Toward a document model for question answering systems

Abstract

The problem of acquiring valuable information from the large amounts available today in electronic media requires automated mechanisms more natural and efficient than those already existing. The trend in the evolu-tion of information retrieval systems goes toward systems capable of answering specific questions formulated by the user in her/his language. The expected an-swers from such systems are short and accurate sentences, instead of large document lists. On the other hand, the state of the art of these systems is fo-cused -mainly- in the resolution of factual questions, whose answers are named entities (dates, quantities, proper nouns, etc). This paper proposes a model to represent source documents that are then used by question answering systems. The model is based on a representation of a document as a set of named entities (NEs) and their local lexical context. These NEs are extracted and classified automatically by an off-line process. The entities are then taken as instance concepts in an upper ontology and stored as a set of DAML+OIL resources which could be used later by question answering engines. The paper presents a case of study with a news collection in Spanish and some preliminary results.