• 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.

• Journal of Korean Living Environment System
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• v.20 no.2
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• pp.233-237
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• 2013

Daylighting affects the luminous environment and provides comfortable environment to the occupants. However, excessive daylighting might have negative influences on the visual comfort. Skylight, light intensity and distribution, and insolation could cause glare effects on the occupants. This study analyzed the effect of fenestration on the interior glare effects, and verified luminous environment adjustability through mock up test of conventional fenestration and 'Convergence Window System' by analyzation of luminance, luminance contrast, and glare effect. Consequently, room installed Convergence Window System was improved luminance contrast and PGSV Level.

• 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.

• 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.

• 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.

• Journal of the Korean Association of Geographic Information Studies
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• v.13 no.4
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• pp.91-100
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• 2010

Existing traffic safety studies have focused on identifying the relationship among roadway crashes, highway design and incremental weather condition such as rainy/ice weather. However, it is hard to find researches that studied the effect of sun glare on traffic safety although there are abundant evidences demonstrating that fatal traffic crashes are attributed to the sun glare. Affecting drivers'vision particularly during the morning or the evening time when the sun positions close to the horizon, sun glare directly deteriorate drivers'judgmental capability. In this paper, we numerically analyze the effect of sun glare on the drivers'vision in time and space domains. Applied to the roadways around St Louis area in the United States, the GIS based simulation analysis identifies the time of day in a year and the segments of highways that are potentially influenced by the sun glare. This study evidentially confirms the fact that roadway bounded for West and East directions have longer time influenced by sun glare particularly during Spring and Fall season than other roadways. The computational result provides risky time periods of day at intersections or pedestrian crossings where the sun glare potentially endangers traffic safety, which be utilized to reduce the crashes due to the sun glare.

• Journal of the Korean Society of Safety
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• v.36 no.2
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• pp.26-31
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• 2021

Buildings with glass curtain walls have become popular due to their appealing aesthetics and ability to let in natural light. However, light reflection from the glass surface is unavoidable in these buildings. In particular, the reflection of light from the glass envelope can create afterimage glare, a hazard to nearby drivers and pedestrians. Despite this potential danger, glare from buildings with curtain walls has not been well-studied. Hence, we analyzed the effect of light reflection on glare around a glass-enclosed skyscraper, depending on its surface reflectance. We investigated the potential hazard of glare to drivers using a commercially available software program. The results indicate that the direction of light reflection is distinctive when the incident angle of solar light increases. Moreover, this light reflection is high enough to induce an afterimage to drivers and pedestrians near the building. We found that keeping the reflectance of the building surface under 3% is required to minimize the afterimage hazard to drivers. Consequently, we recommend managing glass reflectance and installing additional traffic safety systems to reduce traffic accidents near curtain wall buildings.

• Steel and Composite Structures
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• v.47 no.3
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• pp.395-403
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• 2023

The main objective of this article is to investigate the response of different fiber metal laminates subjected to low velocity impact experimentally and numerically via finite element method (FEM). Hence, two different fiber metal laminate (FML) samples (GLARE/CARALL) are made of 7075-T6 aluminum sheets and polymeric composites reinforced by E-glass/carbon fibers. In order to study the responses to the low velocity impacts, samples are tested by drop weight machine. The projectiles are released from 1- and 1.5-meters height were the speed reaches to 4.42 and5.42 meter per second and the impact energies are measured as 6.7 and 10 Joules. In addition to experimental study, finite element simulation is done and results are compared. Finally, a detailed study on the maximum deflection, delamination and damages in laminates and geometry's effect of projectiles on the laminate response is done. Results show that maximum deflection caused by spherical projectile for GLARE samples is more apparent in comparison with the CARALL samples. Moreover, the maximum deflection of GLARE samples subjected to spherical projectile with 6.7 Joules impact energy, 127% increases in comparison with the CARALL samples in spite of different total thickness.

• Journal of Korean Ophthalmic Optics Society
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• v.21 no.1
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• pp.23-34
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• 2016

Purpose: In the present study, the effect of circle contact lenses wear on contrast sensitivity and glare sensitivity in a refractive surgery group was investigated. Methods: The contrast sensitivity and glare sensitivity were evaluated using by CGT-1000 for a non-refractive surgery group as control group(40 eyes) and a refractive surgery group(30 eyes) applied plano circle contact lenses, and pupil size was also measured. The correlation between contrast/glare sensitivity and the pupil size was analyzed. Results: In the refractive surgery group, contrast sensitivity in the range of high spatial frequency decreased with wearing circle contact lenses, and amount of decrease for the refractive surgery group was larger than for the control group. The correlation between pupil size and the change of contrast sensitivity was decreased by wearing circle contact lenses, and the correlation was lower in the refractive surgery group than the control group. Furthermore, the wear of circle contact lenses affected on glare sensitivity. In analyzing the change of glare sensitivity by pupil size, the glare was larger in the refractive surgery group than control group. Circle contact lenses in refractive surgery group were not fitted on the center of cornea. Conclusions: In the present study, it is suggested that the sufficient understanding and consideration about the decrease of contrast sensitivity and the increase of glare by wearing circle contact lenses after the refractive surgery is necessary.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.23 no.1
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• pp.64-68
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• 2014

This paper introduces the use of a crown-shaped (CR) lens to effectively diffuse the light from a light-emitting diode (LED) without any loss in the light intensity, in contrast to polymer-bulb-type diffusers. The diffusion lens was designed based on the Snell's law, which describes the physical path of a ray passing through the boundary between different media. CR lenses were fabricated by polydimethylsiloxane (PDMS) casting and UV-embossing processes, which used a pre-designed metal mold and UV-curable resin, respectively. Through experiments and optical evaluations, it was verified that the newly proposed CR lens not only decreased the vertical light strength and glare effect from an LED light source but also improved the diffusion characteristics while maintaining the quality of the LED's light intensity.