CS4FN Advent – Day 20: where’s it @? Gift tags and internet addresses

We’re doing a post a day for Advent 2021 with a mix of new articles and ones from our extensive CS4FN (Computer Science For Fun) archives. CS4FN has been going since 2005 and we have hundreds of articles to choose from, on a huge variety of topics.

We hope you’re enjoying our daily posts and if you’ve missed any just scroll to the end to catch up with the full set.

Today is Day 20 of the CS4FN Christmas Computing Advent Calendar and the picture today is a gift tag, which is a way of addressing a gift. So today’s post is all about internet addresses.

A festive gift-tag

1. Wh@ a history!

by Peter McOwan, QMUL. This article originally appeared on the CS4FN website.

The @ symbol of your email address first appeared in the Middle Ages. Monks would translate and copy books, but there were often problems when the bookbinders put the pages together in the wrong order. To get round this the monks repeated the last line of each page on the top of the next. This was very laborious so they came up with quick abbreviations even for small but common words like “ad”. It is Latin for “at” or “to”, and the medieval monks sometimes wrote ‘d’ like a mirrored ‘6’. The @ symbol was born. Morse code was updated in 2003 with a special code for @ (•–•-•) so that people could send email addresses by Morse code!

 

2. La Chiocchiola pasta

by Jo Brodie, QMUL.

In 1999 an Italian pasta company decided to create a pasta shape to celebrate the humble @ symbol. “@” had already been in use in email addresses for several decades (since the 1960s) but was becoming more popular as the use of email expanded and spread beyond businesses, the military and academia (universities etc).

@ symbol image by Pete Linforth from Pixabay

The ‘cyberpasta’ was called “La Chiocchiola” which is the Italian word for snail and you can probably see why they use that word to describe the similarly-shaped symbol. The pasta was awarded a prize from the National Museum of Pasta in Rome where samples of the @ shape were displayed and also given away free. Thanks to the Internet Archive you can even see a copy of the English language version of the pasta company’s website from May 1999 (only a few months after Google was founded).

 

3. Do @ me

by Jo Brodie, QMUL.

We can thank Ray Tomlinson for the earliest use of the @ symbol to separate an individual computer use from the network they’re using, and to act as an addressing system. Millions of people use Gmail and have an email address ending in gmail.com but (generally) each one gets only their own messages thanks to whatever unique set of letters and numbers is in front of the @. He chose the symbol because it’s a character that never appears in people’s name so could be used as a marker to separate the person from the machine or network. This neat and simple solution made it possible for people to send email anywhere in the world.

Further reading

How does email work? (31 May 2021) Namecheap – a detailed guide to what happens after you press SEND.

 

How telephone calls used to be connected (From Wikimedia Commons).

 

4. The internet’s address book

by Jo Brodie, QMUL.

Type any web address like www.google.com into a browser address bar, press enter and that address is instantly converted behind the scenes into a series of numbers.

The web address is known as a domain name and it’s an easy to remember version of the website’s address. The series of numbers is called the IP address (which stands for Internet Protocol). The human-readable domain name is translated into the machine-readable IP address by the DNS (Domain Name System) which acts as the internet’s ‘address book’. A DNS server can ‘look up’ the domain name in a list and find the corresponding IP address.

Everything that is connected to the internet has its own IP address including smartphones, laptops, networked printers etc and IP addresses have been in use for decades, helping direct traffic around the internet. We don’t usually see these IP addresses (we don’t generally need to!) but they look like a string of digits chunked into 4 groups, for example 198.51.100.0.

Each of those four ‘chunks’ is actually represented by an 8-digit binary number (or ‘octet’), so the range of each 8-digit octet goes from 00000000 (zero) to 11111111 (255). As 11111111 is the largest 8-digit binary number possible, no chunk can be above 255.

  • There are four octets (each containing 8 digits) in an IP address
  • Each of the octets can range from 00000000 to 11111111 (represented by 0 to 255)
  • Every IP address is therefore made up of a string of 32 (4 octets x 8 digits) ones or zeroes in a particular combination.

This means that there are 232 (two to the power of 32) possible IP address combinations giving an enormous number of over 4 billion addresses (which can be written as 4,294,967,296 or 4.294967296 × 109). Note that it’s “2” because in binary it’s either a 1 or a 0.

You might think that this would give us plenty of addresses to be going on with, but no! It was predicted that as more devices were connected to the internet, as its use expanded, we’d eventually start to run out and sure enough in 2011 we actually began to run out of these 32-bit addresses. Fortunately a new internet protocol (version 6, so it’s IPv6) was developed that uses 128 bits, which means there’s now a possible 2128 variations, giving an even more enormous number of 3.402823669 x 1038 addresses. Well, that should keep us going for a while!

 

Example IP address (from Wikimedia Commons).

 

5. Cracking a smart meter

by Paul Curzon, QMUL. This article originally appeared on the CS4FN website.

Smart electricity meters are clever meters that are connected to the Internet so they can send data back to the power company about your minute by minute electricity usage for billing purposes. If burglars could get hold of data from a smart electricity meter they can tell whether you are in or not (See Smart meter snooping).

How could anyone other than the power company get the data though? A German research team led by Dario Carluccio decided to see if it was possible. They have shown that the data from at least one kind of smart meter can be intercepted by anyone with the right software. Data needs to be encrypted – transmitted using an uncrackable code – to be safe from prying eyes. For the smart meter they examined that wasn’t done securely. They could not only intercept the data, they could even tamper with what was sent back to the company, which could be used, for example to lower their bills. All you needed was what is known as the ‘MAC address‘ of the smart meter. A MAC address is just the unique network name that a computer uses to identify itself- all computers connecting to the Internet have one. Unless special security is used any computer can pretend it is some other computer just by using the target computer’s MAC address when asked to identify itself. With the smart meter to send bogus data you essentially just need to get another computer to use the smart meter’s MAC address before sending data. The researchers demonstrated this by change the electricity usage data in a way that made the graph of peaks and troughs of usage read the message “U have been hacked”!

(A device’s MAC address is used locally, to identify it to your home broadband whereas the IP address identifies your device to the internet so that it can receive information from anyone, anywhere).

This creation of this post was funded by UKRI, through grant EP/K040251/2 held by Professor Ursula Martin, and forms part of a broader project on the development and impact of computing.

 

6. Previous Advent Calendar posts

CS4FN Advent – Day 1 – Woolly jumpers, knitting and coding (1 December 2021)

 

CS4FN Advent – Day 2 – Pairs: mittens, gloves, pair programming, magic tricks (2 December 2021)

 

CS4FN Advent – Day 3 – woolly hat: warming versus cooling (3 December 2021)

 

CS4FN Advent – Day 4 – Ice skate: detecting neutrinos at the South Pole, figure-skating motion capture, Frozen and a puzzle (4 December 2021)

 

CS4FN Advent – Day 5 – snowman: analog hydraulic computers (aka water computers), digital compression, and a puzzle (5 December 2021)

 

CS4FN Advent – Day 6 – patterned bauble: tracing patterns in computing – printed circuit boards, spotting links and a puzzle for tourists (6 December 2021)

 

CS4FN Advent – Day 7 – Computing for the birds: dawn chorus, birds as data carriers and a Google April Fool (plus a puzzle!) (7 December 2021)

 

CS4FN Advent – Day 8: gifts, and wrapping – Tim Berners-Lee, black boxes and another computing puzzle (8 December 2021)

 

CS4FN Advent – Day 9: gingerbread man – computing and ‘food’ (cookies, spam!), and a puzzle (9 December 2021)

 

CS4FN Advent – Day 10: Holly, Ivy and Alexa – chatbots and the useful skill of file management. Plus win at noughts and crosses – (10 December 2021)

 

CS4FN Advent – Day 11: the proof of the pudding… mathematical proof (11 December 2021)

 

CS4FN Advent – Day 12: Computer Memory – Molecules and Memristors – (12 December 2021)

 

CS4FN Advent – Day 13: snowflakes – six-sided symmetry, hexahexaflexagons and finite state machines in computing (13 December 2021)

 

CS4FN Advent – Day 14 – Why is your internet so slow + a festive kriss-kross puzzle (14 December 2021)

 

CS4FN Advent – Day 15 – a candle: optical fibre, optical illusions (15 December 2021)

 

CS4FN Advent – Day 16: candy cane or walking aid: designing for everyone, human computer interaction (16 December 2021)

 

CS4FN Advent – Day 17: reindeer and pocket switching (17 December 2021)

 

CS4FN Advent – Day 18: cracker or hacker? Cyber security(18 December 2021)

 

CS4FN Advent – Day 19: jingle bells or warning bells? Avoiding computer scams (19 December 2021)

 

CS4FN Advent – Day 20: where’s it @? Gift tags and internet addresses – this post

 

 

 

CS4FN Advent – Day 19: jingle bells or warning bells? Avoiding computer scams

It’s Day 19 of the CS4FN Christmas Computing Advent Calendar. Every day throughout Advent we’ll be doing our best to publish a computing-themed post that relates to the picture on the advent calendar’s door. If you’d like to judge how well we’ve done please scroll to the end of this post where we have a full list of our attempts on Days 1 to 18.

