title:
A concise approach to small generating sets of lattices of quasiorders
  and transitive relations

abstract:
  By H. Strietz, 1975, and G. Cz\'edli, 1996, the complete lattice $Equ(A)$ of
all equivalences is four-generated, provided the size $|A|$ is an accessible
cardinal. Results of I. Chajda and G. Cz\'edli, 1996, G. Tak\'ach, 1996, T.
Dolgos, 2015, and J.\ Kulin 2016, show that both the lattice $Quo(A)$ of all
quasiorders on $A$ and, for $|A|\leq \aleph_0$, the lattice $Tran(A)$ of all
transitive relations on $A$ have small generating sets. Based on complicated
earlier constructions, we derive some new results in a concise but not
self-contained way.


title: Crowdsourcing Information Extraction for Biomedical Systematic Reviews

abstract:
  Information extraction is a critical step in the practice of conducting
biomedical systematic literature reviews. Extracted structured data can be
aggregated via methods such as statistical meta-analysis. Typically highly
trained domain experts extract data for systematic reviews. The high expense of
conducting biomedical systematic reviews has motivated researchers to explore
lower cost methods that achieve similar rigor without compromising quality.
Crowdsourcing represents one such promising approach. In this work-in-progress
study, we designed a crowdsourcing task for biomedical information extraction.
We briefly report the iterative design process and the results of two pilot
testings. We found that giving more concrete examples in the task instruction
can help workers better understand the task, especially for concepts that are
abstract and confusing. We found a few workers completed most of the work, and
our payment level appeared more attractive to workers from low-income
countries. In the future, we will further evaluate our results with reference
to gold standard extractions, thus assessing the feasibility of tasking crowd
workers with extracting biomedical intervention information for systematic
reviews.


title:
Testing Type II Radiative Seesaw Model: from Dark Matter Detection to
  LHC Signatures

abstract:
  We analyse the testability of the type II radiative seesaw in which neutrino
mass and dark matter (DM) are related at one-loop level. Under the constraints
from DM relic density, direct and indirect detection, and invisible Higgs
decays, we find three possible regions of DM mass $M_{s_1}$ that can survive
the present and even the future experiments: (1) the Higgs resonance region
with $M_{s_1}\sim M_h/2$, (2) the Higgs region with $M_{s_1}\sim M_h$, and (3)
the coannihilation region with $M_{s_2}\sim M_{s_1}$. Here $s_{1,2}$ are two
scalar singlets with the lighter $s_1$ being the DM candidate. Based on DM
properties and direct collider constraints, we choose three benchmark points to
illustrate the testability of this model at LHC. We perform a detailed
simulation of the four-lepton and tri-lepton signatures at 13 (14) TeV LHC.
While both signatures are found to be promising at all benchmark points, the
tri-lepton one is even better: it is possible to reach the $5\sigma$
significance with an integrated luminosity of 100/fb.


title:
Combining SOS and Moment Relaxations with Branch and Bound to Extract
  Solutions to Global Polynomial Optimization Problems

abstract:
  In this paper, we present a branch and bound algorithm for extracting
approximate solutions to Global Polynomial Optimization (GPO) problems with
bounded feasible sets.
  The algorithm is based on a combination of SOS/Moment relaxations and
successively bisecting a hyper-rectangle containing the feasible set of the GPO
problem. At each iteration, the algorithm makes a comparison between the volume
of the hyper-rectangles and their associated lower bounds to the GPO problem
obtained by SOS/Moment relaxations to choose and subdivide an existing
hyper-rectangle. For any desired accuracy, if we use sufficiently large order
of SOS/Moment relaxations, then the algorithm is guaranteed to return a
suboptimal point in a certain sense. For a fixed order of SOS/Moment
relaxations, the complexity of the algorithm is linear in the number of
iterations and polynomial in the number of constrains. We illustrate the
effectiveness of the algorithm for a 6-variable, 5-constraint GPO problem for
which the ideal generated by the equality constraints is not zero-dimensional -
a case where the existing Moment-based approach for extracting the global
minimizer might fail.


title:
Cationic Effect on Pressure driven Spin-State Transition and
  cooperativity in Hybrid Perosvkites

abstract:
  Hybrid or metal organic framework (MOF) perovskites of general composition,
ABX$_3$, are known to show interesting properties which can lead to variety of
technological applications. Our first principles study shows they are also
potential candidates for exhibiting cooperative spin-state transitions upon
application of external stimuli. We demonstrate this by considering two
specific Fe-based MOF perovskites, namely Dimethylammonium Iron Formate,
[CH$_{3}$NH$_{2}$CH$_{3}$][Fe(HCOO)$_3$] and Hydroxylammonium Iron Formate,
[NH$_{3}$OH][Fe(HCOO)$_3$]. Both the compounds are found to undergo high-spin
(S=2) to low-spin (S=0) transition at Fe(II) site upon application of moderate
strength of hydrostatic pressure, along with large hysteresis. This spin-state
transition is signaled by the changes in electronic, magnetic and optical
properties. We find both the transition pressure and the width of the
hysteresis to be strongly dependent of the choice of A-site cation,
Dimethylammonium or Hydroxylammonium, implying tuning of spin-switching
properties achievable by chemical variation of the amine cation in the
structure. Our finding opens up novel functionalities in this family of
materials of recent interest, which can have important usage in sensors and
memory devices.


title: Spin excitations in optimally P-doped BaFe2(As0.7P0.3)2superconductor

abstract:
  We use inelastic neutron scattering to study temperature and energy
dependence of spin excitations in optimally P-doped BaFe2(As0.7P0.3)2
superconductor (Tc = 30 K) throughout the Brillouin zone. In the undoped state,
spin waves and paramagnetic spin excitations of BaFe2As2 stem from
antiferromagnetic (AF) ordering wave vector QAF= (1/-1,0) and peaks near zone
boundary at (1/-1,1/-1) around 180 meV. Replacing 30% As by smaller P to induce
superconductivity, low-energy spin excitations of BaFe2(As0.7P0.3)2form a
resonance in the superconducting state and high-energy spin excitations now
peaks around 220 meV near (1/-1,1/-1). These results are consistent with
calculations from a combined density functional theory and dynamical mean field
theory, and suggest that the decreased average pnictogen height in
BaFe2(As0.7P0.3)2 reduces the strength of electron correlations and increases
the effective bandwidth of magnetic excitations.


title: Local Kernel Dimension Reduction in Approximate Bayesian Computation

abstract:
  Approximate Bayesian Computation (ABC) is a popular sampling method in
applications involving intractable likelihood functions. Without evaluating the
likelihood function, ABC approximates the posterior distribution by the set of
accepted samples which are simulated with parameters drawn from the prior
distribution, where acceptance is determined by the distance between the
summary statistics of the sample and the observation. The sufficiency and
dimensionality of the summary statistics play a central role in the application
of ABC. This paper proposes Local Gradient Kernel Dimension Reduction (LGKDR)
to construct low dimensional summary statistics for ABC. The proposed method
identifies a sufficient subspace of the original summary statistics by
implicitly considers all nonlinear transforms therein, and a weighting kernel
is used for the concentration of the projections. No strong assumptions are
made on the marginal distributions nor the regression model, permitting usage
in a wide range of applications. Experiments are done with both simple
rejection ABC and sequential Monte Carlo ABC methods. Results are reported as
competitive in the former and substantially better in the latter cases in which
Monte Carlo errors are compressed as much as possible.


title:
Simulated annealing for three-dimensional low-beta reduced MHD
  equilibria in cylindrical geometry

abstract:
  Simulated annealing (SA) is applied for three-dimensional (3D) equilibrium
calculation of ideal, low-beta reduced MHD in cylindrical geometry. The SA is
based on the theory of Hamiltonian mechanics. The dynamical equation of the
original system, low-beta reduced MHD in this study, is modified so that the
energy changes monotonically while preserving the Casimir invariants in the
artificial dynamics. An equilibrium of the system is given by an extremum of
the energy, therefore SA can be used as a method for calculating ideal MHD
equilibrium. Previous studies demonstrated that the SA succeeds to lead to
various MHD equilibria in two dimensional rectangular domain. In this paper,
the theory is applied to 3D equilibrium of ideal, low-beta reduced MHD. An
example of equilibrium with magnetic islands, obtained as a lower energy state,
is shown. Several versions of the artificial dynamics are developed that can
effect smoothing.


title:
Nonleptonic decays of $B \to ( f_1(1285),f_1(1420) ) V$ in the
  perturbative QCD approach

abstract:
  We investigate the branching ratios, the polarization fractions, the direct
CP-violating asymmetries, and the relative phases in 20 nonleptonic decay modes
of $B \to f_1 V$ within the framework of perturbative QCD approach at leading
order with $f_1$ including two $^3\!P_1$-axial-vector states $f_1(1285)$ and
$f_1(1420)$. Here, $B$ denotes $B^+$, $B^0$, and $B_s^0$ mesons and $V$ stands
for the lightest vector mesons $\rho$, $K^*$, $\omega$, and $\phi$ ,
respectively. The $B_s^0 \to f_1 V$ decays are studied theoretically for the
first time in the literature. Together with the angle $\phi_{f_1} \approx
(24^{+3.2}_{-2.7})^\circ$ extracted from the measurement through $B_{d/s} \to
J/\psi f_1(1285)$ modes for the $f_1(1285)-f_1(1420)$ mixing system, it is of
great interest to find phenomenologically some modes such as the tree-dominated
$B^+ \to f_1 \rho^+$ and the penguin-dominated $B^{+,0} \to f_1 K^{*+,0}, B_s^0
\to f_1 \phi$ with large branching ratios around ${\cal O}(10^{-6})$ or even
${\cal O}(10^{-5})$, which are expected measurable at the LHCb and/or the
Belle-II experiments in the near future. The good agreement [sharp contrast] of
branching ratios and decay pattern for $B^+ \to f_1 \rho^+, B^{+,0} \to
f_1(1285) K^{*+,0} [B^{+,0} \to f_1(1420) K^{*+,0}]$ decays between QCD
factorization and perturbative QCD factorization predictions can help us to
distinguish these two rather different factorization approaches via precision
measurements, which would also be helpful for us to explore the annihilation
decay mechanism through its important roles for the considered $B \to f_1 V$
decays.


