1. School of Computer and Information Engineering, Chuzhou University, Anhui, China
2. School of Computer Science, Nanjing University of Posts and Telecommunications, Nanjing, Jiangsu, China
3. School of Computer Science, Xidian University, Xi'an, Shaanxi, China
4. Kyungpook National University, Daegu, South Korea
5. School of Systems Information Science, Future University Hakodate, Hakodate, Hokkaido, Japan