• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.17 no.6
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• pp.185-201
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• 2018

Road lighting is highly preferred as the major nighttime road safety countermeasures. When it comes to the pole-type road lighting, as it's installed at a certain height from the road surface, the driver is dazzled by the light source, interrupting the driver's visibility and furthermore, the light leaks to the area outside the road boundary, worsening the energy efficiency as well as generating the light pollution to the surrounding environment including the animals and plants. The study developed the low-level lighting systems, so it is possible to prevent the lights from being strayed, so there is no any side effects in terms of the sleep deprivation. The study compared the performance as the lightings between low-level lightings and conventional pole based lighting systems. As the results, the low-level lighting systems showed the higher performance in terms of average surface luminance, uniformity, glare compared to the conventional lighting systems.

• Journal of the Korean Institute of Landscape Architecture
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• v.38 no.5_2
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• pp.186-193
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• 2010

The purpose of this study was to survey the citizens for their satisfaction with the outdoor landscape lighting in Gyeongju Historic Areas registered as UNESCO World Cultural Heritage in November 2000 and thereupon, provide for some basic data useful to the design of the outdoor landscape lighting for the cultural properties. As a result of examining the conditions of the outdoor landscape lighting in Wolseong Zone of Anapji, Banwolseong, Dongbu Sajeokji, Cheomseongdae and Gyerim, there were found 391 lighting fixtures of 12 types in Anapji, 138 lightings of 4 types in Banwolseong, 38 lightings of 6 types in Cheomseongdae, 28 lightings of 3 types in Dongbu Sajeokji and 54 lightings of 5 types in Gyerim. As a result of analyzing citizens' satisfaction with the outdoor landscape lighting, it was found that citizens were satisfied more or less with the nightscape image changed by the outdoor landscape lighting; their satisfaction scored 3.836 on average for Anapji on a 5-point Likert type scale, 3.516 for Banwolseong, 3.446 for Dongbu Sajeokji, 3.650 for Cheomseongdae and 3.479 for Gyerim. However, citizens' satisfaction with the originality of the nightscape was generally low: 3.055 for Anapji, 2.914 for Cheomseongdae, 2.877 for Banwolseong, 2.847 for Gyerim and 2.665 for Dongbu Sajeokji. On the other hand, since most of the lighting fixtures were installed as inserted lights or floodlights, the color tones of light source were relatively highly distinctive, but the peripheral spaces around the cultural properties were rather dark, which means that citizens were feeling inconvenient more or less for using the amenities such as bench or waste box. All in all, their satisfaction with the outdoor landscape at the sample zone at night scored 2.981, lower than the normal level.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.2
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• pp.8-18
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• 2015

This paper proposes a dimming method and a hybrid LED driving circuit suitable for the ultra high definition (UHD) broadcasting. There are major two problems during the dimming control for traditional LED broadcast lightings; one is a flicker that occurred when camera filming to these lightings, and the other is that linear control is impossible for LED luminous intensity under 10% due to LED electrical characteristics. The proposed dimming method and the driving circuit are designed to solve two problems simultaneously. For high level dimming control region from 10 to 100%, the analog control method was applied to the switching regulator constructed by MOSFET operated in the saturation region. For low level dimming control region under 10%, the fast PWM control method with the linear regulator constructed by MOSFET in the ohmic region was used. We verified experimentally that the dimming method is able to control the luminous intensity linearly from 1 to 100% and the flicker disappears on images taken by the charge coupled device (CCD) and the complementary metal oxide semiconductor (CMOS) cameras. Therefore, the proposed method is suitable for the UHD broadcasting.