title: On the Douglas-Rachford algorithm

abstract:
  The Douglas-Rachford algorithm is a very popular splitting technique for
finding a zero of the sum of two maximally monotone operators. However, the
behaviour of the algorithm remains mysterious in the general inconsistent case,
i.e., when the sum problem has no zeros. More than a decade ago, however, it
was shown that in the (possibly inconsistent) convex feasibility setting, the
shadow sequence remains bounded and it is weak cluster points solve a best
approximation problem.
  In this paper, we advance the understanding of the inconsistent case
significantly by providing a complete proof of the full weak convergence in the
convex feasibility setting. In fact, a more general sufficient condition for
the weak convergence in the general case is presented. Several examples
illustrate the results.


title: Mathematical Analysis of Ultrafast Ultrasound Imaging

abstract:
  This paper provides a mathematical analysis of ultrafast ultrasound imaging.
This newly emerging modality for biomedical imaging uses plane waves instead of
focused waves in order to achieve very high frame rates. We derive the point
spread function of the system in the Born approximation for wave propagation
and study its properties. We consider dynamic data for blood flow imaging, and
introduce a suitable random model for blood cells. We show that a singular
value decomposition method can successfully remove the clutter signal by using
the different spatial coherence of tissue and blood signals, thereby providing
high-resolution images of blood vessels, even in cases when the clutter and
blood speeds are comparable in magnitude. Several numerical simulations are
presented to illustrate and validate the approach.


title: Tunable phonon cavity coupling in graphene membranes

abstract:
  A major achievement of the past decade has been the realization of
macroscopic quantum systems by exploiting interactions between optical cavities
and mechanical resonators. In these systems, phonons are coherently annihilated
or created in exchange for photons. Similar phenomena have recently been
observed through "phonon cavity" coupling -- energy exchange between modes of a
single system as mediated by intrinsic material nonlinearity. To date, this has
been demonstrated primarily for bulk crystalline, high-quality-factor
(Q>100,000) mechanical systems operated at cryogenic temperatures. Here we
propose graphene as an ideal candidate for the study of such nonlinear
mechanics. The large elastic modulus of this material and capability for
spatial symmetry breaking via electrostatic forces is expected to generate a
wealth of nonlinear phenomena, including tunable inter-modal coupling. We have
fabricated circular graphene membranes and report strong phonon cavity effects
at room temperature, despite the modest Q (~100) of this system. We observe
both amplification into parametric instability ("mechanical lasing") and
cooling of Brownian motion in the fundamental mode through excitation of cavity
sidebands. Furthermore, we characterize quenching of these parametric effects
at large vibrational amplitudes, offering a window on the all-mechanical
analogue of cavity optomechanics, where observation of such effects has proven
elusive.


title: Fix-finite approximation property in F-spaces

abstract:
  In this paper, with the aid of the simplicial approximation property, the
Hopf's construction and Dugundji's homotopy extension Theorem, we first show
that if C is a nonempty compact convex subset of an F-space (E; || ||); then
for every positive real number epsilon and every subset D of E containing C and
every continuous map f from D to C there exists a continuous map g from D to C
which is epsilon-near to f and has only a finite number of fixed points.
Secondly, by using this result and the simplicial approximation property, we
establish that for any positive real number epsilon and every path and simply
connected compact subset D of E containing C and for each continuous n-valued
multifunction F from D to C there exists a continuous n-valued multifunction G
from D to C which is epsilon-near to F and has only a finite number of fixed
points.


title:
Amended results for hard X-ray emission by non-thermal thick target
  recombination in solar flares

abstract:
  Brown & Mallik 2008 and the Brown et al. 2010 corrigendum of it presented
expressions for non-thermal recombination (NTR) in the collisionally thin- and
thick-target regimes, claiming that the process could account for a substantial
part of hard X-ray continuum in solar flares usually attributed entirely to
thermal and non-thermal bremsstrahlung (NTB). However, we have found the
thick-target expression to become unphysical for low cut-offs in the injected
electron energy spectrum. We trace this to an error in the derivation, derive a
corrected version which is real-valued and continuous for all photon energies
and cut-offs, and show that, for thick targets, Brown et al. over-estimated NTR
emission at small photon energies. The regime of small cut-offs and large
spectral indices involve large (reducing) correction factors but in some other
thick-target parameter regimes NTR/NTB can still be of order unity. We comment
on the importance of these results to flare and to microflare modeling and
spectral fitting. An empirical fit to our results shows that the peak NTR
contribution comprises over half the hard X-ray signal if delta > 6 (E_0c/4
keV)^(0.4).


title:
Super-hedging American Options with Semi-static Trading Strategies under
  Model Uncertainty

abstract:
  We consider the super-hedging price of an American option in a discrete-time
market in which stocks are available for dynamic trading and European options
are available for static trading. We show that the super-hedging price $\pi$ is
given by the supremum over the prices of the American option under randomized
models. That is, $\pi=\sup_{(c_i,Q_i)_i}\sum_ic_i\phi^{Q_i}$, where $c_i \in
\mathbb{R}_+$ and the martingale measure $Q^i$ are chosen such that $\sum_i
c_i=1$ and $\sum_i c_iQ_i$ prices the European options correctly, and
$\phi^{Q_i}$ is the price of the American option under the model $Q_i$. Our
result generalizes the example given in ArXiv:1604.02274 that the highest model
based price can be considered as a randomization over models.


title:
On separability of the functional space with the open-point and
  bi-point-open topologies, II

abstract:
  In this paper we continue to study the property of separability of functional
space C(X) with the open-point and bi-point-open topologies.


title: The enigmatic 12/5 fractional quantum Hall effect

abstract:
  We numerically study the fractional quantum Hall effect at filling factors
$\nu=12/5$ and 13/5 (the particle-hole conjugate of 12/5) in high-quality
two-dimensional GaAs heterostructures via exact diagonalization including
finite well width and Landau level mixing. We find that Landau level mixing
suppresses $\nu=13/5$ fractional quantum Hall effect relative to $\nu=12/5$. By
contrast, we find both $\nu=2/5$ and (its particle-hole conjugate) $\nu=3/5$
fractional quantum Hall effects in the lowest Landau level to be robust under
Landau level mixing and finite well-width corrections. Our results provide a
possible explanation for the experimental absence of the 13/5 fractional
quantum Hall state as caused by Landau level mixing effects.


title: FormCalc 9 and Extensions

abstract:
  We present Version 9 of the Feynman-diagram calculator FormCalc and a
flexible new suite of shell scripts and Mathematica packages based on FormCalc,
which can be adapted and used as a template for calculations.


title: Non-linear Fields in Generalized Cosmologies

abstract:
  The perturbative approach to structure formation has recently received a lot
of attention in the literature. In such setups the final predictions for
observables like the power spectrum is often derived under additional
approximations such as a simplified time dependence. Here we provide all-order
perturbative integral solutions for density and velocity fields in generalized
cosmologies, with a direct application to clustering quintessence. We go beyond
the standard results based on extending the EdS-like approximations. As an
illustrative example, we apply our findings to the calculation of the one-loop
power spectrum of density and momentum fields. We find corrections close to
$1\%$ in the mildly non-linear regime of $\Lambda$CDM cosmologies for the
density power spectrum, while in the case of the density-momentum power
spectrum effects can reach up to $1.5\%$ for $k\sim 0.2h/$Mpc.


title: Fugitive stars in active galaxies

abstract:
  We investigate in detail the escape dynamics in an analytical gravitational
model which describes the motion of stars in a quasar galaxy with a disk and a
massive nucleus. We conduct a thorough numerical analysis distinguishing
between regular and chaotic orbits as well as between trapped and escaping
orbits, considering only unbounded motion for several energy levels. In order
to distinguish safely and with certainty between ordered and chaotic motion we
apply the Smaller ALingment Index (SALI) method. It is of particular interest
to locate the escape basins through the openings around the collinear
Lagrangian points $L_1$ and $L_2$ and relate them with the corresponding
spatial distribution of the escape times of the orbits. Our exploration takes
place both in the configuration $(x,y)$ and in the phase $(x,\dot{x})$ space in
order to elucidate the escape process as well as the overall orbital properties
of the galactic system. Our numerical analysis reveals the strong dependence of
the properties of the considered escape basins with the total orbital energy,
with a remarkable presence of fractal basin boundaries along all the escape
regimes. We hope our outcomes to be useful for a further understanding of the
escape mechanism in active galaxy models.


title:
Short-time universal scaling and light-cone dynamics after a quench in
  an isolated quantum system in $d$ spatial dimensions

abstract:
  We investigate the effects of fluctuations on the dynamics of an isolated
quantum system represented by a $\phi^4$ field theory with $O(N)$ symmetry
after a quench in $d>2$ spatial dimensions. A perturbative
renormalization-group approach involving a dimensional expansion in
$\epsilon=4-d$ is employed in order to study the evolution within a prethermal
regime controlled by elastic dephasing. In particular, we focus on a quench
from a disordered initial state to the critical point, which introduces an
effective temporal boundary in the evolution. At this boundary, the relevant
fields acquire an anomalous scaling dimension, while the evolution of both the
order parameter and its correlation and response functions display universal
aging. Since the relevant excitations propagate ballistically, a light cone in
real space emerges. At longer times, the onset of inelastic scattering appears
as secularly growing self-generated dissipation in the effective Keldysh field
theory, with the strength of the dissipative vertices providing an estimate for
the time needed to leave the prethermal regime.


title: On deterministic conditions for subspace clustering under missing data

abstract:
  In this paper we present deterministic analysis of sufficient conditions for
sparse subspace clustering under missing data, when data is assumed to come
from a Union of Subspaces (UoS) model. In this context we consider two cases,
namely Case I when all the points are sampled at the same co-ordinates, and
Case II when points are sampled at different locations. We show that results
for Case I directly follow from several existing results in the literature,
while results for Case II are not as straightforward and we provide a set of
dual conditions under which, perfect clustering holds true. We provide
extensive set of simulation results for clustering as well as completion of
data under missing entries, under the UoS model. Our experimental results
indicate that in contrast to the full data case, accurate clustering does not
imply accurate subspace identification and completion, indicating the natural
order of relative hardness of these problems.


