1. Complex System and Computational Intelligence Laboratory, Taiyuan University of Science and Technology, Taiyuan, Shanxi 030024, China
2. State Key Laboratory for Novel Software Technology, Nanjing University, Nanjing 210093, China
3. West Texas A&M University, Canyon, TX 79016, USA
4. Western Norway Research Institute, 6851 Sogndal, Norway
5. School of Science and Technology, Middlesex University, London NW4 4BT, UK