Synthesising ENI-Systems with Interval Order Semantics

\ua9 2024 Copyright for this paper by its authors. Elementary net systems with inhibitor arcs are a class of fundamental Petri net models with very simple markings which are sets of places. Their standard semantics is based on sequences of executed transitions or, alternatively, as labelled total orders. In this paper, we introduce semantics based on interval (partial) orders which allows one to describe behaviours where transitions have non-atomic duration. For such a semantical model, we consider the net synthesis problem, and show that the standard notion of a region of transition system (providing input to the synthesis procedure) can still be applied after suitable modifications

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

A Flow Sensitive Security Model for Cloud Computing Systems

A flow sensitive security model is presented to analyse information flow in federated cloud systems. Each cloud and the entities of the cloud system are classified into different security levels which form a security lattice. Opacity --- a general technique for unifying security properties --- turns out to be a promising analytical technique in the context of cloud computing systems. The proposed approach can help to track and control the secure information flow in federated cloud systems. It can also be used to analyze the impact of different resources allocation strategies

Opacity in Internet of Things with Cloud Computing

The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.Internet of Things (IoT) with Cloud Computing (CC) is a new paradigm incorporating a pervasive presence of a wide range of things/objects which can interact with each other and cooperate, creating new services and reaching common goals. This will lead to more intelligent smart environments in a wide range of applications. In this context, protecting the Internet of Things with Cloud Computing (IoTwCC) against interference, including service attacks and viruses, becomes paramount. In this paper, we introduce a transition system representation to capture the information flow in IoTwCCs, and then investigate the opacity of the information flow model. In addition, we introduce a threat model to describe the actions of the system, and propose entropy as a security metrics to quantify the amount of information related to a service that might be exposed to other users or adversaries. It turns out that the opacity of the system is affected by the availability of the services. As a result, the trade-off between opacity and service availability can be analyzed

Relational structures for concurrent behaviours

\ua9 2020 The Author(s). Relational structures based on acyclic relations can successfully model fundamental aspects of concurrent systems behaviour. Examples include Elementary Net systems and Mazurkiewicz traces. There are however cases where more general relational structures are needed. In this paper, we present a general model of relational structures which can be used for a broad class of concurrent behaviours. We demonstrate how this general set-up works for combined order structures which are based on two relations, viz. an acyclic ‘before’ relation and a possibly cyclic ‘not later than’ relation

Classifying Invariant Structures of Step Traces

In the study of behaviours of concurrent systems, traces are sets of behaviourally equivalent action sequences. Traces can be represented by causal partial orders. Step traces, on the other hand, are sets of behaviourally equivalent step sequences, each step being a set of simultaneous actions. Step traces can be represented by relational structures comprising non-simultaneity and weak causality. In this paper, we propose a classification of step alphabets as well as the corresponding step traces and relational structures representing them. We also explain how the original trace model fits into the overall framework.Algorithms and the Foundations of Software technolog

Petri Nets for Biologically Motivated Computing

Petri nets are a general and well-established model of concurrent and distributed computation and behaviour, including that taking place in biological systems. In this survey paper, we are concerned with intrinsic relationships between Petri nets and two formal models inspired by aspects of the functioning of the living cell: membrane systems and reaction systems. In particular, we are interested in the benefits that can result from establishing strong semantical links between Petri nets and membrane systems and reaction systems. We first discuss Petri nets with localities reflecting the compartmentalisation modelled in membrane systems. Then special attention is given to set-nets, a new Petri net model for reaction systems and their qualitative approach to the investigation of the processes carried out by biochemical reactions taking place in the living cell