title:
Interference alignment for downlink cellular networks: Joint scheduling
  and precoding

abstract:
  Interference Alignment (IA) is technique that, in a large sense, makes use of
the increasing signal dimensions available in the system through MIMO and OFDM
technologies in order to globally reduce the interference suffered by users in
a network. In this paper, we address the problem of downlink cellular networks,
the so-called interfering broadcast channels, where mobile users at cell edges
may suffer from high interference and thus, poor performance. Starting from the
downlink IA scheme proposed by Suh et al., a new approach is proposed where
each user feeds back multiple selected received signal directions with high
signal-to-interference gain. A exhaustive search based scheduler selects a
subset of users to be served simultaneously, balancing between sum-rate
performance and fairness, but becomes untractable in dense network scenarios
where many users send simultaneous requests. Therefore, we develop a
sub-optimal scheduler that greatly decreases the complexity while preserving a
near-optimal data rate gain. More interestingly, our simulations show that the
IA scheme becomes valuable only in correlated channels, whereas the matched
filtering based scheme performs the best in the uncorrelated scenarios.


title: An introduction to Dunkl theory and its analytic aspects

abstract:
  Dunkl theory is a far reaching generalization of Fourier analysis and special
function theory related to root systems. During the sixties and seventies, it
became gradually clear that radial Fourier analysis on rank one symmetric
spaces was closely connected with certain classes of special functions in one
variable. During the eighties, several attempts were made, mainly by the Dutch
school, to extend these results in higher rank (i.e. in several variables),
until the discovery of Dunkl operators in the rational case and Cherednik
operators in the trigonometric case. Together with q-special functions
introduced by Macdonald, this has led to a beautiful theory, developed by
several authors, which encompasses in a unified way harmonic analysis on all
Riemannian symmetric spaces and spherical functions thereon.In this series of
lectures, delivered at the Summer School AAGADE 2015 (Analytic, Algebraic and
Geometric Aspects of Differential Equations, Mathematical Research and
Conference Center, Bedlewo, Poland, September 2015), we aim at giving an
updated overview of Dunkl theory, with an emphasis on its analytic aspects.


title: Suppression of crosstalk in coupled plasmonic waveguides

abstract:
  We demonstrate the suppression of crosstalk between two dielectric
nanowaveguides by placing an auxiliary linear waveguide between loaded
waveguides spaced by one wavelength. The total cross-sectional dimension of the
system containing two transmission lines is less than two microns that is
hundred times smaller than a cross-section of a system made of dielectric
fiber. The propagating modes in these waveguides are the sum and the difference
of symmetric and antisymmetric modes of the coupled system. Crosstalk is
suppressed by matching the wavenumbers of these modes. The analytically
obtained results are confirmed by numerical simulation.


title: Learning Where to Attend Like a Human Driver

abstract:
  Despite the advent of autonomous cars, it's likely - at least in the near
future - that human attention will still maintain a central role as a guarantee
in terms of legal responsibility during the driving task. In this paper we
study the dynamics of the driver's gaze and use it as a proxy to understand
related attentional mechanisms. First, we build our analysis upon two
questions: where and what the driver is looking at? Second, we model the
driver's gaze by training a coarse-to-fine convolutional network on short
sequences extracted from the DR(eye)VE dataset. Experimental comparison against
different baselines reveal that the driver's gaze can indeed be learnt to some
extent, despite i) being highly subjective and ii) having only one driver's
gaze available for each sequence due to the irreproducibility of the scene.
Eventually, we advocate for a new assisted driving paradigm which suggests to
the driver, with no intervention, where she should focus her attention.


title:
LAMOST Spectrograph Response Curves: Stability and Application to flux
  calibration

abstract:
  The task of flux calibration for LAMOST (Large sky Area Multi-Object
Spectroscopic Telescope) spectra is difficult due to many factors. For example,
the lack of standard stars, flat fielding for large field of view, and
variation of reddening between different stars especially at low galactic
latitudes etc. Poor selection, bad spectral quality, or extinction uncertainty
of standard stars not only might induce errors to the calculated spectral
response curve (SRC), but also might lead to failures in producing final 1D
spectra. In this paper, we inspected spectra with Galactic latitude |b|>=60
degree and reliable stellar parameters, determined through the LAMOST Stellar
Parameter Pipeline (LASP), to study the stability of the spectrograph. To
guarantee the selected stars had been observed by each fiber, we selected
37,931 high quality exposures of 29,000 stars from LAMOST DR2, and more than 7
exposures for each fiber. We calculated the SRCs for each fiber for each
exposure, and calculated the statistics of SRCs for spectrographs with both the
fiber variations and time variations. The result shows that the average
response curve of each spectrograph (henceforth ASPSRC) is relatively stable
with statistical errors <= 10%. From the comparison between each ASPSRC and the
SRCs for the same spectrograph obtained by 2D pipeline, we find that the
ASPSRCs are good enough to use for the calibration. The ASPSRCs have been
applied to spectra which were abandoned by LAMOST 2D pipeline due to the lack
of standard stars, increasing the number of LAMOST spectra by 52,181 in DR2.
Comparing those same targets with SDSS, the relative flux differences between
SDSS spectra and that of LAMOST spectra with the ASPSRC method are less than
10%, which underlines that the ASPSRC method is feasible for LAMOST flux
calibration.


title: Refined Inertia of Matrix Patterns

abstract:
  We explore how the combinatorial arrangement of prescribed zeros in a matrix
affects the possible eigenvalues that the matrix can obtain. We demonstrate
that there are inertially arbitrary patterns having a digraph with no 2-cycle,
unlike what happens for nonzero patterns. We develop a class of patterns that
are refined inertially arbitrary but not spectrally arbitrary, making use of
the property of a properly signed nest. We include a characterization of the
inertially arbitrary and refined inertially arbitrary patterns of order three,
as well as the patterns of order four with the least number of nonzero entries.


title:
The 2015 outburst of the accretion-powered pulsar IGR J00291+5934:
  INTEGRAL and Swift observations

abstract:
  IGR J00291+5934 is the fastest-known accretion-powered X-ray pulsar,
discovered during a transient outburst in 2004. In this paper, we report on
Integral and Swift observations during the 2015 outburst, which lasts for
$\sim25$ d. The source has not been observed in outburst since 2008, suggesting
that the long-term accretion rate has decreased by a factor of two since
discovery. The averaged broad-band (0.1 - 250 keV) persistent spectrum in 2015
is well described by a thermal Comptonization model with a column density of
$N_{\rm H} \approx4\times10^{21}$ cm$^{-2}$, a plasma temperature of $kT_{\rm
e} \approx50$ keV, and a Thomson optical depth of $\tau_{\rm T}\approx1$.
Pulsations at the known spin period of the source are detected in the Integral
data up to the $\sim150$ keV energy band. We also report on the discovery of
the first thermonuclear burst observed from IGR J00291+5934, which lasts around
7 min and occurs at a persistent emission level corresponding to roughly
$1.6\%$ of the Eddington accretion rate. The properties of the burst suggest it
is powered primarily by helium ignited at a depth of $y_{\rm
ign}\approx1.5\times10^9$ g cm$^{-2}$ following the exhaustion by steady
burning of the accreted hydrogen. The Swift/BAT data from the first $\sim20$ s
of the burst provide indications of a photospheric radius expansion phase.
Assuming this is the case, we infer a source distance of $d = 4.2 \pm 0.3$ kpc.


title: The Off-Switch Game

abstract:
  It is clear that one of the primary tools we can use to mitigate the
potential risk from a misbehaving AI system is the ability to turn the system
off. As the capabilities of AI systems improve, it is important to ensure that
such systems do not adopt subgoals that prevent a human from switching them
off. This is a challenge because many formulations of rational agents create
strong incentives for self-preservation. This is not caused by a built-in
instinct, but because a rational agent will maximize expected utility and
cannot achieve whatever objective it has been given if it is dead. Our goal is
to study the incentives an agent has to allow itself to be switched off. We
analyze a simple game between a human H and a robot R, where H can press R's
off switch but R can disable the off switch. A traditional agent takes its
reward function for granted: we show that such agents have an incentive to
disable the off switch, except in the special case where H is perfectly
rational. Our key insight is that for R to want to preserve its off switch, it
needs to be uncertain about the utility associated with the outcome, and to
treat H's actions as important observations about that utility. (R also has no
incentive to switch itself off in this setting.) We conclude that giving
machines an appropriate level of uncertainty about their objectives leads to
safer designs, and we argue that this setting is a useful generalization of the
classical AI paradigm of rational agents.


title:
Compressive Data Aggregation on Mobile Wireless Sensor Networks for
  Sensing in Bike Races

abstract:
  -This paper presents an efficient approach to data collection in mobile
wireless sensor networks, with the specific application of sensing in bike
races. Recent sensor technology permits to track GPS position of each bike.
Because of the inherent correlation between bike positions in a bike race, a
simple GPS log is inefficient. The idea presented in this work is to aggregate
GPS data at sensors using compressive sensing techniques. We enforce, in
addition to signal sparsity, a spatial prior on biker motion because of the
group behaviour (peloton) in bike races. The spatial prior is modeled by a
graphical model and the data aggregation problem is solved, with both the
sparsity and the spatial prior, by belief propagation. We validate our approach
on a bike race simulator using trajectories of motorbikes in a real bike race,
the "crit{\'e}rium du dauphin{\'e} 20XX" .


title:
Zero-Point Energy Leakage in Quantum Thermal Bath Molecular Dynamics
  Simulations

abstract:
  The quantum thermal bath (QTB) has been presented as analternative to
path-integral-based methods to introduce nuclear quantumeffects in molecular
dynamics simulations. The method has proved to beefficient, yielding accurate
results for various systems. However, the QTBmethod is prone to zero-point
energy leakage (ZPEL) in highly anharmonicsystems. This is a well-known problem
in methods based on classicaltrajectories where part of the energy of the
high-frequency modes istransferred to the low-frequency modes leading to a
wrong energydistribution. In some cases, the ZPEL can have dramatic
consequences onthe properties of the system. Thus, we investigate the ZPEL by
testing theQTB method on selected systems with increasing complexity in order
to studythe conditions and the parameters that influence the leakage. We also
analyze the consequences of the ZPEL on the structuraland vibrational
properties of the system. We find that the leakage is particularly dependent on
the damping coefficient and thatincreasing its value can reduce and, in some
cases, completely remove the ZPEL. When using sufficiently high values for
thedamping coefficient, the expected energy distribution among the vibrational
modes is ensured. In this case, the QTB methodgives very encouraging results.
In particular, the structural properties are well-reproduced. The dynamical
properties should beregarded with caution although valuable information can
still be extracted from the vibrational spectrum, even for large values ofthe
damping term.


