1. School of Mathematics, Hunan Provincial Key Laboratory of Intelligent Information Processing and Applied Mathematics, Hunan University, Changsha, Hunan, China
2. School of Computer Science and Engineering, Southeast University, Nanjing, Jiangsu, China
3. Centre for Artificial Intelligence, Faculty of Engineering Information Technology, University of Technology Sydney, Ultimo, NSW, Australia
4. Science Program, Texas A&M University at Qatar, Doha, Qatar