3,598 research outputs found
Atmospheric Impairments and Mitigation Techniques for High-Frequency Earth-Space Communication System in Heavy Rain Region: A Brief Review
This work surveys the atmospheric impairments that affect a satellite link operating in a high-frequency band, such as Ka and Q/V bands, particularly in heavy rain regions. The impacts of hydrometeors and cloud attenuation are emphasised and discussed along with the contribution of gases and scintillation to signal fade. Also, propagation impairment mitigation techniques are reviewed from the perspective of satellite operators in heavy rain areas
Chiral symmetry restoration and properties of Goldstone bosons at finite temperature
We study chiral symmetry restoration by analyzing thermal properties of QCD's
(pseudo-)Goldstone bosons, especially the pion. The meson properties are
obtained from the spectral densities of mesonic imaginary-time correlation
functions. To obtain the correlation functions, we solve the Dyson-Schwinger
equations and the inhomogeneous Bethe-Salpeter equations in the leading
symmetry-preserving rainbow-ladder approximation. In the chiral limit, the pion
and its partner sigma degenerate at the critical temperature . At , it is found that the pion rapidly dissociates, which signals
deconfinement phase transition. Beyond the chiral limit, the pion dissociation
temperature can be used to define the pseudo-critical temperature of chiral
phase crossover, which is consistent with that obtained by the maximum point of
the chiral susceptibility. The parallel analysis for kaon and pseudoscalar
suggests that heavy mesons may survive above
Compositional Generalization and Decomposition in Neural Program Synthesis
When writing programs, people have the ability to tackle a new complex task
by decomposing it into smaller and more familiar subtasks. While it is
difficult to measure whether neural program synthesis methods have similar
capabilities, what we can measure is whether they compositionally generalize,
that is, whether a model that has been trained on the simpler subtasks is
subsequently able to solve more complex tasks. In this paper, we focus on
measuring the ability of learned program synthesizers to compositionally
generalize. We first characterize several different axes along which program
synthesis methods would be desired to generalize, e.g., length generalization,
or the ability to combine known subroutines in new ways that do not occur in
the training data. Based on this characterization, we introduce a benchmark
suite of tasks to assess these abilities based on two popular existing
datasets, SCAN and RobustFill. Finally, we make first attempts to improve the
compositional generalization ability of Transformer models along these axes
through novel attention mechanisms that draw inspiration from a human-like
decomposition strategy. Empirically, we find our modified Transformer models
generally perform better than natural baselines, but the tasks remain
challenging.Comment: Published at the Deep Learning for Code (DL4C) Workshop at ICLR 202
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