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16
Improved leftcorner chart parsing for large contextfree grammars
 In Proceedings of the Sixth International Workshop on Parsing Technologies
, 2000
"... We develop an improved form of leftcorner chart parsing for large contextfree grammars, introducing improvements that result in significant speedups compared to previouslyknown variants of leftcorner parsing. We also compare our method to several other major parsing approaches, and find that ou ..."
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Cited by 19 (1 self)
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We develop an improved form of leftcorner chart parsing for large contextfree grammars, introducing improvements that result in significant speedups compared to previouslyknown variants of leftcorner parsing. We also compare our method to several other major parsing approaches, and find that our improved leftcorner parsing method outperforms each of these across a range of grammars. Finally, we also describe a new technique for minimizing the extra information needed to efficiently recover parses from the data structures built in the course of parsing. 1
An Optimal Tabular Parsing Algorithm
 In 32nd Annual Meeting of the Association for Computational Linguistics, Proceedings of the Conference
"... In this paper we relate a number of parsing algorithms which have been developed in very different areas of parsing theory, and which include deterministic algorithms, tabular algorithms, and a parallel algorithm. We show that these algorithms are based on the same underlying ideas. ..."
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Cited by 17 (10 self)
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In this paper we relate a number of parsing algorithms which have been developed in very different areas of parsing theory, and which include deterministic algorithms, tabular algorithms, and a parallel algorithm. We show that these algorithms are based on the same underlying ideas.
Efficient Tabular LR Parsing
 IN 34TH ANNUAL MEETING OF THE ASSOCIATION FOR COMPUTATIONAL LINGUISTICS
, 1996
"... We give a new treatment of tabular LR parsing, which is an alternative to Tomita's generalized LR algorithm. The advantage is twofold. Firstly, our treatment is conceptually more attractive because it uses simpler concepts, such as grammar trans formations and standard tabulation techniques a ..."
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Cited by 14 (7 self)
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We give a new treatment of tabular LR parsing, which is an alternative to Tomita's generalized LR algorithm. The advantage is twofold. Firstly, our treatment is conceptually more attractive because it uses simpler concepts, such as grammar trans formations and standard tabulation techniques also know as chart parsing. Secondly, the static and dynamic complexity of parsing, both in space and time, is significantly reduced.
Conventional Natural Language Processing in the NWO Priority Programme on Language and Speech Technology
, 1996
"... ..."
Probabilistic parsing strategies
 In 42nd Annual Meeting of the Association for Computational Linguistics
, 2004
"... We present new results on the relation between purely symbolic contextfree parsing strategies and their probabilistic counterparts. Such parsing strategies are seen as constructions of pushdown devices from grammars. We show that preservation of probability distribution is possible under two condi ..."
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Cited by 6 (1 self)
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We present new results on the relation between purely symbolic contextfree parsing strategies and their probabilistic counterparts. Such parsing strategies are seen as constructions of pushdown devices from grammars. We show that preservation of probability distribution is possible under two conditions, viz. the correctprefix property and the property of strong predictiveness. These results generalize existing results in the literature that were obtained by considering parsing strategies in isolation. From our general results we also derive negative results on socalled generalized LR parsing. 1
Survey of Parallel ContextFree Parsing Techniques
, 1997
"... This report describes research done in the context of a subproject of the HPCN project IMPACT. The IMPACT project is headed by the ING bank and is founded by the organization for High Performance Computing and Networking (HPCN). The aim of the specific subproject, in the context of which this report ..."
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Cited by 4 (3 self)
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This report describes research done in the context of a subproject of the HPCN project IMPACT. The IMPACT project is headed by the ING bank and is founded by the organization for High Performance Computing and Networking (HPCN). The aim of the specific subproject, in the context of which this report has been written, is to develop (techniques for) natural language interfaces to information resources, focusing on the use of highperformance computers to achieve acceptable response times. This report is part of the "Parallel Parsing I" research topic. IMPACTNLI19971 ii Preface IMPACT IMPACTNLI19971 IMPACT iii Contents Preface i 1 Introduction 1 2 Basics 3
A Customized Grammar Workbench
 English Language Corpora: Design, Analysis and Exploitation, Papers from the thirteenth International Conference on English Language Research on Computerized Corpora
, 1992
"... In this paper we describe the ideas behind the Grammar Workbench (GWB). The GWB is one of a series of tools for the development of AGFLs (affix grammars over a finite lattice) for natural languages. Its functions comprise a specialised editor, computation of properties, a random generator of sentenc ..."
