• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 410
  • 58
  • 47
  • 19
  • 13
  • 11
  • 11
  • 11
  • 11
  • 11
  • 11
  • 7
  • 7
  • 4
  • 3
  • Tagged with
  • 690
  • 132
  • 95
  • 94
  • 76
  • 70
  • 62
  • 59
  • 56
  • 54
  • 46
  • 42
  • 38
  • 37
  • 36
  • 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.
481

Η πιθανολογική σκέψη στο νηπιαγωγείο : έρευνα και προοπτικές

Αντωνόπουλος, Κωνσταντίνος 06 September 2010 (has links)
Η παρούσα έρευνα επιχείρησε να ανιχνεύσει το βαθμό στον οποίο τα παιδιά προσχολικής ηλικίας αντιλαμβάνονται ορισμένες από τις βασικές έννοιες της Θεωρίας των Πιθανοτήτων. Παράλληλα, αξιολογήθηκε ένα κατάλληλα σχεδιασμένο εκπαιδευτικό πρόγραμμα με στόχο την εισαγωγή μίας μικρής ομάδας νηπίων στις συγκεκριμένες έννοιες. / The present research attempted to reveal the level of understanding of kids of preschool age as concerns some of the basic concepts in the Theory of Probabilities. Furthermore,we evaluated an appropriately designed educational program which aimed at introducing a small group of infants to these concepts.
482

Risk properties and parameter estimation on mean reversion and Garch models

Sypkens, Roelf 09 1900 (has links)
Most of the notations and terminological conventions used in this thesis are Statistical. The aim in risk management is to describe the risk factors present in time series. In order to group these risk factors, one needs to distinguish between different stochastic processes and put them into different classes. The risk factors discussed in this thesis are fat tails and mean reversion. The presence of these risk factors fist need to be found in the historical dataset. I will refer to the historical dataset as the original dataset. The Ljung- Box-Pierce test will be used in this thesis to determine if the distribution of the original dataset has mean reversion or no mean reversion. / Mathematical Sciences / M.Sc. (Applied Mathematics)
483

Probabilidades de spin quântico em temperatura positiva

Brasil, Jader Eckert January 2018 (has links)
Nesta dissertação estudamos uma probabilidade obtida a partir de conceitos da Mecânica Estatística Quântica do ponto de vista da Teoria Ergódica. A probabilidade é obtida a partir de um estado KMS sobre um lattice unidimensional de spins quânticos. Mostramos que esta probabilidade é mixing para o shift. Além disso, mostramos que vale um princípio dos grandes desvios para uma certa classe de funções e exploramos algumas propriedades do Jacobiano. Iremos considerar o estado KMS associado a um certo Hamiltoniano específico agindo sobre o lattice de spins quânticos. Nas seções iniciais vamos apresentar alguns conceitos e prerequisitos básicos (como operadores densidade, produto tensorial, C*-algebras e estados KMS) para o entendimento do resultado principal / In this dissertation we study a probability derived from Quantum Statistical Mechanics through the viewpoint of Ergodic Theory. The probability is obtained from a KMS state acting on a one dimensional lattice of quantum spins. We show that this probability is mixing for the shift map. Moreover, we show that a large deviation principle is true for a certain class of functions and we explore some properties of the Jacobian. We will consider the KMS state associated to a certain specific Hamiltonian acting on the quantum spin lattice. In the initial sections we will present some concepts and prerequisites (such as density operators, tensor product, C*-algebras and KMS states) for the understanding of our main results.
484

Uma análise histórica do desenvolvimento da probabilidade e a utilização de materiais concretos para seu ensino

Paulo, Francisco Ferreira de. 19 December 2013 (has links)
Submitted by Viviane Lima da Cunha (viviane@biblioteca.ufpb.br) on 2015-10-26T12:35:39Z No. of bitstreams: 1 arquivototal.pdf: 2479893 bytes, checksum: 60aafaee113077e24b3d8aa366626c32 (MD5) / Approved for entry into archive by Viviane Lima da Cunha (viviane@biblioteca.ufpb.br) on 2015-10-26T12:36:16Z (GMT) No. of bitstreams: 1 arquivototal.pdf: 2479893 bytes, checksum: 60aafaee113077e24b3d8aa366626c32 (MD5) / Made available in DSpace on 2015-10-26T12:36:16Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 2479893 bytes, checksum: 60aafaee113077e24b3d8aa366626c32 (MD5) Previous issue date: 2013-12-19 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The theme that sometimes we study A Historical Analysis of the Development and Use of Materials Probability concrete For your Teaching demand, considering the wealth of options, prioritize research with concrete materials and easy access to the student and the teacher. So we did a brief history of the origin and theories necessary for the calculation of probability applications involving gambling with coins, dice and playing cards, thus leading to a more concrete and useful way for meaningful student learning. / O tema que ora estudamos Uma análise histórica do desenvolvimento da probabilidade e a utilização de materiais concretos para seu ensino procura, diante da riqueza de opções, priorizar a pesquisa com materiais concretos e de fácil acesso ao aluno e ao professor. Assim, zemos um breve histórico da origem e das teorias necessárias às aplicações do cálculo de probabilidade, envolvendo jogos de azar com moedas, dados e baralhos, proporcionando, assim, um trabalho de forma concreta e útil para a aprendizagem signi cativa do aluno.
485

