1. Department of Statistics and Finance, University of Science and Technology of China, Hefei, Peoples Republic of China
2. School of Mathematics and Statistics and Research Institute of Mathematical Sciences (RIMS), Jiangsu Provincial Key Laboratory of Educational Big Data Science and Engineering, Jiangsu Normal University, Xuzhou, Peoples Republic of China
3. Department of Mathematics, Illinois State University, Normal, IL, USA
4. Department of Computer Science, University of Texas at San Antonio, San Antonio, TX, USA
5. School of Information Technology, Illinois State University, Normal, IL, USA