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Cited by 4 (4 self)
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In this paper we describe the ideas behind the Grammar Workbench (GWB). The GWB is one of a series of tools for the development of AGFLs (affix grammars over a finite lattice) for natural languages. Its functions comprise a specialised editor, computation of properties, a random generator of sentences, and special functions to provide an overview of a grammar. This paper discusses the functions of the GWB, the grammatical formalism AGFLs, and the AGFL project. We also discuss the relationship between the complete development environment for AGFLs and other development environments, both for other grammatical formalisms and for computer programs. 1 Introduction Formal grammars for natural languages tend to become unmanageable as they get larger. Similar problems occur in the development of large computer programs. To overcome these problems with large programs, a number of techniques have been invented in the field of software engineering to ffl structure programs so as to permit deco...
Efficient Decoration of Parse Forests
, 1993
"... This paper deals with affix grammars over a finite lattice (AGFLs). The parameters in AGFLs are called affixes. AGFLs are a simple formalism but have still been proved powerful enough for the description of various natural languages [20]. Contextfree parsing can be implemented very efficiently by c ..."
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Cited by 3 (2 self)
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This paper deals with affix grammars over a finite lattice (AGFLs). The parameters in AGFLs are called affixes. AGFLs are a simple formalism but have still been proved powerful enough for the description of various natural languages [20]. Contextfree parsing can be implemented very efficiently by constructing parse forests. A parse forest is a concise representation of a number of parse trees for an ambiguous sentence. Parse forests can be constructed in polynomial time and require polynomial space for storage, measured in the length of the input sentence. In this paper, the extra parameters of extended contextfree grammars are used to impose restrictions (called context dependencies) on the allowable parse trees. Contextfree parsing must therefore be augmented to calculate the parameters. Affix values for AGFLs can be evaluated efficiently because the domains are finite. The rejection of parse trees based on violated context dependencies is more complicated if parse trees are merged into parse forests. Because of the ambiguous nature of natural language, grammars describing natural languages are necessarily also ambiguous, and therefore context dependencies cannot determine a unique parse tree for every sentence. Instead, some humancomputer interaction is necessary to find the intended parses of sentences.
Predictive HeadCorner Chart Parsing
, 1993
"... HeadCorner (HC) parsing has come up in computational linguistics a few years ago, motivated by linguistic arguments. This idea is a heuristic, rather than a failsafe principle, hence it is relevant indeed to consider the worstcase behaviour of the HC parser. We define a novel predictive headcorn ..."
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Cited by 1 (0 self)
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HeadCorner (HC) parsing has come up in computational linguistics a few years ago, motivated by linguistic arguments. This idea is a heuristic, rather than a failsafe principle, hence it is relevant indeed to consider the worstcase behaviour of the HC parser. We define a novel predictive headcorner chart parser of cubic time complexity. We start with a leftcorner (LC) chart parser, which is easier to understand. Subsequently, the LC chart parser is generalized to an HC chart parser. It is briefly sketched how the parser can be enhanced with feature structures. 1. Introduction "Our Latin teachers were apparently right", Martin Kay (1989) remarks. "You should start [parsing] with the main verb. This will tell you what kinds of subjects and objects to look for and what cases they will be in. When you come to look for these, you should also start by trying to find the main word, because this will tell you most about what else to look for". Headdriven or headcorner parsing has been ...
Are Very Large ContextFree Grammars Tractable?
"... In this paper, we present a method which, in practice, allows to use parsers for languages defined by very large contextfree grammars (over a million symbol occurrences). The idea is to split the parsing process in two passes. A first pass computes a subgrammar which is a specialized part of the l ..."
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Cited by 1 (0 self)
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In this paper, we present a method which, in practice, allows to use parsers for languages defined by very large contextfree grammars (over a million symbol occurrences). The idea is to split the parsing process in two passes. A first pass computes a subgrammar which is a specialized part of the large grammar selected by the input text and various filtering strategies. The second pass is a traditional parser which works with the subgrammar and the input text. This approach is validated by practical experiments performed on a Earleylike parser running on a test set with two large contextfree grammars. 1