MBSE with CORE 100821

Leveraging Use Cases: Key Aspects of the Metamodel

built from (built in)

Component

describes (described by)

involves (participates in)

extended by (extends)

includes (included in)

UseCase

elicits (elicited by)

elaborated by (elaborates)

Color Code

Requirement Element

Functional Element

refined by (refines)

decomposed by (decomposes)

Physical Element

Interface Element

Function

Requirement

Verification Element

Other Element

281

Defining SysML Use Cases

• Represent the highest level of abstraction for a system • Used to identify or discover requirements and system context • Describe a system’s requirement from an actor’s perspective (must provide observables to an actor) • Represents the interactions between the system and its external “actors” or components • Emphasizes functionality rather than control or timing—implicit is the discovery of functional requirements • Viewed by some as the easiest diagram to get wrong!*

* Holt and Perry, SysML for Systems Engineering, 2008, p. 154

282

MBSE with CORE