The system takes a natural-language query as input and produces a list of answers ranked in order of confidence. According to Language Techonology World where a project in Answer Extraction is developed by Rolf Schwitter, Michael Hess, Rachel Fournier, Diego Mollá-Aliod, Gerold Schneider, ExtrAns is one of the most developed programs in Answer Extraction.
ExtrAns is a system that finds answers to questions about (the Solaris variety of) UNIX in the on-line system documentation, the manpages. The questions may be phrased in ordinary English rather than in some formal query language. The answers are the sentence(s) of the manpages containing direct answers to the question (if there are any), complete with clickable links into the full manpages containing them.
The search procedure uses a proof algorithm of the user query over the Horn clause representation of the minimal logical forms. Remaining ambiguities in the retrieved sentences are dealt with by graded highlighting.
- ExtrAns. In Zurich university. Retrieved 30th March 2009, 12:15. From http://www.ifi.uzh.ch/arvo/cl/extrans/
- Answer Extraction by Steven Abney Michael Collins Amit Singhal. In Vinartus Retrieved 30th March 2009, 12:35. From http://www.vinartus.net/spa/99f.pdf
- Extrans, an answer extraction system by Mots Clefs Keywords, Diego Moll, Diego Moll, Rolf Schwitter, Rolf Schwitter, Michael Hess, Michael Hess, Rachel Fournier, Rachel Fournier. In CtiteSeer. Retrieved 30th march 2009, 12:45. From http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.43.3993
- Off-line Answer Extraction for Dutch Question Answering (December 17th 2004) In Odur by Jori Mur. retrieved 30th March 2009, 12:50. From http://odur.let.rug.nl/~gosse/Imix/clin04_mur.pdf