Chapter05 software project planning RPL
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Transcript of Chapter05 software project planning RPL
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8/10/2019 Chapter05 software project planning RPL
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These courseware materials are to be used in conjunction with Software Engineering: A Practitioners Approach,5/e and areprovided with permission by R.S. Pressman & Associates, Inc., copyright 1996, 2001
Chapter 5Software Project Planning
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These courseware materials are to be used in conjunction with Software Engineering: A Practitioners Approach,5/e and areprovided with permission by R.S. Pressman & Associates, Inc., copyright 1996, 2001
Software Project Planning
The overall goal of project planning is
to establish a pragmatic strategy forcontrolling, tracking, and monitoring acomplex technical project.
Why?
So the end resu l t gets don e on t ime,
w i th qual i ty!
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These courseware materials are to be used in conjunction with Software Engineering: A Practitioners Approach,5/e and areprovided with permission by R.S. Pressman & Associates, Inc., copyright 1996, 2001
The Steps
Scopingunderstand the problem and
the work that must be doneEstimationhow much effort? how
much time?
Riskwhat can go wrong? how can we
avoid it? what can we do about it?Schedulehow do we allocate
resources along the timeline? what arethe milestones?
Control strategyhow do we controlquality? how do we control change?
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These courseware materials are to be used in conjunction with Software Engineering: A Practitioners Approach,5/e and areprovided with permission by R.S. Pressman & Associates, Inc., copyright 1996, 2001
Write it Down!
SoftwareProject
Plan
Project ScopeEstimatesRisks
ScheduleControl strategy
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These courseware materials are to be used in conjunction with Software Engineering: A Practitioners Approach,5/e and areprovided with permission by R.S. Pressman & Associates, Inc., copyright 1996, 2001
To Understand Scope ...
Understand the customers needs
understand the business context
understand the project boundaries
understand the customers motivation
understand the likely paths for change
understand that ...
Even when you understand,
no th ing is guaranteed!
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These courseware materials are to be used in conjunction with Software Engineering: A Practitioners Approach,5/e and areprovided with permission by R.S. Pressman & Associates, Inc., copyright 1996, 2001
Cost Estimation
project scope must be explicitlydefinedtask and/or functionaldecomposition is necessaryhistorical measures (metrics) arevery helpful
at least two different techniquesshould be usedremember that uncertainty isinherent
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These courseware materials are to be used in conjunction with Software Engineering: A Practitioners Approach,5/e and areprovided with permission by R.S. Pressman & Associates, Inc., copyright 1996, 2001
Estimation Techniques
past (similar) project experience
conventional estimation techniques task breakdown and effort estimates
size (e.g., FP) estimates
tools (e.g., Checkpoint)
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These courseware materials are to be used in conjunction with Software Engineering: A Practitioners Approach,5/e and areprovided with permission by R.S. Pressman & Associates, Inc., copyright 1996, 2001
Functional Decomposition
Statementof Scope
performa
"grammatical
parse"
functionaldecomposition
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These courseware materials are to be used in conjunction with Software Engineering: A Practitioners Approach,5/e and areprovided with permission by R.S. Pressman & Associates, Inc., copyright 1996, 2001
Creating a Task Matrix
Obtained from process framework
application
functions
framework activities
Effort required toaccomplisheach frameworkactivity for eachapplication function
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These courseware materials are to be used in conjunction with Software Engineering: A Practitioners Approach,5/e and areprovided with permission by R.S. Pressman & Associates, Inc., copyright 1996, 2001
Conventional Methods:LOC/FP Approach
compute LOC/FP using estimates ofinformation domain values
use historical effort for the project
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These courseware materials are to be used in conjunction with Software Engineering: A Practitioners Approach,5/e and areprovided with permission by R.S. Pressman & Associates, Inc., copyright 1996, 2001
Example: LOC Approach
Functions
UICF
2DGA
3DGA
DSM
CGDF
PCF
DAM
Totals
estimated LOC $/LOC Cost Effort (months)LOC/pm
2340
5380
6800
3350
4950
2140
8400
33,360
14
20
20
18
22
28
18
315
220
220
240
200
140
300
32,000
107,000
136,000
60,000
109,000
60,000
151,000
655,000
7.4
24.4
30.9
13.9
24.7
15.2
28.0
145.0
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These courseware materials are to be used in conjunction with Software Engineering: A Practitioners Approach,5/e and areprovided with permission by R.S. Pressman & Associates, Inc., copyright 1996, 2001
Example: FP Approach
number of user inputs
number of user outputs
number of user inquiries
number of files
number of ext.interfaces
algorithms
measurement parameter
4
5
4
7
7
3
count
x
x
x
x
x
x
count-total
=
=
=
=
=
=
weight
complexity multiplier
feature points
0.25 p-m / FP = 120 p-m
40
25
12
4
4
60
160
125
48
28
28
180
569
.84
478
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These courseware materials are to be used in conjunction with Software Engineering: A Practitioners Approach,5/e and areprovided with permission by R.S. Pressman & Associates, Inc., copyright 1996, 2001
Tool-Based Estimation
project characteristics
calibration factors
LOC/FP data
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These courseware materials are to be used in conjunction with Software Engineering: A Practitioners Approach,5/e and areprovided with permission by R.S. Pressman & Associates, Inc., copyright 1996, 2001
Empirical Estimation Models
General form:
effort = tuning coefficient * sizeexponent
usually derivedas person-monthsof effort required
either a constant ora number derived based
on complexity of project
usually LOC butmay also befunction point
empiricallyderived
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These courseware materials are to be used in conjunction with Software Engineering: A Practitioners Approach,5/e and areprovided with permission by R.S. Pressman & Associates, Inc., copyright 1996, 2001
Estimation Guidelines
estimate using at least two techniques
get estimates from independent sources
avoid over-optimism, assume difficulties
you've arrived at an estimate, sleep on it
adjust for the people who'll be doing thejobthey have the highest impact
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These courseware materials are to be used in conjunction with Software Engineering: A Practitioners Approach,5/e and areprovided with permission by R.S. Pressman & Associates, Inc., copyright 1996, 2001
The Make-Buy Decision
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These courseware materials are to be used in conjunction with Software Engineering: A Practitioners Approach,5/e and areprovided with permission by R.S. Pressman & Associates, Inc., copyright 1996, 2001
Computing Expected Cost
(path probability) x (estimated path cost)i i
For example, the expected cost to b ui ld is:
expected cost = 0.30($380K)+0.70($450K)
simi lar ly,
expected cost = $382K
expected cost = $267K
expected cost = $410K
build
reuse
buy
contr
expected cost =
= $429 K