title:
Convex Analysis in Decentralized Stochastic Control, Strategic Measures
  and Optimal Solutions

abstract:
  This paper is concerned with the properties of the sets of strategic measures
induced by admissible team policies in decentralized stochastic control and the
convexity properties in dynamic team problems. To facilitate a convex
analytical approach, strategic measures for team problems are introduced.
Properties such as convexity, and compactness and Borel measurability under
weak convergence topology are studied, and sufficient conditions for each of
these properties are presented. These lead to existence of and structural
results for optimal policies. It will be shown that the set of strategic
measures for teams which are not classical is in general non-convex, but the
extreme points of a relaxed set consist of deterministic team policies, which
lead to their optimality for a given team problem under an expected cost
criterion. Externally provided independent common randomness for static teams
or private randomness for dynamic teams do not improve the team performance.
The problem of when a sequential team problem is convex is studied and
necessary and sufficient conditions for problems which include teams with a
non-classical information structure are presented. Implications of this
analysis in identifying probability and information structure dependent
convexity properties are presented.


title: On the dynamics of finite temperature trapped Bose gases

abstract:
  The system that describes the dynamics of a Bose-Einstein Condensate (BEC)
and the thermal cloud at finite temperature consists of a nonlinear Schrodinger
(NLS) and a quantum Boltzmann (QB) equations. In such a system of trapped Bose
gases at finite temperature, the QB equation corresponds to the evolution of
the density distribution function of the thermal cloud and the NLS is the
equation of the condensate. The quantum Boltzmann collision operator in this
temperature regime is the sum of two operators $C_{12}$ and $C_{22}$, which
describe collisions of the condensate and the non-condenstate atoms and
collisions between non-condensate atoms. Above the BEC critical temperature,
the system is reduced to an equation containing only $C_{22}$, which possesses
a blow-up positive radial solution with respect to the $L^\infty$ norm (cf.
\cite{EscobedoVelazquez:2015:FTB}). On the other hand, at the very low
temperature regime, the system becomes an equation of $C_{12}$, with a
different (much higher order) transition probability, which has a unique global
positive radial solution with weighted $L^1$ norm (cf. \cite{AlonsoGambaBinh}).
In the current temperature regime, we first decouple the QB and NLS equations,
then show a global existence and uniqueness result for positive radial
solutions to the spatially homogeneous kinetic system. Different from the case
considered in \cite{EscobedoVelazquez:2015:FTB}, due to the presence of the
BEC, the collision integrals are associated to sophisticated energy manifolds
rather than spheres, since the particle energy is approximated by the
Bogoliubov dispersion law. Moreover, the mass of the full system is not
conserved while it is conserved for the case considered in
\cite{EscobedoVelazquez:2015:FTB}. A new theory is then supplied.


title: Reaction rates for reaction-diffusion kinetics on unstructured meshes

abstract:
  The reaction-diffusion master equation is a stochastic model often utilized
in the study of biochemical reaction networks in living cells. It is applied
when the spatial distribution of molecules is important to the dynamics of the
system. A viable approach to resolve the complex geometry of cells accurately
is to discretize space with an unstructured mesh. Diffusion is modeled as
discrete jumps between nodes on the mesh, and the diffusion jump rates can be
obtained through a discretization of the diffusion equation on the mesh.
Reactions can occur when molecules occupy the same voxel. In this paper, we
develop a method for computing accurate reaction rates between molecules
occupying the same voxel in an unstructured mesh. For large voxels, these rates
are known to be well approximated by the reaction rates derived by Collins and
Kimball, but as the mesh is refined, no analytical expression for the rates
exists. We reduce the problem of computing accurate reaction rates to a pure
preprocessing step, depending only on the mesh and not on the model parameters,
and we devise an efficient numerical scheme to estimate them to high accuracy.
We show in several numerical examples that as we refine the mesh, the results
obtained with the reaction-diffusion master equation approach those of a more
fine-grained Smoluchowski particle-tracking model.


title:
Structure Based Aesthetics and Support of Cognitive Tasks for Graph
  Evaluation

abstract:
  Drawing principles, or aesthetics, are important in graph drawing. They are
used as criteria for algorithm design and for quality evaluation. Current
aesthetics are described as visual properties that a drawing is required to
have to be visually pleasing. However, most of these aesthetics are originally
proposed without consideration of graph structure information. Therefore their
ability in visually revealing graph structural features are not guaranteed and
indeed mixed results have been reported in the literature regarding their
impact on user graph comprehension. In this paper, we propose to derive
aesthetics based on graph internal structural features. Further, graphs are
often evaluated based on controlled experiments with simple perception tasks to
avoid possible confounding factors caused by complex tasks. This leaves their
value in supporting complex tasks unevaluated. To fill this gap, we also
discuss the possibility of applying evaluation methodologies used in the
Cognitive Load Theory research for graph evaluation.


title:
Drift-diffusion equations on domains in $\mathbb{R}^d$: essential
  self-adjointness and stochastic completeness

abstract:
  We consider the problem of quantum and stochastic confinement for
drift-diffusion equations on domains $ \Omega \subset \mathbb R^d$. We obtain
various sufficient conditions on the behavior of the coefficients near the
boundary of $\Omega$ which ensure the essential self-adjointness or stochastic
completeness of the symmetric form of the drift-diffusion operator,
$-\frac{1}{\rho_\infty}\,\nabla\cdot \rho_\infty\mathbb D\nabla$. The proofs
are based on the method developed in [29] for quantum confinement on bounded
domains in $\mathbb R^d$. In particular for stochastic confinement we combine
the Liouville property with Agmon type exponential estimates for weak
solutions.


title: Warp Bridge Sampling: The Next Generation

abstract:
  Bridge sampling is an effective Monte Carlo method for estimating the ratio
of normalizing constants of two probability densities, a routine computational
problem in statistics, physics, chemistry, and other fields. The Monte Carlo
error of the bridge sampling estimator is determined by the amount of overlap
between the two densities. In the case of uni-modal densities, Warp-I, II, and
III transformations (Meng and Schilling, 2002) are effective for increasing the
initial overlap, but they are less so for multi-modal densities. This paper
introduces Warp-U transformations that aim to transform multi-modal densities
into Uni-modal ones without altering their normalizing constants. The
construction of a Warp-U transformation starts with a Normal (or other
convenient) mixture distribution $\phi_{\text{mix}}$ that has reasonable
overlap with the target density $p$, whose normalizing constant is unknown. The
stochastic transformation that maps $\phi_{\text{mix}}$ back to its generating
distribution $N(0,1)$ is then applied to $p$ yielding its Warp-U version, which
we denote $\tilde{p}$. Typically, $\tilde{p}$ is uni-modal and has
substantially increased overlap with $N(0,1)$. Furthermore, we prove that the
overlap between $\tilde{p}$ and $N(0,1)$ is guaranteed to be no less than the
overlap between $p$ and $\phi_{\text{mix}}$, in terms of any $f$-divergence. We
propose a computationally efficient method to find an appropriate
$\phi_{\text{mix}}$, and a simple but effective approach to remove the bias
which results from estimating the normalizing constants and fitting
$\phi_{\text{mix}}$ with the same data. We illustrate our findings using 10 and
50 dimensional highly irregular multi-modal densities, and demonstrate how
Warp-U sampling can be used to improve the final estimation step of the
Generalized Wang-Landau algorithm (Liang, 2005), a powerful sampling and
estimation method.


title: Ballistic gelatin as a putative substrate for EEG phantom devices

abstract:
  Phantom devices allow the human variable to be controlled for in order to
allow clear comparison and validation of biomedical imaging hardware and
software. There is currently no standard phantom for electroencephalography
(EEG). To be useful, such a device would need to: (a) accurately recreate the
real and imaginary components of scalp electrical impedance, (b) contain
internal emitters to create electrical dipoles, and (c) be easily replicable
across various labs and research groups. Cost-effective materials, which are
conductive, repeatable, and easily formed are a missing key enabler for EEG
phantoms. Here, we explore the use of ballistics gelatin, an inexpensive,
easily-formable and repeatable material, as a putative substrate by examining
its electrical properties and physical stability over time. We show that varied
concentrations of NaCl salt relative to gelatin powder shifts the
phase/frequency response profile, allowing for selective tuning of the material
electrical properties.


title: Chiral phase transition in QED$_3$ at finite temperature

abstract:
  Chiral phase transition in (2+1)-dimensional quantum electrodynamics
(QED$_3$) at finite temperature is investigated in the framework of truncated
Dyson-Schwinger equations (DSEs). We go beyond the widely used instantaneous
approximation and adopt a method that retains the full frequency dependence of
the fermion self-energy. We also take further step to include the effects of
wave-function renormalizations and introduce a minimal dressing of the bare
vertex. Finally, with the more complete solutions of the truncated DSEs, we
revisit the study of chiral phase transition in finite-temperature QED$_3$.


title: Rescuing the nonjet (NJ) azimuth quadrupole from the flow narrative

abstract:
  According to the flow narrative commonly applied to high-energy nuclear
collisions a cylindrical-quadrupole component of 1D azimuth angular
correlations is conventionally denoted by quantity $v_2$ and interpreted to
represent elliptic flow. Jet angular correlations may also contribute to $v_2$
data as "nonflow" depending on the method used to calculate $v_2$, but 2D
graphical methods are available to insure accurate separation. The nonjet (NJ)
quadrupole has various properties inconsistent with a flow interpretation,
including the observation that NJ quadrupole centrality variation in A-A
collisions has no relation to strongly-varying jet modification ("jet
quenching") in those collisions commonly attributed to jet interaction with a
flowing dense medium. In this presentation I describe isolation of quadrupole
spectra from pt-differential $v_2(p_t)$ data from the RHIC and LHC. I
demonstrate that quadrupole spectra have characteristics very different from
the single-particle spectra for most hadrons, that quadrupole spectra indicate
a common boosted hadron source for a small minority of hadrons that "carry" the
NJ quadrupole structure, that the narrow source-boost distribution is
characteristic of an expanding thin cylindrical shell (strongly contradicting
hydro descriptions), and that in the boost frame a single universal quadrupole
spectrum (L\'evy distribution) on transverse mass $m_t$ accurately describes
data for several hadron species scaled according to their statistical-model
abundances. The quadrupole spectrum shape changes very little from RHIC to LHC
energies. Taken in combination those characteristics strongly suggest a unique
{\em nonflow} (and nonjet) QCD mechanism for the NJ quadrupole conventionally
represented by $v_2$.


title: Infinitely many reducts of homogeneous structures

abstract:
  It is shown that the countably infinite dimensional pointed vector space (the
vector space equipped with a constant) over a finite field has infinitely many
first order definable reducts. This implies that the countable homogeneous
Boolean-algebra has infinitely many reducts. Our construction over the
2-element field is related to the Reed--Muller codes.


