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54
The PEPA Workbench: A Tool to Support a Process Algebrabased Approach to Performance Modelling
 In Proceedings of the Seventh International Conference on Modelling Techniques and Tools for Computer Performance Evaluation, number 794 in Lecture Notes in Computer Science
, 1994
"... . In this paper we present a new technique for performance modelling and a tool supporting this approach. Performance Evaluation Process Algebra (PEPA) [1] is an algebraic language which can beused to build models of computer systems which capture information about the performance of the system. The ..."
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Cited by 176 (62 self)
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. In this paper we present a new technique for performance modelling and a tool supporting this approach. Performance Evaluation Process Algebra (PEPA) [1] is an algebraic language which can beused to build models of computer systems which capture information about the performance of the system. The PEPA language serves two purposes as a formal description language for computer system models. The performancerelated information in the model may be used to predict the performance of the system whereas the behavioural information in the model may be exploited when reasoning about the functional behaviour of the system (e.g. when finding deadlocks or when exhibiting equivalences between subcomponents). In this paper we concentrate on the performance aspects of the language. A method of reasoningaboutPEPA modelsproceedsby considering the derivation graph obtained from the model using the underlying operational semantics of the PEPA language. The derivation graph is systematically reduced ...
Multiprocessor and Distributed System Design: The Integration of Functional Specification and Performance Analysis Using Stochastic Process Algebras
, 1993
"... We introduce Stochastic Process Algebras as a novel approach for the structured design and analysis of both the functional behaviour and performance characteristics of parallel and distributed systems. This is achieved by integrating performance modelling and analysis into the powerful and well i ..."
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Cited by 138 (17 self)
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We introduce Stochastic Process Algebras as a novel approach for the structured design and analysis of both the functional behaviour and performance characteristics of parallel and distributed systems. This is achieved by integrating performance modelling and analysis into the powerful and well investigated formal description technique of process algebras. After advocating the use of stochastic process algebras as a modelling technique we recapitulate the foundations of classical process algebras. Then we present extensions of process algebras such that the requirements of performance analysis are taken into account. Examples illustrate the methodological advantages that are gained.
A tutorial on EMPA: A theory of concurrent processes with nondeterminism, priorities, probabilities and time
 Theoretical Computer Science
, 1998
"... In this tutorial we give an overview of the process algebra EMPA, a calculus devised in order to model and analyze features of realworld concurrent systems such as nondeterminism, priorities, probabilities and time, with a particular emphasis on performance evaluation. The purpose of this tutorial ..."
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Cited by 117 (11 self)
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In this tutorial we give an overview of the process algebra EMPA, a calculus devised in order to model and analyze features of realworld concurrent systems such as nondeterminism, priorities, probabilities and time, with a particular emphasis on performance evaluation. The purpose of this tutorial is to explain the design choices behind the development of EMPA and how the four features above interact, and to show that a reasonable trade off between the expressive power of the calculus and the complexity of its underlying theory has been achieved.
Process Algebra for Performance Evaluation
, 2000
"... This paper surveys the theoretical developments in the field of stochastic process algebras, process algebras where action occurrences may be subject to a delay that is determined by a random variable. A huge class of resourcesharing systems  like largescale computers, clientserver architectur ..."
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Cited by 72 (13 self)
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This paper surveys the theoretical developments in the field of stochastic process algebras, process algebras where action occurrences may be subject to a delay that is determined by a random variable. A huge class of resourcesharing systems  like largescale computers, clientserver architectures, networks  can accurately be described using such stochastic specification formalisms.
Compositional Performance Modelling with the TIPPtool
 PERFORMANCE EVALUATION
, 1998
"... Stochastic Process Algebras have been proposed as compositional specification formalisms for performance models. In this paper, we describe a tool which aims at realising all beneficial aspects of compositional performance modelling, the TIPPtool. It incorporates methods for compositional specificat ..."
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Cited by 53 (19 self)
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Stochastic Process Algebras have been proposed as compositional specification formalisms for performance models. In this paper, we describe a tool which aims at realising all beneficial aspects of compositional performance modelling, the TIPPtool. It incorporates methods for compositional specification as well as solution, based on stateofthearttechniques, and wrapped in a userfriendly graphical front end. Apart from highlighting the general benefits of the tool, we also discuss some lessons learned during development and application of the TIPPtool. A nontrivial model of a real life communication system serves as a case study to illustrate benefits and limitations.
Theory and Application of Extended Markovian Process Algebra
, 1999
"... Many computing systems consist of a possibly huge number of components that not only work independently but also communicate with each other. The catastrophic consequences of failures, such as loss of human lives, environmental damages, and financial losses, in many of these critical systems compel ..."
