An extensible, ontology-based, distributed information system architecture

Abstract : The AFRL-sponsored Adaptive Sensor Fusion (ASF) program produced a software framework, the eXtensible Distributed Architecture (XDA), which facilitates the construction of scalable, flexible distributed systems. XDA is based on a simple ontology mechanism that enables the definition and maintenance of high-level object models to capture the shared semantics necessary for interoperability. This ontology based approach strikes a balance between having enough expressiveness to capture complex semantic interactions between components and being succinct enough for efficient, cross platform implementation. Shared object models can evolve and can be refined incrementally through standard, object oriented reuse mechanisms of inheritance and containment. XDA has been applied to sensor fusion and visualization. Additionally, XDA is being used to construct a database abstraction layer to access multiple, heterogeneous databases. xDA ontology objects can be persisted and can be retrieved with location transparency using an object-based query language. This capability allows objects residing in shared resources to be accessed uniformly by collaborating applications in a distributed environment. Keywords: Ontology, domain model, system evolution, distributed system.