Consistent Management of Context Information in Ubiquitous Systems

In context-aware systems, where the context information tends to be distributed and/or replicated, can be decisive to maintain the correctness of this information, owing to the decisions in context-aware systems are taken on the basis of it. In ubiquitous environments, new challenges are emerging, which can affect to the consistent management of the distributed context information. For instance, the dynamism is a feature that directly affects the availability of the resources deployed in the network, among other quality features, and it implies additional design and development efforts from software engineers. Service Oriented Architecture (SOA), together with replication techniques may help to improve resource availability and strengthen the system against node disconnections, nevertheless, additional techniques must be applied to ensure the consistency of the distributed/replicated resources. In this paper, an approach to support, from the software design stage, the synchronization and consistency management of context information is introduced. This approach follows the SOA model, and provides a common basis for the synchronization of distributed/replicated resources. A case study, related with an ubiquitous system deployed in a hospital where context-aware services can be found, will be described in order to show the feasibility of the proposal.