title:
All-sky search for short gravitational-wave bursts in the first Advanced
  LIGO run

abstract:
  We present the results from an all-sky search for short-duration
gravitational waves in the data of the first run of the Advanced LIGO detectors
between September 2015 and January 2016. The search algorithms use minimal
assumptions on the signal morphology, so they are sensitive to a wide range of
sources emitting gravitational waves. The analyses target transient signals
with duration ranging from milliseconds to seconds over the frequency band of
32 to 4096 Hz. The first observed gravitational-wave event, GW150914, has been
detected with high confidence in this search; other known gravitational-wave
events fall below the search's sensitivity. Besides GW150914, all of the search
results are consistent with the expected rate of accidental noise coincidences.
Finally, we estimate rate-density limits for a broad range of non-BBH transient
gravitational-wave sources as a function of their gravitational radiation
emission energy and their characteristic frequency. These rate-density
upper-limits are stricter than those previously published by an
order-of-magnitude.


title:
Collisions of massive particles, timelike thin shells and formation of
  black holes in three dimensions

abstract:
  We study collisions of massive pointlike particles in three dimensional
anti-de Sitter space, generalizing the work on massless particles in [1]. We
show how to construct exact solutions corresponding to the formation of either
a black hole or a conical singularity from the collision of an arbitrary number
of massive particles that fall in radially and collide at the origin of AdS. No
restrictions on the masses or the angular and radial positions from where the
particles are released, are imposed. We also consider the limit of an infinite
number of particles, obtaining novel timelike thin shell spacetimes. These thin
shells have an arbitrary mass distribution as well as a non-trivial embedding
where the radial location of the shell depends on the angular coordinate, and
we analyze these shells using the junction formalism of general relativity. We
also consider the massless limit and find consistency with earlier results, as
well as comment on the stress-energy tensor modes of the dual CFT.


title:
On a problem of dark matter: A centrally symmetric distribution of a
  pseudoscalar field in the general relativity

abstract:
  A precise solution of the general relativity equations for centrally
symmetric distribution of a pseudoscalar field with U(1) symmetry is presented.
It is found that energy density of the field is restricted in the symmetry
center and falls with radial distance at a much slower rate than in numerical
simulations of dark matter haloes. This result can solve the cusp problem for
galaxies and the problem of rotation curves for galaxy exteriors.


title:
Non-local meta-conformal invariance, diffusion-limited erosion and the
  XXZ chain

abstract:
  Diffusion-limited erosion is a distinct universality class of fluctuating
interfaces. Although its dynamical exponent $z=1$, none of the known variants
of conformal invariance can act as its dynamical symmetry. In $d=1$ spatial
dimensions, its infinite-dimensional dynamic symmetry is constructed and shown
to be isomorphic to the direct sum of three loop-Virasoro algebras, with the
maximal finite-dimensional sub-algebra
$\mathfrak{sl}(2,\mathbb{R})\oplus\mathfrak{sl}(2,\mathbb{R})\oplus\mathfrak{sl}(2,\mathbb{R})$.
The infinitesimal generators are spatially non-local and use the Riesz-Feller
fractional derivative. Co-variant two-time response functions are derived and
reproduce the exact solution of diffusion-limited erosion. The relationship
with the terrace-step-kind model of vicinal surfaces and the integrable XXZ
chain are discussed.

categories: cond-mat.stat-mech hep-th math-ph math.MP nlin.SI


title:
The Feynman-Dyson Propagators for Neutral Particles (Locality or
  Non-locality?)

abstract:
  An analog of the S=1/2 Feynman-Dyson propagator is presented in the framework
of the S=1 Weinberg theory. The basis for this construction is the concept of
the Weinberg field as a system of four field functions differing by parity and
by dual transformations. Next, we analyze the recent controversy in the
definitions of the Feynman-Dyson propagator for the field operator containing
the S=1/2 self/anti-self charge conjugate states in the papers by D. Ahluwalia
et al. and by W. Rodrigues Jr. et al. The solution of this mathematical
controversy is obvious. It is related to the necessary doubling of the Fock
Space (as in the Barut and Ziino works), thus extending the corresponding
Clifford Algebra. However, the logical interrelations of different mathematical
foundations with the physical interpretations are not so obvious. Physics
should choose only one correct formalism, it is not clear, why two correct
mathematical formalisms (which are based on the same postulates) lead to
different physical results?


title: Toward a classification of semidegenerate 3D superintegrable systems

abstract:
  Superintegrable systems of 2nd order in 3 dimensions with exactly 3-parameter
potentials are intriguing objects. Next to the nondegenerate 4-parameter
potential systems they admit the maximum number of symmetry operators but their
symmetry algebras don't close under commutation and not enough is known about
their structure to give a complete classification. Some examples are known for
which the 3-parameter system can be extended to a 4th order superintegrable
system with a 4-parameter potential and 6 linearly independent symmetry
generators. In this paper we use B\^ocher contractions of the conformal Lie
algebra $so(5,C)$ to itself to generate a large family of 3-parameter systems
with 4th order extensions, on a variety of manifolds, and all from B\^ocher
contractions of a single "generic" system on the 3-sphere. We give a
contraction scheme relating these systems. The results have myriad applications
for finding explicit solutions for both quantum and classical systems.


title: Evaluating Gaussian processes for sparse irregular spatio-temporal data

abstract:
  A practical approach to evaluate performance of a Gaussian process regression
models (GPR) for irregularly sampled sparse time-series is introduced. The
approach entails construction of a secondary autoregressive model using the
fine scale predictions to forecast a future observation used in GPR. We build
different GPR models for Ornstein-Uhlenbeck and Fractional processes for
simulated toy data with different sparsity levels to assess the utility of the
approach.


title:
On the Iterations of a Sequence of Strongly Quasi-nonexpansive Mappings
  with Applications

abstract:
  In this paper, we study $\Delta$- convergence of iterations for a sequence of
strongly quasi-nonexpansive mappings as well as the strong convergence of the
Halpern type regularization of them in Hadamard spaces. Then, we give some
their applications in iterative methods, convex and pseudo-convex
minimization(proximal point algorithm), fixed point theory and equilibrium
problems. The results extend several new results in the literature and some of
them seem new even in Hilbert spaces.


title: Semantics of Information

abstract:
  Due to the self-referencing aspect, consciousness is placed in a unique
non-computable position among natural phenomena. Non-computable consciousness
was previously analyzed on the basis of self-referential cyclical time. This
paper extends the cyclical model of vacuum observation and posits that choice,
or the experience of reality, may be expressed as the initial part of the
self-referencing loop, while the conscious awareness of the experience is the
other part of the loop. In particular, the inseparability of the two sides of
the loop is established through the cyclical time process, which bears a
resemblance to Heidegger's analysis of existence. The cyclical looping model is
also discussed in terms of Wittgenstein's analysis of language as attaching
semantic meaning, or continuous or infinite conscious awareness, to physical
reality. We also discuss the proposed model of subjectivity and cyclical time -
as opposed to objectivity and linear time - which may be considered similar to
Hebrew thought.


title: Noncommutative functional calculate and its application

abstract:
  In this paper we construct an unitary operator $F_{xx*}$ such that
$(F_{xx^{*}})^2=identity$ and $Fix(F_{xx^*})\neq\emptyset$. We get the unitary
equivalent representations $F_{xx*}(M_{z\psi(z)}-a)$ on
$\mathcal{L}^{2}(\sigma(|T+a|),\mu_{|T+a|})$ for any given
$T\in\mathcal{B}(\mathbb{H})$, where
$\psi(z)\in\mathcal{L}^{\infty}(\sigma(|T+a|),\mu_{|T+a|})$, $a\in\rho(T)$,
$F_{xx*}(f(xx^*))=f(x^*x)$, $\mathcal{B}(\mathbb{H})$ is the set of all bounded
linear operator on complex separable Hilbert space $\mathbb{H}$. Also, we get
that if $z\psi(z)\in Fix(F_{xx^*})$, then $T$ has a nontrivial invariant
subspace space on $\mathbb{H}$ which has dimension $>1$. Moreover, we define
the Lebesgue class
$\mathcal{B}_{Leb}(\mathbb{H})\subset\mathcal{B}(\mathbb{H})$ and get that if
$T$ is a Lebesgue operator, then $T$ is Li-Yorke chaotic if and only if
$T^{*-1}$ is.


title: AdS$_5$ vacua from type IIB supergravity on $T^{1,1}$

abstract:
  We study maximally supersymmetric Anti-de Sitter backgrounds in consistent
N=2 truncations of type IIB supergravity compactified on the Sasaki-Einstein
manifold $T^{1,1}$. In particular, we focus on truncations that contain fields
coming from the nontrivial second and third cohomology forms on $T^{1,1}$.
These give rise to N=2 supergravity coupled to two vector- and two
hypermultiplets (Betti-vector truncation) or one vector- and three
hypermultiplets (Betti-hyper truncation), respectively. We find that both
truncations admit AdS$_5$ backgrounds with the gauge group always being broken
but containing at least an $U(1)_R$ factor. Moreover, in both cases we show
that the moduli space of AdS vacua is nontrivial and of maximal dimension.
Finally, we explicitly compute the metrics on these moduli spaces.


title: Fixed Points of Augmented Generalized Happy Functions

abstract:
  An augmented generalized happy function $S_{[c,b]}$ maps a positive integer
to the sum of the squares of its base $b$ digits plus $c$. In this paper, we
study various properties of the fixed points of $S_{[c,b]}$; count the number
of fixed points of $\S_{[c,b]}$, for $b \geq 2$ and $0<c<3b-3$; and prove that,
for each $b \geq 2$, there exist arbitrarily many consecutive values of $c$ for
which $S_{[c,b]}$ has no fixed point.


title: Search For Type Ia Supernova NUV-Optical Subclasses

abstract:
  In response to a recently reported observation of evidence for two classes of
Type Ia Supernovae (SNe Ia) distinguished by their brightness in the rest-frame
near ultraviolet (NUV), we search for the phenomenon in publicly available
light-curve data. We use the SNANA supernova analysis package to simulate SN
Ia-light curves in the Sloan Digital Sky Survey Supernova Search (SDSS) and the
Supernova Legacy Survey (SNLS) with a model of two distinct ultraviolet classes
of SNe Ia and a conventional model with a single broad distribution of SN-Ia
ultraviolet brightnesses. We compare simulated distributions of rest-frame
colors with these two models to those observed in 158 SNe Ia in the SDSS and
SNLS data. The SNLS sample of 99 SNe Ia is in clearly better agreement with a
model with one class of SN Ia light curves and shows no evidence for distinct
NUV sub-classes. The SDSS sample of 59 SNe Ia with poorer color resolution does
not distinguish between the two models.


