Figure D.5 - Establishing Top Level Use Cases for the Hybrid SUV

Gallery
Tutorial
TRAIL: The SysML-1.6 Hybrid SUV sample and specification diagrams in MagicDraw/Cameo (with annotations) [UNDERGOING UPDATE to SysML1.7]
Section
Section: SysML-1.6: HSUV sample
UML keywords
UseCase Diagram
UseCase
UseCase::subject
Actor
Association
SysML keywords
«system»
HSUV sample problem
Slide kind
SysML UseCase Diagram
Webel: MBSE: SysMLv1: Prefer a custom «actor» extension of a Block (such as the non-normative External) over UML-style Actor for use as parts in IBDs and on allocation swimlanes. You can also have a Trace from a block-based «actor» to a UML-style Actor.
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Additional to the spec figure, a non-normative «system» block has been used as the 'subject'.
Up next
Figure D.6 - Establishing Operational Use Cases for Drive the Vehicle
Notes
[CAPABILITY, DISPLAY, STYLE] In MagicDraw/Cameo the name and any stereotype keywords of a Classifier subject of a UseCase may be shown in the top-middle (not just top-left)
[GOTCHA, TOOL, WARNING] Webel: SysMLv1/UML: MagicDraw/Cameo: AVOID the the vendor-specific «useCaseModel» stereotype for Model packages, it leads to confusion with the rectangular 'subject' notation
[CONVENTION, MODELLING, TIP]{RECOMMENDED} Webel: MBSE: SysMLv1: Prefer a custom «actor» extension of a Block (such as the non-normative External) over UML-style Actor for use as parts in IBDs and on allocation swimlanes. You can also have a Trace from a block-based «actor» to a UML-style Actor.
Snippets (quotes/extracts)
  [SysML-1.6] The use case diagram for “Drive Vehicle” in Figure D.5 depicts the drive vehicle usage of the vehicle system. The subject (HybridSUV) and the actors (Driver, Registered Owner, Maintainer, Insurance Company, DMV) interact to realize the use case.
  [UML-2.5.1] A UseCase specifies a set of actions performed by its subjects, which yields an observable result that is of value for one or more Actors or other stakeholders of each subject.
  [UML-2.5.1] UseCase::subject : Classifier [0..*] ... The subjects to which this UseCase applies. Each subject or its parts realize all the UseCases that apply to it.
  [SysML-1.6] The «system» and «external» stereotypes are user defined, not specified in SysML, but help the modeler to identify the system of interest relative to its environment.
  [UML-2.5.1] A subject for a set of UseCases (sometimes called a system boundary) may be shown as a rectangle with its name in the top-left corner, with the UseCase ellipses visually located inside this rectangle.
  [UML-2.5.1] Where a subject is a Classifier with a standard stereotype, the keyword for the stereotype shall be shown in guillemets above the name of the subject.
Visit also
Visit also (backlinks)
Webel: SysMLv1: Overview of annotated Diagram Slides and Note pages related to UseCases and their combination with a System (of interest), SystemContext, and drill-down to scenario Sequence Diagrams (Interactions) and Activity Diagrams.
SysMLv1: A common misunderstanding: Just because a UseCase symbol appears inside the rectangle of a subject Classifier does NOT mean that it is owned by that Classifier and can only have that one Classifier as 'subject', and it does not imply ownership!
SysMLv1: "Should" the 'subject' of a top-level UseCase be a System or (a particular) SystemContext? Answer: Which one would you like to be correct!? [WITH EXTERNAL LINKS]
SysMLv1: MagicDraw/Cameo: Having a SystemContext as the 'subject' of each main UseCase plays nicely with the feature for automated creation of usage-level allocation swimlanes in SysML Activity Diagrams for part properties. But it's not the only way.
SysMLv1: MagicDraw/Cameo: INTRINSIC GOTCHA: Care must be taken with ownership of Activities used as UseCase scenarios vs the ‘subject’ of the UseCase. Make sure you don’t get an Activity ‘context’ mismatch! It's up to you to manage it as intended.
SysMLv1: MagicDraw/Cameo: Automated creation of usage-level allocation swimlanes in SysML Activity Diagrams for part properties of a Block. EXAMPLE: A UseCase scenario within a SystemContext as UseCase ‘subject’.
SysML/MBSE: Many videos, tutorial slides, and guides to MBSE with SysML present particular modelling recipes as though they are THE way to do something in SysML, not just ONE way of doing it in SysML. They are not necessarily enforced by the SysML spec.
SysMLv1: UseCase scenario representations: On use of Activity Diagrams with swimlanes and/or Sequence Diagrams (Interactions): Actor or block-based custom «actor» on 1st (typically left) Lifeline/Swimlane, System/Subsystem on 2nd Lifeline/Swimlane
Webel: MBSE: SysMLv1: Prefer a custom «actor» extension of a Block (such as the non-normative External) over UML-style Actor for use as parts in IBDs and on allocation swimlanes. You can also have a Trace from a block-based «actor» to a UML-style Actor.
Webel: SysML for MBSE: The frequent recommendation that each UseCase have at least one "primary" scenario is a very useful and highly recommended CONVENTION (only). But it is not actually enforced by the SysML1.7 or UML2.5.1 metamodels or specifications.
SysML/MBSE: Cameo/MagicDraw: MagicGrid® and the MagicGrid® Book of Knowledge: A pragmatic review of some selected aspects by Dr Darren of Webel IT Australia
Related slides (includes other tutorials)
Related slides (backlinks, includes other tutorials)
UseCases - UML subject vs SysML Block
Package, Model, or SysML Block as UseCase owner