title: An inverted crossover resonance within one Zeeman manifold

abstract:
  We carry out investigations of inverted crossover resonances in $\pi$-driven
four-level systems where $\Delta F$ can be zero. Through the use of sub-Doppler
frequency modulation spectroscopy of the $(6s^{2})$ $^{1}S_{0}$ $-$ $(6s6p)$
$^{3}P_{1}$ transition in $^{171}$Yb the resonance becomes manifest. The
centre-frequency is inherently insensitive to first-order Zeeman shifts and
equates to the two-level resonance frequency in the absence of a magnetic
field. A rate equation model is used to help validate the nature of the
resonance. Optical frequency measurements of the $F'=1/2$ hyperfine line
recorded over two months demonstrate a statistical uncertainty of
$2\times10^{-11}$. The inverted crossover resonance found with the $F'=3/2$
line is used for 556 nm laser frequency stabilization, which is an alternative
means when applied to magneto-optical trapping of $^{171}$Yb.


title:
Analysis of the $Y(4220)$ and $Y(4390)$ as molecular states with QCD sum
  rules

abstract:
  In this article, we assign the $Y(4390)$ and $Y(4220)$ to be the vector
molecular states $D\bar{D}_1(2420)$ and $D^*\bar{D}_0^*(2400)$, respectively,
and study their masses and pole residues with the QCD sum rules in details. The
present calculations only favor assigning the $Y(4390)$ to be the
$D\bar{D}_1(1^{--})$ molecular state.


title: Helly-type theorem for eigenvectors

abstract:
  We prove that if any $\lfloor3d/2 \rfloor$ or fewer elements of a finite
family of linear operators $\mathbb K^d\to \mathbb K^d$ ($\mathbb K$ is an
arbitrary field) have a common eigenvector then all operators in the family
have a common eigenvector. Moreover, $\lfloor 3d/2\rfloor$ cannot be replaced
by a smaller number. Also, we study the following problem, achieving partial
results: prove that if any $l=O(d)$ or fewer elements of a finite family of
linear operators $\mathbb K^d\to \mathbb K^d$ have a common non-trivial
invariant subspace then all operators in the family have a common non-trivial
invariant subspace.


title:
Reduce positive and negative falses from attacks collected from the
  deployment of distributed honeypot network

abstract:
  Current tools and systems of detecting vulnerabilities simply alert the
administrator of attempted attacks against his network or system. However,
generally, the huge number of alerts to analyze and the amount time required to
update security rules after analyzing alerts provides time and opportunity for
the attacker to inflict damages. Moreover, most of these tools generate
positive and negative falses, which may be important to the attacked network.
Otherwise, many solutions exist such as IPS, but it shows a great defect due,
fundamentally, to false positives. Indeed, attackers often make IPS block a
legitimate traffic when they detect its presence in the attacked network. In
this paper we describe an automated algorithm that gives the ability to detect
attacks before they occurrence, then reduce positive and negative falses rates.
Moreover, we use a set of data related to malicious traffic captured using a
network of honeypots to recognize potential threats sources.


title: Constrained Submodular Maximization via a Non-symmetric Technique

abstract:
  The study of combinatorial optimization problems with a submodular objective
has attracted much attention in recent years. Such problems are important in
both theory and practice because their objective functions are very general.
Obtaining further improvements for many submodular maximization problems boils
down to finding better algorithms for optimizing a relaxation of them known as
the multilinear extension.
  In this work we present an algorithm for optimizing the multilinear
relaxation whose guarantee improves over the guarantee of the best previous
algorithm (which was given by Ene and Nguyen (2016)). Moreover, our algorithm
is based on a new technique which is, arguably, simpler and more natural for
the problem at hand. In a nutshell, previous algorithms for this problem rely
on symmetry properties which are natural only in the absence of a constraint.
Our technique avoids the need to resort to such properties, and thus, seems to
be a better fit for constrained problems.


title:
When Engagement Meets Similarity: Efficient (k,r)-Core Computation on
  Social Networks

abstract:
  In this paper, we investigate the problem of (k,r)-core which intends to find
cohesive subgraphs on social networks considering both user engagement and
similarity perspectives. In particular, we adopt the popular concept of k-core
to guarantee the engagement of the users (vertices) in a group (subgraph) where
each vertex in a (k,r)-core connects to at least k other vertices. Meanwhile,
we also consider the pairwise similarity between users based on their profiles.
For a given similarity metric and a similarity threshold r, the similarity
between any two vertices in a (k,r)-core is ensured not less than r. Efficient
algorithms are proposed to enumerate all maximal (k,r)-cores and find the
maximum (k,r)-core, where both problems are shown to be NP-hard. Effective
pruning techniques significantly reduce the search space of two algorithms and
a novel (k,k')-core based (k,r)-core size upper bound enhances performance of
the maximum (k,r)-core computation. We also devise effective search orders to
accommodate the different nature of two mining algorithms. Comprehensive
experiments on real-life data demonstrate that the maximal/maximum (k,r)-cores
enable us to find interesting cohesive subgraphs, and performance of two mining
algorithms is significantly improved by proposed techniques.


title: Heavy Quark Coupled Channel Dynamics from Thermal Shifts

abstract:
  QCD at finite temperature below the phase transition should be determined in
terms of colour singlet states such as hadrons and strings. We show how
quark-hadron duality allows extracting sensible information concerning heavy
quark and string breaking coupled channel dynamics from Polyakov loop
correlators.


title:
High-scale leptogenesis with three-loop neutrino mass generation and
  dark matter

abstract:
  We demonstrate a common origin for high-scale leptogenesis and three-loop
neutrino mass generation. Specifically we extend the standard model by two real
singlet scalars, two singly charged scalars carrying different lepton numbers
and two or more singlet fermions with Majorana masses. Our model respects a
softly broken lepton number and an exactly conserved $Z_2^{}$ discrete
symmetry. Through the lepton-number-violating decays of the real scalars and
then the lepton-number-conserving decays of the charged scalars, we can obtain
a lepton asymmetry stored in the standard model leptons. This lepton asymmetry
can be partially converted to a baryon asymmetry by the sphaleron processes.
The interactions for this leptogenesis can also result in a three-loop diagram
to generate the neutrino masses. The lightest singlet fermion can keep stable
to serve as a dark matter particle.


title:
HST/WFC3 Observations of Uranus' 2014 storm clouds and comparison with
  VLT/SINFONI and IRTF/SpeX observations

abstract:
  Observations of Uranus were made on the 8/9th November with HST/WFC3 at a
time when a huge cloud complex was present at 30 - 40N. We imaged Uranus in
seven filters spanning 467 - 924 nm, and analysed these observations with the
NEMESIS radiative-transfer and retrieval code.
  The same system was also observed in the H-band with VLT/SINFONI ON 31st
October and 11th November (Irwin et al., 2016). To constrain the background
cloud particle sizes and scattering properties we conducted a limb-darkening
analysis of the background cloud structure at 30-40N by simultaneously fitting:
a) these HST/OPAL observations at a range of zenith angles; b) the VLT/SINFONI
observations at a range of zenith angles; and c) IRTF/SpeX observations made in
2009 (Irwin et al., 2015).
  We find that the observations are well modelled with a three-component cloud
comprised of: 1) a vertically thin, but optically thick 'deep' tropospheric
cloud at a pressure of ~2 bars; 2) a methane-ice cloud at the
methane-condensation level with variable vertical extent; and 3) a vertically
extended tropospheric haze. We find that the particles sizes in both haze and
tropospheric cloud have an effective radius of ~0.1 micron, although we cannot
rule out larger particle sizes in the tropospheric cloud.
  We find that the particles in both the tropospheric cloud and haze are more
scattering at short wavelengths, giving them a blue colour, but are more
absorbing at longer wavelengths, especially for the tropospheric haze. For the
particles in the storm clouds, which we assume to be composed of methane ice
particles, we find that their mean radii must be ~0.5 micron. We find that the
high clouds have low integrated opacity, and that "streamers" reminiscent of
thunderstorm anvils are confined to levels deeper than 1 bar. These results
argue against vigorous moist convective origins for the cloud features.


title:
Non-Hermitian Acoustic Metamaterials: the role of Exceptional Points in
  sound absorption

abstract:
  Effective non-Hermitian Hamiltonians are obtained to describe coherent
perfect absorbing and lasing boundary conditions. PT -symmetry of the
Hamiltonians enables to design configurations which perfectly absorb at
multiple frequencies. Broadened and flat perfect absorption is predicted at the
exceptional point of PT -symmetry breaking while, for a particular case,
absorption is enhanced with the use of gain. The aforementioned phenomena are
illustrated for acoustic scattering through Helmholtz resonators revealing how
tailoring the non-Hermiticity of acoustic metamaterials leads to novel
mechanisms for enhanced absorption.


title: Monochromatic loose path partitions in k-uniform hypergraphs

abstract:
  A conjecture of Gy\'{a}rf\'{a}s and S\'{a}rk\"{o}zy says that in every
$2$-coloring of the edges of the complete $k$-uniform hypergraph $K_n^k$, there
are two disjoint monochromatic loose paths of distinct colors such that they
cover all but at most $k-2$ vertices. A weaker form of this conjecture with
$2k-5$ uncovered vertices instead of $k-2$ is proved, thus the conjecture holds
for $k=3$. The main result of this paper states that the conjecture is true for
all $k\ge 3$.


title: Faster Approximation for Maximum Independent Set on Unit Disk Graph

abstract:
  Maximum independent set from a given set $D$ of unit disks intersecting a
horizontal line can be solved in $O(n^2)$ time and $O(n^2)$ space. As a
corollary, we design a factor 2 approximation algorithm for the maximum
independent set problem on unit disk graph which takes both time and space of
$O(n^2)$. The best known factor 2 approximation algorithm for this problem runs
in $O(n^2 \log n)$ time and takes $O(n^2)$ space [Jallu and Das 2016, Das et
al. 2016].


title: Total variation denoising in $l^1$ anisotropy

abstract:
  We aim at constructing solutions to the minimizing problem for the variant of
Rudin-Osher-Fatemi denoising model with rectilinear anisotropy and to the
gradient flow of its underlying anisotropic total variation functional. We
consider a naturally defined class of functions piecewise constant on
rectangles (PCR). This class forms a strictly dense subset of the space of
functions of bounded variation with an anisotropic norm. The main result shows
that if the given noisy image is a PCR function, then solutions to both
considered problems also have this property. For PCR data the problem of
finding the solution is reduced to a finite algorithm. We discuss some
implications of this result, for instance we use it to prove that continuity is
preserved by both considered problems.


