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There is a growing need to assist radiologists in performing X-ray readings and diagnoses fast, comfortably, and effectively. As radiologists strive to maximize productivity, it is essential to consider the impact of reading rooms in interpreting complex examinations and ensure that higher volume and reporting speeds do not compromise patient outcomes. Virtual Reality (VR) is a disruptive technology for clinical practice in assessing X-ray images. We argue that conjugating eye-tracking with VR devices and Machine Learning may overcome obstacles posed by inadequate ergonomic postures and poor room conditions that often cause erroneous diagnostics when professionals examine digital images.

Gaussian mixture models (GMMs) are fundamental tools in statistical and data sciences. We study the moments of multivariate Gaussians and GMMs. The $d$-th moment of an $n$-dimensional random variable is a symmetric $d$-way tensor of size $n^d$, so working with moments naively is assumed to be prohibitively expensive for $d>2$ and larger values of $n$. In this work, we develop theory and numerical methods for \emph{implicit computations} with moment tensors of GMMs, reducing the computational and storage costs to $\mathcal{O}(n^2)$ and $\mathcal{O}(n^3)$, respectively, for general covariance matrices, and to $\mathcal{O}(n)$ and $\mathcal{O}(n)$, respectively, for diagonal ones. We derive concise analytic expressions for the moments in terms of symmetrized tensor products, relying on the correspondence between symmetric tensors and homogeneous polynomials, and combinatorial identities involving Bell polynomials. The primary application of this theory is to estimating GMM parameters (means and covariances) from a set of observations, when formulated as a moment-matching optimization problem. If there is a known and common covariance matrix, we also show it is possible to debias the data observations, in which case the problem of estimating the unknown means reduces to symmetric CP tensor decomposition. Numerical results validate and illustrate the numerical efficiency of our approaches. This work potentially opens the door to the competitiveness of the method of moments as compared to expectation maximization methods for parameter estimation of GMMs.

This work presents the integration of the IEEE 802.21 framework with the Entity Title Architecture (ETArch), a clean slate approach that is deployed atop OpenFlow. In the resultant architecture, network mobility is provided within the Workspace, a logical channel able to gather multiple communicating participants. This paper describes the main architecture components and the signaling approach deployed in a handover scenario by providing the details of the integration between 802.21, OpenFlow, and Entity Title Control protocols.

One of the most common pitfalls often found in high dimensional biological data sets are correlations between the features. This may lead to statistical and machine learning methodologies overvaluing or undervaluing these correlated predictors, while the truly relevant ones are ignored. In this paper, we will define a new method called \textit{pairwise permutation algorithm} (PPA) with the aim of mitigating the correlation bias in feature importance values. Firstly, we provide a theoretical foundation, which builds upon previous work on permutation importance. PPA is then applied to a toy data set, where we demonstrate its ability to correct the correlation effect. We further test PPA on a microbiome shotgun dataset, to show that the PPA is already able to obtain biological relevant biomarkers., Submitted and accepted by AIMLAI, ECML PKDD 2021: European Conference on Machine Learning and Principles and Practice of Knowledge Discovery in Databases

The development of ORC based micro-CHP systems to retrofit the current combi-boilers is receiving noticeable attention from research centres and companies due to the huge dimension of the potential market. Recognizing the importance that the evaporator has on the technological/ commercial success of these systems, and instead of avoiding the problem through the adoption of alternative restricting solutions (i.e. indirect vaporization process), it seems reasonable to face the challenges associated with the development of a specifically designed ORC-evaporator capable to directly use the hightemperature combustion gases to perform the vaporization of the working fluid (direct vaporization). In an attempt to overcome those challenges and fulfil this technological gap, that is believed to be preventing the widespread use of these systems, this paper presents and discuss some of its main design principles. From those principles emerged a hybrid topping/bottoming) CHP configuration in which the thermal energy is produced stepwise: firstly in the ORC-condenser and then in a post-heater, that is integrated on the ORC-evaporator, directly with the combustion gases. A model of this configuration was developed to determine the fraction of the CHP water heating process performed in the post-heater that maximizes the primary energy savings (in more than 20%) and ORC net power output (in more than 5%) for a wide range of CHP operating conditions. When compared to a standard CHP configuration, this solution show benefits for the greater part of those conditions. Besides solving the safety issue posed by the ORC-evaporator requirements and the performance benefits shown, this configuration has an additional positive side effect: the decrease of the combustion gases��� temperature before they reach the organic fluid heat-exchanger section in the ORC-evaporator that leads to a reduction of the risk of the working fluid thermal degradation.

