Chapter 2

Question 1

What is a model?

Answer 1

A model is a simplified description of an entity or process

Question 2

How are models used?

Answer 2

models are used to help understand a complex system, and by including only the most relevant details and ignoring the less relevant details, engineers can solve the problem at hand.

Question 3

Give an example of a model being used as well as the information that might or might not be relevant.

Answer 3

When modelling an air traffic control system, the size of the wheels and the type of rubber used in the tires of the planes is not relevant, so this information is omitted, even though it is contained in the real system. However, the number of passengers that a plane can carry may be relevant, as it has an impact on the turnaround time of the aircraft.

Question 4

What is a process?

Answer 4

A process is a set of ordered activities, containing inputs, outputs, constraints, and resources, enacted for the purpose of achieving a specified goal.

Question 5

What are examples of inputs that a process may contain?

Answer 5

requirements from the customer

Question 6

What are examples of outputs that a process may contain?

Answer 6

1. the software requirements specification
2. the software itself
3. user manuals

Question 7

What are examples of constraints that a process may contain?

Answer 7

the particular architecture on which the software must run

Question 8

What are examples of resources that a process may contain?

Answer 8

the staff

Question 9

Is requirements engineering a process?

Answer 9

Yes

Question 10

What is the goal of the requirements engineering process?

Answer 10

to produce a quality software requirements specification artifact that correctly captures the user requirements.

Question 11

What activities do most process models for requirements engineering have?

Answer 11

1. elicitation
2. analysis and modelling
3. specification
4. validation

Question 12

Define elicitation as an activity of the requirements engineering process

Answer 12

determining the requirements of the system, typically via research and communicating with the clients;

Question 13

Define analysis and modelling as an activity of the requirements engineering process

Answer 13

break the problem up into smaller problems that are easier to understand and solve, and model the problem using this break-down;

Question 14

Define specification as an activity of the requirements engineering process

Answer 14

record or document the requirements; and

Question 15

Define validation as an activity of the requirements engineering process

Answer 15

determine whether the specified requirements are correct, complete, and consistent.

Question 16

What is an issue with the model of the ideal process? (diagram 1)

Answer 16

It abstracts away from the details that are not important for understanding how to approach requirements engineering.
It is almost worthless, because it offers us little insight as to how to achieve our goal.

Question 17

Is the actual process like the ideal model?

Answer 17

No. At any point in the process, we often return to any other point.
For example:
1. It is not uncommon when specifying the requirements to also be doing analysis, or
2. When validating the requirements, to discover a problem requirement that needs to be re-specified.

Question 18

How are goals and the processes that achieve them structured in a software project?

Answer 18

In a software project, both the goals and the processes that achieve them are hierarchical. Some goals are general, while others are specific.

Question 19

Define software life cycle model

Answer 19

A software life cycle model describes the life cycle of a software project, from conception through to maintenance. It provides a structured blueprint for how a software project should progress.

Question 20

What is the goal of a software life cycle model?

Answer 20

to construct and deliver a quality software product.

Question 21

What helps us decide which software models are good for certain projects?

Answer 21

experience and empirical evidence

Question 22

Explain how the waterfall model works

Answer 22

It encourages engineers to build the system top-down, progressing onto the new phase of development only after the previous phase is complete. That is, only once the requirements have been complete elicited, specified, and validated, does one progress with design. It gets its name from the fact that the phases cascade like a waterfall.

Question 23

What are the stages of the waterfall method?

Answer 23

1. Requirements
2. Design
3. Implementation
4. Testing
5. Maintenance

Question 24

How do you progress from one stage to another in the waterfall method?

Answer 24

1. Requirements
2. Design
3. Implementation
   <code></code>
4. Testing
5. Maintenance</code>

Question 25

What are the downfalls of the waterfall method?

Answer 25

The system testers do not commence testing until after the implementation is complete. However, this is too restrictive: system testers can start designing test cases and test scenarios when the requirements are being finalised.

Question 26

What are the benefits of testing early in project development?

Answer 26

• allows testing to be commenced in parallel, saving time. - allows test engineers to often detect incorrect, incomplete, and inconsistent requirements early in the development process.

There is a rule of thumb that says: “If you cannot write a test for a requirement, then that requirement cannot be implemented”. Therefore, it is advantageous to start test case design during requirements engineering.

Question 27

How does the v-model attempt to overcome the pitfalls if the waterfall method?

Answer 27

By performing the various levels of testing in parallel with the artifacts against which the testing occurs.

Question 28

What are the benefits of testing as you go with the v-model?

Answer 28

test engineers can find defects in the requirements before the design is performed, and before the team begin implementation.
If a defect is only found during implementation, the design must be re-considered, which is more costly than correcting only the requirement itself.

Question 29

Define project management

Answer 29

The application of skill or care in the manipulation, use, treatment, or control of a collaborative enterprise that is carefully planned to achieve a particular aim.
Project management is about being careful in the way that we run our projects, so that they achieve their aims.

Question 30

How are projects managed in software engineering?

Answer 30

by monitoring and controlling.

Question 31

what do we monitor in a project and why?

Answer 31

We monitor the people and resources in the project so we know what is happening and when, so that we can make timely and informed decisions about the project.

Question 32

How do we control the project?

Answer 32

By implementing the timely and informed decisions we make

Question 33

How does the feedback loop between monitoring and controlling the project work?

Answer 33

We must be constantly monitoring the project to learn what is happening, making decisions based on that monitoring, controlling the project by implementing those decisions, and the monitoring the project to see how the implementation is going.
monitor = decide; control
control = implement decisions; monitor

Question 34

Why is monitoring and controlling a project difficult?

Answer 34

Human beings - get sick, slack off, quit, make mistakes. So a PMP may not always go as planned.