Human Factors in HCI DesignHuman Factors in HCI Design

Cham, Tat-JenCham, Tat-Jen

Associate Professor / SMA-CS FellowAssociate Professor / SMA-CS Fellow

School of Computer EngineeringSchool of Computer Engineering

Nanyang Technological UniversityNanyang Technological University

http://www.ntu.edu.sg/home/astjchamhttp://www.ntu.edu.sg/home/astjcham

Pervasive Computing:Pervasive Computing:Technology-Centric ViewTechnology-Centric View

SMA5508 /MIT6.893Student

Python-GTK

GladeLinux

Intelligentagents

Bayesiannetworks

Smartrooms

Wi-Fi

Bluetooth3G

seamlesshandover

iPAQs /handhelds

Projection /OLED

displaysMixed-reality

systems

Speech recognition[speaker (in)dependent,isolated vs continuous speech,HMMs]

Computer vision[which really has nothing to dowith user’s visual system]

Grid computing

Security /data protection

Haptic Interfaces[force-feedback mechanisms]

Pervasive Computing:Pervasive Computing:Human-Centric ViewHuman-Centric View

Smith /Lim

When is my next appointment with John?

I’d really like to have a face-to-face conversation with Sarah in Europe, now

Isn’t that football game on now? I’d love to watch it

What are recent statistics of patients with the symptoms of Bob here?

What’s the fastest way home to get out of this traffic jam?

Heck, the pilot’s down with food poisoning. How can I land this plane?!

Human-Computer InterfacingHuman-Computer Interfacing

Physical Interface

Syntactic Interface

Semantic Interface

keyboards, mice, display, stylus,device form factors, microphone

shell commands + arguments, menus, icons, keyboard shortcuts, drag-n-drop, speech,

gestures, handwriting

dataflow, scientific visualization, financial accounting, remote communication

History of ComputersHistory of Computers

NotNot the usual stuff the usual stuffNumber of transistorsNumber of transistors

Faster speedsFaster speeds

Smaller sizesSmaller sizes

Power efficiencyPower efficiency

What about the user interfaces…What about the user interfaces…

History: Physical Interfacing 1History: Physical Interfacing 1

Abacus – 3000 BC

Pascalene – 1642

Babbage Difference Engine – 1832

History: Physical Interfacing 2History: Physical Interfacing 2

ENIAC – 1946

IBM 650 – 1953

DEC PDP-1 – 1960

History: Physical Interfacing 3 History: Physical Interfacing 3

Engelbart’s Workstation – 1966

TRS-80 / Apple II– 1978IBM PC – 1981

Xerox Star -- 1979Macintosh – 1985New iMac – 2001

History: Syntactic Interfacing 1History: Syntactic Interfacing 1

History: Syntactic Interfacing 2History: Syntactic Interfacing 2

History: Semantic InterfacingHistory: Semantic Interfacing

VisiCalc MS Excel

MatlabQuicken

The Attention DivideThe Attention Divide

Task Completion

Software Manipulation

Machine Operation

Task Completion

Software Manipulation

Machine Operation

Task Completion

Software Manipulation

Machine Operation

Early Era

Mid Era

Late Era

Enjoying Life

Task Completion

Software Manipulation

Machine Operation

Future?

HCI Design – Involving the UserHCI Design – Involving the UserDifficult to define HCI requirements specifications Difficult to define HCI requirements specifications before-handbefore-hand

Even harder in the pervasive computing eraEven harder in the pervasive computing era

Iterative rather than open-loop development Iterative rather than open-loop development processprocess

e.g. Star Model (Hartson & Hix, 1989) c.f. Waterfall Modele.g. Star Model (Hartson & Hix, 1989) c.f. Waterfall Model

PrototypingPrototyping

ImplementationImplementation Task / functionalanalysis

Task / functionalanalysis

Conceptual /formal design

Conceptual /formal design

Requirementsspecification

Requirementsspecification

EvaluationEvaluation

HCI Design GuidelinesHCI Design Guidelines

Reflexive (Motor-Sensory)Reflexive (Motor-Sensory)Minimize brain cycles needed to use the Minimize brain cycles needed to use the interface (“muscle memory”)interface (“muscle memory”)

CognitiveCognitiveAllows users to harness intuitive, Allows users to harness intuitive, problem-solving skillsproblem-solving skills

Social / OrganizationalSocial / OrganizationalMeet requirements for multi-person Meet requirements for multi-person interactioninteraction

Reflexive ConsiderationsReflexive Considerations

Intuition versus learningIntuition versus learningsimplicity versus completeness simplicity versus completeness / efficiency?/ efficiency?

