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31
PCFG Models of Linguistic Tree Representations
 Computational Linguistics
, 1998
"... This paper points out that the Penn lI treebank representations are of the kind predicted to have such an effect, and describes a simple node relabeling transformation that improves a treebank PCFGbased parser's average precision and recall by around 8%, or approximately half of the performance dif ..."
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Cited by 211 (9 self)
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This paper points out that the Penn lI treebank representations are of the kind predicted to have such an effect, and describes a simple node relabeling transformation that improves a treebank PCFGbased parser's average precision and recall by around 8%, or approximately half of the performance difference between a simple PCFG model and the best broadcoverage parsers available today. This performance variation comes about because any PCFG, and hence the corpus of trees from which the PCFG is induced, embodies independence assumptions about the distribution of words and phrases. The particular independence assumptions implicit in a tree representation can be studied theoretically and investigated empirically by means of a tree transformation / detransformation process
Efficient Parsing for Bilexical ContextFree Grammars and Head Automaton Grammars
 IN ACL 37
, 1999
"... Several recent stochastic parsers use bilexical grammars, where each word type idiosyncratically prefers particular complements with particular head words. We present O(n^4) parsing algorithms for two bilexical formalisms, improving the prior upper bounds of O(n^5). For a common special case that wa ..."
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Cited by 92 (19 self)
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Several recent stochastic parsers use bilexical grammars, where each word type idiosyncratically prefers particular complements with particular head words. We present O(n^4) parsing algorithms for two bilexical formalisms, improving the prior upper bounds of O(n^5). For a common special case that was known to allow O(n³) parsing (Eisner, 1997), we present an O(n³) algorithm with an improved grammar constant.
Paradigmatic Morphology
, 1989
"... We present a notation for the declarative statement of morphological relationships and lexical rules, based on the traditional notion of Word and Paradigm (cf Hockett 1954). The phenomenon of blocking arises from a generalized version of Kiparsky's (1973) Elsewhere Condition, stated in terms of orde ..."
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Cited by 33 (1 self)
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We present a notation for the declarative statement of morphological relationships and lexical rules, based on the traditional notion of Word and Paradigm (cf Hockett 1954). The phenomenon of blocking arises from a generalized version of Kiparsky's (1973) Elsewhere Condition, stated in terms of ordering by subsumption over paradigms. Orthographic constraints on morphemic alternation are described by means of string equations (Sickmann 1975). We indicate some criticisms to be made of our approach from both linguistic and computational perspectives and relate our approach to others such as FiniteState Morphology (Koskenniemi 1983), DAII (Gazdar and Evans 1989) and objectoriented morphophonemics (de Smedt 1984, Daelemans 1988). Finally, we discuss the questions of whether a system involving string equations allows a reduction to finitestate techniques.
Finitestate Approximation of Constraintbased Grammars using Leftcorner Grammar Transforms
, 1998
"... This paper describes how to construct a finitestate machine (FSM) approximating a 'unificationbased' grammar using a ]eftcorner grammar transform. The approximation is presented as a series of grammar transforms, and is exact for leftlinear and rightlinear CFGs, and for trees up to a userspecif ..."
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Cited by 17 (0 self)
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This paper describes how to construct a finitestate machine (FSM) approximating a 'unificationbased' grammar using a ]eftcorner grammar transform. The approximation is presented as a series of grammar transforms, and is exact for leftlinear and rightlinear CFGs, and for trees up to a userspecified depth of centerembedding.
AutomataTheoretic Models of Mutation and Alignment
 In International Conference on Intelligent Systems in Molecular Biology
, 1995
"... Finitestate automata called transducers, which have both input and output, can be used to model simple mechanisms of biological mutation. We present a methodology whereby numerically weighted versions of such specifications can be mechanically adapted to create string edit machines that are essent ..."
