Thèses : « Invariant cone »

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Bakit, Hany Albadrey Hosham [Verfasser], Tassilo [Akademischer Betreuer] Küpper et Rüdiger [Akademischer Betreuer] Seydel. « Cone-like Invariant Manifolds for Nonsmooth Systems / Hany Albadrey Hosham Bakit. Gutachter : Tassilo Küpper ; Rüdiger Seydel ». Köln : Universitäts- und Stadtbibliothek Köln, 2011. http://d-nb.info/1038065402/34.

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Fornasin, Nelvis [Verfasser], Sebastian [Akademischer Betreuer] Goette et Katrin [Akademischer Betreuer] Wendland. « [eta] invariants under degeneration to cone-edge singularities = η invariants under degeneration to cone-edge singularities ». Freiburg : Universität, 2019. http://d-nb.info/1203804326/34.

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Abdalla, Leonardo Batoni. « Propriedades eletrônicas dos isolantes topológicos ». Universidade de São Paulo, 2015. http://www.teses.usp.br/teses/disponiveis/43/43134/tde-17072015-140214/.

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Na busca de um melhor entendimento das propriedades eletrônicas e magnéticas dos isolantes topológicos nos deparamos com uma das suas caraterísticas mais marcantes, a existência de estados de superfície metálicos com textura helicoidal de spin os quais são protegidos de impurezas não magnéticas. Na superfície estes canais de spin possuem um potencial enorme para aplicações em dispositivos spintrônicos. Muito há para se fazer e o tratamento via cálculos de primeiros princípios por simulações permite um caráter preditivo que corrobora na elucidação de fenômenos físicos via análises experimentais. Nesse trabalho analisamos as propriedades eletrônicas de isolantes topológicos tais como: (Bi,Sb)$_2$(Te,Se)$_3$, Germaneno e Germaneno funcionalizado. Cálculos baseados em DFT evidenciam a importância das separações entre as camadas de Van der Waals nos materiais Bi$_2$Se$_3$ e Bi$_2$Te$_3$. Mostramos que devido a falhas de empilhamento, pequenas oscilações no eixo de QLs (\\textit{Quintuple Layers}) podem gerar um desacoplamento dos cones de Dirac, além de criar estados metálicos na fase \\textit{bulk} de Bi$_2$Te$_3$. Em se tratando do Bi$_2$Se$_3$ um estudo sistemático dos efeitos de impurezas de metais de transição foi realizado. Observamos que há quebra de degenerescência do cone de Dirac se houver magnetização em quaisquer dos eixos. Além disso se a magnetização permanecer no plano, além de uma pequena quebra de degenerescência, há um deslocamento do mesmo para outro ponto da rede recíproca. No entanto, se a magnetização apontar para fora do plano a quebra ocorre no próprio ponto $\\Gamma$, porém de maneira mais intensa. Importante enfatizar que além de mapear os sítios com suas orientações magnéticas de menor energia observamos que a quebra da degenerescência está diretamente relacionada com a geometria local da impureza. Isso proporciona imagens de STM distintas para cada sítio possível, permitindo que um experimental localize cada situação no laboratório. Estudamos ainda a transição topológica na liga (Bi$_x$Sb$_{1-x}$)$_2$Se$_3$, onde identificamos um isolante trivial e topológico para $x=0$ e $x=1$. Apesar de óbvia a existência de tal transição, detalhes importantes ainda não estão esclarecidos. Concluímos que a dopagem com impurezas não magnéticas proporciona uma boa técnica para manipulação e engenharia de cone nesta família de materiais, de forma que dependendo da faixa de dopagem podemos eliminar a condutividade que advém do \\textit{bulk}. Finalmente estudamos superfícies de Germaneno e Germaneno funcionalizado com halogênios. Usando uma funcionalização assimétrica e com a avalição do invariante topológico $Z_2$ notamos que o material Ge-I-H é um isolante topológico podendo ser aplicado na elaboração de dispositivos baseados em spin.
In the search of a better understanding of the electronic and magnetic properties of topological insulators we are faced with one of its most striking features, the existence of metallic surface states with helical spin texture which are protected from non-magnetic impurities. On the surface these spin channels allows a huge potential for applications in spintronic devices. There is much to do and treating calculations via \\textit{Ab initio} simulations allows us a predictive character that corroborates the elucidation of physical phenomena through experimental analysis. In this work we analyze the electronic properties of topological insulators such as: (Bi, Sb)$_2$(Te, Se)$_3$, Germanene and functionalized Germanene. Calculations based on DFT show the importance of the separation from interlayers of Van der Waals in materials like Bi$_2$Se$_3$ and Bi$_2$Te$_3$. We show that due to stacking faults, small oscillations in the QLs axis (\\textit{Quintuple Layers}) can generate a decoupling of the Dirac cones and create metal states in the bulk phase Bi$_2$Te$_3$. Regarding the Bi$_2$Se$_3$ a systematic study of the effects of transition metal impurities was performed. We observed that there is a degeneracy lift of the Dirac cone if there is any magnetization on any axis. If the magnetization remains in plane, we observe a small shift to another reciprocal lattice point. However, if the magnetization is pointing out of the plane a lifting in energy occurs at the very $ \\Gamma $ point, but in a more intense way. It is important to emphasize that in addition to mapping the sites with their magnetic orientations of lower energy we saw that the lifting in energy is directly related to the local geometry of the impurity. This provides distinct STM images for each possible site, allowing an experimental to locate each situation in the laboratory. We also studied the topological transition in the alloy (Bi$_x$Sb$_{1-x}$)$_ 2$Se$_3$, where we identify a trivial and topological insulator for $x = 0$ and $x = 1$. Despite the obvious existence of such a transition, important details remain unclear. We conclude that doping with non-magnetic impurities provides a good technique for handling and cone engineering this family of materials so that depending on the range of doping we can eliminate conductivity channels coming from the bulk. Finally we studied a Germanene and functionalized Germanene with halogens. Using an asymmetrical functionalization and with the topological invariant $Z_2$ we noted that the Ge-I-H system is a topological insulator that could be applied in the development of spin-based devices.

