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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.
111

Numerical Conformal mappings for regions Bounded by Smooth Curves

Andersson, Anders January 2006 (has links)
<p>Inom många tillämpningar används konforma avbildningar för att transformera tvådimensionella områden till områden med enklare utseende. Ett exempel på ett sådant område är en kanal av varierande tjocklek begränsad av en kontinuerligt deriverbar kurva. I de tillämpningar som har motiverat detta arbete, är det viktigt att dessa egenskaper bevaras i det område en approximativ konform avbildning producerar, men det är också viktigt att begränsningskurvans riktning kan kontrolleras, särkilt i kanalens båda ändar.</p><p>Denna avhandling behandlar tre olika metoder för att numeriskt konstruera konforma avbildningar mellan ett enkelt standardområde, företrädesvis det övre halvplanet eller enhetscirkeln, och ett område begränsat av en kontinuerligt deriverbar kurva, där begränsningskurvans riktning kan kontrolleras, exakt eller approximativt.</p><p>Den första metoden är en utveckling av en idé, först beskriven av Peter Henrici, där en modifierad Schwarz-Christoffel-avbildning avbildar det övre halvplanet konformt på en polygon med rundade hörn.</p><p>Med utgångspunkt i denna idé skapas en algoritm för att konstruera avbildningar på godtyckliga områden med släta randkurvor.</p><p>Den andra metoden bygger också den på Schwarz-Christoffel-avbildningen, och utnyttjar det faktum att om enhetscirkeln eller halvplanet avbildas på en polygon kommer ett område Q i det inre av dessa, som till exempel en cirkel med centrum i origo och radie mindre än 1, eller ett område i övre halvplanet begränsat av två strålar, att avbildas på ett område R i det inre av polygonen begränsat av en slät kurva. Vi utvecklar en metod för att hitta ett polygonalt område P, utanför det Omega som man önskar att skapa en avbildning för, sådant att den Schwarz-Christoffel-avbildning som avbildar enhetscirkeln eller halvplanet på P, avbildar Q på Omega.</p><p>I båda dessa fall används tangentpolygoner för att numeriskt bestämma den önskade avbildningen.</p><p>Slutligen beskrivs en metod där en av Don Marshalls så kallade zipper-algoritmer används för att skapa en avbildning mellan det övre</p><p>halvplanet och en godtycklig kanal, begränsad av släta kurvor, som i båda ändar går mot oändligheten som räta parallella linjer.</p> / <p>In many applications, conformal mappings are used to transform two-dimensional regions into simpler ones. One such region for which conformal mappings are needed is a channel bounded by continuously differentiable curves. In the applications that have motivated this work, it is important that the region an approximate conformal mapping produces, has this property, but also that the direction of the curve can be controlled, especially in the ends of the channel.</p><p>This thesis treats three different methods for numerically constructing conformal mappings between the upper half-plane or unit circle and a region bounded by a continuously differentiable curve, where the direction of the curve in a number of control points is controlled, exact or approximately.</p><p>The first method is built on an idea by Peter Henrici, where a modified Schwarz-Christoffel mapping maps the upper half-plane conformally on a polygon with rounded corners. His idea is used in an algorithm by which mappings for arbitrary regions, bounded by smooth curves are constructed.</p><p>The second method uses the fact that a Schwarz-Christoffel mapping from the upper half-plane or unit circle to a polygon maps a region Q inside the half-plane or circle, for example a circle with radius less than 1 or a sector in the half--plane, on a region Omega inside the polygon bounded by a smooth curve. Given such a region Omega, we develop methods to find a suitable outer polygon and corresponding Schwarz-Christoffel mapping that gives a mapping from Q to Omega.</p><p>Both these methods use the concept of tangent polygons to numerically determine the coefficients in the mappings.</p><p>Finally, we use one of Don Marshall's zipper algorithms to construct conformal mappings from the upper half--plane to channels bounded by arbitrary smooth curves, with the additional property that they are parallel straight lines when approaching infinity.</p>
112

Uma seqüência de ensino para o estudo das propriedades dos polígonos via pavimentação

