title: Efficient vortex generation in sub-wavelength epsilon-near-zero slabs

abstract:
  We show that a homogeneous and isotropic slab, illuminated by a circularly
polarized beam with no topological charge, produces vortices of order two in
the opposite circularly polarized components of the reflected and transmitted
fields, as a consequence of the difference between transverse magnetic and
transverse electric dynamics. In the epsilon-near-zero regime, we find that
vortex generation is remarkably efficient in sub-wavelength thick slabs up to
the paraxial regime. This physically stems from the fact that a vacuum paraxial
field can excite a nonparaxial field inside an epsilon-near-zero slab since it
hosts slowly varying fields over physically large portion of the bulk. Our
theoretical predictions indicate that epsilon-near-zero media hold great
potential as nanophotonic elements for manipulating the angular momentum of the
radiation, since they are available without resorting to complicated micro/nano
fabrication processes and can operate even at very small (ultraviolet)
wavelengths.


title: An Existence Criterion for Low-Dimensional Materials

abstract:
  The discovery of graphene and other two-dimensional (2-D) materials has
stimulated a general interest in low-dimensional (low-D) materials. Whereas
long time ago, Peierls and Landau's theoretical work demonstrated that any one-
and two-dimensional materials could not exist in any finite temperature
environment. Then, two basic issues became a central concern for many
researchers: How can stable low-D materials exist? What kind of low-D materials
are stable? Here, we establish an energy stability criterion for low-D
materials, which seeks to provide a clear answer to these questions. For a
certain kind of element, the stability of its specific low-D structure is
determined by several derivatives of its interatomic potential. This
atomistic-based approach is then applied to study any straight/planar, low-D,
equal-bond-length elemental materials. We found that 1-D monatomic chains, 2-D
honeycomb lattices, square lattices, and triangular lattices are the only four
permissible structures, and the stability of these structures can only be
understood by assuming multi-body interatomic potentials. Using this approach,
the stable existence of graphene, silicene and germanene can be explained.


title:
Prethermalization and Persistent Order in the Absence of a Thermal Phase
  Transition

abstract:
  We numerically study the dynamics after a parameter quench in the
one-dimensional transverse-field Ising model with long-range interactions
($\propto 1/r^\alpha$ with distance $r$), for finite chains and also directly
in the thermodynamic limit. In nonequilibrium, i.e., before the system settles
into a thermal state, we find a long-lived regime that is characterized by a
prethermal value of the magnetization, which in general differs from its
thermal value. We find that the ferromagnetic phase is stabilized dynamically:
as a function of the quench parameter, the prethermal magnetization shows a
transition between a symmetry-broken and a symmetric phase, even for those
values of $\alpha$ for which no finite-temperature transition occurs in
equilibrium. The dynamical critical point is shifted with respect to the
equilibrium one, and the shift is found to depend on $\alpha$ as well as on the
quench parameters.


title: Searching for New Physics in Semi-Leptonic Baryon Decays

abstract:
  We propose two different and complementary observables for singling out
possible signals of physics beyond the standard model in the semi-leptonic
decays $\Lambda_b \to \Lambda_c \ell{\bar \nu}_{\ell}$, both with the $\tau$
lepton and with a light lepton. The two observables are the partial decay width
and a T-odd asymmetry, whose respective sensitivities to scalar and/or
pseudo-scalar coupling are calculated as functions of the parameters
characterizing new physics. Two different form factors are used. Three
particular cases are discussed and analyzed in detail.


title: Linear Combinations of Unordered Data Vectors

abstract:
  Data vectors generalise finite multisets: they are finitely supported
functions into a commutative monoid. We study the question if a given data
vector can be expressed as a finite sum of others, only assuming that 1) the
domain is countable and 2) the given set of base vectors is finite up to
permutations of the domain.
  Based on a succinct representation of the involved permutations as integer
linear constraints, we derive that positive instances can be witnessed in a
bounded subset of the domain.
  For data vectors over a group we moreover study when a data vector is
reversible, that is, if its inverse is expressible using only nonnegative
coefficients. We show that if all base vectors are reversible then the
expressibility problem reduces to checking membership in finitely generated
subgroups. Moreover, checking reversibility also reduces to such membership
tests.
  These questions naturally appear in the analysis of counter machines extended
with unordered data: namely, for data vectors over $(\mathbb{Z}^d,+)$
expressibility directly corresponds to checking state equations for Coloured
Petri nets where tokens can only be tested for equality. We derive that in this
case, expressibility is in NP, and in P for reversible instances. These upper
bounds are tight: they match the lower bounds for standard integer vectors
(over singleton domains).


title:
The Gray image of constacyclic codes over the finite chain ring
  $F_{p^m}[u]/\langle u^k\rangle$

abstract:
  Let $\mathbb{F}_{p^m}$ be a finite field of cardinality $p^m$, where $p$ is a
prime, and $k, N$ be any positive integers. We denote $R_k=F_{p^m}[u]/\langle
u^k\rangle =F_{p^m}+uF_{p^m}+\ldots+u^{k-1}F_{p^m}$ ($u^k=0$) and
$\lambda=a_0+a_1u+\ldots+a_{k-1}u^{k-1}$ where $a_0, a_1,\ldots, a_{k-1}\in
F_{p^m}$ satisfying $a_0\neq 0$ and $a_1=1$. Let $r$ be a positive integer
satisfying $p^{r-1}+1\leq k\leq p^r$. We defined a Gray map from $R_k$ to
$F_{p^m}^{p^r}$ first, then prove that the Gray image of any linear
$\lambda$-constacyclic code over $R_k$ of length $N$ is a distance invariant
linear $a_0^{p^r}$-constacyclic code over $F_{p^m}$ of length $p^rN$.
Furthermore, the generator polynomials for each linear $\lambda$-constacyclic
code over $R_k$ of length $N$ and its Gray image are given respectively.
Finally, some optimal constacyclic codes over $F_{3}$ and $F_{5}$ are
constructed.


title: Dynamical role of Polyakov loops in the QCD thermodynamics

abstract:
  Polyakov loops $L_a(T), a=3,8,...$ are shown to give the most important
nonperturbative contribution to the thermodynamic potentials. Derived from the
gluonic field correlators they enter as factors into free energy. It is shown
in the $SU(3)$ case that $L_a (T)$ define to a large extent the behavior of the
free energy and the trace anomaly $I(T)$, most sensitive to nonperturbative
effects.


title: ${\bar D}D$ meson pair production in antiproton-nucleus collisions

abstract:
  We study the $\bar D D$ (${\bar D}^0 D^0$ and $D^-D^+$) charm meson pair
production in antiproton (${\bar p}$) induced reactions on nuclei at beam
energies ranging from threshold to several GeV. Our model is based on an
effective Lagrangian approach that has only the baryon-meson degrees of freedom
and involves the physical hadron masses. The reaction proceeds via the
$t$-channel exchanges of $\Lambda_c^+$, $\Sigma_c^+$, and $\Sigma_c^{++}$
baryons in the initial collision of the antiproton with one of the protons of
the target nucleus. The medium effects on the exchanged baryons are included by
incorporating in the corresponding propagators, the effective charm baryon
masses calculated within a quark-meson coupling (QMC) model. The wave functions
of the bound proton have been determined within the QMC model as well as in a
phenomenological model where they are obtained by solving the Dirac equation
with appropriate scalar and vector potentials. The initial- and final-state
distortion effects have been approximated by using an eikonal
approximation-based procedure. Detailed numerical results are presented for
total and double differential cross sections for the ${\bar D}^0 D^0$ and
$D^-D^+$ production reactions on $^{16}$O and $^{90}$Zr targets. It is noticed
that at ${\bar p}$ beam momenta of interest to the ${\bar P}ANDA$ experiment,
medium effects lead to noticeable enhancements in the charm meson production
cross sections.


title: Left Invariant Randers Metrics of Berwald type on Tangent Lie Groups

abstract:
  Let $G$ be a Lie group equipped with a left invariant Randers metric of
Berward type $F$, with underlying left invariant Riemannian metric $g$. Suppose
that $\widetilde{F}$ and $\widetilde{g}$ are lifted Randers and Riemannian
metrics arising from $F$ and $g$ on the tangent Lie group $TG$ by vertical and
complete lifts. In this article we study the relations between the flag
curvature of the Randers manifold $(TG,\widetilde{F})$ and the sectional
curvature of the Riemannian manifold $(G,g)$ when $\widetilde{F}$ is of Berwald
type. Then we give all simply connected $3$-dimentional Lie groups such that
their tangent bundles admit Randers metrics of Berwarld type and their
geodesics vectors.


title:
Bounding the order of a graph using its diameter and metric dimension: a
  study through tree decompositions and VC dimension

abstract:
  The metric dimension of a graph is the minimum size of a set of vertices such
that each vertex is uniquely determined by the distances to the vertices of
that set. Our aim is to upper-bound the order $n$ of a graph in terms of its
diameter $d$ and metric dimension $k$. In general, the bound $n\leq d^k+k$ is
known to hold. We prove a bound of the form $n=\mathcal{O}(kd^2)$ for trees and
outerplanar graphs (for trees we determine the best possible bound and the
corresponding extremal examples). More generally, for graphs having a tree
decomposition of width $w$ and length $\ell$, we obtain a bound of the form
$n=\mathcal{O}(kd^2(2\ell+1)^{3w+1})$. This implies in particular that
$n=\mathcal{O}(kd^{\mathcal{O}(1)})$ for graphs of constant treewidth and
$n=\mathcal{O}(f(k)d^2)$ for chordal graphs, where $f$ is a doubly-exponential
function. Using the notion of distance-VC dimension (introduced in 2014 by
Bousquet and Thomass\'e) as a tool, we prove the bounds $n\leq (dk+1)^{t-1}+1$
for $K_t$-minor-free graphs, and $n\leq (dk+1)^{d(3\cdot 2^{r}+2)}+1$ for
graphs of rankwidth at most $r$.


title: $\ell_1$ Regularized Gradient Temporal-Difference Learning

abstract:
  In this paper, we study the Temporal Difference (TD) learning with linear
value function approximation. It is well known that most TD learning algorithms
are unstable with linear function approximation and off-policy learning. Recent
development of Gradient TD (GTD) algorithms has addressed this problem
successfully. However, the success of GTD algorithms requires a set of well
chosen features, which are not always available. When the number of features is
huge, the GTD algorithms might face the problem of overfitting and being
computationally expensive. To cope with this difficulty, regularization
techniques, in particular $\ell_1$ regularization, have attracted significant
attentions in developing TD learning algorithms. The present work combines the
GTD algorithms with $\ell_1$ regularization. We propose a family of $\ell_1$
regularized GTD algorithms, which employ the well known soft thresholding
operator. We investigate convergence properties of the proposed algorithms, and
depict their performance with several numerical experiments.