title: Coverage and Field Estimation on Bounded Domains by Diffusive Swarms

abstract:
  In this paper, we consider stochastic coverage of bounded domains by a
diffusing swarm of robots that take local measurements of an underlying scalar
field. We introduce three control methodologies with diffusion, advection, and
reaction as independent control inputs. We analyze the diffusion-based control
strategy using standard operator semigroup-theoretic arguments. We show that
the diffusion coefficient can be chosen to be dependent only on the robots'
local measurements to ensure that the swarm density converges to a function
proportional to the scalar field. The boundedness of the domain precludes the
need to impose assumptions on decaying properties of the scalar field at
infinity. Moreover, exponential convergence of the swarm density to the
equilibrium follows from properties of the spectrum of the semigroup generator.
In addition, we use the proposed coverage method to construct a
time-inhomogenous diffusion process and apply the observability of the heat
equation to reconstruct the scalar field over the entire domain from
observations of the robots' random motion over a small subset of the domain. We
verify our results through simulations of the coverage scenario on a 2D domain
and the field estimation scenario on a 1D domain.


title:
The independence process in conditional quantile location-scale models
  and an application to testing for monotonicity

abstract:
  In this paper the nonparametric quantile regression model is considered in a
location-scale context. The asymptotic properties of the empirical independence
process based on covariates and estimated residuals are investigated. In
particular an asymptotic expansion and weak convergence to a Gaussian process
are proved. The results can, on the one hand, be applied to test for validity
of the location-scale model. On the other hand, they allow to derive various
specification tests in conditional quantile location-scale models. In detail a
test for monotonicity of the conditional quantile curve is investigated. For
the test for validity of the location-scale model as well as for the
monotonicity test smooth residual bootstrap versions of Kolmogorov-Smirnov and
Cramer-von Mises type test statistics are suggested. We give rigorous proofs
for bootstrap versions of the weak convergence results. The performance of the
tests is demonstrated in a simulation study.


title:
A New Model of Urban Population Density Indicating Latent Fractal
  Structure

abstract:
  Fractal structure of a system suggests the optimal way in which parts
arranged or put together to form a whole. The ideas from fractals have a
potential application to the researches on urban sustainable development. To
characterize fractal cities, we need the measure of fractional dimension.
However, if the fractal organization is concealed in the complex spatial
distributions of geographical phenomena, the common methods of evaluating
fractal parameter will be disabled. In this article, a new model is proposed to
describe urban density and estimate fractal dimension of urban form. If urban
density takes on quasi-fractal pattern or the self-similar pattern is hidden in
the negative exponential distribution, the generalized gamma function may be
employed to model the urban landscape and estimate its latent fractal
dimension. As a case study, the method is applied to the city of Hangzhou,
China. The results show that urban form evolves from simple to complex
structure with time.


title: Explosive events in active region observed by IRIS and SST/CRISP

abstract:
  Transition-region explosive events (EEs) are characterized by non-Gaussian
line profiles with enhanced wings at Doppler velocities of 50-150 km/s. They
are believed to be the signature of solar phenomena that are one of the main
contributors to coronal heating. The aim of this study is to investigate the
link of EEs to dynamic phenomena in the transition region and chromosphere in
an active region. We analyze observations simultaneously taken by the Interface
Region Imaging Spectrograph (IRIS) in the Si IV 1394\AA\ line and the slit-jaw
(SJ) 1400\AA\ images, and the Swedish 1-m Solar Telescope (SST) in the
H$\alpha$ line. In total 24 events were found. They are associated with
small-scale loop brightenings in SJ 1400\AA\ images. Only four events show a
counterpart in the H$\alpha$-35 km/s and H$\alpha$+35 km/s images. Two of them
represent brightenings in the conjunction region of several loops that are also
related to a bright region (granular lane) in the H$\alpha$-35km/s and
H$\alpha$+35 km/s images. Sixteen are general loop brightenings that do not
show any discernible response in the H$\alpha$ images. Six EEs appear as
propagating loop brightenings, from which two are associated with dark jet-like
features clearly seen in the H$\alpha$-35 km/s images. We found that
chromospheric events with jet-like appearance seen in the wings of the
H$\alpha$ line can trigger EEs in the transition region and in this case the
IRIS Si IV 1394\AA\ line profiles are seeded with absorption components
resulting from Fe II and Ni II. Our study indicates that EEs occurring in
active regions have mostly upper-chromosphere/transition-region origin. We
suggest that magnetic reconnection resulting from the braidings of small-scale
transition region loops is one of the possible mechanisms of energy release
that are responsible for the EEs reported in this paper.


title: The action of matrix groups on aspherical manifolds

abstract:
  Let $\mathrm{SL}_{n}(\mathbb{Z})$ $(n\geq 3)$ be the special linear group and
$M^{r}$ be a closed aspherical manifold. It is proved that when $r<n,$ a group
action of $\mathrm{SL}_{n}(\mathbb{Z})$ on $M^{r}$ by homeomorphisms is trivial
if and only if the induced group homomorphism $\mathrm{SL}_{n}(%
\mathbb{Z})\rightarrow \mathrm{Out}(\pi _{1}(M))$ is trivial. For (almost) flat
manifolds, we prove a similar result in terms of holonomy groups. Especially,
when $\pi _{1}(M)$ is nilpotent, the group $\mathrm{SL}_{n}(% \mathbb{Z})$
cannot act nontrivially on $M$ when $r<n.$ This confirms a conjecture related
to Zimmer's program for these manifolds.


title: Spontaneous breakdown of topological protection in two dimensions

abstract:
  Due to time-reversal symmetry (TRS), two dimensional topological insulators
support counter-propagating helical edge modes. Here we show that, unlike the
infinitely sharp edge potential utilized in traditional calculations, an
experimentally more realistic smooth edge potential gives rise to edge
reconstruction and, consequently, spontaneous TRS breaking. Such edge
reconstruction may lead to breaking of the expected perfect conductance
quantization, to a finite Hall resistance at zero magnetic field, and to a
likely spin current. This calculation underpins the fragility of the
topological protection in realistic systems, which is of crucial importance in
proposed applications.


title:
Large-Scale Machine Translation between Arabic and Hebrew: Available
  Corpora and Initial Results

abstract:
  Machine translation between Arabic and Hebrew has so far been limited by a
lack of parallel corpora, despite the political and cultural importance of this
language pair. Previous work relied on manually-crafted grammars or pivoting
via English, both of which are unsatisfactory for building a scalable and
accurate MT system. In this work, we compare standard phrase-based and neural
systems on Arabic-Hebrew translation. We experiment with tokenization by
external tools and sub-word modeling by character-level neural models, and show
that both methods lead to improved translation performance, with a small
advantage to the neural models.


title: A four--dimensional Neumann ovaloid

abstract:
  What is the shape of a uniformly massive object that generates a
gravitational potential equivalent to that of two equal point-masses? If the
weight of each point-mass is sufficiently small compared to the distance
between the points then the answer is a pair of balls of equal radius, one
centered at each of the two points, but otherwise it is a certain domain of
revolution about the axis passing through the two points. The existence and
uniqueness of such a domain is known, but an explicit parameterization is known
only in the plane where the region is referred to as a Neumann oval. We
construct a four-dimensional "Neumann ovaloid", solving explicitly this inverse
potential problem.


abstract:
  In this paper, we prove that Linearization Stability of Einstein Field
Equations is a Generic Property in the sense that within the class
$\mathcal{V}$ of space-times which admit a compact Cauchy hypersurface of
constant mean curvature, the subclass $\mathcal{V}_K$ of space-times which are
linearization stable forms an open and dense subset of $\mathcal{V}$ under
$C^\infty$ - topology. The work is based upon the work of Ebin $[1]$, Fischer,
Marsden and Moncrief $[2,3]$ and Beig, Chrusciel and Schoen $[4]$.


title:
The Relation Between the Quasi-localized Energy Complexes and the
  Thermodynamic Potential for the Schwarzschild-de Sitter Black Hole

abstract:
  The Schwarzschild-de Sitter (SdS) black hole solution, which has two event
horizons, is considered to examine the relation between the quasi-localized
energy complexes on ${\cal M}$ and the heat flows passing through its boundary
$\partial {\cal M}$. Here ${\cal M}$ is the patch between cosmological event
horizon and black hole event horizon of the SdS black hole solution.
Conclusively, the relation, like the Legendre transformation, between the
quasi-localized Einstein and M{\o}ller energy complex and the heat flows
passing through the boundary is obeyed, and these two quasi-localized energy
complexes could be corresponding to thermodynamic potentials.


title: The AGN Jet Model of the Fermi Bubbles

abstract:
  The nature and origin of the Fermi bubbles detected in the inner Galaxy
remain elusive. In this paper, we briefly discuss some recent theoretical and
observational developments, with a focus on the AGN jet model. Analogous to
radio lobes observed in massive galaxies, the Fermi bubbles could be naturally
produced by a pair of opposing jets emanating nearly along the Galaxy's
rotation axis from the Galactic center. Our two-fluid hydrodynamic simulations
reproduce quite well the bubble location and shape, and interface instabilities
at the bubble surface could be effectively suppressed by shear viscosity. We
briefly comment on some potential issues related to our model, which may lead
to future progress.


title:
Learning by Stimulation Avoidance: A Principle to Control Spiking Neural
  Networks Dynamics

abstract:
  Learning based on networks of real neurons, and by extension biologically
inspired models of neural networks, has yet to find general learning rules
leading to widespread applications. In this paper, we argue for the existence
of a principle allowing to steer the dynamics of a biologically inspired neural
network. Using carefully timed external stimulation, the network can be driven
towards a desired dynamical state. We term this principle "Learning by
Stimulation Avoidance" (LSA). We demonstrate through simulation that the
minimal sufficient conditions leading to LSA in artificial networks are also
sufficient to reproduce learning results similar to those obtained in
biological neurons by Shahaf and Marom [1]. We examine the mechanism's basic
dynamics in a reduced network, and demonstrate how it scales up to a network of
100 neurons. We show that LSA has a higher explanatory power than existing
hypotheses about the response of biological neural networks to external
simulation, and can be used as a learning rule for an embodied application:
learning of wall avoidance by a simulated robot. The surge in popularity of
artificial neural networks is mostly directed to disembodied models of neurons
with biologically irrelevant dynamics: to the authors' knowledge, this is the
first work demonstrating sensory-motor learning with random spiking networks
through pure Hebbian learning.


