There is growing appreciation of the importance of ideas related to context-aware software, situated computing, and situational awareness. Attempts to use software to determine the situation of current interest to a user face ambiguity.

The authors report on an addition to their previously described application framework, to provide a place in the framework for components that use mediation to resolve ambiguity in the interpretation of sensed context, either by interaction with the user or automatically. Four guidelines for designing mediation are offered; mechanisms for handling seven challenges of mediation are described.

Specialists may find this incremental contribution of interest. Readers who want to study the area will find the list of related work in Table 1 and the references useful. There is little here for the general reader interested in situational software.