title: Hom-Lie-Rinehart Algebras

abstract:
  We introduce hom-Lie-Rinehart algebras as an algebraic analogue of hom-Lie
algebroids, and systematically describe a cohomology complex by considering
coefficient modules. We define the notion of extensions for hom-Lie-Rinehart
algebras. In the sequel, we deduce a characterisation of low dimensional
cohomology spaces in terms of the group of automorphisms of certain abelian
extension and the equivalence classes of those abelian extensions in the
category of hom-Lie-Rinehart algebras, respectively. We also construct a
canonical example of hom-Lie-Rinehart algebra associated to a given Poisson
algebra and an automorphism.


title:
Perspective Functions: Proximal Calculus and Applications in
  High-Dimensional Statistics

abstract:
  Perspective functions arise explicitly or implicitly in various forms in
applied mathematics and in statistical data analysis. To date, no systematic
strategy is available to solve the associated, typically nonsmooth,
optimization problems. In this paper, we fill this gap by showing that proximal
methods provide an efficient framework to model and solve problems involving
perspective functions. We study the construction of the proximity operator of a
perspective function under general assumptions and present important instances
in which the proximity operator can be computed explicitly or via
straightforward numerical operations. These results constitute central building
blocks in the design of proximal optimization algorithms. We showcase the
versatility of the framework by designing novel proximal algorithms for
state-of-the-art regression and variable selection schemes in high-dimensional
statistics.


title: The recurrence function of a random Sturmian word

abstract:
  This paper describes the probabilistic behaviour of a random Sturmian word.
It performs the probabilistic analysis of the recurrence function which can be
viewed as a waiting time to discover all the factors of length $n$ of the
Sturmian word. This parameter is central to combinatorics of words. Having
fixed a possible length $n$ for the factors, we let $\alpha$ to be drawn
uniformly from the unit interval $[0,1]$, thus defining a random Sturmian word
of slope $\alpha$. Thus the waiting time for these factors becomes a random
variable, for which we study the limit distribution and the limit density.


title:
Effective models of quantum gravity induced by Planck scale
  modifications in the covariant quantum algebra

abstract:
  In this paper we introduce a modified covariant quantum algebra based in the
so-called Quesne-Tkachuk algebra. By means of a deformation procedure we arrive
at a class of higher derivative models of gravity. The study of the particle
spectra of these models reveals an equivalence with the physical content of the
well-known renormalizable and super-renormalizable higher derivative gravities.
The particle spectrum exhibits the presence of spurious complex ghosts and, in
light of this problem, we suggest an interesting interpretation in the context
of minimal length theories. Also, a discussion regarding the non-relativistic
potential energy is proposed.


title:
Vision-based Control of a Soft Robot for Maskless Head and Neck Cancer
  Radiotherapy

abstract:
  This work presents an on-going investigation of the control of a pneumatic
soft-robot actuator addressing accurate patient positioning systems in maskless
head and neck cancer radiotherapy. We employ two RGB-D sensors in a sensor
fusion scheme to better estimate a patient's head pitch motion. A system
identification prediction error model is used to obtain a linear time invariant
state space model. We then use the model to design a linear quadratic Gaussian
feedback controller to manipulate the patient head position based on sensed
head pitch motion. Experiments demonstrate the success of our approach.


title:
DASH: A C++ PGAS Library for Distributed Data Structures and Parallel
  Algorithms

abstract:
  We present DASH, a C++ template library that offers distributed data
structures and parallel algorithms and implements a compiler-free PGAS
(partitioned global address space) approach. DASH offers many productivity and
performance features such as global-view data structures, efficient support for
the owner-computes model, flexible multidimensional data distribution schemes
and inter-operability with STL (standard template library) algorithms. DASH
also features a flexible representation of the parallel target machine and
allows the exploitation of several hierarchically organized levels of locality
through a concept of Teams. We evaluate DASH on a number of benchmark
applications and we port a scientific proxy application using the MPI two-sided
model to DASH. We find that DASH offers excellent productivity and performance
and demonstrate scalability up to 9800 cores.


title: Seismic waves in a three-dimensional block medium

abstract:
  We study numerically the propagation of seismic waves in a three-dimensional
block medium. The medium is modeled by a spatial lattice of masses connected by
elastic springs and viscous dampers. We study Lamb's problem under a surface
point vertical load. The cases of both step and pulse load are considered. The
displacements and velocities are calculated for surface masses. The influence
of the viscosity of the dampers on the attenuation of perturbations is studied.
We compare our numerical results for the block medium with known analytical
solutions for the elastic medium.


title:
Microresonator solitons for massively parallel coherent optical
  communications

abstract:
  Optical solitons are waveforms that preserve their shape while propagating,
relying on a balance of dispersion and nonlinearity. Soliton-based data
transmission schemes were investigated in the 1980s, promising to overcome the
limitations imposed by dispersion of optical fibers. These approaches, however,
were eventually abandoned in favor of wavelength-division multiplexing (WDM)
schemes that are easier to implement and offer improved scalability to higher
data rates. Here, we show that solitons may experience a comeback in optical
communications, this time not as a competitor, but as a key element of
massively parallel WDM. Instead of encoding data on the soliton itself, we
exploit continuously circulating dissipative Kerr solitons (DKS) in a
microresonator. DKS are generated in an integrated silicon nitride
microresonator by four-photon interactions mediated by Kerr nonlinearity,
leading to low-noise, spectrally smooth and broadband optical frequency combs.
In our experiments, we use two interleaved soliton Kerr combs to transmit a
data stream of more than 50Tbit/s on a total of 179 individual optical carriers
that span the entire telecommunication C and L bands. Equally important, we
demonstrate coherent detection of a WDM data stream by using a pair of
microresonator Kerr soliton combs - one as a multi-wavelength light source at
the transmitter, and another one as a corresponding local oscillator (LO) at
the receiver. This approach exploits the scalability advantages of
microresonator soliton comb sources for massively parallel optical
communications both at the transmitter and receiver side. Taken together, the
results prove the significant potential of these sources to replace arrays of
continuous-wave lasers in high-speed communications.


title:
Optimal run-and-tumble based transportation of a Janus particle with
  active steering

abstract:
  Even though making artificial micrometric swimmers has been made possible by
using various propulsion mechanisms, guiding their motion in the presence of
thermal fluctuations still remains a great challenge. Such a task is essential
in biological systems, which present a number of intriguing solutions that are
robust against noisy environmental conditions as well as variability in
individual genetic makeup. Using synthetic Janus particles driven by an
electric field, we present a feedback-based particle guiding method, quite
analogous to the "run-and-tumbling" behavior of Escherichia coli but with a
deterministic steering in the tumbling phase: the particle is set to the "run"
state when its orientation vector aligns with the target, while the transition
to the "steering" state is triggered when it exceeds a tolerance angle
{\alpha}. The active and deterministic reorientation of the particle is
achieved by a characteristic rotational motion that can be switched on and off
by modulating the AC frequency of the electric field, first reported in this
work. Relying on numerical simulations and analytical results, we show that
this feedback algorithm can be optimized by tuning the tolerance angle
{\alpha}. The optimal resetting angle depends on signal to noise ratio in the
steering state, and it is demonstrated in the experiment. Proposed method is
simple and robust for targeting, despite variability in self-propelling speeds
and angular velocities of individual particles.


title:
A tentative model for dimensionless phoneme distance from binary
  distinctive features

abstract:
  This work proposes a tentative model for the calculation of dimensionless
distances between phonemes; sounds are described with binary distinctive
features and distances show linear consistency in terms of such features. The
model can be used as a scoring function for local and global pairwise alignment
of phoneme sequences, and the distances can be used as prior probabilities for
Bayesian analyses on the phylogenetic relationship between languages,
particularly for cognate identification in cases where no empirical prior
probability is available.


title: Algebraic flows on Shimura varieties

abstract:
  In this paper we formulate some conjectures about algebraic flows on Shimura
varieties. In the first part of the paper we prove the `logarithmic
Ax-Lindemann theorem'. We then prove a result concerning the topological
closure of the images of totally geodesic subvarieties of symmetric spaces
uniformising Shimura varieties. This is a special case of our conjectures.


title: o-minimal flows on abelian varieties

abstract:
  Let $A$ be an abelian variety over ${\bf C}$ of dimension $n$ and $\pi\colon
{\bf C}^n \rightarrow A$ be the complex uniformisation. Let $X$ be an unbounded
subset of ${\bf C}^n$ definable in a suitable o-minimal structure. We give a
description of the Zariski closure of $\pi(X)$.


title:
Experimental Determination of Demand Response Control Models and Cost of
  Control for Ensembles of Window-Mount Air Conditioners

abstract:
  Control of consumer electrical devices for providing electrical grid services
is expanding in both the scope and the diversity of loads that are engaged in
control, but there are few experimentally-based models of these devices
suitable for control designs and for assessing the cost of control. A
laboratory-scale test system is developed to experimentally evaluate the use of
a simple window-mount air conditioner for electrical grid regulation services.
The experimental test bed is a single, isolated air conditioner embedded in a
test system that both emulates the thermodynamics of an air conditioned room
and also isolates the air conditioner from the real-world external
environmental and human variables that perturb the careful measurements
required to capture a model that fully characterizes both the control response
functions and the cost of control. The control response functions and cost of
control are measured using harmonic perturbation of the temperature set point
and a test protocol that further isolates the air conditioner from low
frequency environmental variability.


title: Exact Holography of the Mass-deformed M2-brane Theory

abstract:
  We test the holographic relation between the vacuum expectation values of
gauge invariant operators in ${\cal N} = 6$ ${\rm U}_k(N)\times {\rm
U}_{-k}(N)$ mass-deformed ABJM theory and the LLM geometries with
$\mathbb{Z}_k$ orbifold in 11-dimensional supergravity. To do that, we apply
the Kaluza-Klein reduction to construct a 4-dimensional gravity theory and
implement the holographic renormalization procedure. We obtain an exact
holographic relation for the vacuum expectation values of the chiral primary
operator with conformal dimension $\Delta = 1$, which is given by $\langle
{\cal O}^{(\Delta=1)}\rangle= N^{\frac32} \, f_{(\Delta=1)}$, for large $N$ and
$k=1$. Here factor $f_{(\Delta)}$ is independent of $N$. Our results involve
infinite number of exact dual relations for all possible supersymmetric Higgs
vacua and so provide a nontrivial test of gauge/gravity duality away from the
conformal fixed point. We also extend our results to the case of $k\ne 1$ for
LLM geometries represented by rectangular-shaped Young-diagrams.


