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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.
311

A regularização fundiária no Parque Nacional da Serra da Canastra e a expropriação camponesa: da baioneta à ponta da caneta / Land regularization in the National Park of the Serra da Canastra and peasantry expropriation: from the bayonet to the pen tip

Gustavo Henrique Cepolini Ferreira 17 September 2013 (has links)
A regularização fundiária no Brasil está engendrada nas contradições do modo capitalista de produção, as quais impulsionam os conflitos e disputas territoriais no campo como uma das marcas do desenvolvimento e da ocupação territorial no país. A partir dessa premissa, essa pesquisa visa analisar o histórico do Parque Nacional da Serra da Canastra (PNSC), localizado na região sudoeste de Minas Gerais, reconhecendo o encontro e desencontro da luta pela terra e as Unidades de Conservação (UC) no país, assim como procura desvendar as irregularidades e pressupostos que nortearam a implantação dessa UC através do Decreto Federal de 1972 e as diferentes estratégias para regularizar o PNSC desde então. Nesse contexto, os camponeses - sujeitos sociais do território da Canastra sofreram expropriações e restrições em função do modelo de conservação sem pessoas, apregoado predominantemente nas políticas públicas. Por isso, as disputas entre territorialidades, aumentam constantemente sob discursos antagônicos, os quais resultam em propostas que afetam diretamente o modo de vida camponês ao favorecer a conservação ambiental (leia-se sem pessoas), a mineração e mais recentemente o próprio agronegócio. Nesse sentido, as estratégias para regularização fundiária do PNSC agravam as tensões entre territorialidades e mantêm inúmeras famílias camponesas com o futuro incerto na Canastra, restando-lhes resistir na terra de trabalho e vida. / The landing regularization in Brazil is tangled in contradictions of the production capitalist way which thrive the conflicts and land disputes in the rural area as a mark of the countrys development and land occupation. From this premise, this research aims to analyse the history of the National Park of the Serra da Canastra (PNSC), located in the southest region of Minas Gerais, not only recognizing the rights and wrongs of the fight for the land and for the Conservation Units (UC) in the country but also this research seeks to unveil the irregularities and the objectives which aimed the implantation of this UC through the Federal decree of 1972 and the different strategies to regulate the NPSC from that. In this context, the peasants - social subjects of Canastra land suffered expropriations and restrictions due to the model of conservations without people, based predominantly on the public policies. Thats why the disputes between lands increased constantly under antagonic discourses which resulted on proposals which affected directly on the peasant lifestyle for favoring the environment conservation (without people), the mining e more recently the agribusiness. On this way, the strategies for landing regularization of the PNSC worsen the tensions between lands disputers and give a number of peasant families a uncertain future on the Canastra, leaves them to struggle on the land and life.
312

Programa de regularização fundiária sustentável de assentamentos irregulares de São Bernardo do Campo: avanços e desafios ao processo de regularização fundiária no âmbito da política habitacional municipal / Program of sustainable environmental regularization of irregular settings of São Bernardo do Campo: advances and challenges to the process of environmental regularization in the framework of municipal housing policy

Tatiana Urbanovik Brandimiller 19 April 2017 (has links)
A pesquisa pretende identificar e analisar criticamente os avanços trazidos e os desafios enfrentados na implementação do Programa de Regularização Fundiária Sustentável no município de São Bernardo do Campo, estado de São Paulo. Ao abordar a regularização fundiária, a pesquisa busca compreender o seu papel como política pública estratégica na promoção do acesso à moradia e à cidade por parte da população de baixa renda. A intenção do trabalho é contribuir para construção de um panorama crítico às diferentes compreensões e proposições de atuação sobre a Regularização Fundiária de Interesse Social. Para tanto, problematiza a questão em suas diversas acepções e concepções, abordando criticamente e relacionando-a às diferentes correntes de pensamento sobre o tema. Além do aporte conceitual e da literatura específica, contribui para a pesquisa as experiências profissionais vividas pela autora ao longo dos últimos cinco anos na implementação dessa política pública no município de São Bernardo do Campo. / The research aims to critically identify and analyse the advances brought and the challenges faced in the implementation of a Sustainable Land Tenure Regularization Program in the municipality of São Bernardo do Campo, state of São Paulo. When addressing land tenure regularization, the research seeks to understand its role as a public policy strategic in the promotion of access to housing and to the city by the low-income population. The intention of the paper is to contribute to the construction of a panorama critical to the different understandings and propositions of action about the Land Tenure Regularization of Social Interest. To do so, it problematizes the issue in its various meanings and conceptions, critically approaching and relating it to the different lines of thought on the subject. Besides the conceptual addition and specific literature, contributes to the research the professional experiences of the author over the past five years in the implementation of this public policy in the municipality of São Bernardo do Campo.
313