Os Tumores do Estroma Gastro-Intestinal (GIST) s��o tumores raros do tracto gastro-intestinal. Menos de 5% destes n��o est��o associados ao tracto gastro-intestinal, sendo definidos por EGISTs. Os EGISTs do mesoc��lon s��o extremamente raros, com apenas alguns casos descritos na literatura. Apresentamos o caso de uma doente de 82 anos com quadro de n��useas e v��mitos com 1 m��s de evolu����o, tendo realizado ecografia e TC que mostrou ���observa-se uma volumosa forma����o tumoral, em grande parte qu��stica, com significativa toma de contraste nas ��reas s��lidas, que mede cerca de 16,8x11,2 cm. Esta forma����o �� aparentemente independente da cauda do p��ncreas, estando na prov��vel depend��ncia da parede g��strica...���, realizou eco-endoscopia com PAAF que foi inconclusiva. Foi submetida a laparotomia exploradora com gastrectomia at��pica e excis��o parcial do folheto anterior do mesoc��lon transverso e omentectomia em bloco com o tumor. A anatomia patol��gica revelou ���Tumor do estroma extragastrointestinal maligno, do tipo epitelioide. pT4N0���. Por vontade da doente n��o foi realizada terap��utica adjuvante. Apesar de raros, os GISTs s��o os tumores mesenquimatosos mais comuns do tracto gastro-intestinal, no entanto EGISTs do mesoc��lon s��o extremamente raros. Contrariamente ao que acontece nos GISTs, a patog��nese, incid��ncia e progn��stico n��o est��o completamente estabelecidos para os EGISTs uma vez que poucos casos est��o descritos. Apresentamos uma breve revis��o sobre o diagn��stico e abordagem terap��utica nestes casos., Revista Portuguesa de Cirurgia, n. 50 (2021): N��mero 50 - Mar��o 2021

Submitted by Jo??o Pereira (joao_jou@hotmail.com) on 2022-02-09T15:16:20Z No. of bitstreams: 4 Tese Jo??o Filipe Bezerra Pereira-PPGMAT.pdf: 769250 bytes, checksum: 190f20a2da0c70c9402aa25eeb82f7da (MD5) cartaencaminhamento.pdf: 272887 bytes, checksum: 853c53e79b5dfde8ce35c30d7792a037 (MD5) SEI_UFAM - 0539380 - Ata Defesa Filipe.pdf: 101404 bytes, checksum: c5ad526b0045839d1ea989ae3a9d8ed9 (MD5) SEI_UFAM - 0804068 - Ata.pdf: 88962 bytes, checksum: 93a40d812201fbd4c770d9a27bd04f96 (MD5) Approved for entry into archive by P??s Gradua????o Matem??tica (pos-matematica@ufam.edu.br) on 2022-02-09T17:38:29Z (GMT) No. of bitstreams: 4 Tese Jo??o Filipe Bezerra Pereira-PPGMAT.pdf: 769250 bytes, checksum: 190f20a2da0c70c9402aa25eeb82f7da (MD5) cartaencaminhamento.pdf: 272887 bytes, checksum: 853c53e79b5dfde8ce35c30d7792a037 (MD5) SEI_UFAM - 0539380 - Ata Defesa Filipe.pdf: 101404 bytes, checksum: c5ad526b0045839d1ea989ae3a9d8ed9 (MD5) SEI_UFAM - 0804068 - Ata.pdf: 88962 bytes, checksum: 93a40d812201fbd4c770d9a27bd04f96 (MD5) Approved for entry into archive by Divis??o de Documenta????o/BC Biblioteca Central (ddbc@ufam.edu.br) on 2022-02-09T21:06:38Z (GMT) No. of bitstreams: 4 Tese Jo??o Filipe Bezerra Pereira-PPGMAT.pdf: 769250 bytes, checksum: 190f20a2da0c70c9402aa25eeb82f7da (MD5) cartaencaminhamento.pdf: 272887 bytes, checksum: 853c53e79b5dfde8ce35c30d7792a037 (MD5) SEI_UFAM - 0539380 - Ata Defesa Filipe.pdf: 101404 bytes, checksum: c5ad526b0045839d1ea989ae3a9d8ed9 (MD5) SEI_UFAM - 0804068 - Ata.pdf: 88962 bytes, checksum: 93a40d812201fbd4c770d9a27bd04f96 (MD5) Made available in DSpace on 2022-02-09T21:06:38Z (GMT). No. of bitstreams: 4 Tese Jo??o Filipe Bezerra Pereira-PPGMAT.pdf: 769250 bytes, checksum: 190f20a2da0c70c9402aa25eeb82f7da (MD5) cartaencaminhamento.pdf: 272887 bytes, checksum: 853c53e79b5dfde8ce35c30d7792a037 (MD5) SEI_UFAM - 0539380 - Ata Defesa Filipe.pdf: 101404 bytes, checksum: c5ad526b0045839d1ea989ae3a9d8ed9 (MD5) SEI_UFAM - 0804068 - Ata.pdf: 88962 bytes, checksum: 93a40d812201fbd4c770d9a27bd04f96 (MD5) Previous issue date: 2021-05-14 FAPEAM - Funda????o de Amparo ?? Pesquisa do Estado do Amazonas In this thesis we will consider Riemannian manifolds isometrically immersed in semiRiemannian manifolds with constant sectional curvature. By establishing a connection between concircular fields and conformal fields, as well as by assuming that our Riemannian manifolds are totally umbilical, we will determine a Ricci almost soliton structure on them. In addition, we will study a manifestation of the Tashiro???s Theorem in this context by means of which we will construct three new examples of gradient Ricci almost solitons. Nesta tese vamos considerar variedades Riemannianas imersas isometricamente em uma variedade semi-Riemanniana de curvatura seccional constante. Estabelecendo uma conex??o entre campos concirculares e campos conformes, bem como supondo que nossas variedades Riemannianas s??o totalmente umb??licas, vamos determinar uma estrutura de quase s??liton de Ricci nelas. Al??m disso, vamos apresentar uma manifesta????o do Teorema de Tashiro neste contexto e assim vamos construir v??rios exemplos concretos.

