軟體開發管理 期中複習

Overview

Software development lifecycle (SDLC)

• 5 stages: Planning, Analysis, Design, Implementation, Maintenance

ITPM methodology

• 4 PM Objectives:

  

  pm iron triangle

• Project Liftcycle (PLC)

  

• 5 phases: Initialization > Planning > Execution > Closure > Evaluation

• SDLC happened at Execution phase

4 lessons learned

• reusable code
• best practices
• new risks & how the team dealt
• actual data

5 PM Processes

• Initiating > Planning > Executing > Monitoring&Controlling > Closing
• happened each phase in PLC

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Project Initialization

define measurable organizational value (MOV)

• should be measurable, verifiable, provide value, agreed
• 6 steps:
  1. Impact areas: customer / strategic / financial / operational / social
  2. Value: better / faster / cheaper / do more
  3. Metric
  4. Time: when the MOV be achieved?
  5. Verify: use MVPA
  6. Summarize: e.g. Increase 1000 new HL newsletter subscribers within 2 years

establish business case (BC)

• a proposal that states the reason for an IS investment

• 四大關鍵要素

  • MOV
  • Alts to achieve MOV
  • Cost-Benefit Analysis
  • Perceived risks

• 7 steps:

  1. Define MOV
  2. Seek support from BC stakeholders
  3. Identify alternatives (default + 5)
     • do nothing
     • 不使用 IT 來改善流程
     • 採用同業系統
     • 租用市面上的系統
     • 改造現有系統
     • 客製新系統
  4. Identify feasibilities
  5. Define cost and benifits
     • tangible or intangible?
     • one-time or recurring?
  6. Analyze alternatives using financial models and scoring models
  7. Propose and support the recommendation

• Financial models

  • Breakeven Point

    • $\text{Breakeven Point} = \text{Initial Investment} / \text{Net Profit Margin}$
    • 某系統開發成本 100,000 元，單品獲利 5 元 → 20,000

  • Cost-Benefit Analysis

    
    • $\text{Net Present Value} = -I_0 + \sum{\left(\text{Net Cash Flow} / (1+r)^t\right)}$
      • $I$: total cost
      • $r$: discount rate
      • $t$: time period
    • $\text{ROI} = \text{NPV} / I$

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Project Planning

• after BC approved, establish Project Infrastructure
  • Project Charter: 給所有 stakeholders 的原則
  • Project Plan: 給內部 stakeholders 的細節
• to close the planning phase need 3 things:
  • PC + PP + kick-off meeting

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Project Scope Mgt.

1. Planning scope
   • Scope is largely determined by requirements:
     • Functional requirement: to make the system run
     • Non-Functional requirement: to make the system run better
2. Collect requirements
   1. Gathering: interview, survey, field study, workshops, JAD...
   2. Prioritizing:
      • MoSCoW: must, should, could, want
      • The Kano Method: 缺少當然會失敗、一維需要維持、魅力是獲利關鍵
        
   3. Defining (the 7 criterias)
      • correct: 符合所需
      • unambiguous: 定義明確
      • verifiable
      • consistent: 跟其他需求不衝突
      • complete: 描述需有使用者與動詞
      • traceable
      • modifiable
3. Defining Scope
   • scope statement: what is and what is not, to be delivered in the project?
   • product scope: what features need in the product?
     • using use-case diagram + context diagram
   • project scope: what deliverables need to support the development
     • using Deliverable Structure Chart
4. Creating WBS
   • a tool to define tasks to fulfill the deliverables
   • Tasks are the lowest level, each < 80 hrs
   • Work package is a group of tasks
   • we can define Milestones at the end of work package
   • three types:
     • procedure oriented: focus on process (suit for Waterfall)
     • product oriented: focus on output (suit for Agile)
     • hybrid
5. Verifying Scope
6. Controlling Scope
   • mitigates the 4 typical scope mgt. problems:
     • Scope Grope (定義不明確)
     • Scope Creep (增減原本不在範圍內的功能)
     • Scope Leap (範圍巨變)
     • Gold Plating (幫不必要的功能鍍金)
   • tools
     • Requirement Traceability Matrix (RTM):
       • House of Quality
         
     • Scope change request form

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Project Time Mgt.