Yesterday’s picture was a Christmas cracker, so our theme was cyber security (cracking and hacking into computers). We’re staying quite close with that theme with today’s jingle bells – bells also put me in mind of warnings, and today’s post is about computing scams. So keep your bells pealed and your eyes peeled 🙂 Learn about scams and tell other people about them so they can avoid them too.

 

Jingle bells, warning you of festive scams

Gone Phishing

Fake emails or text messages asking for bank details including passwords is known in the trade as ‘Phishing‘ – it’s an example of social engineering, in which someone tries to manipulate someone else into giving away information. Like fishing the criminals scatter lots of bait and once in a while someone bites on the hook and replies. Criminals have even created fake Internet banking sites, direct copies of the real sites, in an attempt to scam customers’ details. This type of crime would never have been possible before computers. Few criminals would have the ability or funds to build a fake copy of your bank in the high street, but they can write programs to simulate them online.

Phishing image by mohamed Hassan from Pixabay

 

1. A gift for scammers

Scammers love Christmas. It’s the perfect time of year to try and extract money or information (or both) from frazzled, busy and distracted Christmas shoppers.

“We’re sorry we missed you”

This popular phishing scam will come via text, saying that there’s a problem with delivering your item and you need to pay some small amount of money to rearrange delivery.

In the run up to Christmas so many people are expecting deliveries so this scam is successful because even if only a small percent of people fall for it that’s still a lot of people. The text message will contain a link that looks like it’s for the genuine web address of a delivery company where you might already have an account. But… the link’s taken you to the scammer’s replica website in the hope that you hand over your login information and possibly your bank card details to pay. The scam is quite subtle as once you fill in your details and press send you are then redirected to the genuine company’s website, so it’s easy to miss what’s happened at first.

How to stay safe: were you expecting this text message? If not, be alert. Look at the link carefully – does it seem correct? If it seems fake you can forward the message from any mobile phone to 7226 (which spells SPAM on your keypad). Learn about scams (See further reading) and tell people about them so they know what to watch out for.

See how well you do on Google’s Phishing Quiz (you can make up a fake email address to use) – some are genuine, some are trying to steal information. Can you spot which is which?

Further reading

Phishing: Spot and report scam emails, texts, websites and calls, from the National Cyber Security Centre

 

2. Logging on, to your computer

Some phishing attempts are a bit more involved. You might get a phone call from someone claiming that ‘bad people’ have ‘got into your internet’ and you need to take immediate action to prevent being cut off. Sometimes the scammers pretend to be from a well-known computer company (such as Microsoft) or from the company that provides you with your broadband internet.

Fraud image by mohamed Hassan from Pixabay

Sometimes they’ll try and engage you in conversation – this is ‘social engineering’. This is a to try and gain your trust while keeping you anxious that something has gone wrong and which they are going to help you with. They may even use some tricks to convince you they’re legitimate. If you use a Windows computer they might ask you to open up the Event Viewer and count the errors, suggesting that there’s a problem (in reality it’s all pretty normal and harmless).

The next thing they might want you to do is to download some ‘desktop sharing’ software onto your computer. The software is real enough (and can be used genuinely to help people) but in this case they want to be able to access your computer and cause havoc. What they probably want to do is see if you have online banking (so they can steal your money) or they might delete some important files and say they’ll give them back only if you pay them. Don’t let them in!

How to stay safe: you can just hang up! Definitely don’t download any software, don’t visit any links they suggest you go to and don’t give them any information.

Further reading

Remote access scams: the call that could wipe out your life savings (Nov 2020) Which?
Who scams the scammers? Meet the scambaiters (October 2021) The Observer

 

3. And you are…?

This ‘friend in need’ scam will likely come via WhatsApp. Someone pretending to be a family member or friend gets in touch claiming they’re contacting you from a new phone after their old one was lost or stolen. They then claim they need money for some urgent reason and ask you to send them some via online banking.

This scam relies on people’s kindness and goodwill, and not wanting to be seen to be stingy or unhelpful, but sadly it causes thousands of pounds to be stolen and it’s often very difficult to recover that money.

How to stay safe: be suspicious. Try and contact your friend / family member in another way to check it’s really them. Or do a bit of social engineering yourself – make up something and ask them about it. Rather than admit they don’t know about it they’ll probably answer ‘yes’ and give themselves away!

Further reading

‘We lost festive savings in family WhatsApp scam’ (11 November 2021) BBC News
‘Friend in need’ message scam costs victims almost £50,000 in three months (24 November 2021) Action Fraud

 

Previous Advent Calendar posts

CS4FN Advent – Day 1 – Woolly jumpers, knitting and coding (1 December 2021)

 

CS4FN Advent – Day 2 – Pairs: mittens, gloves, pair programming, magic tricks (2 December 2021)

 

CS4FN Advent – Day 3 – woolly hat: warming versus cooling (3 December 2021)

 

CS4FN Advent – Day 4 – Ice skate: detecting neutrinos at the South Pole, figure-skating motion capture, Frozen and a puzzle (4 December 2021)

 

CS4FN Advent – Day 5 – snowman: analog hydraulic computers (aka water computers), digital compression, and a puzzle (5 December 2021)

 

CS4FN Advent – Day 6 – patterned bauble: tracing patterns in computing – printed circuit boards, spotting links and a puzzle for tourists (6 December 2021)

 

CS4FN Advent – Day 7 – Computing for the birds: dawn chorus, birds as data carriers and a Google April Fool (plus a puzzle!) (7 December 2021)

 

CS4FN Advent – Day 8: gifts, and wrapping – Tim Berners-Lee, black boxes and another computing puzzle (8 December 2021)

 

CS4FN Advent – Day 9: gingerbread man – computing and ‘food’ (cookies, spam!), and a puzzle (9 December 2021)

 

CS4FN Advent – Day 10: Holly, Ivy and Alexa – chatbots and the useful skill of file management. Plus win at noughts and crosses – (10 December 2021)

 

CS4FN Advent – Day 11: the proof of the pudding… mathematical proof (11 December 2021)

 

CS4FN Advent – Day 12: Computer Memory – Molecules and Memristors – (12 December 2021)

 

CS4FN Advent – Day 13: snowflakes – six-sided symmetry, hexahexaflexagons and finite state machines in computing (13 December 2021)

 

CS4FN Advent – Day 14 – Why is your internet so slow + a festive kriss-kross puzzle (14 December 2021)

 

CS4FN Advent – Day 15 – a candle: optical fibre, optical illusions (15 December 2021)

 

CS4FN Advent – Day 16: candy cane or walking aid: designing for everyone, human computer interaction (16 December 2021)

 

CS4FN Advent – Day 17: reindeer and pocket switching (17 December 2021)

 

CS4FN Advent – Day 18: cracker or hacker? Cyber security(18 December 2021)

 

CS4FN Advent – Day 19: jingle bells or warning bells? Avoiding computer scams (19 December 2021) – this post

 

 

 

CS4FN Advent – Day 18: cracker or hacker? Cyber security

It’s Day 18 of the CS4FN Christmas Computing Advent Calendar and also the last day for 2nd class Christmas post to reach people in the UK, but you’ve got until Tuesday the 21st for first class post.

We’ve been posting a computing-themed article linked to the picture on the ‘front’ of the advent calendar for the last 17 days and today is no exception. The picture is of a Christmas cracker so today’s theme is going to be computer hacking and cracking – all about Cyber Security.

If you’ve missed any of our previous posts, please scroll to the end of this one where we have a full list.

A cracker, ready to pop

 

The terms ‘cracker’ and ‘hacker’ are often used interchangeably to refer to people who break into computers though generally the word hacker also has a friendlier meaning – someone who uses their skills to find a workaround or a solution (e.g. ‘a clever hack’) whereas a cracker is probably someone who shouldn’t be in your system and is up to no good. Both people can use very similar skills though – one is using them to benefit others, the other to be benefit themselves.

We have an entire issue of the CS4FN magazine all about Cyber Security – it’s issue 24 and is called ‘Keep Out’ but we’ll let you in to read it. All you have to do is click on this very secret link, then click on the magazine’s front cover to download the PDF. But don’t tell anyone else…

Both the articles below were originally published in the magazine as well as on the CS4FN website.

 

Piracy on the open Wi-fi

by Jane Waite, Queen Mary University of London. This article was originally published on the CS4FN website.