title:
Structures, Branching Ratios and Laser Cooling Scheme for 138BaF
  Molecule

abstract:
  For laser cooling considerations, we have theoretically investigated the
electronic, rovibrational and hypefine structures of BaF molecule. The highly
diagonal Franck-Condon factors and the branching ratios for all possible
transitions within the lowest-lying four electronic states have also been
calculated. Meanwhile, the mixing between metastable A'2{\Delta} and A2{\Pi}
states and further the lifetime of the {\Delta} state have been estimated since
the loss procedure via {\Delta} state would like fatally destroy the main
quasi-cycling {\Sigma}-{\Pi} transition for cooling and trapping. The resultant
hyperfine splittings of each rovibrational states in X2{\Sigma}+ state provide
benchmarksfor sideband modulations of cooling and repumping lasers and remixing
microwaves to address all necessary levels. The calculated Zeeman shift and
g-factors for both X and A states serve as benchmarks for selections of the
trapping laser polarizations. Our study paves the way for future laser cooling
and magneto-optical trapping of the BaF molecule.


title: Neutrino Mass Sum Rules

abstract:
  Neutrino mass sum rules are an important class of predictions in flavour
models relating the Majorana phases to the neutrino masses. This leads, for
instance, to enormous restrictions on the effective mass as probed in
experiments on neutrinoless double beta decay. While up to now these sum rules
have in practically all cases been taken to hold exactly, we will go here
beyond that. While the effect of the renormalisation group running can be
visible, the qualitative features do not change. This changes somewhat for
model dependent corrections which might alter even the qualitative predictions
but only for large corrections and a high neutrino mass scale close to the edge
of the current limits. This finding backs up the solidity of the predictions
derived in the literature apart from some exceptions, and it thus marks a very
important step in deriving testable and robust predictions from neutrino
flavour models.


title: Depth contours in arrangements of halfplanes

abstract:
  Let $H$ be a set of $n$ halfplanes in $\mathbb{R}^2$ in general position, and
let $k<n$ be a given parameter. We show that the number of vertices of the
arrangement of $H$ that lie at depth exactly $k$ (i.e., that are contained in
the interiors of exactly $k$ halfplanes of $H$) is $O(nk^{1/3} +
n^{2/3}k^{4/3})$. The bound is tight when $k=\Theta(n)$. This generalizes the
study of Dey [Dey98], concerning the complexity of a single level in an
arrangement of lines, and coincides with it for $k=O(n^{1/3})$.


title: Performance Impact of Idle Mode Capability on Dense Small Cell Networks

abstract:
  Very recent studies showed that in a fully loaded dense small cell network
(SCN), the coverage probability performance will continuously decrease with the
network densification. Such new results were captured in IEEE ComSoc Technology
News with an alarming title of "Will Densification Be the Death of 5G?". In
this paper, we revisit this issue from more practical views of realistic
network deployment, such as a finite number of active base stations (BSs) and
user equipments (UEs), a decreasing BS transmission power with the network
densification, etc. Particularly, in dense SCNs, due to an oversupply of BSs
with respect to UEs, a large number of BSs can be put into idle modes without
signal transmission, if there is no active UE within their coverage areas.
Setting those BSs into idle modes mitigates unnecessary inter-cell interference
and reduces energy consumption. In this paper, we investigate the performance
impact of such BS idle mode capability (IMC) on dense SCNs. Different from
existing work, we consider a realistic path loss model incorporating both
line-of-sight (LoS) and non-line-of-sight (NLoS) transmissions. Moreover, we
obtain analytical results for the coverage probability, the area spectral
efficiency (ASE) and the energy efficiency (EE) performance for SCNs with the
BS IMC and show that the performance impact of the IMC on dense SCNs is
significant. As the BS density surpasses the UE density in dense SCNs, the
coverage probability will continuously increase toward one, addressing previous
concerns on "the death of 5G". Finally, the performance improvement in terms of
the EE performance is also investigated for dense SCNs using practical energy
models developed in the Green-Touch project.


title:
Simultaneous Spectrum Sensing and Data Reception for Cognitive Spatial
  Multiplexing Distributed Systems

abstract:
  A multi-user cognitive (secondary) radio system is considered, where the
spatial multiplexing mode of operation is implemented amongst the nodes, under
the presence of multiple primary transmissions. The secondary receiver carries
out minimum mean-squared error (MMSE) detection to effectively decode the
secondary data streams, while it performs spectrum sensing at the remaining
signal to capture the presence of primary activity or not. New analytical
closed-form expressions regarding some important system measures are obtained,
namely, the outage and detection probabilities; the transmission power of the
secondary nodes; the probability of unexpected interference at the primary
nodes; {\color{blue}and the detection efficiency with the aid of the area under
the receive operating characteristics curve}. The realistic scenarios of
channel fading time variation and channel estimation errors are encountered for
the derived results. Finally, the enclosed numerical results verify the
accuracy of the proposed framework, while some useful engineering insights are
also revealed, such as the key role of the detection accuracy to the overall
performance and the impact of transmission power from the secondary nodes to
the primary system.


title: Internet of Things Cloud: Architecture and Implementation

abstract:
  The Internet of Things (IoT), which enables common objects to be intelligent
and interactive, is considered the next evolution of the Internet. Its
pervasiveness and abilities to collect and analyze data which can be converted
into information have motivated a plethora of IoT applications. For the
successful deployment and management of these applications, cloud computing
techniques are indispensable since they provide high computational capabilities
as well as large storage capacity. This paper aims at providing insights about
the architecture, implementation and performance of the IoT cloud. Several
potential application scenarios of IoT cloud are studied, and an architecture
is discussed regarding the functionality of each component. Moreover, the
implementation details of the IoT cloud are presented along with the services
that it offers. The main contributions of this paper lie in the combination of
the Hypertext Transfer Protocol (HTTP) and Message Queuing Telemetry Transport
(MQTT) servers to offer IoT services in the architecture of the IoT cloud with
various techniques to guarantee high performance. Finally, experimental results
are given in order to demonstrate the service capabilities of the IoT cloud
under certain conditions.


title:
First-principles study on magnetic tunneling junctions with
  semiconducting CuInSe${}_{2}$ and CuGaSe${}_{2}$ barriers

abstract:
  We theoretically investigate two different magnetic tunneling junctions
(MTJs) with semiconductor barriers, CuInSe${}_{2}$ (CIS) and CuGaSe${}_{2}$
(CGS), which are the terminal compounds of recently reported mixed
semiconductor barrier, CuIn${}_{1-x}$Ga$_{\it x}$Se${}_{2}$. To discuss the
transport properties of these systems, we analyze complex band structures,
magnetoresistance (MR) ratios, and resistance-area products ($RA$) by using
first-principles based calculations in combination with the Landauer formula.
It is found that the $\Delta_{1}$ wave functions have dominant contributions to
the spin-dependent tunneling transport in both CIS- and CGS-based MTJs. We also
find that the CGS-based MTJ has a much larger MR ratio and slightly higher $RA$
than those of the CIS-based MTJ, which indicates that a larger MR ratio is
expected for a higher Ga concentration $x$ in the
CuIn${}_{1-x}$Ga${}_{x}$Se${}_{2}$-based MTJs. We further study the
relationship between the band gaps in the barriers and MR ratios by changing
the Coulomb repulsions in the Cu 3$d$ states of the CIS and CGS. It is shown
that the barrier with a larger band gap yields a larger MR ratio. The
comparison of MR ratios and $RA$ between the CIS-, CGS-, and MgO-based MTJs are
also given.


title:
Inference for spatial processes using imperfect data from measurements
  and numerical simulations

abstract:
  We present a framework for inference for spatial processes that have actual
values imperfectly represented by data. Environmental processes represented as
spatial fields, either at fixed time points, or aggregated over fixed time
periods, are studied. Data from both measurements and simulations performed by
complex computer models are used to infer actual values of the spatial fields.
  Methods from geostatistics and statistical emulation are used to explicitly
capture discrepancies between a spatial field's actual and simulated values. A
geostatistical model captures spatial discrepancy: the difference in spatial
structure between simulated and actual values. An emulator represents the
intensity discrepancy: the bias in simulated values of given intensity.
Measurement error is also represented. Gaussian process priors represent each
source of error, which gives an analytical expression for the posterior
distribution for the actual spatial field.
  Actual footprints for 50 European windstorms, which represent maximum wind
gust speeds on a grid over a 72-hour period, are derived from wind gust speed
measurements taken at stations across Europe and output simulated from a
downscaled version of the Met Office Unified Model. The derived footprints have
realistic spatial structure, and gust speeds closer to the measurements than
originally simulated.


title:
Multi-Rate Control over AWGN Channels via Analog Joint Source-Channel
  Coding

abstract:
  We consider the problem of controlling an unstable plant over an additive
white Gaussian noise (AWGN) channel with a transmit power constraint, where the
signaling rate of communication is larger than the sampling rate (for
generating observations and applying control inputs) of the underlying plant.
Such a situation is quite common since sampling is done at a rate that captures
the dynamics of the plant and which is often much lower than the rate that can
be communicated. This setting offers the opportunity of improving the system
performance by employing multiple channel uses to convey a single message
(output plant observation or control input). Common ways of doing so are
through either repeating the message, or by quantizing it to a number of bits
and then transmitting a channel coded version of the bits whose length is
commensurate with the number of channel uses per sampled message. We argue that
such "separated source and channel coding" can be suboptimal and propose to
perform joint source-channel coding. Since the block length is short we obviate
the need to go to the digital domain altogether and instead consider analog
joint source-channel coding. For the case where the communication signaling
rate is twice the sampling rate, we employ the Archimedean bi-spiral-based
Shannon-Kotel'nikov analog maps to show significant improvement in stability
margins and linear-quadratic Gaussian (LQG) costs over simple schemes that
employ repetition.


title:
The polarization effects of the process $\tau \rightarrow K^{-} \pi^{0}
  \nu_{\tau}$ in the Nambu--Jona-Lasinio model

abstract:
  The polarization effects of the processes $\tau \rightarrow K^{-} \pi^{0}
\nu_{\tau}$ are described in the framework of the Nambu--Jona-Lasinio model.
The intermediate vector meson $K^{*}(892)$ is taken into account. The
contribution of these effects to the differential decay width is obtained.


title:
A key role of transversality condition in quantization of photon orbital
  angular momentum

abstract:
  The effect of the transversality condition on the quantization of the photon
orbital angular momentum is studied. The quantum gauge that is deduced from the
transversality condition is shown to be a Berry gauge. It determines a
helicity-dependent reference point relative to which the position is
canonically conjugate to the momentum. As a result, the photon orbital angular
momentum about the origin of the laboratory reference system split into two
parts. One is the orbital angular momentum of the photon about the reference
point, which is canonical. The other is the orbital angular momentum of the
photon concentrated at the reference point, which is dependent on the helicity.
Only when the Berry-gauge degree of freedom of a paraxial beam is perpendicular
to the propagation direction, does the total orbital angular momentum reduce to
its canonical part. One of the observable effects of the Berry-gauge degree of
freedom is also clarified.


