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arxiv_dataset-111001904.0496 | Image Quality Assessment for Omnidirectional Cross-reference Stitching
cs.CV
Along with the development of virtual reality (VR), omnidirectional images
play an important role in producing multimedia content with immersive
experience. However, despite various existing approaches for omnidirectional
image stitching, how to quantitatively assess the quality of stitched images is
still insufficiently explored. To address this problem, we establish a novel
omnidirectional image dataset containing stitched images as well as
dual-fisheye images captured from standard quarters of 0$^\circ$, 90$^\circ$,
180$^\circ$ and 270$^\circ$. In this manner, when evaluating the quality of an
image stitched from a pair of fisheye images (e.g., 0$^\circ$ and 180$^\circ$),
the other pair of fisheye images (e.g., 90$^\circ$ and 270$^\circ$) can be used
as the cross-reference to provide ground-truth observations of the stitching
regions. Based on this dataset, we further benchmark six widely used stitching
models with seven evaluation metrics for IQA. To the best of our knowledge, it
is the first dataset that focuses on assessing the stitching quality of
omnidirectional images.
| arxiv topic:cs.CV |
arxiv_dataset-111011904.0506 | Network depth: identifying median and contours in complex networks
stat.ME cond-mat.dis-nn physics.soc-ph
Centrality descriptors are widely used to rank nodes according to specific
concept(s) of importance. Despite the large number of centrality measures
available nowadays, it is still poorly understood how to identify the node
which can be considered as the `centre' of a complex network. In fact, this
problem corresponds to finding the median of a complex network. The median is a
non-parametric and robust estimator of the location parameter of a probability
distribution. In this work, we present the most natural generalisation of the
concept of median to the realm of complex networks, discussing its advantages
for defining the centre of the system and percentiles around that centre. To
this aim, we introduce a new statistical data depth and we apply it to networks
embedded in a geometric space induced by different metrics. The application of
our framework to empirical networks allows us to identify median nodes which
are socially or biologically relevant.
| arxiv topic:stat.ME cond-mat.dis-nn physics.soc-ph |
arxiv_dataset-111021904.0516 | Large-Scale Long-Tailed Recognition in an Open World
cs.CV cs.LG
Real world data often have a long-tailed and open-ended distribution. A
practical recognition system must classify among majority and minority classes,
generalize from a few known instances, and acknowledge novelty upon a never
seen instance. We define Open Long-Tailed Recognition (OLTR) as learning from
such naturally distributed data and optimizing the classification accuracy over
a balanced test set which include head, tail, and open classes. OLTR must
handle imbalanced classification, few-shot learning, and open-set recognition
in one integrated algorithm, whereas existing classification approaches focus
only on one aspect and deliver poorly over the entire class spectrum. The key
challenges are how to share visual knowledge between head and tail classes and
how to reduce confusion between tail and open classes. We develop an integrated
OLTR algorithm that maps an image to a feature space such that visual concepts
can easily relate to each other based on a learned metric that respects the
closed-world classification while acknowledging the novelty of the open world.
Our so-called dynamic meta-embedding combines a direct image feature and an
associated memory feature, with the feature norm indicating the familiarity to
known classes. On three large-scale OLTR datasets we curate from object-centric
ImageNet, scene-centric Places, and face-centric MS1M data, our method
consistently outperforms the state-of-the-art. Our code, datasets, and models
enable future OLTR research and are publicly available at
https://liuziwei7.github.io/projects/LongTail.html.
| arxiv topic:cs.CV cs.LG |
arxiv_dataset-111031904.0526 | Non-Hermitian Photonics based on Charge-Parity Symmetry
physics.optics cond-mat.mes-hall
Parity-time ($\mathcal{PT}$) symmetry, originally conceived for non-Hermitian
open quantum systems, has opened an excitingly new avenue for the coherent
control of light. By tailoring optical gain and loss in integrated photonic
structures, $\mathcal{PT}$ symmetric non-Hermitian photonics has found
applications in many fields ranging from single mode lasing to novel
topological matters. Here we propose a new paradigm towards non-Hermitian
photonics based on the charge-parity ($\mathcal{CP}$) symmetry that has the
potential to control the flow of light in an unprecedented way. In particular,
we consider continuous dielectric chiral materials, where the charge
conjugation and parity symmetries are broken individually, but preserved
jointly. Surprisingly, the phase transition between real and imaginary spectra
across the exceptional point is accompanied by a dramatic change of the
photonic band topology from dielectric to hyperbolic. We showcase broad
applications of $\mathcal{CP}$ symmetric photonics such as all-angle
polarization-dependent negative refraction materials, enhanced spontaneous
emission for laser engineering, and non-Hermitian topological photonics. The
$\mathcal{CP}$ symmetry opens an unexplored pathway for studying non-Hermitian
photonics without optical gain/loss by connecting two previously distinct
material properties: chirality and hyperbolicity, therefore providing a
powerful tool for engineering many promising applications in photonics and
other related fields.
| arxiv topic:physics.optics cond-mat.mes-hall |
arxiv_dataset-111041904.0536 | A $\pmb{\nu}$ Solution to the Strong CP Problem
hep-ph hep-ex
We present a new solution to the strong CP problem in which the imaginary
component of the up quark mass, $\mathcal{I}[m_u]$, acquires a tiny, but
non-vanishing value. This is achieved via a Dirac seesaw mechanism, which is
also responsible for the generation of the small neutrino masses. Consistency
with the observed value of the up quark mass is achieved via instanton
contributions arising from QCD-like interactions. In this framework, the value
of the neutron electric dipole moment is directly related to
$\mathcal{I}[m_u]$, which, due to its common origin with the neutrino masses,
implies that the neutron electric dipole moment is likely to be measured in the
next round of experiments. We also present a supersymmetric extension of this
Dirac seesaw model to stabilize the hierarchy among the scalar mass scales
involved in this new mechanism.
| arxiv topic:hep-ph hep-ex |
arxiv_dataset-111051904.0546 | Least Squares Auto-Tuning
math.OC cs.LG
Least squares is by far the simplest and most commonly applied computational
method in many fields. In almost all applications, the least squares objective
is rarely the true objective. We account for this discrepancy by parametrizing
the least squares problem and automatically adjusting these parameters using an
optimization algorithm. We apply our method, which we call least squares
auto-tuning, to data fitting.
| arxiv topic:math.OC cs.LG |
arxiv_dataset-111061904.0556 | Bai-Pollicott Algorithm for Markovian Products of Positive Matrices
math.PR
We consider the problem of estimating the top Lyapunov exponents for
Markovian products of positive matrices. We define a new transfer operator as a
matrix of classical transfer operators and prove its spectral properties. With
the spectral properties, we generalize (and provide a more theoretically
rigorous foundation for) an algorithm that was introduced informally by Bai and
formally by Pollicott based on dynamical zeta functions.
| arxiv topic:math.PR |
arxiv_dataset-111071904.0566 | Forescattered electron imaging of nanoparticles in a scanning electron
microscopy
cond-mat.mtrl-sci
In this study, we have used a Zr-Nb alloy containing well-defined
nano-precipitates as a model material in which to study imaging contrast
inversions (atomic number or diffraction contrast) observed with the
forescattered electron imaging system, ARGUSTM, in a scanning electron
microscope (SEM) when imaging a thin foil in a transmission geometry. The study
is based on Monte Carlo simulations and analysis of micrographs experimentally
acquired under different imaging conditions. Based on the results, imaging
conditions that enhance atomic number or diffraction contrast have been
proposed. Data acquired from the ARGUSTM imaging system in SEM has also been
compared with results from standard transmission electron microscopy and
scanning transmission electron microscopy imaging of the same material. These
results demonstrate the capability of the ARGUSTM system to investigate
microstructures in nano-scale materials.
| arxiv topic:cond-mat.mtrl-sci |
arxiv_dataset-111081904.0576 | Scalarizing Functions in Bayesian Multiobjective Optimization
cs.LG cs.NE stat.ML
Scalarizing functions have been widely used to convert a multiobjective
optimization problem into a single objective optimization problem. However,
their use in solving (computationally) expensive multi- and many-objective
optimization problems in Bayesian multiobjective optimization is scarce.
Scalarizing functions can play a crucial role on the quality and number of
evaluations required when doing the optimization. In this article, we study and
review 15 different scalarizing functions in the framework of Bayesian
multiobjective optimization and build Gaussian process models (as surrogates,
metamodels or emulators) on them. We use expected improvement as infill
criterion (or acquisition function) to update the models. In particular, we
compare different scalarizing functions and analyze their performance on
several benchmark problems with different number of objectives to be optimized.
The review and experiments on different functions provide useful insights when
using and selecting a scalarizing function when using a Bayesian multiobjective
optimization method.
| arxiv topic:cs.LG cs.NE stat.ML |
arxiv_dataset-111091904.0586 | Altered Dielectric Behaviour, Structure and Dynamics of Nanoconfined
Dipolar Liquids: Signatures of Enhanced Cooperativity
cond-mat.soft
Spherical confinement can alter the properties of a dipolar fluid in several
different ways. In an atomistic molecular dynamics simulation study of two
different dipolar liquids (SPC/E water and a model Stockmayer fluid) confined
to nanocavities of different radii ranging from Rc=1nm to 4nm, we find that the
Kirkwood correlation factor remains surprisingly small in water, but not so in
model Stockmayer liquid. This gives rise to an anomalous ultrafast relaxation
of the total dipole moment time correlation function (DMTCF). The static
dielectric constant of water under nanoconfinement (computed by employing
Clausius-Mossotti equation, the only exact relation) exhibits a strong
dependence on the size of the nanocavity with a remarkably slow convergence to
the bulk value. Interestingly, the value of the volume becomes ambiguous in
this nanoworld. It is determined by the liquid-surface interaction potential
and is to be treated with care because of the sensitivity of the
Clausius-Mossotti equation to the volume of the nanosphere. We discover that
the DMTCF for confined water exhibit a bimodal 1/f noise power spectrum. We
also comment on the applicability of certain theoretical formalisms that become
dubious in the nanoworld.
| arxiv topic:cond-mat.soft |
arxiv_dataset-111101904.0596 | A Scalable Multigrid Reduction Framework for Multiphase Poromechanics of
Heterogeneous Media
math.NA
Simulation of multiphase poromechanics involves solving a multi-physics
problem in which multiphase flow and transport are tightly coupled with the
porous medium deformation. To capture this dynamic interplay, fully implicit
methods, also known as monolithic approaches, are usually preferred. The main
bottleneck of a monolithic approach is that it requires solution of large
linear systems that result from the discretization and linearization of the
governing balance equations. Because such systems are non-symmetric,
indefinite, and highly ill-conditioned, preconditioning is critical for fast
convergence. Recently, most efforts in designing efficient preconditioners for
multiphase poromechanics have been dominated by physics-based strategies.