1. Defining tasks using activity list

2. Sequencing tasks

   • 4 relationships:
     • Finish to Start (FS): 大隊接力
     • Finish to Finish (FF): 最後的 task 結束後專案才能結束
     • Start to Start (SS): 開始寫 testcase 之後測試才可以開始
     • Start to Finish (SF): 老師開始講課後助教才能離開
   • 4 dependencies:
     • Mandatory (強制)
     • Discretionary (不強制)
     • Extrenal (between project and non-project activities)
     • Internal (between project activities)

3. Estimating task resources

   • 3 major resources: People, Equipment, Material
   • consider technical difficulty & availability

4. Estimating task duration

   • Top-down: sponsor determine overall time, then breakdown with WBS
   • Bottom-up: task-owners determine task time, then sum up
   • Delphi Method: involves experience experts
   • 3-Point Estimate:
     • $\text{Estimate Time} = (o + 4r + p)/6$
       • $o$: optimistic completion time
       • $p$: pessimistic completion time
       • $r$: most likely completion time
       • obtain by previous project's actual data

5. Developing project schedule

   • establish the paths/network of tasks using PDM (Activity on Node) or ADM (Activity on Arrow)

   • evaluation using PERT

     
     • for per task: $ES, LS, EF, LF$ - slack time = $LS-EF$ = $LF-EF$ - Critical Path: the bottleneck path with 0 slack time

   • PERT 5 steps:

     1. establish WBS to obtain tasks
     2. determine the sequences of the tasks
     3. use 3-point estimation to compute duration
     4. establish project's PERT
     5. eastblish a Gnatt chart

6. Controlling the schedule

   • Time-Boxing

     • fixed time allocated to a planned task, stop working once time up
     • often used in Agile

   • Resource Leveling
     e.g. A1, A2, B1, B2 shared same resources

     
     • splitting a task need to consider cost for Interruption of switching and Resuming a task

   • Critical Chain Project Mgt. (CCPM)

     • people often inflate their estimateion since

       • your work depends on someone unreliable
       • past bad experience that things did not go as planned
       • the worry of project change

     • but project still late since

       • Student's Syndrome: 拖延症
       • Parkinson's Law: 如果提早匯報完成，下次能運用的時間可能會減少
       • Multitasking / Resource Contention: 通常一個人不會只參與一個 task

     • CCPM approach: place 3 safety buffers instead of adding safety to each task

       
       • Feeding buffer: add when a task is a feeder to tasks on critical path
       • Resource buffer: add when a task has shared resources - End-of-project buffer

   • Schedule Compression

     • Crashing (趕工)
       • increase cost to decrease the duration of tasks
     • Fast Tracking (同步進行)
       • parallel performaing the ordered tasks
       • no dependency between parallel tasks
       • only useful for tasks on critical path

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Project Cost Mgt.

• PM approach:

  1. Compute & Sum up direct costs of each tasks in WBS
  2. Add other costs for the project
     • Indirect costs: 日常營運支出，通常用 coefficient 來當參考
     • Sunk costs: 已發生的成本 (e.g. cost of previous failed project)
     • Learning curve
     • Reserves: 用於突發事件的預備金，無使用(風險管理得當)則成為獲利

• SE approach

  • non-coding work can be estimate by the PM approach

  • to estimate software program:

    • Lines of Code

    • Function Points

      • estimate based on functionality defined by users
      • available in the earlier stage
      • 5 function types in 2 categories
        • Data Function Type
          • ILF: Internal Logical File (內部資料庫) (讀取不算)
          • EIF: External Interface File (外部資料庫)
        • Transaction Function Type
          • EI: External Input
          • EO: External Output
          • EQ: External Inquiry
      • Early-phase FP:
        1. Obtain context diagram
        2. Indentify the 5 function types and weight by complexity level (given by company)
           • $\text{UFP} = \sum \text{weighted FP}$
        3. Consider adjustment factors by answering the 14 questions
           • $\text{VAF} = 0.65 + 0.01 \times \sum_{i=1}^{14}X_i$
        4. Calculate the adjusted FP
           • $\text{AFP} = \text{UFP} \times \text{VAF}$
      • Design-phase FP:
        • As layout become clearer, we can obtain following information to better determine the complexity:
          • RET: Record Element Type (sub-tables)
          • DET: Data Element Type (data field)
          • FTR: File Type Reference (# of tables = ILF + EIF)

    • COCOMO (COnstructive Cost Model)

      1. Decide Type	Organic	Semi-Detached	Embedded
      2. $\text{Effort} = M \times \text{KLOC}^N$	$M=2.4, N=1.05$	$M=3, N=1.12$	$M=3.6, N=1.2$
      3. $\text{Duration} = 2.5 \times \text{Effort}^N$	$N=0.38$	$N=0.35$	$N=0.32$
      4. $\text{People} = \text{Effort} / \text{Duration}$

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Project Risk Mgt.

