1,093 research outputs found

    On compensation schemes for data sharing within the european REACH legislation

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    Article 30 of Regulation (EC) No 1907/2006 concerns the sharing of data between users of a chemical substance. We study this bargaining problem by means of a special class of games in coalitional form called data games (Dehez and Tellone [10]). For such problems, compensation schemes specify how the data owners should be compensated by the agents in needs of data. On the class of data games, the Core, the Nucleolus and the Shapley value provide relevant compensation schemes. We provide three comparable axiomatic characterizations of the set of all (additive) compensation schemes belonging to the Core, of the Nucleolus and of the Shapley value. The axioms reflects principles of various theories of justice

    La construction d’une sanction: Le cas des pĂ©nalitĂ©s de retard dans les centres de loisirs de la commune d’AsniĂšres-sur-Seine

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    This paper presents a natural experiment where a French city decided to fine parents who pick up their children late in municipal day-care centers. After five months of implementation of this scheme, contrary to the findings of Gneezy and Rustichini (2000a), the number of delay has been significantly decreased. We attribute this difference to three specific features of the French city sanction system: 1/ it has not been imposed top-down but built afterimplication of all stakeholders, including parents (involved in a working group); 2/ Communication towards parents in order to justify the fine focused on non-financial elements such as the problems that delay induce for day-care centers personals rather than on the financial costs of delays; 3/ the fine is proportional to the length of the delay and to the income of the parents and, in extreme cases, there is the possibility to exclude children.Cet article prĂ©sente une expĂ©rience naturelle oĂč une commune française a dĂ©cidĂ© de sanctionner financiĂšrement les parents venant chercher leurs enfants avec retard dans les centres de loisirs communaux. AprĂšs cinq mois de mise en Ɠuvre de ce dispositif, contrairement aux conclusions obtenues par Gneezy et Rustichini (2000a), il est constatĂ© une diminution significative du nombre de retards. Nous attribuons cette diffĂ©rence Ă  trois caractĂ©ristiques spĂ©cifiques du dispositif de sanction français : 1/ celui-ci n’a pas Ă©tĂ© imposĂ© de maniĂšre brutale mais construit aprĂšs consultation des diffĂ©rentes parties prenantes, y compris les parents (impliquĂ©s dans un groupe de travail) ; 2/ La communication auprĂšs des parents pour justifierl’introduction de cette sanction a Ă©tĂ© centrĂ©e sur les motivations non financiĂšres c’est-Ă -dire sur les nuisances que les retards induisaient pour le personnel plutĂŽt que sur le coĂ»t financier des retards ; 3/ la sanction financiĂšre est proportionnelle Ă  la durĂ©e du retard et au revenu des parents et, en dernier ressors, existe la possibilitĂ© d’exclure les enfants

    Dynamic equilibrium in games with randomly arriving players

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    This note follows our previous works on games with randomly arriving players [3] and [5]. Contrary to these two articles, here we seek a dynamic equilibrium, using the tools of piecewise deterministic control systems The resulting discrete Isaacs equation obtained is rather involved. As usual, it yields an explicit algorithm in the finite horizon, linear-quadratic case via a kind of discrete Riccati equation. The infinite horizon problem is briefly considered. It seems to be manageable only if one limits the number of players present in the game. In that case, the linear quadratic problem seems solvable via essentially the same algorithm, although we have no convergence proof, but only very convincing numerical evidence. We extend the solution to more general entry processes, and more importantly , to cases where the players may leave the game, investigating several stochastic exit mechanisms. We then consider the continuous time case, with a Poisson arrival process. While the general Isaacs equation is as involved as in the discrete time case, the linear quadratic case is simpler, and, provided again that we bound the maximum number of players allowed in the game, it yields an explicit algorithm with a convergence proof to the solution of the infinite horizon case, subject to a condition reminiscent of that found in [20]. As in the discrete time case, we examine the case where players may leave the game, investigating several possible stochastic exit mechanisms. MSC: 91A25, 91A06, 91A20, 91A23, 91A50, 91A60, 49N10, 93E03. Foreword This report is a version of the article [2] where players minimize instead of maximizing, and the linear-quadratic examples are somewhat different.On dĂ©termine les stratĂ©gies d'Ă©quilibre dans un jeu dynamique oĂč des joueurs identiques arrivent de façon alĂ©atoire, comme, par exemple, des congĂ©nĂšres arrivant sur une mĂȘme ressource. On considĂšre aussi divers mĂ©canismes de sortie alĂ©atoire. On obtient des thĂ©orĂšmes d'existence et des algorithmes de calcul, plus explicites dans le cas particulier linĂ©aire quadratique. Toute l'Ă©tude est conduite en horizon fini et en horizon infini, et en temps discret et en temps continu.Ce rapport est une version du working paper CRESE des mĂȘmes auteurs (en Ă©conomie mathĂ©matique), rĂ©fĂ©rence [2], mais oĂč les joueurs minimisent au lieu de maximiser, et les exemples linĂ©aires quadratiques sont un peu diffĂ©rents

    Viscosity and Electrical Conductivity of Aqueous NaCl Solutions with Dissolved CO2

