9. Interaction Devices

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9. Interaction Devices

• Keyboards and Function Keys
• Keyboard layouts
• QWERTY layout (Christopher Latham Sholes), Dvorak
  layout, ABCDE style
• number pads telephone layout and calculator
  layout
• wrist and hand placement awkward
• Keys
• ½-inch-square keys (12 mm square) with about
  ¼-inch space (6 mm square) between keys
• concave surface with a matte finish
• 40- to 125-gram force and a displacement of 3 to
  5 mm, tactile and audible feedback
• larger for reliable access, locking by embedded
  light, labels, home keys (F and J)
• Function keys
• Cursor movement keys
• typamatic (auto-repeat) feature
• Pointing Devices
• Pointing tasks
• 6 types of interaction tasks -- Select, Position,
  Orient, Path, Quantify, Text
• direct control (light pen, touchscreen, stylus)
  vs. indirect control (mouse, trackball, joystick,
  etc)
• Direct-control pointing devices
• lightpen incorporate a button arm fatigue,
  hands obscuring part of the screen, users
  removing hands from the keyboard, picking up the
  lightpen

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• touchscreen (fatigue, obscuring the screen, hand
  off keyboard, imprecise pointing, smudging of the
  display) land-on strategy, lift-off strategy
• pointing on the LCD surface handwriting
  recognition, stylus
• Indirect-control pointing devices
• more cognitive processing and hand-eye
  coordination
• mouse, trackball, joystick, trackpoint, graphics
  tablet, touchpad
• Comparisons of pointing devices
• speed of motion, accuracy of positioning, error
  rates, learning time, user satisfaction
• cost, durability, space requirements, weight,
  left- versus right-hand use, likelihood to cause
  repetitive-strain injury, compatibility with
  other systems
• direct pointing devices fastest but the least
  accurate devices
• indirect pointing devices -- mouse was found to
  be faster than the isometric joystick
• pointing devices are faster than keyboard control
• Fitts Law
• the pointing time is a function of the distance
  and the width
• Index of difficulty log2(2D/W)
• Novel pointing devices
• foot controls, eye-tracking (Midas touch
  problem), DataGlove,
• Speech Recognition, Digitization, and Generation
• Discrete-word recognition
• recognize individual words spoken by a specific
  person 90-98 reliability for 20-200 words

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• speaker dependent training, speaker independent
  system
• hands are busy mobility required eyes
  occupiedharsh or cramped conditions
• recognition rate background sounds change, user
  is ill or under stress, similar vocabulary
• Continuous-speech recognition
• difficulty in recognizing the boundaries between
  spoken words
• Speech store and forward
• Speech generation
• synthesis in some cases, removal of speech
  generation
• Audio tones, audiolization, and music
• audio tones confirmation for most users, vital
  for the impaired after 2 hrs, distraction
• Image and Video Displays
• Display devices
• CRT, LCDs, Plasma panel, LEDs
• Digital photography and scanners
• Digital video
• Projectors, heads-up displays, helmet-mounted
  displays
• Printers
• dot-matrix printers, inkjet printers, thermal
  printers
• line printers, laser printers

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10. Response Time and Display Rate

• Introduction
• response time the number of seconds it takes
  from the moment users initiate an activity until
  the computer begins to present results o the
  display or printer
• lengthy (gt 15 sec) response time ?
  productivity,?error rate, ?satisfaction
• more rapid (lt 1 sec) ? productivity, ? error
  rate
• display rate the speed, in characters per
  second (cps), at which characters appear for the
  user to read graphics in bytes per seconds
• Theoretical Foundations
• Limitations of short-term and working memory
• Miller (1956) the magical number seven plus
  or minus two ? seven chunks of info. in working
  memory for 15 to 30 seconds knowledge and
  experience
• STM processes perceptual input, whereas WM is
  used to generate and implement solutions
• Sources of errors
• interference, delay preferred response time
• long response time leads to wasted effort and
  more errors because a solution plan is reviewed
  repeatedly
• shorter response times may generate a faster pace
  in which solution plans are prepared hastily and
  incompletely
• Conditions for optimum problem solving
• Wickelgren (1977) -- speed-accuracy tradeoffs
• feedback -- graphical dynamic progress indicators

