title: Far-UV Emission Properties of FR1 Radio Galaxies

abstract:
  The power mechanism and accretion geometry for low-power FR1 radio galaxies
is poorly understood in comparison to Seyfert galaxies and QSOs. In this paper
we use the diagnostic power of the Lya recombination line observed using the
Cosmic Origins Spectrograph (COS) aboard the Hubble Space Telescope (HST) to
investigate the accretion flows in three well-known, nearby FR1s: M87, NGC4696,
and HydraA. The Ly$\alpha$ emission line's luminosity, velocity structure and
the limited knowledge of its spatial extent provided by COS are used to assess
conditions within a few parsecs of the super-massive black hole (SMBH) in these
radio-mode AGN. We observe strong Ly$\alpha$ emission in all three objects with
similar total luminosity to that seen in BL Lacertae objects. M87 shows a
complicated emission line profile in Lya which varies spatially across the COS
aperture and possibly temporally over several epochs of observation. In both
NGC 4696 and M87, the Ly$\alpha$ luminosities $\sim 10^{40}$ ergs/s are closely
consistent with the observed strength of the ionizing continuum in Case B
recombination theory and with the assumption of near unity covering factor. It
is possible that the Ly$\alpha$ emitting clouds are ionized largely by beamed
radiation associated with the jets. Long-slit UV spectroscopy can be used to
test this hypothesis. Hydra A and the several BL Lac objects studied in this
and previous papers have Lya luminosities larger than M87 but their
extrapolated, non-thermal continua are so luminous that they over-predict the
observed strength of Ly$\alpha$, a clear indicator of relativistic beaming in
our direction. Given their substantial space density ($\sim 4\times10^{-3}
Mpc^{-3}$) the unbeamed Lyman continuum radiation of FR1s may make a
substantial minority contribution (~10%) to the local UV background if all FR1s
are similar to M87 in ionizing flux level.


title: Squeezed vacua in loop quantum gravity

abstract:
  We introduce squeezed vacua in loop quantum gravity, a new overcomplete basis
of states that contain prescribable correlations between geometric operators.
We study the behavior of long-range correlations and discuss the relevance of
these states for the reconstruction of a semiclassical spacetime from loop
quantum gravity.


title:
Thermal and Quantum Phase Transitions in Atom-Field Systems: a
  Microcanonical Analysis

abstract:
  The thermodynamical properties of a generalized Dicke model are calculated
and related with the critical properties of its energy spectrum, namely the
quantum phase transitions (QPT) and excited state quantum phase transitions
(ESQPT). The thermal properties are calculated both in the canonical and the
microcanonical ensembles. The latter deduction allows for an explicit
description of the relation between thermal and energy spectrum properties.
While in an isolated system the subspaces with different pseudo spin are
disconnected, and the whole energy spectrum is accesible, in the thermal
ensamble the situation is radically different. The multiplicity of the lowest
energy states for each pseudo spin completely dominates the thermal behavior,
making the set of degenerate states with the smallest pseudo spin at a given
energy the only ones playing a role in the thermal properties, making the
positive energy states thermally inaccesible. Their quantum phase transitions,
from a normal to a superradiant phase, are closely associated with the thermal
transition. The other critical phenomena, the ESQPTs occurring at excited
energies, have no manifestation in the thermodynamics, although their effects
could be seen in finite sizes corrections. A new superradiant phase is found,
which only exists in the generalized model, and can be relevant in finite size
systems.


title: Are Maxwell's equations Lorentz-covariant?

abstract:
  The statement that Maxwell's electrodynamics in vacuum is already covariant
under Lorentz transformations is commonplace in the literature. We analyse the
actual meaning of that statement and demonstrate that Maxwell's equations are
perfectly fit to be Lorentz-covariant; they become Lorentz-covariant if we
construct to be so, by postulating certain transformation properties of field
functions. In Aristotelian terms, the covariance is a plain potentiality, but
not necessarily entelechy.


title:
Option Discovery in Hierarchical Reinforcement Learning using
  Spatio-Temporal Clustering

abstract:
  This paper introduces an automated skill acquisition framework in
reinforcement learning which involves identifying a hierarchical description of
the given task in terms of abstract states and extended actions between
abstract states. Identifying such structures present in the task provides ways
to simplify and speed up reinforcement learning algorithms. These structures
also help to generalize such algorithms over multiple tasks without relearning
policies from scratch. We use ideas from dynamical systems to find metastable
regions in the state space and associate them with abstract states. The
spectral clustering algorithm PCCA+ is used to identify suitable abstractions
aligned to the underlying structure. Skills are defined in terms of the
sequence of actions that lead to transitions between such abstract states. The
connectivity information from PCCA+ is used to generate these skills or
options. These skills are independent of the learning task and can be
efficiently reused across a variety of tasks defined over the same model. This
approach works well even without the exact model of the environment by using
sample trajectories to construct an approximate estimate. We also present our
approach to scaling the skill acquisition framework to complex tasks with large
state spaces for which we perform state aggregation using the representation
learned from an action conditional video prediction network and use the skill
acquisition framework on the aggregated state space.


title:
Data Constrained Coronal Mass Ejections in A Global Magnetohydrodynamics
  Model

abstract:
  We present a first-principles-based coronal mass ejection (CME) model
suitable for both scientific and operational purposes by combining a global
magnetohydrodynamics (MHD) solar wind model with a flux rope-driven CME model.
Realistic CME events are simulated self-consistently with high fidelity and
forecasting capability by constraining initial flux rope parameters with
observational data from GONG, SOHO/LASCO, and STEREO/COR. We automate this
process so that minimum manual intervention is required in specifying the CME
initial state. With the newly developed data-driven Eruptive Event Generator
Gibson-Low (EEGGL), we present a method to derive Gibson-Low (GL) flux rope
parameters through a handful of observational quantities so that the modeled
CMEs can propagate with the desired CME speeds near the Sun. A test result with
CMEs launched with different Carrington rotation magnetograms are shown. Our
study shows a promising result for using the first-principles-based MHD global
model as a forecasting tool, which is capable of predicting the CME direction
of propagation, arrival time, and ICME magnetic field at 1 AU (see companion
paper by Jin et al. 2016b).


title:
The Geometry of the Wigner Caustic and a Decomposition of a Curve Into
  Parallel Arcs

abstract:
  In this paper we study global properties of the Wigner caustic of
parameterized closed planar curves. We find new results on its geometry and
singular points. In particular, we consider the Wigner caustic of rosettes,
i.e. regular closed parameterized curves with non-vanishing curvature.
  We present a decomposition of a curve into parallel arcs to describe smooth
branches of the Wigner caustic. By this construction we can find the number of
smooth branches, the rotation number, the number of inflexion points and the
parity of the number of cusp singularities of each branch. We also study the
global properties of the Wigner caustic on shell (the branch of the Wigner
caustic connecting two inflexion points of a curve). We apply our results to
whorls - the important object to study the dynamics of a quantum particle in
the optical lattice potential.


title: Yelp Dataset Challenge: Review Rating Prediction

abstract:
  Review websites, such as TripAdvisor and Yelp, allow users to post online
reviews for various businesses, products and services, and have been recently
shown to have a significant influence on consumer shopping behaviour. An online
review typically consists of free-form text and a star rating out of 5. The
problem of predicting a user's star rating for a product, given the user's text
review for that product, is called Review Rating Prediction and has lately
become a popular, albeit hard, problem in machine learning. In this paper, we
treat Review Rating Prediction as a multi-class classification problem, and
build sixteen different prediction models by combining four feature extraction
methods, (i) unigrams, (ii) bigrams, (iii) trigrams and (iv) Latent Semantic
Indexing, with four machine learning algorithms, (i) logistic regression, (ii)
Naive Bayes classification, (iii) perceptrons, and (iv) linear Support Vector
Classification. We analyse the performance of each of these sixteen models to
come up with the best model for predicting the ratings from reviews. We use the
dataset provided by Yelp for training and testing the models.


title: Bounds on the rate of disjunctive codes (in Russian)

abstract:
  A binary code is called a superimposed cover-free $(s,\ell)$-code if the code
is identified by the incidence matrix of a family of finite sets in which no
intersection of $\ell$ sets is covered by the union of $s$ others. A binary
code is called a superimposed list-decoding $s_L$-code if the code is
identified by the incidence matrix of a family of finite sets in which the
union of any $s$ sets can cover not more than $L-1$ other sets of the family.
For $L=\ell=1$, both of the definitions coincide and the corresponding binary
code is called a superimposed $s$-code. Our aim is to obtain new lower and
upper bounds on the rate of the given codes. In particular, we derive lower
bounds on the rates of a superimposed cover-free $(s,\ell)$-code and
list-decoding $s_L$-code based on the ensemble of constant weight binary codes.
Also, we establish an upper bound on the rate of superimposed list-decoding
$s_L$-code.


title: Searching for molecular outflows in Hyper-Luminous Infrared Galaxies

abstract:
  We present constraints on the molecular outflows in a sample of five
Hyper-Luminous Infrared Galaxies using Herschel observations of the OH doublet
at 119 {\mu}m. We have detected the OH doublet in three cases: one purely in
emission and two purely in absorption. The observed emission profile has a
significant blueshifted wing suggesting the possibility of tracing an outflow.
Out of the two absorption profiles, one seems to be consistent with the
systemic velocity while the other clearly indicates the presence of a molecular
outflow whose maximum velocity is about ~1500 km/s. Our analysis shows that
this system is in general agreement with previous results on Ultra-luminous
Infrared Galaxies and QSOs, whose outflow velocities do not seem to correlate
with stellar masses or starburst luminosities (star formation rates). Instead
the galaxy outflow likely arises from an embedded AGN.


title: Dynamic Frame skip Deep Q Network

abstract:
  Deep Reinforcement Learning methods have achieved state of the art
performance in learning control policies for the games in the Atari 2600
domain. One of the important parameters in the Arcade Learning Environment
(ALE) is the frame skip rate. It decides the granularity at which agents can
control game play. A frame skip value of $k$ allows the agent to repeat a
selected action $k$ number of times. The current state of the art architectures
like Deep Q-Network (DQN) and Dueling Network Architectures (DuDQN) consist of
a framework with a static frame skip rate, where the action output from the
network is repeated for a fixed number of frames regardless of the current
state. In this paper, we propose a new architecture, Dynamic Frame skip Deep
Q-Network (DFDQN) which makes the frame skip rate a dynamic learnable
parameter. This allows us to choose the number of times an action is to be
repeated based on the current state. We show empirically that such a setting
improves the performance on relatively harder games like Seaquest.


