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International audience

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International audience; Are Computer Supported Cooperative Work in Design (CSCWD) media worth to be used or do we need to maintain the traditional paper-based ones? Several studies exist, but address heterogeneous functions and criteria, and are not comparable. This contribution introduces an exploratory study toward a Unified Paradigm of evaluation (UP). UP aims to ease the setup of comparable design studies to evaluate if CSCWD are worth to be used in respect of actual supports. The most adapted paradigm to provide a valuable answer prescribes ethnographic qualitative descriptive studies between a traditional paper-based and a CSCWD media. A scenario centered on a common function is presented (isofunctional comparison). The criterion assessed is effectiveness, expressed as the combination of efficacy and usefulness. Efficacy is measurable through objective factors. Usefulness is measurable through subjective factors. In order to confront studies involving different people, we suggest that individual characteristics should be properly considered.

International audience

International audience; The paper proposes experimental flexible moulds usable in the bakery sector. Based on principles derived of origami techniques, a square baking paper sheet becomes a structured baking paper moulds (CBPM) able to reproduce structures inspired by nature. Some prototypes are presented to prove their operational ability to achieve the same functions as existing silicone moulds. In a sustainable context, they also have the advantages to be based on agro-resources, recyclable and biodegradable, they can be considered as eco-friendly products.

International audience; Flexible packages are considered as the most-reduced form of packaging in terms of environmental performances. In order to contribute to their development, this paper proposes to explore some mechanical properties brought by a new folding process that confers elasticity to flexible materials and consequently new environmental advantages. The innovative folding process consists in sequences of crumpling actions transforming a 2D sheet into a dynamic 3D flexible structure, without cutting or gluing actions. In order to prove the efficiency of the crumpling process, a methodology is proposed to evaluate the ability of a material to be crumpled. The procedure is then applied on different types of papers used in the food industry, and a study case of a crumpled packaging highlights new innovative functionalities as well as its potential environmental gain.

International audience

International audience

International audience

International audience

This work is the continuation of a ‘revolution’ started with "Research Counts, Not the Journal". Own and published opinions from worldwide scientists on critical issues of peer-reviewed publishing are presented. In my opinion, peer-reviewed publishing is a quite flawed process (in many ways) that has greatly harmed Science for a long time – it has been imposed by most academic and science funding institutions as the only way to assess scientific performance. Unfortunately, most academics still follow that path, even though I believe most do it for the fear of losing their job or not being promoted. This paper aims to encourage (i) a full disruption of peer-reviewed publishing and (ii) the use of free eprint repositories for a sustainable academic/scientific publishing, i.e. healthier (no stress/distress associated to the peer review stage and the long waiting for publication) and more economic, effective and efficient (research is made immediately available and trackable/citable to anyone). On the other hand, it should be pointed out that nothing exists against scientific publishers/journals – actually it´s perfectly normal that any company wants to implement its own quality criteria. This paper is just the way chosen to promote the quick implementation of suitable policies for research evaluation.

Treatment efficiency of the sewage stabilization ponds at Chokera, Faisalabad was carried out with respect to the parameters (i.e. BOD5 (Five Days Biochemical Oxygen Demand), COD (Chemical Oxygen Demand), pH, Turbidity, TS (Total Solids), TDS (Total Dissolved Solids), Copper, Lead, etc.). Parameters under investigation were monitored at six different locations (i.e. Influent of treatment plant, Influent of anaerobic Ponds, Effluent of Anaerobic Ponds, Effluent of Facultative Ponds, Drain before disposal of treated sewage and Drain after mixing with treated sewage). The testing was done during the low flow season i.e. from December 2015 to January 2016 in Environmental Engineering Laboratory, Department of Civil Engineering, The University of Lahore, Pakistan. BOD5 removal efficiency of the treatment plant was found 30.08 against designed value of 90% removal. The removal efficiency of COD, TS, TDS, pH, Turbidity, lead and Copper was found 36.56, 22.43, 30.40, 3.43, 73.50, 34.13 and 41.15%, respectively. The maximum removal was of turbidity which is 73.50% but still none of the parameters of the effluent were meeting the PEQS (Punjab Environmental Quality Standards) 2012 except pH and TS. The reasons of low efficiency included lack of funds by government for operation and maintenance of the ponds, increased population, mixing of industrial sewage with domestic and less attention to maintain the performance of Ponds.

International audience; We present the effects of using a single-pixel camera approach to extract optical properties with the single-snapshot spatial frequency-domain imaging method. We acquired images of a human hand for spatial frequencies ranging from 0.1 to 0.4 mm - 1 with increasing compression ratios using adaptive basis scan wavelet prediction strategy. In summary, our findings indicate that the extracted optical properties remained usable up to 99% of compression rate at a spatial frequency of 0.2 mm - 1 with errors of 5% in reduced scattering and 10% in absorption.

