Дисертації з теми "Metodi topologici"
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Corsato, Chiara. "Mathematical analysis of some differential models involving the Euclidean or the Minkowski mean curvature operator." Doctoral thesis, Università degli studi di Trieste, 2015. http://hdl.handle.net/10077/11127.
Повний текст джерелаQuesta tesi è dedicata allo studio di alcuni modelli differenziali che nascono nell'ambito della fluidodinamica o della relatività generale e che coinvolgono gli operatori di curvatura media nello spazio $N$-dimensionale euclideo o di Minkowski. Entrambi sono operatori ellittici quasi-lineari che non soddisfano la proprietà di uniforme ellitticità, essendo l'operatore di curvatura media euclidea degenere, mentre quello di curvatura media nello spazio di Minkowski singolare. Il lavoro è suddiviso in tre parti. La prima riguarda lo studio delle soluzioni periodiche dell'equazione di curvatura prescritta unidimensionale nello spazio euclideo, equazione che modellizza fenomeni di tipo capillarità. In accordo con la struttura dell'operatore di curvatura e imponendo un opportuno comportamento in 0, o all'infinito, della curvatura prescritta, si dimostra l'esistenza di infinite soluzioni subarmoniche classiche arbitrariamente piccole aventi opportune proprietà nodali, oppure di infinite soluzioni subarmoniche a variazione limitata con oscillazioni arbitrariamente grandi. La tecnica per la ricerca delle soluzioni classiche è topologica e si basa sull'uso del numero di rotazione e su una generalizzazione del teorema di Poincaré-Birkhoff; d'altro lato l'approccio per lo studio delle soluzioni non classiche poggia sulla teoria dei punti critici per funzionali non lisci, in particolare su un lemma di passo di montagna nello spazio delle funzioni a variazione limitata. La seconda parte della tesi è dedicata allo studio del problema di Dirichlet omogeneo associato a un'equazione della curvatura media prescritta anisotropa nello spazio euclideo, il quale fornisce un modello di descrizione della geometria della cornea umana. Il problema è ambientato in un dominio regolare in $\mathbb{R}^N$ con frontiera lipschitziana. Il capitolo è suddiviso a sua volta in tre sezioni, che sono rispettivamente focalizzate sui casi unidimensionale, radiale e $N$-dimensionale. Nel caso unidimensionale e nel caso radiale in una palla, si dimostrano l'esistenza e l'unicità di una soluzione classica, che presenta alcune proprietà qualitative aggiuntive. Le tecniche usate in questo contesto sono di natura topologica. Infine, nel caso $N$-dimensionale in un dominio generale, si provano l'esistenza, l'unicità e la regolarità di una soluzione di tipo forte del problema. In relazione ai possibili fenomeni di scoppio del gradiente, l'approccio è variazionale nello spazio delle funzioni a variazione limitata. Si enunciano e si dimostrano prima di tutto alcuni risultati preliminari riguardo al comportamento del funzionale associato al problema; tra questi, si sottolinea l'importanza di una proprietà di approssimazione. Successivamente si provano l'esistenza e l'unicità del minimizzante globale del funzionale, che è regolare all'interno ma non necessariamente sulla frontiera, e soddisfa il problema secondo un'opportuna definizione. Infine si mostra l'unicità della soluzione del problema. Sotto alcune ipotesi rafforzate sulla geometria del dominio, la soluzione ottenuta è classica. La terza parte della tesi riguarda il problema di Dirichlet associato a un'equazione della curvatura media prescritta nello spazio di Minkowski, che è di interesse in relatività generale. Il problema è ambientato in un dominio limitato regolare in $\mathbb{R}^N$ e un modello di curvatura media prescritta è dato da una funzione $f(x,s)$ che può avere comportamento sublineare, lineare, superlineare o sub-superlineare in $s=0$. L'attenzione è rivolta all'esistenza e alla molteplicità di soluzioni positive del problema. Come il precedente, anche questo capitolo è suddiviso in tre sezioni, che trattano rispettivamente i casi unidimensionale, radiale e $N$-dimensionale in un dominio generale. Nel caso unidimensionale, viene impiegato un approccio di tipo mappa-tempo per studiare una semplice situazione autonoma. Nel caso radiale in una palla, la tecnica è variazionale e lo studio del funzionale associato al problema evidenzia l'esistenza di un punto critico (casi sublineare o lineare), o di due (caso superlineare), o di tre punti critici (caso sub-superlineare): ciascuno di questi è una soluzione positiva del problema. Infine, nel caso generale in dimensione $N$, si adotta un approccio topologico che permette di studiare il problema non variazionale, in cui la funzione $f$ può dipendere dal gradiente della soluzione. Più nel dettaglio, con un metodo di sotto- e sopra-soluzioni specificamente sviluppato per questo problema, proviamo vari risultati di esistenza, molteplicità e localizzazione, in relazione alla presenza di una singola sotto-soluzione, o di una singola sopra-soluzione, o di una coppia di sotto- e sopra-soluzione ordinate o non ordinate. L'Appendice chiude la tesi: qui sono raccolti vari strumenti matematici utilizzati nel corso del lavoro.
