Scientific Publications of the University of Toulouse II Le Mirail
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Combe-Cullier (Lacave, Lot) : une séquence exceptionnelle du Magdalénien au bord de la Dordogne lotoise
No full textInternational audienceThe Combe-Cullier site (Lacave, Lot) is one of the few sites with a Magdalenian archaeosequence investigated using modern excavation methods. Its exceptional archaeological fill covers the entire Magdalenian period between 21,000 and 14,000 cal. BP. The cave was excavated in the early 20th century under the aegis of A. Viré, yielding remains of occupations for which no contextual data are available. Then, at the end of the 1960s, J.-F. Flies began a new operation on the slope in front of the cave, and carried out meticulous excavations using modern methodology until the mid-1970s. Most of the artefacts unearthed in the nearly five-metre-thick stratigraphic sequence are still unpublished to this day. Following academic work on elements of this collection, a multidisciplinary team was formed to re-examine all the remains in a revised chronostratigraphic framework. The results of this work are presented here by archaeostratigraphic unit (AU) and according to the different analysed artefacts (siliceous materials, bone industry, adornments, fauna). It is thus possible to track evolution at the site over nearly 7,000 years, highlighting continuities and changes. A comparison of the results obtained at Combe-Cullier with other sites in south-western France backs up the recent proposal for a new evolutionary scenario for the Aquitaine Magdalenian.Parmi les rares gisements fournissant des archéo-séquences du Magdalénien contrôlées par des méthodes de fouilles modernes, le site de Combe-Cullier (Lacave, Lot) fait office d’exception. La dilatation de son remplissage archéologique couvre, en effet, toute l’évolution du Magdalénien entre 21000 et 14000 cal. BP. Fouillée dès le début du xxe siècle sous l’égide d’A. Viré, cette grotte a livré des vestiges d’occupations dont les données contextuelles sont inaccessibles. Aussi, à la fin des années 1960, quand J.-F. Flies démarre une nouvelle opération dans le talus situé au-devant de la grotte, l’occasion lui est donnée de réaliser des fouilles suivant une méthodologie moderne, et un travail minutieux s’engage alors jusqu’au milieu des années 1970. L’essentiel du mobilier mis au jour au sein d’une séquence puissante de près de cinq mètres reste inédit à ce jour. À la suite de travaux universitaires mobilisant des éléments de cette collection, une équipe pluridisciplinaire s’est réunie afin de réexaminer l’ensemble des vestiges dans d’un cadre chronostratigraphique renouvelé. Les résultats de ce travail sont présentés ici par unité archéostratigraphique (UA) et suivant les registres analysés (silicites, industrie osseuse, éléments de parure, faune). Ils permettent de documenter leur évolution sur près de 7000 ans, soulignant des continuités et des changements. La comparaison des résultats obtenus à Combe-Cullier avec d’autres sites du sud-ouest de la France permet de consolider la proposition récente d’un nouveau scénario évolutif du Magdalénien aquitain
On the use of optomechanical devices as chaos-generating systems for chaotic cryptography
No full textInternational audienceIn recent years, chaotic systems have received increasing attention for their potential applications in sensing and the possibility of implementing secure communication thanks to chaos-based cryptography. Chaotic cryptography is a type of material cryptography in which the information to be transferred is masked with a larger amplitude signal generated by a chaotic system. On the receiver side, the mixed signal is fed to a similar chaotic system which synchronizes to the first one resulting in a retrieval of the information. The chaotic systems in the transmitting and receiving sides must have dynamics similar enough to achieve synchronisation and thus a specific material system is needed.MEMS devices and chaotic lasers have been proposed as chaotic systems for implementing this material cryptography. MEMS have the advantage of being efficient, compact and easily integrated devices whereas lasers are compatible with standard optical communication infrastructures. Current fiber links offer low loss and very large bandwidth, allowing high speed transfer of signals across long distances. Experimental demonstrations using modulated chaotic lasers for encrypted communication have been performed [1]. The use of optomechanical devices would bridge the gap between both technologies, offering at the same time the large bandwidth and compatibility with telecom infrastructure while being efficient and compact. In this work we study the feasibility of using optomechanical systems for implementing chaotic-based encryption. These fundamentally non-linear systems are known to enter chaotic regimes in low-frequencies (tens of KHz) due to thermo-optic slow dynamic effects [2] as well as due to the intrinsically non-linear optomechanical coupling for frequencies as high as that of the mechanical mode at GHz range. For certain excitation parameters, the system is also prone to dynamical onset of chaos by frequency and amplitude modulation of the driving signal [3]. The different chaotic regimes that might be achievable using a single optomechanical cavity, direct transduction of the chaotic signal into laser frequency for optical fiber transmission, and the high degree of integration of fully silicon based optomechanical cavities achievable makes them a solution worth exploring for chaotic based cryptography
