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Lesson#15
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INTERACTION PARADIGMS
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As the aim of this lecture is to introduce you the study of
Human Computer
Interaction, so that after studying this you will be able to:
. Describe WIMP interfaces in
detail
. Discuss different
interaction paradigms
We have briefly discussed about the WIMP interfaces in last
lecture. Today we will
discuss WIMP interfaces in detail.
15.1 The WIMP Interfaces
In our last lecture we have already discussed the four key
features of the WIMP
interface that give it its name – windows, icons, pointers and
menus – and today we
will discuss these in greater detail. There are also many
additional interaction objects
and techniques commonly used in WIMP interfaces, some designed
for specific
purposes and others more general. Our discussion will cover the
toolbars, menus,
buttons, palettes and dialog boxes.
Together, these elements of the WIMP interfaces are called
widgets, and they
comprise the toolkit for interaction between user and system.
Windows
Windows are areas of the screen that behave as if they were
independent terminals in
their own right. A window can usually contain text or graphics,
and can be moved or
resized. More than one window can be on a screen at once,
allowing separate tasks to
be visible at the same time. Users can direct their attention to
the different windows as
they switch from one thread of work to another.
If one window overlaps the other, the back window is partially
obscured, and then
refreshed when exposed again. Overlapping windows can cause
problems by
obscuring vital information, so windows may also be tiled, when
they adjoin but do
not overlap each other. Alternatively, windows may be placed in
a cascading fashion,
where each new window is placed slightly to the left and below
the previous window.
In some systems this layout policy is fixed, in others the user
can select it.
Usually windows have various things associated with them that
increase their
usefulness. Scrollbars are one such attachment, allowing the
user to move the contents
of the window up and down, or from side to side. This makes the
window behave as if
it were a real window onto a much larger world, where new
information is brought
into view by manipulating the scrollbars.
There is usually a title bar attached to the top of a window,
identifying it to the user,
and there may be special boxes in the corners of the window to
aid resizing, closing,
or making as large as possible. Each of these can be seen in the
figure.
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In addition, some systems allow windows within windows. For
example, in Microsoft
Office applications, such as Excel and Word, each application
has its own window
and then within this each document has a window. It is often
possible to have
different layout policies within the different application
windows.
Icons
Windows can be closed and lost forever, or they can be shrunk to
some very reduced
representation. A small picture is used to represent a closed
window, and this
representation is known as an icon. By allowing icons, many
windows can be
available on the screen at the same time, ready to be expanded
to their full size by
clicking on the icon. Shrinking a window to its icon is known as
iconifying the
window. When a user temporarily does not want to follow a
particular thread of
dialog, he can suspend that dialog by iconifying the window
containing the dialog.
The icon saves space on the screen and serves as a remainder to
the user that he can
subsequently resume the dialog by opening up the window. Figure
shows a few
examples of icons used in a typical windowing system
(Microsoft).
Icons can also be used to represent other aspects of the system,
such as a wastebasket
for throwing unwanted files into, or various disks, programs or
functions, that are
accessible to the user. Icon can take many forms: they can be
realistic representation
of the objects that they stand for, or they can be highly
stylized. They can even be
arbitrary symbols, but these can be difficult for users to
interpret.
Pointers
The Pointer is an important component of the WIMP interface,
since the interaction
style required by WIMP relies very much on pointing and
selecting things such as
icons. The mouse provides an input device capable of such tasks,
although joysticks
and trackballs are other alternatives. The user is presented
with a cursor on the screen
that is controlled by the input device. A verity of pointer
cursors is shown in figure.
The different shape of cursor are often used to distinguish
modes, for example the
normal pointer cursor maybe an arrow, but change to change to
cross-hairs when
drawing a line. Cursors are also used to tell the user about
system activity, for
example a watch or hourglass cursor may be displayed when the
system s busy
reading a file.
Pointer cursors are like icons, being small bitmap images, but
in addition all cursors
have a hot-spot, the location to which they point.
