HUMAN COMPUTER
INTERACTION
Summary
By
Prof. Dr. Sajjad Mohsin
We have Covered!

In HCI, we have covered,
 The
human
 The computer
 The interaction
 Paradigms
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We have Covered!


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
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Interaction design basics
HCI in the software process
Design rules
Implementation support
Evaluation techniques
Universal design
User support
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We have Covered!
Cognitive models
 Socio-organizational issues and
stakeholder requirements
 Communication and collaboration
models
 Task analysis
 Dialogue notations and design
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We have Covered!
Models of the system
 Modeling rich interaction
 Groupware
 Ubiquitous computing and
augmented realities
 Hypertext, multimedia, and the
world wide web
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Overview: Map of Human Computer Interaction
Use and Context
Social Organization and Work
Human-Machine Fit and Adaptation
Application Areas
Human
Computer
Dialogue
Techniques
Human
Information
Processing
Language,
Communication
and Interaction
Evaluation
Techniques
Computer
Graphics
Aa
Ergonomics
Dialogue
Genre
Input and
Output Devices
Example Systems
and Case Studies
Design
Approaches
Development Process
Dialogue
Architecture
Implementation
Techniques and Tools
The Human
Humans are limited in their capacity to
process information. This has important
implications for design.
 Information is received and responses
given via a number of input and output
channels:

 visual
channel
 auditory channel
 Haptic channel
 movement
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The Human

Information is stored in memory:
 sensory
memory
 short-term (working) memory
 long-term memory

Information is processed and applied:
 reasoning
 problem
solving
 skill acquisition
 error
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The Human
Emotion influences human capabilities.
 Users share common capabilities but are
individuals with differences, which should
not be ignored.
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The Computer

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A computer system comprises various elements,
each of which affects the user of the system.
Input devices for interactive use, allowing text
entry, drawing and selection from the screen:
 text
entry: traditional keyboard, phone text entry,
speech and handwriting
 pointing: principally the mouse, but also touchpad,
stylus, and others
 3D interaction devices
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The Computer

Output display devices for interactive use:
 different
types of screen mostly using some
form of bitmap display
 large displays and situated displays for
shared and public use
 digital paper may be usable in the near future

Virtual reality systems and 3D visualization
have special interaction and display
devices.
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The Computer

Various devices in the physical world:
 physical
controls and dedicated displays
 sound, smell and haptic feedback
 sensors for nearly everything including
movement, temperature, bio-signs
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Paper output and input: the paperless
office and the less-paper office:
 different
types of printers and their
characteristics, character styles and fonts
 scanners and optical character recognition
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The Computer

Memory:
 short-term
memory: RAM
 long-term memory: magnetic and optical disks
 capacity limitations related to document and
video storage
 access methods as they limit or help the user
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The Computer

Processing:
 the
effects when systems run too slow or too
fast, the myth of the infinitely fast machine
 limitations on processing speed
 networks and their impact on system
performance.
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The Interaction
Interaction models help us to understand
what is going on in the interaction between
user and system. They address the
translations between what the user wants
and what the system does.
 Ergonomics looks at the physical
characteristics of the interaction and how
these influence its effectiveness.

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The Interaction
The dialog between user and system is
influenced by the style of the interface.
 The interaction takes place within a social
and organizational context that affects
both user and system.
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Paradigms
Examples of effective strategies for
building interactive systems provide
paradigms for designing usable interactive
systems.
 The evolution of these usability paradigms
also provides a good perspective on the
history of interactive computing.
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Paradigms
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These paradigms range from the
introduction of time-sharing computers,
through the WIMP and web, to ubiquitous
and context-aware computing
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Design Process
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Interaction Design Basics

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Interaction design is about creating interventions
in often complex situations using technology of
many kinds including PC software, the web and
physical devices
Design involves:
 achieving
goals within constraints and trade-off
between these
 understanding the raw materials: computer and
human
 accepting limitations of humans and of design
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Interaction Design Basics
The design process has several stages
and is iterative and never complete.
 Interaction starts with getting to know the
users and their context: finding out who
they are and what they are like ... probably
not like you!
 Talking to them, watching them
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Interaction Design Basics
Scenarios are rich design stories, which
can be used and reused throughout
design: they help us see what users will
want to do
 they give a step-by-step walkthrough of
users' interactions: including what they
see, do and are thinking
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Interaction Design Basics
Users need to find their way around a
system; this involves: helping users know
where they are, where they have been and
what they can do next
 Creating overall structures that are easy to
understand and fit the users' needs
 Designing comprehensible screens and
control panels