ln the context of project Ci��ncia Viva da Mina do Lousa/, it was decided to construct an immersive virtual reality environment in which a group ofpeople, for example students, can do a virtual visit to a mine. This artic/e discusses and rationalizes the diverse techno/ogical choices made to achieve this task., 15�� Encontro Portugu��s de Computa����o Gr��fica, Realidade Aumentada e Vis��o por Computador, 69, 77, Vasco Costa, Jo��o Madeiras Pereira, and Miguel Dias, Distributed/Network Graphics, Graphics Packages, Virtual Reality

Esta comunica����o apresenta uma plataforma para a gest��o de aplica����es multimodais de forma reutiliz��vel e extens��vel. Para atingir este objectivo focamos a arquitectura nas Capacidades dos dispositivos e nas Inten����es dos utilizadores. Abordamos, em particular, ambientes colaborativos onde a integra����o de v��rias modalidades e aplica����es obriga �� exist��ncia de um sistema extens��vel que combine, em tempo real, diversos componentes provenientes de plataformas heterog��neas. Este artigo descreve o enquadramento proposto e demonstra como interligar aplica����es e utilizadores em torno de um ambiente imersivo (tiled display wall), incluindo diferentes modalidades de interac����o n��o convencionais e aplica����es., Interac����o 2006 - 2�� Confer��ncia Nacional em Interac����o Pessoa-M��quina, Posters e Demos, 233, 236, Tiago Guerreiro, Vitor Fernandes, Bruno Ara��jo, Joaquim Jorge, and Jo��o Pereira, Framework, Interfaces Multimodais, Extensibilidade, Reutiliza����o, Capacidades, Inten����es, Colabora����o

Um jogo de computador 3D, que tem como finalidade permitir que jogadores portadores de paralisia cerebral possam jogar o jogo de Boccia, foi desenvolvido ao abrigo de uma tese de mestrado no Instituto Superior T��cnico. Na sequ��ncia deste trabalho, foi efectuado um estudo de avalia����o e adequa����o do referido jogo aos jogadores da equipa de Boccia do Centro de Paralisia Cerebral de Beja. Para tal, foram utilizados v��rios m��todos, em diferentes fases, e que passaram por uma avalia����o efectuada por peritos em interfaces e de jogo real, por testes de utiliza����o dos utentes, com base em registos de observa����es em papel e em v��deo e, finalmente, pela aplica����o de um inqu��rito sob a forma de entrevista aos jogadores. A experi��ncia obtida poder��, depois, ser aplicada na adequa����o e avalia����o de outros sistemas de software (tecnologias de apoio) a este tipo de utilizadores que apresentam necessidades especiais e que devem tamb��m ter respostas adequadas por parte destes sistemas., Interac����o 2006 - 2�� Confer��ncia Nacional em Interac����o Pessoa-M��quina, Sess��es T��cnicas, 27, 34, Lu��s Carlos Bruno, Jo��o Brisson Lopes, Lu��s Filipe Garcia, and Jo��o Madeiras Pereira, M��todos de Avalia����o de Interfaces, Pessoas com Necessidades Especiais, Acessibilidade, Desenho Centrado no Utilizador

