Modeling and Calibration of Coupled Fish-Eye CCD Camera and Laser Range Scanner for Outdoor Environment Reconstruction

International audiencePrecise and realistic models of outdoor environments such as cities and roads are useful for various applications. In order to do so, geometry and photography of environments must be captured. We present in this paper a coupled system , based on a fish-eye lens CCD camera and a laser range scanner, aimed at capturing color and geometry in this context. To use this system, a revelant model and a accurate calibration method are presented. The calibration method uses a simplified fish-eye model; the method uses only one image for fish-eye parameters, and avoids the use of large calibration pattern as required in others methods. The validity and precision of the method are assessed and example of colored 3D points produced by the system is presented

LA QUALITE, LA QUALIFICATION ET L'ACTION COLLECTIVE DANS LES PROCESSUS D'INNOVATION ET D'ACTIVATION DES SYAL LE CAS DES FROMAGERIES RURALES EN AMERIQUE LATINE

N° ISBN - 978-2-7380-1284-5International audienceSince the late nineties in Latin America, a new way of Rural Agro-Industry (RAI) development has been opened with Localized Agri-food Systems (SYAL in French). It appeared from existing relationships between geographical concentrations of RAI and the territory and with the idea of coping with new challenges brought about by globalization. This perspective is particularly relevant in the dairy and cheese dairy sectors. The main objective of this paper is to present an analysis of cheese dairy Localized Agri-food Systems activation, based on various case studies in Latin America that were presented during a workshop held in Toluca, Mexico, in November 2009. We highlight the necessary conditions to land resources activation in the strategies of local development based on the relationship between the territory and food products. In particular, we try to show that the various forms of the articulation between territory and value chain on the one hand, and the constitution of external or internal social networks on the other hand, largely determine the modality of collective actions and their results. In the specific case of milk that we are dealing with, it appears that the basis of local development process rests on the co-construction of a territorialized resource connected with quality and know-haw, such as collective trademarks, registered designation of origin and geographical indication of origin

SYAL : UN NOUVEL OUTIL POUR LE DEVELOPPEMENT DE TERRITOIRES MARGINAUX. LES LEÇONS DE L'ALLIANCE DES AGRO-INDUSTRIES RURALES DE LA SELVA LACANDONA, CHIAPAS.

N° ISBN - 978-2-7380-1284-5International audienceSince its beginnings in the eighties, Rural Agro-Industry (RAI) has emerged as an effective way to fight against poverty in marginalized rural areas, because of its ability to contribute to the overall improvement of small producers' living conditions. This development tool has been completed in the nineties by the Localized Agri-food Systems concept (SYAL in French) and the process of their activation. From the experience of a RAI development project promoted in the Selva Lacandona (Chiapas, Mexico), we present some lessons learned from this development project. One of the principal results was to identify and define the conditions of RAI sustainability in the Selva Lacandona. If economics profitability of the micro-enterprises proved to be essential to ensure their viability, it does not seem central as it doesn't represent a real problem. On the other hand, two aspects appeared to be fundamental to guarantee the RAI sustainable development in such marginalized region: the necessity of a prior favorable environment, in particular trough the presence of functional local public goods, and the resolution of organization and leadership problems

The Cosmic Ray Lepton Puzzle

Recent measurements of cosmic ray electrons and positrons by PAMELA, ATIC, Fermi and HESS have revealed interesting excesses and features in the GeV-TeV range. Many possible explanations have been suggested, invoking one or more nearby primary sources such as pulsars and supernova remnants, or dark matter. Based on the output of the TANGO in PARIS --Testing Astroparticle with the New GeV/TeV Observations in Positrons And electRons : Identifying the Sources-- workshop held in Paris in May 2009, we review here the latest experimental results and we discuss some virtues and drawbacks of the many theoretical interpretations proposed so far.Comment: 6 pages, 3 figures, Extended version of the proceeding of the annual meeting of the French Astronomical & Astrophysical Society (sf2a

La Mécanisation de l’Armurerie Militaire (1855-1869)

In the nineteenth century, the manufacture of military small arms (rifles and pistols) cannot stay out of the progress of the Industrial Revolution. It is therefore, quite logically, to be a process of mechanization, which is also a human adventure. In fact, from 1850 to 1870, is almost the Second Empire, which actually marks the entry of France into the modern era, the military and political leaders face a double challenge: to equip the army of a modern rifle, as we were in a period of intense technological innovation, and move from a largely manual production, provided by qualified gunsmiths, a mechanized production, in which the systematic use of machine tools enable real interchangeability of parts. This is the mark of a modern industrial manufacturing

Local Government Taxation in Sub-Saharan Africa

This paper reviews the state of knowledge on local government revenue systems in Africa, with a particular focus on commonalties and differences between Francophone and Anglophone countries in Sub-Saharan Africa. The analysis addresses the composition of local government ‘own’ revenues, administrative practices, and how the current revenue system affects economic efficiency and accountability. Based on findings from the review and knowledge gaps identified, areas for further research on local government revenue mobilisation are suggested. Combining research on the technical and administrative framework for local taxation with the political and economic realities at the local and central levels has the potential to identify constraints and practices that can guide policy work and be used as benchmarks to assess actual policy implementation.Department for International DevelopmentBill and Melinda Gates Foundatio

