Ontology-based faithfully formalizing activities and reasoning for context-awareness

Respecting an interactive context involving multiple participants, dynamic characteristics of their activities will cause situations not faithfully described in a static method. In particular, the goal that represents the meanings of activities (equally as changes on situations), is far beyond the scope of ontology languages, such as the OWL. Then, we formalize activities as a sequence of context changes for computing entities. Further, the Past-Linear Temporal Logic(Past-LTL) is proposed to formulate the temporal relationship within activities and complement reasoning for context. In addition, we reduce the validation of OWL-based temporal formulae into checking the entailment in OWL.