Levit, M., Hakkani-Tür, D., Tur, G., & Gillick, D. (2009). IXIR: A statistical information distillation system. Computer Speech & Language, 23(4), 527-542.
The task of information distillation is to extract snippets from massive multilingual audio and textual document sources that are relevant for a given templated query. We present an approach that focuses on the sentence extraction phase of the distillation process. It selects document sentences with respect to their relevance to a query via statistical classification with support vector machines. The distinguishing contribution of the approach is a novel method to generate classification features. The features are extracted from charts, compilations of elements from various annotation layers, such as word transcriptions, syntactic and semantic parses, and information extraction (IE) annotations. We describe a procedure for creating charts from documents and queries, while paying special attention to query slots (free-text descriptions of names, organizations, topic, events and so on, around which templates are centered), and suggest various types of classification features that can be extracted from these charts. While observing a 30% relative improvement due to non-lexical annotation layers, we perform a detailed analysis of the contributions of each of these layers to classification performance.