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Human Computer Interaction - PowerPoint by oOz7UeC

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									Human Computer Interaction
      and Usability
             Class 6
           LBSC 690
     Information Technology
                 Agenda

•   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
•   GUIs/WIMP
•   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
Human

        Mental Models     Sight
                          Sound

  Task          System    Hands
                          Voice


 User (Software) Models   Keyboard
                          Mouse

  Task           User     Display
                          Speaker
Computer
             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,
       knowledge/beliefs
  – 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
Agents
         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
       Evaluation/Usability
• 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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