June 2010 Edition
Computer Science Department, University of Cape Town
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This module is about the design and evaluation of a class of systems that were not even envisaged until relatively recently.
Until the 1980s almost all commercial computer systems were non-interactive. Computer operators would set-up the machines to read in large volumes of data – say customers bank details and transactions – and the computer would then process each input and generate appropriate output.
There are still lots of these systems in place but the world is also now full of interactive computer systems. These are systems that involve users in a direct way.
In interactive systems the user and computer exchange information frequently and dynamically. Norman’s evaluation/execution model is a useful way of understanding the nature of interaction:
User has a goal (something to achieve)
User looks at system and attempts to work out how he would execute a series of tasks to achieve the goal.
User carries out some actions (providing input to the system by pressing buttons, touching a screen, speaking words etc)
System responds to the actions and presents results to the user. System can use text, graphics, sounds, speech etc.
User looks at the results of his action and attempts to evaluate whether or not the goals have been achieved.
A good interactive system is one where:
User can easily work out how to operate the system in an attempt to achieve his goals.
User can easily evaluate the results of his action on the system.
This course is about methods, tools and techniques that can be used to ensure that the user and computer can interact effectively. We will be looking, then, at the Human-Computer Interaction (or HCI) elements of systems design.
What interactive systems do you use in your day-to-day life? Your first response might be to identify the Personal Computer and all its applications. However, the term ‘interactive system’ can be applied to a much broader range of devices, for example:
Mobile telephones
Cash dispensing machines
The World Wide Web
Car navigation systems
Video recorders
Machines driven call centres (e.g. for telephone banking).
Workflow system to co-ordinate a teams work-efforts.
Over the next week, keep a log of all the times you use an interactive computer system. For each encounter record:
The goal you were trying to achieve.
How easy the interactive system was to use as you attempted to complete your tasks.
Any problems or frustrations you had with the system.
Any improvements you would suggest to the system.
A discussion of this activity can be found at the end of the chapter.
In his book, ‘The Invisible Computer’Don Norman argues the case for ‘information appliances’. He suggests that the PC is too cumbersome and unwieldy a tool. It has too many applications and features to be useful. He sees the future as being one where we use specific ‘appliances’ for specific jobs.
Norman envisions a world full of information appliances, a world populated by interactive computer systems:
The home medical advisor: sensors in the home will enable blood pressure, temperature, weight, body fluids and so on to be automatically monitored. A computer could use these readings to assist with medical advice or to contact a human doctor.
Digital picture frames: give this frame to a friend or relative. When you have taken a new picture you want them to share, simply ‘email’ the picture direct to the frame. The frame will be connected to the net wirelessly.
The weather and traffic display: at the moment, when we want the time we simply look at a clock. Soon, perhaps, when we want to know the weather or traffic conditions we will look at a similar device.
Embedded systems within our clothes: ‘consider the value of eyeglass appliances. Many of us already wear eye glasses … why not supplant them with more power? Add a small electronic display to the glasses … and we could have all sorts of valuable information with us at all times’ [Norman 99, pg 271-272]
Many people believe we will soon enter an age of ubiquitous computing – we will be as used to interacting with computing systems as we are with other people. This dream will only be fulfilled if the businesses that produce these systems and services clearly understand the needs of users so that the systems can be useful and usable.
How does an interactive system differ from a non interactive system? Give examples of types of both systems.
Answer to this question can be found at the end of the chapter.
What does the term ‘ubiquitous computing’ mean?
Answer to this question can be found at the end of the chapter.