1. School of Automation and Electronic Information, Xiangtan University, Xiangtan 411105, China
2. School of Physics and Optoelectronic Engineering, Xiangtan University, Xiangtan 411105, China
3. School of Computer Science & School of Cyberspace Science, Xiangtan University, Xiangtan 411105, China
4. School of Electrical, Electronic and Computer Engineering, University of Western Australia, Crawley, WA 6009, Australia