1. Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, 6-1 Kasuga-Koen, Kasuga 816-8580, Japan
2. Research Institute for Applied Mechanics, Kyushu University, 6-1 Kasuga-Kohen, Kasuga 816-8580, Japan
3. Faculty of Arts and Science, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan