1 「 軟體採購程序改善計畫 SAPIP 」 - 由 “Section 804” 大法說起 CMMI-AM 2006 年 11 月 國防工業發展協會 科技顧問 尹守紀

2 內容 A. CMMI-AM （ CMMI-ACQ ）之緣由 ：源起於國會之 不滿 B. 美國採購缺失之實例 ：肇因於軟體複雜性劇增與系統工程 能力不足 C. 美國採購單位之改善措施 ：歸向於改善系統工程能量 D. 美國 SEI 規劃配套 CMMI-AM 之教育重點 E. 國內之可行方式 由系統工程檢視軟體採購之需求定 義程序 a) 由系統工程 (ISO/IEC-15288) 確認需求 b) 由 (IEEE/EIA-12207) 進行程序書規劃 c) 以 Products 角度建立 Program WBS d) 由 WBS 撰述 RFP 架構

3 A. CMMI-AM 之緣由：源起於國會之不滿 年美國政府管考辦公室或國家審計總署 (GAO) 針對 國防部有關系統與軟體改善提出建議報告，該報告中建議 採用 SEI 之 IDEAL Models 並列舉 SW-CMM 之相關內容以 改善專案品質；但美國國防部企圖以改進 DOD R( 已更名為 Defense Acquisition Guidebook) 方 式達成 SW-CMM Level-3( 或相近似 models) 以滿足 Software Process Improvement 部分 ( 但僅針對研發案 金額超過美金 $3.65 億或採購金額超過美金 $21.9 億之計 劃 ) ；在 DOD R 增列 Software Management 章節， 並明述承約商須具有 SEI 所發展或由採購單位認可同等 Model 之 Level-3 能力，若承約商無法達到前述目標應提 出 Risk Mitigation Plan ，前述之 Level-3 appraisement 效期為 2 年； GAO 在報告之 page 35 頁亦 提到 “Software Capability Maturity Model® (SW- CMM®), was designed to assist organizations in improving software development and maintenance processes.” ，未提到 Acquisition Phase 之適當方法；

4 CMMI-AM 之緣由 ( 續 ) 2. 由於前述建議報告未得到國防部正面回應， 2002 年 12 月 2 日通過之美國國會 2003 年度國防授權法案（ National Defense Authorization Act for Fiscal Year 2003 ）針 對前述之缺失提出 SEC Improvement of Software Acquisition Processes ，責令 (mandate) 國防 部執行重大武器系統採購計畫 (Major Defense Acquisition Program) 須進行軟體採購過程改善，同時在 Section 804 附註 Major Defense Acquisition Program 之定義應參用美國聯邦法典 section 139(a)(2)(B) of title 10, United States Code 之解釋，意即研發案金額超過 美金 $3 億或採構金額超過 $18 億者 ；

5 CMMI-AM 之緣由 ( 續 ) 3. Section 804 條列應執行事項有 1) 對於 (1)software acquisition planning, (2)requirements development and management, (3)project management/ oversight, 及 (4)risk management. 等程序應 有文件紀錄； 2) 對於計劃執行效能應進行度量評估暨進行持續 改善； 3) 採購專案之關鍵執行工程人員應具有適當之經 驗與軟體採購訓練； 4) 每一軍事採購單位應確實遵循既訂採購程序與 需求執行軟體相關專案採購； 國會於 Section 804 提出四項改 善領域

6 採購單位之程序改善承諾 ：美國國防部針對 Section 804 的改善措施 1. 美國國防部針對 Section 804 的要求，擬定了 8 項改善領域； 2. Section 804 責令國防部應於該法案生效日起 120 天內開始執行， 因此國防部各採購單位配合 Section 804 完成下列措施 ： 1) 成立 Software Acquisition Process Improvement Program (SAPIP) ， 2) 重新訂定諸如 Acquisition Guideline 之採購指引， 3) 參用實獲值工程 ANSI/EIA-748-A-1998 EVMS 進行效能監控， 4) 各單位依據需要分別選用 CMMI 、 SA-CMMR 、 FAA-ICMM 、 或混合使用以配合 SAPIP 執行 Acquisition Process Improvement ， ( 所選用類型極為繁雜；因此國防部認為有必 要規劃 CMMI-based acquisition model ，此即後續 CMMI- ACQ 之發軔；先期規劃有 CMMI Module for Acquisition ( sei/features/2005/1/feature htm) ，其對象係 針對 system project offices/program managers ( ) ； sei/features/2005/1/feature htmhttp:// ,21 美國國防 部增列為 八項改善 領域

