142 research outputs found
An automata characterisation for multiple context-free languages
We introduce tree stack automata as a new class of automata with storage and
identify a restricted form of tree stack automata that recognises exactly the
multiple context-free languages.Comment: This is an extended version of a paper with the same title accepted
at the 20th International Conference on Developments in Language Theory (DLT
2016
A linear time extension of deterministic pushdown automata
Proceedings of the 17th Nordic Conference of Computational Linguistics
NODALIDA 2009.
Editors: Kristiina Jokinen and Eckhard Bick.
NEALT Proceedings Series, Vol. 4 (2009), 182-189.
© 2009 The editors and contributors.
Published by
Northern European Association for Language
Technology (NEALT)
http://omilia.uio.no/nealt .
Electronically published at
Tartu University Library (Estonia)
http://hdl.handle.net/10062/9206
Two characterisation results of multiple context-free grammars and their application to parsing
In the first part of this thesis, a Chomsky-SchĂŒtzenberger characterisation and an automaton characterisation of multiple context-free grammars are proved. Furthermore, a framework for approximation of automata with storage is described. The second part develops each of the three theoretical results into a parsing algorithm
An earley parsing algorithm for range concatenation grammars
We present a CYK and an Earley-style algorithm for parsing Range Concatenation Grammar (RCG), using the deductive parsing framework. The characteristic property of the Earley parser is that we use a technique of range boundary constraint propagation to compute the yields of non-terminals as late as possible. Experiments show that, compared to previous approaches, the constraint propagation helps to considerably decrease the number of items in the chart
A declarative characterization of different types of multicomponent tree adjoining grammars
Multicomponent Tree Adjoining Grammars (MCTAGs) are a formalism that has been shown to be useful for many natural language applications. The definition of non-local MCTAG however is problematic since it refers to the process of the derivation itself: a simultaneity constraint must be respected concerning the way the members of the elementary tree sets are added. Looking only at the result of a derivation (i.e., the derived tree and the derivation tree), this simultaneity is no longer visible and therefore cannot be checked. I.e., this way of characterizing MCTAG does not allow to abstract away from the concrete order of derivation. In this paper, we propose an alternative definition of MCTAG that characterizes the trees in the tree language of an MCTAG via the properties of the derivation trees (in the underlying TAG) the MCTAG licences. We provide similar characterizations for various types of MCTAG. These characterizations give a better understanding of the formalisms, they allow a more systematic comparison of different types of MCTAG, and, furthermore, they can be exploited for parsing
Un algorithme d'analyse de type earley pour grammaires à concaténation d'intervalles
Nous prĂ©sentons ici diffĂ©rents algorithmes dâanalyse pour grammaires Ă concatĂ©nation dâintervalles (Range Concatenation Grammar, RCG), dont un nouvel algorithme de type Earley, dans le paradigme de lâanalyse dĂ©ductive. Notre travail est motivĂ© par lâintĂ©rĂȘt portĂ© rĂ©cemment Ă ce type de grammaire, et comble un manque dans la littĂ©rature existante.We present several different parsing algorithms for Range Concatenation Grammar (RCG), inter alia an entirely novel Earley-style algorithm, using the deductive parsing framework. Our work is motivated by recent interest in range concatenation grammar in general and fills a gap in the existing literature
Programming Language Techniques for Natural Language Applications
It is easy to imagine machines that can communicate in natural language. Constructing such machines is more difficult. The aim of this thesis is to demonstrate
how declarative grammar formalisms that distinguish between abstract and concrete syntax make it easier to develop natural language applications.
We describe how the type-theorectical grammar formalism Grammatical
Framework (GF) can be used as a high-level language for natural language
applications. By taking advantage of techniques from the field of programming
language implementation, we can use GF grammars to perform portable
and efficient parsing and linearization, generate speech recognition language
models, implement multimodal fusion and fission, generate support code for
abstract syntax transformations, generate dialogue managers, and implement
speech translators and web-based syntax-aware editors.
By generating application components from a declarative grammar, we can
reduce duplicated work, ensure consistency, make it easier to build multilingual
systems, improve linguistic quality, enable re-use across system domains, and
make systems more portable
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