Change is constant in the modern world. What is new today, tomorrow is already outdated. This happens due to technological development, the intense flow of information, the globalization process, the deeper knowledge that drives people to want to quickly change the artifacts that support their daily lives. In this way, the modern lifestyle is characterized by constant changes, faster, more immediate results, information in large quantities, more clarification, stimulated creativity and practicality. This is good, but it also has its disadvantages. One of them is the difficulty in following all these changes and adjusting to the new style while respecting a low budget and remaining faithful to ecological principles. Thus, the times indicate a greater predisposition to adhere to modular furniture as it seems to be the perfect solution in terms of adaptation and mobility. After interpreting the basic needs of young teen users, and combining design with technology, this project aimed to develop several functional, innovative and eco efficient alternative furniture solutions. Designing a single wooden module or wooden composites that allows the construction of several pieces of furniture, in order to equip a room for a young teenager, was the problem worked on. 101E-1BBD-F278 | Jo?o Carlos Monteiro Martins info:eu-repo/semantics/publishedVersion

Introdu??o: o transtorno por uso de coca?na (TUC) ? uma doen?a grave e que apresenta consequ?ncias piores entre as mulheres. Sabe-se que sintomas de abstin?ncia ? coca?na, como craving e depress?o, impactam negativamente no curso da doen?a. Nesse sentido, a Ocitocina (OC) tem demonstrado efeito ben?fico sobre os sintomas de abstin?ncia ? coca?na em estudos com animais, sendo empregada com seguran?a em humanos para outras patologias. Objetivos: avaliar o efeito da OC intranasal sobre sintomas de abstin?ncia ? coca?na em mulheres portadoras de TUC, atrav?s de um ensaio cl?nico duplo-cego randomizado placebo-controlado. M?todos: 83 mulheres em desintoxica??o hospitalar foram randomicamente alocadas a tr?s condi??es experimentais: tratamento convencional com administra??o de OC intranasal 24UI 12/12horas (grupo OCT), tratamento convencional com administra??o de solu??o placebo 12/12 horas (grupo PBO) e tratamento convencional isolado (grupo CON). As participantes passaram por uma avalia??o diagn?stica (SCID 5), de intelig?ncia (WASI) e da gravidade da depend?ncia qu?mica (ASI-6). A interven??o espec?fica para os grupos OCT e PBO foi executada do oitavo ao 17? dia de interna??o. Os sintomas de abstin?ncia (CSSA) e depressivos (QIDS-SR) foram avaliados antes (T1), durante (T2) e ap?s (T3) a interven??o. Resultados: a OC intranasal reduziu os efeitos da abstin?ncia ? coca?na durante a interna??o, com diminui??o dos sintomas de apetite e depressivos. Os resultados espec?ficos para depress?o (QIDS-SR) corroboraram esses achados. As mulheres do grupo PBO tamb?m tiveram redu??o dos sintomas depressivos, mas apresentaram menor redu??o destes quando comparadas ao grupo OCT no decorrer da interna??o. Conclus?es: os resultados apoiam as evid?ncias de efeitos positivos da OC sobre a abstin?ncia ? coca?na em estudos com modelo animal, e contribuem com a hip?tese de melhora da abstin?ncia atrav?s de circuitos neuronais envolvidos com a regula??o do humor, al?m do sistema de recompensa. Introduction: the cocaine use disorder (CUD) is a severe disease, especially among women, who develop more serious consequences of the addiction. Cocaine withdrawal components, such as craving and depressive symptoms, may impact negatively the course of the disease. The neuropeptide Oxytocin (OC) has shown positive effects on cocaine withdrawal symptoms through animal studies, and has been used in humans with safety in the treatment of other medical conditions. Objectives: to evaluate the effect of intranasal OC on cocaine withdrawal symptoms of women with CUD, using a randomized double-blind placebo-controlled trial. Methods: 83 female inpatients with CUD were randomly allocated to 3 experimental conditions: conventional treatment plus intranasal OC administration twice daily (OCT), conventional treatment plus intranasal placebo solution administration twice daily (PBO) and conventional treatment only (CON). The participants underwent a diagnostic interview (SCID 5), evaluation of the severity of the addiction (ASI-6) and intelligence (WASI). The OC or placebo intervention comprised the period between days 8 and 17 from admission. The withdrawal (CSSA) and depressive (QIDS-SR) symptoms were assessed before (T1), during (T2) and after (T3) the intervention. Results: intranasal OC reduced withdrawal symptoms compared to placebo and conventional treatment. This effect was mediated by an improvement on appetite and mood symptoms. Analysis of the instrument specific for depression (QIDS-SR) showed similar results. Both OCT and PBO groups improved depressive symptoms, but women under OCT condition showed greater improvement on the course of detoxification. Conclusion: these results support previous animal studies evidences of positive effects of OC on cocaine withdrawal, adding to the hypothesis that OC exerts its effects on withdrawal symptoms through mood regulation circuits and reward system interactions. Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES

We introduce the Subspace Power Method (SPM) for calculating the CP decomposition of low-rank even-order real symmetric tensors. This algorithm applies the tensor power method of Kolda-Mayo to a certain modified tensor, constructed from a matrix flattening of the original tensor, and then uses deflation steps. Numerical simulations indicate SPM is roughly one order of magnitude faster than state-of-the-art algorithms, while performing robustly for low-rank tensors subjected to additive noise. We obtain rigorous guarantees for SPM regarding convergence and global optima, for tensors of rank up to roughly the square root of the number of tensor entries, by drawing on results from classical algebraic geometry and dynamical systems. In a second contribution, we extend SPM to compute De Lathauwer's symmetric block term tensor decompositions. As an application of the latter decomposition, we provide a method-of-moments for generalized principal component analysis., 58 pages, 7 figures, 2 tables. v3: merged introduction and literature review; clarified convergence proof; increased the number of trials in the numerical experiments; and other improvements

We propose the Graph Space Embedding (GSE), a technique that maps the input into a space where interactions are implicitly encoded, with little computations required. We provide theoretical results on an optimal regime for the GSE, namely a feasibility region for its parameters, and demonstrate the experimental relevance of our findings. Next, we introduce a strategy to gain insight on which interactions are responsible for the certain predictions, paving the way for a far more transparent model. In an empirical evaluation on a real-world clinical cohort containing patients with suspected coronary artery disease, the GSE achieves far better performance than traditional algorithms., 7 pages

With the rise of Social Media, people obtain and share information almost instantly on a 24/7 basis. Many research areas have tried to gain valuable insights from these large volumes of freely available user generated content. With the goal of extracting knowledge from social media streams that might be useful in the context of intelligent transportation systems and smart cities, we designed and developed a framework that provides functionalities for parallel collection of geo-located tweets from multiple pre-defined bounding boxes (cities or regions), including filtering of non-complying tweets, text pre-processing for Portuguese and English language, topic modeling, and transportation-specific text classifiers, as well as, aggregation and data visualization. We performed an exploratory data analysis of geo-located tweets in 5 different cities: Rio de Janeiro, S\~ao Paulo, New York City, London and Melbourne, comprising a total of more than 43 million tweets in a period of 3 months. Furthermore, we performed a large scale topic modelling comparison between Rio de Janeiro and S\~ao Paulo. Interestingly, most of the topics are shared between both cities which despite being in the same country are considered very different regarding population, economy and lifestyle. We take advantage of recent developments in word embeddings and train such representations from the collections of geo-located tweets. We then use a combination of bag-of-embeddings and traditional bag-of-words to train travel-related classifiers in both Portuguese and English to filter travel-related content from non-related. We created specific gold-standard data to perform empirical evaluation of the resulting classifiers. Results are in line with research work in other application areas by showing the robustness of using word embeddings to learn word similarities that bag-of-words is not able to capture.

In the last years researchers in the field of intelligent transportation systems have made several efforts to extract valuable information from social media streams. However, collecting domain-specific data from any social media is a challenging task demanding appropriate and robust classification methods. In this work we focus on exploring geo-located tweets in order to create a travel-related tweet classifier using a combination of bag-of-words and word embeddings. The resulting classification makes possible the identification of interesting spatio-temporal relations in S\~ao Paulo and Rio de Janeiro.

