User-friendly formal specification languages - Conclusions drawn from industrial experience on model checking

Formal methods - such as model checking - have definite advantages over more commonplace verification techniques. By providing proof of the analyzed systems' correctness, they are especially useful in domains that are under regulatory supervision, like the nuclear industry. The foremost challenge for wider adoption of model checking is the effort and the expertise required for formalizing functional requirements into verifiable properties. A particular challenge in verifying the application software of industrial process control systems is taking into account the different sequencing and timing issues that arise from, e.g., the dynamic behavior of the plant processes being controlled. In this paper, we review specification languages that are aimed at making formal methods more accessible. We have collected 1079 sample formal properties from practical model checking projects in the nuclear industry, and identified repeatedly occurring property types. We present our findings, and based on the sample data, evaluate the applicability of different approaches on user-friendly property specification.