Analyse prospective de la rémunération des auteurs, artistes-interprètes et producteurs à l'ère de la numérisation

Les auteurs analysent les conséquences financières, présentes et à venir, de la révolution provoquée par les nouveaux moyens de communication de masse (chaînes de télévision câblées, lecteurs de DVD, Internet, etc.) dans la diffusion des oeuvres protégées par le droit de la propriété littéraire et artistique auprès d'un public de plus en plus vaste. Ils décrivent successivement l'extension continue de la notion d'oeuvre protégée, l'augmentation concomitante des revenus des droits patrimoniaux et les problèmes posés par la protection de ces droits contre le « piratage » (lois Hadopi), et enfin les perspectives de gestion de ces droits par le biais de nouvelles licences légales gérées par des Sociétés de Perception et de Répartition des Droits (SPRD).Licences légales ; Lois Hadopi ; OEuvres protégées ; Piratage ; Propriété littéraire et artistique ; SPRD

Analyse prospective de la rémunération des auteurs, artistes-interprètes et producteurs à l’ère de la numérisation

The authors analyse the present and coming financial consequences of the revolution caused by the new communication media (TV broadcast, DVD, internet…) towards the diffusion of literary and artistic works protected by intellectual property laws to an increasingly larger public. They successively describe the ongoing extension of the sense of protected works, the concomitant increase of incomes of property rights and the problems raised by the protection of these rights against piracy (Hadopi law), and finally the management perspectives of these rights by means of new legal licences controlled by companies in charge of collecting and distributing royalties (Sociétés de Perception et de Répartition des Droits - SPRD).Companies in Charge of Collecting and Distributing Royalties; Hadopi Laws; Intellectual Property; Legal Licences; Piracy; Protected Works

Solveurs linéaires scalables basés sur des sous--espaces de Krylov Élargis avec réduction dynamique des directions de recherche

Krylov methods are widely used for solving large sparse linear systems of equations.On distributed architectures, their performance is limited by the communication needed at eachiteration of the algorithm. In this paper, we study the use of so-called enlarged Krylov subspacesfor reducing the number of iterations, and therefore the overall communication, of Krylov methods.In particular, we consider a reformulation of the Conjugate Gradient method using these enlargedKrylov subspaces: the enlarged Conjugate Gradient method.We present the parallel design of two variants of the enlarged Conjugate Gradient method aswell as their corresponding dynamic versions where the number of search directions is dynamicallyreduced during the iterations. For a linear elasticity problem with heterogeneous coecients, usinga block Jacobi preconditioner, we show that this implementation scales up to 16; 384 cores, and isup to 5.7 times faster than the PETSc implementation of PCG.Les méthodes de Krylov sont largement utilisées pour résoudre les systèmes linéaires creux et de grande taille. Sur une architecture distribuée, leur performance est limitée par les communications nécessaires à chaque itération de l'algorithme. Dans ce papier, on étudie l'usage de sous{espaces de Krylov élargis pour réduire le nombre d'itérations, et ainsi le total des communications, des méthodes de Krylov. En particulier, on considère une reformulation de la méthode du Gradient Conjugué qui utilise ces sous{espaces de Krylov élargis :le Gradient Conjugué élargi.On présente le design parallèle de deux variantes de la méthode du Gradient Conjugué élargi ainsi que les versions dynamiques associées, où le nombre de directions de recherche est réduit dynamiquement pendant les itérations. Pour un problème d'élasticité linéaire avec des coefficients hétérogènes, en utilisant un preconditioneur de type Jacobi par bloc, on montre que cette implémentation passe à l'echelle jusquà 16; 384 coeurs, et est jusqu'à 5; 7 fois plus rapide que l'implémentation de PCG présente dans PETSc

Scalable Linear Solvers Based on Enlarged Krylov Subspaces with Dynamic Reduction of Search Directions

International audienceKrylov methods are widely used for solving large sparse linear systems of equations. On distributed architectures, their performance is limited by the communication needed at each iteration of the algorithm. In this paper, we study the use of so-called enlarged Krylov subspaces for reducing the number of iterations, and therefore the overall communication, of Krylov methods. In particular, we consider a reformulation of the conjugate gradient method using these enlarged Krylov subspaces: the enlarged conjugate gradient method. We present the parallel design of two variants of the enlarged conjugate gradient method, as well as their corresponding dynamic versions, where the number of search directions is dynamically reduced during the iterations. For a linear elasticity problem with heterogeneous coefficients, using a block Jacobi preconditioner, we show that this implementation scales up to 16,384 cores and is up to 6.9 times faster than the PETSc implementation of PCG

Réduction des coûts de communication et de calcul du Gradient Conjugué dans les sous-espaces de Krylov Élargi

