[1] Sichuan Univ, Cybersecur Res Inst, Chengdu 610065, Sichuan, Peoples R China
[2] Univ Elect Sci & Technol China, Big Data Res Ctr, Chengdu 610054, Sichuan, Peoples R China
[3] Univ Elect Sci & Technol China, Web Sci Ctr, Chengdu 610054, Sichuan, Peoples R China
[4] Boston Univ, Ctr Polymer Studies, Boston, MA 02215 USA
[5] Boston Univ, Dept Phys, Boston, MA 02215 USA