• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.11 no.6
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• pp.247-253
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• 2011

In this paper, we propose and implement the automated brightness control system using distance measuring sensor for reducing the power consumption of emotional lighting device. In order to reduce the power consumption of emotional lighting devices which express continuous color changes, the proposed device measures the distance continuously using ultrasonic sensor and by using this, it also performs PWM Dimming control. The lighting device is composed of micro controller, LED driver, ultrasonic sensor, communication module and so on. And the device performs the real time brightness control by adapting the measured distance information from ultrasonic sensor to PWM signals. From this experiment, we implement the active lighting system which minimizes unnecessary power consumption during user's absence by adapting existing energy reducing techniques.

• Journal of IKEEE
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• v.21 no.4
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• pp.368-374
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• 2017

In this Paper, we developed a low power type LED security light using LED lighting that substitutes a 220[V] commercial power source for a solar cell module instead of a halogen or a sodium lamp. in addition, a PWM type drive control circuit is designed to minimize the heat generation problem and the drive current of the LED drive controller. in developed system, The light efficiency measurement value is 93.6[lm/W], and a high precision temperature sensor is used inside the controller to control the heat generation of the LED lamp. In order to eliminate the high heat generated from the LED lamp, it is designed to disperse quickly into the atmosphere through the metal insertion type heat sink. The heat control range of LED lighting was $50-55[^{\circ}C]$. The luminous flux and the lighting speed of the LED security lamp were 0.5[s], and the beam diffusion angle of the LED lamp was about $110[^{\circ}C]$ by the light distribution curve based on the height of 6[m].

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.25 no.1
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• pp.1-8
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• 2011

In this paper, the method to calculate chromaticity coordinate from spectral power distribution of LED is presented. Also, inverse tri-stimulus algorithm to find mixed luminance of red, green, blue LED from targeted luminance and chromaticity coordinate is proposed. Besides, digital light color control system of LED lamp applied this algorithm has been developed. In experiments, each chromaticity coordinate of red, green, blue LED calculated from this algorithm has relative percentage error of few % to measured values. Digital code is drawn from inverse tri-stimulus algorithm, and measured values of luminance and chromaticity coordinate of LED lamp digitally controlled by this code also have relative percentage error within a few % to targeted luminance and chromaticity coordinate.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.8
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• pp.2999-3004
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• 2010

In comparison with some other light sources, LED has merits such as long lifetime, pollution free, and high energy efficiency. Lately, due to development of LED with high brightness and capacity, LED, which has been applied in display system only, has applied in the field of lighting system. As power LED for lighting system can be burned out by heat problem, the driving current of power LED has to be controlled below the designed value. In this paper, power LED photovoltaic lighting system, which has the current limitting function, has been described. After photovoltaic power is generated from PV panel. it is charged into a battery. And then, after the charged power is converted to DC24[V] through a boost DC-DC converter, it is supplied to power LED at night. It has been validated by designing and testing of 72[W] power LED lighting system, which includes a PV charger, a boost DC-DC converter and a current limiter for driving power LED.

• Proceedings of the KIPE Conference
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• 2018.07a
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• pp.304-305
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• 2018

현재 공장 단지 내에 구비된 조명 시설은 SMPS, DC/DC컨버터 및 LED 램프 등이 하나의 모듈로써 구성되어 있다. 이처럼 일체형으로써 사고 및 고장 발생 시, 모듈 전체를 수리 또는 교체되어야 하므로 시간과 경제적으로 많은 불편이 따른다. 본 논문에서 제안하는 시스템은 각각을 분리한 집중형 LED 드라이버로써 정류기와 DC/DC 컨버터를 분리하여 구성하였다. 각각의 LED의 Dimming 제어를 위해서, 전력선에 주파수 성분을 첨가하여 주파수 정보에 따른 Dimming 제어를 실시함으로써, 따로 통신선 구비가 필요 없는 집중형 LED 구동 드라이버를 제안하였다. 제안하는 방식의 타당성을 검증하기 위해 PSIM 시뮬레이션을 통하여 그 과정을 증명하였다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.4
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• pp.1474-1479
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• 2012

