Orientador: Rubens Caram Junior / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Mecanica / Made available in DSpace on 2018-08-14T01:19:58Z (GMT). No. of bitstreams: 1 Contieri_RodrigoJose_M.pdf: 6106126 bytes, checksum: c0a763660f171b211110a4237cfd34db (MD5) Previous issue date: 2009 / Resumo: A aplicação de tratamentos térmicos de recozimento a materiais metálicos encruados pode resultar em fenômenos de recuperação, de recristalização e de crescimento de grãos. Tal tipo de tratamento térmico resulta na transformação da microestrutura e, portanto, das propriedades físicas e mecânicas do material. O objetivo deste trabalho é determinar parâmetros característicos do processo de recristalização e de crescimento de grãos do titânio comercialmente puro (Ti C.P.) por meio do desenvolvimento e aplicação de um modelo teórico baseado no algoritmo autômatos celulares e em experimentos. Esse modelo teórico considera a redução da energia interfacial nos contornos de grão a cada intervalo de tempo como força motriz do processo, assim como a influência de uma barreira de potencial. Objetivando validar os resultados teóricos obtidos e também obter informações necessárias à simulação, foram executados experimentos associados à laminação, a tratamentos térmicos e à caracterização de amostras de Ti C.P. Os resultados obtidos mostram que o modelo concebido é capaz de simular processos de recristalização e de crescimento de grãos. Observou-se a dependência da cinética de crescimento em relação à energia de ativação, temperatura e energia interfacial nos contornos. Por outro lado, concluiu-se que a recristalização do Ti C.P. laminado à temperatura ambiente pode ser investigada através de análises quantitativas de calorimetria diferencial de varredura (DSC) e de microdureza. Finalmente, informações obtidas da aplicação do modelo teórico exibem boa concordância com dados obtidos experimentalmente e com outros disponíveis na literatura / Abstract: Application of annealing heat treatments to strain hardened metallic materials may give rise to recuperation, recrystallization and grain growth phenomena. This heat treatment leads to microstructure transformation and hence, changes in physical and mechanical properties. The aim of this work is to determine parameters of recrystallization and grain growth processes of commercially pure titanium (C.P. Ti) by means of the development and application of a theoretical model based on Cellular Automata algorithm as well as on experiments. This model considers the decrease in the interfacial energy at grain boundaries every time step as the process driving force. In addition, it takes into account the influence of potential barrier. To validate theoretical results as well as to obtain essential information for the simulation, experiments related to rolling, heat treatments and characterization of C.P. Ti samples were carried out. The results obtained show the developed model is able to simulate recrystallization and grain growth processes. It was observed the growth kinetic depends on activation energy, temperature and interfacial energy at the boundaries. Also, it was concluded that recrystallization of the room temperature rolled C.P. Ti may be investigated by using results of differential scanning calorimetry and microhardness. Finally, information obtained by using the theoretical model well agrees with data experimentally obtained and with other available in literature / Mestrado / Materiais e Processos de Fabricação / Mestre em Engenharia Mecânica

CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / A evacuaÃÃo de locais aglomerados, sujeita a restriÃÃes fÃsicas e temporais, à uma questÃo que merece atenÃÃo especial. Se uma multidÃo falha ao escapar em tempo de um ambiente perigoso, por tomar um caminho errado ou por escolher uma saÃda ruim, hà um grande risco de lesÃes e morte. SimulaÃÃes de evacuaÃÃo de multidÃo sÃo muito importantes para tentar minimizar esses tipos de riscos. PorÃm, tentar simular situaÃÃes de emergÃncia em ambientes reais ou à muito caro ou mesmo impossÃvel. Portanto, a simulaÃÃo da evacuaÃÃo de multidÃo por computador à uma alternativa melhor. Os estÃdios de futebol sÃo exemplos de ambientes que podem apresentar risco para as vidas das pessoas no caso de uma evacuaÃÃo de emergÃncia. O objetivo principal deste trabalho à ganhar compreensÃo sobre os aspectos inerentes ao problema de simulaÃÃo de evacuaÃÃo de emergÃncia. Para isso, foi proposto um novo modelo para evacuaÃÃo de multidÃo baseado no modelo de autÃmatos celulares. A fim de avaliar o modelo proposto, testes em diferentes situaÃÃes foram realizados. Foi mostrado que o modelo proposto à capaz de simular a evacuaÃÃo em ambientes complexos de uma forma eficiente. / The evacuation from crowded places, subjected to physical and temporal restrictions, is a matter that deserves special attention. If a crowd fails to escape in time from a hazardous environment, by taking a wrong way or by selecting a bad exit, there is great risk of injuries and death. Simulations of crowd evacuation are very important to try to minimize those types of risk. However, trying to simulate emergency situations in real environments is either very expensive or even impossible. Therefore, computer simulation of crowd evacuation is a better alternative. The soccer stadiums are examples of environments that may present risk to people's lives in case of emergency evacuation. The main objective of this work is to gain understanding of the inherent aspects of the problem of emergency evacuation simulation, and to investigate the dynamics of the evacuation behavior of crowds during an emergency evacuation from a soccer stadium. For this, it was proposed a new model for crowd evacuation based on the cellular automata model. In order to validate the proposed model, tests in different situations were performed. It was shown that the proposed model is able to simulate the evacuation of complex environments in an efficient way.

Made available in DSpace on 2016-03-15T19:38:06Z (GMT). No. of bitstreams: 1 Paulo Sergio Germano da Silva.pdf: 409690 bytes, checksum: d0a755bc0651655440f8954300bd67e8 (MD5) Previous issue date: 2007-09-17 / Fundo Mackenzie de Pesquisa / Problem solving through computation based on cellular automata rules remains a challenging subject, the scarcity of knowledge in the area. Among several problems reported in the literature, the parity problem has generated significant interest, its aim being to ascertain the parity of a quantity of 1s in a binary string, input as an initial configuration to a binary, one-dimensional, cellular automaton. Although a classic problem, no rule able to solve this problem has been found to date. Indeed, it remains uncertain as to whether such a solution exists. In this context, this work presents the results of evolutionary searches for sound rules of one-dimensional, cellular automata of radius 3, in the parity problem. The main focus of the research was to verify the effect of varying the strategies used to generate initial test configuration samples, which implied different ways of evaluating the candidate rules. Such an approach extends the work in [Oliveira e Vaiano, 2005] in the direction of better understanding as well as trying to reproduce some of the results in [Wolz e de Oliveira, 2007], where rules with excellent performance at odd-sised lattices were reported, as well as rules with good performance at even-sised lengths, even though the latter showed lack of robustness. In spite of testing a range of approaches, none led to good rules for the problem, leading to the conclusion that the excellent results obtained in [Wolz e de Oliveira, 2007] were due to the other concepts used therein, distinct from those evaluated in the present study. / A obtenção de soluções de problemas através da computação implícita a regras de autômatos celulares permanece um assunto desafiador, pelo pouco que ainda se conhece a respeito. Entre vários problemas abordados na literatura, um que tem despertado interesse é o problema da paridade, em que a meta é determinar a paridade da quantidade de 1s de uma cadeia binária fornecida como configuração inicial a um autômato celular unidimensional binário. Apesar de clássico, ainda não se tem registro de uma regra capaz de resolver o problema e, de fato, nem se sabe se essa solução existe. Nesse contexto, apresentam-se aqui os resultados experimentais de buscas evolutivas realizadas para encontrar boas regras de autômatos celulares unidimensionais binários de raio 3, no problema da paridade. O foco principal da pesquisa foi verificar o efeito de se variar as estratégias de geração das amostras de configurações iniciais de teste, o que se traduz em diferentes formas de avaliação das regras candidatas. Tal enfoque expande os trabalhos de [de Oliveira e Vaiano, 2005], caminhando na direção de melhor compreender e reproduzir alguns dos resultados obtidos em [Wolz e de Oliveira, 2007], em que regras de excelente desempenho foram achadas para reticulados de comprimento ímpar, bem como regras de bom desempenho, apesar de não robustas, para alguns comprimentos pares de reticulados. A despeito das várias abordagens testadas, nenhuma delas conduziu a boas regras no problema em questão, fazendo crer que a qualidade conseguida em [Wolz e de Oliveira, 2007] deve-se, portanto, aos outros conceitos lá empregados, distintos dos aqui avaliados.

