[1] Railway Tech Res Inst, Informat & Commun Technol Div, 2-8-38 Hikari Cho, Kokubunji, Tokyo 1858540, Japan
[2] Chiba Univ, Grad Sch Sci & Engn, 1-33 Yayoi Cho,Inage Ku, Chiba, Chiba 2638522, Japan
[3] Cent Japan Railway Co, Gen Technol Div, 1545-33 Ohyama, Komaki 4850801, Japan
[4] Chiba Univ, Ctr Frontier Med Engn, 1-33 Yayoi Cho,Inage Ku, Chiba, Chiba 2638522, Japan