title: On Volterra functions and Ramanujan integrals

abstract:
  Volterra functions were introduced at the beginning of the twentieth century
as solutions of some integral equations of convolution type with logarithmic
kernel. Since then, few authors have studied this family of functions and faced
with the problem of providing a clear understanding of their asymptotic
behaviour for small and large arguments. This paper reviews some of the most
important results on Volterra functions and in particular collects, into a
quite general framework, several results on their asymptotic expansions, these
results turn out to be useful not only for the full understanding of the
behaviour of the Volterra functions but also for their numerical computation.
The connections with integrals of Ramanujan type, which have several important
applications, are also discussed.


title:
Recovering Multiple Nonnegative Time Series From a Few Temporal
  Aggregates

abstract:
  Motivated by electricity consumption metering, we extend existing nonnegative
matrix factorization (NMF) algorithms to use linear measurements as
observations, instead of matrix entries. The objective is to estimate multiple
time series at a fine temporal scale from temporal aggregates measured on each
individual series. Furthermore, our algorithm is extended to take into account
individual autocorrelation to provide better estimation, using a recent convex
relaxation of quadratically constrained quadratic program. Extensive
experiments on synthetic and real-world electricity consumption datasets
illustrate the effectiveness of our matrix recovery algorithms.


title:
Construction of hazard maps of Hantavirus contagion using Remote
  Sensing, logistic regression and Artificial Neural Networks: case Araucan\'ia
  Region, Chile

abstract:
  In this research, methods and computational results based on statistical
analysis and mathematical modelling, data collection in situ in order to make a
hazard map of Hanta Virus infection in the region of Araucania, Chile are
presented. The development of this work involves several elements such as
Landsat satellite images, biological information regarding seropositivity of
Hanta Virus and information concerning positive cases of infection detected in
the region. All this information has been processed to find a function that
models the danger of contagion in the region, through logistic regression
analysis and Artificial Neural Networks


title: Holomorphic curves in compact Shimura varieties

abstract:
  We prove a hyperbolic analogue of the Bloch-Ochiai theorem about the Zariski
closure of holomorphic curves in abelian varieties.


title:
The Static Center of Pressure Sensitivity: a further Criterion to assess
  Contact Stability and Balancing Controllers

abstract:
  Legged locomotion has received increasing attention from the robotics
community. In this respect, contact stability plays a critical role in ensuring
that robots maintain balance, and it is a key element for balancing and walking
controllers. The Center of Pressure is a contact stability criterion that
defines a point that must be kept strictly inside the support polygon in order
to ensure postural stability. In this paper, we introduce the concept of the
sensitivity of the static center of pressure: roughly speaking, the rate of
change of the center of pressure with respect to the system equilibrium
configurations. This new concept can be used as an additional criterion to
assess the robustness of the contact stability. We show how the sensitivity of
the center of pressure can also be used as a metric to assess balancing
controllers by considering two state-of-the-art control strategies. The
analytical analysis is performed on a simplified model, and validated during
balancing tasks on the iCub humanoid robot.


title:
From Tracking to Robust Maneuver Regulation: an Easy-to-Design Approach
  for VTOL Aerial Robots

abstract:
  In this paper we present a maneuver regulation scheme for Vertical Take-Off
and Landing (VTOL) micro aerial vehicles (MAV). Differently from standard
trajectory tracking, maneuver regulation has an intrinsic robustness due to the
fact that the vehicle is not required to chase a virtual target, but just to
stay on a (properly designed) desired path with a given velocity profile. In
this paper we show how a robust maneuver regulation controller can be easily
designed by converting an existing tracking scheme. The resulting maneuvering
controller has three main appealing features, namely it: (i) inherits the
robustness properties of the tracking controller, (ii) gains the appealing
features of maneuver regulation, and (iii) does not need any additional tuning
with respect to the tracking controller. We prove the correctness of the
proposed scheme and show its effectiveness in experiments on a nano-quadrotor.
In particular, we show on a nontrivial maneuver how external disturbances
acting on the quadrotor cause instabilities in the standard tracking, while
marginally affect the maneuver regulation scheme.


title: The NUTs and Bolts of Squashed Holography

abstract:
  We evaluate the partition function of the free O(N) model on a two-parameter
family of squashed three spheres. We also find new solutions of general
relativity with negative cosmological constant and the same double squashed
boundary geometry and analyse their thermodynamic properties. Remarkably, both
systems exhibit a qualitatively similar behaviour over the entire configuration
space of boundary geometries. Recent formulations of dS/CFT enable one to
interpret the field theory partition function as a function of the two
squashing parameters as the Hartle-Hawking wave function in a minisuperspace
model of anisotropic deformations of de Sitter space. The resulting probability
distribution is normalisable and globally peaked at the round three sphere,
with a low amplitude of boundary geometries with negative scalar curvature.


title:
The Evolution of Star Formation Activity in Cluster Galaxies Over
  $0.15<z<1.5$

abstract:
  We explore 7.5 billion years of evolution in the star formation activity of
massive ($M_{\star}>10^{10.1}\,M_{\odot}$) cluster galaxies using a sample of
25 clusters over $0.15<z<1$ from the Cluster Lensing And Supernova survey with
Hubble and 11 clusters over $1<z<1.5$ from the IRAC Shallow Cluster Survey.
Galaxy morphologies are determined visually using high-resolution Hubble Space
Telescope images. Using the spectral energy distribution fitting code CIGALE,
we measure star formation rates, stellar masses, and 4000 \AA\ break strengths.
The latter are used to separate quiescent and star-forming galaxies (SFGs).
From $z\sim1.3$ to $z\sim0.2$, the specific star formation rate (sSFR) of
cluster SFGs and quiescent galaxies decreases by factors of three and four,
respectively. Over the same redshift range, the sSFR of the entire cluster
population declines by a factor of 11, from $0.48\pm0.06\;\mathrm{Gyr}^{-1}$ to
$0.043\pm0.009\;\mathrm{Gyr}^{-1}$. This strong overall sSFR evolution is
driven by the growth of the quiescent population over time; the fraction of
quiescent cluster galaxies increases from $28^{+8}_{-19}\%$ to $88^{+5}_{-4}\%$
over $z\sim1.3\rightarrow0.2$. The majority of the growth occurs at
$z\gtrsim0.9$, where the quiescent fraction increases by 0.41. While the sSFR
of the majority of star-forming cluster galaxies is at the level of the field,
a small subset of cluster SFGs have low field-relative star formation activity,
suggestive of long-timescale quenching. The large increase in the fraction of
quiescent galaxies above $z\sim0.9$, coupled with the field-level sSFRs of
cluster SFGs, suggests that higher redshift cluster galaxies are likely being
quenched quickly. Assessing those timescales will require more accurate stellar
population ages and star formation histories.


title:
Nonautonomous Riccati difference equation with real $k$-periodic ($k\geq
  1$) coefficients

abstract:
  We study the non-autonomous Riccati difference equation
\[x_{n+1}=\frac{a_nx_n+b_n}{c_nx_n+d_n}, \ n=0,1,2,\cdots\] where
$(a_n)_{n\geq0}, \ (b_n)_{n\geq0}, \ (c_n)_{n\geq0}, \ \text{and} \
(d_n)_{n\geq0}$ are $k$-periodic sequences, $k\geq 1$, with initial value $x_0
\in \mathbb{R}$. Precisely we give a detailed analysis of the forbidden set and
the character of the solutions.


title:
The sum of the interior angles in geodesic and translation triangles of
  Sl2(R) geometry

abstract:
  We study the interior angle sums of translation and geodesic triangles in the
universal cover of Sl2(R) geometry. We prove that the angle sum is larger then
pi for translation triangles and for geodesic triangles the angle sum can be
larger, equal or lessthan \pi.


title: Hawking radiation conference, book of proceedings

abstract:
  Proceedings of the 'Hawking Radiation' conference in Stockholm, Sweden 2015.
It includes a link to the video recording of the conference and all the talks,
discussions, and communications, that took place during the week of the
conference . We hope the recorded discussions will be helpful, especially to
the current and future young researchers and students.


title: Template shape estimation: correcting an asymptotic bias

abstract:
  We use tools from geometric statistics to analyze the usual estimation
procedure of a template shape. This applies to shapes from landmarks, curves,
surfaces, images etc. We demonstrate the asymptotic bias of the template shape
estimation using the stratified geometry of the shape space. We give a Taylor
expansion of the bias with respect to a parameter $\sigma$ describing the
measurement error on the data. We propose two bootstrap procedures that
quantify the bias and correct it, if needed. They are applicable for any type
of shape data. We give a rule of thumb to provide intuition on whether the bias
has to be corrected. This exhibits the parameters that control the bias'
magnitude. We illustrate our results on simulated and real shape data.


title: On the $h \to V \ell^+ \ell^-$ decays

abstract:
  A set of exclusive decays of the Higgs boson into a vector meson and a
dilepton pair ($h\to V \ell^+ \ell^-$, with $V=\Upsilon, J/\psi,\phi$, and
$\ell=\mu, \tau$) are studied in the framework of the Standard Model. We have
evaluated the decay rates, the dilepton mass spectra and the $V$ longitudinal
helicity fraction distributions. In the same framework, we considered the
exclusive modes $h\to V \nu \bar \nu$ and the implications of the CMS and ATLAS
results for the lepton flavor-changing process $h\to \tau^+ \mu^-$ on the $h\to
V \tau^+ \mu^-$ decay modes.


title: The fuzzy space construction kit

abstract:
  Fuzzy spaces like the fuzzy sphere or the fuzzy torus have received
remarkable attention, since they appeared as objects in string theory. Although
there are many higher dimensional examples, the most known and most studied
fuzzy spaces are realized as matrix algebras defined by three Hermitian
matrices, which may be seen as fuzzy membranes or fuzzy surfaces. We give a
mapping between directed graphs and matrix algebras defined by three Hermitian
matrices and show that the matrix algebras of known two-dimensional fuzzy
spaces are associated with unbranched graphs. By including branchings into the
graphs we find matrix algebras that represent fuzzy spaces associated with
surfaces having genus 2 and higher.


