title:
The topological type of spaces consisting of certain metrics on locally
  compact metrizable spaces with the compact-open topology

abstract:
  For a separable locally compact but not compact metrizable space $X$, let
$\alpha X = X \cup \{x_\infty\}$ be the one-point compactification with the
point at infinity $x_\infty$. We denote by $EM(X)$ the space consisting of
admissible metrics on $X$, which can be extended to an admissible metric on
$\alpha X$, endowed with the compact-open topology. Let $ \mathbf{c}_0 \subset
(0,1)^\mathbb{N}$ be the space of sequences converging to $0$. In this paper,
we shall show that if $X$ is separable, locally connected and locally compact
but not compact, and there exists a sequence $\{C_i\}$ of connected sets in $X$
such that for all positive integers $i, j \in \mathbb{N}$ with $|i - j| \leq
1$, $C_i \cap C_j \neq \emptyset$, and for each compact set $K \subset X$,
there is a positive integer $i(K) \in \mathbb{N}$ such that for any $i \geq
i(K)$, $C_i \subset X \setminus K$, then $EM(X)$ is homeomorphic to $
\mathbf{c}_0$.


title:
A numerical criterion evaluating the robustness of planetary
  architectures; applications to the $\upsilon$ Andromed{\ae} system

abstract:
  We revisit the problem of the existence of KAM tori in extrasolar planetary
systems. Specifically, we consider the $\upsilon$ Andromed{\ae} system, by
modelling it with a three-body problem. This preliminary study allows us to
introduce a natural way to evaluate the robustness of the planetary orbits,
which can be very easily implemented in numerical explorations. We apply our
criterion to the problem of the choice of a suitable orbital configuration
which exhibits strong stability properties and is compatible with the
observational data that are available for the $\upsilon$ Andromed{\ae} system
itself.


title: Bigraded notions of formality and Aeppli-Bott-Chern-Massey products

abstract:
  We introduce and study notions of bigraded formality for the algebra of forms
on a complex manifold, along with their relation to higher
Aeppli-Bott-Chern-Massey products which extend the case of triple products
studied by Angella-Tomassini. We show that these Aeppli-Bott-Chern-Massey
products on complex manifolds pull back non-trivially to the blow-up along a
complex submanifold, as long their degree is less than the real codimension of
the submanifold.


title:
Accessing negative Poisson`s ratio of graphene by machine learning
  interatomic potentials

abstract:
  The negative Poisson`s ratio (NPR) is a novel property of materials, which
enhances the mechanical feature and creates a wide range of application
prospects in lots of fields, such as aerospace, electronics, medicine, etc.
Fundamental understanding on the mechanism underlying NPR plays an important
role in designing advanced mechanical functional materials. However, with
different methods used, the origin of NPR is found different and conflicting
with each other, for instance, in the representative graphene. In this study,
based on machine learning technique, we constructed a moment tensor potential
(MTP) for molecular dynamics (MD) simulations of graphene. By analyzing the
evolution of key geometries, the increase of bond angle is found to be
responsible for the NPR of graphene instead of bond length. The results on the
origin of NPR are well consistent with the start-of-art first-principles, which
amend the results from MD simulations using classic empirical potentials. Our
study facilitates the understanding on the origin of NPR of graphene and paves
the way to improve the accuracy of MD simulations being comparable to
first-principle calculations. Our study would also promote the applications of
machine learning interatomic potentials in multiscale simulations of functional
materials. *Author


title:
Alexa versus Alexa: Controlling Smart Speakers by Self-Issuing Voice
  Commands

abstract:
  We present Alexa versus Alexa (AvA), a novel attack that leverages audio
files containing voice commands and audio reproduction methods in an offensive
fashion, to gain control of Amazon Echo devices for a prolonged amount of time.
AvA leverages the fact that Alexa running on an Echo device correctly
interprets voice commands originated from audio files even when they are played
by the device itself -- i.e., it leverages a command self-issue vulnerability.
Hence, AvA removes the necessity of having a rogue speaker in proximity of the
victim's Echo, a constraint that many attacks share. With AvA, an attacker can
self-issue any permissible command to Echo, controlling it on behalf of the
legitimate user. We have verified that, via AvA, attackers can control smart
appliances within the household, buy unwanted items, tamper linked calendars
and eavesdrop on the user. We also discovered two additional Echo
vulnerabilities, which we call Full Volume and Break Tag Chain. The Full Volume
increases the self-issue command recognition rate, by doubling it on average,
hence allowing attackers to perform additional self-issue commands. Break Tag
Chain increases the time a skill can run without user interaction, from eight
seconds to more than one hour, hence enabling attackers to setup realistic
social engineering scenarios. By exploiting these vulnerabilities, the
adversary can self-issue commands that are correctly executed 99% of the times
and can keep control of the device for a prolonged amount of time. We reported
these vulnerabilities to Amazon via their vulnerability research program, who
rated them with a Medium severity score. Finally, to assess limitations of AvA
on a larger scale, we provide the results of a survey performed on a study
group of 18 users, and we show that most of the limitations against AvA are
hardly used in practice.


title: Kirin: A Quadruped Robot with High Payload Carrying Capability

abstract:
  The quadruped robot is a versatile mobile platform with potential ability for
high payload carrying. However, most of the existing quadruped robots aim at
high maneuverability, highly dynamic and agile locomotion. In spite of this,
payload carrying is still an indispensable ability for the quadruped robots.
Design of a quadruped robot with high payload capacity is yet deeply explored.
In this study, a 50 kg electrically-actuated quadruped robot, Kirin, is
presented to leverage the payload carrying capability. Kirin is an
characterized with prismatic quasi-direct-drive (QDD) leg. This mechanism
greatly augments the payload carrying capability. This study presents several
design principles for the payload-carrying-oriented quadruped robots, including
the mechanical design, actuator parameters selection, and locomotion control
method. The theoretical analysis implies that the lifting task tends to be a
bottleneck for the existing robots with the articulated knee joints. By using
prismatic QDD leg, the payload carrying capability of Kirin is enhanced
greatly. To demonstrate Kirin's payload carrying capability, in preliminary
experiment, up to 125 kg payload lifting in static stance and 50 kg payload
carrying in dynamic trotting are tested. Whole body compliance with payload
carrying is also demonstrated.


title:
Sulphur-rich cold gas around the hot core precursor G328.2551-0.5321. An
  APEX unbiased spectral survey of the 2 mm, 1.2 mm, and 0.8 mm atmospheric
  windows

abstract:
  During star formation, the dense gas undergoes significant chemical evolution
leading to the emergence of a rich variety of molecules associated with hot
cores and hot corinos. The physical and chemical conditions are poorly
constrained; the early phases of emerging hot cores in particular represent an
unexplored territory. We provide here a full molecular inventory of a massive
protostellar core that is proposed to be a precursor of a hot core. We
performed an unbiased spectral survey towards the hot core precursor associated
with clump G328.2551-0.5321 between 159GHz and 374GHz. To identify the spectral
lines, we used rotational diagrams and radiative transfer modelling assuming
LTE. We detected 39 species and 26 isotopologues, and were able to distinguish
a warm and compact inner region, a colder more extended envelope, and the
kinematic signatures of the accretion shocks that have previously been observed
with ALMA. We associate most of the emission of the small molecules with the
cold gas, while the molecular emission of the warm gas is enriched by complex
organic molecules (COMs). We find a high abundance of S-bearing molecules in
the cold gas phase suggesting a low sulphur depletion, with a factor of > 1%.
We identify nine COMs in the warm gas, four in the cold gas, and four towards
the accretion shocks. The high abundances of S-bearing species originating from
the undisturbed gas may suggest a contribution from shocked gas at the outflow
cavity walls. The molecular composition of the warm gas is similar to that of
both hot cores and hot corinos, but the molecular abundances are closer to the
values found towards hot corinos than to values found towards hot cores.
Considering the compactness of the warm region and its moderate temperature, we
suggest that thermal desorption has not been completed towards this object yet,
representing an early phase of the emergence of hot cores.


title:
Proton charge radius from a dispersive analysis of the latest space-like
  $e$-$p$ scattering data

abstract:
  We present a dispersion theoretical analysis of recent date from
electron-proton scattering. This allows for a high-precision extraction of the
electric and magnetic radius of the proton, $r_E = (0.839\pm
0.002{}^{+0.002}_{-0.003})$~fm and $r_M = (0.846\pm
0.001{}^{+0.001}_{-0.005})$~fm, where the first error refers to the statistical
type estimated from the bootstrap method, and the second one refers to the
systematic uncertainty related to the underlying spectral functions.


title:
Emergent conformational properties of end-tailored transversely
  propelling polymers

abstract:
  We study the dynamics and conformations of a single active semiflexible
polymer whose monomers experience a propulsion force perpendicular to the local
tangent, with the end beads being different from the inner beads
("end-tailored"). Using Langevin simulations, we demonstrate that, apart from
sideways motion, the relative propulsion strength between the end beads and the
polymer backbone significantly changes the conformational properties of the
polymers as a function of bending stiffness, end-tailoring and propulsion
force. Expectedly, for slower ends the polymer curves away from the moving
direction, while faster ends lead to opposite curving, in both cases slightly
reducing the center of mass velocity compared to a straight fiber.
Interestingly, for faster end beads there is a rich and dynamic morphology
diagram: the polymer ends may get folded together to 2D loops or hairpin-like
conformations that rotate due to their asymmetry in shape and periodic flapping
motion around a rather straight state during full propulsion is also possible.
We rationalize the simulations using scaling and kinematic arguments and
present the state diagram of the conformations. Sideways propelled fibers
comprise a rather unexplored and versatile class of self-propellers, and their
study will open novel ways for designing, e.g. motile actuators or mixers in
soft robotics.


