Results 1 - 10 of 24

Pipeline Iteration

by Kristy Hollingshead, Brian Roark
"... This paper presents pipeline iteration, an approach that uses output from later stages of a pipeline to constrain earlier stages of the same pipeline. We demonstrate significant improvements in a state-of-the-art PCFG parsing pipeline using base-phrase constraints, derived either from later stages o ..."
Abstract - Cited by 13 (2 self) - Add to MetaCart
This paper presents pipeline iteration, an approach that uses output from later stages of a pipeline to constrain earlier stages of the same pipeline. We demonstrate significant improvements in a state-of-the-art PCFG parsing pipeline using base-phrase constraints, derived either from later stages

Selftraining PCFG grammars with latent annotations across languages

by Zhongqiang Huang - In EMNLP , 2009
"... We investigate the effectiveness of selftraining PCFG grammars with latent annotations (PCFG-LA) for parsing languages with different amounts of labeled training data. Compared to Charniak’s lexicalized parser, the PCFG-LA parser was more effectively adapted to a language for which parsing has been ..."
Abstract - Cited by 41 (8 self) - Add to MetaCart
stateof-the-art parsing accuracies for a single parser on both English (91.5%) and Chinese (85.2%). 1

Large-Scale Corpus-Driven PCFG Approximation of an HPSG

by Yi Zhang, Hans-ulrich Krieger
"... We present a novel corpus-driven approach towards grammar approximation for a linguistically deep Head-driven Phrase Structure Grammar. With an unlexicalized probabilistic context-free grammar obtained by Maximum Likelihood Estimate on a largescale automatically annotated corpus, we are able to achi ..."
Abstract - Cited by 2 (0 self) - Add to MetaCart
to achieve parsing accuracy higher than the original HPSG-based model. Different ways of enriching the annotations carried by the approximating PCFG are proposed and compared. Comparison to the state-of-the-art latent-variable PCFG shows that our approach is more suitable for the grammar approximation task

PCFG Induction for Unsupervised Parsing and Language Modelling

by James Scicluna, Colin De La Higuera
"... The task of unsupervised induction of probabilistic context-free grammars (PCFGs) has attracted a lot of attention in the field of computational linguistics. Although it is a difficult task, work in this area is still very much in demand since it can contribute to the advancement of language parsing ..."
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and infers correctly even from small samples. Our analysis shows that the type of grammars induced by our algorithm are, in theory, capable of modelling natural language. One of our experiments shows that our algorithm can potentially outperform the state-of-the-art in unsupervised parsing on the WSJ10

Long-distance dependency resolution in automatically acquired wide-coverage PCFG-based LFG approximations

by Aoife Cahill, Michael Burke, Josef Van Genabith, Andy Way - In Proceedings of the 42nd Meeting of the ACL , 2004
"... This paper shows how finite approximations of long distance dependency (LDD) resolution can be obtained automatically for wide-coverage, robust, probabilistic Lexical-Functional Grammar (LFG) resources acquired from treebanks. We extract LFG subcategorisation frames and paths linking LDD reentrancie ..."
Abstract - Cited by 93 (32 self) - Add to MetaCart
700 Dependency Bank (King et al., 2003), performing at the same or a slightly better level than state-of-the-art hand-crafted grammars (Kaplan et al., 2004). 1

Enhancing unlexicalized parsing performance using a wide coverage lexicon, fuzzy tag-set mapping, and em-hmm-based lexical probabilities

by Yoav Goldberg, Reut Tsarfaty, Meni Adler, Michael Elhadad - In Proc. of EACL , 2009
"... We present a framework for interfacing a PCFG parser with lexical information from an external resource following a different tagging scheme than the treebank. This is achieved by defining a stochastic mapping layer between the two resources. Lexical probabilities for rare events are estimated in a ..."
Abstract - Cited by 21 (6 self) - Add to MetaCart
semi-supervised manner from a lexicon and large unannotated corpora. We show that this solution greatly enhances the performance of an unlexicalized Hebrew PCFG parser, resulting in state-of-the-art Hebrew parsing results both when a segmentation oracle is assumed, and in a real-word parsing scenario

Antecedent Recovery: Experiments with a Trace Tagger

by Peter Dienes, P Eter Dienes, Amit Dubey - In Proceedings of the Conference on Empirical Methods in Natural Language Processing , 2003
"... We present a novel, two-step approach for detecting non-local dependencies. First a shallow trace tagger finds extraction sites and second, working on the output of the tagger, a PCFG-based parser recovers the extracted constituents. This method achieves state-of-the-art performance on antecedent re ..."
Abstract - Cited by 16 (1 self) - Add to MetaCart
We present a novel, two-step approach for detecting non-local dependencies. First a shallow trace tagger finds extraction sites and second, working on the output of the tagger, a PCFG-based parser recovers the extracted constituents. This method achieves state-of-the-art performance on antecedent

Collins-LA: Collins’ Head-Driven Model with Latent Annotation

by Seung-hoon Na, Meixun Jin, In-su Kang, Jong-hyeok Lee , 2008
"... Recent works on parsing have reported that the lexicalization does not have a serious role for parsing accuracy. Latent-annotation methods such as PCFG-LA are one of the most promising un-lexicalized approaches, and reached the-state-of-art performance. However, most works on latent annotation have ..."
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Recent works on parsing have reported that the lexicalization does not have a serious role for parsing accuracy. Latent-annotation methods such as PCFG-LA are one of the most promising un-lexicalized approaches, and reached the-state-of-art performance. However, most works on latent annotation have

A Comparative Study of Target Dependency Structures for Statistical Machine Translation

by Xianchao Wu, Katsuhito Sudoh, Kevin Duh, Hajime Tsukada, Masaaki Nagata
"... This paper presents a comparative study of target dependency structures yielded by several state-of-the-art linguistic parsers. Our approach is to measure the impact of these nonisomorphic dependency structures to be used for string-to-dependency translation. Besides using traditional dependency par ..."
Abstract - Cited by 1 (0 self) - Add to MetaCart
This paper presents a comparative study of target dependency structures yielded by several state-of-the-art linguistic parsers. Our approach is to measure the impact of these nonisomorphic dependency structures to be used for string-to-dependency translation. Besides using traditional dependency

Effective Constituent Projection across Languages

by Wenbin Jiang, Yajuan Lü, Yang Liu, Qun Liu
"... We describe an effective constituent projection strategy, where constituent projection is performed on the basis of dependency projection. Especially, a novel measurement is proposed to evaluate the candidate projected constituents for a target language sentence, and a PCFG-style parsing procedure i ..."
Abstract - Cited by 1 (1 self) - Add to MetaCart
is then used to search for the most probable projected constituent tree. Experiments show that, the parser trained on the projected treebank can significantly boost a state-of-the-art supervised parser. When integrated into a tree-based machine translation system, the projected parser leads to translation
Results 1 - 10 of 24