title:
Dzyaloshinsky-Moriya interaction and the ground state in S=3/2 perfect
  kagome lattice antiferromagnet $\mathbf{KCr_3(OH)_6(SO_4)_2}$ (Cr-jarosite)
  studied by X-band and high-frequency ESR

abstract:
  A single crystal S=3/2 perfect kagome lattice antiferromagnet
$\mathrm{KCr_3(OH)_6(SO_4)_2}$ (Cr-jarosite) has been studied by X-band and
high-frequency electron spin resonance (ESR). The g-values perpendicular to the
kagome plane (c-axis) and in the plane are determined to be $g_c=1.9704 \pm
0.0002$ and $g_\xi=1.9720 \pm 0.0003$, respectively, by high-frequency ESR
observed at 265 K. Antiferromagnetic resonances (AFMR) with the
antiferromagnetic gap of 120 GHz are observed at 1.9 K, which is below
$T_N$=4.5 K. The analysis of AFMR modes by the conventional molecular field
theory shows $d_p=0.27$ K and $d_z=0.07$ K, where $d_p$ and $d_z$ are in-plane
and out-of-plane components of DM d vector, respectively. From these results
and the estimated exchange interaction J=6.15 K by Okuta et al., the ground
state of Cr-jarosite is discussed in connection with the Monte Carlo
simulations result with classical Heisenberg spins on the kagome lattice by
Elhajal et al. Finally, the angular dependence of linewidth and the lineshape
observed at 296 K by X-band ESR show typical behavior of a two-dimensional
Heisenberg antiferromagnet, suggesting a good two-dimensionality of
Cr-jarosite.


title: Some criteria for regular and Gorenstein local rings via syzygy modules

abstract:
  Let $ R $ be a Cohen-Macaulay local ring. We prove that the $ n $th syzygy
module of a maximal Cohen-Macaulay $ R $-module cannot have a semidualizing
direct summand for every $ n \ge 1 $. In particular, it follows that $ R $ is
Gorenstein if and only if some syzygy of a canonical module of $ R $ has a
non-zero free direct summand. We also give a number of necessary and sufficient
conditions for a Cohen-Macaulay local ring of minimal multiplicity to be
regular or Gorenstein. These criteria are based on vanishing of certain Exts or
Tors involving syzygy modules of the residue field.


title: A Memristor Crossbar-Based Computation Scheme with High Precision

abstract:
  The memristor is promising to be the basic cell of next-generation
computation systems. Compared to the traditional MOSFET device, the memristor
is efficient over energy and area. But one of the biggest challenges faced with
researchers is how to program a memristor's resistance precisely. Recently, an
algorithm designed to save 8 valid bits in each memristor is proposed, but this
is still not sufficient for precise computation. In this paper, we propose a
crossbar-based memristor computation scheme supporting precise computations
whose operands have 32 valid bits. As a brief introduction, in a multiplication
with two operands, one operand is programmed as input signal, and the other
operand is saved into a so-called crossbar structure, which contains a group of
memristors, and each memristor saves several valid bits, usually one or two
bits only. The computation results,i.e. the multiplication of the two operands,
are contained in the outputs of the crossbar structure together with noise.
Analog-to-Digital Converters (ADCs) are then used to extract the valid bits,
which are the most significant bits of outputs. These valid bits can be
combined together with Digital-to-Analog Converters(DACs) to get the final
results. What's more, the precision of this computation scheme can be adjusted
according to the definition of the user, 32 valid bits at most, so it is
qualified for different application contexts.


title: Representations of $0$-Yokonuma-Hecke algebras

abstract:
  We give two different approaches to classifying the simple modules of
$0$-Yokonuma-Hecke algebras $Y_{r,n}(0)$ over an algebraically closed field of
characteristic $p$ such that $p$ does not divide $r.$ Using the isomorphism
between the $0$-Yokonuma-Hecke algebra and $0$-Ariki-Koike-Shoji algebra, we in
fact give another way to obtain the simple modules of the latter, which was
previously studied by Hivert, Novelli and Thibon (Adv. Math. $\bf{205}$ (2006)
504-548). In the appendix, we give the classification of simple modules of the
nil Yokonuma-Hecke algebra.


title: Does the Gogny interaction need a third Gaussian?

abstract:
  By considering infinite matter constraints only, we suggest in this paper
that the Gogny interaction should benefit from a third Gaussian in its central
part. A statistical analysis is given to select the possible ranges which are
compatible with these constraints and which minimize a $\chi^2$ function.


title:
Finite Satisfiability of the Two-Variable Guarded Fragment with
  Transitive Guards and Related Variants

abstract:
  We consider extensions of the two-variable guarded fragment, GF2, where
distinguished binary predicates that occur only in guards are required to be
interpreted in a special way (as transitive relations, equivalence relations,
pre-orders or partial orders). We prove that the only fragment that retains the
finite (exponential) model property is GF2 with equivalence guards without
equality. For remaining fragments we show that the size of a minimal finite
model is at most doubly exponential. To obtain the result we invent a strategy
of building finite models that are formed from a number of multidimensional
grids placed over a cylindrical surface. The construction yields a
2NExpTime-upper bound on the complexity of the finite satisfiability problem
for these fragments. We improve the bounds and obtain optimal ones for all the
fragments considered, in particular NExpTime for GF2 with equivalence guards,
and 2ExpTime for GF2 with transitive guards. To obtain our results we
essentially use some results from integer programming.


title:
Error concealment by means of motion refinement and regularized Bregman
  divergence

abstract:
  This work addresses the problem of error concealment in video transmission
systems over noisy channels employing Bregman divergences along with
regularization. Error concealment intends to improve the effects of
disturbances at the reception due to bit-errors or cell loss in packet
networks. Bregman regularization gives accurate answers after just some
iterations with fast convergence, better accuracy, and stability. This
technique has an adaptive nature: the regularization functional is updated
according to Bregman functions that change from iteration to iteration
according to the nature of the neighborhood under study at iteration n.
Numerical experiments show that high-quality regularization parameter estimates
can be obtained. The convergence is sped up while turning the regularization
parameter estimation less empiric, and more automatic.


title: Instabilities in granular gas-solid flows

abstract:
  A linear stability analysis of the hydrodynamic equations with respect to the
homogeneous cooling state is performed to study the conditions for stability of
a suspension of solid particles immersed in a viscous gas. The dissipation in
such systems arises from two different sources: inelasticity in particle
collisions and viscous friction dissipation due to the influence of gas phase
on solid particles. The starting point is a suspension model based on the
(inelastic) Enskog kinetic equation where the effect of the interstitial gas
phase on the dynamics of grains is modeled via a viscous drag force. The study
is carried out in two different steps. First, the transport coefficients of the
system are obtained by solving the Enskog equation by means of the
Chapman-Enskog method up to first order in spatial gradients. Once the
transport properties are known, then the corresponding linearized hydrodynamic
equations are solved to get the dispersion relations. In contrast to previous
studies [V. Garz\'o \emph{et al.}, Phys. Rev. E \textbf{93}, 012905 (2016)],
the hydrodynamic modes are \emph{analytically} obtained as functions of the
parameter space of the system. As expected, linear stability shows $d-1$
transversal (shear) modes (where $d$ is the dimensionality of the system) and a
longitudinal "heat" mode to be unstable with respect to long enough wavelength
excitations. The results also show that the main effect of gas phase is to
decrease the value of the critical length $L_c$ (beyond which the system
becomes unstable) with respect to its value for a dry granular fluid.
Comparison with direct numerical simulations for $L_c$ shows a good agreement
for conditions of practical interest.


title: Detecting Moving Regions in CrowdCam Images

abstract:
  We address the novel problem of detecting dynamic regions in CrowdCam images,
a set of still images captured by a group of people. These regions capture the
most interesting parts of the scene, and detecting them plays an important role
in the analysis of visual data. Our method is based on the observation that
matching static points must satisfy the epipolar geometry constraints, but
computing exact matches is challenging. Instead, we compute the probability
that a pixel has a match, not necessarily the correct one, along the
corresponding epipolar line. The complement of this probability is not
necessarily the probability of a dynamic point because of occlusions, noise,
and matching errors. Therefore, information from all pairs of images is
aggregated to obtain a high quality dynamic probability map, per image.
Experiments on challenging datasets demonstrate the effectiveness of the
algorithm on a broad range of settings; no prior knowledge about the scene, the
camera characteristics or the camera locations is required.


title: Constrained Sparse Galerkin Regression

abstract:
  Although major advances have been achieved over the past decades for the
reduction and identification of linear systems, deriving nonlinear low-order
models still is a chal- lenging task. In this work, we develop a new
data-driven framework to identify nonlinear reduced-order models of a fluid by
combining dimensionality reductions techniques (e.g. proper orthogonal
decomposition) and sparse regression techniques from machine learn- ing. In
particular, we extend the sparse identification of nonlinear dynamics (SINDy)
algorithm to enforce physical constraints in the regression, namely
energy-preserving quadratic nonlinearities. The resulting models, hereafter
referred to as Galerkin regression models, incorporate many beneficial aspects
of Galerkin projection, but without the need for a full-order or high-fidelity
solver to project the Navier-Stokes equations. Instead, the most parsimonious
nonlinear model is determined that is consistent with observed mea- surement
data and satisfies necessary constraints. Galerkin regression models also
readily generalize to include higher-order nonlinear terms that model the
effect of truncated modes. The effectiveness of Galerkin regression is
demonstrated on two different flow configurations: the two-dimensional flow
past a circular cylinder and the shear-driven cavity flow. For both cases, the
accuracy of the identified models compare favorably against reduced-order
models obtained from a standard Galerkin projection procedure. Present results
highlight the importance of cubic nonlinearities in the construction of
accurate nonlinear low-dimensional approximations of the flow systems,
something which cannot be readily obtained using a standard Galerkin projection
of the Navier-Stokes equations. Finally, the entire code base for our
constrained sparse Galerkin regression algorithm is freely available online.


title:
On global attractors and radiation damping for nonrelativistic particle
  coupled to scalar field

abstract:
  We consider the Hamiltonian system of scalar wave field and a single
nonrelativistic particle coupled in a translation invariant manner. The
particle is also subject to a confining external potential. The stationary
solutions of the system are a Coulomb type wave field centered at those
particle positions for which the external force vanishes. We prove that
solutions of finite energy converge, in suitable local energy seminorms, to the
set ${\cal S}$ of all stationary states in the long time limit $t\to\pm\infty$.
Further we show that the rate of relaxation to a stable stationary state is
determined by spatial decay of initial data. The convergence is followed by the
radiation of the dispersion wave which is a solution to the free wave equation.
  Similar relaxation has been proved previously for the case of relativistic
particle when the speed of the particle is less than the speed of light. Now we
extend these results to nonrelativistic particle with arbitrary superlight
velocity. However, we restrict ourselves by the plane particle trajectories.
The extension to general case remains an open problem.


