In this article, we present a concrete realisation of the ETCS hybrid level 3 concept, whose practical viability was evaluated in a field demonstration in 2017. Hybrid level 3 introduces virtual subsections as subdivisions of classical track sections with trackside train detection. Our approach introduces an add-on for the radio block centre (RBC) of Thales, called virtual block function (VBF), which computes the occupation states of the virtual subsections using the train position reports, train integrity information, and the track occupation states. From the perspective of the RBC, the VBF behaves as an interlocking that transmits all signal aspects for virtual signals introduced for each virtual subsection to the RBC. We report on the development of the VBF, implemented as a formal B model executed at runtime using ProB and successfully used in a field demonstration to control real trains. Keywords B-method • Animation • Model-based testing • Model checking • ETCS
Assessment of patient-reported symptoms was successfully realized in radiation oncology routine. Overall, both groups showed a high symptom burden. The results prove the need of systematic symptom assessment and programs for early integrated supportive and palliative care in radiation oncology.
Abstract. We present a symbolic reachability analysis approach for B that can provide a significant speedup over traditional explicit state model checking. The symbolic analysis is implemented by linking ProB to LTSmin, a high-performance language independent model checker. The link is achieved via LTSmin's Pins interface, allowing ProB to benefit from LTSmin's analysis algorithms, while only writing a few hundred lines of glue-code, along with a bridge between ProB and C using ØMQ. ProB supports model checking of several formal specification languages such as B, Event-B, Z and Tla + . Our experiments are based on a wide variety of B-Method and Event-B models to demonstrate the efficiency of the new link. Among the tested categories are state space generation and deadlock detection; but action detection and invariant checking are also feasible in principle. In many cases we observe speedups of several orders of magnitude. We also compare the results with other approaches for improving model checking, such as partial order reduction or symmetry reduction. We thus provide a new scalable, symbolic analysis algorithm for the B-Method and Event-B, along with a platform to integrate other model checking improvements via LTSmin in the future.
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