Slide 7 FY03 Defense Authorization Act Section 804 Requires Services and applicable Agencies establish “software acquisition process improvement programs” within 120 days (March 2003) Army, Navy, Air Force MDA, DISA, DLA, DFAS, and Health Affairs Requires ASD(NII) and USD(AT&L) to… Prescribe uniformly applicable guidance Ensure compliance by Service/Agency Components Section 804 approach to Component implementation identified eight process improvement areas: 1)Acquisition Planning 2)Requirements Development and Management 3)Configuration management 4)Risk Management 5)Project Management and Oversight 6)Test and Evaluation 7)Integrated Team Management 8)Solicitation and Source Selection Past performance, Process maturity, Product maturity ,21 揭示採購單 位必須改善 之 8 項領域 ： Section 804 要求 領域 ： 美國國防部另增領域

© 2005 by Carnegie Mellon University CMMI Acquisition Module - Page M2-8 CMMI ® CMMI-AM and Project Management v0.1 CMMI Acquisition Module V 1.1 Engineering Support Project Management Project Planning Project Monitor and Control Integrated Project Management Risk Management Solicitation and Contract Monitoring Requirements Management Requirements Development Verification Validation Measurement and Analysis Decision Analysis and Resolution Transition to Operations and Support CMMI-AM Structure Key New for CMMI-AM ： Section 804 要求 領域 ： 美國國防部另增領域 SEI 配合 Section 804 規劃之 CMMI-AM 的架 構

9 B. 採購缺失之實例 ：肇因於軟體複雜性劇增 C-17 運輸機 Boeing 公司設計 （ 取得 CMMI SW/SE/IPPD/SS Level 5 ） 1985 年計畫開始規劃有 4 項軟體相關系統，估計有 164,000 lines-of-code 年檢討時軟體相關系 統遞增為 56 項，總計有 1,356,000 lines-of-code, 內含新增功能 643,000 lines-of-code,

© Copyright Lockheed Martin Corporation 2003 Joan Weszka 年由 LM Martine 所分享之 CMM/CMMI 效益

年 GAO 對 6 項合約成效之檢討 檢討結論 ： 預算超支、時程落後

© 2005 by Carnegie Mellon University CMMI Acquisition Module - Page M1-12 CMMI ® M1-Background v0.1 KSLOC F/A-18C/D SMUG/ RUG 14268K F/A-18E/F 17101K F/A-18C/D XN K F/A-18 Night Attack 3054k F/A-18C/D 2130K F-14D 416K F-14B 2866K A-7E 16K F-14 80K A-4 (ARBS) 16K A-6E 64K F/A-18A/B 943K F-14B 364K AV-8B Night Attack 1780K AV-8B Radar 3748K AH-1 NTS 1000K AH-1 764K A-E SWIP 364K AV-8B 764K Aircraft IOC, Year EA-6B ICAP2 BLK K E-A6B ICAP1 48K EA-6B ICAP2 BLK K EA-6B ICAP2 BLK K 0610 JSF UAVs NCW Inter-System Operability Increasing System Complexity 造成預算超支、時程落 後原因之ㄧ為軟體複雜 性劇增 複雜性為人月神話所歸 類於固有性軟體問題

© 2005 by Carnegie Mellon University CMMI Acquisition Module - Page M1-13 CMMI ® M1-Background v0.1 Functionality Provided by Software in DoD Systems is Increasing Ref: Defense Systems Management College F-4 A-7 F-111 F-15 F-16 B-2 F-22 造成預算超支、時程 落後原因之二為軟體 比重遽增 如人月神話之 “No silver bullets” 所敘述 將因為 Project Team 的溝通問題導致 Cost overruns and schedule delay

14 Industry Views - Current SE Issues based on Performance Factors Summit, June 2 & 3, 2004 Despite high maturity prime contractors (i.e. CMMI Level 5) there are still significant problems on major DoD programs Systems Engineering is often not performed because: –PM will not fund (viewed as “overhead”) –Programs tend to be “back-loaded”, insufficient front-end funds –PM voids contractor process maturity by tailoring critical items out of a program –PM typically feels need to start coding/designing immediately –Many major primes will not engage their subs in the top-level SE process (believing this to be sole responsibility of the prime) And yet Boeing only builds 38% of F/A-18 E/F, Lockheed 36% of F/A- 22, etc PM and contractor often unable to distinguish between real requirements and implied requirements (often driven by user representative) Requirements not properly interpreted/followed Many of the “software problems” on programs are not really rooted in software or software engineering, but are really software “content” issues (algorithms, operational flows, functional analysis) which is related to systems engineering

