BUS119A Lecture

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• BUS-119A Lecture 11 dbg SJSU 4/7/2006

• - Homework 2 is due today
• Effort to produce a Product i.e.. Staffing
• Complexity key the Number of interactions
• Effort by Project Phase (Design, Test, etc)
• Optimal Module size (for large products)
• Homework 3 assigned, due next week.

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• Effort over Time and Modularization

- Project Needs in resources (workforce)
first increase then decrease over time - Number
of people on a project peaks prior to shipping
the product - Module size needs to be limited
(complexity) - Complexity of interactions -
Interactions between people and teams -
Interactions between modules in a product




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• Complexity Depends on Number Of Items

Project with more people is more complex Product
with more modules is more complex
INTERACTION (I) OF N6 ITEMS
2
1
IN(N-1)/2 I65/215 I K N2
3
6
4
5
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• Six Items CENTRALIZED and HIERARCHICAL

CENTRALIZED HIERARCHICAL
One Manager Two Team Leaders
2
1
2
1
6
3
6
3
4
5
4
5
IN-1 I6-15 interactions
I12(N-1) I1225 interactions
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• Workforce profile Over Project Time

Putnam's formula SSpending per month or per
week (mostly cost of the workforce) D Time
when number of people on the project
reaches its peak (Sp) TsTime when the product is
ready to ship which is at time when S
falls to Sp/2 Te Time when product reaches "End
of Life" KTotal spending over life of the
project is equal to the area under the
curve S(Kt/D2)e(-t2/(2D2))
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K60, D6

• putnam.123 dbg 11/7/00

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(No Transcript)
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staffing.prz dbg 11/7/00

• Staffing over Time

Project needs 8 (PersonYears) effort. How
to estimate staff size by month
Rectangular Distribution
Rectangular Distribution
Rectangular Distribution
Triangular Distribution
of people working each month
of people working each month
of people working each month
of people working each month
16
16
8
8
8
8
8
12
12
12
6
12
12
time in months
time in months
time in months
time in months
time in months
time in months
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• Effort Distribution by Product Phase

Approximate ratio of Phase Cost to Cumulative
cost to ship time (varies by project and by
experience of the team)

• - Requirements 8 8
• - Fn. Spec 6 14
• - Logic 6 20
• - Module design 12 32
• - Coding 13 45
• - Unit Testing 13 58
• - Function Test 24 82
• - System Test 12 94
• User Documentation 6 100
• Total effort on project100

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• Optimal Module Size - Tradeoff between
• - Intramodule Complexity and
• - Intermodule Complexity

- Small modules (50 LOC) result in a large
number of modules (for a large product).
- Large modules (1000 LOC) result in a hard to
understand module and to maintain (service) it. -
Optimum is around 200 LOC/Module Example A
product estimated to be 50 KLOC 50,000 LOC
should have around M50,000 LOC/200
LOC/Mod500/2 Mod250 modules.
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• Homework 3 due at next lecture

(a) In homework 2 you determined the size of
your product that is measured in LOC and then
you calculated the Effort (in PersonMonths or
PY) that is needed to develop the product.
Now we learned that the workforce increases and
then decreases over project time (use
triangular distribution). Determine (a1) what
will be the the peak number of employees on
the project and (a2) At what time from the
beginning of the project is that peak
reached? (b) How many modules will have to be
written if we use the optimal module size
stated in the lecture? (c) Assuming effort
distribution over phases as stated in the
lecture, how much effort i.e (how many
PersonMonths) would be needed for Coding
your product?
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• Example of Estimation for Software Projects

If a product size is estimated at 12,300 LOC
and Productivity is 2KLOC/PY then the effort is
E(12.3 KLOC)/(2KLOC/PY)6.1 PY If the project
needs to be completed in 6 months, then we need
12.3 people working on it for 6 mo. Assuming
triangular workforce distribution we need a peak
workforce of 24.625 people at the time 3 months
from the start of the project. Number of modules
is 12.3KLOC/.2KLOC/Mod 61.5 Mod62
Modules. The effort for coding is .136.1
PY.79 PY or .79 PY 12 Mo/Yr 9.48 PM
or about 10 PM.
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• Factors used in grading HW3

• HW3 (Total 40 points)
• Any of 3 parts final result wrong up to -10
  points.
• Extraneous or wrong up to -3 points.
• Not rounding up/down like of modules or of
  persons to -3 pts.
• PY without PM loss of 6 points.
• Any missing unit -3 points
• A day late (after 3PM) -10
• Multiply instead of divide (arithmetic errors)
  -3 points.
• Calculation not shown, every missing statement
  -3 points.
• Peak staff (Max number of employees) (3 vs. 6
  months) -3 points.
• Other as encountered.

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• Product Abilities Function and Quality are the
  key

Acceptability - Interest and need of customers to
get a product and use it. Adaptability - Change
in one component does not require extensive
changes in others. Applicability - Match between
functional claims that product offers and
customer needs. Assistability - Degree to which a
product helps customers in doing certain
tasks. Availability - Percent of time that a
product is able to run out of all required
time Capability - Functionality or Ability
(FUNCTION) This is the key ability Feasibility -
Likelihood of achieving objectives (or
requirements) Flexibility - System's ability to
adapt to changing requirements. Functionality -
Systems scope of functions it can perform (ex.
Sort, Print etc.) Installability - How easy it is
to install the product Interoperability - Ability
of the different HW and SW to work in
unison Maintainability - Ability to modify,
understand and test when changes are
needed. Modularity - Product built in a way where
change in one module has minimal impact on
others. Performance - Primarily speed of transfer
or processing. It may mean all
"abilities". Reliability - Time or frequency that
the system or program failing (QUALITY) Reusabili
ty - Ability of products to be used in new
systems or with heavy modifications. Portability
- Ability of a product to run on different
hardware and different operating
systems Profitability - Ratio of
(Revenue-Cost)/Cost Serviceability - Ease of
repair. Depends on built in debugging facilities
and documentation. Usability - Nature of the
product where user can easily install, learn and
use the product. Upgradeability - Ease of adding
an increase in a resource. Example going from 1
GBY to 2 GBY. Viability Likelihood of making
the product a success A special Trio popular
in industry RAS Reliability, Availability,
and Serviceability --- end of Lecture 11 ---