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Chapter 5. Verification and Validation
Development of
train control meta model
Development of
model constraints
Design and implementation of
code generators
for the meta model
Design of domain framework
Definition of
model constraints
Dynamic Testing
(of gen. code)
Development of
model of
train control standard
Implementation of
domain framework
Model Constraint
Checking
Dynamic Testing
Design and Implementation of
Verification & Validation Suite
Verification
Validation
time
Figure 5.2.: Software development life cycle for DSM in the railway domain
Requirements Specifications [11].
To directly integrate verification and validation in the development process, the original tool
chain for the GOPPRR meta meta model extension (see Section 4.6) has to be extended, which
is shown in Figure 5.3. The generator for functional testing [78, p. 316] refers to a concrete
dynamic testing category that should be applied.
It must be emphasised that this extended tool chain still is very general since it does not yet
take the domain framework into account, which always heavily depends on the concrete meta
model. Furthermore, the code generation also depends on the domain framework because it
builds the link between models and the framework. Thus, a complete or rather more concrete
tool chain is given in Part III for a certain example in form of a case study.
5.4. Conclusion
This chapter introduced standards for safety-critical systems and discussed the issues for
software development of such systems. Besides standards directly related to the domain of
train control systems, also a general standard in form of the DIN EN 61508 was exemplary
introduced. The DO-178B for airborne systems was used to additionally introduce principles
and techniques for a complete different problem domain.
Since all standards are life cycle oriented, a specialised software life cycle was developed,
which directly integrates the development of a DSL for a certain train control standards in
general. Also, considerations for the development as FLOSS were taken into account.
The general tool chain for the GOPPRR meta model was extended about the integration of
verification and validation according to the considerations related to the standards. Nevertheless,
the integration of the software life cycle for DSM into the life cycle of the EN 50128 cannot be
realised in the case study because it would exceed the limits of a dissertation.
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