title:
BICEP2 / Keck Array VIII: Measurement of gravitational lensing from
  large-scale B-mode polarization

abstract:
  We present measurements of polarization lensing using the 150 GHz maps which
include all data taken by the BICEP2 & Keck Array CMB polarization experiments
up to and including the 2014 observing season (BK14). Despite their modest
angular resolution ($\sim 0.5^\circ$), the excellent sensitivity ($\sim
3\mu$K-arcmin) of these maps makes it possible to directly reconstruct the
lensing potential using only information at larger angular scales ($\ell\leq
700$). From the auto-spectrum of the reconstructed potential we measure an
amplitude of the spectrum to be $A^{\phi\phi}_{\rm L}=1.15\pm 0.36$ (Planck
$\Lambda$CDM prediction corresponds to $A^{\phi\phi}_{\rm L}=1$), and reject
the no-lensing hypothesis at 5.8$\sigma$, which is the highest significance
achieved to date using an EB lensing estimator. Taking the cross-spectrum of
the reconstructed potential with the Planck 2015 lensing map yields
$A^{\phi\phi}_{\rm L}=1.13\pm 0.20$. These direct measurements of
$A^{\phi\phi}_{\rm L}$ are consistent with the $\Lambda$CDM cosmology, and with
that derived from the previously reported BK14 B-mode auto-spectrum ($A^{\rm
BB}_{\rm L}=1.20\pm 0.17$). We perform a series of null tests and consistency
checks to show that these results are robust against systematics and are
insensitive to analysis choices. These results unambiguously demonstrate that
the B-modes previously reported by BICEP / Keck at intermediate angular scales
($150\lesssim\ell\lesssim 350$) are dominated by gravitational lensing. The
good agreement between the lensing amplitudes obtained from the lensing
reconstruction and B-mode spectrum starts to place constraints on any
alternative cosmological sources of B-modes at these angular scales.


title: Power of Ordered Hypothesis Testing

abstract:
  Ordered testing procedures are multiple testing procedures that exploit a
pre-specified ordering of the null hypotheses, from most to least promising. We
analyze and compare the power of several recent proposals using the asymptotic
framework of Li & Barber (2015). While accumulation tests including ForwardStop
can be quite powerful when the ordering is very informative, they are
asymptotically powerless when the ordering is weaker. By contrast, Selective
SeqStep, proposed by Barber & Cand\`es (2015), is much less sensitive to the
quality of the ordering. We compare the power of these procedures in different
r\'egimes, concluding that Selective SeqStep dominates accumulation tests if
either the ordering is weak or non-null hypotheses are sparse or weak.
Motivated by our asymptotic analysis, we derive an improved version of
Selective SeqStep which we call Adaptive SeqStep, analogous to Storey's
improvement on the Benjamini-Hochberg procedure. We compare these methods using
the GEOQuery data set analyzed by Li & Barber (2015) and find Adaptive SeqStep
has favorable performance for both good and bad prior orderings.


title:
Stabilization of difference equations with noisy proportional feedback
  control

abstract:
  Given a deterministic difference equation $x_{n+1}= f(x_n)$, we would like to
stabilize any point $x^{\ast}\in (0, f(b))$, where $b$ is a unique maximum
point of $f$, by introducing proportional feedback (PF) control. We assume that
PF control contains either a multiplicative $x_{n+1}= f\left( (\nu +
\ell\chi_{n+1})x_n \right)$ or an additive noise $x_{n+1}=f(\lambda x_n)
+\ell\chi_{n+1}$. We study conditions under which the solution eventually
enters some interval, treated as a stochastic (blurred) equilibrium. In
addition, we prove that, for each $\varepsilon>0$, when the noise level $\ell$
is sufficiently small, all solutions eventually belong to the interval
$(x^{\ast}-\varepsilon,x^{\ast}+\varepsilon)$.


title:
Mal-Netminer: Malware Classification Approach based on Social Network
  Analysis of System Call Graph

abstract:
  As the security landscape evolves over time, where thousands of species of
malicious codes are seen every day, antivirus vendors strive to detect and
classify malware families for efficient and effective responses against malware
campaigns. To enrich this effort, and by capitalizing on ideas from the social
network analysis domain, we build a tool that can help classify malware
families using features driven from the graph structure of their system calls.
To achieve that, we first construct a system call graph that consists of system
calls found in the execution of the individual malware families. To explore
distinguishing features of various malware species, we study social network
properties as applied to the call graph, including the degree distribution,
degree centrality, average distance, clustering coefficient, network density,
and component ratio. We utilize features driven from those properties to build
a classifier for malware families. Our experimental results show that
influence-based graph metrics such as the degree centrality are effective for
classifying malware, whereas the general structural metrics of malware are less
effective for classifying malware. Our experiments demonstrate that the
proposed system performs well in detecting and classifying malware families
within each malware class with accuracy greater than 96%.


title: Scalable, Fast Cloud Computing with Execution Templates

abstract:
  Large scale cloud data analytics applications are often CPU bound. Most of
these cycles are wasted: benchmarks written in C++ run 10-51 times faster than
frameworks such as Naiad and Spark. However, calling faster implementations
from those frameworks only sees moderate (3-5x) speedups because their control
planes cannot schedule work fast enough.
  This paper presents execution templates, a control plane abstraction for
CPU-bound cloud applications, such as machine learning. Execution templates
leverage highly repetitive control flow to cache scheduling decisions as {\it
templates}. Rather than reschedule hundreds of thousands of tasks on every loop
execution, nodes instantiate these templates. A controller's template specifies
the execution across all worker nodes, which it partitions into per-worker
templates. To ensure that templates execute correctly, controllers dynamically
patch templates to match program control flow. We have implemented execution
templates in Nimbus, a C++ cloud computing framework. Running in Nimbus,
analytics benchmarks can run 16-43 times faster than in Naiad and Spark.
Nimbus's control plane can scale out to run these faster benchmarks on up to
100 nodes (800 cores).


title: Isometric copies of directed trees in orientations of graphs

abstract:
  For every $n\in\mathbb N$ we construct a finite graph $G$ such that every
orientation $\vec G$ of $G$ contains an isometric copy of any oriented tree on
$n$ vertices, and evaluate the smallest possible cardinality of $G$. On the
other hand, we prove that every graph $G$ admits an orientation containing no
directed $\omega$-paths of infinite diameter.


title: Tensor algebras and decorated representations

abstract:
  In arXiv:1506.05880 we gave a generalization of the theory of quivers with
potentials introduced by Derksen-Weyman-Zelevinsky, via completed tensor
algebras over $S$-bimodules where $S$ is a finite dimensional basic semisimple
algebra. In this paper we show how to extend this construction to the level of
decorated representations and we prove that mutation of decorated
representations is an involution. Moreover, we prove that there exists a nearly
Morita equivalence between the Jacobian algebras which are related via
mutation. This generalizes the construction given by Buan-Iyama-Reiten-Smith.


title: Absolute Combinatorial Game Theory

abstract:
  We propose a unifying additive theory for standard conventions in
Combinatorial Game Theory, including normal-, mis\`ere- and scoring-play,
studied by Berlekamp, Conway, Dorbec, Ettinger, Guy, Larsson, Milley, Neto,
Nowakowski, Renault, Santos, Siegel, Sopena, Stewart (1976-2019), and others. A
game {\em universe} is a set of games that satisfies some standard closure
properties. Here, we reveal when the fundamental game comparison problem, ``Is
$G\su H$?'', simplifies to a constructive `local' solution, which generalizes
Conway's foundational result in ONAG (1976) for normal-play games. This happens
in a broad and general fashion whenever a given game universe is {\em
absolute}. Games in an absolute universe satisfy two properties, dubbed {\em
parentality} and {\em saturation}, and we prove that the latter is implied by
the former. Parentality means that any pair of non-empty finite sets of games
is admissible as options, and saturation means that, given any game, the first
player can be favored in a disjunctive sum. Game comparison is at the core of
combinatorial game theory, and for example efficiency of potential reduction
theorems rely on a local comparison. We distinguish between three levels of
game comparison; superordinate (global), basic (semi-constructive) and
subordinate (local) comparison. In proofs, a sometimes tedious challenge faces
a researcher in CGT: in order to disprove an inequality, an explicit
distinguishing game might be required. Here, we explain how this job becomes
obsolete whenever a universe is absolute. Namely, it suffices to see if a pair
of games satisfies a certain Proviso together with a Maintenance of an
inequality.


title: Uniformity, Universality, and Computability Theory

abstract:
  We prove a number of results motivated by global questions of uniformity in
computability theory, and universality of countable Borel equivalence
relations. Our main technical tool is a game for constructing functions on free
products of countable groups.
  We begin by investigating the notion of uniform universality, first proposed
by Montalb\'an, Reimann and Slaman. This notion is a strengthened form of a
countable Borel equivalence relation being universal, which we conjecture is
equivalent to the usual notion. With this additional uniformity hypothesis, we
can answer many questions concerning how countable groups, probability
measures, the subset relation, and increasing unions interact with
universality. For many natural classes of countable Borel equivalence
relations, we can also classify exactly which are uniformly universal.
  We also show the existence of refinements of Martin's ultrafilter on Turing
invariant Borel sets to the invariant Borel sets of equivalence relations that
are much finer than Turing equivalence. For example, we construct such an
ultrafilter for the orbit equivalence relation of the shift action of the free
group on countably many generators. These ultrafilters imply a number of
structural properties for these equivalence relations.


title: Geometric Divisors in Normal Local Domains

abstract:
  Let A be the local ring at a point of a normal complex variety with
completion R. Srinivas has asked about the possible images of the induced map
from Cl A to Cl R over all geometric normal domains A with fixed completion R.
We use Noether-Lefschetz theory to prove that all finitely generated subgroups
are possible in some familiar cases. As a byproduct we show that every finitely
generated abelian group appears as the class group of the local ring at the
vertex of a cone over some smooth complex variety of each positive dimension.


title: Combinatorial descriptions of the crystal structure on certain PBW bases

abstract:
  Using the theory of PBW bases, one can realize the crystal $B(\infty)$ for
any semisimple Lie algebra over $\mathbf{C}$ using Kostant partitions as the
underlying set. In fact there are many such realizations, one for each reduced
expression for the longest element of the Weyl group. There is an algorithm to
calculate the actions of the crystal operators, but it can be quite
complicated. Here we show that, for certain reduced expressions, the crystal
operators can also be described by a much simpler bracketing rule. We give
conditions describing these reduced expressions, and show that there is at
least one example in every type except possibly $E_8$, $F_4$ and $G_2$. We then
discuss some examples.