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Yasamin, A. S. « Maximal invariants over symmetric cones ». [Bloomington, Ind.] : Indiana University, 2008. http://gateway.proquest.com/openurl?url_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&res_dat=xri:pqdiss&rft_dat=xri:pqdiss:3337265.

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Thesis (Ph.D.)--Indiana University, Dept. of Mathematics, 2008.
Title from PDF t.p. (viewed on Jul 28, 2009). Source: Dissertation Abstracts International, Volume: 69-12, Section: B, page: 7597. Adviser: Steen Andersson.

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Kapanadze, David, Bert-Wolfgang Schulze et Ingo Witt. « Coordinate invariance of the cone algebra with asymptotics ». Universität Potsdam, 2000. http://opus.kobv.de/ubp/volltexte/2008/2567/.

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The cone algebra with discrete asymptotics on a manifold with conical singularities is shown to be invariant under natural coordinate changes, where the symbol structure (i.e., the Fuchsian interior symbol, conormal symbols of all orders) follows a corresponding transformation rule.

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Rossi, Marco. « Dynamics and stability of discrete and continuous structures : flutter instability in piecewise-smooth mechanical systems and cloaking for wave propagation in Kirchhoff plates ». Doctoral thesis, Università degli studi di Trento, 2021. http://hdl.handle.net/11572/322240.

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The first part of this Thesis deals with the analysis of piecewise-smooth mechanical systems and the definition of special stability criteria in presence of non-conservative follower forces. To illustrate the peculiar stability properties of this kind of dynamical system, a reference 2 d.o.f. structure has been considered, composed of a rigid bar, with one and constrained to slide, without friction, along a curved profile, whereas the other and is subject to a follower force. In particular, the curved constraint is assumed to be composed of two circular profiles, with different and opposite curvatures, defining two separated subsystems. Due to this jump in the curvature, located at the junction point between the curved profiles, the entire mechanical structure can be modelled by discontinuous equations of motion, the differential equations valid in each subsystem can be combined, leading to the definition of a piecewise-smooth dynamical system. When a follower force acts on the structure, an unexpected and counterintuitive behaviour may occur: although the two subsystems are stable when analysed separately, the composed structure is unstable and exhibits flutter-like exponentially-growing oscillations. This special form of instability, previously known only from a mathematical point of view, has been analysed in depth from an engineering perspective, thus finding a mechanical interpretation based on the concept of non-conservative follower load. Moreover, the goal of this work is also the definition of some stability criteria that may help the design of these mechanical piecewise-smooth systems, since classical theorems cannot be used for the investigation of equilibrium configurations located at the discontinuity. In the literature, this unusual behaviour has been explained, from a mathematical perspective, through the existence of a discontinuous invariant cone in the phase space. For this reason, starting from the mechanical system described above, the existence of invariant cones in 2 d.o.f. mechanical systems is investigated through Poincaré maps. A complete theoretical analysis on piecewise-smooth dynamical systems is presented and special mathematical properties have been discovered, valid for generic 2~d.o.f. piecewise-smooth mechanical systems, which are useful for the characterisation of the stability of the equilibrium configurations. Numerical tools are implemented for the analysis of a 2~d.o.f. piecewise-smooth mechanical system, valid for piecewise-linear cases and extendible to the nonlinear ones. A numerical code has been developed, with the aim of predicting the stability of a piecewise-linear dynamical system a priori, varying the mechanical parameters. Moreover, “design maps” are produced for a given subset of the parameters space, so that a system with a desired stable or unstable behaviour can easily be designed. The aforementioned results can find applications in soft actuation or energy harvesting. In particular, in systems devoted to exploiting the flutter-like instability, the range of design parameters can be extended by using piecewise-smooth instead of smooth structures, since unstable flutter-like behaviour is possible also when each subsystem is actually stable. The second part of this Thesis deals with the numerical analysis of an elastic cloak for transient flexural waves in Kirchhoff-Love plates and the design of special metamaterials for this goal. In the literature, relevant applications of transformation elastodynamics have revealed that flexural waves in thin elastic plates can be diverted and channelled, with the aim of shielding a given region of the ambient space. However, the theoretical transformations which define the elastic properties of this “invisibility cloak” lead to the presence of a strong compressive prestress, which may be unfeasible for real applications. Moreover, this theoretical cloak must present, at the same time, high bending stiffness and a null twisting rigidity. In this Thesis, an orthotropic meta-structural plate is proposed as an approximated elastic cloak and the presence of the prestress has been neglected in order to be closer to a realistic design. With the aim of estimating the performance of this approximated cloak, a Finite Element code is implemented, based on a sub-parametric technique. The tool allows the investigation of the sensitivity of specific stiffness parameters that may be difficult to match in a real cloak design. Moreover, the Finite Element code is extended to investigate a meta-plate interacting with a Winkler foundation, to analyse how the substrate modulus transforms in the cloak region. This second topic of the Thesis may find applications in the realization of approximated invisibility cloaks, which can be employed to reduce the destructive effects of earthquakes on civil structures or to shield mechanical components from unwanted vibrations.

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Jorge, Guilherme Henrique Renó. « Arquitetura para extração de características invariantes em imagens binárias utilizando dispositivos de lógica programável complexa ». Universidade de São Paulo, 2006. http://www.teses.usp.br/teses/disponiveis/18/18133/tde-06022007-141241/.

