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International audience; emotions on performance for different types of arithmetic problems and whether this influence changes with aging during adulthood. Based on previous research suggesting that participants use different strategies to solve different types of problems, finding age-related differences in how emotions influence participants' performance on different types of problems would suggest that the effects of emotions on arithmetic performance occur via different mechanisms in young and older adults. Before outlining the logic of the present work, we briefly review previous findings on arithmetic and on effects of negative emotions on arithmetic performance in young and older adults. Previous findings on arithmetic Research in arithmetic aims at determining the crucial factors that influence arithmetic performance and at deciphering mechanisms responsible for how these factors exert their influence. Previous research found that characteristics of tasks, participants, stimuli, and situations influence arithmetic performance. For example, participants are faster when they are asked to accomplish verification tasks (e.g., 4 + 8 = 12. True? False) than when they are asked to accomplish production tasks (e.g., 4 + 8 =?), when they solve tie Ludovic Fabre

International audience; Stakeholders are key elements of complex technical projects. They can determine orientation, evolution and success of the project. They can cause uncertainties, changes in objectives and lead the project to failure. In this context, it is always more important to involve them in project decisions. Value Analysis (VA) is a means to introduce management and decision-making in design of complex projects, based on stakeholder needs. A method named Function Analysis aims at identifying and treating functions that the system has to complete. However, this functional approach does not allow some non-functional attributes to be included in the design phases. This is a lack identified by some engineering companies. The proposed paper aims at identifying the challenges encountered by the Stakeholder approaches to translate their needs into nonfunctional dimensions to deal with VA practices to design technical solutions. The research methodology combines a classical bibliographical analysis on VA that led us to show FA limits. Thus, we propose a Stakeholder-based “Non-Functional Analysis” to determine the non-functional attributes to characterize for the design of complex projects, and an industrial company’s feedback practices on a case study. This will allow practitioners to have a systems approach to Value in the context of a VA but it will also allow scientists to compare theory and lack of practice around the identification and characterization of the needs of a set of stakeholders.

The process of replacing an arbitrary Boolean function by a bijective one, a fundamental tool in reversible computing and in cryptography, is interpreted algebraically as a particular instance of a certain group homomorphism from the X-fold cartesian power of a group G into the automorphism group of the free G-set over the set X. It is shown that this construction not only can be generalized from groups to monoids but, more generally, to internal categories in arbitrary finitely complete categories where it becomes a cartesian isomorphism between certain discrete fibrations.

In this paper, an enhanced solid finite element formulation for rotor dynamics analysis is presented. The element kinematics is first defined with a Total Lagrangian formulation in order to account for possible centrifugal stiffening effect and its associated pre-stress deformation. The novelty of the three-dimensional element proposed in this study is then to correctly consider the effect of inertia due to small rotational deformation occurring around the pre-stressed equilibrium position. The rotational motion is characterized by interpolation of the translational degrees of freedom of the element. The accuracy and convergence of the proposed finite element are tested on several numerical examples consisting of a rotating rigid disk and a rotating Timoshenko beam with different slenderness ratios. All results agree well with analytical solutions excerpted from literature and demonstrate the usefulness and applicability of the proposed finite element formulation.

This article proposes to determine and identify the physical contributions that drive the internal resonance between the bending and torsion modes of a blade. The blade is modeled as a nonlinear beam including warping, twist and pre-bending, and a discretization scheme based on a Rayleigh-Ritz approximation is performed. The modal properties of the model are compared and validated using beam theory and finite element modeling. Several configurations of the model allowing the occurrence of an internal resonance between the first torsional and the second bending modes are considered. The frequency responses near the second bending mode are obtained through the Harmonic Balance Method coupled with a branch switching algorithm to locate and track bifurcated branches related to internal resonances. Attention is paid to the identification of the geometrical nonlinear terms that enable the appearance of an internal resonance. With the help of a multiple scale analysis, it is shown that it is essentially driven by a small set of coupling parameters involving bending and torsion displacements of the commensurate modes. It is also observed in a rotating situation thanks to the hardening of the bending mode.

International audience; A Design of Experiment method was applied combined with a performance prediction program to assess the influence of four design parameters on the propulsive capacity of kites used as auxiliary propulsion for merchant vessels. Those parameters are the lift coefficient, the lift to drag ratio or drag angle, the maximal load bearable by the kite and the ratio of the tether length on the square root of the kite area. These parameters are independent from the kite area and, therefore, they could be used with various kite ranges and types. The maximum wing load parameter is the one that shows the most influence on the propulsive force. Over 50% of the gains obtained through this study are directly attributable to it. Then the ratio of the tether length on the square root of the kite area comes as the second greatest influence factor for true wind angles above 70°. While the drag angle is more influential for the narrower angles. In fact, the most substantial gains are made upwind.

