| 1. |
- Calacean, Mihaela, et al.
(författare)
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A Data-Driven Dependency Parser for Romanian
- 2009
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Ingår i: Proceedings of the Seventh International Workshop on Treebanks and Linguistic Theories.. - 9789078328773 ; , s. 65-76
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Konferensbidrag (refereegranskat)
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| 2. |
- Eryigit, Gülsen, et al.
(författare)
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Dependency Parsing of Turkish
- 2008
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Ingår i: Computational linguistics - Association for Computational Linguistics (Print). - 0891-2017 .- 1530-9312. ; 34:3, s. 357-389
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Tidskriftsartikel (refereegranskat)abstract
- The suitability of different parsing methods for different languages is an important topic in syntactic parsing. Especially lesser-studied languages, typologically different from the languages for which methods have originally been developed, pose interesting challenges in this respect. This article presents an investigation of data-driven dependency parsing of Turkish, an agglutinative, free constituent order language that can be seen as the representative of a wider class of languages of similar type. Our investigations show that morphological structure plays an essential role in finding syntactic relations in such a language. In particular, we show that employing sublexical units called inflectional groups, rather than word forms, as the basic parsing units improves parsing accuracy. We test our claim on two different parsing methods, one based on a probabilistic model with beam search and the other based on discriminative classifiers and a deterministic parsing strategy, and show that the usefulness of sublexical units holds regardless of the parsing method. We examine the impact of morphological and lexical information in detail and show that, properly used, this kind of information can improve parsing accuracy substantially. Applying the techniques presented in this article, we achieve the highest reported accuracy for parsing the Turkish Treebank.
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| 3. |
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| 4. |
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| 5. |
- Hall, Johan, et al.
(författare)
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Parsing Discontinuous Phrase Structure with Grammatical Functions
- 2008
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Ingår i: Advances in Natural Language Processing. - Berlin / Heidelberg : Springer. - 9783540852865 ; , s. 169-180
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Konferensbidrag (refereegranskat)abstract
- This paper presents a novel technique for parsing discontinuous phrase structure representations, labeled with both phrase labels and grammatical functions. Phrase structure representations are transformed into dependency representations with complex edge labels, which makes it possible to induce a dependency parser model that recovers the phrase structure with both phrase labels and grammatical functions. We perform an evaluation on the German TIGER treebank and the Swedish Talbanken05 treebank and report competitive results for both data sets.
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| 6. |
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| 7. |
- Megyesi, Beáta, et al.
(författare)
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Swedish-Turkish Parallel Treebank
- 2008
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Ingår i: Proceedings of the Sixth International Conference on Language Resources and Evaluation (LREC). - : ELRA, Paris. ; , s. 470-473
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Konferensbidrag (refereegranskat)
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| 8. |
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| 9. |
- Nivre, Joakim, 1962-
(författare)
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Algorithms for Deterministic Incremental Dependency Parsing
- 2008
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Ingår i: Computational linguistics - Association for Computational Linguistics (Print). - 0891-2017 .- 1530-9312. ; 34:4, s. 513-553
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Tidskriftsartikel (refereegranskat)abstract
- Parsing algorithms that process the input from left to right and construct a single derivation have often been considered inadequate for natural language parsing because of the massive ambiguity typically found in natural language grammars. Nevertheless, it has been shown that such algorithms, combined with treebank-induced classifiers, can be used to build highly accurate disambiguating parsers, in particular for dependency-based syntactic representations. In this article, we first present a general framework for describing and analyzing algorithms for deterministic incremental dependency parsing, formalized as transition systems. We then describe and analyze two families of such algorithms: stack-based and list-based algorithms. In the former family, which is restricted to projective dependency structures, we describe an arc-eager and an arc-standard variant; in the latter family, we present a projective and a non-projective variant. For each of the four algorithms, we give proofs of correctness and complexity. In addition, we perform an experimental evaluation of all algorithms in combination with SVM classifiers for predicting the next parsing action, using data from thirteen languages. We show that all four algorithms give competitive accuracy, although the non-projective list-based algorithm generally outperforms the projective algorithms for languages with a non-negligible proportion of non-projective constructions. However, the projective algorithms often produce comparable results when combined with the technique known as pseudo-projective parsing. The linear time complexity of the stack-based algorithms gives them an advantage with respect to efficiency both in learning and in parsing, but the projective list-based algorithm turns out to be equally efficient in practice. Moreover, when the projective algorithms are used to implement pseudo-projective parsing, they sometimes become less efficient in parsing (but not in learning) than the non-projective list-based algorithm. Although most of the algorithms have been partially described in the literature before, this is the first comprehensive analysis and evaluation of the algorithms within a unified framework.
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| 10. |
- Nivre, Joakim, 1962-, et al.
(författare)
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An Improved Oracle for Dependency Parsing with Online Reordering
- 2009
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Ingår i: Proceedings of the 11th International Conference on Parsing Technologies (IWPT). - Stroudsburg, PA, USA : Association for Computational Linguistics. ; , s. 73-76
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Konferensbidrag (refereegranskat)abstract
- We present an improved training strategyfor dependency parsers that use online re-ordering to handle non-projective trees.The new strategy improves both efficiency and accuracy by reducing the number of swap operations performed on non-projective trees by up to 80%. We present state-of-the-art results for five languages with the best ever reported results for Czech.
