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ACL17_Sakaguchi

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ACL 2017

Publié dans : Ingénierie
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ACL17_Sakaguchi

  1. 1. Error-repair Dependency Parsing for Ungrammatical Texts ACL 2017 Keisuke Sakaguchi, Matt Post, Benjamin Van Durme
  2. 2. Background & Motivation Parsing Noisy Text Learners Essay, Social Media, Speech Transcription 1 © http://riolindo.org/wp-content/uploads/2013/09/Reading.jpg, https://media.licdn.com/mpr/mpr/AAEAAQAAAAAAAA3BAAAAJGFhMDkxODNkLTBlZDQt NDE2Mi04NjAyLTYyZDM4OTk5ZjA0Yw.jpg, http://www.trbimg.com/img- 57918d4d/turbine/la-na-pol-donald-trump-convention-speech-transcript-20160721-snap
  3. 3. Background & Motivation Parsing Noisy Text Learners Essay, Web Texts, Speech Transcription 2 © http://riolindo.org/wp-content/uploads/2013/09/Reading.jpg, https://media.licdn.com/mpr/mpr/AAEAAQAAAAAAAA3BAAAAJGFhMDkxODNkLTBlZDQt NDE2Mi04NjAyLTYyZDM4OTk5ZjA0Yw.jpg, http://www.trbimg.com/img- 57918d4d/turbine/la-na-pol-donald-trump-convention-speech-transcript-20160721-snap
  4. 4. Background & Motivation Parsing Noisy Text Learners Essay, Web Texts, Speech Transcription e.g., (incorrect) I look in forward hear from you. (correct) I look forward to hearing from you. 3
  5. 5. Background & Motivation Parsing Noisy Text Learners Essay, Web Texts, Speech Transcription e.g., (incorrect) I look in forward hear from you. (correct) I look forward to hearing from you. Error correction ↓ Parsing Pipeline 4
  6. 6. Background & Motivation Parsing Noisy Text Learners Essay, Web Texts, Speech Transcription e.g., (incorrect) I look in forward hear from you. (correct) I look forward to hearing from you. Error correction ↓ Parsing Pipeline Error-repair parsing Joint training 5
  7. 7. Error-repair Dependency Parsing 1. Non-directional Easy-first parsing (Goldberg and Elhadad, 2010) 2. Three new actions to repair errors 6
  8. 8. Non-directional Easy-first Parsing 7 a brown fox jumped with joy a brown joywith joy fox a brown
  9. 9. Non-directional Easy-first Parsing 8 a brown fox jumped with joy a brown joywith joy fox a brown Pending List
  10. 10. Non-directional Easy-first Parsing a brown fox jumped with joy a brown joywith joy fox a brown 9 ATTACHRIGHT(𝑖) ATTACHLEFT(𝑖) Iteratively take actions until a complete tree is built.
  11. 11. Non-directional Easy-first Parsing a brown fox jumped with joy a brown joywith joy fox a brown 10
  12. 12. Non-directional Easy-first Parsing ATTACHRIGHT a brown fox jumped with joy a brown joywith joy fox a brown 11
  13. 13. Non-directional Easy-first Parsing a a fox jumped with joy a brown joywith joy fox a brown 12
  14. 14. Non-directional Easy-first Parsing ATTACHRIGHT a a fox jumped with joy a brown joywith joy fox a brown 13
  15. 15. Non-directional Easy-first Parsing a brown fox jumped with joy a brown joywith joy fox a brown 14
  16. 16. Non-directional Easy-first Parsing ATTACHLEFT a brown fox jumped with joy a brown joywith joy fox a brown 15
  17. 17. Non-directional Easy-first Parsing a brown fox jumped with joy a brown joywith joy fox a brown 16
  18. 18. Non-directional Easy-first Parsing ATTACHLEFT a brown fox jumped with joy a brown joywith joy fox a brown 17
  19. 19. Non-directional Easy-first Parsing a brown fox jumped with joy a brown joywith joy fox a brown 18
  20. 20. Non-directional Easy-first Parsing ATTACHRIGHT a brown fox jumped with joy a brown joywith joy fox a brown 19
  21. 21. Non-directional Easy-first Parsing a brown fox jumped with joy a brown joywith joy fox a brown 20
  22. 22. Non-directional Easy-first Parsing a brown fox jumped with joy a brown joywith joy fox a brown 21 root
