ICT
- Created by: Daniel Wright
- Created on: 09-04-13 13:24
Methods to convey information
Text
Advantages:
Most people can read and understand text
Disadvantages:
May be in a language that someone doesn't know
Graphics
Advantages:
Many signs universal and easilY recognisable
Disadvantages:
Signs may be too vague
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Sound
Advantages:
Visually impared can also understand it
Disadvantages:
Hearing impared cannot understand
Video
Advantages:
Pulls together sound and image allowing most people to understand
Disadvantages:
Have to watch entire video to find out certain piece of information
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LED
Advantages:
Attracts attention to get more to read it
Disadvantages:
If LED lights break the sign may become unreadable
Data types
Boolean- m/f, t/f, yes/no
Real- any number with a decimal place
Integer- whole number
Text/string- multiple characters together
Date/Time- texts and numbers with symbols
Currency- money
Static and dynamic
Static- once created it cannot be changed- e.g. a programme on a disc
Dynamic- can be changed e.g data on a website
Advantages of static:
Available more easily- printable
Most likely proof read
Disadvantages of static:
If mistake is made then mistake in all copies
Any changes will make current version out of date
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Advantages of dynamic:
If mistake is made can be corrected
Cost of updating far less
encoding
Encoding- data in simplier form
Encryption- putting data into secret code
Advantages of encoding:
More accurate and reliable
most useful where choices of response is small e.g. male/female
Disadvantages:
not completely useful when capturing answers that require value judgements
Can lead to misenterpretation
Verification and Validation
Validation- process of ensuring data is sensible, usually by applying rules
Verification- happens after data has been entered, usually by entering data twice
VALIDATION DOES NOT STOP PEOPLE FROM MAKING MISTAKES!!!!
Transcription errors
Tend to happen when data is entered manually
Data capture forms:
majority of errors by human error
Data capture reduces this
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Examples of data capture:
Barcode readers
Sensors
Touch tone phone
Validation checks:
Lookup list check: data only allowed from list
Batch header check- total number of record is counted and compared with batch header
Modulus 11
Rules:
Each number in barcode is given a weight starting from 2 and increasing from right to left
Each number then timesed by its weight
All results added together
Number then divided by 11
Number then taken away from 11 to give final answer
Exceptions:
If remainder (after dvided by 11) is 0, then check digit is 0 not 11
If remainder is 1, is x not 10
IPOS
Input
Process
Output
Storage
Feedback
hardware
GUI- graphic user interface- interface based on graphics and pictures rather than text
WIMP- windows icons menu pointer particular type of GUI
wizards,style sheets etc
Wizards- assists user to produce final product. offers user a range of screens where they can make choices and enter info.
Advantages:
- Save time form inexperienced users
- ensure that no important info is forgotten
-Standard formats can be used
- element of user friendliness
Disadvantages:
- No individuality to the end result
- End result may not meet needs
- Harder for documents to be tailored to meet needs of the target audience
-
style sheets
Similar to templates and are used to set out layouts. usually relate to word processing or DTP
Elements in style sheets:
-Font size
-Font Style
-Margin Size
-Alignement
Advantages:
-Lack of confusion
-Different people can work on different parts of same document and because of the style sheet the results will be consistent.
-
Disadvantages:
-Someone needs to develop style sheet before it can be used as template
-Can be restrictive
Templates
Provides standard pre-set layouts and formats
Includes:
-Page formatting
-Text inserts
-Graphical inserts
-Character formatting
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Advantages:
-Faster than creating manually
-Easier to use than style sheets
Disadvantages:
-Less control
-Not as unique
Macros
A set of stored commands that can be relayed by pressing a button
Advantages:
-Repetitive task can be repated with ease
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-Errors may be reduced
-Inexperienced users can perform complx tasks
Disadvantages:
-Errors may occur when macro is run differently than pre-recorded
-Users must know and remeber key combination
Design considerations for tailored data- entry scr
Design considerations- user friendly
Consistency- Several forms then user will expect buttons to do similar things
Relevancy- should not ask for redundant information
Supportiveness- needs to be a balance
Visual and audibal cues- needs to be feedback
standard/generic applications
Buttons:
Can be used to take user to another page or to run selected action/command
Forms:
Can be use in assistance in data entry. can give advice and guidance
ads and disads of standard/generic applications
advantages:
-Simplification of user data entry
-Time taken to enter data sped up
- data entered can be validated
Disadvantages:
-Technical knowledge needed to create and test the interface
- if software on interface is updated no guarentee that interface performs like it is supposed to
- if problem occurs with the interface or option is not available on button then user may not be able to complete task.
consistent house style
Advantages:
- easily recognisable
-Devlops and reinforces company
-Quicker-template
- Save money
- More Control
Disadvantages:
-If look is changed, harder to recognise
-Costs a lot of money to change/advertise
Modelling software
Used to create virtual representation of item within the computer
Why is it used?:
-less risky to test a model of a design than to create it in reality
- computer model can be backed up and shared
- can be accelerated or slowedc down to see effects.
how are features used in modelling software
Variables- associated with particluar cell (e.g. D4)
Formulae- way a calculation is represented in a spreadsheet
Rules- set of procedures that must be followed
Functions- used to represent a formula that is too complex
cell referencing
Relative cell referencing- where cell referenced in a spreadsheet formula changes when formula is copied to other cells.
