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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.
221

Design, Synthesis and Test of Reversible Circuits for Emerging Nanotechnologies

Thapliyal, Himanshu 01 January 2011 (has links)
Reversible circuits are similar to conventional logic circuits except that they are built from reversible gates. In reversible gates, there is a unique, one-to-one mapping between the inputs and outputs, not the case with conventional logic. Also, reversible gates require constant ancilla inputs for reconfiguration of gate functions and garbage outputs that help in keeping reversibility. Reversible circuits hold promise in futuristic computing technologies like quantum computing, quantum dot cellular automata, DNA computing, optical computing, etc. Thus, it is important to minimize parameters such as ancilla and garbage bits, quantum cost and delay in the design of reversible circuits. The first contribution of this dissertation is the design of a new reversible gate namely the TR gate (Thapliyal-Ranganathan) which has the unique structure that makes it ideal for the realization of arithmetic circuits such as adders, subtractors and comparators, efficient in terms of the parameters such as ancilla and garbage bits, quantum cost and delay. The second contribution is the development of design methodologies and a synthesis framework to synthesize reversible data path functional units, such as binary and BCD adders, subtractors, adder-subtractors and binary comparators. The objective behind the proposed design methodologies is to synthesize arithmetic and logic functional units optimizing key metrics such as ancilla inputs, garbage outputs, quantum cost and delay. A library of reversible gates such as the Fredkin gate, the Toffoli gate, the TR gate, etc. was developed by coding in Verilog for use during synthesis. The third contribution of this dissertation is the set of methodologies for the design of reversible sequential circuits such as reversible latches, flip-flops and shift registers. The reversible designs of asynchronous set/reset D latch and the D flip-flop are attempted for the first time. It is shown that the designs are optimal in terms of number of garbage outputs while exploring the best possible values for quantum cost and delay. The other important contributions of this dissertation are the applications of reversible logic as well as a special class of reversible logic called conservative reversible logic towards concurrent (online) and offline testing of single as well as multiple faults in traditional and reversible nanoscale VLSI circuits, based on emerging nanotechnologies such as QCA, quantum computing, etc. Nanoelectronic devices tend to have high permanent and transient faults and thus are susceptible to high error rates. Specific contributions include (i) concurrently testable sequential circuits for molecular QCA based on reversible logic, (ii) concurrently testable QCA-based FPGA, (iii) design of self checking conservative logic gates for QCA, (iv) concurrent multiple error detection in emerging nanotechnologies using reversible logic, (v) two-vectors, all 0s and all 1s, testable reversible sequential circuits.
222

Development Of A Micro-fabrication Process Simulator For Micro-electro-mechanical-systems(mems)

Yildirim, Alper 01 December 2005 (has links) (PDF)
ABSTRACT DEVELOPMENT OF A MICRO-FABRICATION PROCESS SIMULATOR FOR MICRO-ELECTRO-MECHANICAL SYSTEMS (MEMS) Yildirim, Alper M.S, Department of Mechanical Engineering Supervisor: Asst. Prof. Dr. Melik D&ouml / len December 2005, 140 pages The aim of this study is to devise a computer simulation tool, which will speed-up the design of Micro-Electro-Mechanical Systems by providing the results of the micro-fabrication processes in advance. Anisotropic etching along with isotropic etching of silicon wafers are to be simulated in this environment. Similarly, additive processes like doping and material deposition could be simulated by means of a Cellular Automata based algorithm along with the use of OpenGL library functions. Equipped with an integrated mask design editor, complex mask patterns can be created by the software and the results are displayed by the Cellular Automata cells based on their spatial location and plane. The resultant etched shapes are in agreement with the experimental results both qualitatively and quantitatively. Keywords: Wet Etching, Anisotropic Etching, Doping, Cellular Automata, Micro-fabrication simulation, Material Deposition, Isotropic Etching, Dry Etching, Deep Reactive Ion Etching
223

