1. College of Computer Engineering and Applied Mathematics, Changsha University, Changsha, Hunan 410022, China
2. Department of Ultrasound, Hunan Provincial Maternal and Child Health Care Hospital, Changsha, Hunan 410008, China
3. Department of Banking and Finance, Monash University, Clayton, Victoria 3168, Australia
4. Department of Optoelectronic Engineering, Jinan University, Guangzhou, Guangdong 510632, China