Current state-of-the-art "black-box" solvers such as algebraic multigrid (AMG)
are ineffective because they cannot effectively capture the strong coupling
between the mechanics and the flow sub-problems, as well as the coupling
inherent in the multiphase flow and transport process. In this work, we develop
an algebraic framework based on multigrid reduction (MGR) that is suited for
tightly coupled systems of PDEs. Using this framework, the decoupling between
the equations is done algebraically through defining appropriate interpolation
and restriction operators. One can then employ existing solvers for each of the
decoupled blocks or design a new solver based on knowledge of the physics. We
demonstrate the applicability of our framework when used as a "black-box"
solver for multiphase poromechanics. We show that the framework is flexible to
accommodate a wide range of scenarios, as well as efficient and scalable for
large problems.
| arxiv topic:math.NA |
arxiv_dataset-111111904.0606 | Entanglement of a cavity light produced by a superposed two-mode
coherent and subharmonic light
quant-ph
With the aid of the solutions of the Quantum Langevin equations, we have
calculated the Q-functions for the two-mode coherent and subharmonic cavity
light beams. We have then determined the Q-function for the superposed two-mode
coherent and subharmonic cavity light beams. With the help of the pertinent
Q-functions for cavity light beams, we determined the photon statistics,
quadrature statistics, and entanglement. we have obtained that the superposed
two-mode coherent and subharmonic cavity light beams are in a squeezed state
and the squeezing occurs in the plus quadrature. Besides, our analysis shows
that at steady state and at threshold, the superposed two-mode coherent and
subharmonic light beams have a maximum squeezing of $25\%$ below the two-mode
vacuum-state level. We have also clearly shown that the superposed two-mode
light beam is entangled at steady-state and threshold and the entanglement
turned out to be observed in the highly correlated squeezed photons with $75\%$
degree of entanglement.
| arxiv topic:quant-ph |
arxiv_dataset-111121904.0616 | Opportunities in Time-Domain Extragalactic Astrophysics with the NASA
Near-Earth Object Camera (NEOCam)
astro-ph.GA
This White Pape motivates the time domain extragalactic science case for the
NASA Near-Earth Object Camera (NEOCam). NEOCam is a NASA Planetary mission
whose goal is to discover and characterize asteroids and comets, to assess the
hazard to Earth from near-Earth objects, and to study the origin, evolution,
and fate of asteroids and comets. NEOCam will, however, cover 68% of the
extragalactic sky and as the NEOWISE-R mission has recently proved, infrared
information is now vital for identifying and characterizing the $\gtrsim$10
million IR bright Active Galactic Nuclei, as well as using the IR light curve
to provide deep insights into accretion disk astrophysics. NEOWISE-R data has
also been used to discover Super-luminous Supernovae, dust echos in Tidal
Disruption Events and detects all of the known $z\geq7$ quasars (and over 80%
of the known $z\geq6.70$ quasars). As such, for relatively little additional
cost, adding the capacity for additional NEOCam data processing (and/or
alerting) would have a massive scientific and legacy impact on extragalactic
time domain science.
| arxiv topic:astro-ph.GA |
arxiv_dataset-111131904.0626 | Similarities between policy gradient methods (PGM) in Reinforcement
learning (RL) and supervised learning (SL)
cs.LG cs.AI stat.ML
Reinforcement learning (RL) is about sequential decision making and is
traditionally opposed to supervised learning (SL) and unsupervised learning
(USL). In RL, given the current state, the agent makes a decision that may
influence the next state as opposed to SL (and USL) where, the next state
remains the same, regardless of the decisions taken, either in batch or online
learning. Although this difference is fundamental between SL and RL, there are
connections that have been overlooked. In particular, we prove in this paper
that gradient policy method can be cast as a supervised learning problem where
true label are replaced with discounted rewards. We provide a new proof of
policy gradient methods (PGM) that emphasizes the tight link with the cross
entropy and supervised learning. We provide a simple experiment where we
interchange label and pseudo rewards. We conclude that other relationships with
SL could be made if we modify the reward functions wisely.
| arxiv topic:cs.LG cs.AI stat.ML |
arxiv_dataset-111141904.0636 | Indications for transit timing variations in the exo-Neptune HAT-P-26b
astro-ph.EP
From its discovery, the low density transiting Neptune HAT-P-26b showed a
2.1-sigma detection drift in its spectroscopic data, while photometric data
showed a weak curvature in the timing residuals that required further follow-up
observations to be confirmed. To investigate this suspected variability, we
observed 11 primary transits of HAT-P-26b between March, 2015 and July, 2018.
For this, we used the 2.15 meter Jorge Sahade Telescope placed in San Juan,
Argentina, and the 1.2 meter STELLA and the 2.5 meter Nordic Optical Telescope,
both located in the Canary Islands, Spain. To add upon valuable information on
the transmission spectrum of HAT-P-26b, we focused our observations in the
R-band only. To contrast the observed timing variability with possible stellar
activity, we carried out a photometric follow-up of the host star along three
years. We carried out a global fit to the data and determined the individual
mid-transit times focusing specifically on the light curves that showed
complete transit coverage. Using bibliographic data corresponding to both
ground and space-based facilities, plus our new characterized mid-transit times
derived from parts-per-thousand precise photometry, we observed indications of
transit timing variations in the system, with an amplitude of ~4 minutes and a
periodicity of ~270 epochs. The photometric and spectroscopic follow-up
observations of this system will be continued in order to rule out any aliasing
effects caused by poor sampling and the long-term periodicity.
| arxiv topic:astro-ph.EP |
arxiv_dataset-111151904.0646 | Optical/NIR stellar absorption and emission-line indices from luminous
infrared galaxies
astro-ph.GA
We analyze a set of optical-to-near-infrared long-slit nuclear spectra of 16
infrared-luminous spiral galaxies. All of the studied sources present H$_2$
emission, which reflects the star-forming nature of our sample, and they
clearly display H I emission lines in the optical. Their continua contain many
strong stellar absorption lines, with the most common features due to Ca I, Ca
II, Fe I, Na I, Mg I, in addition to prominent absorption bands of TiO, VO,
ZrO, CN and CO. We report a homogeneous set of equivalent width (EW)
measurements for 45 indices, from optical to NIR species for the 16
star-forming galaxies as well as for 19 early type galaxies where we collected
the data from the literature. This selected set of emission and
absorption-feature measurements can be used to test predictions of the
forthcoming generations of stellar population models. We find correlations
among the different absorption features and propose here correlations between
optical and NIR indices, as well as among different NIR indices, and compare
them with model predictions. While for the optical absorption features the
models consistently agree with the observations,the NIR indices are much harder
to interpret. For early-type spirals the measurements agree roughly with the
models, while for star-forming objects they fail to predict the strengths of
these indices.
| arxiv topic:astro-ph.GA |
arxiv_dataset-111161904.0656 | A Quantum Engineer's Guide to Superconducting Qubits
quant-ph cond-mat.mes-hall physics.app-ph
The aim of this review is to provide quantum engineers with an introductory
guide to the central concepts and challenges in the rapidly accelerating field
of superconducting quantum circuits. Over the past twenty years, the field has
matured from a predominantly basic research endeavor to one that increasingly
explores the engineering of larger-scale superconducting quantum systems. Here,
we review several foundational elements -- qubit design, noise properties,
qubit control, and readout techniques -- developed during this period, bridging
fundamental concepts in circuit quantum electrodynamics (cQED) and
contemporary, state-of-the-art applications in gate-model quantum computation.
| arxiv topic:quant-ph cond-mat.mes-hall physics.app-ph |
arxiv_dataset-111171904.0666 | Theory Review of Neutrino Models and CP Violation
hep-ph
Although the measurement of the reactor angle has killed tribimaximal lepton
mixing, its descendants survive with charged lepton corrections, or in less
constrained forms such as trimaximal mixing and/or mu-tau symmetry, each with
characteristic predictions. Such patterns may be enforced by a remnant of some
non-Abelian discrete family symmetry, possibly together with a generalised CP
symmetry, which could originate from continuous gauge symmetry and/or
superstring theory in compactified extra dimensions, as a finite subgroup of
the modular symmetry.
| arxiv topic:hep-ph |
arxiv_dataset-111181904.0676 | Drawing HV-Restricted Planar Graphs
cs.CG
A strict orthogonal drawing of a graph $G=(V, E)$ in $\mathbb{R}^2$ is a
drawing of $G$ such that each vertex is mapped to a distinct point and each
edge is mapped to a horizontal or vertical line segment. A graph $G$ is
$HV$-restricted if each of its edges is assigned a horizontal or vertical
orientation. A strict orthogonal drawing of an $HV$-restricted graph $G$ is
good if it is planar and respects the edge orientations of $G$. In this paper,
we give a polynomial-time algorithm to check whether a given $HV$-restricted
plane graph (i.e., a planar graph with a fixed combinatorial embedding) admits
a good orthogonal drawing preserving the input embedding, which settles an open
question posed by Ma\v{n}uch et al. (Graph Drawing 2010). We then examine
$HV$-restricted planar graphs (i.e., when the embedding is not fixed), and give
a complete characterization of the $HV$-restricted biconnected outerplanar
graphs that admit good orthogonal drawings.
| arxiv topic:cs.CG |
arxiv_dataset-111191904.0686 | A search for solar axion induced signals with COSINE-100
hep-ex astro-ph.IM nucl-ex
We present results from a search for solar axions with the COSINE-100
experiment. We find no evidence of solar axion events from a data-set of
6,303.9 kg$\cdot$days exposure and set a 90\,\% confidence level upper limit on
the axion-electron coupling, $g_{ae}$, at 1.70~$\times$~$10^{-11}$ for an axion
mass less than 1\,keV/c$^2$. This limit excludes QCD axions heavier than
0.59\,eV/c$^2$ in the DFSZ model and 168.1\,eV/c$^2$ in the KSVZ model.
| arxiv topic:hep-ex astro-ph.IM nucl-ex |
arxiv_dataset-111201904.0696 | On the Performance of Differential Evolution for Hyperparameter Tuning
cs.LG cs.NE stat.ML
Automated hyperparameter tuning aspires to facilitate the application of
machine learning for non-experts. In the literature, different optimization
approaches are applied for that purpose. This paper investigates the
performance of Differential Evolution for tuning hyperparameters of supervised
learning algorithms for classification tasks. This empirical study involves a
range of different machine learning algorithms and datasets with various
characteristics to compare the performance of Differential Evolution with
Sequential Model-based Algorithm Configuration (SMAC), a reference Bayesian
Optimization approach. The results indicate that Differential Evolution
outperforms SMAC for most datasets when tuning a given machine learning
algorithm - particularly when breaking ties in a first-to-report fashion. Only
for the tightest of computational budgets SMAC performs better. On small
datasets, Differential Evolution outperforms SMAC by 19% (37% after
tie-breaking). In a second experiment across a range of representative datasets
taken from the literature, Differential Evolution scores 15% (23% after
tie-breaking) more wins than SMAC.
| arxiv topic:cs.LG cs.NE stat.ML |
arxiv_dataset-111211904.0706 | Le th\'eor\`eme de r\'eduction stable de Deligne et Mumford
math.AG
The stable reduction theorem of Deligne and Mumford --- The moduli space of
smooth projective curves of genus $g$ is a quasi-projective algebraic variety,
but is not projective. To understand its geometry, it may be crucial to
consider compactifications of this space. By allowing to parameterize as well
curves with controlled singularities (the so called stable curves), Deligne and
Mumford constructed a projective compactification. The properness of this
compactification translates into the stable reduction theorem that they prove,
its projectivity is a later theorem of Knudsen and Mumford. This text is based
on the oral presentation and aims at introducing these objects.
| arxiv topic:math.AG |
arxiv_dataset-111221904.0716 | Fluxon-induced losses in niobium thin-film cavities revisited
physics.acc-ph cond-mat.supr-con
Long standing data from niobium thin film accelerating cavities will be
revisited and analysed by a modified London model of RF superconductivity.
Firstly, the applicability of this model is explored using data of the BCS
surface resistance and its dependence on the RF magnetic field, temperature and
mean free path. Secondly, the RF losses from trapped magnetic flux are analysed
with regard to their dependence on these same parameters.
| arxiv topic:physics.acc-ph cond-mat.supr-con |
arxiv_dataset-111231904.0726 | Hidden Analytic Relations for Two-Loop Higgs Amplitudes in QCD
hep-th hep-ph
We compute the Higgs plus two-quark and one-gluon amplitudes ($H \rightarrow
q \bar{q} g$) and Higgs plus three-gluon amplitudes ($H \rightarrow 3g$) in the
Higgs effective theory with a general class of operators. By changing the
quadratic Casimir $C_F$ to $C_A$, the maximally transcendental parts of the $H
\rightarrow q \bar{q} g$ amplitudes turn out to be equivalent to that of the $H
\rightarrow 3g$ amplitudes, which also coincide with the counterparts in ${\cal
N}=4$ SYM. This generalizes the so-called maximal transcendentality principle
to the Higgs amplitudes with external quark states, thus to the full QCD
theory. We further verify that the correspondence applies also to two-loop form
factors of more general operators, in both QCD and scalar-YM theory. Another
interesting relation is also observed between the planar $H \rightarrow q
\bar{q} g$ amplitudes and the minimal density form factors in ${\cal N}=4$ SYM.
| arxiv topic:hep-th hep-ph |
arxiv_dataset-111241904.0736 | Interferometric scattering enables fluorescence-free electrokinetic
trapping of single nanoparticles in free solution
physics.ins-det physics.app-ph physics.bio-ph physics.optics q-bio.QM
Anti-Brownian traps confine single particles in free solution by closed-loop
feedback forces that directly counteract Brownian motion. The extended-duration
measurement of trapped objects allows detailed characterization of
photophysical and transport properties, as well as observation of infrequent or
rare dynamics. However, this approach has been generally limited to particles
that can be tracked by fluorescent emission. Here we present the
Interferometric Scattering Anti-Brownian ELectrokinetic trap (ISABEL trap),
which uses interferometric scattering rather than fluorescence to monitor
particle position. By decoupling the ability to track (and therefore trap) a
particle from collection of its spectroscopic data, the ISABEL trap enables
confinement and extended study of single particles that do not fluoresce, that
only weakly fluoresce, or which exhibit intermittent fluorescence or
photobleaching. This new technique significantly expands the range of nanoscale
objects that may be investigated at the single-particle level in free solution.
| arxiv topic:physics.ins-det physics.app-ph physics.bio-ph physics.optics q-bio.QM |
arxiv_dataset-111251904.0746 | Fashion-AttGAN: Attribute-Aware Fashion Editing with Multi-Objective GAN
cs.CV
In this paper, we introduce attribute-aware fashion-editing, a novel task, to
the fashion domain. We re-define the overall objectives in AttGAN and propose
the Fashion-AttGAN model for this new task. A dataset is constructed for this
task with 14,221 and 22 attributes, which has been made publically available.
