1. School of Automation, Guangdong Polytechnic Normal University, Guangzhou, China
2. Department of Information Technology and Electrical Engineering, University of Oulu, Oulu, Finland
3. School of Automation, Guangdong University of Petrochemical Technology, Maoming, China
4. Guangdong Provincial Key Laboratory of Computational Intelligence and Cyberspace Information, the School of Computer Science and Engineering, South China University of Technology, Guangzhou, China