• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 3
  • 2
  • 1
  • 1
  • Tagged with
  • 7
  • 7
  • 3
  • 3
  • 3
  • 3
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 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.
1

Modélisation spatiale de valeurs extrêmes : application à l'étude de précipitations en France / Spatial modeling of extreme values. Application to precipitation in France

Sebille, Quentin 01 December 2016 (has links)
Les précipitations extrêmes en France sont responsables de phénomènes d'inondations entraînant la perte de vies humaines et des millions d'euros en dégâts matériels. Mesurer le risque associé à ces événements météorologiques rares fait appel à la théorie statistique des valeurs extrêmes, qui propose plusieurs approches permettant d'évaluer des scénarios catastrophes. Cette thèse s'intéresse en particulier à trois mesures de risque faisant intervenir à la fois des lois de probabilité jointes et des méthodes de prédiction spatiale liées à la géostatistique.Dans un premier temps, plusieurs modèles spatiaux de valeurs extrêmes construits sur des données de maxima annuels sont évalués dans une étude comparative sous la forme d'un article. La comparaison des méthodes est menée en se servant de simulations construites à partir de données réelles de maxima annuels de précipitations en France et porte sur des critères liés aux deux mesures de risque que sont le niveau de retour centennal et le coefficient extrémal.Un modèle en particulier, le processus max-stable et hiérarchique de Reich et Shaby (2012) est étudié en détail et fait l'objet d'une implémentation sous la forme d'un package R dédié à la simulation et à l'estimation par cette méthode.Dans un second temps, les données journalières dépassant un seuil élevé sont modélisées dans un cadre spatial dans le but d'estimer une probabilité d'échec conditionnelle. Plusieurs estimateurs de cette mesure sont proposés en se concentrant d'une part sur des méthodes paramétriques liées aux processus Pareto et d'autre part sur deux approches non paramétriques. Les méthodes sont construites de sorte que la dépendance temporelle observable dans les valeurs journalière soit prise en compte lors de l'estimation.Tout au long de la thèse, les méthodes développées sont appliquées sur des données journalières de précipitations en France / Extreme precipitation in France are responsible for flooding events that cause people's deaths and billions of euros in material damage. Measuring the risk associated to these rare meteorological events is possible thanks to the extreme value theory which allows the estimation of such catastrophic scenarios. This thesis focus on three risk measures involving joint probabilities and spatial prediction methods related to geostatistics.In a first time, several spatial models for extreme values built on annual maxima are evaluated in a comparative study in the form of an article. This comparison is performed using simulated data from real annual maxima of precipitation in France. It is also based on two criteria linked to risk measures: the hundred years return level and the extremal coefficient. One particular model is presented in details: the one of Reich and Shaby (2012). This model is implemented under a R package entirely dedicated to its estimation and simulation procedures.In a second time, exceedances of spatial daily data are modelled in order to estimate a conditional failure probability. Several estimators of this measure are proposed, based on the one hand on parametric methods involving Pareto processes and on the other hand on non parametric approaches. The temporal dependence in extremes is also considered with care when estimating this probability.Along this thesis, the methods are applied on daily data of precipitation in France
2

Cidades outras: pobreza, moradia e mediações em trajetórias urbanas liminares / Other cities: poverty, housing and mediations in liminar urban trajectories

