title: Stochastic dominance and the bijective ratio of online algorithms

abstract:
  Stochastic dominance is a technique for evaluating the performance of online
algorithms that provides an intuitive, yet powerful stochastic order between
the compared algorithms. Accordingly this holds for bijective analysis, which
can be interpreted as stochastic dominance assuming the uniform distribution
over requests. These techniques have been applied to some online problems, and
have provided a clear separation between algorithms whose performance varies
significantly in practice. However, there are situations in which they are not
readily applicable due to the fact that they stipulate a stringent relation
between the compared algorithms.
  In this paper, we propose remedies for these shortcomings. First, we
establish sufficient conditions that allow us to prove the bijective optimality
of a certain class of algorithms for a wide range of problems; we demonstrate
this approach in the context of some well-studied online problems. Second, to
account for situations in which two algorithms are incomparable or there is no
clear optimum, we introduce the bijective ratio as a natural extension of
(exact) bijective analysis. Our definition readily generalizes to stochastic
dominance. This renders the concept of bijective analysis (and that of
stochastic dominance) applicable to all online problems, and allows for the
incorporation of other useful techniques such as amortized analysis. We
demonstrate the applicability of the bijective ratio to one of the fundamental
online problems, namely the continuous $k$-server problem on metrics such as
the line, the circle, and the star. Among other results, we show that the
greedy algorithm attains bijective ratios of $O(k)$ consistently across these
metrics. These results confirm extensive previous studies that gave evidence of
the efficiency of this algorithm on said metrics in practice, which, however,
is not reflected in competitive analysis.


title: Stochastic Ising model with plastic interactions

abstract:
  We propose a new model based on the Ising model with the aim to study
synaptic plasticity phenomena in neural networks. It is today well established
in biology that the synapses or connections between certain types of neurons
are strengthened when the neurons are co-active, a form of the so called
synaptic plasticity. Such mechanism is believed to mediate the formation and
maintenance of memories. The proposed model describes some features from that
phenomenon. Together with the spin-flip dynamics, in our model the coupling
constants are also subject to stochastic dynamics, so that they interact with
each other. The evolution of the system is described by a continuous-time
Markov jump process.
  Keyword Markov chain, Stochastic Ising model, synaptic plasticity, neural
networks, transience


title:
Study of $B_c^+$ decays to the $K^+K^-\pi^+$ final state and evidence
  for the decay $B_c^+\to\chi_{c0}\pi^+$

abstract:
  A study of $B_c^+\to K^+K^-\pi^+$ decays is performed for the first time
using data corresponding to an integrated luminosity of 3.0 $\mathrm{fb}^{-1}$
collected by the LHCb experiment in $pp$ collisions at centre-of-mass energies
of $7$ and $8$ TeV. Evidence for the decay $B_c^+\to\chi_{c0}(\to K^+K^-)\pi^+$
is reported with a significance of 4.0 standard deviations, resulting in the
measurement of
$\frac{\sigma(B_c^+)}{\sigma(B^+)}\times\mathcal{B}(B_c^+\to\chi_{c0}\pi^+)$ to
be $(9.8^{+3.4}_{-3.0}(\mathrm{stat})\pm 0.8(\mathrm{syst}))\times 10^{-6}$.
Here $\mathcal{B}$ denotes a branching fraction while $\sigma(B_c^+)$ and
$\sigma(B^+)$ are the production cross-sections for $B_c^+$ and $B^+$ mesons.
An indication of $\bar b c$ weak annihilation is found for the region
$m(K^-\pi^+)<1.834\mathrm{\,Ge\kern -0.1em V\!/}c^2$, with a significance of
2.4 standard deviations.


title: Homogeneous families on trees and subsymmetric basic sequences

abstract:
  We study density requirements on a given Banach space that guarantee the
existence of subsymmetric basic sequences by extending Tsirelson's well-known
space to larger index sets. We prove that for every cardinal $\kappa$ smaller
than the first Mahlo cardinal there is a reflexive Banach space of density
$\kappa$ without subsymmetric basic sequences. As for Tsirelson's space, our
construction is based on the existence of a rich collection of homogeneous
families on large index sets for which one can estimate the complexity on any
given infinite set. This is used to describe detailedly the asymptotic
structure of the spaces. The collections of families are of independent
interest and their existence is proved inductively. The fundamental stepping up
argument is the analysis of such collections of families on trees.


title: Eliminating Depth Cycles among Triangles in Three Dimensions

abstract:
  Given $n$ pairwise openly disjoint triangles in 3-space, their vertical depth
relation may contain cycles. We show that, for any $\varepsilon>0$, the
triangles can be cut into $O(n^{3/2+\varepsilon})$ connected semi-algebraic
pieces, whose description complexity depends only on the choice of
$\varepsilon$, such that the depth relation among these pieces is now a proper
partial order. This bound is nearly tight in the worst case. We are not aware
of any previous study of this problem, in this full generality, with a
subquadratic bound on the number of pieces.
  This work extends the recent study by two of the authors (Aronov,
Sharir~2018) on eliminating depth cycles among lines in 3-space. Our approach
is again algebraic, and makes use of a recent variant of the polynomial
partitioning technique, due to Guth, which leads to a recursive procedure for
cutting the triangles. In contrast to the case of lines, our analysis here is
considerably more involved, due to the two-dimensional nature of the objects
being cut, so additional tools, from topology and algebra, need to be brought
to bear.
  Our result essentially settles a 35-year-old open problem in computational
geometry, motivated by hidden-surface removal in computer graphics.


title:
A microwave interferometer of the Michelson-type to improve the dynamic
  range of broadband ferromagnetic resonance measurements

abstract:
  We present a Michelson-type microwave interferometer for use in ferromagnetic
resonance experiments. The interferometer is capable of broadband operation
without manual adjustment of phase delay or amplitude attenuation. A prototype
of the design shows significant improvement of the signal-to-noise ratio when
compared to non-interferometric ferromagnetic resonance experiments. We
demonstrate that this increase in sensitivity can lead to a drastic increase in
the data acquisition rate for hard-to-measure thin films that otherwise would
require long integration times.


title: Dappled tiling

abstract:
  We consider a certain tiling problem of a planar region in which there are no
long horizontal or vertical strips consisting of copies of the same tile.
Intuitively speaking, we would like to create a dappled pattern with two or
more kinds of tiles. We give an efficient algorithm to turn any tiling into one
satisfying the condition, and discuss its applications in texturing.


title: A Complexity-Based Hierarchy for Multiprocessor Synchronization

abstract:
  For many years, Herlihy's elegant computability based Consensus Hierarchy has
been our best explanation of the relative power of various types of
multiprocessor synchronization objects when used in deterministic algorithms.
However, key to this hierarchy is treating synchronization instructions as
distinct objects, an approach that is far from the real-world, where
multiprocessor programs apply synchronization instructions to collections of
arbitrary memory locations. We were surprised to realize that, when considering
instructions applied to memory locations, the computability based hierarchy
collapses. This leaves open the question of how to better capture the power of
various synchronization instructions.
  In this paper, we provide an approach to answering this question. We present
a hierarchy of synchronization instructions, classified by their space
complexity in solving obstruction-free consensus. Our hierarchy provides a
classification of combinations of known instructions that seems to fit with our
intuition of how useful some are in practice, while questioning the
effectiveness of others. We prove an essentially tight characterization of the
power of buffered read and write instructions.Interestingly, we show a similar
result for multi-location atomic assignments.


title:
A Haar Wavelet-Based Perceptual Similarity Index for Image Quality
  Assessment

abstract:
  In most practical situations, the compression or transmission of images and
videos creates distortions that will eventually be perceived by a human
observer. Vice versa, image and video restoration techniques, such as
inpainting or denoising, aim to enhance the quality of experience of human
viewers. Correctly assessing the similarity between an image and an undistorted
reference image as subjectively experienced by a human viewer can thus lead to
significant improvements in any transmission, compression, or restoration
system. This paper introduces the Haar wavelet-based perceptual similarity
index (HaarPSI), a novel and computationally inexpensive similarity measure for
full reference image quality assessment. The HaarPSI utilizes the coefficients
obtained from a Haar wavelet decomposition to assess local similarities between
two images, as well as the relative importance of image areas. The consistency
of the HaarPSI with the human quality of experience was validated on four large
benchmark databases containing thousands of differently distorted images. On
these databases, the HaarPSI achieves higher correlations with human opinion
scores than state-of-the-art full reference similarity measures like the
structural similarity index (SSIM), the feature similarity index (FSIM), and
the visual saliency-based index (VSI). Along with the simple computational
structure and the short execution time, these experimental results suggest a
high applicability of the HaarPSI in real world tasks.


title: Strong Hardness of Privacy from Weak Traitor Tracing

abstract:
  Despite much study, the computational complexity of differential privacy
remains poorly understood. In this paper we consider the computational
complexity of accurately answering a family $Q$ of statistical queries over a
data universe $X$ under differential privacy. A statistical query on a dataset
$D \in X^n$ asks "what fraction of the elements of $D$ satisfy a given
predicate $p$ on $X$?" Dwork et al. (STOC'09) and Boneh and Zhandry (CRYPTO'14)
showed that if both $Q$ and $X$ are of polynomial size, then there is an
efficient differentially private algorithm that accurately answers all the
queries, and if both $Q$ and $X$ are exponential size, then under a plausible
assumption, no efficient algorithm exists.
  We show that, under the same assumption, if either the number of queries or
the data universe is of exponential size, and the other has size at least
$\tilde{O}(n^7)$, then there is no differentially private algorithm that
answers all the queries. In both cases, the result is nearly quantitatively
tight, since there is an efficient differentially private algorithm that
answers $\tilde{\Omega}(n^2)$ queries on an exponential size data universe, and
one that answers exponentially many queries on a data universe of size
$\tilde{\Omega}(n^2)$.
  Our proofs build on the connection between hardness results in differential
privacy and traitor-tracing schemes (Dwork et al., STOC'09; Ullman, STOC'13).
We prove our hardness result for a polynomial size query set (resp., data
universe) by showing that they follow from the existence of a special type of
traitor-tracing scheme with very short ciphertexts (resp., secret keys), but
very weak security guarantees, and then constructing such a scheme.