Agent behavior in peer-to-peer shared ride systems /

Wu, Yunhui. January 2007 (has links)
Thesis (M.Geom.M.)--University of Melbourne, Dept. of Geomatics, 2007. / Typescript. Includes bibliographical references (leaves 100-104).
224

Modelagem dinâmica espacial aplicada na avaliação das mudanças da cobertura da terra no entorno de dutos utilizando autômatos celulares : estudo de caso duto ORBEL /

Delaneze, Marcelo Elias. January 2011 (has links)
Orientador: Paulina Setti Riedel / Banca: Cláudia Maria de Almeida / Banca: Maria Lúcia Marques / Resumo: A obtenção de informação sobre as condições da rede dutoviária representa papel primordial na operação dos dutos, não só com o propósito de manter a eficiência operacional, mas também, para a minimização dos riscos associados a possíveis acidentes, tanto decorrentes dos processos naturais quanto de causas antrópicas relacionadas ao uso e cobertura da terra. Neste sentido, o emprego de modelos matemáticos em estudos ambientais gera importantes contribuições científicas ao planejamento ordenado de uma área, uma vez que ajudam a entender o impacto das mudanças no uso e cobertura da terra e a prever alterações futuras nos ecossistemas. A área de estudo compreende porções dos municípios de Duque de Caxias, Belford Roxo e Nova Iguaçu e tem por objetivo realizar experimentos de mudanças da cobertura da terra em médio prazo (10 anos) para a faixa de dutos ORBEL. A modelagem realizada neste trabalho foi desenvolvida no software Dinamica-EGO, utilizando como entrada mapas classificados de cobertura da terra, obtidos através de imagens do satélite Landsat 5/TM, e variáveis espaciais para explicar as mudanças ocorridas na cobertura da terra. Para a calibração do modelo, utilizou-se o método de pesos de evidência, disponível no Dinamica-EGO, primeiramente categorizando-se os mapas de variáveis contínuas e, posteriormente, calculando-se os pesos de evidência. Valores positivos favorecem determinada transição, enquanto valores negativos indicam baixa probabilidade de transição, e valores próximos a zero não exercem efeito. A validação do modelo se deu pelo método de similaridade fuzzy, com decaimento exponencial. Os resultados mostram que, para os dois períodos analisados (1987-1998 e 1998-2010), a taxa de mudança para a transição "vegetação arbórea para outros" é bem maior do que para... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Reliable information about conditions of pipeline network represents a major role in the operation of pipelines, not only in order to maintain operational efficiency, but also to minimize the risks associated with possible accidents such as rupture of the ducts due to landslides or mudslides mass block, causing damage to humans and the environment. The use of mathematical models in environmental studies allows significant scientific contributions to the physical planning of an area, since they help to understand the impact of changes in land use and land cover and predict future trends of changes in ecosystems. The study area includes portions of the municipalities of Duque de Caxias, Nova Iguaçu, and Belford Roxo and aims to carry out experiments in land-cover changes in the medium-term (10 years) within the catchment area of ORBEL pipelines. The modeling performed in this work was developed using the software Dinamica-EGO, using as input classified land cover maps obtained from Landsat 5/TM satellite images as well as spatial variables to explain the observed changes in land cover. For the model calibration, we used the method of weights of evidence that is available at Dinamica-EGO. Initially, the maps of continuous variables were categorized according to discrete ranges, which were then employed for the calculation of the respective positive weights of evidence. Positive values foster certain transitions, while negative values indicate low probability of transition, and values close to zero have no effect on changes. Model validation was executed by means of the fuzzy similarity method using exponential decay. The results show that for the two study periods (1987-1998 and 1998-2010) the rate of change for the transition 'others to woody vegetation' is much higher than for the other transitions observed in the same... (Complete abstract click electronic access below) / Mestre
225

Simulation and compiler support for communication and mobility for environment sensing / Simulation et support du compilateur pour la communication et la mobilité pour la surveillance de I'environnement

