• 조명전기설비학회논문지
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• 제25권12호
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• pp.54-59
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• 2011

LED lightings typically do not fail catastrophically during use. However, over time the light output will gradually depreciate. Even if there are same LED lighting, they are so different at all. because of dissimilar the use and environment of each LED lighting. In this paper, we make a description of reliability analysis procedures for the degradation data using collected field data. Reliability analysis procedures are consisted of estimating degradation models and failure time, verification of distribution and parameters of the distribution, and reliability measures estimation. At some point in time, the light emitted from an LED lightings depreciates to a level where it is no longer considered adequate for a specific application.

• 전기학회논문지P
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• 제63권3호
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• pp.178-182
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• 2014

This paper investigates the lighting environment of railway system which are mainly used in KTX, Saemaul and Mugunghwa. When lighting used in KTX such as fluorescent lamp and incandescence is being replaced with LED lamp, illumination load of each railroad vehicle has been compared. The comparison result shows that the reduction of power consumption is 43.34% before and after the change. Also it has been performed the economic evaluation.

• 조명전기설비학회논문지
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• 제26권6호
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• pp.73-80
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• 2012

Generally, the phase control dimmer has been widely used due to simple interface and easy handling. However, the electrical characteristics are not good for the method in which the phase control dimmer cuts the input voltage. This paper has researched about DALI(Digital Addressable Lighting Interface) controller, that is the digital lighting control method, and implemented DALI protocol satisfied with the IEC-62386 standard. In addition, the existing phase control dimmer was used as the controller of DALI and not only individual control but also group control was possible. And the performance was proved to be good by applying our theory to 30[W] LED lighting control system.

• 한국신뢰성학회지:신뢰성응용연구
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• 제18권1호
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• pp.8-19
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• 2018

Purpose: This study has developed the accelerated lifetime test method for smps for outdoor lighting LED through two factors of temperature and humidity. Methods: Acceleration condition was confirmed for each stress and model, and acceleration life test model was estimated according to acceleration condition. Results: As a result of confirming the accelerated life test model, in the case of humidity, acceleration was established only in the foreign products. Therefore, it is confirmed that the acceleration condition is insufficient. However, the estimated parameters for temperature are relatively constant. It is therefore suitable for power supply acceleration tests for outdoor lighting LEDs. Conclusion: The SMPS acceleration test for outdoor lighting LED can improve the availability of the product by developing an accelerated life test method that guarantees the reliability of the product.

• 재활복지공학회논문지
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• 제8권1호
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• pp.19-26
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• 2014

본 연구는 고령자를 대상으로 마이크로 버블과 LED 조명을 이용하여 반신욕 시 인체의 변화를 평가하였다. 피험자는 남성 고령자 6명과 여성 고령자 7명을 대상으로 마이크로 버블을 이용하는 그룹(남성 3명, 여성 4명)과 마이크로 버블을 이용하지 않는 그룹(남성 3명, 여성 3명)으로 나누었다. 실험은 LED 조명의 색상을 달리하여 4회 진행하였다. 실험 결과 교감 신경에 비하여 부교감 신경의 활성화를 보였으며(마이크로 버블을 이용 한 반신욕 : 21.41%), 빨간색 조명과 마이크로 버블을 이용한 반신욕에서 $5.93^{\circ}C$로 체열의 가장 큰 증가를 보였다. 본 결과는 마이크로 버블과 LED 조명이 반신욕 시스템에 활용될 거라 사료된다.

• 전기학회논문지
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• 제62권11호
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• pp.1550-1559
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• 2013

Light emitting diode(LED) lighting has been applied various industry fields because of its high efficiency, low power consumption, long life time, and environment friendly characteristics. Generally, LED lighting needs a driver to maintain constant current. Most popular driver is the switching converter. In the converter, there are several electrolytic capacitors. However the lifespan of the electrolytic capacitor is much shorter than LED. Therefore the lifespan of LED lighting with electrolytic capacitor is decreased. Also, LED lighting needs dimming control because of various needs and energy saving. This paper presents the dimmable single-stage PFC DCM flyback converter without electrolytic capacitor and parallel LC resonant filter for reducing 120[Hz] ripple on the output. The type 2 controller is used to maintain constant current and the analog dimming control is used. The proposed converter is verified through simulation and experimental works.

