This chapter provides an introduction to Petri nets. Petri nets are an excellent formal model for studying concurrent and distributed systems and are widely applied in many different areas of computer science and other disciplines Petri nets are also extended in many different ways to study specific system properties, such as performance, reliability, and schedulability. Well-known examples of extended Petri nets include timed Petri nets and stochastic Petri nets. Petri nets are a model-oriented formal method and are well suited for modeling the dynamic behaviors of concurrent and distributed systems. Petri net specifications reveal system design structures and thus provide guidelines for system implementation. Furthermore, Petri net specifications are executable and support system simulation and testing in addition to formal analysis. This chapter presents several extensions to Petri nets based on the research work and provides analysis techniques for these extended Petri net models. It also discusses the intended applications of these extended Petri nets and their potential benefits.
