1. NIIGATA UNIVERSITY, Graduate School of Science and Technology(8050, Ikarashi-2, Nishi-ku, Niigata-shi, Niigata 950-2181, Japan)
2. NIIGATA UNIVERSITY, Department of Civil Engineering(8050, Ikarashi-2, Nishi-ku, Niigata-shi, Niigata 950-2181, Japan)