15 C. 採購單位之改善措施 ：歸向於改善系統 工程能量 美國國防部執行軟體採購程序改善 SAPIP 之架構

16 重點在 Pre-Acquisition Process 美國國防部執行軟體採購之程序

17 Operational Concept MNS STAR TRD Scenario Government Users/Operators Government Acquisition Contractor System Spec Verification Plan Seg X SpecSeg Y SpecSeg Z SpecSub X-1 Documentation Sub Z-1 Documentation Sub Y-1 Documentation CONOPS SPG TEMP ORD Government & Contractor Responsibilities CRD 參考 CMMI 之 Requirements Development [PA157.N101] 參考 CMMI 之 Requirements Development [PA157.N108] 有標準 規範可 參考 無標準 規範可 參考 (TEMP 除外 )

18 Acquisition 在 Life Cycle 之程序關係 (1) Disciplined Flexible Maturity Level ?????

19 Acquisition Process (based on 12207) Initiation describe needs define system reqr define software reqr (?) prepare acquisition plan define acceptance strategy Tender (RFP) document acquisition reqr determine processes define references to contract set review milestones Contract Preparation and Update establish supplier selection procedures select supplier tailor and involve parties negotiate contract Supplier Monitoring monitor in accordance with joint review and audit process supplement with verification and validation Acceptance and Completion prepare for acceptance including tests conduct acceptance review/testing accept deliverables assume configuration management 目前並無 Standards 敘 述 ”Needs” 之 activity ， CJCAI-3170 以外 可參考美 國採購 法 FAR 可參考採購部門 之程序書

20 美國國防部執行 SAPIP 之改善事項 1. 修定國防部之採購規範 Policy/Guidance 1) 採購管理部份： (1) DFARS 、 (2) DoD Directive Defense Acquisition System 、 (3)DoD Instruction Operation of the Defense Acquisition System 、 (4)Defense Acquisition Guidebook 2) 需求管理部份： (1)CJCSI E Joint Capabilities Integration and Development System 、 (2)CJCSM B Operation of the Joint Capabilities Integration and Development system 3) 各執行單位自行修訂相關之程序書 2. 針對 8 項 process area 進行流程改善且均一化各單位 之 Guidance 3. 補強採購程序之教育訓練 4. 有效監控各採購單位是否落實 Acquisition Guidance

21 美國國防部執行 SAPIP 之改善事項 ( 續 ) 5. 選商必須考量廠家 Past performance 並評估 P roduct maturity 與 Process maturity （方法可包括 CMMI 、 ISO 、 EIA-731 、 SDCE 、 J-STD-016 、 ISO/IEC 、 …. ，統稱之為 “best practices” ）  建立 software development and acquisition 之 best practices 的資料交換中心 (clearinghouse) 7. 強化 Life Cycle Cost 之 Acquisition Model ： Evolutional Acquisition Spiral Development model 8. 採用實獲值工程 (Applying Earned Value Management to Software) ：有助於了解軟體專案之 “ 健康 ” 狀態 9. 可考量採用 Best Practice (CMMI-AM 為其中之一 ) 對於採 購單位與專案計畫之 SAPIP 成效進行 measurement SDCE: Air Force Aeronautical System Center’s Software Development Capability Evaluation

CDSC-PM, 17 July DOTMLPFDOTMLPF MS A Analysis of Materiel Approaches Demo AoA Technology Development DAB JROC MS B MS C -- Materiel Process DOTLPF Change Functional Area Analysis Functional Area Functional Concept Integrated Architecture Overarching Policy NSS/NMS/Joint vision Joint Capstone Policy Feedback ICD Concept Refinement CD Oversight Requirements Acquisition Integrated Decision Meetings Increment 1 New MS B CDD DABJROC MS C CPD DABJROC Increment 2 Increment 3 Fig. 2, DoDI Requirements & Acquisition Process DoDI 文 件規範採購程序

