A Cross-Lingual Annotation Projection Approach for Relation Detection
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This document describes a method for cross-lingual annotation projection to detect relations in a target language without extensive annotation efforts. It projects relation annotations from a source language to a target language using word alignments from a parallel corpus. It introduces strategies to reduce noise from the projection process, including alignment filtering based on heuristics, alignment correction using a bilingual dictionary, and instance selection based on relation detection confidence scores. The method is evaluated on projecting relation annotations from English to Korean sentences.
A Cross-Lingual Annotation Projection Approach for Relation Detection
- 1. A CROSS-LINGUAL ANNOTATION PROJECTION APPROACH FOR RELATION DETECTION The 23rd International Conference on Computational Linguistics (COLING 2010) August 24th, 2010, Beijing Seokhwan Kim (POSTECH) Minwoo Jeong (Saarland University) Jonghoon Lee (POSTECH) Gary Geunbae Lee (POSTECH)
- 2. Contents • Introduction • Methods Cross-lingual Annotation Projection for Relation Detection Noise Reduction Strategies • Evaluation • Conclusion 2
- 3. Contents • Introduction • Methods Cross-lingual Annotation Projection for Relation Detection Noise Reduction Strategies • Evaluation • Conclusion 3
- 4. What’s Relation Detection? • Relation Extraction To identify semantic relations between a pair of entities ACE RDC • Relation Detection (RD) • Relation Categorization (RC) Owner-Of Jan Mullins, owner of Computer Recycler Incorporated said that … 4
- 5. What’s the Problem? • Many supervised machine learning approaches have been successfully applied to the RDC task (Kambhatla, 2004; Zhou et al., 2005; Zelenko et al., 2003; Culotta and Sorensen, 2004; Bunescu and Mooney, 2005; Zhang et al., 2006) • Datasets for relation detection Labeled corpora for supervised learning Available for only a few languages • English, Chinese, Arabic No resources for other languages • Korean 5
- 6. Contents • Introduction • Methods Cross-lingual Annotation Projection for Relation Detection Noise Reduction Strategies • Evaluation • Conclusion 6
- 7. Cross-lingual Annotation Projection • Goal To learn the relation detector without significant annotation efforts • Method To leverage parallel corpora to project the relation annotation on the source language LS to the target language LT 7
- 8. Cross-lingual Annotation Projection • Previous Work Part-of-speech tagging (Yarowsky and Ngai, 2001) Named-entity tagging (Yarowsky et al., 2001) Verb classification (Merlo et al., 2002) Dependency parsing (Hwa et al., 2005) Mention detection (Zitouni and Florian, 2008) Semantic role labeling (Pado and Lapata, 2009) • To the best of our knowledge, no work has reported on the RDC task 8
- 9. Overall Architecture Annotation Parallel Projection Corpus Sentences in Sentences in Ls Lt Preprocessing Preprocessing (POS Tagging, (POS Tagging, Parsing) Parsing) NER Word Alignment Relation Detection Projection Annotated Annotated Sentences in Sentences in Ls Lt 9
- 10. How to Reduce Noise? • Error Accumulation Numerous errors can be generated and accumulated through a procedure of annotation projection • Preprocessing for LS and LT • NER for LS • Relation Detection for LS • Word Alignment between LS and LT • Noise Reduction A key factor to improve the performance of annotation projection 10
- 11. How to Reduce Noise? • Noise Reduction Strategies (1) Alignment Filtering • Based on Heuristics A projection for an entity mention should be based on alignments between contiguous word sequences accepted rejected 11
- 12. How to Reduce Noise? • Noise Reduction Strategies (1) Alignment Filtering • Based on Heuristics A projection for an entity mention should be based on alignments between contiguous word sequences Both an entity mention in LS and its projection in LT should include at least one base noun phrase N N N N accepted rejected accepted rejected N 12
- 13. How to Reduce Noise? • Noise Reduction Strategies (1) Alignment Filtering • Based on Heuristics A projection for an entity mention should be based on alignments between contiguous word sequences Both an entity mention in LS and its projection in LT should include at least one base noun phrase The projected instance in LT should satisfy the clausal agreement with the original instance in LS N N N N accepted rejected accepted rejected rejected N 13
- 14. How to Reduce Noise? • Noise Reduction Strategies (2) Alignment Correction • Based on a bilingual dictionary for entity mentions Each entry of the dictionary is a pair of entity mention in LS and its translation or transliteration in LT FOR each entity ES in LS A B C D E F G RETRIEVE counterpart ET from DICT(E-T) SEEK ET from the sentence ST in LT IF matched THEN BCD - βγ MAKE new alignment ES-ET ENDIF ENDFOR α β γ δ ε δ ε corrected 14
- 15. How to Reduce Noise? • Noise Reduction Strategies (3) Assessment-based Instance Selection • Based on the reliability of a projected instances in LT Evaluated by the confidence score of monolingual relation detection for the original counterpart instance in LS Only instances with larger scores than threshold value θ are accepted conf = 0.9 conf = 0.6 θ = 0.7 accepted rejected 15