  23. 23. Three new actions to repair errors SUBSTITUTE (𝑤%) replaces a token to another (grammatically more probable) token DELETE (𝑤%) removes an unnecessary token INSERT (𝑤%) inserts a new token at an index i. 22
  24. 24. Three new actions to repair errors I look in forward xhearx from you I youyou 23
  25. 25. I look in forward xhearx from you I youyou Three new actions to repair errors 24 ATTACHRIGHT ATTACHLEFT
  26. 26. I look in forward xhearx from you I youyou Three new actions to repair errors 25 SUBSTITUTE / DELETE / INSERT
  27. 27. ATTACHRIGHT I look in forward xhearx from you I youyou Three new actions to repair errors 26
  28. 28. I look in forward xhearx from you I youyou Three new actions to repair errors 27
  29. 29. ATTACHLEFT I look in forward xhearx from you I youyou Three new actions to repair errors 28
  30. 30. Three new actions to repair errors I look in forward xhearx from you I youyou 29
  31. 31. Three new actions to repair errors SUBSTITUTE I look in forward xhearx from you I youyou 30
  32. 32. Three new actions to repair errors I look in forward hearing from you I youyou 31
  33. 33. Three new actions to repair errors DELETE I look in forward hearing from you I youyou 32
  34. 34. Three new actions to repair errors I look forward hearing from from you I youyou 33
  35. 35. Three new actions to repair errors INSERT I look forward hearing from from you I youyou 34
  36. 36. Three new actions to repair errors I look forward to hearing from you I youyou 35
  37. 37. Three new actions to repair errors ATTACHLEFT I look forward to hearing from you I youyou 36
  38. 38. Three new actions to repair errors I look look to hearing from you I youyouI forward 37
  39. 39. We are ready to parse noisy texts … ? Wait!! The new actions may cause infinite loops. SUB à SUB à SUB à … INS à DEL à INS à DEL à ... 38
  40. 40. We are ready to parse noisy texts … ? Wait!! The new actions may cause infinite loops. SUB à SUB à SUB à … INS à DEL à INS à DEL à ... Heuristic constraints to avoid infinite loops 1. Limiting the number of new action operations 2. Substituted token cannot be substituted again 39
  41. 41. Training the parser 40 Model learns which action to take at each time step. structured perceptron + learning with exploration (Goldberg and Nivre, 2013) features: basic linguistic features (Goldberg and Elhadad 2010)
  42. 42. Training the parser 41 How to know which action is good (i.e., oracle, valid)? ATTACHLEFT & ATTACHRIGHT (Goldberg and Elhadad, 2010) 1. proposed edge is in the gold parse and 2. the child (to be attached) already has all its children SUBSTITUTE, DELETE, & INSERT 3. proposed action decreases the (word) edit distance to the gold (grammatical) sentence.
  43. 43. Experiments 42
  44. 44. Experiment 1 (simulated data) Dependency parsing on noisy Penn Treebank Errors injected similarly to Foster and Andersen (2009) 5 most frequent grammatical errors (CoNLL13) • Determiner (substitution, deletion, insertion) • Preposition (substitution, deletion, insertion) • Noun number (singular vs. plural) • Verb form (tense and aspect) • Subject verb agreement Eval: UAS by SParseval (Roark et al., 2006, Favre et al., 2010) Baseline: pipeline approach (error correction à parsing) 43
  45. 45. 44Result (Dependency: UAS)
  46. 46. Experiment 2 (real data) Grammaticality improvement on real ESL corpus Treebank of Learner English (Berzak et al., 2016) Grammaticality score (Heilman et al., 2014) Regression model with linguistic features 1 (incomprehensible) ~ 4 (perfect) 45
  47. 47. Result (Grammaticality on learner corpus) 46 * *
  48. 48. Summary Error-repair Dependency Parsing 1. Non-directional Easy-first Parsing 2. Three new actions to repair errors Experimental results 1. more robust against grammatical errors 2. improves grammaticality 47 I look in forward xhearx from you I youyou

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