A simulation is the act of imitating the behavior of some situationor some real world process or system over period of time.

Simulation is technique for studing real world systems by representing there behavior using the model of the system.

A simulation may be performed through solving a set of equation, constructing a physical model or a computr graphic model.

Computer simulation can refer to a computer program that simulates an abstract model so that it can be studied and analyzed.

In computer simulation we first design model of actual or therotical physical system, then execute designed model on computer to analyze the output.

E.g. simulation of aircraft, simulation of inventory system, simulation of bank.

Consider operation of a bank as an e.g.,

Counting how many people come to the bank; how many tellers, how long each customer is in service; etc.

Establishing a model and its corresponding computer program.

Drawing conclusion:- increasing number of tellers, reducing service time, changing queing strategies, etc.