Definition
Simulation is the process of executing a model over time to imitate the operation of a real-world process or system. It is a “time-varying representation of a model” that allows for the generation of a history (real or artificial) to draw inferences about the operating characteristics of the system.
Why It Matters
Defining simulation as a ‘time-varying representation’ distinguishes it from static analysis; it highlights that we are not just studying a system’s structure, but its behavior over time, which is the only way to predict dynamic failures.
Core Concepts
- Temporal Aspect: Simulation adds time to a static model. It can run in “Wall Clock Time” (real time), compressed time (faster), or expanded time (slower).
- Simulation Viewpoint: The perspective of the entity moving through the system: Arrival → Queue → Seize → Release → Disposal.
- Simulation vs. Training Simulators:
- Simulation Models: Analyze systems and resource/operating policy decisions (decisions made beforehand).
- Training Simulators: Train users for real-time decision-making during the run (e.g., CNC machinery, emergency response).
- Purposes: Gaining insight without stopping the system, testing new concepts before capital investment, and experimenting without disturbance.