软件工程实践者的研究方法chapter21.ppt

1,These slides are designed to accompany Software Engineering:A Practitioners Approach,7/e(McGraw-Hill 2009).Slides copyright 2009 by Roger Pressman.,Chapter 21,Project Scheduling,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.,例蛊踏谷炔翁米喻请牡盒匙祟刺严诈傲程弦烘刻智各告梆娱搁痒虞条躁偏软件工程-实践者的研究方法chapter_21软件工程-实践者的研究方法chapter_21,2,These slides are designed to accompany Software Engineering:A Practitioners Approach,7/e(McGraw-Hill 2009).Slides copyright 2009 by Roger Pressman.,Why Are Projects Late?,an unrealistic deadline established by someone outside the software development groupchanging customer requirements that are not reflected in schedule changes;an honest underestimate of the amount of effort and/or the number of resources that will be required to do the job;predictable and/or unpredictable risks that were not considered when the project commenced;technical difficulties that could not have been foreseen in advance;human difficulties that could not have been foreseen in advance;miscommunication among project staff that results in delays;a failure by project management to recognize that the project is falling behind schedule and a lack of action to correct the problem,惯廉蒙掸抨鸯培鹃饶漫缺腋谋骗新汹羽队莽褐填故栅康葫挥甲魔喜煽摇拱软件工程-实践者的研究方法chapter_21软件工程-实践者的研究方法chapter_21,3,These slides are designed to accompany Software Engineering:A Practitioners Approach,7/e(McGraw-Hill 2009).Slides copyright 2009 by Roger Pressman.,Scheduling Principles,compartmentalizationdefine distinct tasksinterdependencyindicate task interrelationship effort validationbe sure resources are availabledefined responsibilitiespeople must be assigneddefined outcomeseach task must have an outputdefined milestonesreview for quality,值葬娘辉吊婚陨纪狭音不痪姜徒柳蒜迁娩粹淌舒廊绘得盈乓得赤召厩滁闯软件工程-实践者的研究方法chapter_21软件工程-实践者的研究方法chapter_21,4,These slides are designed to accompany Software Engineering:A Practitioners Approach,7/e(McGraw-Hill 2009).Slides copyright 2009 by Roger Pressman.,Effort and Delivery Time,坟凤兆惊扇箍因必帜兰勘诺阻涎骄距傻贯平澜仙渝佃笑氰骡祈希丙旬巷慰软件工程-实践者的研究方法chapter_21软件工程-实践者的研究方法chapter_21,5,These slides are designed to accompany Software Engineering:A Practitioners Approach,7/e(McGraw-Hill 2009).Slides copyright 2009 by Roger Pressman.,Effort Allocation,“front end”activities customer communication analysis design review and modificationconstruction activities coding or code generationtesting and installation unit,integration white-box,black box regression,苍溯衫陛脂命豁扯租兆肄搭莱勺潞柠手守舶婪添褪筋投盂鼎硬虑莉故怂封软件工程-实践者的研究方法chapter_21软件工程-实践者的研究方法chapter_21,6,These slides are designed to accompany Software Engineering:A Practitioners Approach,7/e(McGraw-Hill 2009).Slides copyright 2009 by Roger Pressman.,Defining Task Sets,determine type of projectassess the degree of rigor requiredidentify adaptation criteriaselect appropriate software engineering tasks,纫汇迪额尖谣葬秘氯甜此参春冻正乒嗓须扭撑吕统饺面枯赘卫前马润晋永软件工程-实践者的研究方法chapter_21软件工程-实践者的研究方法chapter_21,7,These slides are designed to accompany Software Engineering:A Practitioners Approach,7/e(McGraw-Hill 2009).Slides copyright 2009 by Roger Pressman.,Task Set Refinement,1.1 Concept scoping determines the overall scope of the project.,Task definition:Task 1.1 Concept Scoping 1.1.1Identify need,benefits and potential customers;1.1.2Define desired output/control and input events that drive the application;Begin Task 1.1.21.1.2.1FTR:Review written description of need FTR indicates that a formal technical review(Chapter 26)is to be conducted.1.1.2.2Derive a list of customer visible outputs/inputs1.1.2.3FTR:Review outputs/inputs with customer and revise as required;endtask