This thesis is devoted to the study of some differential models arising in fluid mechanics or general relativity and involving the mean curvature operators in the $N$-dimensional Euclidean or Minkowski spaces. In both cases the operators are quasilinear elliptic operators which do not satisfy the property of uniform ellipticity, the Euclidean mean curvature operator being degenerate, whereas the Minkowski mean curvature operator being singular. This work is subdivided into three parts. The first one concerns the study of the periodic solutions of the one-dimensional prescribed curvature equation in the Euclidean space, which models capillarity-type phenomena. According to the structure of the curvature operator and imposing a suitable behaviour at zero, or at infinity, of the prescribed curvature, we prove the existence of infinitely many arbitrarily small classical subharmonic solutions with suitable nodal properties, or bounded variation subharmonic solutions with arbitrarily large oscillations. The technique for the search of classical solutions is topological and relies on the use of the rotation number and on a generalization of the Poincaré-Birkhoff theorem; whereas the approach for the study of non-classical solutions is based on non-smooth critical point theory, namely on a mountain pass lemma set in the space of bounded variation functions. The second part of the thesis is devoted to the study of the homogeneous Dirichlet problem associated with an anisotropic prescribed mean curvature equation in the Euclidean space, which provides a model for describing the geometry of the human cornea. The problem is set in a bounded domain in $\mathbb{R}^N$ with Lipschitz boundary. This chapter is subdivided into three sections, which are focused on the one-dimensional, the radial and the general $N$-dimensional case, respectively. In the one-dimensional and in the radial case in a ball, we prove an existence and uniqueness result of classical solution, which also displays some additional qualitative properties. Here the techniques used are topological in nature. Finally, in the $N$-dimensional case, we prove the existence, the uniqueness and the regularity of a strong-type solution of the problem. In order to tackle the possible gradient blow-up phenomena, the approach is variational and the framework is the space of bounded variation functions. We first collect some preliminary results about the behaviour of the action functional associated with the problem; among them, we remark the importance of an approximation property. We then prove the existence and uniqueness of the global minimizer of the action functional, which is smooth in the interior but non necessarily on the boundary, and satisfies the problem in a suitable sense. We finally prove the uniqueness of solution. Under some strengthened assumptions on the geometry of the domain, the solution obtained is classical. The third part of the thesis deals with the Dirichlet problem associated with a prescribed mean curvature equation in the Minkowski space, which is of interest in general relativity. The problem is set in a bounded regular domain in $\mathbb{R}^N$ and a model prescribed curvature is given by a function $f(x,s)$ whose behaviour is sublinear, linear, superlinear or sub-superlinear at $s=0$. The attention is addressed towards the existence and the multiplicity of positive solutions of the problem. In parallel to the second part of the thesis, this chapter is subdivided into three sections, which are focused on the one-dimensional, the radial and the general $N$-dimensional case, respectively. In the one-dimensional case, a time-map approach is employed for treating a simple autonomous situation. In the radial case in a ball, the technique is variational and the study of the action functional associated with the problem evidences the existence of either one (sublinear or linear cases), or two (superlinear case), or three (sub-superlinear case) non-trivial critical points of the action functional: each of them is a positive solution of the problem. Finally, in the general $N$-dimensional case, we adopt a topological approach which allows to study the non-variational problem, where the function $f$ may also depend on the gradient of the solution. Namely, by a lower and upper solution method specifically developed for this problem, we prove several existence, multiplicity and localization results, in relation to the presence of a single lower solution, or a single upper solution, or a couple of ordered or non-ordered lower and upper solutions of the problem. The Appendix completes this thesis: here several mathematical tools that have been used to prove the results are collected.
XXVI Ciclo
1986
Shi, Lingsheng. "Numbers and topologies." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät II, 2003. http://dx.doi.org/10.18452/14871.
Повний текст джерелаIn graph Ramsey theory, Burr and Erdos in 1970s posed two conjectures which may be considered as initial steps toward the problem of characterizing the set of graphs for which Ramsey numbers grow linearly in their orders. One conjecture is that Ramsey numbers grow linearly for all degenerate graphs and the other is that Ramsey numbers grow linearly for cubes. Though unable to settle these two conjectures, we have contributed many weaker versions that support the likely truth of the first conjecture and obtained a polynomial upper bound for the Ramsey numbers of cubes that considerably improves all previous bounds and comes close to the linear bound in the second conjecture. In topological Ramsey theory, Kojman recently observed a topological converse of Hindman's theorem and then introduced the so-called Hindman space and van der Waerden space (both of which are stronger than sequentially compact spaces) corresponding respectively to Hindman's theorem and van der Waerden's theorem. In this thesis, we will strengthen the topological converse of Hindman's theorem by using canonical Ramsey theorem, and introduce differential compactness that arises naturally in this context and study its relations to other spaces as well. Also by using compact dynamical systems, we will extend a classical Ramsey type theorem of Brown and Hindman et al on piecewise syndetic sets from natural numbers and discrete semigroups to locally connected semigroups.
Porto, Eduardo Castelo Branco. "Metodo da homogeneização aplicado a otimização estrutural topologica." [s.n.], 2006. http://repositorio.unicamp.br/jspui/handle/REPOSIP/265173.
