1. Associate Professor, Graduate School of Engineering, Kyoto Univ., C-Cluster, Katusra Campus, Nishikyo-Ku, Kyoto 615-8540, Japan (corresponding author).
2. Professor, Graduate School of Engineering, Kyoto Univ., C-Cluster, Katusra Campus, Nishikyo-Ku, Kyoto 615-8540, Japan.
3. Research Engineer, Institute of Technology, Tobishima Corporation, 5472 Kimagase, Noda, Chiba 270-0222, Japan.
4. Lecturer, Department of Civil Engineering, Faculty of Engineering, Univ. of Malaya, Kuala Lumpur 50603, Malaysia.
5. Assistant Professor, Graduate School of Engineering, Osaka Univ., Suita, Osaka 565-0871, Japan.
6. Professor, Graduate School of Engineering, Osaka Univ., Suita, Osaka 565-0871, Japan.