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International audience; In this paper a sensitivity analysis of trajectories w.r.t. wind effects is proposed. This analysis will allow to specify wind estimates properties as well as control reactiveness characteristics to ensure accurate guidance in real atmosphere. The mathematic model developed for flight dynamics is intended to take into account wind gust effects on AoA, sideslip angle and airspeed. A two layer Nonlinear Dynamic Inversion (NDI) structure has been considered to control fast and slow dynamics. In order to test the proposed approach, a full six degrees of freedom Matlab model with trained Neural Networks to emulate a Boeing 737-200 was developed.

International audience; The monitoring of rolling element bearing is indexed as a critical task for condition-based maintenance in various industrial applications. It allows avoiding unscheduled maintenance operations while decreasing their cost. For this purpose, various methodologies were developed to ensure accurate and efficient monitoring. In this context, this paper proposes an approach for bearing faults early diagnosis based on the variational mode decomposition (VMD), used as a notch filter for dominant mode cancellation, and a machine learning approach, namely the one-dimensional convolution neural network (1D-CNN), for detection and diagnosis purposes. Specifically, the proposed approach first performs features extraction using VMD for fault detection, and then triggers to multi-scale features extraction using CNN convolution and pooling layers for classification and diagnosis. The proposed bearing faults detection and diagnosis approach is evaluated, in terms of robustness and performances, using the well-known Case Western Reserve University experimental dataset. In addition, performances are evaluated versus well- established demodulation techniques, in terms of faults detection, and machine learning strategies, in terms of faults diagnosis. The achieved results show that the proposed VMD notch filter-based 1D-CNN approach is clearly promising for bearing degradations monitoring.

The objective is to develop a control algorithm for quadrotors that guarantees a good compromise robustness/performance in presence of external disturbances. Thus, we investigate and apply a nominal model-based control strategy doted by a robustness boosting mechanism. This latter, uses an Extended State-based Observer (ESO) to estimate the uncertainties and the various disturbances. The obtained controller is augmented by an additional input, which is derived via a sliding modes framework to handle the estimation errors and ensure asymptotic stability. The primary results are shown through numerical simulations.

International audience; Due to their structure and complexity, chaotic systems have been introduced in several domains such as electronic circuits, commerce domain, encryption and network security. In this paper, we propose a novel multidimensional chaotic system with multiple parameters and nonlinear terms. Then, a two-phase algorithm is presented for investigating the chaotic behavior using bifurcation and Lyapunov exponent (LE) theories. Finally, we illustrate the performances of our proposal by constructing three (03) chaotic maps (3-D, 4-D and 5-D) and implementing the 3-D map on Field-Programmable-Gate-Array (FPGA) boards to generate random keys for securing a client–server communication purpose. Based on the achieved results, the proposed scheme is considered an ideal candidate for numerous resource-constrained devices and internet of the things (IoT) applications.

International audience; Failure detection and diagnosis are of crucial importance for the reliable and safe operation of industrial equipment and systems, while gearbox failures are one of the main factors leading to long-term downtime. Condition-based maintenance addresses this issue using several expert systems for early failure diagnosis to avoid unplanned shutdowns. In this context, this paper provides a comparative study of two machine-learning-based approaches for gearbox failure diagnosis. The first uses linear predictive coefficients for signal processing and long short-term memory for learning, while the second is based on mel-frequency cepstral coefficients for signal processing, a convolutional neural network for feature extraction, and long short-term memory for classification. This comparative study proposes an improved predictive method using the early fusion technique of multisource sensing data. Using an experimental dataset, the proposals were tested, and their effectiveness was evaluated considering predictions based on statistical metrics.

The objective of this thesis is the study of surface EMG signal and its application for Parkinson's disease (PD) diagnosis. Three problems have been investigated, namely the segmentation of surface EMG signals, the classification or diagnosis of PD and the decomposition of the surface EMG signal into TPAUM. In the first problem, two techniques have been introduced for EMG signal segmentation. The first one is an unsupervised method called ALED and the second one is a supervised one based on the use of HMM models. These techniques are developed for the detection of the bursts EMGactivity and their monitoring.To deal with the second problem, we have proposed two diagnostic systems for PD detection.The first one is based on the analysis of the burst EMG activity using (and comparing) different features and different classification techniques from the literature and the second one is based on HMMs.For the last problem, we have developed a new technique for the EMGs signal decomposition into TPAUM based on sparce source separation., L'objectif de cette thèse est l’analyse des signaux EMG de surface et leur application au diagnostic de la maladie de Parkinson (MP). Trois points ont été abordés dans cette thèse à savoir la segmentation des signaux EMG de surface, la classification ou diagnostic de la MP basé sur l'apprentissage machine et la décomposition du signal EMG de surface en TPAUM. Dans le premier point, nous avons développé, deux techniques originales. La première, ALED et ses variantes, est non supervisée alors que la seconde est supervisée et est basée sur l’utilisation des modèles HMM. Ces techniques ont été développées pour la détection des bouffées d’activités EMG et leur analyse. Dans le second point, nous avons proposé deux systèmes de diagnostic de la MP. Le premier est basé sur l’analyse des bouffées d’activité EMG en utilisant et comparant différents descripteurs et différentes techniques de classification existantes dans la littérature. Le deuxième système est basésur les HMM. Dans le dernier point, une méthode de décomposition du signal EMG de surface en TPAUM est proposée, basée sur la séparation de sources via leur parcimonie temporelle.