title:
Elucidating the Degradation Mechanism of Gd2Zr2O7 Waste Form under
  Multi-Energy He Ion Irradiation

abstract:
  We studied the microstructural and helium bubbling evolutions of Gd2Zr2O7
waste form with immobilized TRPO (50 wt%) under multi-energy He ion
irradiation. Three structurally heterogeneous regions for the Gd2Zr2O7 waste
form were found as a function of the depth from the He-irradiated surface.
Specifically, at a depth less than 40 nm below the He-irradiated surface
(Region I) the Gd2Zr2O7 waste form is completely amorphous with large spherical
He bubbles (5-25 nm). In the intermediate region, Region II, (40-800 nm)
partially amorphized Gd2Zr2O7 waste form accompanied with ribbon-like He
bubbles that may lead to the formation of microcracks is observed. The
crystallinity is not impacted in Region III for a depth of more than 800 nm.
For the first time, we elucidated that the Gd2Zr2O7 waste form, which was
considered to be structurally intact at 100 dpa, is completely amorphized at
6.5 dpa with the synergistic displacement damage, electronic energy loss, and
He concentration enabled. This study leads to new physical insights into
amorphization and He bubbles formation mechanisms of Gd2Zr2O7 waste form under
multi-energy He irradiation, which is essential for the design and optimization
of irradiation-resistant ceramic waste matrices.


title: Revisiting Over-smoothing in BERT from the Perspective of Graph

abstract:
  Recently over-smoothing phenomenon of Transformer-based models is observed in
both vision and language fields. However, no existing work has delved deeper to
further investigate the main cause of this phenomenon. In this work, we make
the attempt to analyze the over-smoothing problem from the perspective of
graph, where such problem was first discovered and explored. Intuitively, the
self-attention matrix can be seen as a normalized adjacent matrix of a
corresponding graph. Based on the above connection, we provide some theoretical
analysis and find that layer normalization plays a key role in the
over-smoothing issue of Transformer-based models. Specifically, if the standard
deviation of layer normalization is sufficiently large, the output of
Transformer stacks will converge to a specific low-rank subspace and result in
over-smoothing. To alleviate the over-smoothing problem, we consider
hierarchical fusion strategies, which combine the representations from
different layers adaptively to make the output more diverse. Extensive
experiment results on various data sets illustrate the effect of our fusion
method.


title:
Proton charge radius from a dispersive analysis of the experimental data
  over the space- and time-like regions

abstract:
  We present a dispersion theoretical analysis of the experimental data on the
electromagnetic form factors of the nucleon covering both the space- and
time-like regions. The nucleon form factors over the full range of momentum
transfers and the nucleon radius are extracted with high precision. The
statistical uncertainties of the extracted form factors and radius are
estimated using the bootstrap method, while systematic errors are determined
from variations of the spectral functions. For the proton charge radius, we
find $r_E^p = 0.840^{+0.003}_{-0.002}{}^{+0.002}_{-0.002}$~fm, in line with
previous analyses of spacelike data alone and also the muonic Lamb shift
determination.


title:
Accelerated iterative tomographic reconstruction with x-ray edge
  illumination

abstract:
  Compared to standard tomographic reconstruction, iterative approaches offer
the possibility to account for extraneous experimental influences, which allows
for a suppression of related artifacts. However, the inclusion of corresponding
parameters in the iterative forward model typically leads to longer computation
times. Here, we demonstrate experimentally for phase sensitive X-ray imaging
based on the edge illumination principle that inadequately sampled illumination
curves result in ring artifacts in tomographic reconstructions. We take
advantage of appropriately sampled illumination curves instead, which enables
us to eliminate the corresponding parameter from the forward model and
substantially increase computational speed. In addition, we demonstrate a 30\%
improvement in spatial resolution of the iterative approach compared with the
standard non-iterative single shot approach. Further, we report on several
significant improvements in our numerical implementation of the iterative
approach, which we make available online with this publication. Finally, we
show that the combination of both experimental and algorithmic advancement lead
to a total speed increase by one order of magnitude and an improved contrast to
noise ratio in the reconstructions.


title:
The cyclic behaviour in the N-S asymmetry of sunspots and solar plages
  for the period 1910 to 1937 using data from Ebro catalogues

abstract:
  The heliophysics catalogues published by the Ebro Observatory during
1910--1937 have been converted into a digital format in order to provide the
data for computational processing. This has allowed us to study in detail the
North-South (N-S) asymmetry of solar activity in that period, focusing on two
different structures located at two different layers of the solar atmosphere:
sunspots (Photosphere) and solar plages (Chromosphere). The examination of the
absolute and normalised N-S asymmetry indices in terms of their monthly sum of
occurrences and areas has made possible to find out a cyclic behaviour in the
solar activity, in which the preferred hemisphere changes systematically with a
global period of 7.9 $\pm$ 0.2 yr. In order to verify and quantify accurately
this periodicity and study its prevalence in time, we employed the
RGO-USAF/NOAA sunspot data series during 1874--2016. Then, we examined each
absolute asymmetry index time series through different techniques as the power
spectrum analysis, the Complete Ensemble Empirical Mode Decomposition With
Adaptive Noise algorithm, or the Morlet wavelet transform. The combined results
reveal a cyclic behaviour at different time scales, consisting in two quite
stable periodicities of 1.47 $\pm$ 0.02 yr and 3.83 $\pm$ 0.06 yr, which
coexist with another three discontinuous components with more marked
time-varying periods with means of 5.4 $\pm$ 0.2 yr, 9.0 $\pm$ 0.2 yr, and 12.7
$\pm$ 0.3 yr. Moreover, during 1910--1937, only two dominant signals with
averaged periods of 4.10 $\pm$ 0.04 yr and 7.57 $\pm$ 0.03 yr can be clearly
observed. Finally, in both signals, periods are slightly longer for plages in
comparison with sunspots.


title:
A rapidly fading star as a type II obscuring intermediate luminosity
  optical transient (ILOT) in a triple star system

abstract:
  We propose a triple-star scenario where the merger of two pre-main sequence
low mass stars, <0.5Mo, ejects a dusty equatorial outflow that obscures and
temporarily cause the disappearance of a massive star, >8 Mo. The merger of the
low-mass inner binary powers a fain outburst, i.e., a faint intermediate
luminosity optical transient (ILOT), but its main effect that can last for
decades is to (almost) disappear the luminous massive star of the triple
system. The typical orbital period of the triple system in about a year. The
merger process proceeds as the more massive star of the two low-mass pre-main
sequence star starts to transfer mass to the least massive star in the triple
system and as a result of that expands. This 'type II obscuring ILOT' scenario
in a triple star system might account for the fading, re-brightening, and then
re-fading of the massive post-main sequence star M101-OC1. Our study
strengthens the claim that there are alternative scenarios to account for the
(almost) disappearing of massive stars, removing the need for failed
supernovae. In these scenarios the disappearing is temporary, months to
decades, and therefore at later time the massive star explodes as a core
collapse supernova even if it forms a black hole.


title: Interfacial activity dynamics of confined active droplets

abstract:
  Oil droplets in aqueous surfactant solution show spontaneous self-propulsion
and dynamics ranging from straight-line to unsteady motion with increasing
P\'eclet number. Recent studies have shown that products of interfacial
activity (oil-filled micelles) can lead to multistable higher-mode flow fields
and chemorepulsive phenomena. To investigate such chemodynamic effects, we have
studied disk-like flattened droplets that are pinned at the top and bottom of
the reservoir and produce only pumping flow. With increasing droplet radius we
observe the following: (i) vortical structures generated by the droplet
migrating around the interface, (ii) bistability between a dipolar and
quadrupolar flow mode, and, eventually, (iii) a transition to multipolar modes.
For a deeper analysis, we measured flow fields by particle image velocimetry
and compared them to a hydrodynamic model based on a Brinkman squirmer. A
simultaneous quantification of the flow fields and oil-filled micelle
distribution suggests that a local buildup of chemical products leads to a
saturation of the surface, which affects the propulsion mechanism. Hence, we
describe the interfacial activity dynamics in time and space.


title:
Population Control Techniques for Time-Dependent and Eigenvalue Monte
  Carlo Neutron Transport Calculations

abstract:
  A comprehensive study on population control technique (PCT) for
time-dependent and eigenvalue Monte Carlo (MC) neutron transport simulations is
presented. We define PCT as a technique that takes a censused population and
returns a controlled, unbiased one. A new perspective based on an abstraction
of particle census and population control is explored, paving the way to
improved understanding and application of the concepts. Five distinct PCTs
identified from the literature are reviewed: Simple Sampling (SS),
Splitting-Roulette (SR), Combing (CO), modified Combing (COX), and
Duplicate-Discard (DD). A theoretical analysis of how much uncertainty is
introduced to a population by each PCT is presented. Parallel algorithms for
the PCTs applicable for both time-dependent and eigenvalue MC simulations are
proposed. The relative performances of the PCTs based on runtime and tally mean
error or standard deviation are assessed by solving time-dependent and
eigenvalue test problems. It is found that SR and CO are equally the most
performant techniques, closely followed by DD.


title:
Exact solutions for charged spheres and their stability. II. Anisotropic
  Fluids

abstract:
  We study exact solutions of the Einstein-Maxwell equations for the interior
gravitational field of static spherically symmetric charged compact spheres.
The spheres consist of an anisotropic fluid with a charge distribution that
gives rise to a static radial electric field. The density of the fluid has the
form $\rho (r) = \rho_o + \alpha r^2$ (here $\rho_o$ and $\alpha$ are
constants) and the total charge $q(r)$ within a sphere of radius $r$ has the
form $q = \beta r^3$ (with $\beta$ a constant). We evaluate the critical values
of $M/R$ for these spheres as a function of $Q/R$ and compare these values with
those given by the Andr\'{e}asson formula.


title:
A novel HD Computing Algebra: Non-associative superposition of states
  creating sparse bundles representing order information

abstract:
  Information inflow into a computational system is by a sequence of
information items. Cognitive computing, i.e. performing transformations along
that sequence, requires to represent item information as well as sequential
information. Among the most elementary operations is bundling, i.e. adding
items, leading to 'memory states', i.e. bundles, from which information can be
retrieved. If the bundling operation used is associative, e.g. ordinary
vector-addition, sequential information can not be represented without imposing
additional algebraic structure. A simple stochastic binary bundling rule
inspired by the stochastic summation of neuronal activities allows the
resulting memory state to represent both, item information as well as
sequential information as long as it is non-associative. The memory state
resulting from bundling together an arbitrary number of items is
non-homogeneous and has a degree of sparseness, which is controlled by the
activation threshold in summation. The bundling operation proposed allows to
build a filter in the temporal as well as in the items' domain, which can be
used to navigate the continuous inflow of information.