Metodologia para determinação de vazões de restrição com suporte de análise multicriterial = estudo de caso na UHE Barra Bonita no Rio Tietê-SP / Methodology for determination of flow restriction in hydroelectric power plants with support of multicriteria analysis : case study in the HPP Barra Bonita on the Rio Tietê-SP

Basseto, Eduardo Antonio Pires, 1974- 21 August 2018 (has links)
Orientador: Alberto Luiz Francato / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Civil, Arquitetura e Urbanismo / Made available in DSpace on 2018-08-21T04:45:20Z (GMT). No. of bitstreams: 1 Basseto_EduardoAntonioPires_M.pdf: 1967825 bytes, checksum: 335fd48e7fdd853205200ce11fdb1859 (MD5) Previous issue date: 2012 / Resumo: O trabalho apresenta uma metodologia de hierarquização do grau de proteção contra cheias a jusante de reservatórios de usinas hidroelétricas, em função de diferentes vazões de restrição (QR) e períodos de retorno (TR). A escolha das melhores alternativas de especificação do par (QR,TR) é feita por meio de otimização multiobjetivo. A medida do impacto da violação da vazão de restrição é traduzida na forma de funções de penalidade. A metodologia proposta foi testada em um estudo de caso na usina hidrelétrica de Barra Bonita, no rio Tietê. Tal estudo revelou a adequação da metodologia proposta, onde se fez uma investigação simultânea do par (QR,TR) para avaliação dos volumes de espera associados / Abstract: The paper presents a methodology to rank the degree of protection against flooding downstream reservoirs of hydroelectric plants, for different flow restriction (QR) and return periods (TR). The choice of the best alternative specification pair (QR, TR) is made by means of multiobjective optimization. The extent of the impact of the breach flow restriction is translated in the form of penalty functions. The proposed methodology was tested in a case study in Bonita hydroelectric plant on the river Tietê. This study revealed the suitability of the proposed methodology, where we make a simultaneous investigation of the pair (QR, TR) to avaliate the associated expected volumes / Mestrado / Recursos Hidricos, Energeticos e Ambientais / Mestre em Engenharia Civil
314

Une situation de « post-front pionnier » : le cas de la region rurale de Ciriaco (Maranhão - Brésil) / A 'post pioneer' situation : the case of the rural region of Ciriaco (West Maranhão – Brazil)

