Item definition is based on SysML diagrams like Block Definition Diagrams (BDD), Internal Block Diagrams (IBD) or SOX Concept Diagrams (SCD). To learn how to model system architecture and safety or security items using SysML diagrams, please visit page System Design.
For example, a security item may be represented by a BDD and an IBD as shown in the following pictures based on ISO/SAE 21434 annex H headlamp example. The SysML BDD depicts the composition hierarchy of the operational environment including the item, i.e., the head lamp system, whereas the IBD emphasizes the internal structure and how parts are connected.
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