title:
Dynamics of particle sedimentation in viscoelastic fluids: A numerical
  study on particle chain in two-dimensional narrow channel

abstract:
  In this article we present a numerical method for simulating the
sedimentation of circular particles in two-dimensional channel filled with a
viscoelastic fluid of FENE-CR type, which is generalized from a
domain/distributed Lagrange multiplier method with a factorization approach for
Oldroyd-B fluids developed in [J. Non-Newtonian Fluid Mech. 156 (2009) 95].
Numerical results suggest that the polymer extension limit L for the FENE-CR
fluid has no effect on the final formation of vertical chain for the cases of
two disks and three disks in two-dimensional narrow channel, at least for the
values of L considered in this article; but the intermediate dynamics of
particle interaction before having a vertical chain can be different for the
smaller values of L when increasing the relaxation time. For the cases of six
particles sedimenting in FENE-CR type viscoelastic fluid, the formation of
chain of 4 to 6 disks does depend on the polymer extension limit L. For the
smaller values of L, FENE-CR type viscoelastic fluid can not bring them
together like the case of these particles settling in a vertical chain
formation in Oldroyd-B fluid; but two separated chains of three disks are
formed. Similar results for the case of ten disks are also obtained. The
numerical results of several more particle cases suggest that for smaller
values of L, the length of the vertical chain is shorter and the size of
cluster is smaller.


title:
Improved bounds on the decoding failure probability of network coding
  over multi-source multi-relay networks

abstract:
  This paper considers a multi-source multi-relay network, in which relay nodes
employ a coding scheme based on random linear network coding on source packets
and generate coded packets. If a destination node collects enough coded
packets, it can recover the packets of all source nodes. The links between
source-to-relay nodes and relay-to-destination nodes are modeled as packet
erasure channels. Improved bounds on the probability of decoding failure are
presented, which are markedly close to simulation results and notably better
than previous bounds. Examples demonstrate the tightness and usefulness of the
new bounds over the old bounds.


title: Learning the Roots of Visual Domain Shift

abstract:
  In this paper we focus on the spatial nature of visual domain shift,
attempting to learn where domain adaptation originates in each given image of
the source and target set. We borrow concepts and techniques from the CNN
visualization literature, and learn domainnes maps able to localize the degree
of domain specificity in images. We derive from these maps features related to
different domainnes levels, and we show that by considering them as a
preprocessing step for a domain adaptation algorithm, the final classification
performance is strongly improved. Combined with the whole image representation,
these features provide state of the art results on the Office dataset.


title:
The new high field photoexcitation muon spectrometer at the ISIS pulsed
  neutron and muon source

abstract:
  A high power pulsed laser system has been installed on the high magnetic
field muon spectrometer (HiFi) at the ISIS pulsed neutron and muon source,
situated at the STFC Rutherford Appleton Laboratory in the UK. The upgrade
enables one to perform light-pump muon-probe experiments under a high magnetic
field, which opens new applications of muon spin spectroscopy. In this report
we give an overview of the principle of the HiFi Laser system, and describe the
newly developed techniques and devices that enable precisely controlled
photoexcitation of samples in the muon instrument. A demonstration experiment
illustrates the potential of this unique combination of the photoexcited system
and avoided level crossing technique.


title: Supervised quantum gate "teaching" for quantum hardware design

abstract:
  We show how to train a quantum network of pairwise interacting qubits such
that its evolution implements a target quantum algorithm into a given network
subset. Our strategy is inspired by supervised learning and is designed to help
the physical construction of a quantum computer which operates with minimal
external classical control.


title:
L-functions of Carlitz modules, resultantal varieties and rooted binary
  trees, II

abstract:
  We continue study of some algebraic varieties (called resultantal varieties)
started in a paper of A. Grishkov, D. Logachev "Resultantal varieties related
to zeroes of L-functions of Carlitz modules". These varieties are related with
the Sylvester matrix for the resultant of two polynomials, from one side, and
with the L-functions of twisted Carlitz modules, from another side.
Surprisingly, these varieties are described in terms of finite weighted rooted
binary trees. We give a (conjecturally) complete description of them, we find
parametrizations of their irreducible components and their invariants: degrees,
multiplicities, Jordan forms, Galois actions. Proof of the fact that this
description is really complete is a subject of future research. Maybe a
generalization of these results will give us a solution of the problem of
boundedness of the analytic rank of twists of Carlitz modules.


title: Product Theorem for K-stability

abstract: We study K-stability of products of K-stable $\mathbb{Q}$-Fano varieties.


title: Normal bundles of rational curves in projective space

abstract:
  Let $b_{\bullet}$ be a sequence of integers $1 < b_1 \leq b_2 \leq \cdots
\leq b_{n-1}$. Let $M(b_{\bullet})$ be the space parameterizing nondegenerate,
rational curves of degree $e$ in $\mathbb{P}^n$ with ordinary singularities
such that the normal bundle has the splitting type
$\bigoplus_{i=1}^{n-1}\mathcal{O}(e+b_i)$. When $n=3$, celebrated results of
Eisenbud, Van de Ven, Ghione and Sacchiero show that $M(b_{\bullet})$ is
irreducible of the expected dimension. We show that when $n \geq 5$, these loci
are generally reducible with components of higher than the expected dimension.
We give examples where the number of components grows linearly with $n$. These
generalize an example of Alzati and Re.


title:
Fine structure of moments of the KMK transform of the Poissonized
  Plancharel measure

abstract:
  We consider asymptotics behavior of Poissonized Plancharel measures as the
poissonization parameter $N$ goes to infinity. Recently Moll proved a
convergent series expansion for statistics of a measure $\mu_\lambda$ which is
the Kerov-Markov-Krein transform of the signed measure on corners a Jack-random
partition $\lambda$. The measure $\mu_\lambda$ is of interest because it
behaves in some ways like the empirical measure on eigenvalues of a GUE-random
matrix. We prove for the Poissonized Plancharel case that the large $N$ series
for moments of $\mu_\lambda$ have a recursive structure as rational expressions
in the generating function for Catalan numbers. We discuss the analogy between
our result and the fine structure of moments of the GUE.


title:
Fractional charge pumping of interacting bosons in one-dimensional
  superlattice

abstract:
  Motivated by experimental realizations of integer quantized charge pumping in
one-dimensional superlattices~[Nat. Phys. 12, 350 (2016); Nat. Phys. 12, 296
(2016)], we generalize and propose the adiabatic pumping of a fractionalized
charge in interacting bosonic systems. This is achieved by dynamically sweeping
the modulated potential in a class of one-dimensional interacting systems. As
concrete examples, we show the charge pumping of interacting bosons at certain
fractionally occupied fillings. We find that, for a given ground state, the
charge pumping in a complete potential cycle is quantized to the fractional
value related to the corresponding Chern number, characterized by the motion of
the charge polarization per site. Moreover, the difference between charge
polarizations of two ground states is quantized to an intrinsic constant
revealing the fractional elementary charge of quasiparticle.


title:
Physical parameter study of eight W Ursae Majoris-type contact binaries
  in NGC 188

abstract:
  We used the newly commissioned 50 cm Binocular Network (50BiN) telescope at
Qinghai Station of Purple Mountain Observatory (Chinese Academy of Sciences) to
observe the old open cluster NGC 188 in V and R as part of a search for
variable objects. Our time-series data span a total of 36 days. Radial velocity
and proper-motion selection resulted in a sample of 532 genuine cluster
members. Isochrone fitting was applied to the cleaned cluster sequence,
yielding a distance modulus of (m - M)0V = 11.35 \pm 0.10 mag and a total
foreground reddening of E(V - R) = 0.062 \pm 0.002 mag. Light-curve solutions
were obtained for eight W Ursae Majoris eclipsing-binary systems (W UMas) and
their orbital parameters were estimated. Using the latter parameters, we
estimate a distance to the W UMas which is independent of the host cluster's
physical properties. Based on combined fits to six of the W UMas (EP Cep, EQ
Cep, ES Cep, V369 Cep, and--for the first time--V370 Cep and V782 Cep), we
obtain an average distance modulus of (m - M)0V = 11.31 \pm 0.08 mag, which is
comparable with that resulting from our isochrone fits. These six W UMas
exhibit an obvious period-luminosity relation. We derive more accurate physical
parameters for the W UMa systems and discuss their initial masses and ages. The
former show that these W UMa systems have likely undergone angular-momentum
evolution within a convective envelope (W-type evolution). The ages of the W
UMa systems agree well with the cluster's age.


title:
Compositional Sequence Labeling Models for Error Detection in Learner
  Writing

abstract:
  In this paper, we present the first experiments using neural network models
for the task of error detection in learner writing. We perform a systematic
comparison of alternative compositional architectures and propose a framework
for error detection based on bidirectional LSTMs. Experiments on the CoNLL-14
shared task dataset show the model is able to outperform other participants on
detecting errors in learner writing. Finally, the model is integrated with a
publicly deployed self-assessment system, leading to performance comparable to
human annotators.


title: The evolution of the galaxy content of dark matter haloes

abstract:
  We use the halo occupation distribution (HOD) framework to characterise the
predictions from two independent galaxy formation models for the galactic
content of dark matter haloes and its evolution with redshift. Our galaxy
samples correspond to a range of fixed number densities defined by stellar mass
and span $0 \le z \le 3$. We find remarkable similarities between the model
predictions. Differences arise at low galaxy number densities which are
sensitive to the treatment of heating of the hot halo by active galactic
nuclei. The evolution of the form of the HOD can be described in a relatively
simple way, and we model each HOD parameter using its value at $z=0$ and an
additional evolutionary parameter. In particular, we find that the ratio
between the characteristic halo masses for hosting central and satellite
galaxies can serve as a sensitive diagnostic for galaxy evolution models. Our
results can be used to test and develop empirical studies of galaxy evolution
and can facilitate the construction of mock galaxy catalogues for future
surveys.


title: Gravitational dual of the R\'{e}nyi twist displacement operator

abstract:
  We give a recipe for computing correlation functions of the displacement
operator localized on a spherical or planar higher dimensional twist defect
using AdS/CFT. Such twist operators are typically used to construct the $n$'th
Renyi entropies of spatial entanglement in CFTs and are holographically dual to
black holes with hyperbolic horizons. The displacement operator then tells us
how the Renyi entropies change under small shape deformations of the entangling
surface. We explicitly construct the bulk to boundary propagator for the
displacement operator insertion as a linearized metric fluctuation of the
hyperbolic black hole and use this to extract the coefficient of the
displacement operator two point function $C_D$ in any dimension. The $n
\rightarrow 1$ limit of the twist displacement operator gives the same bulk
response as the insertion of a null energy operator in vacuum, which is
consistent with recent results on the shape dependence of entanglement entropy
and modular energy.