Torrefaction is a pre-treatment process which can improve the properties of biomass, such as improving grindability, increasing heating value, and reducing the hygroscopic nature. Potassium is a well-known alkali catalyst in the thermal reactions of biomass. The influence of potassium on the devolatilization behavior was dependent on the amount of loading potassium. The aim of this study is to figure out the effect of potassium on the thermal degradation of biomass, the rubber wood sawdust was adopted as the feedstock, and the biomass sample was crushed and then dried in an atmospheric oven. Impregnation was used to prepare samples with different potassium ion content equably and adequately. Thereafter, the sample was torrefied by in a thermogravimetric analyser (TG) at different temperature (150, 20, 250, and 300 °C). The experimental results show that the addition potassium can significantly change the chemical kinetics, and further enhanced the thermal degradation of biomass during torrefaction.

International audience; The thermal and mechanical properties of cellulose fibre insulation, installed via the wet spray projection method, were studied. The isotherms of loose fibres were determined using dynamic vapour sorption to study their behaviour with water. Wet spray cellulose samples with varying water dosage were subjected to compression, and thermal conductivity testing. Results showed density, modulus of elasticity, and thermal conductivity all increased with water dosage. These factors are to be considered for when applying wet-spray cellulose fibre insulation to ensure the properties of the material are consistent.

The exceptional natural durability of Prosopis africana heartwood was investigated to find potential new biocides for wood preservation. Extractions carried out with different solvents indicated high levels of extractives which explained wood durability towards fungal and insects attacks. However, the extractives were not enough to explain the durability. The hydrophobic character of the wood also likely had a significant effect. Contact angle measurements before and after extraction, indicated that extractives have only a minor effect on wood hydrophobicity. Microscopic analysis reveals the presence of high levels of gums filling the wood cell lumens, limiting the penetration of water.

International audience; This paper presents a novel verification methodfor arithmetic circuits subjected to some user or applicationconstraints. The verification problem is solved in an algebraicdomain rather than in a Boolean domain by representingcircuit specification and its implementation as polynomials.The concept of deterministic terms is introduced to describethe constraints imposed on the circuit. Based on this concept, acase splitting analysis is proposed to resolve the memory problemduring algebraic rewriting. The computational complexityof the method is analyzed, and two techniques are proposedto accelerate the verification process. The experimental resultsfor constrained arithmetic circuits up to 128 bits, and thecomparison with the state-of-the-art SAT solver demonstratethe effectiveness and the scalability of the proposed method.

International audience; Development of new network standards leads to use bulky base station antennas. Their widesurfaces are not compatible with integration constraints in urban areas. As the antenna is composed ofa high number of radiating elements, reduce the surface of each element is a way to reduce the antennasurface. Compact radiating element would allow several antennas integration on the initial surface. Inthis paper, a new compact antenna is designed in order to obtain up to four antennas at the place ofone. The antenna gain and horizontal Half Power Beamwidth (HPBW) should be maintained. The sizereduction is obtained by dielectric embedding. In order to determine the dielectric characteristics inwhich the antenna must be immersed, a theoretical model is proposed in this paper. Simulations andmeasurements are provided to show the evolution of the antenna's performances in order to achievemanufacturer's specifications.

This paper presents the experimental investigations conducted on the carillon tower of the Santissimo Crocifisso Sanctuary in Castel San Pietro (Bologna, Italy) and the analysis of data collected by using velocimeters and accelerometers installed on the structure. The main goal is to assess the effects of the swinging bells on the dynamic behaviour of the tower. The paper’s novelty relies on the kind of structure monitored and the originality of the experiments. The structure is a rare example of a carillon tower, with fifty-five bells of different sizes, subjected to a careful measurement campaign never carried out before. Six experiments were conducted selectively by activating the bells to measure the tower’s response induced by different vibration sources and determine the peak velocities recorded by using instruments at different heights. Two ambient vibration tests complemented the six experiments. The carillon’s action induces low velocities on the tower, while experiments involving the bells swinging in the upper chamber produce the highest velocity values in the swinging direction; these values are more significant than those induced by the carillon alone. The most robust action is induced on the tower when all the bells (carillon plus swinging bells) ring. The experimental results are complemented by numerical simulations of the dynamic behaviour of the tower subjected to the action of a swinging bell.

The objective of this paper is to discuss the problem of maintenance modelling and optimisation for a deteriorating Photo- voltaic panel system. In this paper, we model the dust accumulation process as PV panels’ as the main degradation cause considering the wind conditions as covariates. The dust accumulation process is mod- eled by a non-homogeneous compound Poisson process (NHCPP). The covariates process is assumed to be a time-homogenous Markov chain with finite state space. A model similar to the proportional hazards model is used to show the influence of covariates on the degradation process. In the framework of the system under consideration, an appropriate maintenance policy which minimises the long run average maintenance cost and maximises the long run average profits is derived. Numerical implementations are presented to illustrate the performance of the proposed model.

