1. Upper Ontology Summit March 14, 2006 Michael Gruninger Semantic Technologies Laboratory University of Toronto

2. Goals Develop methods to relate the existing upper ontologies to each other. Create a common subset ontology that is compatible with all of the linked upper ontologies.

3. Relationships among Ontologies Theory T 1 generalizes theory T 2 if and only if T 1 is definably interpretable in a theory T 3 and T 2 is a consistent extension of T 3. Problem: Given two theories T 1 and T 2, determine whether there exists a nontrivial theory that generalizes both.

4. Requirements What do we need so that we can prove that one ontology is a generalization of another? –the ontology must consist of a consistent set of axioms –the ontology must axiomatize its intended models Evaluation of the relationships between ontologies is made using their axioms alone; it cannot rely on intended models of concepts that are not axiomatized. If the axioms of an ontology are insufficient to capture their users' intended semantics, then there is little progress that can be made towards integration

5. Process Specification Language PSL (ISO 18629) is a modular, extensible ontology capturing concepts required for process specification There are currently 300 concepts across 50 extensions of a common core theory (PSL-Core), each with a set of first-order axioms written using Common Logic (ISO 24707). Two kinds of extensions: Core theories Definitional extensions

6. Modularity and PSL PSL-Core SubactivityOccurrence Trees Atomic ActivitiesDiscrete States Complex Activities Activity Occurrences