23 Working Against the Plan As Work Is Performed, Earned Value Is Claimed and Actual Dollars Are Expended –earned value = budgeted cost of work performed (BCWP) –actual cost = actual cost of work performed (ACWP) Cost Variance (CV) –CV = BCWP - ACWP Schedule Variance (SV) –SV = BCWP - BCWS –units of dollars, NOT time! –INDICATOR of being “on plan” Percent Complete, Percent Spent –% complete = BCWP / BAC –% spent = ACWP / BAC Time Schedule End BAC BCWS ACWP BCWP CV SV Dollars Now 實獲值工程 EVMS

24 Work Instructions Applying Best Practices Tailoring Records Process Deployment Continuous Process Improvement Process Baseline Framework Standards Tailoring Validation Evaluation Performance Supporting Standards Standards-Based Knowledge Products IEEE/EIA ISO/IEC IEEE 830 IEEE 830 IEEE 830 Training Materials IEEE Standards- Based Training P&P PAL Action Plans Process Improvement Plan Training Materials Management Plans Performance Findings Evaluation Reports * From work by Paul Croll, Chairman of IEEE CS Software Engineering Standards Committee (SESC), 2002

25 D. 美國 SEI 規劃配套 CMMI-AM 之教育重點 a) 由 IDEAL Model 轉入 CMMI-AM b) PM 自行依據 SEI’s questions 執行 CMMI-AM Self- Assessment c) 強化 PM 與 Contractor 之間的 Information Exchange 、 Products Evaluation & Measurement 、 Schedule/Cost Evaluation & Measurement d) 強化需求工程以完成 Customer’s requirements e) 強化 Acquisition Method ： Evolutional Acquisition-Spiral Development

© 2005 by Carnegie Mellon University CMMI Acquisition Module - Page M6-26 CMMI ® M6-Process Improvement v0.1 Using IDEAL to adopt CMMI-AM 1 IDEAL: Initiate, Diagnose Establish, Act, Learning Set Context Stimulus for Change Set Priorities Plan Actions Create Solution Analyze & Validate Learning Acting Establishing Diagnosing Initiating Charact- erize Current & Desired State Develop Recom- endations Pilot/Test Solution Refine Solution Implement Solution Propose Future Actions Build Sponsorship Charter Infra- structure SM IDEAL is a service mark of Carnegie Mellon University. a) 由 IDEAL Model 轉入 CMMI-AM

© 2005 by Carnegie Mellon University CMMI Acquisition Module - Page M6-27 CMMI ® M6-Process Improvement v0.1 CMMI-AM Self-Assessment To guide the PM in assessing the acquisition program, the CMMI-AM includes a series of questions focused on: Acquisition Strategy Acquisition Planning Cost Schedule and Performance Baselines User Requirements Product Engineering Acquisition Processes Risk Identification and Management Questions are linked to the CMMI-AM Process Areas b) PM 自行依據 SEI’s questions 執 行 CMMI-AM Self- Assessment

© 2005 by Carnegie Mellon University CMMI Acquisition Module - Page M4-28 CMMI ® M4 – CMMI-AM and Support v0.1 Roles and Information Exchange Status Information Monitor & oversee progress Quality of tangibles Develop, customize, integrate Software Systems COTS PMO Contractor Directions, Corrections Deliverables Interim Documents, Tangibles Functional Requirements Pre-award activities Post-award activities RFP prep. Contract Award Sub- contractors c1) 強化 PM 與 Contractor 之間的 Information Exchange

© 2005 by Carnegie Mellon University CMMI Acquisition Module - Page M4-29 CMMI ® M4 – CMMI-AM and Support v0.1 Evaluate Quality of Deliverables PMO’s Inspection or Review Process Measurable Results (Examples) Products defects discovered –description, severity, class, type size of the work product Process effort invested in the inspection process time spent during the inspection activities PMO’s Evaluation Criteria Documents to review SRD SDP Meas Plan SDD Etc. Indicators Final Deliverables c2) 強化 PM 與 Contractor 之間的 Products Evaluation & Measurement

© 2005 by Carnegie Mellon University CMMI Acquisition Module - Page M4-30 CMMI ® M4 – CMMI-AM and Support v0.1 Monitor and Oversee PMO’s Analysis & Review Process Measurable Results (Examples) contractor effort actual vs. plan contractor schedule actual vs. plan defects reported description, severity, class, type size, complexity of the work product Status Information schedule progress budget status test results process results, e.g. inspections Process compliance etc. Indicators PMO's Evaluation Criteria c3) 強化 PM 與 Contractor 之間的 Schedule/Cost Evaluation & Measurement

