Human Computer Interface (HCI)
Computer Systems in which Humans and
Computers interact
Different Types of HCI
•CLI
•Menu Driven
•GUI
•NLI
Command Line Interface (CLI)
• Text based
• User types commands and computer carries out when
enter key pressed
• E.g. Windows Command Prompt
Advantages
• Good for expert users
• Uses few resources
• Very flexible
Disadvantages
• Requires user to learn commands – bad for novice users
• Hidden features
Menu Driven Interfaces
• Uses menus to communicate with user
• Advantages
– No need to learn complex commands
– Easier for novice user to learn than CLI
– Ideal if there are limited options
• Disadvantages
– User interface limited by screen space
– Can frustrate expert user
– Does not have visual elements of GUI
Graphical User Interface (GUI)
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Combines pictures & text
Accepts input via devices such as keyboards & mouse
Offers graphical icons and visual indicators
E.g. Microsoft Windows
• Advantages
– Intuitive and easy to navigate (sounds, pictures incorporated)
– Good for novice users
• Disadvantages
– Resource hungry – can be slow on old machines
– Hidden commands must be found using help
Natural Language Interface
• Verbal commands given to computer
• Advantages
– Very easy for novice users
– Quick
– Hands free (can be used by people with
disabilities)
• Disadvantages
– Can be unreliable
– Can “interpret” incorrectly (dialect)
HCI Questions
• Explain the meaning of the term ‘humancomputer interface’ (2)
• Describe a human-computer interface that
can be used with a particular type of
disability (4)
Designing an Effective HCI
Designing An Effective HCI
• Consideration should be given to:
– Use of colour
– Font size
– Layout
– Navigation
– Consistency
– Help
– Use by people with disabilities
Questions
• Name four factors which must be taken
into account when designing a good user
interface. Explain why each factor is
important. (8)
• Explain one way in which the needs of an
expert user and a novice user can be
accommodated when designing the HCI
for a piece of software. (2)
Input Devices
• Touch Screens (ATMs, POS)
• Joystick
• Iris recognition / hand prints
Biometric Devices
• Iris Recognition
• Hand Prints
• Advantages
– Difficult to forge
– No smart cards to lose
• Disadvantages
– Human rights?
– New technology = little trust & bugs in system