Networked Modeling And Opacity Analysis Of Discrete Event System Based On Petri Net

With the rapid development of Internet and information technology,a new discrete event system is being studied.We call the discrete event system running in the shared network networked discrete event system.Network discrete event systems introduce a variety of delay effects in different application scenarios,and have more complex evolution behavior.Therefore,how to deal with the analysis and control of networked discrete event systems with delay is a hot topic in recent years.As an important secret attribute in discrete event systems,opacity can represent the defense capability of the system to prevent intruders from stealing system privacy.Therefore,the research and analysis of opacity is still an important research topic in the field of discrete event systems.With regard to the delay in networked discrete event systems,the purpose of this paper is to study the influence of transition delay on Petri net modeling and analysis.In the past,the modeling methods of timed Petri nets are mainly formal methods,which are relatively theoretical,which are not conducive to computer calculation and intuitive display of the impact of delay.And because the delay is not only caused by time,many delays can not be generalized with time,so it is necessary to choose to describe the impact of delay from other angles.The research and analysis of opacity in discrete event systems based on Petri nets is rare,and the method is mainly analyzed by reachable graph,but reachable graph has the problem of state explosion,which makes the research have a certain complexity.It is also necessary to overcome this limitation because the standard versions of current state opacity and initial state opacity do not perfectly represent higher privacy requirements.The main contents and innovations of this paper are summarized as follows:1)In order to solve the problem of transition delay in networked discrete event systems,a theoretical framework is established by using the matrix half tensor product,and the dynamic equation representation of networked Petri nets with fixed step transition delay is proposed.The sufficient and necessary conditions for the validation of the reversibility,activity and controllability of the networks are proposed.The results show that this method is more convenient for calculation.2)In order to solve the problem of opacity in discrete event systems,the current state observer of bounded Petri net logic system based on reachable graph theory is constructed,and a strong current state opacity verification condition based on parallel union operation is proposed.In order to avoid the problem of state explosion,the construction method of state estimator based on generalized basis reachable graph is further extended,and a new verification condition for strong current state opacity of bounded Petri net logic systems is given.