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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

Relationships between Model Theory and Valuations of Fields / Model Theory and Valuations

Sinclair, Peter 11 1900 (has links)
This thesis explores some of the relationships between model theoretic and algebraic properties of fields, focusing on valuations of fields. We first show that the dp-rank of henselian valued fields admitting relative quantifier elimination is equal to the sum of the dp-ranks of the value group and of the residue field. Moreover, we give a characterization of henselianity of valued fields of finite dp-rank in terms of the dp-rank of definable sets. We also obtain partial results generalizing the work of Johnson in classifying fields of finite dp-rank. Finally, we consider fields with the property that the algebraic closure is an immediate extension with respect to every valuation. We show that under certain conditions these fields are dense in their algebraic closure with respect to every valuation and provide an example that demonstrates that this property does not hold in general. / Thesis / Doctor of Philosophy (PhD)
32

Lietuvių gyvenimas ir veikla Kempteno DP stovykloje 1945 – 1949 m / Lithuanian’s life and activities in Kempten DP camp in 1945-1949

Žūsinas, Gediminas 17 June 2011 (has links)
Kempteno karo pabėgėlių stovykla pasirinkta neatsitiktinai, stovykloje telkėsi nemažas skaičius lietuvių. Analizuojant DP laikotarpį buvo pasigesta būtent tyrinėjimų skirtų konkrečiai stovyklai, kurioje gyveno lietuvių pabėgėliai. Istorikų darbuose, pristatant visą stovyklinio laikotarpio gyvenimą, kol kas apsiribojama tik bendrais bruožais, plačiau nesigilinant į vienos stovyklos gyvenimą. Lietuviai yra viena iš tų tautų, kuri turi savo emigracijos istoriją. XIX a. pabaigoje – XX a. pradžioje lietuviai tapo emigrantų tauta. Dar prieš Pirmąjį pasaulinį karą tūkstančiai Lietuvos šeimų apleido savo šalį ieškodami geresnio ir sotesnio gyvenimo svetur. Daugiausiai jų patraukė į naujų galimybių ir svajonių šalį – Ameriką. Baigiantis Antrajam pasauliniam karui ir artinantis antrajai sovietų okupacijai dešimtys tūkstančių Lietuvos gyventojų kartu su vokiečių kariuomene traukėsi į Vakarus. Tai buvo politinė emigracija. Į Vakarus traukėsi daug išsilavinusių žmonių, tautos žiedas: žymūs politikai, menininkai, mokslininkai, tie kurie nepriklausomoje Lietuvoje užėmė aukštas pareigas. Pasibaigus karui daugiausiai lietuvių susibūrė Vokietijos DP stovyklose, kur juos globojo tarptautinės UNRRA, vėliau IRO organizacijos, kurios rūpinosi karo pabėgėlių šelpimu, apgyvendinimu ir tolimesne emigracija. Didžioji dalis lietuvių pabėgėlių emigravo į JAV (apie 30 tūkst.), o likusieji į Australiją, Kanadą ir Pietų Amerikos valstybes. Nors pirmaisiais pokario metais daug kas tikėjo greitu Lietuvos... [toliau žr. visą tekstą] / The camp of the war refugees of Kempten has been chosen not accidentally as quite a big number of Lithuanians was gathered in that camp. When analyzing the period of DP, there was a lack of studies particularly about this camp where Lithuanian refugees lived. When presenting the life of the whole camp period, historians’ works did not include the description the life of Kempten camp in more details. It was limited only to general descriptions. The Lithuanian nation is one of the those who have their history of emigration. Lithuanians became a nation of emigration at the end of 19th century and the beginning of the 20th century. Even before World War I thousands of families of Lithuania left their country when looking for a better life abroad. Most of them headed for America, the country of new possibilities and dreams. With the end of World War II and the approach of the second soviet occupation thousands of inhabitants of Lithuania retreated to the West together with the German troops. It was a political emigration. A lot of educated people retreated to the West: famous politicians, artists, scientists, also the ones who held high positions. After the war most of Lithuanians gathered in DP camps in Germany where they were fostered by international organization UNRRA and later by IRO which supported war refugees, provided them with accommodation and took care of their further emigration. Most of Lithuanian refugees emigrated to USA (appr. 30 thous.) and the rest part left for... [to full text]
33

Human herpes virus-6 induced changes in the expression and activity of the E2F family transcription factors in human cells

