Capella Operational Analysis practical example

The steps and diagrams will be created in the same order as described in the MBSE with Arcadia method step-by-step for Operational Analysis, and captured again below:

Capture Operational Entities and Actors

As captured in the Operational analysis activities matrix, first needs to be created an Operational Entity Breakdown diagram (OEBD). New diagrams can be created from the Capella Activity Explorer; however, we will use the project explorer to create a new diagram under the package Operational Entities.

To create a new Operational Entity Breakdown diagram, select from the project explorer “Operational Entities”, then mouse right-click “New Diagram / Table…” > “Operational Entity Breakdown”, as below:

When the Operational Entity Breakdown window is open, a new name can be given to the diagram. It was chosen not to change the diagram name, as below:

With the [OEBD] open, select first from the Palette the correspondent model element and then click on the diagram to create the Operational Entity OE 1, Operational Actor OA 2 and OA 3, as below:

 Let’s rename the model elements created. To open the model element Property window, double click on an element, for example Operational Entity (OE 1) and rename to Operational Users, as below:

Repeat step above to rename Operational Actors (OA 2 and OA 3), as below:

 

Capture Operational Capabilities

The Operational Capabilities diagram will be created next and not renamed.

From Project Explorer, select Operational Capabilities package, then mouse right-click “New Diagram / Table” > “Operational Capabilities Blank”, as below:

Keep the same name as default: [OCB] Operational Capabilities

From the Palette, to show Operational Actor Cabin Crew, select “Operational Actors”, then click on a blank area of the diagram to open the Transfer Dialog, as below:

In the Palette, select “Operational Capability”, and click on a diagram blank area to create the Operational Capability 1.

From the Palette, select “Involvement”, then click on the previously created Operational Capability 1 in the diagram, then click on the “Cabin Crew” Operational Actor to create an involvement link between the two, as below:

Double click on the Operational Capability and rename it to: Perform Flight On-Board Announcements:

The Operational Capability diagram showing the model elements relevant to this view:

Define Operational Activities

This section will describe how to capture Operational Activities with the Operational ActivityBreakdown Diagram.

A new Operational Activity Breakdown Diagram (OABD) can be created from the project explorer and under an Operational Activity. To create an OABD, select “Root Operational Activity”, then click “New Diagram / Table…” > “Operational Activity Breakdown”, as below:

Create Operational Activity Breakdown Diagram

When the “New Operational Activity Breakdown” window opens, rename the diagram to: In-flight Operational Activity:

From the Palette create three Operational Activities in the diagram:

  • Broadcast Movies.
  • Watch Movie.
  • Play Imposed Movie.

Define Operational Activities Interactions

Next step will be to create Operational Activities Interactions Blank (OAIB) diagram, where Operations Activities can be captured. OAIB diagrams can be created under:

  • An Operational Activity.
  • Operational Capability (OC). When created under the OC model element, activities are related and describe the Operational Capability.

For this example, an OAIB will be created under the Operational Capability that describes it. To create a new OAIB, select Perform Flight On-Board Announcements Operational Capability, then mouse right-click “New Diagram / Table…” > “Operational Activity Interaction Blank”:

Keep the same diagram default name: [OAIB] Perform On-Board Announcements.

When the OAIB diagram is created,  select “Operational Activities” from the Palette and then click on the blank area of the diagram to show the Transfer dialog window. In the Transfer dialog window select all three Operational Activities and then “Add All Elements” to add only the three Operational Activities, then click “Ok” to close window:

Reorganise the Operational Activities and create the first Operational Interaction. To create the Operational Interaction, select in the Palette “Interaction”, then click on the “Play Imposed Movie” then on “Broadcast Movies” Operational Activities, as below:

Repeat the process above and create a new Interaction between Broadcast Movies and Watch Movie.

Next let’s change the Interaction name. To rename the Interaction 1, double click on the “Interaction 1”. When the Properties window opens, rename interaction to Safety Instructions. Repeat the rename process for Interaction 2. When completed the OAIB diagram should be as below:

Allocate Operational Activities

Operational Activities should be allocated to Operational Entities or Actors that are responsible to execute them. For this it will be created an Operational Architecture Blank (OAB) diagram where it will be shown Operational Entities and Actors and allocated Operational Activities.

To create an Operational Architecture Blank diagram, select “Operational Entities” in the Project Explorer, then mouse right-click “New Diagram / Table…” > “Operational Architecture Blank”, as below:

When the New Operational Architecture Blank window shows, leave the name as default: [OAB] Operational Entities and click “Ok”.

