Principles of User-Centered DesignWhat is design?ApproachesUser-Centered DesignMethods for UCDSoft Systems MethodologySSMStages in SSMSSM, “root definition”Slide 10Slide 11Cooperative DesignOSTASlide 14OSTA – Systems Analysis (top)OSTA – technical and socialProblems:MultiviewSlide 19Slide 20Star Life CycleThe Star Life CycleSlide 23Slide 24Example: Olympic Messaging Service (1984 Los Angeles Olympic Games)OMS - ProcessSlide 27OMS – summaryExample: Air Traffic Control SystemAir Traffic ControlExample – Air Traffic Control SystemPrinciples of User-Centered DesignCSCI 4800/6800Feb. 1, 2006What is design? Finding the right components of a physical structureA goal-directed problem-solving activitySimulating what we want to make or do before we make or do it – as many times as may be necessary to feel confident in the final resultEngineering design: “the use of scientific principles, technical information and imagination in the definiton of a mechanical structure, machine or system to perform pre-specified functions with the maximum efficiency and economy.ApproachesFormal specificationsCustom crafted / creativeUser-Centered DesignPrinciples–Make user issues central in the design process–Carry out early testing and evaluation with users–Design iterativelyMethods for UCDSoft Systems Methodology (SSM)Open Systems Task Analysis (OSTA)MultiviewStar Life CycleSoft Systems MethodologyFocuses on planningApproach developed by Checkland, Schloes ’81, ’91Emphasis : understand the problem and its situationSSMStages in SSMStages 1 and 2 – obtain “rich expression” of the problem: meetings with stakeholdersStage 3 – obtain precise definition of the systemStage 4 – produce conceptual models: abstract representation, “root definition”SSM, “root definition”•C - Clients (people who will benefit/suffer) •A - Actors (who is involved with system) •T - Transformation (purpose) •W - Weltanschauung/World View (perspective from which root definition is formulated) •O - Owners (who has commissioned system) •E - EnvironmentSSMStage 5 – compare “root definition” of stage 4 with “rich expression” of stage 2; iterate until gaps are filledStage 6 – identify changes Stage 7 – recommend an actionSSMBenefits for HCI engineering:–Identifies people, constraints, view of system–Develops conceptual modelsCooperative DesignParticipative design – users participate in design processSociotechnical design – considers both social and technical alternatives/solutions to/ aspects of problemsOSTA – Open Systems Task Analysis (Eason, Harker ’89)OSTAOSTASpecified together:–Technical requirementsSystem structure, functionality–Social system requirementsUsability, acceptabilityGoal:–Provide method for understanding what occurs when computer system is introduced into a working environmentOSTA – Systems Analysis (top)1. Primary task stated (goals of group of workers identified) 2. Task inputs identified - usually come from outside the system - character of inputs may vary & affect way system behaves 3. External environment - including physical environment, economic, political conditions, demand for task output 4. Transformation processes described typically - object/action flowchart of objects to be transformed & actions neccessary to transform them with annotationsOSTA – technical and social5. Social system analyzed •Roles of people in relation to one another •Characteristics & qualities of users of new system 6. Technical system analyzed - how will new system be integrated with others systems & what remains of the old system? 7. Performance satisfaction – for social system under new technical systems8. Requirements for new technical system, based on the task analysis•Functionality, usability, acceptabilityProblems:Need expert to guide the design processAbility to integrate with other design processes/methodsNeed “right” organizational and political climateCost-effective???MultiviewCombines sociotechnical and soft-systems approachesStage 1: create PTM (primary task model) – similar to “root def”Stage 2: conceptual modeling of info flows/ structure, produce FM (functional model), ER model, dataflow modelsStage 3: design people tasks (PT), role sets (RS), and computer task requirements (CTR)Stage 4: design the HCIStage 5: technical designMultiviewMultiviewProvides more direction for system designersStar Life CycleNo prescribed ordering of activitiesBased on actual design practive of HCI designersEmphasis on prototyping and evaluationRapid prototyping, incremental developmentThe Star Life CycleStar Life CycleConceptual design – what is required? What should system do? What data is required? What will users need to know?Physical design (formal design) : how to achieve the conceptual design …Methods for UCDExample: Olympic Messaging Service (1984 Los Angeles Olympic Games) Kiosks at which athletes could send & receive voice messages among themselvesOr people from around the world could send messages in to athletes & officialTwelve languages (no translation)OMS - ProcessPaper scenarios of user interface prepared –Comments from designers, management, prospective users –Some functions altered, others dropped Brief user guides prepared, tested, developed iteratively (~200 iteratives) –Simulations constructed & evaluated; help messages designed –Simulations tested with usersOMS - ProcessNeeded to add undo/backup button Visit to village site, demos & interviews with ex-olympians & others involved Prototype developed & tested –"Hallway" method to collect info on height & layout of prototype kiosk –"Try-to-destroy-it" tests of robustness (CS students)OMS – summary Focus on users & tasks early in design process, including user guides, help, & ensuring that user's cognitive, social, & attitudinal characteristics are understood & accomodated Measure reactions by using prototype manuals, interface, & other simulations of the system Design iteratively All usability factors must evolve together and be under the responsibility of one control groupExample: Air Traffic Control SystemOriginal system –Variety of info needed, each from own source - some on desk, some on ceiling, some not in line of sight –Dials –Closed Circuit TV –Temporary