1. Key Laboratory of Dependable Service Computing in Cyber Physical Society, Ministry of Education, and the College of Computer Science, Chongqing University, Chongqing, China
2. College of Information Science and Technology, Jinan University, Guangzhou, China
3. School of Electronics Engineering and Computer Science, Peking University, Beijing, China
4. CRSC Research Laboratory for Smart City, China Railway Signal and Communication Company Ltd. (CRSC), Beijing, China
5. Department of Computer Science, Tsinghua University, Beijing, China