title:
Stable dipole solitons and soliton complexes in the nonlinear
  Schrodinger equation with periodically modulated nonlinearity

abstract:
  We develop a general classification of the infinite number of families of
solitons and soliton complexes in the one-dimensional
Gross-Pitaevskii/nonlinear Schrodinger equation with a nonlinear lattice
pseudopotential, i.e., periodically modulated coefficient in front of the cubic
term, which takes both positive and negative local values. This model finds
direct implementations in atomic Bose-Einstein condensates and nonlinear
optics. The most essential finding is the existence of two branches of dipole
solitons (DSs), which feature an antisymmetric shape, essentially squeezed into
a single cell of the nonlinear lattice. This soliton species was not previously
considered in nonlinear lattices. We demonstrate that one branch of the DS
family (namely, the one which obeys the Vakhitov-Kolokolov criterion) is
stable, while unstable DSs spontaneously transform into stable fundamental
solitons (FSs). The results are obtained in numerical and approximate
analytical forms, the latter based on the variational approximation. Some
stable bound states of FSs are found too.

categories: nlin.PS cond-mat.quant-gas math-ph math.MP


title:
AC bias characterization of low noise bolometers for SAFARI using an
  Open-Loop Frequency Domain SQUID-based multiplexer operating between 1 and 5
  MHz

abstract:
  SRON is developing the Frequency Domain Multiplexing (FDM) readout and the
ultra low NEP TES bolometers array for the infrared spectrometer SAFARI on
board of the Japanese space mission SPICA. The FDM prototype of the instrument
requires critical and complex optimizations. For single pixel characterization
under AC bias we are developing a simple FDM system working in the frequency
range from 1 to 5 MHz, based on the open loop read-out of a linearized
two-stage SQUID amplifier and high Q lithographic LC resonators. We describe
the details of the experimental set-up required to achieve low power loading (<
1 fW) and low noise (NEP $\sim 10^{-19} W/Hz^{1/2}$) in the TES bolometers. We
conclude the paper by comparing the performance of a $4 \cdot 10^{-19}
W/Hz^{1/2}$ TES bolometer measured under DC and AC bias.


title: Learning Compact Recurrent Neural Networks

abstract:
  Recurrent neural networks (RNNs), including long short-term memory (LSTM)
RNNs, have produced state-of-the-art results on a variety of speech recognition
tasks. However, these models are often too large in size for deployment on
mobile devices with memory and latency constraints. In this work, we study
mechanisms for learning compact RNNs and LSTMs via low-rank factorizations and
parameter sharing schemes. Our goal is to investigate redundancies in recurrent
architectures where compression can be admitted without losing performance. A
hybrid strategy of using structured matrices in the bottom layers and shared
low-rank factors on the top layers is found to be particularly effective,
reducing the parameters of a standard LSTM by 75%, at a small cost of 0.3%
increase in WER, on a 2,000-hr English Voice Search task.


title:
Study of the dependency on magnetic field and bias voltage of an
  AC-biased TES microcalorimeter

abstract:
  At SRON we are studying the performance of a Goddard Space Flight Center
single pixel TES microcalorimeter operated in an AC bias configuration. For
x-ray photons at 6 keV the pixel shows an x-ray energy resolution $dE_{FWHM} =
3.7\mathrm{eV}$, which is about a factor 2 worse than the energy resolution
observed in an identical DC-biased pixel. In order to better understand the
reasons for this discrepancy we characterised the detector as a function of
temperature, bias working point and applied perpendicular magnetic field. A
strong periodic dependency of the detector noise on the TES AC bias voltage is
measured. We discuss the results in the framework of the recently observed
weak-link behaviour of a TES microcalorimeter


title:
$W$-entropy formulas and Langevin deformation of flows on Wasserstein
  space over Riemannian manifolds

abstract:
  We introduce Perelman's $W$-entropy and prove the $W$-entropy formula along
the geodesic flow on the $L^2$-Wasserstein space over compact Riemannian
manifolds equipped with Otto's Riemannian metric, which allows us to recapture
a previous result due to Lott and Villani on the displacement convexity of
$s{\rm Ent}+ns\log s$ on $P^\infty_2(M)$ over Riemannian manifolds with
non-negative Ricci curvature. To better understand the similarity between the
$W$-entropy formula for the geodesic flow on the Wasserstein space and the
$W$-entropy formula for the heat equation of the Witten Laplacian on the
underlying manifolds, we introduce the Langevin deformation of flows on the
Wasserstein space over Riemannian manifold, which interpolates the gradient
flow and the geodesic flow on the Wasserstein space over Riemannian manifolds,
and can be regarded as the potential flow of the compressible Euler equation
with damping on manifolds. We prove the existence, uniqueness and regularity of
the Langevin deformation on the Wasserstein space over the Euclidean space and
compact Riemannian manifolds, and prove the convergence of the Langevin
deformation for $c\rightarrow 0$ and $c\rightarrow \infty$ respectively. We
prove an analogue of the Perelman type $W$-entropy formula along the Langevin
deformation on the Wasserstein space on Riemannian manifolds. A rigidity
theorem is proved for the $W$-entropy for the geodesic flow, and a rigidity
model is also provided for the Langevin deformation on the Wasserstein space
over complete Riemannian manifolds with the $CD(0, m)$-condition.


title: A Family of Totally Rank One Two-sided Shift Maps

abstract:
  'Generalized del Junco-Rudolph's map', a sub-family of generalized Chacon's
map (\cite{FER1}), is introduced. A skew product related to the structure of
the Generalized del Junco-Rudolph's map is introduced. A Relative Prime
Relation, $h_{k+1}\equiv 1 \mod q$ is verified, based on the proposition of
iterations of this skew product. We say a measure-preserving transformation $T$
is totally rank one if $T^{q}$ is rank one for every $q\in \mathbb{N}$. In this
paper, we show that of every Generalized del Junco-Rudolph's map is totally
rank one.


title: Species richness estimation with high diversity but spurious singletons

abstract:
  The presence of uncommon taxa in high-throughput sequenced ecological samples
pose challenges to the microbial ecologist, bioinformatician and statistician.
It is rarely certain whether these taxa are truly present in the sample or the
result of sequencing errors. Unfortunately, alpha-diversity quantification
relies on accurate frequency counts, which can rarely be guaranteed. We present
a species richness estimation tool which predicts both the number of unobserved
taxa and the number of true singletons based on the non-singleton frequency
counts. This method can be treated as either inferential (for formally
estimating richness) or exploratory (for assessing robustness of the richness
estimate to the singleton count). If the estimate, called breakaway_nof1, is
comparable to other richness estimators, this provides evidence that the
richness estimate is robust to the level of quality control (eg.
chimera-checking) employed in pre-processing. The function breakaway_nof1 is
freely available from CRAN via the R package breakaway.


title:
The existence of a global fundamental solution for homogeneous
  H\"ormander operators via a global lifting method

abstract:
  We prove the existence of a global fundamental solution $\Gamma(x;y)$ (with
pole $x$) for any H\"ormander operator $\mathcal{L}=\sum_{i=1}^m X_i^2$ on
$\mathbb{R}^n$ which is $\delta$-homogeneous of degree $2$. By means of a
global Lifting method for homogeneous operators proved by Folland in [On the
Rothschild-Stein lifting theorem, Comm. PDEs, 1977], there exists a Carnot
group $\mathbb{G}$ and a polynomial surjective map $\pi:\mathbb{G}\to
\mathbb{R}^n$ such that $\mathcal{L}$ is $\pi$-related to a sub-Laplacian
$\mathcal{L}_{\mathbb{G}}$ on $\mathbb{G}$. We show that it is always possible
to perform a (global) change of variable on $\mathbb{G}$ such that the lifting
map $\pi$ becomes the projection of $\mathbb{G}\equiv
\mathbb{R}^n\times\mathbb{R}^p$ onto $\mathbb{R}^n$. If
$\Gamma_{\mathbb{G}}(x,{x}';y,{y}')$ ($x,{x}'\in\mathbb{R}^n$;
$y,{y}'\in\mathbb{R}^p$) is the fundamental solution of
$\mathcal{L}_{\mathbb{G}}$, we show that $\Gamma_{\mathbb{G}}(x,0;y,{y}')$ is
always integrable w.r.t. ${y}'\in \mathbb{R}^p$, and its integral is a
fundamental solution for $\mathcal{L}$.


title:
A multiplexer for the ac/dc characterization of TES based bolometers and
  microcalorimeters

abstract:
  At SRON we are developing the Frequency Domain Multiplexing (FDM) for the
read-out of the TES-based detector array for the future infrared and X-ray
space mission. We describe the performances of a multiplexer designed to
increase the experimental throughput in the characterisation of ultra-low noise
equivalent power (NEP) TES bolometers and high energy resolving power X-ray
microcalorimeters arrays under ac and dc bias. We discuss the results obtained
using the TiAu TES bolometers array fabricated at SRON with measured dark NEP
below $5\cdot 10^{-19}W/Hz^{1/2}$ and saturation power of several fW


title:
Algebraic non-hyperbolicity of hyperkahler manifolds with Picard rank
  greater than one

abstract:
  A projective manifold is algebraically hyperbolic if the degree of any curve
is bounded from above by its genus times a constant, which is independent from
the curve. This is a property which follows from Kobayashi hyperbolicity. We
prove that hyperkahler manifolds are non algebraically hyperbolic when the
Picard rank is at least 3, or if the Picard rank is 2 and the SYZ conjecture on
existence of Lagrangian fibrations is true. We also prove that if the
automorphism group of a hyperkahler manifold is infinite then it is
algebraically non-hyperbolic.


title: Can Uplink Transmissions Survive in Full-duplex Cellular Environments?

abstract:
  In-band full-duplex (FD) communication is considered a potential candidate to
be adopted by the fifth generation (5G) cellular networks. FD communication
renders the entire spectrum simultaneously accessible by uplink and downlink,
and hence, is optimistically promoted to double the transmission rate. While
this is true for a single communication link, cross-mode interference (i.e.,
interference between uplink and downlink) may diminish the full-duplexing gain.
This paper studies FD operation in large-scale cellular networks with real base
stations (BSs) locations and 3GPP propagation environment. The results show
that the uplink is the bottleneck for FD operation due to the overwhelming
cross-mode interference from BSs. Operating uplink and downlink on a common set
of channels in an FD fashion improves the downlink rate but significantly
degrades (over 1000-fold) the uplink rate. Therefore, we propose the
$\alpha$-duplex scheme to balance the tradeoff between the uplink and downlink
rates via adjustable partial overlap between uplink and downlink channels. The
$\alpha$-duplex scheme can provide a simultaneous $30\%$ improvement in each of
the uplink and downlink rates. To this end, we discuss the backward
compatibility of the $\alpha$-duplex scheme with half-duplex user-terminals.
Finally, we point out future research directions for FD enabled cellular
networks.