title:
Production of charmed baryons in $\bar p p$ collisions close to their
  thresholds

abstract:
  Cross sections for the charm-production reactions $\bar p p \to \bar
\Lambda_c^- \Sigma_c^+$, $\bar \Sigma_c\Sigma_c$, $\bar \Xi_c\Xi_c$, and $\bar
\Xi_c'\Xi_c'$ are presented, for energies near their respective thresholds. The
results are based on a calculation performed in the meson-exchange framework in
close analogy to earlier studies of the J\"ulich group on the
strangeness-production reactions $\bar p p \to \bar \Lambda\Sigma$, $\bar
\Sigma\Sigma$, $\bar \Xi\Xi$ by connecting the two sectors via SU(4) flavor
symmetry. The cross sections are found to be in the order of $0.1 - 1$ $\mu b$
at energies of $100$ MeV above the respective thresholds, for all considered
channels. Complementary to meson-exchange, where the charmed baryons are
produced by the exchange of $D$ and $D^*$ mesons, a charm-production potential
derived in a quark model is employed for assessing uncertainties. The cross
sections predicted within that picture turned out to be significantly smaller.


title: Gamma-Rays from Non-Blazar AGN

abstract:
  Non-blazar Active Galactic Nuclei (AGN) have emerged as a new gamma-ray
emitting source class on the extragalactic sky and started to deepen our
understanding of the physical processes and the nature of AGN in general. The
detection of Narrow Line Seyfert 1 galaxies in the Fermi-LAT energy regime, for
example, offers important information for our understanding of jet formation
and radio-loudness. Radio galaxies, on the other hand, have become particularly
interesting at high (HE) and very high (VHE) gamma-ray energies. With their
jets not directly pointing towards us (i.e. misaligned), they offer a unique
tool to probe into the nature of the fundamental (and often hidden) physical
processes in AGN. This review highlights and discusses some of the
observational and theoretical progress achieved in the gamma-ray regime during
recent years, including the evidence for unexpected spectral hardening in
Centaurus A and extreme short-term variability as seen in IC 310 and M87.


title:
Reducing phase singularities in speckle interferometry by coherence
  tailoring

abstract:
  Speckle interferometry is an established optical metrology tool for the
characterization of rough objects. The raw phase, however, is impaired by the
presence of phase singularities, making the unwrapping procedure ambiguous. In
a Michelson setup, we tailor the spatial coherence of the light source,
achieving a physical averaging of independent, mutually incoherent speckle
fields. In the resulting raw phase, the systematic phase is preserved while the
number of phase singularities is greatly reduced. Both interferometer arms are
affected by the averaging. The reduction is sufficient to even allow the use of
a standard unwrapping algorithm originally developed for smooth surfaces only.


title: Distant supervision for emotion detection using Facebook reactions

abstract:
  We exploit the Facebook reaction feature in a distant supervised fashion to
train a support vector machine classifier for emotion detection, using several
feature combinations and combining different Facebook pages. We test our models
on existing benchmarks for emotion detection and show that employing only
information that is derived completely automatically, thus without relying on
any handcrafted lexicon as it's usually done, we can achieve competitive
results. The results also show that there is large room for improvement,
especially by gearing the collection of Facebook pages, with a view to the
target domain.


title: Bayesian data assimilation based on a family of outer measures

abstract:
  A flexible representation of uncertainty that remains within the standard
framework of probabilistic measure theory is presented along with a study of
its properties. This representation relies on a specific type of outer measure
that is based on the measure of a supremum, hence combining additive and highly
sub-additive components. It is shown that this type of outer measure enables
the introduction of intuitive concepts such as pullback and general data
assimilation operations.


title: Non-Equilibrium Markov State Modeling of the Globule-Stretch Transition

abstract:
  We describe a systematic approach to construct coarse-grained Markov state
models from molecular dynamics data of systems driven into a non-equilibrium
steady state. We apply this method to study the globule-stretch transition of a
single tethered model polymer in shear flow. The folding/unfolding rates of the
coarse-grained model agree with the original detailed model. We demonstrate
that the folding/unfolding proceeds through the same narrow region of
configuration space but along different cycles.


title: Quantum walk transport properties on graphene structures

abstract:
  We present numerical studies of quantum walks on \C60 and related graphene
structures, to investigate their transport properties. Also known as a
\emph{honeycomb lattice}, the lattice formed by carbon atoms in the graphene
phase can be rolled up to form nanotubes of various dimensions. Graphene
nanotubes have many important applications, some of which rely on their unusual
electrical conductivity and related properties. Quantum walks on graphs provide
an abstract setting in which to study such transport properties independent of
the other chemical and physical properties of a physical substance. They can
thus be used to further the understanding of mechanisms behind such properties.
We find that nanotube structures are significantly more efficient in
transporting a quantum walk than cycles of equivalent size, provided the
symmetry of the structure is respected in how they are used. We find faster
transport on zig-zag nanotubes compared to armchair nanotubes, which is
unexpected given that for the actual materials the armchair nanotube is
metallic, while the zig-zag is semiconducting.


title: Authority-based Team Discovery in Social Networks

abstract:
  Given a social network of experts, we address the problem of discovering a
team of experts that collectively holds a set of skills required to complete a
given project. Most prior work ranks possible solutions by communication cost,
represented by edge weights in the expert network. Our contribution is to take
experts authority into account, represented by node weights. We formulate
several problems that combine communication cost and authority, we prove that
they are NP-hard, and we propose and experimentally evaluate greedy algorithms
to solve them.


title:
Solution Theory, Variational Formulations, and Functional A Posteriori
  Error Estimates for General First Order Systems with Applications to
  Electro-Magneto-Statics and More

abstract:
  We prove a comprehensive solution theory using tools from functional
analysis, show corresponding variational formulations, and present functional a
posteriori error estimates for general linear first order systems. As a
prototypical application we will discuss the system of electro-magneto statics
with mixed tangential and normal boundary conditions. Second order systems will
be considered as well.


title: On the Ascoli property for locally convex spaces and topological groups

abstract:
  We characterize Ascoli spaces by showing that a Tychonoff space $X$ is Ascoli
iff the canonical map from the free locally convex space $L(X)$ over $X$ into
$C_k\big(C_k(X)\big)$ is an embedding of locally convex spaces. We prove that
an uncountable direct sum of non-trivial locally convex spaces is not Ascoli.
If a $c_0$-barrelled space $X$ is weakly Ascoli, then $X$ is linearly
isomorphic to a dense subspace of $\mathbb{R}^\Gamma$ for some $\Gamma$.
Consequently, a Fr\'{e}chet space $E$ is weakly Ascoli iff $E=\mathbb{R}^N$ for
some $N\leq\omega$. If $X$ is a $\mu$-space and a $k$-space (for example,
metrizable), then $C_k(X)$ is weakly Ascoli iff $X$ is discrete. We prove that
the weak* dual space of a Banach space $E$ is Ascoli iff $E$ is
finite-dimensional.


title:
Discovery of a new accreting millisecond X-ray pulsar in the globular
  cluster NGC 2808

abstract:
  We report on the discovery of coherent pulsations at a period of 2.9 ms from
the X-ray transient MAXI J0911-655 in the globular cluster NGC 2808. We
observed X-ray pulsations at a frequency of $\sim339.97$ Hz in three different
observations of the source performed with XMM-Newton and NuSTAR during the
source outburst. This newly discovered accreting millisecond pulsar is part of
an ultra-compact binary system characterised by an orbital period of $44.3$
minutes and a projected semi-major axis of $\sim17.6$ lt-ms. Based on the mass
function we estimate a minimum companion mass of 0.024 M$_{\odot}$, which
assumes a neutron star mass of 1.4 M$_{\odot}$ and a maximum inclination angle
of $75^{\circ}$ (derived from the lack of eclipses and dips in the light-curve
of the source). We find that the companion star's Roche-Lobe could either be
filled by a hot ($5\times 10^{6}$ K) pure helium white dwarf with a 0.028
M$_{\odot}$ mass (implying $i\simeq58^{\circ}$) or an old (>5 Gyr) brown dwarf
with metallicity abundances between solar/sub-solar and mass ranging in the
interval 0.065$-$0.085 M$_{\odot}$ (16 < $i$ < 21). During the outburst the
broad-band energy spectra are well described by a superposition of a weak
black-body component (kT$\sim$ 0.5 keV) and a hard cutoff power-law with photon
index $\Gamma \sim$ 1.7 and cut-off at a temperature kT$_e\sim$ 130 keV. Up to
the latest Swift-XRT observation performed on 2016 July 19 the source has been
observed in outburst for almost 150 days, which makes MAXI J0911-655 the second
accreting millisecond X-ray pulsar with outburst duration longer than 100 days.


title:
A first-principles model of copper-boron interactions in Si:
  implications for the light-induced degradation of solar Si

abstract:
  The recent discovery that Cu contamination of Si combined with light exposure
has a significant detrimental impact on carrier life-time has drawn much
concern within the solar-Si community. The effect, known as the copper-related
light-induced degradation (Cu-LID) of Si solar cells, has been connected to the
release of Cu interstitials within the bulk [Solar Energy Materials & Solar
Cells, 147:115-126, 2016]. In this paper, we describe a comprehensive analysis
of the formation/dissociation process of the CuB pair in Si by means of
first-principles modelling, as well as the interaction of CuB defects with
photo-excited minority carriers. We confirm that the long-range interaction
between the Cu cation and the B anion has a Coulomb-like behaviour, in line
with the trapping-limited diffusivity of Cu observed by transient ion drift
measurements. On the other hand, the short-range interaction between the
d-electrons of Cu and the excess of negative charge on B produces a repulsive
effect, thereby decreasing the binding energy of the pair when compared to the
ideal point-charge Coulomb model. We also find that metastable CuB pairs
produce acceptor states just below the conduction band minimum, which arise
from the Cu level emptied by the B acceptor. Based on these results, we argue
that photo-generated minority carriers trapped by the metastable pairs can
switch off the Coulomb interaction that holds the pairs together, enhancing the
release of Cu interstitials, and acting as a catalyst for Cu-LID.


title: Optimal quantum interference thermoelectric heat engine with edge states

abstract:
  We show theoretically that a thermoelectric heat engine, operating
exclusively due to quantum-mechanical interference, can reach optimal
linear-response performance. A chiral edge state implementation of a
close-to-optimal heat engine is proposed in an electronic Mach-Zehnder
interferometer with a mesoscopic capacitor coupled to one arm. We demonstrate
that the maximum power and corresponding efficiency can reach 90\% and 83\%,
respectively, of the theoretical maximum. The proposed heat engine can be
realized with existing experimental techniques and has a performance robust
against moderate dephasing.


