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In order to slow down the continuing environmental deterioration, regulations for pollutant emissions limitations are increasingly rigorous. The development of new alternative fuels for internal combustion engines is a very interesting solution not only to overcome the pollution problem but also because of the petroleum shortage. In this context, the present work investigates the improvement of a DI diesel engine operating at constant speed (1500 rpm) and under dual fuel mode with eucalyptus biodiesel and natural gas (NG) enriched by various H2 quantities (15, 25 and 30 by v%). The eucalyptus biodiesel quantity injected into the engine cylinder is kept constant, to supply around 10% of the engine nominal power, for all examined engine loads. The engine load is further increased using only the gaseous fuel (NG+H2), which is introduced with the intake air. The effect of H2/NG blending ratio on the combustion parameters, performance and pollutant emissions of the engine is investigated and compared with those of pure NG case. An important benefit in terms of brake specific fuel consumption, reaching a decrease of 4–10% with the 25% H2 blend compared to the pure NG case, is achieved. Concerning the pollutant emissions, NG enrichment with H2 is an efficient solution to enhance the combustion process and hence reduce carbon monoxide, unburned hydrocarbon and soot emissions at high loads where they are important for pure NG. However for the nitrogen oxide emissions, NG blending with H2 is attractive only at low and medium loads where their levels are lower than pure NG.

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; An adaptive blind equalization algorithm for high-order quadrature amplitude modulations (QAM) is proposed. It is derived by combining the multi-modulus criterion and a new alphabet-matching penalty term. This penalty is based on the minimum L1-norm of the deviations of the equalizer output from the alphabet elements. Numerical experiments show that the proposed criterion provides higher performance in terms of residual error and convergence speed than the conventional multi-modulus algorithm (MMA) and its penalized versions.

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.

With the evolution of the communication technology, fast and efficient tools for secure exchanged data are highly required. Through this research work, we introduce a simplified and fast chaos-based scheme for multimedia data encryption and in particular for color image encryption application. The new algorithm is based on an extracted four-dimension (4-D) discrete time map. The proposed 4-D chaos system includes seven (07) nonlinear terms and four (04) controllers to generate a robust chaos that can satisfy the encryption requirements. The performance of this image encryption algorithm are analyzed with the help of four important factors which are key space, correlation, complexity and running time. Results of the security analysis compared to some of similar proposals, show that our encryption scheme is more effective in terms of key stream cipher space, correlation, complexity and running time.

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.

International audience; Several proposals of chaos-based algorithms have been proposed for secure communication and image encryption. In this paper, a new algorithm for colour image encryption has been proposed. The algorithm is based on a new 3-dimensional (3-D) discrete time chaos system which performs the diffusion and confusion processes. The novelty of the proposed work is the new 3-D map defined by five nonlinear terms and three control parameters to ensure better chaotic properties. Moreover, the proposed new map is used to perform 3-stage encryption algorithm which achieves better performance while preserving the traditional confusion-diffusion structure. Security analysis of the proposed algorithm is investigated and compared to some existing methods in terms of key space, metric entropy and correlation. Simulated results of our encryption algorithm prove its performance and suitability for colour image encryption

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

The heterogeneity and complexity of lignin necessitate a deep understanding to select the most appropriate lignin valorization and convert it into value-added products. The objective of this research is to investigate the features of organosolv and Kraft lignins, in order to understand the effects of the sources and the isolation treatment, through the comparison of physicochemical and thermal properties. Various techniques have been employed such us Fourier transform infrared spectroscopy (FTIR), carbon solid state nuclear magnetic resonance 13CNMR, scanning electron microscopy, thermogravimetric analysis, and differential scanning calorimetry. It was found that lignin produced from the hardwood using the Kraft process provided the greatest yield compared to other combinations. Softwood pretreatments achieve almost higher sugar yield than hardwood treatments. The infrared spectroscopy analysis confirms the existence of different monolignols. Organosolv lignins showed a predominance of guaiacyl and syringyl units. To provide additional information, the principle components analysis, as a powerful chemometric method, has also been applied to evaluate the FTIR data. NMR spectroscopy of lignins demonstrated the presence of essential functional chemical groups. It is also revealed that the nature of the treatment and the source of lignin samples affect the thermal properties. Overall, lignin isolated from Aleppo pine using Kraft process presented better thermal stability than that of organosolv lignin.

