Toward Dynamic Adoption for a User's Situation Information in a Context-Aware Workflow System

Recently, there are many studies to adopt the workflow model, which has been successively applied to traditional computing environments, into ubiquitous computing environments for context-aware and autonomous services. A service in the ubiquitous computing environments must be executed according to a user’s situation information, which is generated dynamically from sensors. However, such existing workflow systems as FollowMe and uFlow to support context-aware services through workflow models, can’t immediately adopt changes of a user’s situation into a already on-going service workflow. In this paper, we propose a context-aware workflow system, for ubiquitous computing environments, which can apply changes of user’s service demand or situation information into an on-going workflow without breaking its operation. To do this, the proposed system represents contexts described in a workflow as a RDF-based DItree (Document Instance tree). The system uses the tree information to recognize a exact position to be changed in the on-going workflow for user’s situation changes, and to reconstruct only the position under the influence of the changes in the DItree. Therefore, the suggested system can quickly and efficiently apply a change of user’s new situation into a on-going workflow without a lot loss of the time and the space, and can offer a context-aware service continuously, according to a new workflow.