International audience; The primary aim of this study is to investigate the influence of an upstream cylindrical rod on the laminar separated boundary layer that develops on a symmetrical profile wing operating at a Reynolds number of Re c = 4.45 × 10 5. To get further insight onto the aerodynamic performances of this wing at low Reynolds number, numerical simulations with a transitional turbulence model are performed with the ANSYS-Fluent software. The passive flow control technique is applied by setting up a cylindrical rod of diameter d upstream of a NACA-0012 airfoil of chord lenght c. The dimensionless rod diameter with respect to the chord length is d/c = 2/150. Simulations are carried out over a wide range of angles of attack for both the baseline case and the controlled case by the passive proposed technique. The effects of the wing incidence on the parietal pressure distributions on the suction surface of the wing are examined. The results show that the Laminar Separation Bubble that is formed on the upper surface is moving upstream toward the leading edge as the incidence is increased. Moreover, qualitative analysis of the transition zone revealed that presence of the wing in the rod wake exerted considerable effect on the pressure coefficient. Particularly, this passive turbulence generator contributes to eliminate the boundary layer separation

International audience; It is relevant to develop an adequate control algorithm for quadrotors that guarantees a good compromise robustness/ performance. This compromise should be ensured with or without external disturbances. In this paper, we investigate and apply a revisited formulation of a reference model-based control strategy by introducing a boosting mechanism. This mechanism uses an Extended State-based Observer (ESO) to estimate the uncertainties and variety of disturbances. The estimation is continually updated and rejected from the main control loop. The reinforcement principle is inspired from the popular Active Disturbance Rejection Control (ADRC) technique in order to enhance the robustness ability of a nonlinear reference model-based control strategy (i.e. Interconnection and Damping Assignment-Passivity Based Control (IDA-PBC)). The obtained controller is augmented by an additional input, which is derived via sliding modes framework to handle the estimation errors and ensure asymptotic stability. This combination leads to promising results by improving the nominal control technique. The primary results are shown through numerical simulations and are confirmed, experimentally, with several scenarios.

International audience; With a convenient concatenation of a convex relaxation-based detector and a simple greedy algorithm, we propose an improved Post Detection Sparse error Recovery (PDSR) approach for massive Multiple Input Multiple Output (m-MIMO) systems that, in particular, transmit QAM signals. The proposed PDSR approach can perform well in situations, where the classical one, either acts poorly or completely fails. We further propose an Alternating Direction Method of Multipliers (ADMM)-based solver for the convex detector, which is advantageous in maintaining an affordable complexity to the overall proposed detection scheme. Numerical experiments show the efficiency of our approach, especially when applied to overloaded m-MIMO systems.

International audience; In this paper, we propose a new receiver for detecting signals in large-scale Spatially Multiplexed (SP) Multiple-Input-Multiple-Output (MIMO) systems that may have fewer receive antennas than transmitted symbols (overloaded case). Relying on the idea of Finite-Alphabet Sparse (FAS) detection, we formulate the Maximum Likelihood (ML) criterion as a Difference-of-Convex (DC) programming problem that can be simply and efficiently solved using the Concave-Convex Procedure (CCP) technique. Since, the considered problem is non-convex, we theoretically discuss the behavior of the derived algorithm. Numerical experiments confirm the superiority of the proposed detection scheme, when compared with recent detection methods based on convex optimization, in a variety of large-scale MIMO transmission scenarios including the overloaded case.

Over the past few years, nanocellulose (NC), cellulose in the form of nanostructures, has been proved to be one of the most prominent green materials of modern times. NC materials have gained growing interests owing to their attractive and excellent characteristics such as abundance, high aspect ratio, better mechanical properties, renewability, and biocompatibility. The abundant hydroxyl functional groups allow a wide range of functionalizations via chemical reactions, leading to developing various materials with tunable features. In this review, recent advances in the preparation, modification, and emerging application of nanocellulose, especially cellulose nanocrystals (CNCs), are described and discussed based on the analysis of the latest investigations (particularly for the reports of the past 3 years). We start with a concise background of cellulose, its structural organization as well as the nomenclature of cellulose nanomaterials for beginners in this field. Then, different experimental procedures for the production of nanocelluloses, their properties, and functionalization approaches were elaborated. Furthermore, a number of recent and emerging uses of nanocellulose in nanocomposites, Pickering emulsifiers, wood adhesives, wastewater treatment, as well as in new evolving biomedical applications are presented. Finally, the challenges and opportunities of NC-based emerging materials are discussed.

Axial flow fans are used in many fields in order to ensure the mass and heat transfer from air, chiefly in the heating, ventilation and air conditioning industry (HVAC). A more proper understanding of the airflow behavior through the systems is necessary to manage and optimize the fan operation. Computational fluid dynamics (CFD) represents a real tool providing the ability to access flow structures in areas that measuring equipment cannot reach. Reducing the leakage flow rate, inherent in operation, by synthetic-jet techniques improves performance. This paper presents the CFD results performed on a hollow blade fan developed by our team. The leakage flow is controlled by blowing air from 16 designated circular holes and arranged on the fan shroud. We discuss the results for two rotational speeds (1000 and 2000 rpm) and two injection rates (400 and 800 L/min). The numerical results consistent with the experimental show, for the low rotation speed and high injection ratio, significant gains in power (53%), torque (80%) and leakage flow rate (80%).

