Framework Of Perturbation Analysis Research Articles

Full-state perturbation analysis of discrete event dynamic systems

Discrete event dynamic systems are studied within the framework of perturbation analysis in this paper. Perturbation is extended from the event times only to both event times and queue lengths. An approximate technique, full-state perturbation analysis (PA), is developed as an extension of the PA approach. Full-state PA is able to deal with problems involving queue length perturbations which often defy existing PA methods, while it still retains all the advantages of existing PA. Full-state PA is used to calculate the throughput sensitivity to the number of customers in closed queueing networks and the throughput sensitivity to routing change. Numerical examples are given. Experimental results verify the validity and accuracy.

The Horizontal Diffusion of Tracers by Surface Waves

Abstract The horizontal dispersion of tracers in the presence of a random field of ocean surface waves is examined. Random fluctuations in the local Stokes-drift current cause a water particle to follow a random-walk path. The associated diffusion coefficients for individual particles, particle pairs and a continuous tracer patch can be calculated rigorously within the framework of perturbation analysis. For a fully developed Pierson-Moskowitz wave spectrum all diffusion coefficients scale as the third power of the wind speed and are typically of the order 10−2 m2 s−1 for a wind speed of 10 m s−1. The diffusion coefficients are strongly anisotropic and decrease approximately exponentially with depth below the sea surface.