You arrive in your holiday hotel and ask about Wi-Fi. Time to finish off your online game, connect with friends, listen to music, kick back and do whatever is your online thing. Excellent! The hotel Wi-Fi is free and better still you don’t even need one of those huge long codes to access it. Great news, or is it?

Pirate flag and wifi picture adapted from an image by OpenClipart-Vectors from Pixabay

You always have to be very cautious around public Wi-Fi whether in hotels or cafes. One common attack is for the bad guys to set up a fake Wi-Fi with a name very similar to the real one. If you connect to it without realising, then everything you do online passes through their computer, including all those user IDs and passwords you send out to services you connect to. Even if the passwords they see are encrypted, they can crack them offline at their leisure.

Things just got more serious. A group has created a way to take over hotel Wi-Fi. In July 2017, the FireEye security team found a nasty bit of code, malware, linked to an email received by a series of hotels. The malware was called GAMEFISH. But this was no game and it certainly had a bad, in fact dangerous, smell! It was a ‘spear phishing’ attack on the hotel’s employees. This is an attack where fake emails try to get you to go to a malware site (phishing), but where the emails appear to be from someone you know and trust.

Once in the hotel network, so inside the security perimeter, the code searched for the machines running the hotel’s Wi- Fi and took them over. Once there they sat and watched, sniffing out passwords from the Wi-Fi traffic: what’s called a man-in-the-middle attack.

The report linked the malware to a very serious team of Russian hackers, called FancyBear (or APT28), who have been associated with high profile attacks on governments across the world. GAMEFISH used a software tool (an ‘exploit’) called EternalBlue, along with some code that compiled their Python scripts locally, to spread the attack. Would you believe, EternalBlue is thought to have been created by the US Government’s National Security Agency (NSA), but leaked by a hacker group! EternalBlue was used in the WannaCry ransomware too. This may all start to sound rather like a farfetched thriller but it is not. This is real! So think before you click to join an unsecured public Wi-Fi.

 

 

Just between the two of us: mentalism and covert channels

by Peter W McOwan, Queen Mary University of London. This article was originally published on the CS4FN website.

Secret information should stay secret. Beware ‘covert channels’ though. They are a form of attack where an illegitimate way of transferring information is set up. Stopping information leaking is a bit like stopping water leaking – even the smallest hole can be exploited. Magicians have been using covert channels for centuries, doing mentalism acts that wow audiences with their ‘telepathic’ powers.

Illusionist image by Andrei Cássia from Pixabay

The secret codes of Mentalism

In the 1950’s Australian couple Sydney and Lesley Piddington took the entertainment world by storm. They had the nation perplexed, puzzled and entertained. They were seemingly able to communicate telepathically over great distances. It all started in World War 2 when Sydney was a prisoner of war. To keep up morale, he devised a mentalism act where he ‘read the minds’ of other soldiers. When he later married Lesley they perfected the act and became an overnight sensation, attracting BBC radio audiences of 20 million. They communicated random words and objects selected by the audience, even when Lesley was in a circling aeroplane or Sydney was in a diving bell in a swimming pool. To this day their secret remains unknown, though many have tried to work it out. Perhaps they used a hidden transmitter. After all that was fairly new technology then. Or perhaps they were using their own version of an old mentalism trick: a code to transmit information hidden in plain sight.

Sounds mysterious

Sydney had a severe stutter, and some suggested it was the pauses he made in words rather than the words themselves that conveyed the information. Using timing and silence to code information seems rather odd, but it can be used to great effect.

In the phone trick ‘Call the wizard’, for example, a member of the audience chooses any card from a pack. You then phone your accomplice. When they answer you say “I have a call for the wizard”. Your friend names the card suits: “Clubs … spades … diamonds … hearts”. When they reach the suit of the chosen card you say: “Thanks”.

Your phone friend now knows the suit and starts counting out the values, Ace to King. When they reach the chosen card value you say: “Let me pass you over”. Your accomplice now knows both suit and value so dramatically reveals the card to the person you pass the phone to.

This trick requires a shared understanding of the code words and the silence between them. When combined with the background count, information is passed. The silence is the code.

Timing can similarly be used by a program to communicate covertly out of a secure network. Information might be communicated by the time a message is sent rather than its contents, for example

Codes on the table

Covert channels can be hidden in the existence and placement of things too. Here’s another trick.

The receiving performer leaves the room. A card is chosen from a pack by a volunteer. When the receiver arrives back they are instantly able to tell the audience the name of the card. The secret is in the table. Once the card has been selected, pack and box are replaced on the table. The agreed code might be:

If the box is face up and its flap is closed: Clubs.
If the box is face up and its flap is open: Spades.
If the box is face down and its flap is closed: Diamonds.
If the box is face down and its flap is open: Hearts.

That’s the suits taken care of. Now for the value. The performers agree in advance how to mentally chop up the card table into zones: top, middle and bottom of the table, and far right, right, left and far left. That’s 3 x 4 unique locations. 12 places for 12 values. The pack of cards is placed in the correct pre-agreed position, box face up or not, flap open or closed as needed. What about the 13th possibility? Have the audience member hold their hand out flat and leave the cards on it for them to ‘concentrate’ on.

Again a similar idea can be used as a covert channel to subvert a security system: information might be passed based on whether a particular file exists or not, say.

Making it up as you go along

These are just a couple of examples of the clever ideas mentalists have used to amaze and entertain audiences with feats of seemingly superhuman powers. Our cs4fn mentalism portal has more. Some claim they have the powers for real, but with two dedicated performers and a lot of cunning memory work, it’s often hard to decipher performers’ methods. Covert channels can be similarly hard to spot.

Perhaps the Piddingtons secret was actually a whole range of different methods. Just before she died Lesley Piddington is said to have told her son, “Even if I wanted to tell you how it was done, I don’t think I would be able”. How ever it was done, they were using some form of covert channel to cement their place in magic history. As Sydney said at the end of each show “You be the judge”.

 

Answers to yesterday’s bumper puzzle compendium

CS4FN Christmas Computing Advent Calendar – Answers

 

Previous Advent Calendar posts

CS4FN Advent – Day 1 – Woolly jumpers, knitting and coding (1 December 2021)

 

CS4FN Advent – Day 2 – Pairs: mittens, gloves, pair programming, magic tricks (2 December 2021)

 

CS4FN Advent – Day 3 – woolly hat: warming versus cooling (3 December 2021)

 

CS4FN Advent – Day 4 – Ice skate: detecting neutrinos at the South Pole, figure-skating motion capture, Frozen and a puzzle (4 December 2021)

 

CS4FN Advent – Day 5 – snowman: analog hydraulic computers (aka water computers), digital compression, and a puzzle (5 December 2021)

 

CS4FN Advent – Day 6 – patterned bauble: tracing patterns in computing – printed circuit boards, spotting links and a puzzle for tourists (6 December 2021)

 

CS4FN Advent – Day 7 – Computing for the birds: dawn chorus, birds as data carriers and a Google April Fool (plus a puzzle!) (7 December 2021)

 

CS4FN Advent – Day 8: gifts, and wrapping – Tim Berners-Lee, black boxes and another computing puzzle (8 December 2021)

 

CS4FN Advent – Day 9: gingerbread man – computing and ‘food’ (cookies, spam!), and a puzzle (9 December 2021)

 

CS4FN Advent – Day 10: Holly, Ivy and Alexa – chatbots and the useful skill of file management. Plus win at noughts and crosses – (10 December 2021)

 

CS4FN Advent – Day 11: the proof of the pudding… mathematical proof (11 December 2021)

 

CS4FN Advent – Day 12: Computer Memory – Molecules and Memristors – (12 December 2021)

 

CS4FN Advent – Day 13: snowflakes – six-sided symmetry, hexahexaflexagons and finite state machines in computing (13 December 2021)

 

CS4FN Advent – Day 14 – Why is your internet so slow + a festive kriss-kross puzzle (14 December 2021)

 

CS4FN Advent – Day 15 – a candle: optical fibre, optical illusions (15 December 2021)

 

CS4FN Advent – Day 16: candy cane or walking aid: designing for everyone, human computer interaction (16 December 2021)

 

CS4FN Advent – Day 17: reindeer and pocket switching (17 December 2021)

 

 

CS4FN Advent – Day 18: cracker or hacker? Cyber security(18 December 2021) – this post

 

 

 

CS4FN Advent – Day 17: pocket-switching networked reindeer

Gosh, Christmas is just around the corner! It’s Day 17 of the CS4FN Christmas Computing Advent Calendar and we’ve posted a blog post every day since 1 December, and you can catch up with all of those posts at the end of this one. We’ll publish a new post every day during Advent, so check back each day.