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Cited by 49 (15 self)
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Many computing systems consist of a possibly huge number of components that not only work independently but also communicate with each other. The catastrophic consequences of failures, such as loss of human lives, environmental damages, and financial losses, in many of these critical systems compel computer scientists and engineers to develop techniques for ensuring that these systems are implemented correctly despite of their complexity. Although a number of theories and software tools have been developed to support the formal description and verification of functional properties of systems, only in recent years the formal modeling and assessment of performance characteristics have received attention. This thesis addresses the problem of providing a suitable linguistic support which enables designers to formally describe and evaluate system performance in the early stages of system design, in order to avoid cost increases due to the late discovery of inefficiency. A reasonable solution should constitute a first step towards a methodology for the specification and analysis of computer, communication and software systems that achieves a reasonable balance among formality, expressivity, usability and efficiency. As a solution to the problem above, in this thesis we propose an integrated approach to modeling and analyzing functional and performance characteristics of systems which relies on formal description tech
Automated Compositional Markov Chain Generation for a PlainOld Telephone System
 SCIENCE OF COMPUTER PROGRAMMING
, 1999
"... Obtaining performance models, like Markov chains and queueing networks, for systems of significant complexity and magnitude is a di#cult task that is usually tackled using human intelligence and experience. This holds in particular for performance models of a highly irregular nature. In this paper w ..."
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Cited by 45 (25 self)
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Obtaining performance models, like Markov chains and queueing networks, for systems of significant complexity and magnitude is a di#cult task that is usually tackled using human intelligence and experience. This holds in particular for performance models of a highly irregular nature. In this paper we argue by means of a nontrivial example  a plainold telephone system (POTS)  that a stochastic extension of process algebra can diminish these problems by permitting an automatic generation of Markov chains. We introduce a stochastic process algebra that separates the advance of time and action occurrences. For the sake of specification convenience we incorporate an elapse operator that allows the modular description of time constraints where delays are described by continuous phasetype distributions. Using this language we provide a formal specification of the POTS and show how a stochastic process of more than 10 7 states is automatically obtained from this system description. ...
Turning back time in Markovian process algebra
 Theoretical Computer Science
, 1947
"... Productform solutions in Markovian process algebra (MPA) are constructed using properties of reversed processes. The compositionality of MPAs is directly exploited, allowing a large class of hierarchically constructed systems to be solved for their state probabilities at equilibrium. The paper cont ..."
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Cited by 43 (10 self)
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Productform solutions in Markovian process algebra (MPA) are constructed using properties of reversed processes. The compositionality of MPAs is directly exploited, allowing a large class of hierarchically constructed systems to be solved for their state probabilities at equilibrium. The paper contains new results on both reversed stationary Markov processes as well as MPA itself and includes a mechanisable proof in MPA notation of Jackson’s theorem for productform queueing networks. Several examples are used to illustrate the approach.
An algebraic approach to the specification of stochastic systems (extended abstract
 Programming Concepts and Methods
, 1998
"... ) P. R. D'Argenio 1 , J.P. Katoen 2 , and E. Brinksma 1 1 Dept. of Computer Science. University of Twente. P.O.Box 217. 7500 AE Enschede. The Netherlands. fdargenio,brinksmag@cs.utwente.nl 2 Lehrstuhl fur Informatik VII. University of ErlangenNurnberg. Martensstrasse 3. D91058 Erla ..."
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Cited by 41 (18 self)
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) P. R. D'Argenio 1 , J.P. Katoen 2 , and E. Brinksma 1 1 Dept. of Computer Science. University of Twente. P.O.Box 217. 7500 AE Enschede. The Netherlands. fdargenio,brinksmag@cs.utwente.nl 2 Lehrstuhl fur Informatik VII. University of ErlangenNurnberg. Martensstrasse 3. D91058 Erlangen. Germany. katoen@informatik.unierlangen.de Abstract We introduce a framework to study stochastic systems, i.e. systems in which the time of occurrence of activities is a general random variable. We introduce and discuss in depth a stochastic process algebra (named ) adequate to specify and analyse those systems. In order to give semantics to , we also introduce a model that is an extension of traditional automata with clocks which are basically random variables: the stochastic automata model. We show that this model and are equally expressive. Although stochastic automata are adequate to analyse systems since they are finite objects, they are still too coarse to serve as concrete semantic...
Parallel Performance Analysis of Large Markov Models
, 2000
"... Stochastic performance models provide a formal way of capturing and analysing the complex dynamic behaviour of concurrent systems. Such models can be speci ed by several highlevel formalisms, including Stochastic Petri nets, Queueing networks and Stochastic Process Algebras. Traditionally, perform ..."
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Cited by 38 (14 self)
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Stochastic performance models provide a formal way of capturing and analysing the complex dynamic behaviour of concurrent systems. Such models can be speci ed by several highlevel formalisms, including Stochastic Petri nets, Queueing networks and Stochastic Process Algebras. Traditionally, performance statistics for these models are derived by generating and then solving a Markov chain corresponding to the model's behaviour at the state transition level. However, workstation memory and compute power are often overwhelmed by the sheer number of states in the Markov chain and the size of their internal computer representations. This thesis presents two parallel and distributed techniques which signicantly increase the size of the models that can be analysed using Markov modelling. The techniques attack the space and time requirements of both major phases of the analysis, i.e. construction of the Markov chain from a highlevel model (state space generation) and solution of the Markov chain to determine its equilibrium