142 research outputs found
Lexicalization and Grammar Development
In this paper we present a fully lexicalized grammar formalism as a
particularly attractive framework for the specification of natural language
grammars. We discuss in detail Feature-based, Lexicalized Tree Adjoining
Grammars (FB-LTAGs), a representative of the class of lexicalized grammars. We
illustrate the advantages of lexicalized grammars in various contexts of
natural language processing, ranging from wide-coverage grammar development to
parsing and machine translation. We also present a method for compact and
efficient representation of lexicalized trees.Comment: ps file. English w/ German abstract. 10 page
Developing a TT-MCTAG for German with an RCG-based parser
Developing linguistic resources, in particular grammars, is known to be a complex task in itself, because of (amongst others) redundancy and consistency issues. Furthermore some languages can reveal themselves hard to describe because of specific characteristics, e.g. the free word order in German. In this context, we present (i) a framework allowing to describe tree-based grammars, and (ii) an actual fragment of a core multicomponent tree-adjoining grammar with tree tuples (TT-MCTAG) for German developed using this framework. This framework combines a metagrammar compiler and a parser based on range concatenation grammar (RCG) to respectively check the consistency and the correction of the grammar. The German grammar being developed within this framework already deals with a wide range of scrambling and extraction phenomena
Disambiguation of Super Parts of Speech (or Supertags): Almost Parsing
In a lexicalized grammar formalism such as Lexicalized Tree-Adjoining Grammar
(LTAG), each lexical item is associated with at least one elementary structure
(supertag) that localizes syntactic and semantic dependencies. Thus a parser
for a lexicalized grammar must search a large set of supertags to choose the
right ones to combine for the parse of the sentence. We present techniques for
disambiguating supertags using local information such as lexical preference and
local lexical dependencies. The similarity between LTAG and Dependency grammars
is exploited in the dependency model of supertag disambiguation. The
performance results for various models of supertag disambiguation such as
unigram, trigram and dependency-based models are presented.Comment: ps file. 8 page
Some Novel Applications of Explanation-Based Learning to Parsing Lexicalized Tree-Adjoining Grammars
In this paper we present some novel applications of Explanation-Based
Learning (EBL) technique to parsing Lexicalized Tree-Adjoining grammars. The
novel aspects are (a) immediate generalization of parses in the training set,
(b) generalization over recursive structures and (c) representation of
generalized parses as Finite State Transducers. A highly impoverished parser
called a ``stapler'' has also been introduced. We present experimental results
using EBL for different corpora and architectures to show the effectiveness of
our approach.Comment: uuencoded postscript fil
On Parsing CHILDES
Research on child language acquisition would benefit from the availability of a large body of syntactically parsed utterances between parents and children. We consider the problem of generating such a ``treebank'' from the CHILDES corpus, which currently contains primarily orthographically transcribed speech tagged for lexical category
Encoding Lexicalized Tree Adjoining Grammars with a Nonmonotonic Inheritance Hierarchy
This paper shows how DATR, a widely used formal language for lexical
knowledge representation, can be used to define an LTAG lexicon as an
inheritance hierarchy with internal lexical rules. A bottom-up featural
encoding is used for LTAG trees and this allows lexical rules to be implemented
as covariation constraints within feature structures. Such an approach
eliminates the considerable redundancy otherwise associated with an LTAG
lexicon.Comment: Latex source, needs aclap.sty, 8 page
Punctuation in Quoted Speech
Quoted speech is often set off by punctuation marks, in particular quotation
marks. Thus, it might seem that the quotation marks would be extremely useful
in identifying these structures in texts. Unfortunately, the situation is not
quite so clear. In this work, I will argue that quotation marks are not
adequate for either identifying or constraining the syntax of quoted speech.
More useful information comes from the presence of a quoting verb, which is
either a verb of saying or a punctual verb, and the presence of other
punctuation marks, usually commas. Using a lexicalized grammar, we can license
most quoting clauses as text adjuncts. A distinction will be made not between
direct and indirect quoted speech, but rather between adjunct and non-adjunct
quoting clauses.Comment: 11 pages, 11 ps figures, Proceedings of SIGPARSE 96 - Punctuation in
Computational Linguistic
TuLiPA : towards a multi-formalism parsing environment for grammar engineering
In this paper, we present an open-source parsing environment (TĂĽbingen Linguistic Parsing Architecture, TuLiPA) which uses Range Concatenation Grammar (RCG) as a pivot formalism, thus opening the way to the parsing of several mildly context-sensitive formalisms. This environment currently supports tree-based grammars (namely Tree-Adjoining Grammars (TAG) and Multi-Component Tree-Adjoining Grammars with Tree Tuples (TT-MCTAG)) and allows computation not only of syntactic structures, but also of the corresponding semantic representations. It is used for the development of a tree-based grammar for German
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