E-mail addresses: dailei1989@sjtu.edu.cn (L. Dai), Corresponding author. State Key Laboratory of Ocean Engineering, Shanghai Jiao Tong University, Shanghai 200240, China. Tel: +86 21 62933091; fax: +86 21 62933163.E-mail addresses:hhu@sjtu.edu.cn (H. Hu), E-mail addresses:zhangdifanny@gmail.com (D. Zhang).