1. Faculty of Science, Kanagawa University, Kanagawa, Japan
2. Center for Advanced Intelligence Project, RIKEN, Tokyo, Japan
3. School of Computer Science, Tokyo University of Technology, Tokyo, Japan
4. College of Science and Engineering, Aoyama Gakuin University, Kanagawa, Japan
5. Faculty of Advanced Science and Technology, Ryukoku University, Shiga, Japan
6. Institute of Scientific and Industrial Research, Osaka University, Osaka, Japan