1,796 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
XMG : eXtending MetaGrammars to MCTAG
In this paper, we introduce an extension of the XMG system (eXtensibleMeta-Grammar) in order to allow for the description of Multi-Component Tree Adjoining Grammars. In particular, we introduce the XMG formalism and its implementation, and show how the latter makes it possible to extend the system relatively easily to different target formalisms, thus opening the way towards multi-formalism.Dans cet article, nous présentons une extension du système XMG (eXtensible MetaGrammar) afin de permettre la description de grammaires darbres adjoints à composantes multiples. Nous présentons en particulier le formalisme XMG et son implantation et montrons comment celle-ci permet relativement aisément détendre le système à différents formalismes grammaticaux cibles, ouvrant ainsi la voie au multi-formalisme
An Alternative Conception of Tree-Adjoining Derivation
The precise formulation of derivation for tree-adjoining grammars has
important ramifications for a wide variety of uses of the formalism, from
syntactic analysis to semantic interpretation and statistical language
modeling. We argue that the definition of tree-adjoining derivation must be
reformulated in order to manifest the proper linguistic dependencies in
derivations. The particular proposal is both precisely characterizable through
a definition of TAG derivations as equivalence classes of ordered derivation
trees, and computationally operational, by virtue of a compilation to linear
indexed grammars together with an efficient algorithm for recognition and
parsing according to the compiled grammar.Comment: 33 page
Tree-local MCTAG with shared nodes : an analysis of word order variation in German and Korean
Tree Adjoining Grammars (TAG) are known not to be powerful enough to deal with scrambling in free word order languages. The TAG-variants proposed so far in order to account for scrambling are not entirely satisfying. Therefore, an alternative extension of TAG is introduced based on the notion of node sharing. Considering data from German and Korean, it is shown that this TAG-extension can adequately analyse scrambling data, also in combination with extraposition and topicalization.Les Grammaires dArbres Adjoints (TAG) sont connues pour ne pas etre assez puissantes pour traiter le brouillage darguments dans des langues à ordre desmots libre. Les variantes TAG proposées jusqu´à maintenant pour expliquer le brouillage ne sont pas entièrement satisfaisantes. Nous présentons ici une extension alternative de TAG, basée sur la notion du partage de noeuds. En considerant des données de lallemand et du coréen, on montre que cette extension de TAG peut en juste proportion analyser des données de brouillage d’arguments, également en combinaison avec lextraposition et la topicalisation
Factoring Predicate Argument and Scope Semantics : underspecified Semantics with LTAG
In this paper we propose a compositional semantics for lexicalized tree-adjoining grammar (LTAG). Tree-local multicomponent derivations allow separation of the semantic contribution of a lexical item into one component contributing to the predicate argument structure and a second component contributing to scope semantics. Based on this idea a syntax-semantics interface is presented where the compositional semantics depends only on the derivation structure. It is shown that the derivation structure (and indirectly the locality of derivations) allows an appropriate amount of underspecification. This is illustrated by investigating underspecified representations for quantifier scope ambiguities and related phenomena such as adjunct scope and island constraints
Korean to English Translation Using Synchronous TAGs
It is often argued that accurate machine translation requires reference to
contextual knowledge for the correct treatment of linguistic phenomena such as
dropped arguments and accurate lexical selection. One of the historical
arguments in favor of the interlingua approach has been that, since it revolves
around a deep semantic representation, it is better able to handle the types of
linguistic phenomena that are seen as requiring a knowledge-based approach. In
this paper we present an alternative approach, exemplified by a prototype
system for machine translation of English and Korean which is implemented in
Synchronous TAGs. This approach is essentially transfer based, and uses
semantic feature unification for accurate lexical selection of polysemous
verbs. The same semantic features, when combined with a discourse model which
stores previously mentioned entities, can also be used for the recovery of
topicalized arguments. In this paper we concentrate on the translation of
Korean to English.Comment: ps file. 8 page
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