• Definition:

  • Risk: the effect of uncertainty on objectives, includes both negative & positive impacts
  • If not well handle: Risk → Crisis (loss caused by risks) → Disaster
  • Residual Risk: same risk remains after all response implemented
  • Secondary Risk: side effects of implementing a response

• Risk Management:

  1. Create a Risk Plan

  2. Indentify Risk

     • common risks: Technical, Managerial, Organizational, Customer, Supplier
     • Systemic Framework: 從中心 (MOV) 開始，依序向外檢查每一層是否有危害到上一層的因素
     • Risk Register: register identified risks and assign risk owner

  3. Analyze Risks

     • Qualitative risk assessment: $\text{Risk Exposure} = \text{Probability} \times \text{Impact}$
       • Decision Tree Analysis
       • Risk Impact Table
       • Tusler's Risk Identification Scheme
       • Probability/Impact Risk Rating Matrix
     • Quantiitative: observe the likeliness of a risk by probability distribution

  4. Develop Risk Strategies

     • Strategies:

       • Accept/Ignore: for low prob. and low impact
       • Avoidance: eliminate the possibility
       • Mitigate: to reduce the likelihood or impact
       • Transfer: transfer risk ownership, e.g. buying insurance
       • Diversify: spreading risk out to limit negative effects on us
       • Escalate: reporting to higher level for help

     • Reserve:

       • 已知風險 → Contingency Reserve (CR): 風險發生時由 PM 支用
       • 未知風險 → Management Reserve (MR): 全公司共用，發生時由高層動用
       

  5. Monitor and Control

  6. Respond and Evaluate

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Project Progress Mgt.

• Burn-down chart: managing the progress to implement the scope
  
• Earned Value Method
  • Parameters:
    • Planned Value (PV): the budget we planned to pay for an task
    • Budgeted At Completion (BAC): total budget for project
    • Actual Cost (AC): actual cost we have to pay for completing an task
    • Earned Value (EV): the budget we should pay for the completed work
  • We expect to complete 4 tasks (10k each) in this month. (BAC = 40k) However only 2 task complete in the end (EV = 20k), and each task cost 15k. (AC = 30k)
    
  • Cost Metrics
    • Cost Variance: $\text{CV} = \text{EV} - \text{AC}$
    • Cost Performance Index: $\text{CPI} = \text{EV} / \text{AC}$
  • Schedule Metrics
    • Schedule Variance: $\text{SV} = \text{EV} - \text{PV}$
    • Schedule Performance Index: $\text{SPI} = \text{EV} / \text{PV}$
  • forecasting: Estimate at Completion (EAC)
    • typical (we believe the variances WILL continue): $\text{EAC} = \text{Cumulative AC} + (\text{BAC} - \text{Cumulative EV}) / \text{Cumulative CPI}$
    • atypical (we believe the variances WILL NOT continue): $\text{EAC} = \text{Cumulative AC} + (\text{BAC} - \text{Cumulative EV})$
• Managing by Issue
  • Anomalies (異常): cost, time , scope related
  • Defects (缺失): quality related
    • 沒有 follow SOP 也算缺失

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Project Quality Mgt.

• the 3 types of requirements:

  • Project: budget, time, resources, people
  • Product: include software and non-software deliverables
  • Process: how the products are made

• Costs of Quality (CoQ)

  • CoPQ: cost of poor qulity
    • ICF: internal costs (e.g. 測試時發現的錯誤)
    • ECF: external costs (e.g. 使用者客訴)
  • CoGQ: cost of good quality
    • AppC: appraisal costs (e.g. 評鑑、認證)
    • PrevC: prevention costs (e.g. 設計驗證、開發測試)
  

• 品管進化歷程: (quality by) Ispection → Manufactoring → Design → Management → Culture

• Quality Management Standards

  • For Product: 食品標章...
  • For Process: ISO, 6-Sigma, CMMI
  • CMMI (Capability Maturity Model Integration) v1.3
    • project's Maturity level is determined by process areas and their Capability levels
    • 22 process areas
      • each has specific goals, where each goal has specific proctices
      • develop generic goals and generic practices for sustainability

• Establish PQM Plan

  1. Establish Quality Policies
  2. Develop Metrics for selected Standard
     • consider the 3 types of requirements
  3. Plan Quality Assurance (QA)
     • V&V:
       • Verification (VER): Are we building the product in the right way?
         • focus on process
         • ensure the process are repeatable, the artifacts are of quality
       • Validation (VAL): Did we build the right product?
         • focus on product
         • ensure the system to serve user needs in intended environment
     • Methods of V&V:
       • Review (most VER):
         • Management review
         • Technical review
         • List-based inspection
         • Walk-through
         • Audit
       • Test (both):
         • unit testing
         • integration testing
         • systems testing
         • acceptance testing
         • regression testing
       • Simulation (most VAL)
       • Demonstration (most VAL)
       • Pilot Try (most VAL)
  4. Plan Quality Control (QC)
     • monitor the quality of results, take corrective actions on the deviations
     • QA 和 QC 的區分需要看成果的定義
       • 在成果產出之前的預防 → QA
       • 在成果產出之後的檢查 → QC
  5. Continual Improvement: PDCA, IDEAL