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Unsupervised Construction of Large Paraphrase Corpora: Exploiting Massively Parallel News Sources

Written for the Research library (claude-opus-5-5) from the paper text, in our own words: the license "CC BY-NC-SA 3.0 (ACL Anthology, before 2016)" does not allow redistributing the text itself. Original — aclanthology.org/C04-1051.pdf

Summary

The paper tackles a shortage of large, broad-domain collections of sentence-level paraphrase pairs that could be used to train statistical machine translation (SMT) style models within a single language. The authors gathered 11,162 topically and temporally clustered news clusters (177,095 articles from thousands of web sources over eight months) and compared two unsupervised ways of pairing sentences within each cluster. The first keeps pairs with a small Levenshtein distance (the L12 corpus). The second relies on the journalistic habit of opening articles with summary sentences, so it pairs the first two sentences of articles in the same cluster, after light lexical and length filtering (the F2 corpus). They evaluated both corpora by training word alignment models and measuring alignment error rate (AER), and they also hand-analysed the types of paraphrase each corpus contains. L12 proved cleaner and easier to align. F2, although noisier, preserved far more of the complex rewordings and reorderings that make paraphrase interesting. This suggests that edit-distance extraction trades linguistic richness for precision.

Key points

  • Corpus sizes: L12 has about 139K sentence pairs, with a maximum Levenshtein distance of 12 and a mean distance of 5.17. F2 has about 214K pairs. In a human-rated sample of 448 F2 pairs, 26.3% were full paraphrases and 33.7% were partial paraphrases.
  • F2 filters: each pair must share at least 3 words of 4 or more characters, and the shorter sentence must be at least half as long as the longer one.
  • Alignment results: L12-trained alignment reached 11.58% AER on a test set extracted the same way. On F2-style test data, the two training sets performed similarly, at 13.2% (L12) and 14.7% (F2).
  • Manual analysis: the authors annotated 100 pairs per corpus. In F2, phrasal alternations were over 4× more frequent and reorderings over 20× more frequent than in L12, although F2 also contained more elaborations, meaning it is less parallel.
  • Future work: the authors propose a paraphrase classifier combining edit distance, clustering, discourse, sentence-length and synonymy features. They intend to apply SMT methods to paraphrase recognition and generation.

Our summary of the paper, in our own words — not its text. The work belongs to its authors; read it at the links above.

Fields: Machine translation

Topics: Machine translation

Cited by

292 papers of our library cite it (of the 140673 whose bibliographies we read); 22 of them have a page here, 270 not yet.

Cite

The paper itself, not this page. BibTeX from the library's record of the work.

@inproceedings{dolan2004unsupervised,
  title = {{Unsupervised Construction of Large Paraphrase Corpora: Exploiting Massively Parallel News Sources}},
  author = {Dolan, Bill and Quirk, Chris and Brockett, Chris},
  booktitle = {COLING 2004: Proceedings of the 20th International Conference on Computational Linguistics},
  year = {2004},
  url = {https://aclanthology.org/C04-1051/}
}

References

11 references, 2 of them with a card of ours. ↗ leads to the work, «find» searches for one we have no id for yet.

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