title: Variational problems concerning sub-Finsler metrics in Carnot groups

abstract:
  This paper is devoted to the study of geodesic distances defined on a
subdomain of a given Carnot group, which are bounded both from above and from
below by fixed multiples of the Carnot-Carath\'{e}odory distance. We show that
the uniform convergence (on compact sets) of these distances can be
equivalently characterized in terms of $\Gamma$-convergence of several kinds of
variational problems. Moreover, we investigate the relation between the class
of intrinsic distances, their metric derivatives and the sub-Finsler convex
metrics defined on the horizontal bundle.


title:
Leading twist GTMDs at nonzero skewness and Wigner distributions in
  boost-invariant longitudinal position space

abstract:
  We investigate the leading twist quark generalized transverse momentum
distributions (GTMDs) at nonzero skewness in a light-front quark-diquark model
for the nucleon motivated by soft-wall AdS/QCD. The boost-invariant
longitudinal coordinate, $\sigma=\frac{1}{2} b^- P^+$, is identified as the
Fourier conjugate of the skewness. The Fourier transform of the GTMDs with
respect to the skewness variable $\xi$ can be employed to provide the Wigner
distributions in the boost-invariant longitudinal position space $\sigma$, the
coordinate conjugate to light-front time, $\tau=t+z/c$. The Wigner
distributions in the longitudinal position space exhibit diffraction patterns,
which are analogous to the diffractive scattering of a wave in optics.


title:
Parabolic Anderson model on critical Galton-Watson trees in a Pareto
  environment

abstract:
  The parabolic Anderson model is the heat equation with some extra spatial
randomness. In this paper we consider the parabolic Anderson model with i.i.d.
Pareto potential on a critical Galton-Watson tree conditioned to survive. We
prove that the solution at time $t$ is concentrated at a single site with high
probability and at two sites almost surely as $t \to \infty$. Moreover, we
identify asymptotics for the localisation sites and the total mass, and show
that the solution $u(t,v)$ at a vertex $v$ can be well-approximated by a
certain functional of $v$. The main difference with earlier results on
$\mathbb{Z}^d$ is that we have to incorporate the effect of variable vertex
degrees within the tree, and make the role of the degrees precise.


title:
Direct observational evidence of an oceanic dual kinetic energy cascade
  and its seasonality

abstract:
  The Ocean's turbulent energy cycle has a paradox; large-scale eddies under
the control of Earth's rotation primarily transfer kinetic energy (KE) to
larger scales via an inverse cascade, while a transfer to smaller scales is
needed to accomplish dissipation. It has been argued, using numerical
simulations, that fronts, waves and other turbulent structures can produce a
forward cascade of KE toward dissipation scales. However, this forward cascade
and its coexistence with known inverse cascade were not confirmed in
observations. Here we present the first evidence of a dual KE cascade in the
Ocean by analyzing velocity measurements from surface drifters released in the
Gulf of Mexico. Our results show that KE is injected at two dominant scales and
transferred to both large and small scales, with the downscale flux dominating
at scales smaller than ~1-10km. The cascade rates are modulated seasonally,
with stronger KE injection and forward transfer during winter.

categories: physics.ao-ph nlin.CD physics.data-an physics.flu-dyn


title: Non-Hermitian quantum many-body scar

abstract:
  Ergodicity depicts a thorough exploration of phase space to reach thermal
equilibrium for most isolated many-body systems. Recently, the discovery of
persistent revivals in the Rydberg-atom quantum simulator has revealed a weakly
ergodicity breaking mechanism dubbed as quantum many-body scars, which are a
set of nonthermal states storing the initial quantum information through
long-time dynamics in the otherwise thermal spectrum. However, until now, the
quantum scars have only been studied in closed systems with Hermiticity. Here,
we establish the non-Hermitian quantum many-body scars in open systems and
characterize their nature from the entanglement entropy, the physical
observable and the energy level statistics. Notably, these signatures of the
non-Hermitian scarred states switch from the real-energy axis to the
imaginary-energy axis after a real-to-complex spectra transition, where an
exceptional point and a quantum tricritical point emerge simultaneously. We
further examine their stability against external fields and establish the whole
phase diagram. In the real-spectrum region, we reveal that the non-Hermitian
scars are more fragile than Hermitian counterparts when increasing the strength
of non-Hermiticity. Our results may offer insights on ergodicity-breaking and
clues for realizing long-lived coherent states in open quantum many-body
systems.


title:
Augmentation of Generalized Multivariable Grid-Forming Control for Power
  Converters with Cascaded Controllers

abstract:
  The classic design of grid-forming control strategies for power converters
rely on the stringent assumption of the timescale separation between DC and AC
states and their corresponding control loops, e.g., AC and DC loops, power and
cascaded voltage and current loops, etc. This paper proposes a multi-input
multi-output based grid-forming (MIMO-GFM) control for the power converters
using a multivariable feedback structure. First, the MIMO-GFM control couples
the AC and DC loops by a general multivariable control transfer matrix. Then,
the parameters design is transformed into a standard fixed-structure H-infinity
synthesis. By this way, all the loops can be tuned simultaneously and optimally
without relying on the assumptions of loop decoupling. Therefore, a superior
and robust performance can be achieved. Experimental results verify the
proposed method.


title: Generalized Inverse Based Decoding

abstract:
  The concept of Generalized Inverse based Decoding (GID) is introduced, as an
algebraic framework for the syndrome decoding problem (SDP) and low weight
codeword problem (LWP). The framework has ground on two characterizations by
generalized inverses (GIs), one for the null space of a matrix and the other
for the solution space of a system of linear equations over a finite field.
Generic GID solvers are proposed for SDP and LWP. It is shown that information
set decoding (ISD) algorithms, such as Prange, Lee-Brickell, Leon, and Stern's
algorithms, are particular cases of GID solvers. All of them search GIs or
elements of the null space under various specific strategies. However, as the
paper shows the ISD variants do not search through the entire space, while our
solvers do even when they use just one Gaussian elimination. Apart from these,
our GID framework clearly shows how each ISD algorithm, except for Prange's
solution, can be used as an SDP or LWP solver. A tight reduction from our
problems, viewed as optimization problems, to the MIN-SAT problem is also
provided. Experimental results show a very good behavior of the GID solvers.
The domain of easy weights can be reached by a very few iterations and even
enlarged.


title: Entropy Bounds for Embedded Self-shrinkers with Rotational Symmetry

abstract:
  In this work, we study the space of complete embedded rotationally symmetric
self-shrinking hypersurfaces in $\mathbb{R}^{n+1}$. First, we derive explicit
upper bounds for the entropy of all such self-shrinkers. Second, as an
application we prove a smooth compactness theorem on the space of all such
shrinkers. We also prove that there are only finitely many such self-shrinkers
with an extra reflection symmetry.


title:
Parametric geometry of numbers over a number field and extension of
  scalars

abstract:
  Schmidt and Summerer parametric geometry of numbers deals with rational
approximation to points in $\mathbb{R}^n$. We extend this theory to a number
field $K$ and its completion $K_w$ at a place $w$ in order to treat
approximation over $K$ to points in $K_w^n$. As a consequence, we find that
exponents of approximation over $\mathbb{Q}$ in $\mathbb{R}^n$ have the same
spectrum as their generalizations over $K$ in $K_w^n$. When $w$ has relative
degree one over a place $\ell$ of $\mathbb{Q}$, we further relate approximation
over $K$ to a point $\boldsymbol{\xi}$ in $K_w^n$, to approximation over
$\mathbb{Q}$ to a point $\Xi$ in $\mathbb{Q}_\ell^{nd}$, obtained by extension
of scalars, where $d$ is the degree of $K$ over $\mathbb{Q}$. By combination
with a result of Bel, this allows us to construct algebraic curves in
$\mathbb{R}^{3d}$ defined over $\mathbb{Q}$, of degree $2d$, containing points
that are very singular with respect to rational approximation.


title: Tutorial: Topology, waves, and the refractive index

abstract:
  This tutorial is divided into two parts: the first examines the application
of topology to problems in wave physics. The origins of the Chern number are
reviewed, where it is shown that this counts the number of critical points of a
complex tangent vector field on the surface. We then show that this quantity
arises naturally when calculating the dispersion of modes in any linear system,
and give examples of its application to find one--way propagating interface
modes in both continuous and periodic materials.
  The second part offers a physical interpretation for the Chern number, based
on the idea that the critical points which it records can be understood as
points where the refractive index vanishes. Using the theory of crystal optics,
we show that when the refractive index vanishes in a complex valued direction,
the wave is forced to circulate in only one sense, and this is the origin of
the one-way propagation of topological interface states. We conclude by
demonstrating that this idea of `zero refractive index in a complex direction'
can be used as a shortcut to find acoustic and electromagnetic materials
supporting one-way interface states.

categories: physics.optics cond-mat.mtrl-sci math-ph math.MP


title: Constructing non-semisimple modular categories with local modules

abstract:
  We define the class of rigid Frobenius algebras in a (non-semisimple) modular
category and prove that their categories of local modules are, again, modular.
This generalizes previous work of A. Kirillov, Jr. and V. Ostrik [Adv. Math.
171 (2002), no. 2] in the semisimple setup. Examples of non-semisimple modular
categories via local modules, as well as connections to the authors' prior work
on relative monoidal centers, are provided. In particular, we classify rigid
Frobenius algebras in Drinfeld centers of module categories over group
algebras, thus generalizing the classification by A. Davydov [J. Algebra 323
(2010), no. 5] to arbitrary characteristic.


title:
Polynomial tau-functions of the symplectic KP, orthogonal KP and BUC
  hierarchies

abstract:
  This paper is concerned with the construction of the polynomial tau-functions
of the symplectic KP (SKP), orthogonal KP (OKP) hierarchies and universal
character hierarchy of B-type (BUC hierarchy), which are proved as zero modes
of certain combinations of the generating functions. By applying the strategy
of carrying out the action of the quantum fields on vacuum vector, the
generating functions for symplectic Schur function, orthogonal Schur function
and generalized Q-function have been presented. The remarkable feature is that
polynomial tau-functions are the coefficients of certain family of generating
functions. Furthermore, in terms of the Vandermonde-like identity and
properties of Pfaffian, it is showed that the polynomial tau-functions of the
SKP, OKP and BUC hierarchies canbe written as determinant and Pfaffian forms,
respectively. In addition, the soliton solutions of the SKP and OKP hierarchies
have been discussed.


