Software Engineering Chapter 2

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Questions and Answers

What is the main characteristic of the waterfall model?

The system is assembled from existing components.

Separate and distinct phases of specification and development. (correct)

Elements from other process models are incorporated.

Specification, development, and validation are interleaved.

What is an advantage of the waterfall model?

It has inherent risk management.

It is suitable for large projects with a long-time development.

It is difficult to follow the sequential steps.

It is simple, widely known, easy to understand and use. (correct)

What is a disadvantage of the waterfall model?

It is widely known and easy to understand.

It is suitable for large projects with a long-time development.

It is hard to follow the sequential steps. (correct)

It has inherent risk management.

Which of the following process models is assembled from existing components?

Reuse-oriented software engineering Signup and view all the answers

Which of the following is not a characteristic of the waterfall model?

Specification, development, and validation are interleaved. Signup and view all the answers

What happens in the waterfall model when a serious error is discovered?

Software is delivered late, delaying the discovery of serious errors. Signup and view all the answers

What is a major challenge in software engineering?

Incorporating further software changes Signup and view all the answers

What is the main focus of reuse-oriented software engineering?

Integrating existing reusable components Signup and view all the answers

What is an advantage of reuse-oriented software engineering?

Faster delivery of software systems Signup and view all the answers

What is a disadvantage of reuse-oriented software engineering?

Compromises in requirements Signup and view all the answers

When is reuse-oriented software engineering applicable?

When there is a pool of existing components Signup and view all the answers

What is the goal of software process activities?

To specify, design, implement, and test software systems Signup and view all the answers

What are software process activities?

Inter-leaved sequences of technical, collaborative, and managerial activities Signup and view all the answers

What does reuse-oriented software engineering make intensive use of?

Existing reusable components Signup and view all the answers

What is an advantage of incremental delivery?

It delivers customer value with each increment Signup and view all the answers

What is a problem with incremental delivery?

It can be hard to identify common facilities needed by all increments Signup and view all the answers

What is a characteristic of Boehm's spiral model?

It represents the process as a spiral rather than a sequence of activities Signup and view all the answers

What is an advantage of incremental delivery in terms of risk?

It reduces the risk of overall project failure Signup and view all the answers

What is a challenge of using incremental delivery in certain organizations?

It is not compatible with the procurement model of many organizations Signup and view all the answers

What is a key aspect of Boehm's spiral model in terms of risks?

Risks are explicitly assessed and resolved throughout the process Signup and view all the answers

What is the primary focus of the objective setting sector in the spiral model?

Setting specific objectives for the phase Signup and view all the answers

What is the purpose of the risk analysis sector in the spiral model?

To identify and resolve risks Signup and view all the answers

In which sector of the spiral model is the product design developed?

Design Signup and view all the answers

What is the outcome of the review sector in the spiral model?

A plan for the next phase Signup and view all the answers

What is the primary purpose of the simulations, models, and benchmarks in the spiral model?

To validate the software requirements Signup and view all the answers

What is the focus of the development sector in the spiral model?

Developing and verifying the next-level product Signup and view all the answers

What is the outcome of the operational prototype sector in the spiral model?

A working operational prototype Signup and view all the answers

What is the purpose of the integration and test plan sector in the spiral model?

To plan the integration and testing of the product Signup and view all the answers

What is one of the primary benefits of the incremental development approach?

It allows for more rapid delivery and deployment of useful software to the customer. Signup and view all the answers

What is a common problem with the incremental development approach?

The system structure tends to degrade as new increments are added. Signup and view all the answers

In the incremental development approach, what is the purpose of initial specification?

To provide an initial outline description of the software. Signup and view all the answers

What is a benefit of the incremental development approach in terms of customer requirements?

It reduces the cost of accommodating changing customer requirements. Signup and view all the answers

What is a challenge that managers face when using the incremental development approach?

They need to produce regular deliverables to measure progress. Signup and view all the answers

What is a benefit of the incremental development approach in terms of customer feedback?

It allows customers to comment on demonstrations of the software. Signup and view all the answers

What is a risk associated with large and long-term development projects?

High risk due to the complexity of the project. Signup and view all the answers

What is the purpose of the intermediate versions in the incremental development approach?

To develop and test each increment of the software. Signup and view all the answers

Study Notes

Software Process Models

There are several software process models, including the waterfall model, incremental development, and reuse-oriented software engineering.
In practice, most large systems are developed using a process that incorporates elements from all of these models.

Waterfall Model

The waterfall model is a plan-driven model with separate and distinct phases of specification and development.
Advantages:
Easy to understand and use
Works well on small projects with a short-time development
In some respects, it is the "common sense" approach
Disadvantages:
Hard to follow the sequential step
Unrealistic to expect accurate requirements early in a project
No inherent risk management and expensive to change decisions
Software is delivered late, delays discovery of serious errors
High risk for large and long-term development projects

Incremental Development

Incremental development interleaves specification, development, and validation.
Benefits:
Reduces the cost of accommodating changing customer requirements
Reduces the amount of analysis and documentation that has to be redone
Easier to get customer feedback on the development work
More rapid delivery and deployment of useful software to the customer
Problems:
The process is not visible
System structure tends to degrade as new increments are added
Incorporating further software changes becomes increasingly difficult and costly

Reuse-Oriented Software Engineering

Based on systematic reuse where systems are integrated from existing components or COTS (Commercial-off-the-shelf) systems.
Process stages:
Component analysis
Requirements modification
System design with reuse
Development and integration
Main characteristics:
Makes intensive use of existing reusable components
Focus is on integrating the components rather than on creating them from scratch
Advantages:
Reduces considerably the software to be developed "in-house"
Allows faster delivery
In principle, more reliable systems, due to using previously tested components
Disadvantages:
Compromises in requirements are needed
Less control over the system's evolution

Process Activities

Real software processes are inter-leaved sequences of technical, collaborative, and managerial activities.
The overall goal is to specify, design, implement, and test a software system.

Incremental Delivery

Advantages:
Customer value can be delivered with each increment
Early increments act as a prototype to help elicit requirements for later increments
Lower risk of overall project failure
The highest priority system services tend to receive the most testing
Problems:
Most systems require a set of basic facilities that are used by different parts of the system
The essence of iterative processes is that the specification is developed in conjunction with the software

Boehm's Spiral Model

Process is represented as a spiral rather than as a sequence of activities with backtracking.
Each loop in the spiral represents a phase in the process.
No fixed phases such as specification or design - loops in the spiral are chosen depending on what is required.
Risks are explicitly assessed and resolved throughout the process.

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Description

This quiz covers the Boehm's spiral model of software process, determining objectives, evaluating alternatives, and identifying and resolving risks in software development.