On the Information Rates of the Plenoptic Function

The {\it plenoptic function} (Adelson and Bergen, 91) describes the visual information available to an observer at any point in space and time. Samples of the plenoptic function (POF) are seen in video and in general visual content, and represent large amounts of information. In this paper we propose a stochastic model to study the compression limits of the plenoptic function. In the proposed framework, we isolate the two fundamental sources of information in the POF: the one representing the camera motion and the other representing the information complexity of the "reality" being acquired and transmitted. The sources of information are combined, generating a stochastic process that we study in detail. We first propose a model for ensembles of realities that do not change over time. The proposed model is simple in that it enables us to derive precise coding bounds in the information-theoretic sense that are sharp in a number of cases of practical interest. For this simple case of static realities and camera motion, our results indicate that coding practice is in accordance with optimal coding from an information-theoretic standpoint. The model is further extended to account for visual realities that change over time. We derive bounds on the lossless and lossy information rates for this dynamic reality model, stating conditions under which the bounds are tight. Examples with synthetic sources suggest that in the presence of scene dynamics, simple hybrid coding using motion/displacement estimation with DPCM performs considerably suboptimally relative to the true rate-distortion bound.Comment: submitted to IEEE Transactions in Information Theor

Estudo comparativo do tempo de piscadas entre adultos jovens e adultos usuários de monitor de microcomputador em ambiente climatizado

OBJECTIVE: Investigate the average blinking time in conversation and in Video Display Terminal use of young adults and adults in the presbyopic age group. METHODS: A transversal analytical study in a readily accessible sample consisting of Volkswagen do Brasil - Curitiba, Paraná employees was performed. The cohort group consisted of 108 subjects divided into two age groups: Group 1, the young adult group (age range 20-39): 77 employees, mean age of 30.09 ± 5.09; Group 2, the presbyopic adult group, (age range 40-53): 31 employees, mean age of 44.17 ± 3. Subjects under 18 years of age, with a history of ocular disorders, contact lens wearers and computer non-users were excluded. The subjects had their faces filmed for 10 minutes in conversation and VDT reading. Student's t-test was used and the statistical significance level was 95%. RESULTS: The average time between blinks in Group 1 for conversation and VDT reading was 5.16 ± 1.83 and 10.42 ± 7.78 seconds, respectively; in Group 2. 4,9 ± 1.49 and 10.46 ± 5.54 seconds. In both age groups, the time between blinks in VDT reading situations was higher (p<0.0001). There was no statistically meaningful difference for conversation and VDT reading situations when the two studied age groups were compared (p>0.05). CONCLUSION: There was an increase in the blinking time between young adults and the presbyopic group in VDT use situations when compared with reading situations. The difference in the blinking frequency between young adults and the presbyopic group in VDT use and reading situations was not statistically significant.OBJETIVOS: Investigar o intervalo entre as piscadas em adultos jovens e em présbitas, durante conversação e leitura no monitor do computador. MÉTODOS: Realizou-se estudo transversal, analítico, em amostra prontamente acessível, composta por funcionários da Volkswagen do Brasil, em Curitiba (Paraná-Brasil). A amostra foi dividida em dois grupos de acordo com a idade: grupo 1 (20-39 anos); grupo 2 (40-53 anos). Foram excluídos menores de 18 anos, portadores de doenças oculares, usuários de lentes de contato e não usuários de computador. Os participantes tiveram suas faces filmadas por 10 minutos durante atividades de conversação e leitura no monitor do computador. Utilizou-se teste t de Student,com nível de significância de 95%. RESULTADOS: A amostra compôs-se de 108 indivíduos, sendo o grupo 1 com 77 indivíduos, com idade média 30,09 ± 5,09 anos e grupo 2 com 31 indivíduos, com idade média 44,17 ± 3 anos. O tempo médio entre as piscadas, no grupo 1, em conversação foi de 5,16 ± 1,83 e leitura no monitor de 10,42 ± 7,78 segundos; no grupo 2, em conversação foi de 4,9 ± 1,49 e leitura no monitor de 10,46 ± 5,54 segundos. Encontrou-se distância maior entre as piscadas, durante a leitura no monitor (p<0,0001) nos dois grupos etários. Conferindo os resultados encontrados nos dois grupos, nas situações de conversação e leitura no monitor, não houve diferença estatisticamente significativa (p>0,05). CONCLUSÃO: Houve um aumento no intervalo entre as piscadas, em adultos jovens e em présbitas, durante a leitura em monitor quando comparada com situação de conversação. Não se evidenciou diferença estatisticamente significativa entre os participantes dos dois grupos, nas situações de conversação e leitura no monitor

