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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Estudo "In Vitro" da lisura da superfície das ligas de titânio e níquel-cromo, submetidas à ciclagem térmica em intervalos de tempo, com a utilização da rugosimetria. / "In vitro" study of the surface smoothness of two kinds of alloys - titanium and nickel - chromium, submitted to thermo cycling at intervals, through rugosimetry.

Wilson Tavares de Oliveira Junior 31 August 2000 (has links)
A capacidade de resistência à corrosão sofrida pelas próteses dentais confeccionadas com ligas metálicas é de grande importância na clínica odontológica devido à ocorrência de possíveis reações biológicas, como por exemplo, sintomas alérgicos e degradação das restaurações. Em razão da presença de fatores diversos agindo no meio oral, todo material restaurador, metálico ou não, sofre uma ação de deterioração em sua superfície, seja por variação de pH, dieta alimentar, temperatura ou mastigação. Houve evolução de novas ligas metálicas, entre elas o titânio (Ti), que apresenta propriedades físicas e biocompatíveis excelentes, sendo um material muito utilizado em vários setores relacionados à área odontológica, principalmente na indústria de implantes dentais. Nesse estudo foi avaliada a rugosidade superficial de duas ligas metálicas (Ti e Ni Cr ) em três fases distintas, através de leituras realizadas pelo rugosímetro de superfície nos corpos de prova, submetidos à ciclagem térmica e submersos em saliva artificial à temperatura constante de 37 graus centígrados, por um período de 8 meses. Através dos resultados estatísticos obtidos, conclui-se que não existe diferença entre as ligas, no tocante aos fatores tempo e aspecto visual, havendo somente diferença significante entre as fases I e III do estudo. / The resistance capacity to corrosion to which the dental prosthesis made in mettalic alloys are subject has a major importance in the dental clinic, due to the occurance of possible biological reactions such as, for example, allergic symptoms and degradation of restorations. As there are several factors acting in the oral medium, every restoration material, either metallic or not, is subject to a deterioration action in its surface, caused by pH variation, alimentary diet, temperature and chewing. New metallic alloys have been developed, among them the Titanium (Ti), which presents excellent acceptance in the dentistry area , mainly in the industry of dental implants. This study appraised the superficial rugosity of two metallic alloys Titanium e Nickel Chromium (Ni Cr) in three different phases , through readings made by the surface rugosimeter in the test bodies, submitted to thermal cycling and submerged in artificial saliva at constant temperature of 37 degrees, for a period of 8 months. Through the achieved statistic results, it may be concluded that there is no difference between the alloys, concerning the time and visual aspect factors, there being a significant difference only between phases I and III of the study.
32

EFEITO DO REPOLIMENTO APÓS CLAREAMENTO NA ESTABILIDADE DE COR E RUGOSIDADE DE RESINAS COMPOSTAS / EFFECT OF REPOLISHING AFTER BLEACHING ON COLOR STABILITY AND ROUGHNESS OF COMPOSITE RESINS

