1. Graduate School of International Resource Sciences, Akita University, 1-1 Tegata Gakuenmachi, Akita 010-8502, Japan
2. Department of Systems, Control and Information Engineering, National Institute of Technology, Asahikawa College, 2-2-1-6 Syunkodai, Asahikawa 071-8142, Japan
3. Division of Sustainable Resources Engineering, Faculty of Engineering, Hokkaido University, Kita 13, Nishi 8, Kita-ku, Sapporo 060-8628, Japan