Menus
The last main feature of the windowing system is the menu, an
interaction technique
that is common across many non-windowing systems as well. A menu
presents a
choice of operations or services that can be performed by the
system at a given time.
As we discussed our ability to recall information is inferior to
our ability to recognize
it from some visual cue. Menus provide information cues in the
form of an ordered
list of operations that can be scanned. This implies that the
names used for the
commands in the menu should be meaningful and informative.
The pointing device is used to indicate the desired option. As
the pointer moves to the
position of a menu item, the item is usually highlighted to
indicate that it is the
potential candidate for selection. Selection usually requires
some additional user
action, such as pressing a button on the mouse that controls the
pointer cursor on the
screen or pressing some special key on the keyboard. Menus are
inefficient when they
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have too many items, and so cascading menus are utilized, in
which item selection
opens up another menu adjacent to the item, allowing refinement
of the selection.
Several layers of cascading menus can be used.
The main menu can be visible to the user all the time, as a menu
bar and submenus
can be pulled down or across from it upon request. Menu bars are
often placed at the
top of the screen or at the top of each window. Alternative
includes menu bars along
one side of the screen, or even placed amongst the windows in
the main ‘desktop’
area. Websites use a variety of menu bar locations, including
top, bottom and either
side of the screen. Alternatively, the main menu can be hidden
and upon request it
will pop up onto the screen. These pop-up menus are often used
to present contextsensitive
options, for example allowing one to examine properties of
particular onscreen
objects. In some systems they are also used to access more
global actions when
the mouse is depressed over the screen background.
Pull-down menus are dragged down from the title at the top of
the screen, by moving
the mouse pointer into the title par area and pressing the
button. Fall-down menus are
similar, except that the menu automatically appears when the
mouse pointer enters the
title bar, without the user having to press the button. Some
menus explicitly asked to
go away. Pop up menus appear when a particular region of the
screen, may be
designated by an icon, is selected, but they only stay as long
as the mouse button is
depressed.
Another approach to menu selection is to arrange the options in
a circular fashion.
The pointer appears in the center of the circle, and so there is
the same distance to
travel to any of the selections. This has the advantages that it
is easier to select items,
since they can each have a larger target area, and that the
selection time for each item
is the same, since the pointer is equidistant from them all.
However, these pie menus
take up more screen space and are therefore less common in
interface.
The major problems with menus in general are deciding what items
to include and
how to group those items. Including too many items makes menus
too long or creates
too many of them, whereas grouping causes problems in that items
that relate to the
same topic need to come under the same heading, yet many items
could be grouped
under more than one heading. In pull-down menus the menu label
should be chosen to
reflect the function of the menu items, and items grouped within
menus by function.
These groupings should be consistent across applications so that
the user can transfer
learning to new applications. Menu items should be ordered in
the menu according to
importance and frequency of use, and appropriate functionalities
should be kept apart
to prevent accidental selection of the wrong function, with
potentially disastrous
consequences.
Keyboard accelerators
Menus often offer keyboard accelerators, key combinations that
have the same effect
as selecting the menu item. This allows more expert users,
familiar with the system, to
manipulate things without moving off the keyboard, which is
often faster. The
accelerators are often displayed alongside the menu item so that
frequent use makes
them familiar.
Buttons
Buttons are individual and isolated regions within display that
can be selected by the
user to invoke specific operations. These regions are referred
to as buttons because
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they are purposely made to resemble the push buttons you would
find on a control
panel. ‘Pushing’ the button invokes a command, the meaning of
which is usually
indicated by a textual label or a small icon.
Radio Buttons
Buttons can also be used to toggle between two states,
displaying status information
such as whether the current font is italicized or not in a word
processor, or selecting
options on a web form. Such toggle buttons can be grouped
together to allow a user to
select one feature form a set of mutually exclusive options,
such as the size in points
of the current font. These are called radio buttons.