Nasuti, Stéphanie-Caroline 09 June 2010 (has links)
Cette étude présente les composantes spatio-temporelles ayant structuré une région d’arrière-front pionnier de la frange orientale de l’Amazonie brésilienne [pré-Amazonie maranhense, Imperatriz]. Afin de saisir les conditions d’organisation du peuplement, nous cartographions les trajectoires migratoires de la première génération ayant afflué massivement dans les années soixante, que nous comparons aux actuelles stratégies de circulation des jeunes générations. L’évolution foncière, inhérente à la consolidation d’un front pionnier, s’est singularisée par diverses interventions directes de l’Etat fédéral, privilégiant tour à tour la régularisation individuelle pour rétablir la paix sociale [Getat] puis l’usufruit collectif des terres pour préserver l’environnement [aires protégées]. Nous avons reconstitué les étapes de la chaîne foncière, montrant dans quelles conditions des petits agriculteurs ont pu accéder durablement à la propriété jusqu’à l’implantation d’une réserve extractiviste, Ciriaco, cas d’étude central de ce travail. Cette opération amène la question de la modernisation des produits de l’extractivisme et de la capacité des populations rurales à s’insérer dans les circuits commerciaux. La transformation de la noix de babaçu [Orbignya spp.], activité en désuétude, exprime pourtant une identité collective forte, qui s’incarne dans un mouvement social emblématique des transformations du milieu politico-associatif rural, qui entre dans une démarche réflexive et acquiert plus d’autonomie, concourant à structurer les communautés rurales en zone de front pionnier. Cette dynamique régionale se complète par les problématiques actuelles du secteur sidérurgique, activité pionnière de fort impact, mais dont l’implantation dans les années quatre-vingts a donné une envergure nationale à la région d’Imperatriz. Aujourd’hui, pour assurer la « durabilité » de ses activités, le secteur est contraint de déployer un véritable système spatial articulé autour d’une forêt plantée d’eucalyptus, de sa transformation en charbon végétal aboutissant aux lingots de fer-gueuse. / This study presents the spatial and temporal components that have led to the organization of a post pioneer front located in the oriental part of the Brazilian Amazon region [pre-Amazônia maranhense, Imperatriz]. In order to understand the settlement process of this region, we first outline a cartographic analysis of the life event and migratory movements of the first generation, who had come to the region massively in the 1960ies; second, we compare the latter with the actual circulation strategies of the younger generations. The evolution of land tenure, which is inherent to the consolidation of a settlement front, has taken place continuously by a series of direct interventions by the Federal Government, first privileging individual regularization in order to restore social peace [Getat]; then collective land use aiming at the preservation of the environment [protected areas]. In this work, we reconstruct the different steps of the land property regulation chain, in order to identify the conditions under which small farmers could become “property owners” and to show how this process ultimately led to the delimitation of the Ciriaco extractive reserve, which constitutes our main case study, . This operation leads to the question of the modernization of the extractive economy and to the capacity of rural populations to take over in trading and to develop economic circuits. If the transformation of the babassu nut [Orbignya spp.] seems to be bound to become extinct, the activity however still holds a strong collective identity, embodied in a social movement which has been emblematic of the transformations of rural politico-associative entities. They are adopting a more reflexive position, and gaining more autonomy, contributing to structure the different rural communities of the settlement front. This regional dynamics must be completed by current issues of the pig-iron sector, a pioneer activity which had a heavy impact on the region around Imperatriz but has also contributed to give it an [inter]national importance since the 1980ies. Today, in order to ensure the sustainability of its activities, the pig-iron sector is compelled to spread out a real spatial system articulated around a forest of planted eucalyptus and its transformation into charcoal and then pig-iron ingot.
315

Povýběrová Inference: Lasso & Skupinové Lasso / Post-selection Inference: Lasso & Group Lasso

Bouř, Vojtěch January 2017 (has links)
The lasso is a popular tool that can be used for variable selection and esti- mation, however, classical statistical inference cannot be applied for its estimates. In this thesis the classical and the group lasso is described together with effici- ent algorithms for the solution. The key part is dedicated to the post-selection inference for the lasso estimates where we explain why the classical inference is not suitable. Three post-selection tests for the lasso are described and one test is proposed also for the group lasso. The tests are compared in simulations where finite sample properties are examined. The tests are further applied on a practical example. 1
316

Využití adverzálních příkladů pro zpracování přirozeného jazyka / Using Adversarial Examples in Natural Language Processing

Bělohlávek, Petr January 2017 (has links)
Machine learning has been paid a lot of attention in recent years. One of the studied fields is employment of adversarial examples. These are artifi- cially constructed examples which evince two main features. They resemble the real training data and they deceive already trained model. The ad- versarial examples have been comprehensively investigated in the context of deep convolutional neural networks which process images. Nevertheless, their properties have been rarely examined in connection with NLP-processing networks. This thesis evaluates the effect of using the adversarial examples during the training of the recurrent neural networks. More specifically, the main focus is put on the recurrent networks whose text input is in the form of a sequence of word/character embeddings, which have not been pretrained in advance. The effects of the adversarial training are studied by evaluating multiple NLP datasets with various characteristics.
317