title: LHC Future Prospects of the 750 GeV Resonance

abstract:
  A quantitative discussion on the future prospects of the 750 GeV resonance at
the LHC experiment is given using a simple effective field theory analysis. The
relative size of two effective operators relevant to diphoton decays can be
probed by ratios of diboson signals in a robust way. We obtain the future
sensitivities of $Z\gamma $, $ZZ$ and $WW$ resonance searches at the high
luminosity LHC, rescaling from the current sensitivities at $\sqrt{s}=13$ TeV.
Then, we show that a large fraction of parameter space in the effective field
theory will be covered with 300 fb$^{-1}$ and almost the whole parameter space
will be tested with 3000 fb$^{-1}$. This discussion is independent of
production processes, other decay modes and total decay width.


title: Establishment and stability of the latent HIV-1 DNA reservoir

abstract:
  HIV-1 infection currently cannot be cured because the virus persists as
integrated proviral DNA in long-lived cells despite years of suppressive
antiretroviral therapy (ART). To characterize establishment, turnover, and
evolution of viral DNA reservoirs we deep-sequenced the p17gag region of the
HIV-1 genome from samples obtained after 3-18 years of suppressive ART from 10
patients. For each of these patients, whole genome deep-sequencing data of
HIV-1 RNA populations before onset of ART were available from 6-12 longitudinal
plasma samples spanning 5-8 years of untreated infection. This enabled a
detailed analysis of the dynamics and origin of proviral DNA during ART. A
median of 14% (range 0-42%) of the p17gag DNA sequences were overtly defective
due to G-to-A hypermutation. The remaining sequences were remarkably similar to
previously observed RNA sequences and showed no evidence of evolution over many
years of suppressive ART. Most sequences from the DNA reservoirs were very
similar to viruses actively replicating in plasma (RNA sequences) shortly
before start of ART. The results do not support persistent HIV-1 replication as
a mechanism to maintain the HIV-1 reservoir during suppressive therapy. Rather,
the data indicate that viral DNA variants are turning over as long as patients
are untreated and that suppressive ART halts this turnover.


title: Deep Action Sequence Learning for Causal Shape Transformation

abstract:
  Deep learning became the method of choice in recent year for solving a wide
variety of predictive analytics tasks. For sequence prediction, recurrent
neural networks (RNN) are often the go-to architecture for exploiting
sequential information where the output is dependent on previous computation.
However, the dependencies of the computation lie in the latent domain which may
not be suitable for certain applications involving the prediction of a
step-wise transformation sequence that is dependent on the previous computation
only in the visible domain. We propose that a hybrid architecture of
convolution neural networks (CNN) and stacked autoencoders (SAE) is sufficient
to learn a sequence of actions that nonlinearly transforms an input shape or
distribution into a target shape or distribution with the same support. While
such a framework can be useful in a variety of problems such as robotic path
planning, sequential decision-making in games, and identifying material
processing pathways to achieve desired microstructures, the application of the
framework is exemplified by the control of fluid deformations in a microfluidic
channel by deliberately placing a sequence of pillars. Learning of a multistep
topological transform has significant implications for rapid advances in
material science and biomedical applications.


title: Audio Features Affected by Music Expressiveness

abstract:
  Within a Music Information Retrieval perspective, the goal of the study
presented here is to investigate the impact on sound features of the musician's
affective intention, namely when trying to intentionally convey emotional
contents via expressiveness. A preliminary experiment has been performed
involving $10$ tuba players. The recordings have been analysed by extracting a
variety of features, which have been subsequently evaluated by combining both
classic and machine learning statistical techniques. Results are reported and
discussed.


title: Training A Quantum Optimizer

abstract:
  We study a variant of the quantum approximate optimization algorithm [ E.
Farhi, J. Goldstone, and S. Gutmann, arXiv:1411.4028] with slightly different
parametrization and different objective: rather than looking for a state which
approximately solves an optimization problem, our goal is to find a quantum
algorithm that, given an instance of MAX-2-SAT, will produce a state with high
overlap with the optimal state. Using a machine learning approach, we chose a
"training set" of instances and optimized the parameters to produce large
overlap for the training set. We then tested these optimized parameters on a
larger instance set. As a training set, we used a subset of the hard instances
studied by E. Crosson, E. Farhi, C. Yen-Yu Lin, H.-H. Lin, and P. Shor (CFLLS)
[arXiv:1401.7320]. When tested on the full set, the parameters that we find
produce significantly larger overlap than the optimized annealing times of
CFLLS. Testing on other random instances from $20$ to $28$ bits continues to
show improvement over annealing, with the improvement being most notable on the
hardest instances. Further tests on instances of MAX-3-SAT also showed
improvement on the hardest instances. This algorithm may be a possible
application for near-term quantum computers with limited coherence times.


title:
Identification of conserved moieties in metabolic networks by graph
  theoretical analysis of atom transition networks

abstract:
  Conserved moieties are groups of atoms that remain intact in all reactions of
a metabolic network. Identification of conserved moieties gives insight into
the structure and function of metabolic networks and facilitates metabolic
modelling. All moiety conservation relations can be represented as nonnegative
integer vectors in the left null space of the stoichiometric matrix
corresponding to a biochemical network. Algorithms exist to compute such
vectors based only on reaction stoichiometry but their computational complexity
has limited their application to relatively small metabolic networks. Moreover,
the vectors returned by existing algorithms do not, in general, represent
conservation of a specific moiety with a defined atomic structure. Here, we
show that identification of conserved moieties requires data on reaction atom
mappings in addition to stoichiometry. We present a novel method to identify
conserved moieties in metabolic networks by graph theoretical analysis of their
underlying atom transition networks. Our method returns the exact group of
atoms belonging to each conserved moiety as well as the corresponding vector in
the left null space of the stoichiometric matrix. It can be implemented as a
pipeline of polynomial time algorithms. Our implementation completes in under
five minutes on a metabolic network with more than 4,000 mass balanced
reactions. The scalability of the method enables extension of existing
applications for moiety conservation relations to genome-scale metabolic
networks. We also give examples of new applications made possible by
elucidating the atomic structure of conserved moieties.


title:
Stability of standing waves for logarithmic Schr\"odinger equation with
  attractive delta potential

abstract:
  We consider the one-dimensional logarithmic Schr\"odinger equation with a
delta potential. Global well-posedness is verified for the Cauchy problem in
H1(R) and in an appropriate Orlicz space. In the attractive case, we prove
orbital stability of the ground states via variational approach.


title:
Binary Black Holes, Gas Sloshing, and Cold Fronts in the X-ray Halo
  Hosting 4C+37.11

abstract:
  We analyzed deep $Chandra$ ACIS-I exposures of the cluster-scale X-ray halo
surrounding the radio source 4C+37.11. This remarkable system hosts the closest
resolved pair of super-massive black hole and an exceptionally luminous
elliptical galaxy, the likely product of a series of past mergers. We
characterize the halo with $r_{500} = 0.95$ Mpc, $M_{500} = (2.5 \pm 0.2)
\times 10^{14} \ M_{\rm{\odot}}$, $ kT = 4.6\pm 0.2$ keV, and a gas mass of
$M_{\rm g,500} = (2.2 \pm 0.1) \times 10^{13} M_\odot$. The gas mass fraction
within $r_{500}$ is $f_{\rm g} = 0.09 \pm 0.01$. The entropy profile shows
large non-gravitational heating in the central regions. We see several surface
brightness jumps, associated with substantial temperature and density changes,
but approximate pressure equilibrium, implying that these are sloshing
structures driven by a recent merger. A residual intensity image shows core
spiral structure closely matching that seen for the Perseus cluster, although
at $z=0.055$ the spiral pattern is less distinct. We infer the most recent
merger occurred $1-2$ Gyr ago and that the event that brought the two observed
super-massive black holes to the system core is even older. Under that
interpretation, this black hole binary pair has, unusually, remained at
pc-scale separation for more than 2 Gyr.


title: The Global History of Reionisation

abstract:
  Using a Bayesian framework, we quantify what current observations imply about
the history of the epoch of reionisation (EoR). We use a popular,
three-parameter EoR model, flexible enough to accommodate a wide range of
physically-plausible reionisation histories. We study the impact of various EoR
observations: (i) the optical depth to the CMB measured by Planck 2016; (ii)
the dark fraction in the Lyman $\alpha$ and $\beta$ forests; (iii) the redshift
evolution of galactic Ly$\alpha$ emission (so-called "Ly$\alpha$ fraction");
(iv) the clustering of Ly$\alpha$ emitters; (v) the IGM damping wing imprint in
the spectrum of QSO ULASJ1120+0641; (vi) and the patchy kinetic
Sunyaev-Zel'dovich signal. Combined, (i) and (ii) already place interesting
constraints on the reionisation history, with the epochs corresponding to an
average neutral fraction of (75, 50, 25) per cent, constrained at 1$\sigma$ to
$z= (9.21\substack{+1.22 -1.15}, 8.14\substack{+1.08 -1.00},
7.26\substack{+1.13 -0.96})$. Folding-in more model-dependent EoR observations
[(iii--vi)], strengthens these constraints by tens of per cent, at the cost of
a decrease in the likelihood of the best-fit model, driven mostly by (iii). The
tightest constraints come from (v). Unfortunately, no current observational set
is sufficient to break degeneracies and constrain the astrophysical EoR
parameters. However, model-dependent priors on the EoR parameters themselves
can be used to set tight limits by excluding regions of parameter space with
strong degeneracies. Motivated by recent observations of $z\sim7$ faint, lensed
galaxies, we show how a conservative upper limit on the virial temperature of
haloes which host reionising galaxies can constrain the escape fraction of
ionising photons to $f_{\rm esc} = 0.14\substack{+0.26 -0.09}$


title:
Thermodynamic properties of rod-like chains: entropic sampling
  simulations

abstract:
  In this work we apply entropic sampling simulations to a three-state model
which has exact solutions in the microcanonical and grand-canonical ensembles.
We consider $N$ chains placed on an unidimensional lattice, such that each site
may assume one of three-states: empty (state 1), with a single molecule
energetically null (state 2), and with a single molecule with energy
$\varepsilon$ (state 3). Each molecule, which we will treat here as dimers,
consists of two monomers connected one to each other by a rod. The
thermodynamic properties, such as internal energy, densities of dimers and
specific heat were obtained as functions of temperature where the analytic
results in the micro-canonical and grand-canonical ensembles were successfully
confirmed by the entropic sampling simulations.


