title:
Benford's distribution in extrasolar world: Do the exoplanets follow
  Benford's distribution?

abstract:
  In many real life situations, it is observed that the first digits (i.e.,
$1,2,\ldots,9$) of a numerical data-set, which is expressed using decimal
system, do not follow a random distribution. Instead, smaller numbers are
favoured by nature in accordance with a logarithmic distribution law, which is
referred to as Benford's law. The existence and applicability of this empirical
law have been extensively studied by physicists, accountants, computer
scientists, mathematicians, statisticians, etc., and it has been observed that
a large number of data-sets related to diverse problems follow this
distribution. However, applicability of Benford's law has been hardly tested
for extrasolar objects. Motivated by this fact, this paper investigates the
existence of Benford's distribution in the extrasolar world using Kepler data
for exoplanets. The investigation has revealed the presence of Benford's
distribution in various physical properties of these exoplanets. Further,
Benford goodness parameters are computed to provide a quantitative measure of
coincidence of real data with the ideal values obtained from Benford's
distribution. The quantitative analysis and the plots have revealed that
several physical parameters associated with the exoplanets (e.g., mass, volume,
density, orbital semi-major axis, orbital period, and radial velocity) nicely
follow Benford's distribution, whereas some physical parameters (e.g., total
proper motion, stellar age and stellar distance) moderately follow the
distribution, and some others (e.g., longitude, radius, and effective
temperature) do not follow Benford's distribution. Further, some specific
comments have been made on the possible generalizations of the obtained result,
its potential applications in analyzing data-set of candidate exoplanets, and
how interested readers can perform similar investigations on other interesting
data-sets.


title: Two Discourse Driven Language Models for Semantics

abstract:
  Natural language understanding often requires deep semantic knowledge.
Expanding on previous proposals, we suggest that some important aspects of
semantic knowledge can be modeled as a language model if done at an appropriate
level of abstraction. We develop two distinct models that capture semantic
frame chains and discourse information while abstracting over the specific
mentions of predicates and entities. For each model, we investigate four
implementations: a "standard" N-gram language model and three discriminatively
trained "neural" language models that generate embeddings for semantic frames.
The quality of the semantic language models (SemLM) is evaluated both
intrinsically, using perplexity and a narrative cloze test and extrinsically -
we show that our SemLM helps improve performance on semantic natural language
processing tasks such as co-reference resolution and discourse parsing.


title:
Discrimination between spin-dependent charge transport and spin
  dependent recombination in {\pi}-conjugated polymers by correlated current
  and electroluminescence-detected magnetic resonance

abstract:
  Spin-dependent processes play a crucial role in organic electronic devices.
Spin coherence can give rise to spin mixing due to a number of processes such
as hyperfine coupling, and leads to a range of magnetic field effects. However,
it is not straightforward to differentiate between pure single-carrier
spin-dependent transport processes which control the current and therefore the
electroluminescence, and spin-dependent electron-hole recombination which
determines the electroluminescence yield and in turn modulates the current. We
therefore investigate the correlation between the dynamics of spin-dependent
electric current and spin-dependent electroluminescence in two derivatives of
the conjugated polymer poly(phenylene-vinylene) using simultaneously measured
pulsed electrically detected (pEDMR) and optically detected (pODMR) magnetic
resonance spectroscopy. This experimental approach requires careful analysis of
the transient response functions under optical and electrical detection. At
room temperature and under bipolar charge-carrier injection conditions, a
correlation of the pEDMR and the pODMR signals is observed, consistent with the
hypothesis that the recombination currents involve spin-dependent electronic
transitions. This observation is inconsistent with the hypothesis that these
signals are caused by spin-dependent charge carrier transport. These results
therefore provide no evidence that supports earlier claims that spindependent
transport plays a role for room temperature magnetoresistance effects. At low
temperatures, however, the correlation between pEDMR and pODMR is weakened,
demonstrating that more than one spin-dependent process influences the
optoelectronic materials properties.


title:
Hierarchical Data Generator based on Tree-Structured Stick Breaking
  Process for Benchmarking Clustering Methods

abstract:
  Object Cluster Hierarchies is a new variant of Hierarchical Cluster Analysis
that gains interest in the field of Machine Learning. Being still at an early
stage of development, the lack of tools for systematic analysis of Object
Cluster Hierarchies inhibits its further improvement. In this paper we address
this issue by proposing a generator of synthetic hierarchical data that can be
used for benchmarking Object Cluster Hierarchy methods. The article presents a
thorough empirical and theoretical analysis of the generator and provides
guidance on how to control its parameters. Conducted experiments show the
usefulness of the data generator that is capable of producing a wide range of
differently structured data. Further, benchmarking datasets that mirror the
most common types of hierarchies are generated and made available to the
public, together with the developed generator
(http://kio.pwr.edu.pl/?page\_id=396).


title: Multi-terminal multi-junction dc SQUID for nanoscale magnetometry

abstract:
  Miniaturization of superconducting quantum interference devices (SQUIDs) is
of major importance for the development of sensitive scanning nanoscale
magnetometry tools. The high sensitivity of nanoSQUIDs is restricted, however,
to only particular periodic values of the applied magnetic field, making
accurate measurements at intermediate values of the field impossible. We
present a theoretical investigation of a multi-terminal, multi-junction SQUID
(mSQUID) that lifts this limitation by providing electrical means for a
continuous shift of the quantum interference pattern with respect to the
applied field. Analysis of 4-terminal, 4-junction and 3-terminal, 3-junction
mSQUIDs shows that operation at maximum sensitivity can be obtained at any
value of the magnetic field by applying control current to the extra terminals.
The model describes the variation and the shift of the interference pattern as
a function of the control currents, junction asymmetries, and the mSQUID
inductance. The mSQUID is also shown to provide a direct measurement of the
current-phase relations of superconducting junctions. The derived model
provides a quantitative description of the recently developed multi-terminal
nanoSQUID-on-tip.


title: Laser spectroscopy of cold molecules

abstract:
  This paper reviews the recent results in high-resolution spectroscopy on cold
molecules. Laser spectroscopy of cold molecules addresses issues of symmetry
violation, like in the search for the electric dipole moment of the electron
and the studies on energy differences in enantiomers of chiral species; tries
to improve the precision to which fundamental physical constants are known and
tests for their possible variation in time and space; tests quantum
electrodynamics, and searches for a fifth force. Further, we briefly review the
recent technological progresses in the fields of cold molecules and
mid-infrared lasers, which are the tools that mainly set the limits for the
resolution that is currently attainable in the measurements.


title:
Collective Ratchet Effects and Reversals for Active Matter Particles on
  Quasi-One-Dimensional Asymmetric Substrates

abstract:
  Using computer simulations, we study a two-dimensional system of sterically
interacting self-mobile run-and-tumble disk-shaped particles with an underlying
periodic quasi-one-dimensional asymmetric substrate, and show that a rich
variety of collective active ratchet behaviors arise as a function of particle
density, activity, substrate strength, and substrate period. The ratchet
efficiency is nonmonotonic since the ratcheting is enhanced by increased
activity but diminished by the onset of self-clustering of the active
particles. Increasing the particle density decreases the ratchet efficiency for
weak substrates but increases the ratchet efficiency for strong substrates due
to collective hopping events. At the highest particle densities, the ratchet
motion is destroyed by a self-jamming effect. We show that it is possible to
realize reversals of the ratchet effect, where the net flux of particles is
along the hard rather than the easy direction of the substrate asymmetry. The
reversals occur in the strong substrate limit when multiple rows of active
particles can be confined in each substrate minimum, permitting emergent
particle-like excitations to appear that experience an inverted effective
substrate potential. We map out a phase diagram of the forward and reverse
ratchet effects as a function of the particle density, activity, and substrate
properties.


title: Using Visual Analytics to Interpret Predictive Machine Learning Models

abstract:
  It is commonly believed that increasing the interpretability of a machine
learning model may decrease its predictive power. However, inspecting
input-output relationships of those models using visual analytics, while
treating them as black-box, can help to understand the reasoning behind
outcomes without sacrificing predictive quality. We identify a space of
possible solutions and provide two examples of where such techniques have been
successfully used in practice.


title:
Quark-gluon double parton distributions in the light-front dressed quark
  model

abstract:
  We study parton distributions for two partons, a quark and a gluon, in the
light-front dressed quark model, with focus on correlations between the two
partons. The model calculation leads to sizable spin-spin and spin-kinematic
correlations of interest for studies of double parton scattering (DPS) in
high-energy collisions. In particular, we find that the transverse dependence
of the double parton distributions (DPDs) does not factorize within the model.
The results gives insight to the strengths of correlations in different
kinematical regions, which can help in constructing input DPDs in cross section
calculations.


title: Reducing MSE in estimation of heavy tails: a Bayesian approach

abstract:
  Bias reduction in tail estimation has received considerable interest in
extreme value analysis. Estimation methods that minimize the bias while keeping
the mean squared error (MSE) under control, are especially useful when applying
classical methods such as the Hill (1975) estimator. In Caeiro et al. (2005)
minimum variance reduced bias estimators of the Pareto tail index were first
proposed where the bias is reduced without increasing the variance with respect
to the Hill estimator. This method is based on adequate external estimation of
a pair of second-order parameters. Here we revisit this problem from a Bayesian
point of view starting from the extended Pareto distribution (EPD)
approximation to excesses over a high threshold, as developed in Beirlant et
al. (2009) using maximum likelihood (ML) estimation. Using asymptotic
considerations, we derive an appropriate choice of priors leading to a Bayes
estimator for which the MSE curve is a weighted average of the Hill and EPD-ML
MSE curves for a large range of thresholds, under the same conditions as in
Beirlant et al.(2009). A similar result is obtained for tail probability
estimation. Simulations show surprisingly good MSE performance with respect to
the existing estimators.