Rodrigues, Camila da Silva 15 July 2016 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This study aimed to evaluate the effect of repolishing after bleaching on color stability and roughness of two composite resins aged in high staining beverage. Sixty-one disc-shaped specimens (8 mm diameter x 2 mm thickness) of each composite resin were fabricated (microhybrid vs. nanoparticle), then divided according to treatment: bleached or non-bleached. After bleaching phase, groups were subdivided according to surface treatment, repolished or unrepolished, using extrafine sandpaper discs and felt with diamond paste. A new subdivision was performed according to aging conditions: immersion in red wine 15 min/day or in artificial saliva 24 h/day during 30 days. Color (CIE L*a*b* system) and roughness (Ra) were assessed at baseline (P0), after bleaching procedures (P1), after surface treatment (P2) and after aging (P3). Color change (ΔE00) was calculated with CIEDE2000 formula. One specimen per group was removed from each study phase, in order to be analyzed in Scanning Electron Microscope (SEM). Statistical analysis was performed using repeated measures ANOVA and Tukey s test as post-hoc (significance level was set at 5%). Bleached repolished groups presented lower color alteration than the bleached unrepolished groups of both composite resins when aged in red wine. Repolishing (P1 vs. P2) promoted a decrease in roughness values of almost all groups. Nanoparticle resin presented greater ΔE00 values than microhybrid one when aged in red wine. SEM images reveled more porosities in bleached unrepolished groups. Therefore, repolishing immediately after bleaching improves color stability of composite resins when exposed to staining agents, and it is capable to improve smoothness. / Este trabalho avaliou o efeito do repolimento após clareamento na estabilidade de cor e na rugosidade de duas resinas compostas ao serem expostas à solução de alto potencial pigmentante. Foram confeccionados 61 corpos de prova em forma de disco (8 mm diâmetro x 2 mm espessura) de cada resina (microhíbrida vs. nanoparticulada), que foram divididos conforme tratamento recebido: clareados ou não clareados. Após, os grupos foram subdivididos de acordo com o tratamento de superfície, com repolimento ou sem repolimento, usando discos de lixa na granulação extrafina e feltro com pasta diamantada extrafina. Nova subdivisão foi realizada baseada no meio de armazenamento: 15 min/dia em vinho tinto ou 24 h/dia em saliva artificial durante 30 dias. Sucessivas leituras de cor e rugosidade (Ra) foram efetuadas após 24 h da confecção dos cps (P0), após tratamento clareador (P1), após tratamento de superfície (P2) e após imersão (P3). A alteração de cor (ΔE00) foi calculada pela equação CIEDE2000. Em cada fase do estudo, um corpo de prova de cada grupo foi removido e analisado por microscopia eletrônica de varredura (MEV). A análise estatística foi realizada pelo Teste de Análise de Variância para medidas repetidas seguido do Teste de Tukey como post-hoc (nível de significância de 5%). Os grupos clareados repolidos apresentaram menor alteração de cor que os grupos clareados não repolidos das duas resinas compostas quando imersas em vinho tinto. O repolimento (P2 vs. P1) promoveu diminuição dos valores de rugosidade de quase todos os grupos. A resina nanoparticulada apresentou valores maiores de alteração de cor que a resina microhíbrida nos grupos imersos em vinho. As imagens de MEV mostraram maior número de porosidades nos grupos clareados não repolidos. Portanto, o repolimento imediatamente após o clareamento aumenta a estabilidade de cor de resinas compostas quando há contato com agentes corantes, e também pode diminuir a rugosidade desses materiais.
33

Temperature Robust Longwave Infrared Hyperspectral Change Detection

Durkee, Nicholas A. January 2018 (has links)
No description available.
34

Inverkan av uppmärksamhetsfokus på utförandet av knäböj på vippbräda : med jämförelse mellan personer med främre korsbandsrekonstruktion och personer utan knäskada / The influence of attentional focus on performance of squats on a rockerboard : with comparison between persons with ACL-reconstruction and persons without knee injury

