80 research outputs found

    Predicting dengue fever outbreaks in French Guiana using climate indicators

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    Background Dengue fever epidemic dynamics are driven by complex interactions between hosts, vectors and viruses. Associations between climate and dengue have been studied around the world, but the results have shown that the impact of the climate can vary widely from one study site to another. In French Guiana, climate-based models are not available to assist in developing an early warning system. This study aims to evaluate the potential of using oceanic and atmospheric conditions to help predict dengue fever outbreaks in French Guiana. Methodology/Principal Findings Lagged correlations and composite analyses were performed to identify the climatic conditions that characterized a typical epidemic year and to define the best indices for predicting dengue fever outbreaks during the period 1991-2013. A logistic regression was then performed to build a forecast model. We demonstrate that a model based on summer Equatorial Pacific Ocean sea surface temperatures and Azores High sea-level pressure had predictive value and was able to predict 80% of the outbreaks while incorrectly predicting only 15% of the non-epidemic years. Predictions for 2014-2015 were consistent with the observed non-epidemic conditions, and an outbreak in early 2016 was predicted. Conclusions/Significance These findings indicate that outbreak resurgence can be modeled using a simple combination of climate indicators. This might be useful for anticipating public health actions to mitigate the effects of major outbreaks, particularly in areas where resources are limited and medical infrastructures are generally insufficient

    Turbo décodage de code produit haut débit utilisant un code BCH étendu (128,106,8) t=3

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    - Cet article propose une nouvelle architecture de turbo dĂ©codage de codes BCH (128,106,8) Ă  entrĂ©es et sorties pondĂ©rĂ©es corrigeant 3 erreurs. En utilisant le concept de parallĂ©lisme et les propriĂ©tĂ©s de la matrice gĂ©nĂ©rĂ©e par un code produit, cet article prĂ©sente la conception et la complexitĂ© de trois dĂ©codeurs capables de traiter 2, 4 et 8 donnĂ©es en mĂȘme temps pour obtenir le haut dĂ©bit dans le dĂ©codage. Pour comparer les performances et la complexitĂ© entre les diffĂ©rents dĂ©codeurs, le langage C a Ă©tĂ© utilisĂ© pour les simulations, le langage VHDL pour les simulations fonctionnelles et Synopsys Design Compiler pour la synthĂšse. Les rĂ©sultats ainsi obtenus ouvrent la possibilitĂ© d'intĂ©gration sur le silicium de turbo dĂ©codeurs Ă  fort pouvoir de correction (distance de 64, rendement de 0,8) et Ă  haut dĂ©bit (6,4Gbits/s)

    High frequency properties of Si/SiGe n-MODFETs: dependence on gate length and temparture

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    The HF performances of n-type strained Si channel Modulation Doped Field Effect Transistors (MODFETs) with 0.118 ”m, 0.130 ”m and 0.250 ”m gate lengths are reported at 300 K and 50 K. At 300K, intrinsic cut-off frequencies fTi are 65 GHz, 58 GHz, 37 GHz and maximum oscillation frequencies fMAX are 76 GHz ,60 GHz, and 100 GHz , respectively. The 0.130 ”m device presents at 300 K a record intrinsic transconductance of 715 mS/mm and excellent noise performances with a de-embedded Minimum Noise Figure NFmin of 0.3 dB at 2.5 GHz. The variation of fMAX underlines the importance of the device parasitic resistances

    Ping-pong supervisor for synchronous links

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    ModĂšle analytique du MESFET AsGa pour simulation de circuits logiques ultra-rapides

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    A model of the GaAs MESFET is developped for the design of picosecond circuits at the MSI or LSI level. The parameter description is optimized both for dynamic response and computer time efficiency. The model is implemented in the time simulator MACPRO designed for the analysis of propagation and coupling effects in very fast integrated circuits. The model is fully presented and validated against both experimental I-V curves and microwave S parameters measurements of a single MESFET, and analog dynamic response of a BFL ring oscillator. The influence of the main model parameters on the circuit dynamic response is discussed relatively to a BFL technology.Un modÚle de MESFET AsGa est développé pour la conception des circuits logiques picosecondes à moyenne et grande intégration. La formulation des paramÚtres du modÚle est optimisée à la fois pour un bon comportement dynamique des portes logiques et pour une grande efficacité en temps de calcul. Ce modÚle est implanté sur le macro-simulateur MACPRO qui a été conçu pour l'étude des effets de propagation et de couplage dans les circuits intégrés ultrarapides. Le modÚle est présenté de façon exhaustive et il est comparé à des mesures statiques (caractéristiques I-V de transistors hyperfréquence) et dynamiques (comportement en paramÚtres S d'un MESFET hyperfréquence, oscillateur en anneau en technologie BFL). La derniÚre partie de l'article étudie l'influence des paramÚtres importants de ce modÚle sur le régime transitoire des portes logiques BFL

    Introduction to Digital Integrated Circuit Design

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    International audienc
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