title: Solutions of Grinberg equation and removable cycles in a cycle basis

abstract:
  Let G (V, E) be a simple graph with vertex set V and edge set E. A
generalized cycle is a subgraph such that any vertex degree is even. A simple
cycle (briefly in a cycle) is a connected subgraph such that every vertex has
degree 2. A basis of the cycle space is called a cycle basis of G (V, E). A
cycle basis where the sum of the weights of the cycles is minimal is called a
minimum cycle basis of G. Grinberg theorem is a necessary condition to have a
Hamilton cycle in planar graphs. In this paper, we use the cycles of a cycle
basis to replace the faces and obtain an equality of inner faces in Grinberg
theorem, called Grinberg equation. We explain why Grinberg theorem can only be
a necessary condition of Hamilton graphs and apply the theorem, to be a
necessary and sufficient condition, to simple graphs.


title: Constructions and bounds for separating hash families

abstract:
  In this paper, we present a new construction for strong separating hash
families by using hypergraphs and obtain some optimal separating hash families.
  We also improve some previously known bounds of separating hash families.


title: Neutrino Monte-Carlo Event Generators and Cross-section Data

abstract:
  In recent years a number of new theoretical models have been implemented into
Monte-Carlo neutrino interaction event generators. Being able to compare
multiple model predictions is invaluable to the field, especially as it is
unfortunately still unclear which one provides the best fit to the entire
collection of neutrino cross-section data. Using a recently developed neutrino
generator tuning framework (NUISANCE), we review a selection of models in the
NEUT and NuWro generators through comparisons to existing bubble chamber,
MINERvA, and MiniBooNE cross-section data.


title:
Pressure-induced quantum phase transition in the itinerant ferromagnet
  UCoGa

abstract:
  In this paper, we report the results of a high pressure study of the
itinerant 5f-electron ferromagnet UCoGa. The work is focused on probing the
expected ferromagnet-to-paramagnet quantum phase transition induced by high
pressure and on the general features of the P-T(-H) phase diagram. Diamond
anvil cells were employed to measure the magnetization and electrical
resistivity under pressures up to ~ 10 GPa.At ambient pressure, UCoGa exhibits
collinear ferromagnetic ordering of uranium magnetic moments {\mu}U ~ 0.74
{\mu}B (at 2 K) aligned along the c-axis of the hexagonal crystal structure
below Curie temperature TC = 48K. With the application of pressure, gradual
decrease of both, TC and the saturated magnetic moment, has been observed up to
pressures ~ 6 GPa. This is followed by a sharp drop of magnetic moment and a
sudden disappearance of the magnetic order at the pressure of 6.5 GPa,
suggesting a first-order phase transition, as expected for a clean system. The
low temperature power law dependence of the electrical resistivity shows
distinct anomalies around the ~ 6 GPa, consistent with the pressure evolution
of the magnetic moment and the ordering temperature. The tricritical point of
the UCoGa phase diagram is located at approximately ~ 30 K and ~ 6 GPa.


title: Machine-learning based interatomic potential for amorphous carbon

abstract:
  We introduce a Gaussian approximation potential (GAP) for atomistic
simulations of liquid and amorphous elemental carbon. Based on a
machine-learning representation of the density-functional theory (DFT)
potential-energy surface, such interatomic potentials enable materials
simulations with close-to DFT accuracy but at much lower computational cost. We
first determine the maximum accuracy that any finite-range potential can
achieve in carbon structures; then, using a novel hierarchical set of two-,
three-, and many-body structural descriptors, we construct a GAP model that can
indeed reach the target accuracy. The potential yields accurate energetic and
structural properties over a wide range of densities; it also correctly
captures the structure of the liquid phases, at variance with state-of-the-art
empirical potentials. Exemplary applications of the GAP model to surfaces of
"diamond-like" tetrahedral amorphous carbon (ta-C) are presented, including an
estimate of the amorphous material's surface energy, and simulations of
high-temperature surface reconstructions ("graphitization"). The new
interatomic potential appears to be promising for realistic and accurate
simulations of nanoscale amorphous carbon structures.


title: NEUT/NuWro cross-section modelling at low three-momentum transfer

abstract:
  The MINERvA collaboration has reported a Charged-Current inclusive (CCinc)
cross-section measurement on a CH target. This was performed by looking at both
the muon and hadronic final state particles to create a double differential
cross-section distribution that provides additional insight into the different
regions of the phase-space where nuclear effects are present. We show early
comparisons of the NEUT and NuWro generators in an attempt to estimate which
parts of the models are in agreement with this data.


title: Tracing metaphors in time through self-distance in vector spaces

abstract:
  From a diachronic corpus of Italian, we build consecutive vector spaces in
time and use them to compare a term's cosine similarity to itself in different
time spans. We assume that a drop in similarity might be related to the
emergence of a metaphorical sense at a given time. Similarity-based
observations are matched to the actual year when a figurative meaning was
documented in a reference dictionary and through manual inspection of corpus
occurrences.


title:
Rigidity of Ext and Tor with coefficients in residue fields of a
  commutative noetherian ring

abstract:
  Let p be a prime ideal in a commutative noetherian ring R. It is proved that
if an R-module M satisfies Tor^R_n(k(p),M) = 0 for some n \geq dim R_p, where
k(p) is the residue field at p, then Tor^R_i(k(p),M) = 0 holds for all i \geq
n. Similar rigidity results concerning Ext_R^*(k(p),M) are proved, and
applications to the theory of homological dimensions are explored.


title:
Enhanced magnetocaloric effect in a proximity of magnetization steps and
  jumps of spin-1/2 XXZ Heisenberg regular polyhedra

abstract:
  The magnetization process and adiabatic demagnetization of the
antiferromagnetic spin-1/2 XXZ Heisenberg clusters with the shape of regular
polyhedra (tetrahedron, octahedron, cube, icosahedron and dodecahedron) are
examined using the exact diagonalization method. It is demonstrated that a
quantum (xy) part of the XXZ exchange interaction is a primary cause for
presence of additional intermediate magnetization plateaux and steps, which are
totally absent in the limiting Ising case. The only exception to this rule is
the spin-1/2 XXZ Heisenberg tetrahedron, which shows just a quantitative shift
of the level-crossing fields related to two magnetization steps. It is
evidenced that the spin-1/2 XXZ Heisenberg regular polyhedra exhibit an
enhanced magnetocaloric effect in a proximity of the magnetization steps and
jumps, which are accompanied with a rapid drop (rise) of temperature just above
(below) of the level-crossing field when the magnetic field is removed
adiabatically.


title: A LOFAR detection of the low mass young star T Tau at 149 MHz

abstract:
  Radio observations of young stellar objects (YSOs) enable the study of
ionised plasma outflows from young protostars via their free-free radiation.
Previous studies of the low-mass young system T Tau have used radio
observations to model the spectrum and estimate important physical properties
of the associated ionised plasma (local electron density, ionised gas content
and emission measure). However, without an indication of the low-frequency
turnover in the free-free spectrum, these properties remain difficult to
constrain. This paper presents the detection of T Tau at 149 MHz with the Low
Frequency Array (LOFAR) - the first time a YSO has been observed at such low
frequencies. The recovered total flux indicates that the free-free spectrum may
be turning over near 149 MHz. The spectral energy distribution is fitted and
yields improved constraints on local electron density ($(7.2 \pm
2.1)\times10^{3}$ cm$^{-3}$), ionised gas mass ($(1.0 \pm 1.8)\times10^{-6}$
M$_{\odot}$) and emission measure ($(1.67 \pm 0.14)\times10^5$ pc cm$^{-6}$).


title:
Three-dimensional hydrodynamical CO5BOLD model atmospheres of red giant
  stars. V. Oxygen abundance in the metal-poor giant HD 122563 from OH UV lines

abstract:
  Although oxygen is an important tracer of the early Galactic evolution, its
abundance trends with metallicity are still relatively poorly known at [Fe/H] <
-2.5. This is in part due to a lack of reliable oxygen abundance indicators in
the metal-poor stars, in part due to shortcomings in 1D LTE abundance analyses.
In this study we determined the oxygen abundance in the metal-poor halo giant
HD 122563 using a 3D hydrodynamical CO5BOLD model atmosphere. Our main goal was
to understand whether a 3D LTE analysis may help to improve the reliability of
oxygen abundances determined from OH UV lines in comparison to those obtained
using standard 1D LTE methodology. The oxygen abundance in HD 122563 was
determined using 71 OH UV lines located in the wavelength range between 308-330
nm. The analysis was done using a high-resolution VLT UVES spectrum with a 1D
LTE spectral line synthesis performed using the SYNTHE package and classical
ATLAS9 model atmosphere. Subsequently, a 3D hydrodynamical CO5BOLD, and 1D
hydrostatic LHD model atmospheres were used in order to compute 3D-1D abundance
corrections. For this, the microturbulence velocity used with the 1D LHD model
atmosphere was derived from the hydrodynamical CO5BOLD model atmosphere. As in
previous studies, we found trends of the 1D LTE oxygen abundances determined
from OH UV lines with line parameters, such as the line excitation potential
and the line strength. These trends become significantly less pronounced in 3D
LTE. Using OH UV lines we determined a 3D LTE oxygen abundance in HD 122563 of
A(O) = 6.23 +/- 0.13. This is in fair agreement with the oxygen abundance
obtained from OH IR lines, A(O) = 6.39 +/- 0.11, but it is noticeably lower
than that determined using the forbidden [OI] line, A(O) = 6.53 +/- 0.15. While
the exact cause for this discrepancy remains unclear, it is very likely that
non-LTE effects may play a decisive role here.


title: Deconfinement, chiral transition and localisation in a QCD-like model

abstract:
  We study the problems of deconfinement, chiral symmetry restoration and
localisation of the low Dirac eigenmodes in a toy model of QCD, namely
unimproved staggered fermions on lattices of temporal extension $N_T=4$. This
model displays a genuine deconfining and chirally-restoring first-order phase
transition at some critical value of the gauge coupling. Our results indicate
that the onset of localisation of the lowest Dirac eigenmodes takes place at
the same critical coupling where the system undergoes the first-order phase
transition. This provides further evidence of the close relation between
deconfinement, chiral symmetry restoration and localisation of the low modes of
the Dirac operator on the lattice.