title:
Characteristic dynamics near two coalescing eigenvalues incorporating
  continuum threshold effects

abstract:
  It has been reported in the literature that the survival probability $P(t)$
near an exceptional point where two eigenstates coalesce should generally
exhibit an evolution $P(t) \sim t^2 e^{-\Gamma t}$, in which $\Gamma$ is the
decay rate of the coalesced eigenstate; this has been verified in a microwave
billiard experiment [B. Dietz, et al, Phys. Rev. E 75, 027201 (2007)]. However,
the heuristic effective Hamiltonian that is usually employed to obtain this
result ignores the possible influence of the continuum threshold on the
dynamics. By contrast, in this work we employ an analytical approach starting
from the microscopic Hamiltonian representing two simple models in order to
show that the continuum threshold has a strong influence on the dynamics near
exceptional points in a variety of circumstances. To report our results, we
divide the exceptional points in Hermitian open quantum systems into two cases:
at an EP2A two virtual bound states coalesce before forming a resonance,
anti-resonance pair with complex conjugate eigenvalues, while at an EP2B two
resonances coalesce before forming two different resonances. For the EP2B,
which is the case studied in the microwave billiard experiment, we verify the
survival probability exhibits the previously reported modified exponential
decay on intermediate timescales, but this is replaced with an inverse power
law on very long timescales. Meanwhile, for the EP2A the influence from the
continuum threshold is so strong that the evolution is non-exponential on all
timescales and the heuristic approach fails completely. When the EP2A appears
very near the threshold we obtain the novel evolution $P(t) \sim 1 - C_1
\sqrt{t} + D_1 t$ on intermediate timescales, while further away the parabolic
decay (Zeno dynamics) on short timescales is enhanced. We also discuss the
parametric encirclement of the EP2A in an appendix.


title:
Multiscale modeling, discretization, and algorithms: a survey in
  biomechanics

abstract:
  Multiscale models allow for the treatment of complex phenomena involving
different scales, such as remodeling and growth of tissues, muscular
activation, and cardiac electrophysiology. Numerous numerical approaches have
been developed to simulate multiscale problems. However, compared to the
well-established methods for classical problems, many questions have yet to be
answered. Here, we give an overview of existing models and methods, with
particular emphasis on mechanical and bio-mechanical applications. Moreover, we
discuss state-of-the-art techniques for multilevel and multifidelity
uncertainty quantification. In particular, we focus on the similarities that
can be found across multiscale models, discretizations, solvers, and
statistical methods for uncertainty quantification. Similarly to the current
trend of removing the segregation between discretizations and solution methods
in scientific computing, we anticipate that the future of multiscale simulation
will provide a closer interaction with also the models and the statistical
methods. This will yield better strategies for transferring the information
across different scales and for a more seamless transition in selecting and
adapting the level of details in the models. Finally, we note that machine
learning and Bayesian techniques have shown a promising capability to capture
complex model dependencies and enrich the results with statistical information;
therefore, they can complement traditional physics-based and numerical analysis
approaches.


title: SegMatch: Segment based loop-closure for 3D point clouds

abstract:
  Loop-closure detection on 3D data is a challenging task that has been
commonly approached by adapting image-based solutions. Methods based on local
features suffer from ambiguity and from robustness to environment changes while
methods based on global features are viewpoint dependent. We propose SegMatch,
a reliable loop-closure detection algorithm based on the matching of 3D
segments. Segments provide a good compromise between local and global
descriptions, incorporating their strengths while reducing their individual
drawbacks.
  SegMatch does not rely on assumptions of "perfect segmentation", or on the
existence of "objects" in the environment, which allows for reliable execution
on large scale, unstructured environments. We quantitatively demonstrate that
SegMatch can achieve accurate localization at a frequency of 1Hz on the largest
sequence of the KITTI odometry dataset. We furthermore show how this algorithm
can reliably detect and close loops in real-time, during online operation. In
addition, the source code for the SegMatch algorithm will be made available
after publication.


title: Testing Quantum Models of Conjunction Fallacy on the World Wide Web

abstract:
  The 'conjunction fallacy' has been extensively debated by scholars in
cognitive science and, in recent times, the discussion has been enriched by the
proposal of modeling the fallacy using the quantum formalism. Two major quantum
approaches have been put forward: the first assumes that respondents use a
two-step sequential reasoning and that the fallacy results from the presence of
'question order effects'; the second assumes that respondents evaluate the
cognitive situation as a whole and that the fallacy results from the 'emergence
of new meanings', as an 'effect of overextension' in the conceptual
conjunction. Thus, the question arises as to determine whether and to what
extent conjunction fallacies would result from 'order effects' or, instead,
from 'emergence effects'. To help clarify this situation, we propose to use the
World Wide Web as an 'information space' that can be interrogated both in a
sequential and non-sequential way, to test these two quantum approaches. We
find that 'emergence effects', and not 'order effects', should be considered
the main cognitive mechanism producing the observed conjunction fallacies.


title: Sooner than Expected: Hitting the Wall of Complexity in Evolution

abstract:
  In evolutionary robotics an encoding of the control software, which maps
sensor data (input) to motor control values (output), is shaped by stochastic
optimization methods to complete a predefined task. This approach is assumed to
be beneficial compared to standard methods of controller design in those cases
where no a-priori model is available that could help to optimize performance.
Also for robots that have to operate in unpredictable environments, an
evolutionary robotics approach is favorable. We demonstrate here that such a
model-free approach is not a free lunch, as already simple tasks can represent
unsolvable barriers for fully open-ended uninformed evolutionary computation
techniques. We propose here the 'Wankelmut' task as an objective for an
evolutionary approach that starts from scratch without pre-shaped controller
software or any other informed approach that would force the behavior to be
evolved in a desired way. Our focal claim is that 'Wankelmut' represents the
simplest set of problems that makes plain-vanilla evolutionary computation
fail. We demonstrate this by a series of simple standard evolutionary
approaches using different fitness functions and standard artificial neural
networks as well as continuous-time recurrent neural networks. All our tested
approaches failed. We claim that any other evolutionary approach will also fail
that does per-se not favor or enforce modularity and does not freeze or protect
already evolved functionalities. Thus we propose a hard-to-pass benchmark and
make a strong statement for self-complexifying and generative approaches in
evolutionary computation. We anticipate that defining such a 'simplest task to
fail' is a valuable benchmark for promoting future development in the field of
artificial intelligence, evolutionary robotics and artificial life.


title:
Well-Rounded Lattices: Towards Optimal Coset Codes for Gaussian and
  Fading Wiretap Channels

abstract:
  The design of lattice coset codes for wiretap channels is considered. Bounds
on the eavesdropper's correct decoding probability and information leakage are
first revisited. From these bounds, it is explicit that both the information
leakage and error probability are controlled by the average flatness factor of
the eavesdropper's lattice, which we further interpret geometrically. It is
concluded that the minimization of the (average) flatness factor of the
eavesdropper's lattice leads to the study of well-rounded lattices, which are
shown to be among the optimal in order to achieve these minima. Constructions
of some well-rounded lattices are also provided.


title: The RNN-ELM Classifier

abstract:
  In this paper we examine learning methods combining the Random Neural
Network, a biologically inspired neural network and the Extreme Learning
Machine that achieve state of the art classification performance while
requiring much shorter training time. The Random Neural Network is a integrate
and fire computational model of a neural network whose mathematical structure
permits the efficient analysis of large ensembles of neurons. An activation
function is derived from the RNN and used in an Extreme Learning Machine. We
compare the performance of this combination against the ELM with various
activation functions, we reduce the input dimensionality via PCA and compare
its performance vs. autoencoder based versions of the RNN-ELM.


title:
Approximate energy states and thermal properties of a particle with
  position-dependent mass in external magnetic fields

abstract:
  We solve the Schr\"odinger equation with a position-dependent mass (PDM)
charged particle interacted via the superposition of the Morse and Coulomb
potentials and exposed to external magnetic and Aharonov-Bohm (AB) flux fields.
The non-relativistic bound state energies together with their wave functions
are calculated for two spatially-dependent mass distribution functions. We also
study the thermal quantities of such a system. Further, the canonical formalism
is used to compute various thermodynamic variables for second choosing mass by
using the Gibbs formalism. We give plots for energy as a function of various
physical parameters. The behavior of the internal energy, specific heat and
entropy as functions of temperature and mass density parameter in the
inverse-square mass case for different values of magnetic field are shown.


title:
Tuning phase transitions of FeSe thin flakes by field effect transistor
  with solid ion conductor as gate dielectric

abstract:
  We develop a novel field effect transistor (FET) device using solid ion
conductor (SIC) as a gate dielectric, and we can tune the carrier density of
FeSe by driving lithium ions in and out of the FeSe thin flakes, and
consequently control the material properties and its phase transitions. A
dome-shaped superconducting phase diagram was mapped out with increasing Li
content, with $T_c$ $\sim$ 46.6 K for the optimal doping, and an insulating
phase was reached at the extremely overdoped regime. Our study suggests that,
using solid ion conductor as a gate dielectric, the SIC-FET device can achieve
much higher carrier doping in the bulk, and suit many surface sensitive
experimental probes, and can stabilize novel structural phases that are
inaccessible in ordinary conditions.


title:
Deep learning based fence segmentation and removal from an image using a
  video sequence

abstract:
  Conventional approaches to image de-fencing use multiple adjacent frames for
segmentation of fences in the reference image and are limited to restoring
images of static scenes only. In this paper, we propose a de-fencing algorithm
for images of dynamic scenes using an occlusion-aware optical flow method. We
divide the problem of image de-fencing into the tasks of automated fence
segmentation from a single image, motion estimation under known occlusions and
fusion of data from multiple frames of a captured video of the scene.
Specifically, we use a pre-trained convolutional neural network to segment
fence pixels from a single image. The knowledge of spatial locations of fences
is used to subsequently estimate optical flow in the occluded frames of the
video for the final data fusion step. We cast the fence removal problem in an
optimization framework by modeling the formation of the degraded observations.
The inverse problem is solved using fast iterative shrinkage thresholding
algorithm (FISTA). Experimental results show the effectiveness of proposed
algorithm.


