evaluation

This paper explores architectural support for interfaces combining pen, paper, and PC. We show how the event-based approach common to GUIs can apply to augmented paper, and describe additions to address paper's distinguishing characteristics. To understand the developer experience of this architecture, we deployed the toolkit to 17 student teams for six weeks. Analysis of the developers' code provided insight into the appropriateness of events for paper UIs. The usage patterns we distilled informed a second iteration of the toolkit, which introduces techniques for integrating interactive and batched input handling, coordinating interactions across devices, and debugging paper applications. The study also revealed that programmers created gesture handlers by composing simple ink measurements. This desire for informal interactions inspired us to include abstractions for recognition. This work has implications beyond paper - designers of graphical tools can examine API usage to inform iterative toolkit development.

The development of user interface systems has languished with the stability of desktop computing. Future systems, however, that are off-the-desktop, nomadic or physical in nature will involve new devices and new software systems for creating interactive applications. Simple usability testing is not adequate for evaluating complex systems. The problems with evaluating systems work are explored and a set of criteria for evaluating new UI systems work is presented.