title:
ZNNi - Maximizing the Inference Throughput of 3D Convolutional Networks
  on Multi-Core CPUs and GPUs

abstract:
  Sliding window convolutional networks (ConvNets) have become a popular
approach to computer vision problems such as image segmentation, and object
detection and localization. Here we consider the problem of inference, the
application of a previously trained ConvNet, with emphasis on 3D images. Our
goal is to maximize throughput, defined as average number of output voxels
computed per unit time. Other things being equal, processing a larger image
tends to increase throughput, because fractionally less computation is wasted
on the borders of the image. It follows that an apparently slower algorithm may
end up having higher throughput if it can process a larger image within the
constraint of the available RAM. We introduce novel CPU and GPU primitives for
convolutional and pooling layers, which are designed to minimize memory
overhead. The primitives include convolution based on highly efficient pruned
FFTs. Our theoretical analyses and empirical tests reveal a number of
interesting findings. For some ConvNet architectures, cuDNN is outperformed by
our FFT-based GPU primitives, and these in turn can be outperformed by our CPU
primitives. The CPU manages to achieve higher throughput because of its fast
access to more RAM. A novel primitive in which the GPU accesses host RAM can
significantly increase GPU throughput. Finally, a CPU-GPU algorithm achieves
the greatest throughput of all, 10x or more than other publicly available
implementations of sliding window 3D ConvNets. All of our code has been made
available as open source project.


title: Bidimensionality and Kernels

abstract:
  Bidimensionality Theory was introduced by [E.D. Demaine, F.V. Fomin,
M.Hajiaghayi, and D.M. Thilikos. Subexponential parameterized algorithms on
graphs of bounded genus and H-minor-free graphs, J. ACM, 52 (2005),
pp.866--893] as a tool to obtain sub-exponential time parameterized algorithms
on H-minor-free graphs. In [E.D. Demaine and M.Hajiaghayi, Bidimensionality:
new connections between FPT algorithms and PTASs, in Proceedings of the 16th
Annual ACM-SIAM Symposium on Discrete Algorithms (SODA), SIAM, 2005,
pp.590--601] this theory was extended in order to obtain polynomial time
approximation schemes (PTASs) for bidimensional problems. In this work, we
establish a third meta-algorithmic direction for bidimensionality theory by
relating it to the existence of linear kernels for parameterized problems. In
particular, we prove that every minor (respectively contraction) bidimensional
problem that satisfies a separation property and is expressible in Countable
Monadic Second Order Logic (CMSO), admits a linear kernel for classes of graphs
that exclude a fixed graph (respectively an apex graph) H as a minor. Our
results imply that a multitude of bidimensional problems g graph classes. For
most of these problems no polynomial kernels on H-minor-free graphs were known
prior to our work.


title: Potential of EPUB3 for Digital Textbooks in Higher Education

abstract:
  The e-book market is currently in a strong upswing. This research study deals
with the question which practical uses the e-book format EPUB3 offers for
(higher) education. By means of a didactic content analysis, a range of
interactive exercise types were developed as a result of conversations with
teachers. For this purpose, a didactic and technical concept has been
developed. Different kinds of exercises were prototypically implemented in an
e-book. Finally, a brief overview reflects the present state of the current
e-book readers. A subsequent discussion illuminates the strengths and
weaknesses of the format. In summary, it can be remarked that EPUB3 is suitable
for a variety of different exercises and that it is able to serve as a basic
format for forthcoming digital textbooks. Furthermore the openness of EPUB3
will assist Open Learning and Teaching in a meaningful way.


title: Dynamic Atomic Congestion Games with Seasonal Flows

abstract:
  We propose a model of discrete time dynamic congestion games with atomic
players and a single source-destination pair. The latencies of edges are
composed by free-flow transit times and possible queuing time due to capacity
constraints. We give a precise description of the dynamics induced by the
individual strategies of players and of the corresponding costs, either when
the traffic is controlled by a planner, or when players act selfishly. In
parallel networks, optimal and equilibrium behavior eventually coincides, but
the selfish behavior of the first players has consequences that cannot be
undone and are paid by all future generations. In more general topologies, our
main contributions are three-fold.
  First, we show that equilibria are usually not unique. In particular, we
prove that there exists a sequence of networks such that the price of anarchy
is equal to $n-1$, where $n$ is the number of vertices, and the price of
stability is equal to 1.
  Second, we illustrate a new dynamic version of Braess's paradox: the presence
of initial queues in a network may decrease the long-run costs in equilibrium.
This paradox may arise even in networks for which no Braess's paradox was
previously known.
  Third, we propose an extension to model seasonalities by assuming that
departure flows fluctuate periodically over time. We introduce a measure that
captures the queues induced by periodicity of inflows. This measure is the
increase in costs compared to uniform departures for optimal and equilibrium
flows in parallel networks.


title: Baer and Baer *-ring characterizations of Leavitt path algebras

abstract:
  We characterize Leavitt path algebras which are Rickart, Baer, and Baer
$*$-rings in terms of the properties of the underlying graph. In order to treat
non-unital Leavitt path algebras as well, we generalize these
annihilator-related properties to locally unital rings and provide a more
general characterizations of Leavitt path algebras which are locally Rickart,
locally Baer, and locally Baer $*$-rings. Leavitt path algebras are also graded
rings and we formulate the graded versions of these annihilator-related
properties and characterize Leavitt path algebras having those properties as
well.
  Our characterizations provide a quick way to generate a wide variety of
examples of rings. For example, creating a Baer and not a Baer $*$-ring, a
Rickart $*$-ring which is not Baer, or a Baer and not a Rickart $*$-ring, is
straightforward using the graph-theoretic properties from our results. In
addition, our characterizations showcase more properties which distinguish
behavior of Leavitt path algebras from their $C^*$-algebra counterparts. For
example, while a graph $C^*$-algebra is Baer (and a Baer $*$-ring) if and only
if the underlying graph is finite and acyclic, a Leavitt path algebra is Baer
if and only if the graph is finite and no cycle has an exit, and it is a Baer
$*$-ring if and only if the graph is a finite disjoint union of graphs which
are finite and acyclic or loops.


title: Structured Stochastic Linear Bandits

abstract:
  The stochastic linear bandit problem proceeds in rounds where at each round
the algorithm selects a vector from a decision set after which it receives a
noisy linear loss parameterized by an unknown vector. The goal in such a
problem is to minimize the (pseudo) regret which is the difference between the
total expected loss of the algorithm and the total expected loss of the best
fixed vector in hindsight. In this paper, we consider settings where the
unknown parameter has structure, e.g., sparse, group sparse, low-rank, which
can be captured by a norm, e.g., $L_1$, $L_{(1,2)}$, nuclear norm. We focus on
constructing confidence ellipsoids which contain the unknown parameter across
all rounds with high-probability. We show the radius of such ellipsoids depend
on the Gaussian width of sets associated with the norm capturing the structure.
Such characterization leads to tighter confidence ellipsoids and, therefore,
sharper regret bounds compared to bounds in the existing literature which are
based on the ambient dimensionality.


title:
DeepStance at SemEval-2016 Task 6: Detecting Stance in Tweets Using
  Character and Word-Level CNNs

abstract:
  This paper describes our approach for the Detecting Stance in Tweets task
(SemEval-2016 Task 6). We utilized recent advances in short text categorization
using deep learning to create word-level and character-level models. The choice
between word-level and character-level models in each particular case was
informed through validation performance. Our final system is a combination of
classifiers using word-level or character-level models. We also employed novel
data augmentation techniques to expand and diversify our training dataset, thus
making our system more robust. Our system achieved a macro-average precision,
recall and F1-scores of 0.67, 0.61 and 0.635 respectively.


title:
Measuring temperature and ammonia hydrate ice on Charon in 2015 from
  Keck/OSIRIS spectra

abstract:
  In this work we investigated the longitudinal (zonal) variability of H$_2$O
and ammonia (NH$_3$) hydrate ices on the surface of Charon through analysis of
the 1.65 $\mu$m and 2.21 $\mu$m absorption features, respectively.
Near-infrared spectra presented here were obtained between 2015-07-14 and
2015-08-30 UT with the OSIRIS integral field spectrograph on Keck I. Spectra
centered on six different sub-observer longitudes were obtained through the Hbb
(1.473-1.803 $\mu$m) and Kbb (1.965-2.381 $\mu$m) filters. Gaussian functions
were fit to the aforementioned bands to obtain information on band center, band
depth, full width at half maximum, and band area. The shift in the band center
of the temperature-dependent 1.65 $\mu$m feature was used to calculate the
H$_2$O ice temperature. The mean temperature of the ice on the observable
portion of Charon's surface is 45$\pm$14 K and we report no statistically
significant variations in temperature across the surface. We hypothesize that
the crystalline and amorphous phases of water ice reached equilibrium over 3.5
Gyr ago, with thermal recrystallization balancing the effects of irradiation
amorphization. We do not believe that cryovolcanism is necessary to explain the
presence of crystalline water ice on the surface of Charon. Absorption from
ammonia species is detected between 12$^{\circ}$ and 290$^{\circ}$, in
agreement with results from New Horizons. Ongoing diffusion of ammonia through
the rocky mantle and upper layer of water ice is one possible mechanism for
maintaining its presence in Charon's surface ice. Reduced Charon spectra
corrected for telluric and solar absorption are available as supplementary
online material.


title: Tensor Contractions with Extended BLAS Kernels on CPU and GPU

abstract:
  Tensor contractions constitute a key computational ingredient of numerical
multi-linear algebra. However, as the order and dimension of tensors grow, the
time and space complexities of tensor-based computations grow quickly. Existing
approaches for tensor contractions typically involves explicit copy and
transpose operations. In this paper, we propose and evaluate a new BLAS-like
primitive STRIDEDBATCHEDGEMM that is capable of performing a wide range of
tensor contractions on CPU and GPU efficiently. Through systematic
benchmarking, we demonstrate the advantages of our approach over conventional
approaches. Concretely, we implement the Tucker decomposition and show that
using our kernels yields 100x speedup as compared to the implementation using
existing state-of-the-art libraries.


title: Long-distance singularities in multi-leg scattering amplitudes

abstract:
  We report on the recent completion of the three-loop calculation of the soft
anomalous dimension in massless gauge-theory scattering amplitudes. This brings
the state-of-the-art knowledge of long-distance singularities in multi-leg QCD
amplitudes with any number of massless particles to three loops. The result
displays some novel features: this is the first time non-dipole corrections
appear, which directly correlate the colour and kinematic degrees of freedom of
four coloured partons. We find that non-dipole corrections appear at three
loops also for three coloured partons, but these are independent of the
kinematics. The final result is remarkably simple when expressed in terms of
single-valued harmonic polylogarithms, and it satisfies several non-trivial
constraints. In particular, it is consistent with the high-energy limit
behaviour and it satisfies the expected factorization properties in
two-particle collinear limits.


