Discrete event simulation (DES).

Discrete event simulation (DES) is a way of taking the functions of a multifaceted system, breaking those functions down into individual components that occur in a specific order, and then coding them in such a way that they can be replicated. This process allows computers to be programmed to repeat the behavior so that it can be analyzed. DES provides a way that systems can be altered and adjusted to simulate variations in the system's functions so that the effects of these changes can be studied, problems in systems can be identified, and people can be trained or tested on the system and its functions.