1,721,102 research outputs found
Language representability of finite place/transition Petri nets
No full textFinite-net multi-CCS is a CCS-like calculus which is able to model atomic sequences of actions and, together with parallel composition, also multi-party synchronization. This calculus is equipped with a labeled transition system semantics and also with an unsafe P/T Petri net semantics, which is sound w.r.t. the transition system semantics. For any process p of the calculus, the net associated to p by the semantics has always a finite number of places, but it has a finite number of transitions only for so-called well-formed processes. The main result of the paper is that well-formed finite-net multi-CCS processes are able to represent all finite, statically reduced, P/T Petri nets
Process algebras for petri nets: the alphabetization of distributed systems
No full textThis book deals with the problem of finding suitable languages that can represent specific classes of Petri nets, the most studied and widely accepted model for distributed systems. Hence, the contribution of this book amounts to the alphabetization of some classes of distributed systems. The book also suggests the need for a generalization of Turing computability theory
Introduction to Concurrency Theory - Transition Systems and CCS
No full textThis book presents the fundamentals of concurrency theory with clarity and rigor. The authors start with the semantic structure, namely labelled transition systems, which provides us with the means and the tools to express processes, to compose them, and to prove properties they enjoy. The rest of the book relies on Milner's Calculus of Communicating Systems, tailored versions of which are used to study various notions of equality between systems, and to investigate in detail the expressive power of the models considered.
The authors proceed from very basic results to increasingly complex issues, with many examples and exercises that help to reveal the many subtleties of the topic. The book is suitable for advanced undergraduate and graduate students in computer science and engineering, and scientists engaged with theories of concurrency
Language representability of finite P/T nets
No full textFinite-net Multi-CCS is a CCS-like calculus which is able to model atomic sequences of actions and, together with parallel composition, also multi-party synchronization. This calculus is equipped with a labeled transition system semantics and also with an unsafe P/T Petri net semantics, which is sound w.r.t. the transition system semantics. For any process p of the calculus, the net associated to p by the semantics has always a finite number of places, but it has a finite number of transitions only for so-called well-formed processes. The main result of the paper is that well-formed finite-net Multi-CCS processes are able to represent all finite, statically reduced, P/T Petri nets
Formal Performance Modelling and Evaluation of an Adaptive Mechanism for Packetised Audio over the Internet
No full textA case study is presented which concerns the design of an adaptive mechanism for packetized audio for use over the Internet. During the design process, the audio mechanism was modeled with the stochastically timed process algebra EMPA and analyzed via simulation by the EMPA based software tool TwoTowers in order to predict the percentage of packets that are received in time for being played out. The predicted performance figures obtained from the algebraic model illustrated in advance the adequacy of the approach adopted in the design of the audio playout delay control mechanism. Based on these performance figures, it was possible to implement and develop the complete mechanism without incurring in additional costs due to the late discovery of unexpected errors or inefficiency. Performance results obtained from experiments conducted on the field confirmed the predictive simulative results
An Algebraic Model for Evaluating the Performance of an ATM Switch with Explicit Rate Marking
No full textStochastically timed process algebras are emerging as a promising formalism to support performance modeling and evaluation of concurrent and distributed systems. To become well accepted, such formalisms have to be proved to be able to provide readable, modular, scalable formal descriptions of more and more complex systems which can be automatically analyzed with a reasonable computational effort. To this aim, we present an algebraic model of an ATM switch which supports the four service categories defined by the ATM Forum and implements explicit rate marking for ABR traffic, backward explicit congestion notification, and connection admission control. As performance measures of interest, we assess via simulation the cell loss ratio, the mean queue length, and the link utilization for the outgoing link in several different configurations
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