Spatial Diffusion Processes 2: Numerical Analysis

An earlier paper (Webber and Joseph, 1978) proposed a model of the process whereby messages diffuse between a system of cities and provided a means of approximating the solution to that model if cities can ‘self-infect’ themselves with the message. This paper continues the analysis of this model by investigating the case in which a city cannot send the message to itself. The analysis is numerical, and an alternative to Monte Carlo simulation is used. The results indicate that the diffusion process described by the model is highly predictable if information on the accessibility of cities is available. A second part of the paper shows that the approximation used in the earlier paper provides a reasonable description of the model solution for at least some parameter values.