Khan, Mehtab A. January 2005 (has links)
Mémoire numérisé par la Direction des bibliothèques de l'Université de Montréal.
34

Effets des prostaglandines I₂ et E₂ sur la réactivité des muscles lisses pulmonaires humains : implications pour le traitement de l’hypertension pulmonaire / Effects of prostaglandin I₂ and E₂ on the reactivity of human pulmonary smooth muscle : implications for the treatment of pulmonary hypertension

Benyahia, Chabha 09 July 2015 (has links)
L’hypertension pulmonaire (HTP) est caractérisée par une augmentation progressive des résistances vasculaires pulmonaires, une élévation de la pression artérielle pulmonaire moyenne (≥25 mm Hg) et un déséquilibre entre la production des médiateurs endothéliaux vasoconstricteurs et vasodilatateurs conduisant ainsi à une insuffisance cardiaque droite. Les mimétiques de la prostaglandines (PG)I2 (prostacycline), tels que l'iloprost et le tréprostinil, constituent un des traitements majeurs de l’HTP. L’efficacité des traitements utilisés dans l’http étant évaluée principalement sur l’amélioration de la tolérance à l’effort et la diminution de la dyspnée, il est important d’analyser leurs effets vasodilatateurs artériels mais aussi veineux pulmonaires ainsi que les effets bronchodilatateurs. Ces travaux décrivent les effets, in vitro, de la PGI2, de la PGE2 et de leurs mimétiques sur la réactivité des préparations vasculaires (artères et veines) pulmonaires et bronchiques humaines provenant de patients contrôles ou ayant une HTP. Nous avons caractérisé les différents récepteurs aux prostanoïdes impliqués dans ces réponses. Nos travaux suggèrent que les mimétiques de la PGI2, le treprostinil et l’iloprost, utilisés en clinique, sont d’une part de puissants vasodilatateurs à la fois des artères et des veines pulmonaires et d’autre part, de puissants bronchodilatateurs. Certains mimétiques de la PGI2 (iloprost et tréprostinil) ont des effets vasodilatateurs proportionnels sur les artères et veines pulmonaires. D’autres mimétiques de la PGI2 (béraprost) entraînent une vasodilatation artérielle pulmonaire plus importante que la vasodilatation veineuse. Ceci pourrait entraîner un œdème pulmonaire ou un moindre effet bénéfique sur la correction de la dyspnée. Nous avons mis en évidence une diminution de l’expression des récepteurs IP et DP dans les préparations vasculaires des patients ayant une HTP versus les patients contrôles. Cette diminution est associée avec la réduction de la relaxation des veines pulmonaires induite par le tréprostinil. De même, nous avons montré une diminution de l’expression du récepteur EP4 dans les voies respiratoires des patients ayant une HTP de type 3 ; elle est associée à la réduction de la bronchodilatation induite par les agonistes du récepteur EP4. La correction de cette diminution pourrait être une nouvelle perspective thérapeutique chez ces patients. Nos résultats permettent une meilleure compréhension des effets bénéfiques ou délétères, pharmacologiques et thérapeutiques des mimétiques de la PGI2 déjà utilisées en clinique dans le traitement de l’HTP. A travers la voie PGE2/EP4, nos travaux ouvrent de nouvelles perspectives physiopathologiques et potentiellement thérapeutiques. / Pulmonary hypertension (PH) is characterized by a progressive increase of pulmonary vascular resistance, an increase of mean pulmonary arterial pressure (≥25 mm Hg) and an imbalance between the production of endothelial vasoconstrictor and vasodilator mediators leading to right heart failure. Prostaglandin (PG)I2 (prostacyclin) mimetics, such as iloprost and treprostinil, are major therapeutic tools for this pathology. The efficacy of the treatments used in PH is evaluated primarily on the improvement of exercise tolerance and reduction of dyspnea. For this reason it is important to analyze not only the arterial but also the venous vasodilator effects as well as bronchodilator effects. This thesis describes the in vitro effects of PGI2, PGE2 and their mimetics on the reactivity of human pulmonary vascular (ateries and veins) and bronchial preparations derived from patients with or without PH. We also characterized different prostanoid receptors involved in these responses. Our results suggest that PGI2 mimetics, treprostinil and iloprost, used clinically, are potent vasodilators for both pulmonary arteries and veins and also potent bronchodilators. Some PGI2 mimetics (treprostinil and iloprost) have proportional vasodilatory effects on the pulmonary arteries and veins. Other PGI2 mimetics, such as beraprost, cause greater pulmonary arterial vasodilation than venous vasodilation. This may cause pulmonary edema or less beneficial effects on dyspnea correction. We showed decreased expression of IP and DP1 receptors in vascular preparations of patients with PH versus control patients. This decrease is associated with reduced relaxation response of pulmonary veins induced by treprostinil. Similarly, we demonstrated a reduction in EP4 receptor expression in bronchial preparations of patients with group 3 PH. This down regulation was associated with reduced bronchodilation induced by EP4 agonists. The correction of this down-regulation may be a new therapeutic perspective in these patients. Our results enhance our understanding of the beneficial or deleterious, pharmacological and therapeutic effects of PGI2 mimetics already used clinically in the treatment of PH. Through PGE2/EP4 pathway our work opens new physiopathological and potential therapeutic perspectives.
35

