Slide 13: Introduction to Simulation g Event-driven simulation: simulation is centered around events that occur as a consequence of activities or delays. Simulation keeps track of events that are assumed to occur in(simulated) future, and update system states and move the simulation clock as events occur sequentially. Need a mechanism to determine and control o What type of event to occur?(adding new event o Which event should be scheduled to occur next? o What to do when an event occurs?(e.g. updating system states and statistical accumulators)
Event-driven simulation: simulation is centered around events that occur as a consequence of activities or delays. Simulation keeps track of events that are assumed to occur in (simulated) future, and update system states and move the simulation clock as events occur sequentially. Need a mechanism to determine and control: ⚫ What type of event to occur ? (adding new event) ⚫ Which event should be scheduled to occur next? ⚫ What to do when an event occurs? (e.g. updating system states and statistical accumulators) Slide 13: Introduction to Simulation
Slide 14: Introduction to Simulation G Event transition/interaction diagram Arrival Departure Event-driven simulation logic flow chart
Event transition/interaction diagram Event-driven simulation logic flow chart Slide 14: Introduction to Simulation Arrival Departure
Slide 15: Introduction to Simulation e Process-oriented simulation: this approach emulates the flow of an entity through the system, i.e. centers on the process that the entity undergoes. Consider main steps that an entity goes through a single server M/M/1 simulation process Create itself(mark the time-in) o Wait in queue for a resource Seize the resource(take itself out of the queue o Delay a duration equal to its service time Release the resource e Increment production-counter/accumulator and tally flow time Dispose itself and leave the system
Process-oriented simulation: this approach emulates the flow of an entity through the system, i.e. centers on the process that the entity undergoes. Consider main steps that an entity goes through a single server M/M/1 simulation process: ⚫ Create itself (mark the time-in) ⚫ Wait in queue for a resource ⚫ Seize the resource (take itself out of the queue) ⚫ Delay a duration equal to its service time ⚫ Release the resource ⚫ Increment production-counter/accumulator and tally flow time ⚫ Dispose itself and leave the system Slide 15: Introduction to Simulation