Broadcast date: December 7th, 2021
Welcome to the 7th door of our MBSE Podcast Advent Calendar. Behind the door, we take a look at the system use case activities.
Behind each of our use cases, we define an activity to model the functional decomposition including control and object flows. Let’s look at it in our model.
In the containment tree, you can see that the activity is owned by the use case.
The activity diagram shows the execution order of actions.
We’ve modeled each action as a call behavior action, which means each step of the Christmas tree installation is detailed and defined by an activity. This defines the entire system behavior of the use cases with activities, which has many advantages, e.g., it is a prerequisite for the FAS method for deriving functional architectures, which we will look at another day.
Another special feature in our modeling is the separation of the functions responsible for input and output functionality from and to the actors and the other functions. We have modeled this with activity partitions. This is analytically useful and also good preliminary work for the FAS method. The stereotype “IO” comes from the profile for the FAS method.
The outgoing transportation net parameter of the activity on the left side is a so-called streaming parameter, which means the object can flow out of the activity during the execution.
The input parameter transportation package flows into a datastore node to make the object available several times for different actions.
Finally, we show another example from our MBSE Podcast Christmas Tree: the continuous use case “Enjoy Christmas tree”. Continuous use cases represent a continuous behavior.
The “Flash lights” activity runs continuously until the tree is turned off. That behavior is modeled in the state machine that we will present another day.
So much for the seventh door of our MBSE Podcast Advent Calendar. We wish you a great 7th of December.