Verification and Validation of Simulation Models
- Verification: concerned with building the model right. It is utilized in the comparison of the conceptual model to the computer representation that implements that conception.
- It asks the questions: Is the model implemented correctly in the computer? Are the input parameters and logical structure of the model correctly represented?
- Validation: concerned with building the right model. It is utilized to determine that a model is an accurate representation of the real system. Validation is usually achieved through the calibration of the model, an iterative process of comparing the model to actual system behavior and using the discrepancies between the two, and the insights gained, to improve the model. This process is repeated until model accuracy is judged to be acceptable.
Verification of Simulation Models
Many common sense suggestions can be given for use in the verification process.
- Have the code checked by someone other than the programmer.
- Make a flow diagram which includes each logically possible action a system can take when an event occurs, and follow the model logic for each action for each event type.
- Closely examine the model output for reasonableness under a variety of settings of the input parameters. Have the code print out a wide variety of output statistics.
- Have the computerized model print the input parameters at the end of the simulation, to be sure that these parameter values have not been changed inadvertently.
- Make the computer code as self-documenting as possible. Give a precise definition of every variable used, and a general description of the purpose of each major section of code.
These suggestions are basically the same ones any programmer would follow when debugging a computer program.
Calibration and Validationof Models
Optimization is the appropiate technology to combine of values for the variable that can be controlled to seek the combination of value that provide the most desirable output from the simulation model.
The way to find the optimal solution is follow some steps:
- Identify all possible decision variables that affect the output of the system
- Based on the possible values of each decision variable, identify all possible solutions
- Evaluate each of these solutions accurately
- Compare each solution fairly
- Record the best answer
Here I provide you the video that represent how to verify and validate the model simulation