SA550 Analysis and Design Modeling

Question 1

1. What two complementary processes are used in modeling for software development?

Answer 1

Abstraction and refinement.

SA550 slide 6

Question 2

2. What is meant by a primitive process in a DFD?

Answer 2

A primitive process is one that is not further broken down into a lower level diagram. We write mini-specs for primitive processes.

SA550 slide 13

Question 3

3. What is the “rule of seven” for DFDs?

Answer 3

The “rule of seven” is a guideline that says we strive to keep the number of processes shown in any one given diagram to a maximum of seven.

SA550 slide 14

Question 4

4. What is the purpose of the vertical view of a process decomposition diagram?

Answer 4

The vertical view identifies the major functional sub-processes of an overall process.

SA550 slide 19

Question 5

5. What is meant by a heuristic method in the context of converting a DFD into a process decomposition diagram?

Answer 5

A heuristic method is a set of guidelines of rules of thumb, as opposed to an actual algorithm.

SA550 slide 25

Question 6

6. What is the first step in converting a DFD to a process decomposition diagram?

Answer 6

The first step in converting a DFD to a process decomposition diagram is to identify the area of central processing in the DFD.

SA550 slide26

Question 7

7. How is the control information in the DFD represented in a process decomposition diagram?

Answer 7

Actually there should be little of no control information in the DFD which documents the “what” and not the “how”. You must add control and sequencing information that reflect the way the processes interact.

SA550 slide 29

Question 8

8. What is the purpose of an activity diagram or workflow diagram?

Answer 8

An activity diagram (also called a workflow diagram) shows a high-level view of a business process, indicating steps, inputs and outputs.

SA550 slide 41

Question 9

9. What is a high-level description of a system architecture?

Answer 9

At the high level it describes the overall structure and design of the system.

SA550 slide 50

Question 10

10. Name the six major BCBSSC design concepts.

Answer 10

The six major design concepts at BCBSSC are:

1. modularity
2. loose coupling
3. reuse
4. flexibility,
5. encapsulation
6. balancing and reconciliation

SA550 slide 53

Question 11

11. What is coupling?

Answer 11

Coupling is a measure of the strength of the relationship or degree of interdependence between program modules or components.

SA550 slides 55, 73 and 74

Question 12

12. What is cohesion?

Answer 12

Cohesion is a measure of the focus or functional coherence of a module.

SA550 slides 55, 81 and 82

Question 13

13. What is meant by the term data hiding?

Answer 13

Data hiding (also called encapsulation) has to do with sending only the information needed to a module when it is called, providing a form of logical independence.

SA550 slides 59, 71 and 72

Question 14

14. What are the four levels of design in software development?

Answer 14

The four levels of design are”

1. data design
2. architectural design
3. interface design
4. component design

SA550 slide 67

Question 15

15. What is the span of control principle?

Answer 15

Span of control refers to the number of modules called by another module. The objective is to keep this reasonably small.

SA550 slide 72

Question 16

16. Which is preferred: data coupling or stamp coupling?

Answer 16

Data coupling is the idea coupling. Stamp coupling is acceptable, but less desirable.

SA550 slides 77 and 78

Question 17

17. Is sequential cohesion acceptable?

Answer 17

Generally sequential cohesion is acceptable provided the tasks that are well-focused, although functional cohesion is preferable. Sequential modules can be factored into functionally cohesive modules when this is deemed appropriate.

SA550 slides 83 - 88

Question 18

18. What is meant by black box design?

Answer 18

In black box design, the focus is on the high-level functionality of the module and its inputs and outputs. The details of the implementation of the functionality are left for the later component design.

SA550 slides 89 and 90

Question 19

19. How would you describe Structured English?

Answer 19

Structured English is not a formal language, but rather a set of guidelines for writing more precise and less ambiguous English specifications.

SA550 slide 94

Question 20

20. What are the uses for decision trees and tables?

Answer 20

Decision trees and decision tables are used to graphically represent complex decision algorithms.

SA550 slides 89 -103

Question 21

Define abstraction.

Answer 21

Extract and model main ideas from details.

Question 22

Define refinement.

Answer 22

Reinstate and organize details in hierarchy of levels as needed

Question 23

Define modularity.

Answer 23

Manage the complexity in the refinement of the model.