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Os projetistas de sistemas digitais enfrentam sempre o desafio de encontrar o balanço correto entre velocidade e generalidade de processamento de seu hardware. Originalmente dispositivos de lógica programável de alta densidade como FPGAs (Field Programable Gate Arrays) e CPLDs (Complex Logic Programmable Devices) vinham sendo utilizados como dispositivos de lógica acoplada(glue logic), reduzindo significantemente o número de componentes em um sistema. Seu uso como forma de substituir arquiteturas já existentes de microcontroladores e microprocessadores já é uma realidade. A representação e reconhecimento de objetos em imagens de duas dimensões é um tópico importante. Uma forma comum de se fazer a representação de um objeto ou uma imagem é a utilização de momentos da função de intensidade de um grupo de pixels. Devido ao alto custo computacional para o cálculo desses momentos tem sido importante a busca por arquiteturas que de alguma forma agilizem o cálculo dos mesmos. Um problema enfrentado por arquiteturas desenvolvidas atualmente para trabalhar em forma de periférico com um computador pessoal (PC) ou uma estação de trabalho é a velocidade do barramento de transferência de dados. Interfaces de uso mais simples, como USB (Universal Serial Bus) ou Ethernet, têm sua taxa de transferência na casa dos megabytes por segundo. Uma solução para esse problema é o uso do barramento PCI, as transferências feitas nesse barramento podem chegar à casa dos gigabytes por segundo. Esse trabalho vem apresentar uma arquitetura, em forma de soft core totalmente compatível com o padrão Wishbone, para a extração de características invariantes em imagens binárias utilizando-se de dispositivos de lógica programável complexa. Desse modo torna-se possível o uso do barramento PCI para a transmissão de dados para um microcomputador ou uma estação de trabalho.
A challenge for digital systems designers is to meet the balance between speed and flexibility was always. FPGAs and CPLDs where used as glue logic, reducing the number of components in a system. The use of programmable logic (CPLDs and FPGAs) as an alternative to microcontrollers and microprocessors is a real issue. Moments of the intensity function of a group of pixels have been used for the representation and recognition of objects in two dimensional images. Due to the high cost of computing the moments, the search for faster computing architectures is very important. A problem faced by nowadays developed architectures is the speed of computer communication buses. Simpler interfaces, as USB (Universal Serial Bus) and Ethernet, have their transfer rate in megabytes per second. A solution for this problem is the use the PCI bus, where the transfer rate can achieve gigabytes per second. This work presents a soft core architecture, fully compatible with the Wishbone standard, for the extraction of invariant characteristics from binary images using logic programmable devices.

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Riley, Timothy Rupert. « Asymptotic invariants of infinite discrete groups ». Thesis, University of Oxford, 2002. http://ora.ox.ac.uk/objects/uuid:30f42f4c-e592-44c2-9954-7d9e8c1f3d13.

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Asymptotic cones. A finitely generated group has a word metric, which one can scale and thereby view the group from increasingly distant vantage points. The group coalesces to an "asymptotic cone" in the limit (this is made precise using techniques of non-standard analysis). The reward is that in place of the discrete group one has a continuous object "that is amenable to attack by geometric (e.g. topological, infinitesimal) machinery" (to quote Gromov). We give coarse geometric conditions for a metric space X to have N-connected asymptotic cones. These conditions are expressed in terms of certain filling functions concerning filling N-spheres in an appropriately coarse sense. We interpret the criteria in the case where X is a finitely generated group Γ with a word metric. This leads to upper bounds on filling functions for groups with simply connected cones -- in particular they have linearly bounded filling length functions. We prove that if all the asymptotic cones of Γ are N-connected then Γ is of type F_N+1 and we provide N-th order isoperimetric and isodiametric functions. Also we show that the asymptotic cones of a virtually polycyclic group Γ are all contractible if and only if Γ is virtually nilpotent. Combable groups and almost-convex groups. A combing of a finitely generated group Γ is a normal form; that is a choice of word (a combing line) for each group element that satisfies a geometric constraint: nearby group elements have combing lines that fellow travel. An almost-convexity condition concerns the geometry of closed balls in the Cayley graph for Γ. We show that even the most mild combability or almost-convexity restrictions on a finitely presented group already force surprisingly strong constraints on the geometry of its word problem. In both cases we obtain an n! isoperimetric function, and upper bounds of ~ n² on both the minimal isodiametric function and the filling length function.

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SILVA, Thársis Souza. « Equações Diferenciais por partes:ciclos limite e cones invaiantes ». Universidade Federal de Goiás, 2011. http://repositorio.bc.ufg.br/tede/handle/tde/1945.

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Made available in DSpace on 2014-07-29T16:02:18Z (GMT). No. of bitstreams: 1 Dissertacao Tharsis Souza Silva.pdf: 1389814 bytes, checksum: c28dfe55ac776a4de30d43875907dc64 (MD5) Previous issue date: 2011-03-25
In this work, we consider classes of discontinuous piecewise linear systems in the plane and continuous in the space. In the plane, we analyze systems of focus-focus (FF), focusparabolic (FP) and parabolic-parabolic (PP) type, separated by the straight line x = 0, and we prove that can appear until two limit cycles depending of parameters variations. Also we study a specific system, piecewise, with two saddles (one fixed in the origin and the other in the neighborhood of point (1;1)) separated by the straight line y= -x+1, and we show that can appear until two limit cycles depending of parameters variations. Finally, we examine a continuous piecewise linear system in R³ and we prove the existence of invariant cones and, through this structures, we determine some stable and unstable behavior.
Neste trabalho, consideramos classes de sistemas lineares por partes descontínuos no plano e contínuos no espaço. No plano, analisamos sistemas do tipo foco-foco (FF), parabólico-foco (PF) e parabólico-parabólico (PP) separados pela reta x = 0 e demonstramos que podem aparecer até dois ciclos limite, dependendo de variações de parâmetros. Também estudamos um sistema específico, linear por partes, com duas selas (uma sela fixa na origem e outra na vizinhança do ponto (1;1)) separadas pela reta y= -x+1 , e mostramos que podem aparecer até dois ciclos limite dependendo de variações de parâmetros. Por fim, examinamos um sistema linear por partes contínuo em R³ e demonstramos a existência de cones invariantes e, através destas estruturas, determinamos alguns comportamentos estáveis e instáveis.

