Variations des dimensions des feullets en fonction de l’altitude

Annals of Telecommunications - As cours de la deuxième partie de cette série d’articles on a étudié un certain nombre de paramètres relatifs aux feuillets stables et...     

Mesure automatique des paramétres de bruit des MESFET hyperfréquences

An automatic noise parameter measurement test set is described in two sections : (i) A novel noise parameter extraction procedure from a set of noise figure measurements is developped. The experimental minimum noise figure is no longer required and the sensitivity to measurement incertainties is found to be very low. (ii) An automatic input tuner with a large number of precalibrated and reproducible positions is designed and realized. The last part give examples of broadband (8 to 17 GHz) noise parameters characterization ofmmic GaAsmesfets when both the automatic tuner and the extraction procedure are used.     

Calcul des métriques de routage pour Internet

In spite of the development of Internet networks and the important volume of literature dealing with Internet routing, many fundamental topics were not addressed. Traffic is, in principle, routed through shortest paths, in sense of a set of link weights (a metric). These weights do not necessarily have a physical significance and could be modified by the network administrator to change the routing policy and the network cost. In this paper, we give precise answers for the following questions: 1/ Given a network topology, is there a metric such that, first, the shortest path between any pair of vertices is unique and, second, every link belongs to at least one shortest path ? 2/ How can we compute such a metric ? 3/ Can we choose a metric satisfying these constraints and whose values are small integers ? 4/ If the routers of the network have differents functions and caracteristics, is it possibe to determine a metric which allows to route traffic, taking into account these heteregeneous caracteristics ? 5/ If some routing paths are seleceted due to technical or economical reasons, can we find a metric enforcing this given routing policy ? 6/ If this is not possible, what should we do to compute a metric that is as close as possible to the selected routing paths ?