1. School of Computer Science and Technology Huaqiao University Xiamen 361021 P. R. China
2. Department of Electrical and Computer Engineering New Jersey Institute of Technology Newark NJ 07102 USA
3. Institute of Systems Engineering Macau University of Science and Technology Taipa Macau
4. School of Electro‐Mechanical Engineering Xidian University Xi'an 710071 P. R. China
5. School of Computer and Software Engineering Xihua University Chengdu 610039 P. R. China