• Journal of Korean Ophthalmic Optics Society
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• v.20 no.3
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• pp.293-300
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• 2015

Purpose: To evaluate blue light hazards of LED lightings in an optical store with blue light radiance used as the quantitative indicators of photobiological hazard. Methods: The spectral radiance of each LED lightings was measured, and blue-light radiance and the corresponding maximum exposure time were calculated. Then each LED lighting was classified according to the risk group from IEC 62471 standard. Results: The yellow LED lightings used in showcases and white LED lightings used on ceilings and logo were classified into risk group RG0. But the white LED lightings used on showcases were classified into risk group RG1. The blue light radiances of white LED lightings used in showcases are dozens of times larger than that of fluorescent lamp. Conclusions: Using the value of the blue light radiance could quantitatively express the blue light hazard to various lightings. It was confirmed that white LED lightings for the showcases had high blue light hazards because of their high luminance and color temperature. Therefore, when replacing lightings in optical shop it is necessary to select the appropriate brightness and color temperature for eye health in the long term.

• KIEAE Journal
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• v.15 no.2
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• pp.117-122
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• 2015

Purpose: Generally, 30% of the total energy consumption in office building is used for artificial indoor lightings, and almost 75-85% of electric power in fluorescent and Light-Emitting Diode (LED) lightings can be dissipated as a form of heat into indoor environment. The heat generated by indoor lightings can cause the increase of cooling load in office buildings. Thus, it its important to consider indoor lightings as a heat and light source, simultaneously. Method: In this study, we installed two kinds of indoor lightings including fluorescent and LED lightings and measured surface temperature of both indoor lightings. In addition, we obtained ambient temperature of indoor space and finally calculated total heat dissipated from plenum area and surface of lightings. Result: Total indoor heat gain was 87.17Wh and 201.36Wh in cases of six 40W-LED lightings and 64W-fluorescent lightings, respectively.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2009.05a
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• pp.141-144
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• 2009

LED Lightings market remains highly fragmented, encompassing many niche applications. Architectural lighting is the largest and many applications are for colored (R, G, B) light. Hundreds of companies worldwide are participating at the luminaire or fixture level. Standard setting is on a fast track. The larger LED lightings market scale, the more important standardization of performance evaluation techniques to clearly prescribe the product specification.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2011.06a
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• pp.1017-1018
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• 2011

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2012.05a
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• pp.547-548
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• 2012

• Science of Emotion and Sensibility
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• v.15 no.3
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• pp.381-388
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• 2012

The purpose of this study is to check if LED lighting can be used as general lighting and examine the color rendering property of full color RGB LED lighting. CRI is one of the important properties of evaluating lighting. However the present CRI does not fully evaluate LED lightings. Firstly, the performance of a simple task was compared other than comparing CRI values for different lighting. For experimental preparation three types of lightings were used; standard D65 fluorescent tube, general household fluorescent tube, and RGB LED lighting. All three lightings show high error for Purple-Red. All three lightings show similar error for all hues and prove that color discrimination is not affected by the lighting. This proves that LED could be used as general lighting. Secondly, problems of the conventional CIE CRI method are considered and new models are suggested for the new lighting source. Each of the models was evaluated with visual experiment results obtained by the white light matching experiment. The suggested model is based on the CIE CRI method but replaces the color space model by CIELAB, color difference model by CIEDE2000, and chromatic adaptation model by CAT02.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.3
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• pp.674-679
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• 2011

In this paper, we experimented and analyzed about electric fire risk assessment methods of LED lightings for outdoor. LED lighting is composed of AC power lines, AC/DC converter, DC power lines and LED lamps. There are some risk factors of electric fire in LED lighting such as short circuit between power lines or power line and ground, dielectric breakdown, leakage current, abnormal voltage inflow, poor contacts(connections), etc. As a result of this study, insulation coverings of wire was ignited due to dielectric breakdown between power lines and molten marks were formed in copper conductor. LED lighting was blown out while short circuit, beside that, electrical disorder did not occur. When abnormal voltage was inflowed, electronic components such as varistor, condenser were damaged. Partial heating was produced and insulation was melted and carbonized by arc and heating while poor contacts were happened. We expect that the results of this study would be helpful for electrical safety of LED lightings for outdoor.

• Congress of the korean instutite of fire investigation
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• 2011.04a
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• pp.77-97
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• 2011

In this paper, we studied risk assessments of electrical fire and shock of LED lightings for outdoor. We examined national regulations about the LED lighting for outdoor and analyzed the appearances and compositions of LED lightings. And, We experimented about water proof, line to line fault, line to line breakdowm, overvoltage, line to line leakage in overhead line or water of LED lighting. From experimental results, we know that there are risks of electrical fire and shock by abnormal conditions at the LED lighting. Therefore, the uses of protective devices and insulated type of converter are required for the electrical safety. We expect that the results of this study would be helpful for the improvement of regulations and standards for electrical safety and for the investigations of electrical accidents of LED lightings.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.10
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• pp.25-33
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• 2015

LED lightings combined with IT technology can provide variable illumination environments that can be controlled by users according to their emotional need and preferences. This is one of the most beneficial functions compared with conventional lightings offering only fixed color and brightness. There is however lack of analysis data for creating practical lighting solutions satisfying user preferences in a wide range of applications from residential to commercial places. To materialize the technical advantages of user-controllable LED lightings, more observation data are required in various situations. Therefore, dissimilar emotional needs are determined in the present study for compartmental office spaces (staff lounge room, meeting room and desk job place) through subjective experiments by 45 observers. The optimum lighting conditions (CCT and illuminance) are finally obtained using Response Surface Method and relevant prediction functions are also deduced. The final outcome can be applied for making user-preferred office illumination products.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.2
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• pp.62-68
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• 2015

Recently, LED is being used as various applications such as home lightings, work lightings and so on. EMI noise generated from LED driver have become a problem according to increase the use of LED. In this paper, Active EMI filter composed active and passive components is discribed as a method of solving a problem of EMI. The proposed filter is applied to the 160W LED load to verify performance experimentally. To compare the performance, We did an experiment using the proposed filter and the passive filter on the same 160W LED load and Driver System. As a result, The proposed Active EMI filter attenuated Conduction EMI noise better than any existing passive filter.