title: Information, Processes and Games

abstract:
  We survey the prospects for an Information Dynamics which can serve as the
basis for a fundamental theory of information, incorporating qualitative and
structural as well as quantitative aspects. We motivate our discussion with
some basic conceptual puzzles: how can information increase in computation, and
what is it that we are actually computing in general? Then we survey a number
of the theories which have been developed within Computer Science, as partial
exemplifications of the kind of fundamental theory which we seek: including
Domain Theory, Dynamic Logic, and Process Algebra. We look at recent work
showing new ways of combining quantitative and qualitative theories of
information, as embodied respectively by Domain Theory and Shannon Information
Theory. Then we look at Game Semantics and Geometry of Interaction, as examples
of dynamic models of logic and computation in which information flow and
interaction are made central and explicit. We conclude by looking briefly at
some key issues for future progress.


title: A classification theorem for normal extensions

abstract:
  For a particular class of Galois structures, we prove that the normal
extensions are precisely those extensions that are "locally" split epic and
trivial, and we use this to prove a "Galois theorem" for normal extensions.
Furthermore, we interpret the normalisation functor as a Kan extension of the
trivialisation functor.


title:
Multi-State Perfect Phylogeny Mixture Deconvolution and Applications to
  Cancer Sequencing

abstract:
  The reconstruction of phylogenetic trees from mixed populations has become
important in the study of cancer evolution, as sequencing is often performed on
bulk tumor tissue containing mixed populations of cells. Recent work has shown
how to reconstruct a perfect phylogeny tree from samples that contain mixtures
of two-state characters, where each character/locus is either mutated or not.
However, most cancers contain more complex mutations, such as copy-number
aberrations, that exhibit more than two states. We formulate the Multi-State
Perfect Phylogeny Mixture Deconvolution Problem of reconstructing a multi-state
perfect phylogeny tree given mixtures of the leaves of the tree. We
characterize the solutions of this problem as a restricted class of spanning
trees in a graph constructed from the input data, and prove that the problem is
NP-complete. We derive an algorithm to enumerate such trees in the important
special case of cladisitic characters, where the ordering of the states of each
character is given. We apply our algorithm to simulated data and to two cancer
datasets. On simulated data, we find that for a small number of samples, the
Multi-State Perfect Phylogeny Mixture Deconvolution Problem often has many
solutions, but that this ambiguity declines quickly as the number of samples
increases. On real data, we recover copy-neutral loss of heterozygosity,
single-copy amplification and single-copy deletion events, as well as their
interactions with single-nucleotide variants.


title: A General Retraining Framework for Scalable Adversarial Classification

abstract:
  Traditional classification algorithms assume that training and test data come
from similar distributions. This assumption is violated in adversarial
settings, where malicious actors modify instances to evade detection. A number
of custom methods have been developed for both adversarial evasion attacks and
robust learning. We propose the first systematic and general-purpose retraining
framework which can: a) boost robustness of an \emph{arbitrary} learning
algorithm, in the face of b) a broader class of adversarial models than any
prior methods. We show that, under natural conditions, the retraining framework
minimizes an upper bound on optimal adversarial risk, and show how to extend
this result to account for approximations of evasion attacks. Extensive
experimental evaluation demonstrates that our retraining methods are nearly
indistinguishable from state-of-the-art algorithms for optimizing adversarial
risk, but are more general and far more scalable. The experiments also confirm
that without retraining, our adversarial framework dramatically reduces the
effectiveness of learning. In contrast, retraining significantly boosts
robustness to evasion attacks without significantly compromising overall
accuracy.


title: G\"odel's Notre Dame Course

abstract:
  This is a companion to a paper by the authors entitled "G\"odel's natural
deduction", which presented and made comments about the natural deduction
system in G\"odel's unpublished notes for the elementary logic course he gave
at the University of Notre Dame in 1939. In that earlier paper, which was
itself a companion to a paper that examined the links between some
philosophical views ascribed to G\"odel and general proof theory, one can find
a brief summary of G\"odel's notes for the Notre Dame course. In order to put
the earlier paper in proper perspective, a more complete summary of these
interesting notes, with comments concerning them, is given here.


title: A Case for Data Commons: Towards Data Science as a Service

abstract:
  As the amount of scientific data continues to grow at ever faster rates, the
research community is increasingly in need of flexible computational
infrastructure that can support the entirety of the data science lifecycle,
including long-term data storage, data exploration and discovery services, and
compute capabilities to support data analysis and re-analysis, as new data are
added and as scientific pipelines are refined. We describe our experience
developing data commons-- interoperable infrastructure that co-locates data,
storage, and compute with common analysis tools--and present several cases
studies. Across these case studies, several common requirements emerge,
including the need for persistent digital identifier and metadata services,
APIs, data portability, pay for compute capabilities, and data peering
agreements between data commons. Though many challenges, including
sustainability and developing appropriate standards remain, interoperable data
commons bring us one step closer to effective Data Science as Service for the
scientific research community.


title:
Entanglement negativity in a two dimensional harmonic lattice: Area law
  and corner contributions

abstract:
  We study the logarithmic negativity and the moments of the partial transpose
in the ground state of a two dimensional massless harmonic square lattice with
nearest neighbour interactions for various configurations of adjacent domains.
At leading order for large domains, the logarithmic negativity and the
logarithm of the ratio between the generic moment of the partial transpose and
the moment of the reduced density matrix at the same order satisfy an area law
in terms of the length of the curve shared by the adjacent regions. We give
numerical evidences that the coefficient of the area law term in these
quantities is related to the coefficient of the area law term in the R\'enyi
entropies. Whenever the curve shared by the adjacent domains contains vertices,
a subleading logarithmic term occurs in these quantities and the numerical
values of the corner function for some pairs of angles are obtained. In the
special case of vertices corresponding to explementary angles, we provide
numerical evidence that the corner function of the logarithmic negativity is
given by the corner function of the R\'enyi entropy of order 1/2.


title: Network Topology Identification from Spectral Templates

abstract:
  Network topology inference is a cornerstone problem in statistical analyses
of complex systems. In this context, the fresh look advocated here permeates
benefits from convex optimization and graph signal processing, to identify the
so-termed graph shift operator (encoding the network topology) given only the
eigenvectors of the shift. These spectral templates can be obtained, for
example, from principal component analysis of a set of graph signals defined on
the particular network. The novel idea is to find a graph shift that while
being consistent with the provided spectral information, it endows the network
structure with certain desired properties such as sparsity. The focus is on
developing efficient recovery algorithms along with identifiability conditions
for two particular shifts, the adjacency matrix and the normalized graph
Laplacian. Application domains include network topology identification from
steady-state signals generated by a diffusion process, and design of a graph
filter that facilitates the distributed implementation of a prescribed linear
network operator. Numerical tests showcase the effectiveness of the proposed
algorithms in recovering synthetic and structural brain networks.


title:
Modeling the near-wake of a vertical-axis cross-flow turbine with 2-D
  and 3-D RANS

abstract:
  The near-wake of a vertical-axis cross-flow turbine (CFT) was modeled
numerically via blade-resolved $k$-$\omega$ SST and Spalart-Allmaras RANS
models in two and three dimensions. Results for each case are compared with
experimental measurements of the turbine shaft power, overall drag, mean
velocity, turbulence kinetic energy, and momentum transport terms in the
near-wake at one diameter downstream. It was shown that 2-D simulations
overpredict turbine loading and do not resolve mean vertical momentum
transport, which plays an important role in the near-wake's momentum balance.
The 3-D simulations fared better at predicting performance, with the
Spalart-Allmaras model predictions being closest to the experiments. The SST
model more accurately predicted the turbulence kinetic energy while the
Spalart-Allmaras model more closely matched the momentum transport terms in the
near-wake. These results show the potential of blade-resolved RANS as a design
tool and a way to "extrapolate" experimental flow field measurements.


title:
Fusing Audio, Textual and Visual Features for Sentiment Analysis of News
  Videos

abstract:
  This paper presents a novel approach to perform sentiment analysis of news
videos, based on the fusion of audio, textual and visual clues extracted from
their contents. The proposed approach aims at contributing to the
semiodiscoursive study regarding the construction of the ethos (identity) of
this media universe, which has become a central part of the modern-day lives of
millions of people. To achieve this goal, we apply state-of-the-art
computational methods for (1) automatic emotion recognition from facial
expressions, (2) extraction of modulations in the participants' speeches and
(3) sentiment analysis from the closed caption associated to the videos of
interest. More specifically, we compute features, such as, visual intensities
of recognized emotions, field sizes of participants, voicing probability, sound
loudness, speech fundamental frequencies and the sentiment scores (polarities)
from text sentences in the closed caption. Experimental results with a dataset
containing 520 annotated news videos from three Brazilian and one American
popular TV newscasts show that our approach achieves an accuracy of up to 84%
in the sentiments (tension levels) classification task, thus demonstrating its
high potential to be used by media analysts in several applications,
especially, in the journalistic domain.


title:
Reduced radiative conductivity of high and low spin FeO6 octahedra in
  the Earth's lower mantle

abstract:
  The ability of Earths mantle to conduct heat by radiation is determined by
optical properties of mantle phases. Optical properties of mantle minerals at
high pressure are accessible through diamond anvil cell experiments, but
because of the extensive thermal radiation at T above 1000 K such studies are
limited to lower temperatures. Particularly uncertain is the
temperature-dependence of optical properties of lower mantle minerals across
the spin transition as the spin state itself is a strong function of
temperature. Here we use laser-heated DACs combined with a pulsed bright
supercontinuum laser probe and a synchronized time-gated detector to examine
optical properties of high and low spin ferrous iron at 45-73 GPa and to 1600 K
in FeO6, one of the most abundant building blocks in the mantle. Siderite
(FeCO3) is used as a model for FeO6-octahedra as it contains no ferric iron and
exhibits a sharp optically apparent spin transition at 44 GPa, simplifying data
interpretation. We find that the optical absorbance of low spin FeO6 is
substantially increased at 1000-1200 K due to the partially lifted Laporte
selection rule. The temperature-induced low to high spin transition, however,
results in a dramatic drop in absorbance of the FeO6-unit. The absorption edge
(Fe-O charge transfer) red-shifts (~ 1 cm-1/K) with increasing temperature and
at T above 1600 K becomes the dominant absorption mechanism in the visible
range, suppressing radiative conductivity. This implies that the radiative
conductivity of analogous FeO6-bearing minerals such as ferropericlase, the
second most abundant mineral in the Earths lower mantle, is substantially
reduced approaching the core-mantle boundary conditions. Finally, our results
emphasize that optical properties of mantle minerals probed at room temperature
are insufficient to model radiative thermal conductivity of planetary
interiors.