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Constantin, Elena. « Optimization and flow invariance via high order tangent cones ». Ohio : Ohio University, 2005. http://www.ohiolink.edu/etd/view.cgi?ohiou1125418579.

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MOTA, Marcos Coutinho. « Cones Invariantes em Sistemas Lineares por Partes Contínuos em ℝ³ ». reponame:Repositório Institucional da UNIFEI, 2016. http://repositorio.unifei.edu.br:8080/xmlui/handle/123456789/645.

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Apresentamos um estudo sobre cones invariantes em sistemas lineares por partes contínuos e observáveis em ℝ³. Utilizando uma forma paramétrica, estabelecemos a aplicação de Poincaré P, essencial para o estudo da estabilidade da origem e também da existência, unicidade e estabilidade de cones invariantes de duas zonas. Mostramos que a estabilidade da origem está bem definida quando o sistema estudado não possui cones invariantes de duas zonas e apresentamos um exemplo não intuitivo de um sistema linear por partes contínuo no qual as matrizes que definem os sistemas lineares envolvidos são Hurwitzianas, mas a origem é um ponto de equilíbrio instável.

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Patraucean, Viorica. « Detection and identification of elliptical structure arrangements in images : theory and algorithms ». Thesis, Toulouse, INPT, 2012. http://www.theses.fr/2012INPT0020/document.

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Cette thèse porte sur différentes problématiques liées à la détection, l'ajustement et l'identification de structures elliptiques en images. Nous plaçons la détection de primitives géométriques dans le cadre statistique des méthodes a contrario afin d'obtenir un détecteur de segments de droites et d'arcs circulaires/elliptiques sans paramètres et capable de contrôler le nombre de fausses détections. Pour améliorer la précision des primitives détectées, une technique analytique simple d'ajustement de coniques est proposée ; elle combine la distance algébrique et l'orientation du gradient. L'identification d'une configuration de cercles coplanaires en images par une signature discriminante demande normalement la rectification Euclidienne du plan contenant les cercles. Nous proposons une technique efficace de calcul de la signature qui s'affranchit de l'étape de rectification ; elle est fondée exclusivement sur des propriétés invariantes du plan projectif, devenant elle même projectivement invariante
This thesis deals with different aspects concerning the detection, fitting, and identification of elliptical features in digital images. We put the geometric feature detection in the a contrario statistical framework in order to obtain a combined parameter-free line segment, circular/elliptical arc detector, which controls the number of false detections. To improve the accuracy of the detected features, especially in cases of occluded circles/ellipses, a simple closed-form technique for conic fitting is introduced, which merges efficiently the algebraic distance with the gradient orientation. Identifying a configuration of coplanar circles in images through a discriminant signature usually requires the Euclidean reconstruction of the plane containing the circles. We propose an efficient signature computation method that bypasses the Euclidean reconstruction; it relies exclusively on invariant properties of the projective plane, being thus itself invariant under perspective

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FERREIRA, Liliane da Cunha. « Órbitas Periódicas e Cones Invariantes em Sistemas Lineares por Partes Contínuos em ℝ³ ». reponame:Repositório Institucional da UNIFEI, 2018. http://repositorio.unifei.edu.br/xmlui/handle/123456789/1194.

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Apresentamos um estudo sobre a existência de cones invariantes em uma família de sistemas lineares por partes contínuos e não observáveis em ℝ³. Inicialmente, encontramos uma subfamília de tais sistemas que apresenta um único cone invariante folheado por órbitas periódicas. Depois disto, perturbamos os membros da subfamília, através de uma perturbação linear, tornando-os observáveis e não homogêneos e, então, estudamos as órbitas periódicas que persistem as quais estão associadas com os zeros de uma função integral.

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Bouillot, Olivier. « Invariants analytiques des diffeomorphismes et multizetas ». Phd thesis, Université Paris Sud - Paris XI, 2011. http://tel.archives-ouvertes.fr/tel-00647909.

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Ce travail comprends deux parties indépendantes, mais intimement liées. La première partie concerne le calcul et l'évaluation numérique des invariants holomorphes des difféomorphismes tangents à l'identité, dans le cas-type. On y expose notamment trois méthodes de calculs numériques, dont l'une est basée sur une formule explicite des invariants. Celle-ci résulte de l'évaluation de l'application de cornes 7[+, dont les ingrédients de base sont des rationnels, des coefficients de Taylor du difféomorphisme étudié et des multitangentes. La seconde partie concerne l'étude des multitangentes et des relations les liant entre elles. Il s'agit de fonctions I-périodiques, généralisant les séries d'Eisenstein, et définissant un moule symétr~l. D'autres relations existent, tels la réduction en monotangentes qui indique un lien profond entre les multitangentes et les multizêtas. Des propriétés et conjectures de nature purement algébrique, arithmétique ou analytique sont ensuite exposées.

