87 research outputs found

    Hybrid power generation system for aircraft electrical emergency network

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    A whole structure and two management strategies are proposed here for hybridisation of a Ram air turbine (RAT) by means of supercapacitors. Such hybrid structure is dedicated to an aircraft emergency network. The structure consists in coupling, through a 270 V DC bus, a controlled source (RAT) with a storage device interfaced through a bidirectional DC–DC converter. Both the energy-management strategies are described and analysed: the first one is to assign the ‘high-frequency harmonics’ of the load power to the storage which is current controlled, whereas the RAT controls the bus voltage and then only feeds the average power, losses and low-frequency harmonics of the load. The second one proposes an energy optimised operation of the system: the RAT, being current controlled, is able to maximise the supplied power (maximum power point tracking), as for classical wind turbines. For such a strategy, the bus voltage is regulated from the storage device. The RAT sizing and its mass can then be strongly reduced by means of this hybrid structure controlled with optimised management strategies. Experiments on a lab test-bench confirm analyses presented

    Innovations en milieu de travail dans le secteur manufacturier au Québec

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    Sur la base d'un sondage téléphonique mené auprès de la direction des établissements manufacturiers de 50 employés et plus au Québec, cette contribution se penche sur la diffusion des innovations organisationnelles. Les résultats présentés sont organisés autour de cinq configurations de changements, se distinguant par une logique organisationnelle spécifique, à laquelle sont associées des performances économiques et sociales ainsi que des pratiques de gestion des ressources humaines et de relations de travail. Ils confirment l'émergence d'un nouveau paradigme technico-productif, sans qu'il soit possible de conclure à une véritable transformation du travail, étant donné la faible diffusion des configurations participatives, qui affichent néanmoins les meilleures performances, en s'appuyant sur les pratiques de ressources humaines et de relations de travail les plus novatrices

    Reflective Model Driven Engineering

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    In many large organizations, the model transformations allowing the engineers to more or less automatically go from platformindependent models (PIM) to platform-specific models (PSM) are increasingly seen as vital assets. As tools evolve, it is critical that these transformations are not prisoners of a given CASE tool. Considering in this paper that a CASE tool can be seen as a platform for processing a model transformation, we propose to reflectively apply the MDA to itself. We propos

    Social support, but not perceived food environment, is associated with diet quality in French-speaking Canadians from the PREDISE study

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    The objectives were to assess whether social support for healthy eating and perceived food environment are associated with diet quality, and to investigate if sociodemographic characteristics moderate these associations. A probability sample of French-speaking adults from the Province of Québec, Canada, was recruited in the context of the PREDISE study. Participants reported their perceptions of supportive and non-supportive actions related to healthy eating from close others at home and outside of home (n = 952), and of the accessibility to healthy foods (n = 1035). The Canadian Healthy Eating Index (C-HEI) was calculated based on three Web-based 24 h food recalls. Multiple linear regression models showed that supportive (B = 1.50 (95% CI 0.46, 2.54)) and non-supportive (B = −3.06 (95% CI −4.94, −1.18)) actions related to healthy eating from close others at home were positively and negatively associated with C-HEI, respectively, whereas actions from close others outside of home were not. The negative association between non-supportive actions occurring at home and C-HEI was stronger among participants with lower (vs. higher) levels of education (p interaction = 0.03). Perceived accessibility to healthy foods was not associated with C-HEI (p > 0.05). These results suggest that the social environment may have a stronger influence on healthy eating than the perceived physical environment. This adds support for healthy eating promotion programs involving entire families, especially for more socioeconomically disadvantaged individuals, whose efforts to eat healthily may be more easily thwarted by non-supportive household