title: On-Time Communications Over Fading Channels

abstract:
  We consider the on-time transmissions of a sequence of packets over a fading
channel.Different from traditional in-time communications, we investigate how
many packets can be received $\delta$-on-time, meaning that the packet is
received with a deviation no larger than $\delta$ slots. In this framework, we
first derive the on-time reception rate of the random transmissions over the
fading channel when no controlling is used. To improve the on-time reception
rate, we further propose to schedule the transmissions by delaying, dropping,
or repeating the packets. Specifically, we model the scheduling over the fading
channel as a Markov decision process (MDP) and then obtain the optimal
scheduling policy using an efficient iterative algorithm. For a given sequence
of packet transmissions, we analyze the on-time reception rate for the random
transmissions and the optimal scheduling. Our analytical and simulation results
show that the on-time reception rate of random transmissions decreases (to
zero) with the sequence length.By using the optimal packet scheduling, the
on-time reception rate converges to a much larger constant. Moreover, we show
that the on-time reception rate increases if the target reception interval
and/or the deviation tolerance $\delta$ is increased, or the randomness of the
fading channel is reduced.


title: Semantically Proportional Patchmix for Few-Shot Learning

abstract:
  Few-shot learning aims to classify unseen classes with only a limited number
of labeled data. Recent works have demonstrated that training models with a
simple transfer learning strategy can achieve competitive results in few-shot
classification. Although excelling at distinguishing training data, these
models are not well generalized to unseen data, probably due to insufficient
feature representations on evaluation. To tackle this issue, we propose
Semantically Proportional Patchmix (SePPMix), in which patches are cut and
pasted among training images and the ground truth labels are mixed
proportionally to the semantic information of the patches. In this way, we can
improve the generalization ability of the model by regional dropout effect
without introducing severe label noise. To learn more robust representations of
data, we further take rotate transformation on the mixed images and predict
rotations as a rule-based regularizer. Extensive experiments on prevalent
few-shot benchmarks have shown the effectiveness of our proposed method.


title:
Bode-based speed Proportional Integral and notch filter tuning of a
  Permanent Magnet Synchronous Machine driven flexible system

abstract:
  A resonance and an antiresonance peak characterize many industrial mechanisms
dynamics driven by a Permanent Magnet Synchronous Motor (PMSM). The presence of
the resonance peak can lead to vibrations and instability of the system. On
that account, advanced methods exist to tune the speed Proportional Integral
(PI) controller based on adaptive or fuzzy theory. However, those methods
require expertise in control theory and are not available in commercial drives.
For that, this paper proposes a Bode-based method for PI parameters selection
in combination with a notch filter that can be easily set in any industrial
drive. The proposed method is compared with conventional tuning methods in a
physical setup.


title:
Information and communication technology initiatives for knowledge
  sharing in agriculture

abstract:
  A survey on status and trends of information and communication technologies
(ICT) use for knowledge sharing in agriculture was attempted. Among asian
countries, India comes under the second next category after the advanced user
category comprising Japan, South Korea and Taiwan. Both profit-motive and
business augmentation on one hand and community services and rural welfare on
the other have been the objectives of ICT-based models in agriculture in India.
The ICT endeavours for agriculture belong to a wide array of agencies, viz
private sector, public sector, self-help groups and NGOs, and also include
combined endeavours. e-Learning is being increasingly resorted to both in (i)
in campus or 'presence' mode, and (ii) 'distance' mode. Its use is gradually
easing-out the stakeholders from the stranglehold of the inter-deterrence of
the 3 arms of the 'Iron Triangle', viz (i) quality, (ii) access, and (iii)
cost. The social groups having less mobility are poised to benefit more from
this mode of education. This could also be one of the potent tools to bring
about gender mainstreaming. e-Learning is being integrated into the existing
organizational and educational structure as a hybrid system that can be called
'ICT-supported learning'. Connectivity, content development, infrastructure
development, faculty developmeat, need assessment on a continuum, linking the
node3 and formation of consortia etc. are the areas identified that need to be
supported and developed.


title: Shaping entangled photons through emulated turbulent atmosphere

abstract:
  Scattering by atmospheric turbulence is one of the main challenges in
creating long free-space optical links, and specifically links of entangled
photons. Classical compensation methods are hard to apply to entangled photons,
due to inherently low signal to noise ratios and the fragility of entanglement.
We have recently shown that we can use the bright laser beam that pumps
spontaneous parametric down conversion to control the spatial correlations
between entangled photons for compensating their scattering. In this work, we
apply the pump-shaping technique to compensate for scrambling of correlations
between entangled photons that scatter by emulated atmospheric turbulence. We
use a spatial light modulator and Kolmogorov's turbulence model to emulate
atmospheric turbulence in the lab, and enhance the entangled photons' signal by
a factor of fifteen using pump optimization. We show this for both static and
dynamic emulated atmosphere, and demonstrate also the compensation of the
scattering of a higher-order mode. Our results can open the door towards
realizing free-space quantum links with entangled photons, used in applications
such as quantum key distribution.


title: Strong CO Absorption Features in Massive ETGs

abstract:
  Massive Early-Type Galaxies (ETG) in the local Universe are believed to be
the most mature stage of galaxy evolution. Their stellar population content
reveals the evolutionary history of these galaxies. However, while
state-of-the-art Stellar Population Synthesis (SPS) models provide an accurate
description of observed galaxy spectra in the optical range, the modelling in
the Near-Infrared (NIR) is still in its infancy. Here we focus on NIR CO
absorption features to show, in a systematic and comprehensive manner, that for
massive ETGs, all CO indices, from H through to K band, are significantly
stronger than currently predicted by SPS models. We explore and discuss several
possible explanations of this "CO mismatch", including the effect of
intermediate-age, AGB-dominated, stellar populations, high metallicity
populations, non-solar abundance ratios and the initial mass function. While
none of these effects is able to reconcile models and observations, we show
that ad-hoc "empirical" corrections, taking into account the effect of
CO-strong giant stars in the low-temperature regime, provide model predictions
that are closer to the observations. Our analysis points to the effect of
carbon abundance as the most likely explanation of NIR CO line-strengths,
indicating possible routes for improving the SPS models in the NIR.


title: Critical metrics of the volume functional with pinched curvature

abstract:
  In this paper, we prove that a critical metric of the volume functional with
pinched Weyl curvature is isometric to a geodesic ball in $\mathbb{S}^{n}.$
Moreover, we provide a necessary and sufficient condition on the norm of the
gradient of the potential function in order to classify such critical metrics.


title:
Convex monotone semigroups and their generators with respect to
  $\Gamma$-convergence

abstract:
  We study semigroups of convex monotone operators on spaces of continuous
functions and their behaviour with respect to $\Gamma$-convergence. In contrast
to the linear theory, the domain of the generator is, in general, not invariant
under the semigroup. To overcome this issue, we consider different versions of
invariant Lipschitz sets which turn out to be suitable domains for weaker
notions of the generator. The so-called $\Gamma$-generator is defined as the
time derivative with respect to $\Gamma$-convergence in the space of upper
semicontinuous functions. Under suitable assumptions, we show that the
$\Gamma$-generator uniquely characterizes the semigroup and is determined by
its evaluation at smooth functions. Furthermore, we provide Chernoff
approximation results for convex monotone semigroups and show that
approximation schemes based on the same infinitesimal behaviour lead to the
same semigroup. Our results are applied to semigroups related to stochastic
optimal control problems in finite and infinite-dimensional settings as well as
Wasserstein perturbations of transition semigroups.


title:
Effects of triaxiality and pairing interaction on fission barriers of
  actinide nuclei studied by density-dependence relativistic mean-field theory

abstract:
  We employ density-dependent relativistic mean-field theory to study how the
triaxiality and pairing interaction affect the inner fission barriers of
actinide nuclei. It was found that triaxiality reduced the inner fission
barriers and improved agreement with experimental values for many actinides.
However, about 1-2 MeV discrepancy to the experimental values still remained
for some of the considered nuclei. Such a discrepancy could be made further
smaller by increasing the BCS pairing strength parameter. In this work, we
demonstrated that adjusting the paring strength was effective to reproduce the
experimental inner fission barriers as well as "pairing rotational energy" and
binding energy in a consistent manner for nuclei where the effect of the
triaxiality on the inner fission barriers was significant.


title:
Theory-agnostic Reconstruction of Potential and Couplings from
  Quasi-Normal Modes

abstract:
  In this work, we use a parametrized theory-agnostic approach that connects
the observation of black hole quasi-normal modes with the underlying
perturbation equations, with the goal of reconstructing the potential and the
coupling functions appearing in the latter. The fundamental quasi-normal mode
frequency and its first two overtones are modeled through a second order
expansion in the deviations from general relativity, which are assumed to be
small but otherwise generic. By using a principal component analysis, we
demonstrate that percent-level measurements of the fundamental mode and its
overtones can be used to constrain the effective potential of tensor
perturbations and the coupling functions between tensor modes and ones of
different helicity, without assuming an underlying theory. We also apply our
theory-agnostic reconstruction framework to analyze simulated quasi-normal mode
data produced within specific theories extending general relativity, such as
Chern-Simons gravity.


title: Robust Sparse Voting

abstract:
  Many modern Internet applications, like content moderation and recommendation
on social media, require reviewing and score a large number of alternatives. In
such a context, the voting can only be sparse, as the number of alternatives is
too large for any individual to review a significant fraction of all of them.
Moreover, in critical applications, malicious players might seek to hack the
voting process by entering dishonest reviews or creating fake accounts.
Classical voting methods are unfit for this task, as they usually (a) require
each reviewer to assess all available alternatives and (b) can be easily
manipulated by malicious players.
  This paper defines precisely the problem of robust sparse voting, highlights
its underlying technical challenges, and presents Mehestan, a novel voting
mechanism that solves the problem. Namely, we prove that by using Mehestan, no
(malicious) voter can have more than a small parametrizable effect on each
alternative's score, and we identify conditions of voters comparability under
which any unanimous preferences can be recovered, even when these preferences
are expressed by voters on very different scales.


