Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Computer Science A level > Fundamentals of Data Representation > Flashcards

Fundamentals of Data Representation Flashcards

You may prefer our related Brainscape-certified flashcards:
Biology 101 flashcards
1
Q

What are natural numbers?

A

Natural numbers are a set of numbers that include all positive whole numbers and zero. They are used for counting items.
The symbol for natural numbers is ℕ.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
1
Q

What are integer numbers?

A

Integer numbers are a set of whole numbers, including positive numbers, negative numbers, and zero.
The symbol for integer numbers is ℤ.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are rational numbers?

A

Rational numbers can have a fractional part and can be written as a fraction of one number over another.
The symbol for rational numbers is ℚ.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are irrational numbers?

A

Irrational numbers cannot be written exactly as a fraction and include numbers like π, √2, and e.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are real numbers?

A

Real numbers include all possible real-world quantities and encompass irrational numbers, rational numbers, integers, and natural numbers.
The symbol for real numbers is ℝ.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are ordinal numbers used for?

A

Ordinal numbers are used to describe the numerical positions of objects in relation to others, such as 1st, 2nd, or 3rd.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is a bit?

A

A bit is the fundamental unit of information that can take two values, 1 and 0.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is a byte?

A

A byte is a collection of 8 bits.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is a nybble?

A

A nybble is half a byte, consisting of 4 bits.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How is a bit denoted?

A

A bit is denoted with a lowercase “b”.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How is a byte denoted?

A

A byte is denoted with an uppercase “B”.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

How many bits are in 2 bytes?

A

There are 16 bits in 2 bytes.
2 x 8 bits

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How many bits are in 20 bytes?

A

There are 160 bits in 20 bytes.
20 x 8 bits

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How many different values can be represented with a specified number of bits?

A

There are 2^n different values that can be represented with n bits

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How many different values can be represented with 8 bits?

A

With 8 bits (1 byte), there are 256 different values that can be represented (2^8 = 256).

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the value of 1 kilobyte (KB)?

A

1 kilobyte (KB) = 1000 bytes.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

How do you calculate absolute error?

A

Absolute error is calculated by finding the difference between the given value and the actual value.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

How do you calculate relative error?

A

Relative error is calculated by dividing the absolute error by the actual value.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is the advantage of floating point representation over fixed point representation?

A

Floating point representation allows for a greater range of numbers with a given number of bits by utilizing an exponent, which can be positive or negative.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is normalization in floating point numbers?

A

Normalization in floating point numbers ensures that the number starts with 01 (for positive numbers) or 10 (for negative numbers) in order to provide the maximum level of precision.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is underflow?

A

Underflow occurs when very small numbers are to be represented, but there are not enough bits available to accurately represent them.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is a character code?

A

A character code is a decimal digit used to represent a character in an information coding system.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

How many bits are used in ASCII to represent different characters?

A

ASCII uses 7 bits to represent 128 (= 2^7) different characters

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What are parity bits used for?

A

Parity bits are used for error checking in transmitted data.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

How does majority voting work?

A

In majority voting, each bit of the data is transmitted multiple times, and the most commonly occurring value is considered correct.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What is a checksum?

A

A checksum is a value calculated based on the data being transmitted, which is added to the transmitted data for error detection.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What is a check digit?

A

A check digit is a single digit added to the transmitted data as a form of checksum to detect errors.

27
Q

What is the efficiency of parity bit, majority voting, checksum, and check digit for error detection and correction?

A
  • Parity bit: Can detect errors in transmission but can only correct errors if an odd number of bits are changed. It is very efficient.
  • Majority voting: Can detect and correct errors as long as the majority of bits remain unchanged. It is inefficient due to increased data volume.
  • Checksum: Can detect errors but cannot correct them. It is mostly efficient, depending on the complexity of the algorithm used.
  • Check digit: Can detect errors but cannot correct them. It is efficient as the algorithms used for calculating check digits are limited in complexity.
28
Q

What is an advantage of ASCII over Unicode?

A

ASCII requires fewer bits (7 bits) compared to Unicode, which allows for more efficient storage and transmission of data.

29
Q

What is an advantage of Unicode over ASCII?

A

Unicode can represent a much wider range of characters, including various languages, symbols, and emojis.

30
Q

What is an advantage of majority voting over parity voting?

A

Majority voting can not only detect errors but also correct them, whereas parity voting can only detect errors.

31
Q

What is a disadvantage of parity voting?

A

Parity voting can only detect errors if the number of changed bits is odd; it cannot detect errors if an even number of bits are changed.

32
Q

How does majority voting handle multiple bit errors?

A

Majority voting has the capability to correct errors even when the values of multiple bits have changed, providing robust error correction.

33
Q

How does parity voting handle multiple bit errors?

A

Parity voting fails to detect errors if an even number of bits have changed, making it less reliable than majority voting in such cases.

34
Q

What is the difference between analogue and digital data?

A

Analogue data is continuous and can take any value, while digital data is discrete and can only take specific values.

