Slide INF205 RPL Pertemuan 2
REKAYASA PERANGKAT
LUNAK
PERTEMUAN 2
PERENCANAAN PROYEK
PERANGKAT LUNAK
Pendahuluan
• Software project management begins with a set of activities
that are called project planning.
• Before the project can begin, the manager and the software
team must estimate the work to be done, the resources that
will be required, and the time that will elapse from start to
finish.
• Whenever estimates are made, we look into the future and
accept some degree of uncertainty as a matter of course.
Pendahuluan
• Estimation begins with a description of the scope of the
product.
• The problem is then decomposed into a set of smaller
problems and each of these is estimated using historical
data and experience as guides.
• It is advisable to generate your estimates using at least two
different methods (as a cross check).
• Problem complexity and risk are considered before a final
estimate is made.
Tujuan Perencanaan PPL
To provide a framework that enables the manager to
make reasonable estimates of resources, cost, and
schedule.
Scope (Ruang Lingkup) PL
• The first activity in software project planning is the
determination of software scope.
• Unambiguous and understandable at the management and
technical levels.
• A statement of software scope must be bounded.
• Software scope describes the data and control to be
processed, function, performance, constraints, interfaces,
and reliability.
Mendapatkan Ruang Lingkup
• Conduct a preliminary meeting or interview.
• Example questions:
•
•
•
•
Who is behind the request for this work?
Who will use the solution?
What will be the economic benefit of a successful solution?
Is there another source for the solution?
Feasibility (Kelayakan)
• Scoping is not enough.
• “Can we build software to meet this scope? Is the project
feasible?”
• Four solid dimensions:
• Technology — Is it within the state of the art?
• Finance — Can development be completed at a cost the software
organization, its client, or the market can afford?
• Time — Will the project’s time-to-market beat the competition?
• Resources — Does the organization have the resources needed to
succeed?
Resources (Sumber Daya)
Perspektif Sumber Daya
• Masing-masing sumber daya tersebut dispesifikasikan
dengan 4 karakteristik berikut ini:
•
•
•
•
Deskripsi Siapa, Apa
Ketersediaan Jumlah dan kualitas
Waktu Kapan digunakan
Durasi Berapa lama dipakai
SOFTWARE PROJECT ESTIMATION
•
To achieve reliable cost and effort estimates, a number of
options arise:
a) Delay estimation until late in the project (obviously, we can achieve
100% accurate estimates after the project is complete!).
b) Base estimates on similar projects that have already been
completed.
c) Use relatively simple decomposition techniques to generate project
cost and effort estimates.
d) Use one or more empirical models for software cost and effort
estimation.
Teknik Dekomposisi
• Software sizing
• Problem based estimation
• LOC based estimation
• Function point based estimation
• Process based estimation
Contoh LOC based
Contoh FP based
Contoh Process based
COCOMO Model
• COnstructive COst MOdel.
• Address the following areas:
• Application composition model. Used during the early stages
of software engineering, when prototyping of user interfaces,
consideration of software and system interaction, assessment of
performance, and evaluation of technology maturity.
• Early design stage model. Used once requirements have been
stabilized and basic software architecture has been established.
• Post-architecture-stage model. Used during the construction
of the software.
Keputusan: Beli atau Buat?
• Software engineering managers are faced with a make/ buy
decision :
• (1) software may be purchased (or licensed) off-the-shelf,
• (2) “full-experience” or “partial-experience” software
components may be acquired and then modified and
integrated to meet specific needs, or
• (3) software may be custom built by an outside contractor
to meet the purchaser's specifications.
Outsourcing
• Software engineering activities are contracted to a third party
who does the work at lower cost and, hopefully, higher quality.
• Software work conducted within a company is reduced to a
contract management activity.
• The decision to outsource can be either strategic or tactical.
• (+) Cost savings can usually be achieved by reducing the number
of software people and the facilities (e.g., computers, network).
• (-) A company loses some control over the software that it needs.
A company runs the risk of putting the fate of its competitiveness
into the hands of a third party.
Six Generic Functions
• 1. Sizing of project deliverables. Work products include the external
representation of software (e.g., screen, reports), the software itself (e.g.,
KLOC), functionality delivered (e.g., function points), descriptive information
(e.g. documents).
• 2. Selecting project activities. The appropriate process framework is
selected and the software engineering task set is specified.
• 3. Predicting staffing levels. The number of people who will be available to
do the work is specified.
• 4. Predicting software effort. Estimation tools use one or more models
(e.g., Section 5.7) that relate the size of the project deliverables to the effort
required to produce them.
• 5. Predicting software cost. Given the results of step 4, costs can be
computed by allocating labor rates to the project activities noted in step 2.
• 6. Predicting software schedules. When effort, staffing level, and project
activities are known, a draft schedule can be produced by allocating labor
across software engineering activities based on recommended models for
effort distribution (Chapter 7).
Kesimpulan
• The software project planner must estimate three things
before a project begins:
•
•
•
•
How long it will take,
How much effort will be required, and
How many people will be involved.
In addition, the planner must predict the resources (hardware
and software) that will be required and the risk involved.
Kesimpulan
• Decomposition techniques require a delineation of
major software functions, followed by estimates of
either
• (1) the number of LOC,
• (2) selected values within the information domain,
• (3) the number of person-months required to implement each
function, or
• (4) the number of person-months required for each software
engineering activity.
