COCOMO Presentation

8/7/2019 COCOMO Presentation

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³COCOMO II : MODEL FOR ESTIMATINGSOFTWARE COST´

HONORS CREDIT

CONTRACT

Kapil B. Vyas





History

Boehm Barry± Designed COCOMO II

± BA degree from Harvard in 1957

± MS and PhD degrees from UCLA in 1961 and 1964

± Research Interests include:

software process modeling, software requirementsengineering, software architectures, software metrics and cost

models, software engineering environments, and knowledge-based software engineering

± Other contributions:

Spiral Model of the software process, the Theory W (win-win)approach



History

COCOMO II background± is a well known model used in software cost and schedule

estimation± research on software cost modeling began with the

extensive 1965 SDC study of the 104 attributes of 169software projects

± In the late 1970s, several sophisticated software costestimating models developed in response to the demand for

control of escalating software costs: RCA PRICE-S, SLIM± Barry employed by TRW developed a proprietary

algorithmic (or parametric) software cost model

± He wrote the book Software Engineering Economics, whichcompletely described and explained COCOMO.



Current Status

The USC CSSE overlooks the progress of COCOMO II

Their website at http://csse.usc.edu/csse boasts around 42 industry

and government affiliates Their affiliates include Cisco, Boeing, IBM, Samsung, Microsoft,

General Dynamics, DARPA

They have courses wherein 5-student teams develop real-client e-service applications for campus (and some off-campus) organizations.

Events:± Upcoming 2009 CSSE-Annual Research Review at the USC Campus from

March 16 to 19± International Forum on COCOMO and Systems/Software Cost Modeling

on October 26 to 29 in Washington D.C.

Available Computerized Editions:± Costar, Cost Xpert, and Estimate Professional.



Architectural Overview

Three main models:

± Applications Composition

± Early Design± Post-Architecture

Applications model rely on having an integrated computer-aided software engineering (ICASE) environment

Post-Architecture model is used once the architecture of the

system is well defined Early Design model is a high level model that is used in the

exploration of architectural alternatives or incrementaldevelopment strategies.



Early Design and Post Architecture model

Early Design model

± It uses Unadjusted Function Point (UFP) counts which are

converted to DSI.± Application adjustment factors are not applied until after

conversion to SLOC.

effort, PMNS = a x Size b x EMi (i = 1 to 6)

where a = 2.94 (calibrated from 161projects)

b = 1.01 + 0.01 x SFj (j = 1 to 5)

and EMi - effort multipliers for 6 different cost drivers

SFi - exponential scale factors for 5 cost drivers

NS - implies nominal schedule



Early Design and Post Architecture model

Post Architecture Model:

± This model is intended mainly for actual development activities.

± It is essentially a modern update to COCOMO 81.± It considers a wide range of drivers.

± New cost drivers include reusability, documentation needs,personnel continuity and multi-site teams.

effort, PMNS = a x Size b x EMi (i = 1 to 16)

where a = 2.94 (calibrated from 161 projects

b = 1.01 + 0.01 x SFj (j = 1 to 5)

and EMi - effort multipliers for 16 different cost driversSFi - exponential scale factors for 5 cost drivers

NS - implies nominal schedule



Significant Aspects of COCOMO II

Aspect Elaboration

Five exponential scale factors precedentedness, development flexibility,

architecture/risk resolution, team cohesion,

process maturity

Adaptation Adjustment Multiplier non-linear cost of assessment andassimilation, software understanding, and unfamiliarity

for reuse of software

Three sizing options application points, function points, source lines of code

Three levels of cost model granularity Application Composition, Early Design,

Post-ArchitectureThree development processes waterfall, MBASE, incremental

New cost drivers software reuse, required documentation, personnelcontinuity, and multiple development sites

Bayesian calibration historical data plus expert judgment



Conclusion and Future Work

Recent work on COCOMO methodology at the USC Center for Software Engineering has focused on developing extensions to

work to unify the various models into a single, comprehensiveestimation tool. new models based on COCOMO II

A COCOMO II extension is an estimation model that uses theoutput of COCOMO II and modifies it in various ways.

A new model is one based on the COCOMO approach to modelbuilding but which requires its separate inputs.

New models can be used in conjunction with COCOMO II if desired.

Information about COCOMO II extensions and new models canbe found on the web site for the USC Center for SoftwareEngineering.

Documents

COCOMO Presentation