Human Computer Interaction (HCI)
The model human processor
- perceptual processor - cognitive processor - motor processor
Types of menu
- pop up menu - pull down menu - fall down menu - pin up menu
Usability Principles (Learnability)
- predictability - synthesisability - familiarity - consistency - generalizability
Interface Design
- principles - guidelines - standards
Multi-Modal Technology
- sight - sound - touch - taste - smell
Alternative mode of HCI
- sound in the interface - touch in the interface - handwriting recognition - gesture recognition
2. Enable frequent users to use shortcuts
abbreviations, function keys, hidden commands, and macro facilities are very helpful to an expert user
definition Usability Principles (Flexibility : Substitutivity)
allowing equivalent values of input and output to be substituted for each other
definition QOC (options)
alternative answers
definition Usability Principles (Learnability : Generalizability)
extending specific interaction knowledge to new situations
definition Usability Principles (Robustness : Responsiveness)
feedback should be commensurate with action
3. Offer informative feedback
for every operator action, there should be some system feedback.
definition Usability Principles (Flexibility : Task migratability)
how easily functions can be moved between user and system
1. Strive for consistency
identical terminology should be used in prompts, menus, and help screens; and consistent commands
definition Sound in the interface
important contributor to usability
definition Design rationale
information that explains why a computer system is the way it is
definition Usability Principles (Flexibility : Customisability)
interface can be adapted to suit different needs
definition Usability Principles (Learnability : Consistency)
likeness in input/output behaviour arising from similar situations or task objectives
definition QOC (question)
major issues of a design
definition Usability Principles (Learnability : Familiarity)
matching user's expectations
definition QOC (criteria)
means to assess options
definition Tolerance for error
minimizing the impact and damage caused by mistakes or unintended behavior
definition Handwriting Recognition
natural form of communication
definition Ergonomics
physical characteristics of interaction
definition Process-oriented
preserves order of deliberation and decision making
Types of design rationale
process-oriented, structure-oriented
waterfall model with feedback
requirements specification > architectural design > detailed design > coding and unit testing > integration and testing > operation and maintenance
definition Touch in the interface
sense that can be used to both send and receive
definition Usability Principles (Robustness : Recoverability)
support for undoing errors
definition Usability Principles (Flexibility : Multi-threading)
support simultaneous tasks
definition Laboratory Studies
users are take out of their normal work environment to take part in controlled tests, often in a specialist usability laboratory
definition Usability Principles (Flexibility : Dialogue initiative)
who controls dialogue flow
Usability Principles (Flexibility)
- Dialogue initiative - multi-threading - task migratability - substitutivity - customisability
Goals of Evaluation
- assess extent of system functionality - assess effect of interface on user - identify specific problems
types of slips
- capture error - description error - loss of activation - mode errors
Evaluating Designs
- cognitive walkthrough - heuristic evaluation - review-based evaluation - model-based evaluation
Interface Style
- command line interface - menus - natural language - question/answer and query dialogue - form-fills and spreadsheets - WIMP - point and click - three-dimensional interfaces
Usability Components
- efficiency - learnability - errors - satisfaction - memorability
Seven Principles of universal design of interactive system
- equitable use - flexibility in use - simple and intuitive to use - perceptible information - tolerance for error - low physical effort - size and space for approach and use
Generic System response for errors
- general idea : forcing functions - gag - warn - do nothing - self correct - lets talk about it - teach me
GOMS
- goals - operator - methods - selection
Cognitive Walkthrough (Comparison Heuristic Evaluation)
- informed by cognitive psychology - done by one person - more formal - better for highly structured tasks
Heuristic Evaluation (Comparison Cognitive Walkthrough)
- informed by design practices - done by appointed experts - less formal - better for less structured task
Query Techniques
- interviews - questionnaires
Styles Of Evaluation
- laboratory studies - field studies
Usability Principles
- learnability - flexibility - robustness
Errors we make
- mistakes - slips
Usability Principles (robustness)
- observability - recoverability - responsiveness - task conformance
Factors considered in experimental design
- participants - variables - hypotheses - experimental design - statistical measures
Schnederman's Eight Golden Rules
- strive for consistency - enable frequent users to use shortcuts - offer informative feedback - design dialogs to yield closure - offer error prevention and simple error handling - permit easy reversal of actions - support internal locus of control - reduce short-term memory load
Observational Methods
- think aloud - cooperative evaluation - protocol analysis - automated analysis - post task walkthrough
Types of help
- tutorial - reference manuals - reminders
Model Of Interaction - Norman's execution - evaluation cycle
- user establishes the goal - formulates intention - specifies actions at interface - executes action - perceives system state - interprets system state - evaluates system state with respect to goal
definition Gesture Recognition
being able to control the computer with certain movement of the hand
definition Usability Principles (Learnability : Synthesisability)
can assess effect of past actions
definition Interaction Design
creating interventions in often complex situations using technology of many kinds including pc, software, the web and physical devices
definition Usability Principles (Robustness : Task conformance)
degree to which the system supports the user's tasks
definition Perceptible information
design should provide effective communication of information regardless of the environmental condition or the user's abilities
5. Offer simple error handling
design the system so the user cannot make a serious error
7. Support internal locus of control
design the system to make users the initiators of actions rather than the responders
definition Low physical effort
design to be comfortable to use, minimizing physical effort and fatigue
definition Usability Principles (Learnability : predictability)
determinism and operation visibility
definition Human Computer Interaction (HCI)
discipline concerned with the design, evaluation and implementation of interactive computing systems for human use and with the study of major phenomena surrounding them
definition Structure-oriented
emphasizes post hoc structuring of considered design alternatives
definition Usability
the capability of the software product to be understood, learned, used and attractive to the user, when used under specified conditions
definition Flexibility in use
the design allows for range of ability and preference, through choice of methods of use and adaptively to the user's pace, precision and custo
definition Equitable use
the design is useful to people with range of ability and appealing to all
definition Field Studies
the designer of evaluator out into the user's work environment in order to observe the system in action
4. Design dialog to yield closure
the informative feedback at the completion of a group of actions gives the operators the satisfaction
8. Reduce short-term memory load
the limitation of human information processing in short-term memory requires that displays be kept simple
definition Interaction Styles
the nature of user/system dialog
definition Size and space for approach and use
the placement of the system should be such that it can be reached and used by any user regardless of body size, posture and mobility
6. Permit easy reversal of actions
this feature relieves anxiety, since the user knows that errors can be undone
definition Simple and intuitive to use
to use regardless of knowledge, experience, language or level of concentration of the user
definition Interactions models
translations between user and system
definition Usability Principles (Robustness : Observability)
user impression of system state
