224 research outputs found

    Toulouse Hyperspectral Data Set: a benchmark data set to assess semi-supervised spectral representation learning and pixel-wise classification techniques

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    Airborne hyperspectral images can be used to map the land cover in large urban areas, thanks to their very high spatial and spectral resolutions on a wide spectral domain. While the spectral dimension of hyperspectral images is highly informative of the chemical composition of the land surface, the use of state-of-the-art machine learning algorithms to map the land cover has been dramatically limited by the availability of training data. To cope with the scarcity of annotations, semi-supervised and self-supervised techniques have lately raised a lot of interest in the community. Yet, the publicly available hyperspectral data sets commonly used to benchmark machine learning models are not totally suited to evaluate their generalization performances due to one or several of the following properties: a limited geographical coverage (which does not reflect the spectral diversity in metropolitan areas), a small number of land cover classes and a lack of appropriate standard train / test splits for semi-supervised and self-supervised learning. Therefore, we release in this paper the Toulouse Hyperspectral Data Set that stands out from other data sets in the above-mentioned respects in order to meet key issues in spectral representation learning and classification over large-scale hyperspectral images with very few labeled pixels. Besides, we discuss and experiment the self-supervised task of Masked Autoencoders and establish a baseline for pixel-wise classification based on a conventional autoencoder combined with a Random Forest classifier achieving 82% overall accuracy and 74% F1 score. The Toulouse Hyperspectral Data Set and our code are publicly available at https://www.toulouse-hyperspectral-data-set.com and https://www.github.com/Romain3Ch216/tlse-experiments, respectively.Comment: 17 pages, 13 figure

    p3^3VAE: a physics-integrated generative model. Application to the semantic segmentation of optical remote sensing images

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    The combination of machine learning models with physical models is a recent research path to learn robust data representations. In this paper, we introduce p3^3VAE, a generative model that integrates a perfect physical model which partially explains the true underlying factors of variation in the data. To fully leverage our hybrid design, we propose a semi-supervised optimization procedure and an inference scheme that comes along meaningful uncertainty estimates. We apply p3^3VAE to the semantic segmentation of high-resolution hyperspectral remote sensing images. Our experiments on a simulated data set demonstrated the benefits of our hybrid model against conventional machine learning models in terms of extrapolation capabilities and interpretability. In particular, we show that p3^3VAE naturally has high disentanglement capabilities. Our code and data have been made publicly available at https://github.com/Romain3Ch216/p3VAE.Comment: 21 pages, 11 figures, submitted to the International Journal of Computer Visio

    Myths and lessons of liberal intervention: The British campaign for the abolition of the Atlantic slave trade to Brazil

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    This is the Pre-print version of the Article. The official published version can be accessed from the link below - Copyright @ 2012 Martinus NijhoffThis article takes issue with recent references to the British nineteenth century campaign for the abolition of the trans-Atlantic slave trade to Brazil that serve to bolster interventionist or imperialist agendas. In particular, such accounts reproduce two and a half myths about the campaign: that it can serve as a model for the present age; that the success of the campaign can be explained through the actions of the intervening party alone (with a corresponding neglect of those of the ‘target’ state); and the half-myth that the campaign’s success was due to military action (at the expense of institutional (legal) and normative factors and the capacity of the target state). I argue instead that this case – and interventions more generally – would benefit from an analysis that considers the role of force in relation to a series of residual institutional and cultural constraints within the liberal state and to political conditions in the target state. In light of the complexities and contingencies that these factors present the underlying lesson is that military force should be used sparingly, if at all

    A deeper look at the association between childhood maltreatment and reflective functioning