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Cited by 16 (3 self)
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Finitestate automata called transducers, which have both input and output, can be used to model simple mechanisms of biological mutation. We present a methodology whereby numerically weighted versions of such specifications can be mechanically adapted to create string edit machines that are essentially equivalent to recurrence relations of the sort that characterize dynamic programming alignment algorithms. Based on this, we have developed a visual programming system for designing new alignment algorithms in a rapidprototyping fashion. 1 Introduction Finitestate automata have an important place in computer science, often representing simple models of computation as the recognition or generation of strings of symbols. A wide variety of such automata have been intensively studied, including weighted automata which have numbers associated with transitions between states, and transducers which have both input and output. Allison and coworkers [2] have proposed the use of finitestat...
Specifying Architectures for Language Processing: Process, Control, and Memory in Parsing and Interpretation
, 1997
"... ing away from irrelevant details is a theoretical virtue, but the kinds of abstractions that module geography makes can lead to incorrect inferences from data. That such a possibility exists is clearly demonstrated by the working memory research of Just & Carpenter (1992). Briefly, Just and Carpente ..."
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Cited by 12 (6 self)
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ing away from irrelevant details is a theoretical virtue, but the kinds of abstractions that module geography makes can lead to incorrect inferences from data. That such a possibility exists is clearly demonstrated by the working memory research of Just & Carpenter (1992). Briefly, Just and Carpenter have argued that some garden path effects that were previously interpreted in terms of a syntactically encapsulated module can instead be explained by individual differences in working memory capacity. Such an explanation is not considered in a theoretical framework that systematically ignores the role of memory structures in parsing. This point should be taken regardless of whether one is convinced by the current body of empirical support for this particular modelthe fact remains that such an explanation could in principle account for the data, and these alternative explanations are only discovered by developing functionally complete architectures. The next few sections describes what ...
DataOriented Models of Parsing and Translation
, 2005
"... A dissertation submitted in fulfilment of the requirements for the award of ..."
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Cited by 12 (2 self)
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A dissertation submitted in fulfilment of the requirements for the award of
A Generalized Greibach Normal Form for Definite Clause Grammars
, 1992
"... An arbitrary definite clause grammar can be transfomled into a socalled Generalized Oreibach Normal Form (GGNF), a generalization of the classical Groibach Norreal Form (GNF) for contextfree grammars. The normalized definite clause grammar is declarafively equivalent to the original definite claus ..."
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Cited by 9 (3 self)
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An arbitrary definite clause grammar can be transfomled into a socalled Generalized Oreibach Normal Form (GGNF), a generalization of the classical Groibach Norreal Form (GNF) for contextfree grammars. The normalized definite clause grammar is declarafively equivalent to the original definite clause grammar, that is, it assigns the same analyses to the same strings. Offiineparsability of the original grammar is reflected in an elementary textual property of the transformed grammar. When this property holds. a direct (topdown) Prolog implementation of the normalized grammar solves the parsing problem: all solutions are enumerated on backtracking and execution tenninales. When specialized to tlte simpler case of contextfree grammars, the GGNF provides a variant to rite GNF, where the ramsformed contextfree grammar not only generates the same strings as the original grammar, but also preserves their degrees of ambiguity (this last prope ty does not hold for the GNF). The GGNF seems to be the first normal form result for DCGs. It provides an explicit factorization of the polentis] sources of undecidability for the parsing problem, and offera valuable insights on the computational structure of unification grammars in general.
A Survey of Parallel Search Algorithms for Discrete Optimization Problems
 ORSA JOURNAL ON COMPUTING
, 1993
"... Discrete optimization problems (DOPs) arise in various applications such as planning, scheduling, computer aided design, robotics, game playing and constraint directed reasoning. Often, a DOP is formulated in terms of finding a (minimum cost) solution path in a graph from an initial node to a goal n ..."
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Cited by 7 (0 self)
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Discrete optimization problems (DOPs) arise in various applications such as planning, scheduling, computer aided design, robotics, game playing and constraint directed reasoning. Often, a DOP is formulated in terms of finding a (minimum cost) solution path in a graph from an initial node to a goal node and solved by graph/tree search methods. Availability of parallel computers has created substantial interest in exploring parallel formulations of these graph and tree search methods. This article provides a survey of various parallel search algorithms such as Backtracking, IDA*, A*, BranchandBound techniques and Dynamic Programming. It addresses issues related to load balancing, communication costs, scalability and the phenomenon of speedup anomalies in parallel search.