1. Department of Information and Management, Prefectural University of Hiroshima, 1-1-71 Ujinahigashi, Minami-ku, Hiroshima-city, Hiroshima 734-8558, Japan,
2. Department of Chemistry and Biology, National Institute of Technology, Fukui College, geshi-cho, Sabae-city, Fukui 916-8507, Japan,
3. Graduate School of Engineering, University of Hyogo, 2167 Shosha, Himeji-city, Hyogo 671-2280, Japan