880 research outputs found

    Conceptos Plasticos

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    https://openscholarship.wustl.edu/bcs/1486/thumbnail.jp

    Financial Crisis, Health Outcomes and Aging: Mexico in the 1980s and 1990s

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    We study the impact of economic crisis on health in Mexico. There have been four wide-scale economic crises in Mexico in the past two decades, the most recent in 1995-96. We find that mortality rates for the very young and the elderly increase or decline less rapidly in crisis years as compared with non-crisis years. In late 1995-96 crisis, mortality rates were about 5 to 7 percent higher in the crisis years compared to the years just prior to the crisis. This translates into a 0.4 percent increase in mortality for the elderly and a 0.06 percent increase in mortality for the very young. We find tentative evidence that economic crises affect mortality by reducing incomes and possibly by placing a greater burden on the medical sector, but not by forcing less healthy members of the population to work or by forcing primary caregivers to go to work.

    AFT-VO: Asynchronous Fusion Transformers for Multi-View Visual Odometry Estimation

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    Motion estimation approaches typically employ sensor fusion techniques, such as the Kalman Filter, to handle individual sensor failures. More recently, deep learning-based fusion approaches have been proposed, increasing the performance and requiring less model-specific implementations. However, current deep fusion approaches often assume that sensors are synchronised, which is not always practical, especially for low-cost hardware. To address this limitation, in this work, we propose AFT-VO, a novel transformer-based sensor fusion architecture to estimate VO from multiple sensors. Our framework combines predictions from asynchronous multi-view cameras and accounts for the time discrepancies of measurements coming from different sources. Our approach first employs a Mixture Density Network (MDN) to estimate the probability distributions of the 6-DoF poses for every camera in the system. Then a novel transformer-based fusion module, AFT-VO, is introduced, which combines these asynchronous pose estimations, along with their confidences. More specifically, we introduce Discretiser and Source Encoding techniques which enable the fusion of multi-source asynchronous signals. We evaluate our approach on the popular nuScenes and KITTI datasets. Our experiments demonstrate that multi-view fusion for VO estimation provides robust and accurate trajectories, outperforming the state of the art in both challenging weather and lighting conditions

    Generalizing to New Tasks via One-Shot Compositional Subgoals

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    The ability to generalize to previously unseen tasks with little to no supervision is a key challenge in modern machine learning research. It is also a cornerstone of a future "General AI". Any artificially intelligent agent deployed in a real world application, must adapt on the fly to unknown environments. Researchers often rely on reinforcement and imitation learning to provide online adaptation to new tasks, through trial and error learning. However, this can be challenging for complex tasks which require many timesteps or large numbers of subtasks to complete. These "long horizon" tasks suffer from sample inefficiency and can require extremely long training times before the agent can learn to perform the necessary longterm planning. In this work, we introduce CASE which attempts to address these issues by training an Imitation Learning agent using adaptive "near future" subgoals. These subgoals are recalculated at each step using compositional arithmetic in a learned latent representation space. In addition to improving learning efficiency for standard long-term tasks, this approach also makes it possible to perform one-shot generalization to previously unseen tasks, given only a single reference trajectory for the task in a different environment. Our experiments show that the proposed approach consistently outperforms the previous state-of-the-art compositional Imitation Learning approach by 30%.Comment: Present at ICRA 2022 "Compositional Robotics: Mathematics and Tools

    MDN-VO: Estimating Visual Odometry with Confidence

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    Visual Odometry (VO) is used in many applications including robotics and autonomous systems. However, traditional approaches based on feature matching are computationally expensive and do not directly address failure cases, instead relying on heuristic methods to detect failure. In this work, we propose a deep learning-based VO model to efficiently estimate 6-DoF poses, as well as a confidence model for these estimates. We utilise a CNN - RNN hybrid model to learn feature representations from image sequences. We then employ a Mixture Density Network (MDN) which estimates camera motion as a mixture of Gaussians, based on the extracted spatio-temporal representations. Our model uses pose labels as a source of supervision, but derives uncertainties in an unsupervised manner. We evaluate the proposed model on the KITTI and nuScenes datasets and report extensive quantitative and qualitative results to analyse the performance of both pose and uncertainty estimation. Our experiments show that the proposed model exceeds state-of-the-art performance in addition to detecting failure cases using the predicted pose uncertainty

