Robotics and neuroscience: A rhythmic interaction

At the crossing between motor control neuroscience and robotics system theory, the paper presents a rhythmic experiment that is amenable both to handy laboratory implementation and simple mathematical modeling. The experiment is based on an impact juggling task, requiring the coordination of two upper-limb effectors and some phase-locking with the trajectories of one or several juggled objects. We describe the experiment, its implementation and the mathematical model used for the analysis. Our underlying research focuses on the role of sensory feedback in rhythmic tasks. In a robotic implementation of our experiment, we study the minimum feedback that is required to achieve robust control. A limited source of feedback, measuring only the impact times, is shown to give promising results. A second field of investigation concerns the human behavior in the same impact juggling task. We study how a variation of the tempo induces a transition between two distinct control strategies with different sensory feedback requirements. Analogies and differences between the robotic and human behaviors are obviously of high relevance in such a flexible setup

La base de données HelioClim de rayonnement solaire disponible au sol

La ressource solaire disponible au sol est devenue un enjeu majeur dans les nouvelles technologies de développement durable. Les utilisateurs publics et privés de l'énergie solaire ont besoin d'un accès facile et rapide à cette information, sous forme ponctuelle ou sous forme de cartes à l'échelle locale, régionale, ou nationale. Les images satellitaires apparaissent comme les mieux appropriées pour couvrir une grille d'échantillonnage de haute résolution, régulière dans l'espace et dans le temps. Les stations de mesures au sol n'offrent en effet pas ces avantages : répartition irrégulière nécessitant des interpolations ou extrapolations qui diminuent la précision du résultat, dates de mises en service différentes, format des données et unités de mesure non standardisés, accès aux données non centralisé et le plus souvent sous forme non adaptée aux besoins des utilisateurs, rendant finalement leur coût assez important. Mines ParisTech apporte une réponse innovante aux besoins des utilisateurs, d'une part dès 1986 en développant la famille de méthodes Heliosat qui permettent de convertir des images de satellites géostationnaires en carte de rayonnement global incident au sol, d'autre part en implémentant une chaine de traitement opérationnelle en temps réel entre la réception de l'image, son traitement par Heliosat-2, et son exploitation dans le système de base de données HelioClim

Tool to design the primary electrical insulation system of low voltage rotating machines fed by inverters

International audienceIn this communication, we describe a methodologic tool (software) that give instruction to design the coil winding of low voltage machines fed by inverters. The aim of this tool is to bring useful information to the coil manufacturer who has, first, to respect the size of the slots, the total copper section (slot occupancy) and the coil voltage that are imposed by the motor designer. Then, to increase the PDIV between turns and between turns and ground to the highest value. For that purpose, by using a numerical simulation that takes into account the Paschen's law, the developed software will provide how to choose and arrange the enameled wires in the slots: random or form-wound coils, wires shape (round or rectangular), number of wires in parallel by turn, insulation thickness (grade), turns arrangement,... up to find the best solution that allow to respect both motor designer and PDIV constraints. Some practical examples will be given to prove the efficiency of such a tool

Twelve monthly maps of ground albedo parameters derived from MODIS data sets

International audienceThe National Aeronautics and Space Administration (NASA) of the USA is making available to anyone worldwide maps of ground albedo parameters that are derived from the MODIS (Moderate Resolution Imaging Spectroradiometer) instrument. The first parameter fiso describes the isotropic part of the bidirectional reflectance distribution function (BRDF); the two other parameters fvol and fgeo are linked to the viewing and illuminating geometry and describe the anisotropic part of the BRDF. These maps exhibit missing values. This communication describes a series of 12 monthly maps of the BRDF parameters with no missing values available on the Web. In addition, a method for computing the ground albedo is proposed that does not require the a priori knowledge of the ratio of the direct to the global irradiance

La base de données HelioClim de rayonnement solaire disponible au sol : évolution majeure

Les première et deuxième générations de Météosat ont permis à MINES ParisTech de créer une base de données de rayonnement solaire mise à jour en temps réel de manière automatique. Les ressources HelioClim-1 (rayonnement solaire journalier de 1985 à fin 2005) et HelioClim-3 (périodes quart horaire, horaire, journalière et mensuelle depuis février 2004) sur l'Europe, l'Afrique, le Proche-Orient et l'Atlantique sont accessibles sur le site web SoDa http://www.soda-is.com. Une telle série temporelle de 1985 à aujourd'hui a fait d'HelioClim une ressource inestimable pour les acteurs du développement durable comme le montre la demande en forte augmentation et la nécessité de développer de nouvelles fonctionnalités pour accompagner leurs besoins. Ceci nous amène aujourd'hui à faire évoluer la base de données, d'une part en préparant la future ressource HelioClim-4, d'autre part en améliorant la résolution spatiale d'HelioClim-1 et -3 afin de proposer des applications à l'échelle locale