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Melo, Rodrigo Fernandes de Moura. « Hipersuperfícies em Rp+q+2 de curvatura escalar nula invariantes por O(p+1) x O(q+1) ». Universidade Federal de Alagoas, 2009. http://repositorio.ufal.br/handle/riufal/1030.

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This dissertation has as base Jocelino Sato and Vicente de Souza Neto's paper called Complete and Stable O(p + 1) x O(q + 1)-Invariant Hypersurfaces with Zero Scalar Curvature in Euclidean Space Rp+q+2, published on the Annals of Global Analysis and Geometry - 29 in 2006. The main result of this dissertation is the Classi_cation Theorem, which states: The O(p+1) x O(q+1)-Invariant Hypersurfaces in Rp+q+2, p; q > 1, with zero scalar curvature belong to one of the following classes: (1) Cones with a singularity at the orign of Rp+q+2; (2) Hypersurfaces having one orbit of singularity and asymptoting both of the cones Cα and Cβ; (3) Regular hypersurfaces asymptoting the cone Cα; (4) Regular hypersurfaces asymptoting the cone Cβ; (5) Regular hypersurfaces asymptoting both of the cones Cα and Cβ. It was reached by the studies of the ordinary differential equation on R2, involving the coordenate curves that generate these hypersurfaces. Such differential equation, in its turn, is associated with a vector field X : R22 → R2 on the plan. The study of the orbits space in this field is essential; after all, because of it, it was possible to translate the X orbits' behavior into information concerning the profile curves and, finally, reach the theorem.
Fundação de Amparo a Pesquisa do Estado de Alagoas
Esta dissertação está baseada no artigo de Jocelino Sato e Vicente de Souza Neto intitulado Complete and Stable O(p+1) x O(q+1) - Invariant Hypersurfaces with Zero Scalar Curvature in Euclidean Space Rp+q+2, publicado na revista Annals of Global Analysis and Geometry, volume 29, em 2006. O principal resultado desta dissertação é o Teorema de Classicação, que afirma o seguinte: Uma hipersuperfície Mp+q+1 que é invariante pela açãoao do grupo O(p + 1) x O(q + 1), p; q > 1, com curvatura escalar identicamente nula deve pertencer a uma das seguintes classes: (1) Cones com uma singularidade na origem de Rp+q+2; (2) Hipersuperfícies possuindo uma órbita de singularidades e assintotando ambos os cones Cα e Cβ; (3) Hipersuperfícies regulares que assintotam o cone Cα; (4) Hipersuperfícies regulares que assintotam o cone Cβ; (5) Hipersuperfícies regulares que assintotam ambos os cones Cα e Cβ. A demonstração do teorema requer um estudo de uma equação diferencial ordinária envolvendo as coordenadas das curvas, no plano, que geram estas hipersuperfícies. Esta equação diferencial, por sua vez, está associada a um campo de vetores X : R2 → R2 no plano. O estudo do retrato de fase deste campo é fundamental. Através dele, foi possível traduzir o comportamento das trajetórias de X em informações com respeito às curvas geratrizes e desta maneira obter o teorema.

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Bouillot, Olivier. « Invariants analytiques des difféomorphismes et multizêtas ». Thesis, Paris 11, 2011. http://www.theses.fr/2011PA112224/document.

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Ce travail comprends deux parties indépendantes, mais intimement liées. La première partie concerne le calcul et l'évaluation numérique des invariants holomorphes des difféomorphismes tangents à l'identité, dans le cas-type. On y expose notamment trois méthodes de calculs numériques, dont l'une est basée sur une formule explicite des invariants. Celle-ci résulte de l'évaluation de l'application de cornes 7[+, dont les ingrédients de base sont des rationnels, des coefficients de Taylor du difféomorphisme étudié et des multitangentes. La seconde partie concerne l'étude des multitangentes et des relations les liant entre elles. Il s'agit de fonctions I-périodiques, généralisant les séries d'Eisenstein, et définissant un moule symétr~l. D'autres relations existent, tels la réduction en monotangentes qui indique un lien profond entre les multitangentes et les multizêtas. Des propriétés et conjectures de nature purement algébrique, arithmétique ou analytique sont ensuite exposées
This work contains two independant parts, witch are deeply very closed. The first part deals with the calculation and the numerical evaluation of the holomor¬phic invariants of tangent to identity diffeomorphisms, in the type-case. ln particular, we display here three methods of numerical computation whose the last is based on an ex¬plicit formula of invariants. These result of calculation of the horn map 7[+, whose basics components are sorne rationnaIs, sorne Taylor coefficients of the diffeomorphism which is studied and multitangents. The second part deals with a général study of multitangents and relations between them. They are I-periodic functions, generalizing Eisenstein series and defining a symetr~l mould. There are others relations, like the reduction into monotangents which point out to us a profound link between multitangents and multiz~tas values. Properties and conjec¬tures of purely algebraic, arithmetical or analytical kirig are then explain

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Mohsen, Omar. « Deformation groupoids and applications ». Thesis, Sorbonne Paris Cité, 2018. http://www.theses.fr/2018USPCC200/document.