title:
Holographical aspects of dyonic black holes: Massive gravity
  generalization

abstract:
  The content of this paper includes studying holographical and thermodynamical
aspects of dyonic black holes in the presence of massive gravity. For the first
part of paper, thermodynamical properties of the bulk which includes black
holes are studied and the main focus is on critical behavior. It will be shown
that the existence of massive gravitons introduces remnant for temperature
after evaporation of black holes, van der Waals phase transition for
non-spherical black holes and etc. The consistency of different thermodynamical
approaches toward critical behavior of the black holes is presented and the
physical properties near the region of thermal instability are given. Next part
of the paper studies holographical aspects of the boundary theory.
Magnetization and susceptibility of the boundary are extracted and the
conditions for having diamagnetic and paramagnetic behaviors are investigated.
It will be shown that generalization to massive gravity results into the
existence of diamagnetic/paramagnetic phases in phase structure of the
hyperbolic and horizon flat of boundary conformal field theory.


title: Factorization in mixed norm Hardy and BMO spaces

abstract:
  Let $1\leq p,q < \infty$ and $1\leq r \leq \infty$. We show that the direct
sum of mixed norm Hardy spaces $\big(\sum_n H^p_n(H^q_n)\big)_r$ and the sum of
their dual spaces $\big(\sum_n H^p_n(H^q_n)^*\big)_r$ are both primary. We do
so by using Bourgain's localization method and solving the finite dimensional
factorization problem. In particular, we obtain that the spaces
$\big(\sum_{n\in \mathbb N} H_n^1(H_n^s)\big)_r$, $\big(\sum_{n\in \mathbb N}
H_n^s(H_n^1)\big)_r$, as well as $\big(\sum_{n\in \mathbb N}
BMO_n(H_n^s)\big)_r$ and $\big(\sum_{n\in \mathbb N} H^s_n(BMO_n)\big)_r$, $1 <
s < \infty$, $1\leq r \leq \infty$, are all primary.


title:
Systematic evaluation of a new combinatorial curvature for complex
  networks

abstract:
  We have recently introduced Forman's discretization of Ricci curvature to the
realm of complex networks. Forman curvature is an edge-based measure whose
mathematical definition elegantly encapsulates the weights of nodes and edges
in a complex network. In this contribution, we perform a comparative analysis
of Forman curvature with other edge-based measures such as edge betweenness,
embeddedness and dispersion in diverse model and real networks. We find that
Forman curvature in comparison to embeddedness or dispersion is a better
indicator of the importance of an edge for the large-scale connectivity of
complex networks. Based on the definition of the Forman curvature of edges,
there are two natural ways to define the Forman curvature of nodes in a
network. In this contribution, we also examine these two possible definitions
of Forman curvature of nodes in diverse model and real networks. Based on our
empirical analysis, we find that in practice the unnormalized definition of the
Forman curvature of nodes with the choice of combinatorial node weights is a
better indicator of the importance of nodes in complex networks.


title: VoxML: A Visualization Modeling Language

abstract:
  We present the specification for a modeling language, VoxML, which encodes
semantic knowledge of real-world objects represented as three-dimensional
models, and of events and attributes related to and enacted over these objects.
VoxML is intended to overcome the limitations of existing 3D visual markup
languages by allowing for the encoding of a broad range of semantic knowledge
that can be exploited by a variety of systems and platforms, leading to
multimodal simulations of real-world scenarios using conceptual objects that
represent their semantic values.


title:
Long-period oscillations of active region patterns: least-squares
  mapping on second-order curves

abstract:
  Active regions (ARs) are the main sources of variety in solar dynamic events.
Automated detection and identification tools need to be developed for solar
features for a deeper understanding of the solar cycle. Of particular interest
here are the dynamical properties of the ARs, regardless of their internal
structure and sunspot distribution. We studied the oscillatory dynamics of two
ARs: NOAA 11327 and NOAA 11726 using two different methods of pattern
recognition. We developed a novel method of automated AR border detection and
compared it to an existing method for the proof-of-concept. The first method
uses least-squares fitting on the smallest ellipse enclosing the AR, while the
second method applies regression on the convex hull.} After processing the
data, we found that the axes and the inclination angle of the ellipse and the
convex hull oscillate in time. These oscillations are interpreted as the second
harmonic of the standing long-period kink oscillations (with the node at the
apex) of the magnetic flux tube connecting the two main sunspots of the ARs. In
both ARs we have estimated the distribution of the phase speed magnitude along
the magnetic tubes (along the two main spots) by interpreting the obtained
oscillation of the inclination angle as the standing second harmonic kink mode.
After comparing the obtained results for fast and slow kink modes, we conclude
that both of these modes are good candidates to explain the observed
oscillations of the AR inclination angles, as in the high plasma $\beta$ regime
the phase speeds of these modes are comparable and on the order of the
Alfv\'{e}n speed. Based on the properties of the observed oscillations, we
detected the appropriate depth of the sunspot patterns, which coincides with
estimations made by helioseismic methods. The latter analysis can be used as a
basis for developing a magneto-seismological tool for ARs.

categories: astro-ph.SR astro-ph.EP astro-ph.IM physics.data-an physics.flu-dyn


title: A solvable counterexample to the Hambleton-Taylor-Williams Conjecture

abstract:
  I. Hambleton, L. Taylor and B. Williams conjectured a general formula in
spirit of H. Lenstra for the decomposition of $G_n(RG)$ for any finite group
$G$ and noetherian ring $R.$ The conjectured decomposition was shown to hold
for some large classes of finite groups. D. Webb and D. Yao discovered that the
conjecture failed for the symmetric group $S_5$, but remarked that it still
might be reasonable to expect the HTW-decomposition for solvable groups. In
this paper we show that the solvable group $\mathrm{SL}(2,\mathbb{F}_3)$ is
also a counterexample to the conjectured HTW-decomposition. Furthermore, we
prove that for any finite group $G$ the rank of $G_1(\mathbb{Z}G)$ does not
exceed the rank of the expression in the HTW-decomposition.


title: Modeling Data-Plane Power Consumption of Future Internet Architectures

abstract:
  With current efforts to design Future Internet Architectures (FIAs), the
evaluation and comparison of different proposals is an interesting research
challenge. Previously, metrics such as bandwidth or latency have commonly been
used to compare FIAs to IP networks. We suggest the use of power consumption as
a metric to compare FIAs. While low power consumption is an important goal in
its own right (as lower energy use translates to smaller environmental impact
as well as lower operating costs), power consumption can also serve as a proxy
for other metrics such as bandwidth and processor load.
  Lacking power consumption statistics about either commodity FIA routers or
widely deployed FIA testbeds, we propose models for power consumption of FIA
routers. Based on our models, we simulate scenarios for measuring power
consumption of content delivery in different FIAs. Specifically, we address two
questions: 1) which of the proposed FIA candidates achieves the lowest energy
footprint; and 2) which set of design choices yields a power-efficient network
architecture? Although the lack of real-world data makes numerous assumptions
necessary for our analysis, we explore the uncertainty of our calculations
through sensitivity analysis of input parameters.


title:
Can galaxy clusters, type Ia supernovae and cosmic microwave background
  rule out a class of modified gravity theories?

abstract:
  In this paper we study cosmological signatures of modified gravity theories
that can be written as a coupling between a extra scalar field and the
electromagnetic part of the usual Lagrangian for the matter fields. In these
frameworks all the electromagnetic sector of the theory is affected and
variations of fundamental constants, of the cosmic distance duality relation
and of the evolution law of the cosmic microwave background radiation (CMB) are
expected and are related each other. In order to search these variations we
perform jointly analyses with angular diameter distances of galaxy clusters,
luminosity distances of type Ia supernovae and $T_{CMB}(z)$ measurements. We
obtain tight constraints with no indication of violation of the standard
framework.


title:
Ultra-low transmission loss (7.7 dB/km at 750 nm) inhibited-coupling
  guiding hollow-core photonic crystal fibers with a single ring of tubular
  lattice cladding

abstract:
  The advent of photonic bandgap (PBG) guiding hollow- core photonic crystal
fiber (HC-PCF) sparked the hope of guiding light with attenuation below the
fundamental silica Rayleigh scattering limit (SRSL) of conventional step-index
fibers. Unfortunately, the combination of the strong core-cladding
optical-overlap, the surface roughness at the silica cladding struts and the
presence of interface-modes limited the lowest reported transmission-loss to
1.2 dB/km at 1550 nm. This hope is recently revived by the introduction of
hypocycloid core- contour (i.e. negative curvature) in inhibited-coupling (IC)
guiding HC-PCF, and the reduction of their confinement loss to a level that
makes them serious contenders for light transmission below the SRSL in UV-
VIS-NIR spectral range. Here, we report on several IC guiding HC-PCFs with a
hypocycloid core-contour and a cladding structure made of a single ring from a
tubular lattice. The fibers guide in the UV-VIS and NIR, and among which we
list one with a record transmission loss of 7.7 dB/km at ~750 nm (only a factor
~2 above the SRSL), and a second with an ultra-broad fundamental-band with loss
in the range of 10-20 dB/km spanning from 600 to 1200 nm. Both fibers present
near-single mode guidance and very low bend loss sensitivity. The results show
that the limit in the transmission is set by confinement loss for wavelengths
longer than ~1 {\mu}m and by surface- roughness for shorter wavelengths, thus
indicating that transmission loss well below the SRSL in the visible is
possible with a surface roughness reduction and would open the possibility of
the first UV low-loss light- guidance.


title: Theoretical studies of the reaction e+ e- --> K+ K- gamma

abstract:
  We present studies of the e+ e- --> K+ K- gamma reaction for the e+e-
center-of-mass energies close to the phi(1020) meson mass. Different mechanisms
leading to the final state are considered. The strong interaction amplitudes of
the K+K- pairs in the S-wave are taken into account. In addition, the photon
emission in the initial state, the final state radiation effects and all the
possible interference terms are included in the transition matrix elements. The
K+K- effective mass distributions and the angular dependence of the reaction
cross-section are calculated.


title: Soft Cone Metric Spaces and Some Fixed Point Theorems

abstract:
  This paper is an introduction to soft cone metric spaces. We define the
concept of soft cone metric via soft element, investigate soft converges in
soft cone metric spaces and prove some fixed point theorems for contractive
mappings on soft cone metric spaces.


title: Experimental Characterization of In Vivo Wireless Communication Channels

abstract:
  In vivo wireless medical devices have a critical role in healthcare
technologies due to their continuous health monitoring and noninvasive surgery
capabilities. In order to fully exploit the potential of such devices, it is
necessary to characterize the in vivo wireless communication channel which will
help to build reliable and high-performance communication systems. This paper
presents preliminary results of experimental characterization for this
fascinating communications medium on a human cadaver and compares the results
with numerical studies.