In doing this we’re also celebrating CS4FN’s own history, revisiting some of our older posts and articles. CS4FN began in 2005 and was created by Profs Peter McOwan and Paul Curzon at QMUL to introduce the subject of computing in a fun way, highlighting the joy of creativity and thinking about things in interesting ways.

If you know a computing schoolteacher in the UK who might like FREE copies of our CS4FN magazine for their classroom please ask them to subscribe.

Today’s advent calendar picture is of a reindeer and, if you’ve been following our advent calendar, you probably won’t be too surprised that I’ve managed to find a CS4FN article which features reindeer!

A reindeer with a red and shiny nose

 

 

Even the dolphins use pocket switched networks!

by Paul Curzon, QMUL. This article, from 2007, originally appeared on the CS4FN website.

Email, texting, Instant Messaging, Instant response…one of the things about modern telecoms is that they fuel our desire to “talk” to people anytime, anywhere, instantly. The old kind of mail is dismissed as “snail mail”. A slow network is a frustrating network. So why would anyone be remotely interested in doing research into slow networks? Professor Jon Crowcroft of the University of Cambridge and his team are, and his kind of network could be the network of the future. The idea is already being used by the dolphins (not so surprising I suppose given according to Douglas Adams’ “The HitchHiker’s Guide to the Galaxy” they are the second most intelligent species on Earth…after the mice).

From node to node

Traditional networks rely on having lots of fixed network “nodes” with lots of fast links between them. These network nodes are just the computers that pass on the messages from one to the other until the messages reach their destinations. If one computer in the network fails, it doesn’t matter too much because there are enough connections for the messages to be sent a different way.

Network connections image by Gerd Altmann from Pixabay

There are some situations where it is impractical to set up a network like this though: in outer space for example. The distances are so far that messages will take a long time – even light can only go so fast! Places like the Arctic Circle are another problem: vast areas with few people. Similarly, it’s a problem under the sea. Signals don’t carry very well through water so messages, if they arrive at all, can be muddled. After major disasters like Hurricane Katrina or a Tsunami there are also likely to be problems.

It is because of situations like these that computer scientists started thinking about “DTNs”. The acronym can mean several similar things: Delay Tolerant Networks (like in space the network needs to cope with everything being slow), Disruption Tolerant Networks (like in the deep sea where the links may come and go) or Disaster Tolerant Networks (like a Tsunami where lots of the network goes down at once). To design networks that work well in these situations you need to think in a different way. When you also take into account that computers have gone mobile – they no longer just sit on desks but are in our pockets or handbags, this leads to the idea of a “ferrying network” or as Jon Crowcroft calls them: “Pocket Switched Network”. The idea is to use the moving pocket computers to make up a completely new kind of network, where some of the time messages move around because the computers carrying them are moving themselves, not because the message itself is moving. As they move around they pass near other computers and can exchange messages, carrying a message on for someone else until it is near another computer it can jump to.

From Skidoo to you

How might such networks be useful in reality? Well one already exists for the reindeer farmers in the Arctic Circle. They roam vast icy wastelands on skidoos, following their reindeer. They are very isolated. There are no cell phone masts or internet nodes and for long periods they do not meet other people at all. The area is also too large to set up a traditional network cheaply. How can they communicate with others?

Aurora Northern Lights image by Noel Bauza from Pixabay

They have set up a form of pocket switched network. Each carries a laptop on their skidoo. There is also a series of computers sitting in tarns spread around the icy landscape. When the reindeer farmers want a service, like delivering a message, the laptop stores the request until they pass within range of one of the other computers perhaps on someone else’s skidoo. The computer then automatically passes the message on. The new laptop takes the message with it and might later pass a tarn, where the message hops again then waits till someone else passes by heading in the right direction. Eventually it makes a hop to a computer that passes within range of a network point connected to the Internet. It may take a while but the mail eventually gets through – and much faster than waiting for the farmer to be back in net contact directly.

Reindeer image by enny more from Pixabay

Chatting with Dolphins

Even the dolphins are in on the act. US scientists wanted to monitor coastal water quality. They hit on the idea of strapping sensors onto dolphins that measure the quality wherever they go. Only problem is dolphins spend a lot of time in deep ocean where the results can’t easily be sent back. The solution? Give them a normal (well dolphin adapted) cell phone. Their phone stores the results until it is in range of their service provider off the coast. By putting a receiver in the bays the dolphins return to most frequently, they can call home to pass on the data whenever there. The researchers encountered an unexpected problem though. The dolphin’s memory cards kept inexplicably filling up. Eventually they realised this was because the dolphins kept taking trips across the Atlantic where they came in range of the European cell networks. The European telecom companies, being a friendly bunch, sent lots of text messages welcoming these newly appeared phones to their network. The memory cards were being clogged up with “Hellos”!

Dolphins image by AJRPROJ from Pixabay

The Cambridge team are investigating how similar networks might best be set up and used for people on the move, even in busy urban environments. To this end they have designed a pocket switched network called Haggle. Using networks like Haggle, it might be possible to have peer-to-peer style networks that side-step the commercial networks. If enough people join in then messages could just hop from phone to phone, using bluetooth links say, as they passed near each other. They might eventually get to the destination without using any long distance carriers at all.

The more the merrier

With a normal network, as more people join the network it clogs up as they all try to use the same links to send messages at the same time. Some fundamental theoretical results have shown that with a pocket switched network, the capacity of the network can actually go up as more people join – because of the way the movement of the people constantly make new links.

Pocket switched networks are a bit like gases – the nodes of the network are like gas molecules constantly moving around. A traditional network is like a solid – all the molecules, and so nodes, are stationary. As more people join a gaseous network it becomes more like a liquid, with nodes still moving but bumping into other nodes more often. The Cambridge team are exploring the benefits of networks that can automatically adapt in this way to fit the circumstances: making phase transitions just like water boiling or freezing.

One of the important things to understand to design such a network is how people pass others during a typical day. Are all people the same when it comes to how many people they meet in a day? Or are there some people that are much more valuable as carriers of messages. If so those are the people the messages need to get to to get to the destination the fastest!

To get some hard data Jon and his students have been handing out phones. In one study a student handed out adapted phones at random on a Hong Kong street, asking that they be returned a fixed time later. The phones recorded how often they “met” each other before being returned. In another similar experiment the phones were given out to a large number of Cambridge students to track their interactions. This and other research shows that to make a pocket switched network work well, there are some special people you need to get the messages to! Some people meet the same people over and over, and very few others. They are “cliquey” people. Other more “special” people regularly cross between cliques – the ideal people to take messages across groups. Social Anthropology results suggest there are also some unusual people who rather than just networking with a few people, have thousands of contacts. Again those people would become important message carriers.

Busy pedestrians image by Brian Merrill from Pixabay

So the dolphins may be the “early adopters” of pocket switched networks but humans may be not far behind. If so it could completely change the way the telecom industry works…and if we (or the dolphins) ever do decide to head en-mass for the far reaches of the solar system, pocket switched networks like Haggle will really come into their own.

This article is based on a talk given by Jon Crowcroft at Queen Mary University of London in January 2007.

Missed one of our festive puzzles?

We’ve posted some Christmas kriss-kross and pixel puzzles (with the answers being posted the day later). If you’ve missed the earlier posts here’s a bumper edition of all of the Advent puzzles so far (and the answers will come tomorrow).

CS4FN Christmas Computing Advent Calendar – PUZZLES

You might also enjoy the Robot Reindeer race from the computer science department at Robert Gordon University in Aberdeen.

 

 

Previous Advent Calendar posts

CS4FN Advent – Day 1 – Woolly jumpers, knitting and coding (1 December 2021)

 

CS4FN Advent – Day 2 – Pairs: mittens, gloves, pair programming, magic tricks (2 December 2021)

 

CS4FN Advent – Day 3 – woolly hat: warming versus cooling (3 December 2021)

 

CS4FN Advent – Day 4 – Ice skate: detecting neutrinos at the South Pole, figure-skating motion capture, Frozen and a puzzle (4 December 2021)

 

CS4FN Advent – Day 5 – snowman: analog hydraulic computers (aka water computers), digital compression, and a puzzle (5 December 2021)

 

CS4FN Advent – Day 6 – patterned bauble: tracing patterns in computing – printed circuit boards, spotting links and a puzzle for tourists (6 December 2021)

 

CS4FN Advent – Day 7 – Computing for the birds: dawn chorus, birds as data carriers and a Google April Fool (plus a puzzle!) (7 December 2021)

 

CS4FN Advent – Day 8: gifts, and wrapping – Tim Berners-Lee, black boxes and another computing puzzle (8 December 2021)

 

CS4FN Advent – Day 9: gingerbread man – computing and ‘food’ (cookies, spam!), and a puzzle (9 December 2021)

 

CS4FN Advent – Day 10: Holly, Ivy and Alexa – chatbots and the useful skill of file management. Plus win at noughts and crosses – (10 December 2021)

 

CS4FN Advent – Day 11: the proof of the pudding… mathematical proof (11 December 2021)

 

CS4FN Advent – Day 12: Computer Memory – Molecules and Memristors – (12 December 2021)

 

CS4FN Advent – Day 13: snowflakes – six-sided symmetry, hexahexaflexagons and finite state machines in computing (13 December 2021)

 

CS4FN Advent – Day 14 – Why is your internet so slow + a festive kriss-kross puzzle (14 December 2021)

 

CS4FN Advent – Day 15 – a candle: optical fibre, optical illusions (15 December 2021)

 

CS4FN Advent – Day 16: candy cane or walking aid: designing for everyone, human computer interaction (16 December 2021)

 

 

CS4FN Advent – Day 17: reindeer and pocket switching (17 December 2021) – this post

 

 

 

CS4FN Advent – Day 16: candy cane or walking aid: designing for everyone, human computer interaction

Welcome to Day 16 of the CS4FN Christmas Computing Advent Calendar in which we’re posting a blog post every day in December until (and including) Christmas Day.