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Cette thèse est consacrée à l’étude de trois questions différentes concernant les groupoïdes de Lie et leurs applications. Le premier chapitre présente quelques préliminaires sur les groupoïdes de Lie. Dans le chapitre 2, on exprime la déformation de Witten à l’aide d’une déformation au cone normal et la théorie de C∗-modules ce qui nous permet de retrouver les inégalités de Morse. Notre méthode se généralise au cas des feuilletages. Dans le chapitre 3, on donne une construction simple du groupoïde de déformation construit par Choi-Pönge et Van Erp-Yuncken. Rappelons que celui-ci décrit le calcule pseudo-différentiel inhomogène grâce au travail de Debord-Skandalis et Van Erp- Yuncken. Notre construction montre que le groupoïde de déformation est en fait une déformation au cone normal classique itérée. Dans le chapitre 4, suivant le travail de Antonini, Azzali et Skandalis, on construit un élément en KK-théorie équivariante qui permet d’exprimer directement les invariants de Chern-Simons en K-théorie. Dans l’appendice on donne quelques rappels sur la KK-théorie équivariante et la KK-théorie réelle introduite par Antonini, Azzali et Skandalis
This thesis is devoted to the study of three different questions concerning Lie groupoids and their applications. The first chapter presents some preliminaries on Lie groupoids. In Chapter 2, Witten’s deformation is expressed using deformation to the normal cone construction and the theory of C∗-modules, which allows us to reprove the Morse inequalities. Our method is generalised to the case of foliations. In Chapter 3, we give a simple construction of the deformation groupoid built by Choi-Pönge and Van Erp-Yuncken. Recall that this groupoid describes the inhomogeneous pseudo-differential calculus thanks to the work of Debord-Skandalis and Van Erp-Yuncken. Our construction shows that the deformation groupoid is actually an iterated classical deformation to the normal cone. In Chapter 4, following the work of Antonini, Azzali and Skandalis, we construct an element in equivariant KK-theory that allows us to express the Chern-Simons invariants directly in K-theory. In the appendix we give some reminders about the equivariant KK-theory and the real KK-theory introduced by Antonini, Azzali and Skandalis

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Boni, Keila Tatiana. « Invariantes operatórios e níveis de generalidade manifestados por estudantes dos anos iniciais do ensino fundamental em tarefas não-rotineiras ». Universidade Estadual de Londrina. Centro de Ciências Exatas. Programa de Pós-Graduação em Ensino de Ciências e Educação Matemática, 2014. http://www.bibliotecadigital.uel.br/document/?code=vtls000198985.

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A presente pesquisa tem como objetivo investigar em tarefas matemáticas não-rotineiras as manifestações de invariantes operatórios e níveis de generalidade manifestados por seis estudantes do 5º ano do Ensino Fundamental de uma escola Municipal de Apucarana PR em procedimentos de cálculo. Para tanto, utilizamos estudos relacionados a procedimentos de cálculo, pensamento aritmético e pensamento algébrico, e elementos das teorias dos Campos Conceituais e de Níveis de Generalidade para a análise das informações. Tais informações, as quais foram coletadas por meio de gravações em áudio, registros escritos e diários de campo, foram submetidas a procedimentos analíticos à luz da Análise Textual Discursiva. Concluímos que os estudantes participantes da pesquisa se encontravam em um nível de transição entre generalidade aritmética e generalidade algébrica factual. Tal conclusão foi pautada a partir das manifestações dos estudantes, sobretudo em linguagem natural expressa oralmente, em que fica evidente a percepção de características invariantes relacionadas aos procedimentos de cálculo que, devido à maneira e frequência com que foram utilizadas, as instituímos como invariantes operatórios do tipo teoremas-em-ação.
This research aims to investigate in non-routine mathematical tasks, operatory invariants and levels of generality expressed by six students of the 5th year of elementary school in a Municipal School in Apucarana - PR in calculation procedures. Therefore, we use the related calculation procedures, arithmetic thinking and algebraic thinking, theories and elements of the Conceptual Fields and Levels of Generality for information analysis studies. These data, which were collected through audio recordings, written registers and daily field, were subjected to analytical procedures in the light of Textual Analysis Discursive. We conclude that students participating in the research were at a level of transition between arithmetic generality and algebraic generality factual. This conclusion was based from the manifestations of students, mainly expressed in natural language orally, in which the perception of invariant characteristics related to the calculation procedures is evident that due to the manner and frequency with which they were used, as instituted operatory invariants of type theorems-in-action.

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Harding, Andrew. « Uniqueness of g-measures and the invariance of the beta-function under finitary isomorphisms, with finite expected code lengths, between g-spaces ». Thesis, University of Warwick, 1985. http://wrap.warwick.ac.uk/89143/.

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The following is split into two chapters. The first chapter gives a brief history concerning g-measures, their state of investigation and under what conditions, on g, unique g-measures exist. It concludes by giving equivalent conditions for a g-function to have a unique g-measure. This will, possibly, lead to a solution to Keane’s original problem about the uniqueness of a g-measure for an arbitrary g-function. The second chapter generalises the result of Prof. K. Schmidt that the Beta-function is invariant under finitarily isomorphic (with finite expected code length) Markov spaces, to g-spaces with certain conditions on the g-function. The approach adopted is essentially that of Schmidt with slight modifications due to the more restrictive nature of the problem. The condition on the g-function, that of finite first moment variational sum, fits nicely between the two more commonly used conditions, finite variation sum and exponentially decreasing variation.

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Franceschi, Sandro. « Approche analytique pour le mouvement brownien réfléchi dans des cônes ». Thesis, Tours, 2017. http://www.theses.fr/2017TOUR4046/document.

