SYSML

This SysML diagram example was redesigned from Wikimedia Commons file: Use case restaurant model.svg.
"Use case model of a restaurant business." [commons.wikimedia.org/ wiki/ File:Use_ case_ restaurant_ model.svg]
"The use case diagram describes the usage of a system (subject) by its actors (environment) to achieve a goal, that is
realized by the subject providing a set of services to selected actors. The use case can also be viewed as functionality and/
or capabilities that are accomplished through the interaction between the subject and its actors. Use case diagrams include the use case and actors and the associated communications between them. Actors represent classifier roles that are external to the system that may correspond to users, systems, and or other environmental entities. They may interact either directly or indirectly with the system. The actors are often specialized to represent a taxonomy of user types or external systems." [omg.org/ spec/ SysML/ 1.3/ ]
The SysML diagram example "Use case restaurant model" was drawn using the ConceptDraw PRO diagramming and vector drawing software extended with the SysML solution from the Software Development area of ConceptDraw Solution Park.