Global ETD Search

251	Petrologia e geocronologia do Maciço Glória Norte, faixa de dobramentos sergipana, NE do Brasil Lisboa, Vinícius Anselmo Carvalho 11 March 2014 (has links) O Domínio Macururé, localizado na porção norte da Faixa de Dobramentos Sergipana, é caracterizado por apresentar um grande volume de granitos (s.l.) de idade Neoproterozóica. O Maciço Glória Norte (MGN), que ocorre na porção centronorte do Domínio Macururé, representa uma das mais importantes intrusões que se colocaram após o pico de deformação e metamorfismo no orógeno (630 Ma). Nesse estudo identificou-se a presença de duas fácies petrográficas nesse maciço: quartzomonzonítica porfirítica, quartzo-monzonítica, além de diques leucocráticos. Os enclaves de diversos tipos, são uma feição recorrente em toda a extensão do maciço, assim como texturas evidenciam a existência do processo de misturas entre magmas. Os estudos microscópicos permitiram a identificação de várias texturas de instabilidade, e uma sequência de cristalização marcada pelo aumento de fluídos ao longo da evolução do magma. Os dados geoquímicos revelam uma afinidade com as rochas da série shoshonítica e seus enclaves exibem afinidade ultrapotássica com conteúdos de MgO e K2O sempre maiores que 3%. Nos diagramas ETR percebeuse um enriquecimento de ETR leves em relação aos pesados, além de fortes anomalias negativas de Ta, Nb, Ti, P, Sr e Eu, principalmente nos enclaves. As temperaturas médias calculadas pelo geotermômetro de Zr revelam que o início da cristalização no MGN se deu entre 810°C e 784°C e teve seu fim entre 730°C e 700°C. A idade obtida através do método U/Pb SHRIMP (588 + 5,2 Ma) posiciona o magmatismo que deu origem ao MGN, no Período Ediacarano, marcando a ocorrência de um magmatismo a 588 Ma, que não foi afetado por eventos tectônicos. / The Domain Macururé located in the northern portion of Sergipano Fold Thrust Belt, is characterized by having a large volume of granites (s.l.) of Neoproterozoic age. The Gloria Norte Massif (GNM), which occurs in the north-central portion of the Domain Macururé, represents a major intrusion that arose after the peak of deformation and metamorphism in the orogen (+ 630 Ma). In this study we identified the presence of two petrographic facies in that massif: quartz-monzonitic porphyritic, quartz-monzonitic and leucocratic dykes. The enclaves, varied tipology, are a recurrent feature in the whole extent of the massif, as well as mixtures of texture of mixing and mingling. Microscopic studies allowed the identification of various textures of the mixing and a sequence of crystallization marked by increased fluids during the evolution of the magma. Geochemical data reveal an affinity with shoshonitic series rocks, and their enclaves exhibit ultrapotassic affinity, wich always show MgO and K2O contents greater than 3%. In the diagrams ETR perceives an enrichment of LREE relative to HREE, and strong negative anomalies of Ta, Nb, Ti, P, Sr, and Eu, mostly in enclaves. The average temperature calculated by Zr geothermometer showed that the onset of MGN crystallization occurred between 810°C and 784°C, and its end was between 730°C and 700°C. The ages obtained by U/Pb SHRIMP (588 + 5.2 Ma) positions the magmatism that gave rise to the MGN, in the Ediacaran and this age mark the occurrence of a magmatism (588 Ma), which was not significantly affected by tectonic events. Geociências Geocronologia Petrologia Paleontologia - Proterozoico Maciço Glória Norte Shoshonítico Neoproterozóico Faixa de Dobramentos Sergipana Earth sciences Geological time Paleontology Petrology Shoshonite Gloria Norte Massif Shoshonític Neoproterozoic Sergipano Fold Trust Belt
252	Movimentos sob atração focal em campos vetoriais planares / Motions under focal attraction in planar vector fields MARTINS, Tiberio Bittencourt de Oliveira 29 August 2008 (has links) Made available in DSpace on 2014-07-29T16:02:23Z (GMT). No. of bitstreams: 1 Dissertacao Tiberio Bittencourt.pdf: 638703 bytes, checksum: b4eef7616f38b5efeb40a4c5c26e0b75 (MD5) Previous issue date: 2008-08-29 / In this work, we develop the article On the motion under focal attraction in a rotating medium , of J. Sotomayor, which deals with a bidimensional differential system that model the following Biological problem: in a shallow recipient with circular section, with liquid in, spinning with angular speed ω, there are platyhelminthes, flatworms organisms, they are attracted by a fix lighting point near of the border of the recipient and they swim with a speed v in the direction of the this point. The problem is to show that there exists an equilibrium point where platyhelminthes go to cluster by the time passing. It