[Fan, Yetian;Wu, Wei] Dalian Univ Technol, Sch Math Sci, Dalian 116023, Peoples R China.^[Jiang, Xingpeng] Cent China Normal Univ, Sch Comp Sci, Wuhan 430079, Peoples R China.^[Hu, Xiaohua;Song, Bo;Ling, Yuan] Drexel Univ, Coll Comp & Informat, Philadelphia, PA 19104 USA.