title: On the $L_r$-operators penalized by $(r+1)$-mean curvature

abstract:
  In this paper, we establish the non-positivity of the second eigenvalue of
the Schr\"odinger operator $-\textrm{div}\big( P_r \nabla\cdot\big) - W_r^2$ on
a closed hypersurface $\Sigma^n$ of $\mathbb{R}^{n+1}$, where $W_r$ is a power
of the $(r+1)$-th mean curvature of $\Sigma^n$. In the case that this
eigenvalue is null we have a characterization of the sphere. This generalizes a
result of Evans and Loss proved for the Laplace-Beltrame operator penalized by
the square of the mean curvature.


title: Hydrodynamic interactions between nearby slender filaments

abstract:
  Cellular biology abound with filaments interacting through fluids, from
intracellular microtubules, to rotating flagella and beating cilia. While
previous work has demonstrated the complexity of capturing nonlocal
hydrodynamic interactions between moving filaments, the problem remains
difficult theoretically. We show here that when filaments are closer to each
other than their relevant length scale, the integration of hydrodynamic
interactions can be approximately carried out analytically. This leads to a set
of simplified local equations, illustrated on a simple model of two interacting
filaments, which can be used to tackle theoretically a range of problems in
biology and physics.


title:
Bio-Inspired Spiking Convolutional Neural Network using Layer-wise
  Sparse Coding and STDP Learning

abstract:
  Hierarchical feature discovery using non-spiking convolutional neural
networks (CNNs) has attracted much recent interest in machine learning and
computer vision. However, it is still not well understood how to create a
biologically plausible network of brain-like, spiking neurons with multi-layer,
unsupervised learning. This paper explores a novel bio-inspired spiking CNN
that is trained in a greedy, layer-wise fashion. The proposed network consists
of a spiking convolutional-pooling layer followed by a feature discovery layer
extracting independent visual features. Kernels for the convolutional layer are
trained using local learning. The learning is implemented using a sparse,
spiking auto-encoder representing primary visual features. The feature
discovery layer extracts independent features by probabilistic, leaky
integrate-and-fire (LIF) neurons that are sparsely active in response to
stimuli. The layer of the probabilistic, LIF neurons implicitly provides
lateral inhibitions to extract sparse and independent features. Experimental
results show that the convolutional layer is stack-admissible, enabling it to
support a multi-layer learning. The visual features obtained from the proposed
probabilistic LIF neurons in the feature discovery layer are utilized for
training a classifier. Classification results contribute to the independent and
informative visual features extracted in a hierarchy of convolutional and
feature discovery layers. The proposed model is evaluated on the MNIST digit
dataset using clean and noisy images. The recognition performance for clean
images is above 98%. The performance loss for recognizing the noisy images is
in the range 0.1% to 8.5% depending on noise types and densities. This level of
performance loss indicates that the network is robust to additive noise.


title: On Lang's conjecture for some product-quotient surfaces

abstract:
  We prove effective versions of algebraic and analytic Lang's conjectures for
product-quotient surfaces of general type with $P_g=0$ and $c_1^2=c_2$.


title:
W and Z boson production in p-Pb collisions at $\sqrt{s_{\rm NN}}$ =
  5.02 TeV

abstract:
  The W and Z boson production was measured via the muonic decay channel in
proton-lead collisions at $\sqrt{s_{\rm NN}} = 5.02$ TeV at the Large Hadron
Collider with the ALICE detector. The measurement covers backward ($-4.46 <
y_{\rm cms} < -2.96$) and forward ($2.03 < y_{\rm cms} < 3.53$) rapidity
regions, corresponding to Pb-going and p-going directions, respectively. The
Z-boson production cross section, with dimuon invariant mass of
$60<m_{\mu\mu}<120$ GeV/$c^2$ and muon transverse momentum ($p_{\rm T}^\mu$)
larger than 20 GeV/$c$, is measured. The production cross section and charge
asymmetry of muons from W-boson decays with $p_{\rm T}^\mu>10$ GeV/$c$ are
determined. The results are compared to theoretical calculations both with and
without including the nuclear modification of the parton distribution
functions. The W-boson production is also studied as a function of the
collision centrality: the cross section of muons from W-boson decays is found
to scale with the average number of binary nucleon-nucleon collisions within
uncertainties.


title: sPHENIX: The next generation heavy ion detector at RHIC

abstract:
  sPHENIX is a new collaboration and future detector project at Brookhaven
National Laboratory's Relativistic Heavy Ion Collider (RHIC). It seeks to
answer fundamental questions on the nature of the quark gluon plasma (QGP),
including its temperature dependence and coupling strength, by using a suite of
precision jet and upsilon measurements that probe different length scales of
the QGP. This will be achieved with large acceptance, $|\eta| < 1$ and
$0$-$2\pi$ in $\phi$, electromagentic and hadronic calorimeters and precision
tracking enabled by a $1.5$ T superconducting magnet. With the increased
luminosity afforded by accelerator upgrades, sPHENIX will perform high
statistics measurements extending the kinematic reach at RHIC to overlap the
LHC's. This overlap with the LHC will facilitate better understanding of the
role of temperature, density and parton virtuality in QGP dynamics and for jet
quenching in particular. This talk will focus on key future measurements and
the current state of the sPHENIX project.


title: Differentiable equisingularity of holomorphic foliations

abstract:
  We prove that a $C^{\infty}$ equivalence between germs holomorphic foliations
at $({\mathbb C}^2,0)$ establishes a bijection between the sets of formal
separatrices preserving equisingularity classes. As a consequence, if one of
the foliations is of second type, so is the other and they are equisingular.


title:
Sensitivity of small myosin II ensembles from different isoforms to
  mechanical load and ATP concentration

abstract:
  Based on a detailed crossbridge model for individual myosin II motors, we
systematically study the influence of mechanical load and adenosine
triphosphate (ATP) concentration on small myosin II ensembles made from
different isoforms. For skeletal and smooth muscle myosin II, which are often
used in actomyosin gels that reconstitute cell contractility, fast forward
movement is restricted to a small region of phase space with low mechanical
load and high ATP concentration, which is also characterized by frequent
ensemble detachment. At high load, these ensembles are stalled or move
backwards, but forward motion can be restored by decreasing ATP concentration.
In contrast, small ensembles of nonmuscle myosin II isoforms, which are found
in the cytoskeleton of nonmuscle cells, are hardly affected by ATP
concentration due to the slow kinetics of the bound states. For all isoforms,
the thermodynamic efficiency of ensemble movement increases with decreasing ATP
concentration, but this effect is weaker for the nonmuscle myosin II isoforms.


title: Privacy-Preserving Genetic Relatedness Test

abstract:
  An increasing number of individuals are turning to Direct-To-Consumer (DTC)
genetic testing to learn about their predisposition to diseases, traits, and/or
ancestry. DTC companies like 23andme and Ancestry.com have started to offer
popular and affordable ancestry and genealogy tests, with services allowing
users to find unknown relatives and long-distant cousins. Naturally, access and
possible dissemination of genetic data prompts serious privacy concerns, thus
motivating the need to design efficient primitives supporting private genetic
tests. In this paper, we present an effective protocol for privacy-preserving
genetic relatedness test (PPGRT), enabling a cloud server to run relatedness
tests on input an encrypted genetic database and a test facility's encrypted
genetic sample. We reduce the test to a data matching problem and perform it,
privately, using searchable encryption. Finally, a performance evaluation of
hamming distance based PP-GRT attests to the practicality of our proposals.


title: The Higgs singlet extension at LHC Run 2

abstract:
  We discuss the current status of theoretical and experimental constraints on
the real Higgs singlet extension of the Standard Model. For the second neutral
(non-standard) Higgs boson the full mass range from 1 GeV to 1 TeV accessible
at past and current collider experiments is considered. We present benchmark
scenarios for searches for an additional Higgs state in the real Higgs singlet
extension of the Standard Model in Run 2 of the LHC. We furthermore discuss
electroweak corrections to the H to hh partial decay width within this model.


title: Stratification for the singular set of approximate harmonic maps

abstract:
  The aim of this note is to extend the results in arXiv:1504.02043 to the case
of approximate harmonic maps. More precisely, we will proved that the singular
strata $S^k(u)$ of an approximate harmonic map are k-rectifiable, and we will
show effect bounds on the quantitative strata. In the process we will simplify
many of the arguments from arXiv:1504.02043, and in particular we produce a new
main covering lemmas which vastly simplifies the older argument.


title: On distance in total variation between image measures

abstract:
  We are interested in the estimation of the distance in total variation $$
\Delta := \|P_{f(X)} - P_{g(X)}\|_{\mathrm var} $$ between distributions of
random variables $f(X)$ and $g(X)$ in terms of proximity of $f$ and $g.$ We
propose a simple general method of estimating $\Delta$. For Gaussian and
trigonometrical polynomials it gives an asymptotically optimal result (when the
degree tends to $\infty$).


title:
Population processes with unbounded extinction rate conditioned to
  non-extinction

abstract:
  This article studies the quasi-stationary behaviour of population processes
with unbounded absorption rate, including one-dimensional birth and death
processes with catastrophes and multi-dimensional birth and death processes,
modeling biological populations in interaction. To handle this situation, we
develop original non-linear Lyapunov criteria. We obtain the exponential
convergence in total variation of the conditional distributions to a unique
quasi-stationary distribution, uniformly with respect to the initial
distribution. Our results cover all one-dimensional birth and death processes
which come down from infinity with catastrophe rate satisfying appropriate
bounds, and multi-dimensional birth and death models with stronger
intra-specific than inter-specific competition.


title:
Dimension reduction for the Landau-de Gennes model on curved nematic
  thin films

abstract:
  We use the method of $\Gamma$-convergence to study the behavior of the
Landau-de Gennes model for a nematic liquid crystalline film attached to a
general fixed surface in the limit of vanishing thickness. This paper
generalizes the approach that we used previously to study a similar problem for
a planar surface. Since the anchoring energy dominates when the thickness of
the film is small, it is essential to understand its influence on the structure
of the minimizers of the limiting energy. In particular, the anchoring energy
dictates the class of admissible competitors and the structure of the limiting
problem. We assume general weak anchoring conditions on the top and the bottom
surfaces of the film and strong Dirichlet boundary conditions on the lateral
boundary of the film when the surface is not closed. We establish a general
convergence result to an energy defined on the surface that involves a somewhat
surprising remnant of the normal component of the tensor gradient. Then we
exhibit one effect of curvature through an analysis of the behavior of
minimizers to the limiting problem when the substrate is a frustrum.


