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• User Interface Design
– Chapter 16 +.
Importance of UI Design
• System users often judge system quality by its
interface rather than its functionality
– Computers are now being used by many non-technical
people
– Implementers are often poor judges of interface
acceptability and effectiveness
• Poor user interface design can decrease the
effectiveness, productivity and safety of software
intensive systems
– The interface to o ne tool may psychologically "interfere"
with the interface to another. Hence tool integration is
important
• A significant percentage of application code is
devoted to the user interface
– As much as 70% for some classes of applications
Human Factors
• Limited capacity of human short-term
memory; need to "chunk"
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Human Factors
• Limited capacity of human short-term memory;
need to "chunk"
• People make mistakes
• People have different interaction preferences
• People perform differently
– novice, knowledg eable intermittent, frequent expert
• Performance improves as people learn to use a
system
• Many human factor aspects of UI are measurable
• There exist some experimental results, but
technology is being driven by the market rather than
by research
