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
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