Imperial College London
Portrait Picture

Professor David van Dyk

Faculty of Natural Sciences, Department of Mathematics

Chair in Statistics
 
 
 
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Contact

 

+44 (0)20 7594 8574d.van-dyk Website

 
 
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Assistant

 

Mr David Whittaker +44 (0)20 7594 8481

 
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Location

 

539Huxley BuildingSouth Kensington Campus

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Summary

 

Publications

Citation

BibTex format

@unpublished{Chen:2018,
author = {Chen, Y and Meng, X-L and Wang, X and van, Dyk D and Marshall, HL and Kashyap, VL},
publisher = {arXiv},
title = {Calibration concordance for astronomical instruments via multiplicative shrinkage},
url = {http://arxiv.org/abs/1711.09429v3},
year = {2018}
}
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RIS format (EndNote, RefMan)

TY  - UNPB
AB  - Calibration data are often obtained by observing several well-understoodobjects simultaneously with multiple instruments, such as satellites formeasuring astronomical sources. Analyzing such data and obtaining properconcordance among the instruments is challenging when the physical sourcemodels are not well understood, when there are uncertainties in "known"physical quantities, or when data quality varies in ways that cannot be fullyquantified. Furthermore, the number of model parameters increases with both thenumber of instruments and the number of sources. Thus, concordance of theinstruments requires careful modeling of the mean signals, the intrinsic sourcedifferences, and measurement errors. In this paper, we propose a log-Normalhierarchical model and a more general log-t model that respect themultiplicative nature of the mean signals via a half-variance adjustment, yetpermit imperfections in the mean modeling to be absorbed by residual variances.We present analytical solutions in the form of power shrinkage in special casesand develop reliable MCMC algorithms for general cases. We apply our method toseveral data sets obtained with a variety of X-ray telescopes such as Chandra.We demonstrate that our method provides helpful and practical guidance forastrophysicists when adjusting for disagreements among instruments.
AU  - Chen,Y
AU  - Meng,X-L
AU  - Wang,X
AU  - van,Dyk D
AU  - Marshall,HL
AU  - Kashyap,VL
PB  - arXiv
PY  - 2018///
TI  - Calibration concordance for astronomical instruments via multiplicative shrinkage
UR  - http://arxiv.org/abs/1711.09429v3
UR  - http://hdl.handle.net/10044/1/63399
ER  -
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