title: An Adaptive Parallel Algorithm for Computing Connected Components

abstract:
  We present an efficient distributed memory parallel algorithm for computing
connected components in undirected graphs based on Shiloach-Vishkin's PRAM
approach. We discuss multiple optimization techniques that reduce communication
volume as well as load-balance the algorithm. We also note that the efficiency
of the parallel graph connectivity algorithm depends on the underlying graph
topology. Particularly for short diameter graph components, we observe that
parallel Breadth First Search (BFS) method offers better performance. However,
running parallel BFS is not efficient for computing large diameter components
or large number of small components. To address this challenge, we employ a
heuristic that allows the algorithm to quickly predict the type of the network
by computing the degree distribution and follow the optimal hybrid route. Using
large graphs with diverse topologies from domains including metagenomics, web
crawl, social graph and road networks, we show that our hybrid implementation
is efficient and scalable for each of the graph types. Our approach achieves a
runtime of 215 seconds using 32K cores of Cray XC30 for a metagenomic graph
with over 50 billion edges. When compared against the previous state-of-the-art
method, we see performance improvements up to 24x.


title: Instanton Corrections of 1/6 BPS Wilson Loops in ABJM Theory

abstract:
  We study instanton corrections to the vacuum expectation value (VEV) of 1/6
BPS Wilson loops in ABJM theory from the Fermi gas approach. We mainly consider
Wilson loops in the fundamental representation and winding Wilson loops, but we
also initiate the study of Wilson loops with two boundaries. We find that the
membrane instanton corrections to the Wilson loop VEV are determined by the
refined topological string in the Nekrasov-Shatashvili limit, and the pole
cancellation mechanism between membrane instantons and worldsheet instantons
works also in the Wilson loop VEVs as in the case of the partition functions.


title:
Dimension Reduction in Statistical Estimation of Partially Observed
  Multiscale Processes

abstract:
  We consider partially observed multiscale diffusion models that are specified
up to an unknown vector parameter. We establish for a very general class of
test functions that the filter of the original model converges to a filter of
reduced dimension. Then, this result is used to justify statistical estimation
for the unknown parameters of interest based on the model of reduced dimension
but using the original available data. This allows to learn the unknown
parameters of interest while working in lower dimensions, as opposed to working
with the original high dimensional system. Simulation studies support and
illustrate the theoretical results.

categories: math.PR math.ST q-fin.ST stat.ME stat.TH


title:
On Kottler's path: origin and evolution of the premetric program in
  gravity and in electrodynamics

abstract:
  In 1922, Kottler put forward the program to remove the gravitational
potential, the metric of spacetime, from the fundamental equations in physics
as far as possible. He successfully applied this idea to Newton's
gravitostatics and to Maxwell's electrodynamics, where Kottler recast the field
equations in premetric form and specified a metric-dependent constitutive law.
We will discuss the basics of the premetric approach and some of its beautiful
consequences, like the division of universal constants into two classes. We
show that classical electrodynamics can be developed without a metric quite
straightforwardly: the Maxwell equations, together with a local and linear
response law for electromagnetic media, admit a consistent premetric
formulation. Kottler's program succeeds here without provisos. In Kottler's
approach to gravity, making the theory relativistic, two premetric
quasi-Maxwellian field equations arise, but their field variables, if
interpreted in terms of general relativity, do depend on the metric. However,
one can hope to bring the Kottler idea to work by using the teleparallelism
equivalent of general relativity, where the gravitational potential, the
coframe, can be chosen in a premetric way.


title: On the arbitrarily long-term stability of conservative methods

abstract:
  We show the arbitrarily long-term stability of conservative methods for
autonomous ODEs. Given a system of autonomous ODEs with conserved quantities,
if the preimage of the conserved quantities possesses a bounded locally nite
neighborhood, then the global error of any conservative method with the
uniformly bounded displacement property is bounded for all time, when the
uniform time step is taken suciently small. On nite precision machines, the
global error still remains bounded and independent of time until some
arbitrarily large time determined by machine precision and tolerance. The main
result is proved using elementary topological properties for discretized
conserved quantities which are equicontinuous. In particular, long-term
stability is also shown using an averaging identity when the discretized
conserved quantities do not explicitly depend on time steps. Numerical results
are presented to illustrate the long-term stability result.


title: Correspondences between convex geometry and complex geometry

abstract:
  We present several analogies between convex geometry and the theory of
holomorphic line bundles on smooth projective varieties or K\"ahler manifolds.
We study the relation between positive products and mixed volumes. We define
and study a Blaschke addition for divisor classes and mixed divisor classes,
and prove new geometric inequalities for divisor classes. We also reinterpret
several classical convex geometry results in the context of algebraic geometry:
the Alexandrov body construction is the convex geometry version of divisorial
Zariski decomposition; Minkowski's existence theorem is the convex geometry
version of the duality between the pseudo-effective cone of divisors and the
movable cone of curves.


title: Experimental and DFT investigation of (Cr,Ti)3AlC2 MAX phases stability

abstract:
  Using a synergistic combination of experimental and computational methods, we
shed light on the unusual solubility of (Cr,Ti)3AlC2 MAX phase, showing that it
may accommodate Cr only at very low concentrations (<2at%) or at the exact
Cr/(Cr+Ti) ratio of 2/3, even when the ratio of reactants is far from this
stoichiometry (1/2 < Cr/(Cr+Ti) < 5/6). In both phases Cr exclusively occupies
the 4f sites, bridging carbide layers with the Al layer. Despite this, the
peculiar stability of (Cr2/3Ti1/3)3AlC2 is attributed to the formation of
strong, spin-polarised Cr-C bonds, which result in volume reduction and marked
increase in c/a ratio.


title: Indirect Inference With(Out) Constraints

abstract:
  Indirect Inference (I-I) estimation of structural parameters $\theta$
{{requires matching observed and simulated statistics, which are most often
generated using an auxiliary model that depends on instrumental parameters
$\beta$.}} {The estimators of the instrumental parameters will encapsulate} the
statistical information used for inference about the structural parameters. As
such, artificially constraining these parameters may restrict the ability of
the auxiliary model to accurately replicate features in the structural data,
which may lead to a range of issues, such as, a loss of identification.
However, in certain situations the parameters $\beta$ naturally come with a set
of $q$ restrictions. Examples include settings where $\beta$ must be estimated
subject to $q$ possibly strict inequality constraints $g(\beta) > 0$, such as,
when I-I is based on GARCH auxiliary models. In these settings we propose a
novel I-I approach that uses appropriately modified unconstrained auxiliary
statistics, which are simple to compute and always exists. We state the
relevant asymptotic theory for this I-I approach without constraints and show
that it can be reinterpreted as a standard implementation of I-I through a
properly modified binding function. Several examples that have featured in the
literature illustrate our approach.


title:
Estimate the radius of the convective core of main-sequence stars from
  observed oscillation frequencies

abstract:
  The determination of the size of the convective core of main-sequence stars
is usually dependent on the construction of models of stars. Here we introduce
a method to estimate the radius of the convective core of main-sequence stars
with masses between about 1.1 and 1.5 $M_{\odot}$ from observed frequencies of
low-degree p-modes. A formula is proposed to achieve the estimation. The values
of the radius of the convective core of four known stars are successfully
estimated by the formula. The radius of the convective core of KIC 9812850
estimated by the formula is $\mathbf{0.140\pm0.028}$ $R_{\odot}$. In order to
confirm this prediction, a grid of evolutionary models were computed. The value
of the convective-core radius of the best-fit model of KIC 9812850 is $0.149$
$R_{\odot}$, which is in good agreement with that estimated by the formula from
observed frequencies. The formula aids in understanding the interior structure
of stars directly from observed frequencies. The understanding is not dependent
on the construction of models.


title: On $\mathbb{P}$-Weakly Hyperbolic Iterated Function Systems

abstract:
  In this paper we will consider the concept of $\mathbb{P}$-weakly hyperbolic
iterated function systems on compact metric spaces that generalizes the concept
of weakly hyperbolic iterated function systems, as defined by Edalat in
\cite{E} and by Arbieto, Santiago and Junqueira in \cite{ASJ} for a more
general setting where the parameter space is a compact metric space. We prove
the existence and uniqueness of the invariant measure of a $\mathbb{P}$-weakly
hyperbolic IFS. Furthermore, we prove an ergodic theorem for
$\mathbb{P}$-weakly hyperbolic IFS with compact parameter space.


title: Local Multiple Directional Pattern of Palmprint Image

abstract:
  Lines are the most essential and discriminative features of palmprint images,
which motivate researches to propose various line direction based methods for
palmprint recognition. Conventional methods usually capture the only one of the
most dominant direction of palmprint images. However, a number of points in
palmprint images have double or even more than two dominant directions because
of a plenty of crossing lines of palmprint images. In this paper, we propose a
local multiple directional pattern (LMDP) to effectively characterize the
multiple direction features of palmprint images. LMDP can not only exactly
denote the number and positions of dominant directions but also effectively
reflect the confidence of each dominant direction. Then, a simple and effective
coding scheme is designed to represent the LMDP and a block-wise LMDP
descriptor is used as the feature space of palmprint images in palmprint
recognition. Extensive experimental results demonstrate the superiority of the
LMDP over the conventional powerful descriptors and the state-of-the-art
direction based methods in palmprint recognition.


title:
Coarse-grained molecular dynamics simulation of binary charged lipid
  membranes: Phase separation and morphological dynamics

abstract:
  Biomembranes, which are mainly composed of neutral and charged lipids,
exhibit a large variety of functional structures and dynamics. Here, we report
a coarse-grained molecular dynamics (MD) simulation of the phase separation and
morphological dynamics in charged lipid bilayer vesicles. The screened
long-range electrostatic repulsion among charged head groups delays or inhibits
the lateral phase separation in charged vesicles compared with neutral
vesicles, suggesting the transition of the phase-separation mechanism from
spinodal decomposition to nucleation or homogeneous dispersion. Moreover, the
electrostatic repulsion causes morphological changes, such as pore formation,
and further transformations into disk, string, and bicelle structures, which
are spatiotemporally coupled to the lateral segregation of charged lipids.
Based on our coarse-grained MD simulation, we propose a plausible mechanism of
pore formation at the molecular level. The pore formation in a
charged-lipid-rich domain is initiated by the prior disturbance of the local
molecular orientation in the domain.


title: The fundamental advantages of temporal networks

abstract:
  Despite the traditional focus of network science on static networks, most
networked systems of scientific interest are characterized by temporal links.
By disrupting the paths, link temporality has been shown to frustrate many
dynamical processes on networks, from information spreading to accessibility.
Considering the ubiquity of temporal networks in nature, we must ask: Are there
any advantages of the networks' temporality? Here we develop an analytical
framework to explore the control properties of temporal networks, arriving at
the counterintuitive conclusion that temporal networks, compared to their
static (i.e. aggregated) counterparts, reach controllability faster, demand
orders of magnitude less control energy, and the control trajectories, through
which the system reaches its final states, are significantly more compact than
those characterizing their static counterparts. The combination of analytical,
numerical and empirical results demonstrates that temporality ensures a degree
of flexibility that would be unattainable in static networks, significantly
enhancing our ability to control them.