O presente trabalho teve como foco o desenvolvimento de um software para a simulação de processos de microfabricação em substrato e de microfabricação em superfície baseado em autômatos celulares, o simMEMS. Além disso, visando a futura incorporação de ferramentas para análise das estruturas geradas pelo programa, um módulo com funcionalidades básicas para a análise mecânica de estruturas também foi desenvolvido. No que tange à microfabricação em superfície, o software desenvolvido permite simular a corrosão anisotrópica úmida do Si em KOH e deep reactive ion etching (DRIE). O simulador de corrosão úmida utiliza um autômato celular conhecido como BCA. O simulador de DRIE usa um autômato próprio. Para a simulação dos processos de microfabricação em superfície o software fornece quatro processos: deposição de filmes, corrosão de filmes, fotolitografia e planarização. Para corrosão e deposição de filmes, diversos autômatos celulares da literatura foram analisados e os resultados dessas análises é aqui apresentado. Todos os simuladores, tanto de microfabricação em superfície como em substrato, podem ser utilizados em conjunto. Isso torna o software bastante útil e capaz de simular a fabricação de um grande número de dispositivos. / The main goal of this project is the development of a software capable of simulating both surface and bulk micromachining based on a cellular automata approach. This software has been called simMEMS. In order to enable future versions of the software to also be able to analyze the structures created by the software, a module capable of running a mechanical analysis through the finite element method is also developed. simMEMS allows the user to simulate two bulk micromachining processes: wet anisotropic KOH etching and deep reactive ion etching DRIE. The wet etching simulator uses a cellular automaton known as BCA. The DRIE simulator uses an automaton developed during this project. The surface micromachining simulator allows the user to simulate four types of processes: photolithography, film deposition, film etching and substrate planarization. Several automata for the deposition and etching of films are studied and the results of this study are presented here. All processes, be they for surface or bulk micromachining, can be used on the same substrate to simulate the entire fabrication process for a large array of devices. This makes simMEMS a very useful software.

Procedurell generering är ett område som vuxit mycket på de senaste åren men som också är ett gammalt område. Kända koncept inom detta område är kart- och terränggenerering. Koncepten används för att skapa både verklighetstrolig terräng och för att skapa spelkartor för spelaren att utforska.Detta arbete använder sig av procedurell generering för att undersöka skillnaden mellan två kända metoder; Voronoidiagram och Cellular Automata vid skapandet av en provinskarta. Tre kartor från varje metod evalueras genom att importeras i spelet Crusader Kings 2 och sedan spelas med hjälp av spelets artificiella intelligens. Kartorna evalueras genom att titta på tre olika faktorer för hur intressant kartan är och prestandan för att skapa en karta. Resultatet visar att det både är lite skillnad mellan de två metoderna som jämförts men också att det är väldigt liten skillnad mot standardkartan. Prestandamässigt är det dock Voronoidiagrammet som är överlägset med ungefär dubbel tidseffektivitet jämfört med Cellular Automata.