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| 11. |
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| 12. |
- Nivre, Joakim, 1962-, et al.
(författare)
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Dependency Parsing
- 2009
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Bok (övrigt vetenskapligt/konstnärligt)abstract
- Dependency-based methods for syntactic parsing have become increasingly popular in natural lan- guage processing in recent years. This book gives a thorough introduction to the methods that are most widely used today. After an introduction to dependency grammar and dependency parsing, followed by a formal characterization of the dependency parsing problem, the book sur veys the three major classes of parsing models that are in current use: transition-based, graph-based, and grammar-based models. It continues with a chapter on evaluation and one on the comparison of dif- ferent methods, and it closes with a few words on current trends and future prospects of dependency parsing. The book presupposes a knowledge of basic concepts in linguistics and computer science, as well as some knowledge of parsing methods for constituency-based representations.
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| 13. |
- Nivre, Joakim, 1962-, et al.
(författare)
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Integrating Graph-Based and Transition-Based Dependency Parsers
- 2008
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Ingår i: Proceedings of the 46th Annual Meeting of the Association for Computational Linguistics: Human Language Technologies (ACL-08: HLT). - Stroudsburg, PA : Association for Computational Linguistics (ACL). - 9781932432046 ; , s. 950-958
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Konferensbidrag (refereegranskat)abstract
- Previous studies of data-driven dependency parsing have shown that the distribution of parsing errors are correlated with theoretical properties of the models used for learning and inference. In this paper, we show how these results can be exploited to improve parsing accuracy by integrating a graph-based and a transition-based model. By letting one model generate features for the other, we consistently improve accuracy for both models, resulting in a significant improvement of the state of the art when evaluated on data sets from the CoNLL-X shared task.
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| 14. |
- Nivre, Joakim, 1962-
(författare)
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Non-Projective Dependency Parsing in Expected Linear Time
- 2009
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Ingår i: 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. - : Association for Computational Linguistics. - 9781932432459 ; , s. 351-359
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Konferensbidrag (refereegranskat)
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| 15. |
- Nivre, Joakim, 1962-
(författare)
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Parsing Indian Languages with MaltParser
- 2009
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Ingår i: Proceedings of the ICON09 NLP Tools Contest: Indian Language Dependency Parsing. ; , s. 12-18
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Konferensbidrag (refereegranskat)
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| 16. |
- Nivre, Joakim, 1962-, et al.
(författare)
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Parsing the SynTagRus Treebank of Russian
- 2008
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Ingår i: Proceedings of the 22nd International Conference on Computational Linguistics (Coling 2008). - 9781905593446 ; , s. 641-648
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Konferensbidrag (refereegranskat)abstract
- We present the first results on parsing the SYNTAGRUS treebank of Russian with a data-driven dependency parser, achieving a labeled attachment score of over 82% and an unlabeled attachment score of 89%. A feature analysis shows that high parsing accuracy is crucially dependent on the use of both lexical and morphological features. We conjecture that the latter result can be generalized to richly inflected languages in general, provided that sufficient amounts of training data are available.
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| 17. |
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| 18. |
- Nivre, Joakim, 1962-
(författare)
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Sorting Out Dependency Parsing
- 2008
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Ingår i: Advances in Natural Language Processing, Proceedings. - Berlin / Heidelberg : Springer. - 9783540852865 ; , s. 16-27
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Konferensbidrag (refereegranskat)abstract
- This paper explores the idea that non-projective dependency parsing can be conceived as the outcome of two interleaved processes, one that sorts the words of a sentence into a canonical order, and one that performs strictly projective dependency parsing on the sorted input. Based on this idea, a parsing algorithm is constructed by combining an online sorting algorithm with an arc-standard transition system for projective dependency parsing.
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| 19. |
- Nivre, Joakim, 1962-
(författare)
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Treebanks
- 2008
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Ingår i: Corpus Linguistics. - : Mouton de Gruyter. ; , s. 225-241
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Bokkapitel (refereegranskat)
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| 20. |
- Nivre, Joakim, 1962-
(författare)
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Treebanks
- 2008
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Ingår i: Corpus Linguistics. - Berlin : Mouton de Gruyter. - 9783110180435 ; , s. 225-241
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 21. |
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Resourceful Language Technology : Festschrift in Honor of Anna Sågvall Hein
- 2008
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Samlingsverk (redaktörskap) (övrigt vetenskapligt/konstnärligt)abstract
- As the first holder of the first chair in computational linguistics in Sweden, Anna Sågvall Hein has played a central role in the development of computational linguistics and language technology both in Sweden and on the international scene. Besides her valuable contributions to research, which include work on machine translation, syntactic parsing, grammar checking, word prediction, and corpus linguistics, she has been instrumental in establishing a national graduate school in language technology as well as an undergraduate program in language technology at Uppsala University. It is with great pleasure that we present her with this Festschrift to honor her lasting contributions to the field and to commemorate her retirement from the chair in computational linguistics at Uppsala University. The contributions to the Festschrift come from Anna’s friends and colleagues around the world and deal with many of the topics that are dear to her heart. A common theme in many of the articles, as well as in Anna’s own scientific work, is the design, development and use of adequate language technology resources, epitomized in the title Resourceful Language Technology.
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| 22. |
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