Year 10 Error Detection

Key Terms

Data Integrity - The accuracy, completeness and consistency of data.

Validation - method used to ensure entered data is reasonable and meets certain criteria.

Verification - method used to ensure data is correct by using double entry or visual checks.

Check Digit - additional digit appended to a number to check if entered data is error free.

Modulo-11 - method used to calculate a check digit based on modulus division by 11.

Checksum - verification method used to check if data transferred has been altered or corrupted, calculated from the block of data to be sent.

Parity Check - method used to check if data has been transferred correctly that uses even or odd parity.

Parity bit - an extra bit found at the end of a byte that is set to 1 if the parity of the byte needs to change to agree with sender/receiver parity protocol.

Odd parity - binary number with an odd number of 1-bits.

Even parity - binary number with an even number of 1-bits.

Parity block - horizontal and vertical parity check on a block of data being transferred.

LEARN THE FUNDAMENTALS OF Error Detection

Task 1

Error checking in ASCII

Click the image to complete!

Now you have learnt about ASCII you can apply your knowledge and understand how the computer checks for errors.

Task 2

Parity Check

Click the image to complete!

Using binary cards to conduct a magic trick.

Task 3

Error checking Colour Puzzle

Click the image to complete!

Show that no more than four colours are required to colour the regions of the map or pattern so no two adjacent regions have the same colour.

Check Digits

How many people do you know check their dockets at the supermarket or in a shop to be sure that what they purchased matches the docket?

You can calculate what the last digit will be on a 12 or 13 digit product code (the number on a barcode).

https://www.csfieldguide.org.nz/en/chapters/coding-error-control/check-digits-on-barcodes/

Task 4

Barcode Check Digit

Click the image to complete!

ERROR DETECTION ASSESSMENT

You may use the Checksum calculator on the CS Field Guide to help you

FURTHER RESOURCES

More Check Digit Scenarios

Click on the image to go to the CS Field Guide Error Control page

Scroll to the bottom where you will find 'Project with check sums'

There are 5 more options you can learn how the check sum works. You can then use the generator to generate some random numbers for you to practice working it out.

ISBN-10
Credit Card
UIC wagon numbers (Trains)
NZ Tax ID Number
Machine Readable Passport (Passport Dates)

We covered GTIN-13 / ISBN-13 above.

Click on the image to Write up what you found out

QR Codes

A QR code consists of black squares arranged in a square grid on a white background, which can be read by an imaging device such as a camera, and processed using Reed–Solomon error correction until the image can be appropriately interpreted.

https://www.csfieldguide.org.nz/en/chapters/coding-error-control/qr-codes/

Parity Game

See what level you can get to.

How Space Weather Can Influence Elections on Earth

Back in 2003, Belgium was holding a national election. One of their first where the votes would be cast and counted on computers. Thousands of hours of preparation went into making it unhackable. And when the day of the vote came, everything seemed to have gone well. That was, until a cosmic chain of events caused a single bit to flip and called the outcome into question. -Radiolab

https://www.vice.com/en/article/9agbxd/space-weather-cosmic-rays-voting-aaas

https://www.wnycstudios.org/podcasts/radiolab/articles/bit-flip

Computational thinking for digital technologies

At the end of this topic students will have had the opportunity to cover;

understand that there can be more than one algorithm for the same problem PO3
understand that digital devices store data using just two states represented by binary digits PO3
recognise that computers need to search and sort large amounts of data PO4
understand how computers store more complex types of data using binary digits PO5

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