1. School of Statistics and Mathematics, Yunnan University of Finance and Economics 1 , Kunming, Yunnan 650221, China
2. School of Economics and Management, Beihang University 2 , Beijing 100191, China
3. School of Economics, Dongbei University of Finance and Economics 3 , Dalian 116025, China
4. Interdisciplinary Research Institute of Data Science, Shanghai Lixin University of Accounting and Finance 4 , Shanghai 201209, China
5. Department of Applied Mathematics, College of Applied Science, Kyung Hee University 5 , Yongin 17104, Republic of Korea