Model-based reasoning is used as the basis of all diagnostic applications built in iTech.

It uses the logical connections between components with forward and backward chaining and the optimization techniques described under the section diagnostic principles to dynamically update and optimize its diagnostic strategy or test pattern.

This section describes how to apply these modeling principles for use in iTech.

There is no single method of modeling a system. Each modeler eventually develops his or her own methodology and standards depending on the application and practical issues.

In this reference we will attempt to give you a generic methodology which you can adapt to your own requirements and circumstances.

Even though several people may approach modeling differently and end up with different looking and structured models, all these models can work and give accurate diagnosis if modeled correctly. No one model is the only correct one.