International audience; Over the past decade, interest in autonomous vessels significantly increased as the technology improved, especially in the automotive industry. Unlike cars, ships travel in a wild environment and maritime lanes are not limited by white lines. This makes the design of fully autonomous vessels even more challenging. Additionally, the need to reduce greenhouse gas emissions led to a renewed interest in wind propulsion. Sailboats have several advantages, such as full energy autonomy and a limited environmental impact. The Microtransat Challenge, which consists of crossing the Atlantic Ocean, is a tremendous test field. This paper describes, within that frame, a design procedure for the development of a robust fully autonomous sailboat to be deployed for long-term missions. In this paper, the mechanical and electronic design strategies are presented. A focus is on reliability and power management. Moreover, a test procedure for validating each design increment is described as well as a path plan that considers the risk of collision and weather routing with wind and currents. The Microtransat remains a challenge that no autonomous ship has ever succeeded (and has been completed by a single unmanned vessel, SB Met in 2018). However, the results by Breizh Tigresse and Sealeon in 2015 and 2018 made a step forward in terms of time and distance. They are presented and analyzed in this work

A topological commutative ring is said to be rigid when for every set $X$, the topological dual of the $X$-fold topological product of the ring is isomorphic to the free module over $X$. Examples are fields with a ring topology, discrete rings, and normed algebras. Rigidity translates into a dual equivalence between categories of free modules and of "topologically-free" modules and, with a suitable topological tensor product for the latter, one proves that it lifts to an equivalence between monoids in this category (some suitably generalized topological algebras) and coalgebras. In particular, we provide a description of its relationship with the standard duality between algebras and coalgebras, namely finite duality., This version only deals with the monoidalily of the equivalence

Flat hourglass specimens are proposed to assess the compressive behaviour of FRP utilizing two testing techniques. The hourglass shape helped to ensure failure at the centre of the specimen and to minimize in-plane stress concentration in this zone. Four-point bending tests are carried out and measures are performed via DIC. A procedure to calculate bending moment is proposed and validated in presence of large displacements. To evaluate the specimen and the method proposed, two different materials were tested, an E-glass/Epoxy unbalanced woven and a Carbon/PEEK balanced woven. In a second time ASTM D695 compression tests are carried out on the E-Glass/Epoxy composite to compare the hourglass specimens to the standardized dog-bone. The two testing techniques are analysed and compared.

International audience; A numerical solver based on the immersed boundary method has been recently developed on OpenFoam [3], a free software. In this study, we investigate the Immersed Boundary Method (IBM) at low Reynolds number (Re=1000) for incompressible flow around NACA 0012 airfoil and then around a flat plate and a NACA 23012 airfoil in rotation (from 0° to 90°). The Leading-edge suction parameter Discrete Vortex Method (LDVM) is also investigated in the models using a rotation of the airfoils. LIST OF SYMBOLS c Chord length Lift coefficient Drag coefficient n Time step p Pressure Reynolds number t Time u Flow velocity û Estimated velocity during the predictor step ∞ Input velocity

The Android operating system is the most spread mobile platform in the world. Therefor attackers are producing an incredible number of malware applications for Android. Our aim is to detect Android's malware in order to protect the user. To do so really good results are obtained by dynamic analysis of software, but it requires complex environments. In order to achieve the same level of precision we analyze the machine code and investigate the frequencies of ngrams of opcodes in order to detect singular code blocks. This allow us to construct a database of infected code blocks. Then, because attacker may modify and organized differently the infected injected code in their new malware, we perform not only a semantic comparison of the tested software with the database of infected code blocks but also a structured comparison. To do such comparison we compute subgraph isomorphism. It allows us to characterize precisely if the tested software is a malware and if so in witch family it belongs. Our method is tested both on a laboratory database and a set of real data. It achieves an almost perfect detection rate.

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; Cognitive fatigue is a problem for the safety of critical systems (e.g., aircraft) as it can lead to accidents, especially during unexpected events. In order to determine the extent to which it disrupts adaptive capabilities, we evaluated its effect on online and anticipatory control. Despite numerous studies conducted to determine its effects, the exact mechanism(s) affected by fatigue remains to be clarified. In this study, we used distribution and electromyographic analysis to assess whether cognitive fatigue increases the capture of the incorrect automatic response or if it impairs its suppression (online control), and whether the conflict adaptation effect is reduced (anticipatory control). To this end, we evaluated the evolution of the performance over time during the Simon task, a classic conflict task that elicits incorrect automatic responses. To accentuate the presence of fatigue during the Simon task, two groups previously performed a dual-task with two different cognitive load levels to create two different levels of fatigue. The results revealed that time on task impaired online control by disrupting the capacity to suppress the incorrect response but leaving unaffected the expression of the automatic response. Furthermore, participants emphasized speed rather than accuracy with time on task, with in addition more fast guesses, suggesting that they opted for a less effortful response strategy. As the implementation of the suppression mechanism requires cognitive effort, the conjunction of these results suggests that the deficits observed may be due to disengagement of effort over time rather than reflecting an incapacity to make an effort.

