Strategies for On-The-Fly Composition of Context Information Services

Context-aware services adapt to ever-changing environments and therefore face the challenge to acquire context information in a priori unknown situations. They rely on other services (e.g. for context acquisition) and failures of these services may occur. In this paper we introduce concepts for the CoCo Infrastructure in order to deal with services that fail to deliver requested context information. The abbreviation CoCo stands for ”Context Composition” and is a service-oriented infrastructure supporting context-aware services that is currently developed by the MNM-Team. This composition of context information services often has to be carried out dynamically at run-time as it depends on the user’s context which services can be used. We show how static instructions and dynamic methods can be combined to find a tradeoff between the level of sophistication and necessary resources, such as e.g. computing time.