1. Associate Professor, Institute of Lowland Technology, Saga Univ., 1 Honjo, Saga 840-8502, Japan.
2. Director, Institute of Soft Ground Engineering, 4-1-52 Ohtakara, Saga 840-0811, Japan.
3. Chief Engineer, Shiwa Techno Co., Ltd, 1856-1 Kubotacho Tokuman, Saga 849-0201, Japan.