The last invited talk / short course of the summer school was Michael Grüninger‘s “Process Ontologies in Action: From Applications to Foundations”. He occupied the two slots of Friday afternoon.
Michael focused his course on how to build ontologies to describe processes, motivated by the fact that everything we do is a process. In particular, the focus is on the Process Specification Language (PSL) Ontology.
First of all, he presented his methodological presuppositions, namely: ontologies are axiomatized in some logic; ontologies are designed with a set of requirements in mind; therefore: ontological commitments are specified as semantic requirements, which are formalized in models in the logic. PSL is formalized in First-Order Logic (FOL).
As motivation and illustration, Michael showed many situations that could be viewed as processes: movies, day-to-day activities like washing hands, appliance maintenance instructions, construction, manufacturing, Semantic Web Services. For each scenario, he illustrated competency questions that might be used as requirements for ontologies that describe knowledge about these processes.
He then presented the basic concepts of PSL — activities, activity occurrences, time-points and objects — and the ontological commitments of the language (e.g., time-points are linearly ordered, objects participate in activity occurrences at time-points, composition of complex activities, changes of state, etc.).
After the break, Michael quickly showed some of the axioms of PSL in Common Logics Interchange Format (CLIF, a successor of KIF — Knowledge Interchange Format) and switched to a visual notation for the core concepts and commitments of PSL. There are models for representing occurrence structure, sub-activity composition, occurrence/activity trees and so on.
Next, an exercise for modeling one of four possible scenarios (a party, cooking feijoada, a soccer match, the schedule of the Summer School) was conducted in groups, followed by a discussion on people’s experiences.
His slides were made available at the summer school’s website.