Patch panel: enabling control-flow interoperability in ubicomp environments

Ubiquitous computing environments accrete slowly over time rather than springing into existence all at once. Mechanisms are needed for incremental integration- the problem of how to incrementally add or modify behaviors in existing ubicomp environments. Examples include adding new input modalities and choreographing the behavior of existing independent applications. The iROS event heap, via its publish-subscribe coordination mechanism, provides the foundation for interoperation through event intermediation, but does not directly provide facilities for expressing these intermediations. The patch panel provides a general facility for retargeting event flow. Intermediations can be expressed as simple event translation mappings or as more complex finite-state machines. We describe an implemented prototype of the patch panel, including examples of its use drawn from real life applications in production use in the iRoom ubiquitous computing environment.