Experimental results show the effectiveness of our Fashion-AttGAN on fashion
editing over the original AttGAN.
| arxiv topic:cs.CV |
arxiv_dataset-111261904.0756 | Partition of energy for a dissipative quantum oscillator
cond-mat.stat-mech cond-mat.quant-gas math-ph math.MP quant-ph
We reveal a new face of the old clich\'ed system: a dissipative quantum
harmonic oscillator. We formulate and study a quantum counterpart of the energy
equipartition theorem satisfied for classical systems.Both mean kinetic energy
$E_k$ and mean potential energy $E_p$ of the oscillator are expressed as $E_k =
\langle \mathcal E_k \rangle$ and $E_p = \langle \mathcal E_p \rangle$, where
$\langle \mathcal E_k \rangle$ and $ \langle \mathcal E_p \rangle$ are mean
kinetic and potential energies per one degree of freedom of the thermostat
which consists of harmonic oscillators too. The symbol $\langle ...\rangle$
denotes two-fold averaging: (i) over the Gibbs canonical state for the
thermostat and (ii) over thermostat oscillators frequencies $\omega$ which
contribute to $E_k$ and $E_p$ according to the probability distribution
$\mathbb{P}_k(\omega)$ and $\mathbb{P}_p(\omega)$, respectively. The role of
the system-thermostat coupling strength and the memory time is analysed for the
exponentially decaying memory function (Drude dissipation mechanism) and the
algebraically decaying damping kernel.
| arxiv topic:cond-mat.stat-mech cond-mat.quant-gas math-ph math.MP quant-ph |
arxiv_dataset-111271904.0766 | Multiple-interaction kinetic modelling of a virtual-item gambling
economy
physics.soc-ph econ.GN nlin.AO q-fin.EC
In recent years, there has been a proliferation of online gambling sites,
which made gambling more accessible with a consequent rise in related problems,
such as addiction. Hence, the analysis of the gambling behaviour at both the
individual and the aggregate levels has become the object of several
investigations. In this paper, resorting to classical methods of the kinetic
theory, we describe the behaviour of a multi-agent system of gamblers
participating in lottery-type games on a virtual-item gambling market. The
comparison with previous, often empirical, results highlights the ability of
the kinetic approach to explain how the simple microscopic rules of a
gambling-type game produce complex collective trends, which might be difficult
to interpret precisely by looking only at the available data.
| arxiv topic:physics.soc-ph econ.GN nlin.AO q-fin.EC |
arxiv_dataset-111281904.0776 | Infrared dust arcs around the stars: I. effect of the radiation pressure
astro-ph.SR
In this paper we consider the distribution of the interstellar dust in the
vicinity of the star under an influence of the stellar gravitation and
radiation pressure. This study is applicable to the stars with relatively weak
stellar wind and strong radiation, when the stellar radiation swept out the
interstellar dust much further from the star than the position of the bow shock
created by an interaction of the stellar and interstellar plasma flows. In this
case the number density of dust for a certain dust grains radius can be
calculated analytically based on the classical `cold model'. The dust density
distribution for the mixture of dust grains with different radii is calculated.
We also calculated intensity maps of the thermal infrared emission at 24~$\mu$m
from dust due to heating by the stellar radiation. It is shown that the
obtained maps of the infrared emission extremely depends on the model
parameters: material of dust grains, dust size distribution assumed in the
interstellar medium, the approach used to calculate the dust temperature. The
bright distinct arc at the intensity maps is seen for graphite dust grains and
almost disappears for silicates. Absolute values of intensity in the case of
graphite are several order of magnitudes larger than for silicates due to more
intensive heating of graphite. Possible application of the presented theory is
proposed as an algorithm for analysis of the observational images of the
infrared arc around the star.
| arxiv topic:astro-ph.SR |
arxiv_dataset-111291904.0786 | Base spacing distribution analysis for human genome
q-bio.OT
The distribution of bases spacing in human genome was investigated. An
analysis of the frequency of occurrence in the human genome of different
sequence lengths flanked by one type of nucleotide was carried out showing that
the distribution has no self-similar (fractal) structure. The results
nevertheless revealed several characteristic features: (i) the distribution for
short-range spacing is quite similar to the purely stochastic sequences; (ii)
the distribution for long-range spacing essentially deviates from the random
sequence distribution, showing strong long-range correlations; (iii) the
differences between (A, T) and (C, G) bases are quite significant; (iv) the
spacing distribution displays tiny oscillations.
| arxiv topic:q-bio.OT |
arxiv_dataset-111301904.0796 | Softwire Hub and Spoke Deployment Framework with Layer Two Tunneling
Protocol Version 2 (L2TPv2)
cs.NI
This document describes the framework of the Softwire ''Hub and Spoke''
solution with the Layer Two Tunneling Protocol version 2 (L2TPv2). The
implementation details specified in this document should be followed to achieve
interoperability among different vendor implementations.
| arxiv topic:cs.NI |
arxiv_dataset-111311904.0806 | Deep Fusion Network for Image Completion
cs.CV
Deep image completion usually fails to harmonically blend the restored image
into existing content, especially in the boundary area. This paper handles with
this problem from a new perspective of creating a smooth transition and
proposes a concise Deep Fusion Network (DFNet). Firstly, a fusion block is
introduced to generate a flexible alpha composition map for combining known and
unknown regions. The fusion block not only provides a smooth fusion between
restored and existing content, but also provides an attention map to make
network focus more on the unknown pixels. In this way, it builds a bridge for
structural and texture information, so that information can be naturally
propagated from known region into completion. Furthermore, fusion blocks are
embedded into several decoder layers of the network. Accompanied by the
adjustable loss constraints on each layer, more accurate structure information
are achieved. We qualitatively and quantitatively compare our method with other
state-of-the-art methods on Places2 and CelebA datasets. The results show the
superior performance of DFNet, especially in the aspects of harmonious texture
transition, texture detail and semantic structural consistency. Our source code
will be avaiable at: \url{https://github.com/hughplay/DFNet}
| arxiv topic:cs.CV |
arxiv_dataset-111321904.0816 | Cosmic Ray Models
astro-ph.HE
We review progress in high-energy cosmic ray physics focusing on recent
experimental results and models developed for their interpretation. Emphasis is
put on the propagation of charged cosmic rays, covering the whole range from
$\sim (20-50)$ GV, i.e. the rigidity when solar modulations can be neglected,
up to the highest energies observed. We discuss models aiming to explain the
anomalies in Galactic cosmic rays, the knee, and the transition from Galactic
to extragalactic cosmic rays.
| arxiv topic:astro-ph.HE |
arxiv_dataset-111331904.0826 | A silicon quantum-dot-coupled nuclear spin qubit
quant-ph
Single nuclear spins in the solid state have long been envisaged as a
platform for quantum computing, due to their long coherence times and excellent
controllability. Measurements can be performed via localised electrons, for
example those in single atom dopants or crystal defects. However, establishing
long-range interactions between multiple dopants or defects is challenging.
Conversely, in lithographically-defined quantum dots, tuneable interdot
electron tunnelling allows direct coupling of electron spin-based qubits in
neighbouring dots. Moreover, compatibility with semiconductor fabrication
techniques provides a compelling route to scaling to large numbers of qubits.
Unfortunately, hyperfine interactions are typically too weak to address single
nuclei. Here we show that for electrons in silicon metal-oxide-semiconductor
quantum dots the hyperfine interaction is sufficient to initialise, read-out
and control single silicon-29 nuclear spins, yielding a combination of the long
coherence times of nuclear spins with the flexibility and scalability of
quantum dot systems. We demonstrate high-fidelity projective readout and
control of the nuclear spin qubit, as well as entanglement between the nuclear
and electron spins. Crucially, we find that both the nuclear spin and electron
spin retain their coherence while moving the electron between quantum dots,
paving the way to long range nuclear-nuclear entanglement via electron
shuttling. Our results establish nuclear spins in quantum dots as a powerful
new resource for quantum processing.
| arxiv topic:quant-ph |
arxiv_dataset-111341904.0836 | Scl in graphs of groups
math.GT math.GR
Let G be a group acting on a tree with cyclic edge and vertex stabilizers.
Then stable commutator length (scl) is rational in G. Furthermore, scl varies
predictably and converges to rational limits in so-called "surgery" families.
This is a homological analog of the phenomenon of geometric convergence in
hyperbolic Dehn surgery.
| arxiv topic:math.GT math.GR |
arxiv_dataset-111351904.0846 | The Tilt of the Local Velocity Ellipsoid as Seen by Gaia
astro-ph.GA
The Gaia Radial Velocity Spectrometer (RVS) provides a sample of 7,224,631
stars with full six-dimensional phase space information. Bayesian distances of
these stars are available from the catalogue of Sch\"onrich et al. (2019). We
exploit this to map out the behaviour of the velocity ellipsoid within 5 kpc of
the Sun. We find that the tilt of the disc-dominated RVS sample is accurately
described by the relation $\alpha = (0.952 \pm 0.007)\arctan (|z|/R)$, where
($R,z$) are cylindrical polar coordinates. This corresponds to velocity
ellipsoids close to spherical alignment (for which the normalising constant
would be unity) and pointing towards the Galactic centre. Flattening of the
tilt of the velocity ellipsoids is enhanced close to the plane and Galactic
centre, whilst at high elevations far from the Galactic center the population
is consistent with exact spherical alignment. Using the LAMOST catalogue
cross-matched with Gaia DR2, we construct thin disc and halo samples of
reasonable purity based on metallicity. We find that the tilt of thin disc
stars straddles $\alpha = (0.909-1.038)\arctan (|z|/R)$, and of halo stars
straddles $\alpha = (0.927-1.063)\arctan (|z|/R)$. We caution against the use
of reciprocal parallax for distances in studies of the tilt, as this can lead
to serious artefacts.
| arxiv topic:astro-ph.GA |
arxiv_dataset-111361904.0856 | Comment on "Orientational Distribution of Free O-H Groups of Interfacial
Water is Exponential"
physics.chem-ph
In a recent letter (PRL,121,246101,2018), Sun et al. reported that combined
MD simulation and sum frequency generation vibrational spectroscopy (SFG-VS)
measurements led to conclusions of a broad and exponentially decaying
orientational distribution, and the presence of the free O-H group pointing
down to the bulk at the air/water interface. In this comment, we show that
their main conclusions are based on questionable interpretation of the SFG-VS
data presented in the letter [1], and are also contrary to the established data
analysis and interpretations in the literature [2-5].
| arxiv topic:physics.chem-ph |
arxiv_dataset-111371904.0866 | The Fornax Deep Survey (FDS) with VST. VI. Optical properties of the
dwarf galaxies in the Fornax cluster
astro-ph.GA
The Fornax Deep Survey Dwarf galaxy Catalog (FDSDC) includes 564 dwarf
galaxies in the Fornax cluster and the in-falling Fornax A subgroup. We use the
FDSDC galaxies for statistical analysis of the structural and stellar
population differences in the range of galactic environments within the Fornax
cluster. We present the standard scaling relations for the dwarfs and analyze
trends as a function of cluster-centric radius. We find a different behavior
for the bright dwarfs (-18.5 mag < M$_r$ < -16 mag) as compared to the fainter
ones (M$_r$ > -16 mag): While considering galaxies in the same magnitude-bins,
we find that, while for fainter dwarfs the g'-r' color is redder for lower
surface brightness objects (as expected from fading stellar populations), for
brighter dwarfs the color is redder for the higher surface brightness and
higher S\'ersic n objects. The trend of the bright dwarfs might be explained by
those galaxies being affected by harassment and by slower quenching of star
formation in their inner parts. As the fraction of early-type dwarfs with
respect to late-types increases toward the central parts of the cluster, the
color-surface brightness trends are also manifested in the cluster-centric
trends, confirming that it is indeed the environment that changes the galaxies.