Santos, Amarildo Aparecido dos 23 October 2007 (has links)
Made available in DSpace on 2016-04-27T16:58:26Z (GMT). No. of bitstreams: 1 Amarildo Aparecido dos Santos.pdf: 6525411 bytes, checksum: ec2c28d9863cac89f1bf7a7c50f588b8 (MD5) Previous issue date: 2007-10-23 / Secretaria da Educação do Estado de São Paulo / O objetivo do presente trabalho é investigar o envolvimento de alunos da 8ª série do Ensino Fundamental no estudo das propriedades dos polígonos a partir de pavimentação no plano. Refletindo sobre este objetivo surgiu a questão de pesquisa: Em que medida um trabalho de exploração com as pavimentações no plano favorece o estudo das propriedades dos polígonos?, criamos, então, uma seqüência de atividades, utilizando alguns elementos da metodologia de pesquisa denominada engenharia didática. A seqüência foi dividida em três blocos. O primeiro sobre o reconhecimento dos polígonos via manipulação de material concreto; o segundo com o uso do software Cabri Géomètre e o terceiro bloco no ambiente papel e lápis. A pesquisa foi amparada pelos pressupostos teóricos de Parzysz sobre o desenvolvimento do pensamento geométrico; pelas idéias de Machado, que sugere para a construção do pensamento geométrico a articulação entre quatro processos: percepção, construção, representação e concepção; pela teoria dos campos conceituais proposta por Vergnaud. A análise dos resultados obtidos na aplicação da seqüência mostrou que o trabalho realizado pelos alunos nos blocos I e II foi insuficiente para que os alunos atingissem a etapa de validações dedutivas, mas foi importante por solidificar conceitos, tais como o conceito de pavimentação e o conceito de polígono regular
113

Numerical Conformal mappings for regions Bounded by Smooth Curves

Andersson, Anders January 2006 (has links)
Inom många tillämpningar används konforma avbildningar för att transformera tvådimensionella områden till områden med enklare utseende. Ett exempel på ett sådant område är en kanal av varierande tjocklek begränsad av en kontinuerligt deriverbar kurva. I de tillämpningar som har motiverat detta arbete, är det viktigt att dessa egenskaper bevaras i det område en approximativ konform avbildning producerar, men det är också viktigt att begränsningskurvans riktning kan kontrolleras, särkilt i kanalens båda ändar. Denna avhandling behandlar tre olika metoder för att numeriskt konstruera konforma avbildningar mellan ett enkelt standardområde, företrädesvis det övre halvplanet eller enhetscirkeln, och ett område begränsat av en kontinuerligt deriverbar kurva, där begränsningskurvans riktning kan kontrolleras, exakt eller approximativt. Den första metoden är en utveckling av en idé, först beskriven av Peter Henrici, där en modifierad Schwarz-Christoffel-avbildning avbildar det övre halvplanet konformt på en polygon med rundade hörn. Med utgångspunkt i denna idé skapas en algoritm för att konstruera avbildningar på godtyckliga områden med släta randkurvor. Den andra metoden bygger också den på Schwarz-Christoffel-avbildningen, och utnyttjar det faktum att om enhetscirkeln eller halvplanet avbildas på en polygon kommer ett område Q i det inre av dessa, som till exempel en cirkel med centrum i origo och radie mindre än 1, eller ett område i övre halvplanet begränsat av två strålar, att avbildas på ett område R i det inre av polygonen begränsat av en slät kurva. Vi utvecklar en metod för att hitta ett polygonalt område P, utanför det Omega som man önskar att skapa en avbildning för, sådant att den Schwarz-Christoffel-avbildning som avbildar enhetscirkeln eller halvplanet på P, avbildar Q på Omega. I båda dessa fall används tangentpolygoner för att numeriskt bestämma den önskade avbildningen. Slutligen beskrivs en metod där en av Don Marshalls så kallade zipper-algoritmer används för att skapa en avbildning mellan det övre halvplanet och en godtycklig kanal, begränsad av släta kurvor, som i båda ändar går mot oändligheten som räta parallella linjer. / In many applications, conformal mappings are used to transform two-dimensional regions into simpler ones. One such region for which conformal mappings are needed is a channel bounded by continuously differentiable curves. In the applications that have motivated this work, it is important that the region an approximate conformal mapping produces, has this property, but also that the direction of the curve can be controlled, especially in the ends of the channel. This thesis treats three different methods for numerically constructing conformal mappings between the upper half-plane or unit circle and a region bounded by a continuously differentiable curve, where the direction of the curve in a number of control points is controlled, exact or approximately. The first method is built on an idea by Peter Henrici, where a modified Schwarz-Christoffel mapping maps the upper half-plane conformally on a polygon with rounded corners. His idea is used in an algorithm by which mappings for arbitrary regions, bounded by smooth curves are constructed. The second method uses the fact that a Schwarz-Christoffel mapping from the upper half-plane or unit circle to a polygon maps a region Q inside the half-plane or circle, for example a circle with radius less than 1 or a sector in the half--plane, on a region Omega inside the polygon bounded by a smooth curve. Given such a region Omega, we develop methods to find a suitable outer polygon and corresponding Schwarz-Christoffel mapping that gives a mapping from Q to Omega. Both these methods use the concept of tangent polygons to numerically determine the coefficients in the mappings. Finally, we use one of Don Marshall's zipper algorithms to construct conformal mappings from the upper half--plane to channels bounded by arbitrary smooth curves, with the additional property that they are parallel straight lines when approaching infinity.
114

