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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
91

Calçadões: a revitalização urbana e a valorização das estruturas comerciais em áreas centrais / Pedestrian malls: the urban revitalization and valueing of commercial structures in dowtown areas

Januzzi, Denise de Cassia Rossetto 25 August 2006 (has links)
Este trabalho traz uma investigação sobre as ruas de pedestres e as mudanças que elas provocam no centro de uma cidade. O objetivo da pesquisa foi verificar os aspectos positivos e os negativos da implantação de uma rua de pedestres, como forma de buscar subsídios para a implantação e manutenção desses espaços. O objeto principal desta pesquisa é a rua de pedestres de Londrina-PR, sendo a rua de pedestres de Bauru-SP o objeto secundário. Foi feita uma análise comparativa entre as duas. A pesquisa teve por base três tipos de análises: a da autora, a aplicação de questionários e a elaboração de mapas comportamentais, o que possibilitou o cruzamento das informações levando em consideração diferentes pontos de vista o do pesquisador e o do usuário. O trabalho procurou verificar, sobretudo, como um projeto de revitalização urbana contribui para ampliar a qualidade dos espaços urbanos. / This work investigates pedestrian malls and the changes they bring about to downtown areas. The objective of the research was to verify the positive and negative aspects of pedestrian mall implementation and maintenance. The main focus of this study is a pedestrian mall located in Londrina, Paraná, having another pedestrian mall located in Bauru, São Paulo as a secondary object of study. A comparative study of the two walks was carried out using three types of analyses: personal ( by the author of this study ), questionnaires and behavior maps . Data from these three analyses were crossed, taking into consideration the different viewpoints those of the researcher and those of the users. Most importantly, this work tried to verify the contribution of urban revitalization project to the improvement of the quality of urban areas.
92

Influence of Underlying Random Walk Types in Population Models on Resulting Social Network Types and Epidemiological Dynamics

Kolgushev, Oleg 12 1900 (has links)
Epidemiologists rely on human interaction networks for determining states and dynamics of disease propagations in populations. However, such networks are empirical snapshots of the past. It will greatly benefit if human interaction networks are statistically predicted and dynamically created while an epidemic is in progress. We develop an application framework for the generation of human interaction networks and running epidemiological processes utilizing research on human mobility patterns and agent-based modeling. The interaction networks are dynamically constructed by incorporating different types of Random Walks and human rules of engagements. We explore the characteristics of the created network and compare them with the known theoretical and empirical graphs. The dependencies of epidemic dynamics and their outcomes on patterns and parameters of human motion and motives are encountered and presented through this research. This work specifically describes how the types and parameters of random walks define properties of generated graphs. We show that some configurations of the system of agents in random walk can produce network topologies with properties similar to small-world networks. Our goal is to find sets of mobility patterns that lead to empirical-like networks. The possibility of phase transitions in the graphs due to changes in the parameterization of agent walks is the focus of this research as this knowledge can lead to the possibility of disruptions to disease diffusions in populations. This research shall facilitate work of public health researchers to predict the magnitude of an epidemic and estimate resources required for mitigation.
93

Passeios aleatórios clássicos e quânticos em tapetes de Sierpinski

Souza, Daniel Gaspar Gonçalves de 20 May 2014 (has links)
Made available in DSpace on 2015-03-04T18:58:01Z (GMT). No. of bitstreams: 1 daniel_msc_final.pdf: 1791948 bytes, checksum: 1e3d1d81251eb6cff151799519eef3f9 (MD5) Previous issue date: 2014-06-23 / Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior / Classical random walks and quantum walks are studied in a whole variety of graphs in order to obtain some of its physical properties. In this work we analyze these walks over the SierpiŃski Carpet, obtaining two physical quantities: the standard deviation and the mixing time. Using simulations and fitting the points obtained over a curve, we found analytical expressions to describe the behaviour of both the standard deviation and the mixing time. When studying the quantum walk we used the QWalk software to run the simulations and generate statistics. We compare the results presenting the advantages and disadvantages of the quantum walk over the classical random one. / Passeios aleatorios classicos e passeios quanticos sao estudados em diversos grafos com o objetivo de se obter suas propriedades fisicas. Neste trabalho analisamos estes passeios no Tapete de Sierpinski com o foco em duas grandezas fisicas: o desvio padrao e o tempo de mistura. Atraves de simulacoes e usando regressao dos pontos sobre uma curva, encontramos expressoes analiticas para descrever o comportamento do desvio padrao e do tempo de mistura. No caso quantico usamos o programa QWalk para fazer as simulacoes e gerar as estatisticas. Comparamos os resultados apresentando as vantagens e desvantagens do passeio quantico sobre o classico.
94