Adaptive Kernel Functions and Optimization Over a Space of Rank-One Decompositions

Wang, Roy Chih Chung January 2017 (has links)
The representer theorem from the reproducing kernel Hilbert space theory is the origin of many kernel-based machine learning and signal modelling techniques that are popular today. Most kernel functions used in practical applications behave in a homogeneous manner across the domain of the signal of interest, and they are called stationary kernels. One open problem in the literature is the specification of a non-stationary kernel that is computationally tractable. Some recent works solve large-scale optimization problems to obtain such kernels, and they often suffer from non-identifiability issues in their optimization problem formulation. Many practical problems can benefit from using application-specific prior knowledge on the signal of interest. For example, if one can adequately encode the prior assumption that edge contours are smooth, one does not need to learn a finite-dimensional dictionary from a database of sampled image patches that each contains a circular object in order to up-convert images that contain circular edges. In the first portion of this thesis, we present a novel method for constructing non-stationary kernels that incorporates prior knowledge. A theorem is presented that ensures the result of this construction yields a symmetric and positive-definite kernel function. This construction does not require one to solve any non-identifiable optimization problems. It does require one to manually design some portions of the kernel while deferring the specification of the remaining portions to when an observation of the signal is available. In this sense, the resultant kernel is adaptive to the data observed. We give two examples of this construction technique via the grayscale image up-conversion task where we chose to incorporate the prior assumption that edge contours are smooth. Both examples use a novel local analysis algorithm that summarizes the p-most dominant directions for a given grayscale image patch. The non-stationary properties of these two types of kernels are empirically demonstrated on the Kodak image database that is popular within the image processing research community. Tensors and tensor decomposition methods are gaining popularity in the signal processing and machine learning literature, and most of the recently proposed tensor decomposition methods are based on the tensor power and alternating least-squares algorithms, which were both originally devised over a decade ago. The algebraic approach for the canonical polyadic (CP) symmetric tensor decomposition problem is an exception. This approach exploits the bijective relationship between symmetric tensors and homogeneous polynomials. The solution of a CP symmetric tensor decomposition problem is a set of p rank-one tensors, where p is fixed. In this thesis, we refer to such a set of tensors as a rank-one decomposition with cardinality p. Existing works show that the CP symmetric tensor decomposition problem is non-unique in the general case, so there is no bijective mapping between a rank-one decomposition and a symmetric tensor. However, a proposition in this thesis shows that a particular space of rank-one decompositions, SE, is isomorphic to a space of moment matrices that are called quasi-Hankel matrices in the literature. Optimization over Riemannian manifolds is an area of optimization literature that is also gaining popularity within the signal processing and machine learning community. Under some settings, one can formulate optimization problems over differentiable manifolds where each point is an equivalence class. Such manifolds are called quotient manifolds. This type of formulation can reduce or eliminate some of the sources of non-identifiability issues for certain optimization problems. An example is the learning of a basis for a subspace by formulating the solution space as a type of quotient manifold called the Grassmann manifold, while the conventional formulation is to optimize over a space of full column rank matrices. The second portion of this thesis is about the development of a general-purpose numerical optimization framework over SE. A general-purpose numerical optimizer can solve different approximations or regularized versions of the CP decomposition problem, and they can be applied to tensor-related applications that do not use a tensor decomposition formulation. The proposed optimizer uses many concepts from the Riemannian optimization literature. We present a novel formulation of SE as an embedded differentiable submanifold of the space of real-valued matrices with full column rank, and as a quotient manifold. Riemannian manifold structures and tangent space projectors are derived as well. The CP symmetric tensor decomposition problem is used to empirically demonstrate that the proposed scheme is indeed a numerical optimization framework over SE. Future investigations will concentrate on extending the proposed optimization framework to handle decompositions that correspond to non-symmetric tensors.
318