Truong, Tuyen Phong 29 August 2018 (has links)
Les transmissions radio à longue portée et basse énergie ouvrent de nouveaux champs d'application pour les capteurs, en particulier pour la surveillance de l'environnement. Le protocole radio LoRa permet, par exemple, de connecter des capteurs à une distance pouvant aller jusqu'à dix kilomètres en ligne de visée. Cependant, la grande surface couverte amène plusieurs difficultés, telles que le placement spatial en regard de la topologie géographique, ou la variabilité de la latence des communications. Le positionnement dans I'environnement comporte également des contraintes liées à I'intérêt des points de mesure du phénomène physique. Les critères de conception de ces réseaux tranchent donc avec les méthodes existantes (disques) quand on s'attaque aux terrains complexes. Cette thèse décrit des techniques de simulation basées sur I'analyse géographique cellulaire pour calculer les couvertures radio à longue portée et déduire les caractéristiques radios dans ces situations. Comme la propagation radio n'est qu'un cas particulier de phénomènes physiques, on montre qu'une approche unifiée cellulaire permet de caractériser beaucoup de comportements physiques potentiels. Le cas des fortes pluies et des inondations est étudié. L'analyse de la géographie est réalisée en utilisant des outils de segmentation pour produire des systèmes cellulaires qui sont à leur tour traduits en code pour des calculs de haute performance. La thèse fournit des résultats d'expériences de terrain complexes pratiques en utilisant LoRa, permettant de qualifier l'exactitude de la simulation des couvertures, et les caractéristiques d'ordonnancement des communications. Nous produisons des tables de performance pour les simulations sur les unités de traitement graphique (GPUs) qui montrent que le choix d'une algorithmique parallèle est pertinent sur ces problèmes. / Long-range radio transmissions open new sensor application fields, in particular for environment monitoring. For example, the LoRa radio protocol enables to connect remote sensors at distance as long as ten kilometers in a line-of-sight. However, the large area covered also brings several difficulties, such as the placement of sensing devices in regard to topology in geography, or the variability of communication latency. Sensing the environment also carries constraints related to the inlerest of sensing points in relation with a physical phenomenon. Thus criteria for designs are evolving a lot from the existing methods, especially in complex terrains. This thesis describes simulation techniques based on geography analysis to compute long-range radio coverages and radio characteristics in these situations. As radio propagation is just a particular case of physical phenomena, it is shown how a unified approach also allows to characterize the behavior of potential physical risks. The case of heavy rainfall and flooding is investigated. Geography analysis is achieved using segmentation tools to produce cellular systems which are in turn translated into code for high-þerformance computations. The thesis provides results from practical complex terrain experiments using LoRa which confirm the accuracy of the simulation, and scheduling characteristics for sample networks. Performance tables are produced for these simulations on current Graphics Processing Units (GPUs).
226

Formal approaches to a definition of agents

Biehl, Martin Andreas January 2017 (has links)
This thesis is a contribution to the formalisation of the notion of an agent within the class of finite multivariate Markov chains. In accordance with the literature agents are are seen as entities that act, perceive, and are goaldirected. We present a new measure that can be used to identify entities (called i-entities). The intuition behind this is that entities are spatiotemporal patterns for which every part makes every other part more probable. The measure, complete local integration (CLI), is formally investigated within the more general setting of Bayesian networks. It is based on the specific local integration (SLI) which is measured with respect to a partition. CLI is the minimum value of SLI over all partitions. Upper bounds are constructively proven and a possible lower bound is proposed. We also prove a theorem that shows that completely locally integrated spatiotemporal patterns occur as blocks in specific partitions of the global trajectory. Conversely we can identify partitions of global trajectories for which every block is completely locally integrated. These global partitions are the finest partitions that achieve a SLI less or equal to their own SLI. We also establish the transformation behaviour of SLI under permutations of the nodes in the Bayesian network. We then go on to present three conditions on general definitions of entities. These are most prominently not fulfilled by sets of random variables i.e. the perception-action loop, which is often used to model agents, is too restrictive a setting. We instead propose that any general entity definition should in effect specify a subset of the set of all spatiotemporal patterns of a given multivariate Markov chain. Any such definition will then define what we call an entity set. The set of all completely locally integrated spatiotemporal patterns is one example of such a set. Importantly the perception-action loop also naturally induces such an entity set. We then propose formal definitions of actions and perceptions for arbitrary entity sets. We show that these are generalisations of notions defined for the perception-action loop by plugging the entity-set of the perception-action loop into our definitions. We also clearly state the properties that general entity-sets have but the perception-action loop entity set does not. This elucidates in what way we are generalising the perception-action loop. Finally we look at some very simple examples of bivariate Markov chains. We present the disintegration hierarchy, explain it via symmetries, and calculate the i-entities. Then we apply our definitions of perception and action to these i-entities.
227