Um novo simulador de alta performance de caminhadas / A new high performance simulation of quantum walks

Leão, Aaron Bruno 04 November 2015 (has links)
Submitted by Maria Cristina (library@lncc.br) on 2015-11-25T13:28:47Z No. of bitstreams: 1 dissertacao-aaron.pdf: 1893812 bytes, checksum: f036c76c3f4c1ba338a4e1075106ced6 (MD5) / Approved for entry into archive by Maria Cristina (library@lncc.br) on 2015-11-25T13:29:04Z (GMT) No. of bitstreams: 1 dissertacao-aaron.pdf: 1893812 bytes, checksum: f036c76c3f4c1ba338a4e1075106ced6 (MD5) / Made available in DSpace on 2015-11-25T13:29:13Z (GMT). No. of bitstreams: 1 dissertacao-aaron.pdf: 1893812 bytes, checksum: f036c76c3f4c1ba338a4e1075106ced6 (MD5) Previous issue date: 2015-11-04 / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / The development of quantum algorithms is not a easy task. Elements such as entanglement and quantum paralelism, intrinsics to quantum computation, difficult this task. Quantum walks are crucial tools for development of algorithms, mainly search algorithms. There are many types of quantum walks: with coin toss, Szegedy's, using tessellation (grouping of vertices) and the continuous-time quantum walk. To extract statistics data of a quantum walk, we need to perform its simulation. In this work, we develped the simulator Hiperwalk, a new simulator of quantum walks in graphs of one and two dimension for the quantum walk with a coin toss and coinless using tessellation. The Hiperwalk allows the user to perform simulations of quantum walks in graphs using high performance computing (HPC), even though the user does not knowing parallel programming. The user can employ the parallel devices such as CPU, GPGPU and accelerators cards to speedup the overall process of the walk. / O desenvolvimento de algoritmos quânticos não é uma tarefa trivial. Elementos como emaranhamento e paralelismo quântico, intrínsecos à computação quântica, dificultam esta tarefa. As caminhadas quânticas são ferramentas cruciais para o desenvolvimento de algoritmos, principalmente algoritmos de busca. Existem na literatura vários tipos de caminhadas: com lançamento de moeda, de Szegedy, utilizando tesselagem (agrupamento de vértices) e a caminhada a tempo contínuo. Para extrair dados estatísticos de uma determinada caminhada quântica, necessitamos fazer sua simulação. Neste trabalho, desenvolvemos o simulador Hiperwalk, um novo simulador de caminhadas quânticas, em grafos de uma e duas dimensões para as caminhadas com moeda e sem moeda utilizando tesselagem. O Hiperwalk permite ao usuário efetuar simulações de caminhadas quânticas em grafos utilizando processamento de alto desempenho, mesmo que o usuário não saiba programação paralela. O usuário pode empregar os dispositivos de paralelismo como CPU, GPGPU e co-processadores para acelerar o processo geral da caminhada.
95

Em busca da autonomia da mulher: análise do contrato de comunicação da Marcha das Vadias

