Failure Mode Dependency Models
A model for Diagnostics, Prognostics, Testability and Reliability

Areas of Applicability: (comparison chart)
 Diagnostics / Prognostics  System Engineering  Maintainability
 Testability  Reliability  Life Cycle Cost
 Design-for-Test  Safety  Other

What - Failure Mode Dependency Modeling is a dependency modeling approach that focuses purely on failure modes. By doing so, it can draw a high-level meaning from dependencies, whereas the dependency approach remains, like machine language, somewhat undecipherable.

Why - Failure Mode Dependency Models were established in an attempt to reduce the amount of data entry and to lessen the amount of abstraction of a simple dependency model. By focusing purely on failure modes, a Failure Mode Dependency Model can be made to correlate well with a reliability engineering process.

When - Failure Mode models are useful at describing models from which low-level diagnostic strategies can be created. However, the lack of Functional information precludes it from effective use for concept exploration, or higher-level strategies, where both functions and failure modes mix.

History - Failure Mode dependency models were formally first used as part of the WSTA program. This program was developed under Department of Defense funding as an approach utilizing the Dependency Model. As it used the same Dependency Modeling concept invented by Ralph De Paul, DSI International was subcontracted to assist in its development. Today, the program is considered obsolete, though attempts have been made to build additional products from its rather limited diagnostic approach.

Related Links - Functional Dependency ModelsHybrid Models