International audience; This paper presents a new approach to perform 4D trajectory tracking for transportation aircraft. As current systems are extensions of 3D guidance with overfly time constraints at some given points and no general control framework has been developed for 4D guidance of a transport aircraft; the main goal of the proposed approach is to introduce a new method based on the inversion of the flight dynamics while avoiding numerical issues. A six degree of freedom model for a wide body transportation aircraft was developed in Matlab to provide a numerical simulation of the proposed approach, showing satisfying results.

A heterogeneous wireless environment is composed of different radio access technologies (RATs) including IEEE standards (e.g., Wi-Fi) and 3GPP (e.g., 2G, 3G, 4G, 5G), each with different coverage and different capacity to cater for diverse service requirements. In such an environment, multiple access networks could be available for a mobile user. Each user can run multiple applications that have particular Quality of Service (QoS) requirements. Hence, it would be beneficial for a multi-interface terminal to simultaneously use two or more interfaces to gain in performance. However, using multiple networks simultaneously may consume more energy than using only one interface. Therefore, energy consumption should be considered as a criterion in the Flow/Interface Association (FIA). This paper presents a novel method called Smart Tabu Search (STS) that takes into account network conditions, the monetary cost of the network, QoS requirements of the applications, user preferences, and energy consumption of the mobile device to select the optimal FIA that achieves the best trade-off among all the considered criteria. We validate our proposal using both simulations and testbed experiments.

Predicting the expected performance of Wireless Sensor Networks (WSNs) is the key to their successful deployment. This paper investigates the following fundamental problem: how to judiciously plan the physical and the logical topologies of a WSN so that performance demands including network connectivity, sensing coverage quality, reliability, and lifetime are all satisfied with the least possible cost. To handle the uncertainty related to sensor connectivity and coverage, we devise a probabilistic-based communication cost model, and we exploit the belief functions theory to define a generic evidence fusion scheme that captures several characteristics of real-world applications. The uncertainty-aware cluster-based WSNs deployment problem is formulated as a multi-objective binary nonlinear and non-convex optimization problem, and an efficient heuristic using genetic algorithms is investigated. Using both simulations and testbed-based experiments, we show that the proposed deployment approach can fulfill the user performance needs, which confirms that the deployment of real-world fusion-based WSNs with predictable performance is possible.

International audience; This paper proposes a method to reach the equivalence between an IMC and a PI controller regardless of the model order. To this end, the key idea consists of using a specific IMC filter that exhibits a good level of robustness and further leads to get a structure of a PI controller whatever the order of the model is. The developed procedure constitutes the main contribution of this paper. To meet given set of specifications, the controller parameters are tuned through a straightforward analytic way using the dynamics of the tracking error. Furthermore, in order to evaluate the efficiency level of this procedure, an application to control an autonomous vehicle is described and the simulation results are shown to be satisfactory.

In this paper, 3D numerical simulations have been carried out to enhance the understanding of a flow over a passive control device composed of micro cylinder with, d/c = 1.34% placed in the vicinity of NACA0012 aerofoil wing, by means of γ–Reθt transition sensitive turbulence model meant to predict the separation induced by transition achieved for aerofoils operating at moderate Reynolds number (Re = 4.45×105). Results show that the separation of the boundary layer has been eliminated by the passive static vortex generator at stall regime due to the injection of free-stream momentum to the boundary layer. The early transition to turbulent state overcomes the local flow deceleration of an adverse pressure gradient and remains sticked to the wall the boundary layer. Furthermore, the wing aerodynamic performance are improved as drag is reduced and lift is enhanced which is straight forward linked to the lift to drag ratio gain that varies from 22.68% to 134.17% at post stall angles of attack.

This paper deals with a hybrid joint diagonalization (JD) problem considering both Hermitian and transpose congruences. Such problem can be encountered in certain non-circular signal analysis applications including blind source separation. We introduce new Jacobi-like algorithms using Givens or a combination of Givens and hyperbolic rotations. These algorithms are compared with state-of-the-art methods and their performance gain, especially in the high dimensional case, is assessed through simulation experiments including examples related to blind separation of non-circular sources., Supplementary material (ref. [18]) is included in this file

