Reasoning about uncertain contexts in pervasive computing environments

A prototype pervasive computing infrastructure, Gaia, which allows applications and services to reason about uncertainty, using an uncertainty model, is described. The model is based on a predicate representation of contexts and associated confidence values, and uses mechanisms like probabilistic logic, fuzzy logic, and Bayesian networks. Gaia's context infrastructure provides services and libraries that help entities acquire and reason about uncertain contextual information. Access control decisions in Gaia use fuzzy reasoning, and Bayesian network is used for troubleshooting the environment.