Results 1  10
of
23
Artificial Intelligence: A Computational Perspective
 Essentials in Knowledge Representation
, 1994
"... Although the computational perspective on cognitive tasks has always played a major role in Artificial Intelligence, the interest in the precise determination of the computational costs that are required for solving typical AI problems has grown only recently. In this paper, we will describe what in ..."
Abstract

Cited by 32 (1 self)
 Add to MetaCart
Although the computational perspective on cognitive tasks has always played a major role in Artificial Intelligence, the interest in the precise determination of the computational costs that are required for solving typical AI problems has grown only recently. In this paper, we will describe what insights a computational complexity analysis can provide and what methods are available to deal with the complexity problem. This work was partially supported by the European Commission as part of DRUMSII, the ESPRIT Basic Research Project P6156. 1 Introduction It is wellknown that typical AI problems, such as natural language understanding, scene interpretation, planning, configuration, or diagnosis are computationally difficult. Hence, it seems to be worthless to analyze the computational complexity of these problems. In fact, some people believe that all AI problems are NPhard or even undecidable. Conceiving AI as a scientific field that has as its goal the analysis and synthesis of...
Formalisms For Morphographemic Description
, 1987
"... Recently there has been some interest in rule formalisms for describing morphologically significant regularities in orthography of words, largely influenced by the work of Koskenniemi. Various implementations of these rules are possible, but there are some weaknesses in the formalism as it stands. A ..."
Abstract

Cited by 22 (3 self)
 Add to MetaCart
Recently there has been some interest in rule formalisms for describing morphologically significant regularities in orthography of words, largely influenced by the work of Koskenniemi. Various implementations of these rules are possible, but there are some weaknesses in the formalism as it stands. An alternative specification formalism is possible which solves some of the problems. This new formalism can be viewed as a variant of the "pure" Koskenniemi model with certain constraints relaxed. The new formalism has particular advantages for multiple character changes. An interpreter has been implemented for the formalism and a significant subset of English morphographemics has been described, but it has yet to be used for describing other languages. Background This paper describes work in a particular area of computational morphology, that of morphographemics. Morphographemics is the area dealing with systematic discrepancies between the surface form of words and the symbolic represent...
Systematic Parameterized Complexity Analysis in Computational Phonology
, 1999
"... Many computational problems are NPhard and hence probably do not have fast, i.e., polynomial time, algorithms. Such problems may yet have nonpolynomial time algorithms, and the nonpolynomial time complexities of these algorithms will be functions of particular aspects of that problem, i.e., the a ..."
Abstract

Cited by 18 (3 self)
 Add to MetaCart
(Show Context)
Many computational problems are NPhard and hence probably do not have fast, i.e., polynomial time, algorithms. Such problems may yet have nonpolynomial time algorithms, and the nonpolynomial time complexities of these algorithms will be functions of particular aspects of that problem, i.e., the algorithm's running time is upper bounded by f(k)jxj c where f is an arbitrary function, jxj is the size of the input x to the algorithm, k is an aspect of the problem, and c is a constant independent of jxj and k. Given such algorithms, it may still be possible to obtain optimal solutions for large instances of NPhard problems for which the appropriate aspects are of small size or value. Questions about the existence of such algorithms are most naturally addressed within the theory of parameterized computational complexity developed by Downey and Fellows. This thesis considers the merits of a systematic parameterized complexity analysis in which results are derived relative to all subsets of a specied set of aspects of a given NPhard problem. This set of results denes an \intractability map " that shows relative to
Planar Phonology and Morphology
, 1991
"... The development of the nonlinear theory of phonological representation has lent great depth to our current understanding of longdistance phonological processes like harmony, and in particular to our understanding of transparent and opaque segments in harmony systems. This thesis argues for an ana ..."
Abstract

