This dissertation studies the model, algorithm and application of several key research topics of information acquisition i.e. information crawling, information extraction, news event detection and tracking, cause-and-effect of news event etc.

• 基于这样一个前提，本文对Web信息获取若干关键问题，包括信息采集、信息抽取、事件探测和追踪、以及事件来龙去脉等方面，从模型、算法和应用三个层次上进行了深入细致的研究，主要贡献和创新点包括如下几个方面：