title: Structured signal recovery from non-linear and heavy-tailed measurements

abstract:
  We study high-dimensional signal recovery from non-linear measurements with
design vectors having elliptically symmetric distribution. Special attention is
devoted to the situation when the unknown signal belongs to a set of low
statistical complexity, while both the measurements and the design vectors are
heavy-tailed. We propose and analyze a new estimator that adapts to the
structure of the problem, while being robust both to the possible model
misspecification characterized by arbitrary non-linearity of the measurements
as well as to data corruption modeled by the heavy-tailed distributions.
Moreover, this estimator has low computational complexity. Our results are
expressed in the form of exponential concentration inequalities for the error
of the proposed estimator. On the technical side, our proofs rely on the
generic chaining methods, and illustrate the power of this approach for
statistical applications. Theory is supported by numerical experiments
demonstrating that our estimator outperforms existing alternatives when data is
heavy-tailed.


title:
Return of the King: Time-Series Photometry of FO Aquarii's Initial
  Recovery from its Unprecedented 2016 Low State

abstract:
  In 2016 May, the intermediate polar FO~Aqr was detected in a low state for
the first time in its observational history. We report time-resolved photometry
of the system during its initial recovery from this faint state. Our data,
which includes high-speed photometry with cadences of just 2 sec, shows the
existence of very strong periodicities at 22.5 min and 11.26 min, equivalent to
the spin-orbit beat frequency and twice its value, respectively. A pulse at the
spin frequency is also present but at a much lower amplitude than is normally
observed in the bright state. By comparing our power spectra with theoretical
models, we infer that a substantial amount of accretion was stream-fed during
our observations, in contrast to the disk-fed accretion that dominates the
bright state. In addition, we find that FO~Aqr's rate of recovery has been
unusually slow in comparison to rates of recovery seen in other magnetic
cataclysmic variables, with an $e$-folding time of 115$\pm7$ days. The recovery
also shows irregular variations in the median brightness of as much as 0.2~mag
over a 10-day span. Finally, we show that the arrival times of the spin pulses
are dependent upon the system's overall brightness.


title: On the image of the associated form morphism

abstract:
  Let ${\mathbb C}[x_1,\dots,x_n]_{d+1}$ be the vector space of homogeneous
forms of degree $d+1$ on ${\mathbb C}^n$, with $n,d\ge 2$. In earlier articles
by J. Alper, M. Eastwood and the author, we introduced a morphism, called $A$,
that assigns to every nondegenerate form the so-called associated form lying in
the space ${\mathbb C}[y_1,\dots,y_n]_{n(d-1)}$. One of the reasons for our
interest in $A$ is the conjecture---motivated by the well-known Mather-Yau
theorem on complex isolated hypersurface singularities---asserting that all
regular ${\mathrm {GL}}_n$-invariant functions on the affine open subvariety
${\mathbb C}[x_1,\dots,x_n]_{d+1,\Delta}$ of forms with nonvanishing
discriminant can be obtained as the pull-backs by means of $A$ of the rational
${\mathrm {GL}}_n$-invariant functions on ${\mathbb C}[y_1,\dots,y_n]_{n(d-1)}$
defined on ${\mathrm {im}}(A)$. The morphism $A$ factors as $A={\mathbf A}\circ
{\mathrm {grad}}$, where ${\mathrm {grad}}$ is the gradient morphism and
${\mathbf A}$ assigns to every $n$-tuple of forms of degree $d$ with
nonvanishing resultant a form in ${\mathbb C}[y_1,\dots,y_n]_{n(d-1)}$ defined
analogously to $A(f)$ for a nondegenerate $f$. In order to establish the
conjecture, it is important to study the image of ${\mathbf A}$. In the present
paper, we show that ${\mathrm {im}}({\mathbf A})$ is an open subset of an
irreducible component of each of the so-called catalecticant varieties $V$,
${\mathrm {Gor}}(T)$ and describe the closed complement to ${\mathrm
{im}}({\mathbf A})$, at the same time clarifying and extending known results on
these varieties. Furthermore, for $n=3$, $d=2$ we give a description of the
complement to ${\mathrm {im}}({\mathbf A})$ via the zero locus of the Aronhold
invariant of degree 4, which is analogous to the case $n=2$ where this
complement is known to be the vanishing locus of the catalecticant for any
$d\ge 2$.


title:
Preserving Privacy of Agents in Participatory-Sensing Schemes for
  Traffic Estimation

abstract:
  A measure of privacy infringement for agents (or participants) travelling
across a transportation network in participatory-sensing schemes for traffic
estimation is introduced. The measure is defined to be the conditional
probability that an external observer assigns to the private nodes in the
transportation network, e.g., location of home or office, given all the
position measurements that it broadcasts over time. An algorithm for finding an
optimal trade-off between the measure of privacy infringement and the expected
estimation error, captured by the number of the nodes over which the
participant stops broadcasting its position, is proposed. The algorithm
searches over a family of policies in which an agent stops transmitting its
position measurements if its distance (in terms of the number of hops) to the
privacy sensitive node is smaller than a prescribed threshold. Employing such
symmetric policies are advantageous in terms of the resources required for
implementation and the ease of computation. The results are expanded to more
general policies. Further, the effect of the heterogeneity of the population
density on the optimal policy is explored. Finally, the relationship between
the betweenness measure of centrality and the optimal privacy-preserving policy
of the agents is numerically explored.


title: Quantum Transport in Topological Semimetals under Magnetic Fields

abstract:
  Topological semimetals are three-dimensional topological states of matter, in
which the conduction and valence bands touch at a finite number of points,
i.e., the Weyl nodes. Topological semimetals host paired monopoles and
antimonopoles of Berry curvature at the Weyl nodes and topologically protected
Fermi arcs at certain surfaces. We review our recent works on quantum transport
in topological semimetals, according to the strength of the magnetic field. At
weak magnetic fields, there are competitions between the positive
magnetoresistivity induced by the weak anti-localization effect and negative
magnetoresistivity related to the nontrivial Berry curvature. We propose a
fitting formula for the magnetoconductivity of the weak anti-localization. We
expect that the weak localization may by induced by inter- alley effects and
interaction effect, and occur in double-Weyl semimetals. For the negative
magnetoresistance induced by the nontrivial Berry curvature in topological
semimetals, we show the dependence of the negative magnetoresistance on the
carrier density. At strong magnetic fields, specifically, in the quantum limit,
the magnetoconduction depends on the type and range of the scattering potential
of disorder. The high-field positive magnetoconductivity may not be a
compelling signature of the chiral anomaly. For long-range Gaussian scattering
potential and half filling, the magnetoconductivity can be linear in the
quantum limit. A minimal conductivity is found at the Weyl nodes although the
density of states vanishes there.


title:
Device-independent characterizations of a shared quantum state
  independent of any Bell inequalities

abstract:
  In a Bell experiment two parties share a quantum state and perform local
measurements on their subsystems separately, and the statistics of the
measurement outcomes are recorded as a Bell correlation. For any Bell
correlation, it turns out {that} a quantum state with minimal size that is able
to produce this correlation can always be pure. In this work, we first exhibit
two device-independent characterizations for the pure state that Alice and Bob
share using only the correlation data. Specifically, we give two conditions
that the Schmidt coefficients must satisfy, which can be tight, and have
various applications in quantum tasks. First, one of the characterizations
allows us to bound the entanglement between Alice and Bob using Renyi entropies
and also to {bound} the underlying Hilbert space dimension. Second, when the
{Hilbert space dimension bound} is tight, the shared pure quantum state has to
be maximally entangled. Third, the second characterization gives a sufficient
condition that a Bell correlation cannot be generated by particular quantum
states. We also show that our results can be generalized to the case of shared
mixed states.


title:
Time-invariant entanglement and sudden death of nonlocality for
  multipartite systems under collective dephasing

abstract:
  We investigate the dynamics of entanglement and nonlocality for multipartite
quantum systems under collective dephasing. Using an exact and computable
measure for genuine entanglement, we demonstrate the possibility of a non
trivial phenomenon of time-invariant entanglement for multipartite quantum
systems. We find that for four qubits, there exist quantum states, which are
changing continously nevertheless their genuine entanglement remains constant.
Based on our numerical results, we conjecture that there is no evidence of
time-invariant entanglement for quantum states of three qubits. We point out
that quantum states exhibiting time-invariant entanglement must live in both
decoherence free subspace and in the subspaces orthogonal to it. The previous
studies on this feature for two qubits can be recovered from our studies as a
special case. We also study the nonlocality of quantum states under collective
dephasing. We find that although genuine entanglement of quantum states may not
change, however their nonlocality changes. We discuss the possibility of finite
time end of genuine nonlocality.


title: Countable OD sets of reals belong to the ground model

abstract:
  It is true in the Cohen, Solovay-random, dominaning, and Sacks generic
extension that every countable ordinal-definable set of reals belongs to to the
ground universe


title:
Deformations of rational surface singularities and reflexive modules
  with an application to flops

abstract:
  Blowing up a rational surface singularity in a reflexive module gives a (any)
partial resolution dominated by the minimal resolution. The main theorem shows
how deformations of the pair (singularity, module) relates to deformations of
the corresponding pair of partial resolution and locally free strict transform,
and to deformations of the underlying spaces. The results imply some recent
conjectures on small resolutions and flops.


title:
Numerical examination of commutativity between Backus and Gazis et al.
  averages

abstract:
  Dalton and Slawinski (2016) show that, in general, the Backus (1962) average
and the Gazis et al. (1963) average do not commute. Herein, we examine the
extent of this noncommutativity. We illustrate numerically that the extent of
noncommutativity is a function of the strength of anisotropy. The averages
nearly commute in the case of weak anisotropy.


title:
Estimates of lifespan and blow-up rates for the wave equation with a
  time-dependent damping and a power-type nonlinearity

abstract:
  We study blow-up behavior of solutions for the Cauchy problem of the
semilinear wave equation with time-dependent damping. When the damping is
effective, and the nonlinearity is subcritical, we show the blow-up rates and
the sharp lifespan estimates of solutions. Upper estimates are proved by an ODE
argument, and lower estimates are given by a method of scaling variables.


title: New bounds for equiangular lines and spherical two-distance sets

abstract:
  A set of lines in $\mathbb{R}^n$ is called equiangular if the angle between
each pair of lines is the same. We derive new upper bounds on the cardinality
of equiangular lines. Let us denote the maximum cardinality of equiangular
lines in $\mathbb{R}^n$ with the common angle $\arccos \alpha$ by
$M_{\alpha}(n)$. We prove that $M_{\frac 1 a} (n) \leq \frac 1 2 ( a^2-2) (
a^2-1)$ for any $n \in \mathbb{N}$ in the interval $a^2 -2 \leq n \leq 3
a^2-16$ and $a \geq 3$. Moreover, we discuss the relation between equiangular
lines and spherical two-distance sets and we obtain the new results on the
maximum spherical two-distance sets in $\mathbb{R}^n$ up to $n \leq 417$.


