1. Department of Industrial Engineering and Management, School of Mechanical Engineering, Shanghai Jiao Tong University, Shanghai, China
2. Faculty of Information Technology, Beijing Key Laboratory of Computational Intelligence and Intelligent System, Engineering Research Center of Digital Community, Ministry of Education, and Beijing Laboratory for Urban Mass Transit, Beijing University of Technology, Beijing, China
3. Department of Industrial and Systems Engineering, University of Wisconsin-Madison, Madison, WI, USA
4. Department of Industrial Engineering and Management, Peking University, Beijing, China