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Le mouvement Brownien réfléchi de manière oblique dans le quadrant, introduit par Harrison, Reiman, Varadhan et Williams dans les années 80, est un objet largement analysé dans la littérature probabiliste. Cette thèse, qui présente l’étude complète de la mesure invariante de ce processus dans tous les cônes du plan, a pour objectif plus global d’étendre au cadre continu une méthode analytique développée initialement pour les marches aléatoires dans le quart de plan par Fayolle, Iasnogorodski et Malyshev dans les années 70. Cette approche est basée sur des équations fonctionnelles, reliant des fonctions génératrices dans le cas discret et des transformées de Laplace dans le cas continu. Ces équations permettent de déterminer et de résoudre des problèmes frontière satisfaits par ces fonctions génératrices. Dans le cas récurrent, cela permet de calculer explicitement la mesure invariante du processus avec rebonds orthogonaux, dans le chapitre 2, et avec rebonds quelconques, dans le chapitre 3. Les transformées de Laplace des mesures invariantes sont prolongées analytiquement sur une surface de Riemann induite par le noyau de l’équation fonctionnelle. L’étude des singularités et l’application de méthodes du point col sur cette surface permettent de déterminer l’asymptotique complète de la mesure invariante selon toutes les directions dans le chapitre 4
Obliquely reflected Brownian motion in the quadrant, introduced by Harrison, Reiman, Varadhan and Williams in the eighties, has been studied a lot in the probabilistic literature. This thesis, which presents the complete study of the invariant measure of this process in all the cones of the plan, has for overall aim to extend to the continuous framework an analytic method initially developped for random walks in the quarter plane by Fayolle, Iasnogorodski and Malyshev in the seventies. This approach is based on functional equations which link generating functions in the discrete case and Laplace transform in the continuous case. These equations allow to determine and to solve boundary value problems satisfied by these generating functions. In the recurrent case, it permits to compute explicitly the invariant measure of the process with orthogonal reflexions, in the chapter 2, and with any reflexions, in the chapter 3. The Laplace transform of the invariant measure is analytically extended to a Riemann surface induced by the kernel of the functional equation. The study of singularities and the use of saddle point methods on this surface allows to determine the full asymptotics of the invariant measure along every directions in the chapter 4

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Hanna, Mirna. « Une approche sémiotique de l’architecture domestique à Beyrouth au XXème siècle. Étude comparative de deux cas typologiques ». Thesis, Paris 4, 2011. http://www.theses.fr/2011PA040076.

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L’analyse sémiotique de l’architecture domestique a pour but de voir comment se manifestent, à travers le langage architectural, les comportements codés qui remplacent la communication linguistique, en postulant qu'il y a un déterminisme de l'architecture par les valeurs macro-sociales, et que le signe architectural doit être considéré comme un marqueur anthropologique. L’approche pluridisciplinaire qui allie des champs aussi divers que l’architecture, la sémiologie et l’anthropologie, a pour ambition de contribuer d’une part, à la sémiotique de l’architecture en proposant une méthodologie pour l’analyse et le découpage d’un corpus architectural, et d’une autre, d’élargir le champ de la géographie urbaine à de nouvelles disciplines, et enfin, de proposer une lecture inédite du paysage urbain à Beyrouth à travers l’étude comparative de deux typologies architecturales. L’approche sémiotique proposée peut être appliquée en tant qu’outil de la géographie urbaine à des corpus architecturaux ou des pans du tissu urbain afin d’appréhender les mécanismes de production et d’obsolescence des formes, et par extension de la ville
The purpose of a semiotic analysis of architecture is to see how non verbal codes manifest themselves through the architectural language, based upon the idea that such a language is conditioned by macro-social values, and therefore the architectural sign should be considered as an anthropological marker. This multi-disciplinary approach combining different fields such as architecture, semiotics and anthropology, is aimed on one hand at contributing to semiotics by proposing a methodology for the analysis of an architectural corpus, and on the other hand, to broadening the field of urban geography to new disciplines, and finally, to providing a new analysis of Beirut’s urban fabric through the comparative case study of two architectural typologies. The proposed semiotic approach can be applied as a tool of urban geography to architectural corpuses and urban fabrics in order to understand the mechanisms of production and obsolescence of form

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Grismayer, Thomas. « Etude théorique et numérique de l'expansion d'un plasma crée par laser : accélération d'ions à haute énergie ». Phd thesis, Ecole Polytechnique X, 2006. http://pastel.archives-ouvertes.fr/pastel-00002924.

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Cette thèse constitue une étude théorique et numérique sur l'accélération d'ions à haute énergie dans l'expansion d'un plasma créé par laser. Les faisceaux d'ions émis en face arrière d'une cible irradiée présentent des caractéristiques (laminarité, faible divergence, largeur des spectres) qui les distinguent de ceux provenant de la face avant. Ces caractéristiques ouvrent la voie à de nombreuses applications telles que la protonthérapie ou la radiographie de protons. L'accélération des ions s'effectue via un champ électrostatique auto-consistant résultant de la séparation de charges entre les ions et les électrons chauds. La première partie du mémoire présente le modèle théorique fluide ainsi que le code de simulation hybride décrivant l'expansion du plasma. La modélisation numérique d'une récente expérience de sondage du champ d'expansion par faisceaux de protons permet de valider le modèle exposé. L'influence d'un gradient initial de densité sur l'efficacité de l'accélération est abordée dans le seconde partie. Nous établissons un modèle qui retrace la dynamique du plasma et plus particulièrement le déferlement du flot ionique. Les réseaux de courbes qui prévoient une nette dégradation de l'énergie maximale des protons pour de grandes longueurs de gradient sont en accord avec les résultats expérimentaux. L'hypothèse d'un équilibre de Boltzmann électronique, supposé dans le modèle guide, est remise en cause dans la troisième partie où les électrons suivent une description cinétique. La nouvelle version du code permet d'évaluer l'écart à la loi de Boltzmann, qui ne modifie pas cependant de manière significative l'énergie maximale acquise par les ions.

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Lalescu, Cristian. « Test particle transport in turbulent magnetohydrodynamic structures ». Doctoral thesis, Universite Libre de Bruxelles, 2011. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/209908.