Ferreira, Juliana Cristina da Silva 19 June 2017 (has links)
Submitted by Filipe dos Santos (fsantos@pucsp.br) on 2017-07-11T12:44:27Z No. of bitstreams: 1 Juliana Cristina da Silva Ferreira.pdf: 3009287 bytes, checksum: 6ef0bd5196d04d71e8d0dac3bb17b3b8 (MD5) / Made available in DSpace on 2017-07-11T12:44:27Z (GMT). No. of bitstreams: 1 Juliana Cristina da Silva Ferreira.pdf: 3009287 bytes, checksum: 6ef0bd5196d04d71e8d0dac3bb17b3b8 (MD5) Previous issue date: 2017-06-19 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / This research examines how the Slut Walks enunciator constituted her communication contract from nodal point “female body anatomy”, thereby also analyses the discursive displacement undertaken by the enunciator when antagonizing the hegemonic discourse of male domination. The research corpus is composed by Facebook page analysis “Marcha das Vadias Sampa” from the period of May 2012 to July 2016, beyond direct observation of “V edição da Marcha das Vadias” and more activities performed by Coletiva Marcha das Vadias Sampa in 2015. This research is inserted in two research universes: feminism and discourse. Hence, in the first chapter we dedicated in understand how the Slut Walks built itself as XXI century feminist movement with contribution of theoreticians Michelle Perrot and Carla Garcia. In the next chapter, we present the Slut Walks as discursive identity in a social field of linguistic disputes with theoretical reference of Ernesto Laclau and Chantal Mouffe. In sequence, we analyse the walk calling from contributions of José Luiz Aidar Prado. Finally, in the last chapter we dedicate in the comprehension of Slut Walks demobilization in São Paulo city, and the way that the proposed discourse from the movement is denied and accepted by other feminist discursive entities / Esta pesquisa examina como a enunciadora Marcha das “Vadias” constituiu o seu contrato de comunicação a partir do ponto nodal “autonomia do corpo da mulher”, assim como analisa o deslocamento discursivo empreendido pela enunciadora ao antagonizar o discurso hegemônico de dominação masculina. O corpus da pesquisa é composto pela análise da página do Facebook “Marcha das Vadias Sampa” no período entre maio de 2012 e julho de 2016, além da observação direta da V edição da Marcha das Vadias e demais atividades realizadas pela Coletiva Marcha das Vadias Sampa no ano de 2015. Esta pesquisa está inserida em dois universos de pesquisa: feminismo e discurso. Dessa forma, no primeiro capítulo nos dedicamos a entender como a Marcha das “Vadias” se construiu como movimento feminista do século XXI, com as contribuições das teóricas Michelle Perrot e Carla Garcia. No capítulo seguinte apresentamos a Marcha das “Vadias” como uma identidade discursiva em um campo social de disputas linguísticas com o referencial teórico de Ernesto Laclau e Chantal Mouffe. Em sequência, analisamos as convocações da marcha, a partir das contribuições de José Luiz Aidar Prado. Por fim, no último capítulo nos dedicamos à compreensão da desmobilização da Marcha das “Vadias”, na cidade de São Paulo, e da forma com que o discurso proposto pelo movimento é negado e aceito por outras identidades discursivas feministas
96

Connectivity Properties of Archimedean and Laves Lattices

Parviainen, Robert January 2004 (has links)
<p>An Archimedean lattice is a graph of a regular tiling of the plane, such that all corners are equivalent. A tiling is regular if all tiles are regular polygons: equilateral triangles, squares, et cetera. There exist exactly 11 Archimedean lattices. Being planar graphs, the Archimedean lattices have duals, 3 of which are Archimedean, the other 8 are called Laves lattices.</p><p>In the thesis, three measures of connectivity of these 19 graphs are studied: the connective constant for self-avoiding walks, and bond and site percolation critical probabilities. The connective constant measures connectivity by the number of walks in which all visited vertices are unique. The critical probabilities quantify the proportion of edges or vertices that can be removed, so that the produced subgraph has a large connected component.</p><p>A common issue for these measures is that they, although intensely studied by both mathematicians and scientists from other fields, have been calculated only for very few graphs. With the goal of comparing the induced orders of the Archimedean and Laves lattices under the three measures, the thesis gives improved bounds and estimates for many graphs. </p><p>A large part of the thesis focuses on the problem of deciding whether a given graph is a subgraph of another graph. This, surprisingly difficult problem, is considered for the set of Archimedean and Laves lattices, and for the set of matching Archimedean and Laves lattices.</p>
97

Discrete-time quantum walks via interchange framework and memory in quantum evolution

