Temporal Schema Versioning in tauOWL

The W3C OWL 2 recommendation defines the structure and data types for OWL documents, but lacks explicit support for time-varying OWL documents or for timevarying schema. In previous work, we introduced tauOWL which is an infrastructure and suite of tools to support the creation and validation of time-varying OWL documents, without requiring any changes to OWL 2. In this paper, we extend tauOWL to support versioning of the schema itself. To do so, we use a temporal schema which is an XML document that references the three components of a tauOWL schema: (i) an OWL 2 conventional schema, (ii) logical annotations which describe how an OWL 2 document can change over time, and (iii) physical annotations which describe where timestamps are placed. The support of schema versioning in the tauOWL framework means that conventional schemas as well as logical and physical annotations are versioned. More specifically, we propose two sets of primitives, one for the maintenance of conventional ontology schema and the other for updating temporal ontology schema, and define their operational semantics. We also illustrate their use, through an example.