3,749 research outputs found
Assessing the effect of lens mass model in cosmological application with updated galaxy-scale strong gravitational lensing sample
By comparing the dynamical and lensing masses of early-type lens galaxies,
one can constrain both the cosmological parameters and the density profiles of
galaxies. We explore the constraining power on cosmological parameters and the
effect of the lens mass model in this method with 161 galaxy-scale strong
lensing systems, which is currently the largest sample with both high
resolution imaging and stellar dynamical data. We assume a power-law mass model
for the lenses, and consider three different parameterizations for
(i.e., the slope of the total mass density profile) to include the effect of
the dependence of on redshift and surface mass density. When treating
(i.e., the slope of the luminosity density profile) as a universal
parameter for all lens galaxies, we find the limits on the cosmological
parameter are quite weak and biased, and also heavily dependent on
the lens mass model in the scenarios of parameterizing with three
different forms. When treating as an observable for each lens, the
unbiased estimate of can be obtained only in the scenario of
including the dependence of on both the redshift and the surface mass
density, that is at 68\% confidence level
in the framework of a flat CDM model. We conclude that the significant
dependencies of on both the redshift and the surface mass density, as
well as the intrinsic scatter of among the lenses, need to be properly
taken into account in this method.Comment: Accepted for publication in MNRAS; 17 pages, 5 figures, 2 table
Geometry-Aware Face Completion and Editing
Face completion is a challenging generation task because it requires
generating visually pleasing new pixels that are semantically consistent with
the unmasked face region. This paper proposes a geometry-aware Face Completion
and Editing NETwork (FCENet) by systematically studying facial geometry from
the unmasked region. Firstly, a facial geometry estimator is learned to
estimate facial landmark heatmaps and parsing maps from the unmasked face
image. Then, an encoder-decoder structure generator serves to complete a face
image and disentangle its mask areas conditioned on both the masked face image
and the estimated facial geometry images. Besides, since low-rank property
exists in manually labeled masks, a low-rank regularization term is imposed on
the disentangled masks, enforcing our completion network to manage occlusion
area with various shape and size. Furthermore, our network can generate diverse
results from the same masked input by modifying estimated facial geometry,
which provides a flexible mean to edit the completed face appearance. Extensive
experimental results qualitatively and quantitatively demonstrate that our
network is able to generate visually pleasing face completion results and edit
face attributes as well
DDRF: Denoising Diffusion Model for Remote Sensing Image Fusion
Denosing diffusion model, as a generative model, has received a lot of
attention in the field of image generation recently, thanks to its powerful
generation capability. However, diffusion models have not yet received
sufficient research in the field of image fusion. In this article, we introduce
diffusion model to the image fusion field, treating the image fusion task as
image-to-image translation and designing two different conditional injection
modulation modules (i.e., style transfer modulation and wavelet modulation) to
inject coarse-grained style information and fine-grained high-frequency and
low-frequency information into the diffusion UNet, thereby generating fused
images. In addition, we also discussed the residual learning and the selection
of training objectives of the diffusion model in the image fusion task.
Extensive experimental results based on quantitative and qualitative
assessments compared with benchmarks demonstrates state-of-the-art results and
good generalization performance in image fusion tasks. Finally, it is hoped
that our method can inspire other works and gain insight into this field to
better apply the diffusion model to image fusion tasks. Code shall be released
for better reproducibility
Potential of Geo-neutrino Measurements at JUNO
The flux of geoneutrinos at any point on the Earth is a function of the
abundance and distribution of radioactive elements within our planet. This flux
has been successfully detected by the 1-kt KamLAND and 0.3-kt Borexino
detectors with these measurements being limited by their low statistics. The
planned 20-kt JUNO detector will provide an exciting opportunity to obtain a
high statistics measurement, which will provide data to address several
questions of geological importance. This paper presents the JUNO detector
design concept, the expected geo-neutrino signal and corresponding backgrounds.
The precision level of geo-neutrino measurements at JUNO is obtained with the
standard least-squares method. The potential of the Th/U ratio and mantle
measurements is also discussed.Comment: 8 pages, 6 figures, an additional author added, final version to
appear in Chin. Phys.
HEAVY TRUCK COLLISION WITH BRIDGE PIERS
Based on bridge failure data compiled by the New York State Department of Transportation, collision, both caused by vessels and vehicles, is the second leading cause of bridge failures after hydraulic. The current AASHTO-LRFD (2017) specification recommends designing a bridge pier vulnerable to vehicular impacts for an equivalent static force of 2,670-kN (600 kips) applied in a horizontal plane at a distance of 1.5 m (5.0 feet) above the ground level. The vast majority of research studies on vehicular collision with bridge piers have been carried out with single-unit trucks, which are typically classified as medium-duty vehicles weighing about 89 kN (20,000 lb). Yet, collision events that involve severe bridge damage are generally caused by heavy-duty trucks, generally tractor-semitrailers weighing 360 kN (80,000 lb). The handful of tests that were conducted to study heavy truck collision employed rigid piers, which means that the deformation and failure mechanisms of the piers were neglected. This study proposed a performance-based approach for designing a bridge pier subject to impact by a tractor-semitrailer weighing up to 360 kN (80,000 lb) based on a computational investigation. Validated, high-fidelity finite element simulations of collisions between tractor-semitrailers and reinforced concrete bridge piers have been carried out to investigate the demands imposed upon, and damage modes of, concrete piers. Through extensive numerical simulation of heavy vehicle (tractor-semitrailer) impacts on piers, the impact force time histories were simplified in the form of analytical triangular pulse functions. The parameters of these functions were derived through numerical regression based on the simulation results. A performance-based approach that relates demands (in terms of the applied force time histories) and capacity (in terms of acceptable shear distortion and plastic rotation) was proposed for the design of bridge piers vulnerable to heavy vehicle impact. Since many collision failures have been observed to be dominated by shear failure, the proposed performance-based approach used capacity-design concepts from earthquake engineering to mitigate collapse by minimizing shear distortion of piers impacted by heavy vehicles. Simulation results in this study have shown that the capacity design method can significantly reduce the shear distortion in the piers when subject to heavy truck impact. The risk of pier collapse in a given impact event was also evaluated based on Monte Carlo simulations, and a risk-based design framework was proposed in this study. The proposed risk-based design approach can serve as a powerful tool for the bridge owners to leverage the capacity of bridge piers and the risk of bridge damage caused by the impact event
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