1,608 research outputs found

    Introduction to Category Theory

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    A brief introduction to the general idea behind category theory with some basic definitions and examples. A perspective on higher dimensional categories is given

    Managing the Ethical Dimensions of Brain-Computer Interfaces in eHealth: An SDLC-based Approach

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    A growing range of brain-computer interface (BCI) technologies is being employed for purposes of therapy and human augmentation. While much thought has been given to the ethical implications of such technologies at the ‘macro’ level of social policy and ‘micro’ level of individual users, little attention has been given to the unique ethical issues that arise during the process of incorporating BCIs into eHealth ecosystems. In this text a conceptual framework is developed that enables the operators of eHealth ecosystems to manage the ethical components of such processes in a more comprehensive and systematic way than has previously been possible. The framework’s first axis defines five ethical dimensions that must be successfully addressed by eHealth ecosystems: 1) beneficence; 2) consent; 3) privacy; 4) equity; and 5) liability. The second axis describes five stages of the systems development life cycle (SDLC) process whereby new technology is incorporated into an eHealth ecosystem: 1) analysis and planning; 2) design, development, and acquisition; 3) integration and activation; 4) operation and maintenance; and 5) disposal. Known ethical issues relating to the deployment of BCIs are mapped onto this matrix in order to demonstrate how it can be employed by the managers of eHealth ecosystems as a tool for fulfilling ethical requirements established by regulatory standards or stakeholders’ expectations. Beyond its immediate application in the case of BCIs, we suggest that this framework may also be utilized beneficially when incorporating other innovative forms of information and communications technology (ICT) into eHealth ecosystems

    Impact of three ampicillin dosage regimens on selection of ampicillin resistance in Enterobacteriaceae and excretion of blaTEM genes in swine feces

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    The aim of this study was to assess the impact of three ampicillin dosage regimens on ampicillin resistance among Enterobacteriaceae recovered from swine feces using phenotypic and genotypic approaches. Phenotypically, ampicillin resistance was determined from the percentage of resistant Enterobacteriaceae and MICs of E. coli isolates. The pool of ampicillin resistance genes was also monitored by quantification of blaTEM genes, which code for the most frequently produced β-lactamases in Gram-negative bacteria, using a newly-developed real-time PCR assay. Ampicillin was administered intramuscularly and by oral route to fed or fasted pigs for 7 days at 20 mg/kg. The average percentage of resistant Enterobacteriaceae before treatment was between 2.5% and 12% and blaTEM genes quantities were below 107 copies/g of feces. By days four and seven, the percentage of resistant Enterobacteriaceae exceeded 50% in all treated groups, with some highly resistant strains (MIC>256µg/mL). In the control group, blaTEM genes quantities fluctuated between 104 - 106 copies/g of feces, whereas they fluctuated between 106-108 and 107-109 copies/g of feces for intramuscular and oral routes, respectively. Whereas phenotypic evaluations did not discriminate between the three ampicillin dosage regimens, blaTEM genes quantification was able to differentiate between the effects of two routes of ampicillin administration. Our results suggest that fecal blaTEM genes quantification provides a sensitive tool to evaluate the impact of ampicillin administration on the selection of ampicillin resistance in the digestive microflora and its dissemination in the environment

    A Cost-based Optimizer for Gradient Descent Optimization

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    As the use of machine learning (ML) permeates into diverse application domains, there is an urgent need to support a declarative framework for ML. Ideally, a user will specify an ML task in a high-level and easy-to-use language and the framework will invoke the appropriate algorithms and system configurations to execute it. An important observation towards designing such a framework is that many ML tasks can be expressed as mathematical optimization problems, which take a specific form. Furthermore, these optimization problems can be efficiently solved using variations of the gradient descent (GD) algorithm. Thus, to decouple a user specification of an ML task from its execution, a key component is a GD optimizer. We propose a cost-based GD optimizer that selects the best GD plan for a given ML task. To build our optimizer, we introduce a set of abstract operators for expressing GD algorithms and propose a novel approach to estimate the number of iterations a GD algorithm requires to converge. Extensive experiments on real and synthetic datasets show that our optimizer not only chooses the best GD plan but also allows for optimizations that achieve orders of magnitude performance speed-up.Comment: Accepted at SIGMOD 201

    Advanced Statistical Learning Theory

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    La modélisation d'accompagnement : une méthode de recherche participative et adaptative

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    Ce chapitre vise à présenter la diversité dans la mise en ½uvre d'un processus de modélisation d'accompagnement, mais aussi les points communs qui en émergent. L'objectif est de décrire pour mieux comprendre, sans intention normative. Nous nous appuyons sur l'analyse des cas d'études et des documents listés dans l'introduction. Notre analyse rassemble des cas concrets et des pratiques qui se réclament de la modélisation d'accompagnement et qui seront donc considérés comme tels dans notre analyse. La compatibilité de la diversité observée avec le cadre d'une adhésion aux principes initiaux de la charte sort du cadre de ce chapitre, elle est traitée dans la conclusion générale de l'ouvrage

    Joint Kernel Maps

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    We develop a methodology for solving high dimensional dependency estimation problems between pairs of data types, which is viable in the case where the output of interest has very high dimension, e.g. thousands of dimensions. This is achieved by mapping the objects into continuous or discrete spaces, using joint kernels. Known correlations between input and output can be defined by such kernels, some of which can maintain linearity in the outputs to provide simple (closed form) pre-images. We provide examples of such kernels and empirical results on mass spectrometry prediction and mapping between images

    Properties of rainfall in a tropical volcanic island deduced from UHF wind profiler measurements

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    The microphysical properties of rainfall at the island of Réunion are analysed and quantified according to one year of wind profiler observations collected at Saint-Denis international airport. The statistical analysis clearly shows important differences in rain vertical profiles as a function of the seasons. During the dry season, the vertical structure of precipitation is driven by trade wind and boundary-layer inversions, both of which limit the vertical extension of the clouds. The rain rate is lower than 2.5 mm h<sup>−1</sup> throughout the lower part of the troposphere (about 2 km) and decreases in the higher altitudes. During the moist season, the average rain rate is around 5 mm h<sup>−1</sup> and nearly uniform from the ground up to 4 km. <br><br> The dynamical and microphysical properties (including drop size distributions) of four distinct rainfall events are also investigated through the analysis of four case studies representative of the variety of rain events occurring on Réunion: summer deep convection, northerly-to-northeasterly flow atmospheric pattern, cold front and winter depression embedded in trade winds. Radar-derived rain parameters are in good agreement with those obtained from collocated rain gauge observations in all cases, which demonstrates that accurate qualitative and quantitative analysis can be inferred from wind profiler data. Fluxes of kinetic energy are also estimated from wind profiler observations in order to evaluate the impact of rainfall on soil erosion. Results show that horizontal kinetic energy fluxes are systematically one order of magnitude higher than vertical kinetic energy fluxes. A simple relationship between the reflectivity factor and vertical kinetic energy fluxes is proposed based on the results of the four case studies

    Statistical Learning Theory

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