We also estimate the strengths of the ram-pressure stripping, tidal disruption,
and harassment in the Fornax cluster, and find that our observations are
consistent with the theoretically expected ranges of galaxy properties where
each of those mechanisms dominate. We furthermore find that the luminosity
function, color-magnitude relation, and axis-ratio distribution of the dwarfs
in the center of the Fornax cluster are similar to those in the center of the
Virgo cluster.
| arxiv topic:astro-ph.GA |
arxiv_dataset-111381904.0876 | Cursive Multilingual Characters Recognition Based on Hard Geometric
Features
cs.CV
The cursive nature of multilingual characters segmentation and recognition of
Arabic, Persian, Urdu languages have attracted researchers from academia and
industry. However, despite several decades of research, still multilingual
characters classification accuracy is not up to the mark. This paper presents
an automated approach for multilingual characters segmentation and recognition.
The proposed methodology explores character based on their geometric features.
However, due to uncertainty and without dictionary support few characters are
over-divided. To expand the productivity of the proposed methodology a BPN is
prepared with countless division focuses for cursive multilingual characters.
Prepared BPN separates off base portioned indicates effectively with rapid
upgrade character acknowledgment precision. For reasonable examination, only
benchmark dataset is utilized.
| arxiv topic:cs.CV |
arxiv_dataset-111391904.0886 | Cool spots on the surface of the active giant PZ Mon
astro-ph.SR
Based on the multiband (BVRIJHKL) photometric observations of the active red
giant PZ Mon performed for the first time in the winter season of 2017-2018, we
have determined the main characteristics of the spotted stellar surface in a
parametric three-spot model. The unspotted surface temperature is Teff=4730 K,
the temperature of the cool spots is Tspot=3500 K, their relative area is about
41%, and the temperature of the warm spots is Twarm=4500 K with a maximum
relative area up to 20%. The distribution of spots over the stellar surface has
been modeled. The warm spots have been found to be distributed at various
longitudes in the hemisphere on the side of the secondary component and are
most likely a result of its influence.
| arxiv topic:astro-ph.SR |
arxiv_dataset-111401904.0896 | N$^{3}$LO predictions for the decay of the Higgs boson to bottom quarks
hep-ph
We present a fully-differential calculation of the $H\rightarrow
b\overline{b}$ decay at next-to-next- to-next-to-leading order (N$^3$LO)
accuracy. Our calculation considers diagrams in which the Higgs boson couples
directly to the bottom quarks, i.e. the perturbative order we consider is
$\mathcal{O}(\alpha_s^3y_b^2)$. In order to regulate the infrared divergences
present at this order we use the Projection-to-Born technique coupled with
N-jettiness slicing. After validating our methodology at
next-to-next-to-leading order (NNLO) we present exclusive jet rates and
differential distributions for jet observables at N3LO accuracy using the
Durham jet algorithm in the Higgs rest frame.
| arxiv topic:hep-ph |
arxiv_dataset-111411904.0906 | Helly meets Garside and Artin
math.GR math.AT math.GT
A graph is Helly if every family of pairwise intersecting combinatorial balls
has a nonempty intersection. We show that weak Garside groups of finite type
and FC-type Artin groups are Helly, that is, they act geometrically on Helly
graphs. In particular, such groups act geometrically on spaces with convex
geodesic bicombing, equipping them with a nonpositive-curvature-like structure.
That structure has many properties of a CAT(0) structure and, additionally, it
has a combinatorial flavor implying biautomaticity. As immediate consequences
we obtain new results for FC-type Artin groups (in particular braid groups and
spherical Artin groups) and weak Garside groups, including e.g.\ fundamental
groups of the complements of complexified finite simplicial arrangements of
hyperplanes, braid groups of well-generated complex reflection groups, and
one-relator groups with non-trivial center. Among the results are:
biautomaticity, existence of EZ and Tits boundaries, the Farrell-Jones
conjecture, the coarse Baum-Connes conjecture, and a description of higher
order homological and homotopical Dehn functions. As a mean of proving the
Helly property we introduce and use the notion of a (generalized) cell Helly
complex.
| arxiv topic:math.GR math.AT math.GT |
arxiv_dataset-111421904.0916 | Laminar-turbulent coexistence in annular Couette flow
physics.flu-dyn
Annular Couette flow is the flow between two coaxial cylinders driven by the
axial translation of the inner cylinder. It is investigated using direct
numerical simulation in long domains, with an emphasis on the laminar-turbulent
coexistence regime found for marginally low values of the Reynolds number.
Three distinct flow regimes are demonstrated as the radius ratio $\eta$ is
decreased from 0.8 to 0.5 and finally to 0.1. The high-$\eta$ regime features
helically-shaped turbulent patches coexisting with laminar flow, as in planar
shear flows. The moderate-$\eta$ regime does not feature any marked
laminar-turbulent coexistence. In an effort to discard confinement effects,
proper patterning is however recovered by artificially extending the azimuthal
span beyond 2$\pi$. Eventually, the low-$\eta$ regime features localised
turbulent structures different from the puffs commonly encountered in
transitional pipe flow. In this new coexistence regime, turbulent fluctuations
are surprisingly short-ranged. Implications are discussed in terms of phase
transition and critical scaling.
| arxiv topic:physics.flu-dyn |
arxiv_dataset-111431904.0926 | How does the photon's spin affect Gravitational Wave measurements?
gr-qc
We study the effect of the polarization of light beams on the time delay
measured in Gravitational Wave experiments. To this end, we consider the
Mathisson-Papapetrou-Dixon equations in a gravitational wave background, with
two of the possible spin supplementary conditions: by Frenkel-Pirani, or by
Tulczyjew. In the first case, photons follow a null geodesic and thus no spin
effect is present. The second case shows a deviation of the photons from the
null geodesic, resulting in a tiny effect on the measured time delay of photons
depending on their polarization state.
| arxiv topic:gr-qc |
arxiv_dataset-111441904.0936 | StegoAppDB: a Steganography Apps Forensics Image Database
eess.IV cs.MM
In this paper, we present a new reference dataset simulating digital evidence
for image steganography. Steganography detection is a digital image forensic
topic that is relatively unknown in practical forensics, although stego app use
in the wild is on the rise. This paper introduces the first database consisting
of mobile phone photographs and stego images produced from mobile stego apps,
including a rich set of side information, offering simulated digital evidence.
StegoAppDB, a steganography apps forensics image database, contains over
810,000 innocent and stego images using a minimum of 10 different phone models
from 24 distinct devices, with detailed provenanced data comprising a wide
range of ISO and exposure settings, EXIF data, message information, embedding
rates, etc. We develop a camera app, Cameraw, specifically for data
acquisition, with multiple images per scene, saving simultaneously in both DNG
and high-quality JPEG formats. Stego images are created from these original
images using selected mobile stego apps through a careful process of reverse
engineering. StegoAppDB contains cover-stego image pairs including for apps
that resize the stego dimensions. We retainthe original devices and continue to
enlarge the database, and encourage the image forensics community to use
StegoAppDB. While designed for steganography, we discuss uses of this publicly
available database to other digital image forensic topics.
| arxiv topic:eess.IV cs.MM |
arxiv_dataset-111451904.0946 | Data-Driven Neuron Allocation for Scale Aggregation Networks
cs.CV
Successful visual recognition networks benefit from aggregating information
spanning from a wide range of scales. Previous research has investigated
information fusion of connected layers or multiple branches in a block, seeking
to strengthen the power of multi-scale representations. Despite their great
successes, existing practices often allocate the neurons for each scale
manually, and keep the same ratio in all aggregation blocks of an entire
network, rendering suboptimal performance. In this paper, we propose to learn
the neuron allocation for aggregating multi-scale information in different
building blocks of a deep network. The most informative output neurons in each
block are preserved while others are discarded, and thus neurons for multiple
scales are competitively and adaptively allocated. Our scale aggregation
network (ScaleNet) is constructed by repeating a scale aggregation (SA) block
that concatenates feature maps at a wide range of scales. Feature maps for each
scale are generated by a stack of downsampling, convolution and upsampling
operations. The data-driven neuron allocation and SA block achieve strong
representational power at the cost of considerably low computational
complexity. The proposed ScaleNet, by replacing all 3x3 convolutions in ResNet
with our SA blocks, achieves better performance than ResNet and its outstanding
variants like ResNeXt and SE-ResNet, in the same computational complexity. On
ImageNet classification, ScaleNets absolutely reduce the top-1 error rate of
ResNets by 1.12 (101 layers) and 1.82 (50 layers). On COCO object detection,
ScaleNets absolutely improve the mmAP with backbone of ResNets by 3.6 (101
layers) and 4.6 (50 layers) on Faster RCNN, respectively. Code and models are
released at https://github.com/Eli-YiLi/ScaleNet.
| arxiv topic:cs.CV |
arxiv_dataset-111461904.0956 | On the size of subsets of $\mathbb{F}_p^{n}$ without $p$ distinct
elements summing to zero
math.CO math.NT
Let us fix a prime $p$. The Erd\H{o}s-Ginzburg-Ziv problem asks for the
minimum integer $s$ such that any collection of $s$ points in the lattice
$\mathbb{Z}^n$ contains $p$ points whose centroid is also a lattice point in
$\mathbb{Z}^n$. For large $n$, this is essentially equivalent to asking for the
maximum size of a subset of $\mathbb{F}_p^n$ without $p$ distinct elements
summing to zero.
In this paper, we give a new upper bound for this problem for any fixed prime
$p\geq 5$ and large $n$. In particular, we prove that any subset of
$\mathbb{F}_p^n$ without $p$ distinct elements summing to zero has size at most
$C_p\cdot \left(2\sqrt{p}\right)^n$, where $C_p$ is a constant only depending
on $p$. For $p$ and $n$ going to infinity, our bound is of the form
$p^{(1/2)\cdot (1+o(1))n}$, whereas all previously known upper bounds were of
the form $p^{(1-o(1))n}$ (with $p^n$ being a trivial bound).
Our proof uses the so-called multi-colored sum-free theorem which is a
consequence of the Croot-Lev-Pach polynomial method. This method and its
consequences were already applied by Naslund as well as by Fox and the author
to prove bounds for the problem studied in this paper. However, using some key
new ideas, we significantly improve their bounds.
| arxiv topic:math.CO math.NT |
arxiv_dataset-111471904.0966 | Accelerating Black Hole Chemistry
hep-th gr-qc
We introduce a new set of chemical variables for the accelerating black hole.
We show how these expressions suggest that conical defects emerging from a
black hole can be considered as true hair -- a new charge that the black hole
can carry -- and discuss the impact of conical deficits on black hole
thermodynamics from this `chemical' perspective. We conclude by proving a new
{\it Reverse Isoperimetric Inequality} for black holes with conical defects.
| arxiv topic:hep-th gr-qc |
arxiv_dataset-111481904.0976 | Invariants of PSL(n,R)-Fuchsian representations and a slice of Hitchin
components
math.GT
In this paper we show some properties of triangle invariants and shearing
invariants of PSL(n,R)-Fuchsian representations. Moreover, using the
Bonahon-Dreyer parameterization, we show that the Fuchsian locus of Hitchin
components corresponds to a slice.
| arxiv topic:math.GT |
arxiv_dataset-111491904.0986 | Learning Manipulation under Physics Constraints with Visual Perception
cs.RO
Understanding physical phenomena is a key competence that enables humans and
animals to act and interact under uncertain perception in previously unseen
environments containing novel objects and their configurations. In this work,
we consider the problem of autonomous block stacking and explore solutions to
learning manipulation under physics constraints with visual perception inherent
to the task. Inspired by the intuitive physics in humans, we first present an
end-to-end learning-based approach to predict stability directly from
appearance, contrasting a more traditional model-based approach with explicit
3D representations and physical simulation. We study the model's behavior
together with an accompanied human subject test. It is then integrated into a
real-world robotic system to guide the placement of a single wood block into
the scene without collapsing existing tower structure. To further automate the
process of consecutive blocks stacking, we present an alternative approach
where the model learns the physics constraint through the interaction with the
environment, bypassing the dedicated physics learning as in the former part of
this work. In particular, we are interested in the type of tasks that require
the agent to reach a given goal state that may be different for every new
trial. Thereby we propose a deep reinforcement learning framework that learns
policies for stacking tasks which are parametrized by a target structure.
| arxiv topic:cs.RO |
arxiv_dataset-111501904.0996 | Strong Structural Controllability of Networks under Time-Invariant and
Time-Varying Topological Perturbations
math.DS math.OC
This paper investigates the robustness of strong structural controllability
for linear time-invariant and linear time-varying directed networks with
respect to structural perturbations, including edge deletions and additions. In
this direction, we introduce a new construct referred to as a perfect graph
associated with a network with a given set of control nodes. The tight upper
bounds on the number of edges that can be added to, or removed from a network,
while ensuring strong structural controllability, are then derived. Moreover,
we obtain a characterization of critical edge-sets, the maximal sets of edges
whose any subset can be respectively added to, or removed from a network, while
preserving strong structural controllability. In addition, procedures for
combining networks to obtain strongly structurally controllable
network-of-networks are proposed. Finally, controllability conditions are
proposed for networks whose edge weights, as well as their structures, can vary
over time.
| arxiv topic:math.DS math.OC |
arxiv_dataset-111511904.1006 | Centers of subgroups of big mapping class groups and the Tits
alternative
math.GT math.GR
In this note we show that many subgroups of mapping class groups of
infinite-type surfaces without boundary have trivial centers, including all
normal subgroups. Using similar techniques, we show that every nontrivial
normal subgroup of a big mapping class group contains a nonabelian free group.
