21 research outputs found

    Color Categorization Independent of Color Naming

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    Color is continuous, yet we group colors into discrete categories associated with color names (e.g., yellow, blue). Color categorization is a case in point in the debate on how language shapes human cognition. Evidence suggests that color categorization depends on top-down input from the language system to the visual cortex. We directly tested this hypothesis by assessing color categorization in a stroke patient, RDS, with a rare, selective deficit in naming visually presented chromatic colors, and relatively preserved achromatic color naming. Multimodal MRI revealed a left occipito-temporal lesion that directly damaged left color-biased regions, and functionally disconnected their right-hemisphere homologs from the language system. The lesion had a greater effect on RDS’s chromatic color naming than on color categorization, which was relatively preserved on a nonverbal task. Color categorization and naming can thus be independent in the human brain, challenging the mandatory involvement of language in adult human cognition

    Modélisation grands signaux de convertisseurs à résonance série

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    The modelling of a resonant converter is quite difficult due to its periodic variable framework. The variation of its states implies a global nonlinear behavior. The model proposed in this paper is obtained by using the series expansion of the set of solution of the differential equations which describes the dynamic behavior of the converter. Once the method is introduced, it is applied to an example of a series resonant converter. Furthermore we show that the result can be extended to a family of converters. Experimental results are obtained and a comparison with the model actually in use is given. Finally, this model is applied to a stability analysis of this kind of converter.La modélisation des convertisseurs statiques à résonance est complexe car le circuit, de par sa topologie périodiquement modifiée au cours du fonctionnement, a un comportement global non linéaire. Le modèle proposé se base sur un développement harmonique à l'ordre supérieur au premier ordre, facile à mettre en œuvre et tenant compte du facteur d'amortissement du circuit oscillant. Ce modèle permet en outre l'étude dynamique du circuit. La méthode un fois introduite est appliquée sur un exemple de convertisseur à résonance série. A partir des résultats obtenus, le modèle est étendu à toute une classe de convertisseurs à résonance pour aboutir à un modèle général unique. Il est, par la suite, procédé à une validation expérimentale ainsi qu'à une comparaison avec le modèle classique du générateur de courant moyen équivalent. Cet article se termine par une application du modèle à l'analyse de la stabilité de ce type de convertisseur

    Approche dynamique du premier harmonique pour la modélisation de convertisseurs AC-AC à étage intermédiaire continu. Application aux générateurs à induction

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    In this paper, we present a modelling technique for power electronics converters with both DC and AC stages. This technique is based on a dynamical approach of the first harmonic method. The approach is first applied to an idealized converter and second is extended to a framework working under discontinuous conduction mode. At the end, comparative simulations are done to validate the continuous built model.Dans cet article, il est présenté une technique de modélisation de convertisseurs présentant à la fois des étages continus et alternatifs. Cette technique est basée sur une approche dynamique de la méthode du premier harmonique. La technique est tout d'abord appliquée à un convertisseur idéalisé pour être ensuite étendue à une structure travaillant en conclusion discontinue. En dernier lieu, des simulations viennent valider le modèle continu mis au point

    Optimization of a DCDC Dual Active Bridge Converter for Aircraft Application

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    Galvanically isolated differential data transmission using capacitive coupling and a modified Manchester algorithm for smart power converters

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    In this paper, a method for encoding and decoding digital data signals using a modified form of the standard Manchester code for the application in galvanically isolated data transmission in smart power electronics is described. The method includes a modified encoder circuit and a matching decoder circuit that is able to rebuild the original clock and data signal without a separate transmission of the clock signal. A capacitive coupling element with a corresponding signal conditioning circuit was placed between the encoder and decoder circuit to achieve a galvanic isolation between the primary side that processes the data signals and the secondary side that is responsible for the processing of power in smart power devices. After a description of basic principles of the transmission of data over a galvanic isolation and the state-of-the-art of Manchester code based data transmission, the encoding and decoding process of the modified Manchester code is elaborated and experimental results are presented
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