title: Electrical Resistance Tomography of Conductive Thin Films

abstract:
  The Electrical Resistance Tomography (ERT) technique is applied to the
measurement of sheet conductance maps of both uniform and patterned conductive
thin films. Images of the sheet conductance spatial distribution, and local
conductivity values are obtained. Test samples are tin oxide films on glass
substrates, with electrical contacts on the sample boundary, some samples are
deliberately patterned in order to induce null conductivity zones of known
geometry while others contain higher conductivity inclusions. Four-terminal
resistance measurements among the contacts are performed with a scanning setup.
The ERT reconstruction is performed by a numerical algorithm based on the total
variation regularization and the L-curve method. ERT correctly images the sheet
conductance spatial distribution of the samples. The reconstructed conductance
values are in good quantitative agreement with independent measurements
performed with the van der Pauw and the four-point probe methods.


title: Socially-Informed Timeline Generation for Complex Events

abstract:
  Existing timeline generation systems for complex events consider only
information from traditional media, ignoring the rich social context provided
by user-generated content that reveals representative public interests or
insightful opinions. We instead aim to generate socially-informed timelines
that contain both news article summaries and selected user comments. We present
an optimization framework designed to balance topical cohesion between the
article and comment summaries along with their informativeness and coverage of
the event. Automatic evaluations on real-world datasets that cover four complex
events show that our system produces more informative timelines than
state-of-the-art systems. In human evaluation, the associated comment summaries
are furthermore rated more insightful than editor's picks and comments ranked
highly by users.


title: A dichotomy for CLT in total variation

abstract:
  Let $\eta_i$, $i\ge 1$, be a sequence of independent and identically
distributed random variables with finite third moment, and let $\Delta_n$ be
the total variation distance between the distribution of
$S_n:=\sum_{i=1}^n\eta_i$ and the normal distribution with the same mean and
variance. In this note, we show the dichotomy that either $\Delta_n=1$ for all
$n$ or $\Delta_n=O\left(n^{-1/2}\right)$.


title: The Gamma question for many-one degrees

abstract:
  A set $A$ is coarsely computable with density $r \in [0,1]$ if there is an
algorithm for deciding membership in $A$ which always gives a (possibly
incorrect) answer, and which gives a correct answer with density at least $r$.
To any Turing degree $\mathbf{a}$ we can assign a value $\Gamma_T(\mathbf{a})$:
the minimum, over all sets $A$ in $\mathbf{a}$, of the highest density at which
$A$ is coarsely computable. The closer $\Gamma_T(\mathbf{a})$ is to $1$, the
closer $\mathbf{a}$ is to being computable. Andrews, Cai, Diamondstone,
Jockush, and Lempp noted that $\Gamma_T$ can take on the values $0$, $1/2$, and
$1$, but not any values in strictly between $1/2$ and $1$. They asked whether
the value of $\Gamma_T$ can be strictly between $0$ and $1/2$. This is the
Gamma question.
  Replacing Turing degrees by many-one degrees, we get an analogous question,
and the same arguments show that $\Gamma_m$ can take on the values $0$, $1/2$,
and $1$, but not any values strictly between $1/2$ and $1$. We will show that
for any $r \in [0,1/2]$, there is an $m$-degree $\mathbf{a}$ with
$\Gamma_m(\mathbf{a}) = r$. Thus the range of $\Gamma_m$ is $[0,1/2] \cup
\{1\}$.
  Benoit Monin has recently announced a solution to the Gamma question for
Turing degrees. Interestingly, his solution gives the opposite answer: the only
possible values of $\Gamma_T$ are $0$, $1/2$, and $1$.


title: Query-Focused Opinion Summarization for User-Generated Content

abstract:
  We present a submodular function-based framework for query-focused opinion
summarization. Within our framework, relevance ordering produced by a
statistical ranker, and information coverage with respect to topic distribution
and diverse viewpoints are both encoded as submodular functions. Dispersion
functions are utilized to minimize the redundancy. We are the first to evaluate
different metrics of text similarity for submodularity-based summarization
methods. By experimenting on community QA and blog summarization, we show that
our system outperforms state-of-the-art approaches in both automatic evaluation
and human evaluation. A human evaluation task is conducted on Amazon Mechanical
Turk with scale, and shows that our systems are able to generate summaries of
high overall quality and information diversity.


title:
A Survey of Pansharpening Methods with A New Band-Decoupled Variational
  Model

abstract:
  Most satellites decouple the acquisition of a panchromatic image at high
spatial resolution from the acquisition of a multispectral image at lower
spatial resolution. Pansharpening is a fusion technique used to increase the
spatial resolution of the multispectral data while simultaneously preserving
its spectral information. In this paper, we consider pansharpening as an
optimization problem minimizing a cost function with a nonlocal regularization
term. The energy functional which is to be minimized decouples for each band,
thus permitting the application to misregistered spectral components. This
requirement is achieved by dropping the, commonly used, assumption that relates
the spectral and panchromatic modalities by a linear transformation. Instead, a
new constraint that preserves the radiometric ratio between the panchromatic
and each spectral component is introduced. An exhaustive performance comparison
of the proposed fusion method with several classical and state-of-the-art
pansharpening techniques illustrates its superiority in preserving spatial
details, reducing color distortions, and avoiding the creation of aliasing
artifacts.


title:
A Piece of My Mind: A Sentiment Analysis Approach for Online Dispute
  Detection

abstract:
  We investigate the novel task of online dispute detection and propose a
sentiment analysis solution to the problem: we aim to identify the sequence of
sentence-level sentiments expressed during a discussion and to use them as
features in a classifier that predicts the DISPUTE/NON-DISPUTE label for the
discussion as a whole. We evaluate dispute detection approaches on a newly
created corpus of Wikipedia Talk page disputes and find that classifiers that
rely on our sentiment tagging features outperform those that do not. The best
model achieves a very promising F1 score of 0.78 and an accuracy of 0.80.


title:
Strategies for Searching Video Content with Text Queries or Video
  Examples

abstract:
  The large number of user-generated videos uploaded on to the Internet
everyday has led to many commercial video search engines, which mainly rely on
text metadata for search. However, metadata is often lacking for user-generated
videos, thus these videos are unsearchable by current search engines.
Therefore, content-based video retrieval (CBVR) tackles this metadata-scarcity
problem by directly analyzing the visual and audio streams of each video. CBVR
encompasses multiple research topics, including low-level feature design,
feature fusion, semantic detector training and video search/reranking. We
present novel strategies in these topics to enhance CBVR in both accuracy and
speed under different query inputs, including pure textual queries and query by
video examples. Our proposed strategies have been incorporated into our
submission for the TRECVID 2014 Multimedia Event Detection evaluation, where
our system outperformed other submissions in both text queries and video
example queries, thus demonstrating the effectiveness of our proposed
approaches.


title:
Improving Agreement and Disagreement Identification in Online
  Discussions with A Socially-Tuned Sentiment Lexicon

abstract:
  We study the problem of agreement and disagreement detection in online
discussions. An isotonic Conditional Random Fields (isotonic CRF) based
sequential model is proposed to make predictions on sentence- or segment-level.
We automatically construct a socially-tuned lexicon that is bootstrapped from
existing general-purpose sentiment lexicons to further improve the performance.
We evaluate our agreement and disagreement tagging model on two disparate
online discussion corpora -- Wikipedia Talk pages and online debates. Our model
is shown to outperform the state-of-the-art approaches in both datasets. For
example, the isotonic CRF model achieves F1 scores of 0.74 and 0.67 for
agreement and disagreement detection, when a linear chain CRF obtains 0.58 and
0.56 for the discussions on Wikipedia Talk pages.


title: Optical absorbers based on strong interference in ultra-thin films

abstract:
  Optical absorbers find uses in a wide array of applications across the
electromagnetic spectrum, including photovoltaic and photochemical cells,
photodetectors, optical filters, stealth technology, and thermal light sources.
Recent efforts have sought to reduce the footprint of optical absorbers,
conventionally based on graded structures or Fabry-Perot-type cavities, by
using the emerging concepts of plasmonics, metamaterials, and metasurfaces.
Unfortunately, these new absorber designs require patterning on subwavelength
length scales, and are therefore impractical for many large-scale optical and
optoelectronic devices.
  In this article, we summarize recent progress in the development of optical
absorbers based on lossy films with thicknesses significantly smaller than the
incident optical wavelength. These structures have a small footprint and
require no nanoscale patterning. We outline the theoretical foundation of these
absorbers based on "ultra-thin-film interference", including the concepts of
loss-induced phase shifts and critical coupling, and then present several
applications, including ultra-thin color coatings, decorative photovoltaics,
high-efficiency photochemical cells, and infrared scene generators.


title: View-Driven Deduplication with Active Learning

abstract:
  Visual analytics systems such as Tableau are increasingly popular for
interactive data exploration. These tools, however, do not currently assist
users with detecting or resolving potential data quality problems including the
well-known deduplication problem. Recent approaches for deduplication focus on
cleaning entire datasets and commonly require hundreds to thousands of user
labels. In this paper, we address the problem of deduplication in the context
of visual data analytics. We present a new approach for record deduplication
that strives to produce the cleanest view possible with a limited budget for
data labeling. The key idea behind our approach is to consider the impact that
individual tuples have on a visualization and to monitor how the view changes
during cleaning. With experiments on nine different visualizations for two
real-world datasets, we show that our approach produces significantly cleaner
views for small labeling budgets than state-of-the-art alternatives and that it
also stops the cleaning process after requesting fewer labels.


title:
Quantitative Volume Space From Rigidity with lower Ricci curvature bound
  II

abstract:
  This is the second paper of two in a series under the same title ([CRX]);
both study the quantitative volume space form rigidity conjecture: a closed
$n$-manifold of Ricci curvature at least $(n-1)H$, $H=\pm 1$ or $0$ is
diffeomorphic to a $H$-space form if for every ball of definite size on $M$,
the lifting ball on the Riemannian universal covering space of the ball
achieves an almost maximal volume, provided the diameter of $M$ is bounded for
$H\ne 1$.
  In [CRX], we verified the conjecture for the case that $M$ or its Riemannian
universal covering space $\tilde M$ is not collapsed for $H=1$ or $H\ne 1$
respectively. In the present paper, we will verify this conjecture for the case
that Ricci curvature is also bounded above, while the above non-collapsing
condition is not required.


