Formal requirements specification in safety-critical railway signaling system

Many critical control systems are developed using formal methods. When software applied to such systems is developed, the employment of formal methods in the software requirements specification and verification will provide increased assurance for such applications. Earlier error of overlooked requirement specification can be detected using formal specification method. Also the testing and full verification to examine all reachable states using model checking to undertake formal verification are able to be completed. In this paper, we proposed an eclectic approach to incorporate Z(Zed) formal language and `Statemate MAGNUM' which is formal method tools using Statechart. Also we applied the proposed method to safety-critical railway signaling systems for the formal requirement specification and analyzed the specification results.