Probabilidades de spin quântico em temperatura positiva

Brasil, Jader Eckert January 2018 (has links)
Nesta dissertação estudamos uma probabilidade obtida a partir de conceitos da Mecânica Estatística Quântica do ponto de vista da Teoria Ergódica. A probabilidade é obtida a partir de um estado KMS sobre um lattice unidimensional de spins quânticos. Mostramos que esta probabilidade é mixing para o shift. Além disso, mostramos que vale um princípio dos grandes desvios para uma certa classe de funções e exploramos algumas propriedades do Jacobiano. Iremos considerar o estado KMS associado a um certo Hamiltoniano específico agindo sobre o lattice de spins quânticos. Nas seções iniciais vamos apresentar alguns conceitos e prerequisitos básicos (como operadores densidade, produto tensorial, C*-algebras e estados KMS) para o entendimento do resultado principal / In this dissertation we study a probability derived from Quantum Statistical Mechanics through the viewpoint of Ergodic Theory. The probability is obtained from a KMS state acting on a one dimensional lattice of quantum spins. We show that this probability is mixing for the shift map. Moreover, we show that a large deviation principle is true for a certain class of functions and we explore some properties of the Jacobian. We will consider the KMS state associated to a certain specific Hamiltonian acting on the quantum spin lattice. In the initial sections we will present some concepts and prerequisites (such as density operators, tensor product, C*-algebras and KMS states) for the understanding of our main results.
486

Alguns tópicos em probabilidade geométrica / Some topics in geometric probability

Pereira, Carlos André Bogéa 17 August 2018 (has links)
Orientador: Simão Nicolau Stelmastchuk / Dissertação (mestrado profissional) - Universidade Estadual de Campinas, Instituto de Matemática, Estatística e Computação Científica / Made available in DSpace on 2018-08-17T21:15:56Z (GMT). No. of bitstreams: 1 Pereira_CarlosAndreBogea_M.pdf: 2160729 bytes, checksum: f46cc601d486b802f179e9fd8befb099 (MD5) Previous issue date: 2011 / Resumo: Ao nosso entender, a Probabilidade Geométrica quantifica a probabilidade de ocorrer alguns fenômenos associados a entes geométricos. O primeiro estudo, talvez o mais famoso, a ser realizado neste sentido é o problema das agulhas de Buffon. A idéia deste estudo é simples. Traçadas duas retas paralelas a uma distância d, qual é a probabilidade de uma agulha de tamanho l tocar uma das retas? Neste trabalho nos dedicamos, inicialmente, a estudar este problema e sua resolução. Um segundo tópico do nosso trabalho foi baseado no seguinte problema: Suponha que uma antena transmissora de algum sinal, por exemplo, de celular, emite seus sinais uniformemente a uma distância a, em um plano. Se estou num ponto P do plano, qual a probabilidade de entrar na zona de emissão de sinal da antena se me deslocar até um raio b? Para a resolução deste problema nós utilizamos probabilidade contínua, coordenadas polares e integração de várias variáveis. Como aplicações deste estudo temos os casos das distribuições de probabilidade uniforme e normal. Um terceiro problema tratado foi o seguinte: no espaço tridimensional temos uma fonte de emissão T, por exemplo, algum gerador de campo magnético, a qual distribui uniformemente sua energia até um raio a. Suponha, dada uma partícula num ponto P do espaço. Se tal partícula se deslocar aleatoriamente um raio igual a b qual é a probabilidade dela entrar na zona de influência da fonte de emissão T? Neste problema usamos coordenadas esféricas, integral de superfície e distribuição de probabilidade continua para o seu estudo. Também, aplicamos aos casos de distribuição de probabilidade uniforme e normal / Abstract: In our view, Geometric Probability quantifies the probability of occurs some phenomena associated with geometric entities. The first study, perhaps the most famous, to be performed of this type is the problem of Buffon's needle. The idea of this study is simple. Two parallel lines drawn at a distance d, which is the probability that a needle of length l achieve one of the straights? In this work we decided initially to study this problem and its resolution. A second topic of our study was based on the following problem: Suppose an antenna transmitting a signal, eg mobile, send their signals uniformly until a distance a in a plane. If I'm at a point P of the plane, which is the probability to enter the zone of emission signal from the antenna if I move up to a radius b? To solve this problem we use continuous probability, polar coordinates and integration of several variables. As applications of this study we have the cases of probability distributions, uniform and normal. A third problem approached was the following: in a three-dimensional space we have an emission source T, for example, a magnetic field generator, which evenly distributes its energy up to a radius a. Given a particle at a point P in space. If this particle moves randomly a radius equal to b what is the probability of it entering the zone of influence of the emission source T? In this problem we use spherical coordinates, surface integral and continuous probability distribution for its study. Also apply to cases of uniform and normal probability distribution / Mestrado / Matematica / Mestre em Matemática
487

