1. Innovative Information Industry Research Center, Shenzhen Graduate School, Harbin Institute of Technology, Shenzhen 518055, China
2. College of Information Science and Engineering, Fujian University of Technology, Fuzhou 350118, China
3. Department of Computer Science, VSB Technical University of Ostrava, 70833 Ostrava, Czech Republic
4. Department of Computer Science and Information Engineering, Cheng Shiu University, Kaohsiung 83347, Taiwan