Dimcovic, Zlatko 14 June 2012 (has links)
One of the newer and rapidly developing approaches in quantum computing is based on "quantum walks," which are quantum processes on discrete space that evolve in either discrete or continuous time and are characterized by mixing of components at each step. The idea emerged in analogy with the classical random walks and stochastic techniques, but these unitary processes are very different even as they have intriguing similarities. This thesis is concerned with study of discrete-time quantum walks. The original motivation from classical Markov chains required for discrete-time quantum walks that one adds an auxiliary Hilbert space, unrelated to the one in which the system evolves, in order to be able to mix components in that space and then take the evolution steps accordingly (based on the state in that space). This additional, "coin," space is very often an internal degree of freedom like spin. We have introduced a general framework for construction of discrete-time quantum walks in a close analogy with the classical random walks with memory that is rather different from the standard "coin" approach. In this method there is no need to bring in a different degree of freedom, while the full state of the system is still described in the direct product of spaces (of states). The state can be thought of as an arrow pointing from the previous to the current site in the evolution, representing the one-step memory. The next step is then controlled by a single local operator assigned to each site in the space, acting quite like a scattering operator. This allows us to probe and solve some problems of interest that have not had successful approaches with "coined" walks. We construct and solve a walk on the binary tree, a structure of great interest but until our result without an explicit discrete time quantum walk, due to difficulties in managing coin spaces necessary in the standard approach. Beyond algorithmic interests, the model based on memory allows one to explore effects of history on the quantum evolution and the subtle emergence of classical features as "memory" is explicitly kept for additional steps. We construct and solve a walk with an additional correlation step, finding interesting new features. On the other hand, the fact that the evolution is driven entirely by a local operator, not involving additional spaces, enables us to choose the Fourier transform as an operator completely controlling the evolution. This in turn allows us to combine the quantum walk approach with Fourier transform based techniques, something decidedly not possible in classical computational physics. We are developing a formalism for building networks manageable by walks constructed with this framework, based on the surprising efficiency of our framework in discovering internals of a simple network that we so far solved. Finally, in line with our expectation that the field of quantum walks can take cues from the rich history of development of the classical stochastic techniques, we establish starting points for the work on non-Abelian quantum walks, with a particular quantum walk analog of the classical "card shuffling," the walk on the permutation group. In summary, this thesis presents a new framework for construction of discrete time quantum walks, employing and exploring memoried nature of unitary evolution. It is applied to fully solving the problems of: A walk on the binary tree and exploration of the quantum-to-classical transition with increased correlation length (history). It is then used for simple network discovery, and to lay the groundwork for analysis of complex networks, based on combined power of efficient exploration of the Hilbert space (as a walk mixing components) and Fourier transformation (since we can choose this for the evolution operator). We hope to establish this as a general technique as its power would be unmatched by any approaches available in the classical computing. We also looked at the promising and challenging prospect of walks on non-Abelian structures by setting up the problem of "quantum card shuffling," a quantum walk on the permutation group. Relation to other work is thoroughly discussed throughout, along with examination of the context of our work and overviews of our current and future work. / Graduation date: 2012
98

Monte Carlo random walk simulation as a complement to experimental and theoretical approaches : application to mass transfer in fish muscle tissue

