Unit 1_9Human Computer Interface
Why have an Interface?
The user needs to issue instructions
Problem diagnosis
The Computer needs to tell the user what to do
What do you need to Think about?
When designing an HCI you need to consider:
Task
User experience
User preference
Resources
General Features
Appropriate input methods
Use of colour
Consistency
Pictures/Icons
Text
Sound
Types of HCI
Command Line
Graphical user interfaces
Menu driven interfaces
Form driven interfaces
Natural language interfaces
Voice control
Graphical devices
Game playing
Touch sensitive screens
Biometric
Command Line
When computers were first created the lack of graphical abilities meant that all user interfaces were command line based.
Command Line
Advantages
Quicker that using a GUI for some tasks
More control for the user
Disadvantages
Very difficult for beginners
Have to remember loads of commands
Have to be very careful of syntax
EXAMPLE
Graphical User Interface
Graphical user interfaces utalise graphics in order to code commands with pictorial representation.
WIMP (Windows, Icon, Menus, Pointers)
Drag and drop
Task bars
WYSIWYG
Examples include Windows, LINUX, Snow leopard
EXAMPLE
Graphical User Interface
AdvantagesNo need to learn commandsIcons mean that novices can use the systemThe use of a mouse
DisadvantagesNeeds more powerful computersMore memory is neededCan be confusing using icons (undo)
Menu Driven Systems
Use a restricted list of commands that the user can select
AdvantagesFewer options mean less likely to make data entry errorsEasy systems to understand and useContext sensitive help can be providedUnsuitable choices can be hidden from the user
DisadvantagesOnly really suitable for systems that have a few possible optionsCauses frustration for experienced users
EXAMPLE
Form Driven Systems
Used to collect information from the user.
Advantages
Validation checks can be applied
Essential information can be forced (presence check)
Disadvantages
Only really has one purpose, gathering information from users.
Natural Language Interface
Allows users to use their own spoken language to communicate with the computer. Via microphone or keyboard.
Advantages
Very easy to learn
Disadvantages
Computers have real problems interpreting natural language (context, dual means etc)
Voice Interfaces
Uses voice recognition software to implement commands or input text onto a computerAdvantagesFaster than typing99% accuracyCheap
DisadvantagesNeeds trainingNot accurate at firstErrors due to background noiseNot compatible with all software
The reverse is called speech synthesis
Graphical Devices
The tablet and pen system (have a look at the interactive board). Great for drawing or fine detail work. E.g. graphics or CAD
Game Playing Devices
Joystick
Cordless games controller
Steering wheel
Car pedals
Gear sticks
Touch Sensitive Screens
Allows a user to make selections by simply pressing options presented on the screen. (The most famous example to date is the itouch or iphone!). Great for menu driven systems!
Biometric Devices
Retina Scan
Fingerprints
Hand prints
Voice
Face
EXAMPLES