[1] Chinese Acad Sci, Acad Math & Syst Sci, Inst Computat Math & Sci Engn Comp, Beijing 100080, Peoples R China
[2] Beijing Broadcasting Inst, Dept Appl Math, Beijing 100024, Peoples R China
[3] Pohang Univ Sci & Technol, Combinatorial & Computat Math Ctr, Phoang 790784, South Korea