1. School of Information Engineering, Nanchang University, Nanchang, China
2. Department of Informatics, King’s College London, London, U.K.
3. State Key Laboratory of Cognitive Neuroscience and Learning, Beijing Normal University, Beijing, China
4. State Key Laboratory of Robotics and Systems, Harbin Institute of Technology (Shenzhen), Shenzhen, China
5. School of Computing, University of Portsmouth, Portsmouth, U.K.