1. School of Computer Science and Technology, Guangdong University of Technology, Guangzhou, China
2. Macao Polytechnic University, Macao, China
3. Department of Computer and Information Science, University of Macau, Macao, China
4. Department of Industrial and Systems Engineering, San José State University, San José, CA, USA
5. School of Information Engineering, Guangdong University of Technology, Guangzhou, China