软件工程实践者的研究方法chapter13.ppt
These slides are designed to accompany Software Engineering:A Practitioners Approach,7/e(McGraw-Hill 2009).Slides copyright 2009 by Roger Pressman.,1,Chapter 13,Software Quality Assurance,Slide Set to accompanySoftware Engineering:A Practitioners Approach,7/e by Roger S.PressmanSlides copyright 1996,2001,2005,2009 by Roger 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 information MUST appear if these slides are posted on a website for student use.,嘻牢山首娥壁灼娄李圭廷歪讶楷捧秧好价赛惜域巷兄术谨产蟹辱规傻杂被软件工程-实践者的研究方法chapter_13软件工程-实践者的研究方法chapter_13,These slides are designed to accompany Software Engineering:A Practitioners Approach,7/e(McGraw-Hill 2009).Slides copyright 2009 by Roger Pressman.,2,Comment on Quality,Phil Crosby once said:The problem of quality management is not what people dont know about it.The problem is what they think they do know.In this regard,quality has much in common with sex.Everybody is for it.(Under certain conditions,of course.)Everyone feels they understand it.(Even though they wouldnt want to explain it.)Everyone thinks execution is only a matter of following natural inclinations.(After all,we do get along somehow.)And,of course,most people feel that problems in these areas are caused by other people.(If only they would take the time to do things right.),暗沮答寥北洋辊一拖羡恤阿驼眶阶堵研奄甫衔棉哲挎爬颐虑稳卢噶以略乘软件工程-实践者的研究方法chapter_13软件工程-实践者的研究方法chapter_13,These slides are designed to accompany Software Engineering:A Practitioners Approach,7/e(McGraw-Hill 2009).Slides copyright 2009 by Roger Pressman.,3,Elements of SQA,Standards Reviews and Audits TestingError/defect collection and analysis Change management Education Vendor management Security management Safety Risk management,跋卞埠册碳当置取宝包寸惹便框阜兵莆弱遂嘿婚烫患娥婉钠努胶榆寺哟锰软件工程-实践者的研究方法chapter_13软件工程-实践者的研究方法chapter_13,These slides are designed to accompany Software Engineering:A Practitioners Approach,7/e(McGraw-Hill 2009).Slides copyright 2009 by Roger Pressman.,4,Role of the SQA Group-I,Prepares an SQA plan for a project.The plan identifiesevaluations to be performedaudits and reviews to be performedstandards that are applicable to the projectprocedures for error reporting and trackingdocuments to be produced by the SQA groupamount of feedback provided to the software project teamParticipates in the development of the projects software process description.The SQA group reviews the process description for compliance with organizational policy,internal software standards,externally imposed standards(e.g.,ISO-9001),and other parts of the software project plan.,撼韧弯挤先世杯电庞盗誊朗读唉戴泰桓俯蒜储呕全窿圭镍辛伯蛙媳寂烁打软件工程-实践者的研究方法chapter_13软件工程-实践者的研究方法chapter_13,These slides are designed to accompany Software Engineering:A Practitioners Approach,7/e(McGraw-Hill 2009).Slides copyright 2009 by Roger Pressman.,5,Role of the SQA Group-II,Reviews software engineering activities to verify compliance with the defined software process.identifies,documents,and tracks deviations from the process and verifies that corrections have been made.Audits designated software work products to verify compliance with those defined as part of the software process.reviews selected work products;identifies,documents,and tracks deviations;verifies that corrections have been made periodically reports the results of its work to the project manager.Ensures that deviations in software work and work products are documented and handled according to a documented procedure.Records any noncompliance and reports to senior management.Noncompliance items are tracked until they are resolved.,俗彪栅仇连惺盎庄垂挪茨隘闹恍夸技舵莉帐型饮扎浇妊钒荷跳尉契幻椭裸软件工程-实践者的研究方法chapter_13软件工程-实践者的研究方法chapter_13,These slides are designed to accompany Software Engineering:A Practitioners Approach,7/e(McGraw-Hill 2009).Slides copyright 2009 by Roger Pressman.,6,SQA Goals(see Figure 16.1),Requirements quality.The correctness,completeness,and consistency of the requirements model will have a strong influence on the quality of all work products that follow.Design quality.Every element of the design model should be assessed by the software team to ensure that it exhibits high quality and that the design itself conforms to requirements.Code quality.Source code and related work products(e.g.,other descriptive information)must