title:
Robust Hybrid Learning for Estimating Personalized Dynamic Treatment
  Regimens

abstract:
  Dynamic treatment regimens (DTRs) are sequential decision rules tailored at
each stage by potentially time-varying patient features and intermediate
outcomes observed in previous stages. The complexity, patient heterogeneity and
chronicity of many diseases and disorders call for learning optimal DTRs which
best dynamically tailor treatment to each individual's response over time.
Proliferation of personalized data (e.g., genetic and imaging data) provides
opportunities for deep tailoring as well as new challenges for statistical
methodology. In this work, we propose a robust hybrid approach referred as
Augmented Multistage Outcome-Weighted Learning (AMOL) to integrate
outcome-weighted learning and Q-learning to identify optimal DTRs from the
Sequential Multiple Assignment Randomization Trials (SMARTs). We generalize
outcome weighted learning (O-learning; Zhao et al.~2012) to allow for negative
outcomes; we propose methods to reduce variability of weights in O-learning to
achieve numeric stability and higher efficiency; finally, for multiple-stage
SMART studies, we introduce doubly robust augmentation to machine learning
based O-learning to improve efficiency by drawing information from regression
model-based Q-learning at each stage. The proposed AMOL remains valid even if
the Q-learning model is misspecified. We establish the theoretical properties
of AMOL, including the consistency of the estimated rules and the rates of
convergence to the optimal value function. The comparative advantage of AMOL
over existing methods is demonstrated in extensive simulation studies and
applications to two SMART data sets: a two-stage trial for attention deficit
and hyperactive disorder (ADHD) and the STAR*D trial for major depressive
disorder (MDD).


title: Learning from Untrusted Data

abstract:
  The vast majority of theoretical results in machine learning and statistics
assume that the available training data is a reasonably reliable reflection of
the phenomena to be learned or estimated. Similarly, the majority of machine
learning and statistical techniques used in practice are brittle to the
presence of large amounts of biased or malicious data. In this work we consider
two frameworks in which to study estimation, learning, and optimization in the
presence of significant fractions of arbitrary data.
  The first framework, list-decodable learning, asks whether it is possible to
return a list of answers, with the guarantee that at least one of them is
accurate. For example, given a dataset of $n$ points for which an unknown
subset of $\alpha n$ points are drawn from a distribution of interest, and no
assumptions are made about the remaining $(1-\alpha)n$ points, is it possible
to return a list of $\operatorname{poly}(1/\alpha)$ answers, one of which is
correct? The second framework, which we term the semi-verified learning model,
considers the extent to which a small dataset of trusted data (drawn from the
distribution in question) can be leveraged to enable the accurate extraction of
information from a much larger but untrusted dataset (of which only an
$\alpha$-fraction is drawn from the distribution).
  We show strong positive results in both settings, and provide an algorithm
for robust learning in a very general stochastic optimization setting. This
general result has immediate implications for robust estimation in a number of
settings, including for robustly estimating the mean of distributions with
bounded second moments, robustly learning mixtures of such distributions, and
robustly finding planted partitions in random graphs in which significant
portions of the graph have been perturbed by an adversary.


title: Randomized Model Order Reduction

abstract:
  Singular value decomposition (SVD) has a crucial role in model order
reduction. It is often utilized in the offline stage to compute basis functions
that project the high-dimensional nonlinear problem into a low-dimensionsl
model which is, then, evaluated cheaply. It constitutes a building block for
many techniques such as e.g. Proper Orthogonal Decomposition and Dynamic Mode
Decomposition. The aim of this work is to provide efficient computation of the
basis functions via randomized matrix decompositions. This is possible due to
the randomized Singular Value Decomposition (rSVD) which is a fast and accurate
alternative of the SVD. Although this is considered as offline stage, this
computation may be extremely expensive and therefore the use of compressed
techniques drastically reduce its cost. Numerical examples show the
effectiveness of the method for both Proper Orthogonal Decomposition (POD) and
Dynamic Mode Decomposition (DMD).


title: Renal Parenchymal Area and Kidney Collagen Content

abstract:
  The extent of renal scarring in chronic kidney disease (CKD) can only be
ascertained by highly invasive, painful and sometimes risky tissue biopsy.
Interestingly, CKD-related abnormalities in kidney size can often be visualized
using ultrasound. Nevertheless, not only does the ellipsoid formula used today
underestimate true renal size but also the relation governing renal size and
collagen content remains unclear. We used coronal kidney sections from healthy
mice and mice with renal disease to develop a new technique for estimating the
renal parenchymal area. While treating the kidney as an ellipse with the major
axis the polar distance, this technique involves extending the minor axis into
the renal pelvis. The calculated renal parenchymal area is remarkably similar
to the measured area. Biochemically determined kidney collagen content revealed
a strong and positive correlation with the calculated renal parenchymal area.
The extent of renal scarring, i.e. kidney collagen content, can now be computed
by making just two renal axial measurements which can easily be accomplished
via noninvasive imaging of this organ.


title: Is the line-like optical afterglow SED of GRB 050709 due to a flare?

abstract:
  Recently Jin et al. (2016) reanalyzed the optical observation data of GRB
050709 and reported a line-like spectral energy distribution (SED) component
observed by the Very Large Telescope at $t\sim 2.5$ days after the trigger of
the burst, which had been interpreted as a broadened line signal arising from a
macronova dominated by iron group. In this work we show that an optical flare
origin of such a peculiar optical SED is still possible. Interestingly, even in
such a model, an "unusual" origin of the late-time long-lasting Hubble Space
Telescope F814W-band emission is still needed and a macronova/kilonova is the
natural interpretation.


title:
Performance Improvements in Heterogeneous Wireless Networks for First
  Responders

abstract:
  Efficient communications are crucial for disaster response and recovery.
However, most current public safety land mobile radio (LMR) networks only
provide narrowband voice service with limited support of low-speed data
services. In this paper, we study to enhance the interoperability of LMR with
commercial wireless cellular networks, by which a wide variety of benefits can
be offered to disaster responders, including new multimedia services, increased
data rates and low cost devices. Our approach is based on Session Initial
Protocol (SIP) and a joint radio resource management framework. In addition, an
optimal radio resource management scheme is proposed to maximize the overall
radio resource utilization and at the same time guarantee service availability
and continuity quality of service (QoS) for disaster responders. The
effectiveness of the proposed approach is illustrated by numerical examples.


title: Adversarial Ladder Networks

abstract:
  The use of unsupervised data in addition to supervised data in training
discriminative neural networks has improved the performance of this clas-
sification scheme. However, the best results were achieved with a training
process that is divided in two parts: first an unsupervised pre-training step
is done for initializing the weights of the network and after these weights are
refined with the use of supervised data. On the other hand adversarial noise
has improved the results of clas- sical supervised learning. Recently, a new
neural network topology called Ladder Network, where the key idea is based in
some properties of hierar- chichal latent variable models, has been proposed as
a technique to train a neural network using supervised and unsupervised data at
the same time with what is called semi-supervised learning. This technique has
reached state of the art classification. In this work we add adversarial noise
to the ladder network and get state of the art classification, with several
important conclusions on how adversarial noise can help in addition with new
possible lines of investi- gation. We also propose an alternative to add
adversarial noise to unsu- pervised data.


title: Holographic Complexity and Two Identities of Action Growth

abstract:
  The recently proposed complexity-action conjecture allows one to calculate
how fast one can produce a quantum state from a reference state in terms of the
on-shell action of the dual AdS black hole at the Wheeler-DeWitt patch. We show
that the action growth rate is given by the difference of the generalized
enthalpy between the two corresponding horizons. The proof relies on the second
identity that the surface-term contribution on a horizon is given by the
product of the associated temperature and entropy.


title:
Developing skills vs reinforcing concepts in physics labs: Insight from
  E-CLASS

abstract:
  Physics laboratory courses have been generally acknowledged as an important
component of the undergraduate curriculum, particularly with respect to
developing students' interest in, and understanding of, experimental physics.
There are a number of possible learning goals for these courses including
reinforcing physics concepts, developing laboratory skills, and promoting
expert-like beliefs about the nature of experimental physics. However, there is
little consensus among instructors and researchers interested in the laboratory
learning environment as to relative importance of these various learning goals.
Here, we contribute data to this debate through the analysis of students'
responses to the laboratory-focused assessment known as the Colorado Learning
Attitudes about Science Survey for Experimental Physics (E-CLASS). Using a
large, national data set of students' responses, we compare students' E-CLASS
performance in classes in which the instructor self-reported focusing on
developing skills, reinforcing concepts, or both. As the classification of
courses was based on instructor self-report, we also provide additional
description of these course with respect to how often students engage in
particular activities in the lab. We find that courses that focus specifically
on developing lab skills have more expert-like postinstruction E-CLASS
responses than courses that focus either on reinforcing physics concepts or on
both goals. Within first-year courses, this effect is larger for women.
Moreover, these findings hold when controlling for the variance in
postinstruction scores that is associated with preinstruction E-CLASS score,
student major, and student gender.


title:
An Efficient Quasi-physical Quasi-human Algorithm for Packing Equal
  Circles in a Circular Container

abstract:
  This paper addresses the equal circle packing problem, and proposes an
efficient Quasi-physical Quasi-human (QPQH) algorithm. QPQH is based on a
modified Broyden-Fletcher-Goldfarb-Shanno (BFGS) algorithm which we call the
local BFGS and a new basin hopping strategy based on a Chinese idiom: alternate
tension with relaxation. Starting from a random initial layout, we apply the
local BFGS algorithm to reach a local minimum layout. The local BFGS algorithm
fully utilizes the neighborhood information of each circle to considerably
speed up the running time of the gradient descent process, and the efficiency
is very apparent for large scale instances. When yielding a local minimum
layout, the new basin-hopping strategy is to shrink the container size to
different extent to generate several new layouts. Experimental results indicate
that the new basin-hopping strategy is very efficient, especially for a type of
layout with comparatively dense packing in the center and comparatively sparse
packing around the boundary of the container. We test QPQH on the instances of
n = 1,2,...,320, and obtain 66 new layouts which have smaller container sizes
than the current best-known results reported in literature.