LUNAK
PERTEMUAN 2
PERENCANAAN PROYEK
PERANGKAT LUNAK
Pendahuluan
• Software project management begins with a set of activities
that are called project planning.
• Before the project can begin, the manager and the software
team must estimate the work to be done, the resources that
will be required, and the time that will elapse from start to
finish.
• Whenever estimates are made, we look into the future and
accept some degree of uncertainty as a matter of course.
Pendahuluan
• Estimation begins with a description of the scope of the
product.
• The problem is then decomposed into a set of smaller
problems and each of these is estimated using historical
data and experience as guides.
• It is advisable to generate your estimates using at least two
different methods (as a cross check).
• Problem complexity and risk are considered before a final
estimate is made.
Tujuan Perencanaan PPL
To provide a framework that enables the manager to
make reasonable estimates of resources, cost, and
schedule.
Scope (Ruang Lingkup) PL
• The first activity in software project planning is the
determination of software scope.
• Unambiguous and understandable at the management and
technical levels.
• A statement of software scope must be bounded.
• Software scope describes the data and control to be
processed, function, performance, constraints, interfaces,
and reliability.
Mendapatkan Ruang Lingkup
• Conduct a preliminary meeting or interview.
• Example questions:
•
•
•
•
Who is behind the request for this work?
Who will use the solution?
What will be the economic benefit of a successful solution?
Is there another source for the solution?
Feasibility (Kelayakan)
• Scoping is not enough.
• “Can we build software to meet this scope? Is the project
feasible?”
• Four solid dimensions:
• Technology — Is it within the state of the art?
• Finance — Can development be completed at a cost the software
organization, its client, or the market can afford?
• Time — Will the project’s time-to-market beat the competition?
• Resources — Does the organization have the resources needed to
succeed?
Resources (Sumber Daya)
Perspektif Sumber Daya
• Masing-masing sumber daya tersebut dispesifikasikan
dengan 4 karakteristik berikut ini:
•
•
•
•
Deskripsi Siapa, Apa
Ketersediaan Jumlah dan kualitas
Waktu Kapan digunakan
Durasi Berapa lama dipakai
SOFTWARE PROJECT ESTIMATION
•
To achieve reliable cost and effort estimates, a number of
options arise:
a) Delay estimation until late in the project (obviously, we can achieve
100% accurate estimates after the project is complete!).
b) Base estimates on similar projects that have already been
completed.
c) Use relatively simple decomposition techniques to generate project
cost and effort estimates.
d) Use one or more empirical models for software cost and effort
estimation.
Teknik Dekomposisi
• Software sizing
• Problem based estimation
• LOC based estimation
• Function point based estimation
• Process based estimation
Contoh LOC based
Contoh FP based
Contoh Process based
COCOMO Model
• COnstructive COst MOdel.
• Address the following areas:
• Application composition model. Used during the early stages
of software engineering, when prototyping of user interfaces,
consideration of software and system interaction, assessment of
performance, and evaluation of technology maturity.
• Early design stage model. Used once requirements have been
stabilized and basic software architecture has been established.
• Post-architecture-stage model. Used during the construction
of the software.
Keputusan: Beli atau Buat?
• Software engineering managers are faced with a make/ buy
decision :
• (1) software may be purchased (or licensed) off-the-shelf,
• (2) “full-experience” or “partial-experience” software
components may be acquired and then modified and
integrated to meet specific needs, or
• (3) software may be custom built by an outside contractor
to meet the purchaser's specifications.
Outsourcing
• Software engineering activities are contracted to a third party
who does the work at lower cost and, hopefully, higher quality.
• Software work conducted within a company is reduced to a
contract management activity.
• The decision to outsource can be either strategic or tactical.
• (+) Cost savings can usually be achieved by reducing the number
of software people and the facilities (e.g., computers, network).
• (-) A company loses some control over the software that it needs.
A company runs the risk of putting the fate of its competitiveness
into the hands of a third party.
Six Generic Functions
• 1. Sizing of project deliverables. Work products include the external
representation of software (e.g., screen, reports), the software itself (e.g.,
KLOC), functionality delivered (e.g., function points), descriptive information
(e.g. documents).
• 2. Selecting project activities. The appropriate process framework is
selected and the software engineering task set is specified.
• 3. Predicting staffing levels. The number of people who will be available to
do the work is specified.
• 4. Predicting software effort. Estimation tools use one or more models
(e.g., Section 5.7) that relate the size of the project deliverables to the effort
required to produce them.
• 5. Predicting software cost. Given the results of step 4, costs can be
computed by allocating labor rates to the project activities noted in step 2.
• 6. Predicting software schedules. When effort, staffing level, and project
activities are known, a draft schedule can be produced by allocating labor
across software engineering activities based on recommended models for
effort distribution (Chapter 7).
Kesimpulan
• The software project planner must estimate three things
before a project begins:
•
•
•
•
How long it will take,
How much effort will be required, and
How many people will be involved.
In addition, the planner must predict the resources (hardware
and software) that will be required and the risk involved.
Kesimpulan
• Decomposition techniques require a delineation of
major software functions, followed by estimates of
either
• (1) the number of LOC,
• (2) selected values within the information domain,
• (3) the number of person-months required to implement each
function, or
• (4) the number of person-months required for each software
engineering activity.