--- title: "Comparison of Classification and Ranking Approaches to Pronominal Anaphora Resolution — Ngụy 2009" description: "Using the manually annotated textual coreference in the Prague Dependency Treebank 2.0, the authors… 82.2% F-score. 1 reference, cited by 4 papers here." 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/en/papers/ngy-2009-comparison-classification-ranking-approaches-pronominal/" --- [Elamur Research](https://md.research.elamur.ai/free/en/) · [this page in HTML](https://research.elamur.ai/free/en/papers/ngy-2009-comparison-classification-ranking-approaches-pronominal/) [home](https://md.research.elamur.ai/free/en/) / [papers](https://md.research.elamur.ai/free/en/papers/) / [2009](https://md.research.elamur.ai/free/en/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 and [Zdeněk Žabokrtský](https://md.research.elamur.ai/free/en/authors/zdenek-zabokrtsky/) · **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, 2026-10-14) · [4](https://md.research.elamur.ai/free/en/papers/ngy-2009-comparison-classification-ranking-approaches-pronominal/cited-by/) in our library, of the 140,884 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/en/shelves/linguistics/) Topics: [🔗 Coreference resolution](https://md.research.elamur.ai/free/en/topics/coreference-resolution/) ## Institutions - [Charles University](https://md.research.elamur.ai/free/en/universities/charles-university/) — University, Prague, Czechia · 99 works · 18,879 citations ## Cite Cite as: Giang Linh Ngụy, Václav Novák and Zdeněk Žabokrtský. 2009. Comparison of Classification and Ranking Approaches to Pronominal Anaphora Resolution in Czech. Proceedings of the SIGDIAL 2009 Conference. The paper itself, not this page. BibTeX from the library's record of the work. ```bibtex @inproceedings{nguy2009comparison, title = {{Comparison of Classification and Ranking Approaches to Pronominal Anaphora Resolution in Czech}}, author = {Giang Linh Ngụy, Václav Novák and Zdeněk Žabokrtský}, booktitle = {Proceedings of the SIGDIAL 2009 Conference}, year = {2009}, doi = {10.3115/1708376.1708415}, url = {https://doi.org/10.3115/1708376.1708415} } ``` - [← previous Evaluating a Statistical CCG Parser on Wikipedia](https://md.research.elamur.ai/free/en/papers/honnibal-2009-evaluating-statistical-ccg-parser-wikipedia/) - [next → Multi-word expressions in textual inference: Much ado about nothing?](https://md.research.elamur.ai/free/en/papers/marneffe-2009-multi-word-expressions-textual-inference/) - [↑ back to papers of 2009](https://md.research.elamur.ai/free/en/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)