title:
On the performance of exponential integrators for problems in
  magnetohydrodynamics

abstract:
  Exponential integrators have been introduced as an efficient alternative to
explicit and implicit methods for integrating large stiff systems of
differential equations. Over the past decades these methods have been studied
theoretically and their performance was evaluated using a range of test
problems. While the results of these investigations showed that exponential
integrators can provide significant computational savings, the research on
validating this hypothesis for large scale systems and understanding what
classes of problems can particularly benefit from the use of the new techniques
is in its initial stages. Resistive magnetohydrodynamic (MHD) modeling is
widely used in studying large scale behavior of laboratory and astrophysical
plasmas. In many problems numerical solution of MHD equations is a challenging
task due to the temporal stiffness of this system in the parameter regimes of
interest. In this paper we evaluate the performance of exponential integrators
on large MHD problems and compare them to a state-of-the-art implicit time
integrator. Both the variable and constant time step exponential methods of
EpiRK-type are used to simulate magnetic reconnection and the Kelvin--Helmholtz
instability in plasma. Performance of these methods, which are part of the EPIC
software package, is compared to the variable time step variable order BDF
scheme included in the CVODE (part of SUNDIALS) library. We study performance
of the methods on parallel architectures and with respect to magnitudes of
important parameters such as Reynolds, Lundquist, and Prandtl numbers. We find
that the exponential integrators provide superior or equal performance in most
circumstances and conclude that further development of exponential methods for
MHD problems is warranted and can lead to significant computational advantages
for large scale stiff systems of differential equations such as MHD.


title: Multi-parameter Quantum Metrology

abstract:
  The simultaneous quantum estimation of multiple parameters can provide a
better precision than estimating them individually. This is an effect that is
impossible classically. We review the rich background of multi-parameter
quantum metrology, some of the main results in the field and its recent
advances. We close by highlighting future challenges and open questions.


title: Structure preserving numerical methods for the Vlasov equation

abstract:
  To preserve a number of physically relevant invariants is a major concern
when considering long time integration of the Vlasov equation. In the present
work we consider the semi-Lagrangian discontinuous Galerkin method for the
Vlasov-Poisson system. We discuss the performance of this method and compare it
to cubic spline interpolation, where appropriate. In addition, numerical
simulations for the two-stream instability are shown.


title: Explicit computations for some Markov modulated counting processes

abstract:
  In this paper we present elementary computations for some Markov modulated
counting processes, also called counting processes with regime switching.
Regime switching has become an increasingly popular concept in many branches of
science. In finance, for instance, one could identify the background process
with the `state of the economy', to which asset prices react, or as an
identification of the varying default rate of an obligor. The key feature of
the counting processes in this paper is that their intensity processes are
functions of a finite state Markov chain. This kind of processes can be used to
model default events of some companies.
  Many quantities of interest in this paper, like conditional characteristic
functions, can all be derived from conditional probabilities, which can, in
principle, be analytically computed. We will also study limit results for
models with rapid switching, which occur when inflating the intensity matrix of
the Markov chain by a factor tending to infinity. The paper is largely
expository in nature, with a didactic flavor.


title: Chordal networks of polynomial ideals

abstract:
  We introduce a novel representation of structured polynomial ideals, which we
refer to as chordal networks. The sparsity structure of a polynomial system is
often described by a graph that captures the interactions among the variables.
Chordal networks provide a computationally convenient decomposition into
simpler (triangular) polynomial sets, while preserving the underlying graphical
structure. We show that many interesting families of polynomial ideals admit
compact chordal network representations (of size linear in the number of
variables), even though the number of components is exponentially large.
Chordal networks can be computed for arbitrary polynomial systems using a
refinement of the chordal elimination algorithm from [Cifuentes-Parrilo-2016].
Furthermore, they can be effectively used to obtain several properties of the
variety, such as its dimension, cardinality, and equidimensional components, as
well as an efficient probabilistic test for radical ideal membership. We apply
our methods to examples from algebraic statistics and vector addition systems;
for these instances, algorithms based on chordal networks outperform existing
techniques by orders of magnitude.


title:
TextProposals: a Text-specific Selective Search Algorithm for Word
  Spotting in the Wild

abstract:
  Motivated by the success of powerful while expensive techniques to recognize
words in a holistic way, object proposals techniques emerge as an alternative
to the traditional text detectors. In this paper we introduce a novel object
proposals method that is specifically designed for text. We rely on a
similarity based region grouping algorithm that generates a hierarchy of word
hypotheses. Over the nodes of this hierarchy it is possible to apply a holistic
word recognition method in an efficient way.
  Our experiments demonstrate that the presented method is superior in its
ability of producing good quality word proposals when compared with
class-independent algorithms. We show impressive recall rates with a few
thousand proposals in different standard benchmarks, including focused or
incidental text datasets, and multi-language scenarios. Moreover, the
combination of our object proposals with existing whole-word recognizers shows
competitive performance in end-to-end word spotting, and, in some benchmarks,
outperforms previously published results. Concretely, in the challenging
ICDAR2015 Incidental Text dataset, we overcome in more than 10 percent f-score
the best-performing method in the last ICDAR Robust Reading Competition. Source
code of the complete end-to-end system is available at
https://github.com/lluisgomez/TextProposals


title:
Surveying Turkish high school and university student attitudes and
  approaches to physics problem solving

abstract:
  Student attitudes and approaches to problem solving can impact how well they
learn physics. Prior research in the US using a validated Attitude and
Approaches to Problem Solving (AAPS) survey suggests that there are major
differences between students in introductory physics and astronomy courses and
physics experts in terms of their attitudes and approaches to physics problem
solving. Here we discuss the validation, administration and analysis of data
for the Turkish version of the AAPS survey for high school and university
students in Turkey. After the validation and administration of the Turkish
version of the survey, the analysis of the data was conducted by grouping the
data by grade level, school type, and gender. While there are no statistically
significant differences between the averages of various groups on the survey,
overall, the university students in Turkey were more expert-like than
vocational high school students. On an item by item basis, there are
statistically differences between the averages of the groups on many items. For
example, on average, the university students demonstrated less expert-like
attitudes about the role of equations and formulas in problem solving, in
solving difficult problems, and in knowing when the solution is not correct,
whereas they displayed more expert-like attitudes and approaches on items
related to meta-cognition in physics problem solving. A principal component
analysis on the data yields item clusters into which the student responses on
various survey items can be grouped. A comparison of the responses of the
Turkish and American university students enrolled in algebra-based introductory
physics courses shows that on more than half of the items, the responses of
these two groups were statistically significantly different with the US
students on average responding to the items in more expert-like manner.


title: Applicability of dynamic facilitation theory to binary hard disk systems

abstract:
  We investigate numerically the applicability of dynamic facilitation (DF)
theory for glass-forming binary hard disk systems where supercompression is
controlled by pressure. By using novel efficient algorithms for hard disks, we
are able to generate equilibrium supercompressed states in an additive
non-equimolar binary mixture, where micro-crystallization and size segregation
do not emerge at high average packing fractions. Above an onset pressure where
collective heterogeneous relaxation sets in, we find that relaxation times are
well described by a "parabolic law" with pressure. We identify excitations, or
soft-spots, that give rise to structural relaxation, and find that they are
spatially localized, their average concentration decays exponentially with
pressure, and their associated energy scale is logarithmic in the excitation
size. These observations are consistent with the predictions of DF generalized
to systems controlled by pressure rather than temperature.


title: Variations on a Lemma of Nicolas and Serre

abstract:
  The "Nicolas-Serre code", $(a,b) \leftrightarrow t^{n}$, is a bijection
between $N\times N$ and those $t^{n}$, $n$ odd, in $Z/2[t]$. Suppose $A_{n}$,
$n$ odd, in $Z/2[t]$ are defined by: $A_{1}= A_{5}= 0$, $A_{3}= t$, $A_{7}=
t^{5}$, and $A_{n+8}= t^{8} A_{n} + t^{2} A_{n+2}$. A lemma, Proposition 4.3 of
[6], used to study the Hecke algebra attached to the space of mod $2$ level $1$
modular forms, gives information about the codes $(a,b)$ attached to the
monomials appearing in $A_{n}$. The unpublished highly technical proof has been
simplified by Gerbelli-Gauthier.
  Our Theorem 3.7 generalizes Proposition 4.3. The proof, in sections 1-3, is a
further simplification of Gerbelli-Gauthier's argument. We build up to the
theorem with variants involving the same recurrence, but having different sorts
of initial conditions.
  Section 4 treats the recurrence $A_{n+16}= t^{16} A_{n} + t^{4} A_{n+4} +
t^{2} A_{n+2}$. Theorem 4.1, the analog to Theorem 3.7 for this recurrence, is
used in [2] and [3] to analyze level 3 Hecke algebras.
  Finally we introduce a variant code, $(a,b) \leftrightarrow w^{n}$ which is a
bijection between $N\times N$ and those $w^{n}$, $n \equiv 1,3,7,9 \bmod{20}$,
in $Z/2[w]$. We then study the recurrence $A_{n+80}= w^{80} A_{n}+ w^{20}
A_{n+20}$, $n \equiv 1,3,7,9 \bmod{20}$, with appropriate initial conditions.
Lemma 5.5, derived from the results of sections 1-3, is the precise analog of
Proposition 4.3 for this code, this recurrence, and these initial conditions.
It is used in [4] and [5] to analyze level 5 Hecke algebras.


title:
Decomposing the parameter space of biological networks via a numerical
  discriminant approach

abstract:
  Many systems in biology, physics and engineering can be described by systems
of ordinary differential equation containing many parameters. When studying the
dynamic behavior of these large, nonlinear systems, it is useful to identify
and characterize the steady-state solutions as the model parameters vary, a
technically challenging problem in a high-dimensional parameter landscape.
Rather than simply determining the number and stability of steady-states at
distinct points in parameter space, we decompose the parameter space into
finitely many regions, the steady-state solutions being consistent within each
distinct region. From a computational algebraic viewpoint, the boundary of
these regions is contained in the discriminant locus. We develop global and
local numerical algorithms for constructing the discriminant locus and
classifying the parameter landscape. We showcase our numerical approaches by
applying them to molecular and cell-network models.