title:
The First High-Phase Observations of a KBO: New Horizons Imaging of
  (15810) 1994 JR1 from the Kuiper Belt

abstract:
  NASA's New Horizons spacecraft observed (15810) 1994 JR$_1$, a 3:2 resonant
Kupier Belt Object (KBO), using the LOng Range Reconnaissance Imager (LORRI) on
November 2, 2015 from a distance of 1.85 AU, and again on April 7, 2016 from a
distance of 0.71 AU. These were the first close observations of any KBO other
than Pluto. Combining ground-based and Hubble Space Telecope (HST) observations
at small phase angles and the LORRI observations at higher phase angles, we
produced the first disk-integrated solar phase curve of a typical KBO from
$\alpha$=0.6-58$^\circ$. Observations at these geometries, attainable only from
a spacecraft in the outer Solar System, constrain surface properties such as
macroscopic roughness and the single particle phase function. 1994 JR$_1$ has a
rough surface with a 37$\pm$5$^\circ$ mean topographic slope angle and has a
relatively rapid rotation period of 5.47$\pm$0.33 hours. 1994 JR$_1$ is
currently 2.7 AU from Pluto; our astrometric points enable high-precision orbit
determination and integrations which show that it comes this close to Pluto
every 2.4 million years (10$^4$ heliocentric orbits), causing Pluto to perturb
1994 JR$_1$. During the November spacecraft observation, the KBO was
simultaneously observed using HST in two colors, confirming its very red
spectral slope. These observations have laid the groundwork for numerous
potential future distant KBO observations in the New Horizons-Kuiper Belt
Extended Mission.


title: The case of equality in H\"older's inequality for matrices and operators

abstract:
  Let $p>1$ and $1/p+1/q=1$. Consider H\"older's inequality $$ \|ab^*\|_1\le
\|a\|_p\|b\|_q $$ for the $p$-norms of some trace ($a,b$ are matrices, compact
operators, elements of a finite $C^*$-algebra or a semi-finite von Neumann
algebra). This note contains a simple proof (based on the case $p=2$) of the
fact that equality holds iff $|a|^p=\lambda |b|^q$ for some $\lambda\ge 0$.


title: Frictional sliding without geometrical reflection symmetry

abstract:
  The dynamics of frictional interfaces play an important role in many physical
systems spanning a broad range of scales. It is well-known that frictional
interfaces separating two dissimilar materials couple interfacial slip and
normal stress variations, a coupling that has major implications on their
stability, failure mechanism and rupture directionality. In contrast,
interfaces separating identical materials are traditionally assumed not to
feature such a coupling due to symmetry considerations. We show, combining
theory and experiments, that interfaces which separate bodies made of
macroscopically identical materials, but lack geometrical reflection symmetry,
generically feature such a coupling. We discuss two applications of this novel
feature. First, we show that it accounts for a distinct, and previously
unexplained, experimentally observed weakening effect in frictional cracks.
Second, we demonstrate that it can destabilize frictional sliding which is
otherwise stable. The emerging framework is expected to find applications in a
broad range of systems.


title: High Resolution Compressed Sensing Radar using Difference Set Codes

abstract:
  In this paper, we consider compressive sensing (CS)-based recovery of delays
and Doppler frequencies of targets in high resolution radars. We propose a
novel sub-Nyquist sampling method in the Fourier domain based on difference
sets (DS), called DS-sampling, to create dictionaries with highly incoherent
atoms. The coherence of the dictionary reaches the Welch minimum bound if the
DS-sampling is employed. This property let us to implement sub-Nyquist high
resolution radars with minimum number of samples. We also develop a low
complexity recovery method, based on structured CS and propose a new waveform,
called difference set--frequency coded modulated (DS-FCM) waveform, to boost
the recovery performance of the sub-Nyquist radar in noisy environments. The
proposed method solves some of the common problems in many CS-based radars and
overcome disadvantages of the conventional Nyquist processing, i.e. matched
filtering in high resolution radar systems. The proposed method allows us to
design sub-Nyquist radars, which require less than 2% of Nyquist samples and
recover targets without resolution degradation in comparison to the
conventional Nyquist processing.


title: Chern classes and Characteristic Cycles of Determinantal Varieties

abstract:
  Let $K$ be an algebraically closed field of characteristic $0$. For $m\geq
n$, we define $\tau_{m,n,k}$ to be the set of $m\times n$ matrices over $K$
with kernel dimension $\geq k$. This is a projective subvariety of
$\bbP^{mn-1}$, and is called the (generic) determinantal variety. In most cases
$\tau_{m,n,k}$ is singular with singular locus $\tau_{m,n,k+1}$. In this paper
we give explicit formulas computing the Chern-Mather class ($c_M$) and the
Chern-Schwartz-MacPherson class ($c_{SM}$) of $\tau_{m,n,k}$, as classes in the
projective space. We also obtain formulas for the conormal cycles and the
characteristic cycles of these varieties, and for their generic Euclidean
Distance degree. Further, when $K=\bbC$, we prove that the characteristic cycle
of the intersection cohomology sheaf of a determinantal variety agrees with its
conormal cycle (and hence is irreducible).
  Our formulas are based on calculations of degrees of certain Chern classes of
the universal bundles over the Grassmannian. For some small values of $m,n,k$,
we use Macaulay2 to exhibit examples of the Chern-Mather classes, the
Chern-Schwartz-MacPherson classes and the classes of characteristic cycles of
$\tau_{m,n,k}$.
  On the basis of explicit computations in low dimensions, we formulate
conjectures concerning the effectivity of the classes and the vanishing of
specific terms in the Chern-Schwartz-MacPherson classes of the largest strata
$\tau_{m,n,k}\smallsetminus \tau_{m,n,k+1}$.
  The irreducibility of the characteristic cycle of the intersection cohomology
sheaf follows from the Kashiwara-Dubson's microlocal index theorem, a study of
the `Tjurina transform' of $\tau_{m,n,k}$, and the recent computation of the
local Euler obstruction of $\tau_{m,n,k}$ .


title:
An Improved Method of Lifetime Measurement of Nuclei in Radioactive
  Decay Chain

abstract:
  We present an improved statistical method for calculation of mean lifetime of
nuclei in a decay chain with uncertain relation between mother and daughter
nuclei. The method is based on formation of time distribution of intervals
between mother and daughter nuclei, without trying to set the exact
mother-daughter nuclei relationship. If there is a coincidence of mother and
daughter nuclei decays, sum of these distributions has flat term on which an
exponential term is superimposed. Parameters of this exponential function allow
lifetime of daughter nucleus to be extracted. The method is tested on Monte
Carlo simulation data.


title: A Harris process to model stochastic volatility

abstract:
  We present a tractable non-independent increment process which provides a
high modeling flexibility. The process lies on an extension of the so-called
Harris chains to continuous time being stationary and Feller. We exhibit
constructions, properties, and inference methods for the process. Afterwards,
we use the process to propose a stochastic volatility model with an arbitrary
but fixed invariant distribution, which can be tailored to fit different
applied scenarios. We study the model performance through simulation while
illustrating its use in practice with empirical work. The model proves to be an
interesting competitor to a number of short-range stochastic volatility models.


title:
A comprehensive scenario of the thermodynamic anomalies of water using
  the TIP4P/2005 model

abstract:
  The striking behavior of water has deserved it to be referred to as an
"anomalous" liquid. The water anomalies are greatly amplified in metastable
(supercooled/stretched) regions. This makes difficult a complete experimental
description since, beyond certain limits, the metastable phase necessarily
transforms into the stable one. Theoretical interpretation of the water
anomalies could then be based on simulation results of well validated water
models. But the analysis of the simulations has not yet reached a consensus. In
particular, one of the most popular theoretical scenarios -involving the
existence of a liquid-liquid critical point (LLCP)- is disputed by several
authors. In this work we propose to use a number of exact thermodynamic
relations which can be tested in a region of the phase diagram outside the LLCP
thus avoiding the problems associated to the coexistence region. The central
property connected to other water anomalies is the locus of temperatures at
which the density along isobars attain a maximum (TMD line) or a minimum (TmD),
computed via simulations for a successful water model, TIP4P/2005. Next, we
have evaluated the vapor-liquid spinodal in the region of large negative
pressures. The shape of these curves and their connection to the extrema of
response functions (isothermal compressibility and heat capacity at constant
pressure) may help to elucidate the validity of the theoretical proposals. In
this way we are able to present for the first time a comprehensive scenario of
the thermodynamic water anomalies for TIP4P/2005 and their relation to the
vapor-liquid spinodal. The overall picture shows a remarkable similarity with
the corresponding one for the ST2 water model, for which the existence of a
LLCP has been demonstrated in recent years. It also provides a hint as to where
the long-sought for extrema in response functions might become accessible to
experiments.


title:
Random Access Preamble Design and Detection for 3GPP Narrowband IoT
  Systems

abstract:
  Narrowband internet of things (NB-IoT) is an emerging cellular technology
that will provide improved coverage for massive number of low-throughput
low-cost devices with low device power consumption in delay-tolerant
applications. A new single tone signal with frequency hopping has been designed
for NB-IoT physical random access channel (NPRACH). In this letter we describe
this new NPRACH design and explain in detail the design rationale. We further
propose possible receiver algorithms for NPRACH detection and time-of-arrival
estimation. Simulation results on NPRACH performance including detection rate,
false alarm rate, and time-of-arrival estimation accuracy are presented to shed
light on the overall potential of NB-IoT systems.


title: Residues in group completions and the Cech cohomology of BG

abstract:
  Let $G$ be a connected affine algebraic group over $\mathbb{C}$, $G \to X$ be
an open immersion of $G$-varieties, $Z = X-G$ and $i: Z \to X$ be the
inclusion. Let $\alpha \in H^*(G,\mathbb{C})$ be primitive. We give a method to
compute the image of $\alpha$ in $H^*(Z, i^!\mathbb{C}_X)$, using a lift of
$\alpha$ along the first edge map of the \v{C}ech spectral sequence for
$H^*(BG, \mathbb{C})$. We apply it to the wonderful compactification of a
centerless semisimple group $G$.


title: Splitting theorems for Poisson and related structures

abstract:
  According to the Weinstein splitting theorem, any Poisson manifold is
locally, near any given point, a product of a symplectic manifold with another
Poisson manifold whose Poisson structure vanishes at the point. Similar
splitting results are known e.g. for Lie algebroids, Dirac structures and
generalized complex structures. In this paper, we develop a novel approach
towards these results that leads to various generalizations, including their
equivariant versions as well as their formulations in new contexts.


