1什么是软件项目管理.ppt

1、generic phases of software engineering,Layered Software Engineering,Software Process Models,Tools and techniques for process modeling: Static modeling(Lai notation) and dynamic modeling(system dynamics),Waterfall Model,Prototyping Model,Incremental Model,Spiral Model,Last class review,Tracking proje

2、ct progress Project personnel and organization Effort and schedule estimate Risk management Using process modeling with project planning,Chapter three Planning and Managing Projects,问题 1.什么是软件项目管理？ 2.软件项目管理的内容是什么？ 3.如果我是项目经理，我应该做什么 4.我可以胜任软件项目管理吗？,1995年SEI统计，美国共取消了810亿美元的商业软件项目，其中31的项目未做完就被取消，53的软件项

3、目进度通常要延长50%的时间，只有9的软件项目能够及时交付并且费用也控制在预算之内。,2000年TechRepublic公司发表了有关IT项目的调查结果。该调查是以北美的1375个IT专家为对象实施问卷调查进行的。根据此调查，IT项目中有40%失败，这些项目的平均成本每年花费100万美元。,if a post mortem were to be conducted for every project,it is very likely that a consistent theme would be encountered:project management was weak,3.1 Tra

4、cking Progress,Usually, customers have several questions to be answered: Do you understand my problems and my needs? Can you design a system that will solve my problem or satisfy my needs? How long will it take you to develop such a system? How much will it cost to have you develop such a system?,A

5、Project Schedule describes the software development cycle for a particular project by enumerating the phases or stages of a project and breaking each into discrete tasks or activities to be done. The schedule also portrays the interactions among these activities and estimates the time that each task

6、 or activity will take.,Milestone: some events, and they indicate to us and our customers that a measurable level of progress has been made.,The distinguishing between activities and milestones: A activity is a part of the project that takes place over a period of time; A milestone is the completion

7、 of an activity and occurs at a particular point in time.,Work breakdown structure,Work Breakdown and Activity Graphs,The four parameters to describe each activity: A precursor: is an event or set of events that must occur before the activity can begin, it describes the set of conditions that allows

8、 the activity to begin. The duration: is the length of time needed to complete the activity. The due time: is the date by which the activity must be completed. The endpoint: is usually a milestone or deliverable, and represents the end of the activity. An activity graph: the nodes of the graph are t

9、he project milestones, and the lines linking nodes represent the activities involved.,Estimating Completion,Critical Path Method(CPM) The paths can show us the minimum amount of time it will take to complete the project, given our estimates of each activitys duration. CPM reveals those activities th

10、at are most critical to completing the project on time.,Slack time= available time real time Slack time= latest start time earliest start time,The critical path is the one for which the slack time at every node is zero. And it determines whether or not the project is on schedule.,The bar chart,Tools

11、 to Track Progress,Gantt Chart: a depiction of the project where the activities are shown in parallel, with the degree of completion indicated by a color or icon, the chart helps to understand which activities can be performed concurrently, and also to see which items are on the critical path.,Speci

12、fication approved,budget approved,schedule approved,plan approved,design approved,design approved,TODAY,3.3 Effort Estimation,The project budget pays for several types of costs: facilities, staff, methods, and tools,facilities,staff,methods,tools,Effort,Expert Judgment,Method 1: calculate the averag

13、e of estimates. Method 2: sit a meeting to make the experts agree on some estimate Method 3: Deiphi technology,Every expert estimates; Estimate in meeting; ai-the possibility of software minimal size mi-the most possibility of software size bi-the possibility of software maximal size Ei =(ai +4mi +

14、bi)/6 Discuss and estimate again in meeting Get an estimate with secrete ballot,Method 4: software cost matrix,A system,Old and Easy I/O module: 100 LOC New and Hard Algorithm module: 200 LOC Old and Medium Data management module: 100 LOC,Cost=(10017)+(200 35)+(100 31)=11800$,Algorithmic Methods,IBM

15、 model E=5.25S0.91 S is the estimated size of the system, E is the effort(PM). meta-model E=5.5+0.73S1.16 if R=(actual effort)E/(predicted effort)E then ERadj=,3. COCOMO (Constructive Cost Model),COCOMO estimation process reflects three major stages of any development project: Stage 1: projects buil

16、d prototypes to resolve high-risk issues involving user interfaces, software and interaction, performance, or technological maturity. COCOMO estimates size in application points. Stage 2: the early design stage, the designers must explore alternative architectures and concepts of operation. COCOMO e

17、stimates size in function points. Stage 3: the postarchitecture stage, sizing can be done in terms of function points or lines of code,.,The basic form of COCOMO: E=bScm(X) Where the initial size-based estimate bSc is adjusted by the vector of cost driver information m(X),Finding the Model for your

18、Situation two statistics to help you in assessing the accuracy: PRED: PRED(x/100) is the percentage of projects for which the estimate is within x%100 of the actual value. MMRE: is the mean magnitude of relative error.,3.4 Risk Management,What is risk? Risk pays more attention to the future events.

