In contrast to the full life cycle V&V process for the simple waterfall SDLC model shown inthe previous graphic, a statement of work for V&V may define a narrow role. It may restrict the V&V role to a subset of development life cycle phases or a role that does not parallel the development process in any way. An example of such a situation is shown in the image above
In this example, V&V is restricted to only a portion of a total Verification, Validation & Accreditation process that is typical in the Department of Defense. Verification is the process of ensuring that the software does what its author intended it to do. Validation addresses the question of whether the software properly represents the real world (the model should not be too crude or too refined for the purpose intended). Accreditation is the assertion by a responsible authority or regulating agent that the model is suitable and sufficient for a specific use.
The V&V task in this case addresses only the verification process
with Validation and Accreditation not performed by V&V. Verification
begins with the hand-off of a completed model to the V&V process as
defined by the contract or statement of work. Models in this context includes
all types of coded simulations, algorithms, and formulas. The Special
Analysis Kernel is invoked first and outlines analysis and data gathering
that is needed to support the remaining kernels. If the model is a re-submittal
of one previously verified, the Change Analysis kernel is invoked. After
the Special Analysis kernel is complete (all exit criteria and outputs
have been addressed), the Test Planning kernel is invoked. It outlines
activities to develop verification tests and establishes the possible
need for special test tools or data that may need to be generated by the
Test Data/Tool Generation kernel. Two types of verification activities
(Code Analysis and Interface Verification) are conducted. Both using test
cases previously defined in the Test Planning kernel. Finally, the results
are documented and certification is granted or denied on the basis of
code analysis results and interface verification test results. Certification
is defined to mean that the model meets the intended requirements.
The structure of the V&V life cycle for the waterfall SDLC is significantly different from the V&V life cycle for model verification. The waterfall V&V life cycle parallels, step by step, the development phases and spans the entire SDLC. The result is a series of assessments and activities that recommend improvement in the quality of development products. The model verification V&V life cycle is independent of the software development life cycle, and occurs on a completed model before release to its intended users. The result of the V&V verification process is a fully verified model with known qualities as determined by code analysis and interface verification test results.
What should be apparent from the V&V Life Cycle figures are the similarities between the two examples. Both life cycles draw from the same pre-defined repository of kernels. Each kernel is a formalized set of activities that are repeatable and are supported by a repeatable management infrastructure that uses process control and metrics consistently among all activities and projects. By example, the V&V Life Cycle methodology has been applied to vastly different levels and roles of V&V. The waterfall SDLC required a robust, full life cycle V&V and the model verification required only a restricted role of V&V for a portion of the SDLC. Therefore, V&V has been optimized based on the needs of a particular project. The process remains standard because the kernels themselves are well defined, and formalized.
This lesson described a process that uses V&V
process kernels to define a life cycle for performing Verification and
Validation. The modular nature of the kernels facilitates the construction
of a V&V life cycle that meets the needs and constraints of any software
development effort or level of V&V involvement. Kernel components
were described and examples of a V&V life cycle for a simple waterfall
development life cycle and a V&V model verification task were provided.
The lesson showed how the kernel approach achieves a formalized and repeatable
V&V process. An optimized V&V process can be achieved using this
process to tailor standard, proven methods for different development models,
system types, or to meet the constraints of narrowly scoped V&V.
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