title: On Stochastic Sensor Network Scheduling for Multiple Processes

abstract:
  We consider the problem of multiple sensor scheduling for remote state
estimation of multiple process over a shared link. In this problem, a set of
sensors monitor mutually independent dynamical systems in parallel but only one
sensor can access the shared channel at each time to transmit the data packet
to the estimator. We propose a stochastic event-based sensor scheduling in
which each sensor makes transmission decisions based on both channel
accessibility and distributed event-triggering conditions. The corresponding
minimum mean squared error (MMSE) estimator is explicitly given. Considering
information patterns accessed by sensor schedulers, time-based ones can be
treated as a special case of the proposed one. By ultilizing realtime
information, the proposed schedule outperforms the time-based ones in terms of
the estimation quality. Resorting to solving an Markov decision process (MDP)
problem with average cost criterion, we can find optimal parameters for the
proposed schedule. As for practical use, a greedy algorithm is devised for
parameter design, which has rather low computational complexity. We also
provide a method to quantify the performance gap between the schedule optimized
via MDP and any other schedules.


title: Simulating thimble regularization of lattice quantum field theories

abstract:
  Monte Carlo simulations of lattice quantum field theories on Lefschetz
thimbles are non trivial. We discuss a new Monte Carlo algorithm based on the
idea of computing contributions to the functional integral which come from
complete flow lines. The latter are the steepest ascent paths attached to
critical points, i.e. the basic building blocks of thimbles. The measure to
sample is thus dictated by the contribution of complete flow lines to the
partition function. The algorithm is based on a heat bath sampling of the
gaussian approximation of the thimble: this defines the proposals for a
Metropolis-like accept/reject step. The effectiveness of the algorithm has been
tested on a few models, e.g. the chiral random matrix model. We also discuss
thimble regularization of gauge theories, and in particular the successfull
application to 0+1 dimensional QCD and the status and prospects for Yang-Mills
theories.


title:
Phototaxis beyond turning: persistent accumulation and response
  acclimation of the microalga Chlamydomonas reinhardtii

abstract:
  Phototaxis is an important reaction to light displayed by a wide range of
motile microorganisms. Flagellated eukaryotic microalgae in particular, like
the model organism Chlamydomonas reinhardtii, steer either towards or away from
light by a rapid and precisely timed modulation of their flagellar activity.
Cell steering, however, is only the beginning of a much longer process which
ultimately allows cells to determine their light exposure history. This process
is not well understood. Here we present a first quantitative study of the long
timescale phototactic motility of Chlamydomonas at both single cell and
population levels. Our results reveal that the phototactic strategy adopted by
these microorganisms leads to an efficient exposure to light, and that the
phototactic response is modulated over typical timescales of tens of seconds.
The adaptation dynamics for phototaxis and chlorophyll fluorescence show a
striking quantitative agreement, suggesting that photosynthesis controls
quantitatively how cells navigate a light field.


title:
A note on generalized hydrodynamics: inhomogeneous fields and other
  concepts

abstract:
  Generalized hydrodynamics (GHD) was proposed recently as a formulation of
hydrodynamics for integrable systems, taking into account infinitely-many
conservation laws. In this note we further develop the theory in various
directions. By extending GHD to all commuting flows of the integrable model, we
provide a full description of how to take into account weakly varying force
fields, temperature fields and other inhomogeneous external fields within GHD.
We expect this can be used, for instance, to characterize the non-equilibrium
dynamics of one-dimensional Bose gases in trap potentials. We further show how
the equations of state at the core of GHD follow from the continuity relation
for entropy, and we show how to recover Euler-like equations and discuss
possible viscosity terms.

categories: cond-mat.stat-mech cond-mat.str-el hep-th math-ph math.MP


title: On some combinatorial formulae coming from Hessian Topology

abstract:
  The interaction between combinatorics and algebraic and differential geometry
is very strong. While researching a problem of Hessian topology, we came across
a series of identities of binomial coefficients, which are useful for proving a
topological property of certain spaces whose elements are graphs of a class of
hyperbolic polynomials. These identities are proven by different methods in
combinatorics.


title:
Lipschitz and H\"older stability of optimization problems and
  generalized equations

abstract:
  This paper studies stability aspects of solutions of parametric mathematical
programs and generalized equations, respectively, with disjunctive constraints.
We present sufficient conditions that, under some constraint qualifications
ensuring metric subregularity of the constraint mapping, continuity results of
upper Lipschitz and upper H\"older type, respectively, hold. Furthermore, we
apply the above results to parametric mathematical programs with equilibrium
constraints and demonstrate, how some classical results for the nonlinear
programming problem can be recovered and even improved by our theory.


title:
$\mathrm{GL}(2)$-structures in dimension four, $H$-flatness and
  integrability

abstract:
  We show that torsion-free four-dimensional $\mathrm{GL}(2)$-structures are
flat up to a coframe transformation with a mapping taking values in a certain
subgroup $H\subset\mathrm{SL}(4,\mathbb{R})$ which is isomorphic to a
semidirect product of the three-dimensional continuous Heisenberg group
$H_3(\mathbb{R})$ and the Abelian group $\mathbb{R}$. In addition, we show that
the relevant PDE system is integrable in the sense that it admits a
dispersionless Lax-pair.


title: Fast Orthonormal Sparsifying Transforms Based on Householder Reflectors

abstract:
  Dictionary learning is the task of determining a data-dependent transform
that yields a sparse representation of some observed data. The dictionary
learning problem is non-convex, and usually solved via computationally complex
iterative algorithms. Furthermore, the resulting transforms obtained generally
lack structure that permits their fast application to data. To address this
issue, this paper develops a framework for learning orthonormal dictionaries
which are built from products of a few Householder reflectors. Two algorithms
are proposed to learn the reflector coefficients: one that considers a
sequential update of the reflectors and one with a simultaneous update of all
reflectors that imposes an additional internal orthogonal constraint. The
proposed methods have low computational complexity and are shown to converge to
local minimum points which can be described in terms of the spectral properties
of the matrices involved. The resulting dictionaries balance between the
computational complexity and the quality of the sparse representations by
controlling the number of Householder reflectors in their product. Simulations
of the proposed algorithms are shown in the image processing setting where
well-known fast transforms are available for comparisons. The proposed
algorithms have favorable reconstruction error and the advantage of a fast
implementation relative to the classical, unstructured, dictionaries.


title: Learning Fast Sparsifying Transforms

abstract:
  Given a dataset, the task of learning a transform that allows sparse
representations of the data bears the name of dictionary learning. In many
applications, these learned dictionaries represent the data much better than
the static well-known transforms (Fourier, Hadamard etc.). The main downside of
learned transforms is that they lack structure and therefore they are not
computationally efficient, unlike their classical counterparts. These posse
several difficulties especially when using power limited hardware such as
mobile devices, therefore discouraging the application of sparsity techniques
in such scenarios. In this paper we construct orthogonal and non-orthogonal
dictionaries that are factorized as a product of a few basic transformations.
In the orthogonal case, we solve exactly the dictionary update problem for one
basic transformation, which can be viewed as a generalized Givens rotation, and
then propose to construct orthogonal dictionaries that are a product of these
transformations, guaranteeing their fast manipulation. We also propose a method
to construct fast square but non-orthogonal dictionaries that are factorized as
a product of few transforms that can be viewed as a further generalization of
Givens rotations to the non-orthogonal setting. We show how the proposed
transforms can balance very well data representation performance and
computational complexity. We also compare with classical fast and learned
general and orthogonal transforms.


title: Zonostrophic instability driven by discrete particle noise

abstract:
  The consequences of discrete particle noise for a system possessing a
possibly unstable collective mode are discussed. It is argued that a
zonostrophic instability (of homogeneous turbulence to the formation of zonal
flows) occurs just below the threshold for linear instability. The scenario
provides a new interpretation of the random forcing that is ubiquitously
invoked in stochastic models such as the second-order cumulant expansion (CE2)
or stochastic structural instability theory (SSST); neither intrinsic
turbulence nor coupling to extrinsic turbulence is required. A representative
calculation of the zonostrophic neutral curve is made for a simple two-field
model of toroidal ion-temperature-gradient-driven modes. To the extent that the
damping of zonal flows is controlled by the ion--ion collision rate, the point
of zonostrophic instability is independent of that rate.


title:
On the existence of solutions for stationary mean-field games with
  congestion

abstract:
  Mean-field games (MFGs) are models of large populations of rational agents
who seek to optimize an objective function that takes into account their
location and the distribution of the remaining agents. Here, we consider
stationary MFGs with congestion and prove the existence of stationary
solutions. Because moving in congested areas is difficult, agents prefer to
move in non-congested areas. As a consequence, the model becomes singular near
the zero density. The existence of stationary solutions was previously obtained
for MFGs with quadratic Hamiltonians thanks to a very particular identity.
Here, we develop robust estimates that give the existence of a solution for
general subquadratic Hamiltonians.


title: Primitive groups, road closures, and idempotent generation

abstract:
  We are interested in semigroups of the form $\langle G,a\rangle\setminus G$,
where $G$ is a permutation group of degree $n$ and $a$ a non-permutation on the
domain of $G$. A theorem of the first author, Mitchell and Schneider shows
that, if this semigroup is idempotent-generated for all possible choices of
$a$, then $G$ is the symmetric or alternating group of degree $n$, with three
exceptions (having $n=5$ or $n=6$). Our purpose here is to prove stronger
results where we assume that $\langle G,a\rangle\setminus G$ is
idempotent-generated for all maps of fixed rank $k$. For $k\ge6$ and
$n\ge2k+1$, we reach the same conclusion, that $G$ is symmetric or alternating.
These results are proved using a stronger version of the \emph{$k$-universal
transversal property} previously considered by the authors.
  In the case $k=2$, we show that idempotent generation of the semigroup for
all choices of $a$ is equivalent to a condition on the permutation group $G$,
stronger than primitivity, which we call the \emph{road closure condition}. We
cannot determine all the primitive groups with this property, but we give a
conjecture about their classification, and a body of evidence (both theoretical
and computational) in support of the conjecture.
  The paper ends with some problems.


