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Frühwirth, Rudolf, Korbinian Eckstein, and Sylvia Frühwirth-Schnatter. "Vertex finding by sparse model-based clustering." IOP Publishing, 2016. http://epub.wu.ac.at/6173/1/jop.pdf.
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The application of sparse model-based clustering to the problem of primary vertex finding is discussed. The observed z-positions of the charged primary tracks in a bunch crossing are modeled by a Gaussian mixture. The mixture parameters are estimated via Markov Chain Monte Carlo (MCMC). Sparsity is achieved by an appropriate prior on the mixture weights. The results are shown and compared to clustering by the expectation-maximization (EM) algorithm.
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Mosaffa, Payman. "Hybrid cell-centred/vertex model for multicellular systems." Doctoral thesis, Universitat Politècnica de Catalunya, 2017. http://hdl.handle.net/10803/461678.
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This thesis presents a hybrid vertex/cell-centred approach to mechanically simulate planar cellular monolayers undergoing cell reorganisation. Cell centres are represented by a triangular nodal network, while the cell boundaries are formed by an associated vertex network. The two networks are coupled through a kinematic constraint which we allow to relax progressively. Cell-cell connectivity changes due to cell reorganisation or remodelling events, are accentuated. These situations are handled by using a variable resting length and applying an Equilibrium-Preserving Mapping (EPM) on the new connectivity, which computes a new set of resting lengths that preserve nodal and vertex equilibrium. As a by-product, the proposed technique enables to recover fully vertex or fully cell-centred models in a seamless manner by modifying a numerical parameter of the model. The properties of the model are illustrated by simulating monolayers subjected to imposed extension and during a wound healing process. The evolution of forces and the EPM are analysed during the remodelling events.Esta tesis presenta un modelo híbrido para la simulación mecánica de monocapas celulares. Este modelo combina métodos de vértices y centrados en la célula, y está orientado al análisis de deformaciones con reorganización celular. Los núcleos vienen representados por nodos que forman una malla triangular, mientras que las contornos (membranas y córtex) forman una malla poligonal de vértices. Las dos mallas se acoplan a través de una restricción cinemática que puede ser relajada de forma controlada. El estudio hace especial hincapié en los cambios de conectividad, tanto debidos a la reorganización celular como el remodelado del citoesqueleto. Estas situaciones se abordan a través de una longitud de referencia variable y aplicando un Mapeo con Conservación de Equilibrio (EPM) que minimiza el error en el equilibrio nodal y en los vértices. La técnica resultante puede ser adaptada progresivamente a través de un parámetro, dando lugar a un modelo exclusivamente de vértices o a uno de centros. Sus propiedades se ilustran en simulaciones de monocapas sujetas a una extensión impuesta y durante el proceso de cicatrizado de heridas. La evolución de las fuerzas y los efectos del EPM durante el remodelado se analizan en estos ejemplos.
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Levis, Demian. "Two-dimensional Spin Ice and the Sixteen-Vertex Model." Phd thesis, Université Pierre et Marie Curie - Paris VI, 2012. http://tel.archives-ouvertes.fr/tel-00763350.
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Cette thèse présente une étude complète des propriétés statiques et dynamiques du modèle à seize vertex en 2D, une version simplifiée de la glace de spin avec interactions dipolaires. Après une discussion générale sur le magnétisme frustré, et la glace de spin en particulier, on justifie l'introduction de notre modèle pour étudier le comportement collectif de la glace de spin. On utilise un algorithme de Monte Carlo à temps continu avec une dynamique locale qui nous permet d'analyser les phases d'équilibre et les propriétés critiques du modèle 2D. On compare nos résutats avec les resultats obtenus dans les cas où le système est intégrable. On définit ensuite le modèle sur des arbres orientés et on applique une approximation du type Bethe-Peierls. Afin de discuter le domaine de validité de cette approche, on compare les résultats ainsi obtenus avec les résultats exacts et numériques obtenus pour le modèle 2D. L'apparition récente des glaces de spin artificielles suggère un certain choix des paramètres du modèle. On montre que le modèle à seize vertex décrit de façon précise la thermodynamique de la glace de spin artificielle. On présente en détail le diagramme de phase et la nature des phases d'équilibre du modèle à seize vertex. Afin d' inclure l'effet des fluctuations thermiques responsables de apparaition de défauts ponc- tuels dans la glace de spin, on construit une extension stochastique du modèle intégrable à six vertex. On étudie, par l'intermédiaire de simulations Monte Carlo, comment le système s'ordonne dans le temps après différentes trempes. On analyse l'évolution de la densité de défauts et on iden- tifie les mécanismes dynamiques qui pilotent la relaxation vers ses différentes phases d'équilibre. On montre ainsi que la dynamique donne lieu à du "coarsening" et qu'elle vérifie l'hypothèse de "scaling" dynamique. On discute le rôle des défauts topologiques étendus et ponctuels présents dans le système au cours de l'évolution. Finalement, on étudie la présence d'un régime dynamique où le système reste gelé pendant de longues périodes de temps, ce qui à été observé dans la glace de spin dipolaire en 3D.
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Smith, Aaron. "Vertex model approaches to epithelial tissues in developmental systems." Thesis, University of Oxford, 2012. http://ora.ox.ac.uk/objects/uuid:4d19f232-764c-4e27-bca9-d2ede0ec2db9.
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The purpose of this thesis is to develop a vertex model framework that can be used to perform computational experiments related to the dynamics of epithelial tissues in developmental systems. We focus on three example systems: the Drosophila wing imaginal disc, the Drosophila epidermis and the visceral endoderm of the mouse embryo. Within these systems, key questions pertaining to size-control mechanisms and coordination of cell migration remain unanswered and are amenable to computational testing. The vertex model presented here builds upon existing frameworks in three key ways. Firstly, we include novel force terms, representing, for example, the reaction of a cell to being compressed and its shape becoming distorted during a highly dynamic process such as cell migration. Secondly, we incorporate a model of diffusing morphogenetic growth factors within the vertex framework, using an arbitrary Lagrangian-Eulerian formulation of the diffusion equation and solving with the finite-element method (FEM). Finally, we implement the vertex model on the surface of an ellipsoid, in order to simulate cell migration in the mouse embryo. Throughout this thesis, we validate our model by running simple simulations. We demonstrate convergence properties of the FEM scheme and discuss how the time taken to solve the system scales with tissue size. The model is applied to biological systems and its utility demonstrated in several contexts. We show that when growth is dependent on morphogen concentration in the Drosophila wing disc, proliferation occurs preferentially in regions of high concentration. In the Drosophila epidermis, we show that a recently proposed mechanism of compartment size-control, in which a growth-factor is released in limited amounts, is viable. Finally, we examine the phenomenon of rosettes in the mouse embryo, which occur when five or more cells meet at a common vertex. We show, by running simulations both with and without rosettes, that they are crucial facilitators of ordered migration, and are thus critical in the patterning of the early embryo.
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Schurig, Michael. "The Vertex effect in polycrystalline materials simulation, a macroscopic model, and structural application /." [S.l.] : [s.n.], 2006. http://diglib.uni-magdeburg.de/Dissertationen/2006/micschurig.htm.
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Farhadifar, Reza. "Dynamics of Cell Packing and Polar Order in Developing Epithelia." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2010. http://nbn-resolving.de/urn:nbn:de:bsz:14-ds-1244035271841-50183.
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During development, organs with different shape and functionality form from a single fertilized egg cell. Mechanisms that control shape, size and morphology of tissues pose challenges for developmental biology. These mechanisms are tightly controlled by an underlying signaling system by which cells communicate to each other. However, these signaling networks can affect tissue size and morphology through limited processes such as cell proliferation, cell death and cell shape changes,which are controlled by cell mechanics and cell adhesion. One example of such a signaling system is the network of interacting proteins that control planar polarization of cells. These proteins distribute asymmetrically within cells and their distribution in each cell determines of the polarity of the neighboring cells. These proteins control the pattern of hairs in the adult Drosophila wing as well as hexagonal repacking of wing cells during development. Planar polarity proteins also control developmental processes such as convergent-extension. We present a theoretical study of cell packing geometry in developing epithelia. We use a vertex model to describe the packing geometry of tissues, for which forces are balanced throughout the tissue. We introduce a cell division algorithm and show that repeated cell division results in the formation of a distinct pattern of cells, which is controlled by cell mechanics and cell-cell interactions. We compare the vertex model with experimental measurements in the wing disc of Drosophila and quantify for the first time cell adhesion and perimeter contractility of cells. We also present a simple model for the dynamics of polarity order in tissues. We identify a basic mechanism by which long-range polarity order throughout the tissue can be established. In particular we study the role of shear deformations on polarity pattern and show that the polarity of the tissue reorients during shear flow. Our simple mechanisms for ordering can account for the processes observed during development of the Drosophila wing.
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Ekstrand, Joel. "Going Round in Circles : From Sigma Models to Vertex Algebras and Back." Doctoral thesis, Uppsala universitet, Teoretisk fysik, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-159918.