title:
$SU(1,1)$ solution for the Dunkl oscillator in two dimensions and its
  coherent states

abstract:
  We study the Dunkl oscillator in two dimensions by the $su(1,1)$ algebraic
method. We apply the Schr\"odinger factorization to the radial Hamiltonian of
the Dunkl oscillator to find the $su(1,1)$ Lie algebra generators. The energy
spectrum is found by using the theory of unitary irreducible representations.
By solving analytically the Schr\"odinger equation, we construct the Sturmian
basis for the unitary irreducible representations of the $su(1,1)$ Lie algebra.
We construct the $SU(1,1)$ Perelomov radial coherent states for this problem
and compute their time evolution.


title:
Fast and accurate generation method of PSF-based system matrix for PET
  reconstruction

abstract:
  Positional single photon incidence response (P-SPIR) theory is researched in
this paper to generate more accurate PSF-contained system matrix simply and
quickly. The method has been proved highly effective to improve the spatial
resolution by applying to the Eplus-260 primate PET designed by the Institute
of High Energy Physics of the Chinese Academy of Sciences(IHEP).
Simultaneously, to meet the clinical needs, GPU acceleration is put to use.
Basically, P-SPIR theory takes both incidence angle and incidence position by
crystal subdivision instead of only incidence angle into consideration based on
Geant4 Application for Emission Tomography (GATE). The simulation conforms to
the actual response distribution and can be completed rapidly within less than
1s. Furthermore,two-block penetration and normalization of the response
probability are raised to fit the reality. With PSF obtained, the
homogenization model is analyzed to calculate the spread distribution of bins
within a few minutes for system matrix generation. As a reult, The images
reconstructed indicate that the P-SPIR method can effectively inhibit the depth
of interaction (DOI) effect especially in the field close to the edge of the
field of view (FOV). What is more, the method can be promoted to any other PET
and the list-mode organization structure high-speedily and efficiently, which
substantially reduces the computing cost and ensures the accuracy of system
matrix for PET reconstruction.


title: Spin and the Coulomb Gap in the Half-Filled Lowest Landau Level

abstract:
  The Coulomb gap observed in tunneling between parallel two-dimensional
electron systems, each at half filling of the lowest Landau level, is found to
depend sensitively on the presence of an in-plane magnetic field. Especially at
low electron density, the width of the Coulomb gap at first increases sharply
with in-plane field, but then abruptly levels off. This behavior appears to
coincide with the known transition from partial to complete spin polarization
of the half-filled lowest Landau level. The tunneling gap therefore opens a new
window onto the spin configuration of two-dimensional electron systems at high
magnetic field.


title: The Primordial Inflation Polarization Explorer (PIPER)

abstract:
  The Primordial Inflation Polarization ExploreR (PIPER) is a balloon-borne
telescope designed to measure the polarization of the Cosmic Microwave
Background on large angular scales. PIPER will map 85% of the sky at 200, 270,
350, and 600 GHz over a series of 8 conventional balloon flights from the
northern and southern hemispheres. The first science flight will use two 32x40
arrays of backshort-under-grid transition edge sensors, multiplexed in the time
domain, and maintained at 100 mK by a Continuous Adiabatic Demagnetization
Refrigerator. Front-end cryogenic Variable-delay Polarization Modulators
provide systematic control by rotating linear to circular polarization at 3 Hz.
Twin telescopes allow PIPER to measure Stokes I, Q, U, and V simultaneously.
The telescope is maintained at 1.5 K in an LHe bucket dewar. Cold optics and
the lack of a warm window permit sensitivity at the sky-background limit. The
ultimate science target is a limit on the tensor-to-scalar ratio of r ~ 0.007,
from the reionization bump to l ~ 300. PIPER's first flight will be from the
Northern hemisphere, and overlap with the CLASS survey at lower frequencies. We
describe the current status of the PIPER instrument.


title:
An FPTAS for the Volume of a ${\cal V}$-polytope ---It is Hard to
  Compute The Volume of The Intersection of Two Cross-polytopes

abstract:
  Given an $n$-dimensional convex body by a membership oracle in general, it is
known that any polynomial-time deterministic algorithm cannot approximate its
volume within ratio $(n/\log n)^n$. There is a substantial progress on
randomized approximation such as Markov chain Monte Carlo for a
high-dimensional volume, and for many #P-hard problems, while some
deterministic approximation algorithms are recently developed only for a few
#P-hard problems. Motivated by a deterministic approximation of the volume of a
${\cal V}$-polytope, that is a polytope with few vertices and (possibly)
exponentially many facets, this paper investigates the volume of a "knapsack
dual polytope," which is known to be #P-hard due to Khachiyan (1989). We reduce
an approximate volume of a knapsack dual polytope to that of the intersection
of two cross-polytopes, and give FPTASs for those volume computations.
Interestingly, the volume of the intersection of two cross-polytopes (i.e.,
$L_1$-balls) is #P-hard, unlike the cases of $L_{\infty}$-balls or $L_2$-balls.


title: Six-dimensional regularization of chiral gauge theories

abstract:
  We propose a regularization of four dimensional chiral gauge theories using
six-dimensional Dirac fermions. In our formulation, we consider two different
mass terms having domain-wall profiles in the fifth and the sixth directions,
respectively. A Weyl fermion appears as a localized mode at the junction of two
different domain-walls. One domain-wall naturally exhibits the Stora-Zumino
chain of the anomaly descent equations, starting from the axial U(1) anomaly in
six-dimensions to the gauge anomaly in four-dimensions. Another domain-wall
implies a similar inflow of the global anomalies. The anomaly free condition is
equivalent to requiring that the axial U(1) anomaly and the parity anomaly are
canceled among the six-dimensional Dirac fermions. Since our formulation is
based on a massive vector-like fermion determinant, a non-perturbative
regularization will be possible on a lattice. Putting the gauge field at the
four-dimensional junction and extending it to the bulk using the Yang-Mills
gradient flow, as recently proposed by Grabowska and Kaplan, we define the
four-dimensional path integral of the target chiral gauge theory.


title: Peculiarity of the oscillation stratification in sunspot penumbrae

abstract:
  Spatial distributions of the dominant oscillation frequency obtained for four
sunspots show a feature shared by all the analysed levels of the solar
atmosphere in these sunspots. This feature located in the inner penumbrae
indicates that this region has favourable conditions for 2.5-4 mHz oscillation
propagation. This agrees with the fact that the spectral composition of the
oscillations at three atmospheric heights (FeI 6173{\AA}, 1700{\AA}, and He II
304{\AA}) in this region are similar. There have been previous evidence of
particular similarities along height of photospheric magnetic field strength,
line-of-sight velocity, and temperature profile in the inner penumbra, where
the internal boundary of the Evershed flow is located. The finding of the same
dominant oscillation frequency at a range of altitudes from the chromosphere up
to the transition region extends the height range, suggesting similarities in
physical conditions.


title: Energy and Laplacian of Fractal Interpolation Functions

abstract:
  In this paper, we first characterize the finiteness of fractal interpolation
functions (FIFs) on post critical finite self-similar sets. Then we study the
Laplacian of FIFs with uniform vertical scaling factors on Sierpinski gasket
(SG). As an application, we prove that the solution of the following Dirichlet
problem on SG is an FIF with uniform vertical scaling factor $\frac{1}{5}$:
$\Delta u=0$ on $SG\setminus \{q_1,q_2,q_3\}$, and $u(q_i)=a_i$, $i=1,2,3$,
where $q_i$, $i=1,2,3$, are boundary points of SG.


title: Concentration and limit behaviors of stationary measures

abstract:
  In this paper, we study limit behaviors of stationary measures of the
Fokker-Planck equations associated with a system of ordinary differential
equations perturbed by a class of multiplicative including additive white
noises. As the noises are vanishing, various results on the invariance and
concentration of the limit measures are obtained. In particular, we show that
if the noise perturbed systems admit a uniform Lyapunov function, then the
stationary measures form a relatively sequentially compact set whose
weak$^*$-limits are invariant measures of the unperturbed system concentrated
on its global attractor. In the case that the global attractor contains a
strong local attractor, we further show that there exists a family of
admissible multiplicative noises with respect to which all limit measures are
actually concentrated on the local attractor; and on the contrary, in the
presence of a strong local repeller in the global attractor, there exists a
family of admissible multiplicative noises with respect to which no limit
measure can be concentrated on the local repeller. Moreover, we show that if
there is a strongly repelling equilibrium in the global attractor, then limit
measures with respect to typical families of multiplicative noises are always
concentrated away from the equilibrium. As applications of these results, an
example of stochastic Hopf bifurcation is provided.
  Our study is closely related to the problem of noise stability of compact
invariant sets and invariant measures of the unperturbed system.


title: Feature Descriptors for Tracking by Detection: a Benchmark

abstract:
  In this paper, we provide an extensive evaluation of the performance of local
descriptors for tracking applications. Many different descriptors have been
proposed in the literature for a wide range of application in computer vision
such as object recognition and 3D reconstruction. More recently, due to fast
key-point detectors, local image features can be used in online tracking
frameworks. However, while much effort has been spent on evaluating their
performance in terms of distinctiveness and robustness to image
transformations, very little has been done in the contest of tracking. Our
evaluation is performed in terms of distinctiveness, tracking precision and
tracking speed. Our results show that binary descriptors like ORB or BRISK have
comparable results to SIFT or AKAZE due to a higher number of key-points.


title: Hybrid LSH: Faster Near Neighbors Reporting in High-dimensional Space

abstract:
  We study the $r$-near neighbors reporting problem ($r$-NN), i.e., reporting
\emph{all} points in a high-dimensional point set $S$ that lie within a radius
$r$ of a given query point $q$. Our approach builds upon on the
locality-sensitive hashing (LSH) framework due to its appealing asymptotic
sublinear query time for near neighbor search problems in high-dimensional
space. A bottleneck of the traditional LSH scheme for solving $r$-NN is that
its performance is sensitive to data and query-dependent parameters. On
datasets whose data distributions have diverse local density patterns, LSH with
inappropriate tuning parameters can sometimes be outperformed by a simple
linear search.
  In this paper, we introduce a hybrid search strategy between LSH-based search
and linear search for $r$-NN in high-dimensional space. By integrating an
auxiliary data structure into LSH hash tables, we can efficiently estimate the
computational cost of LSH-based search for a given query regardless of the data
distribution. This means that we are able to choose the appropriate search
strategy between LSH-based search and linear search to achieve better
performance. Moreover, the integrated data structure is time efficient and fits
well with many recent state-of-the-art LSH-based approaches. Our experiments on
real-world datasets show that the hybrid search approach outperforms (or is
comparable to) both LSH-based search and linear search for a wide range of
search radii and data distributions in high-dimensional space.


