1. School of Automation Science and Engineering, South China University of Technology, Guangzhou, China + Center for Brain Computer Interfaces and Brain Information Processing, South China University of Technology, Guangzhou, China
2. School of Automation Science and Engineering, South China University of Technology, Guangzhou, China + Center for Brain Computer Interfaces and Brain Information Processing, South China University of Technology, Guangzhou, China + School of Computer Science and Engineering, Nanyang Technological University, Singapore
3. School of Automation Science and Engineering, South China University of Technology, Guangzhou, China + Center for Brain Computer Interfaces and Brain Information Processing, South China University of Technology, Guangzhou, China + School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, USA
4. School of Automation Science and Engineering, South China University of Technology, Guangzhou, China