title:
Cosmological consequences and statefinder diagnosis of a non-interacting
  generalized Chaplygin gas in $f(R,T)$ gravity

abstract:
  In this paper, we investigate cosmological consequences of a scenario for
recently reported accelerated expansion of the Universe, in which the
generalized Chaplygin gas (GCG) along with the baryonic matter are responsible
for this observed phenomenon. In the present model, we employ an isotropic and
homogeneous FLRW space time in the framework of $f(R,T)$ theory of gravity. In
$f(R,T)$ gravity, the conservation of energy-momentum tensor (EMT) leads to a
constraint equation which enforces us to use some specific forms of type
$f(R,T)=g(R)+h(T)$. In this work we choose $g(R)=R$. We consider three classes
of Chaplygin gas models which include three different forms of $f(R,T)$
function; those models which employ the standard Chaplygin gas (SCG), models
which use GCG in the high pressure regimes and finally, the third case is
devoted to investigating high density regimes in the presence of GCG.


title:
Untwisting the Pure Spinor Formalism to the RNS and Twistor String in a
  Flat and $AdS_5\times S^5$ Background

abstract:
  The pure spinor formalism for the superstring can be formulated as a twisted
N=2 worldsheet theory with fermionic generators $j_{BRST}$ and composite $b$
ghost. After untwisting the formalism to an N=1 worldsheet theory with
fermionic stress tensor $j_{BRST}+b$, the worldsheet variables combine into N=1
worldsheet superfields $X^m$ and $\Theta^\alpha$ together with a superfield
constraint relating $DX^m$ and $D\Theta^\alpha$. The constraint implies that
the worldsheet superpartner of $\theta^\alpha$ is a bosonic twistor variable,
and different solutions of the constraint give rise to the pure spinor or
extended RNS formalisms, as well as a new twistor-string formalism with
manifest N=1 worldsheet supersymmetry.
  These N=1 worldsheet methods generalize in curved Ramond-Ramond backgrounds,
and a manifestly N=1 worldsheet supersymmetric action is proposed for the
superstring in an $AdS_5\times S^5$ background in terms of the twistor
superfields. This $AdS_5\times S^5$ worldsheet action is a remarkably simple
fermionic coset model with manifest $PSU(2,2|4)$ symmetry and might be useful
for computing $AdS_5\times S^5$ superstring scattering amplitudes.


title: Make Up Your Mind: The Price of Online Queries in Differential Privacy

abstract:
  We consider the problem of answering queries about a sensitive dataset
subject to differential privacy. The queries may be chosen adversarially from a
larger set Q of allowable queries in one of three ways, which we list in order
from easiest to hardest to answer:
  Offline: The queries are chosen all at once and the differentially private
mechanism answers the queries in a single batch.
  Online: The queries are chosen all at once, but the mechanism only receives
the queries in a streaming fashion and must answer each query before seeing the
next query.
  Adaptive: The queries are chosen one at a time and the mechanism must answer
each query before the next query is chosen. In particular, each query may
depend on the answers given to previous queries.
  Many differentially private mechanisms are just as efficient in the adaptive
model as they are in the offline model. Meanwhile, most lower bounds for
differential privacy hold in the offline setting. This suggests that the three
models may be equivalent.
  We prove that these models are all, in fact, distinct. Specifically, we show
that there is a family of statistical queries such that exponentially more
queries from this family can be answered in the offline model than in the
online model. We also exhibit a family of search queries such that
exponentially more queries from this family can be answered in the online model
than in the adaptive model. We also investigate whether such separations might
hold for simple queries like threshold queries over the real line.


title:
Comments on the behaviour of some thermodynamic characteristics of
  single component substance in the region defined by the line of liquid vapor
  equilibrium

abstract:
  It is shown that in general case may be not correct the statements of
[1,2,6-8] that 1) the isochoric heat capacity on the entire thermodynamic
surface, including the metastable region of states and the region defined by
the spinodal, remains positive and finite except for the critical point, and 2)
the isobaric heat capacity becomes negative in the region defined by spinodal.


title:
Large linear magnetoresistance and magnetothermopower in layered
  SrZnSb$_2$

abstract:
  We report the large linear magnetoresistance ($\sim 300\%$ in 9 T field at 2
K) and magnetothermopower in layered SrZnSb$_2$ crystal with
quasi-two-dimensional Sb layers. A crossover from the semiclassical parabolic
field dependent magnetoresistance to linear field dependent magnetoresistance
with increasing magnetic field is observed. The magnetoresistance behavior can
be described very well by combining the semiclassical cyclotron contribution
and the quantum limit magnetoresistance. Magnetic field also enhances the
thermopower. Our results can be well understood by the magnetotransport of
Dirac states in the bulk band structure.


title:
Discovery of Three Pulsating, Mixed-atmosphere, Extremely Low-mass White
  Dwarf Precursors

abstract:
  We report the discovery of pulsations in three mixed-atmosphere, extremely
low-mass white dwarf (ELM WD, M $\leqslant$ 0.3 M$_{\odot}$) precursors.
Following the recent discoveries of pulsations in both ELM and pre-ELM WDs, we
targeted pre-ELM WDs with mixed H/He atmospheres with high-speed photometry. We
find significant optical variability in all three observed targets with periods
in the range 320--590 s, consistent in timescale with theoretical predictions
of $p$-mode pulsations in mixed-atmosphere $\approx$ 0.18 M$_{\odot}$ He-core
pre-ELM WDs. This represents the first empirical evidence that pulsations in
pre-ELM WDs can only occur if a significant amount of He is present in the
atmosphere. Future, more extensive, time-series photometry of the brightest of
the three new pulsators offers an excellent opportunity to constrain the
thickness of the surface H layer, which regulates the cooling timescales for
ELM WDs.


title: Escape dynamics in a binary system of interacting galaxies

abstract:
  The escape dynamics in an analytical gravitational model which describes the
motion of stars in a binary system of interacting dwarf spheroidal galaxies is
investigated in detail. We conduct a numerical analysis distinguishing between
regular and chaotic orbits as well as between trapped and escaping orbits,
considering only unbounded motion for several energy levels. In order to
distinguish safely and with certainty between ordered and chaotic motion, we
apply the Smaller ALingment Index (SALI) method. It is of particular interest
to locate the escape basins through the openings around the collinear
Lagrangian points $L_1$ and $L_2$ and relate them with the corresponding
spatial distribution of the escape times of the orbits. Our exploration takes
place both in the configuration $(x,y)$ and in the phase $(x,\dot{x})$ space in
order to elucidate the escape process as well as the overall orbital properties
of the galactic system. Our numerical analysis reveals the strong dependence of
the properties of the considered escape basins with the total orbital energy,
with a remarkable presence of fractal basin boundaries along all the escape
regimes. It was also observed, that for energy levels close to the critical
escape energy the escape rates of orbits are large, while for much higher
values of energy most of the orbits have low escape periods or they escape
immediately to infinity. We hope our outcomes to be useful for a further
understanding of the escape mechanism in binary galaxy models.


title:
Determining the spin-orbit coupling via spin-polarized spectroscopy of
  magnetic impurities

abstract:
  We study the spin-resolved spectral properties of the impurity states
associated to the presence of magnetic impurities in two-dimensional, as well
as one-dimensional systems with Rashba spin-orbit coupling. We focus on Shiba
bound states in superconducting materials, as well as on impurity states in
metallic systems. Using a combination of a numerical T-matrix approximation and
a direct analytical calculation of the bound state wave function, we compute
the local density of states (LDOS) together with its Fourier transform (FT). We
find that the FT of the spin-polarized LDOS, a quantity accessible via
spin-polarized STM, allows to accurately extract the strength of the spin-orbit
coupling. Also we confirm that the presence of magnetic impurities is strictly
necessary for such measurement, and that non-spin-polarized experiments cannot
have access to the value of the spin-orbit coupling.


title: A Model for Type 2 Coronal Line Forest (CLiF) AGN

abstract:
  We present a model for the classification of Coronal-Line Forest Active
Galactic Nuclei (CLiF AGN). CLiF AGN are of special interest due to their
remarkably large number of emission lines, especially forbidden high ionization
lines (FHILs). Rose et al. (2015a) suggest that their emission is dominated by
reflection from the inner wall of the obscuring region rather than direct
emission from the accretion disk. This makes CLiF AGN laboratories to test
AGN-torus models. Modeling AGN as an accreting supermassive black hole,
surrounded by a cylinder of dust and gas, we show a relationship between
viewing angle and the revealed area of the inner wall. From the revealed area,
we can determine the amount of FHIL emission at various angles. We calculate
the strength of [FeVII]{\lambda}6087 emission for a number of intermediate
angles (30$^{\circ}$, 40$^{\circ}$, and 50$^{\circ}$) and compare the results
with the luminosity of the observed emission line from six known CLiF AGN. We
find that there is good agreement between our model and the observational
results. The model also enables us to determine the relationship between the
type 2 : type 1 AGN fraction vs the ratio of torus height to radius, h/r.


title: Pulsar Magnetospheres: Beyond the Flat Spacetime Dipole

abstract:
  Most studies of the pulsar magnetosphere have assumed a pure magnetic dipole
in flat spacetime. However, recent work suggests that the effects of general
relativity are in fact of vital importance and that realistic pulsar magnetic
fields will have a significant nondipolar component. We introduce a general
analytical method for studying the axisymmetric force-free magnetosphere of a
slowly-rotating star of arbitrary magnetic field, mass, radius and moment of
inertia, including all the effects of general relativity. We confirm that
spacelike current is generically present in the polar caps (suggesting a pair
production region), irrespective of the stellar magnetic field. We show that
general relativity introduces a ~60% correction to the formula for the dipolar
component of the surface magnetic field inferred from spindown. Finally, we
show that the location and shape of the polar caps can be modified dramatically
by even modestly strong higher moments. This can affect emission processes
occurring near the star and may help explain the modified beam characteristics
of millisecond pulsars.