title:
Ultra-Spinning Gauged Supergravity Black Holes and their Kerr/CFT
  Correspondence

abstract:
  Recently a new class of asymptotically AdS ultra-spinning black holes has
been constructed with a noncompact horizon of finite area [1], in which the
asymptotic rotation is effectively boosted to the speed of light. We employ
this technique for four-dimensional $U(1)^4$ and five-dimensional $U(1)^3$
gauged supergravity black holes. The obtained new exact black hole solutions
for both cases possess a noncompact horizon; their topologies are a sphere with
two punctures. We then demonstrate that the ultra-spinning limit commutes with
the extremality condition as well as the near horizon limit for both black
holes. We also show that the near horizon extremal geometries of the resulting
ultra-spinning gauged supergravity black holes lead to the well-known result
which contains an AdS$_2$ throat. We then obtain the $[(d-1)/2]$ central
charges of the dual CFTs. By assuming the Cardy formula, we show that despite
the noncompactness of the horizon, microscopic entropy of the dual CFT is
precisely equivalent to the Bekenstein-Hawking entropy.


title: Chaos-based Wireless Communication Resisting Multipath Effects

abstract:
  In additive white gaussian noise (AWGN) channel, chaos has been proved to be
the optimal coherent communication waveform in the sense of using very simple
matched filter to maximize the signal-to-noise ratio (SNR). Recently, Lyapunov
exponent spectrum of the chaotic signals after being transmitted through a
wireless channel has been shown to be unaltered, paving the way for wireless
communication using chaos. In wireless communication systems, inter-symbol
interference (ISI) caused by multipath propagation is one of the main obstacles
to achieve high bit transmission rate and low bit error rate (BER). How to
resist multipath effect is a fundamental problem in a chaos-based wireless
communication system (CWCS). In this paper, implementation of a CWCS is
presented. It is built to transmit chaotic signals generated by a hybrid
dynamical system and then to filter the received signals by using the
corresponding matched filter to decrease the noise effect and to detect the
binary information. We find that the multipath effect can be effectively
resisted by regrouping the return map of the received signal and by setting the
corresponding threshold based on the available information. We show that the
optimal threshold is a function of the channel parameters and of the
transmitted information symbols. Practically, the channel parameters are
time-variant, and the future information symbols are unavailable. In this case,
a suboptimal threshold (SOT) is proposed, and the BER using the SOT is derived
analytically. Simulation results show that the CWCS achieves a remarkable
competitive performance even under inaccurate channel parameters.


title:
On bipartite distance-regular graphs with exactly two irreducible
  T-modules with endpoint 2

abstract:
  Let $\Gamma$ denote a bipartite distance-regular graph with diameter $D \ge
4$ and valency $k \ge 3$. Let $X$ denote the vertex set of $\Gamma$, and let
$A$ denote the adjacency matrix of $\Gamma$. For $x \in X$ let $T=T(x)$ denote
the subalgebra of Mat$_X(\mathbb{C}$ generated by $A, E*_0, E*s_1, \ldots,
E*_D$, where for $0 \le i \le D$, $E*_i$ represents the projection onto the
$i$th subconstituent of $\Gamma$ with respect to $x$. We refer to $T$ as the
{\em Terwilliger algebra} of $\Gamma$ with respect to $x$. An irreducible
$T$-module $W$ is said to be {\em thin} whenever dim $E*_i W \le 1$ for $0 \le
i \le D$. By the {\em endpoint} of $W$ we mean min$\{i | E*_iW \ne 0\}$. For $0
\le i \le D$, let $\Gamma_i(z)$ denote the set of vertices in $X$ that are
distance $i$ from vertex $z$. Define a parameter $\Delta_2$ in terms of the
intersection numbers by $\Delta_2 = (k-2)(c_3-1)-(c_2-1)p^2_{22}$. In this
paper we prove the following are equivalent: (i) $\Delta_2>0$ and for $2 \le i
\le D - 2$ there exist complex scalars $\alpha_i, \beta_i$ with the following
property: for all $x, y, z \in X$ such that $\partial(x, y) = 2, \: \partial(x,
z) = i, \: \partial(y, z) = i$ we have $ \alpha_i + \beta_i |\Gamma_1(x) \cap
\Gamma_1(y) \cap \Gamma_{i-1}(z)| = |\Gamma_{i-1}(x) \cap \Gamma_{i-1}(y) \cap
\Gamma_1(z)|;$ (ii) For all $x \in X$ there exist up to isomorphism exactly two
irreducible modules for the Terwilliger algebra $T(x)$ with endpoint two, and
these modules are thin.


title: The Pseudomonotone Polar for Multivalued Operators

abstract:
  In this work, we study the pseudomonotonicity of multivalued operators from
the point of view of polarity, in an analogous way as the well-known monotone
polar due to Mart\'inez-Legaz and Svaiter, and the quasimonotone polar recently
introduced by Bueno and Cotrina. We show that this new polar, adapted for
pseudomonotonicity, possesses analogous properties to the monotone and
quasimonotone polar, among which are a characterization of pseudomonotonicity,
maximality and pre-maximality. Furthermore, we characterize the notion of
$D$-maximal pseudomonotonicity introduced by Hadjisavvas. We conclude this work
studying the connections between pseudomonotonicity and variational inequality
problems.


title: Mass Predictions of Open-Flavour Hybrid Mesons from QCD Sum Rules

abstract:
  Within QCD, colourless states may be constructed corresponding to exotic
matter outside of the traditional quark model. Experiments have recently
observed tetraquark and pentaquark states, but no definitive hybrid meson
signals have been observed. With the construction of the PANDA experiment at
FAIR, and with full commissioning of the GlueX experiment at JLab expected to
be completed this year, the opportunity for the observation of hybrid mesons
has greatly increased. However, theoretical calculations are necessary to
ascertain the identity of any experimental resonances that may be observed. We
present selected QCD sum rule results from a full range of quantum numbers for
open-flavour hybrid mesons with heavy valence quark content, including
non-perturbative condensate contributions up to six-dimensions.


title:
Convergence Analysis of Iterated Best Response for a Trusted Computation
  Game

abstract:
  We introduce a game of trusted computation in which a sensor equipped with
limited computing power leverages a central node to evaluate a specified
function over a large dataset, collected over time. We assume that the central
computer can be under attack and we propose a strategy where the sensor retains
a limited amount of the data to counteract the effect of attack. We formulate
the problem as a two player game in which the sensor (defender) chooses an
optimal fusion strategy using both the non-trusted output from the central
computer and locally stored trusted data. The attacker seeks to compromise the
computation by influencing the fused value through malicious manipulation of
the data stored on the central node. We first characterize all Nash equilibria
of this game, which turn out to be dependent on parameters known to both
players. Next we adopt an Iterated Best Response (IBR) scheme in which, at each
iteration, the central computer reveals its output to the sensor, who then
computes its best response based on a linear combination of its private local
estimate and the untrusted third-party output. We characterize necessary and
sufficient conditions for convergence of the IBR along with numerical results
which show that the convergence conditions are relatively tight.


title:
On the incompleteness of Ibragimov's conservation law theorem and its
  equivalence to a standard formula using symmetries and adjoint-symmetries

abstract:
  A conservation law theorem stated by N. Ibragimov along with its subsequent
extensions are shown to be a special case of a standard formula that uses a
pair consisting of a symmetry and an adjoint-symmetry to produce a conservation
law through a well-known Fr\'echet derivative identity. Also, the connection of
this formula (and of Ibragimov's theorem) to the standard action of symmetries
on conservation laws is explained, which accounts for a number of major
drawbacks that have appeared in recent work using the formula to generate
conservation laws. In particular, the formula can generate trivial conservation
laws and does not always yield all non-trivial conservation laws unless the
symmetry action on the set of these conservation laws is transitive. It is
emphasized that all local conservation laws for any given system of
differential equations can be found instead by a general method using
adjoint-symmetries. This general method is a kind of adjoint version of the
standard Lie method to find all local symmetries and is completely algorithmic.
The relationship between this method, Noether's theorem, and the
symmetry/adjoint-symmetry formula is discussed.


title: New families of rank 2 bundles on projective space

abstract:
  We present a new family of monads whose cohomology is a stable rank two
vector bundle on $\PP$. We also study the irreducibility and smoothness
together with a geometrical description of some of these families. Such facts
are used to prove that the moduli space of stable rank two vector bundles of
zero first Chern class and second Chern class equal to 5 has exactly three
irreducible components.


title: Energy-based Analysis of Biomolecular Pathways

abstract:
  Decomposition of biomolecular reaction networks into pathways is a powerful
approach to the analysis of metabolic and signalling networks. Current
approaches based on analysis of the stoichiometric matrix reveal information
about steady-state mass flows (reaction rates) through the network. In this
work we show how pathway analysis of biomolecular networks can be extended
using an energy-based approach to provide information about energy flows
through the network. This energy-based approach is developed using the
engineering-inspired bond graph methodology to represent biomolecular reaction
networks.
  The approach is introduced using glycolysis as an exemplar; and is then
applied to analyse the efficiency of free energy transduction in a biomolecular
cycle model of a transporter protein (Sodium-Glucose Transport Protein 1,
SGLT1).
  The overall aim of our work is to present a framework for modelling and
analysis of biomolecular reactions and processes which considers energy flows
and losses as well as mass transport.


title: A binary embedding of the stable line-breaking construction

abstract:
  We embed Duquesne and Le Gall's stable tree into a binary compact continuum
random tree (CRT) in a way that solves an open problem posed by Goldschmidt and
Haas. This CRT can be obtained by applying a recursive construction method of
compact CRTs as presented in earlier work to a specific distribution of a
random string of beads, i.e. a random interval equipped with a random discrete
measure. We also express this CRT as a tree built by replacing all branch
points of a stable tree by rescaled i.i.d. copies of a Ford CRT. Some of these
developments are carried out in a space of infinity-marked metric spaces
generalising Miermont's notion of a k-marked metric space.


title:
On the location of the maximum of a process: L\'evy, Gaussian and
  multidimensional cases

abstract:
  In this short article we show how the techniques presented in arXiv:1207.4469
can be extended to a variety of non continuous and multivariate processes. As
examples, we prove uniqueness of the location of the maximum for spectrally
positive L\'evy processes, Ornstein-Uhlenbeck process, fractional Brownian
Motion and the Brownian sheet among others gaussian processes.


title:
Posterior Consistency for a Non-parametric Survival Model under a
  Gaussian Process Prior

abstract:
  In this paper, we prove almost surely consistency of a Survival Analysis
model, which puts a Gaussian process, mapped to the unit interval, as a prior
on the so-called hazard function. We assume our data is given by survival
lifetimes $T$ belonging to $\mathbb{R}^{+}$, and covariates on $[0,1]^d$, where
$d$ is an arbitrary dimension. We define an appropriate metric for survival
functions and prove posterior consistency with respect to this metric. Our
proof is based on an extension of the theorem of Schwartz (1965), which gives
general conditions for proving almost surely consistency in the setting of non
i.i.d random variables. Due to the nature of our data, several results for
Gaussian processes on $\mathbb{R}^+$ are proved which may be of independent
interest.


