2008 NOV 24 - (VerticalNews.com) -- "In the context of communication networks, the framework of stochastic event graphs allows a modeling of control mechanisms induced by the communication protocol and an analysis of its performances. We concentrate on the logarithmic tail asymptotics of the stationary response time for a class of networks that admit a representation as (max,plus)-linear systems in a random medium," scientists writing in the journal Discrete Event Dynamic Systems - Theory and Applications report ...read more

  2008 NOV 24 - (VerticalNews.com) -- "In this paper, we show how to design a perfect sampling algorithm for stochastic Free-Choice Petri nets by backward coupling. For Markovian event graphs, the simulation time can be greatly reduced by using extremal initial states, namely blocking marking, although such nets do not exhibit any natural monotonicity property," scientists writing in the journal Discrete Event Dynamic Systems - Theory and Applications report ...read more

  2008 NOV 24 - (VerticalNews.com) -- "This paper considers a parallel system of queues fed by independent arrival streams, where the service rate of each queue depends on the number of customers in all of the queues," researchers in Netherlands report.

  "Necessary and sufficient conditions for the stability of the system are derived, based on stochastic monotonicity and marginal drift properties of multiclass birth and death processes. These conditions yield a sharp characterization of stability for systems where the service rate of each queue is decreasing in the number of customers in other queues, and has uniform limits as the queue lengths tend to infinity," wrote S. Borst and colleagues ...read more