Companies are increasingly confronted with the problems caused by their reliance on information systems. They are thus forced to implement a process of security requirements derivation starting from risks analysis. This process requires a thorough analysis of the organizational context. The purpose of this article is to propose a security meta model enriched by an ontology of the context. To this end, we propose (i) the development of a context ontology based on the ISO / IEC 27000: 2018 security standard,(ii) an approach to enrich the security meta model with context ontology. This enrichment is carried out in two phases. The first is related to the identification and extraction of elements of the context of the enterprise. The second concerns the determination of the security criteria of the assets of the organization to be protected and (iii) the application to a real case which also serves as a first step in the validation of our approach., Les entreprises sont confrontées de plus en plus aux problèmes induits par leur dépendance vis-à-vis des systèmes d'information. Elles se voient ainsi contraintes à mettre en oeuvre un processus de dérivation des exigences de sécurité à partir de l'analyse des risques encourus. Ce processus requiert au préalable une analyse approfondie du contexte organisationnel. Le but de cet article est de proposer un méta modèle de sécurité enrichi par une ontologie du contexte. A cette fin, nous proposons (i) le développement d'une ontologie du contexte fondée sur la norme de sécurité ISO/CEI 27000 : 2018, (ii) une démarche d'enrichissement du méta modèle de sécurité par l'ontologie du contexte. Cet enrichissement est réalisé en deux phases. La première est relative à l'identification et à l'extraction des éléments du contexte de l'entreprise. La seconde concerne la détermination des critères de sécurité des actifs de l'organisation à protéger et (iii) l'application à un cas réel qui sert aussi de première étape dans la validation de notre démarche.

International audience; An unmanned aerial vehicle (UAV) has grown rapidly the last years. They are being engaged in many types of missions, ranging from military to agriculture passing from entertainment and rescue or even delivery. This work consist to ensure the convergence of positions and yaw angle, to their desired trajectories while maintaining stability of roll and pitch angle. For this, formulate this problem to an optimal control problem which minimizes the distance between state and desired state in free final time. Our contribution is to use the Bocop software to solve this problem. And to implement Shooting method with Matlab software.

International audience; The main objective of an energy regulation of a building is to maintain internal thermal comfort, as well as minimize energy consumption, or reduce the peak of electrical consumption. The dynamic programming has been used to minimize a cost function, accounting for a high peak electricity tariff, under constraints related to comfort (minimal temperature, maximal temperature variation) and the maximum heating power. The proposed energy management consists in over-heating the building during the hours before the peak knowing in advance the weather, occupation and internal gains for the day. The method has been tested in a case study corresponding to a house of a four-person family with performance levels: high construction and poorly insulated old house.

We study algorithms to compute the Shapley value for a cooperative game on a lattice L Σ = (F Σ , ⊆) where F Σ is the family of closed sets given by an implicational system Σ on a set N of players. The first algorithm is based on the generation of the maximal chains of the lattice L Σ and computes the Shapley value in O(|N | 3 .|Σ|.|Ch|) time complexity using polynomial space, where Ch is the set of maximal chains of L Σ. The second algorithm proceeds by building the lattice L Σ and computes the Shapley value in O(|N | 3 .|Σ|.|F Σ |) time and space complexity. Our main contribution is to show that the Shapley value of weighted graph games on a product of chains with the same fixed length is computable in polynomial time. We do this by partitioning the set of feasible coalitions relevant to the computation of the Shapley value into equivalence classes in such a way that we need to consider only one element of each class in the computation.

Nowadays, the manufacture of turbomachinery is conditioned by more and more restrictive rules. The industrial challenge for researchers has to consider optimal solutions to reduce sources of energy loss, instability and noise, particularly the tip clearance flow (leakage flow rate). Preliminary actions have been developed at Arts & ParisTech on rotational molding process used for the automobile cooling axial fan. The idea of this work is to use the hollow shape induced by rotational molding process in order to exploit it in the control of tip clearance flow through rotary steady air injection. For this, the shroud ring is composed of injection holes oriented in such away to reduce both of leakage flow rate and the torque. In this work, the thesis focuses on three parts. The first concerns the build of the fan by rotational molding process. The second concerns the experimental study carried out in the ISO 5801 test bench. This study involves the realization of drive system dedicated to rotary steady air injection, metrology for performance determination and the characterization of the near wake axial velocity. The third part deals with the numerical modeling of efficient experimental conditions, then the extrapolation of work towards high injection rates. For this latter, it is possible to cancel leakage flow rate with a considerable gain of the torque thus putting the fan in autorotation., Aujourd’hui, la fabrication des turbomachines est conditionnée par des normes de plus en plus restrictives. L'enjeu industriel pour les chercheurs est d'envisager des solutions optimales visant à réduire les sources de perte d'énergie, d'instabilité et du bruit, en particulier l'écoulement de jeu (débit de fuite). Des actions préliminaires ont été élaborées à Arts & Métiers ParisTech sur le rotomoulage du ventilateur axial de refroidissement d'automobile. L'idée de ce travail est d'utiliser la forme creuse induite par le rotomoulage afin de l'exploiter dans le controle de l'écoulement de jeu radial par soufflage rotatif. Pour cela, la virole comporte des trous d'injection orientés de façon à réduire simultanément le débit de fuite et le couple. Dans ce travail, trois parties ont été traité. La première concerne la réalisation du ventilateur par rotomoulage. La deuxième concerne l'étude expérimentale menée dans le banc d'essai ISO 5801. Cette étude comporte la réalisation d'un montage dédié au contrôle par soufflage rotatif, la métrologie menée pour la détermination des performances globales et la caractérisation de la vitesse axiale du sillage proche. La troisième partie traite la modélisation numérique des conditions expérimentales rentables ensuite l'extrapolation du travail vers des taux d'injection importants. Pour ce dernier, on arrive à annuler le débit de fuite avec un gain considérable du couple mettant ainsi le ventilateur en autorotation.