title: Distribution-Specific Hardness of Learning Neural Networks

abstract:
  Although neural networks are routinely and successfully trained in practice
using simple gradient-based methods, most existing theoretical results are
negative, showing that learning such networks is difficult, in a worst-case
sense over all data distributions. In this paper, we take a more nuanced view,
and consider whether specific assumptions on the "niceness" of the input
distribution, or "niceness" of the target function (e.g. in terms of
smoothness, non-degeneracy, incoherence, random choice of parameters etc.), are
sufficient to guarantee learnability using gradient-based methods. We provide
evidence that neither class of assumptions alone is sufficient: On the one
hand, for any member of a class of "nice" target functions, there are difficult
input distributions. On the other hand, we identify a family of simple target
functions, which are difficult to learn even if the input distribution is
"nice". To prove our results, we develop some tools which may be of independent
interest, such as extending Fourier-based hardness techniques developed in the
context of statistical queries \cite{blum1994weakly}, from the Boolean cube to
Euclidean space and to more general classes of functions.


title:
Highly tunable time-reversal-invariant topological superconductivity in
  topological insulator thin films

abstract:
  We study time-reversal-invariant topological superconductivity in topological
insulator (TI) thin films including both intra- and inter-surface pairing. We
find a nontrivial topology for multiple different configurations. For
intra-surface pairing a $\pi$-phase difference between the intra-surface
pairing states is required. We show that in this case the resulting topological
phase is highly tunable by both an applied electric field and varied chemical
potential. For spin-singlet inter-surface pairing, a sign-changing tunnel
coupling present in many TI thin films is needed, and again, the topology can
be tuned by electric field or doping. Notably, we find that the required
inter-surface pairing strength for achieving nontrivial topology can still be
subdominant compared to the intra-surface pairing. Finally, for spin-triplet
inter-surface pairing we prove that the superconducting state is always
topological nontrivial. We show that thin films of Cu-doped Bi$_2$Se$_3$ will
likely host such spin-triplet inter-surface pairing. Taken together, these
results show that time-reversal-invariant topological superconductivity is
common in superconducting TI thin films and that the topological phase and its
Kramers pair of Majorana edge modes is highly tunable with an applied electric
field and varied chemical potential.


title: Some properties of associated spaces with sub-Hankel determinants

abstract:
  In this note, we show that the space associated with sub-Hankel determinant
is a non-reductive, regular prehomogeneous vector space, and we give the
multiplicative Legendre transforms of sub-Hankel determinants. Moreover we
observe certain relations between $b$-functions of polarization of
PVpolynomials and $b$-functions of sub-Hankel determinants, and give some
formulas about sub-Hankel determinants whose components are orthogonal
ponlynomials.


title: Measurement of hadron cross sections with the SND detector

abstract:
  New results on exclusive hadron production in $e^+e^-$ annihilation obtained
in experiments with the SND detector at the VEPP-2M and VEPP-2000 $e^+e^-$
colliders are presented.


title: The new world atlas of artificial night sky brightness

abstract:
  Artificial lights raise night sky luminance, creating the most visible effect
of light pollution-artificial skyglow. Despite the increasing interest among
scientists in fields such as ecology, astronomy, health care, and land-use
planning, light pollution lacks a current quantification of its magnitude on a
global scale. To overcome this, we present the world atlas of artificial sky
luminance, computed with our light pollution propagation software using new
high-resolution satellite data and new precision sky brightness measurements.
This atlas shows that more than 80% of the world and more than 99% of the U.S.
and European populations live under light-polluted skies. The Milky Way is
hidden from more than one-third of humanity, including 60% of Europeans and
nearly 80% of North Americans. Moreover, 23% of the world's land surfaces
between 75{\deg}N and 60{\deg}S, 88% of Europe, and almost half of the United
States experience light-polluted nights.


title: Minimal obstructions for normal spanning trees

abstract:
  Diestel and Leader have characterised connected graphs that admit a normal
spanning tree via two classes of forbidden minors. One class are Halin's
$(\aleph_0,\aleph_1)$-graphs: bipartite graphs with bipartition
$(\mathbb{N},B)$ such that $B$ is uncountable and every vertex of $B$ has
infinite degree.
  Our main result is that under Martin's Axiom and the failure of the Continuum
Hypothesis, the class of forbidden $(\aleph_0,\aleph_1)$-graphs in Diestel and
Leader's result can be replaced by one single instance of such a graph.
  Under CH, however, the class of $(\aleph_0,\aleph_1)$-graphs contains
minor-incomparable elements, namely graphs of binary type, and
$\mathcal{U}$-indivisible graphs. Assuming CH, Diestel and Leader asked whether
every $(\aleph_0,\aleph_1)$-graph has an $(\aleph_0,\aleph_1)$-minor that is
either indivisible or of binary type, and whether any two
$\mathcal{U}$-indivisible graphs are necessarily minors of each other. For both
questions, we construct examples showing that the answer is in the negative.


title:
CNSMO: A Network Services Manager/Orchestrator Tool for Cloud Federated
  Environments

abstract:
  Application service providers (ASPs) now develop, deploy, and maintain
complex computing platforms within multiple cloud infrastructures to improve
resilience, responsiveness and elasticity of their applications. On the other
hand, complex applications have little control and visibility over network
resources, and need to use low-level hacks to extract network properties and
prioritize traffic. This biased view, limits tenants flexibility while
deploying their applications and prevents them from implementing part of the
application logic in the network. In this paper, we propose the CNSMO (CYCLONE
Network Services Manager/Orchestrator) tool to bring the innovation at
federated cloud environments by bridging these network service capabilities to
cloud based services as part of the overall CYCLONE solution. The integration
of networking aspects with purely federated clouds, will allow users to request
specific infrastructures and manage their dedicated set of coordinated network
and IT resources in an easy and transparent way while operating dynamic
deployments of distributed applications.


title:
Classifying and sorting cluttered piles of unknown objects with robots:
  a learning approach

abstract:
  We consider the problem of sorting a densely cluttered pile of unknown
objects using a robot. This yet unsolved problem is relevant in the robotic
waste sorting business.
  By extending previous active learning approaches to grasping, we show a
system that learns the task autonomously. Instead of predicting just whether a
grasp succeeds, we predict the classes of the objects that end up being picked
and thrown onto the target conveyor. Segmenting and identifying objects from
the uncluttered target conveyor, as opposed to the working area, is easier due
to the added structure since the thrown objects will be the only ones present.
  Instead of trying to segment or otherwise understand the cluttered working
area in any way, we simply allow the controller to learn a mapping from an RGBD
image in the neighborhood of the grasp to a predicted result---all segmentation
etc. in the working area is implicit in the learned function. The grasp
selection operates in two stages: The first stage is hardcoded and outputs a
distribution of possible grasps that sometimes succeed. The second stage uses a
purely learned criterion to choose the grasp to make from the proposal
distribution created by the first stage.
  In an experiment, the system quickly learned to make good pickups and predict
correctly, in advance, which class of object it was going to pick up and was
able to sort the objects from a densely cluttered pile by color.


title: Two-Time-Slot Bidirectional Relaying in Molecular Communication

abstract:
  In this paper, we study the bidirectional/two-way relaying of molecular
communication and propose a relaying scheme with two time slots. Compared to
the four-time-slot and three-time-slot schemes, the proposed two-time-slot
scheme improves the throughput by a significant extent by allowing the end
nodes to transmit simultaneously at the very first time slot. In contrast to
the existing techniques, the proposed scheme employs a homogeneous molecular
communication for bidirectional relaying where all the nodes (i.e., end nodes
and relay node) are allowed to operate on the same type of molecule instead of
utilizing different types of molecule for different nodes. As a result, this
proposal of homogeneous molecular relaying remarkably improves the resource
reuse capability. This paper generically characterizes the transmission and
detection strategies of the proposed scheme. Moreover, we derive the analytical
bit error probabilities for the multiple access and broadcast phases and
present the end-to-end bit error probability of the proposed scheme. It's
noteworthy that we take it into account the effect of molecular interference in
the theoretical derivations. Extensive simulation is carried out, and it is
shown that simulation results match very well with the derived theoretical
analysis.


title:
A mass conservative scheme for fluid-structure interaction problems by
  the staggered discontinuous Galerkin method

abstract:
  In this paper, we develop a new mass conservative numerical scheme for the
simulations of a class of fluid-structure interaction problems. We will use the
immersed boundary method to model the fluid-structure interaction, while the
fluid flow is governed by the incompressible Navier-Stokes equations. The
immersed boundary method is proven to be a successful scheme to model
fluid-structure interactions. To ensure mass conservation, we will use the
staggered discontinuous Galerkin method to discretize the incompressible
Navier-Stokes equations. The staggered discontinuous Galerkin method is able to
preserve the skew-symmetry of the convection term. In addition, by using a
local postprocessing technique, the weakly divergence free velocity can be used
to compute a new postprocessed velocity, which is exactly divergence free and
has a superconvergence property. This strongly divergence free velocity field
is the key to the mass conservation. Furthermore, energy stability is improved
by the skew-symmetric discretization of the convection term. We will present
several numerical results to show the performance of the method.


title:
Comment on "Alternative interpretation of the recent experimental
  results of angle-resolved photoemission spectroscopy on GaMnAs [Sci. Rep. 6,
  27266 (2016)]" by M. Kobayashi et al., arXiv:1608.07718

abstract:
  Recently, Kobayashi et al. (arXiv:1608.07718; ref. 1) have proposed an
alternative interpretation of our angle-resolved photoemission spectroscopy
(ARPES) results for the dilute ferromagnetic semiconductor (Ga,Mn)As. They
claim that our ARPES data [Sci. Rep. 6, 27266 (2016); ref. 2] can be explained
by locating the Fermi level EF above the valence-band top, supporting the
impurity-band model of ferromagnetic (Ga,Mn)As. In this comment, we show that
the assignment of bands' positions in respect to EF by Kobayashi et al. is not
consistent with our data. By comparing the ARPES result to band-structure
calculations, we demonstrate clearly that EF resides inside the valence band in
accordance with the p-d Zener model.


title: Finite field Kakeya and Nikodym sets in three dimensions

abstract:
  We give improved lower bounds on the size of Kakeya and Nikodym sets over
$\mathbb{F}_q^3$. We also propose a natural conjecture on the minimum number of
points in the union of a not-too-flat set of lines in $\mathbb{F}_q^3$, and
show that this conjecture implies an optimal bound on the size of a Nikodym
set.