Optimal steering for kinematic vehicles with applications to spatially distributed agents

Bakolas, Efstathios 10 November 2011 (has links)
The recent technological advances in the field of autonomous vehicles have resulted in a growing impetus for researchers to improve the current framework of mission planning and execution within both the military and civilian contexts. Many recent efforts towards this direction emphasize the importance of replacing the so-called monolithic paradigm, where a mission is planned, monitored, and controlled by a unique global decision maker, with a network centric paradigm, where the same mission related tasks are performed by networks of interacting decision makers (autonomous vehicles). The interest in applications involving teams of autonomous vehicles is expected to significantly grow in the near future as new paradigms for their use are constantly being proposed for a diverse spectrum of real world applications. One promising approach to extend available techniques for addressing problems involving a single autonomous vehicle to those involving teams of autonomous vehicles is to use the concept of Voronoi diagram as a means for reducing the complexity of the multi-vehicle problem. In particular, the Voronoi diagram provides a spatial partition of the environment the team of vehicles operate in, where each element of this partition is associated with a unique vehicle from the team. The partition induces, in turn, a graph abstraction of the operating space that is in a one-to-one correspondence with the network abstraction of the team of autonomous vehicles; a fact that can provide both conceptual and analytical advantages during mission planning and execution. In this dissertation, we propose the use of a new class of Voronoi-like partitioning schemes with respect to state-dependent proximity (pseudo-) metrics rather than the Euclidean distance or other generalized distance functions, which are typically used in the literature. An important nuance here is that, in contrast to the Euclidean distance, state-dependent metrics can succinctly capture system theoretic features of each vehicle from the team (e.g., vehicle kinematics), as well as the environment-vehicle interactions, which are induced, for example, by local winds/currents. We subsequently illustrate how the proposed concept of state-dependent Voronoi-like partition can induce local control schemes for problems involving networks of spatially distributed autonomous vehicles by examining different application scenarios.
115

Diagrama de Voronoi: uma exploração nas distâncias Euclidiana e do Táxi / A exploration in Euclidean distance and Taxi-distance

Santos, Paula Roberta Scaburi dos 16 December 2016 (has links)
O objetivo do presente trabalho é explorar o conceito do diagrama de Voronoi considerando a métrica euclidiana e a métrica do taxi. Após uma breve introdução, o segundo capítulo começa com uma definição informal de diagrama de Voronoi considerando a distância euclidiana e traz uma sequência para a construção do diagrama no plano para dois, três e quatro pontos, usando o conceito de mediatriz. Após essa sequência, é feita uma definição formal e são apresentadas algumas propriedades e resultados teóricos acerca do diagrama. No terceiro capítulo consideramos a ideia do diagrama de Voronoi na métrica do Táxi. Após a definição da métrica do táxi, exploramos alguns lugares geométricos relacionados como: a circunferência e mediatriz, destacando as diferenças e semelhanças com a métrica euclidiana. São apresentados alguns exemplos de diagramas para três e quatro pontos. O quarto capítulo considera uma ideia para a representação das regiões de influência do diagrama de Voronoi na distância euclidiana e na distância do táxi, usando o GeoGebra. As construções apresentadas envolvem o conceito de circunferência e mediatriz em cada métrica e sua relação com as regiões de influência do diagrama de Voronoi. Por fim, o quinto capítulo apresenta algumas sugestões de atividades para Ensino Médio relacionadas ao diagrama de Voronoi, envolvendo conceitos de Geometria Analítica e Plana. / The objective of the present work is to explore the concept of Voronoi diagram considering Euclidean distance and Taxi-distance. After a brief introduction, the second chapter begins with an informal definition of Voronoi diagram considering Euclidean distance and brings a sequence for the construction of the diagram in the plane for two, three and four points, using the concept of perpendicular bisector. After this sequence, a formal definition is introduced and some properties and theoretical results about the diagram are presented. In the third chapter we consider the ideia of Voronoi diagram in the Taxi-distance. After defining the taxi-distance, we explore some related geometric locus as circunference and bisectors, highlighting the differences and similarities with the Euclidean distances. Some examples for three- and four-point diagrams are presented. The fourth chapter considers an idea for the representation of the regions of influence of the Voronoi diagram in the Euclidean distance and the taxi-distance, using GeoGebra. The construction presented involve the concept of circumference and bisector in each metric and its relation with the regions of influence of the Voronoi diagram. Finally, the fifth chapter presents some suggestions of activities for High School students related to the Voronoi diagram, involving concepts of Analytical and Plane Geometry.
116