Rosa, Thaís Troncon 25 November 2014 (has links)
Inserindo-se nos debates sobre pobreza e cidade no Brasil, a pesquisa aborda os nexos entre deslocamentos habitacionais, mobilidades socioespaciais, dinâmicas familiares e políticas urbanas nos processos recentes de produção do espaço urbano. A tese parte do argumento de que, em um contexto de reconfiguração do mundo social e ressignificação das categorias fundadoras dos territórios periféricos, em curso no país nas últimas décadas, também o espaço urbano se reconfigura: nesse sentido, direciona-se a refletir, de modo articulado, sobre as dimensões sociais e territoriais dessas mudanças e permanências. Tomando como base a realização de uma pesquisa de campo de caráter etnográfico na cidade de São Carlos - SP, são investigadas trajetórias urbanas de moradores de periferias que, nas últimas décadas, transitaram pela cidade em busca de moradia, bem como os cruzamentos, tangenciamentos ou desencontros com as políticas urbanas e habitacionais empreendidas nesse mesmo período. Tais trajetórias são encaradas como uma entrada privilegiada para o estudo das dinâmicas socioespaciais envolvidas em processos situados de produção, apropriação e significação das periferias urbanas, ao permitir apreender tais processos nas injunções entre espaço e sociedade. A tese delineia uma cartografia espaço-temporal de territorialidades e experiências urbanas ditas marginais ou periféricas, revelando cidades outras: cidades feitas de desenraizamentos, vulnerabilidades e ajustes, mas também de relações, simbolizações e projetos, cuja multiplicidade de dimensões históricas, concepções em ato ou devires possíveis somente se dão a apreender a partir das práticas e narrativas dos sujeitos. Estabelece, assim, um diálogo sobre as dobras que configuram, simultaneamente, territórios, subjetividades e sensibilidades; percursos, narrativas e espaços; pobreza, experiência urbana e cidades; produção de conhecimento e produção do espaço. / Being inserted in debates about poverty and cities in Brazil, the research deals with the links among housing displacements, socio-spatial mobility, family dynamics and urban policies in recent processes of urban space production. The dissertation starts from the argument that, in the context of reconfiguration of the social world and re-signification of the founding categories of surrounding territories, in progress in the country in recent decades, the urban space is also reconfigured: in this sense, it is directed to reflect, in an articulated way, about social and territorial dimensions of these changes and continuities. Based on the completion of an ethnographic field research in the city of São Carlos - SP, it investigates urban trajectories of residents of surrounding areas who, over the last decades, passed through the city in search of housing, as well as the crossings, tangents or divergences with the urban and housing policies undertaken during the same period. Such trajectories are faced as a prime input for the study of socio-spatial dynamics involved in situated processes of production, appropriation and significance of urban surrounding areas, while allowing for apprehending such processes in the injunctions between space and society. The dissertation outlines a spatio-temporal cartography of urban territorialities and experiences considered marginal or peripheral, revealing other cities: cities made out of uprooting, vulnerabilities and adjustments, but also of relationships, symbolizations and projects, whose multiplicity of historical dimensions, conceptions in act or possible future ones, take place just to be apprehended as from the practices and narratives of the subjects. A dialogue is thus established on the folds that simultaneously shape territories, subjectivities and sensibilities; pathways, narratives and spaces; poverty, urban experience and cities; production of knowledge and production of space.
3

Cidades outras: pobreza, moradia e mediações em trajetórias urbanas liminares / Other cities: poverty, housing and mediations in liminar urban trajectories

Thaís Troncon Rosa 25 November 2014 (has links)
Inserindo-se nos debates sobre pobreza e cidade no Brasil, a pesquisa aborda os nexos entre deslocamentos habitacionais, mobilidades socioespaciais, dinâmicas familiares e políticas urbanas nos processos recentes de produção do espaço urbano. A tese parte do argumento de que, em um contexto de reconfiguração do mundo social e ressignificação das categorias fundadoras dos territórios periféricos, em curso no país nas últimas décadas, também o espaço urbano se reconfigura: nesse sentido, direciona-se a refletir, de modo articulado, sobre as dimensões sociais e territoriais dessas mudanças e permanências. Tomando como base a realização de uma pesquisa de campo de caráter etnográfico na cidade de São Carlos - SP, são investigadas trajetórias urbanas de moradores de periferias que, nas últimas décadas, transitaram pela cidade em busca de moradia, bem como os cruzamentos, tangenciamentos ou desencontros com as políticas urbanas e habitacionais empreendidas nesse mesmo período. Tais trajetórias são encaradas como uma entrada privilegiada para o estudo das dinâmicas socioespaciais envolvidas em processos situados de produção, apropriação e significação das periferias urbanas, ao permitir apreender tais processos nas injunções entre espaço e sociedade. A tese delineia uma cartografia espaço-temporal de territorialidades e experiências urbanas ditas marginais ou periféricas, revelando cidades outras: cidades feitas de desenraizamentos, vulnerabilidades e ajustes, mas também de relações, simbolizações e projetos, cuja multiplicidade de dimensões históricas, concepções em ato ou devires possíveis somente se dão a apreender a partir das práticas e narrativas dos sujeitos. Estabelece, assim, um diálogo sobre as dobras que configuram, simultaneamente, territórios, subjetividades e sensibilidades; percursos, narrativas e espaços; pobreza, experiência urbana e cidades; produção de conhecimento e produção do espaço. / Being inserted in debates about poverty and cities in Brazil, the research deals with the links among housing displacements, socio-spatial mobility, family dynamics and urban policies in recent processes of urban space production. The dissertation starts from the argument that, in the context of reconfiguration of the social world and re-signification of the founding categories of surrounding territories, in progress in the country in recent decades, the urban space is also reconfigured: in this sense, it is directed to reflect, in an articulated way, about social and territorial dimensions of these changes and continuities. Based on the completion of an ethnographic field research in the city of São Carlos - SP, it investigates urban trajectories of residents of surrounding areas who, over the last decades, passed through the city in search of housing, as well as the crossings, tangents or divergences with the urban and housing policies undertaken during the same period. Such trajectories are faced as a prime input for the study of socio-spatial dynamics involved in situated processes of production, appropriation and significance of urban surrounding areas, while allowing for apprehending such processes in the injunctions between space and society. The dissertation outlines a spatio-temporal cartography of urban territorialities and experiences considered marginal or peripheral, revealing other cities: cities made out of uprooting, vulnerabilities and adjustments, but also of relationships, symbolizations and projects, whose multiplicity of historical dimensions, conceptions in act or possible future ones, take place just to be apprehended as from the practices and narratives of the subjects. A dialogue is thus established on the folds that simultaneously shape territories, subjectivities and sensibilities; pathways, narratives and spaces; poverty, urban experience and cities; production of knowledge and production of space.
4

