Iconic system with extension mechanism

Iconic systems that function as if a display screen is a workspace in the real world have recently been proposed. Specification of an iconic system consists of an icon set and a rule set. However, specification of an iconic system for an application environment changes in accordance with the progress of the environment. We present a mechanism for extending iconic systems, and propose PROGRESS, an iconic system with the extension mechanism. In PROGRESS, the extension mechanism makes it possible to adapt the icon set and the rule set to the progress of the environment. The mechanism also makes specification more understandable by illustrating the iconic system with a directed graph. Extension is carried out visually by modifying the graph. Test results showed that the graphical extension mechanism reduced the occurrence of errors and the extension time. We conclude that the extendibility of PROGRESS is superior to other existing iconic systems.