title: Noncommutative probability of type D

abstract:
  We construct a deformed Fock space and a Brownian motion coming from Coxeter
groups of type D. The construction is analogous to that of the $q$-Fock space
(of type A) and the $(\alpha,q)$-Fock space (of type B).


title:
Nonconservative extension of Keplerian integrals and a new class of
  integrable system

abstract:
  The invariance of the Lagrangian under time translations and rotations in
Kepler's problem yields the conservation laws related to the energy and angular
momentum. Noether's theorem reveals that these same symmetries furnish
generalized forms of the first integrals in a special nonconservative case,
which approximates various physical models. The system is perturbed by a
biparametric acceleration with components along the tangential and normal
directions. A similarity transformation reduces the biparametric disturbance to
a simpler uniparametric forcing along the velocity vector. The solvability
conditions of this new problem are discussed, and closed-form solutions for the
integrable cases are provided. Thanks to the conservation of a generalized
energy, the orbits are classified as elliptic, parabolic, and hyperbolic.
Keplerian orbits appear naturally as particular solutions to the problem. After
characterizing the orbits independently, a unified form of the solution is
built based on the Weierstrass elliptic functions. The new trajectories involve
fundamental curves such as cardioids and logarithmic, sinusoidal, and Cotes'
spirals. These orbits can represent the motion of particles perturbed by solar
radiation pressure, of spacecraft with continuous thrust propulsion, and some
instances of Schwarzschild geodesics. Finally, the problem is connected with
other known integrable systems in celestial mechanics.


abstract:
  This work presents PESMOC, Predictive Entropy Search for Multi-objective
Bayesian Optimization with Constraints, an information-based strategy for the
simultaneous optimization of multiple expensive-to-evaluate black-box functions
under the presence of several constraints. PESMOC can hence be used to solve a
wide range of optimization problems. Iteratively, PESMOC chooses an input
location on which to evaluate the objective functions and the constraints so as
to maximally reduce the entropy of the Pareto set of the corresponding
optimization problem. The constraints considered in PESMOC are assumed to have
similar properties to those of the objective functions in typical Bayesian
optimization problems. That is, they do not have a known expression (which
prevents gradient computation), their evaluation is considered to be very
expensive, and the resulting observations may be corrupted by noise. These
constraints arise in a plethora of expensive black-box optimization problems.
We carry out synthetic experiments to illustrate the effectiveness of PESMOC,
where we sample both the objectives and the constraints from a Gaussian process
prior. The results obtained show that PESMOC is able to provide better
recommendations with a smaller number of evaluations than a strategy based on
random search.


title:
Ground-state and magnetocaloric properties of a coupled spin-electron
  double-tetrahedral chain (exact study at the half filling)

abstract:
  Ground-state and magnetocaloric properties of a double-tetrahedral chain, in
which nodal lattice sites occupied by the localized Ising spins regularly
alternate with triangular clusters half filled with mobile electrons, are
exactly investigated by using the transfer-matrix method in combination with
the construction of the $N$th tensor power of the discrete Fourier
transformation. It is shown that the ground state of the model is formed by two
non-chiral phases with the zero residual entropy and two chiral phases with the
finite residual entropy $S = Nk_{\rm B}\ln 2$. Depending on the character of
the exchange interaction between the localized Ising spins and mobile
electrons, one or three magnetization plateaus can be observed in the
magnetization process. Their heights basically depend on the values of Land\'e
$g$-factors of the Ising spins and mobile electrons. It is also evidenced that
the system exhibits both the conventional and inverse magnetocaloric effect
depending on values of the applied magnetic field and temperature.


title: Multi-Cell Massive MIMO Performance with Double Scattering Channels

abstract:
  This paper investigates the spectral efficiency (SE) of multi-cell Massive
Multi-Input Multi-Output (MIMO) using different channel models. Prior works
have derived closed-form SE bounds and approximations for Gaussian distributed
channels, while we consider the double scattering model-a prime example of a
non-Gaussian channel for which it is intractable to obtain closed form SE
expressions. The channels are estimated using limited resources, which gives
rise to pilot contamination, and the estimates are used for linear detection
and to compute the SE numerically. Analytical and numerical examples are used
to describe the key behaviors of the double scattering models, which differ
from conventional Massive MIMO models. Finally, we provide multi-cell
simulation results that compare the double scattering model with uncorrelated
Rayleigh fading and explain under what conditions we can expect to achieve
similar SEs.


title:
New insights into the photochromic mechanism in oxygen-containing
  yttrium hydride thin films: an optical perspective

abstract:
  Oxygen-containing yttrium hydride thin films exhibit a photochromic behavior:
transparent thin films switch from a transparent state to a photodarkened state
after being illuminated with UV or blue light. This feature has attracted much
attention in recent years due to its potential applications in smart
fenestration or in any device in which a response to intense light radiation is
needed. However, the process responsible for the reversible change of the
optical properties upon illumination is still not well understood. The
objective of the present work is to shed some light on the photochromic
mechanism by using an optical approach. On this basis, the optical properties
of oxygen-containing yttrium hydride thin films have been studied by optical
spectrophotometry and ellipsometry before (transparent state) and after UV
illumination (dark state). According to the observed results, the photochromic
optical change of the films can be explained quantitatively by the gradual
growth, under illumination, of metallic phases within the initial wide-band gap
semiconducting lattice.


title:
Fast Abstracts and Student Forum Proceedings - EDCC 2016 - 12th European
  Dependable Computing Conference

abstract:
  Fast Abstracts are short presentations of work in progress or opinion pieces
and aim to serve as a rapid and flexible mechanism to (i) Report on current
work that may or may not be complete; (ii) Introduce new ideas to the
community; (iii) State positions on controversial issues or open problems. On
the other hand, the goal of the Student Forum is to encourage students to
attend EDCC and present their work, exchange ideas with researchers and
practitioners, and get early feedback on their research efforts.


title: Horizon supertranslation and degenerate black hole solutions

abstract:
  In this note we first review the degenerate vacua arising from the BMS
symmetries. According to the discussion in [1] one can define BMS-analogous
supertranslation and superrotation for spacetime with black hole in Gaussian
null coordinates. In the leading and subleading orders of near horizon
approximation, the infinitely degenerate black hole solutions are derived by
considering Einstein equations with or without cosmological constant, and they
are related to each other by the diffeomorphism generated by horizon
supertranslation. Higher order results and degenerate Rindler horizon solutions
also are given in appendices.


title: Inference for conditioned Galton-Watson trees from their Harris path

abstract:
  Tree-structured data naturally appear in various fields, particularly in
biology where plants and blood vessels may be described by trees, but also in
computer science because XML documents form a tree structure. This paper is
devoted to the estimation of the relative scale parameter of conditioned
Galton-Watson trees. New estimators are introduced and their consistency is
stated. A comparison is made with an existing approach of the literature. A
simulation study shows the good behavior of our procedure on finite-sample
sizes and from missing or noisy data. An application to the analysis of
revisions of Wikipedia articles is also considered through real data.


title: Zeros of linear twists of $L$-functions outside the critical strip

abstract:
  In this note we investigate the existence of zeros of linear twists of
$L$-functions outside of the critical strip. In particular, we show that the
Lerch zeta function $L(\lambda,\alpha,s)$ has infinitely many zeros for
$1<\sigma<1+\eta$, for any $\eta>0$, when $\lambda$ is irrational and $\alpha$
is rational. This settles the question on the existence of zeros of the Lerch
zeta functions for $\sigma>1$.


title:
Hydrodynamic Modeling of Accretion Impacts in Classical T Tauri Stars:
  Radiative Heating of the Pre-shock Plasma

abstract:
  Context. It is generally accepted that, in Classical T Tauri Stars, the
plasma from the circumstellar disc accretes onto the stellar surface with free
fall velocity, and the impact generates a shock. The impact region is expected
to contribute to emission in different spectral bands; many studies have
confirmed that the X-rays arise from the post-shock plasma but, otherwise,
there are no studies in the literature investigating the origin of the observed
UV emission which is apparently correlated to accretion. Aims. We investigated
the effect of radiative heating of the infalling material by the post-shock
plasma at the base of the accretion stream with the aim to identify in which
region a significant part of the UV emission originates. Methods. We developed
a 1D hydrodynamic model describing the impact of an accretion stream onto the
stellar surface; the model takes into account the gravity, the radiative
cooling of an optically thin plasma, the thermal conduction, and the heating
due to absorption of X-ray radiation. The latter term represents the heating of
the infalling plasma due to the absorption of X-rays emitted from the
post-shock region. Results. We found that the radiative heating of the
pre-shock plasma plays a non-negligible role in the accretion phenomenon. In
particular, the dense and cold plasma of the pre-shock accretion column is
gradually heated up to few $10^5$\;K due to irradiation of X-rays arising from
the shocked plasma at the impact region. This heating mechanism does not affect
significantly the dynamics of the post-shock plasma. On the other hand, a
region of radiatively heated gas (that we consider a precursor) forms in the
unshocked accretion column and contributes significantly to UV emission. Our
model naturally reproduces the luminosity of UV emission lines correlated to
accretion and shows that most of the UV emission originates from the precursor.


title: OH+ and H2O+ absorption toward PKS1830-211

abstract:
  We report the detection of OH+ and H2O+ in the z=0.89 absorber toward the
lensed quasar PKS1830-211. The abundance ratio of OH+ and H2O+ is used to
quantify the molecular hydrogen fraction (fH2) and the cosmic-ray ionization
rate of atomic hydrogen (zH) along two lines of sight, located at ~2 kpc and ~4
kpc to either side of the absorber's center. The molecular fraction decreases
outwards, from ~0.04 to ~0.02, comparable to values measured in the Milky Way
at similar galactocentric radii. For zH, we find values of ~2x10^-14 s^-1 and
~3x10^-15 s^-1, respectively, which are slightly higher than in the Milky Way
at comparable galactocentric radii, possibly due to a higher average star
formation activity in the z=0.89 absorber. The ALMA observations of OH+, H2O+,
and other hydrides toward PKS1830-211 reveal the multi-phase composition of the
absorbing gas. Taking the column density ratios along the southwest and
northeast lines of sight as a proxy of molecular fraction, we classify the
species ArH+, OH+, H2Cl+, H2O+, CH, and HF as tracing gases increasingly more
molecular. Incidentally, our data allow us to improve the accuracy of H2O+ rest
frequencies and thus refine the spectroscopic parameters.


