2. the computer


Pick one of the following scenarios, and choose a suitable combination of input and output devices to best support the intended interaction. It may help to identify typical users or classes of user, and identify how the devices chosen support these people in their tasks. Explain the major problems that the input and output devices solve.

Environmental database

A computer database is under development that will hold environmental information. This ranges from meteorological measurements through fish catches to descriptions of pollution, and will include topographical details and sketches and photographs. The data has to be accessed only by experts, but they want to be able to describe and retrieve any piece of data within a few seconds.

Word processor for blind people

A word processor for blind users is needed, which can also be operated by sighted people. It has to support the standard set of word-processing tasks.

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The environmental database will be operated by skilled experts. It is likely that they will want geographic displays of information, so leveraging off of operations on a map seem likely to be intuitive. Various parameters would likely be overlaid on the map, so some intuitive way to select among parameters, possibly with a purpose-built keyboard with function keys representing the parameters to be revealed. There should be an analysis of current practices by these experts in which the way they like to view information is revealed and the way they like to manipulate information. It seems that an interface to encourage exploration to reveal trends in data would be useful, so how this exploration can be made natural would impact design recommendations for input devices.

The word processor for blind people that can also be used by sighted people is more challenging because you need to accommodate two very different modes of interaction. Blind users cannot rely on the visual domain. One approach is to take an existing word processor and attempt to modify it for non-sighted use. It is clear that some level of audio feedback would be useful. Perhaps a screen reader to assist in reading the contents of the text window. The prosody of the voice might indicate formatting of the text (for bold, italics, headings). Providing a chorded keyboard for input might be easier for the blind user, as orientation on a traditional keyboard might prove difficult without a lot of training. Two handed input techniques would also be useful, whereby one hand could be used for chording/typing text and the other for performing tasks. Audio feedback on commands would be useful, but the granularity of feedback would have to be experimented with.

Other exercises in this chapter

ex.2.1 (open), ex.2.2 (tut), ex.2.3 (open), ex.2.4 (tut), ex.2.5 (tut), ex.2.6 (tut), ex.2.7 (ans), ex.2.8 (ans), ex.2.9 (open)

all exercises for this chapter