1什么是軟件項目管理.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,問題 1.什么是軟件項目管理？ 2.軟件項目管理的內(nèi)容是什么？ 3.如果我是項目經(jīng)理，我應(yīng)該做什么 4.我可以勝任軟件項目管理嗎？,1995年SEI統(tǒng)計，美國共取消了810億美元的商業(yè)軟件項目，其中31的項目未做完就被取消，53的軟件項

3、目進度通常要延長50%的時間，只有9的軟件項目能夠及時交付并且費用也控制在預(yù)算之內(nèi)。,2000年TechRepublic公司發(fā)表了有關(guān)IT項目的調(diào)查結(jié)果。該調(diào)查是以北美的1375個IT專家為對象實施問卷調(diào)查進行的。根據(jù)此調(diào)查，IT項目中有40%失敗，這些項目的平均成本每年花費100萬美元。,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),項 目 管 理 案 例 分 析,1.整體性案例 Government Business Process Automation 2 專項討論案例 關(guān)于進度問題,Government Business Process Automation 某城市人民政府進行機構(gòu)改革，新成立了一個部門城市管理辦公室

27、，負責城市水電、交通、環(huán)保、綠地等基礎(chǔ)設(shè)施以及城市應(yīng)急處理工作。為了使得新成立部門高效率運轉(zhuǎn)，政府決定利用信息系統(tǒng)輔助該部門的日常業(yè)務(wù)。經(jīng)過商討，最終決定投資2500萬元建立三套信息系統(tǒng)，一套是辦公自動化系統(tǒng)，一套是數(shù)據(jù)采集與交換系統(tǒng)，一套是城市應(yīng)急指揮調(diào)度系統(tǒng)，三個系統(tǒng)作為一個項目進行招標，經(jīng)過激烈的競爭，最終選取了在系統(tǒng)集成、MIS、GIS方面經(jīng)驗豐富的A公司，項目建設(shè)周期為1年。 A公司經(jīng)討論確定成立一個由26人組成的項目開發(fā)小組，并制訂了大致的開發(fā)計劃如下： 1. 前期準備工作 一周 2. 項目開發(fā)工作 9個月 3. 系統(tǒng)試運行 2個月 4. 系統(tǒng)驗收 15天,請你試著回答以下一些問題

28、： 1.你認為9個月完成項目開發(fā)有可能嗎，依據(jù)是什么,2.根據(jù)你對城市管理的了解和猜測，試著評估一下這個項目擁 有的資源。 3.請為該項目建立一個風險表。 4.選擇你熟悉的工具確定這個項目的生存周期和項目進度表以及 人員分工組織。 5.為了確保項目質(zhì)量，請談一談如何進行復審以及復審的時間、 內(nèi)容、方式。 6.請為該項目建一個配置管理庫。 7.制訂一份完整的軟件開發(fā)計劃書，格式自定。,1.你認為9個月完成項目開發(fā)有可能嗎，依據(jù)是什么,合計：99451 功能點計算：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、往項目開發(fā)經(jīng)驗，每個人每月能夠完成的功能點數(shù)為450左右，則26個人9個月能夠完成功能點105300。,結(jié)論：9個月能夠完成項目，但是項目周期需要設(shè)計的比較緊湊（此外初期的功能點估算往往誤差較大，需要在設(shè)計階段修正）,2.根據(jù)你對城市管理的了解和猜測，試著評估一下這個項目擁 有的資源。,軟硬件環(huán)境方面：本項目資金充裕，可以購置足夠的硬件和軟件工具，因此能夠保證硬件和軟件工具在項目開發(fā)任何階段可用。 可復用組件方面：本項目無可以直接復用的軟件組件，完全需要自行開發(fā) 人員方面：需要分解工作任務(wù)，建立工作任務(wù)之間的并行關(guān)系，并根據(jù)工作進度詳細安排對人員組織進行計劃,3.請為該項目建立一個風險表。,應(yīng)

30、建立類似下表的風險評估單，責任人應(yīng)是明確的，并且不與其它資源發(fā)生沖突,4.選擇你熟悉的工具確定這個項目的生存周期和項目進度表以及人員分工組織。,由于系統(tǒng)的復雜性和工作量，項目開發(fā)采用風險最小的原型法，大致分成4個階段： 1.界面原型階段 以用戶界面為主設(shè)計原型，反復進行直到用戶滿意，同時完成需求分析 2.設(shè)計原型階段 以系統(tǒng)結(jié)構(gòu)、模塊結(jié)構(gòu)為主設(shè)計原型，與用戶交流反映不同設(shè)計的比較，同時完成系統(tǒng)設(shè)計 3.功能原型階段 在原型基礎(chǔ)上實現(xiàn)系統(tǒng)功能，將原型變?yōu)楫a(chǎn)品 4.集成階段 將三個系統(tǒng)集成起來 根據(jù)這樣的進度安排，項目定義了三個里程碑：界面里程碑（需求里程碑）；設(shè)計里程碑、集成里程碑（系統(tǒng)里程碑）