In contrast, we show that no big mapping class group satisfies the strong Tits
alternative enjoyed by finite-type mapping class groups. We also give examples
of big mapping class groups that fail to satisfy even the classical Tits
alternative and give a proof that every countable group appears as a subgroup
of some big mapping class group.
| arxiv topic:math.GT math.GR |
arxiv_dataset-111521904.1016 | Migration patterns under different scenarios of sea level rise
cs.CY
We propose a framework to examine future migration patterns of people under
different sea level rise scenarios using models of human migration.
Specifically, we couple a sea level rise model with a data-driven model of
human migration, creating a generalized joint model of climate driven migration
that can be used to simulate population distributions under potential future
sea level rise scenarios. We show how this joint model relaxes assumptions in
existing efforts to model climate driven human migration, and use it to
simulate how migration, driven by sea level rise, differs from baseline
migration patterns. Our results show that the effects of sea level rise are
pervasive, expanding beyond coastal areas via increased migration, and
disproportionately affecting some areas of the United States. The code for
reproducing this study is available at
https://github.com/calebrob6/migration-slr.
| arxiv topic:cs.CY |
arxiv_dataset-111531904.1026 | Two variable fragment of Term Modal Logic
cs.LO
Term modal logics (TML) are modal logics with unboundedly many modalities,
with quantification over modal indices, so that we can have formulas of the
form $\exists y. \forall x. (\Box_x P(x,y) \supset\Diamond_y P(y,x))$. Like
First order modal logic, TML is also "notoriously" undecidable, in the sense
that even very simple fragments are undecidable. In this paper, we show the
decidability of one interesting fragment, that of two variable TML. This is in
contrast to two-variable First order modal logic, which is undecidable.
| arxiv topic:cs.LO |
arxiv_dataset-111541904.1036 | Polarization, sign sequences and isotropic vector systems
math.MG math.CA
We determine the order of magnitude of the $n$th $\ell_p$-polarization
constant of the unit sphere $S^{d-1}$ for every $n,d \geq 1$ and $p>0$. For
$p=2$, we prove that extremizers are isotropic vector sets, whereas for $p=1$,
we show that the polarization problem is equivalent to that of maximizing the
norm of signed vector sums. Finally, for $d=2$, we discuss the optimality of
equally spaced configurations on the unit circle.
| arxiv topic:math.MG math.CA |
arxiv_dataset-111551904.1046 | Dimensional crossover in a layered ferromagnet detected by spin
correlation driven distortions
cond-mat.mes-hall cond-mat.str-el
Magneto-elastic distortions are commonly detected across magnetic long-range
ordering (LRO) transitions. In principle, they are also induced by the magnetic
short-range ordering (SRO) that precedes a LRO transition, which contains
information about short-range correlations and energetics that are essential
for understanding how LRO is established. However these distortions are
difficult to resolve because the associated atomic displacements are
exceedingly small and do not break symmetry. Here we demonstrate high-multipole
nonlinear optical polarimetry as a sensitive and mode selective probe of SRO
induced distortions using CrSiTe$_3$ as a testbed. This compound is composed of
weakly bonded sheets of nearly isotropic ferromagnetically interacting spins
that, in the Heisenberg limit, would individually be impeded from LRO by the
Mermin-Wagner theorem. Our results show that CrSiTe$_3$ evades this law via a
two-step crossover from two- to three-dimensional magnetic SRO, manifested
through two successive and previously undetected totally symmetric distortions
above its Curie temperature.
| arxiv topic:cond-mat.mes-hall cond-mat.str-el |
arxiv_dataset-111561904.1056 | Cold, old and metal-poor: New stellar substructures in the Milky Way's
dwarf spheroidals
astro-ph.GA
Dwarf spheroidal galaxies (dSph) orbiting the Milky Way are complex objects
often with complicated star formation histories and internal dynamics. In this
work, we search for stellar substructures in four of the classical dSph
satellites of the Milky Way: Sextans, Carina, Leo I, and Leo II. We apply two
methods to search for stellar substructure: the minimum spanning tree method,
which helps us to find and quantify spatially connected structures, and the
"brute-force" method, which is able to find elongated stellar substructures. We
detected the previously known substructure in Sextans, and also found a new
stellar substructure within Sextans. Furthermore, we identified a new stellar
substructure close to the core radius of the Carina dwarf galaxy. We report a
detection of one substructure in Leo I and two in Leo II, but we note that we
are dealing with a low number of stars in the samples used. Such old stellar
substructures in dSph galaxies could help us to shed light on the nature of the
dark matter halos, within which such structures form, evolve, and survive.
| arxiv topic:astro-ph.GA |
arxiv_dataset-111571904.1066 | Unbiased truncated quadratic variation for volatility estimation in jump
diffusion processes
math.ST stat.TH
The problem of integrated volatility estimation for the solution X of a
stochastic differential equation with L{\'e}vy-type jumps is considered under
discrete high-frequency observations in both short and long time horizon. We
provide an asymptotic expansion for the integrated volatility that gives us, in
detail, the contribution deriving from the jump part. The knowledge of such a
contribution allows us to build an unbiased version of the truncated quadratic
variation, in which the bias is visibly reduced. In earlier results the
condition $\beta$ > 1 2(2--$\alpha$) on $\beta$ (that is such that (1/n)
$\beta$ is the threshold of the truncated quadratic variation) and on the
degree of jump activity $\alpha$ was needed to have the original truncated
realized volatility well-performed (see [22], [13]). In this paper we
theoretically relax this condition and we show that our unbiased estimator
achieves excellent numerical results for any couple ($\alpha$, $\beta$).
L{\'e}vy-driven SDE, integrated variance, threshold estimator, convergence
speed, high frequency data.
| arxiv topic:math.ST stat.TH |
arxiv_dataset-111581904.1076 | End-to-End Spoken Language Translation
cs.CL cs.SD eess.AS
In this paper, we address the task of spoken language understanding. We
present a method for translating spoken sentences from one language into spoken
sentences in another language. Given spectrogram-spectrogram pairs, our model
can be trained completely from scratch to translate unseen sentences. Our
method consists of a pyramidal-bidirectional recurrent network combined with a
convolutional network to output sentence-level spectrograms in the target
language. Empirically, our model achieves competitive performance with
state-of-the-art methods on multiple languages and can generalize to unseen
speakers.
| arxiv topic:cs.CL cs.SD eess.AS |
arxiv_dataset-111591904.1086 | Higher Deformations of Lie Algebra Representations II
math.RT math.GR math.RA
Steinberg's tensor product theorem shows that for semisimple algebraic groups
the study of irreducible representations of higher Frobenius kernels reduces to
the study of irreducible representations of the first Frobenius kernel. In the
preceding paper in this series, deforming the distribution algebra of a higher
Frobenius kernel yielded a family of deformations called higher reduced
enveloping algebras. In this paper we prove that Steinberg decomposition can be
similarly deformed, allowing us to reduce representation theoretic questions
about these algebras to questions about reduced enveloping algebras. We use
this to derive structural results about modules over these algebras.
Separately, we also show that many of the results in the preceding paper hold
without an assumption of reductivity.
| arxiv topic:math.RT math.GR math.RA |
arxiv_dataset-111601904.1096 | The utility of a convolutional neural network for generating a myelin
volume index map from rapid simultaneous relaxometry imaging
eess.IV cs.AI
Background and Purpose: A current algorithm to obtain a synthetic myelin
volume fraction map (SyMVF) from rapid simultaneous relaxometry imaging (RSRI)
has a potential problem, that it does not incorporate information from
surrounding pixels. The purpose of this study was to develop a method that
utilizes a convolutional neural network (CNN) to overcome this problem.
Methods: RSRI and magnetization transfer images from 20 healthy volunteers were
included. A CNN was trained to reconstruct RSRI-related metric maps into a
myelin volume-related index (generated myelin volume index: GenMVI) map using
the myelin volume index map calculated from magnetization transfer images
(MTMVI) as reference. The SyMVF and GenMVI maps were statistically compared by
testing how well they correlated with the MTMVI map. The correlations were
evaluated based on: (i) averaged values obtained from 164 atlas-based ROIs, and
(ii) pixel-based comparison for ROIs defined in four different tissue types
(cortical and subcortical gray matter, white matter, and whole brain). Results:
For atlas-based ROIs, the overall correlation with the MTMVI map was higher for
the GenMVI map than for the SyMVF map. In the pixel-based comparison,
correlation with the MTMVI map was stronger for the GenMVI map than for the
SyMVF map, and the difference in the distribution for the volunteers was
significant (Wilcoxon sign-rank test, P<.001) in all tissue types. Conclusion:
The proposed method is useful, as it can incorporate more specific information
about local tissue properties than the existing method.
| arxiv topic:eess.IV cs.AI |
arxiv_dataset-111611904.1106 | Normal Approximation in Large Network Models
econ.EM math.ST stat.TH
We prove a central limit theorem for network formation models with strategic
interactions and homophilous agents. Since data often consists of observations
on a single large network, we consider an asymptotic framework in which the
network size diverges. We argue that a modification of ``stabilization''
conditions from the literature on geometric graphs provides a useful high-level
formulation of weak dependence, which we utilize to establish an abstract
central limit theorem. In the context of strategic network formation, we derive
primitive conditions for stabilization using results in branching process
theory. We outline a methodology for deriving primitive conditions that can be
applied more broadly to other large network models with strategic interactions.
Finally, we discuss practical inference procedures justified by our results.
| arxiv topic:econ.EM math.ST stat.TH |
arxiv_dataset-111621904.1116 | Silver Amalgam Nanoparticles and Microparticles: A Novel Plasmonic
Platform for Spectroelectrochemistry
physics.optics cond-mat.mtrl-sci
Plasmonic nanoparticles from unconventional materials can improve or even
bring some novel functionalities into the disciplines inherently related to
plasmonics such as photochemistry or (spectro)electrochemistry. They can, for
example, catalyze various chemical reactions or act as nanoelectrodes and
optical transducers in various applications. Silver amalgam is the perfect
example of such an unconventional plasmonic material, albeit it is well-known
in the field of electrochemistry for its wide cathodic potential window and
strong adsorption affinity of biomolecules to its surface. In this study, we
investigate in detail the optical properties of nanoparticles and
microparticles made from silver amalgam and correlate their plasmonic
resonances with their morphology. We use optical spectroscopy techniques on the
ensemble level and electron energy loss spectroscopy on the single-particle
level to demonstrate the extremely wide spectral range covered by the silver
amalgam localized plasmonic resonances, ranging from ultraviolet all the way to
the mid-infrared wavelengths. Our results establish silver amalgam as a
suitable material for introduction of plasmonic functionalities into
photochemical and spectroelectrochemical systems, where the plasmonic
enhancement of electromagnetic fields and light emission processes could
synergistically meet with the superior electrochemical characteristics of
mercury.
| arxiv topic:physics.optics cond-mat.mtrl-sci |
arxiv_dataset-111631904.1126 | Vacuum expectation value of the energy-momentum tensor in a higher
dimensional compactified cosmic string spacetime
hep-th gr-qc
The main objective of this paper is to analyze the vacuum expectation value
(VEV) of the energy-momentum tensor (EMT) associated with a charged scalar
quantum field in a high-dimensional cosmic string spacetime admitting the
presence of a magnetic flux running along the string's core. In addition, we
also assume that the coordinate along the string's axis is compactified to a
circle and presents an extra magnetic flux running along its center. This
compactification is implemented by imposing a quasiperiodic condition on the
field with an arbitrary phase $\beta$. The calculation of the VEV of the EMT
and field squared, are developed by using the positive-energy Wightman
function. The latter is constructed by the mode sum of the complete set of
normalized bosonic wave-functions. Due to the compactification, two distinct
contributions take place. The first one corresponds to the VEV in a cosmic
string spacetime without compactification considering the magnetic interaction.
