1. Business School of Central South University, Changsha 410081, P. R. China
2. Center for Computational Finance and Economic Agents, University of Essex, Colchester CO4 3SQ, UK
3. Institute of Financial, WenZhou University, Wenzhou 325035, P. R. China
4. International Business School, Shaanxi Normal University, Xian, P. R. China
5. Department of Management Sciences, City University of Hong Kong, Kowloon, Hong Kong