title:
A universal equation for calculating the energy gradient function in
  shear driven flows using the energy gradient theory

abstract:
  The energy gradient theory was proposed in our previous studies. The
mechanism of flow instability is very different in shear driven flows from
pressure driven flows. In present paper, the relationship for the energy
variation, work done, and energy dissipation in unit volumetric fluid of
incompressible flow is derived. A universal equation for calculating the energy
gradient function in shear driven flows is presented. With the calculation of
the energy gradient function which is a field variable and is considered as a
local Reynolds number, the stability of a basic flow can be analyzed. The
method can be applied to parallel flows, curved flows, and various complex
flows.


title: Elliptic-Curves Cryptography on High-Dimensional Surfaces

abstract:
  We discuss the use of elliptic curves in cryptography on high-dimensional
surfaces. In particular, instead of a Diffie-Hellman key exchange protocol
written in the form of a bi-dimensional row, where the elements are made up
with 256 bits, we propose a key exchange protocol given in a matrix form, with
four independent entries each of them constructed with 64 bits. Apart from the
great advantage of significantly reducing the number of used bits, this
methodology appears to be immune to attacks of the style of Western, Miller,
and Adleman, and at the same time it is also able to reach the same level of
security as the cryptographic system presently obtained by the Microsoft
Digital Rights Management. A nonlinear differential equation (NDE) admitting
the elliptic curves as a special case is also proposed. The study of the class
of solutions of this NDE is in progress.


title:
Critical behavior of non-hydrodynamic quasinormal modes in a strongly
  coupled plasma

abstract:
  We study the behavior of quasinormal modes in a top-down holographic dual
corresponding to a strongly coupled $\mathcal{N} = 4$ super Yang-Mills plasma
charged under a $U(1)$ subgroup of the global $SU(4)$ R-symmetry. In
particular, we analyze the spectra of quasinormal modes in the external scalar
and vector diffusion channels near the critical point and obtain the behavior
of the characteristic equilibration times of the plasma as the system evolves
towards the critical point of its phase diagram. Except close to the critical
point, we observe that by increasing the chemical potential one generally
increases the damping rate of the quasinormal modes, which leads to a reduction
of the characteristic equilibration times in the dual strongly coupled plasma.
However, as one approaches the critical point the typical equilibration time
(as estimated from the lowest non-hydrodynamic quasinormal mode frequency)
increases, although remaining finite, while its derivative with respect to the
chemical potential diverges with exponent -1/2. We also find a purely imaginary
non-hydrodynamical mode in the vector diffusion channel at nonzero chemical
potential which dictates the equilibration time in this channel near the
critical point.


title:
Comparative study of LSA vs Word2vec embeddings in small corpora: a case
  study in dreams database

abstract:
  Word embeddings have been extensively studied in large text datasets.
However, only a few studies analyze semantic representations of small corpora,
particularly relevant in single-person text production studies. In the present
paper, we compare Skip-gram and LSA capabilities in this scenario, and we test
both techniques to extract relevant semantic patterns in single-series dreams
reports. LSA showed better performance than Skip-gram in small size training
corpus in two semantic tests. As a study case, we show that LSA can capture
relevant words associations in dream reports series, even in cases of small
number of dreams or low-frequency words. We propose that LSA can be used to
explore words associations in dreams reports, which could bring new insight
into this classic research area of psychology


title:
Supersaturation in Posets and Applications Involving the Container
  Method

abstract:
  We consider 'supersaturation' problems in partially ordered sets (posets) of
the following form. Given a finite poset $P$ and an integer $m$ greater than
the cardinality of the largest antichain in $P$, what is the minimum number of
comparable pairs in a subset of $P$ of cardinality $m$? We provide a framework
for obtaining lower bounds on this quantity based on counting comparable pairs
relative to a random chain and apply this framework to obtain supersaturation
results for three classical posets: the boolean lattice, the collection of
subspaces of $\mathbb{F}_q^n$ ordered by set inclusion and the set of divisors
of the square of a square-free integer under the 'divides' relation. The bound
that we obtain for the boolean lattice can be viewed as an approximate version
of a known theorem of Kleitman.
  In addition, we apply our supersaturation results to obtain (a) upper bounds
on the number of antichains in these posets and (b) asymptotic bounds on the
cardinality of the largest antichain in $p$-random subsets of these posets
which hold with high probability (for $p$ in a certain range). The proofs of
these results rely on a 'container-type' lemma for posets which generalises a
result of Balogh, Mycroft and Treglown. We also state a number of open problems
regarding supersaturation in posets and counting antichains.


title: Magnetic White Dwarfs with Heavy Elements

abstract:
  Using our newly developed model atmosphere code appropriate for magnetic
white dwarfs with metal lines in the Paschen-Back regime, we study various
magnetic white dwarfs and explore the effects of various parameters such as the
field geometry and the convective efficiency


title:
How to fold a spin chain: Integrable boundaries of the Heisenberg XXX
  and Inozemtsev hyperbolic models

abstract:
  We present a general method of folding an integrable spin chain, defined on a
line, to obtain an integrable open spin chain, defined on a half-line. We
illustrate our method through two fundamental models with sl(2) Lie algebra
symmetry: the Heisenberg XXX and the Inozemtsev hyperbolic spin chains. We
obtain new long-range boundary Hamiltonians and demonstrate that they exhibit
Yangian symmetries, thus ensuring integrability of the models we obtain. The
method presented provides a "bottom-up" approach for constructing integrable
boundaries and can be applied to any spin chain model.


title: The argmin process of random walks, Brownian motion and L\'evy processes

abstract:
  In this paper we investigate the argmin process of Brownian motion $B$
defined by $\alpha_t:=\sup\left\{s \in [0,1]: B_{t+s}=\min_{u \in [0,1]}B_{t+u}
\right\}$ for $t \geq 0$. The argmin process $\alpha$ is stationary,with
invariant measure which is arcsine distributed. We prove that $(\alpha_t; t
\geq 0)$ is a Markov process with the Feller property, and provide its
transition kernel $Q_t(x,\cdot)$ for $t>0$ and $x \in [0,1]$. Similar results
for the argmin process of random walks and L\'evy processes are derived. We
also consider Brownian extrema of a given length. We prove that these extrema
form a delayed renewal process with an explicit path construction. We also give
a path decomposition for Brownian motion at these extrema


title: Lifted Message Passing for the Generalized Belief Propagation

abstract:
  We introduce the lifted Generalized Belief Propagation (GBP) message passing
algorithm, for the computation of sum-product queries in Probabilistic
Relational Models (e.g. Markov logic network). The algorithm forms a compact
region graph and establishes a modified version of message passing, which
mimics the GBP behavior in a corresponding ground model. The compact graph is
obtained by exploiting a graphical representation of clusters, which reduces
cluster symmetry detection to isomorphism tests on small local graphs. The
framework is thus capable of handling complex models, while remaining
domain-size independent.


title: Marginally Interpretable Generalized Linear Mixed Models

abstract:
  Two popular approaches for relating correlated measurements of a non-Gaussian
response variable to a set of predictors are to fit a marginal model using
generalized estimating equations and to fit a generalized linear mixed model by
introducing latent random variables. The first approach is effective for
parameter estimation, but leaves one without a formal model for the data with
which to assess quality of fit or make predictions for future observations. The
second approach overcomes the deficiencies of the first, but leads to parameter
estimates that must be interpreted conditional on the latent variables. Further
complicating matters, obtaining marginal summaries from a generalized linear
mixed model often requires evaluation of an analytically intractable integral
or use of attenuation factors that are not exact. We define a class of
marginally interpretable generalized linear mixed models that lead to parameter
estimates with a marginal interpretation while maintaining the desirable
statistical properties of a conditionally-specified model. We discuss the form
of these models under various common link functions and also address
computational issues associated with these models. For logistic mixed effects
models, we introduce an accurate and efficient method for evaluating the
logistic-normal integral.


title: Riemannian Hilbert manifolds

abstract:
  In this article we collect results obtained by the authors jointly with other
authors and we discuss old and new ideas. In particular we discuss
singularities of the exponential map, completeness and homogeneity for
Riemannian Hilbert quotient manifolds. We also extend a Theorem due to Nomizu
and Ozeki to infinite dimensional Riemannian Hilbert manifolds.


title: An efficient numerical approach for delayed logistic models

abstract:
  In the paper an efficient semi-analytical approach based on the method of
steps and differential transformation is proposed for numerical approximation
of solutions of retarded logistic models of delayed and neutral type, including
models with several constant delays. Algorithms for both commensurate and
non-commensurate delays are described, applications are shown in examples.
Validity and efficiency of the presented algorithms is compared with
variational iteration method, Adomian decomposition method and polynomial least
squares method numerically. Matlab package DDE23 is used to produce reference
numerical values.


title:
All-optical control of unipolar pulse generation in a resonant medium
  with nonlinear field coupling

abstract:
  We study optical response of a resonant medium possessing nonlinear coupling
to external field driven by a few-cycle pump pulse sequence. We demonstrate the
possibility to directly produce unipolar half-cycle pulses from the medium
possessing an arbitrary nonlinearity, by choosing the proper pulse-to-pulse
distance of the pump pulses in the sequence. We examine the various ways of the
shaping of the medium response using different geometrical configurations of
nonlinear oscillators and different wavefront shapes for the excitation pulse
sequence. Our approach defines a general framework to produce unipolar pulses
of controllable form.


title:
Thermal transport in suspended silicon membranes measured by
  laser-induced transient gratings

abstract:
  Studying thermal transport at the nanoscale poses formidable experimental
challenges due both to the physics of the measurement process and to the issues
of accuracy and reproducibility. The laser-induced transient thermal grating
(TTG) technique permits non-contact measurements on nanostructured samples
without a need for metal heaters or any other extraneous structures, offering
the advantage of inherently high absolute accuracy. We present a review of
recent studies of thermal transport in nanoscale silicon membranes using the
TTG technique. An overview of the methodology, including an analysis of
measurements errors, is followed by a discussion of new findings obtained from
measurements on both solid and nanopatterned membranes. The most important
results have been a direct observation of non-diffusive phonon-mediated
transport at room temperature and measurements of thickness-dependent thermal
conductivity of suspended membranes across a wide thickness range, showing good
agreement with first-principles-based theory assuming diffuse scattering at the
boundaries. Measurements on a membrane with a periodic pattern of nanosized
holes indicated fully diffusive transport and yielded thermal diffusivity
values in agreement with Monte Carlo simulations. Based on the results obtained
to-date, we conclude that room-temperature thermal transport in membranebased
silicon nanostructures is now reasonably well understood.


