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A PDTB-styled end-to-end discourse parser

Published online by Cambridge University Press:  06 November 2012

ZIHENG LIN
Affiliation:
Department of Computer Science, National University of Singapore 13 Computing Drive, Singapore 117417 e-mail: linzihen@comp.nus.edu.sg, nght@comp.nus.edu.sg, kanmy@comp.nus.edu.sg SAP Research, SAP Asia Pte Ltd, 30 Pasir Panjang Road, Singapore 117440
HWEE TOU NG
Affiliation:
Department of Computer Science, National University of Singapore 13 Computing Drive, Singapore 117417 e-mail: linzihen@comp.nus.edu.sg, nght@comp.nus.edu.sg, kanmy@comp.nus.edu.sg
MIN-YEN KAN
Affiliation:
Department of Computer Science, National University of Singapore 13 Computing Drive, Singapore 117417 e-mail: linzihen@comp.nus.edu.sg, nght@comp.nus.edu.sg, kanmy@comp.nus.edu.sg

Abstract

Since the release of the large discourse-level annotation of the Penn Discourse Treebank (PDTB), research work has been carried out on certain subtasks of this annotation, such as disambiguating discourse connectives and classifying Explicit or Implicit relations. We see a need to construct a full parser on top of these subtasks and propose a way to evaluate the parser. In this work, we have designed and developed an end-to-end discourse parser-to-parse free texts in the PDTB style in a fully data-driven approach. The parser consists of multiple components joined in a sequential pipeline architecture, which includes a connective classifier, argument labeler, explicit classifier, non-explicit classifier, and attribution span labeler. Our trained parser first identifies all discourse and non-discourse relations, locates and labels their arguments, and then classifies the sense of the relation between each pair of arguments. For the identified relations, the parser also determines the attribution spans, if any, associated with them. We introduce novel approaches to locate and label arguments, and to identify attribution spans. We also significantly improve on the current state-of-the-art connective classifier. We propose and present a comprehensive evaluation from both component-wise and error-cascading perspectives, in which we illustrate how each component performs in isolation, as well as how the pipeline performs with errors propagated forward. The parser gives an overall system F1 score of 46.80 percent for partial matching utilizing gold standard parses, and 38.18 percent with full automation.

