1. School of Electric Power Engineering, South China University of Technology, Guangzhou 510641, China
2. Hunan Institute of Science and Technology, School of Information Science and Engineering, Yueyang 414006, China
3. School of Computer Science and Engineering, Chongqing Three Gorges University, Wanzhou 404020, China
4. School of Automation, Guangdong University of Technology, Guangzhou 510006, China