Chapter 26 Flashcards
PoHCI, week 3 (28 cards)
What is an interaction technique?
An interaction technique is a computation that couples input and output, to support elementary interactive tasks
Name some elementary interaction tasks
Moving the active area or cursor in the user interface (pointing techniques)
Selecting or manipulating an object (menu techniques)
Entering numbers and text (text entry techniques)
Changing which part of an information space the user sees (camera control / navigation techniques)
What are the four essential interaction techniques?
Pointing techniques
Menu techniques
Text entry techniques
Camera control / Navigation techniques
What are the common design objectives considered for interaction techniques?
Performance - Speed and accuracy in representative tasks
Experience - Self reported experience of flow, mastery, control, or similar quality
Learnability - Rate of learning; Time it takes to achiece a desired level of skill
Mobility - Suitability for conditions in which users are walking, multitasking, or otherwise encumbered
Ergonomics - Physiological and experienced comfort in representative tasks
Accesibility - Suitability for users with different abilities
What is baseline design?
Previously known state-of-the-art techniques or designs popular in everyday use
Compare performance achieved in own design to baseline design
What is gaze-based interaction and the Midas effect?
A class of interaction techniques developed primarily for users with severe motor disabilities, for
example dwell-based selection: A target can be selected by ficating on it for long enough
Midas effect: Gazing at something may inadvertently select it
What is a pointing facilitation technique?
It maps changes registered in an input device to the movement of a cursor or the presentation of
potential targets on display
What is input transfer functions?
Techniques that map changes in input signal to cursor movement
Example: Control-to-display (gain) function (CD function)
What is display transfer functions?
Techniques that change the presentation of potential targets to facilitate their selection
Example: BubbleCursor
What is a CD gain function?
Input transfer functions used in indirect input devices
Maps changes in control space (e.g. touchpad) to changes in display space (e.g. visible cursor)
vout = fCD(vin) × vin
What does selection and manipulation techniques do?
They affect an object once it has been identified, for instance through pointing
What is simple selection?
You click the mouse over an object or tap it with your finger. The selection is assumed to be binary -
either you select an object, or you do not select it
What is menu selection?
An interactive menu system organizes a collection of items on display so that the user can explore the
menu and select the desired items. They often use hierarchical organization, where items are placed
under submenus
What is a pie menu?
Presents menu as a circle subdivided into circular sectors associated with commands or further menu
structures
What is a marking menu?
A refinement of a pie menu that supports a continuous transition from novice to expert behavior. It
couples an incremental angular 2D single-stroke gesture recognizer with a pie menu
What does text entry techniques do?
They use computational methods to facilitate the task of entering text
Goal is to make text entry more efficient, less effortful, or enable it in circumstances it would not
normally be possible
Explain different ways to support text entry
Correcting and completing phrases (e.g. auto-completion)
Offering an alternative units of entry (units could be character, syllable, word and phrase)
Multimodal and cross-modal entry (using voice, eye movements etc)
What is camera control?
Helps to change what is shown on the display / move the point-of-view
Example: Panning and zooming
Explain desert fog
The situation where you need to reach a target but has no navigational cues where it is
What are integral interaction techniques
When both actions can be done at the same time
Example: Being able to pan and zoom at the same time
What is control theory used for?
Illuminating the dynamic relationships that input actions and events on display have, and what the
consequent challenges are to the user
What are some elements in an analysis of control?
Goal: The user has a goal in mind, a state that the computer should be driven to, such as selecting a
particular target on display
Feedforward: The user sends a control signal via the input sensor to change the state
Transfer function: A program that maps changes in the feedforward signal to changes on the display
Feedback: The state-change is now visible on display
Comparator: The feedback is compared against the goal state in order to determine the new feedforward signal
What does the theory of internal models in motor control state`
Controlling an interaction technique requires prediction. Its learning can be thought as a form of
function learning.
What is the performance dip in learning?
When a new technique is introduced, an immediate cost ensures.
Changing from one technique to use another one introduces a learning cost
