On improving efficiency of model checking through systematically ...
On improving efficiency of model checking through systematically ...
On improving efficiency of model checking through systematically ...
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Chapter 6<br />
Conclusions<br />
In this master thesis we introduced a systematic approach to combine a<br />
tool that provides abstraction technique and a <strong>model</strong> checker to improve<br />
<strong>efficiency</strong> <strong>of</strong> <strong>model</strong> <strong>checking</strong>. In short, our approach uses an existing tool to<br />
generate abstract <strong>model</strong>s for a <strong>model</strong> checker to verify. We hoped that the<br />
abstraction tool would help to reduce the <strong>model</strong> <strong>of</strong> the system being verified<br />
and thus <strong>model</strong> <strong>checking</strong> on that <strong>model</strong> would be more efficient. If this<br />
approach works, it will help to employ abstraction in <strong>model</strong> checkers without<br />
directly implementing the abstraction function in those <strong>model</strong> checkers.<br />
Nbac, PMC and Uppaal are tools involved in the implementation <strong>of</strong> our<br />
approach. Nbac is a <strong>model</strong> checker that has a built-in abstraction utility<br />
which is based on the theoretical framework <strong>of</strong> abstract interpretation. PMC<br />
and Uppaal are two <strong>model</strong> checkers aimed at real-time systems. We started<br />
the implementation <strong>of</strong> our approach by combining Nbac and PMC. Dueto<br />
the fact that PMC lacks in some important features such as Boolean variables<br />
and operators, logical operator OR, we had to switch our implementation to<br />
combining Nbac and Uppaal. Our approach is depicted by Figure 6.1.<br />
Of course, to do the <strong>model</strong> <strong>checking</strong>, an input <strong>model</strong> <strong>of</strong> the system is<br />
needed. Since Nbac is responsible for generating abstract <strong>model</strong>s, the input<br />
<strong>model</strong> must be specified in Nbac input language. Nbac input language is<br />
a low level language mainly consists <strong>of</strong> variable declarations and dataflow<br />
equations on variables. As a result, specifying an input system in Nbac specification<br />
language is a complicated job for verification engineers. Among<br />
three different ways to specify an input <strong>model</strong>, transforming a <strong>model</strong> <strong>model</strong>ed<br />
in PMC/Uppaal to an Nbac <strong>model</strong> is likely to be the most popular one.<br />
In Chapter 2, we have established a framework to do such transformation.<br />
It turned out that even when a transformation framework is available, the<br />
manual transformation is an error-prone process. A tool to take over that<br />
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