1. Department of Urban Engineering, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan
2. Faculty of Education and Human Studies, Akita University, 1-1 Tegata Gakuen-machi, Akita City, Akita 010-8502, Japan
3. Institute of Environmental Science and Engineering, National University of Civil Engineering (NUCE), 55 Giai Phong, Hanoi, Vietnam