title:
A Novel Projected Two Binary Variables Formulation for Unit Commitment
  Problem

abstract:
  The thermal unit commitment (UC) problem often can be formulated as a mixed
integer quadratic programming (MIQP), which is difficult to solve efficiently,
especially for large-scale instances. In this paper, with projecting unit
generation level onto [0,1] and reformulation techniques, a novel two binary
(2-bin) variables MIQP formulation for UC problem is presented. We show that
2-bin formulation is more compact than the state-of-the-art one binary (1-bin)
variable formulation and three binary (3-bin) variables formulation. Moreover,
2-bin formulation is tighter than 1-bin and 3-bin formulations in quadratic
cost function, and it is tighter than 1-bin formulation in linear constraints.
Three mixed integer linear programming (MILP) formulations can be obtained from
three UC MIQPs by replacing the quadratic terms in the objective functions by a
sequence of piece-wise perspective-cuts. 2-bin MILP is also the best one due to
the similar reasons of MIQP. The simulation results for realistic instances
that range in size from 10 to 200 units over a scheduling period of 24 hours
show that the proposed 2-bin formulations are competitive with currently
state-of-the-art formulations and promising for large-scale UC problems.


title:
Exact monochromatic finite power beam solutions of Maxwells equations in
  vacuum

abstract:
  We derived and discussed new exact, monochromatic, finite-power, beam-like
solutions of Maxwells equations in vacuum. We derived energy density flux,
total power of the solution, and compared its effective beam area with that of
the Gaussian beam solution.


title:
Chiral Majorana edge state in a quantum anomalous Hall
  insulator-superconductor structure

abstract:
  After the recognition of the possibility to implement Majorana fermions using
the building blocks of solid-state matters, the detection of this peculiar
particle has been an intense focus of research. Here we experimentally
demonstrate a collection of Majorana fermions living in a one-dimensional
transport channel at the boundary of a superconducting quantum anomalous Hall
insulator thin film. A series of topological phase changes are controlled by
the reversal of the magnetization, where a half-integer quantized conductance
plateau (0.5e2/h) is observed as a clear signature of the Majorana phase. This
transport signature can be well repeated during many magnetic reversal sweeps,
and can be tracked at different temperatures, providing a promising evidence of
the chiral Majorana edge modes in the system.

categories: cond-mat.supr-con cond-mat.mes-hall cond-mat.mtrl-sci cond-mat.str-el


title:
The VIRUS-P Exploration of Nearby Galaxies (VENGA): Spatially Resolved
  Gas-Phase Metallicity Distributions in Barred and Unbarred Spirals

abstract:
  We present a study of the excitation conditions and metallicity of ionized
gas (Z_gas) in eight nearby barred and unbarred spiral galaxies from the
VIRUS-P Exploration of Nearby Galaxies (VENGA) survey, which provides high
spatial sampling and resolution (median ~ 387 pc), large coverage from the
bulge to outer disc, broad wavelength range (3600-6800 Ang.), and medium
spectral resolution (~ 120 km s^-1 at 5000 Ang.). Our results are: (1) We
present high resolution gas excitation maps to differentiate between regions
with excitation typical of Seyfert, LINER, or recent star formation. We find
LINER-type excitation at large distances (3-10 kpc) from the centre, and
associate this excitation with diffuse ionized gas (DIG). (2) After excluding
spaxels dominated by Seyfert, LINER, or DIG, we produce maps with the best
spatial resolution and sampling to date of the ionization parameter q, star
formation rate, and Z_gas using common strong line diagnostics. We find that
isolated barred and unbarred spirals exhibit similarly shallow Z_gas profiles
from the inner kpc out to large radii (7-10 kpc or 0.5-1.0 R_25). This implies
that if profiles had steeper gradients at earlier epochs, then the present-day
bar is not the primary driver flattening gradients over time. This result
contradicts earlier claims, but agrees with recent IFU studies. (3) The Z_gas
gradients in our z ~ 0 massive spirals are markedly shallower, by ~ 0.2 dex
kpc^-1, than published gradients for lensed lower mass galaxies at z ~ 1.5-2.0.
Cosmologically-motivated hydrodynamical simulations best match this inferred
evolution, but the match is sensitive to adopted stellar feedback
prescriptions.


title:
Ionization of protoplanetary disks by galactic cosmic rays, solar
  protons, and by supernova remnants

abstract:
  Galactic cosmic rays and solar protons ionize the present terrestrial
atmosphere, and the air showers are simulated by well-tested Monte-Carlo
simulations, such as PHITS code. We use the latest version of PHITS to evaluate
the possible ionization of protoplanetary disks by galactic cosmic rays (GCRs),
solar protons, and by supernova remnants. The attenuation length of GCR
ionization is updated as 118 g cm-2, which is approximately 20% larger than the
popular value. Hard and soft possible spectra of solar protons give comparable
and 20% smaller attenuation lengths compared with those from standard GCR
spectra, respectively, while the attenuation length is approximately 10% larger
for supernova remnants. Further, all of the attenuation lengths become 10%
larger in the compound gas of cosmic abundance, e.g. 128 g cm-2 for GCRs, which
can affect the minimum estimate of the size of dead zones in protoplanetary
disks when the incident flux is unusually high.


title: Orbits of antichains in certain root posets

abstract:
  This paper gives another proof of Propp and Roby's theorem saying that the
average antichain size in any reverse operator orbit of the poset $[m]\times
[n]$ is $\frac{mn}{m+n}$. It is conceivable that our method should work for
other situations. As a demonstration, we show that the average size of
antichains in any reverse operator orbit of $[m]\times K_{n-1}$ equals
$\frac{2mn}{m+2n-1}$. Here $K_{n-1}$ is the minuscule poset $[n-1]\oplus ([1]
\sqcup [1]) \oplus [n-1]$. Note that $[m]\times [n]$ and $[m]\times K_{n-1}$
can be interpreted as sub-families of certain root posets. We guess these root
posets should provide a unified setting to exhibit the homomesy phenomenon
defined by Propp and Roby.


abstract:
  In this paper, we develop Hamiltonian particle-in-cell methods for
Vlasov-Maxwell equations by applying conforming finite element methods in space
and splitting methods in time. For the spatial discretisation, the criteria for
choosing finite element spaces are presented such that the semi-discrete system
possesses a discrete non-canonical Poisson structure. We apply a Hamiltonian
splitting method to the semi-discrete system in time, then the resulting
algorithm is Poisson preserving and explicit. The conservative properties of
the algorithm guarantee the efficient and accurate numerical simulation of the
Vlasov-Maxwell equations over long-time.


title:
Genuinely quantum effects in nonlinear spectroscopy: vacuum fluctuations
  and their induced superradiance

abstract:
  The classical or quantum nature of optical spectroscopy signals is a topic
that has attracted great attention recently. Spectroscopic techniques have been
classified as quantum or classical depending on the light-source used in their
implementations. In this way, experiments performed with quantum light---such
as entangled photon pairs---have been labeled as quantum spectroscopies,
whereas those performed with coherent laser pulses are generally referred to as
classical ones. In this work, we highlight the fact that typical
laser-spectroscopy signals should sometimes be deemed quantum too, as they
contain information about the quantum vacua of the modes that interact with the
sample. Using a minimalistic model, namely frequency-integrated pump-probe
spectroscopy, we demonstrate that vacuum contributions can be expressed as a
correction term to the \emph{classical} pump-probe signals, which scales
linearly with the intensity of the pump field. Remarkably, we show that these
vacuum contributions may not be negligible and lead to the observation of
superradiance in pump-probe experiments, provided that fields interacting with
the medium are arranged in a collinear configuration.

categories: quant-ph cond-mat.soft physics.atom-ph physics.chem-ph


title: Deep Learning for Identifying Metastatic Breast Cancer

abstract:
  The International Symposium on Biomedical Imaging (ISBI) held a grand
challenge to evaluate computational systems for the automated detection of
metastatic breast cancer in whole slide images of sentinel lymph node biopsies.
Our team won both competitions in the grand challenge, obtaining an area under
the receiver operating curve (AUC) of 0.925 for the task of whole slide image
classification and a score of 0.7051 for the tumor localization task. A
pathologist independently reviewed the same images, obtaining a whole slide
image classification AUC of 0.966 and a tumor localization score of 0.733.
Combining our deep learning system's predictions with the human pathologist's
diagnoses increased the pathologist's AUC to 0.995, representing an
approximately 85 percent reduction in human error rate. These results
demonstrate the power of using deep learning to produce significant
improvements in the accuracy of pathological diagnoses.


title: The Kalman Decomposition for Linear Quantum Systems

abstract:
  This paper studies the Kalman decomposition for linear quantum systems.
Contrary to the classical case, the coordinate transformation used for the
decomposition must belong to a specific class of transformations as a
consequence of the laws of quantum mechanics. We propose a construction method
for such transformations that put the system in a Kalman canonical form.
Furthermore, we uncover an interesting structure for the obtained
decomposition. In the case of passive systems, it is shown that there exist
only controllable/observable and uncontrollable/unobservable subsystems. In the
general case, controllable/unobservable and uncontrollable/observable
subsystems may also be present, but their respective system variables must be
conjugate variables of each other. This decomposition naturally exposes
decoherence-free modes, quantum-nondemolition modes, quantum-mechanics-free
subsystems, and back-action evasion measurements in the quantum system, which
are useful resources for quantum information processing, and quantum
measurements. The theory developed is applied to physical examples.


title:
Capacity of Continuous-Space Electromagnetic Channels with Lossy
  Transceiver

abstract:
  In this paper, the capacity of continuous-space electromagnetic channels,
where transceivers are confined in given lossy regions, is analyzed. First of
all, the regions confining the transceivers are assumed to be filled with
dielectric, which is either lossy or lossless. Then, for capacity analysis, we
use the exact power consumption that takes into account the electromagnetic
interaction between the field and the source. In addition, the exact noise
model followed from the fluctuation-dissipation theorem in thermodynamics is
used at the receive side. The contribution of our work is summarized as
follows. First, we characterize the channel capacity as a function of the size
and the physical property of the regions confining the transceivers and
analytically show how the radiation efficiency affects the capacity. We also
show that the outgoing channel at the transmit side and the incoming channel at
the receive side are information-theoretically equivalent, and thus, the
capacities of both channels are the same. Additionally, the quality factor,
which is inversely proportional to the bandwidth, is theoretically derived, and
the relationship between the spatial degrees of freedom of the channel and the
quality factor is analyzed. Besides, we consider how the power consumption is
affected by the backscattered waves and compare the recent experimental
demonstration with our work by solving the gain-optimization problem with the
constraint on the quality factor.


