TIPPtool: Compositional Specification and Analysis of Markovian Performance Models

In this short paper we briefly describe a tool which is based on a Markovian stochastic process algebra. The tool offers both model specification and quantitative model analysis in a compositional fashion, wrapped in a userfriendly graphical front-end

Stochastic Process Algebras - Between LOTOS and Markov Chains

This paper introduces stochastic process algebras as an approach for the structured design and analysis of both the functional behavior and performance characteristics of parallel and distributed systems. This is achieved by integrating stochastic modelling and analysis into process algebras like CCS or LOTOS. We demonstrate how notions of equivalent behavior -- substantial for process algebras -- stand in a new light for stochastic process algebras. In particular we discuss the impact of stochastic versions of such equivalences on compositional performance analysis by means of a running example. In addition we discuss analysis techniques, tool support and include a survey of related work as well as recent trends in this area. Keywords: Process Algebra, Performance Analysis, Stochastic Time, Markov Chains, Bisimulation. 1 Introduction -- Distributed Systems and their Formal Description One may safely assume that almost all substantial future computer- and information systems will be ..

Stochastic Process Algebras - Integrating Qualitative and Quantitative Modelling

In this paper we present an extension of the process algebra modelling methodology which allows qualitative and quantitative modelling to be integrated. This extension, to form stochastic process algebras (SPA), has been recently demonstrated to have many interesting features. Such languages serve two purposes as a formal description language for computer system models. Quantitative information may be used to predict the performance of the system whereas qualitative information may be exploited when reasoning about the functional behaviour of the system (e.g. when finding deadlocks or when exhibiting equivalences between subcomponents). While qualitative analysis is carried out using standard techniques for process algebras, quantitative analysis is based on an underlying continuous time Markov chain (CTMC). Several stochastic process algebras have recently appeared in the literature. Here we present the emerging concensus of the salient features for such languages and discuss their us..

Stochastic Process Algebras - Integrating Qualitative and Quantitative Modelling

ion mechanisms allow a subsystem to be modelled in detail but subsequently presented to its environment with only a restricted interface. Moreover the structure imposed on the model may also be used to control both functional and temporal analysis of the system. 2. The Approach In a SPA, as in a classical process algebra, a system is described as an interaction of agents. The behaviour of an agent is defined by the actions it can perform or as a composition of smaller agents. The ways such behaviours can be constructed are formally defined by a grammar which specifies how actions and agents may interact. Actions are atomic at the chosen level of abstraction. Each of the published SPA [1, 2, 5, 8, 9] has settled on the same core set of combinators: prefix, choice, concurrency and hiding. Hiding provides the abstraction mechanism within the language. In classical process algebras only the relative ordering of events is modelled and branching is non-deterministic. Recent timed and prob..

Stochastic Process Algebras - Constructive Specification Techniques Integrating Functional, Performance and Dependability Aspects

This paper is organised as follows: in Section 2 we will give an overview on how everything began. We will introduce TIPP as an example of a Stochastic Process Algebra in Section 3, where we especially highlight the nice and important algebraic features of the approach. Section 4 illuminates the concept by means of a small example. Section 5 gives references to various case studies and Section 6 discusses tool support that is actually available