title: New CRT sequence sets for a collision channel without feedback

abstract:
  Protocol sequences are binary and periodic sequences used for deterministic
multiple access in a collision channel without feedback. In this paper, we
focus on user-irrepressible (UI) protocol sequences that can guarantee a
positive individual throughput per sequence period with probability one for a
slot-synchronous channel, regardless of the delay offsets among the users. As
the sequence period has a fundamental impact on the worst-case channel access
delay, a common objective of designing UI sequences is to make the sequence
period as short as possible. Consider a communication channel that is shared by
$M$ active users, and assume that each protocol sequence has a constant Hamming
weight $w$. To attain a better delay performance than previously known UI
sequences, this paper presents a CRTm construction of UI sequences with
$w=M+1$, which is a variation of the previously known CRT construction. For all
non-prime $M\geq 8$, our construction produces the shortest known sequence
period and the shortest known worst-case delay of UI sequences. Numerical
results show that the new construction enjoys a better average delay
performance than the optimal random access scheme and other constructions with
the same sequence period, in a variety of traffic conditions. In addition, we
derive an asymptotic lower bound on the minimum sequence period for $w=M+1$ if
the sequence structure satisfies some technical conditions, called
equi-difference, and prove the tightness of this lower bound by using the CRTm
construction.


title: Long-term variability of T Tauri stars using WASP

abstract:
  We present a reference study of the long-term optical variability of young
stars using data from the WASP project. Our primary sample is a group of
well-studied classical T Tauri stars (CTTS), mostly in Taurus-Auriga. WASP
lightcurves cover timescales up to 7 years and typically contain 10000-30000
datapoints. We quantify the variability as function of timescale using the
time-dependent standard deviation 'pooled sigma'. We find that the overwhelming
majority of CTTS has low-level variability with sigma<0.3mag dominated by
timescales of a few weeks, consistent with rotational modulation. Thus, for
most young stars monitoring over a month is sufficient to constrain the total
amount of variability over timescales up to a decade. The fraction of stars
with strong optical variability (sigma>0.3mag) is 21% in our sample and 21% in
an unbiased control sample. An even smaller fraction (13% in our sample, 6% in
the control) show evidence for an increase in variability amplitude as a
function of timescale from weeks to months or years. The presence of long-term
variability correlates with the spectral slope at 3-5mu, which is an indicator
of inner disk geometry, and with the U-B band slope, which is an accretion
diagnostics. This shows that the long-term variations in CTTS are predominantly
driven by processes in the inner disk and in the accretion zone. Four of the
stars with long-term variations show periods of 20-60d, significantly longer
than the rotation periods and stable over months to years. One possible
explanation are cyclic changes in the interaction between the disk and the
stellar magnetic field.


title:
Energy and Bursty Packet Loss Tradeoff over Fading Channels: A System
  Level Model

abstract:
  Energy efficiency and quality of service (QoS) guarantees are the key design
goals for the 5G wireless communication systems. In this context, we discuss a
multiuser scheduling scheme over fading channels for loss tolerant
applications. The loss tolerance of the application is characterized in terms
of different parameters that contribute to quality of experience for the
application. The mobile users are scheduled opportunistically such that a
minimum QoS is guaranteed. We propose an opportunistic scheduling scheme and
address the cross layer design framework when channel state information is not
perfectly available at the transmitter and the receiver. We characterize the
system energy as a function of different QoS and channel state estimation error
parameters. The optimization problem is formulated using Markov chain framework
and solved using stochastic optimization techniques. The results demonstrate
that the parameters characterizing the packet loss are tightly coupled and
relaxation of one parameter does not benefit the system much if the other
constraints are tight. We evaluate the energy-performance trade-off numerically
and show the effect of channel uncertainty on the packet scheduler design.


title:
Honest Confidence Sets in Nonparametric IV Regression and Other
  Ill-Posed Models

abstract:
  This paper develops inferential methods for a very general class of ill-posed
models in econometrics encompassing the nonparametric instrumental variable
regression, various functional regressions, and the density deconvolution. We
focus on uniform confidence sets for the parameter of interest estimated with
Tikhonov regularization, as in Darolles, Fan, Florens, and Renault (2011).
Since it is impossible to have inferential methods based on the central limit
theorem, we develop two alternative approaches relying on the concentration
inequality and bootstrap approximations. We show that expected diameters and
coverage properties of resulting sets have uniform validity over a large class
of models, i.e., constructed confidence sets are honest. Monte Carlo
experiments illustrate that introduced confidence sets have reasonable width
and coverage properties. Using U.S. data, we provide uniform confidence sets
for Engel curves for various commodities.


title:
Probabilistic Caching in Wireless D2D Networks: Cache Hit Optimal vs.
  Throughput Optimal

abstract:
  Departing from the conventional cache hit optimization in cache-enabled
wireless networks, we consider an alternative optimization approach for the
probabilistic caching placement in stochastic wireless D2D caching networks
taking into account the reliability of D2D transmissions. Using tools from
stochastic geometry, we provide a closed-form approximation of cache-aided
throughput, which measures the density of successfully served requests by local
device caches, and we obtain the optimal caching probabilities with numerical
optimization. Compared to the cache-hit-optimal case, the optimal caching
probabilities obtained by cache-aided throughput optimization show notable gain
in terms of the density of successfully served user requests, particularly in
dense user environments.


title:
Singularities of metrics on Hodge bundles and their topological
  invariants

abstract:
  We consider degenerations of complex projective Calabi--Yau varieties and
study the singularities of $L^2$, Quillen and BCOV metrics on Hodge and
determinant bundles. The dominant and subdominant terms in the expansions of
the metrics close to non-smooth fibers are shown to be related to well-known
topological invariants of singularities, such as limit Hodge structures,
vanishing cycles and log-canonical thresholds. We also describe corresponding
invariants for more general degenerating families in the case of the Quillen
metric.


title:
A phase space approach to supercooled liquids and a universal collapse
  of their viscosity

abstract:
  A broad fundamental understanding of the mechanisms underlying the
phenomenology of supercooled liquids has remained elusive, despite decades of
intense exploration. When supercooled beneath its characteristic melting
temperature, a liquid sees a sharp rise in its viscosity over a narrow
temperature range, eventually becoming frozen on laboratory timescales.
Explaining this immense increase in viscosity is one of the principle goals of
condensed matter physicists. To that end, numerous theoretical frameworks have
been proposed which explain and reproduce the temperature dependence of the
viscosity of supercooled liquids. Each of these frameworks appears only
applicable to specific classes of glassformers and each possess a number of
variable parameters. Here we describe a classical framework for explaining the
dynamical behavior of supercooled liquids based on statistical mechanical
considerations, and possessing only a single variable parameter. This parameter
varies weakly from liquid to liquid. Furthermore, as predicted by this new
classical theory and its earlier quantum counterpart, we find with the aid of a
small dimensionless constant that varies in size from $\sim 0.05-0.12$, a
universal (16 decade) collapse of the viscosity data as a function of
temperature. The collapse appears in all known types of glass forming
supercooled liquids (silicates, metallic alloys, organic systems, chalcogenide,
sugars, and water).


title: Access Control in Linked Data Using WebID

abstract:
  Linked Data technologies become increasingly important in many domains. Key
factors for their breakthrough are security and trust, especially when sensible
or personal data are involved. Classical means for access control lack
granularity when parts of the Linked Data graph must be protected. The WebID,
combining semantic web concepts with methods from certificate based
authentication and authorization, seems promising to fulfill all requirements
concerning security and trust in the semantic web. In the context of the
PerSemID project, we challenged the WebID technology in a practical scenario
coming from the domain of lifelong learning and student mobility. In our use
case of study enrollment, we use WebIDs for authentication and to grant access
to parts of the triple stores of the different stakeholders. Cross domain
triple store interactions are used to exchange data between the involved
parties. Our fully implemented PoC exemplifies an application built on Linked
Data and WebID and allows us to judge the usability and security of WebID
technology in a real world scenario.


title:
Lepton Sector Phases and Their Roles in Flavor and Generalized CP
  Symmetries

abstract:
  We study the effects of considering nontrivial unphysical lepton sector
phases on the group theoretical properties of the flavor and generalized CP
symmetry elements in the case where there are three light, distinct Majorana
neutrino species. We highlight the similarities and differences between the
charged lepton and neutrino sectors and further elucidate the group properties
of the flavor and generalized CP symmetry elements. We show how the inclusion
of these leptonic phases affects the bottom-up constructions of these symmetry
elements and discuss the implications for top-down model building based on
discrete symmetry groups.


title: Attributing Hacks

abstract:
  In this paper we describe an algorithm for estimating the provenance of hacks
on websites. That is, given properties of sites and the temporal occurrence of
attacks, we are able to attribute individual attacks to joint causes and
vulnerabilities, as well as estimating the evolution of these vulnerabilities
over time. Specifically, we use hazard regression with a time-varying additive
hazard function parameterized in a generalized linear form. The activation
coefficients on each feature are continuous-time functions over time. We
formulate the problem of learning these functions as a constrained variational
maximum likelihood estimation problem with total variation penalty and show
that the optimal solution is a 0th order spline (a piecewise constant function)
with a finite number of known knots. This allows the inference problem to be
solved efficiently and at scale by solving a finite dimensional optimization
problem. Extensive experiments on real data sets show that our method
significantly outperforms Cox's proportional hazard model. We also conduct a
case study and verify that the fitted functions are indeed recovering
vulnerable features and real-life events such as the release of code to exploit
these features in hacker blogs.


title: Stealths on $(1+1)$-dimensional dilatonic gravity

abstract:
  We study gravitational stealth configurations emerging on a charged dilatonic
$(1+1)$-D black hole spacetime. We accomplish this by considering the coupling
of a non-minimally scalar field $\phi$ and a self-interacting scalar field
$\Psi$ living in a $(1+1)$-D charged black hole background. In addition, the
self-interacting potential for $\Psi$ is obtained which exhibits transitions
for some specific values of the non-minimal parameter. Atypically, we found
that the solutions for these stealth scalar fields do not have a dependence on
the temporal coordinate.


title: Stochastic Fixed Points and Nonlinear Perron-Frobenius Theorem

abstract:
  We provide conditions for the existence of measurable solutions to the
equation $\xi(T\omega)=f(\omega,\xi(\omega))$, where $T:\Omega
\rightarrow\Omega$ is an automorphism of the probability space $\Omega$ and
$f(\omega,\cdot)$ is a strictly non-expansive mapping. We use results of this
kind to establish a stochastic nonlinear analogue of the Perron-Frobenius
theorem on eigenvalues and eigenvectors of a positive matrix. We consider a
random mapping $D(\omega)$ of a random closed cone $K(\omega)$ in a
finite-dimensional linear space into the cone $K(T\omega)$. Under assumptions
of monotonicity and homogeneity of $D(\omega)$, we prove the existence of
scalar and vector measurable functions $\alpha(\omega)>0$ and $x(\omega)\in
K(\omega)$ satisfying the equation $\alpha(\omega)x(T\omega)=D(\omega
)x(\omega)$ almost surely.


