[1] Nanjing Univ Posts & Telecommun, Sch Comp, Nanjing 210003, Jiangsu, Peoples R China
[2] Chinese Acad Sci, Inst Informat Engn, Beijing 100093, Peoples R China
[3] Coll William & Mary, Dept Comp Sci, Williamsburg, VA 23187 USA
[4] Wayne State Univ, Dept Comp Sci, Detroit, MI 48202 USA
[5] Univ Sci & Technol China, Sch Comp Sci & Technol, Hefei 230022, Peoples R China