Discrete Event Systems (DES) are systems where changes occur at distinct points in time, triggered by specific events. These events can include arrivals, departures, or any significant changes in the system's state. DES are commonly used in various fields, such as manufacturing, telecommunications, and computer networks, to model and analyze processes. In a DES, the system's behavior is often represented using state diagrams or event-driven simulations. This allows for the examination of how events interact and affect the overall system performance. Tools like Petri nets and Markov chains are frequently employed to study these systems and optimize their efficiency.