[1] Univ Elect Sci & Technol China, Sch Management & Econ, Chengdu 610054, Sichuan, Peoples R China
[2] Univ Elect Sci & Technol China, Sch Comp Sci & Engn, Chengdu 610054, Sichuan, Peoples R China
[3] Univ Fribourg, Dept Phys, CH-1700 Fribourg, Switzerland
[4] Appalachian State Univ, Walker Coll Business, Boone, NC 28608 USA
[5] Univ Elect Sci & Technol China, Sch Informat & Software Engn, Chengdu 610054, Sichuan, Peoples R China