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• rapid task performance, lower error rates, high
  satisfaction
• other conjectures may play a role in choosing the
  optimum interaction speed
• Expectations and Attitudes
• acceptable response time 2-second limit
• Previous experience 2. Individual personality
  differences 3. Task differences
• three conjectures
• User Productivity
• Repetitive tasks
• monitoring a display and issuing commands in
  response to changes in the display
• with shorter system response times, the operator
  picks up the pace of the system and works more
  quickly, but decisions on commands may be less
  than optimal
• Problem-solving tasks
• users will adapt their work style to the
  response time
• the time to solution was invariant with respect
  to response time ? users will change their work
  habits as the response time changes
• Variability
• people detect 8-percent changes in a 2 or 4 sec
  response time
• modest variations in response time do not
  severely affect performance adapting
• an increase in variability of response time does
  not have any negative influence on the performance

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11. Presentation Styles

• Color
• use color conservatively
• limit the number of colors
• recognize the power of color as a coding
  technique
• ensure that color coding supports the task
• have color coding appear with minimal user effort
• place color coding under user control
• design for monochrome first
• consider the needs of color-deficient users
• use color to help in formatting
• be consistent in color coding
• be alert to common expectations about color codes
• be alert to problems with color pairings
• use color changes to indicate status changes
• use color in graphic displays for greater
  information density

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13. Multiple-Window Strategies

• Introduction
• the need to consult multiple resources rapidly,
  while minimally disrupting the concentration on
  tasks
• window housekeeping
• windowed version of a system
• longer task-completion times than the
  non-windowed
• more time arranging info on the display and more
  scrolling activity
• the task-solution times were shorter for the
  windowed environment
• fewer errors
• Individual-Window Design
• window a rectangular area that contains a
  software application, or a document file
• window interface objects -- Titles, Borders or
  frames, Scroll bars
• window interface actions -- Open, Open place and
  size, Close, Resize, Move, Activation
• Multiple-Window Design
• Multiple monitors / Rapid display flipping /
  Split displays / Space-filling tiling with fixed
  number, size, and place / Space-filling tiling
  with variable number, size, and place /
  Non-space-filling tiling / Piles of tiles /
  Window zooming / Arbitrary overlaps / Cascade

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• Coordination by Tightly-Coupled Windows
• coordinated windows windows appear, change
  contents, and close as a direct result of user
  actions in the task domain
• coordination a task concept that describe how
  information objects change based on user actions
• tight coupling interface concept that supports
  coordination
• Synchronized scrolling
• Hierarchical browsing
• Direct selection
• Two-dimensional browsing
• Dependent-windows opening
• Dependent-windows closing
• Save or open window state
• Image Browsing by Tightly-Coupled Windows
• overview and detailed view (additional
  intermediate view)
• zoom factor 5-30 effective
• fisheye views
• visually appealing
• but changing distortion may be disorienting and
  zoom factor never exceeds 5

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14. Computer-Supported Cooperative Work

• Goals of Cooperation
• cooperation by the goals and tasks of the
  participants
• Focused partnership cooperation between two
  users email, voice mail, telephone, video mail
• Lecture or demo one person sharing info with
  many users at remote sites the start time and
  duration is the same for all no history keeping
• Conferences groups communicate at the same time
  or spread out over time, but with participants
  distributed in space a record of previous
  conversation
• Structured work processes let people with
  separate roles cooperate on some task
• Electronic Commerce negotiations can be
  distributed in time and space
• Meeting and decision support face-to-face
  meeting with simultaneous contributions
  anonymity
• Teledemocracy
• time-space matrix (Ellis et al., 1991)
• Asynchronous Interactions Different Time,
  Different Place
• Electronic Mail
• Newsgroups and network communities
• newsgroups tools to organize the discussion and
  provide an accessible historical record
• listserv more orderly community structure
  individuals must subscribe to receive email
  notices
• online conference voting and using online
  directories
• newsgroups or listservs are usually open to all,
  whereas conferences are to only known communities

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• online magazines and newsletters
• shareware, freeware, public-access software
• Synchronous Distributed Different Place, Same
  Time
• group editing multiple users edit the same
  document simultaneously. coordination by voice
  communication
• MUD (multi-User Dungeons or Dimensions system)
  delays, locking, sharing, synchronization
• video conferencing, DTVC (desktop
  videoconferencing) slow response time,
  background noise, inappropriate lighting, eye
  contact difficulty, small image size, privacy
  invasion, jerky motion
• Face to Face Same Place, Same Time
• Shared display from lecturer workstation
• Audience response units
• Text-submission workstations
• Brainstorming, voting, and ranking
• File sharing
• Shared workspace
• Group activities
• Applying CSCW to Education

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15. Information Search and Visualization

