1,512 research outputs found
A study of phase separation processes in presence of dislocations in binary systems subjected to irradiation
Dislocation-assisted phase separation processes in binary systems subjected
to irradiation effect are studied analytically and numerically. Irradiation is
described by athermal atomic mixing in the form of ballistic flux with
spatially correlated stochastic contribution. While studying the dynamics of
domain size growth we have shown that the dislocation mechanism of phase
decomposition delays the ordering processes. It is found that spatial
correlations of the ballistic flux noise cause segregation of dislocation cores
in the vicinity of interfaces effectively decreasing the interface width. A
competition between regular and stochastic components of the ballistic flux is
discussed.Comment: 22 pages, 11 figure
Preconditioned Stochastic Gradient Langevin Dynamics for Deep Neural Networks
Effective training of deep neural networks suffers from two main issues. The
first is that the parameter spaces of these models exhibit pathological
curvature. Recent methods address this problem by using adaptive
preconditioning for Stochastic Gradient Descent (SGD). These methods improve
convergence by adapting to the local geometry of parameter space. A second
issue is overfitting, which is typically addressed by early stopping. However,
recent work has demonstrated that Bayesian model averaging mitigates this
problem. The posterior can be sampled by using Stochastic Gradient Langevin
Dynamics (SGLD). However, the rapidly changing curvature renders default SGLD
methods inefficient. Here, we propose combining adaptive preconditioners with
SGLD. In support of this idea, we give theoretical properties on asymptotic
convergence and predictive risk. We also provide empirical results for Logistic
Regression, Feedforward Neural Nets, and Convolutional Neural Nets,
demonstrating that our preconditioned SGLD method gives state-of-the-art
performance on these models.Comment: AAAI 201
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