2,095 research outputs found
Did InsurTech Promote the Development of Insurance Inclusion? Empirical Evidence from Chinaʼs Rural Areas
departmental bulletin pape
2-(4-Pyridinio)benzimidazolium tetrachloridopalladium(II)
The asymmetric unit of the title compound, (C12H11N3)[PdCl4], consists of a 2-(4-pyridinio)benzimidazolium cation and two half [PdCl4]2− anions, which are located on inversion centres. The cations lie in sheets parallel to (1). The cations and anions are connected by N—H⋯Cl and C—H⋯Cl contacts
Rectify the Regression Bias in Long-Tailed Object Detection
Long-tailed object detection faces great challenges because of its extremely
imbalanced class distribution. Recent methods mainly focus on the
classification bias and its loss function design, while ignoring the subtle
influence of the regression branch. This paper shows that the regression bias
exists and does adversely and seriously impact the detection accuracy. While
existing methods fail to handle the regression bias, the class-specific
regression head for rare classes is hypothesized to be the main cause of it in
this paper. As a result, three kinds of viable solutions to cater for the rare
categories are proposed, including adding a class-agnostic branch, clustering
heads and merging heads. The proposed methods brings in consistent and
significant improvements over existing long-tailed detection methods,
especially in rare and common classes. The proposed method achieves
state-of-the-art performance in the large vocabulary LVIS dataset with
different backbones and architectures. It generalizes well to more difficult
evaluation metrics, relatively balanced datasets, and the mask branch. This is
the first attempt to reveal and explore rectifying of the regression bias in
long-tailed object detection
A path to precision cosmology: synergy between four promising late-universe cosmological probes
In the next decades, it is necessary to forge new late-universe cosmological
probes to precisely constrain the Hubble constant and the equation of state of
dark energy simultaneously. In this work, we show that the four typical
late-universe cosmological probes, the 21 cm intensity mapping (IM), fast radio
burst (FRB), gravitational wave (GW) standard siren, and strong gravitational
lensing (SGL), are expected to be forged into useful tools in solving the
Hubble tension and exploring dark energy. We propose that the synergy of them
is rather important in cosmology. We simulate the 21 cm IM, FRB, GW, and SGL
data based on the hypothetical observations of the Hydrogen Intensity and
Real-time Analysis eXperiment (HIRAX), the Square Kilometre Array (SKA), the
Einstein Telescope (ET), and the Large Synoptic Survey Telescope (LSST),
respectively. We find that the four probes show obviously different parameter
degeneracy orientations in cosmological constraints, so any combination of them
can break the parameter degeneracies and thus significantly improve the
constraint precision. The joint 21 cm IM+FRB+GW+SGL data can provide the
constraint errors of and in the CDM model, which meet the standard of
precision cosmology, i.e., the constraint precision of parameters is better
than 1%. In addition, the joint data give in the CDM
model, and and in the CDM model,
which are all better than the constraints obtained by the CMB+BAO+SN data. We
show that the synergy between the four late-universe cosmological probes has
magnificent prospects.Comment: 28 pages, 9 figures; accepted for publication in JCA
A sex-role-preference model for HIV transmission among men who have sex with men in China
Background: Men who have sex with men (MSM) are much more likely to be infected with HIV
than the general population. China has a sizable population of MSM, including gay, bisexual men,
money boys and some rural workers. So reducing HIV infection in this population is an important
component of the national HIV/AIDS prevention and control program.
Methods: We develop a mathematical model using a sex-role-preference framework to predict
HIV infection in the MSM population and to evaluate different intervention strategies.
Results: An analytic formula for the basic reproduction ratio R0 was obtained; this yields R0 =
3.9296 in the current situation, so HIV will spread very fast in the MSM population if no intervention
measure is implemented in a timely fashion. The persistence of HIV infection and the existence of
disease equilibrium (or equilibria) are also shown. We utilized our model to simulate possible
outcomes of antiretroviral therapy and vaccination for the MSM population. We compared the
effects of these intervention measures under different assumptions about MSM behaviour. We also
found that R0 is a decreasing function of the death rate of HIV-infected individuals, following a
power law at least asymptotically.
Conclusion: HIV will spread very fast in the MSM population unless intervention measures are
implemented urgently. Antiretroviral therapy can have substantial impact on the reduction of HIV
among the MSM population, even if disinhibition is considered. The effect of protected sexual
behaviour on controlling the epidemic in the MSM population largely depends on the sex-ratio
preference of different sub-populations
AdaDiff: Adaptive Step Selection for Fast Diffusion
Diffusion models, as a type of generative models, have achieved impressive
results in generating images and videos conditioned on textual conditions.
However, the generation process of diffusion models involves denoising for
dozens of steps to produce photorealistic images/videos, which is
computationally expensive. Unlike previous methods that design
``one-size-fits-all'' approaches for speed up, we argue denoising steps should
be sample-specific conditioned on the richness of input texts. To this end, we
introduce AdaDiff, a lightweight framework designed to learn instance-specific
step usage policies, which are then used by the diffusion model for generation.
AdaDiff is optimized using a policy gradient method to maximize a carefully
designed reward function, balancing inference time and generation quality. We
conduct experiments on three image generation and two video generation
benchmarks and demonstrate that our approach achieves similar results in terms
of visual quality compared to the baseline using a fixed 50 denoising steps
while reducing inference time by at least 33%, going as high as 40%.
Furthermore, our qualitative analysis shows that our method allocates more
steps to more informative text conditions and fewer steps to simpler text
conditions.Comment: 10 pages, 5 figure
Photon blockade with a trapped -type three-level atom in asymmetrical cavity
We propose a scheme to manipulate strong and nonreciprocal photon blockades
in asymmetrical Fabry-Perot cavity with a -type three-level atom.
Utilizing the mechanisms of both conventional and unconventional blockade, the
strong photon blockade is achieved by the anharmonic eigenenergy spectrum
brought by -type atom and the destructive quantum interference effect
induced by a microwave field. By optimizing the system parameters, the
manipulation of strong photon blockade over a wide range of cavity detuning can
be realized. Using spatial symmetry breaking introduced by the asymmetry of
cavity, the direction-dependent nonreciprocal photon blockade can be achieved,
and the nonreciprocity can reach the maximum at optimal cavity detuning. In
particular, manipulating the occurring position of nonreciprocal photon
blockade can be implemented by simply adjusting the cavity detuning. Our scheme
provides feasible access for generating high-quality nonreciprocal
single-photon sources
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