[Chen, Sisi;Liu, Dan;Zheng, Jia;Hu, Xiaohua;Jiang, Xingpeng] Cent China Normal Univ, Sch Comp, Wuhan 430079, Hubei, Peoples R China.^[Chen, Pingtao] Univ Sci & Technol China, Sch Phys Sci, Hefei 230026, Anhui, Peoples R China.^[Hu, Xiaohua] Drexel Univ, Coll Comp & Informat, Philadelphia, PA 19104 USA.