1. Department of Computer Science, Hong Kong Baptist University, Hong Kong, People’s Republic of China
2. Department of Computer Science, China Jiliang University, Hangzhou, People’s Republic of China
3. Department of Mathematics, Hong Kong Baptist University, Hong Kong, People’s Republic of China
4. Key Laboratory of Opto-electronic Technology and Intelligent Control of the Ministry of Education, Lanzhou Jiaotong University, Lanzhou, People’s Republic of China