116 research outputs found
Physical parameters reconstruction of a fixed–fixed mass-spring system from its characteristic data
AbstractIn this paper, an inverse problem of constructing a linear n degree of freedom mass-spring system from part of its physical parameters and part of modality of its maximal or minimal natural frequencies is considered. The solvability and the expression of the solution is derived. The numerical algorithms and some numerical examples are given
The least-squares solutions of inconsistent matrix equation over symmetric and antipersymmetric matrices
AbstractIn this paper, we are concerned with the following two problems. In Problem I, we describe the set S of real n × n symmetric and antipersymmetric matrices such that minimize the Frobenius norm of LG − E for G, E in Rn × n. In Problem II, we find the unique Ľ in the setsfS, satisfying ∥L∗ − L∥ = minLϵS ∥L∗ − L∥, where L∗ ϵ Rn × n is a given matrix and ∥ · ∥ is the Frobenius norm. We derive a general expression of the set S. For Problem II, we prove the existence and the uniqueness of the solution and provide the expression of this unique solution. We also report some numerical results to support the theory established in the paper
BertNet: Harvesting Knowledge Graphs with Arbitrary Relations from Pretrained Language Models
It is crucial to automatically construct knowledge graphs (KGs) of diverse
new relations to support knowledge discovery and broad applications. Previous
KG construction methods, based on either crowdsourcing or text mining, are
often limited to a small predefined set of relations due to manual cost or
restrictions in text corpus. Recent research proposed to use pretrained
language models (LMs) as implicit knowledge bases that accept knowledge queries
with prompts. Yet, the implicit knowledge lacks many desirable properties of a
full-scale symbolic KG, such as easy access, navigation, editing, and quality
assurance. In this paper, we propose a new approach of harvesting massive KGs
of arbitrary relations from pretrained LMs. With minimal input of a relation
definition (a prompt and a few shot of example entity pairs), the approach
efficiently searches in the vast entity pair space to extract diverse accurate
knowledge of the desired relation. We develop an effective search-and-rescore
mechanism for improved efficiency and accuracy. We deploy the approach to
harvest KGs of over 400 new relations from different LMs. Extensive human and
automatic evaluations show our approach manages to extract diverse accurate
knowledge, including tuples of complex relations (e.g., "A is capable of but
not good at B"). The resulting KGs as a symbolic interpretation of the source
LMs also reveal new insights into the LMs' knowledge capacities.Comment: ACL 2023 (Findings); Code available at
https://github.com/tanyuqian/knowledge-harvest-from-lm
Photometric Metallicity Calibration with SDSS and SCUSS and its Application to distant stars in the South Galactic Cap
Based on SDSS g, r and SCUSS (South Galactic Cap of u-band Sky Survey)
photometry, we develop a photometric calibration for estimating the stellar
metallicity from and colors by using the SDSS spectra of 32,542 F-
and G-type main sequence stars, which cover almost deg in the
south Galactic cap. The rms scatter of the photometric metallicity residuals
relative to spectrum-based metallicity is dex when , and
dex when . Due to the deeper and more accurate magnitude of SCUSS
band, the estimate can be used up to the faint magnitude of . This
application range of photometric metallicity calibration is wide enough so that
it can be used to study metallicity distribution of distant stars. In this
study, we select the Sagittarius (Sgr) stream and its neighboring field halo
stars in south Galactic cap to study their metallicity distribution. We find
that the Sgr stream at the cylindrical Galactocentric coordinate of
kpc, kpc exhibits a relative rich metallicity
distribution, and the neighboring field halo stars in our studied fields can be
modeled by two-Gaussian model, with peaks respectively at [Fe/H] and
[Fe/H].Comment: 8 pages, 7 figures, Accepted for publication in MNRA
Project Overview of the Beijing-Arizona Sky Survey
The Beijing-Arizona Sky Survey (BASS) is a wide-field two-band photometric
survey of the Northern Galactic Cap using the 90Prime imager on the 2.3 m Bok
telescope at Kitt Peak. It is a four-year collaboration between the National
Astronomical Observatory of China and Steward Observatory, the University of
Arizona, serving as one of the three imaging surveys to provide photometric
input catalogs for target selection of the Dark Energy Spectroscopic Instrument
(DESI) project. BASS will take up to 240 dark/grey nights to cover an area of
about 5400 deg in the and bands. The 5 limiting AB
magnitudes for point sources in the two bands, corrected for the Galactic
extinction, are 24.0 and 23.4 mag, respectively. BASS, together with other DESI
imaging surveys, will provide unique science opportunities that cover a wide
range of topics in both Galactic and extragalactic astronomy.Comment: 10 pages, submitted to PAS
The Galactic extinction and reddening from the South Galactic Cap U-band Sky Survey: u band galaxy number counts and color distribution
We study the integral Galactic extinction and reddening based on the galaxy
catalog of the South Galactic Cap U-band Sky Survey (SCUSS), where band
galaxy number counts and color distribution are used to derive the
Galactic extinction and reddening respectively. We compare these independent
statistical measurements with the reddening map of \citet{Schlegel1998}(SFD)
and find that both the extinction and reddening from the number counts and
color distribution are in good agreement with the SFD results at low extinction
regions ( mag). However, for high extinction regions
( mag), the SFD map overestimates the Galactic reddening
systematically, which can be approximated by a linear relation ]. By combing the results of galaxy number counts and
color distribution together, we find that the shape of the Galactic extinction
curve is in good agreement with the standard extinction law of
\cite{ODonnell1994}
The First Data Release of the Beijing-Arizona Sky Survey
The Beijing-Arizona Sky Survey (BASS) is a new wide-field legacy imaging
survey in the northern Galactic cap using the 2.3m Bok telescope. The survey
will cover about 5400 deg in the and bands, and the expected
5 depths (corrected for the Galactic extinction) in the two bands are
24.0 and 23.4 mag, respectively. BASS started observations in January 2015, and
has completed about 41% of the whole area as of July 2016. The first data
release contains both calibrated images and photometric catalogs obtained in
2015 and 2016. The depths of single-epoch images in the two bands are 23.4 and
22.9 mag, and the full depths of three epochs are about 24.1 and 23.5 mag,
respectively.Comment: 16 pages, published by A
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