C SCI 4600 - In-Class Exercise No. 5
C SCI 4600 -- The Human-Computer Interface
Spring Semester, 2002

Tuesday, February 26, 2002

The Goal: To design an alternative graphical user interface for a PDA which is specifically tailored to overcome the drawbacks caused by the device's small size. NOTE: This is an open research problem!

The Scenario: In our first in-class exercise you speculated on the functionality we might find in tomorrow's PDAs. This time, we will take today's PDAs as our hardware platform, and focus on one of the major annoyances users of these devices encounter--namely, inconvenience due to what Marcus calls the "baby face" display. The tiny screen size makes it impractical for a PDA to show anything approaching the amount of information we are accustomed to on our laptops and desktop PCs. So common tools such as Web browsers become problematic to implement smoothly. This phenomenon is not due to limitations in current technology; even if the display's resolution supported the presentation of an entire Web page at a time, it would still be useless because the fonts would be so small nobody could read the text.

Benjamin Bederson, now at the University of Maryland, has proposed an approach he calls zoomable user interfaces, or ZUIs, which may help alleviate this problem (interestingly, he began this line of research for his dissertation, which was unrelated to possible applications to PDAs). The basic idea is that unlike in a conventional GUI, in a ZUI one doesn't try to squeeze everything onto the screen at once. Instead, information is organized hierarchically and displayed a level or two at a time. Any part of the screen may contain additional information, which can be revealed by zooming in and later hidden again by zooming back out. These operations may be repeated to as many levels as desired. So user interaction in a ZUI involves lots of zooming in (to see more detail) and out (to restore the overview), coupled with panning (left/right, up/down) to change the focus. Although ZUIs are attractive in certain ways the approach is not without problems (e.g., "desert fog" in which the screen appears blank and the user cannot figure out where s/he is relative to the information space), as we shall see later in the term when we view video clips from recent conference presentations on this topic by Bederson and others.

What To Do: In preparation for Tuesday's class, point your Web browser at Ben Bederson's home page   http://www.cs.umd.edu/$\sim$bederson   then click on "ZUIs" in the "Research" cluster of links and follow the example. (Exploring the rest of Bederson's site is also worthwhile!) Can you come up with preliminary ideas for possible ways in which a zoomable user interface--or perhaps some other approach or combination of techniques!--might effectively be employed on a PDA to compensate for the device's small display? To help focus your thoughts in a concrete manner, consider the specific problem of a new Web browser that would be superior to conventional tools such as Netscape or MS/Internet Explorer for this class of device. Feel free to make whatever reasonable assumptions you think necessary.

When you come to class on Tuesday, as is our custom we will divide up into small teams of 3-4 members each and rearrange seating as necessary to facilitate interaction. Each team member should try to "sell" his/her vision for a PDA ZUI to the team as a whole. The team should select and combine the individual members' best ideas, to develop specifics of the interface. Towards the end of the session, I will call for volunteers from several teams to present their designs to the class, so as you work you should also prepare a few overheads that convey an idea of your team's vision.

As usual, after the conclusion of the in-class part of the exercise your team should summarize its designs and the lessons learned in a written report which includes diagrams and illustrations as needed. Discuss what you perceive to be the advantages of your designs, and also possible problems. The report (one copy with all team member names listed) is due ten days after the in-class phase of the exercise is completed.