Synthesis of Petri Nets with Localities

Automated synthesis from behavioural specifications is an attractive way of constructing computational systems. In this paper, we look at a specific instance of this approach which aims at constructing GALS (globally asynchronous locally synchronous) systems. GALS systems are represented by Petri nets with localities, each locality defining a set of co-located actions, and specifications are given in terms of transition systems with arcs labelled by steps of executed actions. The proposed synthesis procedures are based on the regions of transition systems, and work without knowing which actions are to be co-located. We consider two basic classes of Petri nets, viz. Elementary Net System with Localities (ENL-system) and Place/Transition nets with localities (PTL-nets). In particular, we discuss ENL-systems where there is no conflict between events coming from different localities. In such a case, the synthesis problem reduces to checking just one co-location relation. This result is then extended to PTL-nets

Adding A/Sync Places to the Synthesis Procedure for Whole-Place Operations Nets with Localities

Algorithms and the Foundations of Software technolog

Signal set tissue systems and overlapping localities

Algorithms and the Foundations of Software technolog

Towards an Algebra of Abstractions for Communicating Processes

It is often desirable to describe the interface of an implementation system at a different (usually more detailed) level of abstraction to the interface of the relevant specification. This calls for a relation aimed at formalising the notion that a process is an acceptable implementation of another target process in the event that they possess different interfaces. We conduct our investigation in the standard failures-divergences CSP process model, formulating a suitable implementation relation between the observable behaviours of the implementation and the target process. Interface difference and bridging is modelled by endowing the implementation relation with parameters, called extraction patterns, instrumental to interpreting implementation behaviour as target behaviour. Reasonable notions of implementation and extraction patterns should result in a relation satisfying the realisability and compositionality properties. The former means that, if target and implementation in fact have the same interface, then th

Synthesis of General Petri Nets with Localities

There is a growing need to introduce and develop computational models capable of faithfully modelling systems whose behaviour combines synchrony with asynchrony in a variety of complicated ways. Examples of such real-life systems can be found from VLSI hardware GALS systems to systems of cells within which biochemical reactions happen in synchronised pulses. One way of capturing the resulting intricate behaviours is to use Petri nets with localities where transitions are partitioned into disjoint groups within which execution is synchronous and maximally concurrent. In this paper, we generalise this type of nets by allowing each transition to belong to several localities. Moreover, we define this extension in a generic way for all classes of nets defined by net-types. We show that Petri nets with overlapping localities are an instance of the general model of nets with policies. Thanks to this fact, it is possible to automatically construct nets with localities from behavioural specifications given in terms of finite step transition systems. After that we outline our initial ideas concerning net synthesis when the association of transitions to localities is not given and has to be determined by the synthesis algorithm

M.: Transition systems of elementary net systems with localities

In this paper, we investigate transition systems of a class of Petri nets suitable for the modelling and behavioural analysis of globally asynchronous locally synchronous (GALS) systems. The considered model of Elementary Net Systems with Localities (ENL-systems) is basically that of Elementary Net Systems (EN-systems) equipped with an explicit notion of locality. Each locality identifies a distinct set of events which may only be executed synchronously, i.e., in a maximally concurrent manner. For this reason, the overall behaviour of an ENL-system cannot be represented by an interleaved transition system, with arcs being labelled by single events, but rather by a suitable notion of a step transition system, with arcs being labelled by sets of events executed concurrently. We completely characterise transition systems which can be generated by Elementary Net Systems with Localities under their intended concurrency semantics. In developing a suitable characterisation, we follow the standard approach in which key relationships between a Petri net and its transition system are established via the th