Les modèles numériques sont un outil complémentaire pour la prédiction de la corrosion. L'objectif de cette thèse est de développer un modèle de corrosion reposant sur la méthode des automates cellulaires pour l'étude de l'évolution morphologique des surfaces, ainsi que de la cinétique de corrosion. Le modèle développé couple les demi-réactions électrochimiques d'oxydation et de réduction. Au niveau cinétique, la simulation par automates cellulaires peut alors reproduire les courbes intensité-potentiel d'une réaction redox sur électrode inerte. L'échelle spatio-temporelle choisie décrit des phénomènes de corrosion à l'échelle mésoscopique, niveau intermédiaire par rapport aux approches habituelles. Dans notre modèle, les probabilités rendent compte de la nature stochastique des réactions anodiques et cathodiques. Cette étude nous a permis de décrire l'évolution de la morphologie de la corrosion dans différents contextes: corrosion généralisée, corrosion par piqûre et corrosion en milieu confiné. Deux régimes de corrosion ont été observés: un régime de corrosion uniforme dans lequel les demi-réactions sont distribuées de manière homogène suivi par un régime de corrosion localisée, caractérisé par une séparation spatiale des zones cathodiques et anodiques. / Numerical modelling is complementary tool for corrosion prediction. The objective of this work is to develop a corrosion model by means of a probabilistic cellular automata approach at a mesoscopic scale. In this work, we study the morphological evolution and kinetics of corrosion. This model couples electrochemical oxydation and reduction reactions. Regarding kinetics, cellular automata models are able to describe current as a function of the applied potential for a redox reaction on an inert electrode. The inclusion of probabilities allows the description of the stochastic nature of anodic and cathodic reactions. Corrosion morphology has been studied in different context: generalised corrosion, pitting corrosion and corrosion in an occluded environment. A general tendency of two regimes is found. A first regime of uniform corrosion where the anodic and cathodic reactions occur homogeneously over the surface. A second regime of localized corrosion when there is a spatial separation of anodic and cathodic zones, with an increase of anodic reaction rate.

Pseudorandom sequences have many applications in fields such as wireless communication, cryptography and built-in self test of integrated circuits. Maximal length sequences (m-sequences) are commonly employed pseudorandom sequences because they have ideal randomness properties like balance, run and autocorrelation. However, the linear complexity of m-sequences is poor. This thesis considers the use of one-dimensional Cellular Automata (CA) to generate pseudorandom sequences that have high linear complexity and good randomness. The properties of these sequences are compared with those of the corresponding m-sequences to determine their suitability. / Graduate

