Défense de la nation contre prospérité de la discipline : engagement militaire et institutionnalisation de la psychologie au Canada

RésuméCet article examine les effets de l’engagement militaire des psychologues canadiens sur la montée de leur discipline et de leur profession à partir de la Deuxième Guerre mondiale. Il propose que le patronage et les usages militaires de la psychologie ont tout particulièrement favorisé l’extension de l’expertise psychologique hors de l’enseignement supérieur en permettant aux psychologues de s’approprier de nouveaux rôles, de gagner de nouveaux milieux, et de renforcer la valorisation de la recherche psychologique à l’échelle nationale. En se profilant sur la conjoncture extérieure, la psychologie a obtenu de nouvelles ressources (symboliques et matérielles) et prospéré socialement et institutionnellement. L’appréciation des effets de cette détermination exogène sur l’autonomie et sur la qualité du savoir disciplinaire et professionnel demeure une question d’ordre empirique, sociohistorique, ne relevant pas de motifs intrinsèques.This article contributes to our knowledge about the rise of the social and human sciences through an examination of military uses of psychology in Canada and this field sensibility to external demand. The national crisis caused by World War II and the Cold War were perceived by psychologists as sizeable opportunities to promote psychological expertise outside academe and to strengthen the social authority of their discipline and profession. By the way of military patronage and psychological contribution to National defense, psychological expertise then gained new symbolic and material resources. Does it mean that this field exogeneity undermine its disciplinary practices or knowledge production? It is said that this is an empirical question that bears no univocal answers

Does Resorting to Online Dispute Resolution Promote Agreements? Experimental Evidence

This paper presents an experiment performed to test the properties of an innovativebargaining mechanism (called automated negotiation) used to resolve disputes arising fromInternet-based transactions. The main result shows that the settlement rule tends to chillbargaining as it creates incentives for individuals to misrepresent their true valuations, whichimplies that automated negotiation is not able to promote agreements. However, this perverseeffect depends strongly on the conflict situation. When the threat that a disagreement occurs ismore credible, the strategic effect is reduced since defendants are more interested inmaximizing the efficiency of a settlement than their own expected profit. The implications ofthese results are then used to discuss the potential role of public regulation and reputationmechanisms in Cyberspace: Online Dispute Resolution, Electronic Commerce, Bargaining, Arbitration,Experimental Economics

Modeling and Feedback Control for Air Flow Regulation in Deep Pits

International audienceWe consider the problem of regulating the air quality in underground extraction rooms for mining industry. This is a challenging control problem where the flow dynamics, the interconnections between subsystems and the time-varying topology have to be taken into account along with real-time computation constraints. Our work is focused on the deep pit part of the ventilation system, which brings fresh air at a specified pressure to the extraction levels. The flow interactions and main automation elements are first presented, with a real-time engineering model of the complete mine ventilation system. A novel control-oriented model focused on the pressure dynamics is then introduced, as a convective-resistive partial differential equation (PDE) with multiple inputs where the time-varying transport coefficients are estimated based on the distributed measurements. A fast predictive controller (FPC) is finally proposed to compensate the pressure losses due to friction and multiple flow exhausts thanks to the ventilation pit input pressure regulation. Simulation results illustrate the efficiency of the modeling and control algorithms

Bounded Control of a General Extended Chained Form Systems

International audienceIn this paper, a state feedback control is proposed for the control of second-order chained form system with bounded inputs. The feedback law is based on a receding horizon strategy that provides convergence of the system to any desired final state. Numerical simulations are given to show the effectiveness of the proposed control strategy

A prediction based controller for trajectories tracking and stabilization of a non-minimum phase PVTOL aircraft

International audienceIn this paper a nonlinear prediction-based control approach is proposed for stabilization of Planar Vertical TakeOff and Landing (PVTOL) aircraft. This system has fewer control inputs than degrees of freedom (i.e. under-actuated) and has unstable zero dynamics (i.e. non-minimum phase). The proposed control approach is based on partial feedback linearization, which allows the emergence of a completely linearized subsystem and internal dynamics. Then prediction based optimal trajectories are proposed for the linearized variables, where the optimization objective is to enhance the behavior and the stability of the internal dynamics. Stability analysis of the closed-loop system is performed using a graphical tool based on Poincaré's section. The performance of the proposed scheme is illustrated through simulations