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Turbulent phenomena are found in both natural (e.g. the Earth's oceans, the Sun's corona) and artificial (e.g. flows through pipes, the plasma in a tokamak device) settings; evidence suggests that turbulence is usually the normal behaviour in most cases. Turbulence has been studied extensively for more than a century, but a complete and consistent theoretical description of it has not yet been proposed. It is in this context that the motion of particles under the influence of turbulent fields is studied in this work, with direct numerical simulations. The thesis is structured in three main parts. The first part describes the tools that are used. Methods of integrating particle trajectories are presented, together with a discussion of the properties that these methods should have. The simulation of magnetohydrodynamic (MHD) turbulence is discussed, while also introducing fundamental concepts of fluid turbulence. Particle trajectory integration requires information that is not readily available from simulations of turbulent flows, so the interpolation methods needed to adapt the fluid simulation results are constructed as well. The second part is dedicated to the study of two MHD problems. Simulations of Kolmogorov flow in incompressible MHD are presented and discussed, and also simulations of the dynamo effect in compressible MHD. These two scenarios are chosen because large scale structures are formed spontaneously by the turbulent flow, and there is an interest in studying particle transport in the presence of structures. Studies of particle transport are discussed in the third part. The properties of the overall approach are first analyzed in detail, for stationary predefined fields. Focus is placed on the qualitative properties of the different methods presented. Charged article transport in frozen turbulent fields is then studied. Results concerning transport of particles in fully developed, time-evolving, turbulent fields are presented in the final chapter.

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Doctorat en Sciences
info:eu-repo/semantics/nonPublished

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Zima, Petr. « (Konformní) Killingovy spinor hodnotové formy na Riemannovských varietách ». Master's thesis, 2014. http://www.nusl.cz/ntk/nusl-340895.

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The goal of the present thesis is to introduce on a Riemannian Spin- manifold a system of partial differential equations for spinor-valued differ- ential forms called Killing equations. We study basic properties of several types of Killing fields and relationships among them. We provide a simple construction of Killing spinor-valued forms from Killing spinors and Killing forms. We also review the construction of metric cone and discuss the re- lationship between Killing spinor-valued forms on the base manifold and parallel spinor-valued forms on the metric cone.

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(11187477), Jin Wu. « Invariant Signatures for Supporting BIM Interoperability ». Thesis, 2021.

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Building Information Modeling (BIM) serves as an important media in supporting automation in the architecture, engineering, and construction (AEC) domain. However, with its fast development by different software companies in different applications, data exchange became labor-intensive, costly, and error-prone, which is known as the problem of interoperability. Industry foundation classes (IFC) are widely accepted to be the future of BIM in solving the challenge of BIM interoperability. However, there are practical limitations of the IFC standards, e.g., IFC’s flexibility creates space for misuses of IFC entities. This incorrect semantic information of an object can cause severe problems to downstream uses. To address this problem, the author proposed to use the concept of invariant signatures, which are a new set of features that capture the essence of an AEC object. Based on invariant signatures, the author proposed a rule-based method and a machine learning method for BIM-based AEC object classification, which can be used to detect potential misuses automatically. Detailed categories for beams were tested to have error-free performance. The best performing algorithm developed by the methods achieved 99.6% precision and 99.6% recall in the general building object classification. To promote automation and further improve the interoperability of BIM tasks, the author adopted invariant signature-based object classification in quantity takeoff (QTO), structural analysis, and model validation for automated building code compliance checking (ACC). Automation in such BIM tasks was enabled with high accuracy.

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Chou, Pei-Yin, et 周珮吟. « A Rotationally Invariant Binary Descriptor Using Pore-Valley Disk Code Structure on Partial Fingerprints ». Thesis, 2017. http://ndltd.ncl.edu.tw/handle/ay4shx.

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« Estruturas quase hermitianas invariantes e ideais abelianos ». Tese, Biblioteca Digital da Unicamp, 2003. http://libdigi.unicamp.br/document/?code=vtls000279879.

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« Teoria geometrica dos invariantes e representações de quivers ». Tese, Biblioteca Digital da Unicamp, 2006. http://libdigi.unicamp.br/document/?code=vtls000383572.

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Silva, Michael Simões. « Validation of Data Invariants in the OutSystems Platform ». Master's thesis, 2019. http://hdl.handle.net/10362/113610.

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Software systems collect information from multiple sources, both internal and exter nal. Therefore, it is indispensable that the data should be validated according to data invariants, in all untrusted frontiers of a system. Developers need to define the validation logic for each of those constraints and to write the actual validation code. To safeguard data integrity throughout the entire system, the developers also need to ensure validation in different layers. This obligation can easily head to a problem since it usually leads to duplication of the validation code and contributes to more complex and less structured software architecture, which consequently leads to systems harder to maintain. The OutSystems platform enables visual development of enterprise Web and Mobile applications, providing an abstraction layer that allows developers to handle the inherent complexity of application development more easily. Still, developers need to write the code responsible for validating data explicitly. We propose an invariant propagation mechanism capable of propagating data con straints across the various layers of a system, that materialises into the automatic gen eration of validation code that properly ensures the data integrity in the entire system. Given a set of data constraints, or invariants, defined in the data layer that constrain entities’ attributes, our mechanism propagates and manipulates their specification. The propagation is done using a path-sensitive data flow analysis technique, specified in Dat alog and that uses a Prolog engine as the resolution engine. This solution ensures that the developer only needs to define the data invariants and their logic once in the entire application, and also ensures that it will generate validations whenever necessary. Thus, we remove the programmer’s obligation of writing and maintaining validation code, plus ensuring data integrity and providing faster error feedback to users. We evaluated our results in a prototype of the OutSystems platform.

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« Espaços de Poisson-Furstenberg e medidas invariantes para grupos de Lie semi-simples ». Tese, Biblioteca Digital da Unicamp, 2005. http://libdigi.unicamp.br/document/?code=vtls000349422.

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