title:
Exploring the Design Space of Longitudinal Censorship Measurement
  Platforms

abstract:
  Despite the high perceived value and increasing severity of online
information controls, a data-driven understanding of the phenomenon has
remained elusive. In this paper, we consider two design points in the space of
Internet censorship measurement with particular emphasis on how they address
the challenges of locating vantage points, choosing content to test, and
analyzing results. We discuss the trade offs of decisions made by each platform
and show how the resulting data provides complementary views of global
censorship. Finally, we discuss lessons learned and open challenges discovered
through our experiences.


title: Open-source Hardware: Opportunities and Challenges

abstract:
  Innovation in hardware is slowing due to rising costs of chip design and
diminishing benefits from Moore's law and Dennard scaling. Software innovation,
on the other hand, is flourishing, helped in good measure by a thriving
open-source ecosystem. We believe that open source can similarly help hardware
innovation, but has not yet due to several reasons. We identify these reasons
and how the industry, academia, and the hardware community at large can come
together to address them.


title:
Deep neural networks are robust to weight binarization and other
  non-linear distortions

abstract:
  Recent results show that deep neural networks achieve excellent performance
even when, during training, weights are quantized and projected to a binary
representation. Here, we show that this is just the tip of the iceberg: these
same networks, during testing, also exhibit a remarkable robustness to
distortions beyond quantization, including additive and multiplicative noise,
and a class of non-linear projections where binarization is just a special
case. To quantify this robustness, we show that one such network achieves 11%
test error on CIFAR-10 even with 0.68 effective bits per weight. Furthermore,
we find that a common training heuristic--namely, projecting quantized weights
during backpropagation--can be altered (or even removed) and networks still
achieve a base level of robustness during testing. Specifically, training with
weight projections other than quantization also works, as does simply clipping
the weights, both of which have never been reported before. We confirm our
results for CIFAR-10 and ImageNet datasets. Finally, drawing from these ideas,
we propose a stochastic projection rule that leads to a new state of the art
network with 7.64% test error on CIFAR-10 using no data augmentation.


title: Self-dual nonsymmetric operads with two binary operations

abstract:
  We consider nonsymmetric operads with two binary operations satisfying
relations in arity 3; hence these operads are quadratic, and so we can
investigate Koszul duality. We first consider operations which are
nonassociative (not necessarily associative) and then specialize to the
associative case. We obtain a complete classification of self-dual quadratic
nonsymmetric operads with two (associative or nonassociative) binary
operations. These operads generalize associativity for one operation to the
setting of two operations.


title:
The redshift selected sample of long gamma-ray burst host galaxies: the
  overall metallicity distribution at $z < 0.4$

abstract:
  We discuss the host galaxy metallicity distribution of all long gamma-ray
bursts (GRBs) whose redshifts are known to be $< 0.4$, including newly obtained
spectroscopic datasets of the host galaxies of GRB 060614, 090417B, and
130427A. We compare the metallicity distribution of the low-redshift sample to
the model predictions, and constrain the relation between metallicity and GRB
occurrence. We take account of spatial variation of metallicities among star
forming regions within a galaxy. We found that the models, in which only
low-metallicity stars produce GRBs with a sharp cutoff of GRB production
efficiency around 12+log(O/H) $\sim$ 8.3, can well reproduce the observed
distribution, while the models with no metallicity dependence are not
consistent with the observations. We also discuss possible sampling biases we
may suffer by collecting long GRBs whose redshifts are known, presenting the
photometric observations of the host galaxy of GRB 111225A at $z = 0.297$ whose
redshift has been undetermined until $\sim$ 2.3 years after the burst.


title: Expectile Matrix Factorization for Skewed Data Analysis

abstract:
  Matrix factorization is a popular approach to solving matrix estimation
problems based on partial observations. Existing matrix factorization is based
on least squares and aims to yield a low-rank matrix to interpret the
conditional sample means given the observations. However, in many real
applications with skewed and extreme data, least squares cannot explain their
central tendency or tail distributions, yielding undesired estimates. In this
paper, we propose \emph{expectile matrix factorization} by introducing
asymmetric least squares, a key concept in expectile regression analysis, into
the matrix factorization framework. We propose an efficient algorithm to solve
the new problem based on alternating minimization and quadratic programming. We
prove that our algorithm converges to a global optimum and exactly recovers the
true underlying low-rank matrices when noise is zero. For synthetic data with
skewed noise and a real-world dataset containing web service response times,
the proposed scheme achieves lower recovery errors than the existing matrix
factorization method based on least squares in a wide range of settings.


title: Adaptation is Useless for Two Discrete Additive-Noise Two-Way Channels

abstract:
  In two-way channels, each user transmits and receives at the same time. This
allows each encoder to interactively adapt the current input to its own message
and all previously received signals. Such coding approach can introduce
correlation between inputs of different users, since all the users' outputs are
correlated by the nature of the channel. However, for some channels, such
adaptation in the coding scheme and its induced correlation among users are
useless in the sense that they do not help enlarge the capacity region with
respect to the standard coding method (where each user encodes only based on
its own message). In this paper, it is shown that adaptation is not helpful for
enlarging the capacity region of two classes of two-way discrete channels: the
modulo additive-noise channel with memory and the multiple access/degraded
broadcast channel.


title: A Continuous Analogue of Lattice Path Enumeration: Part II

abstract:
  Here are exhibited some additional results about the continuous binomial
coefficients as introduced by L. Cano and R. Diaz in [1].


title:
Spatial spreading model and dynamics of West Nile virus in birds and
  mosquitoes with free boundary

abstract:
  In this paper, a reaction-diffusion system is proposed to model the spatial
spreading of West Nile virus in vector mosquitoes and host birds in North
America. Infection dynamics are based on a simplified model for cross infection
between mosquitoes and birds, and the free boundary is introduced to model and
explore the expanding front of the infective region. The spatial-temporal risk
index $R_0^F(t)$, which involves time and characters of the region, is defined
for the simplified model with the free boundary to compare with other related
threshold values, including the usual basic reproduction number $R_0$.
Sufficient conditions for the virus to vanish or spread are given. Our results
suggest that the virus will be in a scenario of vanishing if $R_0\leq 1$, and
the virus will spread to the whole region if $R_{0}^F(t_0)\geq 1$ for some
$t_0\geq 0$, while if $R^F_0(0)<1<R_0$, the spreading or vanishing of the virus
depends on the initial numbers of infected mosquitoes and birds, the area of
the infected region and diffusion rates. Moreover, some remarks on the basic
reproduction numbers and the spreading speed are presented and compared.


title:
Topologically twisted renormalization group flow and its holographic
  dual

abstract:
  Euclidean field theories admit more general deformations than usually
discussed in quantum field theories because of mixing between rotational
symmetry and internal symmetry (a.k.a topological twist). Such deformations may
be relevant, and if the subsequent renormalization group flow leads to a
non-trivial fixed point, it generically gives rise to a scale invariant
Euclidean field theory without conformal invariance. Motivated by an ansatz
studied in cosmological models some time ago, we develop a holographic dual
description of such renormalization group flows in the context of AdS/CFT. We
argue that the non-trivial fixed points require fine-tuning of the bulk theory
in general, but remarkably we find that the $O(3)$ Yang-Mills theory coupled
with the four-dimensional Einstein gravity in the minimal manner supports such
a background with the Euclidean AdS metric.


title: A Duality Web in 2+1 Dimensions and Condensed Matter Physics

abstract:
  Building on earlier work in the high energy and condensed matter communities,
we present a web of dualities in $2+1$ dimensions that generalize the known
particle/vortex duality. Some of the dualities relate theories of fermions to
theories of bosons. Others relate different theories of fermions. For example,
the long distance behavior of the $2+1$-dimensional analog of QED with a single
Dirac fermion (a theory known as $U(1)_{1/2}$) is identified with the $O(2)$
Wilson-Fisher fixed point. The gauged version of that fixed point with a
Chern-Simons coupling at level one is identified as a free Dirac fermion. The
latter theory also has a dual version as a fermion interacting with some gauge
fields. Assuming some of these dualities, other dualities can be derived. Our
analysis resolves a number of confusing issues in the literature including how
time reversal is realized in these theories. It also has many applications in
condensed matter physics like the theory of topological insulators (and their
gapped boundary states) and the problem of electrons in the lowest Landau level
at half filling. (Our techniques also clarify some points in the fractional
Hall effect and its description using flux attachment.) In addition to
presenting several consistency checks, we also present plausible (but not
rigorous) derivations of the dualities and relate them to $3+1$-dimensional
$S$-duality.


title:
Neural Network Models for Implicit Discourse Relation Classification in
  English and Chinese without Surface Features

abstract:
  Inferring implicit discourse relations in natural language text is the most
difficult subtask in discourse parsing. Surface features achieve good
performance, but they are not readily applicable to other languages without
semantic lexicons. Previous neural models require parses, surface features, or
a small label set to work well. Here, we propose neural network models that are
based on feedforward and long-short term memory architecture without any
surface features. To our surprise, our best configured feedforward architecture
outperforms LSTM-based model in most cases despite thorough tuning. Under
various fine-grained label sets and a cross-linguistic setting, our feedforward
models perform consistently better or at least just as well as systems that
require hand-crafted surface features. Our models present the first neural
Chinese discourse parser in the style of Chinese Discourse Treebank, showing
that our results hold cross-linguistically.


title: Operational approach to Bell inequalities: applications to qutrits

abstract:
  Bell inequalities can be studied both as constraints in the space of
probability distributions and as expectation values of multipartite operators.
The latter approach is particularly useful when considering outcomes as
eigenvalues of unitary operators. This brings the possibility of exploiting the
complex structure of the coefficients in the Bell operators. We investigate
this avenue of though in the known case of two outcomes, and find new Bell
inequalities for the cases of three outcomes and $n=3,4,5$ and $6$ parties. We
find their corresponding classical bounds and their maximum violation in the
case of qutrits. We further propose a novel way to generate Bell inequalities
based on a mapping from maximally entangled states to Bell operators and
produce examples for different outcomes and number of parties.


