1. College of Mathematics and Computing Science, Changsha University of Science and Technology, Changsha 410114, China
2. Business School, Central South University, Changsha 410012, China
3. Institute of Policy and Management, Chinese Academy of Science (CAS), Beijing 100190, China
4. Department of Applied Mathematics, University of Western Ontario, London, ON, Canada N6A 5B7
5. Rutgers Business School, Rutgers University, Piscataway, NJ 08854, USA