title:
Measurement-induced state transitions in a superconducting qubit: Beyond
  the rotating wave approximation

abstract:
  Many superconducting qubit systems use the dispersive interaction between the
qubit and a coupled harmonic resonator to perform quantum state measurement.
Previous works have found that such measurements can induce state transitions
in the qubit if the number of photons in the resonator is too high. We
investigate these transitions and find that they can push the qubit out of the
two-level subspace, and that they show resonant behavior as a function of
photon number. We develop a theory for these observations based on level
crossings within the Jaynes-Cummings ladder, with transitions mediated by terms
in the Hamiltonian that are typically ignored by the rotating wave
approximation. We find that the most important of these terms comes from an
unexpected broken symmetry in the qubit potential. We confirm the theory by
measuring the photon occupation of the resonator when transitions occur while
varying the detuning between the qubit and resonator.


title:
Multiple harmonic sums and multiple harmonic star sums are (nearly)
  never integers

abstract:
  It is well known that the harmonic sum $H_n(1)=\sum_{k=1}^n\frac{1}{k}$ is
never an integer for $n>1$. In 1946, Erd\H{o}s and Niven proved that the nested
multiple harmonic sum $H_n(\{1\}^r)=\sum_{1\le k_1<\dots<k_r\le
n}\frac{1}{k_1\cdots k_r}$ can take integer values only for a finite number of
positive integers $n$. In 2012, Chen and Tang refined this result by showing
that $H_n(\{1\}^r)$ is an integer only for $(n,r)=(1,1)$ and $(n,r)=(3,2)$. In
this paper, we consider the integrality problem for arbitrary multiple harmonic
and multiple harmonic star sums and show that none of these sums is an integer
with some natural exceptions like those mentioned above.


title:
Temperature and magnetic field dependence of the internal and lattice
  structures of skyrmions by off-axis electron holography

abstract:
  The internal and lattice structures of magnetic skyrmions in B20-type FeGe
are investigated using off-axis electron holography. The temperature, magnetic
field and angular dependence of the magnetic moments of individual skyrmions
are analyzed. Whereas the internal skyrmion shape is found to vary with
magnetic field, the inter-skyrmion distance remains almost unchanged in the
lattice phase. The amplitude of the local magnetic moment is found to depend on
temperature, while the skyrmion shape does not. Deviations from a circular to a
hexagonal skyrmion structure are observed in the lattice phase.


title: A Compact Index for Order-Preserving Pattern Matching

abstract:
  Order-preserving pattern matching was introduced recently but it has already
attracted much attention. Given a reference sequence and a pattern, we want to
locate all substrings of the reference sequence whose elements have the same
relative order as the pattern elements. For this problem we consider the
offline version in which we build an index for the reference sequence so that
subsequent searches can be completed very efficiently. We propose a
space-efficient index that works well in practice despite its lack of good
worst-case time bounds. Our solution is based on the new approach of
decomposing the indexed sequence into an order component, containing ordering
information, and a delta component, containing information on the absolute
values. Experiments show that this approach is viable, faster than the
available alternatives, and it is the first one offering simultaneously small
space usage and fast retrieval.


title:
An Efficient Large-scale Semi-supervised Multi-label Classifier Capable
  of Handling Missing labels

abstract:
  Multi-label classification has received considerable interest in recent
years. Multi-label classifiers have to address many problems including:
handling large-scale datasets with many instances and a large set of labels,
compensating missing label assignments in the training set, considering
correlations between labels, as well as exploiting unlabeled data to improve
prediction performance. To tackle datasets with a large set of labels,
embedding-based methods have been proposed which seek to represent the label
assignments in a low-dimensional space. Many state-of-the-art embedding-based
methods use a linear dimensionality reduction to represent the label
assignments in a low-dimensional space. However, by doing so, these methods
actually neglect the tail labels - labels that are infrequently assigned to
instances. We propose an embedding-based method that non-linearly embeds the
label vectors using an stochastic approach, thereby predicting the tail labels
more accurately. Moreover, the proposed method have excellent mechanisms for
handling missing labels, dealing with large-scale datasets, as well as
exploiting unlabeled data. With the best of our knowledge, our proposed method
is the first multi-label classifier that simultaneously addresses all of the
mentioned challenges. Experiments on real-world datasets show that our method
outperforms stateof-the-art multi-label classifiers by a large margin, in terms
of prediction performance, as well as training time.


title: Hamiltonians arising from L-functions in the Selberg class

abstract:
  We establish a new equivalent condition for the Grand Riemann Hypothesis for
L-functions in a wide subclass of the Selberg class in terms of canonical
systems of differential equations. A canonical system is determined by a real
symmetric matrixvalued function called a Hamiltonian. To establish the
equivalent condition, we use an inverse problem for canonical systems of a
special type.


title:
Potential thermoelectric material $\mathrm{Cs_2[PdCl_4]I_2}$: a
  first-principles study

abstract:
  The electronic structures and thermoelectric properties of
$\mathrm{Cs_2[PdCl_4]I_2}$ are investigated by the first-principles
calculations and semiclassical Boltzmann transport theory. Both electron and
phonon transport are considered to attain the figure of merit $ZT$. A modified
Becke and Johnson (mBJ) exchange potential, including spin-orbit coupling
(SOC), is employed to investigate electronic part of
$\mathrm{Cs_2[PdCl_4]I_2}$. It is found that SOC has obvious effect on valence
bands, producing huge spin-orbital splitting, which leads to remarkable
detrimental effect on p-type power factor. However, SOC has a negligible
influence on conduction bands, so the n-type power factor hardly change. The
temperature dependence of lattice thermal conductivity by assuming an inverse
temperature dependence is attained from reported ultralow lattice thermal
conductivity of 0.31 $\mathrm{W m^{-1} K^{-1}}$ at room temperature.
Calculating scattering time $\tau$ is challenging, but a hypothetical $\tau$
can be adopted to estimate thermoelectric conversion efficiency. The maximal
figure of merit $ZT$ is up to about 0.70 and 0.60 with scattering time
$\tau$=$10^{-14}$ s and $\tau$=$10^{-15}$ s, respectively. These results make
us believe that $\mathrm{Cs_2[PdCl_4]I_2}$ may be a potential thermoelectric
material.


title:
Fine structure of the exciton electroabsorption in semiconductor
  superlattices

abstract:
  Wannier-Mott excitons in a semiconductor layered superlattice (SL) of period
much smaller than the 2D exciton Bohr radius in the presence of a longitudinal
external dc electric field directed parallel to the SL axis are investigated
analytically. The exciton states and the optical absorption coefficient are
derived in the tight-binding and adiabatic approximations. Strong and weak
electric fields providing spatially localized and extended electron and hole
states, respectively, are studied. The dependencies of the exciton states and
the exciton absorption spectrum on the SL parameters and the electric field
strength are presented in an explicit form. We focus on the fine structure of
the ground quasi-2D exciton level formed by the series of closely spaced energy
levels adjacent for higher frequencies. These levels are related to the
adiabatically slow relative exciton longitudinal motion governed by the
potential formed by the in-plane exciton state. It is shown that the external
electric fields compress the fine structure energy levels, decrease the
intensities of the corresponding optical peaks and increase the exciton binding
energy. A possible experimental study of the fine structure of the exciton
electroabsorption is discussed.


title: RRV: A Spatiotemporal Descriptor for Rigid Body Motion Recognition

abstract:
  Motion behaviors of a rigid body can be characterized by a 6-dimensional
motion trajectory, which contains position vectors of a reference point on the
rigid body and rotations of this rigid body over time. This paper devises a
Rotation and Relative Velocity (RRV) descriptor by exploring the local
translational and rotational invariants of motion trajectories of rigid bodies,
which is insensitive to noise, invariant to rigid transformation and scaling. A
flexible metric is also introduced to measure the distance between two RRV
descriptors. The RRV descriptor is then applied to characterize motions of a
human body skeleton modeled as articulated interconnections of multiple rigid
bodies. To illustrate the descriptive ability of the RRV descriptor, we explore
it for different rigid body motion recognition tasks. The experimental results
on benchmark datasets demonstrate that this simple RRV descriptor outperforms
the previous ones regarding recognition accuracy without increasing
computational cost.


title: A Comparison of Methods for Cascade Prediction

abstract:
  Information cascades exist in a wide variety of platforms on Internet. A very
important real-world problem is to identify which information cascades can go
viral. A system addressing this problem can be used in a variety of
applications including public health, marketing and counter-terrorism. As a
cascade can be considered as compound of the social network and the time
series. However, in related literature where methods for solving the cascade
prediction problem were proposed, the experimental settings were often limited
to only a single metric for a specific problem formulation. Moreover, little
attention was paid to the run time of those methods. In this paper, we first
formulate the cascade prediction problem as both classification and regression.
Then we compare three categories of cascade prediction methods: centrality
based, feature based and point process based. We carry out the comparison
through evaluation of the methods by both accuracy metrics and run time. The
results show that feature based methods can outperform others in terms of
prediction accuracy but suffer from heavy overhead especially for large
datasets. While point process based methods can also run into issue of long run
time when the model can not well adapt to the data. This paper seeks to address
issues in order to allow developers of systems for social network analysis to
select the most appropriate method for predicting viral information cascades.


title: Aerotaxis in the Closest Relatives of Animals

abstract:
  As the closest unicellular relatives of animals, choanoflagellates serve as
useful model organisms for understanding the evolution of animal
multicellularity. An important factor in animal evolution was the increasing
ocean oxygen levels in the Precambrian, which are thought to have influenced
the emergence of complex multicellular life. As a first step in addressing
these conditions, we study here the response of the colony-forming
choanoflagellate $Salpingoeca~rosetta$ to oxygen gradients. Using a
microfluidic device that allows spatio-temporal variations in oxygen
concentrations, we report the discovery that $S.~rosetta$ display positive
aerotaxis. Analysis of the spatial population distributions provides evidence
for logarithmic sensing of oxygen, which enhances sensing in low oxygen
neighborhoods. Analysis of search strategy models on the experimental colony
trajectories finds that choanoflagellate aerotaxis is consistent with
stochastic navigation, the statistics of which are captured using an effective
continuous version based on classical run-and-tumble chemotaxis.