Finite element modeling of dynamic frictional rupture with rate and state friction

Numerous laboratory experiments have demonstrated the dependence of the friction coefficient on the interfacial slip rate and the contact history, a behavior generically called rate and state friction. Although numerical models have been widely used for analyzing rate and state friction, in general they consider infinite elastic domains surrounding the sliding interface and rely on boundary integral formulations. Much less work has been dedicated to modeling finite size systems to account for interactions with boundaries. This paper investigates rate and state frictional interfaces in the context of finite size systems with the finite element method in explicit dynamics. We investigate the long term behavior of the sliding interface for two different friction laws: a velocity weakening law, for which the friction monotonously decreases with increasing sliding velocity, and a velocity weakening-strengthening law, for which the friction coefficient first decreases but then increases above a critical velocity. We show that for both friction laws at finite times, that is before wave reflections from the boundaries come back to the sliding interface, a temporary steady state sliding is reached, with a well-defined stress drop at the interface. This stress drop gives rise to a stress concentration and leads to an analogy between friction and fracture. However, at longer times, that is after multiple wave reflections, the stress drop is essentially zero, resulting in losing the analogy with fracture mechanics. Finally, the simulations reveal that velocity weakening is unstable at long time scales, as it results in an acceleration of the sliding blocks. On the other hand, velocity weakening-strengthening reaches a steady state sliding configuration

MODELISATION 3D DE ROUTES PAR TELEMETRIE LASER EMBARQUEE POUR LA MESURE DE DISTANCE DE VISIBILITE

National audienceLa plateforme LARA-3D, développée au Centre de Robotique de Mines Paris, est un système de télémétrie laser embarquée sur véhicule permettant de numériser des environnements routiers ou urbains à la vitesse du déplacement, et d'obtenir ainsi des nuages de points 3D denses. Nous présentons l'utilisation de ce système à des fins de mesure de distances de visibilité sur des routes, effectuée dans le cadre du projet SARI/VIZIR, en partenariat avec le LRPC de Strasbourg

Chemical Evolution of Damped Ly alpha galaxies: The [S/Zn] abundance ratio at redshift z > 2

Relative elemental abundances, and in particular the alpha/Fe ratio, are an important diagnostic tool of the chemical evolution of damped Ly alpha systems (DLAs). The S/Zn ratio is not affected by differential dust depletion and is an excellent estimator of the alpha/Fe ratio. We report 6 new determinations of sulphur abundance in DLAs at zabs greater than or equal to 2 with already known zinc abundances. The combination with extant data from the literature provides a measure of the S/Zn abundance ratio for a total of 11 high redshift DLA systems. The observed [S/Zn] ratios do not show the characteristic [alpha/Fe] enhancement observed in metal-poor stars of the Milky Way at comparable level of metallicity ([Zn/H] ~ -1). The behaviour of DLAs data is consistent with a general trend of decreasing [S/Zn] ratio with increasing metallicity [Zn/H]. This would be the first evidence of the expected decrease of the alpha/Fe ratio in the course of chemical evolution of DLA systems. However, in contrast to what observed in our Galaxy, the alpha/iron-peak ratio seems to attain solar values when the metallicity is still low ([Zn/H] < -1) and to decrease below solar values at higher metallicities. The behaviour of the alpha/Fe ratio challenges the frequently adopted hypothesis that high redshift DLAs are progenitors of spiral galaxies and favours instead an origin in galaxies characterized by low star formation rates, in agreement with the results from imaging studies of low redshift DLAs, where the candidate DLA galaxies show a variety of morphological types including dwarfs and LSBs and only a minority of spirals.Comment: ApJ (accepted

Horizontally-aligned carbon nanotubes arrays and their interactions with liquid crystal molecules: Physical characteristics and display applications

We report on the physical characteristics of horizonthally-grown Single-Walled Carbon Nanotubes (h-al-SWNT) arrays and their potential use as transparent and conducting alignment layer for liquid crystals display devices. Microscopy (SEM and AFM), spectroscopic (Raman) and electrical investigations demonstrate the strong anisotropy of h-al-SWNT arrays. Optical measurements show that h-al-SWNTs are efficient alignment layers for Liquid Crystal (LC) molecules allowing the fabrication of optical wave plates. Interactions between h-al-SWNT arrays and LC molecules are also investigated evidencing the weak azimuthal anchoring energy at the interface, which, in turn, leads to LC devices with a high pretilt angle. The electro-optical reponses of h-al-SWNT/LC cells demonstrate that h-al-SWNT arrays are efficient nanostructured electrodes with potential use for the combined replacement of Indium Tin Oxyde and polymeric alignment layers in conventional displays