International audience; Our aim is to solve a problem of optimal control with free final time using the Pontryagin's maximum principle. As an illustration, we consider a navigation problem which is solved analytically and numerically by the shooting method in the case without constraint. The two approaches are compared. In the second case, we solve numerically the same problem with constraint on the state. At the end, we prove the convergence of the method for the second case.

International audience; In the near future, unmanned aerial vehicles are probably going to be included in the airspace. Therefore, air traffic management needs to be enhanced in terms of reliability, safety, and accuracy. The main objective of this paper deals with a quadrotor flight control system that generates the necessary control laws to perform accurately, as well as possible, the reference flight trajectories. In this paper, a new quadrotor flight dynamics is developed, including an adopted wind model component where a study of the minimum phase and observability conditions is performed. Based on an adaptive backstepping control algorithm, a developed flight control system generates nonlinear control laws in an iterative and systematic procedure design. In addition to some simulations in a no-wind situation, the proposed adaptive flight control system is simulated in a windy flight condition. The design of adaptation laws according to some quadrotor parameters is developed, and the global stability of the proposed flight control system is guaranteed using the Lyapunov theory. Numerical simulations are performed for the quadrotor engaged in complex trajectory tracking, and obtained results show the feasibility and effectiveness of the proposed control approach.

International audience; In this article, after introducing fuzzy-dual numbers, functions and functionals, the optimization of a fuzy-dual functional is considered through an extension of Euler's condition. Then, once uncertainty is imbedded in a fuzzy-dual dynamical system, the optimization of such systems is considered, leading to an extended Hamilton-Jacobi-Bellman equation to characterize optimal fuzzy-dual solutions.

Navigation technology has an important role in designing intelligent vehicles and advanced robots. To have a continuous navigation solution that does not suffer from interruption, GPS (Global Positioning System) data is merged with relative positioning techniques such as inertial navigation system (INS) or odometry (Odm). To accomplish the reliability and integrity desired, it is therefore necessary to take into account physical capabilities and limitations of each sensor during navigation. A fuzzy switcher controller (FSC) is well suited for this task. FSC is an Expert rule-based method for choosing the best fusion from multiple redundant integration methodologies (GPS/INS, GPS/Odometry, Odometry/INS or GPS/INS/Odometry) based on navigation conditions and accuracy of the navigation systems.

International audience; This study presents the conception, simulation, realisation and characterisation of a patch antenna made of a composite based on polyaniline (PANI) and multiwall carbon nanotubes (MWCNTs). The antenna is designed to operate at the frequency of 4.5 GHz; the dielectric substrate used is Rogers RT/Duroid® 5870 which has a dielectric permittivity of 2.33 and a loss tangent of 0.0012. The conductive polymer (PANI/MWCNTs) fabricated has a conductivity of 4500 S/m. The performance of the proposed antenna is investigated as a function of the thickness of the conductive polymer. The experimental results show an antenna gain of 5.18 dB for a PANI/MWCNTs thickness of 110 μm. The results obtained suggest that this kind of conductive polymers are good candidates for future applications based on organic electronics.

International audience; INS-GPS integration is a fundamental task used to enhance the accuracy of an inertial navigation system alone. However, its implementation complexity has been a challenge to most embedded systems. This paper proposes a low-cost FPGA-based INS-GPS integration system, which consists of a Kalman filter and a soft processor. Moreover, we also evaluate the navigation algorithm on a low-cost ARM processor. Processing times and localization accuracy are compared in both cases for single and double precision floating-point format. Experimental results show the advantages of the FPGA-based approach over the ARM-based approach. The proposed architecture can operate at 100 Hz and demonstrates the advantage of using FPGAs to design low-cost INS-GPS localization systems.

The ductility limits of an St14 steel are investigated using an elastic–plastic-damage model and bifurcation theory. An associative J2-flow theory of plasticity is coupled with damage within the framework of continuum damage mechanics. For strain localization prediction, the bifurcation analysis is adopted. Both the constitutive equations and the localization bifurcation criterion are implemented into the finite element code ABAQUS, within the framework of large strains and a fully three-dimensional formulation. The material parameters associated with the fully coupled elastic–plastic-damage model are calibrated based on experimental tensile tests together with an inverse identification procedure. The above-described approach allows the forming limit diagrams of the studied material to be determined, which are then compared with experimental measurements. A main conclusion of the current study is that the proposed approach is able to provide predictions that are in good agreement with experiments under the condition of accurate material parameter calibration. The latter requires a careful identification strategy based on both calibrated finite element simulations of tensile tests at large strains and appropriately selected necking measurements. The resulting approach represents a useful basis for setting up reliable ductility limit prediction tools as well as effective parameter identification strategies. Keywords: Ductile damage, Formability, Strain localization, Bifurcation analysis, Finite element simulation, Parameter identification

International audience; In this paper, a fully organic dual-band antenna is presented. It consists of a coplanar waveguide coupled to an elliptical monopole antenna designed on a kapton substrate. This antenna is fabricated from a process, based on the use of a conductive polymer (Polyaniline) doped with multiwall carbon nanotubes, that has been optimized for this application. The flexibility of both, kapton substrate and doped conductive polymer, gives the antenna the ability to be freely crumpled paving the way to body-worn high data rate communications at microwave frequencies. Applications in wireless networks can also be addressed by using this kind of antennas. In this study, a comparison between the performance of an antenna under bending conditions (using a 3D support) and its uncrumpled version is presented. We evaluate the crumpling effect on the resonant frequency, the bandwidth and the radiation patterns. A good agreement is observed between measurements and simulations data, even when the antenna is crumpled.