title: The BRITE spectropolarimetric program

abstract:
  A high-resolution spectropolarimetric survey of all (573) stars brighter than
magnitude V=4 has been undertaken with Narval at TBL, ESPaDOnS at CFHT, and
HarpsPol at ESO, as a ground-based support to the BRITE constellation of
nano-satellites in the framework of the Ground-Based Observation Team (GBOT).
The goal is to detect magnetic fields in BRITE targets, as well as to provide
one very high-quality, high-resolution spectrum for each star. The survey is
nearly completed and already led to the discovery of 42 new magnetic stars and
the confirmation of several other magnetic detections, including field
discoveries in, e.g., an Am star, two {\delta} Scuti stars, hot evolved stars,
and stars in clusters. Follow-up spectropolarimetric observations of
approximately a dozen of these magnetic stars have already been performed to
characterise their magnetic field configuration and strength in detail.


title:
Galton-Watson processes in varying environment and accessibility
  percolation

abstract:
  This paper deals with branching processes in varying environment, namely,
whose offspring distributions depend on the generations. We provide sufficient
conditions for survival or extinction which rely only on the first and second
moments of the offspring distributions. These results are then applied to
branching processes in varying environment with selection where every particle
has a real-valued label and labels can only increase along genealogical
lineages; we obtain analogous conditions for survival or extinction. These last
results can be interpreted in terms of accessibility percolation on
Galton-Watson trees, which represents a relevant tool for modeling the
evolution of biological populations.


title:
A frustrated honeycomb-bilayer Heisenberg antiferromagnet: The
  spin-$\frac{1}{2}$ $J_{1}$--$J_{2}$--$J_{1}^{\perp}$ model

abstract:
  We use the coupled cluster method to study the zero-temperature quantum phase
diagram of the spin-$\frac{1}{2}$ $J_{1}$--$J_{2}$--$J_{1}^{\perp}$ model on
the honeycomb bilayer lattice. In each layer we include both nearest-neighbor
and frustrating next-nearest-neighbor antiferromagnetic exchange couplings, of
strength $J_{1}>0$ and $J_{2} \equiv \kappa J_{1} > 0$, respectively. The two
layers are coupled by an interlayer nearest-neighbor exchange, with coupling
constant $J_{1}^{\perp} \equiv \delta J_{1}>0$. We calculate directly in the
infinite-lattice limit both the ground-state energy per spin and the N\'{e}el
magnetic order parameter, as well as the triplet spin gap. By implementing the
method to very high orders of approximation we obtain an accurate estimate for
the full boundary of the N\'{e}el phase in the $\kappa\delta$ plane. For each
value $\delta < \delta_{c}^{>}(0) \approx 1.70(5)$ we find an upper critical
value $\kappa_{c}(\delta)$, such that N\'{e}el order is present for $\kappa <
\kappa_{c}(\delta)$. Conversely, for each value $\kappa < \kappa_{c}(0) \approx
0.19(1)$ we find an upper critical value $\delta_{c}^{>}(\kappa)$, such that
N\'{e}el order persists for $0 < \delta < \delta_{c}^{>}(\kappa)$. Most
interestingly, for values of $\kappa$ in the range $\kappa_{c}(0) < \kappa <
\kappa^{>} \approx 0.215(2)$ we find a reentrant behavior such that N\'{e}el
order exists only in the range $\delta_{c}^{<}(\kappa) < \delta <
\delta_{c}^{>}(\kappa)$, with $\delta_{c}^{<}(\kappa)>0$. These latter upper
and lower critical values coalesce when $\kappa = \kappa^{>}$, such that
$\delta_{c}^{<}(\kappa^{>}) = \delta_{c}^{>}(\kappa^{>}) \approx 0.25(5)$.


title:
Experimental signatures of an absorbing-state phase transition in an
  open driven many-body quantum system

abstract:
  Understanding and probing phase transitions in non-equilibrium systems is an
ongoing challenge in physics. A particular instance are phase transitions that
occur between a non-fluctuating absorbing phase, e.g., an extinct population,
and one in which the relevant order parameter, such as the population density,
assumes a finite value. Here we report the observation of signatures of such a
non-equilibrium phase transition in an open driven quantum system. In our
experiment rubidium atoms in a quasi one-dimensional cold disordered gas are
laser-excited to Rydberg states under so-called facilitation conditions. This
conditional excitation process competes with spontaneous decay and leads to a
crossover between a stationary state with no excitations and one with a finite
number of excitations. We relate the underlying physics to that of an absorbing
state phase transition in the presence of a field (i.e. off-resonant excitation
processes) which slightly offsets the system from criticality. We observe a
characteristic power-law scaling of the Rydberg excitation density as well as
increased fluctuations close to the transition point. Furthermore, we argue
that the observed transition relies on the presence of atomic motion which
introduces annealed disorder into the system and enables the formation of
long-ranged correlations. Our study paves the road for future investigations
into the largely unexplored physics of non-equilibrium phase transitions in
open many-body quantum systems.


title:
Solar Energetic Particle Events with Protons above 500 MeV between 1995
  and 2015 Measured with SOHO/EPHIN

abstract:
  The Sun is an effective particle accelerator producing solar energetic
particle (SEP) events during which particles up to several GeVs can be
observed. Those events observed at Earth with the neutron monitor network are
called ground level enhancements (GLEs). Although these events with a high
energy component have been investigated for several decades, a clear relation
between the spectral shape of the SEPs outside the Earth's magnetosphere and
the increase in neutron monitor count rate has yet to be established. Hence, an
analysis of these events is of interest for the space weather as well as the
solar event community. In this work, SEP events with protons accelerated to
above 500 MeV have been identified using data from the Electron Proton Helium
Instrument (EPHIN) aboard the Solar and Heliospheric Observatory (SOHO) between
1995 and 2015. For a statistical analysis, onset times have been determined for
the events and the proton energy spectra were derived and fitted with a power
law. As a result, a list of 42 SEP events with protons accelerated to above 500
MeV measured with the EPHIN instrument onboard SOHO is presented. The
statistical analysis based on the fitted spectral slopes and absolute
intensities is discussed with special emphasis on whether or not an event has
been observed as GLE. Furthermore, a correlation between the derived intensity
at 500 MeV and the observed increase in neutron monitor count rate has been
found for a subset of events.


title: Irradiated stars with convective envelopes

abstract:
  The observed radii of M dwarfs in eclipsing binaries exceed predicted radii
by ~ 5%. To investigate this anomaly, the structure of low-mass stars
irradiated by a close companion is considered. Irradiation modifies the surface
boundary conditions and thereby also the adiabatic constants of their outer
convection zones. This changes the models' radii and luminosities. For
short-period M dwarf binaries with components of similar mass, radius inflation
due to their mutual irradiation is found to be < 0.4%. This is an order of
magnitude too small to explain the observed anomaly. Although stronger
irradiation results in a monotonically increasing radius, a saturation effect
limits the inflation to <~ 5\%.


title:
Theory of transport property of density wave phases in three-dimensional
  metals and semimetals under high magnetic field

abstract:
  Three-dimensional (3D) metals/semimetals under magnetic field have an
instability toward a density wave (DW) ordering which breaks a translational
symmetry along the field direction. Effective boson models for the DW phases
take forms of XY models with/without Potts terms. Longitudinal conductivity
along the field direction is calculated in the DW phases with inclusion of
effects of low-energy charge fluctuation (phason) and disorder. A
single-particle imaginary-time Green function is identified with a partition
function of 3D XY models in the presence of pairs of magnetic monopoles. In
terms of the celebrated electromagnetic duality, electronic spectral function
is calculated near the DW phase transition. The result shows that the
single-particle spectral function acquires an additional low-energy feature due
to the strong phason fluctuation. Relevance to an in-plane conductance due to
surface chiral Fermi arc states are also discussed.


title: The MacLane class and the Eremenko-Lyubich class

abstract:
  In 1970 G. R. MacLane asked if it is possible for a locally univalent
function in the class $\mathcal{A}$ to have an arc tract. This question remains
open, but several results about it have been given. We significantly strengthen
these results, in particular replacing the condition of local univalence by the
more general condition that the set of critical values is bounded. Also, we
adapt a recent powerful technique of C. J. Bishop in order to show that there
is a function in the Eremenko-Lyubich class for the disc that is not in the
class $\mathcal{A}$.


title:
Experimental Adiabatic Quantum Factorization under Ambient Conditions
  Based on a Solid-State Single Spin System

abstract:
  The adiabatic quantum computation is a universal and robust method of quantum
computing. In this architecture, the problem can be solved by adiabatically
evolving the quantum processor from the ground state of a simple initial
Hamiltonian to that of a final one, which encodes the solution of the problem.
By far, there is no experimental realization of adiabatic quantum computation
on a single solid spin system under ambient conditions, which has been proved
to be a compatible candidate for scalable quantum computation. In this letter,
we report on the first experimental realization of an adiabatic quantum
algorithm on a single solid spin system under ambient conditions. All elements
of adiabatic quantum computation, including initial state preparation,
adiabatic evolution, and final state readout, are realized experimentally. As
an example, we factored 35 into its prime factors 5 and 7 on our adiabatic
quantum processor.


title: Higher order corrections for anisotropic bootstrap percolation

abstract:
  We study the critical probability for the metastable phase transition of the
two-dimensional anisotropic bootstrap percolation model with
$(1,2)$-neighbourhood and threshold $r = 3$. The first order asymptotics for
the critical probability were recently determined by the first and second
authors. Here we determine the following sharp second and third order
asymptotics: \[
  p_c\big( [L]^2,\mathcal{N}_{(1,2)},3 \big) \; = \; \frac{(\log \log
L)^2}{12\log L} \, - \, \frac{\log \log L \, \log \log \log L}{ 3\log L}
  + \frac{\left(\log \frac{9}{2} + 1 \pm o(1) \right)\log \log L}{6\log L}. \]
We note that the second and third order terms are so large that the first order
asymptotics fail to approximate $p_c$ even for lattices of size well beyond
$10^{10^{1000}}$.


