1. Division of Computer Science and Engineering, Department of Engineering of Innovation, National Institute of Technology, Tomakomai College, 443 Nishikioka, Tomakomai, Hokkaido 059-1275, Japan
2. Advanced Course of Engineering for Innovation, Division of Electronics and Information Engineering, National Institute of Technology, Tomakomai College, 443 Nishikioka, Tomakomai, Hokkaido 059-1275, Japan
3. Department of Electrical and Electronic Engineering and Computer Science, Graduate School of Science and Engineering, Ehime University, 3 Bunkyo-cho, Matsuyama, Ehime 790-8577, Japan
4. Department of Electrical and Computer Engineering, National Institute of Technology, Kagawa College, 355 Chokushi-cho, Takamatsu, Kagawa 761-8058, Japan
5. Communication and Information Systems Program, Department of Integrated Science and Technology, National Institute of Technology, Tsuyama College, 624-1 Numa, Tsuyama, Okayama 708-8509, Japan