Hybrid analysis of large scale PEPA models
نویسندگان
چکیده
We introduce a new hybrid analysis technique for large scale PEPA models that combines stochastic simulation with ODEs, providing a finer trade-off between accuracy of the solutions and the associated computational costs. We describe a version that employs ODEs for the mean component counts and also a version using ODEs for second order moments. This enables the calculation of covariances of component counts and also improves the accuracy of the mean approximations . We look at various examples demonstrating the advantages and limitations of this approach.
منابع مشابه
GPA – Tool for rapid analysis of very large scale PEPA models
We present a tool called Grouped PEPA Analyser (GPA) that allows fast analysis of large scale models described in the stochastic process algebra PEPA. GPA employs the techniques for approximations of transient moments in PEPA models with ordinary differential equations (ODEs), which allow analysis of systems with state spaces far beyond the limits of standard techniques. These moments provide u...
متن کاملAn aggregation technique for large-scale PEPA models with non-uniform populations
Performance analysis based on modelling consists of two major steps: model construction and model analysis. Formal modelling techniques significantly aid model construction but can exacerbate model analysis. In particular, here we consider the analysis of large-scale systems which consist of one or more entities replicated many times to form large populations. The replication of entities in suc...
متن کاملFundamental Results on Fluid Approximations of Stochastic Process Algebra Models
In order to avoid the state space explosion problem encountered in the quantitative analysis of large scale PEPA models, a fluid approximation approach has recently been proposed, which results in a set of ordinary differential equations (ODEs) to approximate the underlying continuous time Markov chain (CTMC). This paper presents a mapping semantics from PEPA to ODEs based on a numerical repres...
متن کاملAutomated Capacity Planning for PEPA Models
Capacity planning is concerned with the provisioning of systems in order to ensure that they meet the demand or performance requirements of users. Currently for PEPA models a modeller who wishes to solve a capacity planning problem has to either carry out a manual search for an optimal configuration or work outside the provided tool suite. We present a new extension to the Eclipse Plug-in for P...
متن کاملA Syntactical Analysis of Reversible PEPA Models
Product form solutions have played an important role in the development of performance modelling and in particular in the popularity of queueing network models. The notions of reversibility and quasi-reversibility underpin many product form results in queueing theory. Stochastic process algebras (SPAs) support a compositional approach to performance modelling without severe restriction on the f...
متن کامل