Повний текст джерелаDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica
Made available in DSpace on 2018-08-07T01:37:07Z (GMT). No. of bitstreams: 1 Porto_EduardoCasteloBranco_M.pdf: 1249639 bytes, checksum: ecf2198ecf41330cd50bfdb24c3bdb08 (MD5) Previous issue date: 2006
Resumo: Este trabalho tem por objetivos a investigação e a implementação de um método de otimização estrutural topológica baseado no uso de microestruturas. Dois modelos de microestrutura são introduzidos no problema de projeto ótimo: um ortotrópico com vazios, via homogeneização, e outro isotrópico com penalidade, via equação constitutiva artificial. As propriedades mecânicas efetivas de tais modelos são determinadas através de um programa iterativo implementado, baseado na abordagem da homogeneização. A análise estrutural é então realizada através do método dos elementos finitos e a topologia ótima é obtida com o uso de um otimizador baseado em critérios de otimalidade. São feitas investigações acerca dos parâmetros envolvidos na técnica de homogeneização, assim como são resolvidos problemas elastoestáticos e elastodinâmicos lineares de estado plano de tensão envolvendo critérios de projeto em rigidez e em freqüência natural e restrição de volume. Os algoritmos, implementados em ambiente Matlab, têm sua eficácia comprovada mediante a resolução de problemas clássicos existentes na literatura. E com a implementação dos modelos de material ortotrópico com vazios e isotrópico com penalidade é possível explorar as principais características e potencialidades de cada abordagem
Abstract: This work aims to investigate and implement a structural topology optimization method based on microstructures. Two microstructure models are introduced in the optimal design problem: one orthotropic with holes, by homogenization, and other isotropic with penalization, by artificial constitutive equation. An implemented iterative program, based on the homogenization approach, determines the effective mechanical properties of each material model. Structural analyses are performed by using the finite element method and optimal topologies are obtained using an optimizer based on optimality criteria. Investigations concerning the parameters related to the homogenization technique are carried out. Linear elastic static and dynamic problems of structures in plane stress state are solved as well, concerning stiffness and natural frequency design criteria and with a constraint on volume. The solution of classic structural problems encountered in literature has demonstrated the effectiveness of the implemented Matlab codes and the implementation of the orthotropic and isotropic material models has made possible the investigation of the main characteristics and potentialities of each approach
Mestrado
Mecanica dos Sólidos e Projeto Mecanico
Mestre em Engenharia Mecânica
Starodubtsev, Artem. "Topological methods in quantum gravity." Thesis, University of Waterloo, 2005. http://hdl.handle.net/10012/1217.
Повний текст джерелаMagnifico, Giuseppe <1991>. "Quantum simulation and topological phases in Lattice Gauge Theories." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2020. http://amsdottorato.unibo.it/9254/1/tesi.pdf.
Повний текст джерелаJakobsen, Alexander M. "Topological methods of preference and judgment aggregation." Thesis, University of British Columbia, 2011. http://hdl.handle.net/2429/35592.
Повний текст джерелаLeventides, J. "Algebrogeometric and topological methods in control theory." Thesis, City University London, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.358988.
Повний текст джерелаSafa, Issam I. "Towards Topological Methods for Complex Scalar Data." The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1322457949.
Повний текст джерелаVála, Pavel. "Optimalizace vlastností snímače vektoru kontaktní síly." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2008. http://www.nusl.cz/ntk/nusl-228264.
Повний текст джерелаMillo, Raffaele. "Topological Dynamics in Low-Energy QCD." Doctoral thesis, Università degli studi di Trento, 2011. https://hdl.handle.net/11572/368358.
Повний текст джерелаKirtschig, Frank. "Topological k.p Hamiltonians and their applications to uniaxially strained Mercury telluride." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2017. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-226489.
Повний текст джерелаKordula, Tomáš. "Optimalizace topologie kmitajícího nosníku složeného z více materiálů." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2020. http://www.nusl.cz/ntk/nusl-418195.
Повний текст джерелаEnqvist, Per. "Spectral Estimation by Geometric, Topological and Optimization Methods." Doctoral thesis, Stockholm, 2001. http://media.lib.kth.se:8080/kthdisseng.html.
Повний текст джерелаMurolo, Giuseppe. "Metodi matematici per l'analisi dell'andatura." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2019. http://amslaurea.unibo.it/18224/.
Повний текст джерелаBhalekar, Aniruddha Ramesh. "Internet content delivery acceleration methods for hybrid network topologies." College Park, Md. : University of Maryland, 2003. http://hdl.handle.net/1903/132.
Повний текст джерелаThesis research directed by: Electrical and Computer Engineering. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
Yiu, Paul Yu-Hung. "Topological and combinatoric methods for studying sums of squares." Thesis, University of British Columbia, 1985. http://hdl.handle.net/2429/26037.
Повний текст джерелаScience, Faculty of
Mathematics, Department of
Graduate
Brodsky, Valery. "Optimization methods for topological design of interconnected ring networks." Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/32594.
Повний текст джерелаIncludes bibliographical references (leaves 177-179).
by Valery Brodsky.
