Submitted by Andrea Hayashi (deachan@gmail.com) on 2016-06-29T11:10:48Z No. of bitstreams: 1 dissertacao-daniel-soares-da-silva.pdf: 564662 bytes, checksum: 0e232e04bc33ddc0968cafb4cbb6d982 (MD5) / Approved for entry into archive by Andrea Hayashi (deachan@gmail.com) on 2016-06-29T11:13:30Z (GMT) No. of bitstreams: 1 dissertacao-daniel-soares-da-silva.pdf: 564662 bytes, checksum: 0e232e04bc33ddc0968cafb4cbb6d982 (MD5) / Made available in DSpace on 2016-06-29T11:13:30Z (GMT). No. of bitstreams: 1 dissertacao-daniel-soares-da-silva.pdf: 564662 bytes, checksum: 0e232e04bc33ddc0968cafb4cbb6d982 (MD5) Previous issue date: 2012-11-09 / Em janeiro de 1970, Saul Kripke proferiu três conferências na Universidade Princeton. A transcrição dessas conferências foi publicada em 1980 como Naming and Necessity. Nessa obra, Kripke critica o descritivismo, explicação então mais aceita para a função referencial dos nomes próprios, e apresenta a sua própria visão sobre o assunto. Em Naming and Necessity, Kripke também sustenta uma concepção que ficou conhecida como “essencialismo científico”, a qual afirma a existência de verdades necessárias a posteriori. Esta dissertação procura investigar de que maneira se relacionam as idéias sobre a referência e sobre o essencialismo científico no interior do pensamento kripkeano. Assim, no primeiro capítulo, procura-se apresentar as principais características do descritivismo. Em linhas gerais, a concepção descritivista, cujas origens remontam a certas idéias de Frege e Russell, estabelece que a explicação para a referência de um nome próprio passa pelas descrições associadas ao termo, as quais seriam satisfeitas univocamente pelo objeto designado. O segundo capítulo se ocupa dos argumentos kripkeanos contrários ao descritivismo. Esses argumentos são de três tipos: modal, epistêmico e semântico. A adequada compreensão desses argumentos, bem como do modelo explicativo alternativo proposto por Kripke, exige certos conceitos fundamentais, como o de mundos possíveis, a distinção entre modalidades epistêmicas e modalidades metafísicas, e o de designação rígida. Por isso, esse capítulo também busca expor tais noções. Finalmente, o terceiro capítulo é dedicado ao essencialismo científico desenvolvido por Kripke. Grosso modo, uma posição essencialista sustenta que os objetos possuem propriedades essenciais; isto é, propriedades que são exemplificadas em todos os mundos possíveis nos quais os objetos existem. O essencialismo científico afirma que cabe à ciência revelar essas propriedades essenciais, as quais seriam verdades necessárias a posteriori. O capítulo 3 examina o essencialismo quanto à origem biológica e aquele sobre a origem e composição material dos artefatos, além de outros aspectos relacionados ao tema discutidos por Kripke. / In January 1970, Saul Kripke delivered three lectures at Princeton University. A transcript of these lectures was published in 1980 as Naming and Necessity. In this work, Kripke criticizes descriptivism, then most accepted account for referential function of proper names, and presents his own view on the matter. In Naming and Necessity, Kripke also advocates a view that became known as “scientific essentialism”, which states that there are necessary a posteriori truths. This dissertation aims at understanding the relationship between Kripke’s view about reference and the scientific essentialism. Thus, in the first chapter, we expose the main features of descriptivism. In general, the descriptivist conception, whose origins go back to certain ideais of Frege and Russell, states that the explanation for the reference of a proper name is based on the descriptions associated with the name, which should be fulfilled only by designated object. The second chapter is concerned with Kripkean arguments against descriptivism. These arguments are of three types: modal, semantic and epistemic. A proper understanding of the arguments, as well as the alternative model proposed by Kripke, requires certain fundamental concepts, such as possible worlds, the distinction between epistemic modalities and metaphysical modalities, and the rigid designation. Therefore, the second chapter also intends to examine such notions. Finally, the third chapter turns to the scientific essentialism developed by Kripke. Roughly, an essentialist viewpoint holds that objects have essential properties. That is, properties that are exemplified in all possible worlds in which the objects exist. The scientific essentialism maintains that it is up to science to reveal the essential properties, which would be necessary a posteriori truths. The chapter 3 analyses the essentialism about biological origins and essentialism about the origin and composition of material artifacts, and other aspects related to the topic discussed by Kripke / TEDE

