• Transactions on Electrical and Electronic Materials
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• 제12권6호
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• pp.253-257
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• 2011

This study was carried out to solve problems such as radio frequency band depletion, confusion risk, and security loss in existing visible wireless communication systems, and to determine the applicability of next-generation networks. A light-emitting diode (LED) light communication system was implemented with a controlling switching light module using the ATmega16 micro-controller. To solve the existing modulation effect and disturbance in visible light communication, an integrated interface was evaluated with a driving light module and analyzes its reception property. A transmitter/receiver using the ATmel's micro-controller, high-intensity white LED-6 modules, and infrared sensor KSM60WLM and visible sensor TSL250RD were designed. An experiment from the initial value of distance to 2.5 m showed 0.46 V of the voltage loss, and if in long distance, external light interference occurred and light intensity was lost by external impact and thus data had to be modified or reset repeatedly. Additionally, when we used 6 modules through the remote controller's lighting dimming, data could be transmitted up to 1.76 m without any errors during the day and up to 2.29 m at night with around 2~3% communication error. If a special optical filter can reduce as much external light as possible in the integrated interface, the LED for lighting communication systems may be applied in next generation networks.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.1574_1575
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• 2009

This paper investigates the reduction of RE(Radiated Emission) noise in a high power LED module circuit using PWM(Pulse Width Module) switching controller circuit. Poorly designed LED lighting module can experience the RE and CE(Conducted Emission) noise problem. This paper propose the reduction of noise source and improvement of EMI filter design in a high power LED lighting module. The experimental and simulation results showed that reduce the RE noise level effectively.

• 한국컴퓨터산업학회논문지
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• 제6권5호
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• pp.741-748
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• 2005

형광램프용 전자식 안정기의 효율개선 및 램프의 수명연장을 위하여 강유전체 커패시터와 시간지연스위칭회로로 구성된 절전모듈을 개발하고 적용하였다. 절전모듈에 사용된 강유전체 세라믹스를 이용하여 형광램프의 부저항특성과 최적화를 시키고, 시간지연회로를 통하여 점등초기 예열형에서 비예열형으로 스위칭시켜 점등 중 필라멘트에서 소비되는 전력을 제거함으로써 약 2W의 소비전력을 감소시켜 효율개선을 실현하였으며, 역기전력 제거기능을 통하여 점등 초기 형광램프 필라멘트에 가해지는 충격을 최소화함으로써 형광램프의 수명을 연장시켰다.

• Journal of electromagnetic engineering and science
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• 제16권4호
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• pp.214-218
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• 2016

In this paper, we present an ambient light backscatter communication design that enables Internet of Things (IoT) devices to communicate through the backscattering ambient light emitted from lighting infrastructure or sunlight. The device can selectively modulate ambient light by switching a liquid crystal display (LCD) shutter located on its surface, so that a nearby smart device, which includes a photodiode or a camera, can demodulate this backscattered light information. To verify the practicality of the proposed concept, we design an IoT device equipped with a commercial LCD shutter and a microcontroller. Our device produces ambient light backscattered data at a speed of 100 bps, and these data are successfully decoded by a commercial photodiode module 10 cm away from the IoT device. We believe that our ambient light backscatter communication design is appropriate for implementation in various IoT applications.