LIU Xiao-hua1,2, WEI Fu-ru2, DUAN Ya-juan3, ZHOU Ming2
1. School of Computer Science and Technology, Harbin Institute of Technology, Harbin 150001, Heilongjiang, China;
2. Microsoft Research Asia, Beijing 100080, China; 3. School of Computer Science and Technology,
University of Science and Technology of China, Hefei 230026, Anhui, China