Petri nets in the evaluation of collaborative systems

Petri nets were conceived by Carl Petri as a mathematical means of describing activities, resources, and states of a system. They have been used to model, analyze and evaluate control system behavior. They have also been used in software engineering. More recently, Petri nets have been used to describe the behavior of computer supported workflows and extended to apply to protocols appearing in collaborative systems comprised of human participants and multiple resources including oral communication and electronic interaction. In every case, the Petri nets are modeling protocols. These interaction management rules include interfaces among real machines, virtual machines and humans. The paper describes Petri net modeling in the context of a study of team interactions in a mixed media lab setting. Analysis of extensive records of team speech and use of computer tools available to each member, led to empirically derived Petri nets which capture actual behavior, including the evolution of team preferred protocols. Among these were synergies between member communications via distinct media. Specifically, throughout the study, the participants, unbeknownst to them, were learning to use oral communication to change the protocols which were assigned for the electronic medium. The change in behavior was so subtle that only through evaluating the transcripts and creating Petri net models to capture observed behavior was this made clear