Liste des communications
Logique Floue et Traitement des Images deRadiographie Indutrielles
La segmentation est une opération très importantedans la chaîne du traitement d'images puisqu'elle contribuedirectement dans le diagnostic et la prise de décision. Dans cetravail nous proposons une approche de segmentation basée surla classification non supervisée floue en utilisant l'algorithmeFCM (fuzzy C-means), appliquée aux images de radiographie desoudure. Le but de cette segmentation est de détecter et delocaliser d’éventuels défauts qui peuvent être produits parl’opération de soudage. Voir les détails
Mots clés : Segmentation classification, étiquetage, images radiographie de soudure, contrôle non destructif, défaut de soudure
Extraction of weld defect from radiographic images using the level set segmentation without reinitialization
All level set based image segmentation methods arebased on an assumption that the level set function is close to asigned distance function (SDF). Small time step and costly reinitialization procedure must be applied to guarantee this assumption, and in order to calculate the gradient, simple numerical schemes, based on finite differences, are applied. Inthis paper, in order to achieve higher order accuracy in thetemporal discretization, we have used Total Variation Diminishing (TVD) Runge Kutta (RK) methods. The spatial derivatives are determined by using the Weighted Essentially Non-Oscillatory methods (WENO-5) that accurately capture theformation of sharp gradients in the moving fronts. In the otherhand, we have used the level set method without re-initializationin order to speed up the evolutionary process. Experiments results show that we have obtained good results both on syntheticand real images. Voir les détails
Mots clés : Image segmentation; active contour; level set
Fast Waveguide Filter Synthesis, using the Mode Matching Method for Analysis and Practical Swarm Optimization
In this paper, we give two examples of rectangular waveguide bandpass filter synthesis. Starting from the filter specifications (order of the filter, position of zeros, band-edge frequencies, and passband return loss) our aim was to realize one program that makes all steps of the filter synthesis (calculate the coupling matrix, create the equivalent circuit, convert the equivalent circuit to waveguide structure, analyze this structure, and then optimize its dimensions), and doing this as fast as possible (less than two minutes). For the coupling matrix we used the Atia and Williams’s method, for the analysis we used the mode matching method, which is the most adequate for this kind of structures, and for the optimization we used the Practical Swarm Optimization PSO. The complete combination has been successfully applied for several waveguide filters synthesis. Voir les détails
Mots clés : waveguide bandpass filter, Practical Swarm Optimization, mode matching
Contrôle des Transits de Puissance par l’Utilisation d’un UPFC Connecté à une Ligne de Transmission
The FACTS technologies involve conversion andswitching of power electronics in the range of a few tens to few hundred megawatts. The new state devices such as MOSFETs, IGBTs, GTOs and also other suitable power electronic devices are used as controlled switches in FACTS devices. The universal and most flexible FACTS device is the Unified Power Flow Controller “UPFC”, this device is the combination of three compensators characteristic; i.e., impedance, voltage magnitude and phase angle, that are able to produce a more complete compensation [1]. Voir les détails
Mots clés : FACTS, MOSFETs, IGBTs, GTOs, UPFC
Task Performance Evaluation for Industrial Robots
Integrated multi-modal Supervisory Control Systems(ISCS) are a new generation of complex and synergistic Human-Machine Interaction Systems (HMIS). This paper deals withmulti-modal interaction and control applied to HRS. A taskperformance evaluation technique dedicated for multi-modalinteraction and control is proposed. It enables comparison oftask performance carried out by using different selection ofcontrol modes or by different operators. Objective andsubjective performance measures are defined. Based on theanalytical hierarchy process method (AHP) which takes intoaccount qualitative and quantitative attributes and criteria.Experimental results have been carried out and somepreliminary results will be presented concerning industrialmanipulators. Voir les détails
Mots clés : Task performance evaluation, Robotics, human factors, Analytical Hierarchy Process, Adaptive supervisory control, Multi-modal interaction, Graphical-user interface.
Etude de la Performance d’un Dispositif STATCOM Utilisée pour Compenser la Puissance Réactive au Point de Raccordement
The industrial extension during the last decades led to increasing considerable requirements in the electric power, in spite of the significant energy production.The FACTS concept “Flexible Alternative Current Transmission Systems” regroups all devices to basis of electronics of power that permits to improve the exploitation of the electric network. The technology of these systems “static switches” assure a speed superior to the one of the classic electromechanical systems.The objective of this paper is to study the functions of control offered by the STATCOM “STATic COMpensator” in the regulation of the voltage by compensation of the reactive energy. Voir les détails
Mots clés : FACTS, static switches, STATCOM
Structural, electronic properties of compounds AlAs, BAs and AlP, BP
We determine the structural, electronic properties of AlAs, BAs and AlP BP alloys using the full potential-linearized augmented plane wave method (FP-LAPW) within the density functional theory (DFT). The exchange-correlation potential is treated by the generalized gradient approximation (WC-GGA). The investigation on the effect of composition on lattice constant, bulk modulus and band gap shows not linear dependence on the composition. The ground state properties such as lattice constant, bulk modulus, pressure derivative of the bulk modulus are in good agreement with numerous experimental and theoretical data. For the electronic properties, we used the mBJ-LDA approximation. The bowing of the fundamental gap versus composition predicted on the composition is in a good agreement with experiment. Voir les détails
Mots clés : FP-LAPW, DFT, Ternary alloys, bands structure, bowing gap and thermodynamic propertie
Optimisation Par Essaim de Particules de la Pénalité Floue Pour la Reconstruction d’images a Partir de Projections en Tomographie-X
La résolution du problème inverse de reconstruction se fait opposée par plusieurs obstacles surtout dans le cas 3D et 4D (la vidéo), parmi ces problèmes on peut citer le dimensionnement des matrices, l’espace mémoire nécessaire pour le calcul et le temps de calcul. On utilise l’optimisation par essaim de particules à la place des algorithmes génétiques. On peut voir que la PSO n’utilise pas les opérateurs de reproduction comme le croisement ou la mutation et elle s’intéresse seulement à l’allure des individus pour aboutir à la meilleure solution de la population. Voir les détails
Mots clés : Computed tomography, Non destructive testing, Bayesian Inference, Fuzzy inference, Particle Swarm Optimization
Solution of the State-Space Linear Fractional Order Systems
A useful representation of fractional order systems is the state space representation. For the linear fractional systems of commensurate order, the state space representation is defined as for regular integer state space representation with the state vector differentiated to a real order. This paper presents a solution to the state space linear fractional systems of commensurate order. The solution is obtained using a technique based on functions of square matrices and the Cayley-Hamilton Theorem. The solution is calculated in the form of a linear combination of suitable fundamental functions. The basic ideas and the derived formulations of the technique are presented. An example is also given to demonstrate the effectiveness of the presented analytical approach. Voir les détails
Mots clés : Cayley-Hamilton theorem, fractional order differential equations, fractional state space, Functions of matrices, rational function
Weld Radiographic Images Segmentation and Restoration Via Local Binary Fitting Energy and Binary Level Set
The present paper is devoted to discuss a region-based active contour model formulated via level set method. Region-based models have more advantages over edge based models, especially by introducing local statistical image intensities instead of the global statistical image intensities. This propriety makes those models well adapted to segment weld radiographic images in the aim to get image with less complexity and to extract weld defects in order to use them in NDT (Non Destructive Testing). Voir les détails
Mots clés : segmentation, Restoration, weld radiographic images, region-based active contours, LBF model, Level set