Let’s insert Operational Entities and Actors to the diagram. To insert Operational Entities to the OAB diagram, select in the Palette “Operational Entities”, then click on a blank area of the OAB diagram, then “Add all Elements” > “Ok”, as bellow:

To insert Operational Actors, click on the arrow next to Operational Entities to show Operational Actors in the Palette. In the transfer dialogue click on “Add all elements” > “Ok”:

When Operational Entities and Actors are inserted into the Operational Architecture Blank diagram, it should be shown as below:

To allocate Operational Activities to Operational Entities and Actors select “Manage Activity Allocation” then click on the Passenger Operational Activity shown in the diagram, as below:

When the transfer dialogue opens, select “Play Imposed Movie”, then “Add selected element(s)” > ”Ok”:

Repeat the process above to Manage Activity Allocation for Passenger and Aircraft as below:

Interactions are also added to the diagram as they were previously defined in the OAIB diagram in the previous step. The OAB diagram can be a good diagram candidate to not only Manage Activity Allocation, but also define new Interactions now in context with structure (i.e., Operational Entities and Actors) and behaviour (i.e., Operational Activity).

Describe Operational Capabilities with Operational Process

Perform Flight On-Board Announcements Operational Capability was previously described by the relevant Operational Activities captured in the OAIB diagram under the Operational Capability. Operational Capabilities can also be described with Operational Process. Operational Process references what Operational Activities and Interactions are considered relevant to describe an Operational Capability, but also to show in diagrams the flow of Activities and Interactions.

An Operational Process could be created from this diagram; however, it will be created from the OAIB diagram instead. As the OAIB diagram is defined under the Operational Capability, any Operational Process created will also be created under the same Operational Capability promoting consistency.

To create an Operational Process, Hold Ctrl, then select all three Operational Activities and the two Interactions, then mouse right-click on a model element (e.g., Watch Movie) > “Operational Process” > “Create an Operational Process”, as below:

Rename the new Operational Process to Play Imposed Video as below:

The Play Imposed Video Operational Process defined in the Operational Architecture Interaction Blank diagram should look as below:

To create an Operational Process Description (OPD), select “Perform Imposed Video” Operational Process from the Project Explorer, then mouse right-click “New Diagram / Table…” > “Operational Process Description”, as below:

When the New Operational Process Description window shows, do not rename the diagram and confirm the default name provided as [OPD] Play Imposed Video and click “Ok”.

The below Operational Process Diagram is automatically created showing the three Operational Activities referenced by the Operational Process:

An Operational Process can also be shown in the Operational Architecture Blank diagram. Inserting an Operational Process in a diagram not only shows the flow of Operational Activities and Interactions, but also what Operational Entities and Actors are involved in a diagram. If more Operational Processes were defined a combination of insert/remove can be performed to help the analysis process.

To insert an Operational Process in the Operational Architecture Blank diagram, in the Palette select “Operational Process”, then click on a blank area of the diagram. The Transfer dialogue window will be shown, then click “Add selected elements(s)” > “Ok”, as below:

Describe Operational Capabilities with Operational Activity and Entity Scenarios

Operational Capabilities can be described by Operational Process that describes and involves Operational Activities and Interactions above but can also be described by Operational Activity and Entity Scenarios.

To create new Operational Activity Scenarios, select from the Project Explorer the “Perform Flight On-Board Announcements” Operational Capability, then mouse right-click “New Diagram / Table…” > “Activity Scenario”, as below:

When the New Activity Scenario is shown, keep the default name and click “Ok”.

It is created a new Operational Activity Scenario diagram under the Operational Capability, as below:

To add Operational Activities to the diagram, select Activities in the Palette, then when the Transfer Dialogue window opens select the three Operational Activities, then click “Add selected element(s)” > “Ok”. By selecting the three Operational Activities will not add the Root Operational Activity to the diagram.

Resize Operational Activities to show full name in diagram and reorder them. Operational Activity Scenario should be as below:

To add Interaction to the Operational Activity Scenario, select “Interaction” from the Palette, then click first on the Play Imposed Movie Operational Activity’ lifeline and then on the Broadcast Movies Operational Activity lifeline, as below:

When the Selection Dialog window opens, select “Safety Instructions [Play Imposed Movie -> Broadcast Movies]”, then “Ok”:

Repeat the process above for the other Interaction between Broadcast Movies and Watch Movie and add “Imposed Movies [Broadcast -> Watch Movie]”.

When completed the Operational Activity should be like as below:

An Operational Entity Scenario can also be chosen to describe an Operational Capability.

To create an Operational Entity Scenario, the steps are like above described for Operational Activity Scenario. Select Perform Flight On-Board Announcements Operational Capability from Project Explorer, then mouse right-click “New Diagram / Table…” > “Entity Scenario”, as below:

Keep the same diagram default name: [OES] Perform On-Board Announcements.

Select “Operational Entities / Actors” and “Interaction” from the Palette. When completed the diagram should be as below:

The above steps allow to create new Operational Activities and Entity Scenarios under an Operational Capability.

As the Play Imposed Video Operational Process is created, Capella does provide the capability to transition and initialise Operational Activities and Entity Scenarios, to represent time-ordered scenarios.