title:
Computation of isotopisms of algebras over finite fields by means of
  graph invariants

abstract:
  In this paper we define a pair of faithful functors that map isomorphic and
isotopic finite-dimensional algebras over finite fields to isomorphic graphs.
These functors reduce the cost of computation that is usually required to
determine whether two algebras are isomorphic. In order to illustrate their
efficiency, we determine explicitly the classification of two- and
three-dimensional partial quasigroup rings.


title:
Existence results of totally real immersions and embeddings into
  $\mathbb{C}^N$

abstract:
  We prove that the existence of totally real immersions of manifolds is a
closed property under cut-and-paste constructions along submanifolds including
connected sums. We study the existence of totally real embeddings for simply
connected 5-manifolds and orientable 6-manifolds and determine the
diffeomorphism and homotopy types. We show that the fundamental group is not an
obstruction for the existence of a totally real embedding for high-dimensional
manifolds in contrast with the situation in dimension four.


title:
Remarks on an elliptic problem arising in weighted energy estimates for
  wave equations with space-dependent damping term in an exterior domain

abstract:
  This paper is concerned with weighted energy estimates and diffusion
phenomena for the initial-boundary problem of the wave equation with
space-dependent damping term in an exterior domain. In this analysis, an
elliptic problem was introduced by Todorova and Yordanov. This attempt was
quite useful when the coefficient of the damping term is radially symmetric. In
this paper, by modifying their elliptic problem, we establish weighted energy
estimates and diffusion phenomena even when the coefficient of the damping term
is not radially symmetric.


title: A Deep Multi-Level Network for Saliency Prediction

abstract:
  This paper presents a novel deep architecture for saliency prediction.
Current state of the art models for saliency prediction employ Fully
Convolutional networks that perform a non-linear combination of features
extracted from the last convolutional layer to predict saliency maps. We
propose an architecture which, instead, combines features extracted at
different levels of a Convolutional Neural Network (CNN). Our model is composed
of three main blocks: a feature extraction CNN, a feature encoding network,
that weights low and high level feature maps, and a prior learning network. We
compare our solution with state of the art saliency models on two public
benchmarks datasets. Results show that our model outperforms under all
evaluation metrics on the SALICON dataset, which is currently the largest
public dataset for saliency prediction, and achieves competitive results on the
MIT300 benchmark.


title: Anderson localization of ultracold atoms: Where is the mobility edge?

abstract:
  Recent experiments on non-interacting ultra-cold atoms in correlated disorder
have yielded conflicting results regarding the so-called mobility edge, i.e.
the energy threshold separating Anderson localized from diffusive states. At
the same time, there are theoretical indications that the experimental data
overestimate the position of this critical energy, sometimes by a large amount.
The non-trivial effect of anisotropy in the spatial correlations of
experimental speckle potentials have been put forward as a possible cause for
such discrepancy. Using extensive numerical simulations we show that the effect
of anisotropy alone is not sufficient to explain the experimental data. In
particular, we find that, for not-too-strong anisotropy, realistic disorder
configurations are essentially identical to the isotropic case, modulo a simple
rescaling of the energies.


title:
Coupon collector's probabilities and generating function: analytic
  approach

abstract:
  Despite the coupon collector's problem has simple probabilistic solution
using inclusion/exclusion principle \cite{PolyaUrn}, starting from a particular
type of recurrence differential equation it is used an analytic approach to
recover explicit probabilities and generating function. Note that this kind of
recurrence differential equations often appear in Polya Urn context
\cite{PolyaUrn}.


title:
Functional central limit theorems for the Nelson-Aalen and Kaplan-Meier
  estimators for dependent stationary data

abstract:
  We derive process limit distribution results for the Nelson-Aalen estimator
of a hasard function and for the Kaplan-Meier estimator of a distribution
function, under different dependence assumptions. The data are assumed to be
right censored observations of a stationary time series. We treat weakly
dependent as well as long range dependent data, and allow for qualitative
differences in the dependence for the censoring times versus the time of
interest


title: Dynamic Path Contraction for Distributed, Dynamic Dataflow Languages

abstract:
  We present a work in progress report on applying deforestation to
distributed, dynamic dataflow programming models. We propose a novel algorithm,
dynamic path contraction, that applies and reverses optimizations to a
distributed dataflow application as the program executes. With this algorithm,
data and control flow is tracked by the runtime system used to identify
potential optimizations as the system is running. We demonstrate and present
preliminary results regarding this technique on an actor-based distributed
programming model, Lasp, implemented on the Erlang virtual machine.


title:
Modeling the gamma-ray emission in the Galactic Center with a fading
  cosmic-ray accelerator

abstract:
  Recent HESS observations of the ~200 pc scale diffuse gamma-ray emission from
the central molecular zone (CMZ) suggest the presence of a PeV cosmic-ray
accelerator (PeVatron) located in the inner 10 pc region of the Galactic
Center. Interestingly, the gamma-ray spectrum of the point-like source (HESS
J1745-290) in the Galactic Center shows a cutoff at ~10 TeV, implying a cutoff
around 100 TeV in the cosmic-ray proton spectrum. Here we propose that the
gamma-ray emission from the inner and the outer regions may be explained
self-consistently by run-away protons from a single, yet fading accelerator. In
this model, gamma rays from the CMZ region are produced by protons injected in
the past, while gamma rays from the inner region are produced by protons
injected more recently. We suggest that the blast wave formed in a tidal
disruption event (TDE) caused by the supermassive black hole (Sgr A*) could
serve as such a fading accelerator. With typical parameters of the TDE blast
wave, gamma-ray spectra of both the CMZ region and HESS J1745-290 can be
reproduced simultaneously. Meanwhile, we find that the cosmic-ray energy
density profile in the CMZ region may also be reproduced in the fading
accelerator model when appropriate combinations of the particle injection
history and the diffusion coefficient of cosmic rays are adopted.


title: Toward Crowdsourced User Studies for Software Evaluation

abstract:
  This work-in-progress paper describes a vision, i.e., that of fast and
reliable software user experience studies conducted with the help from the
crowd. Commonly, user studies are controlled in-lab activities that require the
instruction, monitoring, interviewing and compensation of a number of
participants that are typically hard to recruit. The goal of this work is to
study which user study methods can instead be crowdsourced to generic audiences
to enable the conduct of user studies without the need for expensive lab
experiments. The challenge is understanding how to conduct crowdsourced studies
without giving up too many of the guarantees in-lab settings are able to
provide.


title: The triple system AT Mic AB + AU Mic in the beta Pictoris Association

abstract:
  Equal-mass stars in young open clusters and loose associations exhibit a wide
spread of rotation periods, which likely originates from differences in the
initial rotation periods and in the primordial disc lifetimes. We want to
explore if the gravitational effects by nearby companions may play an
additional role in producing the observed rotation period spread. We measure
the photometric rotation periods of components of multiple stellar systems and
look for correlations of the period differences among the components to their
reciprocal distances. In this paper, we analysed the triple system AU Mic + AT
Mic A&B in the 25-Myr beta Pictoris Association. We have retrieved from the
literature the rotation period of AU Mic (P = 4.85d) and measured from
photometric archival data the rotation periods of both components of AT Mic (P
= 1.19d and P = 0.78d) for the first time. Moreover, we detected a high rate of
flare events from AT Mic. Whereas the distant component AU Mic has evolved
rotationally as a single star, the A and B components of AT Mic, separated by
about 27 AU, exhibit a rotation rate a factor 5 larger than AU Mic. Moreover,
the A and B components, despite have about equal mass, show a significant
difference (about 40%) between their rotation periods. A possible explanation
is that the gravitational forces between the A and B components of AT Mic (that
are a factor about 7.3 x 10^6 more intense than those between AU Mic and AT
Mic) have enhanced the dispersal of the AT Mic primordial disc, shortening its
lifetime and the disc-locking phase duration, making the component A and B of
AT Mic to rotate faster than the more distant AU Mic. We suspect that a
different level of magnetic activity between the A and B components of AT Mic
may be the additional parameter responsible for the difference between their
rotation periods.


title: FIGGS2: An HI survey of extremely faint irregular galaxies

abstract:
  We present the observations and first results from the FIGGS2 survey. FIGGS2
is an extension of the earlier Faint Irregular Galaxies GMRT survey (FIGGS)
towards faint luminosity end. The sample consists of 20 galaxies of which 15
were detected in HI 21cm line using the Giant Meter-wave Radio Telescope
(GMRT). The median blue band magnitude of our sample is ~ -11.6, which is more
than one magnitude fainter than earlier FIGGS survey. From our GMRT
observations we find that, for many of our sample galaxies, the HI disks are
offset from their optical disks. The HI diameters of the FIGGS2 galaxies show a
tight correlation with their HI mass. The slope of the correlation is 2.08 +/-
0.20 similar to what is found for FIGGS galaxies. We also find that for almost
all galaxies, the HI disks are larger than the optical disks which is a common
trend for dwarf or spiral galaxies. The mean value of the ratio of HI to
optical diameter is ~ 1.54.


title:
A review on wave propagation modeling in band-gap metamaterials via
  enriched continuum models

abstract:
  In the present contribution we show that the relaxed micromorphic model is
the only non-local continuum model which is able to account for the description
of band-gaps in metamaterials for which the kinetic energy accounts separately
for micro and macro-motions without considering a micro-macro coupling.
Moreover, we show that when adding a gradient inertia term which indeed allows
for the description of the coupling of the vibrations of the microstructure to
the macroscopic motion of the unit cell, other enriched continuum models of the
micromorphic type may allow the description of the onset of band-gaps.
Nevertheless, the relaxed micromorphic model proves to be yet the most
effective enriched continuum model which is able to describe multiple band-gaps
in non-local metamaterials.


title: Analytical aspects of spatially adapted total variation regularisation

abstract:
  In this paper we study the structure of solutions of the one dimensional
weighted total variation regularisation problem, motivated by its application
in signal recovery tasks. We study in depth the relationship between the weight
function and the creation of new discontinuities in the solution. A partial
semigroup property relating the weight function and the solution is shown and
analytic solutions for simply data functions are computed. We prove that the
weighted total variation minimisation problem is well-posed even in the case of
vanishing weight function, despite the lack of coercivity. This is based on the
fact that the total variation of the solution is bounded by the total variation
of the data, a result that it also shown here. Finally the relationship to the
corresponding weighted fidelity problem is explored, showing that the two
problems can produce completely different solutions even for very simple data
functions.