So, this term presents a contribution due to the non-trivial topology of the
conical space, and an additional contribution due to the interaction between
the scalar field with the magnetic flux. The latter is a periodic function of
the magnetic flux with period equal to the quantum flux, $\Phi_0=2\pi/e$, and
corresponds to a Aharanov-Bhom type contribution. The second contribution is
induced by the compactification itself and depends on the magnetic flux along
the string's core. It is also an even function of the magnetic flux enclosed by
the string axis. Some asymptotic expressions for the VEVs of the
energy-momentum tensor and field squared are provided for specific limiting
cases of the physical parameter of the model.
| arxiv topic:hep-th gr-qc |
arxiv_dataset-111641904.1136 | Observations of CH$_3$OH and CH$_3$CHO in a Sample of Protostellar
Outflow Sources
astro-ph.GA
Iram 30-m Observations towards eight protostellar outflow sources were taken
in the 96-\SI{176}{\giga\hertz} range. Transitions of CH$_3$OH and CH$_3$CHO
were detected in seven of them. The integrated emission of the transitions of
each species that fell into the observed frequency range were measured and fit
using RADEX and LTE models. Column densities and gas properties inferred from
this fitting are presented. The ratio of the A and E-type isomers of CH$_3$OH
indicate that the methanol observed in these outflows was formed on the grain
surface. Both species demonstrate a reduction of terminal velocity in their
line profiles in faster outflows, indicating destruction in the post-shock gas
phase. This destruction, and a near constant ratio of the CH$_3$OH and
CH$_3$CHO column densities imply it is most likely that CH$_3$CHO also forms on
the grain surface.
| arxiv topic:astro-ph.GA |
arxiv_dataset-111651904.1146 | Constructing cocyclic Hadamard matrices of order 4p
math.CO math.GR
Cocyclic Hadamard matrices (CHMs) were introduced by de Launey and Horadam as
a class of Hadamard matrices with interesting algebraic properties. \'O
Cath\'ain and R\"oder described a classification algorithm for CHMs of order
$4n$ based on relative difference sets in groups of order $8n$; this led to the
classification of all CHMs of order at most 36. Based on work of de Launey and
Flannery, we describe a classification algorithm for CHMs of order $4p$ with
$p$ a prime; we prove refined structure results and provide a classification
for $p \leqslant 13$. Our analysis shows that every CHM of order $4p$ with
$p\equiv 1\bmod 4$ is equivalent to a Hadamard matrix with one of five distinct
block structures, including Williamson type and (transposed) Ito matrices. If
$p\equiv 3 \bmod 4$, then every CHM of order $4p$ is equivalent to a Williamson
type or (transposed) Ito matrix.
| arxiv topic:math.CO math.GR |
arxiv_dataset-111661904.1156 | A Survey on Tiering and Caching in High-Performance Storage Systems
cs.AR cs.OS
Although every individual invented storage technology made a big step towards
perfection, none of them is spotless. Different data store essentials such as
performance, availability, and recovery requirements have not met together in a
single economically affordable medium, yet. One of the most influential factors
is price. So, there has always been a trade-off between having a desired set of
storage choices and the costs. To address this issue, a network of various
types of storing media is used to deliver the high performance of expensive
devices such as solid state drives and non-volatile memories, along with the
high capacity of inexpensive ones like hard disk drives. In software, caching
and tiering are long-established concepts for handling file operations and
moving data automatically within such a storage network and manage data backup
in low-cost media. Intelligently moving data around different devices based on
the needs is the key insight for this matter. In this survey, we discuss some
recent pieces of research that have been done to improve high-performance
storage systems with caching and tiering techniques.
| arxiv topic:cs.AR cs.OS |
arxiv_dataset-111671904.1166 | Transformers with convolutional context for ASR
cs.CL
The recent success of transformer networks for neural machine translation and
other NLP tasks has led to a surge in research work trying to apply it for
speech recognition. Recent efforts studied key research questions around ways
of combining positional embedding with speech features, and stability of
optimization for large scale learning of transformer networks. In this paper,
we propose replacing the sinusoidal positional embedding for transformers with
convolutionally learned input representations. These contextual representations
provide subsequent transformer blocks with relative positional information
needed for discovering long-range relationships between local concepts. The
proposed system has favorable optimization characteristics where our reported
results are produced with fixed learning rate of 1.0 and no warmup steps. The
proposed model achieves a competitive 4.7% and 12.9% WER on the Librispeech
``test clean'' and ``test other'' subsets when no extra LM text is provided.
| arxiv topic:cs.CL |
arxiv_dataset-111681904.1176 | Induction of chaotic fluctuations in particle dynamics in a uniformly
accelerated frame
gr-qc astro-ph.GA hep-th nlin.CD
The ongoing conjecture that the presence of horizon may induce chaos in an
integrable system, is further investigated from the perspective of a uniformly
accelerated frame. Particularly, we build up a model which consists of a
particle (massless and chargeless) trapped in harmonic oscillator in a
uniformly accelerated frame (namely Rindler observer). Here the Rindler frame
provides a Killing horizon without any intrinsic curvature to the system. This
makes the present observations different from previous studies. We observe that
for some particular values of parameters of the system (like acceleration,
energy of the particle), the motion of the particle trapped in harmonic
potential systematically goes from periodic state to the chaotic. This
indicates that the existence of horizon alone, not the intrinsic curvature
(i.e. the gravitational effect) in the background, is sufficient to induce the
chaotic motion in the particle. We believe the present study further enlighten
and balustrade the conjecture.
| arxiv topic:gr-qc astro-ph.GA hep-th nlin.CD |
arxiv_dataset-111691904.1186 | Approximation of Riemannian Distances and Applications to Distance-Based
Learning on Manifolds
math.DG
Several important algorithms for machine learning and data analysis use
pairwise distances as input. On Riemannian manifolds these distances may be
prohibitively costly to compute, in particular for large datasets. To tackle
this problem, we propose a distance approximation which requires only a linear
number of geodesic boundary value problems to be solved. The approximation is
constructed by fitting a two-dimensional model space with constant curvature to
each pair of samples. We demonstrate the usefulness of our approach in the
context of shape analysis on landmarks spaces.
| arxiv topic:math.DG |
arxiv_dataset-111701904.1196 | Lifting AutoEncoders: Unsupervised Learning of a Fully-Disentangled 3D
Morphable Model using Deep Non-Rigid Structure from Motion
cs.CV
In this work we introduce Lifting Autoencoders, a generative 3D surface-based
model of object categories. We bring together ideas from non-rigid structure
from motion, image formation, and morphable models to learn a controllable,
geometric model of 3D categories in an entirely unsupervised manner from an
unstructured set of images. We exploit the 3D geometric nature of our model and
use normal information to disentangle appearance into illumination, shading and
albedo. We further use weak supervision to disentangle the non-rigid shape
variability of human faces into identity and expression. We combine the 3D
representation with a differentiable renderer to generate RGB images and append
an adversarially trained refinement network to obtain sharp, photorealistic
image reconstruction results. The learned generative model can be controlled in
terms of interpretable geometry and appearance factors, allowing us to perform
photorealistic image manipulation of identity, expression, 3D pose, and
illumination properties.
| arxiv topic:cs.CV |
arxiv_dataset-111711904.1206 | Every planar graph with $\Delta\geqslant 8$ is totally
$(\Delta+2)$-choosable
cs.DM math.CO
Total coloring is a variant of edge coloring where both vertices and edges
are to be colored. A graph is totally $k$-choosable if for any list assignment
of $k$ colors to each vertex and each edge, we can extract a proper total
coloring. In this setting, a graph of maximum degree $\Delta$ needs at least
$\Delta+1$ colors. In the planar case, Borodin proved in 1989 that $\Delta+2$
colors suffice when $\Delta$ is at least 9. We show that this bound also holds
when $\Delta$ is $8$.
| arxiv topic:cs.DM math.CO |
arxiv_dataset-111721904.1216 | On the Feynman-Kac Formula
math.PR
In this article, given $y :[0,\eta)\rightarrow H$ a continuous map into a
Hilbert space $H$ we study the equation \[\hat y(t) = e^{\int_0^tc(s,\hat
y)}y(t)\] where $c(s,\cdot)$ is a given `potential' on $C([0,\eta),H)$.
Applying the transformation $y \rightarrow \hat y$ to the solutions of the SPDE
and PDE underlying a diffusion, we study the Feynman-Kac formula.
| arxiv topic:math.PR |
arxiv_dataset-111731904.1226 | Pricing and hedging of VIX options for Barndorff-Nielsen and Shephard
models
q-fin.MF
The VIX call options for the Barndorff-Nielsen and Shephard models will be
discussed. Derivatives written on the VIX, which is the most popular volatility
measurement, have been traded actively very much. In this paper, we give
representations of the VIX call option price for the Barndorff-Nielsen and
Shephard models: non-Gaussian Ornstein--Uhlenbeck type stochastic volatility
models. Moreover, we provide representations of the locally risk-minimizing
strategy constructed by a combination of the underlying riskless and risky
assets. Remark that the representations obtained in this paper are efficient to
develop a numerical method using the fast Fourier transform. Thus, numerical
experiments will be implemented in the last section of this paper.
| arxiv topic:q-fin.MF |
arxiv_dataset-111741904.1236 | Optimizing regularized Cholesky score for order-based learning of
Bayesian networks
stat.ML cs.LG
Bayesian networks are a class of popular graphical models that encode causal
and conditional independence relations among variables by directed acyclic
graphs (DAGs). We propose a novel structure learning method, annealing on
regularized Cholesky score (ARCS), to search over topological sorts, or
permutations of nodes, for a high-scoring Bayesian network. Our scoring
function is derived from regularizing Gaussian DAG likelihood, and its
optimization gives an alternative formulation of the sparse Cholesky
factorization problem from a statistical viewpoint, which is of independent
interest. We combine global simulated annealing over permutations with a fast
proximal gradient algorithm, operating on triangular matrices of edge
coefficients, to compute the score of any permutation. Combined, the two
approaches allow us to quickly and effectively search over the space of DAGs
without the need to verify the acyclicity constraint or to enumerate possible
parent sets given a candidate topological sort. The annealing aspect of the
optimization is able to consistently improve the accuracy of DAGs learned by
local search algorithms. In addition, we develop several techniques to
facilitate the structure learning, including pre-annealing data-driven tuning
parameter selection and post-annealing constraint-based structure refinement.
Through extensive numerical comparisons, we show that ARCS achieves substantial
improvements over existing methods, demonstrating its great potential to learn
Bayesian networks from both observational and experimental data.
| arxiv topic:stat.ML cs.LG |
arxiv_dataset-111751904.1246 | Theory of cyborg: a new approach to fish locomotion control
physics.bio-ph q-bio.NC q-bio.QM
Cyborg in the brain-machine interface field has attracted more attention in
recent years. To control a creature via a machine called cyborg method, three
stages are considerable: stimulation of neurons, neural response, and the
behavioral reaction of the subject. Our main concern was to know how electrical
stimulation induces neural activity and leads to a behavioral response.
Additionally, we were interested to explore which type of electrical
stimulation is optimal from different aspects such as maximum response with
minimum induction stimulus field, minimum damage of the tissue and the
electrode, reduction of the noxiousness of stimuli or pain in the living
creature. In this article, we proposed a new model for the induction of neural
activity led to locomotion responses through electrical stimulation.
Furthermore, based on this model, we developed a new approach of electrical
neural stimulation to provide a better locomotion control of living beings.
This approach was verified through the empirical data of fish cyborg. We
stimulated the fish brain by use of an ultra-high frequency signal which
careered by a random low frequency. According to our model, we could control
the locomotion of fish in a novel and innovative way. In this study, we
categorized the different cyborg methods based on the nervous system areas and
the stimulation signal properties to reach the better and optimal behavioral
control of creature. According to this, we proposed a new stimulation method
theoretically and confirmed it experimentally.
| arxiv topic:physics.bio-ph q-bio.NC q-bio.QM |
arxiv_dataset-111761904.1256 | Measurement of the Helicity Asymmetry $E$ for the reaction $ \gamma p\to
\pi^0 p$
nucl-ex
A measurement of the double-polarization observable $E$ for the reaction
$\gamma p\to \pi^0 p$ is reported. The data were taken with the CBELSA/TAPS
experiment at the ELSA facility in Bonn using the Bonn frozen-spin butanol
(C$_4$H$_9$OH) target, which provided longitudinally-polarized protons.
