• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 7
  • 3
  • 2
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • Tagged with
  • 19
  • 19
  • 5
  • 5
  • 4
  • 4
  • 4
  • 3
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 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.
11

Epochenvergleiche von Präzisions-EDM-Messungen zur Untersuchung der Punktstabilität auf einer EDM-Basislinie

Lehmann, Rüdiger, Attrodt, Antje January 2016 (has links)
Auf der von der Hochschule für Technik und Wirtschaft Dresden betriebene EDM-Basislinie im Großen Garten in Dresden werden regelmäßig die Sollstrecken überprüft. Die Ergebnisse deuten auf Punktbewegungen hin. Durch Vergleiche zweier Epochen wird versucht, solche Punktbewegungen statistisch nachzuweisen, sowohl mittels statistischer Hypothesentests, als auch mit einem Informationskriterium. Punktbewegungen von bis zu 0,25 mm/a wurden geschätzt. Über die Ursachen wird noch spekuliert.
12

Bed Deformation and Navigable Channel Characteristics in Braided Stream / 網状流路河川における河床変動と可航流路特性 / # ja-Kana

Tin, Tin Htwe 25 September 2018 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第21353号 / 工博第4512号 / 新制||工||1703(附属図書館) / 京都大学大学院工学研究科社会基盤工学専攻 / (主査)教授 藤田 正治, 教授 中川 一, 准教授 竹林 洋史 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM
13

Methodology based on registration techniques for representing subjects and their deformations acquired from general purpose 3D sensors

Saval-Calvo, Marcelo 29 May 2015 (has links)
In this thesis a methodology for representing 3D subjects and their deformations in adverse situations is studied. The study is focused in providing methods based on registration techniques to improve the data in situations where the sensor is working in the limit of its sensitivity. In order to do this, it is proposed two methods to overcome the problems which can difficult the process in these conditions. First a rigid registration based on model registration is presented, where the model of 3D planar markers is used. This model is estimated using a proposed method which improves its quality by taking into account prior knowledge of the marker. To study the deformations, it is proposed a framework to combine multiple spaces in a non-rigid registration technique. This proposal improves the quality of the alignment with a more robust matching process that makes use of all available input data. Moreover, this framework allows the registration of multiple spaces simultaneously providing a more general technique. Concretely, it is instantiated using colour and location in the matching process for 3D location registration.
14

[pt] IMPLEMENTAÇÃO NUMÉRICA DO MODELO CONSTITUTIVO ELASTOPLÁSTICO DE LADE E KIM PARA ANÁLISE 3D DE ATERROS / [en] NUMERICAL IMPLEMENTATION OF THE ELASTOPLASTIC CONSTITUTIVE MODEL OF LADE AND KIM FOR 3D ANALYSIS OF EMBANKMENTS

JUAN ANDRES HUANG SAM 15 December 2020 (has links)
[pt] Problemas de engenharia geotécnica onde a resistência ao cisalhamento é fator determinante para o projeto são geralmente avaliados com base no critério de ruptura de Mohr-Coulomb; no entanto, modelos constitutivos avançados são necessários para abordar grande parte de problemas geotécnicos onde estimativas de deformação são necessárias. Lade e Kim propuseram um modelo constitutivo elastoplástico avançado para investigar o comportamento tensão vs. deformação de materiais com atrito, sob condição drenada ou não drenada. Nesta dissertação, este modelo foi implementado no programa computacional de diferenças finitas FLAC3D com o objetivo de estudar o comportamento elasto-plástico de aterros. As equações governantes do modelo constitutivo de Lade-Kim são apresentadas e um algoritmo explícito de integração de tensões foi implementado na presente pesquisa. Os resultados numéricos obtidos com o modelo de Lade e Kim foram comparados com aqueles publicados na literatura, envolvendo ensaios triaxiais de laboratório realizados em areia e análises numéricas 2D do comportamento de barragem. Finalmente, após validação da implementação do modelo, análises do comportamento 2D e 3D de aterros foram executadas, verificando a influência destes tipos de análise nos valores calculados, bem como resultados numéricos foram também comparados com aqueles determinados pelo tradicional modelo elasto-plástico de Mohr-Coulomb. / [en] Geotechnical engineering problems, where the design is mainly influenced by the shear strength, can be successfully analyzed considering a traditional constitutive model; however, advanced constitutive models must be used when the estimative of deformation is an important factor to be considered. Lade and Kim proposed the Lade-Kim model in order to model a granular material stress-strain constitutive relation under different combinations of effective stress and drained or undrained conditions. In this dissertation, this model is implemented and validated in the FLAC3D finite volume program, in order to study the elasto-plastic behavior of embankments. The governing equations of the constitutive model of Lade-Kim are presented and, using an appropriate stress integration algorithm, it is implemented in FLAC3D. This procedure is validated by using experimental results of triaxial tests performed on the sand of the Sacramento River and performing two-dimensional deformation analyzes of embankments and comparing the results with the literature. Finally, the Lade-Kim model is used in two-dimensional and three-dimensional deformation analyses of embankments in order to analyze the influence of the three-dimensional condition. On the other hand, the same analyzes were carried out using the Mohr- Coulomb constitutive model in order to compare the results and analyze the efficiency of the Lade-Kim constitutive model. Thus, it is concluded that the Lade-Kim constitutive model was successfully implemented and that it provides accurate results regarding modeling geomechanical behavior under different combinations of effective stresses.
15

Geodinamička analiza pomeranja Zemljine kore regionalnog karaktera / A geodynamical analysis of Earth's crust movements of regional character

