Institution: | (1) Computing and Communications Center, Kyushu University, 812-8581 Fukuoka, Japan;(2) Department of Computer Science and Information Mathematics, The University of Electro-Communications, 182-8585 Chofu, Japan;(3) Graduate School of Mathematics, Kyushu University, 812-8581 Fukuoka, Japan;(4) Graduate School of Science, Kyoto University, 606-8502 Kyoto, Japan |