Normans 7stage model and Direct manipulation

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Normans 7-stage modeland Direct manipulation

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Agenda

• Questions?
• Reminder
• Poster session feedback
• Part 2 writeup pointers
• Announcement
• Pen gesture interfaces
• 7-stage model of interaction
• Where do errors occur in the model?

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Reminder Talk today

• Today (6/14) 4-500PM, TSRB Auditorium
• Daniel Rosenberg, VP of RD in Usability and
  Interface Design at Oracle
• Overview of lab, organization, and projects
• Largest single HCI organization in Silicon Valley

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Poster feedback

• Great job!
• Good prototypes good depth and lots of
  creativity!
• Useful? Good feedback?

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Part 2 writeup tips

• Get feedback from your users, on both prototypes
  and scenarios
• Iterate on your designs tell us what kind of
  feedback your iterations are based on
• Relate your prototypes to your usability
  criteria these are your design guidelines
• Talk about the functional and non-functional
  requirements of each prototype
• And finally.

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Part 2 writeup tips (cont.)

• Incorporate and synthesize design concepts from
  class!
• Closure problem, problem of levels, constraints
  (cultural, logical, physical, semantic), forcing
  functions, direct manipulation, feedback,
  visibility, natural mapping, knowledge in the
  world v. knowledge in the head, working memory

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Announcement

• Midterm is on 6/23
• Sample exams are posted on web
• You have fewer exams in this class, but they will
  be longer
• Basically same format as sample exams

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Pen and Gesture

• Another natural input
• Relies on recognition
• Does not imply reciprocal output

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Handwriting recognition

• On-line or off-line
• Individual variation
• Variation within single users handwriting
• Requires training
• Difficult to distinguish individual letters

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Unistrokes

• Single stroke handwriting recognizer
• Xerox PARC -- PARC Tab
• Took advantage of screen borders

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Graffiti

• Palm Pilot
• Very similar to Unistroke
• Physical design matters
• Recently lost lawsuit to PARC

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Quickwrite (Perlin)

• Single stroke
• Memorize?

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Cirrin (Mankoff)

• Word-level single stroke recognizer

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Mixing modes of pen use

• Users want free-form and commands
• or commands vs. text
• How to switch between them?
• (1 mode) recognize which applies
• (2 modes) visible mode switch
• (1.5 modes) special pen action switches

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Correcting recognition errors

• Really slows effective input
• word-prediction can prevent errors
• Various strategies
• repetition (erase and write again)
• n-best list

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Other interesting applications

• Signature verification
• Note-taking
• group (NotePals by Landay _at_ Berkeley)
• student (StuPad by Truong _at_ GT)
• meetings (Tivoli and other commercial)
• Sketching systems
• early storyboard support (SILK, Cocktail Napkin)

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Gesture Recognition

• Tracking 3D hand-arm gestures
• fiber optic, e.g. dataglove
• magnetic tracker, e.g. Polhemus
• vision-based, e.g. Barehands
• Perceptual user interfaces
• emerging area
• mainly computer vision researchers

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Advantages

• Using Wizard of Oz techniques, we find
• Consistent gestures for certain commands
• Easy to learn
• Remembered over time

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Implications for design

• Scenarios should include errors !!!
• Distinguish between skilled and learner errors
• Uncover errors in the existing system
• how do people self-monitor (cheat sheets)
• Dont forget closure

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Execution Evaluation Cycle

• Norman (DOET, p.46)
• Simple idea
• Perform
• Assess
• 7 stages

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Stage Goal formation

• Vaguely stated
• Something to be achieved

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Stage Intention formation

• Deciding to act to achieve goal

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Stage Action specification

• Determining sequence of specific actions based on
  intention

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Stage Action execution

• Physically carrying out the actions to address
  the intention
• Has some effect on the world

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Stage Perceiving the world state

• Physically perceiving the new state of the world
  (sensory)

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Stage Interpreting perceptions

• Making semantic sense of the sensory input

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Evaluating the interpretations

• Determining whether the perceived effect was the
  desired one
• What happens if not?

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Applying the model
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Two sides to the model

• Gulf of execution What do we do to achieve the
  change in the world?
• Gulf of evaluation What do we do to understand
  the change in the world?

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Two ways of thinking about interaction

• Conversation metaphor
• Interaction through
• Model-world metaphor
• Interaction with

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Distance

• Amount of effort to convert goals into physical
  action
• Relates to the 7-stage model

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Semantic Distance

• Can I say what I want?
• Can I say it concisely?
• Gulf of Execution (spreadsheet example)
• Gulf of Evaluation (beep vs. error description)

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Articulatory Distance

• Relationship between meaning and form
• Gulf of execution
• (e.g. scrolling vs. typing a command)
• Gulf of evaluation
• (e.g. audio feedback in computer volume control)

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You try it

• Think of a slip or error youve made
• What kind of slip is it?
• Where did it occur in the 7-stage cycle?
• What kind of distance yielded the problem?

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Upcoming

• More on direct manipulation
• Read Hutchins, Hollan Norman (on web page)
• DFAB 4.2.7