10 research outputs found

    A review of existing evaluation methods for point clouds quality

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    This paper analyzes the existing evaluation methods for the point cloud quality and a new discussion regarding their applicability to aerial photographs is opened. Some of these methods are chosen based on practical issues and applied to a pair of reconstructions. The principal conclusion is that objective methods are the most interesting in photogrammetry applications, particularly the comparison between two point clouds.CONACYT – Consejo Nacional de Ciencia y TecnologíaPROCIENCI

    Cascade first and second order sliding mode controller of a quadrotor UAV based on exponential reaching law and modified super-twisting algorithm

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    Unmanned aerial vehicles have become a disruptive technology, which has experienced exponential growth in several applications. The control of these vehicles is a fairly wide area and the cascade PID controller is the most used in practice. However, this latter structure doesn’t ensure high performances in the presence of unmodelled dynamics, uncertainties and external abrupt disturbances. To that end, this work proposes a new method that consists of a non-linear cascade configuration of the variable structure control between first order sliding mode based on exponential reaching law and modified super-twisting second order sliding mode algorithm. The developed method is tested on simulation on a quadrotor system, the results obtained demonstrate good performance for trajectory tracking and as well as other non-linear controller options, it is robust against unmodeled dynamics and disturbances.CONACYT – Consejo Nacional de Ciencia y TecnologíaPROCIENCI

    Automatic scene reconstruction algorithm for planialtimetric applications

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    En este trabajo se implementa un algoritmo de reconstrucción de escenarios tridimensionales a partir de un par de imágenes aéreas. Para ello se supone que se posee una cámara calibrada, es decir, se conocen todos los parámetros internos de la cámara con la cual se obtuvieron las imágenes. El algoritmo propuesto se encarga de realizar el pareo de puntos homólogos, determinar la geometría del escenario y, finalmente, de realizar el computo de la nube de puntos correspondientes, para un par de imágenes cualesquiera.CONACYT – Consejo Nacional de Ciencia y TecnologíaPROCIENCI

    Clonal chromosomal mosaicism and loss of chromosome Y in elderly men increase vulnerability for SARS-CoV-2

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    The pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2, COVID-19) had an estimated overall case fatality ratio of 1.38% (pre-vaccination), being 53% higher in males and increasing exponentially with age. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, we found 133 cases (1.42%) with detectable clonal mosaicism for chromosome alterations (mCA) and 226 males (5.08%) with acquired loss of chromosome Y (LOY). Individuals with clonal mosaic events (mCA and/or LOY) showed a 54% increase in the risk of COVID-19 lethality. LOY is associated with transcriptomic biomarkers of immune dysfunction, pro-coagulation activity and cardiovascular risk. Interferon-induced genes involved in the initial immune response to SARS-CoV-2 are also down-regulated in LOY. Thus, mCA and LOY underlie at least part of the sex-biased severity and mortality of COVID-19 in aging patients. Given its potential therapeutic and prognostic relevance, evaluation of clonal mosaicism should be implemented as biomarker of COVID-19 severity in elderly people. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, individuals with clonal mosaic events (clonal mosaicism for chromosome alterations and/or loss of chromosome Y) showed an increased risk of COVID-19 lethality

    Operando two-terminal devices inside a transmission electron microscope

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    Abstract Advanced nanomaterials are at the core of innovation for the microelectronics industry. Designing, characterizing, and testing two-terminal devices, such as metal-insulator-metal structures, is key to improving material stack design and integration. Electrical biasing within in situ transmission electron microscopy using MEMS-based platforms is a promising technique for nano-characterization under operando conditions. However, conventional focused ion beam sample preparation can introduce parasitic current paths, limiting device performance and leading to overestimated electrical responses. Here we demonstrate connectivity of TEM lamella devices obtained from a novel electrical contacting method based solely on van der Waals forces. This method reduces parasitic leakage currents by at least five orders of magnitude relative to reported preparation approaches. Our methodology enables operation of stack devices inside a microscope with device currents as low as 10 pA. We apply this approach to observe in situ biasing-induced defect formation, providing valuable insights into the behavior of an SrTiO3-based memristor

    Child health in Latin America: historiographic perspectives and challenges

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    Deep Underground Neutrino Experiment (DUNE), Far Detector Technical Design Report, Volume I Introduction to DUNE

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    International audienceThe preponderance of matter over antimatter in the early universe, the dynamics of the supernovae that produced the heavy elements necessary for life, and whether protons eventually decay—these mysteries at the forefront of particle physics and astrophysics are key to understanding the early evolution of our universe, its current state, and its eventual fate. The Deep Underground Neutrino Experiment (DUNE) is an international world-class experiment dedicated to addressing these questions as it searches for leptonic charge-parity symmetry violation, stands ready to capture supernova neutrino bursts, and seeks to observe nucleon decay as a signature of a grand unified theory underlying the standard model. The DUNE far detector technical design report (TDR) describes the DUNE physics program and the technical designs of the single- and dual-phase DUNE liquid argon TPC far detector modules. This TDR is intended to justify the technical choices for the far detector that flow down from the high-level physics goals through requirements at all levels of the Project. Volume I contains an executive summary that introduces the DUNE science program, the far detector and the strategy for its modular designs, and the organization and management of the Project. The remainder of Volume I provides more detail on the science program that drives the choice of detector technologies and on the technologies themselves. It also introduces the designs for the DUNE near detector and the DUNE computing model, for which DUNE is planning design reports. Volume II of this TDR describes DUNE's physics program in detail. Volume III describes the technical coordination required for the far detector design, construction, installation, and integration, and its organizational structure. Volume IV describes the single-phase far detector technology. A planned Volume V will describe the dual-phase technology

    Deep Underground Neutrino Experiment (DUNE), Far Detector Technical Design Report, Volume II: DUNE Physics

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    The preponderance of matter over antimatter in the early universe, the dynamics of the supernovae that produced the heavy elements necessary for life, and whether protons eventually decay -- these mysteries at the forefront of particle physics and astrophysics are key to understanding the early evolution of our universe, its current state, and its eventual fate. DUNE is an international world-class experiment dedicated to addressing these questions as it searches for leptonic charge-parity symmetry violation, stands ready to capture supernova neutrino bursts, and seeks to observe nucleon decay as a signature of a grand unified theory underlying the standard model. The DUNE far detector technical design report (TDR) describes the DUNE physics program and the technical designs of the single- and dual-phase DUNE liquid argon TPC far detector modules. Volume II of this TDR, DUNE Physics, describes the array of identified scientific opportunities and key goals. Crucially, we also report our best current understanding of the capability of DUNE to realize these goals, along with the detailed arguments and investigations on which this understanding is based. This TDR volume documents the scientific basis underlying the conception and design of the LBNF/DUNE experimental configurations. As a result, the description of DUNE's experimental capabilities constitutes the bulk of the document. Key linkages between requirements for successful execution of the physics program and primary specifications of the experimental configurations are drawn and summarized. This document also serves a wider purpose as a statement on the scientific potential of DUNE as a central component within a global program of frontier theoretical and experimental particle physics research. Thus, the presentation also aims to serve as a resource for the particle physics community at large
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