The document discusses system simulation. It defines key terms like system, model, modeling, and simulation. It explains that a simulation experiments with a model of a system rather than the actual system. There are different types of simulations - discrete-event vs continuous, deterministic vs stochastic. Simulation can be done by hand, with spreadsheets, programming languages, or simulation packages. The steps in developing a simulation model are outlined. Advantages include understanding systems without using real-time systems and testing changes. Disadvantages include requiring expertise and being time-consuming. Dimensional analysis using Buckingham's π-theorem is also summarized.