Finite-Dimensionality of Tempered Random Uniform Attractors

Finite-dimensional attractors play an important role in finite-dimensional reduction of PDEs in mathematical modelization and numerical simulations. For non-autonomous random dynamical systems, Cui and Langa (J Differ Equ, 263:1225–1268, 2017) developed a random uniform attractor as a minimal compact random set which provides a certain description of the forward dynamics of the underlying system by forward attraction in probability. In this paper, we study the conditions that ensure a random uniform attractor to have finite fractal dimension. Two main criteria are given, one by a smoothing property and the other by a squeezing property of the system, and neither of the two implies the other. The upper bound of the fractal dimension consists of two parts: the fractal dimension of the symbol space plus a number arising from the smoothing/squeezing property. As an illustrative application, the random uniform attractor of a stochastic reaction–diffusion equation with scalar additive noise is stud ied, for which the finite-dimensionality in L2 is established by the squeezing approach and that in H1 0 by the smoothing framework. In addition, a random absorbing set that absorbs itself after a deterministic period of time is also constructed

Crosswell seismic tomographic inversion using NSGA II

In the present paper, the solution of the seismic data inversion problem through multi-objective optimization with NSGA II is addressed. The seismic inversion consists of estimating the slowness of rocks in the subsurface from the travel times of the waves through the transmitters and receivers of the seismic waves. The inversion process uses the multi-objective optimization technique, in which it is necessary to estimate the trade-off between the misfit functional and the stabilizing constraint. The constraint used was the classic first-order Tikhonov. A synthetic model of inclined layers was chosen. The results obtained were acceptable. Based on the graph of the cumulative errors related to the solution, it was estimated correctly, that is, the optimization method used was effective to obtain acceptable results, in addition to the constraint solving the instability problem of the inverse problem treated. Another important result was the achievement of a convergence curve on the Pareto frontier, an important result for future research.Comment: 14 pages, 12 figure

Comparative Study of Methods for Estimating Evapotranspiration Reference in ParanaAba City, Brazil

This study aimed to was evaluating the performance of 30 methods to estimate reference evapotranspiration ET0 to the city of Parana ba Brazil The meteorological data was removed from National Institute of Meteorology on the period of six year March 2008 to February 2014 The method taken as standard was Penman-Monteith-FAO56 and the comparison of results was by the coefficients of determination r coefficients a and b of the linear regressions estimate of standard-error Willmott s index of agreement d Pearson correlation coefficient r and reliable coefficient c The better methods to ET0 estimate was Penman-Original Stephens-Stewart Priestley-Taylor Hicks-Hess Turc Liquid-Radiation Thornthwaite-Modified Temperature-Radiation Penman-FAO24 Abtew and Camargo The Camargo method should be preferred when only air temperatures data have The methods Blaney-Criddle-FAO24 and Hamon should receive calibration for be utilized on the estimate of ET0 in Parana ba cit

Vascular Dysfunction as Target Organ Damage in Animal Models of Hypertension

Endothelial dysfunction is one of the main characteristics of chronic hypertension and it is characterized by impaired nitric oxide (NO) bioactivity determined by increased levels of reactive oxygen species. Endothelial function is usually evaluated by measuring the vasodilation induced by the local NO production stimulated by external mechanical or pharmacological agent. These vascular reactivity tests may be carried out in different models of experimental hypertension such as NO-deficient rats, spontaneously hypertensive rats, salt-sensitive rats, and many others. Wire myograph and pressurized myograph are the principal methods used for vascular studies. Usually, increasing concentrations of the vasodilator acetylcholine are added in cumulative manner to perform endothelium-dependent concentration-response curves. Analysis of vascular mechanics is relevant to identify arterial stiffness. Both endothelial dysfunction and vascular stiffness have been shown to be associated with increased cardiovascular risk

