826 research outputs found

    Thread Counting in Plain Weave for Old Paintings Using Semi-Supervised Regression Deep Learning Models

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    In this work, the authors develop regression approaches based on deep learning to perform thread density estimation for plain weave canvas analysis. Previous approaches were based on Fourier analysis, which is quite robust for some scenarios but fails in some others, in machine learning tools, that involve pre-labeling of the painting at hand, or the segmentation of thread crossing points, that provides good estimations in all scenarios with no need of pre-labeling. The segmentation approach is time-consuming as the estimation of the densities is performed after locating the crossing points. In this novel proposal, we avoid this step by computing the density of threads directly from the image with a regression deep learning model. We also incorporate some improvements in the initial preprocessing of the input image with an impact on the final error. Several models are proposed and analyzed to retain the best one. Furthermore, we further reduce the density estimation error by introducing a semi-supervised approach. The performance of our novel algorithm is analyzed with works by Ribera, Vel\'azquez, and Poussin where we compare our results to the ones of previous approaches. Finally, the method is put into practice to support the change of authorship or a masterpiece at the Museo del Prado.Comment: 21 page

    Tree expectation propagation for ml decoding of LDPC codes over the BEC

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    We propose a decoding algorithm for LDPC codes that achieves the maximum likelihood (ML) solution over the bi- nary erasure channel (BEC). In this channel, the tree-structured expectation propagation (TEP) decoder improves the peeling decoder (PD) by processing check nodes of degree one and two. However, it does not achieve the ML solution, as the tree structure of the TEP allows only for approximate inference. In this paper, we provide the procedure to construct the structure needed for exact inference. This algorithm, denoted as generalized tree-structured expectation propagation (GTEP), modifies the code graph by recursively eliminating any check node and merging this information in the remaining graph. The GTEP decoder upon completion either provides the unique ML solution or a tree graph in which the number of parent nodes indicates the multiplicity of the ML solution. We also explain the algorithm as a Gaussian elimination method, relating the GTEP to other ML solutions. Compared to previous approaches, it presents an equivalent complexity, it exhibits a simpler graphical message-passing procedure and, most interesting, the algorithm can be generalized to other channels

    Statistical Audit via Gaussian Mixture Models in Business Intelligence Systems

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    A Business Intelligence (BI) System employs tools from several areas of knowledge for the collection, integration and analysis of data to improve business decision making. The Brazilian Ministry of Planning, Budget and Management (MP) uses a BI System designed with the University of Bras´ılia to ascertain irregularities on the payroll of the Brazilian federal government, performing audit trails on selected items and fields of the payroll database. This current auditing approach is entirely deterministic, since the audit trails look for previously known signatures of irregularities which are composed by means of an ontological method used to represent auditors concept maps. In this work, we propose to incorporate a statistical filter in this existing BI system in order to increase its performance in terms of processing speed and overall system responsiveness. The proposed statistical filter is based on a generative Gaussian Mixture Model (GMM) whose goal is to provide a complete stochastic model of the process, specially the latent probability density function of the generative mixture, and use that model to filter the most probable payrolls. Inserting this statistical filter as a pre-processing stage preceding the deterministic auditing showed to be effective in reducing the amount of data to be analyzed by the audit trails, despite the penalty fee intrinsically associated with stochastic models due to the false negative outcomes that are not further processed. In our approach, gains obtained with the proposed pre-processing stage overcome impacts from false negative outcomes

    Adherencia a la dieta mediterránea en adultos inactivos, practicantes de ciclo indoor y ciclistas aficionados

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    Introducción: existe información limitada sobre la relación entre la adherencia a la dieta mediterránea (ADM) y la práctica deportiva. Objetivo: determinar la posible asociación de la práctica deportiva y el volumen de entrenamiento en bicicleta con la ADM y la influencia de la proximidad de una prueba ciclodeportiva sobre la ADM. Material y métodos: una primera evaluación de la ADM en 785 (84 mujeres) ciclistas aficionados (volumen = 7 horas/semana), 514 (224 mujeres) practicantes de ciclo indoor (volumen: 2-6 horas/semana) y 718 (411 mujeres) adultos inactivos fue desarrollada en mayo, coincidiendo con la participación de los ciclistas en una prueba ciclodeportiva. Una submuestra de 359 ciclistas y 148 inactivos fueron evaluados nuevamente en noviembre, en fecha alejada de la prueba ciclodeportiva. Se utilizó el cuestionario MEDAS-14 para valorar la ADM y un cuestionario autodiseñado para evaluar el volumen de entrenamiento. Resultados: un 40% de los sujetos evidenció alta ADM. En ambos sexos, los deportistas mostraron mayor ADM que los inactivos, con los mejores índices para los grupos de ciclistas (p < 0, 001). La relación entre la ADM y el volumen de entrenamiento fue débil (hombres: r = 0, 137, mujeres: r = 0, 173; p < 0, 001). La ADM de los ciclistas disminuyó de mayo a noviembre (p < 0, 001) sin cambios en los sujetos inactivos (p = 0, 535). Conclusiones: la práctica deportiva en bicicleta se asocia con una mayor ADM con limitada influencia del volumen de entrenamiento y con efectos positivos transitorios de la participación en una prueba ciclodeportiva. Introduction: There is limited information referred to the relationship between adherence to the Mediterranean Diet (AMD) and sports practice. Objective: To determinate the association of cycling practice and cycling training volume with the AMD and the influence of the participation in a high-demand cyclist event on the AMD. Material and methods: A first evaluation of AMD in 785 (84 women) amateur cyclists (volume: = 7 hours/week), 514 (224 women) indoor cycling practitioners (volume: 2-6 hours/week) and 718 (411 women) inactive adults was conducted in May coinciding with the participation of cyclists in a cycling event. A subsample of 359 cyclists and 148 inactive subjects agreed to be retested in November, far from the cycling event date. The MEDAS-14 questionnaire was used to assess the AMD and a self-designed questionnaire was used to assess the volume of training. Results: 40% of subjects showed high AMD. In both sexes, athletes showed higher AMD than inactive subjects, with the highest indexes for groups of cyclists (p < 0.001). The relationship between AMD and training volume was weak (men: r = 0.137, women: r = 0.173; p < 0.001). The AMD of cyclists decreased from May to November (p < 0.001) with no significant changes in inactive subjects (p = 0.535). Conclusions: Cycling is associated to higher values of AMD with a limited influence of training volume and transient positive effects of participation in a cycling endurance event