Simulador de redes Profibus / Profibus network simulator

Torres, Renato da Veiga 19 September 2013 (has links)
Este trabalho propõe o desenvolvimento de um simulador de redes Profibus DP que reproduz o comportamento de uma rede real. A simulação de redes em condições de falha permite aos usuários experimental situações que podem ocorrer em instalações reais, facilitando o treinamento de manutenção e antecipando ações corretivas. O simulador permite o treinamento de usuários que utilizam ferramentas de diagnóstico. Auxilia no estudo do protocolo Profibus DP e também contribui com o desenvolvimento da ferramenta Profidoctor que é um sistema especialista com o objetivo de fazer a análise de problemas de rede. / This work aims development of Profibus DP network simulator that reproduces real network behavior. The network simulation under fault conditions allows experiment situations that may occur in real network installations, helping in maintenance training and corrective actions. This simulator tool helps in diagnostic tool users training, Profibus DP protocol learning and also assists development of new tool Profidoctor: an expert system that will report complete analysis of network problems.
36

Análise de desempenho de redes de comunicação industrial em acionamentos de motores elétricos trifásicos / Performance analysis of industrial communication networks in electrical motors drives

Dias, André Luís 09 December 2014 (has links)
Este trabalho propõe analisar o desempenho de redes de comunicação industrial em aplicações de acionamentos de motores elétricos trifásicos. Compara-se o desempenho da tecnologia Profibus DP em relação à Profinet. O desempenho é verificado a partir de especificações técnicas de ambos protocolos e experimentos práticos para coleta de dados e análise dos seguintes indicadores de desempenho: tempo de ciclo, jitter e ocupação de largura de banda. Adicionalmente, é verificado o desempenho de uma aplicação de controle de posição, utilizando estes protocolos na malha de controle, através do tempo de acomodação do sistema. Conclusões mostram que a rede Profibus DPV0 é a mais rápida quando possui menos dispositivos, porém o Profinet RT consegue manter baixos valores de tempo de ciclo mesmo com grande quantidade de dispositivos e possui maior determinismo na topologia em barramento. No que diz respeito ao controle de posição estudado, as tecnologias apresentam desempenho similar para tempo de acomodação do sistema, porém o Profinet IRT foi o mais determinístico. / This work proposes a performance analysis of industrial communication networks in applications of electric AC motor drives. It compares the performance of Profibus DP technology in relation to Profinet. Performance is verified from technical specifications of both protocols and practical experiments for data collection and analysis of the following performance indicators: cycle time, jitter and bandwidth occupation. Additionally, the performance of a motion control application is verified, by using these protocols in the loop control, through the settling time of the system. Conclusions show that Profibus DPV0 is faster when there is less devices in the network, but Profinet RT manages to maintain low values of cycle time even with large number of devices and has higher determinism when installed in line topology. Regarding the motion control application studied, the technologies have similar settling time for the system performance, but the Profinet IRT was more deterministic.
37

Análise de desempenho de redes de comunicação industrial em acionamentos de motores elétricos trifásicos / Performance analysis of industrial communication networks in electrical motors drives

