COCOMO II: Airborne Radar System Example

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COCOMO II Airborne Radar System Example
Dr. Ray Madachy madachy_at_usc.edu CSCI 510
October 2, 2002
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Outline

• Overview the Airborne Radar System (ARS)
• Demonstrate progressive usage of different COCOMO
  sub-models within an evolutionary spiral
  development process
• Cover estimation of reuse, modification, COTS,
  and automated translation
• Show how an aggregate estimate is refined in
  greater detail

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ARS Estimation

• Use Applications Composition, Early Design and
  Post-Architecture submodels
• Two Post-Architecture estimates are demonstrated
  top-level and detailed
• scale drivers apply to overall system in both
  estimates
• cost drivers are rated for the aggregate system
  in the top-level estimate (17 ratings)
• cost drivers are refined for each individual
  software component in the detailed estimate (176
  components102 ratings)

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ARS System Overview
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Software Components

• Radar Unit Control
• controls radar hardware
• Radar Item Processing
• extracts information from returned radar to
  identify objects
• Radar Database
• maintains radar object tracking data
• Display Manager
• high level displays management
• Display Console
• user input device interface and primitive graphic
  processing
• Built In Test
• hardware monitoring and fault localization

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COCOMO Coverage in Evolutionary Lifecycle Process
both top-level and detailed estimates shown
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Prototype Size and Effort
Productivity is high at 25 NAP/PM Effort
NAP/ Productivity 136.3/25 5.45 PM (or 23.6
person-weeks) Personnel 23.5 person-weeks/6
weeks 4 full-time personnel
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Scale Factors for Breadboard
Factor Rating

• Precedentedness (PREC)
• Development Flexibility (FLEX)
• Risk/Architecture Resolution (RESL)
• Team Cohesion (TEAM)
• Process Maturity (PMAT)

• Nominal
• Low
• High
• Nominal
• Nominal

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Early Design Cost Drivers for Breadboard
Factor Rating

• High
• Very High
• High
• High
• Nominal
• Nominal
• Nominal

• Product Reliability and Complexity (RCPX)
• Required Reuse (RUSE)
• Platform Difficulty (PDIF)
• Personnel Capability (PERS)
• Personnel Experience (PREX)
• Facilities (FCIL)
• Schedule (SCED)

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Breadboard System Size Calculations
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Early Design Estimate for Breadboard
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ARS Full Development for IOC

• Use Post-Architecture estimation model
• same general techniques as the Early Design model
  for the Breadboard system, except for elaborated
  cost drivers
• Two estimates are demonstrated top-level and
  detailed
• scale drivers apply to overall system in both
  estimates
• cost drivers are rated for the aggregrate system
  in the top-level estimate (17 ratings)
• cost drivers are refined for each individual
  software component in the detailed estimate (176
  components102 ratings)

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ARS Top-Level Size Calculations
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Post-Architecture Estimate for IOC (Top-level)
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Post-Architecture Estimate for IOC (Detailed)
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Sample Incremental Estimate
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Increment Phasing
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Increment Summary
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Summary and Conclusions

• We provided an overview of the ARS example
  provided in Chapter 3
• We demonstrated using the COCOMO sub-models for
  differing lifecycle phases and levels of detail
• the estimation model was matched to the known
  level of detail
• We showed increasing the level of component
  detail in the Post-Architecture estimates
• Incremental development was briefly covered