1. School of Computer Science, Beihang University, 12633 Beijing, China, 100083 (e-mail: beihangyc@buaa.edu.cn)
2. Computer Science, The University of Adelaide School of Computer Science, 549440 Adelaide, South Australia, Australia, 5005 (e-mail: pangguansong@gmail.com)
3. School of Computer Science and Engineering, Beihang University, 12633 Beijing, China, (e-mail: baixiao@buaa.edu.cn)
4. Jiangxi Normal University, School of Computer and Information Engineering, Nanchang, China, (e-mail: liuch@jxnu.edu.cn)
5. Chinese Academy of Sciences, Institute of Semiconductors Chinese Academy of Sciences, 71243 Beijing, Beijing, China, (e-mail: ninxin@semi.ac.cn)
6. National Institute of Informatics, The University of Tokyo, 13143 Bunkyo-ku, Tokyo, Japan, (e-mail: lin.gu@riken.jp)
7. School of Information and Communication Technology, Griffith University, 5723 Nathan, Queensland, Australia, (e-mail: jun.zhou@griffith.edu.au)