1. MOE Key Laboratory for Transportation Complex Systems Theory and Technology, School of Traffic and Transportation, Beijing Jiaotong University, Beijing 100044, China
2. Basic Course Teaching Department, Jiangxi University of Science and Technology, Ganzhou, China
3. School of Information and Software Engineering, University of Electronic Science and Technology of China, Chengdu 610054, China
4. State Key Laboratory of Cryptology, P.O. Box 5159, Beijing 100878, China