title: Plasmonic interaction between nanospheres

abstract:
  When metallic (or plasmonic) nanospheres are nearly touching, strong
concentration of light can occur in the narrow gap regions. This phenomenon has
a potential application in nanophotonics, biosensing and spectroscopy. The
understanding of the strong interaction between the plasmonic spheres turns out
to be quite challenging. Indeed, an extremely high computational cost is
required to compute the electromagnetic field. Also, the classical method of
image charges, which is effective for dielectric spheres system, is not valid
for plasmonic spheres because of their negative permittivities. Here we develop
new analytical and numerical methods for the plasmonic spheres system by
clarifying the connection between transformation optics and the method of image
charges. We derive fully analytic solutions valid for two plasmonic spheres. We
then develop a hybrid numerical scheme for computing the field distribution
produced by an arbitrary number of spheres. Our method is highly efficient and
accurate even in the nearly touching case and is valid for plasmonic spheres.


title: Optimal curvature estimates for homogeneous Ricci flows

abstract:
  We prove uniform curvature estimates for homogeneous Ricci flows: For a
solution defined on $[0,t]$ the norm of the curvature tensor at time $t$ is
bounded by the maximum of $C(n)/t$ and $C(n) ( scal(g(t)) - scal(g(0)) )$. This
is used to show that solutions with finite extinction time are Type I, immortal
solutions are Type III and ancient solutions are Type I, where all the
constants involved depend only on the dimension $n$. A further consequence is
that a non-collapsed homogeneous ancient solution on a compact homogeneous
space emerges from a unique Einstein metric on the same space.
  The above curvature estimates are proved using a gap theorem for
Ricci-flatness on homogeneous spaces. The proof of this gap theorem is by
contradiction and uses a local $W^{2,p}$ convergence result, which holds
without symmetry assumptions.


title:
Interfacial Dzyaloshinskii-Moriya interaction in Pt/CoFeB films: effect
  of the heavy-metal thickness

abstract:
  We report the observation of a Pt layer thickness dependence on the induced
interfacial Dzyaloshinskii-Moriya interaction in ultra-thin
Pt($d_{\text{Pt}}$)/CoFeB films. Taking advantage of the large spin-orbit
coupling of the heavy metal, the interfacial Dzyaloshinskii-Moriya interaction
is quantified by Brillouin light scattering measurements of the frequency
non-reciprocity of spin-waves in the ferromagnet. The magnitude of the induced
Dzyaloshinskii-Moriya coupling is found to saturate to a value $0.45$
mJ$/$m${}^2$ for Pt thicknesses larger than $\sim 2$ nm. The experimental
results are explained by analytical calculations based on the 3-site indirect
exchange mechanism that predicts a Dzyaloshinskii-Moriya interaction at the
interface between a ferromagnetic thin layer and a heavy metal. Our findings
open up a way to control and optimize chiral effects in ferromagnetic thin
films through the thickness of the heavy metal layer.


title: The Riemann constant for a non-symmetric Weierstrass semigroup

abstract:
  The zero divisor of the theta function of a compact Riemann surface $X$ of
genus $g$ is the canonical theta divisor of Pic${}^{(g-1)}$ up to translation
by the Riemann constant $\Delta$ for a base point $P$ of $X$. The complement of
the Weierstrass gaps at the base point $P$ given as a numerical semigroup plays
an important role, which is called the Weierstrass semigroup. It is classically
known that the Riemann constant $\Delta$ is a half period
$\frac{1}{2}\Gamma_\tau$ for the Jacobi variety
$\mathcal{J}(X)=\mathbb{C}^g/\Gamma_\tau$ of $X$ if and only if the Weierstrass
semigroup at $P$ is symmetric. In this article, we analyze the non-symmetric
case. Using a semi-canonical divisor $D_0$, we show a relation between the
Riemann constant $\Delta$ and a half period $\frac{1}{2}\Gamma_\tau$ of the
non-symmetric case. We also identify the semi-canonical divisor $D_0$ for
trigonal curves, and remark on an algebraic expression for the Jacobi inversion
problem using the relation


title:
On the second boundary value problem for a class of fully nonlinear
  flows I

abstract:
  In this paper, a class of fully nonlinear flows with nonlinear Neumann type
boundary condition is considered. This problem was solved partly by the first
author under the assumption that the flow is the parabolic type special
Lagrangian equation in $\mathbb{R}^{2n}$.
  We show that the convexity is preserved for solutions of the fully nonlinear
parabolic equations and prove the long time existence and convergence of the
flow. In particular, we can prescribe the second boundary value problems for a
family of special Lagrangian graphs in Euclidean and pseudo-Euclidean space.


title: K-theory, local cohomology and tangent spaces to Hilbert schemes

abstract:
  By using K-theory, we construct a map from the tangent space to the Hilbert
scheme at a point Y to the local cohomology group. And we use this map to
answer affirmatively(after slight modification) a question by Mark Green and
Phillip Griffiths in [8] on constructing a map from the tangent space to the
Hilbert scheme to the tangent space to the cycle group.


title:
Network Inoculation: Heteroclinics and phase transitions in an epidemic
  model

abstract:
  In epidemiological modelling, dynamics on networks, and in particular
adaptive and heterogeneous networks have recently received much interest. Here
we present a detailed analysis of a previously proposed model that combines
heterogeneity in the individuals with adaptive rewiring of the network
structure in response to a disease. We show that in this model qualitative
changes in the dynamics occur in two phase transitions. In a macroscopic
description one of these corresponds to a local bifurcation whereas the other
one corresponds to a non-local heteroclinic bifurcation. This model thus
provides a rare example of a system where a phase transition is caused by a
non-local bifurcation, while both micro- and macro-level dynamics are
accessible to mathematical analysis. The bifurcation points mark the onset of a
behaviour that we call network inoculation. In the respective parameter region
exposure of the system to a pathogen will lead to an outbreak that collapses,
but leaves the network in a configuration where the disease cannot reinvade,
despite every agent returning to the susceptible class. We argue that this
behaviour and the associated phase transitions can be expected to occur in a
wide class of models of sufficient complexity.


title:
Grid Based Nonlinear Filtering Revisited: Recursive Estimation &
  Asymptotic Optimality

abstract:
  We revisit the development of grid based recursive approximate filtering of
general Markov processes in discrete time, partially observed in conditionally
Gaussian noise. The grid based filters considered rely on two types of state
quantization: The \textit{Markovian} type and the \textit{marginal} type. We
propose a set of novel, relaxed sufficient conditions, ensuring strong and
fully characterized pathwise convergence of these filters to the respective
MMSE state estimator. In particular, for marginal state quantizations, we
introduce the notion of \textit{conditional regularity of stochastic kernels},
which, to the best of our knowledge, constitutes the most relaxed condition
proposed, under which asymptotic optimality of the respective grid based
filters is guaranteed. Further, we extend our convergence results, including
filtering of bounded and continuous functionals of the state, as well as
recursive approximate state prediction. For both Markovian and marginal
quantizations, the whole development of the respective grid based filters
relies more on linear-algebraic techniques and less on measure theoretic
arguments, making the presentation considerably shorter and technically
simpler.

categories: math.ST cs.IT math.IT math.OC stat.ME stat.ML stat.TH


title: Thermodynamic properties of modified gravity theories

abstract:
  We review thermodynamic properties of modified gravity theories such as
$F(R)$ gravity and $f(T)$ gravity, where $R$ is the scalar curvature and $T$ is
the torsion scalar in teleparallelism. In particular, we explore the
equivalence between the equations of motion for modified gravity theories and
the Clausius relation in thermodynamics. In addition, thermodynamics of the
cosmological apparent horizon is investigated in $f(T)$ gravity. We show both
equilibrium and non-equilibrium descriptions of thermodynamics. It is
demonstrated that the second law of thermodynamics in the universe can be met
when the temperature of the outside of the apparent horizon is equivalent to
that of the inside of it.


title: Ground state properties of quantum Kagome ice hardcore bosons

abstract:
  We study the quantum Kagom\'e ice hardcore bosons, which corresponds to the
XY limit of quantum spin ice Hamiltonian. We estimate the values of the
zero-temperature thermodynamic quantities using the large-$S$ expansion. We
show that our semi-classical analysis is consistent with finite temperature
quantum Monte Carlo estimates.


title: Online Nonnegative Matrix Factorization with Outliers

abstract:
  We propose a unified and systematic framework for performing online
nonnegative matrix factorization in the presence of outliers. Our framework is
particularly suited to large-scale data. We propose two solvers based on
projected gradient descent and the alternating direction method of multipliers.
We prove that the sequence of objective values converges almost surely by
appealing to the quasi-martingale convergence theorem. We also show the
sequence of learned dictionaries converges to the set of stationary points of
the expected loss function almost surely. In addition, we extend our basic
problem formulation to various settings with different constraints and
regularizers. We also adapt the solvers and analyses to each setting. We
perform extensive experiments on both synthetic and real datasets. These
experiments demonstrate the computational efficiency and efficacy of our
algorithms on tasks such as (parts-based) basis learning, image denoising,
shadow removal and foreground-background separation.

categories: stat.ML cs.IT cs.LG math.IT math.OC stat.ME


title:
Convex Floating Bodies as Approximations of Bergman Sublevel Sets on
  Tube Domains

abstract:
  For a pseudoconvex tube domain, we prove estimates that relate the sublevel
sets of its diagonal Bergman kernel to the floating bodies of its convex base.
This allows us to associate a new affine invariant to any convex body.


title:
Separation Framework: An Enabler for Cooperative and D2D Communication
  for Future 5G Networks

abstract:
  Soaring capacity and coverage demands dictate that future cellular networks
need to soon migrate towards ultra-dense networks. However, network
densification comes with a host of challenges that include compromised energy
efficiency, complex interference management, cumbersome mobility management,
burdensome signaling overheads and higher backhaul costs. Interestingly, most
of the problems, that beleaguer network densification, stem from legacy
networks' one common feature i.e., tight coupling between the control and data
planes regardless of their degree of heterogeneity and cell density.
Consequently, in wake of 5G, control and data planes separation architecture
(SARC) has recently been conceived as a promising paradigm that has potential
to address most of aforementioned challenges. In this article, we review
various proposals that have been presented in literature so far to enable SARC.
More specifically, we analyze how and to what degree various SARC proposals
address the four main challenges in network densification namely: energy
efficiency, system level capacity maximization, interference management and
mobility management. We then focus on two salient features of future cellular
networks that have not yet been adapted in legacy networks at wide scale and
thus remain a hallmark of 5G, i.e., coordinated multipoint (CoMP), and
device-to-device (D2D) communications. After providing necessary background on
CoMP and D2D, we analyze how SARC can particularly act as a major enabler for
CoMP and D2D in context of 5G. This article thus serves as both a tutorial as
well as an up to date survey on SARC, CoMP and D2D. Most importantly, the
article provides an extensive outlook of challenges and opportunities that lie
at the crossroads of these three mutually entangled emerging technologies.