title:
An Active Set Algorithm for Nonlinear Optimization with Polyhedral
  Constraints

abstract:
  A polyhedral active set algorithm PASA is developed for solving a nonlinear
optimization problem whose feasible set is a polyhedron. Phase one of the
algorithm is the gradient projection method, while phase two is any algorithm
for solving a linearly constrained optimization problem. Rules are provided for
branching between the two phases. Global convergence to a stationary point is
established, while asymptotically PASA performs only phase two when either a
nondegeneracy assumption holds, or the active constraints are linearly
independent and a strong second-order sufficient optimality condition holds.


title: Asynchronous Multi-Agent Primal-Dual Optimization

abstract:
  We present a framework for asynchronously solving convex optimization
problems over networks of agents which are augmented by the presence of a
centralized cloud computer. This framework uses a Tikhonov-regularized
primal-dual approach in which the agents update the system's primal variables
and the cloud updates its dual variables. To minimize coordination requirements
placed upon the system, the times of communications and computations among the
agents are allowed to be arbitrary, provided they satisfy mild conditions.
Communications from the agents to the cloud are likewise carried out without
any coordination in their timing. However, we require that the cloud keep the
dual variable's value synchronized across the agents, and a counterexample is
provided that demonstrates that this level of synchrony is indeed necessary for
convergence. Convergence rate estimates are provided in both the primal and
dual spaces, and simulation results are presented that demonstrate the
operation and convergence of the proposed algorithm.


title:
CFO: Conditional Focused Neural Question Answering with Large-scale
  Knowledge Bases

abstract:
  How can we enable computers to automatically answer questions like "Who
created the character Harry Potter"? Carefully built knowledge bases provide
rich sources of facts. However, it remains a challenge to answer factoid
questions raised in natural language due to numerous expressions of one
question. In particular, we focus on the most common questions --- ones that
can be answered with a single fact in the knowledge base. We propose CFO, a
Conditional Focused neural-network-based approach to answering factoid
questions with knowledge bases. Our approach first zooms in a question to find
more probable candidate subject mentions, and infers the final answers with a
unified conditional probabilistic framework. Powered by deep recurrent neural
networks and neural embeddings, our proposed CFO achieves an accuracy of 75.7%
on a dataset of 108k questions - the largest public one to date. It outperforms
the current state of the art by an absolute margin of 11.8%.


title: Structurable equivalence relations

abstract:
  For a class $\mathcal K$ of countable relational structures, a countable
Borel equivalence relation $E$ is said to be $\mathcal K$-structurable if there
is a Borel way to put a structure in $\mathcal K$ on each $E$-equivalence
class. We study in this paper the global structure of the classes of $\mathcal
K$-structurable equivalence relations for various $\mathcal K$. We show that
$\mathcal K$-structurability interacts well with several kinds of Borel
homomorphisms and reductions commonly used in the classification of countable
Borel equivalence relations. We consider the poset of classes of $\mathcal
K$-structurable equivalence relations for various $\mathcal K$, under
inclusion, and show that it is a distributive lattice; this implies that the
Borel reducibility preordering among countable Borel equivalence relations
contains a large sublattice. Finally, we consider the effect on $\mathcal
K$-structurability of various model-theoretic properties of $\mathcal K$. In
particular, we characterize the $\mathcal K$ such that every $\mathcal
K$-structurable equivalence relation is smooth, answering a question of Marks.


title:
Interpreting tunneling time in circularly polarized strong-laser
  ionization

abstract:
  We propose a method to study the tunneling process by analyzing the
time-dependent ionization yield in circularly polarized laser. A numerical
calculation shows that for an atom exposed to a long laser pulse, if its
initial electronic state wave function is non-spherical symmetric, the delayed
phase shift of the ionization rate vs. the laser cycle period in real time in
the region close to the peak intensity of the laser pulse can be used to probe
the tunneling time. In this region, an obvious delay phase shift is observed,
showing the tunneling time is in order of tens of attoseconds. Further study
shows the atom has a longer tunneling time in the ionization under a shorter
wavelength laser pulse. In our method, a Wigner rotation technique is employed
to numerically solve the time-dependent Schr\"odinger equation of a
single-active-electron in a three dimensional spherical coordinate system.


title:
Modeling the effect of transient violations of the second law of
  thermodynamics on heat transfer in silicon nanowire

abstract:
  Violations of the second law of thermodynamics for small systems well below
the thermodynamic limit has already been experimentally observed. However, the
effects of such violations on experimentally measurable quantities have not
been studied in detail. Here we report the effect of transient violations,
i.e., spontaneous transfer of heat from cold to hot objects, on heat transfer
in silicon nanowire by modeling the violations as a Poisson process. Our
modeling and simulations show that it is increasingly difficult to cool down
the nanoscale objects to the bath temperature, there is a transition from power
law to exponential behavior, and the fluctuations have inverse square law
dependence on number of sites.


title:
A remark on equisingular approximations of quasi-plurisubharmonic
  functions

abstract:
  In this note, we will present global equisingular approximations of
quasi-plurisubharmonic functions with stable analytic pluripolar sets on
compact complex manifolds.


title: Enhanced current noise correlations in a Coulomb-Majorana device

abstract:
  Majorana bound states (MBSs) nested in a topological nanowire are predicted
to manifest nonlocal correlations in the presence of a finite energy splitting
between the MBSs. However, the signal of the nonlocal correlations has not yet
been detected in experiments. A possible reason is that the energy splitting is
too weak and seriously affected by many system parameters. Here we investigate
the charging energy induced nonlocal correlations in a hybrid device of MBSs
and quantum dots. The nanowire that hosts the MBSs is assumed in proximity to a
mesoscopic superconducting island with a finite charging energy. Each end of
the nanowire is coupled to one lead via a quantum dot with resonant levels.
With a floating superconducting island, the devices shows a negative
differential conductance and giant super-Poissonian shot noise, due to the
interplay between the nonlocality of the MBSs and dynamical Coulomb blockade
effect. When the island is strongly coupled to a bulk superconductor, the
current cross correlations at small lead chemical potentials are negative by
tuning the dot energy levels. In contrast, the cross correlation is always
positive in a non-Majorana setup. This difference may provide a signature for
the existence of the MBSs.


title: Intrinsic charm content of the nucleon and charmness-nucleon sigma term

abstract:
  In the extended chiral constituent quark model, the intrinsic $c \bar{c}$
content of the nucleon is investigated. The probabilities of the
quark-antiquark components in the nucleon wave functions are calculated by
taking the nucleon to be admixtures of three- and five-quark components, with
the relevant transitions handled {\it via} the $^{3}$P$_{0}$ mechanism.
Predictions for the probability of the $c \bar{c}$ in the nucleon wave function
and the charmness-nucleon sigma term are presented. Our numerical results turn
out to be consistent with the predictions from various other approaches
reported in the literature.


title: Reconfigurable Microwave Photonic Topological Insulator

abstract:
  Using full 3D finite element simulation and underlining Hamiltonian models,
we demonstrate reconfigurable photonic analogues of topological insulators on a
regular lattice of tunable posts in a re-entrant 3D lumped element type system.
The tunability allows dynamical {\it in-situ} change of media chirality and
other properties via alteration of the same parameter for all posts, and as a
result, great flexibility in choice of bulk/edge configurations. Additionally,
one way photon transport without an external magnetic field is demonstrated.
The ideas are illustrated by using both full finite element simulation as well
as simplified harmonic oscillator models. Dynamical reconfigurability of the
proposed systems paves the way to a new class of systems that can be employed
for random access, topological signal processing and sensing.


title:
Cherkis bow varieties and Coulomb branches of quiver gauge theories of
  affine type $A$

abstract:
  We show that Coulomb branches of quiver gauge theories of affine type $A$ are
Cherkis bow varieties, which have been introduced as ADHM type description of
moduli space of instantons on the Taub-NUT space equivariant under a cyclic
group action.


title: Memory-enhanced Decoder for Neural Machine Translation

abstract:
  We propose to enhance the RNN decoder in a neural machine translator (NMT)
with external memory, as a natural but powerful extension to the state in the
decoding RNN. This memory-enhanced RNN decoder is called \textsc{MemDec}. At
each time during decoding, \textsc{MemDec} will read from this memory and write
to this memory once, both with content-based addressing. Unlike the unbounded
memory in previous work\cite{RNNsearch} to store the representation of source
sentence, the memory in \textsc{MemDec} is a matrix with pre-determined size
designed to better capture the information important for the decoding process
at each time step. Our empirical study on Chinese-English translation shows
that it can improve by $4.8$ BLEU upon Groundhog and $5.3$ BLEU upon on Moses,
yielding the best performance achieved with the same training set.


title: Limit Theorems for Generalized Baker's Transformations

abstract:
  In this paper we study decay of correlations and limit theorems for
generalized baker's transformations. Our examples are piecewise non-uniformly
hyperbolic maps on the unit square that posses two spatially separated lines of
indifferent fixed points.
  We obtain sharp rates of mixing for Lipschitz functions on the unit square
and limit theorems for H\"older observables on the unit square. Some of our
limit theorems exhibit convergence to non-normal stable distributions for
H\"older observables. We observe that stable distributions with any skewness
parameter in the allowable range of $[-1,1]$ can be obtained as a limit and
derive an explicit relationship between the skewness parameter and the values
of the H\"older observable along the lines of indifferent fixed points.
  This paper is the first application of anisotropic Banach space methods and
operator renewal theory to generalized baker's transformations. Our decay of
correlations results recover the results of Bose and Murray. Our results on
limit theorems are new for generalized baker's transformations.


title: Heat kernels of non-symmetric jump processes: beyond the stable case

abstract:
  Let $J$ be the L\'evy density of a symmetric L\'evy process in $\mathbb{R}^d$
with its L\'evy exponent satisfying a weak lower scaling condition at infinity.
Consider the non-symmetric and non-local operator $$ {\mathcal
L}^{\kappa}f(x):= \lim_{\epsilon \downarrow 0} \int_{\{z \in \mathbb{R}^d:
|z|>\epsilon\}}(f(x+z)-f(x))\kappa(x,z)J(z)\, dz\, , $$ where $\kappa(x,z)$ is
a Borel measurable function on $\mathbb{R}^d\times \mathbb{R}^d$ satisfying
$0<\kappa_0\le \kappa(x,z)\le \kappa_1$, $\kappa(x,z)=\kappa(x,-z)$ and
$|\kappa(x,z)-\kappa(y,z)|\le \kappa_2|x-y|^{\beta}$ for some $\beta\in (0,
1)$. We construct the heat kernel $p^\kappa(t, x, y)$ of ${\mathcal L}^\kappa$,
establish its upper bound as well as its fractional derivative and gradient
estimates. Under an additional weak upper scaling condition at infinity, we
also establish a lower bound for the heat kernel $p^\kappa$.