Now days, the ELM interferences prediction generated by converters, connected tothe network with respect to the EMC standards, is imperatively carried out using theLISN, which is not necessarily representative of the real network. Moreover, theEMC filters optimisation under LISN, may not guarantee automatically the correctoperation in a real network. Safety is then provided by means of excessive EMCmargins. The system is thus non‐optimal.The objective of this thesis is to progress in EMC modelling of converters andembedded networks, to be able to predict their EMC behaviour and to optimise theEMC filters., Aujourdʹhui la prédiction des perturbations conduites générées par lesconvertisseurs statiques connectés à un réseau, conformément aux normes CEM, estimpérativement réalisée sur RSIL, qui n’est pas forcément représentatif desimpédances des réseaux réels. D’autre part, l’optimisation des filtres CEM sur cettebase ne permet pas de garantir le bon fonctionnement de façon systématique sur unréseau réel. La sûreté est pourvue alors, au moyen de marges CEM souventexcessives. Le système est donc sous optimal.Lʹobjectif de cette thèse est de progresser dans la modélisation CEM desconvertisseurs et des réseaux embarqués, en vue de pouvoir prédire lecomportement CEM, et dʹoptimiser les moyens de filtrage.

In this paper, we treat the problem of trajectory planning of an unmanned ground vehicle evolving on an uneven terrain. In such environment, the role of the suspension system cannot be neglected and a vehicle vertical model has to be taken into account. In the present work, we present three reduced models with different level of complexity. These models make possible to handle the constraints inherent to stability, embedded equipment safety and suspension mechanical integrity. An optimization problem is also formulated in order to define the optimal speed profile for a safety behaviour of the mobile robot.

The rotational molding is a technique for implementation ofthermoplastic polymers. This process is subject of several studies in recent years. The purpose of our work is the thermal and chemical modeling of this process, taking into account the phase changes, in particular the crystallization and melting. These phasechanges were digitally processed for each polymer layer used in this study, using a method known as enthalpic then by another method derived from the crystallization kinetics. This method has been modified and adapted to our work by taking a coupling of two concepts: the first approach reflects the release of heat during processing of crystallinity; the second concept is the chemical modeling of the thermal degradation ofpolyamides., Le moulage par rotation est une technique de mise en oeuvre des polymères thermoplastiques. Ce procédé fait l'objet de plusieurs études durant cesdernières années. La finalité de notre travail est la modélisation thermique et chimique de ce procédé, tenant compte de la nature des polyamides, du changement de phases et en particulier la cristallisation et la fusion. Ces changements de phases ont été traités numériquement pour chaque couche de polymère, à l'aide d'une méthode dite enthalpique puis par une autre méthode dérivée de la cinétique de cristallisation. Cette dernière a été modifiée et adaptée à notre travail en procédant à un couplage de deux concepts ; le premier traduit le dégagement de la chaleur lors de la transformation dela cristallinité, le deuxième concept est la modélisation chimique de lathermodégradation des polyamides.

This paper introduces a new algorithm to approximate non orthogonal joint diagonalization (NOJD) of a set of complex matrices. This algorithm is based on the Frobenius norm formulation of the JD problem and takes advantage from combining Givens and Shear rotations to attempt the approximate joint diagonalization (JD). It represents a non trivial generalization of the JDi (Joint Diagonalization) algorithm (Souloumiac 2009) to the complex case. The JDi is first slightly modified then generalized to the CJDi (i.e. Complex JDi) using complex to real matrix transformation. Also, since several methods exist already in the literature, we propose herein a brief overview of existing NOJD algorithms then we provide an extensive comparative study to illustrate the effectiveness and stability of the CJDi w.r.t. various system parameters and application contexts., 13 pages, 18 figures

International audience; Many cereal straws have been used as raw materials for the preparation of microcrystalline cellulose (MCC). These raw materials were gradually replaced with wood products; nevertheless about 10% of the world overall pulp production is obtained from non-wood raw material. The main interest in pulp made from straw is that it provides excellent fibres for different industries with special properties, and that it is the major available source of fibrous raw material in some geographical areas. The aim of the present work was to characterize microcrystalline cellulose prepared from alfa fibers using the hydrolysis process. The products obtained are characterized with FTIR spectroscopy and X-ray powder diffraction. As a result, FTIR spectroscopy is an appropriate technique for studying changes occurred by any chemical treatment. The spectrum of alfa grass stems shows the presence of lignin and hemicelluloses. However, the cellulose spectrum indicates that the extraction of lignin and hemicellulose was effective. The X-ray analysis indicates that the microcrystalline cellulose is more crystalline than the source material.