title: A harmonic maps approach to fluid flows

abstract:
  We obtain a complete solution to the problem of classifying all
two-dimensional ideal fluid flows with harmonic Lagrangian labelling maps;
thus, we explicitly provide all solutions, with the specified structural
property, to the incompressible two-dimensional Euler equations (in Lagrangian
variables).


title: Totally Rank One Interval Exchange Transformations

abstract:
  For irreducible interval exchange transformations, we study the relation
between the powers of induced map and the induced maps of powers and raise a
condition of equivalence between them. And skew production of Rauzy induction
map is set up and verified to be ergodic regard to a product measure. Then we
prove that almost all the interval exchange transformations are totally rank
one (rank one for all powers of positive integers) by interval. As a corollary,
for almost all interval exchange transformations, rank one transformations are
dense $G_{\delta}$ in the weak closure.


title: Disciplined Convex-Concave Programming

abstract:
  In this paper we introduce disciplined convex-concave programming (DCCP),
which combines the ideas of disciplined convex programming (DCP) with
convex-concave programming (CCP). Convex-concave programming is an organized
heuristic for solving nonconvex problems that involve objective and constraint
functions that are a sum of a convex and a concave term. DCP is a structured
way to define convex optimization problems, based on a family of basic convex
and concave functions and a few rules for combining them. Problems expressed
using DCP can be automatically converted to standard form and solved by a
generic solver; widely used implementations include YALMIP, CVX, CVXPY, and
Convex.jl. In this paper we propose a framework that combines the two ideas,
and includes two improvements over previously published work on convex-concave
programming, specifically the handling of domains of the functions, and the
issue of nondifferentiability on the boundary of the domains. We describe a
Python implementation called DCCP, which extends CVXPY, and give examples.


title:
Inherently Unstable Internal Gravity Waves due to Resonant Harmonic
  Generation

abstract:
  Here we show that there exist internal gravity waves that are inherently
unstable, that is, they cannot exist in nature for a long time. The instability
mechanism is a one-way (irreversible) harmonic-generation resonance that
permanently transfers the energy of an internal wave to its higher harmonics.
We show that, in fact, there are countably infinite number of such unstable
waves. For the harmonic-generation resonance to take place, nonlinear terms in
the free surface boundary condition play a pivotal role, and the instability
does not obtain for a linearly-stratified fluid if a simplified boundary
condition such as rigid lid or linear form is employed. Harmonic-generation
resonance presented here also provides a mechanism for the transfer of the
energy of the internal waves to the higher-frequency part of the spectrum where
internal waves are more prone to breaking, hence losing energy to turbulence
and heat and contributing to oceanic mixing.


title:
Sensitivity of Internal Wave Energy Distribution over Seabed
  Corrugations to Adjacent Seabed Features

abstract:
  Here we show that the distribution of internal gravity waves energy over a
patch of seabed corrugations strongly depends on the "distance" of the patch to
adjacent seafloor features. Specifically, we consider the energy distribution
over a patch of seabed ripples neighbored to i. another patch of ripples, and
ii. a vertical wall. Seabed undulations with dominant wavenumber twice as large
as overpassing internal waves reflect back part of the energy of the internal
waves (Bragg reflection), let the rest of the energy to transmit or to be
transferred to higher and lower modes. In the presence of a neighboring
topography on the downstream side, the transmitted energy from the patch may
reflect back, e.g. partially if the downstream topography is another set of
seabed ripples, or fully if it is a vertical wall. The reflected wave from
downstream topography is again reflected back by the patch of ripples through
the same mechanism. This consecutive reflection goes on indefinitely leading to
a complex interaction pattern including constructive and destructive
interference of multiply reflected waves as well as an interplay between higher
modes internal waves resonated over the topography. We show here that when
steady state is reached both the qualitative and quantitative behavior of
energy distribution over the patch is a strong function of the "distance"
between the patch and the downstream topography. As a result, for instance, the
local energy density in the water column can become an order of magnitude
larger in certain areas merely based on where the downstream topography is.
This may result in the formation of steep waves in specific areas of the ocean,
leading to breaking and enhanced mixing. At a right distance, the wall or the
second patch may also result in a complete disappearance of the trace of the
seabed undulations on the upstream and the downstream wave field.


title: Program Evaluation with Right-Censored Data

abstract:
  In a unified framework, we provide estimators and confidence bands for a
variety of treatment effects when the outcome of interest, typically a
duration, is subjected to right censoring. Our methodology accommodates
average, distributional, and quantile treatment effects under different
identifying assumptions including unconfoundedness, local treatment effects,
and nonlinear differences-in-differences. The proposed estimators are easy to
implement, have close-form representation, are fully data-driven upon
estimation of nuisance parameters, and do not rely on parametric distributional
assumptions, shape restrictions, or on restricting the potential treatment
effect heterogeneity across different subpopulations. These treatment effects
results are obtained as a consequence of more general results on two-step
Kaplan-Meier estimators that are of independent interest: we provide conditions
for applying (i) uniform law of large numbers, (ii) functional central limit
theorems, and (iii) we prove the validity of the ordinary nonparametric
bootstrap in a two-step estimation procedure where the outcome of interest may
be randomly censored.


title:
Quasi-periodic oscillations as a tool for testing the Kerr metric: A
  comparison with gravitational waves and iron line

abstract:
  QPOs are a common feature in the X-ray power density spectrum of black hole
binaries and a potentially powerful tool to probe the spacetime geometry around
these objects. Here we discuss their constraining power to test the Kerr black
hole hypothesis within the relativistic precession model. We compare our
results with the constraints that can be obtained from gravitational waves and
iron line. We find that QPOs may provide very precise measurements, but they
are strongly affected by parameter degeneracy, and it is difficult to test the
Kerr metric with this approach in the absence of independent observations to
constrain the mass or the spin.


title:
Exponential Order Statistics, the Basel problem and Combinatorial
  Identities

abstract:
  We consider the k-th order statistic from unit exponential distribution and
show that it can be represented as a sum of independent exponential random
variables. Our proof is simple and different. It readily proves that the
standardized exponential spacings also follow unit exponential distribution. An
interesting probabilistic proof of the Basel problem is also given. Another
advantage of our approach is that by computing the Laplace transform of the
k-th order statistic in two different ways, we derive several interesting
combinatorial identities. A probabilistic interpretation of these identities
and their generalizations are also given.


title:
Hypothesis testing of the drift parameter sign for fractional
  Ornstein-Uhlenbeck process

abstract:
  We consider the fractional Ornstein-Uhlenbeck process with an unknown drift
parameter and known Hurst parameter $H$. We propose a new method to test the
hypothesis of the sign of the parameter and prove the consistency of the test.
Contrary to the previous works, our approach is applicable for all $H\in(0,1)$.
We also study the estimators for drift parameter for continuous and discrete
observations and prove their strong consistency for all $H\in(0,1)$.


title: Visualization Regularizers for Neural Network based Image Recognition

abstract:
  The success of deep neural networks is mostly due their ability to learn
meaningful features from the data. Features learned in the hidden layers of
deep neural networks trained in computer vision tasks have been shown to be
similar to mid-level vision features. We leverage this fact in this work and
propose the visualization regularizer for image tasks. The proposed
regularization technique enforces smoothness of the features learned by hidden
nodes and turns out to be a special case of Tikhonov regularization. We achieve
higher classification accuracy as compared to existing regularizers such as the
L2 norm regularizer and dropout, on benchmark datasets without changing the
training computational complexity.


title: Real-Time Facial Segmentation and Performance Capture from RGB Input

abstract:
  We introduce the concept of unconstrained real-time 3D facial performance
capture through explicit semantic segmentation in the RGB input. To ensure
robustness, cutting edge supervised learning approaches rely on large training
datasets of face images captured in the wild. While impressive tracking quality
has been demonstrated for faces that are largely visible, any occlusion due to
hair, accessories, or hand-to-face gestures would result in significant visual
artifacts and loss of tracking accuracy. The modeling of occlusions has been
mostly avoided due to its immense space of appearance variability. To address
this curse of high dimensionality, we perform tracking in unconstrained images
assuming non-face regions can be fully masked out. Along with recent
breakthroughs in deep learning, we demonstrate that pixel-level facial
segmentation is possible in real-time by repurposing convolutional neural
networks designed originally for general semantic segmentation. We develop an
efficient architecture based on a two-stream deconvolution network with
complementary characteristics, and introduce carefully designed training
samples and data augmentation strategies for improved segmentation accuracy and
robustness. We adopt a state-of-the-art regression-based facial tracking
framework with segmented face images as training, and demonstrate accurate and
uninterrupted facial performance capture in the presence of extreme occlusion
and even side views. Furthermore, the resulting segmentation can be directly
used to composite partial 3D face models on the input images and enable
seamless facial manipulation tasks, such as virtual make-up or face
replacement.


title: The singular set of triholomorphic maps into quartic K3 surface

abstract:
  We prove that any weakly triholomorphic map from a compact hyperk\"ahler
surface to an algebraic K3 surface defined by a homogeneous polynomial of
degree 4 in $\mathbb{C}P^3$ has only isolated singularities.


title: Bounds for the radii of univalence of some special functions

abstract:
  Tight lower and upper bounds for the radius of univalence of some normalized
Bessel, Struve and Lommel functions of the first kind are obtained via
Euler-Rayleigh inequalities. It is shown also that the radius of univalence of
the Struve functions is greater than the corresponding radius of univalence of
Bessel functions. Moreover, by using the idea of Kreyszig and Todd, and Wilf it
is proved that the radii of univalence of some normalized Struve and Lommel
functions are exactly the radii of starlikeness of the same functions. The
Laguerre-P\'olya class of entire functions plays an important role in our
study.


