• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.19 no.6
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• pp.688-697
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• 2008

In this paper, an analysis method for indoor optical wireless channel properties based on photon model is presented for characterization of communication environment. In contrast to radio waves, optical waves have very short wave-lengths and very high frequencies, so that material properties become important. Channel models including diffuse reflections and absorption effects due to material surface textures make conventional electromagnetic wave analysis methods based on ray tracing consume enormous time. To overcome these problems, an analysis method using photon model is presented that approximates light intensity by a density of photons. The photon model ensures that simulation time is within a predictable limit.

• Proceedings of the Optical Society of Korea Conference
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• 2004.07a
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• pp.28-29
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• 2004

Optical wireless mobile communications have the potential to provide wide bandwidth and security . We have proposed and designed the 2-dimensional tracking optical receiver systems for optical wireless mobile communication. The receiver system consist of 4${\times}$4 photodiode array can receive optical signal from the transmitter. The room size is 5${\times}$5m$^2$ and the room height is 3m.

• Proceedings of the Korea Society for Industrial Systems Conference
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• 2009.05a
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• pp.77-81
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• 2009

논문은 지능형 자동차 개발을 위한 마이크로마우스를 활용한 차량-도로 간 통신, 모터제어, 영상처리와 물체감지 센서들을 활용한 도로 상황정보 인식 시스템 등을 활용하여 지능형 자동차의 운행을 구현하고 테스트 할 수 있다. 이를 활용하여 검증된 기술들을 실제 차량에 적용하기 위해서 다양한 실험과 테스트를 실시한다. 또한 누구나 쉽게 간단한 마이크로 컨트롤러를 통한 지능형 자동차를 위한 다양한 아이디어를 접목할 수 있도록 시스템을 설계한다. 이를 활용하여 영상처리를 통한 차선인식과, 직진 좌회전 및 도로의 교통표시마크를 읽어 들여 차체를 컨트롤하고 차량-도로간 통신을 이용해서 신호등의 정보를 입력받아 교차로를 안전하게 통과하게 된다. 또한 앞 차량을 인식하여 자동으로 속도조절과 차량 간 거리를 유지하는 시스템을 구현한다.

• Journal of Satellite, Information and Communications
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• v.8 no.1
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• pp.71-76
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• 2013

In this paper, a transceiver of VLC (Visible Light Communication) using LED white lighting has been implemented. The transmitted waveforms of LED and PD (Photo Diode) of the received signal are analyze to restore VLC data. Audio signal was successfully transmitted to demonstrate possibility and potential of optical wireless communication systems. Various modulation formats are considered to evaluate and compare performance in diverse channel conditions.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.14 no.4
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• pp.77-83
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• 2014

Visible light communication is a converging communication by technologies that enable solutions using the LED Lighting. There is a need to research about it in order to improve the performance of the wireless communication by using a Color LED and improve the efficiency of data. In this paper, Assume the General indoor communication environment and LED communication systems based on CSK-OFDM applied to a MIMO communication system, We studied about transmitting method of more efficient communication. After performing the simulation based on IEEE 802.15.7 Standardization, as a result of the analysis of performance, it was confirmed the there is a significant impact on the performance of SNR and BER performance by the transmitting method based on MIMO and external noise using the LED communication system based on CSK-OFDM.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.2
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• pp.303-310
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• 2014

We show improved throughput scaling laws for an ultra-wide band (UWB) ad hoc network, in which n wireless nodes are randomly located. First, we consider the case where a modified hierarchical cooperation (HC) strategy is used. Then, in a dense network of unit area, our result indicates that the derived throughput scaling depends on the path-loss exponent ${\alpha}$ for certain operating regimes due to the power-limited characteristics. It also turns out that the HC protocol is dominant for 2 < ${\alpha}$ < 3 while using the nearest multihop (MH) routing leads to a higher throughput for ${\alpha}{\geq}3$. Second, the impact and benefits of infrastructure support are analyzed, where m base stations (BSs) are regularly placed in UWB networks. In this case, the derived throughput scaling depends on ${\alpha}$ due to the power-limited characteristics for all operating regimes. Furthermore, it is shown that the total throughput scales linearly with parameter m as m is larger than a certain level. Hence, the use of either HC or infrastructure is helpful in improving the throughput of UWB networks in some conditions.

