1. Graduate School of Information Science and Electrical Engineering, Kyushu University,Fukuoka,Japan
2. Center for Japan-Egypt Cooperation in Science and Technology, Kyushu University,Fukuoka,Japan
3. RIKEN-AIP,Computational Learning Theory Team,Fukuoka,Japan
4. Kyushu University,Computational Learning Theory Team, Faculty of Arts and Science,Fukuoka,Japan