Spatial Point Pattern Analysis of the Unidentified Aerial Phenomena in France

We model the unidentified aerial phenomena observed in France during the last 60 years as a spatial point pattern. We use some public information such as population density, rate of moisture or presence of airports to model the intensity of the unidentified aerial phenomena. Spatial exploratory data analysis is a first approach to appreciate the link between the intensity of the unidentified aerial phenomena and the covariates. We then fit an inhomogeneous spatial Poisson process model with covariates. We find that the significant variables are the population density, the presence of the factories with a nuclear risk and contaminated land, and the rate of moisture. The analysis of the residuals shows that some parts of France (the Belgian border, the tip of Britany, some parts in the SouthEast , the Picardie and Haute-Normandie regions, the Loiret and Corr eze departments) present a high value of local intensity which are not explained by our model

The skyrmion-bubble transition in a ferromagnetic thin film

Magnetic skyrmions and bubbles, observed in ferromagnetic thin films with perpendicular magnetic anisotropy, are topological solitons which differ by their characteristic size and the balance in the energies at the origin of their stabilisation. However, these two spin textures have the same topology and a continuous transformation between them is allowed. In the present work, we derive an analytical model to explore the skyrmion-bubble transition. We evidence a region in the parameter space where both topological soliton solutions coexist and close to which transformations between skyrmion and bubbles are observed as a function of the magnetic field. Above a critical point, at which the energy barrier separating both solutions vanishes, only one topological soliton solution remains, which size can be continuously tuned from micrometer to nanometer with applied magnetic field

Analyse aérodynamique et acoustique d'une architecture boxwing dans le cadre du projet PARSIFAL

International audienceThe present paper summarizes the main results obtained from the CFD analysis of a reference boxwing configuration designed during the initial phase of the PARSIFAL project, with focus on the assessment of its aerodynamic performance in the transonic regime. For such purpose, high-fidelity RANS computations have been carried out and a detailed inspection of the different drag sources, induced, wave and viscous drag components, is presented. In addition, preliminary results from the acoustic analysis of such innovative aircraft configuration are also discussed, concerning the impact of the engine location

Un cas de panostéite chez un Cairn Terrier

La panostéite est une affection osseuse idiopathique du chien en croissance touchant habituellement les races de grande taille. Elle atteint préférentiellement les os longs. Elle se manifeste cliniquement par une boiterie, une douleur à la palpation diaphysaire et radiologiquement par des plages d’ossification intramédullaire. L’observation chez un chiot Cairn Terrier est apparue particulièrement intéressante du fait de sa rareté

Extending Coq with Imperative Features and its Application to SAT Verification

This work was supported in part by the french ANR DECERT initiativeInternational audienceCoq has within its logic a programming language that can be used to replace many deduction steps into a single computation, this is the so-called reflection. In this paper, we present two extensions of the evaluation mechanism that preserve its correctness and make it possible to deal with cpu-intensive tasks such as proof checking of SAT traces

People Ex. Rel. Scott v. Briceland: Powers of the Attorney General Revisited, 11 J. Marshall J. Prac. & Proc. 441 (1978)

status: Published onlin

Automated deduction with associative commutative operators

We propose a new inference system for automated deduction with equality and associative commutative operators. This system is an extension of the ordered paramodulation strategy. However, rather than using associativity and commutativity as the other axioms, they are handled by the AC-unification algorithm and the inference rules. Moreover, we prove the refutational completeness of this system without needing the functional reflexive axioms or AC-axioms. Such a result is obtained by semantic tree techniques. We also show that the inference system is compatible with simplification rules

A Modular Integration of SAT/SMT Solvers to Coq through Proof Witnesses

International audienceWe present a way to enjoy the power of SAT and SMT provers in Coq without compromising soundness. This requires these provers to return not only a yes/no answer, but also a proof witness that can be independently rechecked. We present such a checker, written and fully certified in Coq. It is conceived in a modular way, in order to tame the proofs' complexity and to be extendable. It can currently check witnesses from the SAT solver ZChaff and from the SMT solver veriT. Experiments highlight the efficiency of this checker. On top of it, new reflexive Coq tactics have been built that can decide a subset of Coq's logic by calling external provers and carefully checking their answers

Stabilization of a premixed laminar flame on a rotating cylinder

This paper investigates the stabilization of a laminar premixed flame on a rotating cylinder. Experiments and DNS are combined to analyze the effects of rotation on the flow topology and flame stabilization. Both experiment and simulation reveal that the usual stabilization pattern (two symmetric flame roots on both sides of the cylinder) is strongly affected by rotation. The flame roots positions on the upper and lower sides of the cylinder are modified with increasing rotation speeds. One of the two flame roots is quenched over a long region. The distance of the flame roots to the flameholder changes with the rotation speed until a bifurcation takes place: at a critical rotation speed, the flame roots merge, and the flame stabilizes upstream of the cylinder. DNS results are used to explain the flame topologies observed experimentally

Compiling and Verifying Security Protocols

We propose a direct and fully automated translation from standard security protocol descriptions to rewrite rules. This compilation defines non-ambiguous operational semantics for protocols and intruder behavior: they are rewrite systems executed by applying a variant of ac-narrowing. The rewrite rules are processed by the theorem-prover DATAC. Multiple instances of a protocol can be run simultaneously as well as a model of the intruder (among several possible). The existence of flaws in the protocol is revealed by the derivation of an inconsistency. Our implementation of the compiler CASRUL, together with the prover DATAC, permitted us to derive security flaws in many classical cryptographic protocols