373 resultados para eta invariant

em Archivo Digital para la Docencia y la Investigación - Repositorio Institucional de la Universidad del País Vasco


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In this thesis we propose a new approach to deduction methods for temporal logic. Our proposal is based on an inductive definition of eventualities that is different from the usual one. On the basis of this non-customary inductive definition for eventualities, we first provide dual systems of tableaux and sequents for Propositional Linear-time Temporal Logic (PLTL). Then, we adapt the deductive approach introduced by means of these dual tableau and sequent systems to the resolution framework and we present a clausal temporal resolution method for PLTL. Finally, we make use of this new clausal temporal resolution method for establishing logical foundations for declarative temporal logic programming languages. The key element in the deduction systems for temporal logic is to deal with eventualities and hidden invariants that may prevent the fulfillment of eventualities. Different ways of addressing this issue can be found in the works on deduction systems for temporal logic. Traditional tableau systems for temporal logic generate an auxiliary graph in a first pass.Then, in a second pass, unsatisfiable nodes are pruned. In particular, the second pass must check whether the eventualities are fulfilled. The one-pass tableau calculus introduced by S. Schwendimann requires an additional handling of information in order to detect cyclic branches that contain unfulfilled eventualities. Regarding traditional sequent calculi for temporal logic, the issue of eventualities and hidden invariants is tackled by making use of a kind of inference rules (mainly, invariant-based rules or infinitary rules) that complicates their automation. A remarkable consequence of using either a two-pass approach based on auxiliary graphs or aone-pass approach that requires an additional handling of information in the tableau framework, and either invariant-based rules or infinitary rules in the sequent framework, is that temporal logic fails to carry out the classical correspondence between tableaux and sequents. In this thesis, we first provide a one-pass tableau method TTM that instead of a graph obtains a cyclic tree to decide whether a set of PLTL-formulas is satisfiable. In TTM tableaux are classical-like. For unsatisfiable sets of formulas, TTM produces tableaux whose leaves contain a formula and its negation. In the case of satisfiable sets of formulas, TTM builds tableaux where each fully expanded open branch characterizes a collection of models for the set of formulas in the root. The tableau method TTM is complete and yields a decision procedure for PLTL. This tableau method is directly associated to a one-sided sequent calculus called TTC. Since TTM is free from all the structural rules that hinder the mechanization of deduction, e.g. weakening and contraction, then the resulting sequent calculus TTC is also free from this kind of structural rules. In particular, TTC is free of any kind of cut, including invariant-based cut. From the deduction system TTC, we obtain a two-sided sequent calculus GTC that preserves all these good freeness properties and is finitary, sound and complete for PLTL. Therefore, we show that the classical correspondence between tableaux and sequent calculi can be extended to temporal logic. The most fruitful approach in the literature on resolution methods for temporal logic, which was started with the seminal paper of M. Fisher, deals with PLTL and requires to generate invariants for performing resolution on eventualities. In this thesis, we present a new approach to resolution for PLTL. The main novelty of our approach is that we do not generate invariants for performing resolution on eventualities. Our method is based on the dual methods of tableaux and sequents for PLTL mentioned above. Our resolution method involves translation into a clausal normal form that is a direct extension of classical CNF. We first show that any PLTL-formula can be transformed into this clausal normal form. Then, we present our temporal resolution method, called TRS-resolution, that extends classical propositional resolution. Finally, we prove that TRS-resolution is sound and complete. In fact, it finishes for any input formula deciding its satisfiability, hence it gives rise to a new decision procedure for PLTL. In the field of temporal logic programming, the declarative proposals that provide a completeness result do not allow eventualities, whereas the proposals that follow the imperative future approach either restrict the use of eventualities or deal with them by calculating an upper bound based on the small model property for PLTL. In the latter, when the length of a derivation reaches the upper bound, the derivation is given up and backtracking is used to try another possible derivation. In this thesis we present a declarative propositional temporal logic programming language, called TeDiLog, that is a combination of the temporal and disjunctive paradigms in Logic Programming. We establish the logical foundations of our proposal by formally defining operational and logical semantics for TeDiLog and by proving their equivalence. Since TeDiLog is, syntactically, a sublanguage of PLTL, the logical semantics of TeDiLog is supported by PLTL logical consequence. The operational semantics of TeDiLog is based on TRS-resolution. TeDiLog allows both eventualities and always-formulas to occur in clause heads and also in clause bodies. To the best of our knowledge, TeDiLog is the first declarative temporal logic programming language that achieves this high degree of expressiveness. Since the tableau method presented in this thesis is able to detect that the fulfillment of an eventuality is prevented by a hidden invariant without checking for it by means of an extra process, since our finitary sequent calculi do not include invariant-based rules and since our resolution method dispenses with invariant generation, we say that our deduction methods are invariant-free.