International audience; The elastic modulus of thin films can be directly determined by instrumented indentation when the indenter penetration does not exceed a fraction of the film thickness, depending on the mechanical properties of both film and substrate. When it is not possible, application of models for separating the contribution of the substrate is necessary. In this work, the robustness of several models is analyzed in the case of the elastic modulus determination of a porous aluminium oxide film produced by anodization of an aluminium alloy. Instrumented indentation tests employing a Berkovich indenter were performed at a nanometric scale, which allowed a direct determination of the film elastic modulus, whose value was found to be approximately 11 GPa. However, at a micrometric scale the elastic modulus tends toward the value corresponding to the substrate, of approximately 73 GPa. The objective of the present work is to apply different models for testing their consistency over the complete set of indentation data obtained from both classical tests in microindentation and the continuous stiffness measurement mode in nanoindentation. This approach shows the continuity between the two scales of measurement thus allowing a better representation of the elastic modulus variation between two limits corresponding to the substrate and film elastic moduli. Gao's function proved to be the best to represent the elastic modulus variation.

International audience; This paper presents a method for fault prognostic of bearings based on Principal Component Analysis (PCA) and Support Vector Data Description (SVDD). The purpose of the paper is to transform the monitoring vibration signals into features that can be used to track the health condition of bearings and to estimate their remaining useful life. PCA is used to reduce the dimensionality of original vibration features by removing the redundant ones. SVDD is a pattern recognition method based on structural risk minimization principles. In this contribution, the SVDD is used to fit the trained data to a hypersphere such that its radius can be used as a health indicator. The proposed method is then applied on real bearing degradation performed on an accelerated life test. The experimental results show that the health indicator reflects the bearing's degradation.

This research work deals with two topics conditioning the large scale development of wind turbines into electrical grids. The first is devoted to the development of new algorithms for the control of Doubly Fed Induction Machine (DFIM) based wind energy conversion systems. Two direct current control strategies have been proposed and are based on the hysteresis square areas (HZCA) and hysteresis circular areas (HZCI). Both strategies apply an appropriate voltage vector to control the active and reactive powers delivered to the grid, and also, to balance the voltages of the inner DC bus converter. Simulation and experimental results show that the HZCI strategy is better than HZCA in terms of output voltage waveforms and harmonic contain.The second topic is dedicated to the active and reactive powers supervision in a wind farm in order to supply prescribed power references from the grid operator. This supervision is ensured by a centralized algorithm that distributes power references between wind turbines in a proportional way. These references are calculated according to the maximum production capacity of wind turbines. An analysis of the power flow in the DFIM based wind energy system has been made to identify the (P, Q) characteristic and to calculate limits in terms of reactive power compensation. The local power management of each wind system has been developed allowing the powers distribution between the stator of the DFIM and the grid side converter by considering several operating modes of the wind generator; La première thématique développée dans ce mémoire vise à développer de nouveaux algorithmes pour la commande des éoliennes reposant sur une machine asynchrone à double alimentation et des convertisseurs multi niveaux. Deux stratégies de contrôle direct du courant, basées sur l’Hystérésis à Zones Carrées et l’Hystérésis à Zones Circulaires (HZCi) ont été proposées. Celles-ci consistent à appliquer des vecteurs de tension appropriés pour contrôler les puissances actives et réactive générées et permettent également d’équilibrer les tensions du bus continu interne des convertisseurs. Des résultats de simulation et d’expérimentation montrent que la stratégie basée sur l’HZCi est meilleure en termes de forme d’onde et de contenu harmonique des tensions de sortie.La seconde concerne la supervision et la gestion des puissances active et réactive dans une ferme éolienne au vu de son intégration dans un réseau électrique. Cette supervision centralisée est assurée par un algorithme qui distribue les consignes de puissance aux éoliennes de la ferme de manière proportionnelle. Ces références sont fonction de la capacité maximale de production de l’éolienne. Pour cela, une analyse des transits de puissance dans le système éolien à base de la machine asynchrone à double alimentation a été effectuée. Elle a permis de déterminer la caractéristique (P, Q) du générateur et de calculer ses limites de compensation en termes de puissance réactive. Une gestion locale des puissances de chaque éolienne a été développée permettant ainsi une répartition des puissances entre le stator de la machine et le convertisseur coté réseau en considérant plusieurs modes de fonctionnement du système éolien

International audience; In multisensor tracking systems, the state fusion also known as track to track fusion is a crucial issue where the derivation of the best track combination is obtained according to a stochastic criteria in a minimum variance sense. Recently, sub-optimal weighted combination fusion algorithms involving matrices and scalars were developed. However, hence they only depend on the initial parameters of the system motion model and noise characteristics, these techniques are not robust against erroneous measures and unstable environment. To overcome this drawbacks, this work introduces a new approach to the optimal decentralized state fusion that copes with erroneous observations and system shortcomings. The simulations results show the effectiveness of the proposed approach. Moreover, the reduced complexity of the designed algorithm is well suited for real-time implementation.

