1. School of Information and Control Engineering, China University of Mining and Technology, Xuzhou, China
2. School of Computer Science and Informatics, Institute of Artificial Intelligence, De Montfort University, The Gateway, Leicester, U.K.
3. Electromechanical and Information Engineering, China University of Mining and Technology (Beijing), Beijing, China
4. School of Information Science and Technology, Qingdao University of Science and Technology, Qingdao, China