Input-Output Technology

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Input-Output Technology

• Material SourceProfessor James Landay(UCB)
• John Kelleher
• (IT Sligo)

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Outline

• Input devices
• Output devices
• Future possibilities
• Questions

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Desirable Characteristics

• Human performance
• Speed, accuracy, learning
• Human protection
• Fatigue and comfort
• Repetitive stress injury
• Match to Special Environments
• Space and grime
• Hands occupied
• Minimal desk space or need to be mobile
• Match to Task
• Drawing, Dragging, Selecting

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Input Devices

• Keyboards
• Pointing Devices
• Handwriting Recognition
• Voice Input

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Keyboards

• Qwerty (1874)
• arrangement chosen to reduce jamming, by
  separating keys commonly used together
• Dvorak (1932)
• layout based on frequency of usage of letters,
  letter patterns, sequences in English
• all vowels frequently used consonants on home
  row (70 of common, 35 all on this row alone)
• evenly divided between left and right
• Chorded keyboards
• Carpel tunnel syndrome
• repetitive stress injuries (RSI)

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Dvorak Keyboard
Dvorak analyzed the English language and
improved typing speed by 15-20 and typing
accuracy by 50.
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Chorded Keyboard

• Several keys pressed at once to enter a single
  character
• Many combinations from few number of keys
• small
• can be operated with one hand
• currently used in wearable computing, courtroom
  recording, mail sorting

Twiddler - combination mouse chorded
keyboard - 12 finger keys - 6 thumb keys - gt
4000 combinations
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(No Transcript)
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Mouse

• Good for
• Pointing
• Selecting
• Dragging
• Grabbing
• Not so good for
• Drawing
• Cramped spaces

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Trackball

• Good for
• Pointing
• Selecting
• Portable computers
• Not so good for
• Drawing
• Dragging
• Fatigue

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Joystick

• Good for
• Games
• Flying aircraft
• Point designation
• Handicapped individuals
• Not so good for
• Drawing
• Fine selection

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Touch Screens

• Commonly used in kiosks and other walk-up-and use
  interfaces
• Good for
• Gross selection
• Novice Users
• Special environments
• Shop floor
• Kiosks
• Burger King
• Not Good for
• Constant use
• Drawing

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Touch Screens

• Pros
• easy to learn, no extra workspace, no moving
  parts, direct interaction
• Cons
• lack of precision, high error rate, arm fatigue,
  fingers obscure, screens smudge
• fastest, least accurate of cursor devices
• good for large targets, untrained users
• bad for frequent, high-resolution tasks or expert
  users

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Pen-based Tablets

• Good for
• Drawing
• Tracing
• Digitizing
• Handwriting
• Two handed input
• Not so good for
• Cramped spaces
• Selection

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Pros and Cons of Pointing Devices
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DataGlove

• Good for
• Grabbing
• Pointing
• Tactile sensation
• 3-D tasks
• Telerobotics
• Not so good for
• 2-D environments
• Drawing

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Gaze

• Gaze is the process of making menu selections
  with ones eyes
• Uses an eye tracking device
• Head mounted or heads up displays
• user has a see through visor in front of their
  eyes on which the computer display is projected
• fighter pilots and repair personnel doing complex
  repair tasks use head-mounted displays

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Gaze (contd.)

• Good for
• Handicapped personnel
• Tasks requiring both hands
• flying
• repair
• Not so good for
• Normal selection tasks
• Very tiring difficult to use

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Handwriting Recognition

• Display tablets
• LCD panel with a pen
• Computationally doable
• Issues
• printing vs. cursive writing
• custom-design alphabets
• shortcuts Graffiti, Unistrokes, etc.

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Graffiti

• All but one letter is single stroke
• Common letters fast (A, E, I, O, U)
• Less ambiguous (V vs. U, Y vs. J, etc.)

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Speech Recognition

• Issues
• continuous vs. discrete speech
• vocabulary size
• trained/untrained speaker
• sound environment
• noise
• type of mike
• context vs. commands
• Pro
• natural - training is simplified
• keeps hands free
• accessible to vision- and motor-impaired
• Con
• speech recognition complex
• background noise
• natural language difficult to interpret

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Special Keyboards

• designs to reduce fatigue for RSI
• for one handed use
• e.g. the Maltron left-handed keyboard