title:
The relationship between variable and polarized optical spectral
  components of luminous type 1 non-blazar quasars

abstract:
  Optical spectropolarimetry carried out by Kishimoto et al. (2004) has shown
that several luminous type 1 quasars show a strong decrease of the polarized
continuum flux in the rest-frame near-UV wavelengths of $\lambda<4000$\AA. In
the literature, this spectral feature is interpreted as evidence of the
broadened hydrogen Balmer absorption edge imprinted in the accretion disk
thermal emission due to the disk atmospheric opacity effect. On the other hand,
the quasar flux variability studies have shown that the variable continuum
component in UV-optical spectra of quasars, which is considered to be a good
indicator of the intrinsic spectral shape of the accretion disk emission,
generally have significantly flat spectral shape throughout the near-UV to
optical spectral range. To examine whether the disk continuum spectral shapes
revealed as the polarized flux and as the variable component spectra are
consistent with each other, we carry out multi-band photometric monitoring
observations for a sample of four polarization-decreasing quasars of Kishimoto
et al. (2004) (4C09.72, 3C323.1, Ton 202, and B2 1208+32) to derive the
variable component spectra and compare the spectral shape of them with that of
the polarized flux spectra. Contrary to expectation, we confirm that the two
spectral components of these quasars have totally different spectral shape in
that the variable component spectra are significantly bluer compared to the
polarized flux spectra. This discrepancy in the spectral shape may imply either
(1) the decrease of polarization degree in the rest-frame UV wavelengths is not
indicating the Balmer absorption edge feature but is induced by some unknown
(de)polarization mechanisms, or (2) the UV-optical flux variability is
occurring preferentially at the hot inner radii of the accretion disk and thus
the variable component spectra do not reflect the whole accretion disk
emission.


title:
Review of strongly-coupled composite dark matter models and lattice
  simulations

abstract:
  We review models of new physics in which dark matter arises as a composite
bound state from a confining strongly-coupled non-Abelian gauge theory. We
discuss several qualitatively distinct classes of composite candidates,
including dark mesons, dark baryons, and dark glueballs. We highlight some of
the promising strategies for direct detection, especially through dark moments,
using the symmetries and properties of the composite description to identify
the operators that dominate the interactions of dark matter with matter, as
well as dark matter self-interactions. We briefly discuss the implications of
these theories at colliders, especially the (potentially novel) phenomenology
of dark mesons in various regimes of the models. Throughout the review, we
highlight the use of lattice calculations in the study of these
strongly-coupled theories, to obtain precise quantitative predictions and new
insights into the dynamics.


title: The supernova impostor PSN J09132750+7627410 and its progenitor

abstract:
  We report the results of our follow-up campaign of the supernova impostor PSN
J09132750+7627410, based on optical data covering $\sim250\,\rm{d}$. From the
beginning, the transient shows prominent narrow Balmer lines with P-Cygni
profiles, with a blue-shifted absorption component becoming more prominent with
time. Along the $\sim3\,\rm{months}$ of the spectroscopic monitoring, broad
components are never detected in the hydrogen lines, suggesting that these
features are produced in slowly expanding material. The transient reaches an
absolute magnitude $M_r=-13.60\pm0.19\,\rm{mag}$ at maximum, a typical
luminosity for supernova impostors. Amateur astronomers provided
$\sim4\,\rm{years}$ of archival observations of the host galaxy, NGC 2748. The
detection of the quiescent progenitor star in archival images obtained with the
Hubble Space Telescope suggests it to be an $18-20$\msun white-yellow
supergiant.


title:
A Mechanism for Stimulating AGN Feedback by Lifting Gas in Massive
  Galaxies

abstract:
  Observation shows that nebular emission, molecular gas, and young stars in
giant galaxies are associated with rising X-ray bubbles inflated by radio jets
launched from nuclear black holes. We propose a model where molecular clouds
condense from low entropy gas caught in the updraft of rising X-ray bubbles.
The low entropy gas becomes thermally unstable when it is lifted to an altitude
where its cooling time is shorter than the time required to fall to its
equilibrium location in the galaxy i.e., t_c/t_I < 1. The infall speed of a
cloud is bounded by the lesser of its free-fall and terminal speeds, so that
the infall time here can exceed the the free-fall time by a significant factor.
This mechanism is motivated by ALMA observations revealing molecular clouds
lying in the wakes of rising X-ray bubbles with velocities well below their
free-fall speeds. Our mechanism would provide cold gas needed to fuel a
feedback loop while stabilizing the atmosphere on larger scales. The observed
cooling time threshold of ~ 5x 10^8 yr --- the clear-cut signature of thermal
instability and the onset of nebular emission and star formation--- may result
from the limited ability of radio bubbles to lift low entropy gas to altitudes
where thermal instabilities can ensue. Outflowing molecular clouds are unlikely
to escape, but instead return to the central galaxy in a circulating flow. We
contrast our mechanism to precipitation models where the minimum value of
t_c/t_ff < 10 triggers thermal instability, which we find to be inconsistent
with observation.


title: Disorder-Induced Entanglement in Spin Ice Pyrochlores

abstract:
  We propose that in a certain class of magnetic materials, known as
non-Kramers 'spin ice,' disorder induces quantum entanglement. Instead of
driving glassy behavior, disorder provokes quantum superpositions of spins
throughout the system, and engenders an associated emergent gauge structure and
set of fractional excitations. More precisely, disorder transforms a classical
phase governed by a large entropy, classical spin ice, into a quantum spin
liquid governed by entanglement. As the degree of disorder is increased, the
system transitions between (i) a "regular" Coulombic spin liquid, (ii) a phase
known as "Mott glass," which contains rare gapless regions in real space, but
whose behavior on long length scales is only modified quantitatively, and (iii)
a true glassy phase for random distributions with large width or large mean
amplitude.


title:
Statistical Test of Distance--Duality Relation with Type Ia Supernovae
  and Baryon Acoustic Oscillations

abstract:
  We test the distance--duality relation $\eta \equiv d_L / [ (1 + z)^2 d_A ] =
1$ between cosmological luminosity distance ($d_L$) from the JLA SNe Ia
compilation (arXiv:1401.4064) and angular-diameter distance ($d_A$) based on
Baryon Oscillation Spectroscopic Survey (BOSS; arXiv:1607.03155) and WiggleZ
baryon acoustic oscillation measurements (arXiv:1105.2862, arXiv:1204.3674).
The $d_L$ measurements are matched to $d_A$ redshift by a statistically
consistent compression procedure. With Monte Carlo methods, nontrivial and
correlated distributions of $\eta$ can be explored in a straightforward manner
without resorting to a particular evolution template $\eta(z)$. Assuming
independent constraints on cosmological parameters that are necessary to obtain
$d_L$ and $d_A$ values, we find 9% constraints consistent with $\eta = 1$ from
the analysis of SNIa + BOSS and an 18% bound results from SNIa + WiggleZ. These
results are contrary to previous claims that $\eta < 1$ has been found close to
or above the $1 \sigma$ level. We discuss the effect of different cosmological
parameter inputs and the use of the apparent deviation from distance--duality
as a proxy of systematic effects on cosmic distance measurements. The results
suggest possible systematic overestimation of SNIa luminosity distances
compared with $d_A$ data when a Planck {\Lambda}CDM cosmological parameter
inference (arXiv:1502.01589) is used to enhance the precision. If interpreted
as an extinction correction due to a gray dust component, the effect is broadly
consistent with independent observational constraints.


title:
Properties of galaxies at the faint end of the H$\alpha$ luminosity
  function at $z\sim0.62$

abstract:
  Studies measuring the star formation rate density, luminosity function, and
properties of star-forming galaxies are numerous. However, it exists a gap at
$0.5<z<0.8$ in H$\alpha$-based studies. Our main goal is to study the
properties of a sample of faint H$\alpha$ emitters at $z\sim0.62$. We focus on
their contribution to the faint end of the luminosity function and derived star
formation rate density, characterising their morphologies and basic photometric
and spectroscopic properties. We use a narrow-band technique in the
near-infrared, with a filter centred at 1.06 $\mu$m. The data come from
ultra-deep VLT/HAWK-I observations in the GOODS-S field with a total of 31.9 h
in the narrow-band filter. We perform a visual classification of the sample and
study their morphologies from structural parameters available in CANDELS. Our
28 H$\alpha$-selected sample of faint star-forming galaxies reveals a robust
faint-end slope of the luminosity function $\alpha=-1.46_{-0.08}^{+0.16}$. The
derived star formation rate density at $z\sim0.62$ is $\rho_\mathrm{SFR} =
0.036_{-0.008}^{+0.012} M_{\odot}~\mathrm{yr^{-1}~Mpc^{-3}}$. The sample is
mainly composed of disks, but an important contribution of compact galaxies
with S\'ersic indexes $n\sim2$ display the highest specific star formation
rates. The luminosity function at $z\sim0.62$ from our ultra-deep data points
towards a steeper $\alpha$ when an individual extinction correction for each
object is applied. Compact galaxies are low-mass, low-luminosity, and
starburst-dominated objects with a light profile in an intermediate stage from
early to late types.


title: Kinetics of Deposition in the Diffusion-Controlled Limit

abstract:
  The adsorption of particles diffusing in a half-space bounded by the
substrate and irreversibly sticking to the substrate upon contacts is
investigated. We show that when absorbing particles are planar disks diffusing
in the three-dimensional half-space, the coverage approaches its saturated
jamming value as $t^{-1}$ in the large time limit [generally as $t^{-1/(d-1)}$
when the substrate is $d$ dimensional and $d>1$, and as $e^{-t/\ln(t)}$ when
$d=1$]. We also analyze the asymptotic behavior when particles are spherical
and when particles are planar aligned squares.


title:
SDN Partitioning: A Centralized Control Plane for Distributed Routing
  Protocols

abstract:
  Hybrid IP networks that use both control paradigms - distributed and
centralized - promise the best of two worlds: programmability and agility of
SDN, and reliability and fault tolerance of distributed routing protocols like
OSPF. The common approaches follow a division of labor concept, where SDN
controls prioritized traffic and OSPF assures care-free operation of best
effort traffic. We propose SDN Partitioning, which establishes centralized
control over the distributed routing protocol by partitioning the topology into
sub-domains with SDN-enabled border nodes, such that OSPF's routing updates
have to traverse SDN border nodes to reach neighboring sub-domains. This allows
the central controller to modify how sub-domains view one another, which in
turn allows to steer inter-sub-domain traffic. The degree of dynamic control
against simplicity of OSPF can be trade off by adjusting the size of the
sub-domains. This paper explains the technical requirements, presents a novel
scheme for balanced topology partitioning, and provides the models for common
network management tasks. Our performance evaluation shows that - already in
its minimum configuration with two sub-domains - SDN Partitioning provides
significant improvements in all respects compared to legacy routing protocols,
whereas smaller sub-domains provide network control capabilities comparable to
full SDN deployment.