title:
Collisional stability of localized Yb(${}^3\mathrm{P}_2$) atoms immersed
  in a Fermi sea of Li

abstract:
  We establish an experimental method for a detailed investigation of inelastic
collisional properties between ytterbium (Yb) in the metastable
${}^3\mathrm{P}_2$ state and ground state lithium (Li). By combining an optical
lattice and a direct excitation to the ${}^3\mathrm{P}_2$ state we achieve high
selectivity on the collisional partners. Using this method we determine
inelastic loss coefficients in collisions between
$^{174}$Yb(${}^3\mathrm{P}_2$) with magnetic sublevels of $m_J=0$ and $-2$ and
ground state $^6$Li to be $(4.4\pm0.3)\times10^{-11}~\mathrm{cm}^3/\mathrm{s}$
and $(4.7\pm0.8)\times10^{-11}~\mathrm{cm}^3/\mathrm{s}$, respectively. Absence
of spin changing processes in Yb(${}^3\mathrm{P}_2$)-Li inelastic collisions at
low magnetic fields is confirmed by inelastic loss measurements on the $m_J=0$
state. We also demonstrate that our method allows us to look into loss
processes in few-body systems separately.


title:
Quantum crystallography of Rydberg-dressed Bose gases on a square
  lattice

abstract:
  We numerically investigate the quantum crystallographic phases of a
Rydberg-dressed Bose gas loaded on a square lattice by using the mean-field
Gross--Pitaevskii model. For a relatively weak lattice confinement, the phases
of ground state undergo amorphism, polycrystal, and polymorphism following the
increase of the blockade radius, and if the confinement is stronger, a single
crystal with a specific filling factor will be formed. In order to
distinctively characterize these phases, the structure function is also
studied. In such an anisotropic system, we report that the first diagonal
element of the superfluid-fraction tensor should be a measurable quantity, and
an anisotropy parameter can be defined. In addition, for such crystallographic
phases, the interaction potential can manifest where the grain boundaries
appear.


title: Streaming Recommender Systems

abstract:
  The increasing popularity of real-world recommender systems produces data
continuously and rapidly, and it becomes more realistic to study recommender
systems under streaming scenarios. Data streams present distinct properties
such as temporally ordered, continuous and high-velocity, which poses
tremendous challenges to traditional recommender systems. In this paper, we
investigate the problem of recommendation with stream inputs. In particular, we
provide a principled framework termed sRec, which provides explicit
continuous-time random process models of the creation of users and topics, and
of the evolution of their interests. A variational Bayesian approach called
recursive meanfield approximation is proposed, which permits computationally
efficient instantaneous on-line inference. Experimental results on several
real-world datasets demonstrate the advantages of our sRec over other
state-of-the-arts.


title: Natural selection in the colloid world: Active chiral spirals

abstract:
  We present a model system in which to study natural selection in the colloid
world. In the assembly of active Janus particles into rotating pinwheels when
mixed with trace amounts of homogeneous colloids in the presence of an AC
electric field, broken symmetry in the rotation direction produces spiral,
chiral shapes. Locked into a central rotation point by the center particle, the
spiral arms are found to trail rotation of the overall cluster. To achieve a
steady state, the spiral arms undergo an evolutionary process to coordinate
their motion. Because all the particles as segments of the pinwheel arms are
self-propelled, asymmetric arm lengths are tolerated. Reconfiguration of these
structures can happen in various ways and various mechanisms of this directed
structural change are analyzed in detail. We introduce the concept of VIP (very
important particles) to express that sustainability of active structures is
most sensitive to only a few particles at strategic locations in the moving
self-assembled structures.


title:
Derivation of a time dependent Schr\"odinger equation as quantum
  mechanical Landau-Lifshitz-Bloch equation

abstract:
  The derivation of the time dependent Schr\"odinger equation with transversal
and longitudinal relaxation, as the quantum mechanical analog of the classical
Landau-Lifshitz-Bloch equation, has been described. Starting from the classical
Landau-Lifshitz-Bloch equation the transition to quantum mechanics has been
performed and the corresponding von-Neumann equation deduced. In a second step
the time Schr\"odinger equation has been derived. Analytical proofs and
computer simulations show the correctness and applicability of the derived
Schr\"odinger equation.


title:
Thermodynamic stability of modified Schwarzschild-AdS black hole in
  rainbow gravity

abstract:
  In this paper, we have extended the previous study of the thermodynamics and
phase transition of the Schwarzschild black hole in the rainbow gravity to the
Schwarzschild-AdS black hole where metric depends on the energy of a probe.
Making use of the Heisenberg uncertainty principle and the modified dispersion
relation, we have obtained the modified local Hawking temperature and
thermodynamic quantities in an isothermal cavity. Moreover, we carry out the
analysis of constant temperature slices of a black hole. As a result, we have
shown that there also exists another Hawking-Page-like phase transition in
which case a locally stable small black hole tunnels into a globally stable
large black hole as well as the standard Hawking-Page phase transition from a
hot flat space to a black hole.


title:
Applying Interval Type-2 Fuzzy Rule Based Classifiers Through a
  Cluster-Based Class Representation

abstract:
  Fuzzy Rule-Based Classification Systems (FRBCSs) have the potential to
provide so-called interpretable classifiers, i.e. classifiers which can be
introspective, understood, validated and augmented by human experts by relying
on fuzzy-set based rules. This paper builds on prior work for interval type-2
fuzzy set based FRBCs where the fuzzy sets and rules of the classifier are
generated using an initial clustering stage. By introducing Subtractive
Clustering in order to identify multiple cluster prototypes, the proposed
approach has the potential to deliver improved classification performance while
maintaining good interpretability, i.e. without resulting in an excessive
number of rules. The paper provides a detailed overview of the proposed FRBC
framework, followed by a series of exploratory experiments on both linearly and
non-linearly separable datasets, comparing results to existing rule-based and
SVM approaches. Overall, initial results indicate that the approach enables
comparable classification performance to non rule-based classifiers such as
SVM, while often achieving this with a very small number of rules.


title:
Exploring Differences in Interpretation of Words Essential in Medical
  Expert-Patient Communication

abstract:
  In the context of cancer treatment and surgery, quality of life assessment is
a crucial part of determining treatment success and viability. In order to
assess it, patients completed questionnaires which employ words to capture
aspects of patients well-being are the norm. As the results of these
questionnaires are often used to assess patient progress and to determine
future treatment options, it is important to establish that the words used are
interpreted in the same way by both patients and medical professionals. In this
paper, we capture and model patients perceptions and associated uncertainty
about the words used to describe the level of their physical function used in
the highly common (in Sarcoma Services) Toronto Extremity Salvage Score (TESS)
questionnaire. The paper provides detail about the interval-valued data capture
as well as the subsequent modelling of the data using fuzzy sets. Based on an
initial sample of participants, we use Jaccard similarity on the resulting
words models to show that there may be considerable differences in the
interpretation of commonly used questionnaire terms, thus presenting a very
real risk of miscommunication between patients and medical professionals as
well as within the group of medical professionals.


title: Timescales in heavy ion collisions

abstract:
  The study of high energy collisions between heavy nuclei is a field unto
itself, distinct from nuclear and particle physics. A defining aspect of heavy
ion physics is the importance of a bulk, self-interacting system with a rich
space-time substructure. I focus on the issue of timescales in heavy ion
collisions, starting with proof from low-energy collisions that femtoscopy can,
indeed, measure very long timescales. I then discuss the relativistic case,
where detailed measurements over three orders of magnitude in energy reveal a
timescale increase that might be due to a first-order phase transition. I
discuss also consistency in evolution timescales as determined from traditional
longitudinal sizes and a novel analysis using shape information.


title: Syzygies of Cohen-Macaulay modules and Grothendieck groups

abstract:
  We study the converse of a theorem of Butler and Auslander-Reiten. We show
that a Cohen-Macaulay local ring with an isolated singularity has only finitely
many isomorphism classes of indecomposable summands of syzygies of
Cohen-Macaulay modules if the Auslander-Reiten sequences generate the relation
of the Grothendieck group of finitely generated modules. This extends a recent
result of Hiramatsu, which gives an affirmative answer in the Gorenstein case
to a conjecture of Auslander.


title:
An ensemble of machine learning and anti-learning methods for predicting
  tumour patient survival rates

abstract:
  This paper primarily addresses a dataset relating to cellular, chemical and
physical conditions of patients gathered at the time they are operated upon to
remove colorectal tumours. This data provides a unique insight into the
biochemical and immunological status of patients at the point of tumour removal
along with information about tumour classification and post-operative survival.
The relationship between severity of tumour, based on TNM staging, and survival
is still unclear for patients with TNM stage 2 and 3 tumours. We ask whether it
is possible to predict survival rate more accurately using a selection of
machine learning techniques applied to subsets of data to gain a deeper
understanding of the relationships between a patient's biochemical markers and
survival. We use a range of feature selection and single classification
techniques to predict the 5 year survival rate of TNM stage 2 and 3 patients
which initially produces less than ideal results. The performance of each model
individually is then compared with subsets of the data where agreement is
reached for multiple models. This novel method of selective ensembling
demonstrates that significant improvements in model accuracy on an unseen test
set can be achieved for patients where agreement between models is achieved.
Finally we point at a possible method to identify whether a patients prognosis
can be accurately predicted or not.


title:
Development of wide-field low-energy X-ray imaging detectors for
  HiZ-GUNDAM

abstract:
  We are planning a future gamma-ray burst (GRB) mission HiZ-GUNDAM to probe
the early universe beyond the redshift of z > 7. Now we are developing a small
prototype model of wide-field low-energy X-ray imaging detectors to observe
high-z GRBs, which cover the energy range of 1 - 20 keV. In this paper, we
report overview of its prototype system and performance, especially focusing on
the characteristics and radiation tolerance of high gain analog ASIC
specifically designed to read out small charge signals.


title:
Observation of Interaction of Spin and Intrinsic Orbital Angular
  Momentum of Light

abstract:
  Interaction of spin and intrinsic orbital angular momentum of light is
observed, as evidenced by length-dependent rotations of both spatial patterns
and optical polarization in a cylindrically-symmetric isotropic optical fiber.
Such rotations occur in straight few-mode fiber when superpositions of two
modes with parallel and anti-parallel orientation of spin and intrinsic orbital
angular momentum (IOAM=$2\hslash$) are excited, resulting from a degeneracy
splitting of the propagation constants of the modes.


