1. College of Civil Engineering and Architecture, Zhejiang University, Hangzhou, P. R. China;
2. Department of Engineering Science and Ocean Engineering, National Taiwan University, Taipei, Taiwan, R. O. China;
3. Ocean College, Zhejiang University, Zhoushan, P. R. China;
4. State key lab of Hydraulics and Mountain River Engineering, Sichuan University, Sichuan, P. R. China