HCI 3RD CHAPTER

interaction models

translations between user and system •

ergonomics

physical characteristics of interaction •

interaction styles

the nature of user/system dialog •

context

social, organizational, motivational

Interaction

involves at least two participants: the user and the system

domain

the area of work under study

task

how you go about doing it

goal

what you want to achieve

Intention

Is a specific action required to meet the goal

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

gulf of execution

is the difference between the user’s formulation of the actions to reach the goal and the actions allowed by the system.)

Abowd and Beale framework

has 4 parts – user – input – system – output

Ergonomics

Study of the physical characteristics of interaction

Ergonomics - examples

• arrangement of controls and displays

surrounding environment

• health issues

• use of colour

industrial interface

traditional … dials and knobs – now … screens and keypads

glass interface

cheaper, more flexible, multiple representations, precise values

Command line interface

Way of expressing instructions to the computer directly

Menus

Set of options displayed on the screen

Natural language

Familiar to user • speech recognition or typed natural language

Query interfaces

Question/answer interfaces

Form-fills

Primarily for data entry or data retrieval

Spreadsheets

sophisticated variation of form-filling. – grid of cells contain a value or a formula

WIMP Interface

default style for majority of interactive computer systems, especially PCs and desktop machines

Windows

Areas of the screen that behave as if they were independent

Icons

small picture or image • represents some object in the interface

Pointers

important component, uses mouse, trackpad, joystick, trackball, cursor keys or keyboard shortcuts

Menus

Choice of operations or services offered on the screen

Contextual menu

appears where you are

pop-up menus

actions for selected object

pie menus

arranged in a circle

hierarchical menu structure

menu selection opens new menu

key combinations

same effect as menu item

Buttons

individual and isolated regions within a display that can be selected to invoke an action

Toolbars

long lines of icons, fast access to common actions

palettes

little windows of actions

Dialogue boxes

information windows that pop up to inform of an important event or request information.

Context

Interaction affected by social and organizational context

Norman’s model

concentrates on user’s view of the interface

slip

better interface design

mistake

better understanding of system

slip

understand system and goal, correct formulation of action

interaction

translation between languages

true

controls grouped according to function or frequency of use, or sequentially

direct manipulation

user interacts with artificial world

indirect manipulation

user interacts with real world through interface

Query languages

used to retrieve information from database

Point and click interfaces

used in .. – multimedia – web browsers – hypertext

Three dimensional interfaces

virtual reality, ordinary’ window systems, 3D workspaces

Keyboard accelerators

key combinations - same effect as menu item

tear-off and pin-up menus

menu ‘tears off’ to become palette

spring back controls

one-shot buttons, joystick

gulf of evaluation

is the distance between the physical presentation of the system state and the expectation of the user

Keyboard accelerators

key combinations - same effect as menu item

Cascading menus

hierarchical menu structure – menu selection opens new menu – and so in ad infinitum