1. Ph.D. Student, Dept. of Hydraulic and Ocean Engineering, National Cheng Kung Univ., Tainan, Taiwan 701. E-mail: n8889113@ccmail.ncku.edu.tw
2. Professor, Dept. of Hydraulic and Ocean Engineering, National Cheng Kung Univ., Tainan, Taiwan 701 (corresponding author). E-mail: cjhuang@mail.ncku.edu.tw
3. Professor, Dept. of Hydraulic and Ocean Engineering, National Cheng Kung Univ., Tainan, Taiwan 701. E-mail: jinwu@mail.ncku.edu.tw