Semantic Interoperability Integrating and Augmenting Legacy Applications with OWL Ontologies

This paper describes an approach to software interoperability based on knowledge representation technologies developed in support of the emerging semantic Web. In particular, we are interested in the interoperation of an arbitrary set (two or more) of "legacy" applications that operate in a common domain, but that were not originally designed to support each other or to share information. To do this, we develop a means to create a general meta-model of the common domain of discourse that contains, organizes and correlates the essential information that each of the applications needs to function as well as any additional information particular to the composed system. This model becomes the basis of communications between the cooperating systems. Each legacy application is able to obtain input data from the model and export output information to augment or update the model in a form that allows cooperating systems to operate on the updated information. We represent the meta-model in RDF/XML which, we believe, provides several important advantages. RDF is a knowledge representation language that allows information to be described as a set of factual sentences. When these sentences are constrained by and consistent with an OWL ontology, this enables the use of an existing, robust collection of automatic reasoners and other logical tools to classify, evaluate, query, apply rules and otherwise operate on the model itself, independently of the cooperating applications. We describe a "layered" set of OWL ontologies that serve as domain models for a number of legacy operations analysis simulations, aeronautical engineering design tools and software prototypes that are used to support the integrated design and development of aeronautical systems. We describe an approach to the development of the ontologies that references, and imports concepts from well known foundational ontologies, including DOLCE, GML and PSL. We then describe an example that illustrates a methodology for creating the meta-model as an "operational scenario" that indicates the benefits to interoperability of this approach. Finally we discuss the use of SPARQL queries and SWRL rules that effectively expands the functionality of the system and greatly improves the analysis of the output of the system of cooperating simulations and tools.