title: The Sparse T1 Theorem

abstract:
  We impose standard $ T1 $-type assumptions on a Calder\'on-Zygmund operator $
T $, and deduce that for bounded compactly supported functions $ f, g $ there
is a sparse bilinear form $ \Lambda $ so that $$ \lvert \langle T f, g
\rangle\rvert \lesssim \Lambda (f,g). $$ The proof is short and elementary. The
sparse bound quickly implies all the standard mapping properties of a
Calder\'on-Zygmund on a (weighted) $ L ^{p}$ space.


title: Cohomology of flat currents on definable pseudomanifolds

abstract:
  We show that the cohomology of flat currents on definable pseudomanifolds in
polynomially bounded o-minimal structures is isomorphic to its intersection
cohomology in the top perversity.


title: Non-supersymmetric AdS and the Swampland

abstract:
  We propose to sharpen the weak gravity conjecture by the statement that,
except for BPS states in a supersymmetric theory, the gravitational force is
strictly weaker than any electric force and provide a number of evidences for
this statement. Our conjecture implies that any non-supersymmetric anti-de
Sitter vacuum supported by fluxes must be unstable, as is the case for all
known attempts at such holographic constructions.


title: Exotic orbits due to spin-spin coupling around Kerr black holes

abstract:
  We report exotic orbital phenomena of spinning test particles orbiting around
a Kerr black hole, i.e., some orbits of spinning particles are asymmetrical
about the equatorial plane. When a nonspinning test particle orbits around a
Kerr black hole in a strong field region, due to relativistic orbital
precessions, the pattern of trajectories is symmetrical about the equatorial
plane of the Kerr black hole. However, the patterns of the spinning particles'
orbit are no longer symmetrical about the equatorial plane for some orbital
configurations and large spins. We argue that these asymmetrical patterns come
from the spin-spin interactions between spinning particles and Kerr black
holes, because the directions of spin-spin forces can be arbitrary, and
distribute asymmetrically about the equatorial plane.


title: A retract theorem for nilpotent Lie groups

abstract:
  Let $G= \exp(\g)$ be a connected, simply connected nilpotent Lie group. We
show that for every $G$-invariant smooth sub-manifold $M$ of $g^*$, there
exists an open relatively compact subset $\mathcal{M}$ of $M$ such that for any
smooth adapted field of operators $(F(l))_{l\in M}$ supported in $G\cdot
\mathcal{M}$ there exists a Schwartz function $f$ on $G$ such that $\pi_l(f)=
\op_{F(l)}$ for all $l\in M$. This retract theorem can then be used to show
that for every Lie group $\G$ of automorphisms of $G$ containing the inner
automorphisms of $G$ with locally closed $\G$-orbits in $\g^*$, the proper
$\G$-prime two-sided closed ideals of $L^1(G)$ are the kernels of $\G$-orbits
in $\hat{G}$.


title: TARGET: A Digitizing And Trigger ASIC For The Cherenkov Telescope Array

abstract:
  The future ground-based gamma-ray observatory Cherenkov Telescope Array (CTA)
will feature multiple types of imaging atmospheric Cherenkov telescopes, each
with thousands of pixels. To be affordable, camera concepts for these
telescopes have to feature low cost per channel and at the same time meet the
requirements for CTA in order to achieve the desired scientific goals. We
present the concept of the TeV Array Readout Electronics with GSa/s sampling
and Event Trigger (TARGET) Application Specific Circuit (ASIC), envisaged to be
used in the cameras of various CTA telescopes, e.g. the Gamma-ray Cherenkov
Telescope (GCT), a proposed 2-Mirror Small-Sized Telescope, and the
Schwarzschild-Couder Telescope (SCT), a proposed Medium-Sized Telescope. In the
latest version of this readout concept the sampling and trigger parts are split
into dedicated ASICs, TARGET C and T5TEA, both providing 16 parallel input
channels. TARGET C features a tunable sampling rate (usually 1 GSa/s), a 16k
sample deep buffer for each channel and on-demand digitization and transmission
of waveforms with typical spans of ~100 ns. The trigger ASIC, T5TEA, provides 4
low voltage differential signal (LVDS) trigger outputs and can generate a
pedestal voltage independently for each channel. Trigger signals are generated
by T5TEA based on the analog sum of the input in four independent groups of
four adjacent channels and compared to a threshold set by the user. Thus, T5TEA
generates four LVDS trigger outputs, as well as 16 pedestal voltages fed to
TARGET C independently for each channel. We show preliminary results of the
characterization and testing of TARGET C and T5TEA.


title: Scale and curvature effects in principal geodesic analysis

abstract:
  There is growing interest in using the close connection between differential
geometry and statistics to model smooth manifold-valued data. In particular,
much work has been done recently to generalize principal component analysis
(PCA), the method of dimension reduction in linear spaces, to Riemannian
manifolds. One such generalization is known as principal geodesic analysis
(PGA). This paper, in a novel fashion, obtains Taylor expansions in scaling
parameters introduced in the domain of objective functions in PGA. It is shown
this technique not only leads to better closed-form approximations of PGA but
also reveals the effects that scale, curvature and the distribution of data
have on solutions to PGA and on their differences to first-order tangent space
approximations. This approach should be able to be applied not only to PGA but
also to other generalizations of PCA and more generally to other intrinsic
statistics on Riemannian manifolds.


title:
A Theoretical Model for Understanding the Dynamics of Online Social
  Networks Decay

abstract:
  Online social networks represent a main source of communication and
information exchange in today's life. They facilitate exquisitely news sharing,
knowledge elicitation, and forming groups of same interests. Researchers in the
last two decades studied the growth dynamics of the online social networks
extensively questing a clear understanding of the behavior of humans in online
social networks that helps in many directions, like engineering better
recommendation systems and attracting new members. However, not all of social
networks achieved the desired growth, for example, online social networks like
MySpace, Orkut, and Friendster are out of service today. In this work, we
present a probabilistic theoretical model that captures the dynamics of the
social decay due to the inactivity of the members of a social network. The
model is proved to have some interesting mathematical properties, namely
\textit{submodularity}, which imply achieving the model optimization in a
reasonable performance. That means the maximization problem can be approximated
within a factor of $(1-1/e)$ and the minimization problem can be achieved in
polynomial time.


title: On the causality aspects of the dynamical Chern-Simons modified gravity

abstract:
  We discuss the G\"{o}del-type solutions within the dynamical Chern-Simons
modified gravity in four dimensions. Within our study, we show that in the
vacuum case the causal solutions are possible which cannot take place within
the non-dynamical framework. Another our result consists in the possibility for
completely causal solutions for all types of matters we study in the paper,
that is, relativistic fluid, cosmological constant, scalar and electromagnetic
fields.


title:
Universal front propagation in the quantum Ising chain with domain-wall
  initial states

abstract:
  We study the melting of domain walls in the ferromagnetic phase of the
transverse Ising chain, created by flipping the order-parameter spins along
one-half of the chain. If the initial state is excited by a local operator in
terms of Jordan-Wigner fermions, the resulting longitudinal magnetization
profiles have a universal character. Namely, after proper rescalings, the
profiles in the noncritical Ising chain become identical to those obtained for
a critical free-fermion chain starting from a step-like initial state. The
relation holds exactly in the entire ferromagnetic phase of the Ising chain and
can even be extended to the zero-field XY model by a duality argument. In
contrast, for domain-wall excitations that are highly non-local in the
fermionic variables, the universality of the magnetization profiles is lost.
Nevertheless, for both cases we observe that the entanglement entropy
asymptotically saturates at the ground-state value, suggesting a simple form of
the steady state.


title:
Stable determination of an inclusion in an inhomogeneous elastic body by
  boundary measurements

abstract:
  In this paper we consider the stability issue for the inverse problem of
determining an unknown inclusion contained in an elastic body by all the pairs
of measurements of displacement and traction taken at the boundary of the body.
Both the body and the inclusion are made by inhomogeneous linearly elastic
isotropic material. Under mild a priori assumptions about the smoothness of the
inclusion and the regularity of the coefficients, we show that the logarithmic
stability estimate proved in \cite{ADiCMR14} in the case of piecewise constant
coefficients continues to hold in the inhomogeneous case. We introduce new
arguments which allow to simplify some technical aspects of the proof given in
\cite{ADiCMR14}.


title: Holographic Complexity for Time-Dependent Backgrounds

abstract:
  In this paper, we will analyse the holographic complexity for time-dependent
asymptotically $AdS$ geometries. We will first use a covariant zero mean
curvature slicing of the time-dependent bulk geometries, and then use this
co-dimension one spacelike slice of the bulk spacetime to define a co-dimension
two minimal surface. The time-dependent holographic complexity will be defined
using the volume enclosed by this minimal surface. This time-dependent
holographic complexity will reduce to the usual holographic complexity for
static geometries. We will analyse the time-dependence as a perturbation of the
asymptotically $AdS$ geometries. Thus, we will obtain time-dependent
asymptotically $AdS$ geometries, and we will calculate the holographic
complexity for such a time-dependent geometries.


title:
How Zwicky already ruled out modified gravity theories without dark
  matter

abstract:
  Various theories, such as MOND, MOG, Emergent Gravity and $f(R)$ theories
avoid dark matter by assuming a change in General Relativity and/or in Newton's
law. Galactic rotation curves are typically described well. Here the
application to galaxy clusters is considered, focussed on the good lensing and
X-ray data for A1689. As a start, the no-dark-matter case is confirmed to work
badly: the need for dark matter starts near the cluster centre, where Newton's
law is still supposed to be valid. This leads to the conundrum discovered by
Zwicky, which is likely only solvable in his way, namely by assuming additional
(dark) matter. Neutrinos with eV masses serve well without altering the
successes in (dwarf) galaxies.


title:
A note on a generalization of eigenvector centrality for bipartite
  graphs and applications

abstract:
  Eigenvector centrality is a linear algebra based graph invariant used in
various rating systems such as webpage ratings for search engines. A
generalization of the eigenvector centrality invariant is defined which is
motivated by the need to design rating systems for bipartite graph models of
time-sensitive and other processes. The linear algebra connection and some
applications are described.


title: Antigravity: Spin-gravity coupling in action

abstract:
  The typical motions of a spinning test particle in Schwarzschild's background
which show the strong repulsive action of the highly relativistic spin-gravity
coupling are considered using the exact Mathisson-Papapetrou equations. An
approximated approach to choice solutions of these equations which describe
motions of the particle's proper center of mass is developed.


