ICT AS revision - Topic 1

Data, information, knowledge and processing.

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Data

Definition:

Data is raw facts and figures before they have been processed

'Raw facts and figures' means that the figures that you see have no actual meaning until they have been processed. For example

BAT46&&7 and 478GH89

Key facts -

  • data can be alphanumeric characters, sound or graphics
  • data is raw facts before it has been processed
  • data has no meaning


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Information

Information is made by taking data and processing it. This means performing some action in the data, this could be searching, sorting or editing the information. The act of processing gives the data meaning.

This formula shows how data becomes information:

Information = Data + [Structure] + [Context] +[Meaning]

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Knowledge

Knowledge is the application if that information to a situation - putting the information to use in other words.

Example

Data: 46, 54

Information: scores for team 1 and team 2 in a pub quiz

Knowledge: team 2 won the quiz

Knowledge can change, and as we add more information the knowledge is then revised and there may be a different outcome.

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Data Types

We already know that any data is made up of alphanumerics, and these can be split into different data types.

A data type is a sort of alphanumeric character that can be allocated. There are five different data types, these are:

  • Boolean
  • Real
  • Integer
  • Text/String
  • Date/Time


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Data Type meanings

Boolean: The boolean is a data type that can contain one of only two values - e.g. true or false, Yes or No.

Real: This data type contains numbers that will have decimal places, for example 45.298 and 218.99. It is used to hold numbers where precision is important.

Integer: This data type contains whole numbers with NO decimal places for example 16, 47, 99. This is used when there is no vital need for accuracy.

Text/String: This is any alpha numeric character and can contain symbols, text and number. the text is used to convey information

Date/Time: This contains numbers and letters, which depending on the format used displays the date and the time to different degree of accuracy.

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Representation - Text

Advantages:

  • clear to understand
  • lots of detail

Disadvantages:

  • Need to be able to read
  • Need to understand the language
  • Can be confusing
  • Lots of text cannot be read quickly - road signs
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Graphics

Advantages:

  • Multilingual - do not need language to understand
  • Can match what you see - physical shapes

Disadvantages:

  • Can be confusing if you do not know what the symbol means, and not everyone knows road signs
  • Some symbols do not mean the same things in different countries
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Sound

Advantages::

  • No fixed position
  • No line of sight required
  • Good for the visually impaired

Disadvantages:

  • No good in large areas - distortion of sound
  • Usually language based
  • May not know the sound - different alarms have different sounds
  • Need to be able to hear
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Moving Images

Advantages:

  • Lots of information conveyed
  • Not language dependant
  • Can exemplify text

Disadvantages:

  • Linear - If you do not see the beginning then you will not know what it is showing
  • Problems if sound is with them
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LED

Advantages:

  • Can allow data to be kept secure
  • Can be used in noisy places
  • Similar to graphics

Disadvantages:

  • Need to be able to see the lights
  • combinations of lights may need to be known to be understood
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Normalisation

1NF - every data value in a field is atomic and each record does not contain repeating data

2NF - The table is in 1NF and all its non key attributes are dependant on the entire primary key.

3NF - It is in 2NF and there is no function dependancy between non-key attributes.

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Normaisation - Advantages and Disadvantages

Advantages

  • No redundent data
  • Easier to maintain
  • Effiecient structure
  • The database is more flexible
  • More relible
  • Consistant

Disadvantages

  • Reduced database performance
  • A computer need to use more processes to search through the database
  • you cannot store historical data
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Mail Merge

Mail merging allows the user to create and send a personalised version of the same document to many people and organisations. This is created using merge fields and an example of this would be Dear <title> <lastname>.

Advantages

  • Documents can be created quickly
  • only one copy of the document need to be proofread
  • The data source can be used in many mail merges
  • Can be saved and reused/edited
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Bitmap Images

Bitmap Images -

A bitmap graphic is made up of pixels, and each pixel is represented by one bit which is either switched on or off.

  • When resized there is a lowering of image quality. The image will become blurry
  • Each pixel has to be saved individually - file sizes may be large.
  • More consistent with general computing environment.
  • Popular - complex high detailed images.
  • Can be compressed.
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Vector Images

Rather than being stored as data relating to a grid of pixels, this type of gra0phic is stored as geometric-based data. It contains mathematical data that defines the key properties of every element in the graphic.

  • Can be resized or re-scaled with no loss of definition
  • Small in relation to file size.
  • Every componement is described by its features
  • Can be grouped.
  • Cannot be compressed
  • High processing power required
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The Data Protection Act (1998)

Set up to protect individuals from organisations.

Main rights:

  • Right to subject access
  • Right to prevent processing likely to cause damages or dstress
  • Right to prevent processing for the purposes of direct marketing
  • Rights in relation to automated decision making
  • Right to compensation if damage and distress is suffered by the act ebing contravened
  • Right to rectify, block or ease incorrect data
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RIPA

Benefits -

  • Monitor what there employees are doing
  • Ensures that all there facillities arebeing used legitimatly
  • Ensures that company secrets are not being revealed.
  • 

Problems -

  • Breach of Trust
  • Some people may say that they have nothing to hide
  • Concerns about who is actually monitoring the communications
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Peer-to-Peer Networks

A computer network where all the computers connected to it are of equal status. For example a home network

Advantages -

  • Do not need to purchase an expensive server
  • Indiviually manage your own computer
  • Set up using wizards - Easy
  • Netwrok remains robust if it fails

Disadvantages -

  • Each computer isfurfilling more that one role therefore it takes up more CPU.
  • Data can be stored on any computer
  • Security is not ensured on all computer from the server.
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Client - Server

Controlled by a powerful centeral computer.

Advantages -

  • Back-up, security and anti-virus is centeralised.
  • Shared data is organised
  • Network processing is done centerally

Disadvantages -

  • Cost Money
  • Network manager required
  • Relience on the central server.
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Referencial Intergrity

Prevents and caps in teh information when it has be normalised.

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