1. Department of Electrical and Electronic EngineeringUtsunomiya University Yoto Utsunomiya Tochigi Japan
2. Department of Innovative Electrical and Electronic EngineeringNat. Inst. of Technology, Oyama College Nakakuki Oyama Tochigi Japan
3. Artificial Intelligence Research CenterNat. Inst. of Advanced Industrial Science and Technology Umezono Tsukuba Ibaraki Japan
4. Department of Electrical & Electronic EngineeringTokai University Kitakaname Hiratsuka Kanagawa Japan