title: EW corrections to $t \bar t$ distributions: the photon PDF effect

abstract:
  In this proceeding we present the impact of the EW corrections on $t \bar t$
distributions focusing on the effect of the photon PDF. We use the {\sc
NNPDF2.3QED} and {\sc CT14QED} PDF sets, which include the photon PDF. We
discuss a detailed comparison between the results obtained from these two PDF
sets at NLO QCD+EW accuracy for 13 TeV, focusing on the top-quark $p_T$ and the
top-quark pair rapidity. We point out the differences between these two PDF
sets and we show that the rapidity of the top-quark pair can be used in order
to constrain the photon PDF predicted by the {\sc NNPDF2.3QED} set.


title:
On the stability and quality of power grids subjected to intermittent
  feed-in

abstract:
  Feed-in fluctuations induced by renewables are one of the key challenges to
the stability and quality of electrical power grids. In particular short-term
fluctuations disturb the system on a time scale, on which load balancing does
not operate yet and the system is intrinsically governed by self-organized
synchronization. Wind and solar power are known to be strongly non-Gaussian
with intermittent increment statistics in these time scales. We investigate the
impact of short-term wind fluctuations on the basis of a Kuramoto-like power
grid model considering stability in terms of desynchronization and frequency
and voltage quality aspects. We compare intermittent feed-in with a realistic
power spectrum, correlated Gaussian noise of the same spectrum, and Gaussian
white noise. We found out that the likelihood of severe outages is mainly
determined by the temporal correlation of the feed-in. The intermittent nature
of wind power is transferred into frequency and voltage fluctuations. This
establishes a novel type of fluctuations with severe consequences on frequency
and voltage quality, which are beyond engineering status of knowledge.


title:
On computation of limiting coderivatives of the normal-cone mapping to
  inequality systems and their applications

abstract:
  The paper concerns the computation of the limiting coderivative of the
normal-cone mapping related to $C^{2}$ inequality constraints under weak
qualification conditions. The obtained results are applied to verify the Aubin
property of solution maps to a class of parameterized generalized equations.


title: Linearization of a warped $f(R)$ theory in the higher-order frame

abstract:
  The linearization of a type of $f(R)$ gravity is studied directly in the
higher-order frame for an arbitrary five-dimensional warped space-time
background. The quadratic actions of the normal modes of the scalar, vector,
and tensor perturbations are derived by taking the curvature gauge, under which
the linear perturbation of the scalar curvature is zero, and all the
perturbation equations reduce to second order. By comparing our results to
those obtained in the Einstein frame, we find that the quadratic actions of the
normal modes are equivalent for these two frames.


title:
Optically probing the detection mechanism in a molybdenum silicide
  superconducting nanowire single-photon detector

abstract:
  We experimentally investigate the detection mechanism in a meandered
molybdenum silicide (MoSi) superconducting nanowire single-photon detector by
characterising the detection probability as a function of bias current in the
wavelength range of 750 to 2050 nm. Contrary to some previous observations on
niobium nitride (NbN) or tungsten silicide (WSi) detectors, we find that the
energy-current relation is nonlinear in this range. Furthermore, thanks to the
presence of a saturated detection efficiency over the whole range of
wavelengths, we precisely quantify the shape of the curves. This allows a
detailed study of their features, which are indicative of both Fano
fluctuations and position-dependent effects.


title:
Finite-Size Scaling of a First-Order Dynamical Phase Transition:
  Adaptive Population Dynamics and an Effective Model

abstract:
  We analyze large deviations of the time-averaged activity in the one
dimensional Fredrickson-Andersen model, both numerically and analytically. The
model exhibits a dynamical phase transition, which appears as a singularity in
the large deviation function. We analyze the finite-size scaling of this phase
transition numerically, by generalizing an existing cloning algorithm to
include a multi-canonical feedback control: this significantly improves the
computational efficiency. Motivated by these numerical results, we formulate an
effective theory for the model in the vicinity of the phase transition, which
accounts quantitatively for the observed behavior. We discuss potential
applications of the numerical method and the effective theory in a range of
more general contexts.


title:
AdaScan: Adaptive Scan Pooling in Deep Convolutional Neural Networks for
  Human Action Recognition in Videos

abstract:
  We propose a novel method for temporally pooling frames in a video for the
task of human action recognition. The method is motivated by the observation
that there are only a small number of frames which, together, contain
sufficient information to discriminate an action class present in a video, from
the rest. The proposed method learns to pool such discriminative and
informative frames, while discarding a majority of the non-informative frames
in a single temporal scan of the video. Our algorithm does so by continuously
predicting the discriminative importance of each video frame and subsequently
pooling them in a deep learning framework. We show the effectiveness of our
proposed pooling method on standard benchmarks where it consistently improves
on baseline pooling methods, with both RGB and optical flow based Convolutional
networks. Further, in combination with complementary video representations, we
show results that are competitive with respect to the state-of-the-art results
on two challenging and publicly available benchmark datasets.


title: Hall monoidal categories and categorical modules

abstract:
  We construct so called Hall monoidal categories (and Hall modules thereover)
and exhibit them as a categorification of classical Hall and Hecke algebras
(and certain modules thereover). The input of the (functorial!) construction
are simplicial groupoids satisfying the $2$-Segal conditions (as introduced by
Dyckerhoff and Kapranov), the main examples come from Waldhausen's
S-construction. To treat the case of modules, we introduce a relative version
of the $2$-Segal conditions.
  Furthermore, we generalize a classical result about the representation theory
of symmetric groups to the case of wreath product groups: We construct a
monoidal equivalence between the category of complex $G\wr S_n$-representations
(for a fixed finite group $G$ and varying $n\in\mathbb N$) and the category of
"$G$-equivariant" polynomial functors; we use this equivalence to prove a
version of Schur-Weyl duality for wreath products.


title:
Computing with volatile memristors: An application of non-pinched
  hysteresis

abstract:
  The possibility of in-memory computing with volatile memristive devices,
namely, memristors requiring a power source to sustain their memory, is
demonstrated. We have adopted a hysteretic graphene-based field emission
structure as a prototype of volatile memristor, which is characterized by a
non-pinched hysteresis loop. Memristive model of the structure is developed and
used to simulate a polymorphic circuit implementing in-memory computing gates
such as the material implication. Specific regions of parameter space realizing
useful logic functions are identified. Our results are applicable to other
realizations of volatile memory devices.


title:
Effect of the rotation, tidal dissipation history and metallicity of
  stars on the evolution of close-in planets

abstract:
  Since 1995, numerous close-in planets have been discovered around low-mass
stars (M to A-type stars). These systems are susceptible to be tidally
evolving, in particular the dissipation of the kinetic energy of tidal flows in
the host star may modify its rotational evolution and also shape the orbital
architecture of the surrounding planetary system. Recent theoretical studies
have shown that the amplitude of the stellar dissipation can vary over several
orders of magnitude as the star evolves, and that it also depends on the
stellar mass and rotation. We present here one of the first studies of the
dynamics of close-in planets orbiting low-mass stars (from $0.6~M_\odot$ to
$1.2~M_\odot$) where we compute the simultaneous evolution of the star's
structure, rotation and tidal dissipation in its external convective envelope.
We demonstrate that tidal friction due to the stellar dynamical tide, i.e.
tidal inertial waves (their restoring force is the Coriolis acceleration)
excited in the convection zone, can be larger by several orders of magnitude
than the one of the equilibrium tide currently used in celestial mechanics.
This is particularly true during the Pre Main Sequence (PMS) phase and to a
lesser extent during the Sub Giant (SG) phase. Numerical simulations show that
only the high dissipation occurring during the PMS phase has a visible effect
on the semi-major axis of close-in planets. We also investigate the effect of
the metallicity of the star on the tidal evolution of planets. We find that the
higher the metallicity of the star, the higher the dissipation and the larger
the tidally-induced migration of the planet.


title: A Slow Relative of Hofstadter's Q-Sequence

abstract:
  Hofstadter's Q-sequence remains an enigma fifty years after its introduction.
Initially, the terms of the sequence increase monotonically by 0 or 1 at a
time. But, Q(12)=8 while Q(11)=6, and monotonicity fails shortly thereafter. In
this paper, we add a third term to Hofstadter's recurrence, giving the
recurrence B(n)=B(n-B(n-1))+B(n-B(n-2))+B(n-B(n-3)). We show that this
recurrence, along with a suitable initial condition that naturally generalizes
Hofstadter's initial condition, generates a sequence whose terms all increase
monotonically by 0 or 1 at a time. Furthermore, we give a complete description
of the resulting frequency sequence, which allows the nth term of our sequence
to be efficiently computed. We conclude by showing that our sequence cannot be
easily generalized.


title:
Nature of the MHD and kinetic scale turbulence in the magnetosheath of
  Saturn: Cassini observations

abstract:
  Low frequency turbulence in Saturn's magnetosheath is investigated using
in-situ measurements of the Cassini spacecraft. Focus is put on the magnetic
energy spectra computed in the frequency range $\sim[10^{-4}, 1]$Hz. A set of
42 time intervals in the magnetosheath were analyzed and three main results
that contrast with known features of solar wind turbulence are reported: 1) The
magnetic energy spectra showed a $\sim f^{-1}$ scaling at MHD scales followed
by an $\sim f^{-2.6}$ scaling at the sub-ion scales without forming the
so-called inertial range; 2) The magnetic compressibility and the
cross-correlation between the parallel component of the magnetic field and
density fluctuations $ C(\delta n,\delta B_{||}) $ indicates the dominance of
the compressible magnetosonic slow-like modes at MHD scales rather than the
Alfv\'en mode; 3) Higher order statistics revealed a monofractal (resp.
multifractal) behaviour of the turbulent flow downstream of a
quasi-perpendicular (resp. quasi-parallel) shock at the sub-ion scales.
Implications of these results on theoretical modeling of space plasma
turbulence are discussed.


title:
Vacancy in graphene: insight on magnetic properties from theoretical
  modeling

abstract:
  Magnetic properties of a single vacancy in graphene is a relevant and still
much discussed problem. The experimental results point to a clearly detectable
magnetic defect state at the Fermi energy, while calculations based on density
functional theory (DFT) yield widely varying results for the magnetic moment,
in the range of $\mu=1.04-2.0$ $\mu_{B}$. We present a multi-tool \textit{ab
initio} theoretical study of the same defect, using two simulation protocols
for a defect in a crystal (cluster and periodic boundary conditions) and
different DFT functionals - bare and hybrid DFT, mixing a fraction of
Hartree-Fock exchange (XC). Our main conclusions are two-fold: First, we find
that due to the $\pi$-character of the Fermi-energy states of graphene,
inclusion of XC is crucial and for a single isolated vacancy we can predict an
integer magnetic moment $\mu=2\mu_{B}$. Second, we find that due to the
specific symmetry of the graphene lattice, periodic arrays of single vacancies
may provide interesting diffuse spin-spin interactions.