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    Childhood maltreatment is theorized as impeding the development of reflective functioning (RF; ability to perceive and interpret oneself and others in terms of mental states). However, previous research typically failed to support this association or yielded small sized and mixed associations. This study aims to provide a deeper look at the association between childhood maltreatment and RF by characterizing two non-mentalizing categories. One-hundred-and-sixteen pregnant women (mean age = 27.62, SD = 4.52) from the community (48.3% with a university degree, 96.5% in a relationship with the other parent) retrospectively reported on childhood abuse and neglect using the Childhood Trauma Questionnaire. They also participated in the Adult Attachment Interview subsequently coded using the Reflective Functioning Scale. Participants with poor to low RF were allocated to one of two groups (disavowal-distancing or distorted-inconsistent) using indicators provided in the RF Scale. No association was found between childhood maltreatment and overall RF when controlling for education level. A multinomial logistic regression revealed that childhood maltreatment was strongly predictive of a disrupted, over-analytical and inconsistent reflection about mental states but not of a tendency to discourse little about mental states. This tendency was rather only predicted by education level. Findings suggest that childhood maltreatment would lead to specific impairments in RF and that not considering how individuals fail to mentalize about attachment relationships may mask strong associations between RF and its determinants and correlates, including childhood maltreatment

    Success in Developing Regions: World Records Evolution through a Geopolitical Prism

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    A previous analysis of World Records (WR) has revealed the potential limits of human physiology through athletes' personal commitment. The impact of political factors on sports has only been studied through Olympic medals and results. Here we studied 2876 WR from 63 nations in four summer disciplines. We propose three new indicators and show the impact of historical, geographical and economical factors on the regional WR evolution. The south-eastward path of weighted annual barycenter (i.e. the average of country coordinates weighting by the WR number) shows the emergence of East Africa and China in WR archives. Home WR ratio decreased from 79.9% before the second World War to 23.3% in 2008, underlining sports globalization. Annual Cumulative Proportions (ACP, i.e. the cumulative sum of the WR annual rate) highlight the regional rates of progression. For all regions, the mean slope of ACP during the Olympic era is 0.0101, with a maximum between 1950 and 1989 (0.0156). For European countries, this indicator reflects major historical events (slowdown for western countries after 1945, slowdown for eastern countries after 1990). Mean North-American ACP slope is 0.0029 over the century with an acceleration between 1950 and 1989 at 0.0046. Russia takes off in 1935 and slows down in 1988 (0.0038). For Eastern Europe, maximal progression is seen between 1970 and 1989 (0.0045). China starts in 1979 with a maximum between 1990 and 2008 (0.0021), while other regions have largely declined (mean ACP slope for all other countries  = 0.0011). A similar trend is observed for the evolution of the 10 best performers. The national analysis of WR reveals a precise and quantifiable link between the sport performances of a country, its historical or geopolitical context, and its steps of development

    CoMMA Corporate Memory Management through Agents Corporate Memory Management through Agents: The CoMMA project final report

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    This document is the final report of the CoMMA project. It gives an overview of the different search activities that have been achieved through the project. First, a description of the general requirements is proposed through the definition of two scenarios. Then it shows the different technical aspects of the projects and the solution that has been proposed and implemented

    Entangling single photons on a beamsplitter

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    We report on a scheme for the creation of time-bin entangled states out of two subsequent single photons. Both photons arrive on the same input port of a beamsplitter and the situation in which the photons leave the beamsplitter on different output ports is post-selected. We derive a full quantum mechanical analysis of such time-bin entanglement for emitters subject to uncorrelated dephasing processes and apply this model to sequential single photons emerging from a single semiconductor quantum dot. Our results indicate that the visibility of entanglement is degraded by decoherence effects in the quantum dot, but can be restored by use of CQED effects, namely the Purcell effect.Comment: Accepted EPJ

    Corporate Memory Management through Agents: The CoMMA project final report

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    This document is the final report of the CoMMA project. It gives an overview of the different search activities that have been achieved through the project. First, a description of the general requirements is proposed through the definition of two scenarios. Then it shows the different technical aspects of the projects and the solution that has been proposed and implemented

    CC9 Livestock-Associated Staphylococcus aureus Emerges in Bloodstream Infections in French Patients Unconnected With Animal Farming

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    We report 4 bloodstream infections associated with CC9 agr type II Staphylococcus aureus in individuals without animal exposure. We demonstrate, by microarray analysis, the presence of egc cluster, fnbA, cap operon, lukS, set2, set12, splE, splD, sak, epiD, and can, genomic features associated with a high virulence potential in human
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