• Journal of IKEEE
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• v.24 no.2
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• pp.579-585
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• 2020

In this study, we used byte-inversion transmission method to prevent the flicker of lighting source in a visible light data communication link. In the transmitter, the non-return-to-zero (NRZ) signal with 9.6 kbps was on-off keying (OOK) modulated with a 100 kHz square wave carrier and byte-inversion signal was added after each byte to make the average optical power of the light-emitting diode (LED) constant. In the receiver, we used a band-pass filter to eliminate the interference of the 120 Hz noise which was induced from the adjacent light lamps, and an OOK demodulator to recover the original NRZ signal This scheme is useful in constructing wireless data networks using the illumination of visible light lamps.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.17 no.5
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• pp.143-150
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• 2018

With the rapid development of RF based high speed wireless communication technology, devices that can be applied to IoT networks based on RF bandwidth are rapidly spreading, nevertheless, the development speed of the RF communication is not possible to keep up with the spread of the RF band for wireless communication. In this situation, OWC technology that uses visible light source as a transmitter is attracting attention as a technology that can overcome the band exhaustion problem of RF based wireless communication technology. Although, due to the distortion of the LED illumination shape by camera exposure time and LED blinking period, the LED illumination detection rate is degraded and the RoI setting is inaccurate. In this paper, we propose an adaptive median filter applied LED illumination detection algorithm for low rate CamCom, it is possible to detect a clear RoI and LED illumination. This research will be able to play a role as a complementary material of RF based wireless communication technology efficiently.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2012.10a
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• pp.11-12
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• 2012

In this paper, efficient visible light communication technology LED (Light Emitting Diode) lighting through the existing infrared sensor used for performance analysis of transmitting and receiving is possible. LED utilizes lighting by changing light into electricity. Lighting features while maintaining the basic principles of flashing LED and PD (Photo Diode) to send and receive communications from LED lighting communication convergence principle be realized simultaneously enabling. Multiple IT applications under the basic structure of LED technology development, and the current was encountered in real life. LED lighting anywhere with wireless communication technology that can, in order to ~ 1m above the initial value by taking advantage of the system H/W and infrared sensors(PD) are widely used in the entire system that can improve the speed of visible light data transmission system is finished. LED module that is used to communicate whether the performance analysis, For forecasting and communication distance on the LED and infrared sensor configuration of the implementation of the research is to study about the possibility of application methods and indicates.

• Proceedings of the Korea Society for Industrial Systems Conference
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• 2003.11a
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• pp.207-210
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• 2003

현재 무선 인터넷 환경은 음성 서비스 위주의 개인 사용자 시장이 한계에 도달하면서 이동 통신의 무선 단말기를 통하여 다양한 비즈니스를 할 수 있는 B2B 전자상거래 솔루션이 확대되고 있고, 모바일 데이터서비스 시장의 비중이 점차 확대되고 있다. 이러한 데이터 서비스 교환에 XML문서를 사용 할 경우, 데이터의 상호 처리 능력을 향상시키고 데이터의 공용성과 프로그램의 유용성을 향상시키는데 필요한 비용과 노력을 절감 할 수 있다. 따라서 본 논문에서는 모바일을 위한 M-commerce에 대한 현황을 살펴본 뒤, 모바일 환경에서 사용 할 수 있는 플랫폼에 대하여 살펴보았고, 향후 연구 방안으로는 모바일에서의 실시간 쇼핑몰 설계 및 구현과 분산 환경에서의 모바일 쇼핑몰을 설계 구현 할 예정이다.