[1] Hefei Univ Technol, Sch Comp Sci & Informat Engn, Hefei 230009, Peoples R China
[2] Tsinghua Univ, Dept Comp Sci & Technol, Beijing 100084, Peoples R China
[3] Chinese Acad Sci, Inst Automat, Beijing 100190, Peoples R China
[4] Nanyang Technol Univ, Sch Comp Sci & Engn, Singapore 639798, Singapore