A2 LEVEL ICT

5.7 Human/Computer Interface Reading and Notes: Ch 30 (ICT 2 revision) + Ch 61

Why Do We Need to Consider the HCI?

Good HCI means that new systems are easy to use and users are productive and make fewer mistakes.

System designers must think about:

Who will the users be - primary school children or brain surgeons?

What tasks will the system be doing?

What environment will the system be used in - noisy (factory), quiet (office), changeable (paramedics change their environment and location every half an hour).

What is technologically possible (voice data entry)

They then design a system for those users which uses appropriate:

Input and output devices

Navigation

Validation

Error messages and help

TASK 1 Answer the following questions:

  1. List three different input devices and state an appropriate use for each.
  2. List three different output devices and state an appropriate use for each.
  3. What does the term 'validation' mean?
  4. Explain two different validation methods.

Interface Styles

1. Command Line Interface

TASK 2 Explain three advantages and three disadvantages of using a command line interface.
2. Full Screen Menu Interface

3. Form based data Entry

TASK 3 Explain two disadvantages and two advantages of using forms for data entry.

4. Graphical User Interface (GUI)

Makes the computer as user-friendly as possible by using graphics, icons and pointers (mouse, trackball etc).

Features of GUIs

Uses the WIMP interface. Windows, Icons, Mouse, Pull-down (or Pop-up) menus.

Pull Down Menus

Windows

WYSIWYG (wizzy-wig) What You See Is What YouGet

  • What you see on screen matches what is printed.
  • Used on word processors and DTP packages.
  • Used to be different - you had to put codes in to denote Bold, Italic, Underline.

TASK 5 List two advantages and two disadvantages of GUIs

5.Natural Language Interface

Humans communicate in natural language, e.g. English.

  • Computers respond to a small number of precise commands and do not understand ambiguous language.
  • Ask Jeeves is a good example. Users ask Jeeves questions in plain English and receive links to appropriate websites.
  • Easier to ask for 'A list of student s who need to resit a module than using SQL :

SELECT [Student test result].[Student Number], Student.[Last Name], Student.[First Name], Student.[Tutor Group], Test.[Test Number], [Student test result].Pass

FROM Test INNER JOIN (Student INNER JOIN [Student test result] ON Student.[Student Number] = [Student test result].[Student Number]) ON Test.[Test Number] = [Student test result].[Test Number]

WHERE ((([Student test result].Pass)=No));

Problems with Language

Language is ambiguous:

Are Lynn and Mike married?

Are Lynn and Ian married?

The same word can have different meanings

Did Shrewsbury Town win any matches this season?

TASK 6 Explain two advantages and two disadvantages of a natural language interface.

Resource Implications

GUIs and Windows are user-friendly, but they need better and faster computers. We could not have such systems running on old computers (that Lynn used at Sixth Form!!!).

Operating System / Capabilities / Minimum Requirements
MS-DOS 6 (1981) / Command line interface (with some extras) / Processor 486 (clock speed 10Mhz)
RAM 512 Kb
Hard drive space 5Mb
Windows 2000 / GUI
Internet capability / Processor 133Mhz
RAM min 64Mb
Hard drive space 650Mb
Windows XP / As 2000 + networking, movies, music etc / Processor 300Mhz
RAM min 128Mb
Hard drive space 1.5 Gb

TASK 7 Explain why the newer software (GUI) needs:

  1. Faster processor
  2. Greater RAM
  3. Greater Hard drive space

than the old command line systems.

We now also look for extra hardware:

Larger VDUs for the graphics

Modem for the Internet

Camera for video conferencing.

For information about how computers have changed over time, look at:

Customising Software Packages

Certain software packages allow the user to choose toolbars and icons to be used and menus can be altered to meet specific needs.

Word will allow you to create a personal dictionary.

You can change our desktop to include icons on that you want to have (and Wallpaper!!!).

You can switch toolbars off to hide unwanted functions from an inexperienced user - remember the AutoExec macro in Access? Other software allows you to do the same.

TASK 8 Look in the Word help file for 'Accessibility'. What features does Word have to cater for the user with special needs?

TASK 9 Look in Word help and search for 'Create a new Custom Dictionary'. What sort of user may want to create a personal dictionary and why?

EXAM TYPE QUESTIONS

1. (June 2002, Q6)

  1. Describe two factors that need to be considered when designing for human/computer interaction. (4)
  2. Describe two resource implications of providing an effective interface. (4)
  3. Some users may customise their interface. Describe one consequence this may have for support staff when providing technical assistance. (2)

2. (Jan 2003, Q8)

A mail order music company has decided to expand and has established a retail outlet in a busy shopping centre.

  1. An important feature of the mail order system is the interface for the staff who use it. State three features you would expect the human/computer interface to have in such a system and give a different reason for each one. (6)
  2. (i) Name an appropriate device for capturing data on each item that is sold via the retail outlet (1)

(ii) Describe one advantage for the company of using this device. (2)

3. (June 2001, Q 8)

For each of the examples given below state, with reasons, three features that you would expect each of the following Human Computer Interfaces (HCI) to have.

