1. School of Computers, Guangdong University of Technology, Guangzhou, China
2. BNU-UIC Institute of Artificial Intelligence and Future Networks, Beijing Normal University (BNU Zhuhai), Zhuhai, Guangdong, China
3. Department of Computer Science, The University of Texas at Dallas, Richardson, TX, USA
4. College of Informatics, Huazhong Agricultural University, Wuhan, China