Lec.
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V Process Model
§ The V process model is a variant of the waterfall process model.
§ The V-Model (Verification and Validation Model) is a software
development process that emphasizes a parallel relationship
between development stages and corresponding testing
activities.
§ There are testing activities occurring throughout all the
waterfall software life cycle model stages and not just during
the software testing period.
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V
Process
Model
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V Process Model
§ For example, during requirements specification, the
requirements are evaluated for testability and an
STRS (Software testing requirements specification) may be written. This
document would describe the strategy necessary for
testing the requirements.
§ Testing is a full life-cycle activity and that it is
important to constantly consider the testability of any
software requirement and to design to allow for such
testability.
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Selecting an Appropriate
Life Cycle Model for a Project
§ A suitable life cycle model can possibly be selected
based on an analysis of issues such as the following:
Ø Characteristics of the software to be developed.
Ø Characteristics of the development team.
Ø Characteristics of the customer.
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§ Suppose a small team of
developers has been entrusted
with the task of building a small
auction site for a local university.
Using Process
§ The university administration is
Models
willing to spend some time at the
in a start to help develop the
requirements, but it is expected
Project - 1 that their availability will be limited
later.
§ The team has been given 4 months
to finish the project, and an
extension of the deadline seems
very improbable.
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§ It also seems that the auction
site will have some features
that are essential but will also
Using Process have some features that are
Models desirable but without which
the system can function
in a reasonably well.
§ With these constraints, it is
Project - 1 clear that a waterfall model is
not suitable for this project, as
the “all or nothing” risk that it
entails is unacceptable due to
the inflexible deadline.
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§ The iterative enhancement
model where each iteration
does a complete waterfall is
Using Process also not right as it requires
Models requirements analysis for each
iteration, and the users and
in a clients are not available later.
§ However, the iterative delivery
Project - 1 approach in which the
complete requirements are
done in the first iteration, but
delivery is done in iterations
seems well suited.
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§ From the requirements, the
project team can decide what
functionality is essential to
have in a working system and
Using Process include it in the first iteration.
Models § The other desirable features
can be planned for the second
in a iteration.
§ With this approach, the
Project - 1 chances of completing the first
iteration before the final
deadline increase. That is, with
this model, the chances of
delivering a working system
increase.
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§ Consider another project,
where a university wants to
automate the registration
Using Process
process.
Models § It already has a database of
courses and pre-requisites, and
in a a database of student records.
§ In this project, as the
Project - 2 requirements are well
understood (since registrations
have been happening
manually), the waterfall model
seems to be the optimum.
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Next Week Assignments
§ Choose or design the process model you will use
to start working on your project.
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