Browsing by Author "Bohnet, Ralph"
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- ItemOpen AccessGROUP SKETCH: A MULTI-USER SKETCHPAD FOR GEOGRAPHICALLY-DISTRIBUTED SMALL GROUPS(1990-11-01) Greenberg, Saul; Bohnet, RalphRecent research observations of small group meetings have identified factors critical to the design of computer tools supporting real time collaborative design. In particular, group activity revolves as much around the design process--sketching, annotating, listing ideas, and gesturing around a communal work surface--as it does around the resulting drawing artifact. A workstation-based tool called GroupSketch has been developed that allows a small geographically-distributed group to list, draw, and gesture simultaneously in a communal work surface, supporting interactions similar to those occurring in the face-to-face process. GroupSketch facilitates collaboration by: a) allowing gestural expression through large unique cursors visible on all displays; b) minimizing overhead encountered in storing information; c) conveying the process of expressing ideas by transmitting small granular changes of user activity with minimum time delay; d) intermixing gestural, textual, and graphical expression modelessly; and e) providing simultaneous access to a common view of the work surface area. Observations drawn from actual design sessions indicate that people use GroupSketch in much the same way they use face to face communal sketchpads.
- ItemOpen AccessISSUES AND EXPERIENCES DESIGNING AND IMPLEMENTING TWO GROUP DRAWING TOOLS(1991-07-01) Greenberg, Saul; Roseman, Mark; Bohnet, Ralph; Webster, DaveGroupware designers are now developing multi-user equivalents of popular paint and draw applications. Their job is not an easy one. First, human factors issues peculiar to group interaction appear that, if ignored, seriously limit the usability of the group tool. Second, implementation is fraught with considerable hurdles. In particular, contemporary window systems and their user interface toolkits actually inhibit implementation efforts by failing to provide adequate building blocks for constructing group interface primitives and by not supplying an adequate architectural infrastructure. This paper describes the issues and experiences we have met and handled in the design of two systems supporting remote real time group interaction: \fIGroupSketch\fR, a multi-user sketchpad; and \fIGroupDraw\fR, an object-based multi-user draw package. On the human factors side, we summarize empirically- derived design principles that we believe are critical to building useful and usable collaborative drawing tools. On the implementation side, we describe our experiences with replicated versus centralized architectures, schemes for participant registration, multiple cursors, network requirements, and the structure of the drawing primitives.