Affiliation: | 1. 4-13-11 Hachi-Hom-Matsu-Minami, Higashi-Hiroshima, 739-0144 Japan;2. Faculty of Education, Oita University, Dannoharu Oita-city, 870-1192 Japan;3. Department of Mathematics, Graduate School of Education, Hiroshima University, Higashi-Hiroshima, 739-8524 Japan;4. Department of Intelligent Mechanical Engineering, Hiroshima Institute of Technology, 2-1-1 Miyake Saeki-ku, Hiroshima, 731-5193 Japan |