title:
On the stabilizers of finite sets of numbers in the R. Thompson group
  $F$

abstract:
  We study subgroups $H_U$ of the R. Thompson group $F$ which are stabilizers
of finite sets $U$ of numbers in the interval $(0,1)$. We describe the
algebraic structure of $H_U$ and prove that the stabilizer $H_U$ is finitely
generated if and only if $U$ consists of rational numbers. We also show that
such subgroups are isomorphic surprisingly often. In particular, we prove that
if finite sets $U\subset [0,1]$ and $V\subset [0,1]$ consist of rational
numbers which are not finite binary fractions, and $|U|=|V|$, then the
stabilizers of $U$ and $V$ are isomorphic. In fact these subgroups are
conjugate inside a subgroup $\bar F<\Homeo([0,1])$ which is the completion of
$F$ with respect to what we call the Hamming metric on $F$. Moreover the
conjugator can be found in a certain subgroup $\F < \bar F$ which consists of
possibly infinite tree-diagrams with finitely many infinite branches. We also
show that the group $\F$ is non-amenable.


title:
Globally Conservative, Hybrid Self-Adjoint Angular Flux and
  Least-Squares Method Compatible with Void

abstract:
  In this paper, we derive a method for the second-order form of the transport
equation that is both globally conservative and compatible with voids, using
Continuous Finite Element Methods (CFEM). The main idea is to use the
Least-Squares (LS) form of the transport equation in the void regions and the
Self-Adjoint Angular Flux (SAAF) form elsewhere. While the SAAF formulation is
globally conservative, the LS formulation need a correction in void. The price
to pay for this fix is the loss of symmetry of the bilinear form. We first
derive this Conservative LS (CLS) formulation in void. Second we combine the
SAAF and CLS forms and end up with an hybrid SAAF-CLS method, having the
desired properties. We show that extending the theory to near-void regions is a
minor complication and can be done without affecting the global conservation of
the scheme. Being angular discretization agnostic, this method can be applied
to both discrete ordinates (SN) and spherical harmonics (PN) methods. However,
since a globally conservative and void compatible second-order form already
exists for SN (Wang et al. 2014), but is believed to be new for PN, we focus
most of our attention on that latter angular discretization. We implement and
test our method in Rattlesnake within the Multiphysics Object Oriented
Simulation Environment (MOOSE) framework. Results comparing it to other methods
are presented.


title: Crystallization kinetics of binary colloidal monolayers

abstract:
  Experiments and simulations are used to study the kinetics of crystal growth
in a mixture of magnetic and nonmagnetic particles suspended in ferrofluid. The
growth process is quantified using both a bond order parameter and a mean
domain size parameter. The largest single crystals obtained in experiments
consist of approximately 1000 particles and form if the area fraction is held
between 65-70% and the field strength is kept in the range of 8.5-10.5 Oe.
Simulations indicate that much larger single crystals containing as many as
5000 particles can be obtained in impurity-free conditions within a few hours.
If our simulations are modified to include impurity concentrations as small as
1-2%, then the results agree quantitatively with the experiments. These
findings provide an important step toward developing strategies for growing
single crystals that are large enough to enable follow-on investigations across
many subdisciplines in condensed matter physics.


title:
The Orbit of the L dwarf + T dwarf Spectral Binary SDSS
  J080531.84+481233.0

abstract:
  [abridged] We report four years of radial velocity monitoring observations of
SDSS J080531.84+481233.0 that reveal significant and periodic variability,
confirming the binary nature of the source. We infer an orbital period of
2.02$\pm$0.03 yr, a semi-major axis of 0.76$^{+0.05}_{-0.06}$ AU, and an
eccentricity of 0.46$\pm$0.05, consistent with the amplitude of astrometric
variability and prior attempts to resolve the system. Folding in constraints
based on the spectral types of the components (L4$\pm$0.7 and T5.5$\pm$1.1),
corresponding effective temperatures, and brown dwarf evolutionary models, we
further constrain the orbital inclination of this system to be nearly edge-on
(90$^o\pm$19$^o$), and deduce a large system mass ratio (M$_2$/M$_1$ =
0.86$^{+0.10}_{-0.12}$), substellar components (M$_1$ =
0.057$^{+0.016}_{-0.014}$ M$_{\odot}$, M$_2$ = 0.048$^{+0.008}_{-0.010}$
M$_{\odot}$), and a relatively old system age (minimum age =
4.0$^{+1.9}_{-1.2}$ Gyr). The measured projected rotational velocity of the
primary ($v\sin{i}$ = 34.1$\pm$0.7 km/s) implies that this inactive source is a
rapid rotator (period $\lesssim$ 3 hr) and a viable system for testing
spin-orbit alignment in very-low-mass multiples. The combination of
well-determined component atmospheric properties and masses near and/or below
the hydrogen minimum mass make SDSS J0805+4812AB an important system for future
tests of brown dwarf evolutionary models.


title: The Information Flow Problem on Clock Networks

abstract:
  The information flow problem on a network asks whether $r$ senders, $v_1,v_2,
\ldots ,v_r$ can each send messages to $r$ corresponding receivers $v_{n+1},
\ldots ,v_{n+r}$ via intermediate nodes $v_{r+1}, \ldots ,v_n$. For a given
finite $R \subset \mathbb{Z}^+$, the clock network $N_n(R)$ has edge $v_iv_k$
if and only if $k>r$ and $k-i \in R$. We show that the information flow problem
on $N_n(\{1,2, \ldots ,r\})$ can be solved for all $n \geq r$. We also show
that for any finite $R$ such that $\gcd(R)=1$ and $r = \max(R)$, we show that
the information flow problem can be solved on $N_n(R)$ for all $n \geq 3r^3$.


title:
Far Infrared Variability of Sagittarius A*: 25.5 Hours of Monitoring
  with $Herschel$

abstract:
  Variable emission from Sgr~A*, the luminous counterpart to the super-massive
black hole at the center of our Galaxy, arises from the innermost portions of
the accretion flow. Better characterization of the variability is important for
constraining models of the low-luminosity accretion mode powering Sgr~A*, and
could further our ability to use variable emission as a probe of the strong
gravitational potential in the vicinity of the
$4\times10^{6}\mathrm{M}_{\odot}$ black hole. We use the \textit{Herschel}
Spectral and Photometric Imaging Receiver (SPIRE) to monitor Sgr~A* at
wavelengths that are difficult or impossible to observe from the ground. We
find highly significant variations at 0.25, 0.35, and 0.5 mm, with temporal
structure that is highly correlated across these wavelengths. While the
variations correspond to $<$1% changes in the total intensity in the
\textit{Herschel} beam containing Sgr~A*, comparison to independent,
simultaneous observations at 0.85 mm strongly supports the reality of the
variations. The lowest point in the light curves, $\sim$0.5 Jy below the
time-averaged flux density, places a lower bound on the emission of Sgr~A* at
0.25 mm, the first such constraint on the THz portion of the SED. The
variability on few hour timescales in the SPIRE light curves is similar to that
seen in historical 1.3 mm data, where the longest time series is available, but
the distribution of variations in the sub-mm do not show a tail of
large-amplitude variations seen at 1.3 mm. Simultaneous X-ray photometry from
XMM-Newton shows no significant variation within our observing period, which
may explain the lack of very large variations if X-ray and submillimeter flares
are correlated.


title:
Laser-induced asymmetric faceting and growth of nano-protrusion on a
  tungsten tip

abstract:
  Irradiation of a sharp tungsten tip by a femtosecond laser and exposed to a
strong DC electric field led to gradual and reproducible surface modifications.
By a combination of field emission microscopy and scanning electron microscopy,
we observed asymmetric surface faceting with sub-ten nanometer high steps. The
presence of well pronounced faceted features mainly on the laser-exposed side
implies that the surface modification was driven by a laser-induced transient
temperature rise -- on a scale of a couple of picoseconds -- in the tungsten
tip apex. Moreover, we identified the formation of a nano-tip a few nanometers
high located at one of the corners of a faceted plateau. The results of
simulations emulating the experimental conditions, are consistent with the
experimental observations. The presented conditions can be used as a new method
to fabricate nano-tips of few nm height, which can be used in coherent electron
pulses generation. Besides the direct practical application, the results also
provide insight into the microscopic mechanisms of light-matter interaction.
The apparent growth mechanism of the features may also help to explain the
origin of enhanced electron field emission, which leads to vacuum arcs, in high
electric-field devices such as radio-frequency particle accelerators.


title:
Two-fold quasi-alternating links, Khovanov homology and instanton
  homology

abstract:
  We introduce a class of links strictly containing quasi-alternating links for
which mod 2 reduced Khovanov homology is always thin. We compute the framed
instanton homology for double branched covers of such links. Aligning certain
dotted markings on a link with bundle data over the branched cover, we also
provide many computations of framed instanton homology in the presence of a
non-trivial real 3-plane bundle. We discuss evidence for a spectral sequence
from the twisted Khovanov homology of a link with mod 2 coefficients to the
framed instanton homology of the double branched cover. We also discuss the
relevant mod 4 gradings.


title: Learning Deep Representations of Fine-grained Visual Descriptions

abstract:
  State-of-the-art methods for zero-shot visual recognition formulate learning
as a joint embedding problem of images and side information. In these
formulations the current best complement to visual features are attributes:
manually encoded vectors describing shared characteristics among categories.
Despite good performance, attributes have limitations: (1) finer-grained
recognition requires commensurately more attributes, and (2) attributes do not
provide a natural language interface. We propose to overcome these limitations
by training neural language models from scratch; i.e. without pre-training and
only consuming words and characters. Our proposed models train end-to-end to
align with the fine-grained and category-specific content of images. Natural
language provides a flexible and compact way of encoding only the salient
visual aspects for distinguishing categories. By training on raw text, our
model can do inference on raw text as well, providing humans a familiar mode
both for annotation and retrieval. Our model achieves strong performance on
zero-shot text-based image retrieval and significantly outperforms the
attribute-based state-of-the-art for zero-shot classification on the Caltech
UCSD Birds 200-2011 dataset.


title: Generative Adversarial Text to Image Synthesis

abstract:
  Automatic synthesis of realistic images from text would be interesting and
useful, but current AI systems are still far from this goal. However, in recent
years generic and powerful recurrent neural network architectures have been
developed to learn discriminative text feature representations. Meanwhile, deep
convolutional generative adversarial networks (GANs) have begun to generate
highly compelling images of specific categories, such as faces, album covers,
and room interiors. In this work, we develop a novel deep architecture and GAN
formulation to effectively bridge these advances in text and image model- ing,
translating visual concepts from characters to pixels. We demonstrate the
capability of our model to generate plausible images of birds and flowers from
detailed text descriptions.


