Ideas for Google Summer of Code/Unsupervised weighting of automata

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[edit] Coding challenge

  • Install HFST
  • Install lttoolbox
  • Define an evaluation metric --- talk to your mentor
  • Perform a baseline experiment using a tagged corpus:
    • Select a language
    • Split the corpus into 90% training, 10% testing (or use existing test/train split)
    • Use the Apertium morphological analyser to analyse the test data
    • Rank the analyses produced using the training data
    • Compare this ranking to the default order from the transducer, and to a "random" ranking using your metric
    • Weight the analyser automaton based on the tagged corpus
    • Try surface weights, analysis weights, simple combination of the two

[edit] Hinweis

To calculate weights and stuff, just count tokens’ frequencies and corpus size, to prepare that for HFST automata you need to -log(freq) and get the stuff into hfst-strings2fst format (see man pages etc. for details)

To add weight to ane xisting analyser automaton, simple FSA operations with hfst should be enough: hfst-strings2fst, hfst-compose, hfst-union... you may need hfst-regexp2fst, hfst-minus or so to implement something for OOV items.

You can study an example here:


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