s analyzed the dynamic of the model: existence of critical points and stability of the system and bifurcations. We analyzed three modifications of this system too. In the last part, it s discussed a criterium for non existence of periodic orbits of a planar vector fields in a simply connected region. / Neste trabalho, desenvolvemos o artigo On the motion under focal attraction in a rotating medium de J. Sotomayor [9] que trata de um sistema de equações diferenciais bidimensional que modela o seguinte problema na Biologia: num recipiente raso de seção circular, com líquido, girando a uma velocidade angular ω, existem platelmintos, organismos vermiforme, eles s ao atra´ıdos por um ponto luminoso fixo perto da borda do recipiente e nadam com uma velocidade v em direçãoa este ponto. O problema é mostrar que existe um ponto de equilíbrio onde os platelmintos vão se aglomerar com o passar do tempo. É analisada a dinâmica da modelagem: existência de pontos de equilibrio e estabilidade do sistema e bifurcaçoes. Analisamos tambem tres modificaçoes desse sistema. Na parte final, e discutido um criterio para determinaçao da ausencia de orbitas periodicas em campos vetoriais planares. Campos vetoriais planares Biologia Equações diferenciais bidimencionais Dinâmica de modelagem Platelmintos
253	Bank Customer Churn Prediction : A comparison between classification and evaluation methods Tandan, Isabelle, Goteman, Erika January 2020 (has links) This study aims to assess which supervised statistical learning method; random forest, logistic regression or K-nearest neighbor, that is the best at predicting banks customer churn. Additionally, the study evaluates which cross-validation set approach; k-Fold cross-validation or leave-one-out cross-validation that yields the most reliable results. Predicting customer churn has increased in popularity since new technology, regulation and changed demand has led to an increase in competition for banks. Thus, with greater reason, banks acknowledge the importance of maintaining their customer base. The findings of this study are that unrestricted random forest model estimated using k-Fold is to prefer out of performance measurements, computational efficiency and a theoretical point of view. Albeit, k-Fold cross-validation and leave-one-out cross-validation yield similar results, k-Fold cross-validation is to prefer due to computational advantages. For future research, methods that generate models with both good interpretability and high predictability would be beneficial. In order to combine the knowledge of which customers end their engagement as well as understanding why. Moreover, interesting future research would be to analyze at which dataset size leave-one-out cross-validation and k-Fold cross-validation yield the same results. machine learning cross-validation k-fold leave-one-out random forest decision trees k-nearest neighbor logistic regression supervised learning supervised statistical learning binary classification customer churn bank customer churn. Probability Theory and Statistics Sannolikhetsteori och statistik
254	Automatic Flight Maneuver Identification Using Machine Learning Methods Bodin, Camilla January 2020 (has links) This thesis proposes a general approach to solve the offline flight-maneuver identification problem using machine learning methods. The purpose of the study was to provide means for the aircraft professionals at the flight test and verification department of Saab Aeronautics to automate the procedure of analyzing flight test data. The suggested approach succeeded in generating binary classifiers and multiclass classifiers that identified six flight maneuvers of different complexity from real flight test data. The binary classifiers solved the problem of identifying one maneuver from flight test data at a time, while the multiclass classifiers solved the problem of identifying several maneuvers from flight test data simultaneously. To achieve these results, the difficulties that this time series classification problem entailed were simplified by using different strategies. One strategy was to develop a maneuver extraction algorithm that used handcrafted rules. Another strategy was to represent the time series data by statistical measures. There was also an issue of an imbalanced dataset, where one class far outweighed others in number of samples. This was solved by using a modified oversampling method on the dataset that was used for training. Logistic Regression, Support Vector Machines with both linear and nonlinear kernels, and Artifical Neural Networks were explored, where the hyperparameters for each machine learning algorithm were chosen during model estimation