How Information Systems Work

7.10. Tables  7.6 ,  7.9 , and  7.10 include  “ number of defects by category and severity level” for requirements, architectural design, and implementation, respectively.

  1. List three different categories of defects for requirements.
    1. List three different categories of defects for architectural design.
    1. List three different categories of defects for implementation.

7.13. Select a program of your choosing (or a program chosen by your  instructor).

  1. Construct a control fl ow graph for one of the modules in the program.
    1. Calculate the cyclomatic complexity number for one of the modules in the program.
    1. Construct the design fl ow graph for the program.
    1. Calculate the design complexity of the program.
    1. Assess and assign a value of Very Low, Low, Nominal, High, or Very High to each of the fi ve complexity factors used to determine CPLX in a COCOMO II model for the program. Briefl y explain why you chose the values you assigned to each of the fi ve factors. ( Hint:  See Table II- 1 5, page 31, at f tp://ftp. usc.edu/pub/soft_engineering/COCOMOII/cocomo99.0/modelman.pdf .)
    1. Assess and assign a value of Low, Medium, or High to the cohesion of each module in the program. Briefl y explain why you chose your assigned values.
    1. Assess and assign a value of Low, Medium, or High to the coupling of each module in the program. Briefl y explain why you chose your assigned values.

7.14. A system having an MTTF of 80 hours with as standard deviation of 2 hours would probably be rated higher in reliability than a system having an MTTF of 80 hours and a standard deviation of 40 hours. Briefl y explain why this would be true.

T ABLE 7.6      Some product measures for requirements activities

  • Number of requirements baselined versus number planned during this reporting period and cumulatively
  • Number of use cases developed versus number planned during this reporting period and cumulatively
  • Number of use cases reviewed and accepted as adequate during this reporting period and cumulatively
  • Number of requirements -b ased test cases and test scenarios generated versus number planned during this reporting period and cumulatively
  • Number of prototypes developed and reviewed versus number planned during this reporting period and cumulatively
  • Number of   * C Rs and   * D Rs for baselined requirements submitted, number accepted, number rejected, and number deferred during this reporting period and cumulatively
  • Number of requirements defects by defect category and severity level
  • Number of CRs and DRs for baselined requirements completed and closed during this reporting period and cumulatively
  • Number of CRs and DRs for requirements still open from this reporting period and from previous reporting periods
  • Amount of time required to close each CR and DR for baselined requirements
  • Status of traceability matrices (see Table  3.6 in Section  3.4.4)  ° from operational requirements to technical specifi cations

 ° from technical specifi cations to test cases and test scenarios

T ABLE 7.9     Some product measures for architectural design

  • Updates to requirements   *  CRs,   *  DRs, and other requirements status indicators
  • Number of design elements in the architectural design baseline versus number planned in this reporting period and cumulatively
  • Number of quality-  attribute scenarios prepared versus number planned in this reporting period and cumulatively
  • Number of quality-  attribute scenario walkthroughs and reviews versus number of planned in this reporting period and cumulatively
  • Number of design-  based test cases generated versus number planned in this reporting period and cumulatively
  • Number of design -b aseline CRs and DRs submitted, number accepted, number rejected, and number deferred during this reporting period and cumulatively
  • Number of design defects by defect category and severity level
  • Number of design -b aseline CRs and DRs completed and closed during this reporting period and cumulatively
  • Number of design -b aseline CRs and DRs still open from this reporting period and from previous reporting periods
  • Amount of time required to close design –b aseline CRs and DRs
  • Status of traceability matrices

 ° Requirements to design components

 ° Components to test cases

T ABLE 7.10      Some product measures for software implementation

  • Updates to requirements   * C Rs and   *  DRs, architectural design CRs and DRs, and other requirements and design status indicators
  • Number of modules baselined versus number planned in this reporting period and cumulatively
  • Complexity measures for modules, components, subsystems, and system
  • Number of code inspections conducted versus number planned during this reporting period and cumulatively
  • Number of code-  baseline CRs and DRs submitted, number accepted, number rejected, and number deferred during this reporting period and cumulatively
  • Number of code-  baseline CRs and DRs completed and closed during this reporting period and cumulatively
  • Number of code-  baseline CRs and DRs still open from this reporting period and from previous reporting periods
  • Amount of time required to close code -b aseline CRs and DRs
  • Cumulative density of discovered defects by defect category and severity level, based on total defects and total lines of baselined code
  • Forecast for completion of detailed design, coding and developer testing
  • Status of traceability matrices:

 ° from baselined modules and components to architecture

 ° from test cases specifi ed to modules and components

 ° from test cases successfully completed to modules and components

  • Using the formulas in Table  8.9 , develop a spreadsheet program to compute the following factors for a software project:

Cost variance (CV)

Schedule variance (SV)

Cost performance index (CPI)

Schedule performance index (SPI)

Estimated actual cost (EAC)

Estimated completion date (ECD)

Cost variance at completion (CVC)

Schedule variance at completion (SVC)

  • Apply the spreadsheet program developed in Exercise 8.9 to compute the values listed in the exercise.
  • Use the following set of data: BCWP = $ 40K, ACWP = $ 50K, and BCWS = $ 60K. Assume that BAC = $ 200K, SCD = 12 months, and that the project is at the end of the third month of a 12 -m onth schedule.
  • Verify the correctness of your spreadsheet by performing the calculations by hand; show your work.

TABLE 8.9      Earned value terminology

Term Defi nition Explanation
BCWP Budgeted Cost of Work Performed Cumulative amount of the budget for all tasks completed to date (i.e., the earned value)
ACWP Actual Cost of Work Performed Actual cost of all tasks completed to date
BCWS Budgeted Cost of Work Scheduled Planned cost of all tasks scheduled for completion to date
BAC Budget Actual Cost Planned cost of the total project
SCD Scheduled Completion Date Planned completion date of the project
EAC Estimated Actual Cost Estimated actual cost of the project based on progress to date
ECD Estimated Completion Date Estimated completion date based on progress to date
CV Cost Variance CV = ACWP – BCWP
SV Schedule Variance SV = BCWS – BCWP
CPI Cost Performance Index CPI = ACWP / BCWP
SPI Schedule Performance Index SPI = BCWS / BCWP
CVC Cost Variance at Completion CVC = EAC – BAC
SVC Schedule Variance at Completion SVC = ECD – SCD
  where EAC = BAC * CPI and ECD  = SCD * SPI

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