title: Bilimits in categories of partial maps

abstract:
  The closure of chains of embedding-projection pairs (ep-pairs) under bilimits
in some categories of predomains and domains is standard and well-known. For
instance, Scott's $D_\infty$ construction is well-known to produce directed
bilimits of ep-pairs in the category of directed-complete partial orders, and
de Jong and Escard\'o have formalized this result in the constructive domain
theory of a topos. The explicit construcition of bilimits for categories of
predomains and partial maps is considerably murkier as far as constructivity is
concerned; most expositions employ the constructive taboo that every
lift-algebra is free, reducing the problem to the construction of bilimits in a
category of pointed domains and strict maps. An explicit construction of the
bilimit is proposed in the dissertation of Claire Jones, but no proof is given
so it remained unclear if the category of dcpos and partial maps was closed
under directed bilimits of ep-pairs in a topos. We provide a
(Grothendieck)-topos-valid proof that the category of dcpos and partial maps
between them is closed under bilimits; then we describe some applications
toward models of axiomatic and synthetic domain theory.


title:
The merged-staircase property: a necessary and nearly sufficient
  condition for SGD learning of sparse functions on two-layer neural networks

abstract:
  It is currently known how to characterize functions that neural networks can
learn with SGD for two extremal parameterizations: neural networks in the
linear regime, and neural networks with no structural constraints. However, for
the main parametrization of interest (non-linear but regular networks) no tight
characterization has yet been achieved, despite significant developments.
  We take a step in this direction by considering depth-2 neural networks
trained by SGD in the mean-field regime. We consider functions on binary inputs
that depend on a latent low-dimensional subspace (i.e., small number of
coordinates). This regime is of interest since it is poorly understood how
neural networks routinely tackle high-dimensional datasets and adapt to latent
low-dimensional structure without suffering from the curse of dimensionality.
Accordingly, we study SGD-learnability with $O(d)$ sample complexity in a large
ambient dimension $d$.
  Our main results characterize a hierarchical property, the "merged-staircase
property", that is both necessary and nearly sufficient for learning in this
setting.
  We further show that non-linear training is necessary: for this class of
functions, linear methods on any feature map (e.g., the NTK) are not capable of
learning efficiently. The key tools are a new "dimension-free" dynamics
approximation result that applies to functions defined on a latent space of
low-dimension, a proof of global convergence based on polynomial identity
testing, and an improvement of lower bounds against linear methods for
non-almost orthogonal functions.


title: Hanle rotation signatures in Sr I 4607 {\AA}

abstract:
  Observations of scattering polarization and the Hanle effect in various
spectral lines are increasingly used to complement traditional solar magnetic
field determination techniques. One of the strongest scattering polarization
signals in the photosphere is measured in the Sr I line at 4607.3 {\AA} when
observed close to the solar limb. Here, we present the first observational
evidence of Hanle rotation in the linearly polarized spectrum of this at
several limb distances. We observed with the Zurich IMaging POLarimeter,
ZIMPOL, at the IRSOL observatory, with exceptionally good seeing conditions,
allowing for long integration times. We combined the fast modulating
polarimeter with a slow modulator installed in front of the telescope. This
combination allows the measurement of spectropolarimetric data being highly
precise and unprecedentedly accurate. Fixing the reference direction for
positive Stokes $Q$ parallel to the limb, we detect singly-peaked $U/I$ signals
well above the noise level. We can exclude instrumental origin for such $U/I$
signals. These signatures are exclusively found in the Sr I line, but not in
the adjoining Fe I line, therefore eliminating the Zeeman effect as the
mechanism responsible for their appearance. However, we find a clear spatial
correlation between the circular polarization produced by the Zeeman effect and
the $U/I$ amplitudes. This suggests that the detected $U/I$ signals are the
signatures of Hanle rotation caused by a spatially resolved magnetic field. A
novel measurement technique allows for determining the absolute level of
polarization with unprecedented precision. Using this technique, high-precision
spectropolarimetric observations reveal for the first time unambiguous $U/I$
signals due to Hanle rotation in the Sr I line.


title: Photon frequency diffusion process

abstract:
  We introduce a stochastic multi-photon dynamics on reciprocal space. Assuming
isotropy, we derive the diffusion limit for a tagged photon to be a nonlinear
Markov process on frequency. The nonlinearity stems from the stimulated
emission. In the case of Compton scattering with thermal electrons, the
limiting process describes the dynamical fluctuations around the Kompaneets
equation. More generally, we construct a photon frequency diffusion process
which enables to include nonequilibrium effects. Modifications of the Planck
Law may thus be explored, where we focus on the low-frequency regime.


title:
Towards establishing the presence or absence of horizons in coalescing
  binaries of compact objects by using their gravitational wave signals

abstract:
  The quest for distinguishing black holes (BH) from horizonless compact
objects using gravitational wave (GW) signals from coalescing compact binaries
can be helped by utilizing the phenomenon of tidal heating (TH). This
phenomenon leaves its imprint on binary waveforms through the horizon
parameters. We investigate the effects of TH on GWs in order to probe the
observability of the horizon parameters. We mainly employ Fisher matrix
analysis to determine the errors and covariances between these parameters. The
horizon parameters were defined in a previous study (arXiv:2004.05974 [gr-qc])
as $H_1$ and $H_2$ for the two binary components, with $H_{1,2} \in [0,1]$.
They were further combined to form two new parameters, $H_{eff5}$ and
$H_{eff8}$, to minimize their covariances in parameter estimation studies. In
this work, we add the phase contribution due to TH in terms of $H_{eff5}$ and
$H_{eff8}$ to the TaylorF2 approximant, and examine the variation of their
measurement errors with the binary's total mass, mass ratio, luminosity
distance, and component spins. Since the Fisher matrix approach works well for
high SNR, we focus mainly on third-generation (3G) GW detectors Einstein
Telescope and Cosmic Explorer and use LIGO and Virgo for comparison. We find
that the region in the total binary mass where measurements of $H_{eff5}$ and
$H_{eff8}$ are most precise are $\sim 20 - 30M_\odot$ for LIGO-Virgo and $\sim
50 - 80M_\odot$ for 3G detectors. Spins of the binary components affect the
measurements of $H_{eff5}$ negligibly. In 3G detectors, Fisher analysis shows
that for mass ratio $1\lesssim q\lesssim 3 $ and total mass $10M_\odot\lesssim
M\lesssim 90M_\odot $, $H_{eff5}$ and $H_{eff8}$ can be measured with relative
percentage errors less than 40% and 90%, respectively, up to a distance of
1Gpc. We substantiate our results from Fisher studies with some Bayesian
simulations.


title: The Gaia-ESO Survey: The analysis of the hot-star spectra

abstract:
  The Gaia-ESO Survey (GES) is a large public spectroscopic survey that has
collected, over a period of 6 years, spectra of ~ 10^5 stars. This survey
provides not only the reduced spectra, but also the stellar parameters and
abundances resulting from the analysis of the spectra. The GES dataflow is
organised in 19 working groups. Working group 13 (WG13) is responsible for the
spectral analysis of the hottest stars (O, B and A type, with a formal cut-off
of Teff > 7000 K) that were observed as part of GES. We present the procedures
and techniques that have been applied to the reduced spectra, in order to
determine the stellar parameters and abundances of these stars. The procedure
used is similar to that of other working groups in GES. A number of groups
(called `Nodes') each independently analyse the spectra, using their
state-of-the-art techniques and codes. Specific for the analysis in WG13 is the
large temperature range that is covered (Teff = 7000 - 50,000 K), requiring the
use of different analysis codes. Most Nodes can therefore only handle part of
the data. Quality checks are applied to the results of these Nodes by comparing
them to benchmark stars, and by comparing them one to another. For each star
the Node values are then homogenised into a single result: the recommended
parameters and abundances. Eight Nodes each analysed (part of) the data. In
total 17,693 spectra of 6462 stars were analysed, most of them in 37 open star
clusters. The homogenisation led to stellar parameters for 5584 stars.
Abundances were determined for a more limited number of stars. Elements studied
are He, C, N, O, Ne, Mg, Al, Si and Sc. Abundances for at least one of those
elements were determined for 292 stars. The hot-star data analysed here, as
well as the Gaia-ESO Survey data in general, will be of considerable use in
future studies of stellar evolution and open clusters.


title:
Circuit Complexity for Thermofield Double States in Bosonic String
  Theory

abstract:
  In this paper, we first construct thermofield double states for bosonic
string theory in the light-cone gauge. We then obtain a coherent-thermal string
state and use it to calculate the circuit complexity in string theory. This is
done using the covariance matrix approach to calculate the circuit complexity.
In this approach, we will generate the optimal geodesics by a horizontal string
generator and, then, obtain the circuit complexity using the length of the
minimal geodesics in the group manifold.


title:
Steklov-Dirichlet spectrum: stability, optimization and continuity of
  eigenvalues

abstract:
  In this paper we study the Steklov-Dirichlet eigenvalues
$\lambda_k(\Omega,\Gamma_S)$, where $\Omega\subset \mathbb{R}^d$ is a domain
and $\Gamma_S\subset \partial \Omega$ is the subset of the boundary in which we
impose the Steklov conditions. After a first discussion about the regularity
properties of the Steklov-Dirichlet eigenfunctions we obtain a stability result
for the eigenvalues. We study the optimization problem under a measure
constraint on the set $\Gamma_S$, we prove the existence of a minimizer and the
non-existence of a maximizer. In the plane we prove a continuity result for the
eigenvalues imposing a bound on the number of connected components of the
sequence $\Gamma_{S,n}$, obtaining in this way a version of the famous result
of V. Sverak for the Steklov-Dirichlet eigenvalues. Using this result we prove
the existence of a maximizer under the same topological constraint and the
measure constraint.


title:
Structured illumination in Fresnel biprism-based digital holographic
  microscopy

abstract:
  The structured illumination (SI) architecture can be adopted in a digital
holographic (DH) microscope to enhance the spatial resolution. In this paper,
we propose and demonstrate a compact and simple SI method in a self-referencing
common-path configuration of DH microscopy. The combination of SI pattern
generated by a compact disk and common-path off-axis geometry formed by Fresnel
biprism introduces a low-cost and highly stable system to image both amplitude
and phase objects with a twofold improvement of the spatial resolution.
Experimental results for the case of a standard test sample validate the
predicted resolution enhancement compared to that of the conventional imager.
The presented DH method allows for imaging living cells with strikingly
improved clarity compared to the conventional DH microscopes.


