Context self-construction algorithm in context-aware computing framework

Owing to context absent, a context-aware computing service would be interrupted in ubiquitous computing system. A context retrieval algorithm was proposed to rebuild the missing context. A context graph at the fallen time was created based on context ontology, and then a spreading activation process was applied to the graph to find paths link to the missing context. Weights of the paths were calculated so that most suited path can be choused. The algorithm was implemented in a ubiquitous computing framework, and was applied in a tourist guiding system.