Kallin, Jesper, Kallings, Oscar January 2023 (has links)
Bakgrund: Uppmärksamhetsfokus på omgivningen/externt fokus har återkommande visat förbättra motorisk färdighet, inlärning och prestation under flertalet olika motoriska uppgifter i jämförelse med fokus på egna kroppen/internt fokus. Instruktioner som uppmuntrar till internt fokus är mer förekommande vid rehabiliteringen av skador som ruptur av främre korsbandet, däremot har externt fokus visats påverka kinematiska variabler som kan minska risken för återskada. Uppmärksamhetsfokus inverkan på kinematiken under knäböj på vippbräda har dock inte studerats tidigare. Syfte: Syftet var att undersöka om instruktioner som uppmuntrar olika uppmärksamhetsfokus har en inverkan på uförande mätt som rörelseflyt, knästabilitet och balans under ett knäböj på vippbräda samt om det fanns skillnader i utförande mellan personer utan knäskada och personer med främre korsbandsrekonstruktion (ACLr). Metod: Sexton deltagare (11 icke-skadade, 5 ACLr) genomförde sex knäböj på en vippbräda under tre omgångar med instruktioner som uppmuntrade till antingen inget särskilt fokus (neutralt), externt fokus (på vippbrädan) eller internt fokus (på fötterna). Alla knäböj registrerades med ett tredimensionellt kamerasystem. Neutralt fokus utfördes först följt av externt eller internt fokus i randomiserad ordning. Utfallsvariabeln rörelseflyt mättes som avvikelser i knäböjets hastighetskurva, knästabilitet som adduktion/abduktion av underbenet och balans som brädans avvikande lutning i horisontalplan. Resultat: Internt fokus ledde till signifikant mindre knäadduktion (gruppmedian skillnad 1.9°) under flexionsfasen när man slog ihop alla 16 deltagare jämfört med neutralt fokus. Inga andra signifikanta resultat noterades mellan uppmärksamhetsfokus eller mellan grupperna utifrån utfallsvariablerna.   Slutsats: Uppmärksamhetsfokus hade ingen konsekvent inverkan på rörelseflyt, balans och knästabilitet bland våra deltagare. Fler studier med högre deltagarantal vid liknande komplexa uppgifter behövs.
35

Crack removal and hole filling on composite subdivision meshes / Crack removal and hole filling on composite subdivision meshes

Phan, Anh cang 25 October 2013 (has links)
Construire une surface lisse d'un objet 3D est un problème important dans de nombreuses applications graphiques. En particulier, les méthodes de subdivision permettent de passer facilement d'un maillage discret à une surface continue. Un problème général résultant de la subdivision de deux maillages initialement connectés le long d'un bord est l'apparition de fissures ou de trous entre eux. Ces fissures produisent non seulement des formes indésirables, mais induisent aussi des difficultés pour les traitements ultérieurs. Il faut donc réparer ces défauts de sorte que la surface obtenue soit lisse et puisse être subdivisée ou modifiée. Nous proposons de nouvelles méthodes pour relier deux maillages avec des résolutions différentes en utilisant une transformée en ondelettes B-splines et une approximation locale ou une interpolation locale à l'aide de fonctions de base radiales (RBF). Ces procédés génèrent un maillage de connexion où la continuité est contrôlée. La résolution du maillage est ajustable pour respecter le changement de résolution entre les zones grossières et fines. En outre, nous présentons des méthodes pour combler les trous à n-côtés, et le raffinement des maillages grâce à un schéma de subdivision adaptative. Nous avons conçu, implémenté et testé les algorithmes en MatLab pour illustrer nos méthodes et montrer des résultats expérimentaux. Ces algorithmes sont mis en oeuvre sur de nombreux modèles d'objets 3D avec des formes complexes. En outre, nous avons fourni des approches différentes pour chaque problème. Ainsi, les résultats des différentes approches sont comparés et évalués afin d'exploiter les avantages et les inconvénients de ces approches. / Constructing a smooth surface of a 3D object is an important problem in many graphical applications. In particular, subdivision methods permit to pass easily from a discrete mesh to a continuous surface. A generic problem arising from subdividing two meshes initially connected along a common boundary is the occurrence of cracks or holes between them. These cracks not only produce undesired shapes, but also bring serious trouble for further mesh processing. They must be removed or filled so that the produced surface is smooth and can be further subdivided or edited. In order to remove cracks, we propose new methods for joining two meshes with different resolutions using a Lifted B-spline wavelet transform and a local approximation or radial basis function (RBF) local interpolation. These methods generate a connecting mesh where continuity is controlled from one boundary to the other and the connecting mesh can change gradually in resolution between coarse and fine areas. Additionally, we introduce methods for filling n-sided holes, and refining meshes with an adaptive subdivision scheme. We have designed, implemented, and tested the algorithms in MatLab to illustrate our proposed methods and show experimental results. These algorithms are implemented on many 3D object models with complex shapes. Additionally, we have provided some different approaches for each problem. Thus, results from the different approaches are compared and evaluated to exploit the advantages and disadvantages of these approaches.
36