The performances of the HelioClim databases in Mozambique

International audienceThis paper deals with the solar irradiance observed at ground level on horizontal surfaces and integrated over the whole spectrum (total irradiance), also called surface solar irradiance (SSI). The HelioClim project is an initiative of MINES ParisTech / Armines launched in 1997, to increase knowledge on SSI and to offer SSI values for any site, any instant within a large geographical area and large period of time, to a wide audience. It covers Europe, Africa and the Atlantic Ocean. The HelioClim-1 database, abbreviated in HC-1, offers daily values of SSI for the period 1985-2005. It has been created from archives of images of the Meteosat First Generation (MFG). The HelioClim-3 database, abbreviated in HC-3, began in 2004 and is updtaed daily. It exploits the enhanced capabilities of the series of satellites Meteosat Second Generation (MSG) to deliver values of SSI every 15 min with a spatial resolution of 3 km at nadir. These databases are available on the SoDa Service (www.soda-is.com). Their performances have been already assessed by a comparison with SSI measurements made at a number of meteorological stations. However, most of these stations are located in Europe, a very few are available in Africa and very often for a limited period of time. This communication focuses on the specific case of Mozambique. Owing to the World Radiation Data Center, data from several stations are available though the period of measurements is often limited to a few years. We discuss the quality of the ground-based measured daily means of SSI. Then, we perform a comparison between these measurements and the HC values, using standard procedure and performance parameters. We quantify the quality of the SSI retrieved from HC-1 and HC-3. We conclude that the HelioClim databases are a good means to assess the SSI in Mozambique and that the close-to 30-years period covered by HelioClim helps in depicting the change in SSI

The operational calibration of images taken in the visible channel of the Meteosat-series of satellites

International audienceA method and its implementation are presented for the automatic calibration of the images taken in the visible channel of the Meteosat series of satellites. The method performs on a daily basis and is based on a statistical analysis of two images: one when the sun illuminates the entire field of view of Meteosat, the other during nighttime. This approach does not require any information about atmospheric and surface parameters, and therefore can be easily performed either on archived data, or in quasi-real time when receiving the images. Daily calibration coefficients were obtained since 1985 and are available on the Internet. The results are fully consistent with previous studies

The HelioClim Project: Surface Solar Irradiance Data for Climate Applications

URL : http://www.mdpi.com/2072-4292/3/2/343/International audienceMeteosat satellite images are processed to yield values of the incoming surface solar irradiance (SSI), one of the Essential Climate Variables. Two HelioClim databases, HC-1 and HC-3, were constructed covering Europe, Africa and the Atlantic Ocean, and contain daily and monthly means of SSI. The HC-1 database spans from 1985 to 2005; HC-3 began in 2004 and is updated daily. Their quality and limitations in retrieving monthly means of SSI have been studied by a comparison between eleven stations offering long time-series of measurements. A good agreement was observed for each site: bias was less than 10 W/m² in absolute value (5% in relative value) for HC-3. HC-1 offers a similar quality, though it underestimates the SSI for latitudes greater than 45° and less than −45°. Time-series running from 1985 to date can be created by concatenating the HC-1 and HC-3 values and could help in assessing SSI and its changes

Integrated DNA walking system to characterize a broad spectrum of GMOs in food/feed matrices

Background: In order to provide a system fully integrated with qPCR screening, usually used in GMO routine analysis, as well as being able to detect, characterize and identify a broad spectrum of GMOs in food/feed matrices, two bidirectional DNA walking methods targeting p35S or tNOS, the most common transgenic elements found in GM crops, were developed. These newly developed DNA walking methods are completing the previously implemented DNA walking method targeting the t35S pCAMBIA element. Results: First, the newly developed DNA walking methods, anchored on the sequences used for the p35S or tNOS qPCR screening, were tested on Bt rice that contains these two transgenic elements. Second, the methods were assessed on a maize sample containing a low amount of the GM MON863 event, representing a more complex matrix in terms of genome size and sensitivity. Finally, to illustrate its applicability in GMO routine analysis by enforcement laboratories, the entire workflow of the integrated strategy, including qPCR screening to detect the potential presence of GMOs and the subsequent DNA walking methods to characterize and identify the detected GMOs, was applied on a GeMMA Scheme Proficiency Test matrix. Via the characterization of the transgene flanking region between the transgenic cassette and the plant genome as well as of a part of the transgenic cassette, the presence of GMOs was properly confirmed or infirmed in all tested samples. Conclusion: Due to their simple procedure and their short time-frame to get results, the developed DNA walking methods proposed here can be easily implemented in GMO routine analysis by the enforcement laboratories. In providing crucial information about the transgene flanking regions and/or the transgenic cassettes, this DNA walking strategy is a key molecular tool to prove the presence of GMOs in any given food/feed matrix