• Title, Summary, Keyword: GLARE

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Effect of Luminance Difference on Discomfort Glare from a Large Glare Source with Non-uniform Luminance (대광원의 상하부 휘도차가 불쾌글레어 평가에 미치는 영향)

  • Kim, Wonwoo;Kim, Jeong Tai
    • 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.

Evaluation of Discomfort Glare Indices in Office Lighting (사무실 조명에서의 Discomfort Glare 계산법 적용 및 평가)

  • Hur, Nam-Don;Kim, Hoon
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.16 no.6
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    • pp.13-21
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    • 2002
  • In the interior lighting, usually we refer to TAL and general lighting. The last one is that we generally adopt it in the interior lighting conditions. Here, glare is most important factor of them, especially in working place using VDT. Reference or development of estimation on glare has been studied in CIE, IESNA etc. and these of glare regulations now are applied differently in the interior lighting design or estimation on glare. But we have no glare regulation in detail, of course except G classification, which has limit of itself, so in my case it is impossible to apply in the interior lighting. On this paper, with some of main glare regulations in the world and our conditions in the interior lighting which are selected carefully, in an actual state it has been estimated So, it intended to blow which one is most suitable or what factors are considered of them, also show glare index which are appropriate to our interior lighting.

Perception of Glare Source According to the Luminance Difference on a Window Plane (창면의 상하부 휘도차에 따른 글레어 광원의 인식변화)

  • Kim, Wonwoo;Kim, Jeong Tai
    • 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.

Preliminary Experiments on Discomfort Glare and Subjective Impressions from the Window Views (창의 조망에 따른 분위기 및 시각적 쾌적성 평가에 대한 예비실험)

  • Shin, Ju Young;Yun, Geun Young;Kim, Jeong Tai
    • 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.

Subjective Evaluation of Glare for Blinking and Colors of Vertical LED Lighting (수직형 LED 조명의 색상 및 점멸에 따른 눈부심 주관평가)

  • Jung, Hyun-Ji;Kim, In-Tae;Choi, An-Seop
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.29 no.1
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    • pp.22-30
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    • 2015
  • Currently, in South Korea, 'Light Pollution Prevention Act by Artificial Lighting' has been enforced. For advertising lighting, it is limited based on only the light-emitting luminance. Luminance is a concept related to the glare. Not only the luminance of the light source, but also glare is affected depending on some situations like blinking, luminance contrast, background illuminance. This study conducted glare subjective evaluation with brightness, color, and blinking by looking at the LED lighting box. The results showed that the glare indexes were higher about 2 times in a decrease of background illuminance from 100lx to 0lx. The glare index of R, G, B light was higher than that of white light. The average glare index of the blue light was higher about 8 times compared to 2,700K. And the blink rate had little effect on the glare, but it affected the irritation. Therefore, the glare effect of light color and blinking needs to be considered for the standard of luminous environment.

Comparison of the Interior Lighting environment Considering Glare Calculations (각종 Glare 규정에 따른 실내조명상황의 비교분석)

  • Hur, Nam-Don;Han, Jong-Sung;Kim, Hoon
    • Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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    • pp.87-92
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    • 2001
  • 실내의 조명상황에서 Glare의 문제성을 지적하고, 실제로 공간내 조명기구로부터의 Glare를 평가하였다. 정해진 위치에서 공간을 바라봤을 때, 시야에 들어오는 광원들에 의한 직접 Glare를 각종 Glare 규정에 따라 평가를 하였으며, 상호 비교분석도 하였다. 특히, KS에서 조명기구에 대한 최대 휘도를 제한하는 G분류의 적합성을 상호 분석함으로써 그 결과를 살펴보고자 하였으며, 현 KS의 G분류의 개선점이나 보완점을 지적하고자 한다.

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An Experiment of Discomfort Glare from Non-uniform Glare Source (불균일한 휘도를 갖는 창면의 불쾌글레어 평가실험)

  • Shin, Ju-Young;Kim, Jeong-Tai;Kim, Won-Woo
    • 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.

An Assessment of the Disability Glare by the Road Lighting System Installed on Guardrails

  • Seok, Dae-Il;Kim, Hoon
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.24 no.3
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    • pp.1-7
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    • 2010
  • To find an appropriate illuminance range for the disability glare caused by the road lighting system installed on guardrails, the influence of the disability glare was evaluated in comparison with the road lighting system of a streetlight. To test the disability glare, an indoor laboratory was constructed and a variation of luminance contrast threshold was evaluated. As a result, when the retinal illuminance was increased and glare sources existed within the narrow visual field, the luminance contrast threshold was increased. Although the road lighting luminaire was installed as low as the height of the guardrail on the road, when out of sight, the influence of the disability glare was small in comparison with the conventional road lighting system such as a streetlight.

Assessment of The Luminance Distribution from Daylighting window by Using Image Processing Methodology (이미지 프로세싱 기법을 활용한 채광창의 휘도분포 평가)

  • Park, Jong Myung;Lim, Hong Soo;Kim, Jeong Tai;Kim, Gon
    • KIEAE Journal
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    • v.12 no.5
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    • pp.77-84
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    • 2012
  • Daylighting is the controlled admission of natural light into a space, reducing electric lighting and saving energy. By providing a direct link to the dynamic and perpetually evolving patterns of outdoor illumination, daylighting helps create a visually stimulating and comfort environment for building occupants, while reducing energy costs. Especially, however, glare is the most important factor in daylighting, which is issued by incoming direct sunlight into windows. This study analyzed the discomfort glare on a daylighting window by using Image processing methodology and found a solution to problems with glare source of occupants. There are several ways to evaluate discomfort glare such as UGR (Unified Glare Rating) of CIE, DGI (Daylight Glare Index, Hopkinson, 1972) and VCP (Visual Comfort Probability) of IES. These are used to apply to the relatively little artificial light source and they cannot cover discomfort glare from a real daylighting window. In this regarding, this paper aimed to calculate DGI index of the real daylighting window in a experimental space by using image processing methodology. The variables and outcomes are luminance distribution of non-shading window, effect of venetian blind installed on the window and locations related to position index of DGI.

Effects of Security Lighting Lamps on Discomfort Glare to Indoor Occupants

  • Lee, Yoon Jeong;Kim, Jeong Tai
    • KIEAE Journal
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    • v.15 no.4
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    • pp.21-28
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    • 2015
  • Purpose: Although security lights are used to secure pedestrian visibility and safety at nighttime, they can generate light trespass in the neighboring residential space. To prevent this, standards for acceptance limits on vertical illuminance and light pollution by the windows of residential buildings are presented. Method: This study thus representatively selected three types of lamps and, through an evaluation and analysis of the physical and subjective discomfort glare per lamp, proposed a discomfort glare index for each lamp. The evaluation and analysis according to the lamps were conducted through experiments. The variables were the security lights' lamps (NH 100W, MH 70W, LED 50W), installation angles ($0^{\circ}$, $20^{\circ}$), and installation distances (3m, 5m, 7m, 9m). Result: According to the results of the discomfort glare evaluation depending on the angles and distances of the security lights, the following minimum standards are proposed: for NH 100W, a discomfort glare index of 30 and an installation distance of 4m; for MH 70W, a discomfort glare index of 32 and an installation distance of 4m; and, for LED 50W, a discomfort glare index of 31 and an installation distance of 6m, respectively. In addition, this paper recommends the use of MH 70W, when the road width is 4m-6m, and LED 50W, when the road width is over 6m, respectively.