International audience; The high-dimensional and multiscale nature of fusion plasma flows require the development of reduced models to be implemented in numerical codes capable of capturing the main features of turbulent transport in a sufficiently short time to be useful during tokamak operation. This paper goes further in the analysis of the dynamics of the κ − ε model based on the turbulent kinetic energy κ and its dissipation rate ε [Baschetti et al., Nuc. Fus 61, 106020 (2021)] to improve the predictability of the transverse turbulent transport in simulation codes. Present 1D results show further capabilities with respect to current models (based on constant effective perpendicular diffusion) and on the standard quasi-linear approach. The nonlinear dependence of D in κ and ε estimated from two additional transport equations allow to introduce some non-locality in the transport model. This is illustrated by the existence of parameter ranges with turbulence spreading. The paper also addresses another issue related to the uncertainties on the inherent free parameters of such reduced model. The study proposes a new approach in the fusion community based on a variational data assimilation involving the minimisation of a cost function defined as the distance between the reference data and the calculated values. The results are good, and show the ability of the data assimilation to reduce uncertainties on the free parameters, which remains a critical point to ensure the total reliability of such an approach.

International audience; Industrial Control Systems (ICS) are increasingly deployed in critical infrastructures. Originally designed to increase the productivity of ICS as well as safety and reliability, nowadays these systems are becoming the target of hackers. Several attacks highlighted vulnerabilities, the most relevant one, Stuxnet, stroke in 2010. Protection of ICS against cyberattacks has to be considered. Security of these systems is different from IT security solutions because exchanged data have physical consequences. For that, a new approach for Intrusion Detection System (IDS) in ICS was presented based on filters monitoring orders and reports. Methodology to obtain these filters and their locations in the ICS architecture were introduced. In this paper, we present major improvements in detection mechanisms of these filters. Distance concept, introduced in previous paper (Sicard et al., 2017), is developed and combined to trajectory concept that allows filters to detect deviations from expected behavior. Distance from optimal or forbidden states is essential to compute order sequence bringing back the system into safe states. Trajectory, which is the evolution of distance during state evolution, improves detection mechanism by analyzing sequences sent to the system and received by Programmable Logic Controller (PLC). This combinational security prevents damages against goods and people. Implementation of time based intrusion detection is a step forward for improving filters. Temporal windows indicate when actions have to be done and if received reports correspond to executed orders. Thus, our filter approach secures ICS against combinational and temporal attacks affecting security of goods and people or quality.

This paper introduces the special topic forum (STF) on purchasing and innovation. Presenting the findings from a systematic literature review, we take stock of the current state of the field, delineating themes, theories and methods, and identifying key trends over time. Our study shows a take-off in research on purchasing and innovation during the last decade. This has predominantly focused on private sector manufacturing firms although a recent expansion into public sector research is evident. Large-scale surveys and case studies are still the dominant research methods where the unit of analysis is typically the ‘firm’ or ‘project’. The findings also show how in the past the field was driven by questions on how purchasing can facilitate different types of innovation projects, seeking to derive practical implications, and rarely making explicit statements regarding theories applied; this still characterises much of the research but we find an increasing focus on theory development. We also see a shift in the type of technological innovation being investigated: past studies tended to focus on the role of purchasing in new product development (NPD) projects, which reflected a relatively low degree of technological uncertainty, but we see a trend towards innovation projects facing technological uncertainty. Research shows how this requires new ways of sourcing innovations and therefore new ways for purchasing to facilitate innovation sourcing. On the basis of the review, we offer our guidance for future research avenues to 1) carry out more research on procurement of innovation in the public sector; 2) consider new theories and research methods, and 3) go beyond firm-level or dyadic analysis to research networks and ecosystems. We conclude by introducing the papers in the STF.

Artificial Intelligence (AI) is becoming a key technology for space applications. Recently, AI has come into extensive use in spacecraft operations, for example to support highly efficient operations of satellite constellations. This ranges in applications from relative positioning, Earth Observation, autonomous navigation, and end-of-life management, among others. While the importance of AI is rising for new space assets, AI is vulnerable to cyber threats, and AI cyber security is becoming an important aspect of space safety and operational security. This work aims to identify the vulnerabilities that AI systems may introduce to space assets and to analyse the potential operational threats and effective technological and regulatory mitigation measures. Towards this goal, the paper first examines and differentiates between vulnerabilities in legacy space systems, and those that are particularly related to AI technologies. The analysis covers the definition of AI technology as well as a detailed discussion about its current use in space related applications. Secondly, a comparison between prevailing cyber-attacks in space and cyber-attacks targeting AI technologies is made. Based on this assessment, the paper recommends prevention and mitigation measures that are contingent on cyber resilience of space operations focusing on AI-based space applications.

