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Unit 12 Interacting with Information



Three Mile Island nuclear power plant

On Wednesday, 28 March 1979, at 4am, several water pumps
stopped working at eh Three Mile Island nuclear power plant in Pennsylvannia, USA.
In the control room, an alarm sounded.  It was rapidly followed by a cascade of
100 different alarms, each indicating some separate failure. Although there was a single
acknowledge button that could silence all alarms at the same time, it could not be
used as the operators would not then be able to tell where the original fault lay.

The incident nearly resulted in the meltdown of the nuclear reactor.



In the Three Mile Island nuclear power plant, the operators' job of dealing with
failure wasn't made easy: the control room included over 1500 alarm conditions
with a confusing layout of the control panel.  If that wasn't enough, there was no
easy way of isolating the more critical alarms - those that needed immediate
attention, for pump failure, for instance - from those that were less important.

The importance of good user interface is not limited to nuclear power plants.

Boo.com
The Space Shuttle Challenger

Getting the design of a system's user interface right, is important for the safety
of humans and systems.  It is also important if you just want to give customers
a way to spend their money.  Presenting data in a way that provides useful
information can help us to make sense of the data and to take the right decisions.

In this unit:

• the significance of the design of usable computer systems;
• usability principles that any user interface designer needs to bear in mind;
• how to help the user to make sense of any data being visualised;
• how to apply the principles of visual design and data visualisation to the design of a website.

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