We’re celebrating the breadth of computing research and also the history of CS4FN, a project which has been distributing free magazines to subscribing UK schools since 2005 (ask your teacher to subscribe for next year’s magazine).

Today’s advent calendar picture is of a candy cane which made me think both of walking aids and of support sticks that alert others that the person using it is blind or visually impaired.

A white candy cane with green and red stripes.

We’ve worked with several people over the years to write about their research into making life easier for people with a variety of disabilities. Issue 19 of our magazine (“Touch it, feel it, hear it!”) focused on the DePiC project (‘Design Patterns for Inclusive Collaboration’) which included work on helping visually impaired sound engineers to use recording studio equipment, and you can read one of the articles (see ‘2. The Haptic Wave’) from that magazine below.

Our most recent CS4FN magazine (issue 27, called “Smart Health: decisions, decisions, decisions“) was about Bayesian mathematics and its use in computing, but one of those uses might be an app with the potential to help people with arthritis get medical support when they most need it (rather than having to wait until their next appointment) – download the magazine by clicking on its title and scroll to page 16 & 17 (p9 of the 11 page PDF). Our writing also supports the (obvious) case, that disabled people must be involved at the design and decision-making stages.

 

1. Design for All (and by All!)

by Paul Curzon, QMUL. This article was originally published on the CS4FN website.

Making things work for everyone

Designing for the disabled – that must be a niche market mustn’t it? Actually no. One in five people have a disability of some kind! More surprising still, the disabled have been the inspiration behind some of the biggest companies in the world. Some of the ideas out there might eventually give us all super powers.

Just because people have disabilities doesn’t mean they can’t be the designers, the innovators themselves of course. Some of the most innovative people out there were once labelled ‘disabled’. Just because you are different doesn’t mean you aren’t able!

Where do innovators get their ideas from? Often they come from people driven to support people currently disadvantaged in society. The resulting technologies then not only help those with disabilities but become the everyday objects we all rely on. A classic example is the idea of reducing the kerbs on pavements to make it possible for people in wheelchairs to get around. Turns out of course that they also help people with pushchairs, bikes, roller-blades and more. That’s not just a one-off example, some of the most famous inventors and biggest companies in the world have their roots in ‘design for all’.

Designing for more extreme situations pushes designers into thinking creatively, thinking out of the box. That’s when totally new solutions turn up. Designing for everyone is just a good idea!

2. Blind driver filches funky feely sound machine! The Haptic Wave

by Jane Waite, QMUL. This article was originally published on the CS4FN website.

The blind musician Joey Stuckey in his recent music video commandeers then drives off in a car, and yes he is blind. How can a blind person drive a car, and what has that got to do with him trying to filch a sound machine? So maybe taking the car was just a stunt, but he really did try and run off with a novel sound machine!

As well as fronting his band Joey is an audio engineer. Unlike driving a car, which is all about seeing things around you – signs, cars pedestrians – being an audio engineer seems a natural job for someone who is blind. Its about recording, mixing and editing music, speech and sound effects. What matters most is that the person has a good ear. Having the right skills could easily lead to a job in the music industry, in TV and films, or even in the games industry. It’s also an important job. Getting the sound right is critical to the experience of a film or game. You don’t want to be struggling to hear mumbling actors, or the sound effects to drown out a key piece of information in a game.

Peter Francken in his studio. Image from Wikimedia Commons.

Mixing desks

Once upon a time Audio engineers used massive physical mixing desks. That was largely ok for a blind person as they could remember the positions of the controls as well as feel the buttons. As the digital age has marched on, mixing desks have been replaced by Digital Audio Workstations. They are computer programs and the trouble is that despite being about sound, they are based on vision.

When we learn about sound we are shown pictures of wavy lines: sound waves. Later, we might use an oscilloscope or music editing software, and see how, if we make a louder sound, the curves get taller on the screen: the amplitude. We get to hear the sound and see the sound wave at the same time. That’s this multimodal idea again, two ways of sensing the same thing.

But hang on, sound isn’t really a load of wavy lines curling out of our mouths, and shooting away from guitar strings. Sound is energy and atoms pushing up against each other. But we think of sound as a sound wave to help us understand it. That’s what a computer scientist calls abstraction: representing things in a simpler way. Sound waves are an abstraction, a simplified representation, of sound itself.

Sound waveform image by Gordon Johnson from Pixabay

The representation of sound as sound waves, as a waveform, helps us work with sound, and with Digital Audio Workstations it is now essential for audio engineers. The engineer works with lines, colors, blinks and particularly sound waves on a screen as they listen to the sound. They can see the peaks and troughs of the waves, helping them find the quiet, loud and distinctive moments of a piece of music, at a glance, for example. That’s great as it makes the job much easier…but only if you are fully sighted. It makes things impossible for someone with a visual impairment. You can’t see the sound waves on the editing screen. Touching a screen tells you nothing. Even though it’s ultimately about sounds, doing your job has been made as hard as driving a car. This is rather sad given computers have the potential to make many kinds of work much more accessible to all.

Feel the sound

The DePIC research team, a group of people from Goldsmiths, Queen Mary University of London and Bath Universities with a mission to solve problems that involve the senses, decided to fix it. They’ve created the first ever plug-in software for professional Digital Audio Workstations that makes peak level meters completely accessible. It uses ‘sonification’: it turns those visual signals in to sound! decided to fix the problems. They brought together Computer Scientists, Design experts, and Cognitive Scientists and most importantly of all audio engineers who have visual impairments. Working together over two years in workshops sharing their experiences and ideas, developing, testing and improving prototypes to figure out how a visually impaired engineer might ‘see’ soundwaves. They created the HapticWave, a device that enables a user to feel rather than see a sound wave.

The HapticWave

The HapticWave combines novel hardware and software to provide a new interface to the traditional Digital Audio Workstation. The hardware includes a long wooden box with a plastic slider. As you move the slider right and left you move forward and backwards through the music. On the slider there is a small brass button, called a fader. Tiny embossed stripes on the side of the slider let you know where the fader is relative to the middle and ends of the slider. It moves up and down in sync with the height of the sound wave. So in a quiet moment the fader returns to the centre of the slider. When the music is loud, the fader zooms to the top of the handle. As you slide forwards and backwards through the music the little button shoots up and down, up and down tracing the waveform. You feel its volume changing. Music with heavy banging beats has your brass button zooming up and down, so mind your fingers!

So back to the title of the article! Joey trialled the HapticWave at a research workshop and rather wanted to take one home, he loved it so much he jokingly tried distracting the researchers to get one. But he didn’t get away with it – maybe his getaway car just wasn’t fast enough!

3. An audio illusion, and an audiovisual one

This one-minute video illustrates an interesting audio illusion, demonstrating that our brains are ‘always using prior information to make sense of new information coming in’.

The McGurk Effect

You can read more about the McGurk effect on page 7 of issue 5 of the CS4FN magazine, called ‘The Perception Deception‘.