In this paper we propose an algebraic method in order to reduce dynamically the number of search directions during block Conjugate Gradient iterations. Indeed, by monitoring the rank of the optimal step α k it is possible to detect inexact breakdowns and remove the corresponding search directions. We also propose an algebraic criterion that ensures in theory the equivalence between our method with dynamic reduction of the search directions and the classical block Conjugate Gradient. Numerical experiments show that the method is both stable, the number of iterations with or without reduction is of the same order, and effective, the search space is significantly reduced. We use this approach in the context of enlarged Krylov subspace methods which reduce communication when implemented on large scale machines. The reduction of the number of search directions further reduces the computation cost and the memory usage of those methods.Dans ce papier, nous proposons une méthode algébrique pour réduire dynamiquement le nombre de directions de recherche pendant les itérations du Gradient Conjugué par bloc. En effet, en mesurant la perte de rang numérique du pas optimal α k, il est possible d'enlever les directions de recherche superflues. Nous proposons aussi un critère algébrique qui assure en théorie l'équivalence entre notre méthode avec réduction dynamique des directions de recherche et le Gradient Conjugué par bloc classique. Les résultats numériques obtenus montrent que la méthode est à la fois stable, le nombre d'itérations est du même ordre avec ou sans la réduction, et efficace, l'espace de recherche est significativement réduit. Nous utilisons cette approche dans le contexte des méthodes de Krylov élargis qui réduisent les communications lorsqu'elles sont utilisées sur des machines parallèle à grande échelle. La réduction du nombre de directions de recherche réduit encore plus le coût de calcul et l'occupation mémoire de ces méthodes

BocopHJB 1.0.1 – User Guide

The original Bocop package implements a local optimization method. The optimal control problem is approximated by a finite dimensional optimization problem (NLP) using a time discretization (the direct transcription approach). The NLP problem is solved by the well known software Ipopt, using sparse exact derivatives computed by Adol-C. The second package BocopHJB implements a global optimization method. Similarly to the DynamicProgramming approach, the optimal control problem is solved in two steps. First we solve the Hamilton-Jacobi-Bellman equation satisfied by the value fonction of the problem. Then we simulate the optimal trajectory from any chosen initial condition. The computational effort is essentially taken by the first step, whose result, the value fonction, can be stored for subsequent trajectory simulations

New reactor dedicated to in operando studies of model catalysts by means of surface x-ray diffraction and grazing incidence small angle x-ray scattering

International audienceA new experimental setup has been developed to enable in situ studies of catalyst surfaces during chemical reactions by means of surface x-ray diffraction (SXRD) and grazing incidence small angle x-ray scattering. The x-ray reactor chamber was designed for both ultrahigh-vacuum (UHV) and reactive gas environments. A laser beam heating of the sample was implemented; the sample temperature reaches 1100 K in UHV and 600 K in the presence of reactive gases. The reactor equipment allows dynamical observations of the surface with various, perfectly mixed gases at controlled partial pressures. It can run in two modes: as a bath reactor in the pressure range of 1-1000 mbars and as a continuous flow cell for pressure lower than 10−3 mbar. The reactor is connected to an UHV preparation chamber also equipped with low energy electron diffraction and Auger spectroscopy. This setup is thus perfectly well suited to extend in situ studies to more complex surfaces, such as epitaxial films or supported nanoparticles. It offers the possibility to follow the chemically induced changes of the morphology, the structure, the composition, and growth processes of the model catalyst surface during exposure to reactive gases. As an example the Pd8Ni92(110) surface structure was followed by SXRD under a few millibars of hydrogen and during butadiene hydrogenation while the reaction was monitored by quadrupole mass spectrometry. This experiment evidenced the great sensitivity of the diffracted intensity to the subtle interaction between the surface atoms and the gas molecules

Genetic admixture between captive-bred and wild individuals affects patterns of dispersal in a brown trout (Salmo trutta) population

Genetic admixture between captive-bred and wild individuals has been demonstrated to affect many individual traits, although little is known about its potential influence on dispersal, an important trait governing the eco-evolutionary dynamics of populations. Here, we quantified and described the spatial distribution of genetic admixture in a brown trout (Salmo trutta) population from a small watershed that was stocked until 1999, and then tested whether or not individual dispersal parameters were related to admixture between wild and captive-bred fish. We genotyped 715 fish at 17 microsatellite loci sampled from both the mainstream and all populated tributaries, as well as 48 fish from the hatchery used to stock the study area. First, we used Bayesian clustering to infer local genetic structure and to quantify genetic admixture. We inferred first generation migrants to identify dispersal events and test which features (genetic admixture, sex and body length) affected dispersal parameters (i.e. probability to disperse, distance of dispersal and direction of the dispersal event). We identified two genetic clusters in the river basin, corresponding to wild fish on the one hand and to fish derived from the captive strain on the other hand, allowing us to define an individual gradient of admixture. Individuals with a strong assignment to the captive strain occurred almost exclusively in some tributaries, and were more likely to disperse towards a tributary than towards a site of the mainstream. Furthermore, dispersal probability increased as the probability of assignment to the captive strain increased, and individuals with an intermediate level of admixture exhibited the lowest dispersal distances. These findings show that various dispersal parameters may be biased by admixture with captive-bred genotypes, and that management policies should take into account the differential spread of captive-bred individuals in wild populations