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In this thesis, we investigate sigma models and algebraic structures emerging from a Hamiltonian description of their dynamics, both in a classical and in a quantum setup. More specifically, we derive the phase space structures together with the Hamiltonians for the bosonic two-dimensional non-linear sigma model, and also for the N=1 and N=2 supersymmetric models. A convenient framework for describing these structures are Lie conformal algebras and Poisson vertex algebras. We review these concepts, and show that a Lie conformal algebra gives a weak Courant–Dorfman algebra. We further show that a Poisson vertex algebra generated by fields of conformal weight one and zero are in a one-to-one relationship with Courant–Dorfman algebras. Vertex algebras are shown to be appropriate for describing the quantum dynamics of supersymmetric sigma models. We give two definitions of a vertex algebra, and we show that these definitions are equivalent. The second definition is given in terms of a λ-bracket and a normal ordered product, which makes computations straightforward. We also review the manifestly supersymmetric N=1 SUSY vertex algebra. We also construct sheaves of N=1 and N=2 vertex algebras. We are specifically interested in the sheaf of N=1 vertex algebras referred to as the chiral de Rham complex. We argue that this sheaf can be interpreted as a formal quantization of the N=1 supersymmetric non-linear sigma model. We review different algebras of the chiral de Rham complex that one can associate to different manifolds. In particular, we investigate the case when the manifold is a six-dimensional Calabi–Yau manifold. The chiral de Rham complex then carries two commuting copies of the N=2 superconformal algebra with central charge c=9, as well as the Odake algebra, associated to the holomorphic volume form.
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Farhadifar, Reza. "Dynamics of Cell Packing and Polar Order in Developing Epithelia." Doctoral thesis, Technische Universität Dresden, 2009. https://tud.qucosa.de/id/qucosa%3A23750.
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During development, organs with different shape and functionality form from a single fertilized egg cell. Mechanisms that control shape, size and morphology of tissues pose challenges for developmental biology. These mechanisms are tightly controlled by an underlying signaling system by which cells communicate to each other. However, these signaling networks can affect tissue size and morphology through limited processes such as cell proliferation, cell death and cell shape changes,which are controlled by cell mechanics and cell adhesion. One example of such a signaling system is the network of interacting proteins that control planar polarization of cells. These proteins distribute asymmetrically within cells and their distribution in each cell determines of the polarity of the neighboring cells. These proteins control the pattern of hairs in the adult Drosophila wing as well as hexagonal repacking of wing cells during development. Planar polarity proteins also control developmental processes such as convergent-extension. We present a theoretical study of cell packing geometry in developing epithelia. We use a vertex model to describe the packing geometry of tissues, for which forces are balanced throughout the tissue. We introduce a cell division algorithm and show that repeated cell division results in the formation of a distinct pattern of cells, which is controlled by cell mechanics and cell-cell interactions. We compare the vertex model with experimental measurements in the wing disc of Drosophila and quantify for the first time cell adhesion and perimeter contractility of cells. We also present a simple model for the dynamics of polarity order in tissues. We identify a basic mechanism by which long-range polarity order throughout the tissue can be established. In particular we study the role of shear deformations on polarity pattern and show that the polarity of the tissue reorients during shear flow. Our simple mechanisms for ordering can account for the processes observed during development of the Drosophila wing.
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Jordan, Alex 1979. "A Super Version of Zhu's Theorem." Thesis, University of Oregon, 2008. http://hdl.handle.net/1794/8283.
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vii, 41 p. A print copy of this thesis is available through the UO Libraries. Search the library catalog for the location and call number.We generalize a theorem of Zhu relating the trace of certain vertex algebra representations and modular invariants to the arena of vertex super algebras. The theorem explains why the space of simple characters for the Neveu-Schwarz minimal models NS( p, q ) is modular invariant. It also expresses negative products in terms of positive products, which are easier to compute. As a consequence of the main theorem, the subleading coefficient of the singular vectors of NS( p, q ) is determined for p and q odd. An interesting family of q -series identities is established. These consequences established here generalize results of Milas in this field.
Adviser: Arkady Vaintrob
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Giering, Kay-Uwe [Verfasser], and Manfred [Akademischer Betreuer] Salmhofer. "Self-energy flows and the frequency-dependent interaction vertex in the two-dimensional repulsive Hubbard model / Kay-Uwe Giering ; Betreuer: Manfred Salmhofer." Heidelberg : Universitätsbibliothek Heidelberg, 2012. http://d-nb.info/1179784901/34.
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Dritsa, Christina Anna. "Design of the Micro Vertex Detector of the CBM experiment : development of a detector response model and feasibility studies of open charm measurement." Strasbourg, 2011. http://www.theses.fr/2011STRA6239.
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L'expérience CBM (Compressed Baryonic Matter), l'une des expériences majeures du futur accélérateur FAIR (Darmstadt, Allemagne), a pour objectif d'étudier le diagramme des phases de la matière nucléaire dans la région des hautes densités baryoniques nettes et des températures modérées. Un des principaux thèmes de physique de cette expérience est l'étude de la production et de la propagation des particules à charme ouvert, comme les mésons D (particules constituées d'un quark charmé et d'un quark léger), dans les collisions d'ions lourds. La mesure de ces mésons charmés nécessite l’utilisation d’un détecteur de vertex d’excellente précision. La présente thèse est une contribution à la conception et au développement de ce détecteur, appelé MVD (Micro Vertex Detector). Elle porte sur trois aspects principaux. Le premier, concerne la caractérisation expérimentale de la réponse des capteurs MAPS (Monolithic Active Pixel Sensors), constituant les stations du détecteur MVD, au passage des particules chargées. Le second, porte sur le développement d'un modèle permettant de décrire de façon réaliste la réponse du détecteur MVD. En fin, le troisième aspect consiste en une étude détaillée de la faisabilité des mesures des particules à charme ouvert dans les collisions noyau-noyau. Les résultats obtenus montrent que la mesure des particules à charme ouvert est faisable et permettent d’évaluer les performances attendues et les limites de l’expérienceThe CBM experiment (Compressed Baryonic Matter), one of the main experiments of the future FAIR accelerator facility (Darmstadt, Germany), aims in studying the phase diagram of nuclear matter in the region of high baryonic densities and moderate temperatures. Among the core physics goals is the study of the production and propagation of open charm particles, like D-mesons (particles containing one charm quark and one light quark) in heavy ion collisions. The measurements of these charmed mesons require the use of an excellent precision vertex detector. The present thesis is a contribution to the design and development of this detection device called MVD (Micro Vertex Detector). It is focused on three different parts. The first one concerns the experimental characterisation of the response of MAPS (Monolithic Active Pixel Sensors) sensors, composing the MVD detector stations, to the passage of charged particles. The second deals with the development of a realistic detector response model for the MVD detector. The last part focuses on a detailed feasibility study of open charm particle measurements in heavy ion collisions. The results demonstrate the feasibility of open charm particle measurements and allow assessing the expected performances and the limitations of the experiment
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Brunn, Ondřej. "Magnetické fáze umělého spinového ledu na čtvercové mřížce." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2019. http://www.nusl.cz/ntk/nusl-402646.
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Umělé spinové systémy jsou vhodným nástrojem pro zkoumání a ovlivňování neobvyklých exotických nízko-energiových stavů přímo v reálném prostoru. Experimentální realizace těchto systémů jsou založeny na výrobě vzájemně interagujících nano-magnetů uspořádaných do požadované geometrie. Prvním a asi i nejvíce studovaným umělým systémem je prostá čtvercová mřížka. V této práci se zabýváme modifikováním této čtvercové geometrie, které umožní zachycení různých magnetických fází založených na modelech ledu. Výsledky ukazují, že vhodným nastaveném této modifikace lze realizovat různé magnetické fáze, včetně neuspořádané spinové kapalné fáze s uvězněnými magnetickými kvazičásticemi (magnetickými monopóly).
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Almeida, Eduardo da Silva. "Limites de unitariedade para vértices quárticos anômalos." Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/43/43134/tde-03052018-135121/.
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Neste trabalho consideramos extensões do Modelo Padrão contendo vértices quárticos anômalos parametrizados por operadores efetivos de dimensão oito. Estes alteram o comportamento das amplitudes do tipo VV VV , onde V pode ser o fóton, o bóson Z, o bóson W ou o Higgs. Para essa extensão ser consistente, ela tem que obedecer o teorema ótico. Entretanto, as amplitudes geradas por estes operadores efetivos tendem a aumentar conforme a energia do centro de massa aumenta. Estudaremos o comportamento dessas amplitudes e determinaremos se há violação de unitariedade. Para isso utilizamos também o formalismo da base de helicidade.In this work we consider Standard Model extensions containing anomalous quartic vertex parametrized by effective dimension-eight operators. These modify the behaviour of the scat- tering amplitudes VV VV , where V can be photon, Z boson, W boson and Higgs. To this extension be consistent, it has to obey the optical theorem. However, the amplitudes generated by these effective operators tends to grow as the center of mass energy increase. We will study the behaviour of these amplitudes and we will determine if there is unitarity violation. For this it was also used the helicity base formalism.
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Schwenker, Benjamin [Verfasser], Ariane [Akademischer Betreuer] Frey, and Arnulf [Akademischer Betreuer] Quadt. "Development and validation of a model for the response of the Belle II vertex detector / Benjamin Schwenker. Gutachter: Ariane Frey ; Arnulf Quadt. Betreuer: Ariane Frey." Göttingen : Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2014. http://d-nb.info/1060543133/34.
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Staple, Douglas. "Understanding Mechanics and Polarity in Two-Dimensional Tissues." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2012. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-85622.
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During development, cells consume energy, divide, rearrange, and die. Bulk properties such as viscosity and elasticity emerge from cell-scale mechanics and dynamics. Order appears, for example in patterns of hair outgrowth, or in the predominately hexagonal pattern of cell boundaries in the wing of a fruit fly. In the past fifty years, much progress has been made in understanding tissues as living materials. However, the physical mechanisms underlying tissue-scale behaviour are not completely understood. Here we apply theories from statistical physics and fluid dynamics to understand mechanics and order in two-dimensional tissues. We restrict our attention to the mechanics and dynamics of cell boundaries and vertices, and to planar polarity, a type of long-ranged order visible in anisotropic patterns of proteins and hair outgrowth.
