[1] Peking Univ, Sch EE&CS, Dept Comp Sci & Technol, Beijing 100871, Peoples R China
[2] PengCheng Lab, Artificial Intelligence Res Ctr, Shenzhen 518066, Peoples R China
[3] Univ Amsterdam, Informat Inst, NL-94323 Amsterdam, Netherlands
[4] Microsoft Res Asia, Beijing 100080, Peoples R China
[5] AT&T Labs Res, Middletown, NJ 07748 USA
[6] Univ Augsburg, Comp Sci Dept, D-86159 Augsburg, Germany
[7] Carl von Ossietzky Univ Oldenburg, Dept Comp Sci, D-26121 Oldenburg, Germany