title: Effects of additive noise on the stability of glacial cycles

abstract:
  It is well acknowledged that the sequence of glacial-interglacial cycles is
paced by the astronomical forcing. However, how much is the sequence robust
against natural fluctuations associated, for example, with the chaotic motions
of atmosphere and oceans? In this article, the stability of the
glacial-interglacial cycles is investigated on the basis of simple conceptual
models. Specifically, we study the influence of additive white Gaussian noise
on the sequence of the glacial cycles generated by stochastic versions of
several low-order dynamical system models proposed in the literature. In the
original deterministic case, the models exhibit different types of attractors:
a quasiperiodic attractor, a piecewise continuous attractor, strange nonchaotic
attractors, and a chaotic attractor. We show that the combination of the
quasiperiodic astronomical forcing and additive fluctuations induce a form of
temporarily quantised instability. More precisely, climate trajectories
corresponding to different noise realizations generally cluster around a small
number of stable or transiently stable trajectories present in the
deterministic system. Furthermore, these stochastic trajectories may show
sensitive dependence on very small amounts of perturbations at key times.
Consistently with the complexity of each attractor, the number of trajectories
leaking from the clusters may range from almost zero (the model with a
quasiperiodic attractor) to a significant fraction of the total (the model with
a chaotic attractor), the models with strange nonchaotic attractors being
intermediate. Finally, we discuss the implications of this investigation for
research programmes based on numerical simulators. }


title:
Ground state solutions for a fractional Schr\"odinger equation with
  critical growth

abstract:
  In this paper we investigate the existence of nontrivial ground state
solutions for the following fractional scalar field equation \begin{align*}
(-\Delta)^{s} u+V(x)u= f(u) \mbox{ in } \mathbb{R}^{N}, \end{align*} where
$s\in (0,1)$, $N> 2s$, $(-\Delta)^{s}$ is the fractional Laplacian, $V:
\mathbb{R}^{N}\rightarrow \mathbb{R}$ is a bounded potential satisfying
suitable assumptions, and $f\in C^{1, \beta}(\mathbb{R}, \mathbb{R})$ has
critical growth. We first analyze the case $V$ constant, and then we develop a
Jeanjean-Tanaka argument \cite{JT} to deal with the non autonomous case. As far
as we know, all results presented here are new.


title:
Conformal Complex Scalar Singlet Extensions of the Standard Model:
  Symmetry Breaking Patterns and Phenomenology

abstract:
  We consider a conformal complex singlet extension of the Standard Model with
a Higgs portal interaction. Two different scenarios depending on whether the
global U(1) symmetry is broken or not have been studied. In the unbroken phase,
the decay of the complex singlet is protected by the global U(1) symmetry which
leads to an ideal cold dark matter candidate. In the broken phase, we are able
to provide a second Higgs at $554\,\rm{GeV}$. In addition, gauging the global
U(1) symmetry, we can construct an asymptotically safe U(1)' leptophobic model.
We combine the notion of asymptotic safety with conformal symmetry and use the
renormalization group equations as a bridge to connect UV boundary conditions
and Electroweak/ TeV scale physics. We also provide a detailed example to show
that these boundary conditions will lead to phenomenological signatures such as
diboson excesses which could be tested at the LHC.


title:
Role of Temporal Diversity in Inferring Social Ties Based on
  Spatio-Temporal Data

abstract:
  The last two decades have seen a tremendous surge in research on social
networks and their implications. The studies includes inferring social
relationships, which in turn have been used for target advertising,
recommendations, search customization etc. However, the offline experiences of
human, the conversations with people and face-to-face interactions that govern
our lives interactions have received lesser attention. We introduce DAIICT
Spatio-Temporal Network (DSSN), a spatiotemporal dataset of 0.7 million data
points of continuous location data logged at an interval of every 2 minutes by
mobile phones of 46 subjects. Our research is focused at inferring relationship
strength between students based on the spatiotemporal data and comparing the
results with the self-reported data. In that pursuit we introduce Temporal
Diversity, which we show to be superior in its contribution to predicting
relationship strength than its counterparts. We also explore the evolving
nature of Temporal Diversity with time. Our rich dataset opens various other
avenues of research that require fine-grained location data with bounded
movement of participants within a limited geographical area. The advantage of
having a bounded geographical area such as a university campus is that it
provides us with a microcosm of the real world, where each such geographic zone
has an internal context and function and a high percentage of mobility is
governed by schedules and time-tables. The bounded geographical region in
addition to the age homogeneous population gives us a minute look into the
active internal socialization of students in a university.


title: Static axisymmetric rings in general relativity: How diverse they are

abstract:
  Three static and axially symmetric (Weyl-type) ring singularities -- the
Majumdar-Papapetrou--type (extremally charged) ring, the Bach-Weyl ring and the
Appell ring -- are studied in general relativity in order to show how
remarkably the geometries in their vicinity differ from each other. This is
demonstrated on basic measures of the rings and on invariant characteristics
given by the metric and by its first and second derivatives (lapse,
gravitational acceleration and curvature), and also on geodesic motion. The
results are also compared against the Kerr space-time which possesses a ring
singularity too. The Kerr solution is only stationary, not static, but in spite
of the consequent complication by dragging, its ring appears to be simpler than
the static rings. We show that this mainly applies to the Bach-Weyl ring,
although this straightforward counter-part of the Newtonian homogeneous
circular ring is by default being taken as the simplest ring solution, and
although the other two static ring sources may seem more "artificial". The
weird, directional deformation around the Bach-Weyl ring probably indicates
that a more adequate coordinate representation and interpretation of this
source should exists.


title: X, Y and Z States

abstract:
  Many new states in the charmonium mass region were recently discovered by
BaBar, Belle, CLEO-c, CDF, D0, BESIII, LHCb and CMS Collaborations. We use the
QCD Sum Rule approach to study the possible structure of some of these states.


title:
A partial order principle and vector variational principle for
  $\epsilon$-efficient solutions in the sense of N\'{e}meth

abstract:
  In this paper, we establish a partial order principle, which is useful to
deriving vector Ekeland variational principle (denoted by EVP). By using the
partial order principle and extending Gerstewitz's functions, we obtain a
vector EVP for $\epsilon$-efficient solutions in the sense of N\'{e}meth, which
essentially improves the earlier results by removing a usual assumption for
boundedness of range of the objective function. From this, we also deduce
several special vector EVPs, which improve and generalize the related known
results.


title:
The number of subgroups of the group $\Bbb{Z}_m\times \Bbb{Z}_n \times
  \Bbb{Z}_r \times \Bbb{Z}_s$

abstract:
  We deduce direct formulas for the total number of subgroups and the number of
subgroups of a given order of the group $\Bbb{Z}_m\times \Bbb{Z}_n \times
\Bbb{Z}_r \times \Bbb{Z}_s$, where $m,n,r,s\in \Bbb{N}$. The proofs are by some
simple group theoretical and number theoretical arguments based on Goursat's
lemma for groups. Two conjectures are also formulated.


title:
Anharmonic quantum mechanical systems do not feature phase space
  trajectories

abstract:
  Phase space dynamics in classical mechanics is described by transport along
trajectories. Anharmonic quantum mechanical systems do not allow for a
trajectory-based description of their phase space dynamics. This invalidates
some approaches to quantum phase space studies. We first demonstrate the
absenceof trajectories in general terms. We then give an explicit proof for all
quantum phase space distributions with negative values: we show that the
generation of coherences in anharmonic quantum mechanical systems is
responsible for the occurrence of singularities in their phase space velocity
fields, and vice versa. This explains numerical problems repeatedly reported in
the literature, and provides deeper insight into the nature of quantum phase
space dynamics.


title: Measuring Topological Number of a Chern-Insulator from Quench Dynamics

abstract:
  In this letter we show how the topological number of a static Hamiltonian can
be measured from a dynamical quench process. We focus on a two-band Chern
insulator in two-dimension, for instance, the Haldane model, whose dynamical
process can be described by a mapping from the $[k_x,k_y,t]$ space to the Bloch
sphere, characterized by the Hopf invariant. Such a mapping has been
constructed experimentally by measurements in cold atom systems. We show that,
taking any two constant vectors on the Bloch sphere, their inverse images of
this mapping are two trajectories in the $[k_x,k_y,t]$ space, and the linking
number of these two trajectories exactly equals to the Chern number of the
static Hamiltonian. Applying this result to a recent experiment from the
Hamburg group, we show that the linking number of the trajectories of the phase
vortices determines the phase boundary of the static Hamiltonian.


title: Getting Started with Neural Models for Semantic Matching in Web Search

abstract:
  The vocabulary mismatch problem is a long-standing problem in information
retrieval. Semantic matching holds the promise of solving the problem. Recent
advances in language technology have given rise to unsupervised neural models
for learning representations of words as well as bigger textual units. Such
representations enable powerful semantic matching methods. This survey is meant
as an introduction to the use of neural models for semantic matching. To remain
focused we limit ourselves to web search. We detail the required background and
terminology, a taxonomy grouping the rapidly growing body of work in the area,
and then survey work on neural models for semantic matching in the context of
three tasks: query suggestion, ad retrieval, and document retrieval. We include
a section on resources and best practices that we believe will help readers who
are new to the area. We conclude with an assessment of the state-of-the-art and
suggestions for future work.


title:
Do Water Fountain Jets Really Indicate the Onset of the Morphological
  Metamorphosis of Circumstellar Envelopes?

abstract:
  The small-scale bipolar jets having short dynamical ages from "water fountain
(WF)" sources are regarded as an indication of the onset of circumstellar
envelope morphological metamorphosis of intermediate-mass stars. Such process
usually happens at the end of the asymptotic giant branch (AGB) phase. However,
recent studies found that WFs could be AGB stars or even early planetary
nebulae. This fact prompted the idea that WFs may not necessarily be objects at
the beginning of the morphological transition process. In the present work, we
show that WFs could have different envelope morphologies by studying their
spectral energy distribution profiles. Some WFs have spherical envelopes that
resembles usual AGB stars, while others have aspherical envelopes which are
more common to post-AGB stars. The results imply that WFs may not represent the
earliest stage of the morphological metamorphosis. We further argue that the
dynamical age of a WF jet, which can be calculated from maser proper motions,
may not be the real age of the jet. The dynamical age cannot be used to justify
the moment when the envelope begins to become aspherical, nor to tell the
concrete evolutionary status of the object. A WF jet could be the innermost
part of a larger well-developed jet, which is not necessarily a young jet.


title:
Optimization Models for Flexible and Adaptive SDN Network Virtualization
  Layers

abstract:
  Network hypervisors provide the network virtualization layer for Software
Defined Networking (SDN). They enable virtual network (VN) tenants to bring
their SDN controllers to program their logical networks individually according
to their demands. In order to make use of the high flexibility of virtual SDN
networks and to provide high performance, the deployment of the virtualization
layer needs to adapt to changing VN demands. This paper initializes the study
of the optimization of dynamic SDN network virtualization layers. Based on the
definition of reconfiguration events, we formalized mixed integer programs to
analyze the multi-objective problem of adapting virtualization layers. Our
initial simulation results demonstrate Pareto frontiers of conflicting
objectives, namely control plane latency and hypervisor and control path
reconfigurations.