31、。下表為項目進度甘特圖,按照這樣的進度計劃，全體人員分成三個小組，即辦公自動化小組、數(shù)據(jù)采集小組、應(yīng)急指揮小組，每個小組又細分成數(shù)據(jù)設(shè)計人員、服務(wù)設(shè)計人員、代理設(shè)計人員、客戶設(shè)計人員，每個小組設(shè)立兩個小組長，一個負責技術(shù)協(xié)調(diào)，一個負責評審、質(zhì)證、風險控制、績效考核等管理工作,5.為了確保項目質(zhì)量，請談一談如何進行復審以及復審的時間、 內(nèi)容、方式。,提供三種復審方式 小組內(nèi)部復審,在小組內(nèi)部進行，需要提交復審報告，由小組長組織 項目組復審，在項目組內(nèi)部進行，需要提交復審報告，由項目經(jīng)理組織 外部復審，邀請客戶代表、技術(shù)經(jīng)理參加，需要提交正式的復審計劃書、復審會議紀要、復審意見表、復審報告，只有里

32、程碑和基線變更才需要進行外部復審，由項目經(jīng)理組織,在項目進行的不同階段，先后出現(xiàn)了一些異常情況，請根據(jù)情況回答問題 .在項目進行了1個月后，發(fā)現(xiàn)需求中要求實現(xiàn)與電力、交通、自來水等等十二個公司之間已經(jīng)建成的監(jiān)控系統(tǒng)之間進行數(shù)據(jù)交換，這些系統(tǒng)具有不同的物理數(shù)據(jù)庫，不同的傳輸協(xié)議，不同的文件格式，在技術(shù)上存在很大的困難，這是原先沒有預(yù)計到的。 在項目進行到4個月后，在質(zhì)量審計活動中發(fā)現(xiàn)大部分項目都存在不同程度的質(zhì)量問題，導致項目管理者處于矛盾之中：如果返工，則開發(fā)進度嚴重推延；但是如果繼續(xù)下去，可能導致最終產(chǎn)品不合格，從而需要更多的試運行時間，最后進度還是拖延 在項目進行到6個月后，開始出現(xiàn)開發(fā)進

33、度拖延問題，6月初幾乎每一個計劃中任務(wù)都拖延半天到一天，到6月下旬計劃開始拖延三天甚至一周 請仔細分析這三種情況，并分別制訂具體的行動計劃,以上三種現(xiàn)象是軟件項目常見的問題，即沒有預(yù)料的技術(shù)障礙、質(zhì)量問題和進度拖延。 對于第一個問題，客觀原因是缺乏技術(shù)經(jīng)驗，主觀原因是工作量度量和風險控制計劃不當造成的，碰到這種情況，不僅需要進行技術(shù)攻關(guān)，而且需要對原有項目開發(fā)計劃的所有內(nèi)容重新進行評估，看來拖延是不可避免的，這也是項目組最艱難的時期。 對于第二個問題，導致的原因可能是多方面的（進度太緊、獎懲機制、管理者能力）。首先應(yīng)對整個項目組的生產(chǎn)率進行評估，根據(jù)評估結(jié)論決定是否降低質(zhì)量標準，如果項目組的生產(chǎn)率完全適應(yīng)質(zhì)量計劃，則說明人為因素導致質(zhì)量下降 對于第三個問題，明顯是屬于進度計劃和工作任務(wù)分解不合理造成的，主要是指在制訂計劃時忽略了最早完成和最晚完成之間的差，從而失去了控制進度的余地，只有重新修正進度和分解任務(wù)，使得并行程度更高，才能趕回進度，否則拖延是不可避免的,進度拖延了 XX公司是一家專門從事系統(tǒng)集成和應(yīng)用軟件開發(fā)的公司，公司目前有員工50多人， 公司有銷售部、軟件開發(fā)部、系統(tǒng)網(wǎng)絡(luò)部等業(yè)務(wù)部門，其中銷售部主要負責進行公司服務(wù)和產(chǎn)