Showing 77351–77364 of 78,293 results for "PensoAssathiany Dominique"

Book Series 2009 EN

Case Retrieval in Ontology-Based CBR Systems

Amjad Abou Assali · Dominique Lenné · Bruno Debray

International audienceThis paper presents our knowledge-intensive Case-Based Reasoning platform for diagnosis, COBRA. It integrates domain knowledge along with cases in an ontological structure. COBRA allows users to describe cases using any concept or instance of a domain ontology, which leads to a heterogeneous case base. Cases heterogeneity complicates their retrieval since correspondences must be identified between query and case attributes. We present in this paper our system architecture and the case retrieval phase. Then, we introduce the notions of similarity regions and attributes' roles used to overcome cases heterogeneity problems

Springer Science+Business Media
Book Series 2009 EN

Personalisation of Learning in Virtual Learning Environments

Dominique Verpoorten · Christian Glahn · Miloš Kravčík +2 more

Personalization of learning has become a prominent issue in the educational field, at various levels. This article elaborates a different view on personalisation than what usually occurs in this area. Its baseline is that personalisation occurs when learning turns out to become personal in the learner's mind. Through a literature survey, we analyze constitutive dimensions of this inner sense of personalisation. Here, we devote special attention to confronting learners with tracked information. Making their personal interaction footprints visible contrasts with the back-office usage of this data by researchers, instructors or adaptive systems. We contribute a prototype designed for the Moodle platform according to the conceptual approach presented here.

Springer Science+Business Media
Book Series 2009 EN

Improving Performance of ALM Systems with Bayesian Estimation of Peers Dynamics

Ihsan Ullah · Grégory Bonnet · Guillaume Doyen +1 more

P2P-based Application Layer Multicast (ALM) systems have shown a great success for several group communication applications. But some performance problems still await a major breakthrough from these systems for critical services such as live video streaming. For these applications, one of the problems is the dynamics of users' presence since the unannounced departure of a peer causes an interruption in service for all dependent ones. In this paper, we address this issue and propose a probabilistic approach based on Bayesian inference to anticipate users' departures and let peers react proactively. Through simulations and experimental evaluation, we prove that our approach improves significantly the performance of ALM systems with a low overhead.

Springer Science+Business Media
Book Series 2009 EN

Data Aggregation Scheme for a Multi-Application WSN

Ahmad Sardouk · Rana Rahim-Amoud · Leïla MerghemBoulahia +1 more

Wireless Sensor Networks (WSNs) are still designed and deployed for one specific application, while it is vital to deploy several applications over the same WSN in order to reduce the deployment and the administrative costs. One of the remaining problems, in this domain, resides in the data aggregation solutions, which are proposed generally for one application and may drain the WSN power in a multi-application context. Therefore, we propose a data aggregation scheme based on a multi-agent system to aggregate the WSN information in an energy-efficient manner even if we are deploying several applications over this network. This proposal has proved its performance in the context of one and several applications through successive simulations in different network scales.

Springer Science+Business Media
Book Series 2009 EN

Validating and Animating Higher-Order Recursive Functions in B

Michaël Leuschel · Dominique Cansell · Michael Butler

ProB is an animation and model checking tool for the B Method, which can deal with many interesting specifications. Some specifications, however, contain complicated functions which cannot be represented explicitly by a tool. We present a scheme with which higher-order recursive functions can be encoded in B, and establish soundness of this scheme. We then describe a symbolic representation for such functions. This representation enables ProB to successfully animate and model check a new class of relevant specifications, where animation is especially important due to the involved nature of the specification.

Springer Science+Business Media
Book Series 2009 EN

Universally Composable Quantum Multi-Party Computation

Dominique Unruh

The Universal Composability model (UC) by Canetti (FOCS 2001) allows forsecure composition of arbitrary protocols. We present a quantum version of theUC model which enjoys the same compositionality guarantees. We prove that inthis model statistically secure oblivious transfer protocols can be constructedfrom commitments. Furthermore, we show that every statistically classically UCsecure protocol is also statistically quantum UC secure. Such implications arenot known for other quantum security definitions. As a corollary, we get thatquantum UC secure protocols for general multi-party computation can beconstructed from commitments.