Task 1.1.21.1.3Define the functionality/behavior for each major function;Begin Task 1.1.31.1.3.1FTR:Review output and input data objects derived in task 1.1.2;1.1.3.2Derive a model of functions/behaviors;1.1.3.3FTR:Review functions/behaviors with customer and revise as required;endtask Task 1.1.31.1.4Isolate those elements of the technology to be implemented in software;1.1.5Research availability of existing software;1.1.6Define technical feasibility;1.1.7Make quick estimate of size;1.1.8Create a Scope Definition;endTask definition:Task 1.1,is refined to,地荔意踩骄筷舔掂仙屑缀募逻戒来残燎叉百余侵帐朱沦束出蒂今抄脸玖篆软件工程-实践者的研究方法chapter_21软件工程-实践者的研究方法chapter_21,8,These slides are designed to accompany Software Engineering:A Practitioners Approach,7/e(McGraw-Hill 2009).Slides copyright 2009 by Roger Pressman.,Define a Task Network,后郊星时女倘晶捷镐毕串攫泊鼠夺挤请定炉泄瑚君喻谩嘘综恍鲍南纲碗膀软件工程-实践者的研究方法chapter_21软件工程-实践者的研究方法chapter_21,9,These slides are designed to accompany Software Engineering:A Practitioners Approach,7/e(McGraw-Hill 2009).Slides copyright 2009 by Roger Pressman.,Timeline Charts,淹阎苑乏躁赋吓织剔撑宿炸桅屈沾耐韵登橱凑萨脱伙浆脓萤疼冻砰叙食翠软件工程-实践者的研究方法chapter_21软件工程-实践者的研究方法chapter_21,10,These slides are designed to accompany Software Engineering:A Practitioners Approach,7/e(McGraw-Hill 2009).Slides copyright 2009 by Roger Pressman.,Use Automated Tools toDerive a Timeline Chart,虹唤拐畴乓祥匀哮吞硫既渭贱揖垂忧校褂牛狱砖挪哑猾烛创胃狂座缀碎驶软件工程-实践者的研究方法chapter_21软件工程-实践者的研究方法chapter_21,11,These slides are designed to accompany Software Engineering:A Practitioners Approach,7/e(McGraw-Hill 2009).Slides copyright 2009 by Roger Pressman.,Schedule Tracking,conduct periodic project status meetings in which each team member reports progress and problems.evaluate the results of all reviews conducted throughout the software engineering process.determine whether formal project milestones(the diamonds shown in Figure 27.3)have been accomplished by the scheduled pare actual start-date to planned start-date for each project task listed in the resource table(Figure 27.4).meet informally with practitioners to obtain their subjective assessment of progress to date and problems on the horizon.use earned value analysis(Section 27.6)to assess progress quantitatively.,赡瞩饭裤俏臃易瞒绥焦滇手膳圃辟旱篮铺聊浙们珊警啄纽腮燎爹膛弘田庶软件工程-实践者的研究方法chapter_21软件工程-实践者的研究方法chapter_21,12,These slides are designed to accompany Software Engineering:A Practitioners Approach,7/e(McGraw-Hill 2009).Slides copyright 2009 by Roger Pressman.,Progress on an OO Project-I,Technical milestone:OO analysis completed All classes and the class hierarchy have been defined and reviewed.Class attributes and operations associated with a class have been defined and reviewed.Class relationships(Chapter 8)have been established and reviewed.A behavioral model(Chapter 8)has been created and reviewed.Reusable classes have been noted.Technical milestone:OO design completedThe set of subsystems(Chapter 9)has been defined and reviewed.Classes are allocated to subsystems and reviewed.Task allocation has been established and reviewed.Responsibilities and collaborations(Chapter 9)have been identified.Attributes and operations have been designed and reviewed.The communication model has been created and reviewed.,高匈炳眉熊襄材肝腊剥拙息第庭喘败无册侥菊墙奠善恿逢坑艳最与萌喝丰软件工程-实践者的研究方法chapter_21软件工程-实践者的研究方法chapter_21,13,These slides are designed to accompany Software Engineering:A Practitioners Approach,7/e(McGraw-Hill 2009).Slides copyright 2009 by Roger Pressman.,Progress on an OO Project-II,Technical milestone:OO programming completedEach new class has been implemented in code from the design model.Extracted classes(from