Evaluation of cross-layer reliability mechanisms for satellite digital multimedia broadcast

This paper presents a study of some reliability mechanisms which may be put at work in the context of Satellite Digital Multimedia Broadcasting (SDMB) to mobile devices such as handheld phones. These mechanisms include error correcting codes, interleaving at the physical layer, erasure codes at intermediate layers and error concealment on the video decoder. The evaluation is made on a realistic satellite channel and takes into account practical constraints such as the maximum zapping time and the user mobility at several speeds. The evaluation is done by simulating different scenarii with complete protocol stacks. The simulations indicate that, under the assumptions taken here, the scenario using highly compressed video protected by erasure codes at intermediate layers seems to be the best solution on this kind of channel

Devenir, former, recruter un géomaticien : Petit guide pratique de la géomatique à destination des employeurs, des candidats et des formateurs

Document pdf disponible sur le site de l'AFIGEOPublié à l'occasion du Colloque national " Métiers et compétences en géomatique : des formations aux emplois " le 14 novembre 2013 au CNAM, ce guide est le fruit d'une réflexion collective menée au sein du Pôle Formation-Recherche de l'AFIGEO. S'appuyant sur de nombreuses ressources (issues des résultats d'une enquête métier réalisée en 2013 avec GeoRezo et le GDR Magis, d'analyse de fiches de poste, de l'observatoire des GeoFormations, de la démarche de reconnaissance des métiers), il s'organise autour de 4 chapitres : - QU'EST-CE QUE LA GEOMATIQUE ? - A QUOI SERT UN GEOMATICIEN ? - SE FORMER A LA GEOMATIQUE ? - RECRUTER UN GEOMATICIEN ? En s'adressant aux étudiants, formateurs, recruteurs, géomaticiens débutants ou plus expérimentés, ce guide vise à apporter un éclairage pédagogique, concret sur le vaste monde de la géomatique, sur les spécificités des compétences, des métiers et des formations associés. Pour recevoir la version numérique du Guide, nous vous remercions de compléter le formulaire de demande suivant : https://docs.google.com/forms/d/1MYxjzslEeLd4VwsdOKwtxJyZwVLaLNv7d_lBj_mPGlM/viewfor

SCCO: Thermodiffusion for the Oil and Gas Industry

International audienc

The BLLAST field experiment: Boundary-Layer late afternoon and sunset turbulence

Due to the major role of the sun in heating the earth's surface, the atmospheric planetary boundary layer over land is inherently marked by a diurnal cycle. The afternoon transition, the period of the day that connects the daytime dry convective boundary layer to the night-time stable boundary layer, still has a number of unanswered scientific questions. This phase of the diurnal cycle is challenging from both modelling and observational perspectives: it is transitory, most of the forcings are small or null and the turbulence regime changes from fully convective, close to homogeneous and isotropic, toward a more heterogeneous and intermittent state. These issues motivated the BLLAST (Boundary-Layer Late Afternoon and Sunset Turbulence) field campaign that was conducted from 14 June to 8 July 2011 in southern France, in an area of complex and heterogeneous terrain. A wide range of instrumented platforms including full-size aircraft, remotely piloted aircraft systems, remote-sensing instruments, radiosoundings, tethered balloons, surface flux stations and various meteorological towers were deployed over different surface types. The boundary layer, from the earth's surface to the free troposphere, was probed during the entire day, with a focus and intense observation periods that were conducted from midday until sunset. The BLLAST field campaign also provided an opportunity to test innovative measurement systems, such as new miniaturized sensors, and a new technique for frequent radiosoundings of the low troposphere. Twelve fair weather days displaying various meteorological conditions were extensively documented during the field experiment. The boundary-layer growth varied from one day to another depending on many contributions including stability, advection, subsidence, the state of the previous day's residual layer, as well as local, meso- or synoptic scale conditions. Ground-based measurements combined with tethered-balloon and airborne observations captured the turbulence decay from the surface throughout the whole boundary layer and documented the evolution of the turbulence characteristic length scales during the transition period. Closely integrated with the field experiment, numerical studies are now underway with a complete hierarchy of models to support the data interpretation and improve the model representations.publishedVersio

Polesat-web-2018: a simulation it tool with immediate prospective and strategic views of hospital spatial planning

International audienceMedical geo-informatics allows the Health world to address major challenges thanks to attractive concepts, methods and user-friendly IT. PoleSat-web-2018 presents a decision support system - a modelling "variable geometry" IT tool for simulation of hospital spatial planning. The outputs enable quasi-instantaneous analytic visualization at several geographic levels. PoleSat-web-2018 provides prospective views of hospital catchments (by grouping, closing) and proves to be relevant for the French planners of the Ministry of Health