2,076 research outputs found
A note on local well-posedness of generalized KdV type equations with dissipative perturbations
In this note we report local well-posedness results for the Cauchy problems
associated to generalized KdV type equations with dissipative perturbation for
given data in the low regularity -based Sobolev spaces. The method of
proof is based on the {\em contraction mapping principle} employed in some
appropriate time weighted spaces.Comment: 14 page
Property rights protection and access to bank loans: Evidence from private enterprises in China
Poor protection of private property has limited the access to bank loans by private enterprises in developing and transition economies. Under those circumstances, private entrepreneurs have resorted to various ways of enhancing the de facto protection of private property. Using a dataset of 3,073 private enterprises in China, this paper empirically investigates the impact of political participation and philanthropic activities - informal substitutes for the lack of formal protection of private property - on the access to bank loans. © 2006 The Authors Journal compilation © 2006 The European Bank for Reconstruction and Development.published_or_final_versio
Excludable public goods: Pricing and social welfare maximization
We compare two pricing strategies - buffet pricing and usage pricing - of excludable public goods for social welfare maximization. Buffet pricing is better than usage pricing for low consumer heterogeneity, while the opposite holds for high consumer heterogeneity. © 2009 Elsevier B.V. All rights reserved.preprin
Evaluating Summary Statistics with Mutual Information for Cosmological Inference
The ability to compress observational data and accurately estimate physical
parameters relies heavily on informative summary statistics. In this paper, we
introduce the use of mutual information (MI) as a means of evaluating the
quality of summary statistics in inference tasks. MI can assess the sufficiency
of summaries, and provide a quantitative basis for comparison. We propose to
estimate MI using the Barber-Agakov lower bound and normalizing flow based
variational distributions. To demonstrate the effectiveness of our method, we
compare three different summary statistics (namely the power spectrum,
bispectrum, and scattering transform) in the context of inferring reionization
parameters from mock images of 21~cm observations with Square Kilometre Array.
We find that this approach is able to correctly assess the informativeness of
different summary statistics and allows us to select the optimal set of
statistics for inference tasks.Comment: Accepted at the ICML 2023 Workshop on Machine Learning for
Astrophysics, comments welcom
Federated Learning over a Wireless Network: Distributed User Selection through Random Access
User selection has become crucial for decreasing the communication costs of
federated learning (FL) over wireless networks. However, centralized user
selection causes additional system complexity. This study proposes a network
intrinsic approach of distributed user selection that leverages the radio
resource competition mechanism in random access. Taking the carrier sensing
multiple access (CSMA) mechanism as an example of random access, we manipulate
the contention window (CW) size to prioritize certain users for obtaining radio
resources in each round of training. Training data bias is used as a target
scenario for FL with user selection. Prioritization is based on the distance
between the newly trained local model and the global model of the previous
round. To avoid excessive contribution by certain users, a counting mechanism
is used to ensure fairness. Simulations with various datasets demonstrate that
this method can rapidly achieve convergence similar to that of the centralized
user selection approach
Tensorized LSSVMs for Multitask Regression
Multitask learning (MTL) can utilize the relatedness between multiple tasks
for performance improvement. The advent of multimodal data allows tasks to be
referenced by multiple indices. High-order tensors are capable of providing
efficient representations for such tasks, while preserving structural
task-relations. In this paper, a new MTL method is proposed by leveraging
low-rank tensor analysis and constructing tensorized Least Squares Support
Vector Machines, namely the tLSSVM-MTL, where multilinear modelling and its
nonlinear extensions can be flexibly exerted. We employ a high-order tensor for
all the weights with each mode relating to an index and factorize it with CP
decomposition, assigning a shared factor for all tasks and retaining
task-specific latent factors along each index. Then an alternating algorithm is
derived for the nonconvex optimization, where each resulting subproblem is
solved by a linear system. Experimental results demonstrate promising
performances of our tLSSVM-MTL
Catalytic transfer hydrogenolysis of organosolv lignin using B-containing FeNi alloyed catalysts
© 2017 Elsevier B.V. In this work, FeB, NiB, and FeNiB nanomaterials were examined as catalysts for catalytic transfer hydrogenolysis (CTH) using supercritical ethanol (sc-EtOH) as the hydrogen donor and reaction solvent. The earth-abundant alloys were synthesized using simple aqueous chemical reductions and characterized using ICP-OES, XRD, and STEM-EDS. Using acetophenone to model the desired catalytic reactivity, FeNiB was identified as having superior reactivity (74% conversion) and selectivity for complete deoxygenation to ethylbenzene (84%) when compared to the monometallic materials. Given its high reactivity and selectivity for deoxygenation over ring saturation, FeNiB was screened as a lignin valorization catalyst. FeNiB mediates deoxygenation of aliphatic hydroxyl and carbonyls in organosolv lignin via CTH in sc-EtOH. A combination of gel permeation chromatography, GC/MS, and NMR spectroscopy was used to demonstrate the production of a slate of monomeric phenols with intact deoxygenated aliphatic side chains. In total, these results highlight the utility of CTH for the valorization of biorefinery-relevant lignin using an inexpensive, earth-abundant catalyst material and a green solvent system that can be directly derived from the polysaccharide fraction of lignocellulosic biomass
TSS: Transformation-Specific Smoothing for Robustness Certification
As machine learning (ML) systems become pervasive, safeguarding their
security is critical. However, recently it has been demonstrated that motivated
adversaries are able to mislead ML systems by perturbing test data using
semantic transformations. While there exists a rich body of research providing
provable robustness guarantees for ML models against norm bounded
adversarial perturbations, guarantees against semantic perturbations remain
largely underexplored. In this paper, we provide TSS -- a unified framework for
certifying ML robustness against general adversarial semantic transformations.