title: On multicolor Ramsey number for 3-paths of length three

abstract:
  We show that if we color the hyperedges of the complete $3$-uniform complete
graph on $2n+\sqrt{18n+1}+2$ vertices with $n$ colors, then one of the color
classes contains a loose path of length three.


title:
Limitations on the recovery of the true AGN variability parameters using
  Damped Random Walk modeling

abstract:
  Context: The damped random walk (DRW) stochastic process is nowadays
frequently used to model aperiodic light curves of AGNs. A number of
correlations between the DRW model parameters, the signal decorrelation
timescale and amplitude, and the physical AGN parameters such as the black hole
mass or luminosity have been reported. Aims: We are interested in whether it is
plausible to correctly measure the DRW parameters from a typical ground-based
survey, in particular how accurate the recovered DRW parameters are compared to
the input ones. Methods: By means of Monte Carlo simulations of AGN light
curves, we study the impact of the light curve length, the source magnitude,
cadence, and additional light on the DRW model parameters. Results: The most
significant finding is that currently existing surveys are going to return
unconstrained DRW decorrelation timescales, because typical rest-frame data do
not probe long enough timescales or the white noise part of PSD for DRW. The
experiment length must be at least ten times longer than the true DRW
timescale, being presumably in the vicinity of one year, meaning a minimum
10-years-long AGN light curves (rest-frame). The DRW timescales for
sufficiently long light curves are typically weakly biased, and the exact bias
depends on the fitting method and used priors. The DRW amplitude is mostly
affected by the photometric noise (so the source magnitude or the
signal-to-noise ratio), cadence, and the AGN host light. Conclusions: Because
the DRW parameters appear to be incorrectly determined from typically existing
data, the reported correlations of the DRW variability and physical AGN
parameters from other works seem unlikely to be correct. In particular, the
anti-correlation of the DRW timescale with redshift is a manifestation of the
survey length being too short. Application of DRW to modeling typical AGN
optical light curves is questioned.


title: Representations of unipotent reduction for SO(2n+1), I: an involution

abstract:
  We consider a group SO(2n+1) over a p-adic field, and tempered irreducible
representations of this group, of unipotent reduction. We use the construction
due to Lusztig of these representations. In an old paper with Moeglin, we have
defined an involution in the complex vector space generated by those
representations which are elliptic. It is strongly related to another
involution defined by Lusztig for finite groups. We give a new definition of
our involution and we prove it commutes, in some sense, with Jacquet functor.


title: Search for new physics in semileptonic B-decays

abstract:
  Semileptonic decays provide an excellent environment for testing the Standard
Model (SM). Violation of lepton universality would be a smoking gun for physics
beyond the SM. Using semi-tauonic $B$ decays, LHCb finds a value of
$\mathcal{R}(D^*) = \mathcal{B}(\bar{B}^0 \to D^{*+} \tau^{-}
\bar{\nu}_{\tau})/\mathcal{B}(\bar{B}^0 \to D^{*+} \mu^{-} \bar{\nu}_{\mu}) =
0.336 \pm 0.027 \rm{(stat)} \pm 0.030 \rm{(syst)}$, which is 2.1 standard
deviations larger than the value expected from the SM. Moreover, the
measurement of the $CP$ asymmetry in mixing of $B_s^0$ mesons is highly
sensitive to physics beyond the SM. This article presents the latest result on
semileptonic asymmetries; using the full Run 1 dataset, it is found that
$a_{\rm{sl}}^s = (0.39 \pm 0.26 \rm{(stat)} \pm 0.20 \rm{(syst)})\%$, which is
consistent with the Standard Model.


title:
Approximate axially symmetric solution of the Weyl-Dirac theory of
  gravitation and the spiral galactic rotation problem

abstract:
  On the basis of the Poincare-Weyl gauge theory of gravitation, a new
conformal Weyl-Dirac theory of gravitation is proposed, which is a
gravitational theory in Cartan-Weyl spacetime with the Dirac scalar field
representing the dark matter model. A static approximate axially symmetric
solution of the field equations in vacuum is obtained. On the base of this
solution in the Newtonian approximation one considers the problem of rotation
velocities in spiral components of galaxies.


title:
An Integrated approach for the Secure Transmission of Images based on
  DNA Sequences

abstract:
  As long as human beings exist on this earth, there will be confidential
images intended for limited audience. These images have to be transmitted in
such a way that no unauthorized person gets knowledge of them. DNA sequences
play a vital role in modern cryptography and DNA sequence based cryptography
renders a helping hand for transmission of such confidential images over a
public insecure channel as the intended recipient alone can decipher them. This
paper outlines an integrated encryption scheme based on DNA sequences and
scrambling according to magic square of doubly even order pattern. Since there
is negligible correlation between the original and encrypted image this method
is robust against any type of crypt attack.


title:
A geometric proof of L\"uck's vanishing theorem for the first
  $L^2$-Betti number of the total space of a fibration

abstract:
  A significant theorem of L\"uck says that the first $L^2$-Betti number of the
total space of a fibration vanishes under some conditions on the fundamental
groups. The proof is based on constructions on chain complexes. In the present
paper, we translate the proof into the world of CW-complexes to make it more
accessible.


title: Evolution of networks with multiple junctions

abstract:
  We consider the motion by curvature of a network of curves in the plane and
we discuss existence, uniqueness, singularity formation and asymptotic behavior
of the flow.


title: Inhomogeneous imperfect fluid inflation

abstract:
  A generalized equation of state corresponding to a model that includes a
Chaplygin gas and a viscous term is investigated, in the context of the
reconstruction program in scalar field cosmology. The corresponding
inflationary model parameters can be conveniently adjusted in order to
reproduce the most recent PLANCK data. The influence of the Chaplygin gas term
contribution, in relation with previous models, is discussed. Exit from
inflation is shown to occur quite naturally in the new model.


title:
The Inverse Bagging Algorithm: Anomaly Detection by Inverse Bootstrap
  Aggregating

abstract:
  For data sets populated by a very well modeled process and by another process
of unknown probability density function (PDF), a desired feature when
manipulating the fraction of the unknown process (either for enhancing it or
suppressing it) consists in avoiding to modify the kinematic distributions of
the well modeled one. A bootstrap technique is used to identify sub-samples
rich in the well modeled process, and classify each event according to the
frequency of it being part of such sub-samples. Comparisons with general MVA
algorithms will be shown, as well as a study of the asymptotic properties of
the method, making use of a public domain data set that models a typical search
for new physics as performed at hadronic colliders such as the Large Hadron
Collider (LHC).


title:
Optimality conditions for disjunctive programs based on generalized
  differentiation with application to mathematical programs with equilibrium
  constraints

abstract:
  We consider optimization problems with a disjunctive structure of the
constraints. Prominent examples of such problems are mathematical programs with
equilibrium constraints or vanishing constraints. Based on the concepts of
directional subregularity and their characterization by means of objects from
generalized differentiation, we obtain the new stationarity concept of extended
M-stationarity, which turns out to be an equivalent dual characterization of
B-stationarity. These results are valid under a very weak constraint
qualification of Guignard type which is usually very difficult to verify. We
also state a new constraint qualification which is a little bit stronger but
verifiable. Further we present second-order optimality conditions, both
necessary and sufficient. Finally we apply these results to the special case of
mathematical programs with equilibrium constraints and compute explicitly all
the objects from generalized differentiation. For this type of problems we also
introduce the concept of strong M-stationarity which builds a bridge between
S-stationarity and M-stationarity.


title: Weakly Supervised Cascaded Convolutional Networks

abstract:
  Object detection is a challenging task in visual understanding domain, and
even more so if the supervision is to be weak. Recently, few efforts to handle
the task without expensive human annotations is established by promising deep
neural network. A new architecture of cascaded networks is proposed to learn a
convolutional neural network (CNN) under such conditions. We introduce two such
architectures, with either two cascade stages or three which are trained in an
end-to-end pipeline. The first stage of both architectures extracts best
candidate of class specific region proposals by training a fully convolutional
network. In the case of the three stage architecture, the middle stage provides
object segmentation, using the output of the activation maps of first stage.
The final stage of both architectures is a part of a convolutional neural
network that performs multiple instance learning on proposals extracted in the
previous stage(s). Our experiments on the PASCAL VOC 2007, 2010, 2012 and large
scale object datasets, ILSVRC 2013, 2014 datasets show improvements in the
areas of weakly-supervised object detection, classification and localization.


title:
Solution X-ray scattering (S/WAXS) and structure formation in protein
  dynamics

abstract:
  We propose to develop mean field theory in combination with Glauber
algorithm, to model and interpret protein dynamics and structure formation in
small to wide angle x-ray scattering (S/WAXS) experiments. We develop the
methodology by analysing the Engrailed homeodomain protein as an example. We
demonstrate how to interpret S/WAXS data with a good precision and over an
extended temperature range. We explain experimentally observed phenomena in
terms of protein phase structure, and we make predictions for future
experiments how the scattering data behaves at different ambient temperature
values. We conclude that a combination of mean field theory with Glauber
algorithm has the potential to develop into a highly accurate, computationally
effective and predictive tool for analysing S/WAXS data. Finally, we compare
our results with those obtained previously in an all-atom molecular dynamics
simulation.


title: On Lipschitzian properties of implicit multifunctions

abstract:
  The paper is devoted to the development of new sufficient conditions for the
calmness and the Aubin property of implicit multifunctions. As the basic tool
one employs the directional limiting coderivative which, together with the
graphical derivative, enable us a fine analysis of the local behavior of the
investigated multifunction along relevant directions. For verification of the
calmness property, in addition, a new condition has been discovered which
parallels the missing implicit function paradigm and permits us to replace the
original multifunction by a substantially simpler one. Moreover, as an
auxiliary tool, a handy formula for the computation of the directional limiting
coderivative of the normal-cone map with a polyhedral set has been derived
which perfectly matches the framework of [11]. All important statements are
illustrated by examples.


