1. Key Laboratory of Big Data & Artificial Intelligence in Transportation (Beijing Jiaotong University), Ministry of Education, Beijing, China and Engineering Research Center of Integration and Application of Digital Learning Technology, Ministry of Education, Beijing, China
2. Tangshan Research Institute of Beijing Jiaotong University, Beijing, China and Engineering Research Center of Integration and Application of Digital Learning Technology, Ministry of Education, Beijing, China
3. School of Computer Science and Technology, Beijing Jiaotong University, Beijing, China
4. College of Science and Technology, Beijing Open University, Beijing, China
5. Information Systems Technology and Design Pillar, Singapore University of Technology and Design, Singapore, Singapore