  1. HCI for a machine tool operator in a factory which, for example, produces car parts.
  2. HCI for a graphic designer, for example, someone who produces artwork for publication in magazines. (12)

4. A local primary school has asked you to develop a spreadsheet times table application (five and ten times table only). They want the students to guess the answer and for the spreadsheet to tell them if they are correct.

The students are aged 5-7 and many of them have reading difficulties.

  1. List two appropriate input devices and explain why you would use them in this situation. (4)
  2. List two appropriate output devices and explain why you would use them in this situation. (4)
  3. State three features you would expect the human/computer interface to have in such a system and give a different reason for each one. (6)

5. How does an Integrated package make it easier for the occasional user to learn a new program? (3)

June 2002 Q6.(a) Describe two factors that need to be considered when designing for human/computer interaction.

User friendlyMaking the system accessible to the widest audience/ Use icons in a meaningful way, so that users are not frustrated/ Have easily navigable screen layouts/ Provides a consistent look and feel so that skills are transferable between packages/ So that the system is intuitive so that the user feels comfortable and the system is easy to learn how to use.

Help mechanismsUsing context sensitive help means that the user has a consistent method of getting aid/ Use of wizards can help users to complete most parts of a complex task by guiding them through the required stages/ Use of tips/assistants can point out alternative methods of completing a task that may benefit the user/ Built in demonstrations can show users how to complete unfamiliar tasks/ Error messages provided by the system should not only be of assistance to programmers, but also to end-users so that they can see what has gone wrong and why

Short cutsOnce a user is familiar with a process/piece of software they want to complete tasks efficiently/ In order to support productivity, users should have the facility to customise toolbars/menus so that commonly used tasks are easily accessible/ The ability to use alternative input methods for commands such as ctrl-P for print can aid efficiency.

Long-term memoryUse standard menu items/key strokes will help the end-user by reducing the amount of time needed to learn how to use a package

(1))Describe two resource implications of providing an effective interface.

Capacity of Backing Store/Hard Disk

  • Operating system (OS) will consist of large graphics files that require storing.
  • Comprehensive help Systems will have a large number of files to be stored.
  • Programs that operate in an environment such as a GUI will tend to be complex in terms of how they have been programmed, and so tend to be large.
  • Documents created my users may contain lots of e.g. format information/graphics that may not conveniently be stored on removable media.

Capacity of immediate Access Store/ main store/RAM

  • Complex graphics will take up a lot of space in IAS when they are being used, due to bitmapped images
  • When help facilities are being accessed (wizards, demos, help files), these need to be stored alongside OS, application and data in LAS in order to be of use.
  • In order for multi-tasking to take place, as when a task is not being accessed it has to be stored where it can be accessed immediately

Speed of processor/Clock speed

  • If the processor is slow, graphics will not be produced smoothly
  • Users may get frustrated waiting for systems to complete tasks.
  • Multi-tasking involves the processor working at a high rate.

(c)Some users may customise their interface. Describe one consequence this may have for support staff when providing technical assistance.

More time will be taken up in support (1) as staff will have to identify which icons perform which task/ the position of icons to perform tasks (1)

Changes made by the users may have other consequences (1) and this may be difficult/ impossible for the support staff to assess without access to the user's system

(1)

Workers that share desks don't recognise the environment (1) and support staff are not aware of what has been changed (1)

Etc.Max (2,1,0) 10 Marks

Jan 2003 a)

  • Cater for different levels of user expertise (1) workers may not be very IT literate (1)
  • Cater for different end user's physical abilities (1), e.g. for partially sighted (1)
  • Consistent at both sites (1) so staff do not have to learn two systems (1)
  • Sensible use of colour (1) as the system will be used intensively (1)
  • Help features accessible (1) so that the users are able to assist themselves (1)
  • Menu based system (1) so that input choices are restricted to items sold (1)
  • GUI (1) to build on previous experience/ avoid language issues etc (1)
  • Automated data entry (1) to reduce errors (1)

b) Barcode scanner or keyboard

c) Barcode scanner

  • simple method (1) minimal training so staff can work quickly
  • stock is provided with barcode from supplier (1) so little extra work required in preparation (1)
  • speed of data capture compared to other methods (1) so store increases productivity (1)

Keyboard

  • Cheap method compared to scanner (1)
  • Simple method (1) so minimal staff training needed (1)

June 2002, Q 8

(a)

  • menu drive (1) due to a restricted number of operations available to the operator (1)
  • unambiguous error messages (1) for safety reasons (1)
  • character only display (1) operator does not need graphical output (1)
  • restricted input device (touchscreen/trackball/number keypad) (1) does not need keyboard (1)
  • safety features (1) + e.g. (1)

(b)

GUI (1) due to diverse nature of the task (1)

Ability to zoom (1) so detail and overall image can be viewed (1)

Multiple windows (1) so the same object can be viewed in many ways

Many input and output devices (1) for inputting text and images (1)

Ability to adjust screen resolution (1) + reason (1)

Lynn Daddo-Langlois1

5.7 HCI-Human Computer Interface