title:
New Insights into Rental Housing Markets across the United States: Web
  Scraping and Analyzing Craigslist Rental Listings

abstract:
  Current sources of data on rental housing - such as the census or commercial
databases that focus on large apartment complexes - do not reflect recent
market activity or the full scope of the U.S. rental market. To address this
gap, we collected, cleaned, analyzed, mapped, and visualized 11 million
Craigslist rental housing listings. The data reveal fine-grained spatial and
temporal patterns within and across metropolitan housing markets in the U.S. We
find some metropolitan areas have only single-digit percentages of listings
below fair market rent. Nontraditional sources of volunteered geographic
information offer planners real-time, local-scale estimates of rent and housing
characteristics currently lacking in alternative sources, such as census data.


title:
On growth of systole along congruence coverings of Hilbert modular
  varieties

abstract:
  We study how the systole of principal congruence coverings of a Hilbert
modular variety grows when the degree of the covering goes to infinity. We
prove that given a Hilbert modular variety $M$ of real dimension $2n$, the
sequence of principal congruence coverings $M_{I}$ eventually satisfies
$$sys\pi_{1}(M_{I})\geq \frac{4}{3\sqrt{n}}\log(vol(M_{I}))-c,$$ where $c$ is a
constant independent of $M_{I}$.


title: Memory effect from supernova neutrino shells

abstract:
  When a supernova explodes, most of its energy is released in a shell of
relativistic neutirnos which changes the surrounding geometry. We calculate the
potentially observable responses to such a change in both pulsar scintillation
and conventional interferometers. In both cases, the responses are permanent
changes due to such a transient event. This is by-definition a memory effect.
In addition to the transverse component in the usual gravitational memory
(Christodolou effect) effect, it also has a longitudinal component. Furthermore
it is different from the Christodolou effect as the transverse component of
this memory effect also has a term that grows with time.


title: Whittaker functions on metaplectic covers of GL(r)

abstract:
  This paper establishes a combinatorial link between different approaches to
constructing Whittaker functions on a metaplectic group over a non-archimedean
local field. We prove a metaplectic analogue of Tokuyama's Theorem and give a
crystal description of polynomials related to Iwahori-Whittaker functions. The
proof relies on formulas of metaplectic Demazure and Demazure-Lusztig
operators, proved previously in joint work with Gautam Chinta and Paul E.
Gunnells.


title:
Pricing the Woman Card: Gender Politics between Hillary Clinton and
  Donald Trump

abstract:
  In this paper, we propose a data-driven method to measure the impact of the
'woman card' exchange between Hillary Clinton and Donald Trump. Building from a
unique dataset of the two candidates' Twitter followers, we first examine the
transition dynamics of the two candidates' Twitter followers one week before
the exchange and one week after. Then we train a convolutional neural network
to classify the gender of the followers and unfollowers, and study how women in
particular are reacting to the 'woman card' exchange. Our study suggests that
the 'woman card' comment has made women more likely to follow Hillary Clinton,
less likely to unfollow her and that it has apparently not affected the gender
composition of Trump followers.


title: Statistical mechanics of ontology based annotations

abstract:
  We present a statistical mechanical theory of the process of annotating an
object with terms selected from an ontology. The term selection process is
formulated as an ideal lattice gas model, but in a highly structured
inhomogeneous field. The model enables us to explain patterns recently observed
in real-world annotation data sets, in terms of the underlying graph structure
of the ontology. By relating the external field strengths to the information
content of each node in the ontology graph, the statistical mechanical model
also allows us to propose a number of practical metrics for assessing the
quality of both the ontology, and the annotations that arise from its use.
Using the statistical mechanical formalism we also study an ensemble of
ontologies of differing size and complexity; an analysis not readily performed
using real data alone. Focusing on regular tree ontology graphs we uncover a
rich set of scaling laws describing the growth in the optimal ontology size as
the number of objects being annotated increases. In doing so we provide a
further possible measure for assessment of ontologies.


title: Sudden jumps and plateaus in the quench dynamics of a Bloch state

abstract:
  We take a one-dimensional tight binding chain with periodic boundary
condition and put a particle in an arbitrary Bloch state, then quench it by
suddenly changing the potential of an arbitrary site. In the ensuing time
evolution, the probability density of the wave function at an arbitrary site
\emph{jumps indefinitely between plateaus}. This phenomenon adds to a former
one in which the survival probability of the particle in the initial Bloch
state shows \emph{cusps} periodically, which was found in the same scenario
[Zhang J. M. and Yang H.-T., EPL, \textbf{114} (2016) 60001]. The plateaus
support the scattering wave picture of the quench dynamics of the Bloch state.
Underlying the cusps and jumps is the exactly solvable, nonanalytic dynamics of
a Luttinger-like model, based on which, the locations of the jumps and the
heights of the plateaus are accurately predicted.


title: CSA++: Fast Pattern Search for Large Alphabets

abstract:
  Indexed pattern search in text has been studied for many decades. For small
alphabets, the FM-Index provides unmatched performance, in terms of both space
required and search speed. For large alphabets -- for example, when the tokens
are words -- the situation is more complex, and FM-Index representations are
compact, but potentially slow. In this paper we apply recent innovations from
the field of inverted indexing and document retrieval to compressed pattern
search, including for alphabets into the millions. Commencing with the
practical compressed suffix array structure developed by Sadakane, we show that
the Elias-Fano code-based approach to document indexing can be adapted to
provide new tradeoff options in indexed pattern search, and offers
significantly faster pattern processing compared to previous implementations,
as well as reduced space requirements. We report a detailed experimental
evaluation that demonstrates the relative advantages of the new approach, using
the standard Pizza&Chili methodology and files, as well as applied use-cases
derived from large-scale data compression, and from natural language
processing. For large alphabets, the new structure gives rise to space
requirements that are close to those of the most highly-compressed FM-Index
variants, in conjunction with unparalleled search throughput rates.


title: The ABC's of affine Grassmannians and Hall-Littlewood polynomials

abstract:
  We give a new description of the Pieri rule for k-Schur functions using the
Bruhat order on the affine type-A Weyl group. In doing so, we prove a new
combinatorial formula for representatives of the Schubert classes for the
cohomology of affine Grassmannians. We show how new combinatorics involved in
our formulas gives the Kostka-Foulkes polynomials and discuss how this can be
applied to study the transition matrices between Hall-Littlewood and k-Schur
functions.


title:
Seasonal and Lunar month periods observed in natural neutron flux at
  high altitude

abstract:
  Air radon concentration measurement is useful for research on geophysical
effects, but it is strongly sensitive to site geology and many geophysical and
microclimatic processes such as wind, ventilation, air humidity and so on that
induce very big fluctuations on the concentration of radon in air. On the
contrary, monitoring the radon concentration in soil by measuring the thermal
neutron flux reduces environmental effects. In this paper we report some
experimental results on the natural thermal neutron flux as well as the
concentration of air radon and its variations at 4300 m a.s.l. These results
were obtained with unshielded thermal neutron scintillation detectors
(en-detectors) and radon monitors located inside the ARGO-YBJ experimental
hall. The correlation of these variations with the lunar month and 1-year
period is undoubtedly confirmed. A method for earthquakes prediction provided
by a global net of the en-detectors is currently under study.


title:
Superfluid density and microwave conductivity of FeSe superconductor:
  ultra-long-lived quasiparticles and extended s-wave energy gap

abstract:
  FeSe is an iron-based superconductor of immense current interest due to the
large enhancements of Tc that occur when it is pressurized or grown as a single
layer on an insulating substrate. Here we report precision measurements of its
superconducting electrodynamics, at frequencies of 202 and 658 MHz and at
temperatures down to 0.1 K. The quasiparticle conductivity reveals a rapid
collapse in scattering on entering the superconducting state that is strongly
reminiscent of unconventional superconductors such as cuprates, organics and
the heavy fermion material CeCoIn5. At the lowest temperatures the
quasiparticle mean free path exceeds 50 micron, a record for a compound
superconductor. From the superfluid response we confirm the importance of
multiband superconductivity and reveal strong evidence for a finite energy-gap
minimum.


title:
Superoutburst of CR Bootis: Estimation of Mass Ratio of a typical AM CVn
  star by Stage A Superhumps

abstract:
  We report on two superoutbursts of the AM CVn-type object CR Boo in 2014
April--March and 2015 May--June. A precursor outburst acompanied both of these
superoutbursts. During the rising branch of the main superoutburst in 2014, we
detected growing superhumps (stage A superhumps) whose period was
$0.017669(24)$ d. Assuming that this period reflects the dynamical precession
rate at the radius of the 3:1 resonance, we could estimate the mass ratio
($q=M_2/M_1$) of 0.101(4) by using the stage A superhump period and the orbital
one of 0.0170290(6) d. This mass ratio is consistent with that expected by the
theoretical evolutionary model of AM CVn-type objects. The detection of
precursor outbursts and stage A superhumps is the second case in AM CVn-type
objects. There are two interpretations of the outbursts of AM CVn-type objects.
One is a dwarf nova (DN) outbursts analogy, which is caused by thermal and
tidal instabilities. Another is the VY Scl-type variation, which is caused by
the variation of the mass-transfer rate of the secondary. This detection of the
superhump variations strongly suggests the former interpretation.


title:
Chiral anomaly and giant magnetochiral anisotropy in noncentrosymmetric
  Weyl semimetals

abstract:
  We theoretically propose that giant magnetochiral anisotropy is achieved in
Weyl semimetals in noncentrosymmetric crystals as a consequence of the chiral
anomaly. The magnetochiral anisotropy is the nonlinearity of the resistivity
$\rho$ that depends on the current $\boldsymbol{I}$ and the magnetic field
$\boldsymbol{B}$ as $\rho=\rho_0 (1 + \gamma \boldsymbol{I} \cdot
\boldsymbol{B})$, and can be applied to rectifier devices controlled by
$\boldsymbol{B}$. We derive the formula for the coefficient $\gamma$ in
noncentrosymmetric Weyl semimetals. The obtained formula for $\gamma$ shows
that the magnetochiral anisotropy is strongly enhanced when the chemical
potential is tuned to Weyl points, and that noncentrosymmetric Weyl semimetals
such as TaAs can exhibit much larger magnetochiral anisotropy than that
observed in other materials so far.


