Sliding mode controller for robust force control o hydraulic actuator with environmental uncertainties

In this paper, a reduced order linear model is selected to describe the hydraulic servo-actuator with large environmental uncertainties. The exploitation in simulation of the perturbed 5th order linear model is enough for the first approach, that is to say, before experimentation to value the studied law control potential. Because its robust character and superior performance in environmental uncertainties, a sliding mode controller, based on the so called equivalent control and robust control components is designed for control of the output force to track asymptotically the desired trajectory with no chattering problems. A comparison with H-infinity controller shows that the proposed sliding mode controller is robustly performant.Keywords : Sliding mode control, hydraulic Servo-Actuator, output tracking

The impact of the image processing in the indexation system

This paper presents an efficient word spotting system applied to handwritten Arabic documents, where images are represented with bag-of-visual-SIFT descriptors and a sliding window approach is used to locate the regions that are most similar to the query by following the query-by-example paragon. First, a pre-processing step is used to produce a better representation of the most informative features. Secondly, a region-based framework is deployed to represent each local region by a bag-of-visual-SIFT descriptors. Afterward, some experiments are in order to demonstrate the codebook size influence on the efficiency of the system, by analyzing the curse of dimensionality curve. In the end, to measure the similarity score, a floating distance based on the descriptor’s number for each query is adopted. The experimental results prove the efficiency of the proposed processing steps in the word spotting system

Combined cosine-linear regression model similarity with application to handwritten word spotting

The similarity or the distance measure have been used widely to calculate the similarity or dissimilarity between vector sequences, where the document images similarity is known as the domain that dealing with image information and both similarity/distance has been an important role for matching and pattern recognition. There are several types of similarity measure, we cover in this paper the survey of various distance measures used in the images matching and we explain the limitations associated with the existing distances. Then, we introduce the concept of the floating distance which describes the variation of the threshold’s selection for each word in decision making process, based on a combination of Linear Regression and cosine distance. Experiments are carried out on a handwritten Arabic image documents of Gallica library. These experiments show that the proposed floating distance outperforms the traditional distance in word spotting system

Segmentation-free Word Spotting for Handwritten Arabic Documents

In this paper we present an unsupervised segmentation-free method for spotting and searching query, especially, for images documents in handwritten Arabic, for this, Histograms of Oriented Gradients (HOGs) are used as the feature vectors to represent the query and documents image. Then, we compress the descriptors with the product quantization method. Finally, a better representation of the query is obtained by using the Support Vector Machines (SVM)

Reduced complexity of decoding algorithm for Irregular LDPC Codes using Split Row Method” accepted

Abstract In this paper, we have proposed a novel method of decoding algorithm of irregular LDPC codes. A reduced complexity LDPC decoding method for regular LDPC code is extended to irregular LDPC codes. We present in this paper a full description of this method and its benefits for various row weight and length code word. The Split-Row method makes column processing parallelism easier to exploit and significantly simplifies row processors. Recently, irregular LDPC codes have received a lot of attention by many advanced standard, such as WiFi, WiMAX Mobile and digital video broadcasting (DVB-S2). Hence the idea to develop the "Split-Row Method" for irregular LDPC codes. In this context, we have performed an implementation on MATLAB of an irregular LDPC codes with different code word and code rate; simulation results over an additive white Gaussian channel show that the error performance of high row-weight codes with Split-Row decoding is within 0.3-0.5 dB of the Min-Sum algorithm. The study result shows that the "Split Row Method" is better for irregular code than regular LDPC codes

Modélisation paramètrique 3-D fondée sur la décomposition de Wold (applications au filtrage de blocs sismiques 3-D)