Our principle tool for understanding mechanics and dynamics is a vertex model where cell shapes are represented using polygons. We analytically derive the ground-state diagram of this vertex model, finding it to be dominated by the geometric requirement that cells be polygons, and the topological requirement that those polygons tile the plane. We present a simplified algorithm for cell division and growth, and furthermore derive a dynamic equation for the vertex model, which we use to demonstrate the emergence of quasistatic behaviour in the limit of slow growth. All our results relating to the vertex model are consistent with and build off past calculations and experiments.
To investigate the emergence of planar polarity, we develop quantification methods for cell flow and planar polarity based on confocal microscope images of developing fly wings. We analyze cell flow using a velocity gradient tensor, which is uniquely decomposed into terms corresponding to local compression, shear, and rotations. We argue that a pattern in an inhomogeneously flowing tissue will necessarily be reorganized, motivating a hydrodynamic theory of polarity reorientation. Using such a coarse-grained theory of polarity reorientation, we show that the quantified patterns of shear and rotation in the wing are consistent with the observed polarity reorganization, and conclude that cell flow reorients planar polarity in the wing of the fruit fly. Finally, we present a cell-scale model of planar polarity based on the vertex model, unifying the themes of this thesis.
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Nestor-Bergmann, Alexander. "Relating cell shape, mechanical stress and cell division in epithelial tissues." Thesis, University of Manchester, 2018. https://www.research.manchester.ac.uk/portal/en/theses/relating-cell-shape-mechanical-stress-and-cell-division-in-epithelial-tissues(ebf1bce8-ca35-4f5a-8be9-f2e19c96e20d).html.
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The development and maintenance of tissues and organs depend on the careful regulation and coordinated motion of large numbers of cells. There is substantial evidence that many complex tissue functions, such as cell division, collective cell migration and gene expression, are directly regulated by mechanical forces. However, relatively little is known about how mechanical stress is distributed within a tissue and how this may guide biochemical signalling. Working in the framework of a popular vertex-based model, we derive expressions for stress tensors at the cell and tissue level to build analytic relationships between cell shape and mechanical stress. The discrete vertex model is upscaled, providing exact expressions for the bulk and shear moduli of disordered cellular networks, which bridges the gap to traditional continuum-level descriptions of tissues. Combining this theoretical work with new experimental techniques for whole-tissue stretching of Xenopus laevis tissue, we separate the roles of mechanical stress and cell shape in orienting and cueing epithelial mitosis. We find that the orientation of division is best predicted by the shape of tricellular junctions, while there appears to be a more direct role for mechanical stress as a mitotic cue.
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Wang, Zhituo. "La renormalisation constructive pour la théorie quantique des champs non commutative." Phd thesis, Université Paris Sud - Paris XI, 2011. http://tel.archives-ouvertes.fr/tel-00657010.
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Dans la partie principale de cette these on considère la theorie euclidienne constructive des champs. La théorie constructive (ou la renormalisation constructive) propose l'étude mathématiquement rigoureuse de l'existence et des propriétés non perturbatives de la théorie quantique des champs. Les méthodes traditionnelles de la théorie constructive sont les développements en amas et le groupe de renormalisation de Wilson. Mais il y a aussi des défauts de ces deux méthodes: premièrement, les techniques du développement en amas et de Mayer sont compliquées, donc sont difficiles à utiliser. Deuxièmement, ces méthodes ne peuvent pas s'appliquer pour les théories quantiques des champs noncommutatives, où il n'y a pas de localité sur l'espace et l'interaction est non-locale.Récemment une nouvelle méthode a été trouvée qui s'appelle loop vertex expansion (LVE), ou développement de vertex à boucle, qui est une combinaison de la technique des champs intermédiaires et de la formule des forêt (la formule de BKAR), qui peut résoudre ces deux problèmes avec succès.Avec cette méthode, on n'a pas besoin du développement de Mayer et le développement en amas est aussi simplifié. Et comme le terme d'interaction devient non-local aussi, cette méthode s'applique bien pour les théories quantique des champs noncommutatives, par exemple, le modèle de Grosse-Wulkenhaar, qui est un modèle λΦ4 avec un potentiel harmonique dans l'espace de Moyal. C'est le premier modèle de la théorie quantique des champs noncommutative qui est renormalisable. De plus, la fonction β est nulle quand on attend le point fixe ultraviolet de cette théorie. Donc c'est aussi un modèle naturel qu'on peut construire non-perturbativement.Dans cette thèse nous allons construire le modèle de Grosse-Wulkenhaar à 2-dimensions avec la LVE.Dans le reste de cette these nous considerons aussi la construction des varieties noncommutative par les états coherents et les polynomes topological pour les graphes de Feyman dans les théorie commutatives et noncommutatives.
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Weigel, Martin. "Vertex Models on Random Graphs." Doctoral thesis, Universitätsbibliothek Leipzig, 2004. http://nbn-resolving.de/urn:nbn:de:bsz:15-qucosa-37308.
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Diese Arbeit befaßt sich mit der Koppelung von Vertex-Modellen an die planaren $\phi^4$-Zufallsgraphen des Zugangs zur Quantengravitation über dynamische Polygonifizierungen. Das betrachtete System hat eine doppelte Bedeutung, einerseits als die Koppelung einer konformen Feldtheorie mit zentraler Ladung $C=1$ an zweidimensionale Euklidische Quantengravitation, andererseits als Anwendung von geometrischer, "annealed" Unordnung auf ein prototypisches Modell der statistischen Mechanik. Da das Modell mit Hilfe einer großangelegten Reihe von Monte Carlo Simulationen untersucht wird, müssen entsprechende Techniken für die Simulation von dynamischen Quadrangulierungen bzw. die dualen $\phi^4$-Graphen entwickelt werden. Hierzu werden verschiedene Algorithmen und die dazugehörigen Züge vorgeschlagen und hinsichtlich ihrer Ergodizität und Effizienz untersucht. Zum Vergleich mit exakten Ergebnissen werden die Verteilung der Koordinationszahlen bzw. bestimmte Analoga davon konstruiert. Für Simulationen des $F$-Modells auf $\phi^4$-Zufallsgraphen wird ein Ordnungsparameter für den antiferroelektrischen Phasenübergang mit Hilfe einer Plakettenspindarstellung formuliert. Ausführliche "finite-size scaling"-Analysen des Kosterlitz-Thouless-Phasenübergangs des $F$-Modells auf dem Quadratgitter und auf Zufallsgraphen werden vorgestellt und die Positionen der jeweiligen kritischen Punkte sowie die dazugehörigen kritischen Exponenten werden bestimmt. Die Rückreaktion des Vertex-Modells auf die Zufallsgraphen wird in Form der Koordinationszahlverteilung, der Verteilung der "Baby-Universen" und dem daraus resultierenden String-Suszeptibilitäts-Exponenten sowie durch die geometrische Zweipunktfunktion analysiert, die eine Schätzung der intrinsischen Hausdorff-Dimension des gekoppelten Systems liefertIn this thesis, the coupling of ice-type vertex models to the planar $\phi^4$ random graphs of the dynamical polygonifications approach to quantum gravity is considered. The investigated system has a double significance as a conformal field theory with central charge $C=1$ coupled to two-dimensional Euclidean quantum gravity and as the application of a special type of annealed connectivity disorder to a prototypic model of statistical mechanics. Since the model is analyzed by means of large-scale Monte Carlo simulations, suitable simulation techniques for the case of dynamical quadrangulations and the dual $\phi^4$ random graphs have to be developed. Different algorithms and the associated update moves are proposed and investigated with respect to their ergodicity and performance. For comparison to exact results, the co-ordination number distribution of the dynamical polygonifications model, or certain analogues of it, are constructed. For simulations of the 6-vertex $F$ model on $\phi^4$ random graphs, an order parameter for its anti-ferroelectric phase transitions is constructed in terms of a "plaquette spin" representation. Extensive finite-size scaling analyses of the Kosterlitz-Thouless point of the square-lattice and random graph $F$ models are presented and the locations of the critical points as well as the corresponding critical exponents are determined. The back-reaction of the coupled vertex model on the random graphs is investigated by an analysis of the co-ordination number distribution, the distribution of "baby universes" and the string susceptibility exponent as well as the geometric two-point function, yielding an estimate for the internal Hausdorff dimension of the coupled system
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Pittau, Lorenzo. "Quantum groups and vertex models." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2012. http://amslaurea.unibo.it/4118/.
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Nella tesi vengono presentate alcune relazioni fra gruppi quantici e modelli reticolari. In particolare si associa un modello vertex a una rappresentazione di un'algebra inviluppante quantizzata affine e si mostra che, specializzando il parametro quantistico ad una radice dell'unità, si manifestano speciali simmetrie.
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Aliee, Maryam. "Dynamics and mechanics of compartment boundaries in developing tissues." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2013. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-113236.
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During development of tissues, cells collectively organize to form complex patterns and morphologies. A general feature of many developing epithelia is their distinct organization into cellular compartments of different cell lineages. The interfaces between these compartments, called compartment boundaries, maintain straight and sharp morphologies. The interfaces play key roles in tissue development and pattern formation. An important model system to study the morphology of compartment boundaries during development is the wing disc of the fruit fly. Two compartment boundaries exist in the fly wing disc, the anteroposterior (AP) boundary and the dorsoventral (DV) boundary. A crucial question is how compartment boundaries are shaped and remain stable during growth.