Type
Articles
Copyright
Copyright © Cambridge University Press 2012 

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References

Asher, N., and Lascarides, A. 2003. Logics of Conversation. Cambridge, UK: Cambridge University Press.Google Scholar
Baldridge, J., and Lascarides, A. 2005. Probabilistic head-driven parsing for discourse structure. In Proceedings of the Ninth Conference on Computational Natural Language Learning (CONLL 2005), Ann Arbor, Michigan, USA, pp. 96103.Google Scholar
Barzilay, R., and Lapata, M. 2008, March. Modeling local coherence: an entity-based approach. Computational Linguistics 34: 134.CrossRefGoogle Scholar
Carlson, L., Marcu, D., and Okurowski, M. E. 2001. Building a discourse-tagged corpus in the framework of Rhetorical Structure Theory. In Proceedings of the Second SIGdial Workshop on Discourse and Dialogue, Aalborg, Denmark, pp. 110.Google Scholar
Dinesh, N., Lee, A., Miltsakaki, E., Prasad, R., Joshi, A., and Webber, B. 2005. Attribution and the (non)-alignment of syntactic and discourse arguments of connectives. In Proceedings of the ACL Workshop on Frontiers in Corpus Annotation II: Pie in the Sky, Ann Arbor, MI, USA, pp. 2936.Google Scholar
duVerle, D., and Prendinger, H. 2009. A novel discourse parser based on support vector machine classification. In Proceedings of the Joint Conference of the 47th Annual Meeting of the ACL and the 4th International Joint Conference on Natural Language Processing of the AFNLP (ACL-IJCNLP 2009), Singapore, pp. 665673.Google Scholar
Elwell, R., and Baldridge, J. 2008. Discourse connective argument identification with connective specific rankers. In Proceedings of the IEEE International Conference on Semantic Computing (ICSC 2008), Santa Clara, CA, USA, pp. 198205.Google Scholar
Forbes, K., Miltsakaki, E., Prasad, R., Sarkar, A., Joshi, A., and Webber, B. 2003. D-LTAG system: discourse parsing with a lexicalized tree-adjoining grammar. Journal of Logic, Language and Information 12 (3): 261–79.Google Scholar
Ghosh, S., Johansson, R., Riccardi, G., and Tonelli, S. 2011. Shallow discourse parsing with conditional random fields. In Proceedings of the 5th International Joint Conference on Natural Language Processing (IJCNLP 2011), Chiang Mai, Thailand, pp. 1071–9 (November).Google Scholar
Grosz, Barbara J., and Sidner, Candace L. 1986, July. Attention, intentions, and the structure of discourse. Computational Linguistics 12 (3): 175204.Google Scholar
Grosz, Barbara J., Weinstein, S., and Joshi, Aravind K. 1995, June. Centering: a framework for modeling the local coherence of discourse. Computational Linguistics 21 (2): 203–25.Google Scholar
Halliday, Michael A. K., and Hasan, R. 1976. Cohesion in English. London: Longman.Google Scholar
Hobbs, Jerry R. 1985. On the coherence and structure of discourse. Technical Report CSLI-85-37, Center for the Study of Language and Information, Stanford University, Stanford, CA, USA.Google Scholar
Hobbs, Jerry R. 1990. Literature and cognition. In CSLI Lecture Notes Number 21. Stanford, CA, USA: CSLI.Google Scholar
Huong, Le T., Abeysinghe, G., and Huyck, C. 2004. Generating discourse structures for written texts. In Proceedings of the 20th International Conference on Computational Linguistics (COLING 2004), Geneva, Switzerland.Google Scholar
Knott, A. 1996. A Data-Driven Methodology for Motivating a Set of Coherence Relations. PhD thesis, Department of Artificial Intelligence, University of Edinburgh, Edinburgh, UK.Google Scholar
Knott, A., and Sanders, T. 1998. The classification of coherence relations and their linguistic markers: an exploration of two languages. Journal of Pragmatics 30 (2): 135–75.Google Scholar
Lascarides, A., and Asher, N. 1993. Temporal interpretation, discourse relations and commonsense entailment. Linguistics and Philosophy 16 (5): 437–93.Google Scholar
Lee, A., Prasad, R., Joshi, A., Dinesh, N., and Webber, B. 2006. Complexity of dependencies in discourse: are dependencies in discourse more complex than in syntax? In Proceedings of the 5th International Workshop on Treebanks and Linguistic Theories, Prague, Czech Republic.Google Scholar
Lin, Z., Kan, M.-Y., and Ng, H. T. 2009. Recognizing implicit discourse relations in the Penn Discourse Treebank. In Proceedings of the 2009 Conference on Empirical Methods in Natural Language Processing (EMNLP 2009), Singapore, pp. 343351.Google Scholar
Lin, Z., Liu, C., Ng, H. T., and Kan, M.-Y. 2012. Combining coherence models and machine translation evaluation metrics for summarization evaluation. In Proceedings of the 50th Annual Meeting of the Association for Computational Linguistics (ACL 2012), Jeju, Korea, July, pp. 10061014.Google Scholar
Lin, Z., Ng, H. T., and Kan, M.-Y. 2010. A PDTB-styled end-to-end discourse parser. Technical Report TRB8/10, School of Computing, National University of Singapore (August).Google Scholar
Lin, Z., Ng, H. T., and Kan, M.-Y. 2011. Automatically evaluating text coherence using discourse relations. In Proceedings of the 49th Annual Meeting of the Association for Computational Linguistics: Human Language Technologies (ACL-HLT 2011), Portland, OR, USA, June, pp. 9971006.Google Scholar
Mann, William C., and Thompson, Sandra A. 1988. Rhetorical Structure Theory: toward a functional theory of text organization. Text 8 (3): 243–81.Google Scholar
Marcu, D. 1997. The Rhetorical Parsing, Summarization, and Generation of Natural Language Texts. PhD thesis, University of Toronto, Ontario, Canada.Google Scholar
Marcus, Mitchell P., Marcinkiewicz, M. A., and Santorini, B. 1993. Building a large annotated corpus of English: the Penn Treebank. Computational Linguistics 19 (2): 313–30.Google Scholar