On the convergence of global-optimization fraudulent stochastic algorithms
No full textInternational audienceWe introduce and analyse the almost sure convergence of a new stochastic algorithm for the global minimization of Morse functions on compact Riemannian manifolds. This diffusion process is called fraudulent because it requires the knowledge of minimal value of the function. Its investigation is nevertheless important, since in particular it appears as the limit behavior of non-fraudulent and time-inhomogeneous swarm mean-field algorithms used in global optimization
A model for framed configuration spaces of points
No full text47 pages, revised and expanded version. Comments are welcomeWe study configuration spaces of framed points on compact manifolds. Such configuration spaces admit natural actions of the framed little discs operads, that play an important role in the study of embedding spaces of manifolds and in factorization homology. We construct real combinatorial models for these operadic modules, for compact smooth manifolds without boundary
Optimization-Aided Construction of Multivariate Chebyshev Polynomials
No full textInternational audienceThis article is concerned with an extension of univariate Chebyshev polynomials of the first kind to the multivariate setting, where one chases best approximants to specific monomials by polynomials of lower degree relative to the uniform norm. Exploiting the Moment-SOS hierarchy, we devise a versatile semidefinite-programming-based procedure to compute such best approximants, as well as associated signatures. Applying this procedure in three variables leads to the values of best approximation errors for all mononials up to degree six on the euclidean ball, the simplex, and the cross-polytope. Furthermore, inspired by numerical experiments, we obtain explicit expressions for Chebyshev polynomials in two cases unresolved before, namely for the monomial on the euclidean ball and for the monomial on the simplex
« Hacia el Mundo Zurdo: performatividad, supervivencia y futuros cuir/crip »
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"The New Conditions of Post-classical Entertainment: Duplication, Repetition and the Loss of Authenticity in Cronenberg’s Maps to the Stars"
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Efficient Evaluation of 2-D Collision Probability Derivatives for Uncertain k-scaled Covariances: A PcMax Case Study
No full textInternational audienceThis paper focuses on efficiently evaluating derivatives of the 2-D collision probability, treated as a function of parameters, which appear as linear forms in the entries of the covariance matrix. This boils down to computing moments of the associated Gaussian measure restricted to a disk. Specifically, we propose an optimization-based solution to computing the maximum collision probability when the covariance data is unreliable, implementing an alternative method to the traditional k-scaled covariance approach. Preliminary results indicate our method's potential for improving the understanding of Pc's validity as a measure of conjunction likelihood
Contre-pédagogies de la cruauté
No full textRita Laura Segato, Contra pedagogías de la crueldad, 2018Cet ouvrage est une compilation de trois conférences dispensées à l'Université de Rosario, Argentine, par Rita Laura Segato en 2016 et publié chez Prometeo en 2018. Il présente la notion phare de "contre-pédagogie de la cruauté" dans un exercice académique peu conventionnel de co-écriture et de réflexion épistémologique et autobiographique d'un parcours de vie dédié à la lutte contre la violence coloniale
Caledonian elected representatives' perception of family farming and fishing
No full textInternational audienceHow do New Caledonia's elected representatives perceive family farming and fishing? How do they see them in relation to the country's other productive activities? What do they see as the main issues, strengths and weaknesses, and how are they developing? To answer these questions, which are central to the FALAH project, in March 2022 we conducted individual qualitative interviews in face-to-face with seventeen elected representatives from the Territory (mayors, representatives at Congress, at the CESE, etc.), in both urban and rural areas, which main results will be presented