• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.4
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• pp.885-891
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• 2011

In this paper, we studied dc leakage current properties analysis of LED lamps of road and landscape lighting when leakage current appeared in dc power line. Generally, converter of LED lighting is divides to insulated type and non-insulated type according to components. When electric leakage happened in AC power line, earth leakage breaker(ELB) senses leakage current and interrupts electric circuit. In dc power source, We need experimental verification about dc electric leakage for electricity safety. In normal wiring conditions and in the water, in case of using insulated type of converter, dc leakage current did not occur. However, in case of using non-insulated type of converter, dc leakage current occurred and passed through into the ground. We found that there is a hazard of electric shock by dc leakage current. We expect that the results of these studies would be helpful for electrical safety of LED lamps for road and landscape lighting.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.11
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• pp.2043-2047
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• 2010

This study is to solve problems of depletion of RF bandwidth frequency, confusion possibility, security that current wireless communications system have and is to confirm possibility of applying next generation network. To solve problems of current wireless communications system, visible light communications system for power line communications using ATmega16 Microcontroller is was realized and receiver property was analyzed. PLC exclusive chip APLC-485MA, Microcontroller ATmega16, 5pi bulb type LED and high flux LED, visible light receiving sensor LLS08-A1 were used for transmitter and receiver. Performance was analyzed by designed program and an oscilloscope. It was showed average 20% improved receiver rate rather than bulb type LED in the case of high flux LED through voltage change rate on communication distance and LED type of distance between 10 to 50 cm. The blue LED showed the best performance among measured LED types with above 10% of voltage decreasing rate. But As it gradually becomes more distant, the precise date was difficult to obtain due to weak light. To overcome these sort of problems, specific values such as changing conditions and efficiency value relevant to light emitting parts and visible light receiving sensor should be calculated and continuous study and improvements should also be accomplished for the better communications condition.

• Korean Journal of Optics and Photonics
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• v.28 no.6
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• pp.295-303
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• 2017

In this paper, we have studied a method of forming a line beam using a UV LED. The existing linear-type UV LED curing optical system is composed of several cylindrical lenses, but problems such as optical system alignment, enlargement of the module, efficiency, etc. may arise in the future. As an alternative to these problems, a bar-type TIR lens having a freeform surface only in the y-axis direction is designed, to verify that it shows advantages in maximum illuminance, uniformity of illuminance, and flux efficiency.

• 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 Society of Manufacturing Technology Engineers
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• v.24 no.4
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• pp.448-454
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• 2015

In this paper, the band structural design that is typically in a line was arranged in a ring shape, so as to configure the high power LED lighting in such a way as to form a concentrated light distribution angle of less than 15 degrees. The parabolic aluminized reflector PAR38 that facilitates design using area and the area of the optical system to the same extent, applied a multiple light-source condenser lens optical system for the control of integration. The LED used here implemented a single linear light source using ans LED module with ans LED, flip-chip chip-scale package. The optical system was designed based on the energy star standard.

• Design & Manufacturing
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• v.14 no.2
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• pp.42-48
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• 2020

This study is on the injection molding analysis for the LED outdoor lighting top cover of one heat sink body type structure. Thermoplastic and thermosetting resins were applied to compare the thermal properties during the injection molding process. The thermoplastic resin is used in this study due to special characteristics that it is light, good strength and dose long not transmute quality even if pass long time. The thermosetting resin is applied to this study due to good in strength, lightweight and excellent etc, thermal conductivity. This study presented a preliminary analysis of fill time, weld line, air trap etc. for the injection molding process of LED lamp cover and body through simulation using Moldflow. As a result of the study, it was selected HTM-102 material because the thermosetting resin has excellent strength and heat conductivity.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.61 no.3
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• pp.140-148
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• 2012

Aeronautical lights, which are internationally standardized sequence of colors and placements, are aeronautic safety devices that provide visual information to pilots by continuously adjusting their light intensity to appropriate level. In this paper, we consider the development testing for in pavement LED aeronautical light system such as taxiway centerline, stop line and temporary stop line. The test results of LED sourced lights have shown a drastic improvement in power consumption levels and cost efficiency compared to their halogen sourced counterparts The LED light used only 42.7% as much power as their halogen sourced counterparts. Taking installation costs into account, LED will cost only 58% of its halogen counterparts. These results suggest that developing the LED sourced aeronautical light would result in globally competitive products thar guarantees satisfaction to their consumers, and that both cost effective and energy efficient.

• International Commerce and Information Review
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• v.9 no.4
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• pp.91-104
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• 2007

The recent stabilization of the Internet is now driving every aspect of life into an Internet presence. In the coming years, the Internet will see growth in numbers unlike the world has ever seen. The subject of this study is the Research Study on the Products Purchase Type of On-line Shopping Mall Buyer. Also, this paper is to examine the relations between customer satisfaction and intensity of repurchase intention and complaining behavior in on-line context. On-line shopping customer depths interview it led and the online afternotes trust evaluation dimension was discovered the of useful characteristic, intention characteristic, exaggerating characteristic and on-line afternotes with or without. From these results, this paper suggests effective marketing strategy to the marketer who plans to run on-line shopping mall in the near future and also to the marketer who plans to sell products through the on-line shopping mall.

• The Journal of Korea Institute of Information, Electronics, and Communication Technology
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• v.7 no.1
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• pp.20-25
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• 2014

There are several severe problems for LED device, the next generation's economy green lighting: as the temperature increases, the lamp efficiency decreases; if the temperature is over $80^{\circ}C$, the lifetime of lighting decreases; Red Shift phenomenon that wavelength of spectrum line moves toward long wavelength occurs; and optical power decreases as $T_j$ increases. Thus, Heat sink design that can minimize the heat of LED device is currently in progress. While the thermal resistance of COB Type LED was reduced by direct coupling of LED chip to the board, residential 13.5W requires Heat sink in order resolve heat issue. This study designed Heat Sink suitable for residential 13.5W COB LED down-light and selected the optimum Fin thickness through flow simulation that packaged the designed Heat Sink and 13.5W COB. And finally it analyzed and evaluated the thermal modes using contacting thermometer.

• Journal of Power Electronics
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• v.16 no.4
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• pp.1288-1297
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• 2016

This study proposes a single-stage light-emitting diode (LED) tube lamp driver with input-current shaping for T8/T10-type fluorescent lamp replacements. The proposed AC-DC LED driver integrates a dual-boost converter with coupled inductors and a half-bridge series-resonant converter with a bridge rectifier into a single-stage power conversion topology. This paper presents the operational principles and design considerations for one T8-type 18 W-rated LED tube lamp with line input voltages ranging from 100 V rms to 120 V rms. Experimental results for the prototype driver show that the highest power factor (PF = 0.988), lowest input current total harmonic distortion (THD = 7.22%), and highest circuit efficiency (η = 92.42%) are obtained at an input voltage of 120 V. Hence, the proposed driver is feasible for use in energy-efficient indoor lighting applications.