1. School of Computer Science and Technology, Guangdong University of Technology, Guangzhou, China
2. School of Information Science and Technology, Guangdong University of Foreign Studies, Guangzhou, China
3. Faculty of Applied Sciences, Macau Polytechnic University, Macau, China
4. Guangzhou Quwan Network Technology Company Ltd., Guangzhou, China
5. Department of Computer and Information Science, University of Macau, Macau, China