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Requirements Analysis 8. 1 Storyboarding - 2005b508.ppt
© Copyright De Montfort University 2000All Rights Reserved
INFO2005Requirements Analysis
Human Computer Interaction
Department of Information Systems
Requirements Analysis 8. 2 Storyboarding - 2005b508.ppt
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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
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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”
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What is HCI?
HCI draws on:
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Where Does HIC Fit in the System Architecture?
HCI is implemented in the presentation layer of an application:
Campaign Database
Campaign Domain
Advert
Sub-system
Advert HCI
Sub-system
Campaign Costs
Sub-system
Campaign Costs
HCI Sub-system
Application layer
Presentation layer
Domain layer
Database layerAdapted from Bennett et al,
1999
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Locating HCI in the traditional Life Cycle
Traditionally seen as part of design phase E.g. Hoffer et al puts HCI in Logical Design:
Analysis
Adapted from Hoffer et al, 1998
Logical Design
Physical Design
Forms and ReportsDialogues and
InterfacesFiles and Databases
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Locating HCI in the RUP
In RUP, HCI fits in many places
E.g. in the Requirements Analysis Workflow:
Requirements Analysis 8. 8 Storyboarding - 2005b508.ppt
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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)
Requirements Analysis 8. 9 Storyboarding - 2005b508.ppt
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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!
Requirements Analysis 8. 10 Storyboarding - 2005b508.ppt
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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
Requirements Analysis 8. 11 Storyboarding - 2005b508.ppt
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Two Main Metaphors Understanding of how HCI works best
is based on two main metaphors:
Dialogue
Direct Manipulation
In practice, often use both together
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The Dialogue Metaphor
A dialogue may be a natural translation of a Use Case scenario:
User selects option from menuSystem displays order entry form (date and next order no filled in automatically)User enters Customer CodeSystem displays name and address of customer (to confirm correct number entered)Etc...
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Types of Message in a Dialogue
Input control 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
Adapted from Bennett et al, 1999
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Direct Manipulation Metaphor Creates impression that user
physically handles objects on screen Reflected in windowing systems jargon You can:
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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)
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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
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Approaches to UI Design
Three main categories of approach to UI design:
All three cover requirements gathering, UI design and UI evaluation
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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
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Example Structured Approach This diagram
shows an overview of the STUDIO approach
301 Task
Synthesis
302 Style Guide
STAGE 2
303 Design
Specification
301 Task
Synthesis
304 User
Support
User Support Documentation
Task Hierarchy Diagrams
Task Hierarchy Diagrams Knowledge Representation
Grammars Action List Object List
Interaction Rules
User Interface Style
General User Interface
Decisions
Textual Content of Dialogue
User Interface Specification User Interface Function
Catalogue
STAGE 4
Bennett et al, 1999, adapted from Browne, 1994
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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
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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
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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
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Scenario-Based Approaches Potential disadvantage: a large
amount of textual documentation can be generated
Requires careful management and cross-referencing
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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
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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)