On improving efficiency of model checking through systematically ...

out the problem characterization and techniques applied to deal with the
problem in Section 5.3.
5.1 Experiment procedure
Since our approach involves several tools and steps, we set up a uniform
procedure to do an experiment which consists of the following steps:
1. Construct a model in Nbac input language as we discussed in Section
2.3. The input model can be directly specified in Nbac input language,
or manually transformed from an XTG model, or automatically
transformed from a Lustre program.
2. Input the abovementioned model of the system to Nbac. Use the following
command to get the abstract model:
>nbac -analysis 2 foo.ba --partition "-maxloc N" -obdd
-o bar.ba
The meaning of options in the above command is as follows:
• foo.ba: file containing an input model
• bar.ba: file containing an output abstract model
• -analysis 2: type of analysis is a combination of forward and
backward analysis
• --partition "-maxloc N": this option controls the level of abstraction
by limiting the number of locations in the control structure.
The larger N, the less abstract the model.
• -obdd: this option is used to specify the format of the Boolean
expression
• -o: output the abstract model to a file
3. Chose some models to do experiments. Nbac generates several abstract
models. The level of abstraction is represented informally by
the number of locations. We prefer the model that contain 3-4 locations,
meaning that N in the above command is set to 3 or 4, for our
convenience in the simulation and problem analysis since it turned out
that we had to trace the execution by hand for a few cases.
4. Transform Nbac abstract model to Uppaal model. We use the tool
nbac2uppaal we have developed to do this step. The command is as
follows:
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