M150 =“ PREPERATION NOTES

• Read the news section of the site weekly

• Start with 'course guide' and then 'course companion'

• The study calendar is the only place here the assignments will be published, but also on the website

• Tma01 = 15%

• 2 to 5 are 20% each

• TMA05 and CMA41 are compulsory

• No substitution

• Need 40% on everything, except TMA05, which needs 35%

• You only pass or fail

• Units nine and ten are optional

  • Useful if you want to go onto programming

• Help

  • www.open.ac.uk/computing-help-desk

  • OU-Computing-Helpdesk@open.ac.uk

  • +44 (0)1908 653972

• Check errata in each unit with this preparation document

COURSE GUIDE

• Three blocks

  • Sixteen units

    • Each unit is two weeks @ 10-15 hours

• CME = computer marked exercise = optional

Course themes

• Ubiquity and universality

• Change and transience

• Demythologising and mystifying

• Complexity and cognitive overload

• Abstraction and modeling

• Communication and standards

• Access and privacy

Forums

• Tutor

• Regional

Section seven of course companion gives guidance on how to write4 assignments.

COURSE COMPANION

Go to personal homepage

• 'Policy documents for students'

  • Assesment handbook

    • How to submit assignments is there

  • Actual tasks at the end of each unit are on cd.

  • CMA are on calendar

    • Will help in preparation for the actual one.

    • CMA41 = downloadable also

• Units comprise of blocks

• Bookmark the homepage

• Look at the course news weekly

• Read the code of conduct on forums

  • Tutor groups

  • Regional groups

  • M150 Student enquiries

    • Though tutor is the first point of contact

GET FIRST CLASS

TMA's are available closer to the date

• Try to answer the tma while you are studying

• Don't syndicate, i.e. accidentally present group work as your own

• Download the software guide as it's different to the one you have.

M150

UNIT ONE

• Data stored about you makes a persona

Unit Aims

• Introduce course themes

Data = a piece of information, i.e one dollar

Information = linked data, i.e. ice cream is a dollar

In philosophy, sensation must become a form so it can become an abstract thing like thought

eg. so that something can be thought about and conveyed to another person

Written form means can convey things across time and space

More objective measures

• temperature

Perceptual data = that sensation can perceive

• Reaction

  • Instinctive

  • Reflective

    • Classify etc

Sign/symbol = conveys info other than by direct representation eg. beeping at crossing, symbols in paintings etc.

• A sign/symbol is not a representation because:

  • Has meaning apart from direct representation

  • Understood through agreed meaning

• Words are signs

• Signs can be:

  • Visual

  • Auditory

  • Tactile

• Humans like turning data into information

  • Machines give more data

    • eg. temperature

  • Muscle machines

  • Remote sensing

    • Satellites

    • Medical diagnosis

  • Store

  • Transmit

Parameter = a property/characteristic of something which is measurable/quantifiable

• Layering data

  • Eg. maps

    • Lat. and long.

    • Contour

    • Features

    • Names

  • eg. cholera

    • = Medical cartography

      • Showed water-borne disease

  • Leave in and out

    • Fit for purpose

Internet = physical network of computers

Web =“ interlinked data

• Data

  • Simple

  • Complex

    • DNA =“ Deoxyribonucleic acid

      • Crime

      • Medical

      • Identification

    • Twisted ladder of chemical pairs

    • Four chemicals

      • A =“ adenine

      • C =“ cytosine

      • G =“ Guanine

      • T =“ Thymine

    • Rules of pairing

      • A to T

      • C to G

    • Rung is called a 'pair'

    • Nucleotide?? - base pair plus structural molecules (i.e. ladder sides)

    • Sequences of base pairs are sections that form hereditary

• English

  • 26 letters

  • Rules

    • MS not at start

    • Plus S is plural

  • DNA and English = infinite possibilities

  • DNA cont.

    • Letters are signs?

    • Combined according to rules = genes

    • Chromosomes are dna strands

    • 46 in 23 pairs

    • So:

      • Gene = word

      • Chromosome = Possible utterances

      • 23 chromosome pairs = encyclopedia

    • Chromosomes are made of dna from varying strands

    • Human chromosome

      • 26.3 base pairs

      • 23 pairs = 3.2 billion

      • Varies = genetic diversity

Genome = map of genes i.e. which gives rise to which characteristics.

One human chromosome = 30/40K genes

Art

• Computer can add flexibility/possibility

• Make many copies

Machines

• Interface

  • choices

  • information

• Actuators = cause mechanical parts to work

• Sensors

  • (managed)

• Database server

  • Get spec. info

• Distributed system

  • Different computers communicate over a network to get info for the same user.

Unit Two =“ Representation

• communication

  • Convention

  • representation

  • Social spaces

  • Join Facebook OU

  • Web 2.0

    • Blogs

    • Wiki

Problem Solving

• Instruction

• Inputs

• Communicate solution

  • Network if ap.

  • Transform input to output

  • Interferometry

    • Many radio telescopes pointed at the same area =“ combined is called Very Long Baseline Interferometry

      • Super cluster computers

        • = networked ordinary to become supercomputers

  • In/out data

    • eg. immigration

      • Iris in

      • Turnstile out

  • Communication

    • Convention

      • Like shared meaning in a public convention

      • Private

      • Local

        • Stock market

        • specialised

    • Deliberate

    • Explicit

Fax/computer

• handshake protocol

TCP/IP

• Transmission control protocol/internet protocol

• Two protocols

  • TCP makes packets

  • IP sends them to the right place

SMTP = Simple mail transfer protocol

MF Code = multiple frequency tones down phone lines

Connections pair form and content

representations are associations between a form and content

• seen

• heard

• felt

  • i.e. perceivable

• visual

  • scanning (as an input)

• touch

  • keyboard

• crossover

  • written music etc.

• Purple meths

  • No drink

• Simple white

  • Economy supermarket goods

• Beep at crossing

• Representations and meanings not fixed. Eg no smoking on a bin means no hot ash.

• Representation are context sensitive

  • eg. keystrokes in different programs

• Ambiguity is common in human communication

• computers need precise

  • eg. blue circle, word and pic, pic has more info, size etc.

    • Precision is granularity

      • Like a sieve, the smaller the holes, the less lost.

      • Digital and analogue

        • Information loss as info or variations between measurements not included.

• Ratio

  • 1:250,000 = one unit of measurement on paper will be 250,000 on the ground

  • The less the ratio, the greater the detail

• Redundancy

  • Meaning derived from part

  • Cam be beneficial or not

• Compression

  • Long to symbol shorter symbol/abbreviation

  • Or compressed/decompressed

    • Lossy

    • Lossless

  • eg #=the | = when eth

  • eg. eight of spades

    • eight appears four times

    • spades shown eight times

      • But helps readability

Precision depends on granularity

Representations without redundancy cannot be compressed

So: representations are not fixed. Choice depends on:

• Context sensitivity

• Ambiguity

• Precision

• Redundancy

  • Fit for purpose

• eg. in numbers, the position defines weight

  • Arithmetic is hard with roman numerals

  • Fit for purposes

    • Precision

      • eg. street maps

      • OS Maps

• Abstraction

  • Stripping out essential detail

    • London underground

  • reduce detail

  • reduce precision of detail

• Complex representational System

  • Made of smaller

  • eg. playing cards

    • Systematic relationship

      • eg. could add new 'rings' suit if you understand the system

    • Traffic signs

      • Circles =“ allows

      • Triangles =“ prohibit

    • Systematic build up = language

      • Can grow

    • i.e. simpler block are arranged according to pre-arranged rules an meanings are from arrangement of the parts.

SHARING AND FORMATS

• Format

  • detail levels

• Propriety

• public

• Standards

  • Deliberate

  • explicit

  • emerge

    • defacto eg. vhs

• Postscript = printing code standard

• Dependency = backwards compatible

• Conversion

  • Hard to be able to convert all

• Standardisation

  • slows production of new software

• Extensions

  • Mpeg =“ motion picture experts group

  • MP3 =“ Moving picture expert group audio layer 3 ?????

  • PNG =“ portable network graphic =“ lossless

Unit Three =“ Crossing the Boundary =“ Analogue Universe, Digital Worlds

• Computer is omnipresent tool

  • capture

  • Store present

  • manipulate

  • exchange

    • the interesting

• Two contrasting realms

  • Analogue

    • inhabit

  • Digital =“ inner of computer

    • Dangers

• We live in actual world

  • remember past world

  • imagine possible worlds

• Computers help us reach out and contact the world

• You take analogue to make a digital representation and cross the boundary into the computer

• Analogue

  • smooth qualities

    • moves up and down smoothly

    • Infinity possibilities between two points

• Discrete quantities

  • Change in s series of clear steps.

• Can have analogue and choose to make discrete eg. digital reading of a thermometer

• Computers can enhance our senses

• Infinite numbers, but only ten digits

  • Placed in columns for values

    • Every time a far left digit is ten times it's processor you add a new column

• 10x1= groups of tens

• 10¹ = same, the first column is 17 is a group of ten.

• 117 = the first column is a group of 100 (or 10 x 10 x1) or 10²

• = base 10 system/decimal

  • = can write down any number

• Octal = base 8

• 8¹ = groups of eight in left column.

• Binary in computer = differences in voltage in memory

  • computers hard as we have to lower ourselves to their level

Only binary

• Not base 10 in second columns

• New columns counts as groups of two

• So, 10=2, first column is one group of two and second nothing

• 11=3, one group of two and one group of one

• 100=4 etc.

• Eg. Column 6 is a group of 36. One in the six columns is six... I don't know. Yes. Col six is one is six and 2x2x2x2x2x1 (2⁵ = represents all the columns that went before it).

• So now column six is thirty two = base two system.