This paper aims at summarizing the recent aerodynamic design activities performed at ONERA on promising innovative aircraft and engine integration concepts with the objective to strongly reduce Aviation's climate impact. Within different projects of the Clean Sky 2 European Programme, ONERA explores two specific aircraft configurations combined with two innovative engine integration technologies for a typical Small Medium Range (SMR) mission. Three concepts are proposed in this paper with three different targets in terms of entrance into service (2035, 2045, 2050+). First, a summary of first aerodynamic optimizations based on Overall Aircraft inputs for a High Aspect Ratio Strut-Braced Wing (HAR SBW) concept performed in the frame of the U-HARWARD project is proposed. The results show important potential benefits compared to a classical cantilever wing. Then, aerodynamic design and optimization studies on a Blended Wing Body concept are described with a two step approach: the design of the glider configuration first and then a derivative configuration with Boundary Layer ingestion. The synergy between the aircraft concept and this innovative engine integration technology underlines important potential benefits in terms of aerodynamic performance. Finally, the aerodynamic design of an hybrid electric concept equipped with distributed propulsion is described. The integration of such engine concept is very challenging in transonic conditions, a first configuration is proposed with a proper aerodynamic behavior.

This paper presents robot-based Cyber-Physical System (CPS) for lan-guage therapy for children with communication disorders that was created and experimented in frame of the CybSPEED H2020-MSCA-RISE project. The CPS includes humanoid and semi-humanoid robots and is based on a combination of the best of experience, achievements and practices of the researchers from the domains of robotics, AI, system science and speech therapists. All experiments were conducted in accordance with the experimental protocol for measuring of listening, understanding and speaking skills for the verbal language in children with communication disorders, approved by the Ethics Committee for Scientific Research (ECSR) of the IR-BAS. In the paper, detailed description of the CPS, the organisation and conduction of the experiments are given. The first published results are commented which confirm the effectiveness of the robots - based CPS for the children with communication disorders.

Thruster plume simulations often use a hybrid approach, modeling ions as particles and electrons as a fluid. Nevertheless, the definition of the pressure law in the fluid transport of electrons can be quite challenging. In this paper, the consequence of the pressure law assumption on plasma plume simulation results is deeply analyzed. To validate our approach, modeling outcomes must be compared with experimental results. This has been done through comparisons between simulation results and in-flight data taken from the Retarding Potential Analyzers (RPA) placed on the solar arrays on the Russian geostationary telecommunication satellite Express-A #3. The RPA allows the measurements of ion current at different distances and field of view configurations with regard to the thrusters. In this paper, a new method to couple plasma simulation to an RPA analytical model is presented. It enables to couple a plasma simulation to an advanced analytical RPA probe model, taking into account the effects of misoriented RPA. Results demonstrate that the electron pressure law can significantly affect primary ion trajectories. The results are compared to Express-A RPA data., Les simulations de panache de propulseur utilisent souvent une approche hybride, modélisant les ions comme des particules et les électrons comme un fluide. Néanmoins, la définition de la loi de pression dans le transport fluide des électrons peut être assez difficile. Dans cet article, la conséquence de l'hypothèse de la loi de pression sur les résultats de la simulation du panache de plasma est analysée en profondeur. Pour valider notre approche, les résultats de la modélisation doivent être comparés aux résultats expérimentaux. Cela a été fait grâce à des comparaisons entre les résultats de simulation et les données en vol tirées des analyseurs de potentiel retardateur (RPA) placés sur les panneaux solaires du satellite de télécommunication géostationnaire russe Express-A #3. Le RPA permet les mesures de courant ionique à différentes distances et configurations de champ de vision par rapport aux propulseurs. Dans cet article, une nouvelle méthode pour coupler la simulation de plasma à un modèle analytique RPA est présentée. Il permet de coupler une simulation plasma à un modèle de sonde RPA analytique avancé, prenant en compte les effets d'une RPA mal orientée. Les résultats démontrent que la loi de pression électronique peut affecter de manière significative les trajectoires des ions primaires. Les résultats sont comparés aux données Express-A RPA.

In a scenario of always more complex and demanding space missions, enhanced attitude control systems play a key role for satellite design and capabilities improvement. In this paper, an adaptive and robust solution to the pointing angle tracking problem under mixed sources of disturbances is presented. A valid simplified parametric model, of a single axis satellite dynamics, is firstly introduced and discussed, to the objective of effectively accounting for propellant slosh and flexible appendices torque perturbations. The control problem is subsequently solved with a model reference adaptive control approach, namely the Minimal Control Synthesis (MCS). Theoretical fundamentals, architecture implementation and final tuning are reported. A subset of the extensive validation campaign performed is presented and discussed to demonstrate the impressive robustness and performance level reached by the proposed scheme. Limitations and future perspective to tackle them conclude the paper.

