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29
Practical Unificationbased Parsing of Natural Language
, 1993
"... The thesis describes novel techniques and algorithms for the practical parsing of realistic Natural Language (NL) texts with a widecoverage unificationbased grammar of English. The thesis tackles two of the major problems in this area: firstly, the fact that parsing realistic inputs with such gr ..."
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Cited by 49 (7 self)
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The thesis describes novel techniques and algorithms for the practical parsing of realistic Natural Language (NL) texts with a widecoverage unificationbased grammar of English. The thesis tackles two of the major problems in this area: firstly, the fact that parsing realistic inputs with such grammars can be computationally very expensive, and secondly, the observation that many analyses are often assigned to an input, only one of which usually forms the basis of the correct interpretation. The thesis starts by presenting a new unification algorithm, justifies why it is wellsuited to practical NL parsing, and describes a bottomup active chart parser which employs this unification algorithm together with several other novel processing and optimisation techniques. Empirical results demonstrate that an implementation of this parser has significantly better practical
The Use of Shared Forests in Tree Adjoining Grammar Parsing
 In Proceedings of EACL '93
, 1993
"... We study parsing of tree adjoining grammars with particular emphasis on the use of shared forests to represent all the parse trees deriving a wellformed string. We show that there are two distinct ways of representing the parse forest one of which involves the use of linear indexed grammars ..."
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Cited by 14 (0 self)
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We study parsing of tree adjoining grammars with particular emphasis on the use of shared forests to represent all the parse trees deriving a wellformed string. We show that there are two distinct ways of representing the parse forest one of which involves the use of linear indexed grammars and the other the use of contextfree grammars.
Practical Experiments in Parsing using Tree Adjoining Grammars
 In Proc. of TAG+5
, 2000
"... We present an implementation of a chartbased headcorner parsing algorithm for lexicalized Tree Adjoining Grammars. We report on some practical experiments where we parse 2250 sentences from the Wall Street Journal using this parser. In these experiments the parser is run without any statistical pr ..."
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Cited by 14 (2 self)
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We present an implementation of a chartbased headcorner parsing algorithm for lexicalized Tree Adjoining Grammars. We report on some practical experiments where we parse 2250 sentences from the Wall Street Journal using this parser. In these experiments the parser is run without any statistical pruning; it produces all valid parses for each sentence in the form of a shared derivation forest. The parser uses a large Treebank Grammar with 6789 tree templates with about 120; 000 lexicalized trees. The results suggest that the observed complexity of parsing for LTAG is dominated by factors other than sentence length.
Minimalist Grammars and Recognition
"... Recent work has shown how basic ideas of the minimalist tradition intransformational syntax can be captured in a simple generative formalism, a"der:"AII] al minimalism." Thisfr]]I[L" can model "rel nant movement" analyses, which yield mor e complex antecedenttr ace r elations, suggesting a new and ..."
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Cited by 9 (1 self)
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Recent work has shown how basic ideas of the minimalist tradition intransformational syntax can be captured in a simple generative formalism, a"der:"AII] al minimalism." Thisfr]]I[L" can model "rel nant movement" analyses, which yield mor e complex antecedenttr ace r elations, suggesting a new and significant sense in which linguistic str ctur esar "chain based." Michaelis (1998) showed that these grI] mar cor" spond to a certain kind of linear context free r write system, and this paper takes the next step of adapting ther ecognition methods for "nonconcatenative"grOO[]" (Weir 1988; Seki et al., 1991; Boullier , 1999). This tur ns out to be quite straightforward once the grammars are set out appropriately.
A Generalization of Mildly ContextSensitive Formalisms
 University of Pennsylvania
, 1998
"... Introduction In (Boullier 98), we presented range concatenation grammars (RCGs), a syntactic formalism which is a variant of literal movement grammars (LMGs), described in (Groenink 97), and which is also related to the framework of LFP developed by (Rounds 88). In fact it may be considered to lie ..."
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Cited by 8 (4 self)
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Introduction In (Boullier 98), we presented range concatenation grammars (RCGs), a syntactic formalism which is a variant of literal movement grammars (LMGs), described in (Groenink 97), and which is also related to the framework of LFP developed by (Rounds 88). In fact it may be considered to lie halfway between their respective string and integer versions; RCGs retain from the string version of LMGs or LFPs the notion of concatenation, applying it to ranges rather than strings, and from their integer version the ability to handle only (part of) the source text. The basis of RCGs is the notion of range, a couple of integers hi :: ji which denotes the occurrence of some substring a i+1 : : : a j in an input string a 1 : : : a n . Of course, only consecutive ranges can be concatenated into a new range . This formalism, which extends CFGs, aims at being a convincing challenger as a syntactic base for various tasks, especially in natural language processing. We have shown that the po
Another Facet of LIG Parsing
, 1996
"... : In this paper we present a new parsing algorithm for linear indexed grammars (LIGs) in the same spirit as the one described in (VijayShanker and Weir, 1993) for tree adjoining grammars. For a LIG L and an input string x of length n, we build a non ambiguous contextfree grammar whose sentences ar ..."