© 2005 by Carnegie Mellon University CMMI Acquisition Module - Page M3-31 CMMI ® CMMI-AM and Engineering v0.1 Requirements and DoD Acquisition 2 Operational Need AoA JCIDS Users JROC ICD CDD PMO Supplier Requirements Development RFP, SOW, SOO, etc. User validation User input Analyze requirements Derive requirements Allocate requirements System Sub- systems Component Sub- systems Component d1) 強化需求工 程：找出 Needs

© 2005 by Carnegie Mellon University CMMI Acquisition Module - Page M3-32 CMMI ® CMMI-AM and Engineering v0.1 Overly simplistic elicitation Failure to identify / validate “root” of the requirement Lack of attention to stakeholder requirements Failure to involve all stakeholders Develop Customer Requirements Collect stakeholder needs Elicit needs Develop customer requirements Typical Work Products Customer requirements Customer constraints on the conduct of verification Customer constraints on the conduct of validation Sample Key Issues d2) 強化需求工程： 找出 Requirements

© 2005 by Carnegie Mellon University CMMI Acquisition Module - Page M3-33 CMMI ® CMMI-AM and Engineering v0.1 Requirements Must be Balanced Adapted from COTS- Based Systems for Program Managers Marketplace Stakeholder Needs / Business Processes Programmatics/ Risks Architecture / Design Simultaneous Definition & Tradeoffs d3) 強化需求工 程：找出平衡 點

© 2005 by Carnegie Mellon University CMMI Acquisition Module - Page M2-34 CMMI ® CMMI-AM and Project Management v0.1 Acquisition Method MethodReq’tsTechnologyScheduleCommentsExample Single StepAll known at start All Mature at start No need for early deployment Software requirements must also be stable New utility truck Evolutionary - Incremental All known at start Technology for first increment mature May be a need for early deployment Could have incremental software and single-step hardware Missile with improved range over 2-3 increments Evolutionary - Spiral Req’ts for first spiral known at start Technology for first spiral mature May be a need for early deployment Spirals may also be for risk reduction – not deployment A communi- cation system with new interfaces yet to be defined e1)EASD

© 2005 by Carnegie Mellon University CMMI Acquisition Module - Page M2-35 CMMI ® CMMI-AM and Project Management v0.1 Single-Step and Evolutionary Acquisition 100% Based on AF Program Manager Workshop presented by Mr Little Single-Step Time Known increment ‘Deliverable’ Capability 100% of requirements known at start Known increment Partially known increment Unknown increment Only first increment requirements known at start Incremental Spiral Known increment User, developer, tester, sustainer “use and learn” e2)EASD

© 2005 by Carnegie Mellon University CMMI Acquisition Module - Page M2-36 CMMI ® CMMI-AM and Project Management v0.1 Evolutionary Approach CR TDSDDPDOS B Increment 2 Increment 3 AC BC BC Increment 1 Adapted from dod5000.dau.mil = Contractor Spiral Development = Contractor Incremental Development e3)EASD

© 2005 by Carnegie Mellon University CMMI Acquisition Module - Page M2-37 CMMI ® CMMI-AM and Project Management v0.1 Evolutionary Approach (Space) Pre KDP-A Phase A Study Phase Phase B Design Phase Phase C (Build, Test Launch) B Increment 2 Increment 3 AC BC BC Increment 1 Adapted from NSS and dod5000.dau.mil = Contractor Spiral Development = Contractor Incremental Development e4)EASD

© 2005 by Carnegie Mellon University CMMI Acquisition Module - Page M2-38 CMMI ® CMMI-AM and Project Management v0.1 Acquisition & Development Methods = fielded system Acquisition of a New Utility truck Single Step Acquisition, Contractor Incremental Development Increment 1 – Hard to produce brakes Increment 2 – Easier to produce brakes Inc 3 – Develop new interfaces Spiral 1 – Prototype 1 Spiral 2 – Prototype 2 Spiral 3 – Prototype 3 Inc 2–SW radios for existing interfaces Increment 1- Interface 1 Increment 2- Interface 2 Inc 1 – HW Upgrades Single Step Development Evolutionary Acquisition (Spiral), Contractor Mixed Development – Comms System e5)EASD