Three-dimensional direct numerical simulations are used to characterize turbulent buoy-ant convection in a box-shaped Rayleigh Bénard cavity with a rough bottom plate madeof a series of square based blocks separated by valleys. The cavity is filled with water, andthe Rayleigh number varies over five decades up to 10 10 . As mentioned in the literature,three successive heat transfer regimes are identified: from inactive roughness (I) to aregime (III) where the heat transfer increase is larger than the one expected from theonly roughness induced surface increase. The heat transfers of the transitional regime IIare particularly intense. After validation against experimental and numerical data fromliterature, we highlight the role of the inner fluid trapped within valleys. It is shown thatthe heat transfer through the fluid interface between the cavity bulk and the inner fluidis strongly related to the overall heat transfer at the rough plate, with an exponent ofthe heat transfer scaling law close to 1/2 in the regime II. We found that this regimeis active when the thermal boundary layer is thinner than the roughness height and, atthe same time, the kinetic boundary layer is larger. As compared to regimes I and III,regime II is characterized by larger temperature fluctuations, especially near the roughplate, and a larger friction coefficient. A fluctuating rough layer overlaying both blocksand valleys appears in the regime III, in addition to the classical boundary layers formedalong the plate topography.

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.

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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.

International audience; Additive manufacturing (AM) technology has been identified as one of the major digital innovations that has revolutionized not only the field of the industry but also the construction. From a research side, AM is a multi-disciplinary domain, combining between materials science, mechatronics engineering and architectural design. The AM concept needs to consider the geometry and the shape of printed objects in regards of material properties and robot kinematics which are adaptable to the object size. In this paper, we present an integrated design and control of an omnidirectional Mobile Manipulator Robot (MMR), capable of extruding concrete and clay materials, to print complex and funicular architectural geometries. The studied robot allows printing building pieces with different shapes and sizes by additive deposit which can later be assembled on-site. The main issue concerns the control of continuous material deposit, with specified accuracy and respecting the desired shape. This problem involves to solve, in real-time, the non-linear kinematic model of a 10 Degrees of Freedom (DoF) heterogeneous robot. The kinematic model and the control of utilized MMR are discussed, and an optimization method based on quadratic programming is used for handling the robot redundancy. Finally, we present the experimental results to illustrate the efficiency of AM on the developed concept.

The aim of this thesis is to propose an interactive design and optimization approach toimprove the preliminary design of product. This approach offers a set of tools to assistdesigners to make decisions without intensive expert inquiries. It consists in splittingthe preliminary design phase into two levels of design and optimization. In the firstlevel, the design process is based on a reduced (analytical) model of the product, whichis integrated in an appropriate optimization procedure to select best design solutions.The second level is based on the use of a fine (numerical) model of the consideredproduct to improve the design around a solution selected from results of the first level.The proposed approach is tested on a redesign case of a mechanical product. Throughtwo case study, the use of this approach leads to a significant improvement of theproduct design and the satisfaction of desired objectives in terms of performances. Theobtained results highlighted the efficiency of the proposed approach and open newperspectives for future research activities in the field of design process enhancement.; L’objectif de cette thèse est de proposer une approche de conception et d’optimisationinteractive afin d’améliorer la conception préliminaire d’un produit. Cette approcheoffre des outils d’aide à la prise de décision aux concepteurs pour mener à bien laconception préliminaire sans solliciter les experts d’une façon intensive. Cette approcheconsiste à structurer la phase de conception préliminaire en deux niveaux. Le premierniveau repose sur l’utilisation d’un modèle simplifié (analytique) du produit considéréet rechercher les solutions de conception associées. Le deuxième niveau de conceptionet d’optimisation repose sur l’utilisation d’un modèle fin (numérique) du produit pouraméliorer la conception autour de la conception retenue durant le premier niveau.L’approche proposée est testée sur un cas de conception routinière d’un produitmécanique. Suite à deux cas test, l’utilisation de cette approche a permis uneamélioration significative de la conception et des performances du produit. Les résultatsobtenus démontrent l’efficacité de l’approche proposée et ouvrent de nouvelles voies derecherche dans le domaine de l’amélioration du processus de conception.

