Fundamentals of data representation definitions

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Across
  1. 2. A substitution cipher where each letter of plaintext is substituted for another that is a fixed number of letters ahead in the alphabet, which becomes the ciphertext.
  2. 4. A sufficiently accurate digital waveform of an analogue signal would require a sampling rate of at least twice the highest frequency that appears in the original analogue signal.
  3. 5. The total number of pixels in an image expressed in terms of its dimensions: (width in pixels) x (height in pixels).
  4. 6. The process of converting analogue sound waves to a digital waveform, by storing a finite number of readings in binary.
  5. 7. A compression algorithm that retains all the data in the file by only storing the instructions needed to reconstruct the original file. No data is lost.
  6. 9. Number which cannot be expressed as a ratio of two integers, and hence do not lie within the set of rational numbers. {π, √2, e, … }
  7. 12. A transmission of a set of analogue data structures, that varies with time, between computational processes.
  8. 13. A compression algorithm that removes non-essential data from a file leading to a noticeable decrease in accuracy of the data. Data lost is non-recoverable.
  9. 16. A form used to represent numbers with a fractional part in any number system. The radix point is free to move due to the presence of an adjustable exponent.
  10. 17. An integrated circuit capable of converting continuous analogue data to discrete digital data for a computer.
  11. 18. The percentage difference between the exact correct value and rounded value.
  12. 20. The set of numbers that can represent real world quantities and have an imaginary part of 0. Rational and irrational numbers are all members of the real numbers. ℝ ={π, 1.5, -7, 3/4, 2, 100000000, -11.3432, … }
  13. 22. A number system that only uses 10 characters (0 to 9) to represent numbers (a base 10 system).
  14. 24. A cipher that uses a one-time pad (a secret random key) to convert each character to cipher text by modularly adding it with the corresponding character of the key. This is impossible to decrypt without a key.
  15. 25. Data whose values can vary continuously and take on any value between two extremes.
  16. 26. A type of lossless compression where text is searched for entries that match the entries in a dictionary. Entries are substituted by a unique code which can then be translated.
  17. 30. A number system that only uses ones and zeros to represent numbers (a base 2 system).
  18. 32. A prefix to a unit representing a power of 10. (kilo=10^3, mega=10^6, giga=10^9, tera=10^12)
  19. 34. Data related to the image file data itself. This includes image properties such as width, height and colour depth.
  20. 36. A form used to represent numbers with a fractional part in any number system. Digits after the fixed point are multiplied by the base raised to a negative power.
  21. 37. A component of floating point form that stores the number of positions to move the decimal point.
  22. 38. The process of ensuring a floating point number is represented as efficiently as possible by adjusting the position of the radix point and exponent.
  23. 40. the misrepresentation of a numeric value because it is too small to be represented with the allocated number of digits in the mantissa and exponent.
  24. 46. A character set that is a superset of ASCII. It is used to represent alphanumeric characters or symbols as an integer code point which is equal to the character’s ASCII code.
  25. 47. A binary number system that can only represent positive numbers.
  26. 51. A method of checking binary codes for errors during data transmission by counting the number of ones and zeros present.
  27. 52. The number of bits used to represent a single sample.
  28. 53. the misrepresentation of a numeric value because it is too large to be represented with the allocated number of digits in the mantissa and exponent.
  29. 54. The set of numbers with no fractional part. The natural numbers are a subset of the integers. ℤ = { … , -3, -2, -1, 0, 1, 2, 3, … }
  30. 56. A unique binary representation of a character. Not to be confused with the binary representation of a decimal digit, which is its numerical value in the binary system.
  31. 58. The amount of storage required for a bitmapped image is at least its (image size) × (colour depth).
  32. 59. An image composed of an array of pixels each with an allocated number of bits, arranged to form an image. Also known as raster graphics.
  33. 60. A method of checking binary codes for errors during data transmission by sending each bit multiple times, in a set. The receiver takes the value with most occurrences in a set as the value for that bit.
Down
  1. 1. An integrated circuit capable of converting discrete digital data from a computer to continuous analogue data.
  2. 3. The number of samples taken per second.
  3. 8. The difference between the exact correct value and rounded value.
  4. 10. A measure of the total number of pixels in an image, typically expressed in terms of the number of dots/pixels per inch.
  5. 11. A coding scheme used in signed binary to represent negative as well as positive numbers. A negative number is represented by flipping all its digits and adding 1 to the most significant bit.
  6. 14. A character set used to represent alphanumeric characters or symbols as a set of 8 bits.
  7. 15. A method of checking codes for errors during data transmission by calculating the sum of transmitted digits.
  8. 19. A binary number system that can represent both positive and negative numbers.
  9. 21. An image composed from mathematical coordinates and functions (lines and curves).
  10. 23. The process of converting the original data (plaintext) into a form which cannot be understood by unauthorised users (ciphertext) using an encryption algorithm (cipher).
  11. 27. A method of checking codes for errors during data transmission by adding an extra digit to the end (usually calculated/processed from digits in the code itself) that checks whether the data is accurate.
  12. 28. The number of unique digits used by a particular number system to represent numbers.
  13. 29. Natural numbers used to describe numerical position or order of objects.
  14. 31. A transmission of a set of digital data structures, that varies with time, between computational processes.
  15. 33. A type of lossless compression where repeated occurrences of the same data (like several pixels of the same colour in an image) are stored as single data values with their counts.
  16. 35. Errors inherently introduced to any calculations with fixed or floating point numbers since they cannot store numbers with infinite precisions.
  17. 39. Binary data transmitted between the MIDI device and computer processor that carries properties controlling when and how sounds are produced.
  18. 41. The set of numbers that can be expressed as the ratio of two integers. The integers are a subset of the rational numbers since all integers can be expressed as a ratio with 1. ℚ = {0, 1/2, 0.75, 0.111111 … , 300.5, -42, … }
  19. 42. Data whose values can vary discretely and can only take on one of a finite number of values between two extremes.
  20. 43. A number system that only uses 16 characters (0 to 9 and A to F) to represent numbers (a base 16 system).
  21. 44. Musical Instrument Digital Interface is a protocol for ADC audio transmission to a digital interface used for the majority of electronic musical instruments and computers.
  22. 45. The set of positive integers and 0. They can be used as cardinal (counting) or ordinal (ordering) numbers. ℕ = {0, 1, 2, 3, … }
  23. 48. A prefix to a unit representing a power of 2. (kibi=2^10, mebi=2^20, gibi=2^30, tebi=2^40)
  24. 49. A component of floating point form that stores the non-zero significant digits of a number.
  25. 50. A group of 8 bits.
  26. 55. A measure of the amount of colour used in an image, expressed in terms of the number of bits per pixel.
  27. 57. A binary digit used by computers as the fundamental unit of information.