2,724 research outputs found

    Laplace operators on differential forms over configuration spaces

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    Spaces of differential forms over configuration spaces with Poisson measures are constructed. The corresponding Laplacians (of Bochner and de Rham type) on forms and associated semigroups are considered. Their probabilistic interpretation is given

    The anatomy of the 2019 Chilean social unrest

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    We analyze the 2019 Chilean social unrest episode, consisting of a sequence of events, through the lens of an epidemic-like model that considers global contagious dynamics. We adjust the parameters to the Chilean social unrest aggregated public data available from the Undersecretary of Human Rights, and observe that the number of violent events follows a well-defined pattern already observed in various public disorder episodes in other countries since the sixties. Although the epidemic-like models display a single event that reaches a peak followed by an exponential decay, we add standard perturbation schemes that may produce a rich temporal behavior as observed in the 2019 Chilean social turmoil. Although we only have access to aggregated data, we are still able to fit it to our model quite well, providing interesting insights on social unrest dynamics.Comment: To appear in Chao

    Islands in Multiverse Models

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    We consider multiverse models in two-dimensional linear dilaton-gravity theories as toy models of false vacuum eternal inflation. Coupling conformal matter we calculate the Von Neumann entropy of subregions. When these are sufficiently large we find that an island develops covering most of the rest of the multiverse, leading to a Page-like transition. This resonates with a description of multiverse models in semiclassical quantum cosmology, where a measure for local predictions is given by saddle point geometries which coarse-grain over any structure associated with eternal inflation beyond one's patch.Comment: 47 pages, 18 figures; v2 reflects accepted versio

    The generalized second law in the emergent universe

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    This paper studies whether the generalized second law of thermodynamics is fulfilled in the transition from a generic initial Einstein static phase to the inflationary phase, with constant Hubble rate, and from the end of the latter to the conventional era of thermal radiation dominated expansion. As it turns out, the said law is satisfied provided the radiation component does not largely contribute to the total energy of the static phase.Comment: 8 pages, 1 figure; to be published in Phys. Letters

    Neuromorphic Computing for Interactive Robotics: A Systematic Review

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    Modelling functionalities of the brain in human-robot interaction contexts requires a real-time understanding of how each part of a robot (motors, sensors, emotions, etc.) works and how they interact all together to accomplish complex behavioural tasks while interacting with the environment. Human brains are very efficient as they process the information using event-based impulses also known as spikes, which make living creatures very efficient and able to outperform current mainstream robotic systems in almost every task that requires real-time interaction. In recent years, combined efforts by neuroscientists, biologists, computer scientists and engineers make it possible to design biologically realistic hardware and models that can endow the robots with the required human-like processing capability based on neuromorphic computing and Spiking Neural Network (SNN). However, while some attempts have been made, a comprehensive combination of neuromorphic computing and robotics is still missing. In this article, we present a systematic review of neuromorphic computing applications for socially interactive robotics.We first introduce the basic principles, models and architectures of neuromorphic computation. The remaining articles are classified according to the applications they focus on. Finally, we identify the potential research topics for fully integrated socially interactive neuromorphic robots

    Earthquake risk: Including Uncertainties in the Ground Motion Calculations

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    Earthquake risk models used by the insurance industry for estimating the damage caused by an event typically use the mean of the ground motion intensity to predict the damage to a particular building. On the other hand, the ground motion intensity can be modelled as a ran- dom variable. Literature related to ground-motion predictive equation derivation includes, as a rule, the estimate of the standard deviation associated with the distribution of the intensity. The Study Group was asked to find a way to include the uncertainty associated with the predic- tion of the ground motion intensity contained in the standard deviation into the damage calculation, in a way in which the computational effort is not increased significantly The Study Group proposed a way forward based on Bayes’ theorem for the marginal distribution of damage and found an analytical expression for the damage distribution function. However, the expression is an in- tegral that needs to be evaluated numerically and the Gaussian-Hermite quadrature was proposed to carry out the calculations. The approach seems plausible to be included in the existing models and the additional computational load is estimated as to be marginal relating to the current computational demands

    Predicting the distribution of canine leishmaniasis in western Europe based on environmental variables.

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    The domestic dog is the reservoir host of Leishmania infantum, the causative agent of zoonotic visceral leishmaniasis endemic in Mediterranean Europe. Targeted control requires predictive risk maps of canine leishmaniasis (CanL), which are now explored. We databased 2187 published and unpublished surveys of CanL in southern Europe. A total of 947 western surveys met inclusion criteria for analysis, including serological identification of infection (504, 369 dogs tested 1971-2006). Seroprevalence was 23 2% overall (median 10%). Logistic regression models within a GIS framework identified the main environmental predictors of CanL seroprevalence in Portugal, Spain, France and Italy, or in France alone. A 10-fold cross-validation approach determined model capacity to predict point-values of seroprevalence and the correct seroprevalence class (20%). Both the four-country and France-only models performed reasonably well for predicting correctly the 20% seroprevalence classes (AUC >0 70). However, the France-only model performed much better for France than the four-country model. The four-country model adequately predicted regions of CanL emergence in northern Italy (<5% seroprevalence). Both models poorly predicted intermediate point seroprevalences (5-20%) within regional foci, because surveys were biased towards known rural foci and Mediterranean bioclimates. Our recommendations for standardizing surveys would permit higher-resolution risk mapping
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