HCI - Human Computer Interface

The Interation

• Interaction models
• Translation between user and system
• Ergonomics
• Physical characteristics of interaction
• Interaction Styles
• The nature of user/system dialog
• Involves at least two participants
• both complex and very different from each other in the way they communicate and view tasks
• interface must effectively translate between the two to allow successful interaction
• Models
• Help in understanding exactly what is going on in the interaction
• Helps in identifying likely problems
• Provide a framework for comparing different interaction styles
• Provide a framework for considering interaction problems
• Models of interaction
• Terms of interaction
• Norman model
• Interaction framework
• Some terms of interaction
• Domain - the area of work under study etc graphic design
• Goal - What you want to achieve
• Task - How are you going to do it
• Donald Norman's Model
• Seven stages
• 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
• concentrates on user's view of the interface
• Using Norman's model
• Gulf of execution
• user's formulation of actions
• action allowed by the system
• Gulf of evaluation
• user's expectation of changed system state
• actual presentation of this state
• Human error - slips and mistakes
• Slip
• understand system and goal
• correct formulation of actions
• incorrect action
• Mistake
• may not even have right hoal
• Fixing things
• Slip - better interface design
• Mistake - better understanding of system
• Abowd and Beale framework
• extension of norman
• their interaction framework has 4 parts
• user
• input
• system
• output
• each has its own unique language
• interaction -> translation between languages
• problems in interaction = problem in translation
• Using Abowd & Beale's model
• user intentions
• translated into actions at the interface
• translated into alterations of system states
• reflected in the output display
• interpreted by the user
• general framework for understanding interaction
• not restricted to electronic computer systems
• identifies all major components involved in interaction
• allows comparative assessment of systems
• an abstraction
• Ergonomics
• study of the physical characteristics of interaction
• Also known as human factors - but this can also be used in HCI
• Good at defining standards and guidelines for defining the way we design certain aspects of systems
• Examples
• arrangement of controls and displays
• controls grouped according to function or frequency of use, or sequentially
• surrounding environment
• seating arrangements adaptable to cope with all sizes of user
• Health issues
• physical position, environmental conditions (temperature, humidity), lighting, noise
• Use of colour
• use of red for warming, green for okay, awareness of colour-blindness
• Industrial interfaces
• numeric, fast, dirty
• Office interfaces
• textual, slow, clean
• Glass interfaces
• industrial interface
• traditional dials and knobe
• now screens and keypad
• glass interface
• cheap, more flexible, multiple representations, precise values
• not physically located, loss of content, complex interfaces
• may need both
• Indirect manipulation
• office - direct manipulation
• user interacts with artificial world
• industrial - indirect manipulation
• user interacts with real world through interfaces
• issues
• feedback
• delay
• Interaction styles
• dialogue computer and user distinct styles of interaction
• Common interaction styles
• command line interface
• menus
• natural language
• question/answer and query dialogue
• form-fills and spreadsheets
• WIMP
• point and click
• three-dimensional interfaces
• Command line interface
• way of expressing instructions to the computer directly
• function keys single characters short abbreviations, whole words or a combination
• suitable for repetitive tasks
• better ofr expert users than novies
• offers direct access to system functionality
• command names/abbreviations should be meaningful
• etc. Unix System
• Menus
• Set of options displayed on the screen
• option visible
• less recall- easier to use
• rely on recognition so names should be meaningful
• Selection by:
• numbers, letters, arrow keys, mouse
• combinations
• Often options hierarchically grouped
• sensible grouping is needed
• Restricted form of full WIMP system
• Natural language
• Familiar to user
• speech recognition or typed natural language
• Problems
• vague
• ambiguous
• hard to do well
• Solutions
• try to understand a subset
• pick on key words
• Query interfaces
• Question/answer interfaces
• user led through interaction via series of questions
• suitable for novice users but restricted functionality
• often used in information systems
• Query languages
• used to retrieve information from database
• requires understanding of database structure and language syntax, hence requires some expertise
• form-fills
• Spreadsheets
• WIMP(Windows Icons Menus pointers) interface
• Point and click interfaces
• Three dimensional interfaces
• Three Dimensional interfaces
• virtual reality
• ordinary window systems
• 3D workspaces
• Elements of the wimp interface
• windows
• icons
• pointers
• menus
• Buttons
• Toolbars
• Dialogue Boxes