Coordinated Adaptation for Adaptive Context-aware Applications

Efstratiou, Christos (2004) Coordinated Adaptation for Adaptive Context-aware Applications. Doctor of Philosophy (PhD) thesis, Lancaster University. (Full text available)

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Abstract

The ability to adapt to change is critical to both mobile and context-aware applications. This thesis argues that providing suf�cient support for adaptive context-aware applications requires support for coordinated adaptation. Speci�cally, the main argument of this thesis is that coordinated adaptation requires applications to delegate adaptation control to an entity that can receive state information from multiple applications and trigger adaptation in multiple applications. Furthermore, coordination requires support for recon�guration of the adaptive behaviour and user involvement. Failure to support coordinated adaptation is shown to lead to poor system and application performance and insuf�cient support for user requirements. An investigation of the existing state-of-the-art in the areas of adaptive and contextaware systems and an analysis of the limitations of existing systems leads to the establishment of a set of design requirements for the support of coordinated adaptation. Speci�cally, adaptation control should be decoupled from the mechanisms implementing the adaptive behaviour of the applications, applications should externalise both state i information and the adaptive mechanisms they support and the adaptation control mechanism should allow modi�cations without the need for re-implementation of either the application or the support platform. This thesis presents the design of a platform derived from the aforementioned requirements. This platform utilises a policy based mechanism for controlling adaptation. Based on the particular requirements of adaptive context-aware applications a new policy language is de�ned derived from Kowalsky's Event Calculus logic programming formalism. This policy language allows the speci�cation of policy rules where conditions are de�ned through the expression of temporal relationships between events and entities that represent duration (i.e. �uents). A prototype implementation of this design allowed the evaluation of the features offered by this platform. This evaluation reveals that the platform can support coordinated adaptation with acceptable performance cost.

Item Type:	Thesis (Doctor of Philosophy (PhD))
Subjects:	T Technology
Divisions:	Faculties > Sciences > School of Engineering and Digital Arts Faculties > Sciences > School of Engineering and Digital Arts > Digital Media
Depositing User:	Tina Thompson
Date Deposited:	07 Mar 2014 12:00 UTC
Last Modified:	07 Mar 2014 12:00 UTC
Resource URI:	https://kar.kent.ac.uk/id/eprint/38644 (The current URI for this page, for reference purposes)