Made available in DSpace on 2015-07-22T20:50:42Z (GMT). No. of bitstreams: 0 Previous issue date: 2012-01-01. Added 1 bitstream(s) on 2015-08-11T03:26:32Z : No. of bitstreams: 1 Publico-DanielSoaresdaSilva.pdf: 576406 bytes, checksum: 27d43ce2592b4448856df105e09b7113 (MD5) / Em janeiro de 1970, Saul Kripke proferiu três conferências na Universidade Princeton. A transcrição dessas conferências foi publicada em 1980 como Naming and Necessity. Nessa obra, Kripke critica o descritivismo, explicação então mais aceita para a função referencial dos nomes próprios, e apresenta a sua própria visão sobre o assunto. Em Naming and Necessity, Kripke também sustenta uma concepção que ficou conhecida como “essencialismo científico”, a qual afirma a existência de verdades necessárias a posteriori. Esta dissertação procura investigar de que maneira se relacionam as idéias sobre a referência e sobre o essencialismo científico no interior do pensamento kripkeano. Assim, no primeiro capítulo, procura-se apresentar as principais características do descritivismo. Em linhas gerais, a concepção descritivista, cujas origens remontam a certas idéias de Frege e Russell, estabelece que a explicação para a referência de um nome próprio passa pelas descrições associadas ao termo, as quais seriam satisfeitas univocamente pelo objeto designado. O segundo capítulo se ocupa dos argumentos kripkeanos contrários ao descritivismo. Esses argumentos são de três tipos: modal, epistêmico e semântico. A adequada compreensão desses argumentos, bem como do modelo explicativo alternativo proposto por Kripke, exige certos conceitos fundamentais, como o de mundos possíveis, a distinção entre modalidades epistêmicas e modalidades metafísicas, e o de designação rígida. Por isso, esse capítulo também busca expor tais noções. Finalmente, o terceiro capítulo é dedicado ao essencialismo científico desenvolvido por Kripke. Grosso modo, uma posição essencialista sustenta que os objetos possuem propriedades essenciais; isto é, propriedades que são exemplificadas em todos os mundos possíveis nos quais os objetos existem. O essencialismo científico afirma que cabe à ciência revelar essas propriedades essenciais, as quais seriam verdades necessárias a posteriori. O capítulo 3 examina o essencialismo quanto à origem biológica e aquele sobre a origem e composição material dos artefatos, além de outros aspectos relacionados ao tema discutidos por Kripke. / In January 1970, Saul Kripke delivered three lectures at Princeton University. A transcript of these lectures was published in 1980 as Naming and Necessity. In this work, Kripke criticizes descriptivism, then most accepted account for referential function of proper names, and presents his own view on the matter. In Naming and Necessity, Kripke also advocates a view that became known as “scientific essentialism”, which states that there are necessary a posteriori truths. This dissertation aims at understanding the relationship between Kripke’s view about reference and the scientific essentialism. Thus, in the first chapter, we expose the main features of descriptivism. In general, the descriptivist conception, whose origins go back to certain ideais of Frege and Russell, states that the explanation for the reference of a proper name is based on the descriptions associated with the name, which should be fulfilled only by designated object. The second chapter is concerned with Kripkean arguments against descriptivism. These arguments are of three types: modal, semantic and epistemic. A proper understanding of the arguments, as well as the alternative model proposed by Kripke, requires certain fundamental concepts, such as possible worlds, the distinction between epistemic modalities and metaphysical modalities, and the rigid designation. Therefore, the second chapter also intends to examine such notions. Finally, the third chapter turns to the scientific essentialism developed by Kripke. Roughly, an essentialist viewpoint holds that objects have essential properties. That is, properties that are exemplified in all possible worlds in which the objects exist. The scientific essentialism maintains that it is up to science to reveal the essential properties, which would be necessary a posteriori truths. The chapter 3 analyses the essentialism about biological origins and essentialism about the origin and composition of material artifacts, and other aspects related to the topic discussed by Kripke. / TEDE

Atmospheric mountain waves form in the lee of mountainous terrain under appropriate conditions of the vertical structure of wind speed and atmospheric stability. Trapped lee waves can extend hundreds of kilometers downwind from the mountain range, and they can extend tens of kilometers vertically into the stratosphere. Mountain waves are of importance in meteorology as they affect the general circulation of the atmosphere, can influence the vertical structure of wind speed and temperature fields, produce turbulence and downdrafts that can be an aviation hazard, and affect the vertical transport of aerosols and trace gasses, and ozone concentration. Sailplane pilots make extensive use of mountain lee waves as a source of energy with which to climb. There are many sailplane wave flights conducted every year throughout the world and they frequently cover large distances and reach high altitudes. Modern sailplanes frequently carry flight recorders that record their position at regular intervals during the flight. There is therefore potential to use this recorded data to determine the 3D wind velocity at positions on the sailplane flight path. This would provide an additional source of information on mountain waves to supplement other measurement techniques that might be useful for studies on mountain waves. The recorded data are limited however, and determination of wind velocities is not straightforward. This thesis is concerned with the development and application of techniques to determine the vector wind field in atmospheric mountain waves using the limited flight data collected during sailplane flights. A detailed study is made of the characteristics, uniqueness, and sensitivity to errors in the data, of the problem of estimating the wind velocities from limited flight data consisting of ground velocities, possibly supplemented by air speed or heading data. A heuristic algorithm is developed for estimating 3D wind velocities in mountain waves from ground velocity and air speed data, and the algorithm is applied to flight data collected during “Perlan Project” flights. The problem is then posed as a statistical estimation problem and maximum likelihood and maximum a posteriori estimators are developed for a variety of different kinds of flight data. These estimators are tested on simulated flight data and data from Perlan Project flights.