39 AFSPC- SMC “Customer-Supplier” KeyDecisionPoints: Draft USECAF Space Acq Policy 02-1 Pre-AcquisitionApproval PHASE B Pre-Acquisition Sys Def & Risk Reduction Acquisition & Operations Approval PHASE A Concept Definition Studies ConceptDefinitionApproval PHASE C Acquisitions and Operations C B A SRRSDRPDRCDR 1st Launch Pre-Systems Acquisition Systems Acquisition Sustainment & Disposal EVOLUTIONARY REQUIREMENTS DEFINITIONS NEED ANALYSIS SUPPORT TECHNOLOGY OPPORTUNITY ALTERNATIVE CONCEPTS REDUCED RISK ALTERNATIVES DETAILED DESIGN PRODUCTION & REFINED FINAL DESIGN PRODUCT IMPROVEMENT MNSMNS ORD1ORD1 ORD2ORD2 PPBS Phase A Phase B Phase C APPROVAL AS REQUIRED MODREQMODREQ Responsibility of AF/DoD/AFSPC Responsibility of SMC and any contractor

40 E. 國內之可行方式 a) 由系統工程檢視軟體採購之需求定義程序 b) 由 IEEE 之 Acquisition process 進行程序 書規劃 c) 建立 CM 、 V&V 、 Performance Monitor 、 Review/Audit 、 Risk Management 之專業工程 d) 以 Products 角度建立 Program WBS e) 由 WBS 撰述 RFP 架構 f) 需求不明確之計畫應採用 Evolutional Acquisition – Spiral Development model g) 新開發需求軟體專案應採用成本計價 (Costing)

Slide System/Subsystem Design Description (SSDD) System Specification (SS) (MIL-STD-961D) Requirements Requirement: “Noun shall verb.” Example: The car shall stop within 100 feet at 50 mph. Functional Performance Function: “Verb Noun.” Example: Stop Car or “Verb-ing.” Example: Stopping. Component: “Noun.” Example: Brake. Functions Components System/Subsystem Specification (SSS) System Requirements Document (SRD) System Requirements Specification (SRS) (SSDD/SS) What is Systems Engineering? (cont) JOC Key Terms and Relationships 由系統工程檢 視軟體採購之 需求定義程序

42 由 IEEE 之 Acquisition process 進行程序 書規劃

WBS/ 43/9180 “Family tree“ 是一種圖示表達方 式，輔助讀者易於了解下層 Components 如何組成上層 Components 。 “Major Element”, or “Prime Mission Equipment”, or “Prime Mission Product” Common WBS Elements Aircraft Systems Work Breakdown Structure 範例 Aircraft System Air Vehicle Training Peculiar Support Equipment System T&E Sys Eng./ Program Mgmt Data Opn'l/Site Activation Common Support Equipment Industrial Facilities Initial Spares & Repair Parts Level 1 (Program Level) Level 2 (Project Level) Equipment Services Facilities DT&E OT&E Mockups T&E Support Test Facilities Construction/ Conversion/ Expansion Equipment Acquisition or Mod Maintenance Level 3 (System Level) Airframe Propulsion Application Software System Software Comm's/Identification Navigation/Guidance Central Computer Fire Control Data Display & Controls Survivability Reconnaissance Automatic Flight Control Central Integrated Checkout Antisubmarine Warfare Armament Weapons Delivery Auxiliary Equipment Test & Measurement Equipment Support & Handling Equipment Tech Pubs Eng Data Support Data Management Data Depository Test & Measurement Equipment Support & Handling Equipment Sys Assembly, Installation & Checkout on Site Contractor Tech Support Site Construction Site/Ship Vehicle Conversion “Major Program”

44 由 Requirements/WBS/SOW 轉換為專案之 IMP 以及 IMS

© 2005 by Carnegie Mellon University CMMI Acquisition Module - Page M2-45 CMMI ® CMMI-AM and Project Management v0.1 Acquisition Method MethodReq’tsTechnologyScheduleCommentsExample Single StepAll known at start All Mature at start No need for early deployment Software requirements must also be stable New utility truck Evolutionary - Incremental All known at start Technology for first increment mature May be a need for early deployment Could have incremental software and single-step hardware Missile with improved range over 2-3 increments Evolutionary - Spiral Req’ts for first spiral known at start Technology for first spiral mature May be a need for early deployment Spirals may also be for risk reduction – not deployment A communi- cation system with new interfaces yet to be defined 需求不明確者應選 用 Evolutionary- Spiral model