title:
Green's formula and a Dirichlet-to-Neumann operator for fractional-order
  pseudodifferential operators

abstract:
  The paper treats boundary value problems for the fractional Laplacian
$(-\Delta )^a$, $a>0$, and more generally for classical pseudodifferential
operators ($\psi $do's) $P$ of order $2a$ with even symbol, applied to
functions on a smooth subset $\Omega $ of ${\Bbb R}^n$. There are several
meaningful local boundary conditions, such as the Dirichlet and Neumann
conditions $\gamma_k^{a-1}u=\varphi $, $k=0,1$, where
$\gamma_k^{a-1}u=c_k\partial_n^k(u/d^{a-1})|_{\partial\Omega }$,
$d(x)=\operatorname{dist}(x,\partial\Omega )$. We show a new Green's formula
$$(Pu,v)_\Omega -(u,P^*v)_\Omega
=(s_0\gamma_1^{a-1}u+B\gamma_0^{a-1}u,\gamma_0^{a-1}v)_{\partial\Omega
}-(s_0\gamma_0^{a-1}u,\gamma_1^{a-1}v)_{\partial\Omega },$$ where $B$ is a
first-order $\psi $do on $\partial\Omega $ depending on the first two terms in
the symbol of $P$.
  Moreover, we show in the elliptic case how the Poisson-like solution operator
$K_D$ for the nonhomogeneous Dirichlet problem is constructed from $P^+$ in the
factorization $P\sim P^-P^+$ obtained in earlier work. The Dirichlet-to-Neumann
operator $S_{DN}=\gamma_1^{a-1}K_D$ is derived from this as a first-order $\psi
$do on $\partial\Omega $, with an explicit formula for the symbol. This leads
to a characterization of those operators $P$ for which the Neumann problem is
Fredholm solvable.


title: Markov-Dyck shifts, neutral periodic points and topological conjugacy

abstract:
  We study the neutral periodic points of the Markov-Dyck shifts of finite
strongly connected directed graphs. Under certain hypothesis on the structure
of the graphs we show, that the topological conjugacy of their Markov-Dyck
shifts implies the isomorphism of the graphs.


title:
Dynamical signatures of structural connectivity damage to a model of the
  brain posed at criticality

abstract:
  Synchronization of brain activity fluctuations is believed to represent
communication between spatially distant neural processes. These inter-areal
functional interactions develop in the background of a complex network of
axonal connections linking cortical and sub-cortical neurons, termed the human
"structural connectome". Theoretical considerations and experimental evidence
support the view that the human brain can be modeled as a system operating at a
critical point between ordered (sub-critical) and disordered (super-critical)
phases. Here, we explore the hypothesis that pathologies resulting from brain
injury of different etiology are related to the model of a critical brain. For
this purpose, we investigate how damage to the integrity of the structural
connectome impacts on the signatures of critical dynamics. Adopting a hybrid
modeling approach combining an empirical weighted network of human structural
connections with a conceptual model of critical dynamics, we show that lesions
located at highly transited connections progressively displace the model
towards the sub-critical regime. The topological properties of the nodes and
links are of less importance when considered independently of their weight in
the network. We observe that damage to midline hubs such as the middle and
posterior cingulate cortex is most crucial for the disruption of criticality in
the model. However, a similar effect can be achieved by targeting less
transited nodes and links whose connection weights add up to an equivalent
amount. This implies that brain pathology does not necessarily arise due to
insult targeted at well-connected areas and that inter- subject variability
could obscure lesions located at non-hub regions. Finally, we discuss the
predictions of our model in the context of clinical studies of traumatic brain
injury and neurodegenerative disorders.


title: Singularities of the Hilbert scheme of non-reduced curves

abstract:
  In this article, we study the Hilbert scheme of generically non-reduced
curves in $\mathbb{P}^3$. We prove the existence of generically non-reduced
curves in $\mathbb{P}^3$ for which there exist infinitesimal deformations of
the curve that do not induce deformations of the associated reduced scheme. We
show that such infinitesimal deformations contribute to the non-reducedness of
the corresponding Hilbert scheme. We introduce the notion of extension of
curves and prove that such infinitesimal deformations (such that the associated
reduced scheme does not deform) are inherited by the extended curve. Finally,
we give examples of extension of curves.


title: Node Embedding via Word Embedding for Network Community Discovery

abstract:
  Neural node embeddings have recently emerged as a powerful representation for
supervised learning tasks involving graph-structured data. We leverage this
recent advance to develop a novel algorithm for unsupervised community
discovery in graphs. Through extensive experimental studies on simulated and
real-world data, we demonstrate that the proposed approach consistently
improves over the current state-of-the-art. Specifically, our approach
empirically attains the information-theoretic limits for community recovery
under the benchmark Stochastic Block Models for graph generation and exhibits
better stability and accuracy over both Spectral Clustering and Acyclic Belief
Propagation in the community recovery limits.


title:
A performance comparison of continuous and discontinuous Galerkin
  methods with fast multigrid solvers

abstract:
  This study presents a fair performance comparison of the continuous finite
element method, the symmetric interior penalty discontinuous Galerkin method,
and the hybridized discontinuous Galerkin method. Modern implementations of
high-order methods with state-of-the-art multigrid solvers for the Poisson
equation are considered, including fast matrix-free implementations with sum
factorization on quadrilateral and hexahedral elements. For the hybridized
discontinuous Galerkin method, a multigrid approach that combines a grid
transfer from the trace space to the space of linear finite elements with
algebraic multigrid on further levels is developed. Despite similar solver
complexity of the matrix-based HDG solver and matrix-free geometric multigrid
schemes with continuous and discontinuous Galerkin finite elements, the latter
offer up to order of magnitude faster time to solution, even after including
the superconvergence effects. This difference is because of vastly better
performance of matrix-free operator evaluation as compared to sparse
matrix-vector products. A roofline performance model confirms the advantage of
the matrix-free implementation.


title: Period Changes and Evolution in Pulsating Variable Stars

abstract:
  We review ways in which observations of the changing periods of pulsating
variable stars can be used to detect and directly measure their evolution. We
briefly describe the two main techniques of analysis -- (O-C) analysis and
wavelet analysis -- and results for pulsating variable star types which are
reasonably periodic: type I and II Cepheids, RR Lyrae stars, beta Cephei stars,
and Mira stars. We comment briefly on delta Scuti stars and pulsating white
dwarfs. For some of these variable star types, observations agree approximately
with the predictions of evolutionary models, but there still exist significant
areas of disagreement that challenge future models of stellar evolution. There
may be a need, for instance, to include processes such as rotation, mass loss,
and magnetic fields. There may also be non-evolutionary processes which are
contributing to the period changes.


title:
Understanding and reducing deleterious defects in metastable alloy
  GaAsBi

abstract:
  Technological applications of novel metastable materials are frequently
inhibited by abundant defects residing in these materials. Using
first-principles methods we investigate the point defect thermodynamics and
phase segregation in the technologically-important metastable alloy GaAsBi. Our
calculations predict defect energy levels in good agreement with abundant
previous experiments and clarify the defect structures giving rise to these
levels. We find that vacancies in some charge states become metastable or
unstable with respect to antisite formation, and this instability is a general
characteristic of zincblende semiconductors with small ionicity. The dominant
point defects degrading electronical and optical performances are predicted to
be As$_G$$_a$, Bi$_G$$_a$, Bi$_G$$_a$+Bi$_A$$_s$, As$_G$$_a$+Bi$_A$$_s$,
V$_G$$_a$ and V$_G$$_a$+Bi$_A$$_s$, of which the first-four and second-two
defects are minority-electron and minority-hole traps, respectively. V$_G$$_a$
is also found to play a critical role in controlling the metastable Bi
supersaturation through mediating Bi diffusion and clustering. To reduce the
influences of these deleterious defects, we suggest shifting the growth away
from As-rich condition and/or using hydrogen passivation to reduce the
minority-carrier traps. We expect this work to aid in the applications of
GaAsBi to novel electronic and optoelectronic devices, and shine a light on
controlling the deleterious defects in other metastable materials.


title: The mechanocaloric potential of spin crossover compounds

abstract:
  We present a first evaluation of the potential for spin crossover (SCO)
compounds to be considered as a new class of giant mechanocaloric effect
material. From literature data on the variation of the spin crossover
temperature with pressure, we estimate the maximum available adiabatic
temperature change for several compounds and the relatively low pressures that
may be required to observe these effects.


title: On the Diffusion Geometry of Graph Laplacians and Applications

abstract:
  We study directed, weighted graphs $G=(V,E)$ and consider the (not
necessarily symmetric) averaging operator $$ (\mathcal{L}u)(i) = -\sum_{j
\sim_{} i}{p_{ij} (u(j) - u(i))},$$ where $p_{ij}$ are normalized edge weights.
Given a vertex $i \in V$, we define the diffusion distance to a set $B \subset
V$ as the smallest number of steps $d_{B}(i) \in \mathbb{N}$ required for half
of all random walks started in $i$ and moving randomly with respect to the
weights $p_{ij}$ to visit $B$ within $d_{B}(i)$ steps. Our main result is that
the eigenfunctions interact nicely with this notion of distance. In particular,
if $u$ satisfies $\mathcal{L}u = \lambda u$ on $V$ and $$ B = \left\{ i \in V:
- \varepsilon \leq u(i) \leq \varepsilon \right\} \neq \emptyset,$$ then, for
all $i \in V$, $$ d_{B}(i) \log{\left( \frac{1}{|1-\lambda|} \right) } \geq
\log{\left( \frac{ |u(i)| }{\|u\|_{L^{\infty}}} \right)} -
\log{\left(\frac{1}{2} + \varepsilon\right)}.$$ $d_B(i)$ is a remarkably good
approximation of $|u|$ in the sense of having very high correlation. The result
implies that the classical one-dimensional spectral embedding preserves
particular aspects of geometry in the presence of clustered data. We also give
a continuous variant of the result which has a connection to the hot spots
conjecture.


title:
Shape universality classes in the random sequential addition of
  non-spherical particles

abstract:
  Random sequential addition (RSA) models are used in a large variety of
contexts to model particle aggregation and jamming. A key feature of these
models is the algebraic time dependence of the asymptotic jamming coverage as
$t\to\infty$. For the RSA of monodisperse non-spherical particles the scaling
is generally believed to be $~t^{-\nu}$, where $\nu=1/d_{\rm f}$ for a particle
with $d_{\rm f}$ degrees of freedom. While the $d_{\rm f}=1$ result of spheres
(Renyi's classical car parking problem) can be derived analytically, evidence
for the $1/d_{\rm f}$ scaling for arbitrary particle shapes has so far only
been provided from empirical studies on a case-by-case basis. Here, we show
that the RSA of arbitrary non-spherical particles, whose centres of mass are
constrained to fall on a line, can be solved analytically for moderate aspect
ratios. The asymptotic jamming coverage is determined by a Laplace-type
integral, whose asymptotics is fully specified by the contact distance between
two particles of given orientations. The analysis of the contact function $r$
shows that the scaling exponent depends on particle shape and falls into two
universality classes for generic shapes with $\tilde{d}$ orientational degrees
of freedom: (i) $\nu=1/(1+\tilde{d}/2)$ when $r$ is a smooth function of the
orientations as for smooth convex shapes, e.g., ellipsoids; (ii)
$\nu=1/(1+\tilde{d})$ when $r$ contains singularities due to flat sides as for,
e.g., spherocylinders and polyhedra. The exact solution explains in particular
why many empirically observed scalings in $2d$ and $3d$ fall in between these
two limiting values.