- 16. Contents • Introduction • Methods Cross-lingual Annotation Projection for Relation Detection Noise Reduction Strategies • Evaluation • Conclusion 16
- 17. Experimental Setup • Dataset English-Korean parallel corpus • 454,315 bi-sentence pairs in English and Korean • Aligned by GIZA++ Korean RDC corpus • Annotated following LDC guideline for ACE RDC corpus • 100 news documents in Korean 835 sentences 3,331 entity mentions 8,354 relation instances 17
- 18. Experimental Setup • Preprocessors English • Stanford Parser (Klein and Manning, 2003) • Stanford Named Entity Recognizer (Finkel et al., 2005) Korean • Korean POS Tagger (Lee et al., 2002) • MST Parser (R. McDonald et al., 2006) 18
- 19. Experimental Setup • Relation Detection for English Sentences Tree kernel-based SVM classifier • Training Dataset ACE 2003 corpus • 674 documents • 9,683 relation instances • Model Shortest path enclosed subtrees kernel (Zhang et al., 2006) • Implementation SVM-Light (Joachims, 1998) Tree Kernel Tools (Moschitti, 2006) 19
- 20. Experimental Setup • Relation Detection for Korean Sentences Tree kernel-based SVM classifier • Training Dataset Half of the Korean RDC corpus (baseline) Projected instances • Model Shortest path dependency kernel (Bunescu and Mooney, 2005) • Implementation SVM-Light (Joachims, 1998) Tree Kernel Tools (Moschitti, 2006) 20
- 21. Experimental Setup • Experimental Sets Combinations of noise reduction strategies • (S1: Heuristic, S2: Dictionary, S3: Assessment) 1. Baseline Trained with only half of the Korean RDC corpus 2. Baseline + Projections (no noise reduction) 3. Baseline + Projections (S1) 4. Baseline + Projections (S1 + S2) 5. Baseline + Projections (S3) 6. Baseline + Projections (S1 + S3) 7. Baseline + Projections (S1 + S2 + S3) 21
- 22. Experimental Setup • Evaluation On the second half of the Korean RDC corpus • The first half is for the baseline On true entity mentions with true chaining of coreference Evaluated by Precision/Recall/F-measure 22
- 23. Experimental Results no assessment with assessment Model P R F P R F baseline 60.5 20.4 30.5 - - - baseline + projection 22.5 6.5 10.0 29.1 13.2 18.2 Baseline + projection 51.4 15.5 23.8 56.1 22.9 32.5 (heuristics) Baseline + projection 55.3 19.4 28.7 59.8 26.7 36.9 (heuristics + dictionary) 23
- 24. Non-filtered Projects were Poor no assessment with assessment Model P R F P R F baseline 60.5 20.4 30.5 - - - baseline + projection 22.5 6.5 10.0 29.1 13.2 18.2 Baseline + projection 51.4 15.5 23.8 56.1 22.9 32.5 (heuristics) Baseline + projection 55.3 19.4 28.7 59.8 26.7 36.9 (heuristics + dictionary) 24
- 25. Heuristics Were Helpful no assessment with assessment Model P R F P R F baseline 60.5 20.4 30.5 - - - baseline + projection 22.5 6.5 10.0 29.1 13.2 18.2 Baseline + projection 51.4 15.5 23.8 56.1 22.9 32.5 (heuristics) Baseline + projection 55.3 19.4 28.7 59.8 26.7 36.9 (heuristics + dictionary) 25
- 26. Much Worse Than Baseline no assessment with assessment Model P R F P R F baseline 60.5 20.4 30.5 - - - baseline + projection 22.5 6.5 10.0 29.1 13.2 18.2 Baseline + projection 51.4 15.5 23.8 56.1 22.9 32.5 (heuristics) Baseline + projection 55.3 19.4 28.7 59.8 26.7 36.9 (heuristics + dictionary) 26
- 27. Dictionary Was Also Helpful no assessment with assessment Model P R F P R F baseline 60.5 20.4 30.5 - - - baseline + projection 22.5 6.5 10.0 29.1 13.2 18.2 Baseline + projection 51.4 15.5 23.8 56.1 22.9 32.5 (heuristics) Baseline + projection 55.3 19.4 28.7 59.8 26.7 36.9 (heuristics + dictionary) 27
- 28. Still Worse Than Baseline no assessment with assessment Model P R F P R F baseline 60.5 20.4 30.5 - - - baseline + projection 22.5 6.5 10.0 29.1 13.2 18.2 Baseline + projection 51.4 15.5 23.8 56.1 22.9 32.5 (heuristics) Baseline + projection 55.3 19.4 28.7 59.8 26.7 36.9 (heuristics + dictionary) 28
- 29. Assessment Boosted Performance no assessment with assessment Model P R F P R F baseline 60.5 20.4 30.5 - - - baseline + projection 22.5 6.5 10.0 29.1 13.2 18.2 Baseline + projection 51.4 15.5 23.8 56.1 22.9 32.5 (heuristics) Baseline + projection 55.3 19.4 28.7 59.8 26.7 36.9 (heuristics + dictionary) 29
- 30. Combined Strategies Achieved Better Performance Then Baseline no assessment with assessment Model P R F P R F baseline 60.5 20.4 30.5 - - - baseline + projection 22.5 6.5 10.0 29.1 13.2 18.2 Baseline + projection 51.4 15.5 23.8 56.1 22.9 32.5 (heuristics) Baseline + projection 55.3 19.4 28.7 59.8 26.7 36.9 (heuristics + dictionary) 30
- 31. Contents • Introduction • Methods Cross-lingual Annotation Projection for Relation Detection Noise Reduction Strategies • Evaluation • Conclusion 31
- 32. Conclusion • Summary A cross-lingual annotation projection for relation detection Three strategies for noise reduction Projected instances from an English-Korean parallel corpus helped to improve the performance of the task • with the noise reduction strategies • Future work A cross-lingual annotation projection for relation categorization More elaborate strategies for noise reduction to improve the projection performance for relation extraction 32
- 33. Q&A