by 4-fold cross-validation and solving an optimization problem based on important performance metrics. A feature selection algorithm was also used during model estimation to evaluate how the performance changes depending on how many features were used. The machine learning models were then evaluated on test data consisting of 24 flight tests. The results given by the test data set showed that the simplifications done were reasonable, but the maneuver extraction algorithm could sometimes fail. Some maneuvers were easier to identify than others and the linear machine learning models resulted in a poor fit to the more complex classes. In conclusion, both binary classifiers and multiclass classifiers could be used to solve the flight maneuver identification problem, and solving a hyperparameter optimization problem boosted the performance of the finalized models. Nonlinear classifiers performed the best on average across all explored maneuvers. Flight Aircraft Machine Learning Flight Dynamics Classification Supervised Learning Support Vector Machines Neural Networks Logistic Regression Feature Selection Recursive Feature Elimination Feature Representation k-fold cross-validation maneuvers flight maneuvers Control Engineering Reglerteknik
255	The Dynamics of Twisted Tent Maps Chamblee, Stephen Joseph 12 July 2013 (has links) Indiana University-Purdue University Indianapolis (IUPUI) / This paper is a study of the dynamics of a new family of maps from the complex plane to itself, which we call twisted tent maps. A twisted tent map is a complex generalization of a real tent map. The action of this map can be visualized as the complex scaling of the plane followed by folding the plane once. Most of the time, scaling by a complex number will \twist" the plane, hence the name. The "folding" both breaks analyticity (and even smoothness) and leads to interesting dynamics ranging from easily understood and highly geometric behavior to chaotic behavior and fractals. twisted tent map complex dynamical system dynamics fractal coded-coloring escape-time fold folding reflect filled-in Julia set twisted tent map TTM complex plane polygon Fractals Julia sets Symbolic dynamics Twist mappings (Mathematics) Chaotic behavior in systems
256	"An Hungry Man Dreameth": Transcendental Film Theory and Stylistic Trends in Recent Institutional Films of the LDS Church Lewis, Mark T. 01 May 2016 (has links) To the religiously minded, few things carry greater importance than a connection to the divine. For centuries, the literature of prophets and the work of gifted artists have served to create a liminal space where man and Maker can meet. The advent of cinema and the creation of the Internet pose unique questions for the artist seeking to lead an audience toward an encounter with God. In a modern world where discretionary time is dominated by on-demand video streaming, the value of understanding cinema and its myriad potential is particularly relevant. As a religious organization, The Church of Jesus Christ of Latter-day Saints has eagerly (and to a certain extent, uniquely) embraced and used film to further its aims. This thesis will further the conversation already begun on the topic of spirituality in official LDS Church productions, particularly adding new analysis regarding the form and content of more recent institutionally produced films. How do stylistic trends in recent official film productions of the LDS Church relate to the broader academic and theological discussion regarding cinematic spirituality? After the introduction and thesis overview in Chapter 1, Chapter 2 will provide a survey of prominent works regarding cinematic spirituality. Theories that entertain how movies speak to human spirits are varied and highly subjective. Many theories about what makes a work "spiritual" grow from particular religious traditions and are informed by that theorist's beliefs about God's nature. Some theories are dependent on loosely measured criteria (editing pace, complexity of music, distance between camera and subject, etc.), while others rely almost entirely on the "feeling" a work conveys (which may or may not be determined by objectively measurable parts).Chapter 3 relates the prominent theories laid out in Chapter 2 to the cinematic efforts made by The Church of Jesus Christ of Latter-day Saints in the past two decades. Examining the form and content of these media projects will reveal trends that indicate inherent assumptions on the part of the LDS Church's media department regarding the purpose and potential of spirituality and film. Chapter 4 explores how the Church's typical approach compares and contrasts with films made by independent Latter-day Saint filmmakers. Some stylistic possibilities will be derived from the efforts of Mormon artists more generally and may have implications for how Latter-day Saint films could help spiritually engage audiences. Mormon cinema LDS Church media Mormon Messages I'm a Mormon Mormon film the Life of Jesus Christ Bible Videos Joseph Smith: Prophet of the Restoration Meet the Mormons Spirituality and film cinematic transcendence Paul Schrader Craig Detweiler Dean Duncan Religion