    Rule of law versus soft rule of law

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    The power of the government rather than limiting it), human rights and democracy. Therefore, this paper will explore the following research questions: 1. Is the current macro legal framework in Peru and Ecuador consistent with what is generally defined as Rule of Law or is it more related to what is known as Soft Rule of Law? 2. To what extend does a theoretical analysis support the prevailing of a Soft Rule of Law in Ecuador and Peru? This paper has been divided into seven sections. Section one refers to a theoretical revision of the term Rule of Law, section two presents on the concept of soft rule of law, section three focuses on human rights as an essential element of the Rule of Law, section four explores the interaction between democracy and the Rule of Law, section five refers to the challenges faced by the Rule of Law in a consolidated democracy, section six presents, as an example, a brief reflection on the current problems of Peru and Ecuador and finally the paper’s conclusions are submitted.Campus Lima Centr

    Rigorous diffraction of an electromagnetic beam by wavelength-size slits

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    A rigorous modal theory for the diffraction of Gaussian beams from N slits in an otherwise perfectly plane conducting screen (line finite-grating) is presented. The case of normal incidence and T.E.-polarization is considered, i.e. the electric field is parallel to the strips. The characteristics of the far-field radiation pattern as a function of the wavelength are analyzed, particularly within the vectorial region where the influence of polarization is more important. Furthermore, the influence of the beam width and beam alignment on the transmission coefficient, on the normally diffracted energy, and on the diffraction is studied

    Teoría rigurosa de la dispersión de haces gaussianos por una rejilla con sustrato metálico

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    Se presenta una teoría rigurosa de la dispersión de haces Gaussianos a incidencia normal y oblicua por una rejilla finita en una pantalla conductora, de espesor cero y con sustrato metálico. El sustrato puede ser el vacío o un conductor. Se considera el caso de polarización T.E., es decir, el campo eléctrico es paralelo a las rendijas. Se analiza en la región vectorial de la difracción a patrones de dispersión en función de la longitud de onda, del hacho del haz y de la posición del haz. De estos resultados se ha encontrado que el ancho de los órdenes de dispersión aumenta con la relación λ/L, donde λ es la longitud de onda y L el ancho del haz incidente. Cuando el sustrato es un conductor la ecuación de dispersión por una rejilla en reflexión predice la posición angular de los órdenes dispersados de una rejilla finita con una buena aproximación. Además, la posición angular de estos órdenes es independiente del sustrato, del ancho y de la posición del haz

    Late Palaeozoic lithostratigraphy of the Andean Precordillera revisited (San Juan Province, Argentina)

