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