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