Sušić Zoran 08 March 2014 (has links)
<p>Stanje Zemljine kore određeno je istovremenim i suprotstavljenim uticajem<br />endodinamičkih i egzodinamičkih procesa. Povr&scaron;inski slojevi omotača<br />Zemljine kore su u stalnom pokretu pod dejstvom uticaja, kao &scaron;to su<br />promena nivoa podzemnih voda, tektonske pojave, klizi&scaron;ta itd. Značajne<br />deformacije mogu se javiti kao posledica niza regionalnih i lokalnih<br />naponskih stanja, posebno u graničnim zonama litosfernih ploča, gde se<br />akumuliraju naponi i javljaju nelinearne innterseizmičke deformacije. U<br />disertaciji je prikazano istraživanje pomeranja Zemljine kore regionalnog<br />karaktera sa geodetskog aspekta, na osnovu ponovljenih opažanja metodom<br />satelitskog pozicioniranja, čime je dat doprinos multidisciplinarnom<br />razumevanju stanja Zemljine kore.</p> / <p>The state of the Earth&rsquo;s crust is determined by the simultaneous and opposed<br />influence of the endodynamic and exodynamic processes. The surface layers of<br />the Earth&rsquo;s crust envelope are in the state of permanent moving due to divers<br />influences, such as the level variation of underground waters, tectonic<br />phenomena, landslides, etc. Significant deformations can arise as a consequence<br />of a number of regional and local strain states, especially in the boundary zones<br />of lithosphere plates where strains are accumulated and non-linear interseismic<br />deformations appear. The subject of the thesis is a study of movements of the<br />Earth&rsquo;s crust of regional character from the aspect of geodesy, on the basis of<br />repeated observations by applying the satellite positioning method. In this way a<br />contribution is given to a multidisciplinary concept of the state of the Earth&rsquo;s crust.</p>
16

Výpočtové modelování rámu obráběcího stroje / Computational modeling of machine tool frame

Hermanský, Dominik January 2014 (has links)
The subject of my master’s thesis is creating a computational model of a vertical turning centre frame. The frame is influenced by the heat generated in a motion system. The computational model was created to evaluate a temperature distribution in machine frame structure and thermal deformations caused by temperature gradients.
17

Automatizace geodetických měření a jejich datová analýza / Automation of Geodetic Measurements and Their Data Analysis

Vojkůvka, Michal January 2018 (has links)
The present thesis deals with the process of automation of geodetic measurements using electronic geodetic instruments, e.g. electronic levels, electronic total stations, as well as other measuring instruments and devices generally used for geodetic measurements, including meteorological sensors. The goal is to design and create a platform for automated measurement system with integrated data collection, their storage and analysis with the help of remote internet access and allowing to export data in various formats.
18

Recalage non rigide d'images par approches variationnelles statistiques. Application à l'analyse et à la modélisation de la fonction myocardique en IRM

Petitjean, Caroline 01 September 2003 (has links) (PDF)
L'analyse quantitative de la fonction contractile myocardique constitue un enjeu majeur pour le dépistage, le traitement et le suivi des maladies cardio-vasculaires, première cause de mortalité dans les pays développés. Dans ce contexte, l'Imagerie par Résonance Magnétique (IRM) s'impose comme une modalité privilégiée pour l'exploration dynamique du coeur, renseignant, d'une part, sur l'évolution des parois (ciné IRM), et permettant, d'autre part, d'accéder à des informations cinématiques au sein du myocarde (IRM de marquage). L'exploitation quantitative de ces données est néanmoins actuellement limitée par la quasi-absence de méthodologies fiables, robustes et reproductibles d'estimation de mouvement non rigide à partir de séquences d'images acquises dans cette modalité.<br /><br />Cette thèse se propose de démontrer que les techniques de recalage non rigide statistique constituent un cadre approprié pour l'estimation des déformations myocardiques en IRM, leur quantification à des fins diagnostiques, et leur modélisation en vue d'établir une référence numérique de normalité. Ses contributions concernent :<br /><br /> 1. l'élaboration d'une méthode robuste non supervisée d'estimation des déplacements myocardiques à partir de séquences d'IRM de marquage. Elle permet l'obtention de mesures de mouvement fiables en tout point du myocarde, à tout instant du cycle cardiaque et sous incidence de coupe arbitraire.<br /><br /> 2. le développement d'un outil de quantification dynamique des déformations à l'échelle du pixel et du segment myocardique, intégrant un étape de segmentation automatique du coeur par recalage d'images ciné IRM acquises conjointement aux données de marquage. Pour le coeur sain, la comparaison des mesures obtenues à des valeurs de référence issues d'une synthèse approfondie de la littérature médicale démontre une excellente corrélation. Pour des coeurs pathologiques, les expériences menées ont montré la pertinence d'une analyse quantitative multiparamétrique pour localiser et caractériser les zones atteintes.<br /><br /> 3. la construction d'un modèle statistique (atlas) de contraction d'un coeur sain. Cet atlas fournit des modèles quantitatifs de référence locaux et segmentaires pour les paramètres de déformation. Son intégration, en tant que modèle de mouvement, au processus de recalage des données d'IRM de marquage conduit en outre à une description très compacte des déplacements myocardiques sans perte de précision notable.
19

Analýza kostry synchronního generátoru / The analysis of frame synchronous generator

Marada, Ondřej January 2011 (has links)
The thesis is focused on the examination of the utility of a synchronous generator of a small hydroelectric power station in the case of a change of working position of the machine. The utility will be measured on the basis of the examination of deformations and state of stress of the frame of the generator for the present running (with vertical axis of rotation of the generator) and subsequently for modified running (with horizontal axis of rotation). This will be accomplished partly on the static shell model by finite element method and consequently on the simplified dynamic model.

Page generated in 0.1433 seconds