Check boxes
It a set of options is not mutually exclusive, such as font
characteristics like bold,
italic and underlining, and then a set of toggle buttons can be
used to indicate the
on/off status of the options. This type of collection of buttons
is sometimes referred to
as check boxes
Toolbars
Many systems have a collection of small buttons, each with
icons, placed at the top or
side of the window and offering commonly used functions. The
function of this
toolbar is similar to a menu bar, but as the icons are smaller
than the equivalent text
more functions can be simultaneously displayed. Sometimes the
content of the toolbar
is fixed, but often users can customize it, either changing
which functions area made
available, or choosing which of several predefined toolbars is
displayed
Palettes
In many application programs, instructions can either one of
several modes. The
defining characteristic of modes is that the interpretation of
actions, such as
keystrokes or gestures with the mouse, changes as the mode
change. For example,
using the standard UNIX text editor vi, keystrokes can be
interpreted either as
operations to insert characters in the document or as operations
to perform file
manipulation. Problems occur if the user is not aware of the
current mode. Palettes are
a mechanism for making the set of possible modes and the active
mode visible to the
user. A palette is usually a collection of icons that are
reminiscent of he purpose of the
various modes. An example in a drawing package would be a
collection of icons to
indicate the pixel color or pattern that is used to fill in
objects, much like an artist’s
palette for paint.
Some systems allow the user to create palettes from menus or
toolbars. In the case of
pull-down menus, the user may be able ‘tear off’ the menu,
turning it into a palette
showing the menu items. In the case of toolbars, he may be able
to drag the toolbar
away from its normal position and place it anywhere on the
screen. Tear-off menus
are usually those that are heavily graphical anyway, for example
line style of color
selection in a drawing package.
Dialog boxes
Dialog boxes are information windows used by the system to bring
the user’s
attention to some important information, possibly an error or a
warning used to
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prevent a possible error. Alternatively, they are used to invoke
a sub dialog between
user and system for a very specific task that will normally be
embedded within some
larger task. For example, most interactive applications result
in the user creating some
file that will have to be named and stored within the filing
system. When the user or
the file and indicate where it is to be located within the
filing system. When the save
sub dialog is complete, the dialog box will disappear. Just as
windows are used to
separate the different threads of user-system dialog, so too are
dialog boxes used to
factor out auxiliary task threads from the main task dialog.
15.2 Interaction Paradigms
We believe that we now build interactive systems that are more
usable than those built
in the past. We also believe that there is considerable room for
improvement in
designing more usable systems in the future. The great advances
in computer
technology have increased the power of machines and enhanced the
bandwidth of
communication between human and computer. The impact of the
technology alone,
however, is not sufficient to enhance its usability. As our
machines have become
more powerful, they key to increased usability has come from the
creative and
considered application of the technology to accommodate and
augment the power of
the human. Paradigms for interaction have for the most part been
dependent upon
technological advances and their creative application to enhance
interaction.
By interaction paradigm, it is meant a particular philosophy or
way of thinking about
interaction design. It is intended to orient designers to the
kinds of questions they
need to ask. For many years the prevailing paradigm in
interaction design was to
develop application for the desktop – intended to be used by
single user sitting in
front of a CPU, monitor, keyboard and mouse. A dominant part of
this approach was
to design software applications that would run using a GUI or
WIMP interface.
Recent trend has been to promote paradigms that move beyond the
desktop. With the
advent of wireless, mobile, and handheld technologies,
developers started designing
applications that could be used in a diversity of ways besides
running only on an
individual’s desktop machine.
We will discuss different paradigms here.
Time sharing
In the 1940s and 1950s, the significant advances in computing
consisted of new
hardware technologies. Mechanical relays were replaced by vacuum
electron tubes.
Tubes were replaced by transistors, and transistors by
integrated chips, all of which
meant that the amount of sheer computing power was increasing by
orders of
magnitude. By the 1960s it was becoming apparent that the
explosion of growth in
computing power would be wasted if there were not an equivalent
explosion of ideas
about how to channel that power. One of the leading advocates of
research into
human-centered applications of computer technology was J.C.R
Licklider, who
became the director of the Information Processing Techniques
Office of the US
Department of Defense’s Advanced Research Agency (ARPA). It was
Licklider’s
goal to finance various research centers across the United
States in order to encourage
new ideas about how best to apply the burgeoning computing
technology.
