1. Department of Finance, School of Business, East China University of Science and Technology, Shanghai 200237, China
2. Department of Finance, School of Business, Postdoctoral Research Station, Research Center for Econophysics, East China University of Science and Technology, Shanghai 200237, China
3. Department of Finance, School of Business, Department of Mathematics, School of Science, Research Center for Econophysics, East China University of Science and Technology, Shanghai 200237, China