We investigate an inverse problem in time-frequency localization: the approximation of the symbol of a time-frequency localization operator from partial spectral information by the method of accumulated spectrograms (the sum of the spectrograms corresponding to large eigenvalues). We derive a sharp bound for the rate of convergence of the accumulated spectrogram, improving on recent results., 14 pages, 2 figures

Submitted by Jo??o Pereira (joao_jou@hotmail.com) on 2018-09-10T15:36:42Z No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Disserta????o Vers??o Final Jo??o Filipe com capa (3).pdf: 9622644 bytes, checksum: 8e5d2a24add110a015378d665087c184 (MD5) Approved for entry into archive by PPG Matem??tica (ppgmufam@gmail.com) on 2018-09-10T15:39:34Z (GMT) No. of bitstreams: 2 license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Disserta????o Vers??o Final Jo??o Filipe com capa (3).pdf: 9622644 bytes, checksum: 8e5d2a24add110a015378d665087c184 (MD5) Rejected by Divis??o de Documenta????o/BC Biblioteca Central (ddbc@ufam.edu.br), reason: A Carta de Encaminhamento para Autodep??sito precisa ser depositada. Siga as instru????es http://biblioteca.ufam.edu.br/servicos/teses-e-dissertacoes on 2018-09-10T18:01:09Z (GMT) Submitted by Jo??o Pereira (joao_jou@hotmail.com) on 2018-09-10T19:51:06Z No. of bitstreams: 3 Disserta????o Vers??o Final Jo??o Filipe com capa (3).pdf: 9622644 bytes, checksum: 8e5d2a24add110a015378d665087c184 (MD5) Carta de Encaminhamento - Jo??o Filipe (1).pdf: 345703 bytes, checksum: 0b5e944c4f490db26b7032a876662635 (MD5) Ata de Defesa - Jo??o Felipe.pdf: 448121 bytes, checksum: c6b961e6c79bdc34c86617f4f4e12aaa (MD5) Approved for entry into archive by PPG Matem??tica (ppgmufam@gmail.com) on 2018-09-11T12:52:07Z (GMT) No. of bitstreams: 3 Disserta????o Vers??o Final Jo??o Filipe com capa (3).pdf: 9622644 bytes, checksum: 8e5d2a24add110a015378d665087c184 (MD5) Carta de Encaminhamento - Jo??o Filipe (1).pdf: 345703 bytes, checksum: 0b5e944c4f490db26b7032a876662635 (MD5) Ata de Defesa - Jo??o Felipe.pdf: 448121 bytes, checksum: c6b961e6c79bdc34c86617f4f4e12aaa (MD5) Approved for entry into archive by Divis??o de Documenta????o/BC Biblioteca Central (ddbc@ufam.edu.br) on 2018-09-11T14:51:20Z (GMT) No. of bitstreams: 3 Disserta????o Vers??o Final Jo??o Filipe com capa (3).pdf: 9622644 bytes, checksum: 8e5d2a24add110a015378d665087c184 (MD5) Carta de Encaminhamento - Jo??o Filipe (1).pdf: 345703 bytes, checksum: 0b5e944c4f490db26b7032a876662635 (MD5) Ata de Defesa - Jo??o Felipe.pdf: 448121 bytes, checksum: c6b961e6c79bdc34c86617f4f4e12aaa (MD5) Made available in DSpace on 2018-09-11T14:51:20Z (GMT). No. of bitstreams: 3 Disserta????o Vers??o Final Jo??o Filipe com capa (3).pdf: 9622644 bytes, checksum: 8e5d2a24add110a015378d665087c184 (MD5) Carta de Encaminhamento - Jo??o Filipe (1).pdf: 345703 bytes, checksum: 0b5e944c4f490db26b7032a876662635 (MD5) Ata de Defesa - Jo??o Felipe.pdf: 448121 bytes, checksum: c6b961e6c79bdc34c86617f4f4e12aaa (MD5) Previous issue date: 2015-03-06 CAPES - Coordena????o de Aperfei??oamento de Pessoal de N??vel Superior Compact flat surfaces of homogeneous Riemannian 3-manifolds with isometry group of dimension 4 are classified. Nonexistence results for compact constant Gauss curvature surfaces in these 3-manifolds are established. Neste trabalho vamos classificar as superf??cies compactas planas em variedades riemannianas homog??neas tridimensionais com grupo de isometrias de dimens??o 4. Al??m disso, vamos estabelecer resultados de inexist??ncia de superf??cies compactas de curvatura gaussiana constante nestas variedades.

