1. The Center for Data Science Education and Research, Shiga University, Hikone, Shiga 522-8522, Japan
2. Faculty of Science and Technology, Oita University, Oita 870-1192, Japan
3. Rhythm-Based Brain Information Processing Unit, RIKEN Center for Brain Science, Wako, Saitama 351-0198, Japan
4. Graduate School of Informatics, Kyoto University, Kyoto 606-8501, Japan