ICT2 - Information: Management and Manipulation
User Interfaces
A "Human-Computer Interface" means the way in which the user interacts with the computer i.e. it is the method by which the user communicates with the computer. It usually means the screen display of the operating system and applications but it can also mean the choice of input device. "Human Computer Interaction" is a wider area that encompasses more than just the interface (e.g. health and safety issues). Throwing a brick at your computer is a type of human computer interaction that might occur if the interface is badly-designed!
The history of computing has seen three major types of interface, which are:
Command Line Interface (fast but complicated to remember commands/syntax)
Menu Driven Interface (still seen on many mobile phones)
Graphical User Interface (WIMP systems that are generally considered to be "user-friendly")
The WIMP Environment
Windows, Icons, Menus, Pointers
Windows is a WIMP environment. There is a common interface for most applications. The advantages of a common user interface are increased speed of learning and ease of use.
Windows facilitate multi-tasking. Windows should have scroll-bars and are usually resizeable.
Icons and buttons are useful for less-experienced users. More experienced users often prefer keyboard shortcuts. Universal symbols are often used (e.g. A question mark means Help). Buttons for obscure functions might be less easy to understand (Microsoft counters this problem with what they call "screen tips").
N.B. Don't confuse graphical user interfaces with the operating system. The operating system might provide a GUI but it does much more than that.
Menus
Pull-down menus (e.g. on the menu bar of Office applications.)
Pop-up Menus e.g. when you click the right mouse button. Also called a "context menu".
It is a useful feature to have commonly selected tasks at the top of a menu.
Natural Language Interface
Where a user can communicate with the computer in "Plain English". Unfortunately, the English language is ambiguous and many words have more than one meaning. (e.g. "Last night I shot a burglar in my pyjamas", "Dogs must be carried on the escalator.)
Ask Jeeves is an attempt at producing a natural language search engine.
Advantages are that there is no need to train people to remember special commands.
Disadvantages are that people find it difficult to speak in a grammatically correct way.
N.B. Do not confuse a natural language interface with a voice dictation system!
Forms and Dialogue Boxes
Entering data into a form is helpful because the user can see exactly what information he has to fill in. Points to consider when designing a form are:
Form should have a title
Should not be too cluttered
User should have a chance to correct any mistakes
"Exit" and "Help" buttons should be provided
There should be some indication of the length of data that can be accepted
Drop-down combo boxes
Radio Buttons/Checkboxes
Dialogue boxes are a special type of form the provide information often associated with Windows e.g. the Print dialogue box that asks how many copies, which pages to print, which printer to use, etc.
Speech Input (Voice Recognition)
Command and Control Systems: relatively small and cheap. Commands such as "Print", "Explorer", "Start" can be passed to the operating system.
Dictation Systems: Where a user can dictate to a word processor. The advantage is that typing is not needed. The drawbacks are:
software is expensive
software is heavy on system resources
software needs to be "trained" to recognise a particular voice/accent and even then often makes mistakes
Not suitable for busy offices
N.B. Don't confuse these two types of voice input system. Don't confuse voice input with a natural language interface.
Help
Online "Help" systems have gradually reduced the reliance on printed user manuals.
Help can be context-sensitive.
Dialogue Boxes
For a good example of a well-designed dialogue box, go to Microsoft Word and press CTRL+P. You might notice:
How the form appears uncluttered by having various options grouped together
Effective use of radio buttons and combo boxes
Clear Help, Quit, OK, Cancel options
The dialogue box has a title
More obscure features can be revealed by pressing "Options" or "Properties".
Error Message
Good error messages might have the following features:
Box should have a title
Sound alert might be useful?
Effective use of colour and an easily recognisable symbol (e.g. red stop sign or yellow warning sign)
Advanced information available by clicking a "More Info" button
Might include a hyperlink to take the user to an online knowledge-base
Obviously - a sensible jargon-free error message
Sound Output
This is where a computer can play a pre-recorded sound file to communicate with the user, instead of displaying a text message. For example, a printer driver could be programmed to play a sound saying "Please insert paper" instead of displaying a message box.
Colour
Choice of colour is important but be careful! Weak students often talk about the need for colours to be "attractive", to "go well together" or to "avoid clashing colours". Sensible things to say about choice of colour might be:
A very high proportion of men are red-green colour blind and this needs to be considered in interface design.
As a result of our psychological conditioning, we tend to associate red with danger and green with safety. Yellow is useful as a "warning" colour.
When people are staring at the same data input screen all day, it would be sensible to choose a colours that are not going to cause eye-strain.
Common User Interface
If an organisation chooses to purchase an integrated software suite, the common user interface would facilitate ease of learning and might reduce training costs.
Features that could be common include menus and buttons in the same place and common buttons for common options (e.g. Save, Print).
Types of Users
When designing the interface, the designer should consider the nature of the users involved e.g.
Child of primary school age (consider context keyboard, icons/buttons)
Blind person (braille printer, voice input/output)
Graphic Artist (large high-resolution display/graphic pad)
Cashpoint (ATM) machine (touch-screen more appropriate than a mouse)
Flight/Driving Simulator (consider choice of input device)
Good link on interface design: http://www.open2.net/ictportal/app/hci/hci.htm
Colour Blindness test: http://www.toledo-bend.com/colorblind/Ishihara.html
Interface Hall of Shame: http://www.rha.com/ui_hall_of_shame.htm