HumanComputer Interaction

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Human-Computer Interaction

• Introduction

BSc IMD Year I 2D Multimedia Authoring Semester
2 2002/03 Dr. Garry Patterson
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Human-Computer Interaction 1 Aims

• Knowledge of HCI
• Some practical analysis and design skills
• Practical implementation of GUIs
• Enable you to assess how HCI may be incorporated
  into software lifecycle
• Personal transferable skills

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Information, Slides, Notes Software on WWW
Server
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Lecture Overview

• Course outline
• Background and aims of HCI
• Usability
• Rise in importance of
• Interactive Systems
• Graphical User Interface (GUI)
• The Web - the global GUI

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The Parts of User Interface Development
Development of the user interface
Constructional
Behavioural
Development of the interaction component
Development of the interface software
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Disciplines Contributing to Human-Computer
Interaction
Computer Science
Cognitive Psychology
Human-Computer Interaction
Graphic Design
Artificial Intelligence
Ergonomics and Human Factors
Sociology
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Central Aim and Approach of HCI
Aim To optimise performance of human and
computer together as a system

• Approach User-Centred
• Users should not have to adapt to the interface
  the interface should be intuitive and natural for
  them to learn and to use.
• Talking to users is not a luxury, its a
  necessity

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Software Quality (ISO 9126)

• Functionality
• Reliability
• Usability
• Efficiency
• Maintainability
• Portability

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Requirements Gathering
User Requirements
Functional
Data
Usability
Learnability
Throughput
Flexibility
Attitude
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Usability

• For Specified user and specified task
• Learnability
• Ease of learning
• User retention over time
• Throughput -
• High speed of user task performance
• Low user error rate
• Flexibility
• Freedom of object / action selection
• User expertise levels
• Attitude - subjective user satisfaction

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Microsoft and Quicken

• 1995 - Microsoft tries to purchase Quicken from
  Intuit for 1.5 billion
• Reason for attempted purchase Quicken more
  usable than Microsofts own product

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Mitchell Kapor (Designer of Lotus 1-2-3)Quotes
from A software Design Manifesto 1990

• The lack of usability in software and the poor
  design of programs are the secret shame of the
  software industry.
• One of the main reasons most computer software
  is so abysmal is that its not designed at all,
  but merely engineered.
• ... implementors often place more emphasis on a
  programs internal construction than on its
  external design.
• (Reprinted in Bringing Design to Software, T.
  Winograd, 1996, Addison Wesley)

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UsabilityTransparency

• Relationship between
• users goals
• required actions
• results
• must be meaningful,
• not arbitrary

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Problems with ATMs

• Older people make much less use of ATMs
• 24 year olds average 7 visits to an ATM per
  month
• Use drops off among those over 45
• 65 years two-thirds NEVER use an ATM
• Senior citizens often put off by ATMs because
  they find the machines complicated, inconvenient
  and intimidating.
• Buttons that didnt line up with commands
• Dimly lit screens hard to read in the glare of
  daylight
• Sometimes confusing menu choices

Source http//cnn.com/TECH/9712/04/t_t/atms.senio
rs/index.html Reporting on research by W. Rogers
and A. Fisk, Georgia Institute of Technology
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Problems with ATMs (Continued)

• Researchers and banks expected ATMs to be
  intuitively easy to use
• Testing among senior citizens found only 20
  percent correct operation
• For example, one man tried to withdraw 30. He
  entered the amount he wanted incorrectly because
  the directions -- calling for "multiples of 10"
  -- confused him
• Usability suggestions
• Simpler on-screen instructions
• More "undo" buttons
• Banks should provide training for any customers
  who need it
• A "large percentage" of people they surveyed said
  they would use ATMs if trained

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Poor interface may cause

• Increased mistakes in data entry and system
  operation
• Inaccessible functionality
• User frustration low productivity and/or under
  utilisation
• System failure because of user rejection

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Poor interface may cause

• Increased mistakes in data entry and system
  operation
• Inaccessible functionality
• User frustration low productivity and/or under
  utilisation
• System failure because of user rejection

Nearly half of entire software development effort
relates to the user interface. (Myers and Rosson,
1992)
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Rise in Importance of Usability
Research machines 1950s Mathematicians Machine
reliability
Scientists users do
programming Mainframes 1960s Data-processing Use
rs of output (business
professionals managers) grow
1970s disenchanted
with delays,
costs and lack of flexibility Minicomputers 19
70s Engineering and Users must still do must
other non-computer program
ming usability
professionals becomes a problem Microcomputer
s 1980s Almost anyone Usability is the major
problem
Shackle, 1991
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ENIAC 1943 Research Machine
(U.S. Army Photo)
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IBM Mainframe 1960s
(Photograph courtesy of the IBM archives)
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Minicomputers 1970s and 1980s
U.S. Army Photograph, courtesy of Michael John
Muuss,
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Microcomputers 1970s - 1990s
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PC Processor Performance Trends
Pentium II
10 GHz-bit
Pentium
Processor Performance
486DX2
1 GHz-bit
486DX
386DX
80286
100 MHz-bit
8088
8080
10 MHz-bit
1 MHz-bit
100 KHz-bit
1970 1980 1990
2000

• Current situation after functional needs are
  fulfilled, still plenty of capacity to support
  highly interactive user interfaces

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CPU Development EffortSeptember 1997

• Intel, AMD and Motorola invest 250m to form new
  company, EUV LLC, working in partnership with
  some US government research facilities.
• Aim to develop ultraviolet etching technology to
  place 1000 million transistors onto a chip by
  2011. (Pentium II has 7.5 million.)
• CPUs 100 times more powerful
• Memory chips 1000 more storage capacity

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Hard Disk Drive Trends

• Capacities up
• Costs down
• Affordable support for multimedia applications

Anticipated 3.5 inch 14Gb drive by 1998
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GUIs in the 1990s
The pervasiveness of graphical user interfaces
(GUIs) is a clear sign that all software of the
future must address the users needs for ease of
use. IEEE Software, Nov 1990
A very rich design medium
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Browser is Becoming theNew Graphical User
Interface
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Benefits of GUIs over Text Interfaces

• User completes tasks faster
• Lower frustration e.g.
• Less modal operation
• Easy interleaving tasks
• Perceived lower fatigue
• Better able to self-teach - Reduced training
  costs
• Better able to learn more capabilities of
  applications

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The Web The Global GUI

• Exponential growth
• Interactive multimedia and E-commerce
• HTML being enhanced with Extensible Markup
  Language (XML)

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Lecture Review

• HCI and other subject areas
• User-centred
• Usability
• Faster CPUs / bigger disks support highly
  interactive systems
• Benefits of GUIs
• The Web - the global GUI