École normale supérieure de Cachan

About: École normale supérieure de Cachan is a education organization based out in Cachan, Île-de-France, France. It is known for research contribution in the topics: Decidability & Nonlinear system. The organization has 2717 authors who have published 5585 publications receiving 175925 citations.

Epistemic Logic for the Applied Pi Calculus

Abstract: We propose an epistemic logic for the applied pi calculus, which is a variant of the pi calculus with extensions for modeling cryptographic protocols. In such a calculus, the security guarantees are usually stated as equivalences . While process calculi provide a natural means to describe the protocols themselves, epistemic logics are often better suited for expressing certain security properties such as secrecy and anonymity. We intend to bridge the gap between these two approaches: using the set of traces generated by a process as models, we define a logic which has constructs for reasoning about both intruder's epistemic knowledge and the set of messages in possession of the intruder. As an example we consider two formalizations of privacy in electronic voting and study the relationship between them.

Joint A Contrario Ellipse and Line Detection

Abstract: We propose a line segment and elliptical arc detector that produces a reduced number of false detections on various types of images without any parameter tuning. For a given region of pixels in a grey-scale image, the detector decides whether a line segment or an elliptical arc is present ( model validation ). If both interpretations are possible for the same region, the detector chooses the one that best explains the data ( model selection ). We describe a statistical criterion based on the a contrario theory, which serves for both validation and model selection. The experimental results highlight the performance of the proposed approach compared to state-of-the-art detectors, when applied on synthetic and real images.

Practical Stabilization of a Quantum Particle in a One-Dimensional Infinite Square Potential Well

Abstract: We consider a nonrelativistic charged particle in a one-dimensional infinite square potential well. This quantum system is subjected to a control, which is a uniform (in space) time-depending electric field. It is represented by a complex probability amplitude solution of a Schrodinger equation on a one-dimensional bounded domain, with Dirichlet boundary conditions. We prove the almost global practical stabilization of the eigenstates by explicit feedback laws.

Quantitative Model-Checking of One-Clock Timed Automata under Probabilistic Semantics

Abstract: In a probabilistic semantics for timed automata has been defined in order to rule out unlikely (sequences of) events. The qualitative model-checking problem for LTL properties has been investigated, where the aim is to check whether a given LTL property holds with probability 1 in a timed automaton, and solved for the class of single-clock timed automata. In this paper, we consider the quantitative model-checking problem for omega-regular properties: we aim at computing the exact probability that a given timed automaton satisfies an omega-regular property. We develop a framework in which we can compute a closed-form expression for this probability; we furthermore give an approximation algorithm,and finally prove that we can decide the threshold problem in that framework.