[en] SIMULATION AND AUTOMATIC SYNTHESES OF QUANTUM DOTS CELLULAR AUTOMATA CIRCUITS THOUGHT INTELLIGENT TECHNIQUES / [pt] SIMULAÇÃO E SÍNTESE AUTOMÁTICA DE CIRCUITOS DE AUTÔMATOS CELULARES COM PONTOS QUÂNTICOS ATRAVÉS DE TÉCNICAS INTELIGENTES

OMAR PARANAIBA VILELA NETO 26 July 2006 (has links)
[pt] Esta dissertação investiga e propõe um novo simulador de circuitos de Autômatos Celulares com Pontos Quânticos (QCA) e uma nova metodologia para a criação e otimização de circuitos lógicos, utilizando técnicas da inteligência computacional. Autômatos Celulares com Pontos Quânticos é uma nova tecnologia, na escala nanométrica, que tem chamado a atenção dos pesquisadores por ser uma alternativa à tecnologia CMOS, cujo limite físico de miniaturização será atingido nos próximos anos. QCA tem um grande potencial no desenvolvimento de circuitos com maior densidade espacial, maior velocidade, baixa dissipação e baixo consumo de energia. Ao contrário das tecnologias tradicionais, QCA não codifica a informação pelo fluxo de corrente elétrica, mas pela configuração das cargas elétricas no interior das células. A interação coulombiana entre as células garante o fluxo da informação. Apesar de simples, essas características fazem com que a arquitetura de circuitos de QCA se torne não trivial. Portanto, a criação de um simulador e de uma metodologia de elaboração e síntese automática de circuitos possibilitam aos cientistas uma melhor visualização de como esses dispositivos funcionam, acelerando o desenvolvimento desses sistemas na escala nanométrica. Para atingir o objetivo proposto, técnicas de inteligência computacional, tais como redes neurais do tipo Hopfield, para o desenvolvimento do simulador, e algoritmos genéticos, para a metodologia de criação e otimização dos circuitos, foram empregadas. Os resultados encontrados foram significativos, comprovando que as técnicas da inteligência computacional podem ser uma ferramenta estratégica para o rápido desenvolvimento da nanoeletrônica e da nanotecnologia em geral. / [en] This dissertation investigates and considers a new simulator of Quantum Dots Cellular Automata (QCA) Circuits and a new methodology for the synthesis and optimization of logical circuits, by means of Computational Intelligence. Quantum-dot Cellular Automata (QCA) is a new technology in the nanometric scale which has called attention from researchers as one alternative for the CMOS technology, which is reaching its physical limitation. QCA have a large potential in the development of circuits with high space density and low heat dissipation, and can allow the development of faster computers with lower power consumption. Differently from the conventional technologies, QCA do not codify information by means of electric current flow, but rather by the configuration of electrical charges in the interior of the cells. The Coulomb interaction between cells is responsible by the flow of information. Despite simple, these features become the design of logical devices into a non-trivial task. Therefore, the development of a simulator and a methodology of automatic synthesis of QCA circuits make possible to the scientist a better evaluation of how these circuits work, accelerating the development of these new systems in the nanometer scale. To reach the proposed target, Computational Intelligence techniques were used. The first results show that these techniques are capable of simulating efficiently and fast, synthesizing optimized circuits with a reduced number of cells. Such optimization reduces the possibility of failures and guarantees higher speed.
228

Hardware reconfigurável para geração de música harmonizada utilizando autômatos celulares. / Reconfigurable hardware for music composition using cellular automata.

