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CS 562 Advanced SW Engineering

CS 562 Advanced SW Engineering. Lecture #3 Tuesday, April 27, 2004. Class Format for Today. Turn in Paper #1 Questions Lecture #3: Chapter 2 – Model Definition Exercise?. Questions?. From last week’s class From the reading About the papers/project? Anything else?

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CS 562 Advanced SW Engineering

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  1. CS 562Advanced SW Engineering Lecture #3 Tuesday, April 27, 2004 CS 562 - WPI

  2. Class Format for Today • Turn in Paper #1 • Questions • Lecture #3: • Chapter 2 – Model Definition • Exercise? CS 562 - WPI

  3. Questions? • From last week’s class • From the reading • About the papers/project? • Anything else? • Everyone has books, all set with reading? CS 562 - WPI

  4. COCOMO IIModel Definition Boehm, et al Chapter 2 CS 562 - WPI

  5. Overview • Model Types • Post-Architecture Model • Early Design Model • How are these models defined? • Review Estimation Equations on page 13: • Amount of effort in Person-Months (Eq. 2.1) • Amount of calendar time (Eq. 2.2) • Review average-sized project example, p. 14 CS 562 - WPI

  6. Sizing • Types of size data used by COCOMO II: • New code • Reused code • Automatically translated code • How are the types of data treated differently? CS 562 - WPI

  7. Counting Source Lines of Code • Best source for estimating new lines of code is historical data. • What other options are given when lacking historical data? • Support software, such as test drivers: • Include/exclude? • When to estimate, why? • Use of SEI definition checklist (p. 16) CS 562 - WPI

  8. Unadjusted Function Points • How do function points measure a project? • Review user function types – Table 2.1, p. 17 • What other factors are considered? • 4-step procedure for determining UFPs • Steps listed on page 18 • Complexity levels & weights – Tables 2.2, 2.3 • Relating UFPs to SLOC • Conversion ratios in Table 2.4, p. 20 • What are USR slots used for? CS 562 - WPI

  9. Nonlinear Reuse Effects • Review Figure 2.2 & Equation 2.3, p. 21, and Figure 2.3, p. 22: • What are these about? • How & why are the effects nonlinear? • Discuss reuse penalties: • Software understanding • Module-interface checking CS 562 - WPI

  10. Reuse Model • Estimate amount of software to be adapted using 3 degree-of-modification factors: • Percentage of design modified • Percentage of code modified • Percentage of integration effort required • Review Equation 2.4, page 22 • How does this relate to Tables 2.5, 2.6, 2.7? • Also see ranges of reuse factors, Table 2.8, p. 26 CS 562 - WPI

  11. Req’s Evolution & Volatility • Adjust effective size of product caused by requirements evolution & volatility • What factors contribute to such volatility? • REVL = % of code discarded due to requirements evolution • Review example, bottom of p. 25 • How is this factor used to calculate size? • See Equation 2.5, p. 26 CS 562 - WPI

  12. Automatically Translated Code • Estimating costs of reengineering and conversion, using tools for restructuring • How do the tools impact the estimate factors? • Equation 2.6, p. 27, shows how auto translation affects estimated effort • What is AT? • What is ATPROD? • How are these factors calculated/estimated? CS 562 - WPI

  13. Sizing Software Maintenance • Scope of SW maintenance • Includes adding new capabilities & fixing or adapting existing capabilities • Excludes major product rebuilds and development of sizable interfacing systems • Review Equations 2.7 – 2.10, page 28 CS 562 - WPI

  14. Effort Estimation • Expressed in terms of person-months • How is PM defined? • How does this relate to TDEV? • Review Eq. 2.11, p. 29, and discuss inputs to this equation: • A, Size, E, Emi • How do cost drivers fit in – individual project components, vs. project as a whole? CS 562 - WPI

  15. Scale Factors • Economy vs. diseconomy of scale • What produces one or the other effect? • How does this impact effort estimation? • Review Eq. 2.12, p. 31, and Table 2.10, p. 32 • What are these about? • Discuss example on bottom of p. 31 • Review various scale factors in Sections 2.3.1.1 through 2.3.1.5 CS 562 - WPI

  16. Effort Multipliers • Used in Eq. 2.11, what are they? • Post-Architecture vs. Early Design EM’s • Post-Architecture: RELY, DATA, CPLX, RUSE, DOCU, TIME, STOR, PVOL, ACAP, PCAP, PCON, APEX, PLEX, LTEX, TOOL, SITE, SCED • Pages 41 – 51 • Early Design: RCPX, PDIF, PERS, PREX, FCIL • Pages 51 – 55 CS 562 - WPI

  17. Multiple Modules & Schedules • 6 steps for estimating multiple module effort • Why not just sum up individual module efforts? • Review steps listed on pages 55 – 57 • Schedule estimation – Eq. 2.14, p. 57 • Review factors that go into this equation • More info in Appendix A. CS 562 - WPI

  18. SW Maintenance & Decisions • How is SW Maintenance defined? • What assumptions are made? • Review Eq. 2.15 & 2.16, p. 59 • Section 2.6 presents an example for an auto-parts company named UST. • Discuss Sections 2.6.1 – 2.6.9, pgs. 60 – 68. • More examples (in 2 weeks) in Chapter 3. CS 562 - WPI

  19. For Next Time • Read Chapters 1-9 of Brooks • Come prepared to discuss • Proposal 1 for term project due CS 562 - WPI

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