studentsupport@civilsystems.tu-berlin.de

The entire tutorial is available in pdf format, here: <<to add>>

//to add a short motivational intro about merging and aligning ontologies

Combining ontologies in Protégé

In order to combine ontologies in Protege, follow the next steps.

• Open Protégé
• Go to File → Open (or press CTRL + O) and select the first ontology you want to open

•  The ontology will appear as open on the drop down bar under the main menu

• Go again to File → Open (or press CTRL + O). On the dialog window which apper on the screen select yes. This means that the ontology will be open in the current session of the Protégé.

• Select the next ontology you want to open.
• In the drop down bar under the main menu you will have two ontologies loaded.

• Repeat the previous steps until you finish to open the ontologies you want to combine
• Once the ontologies are open, we are ready to combine/merge.Go to Refactor → Merge ontologies…

• Protégé offers a wizard to guide you step by step when merging ontologies. The first window of the wizard allows you to select the ontologies you want to merge together. Keep the CTRL key pressed and click on the ontologies you want to Join and click Continue button.

• Next view of the wizard allows you to select either you want to create a new ontology or to update an existing one. Select Merge into new ontology and click Continue button.

• Next view of the wizard allows you to define the IRI of the new ontology. Define the IRI and click Continue button.

• On the next view of the wizard, select the location on your computer where you want to save the ontology and click Continue button.

• On the next view select OWL/XLM Syntax and click Finish button.

Align the combined ontology in Protégé

The alignment of the ontologies on Protégé is a manual process which aim at the identification of the correspondences existing between the entities of two or more ontologies. To do this, the axioms we learned during the first assignment can be applied.

Re-organize the combined ontology in Protégé

Each ontologies was created following the reasoning line of its creator. This means that if two knowledge engineers are asked to independently represent theirs knowledge of the same domain, the ontologies created will not be identical as structure. Two knowledge engineers working together on creating an ontology must organize and re-organize their lines of reasoning in order to be able to take into account each others thoughts.

Extend the combined ontology in Protégé

Having two or more ontologies combined together, but without any overlap does not help too much. It is like having three strangers put together in an escape room without allowing any interaction. They will work individually by using theirs personal knowledge. But by allowing interaction they will make connections and will create an extended body of knowledge, ending up working as a team.

Extend the combined ontology by adding the missing pieces represented by classes, properties and data properties. Connect the individual ontologies in a such as way that you will have an interconnected system.