title: First-principles DFT + GW study of the Te antisite in CdTe

abstract:
  Formation energies, charge transitions levels, and quasiparticle defect
states of the tellurium antisite $(\text{Te}_\text{Cd})$ in CdTe are addressed
within the DFT${0.05cm}+{0.05cm}$\emph{GW} formalism. We find that
$(\text{Te}_\text{Cd})$ induces a (+2/0) deep level at 0.99 eV above the
valence band maximum, exhibiting a negative-U effect. Moreover, the calculated
zero-phonon line for the excited state of $(\text{Te}_\text{Cd})^0$ corresponds
closely with the $\sim$1.1 eV band, visible in luminescence and absorption
experiments. Our results differ from previous theoretical studies, mainly due
to the well-known band gap error and the incorrect position of the band edges
predicted by standard DFT calculations.


title:
An information theory based search for homogeneity on the largest
  accessible scale

abstract:
  We analyze the SDSS DR12 quasar catalogue to test the large-scale smoothness
in the quasar distribution. We quantify the degree of inhomogeneity in the
quasar distribution using information theory based measures and find that the
degree of inhomogeneity diminishes with increasing length scales which finally
reach a plateau at $\sim 250 \, h^{-1}\, {\rm Mpc}$. The residual inhomogeneity
at the plateau is consistent with that expected for a Poisson point process.
Our results indicate that the quasar distribution is homogeneous beyond length
scales of $250 \, h^{-1}\, {\rm Mpc}$.


title:
Repetitive Patterns in Rapid Optical Variations in the Nearby Black-hole
  Binary V404 Cygni

abstract:
  How black holes accrete surrounding matter is a fundamental, yet unsolved
question in astrophysics. It is generally believed that matter is absorbed into
black holes via accretion disks, the state of which depends primarily on the
mass-accretion rate. When this rate approaches the critical rate (the Eddington
limit), thermal instability is supposed to occur in the inner disc, causing
repetitive patterns of large-amplitude X-ray variability (oscillations) on
timescales of minutes to hours. In fact, such oscillations have been observed
only in sources with a high mass accretion rate, such as GRS 1915+105. These
large-amplitude, relatively slow timescale, phenomena are thought to have
physical origins distinct from X-ray or optical variations with small
amplitudes and fast ($\lesssim$10 sec) timescales often observed in other black
hole binaries (e.g., XTE J1118+480 and GX 339-4). Here we report an extensive
multi-colour optical photometric data set of V404 Cygni, an X-ray transient
source containing a black hole of nine solar masses (and a conpanion star) at a
distance of 2.4 kiloparsecs. Our data show that optical oscillations on
timescales of 100 seconds to 2.5 hours can occur at mass-accretion rates more
than ten times lower than previously thought. This suggests that the accretion
rate is not the critical parameter for inducing inner-disc instabilities.
Instead, we propose that a long orbital period is a key condition for these
large-amplitude oscillations, because the outer part of the large disc in
binaries with long orbital periods will have surface densities too low to
maintain sustained mass accretion to the inner part of the disc. The lack of
sustained accretion -- not the actual rate -- would then be the critical factor
causing large-amplitude oscillations in long-period systems.


title: Report from the Open Problems Session at OPSFA13

abstract:
  These are the open problems presented at the 13th International Symposium on
Orthogonal Polynomials, Special Functions and Applications (OPSFA13),
Gaithersburg, Maryland, on June 4, 2015.

categories: math.CA math-ph math.CO math.MP math.NT math.PR


title: A holographic model for the baryon octet

abstract:
  By adopting the nonlinear realization of chiral symmetry, a holographic model
for the baryon octet is proposed. The mass spectra of the baryon octet and
their low-lying excited states are calculated, which show good consistency with
experiments. The couplings of pion to nucleons are derived in two gauges and
are shown to be equivalent with each other. It also shows that only derivative
couplings of pion to nucleons appear in this holographic model. The coupling
constant is then calculated.


title:
Supervised Adverse Drug Reaction Signalling Framework Imitating Bradford
  Hill's Causality Considerations

abstract:
  Big longitudinal observational medical data potentially hold a wealth of
information and have been recognised as potential sources for gaining new drug
safety knowledge. Unfortunately there are many complexities and underlying
issues when analysing longitudinal observational data. Due to these
complexities, existing methods for large-scale detection of negative side
effects using observational data all tend to have issues distinguishing between
association and causality. New methods that can better discriminate causal and
non-causal relationships need to be developed to fully utilise the data. In
this paper we propose using a set of causality considerations developed by the
epidemiologist Bradford Hill as a basis for engineering features that enable
the application of supervised learning for the problem of detecting negative
side effects. The Bradford Hill considerations look at various perspectives of
a drug and outcome relationship to determine whether it shows causal traits. We
taught a classifier to find patterns within these perspectives and it learned
to discriminate between association and causality. The novelty of this research
is the combination of supervised learning and Bradford Hill's causality
considerations to automate the Bradford Hill's causality assessment. We
evaluated the framework on a drug safety gold standard know as the
observational medical outcomes partnership's nonspecified association reference
set. The methodology obtained excellent discriminate ability with area under
the curves ranging between 0.792-0.940 (existing method optimal: 0.73) and a
mean average precision of 0.640 (existing method optimal: 0.141). The proposed
features can be calculated efficiently and be readily updated, making the
framework suitable for big observational data.


title:
First-principles prediction of mechanical and bonding characteristics of
  new T2 superconductor Ta5GeB2

abstract:
  In the present paper, DFT (Density Functional Theory) based first-principles
methods are applied to investigate the mechanical and bonding properties of
newly synthesized T2 phase superconductor Ta5GeB2 for the first time. The
calculated lattice constants are in reasonable agreement with the experiment.
The elastic constants (Cij), bulk modulus (B), shear modulus (G), Young's
modulus (Y), Poisson ratio (nu), Pugh ratio (G/B), and elastic anisotropy
factor, A, of Ta5GeB2 are calculated to explore the mechanical behavior of the
compound.To give an explanation of the bonding nature of this new ternary
tetragonal system, the band structure, density of states, and Mulliken atomic
population are investigated. The estimated Debye temperature and Vickers
hardness are also used to justify both the mechanical and bonding properties of
Ta5GeB2.


title:
Ferrimagnetism in delta chain with anisotropic ferromagnetic and
  antiferromagnetic interactions

abstract:
  We consider analytically and numerically an anisotropic spin-$\frac{1}{2}$
delta-chain (sawtooth chain) in which exchange interactions between apical and
basal spins are ferromagnetic and those between basal spins are
antiferromagnetic. In the limit of strong anisotropy of exchange interactions
this model can be considered as the Ising delta chain with macroscopic
degenerate ground state perturbed by transverse quantum fluctuations. These
perturbations lift the ground state degeneracy and the model reduces to the
basal XXZ spin chain in the magnetic field induced by static apical spins. We
show that the ground state of such model is ferrimagnetic. The excitations of
the model are formed by ferrimagnetic domains separated by domain walls with a
finite energy. At low temperatures the system is effectively divided into two
independent subsystems, the apical subsystem described by the Ising
spin-$\frac{1}{2}$ chain and the basal subsystem described by the XXZ chain
with infinite $zz$ interactions.


title: Faster Graph Coloring in Polynomial Space

abstract:
  We present a polynomial-space algorithm that computes the number independent
sets of any input graph in time $O(1.1387^n)$ for graphs with maximum degree 3
and in time $O(1.2355^n)$ for general graphs, where n is the number of
vertices. Together with the inclusion-exclusion approach of Bj\"orklund,
Husfeldt, and Koivisto [SIAM J. Comput. 2009], this leads to a faster
polynomial-space algorithm for the graph coloring problem with running time
$O(2.2355^n)$. As a byproduct, we also obtain an exponential-space
$O(1.2330^n)$ time algorithm for counting independent sets. Our main algorithm
counts independent sets in graphs with maximum degree 3 and no vertex with
three neighbors of degree 3. This polynomial-space algorithm is analyzed using
the recently introduced Separate, Measure and Conquer approach [Gaspers &
Sorkin, ICALP 2015]. Using Wahlstr\"om's compound measure approach, this
improvement in running time for small degree graphs is then bootstrapped to
larger degrees, giving the improvement for general graphs. Combining both
approaches leads to some inflexibility in choosing vertices to branch on for
the small-degree cases, which we counter by structural graph properties.


title: Body-centered phase of shock loaded Cu

abstract:
  Single crystal Cu when shock loaded in certain direction for a certain narrow
range of piston velocities undergoes a structural phase transition from
face-centered cubic to different body-centered phases. Based on molecular
dynamic simulations, the manuscript identifies new phases of Cu through
detailed radial distribution function and x-ray diffraction analysis.
Identification of the new phases of Cu should initiate a re-evaluation of phase
diagram for Cu under high temperature and pressure conditions.


title: Greedy bi-criteria approximations for $k$-medians and $k$-means

abstract:
  This paper investigates the following natural greedy procedure for clustering
in the bi-criterion setting: iteratively grow a set of centers, in each round
adding the center from a candidate set that maximally decreases clustering
cost. In the case of $k$-medians and $k$-means, the key results are as follows.
  $\bullet$ When the method considers all data points as candidate centers,
then selecting $\mathcal{O}(k\log(1/\varepsilon))$ centers achieves cost at
most $2+\varepsilon$ times the optimal cost with $k$ centers.
  $\bullet$ Alternatively, the same guarantees hold if each round samples
$\mathcal{O}(k/\varepsilon^5)$ candidate centers proportionally to their
cluster cost (as with $\texttt{kmeans++}$, but holding centers fixed).
  $\bullet$ In the case of $k$-means, considering an augmented set of
$n^{\lceil1/\varepsilon\rceil}$ candidate centers gives $1+\varepsilon$
approximation with $\mathcal{O}(k\log(1/\varepsilon))$ centers, the entire
algorithm taking
$\mathcal{O}(dk\log(1/\varepsilon)n^{1+\lceil1/\varepsilon\rceil})$ time, where
$n$ is the number of data points in $\mathbb{R}^d$.
  $\bullet$ In the case of Euclidean $k$-medians, generating a candidate set
via $n^{\mathcal{O}(1/\varepsilon^2)}$ executions of stochastic gradient
descent with adaptively determined constraint sets will once again give
approximation $1+\varepsilon$ with $\mathcal{O}(k\log(1/\varepsilon))$ centers
in $dk\log(1/\varepsilon)n^{\mathcal{O}(1/\varepsilon^2)}$ time.
  Ancillary results include: guarantees for cluster costs based on powers of
metrics; a brief, favorable empirical evaluation against $\texttt{kmeans++}$;
data-dependent bounds allowing $1+\varepsilon$ in the first two bullets above,
for example with $k$-medians over finite metric spaces.


