HAL-Univ-Nantes

    Using Event-B to Verify the Kmelia Components and Their Assemblies

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    International audienceBuilding reliable software systems from components requires to verify the consistency of components and the correctness of component assemblies. In this work, we design a verification method to address the problem of verifying the consistency of components states and the correctness of assembly contracts, using pre-/post-conditions. The starting point is specifications written with the Kmelia component model: a Kmelia component type declares provided and required services which are used to link components in component assemblies. We generate Event-B models from Kmelia specifications in such a way that we can check the consistency and also the correctness of assembly at the Kmelia level, using Event-B provers. An illustrative example based on a stock management system is used to support the presentation

    Field return on a Chinese-French double graduation of an International Master in Microelectronics on the Base of the Bologna Process

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    International audienceWith the decrease in France of the number of students in the field of electrical engineering and information processing, that is unfortunately more and more common in Europe, several French Institutions are trying to build remote formations in Asia-Pacific region. This paper deals with the setup of a new master degree in the field of electrical and information engineering with two specialties, microelectronics and signal and image processing. It is a double diploma between South-East University (SEU) at Nanjing (China) and the University of Rennes 1, at Rennes (France), fully compatible with the Bologna process rules more especially in terms of ECTS. In this paper, some details on the structure and on the specific points that were solved are described and commented. In particular, the pedagogical program was built on the bases of the reciprocal competencies in order to take at the maximum the benefit of skills available on each side

    Inverse scattering at fixed energy in de Sitter-Reissner-Nordström black holes

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    40 pagesIn this paper, we consider massless Dirac fields propagating in the outer region of de Sitter-Reissner-Nordström black holes. We show that the metric of such black holes is uniquely determined by the partial knowledge of the corresponding scattering matrix S(λ)S(\lambda) at a fixed energy λ0\lambda \ne 0. More precisely, we consider the partial wave scattering matrices S(λ,n)S(\lambda,n) (here λ0\lambda \ne 0 is the fixed energy and nNn \in \N^* denotes the angular momentum) defined as the restrictions of the full scattering matrix on a well chosen basis of spin-weighted spherical harmonics. We prove that the mass MM, the square of the charge Q2Q^2 and the cosmological constant Λ\Lambda of a dS-RN black hole (and thus its metric) can be uniquely determined from the knowledge of either the transmission coefficients T(λ,n)T(\lambda, n), or the reflexion coefficients R(λ,n)R(\lambda, n) (resp. L(λ,n)L(\lambda, n)), for all nLn \in {\mathcal{L}} where L\mathcal{L} is a subset of N\N^* that satisfies the Müntz condition nL1n=+\sum_{n \in {\mathcal{L}}} \frac{1}{n} = +\infty. Our main tool consists in complexifying the angular momentum nn and in studying the analytic properties of the "unphysical" scattering matrix S(λ,z)S(\lambda,z) in the complex variable zz. We show in particular that the quantities 1T(λ,z)\frac{1}{T(\lambda,z)}, R(λ,z)T(λ,z)\frac{R(\lambda,z)}{T(\lambda,z)} and L(λ,z)T(λ,z)\frac{L(\lambda,z)}{T(\lambda,z)} belong to the Nevanlinna class in the region \{z \in \C, \ Re(z) >0 \} for which we have analytic uniqueness theorems at our disposal. Eventually, as a by-product of our method, we obtain reconstrution formulae for the surface gravities of the event and cosmological horizons of the black hole which have an important physical meaning in the Hawking effect

    Fusion de résultats en recherche d'information : application aux documents manuscrits en-ligne

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    Ce travail présente les résultats d'une étude sur la combinaison des deux approches majeures existantes pour la recherche de documents manuscrits en-ligne. La première approche consiste à appliquer des méthodes de recherche d'information (RI) aux documents issus d'un processus de reconnaissance. La deuxième, quant à elle, ne nécessite pas de reconnaissance explicite et utilise un algorithme de word spotting. La fusion permet d'améliorer les performances de la recherche. Les résultats montrent que pour des textes ayant un taux d'erreur au niveau mot inférieur à 23 %, les performances après fusion sont comparables à celles obtenues avec la vérité terrain. De plus, pour des textes fortement dégradés, des améliorations sont également observées

    Towards a Simplified Perceptual Quality Metric for Watermarking Applications

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    International audienceThis work is motivated by the limitations of statistical quality metrics to assess the quality of images distorted in distinct frequency range. Common quality metrics, which basically have been designed and tested for various kind of global distortions, such as image coding may not be efficient for watermarking applications, where the distortions might be restricted in a very narrow portion of the frequency spectrum. We hereby want to propose an objective quality metric which performances do not depend on the distortion frequency range, but we nevertheless want to provide a simplified objective quality metric in opposition to the complex HVS based quality metrics recently made available. The proposed algorithm is generic (not designed for a particular distortion), and exploits the contrast sensitivity function (CSF) along with an adapted Minkowski error pooling. The results show a high correlation between the proposed objective metric and the mean opinion score (MOS). A comparison with relevant existing objective quality metrics is provided

