May 11, 2004CS WPI1 CS 562 Advanced SW Engineering Lecture #5 Tuesday, May 11, 2004

May 11, 2004CS WPI2 Class Format for Today Return Proposal #1 Turn in Paper #2 Questions Lecture #5: Chapter 3 – Application Examples

May 11, 2004CS WPI3 Questions? From last week’s class From the reading About the papers/project? Anything else?

May 11, 2004CS WPI4 COCOMO II Application Examples Boehm, et al Chapter 3

May 11, 2004CS WPI5 Overview 2 example systems: Transaction Processing System (TPS) Airborne Radar System (ARS) Show how to use COCOMO II to: Develop estimates Perform trade studies Justify purchase of SW tools Perform risk analysis, etc.

May 11, 2004CS WPI6 Transaction Processing System Client-server system designed to: Interactively process queries Perform a variety of functions across a network Types of transactions could include: Airline reservations, financial transactions Library searches, remote DB browsing, etc. TPS Software Capabilities: Review Table 3.1, page 85

May 11, 2004CS WPI7 SW Dev. Organization Experienced client-server programmers Process improvement efforts underway Issues: Technical 1 st -level management Language (C++ vs. Java) Optimistic / pessimistic estimates Lines of code vs. function points

May 11, 2004CS WPI8 Estimation Process Estimate effort for client-side software Review process illustrated in Figure 3.2, p. 88 Metrics Sizing figures in Table 3.2, p. 88 Work breakdown structure (WBS) Figure 3.3, p. 89 COCOMO Model scope Table 3.3, p. 90

May 11, 2004CS WPI9 Sizing System SW Component Need to distinguish between 4 categories: New, Modified, Reused, COTS Convert reused SW into equivalent new LOC Review formulas on pages 90 – 91 What is the bottom line estimate for the System component? Do the numbers make sense?

May 11, 2004CS WPI10 Sizing GUI Component What information is taken from table 3.2? What else needs to be considered? What is the bottom line estimate for this component? Do the numbers make sense?

May 11, 2004CS WPI11 Sizing Fault Diag. Component Start with estimate in Function Points How to convert to LOC? Initial estimate seems unreasonable How does one arrive at that conclusion? What needs to be done about it? What is the bottom line estimate for this component? Do the numbers make sense?

May 11, 2004CS WPI12 Estimate Effort using WBS 5 tasks outlined in Table 3.4, p. 93: Develop software requirements ( ) Develop software ( ) Perform task management ( ) Maintain configuration control ( ) Perform software quality assurance ( ) Review issues and considerations for each How are the numbers derived?

May 11, 2004CS WPI13 Develop COCOMO II Estimate Process is outlined in Figure 3.4, p. 96 What assumptions are made at the beginning? Table 3.5, p. 97 shows scale factor ratings Tables 3.6 – 3.9 show cost driver ratings What assumptions are present in the rationale? Do the assumptions seem reasonable? Why / why not? Review COCOMO output in Figures 3.5, 3.6, p. 101: nominal vs. schedule constrained

May 11, 2004CS WPI14 Compare Estimates What are the differences between WBS & COCOMO II estimates? Why are they different? Which one is correct? How to resolve differences What approach does the book take? Do you agree with the approach? Why create 2 different estimates?

May 11, 2004CS WPI15 Bounding Risk Table 3.10, page 104 shows “Top 10” high- risk areas for TPS How to evaluate & prioritize? Discuss the various risks: Review sections 1-10 on pages 103 – 107 Do the suggestions and approaches for handling risk make sense?

May 11, 2004CS WPI16 Trade Studies COTS Software, Language, and Paradigm: Review Tables 3.11 – 3.13, pages What approaches are taken for these studies? How do you interpret the results? Do you agree with the conclusions?

May 11, 2004CS WPI17 Assessing Life Cycle Costs Review formulas on page 113: How do they differ for maintenance as opposed to development? Review Table 3.15 (p. 114) & Figure 3.8 (115) What happens to cost/benefit analysis of COTS when life cycle is considered?

May 11, 2004CS WPI18 Airborne Radar System Complex, real-time embedded system Involves concurrent dev. of new hardware Upgrade to an existing system already in use Constructed using substantial reuse & automatic translation 3 COCOMO models: Application Composition, Early Design and Post-Architecture

May 11, 2004CS WPI19 ARS Description Hardware: Central on-board computer Radar & other sensor units Proprietary display console w/ input devices Trackball, programmable touch panel, function keys Software: See Figure 3.9, p. 117 & Table 3.16, p. 118

May 11, 2004CS WPI20 Prototype Analysis Estimated using Application Points: See Table 3.17, p. 119 and Table 3.18, p. 120 Learn more about Applications Composition model in Chapter 5 What variables are considered in cost estimate? See Formula on page 117 Do the numbers seem reasonable?

May 11, 2004CS WPI21 Early Design Model What is the “Breadboard System”? What can/cannot be considered at this stage? Review Scale Factors & Cost Drivers Table 3.19, p. 121 and Table 3.20, p. 122 Review Size calculations – Table 3.21, p. 123 What assumptions are made? What is the bottom line time estimate? Do the numbers make sense?

May 11, 2004CS WPI22 Full Development – Top Level Use Breadboard system for additional input Productivity of automatic translation Quantify sizes of objects in lines of code Historical data for ratings profile (Figure 3.11) New Scale Factors & Cost Drivers See Tables 3.22 and 3.23, page 128 New Size calculations for full ARS Dev. See Table 3.24, page 130 and Formulas, page 131

May 11, 2004CS WPI23 Detailed Component Estimates Scale factors remain the same, but detailed cost-driver ratings and rationale differ See tables 3.25 through 3.30 (pages 133, 134) From detail, get new estimated time/effort: See formulas on page 132 and 134 Review COCOMO output, Fig. 3.14, p. 135 How does the top-level estimate compare to the one with more detail?

May 11, 2004CS WPI24 Incremental Development 3 time-phased increments of individually delivered software builds Req’s & prelim design done first for all increments Impl contains some work done in parallel Need to decide what to deliver when See bullet list on p. 136, phased plan on pages Take increment volatility into account Review Figures pages

May 11, 2004CS WPI25 For Next Time Read Chapter 4 in Boehm, et al Proposal 2 for Paper 4 due