1. Department of Assets Management, Chongqing Technology and Business University, Chongqing, China
2. School of Mathematics and Statistics, Chongqing Technology and Business University, Chongqing, China
3. School of Mathematics and Big Data, Dezhou University, Dezhou, China
4. Department of Financial and Actuarial Mathematics, Xian Jiaotong-Liverpool University, Suzhou, China