 

4. Previous Advent Calendar posts

CS4FN Advent – Day 1 – Woolly jumpers, knitting and coding (1 December 2021)

 

CS4FN Advent – Day 2 – Pairs: mittens, gloves, pair programming, magic tricks (2 December 2021)

 

CS4FN Advent – Day 3 – woolly hat: warming versus cooling (3 December 2021)

 

CS4FN Advent – Day 4 – Ice skate: detecting neutrinos at the South Pole, figure-skating motion capture, Frozen and a puzzle (4 December 2021)

 

CS4FN Advent – Day 5 – snowman: analog hydraulic computers (aka water computers), digital compression, and a puzzle (5 December 2021)

 

CS4FN Advent – Day 6 – patterned bauble: tracing patterns in computing – printed circuit boards, spotting links and a puzzle for tourists (6 December 2021)

 

CS4FN Advent – Day 7 – Computing for the birds: dawn chorus, birds as data carriers and a Google April Fool (plus a puzzle!) (7 December 2021)

 

CS4FN Advent – Day 8: gifts, and wrapping – Tim Berners-Lee, black boxes and another computing puzzle (8 December 2021)

 

CS4FN Advent – Day 9: gingerbread man – computing and ‘food’ (cookies, spam!), and a puzzle (9 December 2021)

 

CS4FN Advent – Day 10: Holly, Ivy and Alexa – chatbots and the useful skill of file management. Plus win at noughts and crosses – (10 December 2021)

 

CS4FN Advent – Day 11: the proof of the pudding… mathematical proof (11 December 2021)

 

CS4FN Advent – Day 12: Computer Memory – Molecules and Memristors – (12 December 2021)

 

CS4FN Advent – Day 13: snowflakes – six-sided symmetry, hexahexaflexagons and finite state machines in computing (13 December 2021)

 

CS4FN Advent – Day 14 – Why is your internet so slow + a festive kriss-kross puzzle (14 December 2021)

 

CS4FN Advent – Day 15 – a candle: optical fibre, optical illusions (15 December 2021)

 

CS4FN Advent – Day 16: candy cane or walking aid: designing for everyone, human computer interaction – this post

 

 

 

CS4FN Advent – Day 15 – a candle: optical fibre, optical illusions

After yesterday’s tinsel image inspiring a cable / broadband speeds themed post, today’s CS4FN Christmas Computing Advent Calendar picture of a candle has of course put me in mind of optical fibre, then that eminded me of optical illusions, so this is a light-hearted (sorry) look at those, shining a torch (or candle) into the CS4FN archives.

A candle

We’re now more than halfway through our advent calendar, having posted something every day for the last 15 days. Do we have enough material for the next 10 days? You betcha 🙂 CS4FN has been running for 16 years and we’ve produced 27 magazines for subscribing UK schools (they’re free, get your teacher to subscribe for next year’s magazine) and a whole load of other booklets and posters etc. We’ve been busy!

 

The optical pony express

by Paul Curzon, QMUL. This article originally appeared on the CS4FN website.

Read about the change in speeds in communications, from letters via pony express, to Morse via telegraph wires, then telephones via copper wires, and modern digital computing – and now at the speed of light via optical fibre.

The optical pony express

 

Illusions – The CS4FN Eye

by Paul Curzon, QMUL. This article originally appeared on our A Bit of CS4FN website.

Optical illusions tell us about how our brains work. They show that our brains follow rules that we cannot switch off.

12.ouchieye

Stare at the picture, moving your head a little as you do. The middle circle floats around as though it is not part of the rest of the eye. It isn’t moving of course. It was created by the Japanese artist Hajime Ouchi.

Your brain is doing some amazing tricks – turning the light hitting your eye into an understanding of the world around you. Knowing what is near and what is far, and whether there is movement, are things that all animals must do quickly (especially when a tiger is near rather than far!)

To work things out your brain makes some guesses. It has built in rules that spot patterns. One rule helps us guess if something is moving up and down. Another spots side to side movement.

The patterns in this picture trigger those rules, telling you there are two separate objects. The rules that allow your brain to make sense of the world quickly are telling you the wrong thing, and you cannot stop it happening!

Programs that allow computers to “see” like we do have to do more than record things like a camera. They need to make sense of what is there. They need to be able to tell objects apart. A driverless car needs to tell if that blotch of darkness is a pedestrian or just a shadow.

Machine learning is one way to do this. The computer learns rules about patterns in the data it records just as we do. If they do it well robots of the future may be fooled by the same optical illusions that we are.

 

Answer to yesterday’s puzzle

 

Previous Advent Calendar posts

CS4FN Advent – Day 1 – Woolly jumpers, knitting and coding (1 December 2021)

 

CS4FN Advent – Day 2 – Pairs: mittens, gloves, pair programming, magic tricks (2 December 2021)

 

CS4FN Advent – Day 3 – woolly hat: warming versus cooling (3 December 2021)

 

CS4FN Advent – Day 4 – Ice skate: detecting neutrinos at the South Pole, figure-skating motion capture, Frozen and a puzzle (4 December 2021)

 

CS4FN Advent – Day 5 – snowman: analog hydraulic computers (aka water computers), digital compression, and a puzzle (5 December 2021)

 

CS4FN Advent – Day 6 – patterned bauble: tracing patterns in computing – printed circuit boards, spotting links and a puzzle for tourists (6 December 2021)

 

CS4FN Advent – Day 7 – Computing for the birds: dawn chorus, birds as data carriers and a Google April Fool (plus a puzzle!) (7 December 2021)

 

CS4FN Advent – Day 8: gifts, and wrapping – Tim Berners-Lee, black boxes and another computing puzzle (8 December 2021)

 

CS4FN Advent – Day 9: gingerbread man – computing and ‘food’ (cookies, spam!), and a puzzle (9 December 2021)

 

CS4FN Advent – Day 10: Holly, Ivy and Alexa – chatbots and the useful skill of file management. Plus win at noughts and crosses – (10 December 2021)

 

CS4FN Advent – Day 11: the proof of the pudding… mathematical proof (11 December 2021)

 

CS4FN Advent – Day 12: Computer Memory – Molecules and Memristors – (12 December 2021)

 

CS4FN Advent – Day 13: snowflakes – six-sided symmetry, hexahexaflexagons and finite state machines in computing (13 December 2021)

 

CS4FN Advent – Day 14 – Why is your internet so slow + a festive kriss-kross puzzle (14 December 2021)

 

CS4FN Advent – Day 15 – a candle: optical fibre, optical illusions – this post

 

 

 

CS4FN Advent – Day 14 – Why is your internet so slow + a festive kriss-kross puzzle

Today’s CS4FN Christmas Computing Advent Calendar is showing a picture of shiny tinsel, which reminds me a bit of computer cables. At least, enough to theme this post around broadband speeds 🙂

A piece of shiny tinsel.

 

Did you know?

Only two letters were transmitted over the Internet before it crashed for the first time. The Internet was born on 20 October 1969 with the first transmission of data sent from a computer at the University of California to another one at Stanford, near San Francisco. Only two letters L and O were sent – the system crashed when the G of LOGIN was entered.

Why is your Internet so slow?

by Paul Curzon, QMUL. This article was originally published on the CS4FN website.

The Internet is now so much a part of life that, unless you are over 50, it’s hard to remember what the world was like without it. Sometimes we enjoy really fast Internet access, and yet at other times it’s frustratingly slow! So the question is why, and what does this have to do with posting a letter, or cars on a motorway?

The communication technology that powers the Internet is built of electronics. The building blocks are called routers, and these convert the light-streams of information that pass down the fibre-optic cables into streams of electrons, so that electronics can be used to switch and re-route the information inside the routers.

Enormously high capacities are achievable, which is necessary because the performance of your Internet connection is really important, especially if you enjoy online gaming or do a lot of video streaming. Anyone who plays online games would be familiar with the problem: opponents apparently popping out of nowhere, or stuttery character movement.

So the question is – why is communicating over a modern network like the Internet so prone to odd lapses of performance when traditional land-line telephone services were (and still are) so reliable? The answer is that traditional telephone networks send data as a constant stream of information, while over the Internet, data is transmitted as “packets”. Each packet is a large group of data bits stuck inside a sort of package, with a header attached giving the address of where the data is going. This is why it is like posting a letter: a packet is like a parcel of data sent via an electronic “postal service”.

But this still doesn’t really answer the question of why Internet performance can be so prone to slow down, sometimes seeming almost to stop completely. To see this we can use another analogy: the flow of packet data is also like the flow of cars on a motorway. When there is no congestion the cars flow freely and all reach their destination with little delay, so that good, consistent performance is enjoyed by the car’s users. But when there is overload and there are too many cars for the road’s capacity, then congestion results. Cars keep slowing down then speeding up, and journey times become horribly delayed and unpredictable. This is like having too many packets for the capacity in the network: congestion builds up, and bad delays – poor performance – are the result.

Typically, Internet performance is assessed using broadband speed tests, where lots of test data is sent out and received by the computer being tested and the average speed of sending data and of receiving it is measured. Unfortunately, speed tests don’t help anyone – not even an expert – understand what people will experience when using real applications like an online game. Electronic engineering researchers at Queen Mary, University of London have been studying these congestion effects in networks for a long time, mainly by using probability theory, which was originally developed in attempts to analyse games of chance and gambling. In the past ten years, they have been evaluating the impact of congestion on actual applications (like web browsing, gaming and Skype) and expressing this in terms of real human experience (rather than speed, or other technical metrics). This research has been so successful that one of the Professors at Queen Mary, Jonathan Pitts, co-founded a spinout company called Actual Experience Ltd so the research could make a real difference to industry and so ultimately to everyday users.