Heloísa Diná Félix Lima Bezerra 29 August 2013 (has links)
Desde os primórdios da humanidade, a descoberta do método de processamento cerebral do som, e consequentemente da música, fazem parte do imaginário humano. Portanto, as pesquisas relacionadas a este processo constituem um dos mais vastos campos de estudos das áreas de ciências. Dentre as inúmeras tentativas para compreensão do processamento biológico do som, o ser humano inventou o processo automático de composição musical, com o intuito de aferir a possibilidade da realização de composições musicais de qualidade sem a imposição sentimental, ou seja, apenas com a utilização das definições e estruturas de música existentes. Este procedimento automático de composição musical, também denominado música aleatória ou música do acaso, tem sido vastamente explorado ao longo dos séculos, já tendo sido utilizado por alguns dos grandes nomes do cenário musical, como por exemplo, Mozart. Os avanços nas áreas de engenharia e computação permitiram a evolução dos métodos utilizados para composição de música aleatória, tornando a aplicação de autômatos celulares uma alternativa viável para determinação da sequência de execução de notas musicais e outros itens utilizados durante a composição deste tipo de música. Esta dissertação propõe uma arquitetura para geração de música harmonizada a partir de intervalos melódicos determinados por autômatos celulares, implementada em hardware reconfigurável do tipo FPGA. A arquitetura proposta possui quatro tipos de autômatos celulares, desenvolvidos através dos modelos de vizinhança unidimensional de Wolfram, vizinhança bidimensional de Neumann, vizinhança bidimensional Moore e vizinhança tridimensional de Neumann, que podem ser combinados de 16 formas diferentes para geração de melodias. Os resultados do processamento realizado pela arquitetura proposta são melodias no formato .mid, compostas através da utilização de dois autômatos celulares, um para escolha das notas e outro para escolha dos instrumentos a serem emulados, de acordo com o protocolo MIDI. Para tal esta arquitetura é formada por três unidades principais, a unidade divisor de frequência, que é responsável pelo sincronismo das tarefas executadas pela arquitetura, a unidade de conjunto de autômatos celulares, que é responsável pelo controle e habilitação dos autômatos celulares, e a unidade máquina MIDI, que é responsável por organizar os resultados de cada iteração corrente dos autômatos celulares e convertê-los conforme a estrutura do protocolo MIDI, gerando-se assim o produto musical. A arquitetura proposta é parametrizável, de modo que a configuração dos dados que influenciam no produto musical gerado, como por exemplo, a definição dos conjuntos de regras para os autômatos celulares habilitados, fica a cargo do usuário, não havendo então limites para as combinações possíveis a serem realizadas na arquitetura. Para validação da funcionalidade e aplicabilidade da arquitetura proposta, alguns dos resultados obtidos foram apresentados e detalhados através do uso de técnicas de obtenção de informação musical. / Since the beginnings of mankind, questions about the method of sound processing in the brain, and hence the music, are part of the human imagination. Therefore, the researches related to this process constitute one of the largest fields of research in science. Among many attempts to understand the biological processing of sound, humans beings invented the automatic musical composition automatic process in order to verify the possibility of producing quality musical compositions, without the human interference, wich means, only by using the definitions and structures of existing pieces of music. This automatic music composition procedure, also known as random music, has been widely exploited over the past centuries, being used by greats musicians like Mozart. The advances in engineering and computing allowed the evolution of random music composition methods, making the application of cellular automata a viable alternative to determine the execution sequence of musical notes, as well as, other items used in this type of composition. This dissertation proposes a hardware architecture for random music composition using cellular automata to determine the melodic intervals order. A prototype has been implemented in FPGA. The proposed hardware architecture has four kind of cellular automata, modeled according to the one-dimensional Wolfram neighborhood, two-dimensional Neumann neighborhood, two-dimensional Moore neighborhood and three-dimensional Neumann neighborhood. These cellular automata can be combined in sixteen different ways for generating melodies. The processing result as conducted by the proposed architecture are melodies in the .mid format, through the use of two cellular automata, one for selecting notes and the others for choosing the instruments to be emulated, in accordance with the MIDI protocol. This hardware is composed by three main units, the frequency divider unit, which is responsible for the synchronizing of the tasks performed by the hardware architecture, the cellular automata set unit, which is responsible for the control and enabling of the cellular automata and the MIDI machine, which is responsible for organizing the iterations of the cellular automata and convert them to the MIDI protocol structure, generating the final musical composition. The proposed hardware architecture is parametrizable, so that the data settings that influence the final product, such as, the rules of the cellular automata, are informed by the user. There are no limits regarding the possible combinations to be performed in the hardware architecture. In order to validate the functionality and applicability of the proposed hardware, some results were presented and detailed through the use of techniques for musical information retrieval.
229