On Parametric and Nonparametric Methods for Dependent Data

Bandyopadhyay, Soutir 2010 August 1900 (has links)
In recent years, there has been a surge of research interest in the analysis of time series and spatial data. While on one hand more and more sophisticated models are being developed, on the other hand the resulting theory and estimation process has become more and more involved. This dissertation addresses the development of statistical inference procedures for data exhibiting dependencies of varied form and structure. In the first work, we consider estimation of the mean squared prediction error (MSPE) of the best linear predictor of (possibly) nonlinear functions of finitely many future observations in a stationary time series. We develop a resampling methodology for estimating the MSPE when the unknown parameters in the best linear predictor are estimated. Further, we propose a bias corrected MSPE estimator based on the bootstrap and establish its second order accuracy. Finite sample properties of the method are investigated through a simulation study. The next work considers nonparametric inference on spatial data. In this work the asymptotic distribution of the Discrete Fourier Transformation (DFT) of spatial data under pure and mixed increasing domain spatial asymptotic structures are studied under both deterministic and stochastic spatial sampling designs. The deterministic design is specified by a scaled version of the integer lattice in IRd while the data-sites under the stochastic spatial design are generated by a sequence of independent random vectors, with a possibly nonuniform density. A detailed account of the asymptotic joint distribution of the DFTs of the spatial data is given which, among other things, highlights the effects of the geometry of the sampling region and the spatial sampling density on the limit distribution. Further, it is shown that in both deterministic and stochastic design cases, for "asymptotically distant" frequencies, the DFTs are asymptotically independent, but this property may be destroyed if the frequencies are "asymptotically close". Some important implications of the main results are also given.
5

Configurando a cidade contempor?nea em Natal : os processos espaciais em Ponta Negra

Fechine, Eleika Rochelle de Carvalho Bezerra 09 November 2011 (has links)
Made available in DSpace on 2014-12-17T13:57:04Z (GMT). No. of bitstreams: 1 EleikaRCB_DISSERT.pdf: 6181790 bytes, checksum: eb403e6ca4bd1efd6820ce95d2a4eeed (MD5) Previous issue date: 2011-11-09 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / This dissertation is about the spatial configuration in Natal and processes in the Ponta Negra neighborhood today. Ponta Negra has undergone a number of critical social and spatial changes due to tourism development after the 1990s. It is of special interest to consider the intensification of real estate investment after 2000, when the new airport terminal, located in the neighboring municipality of Parnamirim, was in use. Ponta Negra is the place where most tourists go to, so attracting considerable public investments. New agents of transformation have produced change in the neighborhood as well. The present study aims at analysing the spatial processes in this part of the city. Here, the spatial configuration that resulted from extended real estate investments, both public and private, in recent years, is analysed in detail. The study identifies the multually differentiated, however internally homogenous areas. The concepts of production of space, contemporanean urban development and spatial dynamics are discussed. The research is based on document analysis and field work. Results were plotted to maps and tables. A detailed analysis of the spatial processes in the Ponta Negra neighborhood is undertaken as a conclusion, considering the contemporanean global scenario / A presente disserta??o trata da configura??o do espa?o contempor?neo em Natal e os processos espaciais de Ponta Negra. O bairro de Ponta Negra sofreu, com a emerg?ncia do turismo, mudan?as espaciais e sociais a partir da d?cada de 1990, em particular considerando a intensifica??o de investimentos imobili?rios a partir do marco temporal de 2000, devido ao in?cio do funcionamento do novo terminal de passageiros do aeroporto Augusto Severo. Ponta Negra configura-se ent?o como maior ponto de recep??o, de lazer e aloca??o de investimentos p?blicos de Natal. Assim, produzem modifica??es no bairro, novos agentes da produ??o do espa?o. O presente estudo tem por objeto os novos processos espaciais no bairro de Ponta Negra. Aqui, analisar-se a configura??o resultante dos novos investimentos imobili?rios, p?blicos e privados, realizados no bairro nos ?ltimos anos, identificando a exist?ncia de ?reas que, embora homog?neas, s?o diferenciadas entre si. Tr?s grandes discuss?es te?ricas Produ??o do Espa?o Capitalista, Desenvolvimento Urbano Contempor?neo e Din?mica Espacial d?o suporte ao trabalho, al?m da pesquisa documental e de campo (levantamento de uso e ocupa??o do solo e levantamento fotogr?fico), transportada para mapas tem?ticos interpretativos e tabelas. Conclu?mos a pesquisa, com a an?lise detalhada dos processos espaciais do bairro de Ponta Negra sob a influ?ncia de processos globais contempor?neos
6