title:
Automated, Efficient, and Practical Extreme Value Analysis with
  Environmental Applications

abstract:
  Although the fundamental probabilistic theory of extremes has been well
developed, there are many practical considerations that must be addressed in
application. The contribution of this thesis is four-fold. The first concerns
the choice of r in the r largest order statistics modeling of extremes. The
second contribution pertains to threshold selection in the peaks-over-threshold
approach. The third combines a theoretical and methodological approach to
improve estimation within non-stationary regional frequency models of extremal
data
  The methodology developed is demonstrated with climate based applications.
Last, an overview of computational issues for extremes is provided, along with
a brief tutorial of the R package eva, which improves the functionality of
existing extreme value software, as well as providing new implementations.


title:
Correlations Between Human Mobility and Social Interaction Reveal
  General Activity Patterns

abstract:
  A day in the life of a person involves a broad range of activities which are
common across many people. Going beyond diurnal cycles, a central question is:
to what extent do individuals act according to patterns shared across an entire
population? Here we investigate the interplay between different activity types,
namely communication, motion, and physical proximity by analyzing data
collected from smartphones distributed among 638 individuals. We explore two
central questions: Which underlying principles govern the formation of the
activity patterns? Are the patterns specific to each individual or shared
across the entire population? We find that statistics of the entire population
allows us to successfully predict 71\% of the activity and 85\% of the
inactivity involved in communication, mobility, and physical proximity.
Surprisingly, individual level statistics only result in marginally better
predictions, indicating that a majority of activity patterns are shared across
{our sample population}. Finally, we predict short-term activity patterns using
a generalized linear model, which suggests that a simple linear description
might be sufficient to explain a wide range of actions, whether they be of
social or of physical character.


title: The Dixmier property and tracial states for C*-algebras

abstract:
  It is shown that a unital C*-algebra A has the Dixmier property if and only
if it is weakly central and satisfies certain tracial conditions. This
generalises the Haagerup-Zsido theorem for simple C*-algebras. We also study a
uniform version of the Dixmier property, as satisfied for example by von
Neumann algebras and the reduced C*-algebras of Powers groups, but not by all
C*-algebras with the Dixmier property, and we obtain necessary and sufficient
conditions for a simple unital C*-algebra with unique tracial state to have
this uniform property. We give further examples of C*-algebras with the uniform
Dixmier property, namely all C*-algebras with the Dixmier property and finite
radius of comparison-by-traces. Finally, we determine the distance between two
Dixmier sets, in an arbitrary unital C*-algebra, by a formula involving tracial
data and algebraic numerical ranges.


title: Invariable generation of Thompson groups

abstract:
  A subset $S$ of a group $G$ invariably generates $G$ if $G= \langle s^{g(s)}
| s \in S\rangle$ for every choice of $g(s) \in G,s \in S$. We say that a group
$G$ is invariably generated if such $S$ exists, or equivalently if $S=G$
invariably generates $G$. In this paper, we study invariable generation of
Thompson groups. We show that Thompson group $F$ is invariable generated by a
finite set, whereas Thompson groups $T$ and $V$ are not invariable generated.


title: The Holometer: An Instrument to Probe Planckian Quantum Geometry

abstract:
  This paper describes the Fermilab Holometer, an instrument for measuring
correlations of position variations over a four-dimensional volume of
space-time. The apparatus consists of two co-located, but independent and
isolated, 40m power-recycled Michelson interferometers, whose outputs are
cross-correlated to 25 MHz. The data are sensitive to correlations of
differential position across the apparatus over a broad band of frequencies up
to and exceeding the inverse light crossing time, 7.6 MHz. A noise model
constrained by diagnostic and environmental data distinguishes among physical
origins of measured correlations, and is used to verify shot-noise-limited
performance. These features allow searches for exotic quantum correlations that
depart from classical trajectories at spacelike separations, with a strain
noise power spectral density sensitivity smaller than the Planck time. The
Holometer in current and future configurations is projected to provide
precision tests of a wide class of models of quantum geometry at the Planck
scale, beyond those already constrained by currently operating gravitational
wave observatories.


title:
Researches on Dynamic Load Balancing Algorithms and hp-Adaptivity in 3-D
  Parallel Adaptive Finite Element Computations

abstract:
  This work is related to PHG (Parallel Hierarchical Grid). PHG is a toolbox
for developing parallel adaptive finite element programs, which is under active
development at the State Key Laboratory of Scientific and Engineering
Computing. The main results of this work are as follows.
  1) For the tetrahedral meshes used in PHG, under reasonable assumptions, we
proved the existence of through-vertex Hamiltonian paths between arbitrary two
vertices, as well as the existence of through-vertex Hamiltonian cycles, and
designed an efficient algorithm with linear complexity for constructing
through-vertex Hamiltonian paths. The resulting algorithm has been implemented
in PHG, and is used for ordering elements in the coarsest mesh for the
refinement tree mesh partitioning algorithm.
  2) We designed encoding and decoding algorithms for high dimensional Hilbert
order. Hilbert order has good locality, and it has wide applications in various
fields in computer science, such as memory management, database, and dynamic
load balancing.
  3) We implemented refinement tree and space filling curve based mesh
partitioning algorithms in PHG, and designed the dynamic load balancing module
of PHG. The refinement tree based partitioning algorithm was originally
proposed by Mitchell, the one implemented in PHG was improved in several
aspects. The space filling curve based mesh partitioning function in PHG can
use either Hilbert or Morton space filling curve.
  4) We studied existing hp-adaptive strategies in the literature, and proposed
a new strategy. Numerical experiments show that our new strategy achieves
exponential convergence, and is superior, in both precision of the solutions
and computation time, to the strategy compared. This part of the work also
serves to validate the hp-adaptivity module of PHG.


title:
Finite-Length Analysis of Spatially-Coupled Regular LDPC Ensembles on
  Burst-Erasure Channels

abstract:
  Regular spatially-Coupled LDPC (SC-LDPC) ensembles have gained significant
interest since they were shown to universally achieve the capacity of binary
memoryless channels under low-complexity belief-propagation decoding. In this
work, we focus primarily on the performance of these ensembles over binary
channels affected by bursts of erasures. We first develop an analysis of the
finite length performance for a single burst per codeword and no errors
otherwise. We first assume that the burst erases a complete spatial position,
modeling for instance node failures in distributed storage. We provide new
tight lower bounds for the block erasure probability ($P_{\mathrm{B}}$) at
finite block length and bounds on the coupling parameter for being
asymptotically able to recover the burst. We further show that expurgating the
ensemble can improve the block erasure probability by several orders of
magnitude. Later we extend our methodology to more general channel models. In a
first extension, we consider bursts that can start at a random position in the
codeword and span across multiple spatial positions. Besides the finite length
analysis, we determine by means of density evolution the maximnum correctable
burst length. In a second extension, we consider the case where in addition to
a single burst, random bit erasures may occur. Finally, we consider a block
erasure channel model which erases each spatial position independently with
some probability $p$, potentially introducing multiple bursts simultaneously.
All results are verified using Monte-Carlo simulations.


title:
Feedback Control of the Pusher-Slider System: A Story of Hybrid and
  Underactuated Contact Dynamics

abstract:
  This paper investigates real-time control strategies for dynamical systems
that involve frictional contact interactions. Hybridness and underactuation are
key characteristics of these systems that complicate the design of feedback
controllers. In this research, we examine and test a novel feedback controller
design on a planar pushing system, where the purpose is to control the motion
of a sliding object on a flat surface using a point robotic pusher. The
pusher-slider is a simple dynamical system that retains many of the challenges
that are typical of robotic manipulation tasks.
  Our results show that a model predictive control approach used in tandem with
integer programming offers a powerful solution to capture the dynamic
constraints associated with the friction cone as well as the hybrid nature of
the contact. In order to achieve real-time control, simplifications are
proposed to speed up the integer program. The concept of Family of Modes (FOM)
is introduced to solve an online convex optimization problem by selecting a set
of contact mode schedules that spans a large set of dynamic behaviors that can
occur during the prediction horizon. The controller design is applied to
stabilize the motion of a sliding object about a nominal trajectory, and to
re-plan its trajectory in real-time to follow a moving target. We validate the
controller design through numerical simulations and experimental results on an
industrial ABB IRB 120 robotic arm.


title: On measuring performances of C-SPARQL and CQELS

abstract:
  To cope with the massive growth of semantic data streams, several RDF Stream
Processing (RSP) engines have been implemented. The efficiency of their
throughput, latency and memory consumption can be evaluated using available
benchmarks such as LSBench and City- Bench. Nevertheless, these benchmarks lack
an in-depth performance evaluation as some measurement metrics have not been
considered. The main goal of this paper is to analyze the performance of two
popular RSP engines, namely C-SPARQL and CQELS, when varying a set of
performance metrics. More precisely, we evaluate the impact of stream rate,
number of streams and window size on execution time as well as on memory
consumption.


title:
Status connectivity indices and co-indices of graphs and its computation
  to intersection graph, hypercube, Kneser graph and achiral polyhex nanotorus

abstract:
  The status of a vertex $u$ in a connected graph $G$, denoted by
$\sigma_G(u)$, is defined as the sum of the distances between $u$ and all other
vertices of a graph $G$. The first and second status connectivity indices of a
graph $G$ are defined as $S_{1}(G) = \sum_{uv \in E(G)}[\sigma_G(u)+
\sigma_G(v)]$ and $S_{2}(G) = \sum_{uv \in E(G)}\sigma_G(u)\sigma_G(v)$
respectively, where $E(G)$ denotes the edge set of $G$. In this paper we have
defined the first and second status co-indices of a graph $G$ as
$\overline{S_{1}}(G) = \sum_{uv \notin E(G)}[\sigma_G(u)+ \sigma_G(v)]$ and
$\overline{S_{2}}(G) = \sum_{uv \notin E(G)}\sigma_G(u)\sigma_G(v)$
respectively. Relations between status connectivity indices and status
coindices are established. Also these indices are computed for intersection
graph, hypercube, Kneser graph and achiral polyhex nanotorus.


title: Laplacian integrality in P4-sparse and P4-extendible graphs

abstract:
  Let G be a simple graph and L = L(G) the Laplacian matrix of G. G is called
L-integral if all its Laplacian eigenvalues are integer numbers. It is known
that every cograph, a graph free of P4, is L-integral. The class of P4-sparse
graphs and the class of P4-extendible graphs contain the cographs. It seems
natural to investigate if the graphs in these classes are still L-integral. In
this paper we characterized the L-integral graphs for both cases, P4-sparse
graphs and P4-extendible graphs.