19、Risk relates to changing. Risk relates to choice and the uncertainty involved in choice., The characteristics of risk:, uncertainty The event that characterizes the risk may or may not happen; loss If the risk becomes a reality, unwanted losses will occur.,Distinguish risks from other project events

20、 by looking for three things: A loss associated with the event. The loss associated with a risk is called the risk impact. The likelihood that the event will occur. The likelihood of the risk, measured from 0 (impossible) to1 (certainty) id called the risk probability. When the risk probability is 1

21、, it is called a problem. The degree to which we can change the outcome. Risk control involves a set of actions taken to reduce or eliminate a risk.,Risk exposure = risk impact risk probability There are two major sources of risk: Generic risks: those common to all software projects, such as misunde

22、rstanding the requirements, losing key personnel, or allowing insufficient time for testing. Project-specific risks: threats that result from the particular vulnerabilities of the given project.,Risk Management Activities,risk impact risk probability = Risk exposure,The probability of an unwanted ou

23、tcome: P(UO) The loss associated with unwanted outcome:L(UO),There are three strategies for risk reduction: Avoiding the risk, by changing requirements for performance or functionality Transferring the risk, by allocating risks to other systems or by buying insurance to cover any financial loss shou

24、ld the risk become a reality Assuming the risk, by accepting it and controlling it with the projects resources,Risk leverage:,3.5 Project Plan,Project scope,Project schedule,Project team organization,Technical description of the proposed system,Project standards, procedures, and proposed techniques

25、and tools,Quality assurance plan,Configuration management plan,Documentation plan,Data management plan,Resource management plan,Test plan,Training plan,Security plan,Risk management plan,Maintenance plan,Review,The project schedule Work breakdown structure (phase-step-activity) An activity VS a mile

26、stone An activity graph The Critical Path Method Gantt chart,Project plan,Project personnel Effort estimation (Expert judgement and Algorithmic methods),项 目 管 理 案 例 分 析,1.整体性案例 Government Business Process Automation 2 专项讨论案例 关于进度问题,Government Business Process Automation 某城市人民政府进行机构改革，新成立了一个部门城市管理办公室

27、，负责城市水电、交通、环保、绿地等基础设施以及城市应急处理工作。为了使得新成立部门高效率运转，政府决定利用信息系统辅助该部门的日常业务。经过商讨，最终决定投资2500万元建立三套信息系统，一套是办公自动化系统，一套是数据采集与交换系统，一套是城市应急指挥调度系统，三个系统作为一个项目进行招标，经过激烈的竞争，最终选取了在系统集成、MIS、GIS方面经验丰富的A公司，项目建设周期为1年。 A公司经讨论确定成立一个由26人组成的项目开发小组，并制订了大致的开发计划如下： 1. 前期准备工作 一周 2. 项目开发工作 9个月 3. 系统试运行 2个月 4. 系统验收 15天,请你试着回答以下一些问题

28、： 1.你认为9个月完成项目开发有可能吗，依据是什么,2.根据你对城市管理的了解和猜测，试着评估一下这个项目拥 有的资源。 3.请为该项目建立一个风险表。 4.选择你熟悉的工具确定这个项目的生存周期和项目进度表以及 人员分工组织。 5.为了确保项目质量，请谈一谈如何进行复审以及复审的时间、 内容、方式。 6.请为该项目建一个配置管理库。 7.制订一份完整的软件开发计划书，格式自定。,1.你认为9个月完成项目开发有可能吗，依据是什么,合计：99451 功能点计算：99451 * (0.65 + 0.01 * (5+5+0+5+0+2+0+2+1+3+3+3+0+5) = 98456.49 按照以

