Broadcast date: December 8th, 2021
Welcome! Behind the eighth door of our MBSE Podcast Advent Calendar, we take a look at the domain knowledge model.
For the object flows in the use case activities, we have defined the types of flowing objects. These are mostly blocks and value types of the domain knowledge model. Or put in another way, the domain knowledge model defines the types of objects that the system uses in its functions. Let’s look at it in the model and again at the use case activity “Enjoy Christmas tree”.
There are only a few object types like “SI_Power”, “Hi_Light”, and “FlashingProgram”. The prefix “SI” indicates that it is an object type that occurs in a system interface to another system, and the prefix “HI” indicates that it is an object type that occurs in a system interface to a human.
These types are defined besides others in the domain knowledge model, which is partially depicted in the following block definition diagram:
The value type “cm” is a specialization of the primitive type Integer from the SysML library. It is our decision that we take integer values for cm. An alternative would be real. SysML also explicitly supports the modeling of units. However, we did not use that for simplicity. Of course, all these types are good candidates for a model library.
The domain knowledge represents the knowledge of your system. If you ask your system: “Do you know the concept of FlashingProgram?”, it can answer yes. It knows it as defined in the domain block. If you ask the system about Christmas Gifts, it has no idea what it is.
So much for the eighth door of our MBSE Podcast Advent Calendar. We wish you a great 8th of December.