Ultra-high-frequency piecewise-linear chaos using delayed feedback loops

We report on an ultra-high-frequency (> 1 GHz), piecewise-linear chaotic system designed from low-cost, commercially available electronic components. The system is composed of two electronic time-delayed feedback loops: A primary analog loop with a variable gain that produces multi-mode oscillations centered around 2 GHz and a secondary loop that switches the variable gain between two different values by means of a digital-like signal. We demonstrate experimentally and numerically that such an approach allows for the simultaneous generation of analog and digital chaos, where the digital chaos can be used to partition the system's attractor, forming the foundation for a symbolic dynamics with potential applications in noise-resilient communications and radar

Playing With Population Protocols

Population protocols have been introduced as a model of sensor networks consisting of very limited mobile agents with no control over their own movement: A collection of anonymous agents, modeled by finite automata, interact in pairs according to some rules. Predicates on the initial configurations that can be computed by such protocols have been characterized under several hypotheses. We discuss here whether and when the rules of interactions between agents can be seen as a game from game theory. We do so by discussing several basic protocols

Limit order market analysis and modelling: on an universal cause for over-diffusive prices

We briefly review data analysis of the Island order book, part of NASDAQ, which suggests a framework to which all limit order markets should comply. Using a simple exclusion particle model, we argue that short-time price over-diffusion in limit order markets is due to the non-equilibrium of order placement, cancellation and execution rates, which is an inherent feature of real limit order markets.Comment: 6 pages, 3 figures. Contribution to the proceedings of Econophysics Bali Conference 200

A refinement-based approach to large scale reflection for algebra

National audienceLarge scale reflection tactics are often implemented with ad-hoc data-structures and in a way which is specific to the problematic. This makes it hard to add improvements and to implement variations without writing an extensive theory of the specific data-structures involved. We suggest to replace the core of such tactics with procedures that are proven correct using CoqEAL refinement framework, and to build a modular methodology around it. This refinement framework addresses the problem of duplication by promoting the use of one extensive proof-oriented library together with one or several more efficient implementations, with a reduced amount of proofs, but destined to computation and proven correct with regard to the proof-oriented library. We show on the example of the ring tactic of Coq that this gain in flexibility opens the door to different improvements. This is a presentation to trigger discussion about ideas for a prototype based on the existing but improved CoqEAL refinement framework, described in [5] and [3]

Pour une anthropologie des matérialités religieuses

Poser la question de la relation entre religieux et matérialités peut paraître à la fois évident et dissonant. Évident, car la matérialité est une dimension nécessaire de l’expérience humaine. Dissonant, car ces termes ont longtemps été tenus à distance. Cet antagonisme classique persiste sous diverses formes, au même titre que technique et rituel, savoir et croyance, corps et esprit, rendant problématique une compréhension des phénomènes religieux qui tenterait de concilier l’analyse des app..

Bien ou mal payés ?:Les travailleurs du public et du privé jugent leurs salaires

Le salaire est une composante essentielle du niveau de vie. Son montant présente pour l’immense majorité des travailleurs un enjeu considérable. Comment les différents salariés perçoivent-ils à la fois le salaire qu’ils touchent et les écarts qui le séparent de celui des autres ? Portant sur les modalités subjectives de la perception des salaires ainsi que sur les critères de justice auxquels se réfèrent les individus pour évaluer leur montant, les deux grandes enquêtes dont est issu cet ouvrage mettent au jour les relations que les travailleurs entretiennent avec leur salaire ainsi que le sens qu’ils attribuent à leur rémunération. Un même questionnaire, l’enquête « SalSa » (« les salaires vus par les salariés »), a été administré à un échantillon de salariés des entreprises, privées et publiques, d’un côté, et à un échantillon de salariés de la fonction publique de l’autre. Il ressort de ces enquêtes que, du point de vue des salariés, le salaire ne se réduit jamais à une simple somme d’argent destinée à satisfaire des besoins. C’est aussi une façon de mesurer la valeur du travail accompli, sa reconnaissance par la société et donc la valeur de la personne elle-même, en soi mais aussi en relation avec les autres. C’est pourquoi la façon dont les individus connaissent, appréhendent et jugent leur rémunération et celle des autres est un élément essentiel pour comprendre les procédures de détermination et donc de négociation des salaires, mais aussi le sens que les individus attribuent à leur travail. (Résumé éditeur

Developing a Relationship Between LIBS Spectra and Pit Volume for in Situ Dating of Geologic Samples

No abstract availabl

Formalization Techniques for Asymptotic Reasoning in Classical Analysis

International audienceFormalizing analysis on a computer involves a lot of “epsilon-delta” reasoning, while informal reasoning may use some asymptotical hand-waving. Whether or not the arithmetic details are hidden using some abstraction like filters, a human user eventually has to break it down for the proof assistant anyway, and provide a witness for the existential variable “delta”. We describe formalization techniques that take advantage of existential variables to delay the input of witnesses until a stage where the proof assistant can actually infer them. We use these techniques to prove theorems about classical analysis and to provide equational Bachmann-Landau notations. This partially restores the simplicity of informal hand-waving without compromising the proof. As expected this also reduces the size of proof scripts and the time to write them, and it also makes proofs more stable

Volumetric Measurement of Ultra-Long Ablation of Geologic Samples Under High Vacuum for In Situ Dating of Planetary Samples

No abstract availabl

Relationship Between LIBS Ablation and Pit Volume for Geologic Samples: Applications for the In Situ Absolute Geochronology

These first results demonstrate that LIBS spectra can be an interesting tool to estimate the ablated volume. When the ablated volume is bigger than 9.10(exp 6) cubic micrometers, this method has less than 10% of uncertainties. Far enough to be directly implemented in the KArLE experiment protocol. Nevertheless, depending on the samples and their mean grain size, the difficulty to have homogeneous spectra will increase with the ablated volume. Several K-Ar dating studies based on this approach will be implemented. After that, the results will be shown and discussed