M.S.
Goodarzi, Afshin. "Topological and Shifting Theoretic Methods in Combinatorics and Algebra." Doctoral thesis, KTH, Matematik (Inst.), 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-186136.
Повний текст джерелаQC 20160516
Oancea, Ionela. "Topological analysis of metabolic and regulatory networks by decomposition methods." [S.l. : s.n.], 2003. http://deposit.ddb.de/cgi-bin/dokserv?idn=972540172.
Повний текст джерелаWeidig, Tom. "Classical and quantum aspects of topological solitons (using numerical methods)." Thesis, Durham University, 1999. http://etheses.dur.ac.uk/4277/.
Повний текст джерелаWang, Suyi Wang. "Analyzing data with 1D non-linear shapes using topological methods." The Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1524020976023345.
Повний текст джерелаSantos, Sandrina Rafaela Andrade. "Nonlinear elliptic equations with nonsmooth potential : variational and topological methods." Doctoral thesis, Universidade de Aveiro, 2009. http://hdl.handle.net/10773/2945.
Повний текст джерелаNesta tese de doutoramento, estudamos a existência e a multiplicidade de soluções para algumas classes de equações elípticas não lineares com potencial não suave. Os resultados originais foram obtidos, utilizando métodos variacionais e da teoria de grau. A nossa abordagem variacional é baseada em descobertas recentes na teoria não suave (nonsmooth) dos pontos críticos. A teoria de grau é aplicada a determinadas perturbações multívocas de operadores de tipo monótono (operadores do tipo (S)+ ). O primeiro problema que consideramos é um problema de valor próprio semi-linear com potencial não suave (ver Capítulo 3). O resultado de existência obtido estende para uma versão não suave, e sob hipóteses de crescimento mais fracas, um resultado obtido por Rabinowitz para potenciais suaves. Mais, sob condições no potencial que permitem ressonância, quer em zero, quer no infinito, provamos um resultado de multiplicidade. Para um problema elíptico não linear derivado do p-Laplaciano e com um potencial não suave (ver Capítulo 4), estabelecemos a existência de, pelo menos, três soluções suaves, não triviais e distintas, sendo duas delas de sinal constante (uma positiva e uma negativa). Problemas semi-lineares de Neumann, que são duplamente ressonantes na origem, relativamente a qualquer intervalo espectral [λk,λk+1], são estudados no Capítulo 5. O resultado de multiplicidade obtido para um potencial não suave estende resultados existentes para o caso do potencial suave, nos quais a ressonância é completa relativamente a λk, mas incompleta relativamente a λk+1. Respondemos afirmativamente à questão aberta em relação à validade do resultado de multiplicidade, quando ocorre, também, ressonância completa relativamente a λk+1 (situação de dupla ressonância). A última parte da tese (Capítulo 6) é dedicada ao estudo de uma classe de problemas de Neumann, em que o operador diferencial não é homogéneo, nem variacional. Portanto, os métodos mini-max da teoria dos pontos críticos (suave e não-suave) não podem ser utilizados. Usando o espectro do operador diferencial assimptótico, juntamente com métodos da teoria de grau, estabelecemos a existência de soluções suaves não triviais.
In this Ph.D. thesis, we study the existence and the multiplicity of solutions to some classes of nonlinear elliptic equations with a nonsmooth potential. Our new results were obtained by using variational and degree theoretic methods. The variational approach we used is based on recent developments in nonsmooth critical point theory. The degree theory we used concerns certain multivalued perturbations of a class of monotone type operators (the (S)+ type operators). The first problem we consider is a semilinear eigenvalue problem with a nonsmooth potential (see Chapter 3). The existence result we obtained extends to nonsmooth setting and under weaker growth assumptions, a result obtained by Rabinowitz for smooth potentials. Moreover, under conditions on the potential which allow resonance both at zero and at infinity, we prove a multiplicity result. For a nonlinear elliptic problem driven by the p-Laplacian and with a nonsmooth potential (see Chapter 4), we establish the existence of at least three distinct nontrivial smooth solutions, two of them with constant sign (one positive and one negative). Semilinear Neumann problems which are doubly resonant at the origin with respect to any spectral interval [λk,λk+1] were studied in Chapter 5. The multiplicity result we obtained for nonsmooth potential, extend results known for the case of smooth potential, where the resonance is complete with respect to λk, but incomplete (nonuniform nonresonance) with respect to λk+1. We give a positive answer to an open question asking whether the multiplicity result also holds when complete resonance occurs also with respect to λk+1 (double resonance situation). The last part of the thesis (Chapter 6) is devoted to the study of a class of Neumann problems where the differential operator driving the problem is neither homogeneous, nor variational. So the minimax methods of critical point theory (smooth and nonsmooth alike) fail. Using the spectrum of the asymptotic differential operator together with degree theoretic methods, we establish the existence of nontrivial smooth solutions.
Oancea, Ionela. "Topological analysis of metabolic and regulatory networks by decomposition methods." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2004. http://dx.doi.org/10.18452/15024.
