School of Information Management, Beijing Information Science & Technology University, Beijing, China
School of Information Management, Beijing Information Science & Technology University, Beijing, China
School of Information Science & Technology, Beijing Institution of Technology, Beijing, China
Copyright © Junling Ren, Haiyan Kang, Zhifeng Ma 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.