title:
EG Andromedae: A New Orbit and Additional Evidence for a Photoionized
  Wind

abstract:
  We analyze a roughly 20 yr set of spectroscopic observations for the
symbiotic binary EG And. Radial velocities derived from echelle spectra are
best-fit with a circular orbit having orbital period P = 483.3 +- 1.6 days and
semi-amplitude K = 7.34 +- 0.07 km/sec. Combined with previous data, these
observations rule out an elliptical orbit at the 10-sigma level. Equivalent
widths of H~I Balmer emission lines and various absorption features vary in
phase with the orbital period. Relative to the radius of the red giant primary,
the apparent size of the H II region is consistent with a model where a hot
secondary star with effective temperature of roughly 75,000 K ionizes the wind
from the red giant.


title: Silicate condensation in Mira variables

abstract:
  We study whether the condensation of silicate dust in Mira envelopes could be
caused by cluster formation by the abundant SiO molecules. For a simplified
model of the pulsational motions of matter in the the outer layers of a Mira
variable which is guided by a numerical model for Mira pulsations, the
equations of dust nucleation and growth are solved in the co-moving frame of a
fixed mass element. It is assumed that seed particles form by clustering of SiO
molecules. The calculation of the nucleation rate is based on the experimental
data of Nuth and Donn (1982). The quantity of dust formed is calculated by a
moment method and the calculation of radiation pressure on the dusty gas is
based on a dirty silicate model. Dust nucleation occurs in the model at the
upper culmination of the trajectory of a gas parcel where it stays for a
considerable time at low temperatures while subsequent dust growth occurs
during the descending part of the motion and continues after the next shock
reversed motion. It is found that sufficient dust forms that radiation pressure
exceeds gravitational pull of the stars such that the mass element is finally
driven out of the star. Nucleation of dust particles by clustering of the
abundant SiO molecules could be the mechanism that triggers silicate dust
formation in Miras.


title: On the Grassmann condition number

abstract:
  We give new insight into the Grassmann condition of the conic feasibility
problem \[ x \in L \cap K \setminus\{0\}. \] Here $K\subseteq V$ is a regular
convex cone and $L\subseteq V$ is a linear subspace of the finite dimensional
Euclidean vector space $V$. The Grassmann condition of this problem is the
reciprocal of the distance from $L$ to the set of ill-posed instances in the
Grassmann manifold where $L$ lives.
  We consider a very general distance in the Grassmann manifold defined by two
possibly different norms in $V$. We establish the equivalence between the
Grassmann distance to ill-posedness of the above problem and a natural measure
of the least violated trial solution to its alternative feasibility problem. We
also show a tight relationship between the Grassmann and Renegar's condition
measures, and between the Grassman measure and a symmetry measure of the above
feasibility problem.
  Our approach can be readily specialized to a canonical norm in $V$ induced by
$K$, a prime example being the one-norm for the non-negative orthant. For this
special case we show that the Grassmann distance ill-posedness of is equivalent
to a measure of the most interior solution to the above conic feasibility
problem.


title: DISTEA: Efficient Dynamic Impact Analysis for Distributed Systems

abstract:
  Dynamic impact analysis is a fundamental technique for understanding the
impact of specific program entities, or changes to them, on the rest of the
program for concrete executions. However, existing techniques are either
inapplicable or of very limited utility for distributed programs running in
multiple concurrent processes. This paper presents DISTEA, a technique and tool
for dynamic impact analysis of distributed systems. By partially ordering
distributed method-execution events and inferring causality from the ordered
events, DISTEA can predict impacts propagated both within and across process
boundaries. We implemented DISTEA for Java and applied it to four distributed
programs of various types and sizes, including two enterprise systems. We also
evaluated the precision and practical usefulness of DISTEA, and demonstrated
its application in program comprehension, through two case studies. The results
show that DISTEA is highly scalable, more effective than existing alternatives,
and instrumental to understanding distributed systems and their executions.


title: ModelWizard: Toward Interactive Model Construction

abstract:
  Data scientists engage in model construction to discover machine learning
models that well explain a dataset, in terms of predictiveness,
understandability and generalization across domains. Questions such as "what if
we model common cause Z" and "what if Y's dependence on X reverses" inspire
many candidate models to consider and compare, yet current tools emphasize
constructing a final model all at once.
  To more naturally reflect exploration when debating numerous models, we
propose an interactive model construction framework grounded in composable
operations. Primitive operations capture core steps refining data and model
that, when verified, form an inductive basis to prove model validity. Derived,
composite operations enable advanced model families, both generic and
specialized, abstracted away from low-level details.
  We prototype our envisioned framework in ModelWizard, a domain-specific
language embedded in F# to construct Tabular models. We enumerate language
design and demonstrate its use through several applications, emphasizing how
language may facilitate creation of complex models. To future engineers
designing data science languages and tools, we offer ModelWizard's design as a
new model construction paradigm, speeding discovery of our universe's
structure.


title:
Coverage Gains from the Static Cooperation of Mutually Nearest
  Neighbours

abstract:
  Cooperation in cellular networks has been recently suggested as a promising
scheme to improve system performance. In this work, clusters are formed based
on the Mutually Nearest Neighbour relation, which defines which stations
cooperate in pair and which do not. When node positions follow a Poisson Point
Process (PPP) the performance of the original clustering model can be
approximated by another one, formed by the superposition of two PPPs (one for
the singles and one for the pairs) equipped with adequate marks. This allows to
derive exact expressions for the network coverage probability under two
user-cluster association rules. Numerical evaluation shows coverage gains from
different signal cooperation schemes that can reach up to 15% compared to the
standard non-cooperative network coverage. The analysis is general and can be
applied to any type of cooperation or coordination between pairs of
transmitting nodes.


title:
Liposomes versus metallic nanostructures: differences in the process of
  knowledge translation in cancer

abstract:
  This research maps the knowledge translation process for two different types
of nanotechnologies applied to cancer: liposomes and metallic nanostructures
(MNs). We performed a structural analysis of citation networks and text mining
supported in controlled vocabularies. In the case of liposomes, our results
identify subnetworks (invisible colleges) associated with different therapeutic
strategies: nanopharmacology, hyperthermia, and gene therapy. Only in the
pharmacological strategy was an organized knowledge translation process
identified, which, however, is monopolized by the liposomal doxorubicins. In
the case of MNs, subnetworks are not differentiated by the type of therapeutic
strategy, and the content of the documents is still basic research. Research on
MNs is highly focused on developing a combination of molecular imaging and
photothermal therapy.


title: Asymptotics of Bivariate Analytic Functions with Algebraic Singularities

abstract:
  In this paper, we use the multivariate analytic techniques of Pemantle and
Wilson to derive asymptotic formulae for the coefficients of a broad class of
multivariate generating functions with algebraic singularities. Flajolet and
Odlyzko (1990) analyzed the coefficients of a class of univariate generating
functions with algebraic singularities. These results have been extended to
classes of multivariate generating functions by Gao and Richmond (1992) and
Hwang (1996, 1998), in both cases by immediately reducing the multivariate case
to the univariate case. Pemantle and Wilson (2013) outlined new multivariate
analytic techniques and used them to analyze the coefficients of rational
generating functions. These same multivariate techniques can be used to analyze
functions with algebraic singularities.


title:
Comparison of Domain Nucleation Mechanisms in a Minimal Model of Shoot
  Apical Meristem

abstract:
  Existing mathematical models of the shoot apical meristem (SAM) explain
nucleation and confinement of a stem cell domain by Turing's mechanism,
assuming that the diffusion coefficients of the activator (WUSCHEL) and
inhibitor (CLAVATA) are significantly different. As there is no evidence for
this assumption of differential diffusivity, we recently proposed a new
mechanism based on a bistable switch model of the SAM. Here we study the
bistable-switch mechanism in detail, demonstrating that it can be understood as
localized switches of WUSHEL activity in individual cells driven by a
non-uniform field of a peptide hormone. By comparing domain formation by Turing
and bistable-switch mechanisms on a cell network, we show that the latter does
not require the assumptions needed by the former, which are not supported by
biological evidences.


title: Probabilistic quantum teleportation in the presence of noise

abstract:
  We extend the research program initiated in [Phys. Rev. A 92, 012338 (2015)],
where we restricted our attention to noisy deterministic teleportation
protocols, to noisy probabilistic (conditional) protocols. Our main goal now is
to study how we can increase the fidelity of the teleported state in the
presence of noise by working with probabilistic protocols. We work with several
scenarios involving the most common types of noise in realistic implementations
of quantum communication tasks and find many cases where adding more noise to
the probabilistic protocol increases considerably the fidelity of the
teleported state, without decreasing the probability of a successful run of the
protocol. Also, there are cases where the entanglement of the channel
connecting Alice and Bob leading to the greatest fidelity is not maximal.
Moreover, there exist cases where the optimal fidelity for the probabilistic
protocols are greater than the maximal fidelity (2/3) achievable by using only
classical resources, while the optimal ones for the deterministic protocols
under the same conditions lie below this limit. This result clearly illustrates
that in some cases we can only get a truly quantum teleportation if we use
probabilistic instead of deterministic protocols.


title:
Location of the Path Supremum for Self-similar Processes with Stationary
  Increments

abstract:
  In this paper we consider the distribution of the location of the path
supremum in a fixed interval for self-similar processes with stationary
increments. To this end, a point process is constructed and its relation to the
distribution of the location of the path supremum is studied. Using this
framework, we show that the distribution has a spectral-type representation, in
the sense that it is always a mixture of a special group of absolutely
continuous distributions, plus point masses on the two boundaries. Bounds on
the value and the derivatives of the density function are established. We
further discuss self-similar L\'{e}vy processes as an example. Most of the
results in this paper can be generalized to a group of random locations,
including the location of the largest jump, etc.


title:
A note on convergence analysis of NURBS curve when weights approach
  infinity

abstract:
  This article considers the convergence of NURBS curve when weights approach
infinity. We shows that limit of NURBS curve dose not exist when independent
variables weights approach infinity. Further, pointwise convergence uniform
convergence and $L^1$ convergence are researched.


title: Sheaf and duality methods for analyzing multi-model systems

abstract:
  There is an interplay between models, specified by variables and equations,
and their connections to one another. This dichotomy should be reflected in the
abstract as well. Without referring to the models directly -- only that a model
consists of spaces and maps between them -- the most readily apparent feature
of a multi-model system is its topology. We propose that this topology should
be modeled first, and then the spaces and maps of the individual models be
specified in accordance with the topology. Axiomatically, this construction
leads to sheaves. Sheaf theory provides a toolbox for constructing predictive
models described by systems of equations. Sheaves are mathematical objects that
manage the combination of bits of local information into a consistent whole.
The power of this approach is that complex models can be assembled from
smaller, easier-to-construct models. The models discussed in this chapter span
the study of continuous dynamical systems, partial differential equations,
probabilistic graphical models, and discrete approximations of these models.