title:
Alignment and characterization of the two-stage time delay compensating
  XUV monochromator

abstract:
  We present the design, implementation and alignment procedure for a two-stage
time delay compensating monochromator. The setup spectrally filters the
radiation of a high-order harmonic generation source providing
wavelength-selected XUV pulses with a bandwidth of 300 to 600~meV in the photon
energy range of 3 to 50~eV. XUV pulses as short as $12\pm3$~fs are
demonstrated. Transmission of the 400~nm (3.1~eV) light facilitates precise
alignment of the monochromator. This alignment strategy together with the
stable mechanical design of the motorized beamline components enables us to
automatically scan the XUV photon energ in pump-probe experiments that require
XUV beam pointing stability. The performance of the beamline is demonstrated by
the generation of IR-assisted sidebands in XUV photoionization of argon atoms.


title: Relativistic Kinematics

abstract:
  This lecture note covers Relativistic Kinematics, which is very useful for
the beginners in the field of high-energy physics. A very practical approach
has been taken, which answers "why and how" of the kinematics useful for
students working in the related areas.


title: Hypergraphs in the characterization of regular vine copula structures

abstract:
  Vine copulas constitute a flexible way for modeling of dependences using only
pair copulas as building blocks. The pair-copula constructions introduced by
Joe (1997) are able to encode more types of dependences in the same time since
they can be expressed as a product of different types of bi-variate copulas.
The Regular-vine structures (R-vines), as pair copulas corresponding to a
sequence of trees, have been introduced by Bedford and Cooke (2001, 2002) and
further explored by Kurowicka and Cooke (2006). The complexity of these models
strongly increases in larger dimensions. Therefore the so called truncated
R-vines were introduced in Brechmann et al. (2012). In this paper we express
the Regular-vines using a special type of hypergraphs, which encodes the
conditional independences.


title:
Modified cumulative distribution function in application to waiting time
  analysis in CTRW scenario

abstract:
  The continuous time random walk model plays an important role in modeling of
so called anomalous diffusion behaviour. One of the specific property of such
model are constant time periods visible in trajectory. In the continuous time
random walk approach they are realizations of the sequence called waiting
times. The main attention of the paper is paid on the analysis of waiting times
distribution. We introduce here novel methods of estimation and statistical
investigation of such distribution. The methods are based on the modified
cumulative distribution function. In this paper we consider three special cases
of waiting time distributions, namely $\alpha$-stable, tempered stable and
gamma. However the proposed methodology can be applied to broad set of
distributions - in general it may serve as a method of fitting any distribution
function if the observations are rounded. The new statistical techniques we
apply to the simulated data as well as to the real data describing $CO_2$
concentration in indoor air.


title:
Exploring modular forms and the cohomology of local systems on moduli
  spaces by counting points

abstract:
  This is a report on a joint project in experimental mathematics with Jonas
Bergstr\"om and Carel Faber where we obtain information about modular forms by
counting curves over finite fields.


title: Nonlocal Correlation in Heisenberg Spin Models

abstract:
  In this paper we investigate the nonlocal correlation (beyond entanglement)
captured by measurement induced nonlocality and geometric quantum discord for a
pair of interacting spin-1/2 particles at thermal equilibrium. It is shown that
both the measures are identical in measuring the correlation. We show the
possibility of nonlocal correlation between the spins without entanglement,
which ceases to exist only for the maximal mixture of product bases. We also
observe that while interaction between the spins is responsible for the
enhancement of correlation, this non-classicality decreases with the
intervention of external magnetic field.


title:
Voyager Ultraviolet Spectrometers calibration and the heliosphere
  neutrals composition: reassessment

abstract:
  The Voyagers (V) 1 and 2 Ultraviolet Spectrometers (UVS) data harvest covers
outer planets encounters, heliosphere sky-background measurements, and stellar
spectrophotometry. Because their operation period overlaps with many
ultraviolet missions, the V1 and V2 UVS calibration with other spectrometers
are invaluable. Here we revisit the UVS calibration to assess the intriguing
243 % (V1) and 156 % (V2) sensitivity enhancements recently proposed. Using the
Saturn Lyman-$\alpha$ airglow, observed in-situ by both Voyagers, and remotely
by IUE, we match the Voyager values to IUE, taking into account the shape of
the Saturn Lyman-$\alpha$ line observed with the Goddard High Resolution
Spectrograph onboard the Hubble Space Telescope. For all known ranges of the
interplanetary hydrogen density, we show that the V1 and V2 UVS sensitivities
cannot be enhanced by the amounts thus far proposed. The same diagnostic holds
for distinct channels covering the diffuse HeI 58.4 nm emission. Our
prescription is to keep the original calibration of the Voyager UVS with a
maximum uncertainty of 30 %, making both instruments some of the most stable
EUV/FUV spectrographs of the history of space exploration. In that frame, we
reassess the Lyman-$\alpha$ emission excess detected by Voyager UVS deep in the
heliosphere, to show its consistency with the heliospheric but not the galactic
origin. Our finding confirms results obtained nearly two decades ago--namely,
the UVS discovery of the heliosphere distortion and the corresponding local
interstellar magnetic field's obliquity ($\sim40^{\circ}$ from upwind) in the
solar system neighborhood-- without requiring any revision of the Voyager UVS
calibration.


title: Direction matters: hand pose estimation from local surface normals

abstract:
  We present a hierarchical regression framework for estimating hand joint
positions from single depth images based on local surface normals. The
hierarchical regression follows the tree structured topology of hand from wrist
to finger tips. We propose a conditional regression forest, i.e., the Frame
Conditioned Regression Forest (FCRF) which uses a new normal difference
feature. At each stage of the regression, the frame of reference is established
from either the local surface normal or previously estimated hand joints. By
making the regression with respect to the local frame, the pose estimation is
more robust to rigid transformations. We also introduce a new efficient
approximation to estimate surface normals. We verify the effectiveness of our
method by conducting experiments on two challenging real-world datasets and
show consistent improvements over previous discriminative pose estimation
methods.


title: Sum Rules for Leptons

abstract:
  There is a wide class of models which give a dynamical description of the
origin of flavour in terms of spontaneous symmetry breaking of an underlying
symmetry. Many of these models exhibit sum rules which relate on the one hand
mixing angles and the Dirac CP phase with each other and/or on the other hand
neutrino masses and Majorana phases with each other. We will briefly sketch how
this happens and discuss briefly the impact of renormalisation group
corrections to the mass sum rules.


title: Sub-Nyquist Cyclostationary Detection for Cognitive Radio

abstract:
  Cognitive Radio requires efficient and reliable spectrum sensing of wideband
signals. In order to cope with the sampling rate bottleneck, new sampling
methods have been proposed that sample below the Nyquist rate. However, such
techniques decrease the signal to noise ratio (SNR), deteriorating the
performance of subsequent energy detection. Cyclostationary detection, which
exploits the periodic property of communication signal statistics, absent in
stationary noise, is a natural candidate for this setting. In this work, we
consider cyclic spectrum recovery from sub-Nyquist samples, in order to achieve
both efficiency and robustness to noise. To that end, we propose a structured
compressed sensing algorithm, that extends orthogonal matching pursuit to
account for the structure imposed by cyclostationarity. Next, we derive a lower
bound on the sampling rate required for perfect cyclic spectrum recovery in the
presence of stationary noise and show that it can be reconstructed from samples
obtained below Nyquist, without any sparsity constraints on the signal. In
particular, in non sparse settings, the cyclic spectrum can be recovered at
$4/5$ of the Nyquist rate. If the signal of interest is sparse, then the
sampling rate may be further reduced to $8/5$ of the Landau rate. Once the
cyclic spectrum is recovered, we estimate the number of transmissions that
compose the input signal, along with their carrier frequencies and bandwidths.
Simulations show that cyclostationary detection outperforms energy detection in
low SNRs in the sub-Nyquist regime. This was already known in the Nyquist
regime, but is even more pronounced at sub-Nyquist sampling rates.


title: Vehicular Communications for 5G Cooperative Small Cell Networks

abstract:
  The cooperative transmission is an effective approach for vehicular
communications to improve the wireless transmission capacity and reliability in
the fifth generation (5G) small cell networks. Based on distances between the
vehicle and cooperative small cell BSs, the cooperative probability and the
coverage probability have been derived for 5G cooperative small cell networks
where small cell base stations (BSs) follow Poisson point process
distributions. Furthermore, the vehicular handoff rate and the vehicular
overhead ratio have been proposed to evaluate the vehicular mobility
performance in 5G cooperative small cell networks. To balance the vehicular
communication capacity and the vehicular handoff ratio, an optimal vehicular
overhead ratio can be achieved by adjusting the cooperative threshold of 5G
cooperative small cell networks.


title:
Characterising the rotational irregularities of the Vela pulsar from 21
  yr of phase-coherent timing

abstract:
  Pulsars show two classes of rotational irregularities that can be used to
understand neutron-star interiors and magnetospheres: glitches and timing
noise. Here we present an analysis of the Vela pulsar spanning nearly 21 yr of
observation and including 8 glitches. We identify the relative pulse number of
all of the observations between glitches, with the only pulse-number
ambiguities existing over glitch events. We use the phase coherence of the
timing solution to simultaneously model the timing noise and glitches in a
Bayesian framework, allowing us to select preferred models for both. We find
the glitches can be described using only permanent and transient changes in
spin frequency, i.e., no step changes in frequency derivative. For all of the
glitches, we only need two exponentially decaying changes in spin frequency to
model the transient components. In contrast to previous studies, we find that
the dominant transient components decay on a common $\approx$ 1300 d time
scale, and that a larger fraction ( $\gtrsim 25\%$) of glitch amplitudes are
associated with these transient components. We also detect shorter-duration
transient components of $\approx$ 25 d, as previously observed, but are limited
in sensitivity to events with shorter durations by the cadence of our
observations. The timing noise is well described by a steep power-law process
that is independent of the glitches and subdominant to the glitch recovery. The
braking index is constrained to be $<$ 8 with 95% confidence. This methodology
can be used to robustly measure the properties of glitches and timing noise in
other pulsars.


title: In Search of a Pristine Signal for (Scale-)Chiral Symmetry in Nuclei

abstract:
  I describe the long-standing search for a "smoking-gun" signal for the
manifestation of (scale-)chiral symmetry in nuclear interactions. It is
prompted by Gerry Brown's last unpublished note, reproduced verbatim below, on
the preeminent role of pions and vector ($\rho$,$\omega$) mesons in providing a
simple and elegant description of strongly correlated nuclear interactions. In
this note written in tribute to Gerry Brown, I first describe a case of an
unambiguous signal in axial-charge transitions in nuclei and then combine his
ideas with the more recent development on the role of hidden symmetries in
nuclear physics. What transpires is the surprising conclusion that the
Landau-Migdal fixed point interaction $G_0^\prime$, the nuclear tensor forces
and Brown-Rho scaling, all encoded in scale-invariant hidden local symmetry, as
Gerry put, "run the show and make all forces equal."