title: InstanceCut: from Edges to Instances with MultiCut

abstract:
  This work addresses the task of instance-aware semantic segmentation. Our key
motivation is to design a simple method with a new modelling-paradigm, which
therefore has a different trade-off between advantages and disadvantages
compared to known approaches. Our approach, we term InstanceCut, represents the
problem by two output modalities: (i) an instance-agnostic semantic
segmentation and (ii) all instance-boundaries. The former is computed from a
standard convolutional neural network for semantic segmentation, and the latter
is derived from a new instance-aware edge detection model. To reason globally
about the optimal partitioning of an image into instances, we combine these two
modalities into a novel MultiCut formulation. We evaluate our approach on the
challenging CityScapes dataset. Despite the conceptual simplicity of our
approach, we achieve the best result among all published methods, and perform
particularly well for rare object classes.


title: State Sensitivity Evaluation Within UD Based Array Covariance Filters

abstract:
  This technical note addresses the UD factorization based Kalman filtering
(KF) algorithms. Using this important class of numerically stable KF schemes,
we extend its functionality and develop an elegant and simple method for
computation of sensitivities of the system state to unknown parameters required
in a variety of applications. For instance, it can be used for efficient
calculations in sensitivity analysis and in gradient-search optimization
algorithms for the maximum likelihood estimation. The new theory presented in
this technical note is a solution to the problem formulated by Bierman in ,
which has been open since 1990s. As in the cited paper, our method avoids the
standard approach based on the conventional KF (and its derivatives with
respect to unknown system parameters) with its inherent numerical instabilities
and, hence, improves the robustness of computations against roundoff errors.


title: How transfer flights shape structure of the airline network

abstract:
  In this paper we analyze the gravity model in the world passenger
air-transport network. We show that in the standard form the model is
inadequate to correctly describe the relationship between passenger flows and
typical geo-economic variables that characterize connected countries. We
propose a model of transfer flights which allows to exploit these discrepancies
to discover hidden subflows in the network. We illustrate its usefulness by
retrieving the distance coefficient in the gravity model which is one of the
determinants of the globalization process. Finally, we discuss the correctness
of the presented approach by comparing the distance coefficient to several well
known economical events.


title: Neoclassical flows in deuterium-helium plasma density pedestals

abstract:
  In tokamak transport barriers, the radial scale of profile variations can be
comparable to a typical ion orbit width, which makes the coupling of the
distribution function across flux surfaces important in the collisional
dynamics. We use the radially global steady-state neoclassical {\delta}f code
Perfect to calculate poloidal and toroidal flows, and radial fluxes, in the
pedestal. In particular, we have studied the changes in these quantities as the
plasma composition is changed from a deuterium bulk species with a helium
impurity to a helium bulk with a deuterium impurity, under specific profile
similarity assumptions. The poloidally resolved radial fluxes are not
divergence-free in isolation in the presence of sharp radial profile
variations, which leads to the appearance of poloidal return-flows. These flows
exhibit a complex radial-poloidal structure that extends several orbit widths
into the core and is sensitive to abrupt radial changes in the ion temperature
gradient. We find that a sizable neoclassical toroidal angular momentum
transport can arise in the radially global theory, in contrast to the local.


title: Towards NNLO accuracy for $\varepsilon'/\varepsilon$

abstract:
  The quantity $\varepsilon'/\varepsilon$ measures direct CP violation in Kaon
decays. Recent SM predictions show a $2.9\sigma$ tension with data, with the
theoretical uncertainty dominating. As rapid progress on the lattice is
bringing nonperturbative long-distance effects under control, a more precise
knowledge of short-distance contributions is needed. We describe the first NNLO
results for $\varepsilon'/\varepsilon$ and discuss future prospects, as well as
issues of scheme dependence and the separation of perturbative and
nonperturbative effects. Finally we also comment on the solution of the
renormalisation-group evolution in one of the talks at this conference and
present the correct solution.


title: Lipschitz metric for the Novikov equation

abstract:
  We consider the Lipschitz continuous dependence of solutions for the Novikov
equation with respect to the initial data. In particular, we construct a
Finsler type optimal transport metric which renders the solution map Lipschitz
continuous on bounded set of $H^1(R)\cap W^{1,4}(R)$, although it is not
Lipschitz continuous under the natural Sobolev metric from energy law due to
the finite time gradient blowup. By an application of Thom's transversality
Theorem, we also prove that when the initial data are in an open dense set of
$H^1(R)\cap W^{1,4}(R)$, the solution is piecewise smooth. This generic
regularity result helps us extend the Lipschitz continuous metric to the
general weak solutions.


title:
Recent progress on CP violation in $K\to \pi \pi$ decays in the SM and a
  supersymmetric solution

abstract:
  Using the recent first lattice results of the RBC-UKQCD collaboration for $K
\to \pi\pi$ decays, we perform a phenomenological analysis of
$\epsilon_K^{\prime}/\epsilon_K$ and find a discrepancy between SM prediction
and experiments by $\sim 3\,\sigma$. We discuss an explanation by new physics.
The well-understood value of $\epsilon_K$, which quantifies indirect $CP$
violation, however, typically prevents large new physics contributions to
$\epsilon_K^{\prime}/\epsilon_K$. In this talk, we show a solution of the
$\epsilon_K^{\prime}/\epsilon_K$ discrepancy in the Minimal Supersymmetric
Standard Model with squark masses above 3 TeV without fine-tuning of $CP$
phases. In this solution, the Trojan penguin diagram gives large
isospin-breaking contributions which enhance $\epsilon_K^{\prime}$, while the
contribution to $\epsilon_K$ is suppressed thanks to the Majorana nature of
gluinos.


title: Goldstone models of modified gravity

abstract:
  We investigate scalar-tensor theories where matter couples to the scalar
field via a kinetically dependent conformal coupling. These models can be seen
as the low-energy description of invariant field theories under a global
Abelian symmetry. The scalar field is then identified with the Goldstone mode
of the broken symmetry. It turns out that the properties of these models are
very similar to the ones of ultralocal theories where the scalar-field value is
directly determined by the local matter density. This leads to a complete
screening of the fifth force in the Solar System and between compact objects,
through the ultralocal screening mechanism. On the other hand, the fifth force
can have large effects in extended structures with large-scale density
gradients, such as galactic halos. Interestingly, it can either amplify or damp
Newtonian gravity, depending on the model parameters. We also study the
background cosmology and the linear cosmological perturbations. The background
cosmology is hardly different from its $\Lambda$-CDM counterpart whilst
cosmological perturbations crucially depend on whether the coupling function is
convex or concave. For concave functions, growth is hindered by the
repulsiveness of the fifth force whilst it is enhanced in the convex case. In
both cases, the departures from the $\Lambda$-CDM cosmology increase on smaller
scales and peak for galactic structures. For concave functions, the formation
of structure is largely altered below some characteristic mass, as smaller
structures are delayed and would form later through fragmentation, as in some
warm dark matter scenarios. For convex models, small structures form more
easily than in the $\Lambda$-CDM scenario.


title:
Two-Level Structural Sparsity Regularization for Identifying Lattices
  and Defects in Noisy Images

abstract:
  This paper presents a regularized regression model with a two-level
structural sparsity penalty applied to locate individual atoms in a noisy
scanning transmission electron microscopy image (STEM). In crystals, the
locations of atoms is symmetric, condensed into a few lattice groups.
Therefore, by identifying the underlying lattice in a given image, individual
atoms can be accurately located. We propose to formulate the identification of
the lattice groups as a sparse group selection problem. Furthermore, real
atomic scale images contain defects and vacancies, so atomic identification
based solely on a lattice group may result in false positives and false
negatives. To minimize error, model includes an individual sparsity
regularization in addition to the group sparsity for a within-group selection,
which results in a regression model with a two-level sparsity regularization.
We propose a modification of the group orthogonal matching pursuit (gOMP)
algorithm with a thresholding step to solve the atom finding problem. The
convergence and statistical analyses of the proposed algorithm are presented.
The proposed algorithm is also evaluated through numerical experiments with
simulated images. The applicability of the algorithm on determination of atom
structures and identification of imaging distortions and atomic defects was
demonstrated using three real STEM images. We believe this is an important step
toward automatic phase identification and assignment with the advent of genomic
databases for materials.


title:
Resonant interaction of $\phi^4$ kink with spatially periodic
  $\mathcal{PT}$-symmetric perturbation

abstract:
  The resonant interaction of the $\phi^4$ kink with a periodic
$\mathcal{PT}$-symmetric perturbation is observed in the frame of the continuum
model and with the help of a two degree of freedom collective variable model
derived in PRA 89, 010102(R). When the kink interacts with the perturbation,
the kink's internal mode is excited with the amplitude varying in time
quasiperiodically. The maximal value of the amplitude was found to grow when
the kink velocity is such that it travels one period of perturbation is nearly
one period of the kink's internal mode. It is also found that the kink's
translational and vibrational modes are coupled in a way that an increase in
the kink's internal mode amplitude results in a decrease in kink velocity. The
results obtained with the collective variable method are in a good qualitative
agreement with the numerical simulations for the continuum model. The results
of the present study suggest that kink dynamics in open systems with balanced
gain and loss can have new features in comparison with the case of conservative
systems.


title: Mu-tau reflection symmetry with a texture-zero

abstract:
  The $\mu\tau$-reflection symmetry is a simple symmetry capable of predicting
all the unknown CP phases of the lepton sector and the atmospheric angle but
too simple to predict the absolute neutrino mass scale or the mass ordering. We
show that by combining it with a discrete abelian symmetry in a nontrivial way
we can additionally enforce a texture-zero and obtain a highly predictive
scenario where the lightest neutrino mass is fixed to be in the few meV range
for two normal ordering (NO) solutions or in the tens of meV in one inverted
ordering (IO) solution. The rate for neutrinoless double beta decay is
predicted to be negligible for NO or have effective mass $m_{\beta\beta}\approx
14\text{ -- }29\,{\rm meV}$ for IO, right in the region to be probed in future
experiments.


title:
Finite and Infinite energy solutions of singular elliptic problems:
  Existence and Uniqueness

abstract:
  We establish existence and uniqueness of solution for the homogeneous
Dirichlet problem associated to a fairly general class of elliptic equations
modeled by $$
  -\Delta u= h(u){f} \ \ \text{in}\,\ \Omega, $$ where $f$ is an irregular
datum, possibly a measure, and $h$ is a continuous function that may blow up at
zero. We also provide regularity results on both the solution and the lower
order term depending on the regularity of the data, and we discuss their
optimality.