title: Semifinite Bundles and the Chevalley-Weil Formula

abstract:
  In our previous paper, we studied the category of semifinite bundles on a
proper variety defined over a field of characteristic 0. As a result, we
obtained the fact that for a smooth projective curve defined over an
algebraically closed field of characteristic 0 with genus $g>1$, Nori
fundamental group acts faithfully on the unipotent fundamental group of its
universal covering. However, it was not mentioned about any explicit module
structure. In this paper, we prove that the Chevalley-Weil formula gives a
description of it.


title: Hofstadter butterfly of a quasicrystal

abstract:
  The energy spectrum of a tight-binding Hamiltonian is studied for the
two-dimensional quasiperiodic Rauzy tiling in a perpendicular magnetic field.
This spectrum known as a Hofstadter butterfly displays a very rich pattern of
bulk gaps that are labeled by four integers, instead of two for periodic
systems. The role of phason-flip disorder is also investigated in order to
extract genuinely quasiperiodic properties. This geometric disorder is found to
only preserve main quantum Hall gaps.


title:
Lattice-Based Recurrent Neural Network Encoders for Neural Machine
  Translation

abstract:
  Neural machine translation (NMT) heavily relies on word-level modelling to
learn semantic representations of input sentences. However, for languages
without natural word delimiters (e.g., Chinese) where input sentences have to
be tokenized first, conventional NMT is confronted with two issues: 1) it is
difficult to find an optimal tokenization granularity for source sentence
modelling, and 2) errors in 1-best tokenizations may propagate to the encoder
of NMT. To handle these issues, we propose word-lattice based Recurrent Neural
Network (RNN) encoders for NMT, which generalize the standard RNN to word
lattice topology. The proposed encoders take as input a word lattice that
compactly encodes multiple tokenizations, and learn to generate new hidden
states from arbitrarily many inputs and hidden states in preceding time steps.
As such, the word-lattice based encoders not only alleviate the negative impact
of tokenization errors but also are more expressive and flexible to embed input
sentences. Experiment results on Chinese-English translation demonstrate the
superiorities of the proposed encoders over the conventional encoder.


title:
Cooperative Parallel Particle Filters for online model selection and
  applications to Urban Mobility

abstract:
  We design a sequential Monte Carlo scheme for the dual purpose of Bayesian
inference and model selection. We consider the application context of urban
mobility, where several modalities of transport and different measurement
devices can be employed. Therefore, we address the joint problem of online
tracking and detection of the current modality. For this purpose, we use
interacting parallel particle filters, each one addressing a different model.
They cooperate for providing a global estimator of the variable of interest
and, at the same time, an approximation of the posterior density of each model
given the data. The interaction occurs by a parsimonious distribution of the
computational effort, with online adaptation for the number of particles of
each filter according to the posterior probability of the corresponding model.
The resulting scheme is simple and flexible. We have tested the novel technique
in different numerical experiments with artificial and real data, which confirm
the robustness of the proposed scheme.


title: The generalized Auslander-Reiten duality on an exact category

abstract:
  We introduce a notion of generalized Auslander-Reiten duality on a Hom-finite
Krull-Schmidt exact category $\mathcal{C}$. This duality induces the
generalized Auslander-Reiten translation functors $\tau$ and $\tau^-$. They are
mutually quasi-inverse equivalences between the stable categories of two full
subcategories $\mathcal{C}_r$ and $\mathcal{C}_l$ of $\mathcal{C}$. A
non-projective indecomposable object lies in the domain of $\tau$ if and only
if it appears as the third term of an almost split conflation; dually, a
non-injective indecomposable object lies in the domain of $\tau^-$ if and only
if it appears as the first term of an almost split conflation.


title:
Model-independent determination of the compositeness of near-threshold
  quasibound states

abstract:
  We study the compositeness of near-threshold states to clarify the internal
structure of exotic hadron candidates. Within the framework of effective field
theory, we extend the Weinberg's weak-binding relation to include the nearby
CDD (Castillejo-Dalitz-Dyson) pole contribution with the help of the Pade
approximant. Finally, using the extended relation, we conclude that the CDD
pole contribution to the Lambda(1405) baryon in the Kbar N amplitude is
negligible.


title: Quantum Spin Hall Effect in Twisted Bilayer Graphene

abstract:
  Motivated by a recent experiment (Sanchez-Yamagishi et.al, arXiv:1602.06815)
reporting evidence of helical spin-polarized edge states in layer-biased
twisted bilayer graphene under a magnetic flux, we study the possibility of
stabilising a Quantum Spin Hall (QSH) phase in such a system, without Zeeman or
spin-orbit couplings, and with a QSH gap induced instead by electronic
interactions. We analyse how magnetic flux, electric field, interlayer rotation
angle, and interactions (treated at a mean field level) combine to produce a
pseudo-QSH with broken time-reversal symmetry, and spin-polarized helical edge
states. The effect is a consequence of a robust interaction-induced
ferrimagnetic ordering of the Quantum Hall ground state under an interlayer
bias, provided the two rotated layers are effectively decoupled at low
energies. We discuss in detail the electronic structure, and the constraints on
system parameters, such as the angle, interactions and magnetic flux, required
to reach the pseudo-QSH phase. We find, in particular, that purely local
electronic interactions are not sufficient to account for the experimental
observations, which demand at least nearest-neighbour interactions to be
included.


title: Magnetic Trapping of Cold Methyl Radicals

abstract:
  We have demonstrated that a supersonic beam of methyl radicals (CH$_3$) in
the ground rotational state of both $para$ and $ortho$ species has been slowed
down to standstill with a magnetic molecular decelerator, and successfully
captured spatially in an anti-Helmholtz magnetic trap for $>$ 1 s. The trapped
CH$_3$ radicals have a mean translational temperature of about 200 mK with an
estimated density of $>5.0\times10^7$ cm$^{-3}$. The methyl radical is an ideal
system for the study of cold molecules not only because of its high
reactivities at low temperatures, but also because further cooling below 1 mK
is plausible via sympathetic cooling with ultracold atoms. The demonstrated
trapping capability of methyl radicals opens up various possibilities for
realizing ultracold ensembles of molecules towards Bose-Einstein condensation
of polyatomic molecules and investigations of reactions governed by quantum
statistics.


title: Pro-aperiodic monoids via saturated models

abstract:
  We apply Stone duality and model theory to study the structure theory of free
pro-aperiodic monoids. Stone duality implies that elements of the free
pro-aperiodic monoid may be viewed as elementary equivalence classes of
pseudofinite words. Model theory provides us with saturated words in each such
class, i.e., words in which all possible factorizations are realized. We give
several applications of this new approach, including a solution to the word
problem for $\omega$-terms that avoids using McCammond's normal forms, as well
as new proofs and extensions of other structural results concerning free
pro-aperiodic monoids.


title: Holomorphic Jacobi Manifolds

abstract:
  In this paper, we develop holomorphic Jacobi structures. Holomorphic Jacobi
manifolds are in one-to-one correspondence with certain homogeneous holomorphic
Poisson manifolds. Furthermore, holomorphic Poisson manifolds can be looked at
as special cases of holomorphic Jacobi manifolds. We show that holomorphic
Jacobi structures yield a much richer framework than that of holomorphic
Poisson structures. We also discuss the relationship between holomorphic Jacobi
structures, generalized contact bundles and Jacobi-Nijenhuis structures.


title: Fast Blended Transformations for Partial Shape Registration

abstract:
  Automatic estimation of skinning transformations is a popular way to deform a
single reference shape into a new pose by providing a small number of control
parameters. We generalize this approach by efficiently enabling the use of
multiple exemplar shapes. Using a small set of representative natural poses, we
propose to express an unseen appearance by a low-dimensional linear subspace,
specified by a redundant dictionary of weighted vertex positions. Minimizing a
nonlinear functional that regulates the example manifold, the suggested
approach supports local-rigid deformations of articulated objects, as well as
nearly isometric embeddings of smooth shapes. A real-time non-rigid deformation
system is demonstrated, and a shape completion and partial registration
framework is introduced. These applications can recover a target pose and
implicit inverse kinematics from a small number of examples and just a few
vertex positions. The result reconstruction is more accurate compared to
state-of-the-art reduced deformable models.


title:
The possible detection of a binary companion to a Type Ibn supernova
  progenitor

abstract:
  We present late-time observations of the site of the Type Ibn supernova (SN)
2006jc acquired with the Hubble Space Telescope Advanced Camera for Surveys. A
faint blue source is recovered at the SN position with brightness
$m_{F435W}=26.76\pm0.20$, $m_{F555W}=26.60\pm0.23$ and $m_{F625W} =
26.32\pm0.19$ mags, although there is no detection in a contemporaneous
narrow-band $\mathrm{H\alpha}$ image. The spectral energy distribution of the
late-time source is well fit by a stellar-like spectrum ($\log T_{eff} > 3.7$
and $\log L / L_{\odot} > 4$) subject to only a small degree of reddening
consistent with that estimated for SN~2006jc itself at early-times. The lack of
further outbursts after the explosion of SN~2006jc suggests that the precursor
outburst originated from the progenitor. The possibility of the source being a
compact host cluster is ruled out on the basis of the source's faintness,
however the possibility that the late-time source maybe an unresolved light
echo originating in a shell or sphere of pre-SN dust (within a radius
$1\mathrm{pc}$) is also discussed. Irrespective of the nature of the late-time
source, these observations rule out a luminous blue variable as a companion to
the progenitor of SN~2006jc.


title:
A high mass progenitor for the Type Ic Supernova 2007gr inferred from
  its environment

abstract:
  We present an analysis of late-time Hubble Space Telescope Wide Field Camera
3 and Wide Field Planetary Camera 2 observations of the site of the Type Ic SN
2007gr in NGC 1058. The SN is barely recovered in the late-time WFPC2
observations, while a possible detection in the later WFC3 data is debatable.
These observations were used to conduct a multiwavelength study of the
surrounding stellar population. We fit spatial profiles to a nearby bright
source that was previously proposed to be a host cluster. We find that, rather
than being an extended cluster, it is consistent with a single point-like
object. Fitting stellar models to the observed spectral energy distribution of
this source, we conclude it is A1-A3 Yellow Supergiant, possibly corresponding
to a star with $M_{ZAMS} = 40M_{\odot}$. SN 2007gr is situated in a massive
star association, with diameter of $\approx 300\,\mathrm{pc}$. We present a
Bayesian scheme to determine the properties of the surrounding massive star
population, in conjunction with the Padova isochrones. We find that the stellar
population, as observed in either the WFC3 and WFPC2 observations, can be well
fit by two age distributions with mean ages: ~6.3 Myr and ~50 Myr. The stellar
population is clearly dominated by the younger age solution (by factors of 3.5
and 5.7 from the WFPC2 and WFC3 observations, respectively), which corresponds
to the lifetime of a star with $M_{ZAMS} \sim 30M_{\odot}$. This is strong
evidence in favour of the hypothesis that SN 2007gr arose from a massive
progenitor star, possibly capable of becoming a Wolf-Rayet star.


