Using Answer Retrieval Patterns to Answer Portuguese Questions

Esfinge is a general domain Portuguese question answering system which has been participating at QA@CLEF since 2004. It uses the information available in the "official" document collections used in QA@CLEF (newspaper text and Wikipedia) and information from the Web as an additional resource when searching for answers. Where it regards the use of external tools, Esfinge uses a syntactic analyzer, a morphological analyzer and a named entity recognizer. This year an alternative approach to retrieve answers was tested: whereas in previous years, search patterns were used to retrieve relevant documents, this year a new type of search patterns was also used to extract the answers themselves. We also evaluated the second and third best answers returned by Esfinge. This evaluation showed that when Esfinge answers correctly a question, it does so usually with its first answer. Furthermore, the experiments revealed that the answer retrieval patterns created for this participation improve the results, but only for definition questions.