Affiliation: | (1) Department of Information Science, Faculty of Engineering Utsunomiya University, 2753 Ishii-machi, Utsunomiya-shi, Tochigi-ken, 321-8585, Japan;(2) Department of Computer Science, Meiji University, 111 Higashi-Mita, Tama-ku, Kawasaki, 214, Japan |