Search results for " Computer"

Dal formato cartaceo al formato digitale: uno studio qualitativo di test di matematica

Author Correction: Evaluation of three methods for biomass estimation in small invertebrates, using three large disparate parasite species as model o…

2018

Invertebrate biomass is considered one of the main factors driving processes in ecosystems. It can be measured directly, primarily by weighing individuals, but more often indirect estimators are used. We developed two indirect and non-destructive approaches to estimate biomass of small invertebrates in a simple manner. The first one was based on clay modelling and the second one was based on image analysis implemented with open-source software. Furthermore, we tested the accuracy of the widely used geometric approximation method (third method). We applied these three different methods to three morphologically disparate model species, an acanthocephalan worm, a crustacean and a flatworm. To …

CYGD: the Comprehensive Yeast Genome Database.

2005

The comprehensive resource is available under http://mips.gsf.de/genre/proj/yeast/.; International audience; The Comprehensive Yeast Genome Database (CYGD) compiles a comprehensive data resource for information on the cellular functions of the yeast Saccharomyces cerevisiae and related species, chosen as the best understood model organism for eukaryotes. The database serves as a common resource generated by a European consortium, going beyond the provision of sequence information and functional annotations on individual genes and proteins. In addition, it provides information on the physical and functional interactions among proteins as well as other genetic elements. These cellular network…

Reliable Outer Bounds for the Dual Simplex Algorithm with Interval Right-hand Side

2013

International audience; In this article, we describe the reliable computation of outer bounds for linear programming problems occuring in linear relaxations derived from the Bernstein polynomials. The computation uses interval arithmetic for the Gauss-Jordan pivot steps on a simplex tableau. The resulting errors are stored as interval right hand sides. Additionally, we show how to generate a start basis for the linear programs of this type. We give details of the implementation using OpenMP and comment on numerical experiments.

Designing a graphics processing unit accelerated petaflop capable lattice Boltzmann solver: Read aligned data layouts and asynchronous communication

2016

The lattice Boltzmann method is a well-established numerical approach for complex fluid flow simulations. Recently, general-purpose graphics processing units (GPUs) have become available as high-performance computing resources at large scale. We report on designing and implementing a lattice Boltzmann solver for multi-GPU systems that achieves 1.79 PFLOPS performance on 16,384 GPUs. To achieve this performance, we introduce a GPU compatible version of the so-called bundle data layout and eliminate the halo sites in order to improve data access alignment. Furthermore, we make use of the possibility to overlap data transfer between the host central processing unit and the device GPU with com…

Extraction d'un graphe de navigabilité à partir d'un nuage de points 3D enrichis

2017

International audience; Ce travail se place dans le cadre général du projet ANR pLaTINUM lié à la navigation autonome et plus parti-culièrement à la génération de cartes pour la navigation basée perception. Il consiste à développer une nouvelle méthode pour résumer une carte 3D (un nuage dense de points 3D) et extraire un graphe de navigabilité facilitant l'utilisation de cette carte par des systèmes de navigation à ressources matérielles limitées (smart-phones, voitures, robots.. .). Cette méthode vise à ex-traire les régions les plus saillantes de l'environnement étudié afin de construire une carte récapitulative. Ce processus de résumé de carte basé sur la vision est appliqué d'une façon…

Sélection de bandes pour la visualisation d'images spectrales : une approche basée sur l'étude de saillance

2011

National audience; De nos jours, la plupart des technologies d'affichage numériques sont basées sur le paradigme qu'une combinaison de trois couleurs primaires spécifiques est suffisante pour la reproduction d'une couleur quelconque pour l'oeil humain. Par ailleurs, les dispositifs d'affichage multispectraux ne sont pas encore monnaie courante sur le marché du multimédia. Ainsi, lorsqu'il s'agit de visualiser une image spectrale en couleur, sur un écran traditionnel, seuls trois bandes peuvent être utilisées simultanément, ce qui implique une réduction de dimensionnalité. Cette étape doit permettre la préservation d'un maximum de contenu informatif tout en préservant contrastes et couleurs …

Lidar detection of carbon dioxide in volcanic plumes

2015

Volcanic gases give information on magmatic processes. In particular, anomalous releases of carbon dioxide precede volcanic eruptions. Up to now, this gas has been measured in volcanic plumes with conventional measurements that imply the severe risks of local sampling and can last many hours. For these reasons and for the great advantages of laser sensing, the thorough development of volcanic lidar has been undertaken at the Diagnostics and Metrology Laboratory (UTAPRAD-DIM) of the Italian National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA). In fact, lidar profiling allows one to scan remotely volcanic plumes in a fast and continuous way, and with high s…

Ontology and protocol secure for SCADA

2014

In this work, we present a semantic cyber security system and we study its semantic intelligent systems vulnerabilities, focusing on the semantic attacks. For resolving semantic problems we propose a security global solution for the new generation of SCADA systems. The proposed solution aims at protecting critical semantic SCADA processes from the effects of major failures and semantic vulnerabilities in the modern IT-SCADA network. We used a security block in the global network access point, security protocols deployed in different network (OSI) levels and security ontologies deployed in security devices. We used our mixed coordinates (ECC) cryptography solution, this is an encryption tech…

Working the fields of big data : Using big-data-augmented online ethnography to study candidate–candidate interaction at election time

2017

The paper proposes big-data-augmented ethnography as a novel mixed-methods approach to studying political discussions in a hybrid media system. Using such empirical setup, the authors examined candidate–candidate online interaction during election campaigning. Candidate–candidate interaction crossing party boundaries is scarce and occurs in the form of negative campaigning via social media, with the shaming of rival candidates and engaging in battles with them. The authors posit that ethnographic observations can be used to contextualize the computational analysis of large data sets, while computational analysis can be applied to validate and generalize the findings made through ethnography…