RBF neural net based classifier for the AIRIX accelerator fault diagnosis

The AIRIX facility is a high current linear accelerator (2-3.5kA) used for flash-radiography at the CEA of Moronvilliers France. The general background of this study is the diagnosis and the predictive maintenance of AIRIX. We will present a tool for fault diagnosis and monitoring based on pattern recognition using artificial neural network. Parameters extracted from the signals recorded on each shot are used to define a vector to be classified. The principal component analysis permits us to select the most pertinent information and reduce the redundancy. A three layer Radial Basis Function (RBF) neural network is used to classify the states of the accelerator. We initialize the network by applying an unsupervised fuzzy technique to the training base. This allows us to determine the number of clusters and real classes, which define the number of cells on the hidden and output layers of the network. The weights between the hidden and the output layers, realising the non-convex union of the clusters, are determined by a least square method. Membership and ambiguity rejection enable the network to learn unknown failures, and to monitor accelerator operations to predict future failures. We will present the first results obtained on the injector.Comment: 3 pages, 4 figures, LINAC'2000 conferenc

Observatoires du développement, observatoires pour le développement

Le cas des migrations clandestines internationales éclaire le conflit entre les définitions de l'espace et du temps des acteurs et des analystes. La relativité des distinctions spatiales officielles s'allie à la relativité de la durée ou de la récurrence des migrations pour faire que mesurer les migrations et retrouver les migrants constituent des tâches distinctes. On retrouve donc ici la richesse du contraste entre les définitions objectives et subjectives du continuum spatio-temporel et la nécessité d'adapter l'instrument aux propriétés spécifiques du phénomène dont on veut rendre compte. De là, la complexité de la distinction entre les notions de territoire et de réseau, ou encore entre les notions de temps universel et de cycle de vie. Il en résulte qu'une analyse ne peut donner des résultats précis que si elle repose sur des modes différenciés, les uns privilégiant les inventaires, les autres les flux et que si elle implique le mélange de données venant de sources distinctes. L'adaptation d'instruments de mesure aux variations de durée, de direction, d'étapes intermédiaires et de taille des unités migrantes représente une innovation susceptible d'être généralisée à d'autres contextes. (Résumé d'auteur

L’évolution du taux de la plus-value en France (1951-1980)

The measurement of the rate of surplus-value, in France, during the last thirty years, refers to the Marxist economic theory of capitalism and araises theoretical and statistical problems.

Light Non-degenerate Composite Partners at the LHC

We study the implications of a large degree of compositeness for the light generation quarks in composite pseudo-Nambu-Goldstone-boson Higgs models. We focus in particular on viable scenarios where the right-handed up-type quarks have a sizable mixing with the strong dynamics. For concreteness we assume the latter to be characterized by an SO(5)/SO(4) symmetry with fermionic resonances in the SO(4) singlet and fourplet representations. Singlet partners dominantly decay to a Higgs boson and jets. As no dedicated searches are currently looking for these final states, singlet partners can still be rather light. Conversely, some fourplet partners dominantly decay to an electroweak gauge boson and a jet, a signature which has been analyzed at the LHC. To constrain the parameter space of this scenario we have reinterpreted various LHC analyses. In the limit of first two generation degeneracy, as in minimal flavor violation or U(2)-symmetric flavor models, fourplet partners need to be relatively heavy, with masses above 1.8 TeV, or the level of compositeness needs to be rather small. The situation is rather different in models that deviate from the first two generation degeneracy paradigm, as the charm parton distribution functions are suppressed relative to the up quark ones. The right-handed charm quark can be composite and its partners being as light as 600 GeV, while the right-handed up quark needs either to be mostly elementary or to have its partners as heavy as 2 TeV. Models with fully composite singlet fermions are also analyzed, leading to similar conclusions. Finally, we consider the case where both the fourplet and the singlet states are present. In this case the bounds could be significantly weaken due to a combination of smaller production rates and the opening of new channels including cascade processes.Comment: 49 pages, 18 figure

Proof of the Double Bubble Conjecture in R^n

The least-area hypersurface enclosing and separating two given volumes in R^n is the standard double bubble.Comment: 20 pages, 22 figure

L’évolution du taux de la plus-value en France (1951-1980)

The measurement of the rate of surplus-value, in France, during the last thirty years, refers to the Marxist economic theory of capitalism and araises theoretical and statistical problems. From a theoretical point of view and after discussing on the legitimacy of measuring the rate of surplus-value, the author mainly evocates the following problems. 1) what kind of workers generate surplus-value? 2) are engineers producers of surplus-value? 3) is it correct to use the data of national accounts to quantify a rate defined on an essential level? After mentioning the theoretical choices, the author examines the statistical aspects of the problems. According to his results and assumptions, his main conclusion is that the rate of surplus-value, in France, has grown up from 1950. But its rate has been getting slower and slower. The return of capitalist exploitation would have been decreasing. The economic policy worked out from 1974 to 1980 resulted in an increase of the rate of surplus-value without reaching the variations observed during the Vth Républic