5,500 research outputs found
Blind correction of the EB-leakage in the pixel domain
We study the problem of EB-leakage that is associated with incomplete
polarized CMB sky. In the blind case that assumes no additional information
about the statistical properties and amplitudes of the signal from the missing
sky region, we prove that the recycling method (Liu et al.~2018) gives the
unique best estimate of the EB-leakage. Compared to the previous method, this
method reduces the uncertainties in the BB power spectrum due to EB-leakage by
more than one order of magnitude in the most interesting domain of multipoles,
where is between and . This work also provides a useful
guideline for observational design of future CMB experiments.Comment: Minor modification
Metamodel Instance Generation: A systematic literature review
Modelling and thus metamodelling have become increasingly important in
Software Engineering through the use of Model Driven Engineering. In this paper
we present a systematic literature review of instance generation techniques for
metamodels, i.e. the process of automatically generating models from a given
metamodel. We start by presenting a set of research questions that our review
is intended to answer. We then identify the main topics that are related to
metamodel instance generation techniques, and use these to initiate our
literature search. This search resulted in the identification of 34 key papers
in the area, and each of these is reviewed here and discussed in detail. The
outcome is that we are able to identify a knowledge gap in this field, and we
offer suggestions as to some potential directions for future research.Comment: 25 page
Semi-automatic Database Design for Neuroscience Experiment Management Systems
Neuroinformatics provides tools for neuroscience researchers to study brain function. In order to handle experiment paradigms that change frequently, we are developing a semiautomatic database design tool that will enable an experiment management system (EMS) to manage data with flexibility while retaining the efficiency of a relational database
From top-hat masking to smooth transitions: P-filter and its application to polarized microwave sky maps
In CMB science, the simplest idea to remove a contaminated sky region is to
multiply the sky map with a mask that is 0 for the contaminated region and 1
elsewhere, which is also called a top-hat masking. Although it is easy to use,
such top-hat masking is known to suffer from various leakage problems.
Therefore, we want to extend the top-hat masking to a series of semi-analytic
functions called the P-filters. Most importantly, the P-filters can seamlessly
realize the core idea of masking in CMB science, and, meanwhile, guarantee
continuity up to the first derivative everywhere. The P-filters can
significantly reduce many leakage problems without additional cost, including
the leakages due to low-, high-, and band-pass filtering, and the E-to-E,
B-to-B, B-to-E, and E-to-B leakages. The workings of the P-filter are
illustrated by using the WMAP and Planck polarization sky maps. By comparison
to the corresponding WMAP/Planck masks, we show that the P-filter performs much
better than top-hat masking, and meanwhile, has the potential to supersede the
principal idea of masking in CMB science. Compared to mask apodization, the
P-filter is ``outward'', that tends to make proper use of the region that was
marked as 0; whereas apodization is ``inward'', that always kills more signal
in the region marked as 1.Comment: 19 pages and 11 figure
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