title:
Scaling limits of random looptrees and bipartite plane maps with
  prescribed large faces

abstract:
  We first rephrase and unify known bijections between bipartite plane maps and
labelled trees with the formalism of looptrees, which we argue to be both more
relevant and technically simpler since the geometry of a looptree is explicitly
encoded by the depth-first walk (or {\L}ukasiewicz path) of the tree, as
opposed to the height or contour process for the tree. We then construct
continuum analogues associated with any c\`adl\`ag path with no negative jump
and derive several invariance principles. We especially focus on uniformly
random looptrees and maps with prescribed face degrees and study their scaling
limits in the presence of macroscopic faces, which complements a previous work
in the case of no large faces. The limits (along subsequences for maps) form
new families of random metric measured spaces related to processes with
exchangeable increments with no negative jumps and our results generalise
previous works which concerned the Brownian and stable L\'evy bridges.


title:
Gentle patterning approaches towards compatibility with bio-organic
  materials and their environmental aspects

abstract:
  Advances in material science, bio-electronic, and implantable medicine
combined with recent requests for eco-friendly materials and technologies
inevitably formulate new challenges for nano- and micro-patterning techniques.
Overall, the importance of creating micro and nanostructures is motivated by a
large manifold of fundamental and applied properties accessible only at the
nanoscale. Lithography is a crucial family of fabrication methods to create
prototypes and produce devices on an industrial scale. The pure trend in the
miniaturization of critical electronic semiconducting components is recently
enhanced by implementing bio-organic systems in electronics. So far,
significant efforts have been made to find novel lithographic approaches and
develop old ones to reach compatibility with delicate bio-organic systems and
minimize the impact on the environment. Herein, we briefly review such delicate
materials and sophisticated patterning techniques.


title:
Dissipative Tunneling Rates through the Incorporation of
  First-Principles Electronic Friction in Instanton Rate Theory I: Theory

abstract:
  Reactions involving adsorbates on metallic surfaces and impurities in bulk
metals are ubiquitous in a wide range of technological applications. The
theoretical modelling of such reactions presents a formidable challenge for
theory because nuclear quantum effects (NQEs) can play a prominent role and the
coupling of the atomic motion with the electrons in the metal gives rise to
important non-adiabatic effects (NAEs) that alter atomic dynamics. In this
work, we derive a theoretical framework that captures both NQEs and NAEs and,
due to its high efficiency, can be applied to first-principles calculations of
reaction rates in high-dimensional realistic systems. In more detail, we
develop a method that we coin ring polymer instanton with explicit friction
(RPI-EF), starting from the ring-polymer instanton formalism applied to a
system-bath model. We derive general equations that incorporate the spatial and
frequency dependence of the friction tensor, and then combine this method with
the \textit{ab initio} electronic friction formalism for the calculation of
thermal reaction rates. We show that the connection between RPI-EF and the form
of the electronic friction tensor presented in this work does not require any
further approximations, and it is expected to be valid as long as the
approximations of both underlying theories remain valid.


title:
PACSafe: Leveraging ARM Pointer Authentication for Memory Safety in
  C/C++

abstract:
  Memory safety bugs remain in the top ranks of security vulnerabilities, even
after decades of research on their detection and prevention. Various
mitigations have been proposed for C/C++, ranging from language dialects to
instrumentation. Among these, compiler-based instrumentation is particularly
promising, not requiring manual code modifications and being able to achieve
precise memory safety. Unfortunately, existing compiler-based solutions
compromise in many areas, including performance but also usability and memory
safety guarantees. New developments in hardware can help improve performance
and security of compiler-based memory safety. ARM Pointer Authentication, added
in the ARMv8.3 architecture, is intended to enable hardware-assisted Control
Flow Integrity. But since its operations are relatively generic, it also
enables other, more comprehensive hardware-supported runtime integrity
approaches. As such, we propose PACSafe, a memory safety approach based on ARM
Pointer Authentication. PACSafe uses pointer signatures to retrofit full memory
safety to C/C++ programs, protecting heap, stack, and globals against temporal
and spatial vulnerabilities. We present a full, LLVM-based prototype
implementation, running on an M1 MacBook Pro, i.e., on actual ARMv8.3 hardware.
Our prototype evaluation shows that the system outperforms similar approaches
under real-world conditions. This, together with its compatibility with
uninstrumented libraries and cryptographic protection against attacks on
metadata, makes PACSafe a viable solution for retrofitting memory safety to
C/C++ programs.


title: Domain Randomization for Object Counting

abstract:
  Recently, the use of synthetic datasets based on game engines has been shown
to improve the performance of several tasks in computer vision. However, these
datasets are typically only appropriate for the specific domains depicted in
computer games, such as urban scenes involving vehicles and people. In this
paper, we present an approach to generate synthetic datasets for object
counting for any domain without the need for photo-realistic techniques
manually generated by expensive teams of 3D artists. We introduce a domain
randomization approach for object counting based on synthetic datasets that are
quick and inexpensive to generate. We deliberately avoid photorealism and
drastically increase the variability of the dataset, producing images with
random textures and 3D transformations, which improves generalization.
Experiments show that our method facilitates good performance on various real
word object counting datasets for multiple domains: people, vehicles, penguins,
and fruit. The source code is available at: https://github.com/enric1994/dr4oc


title:
SiGMa-Net: Deep learning network to distinguish binary black hole
  signals from short-duration noise transients

abstract:
  Blip glitches, a type of short-duration noise transient in the LIGO--Virgo
data, are a nuisance for the binary black hole (BBH) searches. They affect the
BBH search sensitivity significantly because their time-domain morphologies are
very similar, and that creates difficulty in vetoing them. In this work, we
construct a deep-learning neural network to efficiently distinguish BBH signals
from blip glitches. We introduce sine-Gaussian projection (SGP) maps, which are
projections of GW frequency-domain data snippets on a basis of sine-Gaussians
defined by the quality factor and central frequency. We feed the SGP maps to
our deep-learning neural network, which classifies the BBH signals and blips.
Whereas the BBH signals are simulated, the blips used are taken from real data
throughout our analysis. We show that our network significantly improves the
identification of the BBH signals in comparison to the results obtained using
traditional-$\chi^2$ and sine-Gaussian $\chi^2$. For example, our network
improves the sensitivity by 75% at a false-positive rate of $10^{-2}$ for BBHs
with total mass in the range $[80,140]~M_{\odot}$ and SNR in the range $[3,8]$.
Also, it correctly identifies 95% of the real GW events in GWTC-3. The
computation time for classification is a few minutes for thousands of SGP maps
on a single core. With further optimisation in the next version of our
algorithm, we expect a further reduction in the computational cost. Our
proposed method can potentially improve the veto process in the LIGO--Virgo GW
data analysis and conceivably support identifying GW signals in low-latency
pipelines.


title: Tadpole Cosmology: Self Tuning Without Degeneracy

abstract:
  Degeneracy is a method to accommodate exact, low energy vacuum states in
scalar-tensor gravitational models despite the presence of an arbitrarily large
vacuum energy. However, this approach requires very particular combinations of
scalar field and metric couplings in the Lagrangian. In this work we study
departures from the restrictive degeneracy condition -- starting from a
fiducial model containing an exact Minkowski space solution, we break the
degeneracy condition in numerous simple ways to test if the resulting models
maintain certain key features -- specifically the dynamical cancellation of a
large vacuum energy by the scalar field and the existence of a low energy
vacuum state. We highlight the role the tadpole plays in eliminating the fixed
points of the dynamical system, generically rendering both the scalar field and
metric time dependent. Our results indicate that when violating the degeneracy
condition but preserving shift symmetry, the metric maintains an asymptotic
Minkowski state, irrespective of the presence of the cosmological constant. In
contrast, when shift symmetry is also broken the asymptotic behaviour can
radically alter. Regardless, the non-degenerate models in this work share an
attractive quality; harboring low energy, late-time asymptotic states that are
independent of the vacuum energy. The tadpole allows for a broader class of
non-degenerate, self-tuning models than was previously realized.


title:
Can a binary neutron star merger in the vicinity of a supermassive black
  hole enable a detection of a post-merger gravitational wave signal?

abstract:
  The postmerger gravitational-wave (GW) signal of a binary neutron star (BNS)
merger is expected to contain valuable information that could shed light on the
equation of state (EOS) of NSs, the properties of the matter produced during
the merger, as well as the nature of any potential intermediate merger product
such as hypermassive or supramassive NSs. However, the postmerger lies in the
high frequency regime ($ \gtrsim 1000 $ Hz) where current LIGO-Virgo detectors
are insensitive. While proposed detectors such as NEMO, Cosmic Explorer and
Einstein Telescope could potentially detect the postmerger for BNSs within
$\mathcal{O}(10~\mathrm{Mpc})$, such events are likely to be rare. In this
work, we speculate on the possibility of detecting the postmerger from BNSs
coalescing in the vicinity of supermassive black holes (SMBH). The redshift
produced by the gravitational field of the SMBH, as well as the BNS's proper
motion around the SMBH, could effectively "stretch" the postmerger signal into
the band of the detectors. We demonstrate, using a phenomenological model, that
such BNS coalescences would enable constraints on the peak of the postmerger
signal that would otherwise have not been possible, provided the degree of
redshifting due to the SMBH can be independently acquired. We further show how
such mergers would improve EOS model selection using the postmerger signal. We
discuss the mechanisms that might deliver such events, and the limitations of
this work.


title:
Measuring Trustworthiness or Automating Physiognomy? A Comment on Safra,
  Chevallier, Gr\`ezes, and Baumard (2020)

abstract:
  Interpersonal trust - a shared display of confidence and vulnerability toward
other individuals - can be seen as instrumental in the development of human
societies. Safra, Chevallier, Gr\`ezes, and Baumard (2020) studied the
historical progression of interpersonal trust by training a machine learning
(ML) algorithm to generate trustworthiness ratings of historical portraits,
based on facial features. They reported that trustworthiness ratings of
portraits dated between 1500--2000CE increased with time, claiming that this
evidenced a broader increase in interpersonal trust coinciding with several
metrics of societal progress. We argue that these claims are confounded by
several methodological and analytical issues and highlight troubling parallels
between Safra et al.'s algorithm and the pseudoscience of physiognomy. We
discuss the implications and potential real-world consequences of these issues
in further detail.


