• Journal of Digital Convergence
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• v.19 no.12
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• pp.457-462
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• 2021

As South Korea is a mountainous topography, installation of tunnel is essential for construction of expressway in straight lines. According to "2019 Road Bridge and Tunnel Status Report", there are 2,682 tunnels in Korea with total length of 2,077km. Tunnels take up 1.9% of total road length and the number of tunnel increased by 94% with 1,300 newly constructed tunnels over the 10 years. According to domestic and foreign researches, a long tunnel over 1km in expressway has dark lightings and monotonous wall design which decrease driver's concentration and make the driver feel bored. This leads to feeling fatigue and drowsiness more easily. In response, Korea Expressway Corporation installed design lighting that increases attentiveness on 10 tunnels with total length over 3km by 2020. To reduce the risks of accident that may happen inside the tunnel, this study conducted a comparative analysis on characteristics of each type of LED landscape lighting installed inside the expressway tunnel. The study aimed on providing the basic material for effective installation of LED landscape lighting for securing driving stability, reducing fatigue, and lowering the risk of drowsiness.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.6
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• pp.1178-1182
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• 2011

The best methods for distribution controled of LED lighting fixtures is control to designed LED chip array, lens and reflector. However, lens design need distribution design to reflector for low-wattage LED lighting because of difficulty of production and reduction of light efficiency. In addition, it needs maximize of thermal performance to improve the efficiency and reliability of device. As a result, for the height of reflector 40[mm] and Inclination 25[$^{\circ}$], we can see the best distribution properties, and, in the thermal properties, junction temperature MCPCB 62.9 [$^{\circ}C$], FR4 PCB 89.6 [$^{\circ}C$], FR4 PCB from Via-hole is 63.1 [$^{\circ}C$]. it may improve for thermal properties for makes the Via-hole.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2009.10a
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• pp.15-18
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• 2009

Photopia, LightTools, and ASAP are typical software for optical design of a luminaire. Through using various lighting simulation software some different results can be found under the same conditions. Therefore, the purpose of this paper is to compare simulated photometric data and values illuminance of different types of LED prism luminaires under the same conditions. Then, LED prism luminaires were divided into the linear type and the planar type. Also three kinds of prism angles were divided into $30^{\circ}$, $45^{\circ}$, and $60^{\circ}$. In addition, the reasons for such differences were analyzed.

• Proceedings of the Optical Society of Korea Conference
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• 2007.07a
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• pp.15-16
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• 2007

A design of a light coupler between a LED and a very thin light guide (0.2mm thickness) is presented. Due to the light guide's very thin thickness, conventional light couplings between LEDs and light guides do not provide enough coupling efficiency. We investigate two different coupling methods: side coupling using a complex-shaped lens and bottom coupling using a grating. This paper presents a draft design of the first approach which couples light from 0.4mm LED to 0.2mm light guide without significant losses.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2001.11a
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• pp.129-132
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• 2001

LED는 오랫동안 가전제품이나 각종 기계의 표시소자로 사용되어 왔으나, 최근 LED가 고취도화 되면서 LED를 이용한 조명제품 개발이 활발하게 이루어지고 있다. 본 논문에서는 RGB LED를 이용한 LED 전구를 설계하기 위해 광학설계 프로그램 LightTools을 이용하였다. RGB LED의 비율과 배치에 따른 태양광과 비슷한 백색광을 얻기 위해 RGB LED의 비율을 R:G:B=1:1.5:3, 하여 CIE 색좌표 x:y=0.342: 0.291, 색온도 5100[K]의 값을 얻었다. RGB LED의 대칭, 원형, 간격별 배열에 따른 배치를 통하여 색좌표 x:y= 0.337: 0.297인 백색광을 얻었다. 이 같은 결론을 바탕으로 RGB LED전구를 설계하였다.

• Journal of the Korean Society of Marine Environment & Safety
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• v.16 no.2
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• pp.235-240
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• 2010

In order to substitute incandescent lamps, a power supply device for 7W class LED lamps which are environmentally friendly and energy saving is designed LED lamps consist of a multitude of chip LED connected in parallel and series. 11ms it is necessary to supply LED lamps with DC voltage and current. However, when LED lamps are in use, they are connected directly to AC 220V. This is why we need to have AC/DC, DC/DC power converters including a control system of voltage and current. For this, a transformerless and simple LED lamp driver is designed 조ich can control the current and output voltage for LED string of LED lamp.

• Journal of Advanced Navigation Technology
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• v.20 no.1
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• pp.99-106
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• 2016

Wearable display market is a consistently growing field to handle a smart device with ease. Wearable display is an efficient device that can show the information to the user. In this paper, propose the scheme of a wearable display using LED and implement it including controlling remotely with BLE. Traditional outdoor LED display requires the dedicated controller and its software. Therefore, to control those LED display, it should implement a driver and its own way of communication. The proposed method is to ensure the independence and extensibility by separating driver module and communication module for controlling LED display. In addition, by adopting a short-range communication with Bluetooth 4.0 and a LED driver with low-power technology, it can be showed to control system configuration and display with a smart device.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.5
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• pp.1053-1059
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• 2011

DMX512 protocol is a typical protocol which controls LED lighting system. It has a strong feature and can be used to a lot of lighting system. But LED control system with cable has a few problem because they have a lot of control cables. It is very difficult to set up the complex lighting. Furthermore if it is set up it is not easy to keep and recover the system from the out of order. So it is required Wireless Lighting Control System. This paper describes the proposal, design, and implementation of a novel method which can provide versatile light effects with the increased capability of the mobility and the number of universes for Wireless Lighting system. And then we implement experiment environment to control indoor lighting system controled by ZigBee and WLAN converter not having complicating control line. Data frames are transferred to DMX512 device by encapsulation and decapsulation to control color LED. In the same time give the method to solve the data bottleneck problem which can be comes out because of speed difference between Heterogeneous network and measure performance of control system.

• Proceedings of the KIPE Conference
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• 2013.07a
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• pp.177-179
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• 2013

This paper presents an LED driver which requires a high voltage gain (5-6 times). To achieve a high voltage gain, the tapped-inductor boost converter topology was used and through the analysis of converter's steady-state and its dynamic characteristics, the product design's reliability and validity were verified.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.4
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• pp.30-36
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• 2015

The principle of an illumination and projection system including LED light sources for a spot type stage lighting system was presented, and its optical system was designed with optimizing parameters by the analytical methods. A dichroic mirror incorporated with an illumination system to optimizing LED source positions and to obtain the compact system. The projection system was optimized with specific constraints such as a chromatic aberration, distortion aberration and angle of incidence angles. Optimized design system has a beam angle from $10^{\circ}$ to $45^{\circ}$, and its illuminance was 4,500lux at distance of 6m on the work plane.