B-PERFect

Abstract

An independent safety assessment of railway software systems is performed by RATP (Régie Autonome des Transports Parisiens) for all safety-critical systems before their deployment in its network. Whenever possible, this activity is performed using the PERF approach (Proof Executed over a Retro-engineered Formal model). PERF is a methodology which handles formal verification of already developed software. This approach is applied to a variety of software systems, developed using languages such as SCADE, Ada or C. It provides an alternative verification that can be applied for the independent safety assessment of critical systems used by RATP. In this paper, we propose the B-PERFect method to generalize the application of the PERF approach for critical systems which are based on the B method. In particular, this paper focuses on transformation strategy from B language to the pivot language of PERF: HLL. HLL is a synchronous data-flow language equipped with formal verification techniques. The differences between B and HLL are pointed out and the translation process is presented in this regard.

Formal Verification of the European Train Control System (ETCS) for Better Energy Efficiency Using a Timed and Asynchronous Model

“…Using NuSMV and OCRA (a tool for examining the refinement of temporal contracts), the operation of the rail traffic control system under incorrect signal sequences is explored [23]. An alternative verification technique to model checking-theorem proving using PERF-is used in [24]. The deductive verification tool KeYmaera, for parametric analysis of train control in ETCS, is covered in [25].…”

Temporal Verification of Relay-Based Railway Traffic Control Systems Using the Integrated Model of Distributed Systems

“…Theorem-proving using PERF, the alternative verification method to the model checking, is applied in [32].…”