Springer Science+Business Media
Book Series 2009 EN

HST Observations of Gravitationally Lensed QSOs

Jean-François Claeskens · Dominique Sluse · Jean Surdej

Thanks to its sharp view, HST has significantly improved our knowledge of tens of gravitationally lensed quasars in four different respects: (1) confirming their lensed nature; (2) detecting the lensing galaxy responsible for the image splitting; (3) improving the astrometric accuracy on the positions of the unresolved QSO images and of the lens; (4) resolving extended lensed structures from the QSO hosts into faint NIR or optical rings or arcs. These observations have helped to break some degeneracies on the lens potential, to probe the galaxy evolution and to reconstruct the true shape of the QSO host with an increased angular resolution.

Springer International Publishing
Book Series 2009 EN

Stability and Computation of Medial Axes - a State-of-the-Art Report

Dominique Attali · JeanDaniel Boissonnat · Herbert Edelsbrunner

The medial axis of a geometric shape captures its connectivity. In spite of its inherent instability, it has found applications in a number of areas that deal with shapes. In this survey paper, we focus on results that shed light on this instability and use the new insights to generate simplified and stable modifications of the medial axis.

Springer Nature
Journals 2009 EN

Catestatin, an endogenous Chromogranin A-derived peptide, inhibits in vitro growth of Plasmodium falciparum

Aziza Akaddar · Cécile Doderer-Lang · Melissa R. Marzahn +8 more

Catestatin, an endogenous peptide derived from bovine chromogranin A, and its active domain cateslytin display powerful antimicrobial activities. We have tested the activities of catestatin and other related peptides on the growth of Plasmodium falciparum in vitro. Catestatin inhibits growth of the chloroquine-sensitive strain of P. falciparum 3D7, exhibiting 88% inhibition at 20 microM. A similar partial inhibition of parasite growth was observed for the chloroquine-resistant strain, 7G8 (64%,) and the multidrug-resistant strain, W2 (62%). In the presence of parasite-specific lactate dehydrogenase, a specific protein-protein interaction between catestatin and plasmepsin II precursor was demonstrated. In addition, catestatin partially inhibited the parasite-specific proteases plasmepsin in vitro. A specific interaction between catestatin and plasmepsins II and IV from P. falciparum and plasmepsin IV from the three remaining species of Plasmodium known to infect man was observed, suggesting a catestatin-induced reduction in availability of nutrients for protein synthesis in the parasite.

Springer Nature
Journals 2009 EN

Systemic properties of metabolic networks lead to an epistasis-based model for heterosis

Julie Fiévet · Christine Dillmann · Dominique de Vienne

The genetic and molecular approaches to heterosis usually do not rely on any model of the genotype-phenotype relationship. From the generalization of Kacser and Burns' biochemical model for dominance and epistasis to networks with several variable enzymes, we hypothesized that metabolic heterosis could be observed because the response of the flux towards enzyme activities and/or concentrations follows a multi-dimensional hyperbolic-like relationship. To corroborate this, we used the values of systemic parameters accounting for the kinetic behaviour of four enzymes of the upstream part of glycolysis, and simulated genetic variability by varying in silico enzyme concentrations. Then we "crossed" virtual parents to get 1,000 hybrids, and showed that best-parent heterosis was frequently observed. The decomposition of the flux value into genetic effects, with the help of a novel multilocus epistasis index, revealed that antagonistic additive-by-additive epistasis effects play the major role in this framework of the genotype-phenotype relationship. This result is consistent with various observations in quantitative and evolutionary genetics, and provides a model unifying the genetic effects underlying heterosis.

Springer Science+Business Media