title:
Dielectric function with exact exchange contribution in the electron
  liquid. II. Analytical expression

abstract:
  The first-order, in terms of electron-interaction in the perturbation theory,
of the proper linear response function $\Pi ({\bf k}, \omega )$ gives rise to
the exchange-contribution to the dielectric function $\epsilon ({\bf k} ,
\omega)$ in the electron liquid. Its imaginary part, $Im \Pi_1 ({\bf k},
\omega)$, is calculated exactly. An analytical expression for $Im \Pi_1 ({\bf
k}, \omega)$ is derived which after refinement has a quite simple form.


title: Differentially Rotating White Dwarfs I: Regimes of Internal Rotation

abstract:
  Most viable models of Type Ia supernovae (SN~Ia) require the thermonuclear
explosion of a carbon/oxygen white dwarf that has evolved in a binary system.
Rotation could be an important aspect of any model for SN~Ia, whether single or
double degenerate, with the white dwarf mass at, below, or above the
Chandrasekhar limit. {\sl Differential rotation} is specifically invoked in
attempts to account for the apparent excess mass in the super--Chandrasekhar
events. Some earlier work has suggested that only uniform rotation is
consistent with the expected mechanisms of angular momentum transport in white
dwarfs, while others have found pronounced differential rotation. We show that
if the baroclinic instability is active in degenerate matter and the effects of
magnetic fields are neglected, both nearly-uniform and strongly-differential
rotation are possible. We classify rotation regimes in terms of the Richardson
number, Ri. At small values of Ri $\leq$ 0.1, we find both the low-viscosity
Zahn regime with a non-monotonic angular velocity profile and a new
differential rotation regime for which the viscosity is high and scales
linearly with the shear, $\sigma$. Employment of Kelvin-Helmholtz viscosity
alone yields differential rotation. Large values of Ri $\gg$ 1 produce a regime
of nearly-uniform rotation for which the baroclinic viscosity is of
intermediate value and scales as $\sigma^3$. We discuss the gap in
understanding of the behavior at intermediate values of Ri and how observations
may constrain the rotation regimes attained by nature.


title: Summer fireworks on comet 67P

abstract:
  During its two years mission around comet 67P/Churyumov-Gerasimenko, ESA's
Rosetta spacecraft had the unique opportunity to follow closely a comet in the
most active part of its orbit. Many studies have presented the typical features
associated to the activity of the nucleus, such as localized dust and gas jets.
Here we report on series of more energetic transient events observed during the
three months surrounding the comet's perihelion passage in August 2015.
  We detected and characterized 34 outbursts with the Rosetta cameras, one
every 2.4 nucleus rotation. We identified 3 main dust plume morphologies
associated to these events: a narrow jet, a broad fan, and more complex plumes
featuring both previous types together. These plumes are comparable in scale
and temporal variation to what has been observed on other comets.
  We present a map of the outbursts source locations, and discuss the
associated topography. We find that the spatial distribution sources on the
nucleus correlates well with morphological region boundaries, especially in
areas marked by steep scarps or cliffs.
  Outbursts occur either in the early morning or shortly after the local noon,
indicating two potential processes: Morning outbursts may be triggered by
thermal stresses linked to the rapid change of temperature, afternoon events
are most likely related to the diurnal or seasonal heat wave reaching volatiles
buried under the first surface layer. In addition, we propose that some events
can be the result of a completely different mechanism, in which most of the
dust is released upon the collapse of a cliff.


title:
Coexistence of bulk and surface polaritons in a~magnetic-semiconductor
  superlattice influenced by a transverse magnetic field

abstract:
  It is demonstrated that the effect of coexistence of bulk and surface
polaritons within the same frequency band and wavevector space can be achieved
in a magnetic-semiconductor superlattice providing a conscious choice of
characteristic resonant frequencies and material fractions of the structure's
underlying components as well as geometry of the external static magnetic
field. The study is based on the effective medium theory which is involved to
calculate dispersion characteristics of the long-wavelength electromagnetic
modes of ordinary and extraordinary bulk polaritons and hybrid EH and HE
surface polaritons derived via averaged expressions with respect to the
effective constitutive parameters of the superlattice.


title: Brownian motion as limit of the interchange process

abstract:
  We prove that the random empirical measure of appropriately rescaled particle
trajectories of the interchange process on path graphs converges weakly to the
deterministic measure of stationary Brownian motion on the unit interval. This
is a law of large numbers type result for particle trajectories of the
interchange process.
  After the completion of this manuscript we learned about a result of Durrett
and Neuhauser that implies this result.


title: On Hilbert coefficients of parameter ideals and Cohen-Macaulayness

abstract:
  Let $(R, \mathfrak m)$ be an unmixed Noetherian local ring, Q a parameter
ideal and $K$ an $\mathfrak m$-primary ideal of $R$ containing $Q$. We give a
necessary and sufficient condition for $R$ to be Cohen-Macaulay in terms of
$g_0(Q)$ and $g_1(Q)$, the Hilbert coefficients of $Q$ with respect to $K$. As
a consequence, we obtain a result of Ghezzi et al. which settles the negativity
conjecture of W. V. Vasconcelos [15] in unmixed local rings.


title: Finite Quotient of Join in Alexandrov Geometry

abstract:
  Given two $n_i$-dimensional Alexandrov spaces $X_i$ of curvature $\ge 1$, the
join of $X_1$ and $X_2$ is an $(n_1+n_2+1)$-dimensional Alexandrov space $X$ of
curvature $\ge 1$, which contains $X_i$ as convex subsets such that their
points are $\frac \pi2$ apart. If a group acts isometrically on a join that
preserves $X_i$, then the orbit space is called quotient of join. We show that
an $n$-dimensional Alexandrov space $X$ with curvature $\ge 1$ is isometric to
a finite quotient of join, if $X$ contains two compact convex subsets $X_i$
without boundary such that $X_1$ and $X_2$ are at least $\frac \pi2$ apart and
$\dim(X_1)+\dim(X_2)=n-1$.


title: The Accurate Particle Tracer Code

abstract:
  The Accurate Particle Tracer (APT) code is designed for large-scale particle
simulations on dynamical systems. Based on a large variety of advanced
geometric algorithms, APT possesses long-term numerical accuracy and stability,
which are critical for solving multi-scale and non-linear problems. Under the
well-designed integrated and modularized framework, APT serves as a universal
platform for researchers from different fields, such as plasma physics,
accelerator physics, space science, fusion energy research, computational
mathematics, software engineering, and high-performance computation. The APT
code consists of seven main modules, including the I/O module, the
initialization module, the particle pusher module, the parallelization module,
the field configuration module, the external force-field module, and the
extendible module. The I/O module, supported by Lua and Hdf5 projects, provides
a user-friendly interface for both numerical simulation and data analysis. A
series of new geometric numerical methods and key physical problems, such as
runaway electrons in tokamaks and energetic particles in Van Allen belt, have
been studied using APT. As an important realization, the APT-SW version has
been successfully distributed on the world's fastest computer, the Sunway
TaihuLight supercomputer, by supporting master-slave architecture of Sunway
many-core processors.


title: Quasiconvexity in the Heisenberg group

abstract:
  We show that if $A$ is a closed subset of the Heisenberg group whose vertical
projections are nowhere dense, then the complement of $A$ is quasiconvex. In
particular, closed sets which are null sets for the cc-Hausdorff $3$-measure
have quasiconvex complements. Conversely, we exhibit a compact totally
disconnected set of Hausdorff dimension three whose complement is not
quasiconvex.


title:
Accurate and Efficient Hyperbolic Tangent Activation Function on FPGA
  using the DCT Interpolation Filter

abstract:
  Implementing an accurate and fast activation function with low cost is a
crucial aspect to the implementation of Deep Neural Networks (DNNs) on FPGAs.
We propose a high-accuracy approximation approach for the hyperbolic tangent
activation function of artificial neurons in DNNs. It is based on the Discrete
Cosine Transform Interpolation Filter (DCTIF). The proposed architecture
combines simple arithmetic operations on stored samples of the hyperbolic
tangent function and on input data. The proposed DCTIF implementation achieves
two orders of magnitude greater precision than previous work while using the
same or fewer computational resources. Various combinations of DCTIF parameters
can be chosen to tradeoff the accuracy and complexity of the hyperbolic tangent
function. In one case, the proposed architecture approximates the hyperbolic
tangent activation function with 10E-5 maximum error while requiring only 1.52
Kbits memory and 57 LUTs of a Virtex-7 FPGA. We also discuss how the activation
function accuracy affects the performance of DNNs in terms of their training
and testing accuracies. We show that a high accuracy approximation can be
necessary in order to maintain the same DNN training and testing performances
realized by the exact function.


title: Chiral Symmetry Restoration for the large-$N$ pion gas

abstract:
  We analyze chiral restoration within the $O(N+1)/O(N)$ Non-Linear Sigma Model
for large $N$ as an effective theory for low-energy QCD at finite temperature
$T$. The free energy is constructed diagramatically to ${\cal O}(TM^3)$ in the
pion mass expansion, which allows to derive the quark condensate and the scalar
susceptibility in the chiral limit. At this order, we do not have to deal with
renormalization, neither from divergences from mass tadpoles nor from those of
higher order loop contributions. Our results for the critical behaviour are
consistent with expectations from lattice analysis and with previous works
where the susceptibility is saturated by the thermal $f_0(500)$ pole.


title: First passage time and stochastic resonance of excitable systems

abstract:
  We study noise induced thermally activated barrier crossing of a Brownian
particle that hops in a periodic ratchet potential where the ratchet potential
is coupled with a spatially uniform temperature. The viscous friction is
considered to decrease exponentially when the temperature $T$ of the medium
increases as proposed originally by Reynolds. The results obtained in this work
show that the mean first passage time of the particle is considerably lower
when the viscous friction is temperature dependent than that of the case where
the viscous friction is temperature independent. We then explore the thermally
activated barrier crossing rate of the system in the presence of time varying
signal. In this case, the interplay between noise and sinusoidal driving force
in the bistable system may lead the system into stochastic resonance provided
that the random tracks are adjusted in an optimal way to the recurring external
force.


title: Some Generalizations of the Enestr\"om-Kakeya Theorem

abstract:
  Let $p(z)=a_0+a_1z+a_2z^2+a_3z^3+\cdots+a_nz^n$ be a polynomial of degree
$n,$ where the coefficients $a_j,$ $j \in \{0,1,2,\cdots n\},$ are real
numbers. We impose some restriction on the coefficients and then prove some
extensions and generalizations of the Enestr\"{o}m-Kakeya Theorem.


