Enabling Instructional Applications on Pentop Computers
- Author(s): Lee, WeeSan
- Advisor(s): Stahovich, Thomas F
- et al.
While traditional computer interfaces based on the mouse and keyboard
are ubiquitous, they are ill suited to many common application
domains. This is particularly true in education, where recent research
suggests that students perform better when instructional interfaces
are more similar to work practice. Thus, the goal of our work is to
create computational techniques and user interface design principles
to enable natural, pen-based tutoring systems that scaffold students
in solving problems in the same way they would ordinarily solve them
with paper and pencil. In our work, we have focused on interfaces
suitable for a ``pentop computer,'' a writing instrument that is used
with special dot-patterned paper, and that has an integrated digitizer
and embedded processor. A pentop is capable of producing dynamic output
in the form of synthesized speech and recorded sound clips.
Accurate shape recognition is an essential foundation for developing
pen-based interfaces. We created a trainable, multi-stroke recognizer
that is insensitive to orientation, non-uniform scaling, and drawing
order. Symbols are represented internally as attributed relational
graphs describing both the geometry and topology of the symbols.
Symbol recognition is accomplished by finding the definition symbol
whose attributed relational graph best matches that of the unknown
symbol. We developed five efficient approximate matching techniques
to perform the graph matching.
To explore instructional and interface design issues, we created
Newton's Pen, a pentop-based statics tutor. This system, which is
intended for undergraduate education, scaffolds students in the
construction of free body diagrams and equilibrium equations.
Newton's Pen employs a finite state machine architecture that
effectively models the student's problem-solving progress, thus
serving as a convenient means for providing context-sensitive tutorial
feedback. User studies suggest that Newton's Pen is an effective
teaching tool, and that students are satisfied with the interface.
A key issue in the design of pentop interfaces is how to provide
effective feedback to the user. To explore this issue, we developed
PaperCAD, a system that enables users to query geometric information
from printed CAD drawings. PaperCAD employs two methods of feedback:
audio feedback with an adjustable level of conciseness, and a PDA that
provides a video display of the portion of the drawing near the pen
tip. This system also employs a novel technique that uses a hidden
Markov model to correct interpretation errors in hand-written
equations. Results of a user study suggest that users are highly
satisfied with the interface and prefer it to a traditional WIMP