a reuse library)have been implemented.Prototype or increment has been built.Technical milestone:OO testingThe correctness and completeness of OO analysis and design models has been reviewed.A class-responsibility-collaboration network(Chapter 6)has been developed and reviewed.Test cases are designed and class-level tests(Chapter 19)have been conducted for each class.Test cases are designed and cluster testing(Chapter 19)is completed and the classes are integrated.System level tests have been completed.,犬智佳丹鲜泪庚垮团依屯歇食性愈集凳肺镣边陕团辜术犁蓑骑债津同特叼软件工程-实践者的研究方法chapter_21软件工程-实践者的研究方法chapter_21,14,These slides are designed to accompany Software Engineering:A Practitioners Approach,7/e(McGraw-Hill 2009).Slides copyright 2009 by Roger Pressman.,Earned Value Analysis(EVA),Earned valueis a measure of progressenables us to assess the“percent of completeness”of a project using quantitative analysis rather than rely on a gut feeling“provides accurate and reliable readings of performance from as early as 15 percent into the project.”Fle98,倒畦婿桓境伺颓夷啮弹菏羌膜嫡枉芝铬过枉承潦穆翟励奥请慢倾屎鸿捂氖软件工程-实践者的研究方法chapter_21软件工程-实践者的研究方法chapter_21,15,These slides are designed to accompany Software Engineering:A Practitioners Approach,7/e(McGraw-Hill 2009).Slides copyright 2009 by Roger Pressman.,Computing Earned Value-I,The budgeted cost of work scheduled(BCWS)is determined for each work task represented in the schedule.BCWSi is the effort planned for work task i.To determine progress at a given point along the project schedule,the value of BCWS is the sum of the BCWSi values for all work tasks that should have been completed by that point in time on the project schedule.The BCWS values for all work tasks are summed to derive the budget at completion,BAC.Hence,BAC=(BCWSk)for all tasks k,罐娥厄寿熊填辗碟纱排及欠荚教士豌乍聪空萎烃诸荤吻唇嫡番川缠炮挪障软件工程-实践者的研究方法chapter_21软件工程-实践者的研究方法chapter_21,16,These slides are designed to accompany Software Engineering:A Practitioners Approach,7/e(McGraw-Hill 2009).Slides copyright 2009 by Roger Pressman.,Computing Earned Value-II,Next,the value for budgeted cost of work performed(BCWP)is computed.The value for BCWP is the sum of the BCWS values for all work tasks that have actually been completed by a point in time on the project schedule.“the distinction between the BCWS and the BCWP is that the former represents the budget of the activities that were planned to be completed and the latter represents the budget of the activities that actually were completed.”Wil99 Given values for BCWS,BAC,and BCWP,important progress indicators can be computed:Schedule performance index,SPI=BCWP/BCWSSchedule variance,SV=BCWP BCWSSPI is an indication of the efficiency with which the project is utilizing scheduled resources.,誉则缔僻疗丝烽终霄铰覆撵栅潦悲茄参占氧惶庭惦领蛹做衍炎讳锚冤弓焙软件工程-实践者的研究方法chapter_21软件工程-实践者的研究方法chapter_21,17,These slides are designed to accompany Software Engineering:A Practitioners Approach,7/e(McGraw-Hill 2009).Slides copyright 2009 by Roger Pressman.,Computing Earned Value-III,Percent scheduled for completion=BCWS/BACprovides an indication of the percentage of work that should have been completed by time t.Percent complete=BCWP/BACprovides a quantitative indication of the percent of completeness of the project at a given point in time,t.Actual cost of work performed,ACWP,is the sum of the effort actually expended on work tasks that have been completed by a point in time on the project schedule.It is then possible to computeCost performance index,CPI=BCWP/ACWPCost variance,CV=BCWP ACWP,斜恒堰腆审莎蹭井懂搂见释返戌撞关榜赘疟驴蝴包债疏完诈庶诛碾嫩饮由软件工程-实践者的研究方法chapter_21软件工程-实践者的研究方法chapter_21,