title:
Optimal Dynamic Point Selection for Power Minimization in Multiuser
  Downlink CoMP

abstract:
  This paper examines a CoMP system where multiple base-stations (BS) employ
coordinated beamforming to serve multiple mobile-stations (MS). Under the
dynamic point selection mode, each MS can be assigned to only one BS at any
time. This work then presents a solution framework to optimize the BS
associations and coordinated beamformers for all MSs. With target
signal-to-interference-plus-noise ratios at the MSs, the design objective is to
minimize either the weighted sum transmit power or the per-BS transmit power
margin. Since the original optimization problems contain binary variables
indicating the BS associations, finding their optimal solutions is a
challenging task. To circumvent this difficulty, we first relax the original
problems into new optimization problems by expanding their constraint sets.
Based on the nonconvex quadratic constrained quadratic programming framework,
we show that these relaxed problems can be solved optimally. Interestingly,
with the first design objective, the obtained solution from the relaxed problem
is also optimal to the original problem. With the second design objective, a
suboptimal solution to the original problem is then proposed, based on the
obtained solution from the relaxed problem. Simulation results show that the
resulting jointly optimal BS association and beamforming design significantly
outperforms fixed BS association schemes.


title: Balotage in Argentina 2015, a sentiment analysis of tweets

abstract:
  Twitter social network contains a large amount of information generated by
its users. That information is composed of opinions and comments that may
reflect trends in social behavior. There is talk of trend when it is possible
to identify opinions and comments geared towards the same shared by a lot of
people direction. To determine if two or more written opinions share the same
address, techniques Natural Language Processing (NLP) are used. This paper
proposes a methodology for predicting reflected in Twitter from the use of
sentiment analysis functions NLP based on social behaviors. The case study was
selected the 2015 Presidential in Argentina, and a software architecture Big
Data composed Vertica data base with the component called Pulse was used.
Through the analysis it was possible to detect trends in voting intentions with
regard to the presidential candidates, achieving greater accuracy in predicting
that achieved with traditional systems surveys.


title: Line failure probability bounds for power grids

abstract:
  We develop upper bounds for line failure probabilities in power grids, under
the DC approximation and assuming Gaussian noise for the power injections. Our
upper bounds are explicit, and lead to characterization of safe operational
capacity regions that are convex and polyhedral, making our tools compatible
with existing planning methods. Our probabilistic bounds are derived through
the use of powerful concentration inequalities.


title:
Toughening by crack deflection in the homogenization of brittle
  composites with soft inclusions

abstract:
  We present a simple example of toughening mechanism in the homogenization of
composites with soft inclusions, produced by crack deflection at microscopic
level. We show that the mechanism is connected to the irreversibility of the
crack process. Because of that it cannot be detected through the standard
homogenization tool of the $\Gamma$-convergence.


title:
The theory of the Double Solution: Dynamical issues in quantum systems
  in the semiclassical regime

abstract:
  The "dynamical mismatch" observed in quantum systems in the semiclassical
regime challenge the Pilot wave model. Indeed the dynamics and properties of
such systems depend on the trajectories of the classically equivalent system,
whereas the de Broglie-Bohm trajectories are generically non-classical.\ In
this work we examine the situation for the model favoured by de Broglie, the
theory of the Double Solution (DS). We will see that the original DS model
applied to semiclassical systems is also prone to the dynamical mismatch.\
However we will argue that the DS theory can be modified in order to yield
propagation of the singularity in accord with the underlying classical dynamics
of semiclassical systems.


title:
New bounds for locally irregular chromatic index of bipartite and
  subcubic graphs

abstract:
  A graph is \textit{locally irregular} if the neighbors of every vertex $v$
have degrees distinct from the degree of $v$. \textit{locally irregular
edge-coloring} of a graph $G$ is an (improper) edge-coloring such that the
graph induced on the edges of any color class is locally irregular. It is
conjectured that $3$ colors suffice for a locally irregular edge-coloring.
Recently, Bensmail et al. (Bensmail, Merker, Thomassen: Decomposing graphs into
a constant number of locally irregular subgraphs, {\em European J. Combin.},
60:124--134, 2017) settled the first constant upper bound for the problem to
$328$ colors. In this paper, using a combination of existing results, we
present an improvement of the bounds for bipartite graphs and general graphs,
setting the best upper bounds to $7$ and $220$, respectively. In addition, we
also prove that $4$ colors suffice for locally irregular edge-coloring of any
subcubic graph.


title:
Localizing virtual fundamental cycles for semi-perfect obstruction
  theories

abstract:
  Recently H.-L. Chang and J. Li generalized the theory of virtual fundamental
class to the setting of semi-perfect obstruction theory. A semi-perfect
obstruction theory requires only the local existence of a perfect obstruction
theory with compatibility conditions. In this paper, we generalize the torus
localization, the cosection localization and their combination, to the setting
of semi-perfect obstruction theory. As an application, we show that the
Jiang-Thomas theory of virtual signed Euler characteristic works without the
technical quasi-smoothness assumption from derived algebraic geometry.


title: Non-Myopic Target Tracking Strategies for State-Dependent Noise

abstract:
  We study the problem of devising a closed-loop strategy to control the
position of a robot that is tracking a possibly moving target. The robot is
capable of obtaining noisy measurements of the target's position. The key idea
in active target tracking is to choose control laws that drive the robot to
measurement locations that will reduce the uncertainty in the target's
position. The challenge is that measurement uncertainty often is a function of
the (unknown) relative positions of the target and the robot. Consequently, a
closed-loop control policy is desired which can map the current estimate of the
target's position to an optimal control law for the robot.
  Our main contribution is to devise a closed-loop control policy for target
tracking that plans for a sequence of control actions, instead of acting
greedily. We consider scenarios where the noise in measurement is a function of
the state of the target. We seek to minimize the maximum uncertainty (trace of
the posterior covariance matrix) over all possible measurements. We exploit the
structural properties of a Kalman Filter to build a policy tree that is orders
of magnitude smaller than naive enumeration while still preserving optimality
guarantees. We show how to obtain even more computational savings by relaxing
the optimality guarantees. The resulting algorithms are evaluated through
simulations.


title: A Convolutional Encoder Model for Neural Machine Translation

abstract:
  The prevalent approach to neural machine translation relies on bi-directional
LSTMs to encode the source sentence. In this paper we present a faster and
simpler architecture based on a succession of convolutional layers. This allows
to encode the entire source sentence simultaneously compared to recurrent
networks for which computation is constrained by temporal dependencies. On
WMT'16 English-Romanian translation we achieve competitive accuracy to the
state-of-the-art and we outperform several recently published results on the
WMT'15 English-German task. Our models obtain almost the same accuracy as a
very deep LSTM setup on WMT'14 English-French translation. Our convolutional
encoder speeds up CPU decoding by more than two times at the same or higher
accuracy as a strong bi-directional LSTM baseline.


title:
Neural Taylor Approximations: Convergence and Exploration in Rectifier
  Networks

abstract:
  Modern convolutional networks, incorporating rectifiers and max-pooling, are
neither smooth nor convex; standard guarantees therefore do not apply.
Nevertheless, methods from convex optimization such as gradient descent and
Adam are widely used as building blocks for deep learning algorithms. This
paper provides the first convergence guarantee applicable to modern convnets,
which furthermore matches a lower bound for convex nonsmooth functions. The key
technical tool is the neural Taylor approximation -- a straightforward
application of Taylor expansions to neural networks -- and the associated
Taylor loss. Experiments on a range of optimizers, layers, and tasks provide
evidence that the analysis accurately captures the dynamics of neural
optimization. The second half of the paper applies the Taylor approximation to
isolate the main difficulty in training rectifier nets -- that gradients are
shattered -- and investigates the hypothesis that, by exploring the space of
activation configurations more thoroughly, adaptive optimizers such as RMSProp
and Adam are able to converge to better solutions.


title: A versatile, inexpensive integrated photonics platform

abstract:
  We present an approach to fabrication and packaging of integrated photonic
devices that utilizes waveguide and detector layers deposited at near-ambient
temperature. All lithography is performed with a 365 nm i-line stepper,
facilitating low cost and high scalability. We have shown low-loss SiN
waveguides, high-$Q$ ring resonators, critically coupled ring resonators, 50/50
beam splitters, Mach-Zehnder interferometers (MZIs) and a process-agnostic
fiber packaging scheme. We have further explored the utility of this process
for applications in nonlinear optics and quantum photonics. We demonstrate
spectral tailoring and octave-spanning supercontinuum generation as well as the
integration of superconducting nanowire single photon detectors with MZIs and
channel-dropping filters. The packaging approach is suitable for operation up
to 160 \degree C as well as below 1 K. The process is well suited for
augmentation of existing foundry capabilities or as a stand-alone process.


title:
Centro-affine invariants and the canonical Lorentz metric on the space
  of centered ellipses

abstract:
  We consider smooth plane curves which are convex with respect to the origin.
We describe centro-affine invariants (that is, GL_+(2,R)-invariants), such as
centro-affine curvature and arc length, in terms of the canonical Lorentz
structure on the three dimensional space of all the ellipses centered at zero,
by means of null curves of osculating ellipses. This is the centro-affine
analogue of the approach to conformal invariants of curves in the sphere
introduced by Langevin and O'Hara, using the canonical pseudo Riemannian metric
on the space of circles.


title:
A structure preserving Lanczos algorithm for computing the optical
  absorption spectrum

abstract:
  We present a new structure preserving Lanczos algorithm for approximating the
optical absorption spectrum in the context of solving full Bethe--Salpeter
equation without Tamm--Dancoff approximation. The new algorithm is based on a
structure preserving Lanczos procedure, which exploits the special block
structure of Bethe--Salpeter Hamiltonian matrices. A recently developed
technique of generalized averaged Gauss quadrature is incorporated to
accelerate the convergence. We also establish the connection between our
structure preserving Lanczos procedure with several existing Lanczos procedures
developed in different contexts. Numerical examples are presented to
demonstrate the effectiveness of our Lanczos algorithm.


title:
Heteroclinic Cycles in Systems with
  $\mathbb{Z}_2\times\mathbb{Z}_2\times\mathbb{Z}_2$ Symmetry, Revisited

abstract:
  We analyze the generating mechanisms for heteroclinic cycles in
$\mathbb{Z}_2\times\mathbb{Z}_2\times\mathbb{Z}_2$--equivariant ODEs, not
involving Hopf bifurcations. Such cycles have been observed in particle physics
systems with the mentioned symmetry, in absence of the Hopf bifurcation, see
\cite{bury} and \cite{Park}, and as far as we know, there is no available
theoretical data explaining these phenomena. We use singularity theory to study
the equivalence in the group-symmetric context, as well as the recognition
problem for the simplest bifurcation problems with this symmetry group.
Singularity results highlight different mechanisms for the appearance of
heteroclinic cycles, based on the transition between the bifurcating branches.
On the other hand, we analyze the heteroclinic cycle of a generic dynamical
system with the symmetry of the group
$\mathbb{Z}_2\times\mathbb{Z}_2\times\mathbb{Z}_2$ acting on a
eight--dimensional torus $\mathbb{T}^8,$ constructed via a Cayley graph, under
weak coupling. We identify the conditions for heteroclinic cycle between four
equilibria in the three--dimensional fixed point subspaces of some of the
isotropy subgroups of
$\mathbb{Z}_2\times\mathbb{Z}_2\times\mathbb{Z}_2\times\mathbb{S}^1.$ We also
analyze the stability of the heteroclinic cycle.


title: Synchronization of linear systems via relative actuation

abstract:
  Synchronization in networks of discrete-time linear time-invariant systems is
considered under relative actuation. Neither input nor output matrices are
assumed to be commensurable. A distributed algorithm that ensures
synchronization via dynamic relative output feedback is presented.


title:
Chain Reduction Preserves the Unrooted Subtree Prune-and-Regraft
  Distance

abstract:
  The subtree prune-and-regraft (SPR) distance metric is a fundamental way of
comparing evolutionary trees. It has wide-ranging applications, such as to
study lateral genetic transfer, viral recombination, and Markov chain Monte
Carlo phylogenetic inference. Although the rooted version of SPR distance can
be com puted relatively efficiently between rooted trees using
fixed-parameter-tractable algorithms, in the unrooted case previous algorithms
are unable to compute distances larger than 7. One important tool for efficient
computation in the rooted case is called chain reduction, which replaces an
arbitrary chain of subtrees identical in both trees with a chain of three
leaves. Whether chain reduction preserves SPR distance in the unrooted case has
remained an open question since it was conjectured in 2001 by Allen and Steel,
and was presented as a challenge question at the 2007 Isaac Newton Institute
for Mathematical Sciences program on phylogenetics.
  In this paper we prove that chain reduction preserves the unrooted SPR
distance. We do so by introducing a structure called a socket agreement forest
that restricts edge modification to predetermined socket vertices, permitting
detailed analysis and modification of SPR move sequences. This new chain
reduction theorem reduces the unrooted distance problem to a linear size
problem kernel, substantially improving on the previous best quadratic size
kernel.


title:
Contact angle entropy and macroscopic friction in non-cohesive two
  dimensional granular packings

abstract:
  We study the relationship between the granular contact angle distribution and
local particle friction on the macroscopic friction and bulk modulus in
non-cohesive disk packings. Molecular dynamics in two dimensions are used to
simulate uniaxial loading-unloading cycles imposed on the granular packings.
While macroscopic Mohr-friction depends on the granular pack geometric details,
it reaches a stationary limit after a finite number of loading-unloading cycles
that render well-defined values for bulk modulus, grain coordination, porosity,
and friction. For random packings and for all polydispersities analyzed, we
found that as inter-particle friction increases, the bulk modulus for the limit
cycle decreases linearly, while the mean coordination number is reduced and the
porosity increased, also as approximately linear functions. On the other hand,
the macroscopic Mohr-friction increases in a monotonous trend with
inter-particle friction. The latter result is compared to a theoretical model
which assumes the existence of sliding planes corresponding to definite
Mohr-friction values. The simulation results for macroscopic friction are well
described by the theoretical model that incorporates the local neighbour angle
distribution that can be quantified through the contact angle entropy. As local
friction is increased, the limit entropy of the neighbour angle distribution is
reduced, thus introducing the geometric component to granular friction.
Surprisingly, once the limit cycle is reached, the Mohr-friction seem to be
insensitive to polydispersity as has been recently reported.


title:
Enhanced Higgs associated production with a top quark pair in the NMSSM
  with light singlets

abstract:
  Precision measurements of the 125 GeV Higgs resonance recently discovered at
the LHC have determined that its properties are similar to the ones of the
Standard Model (SM) Higgs boson. However, the current uncertainties in the
determination of the Higgs boson couplings leave room for significant
deviations from the SM expectations. In fact, if one assumes no correlation
between the top-quark and gluon couplings to the Higgs, the current global fit
to the Higgs data lead to central values of the Higgs couplings to the
bottom-quark and the top-quark that are about 2 $\sigma$ away from the SM
predictions. In a previous work, we showed that such a scenario could be
realized in the Next to Minimal Supersymmetric extension of the SM (NMSSM), for
heavy singlets and light MSSM-like Higgs bosons and scalar top quarks, but for
couplings that ruined the perturbative consistency of the theory up to the GUT
scale. In this work we show that a perturbative consistent scenario, for
somewhat heavier stops, may be obtained in the presence of light singlets. An
interesting bonus of this scenario is the possibility of explaining an excess
of events observed in CP-even Higgs searches at LEP2.


title: On a condition equivalent to the Maximum Distance Separable conjecture

abstract:
  We denote by $\mathcal{P}_q$ the vector space of functions from a finite
field $\mathbb{F}_q$ to itself, which can be represented as the space
$\mathcal{P}_q := \mathbb{F}_q[x]/(x^q-x)$ of polynomial functions. We denote
by $\mathcal{O}_n \subset \mathcal{P}_q$ the set of polynomials that are either
the zero polynomial, or have at most $n$ distinct roots in $\mathbb{F}_q$.
Given two subspaces $Y,Z$ of $\mathcal{P}_q$, we denote by $\langle Y,Z
\rangle$ their span. We prove that the following are equivalent.
  A) Let $k, q$ integers, with $q$ a prime power and $2 \leq k \leq q$. Suppose
that either:
  1) $q$ is odd
  2) $q$ is even and $k \not\in \{3, q-1\}$.
  Then there do not exist distinct subspaces $Y$ and $Z$ of $\mathcal{P}_q$
such that:
  1') $dim(\langle Y, Z \rangle) = k$
  2') $dim(Y) = dim(Z) = k-1$.
  3') $\langle Y, Z \rangle \subset \mathcal{O}_{k-1}$
  4') $Y, Z \subset \mathcal{O}_{k-2}$
  5') $Y\cap Z \subset \mathcal{O}_{k-3}$.
  B) The MDS conjecture is true for the given $(q,k)$.


title:
Low-Complexity QoS-Aware Coordinated Scheduling for Heterogenous
  Networks

abstract:
  In this paper, we consider a heterogenous network (HetNet), where low-power
indoor femtocells are deployed in the coverage area of the existing macro base
station (MBS). This paper proposes a novel coordinated random beamforming and
user scheduling strategy to improve the throughput of users served by the
femtocell access point (FAP) while satisfying the quality-of-service (QoS)
requirements of users served by both MBS and FAP. The strategy, termed as
QoS-Aware Coodinated Scheduling (QACS), requires limited coordination between
the MBS and FAP, i.e., only the indexes of the qualified beams are shared.
Exact statistical analysis for the ergodic achievable rate of both FAP and MBS
with the proposed strategy are presented. Scheduling fairness is also addressed
for the proposed QACS.


title: Critical behavior of mean-field XY and related models

abstract:
  We discuss spin models on complete graphs in the mean-field (infinite-vertex)
limit, especially the classical XY model, the Toy model of the Higgs sector,
and related generalizations. We present a number of results coming from the
theory of large deviations and Stein's method, in particular, Cram\'er and
Sanov-type results, limit theorems with rates of convergence, and phase
transition behavior for these models.


title: Infinite dimensional Hilbert tensors on spaces of analytic functions

abstract:
  In this paper, the $m-$order infinite dimensional Hilbert tensor
(hypermatrix) is intrduced to define an $(m-1)$-homogeneous operator on the
spaces of analytic functions, which is called Hilbert tensor operator. The
boundedness of Hilbert tensor operator is presented on Bergman spaces $A^p$
($p>2(m-1)$). On the base of the boundedness, two positively homogeneous
operators are introduced to the spaces of analytic functions, and hence the
upper bounds of norm of such two operators are found on Bergman spaces $A^p$
($p>2(m-1)$). In particular, the norms of such two operators on Bergman spaces
$A^{4(m-1)}$ are smaller than or equal to $\pi$ and $\pi^\frac1{m-1}$,
respectively.


title: Transport signatures in topological systems coupled to AC fields

abstract:
  We study the transport properties of a topological system coupled to an AC
electric field by means of Floquet-Keldysh formalism. We consider a
semi-infinite chain of dimers coupled to a semi-infinite metallic lead, and
obtain the density of states and current when the system is out of equilibrium.
Our formalism is non-perturbative and allows us to explore, in the
thermodynamic limit, a wide range of regimes for the AC field, arbitrary values
of the coupling strength to the metallic contact and corrections to the
wide-band limit. We find that hybridization with the contact can change the
dimerization phase, and that the current dependence on the field amplitude can
be used to discriminate between them. We also show the appearance of side-bands
and non-equilibrium zero-energy modes, characteristic of Floquet systems. Our
results directly apply to the stability of non-equilibrium topological phases,
when transport measurements are used for their detection.


title:
Thermal and Magnetic Properties of Nanostructured Ferrimagnetic
  Composites with Graphene - Graphite Fillers

abstract:
  We report the results of an experimental study of thermal and magnetic
properties of nanostructured ferrimagnetic iron oxide composites with graphene
and graphite fillers synthesized via the current activated pressure assisted
densification. The thermal conductivity was measured using the laser-flash and
transient plane source techniques. It was demonstrated that addition of 5 wt. %
of equal mixture of graphene and graphite flakes to the composite results in a
factor of x2.6 enhancement of the thermal conductivity without significant
degradation of the saturation magnetization. The microscopy and spectroscopic
characterization reveal that sp2 carbon fillers preserve their crystal
structure and morphology during the composite processing. The strong increase
in the thermal conductivity was attributed to the excellent phonon heat
conduction properties of graphene and graphite. The results are important for
energy and electronic applications of the nanostructured permanent magnets.


title: Cruciform: Solving Crosswords with Natural Language Processing

abstract:
  Crossword puzzles are popular word games that require not only a large
vocabulary, but also a broad knowledge of topics. Answering each clue is a
natural language task on its own as many clues contain nuances, puns, or
counter-intuitive word definitions. Additionally, it can be extremely difficult
to ascertain definitive answers without the constraints of the crossword grid
itself. This task is challenging for both humans and computers. We describe
here a new crossword solving system, Cruciform. We employ a group of natural
language components, each of which returns a list of candidate words with
scores when given a clue. These lists are used in conjunction with the fill
intersections in the puzzle grid to formulate a constraint satisfaction
problem, in a manner similar to the one used in the Dr. Fill system. We
describe the results of several of our experiments with the system.


title:
Dependency Sensitive Convolutional Neural Networks for Modeling
  Sentences and Documents

abstract:
  The goal of sentence and document modeling is to accurately represent the
meaning of sentences and documents for various Natural Language Processing
tasks. In this work, we present Dependency Sensitive Convolutional Neural
Networks (DSCNN) as a general-purpose classification system for both sentences
and documents. DSCNN hierarchically builds textual representations by
processing pretrained word embeddings via Long Short-Term Memory networks and
subsequently extracting features with convolution operators. Compared with
existing recursive neural models with tree structures, DSCNN does not rely on
parsers and expensive phrase labeling, and thus is not restricted to
sentence-level tasks. Moreover, unlike other CNN-based models that analyze
sentences locally by sliding windows, our system captures both the dependency
information within each sentence and relationships across sentences in the same
document. Experiment results demonstrate that our approach is achieving
state-of-the-art performance on several tasks, including sentiment analysis,
question type classification, and subjectivity classification.


title:
Largest Particle Simulations Downgrade the Runaway Electron Risk for
  ITER

abstract:
  Fusion energy will be the ultimate clean energy source for mankind. One of
the most visible concerns of the future fusion device is the threat of
deleterious runaway electrons (REs) produced during unexpected disruptions of
the fusion plasma. Both efficient long-term algorithms and super-large scale
computing power are necessary to reveal the complex dynamics of REs in a
realistic fusion reactor. In the present study, we deploy the world's fastest
supercomputer, Sunway TaihuLight, and the newly developed relativistic
volume-preserving algorithm to carry out long-term particle simulations of 10^7
sampled REs in 6D phase space, which involves simulation scale of 10^18
particle-steps, the largest ever achieved in fusion research. Our simulations
show that in a realistic fusion reactor, the concern of REs is not as serious
as previously thought. Specifically, REs are confined much better than
previously predicted and the maximum average energy is in the range of 150MeV,
less than half of previous estimate.


title: Symplectic neighborhood of crossing divisors

abstract:
  This paper presents a proof of the existence of standard symplectic
coordinates near a set of smooth, orthogonally intersecting symplectic
submanifolds. It is a generalization of the standard symplectic neighborhood
theorem. Moreover, in the presence of a compact Lie group $G$ acting
symplectically, the coordinates can be chosen to be $G$-equivariant.


title:
Multiple Object Tracking with Kernelized Correlation Filters in Urban
  Mixed Traffic

abstract:
  Recently, the Kernelized Correlation Filters tracker (KCF) achieved
competitive performance and robustness in visual object tracking. On the other
hand, visual trackers are not typically used in multiple object tracking. In
this paper, we investigate how a robust visual tracker like KCF can improve
multiple object tracking. Since KCF is a fast tracker, many can be used in
parallel and still result in fast tracking. We build a multiple object tracking
system based on KCF and background subtraction. Background subtraction is
applied to extract moving objects and get their scale and size in combination
with KCF outputs, while KCF is used for data association and to handle
fragmentation and occlusion problems. As a result, KCF and background
subtraction help each other to take tracking decision at every frame. Sometimes
KCF outputs are the most trustworthy (e.g. during occlusion), while in some
other case, it is the background subtraction outputs. To validate the
effectiveness of our system, the algorithm is demonstrated on four urban video
recordings from a standard dataset. Results show that our method is competitive
with state-of-the-art trackers even if we use a much simpler data association
step.


title: NonSTOP: A NonSTationary Online Prediction Method for Time Series

abstract:
  We present online prediction methods for time series that let us explicitly
handle nonstationary artifacts (e.g. trend and seasonality) present in most
real time series. Specifically, we show that applying appropriate
transformations to such time series before prediction can lead to improved
theoretical and empirical prediction performance. Moreover, since these
transformations are usually unknown, we employ the learning with experts
setting to develop a fully online method (NonSTOP-NonSTationary Online
Prediction) for predicting nonstationary time series. This framework allows for
seasonality and/or other trends in univariate time series and cointegration in
multivariate time series. Our algorithms and regret analysis subsume recent
related work while significantly expanding the applicability of such methods.
For all the methods, we provide sub-linear regret bounds using relaxed
assumptions. The theoretical guarantees do not fully capture the benefits of
the transformations, thus we provide a data-dependent analysis of the
follow-the-leader algorithm that provides insight into the success of using
such transformations. We support all of our results with experiments on
simulated and real data.


title:
Laguerre-Gauss beam generation in IR and UV by subwavelength
  surface-relief gratings

abstract:
  The angular momentum of light can be described by the states of spin angular
momentum, associated with polarization, and orbital angular momentum, related
to the helical structure of the wave front. Laguerre-Gaussian beams carry
orbital angular momentum and their generation can be done by using an optical
device known as q-plate. However, due to the usage of liquid crystals, these
components may be restricted to operate in specific wavelengths and low power
sources. Here we present the fabrication and characterization of q-plates made
without liquid crystals, using processes of e-beam lithography, atomic layer
depositions and dry etch techniques. We exploit the phenomenon of form
birefringence to give rise to the spin-to-orbital angular momentum conversion.
We demonstrate that these plates can generate beams with high quality for the
UV and IR range, allowing them to interact with high power laser sources or
inside laser cavities.


title: Discussion of: "A Bayesian information criterion for singular models"

abstract:
  Contributed discussion to the paper of Drton and Plummer (2017), presented
before the Royal Statistical Society on 5th October 2016.


title:
Spectroscopic Comparison of Metal-Rich RRab Stars of the Galactic Field
  with Their Metal-Poor Counterparts

abstract:
  We investigate atmospheric properties of 35 stable RRab stars that possess
the full ranges of period, light amplitude, and metal abundance found in
Galactic RR Lyrae stars. Our results are derived from several thousand echelle
spectra obtained over several years with the du Pont telescope of Las Campanas
Observatory. Radial velocities of metal lines and the Halpha line were used to
construct curves of radial velocity versus pulsation phase. From these we
estimated radial velocity amplitudes for metal lines (formed near the
photosphere) and Halpha Doppler cores (formed at small optical depths). We also
measured Halpha emission fluxes when they appear during primary light rises.
Spectra shifted to rest wavelengths, binned into small phase intervals, and
coadded were used to perform model atmospheric and abundance analyses. The
derived metallicities and those of some previous spectroscopic surveys were
combined to produce a new calibration of the Layden abundance scale. We then
divided our RRab sample into metal-rich (disk) and metal-poor (halo) groups at
[Fe/H]=-1.0. The atmospheres of RRab families, so defined, differ with respect
to (a) peak strength of Halpha emission flux, (b) Halpha radial velocity
amplitude, (c) dynamical gravity, (d) stellar radius variation, (e) secondary
acceleration during the photometric "bump" that precedes minimum light, and (g)
duration of Halpha line-doubling. We also detected Halpha line-doubling during
the bump in the metal-poor family, but not in the metal-rich one. Though all
RRab probably are core helium-burning horizontal branch stars, the metal-rich
group appear to be a species sui generis.


title:
Prediction of anomalous $\Upsilon(5S)\to\Upsilon(1^3D_J)\eta$
  transitions

abstract:
  In this work, we study the hadronic loop contribution to the $\Upsilon(5S)\to
\Upsilon(1^3D_J)\eta$ ($J=1,2,3$) transitions. We predict that the branching
ratios of $\Upsilon(5S)\to \Upsilon(1^3D_1)\eta$, $\Upsilon(5S)\to
\Upsilon(1^3D_2)\eta$ and $\Upsilon(5S)\to \Upsilon(1^3D_3)\eta$ can reach up
to $(0.5\sim5.1)\times10^{-3}$, $(0.7\sim7.5)\times10^{-3}$ and
$(0.9\sim9.6)\times10^{-4}$, respectively. Since these predicted hadronic
transitions of $\Upsilon(5S)$ are comparable with these observed
$\Upsilon(5S)\to \Upsilon(nS)\pi^+\pi^-$ $(n=1,2,3)$, we suggest future
experiment like Belle and BelleII to carry out the search for these anomalous
$\Upsilon(5S)\to \Upsilon(1^3D_J)\eta$ transitions.


title:
Fingerprinting OpenFlow controllers: The first step to attack an SDN
  control plane

abstract:
  Software-Defined Networking (SDN) controllers are considered as Network
Operating Systems (NOSs) and often viewed as a single point of failure.
Detecting which SDN controller is managing a target network is a big step for
an attacker to launch specific/effective attacks against it. In this paper, we
demonstrate the feasibility of fingerpirinting SDN controllers. We propose
techniques allowing an attacker placed in the data plane, which is supposed to
be physically separate from the control plane, to detect which controller is
managing the network. To the best of our knowledge, this is the first work on
fingerprinting SDN controllers, with as primary goal to emphasize the necessity
to highly secure the controller. We focus on OpenFlow-based SDN networks since
OpenFlow is currently the most deployed SDN technology by hardware and software
vendors.


title:
Number of points of a nonsingular hypersurface in an odd-dimensional
  projective space

abstract:
  The numbers of $\mathbb{F}_q$-points of nonsingular hypersurfaces of a fixed
degree in an odd-dimensional projective space are investigated, and an upper
bound for them is given. Also we give the complete list of nonsingular
hypersurfaces each of which realizes the upper bound. This is a natural
generalization of our previous study of surfaces in projective $3$-space.


title:
Magnetic Transitions in the Chiral Armchair-Kagome System
  Mn$_2$Sb$_2$O$_7$

abstract:
  The competition between interactions in frustrated magnets allows a wide
variety of new ground states, often exhibiting emergent physics and unique
excitations. Expanding the suite of lattices available for study enhances our
chances of finding exotic physics. Mn$_2$Sb$_2$O$_7$ forms in a chiral,
kagome-based structure in which a fourth member is added to the kagome-plane
triangles to form an armchair unit and link adjacent kagome planes. This
structural motif may be viewed as intermediate between the triangles of the
kagome network and the tetrahedra in the pyrochlore lattice. Mn$_2$Sb$_2$O$_7$
exhibits two distinct magnetic phase transitions, at 11.1 and 14.2K, at least
one of which has a weak ferromagnetic component. The magnetic propagation
vector does not change through the lower transition, suggesting a metamagnetic
transition or a transition involving a multi-component order parameter.
Although previously reported in the $P3_121$ space group, Mn$_2$Sb$_2$O$_7$
actually crystallizes in $P2$, which allows ferroelectricity, and we show clear
evidence of magnetoelectric coupling indicative of multiferroic order. The
quasi-two-dimensional `armchair-kagome' lattice presents a promising platform
for probing chiral magnetism and the effect of dimensionality in highly
frustrated systems.


title: Topological protection of photonic mid-gap cavity modes

abstract:
  Defect modes in two-dimensional periodic photonic structures have found use
in a highly diverse set of optical devices. For example, photonic crystal
cavities confine optical modes to subwavelength volumes and can be used for
Purcell enhancement of nonlinearity, lasing, and cavity quantum
electrodynamics. Photonic crystal fiber defect cores allow for supercontinuum
generation and endlessly-single-mode fibers with large cores. However, these
modes are notoriously fragile: small changes in the structure can lead to
significant detuning of resonance frequency and mode volume. Here, we show that
a photonic topological crystalline insulator structure can be used to
topologically protect the resonance frequency to be in the middle of the band
gap, and therefore minimize the mode volume of a two-dimensional photonic
defect mode. We experimentally demonstrate this in a femtosecond-laser-written
waveguide array, a geometry akin to a photonic crystal fiber. The topological
defect modes are determined by a topological invariant that protects
zero-dimensional states (defect modes) embedded in a two-dimensional
environment; a novel form of topological protection that has not been
previously demonstrated.


title:
Photodetecting and Light-Emitting Devices Based on Two Dimensional
  Materials

abstract:
  Two dimensional (2D) materials, e.g. graphene, transition metal
dichalcogenides (TMDs), black phosphorus (BP), have demonstrated fascinating
electrical and optical characteristics and exhibited great potential in
optoelectronic applications. High performance and multifunctional devices were
achieved by employing diverse designs of architectures, such as hybrid systems
with nanostructured materials, bulk semiconductors and organics, forming 2D
heterostructures. In this review, we mainly discuss the recent progresses of 2D
materials in high responsive photodetectors, light-emitting devices and single
photon emitters. Hybrid systems and van der Waals heterostructures based
devices are emphasized, which exhibit great potential in state-of-the-art
applications.


title:
Modeling and analysis of the electromechanical behavior of
  surface-bonded piezoelectric actuators using finite element method

abstract:
  Piezoelectric actuators have been widely used to form a self-monitoring smart
system to do Structural health monitoring (SHM). One of the most fundamental
issues in using actuators is to determine the actuation effects being
transferred from the actuators to the host structure. This report summaries the
state of the art of modeling techniques for piezoelectric actuators and
provides a numerical analysis of the static and dynamic electromechanical
behavior of piezoelectric actuators surface-bonded to an elastic medium under
in-plane mechanical and electric loads using finite element method. Also case
study is conducted to study the effect of material properties, bonding layer
and loading frequency using static and harmonic analysis of ANSYS. Finally,
stresses and displacements are determined, and singularity behavior at the tips
of the actuator is proved. The results indicate that material properties,
bonding layers and frequency have a significant influence on the stresses
transferred to the host structure.


title: Throwing a Ball as Far as Possible, Revisited

abstract:
  What initial trajectory angle maximizes the arc length of an ideal
projectile? We show the optimal angle, which depends neither on the initial
speed nor on the acceleration of gravity, is the solution x to a surprising
transcendental equation: csc(x) = coth(csc(x)), i.e., x = arccsc(y) where y is
the unique positive fixed point of coth. Numerically, $x \approx 0.9855 \approx
56.47^\circ$. The derivation involves a nice application of differentiation
under the integral sign.


title:
Bernoulli, poly-Bernoulli, and Cauchy polynomials in terms of Stirling
  and r-Stirling numbers

abstract:
  In this short review we discuss some results on the representation of
Bernoulli, poly-Bernoulli, and Cauchy polynomials in terms of Stirling numbers
and in terms of r-Stirling numbers. Representation of higher order Bernoulli
numbers in terms of Stirling numbers is also included.


title: A Surrogate-based Generic Classifier for Chinese TV Series Reviews

abstract:
  With the emerging of various online video platforms like Youtube, Youku and
LeTV, online TV series' reviews become more and more important both for viewers
and producers. Customers rely heavily on these reviews before selecting TV
series, while producers use them to improve the quality. As a result,
automatically classifying reviews according to different requirements evolves
as a popular research topic and is essential in our daily life. In this paper,
we focused on reviews of hot TV series in China and successfully trained
generic classifiers based on eight predefined categories. The experimental
results showed promising performance and effectiveness of its generalization to
different TV series.


title:
The sub-$k$-domination number of a graph with applications to
  $k$-domination

abstract:
  In this paper we introduce and study a new graph invariant derived from the
degree sequence of a graph $G$, called the sub-$k$-domination number and
denoted $sub_k(G)$. We show that $sub_k(G)$ is a computationally efficient
sharp lower bound on the $k$-domination number of $G$, and improves on several
known lower bounds. We also characterize the sub-$k$-domination numbers of
several families of graphs, provide structural results on sub-$k$-domination,
and explore properties of graphs which are $sub_k(G)$-critical with respect to
addition and deletion of vertices and edges.


title:
Policy Optimization for Content Push via Energy Harvesting Small Cells
  in Heterogeneous Networks

abstract:
  Motivated by the rapid development of energy harvesting technology and
content-aware communication in access networks, this paper considers the push
mechanism design in small-cell base stations (SBSs) powered by renewable
energy. A user request can be satisfied by either push or unicast from the SBS.
If the SBS cannot handle the request, the user is blocked by the SBS and is
served by the macro-cell BS (MBS) instead, which typically consumes more
energy. We aim to minimize the ratio of user requests blocked by the SBS. With
finite battery capacity, Markov decision process based problem is formulated,
and the optimal policy is found by dynamic programming (DP). Two
threshold-based policies are proposed: the push-only threshold-based (POTB)
policy and the energy-efficient threshold-based (EETB) policy, and the
closed-form blocking probabilities with infinite battery capacity are derived.
Numerical results show that the proposed policies outperform the conventional
non-push policy if the content popularity changes slowly or the content request
generating rate is high, and can achieve the performance of the greedy optimal
threshold-based (GOTB) policy. In addition, the performance gap between the
threshold-based policies and the DP optimal policy is small when the energy
arrival rate is low or the request generating rate is high.


title: Reproducing kernel method for PDE constrained optimization

abstract:
  This paper presents reproducing kernel Hilbert spaces method to obtain the
numerical solution for partial differential equation constrained optimization
problem.


title: Valley Hall Effect and Nonlocal Transport in Strained Graphene

abstract:
  Graphene subject to high levels of shear strain leads to strong
pseudo-magnetic fields resulting in the emergence of Landau levels. Here we
show that, with modest levels of strain, graphene can also sustain a classical
valley hall effect (VHE) that can be detected in nonlocal transport
measurements. We provide a theory of the strain-induced VHE starting from the
quantum Boltzmann equation. This allows us to show that, averaging over
short-range impurity configurations destroys quantum coherence between valleys,
leaving the elastic scattering time and inter-valley scattering rate as the
only parameters characterizing the transport theory. Using the theory, we
compute the nonlocal resistance of a Hall bar device in the diffusive regime.
Our theory is also relevant for the study of moderate strain effects in the
(nonlocal) transport properties of other two-dimensional materials and van der
Walls heterostructures.


title:
Superconductivity and magnetism in Iron Sulfides Intercalated by Metal
  Hydroxides

abstract:
  Inspired by naturally occurring sulfide minerals, we present a new family of
iron-based superconductors. A metastable form of FeS known as the mineral
mackinawite forms two-dimensional sheets that can be readily intercalated by
various cationic guest species. Under hydrothermal conditions using alkali
metal hydroxides, we prepare three different cation and metal
hydroxide-intercalated FeS phases including (Li$_{1-x}$Fe$_x$OH)FeS,
[(Na$_{1-x}$Fe$_x$)(OH)$_2$]FeS, and K$_x$Fe$_{2-y}$S$_2$. Upon successful
intercalation of the FeS layer, the superconducting critical temperature $T_c$
of mackinawite is enhanced from 5 K to 8 K for the
(Li$_{1-x}$Fe$_x$OH)$^{\delta+}$ intercalate. Layered heterostructures of
[(Na$_{1-x}$Fe$_x$)(OH)$_2$]FeS resemble the natural mineral tochilinite, which
contains an iron square lattice interleaved with a hexagonal hydroxide lattice.
Whilst heterostructured [(Na$_{1-x}$Fe$_x$)(OH)$_2$]FeS displays long-range
magnetic ordering near 15 K, K$_x$Fe$_{2-y}$S$_2$ displays short range
antiferromagnetism.


title:
Strong maximum principle for mean curvature operators on subriemannian
  manifolds

abstract:
  We study the strong maximum principle for horizontal (p-) mean curvature
operator and p-(sub)laplacian operator on subriemannian manifolds including, in
particular, Heisenberg groups and Heisenberg cylinders. Under a certain
Hormander type condition on vector fields, we show the strong maximum principle
holds in higher dimensions for two cases: (a) the touching point is
nonsingular; (b) the touching point is an isolated singular point for one of
comparison functions. For a background subriemannian manifold with local
symmetry of isometric translations, we have the strong maximum principle for
associated graphs which include, among others, intrinsic graphs with constant
horizontal (p-) mean curvature. As applications, we show a rigidity result of
horizontal (p-) minimal hypersurfaces in any higher dimensional Heisenberg
cylinder and a pseudo-halfspace theorem for any Heisenberg group.


title:
Combining observational and experimental data to find heterogeneous
  treatment effects

abstract:
  Every design choice will have different effects on different units. However
traditional A/B tests are often underpowered to identify these heterogeneous
effects. This is especially true when the set of unit-level attributes is
high-dimensional and our priors are weak about which particular covariates are
important. However, there are often observational data sets available that are
orders of magnitude larger. We propose a method to combine these two data
sources to estimate heterogeneous treatment effects. First, we use
observational time series data to estimate a mapping from covariates to
unit-level effects. These estimates are likely biased but under some conditions
the bias preserves unit-level relative rank orderings. If these conditions
hold, we only need sufficient experimental data to identify a monotonic,
one-dimensional transformation from observationally predicted treatment effects
to real treatment effects. This reduces power demands greatly and makes the
detection of heterogeneous effects much easier. As an application, we show how
our method can be used to improve Facebook page recommendations.


