A Middleware Architecture Determining Application Context Using Shared Ontology

Context awareness is a key part of ubiquitous computing. Recent middleware supporting it have the architecture to provide a context model to represent context information. The middleware recognizes contexts by using sensed and inferred information, applies them appropriately. This implies that the middleware should be able to determine all contexts of applications running. But since context-aware applications will be applied to wider areas and their number increases, it has become difficult for the middleware to determine all contexts needed for various applications. To overcome this, we propose architecture providing context definition by application using shared ontology. The middleware makes and maintains the shared ontology base in a ubiquitous computing environment. Applications write the context decision rule describing their own context and register it to the middleware. Then the middleware generates context objects to make a context decision according to the registered rule. If the current situation satisfies the rule, the context object notifies context information to a relevant application. Our application-defined context is middleware-independent so that it can make ubiquitous computing applications more capable.