title:
Smoothing for the Zakharov & Klein-Gordon-Schr\"{o}dinger Systems on
  Euclidean Spaces

abstract:
  This paper studies the regularity of solutions to the Zakharov and
Klein-Gordon-Schr\"{o}dinger systems at low regularity levels. The main result
is that the nonlinear part of the solution flow falls in a smoother space than
the initial data. This relies on a new bilinear $X^{s,b}$ estimate, which is
proved using delicate dyadic and angular decompositions of the frequency
domain. Such smoothing estimates have a number of implications for the
long-term dynamics of the system. In this work, we give a simplified proof of
the existence of global attractors for the Klein-Gordon-Schr\"{o}dinger flow in
the energy space for dimensions $d = 2,3$. Secondly, we use smoothing in
conjunction with a high-low decomposition to show global well-posedness of the
Klein-Gordon-Schr\"{o}dinger evolution on $\mathbb{R}^4$ below the energy space
for sufficiently small initial data.


title: Are Facial Attributes Adversarially Robust?

abstract:
  Facial attributes are emerging soft biometrics that have the potential to
reject non-matches, for example, based on mismatching gender. To be usable in
stand-alone systems, facial attributes must be extracted from images
automatically and reliably. In this paper, we propose a simple yet effective
solution for automatic facial attribute extraction by training a deep
convolutional neural network (DCNN) for each facial attribute separately,
without using any pre-training or dataset augmentation, and we obtain new
state-of-the-art facial attribute classification results on the CelebA
benchmark. To test the stability of the networks, we generated adversarial
images -- formed by adding imperceptible non-random perturbations to original
inputs which result in classification errors -- via a novel fast flipping
attribute (FFA) technique. We show that FFA generates more adversarial examples
than other related algorithms, and that DCNNs for certain attributes are
generally robust to adversarial inputs, while DCNNs for other attributes are
not. This result is surprising because no DCNNs tested to date have exhibited
robustness to adversarial images without explicit augmentation in the training
procedure to account for adversarial examples. Finally, we introduce the
concept of natural adversarial samples, i.e., images that are misclassified but
can be easily turned into correctly classified images by applying small
perturbations. We demonstrate that natural adversarial samples commonly occur,
even within the training set, and show that many of these images remain
misclassified even with additional training epochs. This phenomenon is
surprising because correcting the misclassification, particularly when guided
by training data, should require only a small adjustment to the DCNN
parameters.


title: Maximally Recoverable Codes for Grid-like Topologies

abstract:
  The explosion in the volumes of data being stored online has resulted in
distributed storage systems transitioning to erasure coding based schemes. Yet,
the codes being deployed in practice are fairly short. In this work, we address
what we view as the main coding theoretic barrier to deploying longer codes in
storage: at large lengths, failures are not independent and correlated failures
are inevitable. This motivates designing codes that allow quick data recovery
even after large correlated failures, and which have efficient encoding and
decoding. We propose that code design for distributed storage be viewed as a
two-step process. The first step is choose a topology of the code, which
incorporates knowledge about the correlated failures that need to be handled,
and ensures local recovery from such failures. In the second step one specifies
a code with the chosen topology by choosing coefficients from a finite field.
In this step, one tries to balance reliability (which is better over larger
fields) with encoding and decoding efficiency (which is better over smaller
fields). This work initiates an in-depth study of this reliability/efficiency
tradeoff. We consider the field-size needed for achieving maximal
recoverability: the strongest reliability possible with a given topology. We
propose a family of topologies called grid-like topologies which unify a number
of topologies considered both in theory and practice, and prove a collection of
results about maximally recoverable codes in such topologies including the
first super-polynomial lower bound on the field size.


title: Light WIMP searches involving electron scattering

abstract:
  In the present work we examine the possibility for detecting electrons in
dark matter searches. These detectors are considered to be the most appropriate
for detecting light dark matter particles in the MeV region. We analyze
theoretically some key issues involved in such a detection and we perform
calculations for the expected rates employing reasonable theoretical models.


title: On the Evaluation of Dialogue Systems with Next Utterance Classification

abstract:
  An open challenge in constructing dialogue systems is developing methods for
automatically learning dialogue strategies from large amounts of unlabelled
data. Recent work has proposed Next-Utterance-Classification (NUC) as a
surrogate task for building dialogue systems from text data. In this paper we
investigate the performance of humans on this task to validate the relevance of
NUC as a method of evaluation. Our results show three main findings: (1) humans
are able to correctly classify responses at a rate much better than chance,
thus confirming that the task is feasible, (2) human performance levels vary
across task domains (we consider 3 datasets) and expertise levels (novice vs
experts), thus showing that a range of performance is possible on this type of
task, (3) automated dialogue systems built using state-of-the-art machine
learning methods have similar performance to the human novices, but worse than
the experts, thus confirming the utility of this class of tasks for driving
further research in automated dialogue systems.


title: Relative distance features for gait recognition with Kinect

abstract:
  Gait and static body measurement are important biometric technologies for
passive human recognition. Many previous works argue that recognition
performance based completely on the gait feature is limited. The reason for
this limited performance remains unclear. This study focuses on human
recognition with gait feature obtained by Kinect and shows that gait feature
can effectively distinguish from different human beings through a novel
representation -- relative distance-based gait features. Experimental results
show that the recognition accuracy with relative distance features reaches up
to 85%, which is comparable with that of anthropometric features. The
combination of relative distance features and anthropometric features can
provide an accuracy of more than 95%. Results indicate that the relative
distance feature is quite effective and worthy of further study in more general
scenarios (e.g., without Kinect).


title:
Leveraging Lexical Resources for Learning Entity Embeddings in
  Multi-Relational Data

abstract:
  Recent work in learning vector-space embeddings for multi-relational data has
focused on combining relational information derived from knowledge bases with
distributional information derived from large text corpora. We propose a simple
approach that leverages the descriptions of entities or phrases available in
lexical resources, in conjunction with distributional semantics, in order to
derive a better initialization for training relational models. Applying this
initialization to the TransE model results in significant new state-of-the-art
performances on the WordNet dataset, decreasing the mean rank from the previous
best of 212 to 51. It also results in faster convergence of the entity
representations. We find that there is a trade-off between improving the mean
rank and the hits@10 with this approach. This illustrates that much remains to
be understood regarding performance improvements in relational models.


title:
Morphology and Molecular Gas Fractions of Local Luminous Infrared
  Galaxies as a Function of Infrared Luminosity and Merger Stage

abstract:
  We present a new, detailed analysis of the morphologies and molecular gas
fractions for a complete sample of 65 local luminous infrared galaxies (LIRGs)
from the Great Observatories All-Sky LIRG Survey (GOALS) using high resolution
$I$-band images from The Hubble Space Telescope, the University of Hawaii 2.2m
Telescope and the Pan-STARRS1 Survey. Our classification scheme includes single
undisturbed galaxies, minor mergers, and major mergers, with the latter divided
into five distinct stages from pre-first pericenter passage to final nuclear
coalescence. We find that major mergers of molecular gas-rich spirals clearly
play a major role for all sources with $L_{\rm IR} > 10^{11.5} L_\odot $;
however, below this luminosity threshold, minor mergers and secular processes
dominate. Additionally, galaxies do not reach $L_{\rm IR} > 10^{12.0} L_\odot $
until late in the merger process when both disks are near final coalescence.
The mean molecular gas fraction (MGF $= M_{\rm H_2} / (M_* + M_{\rm H_2})$) for
non-interacting and early-stage major merger LIRGs is 18$\pm 2$%, which
increases to 33$\pm 3$%, for intermediate stage major merger LIRGs, consistent
with the hypothesis that, during the early-mid stages of major mergers, most of
the initial large reservoir of atomic gas (HI) at large galactocentric radii is
swept inward where it is converted into molecular gas (H$_2$).


title:
Effects of Two Successive Parity-Invariant Point Interactions on
  One-Dimensional Quantum Transmission: Resonance Conditions for the Parameter
  Space

abstract:
  We consider the scattering of a quantum particle by two independent,
successive parity-invariant point interactions in one dimension. The parameter
space for the two point interactions is given by the direct product of two
tori, which is described by four parameters. By investigating the effects of
the two point interactions on the transmission probability of plane wave, we
obtain the conditions for the parameter space under which perfect resonant
transmission occur. The resonance conditions are found to be described by
symmetric and anti-symmetric relations between the parameters.


title: An Introduction to Programming for Bioscientists: A Python-based Primer

abstract:
  Computing has revolutionized the biological sciences over the past several
decades, such that virtually all contemporary research in the biosciences
utilizes computer programs. The computational advances have come on many
fronts, spurred by fundamental developments in hardware, software, and
algorithms. These advances have influenced, and even engendered, a phenomenal
array of bioscience fields, including molecular evolution and bioinformatics;
genome-, proteome-, transcriptome- and metabolome-wide experimental studies;
structural genomics; and atomistic simulations of cellular-scale molecular
assemblies as large as ribosomes and intact viruses. In short, much of
post-genomic biology is increasingly becoming a form of computational biology.
The ability to design and write computer programs is among the most
indispensable skills that a modern researcher can cultivate. Python has become
a popular programming language in the biosciences, largely because (i) its
straightforward semantics and clean syntax make it a readily accessible first
language; (ii) it is expressive and well-suited to object-oriented programming,
as well as other modern paradigms; and (iii) the many available libraries and
third-party toolkits extend the functionality of the core language into
virtually every biological domain (sequence and structure analyses,
phylogenomics, workflow management systems, etc.). This primer offers a basic
introduction to coding, via Python, and it includes concrete examples and
exercises to illustrate the language's usage and capabilities; the main text
culminates with a final project in structural bioinformatics. A suite of
Supplemental Chapters is also provided. Starting with basic concepts, such as
that of a 'variable', the Chapters methodically advance the reader to the point
of writing a graphical user interface to compute the Hamming distance between
two DNA sequences.


title: Reconstruction of Ordinary Differential Equations From Time Series Data

abstract:
  We develop a numerical method to reconstruct systems of ordinary differential
equations (ODEs) from time series data without {\it a priori} knowledge of the
underlying ODEs using sparse basis learning and sparse function reconstruction.
We show that employing sparse representations provides more accurate ODE
reconstruction compared to least-squares reconstruction techniques for a given
amount of time series data. We test and validate the ODE reconstruction method
on known 1D, 2D, and 3D systems of ODEs. The 1D system possesses two stable
fixed points; the 2D system possesses an oscillatory fixed point with closed
orbits; and the 3D system displays chaotic dynamics on a strange attractor. We
determine the amount of data required to achieve an error in the reconstructed
functions to less than $0.1\%$. For the reconstructed 1D and 2D systems, we are
able to match the trajectories from the original ODEs even at long times. For
the 3D system with chaotic dynamics, as expected, the trajectories from the
original and reconstructed systems do not match at long times, but the
reconstructed and original models possess similar Lyapunov exponents. Now that
we have validated this ODE reconstruction method on known models, it can be
employed in future studies to identify new systems of ODEs using time series
data from deterministic systems for which there is no currently known ODE
model.


