1. BBD Technology Co., Ltd. (BBD), 21F, Palm Springs Building, No. 199, Tianfu Avenue, Chengdu 610093, P. R. China
2. Guiyang Institute for Bigdata and Finance, Guizhou University of Finance and Economics, Guiyang 550025, P. R. China
3. School of Financial Technology, Shanghai Lixin University of Accounting and Finance, Shanghai 201209, P. R. China
4. Business School and Advanced Institute of Finance, Sun Yat-Sen University, Guangzhou 510275, P. R. China
5. Center for Financial Engineering, Soochow University, Suzhou 215008, P. R. China
6. College of Mathematics and Statistics, Chongqing University, Chongqing 401331, P. R. China