1. School of Computer Science and TechnologyChina University of Mining and TechnologyXuzhou221116People's Republic of China
2. Key Laboratory of Intelligent Information ProcessingInstitute of Computing Technology, Chinese Academy of SciencesBeijing100190People's Republic of China
3. School of Mathematics and Computer ScienceAnhui Normal UniversityWuhu241003People's Republic of China
4. School of Computer and SoftwareNanjing University of Information Science & TechnologyNanjing210044People's Republic of China