title: How to Fake Multiply by a Gaussian Matrix

abstract:
  Have you ever wanted to multiply an $n \times d$ matrix $X$, with $n \gg d$,
on the left by an $m \times n$ matrix $\tilde G$ of i.i.d. Gaussian random
variables, but could not afford to do it because it was too slow? In this work
we propose a new randomized $m \times n$ matrix $T$, for which one can compute
$T \cdot X$ in only $O(\text{nnz}(X)) + \tilde O(m^2 \cdot d^{3})$ time, for
which the total variation distance between the distributions $T \cdot X$ and
$\tilde G \cdot X$ is as small as desired, i.e., less than any positive
constant. Here $\text{nnz}(X)$ denotes the number of non-zero entries of $X$.
Assuming $\text{nnz}(X) \gg m^2 \cdot d^{3}$, this is a significant savings
over the na\"ive $O(\text{nnz}(X) m)$ time to compute $\tilde G \cdot X$.
Moreover, since the total variation distance is small, we can provably use $T
\cdot X$ in place of $\tilde G \cdot X$ in any application and have the same
guarantees as if we were using $\tilde G \cdot X$, up to a small positive
constant in error probability. We apply this transform to nonnegative matrix
factorization (NMF) and support vector machines (SVM).


title:
The application of the weak electric field pulse to measure the
  pseudo-Stark split by the photon echo beating

abstract:
  A novel scheme for determining the pseudo-Stark splitting of optical lines
has been suggested and tested in experiment. The scheme allows one to observe
the beating of a photon echo waveform under conditions of overlap in time
between a weak electric pulse and its echo- pulse. The pseudo-Stark splitting
is equal to the inverse average modulation period of the echo waveform. The
photon echo beating of the R1-line in Ruby has been observed. The dependence of
the inverse average modulation period of the echo waveform on the average value
of the electric field over the optically excited volume has been found. The
obtained values of the pseudo-Stark parameter are in good agreement with known
literature data.


title: Modeling glacial flow on and onto Pluto's Sputnik Planitia

abstract:
  Observations of Pluto's surface made by the New Horizons spacecraft indicates
present-day nitrogen ice glaciation in and around the basin known as Sputnik
Planum. Motivated by these observations, we have developed an evolutionary
glacial flow model of solid nitrogen ice taking into account its published
thermophysical and rheologies properties. This model assumes that glacial ice
layers flow laminarly and have low aspect ratios which permits a vertically
integrated mathematical formulation. We assess the conditions for the validity
of laminar nitrogen ice motion by revisiting the problem of the onset of
solid-state buoyant convection of nitrogen ice for a variety of bottom thermal
boundary conditions. Subject to uncertainties in nitrogen ice rheology,
nitrogen ice layers are estimated to flow laminarly for thicknesses less than
400-1000 meters. The resulting mass-flux formulation for when the nitrogen ice
flows as a laminar dry glacier is characterized by an Arrhenius-Glen functional
form. The flow model developed is used here to qualitatively answer some
questions motivated by observed glacial flow features found on Sputnik Planum.
We find that the wavy transverse dark features found along the northern
shoreline of Sputnik Planum may be a transitory imprint of shallow topography
just beneath the ice surface suggesting the possibility that a major shoreward
flow event happened relatively recently within the last few hundred years.
Model results also support the interpretation that the prominent darkened
features resembling flow lobes observed along the eastern shoreline of the
Sputnik Planum basin may be a result of wet nitrogen glacial ice flowing into
the basin from the pitted highlands of eastern Tombaugh Regio.


title:
A Comparative Analysis of classification data mining techniques :
  Deriving key factors useful for predicting students performance

abstract:
  Students opting for Engineering as their discipline is increasing rapidly.
But due to various factors and inappropriate primary education in India,
failure rates are high. Students are unable to excel in core engineering
because of complex and mathematical subjects. Hence, they fail in such
subjects. With the help of data mining techniques, we can predict the
performance of students in terms of grades and failure in subjects. This paper
performs a comparative analysis of various classification techniques, such as
Na\"ive Bayes, LibSVM, J48, Random Forest, and JRip and tries to choose best
among these. Based on the results obtained, we found that Na\"ive Bayes is the
most accurate method in terms of students failure prediction and JRip is most
accurate in terms of students grade prediction. We also found that JRip
marginally differs from Na\"ive Bayes in terms of accuracy for students failure
prediction and gives us a set of rules from which we derive the key factors
influencing students performance. Finally, we suggest various ways to mitigate
these factors. This study is limited to Indian Education system scenarios.
However, the factors found can be helpful in other scenarios as well.


title: Absolutely minimum attaining closed operators

abstract:
  We define and discuss properties of the class of unbounded operators which
attain minimum modulus. We establish a relationship between this class and the
class of norm attaining bounded operators and compare the properties of both.
Also we define absolutely minimum attaining operators (possibly unbounded) and
characterize injective absolutely minimum attaining operators as those with
compact generalized inverse. We give several consequences, one of them is that
every such operator has a non trivial hyperinvariant subspace.


title: Equilibrium distributions in entropy driven balanced processes

abstract:
  For entropy driven balanced processes we obtain final states with Poisson,
Bernoulli, negative binomial and P\'olya distributions. We apply this both for
complex networks and particle production. For random networks we follow the
evolution of the degree distribution, $P_n$, in a system where a node can
activate $k$ fixed connections from $K$ possible partnerships among all nodes.
The total number of connections, $N$, is also fixed. For particle physics
problems $P_n$ is the probability of having $n$ particles (or other quanta)
distributed among $k$ states (phase space cells) while altogether a fixed
number of $N$ particles reside on $K$ states.


title:
Absence of superconductivity in ultra-thin layers of FeSe synthesized on
  a topological insulator

abstract:
  The structural and electronic properties of FeSe ultra-thin layers on
Bi$_{2}$Se$_{3}$ have been investigated with a combination of scanning
tunneling microscopy and spectroscopy and angle-resolved photoemission
spectroscopy. The FeSe multi-layers, which are predominantly 3-5 monolayers
(ML) thick, exhibit a hole pocket-like electron band at \bar{\Gamma} and a
dumbbell-like feature at \bar{M}, similar to multi-layers of FeSe on
SrTiO$_{3}$. Moreover, the topological state of the Bi2Se3 is preserved beneath
the FeSe layer, as indicated by a heavily \it{n}-doped Dirac cone. Low
temperature STS does not exhibit a superconducting gap for any investigated
thickness down to a temperature of 5 K.


title:
A 2D Acceptance Diagram Description of Neutron Primary Spectrometer
  Beams

abstract:
  Many types of neutron spectrometer use a conventional primary spectrometer
consisting of some collimator, a crystal monochromator and a second collimator.
Conventional resolution descriptions use instrument parameter values to deduce
the beam character and thence the instrument transmission and resolution. This
article solves the inverse problem of choosing beam elements to deliver some
desired beam character and shows that there are many possible choices of
elements to deliver any given beam character. Dealing with this multiplicity
seems to be a central issue in the search for optimal instrument designs
especially if using numerical methods. The particular approach adopted here is
to extend the 2D "Acceptance Diagram" view of the in-scattering-plane component
of primary spectrometer beams to include horizontally curved monochromators and
a variety of collimator types (beamtubes, guides, Soller collimators and radial
Soller collimators). This visual approach clarifies the effect of primary
spectrometer variables on the sample position beam and suggests a novel
mechanically simple primary spectrometer design offering great flexibility
coupled with maximised transmission.


title:
Correction of Blurring due to a Difference in Scanning Direction of
  Field-Free Line in Projection-Based Magnetic Particle Imaging

abstract:
  In projection-based magnetic particle imaging (MPI) with a field-free-line
(FFL) encoding scheme, projection data are usually acquired by moving the FFL
in a zigzag and a difference in the projection data occurs depending on the
scanning direction of FFL, resulting in blurring in the reconstructed images.
In this study, we developed a method for correcting the blur by deconvolution
using a signal-delay constant ({\xi}). The {\xi} value for correction ({\xi}c)
was determined by acquiring projection data in positive and negative directions
and searching for the {\xi} value which minimized the 2-norm between the
deconvolved projection data in the two directions. We validated our method
using a line and A-shaped phantoms for various velocities of FFL (vFFL). The
{\xi}c value correlated linearly with vFFL. The full width at half maximum of
the line phantom decreased significantly after correction of the blur. The
effectiveness of our method was also confirmed by the MPI images of the
A-shaped phantom. These results suggest that our method will be useful for
enhancing the reliability of projection-based MPI.


title:
Connecting web-based mapping services with scientific data repositories:
  collaborative curation and retrieval of simulation data via a geospatial
  interface

abstract:
  Increasing quantities of scientific data are becoming readily accessible via
online repositories such as those provided by Figshare and Zenodo.
Geoscientific simulations in particular generate large quantities of data, with
several research groups studying many, often overlapping areas of the world.
When studying a particular area, being able to keep track of one's own
simulations as well as those of collaborators can be challenging. This paper
describes the design, implementation, and evaluation of a new tool for visually
cataloguing and retrieving data associated with a given geographical location
through a web-based Google Maps interface. Each data repository is pin-pointed
on the map with a marker based on the geographical location that the dataset
corresponds to. By clicking on the markers, users can quickly inspect the
metadata of the repositories and download the associated data files. The crux
of the approach lies in the ability to easily query and retrieve data from
multiple sources via a common interface. While many advances are being made in
terms of scientific data repositories, the development of this new tool has
uncovered several issues and limitations of the current state-of-the-art which
are discussed herein, along with some ideas for the future.


title:
The influence of surfactants on thermocapillary flow instabilities in
  low Prandtl melting pools

abstract:
  Flows in low Prandtl number liquid pools are relevant for various technical
applications, and have so far only been investigated for the case of pure
fluids, i.e. with a constant, negative surface tension temperature coefficient
$\partial\gamma/\partial T$. Real-world fluids containing surfactants have a
temperature dependent $\partial\gamma/\partial T > 0$, which may change sign to
$\partial\gamma/\partial T < 0$ at a critical temperature $T_c$. Where
thermocapillary forces are the main driving force, this can have a tremendous
effect on the resulting flow patterns and the associated heat transfer.
  Here we investigate the stability of such flows for five Marangoni numbers in
the range of $2.1\times 10^6 \leq Ma \leq 3.4\times 10^7$ using dynamic large
eddy simulations (LES), which we validate against a high resolution direct
numerical simulation (DNS). We find that the five cases span all flow regimes,
i.e. stable laminar flow at $Ma \leq 2.1\times 10^6$, transitional flow with
rotational instabilities at $Ma = 2.8\times 10^6$ and $Ma = 4.6\times 10^6$ and
turbulent flow at $Ma = 1.8\times 10^7$ and $Ma = 3.4\times 10^7$.


