7 research outputs found
A Process Calculus for Expressing Finite Place/Transition Petri Nets
We introduce the process calculus Multi-CCS, which extends conservatively CCS
with an operator of strong prefixing able to model atomic sequences of actions
as well as multiparty synchronization. Multi-CCS is equipped with a labeled
transition system semantics, which makes use of a minimal structural
congruence. Multi-CCS is also equipped with an unsafe P/T Petri net semantics
by means of a novel technique. This is the first rich process calculus,
including CCS as a subcalculus, which receives a semantics in terms of unsafe,
labeled P/T nets. The main result of the paper is that a class of Multi-CCS
processes, called finite-net processes, is able to represent all finite
(reduced) P/T nets.Comment: In Proceedings EXPRESS'10, arXiv:1011.601
A Formal Approach to Open Multiparty Interactions
We present a process algebra aimed at describing interactions that are
multiparty, i.e. that may involve more than two processes and that are open,
i.e. the number of the processes they involve is not fixed or known a priori.
Here we focus on the theory of a core version of a process calculus, without
message passing, called Core Network Algebra (CNA). In CNA communication
actions are given not in terms of channels but in terms of chains of links that
record the source and the target ends of each hop of interactions. The
operational semantics of our calculus mildly extends the one of CCS. The
abstract semantics is given in the style of bisimulation but requires some
ingenuity. Remarkably, the abstract semantics is a congruence for all operators
of CNA and also with respect to substitutions, which is not the case for strong
bisimilarity in CCS. As a motivating and running example, we illustrate the
model of a simple software defined network infrastructure.Comment: 62 page
The state operator in process algebra
+138hlm.;21c
Action Refinement in End-Based Choice Settings
The choice operator is essential for the description of action-based reactive systems. If the atomicity of actions is dropped (e.g. by action refinement), one has to decide when the choice is triggered. The standard approach is to trigger the choice when actions start. This thesis examine the alternative approach that the choice is triggered when actions terminate. This end-based choice is motivated and a process algebra, which contains an end-based choice and an action refinement operator, is established. Consistent semantics (operational, denotational, axiomatical) are given. Furthermore, the difference between the start-based and the end-based choice are examined, in particular with respect to equivalence notions. New equivalence are established, since the standard equivalences are not preserved by the end-based action refinement operator
An Operational Petri Net Semantics for A2CCS
ACCS is a conservative extension of CCS, enriched with an operator of strong prefixing,
enabling the modeling of atomic sequences and multi-party synchronization (realized as an atomic sequence of binary
synchronizations); the classic dining philosophers problem is used to illustrate the approach.
A step semantics for ACCS is also presented directly as a labeled transition system.
A safe Petri net semantics for this language
is presented, following the approach of Degano, De Nicola, Montanari and Olderog.
We prove that a process and its associated net \Net(p) are interleaving bisimilar (Theorem \ref{teo-inter}).
Moreover, to support the claim that the intended concurrency is well-represented in the net, we also prove that
a process and its associated net \Net(p) are step bisimila