Let $D_{T}$ and $B_{��}$ denote the operators which cut the time content outside $T$ and the frequency content outside $��$, respectively. The prolate spheroidal functions are the eigenfunctions of the operator $P_{T,��}=D_{T}B_{��}D_{T}$. With the aim of formulating in precise mathematical terms the notion of Nyquist rate, Landau and Pollack have shown that, asymptotically, the number of such functions with eigenvalue close to one is $\approx \frac{\left\vert T\right\vert \left\vert ��\right\vert }{2��}$. We have recently revisited this problem with a new approach: instead of counting the number of eigenfunctions with eigenvalue close to one, we count the maximum number of orthogonal $��$-pseudoeigenfunctions with $��$-pseudoeigenvalue one. Precisely, we count how many orthogonal functions have a maximum of energy $��$ outside the domain $T\times ��$, in the sense that $\left\Vert P_{T,��}f-f\right\Vert ^{2}\leq ��$. We have recently discovered that the sharp asymptotic number is $\approx (1-��)^{-1}\frac{\left\vert T\right\vert \left\vert ��\right\vert }{2��}$. The proof involves an explicit construction of the pseudoeigenfunctions of $P_{T,��}$. When $T$ and $��$ are intervals we call them pseudo prolate spheroidal functions. In this paper we explain how they are constructed., 5 pages, Accepted in SampTA

We obtain a refinement of the degrees of freedom estimate of Landau and Pollak. More precisely, we estimate, in terms of $��$, the increase in the degrees of freedom resulting upon allowing the functions to contain a certain prescribed amount of energy $��$ outside a region delimited by a set $T$ in time and a set $��$ in frequency. In this situation, the lower asymptotic Nyquist density $\vert T\vert \vert ��\vert /2��$ is increased to $(1+��)\vert T\vert \vert ��\vert /2��$. At the technical level, we prove a pseudospectra version of the classical spectral dimension result of Landau and Pollak, in the multivariate setting of Landau. Analogous results are obtained for Gabor localization operators in a compact region of the time-frequency plane., 13 pages, no figures

