软件工程实践者的研究方法chapter13cn软件质量保证.ppt

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1、These slides are designed to accompany Software Engineering:A Practitioners Approach,7/e(McGraw-Hill,2009).Slides copyright 2009 by Roger Pressman.1第十三章n软件质量保证软件质量保证Slide Set to accompanySoftware Engineering:A Practitioners Approach,7/e by Roger S.PressmanSlides copyright 1996,2001,2005,2009 by Roge

2、r S.PressmanFor non-profit educational use onlyMay be reproduced ONLY for student use at the university level when used in conjunction with Software Engineering:A Practitioners Approach,7/e.Any other reproduction or use is prohibited without the express written permission of the author.All copyright

3、 information MUST appear if these slides are posted on a website for student use.SQA元素n标准标准n评审与审核评审与审核 n测试相关测试相关n错误错误/缺陷收集与分析缺陷收集与分析n变更管理变更管理n培训培训 n供应商管理供应商管理n安全管理安全管理 n安全安全 n风险管理风险管理These slides are designed to accompany Software Engineering:A Practitioners Approach,7/e(McGraw-Hill 2009).Slides cop

4、yright 2009 by Roger Pressman.2SQA 组的角色In对于项目，准备一个对于项目，准备一个SQA 计划计划n计划标识了 准备执行的评估 准备执行的审计与复审 应用于项目的标准 错误报告和跟踪的过程 由SQA组构造的文档 给软件项目团队提供的反馈 n参与项目软件过程描述的定义n SQA 组复审项目过程描述是否与企业规定，内部软件标准，外部标准（如ISO-9001）一致 These courseware materials are to be used in conjunction with Software Engineering:A Practitioners Ap

5、proach,6/e and are provided with permission by R.S.Pressman&Associates,Inc.,copyright 1996,2001,20053SQA 组的角色IIn评审软件工程活动，用于验证这些活动与定义的软件工程过程的评审软件工程活动，用于验证这些活动与定义的软件工程过程的兼容性兼容性n 识别，记录和跟踪与该软件过程的偏差，并验证是否得到改正。n审核制定的软件工作产品，以验证其是否符合定义的软件过程中审核制定的软件工作产品，以验证其是否符合定义的软件过程中的相应部分。的相应部分。n确保软件工作及工作产品中出现的偏差已文档化，并且按照

6、文档确保软件工作及工作产品中出现的偏差已文档化，并且按照文档化的规程进行了处理化的规程进行了处理n记录所有不符合的部分，并报告给高层管理者记录所有不符合的部分，并报告给高层管理者These courseware materials are to be used in conjunction with Software Engineering:A Practitioners Approach,6/e and are provided with permission by R.S.Pressman&Associates,Inc.,copyright 1996,2001,20054SQA 目标n需求

7、质量需求质量n设计质量设计质量n代码质量代码质量n质量控制有效性质量控制有效性.These slides are designed to accompany Software Engineering:A Practitioners Approach,7/e(McGraw-Hill 2009).Slides copyright 2009 by Roger Pressman.5为什么SQA活动是值得的?These courseware materials are to be used in conjunction with Software Engineering:A Practitioners

8、Approach,6/e and are provided with permission by R.S.Pressman&Associates,Inc.,copyright 1996,2001,20056基于统计的SQAThese courseware materials are to be used in conjunction with Software Engineering:A Practitioners Approach,6/e and are provided with permission by R.S.Pressman&Associates,Inc.,copyright 19

9、96,2001,20057度量度量.如何增进质量的一个理解如何增进质量的一个理解 收集所有的缺陷信息收集所有的缺陷信息 找到缺陷的原因找到缺陷的原因 专向弥补缺陷的过程专向弥补缺陷的过程 Statistical SQAnInformation about software errors and defects is collected and categorized.nAn attempt is made to trace each error and defect to its underlying cause(e.g.,non-conformance to specifications,d

10、esign error,violation of standards,poor communication with the customer).nUsing the Pareto principle(80 percent of the defects can be traced to 20 percent of all possible causes),isolate the 20 percent(the vital few).nOnce the vital few causes have been identified,move to correct the problems that h

11、ave caused the errors and defects.These slides are designed to accompany Software Engineering:A Practitioners Approach,7/e(McGraw-Hill 2009).Slides copyright 2009 by Roger Pressman.8软件Six-Sigman“six sigma”这个术语来源于6个标准方差每百万个操作发生3.4个偏差它意味着非常高的质量标准。nSix Sigma 方法学定义了3个主要步骤:n定义n度量n分析n改进n控制These courseware

12、 materials are to be used in conjunction with Software Engineering:A Practitioners Approach,6/e and are provided with permission by R.S.Pressman&Associates,Inc.,copyright 1996,2001,20059软件可靠性n一个简单的可靠性的度量是mean-time-between-failure(MTBF),此处MTBF=MTTF+MTTRnMTTF（mean-time-to-failure）与MTTR（mean-time-to-re

13、pair）,n软件可用性是指在某个时间点上程序能够按照需求执行的概率。可用性=MTTF/(MTTF+MTTR)x 100%These courseware materials are to be used in conjunction with Software Engineering:A Practitioners Approach,6/e and are provided with permission by R.S.Pressman&Associates,Inc.,copyright 1996,2001,200510软件安全性nSoftware safety is a software

14、quality assurance activity that focuses on the identification and assessment of potential hazards that may affect software negatively and cause an entire system to fail.nIf hazards can be identified early in the software process,software design features can be specified that will either eliminate or

15、 control potential hazards.These courseware materials are to be used in conjunction with Software Engineering:A Practitioners Approach,6/e and are provided with permission by R.S.Pressman&Associates,Inc.,copyright 1996,2001,200511软件安全性n软件安全是一种软件质量保证活动，它主要用来识别和评估可能对软件产生负面影响并促使整个系统失效的潜在灾难。n如果能够在软件过程的早

16、期阶段识别出这些灾难，就可以指定软件设计特性来消除或控制这些潜在的灾难。These courseware materials are to be used in conjunction with Software Engineering:A Practitioners Approach,6/e and are provided with permission by R.S.Pressman&Associates,Inc.,copyright 1996,2001,200512ISO 9001:2000 标准nISO 9001:2000是适用于软件工程的质量保证标准。nISO 9001:2000 描述的质量要求涉及：管理者责任、质量体系、合同评审、设计控制、文件和资料控制、产品标识和可追溯性、过程控制、检验和实验、纠正及预防措施、质量记录的控制、内部质量审核、培训、服务以及统计技术等主题。These courseware materials are to be used in conjunction with Software Engineering:A Practitioners App