Fundamentals of Data Representation

Question 1

Integer Numbers

Answer 1

Set of whole numbers, including positive and negative and zero

Z

Question 2

Rational Numbers

Answer 2

Set of integer numbers but can contain fractional parts

Q

Question 3

Irrational Number

Answer 3

Numbers which cannot be written as an exact fraction

No Symbol

Question 4

Real Numbers

Answer 4

All possible real world quantities

R

Question 5

Ordinal Numbers

Answer 5

Describe the numerical position of an object in relation to others

Question 6

Kibibyte in Bytes

Answer 6

2^10

Question 7

Mebibyte in Bytes

Answer 7

2^20

Question 8

Gibibyte in Bytes

Answer 8

2^30

Question 9

Tebibyte in Bytes

Answer 9

2^40

Question 10

Kilobyte in Bytes

Answer 10

10^3

Question 11

Megabyte in Bytes

Answer 11

10^6

Question 12

Gigabyte in Bytes

Answer 12

10^9

Question 13

Terabyte in Bytes

Answer 13

10^12

Question 14

Unsigned Binary Numbers

Answer 14

Only represent positive numbers

Question 15

Signed Binary Numbers

Answer 15

Allow for the representation of negative numbers

Question 16

Absolute Error with Equation

Answer 16

Actual amount by which a value is inaccurate

Difference between the values

Question 17

Relative Error with Equation

Answer 17

The measure of uncertainty between a given value compared to the actual value relative to the size of the given value

Relative Error = Absolute Error / Actual Value

Question 18

Underflow Error

Answer 18

When numbers are too small to be represented with bits available

Question 19

Overflow Error

Answer 19

When numbers are too large to be represented with bits available

Question 20

ASCII

Answer 20

Character set which can represent alphanumeric characters or symbols as a set of 8 bits (128 different characters)

Question 21

Unicode

Answer 21

Character set which includes more characters and symbols than ASCII as a set of 8 bits

Question 22

Parity Bit

Answer 22

Single bit which is added to a transmission of data in order to check for errors. Even and odd parity (Counts number of 1s)

Question 23

Majority Voting

Answer 23

Error checking technique where each bit of the data is transmitted multiple times where the most occurring value is taken, can check and correct the error

Question 24

Checksums

Answer 24

Error checking technique where a piece of data is added to the block of data in order to enable error detection

Question 25

Check Digit

Answer 25

Type of checksum where a single digit is added to the transmission

Question 26

Bitmap Graphics

Answer 26

Images are broken down into many pixels which are each assigned a binary value

Question 27

Resolution

Answer 27

The number of pixels in an image

Question 28

Colour Depth

Answer 28

Number of bits assigned to each pixel which can determine colours available

Question 29

Metadata

Answer 29

Data which is related to the image file itself, like width, height and colour depth

Question 30

Vector Graphics

Answer 30

Way of representing images using geometric shapes and objects

Question 31

Properties of Vector Graphics

Answer 31

Fill colour, fill style, line colour, dimensions...

Question 32

Vector Graphics Vs Bitmapped Graphics

Answer 32

Vector Graphics can be scaled without losing quality. Vector Graphics are better for simple images like logos but are not useful for photographs. Vector Graphics often use less storage space.

Question 33

Sampling Rate

Answer 33

Number of samples per second (Hz)

Question 34

Sample Resolution

Answer 34

Number of bits given to each sample

Question 35

Size of a Sound Sample (Equation)

Answer 35

Duration of sample (sec) x Sampling Rate (Hz) x Sampling Resolution

Question 36

The Nyquist Theorem

Answer 36

The sampling rate of an audio file must be at least twice the frequency of the sound

Question 37

Musical Instrument Digital Interface (MIDI) with examples

Answer 37

Used with electronic musical instruments which stores sound as a sequence of event messages (instructions) Duration of note Type of instrument Volume of note

Question 38

Advantages and Disadvantages of MIDI

Answer 38

Music can be manipulated easily without the loss of quality, note sounds can be altered and they are often smaller in size. But, they are not good at storing speech so can sound less realistic

Question 39

Lossy Compression

Answer 39

Type of data compression where some data is lost, like reducing the sample resolution or image resolution

Question 40

Lossless Compression

Answer 40

Type of data compression where no data is lost so can be reduced without decreasing the quality like run-length encoding and dictionary based methods

Question 41

Run Length Encoding (RLE)

Answer 41

Reduces the size of file by removing repeated information by replacing it with one occurrence of value and by how much it is repeated

Question 42

Encyption

Answer 42

The process of scrambling data so it cannot be understood if intercepted

Question 43

Caesar Cipher (2 types)

Answer 43

Type of Cipher where data is encrypted by replacing each character by the same key Shift Cipher Substitution Cipher

Question 44

Shift Cipher

Answer 44

Type of Caesar Cipher where all characters in the alphabet are shifted by the same amount (Key)

Question 45

Substitution Cipher

Answer 45

Type of Caesar Cipher where all characters are randomly replaced

Question 46

Disadvantages of Caesar Cipher

Answer 46

Can be cracked easily as frequency that characters occur could provide a clue. When one character is discovered in a shift cipher, all characters are found, but substitution are a little harder to crack

Question 47

Vernam Cipher

Answer 47

Type of cipher where each key is only used once for each character in the plaintext. Uses the binary value of character and key and applies a XOR operation in order to get the ciphertext.