The aim of this thesis is to propose an interactive design and optimization approach toimprove the preliminary design of product. This approach offers a set of tools to assistdesigners to make decisions without intensive expert inquiries. It consists in splittingthe preliminary design phase into two levels of design and optimization. In the firstlevel, the design process is based on a reduced (analytical) model of the product, whichis integrated in an appropriate optimization procedure to select best design solutions.The second level is based on the use of a fine (numerical) model of the consideredproduct to improve the design around a solution selected from results of the first level.The proposed approach is tested on a redesign case of a mechanical product. Throughtwo case study, the use of this approach leads to a significant improvement of theproduct design and the satisfaction of desired objectives in terms of performances. Theobtained results highlighted the efficiency of the proposed approach and open newperspectives for future research activities in the field of design process enhancement.; L’objectif de cette thèse est de proposer une approche de conception et d’optimisationinteractive afin d’améliorer la conception préliminaire d’un produit. Cette approcheoffre des outils d’aide à la prise de décision aux concepteurs pour mener à bien laconception préliminaire sans solliciter les experts d’une façon intensive. Cette approcheconsiste à structurer la phase de conception préliminaire en deux niveaux. Le premierniveau repose sur l’utilisation d’un modèle simplifié (analytique) du produit considéréet rechercher les solutions de conception associées. Le deuxième niveau de conceptionet d’optimisation repose sur l’utilisation d’un modèle fin (numérique) du produit pouraméliorer la conception autour de la conception retenue durant le premier niveau.L’approche proposée est testée sur un cas de conception routinière d’un produitmécanique. Suite à deux cas test, l’utilisation de cette approche a permis uneamélioration significative de la conception et des performances du produit. Les résultatsobtenus démontrent l’efficacité de l’approche proposée et ouvrent de nouvelles voies derecherche dans le domaine de l’amélioration du processus de conception.

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; Prostate Cancer is one of the most prevalent cancers in men and a leading cause of death. Prostate Brachytherapy (BT) is one of the promising treatment techniques. The use of BT techniques is made easier, thanks to the developments of associated imaging technologies like Ultrasound and Magnetic Resonance Imaging (MRI). MRI has the capacity to detect small lesions providing a wider scope of research and enabling better accuracy in BT treatments. In order to enhance the diagnosis of prostate cancer and its treatment options in the 2 seas region, Europe, Interreg 2 Seas co-financed a European Union Project Cooperative Brachytherapy called CoBra. The aim of the CoBra project is to perform a robotized biopsy and BT under real-time MRI-guidance. The concept is under development, such as the robot's task should be achieved within the MRI-scanner without any repositioning of the patient.

International audience; In network communication domain, one of the most widely used protocol for encrypting data and securing communications is the IPSec protocol. The design of this protocol is based on two main phases which are: exchanging keys phase and transferring data phase. In this paper we focus on enhancing the exchanging keys phase which is included in the security association (SA), using a chaotic cryptosystem. Initially IPSec is based on the Internet Key Exchange (IKE) protocol for establishing the SA. Actually IKE protocol is in charge for negotiating the connection and for authenticating both nodes. However; using IKE gives rise to a major problem related to security attack such as the Man in the Middle Attack. In this paper, we propose a chaotic cryptosystem solution to generate SA file for the connected nodes of the network. By solving a 4-Dimension chaotic system, a SA file that includes 128-bit keys will be established. The proposed solution is implemented and tested using FPGA boards.