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    New data on some neopalaeozoic lithostratigraphic units of the central sector of the Argentinean Precordillera are presented. The western Precordillera displays occasional outcrops of siliciclastic rocks of the Late Palaeozoic. These rocks are separated by two main unconformi­ties related to the development of the Chanic (Upper Devonian-early Carboniferous) and Gondwanan (late Carboniferous-early Permian) orogens. A major unconformity marks the beginning of the Andean cycle in middle Permian times. The Del Ratón Formation (800 m) in the studied area is made up of conglomerates and can be divided into two units. The basal part (Lower Member) was deposited in a fjord environment. The Upper Member was generated by an alluvial system that was mainly dominated by upper flow-regime plane beds, whereas its uppermost part accumulated in a fan delta setting. The clast provenance and the main palaeocurrents suggest the existence of a significant topographic high to the W and NW of the present outcrops. The El Planchón Formation (1400 m) is mainly composed of shales and sandstones as a result of sedimentation in a deep-sea fan environment. These lutite-dominated materials graded laterally north­wards into conglomerates in a glacial setting. The Del Ratón and El Planchón formations of the Lower Carboniferous correspond to the synorogenic Chanic sedimentation (Chanic foreland basin). Thereafter, the stratigraphic succession underwent deformation which led to its prolonged subaerial exposure and rubefaction. In Permian times, a marine transgression gave rise to the Del Salto Formation (600 m), which is constituted by beach deposits with some aeolian reworking and which lies unconformably over the Lower Carboniferous rocks. Conglomerates (Quebrada del Alumbre Formation, 100 m) produced by an alluvial system prograded episodically into coastal areas. The Escombrera Formation (350 m) is composed of beach deposits prograding seawards. This formation probably represents the end of the Palaeozoic sedimentary record. Thereafter, a playa-lake and an alluvial fan system were generated (Quebrada de la Arena Formation). This unit (750 m) was the last infill of the Gondwanan retroarc foreland, the total thickness of which was about 4000 m.Se presentan nuevos datos sobre las unidades neopaleozoicas aflorantes en la parte occidental de la Precordillera andina. Esas unidades litoestratigráficas estan separadas por dos discordancias angulares principales asociadas al desarrollo de las orogenias Chánica (Devónico tardío-Carbonífero temprano) y Gondwánica (Carbonífero tardío-Pérmico temprano) respectivamente. Otra nueva discordancia sugiere el inicio del ciclo andino durante el Pérmico medio. La Formación Del Ratón (800 m) está constituida principalmente por conglomerados y puede dividirse en dos unidades de rango menor: la parte basal y la parte superior respectivamente. La parte basal (Miembro inferior) fue acumulada en un fiordo. La parte superior (Miembro superior) fue generada en un sistema alluvial dominado predominantemente por la acumulación de capas planas de alto régimen de flujo, mientras que la parte más alta fue depositada en un entorno de abanico deltaico (fandelta). La procedencia de los clastos y las paleocorrientes principales indican la presencia de un relieve topográfico alto y significativo, situado al O y NO de los afloramientos actuales.La Formación El Planchón (1400 m) constituida principalmente por lutitas y areniscas fue acumulada en un contexto de abanico submarino (deep-sea fan). Estos materiales predominantemente lutíticos pasan lateralmente hacia el norte a conglomerados acumulados en un ambiente sedimentario glacial. Las Formaciones Del Ratón y El Planchón corresponden a la sedimentación sinorogénica Chánica (cuenca de antepaís chánica). Posteriormente, la sucesión estratigráfica sufrió una deformación que dió lugar a una prolongada exposición subaérea y su consiguiente rubefacción. Durante el Pérmico, una transgresión marina produjo la acumulación de la Formación Del Salto (600 m), que está constituída por depósitos de playa con algún retrabajamiento eólico y que recubre discordantemente los materiales del Carbonífero inferior. Un sistema aluvial conglomerático (Formación Quebrada del Alumbre 100 m) pogradó episódicamente sobre las zonas costeras. La Formación Escombrera (350 m), que está constituída por materiales arenosos coste-ros progradantes hacia el mar, representa, muy probablemente, el final del registro sedimentario paleozoico en esta zona. Posteriormente se generó otra discordancia sobre la que se acumularon materiales arenosos en un contexto de cursos fluviales trenzados sobre los que se disponen materiales lutíticos acumulados en una ciénaga (playa-lake) que gradan, primero a cursos trenzados, luego a cursos sinousos y finalmente a abanicos aluviales (Formación Quebrada de la Arena). Esta unidad (750 m) corresponde al último relleno sedimentario de la cuenca Gondwánica de retroarco, cuya potencia es del orden de unos 4000 m.Fil: Colombo, F.. Universidad de Barcelona; EspañaFil: Limarino, Carlos Oscar. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Geología; ArgentinaFil: Spalletti, Luis Antonio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigaciones Geológicas. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Centro de Investigaciones Geológicas; ArgentinaFil: Busquets, P. Universidad de Barcelona; EspañaFil: Cardo, R.. Secretaría de Industria y Minería. Servicio Geológico Minero Argentino; ArgentinaFil: Mendez Bedia, I. Universidad de Oviedo; EspañaFil: Heredia, N.. Instituto Geológico y Minero de España; Españ

    There and Back Again: Self-supervised Multispectral Correspondence Estimation

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    Across a wide range of applications, from autonomous vehicles to medical imaging, multi-spectral images provide an opportunity to extract additional information not present in color images. One of the most important steps in making this information readily available is the accurate estimation of dense correspondences between different spectra. Due to the nature of cross-spectral images, most correspondence solving techniques for the visual domain are simply not applicable. Furthermore, most cross-spectral techniques utilize spectra-specific characteristics to perform the alignment. In this work, we aim to address the dense correspondence estimation problem in a way that generalizes to more than one spectrum. We do this by introducing a novel cycle-consistency metric that allows us to self-supervise. This, combined with our spectra-agnostic loss functions, allows us to train the same network across multiple spectra. We demonstrate our approach on the challenging task of dense RGB-FIR correspondence estimation. We also show the performance of our unmodified network on the cases of RGB-NIR and RGB-RGB, where we achieve higher accuracy than similar self-supervised approaches. Our work shows that cross-spectral correspondence estimation can be solved in a common framework that learns to generalize alignment across spectra
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