Context-aware service selection using graph matching

The current evolution of Ubiquitous Computing and of ServiceOriented Computing is leading to the development of context-aware services. Context-aware services are services whose description is enriched with context information related to the service execution environment, adaptation capabilities, etc. This information is often used for discovery and adaptation purposes. However, context information is naturally dynamic and incomplete, which represents an important issue when comparing service description and user requirements. Actually, uncertainty of context information may lead to inexact matching between provided and required service capabilities, and consequently to the non-selection of services. In order to handle incomplete context information, we propose in this paper a graph-based algorithm for matching contextual service descriptions using similarity measures, allowing inexact matches. Service description and requirements are compared using two kinds of similarity measures: local measures, which compare individually required and provided properties (represented as graph nodes), and global measures, which take into account the context description as a whole, by comparing two graphs corresponding to two context descriptions.