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One of the major contributions to come out of this new emphasis
in research was the
concept of time-sharing, in which a single computer could
support multiple users.
Previously, the human was restricted to batch sessions, in which
complete jobs were
submitted on punched cards or paper tape to an operator who
would then run them
individually on the computer. Time-sharing systems of the 1960s
made programming
a truly interactive venture and brought about a subculture of
programmers known as
‘hackers’ – single-minded masters of detail who took pleasure in
understanding
complexity. Though the purpose of the first interactive
time-sharing systems was
simply to augment the programming capabilities of the early
hackers, it marked a
significant stage in computer applications for human use.
Video display units
As early as the mid-1950s researchers were experimenting with
the possibility of
presenting and manipulating information from a computer in the
form of images on a
video display unit (VDU). These display screens could provide a
more suitable
medium than a paper printout for presenting vast quantities of
strategic information
for rapid assimilation. It was not until 1962, however, when a
young graduate student
at the Massachusetts Institute of Technology (MIT), Ivan
Sutherland, astonished the
established computer science community with the Sketchpad
program, that the
capabilities of visual images were realized.
Sketchpad demonstrated two important ideas. First, computers
could be used for more
than just data processing. They could extend the user’s ability
to abstract away from
some levels of detail, visualizing and manipulating different
representations of the
same information. Those abstractions did not have to be limited
to representations in
terms of bit sequences deep within the recesses of computer
memory. Rather, the
abstraction could be make truly visual. To enhance human
interaction, the information
within the computer was made more amenable to human consumption.
The computer
was made to speak a more human language, instead of the human
being forced to
speak more like a computer. Secondly, Sutherland’s efforts
demonstrated how
important the contribution of one creative mind could be to the
entire history of
computing.
Programming toolkits
Dougles Engelbart’s ambition since the early 1950s was to use
computer technology
as a means of complementing human problem-solving activity.
Engelbart’s idea as a
graduate student at the University f California at Berkeley was
to use the computer to
teach humans. This dream of naïve human users actually learning
from a computer
was a stark contrast to the prevailing attitude of his
contemporaries that computers
were purposely complex technology that only the intellectually
privileged were
capable of manipulating.
Personal computing
Programming toolkits provide a means for those with substantial
computing skills to
increase their productivity greatly. But Engelbart’s vision was
not exclusive to the
computer literate. The decade of the 1970s saw the emergence of
computing power
aimed at the masses, computer literate or not. One of the first
demonstrations that the
powerful tools of the hacker could be made accessible to the
computer novice was a
graphics programming language for children called LOGO. The
inventor, Seymen
Papert, wanted to develop a language that was easy for children
to use. He and his
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colleagues from MIT and elsewhere designed a computer-controlled
mechanical turtle
that dragged a pen along a surface to trace its path. In the
early 1970s Alan Kay view
of the future of computing was embodied in small, powerful
machines, which were
dedicated to single users, that is personal computers. Together
with the founding team
of researchers at the Xerox Palo Alto Research Center, Kay
worked on incorporating
a powerful and simple visually based programming environment,
Smalltalk, for the
personal computing hardware that was just becoming feasible. As
technology
progresses, it is now becoming more difficult to distinguish
between what constitutes
a personal computer, or workstation, and what constitutes a
mainframe.
Window systems and the WIMP interface
With the advent and immense commercial success of personal
computing, the
emphasis for increasing the usability of computing technology
focused on addressing
the single user who engaged in a dialog with the computer in
order to complete some
work. Humans are able to think about more than one thing at a
time, and in
accomplishing some piece of work, they frequently interrupt
their current train of
thought to pursue some other related piece of work. A personal
computer system
which forces the user to progress in order through all of the
tasks needed to achieve
some objective, from beginning to end without any diversions,
does not correspond to
that standard working pattern. If the personal computer is to be
an effective dialog
partner, to must be as flexible in its ability to change the
topic as the human is.
