[1] Shanghai Jiao Tong Univ, Dept Math, Shanghai 200240, Peoples R China
[2] French Naval Acad Brest Lanveoc, IRENAV Res Inst, F-29290 Brest, France
[3] Kyoto Univ, Grad Sch Human & Environm Studies, Kyoto 6068501, Japan
[4] Univ Rouen, CNRS, UMR 6085, F-76801 St Etienne, France
[5] Wuhan Univ, Sch Math & Stat, Wuhan 430072, Peoples R China
[6] City Univ Hong Kong, Dept Math, Hong Kong, Hong Kong, Peoples R China