1,210,102 research outputs found
Checking Computations of Formal Method Tools - A Secondary Toolchain for ProB
We present the implementation of pyB, a predicate - and expression - checker
for the B language. The tool is to be used for a secondary tool chain for data
validation and data generation, with ProB being used in the primary tool chain.
Indeed, pyB is an independent cleanroom-implementation which is used to
double-check solutions generated by ProB, an animator and model-checker for B
specifications. One of the major goals is to use ProB together with pyB to
generate reliable outputs for high-integrity safety critical applications.
Although pyB is still work in progress, the ProB/pyB toolchain has already been
successfully tested on various industrial B machines and data validation tasks.Comment: In Proceedings F-IDE 2014, arXiv:1404.578
Who watches the watchers: Validating the ProB Validation Tool
Over the years, ProB has moved from a tool that complemented proving, to a
development environment that is now sometimes used instead of proving for
applications, such as exhaustive model checking or data validation. This has
led to much more stringent requirements on the integrity of ProB. In this paper
we present a summary of our validation efforts for ProB, in particular within
the context of the norm EN 50128 and safety critical applications in the
railway domain.Comment: In Proceedings F-IDE 2014, arXiv:1404.578
NASA schedules second in new Pioneer series
Description of Pioneer B solar prob
Symbolic Reachability Analysis of B through ProB and LTSmin
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 ZeroMQ. 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
Solar plasma experiment
Solar plasma experiment by Mariner IV space prob
Distribution of Avalanche Sizes in the Hysteretic Response of Random Field Ising Model on a Bethe Lattice at Zero Temperature
We consider the zero-temperature single-spin-flip dynamics of the
random-field Ising model on a Bethe lattice in the presence of an external
field h. We derive the exact self-consistent equations to determine the
distribution Prob(s) of avalanche sizes s, as the external field increases from
large negative to positive values. We solve these equations explicitly for a
rectangular distribution of the random fields for a linear chain and the Bethe
lattice of coordination number z=3, and show that in these cases, Prob(s)
decreases exponentially with s for large s for all h on the hysteresis loop. We
found that for z >3 and for small disorder, the magnetization shows a first
order discontinuity for several continuous and unimodel distributions of random
fields. The avalanche distribution Prob(s) varies as s^{-3/2} for large s near
the discontinuity.Comment: 30 pages, 10 eps figure
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