[1] China Univ Min & Technol, Sch Math, Xuzhou 221116, Jiangsu, Peoples R China
[2] Nanjing Univ, Dept Math, Nanjing 210093, Jiangsu, Peoples R China
[3] Hong Kong Polytech Univ, Dept Civil & Environm Engn, Hong Kong, Peoples R China
[4] McGill Univ, Desautels Fac Management, 1001 Rue Sherbrooke West, Montreal, PQ H3A 1G5, Canada