HUMAN COMPUTER INTERACTION Summary By Prof. Dr. Sajjad Mohsin

HUMAN COMPUTER INTERACTION

SummaryByProf. Dr. Sajjad Mohsin

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We have Covered! In HCI, we have covered,

The humanThe computerThe interactionParadigms

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We have Covered!

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

Overview: Map of Human Computer Interaction

Input and Output Devices

Dialogue Techniques

Dialogue Genre

Application Areas

Ergonomics

Evaluation Techniques

Design Approaches

Implementation Techniques and Tools

Example Systems and Case Studies

Human

Language, Communication and Interaction

Human Information Processing

Use and Context

Human-Machine Fit and AdaptationSocial Organization and Work

ComputerComputer Graphics

Dialogue Architecture

Development Process

A a

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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 channelauditory channelHaptic channelmovement

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The Human Information is stored in memory:

sensory memoryshort-term (working) memory long-term memory

Information is processed and applied: reasoningproblem solvingskill acquisitionerror

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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 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 displayssound, smell and haptic feedbacksensors for nearly everything including

movement, temperature, bio-signs 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 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 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 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 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 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 These systems may, for example, use:

speechnon-speech sound touchhandwritinggestures.

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Universal Design Universal design means designing for

diversity, including: people with sensory, physical or cognitive

impairmentpeople of different agespeople 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 unobtrusiveaccurate and robustconsistent and flexible.

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User Support User support comes in a number of styles:

command-based methodscontext-sensitive help tutorial helponline documentationwizards and assistantsadaptive 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 worknot 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 multi-

user, interact with the work-groups and organizations in which they are used.

We need to understand normal human-human communication: face-to-face communication involves eyes,

face and bodyconversation 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 utterancesslower 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 environmentexperiments 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 Sources of information:

existing documentationobservation interviews.

Using task analysis to design: manuals and documentationnew systems.

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Dialogue Notations and Design Dialog is the syntactic level of human-

computer 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 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 itreachability 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 iconphysical 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 statusembodies naïve psychologyhighlights 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 tasksmodeling artifactsplaceholders 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 modelsnew design methodsnew 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

wrongbecause 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 realityaugmented reality information visualization.

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hypertext, multimedia and the world-wide 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