02: Overview of Package 'twin' and notations

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  • «twin»
  • «mappable»
  • «physical»
  • «process»
  • «sensor»
  • «actuator»
  • «digital»

Some special notations

CAVEAT: Some of these notational conventions may be subject to change!
The Webel Twin Pattern for SysML has some special notational conventions to support it: A «digital» entity element prefixed with an ‘@’ is a twinning entity or mapping entity. It maps (“twins”) a corresponding non-digital entity:
  • @Entity maps a real-world «physical» PhysicalEntity.
  • @Person maps a real-world «physical» Person (+ data).
  • @Place maps a real-world «mappable» Place (+ data).
  • @System maps a real-world «mappable» System.
Additionally:
  • Example: The block «twin» DigitalTwin has *person:@Person[0..*] and *system:@System[0..*] properties.
  • Compare: The same block «twin» DigitalTwin has a digitalEntity:@Entity[1] property (uses the verbose form for clarity for this special case)..

Dr Darren says:

I'm not 100% happy with that '*' prefix notation. The tool won't let one use '@' as a prefix in Property names, so this is a workaround. It is meant to be reminiscent of a "pointer".

The target of a «digital» DigitalEntity (a.k.a. @Entity) is always at least «mappable». Not every «mappable» element is «physical» (has mass). For example, a «process» Process is not «physical» but can still be mapped by a «digital» @Process entity.

By definition here a Place is «mappable» but not «physical» - because it is used here to reference place in a purely geometrical, geographical way. You can't "pick up a Place and feel how heavy it is". It may, however, refer to the spatial location of something «physical» that does have mass.

Last but not least, the following is a strict policy throughout the Webel Twin Pattern for SysML:

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