1. College of Computer Science and Electronic Engineering, Hunan University, Changsha, Hunan, China
2. College of Computer and Information Engineering, Central South University of Forestry and Technology, Changsha, China
3. Department of Product Integration, Chongqing Changxian Intelligent Technology Co., Ltd., Chongqing, China
4. College of Engineering, Mathematics and Physical Sciences, University of Exeter, England, U.K.