1. School of Computer and Software Engineering, Xihua University, Chengdu, Sichuan, China
2. School of Electrical Engineering and Electronic Information, Xihua University, Chengdu, Sichuan, China
3. School of Electrical and Electronic Engineering, The University of Adelaide, Adelaide, Australia
4. Research Group of Natural Computing, Department of Computer Science and Artificial Intelligence, University of Seville, Sevilla, Spain