Boundary Layer Ingestion (BLI) is a promising concept that helps improving aircraft aeropropulsive performance. However, it remains difficult to bring together OAD (Overall Aircraft Design) process and high-fidelity tools due to the time of response of complex disciplinary tools. ONERA has thus developed a mixed fidelity approach inside its in-house OAD platform. The purpose is to mix conventional and robust OAD methods with high levels of fidelity from disciplinary tools such as CFD (Computational Fluid Dynamics), FEM (Finite Element Model) or CAA (Computational Aero Acoustics). This paper focuses on the integration of rapid CFD tools inside the OAD process, in order to assess BLI benefits. The resulting process is validated against reference and experimental cases when available, or high-fidelity RANS data elsewhere. The paper intends to present the tools and their validation process. These modules are applied to the common inlet concept, which aims at ingesting 100% of the fuselage boundary layer. The results demonstrate the potential gain on the Power Saving Coefficient (up to 3% obtained with the L2 BLI module without resizing loop) but with non-negligible fan losses (up to 1.5%)., L'ingestion de la couche limite (BLI) est l'un des concepts prometteurs permettant d'améliorer les performances aéropropulsives des avions. Plusieurs études ont déjà mis en évidence les avantages de cette technologie, soit au niveau de l'OAD (Overall Aircraft Design), soit avec la CFD (Computational Fluid Dynamics) haute-fidélité. Cependant, il reste difficile de rapprocher les outils OAD et haute-fidélité en raison du temps de réponse des outils disciplinaires complexes. L'ONERA a donc développé une approche de fidélité mixte au sein de sa plateforme interne OAD, en y intégrant des outils disciplinaires rapides. Le but est de mélanger des méthodes OAD conventionnelles et robustes avec des niveaux de fidélité élevés provenant d'outils disciplinaires tels que CFD, FEM ou CAA. Cet article se concentre sur l'intégration d'outils rapides de CFD dans le processus d'OAD, afin d'évaluer les avantages de la BLI.Le processus qui en résulte est validé par rapport à des cas de référence et expérimentaux lorsqu'ils sont disponibles, ou par rapport à des données RANS haute-fidélité. L'article a pour but de présenter les outils, leur processus de validation et les résultats globaux au niveau de l'OAD pour différentes familles d'avions (tels que les avions à moyen courriers ou les jets d'affaires) en utilisant les différents niveaux de fidélité disponibles.

International audience; Sales of electric vehicles, for commercial use and personal use, keep rising. In parallel of the development of the associated Electric Vehicle Charging Infrastructure (EVCI), systems for controlling the charging of EVs will have to be developed in order to reduce the impact of such a development on the power grid. In this paper, we present a supervision system that controls the electric vehicle charging of employees of CEA Cadarache research center. The EVCI of Cadarache, set up in 2016, is constituted of more than 80 22-kW AC charging points spread over 30 zones. This EVCI currently supplies more than 376 vehicles including taxis, service vehicles as well as employees’ vehicles. This infrastructure is one of the largest private EVCIs in the region. The supervision system controls electric vehicle (EV) charging in real-time according to two objectives: respecting user preferences, by fully charging the EV battery, and synchronizing the power consumption of a fraction of the EVCI, i.e., 24 charging points, with the power production of a solar photovoltaic plant. This paper details the supervision system that is used to carry out these experiments and presents experimental results. These results show that it is technically feasible to increase (up to 60 percentage points) the self-production ratio while satisfying EV users.

Gas turbines are for most of them natural gas fired machines that are widely used in the energy industry due to their reliability, high availability, flexibility and their relatively lower GHG emissions compared to other fossil fuels. Researchers are continuously trying to make gas turbine more performing and less emitting. With the emergence of carbon capture and storage in order to reach carbon neutrality, the gas turbine exhaust gas recirculation (EGR) is grabbing even more the attention of researchers. Recirculating the exhaust of gas turbines increases the carbon dioxide concentration in the cycle and thus facilitates the carbon capture process. From a thermodynamic point of view, EGR in gas turbines leads to a change in the working fluid composition and also in the compressor inlet temperature. In addition to impacting the cycle, these changes impact also the compressor and turbine maps leading to a different matching point (pressure ratio). Many researchers tried to study the EGR impact on existing turbines with contradictory results on the performance level. The authors, in a previous paper tried to contribute to this debate by showing separatly the impact of the working fluid composition and the compressor inlet temperature. The compressor and turbine mismatch are highlighted. In this paper, a thermodynamic study is performed from a design perspective using a simple Brayton cycle. It shows that the composition change leads to a lower energy efficiency; however, a design of the compressor and turbine for a better matching point (pressure ratio) reduces the penalty.

Nowadays, in several European Railway networks, the old DC electrification systems are reaching their limits. In some sectors, it is not possible to increase traffic or to operate locomotives at their nominal power rating. The implementation of Fixed Energy Storage Systems (FESS) can be an alternative solution to the creation of a new substation. On the one hand, the FESS limits the contact line voltage drop and, on the other hand, smooths the power absorbed during peak traffic. As a result, the efficiency of the power system can be increased while limiting costs and environmental impact. This paper proposes a new topology of FESS based on isolated DC/DC converters associated to lithium-ion batteries. The galvanic isolation offers a major advantage for operational safety. In the event of fault, the input and output terminals of the DC/DC converters are electrically separated and the contact line voltage can never be directly applied to the batteries. The first part of this paper presents the main characteristics of an elementary module of the FESS. The second part proposes a sizing methodology in a typical case of a line electrified at 1.5 kV DC and shows the limits of using a FESS to reinforce the power supply.

