1. School of Mathematics and Statistics, Anhui Normal University, Wuhu, Anhui, China
2. MOE-LCSM, School of Mathematics and Statistics, Key Laboratory of Control and Optimization of Complex Systems, College of Hunan Province, Hunan Normal University, Changsha, China
3. College of Mathematics and System Sciences, Xinjiang University, Ürümqi, China
4. Science Program, Texas A&M University at Qatar, Doha, Qatar