André Luís Dias 09 December 2014 (has links)
Este trabalho propõe analisar o desempenho de redes de comunicação industrial em aplicações de acionamentos de motores elétricos trifásicos. Compara-se o desempenho da tecnologia Profibus DP em relação à Profinet. O desempenho é verificado a partir de especificações técnicas de ambos protocolos e experimentos práticos para coleta de dados e análise dos seguintes indicadores de desempenho: tempo de ciclo, jitter e ocupação de largura de banda. Adicionalmente, é verificado o desempenho de uma aplicação de controle de posição, utilizando estes protocolos na malha de controle, através do tempo de acomodação do sistema. Conclusões mostram que a rede Profibus DPV0 é a mais rápida quando possui menos dispositivos, porém o Profinet RT consegue manter baixos valores de tempo de ciclo mesmo com grande quantidade de dispositivos e possui maior determinismo na topologia em barramento. No que diz respeito ao controle de posição estudado, as tecnologias apresentam desempenho similar para tempo de acomodação do sistema, porém o Profinet IRT foi o mais determinístico. / This work proposes a performance analysis of industrial communication networks in applications of electric AC motor drives. It compares the performance of Profibus DP technology in relation to Profinet. Performance is verified from technical specifications of both protocols and practical experiments for data collection and analysis of the following performance indicators: cycle time, jitter and bandwidth occupation. Additionally, the performance of a motion control application is verified, by using these protocols in the loop control, through the settling time of the system. Conclusions show that Profibus DPV0 is faster when there is less devices in the network, but Profinet RT manages to maintain low values of cycle time even with large number of devices and has higher determinism when installed in line topology. Regarding the motion control application studied, the technologies have similar settling time for the system performance, but the Profinet IRT was more deterministic.
38

Software concepts and algorithms for an efficient and scalable parallel finite element method

