1. Ph.D. Student, Dept. of Urban Management, Kyoto Univ., Kyoto 615-8540, Japan.
2. Associate Professor, Dept. of Civil and Environmental Engineering, Yamaguchi Univ., Yamaguchi 755-8611, Japan.
3. Assistant Professor, Dept. of Civil and Earth Resources Engineering, Kyoto Univ., Kyoto 615-8540, Japan.
4. Professor, Dept. of Civil and Environmental Engineering, Ehime Univ., Matsuyama 790-8577, Japan.
5. Professor, Dept. of Urban Management, Kyoto Univ., Kyoto 615-8540, Japan (corresponding author).