First, depending on the properties of each transformation, we divide common
transformations into two categories, namely resolvable (e.g., Gaussian blur)
and differentially resolvable (e.g., rotation) transformations. For the former,
we propose transformation-specific randomized smoothing strategies and obtain
strong robustness certification. The latter category covers transformations
that involve interpolation errors, and we propose a novel approach based on
stratified sampling to certify the robustness. Our framework TSS leverages
these certification strategies and combines with consistency-enhanced training
to provide rigorous certification of robustness. We conduct extensive
experiments on over ten types of challenging semantic transformations and show
that TSS significantly outperforms the state of the art. Moreover, to the best
of our knowledge, TSS is the first approach that achieves nontrivial certified
robustness on the large-scale ImageNet dataset. For instance, our framework
achieves 30.4% certified robust accuracy against rotation attack (within ) on ImageNet. Moreover, to consider a broader range of
transformations, we show TSS is also robust against adaptive attacks and
unforeseen image corruptions such as CIFAR-10-C and ImageNet-C.Comment: 2021 ACM SIGSAC Conference on Computer and Communications Security
(CCS '21
The Glauber model and flow analysis with Pb-Pb collisions at =2.76 TeV
This work presents data analysis on Pb-Pb collisions at =2.76 TeV with centrality . We present introduction and
Monte-Carlo simulation results of the Glauber model, which shed light on the
initial geometric configuration of heavy ion collisions. Three-dimensional
correlation function is plotted, and Fourier decomposition is carried out in
order to obtain elliptic flow. Based on the assumption that non-flow effect is
less prominent in long-range area, we separate it from the second Fourier
decomposition of two-particle correlation function by making polynomial curve
fitting.Comment: 10 pages,8 figures, revisions are made, accepted by ICAPM 2022
Conference Proceeding
HDAC6 inhibition alleviates acute pulmonary embolism: a possible future therapeutic option
Introduction. Acute pulmonary embolism (APE) is a clinical syndrome of pulmonary circulation disorder caused by obstruction of the pulmonary artery or its branches. Histone deacetylase 6 (HDAC6) has been reported to play an important role in lung-related diseases. However, the functional role of HDAC6 in APE remains unclear.
Material and methods. Male Sprague Dawley rats were used. The APE model was constructed by inserting an intravenous cannula into the right femoral vein and injecting Sephadex G-50 microspheres (12 mg/kg; 300 μm in diameter). After 1 h, the control and APE rats were intraperitoneally injected with tubastatin A (TubA) (40 mg/kg, an inhibitor of HDAC6) and sampled at 24 h after modeling. H&E staining, arterial blood gas analysis, and wet/dry (W/D) weight ratio were used to evaluate the histopathological changes and pulmonary function in APE rats. ELISA, Western blot, and immunohistochemistry were used to explore the potential mechanism of HDAC6-mediated inflammation in APE.
Results. The results indicated that HDAC6 expression was significantly increased in lungs of APE rats. TubA treatment in vivo decreased HDAC6 expression in lung tissues. HDAC6 inhibition alleviated histopathological damage and pulmonary dysfunction, as evidenced by decreased PaO2/FiO2 ratio and W/D weight ratio in APE rats. Furthermore, HDAC6 inhibition alleviated APE-induced inflammatory response. Specifically, APE rats exhibited increased production of pro-inflammatory cytokines, including tumor necrosis factor-alpha (TNF-α), interleukin (IL)-1β, IL-6, and IL-18, however, this increase was reversed by HDAC6 inhibition. Meanwhile, the activation of the NLRP3 inflammasome was also observed in lungs of APE rats, while HDAC6 inhibition blocked this activation. Mechanically, we demonstrated that HDAC6 inhibition blocked the activation of the protein kinase B (AKT)/extracellular signal-regulated protein kinase (ERK) signaling pathway, a classic pathway promoting inflammation.
Conclusions. These findings demonstrate that the inhibition of HDAC6 may alleviate lung dysfunction and pathological injury resulting from APE by blocking the AKT/ERK signaling pathway, providing new theoretical fundamentals for APE therapy
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