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    AbstractWith the perspective of long term CO2 storage, thermodynamic data are necessary for the simulations of CO2 injection in aquifers of depleted oil reservoirs. We focus here on the determination of the resistivity and viscosi ty of aqueous NaCl solutions with dissolved CO2. It is well known that dissolved CO2 increases slightly the water density. Recently, Bando et al. (2004) measured the viscosity of CO2 saturated brines and found an increase of viscosity with increasing amoun t of dissolved CO2. For resistivity, no data is available to our knowledge.We evaluated the effect of dissolved CO2 simultaneously on the resistivity and viscosity of three NaCl solutions covering the range of salinity usually encountered in potential CO2 storage geological formations. At a constant temperature of 35 ∘C, we show that the variation of resistivity and viscosity are proportional to the amount of dissolved CO2. For viscosity, our data are in agreement with previous observations. The observed variations are small, at maximum of the order of 10%. The increase of viscosity is well correlated with the variation of conductivity because ions are moving in a more viscous solvent and th erefore conductivity decreases. For the temperature dependence, w e used the Arps model to describe the measured variation of conductivity as a function of temperature. We propose a simple model to take into account the small modifications of conductivity and viscosity as a function of the dissolved CO2 fraction and temperature. Finally, we examine two potential impact s of these findings

    "Plus, n'est pas nécessairement mieux" ou la difficulté de faire apparaßtre le(s) vraies question(s) de droit dans la masse des décisions des autorités de concurrence

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    National audienceIs there a real case law through competition authorities in France.Examen des décisions des autorités de concurrence françaises, de leur nombre et de leurs qualités en droit et possibilité de dégager une véritable jurisprudence

    Balanced collective contributions, the equal allocation of non-separable costs and application to data sharing games

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    The axiom of Balanced collective contributions is introduced as a collective variant of the axiom of Balanced contributions proposed by Myerson (1980). It requires that the identical average impact of the withdrawal of any agent from a game on the remaining population. It turns out that Balanced collective contributions and the classical axiom of Efficiency characterize the equal allocation of non-separable costs, an allocation rule which is extensively used in cost allocation problems and in accounting. For instance, the equal allocation of non-separable costs coincides with the Nucleolus on the class of data sharing games within the European REACH legislation. While our result does not hold on data sharing games, we provide comparable characterizations of the equal allocation of non-separable costs and the Shapley value

    Age differences in the motor control of speech : an fMRI study of healthy aging

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    Healthy aging is associated with a decline in cognitive, executive, and motor processes that are concomitant with changes in brain activation patterns, particularly at high complexity levels. While speech production relies on all these processes, and is known to decline with age, the mechanisms that underlie these changes remain poorly understood, despite the importance of communication on everyday life. In this cross‐sectional group study, we investigated age differences in the neuromotor control of speech production by combining behavioral and functional magnetic resonance imaging (fMRI) data. Twenty‐seven healthy adults underwent fMRI while performing a speech production task consisting in the articulation of nonwords of different sequential and motor complexity. Results demonstrate strong age differences in movement time (MT), with longer and more variable MT in older adults. The fMRI results revealed extensive age differences in the relationship between BOLD signal and MT, within and outside the sensorimotor system. Moreover, age differences were also found in relation to sequential complexity within the motor and attentional systems, reflecting both compensatory and de‐differentiation mechanisms. At very high complexity level (high motor complexity and high sequence complexity), age differences were found in both MT data and BOLD response, which increased in several sensorimotor and executive control areas. Together, these results suggest that aging of motor and executive control mechanisms may contribute to age differences in speech production. These findings highlight the importance of studying functionally relevant behavior such as speech to understand the mechanisms of human brain aging

    Interaction of Guided Waves with Cracks in an Embedded Multilayered Anisotropic Plate by Using a Boundary Element Approach

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    In this work, the interaction of a transient guided elastic wave with a planar crack is studied by using a Boundary Finite Element approach on the crack. The originality of this work is to use the numerical Green functions of the multilayered plate. So, the key point of the method is to calculate rapidly and accurately these Green functions for such complex plane structures. For the space variables related to the plate surface, the fields are transformed in the 2D Fourier associated to the wave-vectors on this surface, and they are expressed in the partial-wave basis [1]. To ensure causality, the time dependence is dealt with in the Laplace domain. Surprisingly, this method, that involves 2D Fourier transform on the surface coupled with Laplace transform, has been rarely used in the ultrasonic community, while it is a useful tool which complements the much used technique based on generalized Lamb wave decomposition. By avoiding mode analysis, which can be problematic in some cases, exact numerical calculations of Green functions can be made in a relatively short time for immersed plates made of a stack of anisotropic viscoelastic layers. Even for 3D cases, numerical costs are relatively low. Numerical results show the effectiveness of this method. The examples presented emphasize the quality of the model and the robustness of the algorithm. Comparisons with Finite Element show excellent agreement. This approach is fast and low memory consuming for planar defects in arbitrary layered media, and can be extended to arbitrary shapes and boundary conditions for, of course, a higher computational cost. It is valid in 3D, however only the 2D case is considered in this work
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