Department;
of;
Computer;
Science;
and;
Technology,;
State;
Key;
Laboratoryof;
Intelligent;
Technology;
and;
Systems,;
Tsinghua;
National;
Laboratoryfor;
Information;
Science;
and;
Technology,;
Tsinghua;
University,;
Beijing100084,;
China;
先验知识; 提取方法; 关键字; 图形; 监督方法; 拓扑结构; 实验; 文档;