Corpus Annotation for Parser Evaluation

We describe a recently developed corpus annotation scheme for evaluating parsers that avoids shortcomings of current methods. The scheme encodes grammatical relations between heads and dependents, and has been used to mark up a new public-domain corpus of naturally occurring English text. We show how the corpus can be used to evaluate the accuracy of a robust parser, and relate the corpus to extant resources.Comment: 7 pages, LaTeX (uses eaclap.sty

Can Subcategorisation Probabilities Help a Statistical Parser?

Research into the automatic acquisition of lexical information from corpora is starting to produce large-scale computational lexicons containing data on the relative frequencies of subcategorisation alternatives for individual verbal predicates. However, the empirical question of whether this type of frequency information can in practice improve the accuracy of a statistical parser has not yet been answered. In this paper we describe an experiment with a wide-coverage statistical grammar and parser for English and subcategorisation frequencies acquired from ten million words of text which shows that this information can significantly improve parse accuracy.Comment: 9 pages, uses colacl.st

Off-line Constraint Propagation for Efficient HPSG Processing

We investigate the use of a technique developed in the constraint programming community called constraint propagation to automatically make a HPSG theory more specific at those places where linguistically motivated underspecification would lead to inefficient processing. We discuss two concrete HPSG examples showing how off-line constraint propagation helps improve processing efficiency.Comment: 10 pages, uuencoded gzipped Postscrip

Applied morphological processing of English

We describe two newly developed computational tools for morphological processing: a program for analysis of English inflectional morphology, and a morphological generator, automatically derived from the analyser. The tools are fast, being based on finite-state techniques, have wide coverage, incorporating data from various corpora and machine readable dictionaries, and are robust, in that they are able to deal effectively with unknown words. The tools are freely available. We evaluate the accuracy and speed of both tools and discuss a number of practical applications in which they have been put to use

Predictive Left-To-Right Parsing Of A Restricted Variant Of Tag(ld/lp)

By means of a factorization of linear precedence (LP) information in Tree Adjoining Grammar (TAG), the possibility to capture syntactic generalizations can be enhanced, especially with respect to languages which exhibit relative free wordorder. In TAG(LD/LP) LP-information is factorized in a way reminiscent of the ID/LP format of CFGs. However, in contrast to its context-free counterpart, in TAG(LD/LP) entanglement of constituents is allowed by admitting not only the permutation of sister nodes, but also of non-sister nodes in a structural description. In this paper a generalization of the predictive left-to-right parser for TAG is presented which is able to handle a restricted variant of TAG(LD/LP), which allows the permutation of sister nodes and non-sister nodes within elementary structures, the basic building blocks of TAG(LD/LP)

Selective Magic HPSG Parsing

We propose a parser for constraintlogic grammars implementing HPSG that combines the advantages of dynamic bottom-up and advanced topdown control. The parser allows the user to apply magic compilation to specific constraints in a grammar which as a result can be processed dynamically in a bottom-up and goal-directed fashion. State of the art top-down processing techniques are used to deal with the remaining constraints. We discuss various aspects concerning the implementation of the parser as part of a grammar development system. 1 Introduction In case of large grammars the space requirements of dynamic parsing often outweigh the benefit of not duplicating sub-computations. We propose a parser that avoids this drawback through combining the advantages of dynamic bottom-up and advanced top-down control. 1 The underlying idea is to achieve faster parsing by avoiding tabling on sub-computations which are not expensive. The so-called selective magic parser allows the user to apply magi..

Off-line constraint propagation for efficient HPSG processing

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