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.

International audience; Over the last decades, Field Programmable Gate Array (FPGA) boards have seen their use widely spread in different research topics. This can be explained by their low power consumption, their ability of enhancing the performances, and the several functions that can be included in those circuits. One major function delivered by FPGA boards is to be reconfigurable which helps during the development and validation stages, since it is always possible to correct just the program and to reload it in the circuit. Using these advantages and functions was the main idea of our work. In this paper, we will show how to design and to implement a Pseudorandom-Key-Generator that can be used to secure a socket-based communication. The proposed key-generator, created by solving the Lorenz chaos-system, has the main task of delivering at each opened channel a new 32-bit key that is used for encrypting/decrypting data. The proposed approach is implemented and tested using Xilinx Zync702 Boards.

Environmental benefits are one of the main motivations encouraging the use of natural gas as fuel for internal combustion engines. In addition to the better impact on pollution, natural gas is available in many areas. In this context, the present work investigates the effect of hydrogen addition to natural gas in dual fuel mode, on combustion characteristics improvement, in relation with engine performance. Various hydrogen fractions (10, 20 and 30 by v%) are examined. Results showed that natural gas enrichment with hydrogen leads in general to an improved gaseous fuel combustion, which corresponds to an enhanced heat release rate during gaseous fuel premixed phase, resulting in an increase in the in-cylinder peak pressure, especially at high engine load (4.1 bar at 70% load). The highest cumulative and rate of heat release correspond to 10% Hydrogen addition. The combustion duration of gaseous fuel combustion phase is reduced for all hydrogen blends. Moreover, this technique resulted in better combustion stability. For all hydrogen test blends, COVIMEP does not exceed 10%. However, no major effect on combustion noise was noticed and the ignition delay was not affected significantly. Regarding performance, an important improvement in energy conversion was obtained with almost all hydrogen blends as a result of improved gaseous fuel combustion. A maximum thermal efficiency of 32.5%, almost similar to the one under diesel operation, and a minimum fuel consumption of 236 g/kWh, are achieved with 10% hydrogen enrichment at 70% engine load.

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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.

International audience; In this work, simultaneous transesterification and thermochemical liquefaction of Pistacia Atlantica, an oleaginous plant, using ethanol as a reagent and a solvent was studied. Experiments were performed under temperatures ranging from 300 to 450°C and pressures ranging from 40 to 85 bar. Effects of temperature and pressure on conversion rate, bio-oil and gas yield were studied. The maximum conversion rate and bio-oil yield were 82% and 56% respectively and were obtained at 375°C and 43 bar. Gaseous products were mainly composed of carbon oxides at low temperatures. At 450°C the percentage of light hydrocarbons increased to more than 40% due to secondary cracking of bio-oil. Bio-oil was compared to conventional biodiesel and it was concluded that products have higher viscosity and oxygen to carbon ratios and lower hydrogen content and heating values. Products obtained at 300°C and 46 bar recorded the lowest viscosity that reached 6.8 mPa.s.