title:
Incorporating Discrete Translation Lexicons into Neural Machine
  Translation

abstract:
  Neural machine translation (NMT) often makes mistakes in translating
low-frequency content words that are essential to understanding the meaning of
the sentence. We propose a method to alleviate this problem by augmenting NMT
systems with discrete translation lexicons that efficiently encode translations
of these low-frequency words. We describe a method to calculate the lexicon
probability of the next word in the translation candidate by using the
attention vector of the NMT model to select which source word lexical
probabilities the model should focus on. We test two methods to combine this
probability with the standard NMT probability: (1) using it as a bias, and (2)
linear interpolation. Experiments on two corpora show an improvement of 2.0-2.3
BLEU and 0.13-0.44 NIST score, and faster convergence time.


title:
iFogSim: A Toolkit for Modeling and Simulation of Resource Management
  Techniques in Internet of Things, Edge and Fog Computing Environments

abstract:
  Internet of Things (IoT) aims to bring every object (e.g. smart cameras,
wearable, environmental sensors, home appliances, and vehicles) online, hence
generating massive amounts of data that can overwhelm storage systems and data
analytics applications. Cloud computing offers services at the infrastructure
level that can scale to IoT storage and processing requirements. However, there
are applications such as health monitoring and emergency response that require
low latency, and delay caused by transferring data to the cloud and then back
to the application can seriously impact their performances. To overcome this
limitation, Fog computing paradigm has been proposed, where cloud services are
extended to the edge of the network to decrease the latency and network
congestion. To realize the full potential of Fog and IoT paradigms for
real-time analytics, several challenges need to be addressed. The first and
most critical problem is designing resource management techniques that
determine which modules of analytics applications are pushed to each edge
device to minimize the latency and maximize the throughput. To this end, we
need a evaluation platform that enables the quantification of performance of
resource management policies on an IoT or Fog computing infrastructure in a
repeatable manner. In this paper we propose a simulator, called iFogSim, to
model IoT and Fog environments and measure the impact of resource management
techniques in terms of latency, network congestion, energy consumption, and
cost. We describe two case studies to demonstrate modeling of an IoT
environment and comparison of resource management policies. Moreover,
scalability of the simulation toolkit in terms of RAM consumption and execution
time is verified under different circumstances.


title: A new type of sharp bounds for ratios of modified Bessel functions

abstract:
  The bounds for the ratios of first and second kind modified Bessel functions
of consecutive orders are important quantities appearing in a large number of
scientific applications. We obtain new bounds which are accurate in a large
region of parameters and which are shaper than previous bounds. The new bounds
are obtained by a qualitative analysis of the Riccati equation satisfied by
these ratios. A procedure is considered in which the bounds obtained from the
analysis of the Riccati equation are used to define a new function satisfying a
new Riccati equation which yields sharper bounds. Similar ideas can be applied
to other functions.


title: Learning deep structured network for weakly supervised change detection

abstract:
  Conventional change detection methods require a large number of images to
learn background models or depend on tedious pixel-level labeling by humans. In
this paper, we present a weakly supervised approach that needs only image-level
labels to simultaneously detect and localize changes in a pair of images. To
this end, we employ a deep neural network with DAG topology to learn patterns
of change from image-level labeled training data. On top of the initial CNN
activations, we define a CRF model to incorporate the local differences and
context with the dense connections between individual pixels. We apply a
constrained mean-field algorithm to estimate the pixel-level labels, and use
the estimated labels to update the parameters of the CNN in an iterative EM
framework. This enables imposing global constraints on the observed foreground
probability mass function. Our evaluations on four benchmark datasets
demonstrate superior detection and localization performance.


title: Heat switch effect in an antiferromagnetic insulator Co$_3$V$_2$O$_8$

abstract:
  We report a heat switch effect in single crystals of an antiferromagnet
Co$_3$V$_2$O$_8$, that is, the thermal conductivity ($\kappa$) can be changed
with magnetic field in an extremely large scale. Due to successive magnetic
phase transitions at 12--6 K, the zero-field $\kappa(T)$ displays a deep
minimum at 6.7 K and rather small magnitude at low temperatures. Both the
temperature and field dependencies of $\kappa$ demonstrate that the phonons are
strongly scattered at the regime of magnetic phase transitions. Magnetic field
can suppress magnetic scattering effect and significantly recover the phonon
thermal conductivity. In particular, a 14 T field along the $a$ axis increases
the $\kappa$ at 7.5 K up to 100 times. For $H \parallel c$, the magnitude of
$\kappa$ can be suppressed down to $\sim$ 8% at some field-induced transition
and can be enhanced up to 20 times at 14 T. The present results demonstrate
that it is possible to design a kind of heat switch in the family of magnetic
materials.


title:
Approximate nonparametric maximum likelihood inference for mixture
  models via convex optimization

abstract:
  Nonparametric maximum likelihood (NPML) for mixture models is a technique for
estimating mixing distributions that has a long and rich history in statistics
going back to the 1950s, and is closely related to empirical Bayes methods.
Historically, NPML-based methods have been considered to be relatively
impractical because of computational and theoretical obstacles. However, recent
work focusing on approximate NPML methods suggests that these methods may have
great promise for a variety of modern applications. Building on this recent
work, a class of flexible, scalable, and easy to implement approximate NPML
methods is studied for problems with multivariate mixing distributions.
Concrete guidance on implementing these methods is provided, with theoretical
and empirical support; topics covered include identifying the support set of
the mixing distribution, and comparing algorithms (across a variety of metrics)
for solving the simple convex optimization problem at the core of the
approximate NPML problem. Additionally, three diverse real data applications
are studied to illustrate the methods' performance: (i) A baseball data
analysis (a classical example for empirical Bayes methods), (ii)
high-dimensional microarray classification, and (iii) online prediction of
blood-glucose density for diabetes patients. Among other things, the empirical
results demonstrate the relative effectiveness of using multivariate (as
opposed to univariate) mixing distributions for NPML-based approaches.


title: Can neural machine translation do simultaneous translation?

abstract:
  We investigate the potential of attention-based neural machine translation in
simultaneous translation. We introduce a novel decoding algorithm, called
simultaneous greedy decoding, that allows an existing neural machine
translation model to begin translating before a full source sentence is
received. This approach is unique from previous works on simultaneous
translation in that segmentation and translation are done jointly to maximize
the translation quality and that translating each segment is strongly
conditioned on all the previous segments. This paper presents a first step
toward building a full simultaneous translation system based on neural machine
translation.


title: Riemann surface and quantization

abstract:
  This paper proposes an approach of the unified consideration of classical and
quantum mechanics from the standpoint of the complex analysis effects. It turns
out that quantization can be interpreted in terms of the Riemann surface
corresponding to the multivalent $\operatorname{Ln}\Psi $ function. A visual
interpretation of "trajectories" of the quantum system and of the Feynman's
path integral is presented. A magnetic dipole having a magnetic charge that
satisfies the Dirac quantization rule was obtained.


title:
Mean-field backward stochastic differential equations driven by
  fractional Brownian motion

abstract:
  In this paper, we focus on the mean-field backward stochastic differential
equations (BSDEs) driven by a fractional Brownian motion with Hurst parameter H
greater then 1/2. First, the existence and uniqueness of these equations are
established under Lipschitz condition. Then, a comparison theorem for such
mean-field BSDEs is obtained. Finally, as an application, we connect this
mean-field BSDE with a nonlocal partial differential equation (PDE).


title: Re-enabling high-speed caching for LSM-trees

abstract:
  LSM-tree has been widely used in cloud computing systems by Google, Facebook,
and Amazon, to achieve high performance for write-intensive workloads. However,
in LSM-tree, random key-value queries can experience long latency and low
throughput due to the interference from the compaction, a basic operation in
the algorithm, to caching. LSM-tree relies on frequent compaction operations to
merge data into a sorted structure. After a compaction, the original data are
reorganized and written to other locations on the disk. As a result, the cached
data are invalidated since their referencing addresses are changed, causing
serious performance degradations.
  We propose dLSM in order to re-enable high-speed caching during intensive
writes. dLSM is an LSM-tree with a compaction buffer on the disk, working as a
cushion to minimize the cache invalidation caused by compactions. The
compaction buffer maintains a series of snapshots of the frequently compacted
data, which represent a consistent view of the corresponding data in the
underlying LSM-tree. Being updated in a much lower rate than that of
compactions, data in the compaction buffer are almost stationary. In dLSM, an
object is referenced by the disk address of the corresponding block either in
the compaction buffer for frequently compacted data, or in the underlying
LSM-tree for infrequently compacted data. Thus, hot objects can be effectively
kept in the cache without harmful invalidations. With the help of a small
on-disk compaction buffer, dLSM achieves a high query performance by enabling
effective caching, while retaining all merits of LSM-tree for write-intensive
data processing. We have implemented dLSM based on LevelDB. Our evaluations
show that with a standard DRAM cache, dLSM can achieve 5--8x performance
improvement over LSM with the same cache on HDD storage.


title: Formal refinement of extended state machines

abstract:
  In a traditional formal development process, e.g. using the B method, the
informal user requirements are (manually) translated into a global abstract
formal specification. This translation is especially difficult to achieve. The
Event-B method was developed to incrementally and formally construct such a
specification using stepwise refinement. Each increment takes into account new
properties and system aspects. In this paper, we propose to couple a graphical
notation called Algebraic State-Transition Diagrams (ASTD) with an Event-B
specification in order to provide a better understanding of the software
behaviour. The dynamic behaviour is captured by the ASTD, which is based on
automata and process algebra operators, while the data model is described by
means of an Event-B specification. We propose a methodology to incrementally
refine such specification couplings, taking into account new refinement
relations and consistency conditions between the control specification and the
data specification. We compare the specifications obtained using each approach
for readability and proof complexity. The advantages and drawbacks of the
traditional approach and of our methodology are discussed. The whole process is
illustrated by a railway CBTC-like case study. Our approach is supported by
tools for translating ASTD's into B and Event-B into B.