title: Conversational Recommendation System with Unsupervised Learning

abstract:
  We will demonstrate a conversational products recommendation agent. This
system shows how we combine research in personalized recommendation systems
with research in dialogue systems to build a virtual sales agent. Based on new
deep learning technologies we developed, the virtual agent is capable of
learning how to interact with users, how to answer user questions, what is the
next question to ask, and what to recommend when chatting with a human user.
  Normally a descent conversational agent for a particular domain requires tens
of thousands of hand labeled conversational data or hand written rules. This is
a major barrier when launching a conversation agent for a new domain. We will
explore and demonstrate the effectiveness of the learning solution even when
there is no hand written rules or hand labeled training data.


title: Symplectic quotients and representability: the circle action case

abstract:
  Let $S^1$ act on a symplectic manifold in a Hamiltonian fashion with momentum
map $\Psi$. Fix a value $a$ of $\Psi$. There is a question of whether the
symplectic quotient at $a$ is diffeomorphic to the orbit space of some proper
Lie group action. We prove under mild assumptions that this only occurs if the
symplectic quotient is diffeomorphic to an effective orbifold. This, in turn,
only occurs if $a$ is a regular value, or there is at most one positive weight
or at most one negative weight.


title:
The arrow of time in open quantum systems and dynamical breaking of the
  resonance-antiresonance symmetry

abstract:
  Open quantum systems are often represented by non-Hermitian effective
Hamiltonians that have complex eigenvalues associated with resonances. In
previous work we showed that the evolution of tight-binding open systems can be
represented by an explicitly time-reversal symmetric expansion involving all
the discrete eigenstates of the effective Hamiltonian. These eigenstates
include complex-conjugate pairs of resonant and anti-resonant states. An
initially time-reversal-symmetric state contains equal contributions from the
resonant and anti-resonant states. Here we show that as the state evolves in
time, the symmetry between the resonant and anti-resonant states is
automatically broken, with resonant states becoming dominant for $t>0$ and
anti-resonant states becoming dominant for $t<0$. Further, we show that there
is a time-scale for this symmetry-breaking, which we associate with the "Zeno
time." We also compare the time-reversal symmetric expansion with an asymmetric
expansion used previously by several researchers. We show how the present
time-reversal symmetric expansion bypasses the non-Hilbert nature of the
resonant and anti-resonant states, which previously introduced exponential
divergences into the asymmetric expansion.


title: A Novel Representation of Neural Networks

abstract:
  Deep Neural Networks (DNNs) have become very popular for prediction in many
areas. Their strength is in representation with a high number of parameters
that are commonly learned via gradient descent or similar optimization methods.
However, the representation is non-standardized, and the gradient calculation
methods are often performed using component-based approaches that break
parameters down into scalar units, instead of considering the parameters as
whole entities. In this work, these problems are addressed. Standard notation
is used to represent DNNs in a compact framework. Gradients of DNN loss
functions are calculated directly over the inner product space on which the
parameters are defined. This framework is general and is applied to two common
network types: the Multilayer Perceptron and the Deep Autoencoder.


title:
Applicability of scaling behavior and power laws in the analysis of the
  magnetocaloric effect in second-order phase transition materials

abstract:
  In recent years, universal scaling has gained renewed attention in the study
of magnetocaloric materials. It has been applied to a wide variety of pure
elements and compounds, ranging from rare earth-based materials to transition
metal alloys, from bulk crystalline samples to nanoparticles. It is therefore
necessary to quantify the limits within which the scaling laws would remain
applicable for magnetocaloric research. For this purpose, a threefold approach
has been followed: a) the magnetocaloric responses of a set of materials with
Curie temperatures ranging from 46 to 336 K have been modeled with a mean-field
Brillouin model, b) experimental data for Gd has been analyzed, and c) a
3D-Ising model ---which is beyond the mean-field approximation--- has been
studied. In this way we can demonstrate that the conclusions extracted in this
work are model-independent. It is found that universal scaling remains
applicable up to applied fields which provide a magnetic energy to the system
up to 8\% of the thermal energy at the Curie temperature. In this range, the
predicted deviations from scaling laws remain below the experimental error
margin of carefully performed experiments. Therefore, for materials whose Curie
temperature is close to room temperature, scaling laws at the Curie temperature
would be applicable for the magnetic field range available at conventional
magnetism laboratories ($\sim 10$ T), well above the fields which are usually
available for magnetocaloric devices.


title: Plasmonic nanoprobes for stimulated emission depletion microscopy

abstract:
  Plasmonic nanoparticles influence the absorption and emission processes of
nearby emitters due to local enhancements of the illuminating radiation and the
photonic density of states. Here, we use the plasmon resonance of metal
nanoparticles in order to enhance the stimulated depletion of excited molecules
for super-resolved microscopy. We demonstrate stimulated emission depletion
(STED) microscopy with gold nanorods with a long axis of only 26 nm and a width
of 8 nm that provide an enhancement of the resolution compared to
fluorescent-only probes without plasmonic components irradiated with the same
depletion power. These novel nanoparticle-assisted STED probes represent a
~2x10^3 reduction in probe volume compared to previously used nanoparticles and
we demonstrate their application to the first plasmon-assisted STED cellular
imaging. We also discuss their current limitations.


title: Perspective Functions: Properties, Constructions, and Examples

abstract:
  Many functions encountered in applied mathematics and in statistical data
analysis can be expressed in terms of perspective functions. One of the
earliest examples is the Fisher information, which appeared in statistics in
the 1920s. We analyze various algebraic and convex-analytical properties of
perspective functions and provide general schemes to construct lower
semicontinuous convex functions from them. Several new examples are presented
and existing instances are featured as special cases.


title:
Coordination of Heterogeneous Nonlinear Multi-Agent Systems with
  Prescribed Behaviors

abstract:
  In this paper, we consider a coordination problem for a class of
heterogeneous nonlinear multi-agent systems with a prescribed input-output
behavior which was represented by another input-driven system. In contrast to
most existing multi-agent coordination results with an autonomous (virtual)
leader, this formulation takes possible control inputs of the leader into
consideration. First, the coordination was achieved by utilizing a group of
distributed observers based on conventional assumptions of model matching
problem. Then, a fully distributed adaptive extension was proposed without
using the input of this input-output behavior. An example was given to verify
their effectiveness.


title:
Determining the shape of a human vocal tract from pressure measurements
  at the lips

abstract:
  The inverse problem of determining the cross-sectional area of a human vocal
tract during the utterance of a vowel is considered in terms of the data
consisting of the absolute value of sound pressure at the lips. If the upper
lip is curved downward during the utterance, it is shown that there may be up
to an $M$-fold nonuniqueness in the determination, where $M$ is the maximal
number of eligible resonances associated with a related Schr\"odinger operator.
Each of the $M$ such distinct candidates for the vocal-tract area corresponding
to the same absolute pressure is uniquely determined. The mathematical theory
is presented for the recovery of each candidate for the vocal-tract area, and
the admissibility criterion for each of the $M$ candidates to be a vocal-tract
radius is specified. On the other hand, if the upper lip is horizontal or
curved upward during the utterance, then the inverse problem has a unique
solution. The theory developed is illustrated with some examples.


title: On characterization of poised nodes for a space of bivariate functions

abstract:
  There are several examples of spaces of univariate functions for which we
have a characterization of all sets of knots which are poised for the
interpolation problem. For the standard spaces of univariate polynomials, or
spline functions the mentioned results are well-known. In contrast with this
there are no such results in the bivariate case. As an exception one may
consider only the Pascal classic theorem, in the interpolation theory
interpretation. In this paper we consider a space of bivariate piecewise linear
functions, for which we can readily find out whether the given node set is
poised or not. The main tool we use for this purpose is the reduction by a
basic subproblem, introduced in this paper.


title:
Quantum Vacuum Fluctuations in Presence of Dissipative Bodies: Dynamical
  Approach for Non-Equilibrium and Squeezed States

abstract:
  This work contributes to the study of non-equilibrium aspects of the Casimir
forces with the introduction of squeezed states in the calculations. Throughout
this article two main results can be found, being both strongly correlated.
Primarily, the more formal result involves the development of a
first-principles canonical quantization formalism to study the vacuum in
presence different dissipative bodies in completely general scenarios. We
considered a one-dimensional quantum scalar field interacting with the volume
elements' degrees of freedom of the material bodies, which are modeled as
composite systems consisting in a harmonic oscillators interacting with an
environment. Solving the full dynamics of the composite system through its
Heisenberg equations, we studied each contribution to the field operator by
employing general properties of the Green function. We deduced the long-time
limit of the field operator. In agreement with previous works, we showed that
the expectation values of the components of the energy-momentum tensor present
two contributions, one associated to the thermal baths and the other one
associated to the field's initial conditions. This allows us to the direct
study of steady situations involving different initial states for the field and
arbitrary thermal states for the baths. This leads to the other main result,
consisting in computing the Casimir force when the field is initially in
thermal or continuum-single-mode squeezed states (characterized by a given
bandwidth and frequency). Time-averaging is required for the squeezed case,
showing both results in a unified way. For the thermal state, all the
well-known equilibrium results can be successfully reproduced. Finally, we
compared the initial conditions' contribution and the total force for each
case, showing that the latter can be tuned in a wide range of values through
varying the size of the bandwidth.


title: Elliptic hypergeometric functions

abstract:
  This is author's Habilitation Thesis (Dr. Sci. dissertation) submitted at the
beginning of September 2004. It is written in Russian and is posted due to the
continuing requests for the manuscript.
  The content: 1. Introduction, 2. Nonlinear chains with the discrete time and
their self-similar solutions, 3. General theory of theta hypergeometric series,
4. Theta hypergeometric integrals, 5. Biorthogonal functions, 6. Elliptic
hypergeometric functions with |q|=1, 7. Conclusion, 8. References.
  It contains an outline of a general heuristic scheme for building univariate
special functions through self-similar reductions of spectral transformation
chains, which allowed construction of the differential-difference q-Painleve
equations, as well as of the most general known set of elliptic biorthogonal
functions comprising all classical orthogonal polynomials and biorthogonal
rational functions. One of the key results of the thesis consists in the
discovery of genuinely transcendental elliptic hypergeometric functions
determined by the elliptic hypergeometric integrals. The whole theory of such
integrals can be built from the univariate elliptic beta integral -- the most
complicated known definite integral with exact evaluation, which generalizes
the ordinary binomial theorem and its q-extension, Euler's beta integral, the
measure for Askey-Wilson polynomials, and many other previously established
results on ordinary and q-hypergeometric functions.