title:
Finite Field Methods for the Supercell Modelling of Charged
  Insulator-Electrolyte Interfaces

abstract:
  Surfaces of ionic solids interacting with an ionic solution can build up
charge by exchange of ions. The surface charge is compensated by a strip of
excess charge at the border of the electrolyte forming an electric double
layer. These electric double layers are very hard to model using the supercells
methods of computational condensed phase science. The problem arises when the
solid is an electric insulator (as most ionic solids are) permitting a finite
interior electric field over the width of the slab representing the solid in
the supercell. The slab acts as a capacitor. The stored charge is a deficit in
the solution failing to compensate fully for the solid surface charge. Here we
show how these problems can be overcome using the finite field methods
developed by Stengel, Spaldin and Vanderbilt [Nat. Phys. {\bf 5}, 304, (2009)].
We also show how the capacitance of the double layer can be computed once
overall electric neutrality of the double layer is restored by application of a
finite macroscopic field $\mathbf{E}$ or alternatively by zero electric
displacement $\mathbf{D}$. The method is validated for a classical model of a
solid-electrolyte interface using the finite temperature molecular dynamics
adaptation of the constant field method presented previously [Phys. Rev. B,
2016, 93, 144201]. Because ions in electrolytes can diffuse across supercell
boundaries, this application turns out to be a critical illustration of the
multivaluedness of polarization in periodic systems.


title: On the number of zeros of a polynomial in a specified disk

abstract:
  Let $p(z)=a_0+a_1z+a_2z^2+a_3z^3+\cdots+a_nz^n$ be a polynomial of degree
$n,$ where the coefficients $a_j,$ $j \in \{0,1,2,\cdots n\},$ may be complex.
We impose some restriction on the coefficients of the real part of the given
polynomial and then estimate the maximum number of zeros such polynomial can
possibly have in a specified disk.


title:
A Factorized Model for Transitive Verbs in Compositional Distributional
  Semantics

abstract:
  We present a factorized compositional distributional semantics model for the
representation of transitive verb constructions. Our model first produces
(subject, verb) and (verb, object) vector representations based on the
similarity of the nouns in the construction to each of the nouns in the
vocabulary and the tendency of these nouns to take the subject and object roles
of the verb. These vectors are then combined into a final (subject,verb,object)
representation through simple vector operations. On two established tasks for
the transitive verb construction our model outperforms recent previous work.


title: The Integral Screened Configuration Interaction Method

abstract:
  We present the formulation and implementation of the Integral-Screened
Configuration-Interaction method (ISCI). The ISCI is a minimal-operational
count integral-driven direct Configuration-Interaction (CI) method with a
simple and rigorous integral screening (IS). With a novel derivation of the CI
equations we show that the time consuming $\sigma$-vector calculation is
separable up to an overall sign and that this separability can lead to a
rigorous IS. The rigorous IS leads to linear scaling in the $\sigma$-vector
step for large systems but can also lead to near linear scaling for smaller
systems for the standard CISD, CISDT and CISDTQ methods, where the exponent for
the scaling is 1.27, 1.48 and 1.98, respectively, even while retaining an
accuracy of $10^{-14}$ or less in the energy. In the ISCI the non-relativistic
CI problem can be broken into 42 generalized-matrix-vector products in the
$\sigma$-vector calculation, which can be separately optimized. Due to the IS
the ISCI can use dramatically larger orbital spaces combined with large CI
expansions, on a single cpu, as compared with traditional CI methods. Further,
it offers an intrinsic possibility for parallelization on modern computing
architectures. We show examples of how IS leads to linear or near linear
scaling with respect to the size of the simulation box in calculations on the
Beryllium atom.


title:
A direct fast FFT-based implementation for high order finite element
  method on rectangular parallelepipeds for PDE

abstract:
  We present a new direct logarithmically optimal in theory and fast in
practice algorithm to implement the high order finite element method on
multi-dimensional rectangular parallelepipeds for solving PDEs of the Poisson
kind. The key points are the fast direct and inverse FFT-based algorithms for
decomposition in eigenvectors of the 1D eigenvalue problems for the high order
FEM. The algorithm can further be used for numerous applications, in
particular, to implement the high order finite element methods for various
time-dependent PDEs.


title:
Form factors and transverse charge and magnetization densities in the
  hard-wall AdS/QCD model

abstract:
  We present a study of the flavor form factors in the framework of a hard-wall
AdS/QCD model and compare with the available experimental data. We obtain the
flavor form factors by decomposing the Dirac and Pauli form factors for the
nucleons using the charge and isospin symmetry. Further, we present a detailed
study of the flavor structures of the charge and anomalous magnetization
densities in the transverse plane. Both the unpolarized and the transversely
polarized nucleons are considered here. We compare the AdS/QCD results with two
standard phenomenological parametrizations.


title:
Effects of anisotropy and Coulomb interactions on quantum transport in a
  quadruple quantum-dot structure

abstract:
  We present analytical and numerical investigation of spectral and transport
properties of a quadruple quantum-dot (QQD) structure which is one of the
popular low-dimensional systems in the context of fundamental quantum physics
study, future electronic applications and quantum calculations. The density of
states, occupation numbers and conductance of the structure were analyzed using
the nonequilibrium Green's functions in the tight binding approach and the
equation-of-motion method. In particular the anisotropy of hopping integrals
and on-site electron energies as well as the effects of the finite intra- and
interdot Coulomb interactions were investigated. It was found out that the
anisotropy of the kinetic processes in the system leads to the Fano-Feshbach
asymmetrical peak. We demonstrated that the conductance of QQD device has a
wide insulating band with steep edges separating triple-peak structures if the
intradot Coulomb interactions are taken into account. The interdot Coulomb
correlations between the central QDs result in the broadening of this band and
the occurrence of an additional band with low conductance due to the Fano
antiresonances. It was shown that in this case the conductance of the
anisotropic QQD device can be dramatically changed by tuning the anisotropy of
on-site electron energies.


title:
The Discovery of Solar-like Activity Cycles Beyond the End of the Main
  Sequence?

abstract:
  The long-term magnetic behavior of objects near the cooler end of the stellar
main sequence is poorly understood. Most theoretical work on the generation of
magnetism in these ultracool dwarfs (spectral type >=M7 stars and brown dwarfs)
suggests that their magnetic fields should not change in strength and
direction. Using polarized radio emission measurements of their magnetic field
orientations, I demonstrate that these cool, low-mass, fully-convective objects
appear to undergo magnetic polarity reversals analogous to those that occur on
the Sun. This powerful new technique potentially indicates that the patterns of
magnetic activity displayed by the Sun continue to exist, despite the fully
convective interiors of these objects, in contravention of several leading
theories of the generation of magnetic fields by internal dynamos.


title:
The cosmological analysis of X-ray cluster surveys; III. 4D X-ray
  observable diagrams

abstract:
  Despite compelling theoretical arguments, the use of clusters as cosmological
probes is, in practice, frequently questioned because of the many uncertainties
impinging on cluster mass estimates. Our aim is to develop a fully
self-consistent cosmological approach of X-ray cluster surveys, exclusively
based on observable quantities, rather than masses. This procedure is justified
given the possibility to directly derive the cluster properties via ab initio
modelling, either analytically or by using hydrodynamical simulations. In this
third paper, we evaluate the method on cluster toy-catalogues. We model the
population of detected clusters in the count-rate -- hardness-ratio -- angular
size -- redshift space and compare the corresponding 4-dimensional diagram with
theoretical predictions. The best cosmology+physics parameter configuration is
determined using a simple minimisation procedure; errors on the parameters are
derived by scanning the likelihood hyper-surfaces with a wide range of starting
values. The method allows a simultaneous fit of the cosmological parameters, of
the cluster evolutionary physics and of the selection effects. When using
information from the X-ray survey alone plus redshifts, this approach is shown
to be as accurate as the mass function for the cosmological parameters and to
perform better for the cluster physics, as modelled in the scaling relations.
It enables the identification of degenerate combinations of parameter values.
Given the considerably shorter computer times involved for running the
minimisation procedure in the observed parameter space, this method appears to
clearly outperform traditional mass-based approaches when X-ray survey data
alone are available.


title:
Bifurcations in Delay Differential Equations: an algorithmic approach in
  frequency domain

abstract:
  In this work we study local oscillations in delay differential equations with
a frequency domain methodology. The main result is a bifurcation equation from
which the existence and expressions of local periodic solutions can be
determined. We present an iterative method to obtain the bifurcation equation
up to a fixed arbitrary order. It is shown how this method can be implemented
in symbolic math programs.


title: A criterion for zero averages and full support of ergodic measures

abstract:
  Consider a homeomorphism $f$ defined on a compact metric space $X$ and a
continuous map $\phi\colon X \to \mathbb{R}$. We provide an abstract criterion,
called \emph{control at any scale with a long sparse tail} for a point $x\in X$
and the map $\phi$, that guarantees that any weak$\ast$ limit measure $\mu$ of
the Birkhoff average of Dirac measures $\frac1n\sum_0^{n-1}\delta(f^i(x))$ is
such that $\mu$-almost every point $y$ has a dense orbit in $X$ and the
Birkhoff average of $\phi$ along the orbit of $y$ is zero.
  As an illustration of the strength of this criterion, we prove that the
diffeomorphisms with nonhyperbolic ergodic measures form a $C^1$-open and dense
subset of the set of robustly transitive partially hyperbolic diffeomorphisms
with one dimensional nonhyperbolic central direction. We also obtain
applications for nonhyperbolic homoclinic classes.


title: Moving Manifolds in Electromagnetic Fields

abstract:
  We propose dynamic non-linear equations for moving surfaces in
electromagnetic field. The field is induced by a material body with a boundary
of the surface. Correspondingly the potential energy, set by the field at the
boundary, can be written as an addition of four-potential times four-current to
a contraction of electromagnetic tensor. Proper application of minimal action
principle to the system Lagrangian yields dynamic non-linear equations for
moving three dimensional manifolds in electromagnetic fields. The equations, in
different conditions simplify to Maxwell equations for massless three surfaces,
to Euler equations for dynamic fluid, to magneto-hydrodynamic equations and to
Poisson-Boltzmann equation. To illustrate effectiveness of the equations of
motion we apply the formalism to analyze dynamics of macro-molecules and
membranes.


title: Separating Overlapped Intervals on a Line

abstract:
  Given $n$ intervals on a line $\ell$, we consider the problem of moving these
intervals on $\ell$ such that no two intervals overlap and the maximum moving
distance of the intervals is minimized. The difficulty for solving the problem
lies in determining the order of the intervals in an optimal solution. By
interesting observations, we show that it is sufficient to consider at most $n$
"candidate" lists of ordered intervals. Further, although explicitly
maintaining these lists takes $\Omega(n^2)$ time and space, by more
observations and a pruning technique, we present an algorithm that can compute
an optimal solution in $O(n\log n)$ time and $O(n)$ space. We also prove an
$\Omega(n\log n)$ time lower bound for solving the problem, which implies the
optimality of our algorithm.