Ferramentas de Aproximação em Espaços Compactos 2-Homogêneos / Approximation Tools on Compact Two-Point Homogeneous Spaces

Faria, Angelina Carrijo de Oliveira Ganancin 09 August 2019 (has links)
Neste trabalho apresentamos duas caracterizações para o K-funcional do tipo Peetre sobre os espaços compactos 2-homogêneos. Provamos a equivalência no sentido assintótico entre o módulo de suavidade de ordem fracionária e o K-funcional do tipo Peetre, e a equivalência deste último com o raio de aproximação de um operator multiplicativo definido para este propósito. Como consequência obtivemos a desigualdade de Marchaud, neste contexto. Estes resultados generalizam os equivalentes, e bem conhecidos, sobre o contexto esférico. As caracterizações foram aplicadas para mostrar que uma condição abstrata de Hölder, ou de diferenciabilidade de ordem finita, sobre núcleos que geram operadores integrais positivos, implica a obtenção de uma taxa de decrescimento polinomial para suas sequências de autovalores. / We prove two characterization for the Peetre type K-functional on M, a compact two-point homogeneous space. One in terms the rate of approximation of a family of multipliers operator defined to this purpose, and another in terms of the fractional moduli of smoothness. As a direct consequence of those we obtained the Marchaud inequality on this framework. These extend the well known results on the spherical setting. The characterizations are employed to show that an abstract Hölder condition or finite order of differentiability condition imposed on kernels generating certain operators implies a sharp decay rates for their eigenvalues sequences.
37

Renormamiento en espacios de Banach

Guirao Sánchez, Antonio José 18 October 2007 (has links)
La Tesis está compuesta por un capítulo introductorio y cuatro capítulosque pasamos a describir.El Capítulo 2 contiene un análisis de las funciones que son posiblementemódulo de convexidad (m.c.) para un espacio de Banach uniformementeconvexo (UC). Se muestra que las funciones m.c. están caracterizadas,salvo equivalencia, por ciertas propiedades clásicas de éstas.En el Capítulo 3, se estudia la noción de m.c. de una función convexadefinida en un espacio de Banach. Éste es el primer trabajo con resultadosgenerales y completos en espacios de Banach. Se muestra que un espacio essuperreflexivo sii admite una función (UC) definida en todo el espacio.En el Capítulo 4 se resuelve un problema establecido por Godefroy yZizler; un espacio de Banach superreflexivo con base de Schauder admiteuna norma (UC) que hace monótona a la base. Se obtienen mejoras deestimaciones de James y Gurari.En el Capítulo 5 el autor estudia la noción del módulo de cuadratura. Éstepermite reconocer la (UC) y la suavidad uniforme. El autor define laversión local, y prueba varias caracterizaciones del comportamientopuntual de la norma. / The thesis consists of one introductory chapter and four chapterscontaining original mathematical results. Let us pass to a briefdescription of the main results.Chapter 2 contains an analysis of the possible modulus of rotundityfunctions (m.r.f) for a given uniformly rotund (UC) Banach space. It isshown that m.r.f. are characterized, up to equivalence, by certainclassical properties of them.In Chapter 3, the notion of m.r. for a convex function defined on a Banachspace is studied. This seems to be the first instance of rather completegeneral results on Banach spaces. It is shown that a Banach space issuperreflexive iff it admits a (UC) function defined on the whole space.In Chapter 4 a problem asked by Godefroy and Zizler is solved; asuperreflexive Banach space with Schauder basis can be renormed by (UC)norm which makes the given basis monotone. An improvement of a result ofGurarii is an immediate corollary.In Chapter 5 the author studies the notion of modulus of squareness. Itallows to recognize (UC) and uniform smoothness. The author succeeds todefine the local version, and proves various characterizations ofpointwise behaviour of the norm.
38

Régression bayésienne sous contraintes de régularité et de forme. / Bayesian regression under shape and smoothness restriction.