The autotelic experience : a design approach to user experience

Lesage, Annemarie 04 1900 (has links)
Si les principes d’utilisabilité guident la conception de solutions de design interactif pour s’assurer que celles-ci soient « utilisables », quels principes guident la conception d’objets interactifs pour s’assurer que l’expérience subjective de l’usager (UX) soit adéquate et mémorable? Que manque-t-il au cadre de l‘UX pour expliquer, comprendre, et anticiper en tant que designer une expérience mémorable (‘an experience’; Dewey, 1934)? La question centrale est issue d’une double problématique : (1) le cadre théorique de l’UX est incomplet, et (2) les processus et capacités des designers ne sont pas considérés et utilisés à leur pleine capacité en conception UX. Pour répondre à cette question, nous proposons de compléter les modèles de l’UX avec la notion d’expérience autotélique qui appartient principalement à deux cadres théoriques ayant bien cerné l’expérience subjective, soit l’expérience optimale (ou Flow) de Csikszentmihalyi (1988) et l’expérience esthétique selon Schaeffer (2001). L’autotélie est une dimension interne du Flow alors qu’elle couvre toute l’expérience esthétique. L’autotélie est une expérience d’éveil au moment même de l’interaction. Cette prise de conscience est accompagnée d’une imperceptible tension de vouloir faire durer ce moment pour faire durer le plaisir qu’il génère. Trois études exploratoires ont été faites, s’appuyant sur une analyse faite à partir d’un cadre théorique en trois parties : le Flow, les signes d’activité non verbale (les gestes physiques) et verbale (le discours) ont été évalués pour voir comment ceux-ci s’associent. Nos résultats tendent à prouver que les processus spatiaux jouent un rôle de premier plan dans l’expérience autotélique et par conséquent dans une UX optimale. De plus, ils suggèrent que les expériences pragmatique et autotélique sont ancrées dans un seul et même contenu, et que leur différence tient au type d’attention que le participant porte sur l’interaction, l’attention ordinaire ou de type autotélique. Ces résultats nous ont menés à proposer un modèle pour la conception UX. L’élément nouveau, resté jusqu’alors inaperçu, consiste à s’assurer que l’interface (au sens large) appelle une attitude réceptive à l’inattendu, pour qu’une information puisse déclencher les processus spatiaux, offrant une opportunité de passer de l’attention ordinaire à l’attention autotélique. Le nouveau modèle ouvre la porte à une meilleure valorisation des habiletés et processus du designer au sein de l’équipe multidisciplinaire en conception UX. / If usability guides the formal organisation of interactive systems as it pertains to being usable, useful and efficient, what principle(s) guide(s) the formal organisation of interactive systems when it comes to give form to the subjective dimension of the user experience? This question came from two perceived gaps in our understanding of UX: (1) the UX theoretical framework appears incomplete to this day. Going beyond experiencing, what is at play during Dewey’s an experience? (2) The process and abilities of designers are underused in the current theoretical and practical UX framework; what would provide a more designerly approach? We propose that the autotelic experience could bridge these gaps and be the UX counterpart to usability. The autotelic experience is an internal dimension at the heart of the optimal experience—Flow—(Csikszentmihalyi, 1975) and covering the whole of the aesthetic experience (Schaeffer, 2000). The autotelic experience is a shift in awareness occurring during the interaction. This awareness is accompanied by an imperceptible tension of wanting to make this moment last in order to continue enjoying the pleasure it generates (a circular motivation to stay in the interaction for the sake of the interaction itself) (Schaeffer, 2000). Our results suggest the key to the autotelic experience sits with visuospatial reasoning or more specifically to right hemisphere (RH) activation. Three exploratory studies were conducted, using a three-part theoretical framework where Flow, signs of nonverbal / spatial activity (physical gestures) and of verbal activity (discourse) were assessed for their various associations. The main contribution of this research is a model of autotelic experience made of three interlocking elements (high positive pressure, low mental demand and an openness to unexpected events) contextualised by either an active or a receptive engagement on the part of the user. One of the findings is that the pragmatic experience and the autotelic experience (which we have associated to Dewey’s an experience, 1934), are based on one and the same content, the only difference is the shift in attention on the participant’s part. All the elements of the model are known, but one, to design the experience in a way to keep the user open to the unexpected. This one element supports the occurrence of the shift from ordinary to autotelic attention. The new model opens the door to a better appreciation of designers’ skills and processes within multidisciplinary team in UX design.
7