title: Drag cancellation by added-mass pumping

abstract:
  A submerged body subject to a sudden shape-change experiences large forces
due to the variation of added-mass energy. While this phenomenon has been
studied for single actuation events, application to sustained propulsion
requires studying \textit{periodic} shape-change. We do so in this work by
investigating a spring-mass oscillator submerged in quiescent fluid subject to
periodic changes in its volume. We develop an analytical model to investigate
the relationship between added-mass variation and viscous damping and
demonstrate its range of application with fully coupled fluid-solid
Navier-Stokes simulations at large Stokes number. Our results demonstrate that
the recovery of added-mass kinetic energy can be used to completely cancel the
viscous damping of the fluid, driving the onset of sustained oscillations with
amplitudes as large as four times the average body radius $r_0$. A quasi-linear
relationship is found to link the terminal amplitude of the oscillations $X$,
to the extent of size change $a$, with $X/a$ peaking at values from 4 to 4.75
depending on the details of the shape-change kinematics. In addition, it is
found that pumping in the frequency range of
$1-\frac{a}{2r_0}<\omega^2/\omega_n^2<1+\frac{a}{2r_0}$ is required for
sustained oscillations. The results of this analysis shed light on the role of
added-mass recovery in the context of shape-changing bodies and
biologically-inspired underwater vehicles.


title:
Inelastic vibrational signals in electron transport across graphene
  nanoconstrictions

abstract:
  We present calculations of the inelastic vibrational signals in the
electrical current through a graphene nanoconstriction. We find that the
inelastic signals are only present when the Fermi-level position is tuned to
electron transmission resonances, thus, providing a fingerprint which can link
an electron transmission resonance to originate from the nanoconstriction. The
calculations are based on a novel first-principles method which includes the
phonon broadening due to coupling with phonons in the electrodes. We find that
the signals are modified due to the strong coupling to the electrodes, however,
still remain as robust fingerprints of the vibrations in the nanoconstriction.
We investigate the effect of including the full self-consistent potential drop
due to finite bias and gate doping on the calculations and find this to be of
minor importance.


title: Energy Efficiency Optimization of 5G Radio Frequency Chain Systems

abstract:
  With the massive multi-input multi-output (MIMO) antennas technology adopted
for the fifth generation (5G) wireless communication systems, a large number of
radio frequency (RF) chains have to be employed for RF circuits. However, a
large number of RF chains not only increase the cost of RF circuits but also
consume additional energy in 5G wireless communication systems. In this paper
we investigate energy and cost efficiency optimization solutions for 5G
wireless communication systems with a large number of antennas and RF chains.
An energy efficiency optimization problem is formulated for 5G wireless
communication systems using massive MIMO antennas and millimeter wave
technology. Considering the nonconcave feature of the objective function, a
suboptimal iterative algorithm, i.e., the energy efficient hybrid precoding
(EEHP) algorithm is developed for maximizing the energy efficiency of 5G
wireless communication systems. To reduce the cost of RF circuits, the energy
efficient hybrid precoding with the minimum number of RF chains (EEHP-MRFC)
algorithm is also proposed. Moreover, the critical number of antennas searching
(CNAS) and user equipment number optimization (UENO) algorithms are further
developed to optimize the energy efficiency of 5G wireless communication
systems by the number of transmit antennas and UEs. Compared with the maximum
energy efficiency of conventional zero-forcing (ZF) precoding algorithm,
numerical results indicate that the maximum energy efficiency of the proposed
EEHP and EEHP-MRFC algorithms are improved by 220% and 171%, respectively.


title: Oscillate Boiling

abstract:
  We report about an intriguing boiling regime occurring for small heaters
embedded on the boundary in subcooled water. The microheater is realized by
focusing a continuous wave laser beam to about $10\,\mu$m in diameter onto a
165\,nm-thick layer of gold, which is submerged in water. After an initial
vaporous explosion a single bubble oscillates continuously and repeatably at
several $100\,$kHz. The microbubble's oscillations are accompanied with bubble
pinch-off leading to a stream of gaseous bubbles into the subcooled water. The
self-driven bubble oscillation is explained with a thermally kicked oscillator
caused by the non-spherical collapses and by surface pinning. Additionally,
Marangoni stresses induce a recirculating streaming flow which transports cold
liquid towards the microheater reducing diffusion of heat along the substrate
and therefore stabilizing the phenomenon to many million cycles. We speculate
that this oscillate boiling regime may allow to overcome the heat transfer
thresholds observed during the nucleate boiling crisis and offers a new pathway
for heat transfer under microgravity conditions.


title: Non--analytic terms from nested divergences in maximal supergravity

abstract:
  The $D^4\mathcal{R}^4$ and $D^6\mathcal{R}^4$ coefficient functions in the
effective action of type II string theory compactified on $T^d$ contain terms
of the form $\mathcal{E}_1 {\rm ln}g_d$ and $\mathcal{E}_2 ({\rm ln}g_d)^2$ in
specific dimensions, where $g_d$ is the T--duality invariant string coupling,
and $\mathcal{E}_1$ and $\mathcal{E}_2$ are U--duality invariant coefficient
functions. We derive these non--analytic terms from nested ultraviolet
divergences in two and three loop maximal supergravity. For the
$D^4\mathcal{R}^4$ coupling, the contribution involves
$\mathcal{E}_{\mathcal{R}^4} {\rm ln} g_d$, while for the $D^6\mathcal{R}^4$
coupling, it involves $\mathcal{E}_{\mathcal{R}^4} {\rm ln} g_d$,
$\mathcal{E}_{D^2\mathcal{R}^4} ({\rm ln} g_d)^2$ and
$\mathcal{E}_{D^4\mathcal{R}^4} {\rm ln} g_d$; where
$\mathcal{E}_{\mathcal{R}^4}$, $\mathcal{E}_{D^2\mathcal{R}^4}$ and
$\mathcal{E}_{D^4\mathcal{R}^4}$ are the $\mathcal{R}^4$, $D^2\mathcal{R}^4$
and $D^4\mathcal{R}^4$ coefficient functions respectively. The contribution
from $\mathcal{E}_{D^2\mathcal{R}^4}$, the coefficient function of an amplitude
that vanishes onshell, arises from a two loop nested subdivergence of the three
loop amplitude.


title:
Distance for Functional Data Clustering Based on Smoothing Parameter
  Commutation

abstract:
  We propose a novel method to determine the dissimilarity between subjects for
functional data clustering. Spline smoothing or interpolation is common to deal
with data of such type. Instead of estimating the best-representing curve for
each subject as fixed during clustering, we measure the dissimilarity between
subjects based on varying curve estimates with commutation of smoothing
parameters pair-by-pair (of subjects). The intuitions are that smoothing
parameters of smoothing splines reflect inverse signal-to-noise ratios and that
applying an identical smoothing parameter the smoothed curves for two similar
subjects are expected to be close. The effectiveness of our proposal is shown
through simulations comparing to other dissimilarity measures. It also has
several pragmatic advantages. First, missing values or irregular time points
can be handled directly, thanks to the nature of smoothing splines. Second,
conventional clustering method based on dissimilarity can be employed
straightforward, and the dissimilarity also serves as a useful tool for outlier
detection. Third, the implementation is almost handy since subroutines for
smoothing splines and numerical integration are widely available. Fourth, the
computational complexity does not increase and is parallel with that in
calculating Euclidean distance between curves estimated by smoothing splines.


title:
FG-coupled fixed point theorems for contractive and generalized
  quasi-contractive mappings

abstract:
  In this paper we prove FG-coupled fixed point theorems for different
contractive mappings and generalized quasi- contractive mappings in partially
ordered complete metric spaces. We prove the existence of FG-coupled fixed
points of continuous as well as discontinuous mappings. We give some examples
to illustrate the results.


title:
Numerical test of the method for revealing traces of deterministic chaos
  in the accreting black holes

abstract:
  The high energy radiation emitted by black hole X-ray binaries originates in
an accretion disk, hence the variability of the lightcurves mirrors the
dynamics of the disc. We study the time evolution of the emitted flux in order
to find evidences, that low dimensional non-linear equations govern the
accretion flow. Here we test the capabilities of our novel method to find
chaotic behaviour on the two numerical time series describing the motion of a
test particle around a black hole surrounded by a thin massive disc, one being
regular and the other one chaotic.


title: Computational Complex Dynamics Of The Discrete Lorenz System

abstract:
  The dynamics of the classical Lorenz system is well studied in $1963$ by E.
N. Lorenz. Later on, there have been an extensive studies on the classical
Lorenz system with the complex variables and the discrete time Lorenz system
with real variables. To the best of knowledge of the author, so far there is no
study on discrete time Lorenz system in complex variables. In this article, an
attempt has been made to observe and understand the discrete dynamics of the
Lorenz system with complex variables. This study compares the discrete dynamics
of the Lorenz system with complex variables to that of the classical Lorenz
system involving real and complex variables.


title: On non-maximal prime ideals of $C[0,1]$

abstract:
  We first show a counter intuitive result that in the ring of real valued
continuous functions on $[0,1]$ non maximal prime ideals exist. This is a
standard proof and a well known result. Interestingly, a non maximal prime
ideal in this ring is actually contained inside a unique maximal ideal. We
arrive at this result merely by looking at the zero set of ideals in this ring
and by making simple geometrical observations. We end by leaving the reader
with an interesting open problem that logically follows from this article.


title: Rectifiability of non Euclidean planar self-contracted curves

abstract:
  We prove that any self-contracted curve in R 2 endowed with a C 2 and
strictly convex norm, has finite length. The proof follows from the study of
the curve bisector of two points in R 2 for a general norm together with an
adaptation of the argument used in [2].


title:
Construction of Willmore two-spheres via harmonic maps into
  $SO^+(1,n+3)/(SO^+(1,1)\times SO(n+2))$

abstract:
  This paper aims to provide a description of totally isotropic Willmore
two-spheres and their adjoint transforms. We first recall the isotropic
harmonic maps which are introduced by H\'elein, Xia-Shen and Ma for the study
of Willmore surfaces. Then we derive a description of the normalized potential
(some Lie algebra valued meromorphic 1-forms) of totally isotropic Willmore
two-spheres in terms of the isotropic harmonic maps. In particular, the
corresponding isotropic harmonic maps are of finite uniton type. The proof also
contains a concrete way to construct examples of totally isotropic Willmore
two-spheres and their adjoint transforms. As illustrations, two kinds of
examples are obtained this way.