title:
Modeling the Biophysical Effects in a Carbon Beam Delivery Line using
  Monte Carlo Simulation

abstract:
  Relative biological effectiveness (RBE) plays an important role in designing
a uniform dose response for ion beam therapy. In this study the biological
effectiveness of a carbon ion beam delivery system was investigated using Monte
Carlo simulation. A carbon ion beam delivery line was designed for the Korea
Heavy Ion Medical Accelerator (KHIMA) project. The GEANT4 simulation tool kit
was used to simulate carbon beam transporting into media. An incident energy
carbon ion beam in the range between 220 MeV/u and 290 MeV/u was chosen to
generate secondary particles. The microdosimetric-kinetic (MK) model is applied
to describe the RBE of 10% survival in human salivary gland (HSG) cells. The
RBE weighted dose was estimated as a function of the penetrating depth of the
water phantom along the incident beam direction. A biologically
photon-equivalent Spread Out Bragg Peak (SOBP) was designed using the RBE
weighted absorbed dose. Finally, the RBE of mixed beams was predicted as a
function of the water phantom depth.


title:
Finite-temperature crossover phenomenon in the $S=1/2$ antiferromagnetic
  Heisenberg model on the kagome lattice

abstract:
  Thermal properties of the $S=1/2$ kagome Heisenberg antiferromagnet at low
temperatures are investigated by means of the Hams-de Raedt method for clusters
of up to 36 sites possessing a full symmetry of the lattice. The specific heat
exhibits, in addition to the double peaks, the third and the forth peaks at
lower temperatures. With decreasing the temperature, the type of the magnetic
short-range order (SRO) changes around the third-peak temperature from the
$\sqrt{3} \times \sqrt{3}$ to the $q$=0 states, suggesting that the third peak
of the specific heat is associated with a crossover phenomenon between the
spin-liquid states with distinct magnetic SRO. Experimental implications are
discussed.


title: Development of a low-energy, high-brightness $\mu^+$ beam line

abstract:
  We are developing a beam line which compresses the phase space of a standard
surface $\mu^+$ beam by 10 orders of magnitude with an efficiency of $10^{-3}$.
Phase space compression occurs in a He gas target and consists of three
consecutive stages: Transverse (perpendicular to the beam axis) compression,
longitudinal compression and re-extraction into vacuum. Transverse compression
was observed for the first time and longitudinal compression has been measured
to occur within 2.5 $\mu$s with high efficiency.


title:
Restoring Interlayer Josephson Coupling in La_{1.885}Ba_{0.115}CuO_4 by
  Charge Transfer Melting of Stripe Order

abstract:
  We show that disruption of charge-density-wave (stripe) order by charge
transfer excitation, enhances the superconducting phase rigidity in
La_{1.885}Ba_{0.115}CuO_4 (LBCO). Time-Resolved Resonant Soft X-Ray Diffraction
demonstrates that charge order melting is prompt following near-infrared
photoexcitation whereas the crystal structure remains intact for moderate
fluences. THz time-domain spectroscopy reveals that, for the first 2 ps
following photoexcitation, a new Josephson Plasma Resonance edge, at higher
frequency with respect to the equilibrium edge, is induced indicating enhanced
superconducting interlayer coupling. The fluence dependence of the charge-order
melting and the enhanced superconducting interlayer coupling are correlated
with a saturation limit of about 0.5 mJ/cm2. Using a combination of x-ray and
optical spectroscopies we establish a hierarchy of timescales between enhanced
superconductivity, melting of charge order and rearrangement of the crystal
structure.


title: Exploring phrase-compositionality in skip-gram models

abstract:
  In this paper, we introduce a variation of the skip-gram model which jointly
learns distributed word vector representations and their way of composing to
form phrase embeddings. In particular, we propose a learning procedure that
incorporates a phrase-compositionality function which can capture how we want
to compose phrases vectors from their component word vectors. Our experiments
show improvement in word and phrase similarity tasks as well as syntactic tasks
like dependency parsing using the proposed joint models.


title: Microscopic effective reaction theory for deuteron-induced reactions

abstract:
  The microscopic effective reaction theory is applied to deuteron-induced
reactions. A reaction model-space characterized by a $p+n+{\rm A}$ three-body
model is adopted, where A is the target nucleus, and the nucleon-target
potential is described by a microscopic folding model based on an effective
nucleon-nucleon interaction in nuclear medium and a one-body nuclear density of
A. The three-body scattering wave function in the model space is obtained with
the continuum-discretized coupled-channels method (CDCC), and the eikonal
reaction theory (ERT), an extension of CDCC, is applied to the calculation of
neutron removal cross sections. Elastic scattering cross sections of deuteron
on $^{58}$Ni and $^{208}$Pb target nuclei at several energies are compared with
experimental data. The total reaction cross sections and the neutron removal
cross sections at 56 MeV on 14 target nuclei are calculated and compared with
experimental values.


title: Irreversibility of the two-dimensional enstrophy cascade

abstract:
  We study the time irreversibility of the direct cascade in two-dimensional
turbulence by looking at the time derivative of the square vorticity along
Lagrangian trajectories, a quantity which we call metenstrophy. By means of
extensive numerical simulations we measure the time irreversibility from the
asymmetry of the PDF of the metenstrophy and we find that it increases with the
Reynolds number of the cascade, similarly to what found in three-dimensional
turbulence. A detailed analysis of the different contributions to the enstrophy
budget reveals a remarkable difference with respect to what observed for the
direct cascade, in particular the role of the statistics of the forcing to
determine the degree of irreversibility.


title:
Sharpness of the phase transition and lower bounds for the critical
  intensity in continuum percolation on $\mathbb{R}^d$

abstract:
  We consider the Boolean model $Z$ on $\mathbb{R}^d$ with random compact
grains, i.e. $Z := \bigcup_{i \in \mathbb{N}} (X_i + Z_i)$ where $\eta_t :=
\{X_1, X_2, \dots\}$ is a Poisson point process of intensity $t$ and $(Z_1,
Z_2, \dots)$ is an i.i.d. sequence of compact grains (not necessarily balls).
We will show, that the volume and diameter of the cluster of a typical grain in
$Z$ have an exponential tail if the diameter of the typical grain is a.s.
bounded by some constant. To achieve this we adapt the arguments of
\cite{duminil2015newproof} and apply a new construction of the cluster of the
typical grain together with arguments related to branching processes. In the
second part of the paper, we obtain new lower bounds for the boolean model with
deterministic grains. Some of these bounds are rigorous, while others are
obtained via simulation. The simulated bounds are very close to the "true"
values and come with confidence intervals.


title: Spin wave and spin flip in hexagonal LuMnO3 single crystal

abstract:
  Manipulate and control of spin wave and spin flip are crucial for future
developments of magnonic and spintronic devices. We present that the spin wave
in hexagonal LuMnO3 single crystal can be selectively excited with laser
polarization perpendicular to the c-axis of hexagonal LuMnO3 and photon energy
~ 1.8 eV. The selective excitation of spin wave also suggests that the spin
flip can be selectively controlled in hexagonal manganites. In addition, the
physical origin of spin wave correlated with spin flip in hexagonal manganites
is discussed.


title: Generic absoluteness and boolean names for elements of a Polish space

abstract:
  It is common knowledge in the set theory community that there exists a
duality relating the commutative $C^*$-algebras with the family of $B$-names
for complex numbers in a boolean valued model for set theory $V^B$. Several
aspects of this correlation have been considered in works of the late $1970$'s
and early $1980$'s, for example by Takeuti, and by Jech. Generalizing Jech's
results, we extend this duality so as to be able to describe the family of
boolean names for elements of any given Polish space $Y$ (such as the complex
numbers) in a boolean valued model for set theory $V^B$ as a space $C^+(X,Y)$
consisting of functions $f$ whose domain $X$ is the Stone space of $B$, and
whose range is contained in $Y$ modulo a meager set. We also outline how this
duality can be combined with generic absoluteness results in order to analyze,
by means of forcing arguments, the theory of $C^+(X,Y)$.


title:
Translation-Invariant Estimates for Operators with Simple
  Characteristics

abstract:
  We prove $L^{2}$ estimates and solvability for a variety of simply
characteristic constant coefficient partial differential equations $P(D)u=f$.
These estimates \[||u||_{L^2(D_{r})}\le C\sqrt{d_{r}d_{s}}
||f||_{_{L^2(D_{s})}}\] depend on geometric quantities - the diameters $d_{r}$
and $d_{s}$ of the regions $D_{r}$, where we estimate $u$, and $D_{s}$, the
support of $f$ - rather than weights. As these geometric quantities transform
simply under translations, rotations, and dilations, the corresponding
estimates share the same properties. In particular, this implies that they
transform appropriately under change of units, and therefore are physically
meaningful. The explicit dependence on the diameters implies the correct global
growth estimates. The weighted $L^{2}$ estimates first proved by Agmon in order
to construct the generalized eigenfunctions for Laplacian plus potential in
$\mathbb{R}^{n}$, and the more general and precise Besov type estimates of
Agmon and H\"ormander, are all simple direct corollaries of the estimate above.


title: A Comprehensive Survey on Cross-modal Retrieval

abstract:
  In recent years, cross-modal retrieval has drawn much attention due to the
rapid growth of multimodal data. It takes one type of data as the query to
retrieve relevant data of another type. For example, a user can use a text to
retrieve relevant pictures or videos. Since the query and its retrieved results
can be of different modalities, how to measure the content similarity between
different modalities of data remains a challenge. Various methods have been
proposed to deal with such a problem. In this paper, we first review a number
of representative methods for cross-modal retrieval and classify them into two
main groups: 1) real-valued representation learning, and 2) binary
representation learning. Real-valued representation learning methods aim to
learn real-valued common representations for different modalities of data. To
speed up the cross-modal retrieval, a number of binary representation learning
methods are proposed to map different modalities of data into a common Hamming
space. Then, we introduce several multimodal datasets in the community, and
show the experimental results on two commonly used multimodal datasets. The
comparison reveals the characteristic of different kinds of cross-modal
retrieval methods, which is expected to benefit both practical applications and
future research. Finally, we discuss open problems and future research
directions.


title: Some Representation Theorems for Sesquilinear Forms

abstract:
  The possibility of getting a Radon-Nikodym type theorem and a Lebesgue-like
decomposition for a non necessarily positive sesquilinear $\Omega$ form defined
on a vector space $\mathcal D$, with respect to a given positive form $\Theta$
defined on $\D$, is explored. The main result consists in showing that a
sesquilinear form $\Omega$ is $\Theta$-regular, in the sense that it has a
Radon-Nikodym type representation, if and only if it satisfies a sort
Cauchy-Schwarz inequality whose right hand side is implemented by a positive
sesquilinear form which is $\Theta$-absolutely continuous. In the particular
case where $\Theta$ is an inner product in $\mathcal D$, this class of
sesquilinear form covers all standard examples. In the case of a form defined
on a dense subspace $\mathcal D$ of Hilbert space $\mathcal H$ we give a
sufficient condition for the equality
$\Omega(\xi,\eta)=\langle{T\xi}|{\eta}\rangle$, with $T$ a closable operator,
to hold on a dense subspace of $\mathcal H$.