International audience; In this paper, we design a stabilizing statefeedback control law for a system represented by a general class of integral delay equations. Under an appropriate spectral controllability assumption, an implementable control law is proposed. The approach is constructive and makes use of the well-known backstepping methodology. Due to the integral terms present in the original system, the proposed problem requires a Fredholm transform, which is not always invertible. The invertibility of this transformation is proved using an operator formulation. In particular, we show that this invertibility property is a consequence of spectral controllability. The existence of the kernels defining the Fredholm transform is proved similarly by showing that they satisfy an invertible integral equation. Some test case simulations complete the paper.

International audience; Most of the existing near field sources localisation methods are based on an approximatedmodel. Making use of such an approximation brings degradation in the estimation accuracy.In this paper, we propose a correction method to mitigate this problem and improve the estimationperformance of the approximated model based methods. Simulation results show that the proposedtechnique can significantly improve the performance of the classical approximated modelbased near field sources localisation methods.

International audience; The growing demand for cheaper space access calls for a more economically and environmentally sustainable approach for launchers. Concurrently, the shift to smaller satellites and the rise of constellations necessitate launchers capable of precise multi-payload/multi-orbit injection. ASCenSIon (Advancing Space Access Capabilities - Reusability and Multiple Satellite Injection), a Marie Sk\l{}odowska-Curie Innovative Training Network funded by H2020, aims to respond to these demands. This paper describes the activities explored within ASCenSIon dedicated to developing novel green upper stages with multi-payload/multi-orbit injection capability. The aspects investigated here include the general system architecture, innovative solutions for the propulsion system (e.g. Hybrid Rocket Engines (HREs), green propellants and electric pump feeding), Guidance Navigation and Control (GNC) solutions for the multi-payload/multi-orbit injection capability, and reliability aspects of upper stages.\\ First, relevant mission profiles and their main requirements for upper stages are identified. Then, solutions for more environmentally friendly propulsion systems are proposed. Since identifying a good substitute for toxic hydrazine recently became a priority, the use of green propellant technologies will be assessed, tackling specific problems such as benchmarked propulsive performances, storability and material compatibility. Another promising solution for future propulsion systems with lower environmental impact are HREs. They bring benefits in terms of flexibility, safety, reliability and cost. However, high residual mass, oxidizer/fuel ratio shift during operation, low regression rate and combustion inefficiency are some of the challenges that still need to be addressed in their application. In addition, electric pump fed systems, powered by green propellants, may be a game-changer technology for future upper stages. Compared to pressure-fed, it can provide improved performance and lower inert mass. Regarding turbopumps, it may also be advantageous in terms of simplicity and costs. On the other hand, battery mass and thermal control represent some of the drawbacks to overcome.\\ Additionally, the implementation of novel GNC solutions is critical to ensure the multi-payload/multi-orbit injection capability. Different GNC solutions for launchers are presented, as well as an analysis on the optimization techniques for this challenging payload delivery. Finally, the reliability of the launchers is a key aspect to protect both the space environment and the safety of the missions. Novel methods for reliability modelling of launchers are discussed and advantageous system architectures are proposed.\\ These novel technologies being jointly assessed, this paper presents a preliminary analysis of the discussed topics and their interconnections within ASCenSIon, aiming at satisfying new requirements for novel green upper stages.

International audience; The French Radioprotection and Nuclear Safety Institute (IRSN) is interested in contaminant transfers in ventilation of nuclear facilities. Only very few papers present experimental deposition measurements in industrial size ducts and especially in rectangular ducts.This paper presents experimental preliminary results carried out at different locations in rectangular ducts of an industrial size (400*600mm2). Firstly, a protocol is established to measure deposition velocities. Aerosol deposition tests are then performed to measure deposition on bottom, top, left and right walls of straight ducts at different lengths upstream and downstream of singularities. Results are compared with previous studies on smaller size/circular ducts.

