33 research outputs found

    Homogenization of a model for the propagation of sound in the lungs

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    International audienceIn this paper, we are interested in the mathematical modeling of the propagation of sound waves in the lung parenchyma, which is a foam-like elastic material containing millions of air-filled alveoli. In this study, the parenchyma is governed by the linearized elasticity equations, and the air by the acoustic wave equations. The geometric arrangement of the alveoli is assumed to be periodic with a small period Δ > 0. We consider the time-harmonic regime forced by vibrations induced by volumic forces. We use the two-scale convergence theory to study the asymptotic behavior as Δ goes to zero and prove the convergence of the solutions of the coupled fluid-structure problem to the solution of a linear-elasticity boundary value problem

    The Movement Imagery Questionnaire-Revised, Second Edition (MIQ-RS) Is a Reliable and Valid Tool for Evaluating Motor Imagery in Stroke Populations

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    Mental imagery can improve motor performance in stroke populations when combined with physical therapy. Valid and reliable instruments to evaluate the imagery ability of stroke survivors are needed to maximize the benefits of mental imagery therapy. The purposes of this study were to: examine and compare the test-retest intra-rate reliability of the Movement Imagery Questionnaire-Revised, Second Edition (MIQ-RS) in stroke survivors and able-bodied controls, examine internal consistency of the visual and kinesthetic items of the MIQ-RS, determine if the MIQ-RS includes both the visual and kinesthetic dimensions of mental imagery, correlate impairment and motor imagery scores, and investigate the criterion validity of the MIQ-RS in stroke survivors by comparing the results to the KVIQ-10. Test-retest analysis indicated good levels of reliability (ICC range: .83–.99) and internal consistency (Cronbach α: .95–.98) of the visual and kinesthetic subscales in both groups. The two-factor structure of the MIQ-RS was supported by factor analysis, with the visual and kinesthetic components accounting for 88.6% and 83.4% of the total variance in the able-bodied and stroke groups, respectively. The MIQ-RS is a valid and reliable instrument in the stroke population examined and able-bodied populations and therefore useful as an outcome measure for motor imagery ability

    SABRE: A bio-inspired fault-tolerant electronic architecture

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    As electronic devices become increasingly complex, ensuring their reliable, fault-free operation is becoming correspondingly more challenging. It can be observed that, in spite of their complexity, biological systems are highly reliable and fault tolerant. Hence, we are motivated to take inspiration for biological systems in the design of electronic ones. In SABRE (self-healing cellular architectures for biologically inspired highly reliable electronic systems), we have designed a bio-inspired fault-tolerant hierarchical architecture for this purpose. As in biology, the foundation for the whole system is cellular in nature, with each cell able to detect faults in its operation and trigger intra-cellular or extra-cellular repair as required. At the next level in the hierarchy, arrays of cells are configured and controlled as function units in a transport triggered architecture (TTA), which is able to perform partial-dynamic reconfiguration to rectify problems that cannot be solved at the cellular level. Each TTA is, in turn, part of a larger multi-processor system which employs coarser grain reconfiguration to tolerate faults that cause a processor to fail. In this paper, we describe the details of operation of each layer of the SABRE hierarchy, and how these layers interact to provide a high systemic level of fault tolerance. © 2013 IOP Publishing Ltd

    De l'effet destructeur d'un arrĂȘt d'annulation sur des mesures non querellĂ©es, observations sous Conseil d'Etat, n° 19.250, 14 novembre 1978, Janssens et crts

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    SOMMAIRE : I. Les faits prĂ©alables Ă  l'arrĂȘt du 14 novembre 1978 / II. De l'effet de l'annulation d'une disposition rĂ©glementaire sur ses mesures d'application / III. Des recours querellant des mesures d'application d'une disposition rĂ©glementaire annulĂ©

    On transistor level gate sizing for increased robustness to transient faults

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    In this paper we present a detailed analysis on how the critical charge (Q crit) of a circuit node, usually employed to evaluate the probability of transient fault (TF) occurrence as a consequence of a particle hit, depends on transistors' sizing. We derive an analytical model allowing us to calculate a node's Q crit given the size of the node's driving gate and fan-out gate(s), thus avoiding time costly electrical level simulations. We verified that such a model features an accuracy of the 97% with respect to electrical level simulations performed by HSPICE. Our proposed model shows that Q crit depends much more on the strength (conductance) of the gate driving the node, than on the node total capacitance. We also evaluated the impact of increasing the conductance of the driving gate on TFs' propagation, hence on Soft Error Susceptibility (SES). We found that such a conductance increase not only improves the TF robustness of the hardened node, but also that of the whole circuit. © 2005 IEEE

    Accurate linear model for SET critical charge estimation

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    In this paper, we present an accurate linear model for estimating the minimum amount of collected charge due to an energetic particle striking a combinational circuit node that may give rise to a SET with an amplitude larger than the noise margin of the subsequent gates. This charge value will be referred to as SET critical charge (Q-SET}). Our proposed model allows to calculate the Q-SET} of a node as a function of the size of the transistors of the gate driving the node and the fan-out gate(s), with no need for time costly electrical level simulations. This makes our approach suitable to be integrated into a design automation tool for circuit radiation hardening. The proposed model features 96% average accuracy compared to electrical level simulations performed by HSPICE. Additionally, it highlights that Q-SET} has a much stronger dependence on the strength of the gate driving the node, than on the node total capacitance. This property could be considered by robust design techniques in order to improve their effectiveness. © 2006 IEEE

    Carte générale des sondes dŽattérages des cÎtes occidentales de France et des cÎtes septentrionales dŽEspagne faites, en 1828 et 1829

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    Na parte inferior dereita, selo gravado con anclaInsire: tres perfís topogråficos de 3 x 45 cm, ou menos e unha advertenciaReproducción electrónica. Santiago de Compostela : Biblioteca de Galicia, 2009Meridiano de referencia París. Marxes graduadas. Toponimia localizada na costa. Sondas batimétrica
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