Méthodes de démélange non-linéaires pour l'imagerie hyperspectrale / Non-linear unmixing methods for hyperspectral imaging

Nguyen Hoang, Nguyen 03 December 2013 (has links)
Dans cette thèse, nous avons présenté les aspects de la technologie d'imagerie hyperspectrale en concentrant sur le problème de démélange non-linéaire. Pour cette tâche, nous avons proposé trois solutions. La première consiste à intégrer les avantages de l'apprentissage de variétés dans les méthodes de démélange classique pour concevoir leurs versions non-linéaires. Les résultats avec les données générées sur une variété bien connue - le "Swissroll"- donne des résultats prometteurs. Les méthodes fonctionnent beaucoup mieux avec l'augmentation de la non-linéarité. Cependant, l'absence de contrainte de non-négativité dans ces méthodes reste une question ouverte pour des améliorations à trouver. La deuxième proposition vise à utiliser la méthode de pré-image pour estimer une transformation inverse de l'espace de données entrées des pixels vers l'espace des abondances. L'ajout des informations spatiales sous forme "variation totale" est également introduit pour rendre l'algorithme plus robuste au bruit. Néanmoins, le problème d'obtention des données de réalité terrain nécessaires pour l'étape d'apprentissage limite l'application de ce type d'algorithmes. / In this thesis , we present several aspects of hyperspectral imaging technology , while focusing on the problem of non- linear unmixing . We have proposed three solutions for this task. The first one is integrating the advantages of manifold learning in classical unmixing methods to design their nonlinear versions . Results with data generated on a well-known manifold- the " Swissroll " - seem promising. The methods work much better with the increase in non- linearity compared with their linear version. However, the absence of constraint of non- negativity in these methods remains an open question for improvements . The second proposal is using the pre-image method for estimating an inverse transformation of the data form pixel space to abundance of space . The adoption of spatial information as " total variation " is also introduced to make the algorithm more robust to noise . However, the problem of obtaining ground truth data required for learning step limits the application of such algorithms.
319

Ekonomie vychýleného odhadu / Economics of Biased Estimation

Drvoštěp, Tomáš January 2014 (has links)
This thesis investigates optimality of heuristic forecasting. According to Goldstein a Gigerenzer (2009), heuristics can be viewed as predictive models, whose simplicity is exploiting the bias-variance trade-off. Economic agents learning in the context of rational expectations (Marcet a Sargent 1989) employ, on the contrary, complex models of the whole economy. Both of these approaches can be perceived as an optimal response complexity of the prediction task and availability of observations. This work introduces a straightforward extension to the standard model of decision making under uncertainty, where agents utility depends on accuracy of their predictions and where model complexity is moderated by regularization parameter. Results of Monte Carlo simulations reveal that in complicated environments, where few observations are at disposal, it is beneficial to construct simple models resembling heuristics. Unbiased models are preferred in more convenient conditions.
320

Data Science and the Ice-Cream Vendor Problem

Azasoo, Makafui 01 August 2021 (has links)
Newsvendor problems in Operations Research predict the optimal inventory levels necessary to meet uncertain demands. This thesis examines an extended version of a single period multi-product newsvendor problem known as the ice cream vendor problem. In the ice cream vendor problem, there are two products – ice cream and hot chocolate – which may be substituted for one another if the outside temperature is no too hot or not too cold. In particular, the ice cream vendor problem is a data-driven extension of the conventional newsvendor problem which does not require the assumption of a specific demand distribution, thus allowing the demand for ice cream and hot chocolate respectively to be temperature dependent. Using Discrete Event Simulation, we first simulate a real-world scenario of an ice cream vendor problem via a demand whose expected value is a function of temperature. A sample average approximation technique is subsequently used to transform the stochastic newsvendor program into a feature-driven linear program based on the exogenous factors of probability of rainfall and temperature. The resulting problem is a multi-product newsvendor linear program with L1-regularization. The solution to this problem yields the expected cost to the ice cream vendor as well as the optimal order quantities for ice cream and hot chocolate, respectively.

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