Výpočet prostorové distribuce srážek různými metodami a vyhodnocení rozdílu v úhrnech srážek na vybraném povodí / Calculation of the spatial distribution of precipitation by various methods and evaluation of the difference in totals of rainfall in a chosen catchment

VÁVRA, Miroslav January 2013 (has links)
This thesis engages various methods of calculation of the spatial distribution of precipitation and the evaluation of differences in totals of rainfall in a chosen catchment. The aim of this work was to choose suitable methods for the calculation of areal rainfall and subsequently to create those methods. Most methods were developed in the GIS program. The next objective was to explore differences in monthly precipitation from hydrological years 2006 and 2007 calculated in the catchment by chosen methods. Chosen methods for the calculation of the spatial distribution of precipitation in the catchment were: arithmetic mean, Thiessen polygons, isohyetal method and inverse distance weighting method. (IDW). As a suitable catchment was selected the catchment of the Kopaninský stream where relatively dense rainfall measurement network is installed. During the solution of this thesis the area of interest had to be extended by the area between the used rain gauges which was delimited in the GIS program. The reason for an enlargement was a fact that a decomposition of rain gauges in the catchment of the Kopaninský stream did not permit the creation of isohyetal lines in this whole catchment. During the calculation and the comparison of results of individual methods was found that results of used methods were surprisingly nearly the same. It was also stated that not even sufficient dense rain gauges network does not guarantee 100% exactness for calculating the amount of the precipitation in the selected area because of their extraordinary variability.
117

Porovnání vývoje atmosférické depozice dusíku a fosforu v různých oblastech ČR / A comparison of the development of atmospheric deposition of nitrogen and phosphorus in different regions of the Czech Republic

SUCHÁ, Jitka January 2014 (has links)
This thesis engages a comparison of the development of atmospheric deposition of nitrogen and phosphorus in different regions of the Czech Republic. The work explains the formation of atmospheric deposition and related terms such as the source of pollution, emissions, air pollution and nitrogen oxides. There are stated types of atmospheric deposition, sampling procedure and the process of determining the size of atmospheric deposition. This work describes the methods that were used in the calculations and evaluations. It also deals with the selection of suitable measuring stations for processing the development of atmospheric nitrogen deposition. The atmospheric deposition of phosphorus were not measured in the territory of the Czech Republic in the period from 2000 to 2010. The aim of this work is to find trends in time series of concentrations of NOx and statistical evaluation of the development of atmospheric nitrogen deposition. For these chapters were selected concentration of nitrogen oxides in the regional towns of the Czech Republic. In the chapter of spatial analyzes of the concentration of nitrogen oxides is selected Ústecký kraj, mainly due to the fact that this area is characterized by significantly high atmospheric deposition of nitrogen and total air pollution. A therm the Black Triangle is often used for this location.
118

Construções geométricas por dobradura (ORIGAMI): Aplicações ao ensino básico / Geometric constructions by folding ( ORIGAMI ) : applications to basic education