Utilização de modelo matemático na busca do manejo sustentável das pastagens naturais / Use of mathematical model in the search of sustainable management of natural grasslands

Martins, Carlos Eduardo Nogueira 28 February 2011 (has links)
The objective was to model on a scale spatiotemporal dynamics of rangeland vegetation types characterized by functional when subjected to different disorders, aiming to predict patterns in the vegetation inventory for future analysis of the fractal dimension associated with the model of cellular automata. So, initially evaluated the use of fractal analysis as a tool to determine patterns in a reduced scale of grazing on natural pastures under different managements. The experiment evaluated the effect of grazing and burning disturbances applied in two relief positions in a natural grassland located in Santa Maria-RS. Another area located in Bagé-RS assesses the improvement of natural grassland with the introduction of ryegrass, white clover and birdsfoot trefoil. The diversity of the pasture was derived by Shannon and Equitabilidade indices. The information fractal dimension was calculated by regression between the Shannon index(ε) and ε natural algorithm, and the slope of the fractal dimension information. The results showed that the fractal dimension can be a tool for determining patterns in plant community in small-scale grazing. The limitation of this technique to small scales is the need for a greater number of repetitions. Secondly, we validated a model is spatially explicit empirical predictive vegetation dynamics of a natural grassland subjected to different disorders based on cellular automata using the approach of plant functional types by comparing the model predictions with actual observations of experiments. The simulations were performed in two temporal and spatial scales, small and large. The temporal resolution of monthly simulation was considered when the spatial dimension was 0.0625 square meters, featuring a reduced scale. A wide range was considered when the temporal resolution was annual and the spatial dimension was 306.25 m². The factors were: grazing, absence and presence, he burns the absence and presence and position of relief, slope and lowland. The model consists of a three-dimensional array, the first being characterized by the temporal dimension and the second and third, representing flat two-dimensional space, each cell being a PFT, which changes with each step in time as the composition of cell itself and the eight neighboring cells. The model evaluated proved to be efficient in predicting the dynamics of natural grassland vegetation can be used to simulate different scenarios. However, the limitation of the model is correct in determining the level of disturbance. Finally, we introduced the fractal dimension to the previously mentioned model and simulated the effect of grazing management of the biennial burns or every three years, with each simulation corresponded to 100 iterations with a spatial resolution of 306.25 m² and temporal equal to one year. The level of disturbance adopted to characterize both the grazing and burning was 0.18. In the treatments with burns, the years when it was used the level of disorder was 0.36, corresponding to the sum of grazing disturbance and burning. The treatments were evaluated in relation to two situations of environmental resources (and with great restraint). The evaluation of fractal dimension in spatially explicit model based on cellular automata has proven to be a viable tool to determine patterns and dynamics of plant communities regardless of scale. The model does not adequately simulated the colonization of species, this being a key topic for future studies that use this approach. The use of only two functional types allowed better visualization of results. The determination of the amount of