title: On regular graphs with four distinct eigenvalues

abstract:
  Let $\mathcal{G}(4,2)$ be the set of connected regular graphs with four
distinct eigenvalues in which exactly two eigenvalues are simple,
$\mathcal{G}(4,2,-1)$ (resp. $\mathcal{G}(4,2,0)$) the set of graphs belonging
to $\mathcal{G}(4,2)$ with $-1$ (resp. $0$) as an eigenvalue, and
$\mathcal{G}(4,\geq -1)$ the set of connected regular graphs with four distinct
eigenvalues and second least eigenvalue not less than $-1$. In this paper, we
prove the non-existence of connected graphs having four distinct eigenvalues in
which at least three eigenvalues are simple, and determine all the graphs in
$\mathcal{G}(4,2,-1)$. As a by-product of this work, we characterize all the
graphs belonging to $\mathcal{G}(4,\geq-1)$ and $\mathcal{G}(4,2,0)$,
respectively, and show that all these graphs are determined by their spectra.


title: Optimization Beyond Prediction: Prescriptive Price Optimization

abstract:
  This paper addresses a novel data science problem, prescriptive price
optimization, which derives the optimal price strategy to maximize future
profit/revenue on the basis of massive predictive formulas produced by machine
learning. The prescriptive price optimization first builds sales forecast
formulas of multiple products, on the basis of historical data, which reveal
complex relationships between sales and prices, such as price elasticity of
demand and cannibalization. Then, it constructs a mathematical optimization
problem on the basis of those predictive formulas. We present that the
optimization problem can be formulated as an instance of binary quadratic
programming (BQP). Although BQP problems are NP-hard in general and
computationally intractable, we propose a fast approximation algorithm using a
semi-definite programming (SDP) relaxation, which is closely related to the
Goemans-Williamson's Max-Cut approximation. Our experiments on simulation and
real retail datasets show that our prescriptive price optimization
simultaneously derives the optimal prices of tens/hundreds products with
practical computational time, that potentially improve 8.2% of gross profit of
those products.


title: Scaling violation and the magnetic equation of state in chiral models

abstract:
  The scaling behavior of the order parameter at the chiral phase transition,
the so-called magnetic equation of state, of strongly interacting matter is
studied within effective models. We explore universal and nonuniversal
structures near the critical point. These include the scaling functions, the
leading corrections to scaling, and the corresponding size of the scaling
window as well as their dependence on an external symmetry breaking field. We
consider two models in the mean-field approximation, the quark-meson and the
Polyakov loop extended quark-meson (PQM) models, and compare their critical
properties with a purely bosonic theory, the $O(N)$ linear sigma model in the
$N\rightarrow \infty$ limit. In these models the order parameter scaling
function is found analytically using the high temperature expansion of the
thermodynamic potential. The effects of a gluonic background on the
nonuniversal scaling parameters are studied within the PQM model.


title: Interferometry with Photon-Subtracted Thermal Light

abstract:
  We propose and implement a quantum procedure for enhancing the sensitivity
with which one can determine the phase shift experienced by a weak light beam
possessing thermal statistics in passing through an interferometer. Our
procedure entails subtracting exactly one (which can be generalized to m)
photons from the light field exiting an interferometer containing a
phase-shifting element in one of its arms. As a consequence of the process of
photon subtraction, and somewhat surprisingly, the mean photon number and
signal-to-noise ratio of the resulting light field are thereby increased,
leading to enhanced interferometry. This method can be used to increase
measurement sensitivity in a variety of practical applications, including that
of forming the image of an object illuminated only by weak thermal light.


title: Powers of the theta divisor and relations in the tautological ring

abstract:
  We show that the vanishing of the $(g+1)$-st power of the theta divisor on
the universal abelian variety $\mathcal{X}_g$ implies, by pulling back along a
collection of Abel--Jacobi maps, the vanishing results in the tautological ring
of $\mathcal{M}_{g,n}$ of Looijenga, Ionel, Graber--Vakil, and
Faber--Pandharipande. We also show that Pixton's double ramification cycle
relations, which generalize the theta vanishing relations and were recently
proved by the first and third authors, imply Theorem~$\star$ of Graber and
Vakil, and we provide an explicit algorithm for expressing any tautological
class on $\overline{\mathcal{M}}_{g,n}$ of sufficiently high codimension as a
boundary class.


title:
Photon pair generation by intermodal spontaneous four wave mixing in
  birefringent, weakly guiding optical fibers

abstract:
  We present a theoretical and experimental study of the generation of photon
pairs through the process of spontaneous four wave mixing (SFWM) in a few-mode,
birefringent fiber. Under these conditions, multiple SFWM processes are in fact
possible, each associated with a different combination of transverse modes for
the four waves involved. We show that in the weakly guiding regime, for which
the propagation modes may be well approximated by linearly polarized modes, the
departure from circular symmetry due to the fiber birefringence translates into
conservation rules which retain elements from azimuthal and rectangular
symmetries: both OAM and parity must be conserved for a process to be viable.
We have implemented a SFWM source based on a "bow-tie" birefringent fiber, and
have measured for a collection of pump wavelengths the SFWM spectra of each of
the signal and idler photons in coincidence with its partner photon. We have
used this information, together with knowledge of the transverse modes into
which the signal and idler photons are emitted, as input for a genetic
algorithm which accomplishes two tasks: i) the identification of the particular
SFWM processes which are present in the source, and ii) the characterization of
the fiber used.


title: 3D Lumped LC Resonators as Low Mass Axion Haloscopes

abstract:
  The axion is a hypothetical particle considered to be the most economical
solution to the strong CP problem. It can also be formulated as a compelling
component of dark matter. The haloscope, a leading axion detection scheme,
relies on the conversion of galactic halo axions into real photons inside a
resonant cavity structure in the presence of a static magnetic field, where the
generated photon frequency corresponds to the mass of the axion. For maximum
sensitivity it is key that the central frequency of the cavity mode structure
coincides with the frequency of the generated photon. As the mass of the axion
is unknown, it is necessary to perform searches over a wide range of
frequencies. Currently there are substantial regions of the promising
pre-inflationary low mass axion range without any viable proposals for
experimental searches. We show that 3D resonant LC circuits with separated
magnetic and electric fields, commonly known as re-entrant cavities, can be
sensitive dark matter haloscopes in this region, with frequencies inherently
lower than those achievable in the equivalent size of empty resonant cavity. We
calculate the sensitivity and accessible axion mass range of these experiments,
designing geometries to exploit and maximize the separated magnetic and
electric coupling of the axion to the cavity mode.


title: New maximal curves as ray class fields over Deligne-Lusztig curves

abstract:
  We construct new covers of the Suzuki and Ree curves which are maximal with
respect to the Hasse-Weil bound over suitable finite fields. These covers are
analogues of the Giulietti-Korchm\'aros curve, which covers the Hermitian curve
and is maximal over a base field extension. We show that the maximality of
these curves implies that of certain ray class field extensions of each of the
Deligne-Lusztig curves. Moreover, we show that the Giulietti-Korchm\'aros curve
is equal to the above-mentioned ray class field extension of the Hermitian
curve.


title:
Methods for Bayesian Variable Selection with Binary Response Data using
  the EM Algorithm

abstract:
  High-dimensional Bayesian variable selection problems are often solved using
computationally expensive Markov Chain Montle Carlo (MCMC) techniques.
Recently, a Bayesian variable selection technique was developed for continuous
data using the EM algorithm called EMVS. We extend the EMVS method to binary
data by proposing both a logistic and probit extension. To preserve the
computational speed of EMVS we also implemented the Stochastic Dual Coordinate
Descent (SDCA) algorithm. Further, we conduct two extensive simulation studies
to show the computational speed of both methods. These simulation studies
reveal the power of both methods to quickly identify the correct sparse model.
When these EMVS methods are compared to Stochastic Search Variable Selection
(SSVS), the EMVS methods surpass SSVS both in terms of computational speed and
correctly identifying significant variables. Finally, we illustrate the
effectiveness of both methods on two well-known gene expression datasets. Our
results mirror the results of previous examinations of these datasets with far
less computational cost.


title: On the complexity of Chooser-Picker positional games

abstract:
  Two new versions of the so-called Maker-Breaker Positional Games are defined
by J\'ozsef Beck in [{\em Combinatorica} {\bf 22}(2) (2002) 169--216]. He
defines two players, Picker and Chooser. In each round, Picker takes a pair of
elements not already selected and Chooser keeps one and returns the other to
Picker. In the Picker-Chooser version Picker plays as Maker and Chooser plays
as Breaker, while the roles are swapped in the Chooser-Picker version. The
outcome of these games is sometimes very similar to that of the traditional
Maker-Breaker games. Here we show that both Picker-Chooser and Chooser-Picker
games are NP-hard, which gives support to the paradigm that the games behave
similarly while being quite different in definition. We also investigate the
pairing strategies for Maker-Breaker games, and apply these results to the game
called "Snaky."


title:
Fiber-based photon-pair source capable of hybrid entanglement in
  frequency and transverse mode, controllably scalable to higher dimensions

abstract:
  We have designed and implemented a photon-pair source, based on the
spontaneous four wave mixing (SFWM) process in a few-mode fiber, in a geometry
which permits multiple, simultaneous SFWM processes, each associated with a
distinct combination of transverse modes for the four participating waves. In
our source: i) each process is group-velocity-matched so that it is, by design,
nearly-factorable, and ii) the spectral separation between neighboring
processes is greater than the marginal spectral width of each process.
Consequently, there is a direct correspondence between the joint amplitude of
each process and each of the Schmidt mode pairs of the overall two-photon
state. Our approach permits hybrid entanglement in discrete frequency and in
transverse mode, whereby control of the number of supported fiber transverse
modes allows scalability to higher dimensions while spectral filtering may be
used for straightforward Schmidt mode discrimination.


