Data, information, knowledge and processing

Data, information, knowledge and processing

1. Data, information and knowledge

   • Data: raw number, letters, symbols, sounds or images
   • Information: data with context and meaning
   • Knowledge: information to which human experience has been applied

2. Sources of data

   • Static data: data that does not normally change
   • Dynamic data: data that changes automatically without user intervention
   • Direct data source: data that is collected for the purpose for which it will be used
   • Indirect data source: data that was collected for a different purpose (secondary source)

3. Quantity of information

   • Accuracy: information that is inaccurate is clearly not good enough. Data must be accurate in order for it to be considered of good quality
   • Relevance: information must be relevant to it's purpose​.
   • Age: information must be up to date inorder to be useful
   • Level of detail: there needs to be right amount of information for it to be good quality
   • completeness: all information that is required must be provided inorder for it to be of good quality

4. Checking the accuracy of data

   • Verification: ensures data entered into the system matches the original source
     • Visual checking: a method of verification can be for the user to visually check that the data entered matches the original source
     • Double data entry: another method of verification is to input dta into the computer system twice
   • Validation: the process of checking dta matches acceptable rules
     • Presence check: is used to ensure that data is entered
     • Range check: ensures that data is within a defined range
     • Type check: ensures that data must be of a defined data type
     • Length check: ensures data is of a defined length or within a range of legths
     • Format check: ensures data matches a defined format
     • Lookup check: tests to see if data exists in a list
     • Consistency check: compares data in one field with data in another field that already exists within a record to see whether both are consistenet with each other
     • Check digit: is a number (or letter) that is added to the end of identification number being input
   • Proof reading: checking information manually

5. Coding, encoding and encrypting data

   • Encryption: scrambling data so it can be understood without a decryption key to make it understandable if interceptted
     • Symmetric encryption: this is the oldest method of enryption. it requires both the sender and recipient to processes the secret encryption and decryption key
     • Asymmetric encryption: is also known as public key cryptography, it also overcomes the problems of symmetric encryption keys being intercepted by using a pair of keys (public and private key0
     • Hard disk: disk encryption will encryption will encrypt eery single bit of data stored on a disk, this is different to encrypting single files
     • Email: email encryption uses asymmetric encryption, this means that emails must have a private key
     • Caeser cipher: a cipher is a secret way of writing, caeser cipher is sometimes known as a shift cipher because it selects replacement letters by shifting along the alphabet
     • HTTPS: hypertext transfer protocol secure
     • TLS: transport layer security
     • SSL: secure sockets layers
   • Encoding: storing data in a specific format
     • Images: encoding is also used to store images ata the most basic level, images are encoded as bitmaps
     • Text: is encoded as a binary number
     • Sound: when sound is encoded the sample rate, bit depth and bit rate are stored
     • Video: when video is encoded it needs to store images as well as sound
   • Coding: representing data by assigning a code to it for identification