Hi-tech Trek

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A digital revolution is upon us. From laptops to mobile phones; washing machines to credit cards, computers are everywhere, even if sometimes they seem invisible. In the 2008 Christmas lectures, Professor Chris Bishop explores the science behind the latest innovations in computing and hunts for the answers to questions such as: Why do computers get smaller to run faster? How does a search engine find your favourite website in seconds from 60 billion pages? and How can I prove that I’m not a robot?!

So, what are you waiting for? Join Chris now on his quest to find the ultimate computer. You can explore key lecture themes, then really get under the surface of each topic by following the links to our fantastic science-packed activities.

Lecture 1: Breaking the speed limit

Fuelled for success – find out more about logic gates

Logic gates are the decision makers in electronic circuits. Three of the most common logic gates are AND, OR and NOT; each has its own rule, which is followed by switches either being on or off.

Imagine each logic gate as your school chef. They need you and your friend to eat all of your sprouts before you can get dessert.

AND – both you and your friend would need to eat the sprouts, otherwise no dessert.

OR – it would be OK if just one of you ate the sprouts – you'd both still get dessert.

NOT – you'd have to do the opposite of what you were told. This means that no one would have to eat sprouts but you'd still get chocolate pudding!

Revivatron – how to build a speedy microprocessor

Microprocessors are the brains of a computer. Their components work together to ensure that your machine can tackle anything you throw at it, from writing essays to playing games to instant messaging.

The four main components are:

  • Data exchange – this allows the microprocessor to communicate with the rest of the computer, fetching data from the main memory and passing out the results of the core's calculations.
  • Processing core – does all the number crunching.
  • Core memory – reading data off the main memory is very slow. Each core has its own mini memory stash to keep crucial data close at hand and quickly accessed.
  • Shared memory – a larger mini memory stash, which can be shared by multiple cores.

Breaking the speed limit activities to try at home (internal link – new window)

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Lecture 2: Chips with everything

Vigsaw – touch screen technologies

How about a special table with a display screen on top that is able to sense when an object has been placed on it, or when you've touched it with your fingers? This is one futuristic technology called 'surface computing' that's already with us.

Imagine being able to lay your digital camera on top of the table and see it automatically download all the photos and show them across the display surface.

Just by touching the photos displayed on the table, you can move them around to pass over to a friend, zoom in, or even drag them over to your mobile phone to automatically save them!

Gadget-go-round – Which is better? A washing machine or a mobile phone?

Many everyday objects around us are incorporating more and more computer technology, even in places you’d never have thought. All of the household objects in this game contain computer chips. Does a washing machine or a flat screen TV have more processing power? Does a digital camera or an MP3 player tend to have more storage memory? Which is more power-hungry: a games console or a laptop?

To win this contest you'll need to think carefully about what these objects might need in order to work! For example, did you know a pocket MP3 player can contain several different computer chips? But how does the total processing power compare to other household items...?

Chips with everything activities to try at home (internal link – new window)

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Lecture 3: Ghost in the machine

'ear 'ear – how to fit an orchestra onto your MP3 player

Many people like to save music to their computer, or download tracks from online stores. In order for the tracks to download faster and take up less space on your hard disk they can be 'compressed'. For example, a CD album can be compressed using the MP3 format to only about a tenth of the size, and most people won't be able to hear the difference.

Some compression methods allow the original music to be recovered perfectly, but these can only make the file size a little bit smaller. Other methods can achieve greater levels of compression by losing information (they’re called 'lossy'), but can spoil the sound of the music.

Stop bugging me – computer programming tips and tricks

Behind every piece of software, website and computer game lies lines and lines of programming code. Each line of code contains an instruction for what the computer should do. These instructions have to be very precise.

Rather than 'When I click a button, would you mind awfully moving forwards one space', computers like simple commands such as: OnClick: Move forward 1

Ghost in the machine activities to try at home (internal link – new window)

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Lecture 4: Untangling the web

Snap – learn about the secrets of visual cryptography

Visual cryptography is a way of encrypting a picture to protect the information it shows. The black and white pixels that make up the picture are randomly split into two halves. This is done in such a way that the picture only reappears if the two halves are exactly lined up on top of each other. Pixels either overlap (to make a grey-white) or complement each other (to make black).

The great thing about visual cryptography is that both halves on their own just look like black and white fuzz, so if someone intercepts one half of the picture, there's no way they can tell what it's supposed to be (unless of course you're sending a picture of black and white fuzz!)

Monkey business – sharing information peer to peer

The traditional way of receiving files through the internet, when downloading music for example, is to ask a central computer called a server to send you all the parts you need. But if lots of people all want files at the same time, the server can get overloaded and everything slows down. A different approach is called peer-to-peer file sharing, whereby the server sends out parts of the file to a few different computers that request it, but then they share amongst themselves. This way, everybody gets all the parts of a file they need, without the server getting clogged up.

Untangling the web activities to try at home (internal link – new window)

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Lecture 5: Digital intelligence

Pyroparrot – the science behind predictive texting

The order of letters in a word isn't random, and some combinations occur much more frequently than others. For example, Q is almost always followed by U, T-H is likely to have a vowel next, and Z never follows X. If the letters so far spell out a real word, the next character is likely to be a space. Computer software can use these probabilities to suggest the next letter as you write, like the predictive text messaging on your mobile phone but much more sophisticated. Technology like this can help on small handheld computers or if you are disabled and can’t use a keyboard.

Are you human? – advances in machine learning

Although computers are very fast at simple calculations, they only work if they have been told exactly what to do – by running software written by clever computer programmers. But did you know that computers really struggle to recognise things like cats and dogs? A cutting-edge area of research called 'machine vision' tries to solve this problem.

The computer is programmed to find features like the outline of different objects and to recognise patterns or colour combinations. If computers were able to process vision like a human, it would be really useful for spotting tumours in medical scans or even as an autopilot for your car!

Digital intelligence activities to try at home (internal link – new window)

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Order DVD

A DVD of all five of this year’s Christmas Lectures will be available from March 2009. Pre-order your copy now by visiting the 2008 DVD order page

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