title:
Global Poincar\'e inequality on Graphs via Conical Curvature-Dimension
  Conditions

abstract:
  We introduce and study the conical curvature-dimension condition, $CCD(K,N)$,
for graphs. We show that $CCD(K,N)$ provides necessary and sufficient
conditions for the underlying graph to satisfy a sharp global Poincar\'e
inequality which in turn translates to a sharp lower bound for the first
eigenvalues of these graphs. Another application of the conical
curvature-dimension analysis is finding a sharp estimate on the curvature of
complete graphs.


title:
Relations such as Hypernymy: Identifying and Exploiting Hearst Patterns
  in Distributional Vectors for Lexical Entailment

abstract:
  We consider the task of predicting lexical entailment using distributional
vectors. We perform a novel qualitative analysis of one existing model which
was previously shown to only measure the prototypicality of word pairs. We find
that the model strongly learns to identify hypernyms using Hearst patterns,
which are well known to be predictive of lexical relations. We present a novel
model which exploits this behavior as a method of feature extraction in an
iterative procedure similar to Principal Component Analysis. Our model combines
the extracted features with the strengths of other proposed models in the
literature, and matches or outperforms prior work on multiple data sets.


title: A Note on Uniform Nonintegrability of Random Variables

abstract:
  In a recent paper \cite{CHR16}, Chandra, Hu and Rosalsky introduced the
notion of a sequence of random variables being uniformly nonintegrable, and
presented a list of interesting results on this uniform nonintegrability. In
this note, we introduce a weaker definition on uniform nonintegrability (W-UNI
for short) of random variables, present a necessary and sufficient condition
for W-UNI, and give two equivalent characterizations of W-UNI, one of which is
a W-UNI analogue of the celebrated de La Vall\'{e}e Poussin criterion for
uniform integrability. In addition, we give some remarks, one of which gives a
negative answer to the open problem raised in \cite{CHR16}.


title:
Upper bound for the average entropy production based on stochastic
  entropy extrema

abstract:
  The second law of thermodynamics, which asserts the non-negativity of the
average total entropy production of a combined system and its environment, is a
direct consequence of applying Jensen's inequality to a fluctuation relation.
It is also possible, through this inequality, to determine an upper bound of
the average total entropy production based on the entropies along the most
extreme stochastic trajectories. In this work, we construct an upper bound
inequality of the average of a convex function over a domain whose average is
known. When applied to the various fluctuation relations, the upper bounds of
the average total entropy production are established. Finally, by employing the
result of Neri, Rold\'an, and J\"ulicher [Phys. Rev. X 7, 011019 (2017)], we
are able to show that the average total entropy production is bounded only by
the total entropy production supremum, and vice versa, for a general
non-equilibrium stationary system.


title: Parallel Algorithms for Summing Floating-Point Numbers

abstract:
  The problem of exactly summing n floating-point numbers is a fundamental
problem that has many applications in large-scale simulations and computational
geometry. Unfortunately, due to the round-off error in standard floating-point
operations, this problem becomes very challenging. Moreover, all existing
solutions rely on sequential algorithms which cannot scale to the huge datasets
that need to be processed.
  In this paper, we provide several efficient parallel algorithms for summing n
floating point numbers, so as to produce a faithfully rounded floating-point
representation of the sum. We present algorithms in PRAM, external-memory, and
MapReduce models, and we also provide an experimental analysis of our MapReduce
algorithms, due to their simplicity and practical efficiency.


title: Symmetry Breaking in Pedestrian Dynamics

abstract:
  When two pedestrians travelling in opposite directions approach one another,
each must decide on which side (the left or the right) they will attempt to
pass. If both make the same choice then passing can be completed with ease,
while if they make opposite choices an embarrassing stand-off or collision can
occur. Pedestrians who encounter each other frequently can establish "social
norms" that bias this decision. In this study we investigate the effect of
binary decision-making by pedestrians when passing on the dynamics of
pedestrian flows in order to study the emergence of a social norm in crowds
with a mixture of individual biases. Such a situation may arise, for instance,
when individuals from different communities mix at a large sporting event or at
transport hubs. We construct a phase diagram that shows that a social norm can
still emerge provided pedestrians are sufficiently attentive to the choices of
others in the crowd. We show that this collective behaviour has the potential
to greatly influence the dynamics of pedestrians, including the breaking of
symmetry by the formation of lanes.


title: The Blockchain Anomaly

abstract:
  Most popular blockchain solutions, like Bitcoin, rely on proof-of-work,
guaranteeing that the output of the consensus is agreed upon with high
probability. However, this probability depends on the delivery of messages and
that the computational power of the system is sufficiently scattered among
pools of nodes in the network so that no pool can mine more blocks faster than
the crowd. New approaches, like Ethereum, generalise the proof-of-work approach
by letting individuals deploy their own private blockchain with high
transaction throughput. As companies are starting to deploy private chains, it
has become crucial to better understand the guarantees blockchains offer in
such a small and controlled environment.
  In this paper, we present the \emph{Blockchain Anomaly}, an execution that we
experienced when building our private chain at NICTA/Data61. Even though this
anomaly has never been acknowledged before, it may translate into dramatic
consequences for the user of blockchains. Named after the infamous Paxos
anomaly, this anomaly makes dependent transactions, like "Bob sends money to
Carole after he received money from Alice" impossible. This anomaly relies on
the fact that existing blockchains do not ensure consensus safety
deterministically: there is no way for Bob to make sure that Alice actually
sent him coins without Bob using an external mechanism, like converting these
coins into a fiat currency that allows him to withdraw. We also explore smart
contracts as a potential alternative to transactions in order to freeze coins,
and show implementations of smart contract that can suffer from the Blockchain
anomaly and others that may cope with it.


title:
Conformity of macroscopic behavior to local properties in the catalytic
  ammonia synthesis and oscillatory reactions on metal surfaces

abstract:
  Unique catalytic potential of metal surfaces has encouraged a great number of
basic and applied studies. The manuscript highlights the general regularities
in a field on the grounds of strong interrelation between catalytic, kinetic
and thermodynamic behaviour of the reaction system. The trials of the catalytic
NH3 synthesis and the oscillatory NO+H2 reaction have revealed that the
thermodynamics of the local structure determines the properties and
multiplicity of the reaction intermediates enabling the peculiar macroscopic
kinetics and specific catalytic activity. Structure and activity of catalytic
sites are correlated within a realistic model, where total undercoordination of
adjacent surface atoms and enthalpy of local reaction is taken as a descriptor
for structure and activity, respectively. The model has specified the resonant
catalytic centers for NH3 synthesis on metal surfaces in close agreement with
experimental data. The basal planes of noble metals are less active than Fe-
and Ru-based catalysts, whereas an extraordinary activity of small Pt, Ir and
Rh clusters can be expected. A strong advantage of imperfections compared to
perfect areas in the surface wave nucleation is evaluated. Isothermal rate
oscillations in open heterogeneous catalytic reaction systems are expected
under the multiplicity of reaction intermediates fairly different in activity,
providing the steady state and reaction rout multiplicity. Switching between
active and inactive kinetic brunches gives rise to the explosive coverage
changeover that can be visualized as a traveling wave. A single pattern of
oscillations in the NO+H2 reaction includes the key role of intermediate NHad
species providing the catalytic removal of strongly bound nitrogen. The driving
forces, the feedback, and chemical interactions within the traveling waves are
clearly understood.


title: Beyond Caption To Narrative: Video Captioning With Multiple Sentences

abstract:
  Recent advances in image captioning task have led to increasing interests in
video captioning task. However, most works on video captioning are focused on
generating single input of aggregated features, which hardly deviates from
image captioning process and does not fully take advantage of dynamic contents
present in videos. We attempt to generate video captions that convey richer
contents by temporally segmenting the video with action localization,
generating multiple captions from multiple frames, and connecting them with
natural language processing techniques, in order to generate a story-like
caption. We show that our proposed method can generate captions that are richer
in contents and can compete with state-of-the-art method without explicitly
using video-level features as input.


title:
Metropolis-Hastings algorithms with autoregressive proposals, and a few
  examples

abstract:
  We analyse computational efficiency of Metropolis-Hastings algorithms with
stochastic AR(1) process proposals. These proposals include, as a subclass,
discretized Langevin diffusion (e.g. MALA) and discretized Hamiltonian dynamics
(e.g. HMC).
  We derive expressions for the expected acceptance rate and expected jump size
for MCMC methods with general stochastic AR(1) process proposals for the case
where the target distribution is absolutely continuous with respect to a
Gaussian and the covariance of the Gaussian is allowed to have off-diagonal
terms. This allows us to extend what is known about several MCMC methods as
well as determining the efficiency of new MCMC methods of this type. In the
special case of Hybrid Monte Carlo, we can determine the optimal integration
time and the effect of the choice of mass matrix.
  By including the effect of Metropolis-Hastings we also extend results by Fox
and Parker, who used matrix splitting techniques to analyse the performance and
improve efficiency of stochastic AR(1) processes for sampling from Gaussian
distributions.


title:
Resilience of antagonistic networks with regard to the effects of
  initial failures and degree-degree correlations

abstract:
  In this study, we investigate the resilience of duplex networked layers
($\alpha$ and $\beta$) coupled with antagonistic interlinks, each layer of
which inhibits its counterpart at the microscopic level, changing the following
factors: whether the influence of the initial failures in $\alpha$ remains
(quenched (Case Q)) or not (free (Case F)); the effect of intralayer
degree-degree correlations in each layer and interlayer degree-degree
correlations; and the type of the initial failures, such as random failures
(RFs) or targeted attacks (TAs). We illustrate that the percolation processes
repeat in both Cases Q and F, although only in Case F are nodes that initially
failed reactivated. To analytically evaluate the resilience of each layer, we
develop a methodology based on the cavity method for deriving the size of a
giant component (GC). Strong hysteresis, which is ignored in the standard
cavity analysis, is observed in the repetition of the percolation processes
particularly in Case F. To handle this, we heuristically modify interlayer
messages for macroscopic analysis, the utility of which is verified by
numerical experiments. The percolation transition in each layer is continuous
in both Cases Q and F. We also analyze the influences of degree-degree
correlations on the robustness of layer $\alpha$, in particular for the case of
TAs. The analysis indicates that the critical fraction of initial failures that
makes the GC size in layer $\alpha$ vanish depends only on its intralayer
degree-degree correlations. Although our model is defined in a somewhat
abstract manner, it may have relevance to ecological systems that are composed
of endangered species (layer $\alpha$) and invaders (layer $\beta$), the former
of which are damaged by the latter whereas the latter are exterminated in the
areas where the former are active.