Étude de modèles spatiaux et spatio-temporels / Spatial and spatio-temporal models and application

Cisse, Papa Ousmane 11 December 2018 (has links)
Ce travail porte sur les séries spatiales. On étudie les phénomènes dont l’observation est un processus aléatoire indexé par un ensemble spatial. Dans cette thèse on s’intéresse aux données bidimensionnelles régulièrement dispersées dans l’espace, on travaille alors dans un rectangle régulier (sur Z2) . Cette modélisation vise donc à construire des représentations des systèmes suivant leurs dimensions spatiales et à ses applications dans de nombreux domaines tels que la météorologie, l’océanographie, l’agronomie, la géologie, l’épidémiologie, ou encore l’économétrie etc. La modélisation spatiale permet d’aborder la question importante de la prédiction de la valeur d’un champ aléatoire en un endroit donné d’une région. On suppose que la valeur à prédire dépend des observations dans les régions voisines. Ceci montre la nécessité de tenir compte, en plus de leurs caractéristiques statistiques, des relations de dépendance spatiale entre localisations voisines, pour rendre compte de l’ensemble des structures inhérentes aux données. Dans la plupart des champs d’applications, on est souvent confronté du fait que l’une des sources majeures de fluctuations est la saisonnalité. Dans nos travaux on s’intéresse particulièrement à ce phénomène de saisonnalité dans les données spatiales. Faire une modélisation mathématique en tenant en compte l’interaction spatiale des différents points ou localités d’une zone entière serait un apport considérable. En effet un traitement statistique qui prendrait en compte cet aspect et l’intègre de façon adéquat peut corriger une perte d’information, des erreurs de prédictions, des estimations non convergentes et non efficaces. / This thesis focuses on the time series in addition to being observed over time, also have a spatial component. By definition, a spatiotemporal phenomenon is a phenomenon which involves a change in space and time. The spatiotemporal model-ling therefore aims to construct representations of systems taking into account their spatial and temporal dimensions. It has applications in many fields such as meteorology, oceanography, agronomy, geology, epidemiology, image processing or econometrics etc. It allows them to address the important issue of predicting the value of a random field at a given location in a region. Assume that the value depends predict observations in neighbouring regions. This shows the need to consider, in addition to their statistical characteristics, relations of spatial dependence between neighbouring locations, to account for all the inherent data structures. In the exploration of spatiotemporal data, refinement of time series models is to explicitly incorporate the systematic dependencies between observations for a given region, as well as dependencies of a region with neighboring regions. In this context, the class of spatial models called spatiotemporal auto-regressive models (Space-Time Autoregressive models) or STAR was introduced in the early 1970s. It will then be generalized as GSTAR model (Generalized Space-Time Autoregressive models). In most fields of applications, one is often confronted by the fact that one of the major sources of fluctuations is seasonality. In our work we are particularly interested in the phenomenon of seasonality in spatiotemporal data. We develop a new class of models and investigates the properties and estimation methods. Make a mathematical model taking into account the spatial inter-action of different points or locations of an entire area would be a significant contribution. Indeed, a statistical treatment that takes into account this aspect and integrates appropriate way can correct a loss of information, errors in predictions, non-convergent and inefficient estimates.

Page generated in 0.0726 seconds