simulation:

It is the imitation of the operation of a real world process or system over time. It is acting out or mimicking an actual or probable real life condition, event or situation to find a cause of a past occurrence or to forecast future effects of assumed circumstances or factors.

It is used to describe and analyze the behavior of a system.

e.g. flight simulator,

When simulation is an appropriate tool:

1. It enables one to study internal interactions of a complex system or of a subsystem within a complex system.

2. The effect of information, organization and environmental changes on the model's behavior can be simulated and observed.

3. The performance of the system under investigation can be improved by knowledge gained from simulations.

4. Simulation results can help to find which variables are the most important ones and how variables interact.

5. It can be used as a learning tool.

6. It can be used to verify analytical solutions.

7. By simulating diff. capabilities for m/c, re. can be determined.

8. Simulation models designed for training allow learning without any cast.

9. simulation in the form of animation can show the system in action, so that the plan can be visualized.

10. The interactions in modern complex system like factory, water fabrication, etc. can be treated only through simulation.

When simulation is not appropriate tool:

1. problem is solvable by common sense.

2. problem can be solved mathematically.

3. Direct experiments are easier.

4. Simulation costs exceed the savings.

5. Simulation requires time which is not available.

6. No i/p data is available and simulation need data.

7. Simulation cannot be verified and validated.

8. system behavior is too complex or unknown..