Putnam Resource allocation model.ppt

Putnam Resource allocation model

1. Putnam Resource allocation model
•Putnamstudiedtheproblemofstaffingofsoftwareprojects
andfoundthatthesoftwaredevelopmenthascharacteristics
verysimilartootherR&DprojectsstudiedbyNordenand
thattheRayleigh-Nordencurvecanbeusedtorelatethe
numberofdeliveredlinesofcodetotheeffortandthetime
requiredtodeveloptheproject.
•analyzingalargenumberofarmyprojects,Putnamderived
thefollowingexpression:

2. Rayleigh manpower loading curve

3. •Kisthetotaleffortexpended(inPM)intheproduct
developmentandListheproductsizeinKLOC.
•tdcorrespondstothetimeofsystemandintegration
testing.Therefore,tdcanbeapproximately
consideredasthetimerequiredtodevelopthe
software.
•Ckisthestateoftechnologyconstantandreflects
constraintsthatimpedetheprogressofthe
programmer.

4. •TypicalvaluesofCk=2forpoordevelopmentenvironment
(nomethodology,poordocumentation,andreview,etc.),
•Ck=8forgoodsoftwaredevelopmentenvironment(software
engineeringprinciplesareadheredto),
•Ck=11foranexcellentenvironment(inadditiontofollowing
softwareengineeringprinciples,automatedtoolsand
techniquesareused).TheexactvalueofCkforaspecific
projectcanbecomputedfromthehistoricaldataofthe
organizationdevelopingit.

5. Forexample,iftheestimateddevelopmenttimeis1year,theninorderto
developtheproductin6months,thetotaleffortrequiredtodevelopthe
product(andhencetheprojectcost)increases16times.

7. Basic COCOMO
•Basicmodelaimatestimating,inaquickandrough
fashion,mostofthesmalltomediumsizedsoftware
projects
•Thesemodelsofsoftwaredevelopmentare
consideredinthismodel:organic,semi-detected
andembedded
•KLOC(thousandsoflinesofcode)isatraditional
measureofhowlargeacomputerprogramisorhow
longorhowmanypeopleitwilltaketowriteit.

9. Organic:
Adevelopmentprojectcanbeconsideredoforganictype,if
theprojectdealswithdevelopingawellunderstood
applicationprogram,thesizeofthedevelopmentteamis
reasonablysmall,andtheteammembersareexperiencedin
developingsimilartypesofprojects.
Semidetached:
Adevelopmentprojectcanbeconsideredofsemidetached
type,ifthedevelopmentconsistsofamixtureofexperienced
andinexperiencedstaff.Teammembersmayhavelimited
experienceonrelatedsystemsbutmaybeunfamiliarwith
someaspectsofthesystembeingdeveloped.

10. Embedded:
Adevelopmentprojectisconsideredtobeof
embeddedtype,ifthesoftwarebeing
developedisstronglycoupledtocomplex
hardware,orifthestringentregulationson
theoperationalproceduresexist.

13. Basic COCOMO model
•ThebasicCOCOMOmodelgivesanapproximateestimateof
theprojectparameters.ThebasicCOCOMOestimationmodel
isgivenbythefollowingexpressions:

15. Example
•Aprojectsizeof200KLOCistobedeveloped.
Softwaredevelopmentteamhasaverage
experienceonsimilartypeofprojects.The
projectscheduleisnotverytight.Calculate
theeffort,developmenttime,averagestaff
sizeandproductivityoftheproject.

16. Solution

17. Example
•Assumethatthesizeofsoftwareprojecthas
beenestimatedtobe32,000linesofcode.
Determinetheeffortrequiredtodevelopthe
softwareproductandnominaldevelopment
time.

18. Example
•Supposethataprojectwasestimatedtobe
400KLOC.Calculatetheeffortand
developmenttimeforeachofthethree
modesi.e.,organic,semidetachedand
embedded.

20. Intermediate Model
•Basicmodelallowedforquickandroughestimate
butitresultedinlackofaccuracy
•SoBohemintroducedanadditionalsetof15
predictorscalledcostdriversinintermediatemodel
totakeaccountofthesoftwaredevelopment
environment
•Costdriversareusedtoadjustthenormalcostofthe
projecttotheactualprojectenvironment,hence
increasingtheaccuracyoftheestimate.
•Thesecostdriversgroupedintofourcategories:-

23. Multiplier values for effort calculations

24. Multiplier values for effort calculations

25. Coefficients for intermediate COCOMO

29. Detailed COCOMO Model
•Largeamountofworkhasbeendoneby
Bohemtocaptureallsignificantaspectsof
softwaredevelopment
•Itoffersameansforprocessingalltheproject
characteristicstoconstructsoftwareestimate.

30. COCOMO-II
•RevisedversionoftheoriginalCOCOMO
•Itprovidequantitativeanalyticframeworkand
setoftoolsandtechniquesforevaluatingthe
effectofsoftwaretechnologyimprovementon
softwaredevelopmentlifecyclecostand
schedule.