1. School of Computer Science, Civil Aviation Flight University of China, Guanghan, China
2. Chongqing Institute of Green and Intelligent Technology and the Chongqing School, University of Chinese Academy of Sciences, Chongqing, China
3. Faculty of Information Technology and Electrical Engineering, University of Oulu, Oulu, Finland
4. College of Computer and Information Science, Southwest University, Chongqing, China