Design And Implementation Of Structural Properties Of Petri Nets Analysis Tool

Petri net,as a modeling tool,is one of the main tools for modeling and analysis of discrete event systems.Typical discrete event systems include flexible manufacturing systems,semiconductor production lines,etc.Deadlocks caused by improper resource allocation in flexible manufacturing systems can directly lead to deterioration of productivity.Deadlock avoidance has been a primary methodologies for handling deadlocks in Petri nets.Siphons are a structural object of Petri nets,in theory,their number has an exponential relationship with the net size.In order to avoid deadlock,we should control every emptying siphon,then we need to enumerate all minimal siphons.Due to the complexity of the system,the structure of Petri net is increasingly complex.Manual analysis is far from enough to meet the requirements,so Petri net analysis software comes into being.Now there are a lot of analysis software for Petri nets,but these analysis software have certain limitation,the function is not perfect,can only do some simple analysis to Petri net,such as the activity,the boundedness and so on.Therefore,this thesis designed a Petri net analysis software which has a lot of functions.In this thesis,a Petri net tool with its own characteristics is developed based on the research status of the modeling analysis software of Petri net at home and abroad as well as the algorithm that the research group needs and the team has formed over the years.Then the functions of each module are implemented in Eclipse development environment with the method of object oriented analysis and with the Java programming language.It is possible to get an effective method of discrete event system with modeling and analysis with combining the object-oriented technology and Petri net and making full use of object oriented technology advantages and Petri net modeling method on the powerful mathematical analysis ability.Firstly,this thesis discussed the basic theory of Petri net and object-oriented technology,including the definition of Petri nets,subclass of Petri nets and object-oriented technology.Secondly,this thesis expounded the overall function of module of Petri nets analysis software and the design and data structure of basic classes,According to the idea of object oriented and the characteristics of Petri nets and the subclasses,elements of Petri nets are abstracted as corresponding classes.The basic classes in Petri net adopt the generic design method,and the design of generics improves the security of the program.Then by using object oriented technology and Java programming language to achieve various analysis modules.Lastly,this thesis completed the analysis to the structure of system of simple sequential process with resources(S~3PR)nets,linear system of simple sequential process with resources(LS~3PR)nets and ordinary nets:studying the structure of S~3PR nets,mainly through the method of removing points of the initial resources directed graph of S~3PR nets,then we can get the strict minimal siphons(SMSs),the number of elementary siphons(ESs)and a set of ESs of an S~3PR net.Studying the structure of LS~3PR nets,through the method of removing points from the initial resources directed graph of LS~3PR nets,then we can get all SMSs,the number of ESs and a set of ESs of an LS~3PR net.Studying the structure of ordinary Petri nets,we calculating all the minimal siphons of an ordinary Petri net.