Circularly-polarized photons were produced via bremsstrahlung of
longitudinally-polarized electrons. The data cover the photon energy range from
$E_\gamma =600$~MeV to $E_\gamma =2310$~MeV and nearly the complete angular
range. The results are compared to and have been included in recent partial
wave analyses.
| arxiv topic:nucl-ex |
arxiv_dataset-111771904.1266 | Tracking Performance Limitations of MIMO Networked Control Systems with
Multiple Communication Constraints
cs.SY cs.PF
In this paper, the tracking performance limitation of networked control
systems (NCSs) is studied. The NCSs is considered as continuous-time linear
multi-input multi-output (MIMO) systems with random reference noises. The
controlled plants include unstable poles and non-minimum phase (NMP) zeros. The
output feedback path is affected by multiple communication constraints. We
focus on some basic communication constraints, including additive white noise
(AWN), quantization noise, bandwidth, as well as encoder-decoder. The system
performance is evaluated with the tracking error energy, and used a two-degree
of freedom (2DOF) controller. The explicit representation of the tracking
performance is given in this paper. The results indicate the tracking
performance limitations rely to internal characteristics of the plant (unstable
poles and NMP zeros), reference noises (the reference noise power distribution
(RNPD) and its directions) and the characteristics of communication
constraints. Moreover, the tracking performance limitations are also affected
by the angles between the each transform NMP zero direction and RNPD direction,
and these angles between each transform unstable poles direction and the
direction of communication constraint distribution/allocation. In addition, for
MIMO NCSs, bandwidth (there are not identical two channels) always can affects
the direction of unstable poles, and the channel allocation of bandwidth and
encode-decode may be used for a feasible method for the performance allocation
of each channels. Lastly, a instance is given for verifying the effectiveness
of the theoretical outcomes.
| arxiv topic:cs.SY cs.PF |
arxiv_dataset-111781904.1276 | Progressive Differentiable Architecture Search: Bridging the Depth Gap
between Search and Evaluation
cs.CV cs.LG
Recently, differentiable search methods have made major progress in reducing
the computational costs of neural architecture search. However, these
approaches often report lower accuracy in evaluating the searched architecture
or transferring it to another dataset. This is arguably due to the large gap
between the architecture depths in search and evaluation scenarios. In this
paper, we present an efficient algorithm which allows the depth of searched
architectures to grow gradually during the training procedure. This brings two
issues, namely, heavier computational overheads and weaker search stability,
which we solve using search space approximation and regularization,
respectively. With a significantly reduced search time (~7 hours on a single
GPU), our approach achieves state-of-the-art performance on both the proxy
dataset (CIFAR10 or CIFAR100) and the target dataset (ImageNet). Code is
available at https://github.com/chenxin061/pdarts.
| arxiv topic:cs.CV cs.LG |
arxiv_dataset-111791904.1286 | Morphology and star formation in IllustrisTNG: the build-up of spheroids
and discs
astro-ph.GA astro-ph.CO
Using the IllustrisTNG simulations, we investigate the connection between
galaxy morphology and star formation in central galaxies with stellar masses in
the range $10^9-10^{11.5}~\mathrm{M}_{\odot}$. We quantify galaxy morphology by
a kinematical decomposition of the stellar component into a spheroidal and a
disc component (spheroid-to-total ratio, S/T) and by the concentration of the
stellar mass density profile ($C_{82}$). S/T is correlated with stellar mass
and star-formation activity, while $C_{82}$ correlates only with stellar mass.
Overall, we find good agreement with observational estimates for both S/T and
$C_{82}$. Low and high mass galaxies are dominated by random stellar motion,
while only intermediate-mass galaxies
($M_{\star}\approx10^{10}-10^{10.5}~\mathrm{M}_{\odot}$) are dominated by
ordered rotation. Whereas higher-mass galaxies are typical spheroids with high
concentrations, lower-mass galaxies have low concentration, pointing to
different formation channels. Although we find a correlation between S/T and
star-formation activity, in the TNG model galaxies do not necessarily change
their morphology when they transition through the green valley or when they
cease their star formation, this depending on galaxy stellar mass and
morphological estimator. Instead, the morphology (S/T and $C_{82}$) is
generally set during the star-forming phase of galaxies. The apparent
correlation between S/T and star formation arises because earlier-forming
galaxies had, on average, a higher S/T at a given stellar mass. Furthermore, we
show that mergers drive in-situ bulge formation in intermediate-mass galaxies
and are responsible for the recent spheroidal mass assembly in the massive
galaxies with $M_{\star}>10^{11}~\mathrm{M}_{\odot}$. In particular, these
massive galaxies assemble about half of the spheroidal mass while star-forming
and the other half through mergers while quiescent.
| arxiv topic:astro-ph.GA astro-ph.CO |
arxiv_dataset-111801904.1296 | Modelling Diffuse Subcellular Protein Structures as Dynamic Social
Networks
q-bio.SC
Fluorescence microscopy has led to impressive quantitative models and new
insights gained from richer sets of biomedical imagery. However, there is a
dearth of rigorous and established bioimaging strategies for modeling
spatiotemporal behavior of diffuse, subcellular components such as mitochondria
or actin. In many cases, these structures are assessed by hand or with other
semi-quantitative measures. We propose to build descriptive and dynamic models
of diffuse subcellular morphologies, using the mitochondrial protein patterns
of cervical epithelial (HeLa) cells. We develop a parametric representation of
the patterns as a mixture of probability masses. This mixture is iteratively
perturbed over time to fit the evolving spatiotemporal behavior of the
subcellular structures. We convert the resulting trajectory into a series of
graph Laplacians to formally define a dynamic network. Finally, we demonstrate
how graph theoretic analyses of the trajectories yield biologically-meaningful
quantifications of the structures.
| arxiv topic:q-bio.SC |
arxiv_dataset-111811904.1306 | On the change of old neutron star masses with galactocentric distance
gr-qc astro-ph.HE hep-ph nucl-th
We show that the pulsar mass depends on the environment, and that it
decreases going towards the center of the Milky Way. This is due to two
combined effects, the capture and accumulation of self-interacting,
non-annihilating dark matter by pulsars, and the increase of the dark matter
density going towards the galactic center. We show that mass decrease depends
both on the density profile of dark matter, steeper profiles producing a faster
and larger decrease of the pulsar mass, and on the strength of
self-interaction. Once future observations will provide the pulsar mass in a
dark matter rich environment, close to the galactic center, the present result
will be able to put constraints on the characteristics of our Galaxy halo dark
matter profile, on the nature of dark matter, namely on its annihilating or
non-annihilating nature, on its strength of self-interaction, and on the
particle mass.
| arxiv topic:gr-qc astro-ph.HE hep-ph nucl-th |
arxiv_dataset-111821904.1316 | Magnetism trends in doped Ce-Cu intermetallics in the vicinity of
quantum criticality: realistic Kondo lattice models based on dynamical
mean-field theory
cond-mat.mtrl-sci cond-mat.str-el
The quantum critical point (QCP) in the archetypical heavy-fermion compound
CeCu$_6$ doped by Au is described, accounting for the localized $4f$-electron
of Ce, using realistic electronic structure calculations combined with
dynamical mean-field theory (DMFT). Magnetism trends in
Ce(Cu$_{1-\epsilon}$Au$_\epsilon$)$_6$ are compared with those in Co-doped
CeCu$_{5}$, which resides on the non-ferromagnetic side of the composition
space of one of the earliest rare-earth permanent magnet compounds,
Ce(Co,Cu)$_5$. The construction of a realistic Doniach phase diagram shows that
the system crosses over a magnetic quantum critical point in the Kondo lattice
in $0.2<x<0.4$ of Ce(Cu$_{1-x}$Co$_x$)$_5$. Comparison between Au-doped
CeCu$_6$ and Co-doped CeCu$_5$ reveals that the swept region in the vicinity of
QCP for the latter thoroughly covers that of the former. The implications of
these trends on the coercivity of the bulk rare-earth permanent magnets are
discussed.
| arxiv topic:cond-mat.mtrl-sci cond-mat.str-el |
arxiv_dataset-111831904.1326 | How to avoid collisions in 3D-realizations for moving graphs
math.CO
If we parameterize the positions of all vertices of a given graph in the
plane such that distances between adjacent vertices are fixed, we obtain a
moving graph. An L-linkage is a realization of a moving graph in 3D-space, by
representing edges using horizontal bars and vertices by vertical sticks.
Vertical sticks are parallel revolute joints, while horizontal bars are links
connecting them. We give a sufficient condition for a moving graph to have a
collision-free L-linkage. Furthermore, we provide an algorithm guiding the
construction of such a linkage when the moving graph fulfills the sufficient
condition, via computing a height function for the edges (horizontal bars). In
particular, we prove that any Dixon-1 moving graph has a collision-free
L-linkage and no Dixon-2 moving graphs have collision-free L-linkages, where
Dixon-1 and Dixon-2 moving graphs are two classic families of moving graphs.
| arxiv topic:math.CO |
arxiv_dataset-111841904.1336 | Finite-Memory Strategies in POMDPs with Long-Run Average Objectives
cs.GT math.OC
Partially observable Markov decision processes (POMDPs) are standard models
for dynamic systems with probabilistic and nondeterministic behaviour in
uncertain environments. We prove that in POMDPs with long-run average
objective, the decision maker has approximately optimal strategies with finite
memory. This implies notably that approximating the long-run value is
recursively enumerable, as well as a weak continuity property of the value with
respect to the transition function.
| arxiv topic:cs.GT math.OC |
arxiv_dataset-111851905.00064 | Shadow of a black hole surrounded by dark matter
gr-qc
We consider a simple spherical model consisting of a Schwarzschild black hole
of mass $M$ and a dark matter of mass $\Delta M$ around it. The general formula
for the radius of black-hole shadow has been derived in this case. It is shown
that the change of the shadow is not negligible, once the effective radius of
the dark matter halo is of order $\sim \sqrt{3 M \Delta M}$. For this to
happen, for example, for the galactic black hole, the dark matter must be
concentrated near the black hole. For small deviations from the Schwarzschild
limit, the dominant contribution into the size of a shadow is due to the dark
matter under the photon sphere, but at larger deviations, the matter outside
the photon sphere cannot be ignored.
| arxiv topic:gr-qc |
arxiv_dataset-111861905.00164 | On a conditional inequality in Kolmogorov complexity and its
applications in communication complexity
cs.CC cs.IT math.IT
Romashchenko and Zimand~\cite{rom-zim:c:mutualinfo} have shown that if we
partition the set of pairs $(x,y)$ of $n$-bit strings into combinatorial
rectangles, then $I(x:y) \geq I(x:y \mid t(x,y)) - O(\log n)$, where $I$
denotes mutual information in the Kolmogorov complexity sense, and $t(x,y)$ is
the rectangle containing $(x,y)$. We observe that this inequality can be
extended to coverings with rectangles which may overlap. The new inequality
essentially states that in case of a covering with combinatorial rectangles,
$I(x:y) \geq I(x:y \mid t(x,y)) - \log \rho - O(\log n)$, where $t(x,y)$ is
any rectangle containing $(x,y)$ and $\rho$ is the thickness of the covering,
which is the maximum number of rectangles that overlap. We discuss applications
to communication complexity of protocols that are nondeterministic, or
randomized, or Arthur-Merlin, and also to the information complexity of
interactive protocols.
| arxiv topic:cs.CC cs.IT math.IT |
arxiv_dataset-111871905.00264 | The parameterization method for center manifolds
math.DS
In this paper, we present a generalization of the parameterization method,
introduced by Cabr\'{e}, Fontich and De la Llave, to center manifolds
associated to non-hyperbolic fixed points of discrete dynamical systems. As a
byproduct, we find a new proof for the existence and regularity of center
manifolds. However, in contrast to the classical center manifold theorem, our
parameterization method will simultaneously obtain the center manifold and its
conjugate center dynamical system. Furthermore, we will provide bounds on the
error between approximations of the center manifold and the actual center
manifold, as well as bounds for the error in the conjugate dynamical system.
| arxiv topic:math.DS |
arxiv_dataset-111881905.00364 | Matching for the Israeli "Mechinot" Gap-Year Programs: Handling Rich
Diversity Requirements
cs.GT econ.TH
We describe our experience with designing and running a matching market for
the Israeli "Mechinot" gap-year programs. The main conceptual challenge in the
design of this market was the rich set of diversity considerations, which
necessitated the development of an appropriate preference-specification
language along with corresponding choice-function semantics, which we also
theoretically analyze. Our contribution extends the existing toolbox for
two-sided matching with soft constraints. This market was run for the first
time in January 2018 and matched 1,607 candidates (out of a total of 3,120
candidates) to 35 different programs, has been run twice more since, and has
been adopted by the Joint Council of the "Mechinot" gap-year programs for the
foreseeable future.
