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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.
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
Towards Performance Evaluation with General Distributions in Process Algebras
 in Proc. of the 9th Int. Conf. on Concurrency Theory (CONCUR '98), LNCS 1466:405422
, 1998
"... . We present a process algebra for the performance modeling and evaluation of concurrent systems whose activity durations are expressed through general probability distributions. We first determine the class of generalized semiMarkov processes (GSMPs) as being the class of stochastic processes on w ..."
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Cited by 32 (12 self)
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. We present a process algebra for the performance modeling and evaluation of concurrent systems whose activity durations are expressed through general probability distributions. We first determine the class of generalized semiMarkov processes (GSMPs) as being the class of stochastic processes on which we must rely for performance evaluation to be possible. Then we argue that in this context the right semantics for algebraic terms is a variant of the ST semantics which accounts for both functional and performance aspects. The GSMP based process algebra we propose is introduced together with its formal semantics, an example of performance evaluation, and a notion of probabilistic bisimulation based equivalence accounting for action durations which is shown to be a congruence. 1 Introduction The aim of this paper is to develop a core calculus suitable for the performance evaluation of concurrent systems whose activity durations are expressed through general probability distributions. I...
A Formal Approach to the Integration of Performance Aspects in the Modeling and Analysis of Concurrent Systems
 Information and Computation
, 1998
"... A formal approach for modeling and analyzing concurrent systems is proposed which integrates performance characteristics in the early stages of the design process. The approach relies on both stochastically timed process algebras and stochastically timed Petri nets in order to exploit their compleme ..."
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Cited by 29 (13 self)
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A formal approach for modeling and analyzing concurrent systems is proposed which integrates performance characteristics in the early stages of the design process. The approach relies on both stochastically timed process algebras and stochastically timed Petri nets in order to exploit their complementary advantages. The approach is instantiated to the case of EMPA (Extended Markovian Process Algebra), introduced together with the collection of its four semantics and the notion of equivalence that are required in order to implement the approach. Finally, the case study of the alternating bit protocol is presented to illustrate the adequacy of the approach. 1
Compositional Asymmetric Cooperations for Process Algebras with Probabilities, Priorities, and Time
, 2000
"... The modeling and analysis experience with process algebras has shown the necessity of extending them with priority, probabilistic internal/external choice, and time in order to be able to faithfully model the behavior of real systems and capture the properties of interest. An important open problem ..."
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Cited by 28 (16 self)
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The modeling and analysis experience with process algebras has shown the necessity of extending them with priority, probabilistic internal/external choice, and time in order to be able to faithfully model the behavior of real systems and capture the properties of interest. An important open problem in this scenario is how to obtain semantic compositionality in the presence of all these mechanisms, to allow for an efficient analysis. In this paper we argue that, when abandoning the classical nondeterministic setting by considering the mechanisms above, a natural solution is to break the symmetry of the roles of the processes participating in a synchronization. We accomplish this by distinguishing between master actions – the choice among which is carried out generatively according to their priorities/probabilities or exponentially distributed durations – and slave actions – the choice among which is carried out reactively according to their priorities/probabilities – and by imposing that a master action can synchronize with slave actions only. Technically speaking, in this paper we define a process algebra called EMPAgr including probabilities, priorities, exponentially distributed durations, and the generative masterreactive slaves synchronization mechanism. Then, we prove that the synchronization mechanism in EMPAgr is correct w.r.t. the novel cooperation structure model, we show that the Markovian bisimulation equivalence is a congruence for EMPAgr, and we present a sound and complete axiomatization for finite terms. This paper is electronically published in
A calculus and logic of resources and processes
 FAC, 18:495 – 517
, 2006
"... Recent advances in logics for reasoning about resources provide a new approach to compositional reasoning in interacting systems. We present a calculus of resources and processes, based on a development of Milner's synchronous calculus of communication systems, SCCS, that uses an explicit mode ..."
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Cited by 24 (8 self)
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Recent advances in logics for reasoning about resources provide a new approach to compositional reasoning in interacting systems. We present a calculus of resources and processes, based on a development of Milner's synchronous calculus of communication systems, SCCS, that uses an explicit model of resource. Our calculus models the coevolution of resources and processes with synchronization constrained by the availability of resources. We provide a logical characterization, analogous to HennessyMilner logic's characterization of bisimulation in CCS, of bisimulation between resource processes which is compositional in the concurrent and local structure of systems.