title: Search for a high mass diphoton resonance using the ATLAS detector

abstract:
  A search for new spin-0 resonances decaying into two photons in the ATLAS
experiment at the LHC is described. The analysis is based on $pp$ collision
data at $\sqrt{s}$=13 TeV corresponding to integrated luminosities of 3.2/fb
and 12.2/fb recorded in 2015 and 2016, respectively. A deviation from the
Standard Model background-only hypothesis corresponding to 3.4 standard
deviations is observed in the 2015 data for a resonance mass hypothesis of 730
GeV. No significant excess at such mass over the background expectation is
observed in the 2016 data. Limits on the production cross section times
branching ratio to two photons of such resonances are reported.


title:
Estimation of clusterwise linear regression models with a shrinkage-like
  approach

abstract:
  Constrained approaches to maximum likelihood estimation in the context of
finite mixtures of normals have been presented in the literature. A fully
data-dependent constrained method for maximum likelihood estimation of
clusterwise linear regression is proposed, which extends previous work in
equivariant data-driven estimation of finite mixtures of Gaussians for
classification. The method imposes plausible bounds on the component variances,
based on a target value estimated from the data, which we take to be the
homoscedastic variance. Nevertheless, the present work does not only focus on
classification recovery, but also on how well model parameters are estimated.
In particular, the paper sheds light on the shrinkage-like interpretation of
the procedure, where the target is the homoscedastic model: this is not only
related to how close to the target the estimated scales are, but extends to the
estimated clusterwise linear regressions and classification. We show, based on
simulation and real-data based results, that our approach yields a final model
being the most appropriate-to-the-data compromise between the heteroscedastic
model and the homoscedastic model.


title: Algorithmic concepts for the computation of Jacobsthal's function

abstract:
  The Jacobsthal function has aroused interest in various contexts in the past
decades. We review several algorithmic ideas for the computation of
Jacobsthal's function for primorial numbers and discuss their practicability
regarding computational effort. The respective function values were computed
for primes up to 251. In addition to the results including previously unknown
data, we provide exhaustive lists of all sequences of the appropriate maximum
lengths in ancillary files.


title:
Non-Markovian Closure Models for Large Eddy Simulations using the
  Mori-Zwanzig Formalism

abstract:
  This work uses the Mori-Zwanzig (M-Z) formalism, a concept originating from
non-equilibrium statistical mechanics, as a basis for the development of
coarse-grained models of turbulence. The mechanics of the generalized Langevin
equation (GLE) are considered and insight gained from the orthogonal dynamics
equation is used as a starting point for model development. A class of sub-grid
models is considered which represent non-local behavior via a finite memory
approximation (Stinis, P., "Mori-Zwanzig reduced models for uncertainty
quantification I: Parametric uncertainty," \textit{arXiv:1211.4285}, 2012.),
the length of which is determined using a heuristic that is related to the
spectral radius of the Jacobian of the resolved variables. The resulting models
are intimately tied to the underlying numerical resolution and are capable of
approximating non-Markovian effects. Numerical experiments on the Burgers
equation demonstrate that the M-Z-based models can accurately predict the
temporal evolution of the total kinetic energy and the total dissipation rate
at varying mesh resolutions. The trajectory of each resolved mode in
phase-space is accurately predicted for cases where the coarse-graining is
moderate. LES of homogeneous isotropic turbulence and the Taylor Green Vortex
show that the M-Z-based models are able to provide excellent predictions,
accurately capturing the sub-grid contribution to energy transfer. Lastly, LES
of fully developed channel flow demonstrate the applicability of M-Z-based
models to non-decaying problems. It is notable that the form of the closure is
not imposed by the modeler, but is rather derived from the mathematics of the
coarse-graining, highlighting the potential of M-Z-based techniques to define
LES closures.


title:
A phenomenological study on the production of Higgs bosons in the cSMCS
  model at the LHC

abstract:
  In the present work, we intend to predict the production rates of the Higgs
bosons in the simplest extension of the Standard Model (SM) by a neutral
complex singlet (cSMCS). This model has an additional source of CP violation
and provides strong enough first-order electroweak phase transition to generate
the baryon asymmetry of universe (BAU). The scalar spectrum of the cSMCS
includes three neutral Higgs particles with the lightest one considered to be
the 125 GeV Higgs boson found at LHC. The SM-like Higgs boson comes mostly from
the SM-like SU(2) doublet, with a small correction from the singlet. To predict
the production rates of the Higgs bosons, we use a conventional effective LO
QCD framework and the unintegrated parton distribution functions (UPDF) of
Kimber-Martin-Ryskin (KMR). We first compute the SM Higgs production
cross-section and compare the results to the existing theoretical calculations
from different frameworks as well as the experimental data from the CMS and
ATLAS collaborations. It is shown that our framework is capable of producing
sound predictions for these high-energy QCD events in the SM. Afterwards we
present our predictions for the Higgs boson production in the cSMCS.


title: X-ray Scattering Image Classification Using Deep Learning

abstract:
  Visual inspection of x-ray scattering images is a powerful technique for
probing the physical structure of materials at the molecular scale. In this
paper, we explore the use of deep learning to develop methods for automatically
analyzing x-ray scattering images. In particular, we apply Convolutional Neural
Networks and Convolutional Autoencoders for x-ray scattering image
classification. To acquire enough training data for deep learning, we use
simulation software to generate synthetic x-ray scattering images. Experiments
show that deep learning methods outperform previously published methods by 10\%
on synthetic and real datasets.


title:
Locally favoured structures and dynamic length scales in a simple
  glass-former

abstract:
  We investigate the static and dynamic properties of a weakly polydisperse
hard sphere system in the deeply supercooled state, i.e. at densities higher
than that corresponding to the mode-coupling transition. The structural
analysis reveals the emergence of icosahedral locally favoured structures,
previously only found in trace quantities. We present a new approach to probe
the shape of dynamically heterogeneous regions, which is insensitive to
particle packing effects that can hamper such analysis. Our results indicate
that the shape of the dynamically heterogeneous regions changes only weakly and
moreover hint that the often-used four-point correlation length may exhibit a
growth in excess of that which our method identifies. The growth of the size of
the dynamically heterogeneous regions appears instead to be in line with the
one of structural and dynamic propensity correlations.


title:
Valence fuctuation and magnetic ordering in EuNi2(P1-xGex)2 single
  crystals

abstract:
  Unusual phases and phase transitions are seen at the magnetic-nonmagnetic
boundary in Ce, Eu and Yb-based compounds. EuNi$_2$P$_{2}$ is a very unusual
valence fluctuating Eu system, because at low temperatures the Eu valence stays
close to 2.5 instead of approaching an integer value. Eu valence and thus the
magnetic property in this system can be tuned by Ge substitution in P site as
EuNi$_2$Ge$_{2}$ is known to exhibit antiferromagnetc (AFM) ordering of
divalent Eu moments with $T_N$ = 30 K. We have grown
EuNi$_2$(P$_{1-x}$Ge$_x$)$_2$ (0.0 $\leq$ $x$ $\leq$ 0.5) single crystals and
studied their magnetic, thermodynamic and transport properties. Increasing Ge
doping to $x >$ 0.4 results in a well-defined AFM ordered state with $T_N$ = 12
K for $x$ = 0.5. Moreover, the reduced value of magnetic entropy for $x$ = 0.5
at $T_N$ suggests the presence of valance fluctuation/ Kondo effect in this
compound. Interestingly, the specific heat exhibits an enhanced Sommerfeld
coefficient upon Ge doping. Subsequently, electronic structure calculations
lead to a non-integral valence in EuNi$_2$P$_{2}$ but a stable divalent Eu
state in EuNi$_2$Ge$_{2}$ which is in good agreement with experimental results.


title: Clockwork Inflation

abstract:
  We investigate the recently proposed clockwork mechanism delivering light
degrees of freedom with suppressed interactions and show, with various
examples, that it can be efficiently implemented in inflationary scenarios to
generate flat inflaton potentials and small density perturbations without
fine-tunings. We also study the clockwork graviton in de Sitter and,
interestingly, we find that the corresponding clockwork charge is
site-dependent. As a consequence, the amount of tensor modes is generically
suppressed with respect to the standard cases where the clockwork set-up is not
adopted. This point can be made a virtue in resurrecting models of inflation
which were supposed to be ruled out because of the excessive amount of tensor
modes from inflation.


title:
Antiferroelectric instability in kagome francisites
  Cu$_3$Bi(SeO$_3$)$_2$O$_2$X (X = Cl, Br)

abstract:
  Density-functional calculations of lattice dynamics and high-resolution
synchrotron powder diffraction uncover antiferroelectric distortion in the
kagome francisite Cu$_3$Bi(SeO$_3$)$_2$O$_2$Cl below 115K. Its Br-containing
analogue is stable in the room-temperature crystal structure down to at least
10K, although the Br compound is on the verge of a similar antiferroelectric
instability and reveals local displacements of Cu and Br atoms. The
I-containing compound is stable in its room-temperature structure according to
density-functional calculations. We show that the distortion involves
cooperative displacements of Cu and Cl atoms, and originates from the
optimization of interatomic distances for weakly bonded halogen atoms. The
distortion introduces a tangible deformation of the kagome spin lattice and may
be responsible for the reduced net magnetization of the Cl compound compared to
the Br one. The polar structure of Cu$_3$Bi(SeO$_3$)$_2$O$_2$Cl is only
slightly higher in energy than the non-polar antiferroelectric structure, but
no convincing evidence of its formation could be obtained.


title:
Variables effecting photomosaic reconstruction and ortho-rectification
  from aerial survey datasets

abstract:
  Unmanned aerial vehicles now make it possible to obtain high quality aerial
imagery at a low cost, but processing those images into a single, useful entity
is neither simple nor seamless. Specifically, there are factors that must be
addressed when merging multiple images into a single coherent one. While
ortho-rectification can be done, it tends to be expensive and time consuming.
Image stitching offers a more economical, low-tech approach. However direct
application tends to fail for low-elevation imagery due to one or more factors
including insufficient keypoints, parallax issues, and homogeneity of the
surveyed area. This paper discusses these problems and possible solutions when
using techniques such as image stitching and structure from motion for
generating ortho-rectified imagery. These are presented in terms of actual
Irish projects including the Boland's Mills building in Dublin's city centre,
the Kilmoon Cross Farm, and the Richview buildings on the University College
Dublin campus. Implications for various Irish industries are explained in terms
of both urban and rural projects.


title:
Logarithmic NLS equation on star graphs: existence and stability of
  standing waves

abstract:
  In this paper we consider the logarithmic Schr\"{o}dinger equation on a star
graph. By using a compactness method, we construct a unique global solution of
the associated Cauchy problem in a suitable functional framework. Then we show
the existence of several families of standing waves. We also prove the
existence of ground states as minimizers of the action on the Nehari manifold.
Finally, we show that the ground states are orbitally stable via a variational
approach.


