Teams that are geographically distributed often share information both in real-time and asynchronously. When such sharing is through groupware, change conflicts can arise when people pursue parallel and competing actions on the same information. This leads to problems in how the systems and its users maintain a consistent view of shared information across distance and time. We explore change awareness of conflicts in a three-dimensional distributed shared space. Our user study compares the use of visual feedback to an optimistic concurrency control strategy for both synchronous and asynchronous distributed groupware. Our feedback provides a means for synchronous users to recognize and resolve real-time changes, and for asynchronous users to view and resolve changes when switching from an offline to online mode of work. Results of our study suggest that the visual feedback serves as a useful feedthrough mechanism in the synchronous case, but that asynchronous users may be overwhelmed b...
Mark S. Hancock, John David Miller, Saul Greenberg