Serge Haddad

On Well-Formed Coloured Nets and Their Symbolic Reachability Graph

The new class of Well Formed Coloured Nets (WN) is formally defined as an extension of Regular Nets (RN), together with an extended Symbolic Reachability Graph (SRG) construction algorithm. WNs allow the representation of any colour function in a structured form, so that they have the same modelling power as general coloured nets (CPN). In particular, with respect to RN, WNs allow the use of non-symmetric initial markings, of repeated occurrences of the same basic class in the Cartesian product defining the colours for transitions and places, and of the “constant” and “successor” functions as arc labels. The SRG allows colour symmetries to be exploited to reduce the space and time complexity of the analysis by reachability graph. The advantage of using WNs instead of unconstrained CPNs is that the detection of symmetries to construct the SRG is totally algorithmic, and requires no special heuristics.

Open protocol design for complex interactions in multi-agent systems

This paper proposes a generic approach or protocol engineering through the analysis,the specification,and the verification of such protocols when several agents are involved. This approach is three folds:1)Starting from semi-formal specification by means o Protocol Diagrams (AUML),both formal specification of interaction protocols and their verification are allowed thanks to Colored Petri Nets (CPN);2) Debugging and qualitative analysis o interactions are based on distributed observation associated with the true concurrency semantics (i.e.CPN unfolding)and ;3)CPN formalism is extended to Recursive CPN (RCPN)with abstraction in order to deal with open protocols.The main interest of abstraction is the design of fexible protocols giving agents more autonomy during interaction.In addition,abstraction allows concise modeling and easier verification. measures,performance measures .

A symbolic reachability graph for coloured Petri nets

Coloured Petri nets are well suited to the modelling of symmetric systems. Model symmetries can be usefully exploited for the sake of analysis efficiency as well as for modelling convenience. We present a reduced reachability graph called symbolic reachability graph that enjoys the following properties: (1) it can be constructed directly by an efficient algorithm without considering the actual state space of the model; (2) it can be substantially smaller than the ordinary reachability graph; (3) its analysis provides equivalent results as the analysis of the ordinary reachability graph. The construction procedure for the symbolic reachability graph is completely effective in the case of a syntactically restricted class of coloured nets called “well-formed nets”, while for the unrestricted case of coloured nets some procedures may not be easily implementable in algorithmic form.

Comparison of the expressiveness of timed automata and time petri nets

In this paper we consider the model of Time Petri Nets (TPN) where time is associated with transitions. We also consider Timed Automata (TA) as defined by Alur & Dill, and compare the expressiveness of the two models w.r.t. timed language acceptance and (weak) timed bisimilarity. We first prove that there exists a TA

A reduction theory for coloured nets

\mathcal{A}

Comparison of different semantics for time petri nets

s.t. there is no TPN (even unbounded) that is (weakly) timed bisimilar to

Design and Evaluation of a Symbolic and Abstraction-Based Model Checker

\mathcal{A}

Theoretical Aspects of Recursive Petri Nets

. We then propose a structural translation from TA to (1-safe) TPNs preserving timed language acceptance. Further on, we prove that the previous (slightly extended) translation also preserves weak timed bisimilarity for a syntactical subclass

Timed Petri nets and timed automata: On the discriminating power of zeno sequences

\mathcal{T}_{syn}(\leq,\geq)

Recursive Petri nets: Theory and application to discrete event systems

of TA. For the theory of TPNs, the consequences are: 1) TA, bounded TPNs and 1-safe TPNs are equally expressive w.r.t. timed language acceptance; 2) TA are strictly more expressive than bounded TPNs w.r.t. timed bisimilarity; 3) The subclass