8,638 research outputs found
Status and Future Perspectives for Lattice Gauge Theory Calculations to the Exascale and Beyond
In this and a set of companion whitepapers, the USQCD Collaboration lays out
a program of science and computing for lattice gauge theory. These whitepapers
describe how calculation using lattice QCD (and other gauge theories) can aid
the interpretation of ongoing and upcoming experiments in particle and nuclear
physics, as well as inspire new ones.Comment: 44 pages. 1 of USQCD whitepapers
Metamodel-based importance sampling for structural reliability analysis
Structural reliability methods aim at computing the probability of failure of
systems with respect to some prescribed performance functions. In modern
engineering such functions usually resort to running an expensive-to-evaluate
computational model (e.g. a finite element model). In this respect simulation
methods, which may require runs cannot be used directly. Surrogate
models such as quadratic response surfaces, polynomial chaos expansions or
kriging (which are built from a limited number of runs of the original model)
are then introduced as a substitute of the original model to cope with the
computational cost. In practice it is almost impossible to quantify the error
made by this substitution though. In this paper we propose to use a kriging
surrogate of the performance function as a means to build a quasi-optimal
importance sampling density. The probability of failure is eventually obtained
as the product of an augmented probability computed by substituting the
meta-model for the original performance function and a correction term which
ensures that there is no bias in the estimation even if the meta-model is not
fully accurate. The approach is applied to analytical and finite element
reliability problems and proves efficient up to 100 random variables.Comment: 20 pages, 7 figures, 2 tables. Preprint submitted to Probabilistic
Engineering Mechanic
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