Accuracy-speed tradeoffAccuracy-speed tradeoffROC curveROC curve

User feedbackUser feedbackvisual, aural, tactilevisual, aural, tactile

Motor-sensory channel Motor-sensory channel separationseparation

e.g. is gaze cursor control a e.g. is gaze cursor control a good interface?good interface?

ErgonomicsErgonomicsMinimize physical strain on Minimize physical strain on usersusers

Twiddler

HP Tablet PC

www.eyegaze.com

www.5dt.com

Reflexive Performance Studies: Reflexive Performance Studies: Evaluation and ModelingEvaluation and Modeling

Evaluations are typically based on timing Evaluations are typically based on timing experimentsexperiments

Keystroke-Level ModelKeystroke-Level ModelCard, Moran & Newell 1980Card, Moran & Newell 1980Task time = Task time = ΣΣ (unit tasks time) (unit tasks time)Unit tasks: Keystroking, Pointing,Unit tasks: Keystroking, Pointing,Homing, Drawing, Mental, ResponseHoming, Drawing, Mental, Response

Modified Fitts’ LawModified Fitts’ LawApplicable to pointing tasksApplicable to pointing tasks

Steering Law Steering Law ((Accot & Zhai 1997Accot & Zhai 1997))Navigation of menusNavigation of menus

1

thtarget wid

distancelogtime

movement2ba

Images from Buxton 2003

Cognitive ConsiderationsCognitive Considerations

MetaphorsMetaphorsInfo visualizationInfo visualizationVisual programmingVisual programmingAnthropomorphismAnthropomorphism

Cognitive loadCognitive loadFatigue, stress of taskFatigue, stress of taskautomation vs user choiceautomation vs user choice

Focus of attentionFocus of attentionmulti-taskingmulti-tasking

how easy is it to return to how easy is it to return to a suspended task?a suspended task?

User ModelingUser ModelingInterfaces tailored to Interfaces tailored to individualsindividuals

MSR data mountain

Khoros – Cantata

HP CRL –Smart Kiosk

Social and Organizational Social and Organizational ConsiderationsConsiderations

Synchronized experienceSynchronized experienceMassive multiplayer gamesMassive multiplayer games‘‘instant’ messaging, but typing instant’ messaging, but typing latency?latency?

Organizational orderOrganizational orderOnline roles and process flowOnline roles and process flowe.g. teaching groupware have e.g. teaching groupware have online roles for instructors, TAs and online roles for instructors, TAs and studentsstudents

Social normsSocial normsprivacyprivacy

instant messaging – should online instant messaging – should online state be revealed?state be revealed?what should default umasks be?what should default umasks be?

etiquetteetiquettetaking turns during tele-taking turns during tele-collaborationcollaborationsmileys – better or worse?smileys – better or worse?

America’s Army

Prototyping and EvaluationPrototyping and Evaluation

Wizard of OzWizard of Oz Prototyping PrototypingHuman `wizard’ to simulateHuman `wizard’ to simulatemachine interactionmachine interactionFaster prototypingFaster prototyping

eliminates programmingeliminates programmingoverheadoverhead

Usability StudiesUsability StudiesTask completion time, # errors / task, Task completion time, # errors / task, learning curve, function frequency learning curve, function frequency distributiondistributionUser satisfaction and feedbackUser satisfaction and feedbackPhysiological measurements?Physiological measurements?

Future ChallengesFuture Challenges

As computers and computing As computers and computing become pervasive…become pervasive…

what are the best interfaces?what are the best interfaces?how do we effectively move beyond how do we effectively move beyond keyboards, mice, screens, WIMP? Should keyboards, mice, screens, WIMP? Should we?we?

Interfaces thatInterfaces thatcombine cool technology, combine cool technology, andandsatisfy human-centric demandssatisfy human-centric demands

ReferencesReferences

Bill Buxton, Bill Buxton, Less is More (More or Less)Less is More (More or Less), 2001, 2001http://www.billbuxton.com/LessIsMore.htmlhttp://www.billbuxton.com/LessIsMore.html

J. Preece, Y. Rogers, H. Sharp, D. Benyon, S. J. Preece, Y. Rogers, H. Sharp, D. Benyon, S. Holland, T. Carey, Holland, T. Carey, Human-Computer InteractionHuman-Computer Interaction, , Addison-Wesley, 1994Addison-Wesley, 1994

Marc Rettig, Marc Rettig, Interaction Design History in a Teeny Interaction Design History in a Teeny Little NutshellLittle Nutshell, 2003, 2003

http://www.marcrettig.com/writings/rettig.interactionDeshttp://www.marcrettig.com/writings/rettig.interactionDesignHistory.2.03.pdfignHistory.2.03.pdf

CHICHI – ACM SIGCHI Conference on Human Factors – ACM SIGCHI Conference on Human Factors in Computing Systemsin Computing Systems