The need for more inclusive and integrated cities has resulted in a paradigm shift in the South African transport and land use policy environment where transport and land use planning are viewed as a continuum as opposed to isolated planning aspects. Issues such as residential segregation, social exclusion, spatial inefficiencies, inequality, residential informality, marginalisation of the low-income cohort continue to form part of the current planning discourse. While policy acknowledges the need to redress these issues, the urban spatial patterns in South African cities continue to trace the historical planning trajectory. Recently, congestion has become an issue in some of South Africa’s cities with Johannesburg and Cape Town appearing in the list of the top hundred most congested cities in the world. It is thus essential to understand how South African cities can address urban accessibility and mobility issues along with redressing apartheid spatial planning to attain sustainable cities that allow for inclusivity of all population groups. Like most South African cities, Cape Town is a relic of apartheid planning where the urban spatial patterns reinforce social exclusion among other issues. Urban and transport planning in Cape Town focuses on addressing issues of spatial inefficiencies, social exclusion, congestion due to rapid motorisation and the proliferation of informal settlements. It is against this backdrop that the central concern of this research is to understand urban dynamics linked to the spatiotemporal interaction of transport and land use in Cape Town to aid in the formulation of proactive urban policies. There is compelling evidence in the literature that dynamic integrated land use transport models provide an avenue through which the urban change process can be understood to aid in the development of adaptive land use and transport strategies. METRONAMICA, a dynamic land use transport model, is applied in this research to simulate and understand land use and transport change in Cape Town. A sequential stage-wise procedure was implemented to calibrate the model for the period 1995- 2005 and an independent validation was carried out from 2005 to 2010 to evaluate the model. Kappa statistic and its associated variants were applied to assess the ability of the land use model block to reproduce land use patterns while the EMME model and previous transport studies for Cape Town were used to evaluate the transport model. The results from the calibration and validation exercise show that the model can reproduce historical land use and transport patterns. The integration of the transport and land use model through accessibility improved the Kappa Simulation and Fuzzy Kappa Simulation. This showed that the model explained urban change better when land use and transport interacted compared to an independent land use model. This shows that accessibility can be employed in the Cape Town context to enhance the understanding of the urban change process. In addition to the Kappa statistics, the fractal dimension which measures the landscape complexity was used to assess the predictive accuracy of the model. The model performance revealed that the landscape patterns simulated by the model resemble observed land use patterns signifying a good calibration of the model. The calibrated land use transport model for the Cape Town Metropolitan region (CTMRLUT) was applied for policy scenarios. Three scenarios were simulated, specifically the business as usual (BAU), redressing social exclusion and the potential for in situ upgrading of informal settlements. The study found that intensive land use development along the Metro South East Integration Zone (MSEIZ) was linked to a reduction in commuting distances to economic activities which is in contrast to the BAU scenario. While these scenarios looked at the urban spatial patterns, the effect of land use patterns on congestion was also explored. The findings from the scenario simulations suggest that despite the reduction in distance to economic centres, the congestion condition in Cape Town will continue to deteriorate. Further, the findings indicate that interventions that only target land use developments are not sufficient to address congestion issues in Cape Town. Instead, to address the congestion problem in Cape Town, mixed land use and compact growth strategies need to be complemented with travel demand management strategies that target private car usage and intensive investment in transport infrastructure, especially rail, to facilitate the use of alternative modes. With regards to informal settlements, the study found that in situ upgrading could be a viable option to tackle some informal settlements. However, for proper inclusionary informal settlement policy, an approach that resonates with contextual realities would be more suitable to assess the viability of in situ upgrading based on the location of informal settlements relative to centres of economic activities. Additionally, the study revealed that instead of informal settlements locating as stand-alone settlements, some of them located adjacent to low-income housing which might be indicative of a growth in backyard shacks which is an existing housing trend in some lowincome suburbs in Cape Town. While this research has shown that integrating land use and transport in policy is potentially useful in solving urban issues, it has also revealed the value of urban modelling as a platform on which to assess the potential impacts of policies before their implementation. This is a strong case for the utilisation of decision support tools in land use and transport planning in contemporary South African cities.

This paper presents the design of a reconfigurable asynchronous unit, called the pulsed quad-cell (PQ-cell), for conformal computing. The conformal computing vision is to create computational materials that can conform to the physical and computational needs of an application. PQ-cells, like cellular automata, are assembled into arrays with nearest neighbor communication and are capable of general computation. They operate asynchronously to minimize power consumption and to allow sealing without the limitations imposed by a global clock. Cell operations are stimulated by pulses which use two wires to encode a data bit. Cells are individually reconfirgurable to perform logic, move and store information, and coordinate parallel activity. The PQ-cell design targets a 0.25 μm CMOS technology. Simulation results show that a PQ-cell, when pulsed at 1.3 GHz, consumes 16.9 pJ per operation. Examples of self-timed multi-cell structures include a 98 MHz ring oscillator and a 385 MHz pipeline.

This master's thesis deals with modelling and simulation of physical phenomena by cellular automata. The basic methods which model physical phenomena is enumerated and descibed in this thesis. One of the important part of this thesis is a set of demonstration models. Each model is focused on one selected area of physical phenomena. All models are described by transtition rules and the procedure of derivation of these rules is also presented here. There rules were used in implemented models.  Another part of this thesis contains of a simulation application for these models. The real application had been implemented in accord with this design and it has been used to perform the simulation experiments with exemplary models. Results of the simulation experiments are discussed in conclusion of this thesis. One exemplary model had also been adapted for parallel processing. The performances on a computer with different count of working processors were measured and are also discussed in the conclusion of this thesis