functional types to be used in the simulation will depend on further investigations. / O objetivo deste trabalho foi modelar em uma escala espaço-temporal a dinâmica vegetacional de pastagens naturais caracterizada por tipos funcionais quando submetidas a diferentes distúrbios, visando predizer padrões na vegetação de inventários futuros pela análise da dimensão fractal associada ao modelo de autômatos celulares. Assim, inicialmente avaliou-se o emprego da análise fractal como ferramenta na determinação de padrões em uma escala reduzida de pastejo sobre pastagens naturais submetidas a diferentes manejos. O experimento avaliou o efeito dos distúrbios pastejo e queima, aplicados em duas posições de relevo, em uma pastagem natural localizada em Santa Maria-RS. Outra área avaliada localizou-se em Bagé-RS onde foram introduzidos azevém, trevo branco e cornichão na pastagem natural. A diversidade da pastagem foi obtida pelos índices de Shannon e Equitabilidade. A informação da dimensão fractal foi calculada pela regressão entre o índice de Shannon(ε) e o algoritmo natural de ε, sendo a inclinação da linha a informação da dimensão fractal. Os resultados demonstraram que a dimensão fractal pode ser uma ferramenta na determinação de padrões na comunidade vegetal na escala reduzida de pastejo. A limitação do emprego desta técnica para escalas reduzidas é a necessidade de um número maior de repetições. Num segundo momento, validou-se um modelo espacialmente explícito empírico e preditivo da dinâmica vegetacional de uma pastagem natural submetida a diferentes distúrbios. Esse foi baseado em autômatos celulares, utilizando a abordagem de tipos funcionais de plantas, através da comparação das predições do modelo com observações reais de experimentos. As simulações foram realizadas em duas escalas temporais e espaciais, reduzida e ampla. A resolução temporal da simulação foi mensal quando a dimensão espacial considerada foi de 0,0625 m², caracterizando a escala reduzida. A escala ampla foi considerada quando a resolução temporal foi anual e a dimensão espacial foi de 306,25 m². Os fatores testados foram: pastejo, ausência e presença; queima, ausência e presença e posição de relevo, encosta e baixada. O modelo é formado por uma matriz representando duas dimensões espaciais planas, sendo cada célula um PFT, a qual se altera a cada passo no tempo conforme a composição da própria célula e de oito células vizinhas. O modelo avaliado demonstrou eficiência na predição da dinâmica da vegetação da pastagem natural podendo ser utilizado para simular diferentes cenários. Entretanto, a limitação do modelo está na correta determinação do nível de distúrbio. Por fim, avaliou-se a dimensão fractal ao modelo citado anteriormente e simulou-se o efeito do pastejo no manejo da queima bianual ou a cada três anos, sendo que cada simulação correspondeu a 100 iterações com resolução espacial de 306,25 m² e temporal igual a um ano. O nível de distúrbio adotado para caracterizar tanto o pastejo como a queima foi de 0,18. Nos tratamentos com queima, nos anos em que ela foi utilizada, o nível de distúrbio foi de 0,36, correspondendo a soma dos distúrbios pastejo e queima. Os tratamentos foram avaliados em relação a duas situações de recurso ambiental (ótimo e com restrição). A avaliação da dimensão fractal em modelo espacialmente explícitos baseados em autômatos celulares demonstrou ser uma ferramenta viável na determinação de padrões e da dinâmica da comunidade vegetal independente da escala. O modelo não simulou adequadamente a colonização de espécies, sendo este um tema fundamental para futuros trabalhos que utilizarem esta abordagem. A utilização de apenas dois tipos funcionais permitiu uma melhor visualização dos resultados. A determinação da quantidade de tipos funcionais a serem utilizados na simulação dependerá de futuras investigações.
230

