1. School of Computer, Electronics and Information, Guangxi University, Nanning 530004, P. R. China
2. Guangxi Colleges and Universities Key Laboratory of Parallel and Distributed Computing, Nanning 530004, P. R. China
3. Guangxi Normal University for Nationalities, Chongzuo 532200, P. R. China
4. Beihang University, Beijing Advanced Innovation Center for Big Data and Brain Computing (BDBC), Beijing, P. R. China