Experimental data of thermodynamic properties of mixtures used in the composition of new fuel generations are very rare in the literature.The aim of this thesis is to contribute to setting up a thermophysical database of constituents used in the composition of biodiesel / diesel mixtures over a wide range of pressure and temperature (1 Pa to 200 kPa).Thanks to the static apparatus available in the laboratory (UMR 5615-Lyon1) and to the various methodologies developed to determine phase equilibrium, the acquisition of reliable data has been obtained for 8 pure substances and their binary mixtures. The vapor pressures of the pure compounds are in good agreement with the literature data in the range above 1 kPa whereas no data has been found to compare with experimental values of the pure compounds or mixtures below 1 kPa.A good correlation of the experimental results was obtained using two thermodynamic models, NRTL and UNIQUAC.The study of the volumetric properties obtained by densimetry, led us to interpret the different interactions that could exist in a binary mixture consisting of ester and alkane and to estimate quantitatively the different contributions to the excess molar volume; Les données expérimentales sur les propriétés thermodynamiques des mélanges entrant dans la composition des nouvelles générations de carburants sont rares ou entachées d’erreur. L’objectif de cette thèse est de contribuer à l’alimentation de base de données thermophysique de corps purs et de mélanges entrant dans la composition des carburants formés de biodiesel/diesel dans une large gamme de pression et de température (1 Pa à 200 kPa). Grâce à l’appareil statique disponible au laboratoire (UMR 5615) et aux différentes méthodologies mises au point pour la détermination des équilibres de phase, l’acquisition de données fiables a été obtenue pour 8 corps purs et leurs mélanges binaires. Les valeurs relatives aux pressions de vapeur des corps purs sont en bon accord avec la littérature dans le domaine des pressions moyennes. En revanche pour les faibles pressions de vapeur (inférieures à 1 kPa) et pour les mélanges binaires étudiés, les pressions de vapeur obtenues sont originales. Les deux modèles thermodynamiques NRTL et UNIQUAC ont restitué les résultats expérimentaux de façon satisfaisante.L’étude des propriétés volumétriques par la mesure de la densité, nous a permis d’interpréter les différentes interactions qui peuvent exister dans un mélange binaire constitué d’un ester et d’un alcane

The aim of the present work is to predict the occurrence of plastic instabilities (diffuse and localized necking) in thin sheet metals. The prediction of these plastic instabilities is undertaken using an elastic–plastic model coupled with ductile damage, which is then combined with various plastic instability criteria theory. The bifurcation-based criteria and the maximum force criterion used in this work are formulated within a general three-dimensional modeling framework, and then applied for the particular case of plane-stress conditions for sheet metals. Some theoretical relationships or links between the different investigated necking criteria are established, which allows a hierarchical classification in terms of their conservative character in predicting critical necking strains. The resulting numerical tool is implemented into the finite element code ABAQUS/Standard to predict forming limit diagrams, in both situations of a fully three-dimensional formulation and a plane-stress framework. This approach, that combines constitutive equations to necking criteria, serves as a useful tool in the design of new materials with improved ductility; L’objectif de ce sujet de thèse est de prédire l’apparition des instabilités plastiques (striction diffuse et striction localisée) dans les matériaux métalliques. Ces matériaux sont décrits par des modèles de comportement élasto-plastique couplés à l’endommagement. L'approche de Lemaitre, reliant l'endommagement à la déformation plastique équivalente et au taux de restitution de la densité d'énergie élastique, est adoptée. Parmi les différents critères et indicateurs qui sont considérés pour la prédiction des instabilités matériau, la théorie de bifurcation et les critères de type force maximum sont tout particulièrement analysés et comparés. Un objectif important de cette étude consiste à déterminer les mécanismes déstabilisants clés associés à cette modélisation du comportement, ainsi que l’impact des différents aspects physiques et des paramètres matériau sur l’apparition de la striction. Les développements résultants sont appliqués à une sélection représentative de matériaux métalliques afin prédire leurs limites de formabilités. Cette approche combinant des lois de comportement et critères de striction peut être utilisée comme outil théorique et numérique d’aide à la conception de nouveaux matériaux à ductilité améliorée

International audience; In the near future, unmanned aerial vehicles, are probably going to be integrated in the airspace and the current air traffic management concepts, need to be reviewed. Enhancements are expected from reliability, safety, and accuracy point of view. Adaptive flight control could support partially such challenge, regarding its capability to face modelling inaccuracies, parameter uncertainties and external disturbances. In addition, it could improve both of the flying and handling qualities, and impacts positively stability and maneuvrability margins, especially in the presence of unfavorable flight conditions. The main objective of this paper deals with a quadcopter adaptive flight control system that generates the necessary control laws to perform accurately, as well as possible, the reference flight trajectories. In this paper, a direct dynamical adaptive flight controller, based on backstepping approach, is developed for quadcopter trajectory tracking, where minimum phase and observability conditions are checked from differential geometry point of view. Developed direct adaptive backstepping flight control system provides nonlinear adaptive control laws in an iterative and systematic procedure design. Therefore, interlaced tuning functions are used to estimate and update laws in order to compensate the uncertain parameters of interest. The global stability of the proposed adaptive flight control system is guaranteed, based on Lyapunov theory, where the design of adaptation laws according to some quadcopter parameters is developed. Numerical simulations are performed for the quadcopter, engaged in complex trajectory tracking, and obtained results show the feasibility and effectiveness of the proposed adaptive flight control approach.