    Reconstruction d'un spectre RMN 2D par maximum d'entropie

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    International audienceLa résonance magnétique nucléaire (RMN) est une méthode moderne de spectroscopie utilisée pour l'analyse de la composition de produits biologiques. Nous nous intéressons dans cet article à l'estimation d'un spectre corrélation T1-T2 à partir de mesures RMN. Les difficultés de l'estimation sont liées au caractère mal-posé de ce problème inverse et à la taille importante des données à traiter. La méthode d'estimation est fondée sur le Maximum d'Entropie et nous proposons deux algorithmes de reconstruction itérative ; le premier est fondé sur l'algorithme de Bryan et Skilling et le second utilise le gradient conjugué non-linéaire. Par ailleurs, la structure du modèle d'observation est avantageusement exploitée pour alléger le coût de calcul sans employer les approximations proposées récemment par Vankataramanan et al. De plus, nous proposons le rajout d'une étape de recherche de pas adaptée à la fonction entropique afin d'assurer une décroissance du critère. Les algorithmes sont évalués sur un exemple synthétique et leur applicabilité est illustrée sur des données réelle

    A robust sensorless output feedback controller of the induction motor drives: New design and experimental validation

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    International audienceIn this paper, a sensorless output feedback controller is designed in order to drive the Induction Motor IM without the use of flux and speed sensors. Firstly, an observer that uses only the measured stator currents is synthesized to estimate the mechanical variables (speed and load torque) and the magnetic variables (fluxes) by structurally taking into account the unobservability phenomena of the Sensorless IM (SIM) and the parametric uncertainties. Secondly, a current-based field oriented sliding mode control, that uses the flux and the speed estimates given by the former observer is developed so as to steer the estimated speed and flux magnitude to the desired references. Since the observer design is independent of the control and depends on theIM parametric uncertainties, a separation principle is introduced to guarantee the practical stability of the whole closed-loop system "observer -controller" ("O-C") according to observability and unobservability time variation. A significant benchmark taking into account the unobservability phenomena of the \textit{SIM} is presented to show the performances of the whole control scheme against experimental set-up

    Porosities accessible to HTO and iodide on water-saturated compacted clay materials and relation with the forms of water: A low field proton NMR study

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    International audienceThe aim of the present work was to quantify accessible porosities for iodide and for a water tracer (HTO) on water-saturated compacted clay samples (illite, montmorillonite and MX-80 bentonite) and to relate these macroscopic values to the forms of water in these porosities (surface/bulk water, external/internal water). Low field proton NMR was used to characterize and quantify the forms of water. This enabled the three different populations (structural OH, external surface and internal surface water) to be differentiated on hydrated clays by considering the difference in proton mobility. An accurate description of the water forms within the different populations did not appear possible when water molecules of these populations were in contact because of the occurrence of rapid exchange reactions. For this reason, it was not possible to use the low resolution NMR method to quantify external surface and bulk water in fully water-saturated compacted clay media at room temperature. This latter information could however be estimated when analyzing the samples at -25°C. At this temperature, a distinction based on the difference in mobility could be made since surface water remained in a semi-liquid state whereas bulk water froze. In parallel, accessible porosities for anions and HTO were determined by an isotopic dilution method using capillaries to confine the materials. HTO was shown to probe the whole pore volume (i.e. the space made of surface and bulk water). When the surface water volume was mainly composed of interlayer water (case of montmorillonite and bentonite), iodide was shown to be located in the pore space made of bulk water. When the interlayer water was not present (case of illite), the results showed that iodide could access a small fraction of the surface water volume localized at the external surface of the clay particles

    Human and automation: a matter of cooperation.

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    International audienceMost of the time, machine design should be considered as human-machine system design in order to solve human-machine cooperation problems. The traditional levels of automation should be re-interpreted in terms of cooperation requirements. A framework is proposed in order to categorise car-driving assistance devices on the basis of human-machine cooperation

    To Reconstruct or Not to Reconstruct: that is the question

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    International audienceThe aim of this study is to use what is traditionally referred as A'-reconstruction in order to compare two possible formalizations of syntax-semantics interface, one based on Generative Grammar and Logical Form (GG), the other built on Categorial Grammar and Variable-Free Semantics (CG-VFS). Considering mainly reconstruction data with resumption in natural language (from French and Jordanian Arabic mostly), I will first give several arguments suggesting that both analyses could be on the right track, both theoretically (both accounts of distributive/reconstructed readings amount to an e-type interpretation of the resumptive pronoun) and empirically (both formalizations correctly predict distributive/reconstructed readings within syntactic islands). Finally, I will present two generalizations about resumption which seem to favor the GG account based on actual reconstruction, one concerning the type of distributive reading (functional vs pair-list), the other linked to a distinction between weak and strong resumption
    HAL-Univ-Nantesis based in FR
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