Transcript Chapter2 GUI - WordPress.com

DDPC 1633/DDC 3153
Human-Computer Interaction/
User Interface Programming
Chapter 2
Making interactive systems feel
natural for users
At the end of this lecture
you should be able to …
1. Define what natural computing is and
explain the main principles of natural
computing
2. Explain the key concepts of user-centred
system design (UCSD)
3. Explain what interactive design is
1. Natural computing
The study of
(i) how people process and store information,
(ii) manipulate symbols,
(iii)ascribe personal values to events,
(iv)attribute cultural and emotive judgements and
(v) use interactive artefacts to enhance our
lifestyles
Natural computing
• Natural computing is not the same as saying the human
brain is a computer. The human brain is MUCH more.
• Information processing is just one of the capabilities of
the human brain. The main idea of natural computing is
that information processing is a natural process for us.
– The user perspective
• Provide conceptual framework for user modelling
– The designer's perspective
• Will provide better understanding of designs that will support users
– The sustainability perspective
• Need for well-designed systems is a necessity, not a luxury
2. Key features of usercentred system design
• A central focus on the people who will use the
systems, on their preferences and requirements
• Building simple models of the users, the tasks and
the technological systems
• An iterative process
• Prototyping and the evaluation of alternatives by
users.
– Designers have vast number of key decisions to make
– Designers work with their own ‘mental model’ – can
become subjective
UCSD
Problem
statement
Observation of
existing systems
Task analysis
HTA
Usability guidelines
& heuristics
Technical & legal etc.
constraints
Requirements
gathering
Requirement statement
Design and
storyboarding
Storyboard
Prototype
implementation
Functional
Non-functional
Prototype
Evaluation
Transcript &
evaluation report
Installation
Final
implementation
The user or users
• What do you think of when you read the
phrase 'the user'? Do you think of:
– Someone like yourself?
– A stereotype 'user'?
– A group of 'typical users'?
– You picture individuals, each with different
skills and preferences, different priorities and
objectives?
• Rather use ‘users’ – not one typical user
Is UCSD sufficient?
UCSD may not be enough – it may be impossible to
capture needs/preferences of all users in 1 design
People may need the additional facility to:
• Customise a system
• Add assistive technology for extreme
circumstances or disability
• Have adaptable systems that respond to the
ways in which they are used or to a user's
known profile (personalisation)
Six elements of
natural computing
• Natural computing
– A research and application area that draws
from cognitive science, cognitive psychology,
HCI, interaction design, sociology and
anthropology
• What can users do?
– People drive technology to achieve objectives,
not the other way round
• Modelling users
• Understanding the domain – wide diversity of disciplines
• Understanding human learning
• Meaning as a basis for practical action
– links between theory & practice
Core concepts
These are common to both natural computing
and user-centred system design
1.
2.
3.
4.
5.
6.
User model
Universal access
Design for all
Inclusive design
Task models
Technological platform
1. User model
• Vary from:
– Simple list of preferences to
– Psychological profile
• Strengths and weaknesses, skills, interests,
potential, disabilities, age, culture, experience.
• The more complete the model
– the better it can be used in system design, but
– the more expensive it is in terms of time,
expertise and money to develop it.
• Don’t think of the typical user only – also include
the diversity and complexity of user population
2. Universal access
Universal access is the objective of
making systems that are accessible:
– anytime,
– anywhere and
– to anyone
of the intended user population.
3. Design for all
It is similar to 'universal access', but also
promotes the notion of:
– careful design and design standards,
so that users with special needs are not
excluded from the use of a system.
4. Inclusive design
• Universal access and design for all are
essentially qualitative
• Inclusive design is a quantitative measure
by which designers can calculate the
numbers of users who are excluded by
specific design features (based on abilities
of users)
• Understanding and quantifying the
consequences of different design options
for diverse range of potential users
5. Task models
• Output of task analysis
• You must identify the key features of the
task to be achieved
– and recognise those aspects that must
or can be changed.
6. Technological platform
In the earlier days of system design
– technology placed severe restrictions on
the functionality of proposed systems
These days
– technological options are less restrictive
and, we can expect our expectations to
be fulfilled by the technology
Interactive design
• UCSD is an interactive and iterative process
– Designer and design process work interactively
– Emphasis on research, design and evaluation in cycle
– Initial good ideas are iteratively revised in the light of experience and
evaluation
• Main stages of UCSD (refer to figure 2.1)
–
–
–
–
Task analysis
Requirements specification
Prototyping
Evaluation
• Creation and reconciliation of three elements
– User model
– Task model
– Technology model
Strengths and weaknesses
of interactive systems
– Modern interactive systems can be powerful
because they draw on powerful technology
• If power is not utilised = weakness
– Interactive systems may provide useful
functions
• Lack of usefulness = weakness
– Interactive systems differ in the extent that
they are usable
• Lack of usability = weakness
– Accessibility varies between good and
poorly designed systems
• Poor accessibility = weakness
Summary…
Natural computing provides a basis to begin
to understand people and systems, and how
people might use technology to good effect
Exercise
• What is UCSD?
• What is natural computing?
• What are six elements of natural
computing?
• What are the properties of an interactive
system that make it easy to use?