1. Information Network Center, Anhui Jianzhu University, Hefei, PR China
2. School of Computing Engineering and Mathematics, Western Sydney University, Australia
3. School of Computer and Information, Hefei University of Technology, Hefei, PR China
4. Anhui Institute of Scientific and Technical Information, Hefei, PR China
5. School of Electronic and Information Engineering, Anhui Jianzhu University, Hefei, PR China
6. State Key Laboratory of Fire Science, University of Science and Technology of China, Hefei, PR China