Designing Interactive Systems: Achieving User Goals and Constraints

1. Human Computer InteractionLecture 10Interaction Paradigms

2. What is design? achieving goals within constraints • goals - purpose • who is it for, why do they want it • constraints • materials, platforms, money • trade-offs

3. for Human–Computer Interaction understand your materials • understand computers • limitations, capacities, tools, platforms • understand people • psychological, social aspects, human error • and their interaction …

4. To err is human • Accident reports .. • aircrash, industrial accident, hospital mistake • enquiry … blames … ‘human error’ • But … • In fact not human error but human nature • concrete lintel breaks because too much weight • blame ‘lintel error’ ?… no – design error we know how concrete behaves under stress • Human ‘error’ is normal • we know how users behave under stress • so design for it! • Treat the user at least as well as physical materials!

5. scenariostask analysis guidelines principles precisespecification interviews Ethnography (study of cultures) what is there vs. what is wanted dialoguenotations evaluation heuristics architectures documentation help The process of design what iswanted analysis design implement and deploy prototype

6. Requirements • what is there and what is wanted … • Analysis • ordering and understanding • Design • what to do and how to decide • Iteration and prototyping • getting it right … and finding what is really needed! • Implementation and deployment • making it and getting it out there

7. User FocusDesigning systems with focus on user is called User-Centred Design. How to design with focus on users? know your user Personae (character)

8. Know your USER • who are they? • Harder to answer if you are designing a generic software like word processor • probably not like you! • You assume your own interests and abilities • talk to them • Structured interviews, open-ended discussions • Bringing potential users fully into the design process - Participatory design

9. know your user • watch them • Talking with people might not be enough • Think about walking • Solution: watch and observe them either informally or involving them • Observations tell you what they do, they will tell you why

10. know your user • use your imagination • Observing users can be costly … imagine their experiences

11. Persona • Picture of an imaginary person who represents your core user group • description of an ‘example’ user • not necessarily a real person • use as substitute user • what would Betty (as a Warehouse manager) think

12. Scenarios stories for design use and reuse

13. scenarios • stories for design or stories of interaction • Example of a short scenerio: • User intends to press the “save” button, but accidentally presses the “quit” button, so looses his work • communicate with others (Designers, users) • validate other models • understand dynamics (Behaviour of system not only screen shot) • linearity • time is linear - our lives are linear

14. Navigation Design Local structure – single screen(control) Global structure – whole(system) site

15. Local Structure From one screen looking out

16. Four golden rules • knowing where you are • knowing what you can do • knowing where you are going • or what will happen • knowing where you’ve been • or what you’ve done

17. Where you are – breadcrumbs • shows path through web site hierarchy • -Category, subcategory , this page

18. Design Focus- modes • lock to prevent accidental use … • remove lock - ‘c’ + ‘yes’ to confirm • frequent practiced action • if lock forgotten • in pocket ‘yes’ gets pressed • goes to phone book • in phone book … ‘c’ – delete entry ‘yes’ – confirm… oops !

19. Global Structure between screens within the application

20. the system info and help management messages add user remove user Hierarchical Diagrams

21. main screen remove user confirm add user Network Diagrams show different paths through system

22. Levels of Interaction • Widget choice • Menus etc. • Form Elements, tag, links • Buttons, dials, lights • Screen design, Page design • Application navigation, Site Structure • Environment • other apps, O/S ,Web browser, The real world