Design and implementation of a semantics-based contextual navigation guide for indoor environments

Location-based services have evolved significantly during the last few years and are reaching a maturity phase, relying primarily on the experience gained and the utilization of recent technologies, such as ontology-based modeling and rule-based reasoning. Ontologies are used to classify the terms used in a particular application, characterize possible relationships, and define possible constraints on using those relationships. Thus, they provide a suitable means for representing context models. The formal semantics of ontology-based approaches also enable simple reasoning tasks on the context information. Rule-based reasoning techniques are also used in order to offer extensive reasoning capabilities. Taking advantage of these opportunities, this paper presents C-NGINE, a Contextual Navigation Guide for Indoor Environments, strongly connected to the semantics behind user profile. Our approach, which focuses on indoor environments, uses OWL ontologies to capture and formally model profile and context information, and reasons on the ontology data using rules in order to support personalized context-aware navigation services. To test and demonstrate the approach, a prototype has been developed that documents the flexibility of the design.