Transcript Communications: from Shakespeare to Virtual Reality

Communications:
from Shakespeare to Virtual
Reality
Dr. Ronald Pose
Faculty of Information Technology
Monash University
Communication
 What
does it mean to
‘communicate’ ?
 What is required to enable
‘communication’ ?
 How can one know if
‘communication’ has been
achieved ?
Communication (2)
 ‘Communication’
involves at least
2 parties, one of whom
communicates ‘something’ to
other(s)
 In order to understand
‘communication’ we need to
understand the nature of the
communicating parties, and also
the nature of the ‘something’
Communicating entities
 The
parties that are
communicating may be people or
may be machines or other artifacts
created for some purpose relating
to the communication
 You may hear about
communications networks
comprising many interconnected
computers; Is this communication?
What is communicated?
 Something?
 Information?
 Data?
 Ideas?
 Bits?
 We
can give many definitions but in
essence let us call the ‘something’ that
is communicated, ‘information’
What is information?
 Shannon
defined ‘information’ in terms
related to ‘entropy’, a measure of the
‘disorder’ of the universe
 This provides a nice analytic definition
but let us avoid any mathematical
intricacies and instead just consider
the gaining of information as
equivalent to learning something new,
something you did not already know.
What is information? (2)
I contend that information is ‘physical’
 that it cannot exist other than in some
physical form
 that it is not simply an abstraction
 If this is so, then communication is the
transfer of information from one party to
other(s)
 It then follows that communication must
take the form of a physical process
 Not everyone takes this viewpoint
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Shakespeare’s 18th Sonnet
Shall I compare thee to a summer's day?
Thou art more lovely and more temperate:
Rough winds do shake the darling buds of May,
And summer's lease hath all too short a date:
Sometime too hot the eye of heaven shines,
And often is his gold complexion dimm'd;
And every fair from fair sometime declines,
By chance or nature's changing course untrimm'd;
But thy eternal summer shall not fade
Nor lose possession of that fair thou owest;
Nor shall Death brag thou wander'st in his shade,
When in eternal lines to time thou growest:
So long as men can breathe or eyes can see,
So long lives this and this gives life to thee.
Shakespeare
communicating with us
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Who are the communicating parties?
– Shakespeare communicating with us?
What is being communicated?
– Shakespeare’s 18th sonnet?
– The words of the 18th sonnet?
– A representation of the 18th sonnet?
– A representation of the words of the 18th sonnet?
How is the communication taking place?
Shakespeare
communicating with us (2)
Let us take Shakespeare (whoever that may
be) as the source of the communication, and
ourselves as the recipients
 Is it important that we know who/what/where
the communication originated?
 Is it important that the originator of the
communication knows anything about the
recipients?
 Does communication have to be intentional?
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Shakespeare
Let us assume that Shakespeare was a man
 If we were to assume otherwise would that
affect the nature of the communication of the
sonnet?
 What is a sonnet?
 Does it matter that we know this ‘information’
is a sonnet?
 How does one know that communication has
taken place?
 What is the ‘information content’ of the
communication?
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Sonnet
A Shakespearean, or English sonnet consists
of 14 lines
 each line contains ten syllables
 each line is written in iambic pentameter in
which a pattern of a non-emphasized syllable
followed by an emphasized syllable is
repeated five times
 The rhyme scheme in a Shakespearean
sonnet is ABAB CDCD EFEF GG in which
the last two lines are a rhyming couplet.
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Communicating a sonnet
We know now that we are dealing with an
English sonnet, and how English sonnets are
structured
 We thus are better able to interpret /
understand the sonnet
 What about the language?

– English has changed a great deal since
Shakespeare
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Given the changes in language and the
general ignorance of what a sonnet is, can
we say that the sonnet as Shakespeare
conceived it, has been communicated?
Communicating a sonnet
We know now that we are dealing with an
English sonnet, and how English sonnets are
structured
 We thus are better able to interpret /
understand the sonnet
 What about the language?

– English has changed a great deal since
Shakespeare
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Given the changes in language and the
general ignorance of what a sonnet is, can
we say that the sonnet as Shakespeare
conceived it, has been communicated?