Khadraoui, Khader 08 December 2011 (has links)
Nous étudions la régression bayésienne sous contraintes de régularité et de forme. Pour cela,on considère une base de B-spline pour obtenir une courbe lisse et nous démontrons que la forme d'une spline engendrée par une base de B-spline est contrôlée par un ensemble de points de contrôle qui ne sont pas situés sur la courbe de la spline. On propose différents types de contraintes de forme (monotonie, unimodalité, convexité, etc). Ces contraintes sont prises en compte grâce à la loi a priori. L'inférence bayésienne a permis de dériver la distribution posteriori sous forme explicite à une constante près. En utilisant un algorithme hybride de type Metropolis-Hastings avec une étape de Gibbs, on propose des simulations suivant la distribution a posteriori tronquée. Nous estimons la fonction de régression par le mode a posteriori. Un algorithme de type recuit simulé a permis de calculer le mode a posteriori. La convergence des algorithmes de simulations et du calcul de l'estimateur est prouvée. En particulier, quand les noeuds des B-splines sont variables, l'analyse bayésienne de la régression sous contrainte devient complexe. On propose des schémas de simulations originaux permettant de générer suivant la loi a posteriori lorsque la densité tronquée des coefficients de régression prend des dimensions variables. / We investigate the Bayesian regression under shape and smoothness constraints. We first elicita Bayesian method for regression under shape restrictions and smoothness conditions. Theregression function is built from B-spline basis that controls its regularity. Then we show thatits shape can be controlled simply from its coefficients in the B-spline basis. This is achievedthrough the control polygon whose definition and some properties are given in this article.The regression function is estimated by the posterior mode. This mode is calculated by asimulated annealing algorithm which allows to take into account the constraints of form inthe proposal distribution. A credible interval is obtained from simulations using Metropolis-Hastings algorithm with the same proposal distribution as the simulated annealing algorithm.The convergence of algorithms for simulations and calculation of the estimator is proved. Inparticular, in the case of Bayesian regression under constraints and with free knots, Bayesiananalysis becomes complex. we propose original simulation schemes which allows to simulatefrom the truncated posterior distribution with free dimension.
39

Inverse Problems of Deconvolution Applied in the Fields of Geosciences and Planetology / Problèmes inverses de déconvolution appliqués aux Géosciences et à la Planétologie

Meresescu, Alina-Georgiana 25 September 2018 (has links)
Le domaine des problèmes inverses est une discipline qui se trouve à la frontière des mathématiques appliquées et de la physique et qui réunit les différentes solutions pour résoudre les problèmes d'optimisation mathématique. Dans le cas de la déconvolution 1D, ce domaine apporte un formalisme pour proposer des solutions avec deux grands types d'approche: les problèmes inverses avec régularisation et les problèmes inverses bayésiens. Sous l'effet du déluge de données, les géosciences et la planétologie nécessitent des algorithmes de plus en plus plus complexe pour obtenir des informations pertinentes. Dans le cadre de cette thèse, nous proposons d'apporter des connaissances dans trois problèmes de déconvolution 1D sous contrainte avec régularisation dans le domaine de l'hydrologie, la sismologie et de la spectroscopie. Pour chaque problème nous posons le modèle direct, le modèle inverse, et nous proposons un algorithme spécifique pour atteindre la solution. Les algorithmes sont définis ainsi que les différentes stratégies pour déterminer les hyper-paramètres. Aussi, des tests sur des données synthétiques et sur des données réelles sont exposés et discuté du point de vue de l'optimisation mathématique et du point de vue du domaine de l'application choisi. Finalement, les algorithmes proposés ont l'objectif de mettre à portée de main l'utilisation des méthodes des problèmes inverses pour la communauté des Géosciences. / The inverse problem field is a domain at the border between applied mathematics and physics that encompasses the solutions for solving mathematical optimization problems. In the case of 1D deconvolution, the discipline provides a formalism to designing solutions in the frames of its two main approaches: regularization based inverse problems and bayesian based inverse problems. Under the data deluge, geosciences and planetary sciences require more and more complex algorithms for obtaining pertinent information. In this thesis, we solve three 1D deconvolution problems under constraints with regularization based inverse problem methodology: in hydrology, in seismology and in spectroscopy. For every of the three problems, we pose the direct problem, the inverse problem, and we propose a specific algorithm to reach the solution. Algorithms are defined but also the different strategies to determine the hyper-parameters. Furthermore, tests on synthetic data and on real data are presented and commented from the point of view of the inverse problem formulation and that of the application field. Finally, the proposed algorithms aim at making approachable the use of inverse problem methodology for the Geoscience community.
40