International audience; An important challenge to any image pixels classification system is to correctly assign each pixel to its proper class without blurring edges delimiting neighboring regions. In this paper, we present an aerial image mapping approach that advantageously combines unsupervised segmentation with a supervised Markov model based recognition. The originality of the proposed system carries on three concepts: the introduction of an auto-adaptive circular-like window size while applying our stochastic classification to preserve region edges, the extension of the Dependency Tree-HMM to permit the computation of likelihood probability on windows of different shapes and sizes and a mechanism that checks the coherence of the indexing by integrating both segmentations results: from unsupervised over segmentation, regions are assigned to the predominating class with a focus on inner region pixels. To validate our approach, we achieved experiments on real world high resolution aerial images. The obtained results outperform those obtained by supervised classification alone.

International audience; We propose a new method for thermal rendering in telepresence systems which allows an operator to feel most transparently the thermal behavior of the remote object. It is based on learning and thermal heat flux generation. Two databases are constructed from real measurements recorded during direct contact between operator's finger and different materials. One database is used in order to identify the material in the slave side, the other database is used to generate desired heat flux for the thermal display loop. The identification bloc is based on Principal Component Analysis and Neural Network. Experimental results validating the proposed method are discussed.

In this article we address the problem of mobile robot formation control. Indeed, the most work, in this domain, have studied extensively classical control for keeping a formation of mobile robots. In this work, we design an FLC (Fuzzy logic Controller) controller for separation and bearing control (SBC). Indeed, the leader mobile robot is controlled to follow an arbitrary reference path, and the follower mobile robot use the FSBC (Fuzzy Separation and Bearing Control) to keep constant relative distance and constant angle to the leader robot. The efficiency and simplicity of this control law has been proven by simulation on different situation., {"references": ["", "Kar-Han Tan , M.A.Lewis, \u00d4\u00c7\u00ff-Virtual structures for high precision cooperative control--, technical report, Computer Science Department, University of California, Los Angles, 1997.", "W. Ren, R. W. Beard, \"A Decentralized scheme for spacecraft formation flying via the virtual structure approach\", AIAA Journal of Guidance, Control, & Dynamics, Revised Submission, June 2003.", "M. Egerstedt, K. Hu \u00d4\u00c7\u00ff-Formation constrained multi-agent control--, proceedings of 2001 IEEE International Conference on Robotics and Automation, pp .3961-3966, Seoul, Korea, May 21-26, 2001.", "J.M. Esposito, V. Kumar, \u00d4\u00c7\u00ff-A formalism for parallel composition of reactive and deliberative control objectives for mobile robots--, technical report, Mechanical Engineering and Applied Mechanics, University of Pennsylvania, Philadelphia, 2000.", "H.Yamgachi, \u00d4\u00c7\u00ff-A Cooperative Hunting Behavior by Mobile Robot Troops--, ICRA-98 pp.3204-3209, Leuven Belgium, May 1998", "K. Sugihara and I. Suzuki, \"Distributed algorithms for formation of geometric patterns with many mobile robots\", J. Robot. Syst., Vol. 9, pp.777-790, 2001.", "Jose Sanchez and Rafael Fierro, \u00d4\u00c7\u00ff-Sliding mode control for robot formations--, Proc. IEEE Int. Symposium on Intelligent Control, Oct. 2003, pp.438-443.", "Xiaohai Li, Jizong Xiao, Zijun Cai, \u00d4\u00c7\u00ff-Backstepping based multiple mobile robots formation control--, 2005 IEEE/RSJ International Conference on Intelligent Robots and Systems, pp.1313-1318.", "A. Luca, G. Oriolo and M. Vendittelli, ÔÇÿ-Control of wheeled mobile robots: An experimental overview--, in RAMSETE - Articulated and Mobile Robotics for Services and Technologies, S. Nicosia, B. Siciliano, A. Bicchi and P. Valigi, Eds. Springer-Verlag, 2001. [10] G. Oriolo, A. Luca and M. Vandittelli, ÔÇÿ-WMR control via dynamic feedback linearization: design, implementation, and experimental v validation--, IEEE Transactions on Control Systems Technology, vol. 10, no. 6, pp. 835-852, 2002. [11] G. Klan\u2500ìar, D Matko, S. Bla\u017ei\u2500ì, ÔÇÿ-Mobile robot control on a reference path--, Proceedings of the 13th Mediterranean Conference on Control and Automation Limassol, Cyprus, June 27-29, 2005, pp 1343-1348 [12] Y. Kanayama, Y. Kimura, F. Miyazaki, and T. Noguchi, “A stable tracking control scheme for an autonomous mobile robot," in Proceedings IEEE International Conference on Robotics and Automation, 1990, pp. 384-389. [13] S. G. Tzafestas and G. G. Rigatos, “A simple robust sliding-mode fuzzy logic controller of the diagonal type," J. Intelligent Robotic Systems, vol. 26, pp. 353-388, 1999. [14] Okyay Kaynak, Kemalettin Erbatur, and Meliksah Ertugrul, ÔÇÿ-The fusion of computationally intelligent methodologies and sliding-mode controlsurvey-- IEEE Transactions on Industrial Electronics, Vol. 48, No. 1, February 2001 pp. 4-17. [15] T.-H. S. Li and M.-Y. Shieh, “Switching-type fuzzy sliding mode control of a cart-pole system," Mechatronics, vol. 10, pp. 91-109, 2000."]}