Miller, George A. 1995. Wordnet: a lexical database for English. Communications of the ACM 38 (11): 3941.Google Scholar
Miltsakaki, E., Dinesh, N., Prasad, R., Joshi, A., and Webber, B. 2005. Experiments on sense annotations and sense disambiguation of discourse connectives. In Proceedings of the Fourth Workshop on Treebanks and Linguistic Theories (TLT2005), Barcelona, Spain (December).Google Scholar
Miltsakaki, E., Prasad, R., Joshi, A., and Webber, B. 2004. The Penn Discourse Treebank. In Proceedings of the 4th International Conference on Language Resources and Evaluation (LREC 2004), Lisbon, Portugal.Google Scholar
PDTB-Group 2007. The Penn Discourse Treebank 2.0 Annotation Manual. Pennsylvania, PA, USA: PDTB Research Group.Google Scholar
Pitler, E., Louis, A., and Nenkova, A. 2009. Automatic sense prediction for implicit discourse relations in text. In Proceedings of the Joint Conference of the 47th Annual Meeting of the ACL and the 4th International Joint Conference on Natural Language Processing of the AFNLP (ACL-IJCNLP 2009), Singapore, pp. 683691.Google Scholar
Pitler, E., and Nenkova, A. 2009. Using syntax to disambiguate explicit discourse connectives in text. In Proceedings of the ACL-IJCNLP 2009 Conference Short Papers, Singapore, pp. 1316.Google Scholar
Pitler, E., Raghupathy, M., Mehta, H., Nenkova, A., Lee, A., and Joshi, A. 2008. Easily identifiable discourse relations. In Proceedings of the 22nd International Conference on Computational Linguistics (COLING 2008), Manchester, UK (Short papers).Google Scholar
Polanyi, L. 1988. A formal model of the structure of discourse. Journal of Pragmatics 12 (5–6): 601–38.Google Scholar
Polanyi, L., and Scha, R. 1984. A syntactic approach to discourse semantics. In Proceedings of the 10th International Conference on Computational Linguistics (COLING 1984), pp. 413–9. Stroudsburg, PA, USA.Google Scholar
Prasad, R., Dinesh, N., Lee, A., Miltsakaki, E., Robaldo, L., Joshi, A., and Webber, B. 2008. The Penn Discourse Treebank 2.0. In Proceedings of the 6th International Conference on Language Resources and Evaluation (LREC 2008), Marrakech, Morocco.Google Scholar
Prasad, R., Joshi, A., and Webber, B. 2010. Exploiting scope for shallow discourse parsing. In Proceedings of the Seventh International Conference on Language Resources and Evaluation (LREC-2010), Valletta, Malta, pp. 2076–83 (May).Google Scholar
Scha, R., and Polanyi, L. 1988. An augmented context-free grammar for discourse. In Proceedings of the 12th Conference on Computational Linguistics, pp. 573–7. Stroudsburg PA USA: Association for Computational Linguistics.Google Scholar
Skadhauge, P. R., and Hardt, D. 2005. Syntactic identification of attribution in the RST Treebank. In Proceedings of the Recent Advances in Natural Language Processing (RANLP 2005), Borovets, Bulgaria, pp. 5761.Google Scholar
Soricut, R., and Marcu, D. 2003. Sentence-level discourse parsing using syntactic and lexical information. In Proceedings of the Human Language Technology Conference of the North American Chapter of the Association for Computational Linguistics (HLT-NAACL 2003), Edmonton, Canada, pp. 149156.Google Scholar
Subba, R., and Di Eugenio, B. 2009. An effective discourse parser that uses rich linguistic information. In Proceedings of Human Language Technologies: The 2009 Annual Conference of the North American Chapter of the Association for Computational Linguistics (NAACL-HLT 2009), Boulder, Colorado (June). Stroudsburg, PA, USA, pp. 566574.Google Scholar
Wang, W. T., Su, J., and Tan, C. L. 2010. Kernel-based discourse relation recognition with temporal ordering information. In Proceedings of the 48th Annual Meeting of the Association for Computational Linguistics (ACL 2010), Uppsala, Sweden (July), pp. 710719.Google Scholar
Webber, B. 2004. D-LTAG: extending lexicalized TAG to discourse. Cognitive Science 28 (5): 751–79.Google Scholar
Webber, B., Egg, M., and Kordoni, V. 2011. Discourse structure and language technology. Natural Language Engineering 18 (4): 437490.CrossRefGoogle Scholar
Webber, B., and Joshi, A. 1998. Anchoring a lexicalized tree-adjoining grammar for discourse. In COLING-ACL Workshop on Discourse Relations and Discourse Markers, Montreal, Quebec, Canada, pp. 8692.Google Scholar
Wellner, B. 2009. Sequence Models and Ranking Methods for Discourse Parsing. Ph.D. thesis, Brandeis University, Waltham, MA, USA.Google Scholar
Wellner, B., and Pustejovsky, J. 2007. Automatically identifying the arguments of discourse connectives. In Proceedings of the 2007 Joint Conference on Empirical Methods in Natural Language Processing and Computational Natural Language Learning (EMNLP-CoNLL 2007), Prague, Czech Republic, pp. 92101.Google Scholar
Wellner, B., Pustejovsky, J., Havasi, C., Rumshisky, A., and Sauri, R. 2006. Classification of discourse coherence relations: an exploratory study using multiple knowledge sources. In Proceedings of the 7th SIGdial Workshop on Discourse and Dialogue, Sydney, Australia, pp. 117125.Google Scholar
Wolf, F., and Gibson, E. 2005. Representing discourse coherence: a corpus-based analysis. In Proceedings of the 20th International Conference on Computational Linguistics (COLING 2004), Morristown, NJ, USA, pp. 249288.Google Scholar
Zhou, Z.-M., Xu, Y., Niu, Z.-Y., Lan, M., Su, J., and Tan, C. L. 2010. Predicting discourse connectives for implicit discourse relation recognition. In Proceedings of the 23rd International Conference on Computational Linguistics (COLING 2010), Beijing, China, pp. 1507–14.Google Scholar