1. COMP1007 Introduction to Requirements Analysis © Copyright De Montfort University 2002 All Rights Reserved COMP1007 Introduction to Requirements Analysis Human Computer Interaction

2. COMP1007 Introduction to Requirements Analysis © Copyright De Montfort University 2002 All Rights Reserved Learning Objectives v Define HCI v Explain why we consider HCI within Requirements Analysis v Introduce the main metaphors used in HCI design

3. COMP1007 Introduction to Requirements Analysis © Copyright De Montfort University 2002 All Rights Reserved What is HCI? v Interaction between computer system and users v Popular short-hand for: –The activity of designing a User Interface (UI) –The principles of good design for a UI v People often say “good HCI” when they really mean “good HCI design ”

4. COMP1007 Introduction to Requirements Analysis © Copyright De Montfort University 2002 All Rights Reserved What is HCI? v HCI draws on: –Computer Science –Cognitive and Perceptual Psychology –Ergonomics –Graphic and Communication Design

5. COMP1007 Introduction to Requirements Analysis © Copyright De Montfort University 2002 All Rights Reserved Where Does HIC Fit in the System Architecture? v HCI is implemented in the presentation layer of an application: Ferret Database Ferret Domain reception Sub-system reception Sub-system rehoming Sub-system rehoming HCI Sub-system Application layer Presentation layer Domain layer Database layer

6. COMP1007 Introduction to Requirements Analysis © Copyright De Montfort University 2002 All Rights Reserved Locating HCI in the traditional Life Cycle v Traditionally seen as part of design phase v E.g. Hoffer et al puts HCI in Logical Design: Analysis Adapted from Hoffer et al, 1998 Logical Design Physical Design Forms and Reports Dialogues and Interfaces Files and Databases

7. COMP1007 Introduction to Requirements Analysis © Copyright De Montfort University 2002 All Rights Reserved Locating HCI in the RUP v UI prototypes are an important tool for: –Analysing the problem –Understanding stakeholder needs –Contribute to detailing the Use Cases

8. COMP1007 Introduction to Requirements Analysis © Copyright De Montfort University 2002 All Rights Reserved Why Consider HCI now? v Reasons to include in requirements analysis: –capture usability requirements –ease of learning –environmental factors

9. COMP1007 Introduction to Requirements Analysis © Copyright De Montfort University 2002 All Rights Reserved Why Consider HCI now? v Reasons to include in requirements analysis: –Importance of interface requirements for interactive systems –Prototyping presents UI to users much earlier in life cycle –Even prototypes must be adequately designed!

10. COMP1007 Introduction to Requirements Analysis © Copyright De Montfort University 2002 All Rights Reserved Problems with Considering HCI now v Don’t get too attached to prototypes – not necessarily the final UI v Remember that prototype design features (e.g. data content and structure)  analysis features

11. COMP1007 Introduction to Requirements Analysis © Copyright De Montfort University 2002 All Rights Reserved Two Main Metaphors v Understanding of how HCI works best is based on two main metaphors: As if user and computer “talk” to each other v Dialogue v Direct Manipulation As if user “handles” objects on screen – e.g. using mouse to point, click, drag, etc) v In practice, often use both together

12. COMP1007 Introduction to Requirements Analysis © Copyright De Montfort University 2002 All Rights Reserved The Dialogue Metaphor v 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. COMP1007 Introduction to Requirements Analysis © Copyright De Montfort University 2002 All Rights Reserved Direct Manipulation Metaphor v Creates impression that user physically handles objects on screen v Reflected in windowing systems jargon v You can: drag and drop an icon shrink or expand a window push a button pull down a menu

14. COMP1007 Introduction to Requirements Analysis © Copyright De Montfort University 2002 All Rights Reserved Direct Manipulation v Owes much to spread of event-driven programming v Graphical objects displayed on screen v System responds to events v Most events are result of user actions v UI design more complicated than for straightforward dialogue style v (because interaction sequence is less predictable)

15. COMP1007 Introduction to Requirements Analysis © Copyright De Montfort University 2002 All Rights Reserved Principles of Good Dialogue v Whatever the underlying metaphor, good UI design includes: –Consistency –Appropriate user support –Adequate system feedback –Minimal user input v Style guides (e.g. from Microsoft) show how best to implement these principles

16. COMP1007 Introduction to Requirements Analysis © Copyright De Montfort University 2002 All Rights Reserved Summary v Defined HCI v Explained why we consider HCI within Requirements Analysis v Introduced the main metaphors used in UI design

17. COMP1007 Introduction to Requirements Analysis © Copyright De Montfort University 2002 All Rights Reserved References v Maciaszek (2001), Requirements analysis & system design, Addison Wesley, (Ch 7) v Bennett, S., McRobb, S. & Farmer, R. (1999) “Object- Oriented Systems Analysis and Design using UML”, McGraw-Hill, Maidenhead. (Ch 12 & 15) v Jacobson, I., Booch, G. and Rumbaugh, J. (1999), The Unified Software Development Process, Addison Wesley, Reading Mass. (Ch 7) v Hoffer, J. A., George, J. F. and Valaich, J. S. (1998), Modern Systems Analysis & Design, Addison Wesley Longman, Reading Mass. (Ch 15)