title: Theory of Exciton Energy Transfer in Carbon Nanotube Composites

abstract:
  We compute the exciton transfer (ET) rate between semiconducting single-wall
carbon nanotubes (SWNTs). We show that the main reasons for the wide range of
measured ET rates reported in the literature are 1) exciton confinement in
local quantum wells stemming from disorder in the environment and 2) exciton
thermalization between dark and bright states due to intratube scattering. The
SWNT excitonic states are calculated by solving the Bethe-Salpeter equation
using tight-binding basis functions. The ET rates due to intertube Coulomb
interaction are computed via Fermi's golden rule. In pristine samples, the ET
rate between parallel (bundled) SWNTs of similar chirality is very high ($\sim
10^{14}\;\text{s}^{-1}$) while the ET rate for dissimilar or nonparallel tubes
is considerably lower ($\sim 10^{12}\;\text{s}^{-1}$). Exciton confinement
reduces the ET rate between same-chirality parallel SWNTs by two orders of
magnitude, but has little effect otherwise. Consequently, the ET rate in most
measurements will be on the order of $ 10^{12}\;\text{s}^{-1}$, regardless of
the tube relative orientation or chirality. Exciton thermalization between
bright and dark states further reduces the ET rate to about
$10^{11}\;\text{s}^{-1}$. The ET rate also increases with increasing
temperature and decreases with increasing dielectric constant of the
surrounding medium.


title: Extracting Patterns of Urban Activity from Geotagged Social Data

abstract:
  Data generated on location-based social networks provide rich information on
the whereabouts of urban dwellers. Specifically, such data reveal who spends
time where, when, and on what type of activity (e.g., shopping at a mall, or
dining at a restaurant). That information can, in turn, be used to describe
city regions in terms of activity that takes place therein. For example, the
data might reveal that citizens visit one region mainly for shopping in the
morning, while another for dining in the evening. Furthermore, once such a
description is available, one can ask more elaborate questions: What are the
features that distinguish one region from another -- is it simply the type of
venues they host or is it the visitors they attract? What regions are similar
across cities?
  In this paper, we attempt to answer these questions using publicly shared
Foursquare data. In contrast with previous work, our method makes use of a
probabilistic model with minimal assumptions about the data and thus relieves
us from having to make arbitrary decisions in our analysis (e.g., regarding the
granularity of discovered regions or the importance of different features). We
perform an empirical comparison with previous work and discuss insights
obtained through our findings.


title: Energy degeneracies from Broad Histogram Method and Wang-Landau Sampling

abstract:
  In this work, we present a comparative study of the accuracy provided by the
Wang-Landau sampling and the Broad Histogram method to estimate de density of
states of the two dimensional Ising ferromagnet. The microcanonical averages
used to describe the thermodynamic behaviour and to use the Broad Histogram
method were obtained using the single spin-flip Wang-Landau sampling,
attempting to convergence issues and accuracy improvements. We compare the
results provided by both techniques with the exact ones for thermodynamic
properties and critical exponents. Our results, within the Wang-Landau
sampling, reveal that the Broad Histogram approach provides a better
description of the density of states for all cases analysed.


title: The Orion fingers: Near-IR spectral imaging of an explosive outflow

abstract:
  We present near-IR (1.1-2.4 micron) position-position-velocity cubes of the
500-year-old Orion BN/KL explosive outflow with spatial resolution 1" and
spectral resolution 86 km/s. We construct integrated intensity maps free of
continuum sources of 15 H2 and [Fe II] lines while preserving kinematic
information of individual outflow features. Included in the detected H2 lines
are the 1-0 S(1) and 1-0 Q(3) transitions, allowing extinction measurements
across the outflow. Additionally, we present dereddened flux ratios for over
two dozen outflow features to allow for the characterization of the true
excitation conditions of the BN/KL outflow. All ratios show the dominance of
shock excitation of the H2 emission, although some features exhibit signs of
fluorescent excitation from stellar radiation or J-type shocks. We also detect
tracers of the PDR/ionization front north of the Trapezium stars in [O I] and
[Fe II] and analyze other observed outflows not associated with the BN/KL
outflow.


title: Ap\'ery constants of homogeneous varieties

abstract:
  For Fano manifolds we define Ap\'ery constants and Ap\'ery class as
particular limits of ratios of coefficients of solutions of the quantum
differential equation. We do numerical computations in case of homogeneous
varieties. These numbers are identified to be polynomials in the values of
Riemann zeta-function with natural arguments.


title: Bags of Local Convolutional Features for Scalable Instance Search

abstract:
  This work proposes a simple instance retrieval pipeline based on encoding the
convolutional features of CNN using the bag of words aggregation scheme (BoW).
Assigning each local array of activations in a convolutional layer to a visual
word produces an \textit{assignment map}, a compact representation that relates
regions of an image with a visual word. We use the assignment map for fast
spatial reranking, obtaining object localizations that are used for query
expansion. We demonstrate the suitability of the BoW representation based on
local CNN features for instance retrieval, achieving competitive performance on
the Oxford and Paris buildings benchmarks. We show that our proposed system for
CNN feature aggregation with BoW outperforms state-of-the-art techniques using
sum pooling at a subset of the challenging TRECVid INS benchmark.


title: Spatio-temporal Models of Lymphangiogenesis in Wound Healing

abstract:
  Several studies suggest that one possible cause of impaired wound healing is
failed or insufficient lymphangiogenesis, that is the formation of new
lymphatic capillaries. Although many mathematical models have been developed to
describe the formation of blood capillaries (angiogenesis), very few have been
proposed for the regeneration of the lymphatic network. Lymphangiogenesis is a
markedly different process from angiogenesis, occurring at different times and
in response to different chemical stimuli. Two main hypotheses have been
proposed: 1) lymphatic capillaries sprout from existing interrupted ones at the
edge of the wound in analogy to the blood angiogenesis case; 2) lymphatic
endothelial cells first pool in the wound region following the lymph flow and
then, once sufficiently populated, start to form a network. Here we present two
PDE models describing lymphangiogenesis according to these two different
hypotheses. Further, we include the effect of advection due to interstitial
flow and lymph flow coming from open capillaries. The variables represent
different cell densities and growth factor concentrations, and where possible
the parameters are estimated from biological data. The models are then solved
numerically and the results are compared with the available biological
literature.


title: On Tarski's axiomatic foundations of the calculus of relations

abstract:
  It is shown that Tarski's set of ten axioms for the calculus of relations is
independent in the sense that no axiom can be derived from the remaining
axioms. It is also shown that by modifying one of Tarski's axioms slightly, and
in fact by replacing the right-hand distributive law for relative
multiplication with its left-hand version, we arrive at an equivalent set of
axioms which is redundant in the sense that one of the axioms, namely the
second involution law, is derivable from the other axioms. The set of remaining
axioms is independent. Finally, it is shown that if both the left-hand and
right-hand distributive laws for relative multiplication are included in the
set of axioms, then two of Tarski's other axioms become redundant, namely the
second involution law and the distributive law for converse. The set of
remaining axioms is independent and equivalent to Tarski's axiom system.


title: Nonparametric Estimation of ROC Surfaces Under Verification Bias

abstract:
  Verification bias is a well known problem when the predictive ability of a
diagnostic test has to be evaluated. In this paper, we discuss how to assess
the accuracy of continuous-scale diagnostic tests in the presence of
verification bias, when a three-class disease status is considered. In
particular, we propose a fully nonparametric verification bias-corrected
estimator of the ROC surface. Our approach is based on nearest-neighbor
imputation and adopts generic smooth regression models for both the disease and
the verification processes. Consistency and asymptotic normality of the
proposed estimator are proved and its finite sample behavior is investigated by
means of several Monte Carlo simulation studies. Variance estimation is also
discussed and an illustrative example is presented.


title:
On the finite convergence of the Douglas-Rachford algorithm for solving
  (not necessarily convex) feasibility problems in Euclidean spaces

abstract:
  Solving feasibility problems is a central task in mathematics and the applied
sciences. One particularly successful method is the Douglas-Rachford algorithm.
In this paper, we provide many new conditions sufficient for finite
convergence. Numerous examples illustrate our results.


title: Multi-Manifold Stark Splittings Lift the Rydberg Blockade

abstract:
  The spatial evolution of the Rydberg blockade is studied taking into account
Stark-split energy levels across several manifolds. We find that the unexpected
restoration of a blockaded Rydberg excitation at small interatomic distances,
e.g., experimentally observed by P.Schauss, et al. [Nature 491, 87 (2012)], can
be explained by the perturbed energy levels from neighboring manifolds that
enter the energy window of excitation defined by the bandwidth of the exciting
laser. The same mechanism can also explain why the pair correlation function of
Rydberg atoms remains nonzero in the entire region of Rydberg blockade.


title: Dynamic Endpoint Object Conveyance Using a Large-Scale Actuator Network

abstract:
  Large-Scale Actuator Networks (LSAN) are a rapidly growing class of
electromechanical systems. A prime application of LSANs in the industrial
sector is distributed manipulation. LSAN's are typically implemented using:
vibrating plates, air jets, and mobile multi-robot teams. This paper
investigates a surface capable of morphing its shape using an array of linear
actuators to impose two dimensional translational movement on a set of objects.
The collective nature of the actuator network overcomes the limitations of the
single Degree of Freedom (DOF) manipulators, and forms a complex topography to
convey multiple objects to a reference location. A derivation of the kinematic
constraints and limitations of an arbitrary multi-cell surface is provided.
These limitations determine the allowable actuator alignments when configuring
the surface. A fusion of simulation and practical results demonstrate the
advantages of using this technology over static feeders.


title:
Why Artificial Intelligence Needs a Task Theory --- And What It Might
  Look Like

abstract:
  The concept of "task" is at the core of artificial intelligence (AI): Tasks
are used for training and evaluating AI systems, which are built in order to
perform and automatize tasks we deem useful. In other fields of engineering
theoretical foundations allow thorough evaluation of designs by methodical
manipulation of well understood parameters with a known role and importance;
this allows an aeronautics engineer, for instance, to systematically assess the
effects of wind speed on an airplane's performance and stability. No framework
exists in AI that allows this kind of methodical manipulation: Performance
results on the few tasks in current use (cf. board games, question-answering)
cannot be easily compared, however similar or different. The issue is even more
acute with respect to artificial *general* intelligence systems, which must
handle unanticipated tasks whose specifics cannot be known beforehand. A *task
theory* would enable addressing tasks at the *class* level, bypassing their
specifics, providing the appropriate formalization and classification of tasks,
environments, and their parameters, resulting in more rigorous ways of
measuring, comparing, and evaluating intelligent behavior. Even modest
improvements in this direction would surpass the current ad-hoc nature of
machine learning and AI evaluation. Here we discuss the main elements of the
argument for a task theory and present an outline of what it might look like
for physical tasks.


