Comparinganindividual-basedmodel.docVIP

 HYPERLINK http://jasss.soc.surrey.ac.uk/6/4/9/Edwards.html Margaret Edwards, Sylvie Huet, Fran?ois Goreaud and Guillaume Deffuant (2003) Comparing an individual-based model of behaviour diffusion with its mean field aggregate approximation Journal of Artificial Societies and Social Simulation vol. 6, no. 4http://jasss.soc.surrey.ac.uk/6/4/9.html To cite articles published in the Journal of Artificial Societies and Social Simulation, please reference the above information and include paragraph numbers if necessary Received: 13-Jul-2003 ?????Accepted: 13-Jul-2003 ?????Published: 31-Oct-2003 Abstract In this paper we compare a version of the individual-based threshold model of innovation diffusion with an aggregate deterministic model that we constructed from it. The classical threshold model supposes that an individual adopts a behaviour according to a trade-off between a social pressure (the number of neighbours adopting the behaviour) and a personal interest or resistance to change (the threshold). The aggregate model makes approximations in order to estimate the evolution of groups of individuals with the same number of neighbours of similar behaviour. We compare both models at different points of the parameter space. We find that the aggregate model gives a good approximation of the individual in some cases; however in other cases the behaviour of the aggregate approximation differs. Using theoretical interpretation of this difference based on a study of the attractors of the aggregate model, we hypothesise that the two models have the same behaviour when the aggregate model has only one attractor and that differences can occur when it has two. Keywords: Aggregate; Individual-based; Innovation Diffusion; Mean Field Approximation; Model Comparison Introduction 1.1 （个体层面模型） Individual-based models (also referred to as IBM) are more and more commonly used in ecological modelling ( HYPERLINK http://jasss.soc.surrey.ac.uk/6/4/9.html \l grimm1999#grimm19