[1] Department of Systems Engineering, Faculty O F Engineering, Shizuoka University, 3-5-1, Johoku, Hamamatsu-shi, 432-8561, Japan
[2] Sony LSI Design Inc. Gohdo-cho134, Hodogaya-ku, Yokohama, Kanagawa 240-0005, Japan
[3] School of Administration and Informatics, University of Shizuoka, 52-1, Yada, Shizuoka-shi, 422-8526, Japan