1. School of Artificial Intelligence, the Engineering Research Center of Knowledge-Driven Human–Machine Intelligence, Jilin University, Changchun, China
2. Information System Department, WiSo Faculty, University of Cologne, Köln, Germany
3. School of Computer Science and Engineering, Nanyang Technological University, Singapore
4. College of Computer Science and Technology, Jilin University, Changchun, China
5. Department of Computer Science, University of Illinois at Chicago, Chicago, IL, USA