title:
Further results on generalized inverses of tensors via the Einstein
  product

abstract:
  The notion of the Moore-Penrose inverse of tensors with the Einstein product
was introduced, very recently. In this paper, we further elaborate this theory
by producing a few characterizations of different generalized inverses of
tensors. A new method to compute the Moore-Penrose inverse of tensors is
proposed. Reverse order laws for several generalized inverses of tensors are
also presented. In addition to these, we discuss general solutions of
multilinear systems of tensors using such theory.


title: Approximating Nash Equilibria in Tree Polymatrix Games

abstract:
  We develop a quasi-polynomial time Las Vegas algorithm for approximating Nash
equilibria in polymatrix games over trees, under a mild renormalizing
assumption. Our result, in particular, leads to an expected polynomial-time
algorithm for computing approximate Nash equilibria of tree polymatrix games in
which the number of actions per player is a fixed constant. Further, for trees
with constant degree, the running time of the algorithm matches the best known
upper bound for approximating Nash equilibria in bimatrix games (Lipton,
Markakis, and Mehta 2003).
  Notably, this work closely complements the hardness result of Rubinstein
(2015), which establishes the inapproximability of Nash equilibria in
polymatrix games over constant-degree bipartite graphs with two actions per
player.


title: DCAN: Deep Contour-Aware Networks for Accurate Gland Segmentation

abstract:
  The morphology of glands has been used routinely by pathologists to assess
the malignancy degree of adenocarcinomas. Accurate segmentation of glands from
histology images is a crucial step to obtain reliable morphological statistics
for quantitative diagnosis. In this paper, we proposed an efficient deep
contour-aware network (DCAN) to solve this challenging problem under a unified
multi-task learning framework. In the proposed network, multi-level contextual
features from the hierarchical architecture are explored with auxiliary
supervision for accurate gland segmentation. When incorporated with multi-task
regularization during the training, the discriminative capability of
intermediate features can be further improved. Moreover, our network can not
only output accurate probability maps of glands, but also depict clear contours
simultaneously for separating clustered objects, which further boosts the gland
segmentation performance. This unified framework can be efficient when applied
to large-scale histopathological data without resorting to additional steps to
generate contours based on low-level cues for post-separating. Our method won
the 2015 MICCAI Gland Segmentation Challenge out of 13 competitive teams,
surpassing all the other methods by a significant margin.


title: Topological pressure of proper map

abstract:
  Based on the Carath\'eodory -Pesin structure theory[11], we introduce three
notions of topological pressure of a proper map and provide some properties of
these notions. For the proper map of a locally compact separable metric space,
we prove some variational principles and give some applications. These are the
extensions of results of Pesin, Takens and Verbiski, etc.


title: First Detection of $^3$He$^+$ in the Planetary Nebula IC$\,$418

abstract:
  The $^3$He isotope is important to many fields of astrophysics, including
stellar evolution, chemical evolution, and cosmology. The isotope is produced
in low-mass stars which evolve through the planetary nebula (PN) phase. $^3$He
abundances in PNe can help test models of the chemical evolution of the Galaxy.
We present the detection of the $^3$He$^+$ emission line using the single dish
Deep Space Station 63, towards the PN IC$\,$418. We derived a $^3$He/H
abundance in the range 1.74$\pm$0.8$\times$10$^{-3}$ to
5.8$\pm$1.7$\times$10$^{-3}$, depending on whether part of the line arises in
an outer ionized halo. The lower value for $^3$He/H ratio approaches values
predicted by stellar models which include thermohaline mixing, but requires
that large amounts of $^3$He are produced inside low-mass stars which enrich
the interstellar medium (ISM). However, this over-predicts the $^3$He abundance
in HII regions, the ISM, and proto-solar grains, which is known to be of the
order of 10$^{-5}$. This discrepancy questions our understanding of the
evolution of the $^3$He, from circumstellar environments to the ISM.


title:
Sub-Inertial Gravity Modes in the B8V Star KIC 7760680 Reveal Moderate
  Core Overshooting and Low Vertical Diffusive Mixing

abstract:
  KIC 7760680 is so far the richest slowly pulsating B star, by exhibiting 36
consecutive dipole ($\ell=1$) gravity (g-) modes. The monotonically decreasing
period spacing of the series, in addition to the local dips in the pattern
confirm that KIC 7760680 is a moderate rotator, with clear mode trapping in
chemically inhomogeneous layers. We employ the traditional approximation of
rotation to incorporate rotational effects on g-mode frequencies. Our detailed
forward asteroseismic modelling of this g-mode series reveals that KIC 7760680
is a moderately rotating B star with mass $\sim3.25$ M$_\odot$. By
simultaneously matching the slope of the period spacing, and the number of
modes in the observed frequency range, we deduce that the equatorial rotation
frequency of KIC 7760680 is 0.4805 day$^{-1}$, which is 26\% of its Roche break
up frequency. The relative deviation of the model frequencies and those
observed is less than one percent. We succeed to tightly constrain the
exponentially-decaying convective core overshooting parameter to $f_{\rm
ov}\approx0.024\pm0.001$. This means that convective core overshooting can
coexist with moderate rotation. Moreover, models with exponentially-decaying
overshoot from the core outperform those with the classical step-function
overshoot. The best value for extra diffusive mixing in the radiatively stable
envelope is confined to $\log D_{\rm ext}\approx0.75\pm0.25$ (with $D_{\rm
ext}$ in cm$^2$ sec$^{-1}$), which is notably smaller than theoretical
predictions.


title: Uniqueness of stable-like processes

abstract:
  In this work we consider the following $\alpha$-stable-like operator (a class
of pseudo-differential operator) $$ {\mathscr L} f(x):=\int_{\mathbb
R^d}[f(x+\sigma_x y)-f(x)-1_{\alpha\in[1,2)}1_{|y|\leq 1}\sigma_x y\cdot\nabla
f(x)]\nu_x(d y), $$ where the L\'evy measure $\nu_x(d y)$ is comparable with a
non-degenerate $\alpha$-stable-type L\'evy measure (possibly singular), and
$\sigma_x$ is a bounded and nondegenerate matrix-valued function. Under
H\"older assumption on $x\mapsto\nu_x(d y)$ and uniformly continuity assumption
on $x\mapsto\sigma_x$, we show the well-posedness of martingale problem
associated with the operator $\mathscr L$. Moreover, we also obtain the
existence-uniqueness of strong solutions for the associated SDE when $\sigma$
belongs to the first order Sobolev space $\mathbb W^{1,p}(\mathbb R^d)$
provided $p>d(1+\alpha\vee 1)$ and $\nu_x=\nu$ is a non-degenerate
$\alpha$-stable-type L\'evy measure.


title: The invertibility of 2X2 operator matrices

abstract:
  In this paper the properties of right invertible row operators, i.e., of 1X2
surjective operator matrices are studied. This investigation is based on a
specific space decomposition. Using this decomposition, we characterize the
invertibility of a 2X2 operator matrix. As an application, the invertibility of
Hamiltonian operator matrices is investigated.


title:
The Intensity Matching Approach: A Tractable Stochastic Geometry
  Approximation to System-Level Analysis of Cellular Networks

abstract:
  The intensity matching approach for tractable performance evaluation and
optimization of cellular networks is introduced. It assumes that the base
stations are modeled as points of a Poisson point process and leverages
stochastic geometry for system-level analysis. Its rationale relies on
observing that system-level performance is determined by the intensity measure
of transformations of the underlaying spatial Poisson point process. By
approximating the original system model with a simplified one, whose
performance is determined by a mathematically convenient intensity measure,
tractable yet accurate integral expressions for computing area spectral
efficiency and potential throughput are provided. The considered system model
accounts for many practical aspects that, for tractability, are typically
neglected, e.g., line-of-sight and non-line-of-sight propagation, antenna
radiation patterns, traffic load, practical cell associations, general fading
channels. The proposed approach, more importantly, is conveniently formulated
for unveiling the impact of several system parameters, e.g., the density of
base stations and blockages. The effectiveness of this novel and general
methodology is validated with the aid of empirical data for the locations of
base stations and for the footprints of buildings in dense urban environments.


title:
Periodic subvarieties of a projective variety under the action of a
  maximal rank abelian group of positive entropy

abstract:
  We determine positive-dimensional G-periodic proper subvarieties of an
n-dimensional normal projective variety X under the action of an abelian group
G of maximal rank n-1 and of positive entropy. The motivation of the paper is
to understand the obstruction for X to be G-equivariant birational to the
quotient variety of an abelian variety modulo the action of a finite group.


title: Measurement of spin coherence using Raman scattering

abstract:
  Ramsey interferometry provides a natural way to determine the coherence time
of most qubit systems. Recent experiments on quantum dots however, demonstrated
that dynamical nuclear spin polarization can strongly influence the measurement
process, making it difficult to extract the $T_2^*$ coherence time using
optical Ramsey pulses. Here, we demonstrate an alternative method for spin
coherence measurement that is based on first-order coherence of photons
generated in spin-flip Raman scattering. We show that if a quantum emitter is
driven by a weak monochromatic laser, Raman coherence is determined exclusively
by spin coherence, allowing for a direct determination of spin $T_2^*$ time.
When combined with coherence measurements on Rayleigh scattered photons, our
technique enables us to identify coherent and incoherent contributions to
resonance fluorescence, and to minimize the latter. We verify the validity of
our technique by comparing our results to those determined from Ramsey
interferometry for electron and heavy-hole spins.


title: Temperature dependence of elastocaloric effect in natural rubber

abstract:
  The temperature dependence of the elastocaloric (eC) effect in natural rubber
(NR) is studied adiabatically and isothermally. A broad temperature span for eC
effect from 0 oC to 49 oC is observed. The maximum adiabatic temperature change
({\Delta}T) is 12 K at strain of 6 and occurs at 10 oC. These behaviors can be
predicted by the temperature dependence of strain-induced crystallization (SIC)
and temperature-induced crystallization (TIC). In isothermal condition, the
deduced {\Delta}T from Clausius-Clapeyron factor can agree with the direct
measurement at different temperatures. The eC performance of NR is compared
with shape memory alloys (SMAs). The potential of NR for a near room
temperature cooing application is primarily proved. This will open the SIC
research of NR towards eC cooling direction.