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Cited by 6 (1 self)
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: In this paper we present a new parsing algorithm for linear indexed grammars (LIGs) in the same spirit as the one described in (VijayShanker and Weir, 1993) for tree adjoining grammars. For a LIG L and an input string x of length n, we build a non ambiguous contextfree grammar whose sentences are all (and exclusively) valid derivation sequences in L which lead to x. We show that this grammar can be built in O(n 6 ) time and that individual parses can be extracted in linear time with the size of the extracted parse tree. Though this O(n 6 ) upper bound does not improve over previous results, the average case behaves much better. Moreover, practical parsing times can be decreased by some statically performed computations. Keywords: mildly contextsensitive parsing, ambiguity, parse tree, shared parse forest. (R#sum# : tsvp) This report is an extended version of the ACL'96 paper (Boullier, 1996). * Email: Pierre.Boullier@inria.fr Unit de recherche INRIA Rocquencourt Domaine de ...
A general technique to train language models on language models
 Computational Linguistics
, 2005
"... models ..."
Efficiency in UnificationBased NBest Parsing
, 2007
"... We extend a recently proposed algorithm for nbest unpacking of parse forests to deal efficiently with (a) Maximum Entropy (ME) parse selection models containing important classes of nonlocal features, and (b) forests produced by unification grammars containing significant proportions of globally i ..."
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Cited by 6 (2 self)
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We extend a recently proposed algorithm for nbest unpacking of parse forests to deal efficiently with (a) Maximum Entropy (ME) parse selection models containing important classes of nonlocal features, and (b) forests produced by unification grammars containing significant proportions of globally inconsistent analyses. The new algorithm empirically exhibits a linear relationship between processing time and the number of analyses unpacked at all degrees of ME feature nonlocality; in addition, compared with agendadriven bestfirst parsing and exhaustive parsing with posthoc parse selection it leads to improved parsing speed, coverage, and accuracy.
Resource logics and minimalist grammars
 Proceedings ESSLLI’99 workshop (Special issue Language and Computation
, 2002
"... This ESSLLI workshop is devoted to connecting the linguistic use of resource logics and categorial grammar to minimalist grammars and related generative grammars. Minimalist grammars are relatively recent, and although they stem from a long tradition of work in transformational grammar, they are lar ..."
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Cited by 4 (0 self)
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This ESSLLI workshop is devoted to connecting the linguistic use of resource logics and categorial grammar to minimalist grammars and related generative grammars. Minimalist grammars are relatively recent, and although they stem from a long tradition of work in transformational grammar, they are largely informal apart from a few research papers. The study of resource logics, on the other hand, is formal and stems naturally from a long logical tradition. So although there appear to be promising connections between these traditions, there is at this point a rather thin intersection between them. The papers in this workshop are consequently rather diverse, some addressing general similarities between the two traditions, and others concentrating on a thorough study of a particular point. Nevertheless they succeed in convincing us of the continuing interest of studying and developing the relationship between the minimalist program and resource logics. This introduction reviews some of the basic issues and prior literature. 1 The interest of a convergence What would be the interest of a convergence between resource logical investigations of
Combining Supertagging and Lexicalized TreeAdjoining Grammar Parsing
"... In this paper we study various reasons and mechanisms for combining Supertagging with Lexicalized TreeAdjoining Grammar (LTAG) parsing. Because of the highly lexicalized nature of the LTAG formalism, we experimentally show that notions other than sentence length play a factor in observed parse time ..."
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Cited by 4 (0 self)
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In this paper we study various reasons and mechanisms for combining Supertagging with Lexicalized TreeAdjoining Grammar (LTAG) parsing. Because of the highly lexicalized nature of the LTAG formalism, we experimentally show that notions other than sentence length play a factor in observed parse times. In particular, syntactic lexical ambiguity and sentence complexity (both are terms we define in this paper) are the dominant factors that affect parsing efficiency. We show how a Supertagger can be used to drastically reduce the syntactic lexical ambiguity for a given input and can be used in combination with an LTAG parser to radically improve parsing efficiency. We then turn our attention to from parsing efficiency to parsing accuracy and provide a method by which we can effectively combine the output of a Supertagger and a statistical LTAG parser using a cotraining algorithm for bootstrapping new labeled data. This combination method can be used to incorporate new labeled data from raw text to improve parsing accuracy.