IDEF
IDEF (Integration DEFinition) is a family of modeling languages in the field of Systems Engineering and Software Engineering. They cover a wide range of applications, from functional modeling, simulation, object-oriented analysis to design and acquisition of knowledge. These languages were developed with funding from the US Air Force. but they are in the public domain.
From the IDEF family the most widely recognized and used is the IDEF0, a functional modeling language developed in Structured Analysis and Design Technique (SADT).
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