Conservatoire national des arts et métiers

About: Conservatoire national des arts et métiers is a education organization based out in Paris, France. It is known for research contribution in the topics: Population & Orthogonal frequency-division multiplexing. The organization has 3573 authors who have published 7127 publications receiving 141430 citations. The organization is also known as: CNAM & Conservatoire des arts et métiers.

New efficient petri nets reductions for parallel programs verification

Abstract: Structural model abstraction is a powerful technique for reducing the complexity of a state based enumeration analysis. We present in this paper new efficient Petri nets reductions. First, we define "behavioural" reductions (i.e. based on conditions related to the language of the net) which preserve a fundamental property of a net (i.e. liveness) and any formula of the (action-based) linear time logic that does not observe reduced transitions of the net. We show how to replace these conditions by structural or algebraical ones leading to reductions that can be efficiently checked and applied whereas enlarging the application spectrum of the previous reductions. At last, we illustrate our method on a significant and typical example of a synchronisation pattern of parallel programs.

Internet and the “Long Tail vs. Superstar effect” debate: Evidence from the French Book Market

Abstract: From a comprehensive database of monthly sales of comic books and literature books in France over the period 2003 to 2007, we show that (i) bestsellers got smaller market shares online than offline, contrary to medium- and low-sellers; (ii) both online and offline sales shift from the head of the distribution to the tail with increasing magnitude over the period; and (iii) the Long Tail appears to be more than just a short-lived phenomenon caused by the specific preferences of early adopters of e-commerce. These three results suggest that online information and distribution tools, whose use increased over the period 2003 to 2007, do have an impact on book distribution and on consumers’ purchase decisions.

Energy-based Lyapunov functions for forced Hamiltonian systems with dissipation

Abstract: We propose a constructive procedure to modify the total energy function of forced Hamiltonian systems with dissipation in order to generate Lyapunov functions for non-zero equilibria. A key step in the procedure, which is motivated from energy-balance considerations standard in network modeling of physical systems, is to embed the system into a larger Hamiltonian system for which a series of Casimir functions (i.e., first integrals) can be easily constructed. For linear systems the resulting Lyapunov function is the incremental energy, thus our derivations provide a physical explanation to it. An easily verifiable necessary and sufficient condition for the applicability of the technique in the general nonlinear case is given. Some examples that illustrate the method are given.