In the present paper, a new joint eigenvalue decomposition (JEVD) method is developed by considering generalized Givens rotations. This method deals with a set of square matrices sharing a same eigenstructure. Several Jacobi-like methods exist already for solving the aforementioned problem. The differences reside in the way of estimating the Shear rotation. Herein, we clarify these differences, highlight the weaknesses of the existing solutions and develop a new robust method named Efficient and Stable Joint eigenvalue Decomposition (ESJD). Simulation results are provided to highlight the effectiveness of the proposed technique especially in difficult scenario.

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; Building context-aware pervasive computing systems - such as ambient intelligent spaces or ubiquitous robots - needs to take into account the quality of contextual information collected from sensors. Such information are often inaccurate, uncertain or subject to noise due to environment and user dynamics. Dempster-Shafer theory has been extensively adopted to handle uncertainty in situation and activity recognition. This theory is used to represent, manipulate and decide under uncertainty. However, combining information using Dempster's rule may produce counterintuitive decision in highly conflicting evidences due to sources failure. Recently, a variety of rules were proposed to overcome such drawback. Inspired by Murphy's rule, we propose in this paper a new rule called “Weighted Average Combination Rule” (WACR) to deal with context recognition in highly dynamic environment such as ambient intelligence spaces. The proposed WACR rule is based on evidence arithmetic average and cardinality. WACR rule was applied to some conflictual evidence examples and has been shown to reap more appropriate decisions than other alternative rules for decision-making in activity-aware systems. To demonstrate the applicability and performance of our approach, we have studied a scenario of context recognition in an ambient intelligent environment. In this scenario, we simulated a smart kitchen composed of status devices and RFID sensors that allow determining what is the artifact in use by the inhabitant and for which activity.

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; This paper deals with the estimation of power consumption for an unmanned road vehicle, according to the degree of steerability, the degree of redundancy and the path curvature changes. Thus, the main dynamic behaviors inducing directly or indirectly the power consumption for an autonomous road vehicle are considered for uniform and uniformly variable motions less than 15km/h. A comparison between different scenarios of piloting has been validated experimentally and through co-simulation using professional real-time dynamic vehicle simulator namely SCANeR Studio(c).

A novel spectral-based feature set is proposed for ground moving target classification using a battlefield surveillance radar. Precise frequencies and coefficients are extracted from the backscattered radar signal which is used as an information in Automatic Target Recognition (ATR) system to solve the problem of ground moving target classification. The proposed ATR system is realized by combining Gaussian Mixture Model (GMM) with Maximum Likelihood (ML) rule. Experimental signals, realized with ground surveillance radar operating in centimetre range wavelengths, are used to test our ATR system. Numerical evaluation results are presented to assess the performance gain provided by the proposed method.

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.

International audience; In recent years, a plethora of different studies for design of traditional ensemble classifiers has been proposed in order to improve final recognition accuracy. However, among the ensemble classifiers, combination methods are focused on building independent classifiers of the same or different algorithms using majority voting methods. In this paper, we present a new fusion scheme for ensemble classifiers based on a new concept called Generalized Fuzzy Soft Set (GFSS), which we apply in activity classification. Essentially, we apply a weighted aggregate operator to the output of each classifier in order to fuse the GFSS into a more reliable classifier. The proposed fusion method is based on a new ranking algorithm to classify activities. We show that the proposed method produces more accurate results than the best single classifier and its effectiveness is demonstrated by comparing it with single classifier in terms of activity recognition accuracy.