title: Parallelizing Word2Vec in Shared and Distributed Memory

abstract:
  Word2Vec is a widely used algorithm for extracting low-dimensional vector
representations of words. It generated considerable excitement in the machine
learning and natural language processing (NLP) communities recently due to its
exceptional performance in many NLP applications such as named entity
recognition, sentiment analysis, machine translation and question answering.
State-of-the-art algorithms including those by Mikolov et al. have been
parallelized for multi-core CPU architectures but are based on vector-vector
operations that are memory-bandwidth intensive and do not efficiently use
computational resources. In this paper, we improve reuse of various data
structures in the algorithm through the use of minibatching, hence allowing us
to express the problem using matrix multiply operations. We also explore
different techniques to distribute word2vec computation across nodes in a
compute cluster, and demonstrate good strong scalability up to 32 nodes. In
combination, these techniques allow us to scale up the computation near
linearly across cores and nodes, and process hundreds of millions of words per
second, which is the fastest word2vec implementation to the best of our
knowledge.


title: Yang-Mills theory on noncommutative space: does it exist?

abstract:
  I revisit a basic question about the noncommutative Yang-Mills theory: if it
exists or not, or more precisely, whether a nonperturbative formulation exists.
As the most promising approach, I consider a formulation based on matrix
models. It is explained that the existence of the noncommutative Yang-Mills
theory is closely related to the Eguchi-Kawai equivalence. I argue that
supersymmetric noncommutative Yang-Mills theory can be defined
straightforwardly. Non-supersymmetric theories, such as QCD and pure bosonic
theories, can presumably be defined, by modifying the ultraviolet and infrared
behaviors appropriately.


title: Rational curves on hypersurfaces

abstract:
  Let $(X,D)$ be a pair where $X$ is a projective variety. We study in detail
how the behavior of rational curves on $X$ as well as the positivity of
$-(K_X+D)$ and $D$ influence the behavior of rational curves on $D$. In
particular we give criteria for uniruledness and rational connectedness of
components of $D$.


title: Capacitated Dominating Set on Planar Graphs

abstract:
  Capacitated Domination generalizes the classic Dominating Set problem by
specifying for each vertex a required demand and an available capacity for
covering demand in its closed neighborhood. The objective is to find a
minimum-sized set of vertices that can cover all of the graph's demand without
exceeding any of the capacities. In this paper we look specifically at
domination with hard-capacities, where the capacity and cost of a vertex can
contribute to the solution at most once. Previous complexity results suggest
that this problem cannot be solved (or even closely approximated) efficiently
in general. In this paper we present a polynomial-time approximation scheme for
Capacitated Domination in unweighted planar graphs when the maximum capacity
and maximum demand are bounded. We also show how this result can be extended to
the closely-related Capacitated Vertex Cover problem.


title:
Error estimate for a finite element approximation of the solution of a
  linear parabolic equation on a two-dimensional surface

abstract:
  We show that a certain error estimate for a fully discrete finite element
approximation of the solution of the heat equation which is defined in a
two-dimensional Euclidean domain carries over to the case of a general linear
parabolic equation which is defined on a two-dimensional surface.


title: A Convex Cauchy-Schwarz DivergenceMeasure for Blind Source Separation

abstract:
  We propose a new class of divergence measures for Independent Component
Analysis (ICA) for the demixing of multiple source mixtures. We call it the
Convex Cauchy-Schwarz Divergence (CCS-DIV), and it is formed by integrating
convex functions into the Cauchy-Schwarz inequality. The new measure is
symmetric and the degree of its curvature with respect to the
joint-distribution can be tuned by a (convexity) parameter. The CCS-DIV is able
to speed-up the search process in the parameter space and produces improved
demixing performance. An algorithm, generated from the proposed divergence, is
developed which is employing the non-parametric Parzen window-based
distribution. Simulation evidence is presented to verify and quantify its
superior performance in comparison to state-of-the art approaches.


title: Secure Mobile Identities

abstract:
  The unique identities of every mobile user (phone number,IMSI) and device
(IMEI) are far from secure and are increasingly vulnerable to a variety of
network-level threats. The exceedingly high reliance on the weak SIM
authentication layer does not present any notion of end-to-end security for
mobile users. We propose the design and implementation of Secure Mobile
Identities (SMI), a repetitive key-exchange protocol that uses this weak SIM
authentication as a foundation to enable mobile users to establish stronger
identity authenticity. The security guarantees of SMI are directly reliant on
the mobility of users and are further enhanced by external trusted entities
providing trusted location signatures (e.g. trusted GPS, NFC synchronization
points). In this paper, we demonstrate the efficacy of our protocol using an
implementation and analysis across standard mobility models.


title: Active Cancellation of Acoustical Resonances with an FPGA FIR Filter

abstract:
  We present a novel approach to enhancing the bandwidth of a
feedback-controlled mechanical system by digitally canceling acoustical
resonances (poles) and anti-resonances (zeros) in the open-loop response via an
FPGA FIR filter. By performing a real-time convolution of the feedback error
signal with an inverse filter, we can suppress arbitrarily many poles and zeros
below 100 kHz, each with a linewidth down to 10 Hz. We demonstrate the efficacy
of this technique by canceling the ten largest mechanical resonances and
anti-resonances of a high-finesse optical resonator, thereby enhancing the
unity gain frequency by more than an order of magnitude. This approach is
applicable to a broad array of stabilization problems including optical
resonators, external cavity diode lasers, and scanning tunneling microscopes,
and points the way to applying modern optimal control techniques to intricate
linear acoustical systems.es to intricate linear acoustical systems.

categories: physics.atom-ph cond-mat.quant-gas physics.ins-det physics.optics


title:
Two Pairwise Iterative Schemes For High Dimensional Blind Source
  Separation

abstract:
  This paper addresses the high dimensionality problem in blind source
separation (BSS), where the number of sources is greater than two. Two pairwise
iterative schemes are proposed to tackle this high dimensionality problem. The
two pairwise schemes realize nonparametric independent component analysis (ICA)
algorithms based on a new high-performance Convex CauchySchwarz Divergence
(CCSDIV). These two schemes enable fast and efficient demixing of sources in
real-world high dimensional source applications. Finally, the performance
superiority of the proposed schemes is demonstrated in metric-comparison with
FastICA, RobustICA, convex ICA (CICA), and other leading existing algorithms.


title:
The Faber-Jackson relation and Fundamental Plane from halo abundance
  matching

abstract:
  The Fundamental Plane (FP) describes the relation between the stellar mass,
size, and velocity dispersion of elliptical galaxies; the Faber-Jackson
relation (FJR) is its projection onto {mass, velocity} space. In this work we
redeploy and expand the framework of Desmond & Wechsler (2015) to ask whether
abundance matching-based LCDM models that have shown success in matching the
spatial distribution of galaxies are also capable of explaining key properties
of the FJR and FP, including their scatter. Within our framework, agreement
with the normalisation of the FJR requires haloes to expand in response to disc
formation. We find that the tilt of the FP may be explained by a combination of
the observed non-homology in galaxy structure and the variation in
mass-to-light ratio produced by abundance matching with a universal initial
mass function (IMF), provided that the anisotropy of stellar motions is taken
into account. However, the predicted scatter around the FP is considerably
increased by situating galaxies in cosmologically-motivated haloes due to
variations in halo properties at fixed stellar mass, and appears to exceed that
of the data. This implies that additional correlations between galaxy and halo
variables may be required to fully reconcile these models with elliptical
galaxy scaling relations.


title: Relations between entanglement and purity in non-Markovian dynamics

abstract:
  Knowledge of the relationships among different features of quantumness, like
entanglement and state purity, is important from both fundamental and practical
viewpoints. Yet, this issue remains little explored in dynamical contexts for
open quantum systems. We address this problem by studying the dynamics of
entanglement and purity for two-qubit systems using paradigmatic models of
radiation-matter interaction, with a qubit being isolated from the environment
(spectator configuration). We show the effects of the corresponding local
quantum channels on an initial two-qubit pure entangled state in the
concurrence-purity diagram and find the conditions which enable dynamical
closed formulas of concurrence, used to quantify entanglement, as a function of
purity. We finally discuss the usefulness of these relations in assessing
entanglement and purity thresholds which allow noisy quantum teleportation. Our
results provide new insights about how different properties of composite open
quantum systems behave and relate each other during quantum evolutions.


title:
On Categories of Admissible
  $\big(\mathfrak{g},\mathrm{sl}(2)\big)$-Modules

abstract:
  Let $\mathfrak{g}$ be a complex finite-dimensional semisimple Lie algebra and
$\mathfrak{k}$ be any $\mathrm{sl}(2)$-subalgebra of $\mathfrak{g}$. In this
paper we prove an earlier conjecture by Penkov and Zuckerman claiming that the
first derived Zuckerman functor provides an equivalence between a truncation of
a thick parabolic category $\mathcal{O}$ for $\mathfrak{g}$ and a truncation of
the category of admissible $(\mathfrak{g}, \mathfrak{k})-$modules. This latter
truncated category consists of admissible $(\mathfrak{g},
\mathfrak{k})-$modules with sufficiently large minimal $\mathfrak{k}$-type. We
construct an explicit functor inverse to the Zuckerman functor in this setting.
As a corollary we obtain an estimate for the global injective dimension of the
inductive completion of the truncated category of admissible $(\mathfrak{g},
\mathfrak{k})-$modules.


title: Evolutionary Projection Selection for Radon Barcodes

abstract:
  Recently, Radon transformation has been used to generate barcodes for tagging
medical images. The under-sampled image is projected in certain directions, and
each projection is binarized using a local threshold. The concatenation of the
thresholded projections creates a barcode that can be used for tagging or
annotating medical images. A small number of equidistant projections, e.g., 4
or 8, is generally used to generate short barcodes. However, due to the diverse
nature of digital images, and since we are only working with a small number of
projections (to keep the barcode short), taking equidistant projections may not
be the best course of action. In this paper, we proposed to find $n$ optimal
projections, whereas $n\!<\!180$, in order to increase the expressiveness of
Radon barcodes. We show examples for the exhaustive search for the simple case
when we attempt to find 4 best projections out of 16 equidistant projections
and compare it with the evolutionary approach in order to establish the benefit
of the latter when operating on a small population size as in the case of
micro-DE. We randomly selected 10 different classes from IRMA dataset (14,400
x-ray images in 58 classes) and further randomly selected 5 images per class
for our tests.