title:
Electrocardiogram signal denoising using non-local wavelet transform
  domain filtering

abstract:
  ECG signals are usually corrupted by baseline wander, power-line
interference, muscle noise, etc. and numerous methods have been proposed to
remove these noises. However, in case of wireless recording of the ECG signal
it gets corrupted by the additive white Gaussian noise (AWGN). For the correct
diagnosis, removal of AWGN from ECG signals becomes necessary as it affects the
all the diagnostic features. The natural signals exhibit correlation among
their samples and this property has been exploited in various signal
restoration tasks. Motivated by that, in this work we propose a nonlocal
wavelet transform domain ECG signal denoising method which exploits the
correlations among both local and nonlocal samples of the signal. In the
proposed method, the similar blocks of the samples are grouped in a matrix and
then denoising is achieved by the shrinkage of its two-dimensional discrete
wavelet transform coefficients. The experiments performed on a number of ECG
signals show significant quantitative and qualitative improvement in denoising
performance over the existing ECG signal denoising methods.


title: Computing threshold functions using dendrites

abstract:
  Neurons, modeled as linear threshold unit (LTU), can in theory compute all
thresh- old functions. In practice, however, some of these functions require
synaptic weights of arbitrary large precision. We show here that dendrites can
alleviate this requirement. We introduce here the non-Linear Threshold Unit
(nLTU) that integrates synaptic input sub-linearly within distinct subunits to
take into account local saturation in dendrites. We systematically search
parameter space of the nTLU and TLU to compare them. Firstly, this shows that
the nLTU can compute all threshold functions with smaller precision weights
than the LTU. Secondly, we show that a nLTU can compute significantly more
functions than a LTU when an input can only make a single synapse. This work
paves the way for a new generation of network made of nLTU with binary
synapses.


title: Verification of Logical Consistency in Robotic Reasoning

abstract:
  Most autonomous robotic agents use logic inference to keep themselves to safe
and permitted behaviour. Given a set of rules, it is important that the robot
is able to establish the consistency between its rules, its perception-based
beliefs, its planned actions and their consequences. This paper investigates
how a robotic agent can use model checking to examine the consistency of its
rules, beliefs and actions. A rule set is modelled by a Boolean evolution
system with synchronous semantics, which can be translated into a labelled
transition system (LTS). It is proven that stability and consistency can be
formulated as computation tree logic (CTL) and linear temporal logic (LTL)
properties. Two new algorithms are presented to perform realtime consistency
and stability checks respectively. Their implementation provides us a
computational tool, which can form the basis of efficient consistency checks
on-board robots.


title: Quantum ratchet in disordered quantum walk

abstract:
  Symmetrically evolving discrete quantum walk results in dynamic localization
with zero mean displacement when the standard evolution operations are replaced
by a temporal disorder evolution operation. In this work we show that the
quantum ratchet action, that is, a directed transport in standard or disordered
discrete-time quantum walk can be realized by introducing a pawl like effect
realized by using a fixed coin operation at marked positions that is, different
from the ones used for evolution at other positions. We also show that the
combination of standard and disordered evolution operations can be optimized to
get the mean displacement of order $\propto$ t (number of walk steps). This
model of quantum ratchet in quantum walk is defined using only a set of
entangling unitary operators resulting in the coherent quantum transport.


title: Effect of Noncommutativity of Space-time on Zitterbewegung

abstract:
  In this paper, we present the results of our investigation on the
modification of Zitterbewegung due to the noncommutativity of the space-time.
First, we study the effect of $\kappa$-deformation of the space-time on
Zitterbewegung. For this, we start with the $\kappa$-deformed Dirac theory and
using $\kappa$-deformed Dirac equation valid upto first order in deformation
parameter $a$, we find the modification in the Zitterbewegung valid upto first
order in the deformation parameter $a$. In the limit $a\rightarrow 0$, we get
back the commutative result. Secondly, we find the modification in the
Zitterbewegung due to the Magueijo-Smolin(MS) approach of doubly special
relativity(DSR) and in the limit $E_p \rightarrow \infty$, we get back the
result in the commutative space-time.


title: Effects of Fieldline Topology on Energy Propagation in the Corona

abstract:
  We study the effect of photospheric footpoint motions on magnetic field
structures containing magnetic nulls. The footpoint motions are prescribed on
the photospheric boundary as a velocity field which entangles the magnetic
field. We investigate the propagation of the injected energy, the conversion of
energy, emergence of current layers and other consequences of the non-trivial
magnetic field topology in this situation. These boundary motions lead
initially to an increase in magnetic and kinetic energy. Following this, the
energy input from the photosphere is partially dissipated and partially
transported out of the domain through the Poynting flux. The presence of
separatrix layers and magnetic null-points fundamentally alters the propagation
behavior of disturbances from the photosphere into the corona. Depending on the
field line topology close to the photosphere, the energy is either trapped or
free to propagate into the corona.


title:
Equilibration of a strongly interacting plasma: holographic analysis of
  local and nonlocal probes

abstract:
  The relaxation of a strongly coupled plasma towards the hydrodynamic regime
is studied by analyzing the evolution of local and nonlocal observables in the
holographic approach. The system is driven in an initial anisotropic and
far-from equilibrium state through an impulsive time-dependent deformation
(quench) of the boundary spacetime geometry. Effective temperature and entropy
density are related to the position and area of a black hole horizon, which has
formed as a consequence of the distortion. The behavior of stress-energy
tensor, equal-time correlation functions and Wilson loops of different shapes
is examined, and a hierarchy among their thermalization times emerges: probes
involving shorter length scales thermalize faster.


title:
Early Evolution of Bird-Type Language without Grammar: Duplication and
  Mutation

abstract:
  Using a series of computer simulations we have demonstrated a scenario of the
early evolution of the bird-type primitive language. We do not assume wise
agents who can use a grammar and manage an evolution without a grammar.
Duplication and mutation of phrases is our strategy. Such a strategy is seen in
wide classes of living phenomena.


title: Distributed Estimation and Learning over Heterogeneous Networks

abstract:
  We consider several estimation and learning problems that networked agents
face when making decisions given their uncertainty about an unknown variable.
Our methods are designed to efficiently deal with heterogeneity in both size
and quality of the observed data, as well as heterogeneity over time
(intermittence). The goal of the studied aggregation schemes is to efficiently
combine the observed data that is spread over time and across several network
nodes, accounting for all the network heterogeneities. Moreover, we require no
form of coordination beyond the local neighborhood of every network agent or
sensor node. The three problems that we consider are (i) maximum likelihood
estimation of the unknown given initial data sets, (ii) learning the true model
parameter from streams of data that the agents receive intermittently over
time, and (iii) minimum variance estimation of a complete sufficient statistic
from several data points that the networked agents collect over time. In each
case we rely on an aggregation scheme to combine the observations of all
agents; moreover, when the agents receive streams of data over time, we modify
the update rules to accommodate the most recent observations. In every case, we
demonstrate the efficiency of our algorithms by proving convergence to the
globally efficient estimators given the observations of all agents. We
supplement these results by investigating the rate of convergence and providing
finite-time performance guarantees.

categories: stat.AP cs.SI cs.SY math.ST stat.ML stat.TH


title:
Three-dimensional multiple-relaxation-time lattice Boltzmann model for
  convection heat transfer in porous media at the REV scale

abstract:
  In this paper, a three-dimensional (3D) multiple-relaxation-time (MRT)
lattice Boltzmann (LB) model is presented for convection heat transfer in
porous media at the representative elementary volume (REV) scale. The model is
developed in the framework of the double-distribution-function (DDF) approach:
an MRT-LB model of the density distribution function with the D3Q19 lattice (or
D3Q15 lattice) is proposed to simulate the flow field based on the generalized
non-Darcy model, while an MRT-LB model of the temperature distribution function
with the D3Q7 lattice is proposed to simulate the temperature filed. The
present model is employed to simulate mixed convection flow in a porous channel
and natural convection in a cubical porous cavity. The numerical results
demonstrate the effectiveness and accuracy of the present model in solving 3D
convection heat transfer problems in porous media. The numerical results also
demonstrate that the present model is approximately second-order accuracy in
space. In addition, an enthalpy-based DDF-MRT model for 3D solid-liquid phase
change with convection heat transfer in porous media is also presented.


title:
The vital role of hole-carriers for superconductivity in pressurized
  black phosphorus

abstract:
  The influence of carrier type on superconductivity has been an important
issue for understanding both conventional and unconventional superconductors
[1-7]. For elements that superconduct, it is known that hole-carriers govern
the superconductivity for transition and main group metals [8-10]. The role of
hole-carriers in elements that are not normally conducting but can be converted
to superconductors, however, remains unclear due to the lack of experimental
data. Here we report the first in-situ high pressure Hall effect measurements
on single crystal black phosphorus, measured up to ~ 50 GPa, and find a
correlation between the Hall coefficient and the superconducting transition
temperature (TC). Our results reveal that hole-carriers play a vital role in
developing superconductivity and enhancing TC. Importantly, we also find a
Lifshitz transition in the high-pressure cubic phase at ~17.2GPa, which
uncovers the origin of a puzzling valley in the superconducting TC-pressure
phase diagram. These results offer insight into the role of hole-carriers in
developing superconductivity in simple semiconducting solids under pressure.


title:
Full characterizations of the variational McShane Integral on
  $m$-dimensional compact intervals

abstract:
  In this paper we consider the additive interval functions defined on the
family $\mathcal{I}_{m}$ of all non-degenerate closed subintervals of the cubic
interval $C_{m} = [0,1]^{m}$ in the $m$-dimensional Euclidean space
$\mathbb{R}^{m}$ and taking values in a Banach space $X$. We give necessary and
sufficient conditions for an additive interval function $F : \mathcal{I}_{m}
\to X$ to be the primitive of a variational McShane (or strong McShane)
integrable function $f : C_{m} \to X$ in terms of the convex cubic average
range of $F$.


title: Pick-up and impact of flexible bodies

abstract:
  Picking up, laying down, colliding, rolling, and peeling are partial-contact
interactions involving moving discontinuities. We examine the balances of
momentum and energy across a moving discontinuity in a string, with allowance
for injection or dissipation by singular supplies. We split the energy
dissipation according to its invariance properties, discuss analogies with
systems of particles and connections with the literature on shocks and phase
transition fronts in various bodies, and derive a compatibility relation
between supplies of momentum and translation-invariant energy. For a moving
contact discontinuity between a string and a smooth rigid plane in the presence
of gravity, we find a surprising asymmetry between the processes of picking up
and laying down, such that steady-state kinks in geometry and associated jumps
in tension are not admissible during pick-up. This prediction is consistent
with experimental observations. We briefly discuss related problems including
the falling folded chain, peeling of an adhesive tape, and the "chain
fountain". Our approach is applicable to the study of impact and locomotion,
and to systems such as moored floating structures and some musical instruments
that feature vibrating string and cable elements interacting with a surface.