Absolute referencing- used when a referenced cell in a spread sheet formula needs to remain exactly the same when the formula is copied to other cells.
ads and disads of spread sheet simulations
advantages:
-Automatic re-calculation
- graphs can be produced
- model can be saved and backed up
- computer models can be sped up or slowed down
Disadvantages:
-model may not be an accurate representation of real world
-may be time consuming
- many variables need to be considered
Data protection act
Data subject- the person the data is about
Data controller- person within company responsible for making sure act is being followed
Data processor- any person who processes the data on behalf of controller
Recipient- individuals given data in order to process it
Third party- Receives data for processing
Information commisioner- individual making sure DPA is being followed by all companies
Rights of the individual:
-Allowed access
- Prevent information being kept which may cause damage or distress
- Right to prevent information for marketing
- Right to compensation if damage or distress is caused
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Main aspects:
1) Processed lawfully and fairly
2) Obtained only for one or more specified and lawful purposes
3) Shalle be adequate
4) Shall be accurate and kept up to date
5) personal data processed for an purpose shall not be kept longer than needed
6) Shall be processed in accordance with the rights of the data subject
7) Appropriate measures will be taken against unauthorised or unlawful processing
8) personal data shall not be transferred to a country or territory outside the EU.
Computer Misuse Act
4 provisions:
1) Unauthorised access to computer material- entering the system
2) Unauthorised access with intent to commit or facilitate the commission of further offences- apart from entering system
3) Unauthorised acts with intent to impair, or with recklessness as to impairing operations on a computer- making changes to content
4) Making, suppyling or obtaining articles for use in offences- malicious scripts that will modify original script
Advantages:
- Act allows companies a legal recourse if their security has been comprimised
Disadvantages:
-There has to be intent
-The act is enforced only when a crime has been committed
- Hard to track the intruder
The copyright, designs and patents act
The act makes it illegal to steal or create unauthroised copies of software
Advantages:
- a lot of effort goes into publications, they deserve to be rewarded
Disadvantages:
- When you buy software, you buy the online license to use it
-Understanding license can be difficult and many mistakes are made
The regulation of Investigatory Powers Act
The act was introduced to address concerns about the use and misuse of communication interception techniques
Advantages:
-Can monitor what employees or users are doing
- Can ensure that facilities are only being used for legitimate work
Disadvantages:
- Any form of monitoring may be seen as a breach of trust
-Could be seen as going against that desire of privacy
The electronic communications act
Allows goverment to set up a 'register' and allows to recognise digital signatures
Benefits:
- Increased security
Problems:
- Coveyancing and wills are two areas digital signatures will take a long time to be introduced
The freedoms of information act
Deals with access to official information
Benefits:
- Information that was not accessible to the public is now available
Problems:
- Just because access is requested does not mean it will be granted
- Public authority does not have to confirm or deny the existance of information requested
characteristics of documents
-footnotes- appear at bottom of page
-Sections- chapters
- Frames-text box
Mail merging
Disadvantages:
-May seem impersonal
- Can create more errors
- doesnt suit every circumstance
key words
Hotspot- area of an image that is a link
Buttons- used to complete an action/command
accitate
Advantages:
- Hard copy
- No hardware problems
Disadvantages:
- Harder to correct errors
- Cant change colours
health problems
Repetitive strain injury- Doing to much in one movement- Sit in correct seating position, gel rests, footrests
Fatigue- Continuos period of mental work- breaks, holidays
Stress- State of mental strain- Time off, therapist
Back ache- Uncomfortable furniture, Poor posture- Medication, massage, rest
Deep vein thrombosis- Blood clot- Walk/move around
Carpel tunnel syndrome- Pressure on the median nerve in wrist- Breaks, avoid repetitive actions
Ulnar neuritis- Compression of ulnar nerve in elbow- correct desk height, arm rests
Normalisation
1NF
- a table is 1NF if every data value in a field is atomic and each record does not contain repeating data.
-ATomic means that the data value cannot be broken down any further. e.g. 'Student Name' is not atomic because it contains both the first name and last name.
2NF
- a table is 2NF if it is 1NF and all its non key attributes are dependent on the entire primary key
3NF
- a table is 3NF if it is 2NF and there is no functional dependancy between non-key items
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Advantages:
- Final tables will have no redundant data
- a normalised data structure is easier to maintain
- data at end stored in an effective structure
Disadvantages:
- reduced database performance
- database that are required to store historical data must break the rules of normalisation
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