Ce mémoire porte sur la modélisation de blocs 3D d'images texturées. L'objectif principal est de développer de nouveaux modèles paramétriques 3D qui permettent de caractériser une grande classe de textures. L'outil mathématique mis à contribution pour construire ces modèles est la décomposition de Wold des processus aléatoires discrets multidimentionnels. L'étude réalisée montre que tout bloc d'images texturées, considéré comme une réalisation d'un processus aléatoire homogène 3D, est la somme de quatre composantes orthogonales : une composante purement aléatoire, une composante harmonique et deux composantes évanescentes dites champ évanescent de type 1 et champ évanescent de type 2. Pour exploiter ce résultat théorique, nous proposons des modèles paramétriqaues adéquats pour approximer séparément les quatre composantes. a travers différentes études expérimentales, nous montrons que la modélisation fondée sur la décomposition de Wold 3D offre la possibilité de caractériser des blocs d'images présentant séparément ou à la fois les trois aspects fondamentaux des textures 3D : l'aspect aléatoire, l'aspect périodique et l'aspect directionnel. Les modèles proposés ont été utilisés pour le fitrage des blocs sismiques 2D fournis par le laboratoire commun "LASIS" CNRS-TOTAL. Dans ce contexte applicatif la décomposition de Wold 3D consiste, d'une part, à identifiier et à séparer les différents signaux qui composent la donnée sismique, et d'autre part, à distinguer parmi les composantes extraites celles qui représentent le signal sismique, après quoi le filtrage devient aisé.BORDEAUX1-BU Sciences-Talence (335222101) / SudocSudocFranceF

Contribution to Synchronization and Tracking Modelisation in a CDMA Receiver

We propose and analyze a noncoherent receiver with PN code tracking for direct sequence code division multiple access (DS-CDMA) communication systems. We employ the delay-lock loop (DLL) architectures for the tracking stage. The choice of DLL parameters is studied with special focus on DS-CDMA communication systems and orthogonality conditions. We described the modeling and simulation of the NCO using hardware description language VHDL. Details of the VHDL implementation are shown

Observer design for a fish population model

International audienceOur aim is to apply some tools of control to fishing population systems. In this paper we construct a non linear observer for the continuous stage structured model of an exploited fish population, using the fishing effort as a control term, the age classes as a states and the quantity of captured fish as a measured output. Under some biological satisfied assumptions we formulate the observer corresponding to this system and show its exponential convergence. With the Lie derivative transformation, we show that the model can be transformed to a canonical observable form; then we give the explicit gain of the estimation.Le but de ce travail est d'appliquer des outils de contrôle aux systèmes de population de pêche. on construit un observateurpour un modèle continu structuré en age de population de pêche exploitée qui tient compte des pré-recrutés. Les variables dumodèle: l'effort de pêche, les classes d'age et la capture sont considérés respectivement comme contrôleur, états du systèmes et sa sortie mesurée. Le changement de variables basé sur les dérivés de Lie nous a permis de mettre le système sous une forme canonique observable. La forme explicite de l'observateur est finalement donnée

Crack Detection and Classification in Moroccan Pavement Using Convolutional Neural Network

Crack is a condition indicator of the pavement’s structure. Generally, crack detection is an essential task for effective diagnosis of the road network. Moreover, evaluation of road quality is necessary to ensure traffic security. Since 2011, a periodic survey of approximately 57,500 km of Moroccan roads has been performed using an inspection vehicle (SMAC) which is equipped with high resolution cameras and GPS/DGPS receivers. Until recently, the teams of the National Center for Road Studies and Research (CNER) analyzed road surface states by visualization of pavement surface image sequences captured by the Multifunctional Pavement Assessment System (SMAC) in order to detect defects in road surfaces and classify them according to their type. However, this method involves manual processing and is complex, time consuming and subjective. In this paper, we propose an automated methodology for crack detection and classification in Moroccan flexible pavements using Convolutional Neural Networks (CNN). Transfer learning is also applied by testing a pre-trained Visual Geometry Group 19 (VGG-19) model. For the dataset used in this paper, the results indicate that good crack detection and classification are achieved using both models

Robust Stabilization of Hybrid Periodic Orbits of Passive Walking Mechanisms

Abstract In this paper, we develop a control law to stabilize passive periodic orbits (without external enregy) of a class of autonomous mechanical systems subject to model uncertainties. The dynamic model of such systems is Lagrangian and include multiple phases (modes) and discrete jumps (e. g walking robots). The approach is based in the notion of Controlled Symmetry (due to spong) which capture the effect of the control input on the invariance of the system Lagrangian under group action. Simulation results are given for a simple robotic system I