Modelos de transição de Markov: um enfoque em experimentos planejados com dados binários correlacionados / Markov transition models: a focus on planned experiments with correlated binary data

Mauricio Santana Lordelo 30 May 2014 (has links)
Os modelos de transição de Markov constituem uma ferramenta de grande importância para diversas áreas do conhecimento quando são desenvolvidos estudos com medidas repetidas. Eles caracterizam-se por modelar a variável resposta ao longo do tempo condicionada a uma ou mais respostas anteriores, conhecidas como a história do processo. Além disso, é possível a inclusão de outras covariáveis. No caso das respostas binárias, pode-se construir uma matriz com as probabilidades de transição de um estado para outro. Neste trabalho, quatro abordagens diferentes de modelos de transição foram comparadas para avaliar qual estima melhor o efeito causal de tratamentos em um estudo experimental em que a variável resposta é um vetor binário medido ao longo do tempo. Estudos de simulação foram realizados levando em consideração experimentos balanceados com três tratamentos de natureza categórica. Para avaliar as estimativas foram utilizados o erro padrão, viés e percentual de cobertura dos intervalos de confiança. Os resultados mostraram que os modelos de transição marginalizados são mais indicados na situação em que um experimento é desenvolvido com um reduzido número de medidas repetidas. Como complementação, apresenta-se uma forma alternativa de realizar comparações múltiplas, uma vez que os pressupostos como normalidade, independência e homocedasticidade são violados impossibilitando o uso dos métodos tradicionais. Um experimento com dados reais no qual se registrou a presença de fungos (considerada como sucesso) em cultivos de citros e morango foi analisado por meio do modelo de transição apropriado. Para as comparações múltiplas, intervalos de confiança simultâneos foram construídos para o preditor linear e os resultados foram estendidos para a resposta média que neste caso são as probabilidades de sucesso. / The transition Markov models are a very important tool for several areas of knowledge when studies are developed with repeated measures. They are characterized by modeling the response variable over time conditional to the previous response which is known as the history. In addtion it is possible to include other covariates. In the case of binary responses, can be constructed a matrix of transition probabilities from one state to another. In this work, four different approaches to transition models were compared in order to assess which best estimates of the causal effect of treatments in an experimental studies where the outcome is a vector of binary response measured over time. Simulation study was held taking into account a balanced experiments with three treatments of categorical nature. To assess the best estimates standard error and bias, beyond the percentage of coverage were used. The results showed that the marginalized transition models are more appropriate in situation where an experiment is developed with a reduced number of repeated measurements. As complementation is presented an alternative way to perform multiple comparisons, since the assumptions as normality, independence and homoscedasticity are violated precluding the use of traditional methods. An experiment with real data where we recorded the presence of fungi (deemed successful) in citrus and strawberry crops was analyzed through the appropriate transition model. For multiple comparisons, simultaneous confidence intervals were constructed for the linear predictor and the results have been extended to the mean response in this case are the probabilities of success.
488

Cadeias de Markov: uma aula para alunos do ensino médio

Rodrigues, Welton Carlos 09 August 2013 (has links)
Submitted by isabela.moljf@hotmail.com (isabela.moljf@hotmail.com) on 2016-08-17T15:42:43Z No. of bitstreams: 1 weltoncarlosrodrigues.pdf: 758210 bytes, checksum: 9c15820809534ca120157f528ea72c27 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2016-08-18T11:48:29Z (GMT) No. of bitstreams: 1 weltoncarlosrodrigues.pdf: 758210 bytes, checksum: 9c15820809534ca120157f528ea72c27 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2016-08-18T11:53:32Z (GMT) No. of bitstreams: 1 weltoncarlosrodrigues.pdf: 758210 bytes, checksum: 9c15820809534ca120157f528ea72c27 (MD5) / Made available in DSpace on 2016-08-18T11:53:32Z (GMT). No. of bitstreams: 1 weltoncarlosrodrigues.pdf: 758210 bytes, checksum: 9c15820809534ca120157f528ea72c27 (MD5) Previous issue date: 2013-08-09 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Esta dissertação tem como objetivo principal apresentar os conceitos básicos das cadeias de Markov, uma teoria pouco explorada no ensino básico e que é bastante útil na tomada de decisões futuras. Como esses processos de Markov utilizam dois importantes conteúdos de matemática, probabilidades e matrizes, permite-se também um complemento para esses estudos. / This master thesis’ main objective is to present the basic concepts of Markov chains, a theory underexplored on basic education, which is a very useful instrument on taking decisions. The study of Markov processes also helps students deepen their understanding of matrices and probabilities.
489