Almonacid-Merino, Sergio Felipe 15 July 2005 (has links)
Mass transfer processes in food systems, such as solute infusion, are poorly understood because of their complex nature. Food systems contain porous matrices and a variety of continuous phases within cellular tissues. Mass transfer processes are generally not pure diffusion: often convection, binding and obstructing diffusion will occur. Monte Carlo (MC) simulation has been increasingly used in life science and engineering to elucidate molecular transport in biological systems. However, there are few articles available discussing MC simulation in food processing, especially mass transfer. The main goal of this study was to show the inherent simplicity of the MC approach and its potential when combined with traditional experimental and theoretical approaches to better describe and understand mass transfer processes. A basic framework for MC random walk - simulation applied to a diffusion problem - is developed in this project. Infusion of two sizes of dextran macromolecules in fish muscle cells is used to apply the MC framework in combination with Fluorescence Recovery After Photobleaching experiments. Effective diffusivity coefficients within cells, considering the degree of obstruction due to the myofibrilar matrix, are assessed. Then, the results are used as input in a mathematical model that was developed for theoretical simulation of mass transfer in the multi-cellular tissue. Diffusivity values obtained by the MC framework had an SD of ±0.02 [µm²/s] around the true value of 0.25 [µm²/s]. MC results for degree of obstruction were 0.29 and 0.34 for dextran FD1OS and FD2OS, respectively, and the Devalues were 23.7 and 11.2 [µm2/s]. The statistical error in the estimation of D was estimated to be [22.8-24.6] and [9.7-12.7] (95% CI), where average experimental values of 24.3 [µm²/s] for FD1OS and 11.4 [µm²/s] for FD2OS were captured by the respective interval. The theoretical model showed a significant influence of the cell membrane characteristics and tissue porosity in both the degree of solute penetration and the solute distribution between intra- and extra-cellular space. The combined approach was successfully applied to a diffusion problem. Overall, it is expected that the present work will contribute towards the application of MC simulation in the field of Food Science and Engineering. / Graduation date: 2006
99

Connectivity Properties of Archimedean and Laves Lattices

Parviainen, Robert January 2004 (has links)
An Archimedean lattice is a graph of a regular tiling of the plane, such that all corners are equivalent. A tiling is regular if all tiles are regular polygons: equilateral triangles, squares, et cetera. There exist exactly 11 Archimedean lattices. Being planar graphs, the Archimedean lattices have duals, 3 of which are Archimedean, the other 8 are called Laves lattices. In the thesis, three measures of connectivity of these 19 graphs are studied: the connective constant for self-avoiding walks, and bond and site percolation critical probabilities. The connective constant measures connectivity by the number of walks in which all visited vertices are unique. The critical probabilities quantify the proportion of edges or vertices that can be removed, so that the produced subgraph has a large connected component. A common issue for these measures is that they, although intensely studied by both mathematicians and scientists from other fields, have been calculated only for very few graphs. With the goal of comparing the induced orders of the Archimedean and Laves lattices under the three measures, the thesis gives improved bounds and estimates for many graphs. A large part of the thesis focuses on the problem of deciding whether a given graph is a subgraph of another graph. This, surprisingly difficult problem, is considered for the set of Archimedean and Laves lattices, and for the set of matching Archimedean and Laves lattices.
100

Algebraic Aspects of Multi-Particle Quantum Walks

Smith, Jamie January 2012 (has links)
A continuous time quantum walk consists of a particle moving among the vertices of a graph G. Its movement is governed by the structure of the graph. More formally, the adjacency matrix A is the Hamiltonian that determines the movement of our particle. Quantum walks have found a number of algorithmic applications, including unstructured search, element distinctness and Boolean formula evaluation. We will examine the properties of periodicity and state transfer. In particular, we will prove a result of the author along with Godsil, Kirkland and Severini, which states that pretty good state transfer occurs in a path of length n if and only if the n+1 is a power of two, a prime, or twice a prime. We will then examine the property of strong cospectrality, a necessary condition for pretty good state transfer from u to v. We will then consider quantum walks involving more than one particle. In addition to moving around the graph, these particles interact when they encounter one another. Varying the nature of the interaction term gives rise to a range of different behaviours. We will introduce two graph invariants, one using a continuous-time multi-particle quantum walk, and the other using a discrete-time quantum walk. Using cellular algebras, we will prove several results which characterize the strength of these two graph invariants. Let A be an association scheme of n × n matrices. Then, any element of A can act on the space of n × n matrices by left multiplication, right multiplication, and Schur multiplication. The set containing these three linear mappings for all elements of A generates an algebra. This is an example of a Jaeger algebra. Although these algebras were initially developed by Francois Jaeger in the context of spin models and knot invariants, they prove to be useful in describing multi-particle walks as well. We will focus on triply-regular association schemes, proving several new results regarding the representation of their Jaeger algebras. As an example, we present the simple modules of a Jaeger algebra for the 4-cube.

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