Rétrospective n° 19

La numérisation des catalogues : une analyse rétrospective

In the sector of the library all the professional activities reset on the creation and the management of the catalogues. The digitalization of those is an ambitious project whose complexity is difficult to evaluate and to manage. In this paper we are interested with in the problems arising at the practical implementation of such a project. We start by an introduction, then we define the bibliog...

Ja n 19 90 The Primal Framework

Ju n 19 94 Algorithms for Groups ∗

Group theory is a particularly fertile field for the design of practical algorithms. Algorithms have been developed across the various branches of the subject and they find wide application. Because of its relative maturity, computational group theory may be used to gain insight into the general structure of algebraic algorithms. This paper examines the basic ideas behind some of the more impor...

Ja n 19 99 Intermittency in turbulence

We derive from the Navier-Stokes equation an exact equation satisfied by the dissi-pation rate correlation function, < ǫ(x + r, t + τ)ǫ(x, t) >, which we study in the equal time limit. We exploit its mathematical similarity to the corresponding equation derived from the 1-dimensional stochastic Burgers equation to show that the main intermittency exponents are µ 1 = 2 − ζ 6 and µ 2 = 2 ˜ z 4 − ...

Ja n 19 99 Quantum slow motion

We simulate the center of mass motion of cold atoms in a standing, amplitude modulated, laser field as an example of a system that has a classical mixed phase-space. We show a simple model to explain the momentum distribution of the atoms taken after any distinct number of modulation cycles. The peaks corresponding to a classical resonance move towards smaller velocities in comparison to the ve...