Modeling ontology evolution via Pi-Calculus

• We provide a new angle to model the operational semantics of the changes in ontology evolution.
• The entities in the ontology is model as initiative agents that interact with each other with state transitions during the change.
• We use Pi-Calculus to clarify the operation semantics of the changes.
• The Mobile Work Bench is used as a tool to verify the applicability of our method.

Extending and updating real world ontologies is unavoidable challenging with our ever-evolving understanding of the world and the evolution of the world by itself. In the current researches, changes are usually modeled as passive instant results of operations such as to add a child class or to delete a property, executed by the administrators. But this view neglects the real world facts that (1) an ontology evolves continuously over time, not just hopping instantly between static versions; (2) a change is a coherent procedure although it may be separated from the administrative point of view into different phases, such as to request, detect, represent, evaluate, implement and propagate the change. This paper provides an inside perspective of the ontology itself to model its evolution. The ontology entities are regarded as autonomous agents with find-grained state specifications. The operational semantics of the changes are formalized as series of information exchange actions of the agents. Pi-Calculus serves to describe the operational semantics in our modeling. Firstly, an ontology is encoded into a hyper graph. Then the nodes and edges in the hyper graph are formalized as Pi-Calculus processes. The replication operator is used to add new entities to the ontology and the communication rule works for the resolution of the information exchanges. Thus, a change is modeled as a coherent procedure as clarified in its operational semantics. A case study shows the feasibility of our method on the Mobility Workbench (MWB). We believe that the operational semantics in our scenario disclose the autonomous evolving nature of ontology evolution.