title: Tropical Fermat-Weber points

abstract:
  In a metric space, the Fermat-Weber points of a sample are statistics to
measure the central tendency of the sample and it is well-known that the
Fermat-Weber point of a sample is not necessarily unique in the metric space.
We investigate the computation of Fermat-Weber points under the tropical metric
on the quotient space $\mathbb{R}^{n} \!/ \mathbb{R} {\bf 1}$ with a fixed $n
\in \mathbb{N}$, motivated by its application to the space of equidistant
phylogenetic trees with $N$ leaves (in this case $n=\binom{N}{2}$) realized as
the tropical linear space of all ultrametrics. We show that the set of all
tropical Fermat-Weber points of a finite sample is always a classical convex
polytope, and we present a combinatorial formula for a key value associated to
this set. We identify conditions under which this set is a singleton. We apply
numerical experiments to analyze the set of the tropical Fermat-Weber points
within a space of phylogenetic trees. We discuss the issues in the computation
of the tropical Fermat-Weber points.


title: Radon Features and Barcodes for Medical Image Retrieval via SVM

abstract:
  For more than two decades, research has been performed on content-based image
retrieval (CBIR). By combining Radon projections and the support vector
machines (SVM), a content-based medical image retrieval method is presented in
this work. The proposed approach employs the normalized Radon projections with
corresponding image category labels to build an SVM classifier, and the Radon
barcode database which encodes every image in a binary format is also generated
simultaneously to tag all images. To retrieve similar images when a query image
is given, Radon projections and the barcode of the query image are generated.
Subsequently, the k-nearest neighbor search method is applied to find the
images with minimum Hamming distance of the Radon barcode within the same class
predicted by the trained SVM classifier that uses Radon features. The
performance of the proposed method is validated by using the IRMA 2009 dataset
with 14,410 x-ray images in 57 categories. The results demonstrate that our
method has the capacity to retrieve similar responses for the correctly
identified query image and even for those mistakenly classified by SVM. The
approach further is very fast and has low memory requirement.


title:
Generating Binary Tags for Fast Medical Image Retrieval Based on
  Convolutional Nets and Radon Transform

abstract:
  Content-based image retrieval (CBIR) in large medical image archives is a
challenging and necessary task. Generally, different feature extraction methods
are used to assign expressive and invariant features to each image such that
the search for similar images comes down to feature classification and/or
matching. The present work introduces a new image retrieval method for medical
applications that employs a convolutional neural network (CNN) with recently
introduced Radon barcodes. We combine neural codes for global classification
with Radon barcodes for the final retrieval. We also examine image search based
on regions of interest (ROI) matching after image retrieval. The IRMA dataset
with more than 14,000 x-rays images is used to evaluate the performance of our
method. Experimental results show that our approach is superior to many
published works.


title:
Sentence-Level Grammatical Error Identification as Sequence-to-Sequence
  Correction

abstract:
  We demonstrate that an attention-based encoder-decoder model can be used for
sentence-level grammatical error identification for the Automated Evaluation of
Scientific Writing (AESW) Shared Task 2016. The attention-based encoder-decoder
models can be used for the generation of corrections, in addition to error
identification, which is of interest for certain end-user applications. We show
that a character-based encoder-decoder model is particularly effective,
outperforming other results on the AESW Shared Task on its own, and showing
gains over a word-based counterpart. Our final model--a combination of three
character-based encoder-decoder models, one word-based encoder-decoder model,
and a sentence-level CNN--is the highest performing system on the AESW 2016
binary prediction Shared Task.


title: Anatomy-Aware Measurement of Segmentation Accuracy

abstract:
  Quantifying the accuracy of segmentation and manual delineation of organs,
tissue types and tumors in medical images is a necessary measurement that
suffers from multiple problems. One major shortcoming of all accuracy measures
is that they neglect the anatomical significance or relevance of different
zones within a given segment. Hence, existing accuracy metrics measure the
overlap of a given segment with a ground-truth without any anatomical
discrimination inside the segment. For instance, if we understand the rectal
wall or urethral sphincter as anatomical zones, then current accuracy measures
ignore their significance when they are applied to assess the quality of the
prostate gland segments. In this paper, we propose an anatomy-aware measurement
scheme for segmentation accuracy of medical images. The idea is to create a
``master gold'' based on a consensus shape containing not just the outline of
the segment but also the outlines of the internal zones if existent or
relevant. To apply this new approach to accuracy measurement, we introduce the
anatomy-aware extensions of both Dice coefficient and Jaccard index and
investigate their effect using 500 synthetic prostate ultrasound images with 20
different segments for each image. We show that through anatomy-sensitive
calculation of segmentation accuracy, namely by considering relevant anatomical
zones, not only the measurement of individual users can change but also the
ranking of users' segmentation skills may require reordering.


title: Hidden sign-changing $s$-wave superconductivity in monolayer FeSe

abstract:
  Combining the recent scanning tunneling microscopy (STM) and angle-resolved
photoemission spectroscopy (ARPES) measurements, we construct a tight-binding
model suitable for describing the band structure of monolayer FeSe grown on
SrTiO$_{3}$. Then we propose a possible pairing function, which can well
describe the gap anisotropy observed by ARPES and has a hidden sign-changing
characteristic. At last, as a test of this pairing function we further study
the nonmagnetic impurity-induced bound states, to be verified by future STM
experiments.


title: On the functional form of the infinite square well model

abstract:
  The original model of the infinite square well contains a vague notation
infinity and therefore results some ambiguities. We investigate to obtain a
functional form for the potential energy V(x). This is done by substituting
back the original energy eigenstates and eigenvalues into the Schrodinger
equation. We then obtain a precise functional form of the V(x). From this
reformed model, we show that energy eigenstates and eigenvalues can directly be
obtained without the need of imposing boundary condition, Ehrenfest's theorem
can directly be confirmed, and ambiguities in the original model can be
resolved.


title: Ion-wake Field inside a Glass Box

abstract:
  The confinement provided by a glass box is proving ideal for the formation of
vertically aligned structures and a convenient method for controlling the
number of dust particles comprising these dust structures, as well as their
size and shape. In this paper, the electronic confinement of the glass box is
mapped and the particle interactions between the particle pairs inside the
glass box are measured. The ion-wake field is shown to exist within the glass
box and its vertical and horizontal extent is measured.


title: A note on Dickson polynomials of the third kind and Legendre functions

abstract:
  In this paper, we show that the Dickson polynomials of the third kind satisfy
a nonhomogeneous second order linear ordinary differential equation whose
general solution contains Legendre functions.


title: Brain and Cognitive Reserve: Translation via Network Control Theory

abstract:
  Traditional approaches to understanding the brain's resilience to
neuropathology have identified neurophysiological variables, often described as
brain or cognitive 'reserve,' associated with better outcomes. However,
mechanisms of function and resilience in large-scale brain networks remain
poorly understood. Dynamic network theory may provide a basis for substantive
advances in understanding functional resilience in the human brain. In this
perspective, we describe recent theoretical approaches from network control
theory as a framework for investigating network level mechanisms underlying
cognitive function and the dynamics of neuroplasticity in the human brain. We
describe the theoretical opportunities offered by the application of network
control theory at the level of the human connectome to understand cognitive
resilience and inform translational intervention.


title:
Channel Impulse Responses in Diffusive Molecular Communication with
  Spherical Transmitters

abstract:
  Molecular communication is an emerging paradigm for systems that rely on the
release of molecules as information carriers. Communication via molecular
diffusion is a popular strategy that is ubiquitous in nature and very fast over
distances on the order of a micron or less. Existing closed-form analysis of
the diffusion channel impulse response generally assumes that the transmitter
is a point source. In this paper, channel impulse responses are derived for
spherical transmitters with either a passive or absorbing receiver. The derived
channel impulse responses are in closed-form for a one-dimensional environment
and can be found via numerical integration for a three-dimensional environment.
The point transmitter assumption (PTA) is formally defined so that its accuracy
can be measured in comparison to the derived spherical transmitter impulse
responses. The spherical transmitter model is much more accurate than the PTA
when the distance between a transmitter and its receiver is small relative to
the size of the transmitter. The derived results are verified via microscopic
particle-based simulations using the molecular communication simulation
platform AcCoRD (Actor-based Communication via Reaction-Diffusion). A spherical
transmitter variation where molecules are released from the surface of a solid
sphere is also considered via simulation.


title:
Uniform error bounds of a finite difference method for the Zakharov
  system in the subsonic limit regime via an asymptotic consistent formulation

abstract:
  We present a uniformly accurate finite difference method and establish
rigorously its uniform error bounds for the Zakharov system (ZS) with a
dimensionless parameter $0<\varepsilon\le 1$, which is inversely proportional
to the speed of sound. In the subsonic limit regime, i.e., $0<\varepsilon\ll
1$, the solution propagates highly oscillatory waves and/or rapid outgoing
initial layers due to the perturbation of the wave operator in ZS and/or the
incompatibility of the initial data which is characterized by two nonnegative
parameters $\alpha$ and $\beta$. Specifically, the solution propagates waves
with $O(\varepsilon)$- and $O(1)$-wavelength in time and space, respectively,
and amplitude at $O(\varepsilon^{\min\{2,\alpha,1+\beta\}})$ and
$O(\varepsilon^\alpha)$ for well-prepared ($\alpha\ge1$) and ill-prepared
($0\le \alpha<1$) initial data, respectively. This high oscillation of the
solution in time brings significant difficulties in designing numerical methods
and establishing their error bounds, especially in the subsonic limit regime. A
uniformly accurate finite difference method is proposed by reformulating ZS
into an asymptotic consistent formulation and adopting an integral
approximation of the oscillatory term. By adapting the energy method and using
the limiting equation via a nonlinear Schr\"{o}dinger equation with an
oscillatory potential, we rigorously establish two independent error bounds and
obtain error bounds at $O(h^2+\tau^{4/3})$ and
$O(h^2+\tau^{1+\frac{\alpha}{2+\alpha}})$ for well-prepared and ill-prepared
initial data, respectively, which are uniform in both space and time for
$0<\varepsilon\le 1$ and optimal at the second order in space. Numerical
results are reported to demonstrate that our error bounds are sharp.