    Explaining telecoms and electricity internationalization in the European Union: a political economy perspective

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    One consequence of the liberalization of certain services in the European Union was that a number of formerly inward-looking incumbents in telecommunications and electricity rapidly transformed themselves into some of the world’s leading Multinationals. However, the precise relationship between liberalization and incumbent internationalization is contested. This article tests three persuasive arguments derived from the political economy literature on this relationship. The first claims that those incumbents most exposed to domestic liberalization would internationalise most. The second asserts the opposite: incumbents operating where liberalization was restricted could exploit monopolistic rents to finance their aggressive internationalisation. The third argument claims that a diversity of paths will be adopted by countries and incumbents vis-à-vis liberalization and internationalization. Using correlation and cluster analysis of the sample of all major EU telecoms and electricity incumbent Multinationals evidence is found in favour of the third hypothesis. Internationalization as a response to liberalization took diverse forms in terms of timing and extent and this is best explained using a country, sector and firm logic

    After the epidemic: Zika virus projections for Latin America and the Caribbean

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    Background: Zika is one of the most challenging emergent vector-borne diseases, yet its future public health impact remains unclear. Zika was of little public health concern until recent reports of its association with congenital syndromes. By 3 August 2017 ~217,000 Zika cases and ~3,400 cases of associated congenital syndrome were reported in Latin America and the Caribbean. Some modelling exercises suggest that Zika virus infection could become endemic in agreement with recent declarations from the The World Health Organisation. Methodology/Principal findings: We produced high-resolution spatially-explicit projections of Zika cases, associated congenital syndromes and monetary costs for Latin America and the Caribbean now that the epidemic phase of the disease appears to be over. In contrast to previous studies which have adopted a modelling approach to map Zika potential, we project case numbers using a statistical approach based upon reported dengue case data as a Zika surrogate. Our results indicate that ~12.3 (0.7–162.3) million Zika cases could be expected across Latin America and the Caribbean every year, leading to ~64.4 (0.2–5159.3) thousand cases of Guillain-Barré syndrome and ~4.7 (0.0–116.3) thousand cases of microcephaly. The economic burden of these neurological sequelae are estimated to be USD ~2.3 (USD 0–159.3) billion per annum. Conclusions/Significance: Zika is likely to have significant public health consequences across Latin America and the Caribbean in years to come. Our projections inform regional and federal health authorities, offering an opportunity to adapt to this public health challenge

    The Smallest Known Genomes of Multicellular and Toxic Cyanobacteria: Comparison, Minimal Gene Sets for Linked Traits and the Evolutionary Implications

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    Cyanobacterial morphology is diverse, ranging from unicellular spheres or rods to multicellular structures such as colonies and filaments. Multicellular species represent an evolutionary strategy to differentiate and compartmentalize certain metabolic functions for reproduction and nitrogen (N2) fixation into specialized cell types (e.g. akinetes, heterocysts and diazocytes). Only a few filamentous, differentiated cyanobacterial species, with genome sizes over 5 Mb, have been sequenced. We sequenced the genomes of two strains of closely related filamentous cyanobacterial species to yield further insights into the molecular basis of the traits of N2 fixation, filament formation and cell differentiation. Cylindrospermopsis raciborskii CS-505 is a cylindrospermopsin-producing strain from Australia, whereas Raphidiopsis brookii D9 from Brazil synthesizes neurotoxins associated with paralytic shellfish poisoning (PSP). Despite their different morphology, toxin composition and disjunct geographical distribution, these strains form a monophyletic group. With genome sizes of approximately 3.9 (CS-505) and 3.2 (D9) Mb, these are the smallest genomes described for free-living filamentous cyanobacteria. We observed remarkable gene order conservation (synteny) between these genomes despite the difference in repetitive element content, which accounts for most of the genome size difference between them. We show here that the strains share a specific set of 2539 genes with >90% average nucleotide identity. The fact that the CS-505 and D9 genomes are small and streamlined compared to those of other filamentous cyanobacterial species and the lack of the ability for heterocyst formation in strain D9 allowed us to define a core set of genes responsible for each trait in filamentous species. We presume that in strain D9 the ability to form proper heterocysts was secondarily lost together with N2 fixation capacity. Further comparisons to all available cyanobacterial genomes covering almost the entire evolutionary branch revealed a common minimal gene set for each of these cyanobacterial traits

    Search for pair-produced vector-like leptons in final states with third-generation leptons and at least three b quark jets in proton-proton collisions at √s = 13 TeV

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