School of Information Science and Engineering, Hebei North University, Zhangjiakou, China
School of Information Science and Engineering, Hebei North University, Zhangjiakou, China
School of Information Science and Engineering, Hebei North University, Zhangjiakou, China
Copyright © Xinghua Sun, Li Hao, Xiao Zhang et al. This is
an open access article distributed under the Creative Commons Attribution
License, which permits unrestricted use, distribution, and reproduction in any
medium, provided the original work is properly cited.