title:
An upper bound for the size of a $k$-uniform intersecting family with
  covering number $k$

abstract:
  Let $r(k)$ denote the maximum number of edges in a $k$-uniform intersecting
family with covering number $k$. Erd\H{o}s and Lov\'asz proved that $ \lfloor
k! (e-1) \rfloor \leq r(k) \leq k^k.$ Frankl, Ota, and Tokushige improved the
lower bound to $r(k) \geq \left( k/2 \right)^{k-1}$, and Tuza improved the
upper bound to $r(k) \leq (1-e^{-1}+o(1))k^k$. We establish that $ r(k) \leq (1
+ o(1)) k^{k-1}$.


title:
Insights from Machine Learning for Evaluating Production Function
  Estimators on Manufacturing Survey Data

abstract:
  Organizations like U.S. Census Bureau rely on non-exhaustive surveys to
estimate industry-level production functions in years in which a full Census is
not conducted. When analyzing data from non-census years, we propose selecting
an estimator based on a weighting of its in-sample and predictive performance.
We compare Cobb-Douglas functional assumptions to existing nonparametric shape
constrained estimators and a newly proposed estimator. For simulated data, we
find that our proposed estimator has the lowest weighted errors. For actual
data, specifically the 2010 Chilean Annual National Industrial Survey, a
Cobb-Douglas specification describes at least 90\% as much variance as the best
alternative estimators in practically all cases considered providing two
insights: the benefits of using application data for selecting an estimator,
and the benefits of structure in noisy data.


title:
A broadband Ferromagnetic Resonance dipper probe for magnetic damping
  measurements from 4.2 K to 300 K

abstract:
  A dipper probe for broadband Ferromagnetic Resonance (FMR) operating from 4.2
K to room temperature is described. The apparatus is based on a 2-port
transmitted microwave signal measurement with a grounded coplanar waveguide.
The waveguide generates a microwave field and records the sample response. A
3-stage dipper design is adopted for fast and stable temperature control. The
temperature variation due to FMR is in the milli-Kelvin range at liquid helium
temperature. We also designed a novel FMR probe head with a spring-loaded
sample holder. Improved signal-to-noise ratio and stability compared to a
common FMR head are achieved. Using a superconducting vector magnet we
demonstrate Gilbert damping measurements on two thin film samples using a
vector network analyzer with frequency up to 26 GHz: 1) A Permalloy film of 5
nm thickness and 2) a CoFeB film of 1.5 nm thickness. Experiments were
performed with the applied magnetic field parallel and perpendicular to the
film plane.


title: A Parallel Solution to Finding Nodal Neighbors in Generic Meshes

abstract:
  In this paper we specifically present a parallel solution to finding the
one-ring neighboring nodes and elements for each vertex in generic meshes. The
finding of nodal neighbors is computationally straightforward but expensive for
large meshes. To improve the efficiency, the parallelism is adopted by
utilizing the modern Graphics Processing Unit (GPU). The presented parallel
solution is heavily dependent on the parallel sorting, scan, and reduction, and
can be applied to determine both the neighboring nodes and elements. To
evaluate the performance, the parallel solution is compared to the
corresponding serial solution. Experimental results show that: our parallel
solution can achieve the speedups of approximately 55 and 90 over the
corresponding serial solution for finding neighboring nodes and elements,
respectively. Our parallel solution is efficient and easy to implement, but
requires the allocation of large device memory.


title:
$SO(2)$-induced breathing patterns in multi-component Bose-Einstein
  condensates

abstract:
  In this work, we employ the $SO(2)$-rotations of a two-component, one-, two-
and three-dimensional nonlinear Schr\"{o}dinger system at and near the Manakov
limit, to construct vector solitons and vortex structures. This way, stable
stationary dark-bright solitons and their higher-dimensional siblings are
transformed into robust oscillatory dark-dark solitons (and generalizations
thereof), with and without a harmonic confinement. By analogy to the
one-dimensional case, vector higher-dimensional structures take the form of
vortex-vortex states in two dimensions and, e.g., vortex ring-vortex ring ones
in three dimensions. We consider the effects of unequal (self- and cross-)
interaction strengths, where the $SO(2)$ symmetry is only approximately
satisfied, showing the dark-dark soliton oscillation is generally robust.
Similar features are found in higher dimensions too, although our case examples
suggest that phenomena such as phase separation may contribute to the
associated dynamics. These results, in connection with the experimental
realization of one-dimensional variants of such states in optics and
Bose-Einstein condensates (BECs), suggest the potential observation of the
higher-dimensional bound states proposed herein.


title:
Constructing valid density matrices on an NMR quantum information
  processor via maximum likelihood estimation

abstract:
  Estimation of quantum states is one of the most important steps in any
quantum information processing experiment. A naive reconstruction of the
density matrix from experimental measurements can often give density matrices
which are not positive, and hence not physically acceptable. How do we ensure
that at all stages of reconstruction, we keep the density matrix positive and
normalized? Recently a method has been suggested based on maximum likelihood
estimation, wherein the density matrix is guaranteed to be positive definite.
We experimentally implement this protocol and demonstrate its utility on an NMR
quantum information processor. We discuss several examples where we undertake
such an estimation and compare it with the standard method of state estimation.


title: Micropolarity-Ramification of Laminar/Turbulent Circular-Plane-Jet

abstract:
  In the present work we formulated the boundary-value-problem, comprising
partial differential equations (PDEs) of steady flow for laminar/turbulent
circular jet of a micropolar fluid. A new boundary layer-similarity
transformation/solution was derived which is valid not only for the Newtonian
fluids but also for the micropolar fluids. Through this transformation PDEs are
transformed into the ordinary differential equations (ODEs). These ODEs were
solved numerically by the finite-difference method. The obtained results were
compared with existing results [9] for the Newtonian fluids. The comparison was
favourable. The micropolarity influences were highlighted in the present work.
The axial-fluid-speed and normal stress-component decreases but
radial-fluid-speed, microspin and one of the normal stress-component increase
as the micropolarity effect enhances. The fluid-speed, microspin, shear
stresses, normal stresses and couple stresses are dominant in the vicinity of
the jet-source whereas they all vanish as far away from the jet-source
analogous to the plane-jet-flow [8]. In addition, axial-speed, discharge,
microspin, shear stresses and the components of couple stress intensify with z
linearly but radial velocity, normal stresses and the component of couple
stress are independent of z. The micropolarity-effects on discharge diminish if
the diameter of jet-source reduces. Analogous to the plane-jet-flow [8],
teace(stress tensor)=0, for the micropolar as well as for the Newtonian fluids.
The normal stresses decreases as r goes on increasing, analogous to the
shear-stresses. But all the normal components of the couple stress tensor
vanish. The couple stress tensor is symmetric and skew-symmetric if analogous
to the plane-jet flow [8]. Finally the fluid-speed will also intensify if
turbulent-influences are enhanced.


title:
Subcategory-aware Convolutional Neural Networks for Object Proposals and
  Detection

abstract:
  In CNN-based object detection methods, region proposal becomes a bottleneck
when objects exhibit significant scale variation, occlusion or truncation. In
addition, these methods mainly focus on 2D object detection and cannot estimate
detailed properties of objects. In this paper, we propose subcategory-aware
CNNs for object detection. We introduce a novel region proposal network that
uses subcategory information to guide the proposal generating process, and a
new detection network for joint detection and subcategory classification. By
using subcategories related to object pose, we achieve state-of-the-art
performance on both detection and pose estimation on commonly used benchmarks.


title:
How graphene flexes and stretches under concomitant bending couples and
  tractions

abstract:
  We propose a geometrically and physically nonlinear discrete mechanical model
of graphene that assigns an energetic cost to changes in bond lengths, bond
angles, and dihedral angles. We formulate a variational equilibrium problem for
a rectangular graphene sheet with assigned balanced forces and couples
uniformly distributed over opposite side pairs. We show that the resulting
combination of stretching and bending makes achiral graphene easier to bend and
harder (easier) to stretch for small (large) traction loads. Our general
developments hold for a wide class of REBO potentials; we illustrate them in
detail by numerical calculations performed in the case of a widely used
2nd-generation Brenner potential.


title: On the Complexity and Performance of Parsing with Derivatives

abstract:
  Current algorithms for context-free parsing inflict a trade-off between ease
of understanding, ease of implementation, theoretical complexity, and practical
performance. No algorithm achieves all of these properties simultaneously.
  Might et al. (2011) introduced parsing with derivatives, which handles
arbitrary context-free grammars while being both easy to understand and simple
to implement. Despite much initial enthusiasm and a multitude of independent
implementations, its worst-case complexity has never been proven to be better
than exponential. In fact, high-level arguments claiming it is fundamentally
exponential have been advanced and even accepted as part of the folklore.
Performance ended up being sluggish in practice, and this sluggishness was
taken as informal evidence of exponentiality.
  In this paper, we reexamine the performance of parsing with derivatives. We
have discovered that it is not exponential but, in fact, cubic. Moreover,
simple (though perhaps not obvious) modifications to the implementation by
Might et al. (2011) lead to an implementation that is not only easy to
understand but also highly performant in practice.


title: Phone-based Metric as a Predictor for Basic Personality Traits

abstract:
  Basic personality traits are typically assessed through questionnaires. Here
we consider phone-based metrics as a way to asses personality traits. We use
data from smartphones with custom data-collection software distributed to 730
individuals. The data includes information about location, physical motion,
face-to-face contacts, online social network friends, text messages and calls.
The data is further complemented by questionnaire-based data on basic
personality traits. From the phone-based metrics, we define a set of behavioral
variables, which we use in a prediction of basic personality traits. We find
that predominantly, the Big Five personality traits extraversion and, to some
degree, neuroticism are strongly expressed in our data. As an alternative to
the Big Five, we investigate whether other linear combinations of the 44
questions underlying the Big Five Inventory are more predictable. In a tertile
classification problem, basic dimensionality reduction techniques, such as
independent component analysis, increase the predictability relative to the
baseline from $11\%$ to $23\%$. Finally, from a supervised linear classifier,
we were able to further improve this predictability to $33\%$. In all cases,
the most predictable projections had an overweight of the questions related to
extraversion and neuroticism. In addition, our findings indicate that the score
system underlying the Big Five Inventory disregards a part of the information
available in the 44 questions.