Representation
No matter what a sonnet is, I contend that
what is communicated is at most a
representation of a sonnet
 A sonnet may be represented in many ways:
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– Text
– Sound recording of a person reciting the sonnet
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The key thing is that a representation
purposefully includes a selection of the
information content of the sonnet
– Note that a representation has a purpose and
that the purpose influences the selection of the
information to be included
Representation as the thing
that is communicated
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I contend that what is actually communicated is a
‘representation’ rather than the actual thing
I contend that depending on the purpose of the
communication, different representations may be
used, perhaps emphasizing different information
I contend that the representation is encoded into a
convenient form for communication under the
assumption that a suitable decoder is employed by
the recipient
I contend that there is usually an assumption that
the recipient can use the representation to be
informed about the original thing
Communication schematic
a dna ™e miTkciuQ
ro s serp moced )de s serp mocnU( FFIT
.erutcip siht ee s ot dedeen era
Sonnet
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Communication processes
Thing is created
 Representation of ‘thing’ is created for a
particular purpose incorporating information
relevant to that purpose
 The representation is encoded in a language
or form understandable by the intended
recipients
 The encoded representation is sent to the
recipient
 Recipient decodes the representation
 Information obtained via the representation
gives the recipient some notion of the original
thing
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Observations
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The ‘thing’ may or may not exist as a physical
object but must have information content, hence
must in some way have a physical existence
The representation must at best contain a subset of
the content of the ‘thing’
– It is not the ‘thing’ otherwise communication
would be akin to cloning
The representation may involve a language such as
English, or a more formal language such as Fortran
or mathematical notations, or be pictorial, or of
other forms
The representation may be encoded into binary,
compressed, or otherwise transformed for
convenience in transfering to the recipient
Observations (2)
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Not all representations are equal
– Some representations may be better at preserving the information
that they are intended to convey
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A representation in essence reflects a model of the ‘thing’ in
which salient aspects are preserved
The mapping between the ‘thing’ and a ‘representation’ of
the thing is not intrinsic in the representation or the thing,
hence it may be necessary to communicate not only the
representation but also more details of the model that links it
back to the ‘thing’
– i.e. beware of assuming that the recipient can understand the
language of the representation
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The encoding of the representation, whether it be a
language text, a picture, or some other form, often ends up
as a binary stream in modern digital communications
technology
– This has to be decoded to recover the representation, so knowledge
of the encoding/decoding process may also have to be
communicated
Back to Computer Science
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How does this seemingly esoteric discussion of
representation, encoding and communication relate to
Computer Science or Software Engineering?
Well, in fact this is the essence of Computer Science
What do we do with computers?
– We model aspects of the natural or man-made world and derive
information from that model that we can use to help us manage or
manipulate the world
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A computer system may be used by a bank to manage its
assets, loans, borrowers and lenders
– A model is made of the relevant features of those parts of the
banking world that are of interest
– Borrowers and lenders may be represented by name, address, age,
some view of their financial and other assets, etc.
– At the base level these may come down to character strings, integers, etc.
– The banking transactions are in effect communications among these
represented entities in which information is transferred appropriately, perhaps
within the computer system, perhaps between networked computer systems
– There is also communication between the bank’s computer systems
and its users, both staff and customers, in branches and at ATMs
Forms of representation
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Our banking example used mostly textual and numeric
representational forms
Other applications may use graphical forms
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Radar images representing rainfall
Synoptic charts depicting isobars of air pressure
Charts depicting population density
Architectural plans
Pert charts
Flow charts
Anatomical or botanical illustrations
What about sound and music recordings as
representations?
There are many choices of representations available
– The ‘correct’ choice depends on the purpose for the representation
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The richness and complexity of the representation will
impose demands on the encoding and transmission
components of the communication system
Pictorial representation
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Pictorial representation(2)
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Picasso using a cubist representation of a woman
enables us to see the nose and mouth in profile and
the eyes from the front
We can see so much more in this representation
than would be possible if one took a photograph
with a conventional camera
Pictorial representation(3)
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Drawing plants is often a better way to record
them than photography because through drawing
it is possible to highlight on a single page
important features as well as to show different
stages of development
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Pictorial representation(4)
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One-point perspective
Pictorial representation(5)
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two-point perspective
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three-point perspective
Pictorial representation(6)
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Note that none of these pictorial representations is
a complete description of the underlying ‘thing’
being represented
The various views expose different aspects of the
thing being represented
Different information is being presented
Thus as in textual, poetic or other representations
there is no true representation
Somewhat arbitrary choices are made, and the only
real indication of quality is whether it serves its
purpose in conveying the required information
Virtual Reality
(representation)
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In our human experience we employ all our senses
to gather information about the environment in
which we live
Our interactions with computer-based models
generally are textual or graphical
Virtual Reality systems attempt to engage more of
the human user’s senses to try to convey more
information, or perhaps different aspects or
perspectives of the world being represented
Such systems can use stereoscopic moving
images, stereophonic sound, perhaps some haptic
feedback, even more exotic things such as
temperature
Virtual Reality
(representation)
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In our human experience we employ all our senses
to gather information about the environment in
which we live
Our interactions with computer-based models
generally are textual or graphical
Virtual Reality systems attempt to engage more of
the human user’s senses to try to convey more
information, or perhaps different aspects or
perspectives of the world being represented
Such systems can use stereoscopic moving
images, stereophonic sound, perhaps some haptic
feedback, even more exotic things such as
temperature
Casey Chow modelling a Vector Research V8 with a
mechanically coupled tracker
Communication revisited
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Let us assume human-human communication
I assume that you function as sentient beings in some way
similarly to the way I do
I have a mental model, a representation perhaps
encapsulated as part of the state of my brain, that I wish to
communicate to you
Thus as an outcome of the communication process I wish to
change the state of your brain to incorporate a mental model
of the ‘thing’ I am communicating
How presumptuous of me to want to change your brain, to
want to change the very essence of your being
How do I know that I have achieved this?