title:
The age-mass-metallicity-activity relation for solar-type stars:
  Comparisons with asteroseismology and the NGC 188 open cluster

abstract:
  The Mount Wilson Ca II index log$(R'_{\rm HK})$ is the accepted standard
metric of calibration for the chromospheric activity versus age relation of FGK
stars. Recent results claim its inability to discern activity levels, and thus
ages, for stars older than $\sim$2 Gyr, which would severely hamper its
application to date disk stars older than the Sun. We present a new
activity-age calibration of the Mt. Wilson index explicitly taking into account
mass and $[$Fe/H$]$ biases, implicit in samples of stars selected to have
precise ages, that have so far gone unappreciated. We show that these selection
biases tend to blur the activity-age relation for large age ranges. We
calibrate the Mt. Wilson index for a sample of field FGK stars with precise
ages, covering a wide range of mass and $[$Fe/H$]$, augmented with data from
the Pleiades, Hyades, M67 clusters, and the Ursa Major moving group. We further
test the calibration with extensive new Gemini/GMOS log$(R'_{\rm HK})$ data of
the old, solar $[$Fe/H$]$ clusters M67 and NGC 188. The observed NGC 188
activity level is clearly lower than M67. We correctly recover the isochronal
age of both clusters and establish the viability of deriving usable
chromospheric ages for solar-type stars up to at least $\sim$6 Gyr, average
errors being $\sim$0.14 dex provided that the mass and $[$Fe/H$]$ dimensions
are explicitly accounted for. We test our calibration against
asteroseismological ages, finding excellent correlation ($\rho$ = +0.89). We
show that our calibration improves the chromospheric age determination for a
wide range of ages, masses, and metallicities in comparison to previous
age-activity relations.


title: On semitopological interassociates of the bicyclic monoid

abstract:
  Semitopological interassociates $\mathscr{C}_{m,n}$ of the bicyclic semigroup
$\mathscr{C}(p,q)$ are studied. In particular, we show that for arbitrary
non-negative integers $m$, $n$ and every Hausdorff topology $\tau$ on
$\mathscr{C}_{m,n}$ such that $\left(\mathscr{C}_{m,n},\tau\right)$ is a
semitopological semigroup, is discrete. Also, we prove that if an
interassociate of the bicyclic monoid $\mathscr{C}_{m,n}$ is a dense
subsemigroup of a Hausdorff semitopological semigroup $(S,\cdot)$ and
$I=S\setminus\mathscr{C}_{m,n}\neq\varnothing$ then $I$ is a two-sided ideal of
the semigroup $S$ and show that for arbitrary non-negative integers $m$, $n$,
any Hausdorff locally compact semitopological semigroup
$\mathscr{C}_{m,n}^0=\mathscr{C}_{m,n}\sqcup\{0\}$ is either discrete or
compact.


title: Deep Joint Rain Detection and Removal from a Single Image

abstract:
  In this paper, we address a rain removal problem from a single image, even in
the presence of heavy rain and rain streak accumulation. Our core ideas lie in
the new rain image models and a novel deep learning architecture. We first
modify an existing model comprising a rain streak layer and a background layer,
by adding a binary map that locates rain streak regions. Second, we create a
new model consisting of a component representing rain streak accumulation
(where individual streaks cannot be seen, and thus visually similar to mist or
fog), and another component representing various shapes and directions of
overlapping rain streaks, which usually happen in heavy rain. Based on the
first model, we develop a multi-task deep learning architecture that learns the
binary rain streak map, the appearance of rain streaks, and the clean
background, which is our ultimate output. The additional binary map is
critically beneficial, since its loss function can provide additional strong
information to the network. To handle rain streak accumulation (again, a
phenomenon visually similar to mist or fog) and various shapes and directions
of overlapping rain streaks, we propose a recurrent rain detection and removal
network that removes rain streaks and clears up the rain accumulation
iteratively and progressively. In each recurrence of our method, a new
contextualized dilated network is developed to exploit regional contextual
information and outputs better representation for rain detection. The
evaluation on real images, particularly on heavy rain, shows the effectiveness
of our novel models and architecture, outperforming the state-of-the-art
methods significantly. Our codes and data sets will be publicly available.


title: Random Forest for Malware Classification

abstract:
  The challenge in engaging malware activities involves the correct
identification and classification of different malware variants. Various
malwares incorporate code obfuscation methods that alters their code signatures
effectively countering antimalware detection techniques utilizing static
methods and signature database. In this study, we utilized an approach of
converting a malware binary into an image and use Random Forest to classify
various malware families. The resulting accuracy of 0.9562 exhibits the
effectivess of the method in detecting malware


title: Singularities of divisors on flag varieties via Hwang's product theorem

abstract:
  We give an alternative proof of a recent result by Pasquier stating that for
a generalized flag variety $X=G/P$ and an effective $\mathbb{Q}$-divisor $D$
stable with respect to a Borel subgroup the pair $(X,D)$ is Kawamata log
terminal if and only if $\lfloor D\rfloor=0$.


title:
Commonsense Reasoning, Commonsense Knowledge, and The SP Theory of
  Intelligence

abstract:
  This paper describes how the "SP Theory of Intelligence" with the "SP
Computer Model", outlined in an Appendix, may throw light on aspects of
commonsense reasoning (CSR) and commonsense knowledge (CSK), as discussed in
another paper by Ernest Davis and Gary Marcus (DM). In four main sections, the
paper describes: 1) The main problems to be solved; 2) Other research on CSR
and CSK; 3) Why the SP system may prove useful with CSR and CSK 4) How examples
described by DM may be modelled in the SP system. With regard to successes in
the automation of CSR described by DM, the SP system's strengths in
simplification and integration may promote seamless integration across these
areas, and seamless integration of those area with other aspects of
intelligence. In considering challenges in the automation of CSR described by
DM, the paper describes in detail, with examples of SP-multiple-alignments. how
the SP system may model processes of interpretation and reasoning arising from
the horse's head scene in "The Godfather" film. A solution is presented to the
'long tail' problem described by DM. The SP system has some potentially useful
things to say about several of DM's objectives for research in CSR and CSK.


title: Relic abundance of MeV millicharged particles

abstract:
  The relic abundance of light millicharged particles (MCPs) with the electric
charge $e' = 5\cdot 10^{-5} e$ and with the mass slightly below or above the
electron mass is calculated. The abundance depends on the mass ratio
$\eta=m_X/m_e$ and for $\eta<1$ can be high enough to allow MCPs to be the
cosmological dark matter or to make a noticeable contribution to it. On the
other hand, for $\eta \gtrsim 1$ the cosmological energy density of MCPs can be
quite low, $\Omega_X h_0^2 \approx 0.02$ for scalar MCPs, and $\Omega_X h_0^2
\approx 0.001$ for spin 1/2 fermions. But even the lowest value of $\Omega_X
h_0^2$ is in tension with several existing limits on the MCP abundances and
parameters. However, these limits have been derived under some natural or
reasonable assumptions on the properties of MCPs. If these assumptions are
relaxed, a patch in the mass-charge plot of MCPs may appear, permitting them to
be dark matter particles.


title:
Demonstrating non-Abelian braiding of surface code defects in a five
  qubit experiment

abstract:
  Currently, the mainstream approach to quantum computing is through surface
codes. One way to store and manipulate quantum information with these to create
defects in the codes which can be moved and used as if they were particles.
Specifically, they simulate the behaviour of exotic particles known as
Majoranas, which are a kind of non-Abelian anyon. By exchanging these
particles, important gates for quantum computation can be implemented. Here we
investigate the simplest possible exchange operation for two surface code
Majoranas. This is found to act non-trivially on only five qubits. The system
is then truncated to these five qubits, so that the exchange process can be run
on the IBM 5Q processor. The results demonstrate the expected effect of the
exchange. This paper has been written in a style that should hopefully be
accessible to both professional and amateur scientists.


title: Biunitary constructions in quantum information

abstract:
  We present an infinite number of construction schemes involving unitary error
bases, Hadamard matrices, quantum Latin squares and controlled families, many
of which have not previously been described. Our results rely on biunitary
connections, algebraic objects which play a central role in the theory of
planar algebras. They have an attractive graphical calculus which allows simple
correctness proofs for the constructions we present. We apply these techniques
to construct a unitary error basis that cannot be built using any previously
known method.


title:
Linear maps between C*-algebras that are *-homomorphisms at a fixed
  point

abstract:
  Let $A$ and $B$ be C$^*$-algebras. A linear map $T:A\to B$ is said to be a
$^*$-homomorphism at an element $z\in A$ if $a b^*=z$ in $A$ implies $T (a b^*)
=T (a) T (b)^* =T(z)$, and $ c^* d=z$ in $A$ gives $T (c^* d) =T (c)^* T (d)
=T(z).$ Assuming that $A$ is unital, we prove that every linear map $T: A\to B$
which is a $^*$-homomorphism at the unit of $A$ is a Jordan $^*$-homomorphism.
If $A$ is simple and infinite, then we establish that a linear map $T: A\to B$
is a $^*$-homomorphism if and only if $T$ is a $^*$-homomorphism at the unit of
$A$. For a general unital C$^*$-algebra $A$ and a linear map $T:A\to B$, we
prove that $T$ is a $^*$-homomorphism if, and only if, $T$ is a
$^*$-homomorphism at $0$ and at $1$. Actually if $p$ is a non-zero projection
in $A$, and $T$ is a $^*$-homomorphism at $p$ and at $1-p$, then we prove that
$T$ is a Jordan $^*$-homomorphism. We also study bounded linear maps that are
$^*$-homomorphisms at a unitary element in $A$.


title: Polydisc version of Arveson's conjecture

abstract:
  In the present paper, we solve the polydisc-version of Arveson Conjecture by
giving a complete criteria for essential normality of homogeneous quotient
modules of the Hardy module over the polydisc, and it turns out that our method
applies to quotient modules of the weighted Bergman modules $A^2_s(\mathbb
D^d)$.


title: On certain generalized isometries of the special orthogonal group

abstract:
  In this paper we explore the structure of certain generalized isometries of
the special orthogonal group $SO(n)$ which are transformations that leave any
member of a large class of generalized distance measures invariant. This gives
us a far-reaching generalization of the former structural result of T. Abe, S.
Akiyama and O. Hatori concerning $c$-spectral isometries of the special
orthogonal group.