Bio-Inspired Hovering Control for an Aerial Robot Equipped with a Decoupled Eye and a Rate Gyro

International audienceThis work provides an hovering control strategy for a sighted robot, the eye of which being decoupled from the body and controlled by means of a tiny rotative piezo motor. The main purpose of this paper is to show the effectiveness and the efficiency of this fundamental bio-inspired mechanical decoupling. Indeed, it exhibits several benefits: * it enables to stabilize the robot's gaze on the basis of three bio-inspired oculomotor reflexes (ORs) : a visual fixation reflex (VFR), a translational and rotational vestibulo- ocular reflexes (tVOR and rVOR), * the eye can better, quickly and accurately compensate for sudden, untoward disturbances caused by the vagaries of the supporting head or body, * it yields a reference visual signal that can be used to unbias the rate gyro used to implement the VORs and to stabilize the hovering robot, * it increases the tracking accuracy with moving targets compared to without OR, This paper shows also that lateral disturbances are rejected 2 times faster with the decoupled eye robot, and roll perturbations induce a retinal error 20 times smaller. The occulomotor reflexes enables to cancel retinal error 6 times faster with 5 times lower retinal error picks. The conclusion of the paper is that decoupled eye must be considered as an efficient autonomous flight solution

Attitude and Position Control of a Flapping Micro Aerial Vehicle

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Event-based Stabilization of Nonlinear Time-Delay Systems

International audienceIn this paper, a universal formula is proposed for event-based stabilization of nonlinear time-delay systems affine in the control. The feedback is derived from the original one proposed by E. Sontag (1989) and previously extended to event-based control of nonlinear undelayed systems. Under the assumption of the existence of a control Lyapunov-Krasovsky functional, it enables smooth (except at the origin) asymptotic stabilization while ensuring that the sampling intervals do not contract to zero. Global asymptotic stability is obtain under the small control property assumption. Moreover, the control can be proved to be smooth anywhere under certain conditions. Some simulation results highlight the ability of the proposals

Constrained Model Predictive Control of a Skid-Steering Mobile Robot

International audienceAbstract—In this paper, a kinematic model of a four-wheelskid-steering mobile robot is presented and a receding horizonstabilizing control law for the system is developed, based onthe optimization of a quadratic cost function on the systemstates and control inputs. Global asymptotic stability of thenominal system with actuator saturation constraints is analyticallyproven and a simple dynamical model is constructed forvalidation purposes. The robustness and performance of thecontroller were tested under simulation on both models andthe results are presented and discussed

Suivi de la température de surface dans les zones de pergélisol arctique par l'utilisation de données de télédétection inversées dans le schéma de surface du modèle climatique canadien (CLASS)