International audience; Le Brexit a souvent été décrit et perçu comme un isolement géopolitique du Royaume-Uni. Pourtant depuis 2016, Londres élabore une stratégie d’influence mondiale : signature d’accords économiques bilatéraux tous azimuts (pas moins de 20 accords de libre-échange, couvrant près de cinquante pays répartis sur les 5 continents), une nouvelle doctrine stratégique globale marquant le retour de la présence britannique à l’est du canal de Suez et un renforcement notable de sa présence militaire maritime. L’Océanie constitue l’un des axes majeurs de cette nouvelle politique, à travers le Pacific Uplift. La France, dernier État de l’Union européenne (UE) encore présent dans le Pacifique, peut profiter de ce nouveau schème géostratégique pour consolider sa relation avec le partenaire britannique dans la région océanienne.

The Android operating system is the most spread mobile platform in the world. Therefor attackers are producing an incredible number of malware applications for Android. Our aim is to detect Android's malware in order to protect the user. To do so really good results are obtained by dynamic analysis of software, but it requires complex environments. In order to achieve the same level of precision we analyze the machine code and investigate the frequencies of ngrams of opcodes in order to detect singular code blocks. This allow us to construct a database of infected code blocks. Then, because attacker may modify and organized differently the infected injected code in their new malware, we perform not only a semantic comparison of the tested software with the database of infected code blocks but also a structured comparison. To do such comparison we compute subgraph isomorphism. It allows us to characterize precisely if the tested software is a malware and if so in witch family it belongs. Our method is tested both on a laboratory database and a set of real data. It achieves an almost perfect detection rate., Comment: in French

International audience; Predicting the vibratory response of bladed-disks in turbomachinery is of the utmost importance to design a reliable and optimized engine. Yet, such simulations are challenging mainly due to the large size of the finite-element model used to describe the system, the existence of random mistuning coming from manufacture tolerances, and the nonlinear effects arising from the different components and their coupling. As a consequence, very few reduced-order models handling nonlinear mistuned systems have yet been proposed and the existing ones try to find the best compromise between a computationally efficient simulation and a correct description of the nonlinear phenomena. In this paper, a novel approach is proposed to tackle this challenge. Its key ideas rely on the substructuring concept and the cyclic properties of the structure. A reduction basis composed of cyclic complex nonlinear normal modes is created on each sector of the system leading to a compact nonlinear superelement per sector. The system is then assembled and a synthesis simulation is performed. Due to the main concepts employed, the method is referred to as the Substructuring method based on Nonlinear Cyclic Reduction (SNCR). It is validated on a finite element model of a tuned, a randomly mistuned and an intentionally mistuned bladed-disks. It will be shown to be fast and accurate despite strong nonlinearities. Due to its flexibility and efficiency, the method is expected to have a wide range of possible applications within the community.

International audience; This paper presents sea trials on a 6-m boat specifically designed for kite propulsion. The kite control was automatic or manual, dynamic or static, depending on the point of sailing. The measurement system recorded boat motion and load generated by the kite. A particular attention was paid to wind measurement with several fixed and mobile locations directly on the kiteboat or in the vicinity. A high resolution weather modelling showed that a classical power law, describing the wind gradient, was not satisfactory to get the wind at kite location. 5-min measurement phases were systematically recorded. In the end, 101 runs were carried out. Data were processed with the phase-averaging method in order to produce reliable and accurate results. © 1996-2020 MDPI (Basel, Switzerland) unless otherwise stated

International audience; This paper presents a series of dynamic simulations for a ship towed by kite. To ensure time efficient computations, seakeeping analysis with forward speed correction factors is carried out in the frequency domain and then transformed in the time domain by convolution. The seakeeping modeling is coupled with a zero-mass kite modeling assuming linear dependence of aerodynamic characteristics with respect to turning rate. Decoupled (segregated) and coupled (monolithic) approaches are assessed and compared in different environmental conditions. Results show that in regular beam waves, strong interactions between the kite and the ship motions are captured by the monolithic approach. Around the wave frequency, especially for the lower one tested (0.4 rad/s), a kite lock-in phenomenon is revealed. It is concluded that the mean kite towing force can be increased whereas the ship roll amplitude can even be decreased compared to a non-kite assisted ship propulsion configuration.

This paper presents the development of a code, called GEBTAero, dedicated to very flexible aircraft (VFA) aeroelasticity and especially the evaluation of aeroelastic tailoring effect on critical speeds. GEBTAero is an open source code consisting in a tightly coupling between a geometrically exact beam theory -and a finite state induced flow unsteady aerodynamic model, including an homogenisation tool. This model has been implemented in Fortran using GEBT code and optimised open source libraries with particular focus on computation speed. Besides a non linear transient dynamic simulation capacity, a particular focus is put on the fast critical speed computation strategy using a non-iterative modal approach about the geometrically non linear deformed shape of the wing with the computation of only a few aeroelastic modes. Computation speed and accuracy of this implementation is assessed using widely used aeroelastic test cases and compared successfully to other aeroelastic codes. Configurations using aeroelastic tailoring, which are the core target of this solver, are then evaluated numerically on a representative high aspect ratio anisotropic composite wing and a simple 2-ply composite laminates with both variable ply orientations. It illustrates the strong correlation between the structural bending/twisting coupling of an unbalanced composite laminates and its critical aeroelastic speed. It also shows the high sensitivity of ply orientation on the aeroelastic behaviour.