Lietuvos svarbiausių magistralinių kelių eksploatacinių savybių kitimo analizė / Analysis of the Change in Service Properties of the Most Important Main Roads in Lithuania

Stankevičiūtė, Diana 22 June 2010 (has links)
Prieš rengiant kelių investicinius projektus surenkami ir detaliai analizuojami esami kelių eksploatacinių rodiklių duomenys ir jų reglamentuotų norminių reikšmių atitiktis. Baigiamajame darbe išanalizuoti automobilių kelių asfaltbetonio dangos būklės, patikimumo bei šių rodiklių gavimo ir apdorojimo metodai. Pateikiamas automobilių kelių asfaltbetonio dangos reikiamų eksploatacinių rodiklių teorinis pagrindimas, reglamentuotos norminės reikšmės bei eksploatacinių rodiklių gerinimo svarba. Naudojantis tyrimų, atliktų Lietuvos svarbiausiuose magistraliniuose keliuose A1 Vilnius – Kaunas - Klaipėda ir A5 Kaunas – Marijampolė - Suvalkai, duomenimis, atlikta pagrindinių eksploatacinių rodiklių - dangos lygumo, rato su danga sukibimo koeficiento, dangos suirimo masto rodiklio, konstrukcijos deformacijos modulio bei provėžų gylio analizė ir šių rodiklių kitimas laiko atžvilgiu. Nustatyta dangos būklę apibūdinančių rodiklių sietis. Analizės pagrindu pateikti rekomenduojami leistinieji dangos lygumo rodikliai. Pateiktos išvados ir rekomendacijos. Baigiamojo darbo aprašomojo skyriaus apimtis – 89 psl., 17 lentelių, 90 paveikslų, 44 bibliografiniai šaltiniai. / Before the preparation of highway investment projects, the available data of highway maintenance indices are collected and analysed and their conformity with the standard values is established. The thesis deals with the analysis of reliability of the condition of highway asphalt concrete pavement and the indices collection and procession methods. The thesis includes the theoretical grounding of the necessary maintenance indices of the highway asphalt concrete pavement, standard values and the importance of improvement of the maintenance indices. Using the data of the testing performed in the main Lithuanian highways A1 Vilnius – Kaunas - Klaipėda and A5 Kaunas – Marijampolė - Suvalkai, the analysis of the basic maintenance indices, i.e. pavement smoothness, wheel adherence coefficient, pavement breakup degree index, construction deformation module and furrow depth, and the change of such indices in the terms of time has been carried out. The link between the indices characterising the condition of the pavement has been determined. Basing on the analysis, the recommended permitted pavement smoothness indices are presented. The conclusions and recommendations of the thesis are introduced. Theses consist of: 89 p. text without appendixes, 90 pictures, 17 tables, 44 bibliographical entries.

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