But the ability to address the needs of a different user task is
not the only requirement.
Computer systems for the most part react to stimuli provided by
the user, so they are
quite amenable to a wandering dialog initiated by the user. As
the ser engages in more
than one plan of activity over a stretch of time, it becomes
difficult for him to
maintain the status of the overlapping threads of activity.
Interaction based on windows, icons, menus, and pointers—the
WIMP interface—is
now commonplace. These interaction devices first appeared in the
commercial
marketplace in April 1981, when Xerox Corporation introduced the
8010 Star
Information System.
The metaphor
Metaphor is used quite successfully to teach new concepts in
terms of ones, which are
already understood. It is no surprise that this general teaching
mechanism has been
successful in introducing computer novices to relatively foreign
interaction
techniques. Metaphor is used to describe the functionality of
many interaction
widgets, such as windows, menus, buttons and palettes.
Tremendous commercial
successes in computing have arisen directly from a judicious
choice of metaphor. The
Xerox Alto and Star were the first workstations based on the
metaphor of the office
desktop. The majority of the management tasks on a standard
workstation have to do
with the file manipulation. Linking the set of tasks associated
with file manipulation
to the filing tasks in a typical office environment makes the
actual computerized tasks
easier to understand at first. The success of the desktop
metaphor is unquestionable.
Another good example in the personal computing domain is the
widespread use of the
spreadsheet for accounting and financial modeling.
Very few will debate the value of a good metaphor for increasing
the initial
familiarity between user and computer application. The danger of
a metaphor is
usually realized after the initial honeymoon period. When word
processors were first
introduced, they relied heavily on the typewriter metaphor. The
keyboard of a
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computer closely resembles that of a standard typewriter, so it
seems like a good
metaphor from any typewriter. For example, the space key on a
typewriter is passive,
producing nothing on the piece of paper and just moving the
guide further along the
current line. For a typewriter, a space is not a character.
However, for a word
processor, the blank space is a character, which much be
inserted within a text just as
any other character is inserted. So an experienced typist is not
going to be able to
predict his experience with a preliminary understanding of a
word processor.
Another problem with a metaphor is the cultural bias that it
portrays. With the
growing internationalization of software, it should not be
assumed that a metaphor
will apply across national boundaries. A meaningless metaphor
will only add another
layer of complexity between the user and the system.
Direct Manipulation
In the early 1980s as the price of fast and high-quality
graphics hardware was steadily
decreasing, designers were beginning to see that their products
were gaining
popularity as their visual content increased. As long as the
user-system command line
prompt computing was going to stay within the minority
population of the hackers
who reveled in the challenge of complexity. In a standard
command line interface, the
only way to get any feedback on the results of previous
interaction is to know that you
only have to ask for it and to know how to ask for it. Rapid
visual and audio feedback
on a high-resolution display screen or through a high-quality
sound system makes it
possible to provide evaluative information for every executed
user action.
Rapid feedback is just one feature of the interaction technique
known as direct
manipulation. Ben Shneiderman is attributed with coining this
phrase in 1982 to
describe the appeal of graphics-based interactive systems such
as Sketchpad and the
Xerox Alto and Star. He highlights the following features of a
direct manipulation
interface.
. visibility of the
objects of interest
. incremental action
at the interface with rapid feedback on all actions
. reversibility of
all actions, so that users are encouraged to explore without
severe penalties
. syntactic
correctness of all actions, so that every user action is a legal
operation
. replacement of
complex command language with actions to manipulate
directly the visible objects.
The first real commercial success which demonstrated the
inherent usability of direct
manipulation interfaces for the general public was the Macintosh
personal computer,
introduced by Apple Computer, Inc. in 1984 after the relatively
unsuccessful
marketing attempt in the business community of the similar but
more pricey Lisa
computer. The direct manipulation interface for the desktop
metaphor requires that the
documents and folders are made visible to the user as icons,
which represent the
underlying files and directories. An operation such as moving a
file from one
directory to another is mirrored as an action on the visible
document, which is picked
and dragged along the desktop from one folder to the next.