For businesses that rely heavily on IT, the human experience of corporate applications directly affects how efficiently staff can work. In the consumer Internet, human experience directly affects brand perception and customer loyalty. Actual Experience’s technology enables companies to manage their networks and servers from the perspective of human experience – it helps them fix the problems that their staff and customers notice, and invest their limited resources to get the greatest economic benefit.

So Internet gaming, posting letters, probability theory and cars stuck on motorways are all connected. But to make the connection you first need to study electronic engineering.

 

Today’s puzzle

Download a printable version

Festive kriss-kross puzzle.

The 11 words to fill in the squares in the puzzle above are: Advent, Bauble, Cards, Chimney, Decorations, Presents, Reindeer, Sleigh, Snowman, Stocking, Tree. Answer tomorrow.

From an earlier puzzle “You might wonder “What do these kriss-kross puzzles have to do with computing?” Well, you need to use a bit of logical thinking to fill one in and come up with a strategy. If there’s only one word of a particular length then it has to go in that space and can’t fit anywhere else. You’re then using pattern matching to decide which other words can fit in the spaces around it and which match the letters where they overlap. Younger children might just enjoy counting the letters and writing them out, or practising phonics or spelling.”

 

Previous Advent Calendar posts

CS4FN Advent – Day 1 – Woolly jumpers, knitting and coding (1 December 2021)

 

CS4FN Advent – Day 2 – Pairs: mittens, gloves, pair programming, magic tricks (2 December 2021)

 

CS4FN Advent – Day 3 – woolly hat: warming versus cooling (3 December 2021)

 

CS4FN Advent – Day 4 – Ice skate: detecting neutrinos at the South Pole, figure-skating motion capture, Frozen and a puzzle (4 December 2021)

 

CS4FN Advent – Day 5 – snowman: analog hydraulic computers (aka water computers), digital compression, and a puzzle (5 December 2021)

 

CS4FN Advent – Day 6 – patterned bauble: tracing patterns in computing – printed circuit boards, spotting links and a puzzle for tourists (6 December 2021)

 

CS4FN Advent – Day 7 – Computing for the birds: dawn chorus, birds as data carriers and a Google April Fool (plus a puzzle!) (7 December 2021)

 

CS4FN Advent – Day 8: gifts, and wrapping – Tim Berners-Lee, black boxes and another computing puzzle (8 December 2021)

 

CS4FN Advent – Day 9: gingerbread man – computing and ‘food’ (cookies, spam!), and a puzzle (9 December 2021)

 

CS4FN Advent – Day 10: Holly, Ivy and Alexa – chatbots and the useful skill of file management. Plus win at noughts and crosses – (10 December 2021)

 

CS4FN Advent – Day 11: the proof of the pudding… mathematical proof (11 December 2021)

 

CS4FN Advent – Day 12: Computer Memory – Molecules and Memristors – (12 December 2021)

 

 

CS4FN Advent – Day 13: snowflakes – six-sided symmetry, hexahexaflexagons and finite state machines in computing (13 December 2021)

 

CS4FN Advent – Day 14 – Why is your internet so slow + a festive kriss-kross puzzle (14 December 2021) – this post

 

 

 

CS4FN Advent – Day 13: snowflakes – make your own six-sided hexahexaflexagon with our templates

The picture for today’s door of the CS4FN Christmas Computing Advent Calendar is a snowflake and, inspired by its six-sides, this post is celebrating the similarly six-sided (and six-faced) hexahexaflexagon.

A snowflake in a blue circle

A hexahexaflexagon is a strip of paper cleverly folded to hide and then reveal six hexagonal faces within it. You pinch and flex them to reveal another face, as shown in the video below. It’s effectively a Möbius strip.

The name references a hexagonal shape which is flexed to show a new face (‘flexagon’) and the hexa-hexa bit just means each face has six sides and there are six faces.

An unfolded hexahexaflexagon design.

Flexagons were discovered in the late 1930s by a British maths student (Arthur Stone) who’d arrived at Princeton University with a binder / folder from home and discovered that American paper was too large to fit in. He cut off the excess strips and ‘doodled’ with them by folding them into different shapes, then involving his classmates in developing them.

There are lots of ways to make them but we’ve created some templates to help. You can print our hexahexaflexagons or make and decorate your own from scratch. Ours depict Father Christmas looking for the six presents he’s lost among the different faces but there’s a blank template if you’d like to design your own.

Of course there’s some computer science and maths behind these too – we have a free PDF booklet which you can download from the link below, called Computational Thinking: HexaHexaFlexagon Automata.

 

Print or make your own hexahexflexagon

 

 

The six faces of our ready-to-print hexahexaflexagon.

 

Previous Advent Calendar posts

CS4FN Advent – Day 1 – Woolly jumpers, knitting and coding (1 December 2021)

 

CS4FN Advent – Day 2 – Pairs: mittens, gloves, pair programming, magic tricks (2 December 2021)

 

CS4FN Advent – Day 3 – woolly hat: warming versus cooling (3 December 2021)

 

CS4FN Advent – Day 4 – Ice skate: detecting neutrinos at the South Pole, figure-skating motion capture, Frozen and a puzzle (4 December 2021)

 

CS4FN Advent – Day 5 – snowman: analog hydraulic computers (aka water computers), digital compression, and a puzzle (5 December 2021)

 

CS4FN Advent – Day 6 – patterned bauble: tracing patterns in computing – printed circuit boards, spotting links and a puzzle for tourists (6 December 2021)

 

CS4FN Advent – Day 7 – Computing for the birds: dawn chorus, birds as data carriers and a Google April Fool (plus a puzzle!) (7 December 2021)

 

CS4FN Advent – Day 8: gifts, and wrapping – Tim Berners-Lee, black boxes and another computing puzzle (8 December 2021)

 

CS4FN Advent – Day 9: gingerbread man – computing and ‘food’ (cookies, spam!), and a puzzle (9 December 2021)

 

CS4FN Advent – Day 10: Holly, Ivy and Alexa – chatbots and the useful skill of file management. Plus win at noughts and crosses – (10 December 2021)

 

CS4FN Advent – Day 11: the proof of the pudding… mathematical proof (11 December 2021)

 

CS4FN Advent – Day 12: Computer Memory – Molecules and Memristors – (12 December 2021)

 

 

CS4FN Advent – Day 13: snowflakes – six-sided symmetry, hexahexaflexagons and finite state machines in computing – this post

 

 

 

CS4FN Advent Calendar – bonus material: HexaFestiveFlexagons to make and colour in

Father Christmas has lost six of his presents inside this flexagon. The first two are easy to find but can you uncover the other four?

There’s a gift on side one, and another if you turn the hexahexaflexagon over. Another 4 to find inside the flexagon.

 

Print and make your own hexahexaflexagon and help Father Christmas find the missing gifts.

  1. Print (or draw) your flexagon
  2. Cut it out, then fold it following the instructions
  3. Find all of Father Christmas’ lost gifts by pinching and folding the flexagon to reveal the hidden faces
Folding a hexahexaflexagon – pinch and flex. Three sides are shown, there are another three inside the folds.

A hexahexaflexagon is a six sided shape (hexagon) which also has six faces in total (hexa-hexa) and which can flex and fold to show a new face (flexagon). They are fun to make and play with but can also be used to learn some computational thinking. To get to each face or side you may need to follow a variety of paths, you can’t always get to every face from every other face. The sides you can reach depend on the sides you currently have visible – it’s a ‘finite state machine’ and you can create a map to describe how you navigate around your hexahexaflexagon. See our page on Computational Thinking: HexaHexaFlexagon Automata and download our free booklet (PDF) to find out more. We definitely recommend this as an end-of-term classroom activity.

Computational Thinking: HexaHexaFlexagon Automata

Table of Contents
A. For people who want a ready-coloured hexahexaflexagon – print and go
B. For people who want to colour in their own hexahexaflexagon – print & colour in
C. For people who want to design their own hexahexaflexagon on a computer
D. For people who don’t have a printer or want to design a hexahexaflexagon from scratch
E. Useful videos

 

A. For people who want a ready-coloured hexahexaflexagon

• Print this PDF file: Father Christmas coloured hexahexaflexagon
• Use these instructions: CS4FN How to fold a hexahexaflexagon

 

 

 

B. For people who want to colour in their own hexahexaflexagon

• Print this PDF file: Father Christmas black and white hexahexaflexagon to colour (this contains a guide if you want each of the six faces to have its own colour)
• Use these instructions: CS4FN How to fold a hexahexaflexagon – black and white

 

 

 

C. For people who want to design their own hexahexaflexagon on a computer

• Print this PDF file: CS4FN blank hexahexaflexagon – design your own
• Use these folding instructions: CS4FN How to fold a hexahexaflexagon – black and white
• just the triangles – .svg / .png

It may be easier to make the flexagon first then colour it in, then it’s easier to see which triangle is on which face, but the printable does have instructions in if you want to make one that will ‘work’ once folded.

