1、Ian Sommerville 2000 Software Engineering, 6th edition. Chapter 8 Slide 1Software Prototyping原型法l Rapid software development to validate requirements快速原型开发以验证需求Ian Sommerville 2000 Software Engineering, 6th edition. Chapter 8 Slide 2Objectives教学目的l To describe the use of prototypes in different type
2、s of development projectl To discuss evolutionary and throw-away prototypingl To explain the need for user interface prototypingIan Sommerville 2000 Software Engineering, 6th edition. Chapter 8 Slide 3Topics covered主要内容l Prototyping in the software processl Prototyping techniquesl User interface pro
3、totypingIan Sommerville 2000 Software Engineering, 6th edition. Chapter 8 Slide 4System prototyping系统原型l Prototyping is the rapid development of a systeml In the past, the developed system was normally thought of as inferior in some way to the required system so further development was requiredl Now
4、, the boundary between prototyping and normal system development is blurred and many systems are developed using an evolutionary approachIan Sommerville 2000 Software Engineering, 6th edition. Chapter 8 Slide 5Uses of system prototypes系统原型的使用l The principal use is to help customers and developers un
5、derstand the requirements for the system帮助用户和开发者理解需求l Prototyping can be considered as a risk reduction activity which reduces requirements risks降低风险Ian Sommerville 2000 Software Engineering, 6th edition. Chapter 8 Slide 6Prototyping benefits原型法的好处l Misunderstandings between software users and devel
6、opers are exposedl Missing services may be detected and confusing services may be identifiedl A working system is available early in the processl The prototype may serve as a basis for deriving a system specificationl The system can support user training and system testingIan Sommerville 2000 Softwa
7、re Engineering, 6th edition. Chapter 8 Slide 7Prototyping benefits原型法的好处l Improved system usabilityl Closer match to the system neededl Improved design qualityl Improved maintainabilityl Reduced overall development effortIan Sommerville 2000 Software Engineering, 6th edition. Chapter 8 Slide 8Protot
8、yping in the software process快速原型的类型1. Evolutionary prototyping 进化式 An approach to system development where an initial prototype is produced and refined through a number of stages to the final system2. Throw-away prototyping 抛弃式 A prototype which is usually a practical implementation of the system i
9、s produced to help discover requirements problems and then discarded. The system is then developed using some other development processIan Sommerville 2000 Software Engineering, 6th edition. Chapter 8 Slide 9Prototyping objectives原型法目标l The objective of evolutionary prototyping is to deliver a worki
10、ng system to end-users. The development starts with those requirements which are best understood.l The objective of throw-away prototyping is to validate or derive the system requirements. The prototyping process starts with those requirements which are poorly understoodIan Sommerville 2000 Software
11、 Engineering, 6th edition. Chapter 8 Slide 10Evolutionary prototyping进化型l Must be used for systems where the specification cannot be developed in advance e.g. AI systems and user interface systemsl Based on techniques which allow rapid system iterationsl Verification is impossible as there is no specification. Validation means demonstrating the adequacy of the system