title:
AMPF: Application-aware Multipath Packet Forwarding using Machine
  Learning and SDN

abstract:
  This paper proposes an application-aware multipath packet forwarding
framework that integrates Machine Learning Techniques (MLT) and Software
Defined Networks (SDN). As the Internet provides a variety of services and
their performance requirement has become heterogeneous, it is common to come
across the scenario of multiple flows competing for a constrained resource such
as bandwidth, less jitter or low latency path. Such factors are application
specific requirement that is beyond the knowledge of a simple combination of
protocol type and port number. Better overall performance could be achieved if
the network is able to prioritize the flows and assign resources based on their
application specific requirement. Our system prioritizes each of the flows
using MLT and routes it through a path according to the flow priority and
network state using SDN. The proof of concept implementation has been done on
OpenvSwitch and evaluation results involving a large number of flows exhibited
a significant improvement over the traditional network setup. We also report
that the port number and protocol are not contributing to determine the
application in the decision-making process of Machine Learning (ML).


title:
A geometric instability of the laminar axisymmetric Euler flows with
  oscillating flux

abstract:
  The dynamics along the particle trajectories for the 3D axisymmetric Euler
equations in an infinite cylinder are considered. It is shown that if the
inflow-outflow is highly oscillating in time, the corresponding Euler flow
cannot keep the uniformly smooth laminar profile provided that the swirling
component is not zero. In the proof, Frenet-Serret formulas and orthonormal
moving frame are essentially used.


title:
Soft X-ray Irradiation of Silicates: Implications on Dust Evolution in
  Protoplanetary Disks

abstract:
  The processing of energetic photons on bare silicate grains was simulated
experimentally on silicate films submitted to soft X-rays of energies up to
1.25 keV. The silicate material was prepared by means of a microwave assisted
solgel technique. Its chemical composition reflects the Mg2SiO4 stoichiometry
with residual impurities due to the synthesis method. The experiments were
performed using the spherical grating monochromator beamline at the National
Synchrotron Radiation Research Center in Taiwan. We found that soft X-ray
irradiation induces structural changes that can be interpreted as an
amorphization of the processed silicate material. The present results may have
relevant implications in the evolution of silicate materials in X-ray
irradiated protoplanetary disks.


title: Modelling Requirements for Content Recommendation Systems

abstract:
  This paper addresses the modelling of requirements for a content
Recommendation System (RS) for Online Social Networks (OSNs). On OSNs, a user
switches roles constantly between content generator and content receiver. The
goals and softgoals are different when the user is generating a post, as
opposed as replying to a post. In other words, the user is generating instances
of different entities, depending on the role she has: a generator generates
instances of a "post", while the receiver generates instances of a "reply".
Therefore, we believe that when addressing Requirements Engineering (RE) for
RS, it is necessary to distinguish these roles clearly.
  We aim to model an essential dynamic on OSN, namely that when a user creates
(posts) content, other users can ignore that content, or themselves start
generating new content in reply, or react to the initial posting. This dynamic
is key to designing OSNs, because it influences how active users are, and how
attractive the OSN is for existing, and to new users. We apply a well-known
Goal Oriented RE (GORE) technique, namely i-star, and show that this language
fails to capture this dynamic, and thus cannot be used alone to model the
problem domain. Hence, in order to represent this dynamic, its relationships to
other OSNs' requirements, and to capture all relevant information, we suggest
using another modelling language, namely Petri Nets, on top of i-star for the
modelling of the problem domain. We use Petri Nets because it is a tool that is
used to simulate the dynamic and concurrent activities of a system and can be
used by both practitioners and theoreticians.


title:
Complete Hamiltonian analysis of cosmological perturbations at all
  orders II: Non-canonical scalar field

abstract:
  In this work, we present a consistent Hamiltonian analysis of cosmological
perturbations for generalized non-canonical scalar fields. In order to do so,
we introduce a new phase-space variable that is uniquely defined for different
non-canonical scalar fields. We also show that this is the simplest and
efficient way of expressing the Hamiltonian. We extend the Hamiltonian approach
of [arXiv:1512.02539] to non-canonical scalar field and obtain a new definition
of speed of sound in phase-space. In order to invert generalized phase-space
Hamilton's equations to Euler-Lagrange equations of motion, we prescribe a
general inversion formulae and show that our approach for non-canonical scalar
field is consistent. We also obtain the third and fourth order interaction
Hamiltonian for generalized non-canonical scalar fields and briefly discuss the
extension of our method to generalized Galilean scalar fields.


title:
Gauge transformations and conserved quantities in classical and quantum
  mechanics

abstract:
  We are taught that gauge transformations in classical and quantum mechanics
do not change the physics of the problem. Nevertheless here we discuss three
broad scenarios where under gauge transformations: (i) conservation laws are
not preserved in the usual manner; (ii) non-gauge-invariant quantities can be
associated with physical observables; and (iii) there are changes in the
physical boundary conditions of the wave function that render it
non-single-valued. We give worked examples that illustrate these points, in
contrast to general opinions from classic texts. We also give a historical
perspective on the development of Abelian gauge theory in relation to our
particular points. Our aim is to provide a discussion of these issues at the
graduate level.


title: Device-to-Device Communication in Cellular Networks: A Survey

abstract:
  A constant need to increase the network capacity for meeting the growing
demands of the subscribers has led to the evolution of cellular communication
networks from the first generation (1G) to the fifth generation (5G). There
will be billions of connected devices in the near future. Such a large number
of connections are expected to be heterogeneous in nature, demanding higher
data rates, lesser delays, enhanced system capacity and superior throughput.
The available spectrum resources are limited and need to be flexibly used by
the mobile network operators (MNOs) to cope with the rising demands. An
emerging facilitator of the upcoming high data rate demanding next generation
networks (NGNs) is device-to-device (D2D) communication. An extensive survey on
device-to-device (D2D) communication has been presented in this paper,
including the plus points it offers, the key open issues associated with it
like peer discovery, resource allocation etc, demanding special attention of
the research community, some of its integrant technologies like millimeter wave
D2D (mmWave), ultra dense networks (UDNs), cognitive D2D, handover procedure in
D2D and its numerous use cases. Architecture is suggested aiming to fulfill all
the subscriber demands in an optimal manner. The Appendix mentions some ongoing
standardization activities and research projects of D2D communication.


title: Some Model Theoretic Properties of Non-AC Generic Structures

abstract:
  In the context of Hrushovski constructions we take a language $ \mathcal{L} $
with a ternary relation $ R $ and consider the theory of the generic models $
M^{*}_{\alpha}, $ of the class of finite $ \mathcal{L}$-structures equipped
with predimension functions $ \delta_{\alpha}, $ for $
\alpha\in(0,1]\cap\mathbb{Q} $. The theory of generic structures of non-AC
smooth classes have been investigated from different points of view, including
decidability and their power in interpreting known structures and theories. For
a rational $ \alpha\in(0,1], $ first we prove that the theory of $
M^{*}_{\alpha} $ admits a quantifier elimination down to a meaningful class of
formulas, called \textit{closure formulas}; and on the other hand we prove that
$ Th(M^{*}_{\alpha}) $ does not have the finite model property.


title: Evolution of electron beam pulses of short duration in the solar corona

abstract:
  Narrowband radio bursts with durations of the order of milliseconds, called
spikes, are known to be associated with solar flares. In order to understand
the particle beams responsible for the radio spike phenomena, evolution of
electron beam pulses injected from a solar flare region into the corona is
studied. Numerical integration of the Fokker-Planck (FP) equation is used to
follow the evolution of the electron beam pulse. The simulations show that the
short duration pulses lose most of their energy within a second of propagation
into the corona. Electron beam with a small low energy cut off is thermalised
faster than that with a high low energy cut off.


title: Identifying the Academic Rising Stars

abstract:
  Predicting the fast-rising young researchers (Academic Rising Stars) in the
future provides useful guidance to the research community, e.g., offering
competitive candidates to university for young faculty hiring as they are
expected to have success academic careers. In this work, given a set of young
researchers who have published the first first-author paper recently, we solve
the problem of how to effectively predict the top k% researchers who achieve
the highest citation increment in \Delta t years. We explore a series of
factors that can drive an author to be fast-rising and design a novel impact
increment ranking learning (IIRL) algorithm that leverages those factors to
predict the academic rising stars. Experimental results on the large ArnetMiner
dataset with over 1.7 million authors demonstrate the effectiveness of IIRL.
Specifically, it outperforms all given benchmark methods, with over 8% average
improvement. Further analysis demonstrates that the prediction models for
different research topics follow the similar pattern. We also find that
temporal features are the best indicators for rising stars prediction, while
venue features are less relevant.


title:
A Conceptual Design of Mobile Learning Applications for Preschool
  Children

abstract:
  This article focuses on the possibilities of using mobile learning in the
Bulgarian preschool education of young children. The state preschool
educational regulations are presented and discussed. The problem concerning the
children's safety when using mobile devices in terms of access to information
on the Internet is revealed and analyzed. Two conceptual models of applications
for mobile learning aimed at preschool children are designed. Their advantages
and disadvantages are outlined and discussed. Keywords - mobile applications
for children, mobile learning, design of mobile learning component, software
engineering


title:
$\pi_0$ pole mass calculation in a strong magnetic field and lattice
  constraints

abstract:
  The $\pi_0$ neutral meson pole mass is calculated in a strongly magnetized
medium using the SU(2) Nambu-Jona-Lasinio model within the random phase
approximation (RPA) at zero temperature and zero baryonic density. We employ a
magnetic field dependent coupling, $G(eB)$, fitted to reproduce lattice QCD
results for the quark condensates. Divergent quantities are handled with a
magnetic field independent regularization scheme in order to avoid unphysical
oscillations. A comparison between the running and the fixed couplings reveals
that the former produces results much closer to the predictions from recent
lattice calculations. In particular, we find that the $\pi_0$ meson mass
systematically decreases when the magnetic field increases while the scalar
mass remains almost constant. We also investigate how the magnetic background
influences other mesonic properties such as $f_{{\pi}_0}$ and $g_{\pi_0 q q}$.


