Contextualizing applications via semantic middleware

The use of description logics (DLs) in modeling various real-world domains, and reasoning about them, has well-known benefits. We believe that the same framework can be used for representing a user-centric view of usage contexts. A DL-reasoner can then be used for organizing context definitions, merging domain knowledge into these definitions, and performing recognition of contexts from sensor inputs. A pure DL-based approach, however, has certain limitations in a context environment; hence, a hybrid reasoning approach is proposed. To ensure syntactic and semantic interoperability, we adopt a semantic Web-compliant approach that uses the OWL-DL variant of the OWL Web ontology language. This allows us to aggregate various heterogeneous data sources, both directly in semantic Web formalisms, and indirectly via the use of a transformation framework capable of using data from legacy applications. Context and domain models, along with associated reasoners, are themselves context, user and/or organization-specific; hence multiple systems should be maintained and connected into a distributed architecture. In order to deploy this architecture in a mobile environment, an underlying SIP-based provisioning framework has been experimented with, enabling device, network and location transparency.