In this work, we discuss the dynamics and mechanisms of compartment boundaries in developing epithelia. We analyze the general features of interfacial phenomena in coarse- grained models of passive and active fluids. We introduce a continuum description of tissues with two cell types. This model allows us to study the propagation of interfaces due to the interplay of cell dynamics and tissue mechanics. We also use a vertex model to describe cellular compartments in growing epithelia. The vertex model accounts for cell mechanics and describes a 2D picture of tissues where the network of adherens junctions characterizes cell shapes. We use this model to study the general physical mechanisms by which compartment boundaries are shaped. We quantify the stresses in the cellular network and discuss how cell mechanics and growth influence the stress profile. With the help of the anisotropic stress profile near the interfaces we calculate the interfacial tension. We show that cell area pressure, cell proliferation rate, orientation of cell division, cell elongation created by external stress, and cell bond tension all have distinct effects on the morphology of interfaces during tissue growth. Furthermore, we investigate how much different mechanisms contribute to the effective interfacial tension.
We study the mechanisms shaping the DV boundary in wing imaginal disc at different stages during the development. We analyze the images of wing discs to quantify the roughness of the DV boundary and average cell elongation in its vicinity. We quantify increased cell bond tension along the boundary and analyze the role of localized reduction in cell proliferation on the morphology of the DV boundary. We use experimentally determined values for cell bond tension, cell elongation and bias in orientation of cell division in simulations of tissue growth in order to reproduce the main features of the time-evolution of the DV boundary shape.
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Deveaux, Christina Anna [Verfasser], Fouad [Akademischer Betreuer] Rami, and Peter [Akademischer Betreuer] Senger. "Design of the micro vertex detector of the CBM experiment: development of a detector response model and feasibility studies of open charm measurement / Christina Anna Dritsa. Gutachter: Fouad Rami ; Peter Senger. Betreuer: Fouad Rami ; Peter Senger." Frankfurt am Main : Univ.-Bibliothek Frankfurt am Main, 2014. http://d-nb.info/105346830X/34.
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Koessler, Denise Renee. "A Predictive Model for Secondary RNA Structure Using Graph Theory and a Neural Network." Digital Commons @ East Tennessee State University, 2010. https://dc.etsu.edu/etd/1684.
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In this work we use a graph-theoretic representation of secondary RNA structure found in the database RAG: RNA-As-Graphs. We model the bonding of two RNA secondary structures to form a larger structure with a graph operation called merge. The resulting data from each tree merge operation is summarized and represented by a vector. We use these vectors as input values for a neural network and train the network to recognize a tree as RNA-like or not based on the merge data vector.
The network correctly assigned a high probability of RNA-likeness to trees identified as RNA-like in the RAG database, and a low probability of RNA-likeness to those classified as not RNA-like in the RAG database. We then used the neural network to predict the RNA-likeness of all the trees of order 9. The use of a graph operation to theoretically describe the bonding of secondary RNA is novel.
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Hupka, Dušan. "Techniky "level of detail" v knihovně OpenSceneGraph." Master's thesis, Vysoké učení technické v Brně. Fakulta informačních technologií, 2014. http://www.nusl.cz/ntk/nusl-236099.
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Present graphic requires a lot of optimizations of rendering techniques and mathematical calculations. It is caused by increased requirements of scene's visualization. One of scene's optimizing techniques is the Level of detail. This thesis is focused on methods used by LOD in OpenSceneGraph and OpenGL library. Next it will be described how to choose the right level of detail in a scene. Later it will be explained how to simplify 3D models. These techniques will be implemented in converting tool and demonstrating application. Methods for simplify 3D models will be tested for their speed and quality.
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Chen, Xiaochen. "Tracking vertex flow on 3D dynamic facial models." Diss., Online access via UMI:, 2008.
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Melotti, Paul. "Modèles intégrables de spins, vertex et boucles." Thesis, Sorbonne université, 2019. http://www.theses.fr/2019SORUS258.
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Cette thèse porte sur divers problèmes de mécanique statistique, liée à l'étude des modèles intégrables. Dans ces modèles, l'existence de symétries particulières, exprimées par exemple par les équations de Yang-Baxter ou transformations "triangle-étoile'', permettent de donner des formules exactes pour les observables d'intérêt. Dans un premier temps, nous étudions la transformation triangle-étoile du modèle d'Ising, reformulée par Kashaev en une équation d'évolution polynomiale. Nous montrons que cette évolution fait apparaître des objets combinatoires : les modèles de boucles C2(1). Nous montrons de plus des résultats de formes limites et des calculs d'énergie libre pour ces modèles de boucles. Dans un second temps, nous développons la compréhension du modèle des ``huit sommets'', qui généralise les modèles de glace. Nous montrons que dans le régime des fermions libres, ces modèles peuvent être compris via des modèles de dimères bipartis, et des fortes structures d'intégrabilité de ces derniers. Nous en déduisons des constructions de mesures de Gibbs et des corrélations en volume infini, notamment pour des régimes Z-invariants sur des graphes isoradiaux. Enfin, nous proposons des interprétations des équations de Yang-Baxter en géométrie discrète, via des plongements particuliers de graphesThis thesis deals with several problems in statistical mechanics, related to the study of integrable models. In these models, some particular symmetries, like those expressed by the Yang-Baxter equations or "star-triangle'' transformations, lead to the existence of exact formulas for observables of interest.In a first part, we study the star-triangle transformation of the Ising model, recast into a singe polynomial evolution equation by Kashaev. We show that this evolution creates combinatorial objects: C2(1) loop models. We show some limit shapes results and compute the free energy of these loop models. In a second part, we develop the study of the ``eight-vertex'' model, that generalises ice models. In the free-fermion regime, we translate these models into dimers on a bipartite graph, and use the strong integrability structures of these. We deduce the construction of Gibbs measures and correlations in infinite volume, in particular for Z-invariant regimes on isoradial graphs. Finally, we suggest interpretations of the Yang-Baxter equations in discrete geometry, via particular embeddings of graphs
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Lange, Stefan. "On the evaluation of regional climate model simulations over South America." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät, 2015. http://dx.doi.org/10.18452/17342.
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Diese Dissertation beschäftigt sich mit regionaler Klimamodellierung über Südamerika, der Analyse von Modellsensitivitäten bezüglich Wolkenparametrisierungen und der Entwicklung neuer Methoden zur Modellevaluierung mithilfe von Klimanetzwerken. Im ersten Teil untersuchen wir Simulationen mit dem COnsortium for Small scale MOdeling model in CLimate Mode (COSMO-CLM) und stellen die erste umfassende Evaluierung dieses dynamischen regionalen Klimamodells über Südamerika vor. Dabei untersuchen wir insbesondere die Abhängigkeit simulierter tropischer Niederschläge von Parametrisierungen subgitterskaliger cumuliformer und stratiformer Wolken und finden starke Sensitivitäten bezüglich beider Wolkenparametrisierungen über Land. Durch einen simultanen Austausch der entsprechenden Schemata gelingt uns eine beträchtliche Reduzierung von Fehlern in klimatologischen Niederschlags- und Strahlungsmitteln, die das COSMO-CLM über tropischen Regionen für lange Zeit charakterisierten. Im zweiten Teil führen wir neue Metriken für die Evaluierung von Klimamodellen bezüglich räumlicher Kovariabilitäten ein. Im Kern bestehen diese Metriken aus Unähnlichkeitsmaßen für den Vergleich von simulierten mit beobachteten Klimanetzwerken. Wir entwickeln lokale und globale Unähnlichkeitsmaße zum Zwecke der Darstellung lokaler Unähnlichkeiten in Form von Fehlerkarten sowie der Rangordnung von Modellen durch Zusammenfassung lokaler zu globalen Unähnlichkeiten. Die neuen Maße werden dann für eine vergleichende Evaluierung regionaler Klimasimulationen mit COSMO-CLM und dem Statistical Analogue Resampling Scheme über Südamerika verwendet. Dabei vergleichen wir die sich ergebenden Modellrangfolgen mit solchen basierend auf mittleren quadratischen Abweichungen klimatologischer Mittelwerte und Varianzen und untersuchen die Abhängigkeit dieser Rangfolgen von der betrachteten Jahreszeit, Variable, dem verwendeten Referenzdatensatz und Klimanetzwerktyp.This dissertation is about regional climate modeling over South America, the analysis of model sensitivities to cloud parameterizations, and the development of novel model evaluation techniques based on climate networks. In the first part we examine simulations with the COnsortium for Small scale MOdeling weather prediction model in CLimate Mode (COSMO-CLM) and provide the first thorough evaluation of this dynamical regional climate model over South America. We focus our analysis on the sensitivity of simulated tropical precipitation to the parameterizations of subgrid-scale cumuliform and stratiform clouds. It is shown that COSMO-CLM is strongly sensitive to both cloud parameterizations over tropical land. Using nondefault cumulus and stratus parameterization schemes we are able to considerably reduce long-standing precipitation and radiation biases that have plagued COSMO-CLM across tropical domains. In the second part we introduce new performance metrics for climate model evaluation with respect to spatial covariabilities. In essence, these metrics consist of dissimilarity measures for climate networks constructed from simulations and observations. We develop both local and global dissimilarity measures to facilitate the depiction of local dissimilarities in the form of bias maps as well as the aggregation of those local to global dissimilarities for the purposes of climate model intercomparison and ranking. The new measures are then applied for a comparative evaluation of regional climate simulations with COSMO-CLM and the STatistical Analogue Resampling Scheme (STARS) over South America. We compare model rankings obtained with our new performance metrics to those obtained with conventional root-mean-square errors of climatological mean values and variances, and analyze how these rankings depend on season, variable, reference data set, and climate network type.
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Liu, Ying Ph D. Massachusetts Institute of Technology Department of Electrical Engineering and Computer Science. "Probabilistic graphical models : distributed inference and learning models with small feedback vertex sets." Thesis, Massachusetts Institute of Technology, 2014. http://hdl.handle.net/1721.1/89994.