title:
The Fock-Kemmer approach to precursor shock waves in relativistic field
  theory

abstract:
  We use distribution theory (generalized functions) to extend and justify the
Fock-Kemmer approach to the propagation of precursor shock wave discontinuities
in classical and quantum field theory. We apply lightcone causality arguments
to propose that shock wave singularities in non-linear classical field theories
and in Maxwell's equations for responsive media require a form of classical
renormalization analogous to Wilson operator product expansions in quantum
field theories.


title:
Studies of the Long Secondary Periods in Pulsating Red Giants. II.
  Lower-Luminosity Stars

abstract:
  We have used AAVSO visual and photoelectric V data, and the AAVSO time-series
package VSTAR and the Lomb-Scargle time-series algorithm to determine improved
pulsation periods, "long secondary periods" (LSPs). and their amplitudes in 51
shorter-period pulsating red giants in the AAVSO photoelectric photometry
program, and the AAVSO LPV (long period variable) binocular program. As is well
known, radial pulsation becomes detectable in red giants at about spectral type
M0, with periods of about 20 days. We find that the LSP phenomenon is also
first detectable at about M0. Pulsation and LSP amplitudes increase from near
zero to about 0.1 at pulsation periods of about 100 days. At longer periods,
the pulsation amplitudes continue to increase, but the LSP amplitudes are
generally between 0.1 and 0.2 on average. The ratios of LSP to pulsation period
cluster around 5 and 10, presumably depending on whether the pulsation period
is the fundamental or first overtone. The pulsation and LSP phase curves are
generally close to sinusoidal, except when the amplitude is small, in which
case they may be distorted by observational scatter or, in the case of the LSP
amplitude, by the pulsational variability. As with longer-period stars, the LSP
amplitude increases and decreases by a factor of two or more, for unknown
reasons, on a median time scale of about 20 LSPs. The LSP phenomenon is thus
present and simiklar in radially pulsating red giants of all periods. Its cause
remains unknown.


title: Machine learning methods for nanolaser characterization

abstract:
  Nanocavity lasers, which are an integral part of an on-chip integrated
photonic network, are setting stringent requirements on the sensitivity of the
techniques used to characterize the laser performance. Current characterization
tools cannot provide detailed knowledge about nanolaser noise and dynamics. In
this progress article, we will present tools and concepts from the Bayesian
machine learning and digital coherent detection that offer novel approaches for
highly-sensitive laser noise characterization and inference of laser dynamics.
The goal of the paper is to trigger new research directions that combine the
fields of machine learning and nanophotonics for characterizing nanolasers and
eventually integrated photonic networks


title:
Exact Throughput Analysis of Random CoopMAC Networks in the Presence of
  Shadowing

abstract:
  The throughput performance of a random cooperative medium access control
(CoopMAC) network in the presence of shadowing is considered. The nodes are
assumed to be randomly distributed according to a homogeneous two-dimensional
Poisson point process with constant intensity. The conditions under which a
helper can improve the transmission rate between a given pair of nodes are
examined. Based on these conditions, an exact analytical expression is derived
for the average cooperative throughput of a random CoopMAC network that is
subject to path loss and shadowing. This expression is then used to investigate
the effects of shadowing, intensity of nodes and the distance between source
and destination nodes on the cooperative throughput of the network. It is
observed that the average cooperative throughput of the network increases only
slightly when the intensity of helpers increases beyond a certain value.


title:
A tunable electronic beam splitter realized with crossed graphene
  nanoribbons

abstract:
  Graphene nanoribbons (GNRs) are promising components in future
nanoelectronics due to the large mobility of graphene electrons and their
tunable electronic band gap in combination with recent experimental
developments of on-surface chemistry strategies for their growth. Here we
explore a prototype 4-terminal semiconducting device formed by two crossed
armchair GNRs (AGNRs) using state-of-the-art first-principles transport
methods. We analyze in detail the roles of intersection angle, stacking order,
inter-GNR separation, and finite voltages on the transport characteristics.
Interestingly, when the AGNRs intersect at $\theta= 60^\circ$, electrons
injected from one terminal can be split into two outgoing waves with a tunable
ratio around 50% and with almost negligible back-reflection. The splitted
electron wave is found to propagate partly straight across the intersection
region in one ribbon and partly in one direction of the other ribbon, i.e., in
analogy of an optical beam splitter. Our simulations further identify realistic
conditions for which this semiconducting device can act as a mechanically
controllable electronic beam splitter with possible applications in
carbon-based quantum electronic circuits and electron optics. We rationalize
our findings with a simple model that suggests that electronic beam splitters
can generally be realized with crossed GNRs.


title: Method of Relaxed Streamline Upwinding for Hyperbolic Conservation Laws

abstract:
  In this work a new finite element based Method of Relaxed Streamline
Upwinding is proposed to solve hyperbolic conservation laws. Formulation of the
proposed scheme is based on relaxation system which replaces hyperbolic
conservation laws by semi-linear system with stiff source term also called as
relaxation term. The advantage of the semi-linear system is that the
nonlinearity in the convection term is pushed towards the source term on right
hand side which can be handled with ease. Six symmetric discrete velocity
models are introduced in two dimensions which symmetrically spread foot of the
characteristics in all four quadrants thereby taking information symmetrically
from all directions. Proposed scheme gives exact diffusion vectors which are
very simple. Moreover, the formulation is easily extendable from scalar to
vector conservation laws. Various test cases are solved for Burgers equation
(with convex and non-convex flux functions), Euler equations and shallow water
equations in one and two dimensions which demonstrate the robustness and
accuracy of the proposed scheme. New test cases are proposed for Burgers
equation, Euler and shallow water equations. Exact solution is given for
two-dimensional Burgers test case which involves normal discontinuity and
series of oblique discontinuities. Error analysis of the proposed scheme shows
optimal convergence rate. Moreover, spectral stability analysis gives implicit
expression of critical time step.


title: Limits of some weighted Cesaro averages

abstract:
  We investigate the existence of the limit of some high order weighted Cesaro
averages.


title:
Privacy of the Internet of Things: A Systematic Literature Review
  (Extended Discussion)

abstract:
  The Internet of Things' potential for major privacy invasion is a concern.
This paper reports on a systematic literature review of privacy-preserving
solutions appearing in the research literature and in the media. We analysed
proposed solutions in terms of the techniques they deployed and the extent to
which they satisfied core privacy principles. We found that very few solutions
satisfied all core privacy principles. We also identified a number of key
knowledge gaps in the course of the analysis. In particular, we found that most
solution providers assumed that end users would be willing to expend effort to
preserve their privacy; that they would be motivated to act to preserve their
privacy. The validity of this assumption needs to be proved, since it cannot
simply be assumed that people would necessarily be willing to engage with these
solutions. We suggest this as a topic for future research.


title:
Fast Algorithm of High-resolution Microwave Imaging Using the
  Non-parametric Generalized Reflectivity Model

abstract:
  This paper presents an efficient algorithm of high-resolution microwave
imaging based on the concept of generalized reflectivity. The contribution made
in this paper is two-fold. We introduce the concept of non-parametric
generalized reflectivity (GR, for short) as a function of operational
frequencies and view angles, etc. The GR extends the conventional Born-based
imaging model, i.e., single-scattering model, into that accounting for more
realistic interaction between the electromagnetic wavefield and imaged scene.
Afterwards, the GR-based microwave imaging is formulated in the convex of
sparsity-regularized optimization. Typically, the sparsity-regularized
optimization requires the implementation of iterative strategy, which is
computationally expensive, especially for large-scale problems. To break this
bottleneck, we convert the imaging problem into the problem of physics-driven
image processing by introducing a dual transformation. Moreover, this image
processing is performed over overlapping patches, which can be efficiently
solved in the parallel or distributed manner. In this way, the proposed
high-resolution imaging methodology could be applicable to large-scale
microwave imaging problems. Selected simulation results are provided to
demonstrate the state-of-art performance of proposed methodology.


title:
Suppressing and restoring the Dicke superradiance transition by
  dephasing and decay

abstract:
  We show that dephasing of individual atoms destroys the superradiance
transition of the Dicke model, but that adding individual decay toward the spin
down state can restore this transition. To demonstrate this, we present a
method to give an exact solution for the $N$ atom problem with individual
dephasing which scales polynomially with $N$. By comparing finite size scaling
of our exact solution to a cumulant expansion, we confirm the destruction and
restoration of the superradiance transition holds in the thermodynamic limit.


title: Fuzzy Logic-based Implicit Authentication for Mobile Access Control

abstract:
  In order to address the increasing compromise of user privacy on mobile
devices, a Fuzzy Logic based implicit authentication scheme is proposed in this
paper. The proposed scheme computes an aggregate score based on selected
features and a threshold in real-time based on current and historic data
depicting user routine. The tuned fuzzy system is then applied to the
aggregated score and the threshold to determine the trust level of the current
user. The proposed fuzzy-integrated implicit authentication scheme is designed
to: operate adaptively and completely in the background, require minimal
training period, enable high system accuracy while provide timely detection of
abnormal activity. In this paper, we explore Fuzzy Logic based authentication
in depth. Gaussian and triangle-based membership functions are investigated and
compared using real data over several weeks from different Android phone users.
The presented results show that our proposed Fuzzy Logic approach is a highly
effective, and viable scheme for lightweight real-time implicit authentication
on mobile devices.


title:
One-step fabrication of metal nanostructures by high-throughput
  imprinting

abstract:
  Direct nanoimprinting provides a simple and high-throughput route for
producing uniform nanopatterns at great precision and at low costs. However,
applying this technique to crystalline metals has been considered as impossible
due to intrinsic limitation from grain size effect. Here we demonstrate direct
superplastic nanoimprinting (SPNI) of crystalline metals well below their
melting temperatures (Tm), generating ordered nanowire arrays with aspect ratio
up to ~2000. Our investigations of replicating metal hierarchical
nanostructures show the capability of imprinting features as small as 8 nm, far
smaller than the grain size of bulk metals. Most surprisingly, the prepared
metal hierarchical nanostructures were found possessing perfect monocrystalline
structures. These findings indicate that nanoimprinting of crystalline metals
below Tm might be from lattice diffusion. SPNI as a one-step and highly
controlled high-throughput fabrication method, could facilitate the
applications of metal nanostructures in bio-sensing, diagnostic imaging,
catalysis, food industry and environmental conservation.