An Introduction to the Macro Cosy Notation

The PETRI NETS 2023 proceedings deal with the application and theory of petri nets, distributed and concurrency systems, etc.

Firstly, net theory, which is a well established theory of distributed systems and processes [I] relies heavily on a graphical notation. One of the strengths of this theory is that many of the fundamental notions concerning concurrent systems and in particular, the dynamics of a concurrent systemcan be made transparent with the help of simple net diagrams and transformations of such diagrams. It is important to provide a solid formal foundation to this aspect of net theory and graph grammars appear to be the obvious tool for doing so. The second motivation is that in the study of concurrency problems that arise within the area of graph grammars [2] we think it is possible and fruitful to apply the concepts and techniques of net theory.

Petri nets have proven to be a valuable tool for modelling concurrent systems. As such, they should be suitable for modelling agent and multi-agent systems, as these are inherently concurrent. Nevertheless, there are not many systems that allow modelling of the whole multi-agent system in Petri nets. The use of Petri nets is usually limited to sub-problems, such as verification of interaction protocols. This paper describes the main concepts of PNagent - a tool for modelling BDI agents using the formalism of object oriented Petri nets (OOPN). PNagent allows development, testing and running software agents in a consistent graphical environment. The framework is suitable for prototyping and experiments with both multi-agent applications and the particular agent architecture itself. At the same time, thanks to the formal nature of its underlying paradigm, it provides means for verification of agentpsilas properties.

Concurrency is a difficult subject to teach and learn. This paper presents a set of recipes for the use of Petri nets as a teaching aid of some fundamental concurrency concepts, in the context of an introductory concurrent programming course. Classroom experience clearly demonstrates this usage of Petri nets improves students understanding of concurrency concepts.

Petri Nets are tools for the modelling and analysis of the behaviour of systems and analysis of the Petri Net can then reveal important information about the structure and dynamic behaviour of the modelled system. In this article, the author argues that Petri Net concepts (when used qualitatively) are not fundamentally different from those of ANT. For example, the ‘places’ from Petri Nets bear a strong resemblance to the actors in ANT, and the ‘triggers’ or ‘transitions’, are somewhat analogous to ANT’s translations. In modelling, places represent conditions and transitions represent events. Tokens may model the resources or data items that are associated with a place or places. The original research that this article is based on was undertaken using an actor-network framework to develop a model for e-Learning for students with Learning Difficulties. This article explores the qualitative use of Petri Nets to supplement this ANT treatment.

Petri nets have proved their effectiveness in modeling and formal verification of a large number of applications: control systems, communication protocols, application workflows, hardware design, etc. In the present days, one important focus of computer science is on security and secure communications. The use of Petri nets for verifying security properties is not a mature field due to a lack of convenient modeling and verification capabilities. So far, in the Petri Net field there is only CPN Tools that is mature enough for modeling, using the colored Petri nets formalism. Nevertheless such verifications cannot be performed on large systems as CPN Tools is based on an exhaustive way of computing the semantics of a model. In this paper we present the use of AlPiNA, another candidate for this task. AlPiNA is a symbolic model checker that uses the formalism of algebraic Petri nets. We have used it successfully for modeling ad hoc networks and for verifying security protocols designed for this type of networks. As a case study and benchmark we have chosen the ARAN secure routing protocol. We managed to find all the attacks that were already reported for this protocol. To our knowledge this work is also the first successful attempt to use Petri nets for model checking the security properties of ad hoc networks protocols.

Petri Nets are tools for the modelling and analysis of the behaviour of systems and analysis of the Petri Net can then reveal important information about the structure and dynamic behaviour of the modelled system. In this article, the author argues that Petri Net concepts (when used qualitatively) are not fundamentally different from those of ANT. For example, the ‘places’ from Petri Nets bear a strong resemblance to the actors in ANT, and the ‘triggers’ or ‘transitions’, are somewhat analogous to ANT’s translations. In modelling, places represent conditions and transitions represent events. Tokens may model the resources or data items that are associated with a place or places. The original research that this article is based on was undertaken using an actor-network framework to develop a model for e-Learning for students with Learning Difficulties. This article explores the qualitative use of Petri Nets to supplement this ANT treatment.