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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2014.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 167-173).
In undirected graphical models, each node represents a random variable while the set of edges specifies the conditional independencies of the underlying distribution. When the random variables are jointly Gaussian, the models are called Gaussian graphical models (GGMs) or Gauss Markov random fields. In this thesis, we address several important problems in the study of GGMs. The first problem is to perform inference or sampling when the graph structure and model parameters are given. For inference in graphs with cycles, loopy belief propagation (LBP) is a purely distributed algorithm, but it gives inaccurate variance estimates in general and often diverges or has slow convergence. Previously, the hybrid feedback message passing (FMP) algorithm was developed to enhance the convergence and accuracy, where a special protocol is used among the nodes in a pseudo-FVS (an FVS, or feedback vertex set, is a set of nodes whose removal breaks all cycles) while standard LBP is run on the subgraph excluding the pseudo-FVS. In this thesis, we develop recursive FMP, a purely distributed extension of FMP where all nodes use the same integrated message-passing protocol. In addition, we introduce the subgraph perturbation sampling algorithm, which makes use of any pre-existing tractable inference algorithm for a subgraph by perturbing this algorithm so as to yield asymptotically exact samples for the intended distribution. We study the stationary version where a single fixed subgraph is used in all iterations, as well as the non-stationary version where tractable subgraphs are adaptively selected. The second problem is to perform model learning, i.e. to recover the underlying structure and model parameters from observations when the model is unknown. Families of graphical models that have both large modeling capacity and efficient inference algorithms are extremely useful. With the development of new inference algorithms for many new applications, it is important to study the families of models that are most suitable for these inference algorithms while having strong expressive power in the new applications. In particular, we study the family of GGMs with small FVSs and propose structure learning algorithms for two cases: 1) All nodes are observed, which is useful in modeling social or flight networks where the FVS nodes often correspond to a small number of high-degree nodes, or hubs, while the rest of the networks is modeled by a tree. 2) The FVS nodes are latent variables, where structure learning is equivalent to decomposing an inverse covariance matrix (exactly or approximately) into the sum of a tree-structured matrix and a low-rank matrix. We perform experiments using synthetic data as well as real data of flight delays to demonstrate the modeling capacity with FVSs of various sizes.
by Ying Liu.
Ph. D.
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Hobuß, Konstantin [Verfasser]. "Spin chains and vertex models based on superalgebras / Konstantin Hobuß." Hannover : Gottfried Wilhelm Leibniz Universität Hannover, 2019. http://d-nb.info/1204458871/34.
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Dimitrov, Evgeni (Evgeni Simeonov). "Scaling limits of random plane partitions and six-vertex models." Thesis, Massachusetts Institute of Technology, 2018. http://hdl.handle.net/1721.1/117872.
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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Mathematics, 2018.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 235-239).
We present a collection of results about the scaling limits of several models from integrable probability. Our first result concerns the asymptotic behavior of the bottom slice of a Hall-Littlewood random plane partition. We show the latter concentrates around a limit shape and in two different scaling regimes identify the fluctuations around this shape with the GUE Tracy- Widom distribution and the narrow wedge initial data solution to the Kardar-Parisi-Zhang (KPZ) equation. The second result concerns the limiting behavior of a class of six-vertex models in the quadrant, and we obtain the GUE-corners process as a scaling limit for this class near the boundary. Our final result, joint with Ivan Corwin, demonstrates the (long predicted) transversal 2/3 critical exponent for the height functions of the stochastic sixvertex model and asymmetric simple exclusion process (ASEP). The algebraic parts of our arguments involve the construction and use of degenerations and modifications of the Macdonald difference operators to obtain rich families of observables for the models we consider. These formulas are in terms of multiple contour integrals and provide a direct access to quantities of interest. The analytic parts of our arguments include the detailed asymptotic analysis of Fredholm determinants and contour integrals through steepest descent methods. An important aspect of our approach, is the combination of exact formulas with more probabilistic arguments, based on various Gibbs properties enjoyed by the models we study.
by Evgeni Dimitrov.
Ph. D.
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Vieira, Ricardo Soares. "Estudos sobre as equações de Bethe." Universidade Federal de São Carlos, 2015. https://repositorio.ufscar.br/handle/ufscar/7711.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
In this dissertation we made an analytic study of the Bethe Ansatz equations for the XXZ six vertex model with periodic boundary conditions. We had show that the Bethe Ansatz equations deduced from the algebraic and coordinate Bethe Ansatze are related by a conformal map. This allowed us to reduce the Bethe Ansatz equations to a system of polynomial equations. For the one, two and three magnon sectors, we succeeded in decouple these equations, so that the solutions could be expressed in terms of the roots of some self-inversive polynomials, Pa (z). Through new theorems deduced here about the distribution of the roots of self-inversive polynomials in the complex plane, we did a thorough analysis of the distribution of the Bethe roots for the two-magnon sector. This analysis allowed us to show that the Bethe Ansatz is indeed complete for this sector, except at some critical values of the anisotropy parameter A, in which the polynomials Pa (z) may have multiple roots. Finally, an unexpected connection between the Bethe Ansatz equations and the Salem polynomials was found and a new algorithm for search small Salem numbers was elaborated.
Nesta tese fizemos um estudo analítico das equações de Bethe para o modelo de seis vértices XXZ com condições de contorno periódicas. Mostramos que as equações de Bethe deduzidas pelo Ansatz algébrico estão relacionadas com as equações de Bethe do Ansatz de coordenadas por uma transformação conforme. Isso nos permitiu reduzir as equações de Bethe a um sistema de equações polinomiais. Para os setores de um, dois e três mágnons, mostramos que essas equações podem ser desacopladas, de modo que as suas soluções podem ser expressas em termos das raízes de certos polinómios auto-inversivos, Pa(z). Deduzimos aqui novos teoremas acerca da distribuição das raízes dos polinómios auto-inversivos no plano complexo, o que nos permitiu fazer uma análise minuciosa da distribuição das raízes de Bethe para o setor de dois mágnons. Esta análise nos permitiu mostrar que o Ansatz de Bethe é de fato completo para este setor, exceto para alguns valores críticos do parâmetro de anisotropia A, no qual os polinómios Pa(z) podem apresentar raízes múltiplas. Por fim, uma inesperada conexão entre as equações de Bethe e os polinómios de Salem foi encontrada e um novo algoritmo para se procurar por números de Salem pequenos foi elaborado.
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Pilch, Martin. "Simulace vlnění vody v reálném čase." Master's thesis, Vysoké učení technické v Brně. Fakulta informačních technologií, 2011. http://www.nusl.cz/ntk/nusl-236955.
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Task of this thesis is creation of real-time simulation of the water waves. It is implemented on Mac OS X platform using OpenGL. This thesis is based on height map surface. Heigh map is computed by suming of sinusoids with complex, time-based amplitudes. Fast Fourier transformation, Phillips spectrum and gauss random generator are used to solve this problem. The thesis is also implemented on iOS platform and optimized to run on mobile devices thanks to using programmable graphic pipeline and other drawing and computing optimizations.
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Minami, Kazuhiko. "The free energies of six-vertex models and the n-equivalence relation." American Institite of Physics, 2008. http://hdl.handle.net/2237/12026.
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Källén, Johan. "Twisting and Gluing : On Topological Field Theories, Sigma Models and Vertex Algebras." Doctoral thesis, Uppsala universitet, Teoretisk fysik, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-173225.
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This thesis consists of two parts, which can be read separately. In the first part we study aspects of topological field theories. We show how to topologically twist three-dimensional N=2 supersymmetric Chern-Simons theory using a contact structure on the underlying manifold. This gives us a formulation of Chern-Simons theory together with a set of auxiliary fields and an odd symmetry. For Seifert manifolds, we show how to use this odd symmetry to localize the path integral of Chern-Simons theory. The formulation of three-dimensional Chern-Simons theory using a contact structure admits natural generalizations to higher dimensions. We introduce and study these theories. The focus is on the five-dimensional theory, which can be understood as a topologically twisted version of N=1 supersymmetric Yang-Mills theory. When formulated on contact manifolds that are circle fibrations over a symplectic manifold, it localizes to contact instantons. For the theory on the five-sphere, we show that the perturbative part of the partition function is given by a matrix model. In the second part of the thesis, we study supersymmetric sigma models in the Hamiltonian formalism, both in a classical and in a quantum mechanical setup. We argue that the so called Chiral de Rham complex, which is a sheaf of vertex algebras, is a natural framework to understand quantum aspects of supersymmetric sigma models in the Hamiltonian formalism. We show how a class of currents which generate symmetry algebras for the classical sigma model can be defined within the Chiral de Rham complex framework, and for a six-dimensional Calabi-Yau manifold we calculate the equal-time commutators between the currents and show that they generate the Odake algebra.
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Lin, Kaisheng. "Motif counts, clustering coefficients and vertex degrees in models of random networks." Thesis, University of Oxford, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.497038.
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Rosato, Matthew J. "Applying conformal mapping to the vertex correspondence problem for 3D face models." Diss., Online access via UMI:, 2007.
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Valéry, Loïc. "Recherche de sgluons dans des états finals multitops avec le détecteur ATLAS auprès du LHC à √s = 8 TeV." Thesis, Clermont-Ferrand 2, 2014. http://www.theses.fr/2014CLF22470/document.