title:
Enhancing quantum state transfer efficiency in binary-tree spin networks
  by partially collapsing measurements

abstract:
  In this work, quantum state transfer (QST) over binary-tree spin networks is
studied by using advantages of partially collapsing measurements. To this aim,
we perform initially a weak measurement (WM) on central qubit of the
binary-tree network, which encoding the state of concern and after time
evolution of the whole system, a quantum measurement reversal (QMR) on the
destined qubit is performed. By taking the optimal value of the QMR, it is
shown that the QST can be improved considerably by controlling the WM strength
and by choosing it close enough to 1, near-perfect QST can be achieved. We also
show that how entanglement distribution quality over the binary-tree spin
network can be obviously improved by using this approach.


title: A unified treatment of tidal disruption by Schwarzschild black holes

abstract:
  Stars on orbits with pericenters sufficiently close to the supermassive black
hole at the center of their host galaxy can be ripped apart by tidal stresses.
Some of the resulting stellar debris becomes more tightly bound to the hole and
can potentially produce an observable flare called a tidal-disruption event
(TDE). We provide a self-consistent, unified treatment of TDEs by non-spinning
(Schwarzschild) black holes, investigating several effects of general
relativity including changes to the boundary in phase space that defines the
loss-cone orbits on which stars are tidally disrupted or captured. TDE rates
decrease rapidly at large black-hole masses due to direct stellar capture, but
this effect is slightly countered by the widening of the loss cone due to the
stronger tidal fields in general relativity. We provide a new mapping procedure
that translates between Newtonian gravity and general relativity, allowing us
to better compare predictions in both gravitational theories. Partial tidal
disruptions in relativity will strip more material from the star and produce
more tightly bound debris than in Newtonian gravity for a stellar orbit with
the same angular momentum. However, for deep encounters leading to full
disruption in both theories, the stronger tidal forces in relativity imply that
the star is disrupted further from the black hole and that the debris is
therefore less tightly bound, leading to a smaller peak fallback accretion
rate. We also examine the capture of tidal debris by the horizon and the
relativistic pericenter precession of tidal debris, finding that black holes of
$10^6$ solar masses and above generate tidal debris precessing by $10^\circ$ or
more per orbit.


title:
Anisotopic inflation with a non-abelian gauge field in Gauss-Bonnet
  gravity

abstract:
  In presence of Gauss-Bonnet corrections, we study anisotropic inflation aided
by a massless $SU(2)$ gauge field where both the gauge field and the
Gauss-Bonnet term are non-minimally coupled to the inflaton. In this scenario,
under slow-roll approximations, the anisotropic inflation is realized as an
attractor solution with quadratic forms of inflaton potential and Gauss-Bonnet
coupling function. We show that the degree of anisotropy is proportional to the
additive combination of two slow-roll parameters of the theory. The anisotropy
may become either positive or negative similar to the non-Gauss-Bonnet
framework, a feature of the model for anisotropic inflation supported by a
non-abelian gauge field but the effect of Gauss-Bonnet term further enhances or
suppresses the generated anisotropy.


title: Some phenomena in tautological rings of manifolds

abstract:
  We prove several basic ring-theoretic results about tautological rings of
manifolds W, that is, the rings of generalised Miller--Morita--Mumford classes
for fibre bundles with fibre W. Firstly we provide conditions on the rational
cohomology of W which ensure that its tautological ring is finitely-generated,
and we show that these conditions cannot be completely relaxed by giving an
example of a tautological ring which fails to be finitely-generated in quite a
strong sense. Secondly, we provide conditions on torus actions on W which
ensure that the rank of the torus gives a lower bound for the Krull dimension
of the tautological ring of W. Lastly, we give extensive computations in the
tautological rings of CP^2 and S^2 x S^2.


title: Finite Propagation Speed of Waves in Anisotropic Viscoelastic Media

abstract:
  Finite propagation speed properties in mathematical elastic and viscoelastic
models are fundamental in many applications where the data exhibits propagating
fronts. We note particularly that this property is observed in biomechanical
imaging of tissue, in particular in the supersonic imaging experiment, and also
in geophysics and ocean acoustics. With these applications in mind, noting that
there are many other applications as well, we present finite propagation speed
results for very general integro-differential, anisotropic, viscoelastic linear
models, which are not necessarily of convolution type. We start with work
density, define work density decomposition and we achieve our results utilizing
energy arguments. One of the advantages of our presented method, instead of
using plane wave arguments, is that there is no need to make the homogeneous
medium assumption to obtain the finite propagation speed results.


title:
Transduction between electrical energy and the heat in a carbon nanotube
  using a voltage-controlled doping

abstract:
  High electric conductivity ~100 MegaSiemens/m and Seebeck coefficient >200
mkV/K of carbon nanotubes (CNT) make them attractive for a variety of
applications. Unfortunately, a high thermal conductivity ~ 3000 W/(m*K) due to
the phonon transport limits their capability for transforming energy between
the heat and electricity. Here we show that increasing the charge carrier
concentrations not only leads to an increase of both electric conductivity and
Seebeck coeffcient, but also causes a substantial suppression of the thermal
conductivity due to intensifying the phonon-electron collisions. A strong
transduction effect corresponding to an effective electron temperature change
~115 K was observed in a CNT device, where the local gate electrodes have
controlled the charge doping in the opposite ends. Transduction between the
heat and the energy of the electron subsystem corresponds to an impressive
figure of merit cold ZT ~ 6 and the transduced power density P ~ 80kW/cm2.


title:
Geophysical flows under location uncertainty, Part II: Quasi-geostrophy
  and efficient ensemble spreading

abstract:
  Models under location uncertainty are derived assuming that a component of
the velocity is uncorrelated in time. The material derivative is accordingly
modified to include an advection correction, inhomogeneous and anisotropic
diffusion terms and a multiplicative noise contribution. In this paper,
simplified geophysical dynamics are derived from a Boussinesq model under
location uncertainty. Invoking usual scaling approximations and a moderate
influence of the subgrid terms, stochastic formulations are obtained for the
stratified Quasi-Geostrophy (QG) and the Surface Quasi-Geostrophy (SQG) models.
Based on numerical simulations, benefits of the proposed stochastic formalism
are demonstrated. A single realization of models under location uncertainty can
restore small-scale structures. An ensemble of realizations further helps to
assess model error prediction and outperforms perturbed deterministic models by
one order of magnitude. Such a high uncertainty quantification skill is of
primary interests for assimilation ensemble methods. MATLAB code examples are
available online.


title:
On the product of a singular Wishart matrix and a singular Gaussian
  vector in high dimension

abstract:
  In this paper we consider the product of a singular Wishart random matrix and
a singular normal random vector. A very useful stochastic representation is
derived for this product, using which the characteristic function of the
product and its asymptotic distribution under the double asymptotic regime are
established. The application of obtained stochastic representation speeds up
the simulation studies where the product of a singular Wishart random matrix
and a singular normal random vector is present. We further document a good
performance of the derived asymptotic distribution within a numerical
illustration. Finally, several important properties of the singular Wishart
distribution are provided.


title: Pseudorandomness of the Ostrowski sum-of-digits function

abstract:
  For an irrational $\alpha\in(0,1)$, we investigate the Ostrowski
sum-of-digits function $\sigma_\alpha$. For $\alpha$ having bounded partial
quotients and $\vartheta\in\mathbb R\setminus\mathbb Z$, we prove that the
function $g:n\mapsto \mathrm e(\vartheta \sigma_\alpha(n))$, where $\mathrm
e(x)=\mathrm e^{2\pi i x}$, is pseudorandom in the following sense: for all
$r\in\mathbb N$ the limit \[\gamma_r= \lim_{N\rightarrow\infty}\frac
1N\sum_{0\leq n<N}g(n+r)\overline{g(n)} \] exists and we have
\[\lim_{R\rightarrow\infty}\frac 1R\sum_{0\leq r<R}\bigl\lvert
\gamma_r\bigr\rvert^2=0.\]


title: Exploring Vickrey-Clarke-Groves Mechanism for Electricity Markets

abstract:
  Control reserves are power generation or consumption entities that ensure
balance of supply and demand of electricity in real-time. In many countries,
they are operated through a market mechanism in which entities provide bids.
The system operator determines the accepted bids based on an optimization
algorithm. We develop the Vickrey-Clarke-Groves (VCG) mechanism for these
electricity markets. We show that all advantages of the VCG mechanism including
incentive compatibility of the equilibria and efficiency of the outcome can be
guaranteed in these markets. Furthermore, we derive conditions to ensure
collusion and shill bidding are not profitable. Our results are verified with
numerical examples.


title: Large images of reducible galois representations

abstract:
  Given a reducible Galois representation $\overline{\rho}: G_{\mathbb{Q}}
\rightarrow GL_2( \mathbb{F}_q)$ we show there exists an irreducible
deformation $\rho : G_{\mathbb{Q}} \rightarrow GL_2 (\mathbb{W} [[T_1, T_2,..,
T_r,....,]])$ of $\overline{\rho}$ ramified at infinitely many primes, where
$\mathbb{W}$ denotes the ring of Witt vectors of $\mathbb{F}_q$. This is a
modification of Ramakrishna's result for the irreducible case.


title:
Channel Estimation for Hybrid Architecture Based Wideband Millimeter
  Wave Systems

abstract:
  Hybrid analog and digital precoding allows millimeter wave (mmWave) systems
to achieve both array and multiplexing gain. The design of the hybrid precoders
and combiners, though, is usually based on knowledge of the channel. Prior work
on mmWave channel estimation with hybrid architectures focused on narrowband
channels. Since mmWave systems will be wideband with frequency selectivity, it
is vital to develop channel estimation solutions for hybrid architectures based
wideband mmWave systems. In this paper, we develop a sparse formulation and
compressed sensing based solutions for the wideband mmWave channel estimation
problem for hybrid architectures. First, we leverage the sparse structure of
the frequency selective mmWave channels and formulate the channel estimation
problem as a sparse recovery in both time and frequency domains. Then, we
propose explicit channel estimation techniques for purely time or frequency
domains and for combined time/frequency domains. Our solutions are suitable for
both SC-FDE and OFDM systems. Simulation results show that the proposed
solutions achieve good channel estimation quality, while requiring small
training overhead. Leveraging the hybrid architecture at the transceivers gives
further improvement in estimation error performance and achievable rates.


