1. Ph.D. Candidate, Dept. of Urban and Civil Engineering, Ibaraki Univ., 4-12-1 Nakanarusawa-cho, Hitachi 316-8511, Japan (corresponding author).
2. Professor, Dept. of Urban and Civil Engineering, Ibaraki Univ., 4-12-1 Nakanarusawa-cho, Hitachi 316-8511, Japan.
3. Professor, International Institute for Urban Systems Engineering, Southeast Univ., Nanjing 210096, China.