Lecture 5
THE INTERACTION
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Today’s Outline
We will cover today,
Interaction models
translations between user and system
ergonomics
physical characteristics of interaction
What is interaction?
communication
user system
but is that all … ?
Different types of interaction
Models of interaction
Terms of interaction
Norman model
Interaction framework
Terms of interaction
Traditionally, the purpose of an interactive
system is to aid a user in accomplishing
goals from some application domain.
Tasks are operations to manipulate the
concept of domain.
Some terms of interaction
Domain – the area of work under study
e.g. graphic design
Goal – what you want to achieve
e.g. create a solid red triangle
Task – how you go about doing it
– ultimately in terms of operations or actions
e.g. … select fill tool, click over triangle
Note …
traditional interaction …
use of terms differs a lot especially task/goal !!!
Domain or Problem Domain
A problem domain is the area of expertise or
application that needs to be examined to solve a
problem.
A problem domain is simply looking at only the topics of
an individual's interest, and excluding everything else.
For example, when developing a system to measure good
practice in medicine, carpet drawings at hospitals would not be
included in the problem domain. In this example the domain
refers to relevant topics solely within the delimited area of
interest: medicine.
Goal
A goal is a desired result a person or a
system envisions, plans and commits to
achieve a personal or organizational
desired end-point in some sort of assumed
development.
Many people endeavor to reach goals
within a finite time by setting
deadlines.
Task
A task is an activity that needs to be
accomplished within a defined period of time or
by a deadline to work towards work-related
goals.
A task can be broken down into assignments
which should also have a defined start and end
date or a deadline for completion.
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
Norman’s model concentrates on user’s view of the
interface
execution/evaluation loop
goal
execution evaluation
system
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
execution/evaluation loop
goal
execution evaluation
system
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
execution/evaluation loop
goal
execution evaluation
system
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
execution/evaluation loop
goal
execution evaluation
system
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
Using Norman’s model
Some systems are harder to use than others
Gulf of Execution
user’s formulation of actions
≠ actions 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 action
incorrect action
mistake
may not even have right goal!
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 O
output
input
system S U
output core task
I
each has its own unique language input
interaction translation between languages
problems in interaction = problems in translation
Using Abowd & Beale’s model
user intentions
translated into actions at the interface
translated into alterations of system state
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
physical aspects of interfaces
industrial interfaces
What is Ergonomics?
“The scientific discipline concerned with understanding of
interactions among humans and other elements of a system,
and the profession that applies theory, principles, methods
and data to design in order to optimize human well-being and
overall system performance”.
Ergonomics means
“fitting the job to the worker”
From the Greek
Ergo = Work
Nomos = Laws
Source : International Ergonomics Association (IEA) in 2000
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What are Work Related Musculo-Skeletal
Disorders (WMSDs)?
WMSDs are also known as:
Cumulative Trauma Disorders (CTDs)
Repetitive Strain Injuries (RSIs)
Overuse injuries
They are soft tissue injuries which occur
gradually
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What are some of the symptoms of
WMSDs?
Discomfort • Burning
Pain • Swelling
Numbness(lack of sensation) • Change in color
Tingling(pins and needles) • Tightness, loss of
flexibility
Inflammation
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What causes WMSDs?
Heavy, Frequent, or Awkward Lifting
Pushing, Pulling or Carrying Loads
Working in Awkward Postures
Hand Intensive Work
Vibration
Contact Stress
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Risk Factors
Risk of injury depends upon:
Duration of exposure
Frequency of exposure
Intensity of exposure
Combinations of risk factors
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Ergonomics – examples
arrangement of controls and displays
e.g. controls grouped according to function or frequency of use,
or sequentially
surrounding environment
e.g. seating arrangements adaptable to cope with all sizes of user
health issues
e.g. physical position, environmental conditions (temperature,
humidity), lighting, noise,
use of colour
e.g. use of red for warning, green for okay,
awareness of colour-blindness etc.
VIDEO on Ergonomics
Industrial interfaces
Office interface vs. industrial interface?
Context matters!
office industrial
type of data textual numeric
rate of change slow fast
environment clean dirty
… the oil soaked mouse!