29、往项目开发经验，每个人每月能够完成的功能点数为450左右，则26个人9个月能够完成功能点105300。,结论：9个月能够完成项目，但是项目周期需要设计的比较紧凑（此外初期的功能点估算往往误差较大，需要在设计阶段修正）,2.根据你对城市管理的了解和猜测，试着评估一下这个项目拥 有的资源。,软硬件环境方面：本项目资金充裕，可以购置足够的硬件和软件工具，因此能够保证硬件和软件工具在项目开发任何阶段可用。 可复用组件方面：本项目无可以直接复用的软件组件，完全需要自行开发 人员方面：需要分解工作任务，建立工作任务之间的并行关系，并根据工作进度详细安排对人员组织进行计划,3.请为该项目建立一个风险表。,应

30、建立类似下表的风险评估单，责任人应是明确的，并且不与其它资源发生冲突,4.选择你熟悉的工具确定这个项目的生存周期和项目进度表以及人员分工组织。,由于系统的复杂性和工作量，项目开发采用风险最小的原型法，大致分成4个阶段： 1.界面原型阶段 以用户界面为主设计原型，反复进行直到用户满意，同时完成需求分析 2.设计原型阶段 以系统结构、模块结构为主设计原型，与用户交流反映不同设计的比较，同时完成系统设计 3.功能原型阶段 在原型基础上实现系统功能，将原型变为产品 4.集成阶段 将三个系统集成起来 根据这样的进度安排，项目定义了三个里程碑：界面里程碑（需求里程碑）；设计里程碑、集成里程碑（系统里程碑）

31、。下表为项目进度甘特图,按照这样的进度计划，全体人员分成三个小组，即办公自动化小组、数据采集小组、应急指挥小组，每个小组又细分成数据设计人员、服务设计人员、代理设计人员、客户设计人员，每个小组设立两个小组长，一个负责技术协调，一个负责评审、质证、风险控制、绩效考核等管理工作,5.为了确保项目质量，请谈一谈如何进行复审以及复审的时间、 内容、方式。,提供三种复审方式 小组内部复审,在小组内部进行，需要提交复审报告，由小组长组织 项目组复审，在项目组内部进行，需要提交复审报告，由项目经理组织 外部复审，邀请客户代表、技术经理参加，需要提交正式的复审计划书、复审会议纪要、复审意见表、复审报告，只有里

32、程碑和基线变更才需要进行外部复审，由项目经理组织,在项目进行的不同阶段，先后出现了一些异常情况，请根据情况回答问题 .在项目进行了1个月后，发现需求中要求实现与电力、交通、自来水等等十二个公司之间已经建成的监控系统之间进行数据交换，这些系统具有不同的物理数据库，不同的传输协议，不同的文件格式，在技术上存在很大的困难，这是原先没有预计到的。 在项目进行到4个月后，在质量审计活动中发现大部分项目都存在不同程度的质量问题，导致项目管理者处于矛盾之中：如果返工，则开发进度严重推延；但是如果继续下去，可能导致最终产品不合格，从而需要更多的试运行时间，最后进度还是拖延 在项目进行到6个月后，开始出现开发进

33、度拖延问题，6月初几乎每一个计划中任务都拖延半天到一天，到6月下旬计划开始拖延三天甚至一周 请仔细分析这三种情况，并分别制订具体的行动计划,以上三种现象是软件项目常见的问题，即没有预料的技术障碍、质量问题和进度拖延。 对于第一个问题，客观原因是缺乏技术经验，主观原因是工作量度量和风险控制计划不当造成的，碰到这种情况，不仅需要进行技术攻关，而且需要对原有项目开发计划的所有内容重新进行评估，看来拖延是不可避免的，这也是项目组最艰难的时期。 对于第二个问题，导致的原因可能是多方面的（进度太紧、奖惩机制、管理者能力）。首先应对整个项目组的生产率进行评估，根据评估结论决定是否降低质量标准，如果项目组的生产率完全适应质量计划，则说明人为因素导致质量下降 对于第三个问题，明显是属于进度计划和工作任务分解不合理造成的，主要是指在制订计划时忽略了最早完成和最晚完成之间的差，从而失去了控制进度的余地，只有重新修正进度和分解任务，使得并行程度更高，才能赶回进度，否则拖延是不可避免的,进度拖延了 XX公司是一家专门从事系统集成和应用软件开发的公司，公司目前有员工50多人， 公司有销售部、软件开发部、系统网络部等业务部门，其中销售部主要负责进行公司服务和产