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Language versus action
Whereas it is true that direct manipulation interface make some
tasks easier to
perform correctly, it is equally true that some tasks are more
difficult, if not
impossible. Contrary to popular wisdom, it is not generally true
that action speak
louder than words. The image, projected for direct manipulation
was of the interface
as a replacement for the underlying system as the world of
interest to the user. Actions
performed at the interface replace any need to understand their
meaning at any deeper,
system level. Another image is of the interface s the
interlocutor or mediator between
the user and the system. The user gives the interface
instructions and it is then the
responsibility of the interface to see that those instructions
are carried out. The usersystem
communication is by means of indirect language instead of direct
actions.
We can attach two meaningful interpretations to this language
paradigm. The first
requires that the user understands how the underlying system
functions and the
interface as interlocutor need not perform much translation. In
fact, this interpretation
of the language paradigm is similar to the kind of interaction,
which existed before
direct manipulation interfaces were around. In a way, we have
come full circle.
The second interpretation does not require the user to
understand the underlying
system’s structure. The interface serve a more active role, as
it must interpret between
the intended operation as requested by the user and the possible
system operations
that must be invoked to satisfy that intent. Because it is more
active, some people
refer to the interface as an agent in these circumstances. This
kind of language
paradigm can be seen in some internal system database, but you
would not know how
that information is organized.
Whatever interpretation is attached to the language paradigm, it
is clear that it has
advantages and disadvantages when compared with the action
paradigm implied by
direct manipulation interfaces. In the action paradigm, it is
often much easier to
perform simple tasks without risk o certain classes or error.
For example, recognizing
and pointing to an object reduces the difficulty of
identification and the possibility of
misidentification. On the other hand, more complicated tasks are
often rather tedious
to perform in the action paradigm, as they require repeated
execution of the same
procedure with only minor modification. In the language
paradigm, there is the
possibility describing a generic procedure once and then leaving
it to be executed
without further user intervention.
The action and language paradigms need not be completely
separate. In the above
example two different paradigms are distinguished by saying that
generic and
repeatable procedures can be described in the language paradigm
and not in the action
paradigm. An interesting combination of the two occurs in
programming by example
when a user can perform some routine tasks in the action
paradigm and the system
records this as a generic procedure. In a sense, the system is
interpreting the user’s
actions as a language script that it can then follow.
Hypertext
In 1945, Vannevar Bush, then the highest-ranking scientific
administrator in the US
war effort, published an article entitled ‘As We May Think’ in
The Atlantic Monthly.
Bush was in charge of over 6000 scientists who had greatly
pushed back the frontiers
of scientific knowledge during the Second World War. He
recognized that a major
drawback of these prolific research efforts was that it was
becoming increasingly
difficult to keep in touch with the growing body of scientific
knowledge in the
literature. In his opinion, the greatest advantages of this
scientific revolution were to
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be gained by those individuals who were able to keep abreast of
an ever-increasing
flow of information. To that end, he described an innovative and
futuristic
information storage and retrieval apparatus – the memex –, which
was constructed
with technology wholly existing in 1945 and aimed at increasing
the human capacity
to store and retrieve, connected pieces of knowledge by
mimicking our ability to
create random associative links.
An unsuccessful attempt to create a machine language equivalent
of the memex on
early 1960s computer hardware led Nelson on a lifelong quest to
produce Xanadu, a
potentially revolutionary worldwide publishing and information
retrieval system
based on the idea of interconnected, non-linear text and other
media forms. A
traditional paper is read from beginning to end, in a linear
fashion. But within that
text, there are often ideas or footnotes that urge the reader to
digress into richer topic.
The linear format for information does not provide much support
for this random and
associated browsing task. What Bush’s memex suggested was to
preserve the nonlinear
browsing structure in the actual documentation. Nelson coined
the phrase
hypertext in the mid 1960s to reflect this non-linear text
structure.