Co-Evolution of Information Revolution and Spread of Democracy. 33. Jahrestagung der Gesellschaft für Informatik an der Johann Wolfgang Goethe-Universität in Frankfurt am Main 29.9. - 2.10. 2003

Frisch, Walter 29 September 2003 (has links) (PDF)
This is a short summary of a recent survey [FR03] focusing on the observed evidence, that Internet connectivity is positively correlated with spread of democracy at high levels of significance. The results of multivariate correlation analysis and probabilities regression estimate models are based on the combined analysis of mid - 1991's, to 2001 data series of the Eurostat's and US Census Bureau, the World Bank, and OECD's statistical data service which track the growth of information technology and rating of freedom and democracy worldwide.(author's abstract)
490

Évolution de l’architecture des génomes : modélisation et reconstruction phylogénétique / Evolution of the architecture of genomes : modelling and phylogenetic reconstruction

Semeria, Magali 09 December 2015 (has links)
L'évolution des génomes peut être observée à plusieurs échelles, chaque échelle révélant des processus évolutifs différents. A l'échelle de séquences ADN, il s'agit d'insertions, délétions et substitutions de nucléotides. Si l'on s'intéresse aux gènes composant les génomes, il s'agit de duplications, pertes et transferts horizontaux de gènes. Et à plus large échelle, on observe des réarrangements chromosomiques modifiant l'agencement des gènes sur les chromosomes. Reconstruire l'histoire évolutive des génomes implique donc de comprendre et de modéliser tous les processus à l'œuvre, ce qui reste hors de notre portée. A la place, les efforts de modélisation ont exploré deux directions principales. D'un côté, les méthodes de reconstruction phylogénétique se sont concentrées sur l'évolution des séquences, certaines intégrant l'évolution des familles de gènes. D'un autre côté, les réarrangements chromosomiques ont été très largement étudiés, donnant naissance à de nombreux modèles d'évolution de l'architecture des génomes. Ces deux voies de modélisation se sont rarement rencontrées jusqu'à récemment. Au cours de ma thèse, j'ai développé un modèle d'évolution de l'architecture des génomes prenant en compte l'évolution des gènes et des séquences. Ce modèle rend possible une reconstruction probabiliste de l'histoire évolutive d'adjacences et de l'ordre des gènes de génomes ancestraux en tenant compte à la fois d'évènements modifiant le contenu en gènes des génomes (duplications et pertes de gènes), et d'évènements modifiant l'architecture des génomes (les réarrangements chromosomiques). Intégrer l'information phylogénétique à la reconstruction d'ordres des gènes permet de reconstruire des histoires évolutives plus complètes. Inversement, la reconstruction d'ordres des gènes ancestraux peut aussi apporter une information complémentaire à la phylogénie et peut être utilisée comme un critère pour évaluer la qualité d'arbres de gènes, ouvrant la voie à un modèle et une reconstruction intégrative / Genomes evolve through processes that modify their content and organization at different scales, ranging from the substitution, insertion or deletion of a single nucleotide to the duplication, loss or transfer of a gene and to large scale chromosomal rearrangements. Extant genomes are the result of a combination of many such processes, which makes it difficult to reconstruct the overall picture of genome evolution. As a result, most models and methods focus on one scale and use only one kind of data, such as gene orders or sequence alignments. Most phylogenetic reconstruction methods focus on the evolution of sequences. Recently, some of these methods have been extended to integrate gene family evolution. Chromosomal rearrangements have also been extensively studied, leading to the development of many models for the evolution of the architecture of genomes. These two ways to model genome evolution have not exchanged much so far, mainly because of computational issues. In this thesis, I present a new model of evolution for the architecture of genomes that accounts for the evolution of gene families. With this model, one can reconstruct the evolutionary history of gene adjacencies and gene order accounting for events that modify the gene content of genomes (duplications and losses of genes) and for events that modify the architecture of genomes (chromosomal rearrangements). Integrating these two types of information in a single model yields more accurate evolutionary histories. Moreover, we show that reconstructing ancestral gene orders can provide feedback on the quality of gene trees thus paving the way for an integrative model and reconstruction method

Page generated in 0.0893 seconds