--- title: "Comparison of Classification and Ranking — Ngụy 2009" description: "The paper addresses resolving third-person personal and possessive pronouns in Czech, including zero (pro-dropped) pronouns that are reconstructed in the…" authors: ["Giang Linh Ngụy", "Václav Novák", "Zdeněk Žabokrtský"] year: 2009 venue: "Proceedings of the SIGDIAL 2009 Conference" source: "https://aclanthology.org/W09-3939/" licence: "CC BY-NC-SA 3.0 (ACL Anthology, before 2016)" licence_url: "https://creativecommons.org/licenses/by-nc-sa/3.0/" summary_licence: "Elamur Cosmic License" canonical: "https://research.elamur.ai/free/papers/y-2009-comparison-classification-ranking-approaches-pronominal/" --- [Elamur Research](https://md.research.elamur.ai/) · [this page in HTML](https://research.elamur.ai/free/papers/y-2009-comparison-classification-ranking-approaches-pronominal/) [home](https://md.research.elamur.ai/) / [papers](https://md.research.elamur.ai/free/papers/) / [2009](https://md.research.elamur.ai/free/papers/2009/) / Comparison of Classification and Ranking Approaches to Pronominal Anaphora Resolution in Czech # Comparison of Classification and Ranking Approaches to Pronominal Anaphora Resolution in Czech **Authors:** Giang Linh Ngụy, Václav Novák, [Zdeněk Žabokrtský](https://md.research.elamur.ai/free/authors/zdenek-zabokrtsku/) · **Year:** 2009 · **Venue:** Proceedings of the SIGDIAL 2009 Conference · **Licence:** [CC BY-NC-SA 3.0 (ACL Anthology, before 2016)](https://creativecommons.org/licenses/by-nc-sa/3.0/) **Links:** [Publisher's page](https://aclanthology.org/W09-3939/) · [PDF](https://aclanthology.org/W09-3939.pdf) · [OpenAlex](https://openalex.org/W87155745) **Citations:** 12 citations (openalex-snapshot · 2026-10-14) · [4](#cited-by) in our library, of the 140673 papers whose bibliographies we read ## Summary The paper addresses resolving third-person personal and possessive pronouns in Czech, including zero (pro-dropped) pronouns that are reconstructed in the deep-syntactic layer. Using the manually annotated textual coreference in the Prague Dependency Treebank 2.0, the authors build two supervised systems that share the same preprocessing and a rich feature set. That feature set draws on all annotation levels, on ideas from Lappin and Leass, on Mitkov's approach, on topic-focus articulation, and on a collocation feature computed from the Czech National Corpus. The first system is a C5.0 decision-tree classifier that judges each anaphor–candidate pair independently. The second is a ranker whose scoring weights are learned with a Collins-style perceptron and which compares all candidates for an anaphor jointly. On the evaluation test set, the ranker reaches an F-score of 79.43%. This beats the classifier, a rule-based baseline and all previously published Czech systems evaluated on PDT data. The results add evidence from a new language and dataset that ranking suits anaphora resolution better than pairwise classification. The comparison with English work is only approximate, however, because this system relies on gold-standard annotation. ## Key points - **Data:** PDT 2.0 contains 3,168 newspaper texts (49,431 sentences) and 45,174 coreference links. Personal (including zero) and possessive pronouns account for 37.4% of these links (16,888). - **Candidate selection:** candidates are semantic nouns that either precede the anaphor in the same sentence or appear in the previous sentence. This restriction loses the correct antecedent for only about 6% of anaphors. - **F-scores:** - rule baseline BASE 3+2+1: 62.79% - CLASS classifier: 70.17% - CLASS+3+2+1 (classifier with rule fallback): 76.30% - RANK perceptron ranker: 79.43% - **Earlier Czech systems:** a rule-based filter system by Kučová & Žabokrtský (2005) reached 60.4%, and the rule-based system of Nguy & Žabokrtský (2007) reached 74.2%. - **English comparison:** the ranker comes close to the 82.2% F-score that Denis & Baldridge (2008) report for English third-person pronouns, though the tasks and input annotations differ. *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: [Linguistics & languages](https://md.research.elamur.ai/free/shelves/linguistics/) Topics: [Coreference resolution](https://md.research.elamur.ai/free/topics/coreference-resolution/) ## Cited by Cited by 4 papers of our library cite it (of the 140673 whose bibliographies we read); 2 of them have a page here, 2 not yet. - [Supervised Noun Phrase Coreference Research: The First Fifteen Years](https://md.research.elamur.ai/free/papers/ng-2010-supervised-noun-phrase-coreference-research/) - [Cross-lingual Coreference Resolution of Pronouns](https://md.research.elamur.ai/free/papers/novak-2014-cross-lingual-coreference-resolution-pronouns/) ## Cite The paper itself, not this page. BibTeX from the library's record of the work. ```bibtex @inproceedings{ngy2009comparison, title = {{Comparison of Classification and Ranking Approaches to Pronominal Anaphora Resolution in Czech}}, author = {Ngụy, Giang Linh and Novák, Václav and Žabokrtský, Zdeněk}, booktitle = {Proceedings of the SIGDIAL 2009 Conference}, year = {2009}, doi = {10.3115/1708376.1708415}, url = {https://doi.org/10.3115/1708376.1708415} } ``` - [← previous CATiB: The Columbia Arabic Treebank](https://md.research.elamur.ai/free/papers/aclbulk-2009-habash-catib-columbia-arabic-treebank/) - [next → Conundrums in Noun Phrase Coreference Resolution: Making Sense of the State-of-the-Art](https://md.research.elamur.ai/free/papers/stoyanov-2009-conundrums-noun-phrase-coreference-resolution/) - [↑ back to papers of 2009](https://md.research.elamur.ai/free/papers/2009/) ## References 1 references, 0 of them with a card of ours. ↗ leads to the work, «find» searches for one we have no id for yet. 1. Chinatsu Aone and Scott William Bennett. 1995. Evaluating automated and manual acquisition of [find](https://scholar.google.com/scholar?q=Chinatsu+Aone+and+Scott+William+Bennett%2E+1995%2E+Evaluating+automated+and+manual+acquisition+of)