Design Space Analysis and Prototyping

1
Design Space Analysisand Prototyping
2
Agenda

• Questions
• Design Space Analysis
• Prototyping
• Scenarios
• Return Project Part 1

3
Design Rationale

• Information that explains why a computer system
  is the way it is
• Communication mechanism
• Transfer accumulated knowledge
• Forces more deliberate, careful decisions

4
Approaches to Design Rationale

• Process oriented
• Captures as design progresses
• IBIS - Issues, Positions, Arguments
• Design Space Analysis
• Post Hoc structuring of alternatives space
• QOC Questions, Options, Criteria
• Psychological or Claims Analysis
• General, broad aspect of system that has an
  important consequence for user of system
• Create scenarios of use

5
Why Prototype?

• Failure of waterfall
• Fail fast
• Explore design space

6
Prototyping Iterative Design

• Design is hard to get right initially
• chicken egg problem
• Build partial systems, evaluate, repeat
• What to prototype???

7
Dimensions of Prototypes

• Representation
• sketch, scenarios, comp. system, video
• Scope
• vertical slice (details)
• horizontal slice (story)

8
Dimensions of Prototypes contd

• Low vs. High fidelity
• Incremental vs. Evolutionary
• Chauffeured vs. Wizard of Oz

9
On Executability

• Attaining authenticity of interaction is the goal

10
Prototyping Issues

• Throw-away or incremental?
• decide and stick to it
• Design inertia

11
Prototyping Issues (contd)

• Non-functional features
• some are impossible with quick prototype
• performance, aesthetics, social
• Understand reasons behind usability problems
  observed

12
Techniques

• Storyboards, Sketches
• Models
• Scenarios
• Limited functionality
• Wizard of Oz
• High-level programming support

13
Scenarios

• Fictional stories with characters, products,
  events and environments.
• Narratives, sketches, videos, simulations

14
Why Use Scenarios

• future vs. present
• holistic vs. piecemeal
• reveal different perspectives
• engaging (even fun)

15
Why Use Scenarios (contd)

• Alternate visions - compare
• Share with different audiences
• Explore errors and mistakes

16
What to Include

• Building holistic view
• environment, people, interface, other objects and
  activities
• logical, multi-sensory and emotional paths
• Detailed ideas expressed simultaneously

17
Project Part 1 Recap

• Grading criteria (out of 100)
• Poster 5
• Description 10
• User Profile 20
• Task Analysis 25
• Existing system 20
• Usability 10
• Reflections/Process 10

18
Points to remember

• Know your user
• Show evidence of interviews/surveys
• Surprises are good
• Be methodical and not haphazard
• Task analysis
• Understanding of activities and artifacts used
• Review with end users
• Criteria made specific to project

19
Points to remember

• Guard against bias
• technological solution of your own
• opinions about users activities/problems

20
Project Part 2

• Themes
• exploring design space
• solidifying requirements
• Look to template
• Design Meetings, includeDesign Description,
  Rationale, Illustration, Scenario, Assessment
• More Thursday on Project Part 2 Cognitive Models