title:
Geophysical flows under location uncertainty, Part III: SQG and frontal
  dynamics under strong turbulence conditions

abstract:
  Models under location uncertainty are derived assuming that a component of
the velocity is uncorrelated in time. The material derivative is accordingly
modified to include an advection correction, inhomogeneous and anisotropic
diffusion terms and a multiplicative noise contribution. This change can be
consitently applied to all fluid dynamics evolution laws. This paper continues
to explore benefits of this framework and consequences of specific scaling
assumptions. Starting from a Boussinesq model under location uncertainty, a
model is developed to describe a mesoscale flow subject to a strong underlying
submesoscale activity. As obtained, the geostrophic balance is modified and the
Quasi-Geostrophic (QG) assumptions remarkably lead to a zero Potential
Vorticity (PV). The ensuing Surface Quasi-Geostrophic (SQG) model provides a
simple diagnosis of warm frontolysis and cold frontogenesis.


title: What is dimension?

abstract:
  This chapter explores the notion of "dimension" of a set. Various power laws
by which an Euclidean space can be characterized are used to define dimensions,
which then explore different aspects of the set. Also discussed are the
generalization to multifractals, and discrete and continuous scale invariance
with the emergence of complex dimensions. The idea of renormalization group
flow equations can be introduced in this framework, to show how the power laws
determined by dimensional analysis (engineering dimensions) get modified by
extra anomalous dimensions. As an example of the RG flow equation, the scaling
of conductance by disorder in the context of localization is used. A few
technicalities, including the connection between entropy and fractal dimension,
can be found in the appendices.


title:
Three-body interacting dipolar bosons and the fate of lattice
  supersolidity

abstract:
  We investigate a system of dipolar bosons in an optical lattice with local
two and three-body interactions. Using the mean-field theory approach, we
obtain the ground state phase diagram of the extended Bose-Hubbard (EBH) model
with both repulsive and attractive three-body interac- tions. We show that the
additional three-body on-site interaction has strong effects on the phase
diagram especially on the supersolid phase. Positive values of the three-body
interaction lead to the enhancement of the gapped phases at densities larger
than unity by reducing the supersolid region. However, a small attractive
three-body interaction enhances the supersolid phase.


title:
Collective Near-Field Thermal Emission from Polaritonic Nanoparticle
  Arrays

abstract:
  The spectral characteristics of near-field thermal emission from nanoparticle
arrays are explained by comparison to the dispersions for propagating modes.
Using the coupled dipole model, we analytically calculate the spectral emission
from single particles, chains, planes, and 3D arrays of SiO2 and SiC. We show
that the differences in their spectra are due to the existence or absence of
propagating surface phonon polariton modes and that the emission is dominated
by these modes when they are present. This work paves the way for understanding
and control of near-field radiation in nanofluids, nanoparticle beds, and
certain metamaterials.


title:
Solution to the first Cousin problem for vector-valued quasianalytic
  functions

abstract:
  We study spaces of vector-valued quasianalytic functions and solve the first
Cousin problem in these spaces.


title: Cluster algebraic interpretation of infinite friezes

abstract:
  Originally studied by Conway and Coxeter, friezes appeared in various
recreational mathematics publications in the 1970s. More recently, in 2015,
Baur, Parsons, and Tschabold constructed periodic infinite friezes and related
them to matching numbers in the once-punctured disk and annulus. In this paper,
we study such infinite friezes with an eye towards cluster algebras of type D
and affine A, respectively. By examining infinite friezes with Laurent
polynomial entries, we discover new symmetries and formulas relating the
entries of this frieze to one another. Lastly, we also present a correspondence
between Broline, Crowe and Isaacs's classical matching tuples and combinatorial
interpretations of elements of cluster algebras from surfaces.


title:
Applying Bag of System Calls for Anomalous Behavior Detection of
  Applications in Linux Containers

abstract:
  In this paper, we present the results of using bags of system calls for
learning the behavior of Linux containers for use in anomaly-detection based
intrusion detection system. By using system calls of the containers monitored
from the host kernel for anomaly detection, the system does not require any
prior knowledge of the container nature, neither does it require altering the
container or the host kernel.


title:
Throughput Analysis of Decentralized Coded Content Caching in Cellular
  Networks

abstract:
  Decentralized coded content caching for next generation cellular networks is
studied. The contents are linearly combined and cached in under-utilized caches
of User Terminals (UTs) and its throughput capacity is compared with
decentralized uncoded content caching. In both scenarios, we consider multihop
Device-to-Device (D2D) communications and the use of femtocaches in the
network. It is shown that decentralized coded content caching can increase the
network throughput capacity compared to decentralized uncoded caching by
reducing the number of hops needed to deliver the desired content. Further, the
throughput capacity for Zipfian content request distribution is computed and it
is shown that the decentralized coded content cache placement can increase the
throughput capacity of cellular networks by a factor of $(\log(n))^2$ where $n$
is the number of nodes served by a femtocache.


title:
Remote monitoring of weak aftershock activity with waveform cross
  correlation: the case of the DPRK September 9, 2016 underground test

abstract:
  The method of waveform cross correlation (WCC) allows remote monitoring of
weak seismic activity induced by underground tests. This type of monitoring is
considered as a principal task of on-site inspection under the Comprehensive
nuclear-test-ban treaty. On September 11, 2016, a seismic event with body wave
magnitude 2.1 was found in automatic processing near the epicenter of the
underground explosion conducted by the DPRK on September 9, 2016. This event
occurred approximately two days after the test. Using the WCC method, two array
stations of the International Monitoring System (IMS), USRK and KSRS, detected
Pn-wave arrivals, which were associated with a unique event. Standard automatic
processing at the International Data Centre (IDC) did not create an event
hypothesis, but in the following interactive processing based on WCC
detections, an IDC analyst was able to create a two-station event . Location
and other characteristics of this small seismic source indicate that it is
likely an aftershock of the preceding explosion. Building on the success of
automatic detection and phase association, we carried out an extended analysis,
which included later phases and closest non-IMS stations. The final cross
correlation solution uses four stations, including MDJ (China) and SEHB
(Republic of Korea), with the epicenter approximately 2 km to north-west from
the epicenter of the Sept. 9 test. We also located the aftershock epicenter by
standard IDC program LocSAT using the arrival times obtained by cross
correlation. The distance between the DPRK and LocSAT aftershock epicenters is
25.5 km, i.e. by an order of magnitude larger than that obtained by the WCC
relative location method.


title: Intrusion Detection System for Applications using Linux Containers

abstract:
  Linux containers are gaining increasing traction in both individual and
industrial use, and as these containers get integrated into mission-critical
systems, real-time detection of malicious cyber attacks becomes a critical
operational requirement. This paper introduces a real-time host-based intrusion
detection system that can be used to passively detect malfeasance against
applications within Linux containers running in a standalone or in a cloud
multi-tenancy environment. The demonstrated intrusion detection system uses
bags of system calls monitored from the host kernel for learning the behavior
of an application running within a Linux container and determining anomalous
container behavior. Performance of the approach using a database application
was measured and results are discussed.


title:
When silver glitters more than gold: Bootstrapping an Italian
  part-of-speech tagger for Twitter

abstract:
  We bootstrap a state-of-the-art part-of-speech tagger to tag Italian Twitter
data, in the context of the Evalita 2016 PoSTWITA shared task. We show that
training the tagger on native Twitter data enriched with little amounts of
specifically selected gold data and additional silver-labelled data scraped
from Facebook, yields better results than using large amounts of manually
annotated data from a mix of genres.


title: Equivariant Derived Categories Associated to a Sum of Two Potentials

abstract:
  Suppose $f,g$ are homogeneous polynomials of degree $d$ defining smooth
hypersurfaces $X_f = V(f)\subset \mathbb{P}^{m-1}$ and $X_g =
V(g)\subset\mathbb{P}^{n-1}$. Then the sum $f(x)+g(y)$ defines a smooth
hypersurface $X=V(f(x)+g(y))\subset\mathbb{P}^{m+n-1}$ with an action of
$\mu_d$ scaling the $g$ variables. Motivated by the work of Orlov, we construct
a semi-orthogonal decomposition of the derived category of coherent sheaves on
$[X/\mu_d]$ provided $d\geq \mathrm{max}\{m,n\}$.


title:
Optimal Surface Segmentation with Convex Priors in Irregularly Sampled
  Space

abstract:
  Optimal surface segmentation is a state-of-the-art method used for
segmentation of multiple globally optimal surfaces in volumetric datasets. The
method is widely used in numerous medical image segmentation applications.
However, nodes in the graph based optimal surface segmentation method typically
encode uniformly distributed orthogonal voxels of the volume. Thus the
segmentation cannot attain an accuracy greater than a single unit voxel, i.e.
the distance between two adjoining nodes in graph space. Segmentation accuracy
higher than a unit voxel is achievable by exploiting partial volume information
in the voxels which shall result in non-equidistant spacing between adjoining
graph nodes. This paper reports a generalized graph based multiple surface
segmentation method with convex priors which can optimally segment the target
surfaces in an irregularly sampled space. The proposed method allows
non-equidistant spacing between the adjoining graph nodes to achieve subvoxel
segmentation accuracy by utilizing the partial volume information in the
voxels. The partial volume information in the voxels is exploited by computing
a displacement field from the original volume data to identify the
subvoxel-accurate centers within each voxel resulting in non-equidistant
spacing between the adjoining graph nodes. The smoothness of each surface
modeled as a convex constraint governs the connectivity and regularity of the
surface. We employ an edge-based graph representation to incorporate the
necessary constraints and the globally optimal solution is obtained by
computing a minimum s-t cut. The proposed method was validated on 10
intravascular multi-frame ultrasound image datasets for subvoxel segmentation
accuracy. In all cases, the approach yielded highly accurate results. Our
approach can be readily extended to higher-dimensional segmentations.


title: The Non-convex Geometry of Low-rank Matrix Optimization

abstract:
  This work considers two popular minimization problems: (i) the minimization
of a general convex function $f(\mathbf{X})$ with the domain being positive
semi-definite matrices; (ii) the minimization of a general convex function
$f(\mathbf{X})$ regularized by the matrix nuclear norm $\|\mathbf{X}\|_*$ with
the domain being general matrices. Despite their optimal statistical
performance in the literature, these two optimization problems have a high
computational complexity even when solved using tailored fast convex solvers.
To develop faster and more scalable algorithms, we follow the proposal of Burer
and Monteiro to factor the low-rank variable $\mathbf{X} =
\mathbf{U}\mathbf{U}^\top $ (for semi-definite matrices) or
$\mathbf{X}=\mathbf{U}\mathbf{V}^\top $ (for general matrices) and also replace
the nuclear norm $\|\mathbf{X}\|_*$ with
$(\|\mathbf{U}\|_F^2+\|\mathbf{V}\|_F^2)/2$. In spite of the non-convexity of
the resulting factored formulations, we prove that each critical point either
corresponds to the global optimum of the original convex problems or is a
strict saddle where the Hessian matrix has a strictly negative eigenvalue. Such
a nice geometric structure of the factored formulations allows many local
search algorithms to find a global optimizer even with random initializations.


