1. College of Economics, Shenzhen University, Shenzhen 518055, Guangdong Province, P.R. China
2. Department of Statistics and Data Science, Southern University of Science and Technology, Shenzhen 518055, Guangdong Province, P.R. China
3. School of Statistics and Mathematics, Yunnan University of Finance and Economics, Kunming 650221, Yunnan Province, P.R. China