• Introduction
• information retrieval ? information gathering,
  seeking, filtering, or visualization
• database management ? data mining, warehousing or
  knowledge networks
• information search using traditional UI hurdle
  for novice users and an inadequate for experts
• task objects are represented by interface objects
  in structured relational databases,
  textual/multimedia document libraries
• task actions
• fact finding browsing or searching
• interface actions scrolling, zooming, joining,
  or linking
• Tasks specific/extended fact finding,open-ended
  browsing, exploration of availability
• Database Query and Phrase Search in Textual
  Documents
• SQL requires training, and even then users make
  frequent errors
• query-by-example, form-fillin queries
• walk-up kiosk or textual-document library
  searches -- keywords/natural-language queries
• four-phase framework
• Formulation expressing the search ? source,
  fields, phrases, variants
• Initiation of action launching the search ?
  explicit, implicit initiation, dynamic query
• Review of results reading messages and outcomes
  ? sequence and cluster
• Refinement formulating the next step ? history
  buffer

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• Multimedia Document Searches
• Photo search -- query by image content search
  for distinctive features or search for
  distinctive colors
• Map search search by features
• Design or diagram search, Sound search, Video
  search, Animation search
• Information Visualization
• visual-information-seeking mantra overview
  first, zoom and filter, then details on demand
• Data type by task taxonomy (TTT) and seven tasks
  (Box 15.2)
• 1-D Linear Data
• organized in a sequential manner textual
  documents, program source code, alphabetical list
• what fonts, color, size to use, and what
  overview, scrolling, or selection methods can be
  used
• bifocal display, value bars
• 2-D Map Data
• task domain attributes (name, owner, value) and
  interface domain features (size, color, opacity)
• user tasks to find adjacent items, containing
  items and paths between items and to perform the
  seven basic tasks
• 3-D World
• molecules, the human body, and buildings

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• user tasks adjacency plus above-below and
  inside-outside relationships, the seven basic
  tasks
• position and orientation, occlusion overviews,
  landmarks, perspective, stereo display,
  transparency, and color coding
• Temporal data
• items have a start and finish time, and that
  items may overlap
• finding all events before, after, or during time
  period and the seven basic tasks
• Multidimensional data
• items with n attributes become points in a
  n-dimensional space
• finding patterns, clusters, correlations, gaps
  and outliers
• three-dimensional scattergram -- disorientation
  and occlusion
• Tree data
• fixed-level trees, fixed fanout trees
• 3-D cone, cam trees, dynamic pruning in the
  TreeBrowser, animated hyperbolic trees
• Network data
• shortest or least costly paths connecting two
  items or traversing the entire network
• Overview task
• movable field-of-view box, fisheye strategy
• Zoom task
• Filter task

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• Details-on-demand task
• simply click on an item to get a pop-up window
  with values of each of the attributes
• Relate task
• History task
• history of actions to support undo, replay, and
  progressive refinement
• Extract task
• Advanced Filtering
• dynamic queries (direct manipulation queries)
• full Boolean expression, filter-flow approach,
  SDI, collaborative filtering

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16. Hypermedia and the WWW

• Hypertext and Hypermedia
• Golden Rules of Hypertext
• There is a large body of information organized
  into numerous fragments.
• The fragments relate to one another.
• The user needs only a small fraction of the
  fragments at any time.
• poor design of hypertext
• too many links, long chains of links to reach
  relevant material, too many dull articles
• an overview can be presented to the reader in an
  introductory article
• hypertext database
• Know the users and their tasks / Ensure that
  meaningful structure comes first / Apply diverse
  skills / Respect chunking / Show
  interrelationships / Ensure simplicity in
  traversal / Design each screen carefully /
  Require low cognitive load
• introductory overview
• Executive overview
• Top-down
• Menu
• Search strategy
• the optimal length of articles
• many short articles are preferable to a small
  number of long articles

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• Genres and Goals for Designers
• the originators identity individual, group,
  university, corporation, or government agency
• goals of the originators
• the number of web pages or amount of accessible
  information
• measures of success
• Users and Their Tasks
• first time users, intermittent, frequent users
• tasks range from specific fact finding to more
  unstructured open-ended browsing of known
  database, to exploration of the availability of
  information on a topic
• Object-Action Interface Model for Web Site Design
• Web-Page design
• Compactness and branching factors -- page length
  and number of links (branching factor)
• Sequencing, clustering, and emphasis within a
  page
• Support for universal access
• Good graphical design
• Navigation support
• Testing and maintenance of web sites