• 한국전기전자재료학회논문지
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• 제27권9호
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• pp.606-611
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• 2014

Recently, LED lighting fixtures for crosswalk become popular in order to recognize the pedestrians at crosswalk, which can enhance the safety of the pedestrian at crosswalk. However, there are several problems related to the LED lighting fixtures for crosswalk, such as a lot of energy consumption due to a constant illumination during night and glaring of pedestrians at the opposite side of crosswalk. In this study, in order to overcome these problems, we have investigated a novel LED lighting fixture for crosswalk, which has two modules with different angles ($60^{\circ}$, $120^{\circ}$). Illuminance of min and max at four-line city street crosswalk shown 50 Lux, 125 Lux, respectively. Illuminance of min and max at eight-line city street crosswalk shown 150 Lux, 200 Lux, respectively. Simulation investigation was optimized design using optical program. Prototype was verified measurement by goniometer system.

• 한국전기전자재료학회논문지
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• 제26권4호
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• pp.330-334
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• 2013

We developed a package of remote phosphor structure having blue LED chips and phosphors physically separated, and the characteristics were evaluated according to different classifications of phosphor coatings. Remote phosphor was produced by screen printing coating on glass substrate with phosphor content rated paste and heat treatment. After mounting Remote phosphor, which has been classified according to number of coatings, on top of blue LED chips, luminous flux, luminous efficacy, CCT and CRI were measured. The measurement results showed the most suitable characteristics of white LED package as a general light source when the content rate of phosphor in Remote phosphor was 80 wt.% with 3 layers of coatings and thickness over $12{\mu}m$.

• 한국실내디자인학회논문집
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• 제21권2호
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• pp.101-111
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• 2012

The purpose of this study is to draw emotional evaluation model related to LED lighting colors and suggest basic informations that enable planned directions of architectural pacade lighting to simulate beforehand in a laboratory. As experimental methods, extracted PAD emotional evaluation model and then directed a experimental model of 10 LED lighting colors, studied and analyzed survey questions. The results are as follows; First, in the case of P(Pleasure-Unpleasure), Red, Yellow, Green, Cyan, Magenta, White and Combination of $G{\leftrightarrow}B$ Colors are satisfying, vibrant and positive distribution chart has shown. Second, in the case of A(Arousal-Unarousal), Red, Yellow, Green, Cyan, Blue, White and Combinations of $R{\leftrightarrow}G$, $G{\leftrightarrow}B$, $R{\leftrightarrow}B$ Colors, it makes a little difference, they have shown useful distribution chart to induce sight in a aroused state. Third, in the case of D(Dominance-Submissiveness), Red, Cyan, Green and Combinations of $G{\leftrightarrow}B$ Colors are free, controlling and extent of effect was excellent. On the contrary, in the case of Yellow and Magenta and Combinations of $R{\leftrightarrow}B$, they are gentle and arouse the protective instinct or feminine distribution chart has shown. Fourth, it showed difference of preference that difference of select ratios of both men and women in Orange, Blue, Greenish-Yellow (preference of man) and Magenta, Combinations of $R{\leftrightarrow}B$ Colors(preference of woman).

• 한국통신학회논문지
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• 제38C권8호
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• pp.700-705
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• 2013

LED 조명을 홈네트워킹에 적용하기 위해서는 홈게이트웨이와 LED 조명 사이에서 신호를 전송하는 전력선통신이 필요하며, 양방향 전송을 위한 적절한 통신방식이 요구된다. 또한 한 개의 LED 조명을 이용해서 여러 가입자를 서비스하기 위해서는 LED의 특성에 맞는 적절한 다중화방식이 요구된다. 본 논문에서는 전력선통신과 가시광통신을 결합함으로써 빌딩 내부 넓은 범위를 서비스할 수 있는 홈네트워킹 시스템을 제안하고 테스트베드를 이용하여 성능을 시험하였다. 이때 가시광통신의 다중화에는 LED 비선형성을 극복하기에 적절한 Binary CDMA 방식을 이용하였으며, 역방향 전송에는 적외선을 이용하였다.