title: Multilinear Marcinkiewicz-Zygmund inequalities

abstract:
  We extend to the multilinear setting classical inequalities of Marcinkiewicz
and Zygmund on $\ell^r$-valued extensions of linear operators. We show that for
certain $1 \leq p, q_1, \dots, q_m, r \leq \infty$, there is a constant $C\geq
0$ such that for every bounded multilinear operator $T\colon L^{q_1}(\mu_1)
\times \cdots \times L^{q_m}(\mu_m) \to L^p(\nu)$ and functions
$\{f_{k_1}^1\}_{k_1=1}^{n_1} \subset L^{q_1}(\mu_1), \dots,
\{f_{k_m}^m\}_{k_m=1}^{n_m} \subset L^{q_m}(\mu_m)$, the following inequality
holds \begin{equation}\label{MZ ineq abstract} (1) \quad \quad \left\Vert
\left(\sum_{k_1, \dots, k_m} |T(f_{k_1}^1, \dots, f_{k_m}^m)|^r\right)^{1/r}
\right\Vert_{L^p(\nu)} \leq C \|T\| \prod_{i=1}^m \left\|
\left(\sum_{k_i=1}^{n_i} |f_{k_i}^i|^r\right)^{1/r} \right\|_{L^{q_i}(\mu_i)}.
\end{equation} In some cases we also calculate the best constant $C\geq 0$
satisfying the previous inequality. We apply these results to obtain weighted
vector-valued inequalities for multilinear Calder\'on-Zygmund operators.


title:
Higher order quark number fluctuations via imaginary chemical potentials
  in $N_f=2+1$ QCD

abstract:
  We discuss analytic continuation as a tool to extract the cumulants of the
quark number fluctuations in the strongly interacting medium from lattice QCD
simulations at imaginary chemical potentials. The method is applied to $N_f =
2+1$ QCD, discretized with stout improved staggered fermions, physical quark
masses and the tree level Symanzik gauge action, exploring temperatures ranging
from 135 up to 350 MeV and adopting mostly lattices with $N_t = 8$ sites in the
temporal direction. The method is based on a global fit of various cumulants as
a function of the imaginary chemical potentials. We show that it is
particularly convenient to consider cumulants up to order two, and that below
$T_c$ the method can be advantageous, with respect to a direct Montecarlo
sampling at $\mu = 0$, for the determination of generalized susceptibilities of
order four or higher, and especially for mixed susceptibilities, for which the
gain is well above one order of magnitude. We provide cumulants up to order
eight, which are then used to discuss the radius of convergence of the Taylor
expansion and the possible location of the second order critical point at real
$\mu$: no evidence for such a point is found in the explored range of $T$ and
for chemical potentials within present determinations of the pseudo-critical
line.


title:
Unitarity of the time-evolution and observability of non-Hermitian
  Hamiltonians for time-dependent Dyson maps

abstract:
  Here we present an strategy for the derivation of a time-dependent Dyson map
which ensures simultaneously the unitarity of the time evolution and the
observability of a quasi-Hermitian Hamiltonian. The time-dependent Dyson map is
derived through a constructed Schr\"{o}dinger-like equation governed by the
non-Hermitian Hamiltonian itself; despite its time-dependence our scheme
ensures the time-independence of the metric operator, a necessary condition for
the observability of the quasi-Hermitian Hamiltonian. As an illustrative
example we consider a driven Harmonic oscillator described by a time-dependent
non-Hermitian Hamiltonian. After computing the Dyson map and demonstrating the
time-independence of the associated metric operator, we successfully derive an
eigenvalue equation for this time-dependent Hamiltonian which enable us to
analyze the $\mathcal{PT}$-symmetry breaking process.


title: A Mathematical Model of Mechanotransduction

abstract:
  This article reviews the mechanical bidomain model, a mathematical
description how the extracellular matrix and intracellular cytoskeleton are
coupled by integrin proteins. The fundamental hypothesis is that differences
between intracellular and extracellular displacements drive
mechanotransduction. A one-dimensional example illustrates the model, which is
then extended to two dimensions. In several cases the equations are solved
analytically, illustrating how displacements divide into two parts: monodomain
displacements are identical in both spaces and therefore do not contribute to
mechanotransduction, whereas bidomain displacements cause mechanotransduction.
A new length constant depends on the intracellular and extracellular shear
moduli and the integrin spring constant, and bidomain effects often occur
within a few length constants of the tissue edge. Numerical methods for solving
the model equations are being developed. Precursors to the model and potential
applications are discussed. The bidomain model may be applicable to cardiac
remodeling, blood vessel regulation, tissue engineering, stem cell
differentiation, cancer biology, and development.


title: Multi-flavor string-net models

abstract:
  We generalize the string-net construction to multiple flavors of strings,
each of which is labeled by the elements of an abelian group $G_i$. The same
flavor of strings can branch while different flavors of strings can cross one
another and thus they form intersecting string-nets. We systematically
construct the exactly soluble lattice Hamiltonians and the ground state wave
functions for the intersecting string-net condensed phases. We analyze the
braiding statistics of the low energy quasiparticle excitations and find that
our model can realize all the topological phases as the string-net model with
group $G=\prod_i G_i$. In this respect, our construction suggests several ways
of building lattice models which realize topological order $G$. They correspond
to intersecting string-net models with various choices of flavors of strings
associated with different decomposition of $G$. In fact, our construction
concretely demonstrates the K\text{\"u}nneth formula by constructing various
lattice models with the same topological order. As an example, we construct the
$G=\mathbb{Z}_2\times \mathbb{Z}_2 \times \mathbb{Z}_2 $ string-net model which
realizes a non-abelian topological phase by properly intersecting three copies
of toric codes.


title:
Categorical properties on the hyperspace of nontrivial convergent
  sequences

abstract:
  In this paper, we shall study categorial properties of the hyperspace of all
nontrivial convergent sequences $\mathcal{S}_c(X)$ of a Fre\'ech-Urysohn space
$X$, this hyperspace is equipped with the Vietoris topology. We mainly prove
that $\mathcal{S}_c(X)$ is meager whenever $X$ is a crowded space, as a
corollary we obtain that if $\mathcal{S}_c(X)$ is Baire, the $X$ has a dense
subset of isolated points. As an interesting example $\mathcal{S}_c(\omega_1)$
has the Baire property, where $\omega_1$ carries the order topology (this
answers a question from \cite{sal-yas}). We can give more examples like this
one by proving that the Alexandroff duplicated $\mathcal{A}(Z)$ of a space $Z$
satisfies that $\mathcal{S}_c(\mathcal{A}(Z))$ has the Baire property, whenever
$Z$ is a $\Sigma$-product of completely metrizable spaces and $Z$ is crowded.
Also we show that if $\mathcal{S}_c(X)$ is pseudocompact, then $X$ has a
relatively countably compact dense subset of isolated points, every finite
power of $X$ is pseudocompact, and every $G_\delta$-point in $X$ must be
isolated. We also establish several topological properties of the hyperspace of
nontrivial convergent sequences of countable Fre\'ech-Urysohn spaces with only
one non-isolated point.


title: Cardinality of the Ellis semigroup on compact metric countable spaces

abstract:
  Let $E(X,f)$ be the Ellis semigroup of a dynamical system $(X,f)$ where $X$
is a compact metric space. We analyze the cardinality of $E(X,f)$ for a compact
countable metric space $X$. A characterization when
  $E(X,f)$ and $E(X,f)^* = E(X,f) \setminus \{ f^n : n \in \mathbb{N}\}$ are
both finite is given. We show that if the collection of all periods of the
periodic points of $(X,f)$ is infinite, then $E(X,f)$ has size $2^{\aleph_0}$.
It is also proved that if $(X,f)$ has a point with a dense orbit and all
elements of $E(X,f)$ are continuous, then $|E(X,f)| \leq |X|$. For dynamical
systems of the form $(\omega^2 +1,f)$, we show that if there is a point with a
dense orbit, then all elements of $E(\omega^2+1,f)$ are continuous functions.
We present several examples of dynamical systems which have a point with a
dense orbit. Such systems provide examples where $E(\omega^2+1,f)$ and
$\omega^2+1$ are homeomorphic but not algebraically homeomorphic, where
$\omega^2+1$ is taken with the usual ordinal addition as semigroup operation.


title: Gauge-invariant perturbations of Schwarzschild spacetime

abstract:
  We study perturbations of Schwarzschild spacetime in a coordinate-free,
covariant form. The GHP formulation, having the advantage of not only being
covariant but also tetrad-rotation invariant, is used to write down the
previously known odd- and even-parity gauge-invariants and the equations they
satisfy. Additionally, in the even-parity sector, a new invariant and the
second order hyperbolic equation it satisfies are presented. Chandrasekhar's
work on transformations of solutions for perturbation equations on
Schwarzschild spacetime is translated into the GHP form, i.e., solutions for
the equations of the even- and odd-parity invariants are written in terms of
one another, and the extreme Weyl scalars; and solutions for the equations of
these latter invariants are also written in terms of one another. Recently,
further gauge invariants previously used by Steven Detweiler have been
described. His method is translated into GHP form and his basic invariants are
presented here. We also show how these invariants can be written in terms of
curvature invariants.


title: Identifying Significant Predictive Bias in Classifiers

abstract:
  We present a novel subset scan method to detect if a probabilistic binary
classifier has statistically significant bias -- over or under predicting the
risk -- for some subgroup, and identify the characteristics of this subgroup.
This form of model checking and goodness-of-fit test provides a way to
interpretably detect the presence of classifier bias or regions of poor
classifier fit. This allows consideration of not just subgroups of a priori
interest or small dimensions, but the space of all possible subgroups of
features. To address the difficulty of considering these exponentially many
possible subgroups, we use subset scan and parametric bootstrap-based methods.
Extending this method, we can penalize the complexity of the detected subgroup
and also identify subgroups with high classification errors. We demonstrate
these methods and find interesting results on the COMPAS crime recidivism and
credit delinquency data.


title: Global Testing Against Sparse Alternatives under Ising Models

abstract:
  In this paper, we study the effect of dependence on detecting sparse signals.
In particular, we focus on global testing against sparse alternatives for the
means of binary outcomes following an Ising model, and establish how the
interplay between the strength and sparsity of a signal determines its
detectability under various notions of dependence. The profound impact of
dependence is best illustrated under the Curie-Weiss model where we observe the
effect of a "thermodynamic" phase transition. In particular, the critical state
exhibits a subtle "blessing of dependence" phenomenon in that one can detect
much weaker signals at criticality than otherwise. Furthermore, we develop a
testing procedure that is broadly applicable to account for dependence and show
that it is asymptotically minimax optimal under fairly general regularity
conditions.