Made available in DSpace on 2016-04-28T14:58:35Z (GMT). No. of bitstreams: 1 2006 - Jo?o Batista Alves Pereira.pdf: 1832144 bytes, checksum: 36798c7d302cc3a5d500e230c9f5af03 (MD5) Previous issue date: 2006-02-21 Evaluation of the vegetal growth, hydric necessity and water use efficiency by bell pepper crop (Capsicum annum. L.) under organic management in system of seeding with prepare soil and no till cropping system. This work was conducted in the experimental area of SIPA (Integrated system of agro ecological production), at the county of Serop?dica RJ, with the aim of valuate the growth , the water needs, and the efficiency of the use of the water by the bell pepper culture (Capsicum annuum. L ), at the conventional (PC) and the direct systems of soiling. The conventional system consisted of soil prepare with rotational hoe tied to a micro tractor, and the direct soiling, being done after the occupation of the area with a combination of Sorghum bicolor and Crotal?ria acroleura, that was grazed at the transplantation of the bell pepper s seedlings without previous soil preparation. The same fertilization and cultural practices permitted by the agro ecological handling, was used in both systems. The two systems tested, received sprinkler irrigation, and the determination of the water s blade, was made by monitoring with TDR (Time Domain Reflectometry), calibrated for the soil conditions of the experimental area. The splits were also monitorated by a tensiometer at a 50 cm. deep. Collects were made at intervals of 14 days, with the aim of foliar area evaluation, biomass accumulation by the parts of the plant, along the entire cycle, being also evaluated the crop production at the two systems of soiling. By the adjustment of the IAF (Foliar Area Indices ) and the biomass accumulated by the plant at the two systems of planting in function of accumulated day-degree (GDA), was verified that 1533 GDA was necessary to complete the productive cycle, reaching the top of accumulated biomass at 1059 and 1148 GDA, at PC and PD respectivement. There were no differences between the systems of planting, in respect of the growth rate and the productivity, however the PD system gave less competition between spontaneous vegetation and the bell pepper crop, reducing in 60% the necessity of hand labor at the firsts weddings. The PD system raise the efficiency of the use of water (EUA) by the crop reducing in 47,5 mm. the blade applied during its cycle, in relation of PC. The irrigation handling using TDR, provide an meaning EUA of 4,4 Kg.m-3, above the means of 1,5 to 3,0Kg.m-3, recommended by Doorenbos & Kassam (1994). The culture coefficients (Kc) recommended for the bell pepper crop, were evaluated together with the calculated coefficients using some methodologies proposed in this work, and was noted that the estimated Kc s values of the production cycles (ETc cycle) and by the Kc curve (graphic ETc) estimated during the culture cycle, were more appropriated for the calculation of the evapotranspiration of the crop. The estimation of reference evapotranspiration (ETo), by the pan class A method, made possible means close to those estimated by the Penman-Monteith model witch is recommended by FAO as standard. Therefore, the pan class A method, can be utilized in the estimated ETo, at same conditions of the experiment when there are no data of climate for the Penman-Monteith model use. Associated tensiometry and TDR for irrigation management, showed to be an essential practice when looking for raising the efficiency of the use of water. Este trabalho foi realizado na ?rea experimental do SIPA (Sistema Integrado de produ??o Agroecol?gica), localizada no munic?pio de Serop?dica-RJ, com o objetivo de avaliar o crescimento, as necessidades h?dricas e a efici?ncia no uso da ?gua pela cultura do piment?o (Capsicum annuum. L), nos sistemas de plantio convencional (PC) e direto (PD). O sistema convencional consistiu de preparo de solo com enxada rotativa acoplada a micro-trator e o plantio direto, na ocupa??o da ?rea com pr?-cultivo, utilizando o cons?rcio Sorghum bicolor e Crotal?ria acroleura, os quais foram ro?ados por ocasi?o do transplante das mudas de piment?o, sem o preparo pr?vio do solo. Em ambos os tratamentos a cultura recebeu a mesma aduba??o de cova e tratos culturais permitidos pelo manejo agroecol?gico. Nos dois sistemas de plantio a cultura foi irrigada por aspers?o, e a determina??o das l?minas aplicadas, foi realizada atrav?s do monitoramento com TDR (Reflectometria no dom?nio do tempo), calibrado para as condi??es de solo da ?rea experimental. As parcelas foram monitoradas tamb?m por tensi?metro no perfil de 50cm de profundidade. Foram realizadas coletas em intervalos de 14 dias com a finalidade de avaliar a ?rea foliar e acumulo de biomassa pelas partes da planta, durante todo o seu ciclo, sendo avaliado tamb?m a produ??o pela cultura nos dois sistemas de plantio. Por meio do ajuste do IAF e da biomassa acumulada pela planta nos dois sistemas de plantio em fun??o de graus-dia acumulado (GDA), constatou-se que s?o necess?rios 1533 GDA para que a planta complete o seu ciclo produtivo, atingindo o m?ximo de biomassa acumulada aos 1059 e 1148 GDA, no PC e PD, respectivamente. Os sistemas de plantio n?o diferiram significativamente entre si com rela??o ?s taxas de crescimento e produtividade, entretanto o plantio direto proporcionou menor competi??o da vegeta??o espont?nea com a cultura, reduzindo em 60 % a necessidade de m?o-de-obra nas primeiras capinas. O PD aumentou a efici?ncia no uso da ?gua (EUA), pela cultura, reduzindo em 47,5mm a l?mina aplicada durante o seu ciclo, em rela??o ao PC. O manejo da irriga??o utilizando o TDR, proporcionou a EUA m?dia de 4,4kg.m-3, acima dos valores 1,5 a 3,0kg.m-3 propostos por Doorenbos e Kassam (1994). Os Coeficientes de cultivo (Kc) recomendados para a cultura, foram avaliados juntamente com os calculados por v?rias metodologias propostas neste trabalho, verificando-se que os valores de Kc estimados em fun??o dos ciclos de produ??o (ETc ciclo) e pela curva de Kc (ETc gr?fico) estimados durante o ciclo da cultura, se mostraram mais adequados ao c?lculo da evapotranspira??o da cultura. A estimativa da evapotranspira??o refer?ncia (ETo), pelo m?todo do tanque classe A , possibilitou valores pr?ximos aos estimados pelo modelo de Penman-Monteith recomendado pela FAO como padr?o. Portanto o m?todo do tanque classe A poder? ser utilizado na estimativa da ETo, em condi??es semelhantes a do experimento, quando n?o houver disponibilidade de dados clim?ticos para o uso do modelo de Penman- Monteith. O uso da tensiometria associado ao TDR no manejo de irriga??o revelou ser uma pr?tica indispens?vel, quando se almeja aumentar a efici?ncia no uso da ?gua.

Direito e Justi��a, v. 16 n. 2 (2002)