title: Big Data Refinement

abstract:
  "Big data" has become a major area of research and associated funding, as
well as a focus of utopian thinking. In the still growing research community,
one of the favourite optimistic analogies for data processing is that of the
oil refinery, extracting the essence out of the raw data. Pessimists look for
their imagery to the other end of the petrol cycle, and talk about the "data
exhausts" of our society.
  Obviously, the refinement community knows how to do "refining". This paper
explores the extent to which notions of refinement and data in the formal
methods community relate to the core concepts in "big data". In particular, can
the data refinement paradigm can be used to explain aspects of big data
processing?


title: Unifying Theories of Mobile Channels

abstract:
  In this paper we present the denotational semantics for channel mobility in
the Unifying Theories of Programming (UTP) semantics framework. The basis for
the model is the UTP theory of reactive processes (precisely, the UTP semantics
for Communicating Sequential Processes (CSP)), which is slightly extended to
allow the mobility of channels: the set of actions in which a process is
authorised to participate, originally static or constant (set during the
process's definition), is now made dynamic or variable: it can change during
the process's execution. A channel is thus moved around by communicating it via
other channels and then allowing the receiving process to extend its alphabet
with the received channel. New healthiness conditions are stated to ensure an
appropriate use of mobile channels.


title: A logic for n-dimensional hierarchical refinement

abstract:
  Hierarchical transition systems provide a popular mathematical structure to
represent state-based software applications in which different layers of
abstraction are represented by inter-related state machines. The decomposition
of high level states into inner sub-states, and of their transitions into inner
sub-transitions is common refinement procedure adopted in a number of
specification formalisms.
  This paper introduces a hybrid modal logic for k-layered transition systems,
its first-order standard translation, a notion of bisimulation, and a modal
invariance result. Layered and hierarchical notions of refinement are also
discussed in this setting.


title: Program Derivation by Correctness Enhacements

abstract:
  Relative correctness is the property of a program to be more-correct than
another program with respect to a given specification. Among the many
properties of relative correctness, that which we found most intriguing is the
property that program P' refines program P if and only if P' is more-correct
than P with respect to any specification. This inspires us to reconsider
program derivation by successive refinements: each step of this process
mandates that we transform a program P into a program P' that refines P, i.e.
P' is more-correct than P with respect to any specification. This raises the
question: why should we want to make P' more-correct than P with respect to any
specification, when we only have to satisfy specification R? In this paper, we
discuss a process of program derivation that replaces traditional sequence of
refinement-based correctness-preserving transformations starting from
specification R by a sequence of relative correctness-based
correctness-enhancing transformations starting from abort.


title:
SCJ-Circus: a refinement-oriented formal notation for Safety-Critical
  Java

abstract:
  Safety-Critical Java (SCJ) is a version of Java whose goal is to support the
development of real-time, embedded, safety-critical software. In particular,
SCJ supports certification of such software by introducing abstractions that
enforce a simpler architecture, and simpler concurrency and memory models. In
this paper, we present SCJ-Circus, a refinement-oriented formal notation that
supports the specification and verification of low-level programming models
that include the new abstractions introduced by SCJ. SCJ-Circus is part of the
family of state-rich process algebra Circus, as such, SCJ-Circus includes the
Circus constructs for modelling sequential and concurrent behaviour, real-time
and object orientation. We present here the syntax and semantics of SCJ-Circus,
which is defined by mapping SCJ-Circus constructs to those of standard Circus.
This is based on an existing approach for modelling SCJ programs. We also
extend an existing Circus-based refinement strategy that targets SCJ programs
to account for the generation of SCJ-Circus models close to implementations in
SCJ.


title: Programming Language Features for Refinement

abstract:
  Algorithmic and data refinement are well studied topics that provide a
mathematically rigorous approach to gradually introducing details in the
implementation of software. Program refinements are performed in the context of
some programming language, but mainstream languages lack features for recording
the sequence of refinement steps in the program text. To experiment with the
combination of refinement, automated verification, and language design,
refinement features have been added to the verification-aware programming
language Dafny. This paper describes those features and reflects on some
initial usage thereof.


title:
Towards linking correctness conditions for concurrent objects and
  contextual trace refinement

abstract:
  Correctness conditions for concurrent objects describe how atomicity of an
abstract sequential object may be decomposed. Many different concurrent objects
and proof methods for them have been developed. However, arguments about
correctness are conducted with respect to an object in isolation. This is in
contrast to real-world practice, where concurrent objects are often implemented
as part of a programming language library (e.g., java.util.concurrent) and are
instantiated within a client program. A natural question to ask, then is: How
does a correctness condition for a concurrent object ensure correctness of a
client program that uses the concurrent object? This paper presents the main
issues that surround this question and provides some answers by linking
different correctness conditions with a form of trace refinement.


title: A Theory of Service Dependency

abstract:
  Service composition has become commonplace nowadays, in large part due to the
increased complexity of software and supporting networks. Composition can be of
many types, for instance sequential, prioritising, non-deterministic. However,
a fundamental feature of the services to be composed consists in their
dependencies with respect to each other. In this paper we propose a theory of
service dependency, modelled around a dependency operator in the Action Systems
formalism. We analyze its properties, composition behaviour, and refinement
conditions with accompanying examples.


title:
Evidences of the mismatch between industry and academy on modelling
  language quality evaluation

abstract:
  Quality is an implicit property of models and modelling languages by their
condition of engineering artifacts. However, the quality property is affected
by the diversity of conceptions around the model-driven paradigm. In this
document is presented a report of quality issues on modelling languages and
models. These issues result from an analysis about quality evidences obtained
from industrial and academic/scientific contexts.


title: Minimal curvature-constrained networks

abstract:
  This paper introduces an exact algorithm for the construction of a shortest
curvature-constrained network interconnecting a given set of directed points in
the plane and an iterative method for doing so in 3D space. Such a network will
be referred to as a minimum Dubins network, since its edges are Dubins paths
(or slight variants thereof). The problem of constructing a minimum Dubins
network appears in the context of underground mining optimisation, where the
aim is to construct a least-cost network of tunnels navigable by trucks with a
minimum turning radius. The Dubins network problem is similar to the Steiner
tree problem, except that the terminals are directed and there is a curvature
constraint. We propose the minimum curvature-constrained Steiner point
algorithm for determining the optimal location of the Steiner point in a
3-terminal network. We show that when two terminals are fixed and the third
varied, the Steiner point traces out a lima\c{c}on.


title:
The Effect of Perturbations of Frames and Fusion Frames on Their
  Redundancies

abstract:
  An interesting question about the perturbed sequences is: when do they
inherit the properties of the original one? An elegant relation between frames
(fusion frames) and their perturbations is the relation of their redundancies.
  In this paper, we investigate these relationships. Also, we express the
redundancy of frames (fusion frames) in terms of the cosine angle between some
subspaces.


title: Lefschetz properties of balanced 3-polytopes

abstract:
  In this paper, we study Lefschetz properties of Artinian reductions of
Stanley-Reisner rings of balanced simplicial $3$-polytopes. A
$(d-1)$-dimensional simplicial complex is said to be balanced if its graph is
$d$-colorable. If a simplicial complex is balanced, then its Stanley-Reisner
ring has a special system of parameters induced by the coloring. We prove that
the Artinian reduction of the Stanley-Reisner ring of a balanced simplicial
$3$-polytope with respect to this special system of parameters has the strong
Lefschetz property if the characteristic of the base field is not two or three.
Moreover, we characterize $(2,1)$-balanced simplicial polytopes, i.e.,
polytopes with exactly one red vertex and two blue vertices in each facet, such
that an analogous property holds. In fact, we show that this is the case if and
only if the induced graph on the blue vertices satisfies a Laman-type
combinatorial condition.


title:
The bulk, surface and corner free energies of the square lattice Ising
  model

abstract:
  We use Kaufman's spinor method to calculate the bulk, surface and corner free
energies $f_b, f_s, f_s', f_c$ of the anisotropic square lattice zero-field
Ising model for the ordered ferromagnetic case. For $f_b, f_s, f'_s$ our
results of course agree with the early work of Onsager, McCoy and Wu. We also
find agreement with the conjectures made by Vernier and Jacobsen (VJ) for the
isotropic case. We note that the corner free energy $f_c$ depends only on the
elliptic modulus $k$ that enters the working, and not on the argument $v$,
which means that VJ's conjecture applies for the full anisotropic model. The
only aspect of this paper that is new is the actual derivation of $f_c$, but by
reporting all four free energies together we can see interesting structures
linking them.


title:
Radiative Transfer Model of Dust Attenuation Curves in Clumpy, Galactic
  Environments

abstract:
  The attenuation of starlight by dust in galactic environments is investigated
through models of radiative transfer in a spherical, clumpy ISM. Extinction
properties for MW, LMC, and SMC dust types are considered. It is illustrated
that the attenuation curves are primarily determined by the wavelength
dependence of absorption rather than by the underlying extinction
(absorption+scattering) curve. Attenuation curves consistent with the "Calzetti
attenuation curve" are found by assuming the silicate-carbonaceous dust model
for the MW, but with the 2175A absorption bump suppressed or absent. The
discrepancy between our results and previous work that claimed the SMC-type
dust to be the most likely origin of the Calzetti curve is ascribed to the
difference in adopted albedos; this study uses the theoretically calculated
albedos whereas the previous ones adopted empirically derived albedos from
observations of reflection nebulae. It is also found that the model attenuation
curves calculated with the MW dust are well represented by a modified Calzetti
curve with a varying slope and UV bump strength. The strong correlation between
the slope and UV bump strength, with steeper curves having stronger bumps, as
found in star-forming galaxies at 0.5<z<2.0, is well reproduced by our models
if the abundance of the UV bump carriers or PAHs is assumed to be 30% or 40% of
that of the MW-dust. The trend is explained by radiative transfer effects which
lead to shallower attenuation curves with weaker UV bumps as the ISM is more
clumpy and dustier. We also argue that at least some of the IUE local starburst
galaxies may have a UV bump feature in their attenuation curves, albeit much
weaker than that of the MW extinction curve.


title:
Hand Action Detection from Ego-centric Depth Sequences with
  Error-correcting Hough Transform

abstract:
  Detecting hand actions from ego-centric depth sequences is a practically
challenging problem, owing mostly to the complex and dexterous nature of hand
articulations as well as non-stationary camera motion. We address this problem
via a Hough transform based approach coupled with a discriminatively learned
error-correcting component to tackle the well known issue of incorrect votes
from the Hough transform. In this framework, local parts vote collectively for
the start $\&$ end positions of each action over time. We also construct an
in-house annotated dataset of 300 long videos, containing 3,177 single-action
subsequences over 16 action classes collected from 26 individuals. Our system
is empirically evaluated on this real-life dataset for both the action
recognition and detection tasks, and is shown to produce satisfactory results.
To facilitate reproduction, the new dataset and our implementation are also
provided online.


