1. School of Mechanical, Electronic and Control Engineering, Beijing Jiaotong University, Beijing, People's Republic of China
2. Department of Systems and Computer Engineering, Carleton University, Ottawa, ON, Canada
3. College of Mathematics and Physics, Bohai University, Jinzhou, People's Republic of China
4. School of Electronic and Information Engineering, University of Science and Technology Liaoning, Anshan, Liaoning, People's Republic of China