    Planck 2013 results. XXII. Constraints on inflation

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    We analyse the implications of the Planck data for cosmic inflation. The Planck nominal mission temperature anisotropy measurements, combined with the WMAP large-angle polarization, constrain the scalar spectral index to be ns = 0:9603 _ 0:0073, ruling out exact scale invariance at over 5_: Planck establishes an upper bound on the tensor-to-scalar ratio of r < 0:11 (95% CL). The Planck data thus shrink the space of allowed standard inflationary models, preferring potentials with V00 < 0. Exponential potential models, the simplest hybrid inflationary models, and monomial potential models of degree n _ 2 do not provide a good fit to the data. Planck does not find statistically significant running of the scalar spectral index, obtaining dns=dln k = 0:0134 _ 0:0090. We verify these conclusions through a numerical analysis, which makes no slowroll approximation, and carry out a Bayesian parameter estimation and model-selection analysis for a number of inflationary models including monomial, natural, and hilltop potentials. For each model, we present the Planck constraints on the parameters of the potential and explore several possibilities for the post-inflationary entropy generation epoch, thus obtaining nontrivial data-driven constraints. We also present a direct reconstruction of the observable range of the inflaton potential. Unless a quartic term is allowed in the potential, we find results consistent with second-order slow-roll predictions. We also investigate whether the primordial power spectrum contains any features. We find that models with a parameterized oscillatory feature improve the fit by __2 e_ _ 10; however, Bayesian evidence does not prefer these models. We constrain several single-field inflation models with generalized Lagrangians by combining power spectrum data with Planck bounds on fNL. Planck constrains with unprecedented accuracy the amplitude and possible correlation (with the adiabatic mode) of non-decaying isocurvature fluctuations. The fractional primordial contributions of cold dark matter (CDM) isocurvature modes of the types expected in the curvaton and axion scenarios have upper bounds of 0.25% and 3.9% (95% CL), respectively. In models with arbitrarily correlated CDM or neutrino isocurvature modes, an anticorrelated isocurvature component can improve the _2 e_ by approximately 4 as a result of slightly lowering the theoretical prediction for the ` <_ 40 multipoles relative to the higher multipoles. Nonetheless, the data are consistent with adiabatic initial conditions

    Sampling mobile oceanic fishes and sharks: implications for fisheries and conservation planning

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    Tuna, billfish, and oceanic sharks [hereafter referred to as ‘mobile oceanic fishes and sharks’ (MOFS)] are characterised by conservative life-history strategies and highly migratory behaviour across large, transnational ranges. Intense exploitation over the past 65 years by a rapidly expanding high-seas fishing fleet has left many populations depleted, with consequences at the ecosystem level due to top-down control and trophic cascades. Despite increases in both CITES and IUCN Red Listings, the demographic trajectories of oceanic sharks and billfish are poorly quantified and resolved at geographic and population levels. Amongst MOFS trajectories, those of tunas are generally considered better understood, yet several populations remain either overfished or of unknown status. MOFS population trends and declines therefore remain contentious, partly due to challenges in deriving accurate abundance and biomass indices. Two major management strategies are currently recognised to address conservation issues surrounding MOFS: (i) internationally ratified legal frameworks and their associated regional fisheries management organisations (RFMOs); and (ii) spatio-temporal fishery closures, including no-take marine protected areas (MPAs). In this context, we first review fishery-dependent studies relying on data derived from catch records and from material accessible through fishing extraction, under the umbrella of RFMO-administrated management. Challenges in interpreting catch statistics notwithstanding, we find that fishery-dependent studies have enhanced the accuracy of biomass indices and the management strategies they inform, by addressing biases in reporting and non-random effort, and predicting drivers of spatial variability across meso- and oceanic scales in order to inform stock assessments. By contrast and motivated by the increase in global MPA coverage restricting extractive activities, we then detail ways in which fishery-independent methods are increasingly improving and steering management by exploring facets of MOFS ecology thus far poorly grasped. Advances in telemetry are increasingly used to explore ontogenic and seasonal movements, and provide means to consider MOFS migration corridors and residency patterns. The characterisation of trophic relationships and prey distribution through biochemical analysis and hydro-acoustics surveys has enabled the tracking of dietary shifts and mapping of high-quality foraging grounds. We conclude that while a scientific framework is available to inform initial design and subsequent implementation of MPAs, there is a shortage in the capacity to answer basic but critical questions about MOFS ecology (who, when, where?) required to track populations non-extractively, thereby presenting a barrier to assessing empirically the performance of MPA-based management for MOFS. This sampling gap is exacerbated by the increased establishment of large (>10000 km2) and very large MPAs (VLMPAs, >100000 km2) - great expanses of ocean lacking effective monitoring strategies and survey regimes appropriate to those scales. To address this shortcoming, we demonstrate the use of a non-extractive protocol to measure MOFS population recovery and MPA efficiency. We further identify technological avenues for monitoring at the VLMPA scale, through the use of spotter planes, drones, satellite technology, and horizontal acoustics, and highlight their relevance to the ecosystem-based framework of MOFS management