Glass interfaces ?
industrial interface:
traditional … dials and knobs
now … screens and keypads
glass interface
+ cheaper, more flexible,
multiple representations,
precise values Vessel B Temp
not physically located, 0 100 200
loss of context,
complex interfaces 113
may need both
multiple representations
of same information
Indirect manipulation
office– direct manipulation
user interacts
with artificial world system
industrial – indirect manipulation
user interacts
with real world
through interface
interface plant
issues ..
feedback immediate
feedback
delays
instruments
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 for expert users than novices
offers direct access to system functionality
command names/abbreviations should be meaningful!
Typical example: the Unix system
Menus
Set of options displayed on the screen
Options visible
less recall - easier to use
rely on recognition so names should be meaningful
Selection by:
numbers, letters, arrow keys, mouse
combination (e.g. mouse plus accelerators)
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 (e.g. SQL)
used to retrieve information from database
requires understanding of database structure and language
syntax, hence requires some expertise
Form-fills
Primarily for data entry or data retrieval
Screen like paper form.
Data put in relevant place
Requires
good design
obvious correction
facilities
Spreadsheets
first spreadsheet VISICALC, followed by
Lotus 1-2-3
MS Excel most common today
sophisticated variation of form-filling.
gridof cells contain a value or a formula
formula can involve values of other cells
e.g. sum of all cells in this column
user
can enter and alter data spreadsheet
maintains consistency
WIMP Interface
Windows
Icons
Menus
Pointers
… or windows, icons, mice, and pull-down menus!
default style for majority of interactive computer
systems, especially PCs and desktop machines
Point and click interfaces
used in ..
multimedia
web browsers
hypertext
just click something!
icons, text links or location on map
minimal typing
Three dimensional interfaces
virtual reality
‘ordinary’ window systems
highlighting
visual affordance flat buttons …
indiscriminate use
just confusing!
click me!
3D workspaces
use for extra virtual space … or sculptured
light and occlusion give depth
distance effects
Three dimensional Work Space
Elements of the wimp interface
windows, icons, menus, pointers
+++
buttons, toolbars,
palettes, dialog boxes
Windows
Areas of the screen that behave as if they were
independent
can contain text or graphics
can be moved or resized
can overlap and obscure each other, or can be laid out next to
one another (tiled)
Windows
scrollbars
allow the user to move the contents of the window up and down
or from side to side
title bars
describe the name of the window
Icons
small picture or image
represents some object in the interface
often a window or action
windows can be closed down (iconised)
smallrepresentation for many accessible
windows
icons can be many and various
highly stylized
realistic representations.
icons
Pointers
important component
WIMP style relies on pointing and selecting things
uses mouse, trackpad, joystick, trackball, cursor keys or
keyboard shortcuts
wide variety of graphical images
Menus
Choice of operations or services offered on the screen
Required option selected with pointer
File Edit Options Font
Typewriter
Screen
Times
problem – take a lot of screen space
solution – pop-up: menu appears when needed
Kinds of Menus
Menu Bar at top of screen (normally), menu drags down
pull-down menu - mouse hold and drag down menu
drop-down menu - mouse click reveals menu
fall-down menus - mouse just moves over bar!
Contextual menu appears where you are
pop-up menus - actions for selected object
pie menus - arranged in a circle
easier to select item (larger target area)
quicker (same distance to any option)
… but not widely used!
Menus extras
Cascading menus
hierarchical menu structure
menu selection opens new menu
infinitum
Keyboard accelerators
key combinations - same effect as menu item
two kinds
active when menu open – usually first letter
active when menu closed – usually Ctrl + letter
usually different !!!
Menus design issues
which kind to use
what to include in menus at all
words to use (action or description)
how to group items
choice of keyboard accelerators
Buttons
individual and isolated regions within a
display that can be selected to invoke an
action
Special kinds
radiobuttons
– set of mutually exclusive choices
check boxes
– set of non-exclusive choices
Toolbars
long lines of icons …
… but what do they do?
fast access to common actions
often customizable:
choose which toolbars to see
choose what options are on it
Palettes and tear-off menus
Problem
menu not there when you want it
Solution
palettes – little windows of actions
shown/hidden via menu option
e.g. available shapes in drawing package
tear-off and pin-up menus
menu ‘tears off’ to become palette
Dialogue boxes
information windows that pop up to inform
of an important event or request
information.
e.g: when saving a file, a dialogue box is
displayed to allow the user to specify the
filename and location. Once the file is saved,
the box disappears.
Summary
Today we have learnt,
Interaction models
translations between user and system
ergonomics
physical characteristics of interaction