title:
Valley Polarization by Spin Injection in a Light-Emitting van der Waals
  Heterojunction

abstract:
  The band structure of transition metal dichalcogenides (TMDCs) with valence
band edges at different locations in the momentum space could be harnessed to
build devices that operate relying on the valley degree of freedom. To realize
such valleytronic devices, it is necessary to control and manipulate the charge
density in these valleys, resulting in valley polarization. While this has been
demonstrated using optical excitation, generation of valley polarization in
electronic devices without optical excitation remains difficult. Here, we
demonstrate spin injection from a ferromagnetic electrode into a heterojunction
based on monolayers of WSe2 and MoS2 and lateral transport of spin-polarized
holes within the WSe2 layer. The resulting valley polarization leads to
circularly polarized light emission which can be tuned using an external
magnetic field. This demonstration of spin injection and magnetoelectronic
control over valley polarization provides a new opportunity for realizing
combined spin and valleytronic devices based on spin-valley locking in
semiconducting TMDCs.


title:
Sensitive linear response of an electron-hole superfluid in a periodic
  potential

abstract:
  We consider excitons in a two-dimensional periodic potential and study the
linear response of the excitonic superfluid to an electromagnetic wave at low
and high densities. It turns out that the static structure factor for small
wavevectors is very sensitive to a change of density and temperature. It is a
consequence of the fact that thermal fluctuations play a crucial role at small
wavevectors, since exchanging the order of the two limits, zero temperature and
vanishing wavevector, leads to different results for the structure factor. This
effect could be used for high accuracy measurements in the superfluid exciton
phase, which might be realized by a gated electron-hole gas. The transition of
the exciton system from the superfluid state to a non-superfluid state and its
manifestation by light scattering are discussed.


title:
The role of the Fermi level pinning in gate tunable
  graphene-semiconductor junctions

abstract:
  Graphene based transistors relying on a conventional structure cannot switch
properly because of the absence of an energy gap in graphene. To overcome this
limitation, a barristor device was proposed, whose operation is based on the
modulation of the graphene-semiconductor (GS) Schottky barrier by means of a
top gate, and demonstrating an ON-OFF current ratio up to $10^5$. Such a large
number is likely due to the realization of an ultra clean interface with
virtually no interface trapped charge. However, it is indeed technologically
relevant to know the impact that the interface trapped charges might have on
the barristor's electrical properties. We have developed a physics based model
of the gate tunable GS heterostructure where non-idealities such as Fermi Level
Pinning (FLP) and a "bias dependent barrier lowering effect" has been
considered. Using the model we have made a comprehensive study of the
barristor's expected digital performance.


title: Subset Sum Problems With Digraph Constraints

abstract:
  We introduce and study four optimization problems that generalize the
well-known subset sum problem. Given a node-weighted digraph, select a subset
of vertices whose total weight does not exceed a given budget. Some additional
constraints need to be satisfied. The (weak resp.) digraph constraint imposes
that if (all incoming nodes of resp.) a node $x$ belongs to the solution, then
the latter comprises all its outgoing nodes (node $x$ itself resp.). The
maximality constraint ensures that a solution cannot be extended without
violating the budget or the (weak) digraph constraint. We study the complexity
of these problems and we present some approximation results according to the
type of digraph given in input, e.g. directed acyclic graphs and oriented
trees.
  Key words. Subset Sum, Maximal problems, digraph constraints, complexity,
directed acyclic graphs, oriented trees, PTAS.


title: Astronomical Data Fusion Tool Based on PostgreSQL

abstract:
  With the application of advanced astronomical technologies, equipments and
methods all over the world, astronomy covers from radio, infrared, visible
light, ultraviolet, X-ray and gamma ray band, and enters into the era of full
wavelength astronomy. How to effectively integrate data from different ground-
and space-based observation equipments, different observers, different bands,
different observation time, requires the data fusion technology. In this paper
we introduce the cross-match tool that is developed by the Python language and
based on the PostgreSQL database and uses Q3C as the core index, facilitating
the cross-match work of massive astronomical data. It provides four different
cross-match functions, namely: I) cross-match of custom error range; II)
cross-match of catalog error; III) cross-match based on the elliptic error
range; IV) cross-match of the nearest algorithm. The cross-match result set
provides good foundation for subsequent data mining and statistics based on
multiwavelength data. The most advantage of this tool is a user-oriented tool
applied locally by users. By means of this tool, users may easily create their
own databases, manage their own data and cross-match databases according to
their requirements. In addition, this tool is also able to transfer data from
one database into another database. More importantly, the tool is easy to get
started and used by astronomers without writing any code.


title: Multipolar Hardy inequalities on Riemannian manifolds

abstract:
  We prove multipolar Hardy inequalities on complete Riemannian manifolds,
providing various curved counterparts of some Euclidean multipolar inequalities
due to Cazacu and Zuazua [Improved multipolar Hardy inequalities, 2013]. We
notice that our inequalities deeply depend on the curvature, providing
(quantitative) information about the deflection from the flat case. By using
these inequalities together with variational methods and group-theoretical
arguments, we also establish non-existence, existence and multiplicity results
for certain Schr\"odinger-type problems involving the Laplace-Beltrami operator
and bipolar potentials on Cartan-Hadamard manifolds and on the open upper
hemisphere, respectively.


title:
On the linearization of nonlinear supersymmetry based on the commutator
  algebra

abstract:
  We discuss a linearization procedure of nonlinear supersymmetry (NLSUSY)
based on the closure of the commutator algebra for variations of functionals of
Nambu-Goldstone fermions and their derivative terms under NLSUSY
transformations in Volkov-Akulov NLSUSY theory. In the case of a set of bosonic
and fermionic functionals, which leads to (massless) vector linear
supermultiplets, we explicitly show that general linear SUSY transformations of
basic components defined from those functionals are uniquely determined by
examining the commutation relation in the NLSUSY theory.


title: Mean-Lagrangian formalism and covariance of fluid turbulence

abstract:
  Mean-field-based Lagrangian framework is developed for the fluid turbulence
theory. The space- time vector flow is naturally introduced from the mean
velocity, which provides the Lagrangian picture based on the mean field in
totally equivalent manner to that of the instantaneous field. The proposed
framework is applied, on one hand, to one-point closure model, yielding an
objective expression of the turbulence visco-elastic effect. Application to
two-point closure, on the other hand, is also discussed, where natural
extension of known Lagrangian correlation is discovered on the basis of
extended covariance group.


title: Approaching bilinear multipliers via a functional calculus

abstract:
  We propose a framework for bilinear multiplier operators defined via the
(bivariate) spectral theorem. Under this framework we prove Coifman-Meyer type
multiplier theorems and fractional Leibniz rules. Our theory applies to
bilinear multipliers associated with the discrete Laplacian on $\mathbb{Z}^d,$
general bi-radial bilinear Dunkl multipliers, and to bilinear multipliers
associated with the Jacobi expansions.


title:
Uniform Global Attractors for Non-Autonomous Dissipative Dynamical
  Systems

abstract:
  In this paper we consider sufficient conditions for the existence of uniform
compact global attractor for non-autonomous dynamical systems in special
classes of infinite-dimensional phase spaces. The obtained generalizations
allow us to avoid the restrictive compactness assumptions on the space of
shifts of non-autonomous terms in particular evolution problems. The results
are applied to several evolution inclusions.


title: Structure of charmed baryons studied by pionic decays

abstract:
  We investigate the decays of the charmed baryons aiming at the systematic
understanding of hadron internal structures based on the quark model by paying
attention to heavy quark symmetry. We evaluate the decay widths from the one
pion emission for the known excited states, \Lambda_c^*(2595),
\Lambda_c^*(2625), \Lambda_c^*(2765), \Lambda_c^*(2880) and \Lambda_c^*(2940),
as well as for the ground states \Sigma_c(2455) and \Sigma_c^*(2520). The decay
properties of the lower excited charmed baryons are well explained, and several
important predictions for higher excited baryons are given. We find that the
axial-vector type coupling of the pion to the light quarks is essential, which
is expected from chiral symmetry, to reproduce the decay widths especially of
the low lying \Lambda_c^* baryons. We emphasize the importance of the branching
ratios of \Gamma(\Sigma_c^*\pi)/\Gamma(\Sigma_c\pi) for the study of the nature
of higher excited \Lambda_c^* baryons.


title: Prometheus Induced Vorticity In Saturns F Ring

abstract:
  Saturns rings are known to show remarkable real time variability in their
structure. Many of which can be associated to interactions with nearby moons
and moonlets. Possibly the most interesting and dynamic place in the rings,
probably in the whole Solar System, is the F ring. A highly disrupted ring with
large asymmetries both radially and azimuthally. Numerically non zero
components to the curl of the velocity vector field (vorticity) in the
perturbed area of the F ring post encounter are witnessed, significantly above
the background vorticity. Within the perturbed area rich distributions of local
rotations is seen located in and around the channel edges. The gravitational
scattering of ring particles during the encounter causes a significant elevated
curl of the vector field above the background F ring vorticity for the first
1-3 orbital periods post encounter. After 3 orbital periods vorticity reverts
quite quickly to near background levels. This new found dynamical vortex life
of the ring will be of great interest to planet and planetesimals in
proto-planetary disks where vortices and turbulence are suspected of having a
significant role in their formation and migrations. Additionally, it is found
that the immediate channel edges created by the close passage of Prometheus
actually show high radial dispersions in the order ~20-50 cm/s, up to a maximum
of 1 m/s. This is much greater than the value required by Toomre for a disk to
be unstable to the growth of axisymmetric oscillations. However, an area a few
hundred km away from the edge shows a more promising location for the growth of
coherent objects.


title:
Forced canonical thermalization in a hadronic transport approach at high
  density

abstract:
  Hadronic transport approaches based on an effective solution of the
relativistic Boltzmann equation are widely applied for the dynamical
description of heavy ion reactions at low beam energies. At high densities, the
assumption of binary interactions often used in hadronic transport approaches
may not be applicable anymore. Therefore, we effectively simulate the
high-density regime using the local forced canonical thermalization. This
framework provides the opportunity to interpolate in a dynamical way between
two different limits of kinetic theory: the dilute gas approximation and the
ideal fluid case. This approach will be important for studies of the dynamical
evolution of heavy ion collisions at low and intermediate energies as
experimentally investigated at the beam energy scan program at RHIC, and in the
future at FAIR and NICA. On the other hand, this new way of modelling hot and
dense strongly-interacting matter might be relevant for small systems at high
energies (LHC and RHIC) as well.


title: GTApprox: surrogate modeling for industrial design

abstract:
  We describe GTApprox - a new tool for medium-scale surrogate modeling in
industrial design. Compared to existing software, GTApprox brings several
innovations: a few novel approximation algorithms, several advanced methods of
automated model selection, novel options in the form of hints. We demonstrate
the efficiency of GTApprox on a large collection of test problems. In addition,
we describe several applications of GTApprox to real engineering problems.