| arxiv topic:cs.GT econ.TH |
arxiv_dataset-111891905.00464 | On Reflectivity of Quantum Black Hole Horizons
hep-th astro-ph.HE gr-qc
We study the reflectivity of quantum black hole (BH) horizons using detailed
balance and fluctuation-dissipation theorem, finding a universal flux
reflectivity given by the Boltzmann factor ${\mathcal R} = \exp\left(-{\hbar
|\omega| \over k T_{\rm H}}\right)$, where $\omega$ is frequency in the horizon
frame and $T_{\rm H}$ is the Hawking temperature. This implies CP-symmetry (or
$\bf{RP}^3$ topology) of the extended BH spacetime. We then briefly discuss
related physical implications: We predict echoes in the ringdown of Kerr BHs,
but they do not exhibit ergoregion instability. The viscosity in the membrane
paradigm is modified to $\eta = \frac{c^3}{16\pi G}\tanh\left({\hbar |\omega|
\over 4 k T_{\rm H}}\right)$, only approaching General Relativistic value at
high frequencies.
| arxiv topic:hep-th astro-ph.HE gr-qc |
arxiv_dataset-111901905.00564 | Hyperspaces $C(p,X)$ of finite graphs
math.GN
Given a continuum $X$ and $p\in X$, we will consider the hyperspace $C(p,X)$
of all subcontinua of $X$ containing $p$ and the family $K(X)$ of all
hyperspaces $C(q,X)$, where $q\in X$. In this paper we give some conditions on
the points $p,q\in X$ to guarantee that $C(p,X)$ and $C(q,X)$ are homeomorphic,
for finite graphs $X$. Also, we study the relationship between the homogeneity
degree of a finite graph $X$ and the number of topologically distinct spaces in
$K(X)$, called the size of $K(X)$. In addition, we construct for each positive
integer $n$, a finite graph $X_n$ such that $K(X_n)$ has size $n$, and we
present a theorem that allows to construct finite graphs $X$ with a degree of
homogeneity different from the size of the family $K(X)$.
| arxiv topic:math.GN |
arxiv_dataset-111911905.00664 | Spectroscopic Evaluation of Charge-transfer Doping and Strain in
Graphene/MoS2 Heterostructures
cond-mat.mes-hall physics.optics
It is important to study the van der Waals interface in emerging vertical
heterostructures based on layered two-dimensional (2D) materials. Being
atomically thin, 2D materials are susceptible to significant strains as well as
charge transfer doping across the interfaces. Here we use Raman and
photoluminescence (PL) spectroscopy to study the interface between monolayer
graphene/MoS2 heterostructures prepared by mechanical exfoliation and
layer-by-layer transfer. By using correlation analysis between the Raman modes
of graphene and MoS2 we show that both layers are subjected to compressive
strain and charge transfer doping following mechanical exfoliation and thermal
annealing. Furthermore, we show that both strain and carrier concentration can
be modulated in the heterostructures with additional thermal annealing. Our
study highlights the importance of considering both mechanical and electronic
coupling when characterizing the interface in van der Waals heterostructures,
and demonstrates a method to tune their electromechanical properties.
| arxiv topic:cond-mat.mes-hall physics.optics |
arxiv_dataset-111921905.00764 | Optomechanical measurement of thermal transport in two-dimensional MoSe2
lattices
cond-mat.mes-hall physics.optics
Nanomechanical resonators have emerged as sensors with exceptional
sensitivities. These sensing capabilities open new possibilities in the studies
of the thermodynamic properties in condensed matter. Here, we use mechanical
sensing as a novel approach to measure the thermal properties of
low-dimensional materials. We measure the temperature dependence of both the
thermal conductivity and the specific heat capacity of a transition metal
dichalcogenide (TMD) monolayer down to cryogenic temperature, something that
has not been achieved thus far with a single nanoscale object. These
measurements show how heat is transported by phonons in two-dimensional
systems. Both the thermal conductivity and the specific heat capacity
measurements are consistent with predictions based on first-principles.
| arxiv topic:cond-mat.mes-hall physics.optics |
arxiv_dataset-111931905.00864 | Elliptic Blowup Equations for 6d SCFTs. II: Exceptional Cases
hep-th math-ph math.MP
The building blocks of 6d $(1,0)$ SCFTs include certain rank one theories
with gauge group $G=SU(3),SO(8),F_4,E_{6,7,8}$. In this paper, we propose a
universal recursion formula for the elliptic genera of all such theories. This
formula is solved from the elliptic blowup equations introduced in our previous
paper. We explicitly compute the elliptic genera and refined BPS invariants,
which recover all previous results from topological string theory, modular
bootstrap, Hilbert series, 2d quiver gauge theories and 4d $\mathcal{N}=2$
superconformal $H_{G}$ theories. We also observe an intriguing relation between
the $k$-string elliptic genus and the Schur indices of rank $k$ $H_{G}$ SCFTs,
as a generalization of Lockhart-Zotto's conjecture at the rank one cases. In a
subsequent paper, we deal with all other non-Higgsable clusters with matters.
| arxiv topic:hep-th math-ph math.MP |
arxiv_dataset-111941905.00964 | A Survey of Moving Target Defenses for Network Security
cs.CR cs.NI
Network defenses based on traditional tools, techniques, and procedures fail
to account for the attacker's inherent advantage present due to the static
nature of network services and configurations. To take away this asymmetric
advantage, Moving Target Defense (MTD) continuously shifts the configuration of
the underlying system, in turn reducing the success rate of cyberattacks. In
this survey, we analyze the recent advancements made in the development of MTDs
and define categorizations that capture the key aspects of such defenses. We
first categorize these defenses into different sub-classes depending on what
they move, when they move and how they move. In trying to answer the latter
question, we showcase the use of domain knowledge and game-theoretic modeling
can help the defender come up with effective and efficient movement strategies.
Second, to understand the practicality of these defense methods, we discuss how
various MTDs have been implemented and find that networking technologies such
as Software Defined Networking and Network Function Virtualization act as key
enablers for implementing these dynamic defenses. We then briefly highlight MTD
test-beds and case-studies to aid readers who want to examine or deploy
existing MTD techniques. Third, our survey categorizes proposed MTDs based on
the qualitative and quantitative metrics they utilize to evaluate their
effectiveness in terms of security and performance. We use well-defined metrics
such as risk analysis and performance costs for qualitative evaluation and
metrics based on Confidentiality, Integrity, Availability (CIA), attack
representation, QoS impact, and targeted threat models for quantitative
evaluation. Finally, we show that our categorization of MTDs is effective in
identifying novel research areas and highlight directions for future research.
| arxiv topic:cs.CR cs.NI |
arxiv_dataset-111951905.01064 | Numerical study of the negative nonlocal resistance and the backflow
current in a ballistic graphene system
cond-mat.mes-hall
Besides the giant peak of the nonlocal resistance $R_{NL}$, an anomalous
negative value of $R_{NL}$ has been observed in graphene systems, while its
formation mechanism is not quite understood yet. In this work, utilizing the
non-equilibrium Green's function method, we calculate the local-current flow in
an H-shaped non-interacting graphene system locating in the ballistic regime.
Similar to the previous conclusions made from the viscous regime, the numerical
results show that a local-current vortex appears between the nonlocal measuring
terminals, which induces a backflow current and a remarkable negative voltage
drop at the probe. Specifically, the stronger the vortex exhibits, the more
negative $R_{NL}$ manifests. Besides, a spin-orbital coupling is added as an
additional tool to study this exotic vortex, which is not a driving force for
the arising vortex at all. Moreover, a breakdown of the nonlocal
Wiedemann-Franz law is obtained in this ballistic system, and two experimental
criteria are further provided to confirm the existence of this exotic vortex.
Notably, a discussion is made that the vortex actually originates from the
collision between the flowing current and the boundaries, due to the long
electron mean free path and the consequent ballistic transport caused by the
specific linear spectrum of graphene.
| arxiv topic:cond-mat.mes-hall |
arxiv_dataset-111961905.01164 | SinGAN: Learning a Generative Model from a Single Natural Image
cs.CV
We introduce SinGAN, an unconditional generative model that can be learned
from a single natural image. Our model is trained to capture the internal
distribution of patches within the image, and is then able to generate high
quality, diverse samples that carry the same visual content as the image.
SinGAN contains a pyramid of fully convolutional GANs, each responsible for
learning the patch distribution at a different scale of the image. This allows
generating new samples of arbitrary size and aspect ratio, that have
significant variability, yet maintain both the global structure and the fine
textures of the training image. In contrast to previous single image GAN
schemes, our approach is not limited to texture images, and is not conditional
(i.e. it generates samples from noise). User studies confirm that the generated
samples are commonly confused to be real images. We illustrate the utility of
SinGAN in a wide range of image manipulation tasks.
| arxiv topic:cs.CV |
arxiv_dataset-111971905.01264 | Distinguishing Dirac and Majorana neutrinos by their gravi-majoron
decays
hep-ph
Neutrinos may acquire small Dirac or Majorana masses by new low-energy
physics in terms of the chiral gravitational anomaly, as proposed by Dvali and
Funcke (2016). This model predicts fast neutrino decays, $\nu_i\to\nu_j+\phi$
and $\nu_i\to\bar{\nu}_j+\phi$, where the gravi-majorons $\phi$ are
pseudoscalar Nambu-Goldstone bosons. The final-state neutrino and antineutrino
distributions differ depending on the Dirac or Majorana mass of the initial
state. This opens a channel for distinguishing these cases, for example in the
spectrum of high-energy astrophysical neutrinos. In particular, we put bounds
on the neutrino lifetimes in the Majorana case, ${\tau_2}/{m_2}> 1.1\times
10^{-3}(6.7\times 10^{-4})~{\rm s/eV}$ and ${\tau_3}/{m_3}> 2.2\times
10^{-5}(1.3\times 10^{-4})~{\rm s/eV}$ at 90% CL for hierarchical (degenerate)
masses, using data from experiments searching for antineutrino appearance from
the Sun.
| arxiv topic:hep-ph |
arxiv_dataset-111981905.01364 | The bimodal [Mg/Fe] versus [Fe/H] bulge sequence as revealed by APOGEE
DR14
astro-ph.GA
The Galactic bulge has a bimodal metallicity distribution function: different
kinematic, spatial, and, potentially, age distributions characterize the
metal-poor and metal-rich components. Despite this observed dichotomy, which
argues for different formation channels for those stars, the distribution of
bulge stars in the $\alpha$-abundance versus metallicity plane has been found
so far to be a rather smooth single sequence. We use data from the fourteenth
data release of the APOGEE spectroscopic survey (DR14) to investigate the
distribution in the Mg abundance (as tracer of the
$\alpha$-elements)-versus-metallicity plane of a sample of stars selected to be
in the inner region of the bulge. A clean sample has been selected from the
DR14 using a set of data- and pipeline-flags to ensure the quality of their
fundamental parameters and elemental abundances. An additional selection made
use of computed spectro-photometric distances to select a sample of likely
bulge stars as those with ${\rm R_{GC}\leq 3.5~kpc}$. We adopt magnesium
abundance as an $\alpha$-abundance proxy for our clean sample as it has been
proven to be the most accurate $\alpha$-element as determined by ASPCAP, the
pipeline for data products from APOGEE spectra. From the distribution of our
bulge sample in the [Mg/Fe]-versus-[Fe/H] plane, we found that the sequence is
bimodal. This bimodality is given by the presence of a low-Mg sequence of stars
parallel to the main high-Mg sequence over a range of $\sim 0.5$~dex around
solar metallicity. The two sequences merge above ${\rm [Fe/H]\sim0.15~ dex}$
into a single sequence whose dispersion in [Mg/Fe] is larger than either of the
two sequences visible at lower metallicity. This result is confirmed when we
consider stars in our sample that are inside the bulge region according to
trustworthy Gaia DR2 distances.
| arxiv topic:astro-ph.GA |
arxiv_dataset-111991905.01464 | The search for empirical formulae for the aftershocks descriptions of a
strong earthquake
physics.geo-ph
The paper is based on the report read by the author on October 24, 2018 at
the meeting of the Scientific Council of the Institute of Earth Physics of the
Russian Academy of Sciences. The report was dedicated to the 150th anniversary
of the outstanding Japanese seismologist Fusakichi Omori. As is known, Omori
established the first empirical law of the earthquakes physics, bearing his
name. The Omori law states that the frequency of aftershocks on average
decreases hyperbolically over the time. Three versions of Omori law are
described briefly. The recent version allows to poses the inverse problem of
the earthquake source, that cools down after the main shock.
Keywords: earthquake source, aftershocks equation, deactivation coefficient,
inverse problem
| arxiv topic:physics.geo-ph |
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