title: Winograd Convolution: A Perspective from Fault Tolerance

abstract:
  Winograd convolution is originally proposed to reduce the computing overhead
by converting multiplication in neural network (NN) with addition via linear
transformation. Other than the computing efficiency, we observe its great
potential in improving NN fault tolerance and evaluate its fault tolerance
comprehensively for the first time. Then, we explore the use of fault tolerance
of winograd convolution for either fault-tolerant or energy-efficient NN
processing. According to our experiments, winograd convolution can be utilized
to reduce fault-tolerant design overhead by 27.49\% or energy consumption by
7.19\% without any accuracy loss compared to that without being aware of the
fault tolerance


title:
Inclusive nonresonant multilepton probes of new phenomena at $\sqrt{s}$
  = 13 TeV

abstract:
  An inclusive search for nonresonant signatures of beyond the standard model
(SM) phenomena in events with three or more charged leptons, including
hadronically decaying $\tau$ leptons, is presented. The analysis is based on a
data sample corresponding to an integrated luminosity of 138 fb$^{-1}$ of
proton-proton collisions at $\sqrt{s}$ = 13 TeV, collected by the CMS
experiment at the LHC in 2016-2018. Events are categorized based on the lepton
and b-tagged jet multiplicities and various kinematic variables. Three
scenarios of physics beyond the SM are probed, and signal-specific boosted
decision trees are used for enhancing sensitivity. No significant deviations
from the background expectations are observed. Lower limits are set at 95%
confidence level on the mass of type-III seesaw heavy fermions in the range
845-1065 GeV for various decay branching fraction combinations to SM leptons.
Doublet and singlet vector-like $\tau$ lepton extensions of the SM are excluded
for masses below 1045 GeV and in the mass range 125-150 GeV, respectively.
Scalar leptoquarks decaying exclusively to a top quark and a lepton are
excluded below 1.12-1.42 TeV, depending on the lepton flavor. For the type-III
seesaw as well as the vector-like doublet model, these constraints are the most
stringent to date. For the vector-like singlet model, these are the first
constraints from the LHC experiments. Detailed results are also presented to
facilitate alternative theoretical interpretations.


title: Periods of families of curves in threefolds

abstract:
  Clemens' conjecture states that the the number of rational curve in a generic
quintic threefold is finite. If it is false we prove that certain periods of
rational curves in such a quintic threefold must vanish. Our method is based on
a generalization of a proof of Max Noether's theorem using infinitesimal
variation of Hodge structures and its reformulation in terms of integrals and
Gauss-Manin connection.


title: The ultra-diffuse galaxy AGC 114905 needs dark matter

abstract:
  Recent 21 cm line observations of the ultra-diffuse galaxy AGC~114905
indicate a rotating disc largely supported against gravity by orbital motion,
as usual. Remarkably, this study has revealed that the form and amplitude of
the HI rotation curve is completely accounted for by the observed distribution
of baryonic matter, stars and neutral gas, implying that no dark halo is
required. It is surprising to find a DM-free galaxy for a number of reasons,
one being that a bare Newtonian disk having low velocity dispersion would be
expected to be unstable to both axi- and non-axisymmetric perturbations that
would change the structure of the disc on a dynamical timescale, as has been
known for decades. We present $N$-body simulations of the DM-free model, and
one having a low-density DM halo, that confirm this expectation: the disc is
chronically unstable to just such instabilities. Since it is unlikely that a
galaxy that is observed to have a near-regular velocity pattern would be
unstable, our finding calls into question the suggestion that the galaxy may
lack, or have little, dark matter. We also show that if the inclination of this
near face-on system has been substantially overestimated, the consequent
increased amplitude of the rotation curve would accommodate a halo massive
enough for the galaxy to be stable.


title:
Where Is My Training Bottleneck? Hidden Trade-Offs in Deep Learning
  Preprocessing Pipelines

abstract:
  Preprocessing pipelines in deep learning aim to provide sufficient data
throughput to keep the training processes busy. Maximizing resource utilization
is becoming more challenging as the throughput of training processes increases
with hardware innovations (e.g., faster GPUs, TPUs, and inter-connects) and
advanced parallelization techniques that yield better scalability. At the same
time, the amount of training data needed in order to train increasingly complex
models is growing. As a consequence of this development, data preprocessing and
provisioning are becoming a severe bottleneck in end-to-end deep learning
pipelines.
  In this paper, we provide an in-depth analysis of data preprocessing
pipelines from four different machine learning domains. We introduce a new
perspective on efficiently preparing datasets for end-to-end deep learning
pipelines and extract individual trade-offs to optimize throughput,
preprocessing time, and storage consumption. Additionally, we provide an
open-source profiling library that can automatically decide on a suitable
preprocessing strategy to maximize throughput. By applying our generated
insights to real-world use-cases, we obtain an increased throughput of 3x to
13x compared to an untuned system while keeping the pipeline functionally
identical. These findings show the enormous potential of data pipeline tuning.


title: Synthetic data for unsupervised polyp segmentation

abstract:
  Deep learning has shown excellent performance in analysing medical images.
However, datasets are difficult to obtain due privacy issues, standardization
problems, and lack of annotations. We address these problems by producing
realistic synthetic images using a combination of 3D technologies and
generative adversarial networks. We use zero annotations from medical
professionals in our pipeline. Our fully unsupervised method achieves promising
results on five real polyp segmentation datasets. As a part of this study we
release Synth-Colon, an entirely synthetic dataset that includes 20000
realistic colon images and additional details about depth and 3D geometry:
https://enric1994.github.io/synth-colon


title:
Dissipative Tunneling Rates through the Incorporation of
  First-Principles Electronic Friction in Instanton Rate Theory II: Benchmarks
  and Applications

abstract:
  In part I, we presented the ring-polymer instanton with explicit friction
(RPI-EF) method and showed how it can be connected to the \textit{ab initio}
electronic friction formalism. This framework allows the calculation of
tunneling reaction rates that incorporate the quantum nature of the nuclei and
certain types of non-adiabatic effects (NAEs) present in metals. In this second
part, we analyze the performance of RPI-EF on model potentials and apply it to
realistic systems. For a 1D double-well model, we benchmark the method against
numerically exact results obtained from multi-layer multi-configuration
time-dependent Hartree calculations. We demonstrate that RPI-EF is accurate for
medium and high friction strengths and less accurate for extremely low friction
values. We also show quantitatively how the inclusion of NAEs lowers the
cross-over temperature into the deep tunneling regime, reduces the tunneling
rates, and in certain regimes, steers the quantum dynamics by modifying the
tunneling pathways. As a showcase of the efficiency of this method, we present
a study of hydrogen and deuterium hopping between neighboring interstitial
sites in selected bulk metals. The results show that multidimensional
vibrational coupling and nuclear quantum effects have a larger impact than NAEs
on the tunneling rates of diffusion in metals. Together with part I, these
results advance the calculations of dissipative tunneling rates from first
principles.


title:
End-to-end Neuron Instance Segmentation based on Weakly Supervised
  Efficient UNet and Morphological Post-processing

abstract:
  Recent studies have demonstrated the superiority of deep learning in medical
image analysis, especially in cell instance segmentation, a fundamental step
for many biological studies. However, the good performance of the neural
networks requires training on large unbiased dataset and annotations, which is
labor-intensive and expertise-demanding. In this paper, we present an
end-to-end weakly-supervised framework to automatically detect and segment NeuN
stained neuronal cells on histological images using only point annotations. We
integrate the state-of-the-art network, EfficientNet, into our U-Net-like
architecture. Validation results show the superiority of our model compared to
other recent methods. In addition, we investigated multiple post-processing
schemes and proposed an original strategy to convert the probability map into
segmented instances using ultimate erosion and dynamic reconstruction. This
approach is easy to configure and outperforms other classical post-processing
techniques.


title: Hamilton-Ivey estimates for the Ricci-Bourguignon flow with $\rho<0$

abstract:
  In this paper, we prove Hamilton-Ivey estimates for the Ricci-Bourguignon
flow on a compact manifold, with $n=3$ and $\rho<0$. As a consequence, we prove
that compact ancient solutions have nonnegative sectional curvature for all
negative $\rho$.


title:
Corner Structure of Four-Dimensional General Relativity in the Coframe
  Formalism

abstract:
  This note describes a local Poisson structure (up to homotopy) associated to
corners in four-dimensional gravity in the coframe (Palatini--Cartan)
formalism. This is achieved through the use of the BFV formalism. The corner
structure contains in particular an Atiyah algebroid that couples the internal
symmetries to diffeomorphisms. The relation with $BF$ theory is also described.

categories: math-ph gr-qc hep-th math.MP math.QA math.SG


title:
Is first-order relativistic hydrodynamics in general frame stable and
  causal for arbitrary interaction?

abstract:
  We derive a first-order, stable and causal, relativistic hydrodynamic theory
from the microscopic kinetic equation using the gradient expansion technique in
a general frame. The general frame is introduced from the arbitrary matching
conditions for hydrodynamic fields. The interaction is introduced in the
relativistic Boltzmann equation through momentum-dependent relaxation time
approximation (MDRTA). We demonstrate here for the first time that not only the
general frame choice but also the momentum dependence of microscopic
interaction rate, captured through MDRTA, is imperative for producing the
essential field corrections that give rise to a causal and stable first-order
theory.


title:
Necessary and sufficient condition for a generic 3R serial manipulator
  to be cuspidal

abstract:
  Cuspidal robots can travel from one inverse kinematic solution to another
without meeting a singularity. The name cuspidal was coined based on the
existence of a cusp point in the workspace of 3R serial robots. The existence
of a cusp point was proved to be a necessary and sufficient condition for
orthogonal robots to be cuspidal, but it was not possible to extend this
condition to non-orthogonal robots. The goal of this paper is to prove that
this condition stands for any generic 3R robot. This result would give the
designer more flexibility. In the presented work, the geometrical
interpretation of the inverse kinematics of 3R robots is revisited and
important observations on the nonsingular change of posture are noted. The
paper presents a theorem regarding the existence of reduced aspects in any
generic 3R serial robot. Based on these observations and on this theorem, we
prove that the existence of a cusp point is a necessary and sufficient
condition for any 3R generic robot to be cuspidal.