Witkowski, Thomas 08 May 2014 (has links) (PDF)
Software packages for the numerical solution of partial differential equations (PDEs) using the finite element method are important in different fields of research. The basic data structures and algorithms change in time, as the user\'s requirements are growing and the software must efficiently use the newest highly parallel computing systems. This is the central point of this work. To make efficiently use of parallel computing systems with growing number of independent basic computing units, i.e.~CPUs, we have to combine data structures and algorithms from different areas of mathematics and computer science. Two crucial parts are a distributed mesh and parallel solver for linear systems of equations. For both there exists multiple independent approaches. In this work we argue that it is necessary to combine both of them to allow for an efficient and scalable implementation of the finite element method. First, we present concepts, data structures and algorithms for distributed meshes, which allow for local refinement. The central point of our presentation is to provide arbitrary geometrical information of the mesh and its distribution to the linear solver. A large part of the overall computing time of the finite element method is spend by the linear solver. Thus, its parallelization is of major importance. Based on the presented concept for distributed meshes, we preset several different linear solver methods. Hereby we concentrate on general purpose linear solver, which makes only little assumptions about the systems to be solver. For this, a new FETI-DP (Finite Element Tearing and Interconnect - Dual Primal) method is proposed. Those the standard FETI-DP method is quasi optimal from a mathematical point of view, its not possible to implement it efficiently for a large number of processors (> 10,000). The main reason is a relatively small but globally distributed coarse mesh problem. To circumvent this problem, we propose a new multilevel FETI-DP method which hierarchically decompose the coarse grid problem. This leads to a more local communication pattern for solver the coarse grid problem and makes it possible to scale for a large number of processors. Besides the parallelization of the finite element method, we discuss an approach to speed up serial computations of existing finite element packages. In many computations the PDE to be solved consists of more than one variable. This is especially the case in multi-physics modeling. Observation show that in many of these computation the solution structure of the variables is different. But in the standard finite element method, only one mesh is used for the discretization of all variables. We present a multi-mesh finite element method, which allows to discretize a system of PDEs with two independently refined meshes. / Softwarepakete zur numerischen Lösung partieller Differentialgleichungen mit Hilfe der Finiten-Element-Methode sind in vielen Forschungsbereichen ein wichtiges Werkzeug. Die dahinter stehenden Datenstrukturen und Algorithmen unterliegen einer ständigen Neuentwicklung um den immer weiter steigenden Anforderungen der Nutzergemeinde gerecht zu werden und um neue, hochgradig parallel Rechnerarchitekturen effizient nutzen zu können. Dies ist auch der Kernpunkt dieser Arbeit. Um parallel Rechnerarchitekturen mit einer immer höher werdenden Anzahl an von einander unabhängigen Recheneinheiten, z.B.~Prozessoren, effizient Nutzen zu können, müssen Datenstrukturen und Algorithmen aus verschiedenen Teilgebieten der Mathematik und Informatik entwickelt und miteinander kombiniert werden. Im Kern sind dies zwei Bereiche: verteilte Gitter und parallele Löser für lineare Gleichungssysteme. Für jedes der beiden Teilgebiete existieren unabhängig voneinander zahlreiche Ansätze. In dieser Arbeit wird argumentiert, dass für hochskalierbare Anwendungen der Finiten-Elemente-Methode nur eine Kombination beider Teilgebiete und die Verknüpfung der darunter liegenden Datenstrukturen eine effiziente und skalierbare Implementierung ermöglicht. Zuerst stellen wir Konzepte vor, die parallele verteile Gitter mit entsprechenden Adaptionstrategien ermöglichen. Zentraler Punkt ist hier die Informationsaufbereitung für beliebige Löser linearer Gleichungssysteme. Beim Lösen partieller Differentialgleichung mit der Finiten Elemente Methode wird ein großer Teil der Rechenzeit für das Lösen der dabei anfallenden linearen Gleichungssysteme aufgebracht. Daher ist deren Parallelisierung von zentraler Bedeutung. Basierend auf dem vorgestelltem Konzept für verteilten Gitter, welches beliebige geometrische Informationen für die linearen Löser aufbereiten kann, präsentieren wir mehrere unterschiedliche Lösermethoden. Besonders Gewicht wird dabei auf allgemeine Löser gelegt, die möglichst wenig Annahmen über das zu lösende System machen. Hierfür wird die FETI-DP (Finite Element Tearing and Interconnect - Dual Primal) Methode weiterentwickelt. Obwohl die FETI-DP Methode vom mathematischen Standpunkt her als quasi-optimal bezüglich der parallelen Skalierbarkeit gilt, kann sie für große Anzahl an Prozessoren (> 10.000) nicht mehr effizient implementiert werden. Dies liegt hauptsächlich an einem verhältnismäßig kleinem aber global verteilten Grobgitterproblem. Wir stellen eine Multilevel FETI-DP Methode vor, die dieses Problem durch eine hierarchische Komposition des Grobgitterproblems löst. Dadurch wird die Kommunikation entlang des Grobgitterproblems lokalisiert und die Skalierbarkeit der FETI-DP Methode auch für große Anzahl an Prozessoren sichergestellt. Neben der Parallelisierung der Finiten-Elemente-Methode beschäftigen wir uns in dieser Arbeit mit der Ausnutzung von bestimmten Voraussetzung um auch die sequentielle Effizienz bestehender Implementierung der Finiten-Elemente-Methode zu steigern. In vielen Fällen müssen partielle Differentialgleichungen mit mehreren Variablen gelöst werden. Sehr häufig ist dabei zu beobachten, insbesondere bei der Modellierung mehrere miteinander gekoppelter physikalischer Phänomene, dass die Lösungsstruktur der unterschiedlichen Variablen entweder schwach oder vollständig voneinander entkoppelt ist. In den meisten Implementierungen wird dabei nur ein Gitter zur Diskretisierung aller Variablen des Systems genutzt. Wir stellen eine Finite-Elemente-Methode vor, bei der zwei unabhängig voneinander verfeinerte Gitter genutzt werden können um ein System partieller Differentialgleichungen zu lösen.
39

Simulador de redes Profibus / Profibus network simulator

Renato da Veiga Torres 19 September 2013 (has links)
Este trabalho propõe o desenvolvimento de um simulador de redes Profibus DP que reproduz o comportamento de uma rede real. A simulação de redes em condições de falha permite aos usuários experimental situações que podem ocorrer em instalações reais, facilitando o treinamento de manutenção e antecipando ações corretivas. O simulador permite o treinamento de usuários que utilizam ferramentas de diagnóstico. Auxilia no estudo do protocolo Profibus DP e também contribui com o desenvolvimento da ferramenta Profidoctor que é um sistema especialista com o objetivo de fazer a análise de problemas de rede. / This work aims development of Profibus DP network simulator that reproduces real network behavior. The network simulation under fault conditions allows experiment situations that may occur in real network installations, helping in maintenance training and corrective actions. This simulator tool helps in diagnostic tool users training, Profibus DP protocol learning and also assists development of new tool Profidoctor: an expert system that will report complete analysis of network problems.
40

A study to investigate the mathematical relationships between the frequency composition of the first heart sound and the force generating capability of the heart

Swick, Julie Burkey January 1987 (has links)
No description available.

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