This specific paper explores how the in-space 'Electric Propulsion Systems' can turn out to be one of the most promising futuristic spacecraft propulsion technologies, possessing unique advantages over the chemical and other propulsion technologies. The propulsion systems for in-space spacecrafts and aircrafts are different, although sharing certain similarities, and the strategic and systematic approach of exploring the possibilities from the lower atmospheric to the upper atmospheric level is given a good emphasis here, which although is also brief. Moreover, a brief comparison is done between the conventional propulsion systems and the Electrical propulsion systems in general with regard to the specific Impulse and the Thrust generated. In addition, the different variability conditions in the terrestrial atmosphere is discussed in brief in order to account for the various challenges for the in-space electrical propulsion systems and to look for novel and innovative solutions to these challenges. The different types of applications of Electrical propulsion systems and the various thrusters in the current scenario are also mentioned. The main focus is on the feasibility of the Electric Propulsion systems for the low-altitude earth orbiting satellites which are mostly used for earth observation, land, water resources mappings, climate warning systems, earth science etc. at the present moment and thereby strategically going ahead into the electric propulsion systems and their pivotal role in the upper atmosphere of the earth. Although, the Various other applications of the In-Space Electric Propulsion Systems like the Medium Altitude Earth Orbiting satellites mainly used for Navigational purposes, Geostationary satellites used for Telecommunications etc, the Space Transportation-Launcher kick stages, Space Science-Interplanetary Space Exploration etc are beyond the scope of this particular paper, nevertheless these exciting aspects will be explored consecutively. Nevertheless, the various advantages like the reduction of weight of the satellite, Decrease in the launch cost, increase in the lifetime, efficiency and functionality of the satellite, reduction of the quantity of the space debris, the usage of the non-toxic green propellant etc will also be discussed consecutively and are presently beyond the scope of this paper.

International audience; The energy consumption of wireless communicatingdevices as well as their autonomy are two important factors inenergy constrained system such as Wireless Sensor Networks(WSNs). The spectral efficiency is another important metric.The main goal is to study the trade-off between the energyconsumption of the system and it’s spectral efficiency when varyingsystem parameters. In this paper, an uncoded system usingM-ary Quadrature Amplitude Modulation (MQAM) in whichthe spectral efficiency is assumed proportional to its bandwidthefficiency is used. In order to find the balance between spectraland energy requirements, the considered system parameters arestudied. First, a general and comprehensive power model forboth transmitter and receiver is developed. Next, by consideringAdditive White Gaussian Noise (AWGN) channel for point-topointcommunication, the total energy consumption is evaluated.A new approximation for the Bit Error Rate (BER) is adopted.Then, the effects of communication distance and the bandwidthon the optimum spectral efficiency are studied. For a fixed BER,we demonstrate that for each of those parameters, an optimumenergy to spectral-efficiency tradeoff can be found.

International audience; Recently, the concept of robustness measurement has become clearly important especially with the rise of risky events such as natural disasters and mortal pandemics. In this context, this paper proposes an overview of a hardware architecture for massive data collection in the aim of evaluating robustness indicators. This paper essentially addresses the theoretical and general problems that the scientific research is seeking to address in this area, offers a literature review of what already exists and, based on preliminary diagnosis of what the literature has, presents a new approach and some of the targeted findings with a focus on the leading aspects, having a primary objective of explaining the multiple aspects of this research work.

In the present paper, a stable Spectral Difference formulation on triangles is defined using a flux polynomial expressed in the Raviart-Thomas basis up to the sixth-order of accuracy. Compared to the literature on the Spectral Difference approach, the present work increases the order of accuracy that the stable formulation can deal with. The proposed scheme is based on a set of flux points defined in the paper. The sets of points leading to a stable formulation are determined using a Fourier stability analysis of the linear advection equation coupled with an optimization process. The proposed Spectral Difference formulation differs from the Flux Reconstruction method on hybrid grids: the distinction between the two approaches is highlighted through the definition of the number of interior flux points. Validation starts from a convergence study using Euler equations and continues with simulations of laminar viscous flows over the NACA0012 airfoil using quadratic triangles and around a cylinder using a hybrid grid.

Seconde soumission; International audience; Value Analysis (VA) is a collaborative method that could be used to make decision-making in complex projects. System Engineering (SE) is a design method used in complex projects. In complex projects, stakeholders are multiple and carry specific technical, social and environmental expectations that define the value of the project. The aim of this paper is to demonstrate that VA and SE are two complementary approaches to collect and analyzeStakeholder’ expectations in a complex project. The paper presents a literature review on VA and SE that show the complementarity of the methods to involve Stakeholders in projects. From this analysis,a case study is proposed to illustrate the complementarities of the method. The paper concludes that the two methods VA and SE can be combined to analyzeand track multiple dimensions of value (as economic, social and environmental) ina complex projectcontext.

International audience; This paper presents a new concept of Land Mobile Propagation Satellite model. The main idea is to predict the propagation channel based on the analysis of 360° images. To do so, concurrent RF / optic measurements have been done in the past and this paper will present the correlation study between the images and RF signal. Finally, a coupling model RF / images is proposed here, which allows a LMS channel prediction between 1 to 30 GHz.

Cooperative spectrum sensing (CSS) is able to effectively solve the hidden terminal, depth attenuation, multipath shadows and other issues which are not addressed by the single-user sensing. Therefore, it has attracted a large amount of interest and several CSS algorithms have been proposed. However, they are not specifically tailored for cognitive wireless sensor networks (CWSNs) where transmission reliability, power management and interference avoidance are critical issues. In this paper, we propose a robust and energy efficient CSS scheme in CWSNs. Firstly, taking into account the limited energy of sensor node, especially the mobile node, we introduce the nodes of the network into multiple clusters for the CSS in order to save energy consumed in reporting results and exchanging information and extend the lifetime of the network. Secondly, we consider that some cognitive nodes may not work as expected. Hence, facing the problem of faulty nodes in clusters, we propose an evaluation method which considers simultaneously the node reliability and the mutually supportive degree among different nodes to support adapted decisions. Finally, after removing the node of low credibility, the energy efficiency and reliability of each cluster are improved significantly. Simulation results allow to validate that the proposed method outperforms the state of the art in energy efficiency and detection reliability, even in presence of faulty nodes.