Multi-modality
The majority of interactive systems still use the traditional
keyboard and a pointing
device, such as a mouse, for input and are restricted to a color
display screen with
some sound capabilities for output. Each of these input and
output devices can be
considered as communication channels for the system and they
correspond to certain
human communication channels. A multi-modal interactive system
is a system that
relies on the use of multiple human communication channels. Each
different channel
for the user is referred to as a modality of interaction. In
this sense, all interactive
systems can be considered multi-model, for human have always
used their visual and
haptic channels in manipulating a computer. In fact, we often
use our audio channel to
hear whether the computer is actually running properly.
However, genuine multi-modal systems rely to an extent on
simultaneous use of
multiple communication channels for both input and output.
Humans quite naturally
process information by simultaneous use of different channels.
Computer-supported cooperative work
Another development in computing in the 1960s was the
establishment of the first
computer networks, which allowed communication between separate
machines.
Personal computing was all about providing individuals with
enough computing
power so that they were liberated from dumb terminals, which
operated on a timesharing
systems. It is interesting to note that as computer networks
become
widespread, individuals retained their powerful workstations but
now wanted to
reconnect themselves to the rest of the workstations in their
immediate working
environment, and even throughout the world. One result of this
reconnection was the
emergence of collaboration between individuals via the computer
– called computer –
supported cooperative work, or CSCW.
The main distinction between CSCW systems and interactive
systems designed for a
single user is that designer can no longer neglect the society
within which any single
user operates. CSCW systems are built to allow interaction
between humans via the
computer and so the needs of the many must be represented in the
one product. A fine
example of a CSCW system is electronic mail – email – yet
another metaphor by
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which individuals at physically separate locations can
communicate via electronic
messages that work in a similar way to conventional postal
systems.
The World Wide Web
Probably the most significant recent development interactive
computing is the World
Wide Web, often referred to as just the web, or WWW. The web is
built on top of the
Internet, and offers an easy to use, predominantly graphical
interface to information,
hiding the underlying complexities of transmission protocols,
addresses and remote
access to data.
The Internet is simply a collection of computers, each linked by
any sort of data
connections, whether it be slow telephone line and modem or
high-bandwidth optical
connection. The computers of the Internet all communicate using
common data
transmission protocols and addressing systems. This makes it
possible for anyone to
read anything from anywhere, in theory, if it conforms to the
protocol. The web builds
on this with its own layer of network protocol, a standard
markup notation for laying
out pages of information and a global naming scheme. Web pages
can contain text,
color images, movies, sound and, most important, hypertext links
to other web pages.
Hypermedia documents can therefore be published by anyone who
has access to a
computer connected to the Internet.
Ubiquitous computing
In the late 1980s, a group of researchers at Xerox PARC led by
Mark Weiser, initiated
a research program with the goal of moving human-computer
interaction away from
the desktop and out into our everyday lives. Weiser observed.
The most profound technologies are those that disappear. They
weave themselves into
the fabric of everyday life until they are indistinguishable
from it.
These words have inspired a new generation of researchers in the
area of ubiquitous
computing. Another popular term for this emerging paradigm is
pervasive computing,
first coined by IBM. The intention is to create a computing
infrastructure that
permeates our physical environment so much that we do not notice
the computer may
longer. A good analogy for the vision of ubiquitous computing is
the electric motor.
When the electric motor was first introduced, it was large, loud
and very noticeable.
Today, the average household contains so many electric motors
that we hardly ever
notice them anymore. Their utility led to ubiquity and, hence,
invisibility.
Sensor-based and context-aware interaction
The yard-scale, foot-scale and inch-scale computers are all
still clearly embodied
devices with which we interact, whether or not we consider them
‘computers’. There
are an increasing number of proposed and existing technologies
that embed
computation even deeper, but unobtrusively, into day-to-day
life. Weiser’s dream was
computers anymore’, and the term ubiquitous computing
encompasses a wide range
from mobile devices to more pervasive environments. |
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