Modelagem dinâmica espacial aplicada na avaliação das mudanças da cobertura da terra no entorno de dutos utilizando autômatos celulares: estudo de caso duto ORBEL

Delaneze, Marcelo Elias [UNESP] 14 October 2011 (has links) (PDF)
Made available in DSpace on 2014-06-11T19:26:10Z (GMT). No. of bitstreams: 0 Previous issue date: 2011-10-14Bitstream added on 2014-06-13T19:13:04Z : No. of bitstreams: 1 delaneze_me_me_rcla.pdf: 1472015 bytes, checksum: 1596836f4441d15a50d94daf73c5a740 (MD5) / Agência Nacional do Petróleo, Gás Natural e Biocombustíveis (ANP) / A obtenção de informação sobre as condições da rede dutoviária representa papel primordial na operação dos dutos, não só com o propósito de manter a eficiência operacional, mas também, para a minimização dos riscos associados a possíveis acidentes, tanto decorrentes dos processos naturais quanto de causas antrópicas relacionadas ao uso e cobertura da terra. Neste sentido, o emprego de modelos matemáticos em estudos ambientais gera importantes contribuições científicas ao planejamento ordenado de uma área, uma vez que ajudam a entender o impacto das mudanças no uso e cobertura da terra e a prever alterações futuras nos ecossistemas. A área de estudo compreende porções dos municípios de Duque de Caxias, Belford Roxo e Nova Iguaçu e tem por objetivo realizar experimentos de mudanças da cobertura da terra em médio prazo (10 anos) para a faixa de dutos ORBEL. A modelagem realizada neste trabalho foi desenvolvida no software Dinamica-EGO, utilizando como entrada mapas classificados de cobertura da terra, obtidos através de imagens do satélite Landsat 5/TM, e variáveis espaciais para explicar as mudanças ocorridas na cobertura da terra. Para a calibração do modelo, utilizou-se o método de pesos de evidência, disponível no Dinamica-EGO, primeiramente categorizando-se os mapas de variáveis contínuas e, posteriormente, calculando-se os pesos de evidência. Valores positivos favorecem determinada transição, enquanto valores negativos indicam baixa probabilidade de transição, e valores próximos a zero não exercem efeito. A validação do modelo se deu pelo método de similaridade fuzzy, com decaimento exponencial. Os resultados mostram que, para os dois períodos analisados (1987-1998 e 1998-2010), a taxa de mudança para a transição “vegetação arbórea para outros” é bem maior do que para... / Reliable information about conditions of pipeline network represents a major role in the operation of pipelines, not only in order to maintain operational efficiency, but also to minimize the risks associated with possible accidents such as rupture of the ducts due to landslides or mudslides mass block, causing damage to humans and the environment. The use of mathematical models in environmental studies allows significant scientific contributions to the physical planning of an area, since they help to understand the impact of changes in land use and land cover and predict future trends of changes in ecosystems. The study area includes portions of the municipalities of Duque de Caxias, Nova Iguaçu, and Belford Roxo and aims to carry out experiments in land-cover changes in the medium-term (10 years) within the catchment area of ORBEL pipelines. The modeling performed in this work was developed using the software Dinamica-EGO, using as input classified land cover maps obtained from Landsat 5/TM satellite images as well as spatial variables to explain the observed changes in land cover. For the model calibration, we used the method of weights of evidence that is available at Dinamica-EGO. Initially, the maps of continuous variables were categorized according to discrete ranges, which were then employed for the calculation of the respective positive weights of evidence. Positive values foster certain transitions, while negative values indicate low probability of transition, and values close to zero have no effect on changes. Model validation was executed by means of the fuzzy similarity method using exponential decay. The results show that for the two study periods (1987-1998 and 1998-2010) the rate of change for the transition 'others to woody vegetation' is much higher than for the other transitions observed in the same... (Complete abstract click electronic access below)

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