1. State Key Laboratory of Earth Surface Processes and Resource Ecology, Beijing Normal University, 19 Xinjiekouwaidajie, Haidian District, Beijing 100875, China.
2. National ITS Center of Engineering and Technology, Research Institute of Highway, Ministry of Transport, No. 8 Xi Tu Cheng Road, Haidian District, Beijing 100088, China.
3. Centre for Computational Neuroscience and Robotics, University of Sussex, Brighton BN1 9QH, United Kingdom.