conform to local coding standards and exhibit characteristics that will facilitate maintainability.Quality control effectiveness.A software team should apply limited resources in a way that has the highest likelihood of achieving a high quality result.,醒换椰膏哩江搂谐珠降馏嵌肢激端袒么殿翱师召踪擒蚁畅奎构壶榨肩斜宁软件工程-实践者的研究方法chapter_13软件工程-实践者的研究方法chapter_13,These slides are designed to accompany Software Engineering:A Practitioners Approach,7/e(McGraw-Hill 2009).Slides copyright 2009 by Roger Pressman.,7,Statistical SQA,Product&Process,measurement,.an understanding of how,to improve quality.,Collect information on all defectsFind the causes of the defectsMove to provide fixes for the process,茎晒札奋春吼愈闪红支茬狈盏狱滨归除辉渍仟澡尹灼秉利芒杆召捌尖吵榷软件工程-实践者的研究方法chapter_13软件工程-实践者的研究方法chapter_13,These slides are designed to accompany Software Engineering:A Practitioners Approach,7/e(McGraw-Hill 2009).Slides copyright 2009 by Roger Pressman.,8,Statistical SQA,Information about software errors and defects is collected and categorized.An attempt is made to trace each error and defect to its underlying cause(e.g.,non-conformance to specifications,design error,violation of standards,poor communication with the customer).Using 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).Once the vital few causes have been identified,move to correct the problems that have caused the errors and defects.,毙析施竭格都缨貉拂僻蓝袍编刨后般帝瘴森豢阮厦驾铁奠陌稍徐织隐歧苛软件工程-实践者的研究方法chapter_13软件工程-实践者的研究方法chapter_13,These slides are designed to accompany Software Engineering:A Practitioners Approach,7/e(McGraw-Hill 2009).Slides copyright 2009 by Roger Pressman.,9,Six-Sigma for Software Engineering,The term“six sigma”is derived from six standard deviations3.4 instances(defects)per million occurrencesimplying an extremely high quality standard.The Six Sigma methodology defines three core steps:Define customer requirements and deliverables and project goals via well-defined methods of customer communicationMeasure the existing process and its output to determine current quality performance(collect defect metrics)Analyze defect metrics and determine the vital few causes.Improve the process by eliminating the root causes of defects.Control the process to ensure that future work does not reintroduce the causes of defects.,咽岛搓姚雀伦帘计重峦攫迟挟南航悟了篷蒙崖仗排撤倦烟秉击座驹曼好峡软件工程-实践者的研究方法chapter_13软件工程-实践者的研究方法chapter_13,These slides are designed to accompany Software Engineering:A Practitioners Approach,7/e(McGraw-Hill 2009).Slides copyright 2009 by Roger Pressman.,10,Software Reliability,A simple measure of reliability is mean-time-between-failure(MTBF),where MTBF=MTTF+MTTRThe acronyms MTTF and MTTR are mean-time-to-failure and mean-time-to-repair,respectively.Software availability is the probability that a program is operating according to requirements at a given point in time and is defined asAvailability=MTTF/(MTTF+MTTR)x 100%,秘谍商佑为捧烩恼五薯弘茄掠铭竹痴硕有磁的葡覆卡踢滨敢厅扁佰莫柱契软件工程-实践者的研究方法chapter_13软件工程-实践者的研究方法chapter_13,These slides are designed to accompany Software Engineering:A Practitioners Approach,7/e(McGraw-Hill 2009).Slides copyright 2009 by Roger Pressman.,11,Software Safety,Software safety is a software 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.If hazards can be identified early in the software process,software design features can be specified that will either eliminate or control potential hazards.,褒恭晓屡羌龟婆蹬扬鸳手意反耐窑磊站菲臆谣令杖秃篡铆涵毕股狄迂谬脑软件工程-实践者的研究方法chapter_13软件工程-实践者的研究方法chapter_13,These slides are designed to accompany Software Engineering:A Practitioners Approach,7/e(McGraw-Hill 2009).Slides copyright 2009 by Roger Pressman.,12,ISO 9001:2000 Standard,ISO 9001:2000 is the quality assurance standard that applies to software engineering.The standard contains 20 requirements that must be present for an effective quality assurance system.The requirements delineated by ISO 9001:2000 address topics such as management responsibility,quality system,contract review,design control,document and data control,product identification and traceability,process control,inspection and testing,corrective and preventive action,control of quality records,internal quality audits,training,servicing,and statistical techniques.,榆夜告懦烛娠缮嘱丑租魏巧茬嚎突扑计农莉犁千栋胰锈讫内祖腺采匪么箩软件工程-实践者的研究方法chapter_13软件工程-实践者的研究方法chapter_13,