title: Human vs. Computer Go: Review and Prospect

abstract:
  The Google DeepMind challenge match in March 2016 was a historic achievement
for computer Go development. This article discusses the development of
computational intelligence (CI) and its relative strength in comparison with
human intelligence for the game of Go. We first summarize the milestones
achieved for computer Go from 1998 to 2016. Then, the computer Go programs that
have participated in previous IEEE CIS competitions as well as methods and
techniques used in AlphaGo are briefly introduced. Commentaries from three
high-level professional Go players on the five AlphaGo versus Lee Sedol games
are also included. We conclude that AlphaGo beating Lee Sedol is a huge
achievement in artificial intelligence (AI) based largely on CI methods. In the
future, powerful computer Go programs such as AlphaGo are expected to be
instrumental in promoting Go education and AI real-world applications.


title:
User Cooperation for Enhanced Throughput Fairness in Wireless Powered
  Communication Networks

abstract:
  This paper studies a novel user cooperation method in a wireless powered
communication network (WPCN), where a pair of distributed terminal users first
harvest wireless energy broadcasted by one energy node (EN) and then use the
harvested energy to transmit information cooperatively to a destination node
(DN). In particular, the two cooperating users exchange their independent
information with each other to form a virtual antenna array and transmit
jointly to the DN. By allowing each user to allocate part of its harvested
energy to transmit the other's information, the proposed cooperation can
effectively mitigate the user unfairness problem in WPCNs, where a user may
suffer from very low data rate due to the poor energy harvesting performance
and high data transmission consumptions. We derive the maximum common
throughput achieved by the cooperation scheme through optimizing the time
allocation on wireless energy transfer, user message exchange, and joint
information transmissions. Through comparing with some representative benchmark
schemes, our results demonstrate the effectiveness of the proposed user
cooperation in enhancing the throughput performance under different setups.


title: Galois sets of connected components and Weil restriction

abstract:
  Let $k$ be a field, $A$ a finite $k$-algebra and $X$ a smooth $A$-scheme. We
describe the Galois set of connected components of the Weil restriction
$\Re_{A/k}(X)$ in terms of the sets of connected components of the geometric
fibers of $X$.


title:
Optimal targeting of nonlinear chaotic systems using a novel
  evolutionary computing strategy

abstract:
  Control of chaotic systems to given targets is a subject of substantial and
well-developed research issue in nonlinear science, which can be formulated as
a class of multi-modal constrained numerical optimization problem with
multi-dimensional decision variables. This investigation elucidates the
feasibility of applying a novel population-based metaheuristics labelled here
as Teaching-learning-based optimization to direct the orbits of discrete
chaotic dynamical systems towards the desired target region. Several
consecutive control steps of small bounded perturbations are made in the
Teaching-learning-based optimization strategy to direct the chaotic series
towards the optimal neighborhood of the desired target rapidly, where a
conventional controller is effective for chaos control. Working with the
dynamics of the well-known Henon as well as Ushio discrete chaotic systems, we
assess the effectiveness and efficiency of the Teaching-learning-based
optimization based optimal control technique, meanwhile the impacts of the core
parameters on performances are also discussed. Furthermore, possible
engineering applications of directing chaotic orbits are discussed.


title:
Einstein-Podolsky-Rosen Entanglement of Narrowband Photons from Cold
  Atoms

abstract:
  Einstein-Podolsky-Rosen (EPR) entanglement introduced in 1935 deals with two
particles that are entangled in their positions and momenta. Here we report the
first experimental demonstration of EPR position-momentum entanglement of
narrowband photon pairs generated from cold atoms. By using two-photon quantum
ghost imaging and ghost interference, we demonstrate explicitly that the
narrowband photon pairs violate the separability criterion, confirming EPR
entanglement. We further demonstrate continuous variable EPR steering for
positions and momenta of the two photons. Our new source of EPR-entangled
narrowband photons is expected to play an essential role in
spatially-multiplexed quantum information processing, such as, storage of
quantum correlated images, quantum interface involving hyper-entangled photons,
etc.


title:
Solving the Dynamic Correlation Problem of the
  Susceptible-Infected-Susceptible Model on Networks

abstract:
  The Susceptible-Infected-Susceptible model is a canonical model for emerging
disease outbreaks. Such outbreaks are naturally modeled as taking place on
networks. A theoretical challenge in network epidemiology is the dynamic
correlations coming from that if one node is occupied, or infected (for disease
spreading models), then its neighbors are likely to be occupied. By combining
two theoretical approaches---the heterogeneous mean-field theory and the
effective degree method---we are able to include these correlations in an
analytical solution of the SIS model. We derive accurate expressions for the
average prevalence (fraction of infected) and epidemic threshold. We also
discuss how to generalize the approach to a larger class of stochastic
population models.


title:
Spurious Small-Scale Structure & Discreteness-Driven Relaxation in
  Cosmological Simulations

abstract:
  There is strong evidence that cosmological N-body simulations dominated by
Warm Dark Matter (WDM) contain spurious or unphysical haloes, most readily
apparent as regularly spaced low-mass haloes strung along filaments. We show
that spurious haloes are a feature of traditional N-body simulations of
cosmological structure formation models, including WDM and Cold Dark Matter
(CDM) models, in which gravitational collapse proceeds in an initially
anisotropic fashion, and arises naturally as a consequence of
discreteness-driven relaxation. We demonstrate this using controlled N-body
simulations of plane-symmetric collapse and show that spurious haloes are
seeded at shell crossing by localised velocity perturbations induced by the
discrete nature of the density field, and that their characteristic separation
should be approximately the mean inter-particle separation of the N-body
simulation, which is fixed by the mass resolution within the volume. Using
cosmological N-body simulations in which particles are split into two
collisionless components of fixed mass ratio, we find that the spatial
distribution of the two components show signatures of discreteness-driven
relaxation in their spatial distribution on both large and small scales.
Adopting a spline kernel gravitational softening that is of order the comoving
mean inter-particle separation helps to suppress the effect of
discreteness-driven relaxation, but cannot eliminate it completely. These
results provide further motivation for recent developments of new algorithms,
which include, for example, revisions of the traditional N-body approach by
means of spatially adaptive anistropric gravitational softenings or explicit
solutions for the evolution of dark matter in phase space.


title: Emergence of F(R) gravity-analogue due to defects in graphene

abstract:
  We show that the defects of graphene, which lead to the non-equality between
positive curvature of fermions with anti-parallel spins and negative curvature
of fermions with parallel spins, imply an emergence of F(R) gravity. By
increasing the number of atoms at each defect, the order of scalar curvature
increases and the shape of F(R) gravity changes. This gravity has a direct
relation with energy-momentum tensor and leads to motion of electrons in a
special path and hence producing superconductivity. Also, for some special
angles, parallel spins become close to each other and repel to each other. In
that condition, the shape of F(R) gravity changes and electrons can't continue
to move in an initial path and return. Consequently, superconductivity
disappears and one new conductivity appears in opposite direction.


title: Coarse Lipschitz embeddings of James spaces

abstract:
  We prove that, for $1 < p \neq q < \infty$, there does not exist any coarse
Lipschitz embedding between the two James spaces $J_p$ and $J_q$, and that, for
$1 < p < q < \infty$ and $1 < r < \infty$ such that $r \notin \{p,q\}$, $J_r$
does not coarse Lipschitz embed into $J_p \oplus J_q$.


title:
Sorting out symptoms: design and evaluation of the 'babylon check'
  automated triage system

abstract:
  Prior to seeking professional medical care it is increasingly common for
patients to use online resources such as automated symptom checkers. Many such
systems attempt to provide a differential diagnosis based on the symptoms
elucidated from the user, which may lead to anxiety if life or limb-threatening
conditions are part of the list, a phenomenon termed 'cyberchondria' [1].
Systems that provide advice on where to seek help, rather than a diagnosis, are
equally popular, and in our view provide the most useful information. In this
technical report we describe how such a triage system can be modelled
computationally, how medical insights can be translated into triage flows, and
how such systems can be validated and tested. We present babylon check, our
commercially deployed automated triage system, as a case study, and illustrate
its performance in a large, semi-naturalistic deployment study.


title:
Adaptive Quantization Matrices for HD and UHD Display Resolutions in
  Scalable HEVC

abstract:
  HEVC contains an option to enable custom quantization matrices, which are
designed based on the Human Visual System and a 2D Contrast Sensitivity
Function. Visual Display Units, capable of displaying video data at High
Definition and Ultra HD display resolutions, are frequently utilized on a
global scale. Video compression artifacts that are present due to high levels
of quantization, which are typically inconspicuous in low display resolution
environments, are clearly visible on HD and UHD video data and VDUs. The
default QM technique in HEVC does not take into account the video data
resolution, nor does it take into consideration the associated display
resolution of a VDU to determine the appropriate levels of quantization
required to reduce unwanted video compression artifacts. Based on this fact, we
propose a novel, adaptive quantization matrix technique for the HEVC standard,
including Scalable HEVC. Our technique, which is based on a refinement of the
current HVS-CSF QM approach in HEVC, takes into consideration the display
resolution of the target VDU for the purpose of minimizing video compression
artifacts. In SHVC SHM 9.0, and compared with anchors, the proposed technique
yields important quality and coding improvements for the Random Access
configuration, with a maximum of 56.5% luma BD-Rate reductions in the
enhancement layer. Furthermore, compared with the default QMs and the Sony QMs,
our method yields encoding time reductions of 0.75% and 1.19%, respectively.


title: Spin polarisation by current

abstract:
  This is an overview of current-induced spin polarization in gyrotropic
semiconductor nanostructures. Such a spin polarization as response to a charge
current may be classified as the inverse of the spin-galvanic effect, and
sometimes is called as magneto-electrical effect or Edelstein
(Rashba-Edelstein) effect. Apart from reviewing the experimental status of
affairs, we have provided a detailed theoretical description of both effects in
terms of a phenomenological model of spin-dependent relaxation processes, and
an alternative theoretical approach based on the quasi-classical Boltzmann
equation.