title:
On Stability for Impulsive Delay Differential Equations and Application
  to a Periodic Lasota-Wazewska Model

abstract:
  We consider a class of scalar delay differential equations with impulses and
satisfying an Yorke-type condition, for which some criteria for the global
stability of the zero solution are established. Here, the usual requirements
about the impulses are relaxed.
  The results can be applied to study the stability of other solutions, such as
periodic solutions. As an illustration, a very general periodic Lasota-Wazewska
model with impulses and multiple time-dependent delays is addressed, and the
global attractivity of its positive periodic solution analysed.
  Our results are discussed within the context of recent literature.


title:
Suppression of magnetoresistance in thin $WTe_2$ flakes by surface
  oxidation

abstract:
  Recent renewed interest in layered transition metal dichalcogenides stems
from the exotic electronic phases predicted and observed in the single- and
few-layer limit. Realizing these electronic phases requires preserving the
desired transport properties down to a monolayer, which is challenging. Here,
using semimetallic $WTe_2$ that exhibits large magnetoresistance, we show that
surface oxidation and Fermi level pinning degrade the transport properties of
thin $WTe_2$ flakes significantly. With decreasing $WTe_2$ flake thickness, we
observe a dramatic suppression of the large magnetoresistance. This is
explained by fitting a two-band model to the transport data, which shows that
mobility of the electron and hole carriers decreases significantly for thin
flakes. The microscopic origin of this mobility decrease is attributed to a ~ 2
nm-thick amorphous surface oxide layer that introduces disorder. The oxide
layer also shifts the Fermi level by ~ 300 meV at the $WTe_2$ surface. However,
band bending due to this Fermi level shift is not the dominant cause for the
suppression of magnetoresistance as the electron and hole carrier densities are
balanced down to ~ 13 nm based on the two-band model. Our study highlights the
critical need to investigate often unanticipated and sometimes unavoidable
extrinsic surface effects on the transport properties of layered
dichalcogenides and other 2D materials.


title: Singular perturbations with multiple poles of the simple polynomials

abstract:
  In this article, we study the dynamics of the following family of rational
maps with one parameter: \begin{equation*} f_\lambda(z)=
z^n+\frac{\lambda^2}{z^n-\lambda}, \end{equation*} where $n\geq 3$ and
$\lambda\in\mathbb{C}^*$. This family of rational maps can be viewed as a
singular perturbations of the simple polynomial $P_n(z)=z^n$. We give a
characterization of the topological properties of the Julia sets of the family
$f_\lambda$ according to the dynamical behaviors of the orbits of the free
critical points.


title: Spin Transport at Interfaces with Spin-Orbit Coupling: Formalism

abstract:
  We generalize magnetoelectronic circuit theory to account for spin transfer
to and from the atomic lattice via interfacial spin-orbit coupling. This
enables a proper treatment of spin transport at interfaces between a
ferromagnet and a heavy-metal non-magnet. This generalized approach describes
spin transport in terms of drops in spin and charge accumulations across the
interface (as in the standard approach), but additionally includes the
responses from in-plane electric fields and offsets in spin accumulations. A
key finding is that in-plane electric fields give rise to spin accumulations
and spin currents that can be polarized in any direction, generalizing the
Rashba-Edelstein and spin Hall effects. The spin accumulations exert torques on
the magnetization at the interface when they are misaligned from the
magnetization. The additional out-of-plane spin currents exert torques via the
spin-transfer mechanism on the ferromagnetic layer. To account for these
phenomena we also describe spin torques within the generalized circuit theory.
The additional effects included in this generalized circuit theory suggest
modifications in the interpretations of experiments involving spin orbit
torques, spin pumping, spin memory loss, the Rashba-Edelstein effect, and the
spin Hall magnetoresistance.


title:
Egyptian Arabic to English Statistical Machine Translation System for
  NIST OpenMT'2015

abstract:
  The paper describes the Egyptian Arabic-to-English statistical machine
translation (SMT) system that the QCRI-Columbia-NYUAD (QCN) group submitted to
the NIST OpenMT'2015 competition. The competition focused on informal dialectal
Arabic, as used in SMS, chat, and speech. Thus, our efforts focused on
processing and standardizing Arabic, e.g., using tools such as 3arrib and
MADAMIRA. We further trained a phrase-based SMT system using state-of-the-art
features and components such as operation sequence model, class-based language
model, sparse features, neural network joint model, genre-based
hierarchically-interpolated language model, unsupervised transliteration
mining, phrase-table merging, and hypothesis combination. Our system ranked
second on all three genres.


title:
Termination of Single Crystal Bi2Se3 Surfaces Prepared by Various
  Methods

abstract:
  Bismuth Selenide (Bi2Se3) is a topological insulator with a two-dimensional
layered structure that enables clean and well-ordered surfaces to be prepared
by cleaving. Although some studies have demonstrated that the cleaved surface
is terminated with Se, as expected from the bulk crystal structure, other
reports have indicated either a Bi- or mixed-termination. Low energy ion
scattering (LEIS), low energy electron diffraction (LEED) and x-ray
photoelectron spectroscopy (XPS) are used here to compare surfaces prepared by
ex situ cleaving, in situ cleaving, and ion bombardment and annealing (IBA) in
ultra-high vacuum (UHV). Surfaces prepared by in situ cleaving and IBA are well
ordered and Se-terminated. Ex situ cleaved samples could be either
Se-terminated or Bi-rich, are less well ordered and have adsorbed contaminants.
This suggests that a chemical reaction involving atmospheric contaminants,
which may preferentially adsorb at surface defects, could contribute to the
non-reproducibility of the termination.


title: Crosscap Stability

abstract: We provide an alternative proof that Crosscaps are diffeomorphically stable.


title:
The group of $K_1$-zero-cycles on the second generalized Severi-Brauer
  variety of an algebra of index 4

abstract:
  In this manuscript, it is shown that the group of $K_1$-zero-cycles on the
second generalized Severi-Brauer variety of an algebra $A$ of index 4 is given
by elements of the group $K_1(A)$ together with a square-root of their reduced
norm. Utilizing results of Krashen concerning exceptional isomorphisms, we
translate our problem to the computation of cycles on involution varieties.
Work of Chernousov and Merkurjev then gives a means of describing such cycles
in terms of Clifford and spin groups and corresponding $R$-equivalence classes.
We complete our computation by giving an explicit description of these
algebraic groups.


title:
Online and Offline Handwritten Chinese Character Recognition: A
  Comprehensive Study and New Benchmark

abstract:
  Recent deep learning based methods have achieved the state-of-the-art
performance for handwritten Chinese character recognition (HCCR) by learning
discriminative representations directly from raw data. Nevertheless, we believe
that the long-and-well investigated domain-specific knowledge should still help
to boost the performance of HCCR. By integrating the traditional
normalization-cooperated direction-decomposed feature map (directMap) with the
deep convolutional neural network (convNet), we are able to obtain new highest
accuracies for both online and offline HCCR on the ICDAR-2013 competition
database. With this new framework, we can eliminate the needs for data
augmentation and model ensemble, which are widely used in other systems to
achieve their best results. This makes our framework to be efficient and
effective for both training and testing. Furthermore, although
directMap+convNet can achieve the best results and surpass human-level
performance, we show that writer adaptation in this case is still effective. A
new adaptation layer is proposed to reduce the mismatch between training and
test data on a particular source layer. The adaptation process can be
efficiently and effectively implemented in an unsupervised manner. By adding
the adaptation layer into the pre-trained convNet, it can adapt to the new
handwriting styles of particular writers, and the recognition accuracy can be
further improved consistently and significantly. This paper gives an overview
and comparison of recent deep learning based approaches for HCCR, and also sets
new benchmarks for both online and offline HCCR.


title: Probing the shear viscosity of an active nematic

abstract:
  In vitro reconstituted active systems, such as the ATP-driven microtubule
bundle suspension developed by the Dogic group, provide a fertile testing
ground for elucidating the phenomenology of active liquid crystalline states.
Controlling such novel phases of matter crucially depends on our knowledge of
their material and physical properties. In this letter, we show that the
rheological properties of an active nematic film can be probed by varying its
hydrodynamic coupling to a bounding oil layer. Using the motion of
disclinations as intrinsic tracers of the flow field and a hydrodynamic model,
we obtain an estimate for the as of now unknown shear viscosity of the nematic
film. Knowing this now provides us with an additional handle for robust and
precision tunable control of the emergent dynamics of active fluids.


title: Simulation of Deformation and Flow in Fractured, Poroelastic Materials

abstract:
  We introduce a coupled system of PDEs for the modeling of the fluid-fluid and
fluid-solid interaction in a poroelastic material with a single static
fracture. The fluid flow in the fracture is modeled by a lower-dimensional
Darcy equation, which interacts with the surrounding rock matrix and the fluid
it contains. We explicitly allow the fracture to end within the domain, and the
fracture width is an unknown of the problem. The resulting weak problem is
nonlinear, elliptic and symmetric, and can be given the structure of a
fixed-point problem. We show that the coupled fluid-fluid problem has a
solution in a specially crafted Sobolev space, even though the fracture width
cannot be bounded away from zero near the crack tip.
  For numerical simulations, we combine XFEM discretizations for the rock
matrix deformation and pore pressure with a standard lower-dimensional finite
element method for the fracture flow problem. The resulting coupled discrete
system consists of linear subdomain problems coupled by nonlinear coupling
conditions. We solve the coupled system with a substructuring solver and
observe very fast convergence. We also observe optimal mesh dependence of the
discretization errors even in the presence of crack tips.


title: Volume distribution of nodal domains of random band-limited functions

abstract:
  We study the volume distribution of nodal domains of random band-limited
functions on generic manifolds, and find that in the high energy limit a
typical instance obeys a deterministic universal law, independent of the
manifold. Some of the basic qualitative properties of this law, such as its
support, monotonicity and continuity of the cumulative probability function,
are established.


title: On Reward Function for Survival

abstract:
  Obtaining a survival strategy (policy) is one of the fundamental problems of
biological agents. In this paper, we generalize the formulation of previous
research related to the survival of an agent and we formulate the survival
problem as a maximization of the multi-step survival probability in future time
steps. We introduce a method for converting the maximization of multi-step
survival probability into a classical reinforcement learning problem. Using
this conversion, the reward function (negative temporal cost function) is
expressed as the log of the temporal survival probability. And we show that the
objective function of the reinforcement learning in this sense is proportional
to the variational lower bound of the original problem. Finally, We empirically
demonstrate that the agent learns survival behavior by using the reward
function introduced in this paper.