1. Senior Research Engineer, Civil Engineering Project, Access Network Service Systems Laboratories, Nippon Telegraph and Telephone Corp., 1-7-1, Hanabatake, Tsukuba, Ibaraki 305-0805, Japan (corresponding author). ORCID: .
2. Research Engineer, Civil Engineering Project, Access Network Service Systems Laboratories, Nippon Telegraph and Telephone Corp., 1-7-1, Hanabatake, Tsukuba, Ibaraki 305-0805, Japan.
3. Professor, Dept. of Engineering Mechanics and Energy, Univ. of Tsukuba, 1-1-1, Tenodai, Tsukuba, Ibaraki 305-8573, Japan. ORCID: .
4. Professor, Dept. of Civil and Environmental Engineering, Toyo Univ., 2100, Kujirai, Kawagoe, Saitama 350-8585, Japan.