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Interaction Design Basics
Complexity of design means we don't get it
right first time: so we need iteration and
prototypes to try out and evaluate
 But iteration can get trapped in local
maxima, designs that have no simple
improvements, but are not good
 Theory and models can help give good
start points
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HCI in the software process
Software engineering provides a means of
understanding the structure of the design
process, and that process can be
assessed for its effectiveness in interactive
system design.
 Usability engineering promotes the use of
explicit criteria to judge the success of a
product in terms of its usability.
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HCI in the Software Process
Iterative design practices work to
incorporate crucial customer feedback
early in the design process to inform
critical decisions which affect usability.
 Design involves making many decisions
among numerous alternatives. Design
rationale provides an explicit means of
recording those design decisions and the
context in which the decisions were made.
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Design Rules
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Designing for maximum usability is the goal of
interactive systems design.
Abstract principles offer a way of understanding
usability in a more general sense, especially if
we can express them within some coherent
catalog.
Design rules in the form of standards and
guidelines provide direction for design, in both
general and more concrete terms, in order to
enhance the interactive properties of the system.
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Design Rules
The essential characteristics of good
design are often summarized through
'golden rules' or heuristics.
 Design patterns provide a potentially
generative approach to capturing and
reusing design knowledge.
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Implementation Support
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Programming tools for interactive systems
provide a means of effectively translating
abstract designs and usability principles into an
executable form. These tools provide different
levels of services for the programmer.
Windowing systems are a central environment
for both the programmer and user of an
interactive system, allowing a single workstation
to support separate user-system threads of
action simultaneously.
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Implementation Support

Interaction toolkits abstract away from the
physical separation of input and output
devices, allowing the programmer to
describe behaviors of objects at a level
similar to how the user perceives them.
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Implementation Support
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User interface management systems are
the final level of programming support
tools, allowing the designer and
programmer to control the relationship
between the presentation objects of a
toolkit with their functional semantics in the
actual application.
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Evaluation Techniques

Evaluation tests the usability, functionality
and acceptability of an interactive system.
Evaluation may take place:
 in
the laboratory
 in the field.

Some approaches are based on expert
evaluation:
 analytic
methods
 review methods
 model-based methods.
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Evaluation Techniques

Some approaches involve users:
experimental methods
 observational
methods
 query methods.

An evaluation method must be chosen
carefully and must be suitable for the job.
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Universal Design
Universal design is designing systems so
that they can be used by anyone in any
circumstance.
 Multi-modal systems are those that use
more than one human input channel in the
interaction.
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Universal Design
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These systems may, for example, use:
 speech
 non-speech
sound
 touch
 handwriting
 gestures.
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Universal Design

Universal design means designing for
diversity, including:
 people
with sensory, physical or cognitive
impairment
 people of different ages
 people from different cultures and
backgrounds.
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User Support
Users have different requirements for
support at different times.
 User support should be:

 available
but unobtrusive
 accurate and robust
 consistent and flexible.
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User Support

User support comes in a number of styles:
command-based methods
 context-sensitive
help
 tutorial
help
 online documentation
 wizards and assistants
 adaptive help.
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User Support

Design of user support must take account
of:
 presentation
issues
 implementation issues.
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Models and
Theories
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Cognitive Models

Cognitive models represent users of
interactive systems.
 Hierarchical
models represent a user's task
and goal structure.
 Linguistic models represent the user-system
grammar.
 Physical and device models represent human
motor skills.
 Cognitive architectures underlie all of these
cognitive models.
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socio-organizational issues and
stakeholder requirements

There are several organizational issues
that affect the acceptance of technology
by users and that must therefore be
considered in system design:
 systems
may not take into account conflict
and power relationships
 those who benefit may not do the work
 not everyone may use systems.
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socio-organizational issues..
In addition to generic issues, designers
must
identify
specific
stakeholder
requirements within their organizational
context.
 Socio-technical
models capture both
human and technical requirements.
 Soft systems methodology takes a broader
view of human and organizational issues.
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socio-organizational issues..
Participatory design includes the user
directly in the design process.
 Ethnographic methods study users in
context, attempting to take an unbiased
perspective.
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Communication and Collaboration
Models
All computer systems, single user or multiuser, interact with the work-groups and
organizations in which they are used.
 We need to understand normal humanhuman communication:

 face-to-face
communication involves eyes,
face and body
 conversation can be analyzed to establish its
detailed structure.
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Communication and Collaboration
Models