The use of Petri nets for modelling, analysing and simulating complex distributed production systems meets serious problems when the size of the model grows. Therefore, it would be very useful to decompose a Petri net based model into smaller models linked with one another. The aim of this paper is to suggest and discuss some possible definitions of Modular Petri nets. This is accomplished by introducing the concept of Petri subnet. Two possible definitions are proposed and the meaning and the usefulness with respect to both model definition and model executability for simulation are pointed out. All definitions are given for the basic model of Petri nets. The extension of modularity concepts to high level Petri nets is shown to be possible in the second part of the paper, where an application is illustrated. In particular an algorithm is given which allows automatic composition of subnets into a larger model

Half a century after Carl Adam Petri’s Ph.D. thesis: A perspective on the field

The demand for energy is constantly growing: analysts forecast that it will increase by 50% by 2040. New deposits being discovered and the elaboration of new methods of hydrocarbons extraction will allow using these resources for a long time. Nevertheless, most countries have begun to think about using solar power. This interest is caused not only by environmental problems, but also by the fact that annually 178.000 TW of solar radiation reaches our planet. To use solar energy, two methods – thermal and photovoltaic – are used. The first one involves heating up used liquid, the second one implies the conversion of sunlight into electrical energy. Containers for storing fossil fuels are installed at oil terminals. This hydrocarbon can be crude or refined oil in a form of heavy (mazut) or light (diesel) fuel. Solar energy can be used at oil terminals both for heating hydrocarbons (in order to reduce viscosity to operating parameters), and for storing electrical power. The use of solar energy will improve energy efficiency and the environmental component of a terminal. The paper presents the functioning of an oil product heating system as a sequence of events based on cause-effect relations. For a formal description of the logical structure of processes of solar energy use, the authors proposed a solution using the Petri net machine. Prerequisites for the use of Petri nets are: the presence of random and deterministic components in the process of generation of solar energy; the possibility of representing the conversion of solar energy in the form of sets of technologically homogeneous parallel processes; situational control related to the randomness of the possibility of converting solar energy. With the help of the model and by using the Petri net, conflict situations were found that could be solved by situational control. As practice shows, such kind of local situations is solved within the framework of automated control.

Risk of pedestrian while crossing a road section may influence by several factors, including their crossing behaviors which might be difficult to be measured. In this paper, a model using Petri nets is introduced to consider the behavioral factors in measuring pedestrian risk. The crossing scenario of the pedestrian was observed to identify the pedestrian accident event. Sequence of event in pedestrian accident was modeled into Petri Nets elements. The model is designed in the hierarchical structure to consider risk factors related to human behavior, engineering and environment. The analysis of the model provides the numerical value of pedestrian potential risk as they crossed at a signalized intersection. The effect of each factor on the potential risk can be observed through sensitivity analysis. The use of Petri Nets is a novel approach in predicting pedestrian potential risk through the modeling of pedestrian accident process.

Unmanned aerial vehicle safety assessment modelling through petri Nets

The sweep-line state space exploration method

The paper presents a notion of preorder with related equivalence between concurrent systems which supports functional abstraction and refinement. Such abstraction and refinement disregard action names (the action alphabet can be changed) while they require to preserve local state transformations. Since Petri Nets explicitly model both states and state transformations, concurrent systems are considered as modelled by Petri nets, precisely by contact-free Elementary Net systems in which some states are observable (S-labelled systems). The proposed preorder, called State transformation (ST) preorder, is defined on the basis of morphisms between the OLST-algebras associated to the compared systems. OLST-algebras describe the state space of S-labelled systems characterizing system behaviour in terms of observable local state transformations. The paper presents the construction of the unique canonical representative of each ST-equivalence class of S-observable systems, a subclass of S-labelled systems, and discusses ST-preorder and equivalence over S-observable systems in the framework of system development.

This paper presents a unified design environment of concurrent logic controllers, based on the use of Petri nets, rule-based description languages and PL4 specification languages (especially AMD Palasm 4). The straightforward templates are presented that made possible a rule-based Petri net specification to be simulated and then efficiently synthesised with modern programmable devices. Though the example presented in this paper is relatively trivial, the concepts are directly applicable in the more realistic designs.