significant influence than the distance between the light source and testee. 3) I compared and analyzed with UGR, the most representative discomfort glare evaluation system and I found there is a little difference in the results. This shows discomfort glare of Koreans and Westerners are different.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.2
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• pp.1-9
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• 2009

Impact of daylighting on the visual environment can improve occupant's well-being by providing visual comfort. Also, daylighting can save energy. However, glare from window can be a direct hazard to vision and can cause serious discomfort. Selecting glare source on a window plane is very important for evaluating discomfort glare from windows. But former glare indices can not identify the range of the glare source properly. In this study, difference in glare sensation with uniform and non-uniform glare sources are evaluated to identify the range of the glare source. The glare source was assumed as $120{\times}120[cm]$ window model. The window was divided into three parts with different luminance values. The experiment was conducted under 1[m], 1.5[m], 3[m] distance from the glare source. Two results were obtained from the experiments. First, the degree of discomfort glare increased as average window luminance increased. Second, the middle and lower part of the window plane can affect evaluation of discomfort glare as well as the upper part of the window plan. These results can be used for selecting the glare source in a window with non-uniform luminance.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.1
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• pp.24-32
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• 2008

The ultimate purpose of the study is to develop a discomfort glare forecasting formula that can be practically used in Korea in order to effectively forecast discomfort glare considering the optical characteristics of the Koreans. The study was to examine the relations between discomfort glare and the variables such as luminance, background luminance, solid angle, luminous area and louver. To this end, experiments were conducted in a mock-up office that emulates the lighting environment of an ordinary office. The study was conducted by four steps as follow. First, previous studies on discomfort glare rating to define and rate discomfort glare were analyzed and modified to be applied to the experiments of this study. Second, experiment variables, variable scope, evaluation objects and evaluation points were determined after review on existing discomfort glare evaluation experimental formulas. Third, experiments were conducted in a mock-up office to be able to control variables. Finally, sensitivity of experiment variables were analyzed through examination of the relation between discomfort glare and the variables such as luminance, solid angle, louver, luminous area and subject's position. The result showed that the most influential variables on discomfort glare of an artificial light source is luminance and louver, luminous area and subject's position(solid angle) followed.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2007.05a
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• pp.11-14
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• 2007

현재, 새로운 조명광원으로서 백색 LED가 기대되고 있으며, 이를 이용하는 조명이 확대되어 실용화 될 것으로 예상된다. LED 광원을 이용하여 조명기구를 제작하고 이것을 실내조명으로 사용할 때 조명기구에 의한 글레어가 편안함을 주는지 불편함을 주는지에 대한 평가가 요구된다. 실내 조명환경에 대한 불쾌글레어를 평가하기 위해 UGR(Unified Glare Rating)을 추천하고 있다. 그러나 균일한 글레어 광원의 평균휘도를 이용하여 계산된 종래의 불쾌글레어 평가법들은 불균일한 휘도를 갖는 LED 조명기구에 대해서는 적용하기 어렵게 될 것으로 판단된다. 그래서 UGR를 이용하였을 경우, 균일한 휘도를 갖는 조명기구와 불균일한 휘도를 갖는 조명기구에 대해서 어떠한 차이가 있는지 다음의 불쾌글레어의 주관평가 실험을 수행하였다. 평균휘도가 같고 최대 휘도와 최소 휘도가 다른 조명기구(균일한 휘도를 갖는 조명기구 1종과 불균일한 휘도를 갖는 조명기구 2종)를 글레어 광원으로 사용하였다. 입체각(${\omega}$)과 위치지수(Position Index)를 고정시키고 배경휘도($L_b$)와 광원휘도($L_s$)를 임의로 변화시켰다. 주어진 환경에서 피험자로 하여금 얼마나 편안하진 또는 불편한지에 대한 느낌을 값으로 평가하도록 하였다. 우선, UGR과 주관평가 사이에 차이가 나타났으며, 이는 동 서양에 따른 문화적 및 생리적 차이에 기인한다고 생각된다. 다음으로 균일한 휘도를 갖는 조명기구보다 불균일한 휘도를 갖는 LED 조명기구가 더 높은 값을 할당 받아 LED 조명기구가 불쾌감을 더 유발시키는 것으로 나타났다. 또한 LED 소자 간격에 따른 영향은 글레어 광원의 휘도가 높아질수록 크게 나타났으며, 배경휘도에 대해서도 광원의 휘도가 높아질수록 LED 소자 간격의 차이에 의한 영향이 나타났다. 따라서 UGR식은 균일한 휘도를 갖는 조명기구에 적용하기에는 적합하지만, 불균일한 휘도를 갖는 조명기구에 적용하기에는 부적합하다고 판단된다.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.23 no.9
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• pp.6-16
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• 2009