Повний текст джерелаThe living organisms are too complex when considering them as a whole. The present thesis deals with the topological properties of two important parts of living organisms: the metabolic and the regulatory systems. The topological properties are those features that are determined by the network structure. A classification in metabolic and regulatory systems is often used. A signalling system is a special kind of regulatory system. Between metabolic and signalling networks, there are important differences that impose their treatment in different ways. In metabolic pathway analysis, the elementary flux mode concept is already established as a proper tool for identifying the smallest essential routes in biochemical systems. We examine its features and advantages in some particular cases. Firstly, many enzymes operate with low specificity (e.g. nucleoside diphosphokinase, uridine kinase, transketolase, transaldolase), so that various substrates and products can be converted. Also the enzymatic mechanisms are diverse, as we have illustrated with reaction schemes for bifunctional enzymes. Therefore, there are two different approaches to describe multifunctional enzymes (We considered only the case when a certain active site hosts several reactions. The case when the studied enzyme has several such active sites can be transformed into that of several enzymes having only one active site. If a disease alters the initial enzyme, also all substituting enzymes are altered.): in terms of overall reactions and in terms of reactions steps (hemi-reactions, half-reactions). For enzymes with two or more functions, it is important to consider only linearly independent functions, because otherwise cyclic elementary modes would occur which do not perform any net transformation. However, the choice of linearly independent functions is not a priori unique. In Chapter 2, we give a method for making this choice unique by considering the convex basis of the hemi-reactions system. The set of linearly independent functions provided by our algorithm coincides, in the case of transketolase in pentose phosphate pathway, with the set of linearly independent functions mentioned in literature. A formal application of the algorithm for computing elementary flux modes (pathways) yields the result that the number of such modes sometimes depends on the level of description if some reactions are reversible and the products of the multifunctional enzymes are external metabolites or some multifunctional enzymes partly share the same metabolites. However, this problem can be solved by appropriate interpretation of the definition of elementary modes and the correct choice of independent functions of multifunctional enzymes. The analysis is illustrated by a biochemical example taken from nucleotide metabolism, comparing the two ways of description for nucleoside diphosphokinase and adenylate kinase, and by several smaller examples. The nucleotide metabolism plays an important role in living organisms and is very sensitive to any perturbations in its internal balance. Dangerous diseases may occur if some enzymes do not work properly. With the help of elementary flux mode concept, we explain the occurrence and severity of diseases based on enzyme deficiencies. If an enzyme is completely inhibited, some metabolic routes are blocked. If, however, some alternative routes still exist, the disease is less dangerous. In Chapter 3, we focus on finding alternative routes, essential enzymes and enzymes operating together. The latter notion is also known as ,,enzyme subset`` and represents an intermediary step in calculating the elementary flux modes. The known or hypothesised mechanisms of several disorders, occurred due to the malfunctioning of nucleotide metabolism (proliferative diseases, immunodeficiency diseases) or due to its hijacking by viruses and parasites, are given. Most strategies adopted for curing such diseases are based on nucleotide metabolism interruption. Therefore, a better understanding of this system helps developing more effective drugs and a good structural analysis can spare many experimental efforts. Petri net concepts provide additional tools for the modelling of metabolic networks. In Chapter 4, the similarities between the counterparts in traditional biochemical modelling and Petri net theory are discussed. For example, the stoichiometry matrix of a metabolic network corresponds to the incidence matrix of the Petri net. The flux modes and conservation relations have the T-invariants, respectively, P-invariants as counterparts. We reveal the biological meaning of some notions specific to the Petri net framework (traps, siphons, deadlocks, liveness). We focus on the topological analysis rather than on the analysis of the dynamic behaviour. The treatment of external metabolites is discussed. Some simple theoretical examples are presented for illustration. Also the Petri nets corresponding to some biochemical networks are built to support our results. For example, the role of triose phosphate isomerase (TPI) in Trypanosoma brucei metabolism is evaluated by detecting siphons and traps. All Petri net properties treated in above-mentioned chapter (4) are exemplified on a system extracted from nucleotide metabolism. While for decomposing metabolic systems, many efforts have been done (elementary flux modes, convex basis, extreme pathways), for signalling maps, as far as we know, no attempt in this direction has been made. A special characteristic of signalling networks is that activations, inhibitions, and biochemical reactions are normally present in parallel. Even if they do not contain reactions, multi-part activations or inhibitions make them highly branched. To detect all factors that have an influence on a given target, without using an automatic method, is a difficult and very time-consuming effort. Already in Chapter 1 (Backgrounds), we highlight the similarities and differences between metabolic and signalling networks. In Chapter 5, we build a framework and algorithm for decomposing signalling networks in smaller units, which are easier to study and understand. Two cases are investigated: a simpler one, when only monomolecular activations or reactions are present, and a more complex case, when the activations and reactions can be multimolecular. Their description requires different instruments: classical graphs and Petri nets, respectively. We discuss the problems that occur in our model due to the presence of some inhibitions or unknown effects in the network. The algorithm that we propose detects the factors that are acting together and the targets that are affected on the same route. The cycles that occur in the system are also highlighted. We point out possible missing reactions. Theoretical examples illustrate out findings. Using the T cell antigen-receptor signalling cascade, we show how it can be applied to real systems.
