1. Informatics 121 Software Design I
Lecture 10
Duplication of course material for any commercial purpose without the explicit written permission of the professor is prohibited.

2. Discussion There will be discussion this Friday
Please join your designated discussion

3. Today’s lecture
Design notations
Design studio 2 (continued)

4. Intermezzo: what experts do
Experts repeat activities
Experts explore different perspectives
Experts move among levels of abstraction
Experts rotate among subject pairs

5. Design designer plan maker change in the world other stakeholders
audience
experiences

6. A design artifact
An externalized representation used to further a design project
design problem, design solution, or both
partial or complete
fluid or frozen

7. Example

8. Example

9. Example

10. Example

11. Example

12. Purpose of design artifacts
Design artifacts to think
Design artifacts to talk
Design artifacts to prescribe

13. Thinking design artifact

14. Thinking design artifact

15. Thinking design artifact

16. Talking design artifact

17. Talking design artifact

18. Talking design artifact

19. Prescribing design artifact

20. Prescribing design artifact

21. Prescribing design artifact

22. Abstraction
An abstraction is formed by reducing the information content of a concept or an observable phenomenon, typically to retain only information which is relevant for a particular purpose
choice of what to include
choice of what not to include
Each abstraction makes some information readily available at the expense of obscuring or removing other information

23. Floor plan

24. Verilog

25. Page layout

26. Mechanical engineering diagram

27. Schematic

28. Product sketch

29. Model

30. Design notation
A design notation offers a language for specifying certain aspects of a design artifact
textual and/or graphical vocabulary for specifying individual and composite elements
rules governing how individual elements can be combined into composite elements
implicit and/or explicit semantics for giving meaning
Each design notation is typically suited for a particular domain and a particular purpose
Every design notation invariably introduces abstraction

31. Example notation

32. Example notation

33. Example notation

34. Vocabulary may exist independent of notation

35. Notation or just a vocabulary?

36. Considerations in choosing a design notation
Who is the audience?
What is the objective?
What is the timeframe?

37. Expressiveness versus usability
high
low
expressiveness
usability

38. Cognitive dimensions of notations
Abstraction
types and availability of abstraction mechanisms
Hidden dependencies
important links between entities are not visible
Premature commitment
constraints on the order of doing things
Secondary notation
extra information in means other than formal syntax
Viscosity
resistance to change
Visibility
ability to view components easily
Closeness of mapping
closeness of representation to domain
Consistency
similar semantics are expressed in similar syntactic forms
Diffuseness
verbosity of language
Error-proneness
notation invites mistakes
Hard mental operations
high demand on cognitive resources
Progressive evaluation
work-to-date can be checked at any time
Provisionality
degree of commitment to actions or marks
Role-expressiveness
the purpose of a component is readily inferred

39. Software design
Design artifacts
Design notation

40. Software design artifact

41. Software design artifact

42. Software design artifact

43. Thinking software design artifact

44. Talking software design artifact

45. Prescribing software design artifact

46. Class diagram

47. User interface mock-up
[balsamiq]

48. Entity relationship diagram

49. Sequence diagram

50. Example notation

51. Example notation

52. Example notation

53. Unified Modeling Language
Structure diagram
class diagram
component diagram
package diagram
deployment diagram …
Behavior diagram
activity diagram
use case diagram
sequence diagram
communication diagram

54. Class diagram

55. Sequence diagram

56. Design studio 2
You are to design the educational traffic simulator that is described in the design prompt that we handed out in class today
This will be a multi-week, multi-step effort

57. Design studio 2 (original)
As a team…
…identify the audience and other stakeholders
…identify possible goals, constraints, and assumptions
…apply the feature comparison and mind mapping design methods

58. Design studio 2 (continued)
As a team…
…refine the audience and other stakeholders as needed
…refine possible goals, constraints, and assumptions as needed
…apply the personas and morphological charts design methods (to the interaction design)
…create your final interaction design (as a series of screenshots that detail how it works)
…create your final implementation design (as a UML class diagram detailing the main classes and methods, together with documentation that describes how it works)

59. Design studio 2 (continued)
Grading criteria
your understanding of the design problem
innovativeness, understandability, elegance, and completeness of the design solution
does it do what it is supposed to do
“can we understand what you did, why, and do we believe you made good choices”

60. Design studio 2 (continued)
Due Tuesday November 18, at the beginning of class