257	Continuity and event in Leibniz and Deleuze Movahedi Pour, Hamed 06 1900 (has links) La continuité a un statut compliqué pour Deleuze et Leibniz. Chez Leibniz, la continuité est omniprésente dans ses mathématiques et sa métaphysique, mais il est aussi le théoricien de l'individualité absolue des monades, qui peuvent être interprétées comme des discontinuités irréductibles. Chez Deleuze, le champ Idéal est parfois considéré comme une continuité, mais il se caractérise aussi par une affirmation de divergence (et d'incompossibilité), qui pourrait impliquer une sorte de discontinuité dans l'ordre virtuel. Cette étude aborde ce problème chez les deux penseurs et révèle le rôle de la continuité dans leur métaphysique. En effet, un concept deleuzien de continuité est reconstitué en explorant Le pli, Différence et répétition, et Logique du sens. Il est montré comment la continuité (chez les deux penseurs), en tant que concept mathématique, se transforme en une notion métaphysique indispensable à la philosophie de l'événement de Deleuze. Cette recherche développe les nuances conceptuelles d'une notion deleuzienne de continuité et identifie ses différents types, à savoir la continuité divergente, la continuité intensive, la continuité torsionnelle et la continuité ten(or)sionnelle. Cette analyse permet de mettre au premier plan la correspondance architectonique de la métaphysique de Deleuze dans ces trois livres, une architecture empreinte de continuité et de pli. / Continuity has a complicated status for Deleuze and Leibniz. For Leibniz, continuity is prevalent in his mathematics and metaphysics, but he is also known to be the theoretician of the absolute individuality of monads, which can be interpreted as irreducible discontinuities. For Deleuze, the Ideal field is sometimes regarded as continuity, but it is also characterized by an affirmation of divergence (and incompossibility), which might imply a kind of discontinuity in the virtual order. This study engages with this problem in both thinkers and discloses the role of continuity in their metaphysics. Indeed, a Deleuzian concept of continuity is reconstituted while exploring The Fold, Difference and Repetition, and Logic of Sense. It is shown how continuity (in both thinkers), as a mathematical concept, turns into a metaphysical notion that is indispensable for Deleuze’s philosophy of event. This research unfolds the conceptual nuances of a Deleuzian notion of continuity and identifies its different types, namely, divergent continuity, intensive continuity, torsional continuity, and ten(or)sional continuity. This analysis allows us to foreground the architectonic correspondence of Deleuze's metaphysics in these three books, an architecture imbued with continuity and fold. Deleuze Leibniz Continuity Event Fold Divergent continuity Intensive continuity Torsional continuity Tenorsional continuity Dramatization-poeticization Continuité Événement Pli Dramatisation-poétisation Continuité divergente Continuité intensive Continuité torsionnelle Continuité ten(or)sionnelle Philosophy / Philosophie (UMI : 0422)
258	Multifunctional Laminated Composites for Morphing Structures Chillara, Venkata Siva Chaithanya 13 September 2018 (has links) No description available. Aerospace Materials Automotive Materials Engineering Mechanical Engineering Mechanics laminated composite multifunctional prestressed curvature zero Poisson ratio anisotropy elastomer analytical model morphing bistable fold origami actuation fender skirt shape memory alloys fluidic strain energy minimization automotive