Rotational smart lighting control system provides artificial light to plants on planting board by rotational lighting system. As the lighting system of existing plant factory has high cost problem due to the installation for many lighting equipments, the lighting system was developed to rotate less number of lighting equipments to reduce cost. In this paper, the illuminance, luminous flux and photosynthetic photon flux density(PPFD) that plants need to grow were calculated. And the light intensity at each measured location considering the rotational speed of blade were analyzed by the simulation and the experiment.

• Journal of Satellite, Information and Communications
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• v.7 no.2
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• pp.25-29
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• 2012

In this paper, we implemented LED beam forming communication system controlled by stepping motor. ATMega1284 was used as a MCU of main control board which has two main external IO, one is RS232 for connection with PC, the other is PORT for connection with motor driving board. Stepping motor rotated 360 degree when provided 160 clock and its rotation radius was increased by Archimedian Spiral. So LED can provide its light anywhere in the space and its beam forming was controlled by PC connected with RS232 of main control board. The action of beam forming was verified via actual HW/SW implementation.

• Proceedings of the KIPE Conference
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• 2011.07a
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• pp.224-225
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• 2011

본 논문은 하나의 제어 IC로 이중출력 각각 독립 제어가 가능한 LLC 공진형 컨버터를 제안한다. 기존의 이중출력 LLC 공진형 컨버터의 경우 master 출력전압만 제어가 가능하므로, slave 출력의 정밀제어를 위해 별도의 DC/DC 컨버터가 필요하며, 이는 시스템의 전력 변환 효율을 떨어뜨리고 제작단가를 증가시키는 단점이 있다. 반면, 제안된 회로는 LLC 공진형 컨버터의 이중출력을 하나의 제어 IC로 주파수 및 시비율 각각 가변하는 방식으로 개별적 제어가 가능하므로 부하 및 입력전압 조건과 무관하게 모든 출력 전압의 제어를 정밀하게 할 수 있는 장점이 있다. 따라서 별도의 DC/DC 컨버터 사용이 불필요하므로 고효율 및 저가격의 특징을 가질 수 있다. 본 논문에서는 제안된 회로의 타당성 검증을 위해 이론적 분석결과를 제시하고 40W급 LED 조명회로에 적용한 실험 결과를 바탕으로 그 우수성을 확인한다.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.1
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• pp.23-30
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• 2014

Recently, Light Emitting Diode(LED) light is changing the light equipment, which was considered just as a power-controlled device in home-network, into a IT convergence device by combining illumination function with wireless communication. As a result, Visible Light Communication(VLC) becomes a more practical solution to ubiquitous networks due to the more spread of LED light. One of representative applications using VLC is a VLC-based indoor navigation system which can provide high-accuracy indoor localization. In this paper, we model and implement a VLC based-indoor navigation system in which a fluorescent light type of LED lamp, which is normally used in large buildings, and smart devices, which are usually used by users, are utilized as main components for indoor navigation. Subsequently, it is expected that the paper can contribute to make VLC applications be more active.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.1
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• pp.467-477
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• 2006

최근 조명기술의 발달에 따라 가장 각광을 받고 있는 것이 LED 소자를 이용한 발관체이다. 이미 육상의 교통신호등 뿐만 아니라, 차량 방향지시등, 빽라이트등 다양한 용도로 사용되고 있으며, 해상에도 등부표의 광원용으로 사용되고 있다. 이러한 추세에 맞추어, 항을 진입하는데 가능 필요한 도등의 광원용으로 LED를 사용하고 이를 제어하는 기술을 연구개발하여 전세계에서 처음으로 부산 신항에 설치하여 효과를 분석하였다.