Some Possibilities of Modeling Colored Petri Nets

Petri nets are a mathematical apparatus for modelling dynamic discrete systems. Their feature is the ability to display parallelism, asynchrony and hierarchy. First was described by Karl Petri in 1962 [1,2,8]. The Petri net is a bipartite oriented graph consisting of two types of vertices - positions and transitions connected by arcs between each other; vertices of the same type cannot be directly connected. Positions can be placed by tags (markers) that can move around the network. [2] Petri Nets (PN) used for modelling real systems is sometimes referred to as Condition/Events nets. Places identify the conditions of the parts of the system (working, idling, queuing, and failing), and transitions describe the passage from one state to another (end of a task, failure, repair...). An event occurs (a transition fire) when all the conditions are satisfied (input places are marked) and give concession to the event. The occurrence of the event entirely or partially modifies the status of the conditions (marking). The number of tokens in a place can be used to identify the number of resources lying in the condition denoted by that place [1,2,8]. Coloured Petri nets (CPN) is a graphical oriented language for design, specification, simulation and verification of systems [3-6,9,15]. It is in particular well-suited for systems that consist of several processes which communicate and synchronize. Typical examples of application areas are communication protocols, distributed systems, automated production systems, workflow analysis and VLSI chips. In the Classical Petri Net, tokens do not differ; we can say that they are colourless. Unlike standard Petri nets in Colored Petri Net of a position can contain tokens of arbitrary complexity, such as lists, etc., that enables modelling to be more reliable. The article is devoted to the study of the possibilities of modelling Colored Petri nets. The article discusses the interrelation of languages of the Colored Petri nets and traditional formal languages. The Venn diagram, which the author has modified, shows the relationship between the languages of the Colored Petri nets and some traditional languages. The language class of the Colored Petri nets includes a whole class of Context-free languages and some other classes. The paper shows modelling the task synchronization Patil using Colored Petri net, which can't be modeled using well- known operations P and V or by classical Petri network, since the operations P and V and classical Petri networks have limited mathematical properties which do not allow to model the mechanisms in which the process should be synchronized with the optimal allocation of resources.

Formal Security Evaluation and Improvement of Wireless HART Protocol in Industrial Wireless Network

With the rapid development of wireless communication technology in the field of industrial control systems, Wireless HART is an international wireless standard, because of its low cost and strong scalability, as well as its wide range of applications in the industrial control field. However, it is more open communication so that the possibility of increased attacks by external. At present, there are many types of research on wireless protocol security at home and abroad, but they all focus on the realization of the security function of the protocol itself, which has certain limitations for the formal modeling of the protocol security assessment. Taking into account the aforementioned research status, this paper takes the Wireless HART protocol as the research object and adopts the model detection method combining eCK model theory and colored Petri net theory to evaluate and improve the security of the protocol. First, the colored Petri net theory and CPN Tools modeling tool were introduced to verify the consistency of the original model of the protocol. And the eCK model was used to evaluate the security of the original protocol model. It was found that the protocol has two types of man-in-the-middle attack vulnerabilities: tampering and deception. Aiming at the attack loopholes of the protocol, an improvement plan was proposed. After improving the original protocol, CPN Tools modeling tool was used for security verification. It was found that the new scheme improvement can effectively prevent the existing attacks and reasonably improve the security of the protocol.

A Colored Petri Net-based modeling method for supply chain inventory management

Supply chain planning and control approaches need to include a wide range of factors in order to optimize production. Supply chain simulation modeling has been identified as a potential methodology toward increasing the efficiency of current systems to this end. The purpose of this paper is to evaluate the impact of inventory management decisions on supply chain performance using a Colored Petri Net based simulation modeling method. The presented method uses hierarchical timed Colored Petri Nets to model inventory management in a multi-stage serial supply chain, under normal operating conditions, and under the presence of disruptions, for both traditional and information sharing configurations. Disruptions are introduced as canceled orders and canceled deliveries, in a time period. Supply chain performance has been evaluated, in the context of order variance amplification and stockout amplification. Validation of the method is done by comparing results obtained for the bullwhip effect with published literature results, as well as by state space analysis results.

Overload Control in a Token Player for a Fuzzy Workflow Management System

The underlying proposal of this work is to control overload of a Token Player in a Fuzzy Workflow Management System. In order to accomplish this, possibility theory is used to measure how much the Token Player can be overloaded. The model used in this work is built using Colored Petri net and the simulation is made using CPN Tools. Finally, is possible to control overload of the Token Player in a Fuzzy Workflow Management System, nevertheless more time is spent to achieve the end of activities.