Johansson, Gunnar. "Local Level Set Segmentation with Topological Structures." Thesis, Linköping University, Department of Science and Technology, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-6904.
Повний текст джерелаLocating and segmenting objects such as bones or internal organs is a common problem in medical imaging. Existing segmentation methods are often cumbersome to use for medical staff, since they require a close initial guess and a range of different parameters to be set appropriately. For this work, we present a two-stage segmentation framework which relies on an initial isosurface interactively extracted by topological analysis. The initial isosurface seldom provides a correct segmentation, so we refine the surface using an iterative level set method to better match the desired object boundary. We present applications and improvements to both the flexible isosurface interface and level set segmentation without edges.
Karapiperi, Anna. "Extrapolation methods and their applications in numerical analysis and applied mathematics." Doctoral thesis, Università degli studi di Padova, 2016. http://hdl.handle.net/11577/3424504.
Повний текст джерелаQuesta tesi di dottorato tratta alcune applicazioni dei metodi di estrapolazione. Spesso in analisi numerica e nella matematica applicata si devono trattare successioni che convergono lentamente al loro limite. I metodi di estrapolazione possono essere utilizzati per accelerare la convergenza di una successione che converge lentamente o anche per sommare serie divergenti. I primi due capitoli della tesi sono dedicati alle trasformazioni di successioni scalari. Viene ripreso il Δ2 di Aitken e vengono proposte tre nuove trasformazioni che lo generalizzano. Le proprietà di convergenza e di accelerazione di una delle trasformazioni sono discusse teoricamente e verificate sperimentalmente usando delle successioni divergenti e convergenti. La trasformazione di Shanks e l'ε-algorithm di Wynn sono accuratamente studiati; vengono richiamate le regole particolari proposte da Wynn per il trattamento delle singolarità isolate, ovvero quando due elementi consecutivi sono uguali o quasi uguali, ed anche le regole particolari, più generali, proposte da Cordellier, per il trattamento delle singolarità non isolate, ovvero quando più di due elementi sono uguali. Viene proposta una nuova generale implementazione delle regole particolari in modo da poter trattare tutti i casi possibili, ossia la presenza di singolarità causata da due o più elementi che sono uguali o quasi uguali. Nella parte rimanente della tesi ci si concentra sull'estrapolazione vettoriale. Prima vengono brevemente descritti l'ε-algorithm vettoriale, l'ε-algorithm topologico e la sua versione semplificata, recentemente introdotta da Brezinski e Redivo-Zaglia. Successivamente, vengono presentate, con una notazione unificata le Algebraic Reconstruction Techniques (ART), le Simultaneous Iterative Reconstruction Techniques (SIRT) e altri metodi iterativi di regolarizzazione, che sono comunemente utilizzati per risolvere problemi inversi lineari. Infine, vengono illustrati i vantaggi ottenuti applicando l'estrapolazione ai precedenti metodi iterativi, utilizzati su problemi relativi alle immagini. In particolare, viene utilizzato il simplified topological ε-algorithm al fine di estrapolare una successione generata da metodi di tipo Landweber e Cimmino quando si risolvono problemi di ricostruzione e di restauro di immagini. I risultati numerici mostrano un buon comportamento dei metodi accelerati rispetto alle loro versioni non accelerate ed anche rispetto ad altri metodi.
BLASI, Gianmichele. "Nonlocal Thermoelectricity and Entanglement in Topological Josephson junctions." Doctoral thesis, Scuola Normale Superiore, 2021. http://hdl.handle.net/11384/108564.
Повний текст джерелаSeepersad, Carolyn Conner. "A Robust Topological Preliminary Design Exploration Method with Materials Design Applications." Diss., Georgia Institute of Technology, 2004. http://hdl.handle.net/1853/4868.
Повний текст джерелаHaase, Albert Alfred [Verfasser]. "New Applications of Topological Methods in Discrete Geometry / Albert Alfred Haase." Berlin : Freie Universität Berlin, 2017. http://d-nb.info/1136319344/34.
Повний текст джерелаWang, Yuan, and 王瑗. "Topological degree methods in the existence studies of P-laplacian equations." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2010. http://hub.hku.hk/bib/B44545691.
Повний текст джерелаHaase, Albert [Verfasser]. "New Applications of Topological Methods in Discrete Geometry / Albert Alfred Haase." Berlin : Freie Universität Berlin, 2017. http://d-nb.info/1136319344/34.
Повний текст джерелаLindell, Erik. "Decomposition Methods for Representations of Quivers appearing in Topological Data Analysis." Thesis, KTH, Skolan för teknikvetenskap (SCI), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-210863.
Повний текст джерелаFRASSU, SILVIA. "Dirichlet problems for several nonlocal operators via variational and topological methods." Doctoral thesis, Università degli Studi di Cagliari, 2021. http://hdl.handle.net/11584/309589.
