Real time summarization and visualization of ontology change in Protégé

Property restrictions play an important definitional role in an ontology. The correct introduction and inheritance of restrictions is important for ensuring the correct modeling of a domain. Many ontologies have large, complex class hierarchies, and many classes are defined with restrictions. When editing such an ontology, it is often difficult to determine the global impact of a local change. For example, removing a subclass link (axiom) can result in the unintentional loss of inherited restrictions over many levels. In this paper, we introduce a dynamic summarization and visualization methodology, called a Live Difference Taxonomy (LDT), to succinctly display a summary of the effects of changes to the ontology. LDTs are created on-the-fly as the ontology is edited, allowing an ontology developer to view the overall impact of their changes in a compact, visual display. We introduce an open-source plugin for the Protégé ontology editor that implements LDTs. It lets the users choose from several kinds of LDT summaries and lets them control the degree of summarization. The LDT Plugin supports heuristics-based alerts that inform the user of changes to sets of classes that are modeled with the same types of restrictions.