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Human Computer Interaction - PowerPoint by oOz7UeC


									Human Computer Interaction
      and Usability
             Class 6
           LBSC 690
     Information Technology

•   Questions
•   Human computer interaction
•   Mental models and user models
•   Input/Output/Interactivity
•   Visualization
•   Usability/evaluation
Human-Computer Communications
 • Humans are slow but versatile devices
   – 120-300 words per minute
   – Multiple rich analog channels
 • Computers are fast but limited
   – Around 1 billion words per minute
   – Single digital channel for each task
 • The computer must slow down for us and
   we must sacrifice fidelity for the computer
       Styles of Interaction
•   Command-based
•   non-WIMP / SILK
•   Passive
•   Pervasive
             Input Devices
•   Keyboard
•   Pointing device (mouse, trackball, ...)
•   Joystick
•   Touch Panel, writing tablet
•   Speech recognition
•   Data-glove, head tracker, eye tracker, etc.
•   Video camera (lip-reading, gestures, etc.)
              Output Devices

•   Displays (CRT, flat panel, stereo, etc.)
•   Speakers, headphones, etc.
•   Printer (dot matrix, ink jet, laser, etc.)
•   Plotters, microfiche printers, etc.
•   Speech synthesizers
•   Full immersion (orientation, vibration, etc.)
 Mental Models and User Models

        Mental Models     Sight

  Task          System    Hands

 User (Software) Models   Keyboard

  Task           User     Display
             Mental Models
• The expectations the person has about how
  things work
• In particular:
  – how the computer and its software work
  – the information resources
                 User Models
• What the computer knows about the user
  – demographics
     • age, gender, nationality
  – technology capabilities
     • network, multimedia, CPU cycles
  – stable individual characteristics
     • height, languages understood, hometown,
  – transitory state of the individual
     • last book read, type of car, how hungry
       Using User Models

• A user model is not just data but ways of
  using those data (e.g., making predictions
  about a person).
• Ethical and legal issues about collecting
  personal information
• Anticipating the user vs. giving the user
  power tools
• Student models
         Direct Manipulation
• “Directly manipulate” conceptual objects
  – Windows file manager, Windows 95 Explorer
     • Compare this to DOS commands
  – Excel
     • Compare this to Java
• Often done with icons
  – But icon interpretation can be difficult
     • Too small, no good metaphor, cultural differences
  Language-Based Interfaces

• Alternative to direct manipulation
  – Compact, flexible representation
  – Can be hard to use
     • What can be done may not be apparent
     • Interpretation requires conceptual effort
• Examples
  – Text retrieval interfaces
  – Programming languages
               Menu Design
• Conserve screen space by hiding functions
  – Menu appears only when selected
• Can be logically grouped into several levels
  – But by who’s logic?
• Recognition (menus) vs. Recall
• Tradeoff between breadth and depth
  – Too broad and direct manipulation is better
  – Too deep and it can become hard to find things
     Information Visualization
• Using pictorial (spatial) relationships to
  show relationships in attributes
• Some basic visualization techniques
  – Lenses and filters
  – Context and hierarchies
  – Coordinated windows
• Example - real-estate browser
• Design interacts with usability
• Expert reviews
• Feedback from real users is helpful
  – Across a variety of realistic tasks
  – Across a realistic user sample of users
• Examine many aspects of the interaction
  – e.g., training, error messages, response time
Simulation and Virtual Reality
             HCI Summary

• HCI design starts with user needs + abilities
  – Users have a wide range of both
• Users must understand their tools
  – And these tools can learn about their user!
• Many techniques are available
  – Direct manipulation, languages, menus, etc.
  – Choosing the right technique is important
• This is the central focus of LBSC 795

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