1. Associate Professor, Graduate School of Science and Technology, Chiba Univ., 1-33 Yayoi, Inage, Chiba 263-8522, Japan. E-mail: yharada@faculty.chiba-u.jp
2. Professor, Dept. of Design and Architecture, Faculty of Engineering, Chiba Univ., 1-33 Yayoi, Inage, Chiba 263-8522, Japan. E-mail: morita@faculty.chiba-u.jp