Повний текст джерелаMesquita, Gustavo Henrique Jesus. "Otimização topológica de absorvedores dinâmicos de vibrações sujeito a vibração livre e forçada." Universidade Federal de Goiás, 2016. http://repositorio.bc.ufg.br/tede/handle/tede/6283.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES
The aim of this work is to propose a methodology of application of the FEM and topology optimization technique as tools of analysis and optimal design of mechanical systems subject to natural and forced vibrations in order to reach the optimal geometry of a dynamic absorbing of vibrations. It presents the mathematical reasoning and develop a program in Matlab® that implements the topology optimization technique will be employed to generate the optimal material distribution ( layout ) continuous mechanical systems without external excitation and subject to harmonic forces with preset frequency.
Propõe-se uma metodologia de aplicação do MEF (Método dos Elementos Finitos), juntamente com uma técnica de otimização topológica como ferramenta de análise e projeto ótimo de sistemas mecânicos sujeitos a vibração forçada. Em particular, chega-se à geometria ótima de um absorvedor dinâmico de vibrações contínuo. Apresenta-se a modelagem matemática, além de se desenvolver um código em Matlab® que implementa a técnica de otimização topológica por distribuição de material aplicado a sistemas mecânicos contínuos com excitação externa e harmônica de tal forma que a menor frequência natural seja predefinida.
Zhu, Lierong. "Topological visualization of tensor fields using a generalized Helmholtz decomposition." Morgantown, W. Va. : [West Virginia University Libraries], 2010. http://hdl.handle.net/10450/10962.
Повний текст джерелаTitle from document title page. Document formatted into pages; contains viii, 75 p. : ill. (some col.). Includes abstract. Includes bibliographical references (p. 72-75).
Grabel, Michael Z. "A Lagrangian/Eulerian Approach for Capturing Topological Changes in Moving Interface Problems." University of Cincinnati / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1563527241172213.
Повний текст джерелаWierzbicki, Madalina Nicoleta. "Topologies and design methods for folding kinetic structures : expanding the architectural paradigm." Thesis, University of British Columbia, 2014. http://hdl.handle.net/2429/45748.
Повний текст джерелаAndreeta, Mariane Barsi. "Topological study of reservoir rocks and acidification processes using complex networks methods." Universidade de São Paulo, 2017. http://www.teses.usp.br/teses/disponiveis/76/76132/tde-30012018-154357/.
Повний текст джерелаA microtomografia de raios-X permitiu a evolução de uma nova área da ciência aplicada a meios porosos: a Rocha Digital. Através desta técnica, todo o espaço poroso é recuperado, e é possível entender a dinâmica do fluido que o permeia através de simulações computacionais. No entanto, ainda há a questão de como a estrutura do meio influencia nos resultados observados. Entender questões como connectividade e clusterização de regiões podem dar informações valiosas sobre como a origem do meio poroso influencia na dinâmica do fluido que o permeia. Esta avaliação do meio é possível através da simplificação do mesmo em uma rede de conexão de elementos básicos e as interações entre estes. O problema com a descrição do meio poroso em uma rede de conexão é que não existe um consenso na definição destes elementos básicos. O propósito deste trabalho foi encontrar uma maneira de descrever o meio que fosse aplicável a qualquer litologia, e que se aproximasse ao máximo dos dados extraídos pela micro tomografia para a análise das topologias de diferentes rochas através de teoria de redes complexas.Para isso, utilizamos o algoritmo robusto de extração de redes de poros, esferas máximas, como base para dividir o espaço-poroso em células esféricas. Desta forma, todo o volume do espaço poroso observado através da micro tomografia é recuperado e descrito em uma rede de conexão. O resultado final do método aplicado é uma rede que descreve o meio completo e uma rede que descreve o eixo medial das interconexões entre poros. A geometria local dos poros é recuperada através de um critério de centralidade de rede, assim a separação é governada pela morfologia intrínseca das amostras, ao invés de fatores geométricos.Desta forma podemos analisar o efeito da tortuosidade real do meio, assim como a interconexão entre poros, com relação a permeabilidade do meio.O método se mostrou eficaz na análise de rochas com diferentes litologias: arenito (Berea) e carbonato (Estaillades). O método também foi aplicado na avaliação da estrutura de canais formados pelo processo de acidificação de rochas (wormholes).
Du, Jia-Zheng. "Methods and software development for sectional and topological optimization of frame structures." Reims, 2004. http://theses.univ-reims.fr/exl-doc/GED00000024.pdf.
Повний текст джерелаTo satisfy the requirement on computation and optimization of frame structures in the engineering field, some sectional and topological optimization methods of frame structures are studied and a relevant software based on the present study is developed using the MSC/Patran&Nastran software as platform. Combining the optimality criteria method and the mathematical programming method, several methods are adopted to deal with the constraints with different properties. The original sectional optimization model is transformed into a dual problem according to the dual theory in order to reduce the number of the design variables so speed up the resolution. The methods of Approximate Scaling Step and Deletion of Negative Constraints also largely improve the efficiency. Based on the ICM (Independent Continuous Mapping) method, a topological optimization model with continuous topological variables (between 0 and 1 instead of 0 or 1) is built. In order to quickly and accurately obtain the optimum topological structures, three criteria are introduced and a self-adaptive algorithm is proposed. To deal with the elements with their null topological variable, the weak material method is proposed and compared with the tiny section method. The topological optimization for multi-loading cases is studied with three conditions: the local stress constraints, the global displacement constraints and their combination. According to the above methods, the MSC/Patran&Nastran software is secondly developed. The examples clearly show the notable improvement of the efficiency and accuracy
Wintz, Julien. "Algebraic methods for geometric modeling." Nice, 2008. http://www.theses.fr/2008NICE4005.
