[1] Res. Inst. of Elec. Communication, Tohoku University
[2] East Japan Railway Company
[3] Info. Technology R and D Center, Mitsubishi Electric Corporation
[4] Koden Electronics Co., Ltd.
[5] Tohoku University, Sendai
[6] East Japan Railway Company, Sendai
[7] Electro-Opt. and Ultrasonics Dept., Info. Technology R and D Center, MELCO
[8] Japan Society of Applied Physics, Institute of Electronics, Info. and Commun. Engineers of Japan