5,231 research outputs found
Pseudo-Einstein and Q-flat metrics with eigenvalue estimates on CR-hypersurfaces
Let be the smooth boundary of a bounded strongly pseudo-convex
domain in a complete Stein manifold . Then (1) For ,
admits a pseudo-Eistein metric; (2) For , admits
a Fefferman metric of zero CR Q-curvature; and (3) for a compact strictly
pseudoconvex CR embeddable 3-manifold , its CR Paneitz operator is a
closed operator
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
AlignFlow: Cycle Consistent Learning from Multiple Domains via Normalizing Flows
Given datasets from multiple domains, a key challenge is to efficiently
exploit these data sources for modeling a target domain. Variants of this
problem have been studied in many contexts, such as cross-domain translation
and domain adaptation. We propose AlignFlow, a generative modeling framework
that models each domain via a normalizing flow. The use of normalizing flows
allows for a) flexibility in specifying learning objectives via adversarial
training, maximum likelihood estimation, or a hybrid of the two methods; and b)
learning and exact inference of a shared representation in the latent space of
the generative model. We derive a uniform set of conditions under which
AlignFlow is marginally-consistent for the different learning objectives.
Furthermore, we show that AlignFlow guarantees exact cycle consistency in
mapping datapoints from a source domain to target and back to the source
domain. Empirically, AlignFlow outperforms relevant baselines on image-to-image
translation and unsupervised domain adaptation and can be used to
simultaneously interpolate across the various domains using the learned
representation.Comment: AAAI 202
Proportional fairness in wireless powered CSMA/CA based IoT networks
This paper considers the deployment of a hybrid wireless data/power access
point in an 802.11-based wireless powered IoT network. The proportionally fair
allocation of throughputs across IoT nodes is considered under the constraints
of energy neutrality and CPU capability for each device. The joint optimization
of wireless powering and data communication resources takes the CSMA/CA random
channel access features, e.g. the backoff procedure, collisions, protocol
overhead into account. Numerical results show that the optimized solution can
effectively balance individual throughput across nodes, and meanwhile
proportionally maximize the overall sum throughput under energy constraints.Comment: Accepted by Globecom 201
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