Jae Sang Cha

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"Green" and energy-efficient wireless communication schemes have recently experienced rapid development and garnered much interest. One such scheme is visible light communication (VLC) which is being touted as one of the next generation wireless communication systems. VLC allows communication using multi-color channels that provide high data rates and(More)
Recently there have been many studies of power systems with a focus on "New and Renewable Energy" as part of "New Growth Engine Industry" promoted by the Korean government. "New And Renewable Energy"-especially focused on wind energy, solar energy and fuel cells that will replace conventional fossil fuels-is a part of the Power-IT Sector which is the basis(More)
Recently, watermarking based data transmission techniques using terrestrial digital TV signal have been proposed since they are also cost-free and can overcome the limitations of GPS. However, in the previous watermarking based methods, the detection accuracy is low and additional data rate is too low. Thus, we propose the throughput enhancement method by(More)
Path mapping and finding the desired path for a mobile cleaning robot in order to perform cleaning efficiently is a difficult task. Moreover, in complex indoor environments, avoiding collision with other furniture or equipment is a big problem for mobile cleaning robot. In the case wireless control link should be robust for accurate moving along the desired(More)