Luiz Claudio de Sousa Passaroni 30 January 2015 (has links)
A presente dissertação tem o objetivo de mostrar a arte Origami sob um contexto matemático, apresentando um pequeno resumo dos aspectos história e o desenvolvimento do Origami ao longo do tempo e dando maior destaque às suas aplicações na matemática, com o emprego dos axiomas de Huzita e a proposta de ampliação deste conjunto de axiomas com a inclusão da circunferência no papel Origami. Com o uso das técnicas de dobraduras, este trabalho mostra várias aplicações do Origami na matemática, tais como: a solução de alguns problemas clássicos, a construção de polígonos, a demonstração da soma dos ângulos internos de um triângulo, cálculo de algumas áreas, a solução de alguns problemas de máximos e mínimos, seguidos dos conceitos matemático envolvidos em cada um deles. E a inclusão da circunferência no plano Origami permitiu ainda, o estudo das construções das cônicas por dobraduras / This work aims to demonstrate the Origami art in a mathematical context, with a brief summary of the historical aspects and its development over time, giving more prominence to applications in mathematics, with the use of the axioms of Huzita and proposal to expand this set of axioms to include the circle in Origami paper. As the use of folding techniques, this work shows various applications of Origami in mathematics, such as the solution of some classical problems; the construction of polygons; the demonstration of the sum of the interior angles of a triangle; the calculation of some areas and the solution of some problems of maximum and minimum, followed by mathematical concepts involved in each of them. The inclusion of the circle in Origami plan allowed also to study the constructions of conic by folding
119

Construções geométricas por dobradura (ORIGAMI): aplicações ao ensino básico / Geometric constructions by folding ( ORIGAMI ) : applications to basic education.

Luiz Claudio de Sousa Passaroni 30 January 2015 (has links)
A presente dissertação tem o objetivo de mostrar a arte Origami sob um contexto matemático, apresentando um pequeno resumo dos aspectos história e o desenvolvimento do Origami ao longo do tempo e dando maior destaque às suas aplicações na matemática, com o emprego dos axiomas de Huzita e a proposta de ampliação deste conjunto de axiomas com a inclusão da circunferência no papel Origami. Com o uso das técnicas de dobraduras, este trabalho mostra várias aplicações do Origami na matemática, tais como: a solução de alguns problemas clássicos, a construção de polígonos, a demonstração da soma dos ângulos internos de um triângulo, cálculo de algumas áreas, a solução de alguns problemas de máximos e mínimos, seguidos dos conceitos matemático envolvidos em cada um deles. E a inclusão da circunferência no plano Origami permitiu ainda, o estudo das construções das cônicas por dobraduras. / This work aims to demonstrate the Origami art in a mathematical context, with a brief summary of the historical aspects and its development over time, giving more prominence to applications in mathematics, with the use of the axioms of Huzita and proposal to expand this set of axioms to include the circle in Origami paper. As the use of folding techniques, this work shows various applications of Origami in mathematics, such as the solution of some classical problems; the construction of polygons; the demonstration of the sum of the interior angles of a triangle; the calculation of some areas and the solution of some problems of maximum and minimum, followed by mathematical concepts involved in each of them. The inclusion of the circle in Origami plan allowed also to study the constructions of conic by folding.
120

Poliedros de Platão como estratégia no ensino da geometria espacial

Nogueira, Simone Paes Gonçalves January 2014 (has links)
Orientador: Prof. Dr. André Ricardo Oliveira da Fonseca / Dissertação (mestrado) - Universidade Federal do ABC, Programa de Pós-Graduação em Mestrado Profissional em Matemática em Rede Nacional, 2014. / Our work aims to make a brief study on polyhedrons, focusing specially on solid platonics. First, we will present the historical moment in which this topic was discussed, as well as mention the mathematicians who contributed to the first studies about it. Then, we will explain what are regular polygons, dihedral angle and regular polyhedron. We will also discuss the reasons why there are only five solid platonics and we will demonstrate the Euler Characteristics, through induction. We will provide sample activities, which can be used in classrooms, in order to in uence positivetly the learning process of students. Therefore, such students will be able to better learn and understand the content, rather than just decorating the \formulas". We will also show an intuitive idea of calculating the area and volumes of solid platonics, which is something rarely demonstrated in textbooks. Further on, we will demonstrate how this topic is presented by the National Curriculum Parameters \Parâmetros Curriculares Nacionais (PCN)", and relate it to how it is developed and and taught since the first years of schools until the second year of High School, time in which this topic is more deeply studied. There are sample questions, which can be found in national examinations, such as Saresp (São Paulo's government exam) and ENEM (Federal government exam). Throughout this work you will be able to see imagens that were taken during a project envolving students from a second High School year, which was taken place a public school.

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