35
Q

How does an analogue signal differ from a digital signal?

A

An analogue signal can take any value and can change as frequently as required, while a digital signal must take one of a specified range of values and can only change at specified intervals.

36
Q

What devices are used for digital-to-analogue conversion and analogue-to-digital conversion?

A

A digital-to-analogue converter (DAC) is used for digital-to-analogue conversion, while an analogue-to-digital converter (ADC) is used for analogue-to-digital conversion.

37
Q

What is the process of sampling in analogue-to-digital conversion?

A

Sampling involves taking regular readings of an analogue signal at specific intervals to record its values digitally.

38
Q

How is an image represented in bitmap graphics?

A

In bitmap graphics, an image is broken down into pixels, and each pixel is assigned a binary value.

39
Q

What determines the resolution of an image?

A

Resolution can be expressed as the number of dots per square inch (dpi) or the number of pixels in the image.

40
Q

What is colour depth in bitmap graphics?

A

Colour depth refers to the number of bits assigned to each pixel in an image, determining the number of colours that can be represented.

41
Q

How do you calculate the storage required for a bitmap image?

A

Multiply the number of pixels (width × height) by the bit depth to calculate the storage required.

42
Q

What additional information can be included in a bitmap image file?

A

Bitmap image files may contain metadata, such as the image’s width, height, date created, and colour depth, in addition to the pixel data.

43
Q

How are images represented in vector graphics?

A

Vector graphics represent images using geometric objects and shapes, storing the properties of each shape in a list.

44
Q

What is the advantage of vector graphics when it comes to scaling images?

A

Vector graphics can be scaled without losing quality, unlike bitmapped graphics, which may result in blurriness or pixelation when enlarged.

45
Q

Which type of graphics is more suitable for storing photographs?

A

Bitmapped graphics are used for storing photographs.

46
Q

How does a computer represent sound digitally?

A

Computers represent sound as a sequence of discrete samples, each taking a digital value.

47
Q

What is the sampling rate in sound representation?

A

The sampling rate is the number of samples per second and is measured in Hertz.

48
Q

What does the sample resolution in sound representation refer to?

A

The sample resolution is the number of bits allocated to each sample and affects audio quality and file size.

49
Q

How can the size of a sound sample be calculated?

A

Multiply the duration of the sample in seconds by the sampling rate in Hertz and the sample resolution in bits.
(Sound Sample (fbs) = Sampling Rate (f) x Sample in bits (b) x duration of sample (s)

50
Q

What is the Nyquist theorem in sound representation?

A

The Nyquist theorem states that the sampling rate must be at least twice the frequency of the sound to accurately represent it.

51
Q

What is MIDI used for?

A

MIDI (Musical Instrument Digital Interface) is used with electronic musical instruments connected to computers to store sound as a series of event messages.

52
Q

What are the advantages of using MIDI over sampled recordings in music representation?

A

Advantages of MIDI include easy manipulation of music without quality loss, changing instruments, transposing notes, and altering note duration. MIDI files are also smaller in size and lossless.

53
Q

Why are files compressed?

A

Files are compressed to reduce their size, enabling faster transfer between storage devices or over the internet.

54
Q

What are the two categories of compression?

A

The two categories of compression are lossy compression and lossless compression.

55
Q

What is the difference between lossy and lossless compression?

A

Lossy compression results in some information loss, while lossless compression reduces file size without decreasing quality.

56
Q

What are two methods of lossless compression?

A

Two methods of lossless compression are run length encoding (RLE) and dictionary-based methods.

57
Q

Explain run length encoding (RLE).

A

RLE reduces file size by removing repeated information and replacing it with one occurrence of the repeated information followed by the number of times it is to be repeated.

58
Q

What are dictionary-based methods in compression?

A

In dictionary-based methods, a dictionary containing repeated data is appended to the file to reduce its size.

59
Q

Which type of data is most suitable for compression using run length encoding and dictionary-based methods?

A

Files that contain a lot of repeated data are most suitable for compression using these methods.

60
Q

What is encryption?

A

Encryption is the process of scrambling data to keep it secure during transmission, making it unreadable if intercepted.

61
Q

What is plaintext and ciphertext?

A

Unencrypted information is referred to as plaintext, while encrypted information is called ciphertext.

62
Q

What are Caesar ciphers?

A

Caesar ciphers encrypt information by replacing characters, either by shifting the alphabet or using substitution.

63
Q

What is the Vernam cipher?

A

The Vernam cipher is a one-time pad cipher that requires a random key at least as long as the plaintext, encrypting by applying a logical XOR operation.

64
Q

Is the Vernam cipher considered secure?

A

Yes, the Vernam cipher is considered completely secure and is the only cipher mathematically proven to be so.

65
Q

What is computational security in ciphers?

A

Ciphers other than the Vernam cipher are theoretically crackable but not within a reasonable timeframe given current computing power, relying on computational security.

Computer Science A level (9 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions