title:
Local H\"older continuity of the isoperimetric profile in complete
  noncompact Riemannian manifolds with bounded geometry

abstract:
  For a complete noncompact connected Riemannian manifold with bounded geometry
$M^n$, we prove that the isoperimetric profile function $I_{M^n}$ is a locally
$\left(1-\frac{1}{n}\right)$-H\"older continuous function and so in particular
it is continuous. Here for bounded geometry we mean that $M$ have $Ricci$
curvature bounded below and volume of balls of radius $1$, uniformly bounded
below with respect to its centers. We prove also the equivalence of the weak
and strong formulation of the isoperimetric profile function in complete
Riemannian manifolds which is based on a lemma having its own interest about
the approximation of finite perimeter sets with finite volume by open bounded
with smooth boundary ones of the same volume. Finally the upper semicontinuity
of the isoperimetric profile for every metric (not necessarily complete) is
shown.


title: Functional Horseshoe Priors for Subspace Shrinkage

abstract:
  We introduce a new shrinkage prior on function spaces, called the functional
horseshoe prior (fHS), that encourages shrinkage towards parametric classes of
functions. Unlike other shrinkage priors for parametric models, the fHS
shrinkage acts on the shape of the function rather than inducing sparsity on
model parameters. We study the efficacy of the proposed approach by showing an
adaptive posterior concentration property on the function. We also demonstrate
consistency of the model selection procedure that thresholds the shrinkage
parameter of the functional horseshoe prior. We apply the fHS prior to
nonparametric additive models and compare its performance with procedures based
on the standard horseshoe prior and several penalized likelihood approaches. We
find that the new procedure achieves smaller estimation error and more accurate
model selection than other procedures in several simulated and real examples.
The supplementary material for this article, which contains additional
simulated and real data examples, MCMC diagnostics, and proofs of the
theoretical results, is available online.


title: Inversion Copulas from Nonlinear State Space Models

abstract:
  We propose to construct copulas from the inversion of nonlinear state space
models. These allow for new time series models that have the same serial
dependence structure of a state space model, but with an arbitrary marginal
distribution, and flexible density forecasts. We examine the time series
properties of the copulas, outline serial dependence measures, and estimate the
models using likelihood-based methods. Copulas constructed from three example
state space models are considered: a stochastic volatility model with an
unobserved component, a Markov switching autoregression, and a Gaussian linear
unobserved component model. We show that all three inversion copulas with
flexible margins improve the fit and density forecasts of quarterly U.S. broad
inflation and electricity inflation.


title: Inscribed Matter Communication: Part I

abstract:
  We provide a fundamental treatment of the molecular communication channel
wherein "inscribed matter" is transmitted across a spatial gap to provide
reliable signaling between a sender and receiver. Inscribed matter is defined
as an ensemble of "tokens" (molecules, objects, and so on) and is inspired, at
least partially, by biological systems where groups of individually constructed
discrete particles ranging from molecules through membrane-bound structures
containing molecules to viruses and organisms are released by a source and
travel to a target -- for example, morphogens or semiochemicals diffuse from
one cell, tissue or organism diffuse to another. For identical tokens that are
neither lost nor modified, we consider messages encoded using three candidate
communication schemes: a) token timing (timed release), b) token payload
(composition), and c) token timing plus payload. We provide capacity bounds for
each scheme and discuss their relative utility. We find that under not
unreasonable assumptions, megabit per second rates could be supported at
femtoWatt transmitter powers. Since quantities such as token concentration or
bin-counting are derivatives of token arrival timing, individual token timing
undergirds all molecular communication techniques. Thus, our modeling and
results about the physics of efficient token-based information transfer can
inform investigations of diverse theoretical and practical problems in
engineering and biology. This work, Part I, focuses on the information
theoretic bounds on capacity. Part II develops some of the mathematical and
information-theoretic ideas that support the bounds presented here.


title:
Nonlinear light-Higgs coupling in superconductors beyond BCS: Effects of
  the retarded phonon-mediated interaction

abstract:
  We study the contribution of the Higgs amplitude mode on the nonlinear
optical response of superconductors beyond the BCS approximation by taking into
account the retardation effect in the phonon-mediated attractive interaction.
To evaluate the vertex correction in nonlinear optical susceptibilities that
contains the effect of collective modes, we propose an efficient scheme which
we call the "dotted DMFT" based on the nonequilibrium dynamical mean-field
theory (nonequilibrium DMFT) to go around the difficulty of solving the
Bethe-Salpeter equation and analytical continuation. The vertex correction is
represented by the derivative of the self-energy with respect to the external
driving field, which is self-consistently determined by the differentiated
("dotted") DMFT equations. We apply the method to the Holstein model, a
prototypical electron-phonon-coupled system, to calculate the susceptibility
for the third-harmonic generation including the vertex correction. The results
show that, in sharp contrast to the BCS theory, the Higgs mode can contribute
to the third-harmonic generation for general polarization of the laser field
with an order of magnitude comparable to the contribution from the pair
breaking or charge density fluctuations. The physical origin is traced back to
the nonlinear resonant light-Higgs coupling, which has been absent in the BCS
approximation.


title: Large Antenna Analysis of Multi-Cell Full-Duplex Networks

abstract:
  We study a multi-cell multi-user MIMO full-duplex network, where each base
station (BS) has multiple antennas with full-duplex capability supporting
single-antenna users with either full-duplex or half-duplex radios. We
characterize the up- and downlink ergodic achievable rates for the case of
linear precoders and receivers. The rate analysis includes practical
constraints such as imperfect self- interference cancellation, channel
estimation error, training overhead and pilot contamination. We show that the
2X gain of full-duplex over half-duplex system remains in the asymptotic regime
where the number of BS antennas grows infinitely large. We numerically evaluate
the finite SNR and antenna performance, which reveals that full-duplex networks
can use significantly fewer antennas to achieve spectral efficiency gain over
the half-duplex counterparts. In addition, the overall full-duplex gains can be
achieved under realistic 3GPP multi-cell network settings despite the increased
interference introduced in the full-duplex networks.


title: A direct proof of F. Riesz representation Theorem

abstract:
  A direct proof of the Riesz representation theorem is provided. This theorem
characterizes the linear functionals acting on the vector space $C(K)$ of
continuous functions defined on a compact subset $K$ of the real numbers
$\mathbb{R}$. This proof avoids complicated arguments commonly used in
generalizations of Riesz original theorem.


title: Learning Optimal Interventions

abstract:
  Our goal is to identify beneficial interventions from observational data. We
consider interventions that are narrowly focused (impacting few covariates) and
may be tailored to each individual or globally enacted over a population. For
applications where harmful intervention is drastically worse than proposing no
change, we propose a conservative definition of the optimal intervention.
Assuming the underlying relationship remains invariant under intervention, we
develop efficient algorithms to identify the optimal intervention policy from
limited data and provide theoretical guarantees for our approach in a Gaussian
Process setting. Although our methods assume covariates can be precisely
adjusted, they remain capable of improving outcomes in misspecified settings
where interventions incur unintentional downstream effects. Empirically, our
approach identifies good interventions in two practical applications: gene
perturbation and writing improvement.


title:
New variable stars discovered in the fields of three Galactic open
  clusters using the VVV Survey

abstract:
  This project is a massive near-infrared (NIR) search for variable stars in
highly reddened and obscured open cluster (OC) fields projected on regions of
the Galactic bulge and disk. The search is performed using photometric NIR data
in the $J$-, $H$- and $K_s$- bands obtained from the Vista Variables in the
V\'ia L\'actea (VVV) Survey. We performed in each cluster field a variability
search using Stetson's variability statistics to select the variable
candidates. Later, those candidates were subjected to a frequency analysis
using the Generalized Lomb-Scargle and the Phase Dispersion Minimization
algorithms. The number of independent observations range between 63 and 73. The
newly discovered variables in this study, 157 in total in three different known
OCs, are classified based on their light curve shapes, periods, amplitudes and
their location in the corresponding color-magnitude $(J-K_s,K_s)$ and
color-color $(H-K_s,J-H)$ diagrams. We found 5 possible Cepheid stars which,
based on the period-luminosity relation, are very likely type II Cepheids
located behind the bulge. Among the newly discovered variables, there are
eclipsing binaries, $\delta$ Scuti, as well as background RR Lyrae stars. Using
the new version of the Wilson & Devinney code as well as the "Physics Of
Eclipsing Binaries" (PHOEBE) code, we analyzed some of the best eclipsing
binaries we discovered. Our results show that these studied systems turn out to
be ranging from detached to double-contact binaries, with low eccentricities
and high inclinations of approximately $80^{\circ}$. Their surface temperatures
range between $3500$K and $8000$K.


title:
No Need to Pay Attention: Simple Recurrent Neural Networks Work! (for
  Answering "Simple" Questions)

abstract:
  First-order factoid question answering assumes that the question can be
answered by a single fact in a knowledge base (KB). While this does not seem
like a challenging task, many recent attempts that apply either complex
linguistic reasoning or deep neural networks achieve 65%-76% accuracy on
benchmark sets. Our approach formulates the task as two machine learning
problems: detecting the entities in the question, and classifying the question
as one of the relation types in the KB. We train a recurrent neural network to
solve each problem. On the SimpleQuestions dataset, our approach yields
substantial improvements over previously published results --- even neural
networks based on much more complex architectures. The simplicity of our
approach also has practical advantages, such as efficiency and modularity, that
are valuable especially in an industry setting. In fact, we present a
preliminary analysis of the performance of our model on real queries from
Comcast's X1 entertainment platform with millions of users every day.


title:
Minimization of Akaike's Information Criterion in Linear Regression
  Analysis via Mixed Integer Nonlinear Program

abstract:
  Akaike's information criterion (AIC) is a measure of the quality of a
statistical model for a given set of data. We can determine the best
statistical model for a particular data set by the minimization of the AIC.
Since we need to evaluate exponentially many candidates of the model by the
minimization of the AIC, the minimization is unreasonable. Instead, stepwise
methods, which are local search algorithms, are commonly used to find a better
statistical model though it may not be the best.
  We propose a branch and bound search algorithm for a mixed integer nonlinear
programming formulation of the AIC minimization by Miyashiro and Takano (2015).
More concretely, we propose methods to find lower and upper bounds, and
branching rules for this minimization. We then combine them with SCIP, which is
a mathematical optimization software and a branch-and-bound framework. We show
that the proposed method can provide the best statistical model based on AIC
for small-sized or medium-sized benchmark data sets in UCI Machine Learning
Repository. Furthermore, we show that this method finds good quality solutions
for large-sized benchmark data sets.


title:
Scalable Partial Least Squares Regression on Grammar-Compressed Data
  Matrices

abstract:
  With massive high-dimensional data now commonplace in research and industry,
there is a strong and growing demand for more scalable computational techniques
for data analysis and knowledge discovery. Key to turning these data into
knowledge is the ability to learn statistical models with high
interpretability. Current methods for learning statistical models either
produce models that are not interpretable or have prohibitive computational
costs when applied to massive data. In this paper we address this need by
presenting a scalable algorithm for partial least squares regression (PLS),
which we call compression-based PLS (cPLS), to learn predictive linear models
with a high interpretability from massive high-dimensional data. We propose a
novel grammar-compressed representation of data matrices that supports fast row
and column access while the data matrix is in a compressed form. The original
data matrix is grammar-compressed and then the linear model in PLS is learned
on the compressed data matrix, which results in a significant reduction in
working space, greatly improving scalability. We experimentally test cPLS on
its ability to learn linear models for classification, regression and feature
extraction with various massive high-dimensional data, and show that cPLS
performs superiorly in terms of prediction accuracy, computational efficiency,
and interpretability.


title: Zero-Shot Hashing via Transferring Supervised Knowledge

abstract:
  Hashing has shown its efficiency and effectiveness in facilitating
large-scale multimedia applications. Supervised knowledge e.g. semantic labels
or pair-wise relationship) associated to data is capable of significantly
improving the quality of hash codes and hash functions. However, confronted
with the rapid growth of newly-emerging concepts and multimedia data on the
Web, existing supervised hashing approaches may easily suffer from the scarcity
and validity of supervised information due to the expensive cost of manual
labelling. In this paper, we propose a novel hashing scheme, termed
\emph{zero-shot hashing} (ZSH), which compresses images of "unseen" categories
to binary codes with hash functions learned from limited training data of
"seen" categories. Specifically, we project independent data labels i.e.
0/1-form label vectors) into semantic embedding space, where semantic
relationships among all the labels can be precisely characterized and thus seen
supervised knowledge can be transferred to unseen classes. Moreover, in order
to cope with the semantic shift problem, we rotate the embedded space to more
suitably align the embedded semantics with the low-level visual feature space,
thereby alleviating the influence of semantic gap. In the meantime, to exert
positive effects on learning high-quality hash functions, we further propose to
preserve local structural property and discrete nature in binary codes.
Besides, we develop an efficient alternating algorithm to solve the ZSH model.
Extensive experiments conducted on various real-life datasets show the superior
zero-shot image retrieval performance of ZSH as compared to several
state-of-the-art hashing methods.


title:
A counterexample to the extension space conjecture for realizable
  oriented matroids

abstract:
  The extension space conjecture of oriented matroid theory states that the
space of all one-element, non-loop, non-coloop extensions of a realizable
oriented matroid of rank $d$ has the homotopy type of a sphere of dimension
$d-1$. We disprove this conjecture by showing the existence of a realizable
uniform oriented matroid of high rank and corank 3 with disconnected extension
space.


title: Search and Placement in Tiered Cache Networks

abstract:
  Content distribution networks have been extremely successful in today's
Internet. Despite their success, there are still a number of scalability and
performance challenges that motivate clean slate solutions for content
dissemination, such as content centric networking. In this paper, we address
two of the fundamental problems faced by any content dissemination system:
content search and content placement.
  We consider a multi-tiered, multi-domain hierarchical system wherein random
walks are used to cope with the tradeoff between exploitation of known paths
towards custodians versus opportunistic exploration of replicas in a given
neighborhood. TTL-like mechanisms, referred to as reinforced counters, are used
for content placement. We propose an analytical model to study the interplay
between search and placement. The model yields closed form expressions for
metrics of interest such as the average delay experienced by users and the load
placed on custodians. Then, leveraging the model solution we pose a joint
placement-search optimization problem. We show that previously proposed
strategies for optimal placement, such as the square-root allocation, follow as
special cases of ours, and that a bang-bang search policy is optimal if content
allocation is given.


title:
The Turbulent Boundary Layer on a Horizontally Moving, Partially
  Submerged, Surface-Piercing Vertical Wall

abstract:
  The complex interactions between turbulence and the free surface, including
air entrainment processes, in boundary layer shear flows created by vertical
surface-piercing plates are considered. A laboratory-scale device was built
that utilizes a surface-piercing stainless steel belt that travels in a loop
around two vertical rollers, with one length of the belt between the rollers
acting as a horizontally-moving flat wall. The belt is operated both as a
suddenly-started plate to reproduce boundary layer flow or at steady state in
the presence of a stationary flat plate positioned parallel to the belt to
create a Couette flow with a free surface. Surface profiles are measured with a
cinematic laser-induced fluorescence system in both experiments and air
entrainment events and bubble motions are observed with stereo underwater
white-light movies in the suddenly started belt experiment. It is found that
the RMS surface height fluctuations, $\eta$, peak near the boundaries of the
flows and increase approximately linearly with belt speed. In the Couette flow
experiments, a dominant peak in the spectrum of $\partial\eta/\partial t$ is
found at the dimensionless frequency $fH/U\approx 0.7$. In the suddenly started
belt experiment, surface fluctuations appear to be strongly influenced by
sub-surface turbulence within the boundary layer, while ripples propagate
freely when farther from the belt. Additionally, some mechanisms for air
entrainment are observed and comparisons are made to predictions of incipient
entrainment conditions in Brocchini and Pregrine (J. Fluid Mech., 499, 225-254,
2001).


title: Inscribed Matter Communication: Part II

abstract:
  This paper is Part II of a two-paper set which develops a finest-grain
per-molecule timing treatment of molecular communication. We first consider a
simple one-molecule timing channel with a molecule launch deadline, similar to
but different from previous work ("Bits Through Queues") where the constraint
was mean launch time. We also derive a number of results related to the {\em
ordering entropy}, a key quantity which undergirds the capacity bounds for the
molecular timing channel, both with and without token data payloads. We then
conclude with an upper bound on molecular timing-channel capacity.


title:
Highly efficient isolation of waterborne sound by an air-sealed
  metasurface

abstract:
  Underwater sound isolation has been a long-standing fundamental issue in
industry and military fields. Starting from a simple theoretical model, here an
air-sealed metasurface is proposed to overcome this problem. Comparing with the
sample without filling air, the effective impedance of the air-sealed one is
greatly reduced and strikingly mismatch with water, accompanying another merit
of low sound speed. Deeply suppressed sound transmission (~10-5) through such a
metasurface is observed experimentally over a wide range of ultrasonic
frequencies and incident angles.


title:
Zero kinematic viscosity-magnetic diffusion limit of the incompressible
  viscous magnetohydrodynamic equations with Navier boundary conditions

abstract:
  We investigate the zero kinematic viscosity-magnetic diffusion limit of the
incompressible viscous magnetohydrodynamic equations with Navier boundary
conditions in a smooth bounded domain $\Omega\subset\mathbb{R}^3$. We obtain
the uniform regularity of solutions with respect to the kinematic viscosity
coefficient and the magnetic diffusivity coefficient. These solutions are
uniformly bounded in a conormal Sobolev space and $W^{1,\infty}(\Omega)$ which
allow us to take the zero kinematic viscosity-magnetic diffusion limit.
Moreover, we also get the rates of convergence.


title:
A characterization of arithmetic functions satisfying
  $f(u^{2}+kv^{2})=f^{2}(u)+kf^{2}(v)$

abstract:
  In this paper, we mainly discuss the characterization of a class of
arithmetic functions $f: N \rightarrow C$ such that
$f(u^{2}+kv^2)=f^{2}(u)+kf^{2}(v)$ $(k, u, v \in N)$. We obtain a
characterization with given condition, propose a conjecture and show the result
holds for $k \in \{2, 3, 4, 5 \}$.


title: Exterior Navier-Stokes flows for bounded data

abstract:
  We prove unique existence of mild solutions on $L^{\infty}_{\sigma}$ for the
Navier-Stokes equations in an exterior domain in $ \mathbb{R}^{n}$, $n\geq 2$,
subject to the non-slip boundary condition.


title: Making sound vortices by metasurfaces

abstract:
  Based on the Huygens-Fresnel principle, a metasurface structure is designed
to generate a sound vortex beam in airborne environment. The metasurface is
constructed by a thin planar plate perforated with a circular array of deep
subwavelength resonators with desired phase and amplitude responses. The
metasurface approach in making sound vortices is validated well by full-wave
simulations and experimental measurements. Potential applications of such
artificial spiral beams can be anticipated, as exemplified experimentally by
the torque effect exerting on an absorbing disk.


title: Three-dimensional Critical Dirac semimetal in KMgBi

abstract:
  We predicted that AMgBi (A=K,Rb Cs), which have the same lattice structures
as the 111 family of iron-based superconductors (Na/LiFeAs), are
symmetry-protected Dirac semimetals located near the boundary of type-I and
type-II Dirac semimetal phases. Doping Rb or Cs into KMgBi can drive the
transition between the two phases. The materials can also be turned into Weyl
semimetals and topological insulators by explicitly or spontaneously breaking
time-reversal symmetry and C$_4$ lattice symmetry respectively.


title:
Performance Analysis of Target Parameters Estimation Using Multiple
  Widely Separated Antenna Arrays

abstract:
  Target parameter estimation performance is investigated for a radar employing
a set of widely separated transmitting and receiving antenna arrays. Cases with
multiple extended targets are considered under two signal model assumptions:
stochastic and deterministic. The general expressions for the corresponding
Cramer-Rao lower bound (CRLB) and the asymptotic properties of the
maximum-likelihood (ML) estimator are derived for a radar with $M_t$ arrays of
$L_t$ transmitting elements and $M_r$ arrays of $L_r$ receiving elements for
both types of signal models.
  It is shown that for an infinitely large product $M_tM_r$, and a finite
$L_r$, the ML estimator is consistent and efficient under the stochastic model,
while the deterministic model requires $M_tM_r$ to be finite and $L_r$ to be
infinitely large in order to guarantee consistency and efficiency.
  Monte Carlo simulations further investigate the estimation performance of the
proposed radar configuration in practical scenarios with finite $M_tM_r$ and
$L_r$, and a fixed total number of available receiving antenna elements, $M_r
L_r$. The numerical results demonstrate that grouping receiving elements into
properly sized arrays reduces the mean squared error (MSE) and decreases the
threshold SNR. In the numerical examples considered, the preferred
configurations employ $M_t M_r > 1$. In fact, when $M_t M_r$ becomes too small,
due to the loss of the geometric gain, the estimation performance becomes
strongly dependent on the particular scenario and can degrade significantly,
while the CRLB may become a poor prediction of the MSE even for high SNR. This
suggests it may be advantageous to employ approaches where neither $M_tM_r$ nor
$L_r$ are too small.


title:
Characterization of Parity-Time Symmetry in Photonic Lattices Using
  Heesh-Shubnikov Group Theory

abstract:
  We investigate the properties of parity-time symmetric periodic photonic
structures using Heesh-Shubnikov group theory. Classical group theory cannot be
used to categorize the symmetry of the eigenmodes because the time-inversion
operator is antiunitary. Fortunately, corepresentations of Heesh-Shubnikov
groups have been developed to characterize the effect of antiunitary operators
on eigenfunctions. Using the example structure of a one-dimensional photonic
lattice, we identify the corepresentations of eigenmodes at both low and high
symmetry points in the photonic band diagram. We find that thresholdless
parity-time transitions are associated with particular classes of
corepresentations. The approach is completely general and can be applied to
parity-time symmetric photonic lattices of any dimension. The predictive power
of this approach provides a powerful design tool for parity-time symmetric
photonic device design.


title: Some properties and applications of odd-colorable $r$-hypergraphs

abstract:
  Let $r\geq2$ and $r$ be even. An $r$-hypergraph $G$ on $n$ vertices is called
odd-colorable if there exists a map $\varphi:[n]\rightarrow\lbrack r]$ such
that for any edge $\{j_{1},j_{2},\cdots,j_{r}\}$ of $G$, we have
$\varphi(j_{1})+\varphi(j_{2})+\cdot\cdot\cdot+\varphi(j_{r})\equiv
r/2(\operatorname{mod}r).$ In this paper, we first determine that, if
$r=2^{q}(2t+1)$ and $n\ge 2^{q}(2^{q}-1)r$, then the maximum chromatic number
in the class of the odd-colorable $r$-hypergraphs on $n$ vertices is $2^q$,
which answers a question raised by V. Nikiforov recently in [V. Nikiforov,
Hypergraphs and hypermatrices with symmetric spectrum. Prinprint available in
arXiv:1605.00709v2, 10 May, 2016]. We also study some applications of the
symmetric spectral property of the odd-colorable $r$-graphs given in that same
paper by V. Nikiforov. We show that the Laplacian spectrum and the signless
Laplacian spectrum of an $r$-hypergraph $G$ are equal if and only if $G$ is
odd-colorable, and then study some further applications of these spectral
properties.


title: Monte Carlo Set-Membership Filtering for Nonlinear Dynamic Systems

abstract:
  When underlying probability density functions of nonlinear dynamic systems
are unknown, the filtering problem is known to be a challenging problem. This
paper attempts to make progress on this problem by proposing a new class of
filtering methods in bounded noise setting via set-membership theory and Monte
Carlo (boundary) sampling technique, called Monte Carlo set-membership filter.
The set-membership prediction and measurement update are derived by recent
convex optimization methods based on S-procedure and Schur complement. To
guarantee the on-line usage, the nonlinear dynamics are linearized about the
current estimate and the remainder terms are then bounded by an optimization
ellipsoid, which can be described as a semi-infinite optimization problem. In
general, it is an analytically intractable problem when dynamic systems are
nonlinear. However, for a typical nonlinear dynamic system in target tracking,
we can analytically derive some regular properties for the remainder. Moreover,
based on the remainder properties and the inverse function theorem, the
semi-infinite optimization problem can be efficiently solved by Monte Carlo
boundary sampling technique. Compared with the particle filter, numerical
examples show that when the probability density functions of noises are
unknown, the performance of the Monte Carlo set-membership filter is better
than that of the particle filter.


title: Towards Characterizing International Routing Detours

abstract:
  There are currently no requirements (technical or otherwise) that BGP paths
must be contained within national boundaries. Indeed, some paths experience
international detours, i.e., originate in one country, cross international
boundaries and return to the same country. In most cases these are sensible
traffic engineering or peering decisions at ISPs that serve multiple countries.
In some cases such detours may be suspicious. Characterizing international
detours is useful to a number of players: (a) network engineers trying to
diagnose persistent problems, (b) policy makers aiming at adhering to certain
national communication policies, (c) entrepreneurs looking for opportunities to
deploy new networks, or (d) privacy-conscious states trying to minimize the
amount of internal communication traversing different jurisdictions. In this
paper we characterize international detours in the Internet during the month of
January 2016. To detect detours we sample BGP RIBs every 8 hours from 461
RouteViews and RIPE RIS peers spanning 30 countries. Then geolocate visible
ASes by geolocating each BGP prefix announced by each AS, mapping its presence
at IXPs and geolocation infrastructure IPs. Finally, analyze each global BGP
RIB entry looking for detours. Our analysis shows more than 5K unique BGP
prefixes experienced a detour. A few ASes cause most detours and a small
fraction of prefixes were affected the most. We observe about 544K detours.
Detours either last for a few days or persist the entire month. Out of all the
detours, more than 90% were transient detours that lasted for 72 hours or less.
We also show different countries experience different characteristics of
detours.


title:
Incident-energy-dependent spectral weight of resonant inelastic x-ray
  scattering in doped cuprates

abstract:
  We theoretically investigate the incident-photon energy omega_i dependence of
resonant inelastic x-ray scattering (RIXS) tuned for the Cu L edge in cuprate
superconductors by using the exact diagonalization technique for a single-band
Hubbard model. Depending on the value of core-hole Coulomb interaction in the
intermediate state, RIXS for non-spin-flip channel shows either a
omega_i-dependent fluorescencelike or omega_i-independent Raman-like behavior
for hole doping. An analysis of x-ray absorption suggests that the core-hole
Coulomb interaction is larger than on-site Coulomb interaction in the Hubbard
model, resulting in a fluorescencelike behavior in RIXS consistent with recent
RIXS experiments. A shift on the high-energy side of the center of spectral
distribution is also predicted for electron-doped systems though spectral
weight is small. Main structures in spin-flip channel exhibit a Raman-like
behavior as expected, accompanied with a fluorescencelike behavior with small
intensity.


title: On spurious regressions with trending variables

abstract:
  This paper examines three types of spurious regressions where both the
dependent and independent variables contain deterministic trends, stochastic
trends, or breaking trends. We show that the problem of spurious regression
disappears if the trend functions are included as additional regressors. In the
presence of autocorrelation, we show that using a Feasible General Least Square
(FGLS) estimator can help alleviate or eliminate the problem. Our theoretical
results are clearly reflected in finite samples. As an illustration, we apply
our methods to revisit the seminal study of Yule (1926).


title: Proof Complexity Lower Bounds from Algebraic Circuit Complexity

abstract:
  We give upper and lower bounds on the power of subsystems of the Ideal Proof
System (IPS), the algebraic proof system recently proposed by Grochow and
Pitassi, where the circuits comprising the proof come from various restricted
algebraic circuit classes. This mimics an established research direction in the
boolean setting for subsystems of Extended Frege proofs, where proof-lines are
circuits from restricted boolean circuit classes. Except one, all of the
subsystems considered in this paper can simulate the well-studied
Nullstellensatz proof system, and prior to this work there were no known lower
bounds when measuring proof size by the algebraic complexity of the polynomials
(except with respect to degree, or to sparsity).
  We give two general methods of converting certain algebraic lower bounds into
proof complexity ones. Our methods require stronger notions of lower bounds,
which lower bound a polynomial as well as an entire family of polynomials it
defines. Our techniques are reminiscent of existing methods for converting
boolean circuit lower bounds into related proof complexity results, such as
feasible interpolation. We obtain the relevant types of lower bounds for a
variety of classes (sparse polynomials, depth-3 powering formulas, read-once
oblivious algebraic branching programs, and multilinear formulas), and infer
the relevant proof complexity results. We complement our lower bounds by giving
short refutations of the previously-studied subset-sum axiom using IPS
subsystems, allowing us to conclude strict separations between some of these
subsystems.


title:
The BINP HLS to measurement vertical changes on PAL-XFEL building and
  ground

abstract:
  PAL-XFEL, a 4th generation light source, is currently being installed and
will be completed by December of 2015 so that users can be supported beginning
in 2016. PAL-XFEL equipment should continuously maintain the bunch-to-bunch
beam parameter (60Hz, Energy 10GeV, Charge 200pC, Bunch Length 60fs, Emittance
X/Y 0.481mm/0.256mm rad) in order to supply the energy, flux and timing of
stable photons in tests by beam line users. To this end, PAL-XFEL equipment has
to be kept precisely aligned (Linear Accelerator +/- 100um, Undulator +/-
50um). As a part of the process for installing PAL-XFEL, a GPS-used surface
geodetic network is being constructed for precise equipment measurement and
alignment, and the installation of a tunnel measurement network inside
buildings is in preparation; additionally, the fiducialization of major
equipment is underway. After PAL-XFEL equipment is optimized and aligned, if
the ground and buildings go through vertical changes during operation,
misalignment (and tilt) of equipment including various magnets and RF
structures will cause errors in the electron beam trajectory, which will lead
to changes to the beam parameter. For continuous and systemic measurement of
vertical changes in buildings and to monitor ground sinking and uplifting, the
Budker Institute of Nuclear Physics (BINP) Ultrasonic-type Hydrostatic
Levelling System (HLS) is to be installed and operated in all sections of
PAL-XFEL for linear accelerator, insertion device (Undulator) and beam line.
This study will introduce the operation principle, design concept and
advantages (self-calibration) of HLS, and will outline its installation plan
and operation plan.


title:
SANTA: Self-Aligned Nanotrench Ablation via Joule Heating for Probing
  Sub-20 nm Devices

abstract:
  Manipulating materials at the nanometer scale is challenging, particularly if
alignment with nanoscale electrodes is desired. Here we describe a
lithography-free, self-aligned nanotrench ablation (SANTA) technique to create
nanoscale trenches in a polymer like poly(methyl) methacrylate (PMMA). The
nanotrenches are self-aligned with carbon nanotube (CNT) and graphene ribbon
electrodes through a simple Joule heating process. Using simulations and
experiments we investigate how the Joule power, ambient temperature, PMMA
thickness, and substrate properties can improve the spatial resolution of this
technique. We achieve sub-20 nm nanotrenches for the first time, by lowering
the ambient temperature and reducing the PMMA thickness. We also demonstrate a
functioning nanoscale resistive memory (RRAM) bit self-aligned with a CNT
control device, achieved through the SANTA approach. This technique provides an
elegant and inexpensive method to probe nanoscale devices using self-aligned
electrodes, without the use of conventional alignment or lithography steps.


title:
Collecting and Analyzing Data from Smart Device Users with Local
  Differential Privacy

abstract:
  Organizations with a large user base, such as Samsung and Google, can
potentially benefit from collecting and mining users' data. However, doing so
raises privacy concerns, and risks accidental privacy breaches with serious
consequences. Local differential privacy (LDP) techniques address this problem
by only collecting randomized answers from each user, with guarantees of
plausible deniability; meanwhile, the aggregator can still build accurate
models and predictors by analyzing large amounts of such randomized data. So
far, existing LDP solutions either have severely restricted functionality, or
focus mainly on theoretical aspects such as asymptotical bounds rather than
practical usability and performance. Motivated by this, we propose Harmony, a
practical, accurate and efficient system for collecting and analyzing data from
smart device users, while satisfying LDP. Harmony applies to multi-dimensional
data containing both numerical and categorical attributes, and supports both
basic statistics (e.g., mean and frequency estimates), and complex machine
learning tasks (e.g., linear regression, logistic regression and SVM
classification). Experiments using real data confirm Harmony's effectiveness.


title:
Boundary-induced spin density waves in linear Heisenberg
  antiferromagnetic spin chains with $\mathbf{S \ge 1}$

abstract:
  Linear Heisenberg antiferromagnets (HAFs) are chains of spin-$S$ sites with
isotropic exchange $J$ between neighbors. Open and periodic boundary conditions
return the same ground state energy in the thermodynamic limit, but not the
same spin $S_G$ when $S \ge 1$. The ground state of open chains of N spins has
$S_G = 0$ or $S$, respectively, for even or odd N. Density matrix
renormalization group (DMRG) calculations with different algorithms for even
and odd N are presented up to N = 500 for the energy and spin densities
$\rho(r,N)$ of edge states in HAFs with $S = 1$, 3/2 and 2. The edge states are
boundary-induced spin density waves (BI-SDWs) with $\rho(r,N)\propto(-1)^{r-1}$
for $r=1,2,\ldots N$. The SDWs are in phase when N is odd, out of phase when N
is even, and have finite excitation energy $\Gamma(N)$ that decreases
exponentially with N for integer $S$ and faster than 1/N for half integer $S$.
The spin densities and excitation energy are quantitatively modeled for integer
$S$ chains longer than $5 \xi$ spins by two parameters, the correlation length
$\xi$ and the SDW amplitude, with $\xi = 6.048$ for $S = 1$ and 49.0 for $S =
2$. The BI-SDWs of $S = 3/2$ chains are not localized and are qualitatively
different for even and odd N. Exchange between the ends for odd N is mediated
by a delocalized effective spin in the middle that increases $|\Gamma(N)|$ and
weakens the size dependence. The nonlinear sigma model (NL$\sigma$M) has been
applied the HAFs, primarily to $S = 1$ with even N, to discuss spin densities
and exchange between localized states at the ends as $\Gamma(N) \propto (-1)^N
\exp(-N/\xi)$...


title:
Observation of an Alfv\'en Wave Parametric Instability in a Laboratory
  Plasma

abstract:
  A shear Alfv\'en wave parametric instability is observed for the first time
in the laboratory. When a single finite $\omega/\Omega_i$ kinetic Alfv\'en wave
(KAW) is launched in the Large Plasma Device above a threshold amplitude, three
daughter modes are produced. These daughter modes have frequencies and parallel
wave numbers that are consistent with copropagating KAW sidebands and a low
frequency nonresonant mode. The observed process is parametric in nature, with
the frequency of the daughter modes varying as a function of pump wave
amplitude. The daughter modes are spatially localized on a gradient of the pump
wave magnetic field amplitude in the plane perpendicular to the background
field, suggesting that perpendicular nonlinear forces (and therefore
$k_{\perp}$ of the pump wave) play an important role in the instability
process. Despite this, modulational instability theory with $k_{\perp}=0$ has
several features in common with the observed nonresonant mode and Alfv\'en wave
sidebands.


title:
Flare Generated Shock Wave Propagation Through Solar Coronal Arcade
  Loops and Associated Type II Radio Burst

abstract:
  This paper presents multiwavelength observations of a flare-generated type II
radio burst. The kinematics of the shock derived from the type II closely match
a fast EUV wave seen propagating through coronal arcade loops. The EUV wave was
closely associated with an impulsive M1.0 flare without a related coronal mass
ejection, and was triggered at one of the footpoints of the arcade loops in
active region NOAA 12035. It was initially observed in the AIA 335 \AA\ images
with a speed of ~800 km/s and accelerated to ~1490 km/s after passing through
the arcade loops. A fan-spine magnetic topology was revealed at the flare site.
A small, confined filament eruption (~340 km/s) was also observed moving in the
opposite direction to the EUV wave. We suggest that breakout reconnection in
the fan-spine topology triggered the flare and associated EUV wave that
propagated as a fast shock through the arcade loops.


title:
Accumulate then Forward: An Opportunistic Relaying Protocol for
  Wireless-Powered Cooperative Communications

abstract:
  This paper investigates a wireless-powered cooperative communication network
consisting of a source, a destination and a multi-antenna decode-and-forward
relay. We consider the relay as a wireless-powered node that has no external
power supply; but it is equipped with an energy harvesting (EH) unit and a
rechargeable battery such that it can harvest and accumulate energy from
radio-frequency signals broadcast by the source. By fully incorporating the EH
feature of the relay, we develop an opportunistic relaying protocol, termed
accumulate-then-forward (ATF), for the considered WPCCN. We then adopt the
discrete Markov chain to model the dynamic charging and discharging behaviors
of the relay battery. Based on this, we derive a closed-form expression for the
exact outage probability of the proposed ATF protocol. Numerical results show
that the ATF scheme can outperform the direct transmission one, especially when
the amount of energy consumed by relay for information forwarding is optimized.


title: Contravariance through enrichment

abstract:
  We define strict and weak duality involutions on 2-categories, and prove a
coherence theorem that every bicategory with a weak duality involution is
biequivalent to a 2-category with a strict duality involution. For this purpose
we introduce "2-categories with contravariance", a sort of enhanced 2-category
with a basic notion of "contravariant morphism", which can be regarded either
as generalized multicategories or as enriched categories. This enables a
universal characterization of duality involutions using absolute weighted
colimits, leading to a conceptual proof of the coherence theorem.


title: Reduced fusion systems over 2-groups of small order

abstract:
  We prove, when $S$ is a $2$-group of order at most $2^9$, that each reduced
fusion system over $S$ is the fusion system of a finite simple group and is
tame. It then follows that each saturated fusion system over a $2$-group of
order at most $2^9$ is realizable. What is most interesting about this result
is the method of proof: we show that among $2$-groups with order in this range,
the ones which can be Sylow $2$-subgroups of finite simple groups are almost
completely determined by criteria based on Bender's classification of groups
with strongly $2$-embedded subgroups.


title: Pruning Random Forests for Prediction on a Budget

abstract:
  We propose to prune a random forest (RF) for resource-constrained prediction.
We first construct a RF and then prune it to optimize expected feature cost &
accuracy. We pose pruning RFs as a novel 0-1 integer program with linear
constraints that encourages feature re-use. We establish total unimodularity of
the constraint set to prove that the corresponding LP relaxation solves the
original integer program. We then exploit connections to combinatorial
optimization and develop an efficient primal-dual algorithm, scalable to large
datasets. In contrast to our bottom-up approach, which benefits from good RF
initialization, conventional methods are top-down acquiring features based on
their utility value and is generally intractable, requiring heuristics.
Empirically, our pruning algorithm outperforms existing state-of-the-art
resource-constrained algorithms.


title: Perfect Embezzlement of Entanglement

abstract:
  Van Dam and Hayden introduced a concept commonly referred to as embezzlement,
where, for any entangled quantum state $\phi$, there is an entangled catalyst
state $\psi$, from which a high fidelity approximation of $\phi \otimes \psi$
can be produced using only local operations. We investigate a version of this
where the embezzlement is perfect (i.e., the fidelity is 1). We prove that
perfect embezzlement is impossible in a tensor product framework, even with
infinite-dimensional Hilbert spaces and infinite entanglement entropy. Then we
prove that perfect embezzlement is possible in a commuting operator framework.
We prove this using the theory of C*-algebras and we also provide an explicit
construction. Next, we apply our results to analyze perfect versions of a
nonlocal game introduced by Regev and Vidick. Finally, we analyze the structure
of perfect embezzlement protocols in the commuting operator model, showing that
they require infinite-dimensional Hilbert spaces.


title: Convex lattice polygonal lines with a constrained number of vertices

abstract:
  A detailed combinatorial analysis of planar convex lattice polygonal lines is
presented. This makes it possible to answer an open question of Vershik
regarding the existence of a limit shape when the number of vertices is
constrained.


title:
Systems of sets of lengths: Transfer Krull monoids versus weakly Krull
  monoids

abstract:
  Transfer Krull monoids are monoids which allow a weak transfer homomorphism
to a commutative Krull monoid, and hence the system of sets of lengths of a
transfer Krull monoid coincides with that of the associated commutative Krull
monoid. We unveil a couple of new features of the system of sets of lengths of
transfer Krull monoids over finite abelian groups G, and we provide a complete
description of the system for all groups G having Davenport constant D(G) = 5
(these are the smallest groups for which no such descriptions were known so
far). Under reasonable algebraic finiteness assumptions, sets of lengths of
transfer Krull monoids and of weakly Krull monoids satisfy the Structure
Theorem for Sets of Lengths. In spite of this common feature we demonstrate
that systems of sets of lengths for a variety of classes of weakly Krull
monoids are different from the system of sets of lengths of any transfer Krull
monoid.


title: Ricci iteration on homogeneous spaces

abstract:
  The Ricci iteration is a discrete analogue of the Ricci flow. We give the
first study of the Ricci iteration on a class of Riemannian manifolds that are
not K\"ahler. The Ricci iteration in the non-K\"ahler setting exhibits new
phenomena. Among them is the existence of so-called ancient Ricci iterations.
As we show, these are closely related to ancient Ricci flows and provide the
first nontrivial examples of Riemannian metrics to which the Ricci operator can
be applied infinitely many times. In some of the cases we study, these ancient
Ricci iterations emerge (in the Gromov--Hausdorff topology) from a collapsed
Einstein metric and converge smoothly to a second Einstein metric. In the case
of compact homogeneous spaces with maximal isotropy, we prove a relative
compactness result that excludes collapsing.


title: HEMI: Hyperedge Majority Influence Maximization

abstract:
  In this work, we consider the problem of influence maximization on a
hypergraph. We first extend the Independent Cascade (IC) model to hypergraphs,
and prove that the traditional influence maximization problem remains
submodular. We then present a variant of the influence maximization problem
(HEMI) where one seeks to maximize the number of hyperedges, a majority of
whose nodes are influenced. We prove that HEMI is non-submodular under the
diffusion model proposed.


title: Statistical Mechanics of Avalanches

abstract:
  Statistical mechanics of infinite avalanches is studied in the framework of
nonequilibrium random-field Ising model. Critical behavior of the model on a
random graph (dilute Bethe lattice) is analyzed in detail. We show that sites
with a minimum coordination number 4 play a key role in the occurrence of
infinite avalanches. Earlier results which did not seem to fit together very
well are explained.


title:
Mortality and life expectancy forecasting for a group of populations in
  developed countries: A multilevel functional data method

abstract:
  A multilevel functional data method is adapted for forecasting age-specific
mortality for two or more populations in developed countries with high-quality
vital registration systems. It uses multilevel functional principal component
analysis of aggregate and population-specific data to extract the common trend
and population-specific residual trend among populations. If the forecasts of
population-specific residual trends do not show a long-term trend, then
convergence in forecasts may be achieved. This method is first applied to age-
and sex-specific data for the United Kingdom, and its forecast accuracy is then
further compared with several existing methods, including independent
functional data and product-ratio methods, through a multi-country comparison.
The proposed method is also demonstrated by age-, sex- and state-specific data
in Australia, where the convergence in forecasts can possibly be achieved by
sex and state. For forecasting age-specific mortality, the multilevel
functional data method is more accurate than the other coherent methods
considered. For forecasting female life expectancy at birth, the multilevel
functional data method is outperformed by the Bayesian method of \cite{RLG14}.
For forecasting male life expectancy at birth, the multilevel functional data
method performs better than the Bayesian methods in terms of point forecasts,
but less well in terms of interval forecasts. Supplementary materials for this
article are available online.


title: Holographic Construction of Quantum Field Theory using Wavelets

abstract:
  Wavelets encode data at multiple resolutions, which in a wavelet description
of a quantum field theory, allows for fields to carry, in addition to
space-time coordinates, an extra dimension: scale. A recently introduced Exact
Holographic Mapping [C.H. Lee and X.-L. Qi, Phys. Rev. B 93, 035112 (2016)]
uses the Haar wavelet basis to represent the free Dirac fermionic quantum field
theory (QFT) at multiple renormalization scales thereby inducing an emergent
bulk geometry in one higher dimension. This construction is, in fact, generic
and we show how higher families of Daubechies wavelet transforms of 1+1
dimensional scalar bosonic QFT generate a bulk description with a variable rate
of renormalization flow. In the massless case, where the boundary is described
by conformal field theory, the bulk correlations decay with distance consistent
with an Anti-de-Sitter space (AdS3) metric whose radius of curvature depends on
the wavelet family used. We propose an experimental demonstration of the
bulk/boundary correspondence via a digital quantum simulation using Gaussian
operations on a set of quantum harmonic oscillator modes.


title:
Misunderstanding that the Effective Action is Convex under Broken
  Symmetry

abstract:
  The widespread belief that the effective action is convex and has a flat
bottom under broken global symmetry is shown to be wrong. We show spontaneous
symmetry breaking necessarily accompanies non-convexity in the effective action
for quantum field theory, or in the free energy for statistical mechanics, and
clarify the magnitude of non-convexity. For quantum field theory, it is also
proved that translational invariance breaks spontaneously when the system is in
the non-convex region, and that different vacua of spontaneously broken
symmetry cannot be superposed.
  As applications of non-convexity, we study the first-order phase transition
which happens at the zero field limit of spontaneously broken symmetry, and we
propose a simple model of phase coexistence which obeys the Born rule.


title:
Localized Reduced Basis Approximation of a Nonlinear Finite Volume
  Battery Model with Resolved Electrode Geometry

abstract:
  In this contribution we present first results towards localized model order
reduction for spatially resolved, three-dimensional lithium-ionbattery models.
We introduce a localized reduced basis scheme based on non-conforming local
approximation spaces stemming from a finite volume discretizationof the
analytical model and localized empirical operator interpolation for the
approximation of the model's nonlinearities. Numerical examples are provided
indicating the feasibility of our approach.


title:
Raman signatures of inversion symmetry breaking and structural phase
  transition in type-II Weyl semimetal MoTe2

abstract:
  Transition metal dichalcogenide MoTe$_2$ is an important candidate for
realizing the newly predicted type-IIWeyl fermions, for which the breaking of
the inversion symmetry is a prerequisite. Here we present direct spectroscopic
evidence for the inversion symmetry breaking in the low temperature phase of
MoTe$_2$ by systematic Raman experiments and first principles calculations. We
identify five lattice vibrational modes which are Raman active only in
noncentrosymmetric structure at low temperature. A hysteresis is also observed
in the peak intensity of inversion symmetry activated Raman modes, confirming a
temperature induced structural phase transition with a concomitant change in
the inversion symmetry. Our results provide definitive evidence for the low
temperature noncentrosymmetric T$_d$ phase from vibrational spectroscopy, and
suggest MoTe$_2$ as an ideal candidate for investigating the temperature
induced topological phase transition.


title:
Nonlinear optical conductivity of a generic two band systems, with
  application to doped and gapped graphene

abstract:
  We present a general formulation to calculate the dynamic optical
conductivity, beyond the linear response regime, of any electronic system whose
quasiparticle dispersion is described by a two band model. Our phenomenological
model is based on the optical Bloch equations. In the steady state regime it
yields an analytic solution for the population inversion and the interband
coherence, which are nonlinear in the optical field intensity, including finite
doping and temperature effects. We explicitly show that the optical
nonlinearities are controlled by a single dimensionless parameter which is
directly proportional to the incident field strength and inversely proportional
to the optical frequency. This identification leads to a unified way to study
the dynamical conductivity and the differential transmission spectrum across a
wide range of optical frequencies, and optical field strength. We use our
formalism to analytically calculate the nonlinear optical conductivity of doped
and gapped graphene, deriving the well known universal ac conductivity of
$\sigma_0={e^2}/4\hbar$ in the linear response regime of low optical
intensities (or equivalently high frequencies) and non-linear deviations from
it which appear at high laser intensities (or low frequencies) including the
impact of finite doping and band-gap opening.


title:
An equation for the quench propagation velocity valid for high field
  magnet use of REBCO coated conductors

abstract:
  Based on a study of the thermophysical properties, we derived a practical
formula for the normal zone propagation velocity appropriate for
REBa$_2$Cu$_3$O$_{7-x}$ coated conductors in high magnetic fields. An
analytical expression to evaluate the current sharing temperature as a function
of the operating conditions is also proposed. The presented study has allowed
us to account for experimental results not fully understood in the framework of
the models widely used in the literature. In particular, we provided a
fundamental understanding of the experimental evidence that the normal zone
propagation velocity in REBa$_2$Cu$_3$O$_{7-x}$ coated conductors can be mainly
determined by the operating current, regardless of the applied field and
temperature.


title:
Non-equilibrium quantum transport coefficients and the transient
  dynamics of full counting statistics in the strong coupling and non-Markovian
  regimes

abstract:
  Non-equilibrium transport properties of quantum systems have recently become
experimentally accessible in a number of platforms in so-called full-counting
experiments that measure transient and steady state non-equilibrium transport
dynamics. We show that the effect of the measurement back-action can be
exploited to gain access to relevant transport coefficients. This relationship
is general, but becomes most conspicuous in the transient dynamics of open
quantum systems understrong coupling to non-Markovian environments. In order to
explore this regime, a new simulation method for the generation of full
counting statistics of non-Markovian, strong-coupling transport settings has
been developed that is expressed in terms of a hierarchy of equations of
motion. With this tool we gain access to the relevant regime and instantiate
our proposal with the study of energetic conductance between two baths
connected via a few level system.


title:
Spectral stability of periodic waves in the generalized reduced
  Ostrovsky equation

abstract:
  We consider stability of periodic travelling waves in the generalized reduced
Ostrovsky equation with respect to co-periodic perturbations. Compared to the
recent literature, we give a simple argument that proves spectral stability of
all smooth periodic travelling waves independently on the nonlinearity power.
The argument is based on the energy convexity and does not use coordinate
transformations of the reduced Ostrovsky equations to the semi-linear equations
of the Klein--Gordon type.


title:
Tricritical behaviour of the frustrated Ising antiferromagnet on the
  honeycomb lattice

abstract:
  We use the effective-field theory with correlations based on different
cluster sizes to investigate phase diagrams of the frustrated Ising
antiferromagnet on the honeycomb lattice with isotropic interactions of the
strength $J_1 < 0$ between nearest-neighbour pairs and $J_2 < 0$ between
next-nearest neighbour pairs of spins. We present results for the ground-state
energy as a function of the frustration parameter $R = J_2 /|J_1|$. We find
that the cluster-size has a considerable effect on the existence and location
of a tricritical point in the phase diagram at which the phase transition
changes from the second order to the first one.


title: On the Group of Almost-Riordan Arrays

abstract:
  We study a super group of the group of Riordan arrays, where the elements of
the group are given by a triple of power series. We show that certain subsets
are subgroups, and we identify a normal subgroup whose cosets correspond to
Riordan arrays. We give an example of an almost-Riordan array that has been
studied in the context of Hankel and Hankel plus Toepliz matrices, and we show
that suitably chosen almost-Riordan arrays can lead to transformations that
have interesting Hankel transform properties.


title: Solution of the Kirchhoff-Plateau problem

abstract:
  The Kirchhoff-Plateau problem concerns the equilibrium shapes of a system in
which a flexible filament in the form of a closed loop is spanned by a liquid
film, with the filament being modeled as a Kirchhoff rod and the action of the
spanning surface being solely due to surface tension. We establish the
existence of an equilibrium shape that minimizes the total energy of the system
under the physical constraint of non-interpenetration of matter, but allowing
for points on the surface of the bounding loop to come into contact. In our
treatment, the bounding loop retains a finite cross-sectional thickness and a
nonvanishing volume, while the liquid film is represented by a set with finite
two-dimensional Hausdorff measure. Moreover, the region where the liquid film
touches the surface of the bounding loop is not prescribed a priori. Our
mathematical results substantiate the physical relevance of the chosen model.
Indeed, no matter how strong is the competition between surface tension and the
elastic response of the filament, the system is always able to adjust to
achieve a configuration that complies with the physical constraints encountered
in experiments.


title: Optimal Liquidation under Partial Information with Price Impact

abstract:
  We study the optimal liquidation problem in a market model where the bid
price follows a geometric pure jump process whose local characteristics are
driven by an unobservable finite-state Markov chain and by the liquidation
rate. This model is consistent with stylized facts of high frequency data such
as the discrete nature of tick data and the clustering in the order flow. We
include both temporary and permanent effects into our analysis. We use
stochastic filtering to reduce the optimal liquidation problem to an equivalent
optimization problem under complete information. This leads to a stochastic
control problem for piecewise deterministic Markov processes (PDMPs). We carry
out a detailed mathematical analysis of this problem. In particular, we derive
the optimality equation for the value function, we characterize the value
function as continuous viscosity solution of the associated dynamic programming
equation, and we prove a novel comparison result. The paper concludes with
numerical results illustrating the impact of partial information and price
impact on the value function and on the optimal liquidation rate.


title: Design of the readout electronics for the DAMPE Silicon Tracker detector

abstract:
  The Silicon Tracker (STK) is a detector of the DAMPE satellite to measure the
incidence direction of high energy cosmic ray. It consists of 6 X-Y double
layers of silicon micro-strip detectors with 73,728 readout channels. It's a
great challenge to readout the channels and process the huge volume of data in
the critical space environment. 1152 Application Specific Integrated Circuits
(ASIC) and 384 ADCs are adopted to readout the detector channels. The 192
Tracker Front-end Hybrid (TFH) modules and 8 identical Tracker Readout Board
(TRB) modules are designed to control and digitalize the front signals. In this
paper, the design of the readout electronics for STK and its performance will
be presented in detail.


title:
Note on the classification of super-resolution in far-field microscopy
  and information theory

abstract:
  In recent years several far-field microscopy techniques have been developed
which manage to overcome the diffraction limit of resolution. A unifying
classification scheme for them is clearly desirable. We argue that existing
schemes based on the information capacity of the optical system can not easily
be extended to cover e.g., STED microscopy or techniques based on single
molecule imaging. We suggest a classification based on a reconstruction of the
Abbe limit.


title: Lift force due to odd (Hall) viscosity

abstract:
  We study the problem of flow of a neutral gas past an infinite cylinder at
right angle to its axis at low Reynolds number when the fluid is characterized
by broken time-reversal invariance, and hence by odd viscosity in addition to
the normal even one. We solve the Oseen approximation to Navier-Stokes equation
and calculate the lift force which appears due to the odd viscosity.


title:
Determination of Low Loss in Isotopically Pure Single Crystal $^{28}$Si
  at Low Temperatures and Single Microwave Photon Energy

abstract:
  The low dielectric losses of an isotropically pure single crystal $^{28}$Si
sample were determined at a temperature of 20 mK and at powers equivalent to
that of a single photon. Whispering Gallery Mode (WGM) analysis revealed large
Quality Factors of order $2\times10^6$ (dielectric loss $\sim 5\times10^{-7}$)
at high powers, degrading to $7\times10^5$ (dielectric loss $\sim
1.4\times10^{-6}$) at single photon energy. A very low-loss narrow line width
paramagnetic spin flip transition was detected with extreme sensitivity in
$^{28}$Si, with very small concentration below $10^{11}$~cm$^{-3}$ (less than
10 parts per trillion) and g-factor of $1.995\pm0.008$. Such determination was
only possible due to the low dielectric photonic losses combined with the long
lifetime of the spin transition (low magnetic loss), which enhances the
magnetic AC susceptibility. Such low photonic loss at single photon energy
combined with the narrow line width of the spin ensemble, indicate that single
crystal $^{28}$Si could be an important crystal for future cavity QED
experiments.


title:
Boltzmann approach to high-order transport: the non-linear and non-local
  responses

abstract:
  The phenomenological textbook equations for the charge and heat transport are
extensively used in a number of fields ranging from semiconductor devices to
thermoelectricity. We provide a rigorous derivation of transport equations by
solving the Boltzmann equation in the relaxation time approximation and show
that the currents can be rigorously represented by an expansion in terms of the
'driving forces'. Besides the linear and non-linear response to the electric
field, the gradient of the chemical potential and temperature, there are also
terms that give the response to the higher-order derivatives of the potentials.
These new, non-local responses, which have not been discussed before, might
play an important role for some materials and/or in certain conditions, like
extreme miniaturization. Our solution provides the general solution of the
Boltzmann equation in the relaxation time approximation (or equivalently the
particular solution for the specific boundary conditions). It differs from the
Hilbert expansion which provides only one of infinitely many solutions which
may or may not satisfy the required boundary conditions.


title:
A priori error estimates and computational studies for a Fermi
  pencil-beam equation

abstract:
  We derive a priori error estimates for the standard Galerkin and streamline
diffusion finite element methods for the Fermi pencil-beam equation obtained
from a fully three dimensional Fokker-Planck equation in space ${\mathbf
x}=(x,y,z)$ and velocity $\tilde {\mathbf v}=(\mu, \eta, \xi)$ variables. The
Fokker-Planck term appears as a Laplace-Beltrami operator in the unit sphere.
The diffusion term in the Fermi equation is obtained as a projection of the FP
operator onto the tangent plane to the unit sphere at the pole $(1,0,0)$ and in
the direction of $ {\mathbf v}_0=(1,\eta, \xi)$. Hence the Fermi equation,
stated in three dimensional spatial domain ${\mathbf x}=(x,y,z)$, depends only
on two velocity variables ${\mathbf v}=(\eta, \xi)$. Since, for a certain
number of cross-sections, there is a closed form analytic solution available
for the Fermi equation, hence an a posteriori error estimate procedure is
unnecessary and in our adaptive algorithm for local mesh refinements we employ
the a priori approach. Different numerical examples, in two space dimensions
are justifying the theoretical results. Implementations show significant
reduction of the computational error by using our adaptive algorithm.


title: Process-theoretic characterisation of the Hermitian adjoint

abstract:
  We show that the physical principle "the adjoint associates to each state a
`test' for that state" fully characterises the Hermitian adjoint for pure
quantum theory, therefore providing the adjoint with operational meaning beyond
its standard mathematical definition. Also, we show that for general process
theories, which all admit a diagrammatic representation, this physical
principle induces a reflection operation.


title: Neutrino-Pair Exchange Long-Range Force Between Aggregate Matter

abstract:
  We study the long-range force arising between two neutral---of electric
charge---aggregates of matter due to a neutrino-pair exchange, in the limit of
zero neutrino mass. The conceptual basis for the construction of the effective
potential comes from the coherent scattering amplitude at low values of t. This
amplitude is obtained using the methodology of an unsubtracted dispersion
relation in t at threshold for s, where (s, t) are the Lorentz invariant
scattering variables. The ultraviolet behavior is irrelevant for the long-range
force. In turn, the absorptive part in the t-dependence is given by the
corresponding unitarity relation. We show that the potential describing this
force decreases as $r^{-5}$ at large separation distance r. This interaction is
described in terms of its own charge, which we call the weak flavor charge of
the interacting systems, that depends on the flavor of the neutrino as $Q_W^e =
2Z-N$, $Q_W^\mu = Q_W^\tau = -N$. The flavor dependence of the potential
factorizes in the product of the weak charges of the interacting systems, so
that the resulting force is always repulsive. Furthermore, this charge is
proportional to the number of constituent particles, which differs from the
global mass, so this interaction could be disentangled from gravitation through
deviations from the Equivalence Principle.


title: Electrically tunable multi-terminal SQUID-on-tip

abstract:
  We present a new nanoscale superconducting quantum interference device
(SQUID) whose interference pattern can be shifted electrically in-situ. The
device consists of a nanoscale four-terminal/four-junction SQUID fabricated at
the apex of a sharp pipette using a self-aligned three-step deposition of Pb.
In contrast to conventional two-terminal/two-junction SQUIDs that display
optimal sensitivity when flux biased to about a quarter of the flux quantum,
the additional terminals and junctions allow optimal sensitivity at arbitrary
applied flux, thus eliminating the magnetic field "blind spots". We demonstrate
spin sensitivity of 5 to 8 $\mu_B/\text{Hz}^{1/2}$ over a continuous field
range of 0 to 0.5 T, with promising applications for nanoscale scanning
magnetic imaging.


title:
Ultra-high Sensitivity Moment Magnetometry of Geological Samples Using
  Magnetic Microscopy

abstract:
  Paleomagnetically useful information is expected to be recorded by samples
with moments up to three orders of magnitude below the detection limit of
standard superconducting rock magnetometers. Such samples are now detectable
using recently developed magnetic microscopes, which map the magnetic fields
above room-temperature samples with unprecedented spatial resolutions and field
sensitivities. However, realizing this potential requires the development of
techniques for retrieving sample moments from magnetic microscopy data. With
this goal, we developed a technique for uniquely obtaining the net magnetic
moment of geological samples from magnetic microscopy maps of unresolved or
nearly unresolved magnetization. This technique is particularly powerful for
analyzing small, weakly magnetized samples such as meteoritic chondrules and
terrestrial silicate crystals like zircons. We validated this technique by
applying it to field maps generated from synthetic sources and also to field
maps measured using a superconducting quantum interference device (SQUID)
microscope above geological samples with moments down to 10^-15 Am2. For the
most magnetic rock samples, the net moments estimated from the SQUID microscope
data are within error of independent moment measurements acquired using lower
sensitivity standard rock magnetometers. In addition to its superior moment
sensitivity, SQUID microscope net moment magnetometry also enables the
identification and isolation of magnetic contamination and background sources,
which is critical for improving accuracy in paleomagnetic studies of weakly
magnetic rocks.


title:
Mid-Infrared intersubband polaritons in dispersive metal-insulator-metal
  resonators

abstract:
  We demonstrate room-temperature strong-coupling between a mid-infrared
($\lambda$=9.9 $\mu$m) intersubband transition and the fundamental cavity mode
of a metal-insulator-metal resonator. Patterning of the resonator surface
enables surface-coupling of the radiation and introduces an energy dispersion
which can be probed with angle-resolved reflectivity. In particular, the
polaritonic dispersion presents an accessible energy minimum at k=0 where -
potentially - polaritons can accumulate. We also show that it is possible to
maximize the coupling of photons into the polaritonic states and -
simultaneously - to engineer the position of the minimum Rabi splitting at a
desired value of the in-plane wavevector. This can be precisely accomplished
via a simple post-processing technique. The results are confirmed using the
temporal coupled mode theory formalism and their significance in the context of
the concept of strong critical coupling is highlighted.


title:
Curvature and geodesic instabilities in a geometrical approach to the
  planar three-body problem

abstract:
  The Maupertuis principle allows us to regard classical trajectories as
reparametrized geodesics of the Jacobi-Maupertuis (JM) metric on configuration
space. We study this geodesic reformulation of the planar three-body problem
with both Newtonian and attractive inverse-square potentials. The associated JM
metrics possess translation and rotation isometries in addition to scaling
isometries for the inverse-square potential with zero energy E. The geodesic
flow on the full configuration space $C^3$ (with collision points excluded)
leads to corresponding flows on its Riemannian quotients: the center of mass
configuration space $C^2$ and shape space $R^3$ (as well as $S^3$ and the shape
sphere $S^2$ for the inverse-square potential when E = 0). The corresponding
Riemannian submersions are described explicitly in `Hopf' coordinates which are
particularly adapted to the isometries. For equal masses subject to
inverse-square potentials, Montgomery shows that the zero-energy `pair of
pants' JM metric on the shape sphere is geodesically complete and has negative
gaussian curvature except at Lagrange points. We extend this to a proof of
boundedness and strict negativity of scalar curvatures everywhere on $C^2, R^3$
& $S^3$ with collision points removed. Sectional curvatures are also found to
be largely negative, indicating widespread geodesic instabilities. We obtain
asymptotic metrics near collisions, show that scalar curvatures have finite
limits and observe that the geodesic reformulation `regularizes' pairwise and
triple collisions on $C^2$ and its quotients for arbitrary masses and allowed
energies. For the Newtonian potential with equal masses and E=0, we find that
the scalar curvature on $C^2$ is strictly negative though it could have either
sign on $R^3$. However, unlike for the inverse-square potential, geodesics can
encounter curvature singularities at collisions in finite geodesic time.


title:
Adaptable Symbol Table Management by Meta Modeling and Generation of
  Symbol Table Infrastructures

abstract:
  Many textual software languages share common concepts such as defining and
referencing elements, hierarchical structures constraining the visibility of
names, and allowing for identical names for different element kinds. Symbol
tables are useful to handle those reference and visibility concepts. However,
developing a symbol table can be a tedious task that leads to an additional
effort for the language engineer. This paper presents a symbol table meta model
usable to define languagespecific symbol tables. Furthermore, we integrate this
symbol table meta model with a meta model of a grammar-based language
definition. This enables the language engineer to switch between the model
structure and the symbol table as needed. Finally, based on a grammarannotation
mechanism, our approach is able to generate a symbol table infrastructure that
can be used as is or serve as a basis for custom symbol tables.


title:
Solving reaction-diffusion equations on evolving surfaces defined by
  biological image data

abstract:
  We present a computational approach for solving reaction-diffusion equations
on evolving surfaces which have been obtained from cell image data. It is based
on finite element spaces defined on surface triangulations extracted from time
series of 3D images. A model for the transport of material between the
subsequent surfaces is required where we postulate a velocity in normal
direction. We apply the technique to image data obtained from a spreading
neutrophil cell. By simulating FRAP experiments we investigate the impact of
the evolving geometry on the recovery. We find that for idealised FRAP
conditions, changes in membrane geometry, easily account for differences of
$\times 10$ in recovery half-times, which shows that experimentalists must take
great care when interpreting membrane photobleaching results. We also
numerically solve an activator -- depleted substrate system and report on the
effect of the membrane movement on the pattern evolution.


title:
A 0.3-2.6 TOPS/W Precision-Scalable Processor for Real-Time Large-Scale
  ConvNets

abstract:
  A low-power precision-scalable processor for ConvNets or convolutional neural
networks (CNN) is implemented in a 40nm technology. Its 256 parallel processing
units achieve a peak 102GOPS running at 204MHz. To minimize energy consumption
while maintaining throughput, this works is the first to both exploit the
sparsity of convolutions and to implement dynamic precision-scalability
enabling supply- and energy scaling. The processor is fully C-programmable,
consumes 25-288mW at 204 MHz and scales efficiency from 0.3-2.6 real TOPS/W.
This system hereby outperforms the state-of-the-art up to 3.9x in energy
efficiency.


title: On the octonionic Bergman kernel

abstract:
  By introducing a suitable new definition for the inner product on the
octonionic Bergman space, we determine the explicit form of the octonionic
Bergman kernel, in the framework of octonionic analysis which is
non-commutative and non-associative.


title:
Atomic configuration and properties of austenitic steels at finite
  temperature: The effect of longitudinal spin fluctuations

abstract:
  High temperature atomic configurations of fcc Fe-Cr-Ni alloys with alloy
composition close to austenitic steel are studied in statistical thermodynamic
simulations with effective interactions obtained in ab initio calculations. The
latter are done taking longitudinal spin fluctuations (LSF) into consideration
within a quasiclassical phenomenological model. It is demonstrated that
magnetic state affects greatly the alloy properties and in particular, it is
shown that the LSF substantially modify the bonding and interatomic
interactions of fcc Fe-Cr-Ni alloys even at ambient conditions. The calculated
atomic short-range order (SRO) is in reasonable agreement with existing
experimental data for Fe0.56}Cr0.21Ni0.23, which has strong preference for the
(001) type ordering between Ni and Cr atoms. A similar ordering tendency is
found for the Fe0.75Cr0.17Ni0.08 alloy composition, which approximately
corresponds to the widely used 304 and 316 austenitic steel grades.


title: The Bivariate Lack-of-Memory Distributions

abstract:
  We treat all the bivariate lack-of-memory (BLM) distributions in a unified
approach and develop some new general properties of the BLM distributions,
including joint moment generating function, product moments and dependence
structure. Necessary and sufficient conditions for the survival functions of
BLM distributions to be totally positive of order two are given. Some previous
results about specific BLM distributions are improved. In particular, we show
that both the Marshall--Olkin survival copula and survival function are totally
positive of all orders, regardless of parameters. Besides, we point out that
Slepian's inequality also holds true for BLM distributions.


title:
Chern insulating state in laterally patterned semiconductor
  heterostructures

abstract:
  Hexagonally patterned two-dimensional $p$-type semiconductor systems are
quantum simulators of graphene with strong and highly tunable spin-orbit
interactions. We show that application of purely in-plane magnetic fields, in
combination with the crystallographic anisotropy present in low-symmetry
semiconductor interfaces, allows Chern insulating phases to emerge from an
originally topologically insulating state after a quantum phase transition.
These phases are characterized by pairs of co-propagating edge modes and Hall
conductivities $\sigma_{xy} = +\frac{2 e^2}{h}, -\frac{2 e^2}{h}$ in the
absence of Landau levels or cyclotron motion. With current lithographic
technology, the Chern insulating transitions are predicted to occur in GaAs
heterostructures at magnetic fields of $\sim 5\text{T}$.


title:
Invariant measures for continued fraction algorithms with finitely many
  digits

abstract:
  In this paper we consider continued fraction (CF) expansions on intervals
different from $[0,1]$. For every $x$ in such interval we find a CF expansion
with a finite number of possible digits. Using the natural extension, the
density of the invariant measure is obtained in a number of examples. In case
this method does not work, a Gauss-Kuzmin-L\'evy based approximation method is
used. Finally, a subfamily of the $N$-expansions is studied. In particular, the
entropy as a function of a parameter $\alpha$ is estimated for $N=2$ and
$N=36$. Interesting behavior can be observed from numerical results.


title: PECOK: a convex optimization approach to variable clustering

abstract:
  The problem of variable clustering is that of grouping similar components of
a $p$-dimensional vector $X=(X_{1},\ldots,X_{p})$, and estimating these groups
from $n$ independent copies of $X$. When cluster similarity is defined via
$G$-latent models, in which groups of $X$-variables have a common latent
generator, and groups are relative to a partition $G$ of the index set $\{1,
\ldots, p\}$, the most natural clustering strategy is $K$-means. We explain why
this strategy cannot lead to perfect cluster recovery and offer a correction,
based on semi-definite programing, that can be viewed as a penalized convex
relaxation of $K$-means (PECOK). We introduce a cluster separation measure
tailored to $G$-latent models, and derive its minimax lower bound for perfect
cluster recovery. The clusters estimated by PECOK are shown to recover $G$ at a
near minimax optimal cluster separation rate, a result that holds true even if
$K$, the number of clusters, is estimated adaptively from the data. We compare
PECOK with appropriate corrections of spectral clustering-type procedures, and
show that the former outperforms the latter for perfect cluster recovery of
minimally separated clusters.


title:
On the spatially homogeneous and isotropic Einstein-Vlasov-Fokker-Planck
  system with cosmological scalar field

abstract:
  The Einstein-Vlasov-Fokker-Planck system describes the kinetic diffusion
dynamics of self-gravitating particles within the Einstein theory of general
relativity. We study the Cauchy problem for spatially homogeneous and isotropic
solutions and prove the existence of both global solutions and solutions that
blow-up in finite time depending on the size of certain functions of the
initial data. We also derive information on the large-time behavior of global
solutions and toward the singularity for solutions which blow-up in fine time.
Our results entail the existence of a phase of decelerated expansion followed
by a phase of accelerated expansion, in accordance with the physical
expectations in cosmology.


title:
Cooperative spontaneous emission from indistinguishable atoms in
  arbitrary motional quantum states

abstract:
  We investigate superradiance and subradiance of indistinguishable atoms with
quantized motional states, starting with an initial total state that factorizes
over the internal and external degrees of freedom of the atoms. Due to the
permutational symmetry of the motional state, the cooperative spontaneous
emission, governed by a recently derived master equation [F. Damanet et al.,
Phys. Rev. A 93, 022124 (2016)], depends only on two decay rates $\gamma$ and
$\gamma_0$ and a single parameter $\Delta_{\mathrm{dd}}$ describing the
dipole-dipole shifts. We solve the dynamics exactly for $N=2$ atoms,
numerically for up to 30 atoms, and obtain the large-$N$-limit by amean-field
approach. We find that there is a critical difference $\gamma_0-\gamma$ that
depends on $N$ beyond which superradiance is lost. We show that exact
non-trivial dark states (i.e. states other than the ground state with vanishing
spontaneous emission) only exist for $\gamma=\gamma_0$, and that those states
(dark when $\gamma=\gamma_0$) are subradiant when $\gamma<\gamma_0$.


title:
Leapfrogging vortex rings for the three dimensional Gross-Pitaevskii
  equation

abstract:
  Leapfrogging motion of vortex rings sharing the same axis of symmetry was
first predicted by Helmholtz in his famous work on the Euler equation for
incompressible fluids. Its justification in that framework remains an open
question to date. In this paper, we rigorously derive the corresponding
leapfrogging motion for the axially symmetric three-dimensional
Gross-Pitaevskii equation.


title:
The iridium double perovskite Sr2YIrO6 revisited: A combined structural
  and specific heat study

abstract:
  Recently, the iridate double perovskite Sr$_2$YIrO$_6$ has attracted
considerable attention due to the report of unexpected magnetism in this
Ir$^{5+}$ (5d$^4$) material, in which according to the J$_{eff}$ model, a
non-magnetic ground state is expected. However, in recent works on
polycrystalline samples of the series Ba$_{2-x}$Sr$_x$YIrO$_6$ no indication of
magnetic transitions have been found. We present a structural, magnetic and
thermodynamic characterization of Sr$_2$YIrO$_6$ single crystals, with emphasis
on the temperature and magnetic field dependence of the specific heat. Here, we
demonstrate the clue role of single crystal X-ray diffraction on the structural
characterization of the Sr$_2$YIrO$_6$ double perovskite crystals by reporting
the detection of a $\sqrt{2}a \times \sqrt{2}a \times 1c$ supercell, where $a$,
$b$ and $c$ are the unit cell dimensions of the reported monoclinic subcell. In
agreement with the expected non-magnetic ground state of Ir$^{5+}$ (5d$^4$) in
Sr$_2$YIrO$_6$, no magnetic transition is observed down to 430~mK. Moreover,
our results suggest that the low temperature anomaly observed in the specific
heat is not related to the onset of long-range magnetic order. Instead, it is
identified as a Schottky anomaly caused by paramagnetic impurities present in
the sample, of the order of $n \sim 0.5(2)$ \%. These impurities lead to
non-negligible spin correlations, which nonetheless, are not associated with
long-range magnetic ordering.


title:
Machine Learning Across Cultures: Modeling the Adoption of Financial
  Services for the Poor

abstract:
  Recently, mobile operators in many developing economies have launched "Mobile
Money" platforms that deliver basic financial services over the mobile phone
network. While many believe that these services can improve the lives of the
poor, a consistent difficulty has been identifying individuals most likely to
benefit from access to the new technology. Here, we combine terabyte-scale data
from three different mobile phone operators from Ghana, Pakistan, and Zambia,
to better understand the behavioral determinants of mobile money adoption. Our
supervised learning models provide insight into the best predictors of adoption
in three very distinct cultures. We find that models fit on one population fail
to generalize to another, and in general are highly context-dependent. These
findings highlight the need for a nuanced approach to understanding the role
and potential of financial services for the poor.


title:
Astrophysical applications of the post-Tolman-Oppenheimer-Volkoff
  formalism

abstract:
  The bulk properties of spherically symmetric stars in general relativity can
be obtained by integrating the Tolman-Oppenheimer-Volkoff (TOV) equations. In
previous work we developed a "post-TOV" formalism - inspired by parametrized
post-Newtonian theory - which allows us to classify in a parametrized,
phenomenological form all possible perturbative deviations from the structure
of compact stars in general relativity that may be induced by modified gravity
at second post-Newtonian order. In this paper we extend the formalism to deal
with the stellar exterior, and we compute several potential astrophysical
observables within the post-TOV formalism: the surface redshift $z_s$, the
apparent radius $R_{\rm app}$, the Eddington luminosity at infinity $L_{\rm
E}^\infty$ and the orbital frequencies. We show that, at leading order, all of
these quantities depend on just two post-TOV parameters $\mu_1$ and $\chi$, and
we discuss the possibility to measure (or set upper bounds on) these
parameters.


title:
Clustering high dimensional mixed data to uncover sub-phenotypes:joint
  analysis of phenotypic and genotypic data

abstract:
  The LIPGENE-SU.VI.MAX study, like many others, recorded high dimensional
continuous phenotypic data and categorical genotypic data. LIPGENE-SU.VI.MAX
focuses on the need to account for both phenotypic and genetic factors when
studying the metabolic syndrome (MetS), a complex disorder that can lead to
higher risk of type 2 diabetes and cardiovascular disease. Interest lies in
clustering the LIPGENE-SU.VI.MAX participants into homogeneous groups or
sub-phenotypes, by jointly considering their phenotypic and genotypic data, and
in determining which variables are discriminatory.
  A novel latent variable model which elegantly accommodates high dimensional,
mixed data is developed to cluster LIPGENE-SU.VI.MAX participants using a
Bayesian finite mixture model. A computationally efficient variable selection
algorithm is incorporated, estimation is via a Gibbs sampling algorithm and an
approximate BIC-MCMC criterion is developed to select the optimal model.
  Two clusters or sub-phenotypes (`healthy' and `at risk') are uncovered. A
small subset of variables is deemed discriminatory which notably includes
phenotypic and genotypic variables, highlighting the need to jointly consider
both factors. Further, seven years after the LIPGENE-SU.VI.MAX data were
collected, participants underwent further analysis to diagnose presence or
absence of the MetS. The two uncovered sub-phenotypes strongly correspond to
the seven year follow up disease classification, highlighting the role of
phenotypic and genotypic factors in the MetS, and emphasising the potential
utility of the clustering approach in early screening. Additionally, the
ability of the proposed approach to define the uncertainty in sub-phenotype
membership at the participant level is synonymous with the concepts of
precision medicine and nutrition.


title:
Uncertainties in the attribution of greenhouse gas warming and
  implications for climate prediction

abstract:
  Using optimal detection techniques with climate model simulations, most of
the observed increase of near surface temperatures over the second half of the
twentieth century is attributed to anthropogenic influences. However, the
partitioning of the anthropogenic influence to individual factors, such as
greenhouse gases and aerosols, is much less robust. Differences in how forcing
factors are applied, in their radiative influence and in models' climate
sensitivities, substantially influence the response patterns. We find standard
optimal detection methodologies cannot fully reconcile this response diversity.
By selecting a set of experiments to enable the diagnosing of greenhouse gases
and the combined influence of other anthropogenic and natural factors, we find
robust detections of well mixed greenhouse gases across a large ensemble of
models. Of the observed warming over the 20th century of 0.65K/century we find,
using a multi model mean not incorporating pattern uncertainty, a well mixed
greenhouse gas warming of 0.87 to 1.22K/century. This is partially offset by
cooling from other anthropogenic and natural influences of -0.54 to
-0.22K/century. Although better constrained than recent studies, the
attributable trends across climate models are still wide, with implications for
observational constrained estimates of transient climate response. Some of the
uncertainties could be reduced in future by having more model data to better
quantify the simulated estimates of the signals and natural variability, by
designing model experiments more effectively and better quantification of the
climate model radiative influences. Most importantly, how model pattern
uncertainties are incorporated into the optimal detection methodology should be
improved.


title: Laser writing of coherent colour centres in diamond

abstract:
  Optically active point defects in crystals have gained widespread attention
as photonic systems that can find use in quantum information technologies.
However challenges remain in the placing of individual defects at desired
locations, an essential element of device fabrication. Here we report the
controlled generation of single nitrogen-vacancy (NV) centres in diamond using
laser writing. The use of aberration correction in the writing optics allows
precise positioning of vacancies within the diamond crystal, and subsequent
annealing produces single NV centres with up to 45% success probability, within
about 200 nm of the desired position. Selected NV centres fabricated by this
method display stable, coherent optical transitions at cryogenic temperatures,
a pre-requisite for the creation of distributed quantum networks of solid-state
qubits. The results illustrate the potential of laser writing as a new tool for
defect engineering in quantum technologies.


title:
Machine Learning meets Data-Driven Journalism: Boosting International
  Understanding and Transparency in News Coverage

abstract:
  Migration crisis, climate change or tax havens: Global challenges need global
solutions. But agreeing on a joint approach is difficult without a common
ground for discussion. Public spheres are highly segmented because news are
mainly produced and received on a national level. Gain- ing a global view on
international debates about important issues is hindered by the enormous
quantity of news and by language barriers. Media analysis usually focuses only
on qualitative re- search. In this position statement, we argue that it is
imperative to pool methods from machine learning, journalism studies and
statistics to help bridging the segmented data of the international public
sphere, using the Transatlantic Trade and Investment Partnership (TTIP) as a
case study.


title:
Critical behavior of quantum magnets with long-range interactions in the
  thermodynamic limit

abstract:
  Quasiparticle properties of quantum magnets with long-range interactions are
investigated by high-order linked-cluster expansions in the thermodynamic
limit. It is established that perturbative continuous unitary transformations
on white graphs are a promising and flexible approach to treat long-range
interactions in quantum many-body systems. We exemplify this scheme for the
one-dimensional transverse-field Ising chain with long-range interactions. For
this model the elementary Quasiparticle gap is determined allowing to access
the quantum-critical regime including critical exponents and multiplicative
logarithmic corrections for the ferro- and antiferromagnetic case.


title: Engineering Tagging Languages for DSLs

abstract:
  To keep a DSL clean, readable and reusable in different contexts, it is
useful to define a separate tagging language. A tag model logically adds
information to the tagged DSL model while technically keeping the artifacts
separated. Using a generic tagging language leads to promiscuous tag models,
whereas defining a target DSL-specific tag language has a high initial
overhead. This paper presents a systematic approach to define a DSL-specific
tag language and a corresponding schema language, combining the advantages of
both worlds: (a) the tag language specifically fits to the DSL, (b) the
artifacts are kept separated and enabling reuse with different tag decorations,
(c) the tag language follows a defined type schema, and (d) systematic
derivation considerably reduces the effort necessary to implement the tag
language. An example shows that it can at least partially be realized by a
generator and applied for any kind of DSL. Index Terms Software Engineering,
Modeling, MDE, GSE