[1] Commun Univ China, State Key Lab Media Convergence & Commun, Beijing 100024, Peoples R China
[2] Univ Chinese Acad Sci, Key Lab Computat Geodynam, Beijing 100049, Peoples R China
[3] Univ Alabama Huntsville, Dept Math Sci, Huntsville, AL 35899 USA
[4] Commun Univ China, Sch Sci, Beijing 100024, Peoples R China