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En dépit de nombreuses confirmations expérimentales, le Modèle Standard, théorie décrivant les particules élémentaires et trois des interactions fondamentales souffre de difficultés théoriques et expérimentales. Ces dernières motivent l’existence d’une physique non décrite jusqu’alors : la Nouvelle Physique. Ce travail se focalise sur la recherche de gluons scalaires, appelés communément sgluons, nouvelles particules prédites dans plusieurs théories de Nouvelle Physique. Une étude phénoménologique considère les différents états finals (de un à quatre quarks top) et signatures (un ou deux leptons chargés) qui peuvent être engendrés par l’existence de sgluons. La sensibilité d’une expérience comme Atlas à ce signal est estimée et montre que l’un des états finals les plus prometteurs est celui contenant quatre quarks top, dans la signature à deux leptons porteurs de la même charge électrique (électron ou muon). La recherche de sgluons dans l’expérience Atlas s’appuie sur les états finals à quatre quarks top dans une signature à deux leptons porteurs de la même charge électrique, des jets étiquetés b et de l’énergie transverse manquante. Elle représente la première recherche mondiale de sgluons dans cet état final. Les principaux enjeux de l’analyse (estimation des bruits de fond, optimisation de la sélection, interprétation statistique) sont détaillés. La comparaison avec les données enregistrées pendant la première partie de l’année 2012 (L = 14:3 fb..1) ne montre pas d’excès significatif. La limite inférieure sur la masse du sgluon est alors de 0.80+0:02..0:03 TeV. L’extension de cette analyse avec le lot complet de données enregistrées en 2012 par Atlas est également présentée dans ce document et permet une sensibilité accrue jusqu’à des masses de sgluons de 0:94 0:03 TeV. Ce document présente également les analyses et résultats relatifs à des études de performances. La première s’attache au système de hautes tensions du calorimètre hadronique à tuiles du détecteur Atlas (TileCal). Elle conclut notamment, au regard des critères établis, que seuls 7 canaux de hautes tensions du TileCal (sur un total de 9852) ont un comportement problématique. La deuxième étude est liée à la réjection de l’effet d’empilement au moyen d’une sélection sur la variable JVF (Jet Vertex Fraction). L’efficacité de cette sélection, calculée dans les données et dans la simulation montre des différences, nécessitant l’apport d’une correction à la simulation. La détermination de facteurs correctifs et de leurs incertitudes systématiques associées est présentée dans ce documentDespite its experimental confirmations, the Standard Model, which describes both the elementary particles and three of the fundamental interactions, has some theoretical and experimental limitations. As a consequence of these limitations, a Physics not described in the context of the Standard Model could exist : the New Physics. This work focuses on the search for scalar gluons, commonly dubbed sgluons, predicted in various New Physics theories. A phenomenological study considers various final states (containing between two and four top quarks) and signatures (with one or two charged leptons) that could arise from sgluon production. The sensitivity of an Atlas-like experiment to this signal is estimated and the results indicate that one of the most promising final states contains four top quarks in a signature with two charged leptons (electron or muon) of the same electric charge. The search for sgluons within the Atlas experiment uses the previous results. Thus, it only investigates the 4-top topology in a signature containing two same-sign charged leptons, b-jets and missing transverse energy. It represents the first search ever for sgluons in this final state. The main steps of the analysis (background estimation, selection optimisation and statistical interpretation) are detailed. The comparison with the data recorded in the first months of 2012 (L = 14:3 fb..1) shows no significant excess and is interpreted in terms of a limit on the sgluon mass. The latter is found to be 0.80+0:02..0:03 TeV. The extension of this analysis to the full 2012 Atlas dataset is also presented in this document and shows an increased expected sensitivity to sgluon masses up to 0:94 0:03 TeV. Finally, this document also presents the analyses and results of performance studies. The first one is related to the high voltage system of the Atlas Tile Calorimeter (TileCal). The main conclusion is that only 7 channels out of the 9852 TileCal ones are fond to be problematic. The second study focuses on the rejection of the pile-up effect by the means of a selection applied on the so-called JVF (Jet Vertex Fraction) variable. The efficiency of this selection is computed both in data and simulation and shows some differences that have to be corrected in the simulation. The derivation of the correction factors and their associated systematic uncertainties is detailed in this document
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Anger, Philipp. "Probing Electroweak Gauge Boson Scattering with the ATLAS Detector at the Large Hadron Collider." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2014. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-151612.
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Electroweak gauge bosons as central components of the Standard Model of particle physics are well understood theoretically and have been studied with high precision at past and present collider experiments. The electroweak theory predicts the existence of a scattering process of these particles consisting of contributions from triple and quartic bosonic couplings as well as Higgs boson mediated interactions. These contributions are not separable in a gauge invariant way and are only unitarized in the case of a Higgs boson as it is described by the Standard Model. The process is tied to the electroweak symmetry breaking which introduces the longitudinal modes for the massive electroweak gauge bosons. A study of this interaction is also a direct verification of the local gauge symmetry as one of the fundamental axioms of the Standard Model. With the start of the Large Hadron Collider and after collecting proton-proton collision data with an integrated luminosity of 20.3/fb at a center-of-mass energy of 8 TeV with the ATLAS detector, first-ever evidence for this process could be achieved in the context of this work.
A study of leptonically decaying WWjj, same-electric-charge diboson production in association with two jets resulted in an observation of the electroweak WWjj production with same electric charge of the W bosons, inseparably comprising WW->WW electroweak gauge boson scattering contributions, with a significance of 3.6 standard deviations. The measured production cross section is in agreement with the Standard Model prediction.
In the course of a study for leptonically decaying WZ productions, methods for background estimation, the extraction of systematic uncertainties and cross section measurements were developed. They were extended and applied to the WZjj final state whereof the purely electroweakly mediated contribution is intrinsically tied to the scattering of all Standard Model electroweak gauge bosons: Wγ->WZ and WZ->WZ. Three charged leptons and a neutrino from the decay of the final state bosons allow inferences about the scattering process. A distinct signature is provided by the two accompanying tagging jets as remnants of the incoming quarks radiating the initial electroweak gauge bosons. The cross section of the electroweak WZjj production was measured to σ(fiducial, observed) = (0.63 +0.32 -0.28 (stat.) +0.41 -0.24 (syst.)) fb and was found to be consistent with the Standard Model prediction at next-to-leading order in perturbative quantum chromodynamics, σ(fiducial, theory) = (0.31 +0.03 -0.05) fb. Unfolded differential cross sections of kinematic variables sensitive to models of new physics were derived. Anomalous quartic electroweak gauge couplings are introduced as dimensionless coupling parameters of additional operators within an effective field theory approach. Constraints on the parameters of operators with dimension eight were set employing a unitarization prescription based on form factors.
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Casse, Jérôme. "Automates cellulaires probabilistes et processus itérés ad libitum." Thesis, Bordeaux, 2015. http://www.theses.fr/2015BORD0248/document.
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La première partie de cette thèse porte sur les automates cellulaires probabilistes (ACP) sur la ligne et à deux voisins. Pour un ACP donné, nous cherchons l'ensemble de ces lois invariantes. Pour des raisons expliquées en détail dans la thèse, ceci est à l'heure actuelle inenvisageable de toutes les obtenir et nous nous concentrons, dans cette thèse, surles lois invariantes markoviennes. Nous établissons, tout d'abord, un théorème de nature algébrique qui donne des conditions nécessaires et suffisantes pour qu'un ACP admette une ou plusieurs lois invariantes markoviennes dans le cas où l'alphabet E est fini. Par la suite, nous généralisons ce résultat au cas d'un alphabet E polonais après avoir clarifié les difficultés topologiques rencontrées. Enfin, nous calculons la fonction de corrélation du modèleà 8 sommets pour certaines valeurs des paramètres du modèle en utilisant une partie desrésultats précédentsThe first part of this thesis is about probabilistic cellular automata (PCA) on the line and with two neighbors. For a given PCA, we look for the set of its invariant distributions. Due to reasons explained in detail in this thesis, it is nowadays unthinkable to get all of them and we concentrate our reections on the invariant Markovian distributions. We establish, first, an algebraic theorem that gives a necessary and sufficient condition for a PCA to have one or more invariant Markovian distributions when the alphabet E is finite. Then, we generalize this result to the case of a polish alphabet E once we have clarified the encountered topological difficulties. Finally, we calculate the 8-vertex model's correlation function for some parameters values using previous results.The second part of this thesis is about infinite iterations of stochastic processes. We establish the convergence of the finite dimensional distributions of the α-stable processes iterated n times, when n goes to infinite, according to parameter of stability and to drift r. Then, we describe the limit distributions. In the iterated Brownian motion case, we show that the limit distributions are linked with iterated functions system
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Inácio, Ana Catarina Timóteo. "Modelo de avaliação de sustentabilidade de espaços verdes urbanos." Master's thesis, ISA/UL, 2014. http://hdl.handle.net/10400.5/8212.
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Mestrado em Arquitectura Paisagista - Instituto Superior de AgronomiaSustainability and sustainable development are among the most explored concepts of nowadays at all levels, political, financial, ecological, sociological, among others. The theoretical discussions around those concepts are leading to their exhaustion, requiring for objective methodologies that lead to the practice of those concepts. One of the most common ways to evaluate a system’s sustainability is through Indicators that quantify a specific reality. Urban green areas have a huge influence regarding the environmental, economic and social quality of a city therefore they have a fundamental role on urban sustainability. This thesis was prepared in this context, in order to quantify the sustainability of urban green areas through a sustainability evaluation model, using the method of indicators, and highlight their importance as an integral part of sustainable development, having not only a local impact but also a global one, using an experimental application in two distinct urban green area from the city of Torres Vedras, as a beginning of the study of its practical applicability
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Rasoloniaina, Alphonse. "Études expérimentales de dispositifs intégrés à base de micro-résonateurs à mode de galerie en verres actifs." Phd thesis, Université Rennes 1, 2014. http://tel.archives-ouvertes.fr/tel-01009345.
