Measure of combined effects of morphological parameters of inclusions within composite materials via stochastic homogenization to determine effective mechanical properties

In our previous papers we have described efficient and reliable methods of generation of representative volume elements (RVE) perfectly suitable for analysis of composite materials via stochastic homogenization. In this paper we profit from these methods to analyze the influence of the morphology on the effective mechanical properties of the samples. More precisely, we study the dependence of main mechanical characteristics of a composite medium on various parameters of the mixture of inclusions composed of spheres and cylinders. On top of that we introduce various imperfections to inclusions and observe the evolution of effective properties related to that. The main computational approach used throughout the work is the FFT-based homogenization technique, validated however by comparison with the direct finite elements method. We give details on the features of the method and the validation campaign as well. Keywords: Composite materials, Cylindrical and spherical reinforcements, Mechanical properties, Stochastic homogenization.Comment: 23 pages, updated figures, version accepted to Composite Structures 201

Dogs with hearing and/or visual impairment are as capable as any dogs to communicate and cooperate with humans.

International audienc

Multiple Comparative Metagenomics using Multiset k-mer Counting

Background. Large scale metagenomic projects aim to extract biodiversity knowledge between different environmental conditions. Current methods for comparing microbial communities face important limitations. Those based on taxonomical or functional assignation rely on a small subset of the sequences that can be associated to known organisms. On the other hand, de novo methods, that compare the whole sets of sequences, either do not scale up on ambitious metagenomic projects or do not provide precise and exhaustive results. Methods. These limitations motivated the development of a new de novo metagenomic comparative method, called Simka. This method computes a large collection of standard ecological distances by replacing species counts by k-mer counts. Simka scales-up today's metagenomic projects thanks to a new parallel k-mer counting strategy on multiple datasets. Results. Experiments on public Human Microbiome Project datasets demonstrate that Simka captures the essential underlying biological structure. Simka was able to compute in a few hours both qualitative and quantitative ecological distances on hundreds of metagenomic samples (690 samples, 32 billions of reads). We also demonstrate that analyzing metagenomes at the k-mer level is highly correlated with extremely precise de novo comparison techniques which rely on all-versus-all sequences alignment strategy or which are based on taxonomic profiling

Génération aléatoire de VER à inclusions géométriques modulables inspirée de la dynamique moléculaire

Les matériaux composites sont de plus en plus élaborés pour répondre à des demandes plus exigeantes dans l'industrie aéronautique, automobile,.... L'objectif d'un nouveau matériau est de garantir des caractéristiques supérieures à celles des matériaux déjà existants, selon l'usage qu'on lui destine. Ils sont complexes dans leur mise en ?uvre et leur expérimentation est souvent délicate et onéreuse. Pour étudier un matériau en phase de conception, nous pouvons nous intéresser à ses caractéristiques homogénéisées mécaniques et thermiques. Pour ce faire, nous recourons à des méthodes expérimentales ou bien numériques avec l'utilisation des éléments finis ou de la FFT (Fast Fourier Transform). Dans une simulation numérique en 3D, nous devons disposer d'une représentation en 3D du matériau (maillage ou images). Des images peuvent être obtenues par tomographie, mais cette technique est coûteuse, demande d'avoir accès à des appareils peu accessibles au niveau académique et nécessite un traitement d'image. C'est pourquoi, naturellement, la génération aléatoire permet de répondre à cette problématique. Plus particulièrement, nous nous intéressons à la génération aléatoire d'un matériau composite en 3D de type matrice renforcée. Dans la littérature, nous trouvons la méthode RSA très efficace pour des volumes d'inclusions allant jusqu'à 30 % environ. Toutefois, pour des volumes supérieurs d'inclusions, la méthode RSA devient prohibitive en temps. Nous proposons alors de générer des VER 3D de type matrice renforcée d'inclusions à géométrie sphérique, cylindrique ou elliptique en utilisant une méthode inspirée de la dynamique moléculaire. Cette génération aléatoire garantit des inclusions disjointes deux à deux, pouvant au besoin être déformées, arrachées partiellement, ou pelliculées. L'intérêt de la génération proposée est sa capacité à générer aléatoirement sans recouvrement un VER avec des taux d'inclusions supérieurs à 30 % du volume total. Le taux d'inclusion (à dimensions constantes pour chaque type d'inclusion) peut en effet atteindre 60 % du volume total. De plus, cette méthode basée sur la dynamique moléculaire est capable de générer des VER à des taux d'inclusions supérieurs à 60 % en prenant en compte des tailles variables des géométries choisies pour les inclusions, typiquement cela consiste à faire varier le rayon des sphères et / ou des cylindres et / ou des sphéroïdes. La génération prend alors en compte un grand nombre d'inclusions (de l'ordre de 1000 ou davantage). Les applications de cette génération sont multiples. Elle est modulable : les géométries considérées sont diverses, les inclusions peuvent être post-traitées pour être pelliculées ou déformées. Elle s'adapte aux calculs de coefficients homogénéisés en élasticité et en thermique via des méthodes de type éléments finis ou des méthodes basées sur la FFT (Fast Fourier Transform)

Combination of deep neural networks and logical rules for record segmentation in historical handwritten registers using few examples

