Priamos: a middleware architecture for real-time semantic annotation of context features

This paper proposes a middleware architecture for the automated, real-time, unsupervised annotation of low-level context features and their mapping to high-level semantics. The distinguishing characteristic of this architecture is that both low level components such as sensors, feature extraction algorithms and data sources, and high level components such as application-specific ontologies are pluggable to the middleware architecture thus facilitating application development and system configuration to different real-world scenarios. A prototype implementation based on semantic Web tools is presented in depth, while the benefits and drawbacks of this approach are underlined. We argue that the use of semantic Web provides powerful answers to context awareness challenges. Furthermore, it enables the composition of simple rules through human-centric interfaces, which may launch a context-aware system that will annotate content without the need for user technical expertise. A test case of system operation in a laboratory environment is presented. Emphasis is given, along with the theoretical justification, to practical issues that arise in real-world scenarios.