1. Shanghai Institute of Applied Mathematics and Mechanics, School of Mechanics and Engineering Science, Shanghai University, Shanghai 200072, P. R. China
2. School of Finance and Mathematics, Huainan Normal University, Huainan 232038, P. R. China
3. School of Economics and Management, Tongji University, Shanghai 200092, P. R. China
4. Department of Aeronautics and Astronautics, Fudan University, Shanghai 200433, P. R. China