Interpreted collaboration protocols and their use in groupware prototyping

The correct and timely creation of systems for coordination of group work depends on the ability to express, analyze, and experiment with protocols for managing multiple work threads. We present an evolution of the Trellis model that provides a formal basis for prototyping the coordination structure of a collaboration system. In Trellis, group interaction protocols are represented separately from the interface processes that use them for coordination. Protocols are interpreted (rather than compiled into applications) so group interactions can be changed as a collaborative task progresses. Changes can be made either by a person editing the protocol specification “on the fly” or by a silent “observation” process that participates in an application solely to perform behavioral adaptations. Trellis uniquely mixes hypermedia browsing with collaboration support. We term this combination a hyperprogram, and we say that a hyperprogram integrates the description of a collaborative task with the information required for that task. As illustration, we describe a protocol for a moderated meeting and show a Trellis prototype conference tool controlled by this protocol.