区域控制器的安全需求建模与自动验证

轨道交通区域控制器是我国轨道交通信号系统选型的主流制式--基于通信的列车控制系统的核心子系统,其突出的安全性使得安全需求的形式化验证成为一个非常重要的问题.但是区域控制器自身的复杂性以及领域知识的繁杂难以掌握,使得形式化方法很难应用到安全需求的验证中去.针对这些问题,提出一种安全需求的自动验证方法,使用半形式化的问题框架方法来建模和分解安全需求,根据需求模型自动生成安全需求的验证模型和验证性质,在此基础上自动生成验证模型的Scade语言实现,并通过DesignVerifier验证器对需求进行组合验证.最后,使用某个实际案例区域控制器的一个子问题CAL_EOA进行了研究,实验结果证明了该方法的可行性与有效性.它能够自动地将安全需求模型进行组合验证,改善了验证的效率.

Safety Requirements Modeling and Automatic Verification for Zone Controllers

The rail transit zone controller (ZC) is a core sub-system of the communication-based train control (CBTC) system, which is the mainstream choice of China''s rail transit systems. Its outstanding safety makes formal verification of safety requirements a very important issue. However, the complexity of ZC itself and the rail transit domain knowledge make it difficult to apply formal methods to the verification of safety requirements. To solve these problems, this paper proposes an automated verification approach for safety requirements. It models and decomposes safety requirements using a semi-formal Problem Frames approach (PF), automatically generates verification model and verification properties, implements the verification problem with Scade automatically, and finlly performs formal verification with model checker Design Verifier. Finally, a sub-problem of ZC, CAL_EOA from real case is studied. The experiment results show the feasibility and effectiveness of our approach. The safety requirements are automatically decomposed and compositionally verified, thus greatly improving the verification efficiency.