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Principles of User-Centered Design

Principles of User-Centered Design. CSCI 4800/6800 Feb. 1, 2006. What is design? . Finding the right components of a physical structure A goal-directed problem-solving activity

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Principles of User-Centered Design

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  1. Principles of User-Centered Design CSCI 4800/6800 Feb. 1, 2006

  2. What 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.

  3. Approaches • Formal specifications • Custom crafted / creative

  4. User-Centered Design • Principles • Make user issues central in the design process • Carry out early testing and evaluation with users • Design iteratively

  5. Methods for UCD • Soft Systems Methodology (SSM) • Open Systems Task Analysis (OSTA) • Multiview • Star Life Cycle

  6. Soft Systems Methodology • Focuses on planning • Approach developed by Checkland, Schloes ’81, ’91 • Emphasis : understand the problem and its situation

  7. SSM

  8. Stages 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”

  9. 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 - Environment

  10. SSM • 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 action

  11. SSM • Benefits for HCI engineering: • Identifies people, constraints, view of system • Develops conceptual models

  12. Cooperative 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)

  13. OSTA

  14. OSTA • 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 environment

  15. OSTA – Systems Analysis (top) • Primary task stated (goals of group of workers identified) • Task inputs identified - usually come from outside the system - character of inputs may vary & affect way system behaves • External environment - including physical environment, economic, political conditions, demand for task output • Transformation processes described typically - object/action flowchart of objects to be transformed & actions neccessary to transform them with annotations

  16. OSTA – technical and social 5. Social system analyzed • Roles of people in relation to one another • Characteristics & qualities of users of new system • Technical system analyzed - how will new system be integrated with others systems & what remains of the old system? • Performance satisfaction – for social system under new technical systems • Requirements for new technical system, based on the task analysis • Functionality, usability, acceptability

  17. Problems: • Need expert to guide the design process • Ability to integrate with other design processes/methods • Need “right” organizational and political climate • Cost-effective???

  18. 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 design

  19. Multiview

  20. Multiview • Provides more direction for system designers

  21. Star Life Cycle • No prescribed ordering of activities • Based on actual design practive of HCI designers • Emphasis on prototyping and evaluation • Rapid prototyping, incremental development

  22. The Star Life Cycle

  23. Star 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 …

  24. Methods for UCD

  25. Example: 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)

  26. 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 users

  27. OMS - 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)

  28. 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 group

  29. Example: 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 instructions

  30. Air Traffic Control • Desire: Integrated data display system • SAFETY (major concern) • "Upgradeable" • Variety of airports/local requirements • Modified info requirements • Layouts specific to controller & task • More color • Ability to add pages for specific local conditions • Simple editing facilities for updates

  31. Example – Air Traffic Control System • Process: • Evaluate controller’s task • Develop first-cut design • Establish user-systems design group • Concept testing, user feedback • Produce upgraded prototype • Road-show to five airports • Develop systems specification • build and install system • establish new needs

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