title: Three notes on Ser's and Hasse's representations for the zeta-functions

abstract:
  This paper is devoted to Ser's and Hasse's series representations for the
zeta-functions, as well as to several closely related results. The notes
concerning Ser's and Hasse's representations are given as theorems, while the
related expansions are given either as separate theorems or as formulae inside
the remarks and corollaries. In the first theorem, we show that the famous
Hasse's series for the zeta-function, obtained in 1930 and named after the
German mathematician Helmut Hasse, is equivalent to an earlier expression given
by a little-known French mathematician Joseph Ser in 1926. In the second
theorem, we derive a similar series representation for the zeta-function
involving the Cauchy numbers of the second kind. In the third theorem, with the
aid of some special polynomials, we generalize the previous results to the
Hurwitz zeta-function. In the fourth theorem, we obtain a similar series with
Gregory's coefficients of higher order. In the fifth theorem, we extend the
results of the third theorem to a class of Dirichlet series. As a consequence,
we obtain several globally convergent series for the zeta-functions. We also
show that Hasse's series may be obtained much more easily by using the theory
of finite differences, and we demonstrate that there exist numerous series of
the same nature. In the sixth theorem, we show that Hasse's series is a simple
particular case of a more general class of series involving the Stirling
numbers of the first kind. All the expansions derived in the paper lead, in
turn, to the series expansions for the Stieltjes constants, including new
series with rational terms for Euler's constant, for the logarithm of the
gamma-function, for the digamma and trigamma functions. Finally, in the
Appendix, we prove an interesting integral representation for the Bernoulli
polynomials of the second kind, formerly known as the Fontana-Bessel
polynomials.


title:
On the "usual" misunderstandings between econophysics and finance: some
  clarifications on modelling approaches and efficient market hypothesis

abstract:
  In line with the recent research and debates about econophysics and financial
economics, this article discusses on usual misunderstandings between the two
disciplines in terms of modelling and basic hypotheses. In the literature
devoted to econophysics, the methodology used by financial economists is
frequently considered as a top-down approach (starting from a priori "first
principles") while econophysicists rather present themselves as scholars
working with a (empirical data prone) bottom-up approach. Although this dualist
perspective is very common in the econophysics literature, this paper claims
that the distinction is very confusing and does not permit to reveal the
essence of the differences between finance and econophysics. The distinction
between these two fields is mainly investigated here through the lens of the
Efficient Market Hypothesis in order to show that, in substance, econophysics
and financial economics tend to have a similar approach implying that the
misunderstanding between these two fields at the modelling level can therefore
be overstepped.


title: Global generation and very ampleness for adjoint linear series

abstract:
  Let $X$ be a smooth projective variety over an algebraically closed field
$\mathbb{K}$ with arbitrary characteristic. Suppose $L$ is an ample and
globally generated line bundle. By Castelnuovo--Mumford regularity, we show
that $K_X \otimes L^{\otimes \dim X} \otimes A$ is globally generated and $K_X
\otimes L^{\otimes (\dim X+1)} \otimes A$ is very ample, provided the line
bundle $A$ is nef but not numerically trivial. On complex projective varieties,
by investigating Kawamata-Viehweg-Nadel type vanishing theorems for vector
bundles, we also obtain the global generation for adjoint vector bundles. In
particular, for a holomorphic submersion $f:X\longrightarrow Y$ with $L$ ample
and globally generated, and $A$ nef but not numerically trivial, we prove the
global generation of $ f_*(K_{X/Y})^{\otimes s}\otimes K_Y \otimes L^{\otimes
\dim Y} \otimes A$ for any positive integer $s$.


title:
Fermi level position, Coulomb gap, and Dresselhaus splitting in
  (Ga,Mn)As

abstract:
  Carrier-induced nature of ferromagnetism in a ferromagnetic semiconductor,
(Ga,Mn)As, offers a great opportunity to observe novel spin-related phenomena
as well as to demonstrate new functionalities of spintronic devices. Here, we
report on low-temperature angle-resolved photoemission studies of the valence
band in this model compound. By a direct determination of the distance of the
split-off band to the Fermi energy EF, we conclude that EF is located within
the heavy/light hole band. However, the bands are strongly perturbed by
disorder and disorder-induced carrier correlations that lead to the Coulomb gap
at EF, which we resolve experimentally in a series of samples, and show that
its depth and width enlarge when the Curie temperature decreases. Furthermore,
we have detected surprising linear magnetic dichroism in photoemission spectra
of the split-off band. By a quantitative theoretical analysis we demonstrate
that it arises from the Dresselhaus-type spin-orbit term in zinc-blende
crystals. The spectroscopic access to the magnitude of such asymmetric part of
spin-orbit coupling is worthwhile, as they account for spin-orbit torque in
spintronic devices of ferromagnets without inversion symmetry.


title:
Einstein-Maxwell-Dilatonic phantom black holes: Thermodynamics and
  geometrothermodynamics

abstract:
  We use the Legendre invariant formalism of geometrothermodynamics to
investigate the geometric properties of the equilibrium space of a spherically
symmetric phantom black hole with electric charge and dilaton. We find that at
certain points of the equilibrium space, the thermodynamic curvature is
characterized by the presence of singularities that are interpreted as phase
transitions. We also investigate the phase transition structure by using the
standard approach of black hole thermodynamics based upon the analysis of the
heat capacity and response functions. We show compatibility between the two
approaches. In addition, a new type of phase transition is found which is due
to the presence of phantom energy and corresponds to a transition between black
hole states with different stability properties.


title:
Departure of high temperature iron lines from the equilibrium state in
  flaring solar plasmas

abstract:
  The aim of this study is to clarify if the assumption of ionization
equilibrium and a Maxwellian electron energy distribution is valid in flaring
solar plasmas. We analyze the 2014 December 20 X1.8 flare, in which the
\ion{Fe}{xxi} 187~\AA, \ion{Fe}{xxii} 253~\AA, \ion{Fe}{xxiii} 263~\AA\ and
\ion{Fe}{xxiv} 255~\AA\ emission lines were simultaneously observed by the EUV
Imaging Spectrometer onboard the Hinode satellite. Intensity ratios among these
high temperature Fe lines are compared and departures from isothermal
conditions and ionization equilibrium examined. Temperatures derived from
intensity ratios involving these four lines show significant discrepancies at
the flare footpoints in the impulsive phase, and at the looptop in the gradual
phase. Among these, the temperature derived from the
\ion{Fe}{xxii}/\ion{Fe}{xxiv} intensity ratio is the lowest, which cannot be
explained if we assume a Maxwellian electron distribution and ionization
equilibrium, even in the case of a multi-thermal structure. This result
suggests that the assumption of ionization equilibrium and/or a Maxwellian
electron energy distribution can be violated in evaporating solar plasma around
10~MK.


title:
Microbubbles and microparticles are not faithful tracers of turbulent
  acceleration

abstract:
  We report on the Lagrangian statistics of acceleration of small
(sub-Kolmogorov) bubbles and tracer particles with Stokes number St << 1 in
turbulent flow. At decreasing Reynolds number, the bubble accelerations show
deviations from that of tracer particles, i.e. they deviate from the
Heisenberg-Yaglom prediction and show a quicker decorrelation despite their
small size and minute St. Using direct numerical simulations, we show that
these effects arise due the drift of these particles through the turbulent
flow. We theoretically predict this gravity-driven effect for developed
isotropic turbulence, with the ratio of Stokes to Froude number or equivalently
the particle drift-velocity governing the enhancement of acceleration variance
and the reductions in correlation time and intermittency. Our predictions are
in good agreement with experimental and numerical results. The present findings
are relevant to a range of scenarios encompassing tiny bubbles and droplets
that drift through the turbulent oceans and the atmosphere. They also question
the common usage of micro-bubbles and micro-droplets as tracers in turbulence
research.


title:
Control of Exciton Valley Coherence in Transition Metal Dichalcogenide
  Monolayers

abstract:
  The direct gap interband transitions in transition metal dichalcogenides
monolayers are governed by chiral optical selection rules. Determined by laser
helicity, optical transitions in either the $K^+$ or $K^-$ valley in momentum
space are induced. Linearly polarized laser excitation prepares a coherent
superposition of valley states. Here we demonstrate the control of the exciton
valley coherence in monolayer WSe2 by tuning the applied magnetic field
perpendicular to the monolayer plane. We show rotation of this coherent
superposition of valley states by angles as large as 30 degrees in applied
fields up to 9 T. This exciton valley coherence control on ps time scale could
be an important step towards complete control of qubits based on the valley
degree of freedom.


title: Bolidozor - Distributed radio meteor detection system

abstract:
  Most of the meteor radioastronomical radars are backscatter radars which
cover only a small area of the atmosphere. Therefore a daytime meteor flux
models are based on sparse data collected by only a few radar systems. To solve
this issue, a radar system with a wide coverage is required. We present a new
approach of open-source multi-static radio meteor detection system which could
be distributed over a large area. This feature allows us to detect meteor
events taking place over a larger area as well and gather more uniform data
about meteor flux and possibly about meteor trajectories.


title:
All-stages-implicit and strong-stability-preserving implicit-explicit
  Runge-Kutta time discretization schemes for hyperbolic systems with stiff
  relaxation terms

abstract:
  We construct eight implicit-explicit (IMEX) Runge-Kutta (RK) schemes up to
third order of the type in which all stages are implicit so that they can be
used in the zero relaxation limit in a unified and convenient manner. These
all-stages-implicit (ASI) schemes attain the strong-stability-preserving (SSP)
property in the limiting case, and two are SSP for not only the explicit part
but also the implicit part and the entire IMEX scheme. Three schemes can
completely recover to the designed accuracy order in two sides of the
relaxation parameter for both equilibrium and non-equilibrium initial
conditions. Two schemes converge nearly uniformly for equilibrium cases. These
ASI schemes can be used for hyperbolic systems with stiff relaxation terms or
differential equations with some type constraints.


title:
A simple multithreaded implementation of the EM algorithm for mixture
  models

abstract:
  Finite mixture models have been widely used for the modelling and analysis of
data from heterogeneous populations. Maximum likelihood estimation of the
parameters is typically carried out via the Expectation-Maximization (EM)
algorithm. The complexity of the implementation of the algorithm depends on the
parametric distribution that is adopted as the component densities of the
mixture model. In the case of the skew normal and skew t-distributions, for
example, the E-step would involve complicated expressions that are
computationally expensive to evaluate. This can become quite time-consuming for
large and/or high-dimensional datasets. In this paper, we develop a
multithreaded version of the EM algorithm for the fitting of finite mixture
models. Due to the structure of the algorithm for these models, the E- and
M-steps can be easily reformulated to be executed in parallel across multiple
threads to take advantage of the processing power available in modern-day
multicore machines. Our approach is simple and easy to implement, requiring
only small changes to standard code. To illustrate the approach, we focus on a
fairly general mixture model that includes as special or limiting cases some of
the most commonly used mixture models including the normal, t-, skew normal,
and skew t-mixture models.