Cited by 17 (0 self)
 Add to MetaCart
The development of the nonlinear theory of phonological representation has lent great depth to our current understanding of longdistance phonological processes like harmony, and in particular to our understanding of transparent and opaque segments in harmony systems. This thesis argues for an analysis of harmony systems in which the properties of transparency and opacity are not primitive, but instead derive from properties of the phonological representation to which harmony applies. Blocking segments can be characterized either by their specification for the harmonic feature, or in cases of parasitic harmony, by their specification for a contextual feature on which harmony is dependent. Central to this analysis is the idea that all phonological processes are governed by a locality constraint which requires that two elements related in a phonological rule be adjacent at some level in the phonological representation. The harmony rules of four languages are examined in detail; these rules
XUXEN: A Spelling Checker/Corrector for Basque Based on TwoLevel Morphology
, 1992
"... The application of the formalism of twolevel morphology to Basque and its use in the elaboration of the XUXEN spelling checker/corrector are described. This application is intended to cover a large part of the language. Because Basque is a highly inflected language, the approach of spelling checkin ..."
Abstract

Cited by 7 (4 self)
 Add to MetaCart
The application of the formalism of twolevel morphology to Basque and its use in the elaboration of the XUXEN spelling checker/corrector are described. This application is intended to cover a large part of the language. Because Basque is a highly inflected language, the approach of spelling checking and correction has been conceived as a byproduct of a general purpose morphological analyzer/generator. This analyzer is taken as a basic tool for current and future work on automatic processing of Basque. An extension for continuation class specifications in order to deal with longdistance dependencies is proposed. This extension consists basically of two features added to the standard formalism which allow the lexicon builder to make explicit the interdependencies of morphemes. Userlexicons can be interactively enriched with new entries enabling the checker from then on to recognize all the possible flexions derived from them. Due to a late process of standardization of the language, ...
Feature unification for morphological parsing in Bangla
 In Proceeding .of International Conference on Computer and Information Technology
, 2004
"... This paper describes a Feature Unification Based Word Grammar model for the morphological parsing of Bangla words. While normal morphological parsing strategy is adequate to decompose a word into morphemes, it is not able directly to compute the part of speech of a derivationally complex word or ret ..."
Abstract

Cited by 5 (2 self)
 Add to MetaCart
This paper describes a Feature Unification Based Word Grammar model for the morphological parsing of Bangla words. While normal morphological parsing strategy is adequate to decompose a word into morphemes, it is not able directly to compute the part of speech of a derivationally complex word or return a word's inflectional featuresprecisely the information required for syntactic parsing. These deficiencies have now been remedied by adding a unificationbased word grammar component which can provide parse trees and feature structures. In addition to that, feature unification lessens the number of lexicon classes (less space) and actually reduces the complexities regarding morphotactic analysis.
A TwoLevel Morphological Analysis of Korean
, 1994
"... this paper, wc show that the lwodcvcl model eau bc aucccasJlly plied lo Korcau and its rule size ia limited to ouly 52. An cxtcnsiou of twolevel morpholoyy is described for Korean lan.quagc ..."
Abstract

Cited by 4 (0 self)
 Add to MetaCart
this paper, wc show that the lwodcvcl model eau bc aucccasJlly plied lo Korcau and its rule size ia limited to ouly 52. An cxtcnsiou of twolevel morpholoyy is described for Korean lan.quagc
Learning Morphology  Practice Makes Good
 Grammatical Inference and Applications, Second International Colloquium, ICGI94
, 1994
"... Abstract A model for learning morphological transformations is given. The model is based upon Koskenniemi's Two Level Morphology model. It is shown that while the number of examples required for learning is polynomial, the computational problem associated with learning is intractable. Learning ..."
Abstract

Cited by 3 (0 self)
 Add to MetaCart
(Show Context)
Abstract A model for learning morphological transformations is given. The model is based upon Koskenniemi's Two Level Morphology model. It is shown that while the number of examples required for learning is polynomial, the computational problem associated with learning is intractable. Learning homomorphisms is a simple special case of the general model. While a general method for learning homomorphisms is not known, it is shown that even if the target language is over a single letter alphabet, learning within the minimum number of examples is computationally intractable. If, however, additional examples are given, learning can be achieved in time polynomial in the size of the morphological transformation. 1 Introduction In linguistics, morphology is the theory of the construction of words. Words are constructed from more basic units called morphemes. To construct a word the appropriate morphemes are concatenated then morphological transformations are applied to yield the final form. ...