To create a new Operational Activity Scenario from an Operational Process, open the Operational Architecture Blank diagram, then mouse right-click on the “Play Imposed Video” Operational Process, then “Transitions” > “Operational Process to Operational Activity Scenario Initialization”, as below:

Transitions can also be done by selecting the “Play Imposed Video” Operational Process from the Project Explorer and then follow the same steps as described above.

Capella creates a new Play Imposed Video 3 Operational Activity Scenario under the Perform Flight On-Board Announcements Operational Capability, as below:

The number 3 in the name represents the third scenario created under the Operational Scenario. 

Now let’s create the Operational Activity Scenario to show model elements in a diagram.

To create Operational Activity Scenario, select Play Imposed Video 3 Operational Activity, then click “New Diagram / Table…” > “Activity Scenario”, as below:

The new Operational Activity Scenario created may need to be rearranged to show the same as the All Interaction inserted in Operational Activity Scenario described above.

To create a transition for the Operational Entity Scenario, select “Play Imposed Video 3” Operational Activity from the Project Explorer, then click “Transitions” > “Operational Activity Scenario to Operational Entity Scenario Initialization”, as below:

An Operational Entity Scenario can be created similarly to described for Operational Activity Scenario above, select “Play Imposed Video 3 (OES) in the Project Explorer, then mouse right-click “New Diagram / Table…” > “Entity Scenario”, as below:

When the New Entity Scenario window is shown, keep the same diagram as proposed: [OES] [OAS] Play Imposed Video 3 (OES).

A new diagram is created and visible in the Project Explorer: [OES] [OAS] Play Imposed Video 3 (OES) and the new Operational Entity Scenario diagram is open. The diagram model elements and display should be similar to the Operational Entity Scenario described above.

There is freedom in Capella to create the diagrams in any sequence.

Despite elements in Scenarios represent only references to model element, this means Scenarios are not synched with the model evolution, hence, consistency and completeness needs to be checked. Links created during the transition helps to verify consistency, correctness, and completeness of diagrams in a model.

For this simple example, Operational Activity and Entity Scenarios diagrams do share the same model elements and Operational Capability description. The reason was to describe the option to create Scenarios from an Operational Process using the Capella Transition capability.

Hence, the below will be performed in the model:

  • Delete the Perform On-Board Announcements Operational Activity Scenario.
  • Delete the Perform Flight On-Board Announcements Operational Entity Scenario.
  • Rename both Scenario and diagram for Play Imposed Video 3 Operational Activity Scenario to Play Imposed Video.
  • Rename Play both Scenario and diagram for Imposed Video 3 (OES) Operational Entity Scenario to Play Imposed Video. It could be left (OES) to visualise the Scenario was transitioned.

The Operational Analysis project explorer at this point should look as below:

Operational Analysis traceability flow

When completed the model for Operational Analysis Project Explorer should look like as below:

As described in sections above, the Capella tool implements the Arcadia method, and the Arcadia method owns an ontology. Arcadia ontology defines model elements and the relationship among them enabling inherent traceability. Hence, it is possible in Capella to query and navigate from one model element to another.

For this example and only for the Operational Analysis (similar analysis can be done for all the other layers), it will be described as an example of how model elements are related via their relationship and navigate from one to another model element using a combination of Project Explorer and the Semantic Browser.

Starting with the Project Explorer. The steps for the model elements navigation are captured in the figure above (yellow) and again below:

  • (start) Perform Flight-Onboard Announcements Operational Capability.
  • Play Imposed Video Operational Process.
  • Watch Movie Operational Activity.
  • (end) Passenger Operational Entity.

In the Project Explorer select the Perform Flight On-Board Announcements Operational Capability. The Operational Capability will be shown in the Semantic Browser under the current element area. Under the Referenced Elements area it can be seen the Play Imposed Video Operational Process. Select and press F8. This Capella command will navigate back Project Explorer and to the Play Imposed Video Operational Process model element.

To navigate from Play Imposed Operational Process to Watch Movie Operational Activity, select first the “Play Imposed Video” Operational Process in the Project Explorer then in the Semantic Browser, select “Watch Movie” Operational Activity and press F8 to navigate to model element as below:

Finally, let’s navigate from Watch Movie Operational Activity to Passenger Operational Actor.

Select “Watch Video” Operational Activity from the Project Explorer, then under Referencing Elements select “Passenger” and click F8 to navigate to model element in Project Explorer, as below:

Capella creates links between model elements that are going to be explored hereafter. 

By default, let’s make sure links will be visible. Click on “View Menu” > “Filters and Customisation”, as below:

When the Filters and Customisation window opens locate the following filters:

  • Functional Chains involvements
  • Trace

Let’s make sure the filters are not set. An example for Trace filter bellow:

Figure below, shows relevant links that allow the same navigation between model elements as described above using the semantic browser and the relationship between model elements. Links are captured and can be seen in the Project Explorer highlighted in blue in figure above.

When completed the analysis above, let’s set the filters Set Default Filters. Click on “View Menu” > then “Set Default Filters”.

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