1. School of Electronic and Information Engineering, Beijing Jiaotong University, Beijing, China
2. School of Engineering, The University of British Columbia, Kelowna, Canada
3. College of Computer Science and Software Engineering, Shenzhen University, Shenzhen, China
4. School of Electrical Engineering and Telecommunications, University of New South Wales, Sydney, NSW, Australia
5. State Key Laboratory of Rail Traffic Control and Safety, Beijing Jiaotong University, Beijing, China