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[Es]El presente trabajo se basa en las consultas que los profesores y profesoras de distintas asignaturas nos hacen al profesorado de lengua. Muchas veces los profesores debemos corregir no sólo el contenido de los trabajos de nuestros alumnos, sino también la lengua. La discusión no es nueva: ¿somos todos los profesores también profesores de lengua? Es un desafío del que difícilmente podemos escapar, ya que la lengua además de ser una materia de estudio también es el vehículo en el que se imparten los contenidos de todas las asignaturas. Con el presente trabajo pretendemos ayudar a los profesores que no imparten lengua como asignatura a corregir los trabajos de sus alumnos. Esta propuesta consta de tres ejes de actuación marcados por un orden de prioridad: prevenir, autocorregir y ayudar.

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Duración (en horas): De 31 a 40 horas. Nivel educativo: Grado

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Duración (en horas): De 21 a 30 horas. Nivel educativo: Grado

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383 p. ; P.315-383: "Erauso Kateriñe" antzezlanaren edizioa dago.

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We completely classify constant mean curvature hypersurfaces (CMC) with constant δ-invariant in the unit 4-sphere S4 and in the Euclidean 4-space E4.

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[EN] This paper examines the syntactic ideas of Pablo Pedro Astarloa (1752-1806) as he explained in his Discursos filosóficos sobre la lengua primitiva (1805), and tries to put them in the context of the debate between rationalists and sensualists, who argued whether there is a «natural order» of words. Astarloa developed a system for accounting the word order in the primitive language of mankind (and hence in the Basque language) founded in three types of «nobleness», and in the principle that the noblest element precedes the less noble one. The first type (nobleza de origen) orders words according to their meaning. The second type (nobleza de ministerio) orders words according to the part of speech they belong to, or the semantic function they have. Finally, the third type (nobleza de mérito or de movilidad) considers the will for communication and, as a result, word order reflects the information structure. Moreover Astarloa ’s three types of nobleness are arranged in a hierarchy of superiority: movilidad > ministerio > origen. So Astarloa ’s syntax appears near to sensualists ’ conceptions on word order because it did not appeal for a fixed natural order of words; instead he proposed a variable word order based mainly on the communicative process.

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Astarloa's Discursos filosóficos is the most extensive and detailed apology of the Basque language as the first language of mankind. The text was finished in 1805 but the first edition was published in 1883. In this paper I attempt to sketch the main linguistic and philosophic ideas that could have an influence in Astarloa's thought. Then I deal with Astarloa's characterization of the first language, and the three principles he used to verify that Basque was that first language of human beings.

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[EN] In this paper I offer a new edition of the Euskera manuscript, written by the bascologist J.F. Aizkibel in 1856. The preliminary study focuses on a survey of the sources extensively used by Aizkibel, which are mainly two: Schleicher's Die Sprachen Europas (1850 [1852]) and Champollion-Figeac's Égypte ancienne (1840). Moreover, the comparison with the sources reveals us that Aizkibel intended to adapt Schleicher’s and Champollion-Figeac's analyses to attest that Basque was originally a very ancient monosyllabic language, and that it was spoken by cultured people. Some other linguistic ideas of Aizkibel are also discussed.

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[ES]Hoy en día, la linea de investigación sobre la detección de rostros se ha incrementado, debido al uso y la influencia del mismo en diferentes aplicaciones. Por ejemplo, la mayoría de las cámaras digitales actuales, para mejorar la claridad de la imagen y la focalización, tienen incorporado un sistema de detección del rostro. La detección del rostro también es el primer paso para otras aplicaciones y lineas de investigación, como pueden ser el seguimiento de los ojos, y la vigilancia de la seguridad de varias aplicaciones, entre otros. Por esta razón, es necesario realizar una correcta detección facial. En esta tesis de máster, se realizará un análisis y estudio del estado del arte de la detección del rostro, para posteriormente realizar una aplicación práctica, así como su validación y análisis. El detector desarrollado es la conjunción del uso de diferentes cascadas de clasificadores basados en el método de Viola y Jones y las características de Lienhart, y un detector de piel.

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Traducido por Iñaki Villoslada Fernández