Can I ever achieve such communication?
What has this to do with computer science or software
engineering?
Computation
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What do we mean by computation?
What does a computer program do?
Typically computer programs model real-world
phenomena, processes, things
In order to do this a representation or model is
created that incorporates salient features of aspects
of the real world that are relevant
This is represented in the form of data structures
and algorithms encoded in various formal computer
languages
These representations take the physical form of
state in some computational machinery
Doesn’t this seem like an analogous situation to the
case of communication we have been exploring?
Computation (2)
Consider the execution of a typical computer
program on a von Neumann computer or if
you prefer in a Turing machine
 Typically the algorithm will comprise a
number of ‘assignment statements’ which
copy values (perhaps modified) from one
memory location to another
– Surely this is an instance of communication
– Values moving from one place to another is
communication
 Is there a difference between computation
and communication?
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Computation (3)
Our representation of the aspects of the
world we are modelling with our computer
program may be expressed in a computer
programming language
 In one sense we can consider a computer
programmer as communicating his model of
the world of interest to the computer system
using a language such as Java
 The computer system interprets this program
and so may manipulate the representation of
the world of concern
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Computation (4)
OK, so a computer programmer
communicates to the computer using a
programming language to express the
representation of the model
 The computer system communicates with its
users via its input/output system whereby it
can obtain data to feed its representation of
the world and it can provide output to the
users or perhaps to other computer systems
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Computation versus
Communication
When I claim that communication and
computation are essentially equivalent, in fact
two ways of viewing the same phenomenon, I
speak not of a highly abstract,
mathematically equivalent model in which
communication and computation have the
same forms, rather I know this through
experience of seeing and building
communications networks and computer
hardware
 The physical structures of communications
networks and of computers are the same
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Communications Network
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A computer communications network comprising
computers interconnected with wires and switches
Inside a computer
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A 14 transistor circuit that forms a full adder
A+B+Carry-in -> Sum, Carry-out
A modern digital electronic computer can be made entirely of
wires and switches (transistors)
Computers versus
communication networks
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Computers and communications networks can both be made
from wires of various quality (to conduct electricity) and
switches of various quality (e.g. transistors)
Both simply require some energy (e.g. electricity)
Both do communications in that information is moved around
along the wires and through switches
There seems to be an arbitrary boundary between the
computers and the communications network that
interconnects them
When one looks closely all one sees is a richly interconnected
set of switches
We view such a set of interconnected switches as a computer
when we interpret the information flows and transformations
happening with such a system as a computation
I contend we can do computation in an analogous way in a
communications network
Computation versus
communication
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OK, so we can see that computers and communications
networks, the physical devices in which computation and
communication are performed, have the same structure and
form of operations
Can we relate the more theoretical descriptions of
computation (Turing) and communication (Shannon)?
The answer is yes, but it is a much more subtle and abstract
path to take
If one does it carefully one will reach the same conclusion,
that the distinction between computation and communication
is simply where one draws the boundary between the
computer and the interconnection network over which
computers communicate
Another way to view it would be as a single distributed
computer system, or as a network of individual computers
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Summary
We have looked at communication, human-human and humancomputer and computer-computer
We discovered that communication involves representation and
encoding of the representation using some language or notation
The encoded representation is transferred to the recipient
Communication is only successful if the recipient knows how to
decode the representation and can also relate the
representation to the intended informational domain
We also discovered that our computational systems also involve
an analogous representational and encoding process
When we examine the computer and communications hardware
we find similar structures in both and the same principles of
operation
We conclude that communication and computation are
essentially the same thing, or perhaps two ways of looking at
the same thing
One can take Turing’s computational model and Shannon’s
communicational model and demonstrate the same thing in a
more mathematical way
Further exploration
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In preparing this talk I looked for documents exploring the
relationship of communication and computation
I also looked for documents describing representation
There is a long history of study of what the essence of an object
or of the world really is, going back to the ancient Greeks and
beyond
This notion of ‘being’ or if you like, what something ‘is’ is the
realm of ONTOLOGY, not to be confused with the current
hijacking of the word to mean a controlled vocabulary enabling
discourse about a domain
The representation of something and its description and
encoding via language must have ways of signifying what is
being represented. This is the realm of SEMIOTICS and its
branch called SEMANTICS
What we know about the world is often communicated in
various ways so one may also be interested in
EPISTEMOLOGY, the study of knowledge
Another presentation
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For those that feel inclined to another episode of
unusual and ‘politically incorrect’ thinking about
computation and communication, let me invite you to
another talk, focusing on Human-Computer Interaction
(HCI), where we will explore in some detail the use of
Virtual Reality systems as the ultimate HCI, and
whether it is a good thing
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Is Virtual Reality the ultimate HCI for all computer
usage, work and play?
Dr. Ronald Pose
Tuesday 2nd June 2009, Lecture Theatre H3
Monash University, Clayton Campus