title:
Relating the spectrum of a matrix and a principal submatrix using
  adjugates and Schur complements

abstract:
  Let $\mathcal{M}$ be a square matrix over a commutative ring and let
$\mathcal{A}$ be a principal submatrix. We give relations between the
determinants of $\mathcal{M}$ and $\mathcal{A}$ based on an annihilating
polynomial for one of them. The intended application is the size reduction of
complex latent root problems, especially the reduction of ordinary eigenvalue
problems if a matrix or its principal submatrix have a low degree minimal
polynomial. An example is the spectrum of vertex perturbed strongly regular
graphs.


title: Quasi-Banach Valued Inequalities via the Helicoidal method

abstract:
  We extend the helicoidal method that we previously developed to the
quasi-Banach context, proving in this way multiple Banach and quasi-Banach
vector-valued inequalities for paraproducts $\Pi$ and for the bilinear Hilbert
transform $BHT$. As an immediate application, we obtain mixed norm estimates
for $\Pi \otimes \Pi$ in the whole range of Lebesgue exponents.
  One of the novelties in the quasi-Banach framework (that is, when $0<r<1$),
which we expect to be useful in other contexts as well, is the "linearization"
of the operator $ \left( \sum_k | T(f_k, g_k) |^r \right)^{1/r}$ by dualizing
its weak-$L^p$ quasinorms through $L^r$. Another important role is played by
the sharp evaluation of the operatorial norm $\| T_{I_0}(f \cdot \mathbf{1}_F,
g \cdot \mathbf{1}_G) \cdot \mathbf{1}_{H'}\|_r$, which is obtained by
dualizing the weak-$L^p$ quasinorms through $L^\tau$, with $\tau \leq r$. In
the Banach case, the linearization of the operator and the sharp estimates for
the localized operatorial norm can be both achieved through the classical
(generalized restricted type) $L^1$ dualization.


title: Reconfinement of highly magnetized jets: Implications for HST-1 in M87

abstract:
  Stationary features are occasionally observed in AGN jets. A notable example
is the HST-1 knot in M87. Such features are commonly interpreted as
re-confinement shocks in hydrodynamic jets or focusing nozzles in Poynting
jets. In this paper we compute the structure and Lorentz factor of a highly
magnetized jet confined by external pressure having a profile that flattens
abruptly at some radius. We find the development of strong oscillations upon
transition from the steeper to the flatter pressure profile medium. Analytic
formula is derived for the location of the nodes of these oscillations. We
apply the model to the M87 jet and show that if the jet remains magnetically
dominated up to sub-kpc scales, then focusing is expected. The location of the
HST-1 knot can be reconciled with recent measurements of the pressure profile
around the Bondi radius if the jet luminosity satisfies $L_j\simeq10^{43}$
erg/s. However, we find that magnetic domination at the collimation break
implies a Lorentz factor in excess of $10^2$, atypical to FRI sources. A much
lower value of the asymptotic Lorentz factor would require substantial loading
close to the black hole. In that case HST-1 may be associated with a
collimation nozzle of a hydrodynamic flow.


title: A model for pressurized hydrogen induced thin film blisters

abstract:
  We introduce a model for hydrogen induced blister formation in nanometer
thick thin films. The model assumes that molecular hydrogen gets trapped under
a circular blister cap causing it to deflect elastically outward until a stable
blister is formed. In the first part, the energy balance required for a stable
blister is calculated. From this model, the adhesion energy of the blister cap,
the internal pressure and the critical H-dose for blister formation can be
calculated. In the second part, the flux balance required for a blister to grow
to a stable size is calculated. The model is applied to blisters formed in a
Mo/Si multilayer after being exposed to hydrogen ions. From the model the
adhesion energy of the Mo/Si blister cap was calculated to be around 1.05 J/m2
with internal pressures in the range of 175-280 MPa. Based on the model a
minimum ion dose for the onset of blister formation was calculated to be d =
4.2*10^18 ions/cm2. From the flux balance equations the diffusion constant for
the Mo/Si blister cap was estimated to be D_H2 = (10+-1) *10^18 cm2/s.


title: Finite dimensional approximation properties of $C^{*}$-modules

abstract:
  We study nuclearity and exactness for module maps on $C^{*}$-algebras which
are $C^*$-module over another $C^*$-algebra with compatible actions and study
finite dimensional approximation properties of such $C^*$-modules. We prove
module versions of the results of Kirchberg and Choi-Effros. As a concrete
example we extend the finite dimensional approximation properties of reduced
$C^*$-algebras and von Neumann algebras on discrete groups to these operator
algebras on inverse semigroups with the module structure coming from the action
of the $C^*$-algebras on the subsemigroup of idempotents.


title: Coarsening dynamics of topological defects in thin Permalloy films

abstract:
  We study the dynamics of topological defects in the magnetic texture of
rectangular Permalloy thin film elements during relaxation from random
magnetization initial states. Our full micromagnetic simulations reveal complex
defect dynamics during relaxation towards the stable Landau closure domain
pattern, manifested as temporal power-law decay, with a system-size dependent
cut-off time, of various quantities. These include the energy density of the
system, and the number densities of the different kinds of topological defects
present in the system. The related power-law exponents assume non-trivial
values, and are found to be different for the different defect types. The
exponents are robust against a moderate increase in the Gilbert damping
constant and introduction of quenched structural disorder. We discuss details
of the processes allowed by conservation of the winding number of the defects,
underlying their complex coarsening dynamics.


title:
Detection of very high energy gamma-ray emission from the
  gravitationally-lensed blazar QSO B0218+357 with the MAGIC telescopes

abstract:
  Context. QSO B0218+357 is a gravitationally lensed blazar located at a
redshift of 0.944. The gravitational lensing splits the emitted radiation into
two components, spatially indistinguishable by gamma-ray instruments, but
separated by a 10-12 day delay. In July 2014, QSO B0218+357 experienced a
violent flare observed by the Fermi-LAT and followed by the MAGIC telescopes.
Aims. The spectral energy distribution of QSO B0218+357 can give information on
the energetics of z ~ 1 very high energy gamma- ray sources. Moreover the
gamma-ray emission can also be used as a probe of the extragalactic background
light at z ~ 1. Methods. MAGIC performed observations of QSO B0218+357 during
the expected arrival time of the delayed component of the emission. The MAGIC
and Fermi-LAT observations were accompanied by quasi-simultaneous optical data
from the KVA telescope and X-ray observations by Swift-XRT. We construct a
multiwavelength spectral energy distribution of QSO B0218+357 and use it to
model the source. The GeV and sub-TeV data, obtained by Fermi-LAT and MAGIC,
are used to set constraints on the extragalactic background light. Results.
Very high energy gamma-ray emission was detected from the direction of QSO
B0218+357 by the MAGIC telescopes during the expected time of arrival of the
trailing component of the flare, making it the farthest very high energy
gamma-ray sources detected to date. The observed emission spans the energy
range from 65 to 175 GeV. The combined MAGIC and Fermi-LAT spectral energy
distribution of QSO B0218+357 is consistent with current extragalactic
background light models. The broad band emission can be modeled in the
framework of a two zone external Compton scenario, where the GeV emission comes
from an emission region in the jet, located outside the broad line region.


title:
Microwave-Induced Oscillations in the Magnetocapacitance: Direct
  Evidence for Non-equilibrium Occupation of Electronic States

abstract:
  In a two-dimensional electron system, microwave radiation may induce giant
resistance oscillations. Their origin has been debated controversially and
numerous mechanisms based on very different physical phenomena have been
invoked. However none of them have been unambiguously experimentally
identified, since they produce similar effects in transport studies. The
capacitance of a two-subband system is sensitive to a redistribution of
electrons over energy states, since it entails a shift of the electron charge
perpendicular to the plane. In such a system microwave induced
magnetocapacitance oscillations have been observed. They can only be accounted
for by an electron distribution function oscillating with energy due to Landau
quantization, one of the quantum mechanisms proposed for the resistance
oscillations.


title:
$C^*$-simplicity and Ozawa conjecture for groupoid $C^*$-algebras, part
  I: injective envelopes

abstract:
  This paper studies injective envelopes of groupoid dynamical systems and the
corresponding boundaries. Analogue to the group case, we associate a bundle of
compact Hausdorff spaces to any (discrete) groupoid (the Hamana boundary of the
groupoid). We study bundles of compact topological spaces equipped with an
action of a groupoid. We show that any groupoid has a minimal boundary (the
Furstenberg boundary of the groupoid). We prove that the Hamana and Furstenberg
boundaries are the same, for (discrete) groupoids. We find the relation between
the reduced crossed product of the $\G$-injective envelop of a groupoid
dynamical system and the injective envelope of the reduced crossed product of
the original system.


title:
Quantum-State Controlled Penning Ionization Reactions between Ultracold
  Alkali and Metastable Helium Atoms

abstract:
  In an ultracold, optically trapped mixture of $^{87}$Rb and metastable
triplet $^4$He atoms we have studied trap loss for different spin-state
combinations, for which interspecies Penning ionization is the main two-body
loss process. We observe long trapping lifetimes for the purely quartet
spin-state combination, indicating strong suppression of Penning ionization
loss by at least two orders of magnitude. For the other spin-mixtures we
observe short lifetimes that depend linearly on the doublet character of the
entrance channel. We compare the extracted loss rate coefficient with recent
predictions of multichannel quantum-defect theory for reactive collisions
involving a strong exothermic loss channel and find near-universal loss for
doublet scattering. Our work demonstrates control of reactive collisions by
internal atomic state preparation.


title: Multipolar interference effects in nanophotonics

abstract:
  Scattering of electromagnetic waves by an arbitrary nanoscale object can be
characterized by a multipole decomposition of the electromagnetic field that
allows to describe the scattering intensity and radiation pattern through
interferences of dominating excited multipole modes. In modern nanophotonics,
both generation and interference of multipole modes start to play an
indispensable role, and they enable nanoscale manipulation of light with many
related applications. Here we review the multipolar interference effects in
metallic, metal-dielectric, and dielectric nanostructures, and suggest a
comprehensive view on many phenomena involving the interferences of electric,
magnetic and toroidal multipoles, which drive a number of recently discussed
effects in nanophotonics such as unidirectional scattering, effective optical
antiferromagnetism, generalized Kerker scattering with controlled angular
patterns, generalized Brewster angle, and nonradiating optical anapoles. We
further discuss other types of possible multipolar interference effects not yet
exploited in literature and envisage the prospect of achieving more flexible
and advanced nanoscale control of light relying on the concepts of multipolar
interference through full phase and amplitude engineering.


