INFO2005 Requirements Analysis Human Computer Interaction

1. INFO2005Requirements AnalysisHuman Computer Interaction Department of Information Systems

2. Learning Objectives • Define HCI • Explain why we consider HCI within Requirements Analysis • Introduce the main metaphors used in HCI design • Overview major approaches to HCI design

3. What is HCI? • A sub-discipline of Information Systems • Focuses on interaction between a computer system and its users • Has also become popular short-hand for: • People often say “good HCI” when they really mean “good HCI design”

4. What is HCI? • HCI draws on:

5. Advert HCI Campaign Costs Presentation layer Sub - system HCI Sub - system Advert Campaign Costs Application layer Sub - system Sub - system Domain layer Campaign Domain Database layer Campaign Database Where Does HIC Fit in the System Architecture? • HCI is implemented in the presentation layer of an application: Adapted from Bennett et al, 1999

6. Forms and Reports Dialogues and Interfaces Files and Databases Analysis Physical Design Logical Design Locating HCI in the traditional Life Cycle • Traditionally seen as part of design phase • E.g. Hoffer et al puts HCI in Logical Design: Adapted from Hoffer et al, 1998

7. Locating HCI in the RUP • In RUP, HCI fits in many places • E.g. in the Requirements Analysis Workflow:

8. Locating HCI in the RUP • In RUP, UI prototypes are an important tool for: • The UI designer works closely with the Use Case specifier (may be the same person)

9. Why Consider HCI with Requirements Analysis? • Reasons to include in requirements analysis: • To capture usability requirements, ease of learning, environmental factors • Importance of interface requirements for interactive systems • Prototyping presents UI to users much earlier in life cycle • Even prototypes must be adequately designed!

10. Problems with Considering HCI within Requirements Analysis • Some important drawbacks must be kept in mind: • Don’t get too attached to prototypes – not necessarily the final UI • Remember that prototype design features (e.g. data content and structure) analysis features

11. Two Main Metaphors • Understanding of how HCI works best is based on two main metaphors: • Dialogue • Direct Manipulation • In practice, often use both together

12. The Dialogue Metaphor • A dialogue may be a natural translation of a Use Case scenario: User selects option from menu System displays order entry form (date and next order no filled in automatically) User enters Customer Code System displays name and address of customer (to confirm correct number entered) Etc...

13. control Input User directs way in which dialogue will proceed data Numbers, codes and quantities supplied by user Output prompt Request for user input data Data from application following user request or input status Acknowledgement that something has happened error Processing cannot continue help Additional information to user Types of Message in a Dialogue Adapted from Bennett et al, 1999

14. Direct Manipulation Metaphor • Creates impression that user physically handles objects on screen • Reflected in windowing systems jargon • You can:

15. Direct Manipulation • Owes much to spread of event-driven programming • Graphical objects displayed on screen • System responds to events • Most events are result of user actions • UI design more complicated than for straightforward dialogue style • (because interaction sequence is less predictable)

16. Principles of Good Dialogue • Whatever the underlying metaphor, good UI design includes: • Style guides (e.g. from Microsoft) show how best to implement these principles

17. Approaches to UI Design • Three main categories of approach to UI design: • All three cover requirements gathering, UI design and UI evaluation

18. Structured Approaches • Assume a structured approach to systems development as a whole • UI design and development runs alongside main project lifecycle • Generally provide detailed specification of tasks and steps in UI development • Examples: STUDIO and RESPECT

19. Example Structured Approach • This diagram shows an overview of the STUDIO approach Bennett et al, 1999, adapted from Browne, 1994

20. Ethnographic Approaches • “Ethnography” applies to a range of techniques in sociology / anthropology • A particular philosophy about scientific enquiry • Only by being part of a situation can you truly understand and interpret it • In HCI this means spending time with users immersed in everyday working life

21. Ethnographic Approaches • Users interpret systems subjectively • HCI professional must understand this, not assume they can assess objectively • Only thus can real requirements be understood and documented • Xerox PARC has employed trained ethnographers for many years

22. Scenario-Based Approaches • Scenario-based approach fits naturally with Use Case driven development • Less formal than structured approaches • More organised than ethnographic approaches • Similar to Use Case descriptions • Can show alternative realisations of a use case • Can also include “claims” – justification of design decisions

23. Scenario-Based Approaches • Potential disadvantage: a large amount of textual documentation can be generated • Requires careful management and cross-referencing

24. Summary • Defined HCI • Explained why we consider HCI within Requirements Analysis • Introduced the main metaphors used in UI design • Overviewed 3 main types of approach to UI design

25. References • Bennett, S., McRobb, S. & Farmer, R. (2002) “Object-Oriented Systems Analysis and Design using UML”, McGraw-Hill, Maidenhead. (Ch 14 & 16) • Jacobson, I., Booch, G. and Rumbaugh, J. (1999), The Unified Software Development Process, Addison Wesley, Reading Mass. (Ch 7) • Hoffer, J. A., George, J. F. and Valaich, J. S. (1998), Modern Systems Analysis & Design, Addison Wesley Longman, Reading Mass. (Ch 15)