1. School of Automation, Nanjing University of Science and Technology, Nanjing, China
2. Department of Computer Science, Brunel University London, Uxbridge, U.K.
3. Department of Automation, Tsinghua University, Beijing, China
4. School of Computing and Engineering, University of Huddersfield, Huddersfield, U.K.
5. Institute of Advanced Technology, Nanjing University of Posts and Telecommunications, Nanjing, China