title:
From Constrained Delaunay Triangulations to Roadmap Graphs with
  Arbitrary Clearance

abstract:
  This work studies path planning in two-dimensional space, in the presence of
polygonal obstacles. We specifically address the problem of building a roadmap
graph, that is, an abstract representation of all the paths that can
potentially be followed around a given set of obstacles. Our solution consists
in an original refinement algorithm for constrained Delaunay triangulations,
aimed at generating a roadmap graph suited for planning paths with arbitrary
clearance. In other words, a minimum distance to the obstacles can be
specified, and the graph does not have to be recomputed if this distance is
modified. Compared to other solutions, our approach has the advantage of being
simpler, as well as significantly more efficient.


title: Ramsey properties of nonlinear Diophantine equations

abstract:
  We prove general sufficient and necessary conditions for the partition
regularity of Diophantine equations, which extend the classic Rado's Theorem by
covering large classes of nonlinear equations. Sufficient conditions are
obtained by exploiting algebraic properties in the space of ultrafilters betaN,
grounding on combinatorial properties of positive density sets and IP sets.
Necessary conditions are proved by a new technique in nonstandard analysis,
based on the use of the relation of u-equivalence for the hypernatural numbers
*N.


title: Applications of small scale quantum ergodicity in nodal sets

abstract:
  The goal of this article is to draw new applications of small scale quantum
ergodicity in nodal sets of eigenfunctions. We show that if quantum ergodicity
holds on balls of shrinking radius $r(\lambda) \to 0$, then one can achieve
improvements on the recent upper bounds of Logunov and Logunov-Malinnikova on
the size of nodal sets, according to a certain power of $r(\lambda)$. We also
show that the order of vanishing results of Donnelly-Fefferman and Dong can be
improved. Since by the results of Han and Hezari-Rivi\`ere small scale QE holds
on negatively curved manifolds at logarithmically shrinking rates, we get
logarithmic improvements on such manifolds for the above measurements of
eigenfunctions. We also get $o(1)$ improvements for manifolds with ergodic
geodesic flows. Our results work for a full density subsequence of any given
orthonormal basis of eigenfunctions.


title: A note on the Neumann eigenvalues of the biharmonic operator

abstract:
  We study the dependence of the eigenvalues of the biharmonic operator subject
to Neumann boundary conditions on the Poisson's ratio. In particular, we prove
that the Neumann eigenvalues are Lipschitz continuous with respect to
$\sigma\in [0,1[$ and that all the Neumann eigenvalues tend to zero as
$\sigma\rightarrow 1^-$. Moreover, we show that the Neumann problem defined by
setting $\sigma=1$ admits a sequence of positive eigenvalues of finite
multiplicity which are not limiting points for the Neumann eigenvalues with
$\sigma\in[0,1[$ as $\sigma\rightarrow 1^-$, and which coincide with the
Dirichlet eigenvalues of the biharmonic operator.


title: Frobenius actions on local cohomology modules and deformation

abstract:
  Let $(R,m)$ be a Noetherian local ring of characteristic $p>0$. We introduce
and study $F$-full and $F$-anti-nilpotent singularities, both are defined in
terms of the Frobenius actions on the local cohomology modules of $R$ supported
at the maximal ideal. We prove that if $R/(x)$ is $F$-full or
$F$-anti-nilpotent for a nonzerodivisor $x\in R$, then so is $R$. We use these
results to obtain new cases on the deformation of $F$-injectivity.


title: Domination of the rectangular queen's graph

abstract:
  The queen's graph $Q_{m \times n}$ has the squares of the $m \times n$
chessboard as its vertices; two squares are adjacent if they are in the same
row, column, or diagonal of the board. A set $D$ of squares of $Q_{m \times n}$
is a dominating set for $Q_{m \times n}$ if every square of $Q_{m \times n}$ is
either in $D$ or adjacent to a square in $D$. The minimum size of a dominating
set of $Q_{m \times n}$ is the domination number, denoted by $\gamma(Q_{m
\times n})$. Values of $\gamma(Q_{m \times n}), \, 4 \leq m \leq n \leq 18, \,$
are given here, in each case with a file of minimum dominating sets (often all
of them, up to symmetry) in an online appendix at
https://www.combinatorics.org/ojs/index.php/eljc/article/view/v26i4p45/HTML. In
these ranges for $m$ and $n$, monotonicity fails once: $\gamma(Q_{8 \times 11})
= 6 > 5 = \gamma(Q_{9 \times 11}) = \gamma(Q_{10 \times 11}) = \gamma(Q_{11
\times 11})$. Lower bounds on $\gamma(Q_{m \times n})$ are given. In
particular, if $m \leq n$ then $\gamma(Q_{m \times n}) \geq \min \{ m, \lceil
(m+n-2)/4 \rceil \}$. A set of squares is independent if no two of its squares
are adjacent. The minimum size of an independent dominating set of $Q_{m \times
n}$ is the independent domination number, denoted by $i(Q_{m \times n})$.
Values of $i(Q_{m \times n}), \, 4 \leq m \leq n \leq 18, \,$ are given here,
in each case with some minimum dominating sets. In these ranges for $m$ and
$n$, monotonicity fails twice: $i(Q_{8 \times 11}) = 6 > 5 = i(Q_{9 \times 11})
= i(Q_{10 \times 11}) = i(Q_{11 \times 11})$, and $i(Q_{11 \times 18}) = 9 > 8
= i(Q_{12 \times 18})$.


title: Tree-hierarchy of DNA and distribution of Holliday junctions

abstract:
  We define a DNA as a sequence of $\pm 1$'s and embed it on a path of Cayley
tree. Using group representation of the Cayley tree, we give a hierarchy of a
countable set of DNAs each of which 'lives' on the same Cayley tree. This
hierarchy has property that each vertex of the Cayley tree belongs only to one
of DNA. Then we give a model (energy, Hamiltonian) of this set of DNAs by an
analogue of Ising model with three spin values (considered as DNA base pairs)
on a set of admissible configurations. To study thermodynamic properties of the
model of DNAs we describe corresponding translation invariant Gibbs measures
(TIGM) of the model on the Cayley tree of order two. We show that there is a
critical temperature $T_{\rm c}$ such that (i) if temperature $T>T_{\rm c}$
then there exists unique TIGM; (ii) if $T=T_{\rm c}$ then there are two TIGMs;
(iii) if $T<T_{\rm c}$ then there are three TIGMs. Each such measure describes
a phase of the set of DNAs. We use these results to study distributions of
Holliday junctions and branches of DNAs. In case of very high and very low
temperatures we give stationary distributions and typical configurations of the
Holliday junctions.


title:
Parallax and orbital effects in astrometric microlensing with binary
  sources

abstract:
  In gravitational microlensing, binary systems may act as lenses or sources.
Identifying lens binarity is generally easy especially in events characterized
by caustic crossing since the resulting light curve exhibits strong deviations
from smooth single-lensing light curve. On the contrary, light curves with
minor deviations from a Paczy\'nski behaviour do not allow one to identify the
source binarity. A consequence of the gravitational microlensing is the shift
of the position of the multiple image centroid with respect to the source star
location - the so called astrometric microlensing signal. When the astrometric
signal is considered, the presence of a binary source manifests with a path
that largely differs from that expected for single-source events. Here, we
investigate the astrometric signatures of binary sources taking into account
their orbital motion and the parallax effect due to the Earth motion, which
turn out not to be negligible in most cases. We also show that considering the
above-mentioned effects is important in the analysis of astrometric data in
order to correctly estimate the lens-event parameters.


title:
Unlikely intersections in products of families of elliptic curves and
  the multiplicative group

abstract:
  Let $E_\lambda$ be the Legendre elliptic curve of equation
$Y^2=X(X-1)(X-\lambda)$. We recently proved that, given $n$ linearly
independent points $P_1(\lambda), \dots,P_n(\lambda)$ on $E_\lambda$ with
coordinates in $\bar{\mathbb{Q}(\lambda)}$, there are at most finitely many
complex numbers $\lambda_0$ such that the points $P_1(\lambda_0),
\dots,P_n(\lambda_0)$ satisfy two independent relations on $E_{\lambda_0}$. In
this article we continue our investigations on Unlikely Intersections in
families of abelian varieties and consider the case of a curve in a product of
two non-isogenous families of elliptic curves and in a family of split
semi-abelian varieties.


title:
A nonlinear structural subgrid-scale closure for compressible MHD Part
  I: derivation and energy dissipation properties

abstract:
  Compressible magnetohydrodynamic (MHD) turbulence is ubiquitous in
astrophysical phenomena ranging from the intergalactic to the stellar scales.
In studying them, numerical simulations are nearly inescapable, due to the
large degree of nonlinearity involved. However the dynamical ranges of these
phenomena are much larger than what is computationally accessible. In large
eddy simulations (LES), the resulting limited resolution effects are addressed
explicitly by introducing to the equations of motion additional terms
associated with the unresolved, subgrid-scale (SGS) dynamics. This renders the
system unclosed. We derive a set of nonlinear structural closures for the ideal
MHD LES equations with particular emphasis on the effects of compressibility.
The closures are based on a gradient expansion of the finite-resolution
operator (W.K. Yeo CUP 1993, ed. Galperin & Orszag) and require no assumptions
about the nature of the flow or magnetic field. Thus the scope of their
applicability ranges from the sub- to the hyper-sonic and -Alfvenic regimes.
The closures support spectral energy cascades both up and down-scale, as well
as direct transfer between kinetic and magnetic resolved and unresolved energy
budgets. They implicitly take into account the local geometry, and in
particular the anisotropy, of the flow. Their properties are $\textit{a
priori}$ validated in an accompanying article (Grete et al. Phys. Plasmas,
2016) against alternative closures available in the literature with respect to
a wide range of simulation data of homogeneous and isotropic turbulence.

categories: physics.flu-dyn astro-ph.GA astro-ph.SR physics.comp-ph physics.plasm-ph