MPA: a Stochastic Process Algebra

Process algebras constitute one of the main tools for modeling and analyzing concurrent systems. Unfortunately, with classical process algebras only the functional aspect of the behavior of concurrent systems can be modeled and analyzed. Since the relevance of integrating the performance modeling and evaluation into the process of specification, design and implementation of concurrent systems has been widely recognized, an effort has been made in the field of the process algebras in order to handle also the temporal aspect of the behavior of concurrent systems. In this technical report the stochastic process algebraMPA (Markovian ProcessAlgebra) is defined together with its operational interleaving semantics and its markovian semantics. The operational interleaving semantics is defined by following the structured operational semantics approach augmented with two transformations. The markovian semantics is defined through an algorithm which transforms the automata representing the operational interleaving semantics of MPA terms into state transition rate diagrams of homogeneous continuous time Markov chains. Some examples are shown which demonstrate the expressiveness and the compositionality of MPA and the correctness of its semantics. Finally, MPA is compared with other stochastic process algebras already appeared in the literature. 1. Dipartimento di Matematica, Università di Bologna, Piazza di Porta S. Donato 5, 40127 Bologna, Italy.