南方医科大学：《软件工程》课程教学资源（PPT课件）第7章 面向对象分析

CHAPTER 7-1 HOW INFORMATION SYSTEMS ARE DEVELOPED 如何开发信息系统

Slide 2.1 1/50 CHAPTER 7-1 HOW INFORMATION SYSTEMS ARE DEVELOPED 如何开发信息系统

Chapter Overview Information System Development in Theory理论上的信息系统开发 Winburg Mini Case Study一个小型案例研究 Lessons of the Winburg Mini Case Study这个小型案例研究的教训 Teal Tractors Mini Case Study第二个小型案例研究 Iteration and Incrementation迭代和增量★ Iteration:The Newton-Raphson Algorithm迭代：牛顿拉普森算法 The Winburg Mini Case Study Revisited再次探讨第二个小型案例 Other Aspects of Iteration and Incrementation迭代和增量的其他方面 Managing Iteration and Incrementation管理迭代和增量 Maintenance Revisited再论维护

Slide 2.2 2/50 Chapter Overview Information System Development in Theory 理论上的信息系统开发 Winburg Mini Case Study 一个小型案例研究 Lessons of the Winburg Mini Case Study 这个小型案例研究的教训 Teal Tractors Mini Case Study 第二个小型案例研究 Iteration and Incrementation 迭代和增量★ Iteration: The Newton–Raphson Algorithm 迭代: 牛顿-拉普森算法 The Winburg Mini Case Study Revisited 再次探讨第二个小型案例 Other Aspects of Iteration and Incrementation 迭代和增量的其他方面 Managing Iteration and Incrementation 管理迭代和增量 Maintenance Revisited 再论维护

Information System Development Ideally,an information system is developed Linear Starting from scratch(从头 Requirements 开始) In the real world,it is very Analysis different We make mistakes Design The client's requirements change Implementation Development

Slide 2.3 3/50 Information System Development Ideally, an information system is developed – Linear – Starting from scratch(从头 开始) In the real world, it is very different – We make mistakes – The client’s requirements change

Chapter Overview Information System Development in Theory理论上的信息系统开发 Winburg Mini Case Study一个小型案例研究 Lessons of the Winburg Mini Case Study这个小型案例研究的教训 Teal Tractors Mini Case Study第二个小型案例研究 Iteration and Incrementation迭代和增量 Iteration:The Newton-Raphson Algorithm迭代：牛顿拉普森算法 The Winburg Mini Case Study Revisited再次探讨第二个小型案例 Other Aspects of Iteration and Incrementation迭代和增量的其他方面 Managing Iteration and Incrementation管理迭代和增量 Maintenance Revisited再论维护

Slide 2.4 4/50 Chapter Overview Information System Development in Theory 理论上的信息系统开发 Winburg Mini Case Study 一个小型案例研究 Lessons of the Winburg Mini Case Study 这个小型案例研究的教训 Teal Tractors Mini Case Study 第二个小型案例研究 Iteration and Incrementation 迭代和增量 Iteration: The Newton–Raphson Algorithm 迭代: 牛顿-拉普森算法 The Winburg Mini Case Study Revisited 再次探讨第二个小型案例 Other Aspects of Iteration and Incrementation 迭代和增量的其他方面 Managing Iteration and Incrementation 管理迭代和增量 Maintenance Revisited 再论维护

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Slide 2.5 5/50

现在要开发一种自动识 别纸币的软件，既要防止 伪钞，速度又要快。 Winburg市长 You can trust me!

Slide 2.6 6/50 You can trust me! 为了缓解交通拥挤状况， 请全体市民“泊车换 乘”(park and ride)，换 乘只花一块钱。 现在要开发一种自动识 别纸币的软件，既要防止 伪钞，速度又要快。 Winburg市长

Winburg Mini Case Study Episode(情节)1：The1 st version is implemented Episode 2:A mistake is found - 10s-too slow-implementation fault:double Changes double to float Episode 3:Revise -4.5s-still slow-poor image recognition algorithm A faster algorithm is used-1s Episode 4:A new design is adopted -Development is complete Episode 5:A few years later Hardware changed,software has to be changed

Slide 2.7 7/50 Winburg Mini Case Study Episode(情节) 1: The 1st version is implemented Episode 2: A mistake is found – 10s —— too slow —— implementation fault: double – Changes double to float Episode 3: Revise – 4.5s —— still slow —— poor image recognition algorithm – A faster algorithm is used —— 1s Episode 4: A new design is adopted – Development is complete Episode 5: A few years later – Hardware changed, software has to be changed

Evolution Tree Model Winburg Mini Case Study ◆Development .Maintenance Requirements Requirements3 ↓ Analysis Analysis3 Design Design3 Design4 Implementation Implementation2 Implementation3 Implementation4 Episode 1 Episode 2 Episode 3 Episode 4

Slide 2.8 8/50 Evolution Tree Model Winburg Mini Case Study

Waterfall Model The linear life cycle model with feedback(反馈)loops Requirements The waterfall model cannot show the order of events Analysis Design 这是一种理想化的开 发过程，实际的软件 开发过程是曲折的。 Implementation Development Maintenance

Slide 2.9 9/50 Waterfall Model The linear life cycle model with feedback(反馈) loops The waterfall model cannot show the order of events 这是一种理想化的开 发过程，实际的软件 开发过程是曲折的

扩展内容：Naterfall Models理想化的方案 Communication Real projects rarely follow the Project initiation sequential flow. Requirements gathering Customers usually can't Planning state all requirements .Estimating explicitly. Scheduling and tracking A working version will not be available until Modeling late in the project ·Analysis and design time-span. Classic Construction Code and test Life Cycle Deployment ·Delivery Support and feedback

Slide 2.10 10/50 扩展内容： Waterfall Models 理想化的方案