International audience; This paper makes a contribution to the problem of incremental class learning, the principle of which is to sequentially introduce batches of samples annotated with new classes during the learning phase. The main objective is to reduce the drop in classification performance on old classes, a phenomenon commonly called catastrophic forgetting. We propose in this paper a new method which exploits the availability of a large quantity of non-annotated images in addition to the annotated batches. These images are used to regularize the classifier and give the feature space a more stable structure. We demonstrate on two image data sets, MNIST and STL-10, that our approach is able to improve the global performance of classifiers learned using an incremental learning protocol, even with annotated batches of small size.

International audience; Image processing is a subset of digital signal processing that has different applications and benefits in different fields. Digital processing is in fact the digital image processing that can be performed with the help of computer science, programming and artificial intelligence. Image processing is one of the applications and subsets of artificial intelligence that, as its name suggests, processes digital images and displays a certain output with specific information based on predefined training. Nowadays, the applications of image processing technology in various fields of science, technology have caused a lot of attention in order to expand the capabilities of arterial intelligence in different engineering challenges. This paper presents recent development and applications in the image processing systems in order to move forward the research filed by reviewing and analyzing recent achievements in the published papers. As a result, advanced image processing systems in different applications can be developed and new techniques in the image processing systems can be introduced.

International audience; In this paper, we design an observer for a system represented by a general class of Integral Delay Equations (IDE). This class of equations encompasses various systems, from chemical or biological processes to the propagation of electric pulses on excitable media. The available measurement corresponds to a discrete and distributed-delayed value of the state. Under an appropriate spectral observability assumption, an implementable observer is proposed. Inspired by the fact that first-order hyperbolic Partial Derivative Equations (PDE) and timedelay systems are closely related, we use a PDE formulation and the well-known backstepping methodology for the design. However, due to integral terms in the dynamics, the use of a Fredholm integral transform is required. We prove its existence and invertibility by using an operator framework. Both proofs derive from the spectral observability assumption. Some test case simulations end the paper.

The paper's main contribution concerns the use of interpolatory methods to solve end to end industrial control problems involving complex linear dynamical systems. More in details, contributions show how the rational data and function interpolation framework is a pivotal tool (i) to construct (frequency-limited) reduced order dynamical models appropriate for model-based control design and (ii) to accurately discretise controllers in view of on-board computer-limited implementation. These contributions are illustrated along the paper through the design of an active feedback gust load alleviation function, applied on an industrial generic business jet aircraft use-case. The closed-loop validation and performances evaluation are assessed through the use of an industrial dedicated simulator and considering certification objectives. Although application is centred on aircraft applications, the method is not restrictive and can be extended to any linear dynamical systems., Comment: 23 pages, 9 figures, submitted to journal

International audience; This paper presents the design, modeling and the experimental build of a 1.5 kW relatively low-cost wind turbine emulator (WTE) equipped by a DC motor (DCM) in order to simulate the static-dynamic behavior of a real wind turbine, including the gearbox. This emulator is integrated into a connected wind energy conversion system chain (WECS), based on the double fed induction generator (DFIG) configuration. The latter ensures the electromechanical conversion. It allows the transfer of active and reactive power with the power grid during hypo and hyper synchronous modes. The aerodynamic emulation principle requires controlling the DC armature current with a PI regulator. This leads to an electrical drive that applies a shaft torque identical to the wind turbine. The current reference is calculated as function of the static settings of the wind turbine and real wind speed data give different operating points. In addition, this paper also proposes to test the Tip Speed Ratio (TSR) based MPPT algorithm to extract the maximum available power on the emulator. The MPPT, the dc motor control and the DFIG power control algorithms are implemented in C, using dSPACE DS1104 control board. The experimental results confirm the effectiveness of the controlled dc motor to emulate the wind turbine with great performances of the proposed MPPT structure.

Sidelobe suppression is an essential criterion for radar performance, especially for off-grid points of sampled signals. In this paper, a mismatched filter that minimizes the average sidelobe energy over a continuous time interval is proposed. The main contribution of this paper is the optimization of this problem for continuous phase modulated signals, which present relevant properties for a dual radar-communications system. It is shown that the optimization problem is convex, thus it provides an optimal solution. The performance of the proposed filter in terms of mean Integrated Sidelobe Level is then compared to the classical matched filter, as well as to the usual on-grid mismatched filter, through simulations. The obtained results show that the proposed filter presents greater performance over the continuous sampling cell than the others.