title: Noise, diffusion, and hyperuniformity

abstract:
  We consider driven many-particle models which have a phase transition between
an active and an absorbing phase. Like previously studied models, we have
particle conservation, but here we introduce an additional symmetry - when two
particles interact, we give them stochastic kicks which conserve center of
mass. We find that the density fluctuations in the active phase decay in the
fastest manner possible for a disordered isotropic system, and we present
arguments that the large scale fluctuations are determined by a competition
between a noise term which generates fluctuations, and a deterministic term
which reduces them. Our results may be relevant to shear experiments and may
further the understanding of hyperuniformity which occurs at the critical
point.


title: EW baryogenesis via DM

abstract:
  We discuss the impact of a swifter cosmological expansion induced by modified
cosmological history of the universe on scenarios realising electroweak
baryogenesis. We detail the possible experimental bounds one can place on such
cosmological modification and show how the detection capabilities of particle
models are modified within these bounds. On the particle physics side we focus
on the Standard Model supplemented by a dimension six operator which directly
modifies the Higgs potential. We show that due to the cosmological
modification, electroweak baryogenesis in this model can be realized, with the
modification of the triple Higgs coupling below HL-LHC sensitivity.


title: PNP: Fast Path Ensemble Method for Movie Design

abstract:
  How can we design a product or movie that will attract, for example, the
interest of Pennsylvania adolescents or liberal newspaper critics? What should
be the genre of that movie and who should be in the cast? In this work, we seek
to identify how we can design new movies with features tailored to a specific
user population. We formulate the movie design as an optimization problem over
the inference of user-feature scores and selection of the features that
maximize the number of attracted users. Our approach, PNP, is based on a
heterogeneous, tripartite graph of users, movies and features (e.g., actors,
directors, genres), where users rate movies and features contribute to movies.
We learn the preferences by leveraging user similarities defined through
different types of relations, and show that our method outperforms
state-of-the-art approaches, including matrix factorization and other
heterogeneous graph-based analysis. We evaluate PNP on publicly available
real-world data and show that it is highly scalable and effectively provides
movie designs oriented towards different groups of users, including men, women,
and adolescents.


title:
Accretion of a relativistic, collisionless kinetic gas into a
  Schwarzschild black hole

abstract:
  We provide a systematic study for the accretion of a collisionless,
relativistic kinetic gas into a nonrotating black hole. To this end, we first
solve the relativistic Liouville equation on a Schwarzschild background
spacetime. The most general solution for the distribution function is given in
terms of appropriate symplectic coordinates on the cotangent bundle, and the
associated observables, including the particle current density and stress
energy-momentum tensor, are determined. Next, we explore the case where the
flow is steady-state and spherically symmetric. Assuming that in the asymptotic
region the gas is described by an equilibrium distribution function, we
determine the relevant parameters of the accretion flow as a function of the
particle density and the temperature of the gas at infinity. In particular, we
find that in the low temperature limit the tangential pressure at the horizon
is about an order of magnitude larger than the radial one, showing explicitly
that a collisionless gas, despite exerting kinetic pressure, behaves very
differently than an isotropic perfect fluid, and providing a partial
explanation for the known fact that the accretion rate is much lower than in
the hydrodynamic case of Bondi-Michel accretion. Finally, we establish the
asymptotic stability of the steady-state spherical flows by proving pointwise
convergence results which show that a large class of (possibly nonstationary
and nonspherical) initial conditions for the distribution function lead to
solutions of the Liouville equation which relax in time to a steady-state,
spherically symmetric configuration.


title:
On the $C^{1,1}$ regularity of geodesics in the space of K\"ahler
  metrics

abstract:
  We prove that any two Kahler potentials on a compact Kahler manifold can be
connected by a geodesic segment of C^{1,1} regularity. This follows from an a
priori interior real Hessian bound for solutions of the nondegenerate complex
Monge-Ampere equation, which is independent of a positive lower bound for the
right hand side.


title:
Crossover from weakly to strongly correlated regions in the
  two-dimensional Hubbard model -- Off-diagonal wave function Monte Carlo
  studies of Hubbard model II --

abstract:
  The ground state of the two-dimensional (2D) Hubbard model is investigated by
adopting improved wave functions that take into account intersite electron
correlation beyond the Gutzwiller ansatz. The ground-state energy is lowered
considerably, giving the best estimate of the ground-state energy for the 2D
Hubbard model. There is a crossover from weakly to strongly correlated regions
as the on-site Coulomb interaction $U$ increases. The antiferromagnetic
correlation induced by $U$ is reduced for hole doping when $U$ is large, being
greater than the bandwidth, thus increasing the kinetic energy gain. The spin
and charge fluctuations are induced in the strongly correlated region. These
antiferromagnetic and kinetic charge fluctuations induce electron pairings,
which would result in high-temperature superconductivity.


title: Sums of Uncertainty: Refinements Go Gradual

abstract:
  A long-standing shortcoming of statically typed functional languages is that
type checking does not rule out pattern-matching failures (run-time match
exceptions). Refinement types distinguish different values of datatypes; if a
program annotated with refinements passes type checking, pattern-matching
failures become impossible. Unfortunately, refinement is a monolithic property
of a type, exacerbating the difficulty of adding refinement types to nontrivial
programs.
  Gradual typing has explored how to incrementally move between static typing
and dynamic typing. We develop a type system of gradual sums that combines
refinement with imprecision. Then, we develop a bidirectional version of the
type system, which rules out excessive imprecision, and give a type-directed
translation to a target language with explicit casts. We prove that the static
sublanguage cannot have match failures, that a well-typed program remains
well-typed if its type annotations are made less precise, and that making
annotations less precise causes target programs to fail later. Several of these
results correspond to criteria for gradual typing given by Siek et al. (2015).


title:
Entanglement enhancement through multi-rail noise reduction for
  continuous-variable measurement-based quantum information processing

abstract:
  We study theoretically the teleportation of controlled-phase (CZ) gate
through measurement-based quantum information processing for
continuous-variable systems. We examine the degree of entanglement in the
output modes of the teleported CZ-gate for two classes of resource states: the
canonical cluster states that are constructed via direct implementations of
two-mode squeezing operations, and the linear-optical version of cluster states
which are built from linear-optical networks of beam splitters and phase
shifters. In order to reduce the excess noise arising from finite-squeezed
resource states, teleportation through resource states with different
multi-rail designs will be considered and the enhancement of entanglement in
the teleported CZ-gates will be analyzed. For multi-rail cluster with an
arbitrary number of rails, we obtain analytical expressions for the
entanglement in the output modes and analyze in detail the results for both
classes of resource states. At the same time, we also show that for uniformly
squeezed clusters the multi-rail noise reduction can be optimized when the
excess noise is allocated uniformly to the rails. To facilitate the analysis,
we develop a trick with manipulations of quadrature operators that can reveal
rather efficiently the measurement sequence and corrective operations needed
for the measurement-based gate teleportation, which will also be explained in
detail.


title:
Spin polarization and color superconductivity in the Nambu--Jona-Lasinio
  model at finite temperature

abstract:
  We investigate the possible existence of spin polarization and color
superconductivity in the Nambu--Jona-Lasinio model with a tensor-type
interaction at finite density and temperature. The thermodynamic potential is
calculated by the functional integral method. Numerical results indicate that
at low temperature and quark chemical potential the chiral condensed phase
exists, and at intermediate chemical potential the color superconducting phase
appears. In addition, depending on the magnitude of the tensor coupling, at
large chemical potential and low temperature, a color superconducting phase and
a spin polarized phase may coexist while at intermediate temperatures only the
spin polarized phase occurs.


title:
Landau level evolution driven by band hybridization in mirror symmetry
  broken ABA-stacked trilayer graphene

abstract:
  Layer stacking and crystal lattice symmetry play important roles in the band
structure and the Landau levels of multilayer graphene. ABA-stacked trilayer
graphene possesses mirror-symmetry-protected monolayer-like and bilayer-like
band structures. Broken mirror symmetry by a perpendicular electric field
therefore induces hybridization between these bands and various quantum Hall
phases emerge. We experimentally explore the evolution of Landau levels in
ABA-stacked trilayer graphene under electric field. We observe a variety of
valley and orbital dependent Landau level evolutions. These evolutions are
qualitatively well explained by considering the hybridization between multiple
Landau levels possessing close Landau level indices and the hybridization
between every third Landau level orbitals due to the trigonal warping effect.
These observations are consistent with numerical calculations. The combination
of experimental and numerical analysis thus reveals the entire picture of
Landau level evolutions decomposed into the monolayer- and bilayer-like band
contributions in ABA-stacked trilayer graphene.


title: Mean pion multiplicities in Ar+Sc collisions

abstract:
  Preliminary results for mean negatively charged pion multiplicities $\langle
\pi^- \rangle$ using the $h^-$ method are presented for central Ar+Sc
collisions at 13, 19, 30, 40, 75 and 150\textit{A} GeV/c beam momentum. The
data were recorded by the NA61/SHINE detector at the CERN SPS. Starting with
rapidity distributions ${dn}/{dy}$ the procedure of obtaining total
multiplicities is presented. The mean number of wounded nucleons $\langle
W\rangle$ extracted from the Glissando MC model is used to calculate the ratio
$\langle \pi^- \rangle/\langle W\rangle.$ The results are compared to those
from other experiments and their dependence on colliding systems and collision
energy is discussed.


title: The elliptic gluon GTMD inside a large nucleus

abstract:
  We evaluate the elliptic gluon Generalized Transverse Momentum
Dependent(GTMD) distribution inside a large nucleus using the
McLerran-Venugopalan model. We further show that this gluon distribution can be
probed through the angular correlation in virtual photon quasi-elastic
scattering on a nucleus.


title: Spatial non-adiabatic passage using geometric phases

abstract:
  Quantum technologies based on adiabatic techniques can be highly effective,
but often at the cost of being very slow. Here we introduce a set of
experimentally realistic, non-adiabatic protocols for spatial state
preparation, which yield the same fidelity as their adiabatic counterparts, but
on fast timescales. In particular, we consider a charged particle in a system
of three tunnel-coupled quantum wells, where the presence of a magnetic field
can induce a geometric phase during the tunnelling processes. We show that this
leads to the appearance of complex tunnelling amplitudes and allows for the
implementation of spatial non-adiabatic passage. We demonstrate the ability of
such a system to transport a particle between two different wells and to
generate a delocalised superposition between the three traps with high fidelity
in short times.


