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COSYSMO: Constructive Systems Engineering Cost Model

COSYSMO: Constructive Systems Engineering Cost Model. Barry Boehm, USC CSE Annual Research Review February 6, 2001. USC. University of Southern California. C. S. E. Center for Software. Engineering. Outline. Background Scope Proposed Approach Strawman Model Size & complexity

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COSYSMO: Constructive Systems Engineering Cost Model

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  1. COSYSMO: Constructive Systems Engineering Cost Model Barry Boehm, USC CSE Annual Research Review February 6, 2001

  2. USC University of Southern California C S E Center for Software Engineering Outline • Background • Scope • Proposed Approach • Strawman Model • Size & complexity • Cost & schedule drivers • Outputs • Issues ©USC-CSE

  3. Background • Topic of breakout group at October 2000 COCOMO/SCM Forum • Decided on incremental approach • Increment I: front-end costs of information systems engineering • Coordinating with development of INCOSE-FAA systems engineering maturity data repository • Also coordinating with Rational sizing metrics effort ©USC-CSE

  4. COSYSMO Increment I : Scope • Expand COCOMO II to information system engineering front end costs • Excluding aircraft, printer, etc. system engineering • sensors a gray area • Excluding Transition effort for now • All of Inception and Elaboration effort • Construction: Requirements; Deployment; 50% of Design effort ©USC-CSE

  5. Proposed System Engineering Scope: COCOMO II MBASE/RUP Phase and Activity Distribution ©USC-CSE

  6. Proposed Approach • Develop strawman model • First iteration internally • Second iteration today • Discuss Issues (see below) • Initial assessment of relative cost/schedule driver influence • Develop, experiment with revised model • Find appropriate Ph D student ©USC-CSE

  7. Strawman COSYSMO • Sizing model determines nominal COCOMO II SysE effort and schedule • Function points/use cases for basic effort • Tool and document preparation separate (?) • “source of effort” • Factor in volatility and reuse • Begin with linear effort scaling with size (?) • Cost & Schedule drivers multiplicatively adjust nominal effort and schedule by phase, source of effort (?) • Application factors • Team factors ©USC-CSE

  8. USC Strawman Sizing Model • Function points, adjusted for complexity • Use cases, adjusted for complexity • flows of events; complexity of interactions • Rqts. Volatility factor similar to COCOMO II • Reuse factor simpler than COCOMO II (TBD) • Weighting of FP, use case quantities TBD • Also use pairwise comparison approach for sizing • Compare with known systems • Use COCOMO II CPLX factors for complexity (?) • Control, computability, device-dependent, data management, UI operations scales ©USC-CSE

  9. Evolving Rational Sizing Model • Objective: Obtain “software mass” for COCOMO engine • USC “MVC” approach • “Model” -- number of classes of data • “View” -- number of use cases • “Control” -- distribution and algorithm complexity • Size new application by MVC comparison to similar applications • Overall, very similar to USC strawman sizing approach • Preparing to collaboratevia Philippe Kruchten ©USC-CSE

  10. Cost & Schedule Drivers: Application Factors • Requirements understanding • Architecture understanding • Level of service rqts. criticality, difficulty • External interface complexity • Legacy transition complexity • COTS assessment complexity (COCOTS-overlap?) • Platform difficulty (PDIF - Early Design) • Required business process reengineering ©USC-CSE

  11. Cost & Schedule Drivers : Team Factors • # of stakeholder communities • Average TEAM rating (COCOMO II scale factor) • Heterogeneity (domains, cultures) • Personnel capability/continuity (PERS-Early Design) • Personnel experience (PREX-Early Design) • Process maturity (PMAT) • Multisite coordination (SITE) • Degree of system engineering ceremony • Tool support (modified TOOL scale) ©USC-CSE

  12. Strawman Model : Outputs • Effort & schedule by phase • By activity ? • By source of effort (analysis, prototypes, tools, documents)? • Risk assessment ? ©USC-CSE

  13. Issues : Suggestions on Improving • Scope • Proposed Approach • Model Form • Model Elements • Outputs • Over/underlaps with COCOMO II, COCOTS, CORADMO • Sources of data • Staffing ©USC-CSE

  14. COSYSMO: Factor Importance Rating Rate each factor H, M, or L depending on its relatively high, medium, or low influence on system engineering effort. Use an equal number of H’s, M’s, and L’s. Application Factors ______ Requirements understanding ______ Architecture understanding ______ Level of service rqts. criticality, difficulty ______ Legacy transition complexity ______ COTS assessment complexity ______ Platform difficulty ______ Required business process reengineering ______ TBD ______ TBD Team Factors ______ Number and diversity of stakeholder communities ______ Stakeholder team cohesion ______ Personnel capability/continuity ______ Personal experience ______ Process maturity ______ Multisite coordination ______ Degree of system engineering ceremony ______ Tool support ______ TBD ______ TBD ©USC-CSE

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