5323896-cost-estimation-techniques.ppt

7/24/2019 5323896-cost-estimation-techniques.ppt

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BYBY ANU K LEKSHMY ANU K LEKSHMY

MCA III SEM MCA III SEM


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Estimating the cost of a Softwareproduct is one of the most dicult

and error prone tasks. Cost estimates can be of two types:

1) Top down approach

) !ottom up approach


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TOP DOWN APPROACH

"t focuses on system le#el cost likecomputing resources as well as the

cost of con$guration management%&uality assurance %system

integration %training and publications.

"t focuses on system le#el cost butmay o#erlook #arious technicalfactors.


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BOTTOM UP APPROACH

"t $rst estimates the cost to de#elopeach module and these cost are

combined to arri#e at an o#erallestimate.

"t emphasi'es the cost associated withde#eloping indi#idual system

components but fail to account forsystem le#el costs.


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METHODS FOR ESTIMATION

1) E(pert udgment

) *elphi Cost Estimation

+) ,ork !reakdown Structures

-) lgorithmic Cost /odels


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Compute the estimate cost of thesoftware system as the sum of

costs of the modules and thesubsystem that comprises the

system.

They follow !ottom 0p pproach.


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CONSTRUCTIVE COST MODEL


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This is one of the most widely used anddiscussed software cost estimation in the

industry.

"t has e#ol#ed into a more comprehensi#eestimation model called C2C2/2 "".

"n the COCOMO model EfortMultipliersare used to ad3ust the

estimate for product attribute %computerattribute %personal attribute and pro3ect

attribute.


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The following acti#ities are co#eredby the estimates:

a) Co#ers estimate throughacceptance testing

b) "ncludes the cost of

documentation and re#iews. c) "ncludes the cost of 4ro3ect

/anager.


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The cost estimators e(clude planning and

analysis costs %installation and training cost

and cost of computer operators %secretaries.

The *S" 5*eli#ered Source "nstruction)estimate includes 3ob control statement and

source statements but e(cludes comments "t is considered to be one line or card

image.


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Following are the assumptions estimated by the

COCOMO concerning the nature of the software:-

1) Careful de$nition and #alidation ofre&uirements is performed by a small

number of capable people.) 6e&uirements remain stable

throughout the pro3ect

+) Careful de$nition and #alidation ofarchitectural designs is performed by

a small number of capable people.


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-) *etailed design %coding and unittesting are performed in parallel by

group of programmers working inteams.

7) "ntegration Testing is based on

early test planning.8) "nterface errors are found by unit

testing and by inspections.


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9ormally there are mainly 1 steps toestimate the cost using C2C2/2:;

1) Identiy all the subsystem andmodules in the product.

2) Estimate the size o each moduleand calculate the size o each subsystem

and the total system.


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+) Specify the module levelmultipliers.

-) Compute the module e


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=) 9rom Step 8 compute the total systeme) 4erform sensiti#ity analysis on theestimate.

?) dd other de#elopment cost likeplanning and analysis that are not included

in the estimates.

1) Compare this estimate with the onede#eloped by *elphi estimation ."dentify

and 6ectify the di


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MODULE LEVEL MULTIPLIERS

4roduct Comple(ity

4rogrammers Capability

@irtual /achine E(perience

4rogramming Aanguage E(perience


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EFFORT MULTIPLIERS

4E6S2BA TT6"!0TESnalyst capability

4rogrammer capability

pplication e(perience@irtual machine e(perience4rogramming language

e(perience

462ECT TT6"!0TES0se of modern programming

practices0se of software tools

6e&uired schedule


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PRODUCT ATTRIBUTES

Required ReliabilityData-base Size

Product CompleityCO!PUTER ATTRIBUTES

Eecutio" time co"strai"t!ai" stora#e Co"strai"t$irtual mac%i"e reality

Computer tur"arou"dtime


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ADVANTAGES:-

oThe model can be used to gain insightinto the cost factors.

o Systematic techni&ues of softwareengineering are used throughout the

de#elopment process.

o*ata can be collected and analy'ed%new factors can be identi$ed and

e


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5323896-cost-estimation-techniques.ppt

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