title:
Effect of Mg-Al insertion on magnetotransport properties in epitaxial
  Fe/sputter-deposited $MgAl_{2}O_{4}$/Fe(001) magnetic tunnel junctions

abstract:
  We investigated the effect of a Mg-Al layer insertion at the bottom interface
of epitaxial Fe/$MgAl_{2}O_{4}$/Fe(001) magnetic tunnel junctions (MTJs) on
their spin-dependent transport properties. The tunnel magnetoresistance (TMR)
ratio and differential conductance spectra for the parallel magnetic
configuration exhibited clear dependence on the inserted Mg-Al thickness. A
slight Mg-Al insertion (thickness < 0.1 nm) was effective for obtaining a large
TMR ratio above 200% at room temperature and observing a distinct local minimum
structure in conductance spectra. In contrast, thicker Mg-Al (> 0.2 nm) induced
a reduction of TMR ratios and featureless conductance spectra, indicating a
degradation of the bottom-Fe/$MgAl_{2}O_{4}$ interface. Therefore, a minimal
Mg-Al insertion was found to be effective to maximize the TMR ratio for a
sputtered $MgAl_{2}O_{4}$-based MTJ.


title: A Graph-Theoretic Approach to Multitasking

abstract:
  A key feature of neural network architectures is their ability to support the
simultaneous interaction among large numbers of units in the learning and
processing of representations. However, how the richness of such interactions
trades off against the ability of a network to simultaneously carry out
multiple independent processes -- a salient limitation in many domains of human
cognition -- remains largely unexplored. In this paper we use a graph-theoretic
analysis of network architecture to address this question, where tasks are
represented as edges in a bipartite graph $G=(A \cup B, E)$. We define a new
measure of multitasking capacity of such networks, based on the assumptions
that tasks that \emph{need} to be multitasked rely on independent resources,
i.e., form a matching, and that tasks \emph{can} be multitasked without
interference if they form an induced matching. Our main result is an inherent
tradeoff between the multitasking capacity and the average degree of the
network that holds \emph{regardless of the network architecture}. These results
are also extended to networks of depth greater than $2$. On the positive side,
we demonstrate that networks that are random-like (e.g., locally sparse) can
have desirable multitasking properties. Our results shed light into the
parallel-processing limitations of neural systems and provide insights that may
be useful for the analysis and design of parallel architectures.


title: Divide and Conquer Networks

abstract:
  We consider the learning of algorithmic tasks by mere observation of
input-output pairs. Rather than studying this as a black-box discrete
regression problem with no assumption whatsoever on the input-output mapping,
we concentrate on tasks that are amenable to the principle of divide and
conquer, and study what are its implications in terms of learning. This
principle creates a powerful inductive bias that we leverage with neural
architectures that are defined recursively and dynamically, by learning two
scale-invariant atomic operations: how to split a given input into smaller
sets, and how to merge two partially solved tasks into a larger partial
solution. Our model can be trained in weakly supervised environments, namely by
just observing input-output pairs, and in even weaker environments, using a
non-differentiable reward signal. Moreover, thanks to the dynamic aspect of our
architecture, we can incorporate the computational complexity as a
regularization term that can be optimized by backpropagation. We demonstrate
the flexibility and efficiency of the Divide-and-Conquer Network on several
combinatorial and geometric tasks: convex hull, clustering, knapsack and
euclidean TSP. Thanks to the dynamic programming nature of our model, we show
significant improvements in terms of generalization error and computational
complexity.


title:
Rapid Satellite-to-Site Visibility Determination Based on Self-Adaptive
  Interpolation Technique

abstract:
  Rapid satellite-to-site visibility determination is of great significance to
coverage analysis of satellite constellations as well as onboard mission
planning of autonomous spacecraft. This paper presents a novel self-adaptive
Hermite interpolation technique for rapid satellite-to-site visibility
determination. Piecewise cubic curves are utilized to approximate the waveform
of the visibility function versus time. The fourth-order derivative is used to
control the approximation error and to optimize the time step for
interpolation. The rise and set times are analytically obtained from the roots
of cubic polynomials. To further increase the computational speed, an interval
shrinking strategy is adopted via investigating the geometric relationship
between the ground viewing cone and the orbit trajectory. Simulation results
show a 98% decrease in computation time over the brute force method. The method
is suitable for all orbital types and analytical orbit propagators.


title:
Examining posterior propriety in the Bayesian analysis of
  capture-recapture models

abstract:
  There lies a latent danger in utilizing some known mathematical results in
ecology. Some results do not apply to the problem at hand. We identify one such
trend. Based on a couple of theorems in mathematical statistics, Link (2013)
cautions ecologists about the inappropriateness of using the discrete uniform
prior in their analysis under certain conditions and instead recommends the
routine use of the scale prior during analysis. This recommendation is been
absorbed immediately and widely among ecologists. In this study, we consider
the two fundamental capture-recapture models used widely in ecology, $M_0$ and
$M_h$, and derive conditions for posterior propriety by examining the behavior
of the right tail of the posterior distributions of animal population size $N$
in a Bayesian analysis. We demonstrate that both these likelihoods are far more
efficient than the ones considered in Link (2013). We argue that no
particularly prescriptive approach should be adopted by ecologists in regard to
choosing priors of the fear of posterior impropriety. Instead, we recommend the
efficient construction of likelihoods for the problem and data on hand,
choosing priors based existing knowledge of a parameter of interest and
encourage examining posterior propriety by asymptotic arguments as demonstrated
in this study.


title:
Influence of defects on the effective electrical conductivity of a
  monolayer produced by random sequential adsorption of linear $k$-mers onto a
  square lattice

abstract:
  The effect of defects on the behavior of electrical conductivity in a
monolayer produced by the random sequential adsorption of linear $k$-mers
(particles occupying $k$ adjacent sites) onto a square lattice is studied by
means of a Monte Carlo simulation. The $k$-mers are deposited on the substrate
until a jamming state is reached, i.e. a state where no one additional particle
can be placed because the presented voids are too small or of inappropriate
shapes. The presence of defects in the lattice (impurities) and of defects in
the $k$-mers with concentrations of $d_l$ and $d_k$, respectively, is assumed.
The defects in the lattice are distributed randomly before deposition and these
lattice sites are forbidden for the deposition of $k$-mers. The defects on the
$k$-mers are distributed randomly. The sites filled with $k$-mers have high
electrical conductivity whereas the empty sites, and the sites filled by either
types of defect have a low electrical conductivity, i.e., a high-contrast is
assumed. We examined isotropic (both the possible orientations of a particle
are equiprobable) and anisotropic (all particles are aligned along one given
direction, $y$) deposition. To calculate the effective electrical conductivity,
the monolayer was presented as a random resistor network (RRN) and the
Frank--Lobb algorithm was used. The effects of the concentrations of defects
$d_l$ and $d_k$ on the electrical conductivity for the values of $k = 2^n$,
where $n =1,2,\dots, 5$, were studied. Increase of both the $d_l$ and $d_k$
parameters values resulted in decreases in the value of $\sigma$ and the
suppression of percolation. Moreover, for anisotropic deposition the electrical
conductivity along the $y$ direction was noticeably larger than in the
perpendicular direction, $x$. Phase diagrams in the ($d_l, d_k$)-plane for
different values of $k$ were obtained.


title: Modified Bonnor-Ebert spheres with ambipolar diffusion heating

abstract:
  Magnetic fluctuations through the molecular cloud cores can produce ambipolar
diffusion (AD) heating, which consequently can produce temperature gradients
through the core. The aim of this paper is to investigate the effects of these
produced temperature gradients on the radius and mass of the non-isothermal
modified Bonnor-Ebert spheres (MBES). Here, we use the parameter $\kappa$ to
represent the magnetic fluctuations through the molecular cloud cores. This
parameter introduces the change of magnetic filed strength in the length-scale.
The results show that increasing of $\kappa$ leads to an increase of the radius
and mass of MBES. The most important result is existence of the gravitationally
stable high-mass prestellar cores at the low-density molecular medium with
great magnetic fluctuations.


title: Measurement of hyperfine structure in the $ \rm D_1 $ line of Rb

abstract:
  We report a precise measurement of hyperfine constants in the $\rm{D_1} $
line ($ \rm {5\,P_{1/2}} $ state) of the two stable isotopes of Rb. The
motivation for the work is to try and resolve discrepant values that exists in
the literature. We use a technique that is different from other methods---one
where the laser is not locked to a particular transition but scanned around it.
This is advantageous because it overcomes frequency shifts due to servo-loop
errors and other sources of noise in the experiment. The values in the two
isotopes are: $ A = 120.510(26) $ MHz in $\rm {^{85}Rb}$, and $ A = 408.340(19)
$ MHz in $\rm {^{87}Rb}$. These values are at variance with earlier values
reported from our lab, but consistent with other published measurements.


title:
Simple error bounds for the QBD approximation of a special class of two
  dimensional reflecting random walks

abstract:
  This paper considers the QBD approximation of a special class of
two-dimensional reflecting random walks (2D-RRWs). A typical example of the
2D-RRWs is a two-node Jackson network with cooperative servers. The main
contribution of this paper is to provide simple upper bounds for the relative
absolute difference between the time-averaged functionals of the original
2D-RRW and its QBD approximation.


title: Real-time Algorithm for Self-Reflective Model Predictive Control

abstract:
  This paper is about a real-time model predictive control (MPC) algorithm for
a particular class of model based controllers, whose objective consists of a
nominal tracking objective and an additional learning objective. Here, the
construction of the learning term is based on economic optimal experiment
design criteria. It is added to the MPC objective in order to excite the system
from time-to-time on purpose in order to improve the accuracy of the state and
parameter estimates in the presence of incomplete or noise affected
measurements. A particular focus of this paper is on so-called self-reflective
model predictive control schemes, which have the property that the additional
learning term can be interpreted as the expected loss of optimality of the
controller in the presence of random measurement errors. The main contribution
of this paper is a formulation-tailored algorithm, which exploits the
particular structure of self-reflective MPC problems in order to speed-up the
online computation. It is shown that, in contrast to generic state-of-the-art
optimal control problem solvers, the proposed algorithm can solve the
self-reflective optimization problems with reasonable additional computational
effort and in real-time. The advantages of the proposed real-time scheme are
illustrated by applying the algorithm to a nonlinear process control problem in
the presence of measurement errors and process noise.