Discussion: Paraphrasing

Moderator: Francis Bond; Scribe: Michael Goodman

Objective

  • Share information on what is being done
    • parse and generate
      • problems with unknown words — can’t generate from MRS
      • can use Erik’s generation model (in batch mode)
    • monolingual translation

      • EnEn

        • mainly underspecification of => poss_rel => compound_or_prep

          • minutes of meeting/meeting’s minutes/meeting minutes/minutes of meeting’s
        • need to build a scoring model for the underspecified MRS
        • need a full MT model for transfer rules
      • What about lexical? meeting/transactions — massively larger TFS or external rules?
      • can everything be done by underspecification?
  • Applications
    • SMT training data
    • query expansion
    • normalization
    • relaxed input for MT
    • debugging
    • anything else?
  • How do we acquire paraphrase rules?
  • Discuss ways to make paraphrasing more robust
    • generation often freezes (host lisp running out of memory?)
    • generation debugging tools

Notes

Some existing discussions:

Overview

Objective: see what others are doing

Work has been done with parse + generate paraphrasing

  • Works for syntactic, sometimes lexical, alternations

Also have done work with a monolingual MT system (by Darren Appling)

  • Would like to do everything with underspecification
    • Perhaps Tim’s approach could work

How to acquire paraphrase rules?

  • Look for alternations in parallel corpora?

Making paraphrasing more robust.

Discussion

Lexical substitution:

  • Tim: Wordnet has not worked well in the past
    • syntactic constraints surrounding words are important
      • cannot just swap words

Tim: Are you doing paraphrasing for SMT on both sides?

  • Francis: Not yet, but Jacy may be capable now.

Bill: What’s difference between parse+generate and monolingual translation?

  • Francis: Parse+generate only paraphrases where there are no semantic differences.
    • Certain orderings are prohibited because of topicalization stati
    • Lexical substitution is limited to semantic hierarchies

Richard: Is there closure in the process, or can it be re-run?

  • Francis: Some recursive rules could do this, but not really beneficial.

Contractions are useful (eg. gonna -> going to)

Dan: Allow informal output?

  • Francis: only formal output.
    • some corrections have been used (eg. “go to the the bar” -> “go to the bar”)

Francis: The user/evaluator doesn’t need to be bilingual, and you only need one grammar to produce paraphrases.

Francis: An issue: don’t have the perfect unknown word handling mechanism.

  • eg. “I went to Barcelona and ate bacalao” (eg. don’t have “bacalao”)
    • Cannot generate from this.

Francis: Round trip efforts give a new perspective on your grammar.

Stephan: Can now get what is wanted (eg unknown words, normalization of preds, etc)

  • But have to add stuff to MRS construction code.
  • Would rather do lemmatization on the input.

Last update: 2012-02-16 by PeterAdolphs [edit]