Ce travail est consacré à l’étude d’estimateurs d'erreur a posteriori de type flux équilibrés et résiduels pour la résolution des équations de Reissner-Mindlin par la méthode des éléments finis. Le mémoire débute par l'introduction du problème aux limites et de son analyse de convergence a priori par la méthode des éléments finis. Nous construisons alors pour une discrétisation conforme un estimateur a posteriori de type flux équilibrés fiable, efficace et robuste en l'épaisseur de la plaque t. Nous obtenons finalement une constante multiplicative égale à 1 pour la fiabilité. Des tests numériques illustrent nos résultats pour différents maillages. Puis nous abordons le cas d’une discrétisation non-conforme, où nous proposons un estimateur a posteriori de type résiduel, utilisant une régularisation de la solution discrète. Des tests numériques illustrent également nos résultats. La suite du travail reprend la discrétisation conforme en construisant un estimateur a posteriori défini à partir de la résolution de problèmes localisés sur les patchs de la triangulation, menant à un choix plus consistant avec le problème aux limites. Le dernier chapitre est consacré à l'estimation a posteriori pour le problème aux valeurs propres de Reissner-Mindlin. L’estimateur obtenu est fiable et efficace pour la norme de l'erreur entre les vecteurs propres, permettant également de majorer l’erreur commise entre les valeurs propres. Des tests numériques illustrent nos résultats. / This work is devoted to the study of equilibrated fluxes and residual a posteriori error estimators for the finite element resolution of the Reissner-Mindlin system. This report begins by the introduction of the boundary value problem and of its a priori convergence analysis in the finite element method context. Then, an equilibrated fluxes a posteriori estimator is built for a conform discretization, which is proven to be reliable, efficient and robust on the plate thickness t. We finally obtain a multiplicative constant equal to 1 for the reliability. Numerical tests illustrate our results on different meshes. Then, we address the non-conforming discretization case, where a residual a posteriori estimator is proposed using a regularisation of the discrete solution. Numerical tests also illustrate our results. Next we come back to the conform discretization by building an a posteriori estimator defined from localised problems resolution on stars, leading to a consistent choice with the boundary value problem. The last chapter is devoted to an a posteriori estimation for the Reissner-Mindlin eigenvalues problem. The obtained estimator is reliable and efficient for the error norm between the eigenvectors, also allowing to evaluate the error between the eigenvalues. Numerical tests illustrate our results.

We present a method for Poisson’s equation that computes guaranteed upper and lower bounds for the values of linear functional outputs of the exact weak solution of the infinite dimensional continuum problem using traditional finite element approximations. The guarantee holds uniformly for any level of refinement, not just in the asymptotic limit of refinement. Given a finite element solution and its output adjoint solution, the method can be used to provide a certificate of precision for the output with an asymptotic complexity which is linear in the number of elements in the finite element discretization. / Singapore-MIT Alliance (SMA)

We present a technique for the rapid and reliable prediction of linear-functional outputs of elliptic (and parabolic) partial differential equations with affine parameter dependence. The essential components are (i) (provably) rapidly convergent global reduced-basis approximations -- Galerkin projection onto a space WN spanned by solutions of the governing partial differential equation at N selected points in parameter space; (ii) a posteriori error estimation -- relaxations of the error-residual equation that provide inexpensive yet sharp and rigorous bounds for the error in the outputs of interest; and (iii) off-line/on-line computational procedures -- methods which decouple the generation and projection stages of the approximation process. The operation count for the on-line stage -- in which, given a new parameter value, we calculate the output of interest and associated error bound -- depends only on N (typically very small) and the parametric complexity of the problem; the method is thus ideally suited for the repeated and rapid evaluations required in the context of parameter estimation, design, optimization, and real-time control. / Singapore-MIT Alliance (SMA)

Dans une première partie, on introduit des estimateurs d'erreur a posteriori pour l'équation de la chaleur<br />dans R^d, d=2,3 via une méthode d'éléments finis non conformes en espace et un schéma d'Euler implicite en temps. Pour cette discrétisation, on élabore un indicateur d'erreur résiduel spatial basé sur les sauts des dérivées normales et tangentielles de notre approximation, ainsi qu'un indicateur résiduel temporel basé sur le saut du gradient à chaque pas de temps. Les bornes inférieures et supérieures de la norme de l'erreur forment les résultats principaux de cette étude. En outre, on montre que ces estimateurs sont fiables et efficaces. Dans une seconde partie, on traite le problème de Stokes dynamique. L'élaboration des estimateurs a posteriori est également basée sur des estimateurs spatiaux et temporels. Une preuve de leur fiabilité et de leur efficacité est donnée. Finalement, les tests numériques et un algorithme adaptatif confirment les prévisions théoriques et le bon comportement de ces estimateurs.

Zugl.: Berlin, Techn. Univ., Diss., 2000 / Hergestellt on demand

University, Diss., 2003--Heidelberg.

Universiẗat, Diss., 2003--Kiel.