Block Definition Diagrams (BDDs) (available in CORE Spectrum)

In SysML, blocks are generic units – systems, components, items, conceptual entities, and logical abstractions. Block definition diagrams (BDDs) are used to define blocks in terms of their structure, their classification, and their behavior. The BDDs are available for elements in the Component class (as well as any other subclasses of ImplementationUnit).

When put into practice and mapped to our STRATA methodology, blocks are used to represent implementation units (hardware, software, and people). Block definition diagrams are used to define the composition and the classification of implementation units. Given this split usage, CORE implements two distinct flavors of the BDD:

• Structure Block Definition Diagram - the structure / composition of an implementation unit. This is similar to a traditional physical hierarchy with select semantic and representational differences.

• Classification Block Definition Diagram - the classification structure (superclasses and subclasses) of a model. This is the systems variant of the UML class diagram. Rather than representing the structure of an implementation unit, it represents the inheritance tree (for example, TransportationEntities is a generalization of Planes, Trains, and Automobiles).