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Interaction

Interaction. Gavin Sim. Aims of this lecture. Last week focused on persona and scenario creation. This weeks aims are: To introduce Interaction as a concept that links the human and the computer To begin to consider designing interaction. Inter - Action.

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Interaction

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  1. Interaction Gavin Sim HCI Lecture 4 - 2010/11

  2. Aims of this lecture • Last week focused on persona and scenario creation. • This weeks aims are: • To introduce Interaction as a concept that links the human and the computer • To begin to consider designing interaction HCI Lecture 4 - 2010/11

  3. Inter - Action • A system is INTERACTIVE if a human user acts with the system in such a way that the system responds in an ACTIVE way depending on the ACT of the human user HCI Lecture 4 - 2010/11

  4. Humans INTERACT with computers in different ways • Touch • Key presses • Touch gestures • Voice • Speech recognition • Actions • Body recognition Increasing complexity HCI Lecture 4 - 2010/11

  5. Multi-Modal Interaction • Is where the user can interact using more than one mode – a classic example is the combination of speech and touch – key pressing and talking at the same time • Example • Designing multi-modal interaction is difficult as there are ‘mode’ errors HCI Lecture 4 - 2010/11

  6. Mode Errors • Where the computer (and the user) are not sure what ‘mode’ a system is in • Example – the pen as a writing device in a tablet system and the pen as a pointing device (opening up menus) in the same system • Save in speech recognition whilst doing word processing HCI Lecture 4 - 2010/11

  7. Interaction is complex • Norman’s model • Goals: What we want to happen • Execution: Execute action in the world • World: Manipulate objects • Evaluate: validate action and compare results with our goal Goal Execution Evaluation World HCI Lecture 4 - 2010/11

  8. Norman’s model • Execution • Interaction • Task sequence • Physical Action • Evaluation • See • Evaluate • Check HCI Lecture 4 - 2010/11

  9. Execution • Forming the Intention • Goals must be transformed into intentions, i.e.,  specific statements of what has to be done to satisfy the goal.  E.g., "Make a cup of tea using a Tetley tea bag." • Specifying an Action Sequence • What is to be done to the World.  The precise sequence of operators that must be performed to effect the intention.  E.g., “Boil the kettle....." • Executing an Action • Actually doing something.  Putting the action sequence into effect on the world.  E.g., actually boiling the kettle. HCI Lecture 4 - 2010/11

  10. Evaluation • Perceiving the State of the World • Perceiving what has actually happened.  E.g., the experience of taste of the tea. • Interpreting the State of the World • Trying to make sense of the perceptions available.  E.g., Putting those perceptions together to present the sensory experience of a cup of tea. • Evaluating the Outcome • Comparing what happened with what was wanted.  E.g., did the cup of tea match up to the requirement of 'a nice drink'? HCI Lecture 4 - 2010/11

  11. Gulf’s of Interaction • Norman talks about 2 • THE GULF OF EXECUTION:  does the system provide actions that correspond to the intentions of the user? • THE GULF OF EVALUATION:  does the system provide a physical representation that can be directly perceived and that is directly interpretable in terms of the intentions and expectations of the user? • We don’t know what to do • What we do doesn’t take us towards our goal • We don’t see any feedback • The feedback we get doesn’t tell us we are making progress HCI Lecture 4 - 2010/11

  12. Examples… HCI Lecture 4 - 2010/11

  13. Example 2 • The problem statement is clear, but the supplemental explanation is Martian.

  14. Interaction is about Goals • Understand the person => Understand the goals => Understand the interaction HCI Lecture 4 - 2010/11

  15. Keyboards and Keypads • Primary mode of text entry • Beginners 1 keystroke per second • Average office worker 5 strokes per second (50 words a minute) • Rapid data entry can be achieve if more than one key can be pressed simultaneously • Can represent entire words • Court rooms (300 words a minute)

  16. Interacting with computers • Interact with computers in a variety of different ways • Today we will focus on keyboard and pointing devices

  17. Keyboard Layout • QWERTY Keyboard Christopher Latham in the 1870’s to prevent keys getting jammed • Used letter pairs far apart thereby increasing finger travel distance • Keyboards on Computers are thus inefficient

  18. Keyboard Layout • DVORAK increase typing from 150 words per minute to 200 for advanced users plus reduce errors • ABCDE in alphabetical order, novices will find keys

  19. Fitts Law • Calculate effectiveness of interaction • Word Example

  20. Keys • Concave surface and matte finish reduce finger slip • Key presses requires 40- to 125- gram force and displacement from 1 to 4 millimeters • FORCE is important • Key pressed enough emits a light click. This tactile and audible feedback is important • Clicks on surface computing important as you do not have tactile feedback

  21. Keys mobile device • Some come with full QWERTY keyboard • Can reach input of 60 words per minute with both thumbs when auto corrects • Numerical keyboards • Multitap key pressed multiple times and pause • Predictive techniques T9 dictionary based • LetterWise uses probabilities of prefixes for example if type th probability e next letter MacKenzie, I. S., Kober, H., Smith, D., Jones, T., Skepner, E. (2001). LetterWise: Prefix-based disambiguation for mobile text input. Proceedings of the ACM Symposium on User Interface Software and Technology - UIST 2001, pp. 111-120. New York: ACM

  22. Pointing Devices • Useful for 7 types of interaction (Foley et al 1984) • Select - from a menu • Position - drag picture next to text • Orient - a picture, create motion • Path - create a curve • Quantify – specify numeric value e.g. volume in music • Gestures – indicate an action to perform • Text – enter, edit, move

  23. Pointing Devices • Grouped into: • Direct Control • Indirect Control • Direct Control of on screen surface such as touchscreen or stylus • Indirect Control away from the screen mouse, graphics tablets etc..

  24. Stylus • Drawing • Handwrite on touch sensitive device • Natural way to interact • Device needs training to recognise hand writing • Recently had Vision Objects collecting samples of hand writing

  25. iPhone vs Wii – text input • Which is faster for text input?

  26. iPhone vs Wii – text input • iPhone 18.5 wpm • Wii 9.2 wpm • However – error rates • 7.7% for the iPhone • 2.8% for Wii • Errors on the iPhone predominantly cause hitting the adjacent key

  27. Summary • Understanding how users interact is imporatnt • Explored different forms of intearction • Keyboard • Pointing

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