Yuqian #1 - Modelling and Simulation Flashcards
What is the definition of a system? How are systems and models related, and what are the three main types of models?
A system is a set of related components that are working together toward some purpose. We use models to analyse the system, where the model can be physical, analytical, or a simulation
Why do we use simulation models?
Simulation models are unique in their ability to handle both the randomness of most systems and the interdependence of the components in those systems.
Distinguish between static and dynamic simulations
Static: Passage of time plays no active/meaningful role in model execution
Dynamic: Passage of time essential and explicit in model execution
Distinguish between continuous-change and discrete-change simulations. What type of simulation models do these terms apply to?
Continuous-change: state variables can change continuously over time, at any point in continuous time
Discrete-change: state variables change only at instantaneous, separated, discrete points in time
These only apply to dynamic simulation models (not static)
Distinguish between deterministic and stochastic simulation models. What are two disadvantages of stochastic simulation?
Deterministic: All input values are fixed, non-random constants
Stochastic: Some inputs are random draws/samples from probability distributions. Disadvantages: answers are just statistical estimates with uncertainty/noise, and variation can be expected between different software packages.
Define the following four terms associated with discrete-event simulations: events, processes, objects, and agent-based
Events: model points in time when system state can change
Processes: model sequence of actions occurring over time
Objects: describe model from point of view of facility
Agent-based: intelligence given to objects to make them agents
