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SUMMARY:Computer-generated Cryptic Crossword Clues: exploring creative NLG
  - David Hardcastle\, The Open University
DTSTART:20080307T120000Z
DTEND:20080307T130000Z
UID:TALK10735@talks.cam.ac.uk
CONTACT:Johanna Geiss
DESCRIPTION:In this seminar I present some of the threads of research from
  my PhD\, in which I constructed a system called enigma which writes crypt
 ic crossword clues automatically.\n\n \n\nCryptic crossword clues are high
 ly unusual texts: they have two independent layers of meaning\, each of wh
 ich has a completely separate syntax and semantics. The starting goal for 
 enigma is a representation of the puzzle that will be hidden in the clue. 
 This puzzle can be rendered in very many different ways according to the c
 onventions of cryptic crossword writing\, but only a handful of these rend
 erings will also appear to be pieces of English prose\, a fundamental requ
 irement for any clue.\n\n \n\nFollowing the approach taken by human compil
 ers described in the expert literature on cryptic crossword compilation\, 
 and my own introspection\, enigma explores the search space bottom up usin
 g natural language semantic and selectional constraints as a pruning heuri
 stic.\n\n \n\nThe implementation takes the form of a chunk-based generator
  in which the grammar rules are encoded as syntactic constraints on the at
 tachments which are allowed to form between chunks. Each attachment is als
 o underwritten by semantic selectional constraints based on data sources m
 ined from corpora and related online resources using statistical technique
 s.\n\n \n\nEnigma was evaluated with a Turing-style test in which subjects
  were presented with computer-generated clues and clues from national news
 papers which had the same answer and had to decide which was which. On ave
 rage subjects identified the human-authored clues 75% of the time.
LOCATION:SW01 Computer Laboratory
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