title:
Software-Defined Networking-based Crypto Ransomware Detection Using HTTP
  Traffic Characteristics

abstract:
  Ransomware is currently the key threat for individual as well as corporate
Internet users. Especially dangerous is crypto ransomware that encrypts
important user data and it is only possible to recover it once a ransom has
been paid. Therefore devising efficient and effective countermeasures is a
rising necessity. In this paper we present a novel Software-Defined Networking
(SDN) based detection approach that utilizes characteristics of ransomware
communication. Based on the observation of network communication of two crypto
ransomware families, namely CryptoWall and Locky we conclude that analysis of
the HTTP messages' sequences and their respective content sizes is enough to
detect such threats. We show feasibility of our approach by designing and
evaluating the proof-of-concept SDN-based detection system. Experimental
results confirm that the proposed approach is feasible and efficient.


title:
Electronic origin of structural transition in 122 Fe based
  superconductors

abstract:
  Direct quantitative correlations between the orbital order and
orthorhombicity is achieved in a number of Fe-based superconductors of 122
family. The former (orbital order) is calculated from first principles
simulations using experimentally determined doping and temperature dependent
structural parameters while the latter (the orthorhombicity) is taken from
already established experimental studies; when normalized, both the above
quantities quantitatively corresponds to each other in terms of their doping as
well as temperature variations. This proves that the structural transition in
Fe-based materials is electronic in nature due to orbital ordering. An
universal correlations among various structural parameters and electronic
structure are also obtained. Most remarkable among them is the mapping of two
Fe\--Fe distances in the low temperature orthorhombic phase, with the band
energies E$_{d_{xz}}$, E$_{d_{yz}}$ of Fe at the high symmetry points of the
Brillouin zone. The fractional co-ordinate $z_{As}$ of $As$ which essentially
determines anion height is inversely (directly) proportional to Fe-As bond
distances (with exceptions of K doped BaFe$_2$As$_2$) for hole (electron) doped
materials as a function of doping. On the other hand, Fe-As bond-distance is
found to be inversely (directly) proportional to the density of states at the
Fermi level for hole (electron) doped systems. Implications of these results to
current issues of Fe based superconductivity are discussed.


title: Non-unipotent representations and categorical centres

abstract:
  Let G be a connected reductive group defined over a finite field F_q. We give
a parametrization of the irreducible representations of G(F_q) in terms of
(twisted) categorical centres of various monoidal categories associated to G.
(Results of this type were known earlier for unipotent representations.
Analogous results for the parametrization of character sheaves on G were also
known earlier.)


title: Analytic definition of spin structure

abstract:
  We work on a parallelizable time-orientable Lorentzian 4-manifold and prove
that in this case the notion of spin structure can be equivalently defined in a
purely analytic fashion. Our analytic definition relies on the use of the
concept of a non-degenerate two-by-two formally self-adjoint first order linear
differential operator and gauge transformations of such operators. We also give
an analytic definition of spin structure for the 3-dimensional Riemannian case.


title:
Emergence of string-valence bond solid state in the frustrated $J_1-J_2$
  transverse field Ising model on the square lattice

abstract:
  We investigate the ground state nature of the transverse field Ising model on
the $J_1-J_2$ square lattice at the highly frustrated point $J_2/J_1=0.5$. At
zero field, the model has an exponentially large degenerate classical ground
state, which can be affected by quantum fluctuations for non-zero field toward
a unique quantum ground state. We consider two types of quantum fluctuations,
harmonic ones by using linear spin wave theory (LSWT) with single-spin flip
excitations above a long range magnetically ordered background and anharmonic
fluctuations, by employing a cluster-operator approach (COA) with multi-spin
cluster type fluctuations above a non-magnetic cluster ordered background. Our
findings reveal that the harmonic fluctuations of LSWT fail to lift the
extensive degeneracy as well as signaling a violation of the Hellmann-Feynman
theorem. However, the string-type anharmonic fluctuations of COA are able to
lift the degeneracy toward a string-valence bond solid (VBS) state, which is
obtained from an effective theory consistent with the Hellmann-Feynman theorem
as well. Our results are further confirmed by implementing numerical tree
tensor network simulation. The emergent non-magnetic string-VBS phase is gapped
and breaks lattice rotational symmetry with only two-fold degeneracy, which
bears a continuous quantum phase transition at $\Gamma/J_1 \cong 0.50$ to the
quantum paramagnet phase of high fields. The critical behavior is characterized
by $\nu \cong 1.0$ and $\gamma \cong 0.33$ exponents.


title: Confidence intervals for the current status model

abstract:
  We discuss a new way of constructing pointwise confidence intervals for the
distribution function in the current status model. The confidence intervals are
based on the smoothed maximum likelihood estimator (SMLE) and constructed using
bootstrap methods. Other methods to construct confidence intervals, using the
non-standard limit distribution of the (restricted) MLE, are compared to our
approach via simulations and real data applications.


title: Gaia and Variable Stars

abstract:
  We present a comparison of the Gaia DR1 samples of pulsating variable stars -
Cepheids and RR Lyrae type - with the OGLE Collection of Variable Stars aiming
at the characterization of the Gaia mission performance in the stellar
variability domain.
  Out of 575 Cepheids and 2322 RR Lyrae candidates from the Gaia DR1 samples
located in the OGLE footprint in the sky, 559 Cepheids and 2302 RR Lyrae stars
are genuine pulsators of these types. The number of misclassified stars is low
indicating reliable performance of the Gaia data pipeline.
  The completeness of the Gaia DR1 samples of Cepheids and RR Lyrae stars is at
the level of 60-75% as compared to the OGLE Collection dataset. This level of
completeness is moderate and may limit the applicability of the Gaia data in
many projects.


title:
Species with potential arising from surfaces with orbifold points of
  order 2, Part II: arbitrary weights

abstract:
  Let $\mathbf{\Sigma}=(\Sigma,M,O)$ be a surface with marked points and
order-2 orbifold points which is either unpunctured or once-punctured closed,
and $\omega:O\rightarrow\{1,4\}$ a function. For each triangulation $\tau$ of
$\mathbf{\Sigma}$ we construct a cochain complex $C^\bullet(\tau,\omega)$. A
colored triangulation is defined to be a pair consisting of a triangulation
$\tau$ and a 1-cocycle of $C^\bullet(\tau,\omega)$; the combinatorial notion of
colored flip of colored triangulations is then defined as a refinement of the
notion of flip of triangulations. Our main construction associates to each
colored triangulation a species and a potential, and our main result shows that
colored triangulations related by a colored flip have SPs related by the
corresponding SP-mutation.
  We define the flip graph of $(\Sigma,M,O,\omega)$, whose vertices are the
pairs $(\tau,x)$ with $\tau$ a triangulation and $x$ a cohomology class in
$H^1(C^\bullet(\tau,\omega))$, with an edge between $(\tau,x)$ and $(\sigma,z)$
iff $(\tau,\xi)$ and $(\sigma,\zeta)$ are related by a colored flip for some
cocycles $\xi$ and $\zeta$ respectively representing $x$ and $z$. We prove that
this graph is disconnected if $\Sigma$ is not contractible.
  For unpunctured surfaces we show that $(\tau,\xi)$ and $(\tau,\xi')$ yield
isomorphic Jacobian algebras if and only if $[\xi]=[\xi']$ in cohomology. We
prove that every SP-realization of any $(\tau,\omega)$ via a non-degenerate SP
over a cyclic Galois extension with certain roots of unity is right-equivalent
to one of the SPs we construct here.
  The species constructed here are species realizations of the $2^{|O|}$
skew-symmetrizable matrices assigned by Felikson-Shapiro-Tumarkin to any given
$\tau$. In the prequel to this paper we realized only one of these matrices via
species, but therein we allowed the presence of arbitrarily many punctures.


title: Scattering of wave packets with phases

abstract:
  A general problem of $2\rightarrow N_f$ scattering is addressed with all the
states being wave packets with arbitrary phases. Depending on these phases, one
deals with coherent states in $(3+1)$ D, vortex particles with orbital angular
momentum, the Airy beams, and their generalizations. A method is developed in
which a number of events represents a functional of the Wigner functions of
such states. Using width of a packet $\sigma_p/\langle p\rangle$ as a small
parameter, the Wigner functions, the number of events, and a cross section are
represented as power series in this parameter, the first non-vanishing
corrections to their plane-wave expressions are derived, and generalizations
for beams are made. Although in this regime the Wigner functions turn out to be
everywhere positive, the cross section develops new specifically quantum
features, inaccessible in the plane-wave approximation. Among them is
dependence on an impact parameter between the beams, on phases of the incoming
states, and on a phase of the scattering amplitude. A model-independent
analysis of these effects is made. Two ways of measuring how a Coulomb phase
and a hadronic one change with a transferred momentum $t$ are discussed.


title: Deep Watershed Transform for Instance Segmentation

abstract:
  Most contemporary approaches to instance segmentation use complex pipelines
involving conditional random fields, recurrent neural networks, object
proposals, or template matching schemes. In our paper, we present a simple yet
powerful end-to-end convolutional neural network to tackle this task. Our
approach combines intuitions from the classical watershed transform and modern
deep learning to produce an energy map of the image where object instances are
unambiguously represented as basins in the energy map. We then perform a cut at
a single energy level to directly yield connected components corresponding to
object instances. Our model more than doubles the performance of the
state-of-the-art on the challenging Cityscapes Instance Level Segmentation
task.


title:
Outflow and metallicity in the broad-line region of low-redshift active
  galactic nuclei

abstract:
  Outflows in active galactic nuclei (AGNs) are crucial to understand in
investigating the co-evolution of supermassive black holes (SMBHs) and their
host galaxies since outflows may play an important role as an AGN feedback
mechanism. Based on the archival UV spectra obtained with HST and IUE, we
investigate outflows in the broad-line region (BLR) in low-redshift AGNs (z <
0.4) through the detailed analysis of the velocity profile of the CIV emission
line. We find a dependence of the outflow strength on the Eddington ratio and
the BLR metallicity in our low-redshift AGN sample, which is consistent with
the earlier results obtained for high-redshift quasars. These results suggest
that the BLR outflows, gas accretion onto SMBH, and past star-formation
activity in the host galaxies are physically related in low-redshift AGNs as in
powerful high-redshift quasars.