Search results for "Simulation"
showing 10 items of 5095 documents
Qualifying semantic graphs using model checking
2011
International audience; Semantic interoperability problems have found their solutions using languages and techniques from the Semantic Web. The proliferation of ontologies and meta-information has improved the understanding of information and the relevance of search engine responses. However, the construction of semantic graphs is a source of numerous errors of interpretation or modeling and scalability remains a major problem. The processing of large semantic graphs is a limit to the use of semantics in current information systems. The work presented in this paper is part of a new research at the border of two areas: the semantic web and the model checking. This line of research concerns t…
A new approach based on NμSMV Model to query semantic graph
2011
International audience; The language most frequently used to represent the semantic graphs is the RDF (W3C standard for meta-modeling). The construction of semantic graphs is a source of numerous errors of interpretation. Processing of large semantic graphs can be a limit to use semantics in modern information systems. The work presented in this paper is part of a new research at the border between two areas: the semantic web and the model checking. For this, we developed a tool, RDF2NμSMV, which converts RDF graphs into NμSMV language. This conversion aims checking the semantic graphs with the model checker NμSMV in order to verify the consistency of the data. The data integration and shar…
Contrôle Optimal appliqué au contrôle de la phase en IRM : simulations et expériences sur fantômes
2017
National audience; IntroductionLes techniques IRM utilisant la phase du signal IRM, à la place ou en complément de l’amplitude, sont de plus en plus nombreuses. Dans ces techniques, la phase est gérée par l’application de gradients. Nous proposons ici de contrôler la phase du signal directement avec des impulsions RF. Pour cela, nous avons utilisé la théorie du contrôle optimal1 et calculé des impulsions RF optimisées pour atteindre des états cibles (dans notre cas, des motifs de phase) préalablement définis. Dans cette étude, une preuve de faisabilité de contrôle de la phase IRM par impulsions RF est présentée au travers de simulations (avec le logiciel ODIN2) ainsi que d’expériences IRM s…
WSN localization scheme based on Received Signal Strength Indicator (RSSI) for ZigBee Networks
2015
International audience; Wireless Sensor Networks (WSNs) have diverse application domains such as smart home, smart care, industrial, etc. We present a WSN system based on the ZigBee technology (IEEE 802.15.4) in Smart Home. In our paper we interest to ZigBee protocol is often used in medical Rehabilitation, which is a relatively new concept involving wireless transmission of data from the sensors attached to a patient to a distant monitoring station. There is no standardized topology managing the current networks, therefore, we will compare and evaluate the performance the mobility of nodes for star topologies in different scenarios to determine which is the most suitable in a typical hospi…
Couplage visuo-haptique en environnement de conduite simulée
2012
Our visual-haptic system is requested as soon as our arms interact with our external environment. There is a coupling between visual and haptic modalities, so that the central nervous system takes in account the reliability and accuracy of both modalities in order to weigh their influence in the visual-haptic integration. Thus there is a rebalancing of the weight of each modality in the context of the visual-haptic solicitation. Typically, psychophysical studies implement short and repeated tasks, with or without sensory conflict, to understand the mechanisms underlying the visual-haptic coupling. Applied in our context, this method is excluded because we have to maintain the ecological cha…
Approche coopérative pour l'acquisition et l'observation de formes tridimensionnelles
2009
Technologic progres can reduce the barrier between real image and virtual image so far it is really difficult to recognize them. When virtual reality is well done, augmented reality, from virtual world to real world, is still developped. We want to project a virtual texture onto a 3D real object. By using cameras and projector, we estimate its real pose in the virtual reference by projecting a coded pattern to find points of correspondence between cameras and projector onto the textureless object, where common detector of points of correspondence are useless. We combine the calibration of the system and these points to estimate the 3D position of the object, and then register with a fine mo…
Fractional half-tangent of a curve described by Iterated Function Systems.
2009
International audience; The deterministic fractal curves and surfaces find many applications in modeling of rough objects. However, these curves and surfaces are nowhere differentiable. Without notion of tangent, we can not determine the relative orientation of two fractal shapes, to join them with a "natural" aspect. Various works proposed a generalization of the concept of derivative by introducing the fractional derivative. In this paper we apply this concept of fractional derivative to the curves described by Iterated Function Systems. We show that if the fractional derivative exists at boundary points of the curve, the direction of the fractional half-tangent is necessarily the eigenve…
Tangentes à une courbe fractale
2007
http://www.irit.fr/REFIG/index.php/refig/article/view/10; National audience; Nous nous intéressons au calcul des tangentes à une courbe fractale définie à l'aide d'un IFS. Généralement, les courbes fractales sont nulle part dérivables, mais sous certaines conditions on peut montrer qu'elles admettent, en un ensemble de points, des demi-tangentes à droite et à gauche. Nous proposons une méthode permettant de déterminer ces demi-tangentes.
The Hierarchical Agglomerative Clustering with Gower index: a methodology for automatic design of OLAP cube in ecological data processing context
2015
In Press, Corrected Proof; International audience; The OLAP systems can be an improvement for ecological studies. In fact, ecology studies, follows and analyzes phenomenon across space and time and according to several parameters. OLAP systems can provide to ecologists browsing in a large dataset. One focus of the current research on OLAP system is the automatic design of OLAP cubes and of data warehouse schemas. This kind of works makes accessible OLAP technology to non information technology experts. But to be efficient, the automatic OLAP building must take into account various cases. Moreover the OLAP technology is based on the concept of hierarchy. Thereby the hierarchical clustering m…
OPTIMIZATIONS FOR TENSORIAL BERNSTEIN–BASED SOLVERS BY USING POLYHEDRAL BOUNDS
2010
The tensorial Bernstein basis for multivariate polynomials in n variables has a number 3n of functions for degree 2. Consequently, computing the representation of a multivariate polynomial in the tensorial Bernstein basis is an exponential time algorithm, which makes tensorial Bernstein-based solvers impractical for systems with more than n = 6 or 7 variables. This article describes a polytope (Bernstein polytope) with a number of faces, which allows to bound a sparse, multivariate polynomial expressed in the canonical basis by solving several linear programming problems. We compare the performance of a subdivision solver using domain reductions by linear programming with a solver using a c…