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Les microrésonateurs à mode de galerie passifs à base de cristal ou de verre fabriqués par la méthode de fusion possèdent un facteur de qualité limité à quelques 10E8. Ceci est généralement dû à la contamination de la surface du résonateur lors de sa fusion. Dans ces travaux, nous proposons de contourner cette limitation en utilisant des microrésonateurs actifs pour compenser les pertes. Afin de caractériser les microrésonateurs actifs de très haut facteur de qualité ainsi obtenu, nous nous appuyons sur la méthode CRDM (Cavity Ring Down Measurement). Cette méthode interférométrique est d'une part bien adaptée à la caractérisation de résonateurs de très haut facteur de qualité et d'autre part elle permet de remonter de manière univoque aux facteurs de qualité intrinsèque Qo et extrinsèque Qe du résonateur. Dans un régime de compensation de pertes, nous avons pu atteindre tous les régimes de couplage et obtenus des facteurs de qualité intrinsèques excédant les 10E10. En régime d'amplification sélective, nous avons démontré expérimentalement que l'on pouvait obtenir des gains élevés allant jusqu'à 33 dB et des retards de groupe excédant 2,3 µs dans ces microrésonateurs actifs. Ces microrésonateurs de très haut facteur de qualité et de très haute finesse peuvent présenter un couplage modal se manifestant par un doublet de résonances. Une confrontation théorie/expérience avec la méthode CRDM permet de mesurer un écart très faible entre les doublets. Par ailleurs, ces microrésonateurs présentant un fort confinement spatial et une forte surtension, sont propices à l'observation d'effets non-linéaires. Une modélisation intégrant l'effet thermique et l'effet Kerr a été réalisée. Une confrontation théorie/expérience nous a permis d'estimer la puissance réellement injectée dans le mode ainsi qu'à estimer le volume du mode.
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Mcgregor, Grant Duncan. "Calibration of the LHCb VELO detector and study of the decay mode D0->K-mu+nu_mu." Thesis, University of Manchester, 2011. https://www.research.manchester.ac.uk/portal/en/theses/calibration-of-the-lhcb-velo-detector-and-study-of-the-decay-mode-d0kmunumu(0c958072-451d-49b1-a6a0-a6e2683d087d).html.
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The LHCb experiment, based at the Large Hadron Collider at CERN, is primarily designed to make precision measurements of the decays of heavy flavour hadrons, such as B and D mesons. This thesis is composed of two parts: the first consists of two studies of LHCb's vertex locator (VELO) and the second describes the development of methods for recording the decay D0->K-mu+nu_mu. The first VELO study involves calibration and monitoring of the gain (i.e. the detector response to input charge from particles). We propose a robust method to measure the gain response of each silicon sensor using calibration bits output by the sensors, and a method to recalibrate the gain simple enough to be followed by non-expert VELO users. This is followed by an investigation into into the prospects of using the VELO to perform particle identification using the characteristic energy deposition of each particle species (dE/dx). Finally, studies into the development of a trigger and a so-called 'stripping line' for recording D0->K-mu+nu_mu decays is presented. The relatively high cross-section for charm decays in LHCb mean this decay (with a branching fraction of 3%) occurs frequently, and the challenge of a trigger is to reduce this to a rate acceptable to write to disk. Finally, based on a sample of data from July and August 2011, the measured q 2 distribution for this decay is compared to the simple single-pole theoretical model, and the pole mass is measured to bem_pole=2.35 + 0.81 - 0.35 GeV/c 2.
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Gentaz, Lucile. "Simulation et modélisation de l’altération des verres de composition médiévale dans l’atmosphère urbaine." Thesis, Paris Est, 2011. http://www.theses.fr/2011PEST1081.
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Dans un environnement urbain pollué, les altérations qui affectent les verres du patrimoine dépendent de facteurs intrinsèques, extrinsèques et temporels. Afin de caractériser les altérations atmosphériques résultant des interactions entre ces différents facteurs une stratégie de recherche prenant en compte un environnement multiphasique, le matériau (composition et surface) et le temps a été mise en place. Pour ce faire une étude complémentaire est menée sur des verres de vitraux exposés plusieurs centaines d'année et de verres modèles exposés en site réel et altéré artificiellement en laboratoire. Une approche multi-instrumentale et multi-échelle a été mise en place. Elle a permis d'identifier des mécanismes d'évolution de la couche d'altération (CA) notamment par la formation de lamines concentriques de ~10 nm (anciens fronts d'altération probables). L'exploration de l'impact des eaux de ruissellement montre que l'évolution de l'épaisseur de CA est dépendante à la fois d'une cinétique de diffusion (√t) et de dissolution (t). Enfin l'influence indirecte des produits néoformés sur l'altération semble jouer un rôle majeur à la fois en condition de ruissellement, avec la présence de CaCO3 qui précipite le détachement des écailles, et en milieu abrité, où la présence de K2CO3 est mise en cause dans la dissolution du réseau vitreuxIn a polluted urban environment, alterations affecting heritage glasses depend on intrinsic and extrinsic factors as well as time. In order to characterize the atmospheric alteration resulting from the interactions occurring between these factors, a research strategy has been set up, taking into account the multi-phase environment, the material (composition and surface) and time. In order to do so, a complementary study was conducted on stained glasses displaying several hundred years of alterations and model-glasses exposed in-situ for a few years or artificially altered in the lab. A multi-instrument and multi-scale approach was used in this study. It allowed the identification of the mechanisms responsible for the evolution of the leached layer (LL), especially the presence of concentric 10nm thick laminae (probable traces of alteration front). The exploration of the run-off impact on alteration shows a dependency of LL thickness on both diffusion type kinetics (√t) and dissolution kinetics. Finally, the indirect impact of neoformed alteration products seems to take a major part both in run-off conditions, CaCO3 hastens the scaling, and in sheltered conditions, where K2CO3 can be cause for glass network dissolution
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Ventura-Broncales, Carol-Cristina. "La educomunicación como un modelo para educar : el caso del proyecto fotográfico Pinhole Verte Mirarte." Bachelor's thesis, Universidad de Lima, 2016. http://repositorio.ulima.edu.pe/handle/ulima/2953.
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El presente artículo aspira dar a conocer los aportes educomunicativos del Proyecto Fotográfico Pinhole Verte MirArte, cuyo principal objetivo fue reconocer y despertar la mirada interna de niños, niñas y adolescentes de bajos recursos por medio del concepto y la práctica de la fotografía pinhole. Se trata de emplear la fotografía como una herramienta didáctica, la cual busca desarrollar la inteligencia racional y emotiva, así como el pensamiento crítico y la reflexión sobre la imagen. A través de un trabajo cualitativo, se consiguió evaluar los logros obtenidos en el desarrollo de competencias y análisis crítico de la realidad de los niños, niñas y adolescentes. Los resultados permiten reconocer la fotografía como una herramienta que genera más posibilidades de trabajar sobre los prejuicios de la persona que mira, dado que deja mucho más espacio a la imaginación. Por lo tanto, se construye una perspectiva hacia el desarrollo de habilidades narrativas en los beneficiarios a través de la creación de historias por medio de la fotografía, de esa manera ellos despiertan su capacidad crítica y reflexiva. Adicionalmente, la participación entre los beneficiaros sobre la base de objetivos comunes refuerza el trabajo colaborativo.Trabajos de investigación
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Paulin, Guillaume. "Transport électronique et Verres de Spins." Phd thesis, Ecole normale supérieure de lyon - ENS LYON, 2010. http://tel.archives-ouvertes.fr/tel-00556836.
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The results reported in this thesis contribute to the understanding of disordered systems, to mesoscopic physics on the one hand, and to the physics of spin glasses on the other hand. The first part of this thesis studies numerically coherent electronic transport in a non magnetic metal accurately doped with frozen magnetic impurities (a low temperature spin glass). Thanks to a recursive code that calculates the two terminal conductance of the system, we study in detail the metallic regime of conduction (large conductance) as well as the insulating regime (small conductance). In both regimes, we highlight a universal behavior of the system. Moreover, a study of correlations between the conductance of different spin configurations of impurities allows us to link these correlations with correlations between spin configurations. This study opens the route for the first experimental determination of the overlap via transport measurements. A second part of this thesis deals with the study of the mean field Sherrington-Kirkpatrick model, which describes the low temperature phase of an Ising spin glass. We are interested here in the generalization of this model to quantum spins (i.e including the possibility to flip by quantum tunneling) of this classical model that was well studied during the past thirty years. We deduce analytically motion equations at the semi-classical level, for which the influence of quantum tunneling is weak, and we compare them with the classical case. We finally solve numerically these equations using a pseudo-spectral method.
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Filali, Amine Ghali. "Dynamical reflection algebras and associated boundary integrable models." Thesis, Cergy-Pontoise, 2011. http://www.theses.fr/2011CERG0567/document.