title:
Convection Destroys the Core/Mantle Structure in Hybrid C/O/Ne White
  Dwarfs

abstract:
  A hybrid C/O/Ne white dwarf (WD) -- an unburned C/O core surrounded by an
O/Ne/Na mantle -- can be formed if the carbon flame is quenched in a super-AGB
(SAGB) star or white dwarf merger remnant. We show that this segregated hybrid
structure becomes unstable to rapid mixing within 2,000 years of the onset of
WD cooling. Carbon burning includes a weak reaction that removes electrons,
resulting in a lower electron-to-baryon ratio ($Y_{\rm e}$) in the regions
processed by carbon burning compared to the unburned C/O core, making the O/Ne
mantle denser than the C/O core as the WD cools. This is unstable to efficient
mixing. We use the results of $\texttt{MESA}$ models with different size C/O
cores to quantify the rate at which the cores mix with the mantle as they cool.
In all cases, we find that the WDs undergo significant core/mantle mixing on
timescales shorter than the time available to grow the WD to the Chandrasekhar
mass ($M_{\rm Ch}$) by accretion. As a result, hybrid WDs that reach $M_{\rm
Ch}$ due to later accretion will have lower central carbon fractions than
assumed thus far. We briefly discuss the implications of these results for the
possibility of Type Ia supernovae from hybrid WDs.


title: A search for neutrinos from fast radio bursts with IceCube

abstract:
  We present a search for neutrinos in coincidence in time and direction with
four fast radio bursts (FRBs) detected by the Parkes and Green Bank radio
telescopes during the first year of operation of the complete IceCube Neutrino
Observatory (May 2011 through May 2012). The neutrino sample consists of
138,322 muon neutrino candidate events, which are dominated by atmospheric
neutrinos and muons but also contain an astrophysical neutrino component.
Considering only neutrinos detected on the same day as each FRB, zero IceCube
events were found to be compatible with the FRB directions within the estimated
99\% error radius of the neutrino directions. Based on the non-detection, we
present the first upper limits on the neutrino fluence from fast radio bursts.


title:
Prediction Accuracy Measures for a Nonlinear Model and for
  Right-Censored Time-to-Event Data

abstract:
  This paper studies prediction summary measures for a prediction function
under a general setting in which the model is allowed to be misspecified and
the prediction function is not required to be the conditional mean response. We
show that the R2 measure based on a variance decomposition is insufficient to
summarize the predictive power of a nonlinear prediction function. By deriving
a prediction error decompo- sition, we introduce an additional measure, L2, to
augment the R2 measure. When used together, the two measures provide a complete
summary of the predictive power of a prediction function. Furthermore, we
extend these measures to right-censored time-to-event data by establishing
right-censored data analogs of the variance and prediction error
decompositions. We illustrate the usefulness of the proposed mea- sures with
simulations and real data examples. Supplementary materials for this article
are available online.


title: Finite-dimensional collisionless kinetic theory

abstract:
  A collisionless kinetic plasma model may often be cast as an
infinite-dimensional noncanonical Hamiltonian system. I show that, when this is
the case, the model can be discretized in space and particles while preserving
its Hamiltonian structure, thereby producing a finite-dimensional Hamiltonian
system that approximates the original kinetic model. I apply the general theory
to two example systems: the relativistic Vlasov-Maxwell system with spin, and a
gyrokinetic Vlasov-Maxwell system.


title: Toward Smart Moving Target Defense for Linux Container Resiliency

abstract:
  This paper presents ESCAPE, an informed moving target defense mechanism for
cloud containers. ESCAPE models the interaction between attackers and their
target containers as a "predator searching for a prey" search game. Live
migration of Linux-containers (prey) is used to avoid attacks (predator) and
failures. The entire process is guided by a novel host-based
behavior-monitoring system that seamlessly monitors containers for indications
of intrusions and attacks. To evaluate ESCAPE effectiveness, we simulated the
attack avoidance process based on a mathematical model mimicking the
prey-vs-predator search game. Simulation results show high container survival
probabilities with minimal added overhead.


title:
First Direct-Detection Constraints on eV-Scale Hidden-Photon Dark Matter
  with DAMIC at SNOLAB

abstract:
  We present direct detection constraints on the absorption of hidden-photon
dark matter with particle masses in the range 1.2-30 eV$c^{-2}$ with the DAMIC
experiment at SNOLAB. Under the assumption that the local dark matter is
entirely constituted of hidden photons, the sensitivity to the kinetic mixing
parameter $\kappa$ is competitive with constraints from solar emission,
reaching a minimum value of 2.2$\times$$10^{-14}$ at 17 eV$c^{-2}$. These
results are the most stringent direct detection constraints on hidden-photon
dark matter in the galactic halo with masses 3-12 eV$c^{-2}$ and the first
demonstration of direct experimental sensitivity to ionization signals $<$12 eV
from dark matter interactions.


title: Online Abstractions for Interconnected Multi-Agent Control Systems

abstract:
  In this report, we aim at the development of an online abstraction framework
for multi-agent systems under coupled constraints. The motion capabilities of
each agent are abstracted through a finite state transition system in order to
capture reachability properties of the coupled multi-agent system over a finite
time horizon in a decentralized manner. In the first part of this work, we
define online abstractions by discretizing an overapproximation of the agents'
reachable sets over the horizon. Then, sufficient conditions relating the
discretization and the agent's dynamics properties are provided, in order to
quantify the transition possibilities of each agent.


title: Incremental Sequence Learning

abstract:
  Deep learning research over the past years has shown that by increasing the
scope or difficulty of the learning problem over time, increasingly complex
learning problems can be addressed. We study incremental learning in the
context of sequence learning, using generative RNNs in the form of multi-layer
recurrent Mixture Density Networks. While the potential of incremental or
curriculum learning to enhance learning is known, indiscriminate application of
the principle does not necessarily lead to improvement, and it is essential
therefore to know which forms of incremental or curriculum learning have a
positive effect. This research contributes to that aim by comparing three
instantiations of incremental or curriculum learning.
  We introduce Incremental Sequence Learning, a simple incremental approach to
sequence learning. Incremental Sequence Learning starts out by using only the
first few steps of each sequence as training data. Each time a performance
criterion has been reached, the length of the parts of the sequences used for
training is increased.
  We introduce and make available a novel sequence learning task and data set:
predicting and classifying MNIST pen stroke sequences. We find that Incremental
Sequence Learning greatly speeds up sequence learning and reaches the best test
performance level of regular sequence learning 20 times faster, reduces the
test error by 74%, and in general performs more robustly; it displays lower
variance and achieves sustained progress after all three comparison methods
have stopped improving. The other instantiations of curriculum learning do not
result in any noticeable improvement. A trained sequence prediction model is
also used in transfer learning to the task of sequence classification, where it
is found that transfer learning realizes improved classification performance
compared to methods that learn to classify from scratch.


title:
NP-Hardness of Reed-Solomon Decoding, and the Prouhet-Tarry-Escott
  Problem

abstract:
  Establishing the complexity of {\em Bounded Distance Decoding} for
Reed-Solomon codes is a fundamental open problem in coding theory, explicitly
asked by Guruswami and Vardy (IEEE Trans. Inf. Theory, 2005). The problem is
motivated by the large current gap between the regime when it is NP-hard, and
the regime when it is efficiently solvable (i.e., the Johnson radius).
  We show the first NP-hardness results for asymptotically smaller decoding
radii than the maximum likelihood decoding radius of Guruswami and Vardy.
Specifically, for Reed-Solomon codes of length $N$ and dimension $K=O(N)$, we
show that it is NP-hard to decode more than $ N-K- c\frac{\log N}{\log\log N}$
errors (with $c>0$ an absolute constant). Moreover, we show that the problem is
NP-hard under quasipolynomial-time reductions for an error amount $> N-K-
c\log{N}$ (with $c>0$ an absolute constant).
  These results follow from the NP-hardness of a generalization of the
classical Subset Sum problem to higher moments, called {\em Moments Subset
Sum}, which has been a known open problem, and which may be of independent
interest.
  We further reveal a strong connection with the well-studied
Prouhet-Tarry-Escott problem in Number Theory, which turns out to capture a
main barrier in extending our techniques. We believe the Prouhet-Tarry-Escott
problem deserves further study in the theoretical computer science community.


title:
Constant solutions of Yang-Mills equations and generalized Proca
  equations

abstract:
  In this paper we present some new equations which we call Yang-Mills-Proca
equations (or generalized Proca equations). This system of equations is a
generalization of Proca equation and Yang-Mills equations and it is not gauge
invariant. We present a number of constant solutions of this system of
equations in the case of arbitrary Lie algebra. In details we consider the case
when this Lie algebra is Clifford algebra or Grassmann algebra. We consider
solutions of Yang-Mills equations in the form of perturbation theory series
near the constant solution.


title: Fairness in Reinforcement Learning

abstract:
  We initiate the study of fairness in reinforcement learning, where the
actions of a learning algorithm may affect its environment and future rewards.
Our fairness constraint requires that an algorithm never prefers one action
over another if the long-term (discounted) reward of choosing the latter action
is higher. Our first result is negative: despite the fact that fairness is
consistent with the optimal policy, any learning algorithm satisfying fairness
must take time exponential in the number of states to achieve non-trivial
approximation to the optimal policy. We then provide a provably fair polynomial
time algorithm under an approximate notion of fairness, thus establishing an
exponential gap between exact and approximate fairness


title: Apocalypse Now? Reviving the Doomsday Argument

abstract:
  Whether the fate of our species can be forecast from its past has been the
topic of considerable controversy. One refutation of the so-called Doomsday
Argument is based on the premise that we are more likely to exist in a universe
containing a greater number of observers. Here we present a Bayesian
reformulation of the Doomsday Argument which is immune to this effect. By
marginalising over the spatial configuration of observers, we find that any
preference for a larger total number of observers has no impact on the inferred
local number. Our results remain unchanged when we adopt either the
Self-Indexing Assumption (SIA) or the Self-Sampling Assumption (SSA).
Furthermore the median value of our posterior distribution is found to be in
agreement with the frequentist forecast. Humanity's prognosis for the coming
century is well approximated by a global catastrophic risk of 0.2% per year.