title: A max-cut approach to heterogeneity in cryo-electron microscopy

abstract:
  The field of cryo-electron microscopy has made astounding advancements in the
past few years, mainly due to advancements in electron detectors' technology.
Yet, one of the key open challenges of the field remains the processing of
heterogeneous data sets, produced from samples containing particles at several
different conformational states. For such data sets, the algorithms must
include some classification procedure to identify homogeneous groups within the
data, so that the images in each group correspond to the same underlying
structure. The fundamental importance of the heterogeneity problem in
cryo-electron microscopy has drawn many research efforts, and resulted in
significant progress in classification algorithms for heterogeneous data sets.
While these algorithms are extremely useful and effective in practice, they
lack rigorous mathematical analysis and performance guarantees.
  In this paper, we attempt to make the first steps towards rigorous
mathematical analysis of the heterogeneity problem in cryo-electron microscopy.
To that end, we present an algorithm for processing heterogeneous data sets,
and prove accuracy and stability bounds for it. We also suggest an extension of
this algorithm that combines the classification and reconstruction steps. We
demonstrate it on simulated data, and compare its performance to the
state-of-the-art algorithm in RELION.


title:
Performance analysis of a non-beacon enabled IEEE 802.15.4 network with
  retransmission and ACK mode

abstract:
  The aim of our work is to evaluate the performance of non-beacon IEEE
802.15.4 networks with acknowledgement (ACK) mode and retransmission limits in
a finer time unit. Moreover, we predict network performance parameters using
backpropagation artificial neural networks (BP-ANNs) with respect to a given
quality of service for real-world applications. Therefore, our proposed methods
can assist the deployment of a star network with its performance specified in a
more practical way. First, the discrete time Markov chain model and M/M/1/k
queue are used to describe the full unslotted carrier sense multiple access
with collision avoidance (CSMA/CA) algorithm in a non-beacon network.
Considering MAC buffer size, unsaturated traffic, and saturated traffic, we
build three analytical models to derive eight important performance metrics,
e.g., throughput, delay, and reliability. In addition, extensive simulation
results show the accuracy of the analytical models in throughput and
reliability. Finally, we use the analytical data to train the BP-ANNs models to
predict the key parameters such as node number and delay. All results from the
simulation data used to test the BP-ANNs show the accuracy these models. Thus,
these methods and results can be used to deploy star networks in application
environments.


title: Monadic second-order properties of very sparse random graphs

abstract:
  We study asymptotical probabilities of first order and monadic second order
properties of Erdos-Renyi random graph G(n,n^{-a}). The random graph obeys FO
(MSO) zero-one k-law if for any first order (monadic second order) formulae it
is true for G(n,n^{-a}) with probability tending to 0 or to 1. Zero-one k-laws
are well studied only for the first order language and a < 1. We obtain new
zero-one k-laws (both for first order and monadic second order languages) when
a > 1. Proofs of these results are based on the existed study of first order
equivalence classes and our study of monadic second order equivalence classes.
The respective results are of interest by themselves.


title: Deep Retinal Image Understanding

abstract:
  This paper presents Deep Retinal Image Understanding (DRIU), a unified
framework of retinal image analysis that provides both retinal vessel and optic
disc segmentation. We make use of deep Convolutional Neural Networks (CNNs),
which have proven revolutionary in other fields of computer vision such as
object detection and image classification, and we bring their power to the
study of eye fundus images. DRIU uses a base network architecture on which two
set of specialized layers are trained to solve both the retinal vessel and
optic disc segmentation. We present experimental validation, both qualitative
and quantitative, in four public datasets for these tasks. In all of them, DRIU
presents super-human performance, that is, it shows results more consistent
with a gold standard than a second human annotator used as control.


title: Sparse recovery in Wigner-D basis expansion

abstract:
  We are concerned with the recovery of $s-$sparse Wigner-D expansions in terms
of $N$ Wigner-D functions. Considered as a generalization of spherical
harmonics, Wigner-D functions are eigenfunctions of Laplace-Beltrami operator
and form an orthonormal system. However, since they are not uniformly bounded,
the existing results on BOS do not apply. Using previously introduced
preconditioning technique, a new orthonormal and bounded system is obtained for
which RIP property can be established. We show that the number of sufficient
samples for sparse recovery scales with ${N}^{1/6} \,s\, \log^3(s) \,\log(N)$.
The phase transition diagram for this problem is also presented. We will also
discuss the application of our results in the spherical near-field antenna
measurement.


title:
The Accuracy of Mean-Field Approximation for
  Susceptible-Infected-Susceptible Epidemic Spreading

abstract:
  The epidemic spreading has been studied for years by applying the mean-field
approach in both homogeneous case, where each node may get infected by an
infected neighbor with the same rate, and heterogeneous case, where the
infection rates between different pairs of nodes are different. Researchers
have discussed whether the mean-field approaches could accurately describe the
epidemic spreading for the homogeneous cases but not for the heterogeneous
cases. In this paper, we explore under what conditions the mean-field approach
could perform well when the infection rates are heterogeneous. In particular,
we employ the Susceptible-Infected-Susceptible (SIS) model and compare the
average fraction of infected nodes in the metastable state obtained by the
continuous-time simulation and the mean-field approximation. We concentrate on
an individual-based mean-field approximation called the N-intertwined Mean
Field Approximation (NIMFA), which is an advanced approach considered the
underlying network topology. Moreover, we consider not only the independent and
identically distributed (i.i.d.) infection rate but also the infection rate
correlated with the degree of the two end nodes. We conclude that NIMFA is
generally more accurate when the prevalence of the epidemic is higher. Given
the same effective infection rate, NIMFA is less accurate when the variance of
the i.i.d.\ infection rate or the correlation between the infection rate and
the nodal degree leads to a lower prevalence. Moreover, given the same actual
prevalence, NIMFA performs better in the cases: 1) when the variance of the
i.i.d.\ infection rates is smaller (while the average is unchanged); 2) when
the correlation between the infection rate and the nodal degree is positive.


title: Properties of Supersonic Evershed Downflows

abstract:
  We study supersonic Evershed downflows in a sunspot penumbra by means of high
spatial resolution spectropolarimetric data acquired in the Fe I 617.3 nm line
with the CRISP instrument at the Swedish 1-m Solar Telescope. Physical
observables, such as Dopplergrams calculated from line bisectors and Stokes V
zero-crossing wavelengths, and Stokes V maps in the far red wing, are used to
find regions where supersonic Evershed downflows may exist. We retrieve the LOS
velocity and the magnetic field vector in these regions using two-component
inversions of the observed Stokes profiles with the help of the SIR code. We
follow these regions during their lifetime to study their temporal behavior.
Finally, we carry out a statistical analysis of the detected supersonic
downflows to characterize their physical properties. Supersonic downflows are
contained in compact patches moving outward, which are located in the mid and
outer penumbra. They are observed as bright, roundish structures at the outer
end of penumbral filaments that resemble penumbral grains. The patches may
undergo fragmentations and mergings during their lifetime, even some of them
are recurrents. Supersonic downflows are associated with strong and rather
vertical magnetic fields with a reversed polarity compared to that of the
sunspot. Our results suggest that downflows returning back to the solar surface
with supersonic velocities are abruptly stopped in dense deep layers and
produce a shock. Consequently, this shock enhances the temperature and is
detected as a bright grain in the continuum filtergrams, which could explain
the existence of outward moving grains in the mid and outer penumbra.


title: An Analysis of the Cloud Computing Security Problem

abstract:
  Cloud computing is a new computational paradigm that offers an innovative
business model for organizations to adopt IT without upfront investment.
Despite the potential gains achieved from the cloud computing, the model
security is still questionable which impacts the cloud model adoption. The
security problem becomes more complicated under the cloud model as new
dimensions have entered into the problem scope related to the model
architecture, multi-tenancy, elasticity, and layers dependency stack. In this
paper we introduce a detailed analysis of the cloud security problem. We
investigated the problem from the cloud architecture perspective, the cloud
offered characteristics perspective, the cloud stakeholders' perspective, and
the cloud service delivery models perspective. Based on this analysis we derive
a detailed specification of the cloud security problem and key features that
should be covered by any proposed security solution.


title: Entropic properties of $D$-dimensional Rydberg systems

abstract:
  The fundamental information-theoretic measures (the R\'enyi $R_{p}[\rho]$ and
Tsallis $T_{p}[\rho]$ entropies, $p>0$) of the highly-excited (Rydberg) quantum
states of the $D$-dimensional ($D>1$) hydrogenic systems, which include the
Shannon entropy ($p \to 1$) and the disequilibrium ($p = 2$), are analytically
determined by use of the strong asymptotics of the Laguerre orthogonal
polynomials which control the wavefunctions of these states. We first realize
that these quantities are derived from the entropic moments of the
quantum-mechanical probability $\rho(\vec{r})$ densities associated to the
Rydberg hydrogenic wavefunctions $\Psi_{n,l,\{\mu\}}(\vec{r})$, which are
closely connected to the $\mathfrak{L}_{p}$-norms of the associated Laguerre
polynomials. Then, we determine the ($n\to\infty$)-asymptotics of these norms
in terms of the basic parameters of our system (the dimensionality $D$, the
nuclear charge and the hyperquantum numbers $(n,l,\{\mu\}$) of the state) by
use of recent techniques of approximation theory. Finally, these three entropic
quantities are analytically and numerically discussed in terms of the basic
parameters of the system for various particular states.


title:
A note on the spectrum of composition operators on spaces of real
  analytic functions

abstract:
  In this paper the spectrum of composition operators on the space of real
analytic functions is investigated. In some cases it is completely determined
while in some other cases it is only estimated.


title: Galaxy clusters as probes for cosmology and dark matter

abstract:
  In recent years, significant progress has been made in building new galaxy
clusters samples, at low and high redshifts, from wide-area surveys,
particularly exploiting the Sunyaev--Zel'dovich (SZ) effect. A large effort is
underway to identify and characterize these new systems with optical/NIR and
X-ray facilities, thus opening new avenues to constraint cosmological models
using structure growth and geometrical tests. A census of galaxy clusters sets
constraints on reionization mechanisms and epochs, which need to be reconciled
with recent limits on the reionization optical depth from cosmic microwave
background (CMB) experiments. Future advances in SZ effect measurements will
include the possibility to (unambiguously) measure directly the kinematic SZ
effect, to build an even larger catalogue of galaxy clusters able to study the
high redshift universe, and to make (spatially-)resolved galaxy cluster maps
with even spectral capability to (spectrally-)resolve the relativistic
corrections of the SZ effect.