 

D. For people who don’t have a printer or who want to create one from scratch

• Read the instructions here: – CS4FN How to create a hexahexaflexagon from scratch
• Use these folding instructions: CS4FN How to fold a hexahexaflexagon – black and white
• Useful website for calculating the height needed for an equilateral triangle (if you want to create hexahexaflexagons on different sizes of paper) https://www.omnicalculator.com/math/equilateral-triangle

 

E. Useful videos

Above: CS4FN’s Paul Curzon demonstrates how to fold one (note that the direction of the first round of folding is different from the written instructions above, though it doesn’t matter if you go from A to B or B to A).

Above: Vi Hart has an excellent series of hexaflexagon and hexahexaflexagon videos including how they were discovered.

 

A picture showing all six faces of the hexahexaflexagon made for the CS4FN Christmas Computing Advent Calendar.

Part of our CS4FN Christmas Computing Advent Calendar.

CS4FN Christmas Computing Advent Calendar

 

CS4FN Advent – Day 12: Computer Memory – Molecules and Memristors

Computer memory molecular style, memristors, maths puzzle answer and a “20 questions” activity

Remember remember the 24th of December – as that’s the day to hang out your Christmas stocking! That’s the picture for today’s door on the CS4FN Christmas Computing Advent Calendar and I’ve made the somewhat stretched link between a stocking as a store for your presents and computer memory as a store for all your data.

A Christmas stocking. No presents though. Yet…

If your own memory needs a prod you can find a list of our previous posts at the end of this one.

Molecular memory

by Charlie Tizzrd, QMUL. This article was originally published on the CS4FN website.

What happens when computers need so much memory that they start to test the laws of physics? Charlie Tizzard investigates.

A new way to store data in individual molecules might put some life back into an old law of computing. Back in 1965, the founder of Intel, Gordon Moore, noticed that computer chips doubled their performance about every 18 months. Not only was he right in 1965, he kept on being right. Ten, twenty, even thirty years later, chip power still doubled every 18 months. This observation was so strong that it began to seem like a law of nature. It was named “Moore’s law” after Gordon Moore himself.

But some experts believe that Moore’s law is beginning to waver. As electronics continue to get smaller and smaller they are pushing the law to the limit. Electronics are now so small that even the laws of physics are even getting in the way. An esteemed physicist, Michio Kaku, said that “we already see a slowing down of Moore’s law. Computing power simply cannot maintain its rapid exponential rise using standard silicon technology.”
What to do?

Unless we move away from silicon-based storage in computing, we will run into some serious issues in the near future. Fortunately, scientists and engineers are experimenting with alternative ways of storing data. One way is to use molecules whose atoms can be shifted around within them. Storing data is all about making physical changes to something. That means you can put information in molecules by representing it as different atomic states. Best of all, those states can be changed and read by the same technology we have today: changes to the amount of electricity the molecules conduct.

Our only problem is that this idea works great inside a lab setting, but it can be difficult in the real world. First of all, molecular storage needs to be mass produced, but so far it’s specialised equipment built only in labs. Not only that, but up until now the molecules had to be kept at almost absolute zero (that’s -273°C) in order to work. But now an international team of researchers at MIT led by Jagadeesh Moodera have pioneered a new technique that allows the molecules to be kept at roughly the freezing point of water. In physics that’s practically room temperature.

Even more importantly, the molecules, which previously had to be sandwiched between two electrical conductors, only require one conductor in the MIT setup. That will make mass manufacturing a lot simpler and cheaper for companies. “This is only the tip of tip of the iceberg” says Moodera, so don’t be surprised if you are using chemicals for storing your photos in the future!

 

Do you remember the birth of the memristor?

by Paul Curzon, QMUL. This article was originally published on the CS4FN website.

A memristor – photo from Wikimedia Commons.

Electronics! It’s all been done long ago, hasn’t it? Resistors, transistors, capacitors, and inductors: all invented. See. Done it, filled in the worksheet, nothing else to discover…but did you miss the birth of the memristor?

In 2008 a new member of the electronics family was born. It had been discussed in theory as the missing link. It was mathematically possible, but never actually built till electronic engineers at Hewlett Packard used nanotechnology to bring it into existence.

Memristors are resistors with memory. Doh! Clever name! It can work as a data store, being either off or on, but it can store this information without any power too. This ability to store binary data (1s and 0s) with no drain on a battery, combined with its tiny, nanotechnology size means that memristors can store more data than any normal hard drive, and can be accessed as quickly as RAM – the kind of memory computers currently use. That means that in the future computers may be able to store more, start faster and be eco friendly too.

Building brains? That would be amazing enough but it turns out that the memistor has another trick up its nano-sleeve. Rather than working in digital mode, saving on/off (1,0) data like normal computer components, it can also hold values in between! The values it holds change every time the memristor receives an electrical signal, which is exactly what happens in the neurones of our brain as we learn. In the future networks of memristors could mimic the way our brains work, storing the things they learned from their electronic experiences. That would open up the possibility of a compact, low power way to build artificial intelligences.

Not bad for a humble little addition to the family of electronic components. See what you can miss is you don’t pay attention!

 

2. Today’s activity – the 20 questions game

The game 20 Questions, as the name suggests, involves trying to guess which famous person someone is thinking about by asking a maximum of 20 questions, all of which can be answered by YES or NO. The trick – of course – is to use good questions.

You’d be there all day if you kept asking them “Is it this person?”, “Is it that person?”. Those types of questions don’t chip away at the enormity of ~8 billion or so possibilities. Better questions might include “Are they alive?”, “Are they European?”. A yes or no answer to those questions tells you much more and helps narrow things down.

The game is a great way to learn about information theory and how the best questions are ones that split the options in half (roughly!). Most of the 8 billion people on Earth aren’t that famous, let’s assume it’s around 1 million people (because the maths is handy if we do!). If each of your questions divides a population of famous people in half each time and we start with one million people, how many questions do you need to ask before you get down to one person?

Or, to put it another way 2 (dividing in half) to the power of 20 (the 20 questions) or 220 gives 1,048,576 people (or items).

We developed an activity for teachers and students to do in the classroom (you can do it at home too) that uses the game to explore different search algorithms and improving how computers (and we) find information. It was number 4 in our 10 most popular downloads last year.

Use the activity to find out more about these computing concepts, while seeing how efficiently you can guess what someone else is thinking about.

  • computational thinking
  • linear search
  • binary search
  • divide and conquer
  • comparing algorithms

The 20-questions Activity

 

3. Answer to yesterday’s puzzle

 

 

4. Previous Advent Calendar posts

CS4FN Advent – Day 1 – Woolly jumpers, knitting and coding (1 December 2021)

 

CS4FN Advent – Day 2 – Pairs: mittens, gloves, pair programming, magic tricks (2 December 2021)

 

CS4FN Advent – Day 3 – woolly hat: warming versus cooling (3 December 2021)

 

CS4FN Advent – Day 4 – Ice skate: detecting neutrinos at the South Pole, figure-skating motion capture, Frozen and a puzzle (4 December 2021)

 

CS4FN Advent – Day 5 – snowman: analog hydraulic computers (aka water computers), digital compression, and a puzzle (5 December 2021)

 

CS4FN Advent – Day 6 – patterned bauble: tracing patterns in computing – printed circuit boards, spotting links and a puzzle for tourists (6 December 2021)

 

CS4FN Advent – Day 7 – Computing for the birds: dawn chorus, birds as data carriers and a Google April Fool (plus a puzzle!) (7 December 2021)

 

CS4FN Advent – Day 8: gifts, and wrapping – Tim Berners-Lee, black boxes and another computing puzzle (8 December 2021)

 

CS4FN Advent – Day 9: gingerbread man – computing and ‘food’ (cookies, spam!), and a puzzle (9 December 2021)

 

CS4FN Advent – Day 10: Holly, Ivy and Alexa – chatbots and the useful skill of file management. Plus win at noughts and crosses – (10 December 2021)

 

CS4FN Advent – Day 11: the proof of the pudding… mathematical proof (11 December 2021)

 

CS4FN Advent – Day 12: Computer Memory – Molecules and Memristors – (12 December 2021) – this post