    Planck 2015 results. XX. Constraints on inflation

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    We present the implications for cosmic inflation of the Planck measurements of the cosmic microwave background (CMB) anisotropies in both temperature and polarization based on the full Planck survey. The Planck full mission temperature data and a first release of polarization data on large angular scales measure the spectral index of curvature perturbations to be n s = 0.968 ± 0.006 and tightly constrain its scale dependence to dn s /dlnk = −0.003 ± 0.007 when combined with the Planck lensing likelihood. When the high-ℓ polarization data is included, the results are consistent and uncertainties are reduced. The upper bound on the tensor-to-scalar ratio is r 0.002 <0.11 (95% CL), consistent with the B-mode polarization constraint r<0.12 (95% CL) obtained from a joint BICEP2/Keck Array and Planck analysis. These results imply that V(ϕ)∝ϕ 2 and natural inflation are now disfavoured compared to models predicting a smaller tensor-to-scalar ratio, such as R 2 inflation. Three independent methods reconstructing the primordial power spectrum are investigated. The Planck data are consistent with adiabatic primordial perturbations. We investigate inflationary models producing an anisotropic modulation of the primordial curvature power spectrum as well as generalized models of inflation not governed by a scalar field with a canonical kinetic term. The 2015 results are consistent with the 2013 analysis based on the nominal mission data

    MDSOFA: A MODEL-DRIVEN SOFTWARE FACTORY

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    A major issue in software engineering is software production improvement. This paper studies the objectives and the features of a model-driven software factory contributing to automate the production of software systems in evolving environments (specifications, standards, technology, and tools). Through these considerations, this paper introduces MDSoFa, a Model-Driven SOftware FActory tool developed at THALES meeting this need, and a set of technical and methodological lessons learned from this tool implementation and usage. 1

    Facteurs déterminant la prescription de la pompe à proton en médecine générale

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    Les inhibiteurs de la pompe à protons (IPP) sont une des classes thérapeutiques les plus prescrites en médecine générale. Des recommandations de bonnes pratiques (RBP) précises existent, et certains cas de mésusage ont été mis en évidence par plusieurs études. en revanche peu d'études ont recherché les facteurs qui conduisent un médecin généraliste à prescrire des IPP. l'objectif de cette étude était de mettre en évidence les facteurs déterminant la prescription d'IPP en médecine générale. Il s'agit d'une recherche qualitative à partir d'entretiens semi-dirigés auprès de 12 médecins généralistes du Puy-de-Dôme. Verbatim intégralement retranscrit, puis "découpé" et classé par thèmes pour faciliter le codage. Les médecins généralistes ont décrit les RBP comme un guide, mais reconnaissent avoir certaines difficultés à les appliquer au quotidien. Plusieurs facteurs étaient fréquemment retrouvés comme favorisants la prescription d'IPP : la pression du patient, le manque de temps, la difficulté à arrêter un traitement initié par un confrère surtout hospitalier ou gastroentérologue. Les interventions des délégués de l'assurance maladie étaient en général décrites comme utiles. Elles étaient le seul facteur retrouvé à l'origine de non prescription. Mais leur but économique était souvent remis en cause par les médecins. Les visites des délégués médicaux de l'industrie pharmaceutique étaient décrites comme ayant peu d'impact sur la prescription par les généralistes qui les recevaient, mais comme ayant une influence par les généralistes qui ne les recevaient plus. Ce travail reflète la multiplicité des facteurs déterminant la prescription d'IPP en médecine générale. Une étude évaluant l'impact d'une action de formation sur les prescriptions inadéquates d'IPP par les médecins généralistes serait intéressante à mener.CLERMONT FD-BCIU-Santé (631132104) / SudocSudocFranceF
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