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)

• 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 ‘human-computer 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