Download ppt - 1 Introduction Human-Computer Interaction. 2 Human-Computer Interaction: Aims Knowledge of HCI Some practical analysis and design skills Practical implementation

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Introduction

Human-Computer Interaction

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Human-Computer Interaction: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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Lecture Overview

• Background and aims of HCI

• Usability

• Rise in importance of

• Interactive Systems

• Graphical User Interface (GUI)

Human Computer Interaction - HCI

Association for Computing Machinery (ACM) defines human-computer interaction as

"a discipline concerned with the design, evaluation and implementation of interactive computing systems for human use and with the study of major phenomena surrounding them.”

Goal of HCI

Basic goal of HCI is to improve interactions between users and computers by making computers more usable and receptive to user's needs. Specifically, HCI is concerned with:

• methodologies and processes for designing interfaces (i.e., given a task and a class of users, design best possible interface within given constraints, optimising for a desired property such as learnability or efficiency of use)

• methods for implementing interfaces (e.g. software toolkits and libraries; efficient algorithms)

• techniques for evaluating and comparing interfaces

• developing new interfaces and interaction techniques

• developing descriptive and predictive models and theories of interaction

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Course Outline: HCI and the Software Lifecycle

Problem statementProblem statement

ImplementationImplementation

U s

e r

P

a r

t i

ci

p a

t i

o n

Defin

ition

An

alysis

Desig

n

User object modellingUser object modelling

Requirements spec. (inc. usability specs.)Requirements spec. (inc. usability specs.)

Interaction design / Presentation designInteraction design / Presentation design

Systems Analysis (inc. user and task analysis)Systems Analysis (inc. user and task analysis)

Evaluation (Analytical, Empirical)Evaluation (Analytical, Empirical)

UserUser’’s conceptual model design / Interaction styles conceptual model design / Interaction style

Prototype (inc. online help)Prototype (inc. online help)

System design spec. (inc. Interface design spec.)System design spec. (inc. Interface design spec.)

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The Parts of User Interface Development

Development of the User Interface

Development of the interaction component

Development of the interface software

ConstructionalBehavioural

Disciplines

Contributing

to Human

Computer

Interaction

Computer Science

Cognitive Psychology

Artificial Intelligence

Human Computer Interaction

Graphic Design

Sociology Ergonomics and Human Factors

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Central Aim and Approach of HCI

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, it’s a necessity”

Aim: Aim: To optimise performance of human To optimise performance of human and computer together as a and computer together as a systemsystem

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User Centred Design

WorkWork

PeoplePeople TechnologyTechnology

EnvironmentEnvironment

User Centred Design

• User-Centred Design (UCD) or Pervasive Usability is a design philosophy and a process in which needs, wants, and limitations of end users of a product are given extensive attention at each stage of design process.

• UCD can be characterized as multi-stage problem solving process that not only requires designers to analyse and foresee how users are likely to use a product, but also to test the validity of their assumptions with regards to user behaviour in real world tests with actual users.

• Chief difference from other product design philosophies is that UCD tries to optimise the product around how users can, want, or need to use the product, rather than forcing the users to change their behaviour to accommodate the product.

User Centred Design Principles

• Early focus on users and tasks • Structured and systematic information gathering

(consistent across the board)

• Designers trained by experts before conducting data collection sessions

• Empirical Measurement and testing of product usage

• Focus on ease of learning and ease of use

• Testing of prototypes with actual users

• Iterative Design • Product designed, modified and tested repeatedly.

• Allow for the complete overhaul and rethinking of design by early testing of conceptual models and design ideas.

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Software Quality (ISO 9126)

• FunctionalityFunctionality

• ReliabilityReliability

• UsabilityUsability

• EfficiencyEfficiency

• MaintainabilityMaintainability

• PortabilityPortability

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Requirements Gathering

User RequirementsFunctionalDataUsability Learnability

ThroughputFlexibilityAttitude

Usability

Bailey’s Human Performance Model

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

• Participatory Design• Paper Prototyping / Storyboarding• Cognitive Walkthroughs• Usability Testing• Heuristic Evaluation

• Usability Testing• Heuristic

Evaluation• Follow-up Studies• Compare To

Benchmarks

• Usability Testing• Focus Groups• Participatory Design• Surveys• Heuristic Evaluation• Set Benchmarks

Source: Based Upon Rubin, et al. “Handbook of Usability Testing: How to Plan, Design, and Conduct Effective Tests”

Usability Testing

When It Goes WrongRubin et. al. * have identified five reasons why products, especially technology focused ones, are typically hard to use. These are:

• Focus on the device or system during development

• Changing and adapting target audience

• Trivialising designing usable products

• Non-integrated working of specialist teams both internally and with each other

• Design and implementation does not always match.

* “Handbook of Usability Testing: How to Plan, Design, and Conduct Effective Tests” by Rubin, Chisnell and Spool

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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 Microsoft’s 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 it’s not designed at all, but merely engineered….”

“... implementors often place more emphasis on a program’s internal construction than on its external design.”

(Reprinted in ‘Bringing Design to Software’, T. Winograd, 1996, Addison Wesley)

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Usability

Transparency

Relationship between

• user’s 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 didn’t 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.seniors/index.htmlSource: http://cnn.com/TECH/9712/04/t_t/atms.seniors/index.htmlReporting on research by W. Rogers and A. Fisk, Georgia Institute of TechnologyReporting 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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Example: Lack of Transparency

Old UU phones:

Call Diversion Instructions

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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 machinesResearch machines 1950s1950s MathematiciansMathematicians Machine reliabilityMachine reliability

ScientistsScientists users do programmingusers do programming

MainframesMainframes 19601960’’ss Data-processingData-processing Users of output (business Users of output (business & & professionalsprofessionals managers) growmanagers) grow

19701970’’ss disenchanted with delays,disenchanted with delays,

costs and lack of flexibilitycosts and lack of flexibility

MinicomputersMinicomputers 19701970’’ss Engineering andEngineering and Users must still do mustUsers must still do must

other non-computerother non-computer programming; usability programming; usability

professionalsprofessionals becomes a problembecomes a problem

MicrocomputersMicrocomputers 19801980’’ss Almost anyoneAlmost anyone Usability is the major Usability is the major

problemproblem

Shackle, 1991Shackle, 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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Desktop & Multimedia Internet Ready PCs Towards Pervasive / Ubiquitous Computing: 2005 - . . .

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The Leading Trend in Software

““Rise of GUI. The Rise of GUI. The

pervasiveness of graphical pervasiveness of graphical

user interfaces is a clear sign user interfaces is a clear sign

that all software of the future that all software of the future

must address the usersmust address the users’’

needs for ease of use.needs for ease of use.”” IEEE Software, Nov 1990IEEE Software, Nov 1990 A very rich A very rich

design mediumdesign medium

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Browser the ‘New’ Graphical User Interface

Windows 8 – Pervasive Computing But Less Control

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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

Recommended Further Reading


© Gary Larson

Advanced Common Sense SM http://www.sensible.com


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Lecture Review

• HCI and other subject areas

• User-centred

• Usability

• Faster CPUs / bigger disks support highly interactive systems

• Interactive systems pervasive

• Benefits of GUIs