Data Representation

Question 1

Data

Answer 1

Raw numbers, symbols, images sounds etc.
Unprocessed
Meaningless

Question 2

Information

Answer 2

Interpreted and processed data

With context and meaning

Question 3

Knowledge

Answer 3

Information which human experience has been applied

Question 4

Knowledge Base

Answer 4

A collection of knowledge

Question 5

Static Data

Answer 5

Data that does not normally change

e.g. Birthday of someone

Question 6

Dynamic Data

Answer 6

Data that changes automatically without user intervention

e.g. Live score, stock price

Question 7

Static information source

Answer 7

e.g. Published book, CD
Information does not change on a regular basis
Information may go out of date
Information can be viewed offline since no update
More likely to be accurate since it is available for a long period of time, thus more chance to check

Question 8

Dynamic information source

Answer 8

e.g. Websites
Information is updated automatically 
More likely to be up to date
Network connection is required to update
Data may have been produced very quickly and may contains errors

Question 9

Direct Data Source

Answer 9

Data collected to serve that particular purpose

e.g. Census to collect statistical data of residents

Question 10

Indirect Data source

Answer 10

Data was collected for another purpose, usually the one who consumes the data is different from who collected them
e.g. Census is done by Government, but a company can use those data for different purpose

Question 11

Direct Data Source (vs)

Answer 11

Data is relevant since it is collected for that purpose
Original source is known, can be trust
Take long time to gather
Data is likely up to date
Data can be collected and presented in the required format

Question 12

Indirect Data Source (vs)

Answer 12

Some required data may not exist
Original source may not known => not reliable
Data is immediately available (someone collected already)
Data may not be up to date
Data may existed in different format, need time to process

Question 13

Attributes of (quality) information

Answer 13

Accuracy
Relevance: How related the data to its purpose
Age: Data must stay up to date
Level of Detail: Right amount of detail for the data. Too little then may not be enough information to use, too detail maybe hard to extract the information needed
Completeness: Is all information required is provided

Question 14

Coding

Answer 14

Representing data by assigning a code to it for classification or identification

Question 15

Encoding

Answer 15

Storing data in a specific format

Question 16

Encryption

Answer 16

Scrambling data to make it undreadable if intercepted

Encrypt with encryption algorithm and key

Question 17

Symmetric Key encryption

Answer 17

Encrypt and Decrypt use the same key

Question 18

Asymmetric key encryption

Answer 18

Sometimes refer as private key encryption
Encrypt with public key, decrypt with private key
Public key can encrypt but cannot decrypt
Public key is generated by private key

Question 19

SSL/TLS

Answer 19

Secure protocols used in HTTPS

Establish secure, trusted and encrypted communication between browser and web server

Question 20

Codec

Answer 20

Code and Decode

A particular method to encode multimedia data

Question 21

Validation

Answer 21

Automatically checking data according to predefined rules

• Presence
• Format
• Lookup
• Range
• Type
• Length
• Consistency
• Check Digit

Question 22

Verification

Answer 22

Ensure data entered matches the original source
- Double entry
- Visual Check
Often done manually

Question 23

Proofreading

Answer 23

Checking accuracy of data manually

Question 24

Audio representation

Answer 24

Audio file is recording the *“Loudness” of sound. The record of analog loudness in digital numbers is called Sampling

Question 25

Sampling Rate

Answer 25

How often the “Loudness” is recorded. Usually measure in Hz (times per second)
CD quality sound is recorded in 44.1kHz or 44100 times per second
The higher the rate, the better quality but more storage

Question 26

Sample Resolution (bit Depth)

Answer 26

How many “steps” the analog loudness is converted into digital numbers.
e.g. CD audio has 16-bit resolution, meaning that the loudness is recorded in 65536 discreet steps (2^16)

Again, the higher the sample resolution the better quality (and more storage)