International audienceThis work focuses on the layout analysis of historical handwritten registers, in which local religious ceremonies were recorded. The aim of this work is to delimit each record in these registers. To this end, two approaches are proposed. Firstly, object detection networks are explored, as three state-of-the-art architectures are compared. Further experiments are then conducted on Mask R-CNN, as it yields the best performance. Secondly, we introduce and investigate Deep Syntax, a hybrid system that takes advantages of recurrent patterns to delimit each record, by combining ushaped networks and logical rules. Finally, these two approaches are evaluated on 3708 French records (16-18th centuries), as well as on the Esposalles public database, containing 253 Spanish records (17th century). While both systems perform well on homogeneous documents, we observe a significant drop in performance with Mask R-CNN on heterogeneous documents, especially when trained on a non-representative subset. By contrast, Deep Syntax relies on steady patterns, and is therefore able to process a wider range of documents with less training data. Not only Deep Syntax produces 15% more match configurations and reduces the ZoneMap surface error metric by 30% when both systems are trained on 120 images, but it also outperforms Mask R-CNN when trained on a database three times smaller. As Deep Syntax generalizes better, we believe it can be used in the context of massive document processing, as collecting and annotating a sufficiently large and representative set of training data is not always achievable

Computation of thermal properties via 3D homogenization of multiphase materials using FFT-based accelerated scheme

In this paper we study the thermal effective behaviour for 3D multiphase composite material consisting of three isotropic phases which are the matrix, the inclusions and the coating media. For this purpose we use an accelerated FFT-based scheme initially proposed in Eyre and Milton (1999) to evaluate the thermal conductivity tensor. Matrix and spherical inclusions media are polymers with similar properties whereas the coating medium is metallic hence better conducting. Thus, the contrast between the coating and the others media is very large. For our study, we use RVEs (Representative volume elements) generated by RSA (Random Sequential Adsorption) method developed in our previous works, then, we compute effective thermal properties using an FFT-based homogenization technique validated by comparison with the direct finite elements method. We study the thermal behaviour of the 3Dmultiphase composite material and we show what features should be taken into account to make the computational approach efficient

Next-Generation EU DataGrid Data Management Services

We describe the architecture and initial implementation of the next-generation of Grid Data Management Middleware in the EU DataGrid (EDG) project. The new architecture stems out of our experience and the users requirements gathered during the two years of running our initial set of Grid Data Management Services. All of our new services are based on the Web Service technology paradigm, very much in line with the emerging Open Grid Services Architecture (OGSA). We have modularized our components and invested a great amount of effort towards a secure, extensible and robust service, starting from the design but also using a streamlined build and testing framework. Our service components are: Replica Location Service, Replica Metadata Service, Replica Optimization Service, Replica Subscription and high-level replica management. The service security infrastructure is fully GSI-enabled, hence compatible with the existing Globus Toolkit 2-based services; moreover, it allows for fine-grained authorization mechanisms that can be adjusted depending on the service semantics.Comment: Talk from the 2003 Computing in High Energy and Nuclear Physics (CHEP03), La Jolla,Ca, USA, March 2003 8 pages, LaTeX, the file contains all LaTeX sources - figures are in the directory "figures

Lack of phenotypic and evolutionary cross-resistance against parasitoids and pathogens in Drosophila melanogaster

BackgroundWhen organisms are attacked by multiple natural enemies, the evolution of a resistance mechanism to one natural enemy will be influenced by the degree of cross-resistance to another natural enemy. Cross-resistance can be positive, when a resistance mechanism against one natural enemy also offers resistance to another; or negative, in the form of a trade-off, when an increase in resistance against one natural enemy results in a decrease in resistance against another. Using Drosophila melanogaster, an important model system for the evolution of invertebrate immunity, we test for the existence of cross-resistance against parasites and pathogens, at both a phenotypic and evolutionary level.MethodsWe used a field strain of D. melanogaster to test whether surviving parasitism by the parasitoid Asobara tabida has an effect on the resistance against Beauveria bassiana, an entomopathogenic fungus; and whether infection with the microsporidian Tubulinosema kingi has an effect on the resistance against A. tabida. We used lines selected for increased resistance to A. tabida to test whether increased parasitoid resistance has an effect on resistance against B. bassiana and T. kingi. We used lines selected for increased tolerance against B. bassiana to test whether increased fungal resistance has an effect on resistance against A. tabida.Results/ConclusionsWe found no positive cross-resistance or trade-offs in the resistance to parasites and pathogens. This is an important finding, given the use of D. melanogaster as a model system for the evolution of invertebrate immunity. The lack of any cross-resistance to parasites and pathogens, at both the phenotypic and the evolutionary level, suggests that evolution of resistance against one class of natural enemies is largely independent of evolution of resistance against the other

Storage Resource Manager version 2.2: design, implementation, and testing experience

Storage Services are crucial components of the Worldwide LHC Computing Grid Infrastructure spanning more than 200 sites and serving computing and storage resources to the High Energy Physics LHC communities. Up to tens of Petabytes of data are collected every year by the four LHC experiments at CERN. To process these large data volumes it is important to establish a protocol and a very efficient interface to the various storage solutions adopted by the WLCG sites. In this work we report on the experience acquired during the definition of the Storage Resource Manager v2.2 protocol. In particular, we focus on the study performed to enhance the interface and make it suitable for use by the WLCG communities. At the moment 5 different storage solutions implement the SRM v2.2 interface: BeStMan (LBNL), CASTOR (CERN and RAL), dCache (DESY and FNAL), DPM (CERN), and StoRM (INFN and ICTP). After a detailed inside review of the protocol, various test suites have been written identifying the most effective set of tests: the S2 test suite from CERN and the SRM-Tester test suite from LBNL. Such test suites have helped verifying the consistency and coherence of the proposed protocol and validating existing implementations. We conclude our work describing the results achieved