259	Demography of Birch Populations across Scandinavia Sendrowski, Janek January 2022 (has links) Boreal forests are particularly vulnerable to climate change, experiencing a much more drastic increase in temperatures and having a limited amount of more northern refugia. The trees making up these vast and important ecosystems already had to adapt previously to environmental pressures brought about by the repeated glaciations during past ice ages. Studying the patterns of adaption of these trees can thus provide valuable insights on how to mitigate future damage. This thesis presents and analyses population structure, demo- graphic history and the distribution of fitness effects (DFE) of the diploid Betula pendula and tetraploid B. pubescens across Scandinavia. Birches–being widespread in boreal forests as well as having great economical importance–constitute superb model species. The analyses of this work confirm the expectations on postglacial population expansion and diploid-tetraploid introgression. They furthermore ascertain the presence of two genetic clusters and a remarkably similar DFE for the species. This work also contributes with a transparent, reproducible and reusable pipeline which facilitates running similar analyses for related species. birch betula pubescens pendula betula pubescens betula pendula silver birch downy birch demography population structure distribution of fitness effects DFE dadi UMAP PCA ADMIXTURE polyDFE ice age glaciation tree boreal forest climate change adaption tetraploid diploid-tetraploid introgression Scandinavia genetic cluster pipeline snakemake bioinformatics reproducible population genetics postglacial population expansion demographic history FEEMS site-frequency spectrum SFS last glacial maximum LGM workflow python population expansion population growth EST-SFS 0-fold degenerate 4-fold degenerate maximum likelihood estimation MLE variant call format VCF single-nucleotide polymorphism SNP Bioinformatics (Computational Biology) Bioinformatik (beräkningsbiologi)
260	Achieving Complex Motion with Fundamental Components for Lamina Emergent Mechanisms Winder, Brian Geoffrey 01 March 2008 (has links) (PDF) Designing mechanical products in a competitive environment can present unique challenges, and designers constantly search for innovative ways to increase efficiency. One way to save space and reduce cost is to use ortho-planar compliant mechanisms which can be made from sheets of material, or lamina emergent mechanisms (LEMs). This thesis presents principles which can be used for designing LEMs. Pop-up paper mechanisms use topologies similar to LEMs, so it is advantageous to study their kinematics. This thesis outlines the use of planar and spherical kinematics to model commonly used pop-up paper mechanisms. A survey of common joint types is given, as well as an overview of common monolithic and layered mechanisms. In addition, it is shown that more complex mechanisms may be created by combining simple mechanisms in various ways. The principles presented are applied to the creation of new pop-up joints and mechanisms, which also may be used for lamina emergent mechanisms. Models of the paper mechanisms presented in Chapter 2 of the thesis are found in the appendix, and the reader is encouraged to print, cut out and assemble them. One challenge associated with spherical and spatial LEM design is creating joints with the desired motion characteristics, especially where complex spatial mechanism topologies are required. Hence, in addition to a study of paper mechanisms, some important considerations for designing joints for LEMs are presented. A technique commonly used in robotics, using serial chains of revolute and prismatic joints to approximate the motion of complex joints, is presented for use in LEMs. Important considerations such as linkage configuration and mechanism prototyping are also discussed. Another challenge in designing LEMs is creating multi-stable mechanisms with the ability to have coplanar links. A method is presented for offsetting the joint axes of a spatial compliant mechanism to introduce multi-stability. A new bistable spatial compliant linkage that uses that technique is introduced. In the interest of facilitating LEM design, the final chapter of this thesis presents a preliminary design method. While similar to traditional methods, this method includes considerations for translating the mechanism topology into a suitable configuration for use with planar layers of material. paper mechanism pop-up popup pop up mechanism linkage paper engineering paper crafts origami kinematics spatial mechanism planar mechanism bistable multi-stable spherical mechanism ortho-planar compliant PRBM pseudo-rigid-body model Lamina Emergent Mechanism LEM sheet goods planar layer complex joint elemental joint spatial joint degrees of freedom mechanism modeling mechanism design serial joint chain parallel series fundamental components complex motion revolute prismatic spherical cylindric universal half planar RSSR RCCC RSRC RTRT Altmann Bricard Bennett Goldberg 6R 4R joint axis angular offset paper joint V-fold circular arch figure-8 single slit double slit tube strap arch knee mechanism 45 degree fold solid shape floating layer tent Mechanical Engineering

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