Recently, additional pedestrian passages are installed on urban tunnels in Korea. The lighting environment of the pedestrian passages should be appropriate to pedestrians. In this study, illuminance and discomfort glare where measured for determining the actual impact that pedestrians will be influenced by the tunnel lighting condition. Illuminance and discomfort glare were measured in 'S tunnel' which is located in Dong-Jack, Seoul, at day and night. And field survey on illuminance and discomfort glare was conducted to identify subjective responses of pedestrians. From the results of measurements and the survey, it is known that the lighting environment of the pedestrian passage in the tunnel is slightly dark especially at day time. UGR values which were measured at night were also higher than that at day. The results and methods of this study will be useful data for the 'Environmental Improvement of Pedestrian passage in Tunnel' project which was begun by Seoul City at 1st December 2008.

• KIEAE Journal
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• v.7 no.5
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• pp.29-34
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• 2007

Discomfort glare from windows is an important issue in window and daylighting design. This study aims to investigate the effect of luminance difference between the lower and the upper part of a large glare source. Experiments were conducted using a luminous body divided into two parts, the upper part and the lower part. The degree of discomfort glare from the luminous body was examined. The result shows that the part with lower luminance is perceived as a glare source when the part has higher luminance then the background luminance. The degree of discomfort glare was estimated for the experimental conditions, and compared to the observations. The estimation was made using two methods: one summed the glare sensation for each section, and the other used the average luminance of the whole luminous body. The result of the comparison shows that the method using the average luminance has approximate values to the observations. Consequently, the use of the average luminance was proposed for evaluation of discomfort glare from non-uniform large glare sources.

• KIEAE Journal
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• v.7 no.4
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• pp.17-22
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• 2007

The existing discomfort glare models are based on research that was conducted exclusively with uniform luminance sources. It is impossible to apply the models to windows of non-uniform luminance. For evaluating discomfort glare from windows, the method selecting glare source on a window plane is necessary. This study was carried outto propose a practical method to choose glare source from anon-uniform window plane. In the experiment, the perception of glare source according to the luminance difference is examined using a simulated windowof non-uniform luminance. The surface of the window is divided into two or three parts, and different luminance is setting on each surface. The observers were asked to decide whether the lower part of the window can be perceived as a glare source or not. The result shows that the lower part is perceived as a glare source when the lower part has over 37% of the luminance of the upper part of the window divided into two parts, and when it has over 51% of the luminance of the upper part of the window divided into three parts. the results may be applicable to select the glare source in awindow.

• Journal of the Korean Solar Energy Society
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• v.38 no.6
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• pp.1-14
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• 2018

The shading device on the window of the building can be an passive solution to reduce the cooling load and lighting energy, as well as improving the indoor comfort. It is also an architectural element that must be considered for building energy-efficient buildings such as eco-buildings and zero-energy buildings. However, due to various building environments and various shading devices, the installation of excessive shade may lead to the risk of losing the effectiveness of windows. In this study, we propose a method for optimal automatic control of shading device and evaluate its effectiveness by energy analysis of several shading devices.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.28 no.3
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• pp.18-25
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• 2014

In this paper, tried to find out the proper luminous intensity distribution for the cabin with low-level height by analyzing the changing tendency of discomfort glare according to luminous intensity distribution of marine indoor luminaires using Unified Glare Rating(UGR). First, we analyzed UGR of the indoor luminaires in the existing cabin, and then evaluated influence on luminous intensity distributions of marine indoor luminaire. The results showed that $cos^2{\Theta}$ distribution got almost low UGR results regardless of height and UGR 16.5 in cabin height of 2m. However, Gaussian distribution with the same beam angle showed that UGR results consistently increased by getting lower height and UGR 20.7 in the same height. In conclusion, the $cos^2{\Theta}$ distribution in consideration of luminous intensity on the direction of observer's eye was appropriate for general cabin indoor luminaires because it decreased UGR in the low-level height.

• KIEAE Journal
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• v.10 no.2
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• pp.25-30
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• 2010

The daylited space can improve visual comfort and occupant's well-being. However discomfort glare from the daylight is a common problem in indoor environments and in general, the window is the main glare sources. Some formulas have been proposed for predicting glare from the daylight, however, they do not consider the effect on glare of the view through a window and some studies proved that they are inadequate in real daylight situation. This research aims to identify the relationship between view and discomfort glare considering the subjective impressions. As a preliminary experiment, this paper sets up the experimental protocol to reveal relationships between views from a window and visual perception in a controlled laboratory experiment. $1.2m{\times}1.2m$ artificial window was developed and $0.9m{\times}0.9m$ view image was placed on the window. Discomfort glare and impression evaluation was carried out under four different views and one blank view as a reference condition. The results showed that the subjects evaluated discomfort glare differently with the views even under the same luminance conditions and tended to feel less glare with distance views compared to near views.