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Cette thèse s’inscrit dans le cadre général de la théorie des systèmes intégrables avec bords et le développement des structures algébriques associées.D’une part, nous nous attaquons au problème de la diagonalisation de l’hamiltonien du modèle XXZ avec bords non diagonaux. Nous exhibons les deux ensembles d’états propres et valeurs propres du modèle si les paramètres de bords satisfont deux conditions.D’autre part, nous introduisons un modèle de physique statistique que nous appelons le modèle face avec un bord réfléchissant. Nous calculons exactement sa fonction de partition et nous montrons que cette dernière se représente simplement sous la forme d’un unique déterminant matriciel.Nous montrons que ces deux problèmes sont reliés par la transformation vertex-face et exhibent une structure algébrique commune, l’algèbre de réflexion dynamique. Nous nous intéressons aux aspects mathématiques de cette algèbre dans le cas elliptique général,et nous introduisons deux classes de ces représentations, la représentation de co-module d’évaluation et sa duale. Nous pensons que cette algèbre est la structure clef pour l’analyse des modèles faces avec bords. En particulier, nous montrons à l’aide de twists de Drinfel’d que leur fonction de partition se représente simplement dans le cas général. Enfin, nous tentons une ’dynamisation’ du modèle à vertex ’Half-Turn-Symmetric’,et nous décrivons sa fonction de partition en termes de représentation d’évaluation de l’algèbre de Yang-Baxter dynamique, et trouvons un ensemble de conditions la déterminantunivoquementThis thesis is embedded in the general theory of quantum integrable models withboundaries, and the development of associated algebraic structures.We first consider the question of the diagonalization of the XXZ hamiltonian with nondiagonalboundaries. We succeed to find the two sets of eigenstates and eigenvalues of themodel if the boundaries parameters satisfy two conditions.We introduce then a statistical physics model which we refer to be the face model witha reflecting end. Moreover, we compute exactly its partition function and show that it takesthe form of a simple single matrix determinant.We show that these two problems are related through the vertex-face transformationand are solved using a common algebraic structure, the dynamical reflection algebra andits dual. We focus from a mathematical perspective on this algebra in the general ellipticcase. Both the co-module evaluation representation and its dual are introduced. We believethat these structures are the key ingredients for the analysis of face models with boundaries.In particular, using the concept of Drinfel’d twists, we show that the partition function ofthese models has a simple representation in the general case.Finally, we attempt on a ’dynamization’ of the Half-Turn-Symmetric vertexmodel. Wedescribe its partition function in terms of the evaluation representation of the dynamicalYang-Baxter algebra, and find a set of conditions that uniquely determine it
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Watzky, Alexandre. "Sur la vibration non linéaire des fils précontraints (cordes, verges tendues)." Paris 6, 1992. http://www.theses.fr/1992PA066369.
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L'étude des vibrations des verges (ou des cordes) tendues est particulièrement riche par la multitude de phénomènes mis en jeu (non-linéarités, couplages de modes, amortissements. . . ). Partant d'une revue historique rappelant les diverses contributions depuis le traité de Rayleigh et permettant de préciser les phénomènes expliqués ainsi que les limites des modèles existants, on établit un modèle dynamique de verge plus général. Ce modèle non linéaire est construit à partir des équations locales de la mécanique des milieux continus, dans le cadre général des rotations et déplacements finis, son degré de finesse étant dicté par l'hypothèse des petites déformations. Cette approche, ici limitée au cas linéairement élastique, permet de placer l'étude dans un cadre mécanique à la fois précis et ouvert à d'autres relations de comportement (telles que thermoviscoélastique). L’utilisation d'une construction géométrique originale de la déformée de la ligne moyenne met immédiatement en évidence la torsion qui joue le rôle d'un paramètre. Ce phénomène, jusqu'ici éludé, peut alors être aisément pris en compte. Les conditions d'immobilité aux extrémités permettent de définir les modes spatiaux et d'aboutir, par projection sur ceux-ci des équations du mouvement, aux équations modales vérifiées par les parties temporelles de la solution. Ces équations, établies pour la première fois dans le cas le plus général, font clairement apparaître les divers couplages de modes et fournissent un outil apte à décrire la nature des mécanismes de couplage, certains étant soumis à des règles de sélection précises. Une étude de la génération de modes axiaux par les vibrations transversales permet d'expliquer les phénomènes constatés expérimentalement et met notamment en évidence la nécessaire combinaison de deux modes particuliers. On peut alors discuter la pertinence de la classique hypothèse d'allongement uniforme
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Tuchais, Simon. "Comment dire ce que « je » pense en japonais et en français : Étude contrastive de l’expression de l’opinion personnelle." Paris, EHESS, 2014. http://www.theses.fr/2014EHES0009.
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Cette étude a pour objectif de comprendre les moyens linguistiques mis en œuvre pour exprimer une opinion personnelle en japonais, en les confrontant avec leurs équivalents en français. La première partie s’attache à définir et décrire une classe d’expressions japonaises jouant un rôle de « modulateurs d’assertion » signalant l’expression d’une opinion personnelle, dont les caractéristiques, d’ordre syntaxique, sémantique, et énonciatif, sont mises en lumière par l’observation d’un emploi particulier du verbe omou (penser) régissant une séquence enchâssée par la particule to. À partir de l’expression prototypique to omou, on peut identifier divers modulateurs d’assertion formés à l’aide de trois types de variables : le verbe utilisé (kangaeru, kanjiru, ki ga suru), le type d’enchâssement (yô ni, ka to V, mono/koto to V), et l’emploi de la forme spontanée (omowareru / omoeru). La deuxième partie s’appuie sur ces résultats pour effectuer une étude contrastive, consistant tout d’abord à montrer – à travers l’analyse d’un corpus de traductions et l’examen des études sur les expressions ainsi mises au jour – qu’il est possible d’identifier en français également un ensemble cohérent de modulateurs d’assertion possédant des caractéristiques comparables (comprenant entre autres je crois, je pense, je trouve, il me semble. . . ), puis à examiner les catégories en jeu – personne, modalité, évidentialité – en prenant en compte leurs usages dans les traditions linguistiques japonaise et occidentale, avant d’effectuer une analyse contrastive des deux groupes d’expressions selon des paramètres modaux et évidentiels, qui permet de mettre en évidence l’organisation propre à chaque groupeThe goal of this study is to understand the linguistic means of expressing a personal opinion in Japanese, by comparing them with their French equivalents. The first part aims at defining and describing a class of Japanese expressions that play the role of “assertion modulator” indicating a personal opinion. The definition of this class is based on the observation of one particular use of the verb omou (think), with a clause embedded with the particle to. The prototypical expression to omou can be modified in three ways to produce various kinds of assertion modulators : changes may concern the verb (kangaeru, kanjiru, ki ga suru), the type of embedding of the clause (yô ni, ka to V, mono/koto to V), or the use of spontaneous forms (omowareru / omoeru). The second part is a contrastive study based on these results. As a first step, the analysis of a corpus of translations, and the examination of previous studies about the main French expressions used in this corpus, show that a set of assertion modulators that share some characteristics with their Japanese equivalents exists in French too (such as je crois, je pense, je trouve, il me semble. . . ). After a discussion about concepts involved, such as person, modality, and evidentiality, with regard to the different meaning they may have in Japanese and Western linguistics, a contrastive analysis of Japanese and French assertion modulators based on modal and evidential parameters reveals the particular organization of each group
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Pantel, Evelina [Verfasser]. "Valenz im ,Smysl-Tekst'-Modell : Eine konfrontative Analyse russischer und polnischer Verben / Evelina Pantel." Frankfurt a.M. : Peter Lang GmbH, Internationaler Verlag der Wissenschaften, 1993. http://d-nb.info/1165480506/34.
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ATASSI, HANAE. "Evaluation de la resistance a la corrosion en solution aqueuse de quelques verres silicates." Université Louis Pasteur (Strasbourg) (1971-2008), 1989. http://www.theses.fr/1989STR13057.
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Des experiences ont ete realisees afin d'evaluer la resistance chimique de verres volcaniques et industriels, mis en contact avec de l'eau distillee et des solutions tampons a ph 6, 7, 8 et 9. On a etudie au microscope electronique les couches d'alteration en surface et les resultats ont ete compares a un modele cinetique de la dissolution du verre ainsi qu'a un modele thermodynamique (modele de paul)
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Babenko, Constantin. "Fonctions à un point dans le modèle de sine-Gordon supersymétrique." Thesis, Sorbonne université, 2019. http://www.theses.fr/2019SORUS040.
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Cette thèse de doctorat traite le problème du calcul des fonctions à un point (1PF) dans les théories des champs quantiques bidimensionnelles intégrables. Une méthode pour leur calcul a été élaborée dans le contexte de la théorie de sine-Gordon. L'intégrabilité du modèle a été utilisée pour construire une base d'opérateurs locaux décrivant le modèle à six sommets. Cette base, appelée fermionique, est intéressante parce que les valeurs moyenne dans le vide de ses opérateurs sont exprimées en termes de déterminants et que la structure fermionique peut être étendue à la limite continue pour caractériser les opérateurs locaux dans la CFT. Dans cette thèse, nous poursuivons le travail sur cette approche, visant à généraliser la base fermionique au modèle de sine-Gordon supersymétrique (ssG). Nous avons dérivé des équations de scaling régissant la thermodynamique de la théorie ssG, reproduisant la fonction génératrice de BLZ. Ensuite, nous avons décrit la structure intégrable du modèle ssG grâce à la base fermion-courant. Nous nous sommes concentrés sur la partie fermionique et avons calculé ses fonctions à un point. Ces résultats ont été vérifiés avec une approche différente s'appuyant sur les relations de réflexionThis PhD thesis addresses the problem of the calculation of the one point functions (1PF) in integrable two-dimensional quantum field theories. A method for their calculation has been developed in the context of the sine-Gordon Theory. The integrability of the model was used to build a basis of local operators to describe the six-vertex model. This basis, called fermionic, is interesting because the vacuum expectation values of its operators are expressed in terms of determinants and the fermionic structure can be extended to the continuous limit in order to characterize local operators in the CFT. In this thesis, we continue to work on this approach, aiming to generalize the fermionic basis to the supersymmetric sine-Gordon model (ssG). We derived scaling equations governing the thermodynamics of the ssG theory, reproducing the BLZ generating function. Then, we described the integrable structure of the ssG model using the fermion-current basis. We focused on the fermionic part and calculated its one point functions. These results were verified with a different approach based on the reflection relations