title: Term Rewriting Based On Set Automaton Matching

abstract:
  In previous work we have proposed an efficient pattern matching algorithm
based on the notion of set automaton. In this article we investigate how set
automata can be exploited to implement efficient term rewriting procedures.
These procedures interleave pattern matching steps and rewriting steps and thus
smoothly integrate redex discovery and subterm replacement. Concretely, we
propose an optimised algorithm for outermost rewriting of left-linear term
rewriting systems, prove its correctness, and present the results of some
implementation experiments.


title: Improved Optimal Testing Results from Global Hypercontractivity

abstract:
  The problem of testing low-degree polynomials has received significant
attention over the years due to its importance in theoretical computer science,
and in particular in complexity theory. The problem is specified by three
parameters: field size $q$, degree $d$ and proximity parameter $\delta$, and
the goal is to design a tester making as few as possible queries to a given
function, which is able to distinguish between the case the given function has
degree at most $d$, and the case the given function is $\delta$-far from any
degree $d$ function.
  A tester is called optimal if it makes $O(q^d+1/\delta)$ queries (which are
known to be necessary). For the field of size $q$, the natural $t$-flat tester
was shown to be optimal first by Bhattacharyya et al. for $q=2$, and later by
Haramaty et al. for all prime powers $q$. The dependency on the field size,
however, is a tower-type function.
  We improve the results above, showing that the dependency on the field size
is polynomial. Our approach also applies in the more general setting of lifted
affine invariant codes, and is based on studying the structure of the
collection of erroneous subspaces. i.e. subspaces $A$ such that $f|_{A}$ has
degree greater than $d$. Towards this end, we observe that these sets are
poorly expanding in the affine version of the Grassmann graph and use that to
establish structural results on them via global hypercontractivity. We then use
this structure to perform local correction on $f$.


title: Weak energy shaping for stochastic controlled port-Hamiltonian systems

abstract:
  The present work address the problem of energy shaping for stochastic
port-Hamiltonian system. Energy shaping is a powerful technique that allows to
systematically find feedback law to shape the Hamiltonian of a controlled
system so that, under a general passivity condition, it converges or tracks a
desired configuration. Energy shaping has been recently generalized to consider
stochastic port-Hamiltonian system. Nonetheless the resulting theory presents
several limitation in the application so that relevant examples, such as the
additive noise case, are immediately ruled out from the possible application of
energy shaping. The current paper continues the investigation of the properties
of a weak notion of passivity for a stochastic system and a consequent weak
notion of convergence for the shaped system considered recently by the authors.
Such weak notion of passivity is strictly related to the existence and
uniqueness of an invariant measure for the system so that the theory developed
has a purely probabilistic flavour. We will show how all the relevant results
of energy shaping can be recover under the weak setting developed. We will also
show how the weak passivity setting considered draw an insightful connection
between stochastic port-Hamiltonian systems and infinite-dimensional
port-Hamiltonian system.


title: Zeptonewton force sensing with squeezed quadratic optomechanics

abstract:
  Cavity optomechanical (COM) sensors, as powerful tools for measuring
ultraweak forces or searching for dark matter, have been implemented to date
mainly using linear COM couplings. Here, quantum force sensing is explored by
using a quadratic COM system which is free of bistability and allows accurate
measurement of mechanical energy. We find that this system can be optimized to
achieve a force sensitivity $7$ orders of magnitude higher than any
conventional linear COM sensor, with experimentally accessible parameters.
Further integrating a quadratic COM system with a squeezing medium can lead to
another $3$ orders enhancement, well below the standard quantum limit and
reaching the zeptonewton level. This opens new prospects of making and using
quantum nonlinear COM sensors in fundamental physics experiments and in a wide
range of applications requiring extreme sensitivity.


title: Non-linear stiffness behavior of planar serial robotic manipulators

abstract:
  The paper focuses on the stiffness analysis of multi-link serial planar
manipulators, which may demonstrate nonlinear stiffness behavior under the
compressive loading. Two important cases are considered, where the manipulator
has either a straight or non-straight initial configuration. It was proved that
in the first case the loading may cause the buckling if it exceeds some
critical value, and the manipulator suddenly changes its straight shape and
stiffness properties. For computing this critical force, a general
eigenvalue-based technique was proposed that can be applied to any multi-link
serial manipulator. For the second case dealing with non-straight initial
configurations, a universal energy-based technique was applied that allowed to
detect quasi-buckling phenomenon when it is observed very fast but not instant
change of the manipulator shape and its stiffness coefficient under the
loading. These results are illustrated by numerous examples of non-linear
stiffness behavior of three-and four-link manipulators that are subjected to
compressive force.


title: A study of deep perceptual metrics for image quality assessment

abstract:
  Several metrics exist to quantify the similarity between images, but they are
inefficient when it comes to measure the similarity of highly distorted images.
In this work, we propose to empirically investigate perceptual metrics based on
deep neural networks for tackling the Image Quality Assessment (IQA) task. We
study deep perceptual metrics according to different hyperparameters like the
network's architecture or training procedure. Finally, we propose our
multi-resolution perceptual metric (MR-Perceptual), that allows us to aggregate
perceptual information at different resolutions and outperforms standard
perceptual metrics on IQA tasks with varying image deformations. Our code is
available at https://github.com/ENSTA-U2IS/MR_perceptual


title: On Estimates for Maximal Operators Associated with Tangential Regions

abstract:
  The thesis comprises three chapters.
  Chapter 1 investigates generalizations of the theorem of Fatou for
convolution type integral operators with general approximate identities. It is
introduced $\lambda(r)$-convergence, which is a generalization of
non-tangential convergence in the unit disc. The connections between general
approximate identities and optimal convergence regions for such operators are
described in different functional spaces.
  Chapter 2 studies some generalizations of the theorem of Littlewood, which
makes an important complement to the theorem of Fatou, constructing analytic
function possessing almost everywhere divergent property along a given
tangential curve. The same convolution type integral operators are considered
with more general kernels than approximate identities. Two kinds of
generalizations of the theorem of Littlewood are obtained, possessing
everywhere divergent property.
  Chapter 3 is devoted to some questions of equivalency of differentiation
bases in $\mathbb{R}^n$. The complete equivalence of basis of rare dyadic
rectangles and the basis of complete dyadic rectangles in $\mathbb{R}^2$ is
investigated. Besides, it is introduced quasi-equivalence between two
differentiation bases in $\mathbb{R}^n$ and is considered the set of functions
that such bases differentiate.


title:
Exact Two-Body Solutions and Quantum Defect Theory of Polar Molecular
  Gases with Van der Waals Potentials

abstract:
  In a recent experiment [Matsuda et al, Science 370, 1324 (2020)], a quasi
two-dimensional (2D), long-lived and strongly interacting diatomic polar
molecular gas was successfully prepared via controllable electric field
technique. Surprisingly, the effective repulsive and attractive Van der Waals
interactions of two molecules would emerge when scanning the strength of the
electric fields. Those results were also generalized to the three-dimensional
(3D) case in a later experiment [J. Li et al, Nature Physics 17, 1144 (2021)].
Motivated by these experiments, in this paper we provide the two-body exact
solutions for the 2D and 3D Schr\"{o}dinger equation with isotropic Van der
Waals potentials ($\pm1/r^{6}$). Furthermore, base on these exact solutions, we
build the analytical quantum defect theory (QDT) for quasi-2D and 3D
geometries, and then apply QDT to study the scattering properties and bound
states of two ultracold polar molecules confined in quasi-2D and 3D geometries.
Interestingly, we find that for the attractive (repulsive) Van der Waals
potential cases, the two-body short range potential can be approximated by an
square barrier with infinity height (square potential with finite depth) which
yields the wide (narrow) and dense (dilute) resonances of the quantum defect
parameter. For the quasi-2D attractive case, the scattering resonances of
different partial waves can orderly happen which is featured by the phase jumps
when varying the scattering energy. The analytical expansions in the low energy
limit shows a consistent agreement to the numerical results.


title:
Article's Scientific Prestige: measuring the impact of individual
  articles in the Web of Science

abstract:
  We performed a citation analysis on the Web of Science publications
consisting of more than 63 million articles and 1.45 billion citations on 254
subjects from 1981 to 2020. We proposed the Article's Scientific Prestige (ASP)
metric and compared this metric to number of citations (#Cit) and journal grade
in measuring the scientific impact of individual articles in the large-scale
hierarchical and multi-disciplined citation network. In contrast to #Cit, ASP,
that is computed based on the eigenvector centrality, considers both direct and
indirect citations, and provides steady-state evaluation cross different
disciplines. We found that ASP and #Cit are not aligned for most articles, with
a growing mismatch amongst the less cited articles. While both metrics are
reliable for evaluating the prestige of articles such as Nobel Prize winning
articles, ASP tends to provide more persuasive rankings than #Cit when the
articles are not highly cited. The journal grade, that is eventually determined
by a few highly cited articles, is unable to properly reflect the scientific
impact of individual articles. The number of references and coauthors are less
relevant to scientific impact, but subjects do make a difference.


title:
Conscious Commerce -- Digital Nudging and Sustainable E-commerce
  Purchase Decisions

abstract:
  So-called 'fast fashion' consumption, amplified through cost-effective
e-commerce, constitutes a major factor negatively impacting climate change. A
recently noted strategy to motivate consumers to more sustainable decisions is
digital nudging. This paper explores the capability of digital nudging in the
context of green fashion e-commerce. To do so, digital default and social norm
nudges are tested in an experimental setting of green fashion purchases. An
online experiment (n=320) was conducted, simulating an online retail scenario.
Results failed to show statistically significant relationships between nudging
strategies and purchase decisions. However, explorative analyses show a
backfiring effect for the combination of nudges and thus, reveal a hitherto
neglected impact of participants' identification on the effectiveness of the
digital nudging strategies. Consequently, this study contributes to digital
nudging literature and informs practice with new insights on effective choice
architectures in e-commerce.


title:
Distance learning as innovation technology of school geographical
  education

abstract:
  The article substantiates the necessity of using innovative technologies in
the process of studying and teaching geographical disciplines at secondary
schools. Particular attention is paid to distance learning as a pedagogical
innovation, its theoretical aspects and the ways of its introduction into the
educational process. The relevance of using distance learning at the New
Ukrainian School is proved. Its advantages and disadvantages are revealed. The
examples of some forms of distance learning that will contribute to
geographical competence development according to European requirements are
provided. The article particularly focuses on the Massive Open Online Courses,
modern websites, virtual portals of individual teachers, LearningApps.org
portal, and Moodle.