Software Usability By: Robert J. Remington

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Software UsabilityBy Robert J. Remington

• EEL6883 Software Engineering II
• Dr. Turgut University of Central Florida
• Presented By Adam Radwan
• 19 February 2007

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Introduction

• Initial thoughts
• Frequently software engineers would like to know
  if there are any good resources and documentation
  for designing a good GUI
• No magic bullet in design, rather there is a set
  of rules and suggestions outlined in SWEBOK
• IBM Report 42 of users avoided ordering from
  the web when presented with a poorly designed
  user interface

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Software Quality

• Six ISO Standard high-level characteristics to
  describe software quality
• Functionality
• Reliability
• Efficiency
• Maintainability
• Portability
• Usability

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Usability

• Usability definition characteristics relating
  to the effort needed for use, and on the
  individual assessment of such use, by a stated or
  implied set of users
• Discussion What does this definition actually
  mean? Do the users have any implied
  prerequisites for system use?

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Usability

• Five characteristics
• Understandability
• Learnability
• Operability
• Attractiveness (misspelled in the article)
• Compliance to application-related standards,
  conventions, regulations in law, and protocols

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Usability Engineering (UE)

• Human-Computer Interaction (HCI) mismatches have
  caused fatal mistakes
• Casey (Santa Barbara, CA 93) reports a case
  where a radiotherapy accelerator proton beam
  delivered a lethal 25 M eV as a result of a
  poorly designed, buggy user interface
• Usability Professionals Association (UPA) formed
  at ACM SIG-CHI 92 by 30 delegates now over 2000
  members

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UPA resources

• Body of Knowledge spans studies done at 63
  research and development centers
• Over 350 articles and laboratory reviews
• Human-Computer Interaction journal publishes many
  up-to-date articles
• As a result, UE has expanded its process models,
  design standards, and evaluation methodology all
  combines into user-centered development (UCD)

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User-Centered Development

• UCD process (ISO 13407) lists 4 activities
  undertaken during a project
• Understand and specify the context of use
• Specify the user and organizational requirements
• Produce design solutions
• Evaluate designs against requirements

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Usability Design Standards

• ISO 9241 lists standards and guidelines for
• Displayed colors
• Dialog principles
• Presentation of information
• User Guidance
• Menu Dialogs
• Form-filling Dialogs

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Rapid Prototyping

• Creation of a limited, functional user interface
  for a test drive proven effective
• Allows for feedback to be obtained in earlier
  stages of development
• Helps avoid errors resulting in design problems
  from miscommunication about user requirements

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Software Usability Evaluation

• Evaluation should take places at all stages of
  development
• Research centers often use laboratories with
  one-way mirrors, microphones, and cameras to
  monitor how a user may interact with a system for
  the first time
• Fitted curve can estimate the number of problems
  uncovered based on the number of evaluated users
• 5 users usually uncover approx. 80 of errors

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Future Challenges

• Web-based user interfaces have been a limiting
  factor compared to traditional GUI development
• Smaller display size and limited input of mobile
  applications are current drawbacks with many
  portable implementations
• Some systems for I/O and control may best be kept
  on larger form-factor equipment

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Summary

• No single proven technique for development of
  high-usability software
• Usability Engineering becoming more advanced,
  contributions have increased overall software
  product quality
• Further HW/SW advances may solve some known
  limitations and drawbacks

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Questions?

• Any questions?
• Time permitting, brief navigation to several
  websites displaying examples of usability