Masamichi Isokawa (isokawa@cc.hirosaki-u.ac.jp)
Masato Wayama (wayama@cc.hirosaki-u.ac.jp)
Toshio Shimizu (slsimi@si.hirosaki-u.ac.jp)
Department of Information Science,
Faculty of Science, Hirosaki University
Bunkyou-cho 3, Hirosaki 036 Japan