Auto-summarization of Design History by Event Ranking
lFinal Design: 12
lUser Marked Significant Event: 11
lCreation of an Existing Agent: 10
lCreation of an Existing General or Interface Class: 9
lCreation of an Existing Speech Grammar: 8
lCreation of an Existing Association: 7
lCreation of an Existing Unrecognized Stroke: 6
lText Update: 5
lMovement: 4
lCreation of Deleted Object: 3
lDeletion of an Object: 2
lUndo/Redo: 1
Designers may also want to ask the more general question “How did we design this system?”  We would like to present to the designer a visual description of how the scene evolved.  We don’t want to show the designer all of the significant events.  Rather, we want to select a small number of snapshots that when combined together can best display the evolution of the design.  We want to select the most significant events to show to the user, and the most revealing snapshot related to those significant events.  Significant events are all given a rank.  For instance, creation of an Agent is given the highest rank of all sketched objects, with a rank of 10.
   The logic behind the initial ranking is as follows. The final event is always ranked the highest.  The designer selected significant events outrank computer selected significant events.  Creation of viewable objects is considered a more significant event than the updating or movement of that object.  Creations of objects that no longer exist in the final version are considered to be much less significant than those that remained throughout the entire process.
   Within a particular category (e.g., looking only at the Creation of Agent Events), events are again ranked as more or less significant. Events that affect more objects have a higher ranking. Events specifying the creation of agents, classes, and grammars are further differentiated by the number of associations attached to them, adding to the rank the total number of associations divided by 100.