A Graph Model for Basic Process Algebra

This was a lively scientific event, held in a relaxed workshop atmosphere that allowed for an informal, but intense, discussion of the status of research in the field of process algebra, broadly construed. The workshop witnessed the continuing vitality of this branch of concurrency theory, and we trust that, apart from being a celebration of over 20 years of research in this field, it contributed to its healthy development by highlighting some open problems, and possible new avenues for research.

Engineering Letters, 2007

ACP srt hs is a hybrid process algebra obtained by extending a combination of two existing extensions of Algebra of Communicating Processes (ACP), namely the process algebra with continuous relative timing and the process algebra with propositional signals, for the formal specification and analysis of hybrid systems. In addition to equational axioms, this hybrid process algebra has rules to derive equations with the help of real analysis. ACP srt hs is also closely related to the theory of hybrid automata, so ACP srt hs can be reasonable easily translated to hybrid automata. This enables automatic verification of ACP srt hs specifications using existing hybrid automaton-based verification tools (e.g. PHAVer and HyTech).

Acta informatica, 2001

Process algebras are a frequently used tool for the speci cation and veri cation of distributed reactive systems. In process algebras, actions are used to denote the basic entities of systems. In general, actions are just abstract names with no particular interpretation. The semantics of a system description, given in form of a process algebra term, is not in uenced by t h e c hoice of names. In this paper, we equip a process algebra with a simple semantics for the actions, given in the form of dependencies. The action dependencies are to beinterpreted in the Mazurkiewicz sense: independent actions should be able to commute, or from a di erent perspective should be unordered, whereas dependent actions are always ordered. In this approach, the operators are used to describe the conceptual behavioural structure of the system and the action dependencies determine the minimal necessary orderings and thereby the additionally possible parallelism within this structure.

Springer eBooks, 1992

In this paper we extend Real Time Process Algebra by the silent step r. We start by giving the operational semantics and we find a characterizing law of which the soundness and the completeness is proven. By adding the integral construct we can interpret symbolic (untimed) process terms as timed processes. We investigate the resulting r-equivalence and come to a delay bisirnulation with a stronger root condition. Finally we test the applicability of this notion of real time abstraction by proving the PAR protocol (Positive Acknowledgement with Retransmission) correct.

Information and Control, 1984

Within the context of an algebraic theory of processes, an equational specification of process cooperation is provided. Four cases are considered: free merge or interleaving, merging with communication, merging with mutual exclusion of tight regions, and synchronous process cooperation. The rewrite system behind the communication algebra is shown to be confluent and terminating (modulo its permutative reductions). Further, some relationships are shown to hold between the four concepts of merging.

Lecture Notes in Computer Science, 1991

1993

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Springer eBooks, 2019

arXiv (Cornell University), 2010

In this paper we introduced an algebraic semantics for process algebra in form of abstract data types. For that purpose, we developed a particular type of Σ algebra, the seed algebra, which describes exactly the behavior of a process within a labeled transition system. We have shown the possibility of characterizing the bisimulation of two processes with the isomorphism of their corresponding seed algebras. We pointed out that the traditional concept of isomorphism of algebra does not apply here, because there is even no one-one correspondence between the elements of two seed algebras. The lack of this one-one correspondence comes from the non-deterministic choice of transitions of a process. We introduce a technique of hidden operations to mask unwanted details of elements of a seed algebra, which only reflect non-determinism or other implicit control mechanism of process transition. Elements of a seed algebra are considered as indistinguishable if they show the same behavior after these unwanted details are masked. Each class of indistinguishable elements is called a non-hidden closure. We proved that bisimulation of two processes is equivalent to isomorphism of non-hidden closures of two seed algebras representing these two processes. We call this kind of isomorphism a deep isomorphism. We get different models of seed algebra by specifying different axiom systems for the same signature. Each model corresponds to a different kind of bisimulation. By proving the relations between these models we also established relations between 10 different bisimulations, which form a acyclic directed graph.

Lecture Notes in Computer Science, 1992

We present an overview and synthesis of existing results about process algebras for the specification and analysis of timed systems. The motivation is double: present an overview of some relevant and representative approaches and suggest a unifying framework for them. After presenting fundamental assumptions about timed systems and the nature of abstract time, we propose a general model for them: transition systems whose labels are either elements of a vocabulary of actions or elements of a time domain. Many properties of this model are studied concerning their impact on description capabilities and on realisability issues. An o.verview of the language features of the process algebras considered is presented, by focusing on constructs used to express time constraints. The presentation is organised as an exercise of building a timed process algebra from a standard process algebra for untimed systems. The overview is completed by a discussion about description capabilities according to semantic and pragmatic criteria.