Les régions de haute latitude sont actuellement les plus sensibles aux effets du réchauffement climatique, et avec des élévations de température pouvant atteindre les 3 à 8 ◦C au niveau du pôle sur les 100 prochaines années. Les pergélisols (sols présentant des températures négatives deux années consécutives) sont présents sur 25 % des terres émergées de l’hémisphère nord et contiennent de grandes quantités de carbone « gelé », estimées à 1400 Gt (40 % de la quantité de carbone terrestre global). Des études récentes ont montré qu’une partie non négligeable (50 %) des premiers mètres des pergélisols pourraient fondre d’ici 2050, et 90 % d’ici 2100. Le but de l’étude est donc d’améliorer les moyens de suivi de l’évolution des températures du sol dans les zones arctiques, et plus particulièrement dans les régions couvertes de neige. L’objectif est de décrire la température du sol tout au long de l’année y compris sous un manteau neigeux, et d’analyser l’évolution de l’épaisseur de la couche active des pergélisols en relation avec la variabilité du climat. Nous utilisons des données satellites (fusion de données de température dans l’infra-rouge thermique “LST” et de température de brillance micro-onde AMSR-E « Tb ») assimilées dans le schéma de surface du modèle climatique canadien (CLASS, V 3.6) couplé à un modèle simple de transfert radiatif (HUT). Cette approche bénéficie des avantages de chaque type de donnée de manière à réaliser deux objectifs spécifiques : 1-construire une méthodologie solide permettant de retrouver les températures du sol, avec et sans neige, en zone de toundra, et 2-à partir de ces températures du sol, dériver la durée de fonte estivale et l’épaisseur de la couche active du pergélisol. Nous décrivons le couplage des modèles ainsi que la méthodologie permettant l’ajustement des paramètres météorologiques d’entrée du modèle CLASS (essentiellement les températures de l’air et les précipitations issues de la base de données des réanalyses météorologiques NARR) de manière à minimiser les LST et Tb simulées en comparaison aux mesures satellites. Par rapport aux données de mesures de sol de stations météorologiques prises comme référence pour validation dans les zones de toundra d’Amérique du Nord, les résultats montrent que la méthode proposée améliore significativement la simulation des températures du sol lorsqu’on utilise les données LST MODIS et Tb à 10 et 19 GHz pour contraindre le modèle, en comparaison avec les sorties du modèle sans les données satellites. Dans ce processus d’inversion, la correction de l’évolution des conditions de neige au cours de l’hiver contrainte avec le rapport de polarisation à 11 GHz constitue une approche originale. Une analyse de l’erreur pour 4 sites de toundra et sur plusieurs années (18 cas) est effectuée pour la période estivale (1,7 -3,6 K) ainsi que pour la période hivernale couverte de neige (1,8 -3,5 K). L’indice des degrés-jours de fontes annuel, dérivé des températures du sol simulés par notre approche, permet de cartographier les zones de pergélisols continu en accord avec les cartes actuelles. Un meilleur suivi des processus d’évolution des pergélisols, et tout particulièrement de l’impact de la couverture de neige, devrait permettre une meilleure compréhension des effets du réchauffement climatique sur la fonte des pergélisols et l’avenir de leurs stocks de carbone.Abstract : High latitude areas currently are the most sensitive to global warming effects. In the next 100 years, temperature could rise up to 3 to 8 ◦C at the North Pole. Permafrost (ground with negative temperatures two years in a row) represents 25% of northern hemisphere lands, and contains huge quantities of "frozen" carbon estimated at 1400 Gt (40 % of the global terrestrial carbon). Recent studies showed that a part (50 %) of the permafrost first few meters could melt by 2050, and 90 % by 2100. The goal of our study is to improve our understanding of ground temperature evolution in arctic areas, especially in snow covered regions. The objective is to discribe the ground temperature all year long with and without a snow cover, and to analyze the evolution of the permafrost’s active layer in relation with the climate variability. We use remote sensing data (fuzzed of MODIS "LST" surface temperatures and AMSR-E "Tb" brightness temperatures) assimilated in the canadian landscape surface scheme (CLASS) coupled to a simple radiative transfer model (HUT). This approach takes into account the advantages of each kind of data in order to achieve two objectives : 1 - build a solid methodology allowing to retrieve ground temperatures, with and without a snow cover, in tundra areas ; 2 - from those retrieved ground temperatures, derive the summer melting duration which can be linked to the permafrost active layer thickness. We describe the models coupling as well as the methodology allowing the adjustement of CLASS input meteorological parameters (essentially the air temperatures and precipitations from the NARR meteorological data base) in order to minimize the simulated LST and Tb in comparison to remote sensing data. By using meteorological station’s ground temperature measurments as a reference for validation in North America tundra areas, results show that the proposed method improves the simulation of ground temperatures when using LST MODIS and Tb at 10 and 19 GHz data to constrain the model, in comparison with model outputs without satellite data. Using the Tb polarization ratio H/V at 10 GHz allows an improvement of the constrain on winter period simulations. An analyze of the error is conducted for summer (1,7 - 3,6 K) and winter (1,8 - 3,5 K). We present climatic applications for future work that meets the second objective of the Ph.D. A better understanding of evolution processes of permafrost, and particularly of the impact of the snow cover, should allow us a better understanding of global warming effects on the permafrost’s melting and the future of their carbon stocks