title:
On the construction of the correlation numbers in Minimal Liouville
  Gravity

abstract:
  The computation of the correlation numbers in Minimal Liouville Gravity
involves an integration over moduli spaces of complex curves. There are two
independent approaches to the calculation: the direct one, based on the CFT
methods and Liouville higher equations of motion, and the alternative one,
motivated by discrete description of 2D gravity and based on the Douglas string
equation. However these two approaches give rise to the results that are not
always consistent among themselves. In this paper we explore this problem. We
show that in order to reconcile two methods the so-called discrete terms in the
operator product expansion in the underlying Liouville theory must be properly
taken into account. In this way we propose modified version of the expression
for four-point correlation number and find full agreement between direct and
alternative approaches. Our result allows to consider correlators without any
restrictions on the number of conformal blocks contributing to the matter
sector correlation function.


title:
Diffusion Quantum Monte Carlo Study of Martensitic Phase Transition: The
  Case of Phosphorene

abstract:
  Recent technical advances in dealing with finite-size errors make quantum
Monte Carlo methods quite appealing for treating extended systems in electronic
structure calculations, especially when commonly-used density functional theory
(DFT) methods might not be satisfactory. We present a theoretical study of
martensitic phase transition of a two-dimensional phosphorene by employing
diffusion Monte Carlo (DMC) approach to investigate the energetics of this
phase transition. The DMC calculation supports DFT prediction of having a
rather diffusive barrier that is characterized by having two transition states,
in addition to confirming that the so-called black and blue phases of
phosphorene are essentially degenerate. At the same time, the calculation shows
the importance of treating correlation energy accurately for describing the
energy changes in the martensitic phase transition, as is already widely
appreciated for chemical bond formation/dissociation. Building on the atomistic
characterization of the phase transition process, we also discuss how
mechanical strain influences the stabilities of the two phases of phosphorene.


title:
Incidences with curves and surfaces in three dimensions, with
  applications to distinct and repeated distances

abstract:
  We study a wide spectrum of incidence problems involving points and curves or
points and surfaces in $\mathbb R^3$. The current (and in fact the only viable)
approach to such problems, pioneered by Guth and Katz [2010,2015], requires a
variety of tools from algebraic geometry, most notably (i) the polynomial
partitioning technique, and (ii) the study of algebraic surfaces that are ruled
by lines or, in more recent studies [Guth-Zahl 2016], by algebraic curves of
some constant degree. By exploiting and refining these tools, we obtain new and
improved bounds for numerous incidence problems in $\mathbb R^3$. In broad
terms, we consider two kinds of problems, those involving points and
constant-degree algebraic \emph{curves}, and those involving points and
constant-degree algebraic \emph{surfaces}. In some variants we assume that the
points lie on some fixed constant-degree algebraic variety, and in others we
consider arbitrary sets of points in 3-space. our results provide a "grand
generalization" of most of the previous studies of (special instances of)
previous works for both curves and surfaces.
  As an application of our point-curve incidence bound, we consider the problem
of bounding the number of similar triangles spanned by a set of $n$ points in
$\mathbb R^3$, and obtain the bound $O(n^{15/7}),$ thus improving the bound of
Agarwal et al [2007].
  As applications of our point-surface incidence bounds, we consider the
problems of distinct and repeated distances determined by a set of $n$ points
in $\mathbb R^3$, two of the most celebrated open problems in combinatorial
geometry. We obtain new and improved bounds for two special cases, one in which
the points lie on some algebraic variety of constant degree, and one involving
incidences between pairs in $P_1\times P_2$, where $P_1$ is contained in a
variety and $P_2$ is arbitrary.


title: Summarizing Situational and Topical Information During Crises

abstract:
  The use of microblogging platforms such as Twitter during crises has become
widespread. More importantly, information disseminated by affected people
contains useful information like reports of missing and found people, requests
for urgent needs etc. For rapid crisis response, humanitarian organizations
look for situational awareness information to understand and assess the
severity of the crisis. In this paper, we present a novel framework (i) to
generate abstractive summaries useful for situational awareness, and (ii) to
capture sub-topics and present a short informative summary for each of these
topics. A summary is generated using a two stage framework that first extracts
a set of important tweets from the whole set of information through an
Integer-linear programming (ILP) based optimization technique and then follows
a word graph and concept event based abstractive summarization technique to
produce the final summary. High accuracies obtained for all the tasks show the
effectiveness of the proposed framework.


title: Structure of continuous-time ARMA process driven by semi-Levy measure

abstract:
  A class of continuous-time autoregressive moving average (CARMA) process
driven by simple semi-Levy measure is defined and its properties are studied.
We discuss some new insights on the structure of the semi-Levy measure which is
described as periodically divisible measure. This consideration enable us to
provide statistical property of the introduced process. We show that this
process is well defined without having to assume further conditions on the
measure. We find a kernel representation of the process and present the
properties of first and second moments of it. Finally we show the efficiency of
our model by implying simulated data.


title:
DeepGaze II: Reading fixations from deep features trained on object
  recognition

abstract:
  Here we present DeepGaze II, a model that predicts where people look in
images. The model uses the features from the VGG-19 deep neural network trained
to identify objects in images. Contrary to other saliency models that use deep
features, here we use the VGG features for saliency prediction with no
additional fine-tuning (rather, a few readout layers are trained on top of the
VGG features to predict saliency). The model is therefore a strong test of
transfer learning. After conservative cross-validation, DeepGaze II explains
about 87% of the explainable information gain in the patterns of fixations and
achieves top performance in area under the curve metrics on the MIT300 hold-out
benchmark. These results corroborate the finding from DeepGaze I (which
explained 56% of the explainable information gain), that deep features trained
on object recognition provide a versatile feature space for performing related
visual tasks. We explore the factors that contribute to this success and
present several informative image examples. A web service is available to
compute model predictions at http://deepgaze.bethgelab.org.


title: Electronics lab instructors' approaches to troubleshooting instruction

abstract:
  In this exploratory qualitative study, we describe instructors' self-reported
practices for teaching and assessing students' ability to troubleshoot in
electronics lab courses. We collected audio data from interviews with 20
electronics instructors from 18 institutions that varied by size, selectivity,
and other factors. In addition to describing participants' instructional
practices, we characterize their perceptions about the role of troubleshooting
in electronics, the importance of the ability to troubleshoot more generally,
and what it means for students to be competent troubleshooters. One major
finding of this work is that, while almost all instructors in our study said
that troubleshooting is an important learning outcome for students in
electronics lab courses, only half of instructors said they directly assessed
students' ability to troubleshoot. Based on our findings, we argue that there
is a need for research-based instructional materials that attend to both
cognitive and non-cognitive aspects of troubleshooting proficiency. We also
identify several areas for future investigation related to troubleshooting
instruction in electronics lab courses.


title: Non-dominated Solution of Fuzzy Maximum-Return Problem

abstract:
  In this paper, we find a non-dominated solution of a fuzzy maximum-return
problem ( unconstrained single-variable fuzzy optimization problem ) . We
establish Newton method to find the solution of the unconstrained
single-variable fuzzy optimization problem using the differentiability of
$\alpha$-level functions of a fuzzy-valued function and partial order relation
on a set of fuzzy numbers.


title: Super-de Sitter and alternative super-Poincar\'e symmetries

abstract:
  It is well-known that de Sitter Lie algebra $\mathfrak{o}(1,4)$ contrary to
anti-de Sitter one $\mathfrak{o}(2,3)$ does not have a standard
$\mathbb{Z}_2$-graded superextension. We show here that the Lie algebra
$\mathfrak{o}(1,4)$ has a superextension based on the
$\mathbb{Z}_2\times\mathbb{Z}_2$-grading. Using the standard contraction
procedure for this superextension we obtain an {\it alternative}
super-Poincar\'e algebra with the $\mathbb{Z}_2\times\mathbb{Z}_2$-grading.


title:
Improved Jensen-type inequalities via linear interpolation and
  applications

abstract:
  In this paper we develop a general method for improving Jensen-type
inequalities for convex and, even more generally, for piecewise convex
functions. Our main result relies on the linear interpolation of a convex
function. As a consequence, we obtain improvements of some recently established
Young-type inequalities. Finally, our method is also applied to matrix case. In
such a way we obtain improvements of some important matrix inequalities known
from the literature.


title: The ratio of domination and independent domination numbers on trees

abstract:
  Let $\gamma(G)$ and $i(G)$ be the domination number and the independent
domination number of $G$, respectively. In 1977, Hedetniemi and Mitchell began
with the comparison of of $i(G)$ and $\gamma(G)$ and recently Rad and Volkmann
posted a conjecture that $i(G)/ \gamma(G) \leq \Delta(G)/2$, where $\Delta(G)$
is the maximum degree of $G$. In this work, we prove the conjecture for trees
and provide the graph achieved the sharp bound.


title: A Generalization of Sachdev-Ye-Kitaev

abstract:
  The SYK model: fermions with a $q$-body, Gaussian-random, all-to-all
interaction, is the first of a fascinating new class of solvable large $N$
models. We generalize SYK to include $f$ flavors of fermions, each occupying
$N_a$ sites and appearing with a $q_a$ order in the interaction. Like SYK, this
entire class of models generically has an infrared fixed point. We compute the
infrared dimensions of the fermions, and the spectrum of singlet bilinear
operators. We show that there is always a dimension-two operator in the
spectrum, which implies that, like in SYK, there is breaking of conformal
invariance and maximal chaos in the infrared four-point function of the
generalized model. After a disorder average, the generalized model has a global
$O(N_1) \times O(N_2) \times \ldots\times O(N_f)$ symmetry: a subgroup of the
$O(N)$ symmetry of SYK; thereby giving a richer spectrum. We also elucidate
aspects of the large $q$ limit and the OPE, and solve $q=2$ SYK at finite $N$.


title:
Current noise enhancement: channel mixing and possible nonequilibrium
  phonon backaction in atomic-scale Au junctions

abstract:
  We report measurements of the bias dependence of the Fano factor in ensembles
of atomic-scale Au junctions at 77 K. Previous measurements of shot noise at
room temperature and low biases have found good agreement of the Fano factor
with the expectations of the Landauer- B\"uttiker formalism, while enhanced
Fano factors have been observed at biases of hundreds of mV [R. Chen et al.,
Sci. Rep. 4, 4221 (2014)]. We find even stronger enhancement of shot noise at
77 K with an "excess" Fano factor up to ten times the low bias value. We
discuss the observed ensemble Fano factor bias dependence in terms of candidate
models. The results are most consistent with either a bias-dependent channel
mixing picture or a model incorporating noise enhancement due to
current-driven, nonequilibrium phonon populations, though a complete
theoretical treatment of the latter in the ensemble average limit is needed.