78 research outputs found
Local Ensemble Transform Kalman Filter: a non-stationary control law for complex adaptive optics systems on ELTs
We propose a new algorithm for an adaptive optics system control law which
allows to reduce the computational burden in the case of an Extremely Large
Telescope (ELT) and to deal with non-stationary behaviors of the turbulence.
This approach, using Ensemble Transform Kalman Filter and localizations by
domain decomposition is called the local ETKF: the pupil of the telescope is
split up into various local domains and calculations for the update estimate of
the turbulent phase on each domain are performed independently. This data
assimilation scheme enables parallel computation of markedly less data during
this update step. This adapts the Kalman Filter to large scale systems with a
non-stationary turbulence model when the explicit storage and manipulation of
extremely large covariance matrices are impossible. First simulation results
are given in order to assess the theoretical analysis and to demonstrate the
potentiality of this new control law for complex adaptive optics systems on
ELTs.Comment: Proceedings of the AO4ELT3 conference; 8 pages, 3 figure
An Evaluation of GPT-4 on the ETHICS Dataset
This report summarizes a short study of the performance of GPT-4 on the
ETHICS dataset. The ETHICS dataset consists of five sub-datasets covering
different fields of ethics: Justice, Deontology, Virtue Ethics, Utilitarianism,
and Commonsense Ethics. The moral judgments were curated so as to have a high
degree of agreement with the aim of representing shared human values rather
than moral dilemmas. GPT-4's performance is much better than that of previous
models and suggests that learning to work with common human values is not the
hard problem for AI ethics.Comment: 8 page
Local ensemble transform Kalman filter, a fast non-stationary control law for adaptive optics on ELTs: theoretical aspects and first simulation results
We propose a new algorithm for an adaptive optics system control law, based
on the Linear Quadratic Gaussian approach and a Kalman Filter adaptation with
localizations. It allows to handle non-stationary behaviors, to obtain
performance close to the optimality defined with the residual phase variance
minimization criterion, and to reduce the computational burden with an
intrinsically parallel implementation on the Extremely Large Telescopes (ELTs).Comment: This paper was published in Optics Express and is made available as
an electronic reprint with the permission of OSA. The paper can be found at
the following URL on the OSA website: http://www.opticsinfobase.org/oe/ .
Systematic or multiple reproduction or distribution to multiple locations via
electronic or other means is prohibited and is subject to penalties under la
Investigations of physicochemical properties of bottom-ash materials for use them as secondary raw materials
In this paper chemical content and particle size distribution of bottom-ash material are defined; results of differential thermal and X-ray analyzes are given; processes of phase transformations occurring during heating, are examined for possible use of the waste to produce ceramic products. Studies have shown that effective specific activity of radionuclides in the material under examination would have no effect on radiation safety of the finished product
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