Os Alimentos Ofertados pelo Programa Nacional de Alimentação Escolar (PNAE) no Município de Foz do Iguaçu, no Período de 2016-2022: Desafios e Perspectivas

Trabalho de Conclusão de Curso apresentado ao Instituto Latino-Americano de Economia, Sociedade e Política da Universidade Federal da Integração Latino-Americana, como requisito parcial à obtenção do título de Bacharel em Desenvolvimento Rural e Segurança Alimentar.O Programa Nacional de Alimentação Escolar (PNAE) visa à transferência de recursos financeiros destinados a compra de alimentos com objetivo de suprir parcialmente as necessidades alimentares de estudantes de todas as etapas da educação básica pública. Favorece a aquisição de alimentos produzidos por Agricultores Familiares, facilita a articulação entre agricultores e o governo e fornece alimentos seguros e adequados promovendo hábitos saudáveis. O presente estudo teve como objetivo identificar a variedade e classificar por nível de processamento de acordo com a NOVA classificação do Guia Alimentar para a população brasileira, os alimentos ofertados pelo PNAE Municipal de Foz do Iguaçu, no período de 2016 a 2022; bem como analisar a participação dos agricultores familiares na oferta de produtos. A metodologia consiste em um estudo descritivo e exploratório, realizado a partir de pesquisa bibliográfica utilizando artigos, documentos governamentais obtidos no Portal da transparência e a aplicação de 02(duas) entrevistas sendo uma gestora pública Nutricionista da Secretaria de Educação do Município e um gerente financeiro de uma cooperativa local. Alguns dos resultados obtidos na pesquisa são que as aquisições de alimentos in natura ou minimamente processados aumentaram ocorrendo principalmente por meio de processos licitatórios, por outro lado a Chamada Publica destinada a compra de alimentos oriundos da agricultura familiar se mantem estável com tendência a diminuir em relação à variedade de produtos. Nota-se que apesar de leis que promovem a aquisição de alimentos oriundos da agricultura familiar a maior parte do recurso investido no programa destina-se a compras através dos Pregões. As entrevistas identificaram que há dificuldades para aquisição de alimentos da cooperativa, um dos motivos mencionados é a falta de profissionais de Assistência técnica e Extensão rural e o acesso a outras politicas públicas. Neste sentido, entendemos as políticas públicas como mecanismos essenciais para garantir a Segurança Alimentar e fomentar a agricultura familiar contribuindo para o surgimento de associações e cooperativas, estimulando hábitos alimentares saudáveis e fornecendo o apoio técnico necessário

Revisiting the Random Subset Sum Problem

International audienceThe average properties of the well-known Subset Sum Problem can be studied by the means of its randomised version, where we are given a target value $z$, random variables $X_1, \ldots, X_n$, and an error parameter $\varepsilon > 0$, and we seek a subset of the $X_i$'s whose sum approximates $z$ up to error $\varepsilon$.In this setup, it has been shown that, under mild assumptions on the distribution of the random variables, a sample of size $\mathcal{O}\left(\log (1/\varepsilon)\right)$ suffices to obtain, with high probability, approximations for all values in $[-1/2, 1/2]$. Recently, this result has been rediscovered outside the algorithms community, enabling meaningful progress in other fields. In this work we present an alternative proof for this theorem, with a more direct approach and resourcing to more elementary tools, in the hope of disseminating it even further

Mechanical characterization of Iroko wood using small specimens

Despite their favorable physical and mechanical properties for structural use, tropical woods, such as Iroko (Milicia excelsa), present knowledge gaps to be filled mainly about their mechanical characterization, which currently limit their use or result in under- or overdimensioned structural elements. Visual classification, one of the most used methods for characterizing wood, is inaccurate in the case of Iroko due to the wide variety of geographical locations in which this species can be found. In addition, mechanical characterization using test pieces with structural dimensions leads to high and impractical costs. In this context, this study aims to verify the mechanical properties of Iroko (imported from the Republic of the Congo) from small size specimens, a process that is currently standardized only for softwoods, and to verify the correlation of different properties through bending properties and ultrasound tests. Prior to the bending tests, the speed of propagation of ultrasonic waves was measured using the direct method. The results obtained show a good correlation between density and bending properties and the velocity of propagation of ultrasonic waves