This can then be applied to text-based
conversation,
which
has:
reduced
feedback for confirmation
 less
context to disambiguate utterances
 slower pace of interaction
but is more easily reviewed.
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Communication and Collaboration
Models

Group working is more complex than that
of a single person: it is influenced by the
physical environment
 experiments
are more difficult to control and
record
 field studies must take into account the social
situation.
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Task Analysis
Task analysis is the study of the way
people perform tasks with existing
systems.
 Techniques for task analysis:

 decomposition
of tasks into subtasks
 taxonomic classification of task knowledge
 listing things used and actions performed.
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Task Analysis
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Sources of information:
 existing
documentation
 observation
 interviews.

Using task analysis to design:
 manuals
and documentation
 new systems.
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Dialogue Notations and Design
Dialog is the syntactic level of humancomputer interaction; it is rather like the
script of a play, except the user, and
sometimes the computer, has more
choices.
 Notations used for dialog description can
be:

 diagrammatic:
easy to read at a glance
 textual: easier for formal analysis.
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Dialogue Notations and Design

The dialog is linked:
 to
the semantics of the system, what it does
 to the presentation of the system, how it
looks.

Formal descriptions can be analyzed: for
inconsistent actions
 for
difficult to reverse actions
 for missing items
 for potential miskeying errors.
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Models of the Systems
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We need to know what a system does in order to
assess its usability.
Standard software engineering formalisms can
be used to specify an interactive system. These
are of various types:
 model
based, such as Z, which describe the system's
state and operations
 algebraic formalisms, which describe the effects of
sequences of actions
 temporal and deontic logics, which describe when
things happen and who is responsible.
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Models of the System

Special interaction models are designed
specifically to describe usability properties,
including:
 predictability
and observability - what you can
tell about the system from looking at it
 reachability and undo - what you can do with
it.
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Models of the System

Most formal models and notations focus
on events and changes that happen when
they occur, but we need richer models to
deal with:
 interstitial
behavior - the things that happen
between events such as dragging an icon
 physical objects in ubiquitous computing or
virtual reality
 the tension between precise time and more
fuzzy human ideas of time.
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Modeling Rich Interaction

We operate within an ecology of people,
physical artifacts and electronic systems,
and this rich ecology has recently become
more complex as electronic devices
invade the workplace and our day-to-day
lives. We need methods to deal with these
rich interactions.
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Modeling Rich Interaction

Status-event analysis is a semi-formal,
easy to apply technique that:
 classifies
phenomena as event or status
 embodies naïve psychology
 highlights feedback problems in interfaces.
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Modeling Rich Interaction

Aspects of rich environments can be
incorporated into methods such as task
analysis: other people
 information
requirements
 triggers for tasks
 modeling artifacts
 placeholders in task sequences.
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Modeling Rich Interaction

New sensor-based systems do not require
explicit interaction, this means: new
cognitive and interaction models
 new
design methods
 new system architectures.
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Looking Outside
Box
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Groupware
Groupware is a term for applications
written to support the collaboration of
several users.
 Groupware can support different activities:

 direct
interpersonal communication
 ideas generation and decision making
 sharing computer objects.
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Groupware

It can be classified in several ways:
 by
where and when it happens
 by the sort of information shared
 by the aspects of cooperation's supported.
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Groupware

Implementing groupware is more difficult
than single-user applications:
 because
of network delays
 because there are so many components to go
wrong
 because graphical toolkits assume a single
user.
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Ubiquitous computing and
augmented realities
The traditional computer is a glass box all you can do is press buttons and see the
effect.
 Ubiquitous computing and augmented
reality systems break this glass box by
linking the real world with the electronic
worlds.
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Ubiquitous computing and
augmented realities

Applications include: ubiquitous computing
 virtual
reality
 augmented reality
 information visualization.
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hypertext, multimedia and the worldwide web
Hypertext allows documents to be linked in
a non-linear fashion.
 Multimedia incorporates different media:
sound, images, video.
 The world wide web is a global
hypermedia system.
 Animation and video can show information
that is difficult to convey statically.
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hypertext, multimedia and the
world-wide web
Applications of hypermedia include online
help, education and e-commerce
 Design for the world wide web illustrates
general hypermedia design, but also has
its own special problems.
 Dynamic web content can be used for
simple online demonstration or for
complete
web-based
business
applications.
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THE END
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