title:
Population Synthesis of Cataclysmic Variables: I. Inclusion of Detailed
  Nuclear Evolution

abstract:
  We have carried out an extensive population synthesis study of the ensemble
properties of the present-day population of cataclysmic variables (PDCVs) that
takes into account the nuclear evolution of high-mass donors close to the
bifurcation and dynamical instability limits. Assuming the interrupted magnetic
braking paradigm, we confirm many of the general features associated with the
observed CV population and find enormous diversity in their secular properties.
We predict that nearly half of the non-magnetic CVs with Porb > 6 hours are at
least mildly evolved (i.e., greater than one-half of their MS turn-off age).
  Some of these systems contribute to the observed population of PDCVs in the
period gap. We also see an enhancement by up to a factor of two in the
probability of detecting CVs at the `minimum period'. This spike is quite
narrow (approximately 5 minutes) and is attenuated because of the spectrum of
WD masses and partly by the evolution of the donors. Our syntheses imply that
there should be a very rapid decline in the number of ultracompact CVs (such as
AM CVns). We find that between 0.05 to 1 percent of PDCVs could be UCs, and
thus it is likely that the CV channel is probably not the primary contributor
to the intrinsic population of UCs (especially for Porb < 30 minutes). Finally,
a preliminary analysis of our results suggests that WDs in PDCVs experience a
net gain in mass of less than about 0.1 Msun as a result of high mass-transfer
rates early in their evolution.


title: Phenomenology of dark matter in chiral U(1)$_X$ dark sector

abstract:
  We consider dark matter physics in a model for the dark sector with extra
dark U(1)$_X$ gauge symmetry. The dark sector is composed of exotic fermions
that are charged under both dark U(1)$_X$ and the standard model SU(3)$_C
\times$U(1)$_Y$ gauge groups, as well as standard model singlet complex scalars
$\Phi$ and $X$ with nonzero U(1)$_X$ charge. In this model, there are two dark
matter candidates$-$a scalar and a fermion$-$both of which are stabilized by
accidental $Z_2$ symmetry. Their thermal relic density, and direct and indirect
detection constraints are discussed in detail and we search for the parameter
space of the model accommodating dark matter observations. We also discuss
constraints from diphoton resonance searches associated with the scalar field
which breaks the dark U(1)$_X$, in a way consistent with dark matter physics.
In addition, implications for collider physics are discussed, focusing on the
production cross section of the scalar boson.


title:
Social Behavior Analysis in Visual Human Monitoring System : A Survey
  and Perspective

abstract:
  A social behavior analysis is used to study how a group of people interacts
with another group. The analysis helps to understand how social behavior leads
to its consequences such as what business decision is made after a
businessmen's meeting. In this paper, we focus on visual human motion analysis
which is one important component of social behavior analysis. Human motion
analysis in visual surveillance usually tracks the motion of an individual or a
group of people, yet social behavior is usually neglected. This paper first
delivers a literature survey of visual surveillance, with emphasis on aspects
of human motion analysis and social behavior. Second, it offers a perspective
for social behavior analysis in an intelligent visual human monitoring system.
Third, a social interaction is induced by a social behavior between two
persons, one person and one group, or two groups, hence three general scenarios
of social interactions are outlined for future theoretical development. The
proposed human monitoring system enables the generation of valuable quantified
information of social interactions. It provides an objective approach to
evaluate performance of a human organization such as a company or a school.
Finally, it can raise the awareness of researchers to further explore the field
of social behavior analysis.


title:
Submillimeter H2O and H2O+ emission in lensed ultra- and hyper-luminous
  infrared galaxies at z ~ 2-4

abstract:
  (abridged) We report rest-frame submillimeter H2O emission line observations
of 11 HyLIRGs/ULIRGs at z~2-4 selected among the brightest lensed galaxies
discovered in the Herschel-ATLAS. Using the IRAM NOEMA, we have detected 14 new
H2O emission lines. The apparent luminosities of the H2O emission lines are
$\mu L_{\rm{H_2O}} \sim 6-21 \times 10^8 L_\odot$, with velocity-integrated
line fluxes ranging from 4-15 Jy km s$^{-1}$. We have also observed CO emission
lines using EMIR on the IRAM 30m telescope in seven sources. The velocity
widths for CO and H2O lines are found to be similar. With almost comparable
integrated flux densities to those of the high-J CO line, H2O is found to be
among the strongest molecular emitters in high-z Hy/ULIRGs. We also confirm our
previously found correlation between luminosity of H2O ($L_{\rm{H_2O}}$) and
infrared ($L_{\rm{IR}}$) that $L_{\rm{H_2O}} \sim L_{\rm{IR}}^{1.1-1.2}$, with
our new detections. This correlation could be explained by a dominant role of
far-infrared (FIR) pumping in the H2O excitation. Modelling reveals the FIR
radiation fields have warm dust temperature $T_\rm{warm}$~45-75 K, H2O column
density per unit velocity interval $N_{\rm{H_2O}}/\Delta V \gtrsim 0.3 \times
10^{15}$ cm$^{-2}$ km$^{-1}$ s and 100 $\mu$m continuum opacity $\tau_{100} >
1$ (optically thick), indicating that H2O is likely to trace highly obscured
warm dense gas. However, further observations of $J\geq4$ H2O lines are needed
to better constrain the continuum optical depth and other physical conditions
of the molecular gas and dust. We have also detected H2O+ emission in three
sources. A tight correlation between $L_{\rm{H_2O}}$ and $L_{\rm{H_2O^+}}$ has
been found in galaxies from low to high redshift. The velocity-integrated flux
density ratio between H2O+ and H2O suggests that cosmic rays generated by
strong star formation are possibly driving the H2O+ formation.


title: A Perspective on Sentiment Analysis

abstract:
  Sentiment Analysis (SA) is indeed a fascinating area of research which has
stolen the attention of researchers as it has many facets and more importantly
it promises economic stakes in the corporate and governance sector. SA has been
stemmed out of text analytics and established itself as a separate identity and
a domain of research. The wide ranging results of SA have proved to influence
the way some critical decisions are taken. Hence, it has become relevant in
thorough understanding of the different dimensions of the input, output and the
processes and approaches of SA.


title: Hints of quantum gravity from the horizon fluid

abstract:
  For many years researchers have tried to glean hints about quantum gravity
from black hole thermodynamics. However, black hole thermodynamics suffers from
the problem of Universality --- at leading order, several approaches with
different microscopic degrees of freedom lead to Bekenstein-Hawking entropy. We
attempt to bypass this issue by using a minimal statistical mechanical model
for the horizon fluid based on Damour-Navier-Stokes (DNS) equation. For
stationary asymptotically flat black hole spacetimes in General Relativity, we
show explicitly that at equilibrium the entropy of the horizon fluid is the
Bekenstein-Hawking entropy. Further we show that, for the bulk viscosity of the
fluctuations of the horizon fluid to be identical to Damour, a confinement
scale exists for these fluctuations, implying quantization of the horizon area.
The implications and possible mechanisms from the fluid point of view are
discussed.


title:
Negative differential conductivity and quantum statistical effects in a
  three-site Bose-Hubbard model

abstract:
  The use of an electron beam to remove ultracold atoms from selected sites in
an optical lattice has opened up new opportunities to study transport in
quantum systems [R. Labouvie {\it et al.\ }, Phys.\ Rev.\ Lett.\ {\bf 115},
050601 (2015)]. Inspired by this experimental result, we examine the effects of
number difference, dephasing, and initial quantum statistics on the filling of
an initially depleted middle well in the three-well inline Bose-Hubbard model.
We find that the well-known phenomenon of macroscopic self-trapping is the main
contributor to oscillatory negative differential conductivity in our model,
with phase diffusion being a secondary effect. However, we find that phase
diffusion is required for the production of direct atomic current, with the
coherent process showing damped oscillatory currents. We also find that our
results are highly dependent on the initial quantum states of the atoms in the
system.


title:
Large and moderate deviations for bounded functions of slowly mixing
  markov chains

abstract:
  We consider Markov chains which are polynomially mixing, in a weak sense
expressed in terms of the space of functions on which the mixing speed is
controlled. In this context, we prove polynomial large and moderate deviations
inequalities. These inequalities can be applied in various natural situations
coming from probability theory or dynamical systems. Finally, we discuss
examples from these various settings showing that our inequalities are sharp.


title: Species survival and scaling laws in hostile and disordered environments

abstract:
  In this work we study the likelihood of survival of single-species in the
context of hostile and disordered environments. Population dynamics in this
environment, as modeled by the Fisher equation, is characterized by negative
average growth rate, except in some random spatially distributed patches that
may support life. In particular, we are interested in the phase diagram of the
survival probability and in the critical size problem, i.e., the minimum patch
size required for surviving in the long time dynamics. We propose a measure for
the critical patch size as being proportional to the participation ratio (PR)
of the eigenvector corresponding to the largest eigenvalue of the linearized
Fisher dynamics. We obtain the (extinction-survival) phase diagram and the
probability distribution function (PDF) of the critical patch sizes for two
topologies, namely, the one-dimensional system and the fractal Peano basin. We
show that both topologies share the same qualitative features, but the fractal
topology requires higher spatial fluctuations to guarantee species survival. We
perform a finite-size scaling and we obtain the associated scaling exponents.
In addition, we show that the PDF of the critical patch sizes has an universal
shape for the 1D case in terms of the model parameters (diffusion, growth rate,
etc.). In contrast, the diffusion coefficient has a drastic effect on the PDF
of the critical patch sizes of the fractal Peano basin, and it does not obey
the same scaling law of the 1D case.


title:
Line Spectral Estimation Based on Compressed Sensing with Deterministic
  Sub-Nyquist Sampling

abstract:
  As an alternative to the traditional sampling theory, compressed sensing
allows acquiring much smaller amount of data, still estimating the spectra of
frequency-sparse signals accurately. However, compressed sensing usually
requires random sampling in data acquisition, which is difficult to implement
in hardware. In this paper, we propose a deterministic and simple sampling
scheme, that is, sampling at three sub-Nyquist rates which have coprime
undersampled ratios. This sampling method turns out to be valid through
numerical experiments. A complex-valued multitask algorithm based on
variational Bayesian inference is proposed to estimate the spectra of
frequency-sparse signals after sampling. Simulations show that this method is
feasible and robust at quite low sampling rates.