1. Faculty of Information and Human Science, Kyoto Institute of Technology, Matsugasakihashigami-cho, Sakyo-ku, Kyoto, Kyoto 606-8585, Japan
2. Faculty of Culture and Information Science, Doshisha University, 1-3 Tatara Miyakodani, Kyotanabe, Kyoto 610-0394, Japan
3. Advanced Intelligence Project, RIKEN, 1-4-1 Nihonbashi, Chuo-ku, Tokyo 103-0027, Japan
4. Center for Brain Science, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japa
5. Information and Management Systems Engineering, Nagaoka University of Technology, 1603-1 Kamitomiokamachi, Nagaoka, Niigata 940-2188, Japan