• Bit/binary digit = 0/1

• Byte = 8 bits

• so 11111111 = largest number that can be stored in a byte.

• 11111111 = 255

  • i.e. 1 group of 128

  • 1 of 64

  • 1 of 32

  • 1 of 16

  • 1 of 8

  • 1 of 4

  • 1 of 2

  • 1 of 1

  • = 255

binary arithmetic

• A word = 4 bytes

  • = the largest operation in a single computer

• Technically, analogue world is digital as all is quantum packets

Crossing the Boundary

• Standards to represent any analogue thing eg. numbers to all letters, upper and lower case, accents etc.

ASCII in '60's

Unicode later, inc, chines

carriage return

• Keyboard

  • Press

  • Electrical voltage to BIOS

  • basic in/out system

    • To binary

Pictures

• Bitmap copy as 1's and 2's.

• Each digit is a pixel.

• Bigger grid =“ better resolution

• Map @ 62>44=2728 bits to store

• Allocate more bits to each pixel

• = greyscale

• Remove of numbers to which a pixel can be mapped is the pixel amplitude.

Rendering decimal colour

• System corresponds to cones in waves which catch different red, green and blue wavelengths

• Al light we see corresponds to mixes of these three colours, so we have three numbers showing any particular colour.

• 255 0 0 = red, all red and no other colours

• 0 255 0 = green, (rgb)

• 255 255 255 = white

• Possible colours = 256x256x256=+16M

• CMYK = cyan magenta yellow and black, for printers

• Simper

  • Objects have code

  • Cartesian coordinates

  • = vector

  • (as opposed to bitmap/raster graphics)

  • Vector = scalable

    • Simplistic images only

• Moving pics

• 10 fps image joins afterimage and seems to move.

• Compression

• eg. giff reduces palette

Digital Still Cameras and Camcorders

• MPEG2 = dvd or to camera drive

• MPEG4 = flash, most shared over the internet.

• Charged Coupled Device

  • Cells like retina, that respond to light with tiny electrical charge, amount depends on colour and intensity =“ then like bitmap.

• Scanning

  • Raster scanning

    • Zig zag

      • Brightness (luminance)

      • Chrominance (colouring)

        • Measured set points over line and connected to a number

          • = bitmap

            • Resolution depends on scanning lines and measuring points

Sound and Music

• Sound, eg. tuning fork, vibrates ad the air around vibrates in sympathy with it. Height and low of vibration is wave, trough at bottom, peak at top, one peak to another is the cycle, amplitude is center of wave to peak (the length of one wave) and time passes left to right. umber of cycles in a fixed period of time = frequency. Amplitude of the wave (i.e. maximum vibration) is how loud the sound is. The frequency determines how high/low pitched.

• To digitize, i.e. put analogue into packets = pixels. Wave form = small time intervals Take readings at the time intervals (sampling). Number of times per second =“ sampling ract. apc = analogue to digital converter

• So put points across baseline and record where wave is at each one.

• So =“ digitizing pics = area packets. Sound = time packets

• Mapping of samples to numbers = quantization

  • Usually mapped to 16 bit numbers.

Summery

• digitize

  • Break target into parts

  • Map each with binary number

  • Can map anything analogue

    • and manipulate it

• Binary code has no semantics (the meaning attached to words and symbols)

  • Must regain meaning and go back

    • Output device

      • Arrange binary

      • Interpretation of code by device

Word = four bytes

• In a program, a word is an instruction in the cpu

  • so digital world manipulates the digital world

Meaning

• What is it as things cross back and forth across the boundary?

  • when does it attach and detach?

  • If line of text is about a picture,is the meaning different?

Devices

• Monitors

  • Cathode ray tube

    • Shoots electrons from back to screen in raster pattern. Front of tube has phosphorescent material that glows as electron hits it

  • lcd =“ molecules change orientation when electrical charge passed through

• Printer

  • Ink jet cmky.

  • Laser =“ fired over drum which is light sensitive and positively (?) charged so draws letters as electrical charges known as an electrostatic image. Then when pattern ready, drum coated in positively (?) charged dry powder toner which contains heat activated glue, and it clings to the negative charge

    • Digital output as a matrix

  • Plotter: analogue (eg. architect)

Summery

• Sampling

• Quantisation

• Programs

• Representation

Simulation

• models

• Can; be same size as world, so mus be a simplification based on abstraction; leave out everything that doesn't have a direct bearing on the model

  • General Graation Model???

    • World a separate grid

    • Each cell is column from ground to sky

    • At points going up:

      • temp

      • air

      • pressure humidity

        • = digitizing world

        • Same with space in grid

          • each point

            • Light

            • temp

      • add movement to see:

        • past

        • future

          • simulation

            • laws

              • all

              • everywhere

              • all the time

      • t1 t2 t3 = time intervals

Virtual worlds

• MUVE

• Immersion VR

• Mirror worlds: exact replicas being constantly updated

• artificial life: as binary code

• Telepresence = interact over a distance.