Повний текст джерелаLes domaines de géométrie algébrique et de géométrie algorithmique, bien qu'étroitement liés, sont traditionnellement représentés par des communautés de recherche disjointes. Chacune d'entre elles utilisent des courbes et surfaces, mais représentent les objets de différentes manières. Alors que la géométrie algébrique définit les objets par le biais d'équations polynomiales, la géométrie algorithmique a pour habitude de manipuler des modèles linéaires. La tendance actuelle est d'appliquer les algorithmes traditionnels de géométrie algorithmique sur des modèles non linéaires tels que ceux trouvés en géométrie algébrique. De tels algorithmes jouent un rôle important dans de nombreux champs d'application tels que la Conception Assistée par Ordinateur. Leur utilisation soulève d'importantes questions en matière de développement logiciel. Tout d'abord, la manipulation de leur représentation implique l'utilisation de calculs symboliques numériques qui représentent toujours un domaine de recherche majeur. Deuxièmement, leur visualisation et leur manipulation n'est pas évidente, en raison de leur caractère abstrait. La première partie de cette thèse porte sur l'utilisation de méthodes algébriques en modélisation géométrique, l'accent étant mis sur la topologie, l'intersection et l'auto-intersection dans le cadre du calcul d'arrangement d'ensembles semi-algébriques comme les courbes et surfaces à représentation implicite ou paramétrique. Une attention particulière est portée à la généricité des algorithmes qui peuvent être spécifiés quel que soit le contexte, puis spécialisés pour répondre aux exigences d'une certaine représentation. La seconde partie de cette thèse présente le prototypage d'un environnement de modélisation géométrique dont le but est de fournir un moyen générique et efficace pour modéliser des solides à partir d'objets géométriques à représentation algébrique tels que les courbes et surfaces implicites ou paramétriques, à la fois d'un point de vue utilisateur et d'un point de vue de développeur, par l'utilisation de librairies de calcul symbolique numérique pour la manipulation des polynômes définissant les objets géométriques
Bridgeman, Jacob. "Tensor Network Methods for Quantum Phases." Thesis, The University of Sydney, 2017. http://hdl.handle.net/2123/17647.
Повний текст джерелаROSA, DARIO. "From spinors to forms: results on g-structures in supergravity and on topological field theories." Doctoral thesis, Università degli Studi di Milano-Bicocca, 2014. http://hdl.handle.net/10281/55207.
Повний текст джерелаLe, Huy. "Numerické metody měření fraktálních dimenzí a fraktálních měr." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2020. http://www.nusl.cz/ntk/nusl-417160.
Повний текст джерелаSaikia, Himangshu. "Comparison and Tracking Methods for Interactive Visualization of Topological Structures in Scalar Fields." Doctoral thesis, KTH, Beräkningsvetenskap och beräkningsteknik (CST), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-216375.
Повний текст джерелаQC 20171020
Deshpande, D. V. "Topological methods in algebraic geometry : cohomology rings, algebraic cobordism and higher Chow groups." Thesis, University of Cambridge, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.598515.
Повний текст джерелаNygren, Johan, and Kalle Masth. "Jammets Topologi : Från Jam Session till South Park." Thesis, Blekinge Tekniska Högskola, Institutionen för teknik och estetik, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:bth-10765.
Повний текст джерелаIn this thesis we will study Game/Media-Jams, Hackathons and similar concepts and try to establisha method to create a model for their topology. We intend to investigate what these concepts have incommon through their rules and compare that to Jam Sessions. Following this we will try to extractthe purpose of the rules. These purposes will then be put in topologically measurable intervals thatcan be transfered onto the topological model. The results will then be used to compareJams/Hackathons, similar concepts and events that only have a few things in common with Jams, tosee if the model can determine if an event is in the spirit of a Jam without actually being one.
Jung, JiYoon. "ANALYTIC AND TOPOLOGICAL COMBINATORICS OF PARTITION POSETS AND PERMUTATIONS." UKnowledge, 2012. http://uknowledge.uky.edu/math_etds/6.
Повний текст джерелаde, Silva Hidda Marakkala Gayan Ruchika. "Analýza síťové bezpečnosti." Doctoral thesis, Vysoké učení technické v Brně. Fakulta informačních technologií, 2012. http://www.nusl.cz/ntk/nusl-261266.
Повний текст джерелаCarbas, Serdar. "Optimum Topological Design Of Geometrically Nonlinear Single Layer Lamella Domes Using Harmony Search Method." Master's thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/12609634/index.pdf.
Повний текст джерелаStovner, Roar Bakken. "On the Mapper Algorithm : A study of a new topological method for data analysis." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for matematiske fag, 2012. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-19351.
Повний текст джерелаVeeramalai, Mallika. "A novel method for comparing topological models of protein structures enhanced with ligand information." Thesis, University of Glasgow, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.443432.
Повний текст джерела