title: Easy-setup eye movement recording system for human-computer interaction

abstract:
  Tracking the movement of human eyes is expected to yield natural and
convenient applications based on human-computer interaction (HCI). To implement
an effective eye-tracking system, eye movements must be recorded without
placing any restriction on the user's behavior or user discomfort. This paper
describes an eye movement recording system that offers free-head, simple
configuration. It does not require the user to wear anything on her head, and
she can move her head freely. Instead of using a computer, the system uses a
visual digital signal processor (DSP) camera to detect the position of eye
corner, the center of pupil and then calculate the eye movement. Evaluation
tests show that the sampling rate of the system can be 300 Hz and the accuracy
is about 1.8 degree/s.


title: Stochastic Thermodynamics of Learning

abstract:
  Virtually every organism gathers information about its noisy environment and
builds models from that data, mostly using neural networks. Here, we use
stochastic thermodynamics to analyse the learning of a classification rule by a
neural network. We show that the information acquired by the network is bounded
by the thermodynamic cost of learning and introduce a learning efficiency
$\eta\le1$. We discuss the conditions for optimal learning and analyse Hebbian
learning in the thermodynamic limit.


title: More on some Mock theta Double sums

abstract:
  We offer some further applications of some Bailey pairs related to some mock
theta functions which were established in a recent study. We discuss and offer
some double-sum $q$-series, with new relationships among mock theta functions.
We also offer a new relationship between the Bailey pair of Bringmann and Kane
with that of Andrews.


title:
Emergence of foveal image sampling from learning to attend in visual
  scenes

abstract:
  We describe a neural attention model with a learnable retinal sampling
lattice. The model is trained on a visual search task requiring the
classification of an object embedded in a visual scene amidst background
distractors using the smallest number of fixations. We explore the tiling
properties that emerge in the model's retinal sampling lattice after training.
Specifically, we show that this lattice resembles the eccentricity dependent
sampling lattice of the primate retina, with a high resolution region in the
fovea surrounded by a low resolution periphery. Furthermore, we find conditions
where these emergent properties are amplified or eliminated providing clues to
their function.


title:
Localization of a unicycle-like mobile robot using LRF and
  omni-directional camera

abstract:
  This paper addresses the localization problem. The extended Kalman filter
(EKF) is employed to localize a unicycle-like mobile robot equipped with a
laser range finder (LRF) sensor and an omni-directional camera. The LRF is used
to scan the environment which is described with line segments. The segments are
extracted by a modified least square quadratic method in which a dynamic
threshold is injected. The camera is employed to determine the robot's
orientation. The prediction step of the EKF is performed by extracting
parameters from the kinematic model and input signal of the robot. The
correction step is conducted with the implementation of a line matching
algorithm and the comparison between line's parameters of the local and global
maps. In the line matching algorithm, a conversion matrix is introduced to
reduce the computation cost. Experiments have been carried out in a real mobile
robot system and the results prove the applicability of the method for the
purpose of localization.


title:
Tangential Fluid flow within 3D narrow fissures: Conservative velocity
  fields on associated triangulations and transport processes

abstract:
  For a fissured medium with uncertainty in the knowledge of fractures'
geometry, a conservative tangential flow field is constructed, which is
consistent with the physics of stationary fluid flow in porous media and an
interpolated geometry of the cracks. The flow field permits computing
preferential fluid flow directions of the medium, rates of mechanical energy
dissipations and a stochastic matrix modeling stream lines and fluid mass
transportation, for the analysis of solute/contaminant mass advection-diffusion
as well as drainage times.


title: A novel platform for internet-based mobile robot systems

abstract:
  In this paper, we introduce a software and hardware structure for on-line
mobile robotic systems. The hardware mainly consists of a Multi-Sensor Smart
Robot connected to the Internet through 3G mobile network. The system employs a
client-server software architecture in which the exchanged data between the
client and the server is transmitted through different transport protocols.
Autonomous mechanisms such as obstacle avoidance and safe-point achievement are
implemented to ensure the robot safety. This architecture is put into operation
on the real Internet and the preliminary result is promising. By adopting this
structure, it will be very easy to construct an experimental platform for the
research on diverse tele-operation topics such as remote control algorithms,
interface designs, network protocols and applications etc.


title:
Input Switched Affine Networks: An RNN Architecture Designed for
  Interpretability

abstract:
  There exist many problem domains where the interpretability of neural network
models is essential for deployment. Here we introduce a recurrent architecture
composed of input-switched affine transformations - in other words an RNN
without any explicit nonlinearities, but with input-dependent recurrent
weights. This simple form allows the RNN to be analyzed via straightforward
linear methods: we can exactly characterize the linear contribution of each
input to the model predictions; we can use a change-of-basis to disentangle
input, output, and computational hidden unit subspaces; we can fully
reverse-engineer the architecture's solution to a simple task. Despite this
ease of interpretation, the input switched affine network achieves reasonable
performance on a text modeling tasks, and allows greater computational
efficiency than networks with standard nonlinearities.


title:
The analysis of topological structure in data using persistent homology:
  applications to lexical word association networks

abstract:
  Persistent homology is a technique recently developed in algebraic and
computational topology well-suited to analysing structure in complex,
high-dimensional data. In this paper, we exposit the theory of persistent
homology from first principles and detail a novel application of this method to
the field of computational linguistics. Using this method, we search for
clusters and other topological features among closely-associated words of the
English language. Furthermore, we compare the clustering abilities of
persistent homology and the commonly-used Markov clustering algorithm and
discuss improvements to basic persistent homology techniques to increase its
clustering efficacy.


title:
Proposal of algorithms for navigation and obstacles avoidance of
  autonomous mobile robot

abstract:
  This paper presents algorithms to navigate and avoid obstacles for an in-door
autonomous mobile robot. A laser range finder is used to obtain 3D images of
the environment. A new algorithm, namely 3D-to-2D image pressure and barriers
detection (IPaBD), is proposed to create a 2D global map from the 3D images.
This map is basic to design the trajectory. A tracking controller is developed
to control the robot to follow the trajectory. The obstacle avoidance is
addressed with the use of sonar sensors. An improved vector field histogram
(Improved-VFH) algorithm is presented with improvements to overcome some
limitations of the original VFH. Experiments have been conducted and the result
is encouraged.


title:
A duality-based optimization approach for model adaptivity in
  heterogeneous multiscale problems

abstract:
  This paper introduces a novel framework for model adaptivity in the context
of heterogeneous multiscale problems. The framework is based on the idea to
interpret model adaptivity as a minimization problem of local error indicators,
that are derived in the general context of the Dual Weighted Residual (DWR)
method. Based on the optimization approach a post-processing strategy is
formulated that lifts the requirement of strict a priori knowledge about
applicability and quality of effective models. This allows for the systematic,
"goal-oriented" tuning of effective models with respect to a quantity of
interest.
  The framework is tested numerically on elliptic diffusion problems with
different types of heterogeneous, random coefficients, as well as an
advection-diffusion problem with strong microscopic, random advection field.


title:
Discovery and Follow-up Observations of the Young Type Ia Supernova
  2016coj

abstract:
  The Type~Ia supernova (SN~Ia) 2016coj in NGC 4125 (redshift $z=0.004523$) was
discovered by the Lick Observatory Supernova Search 4.9 days after the fitted
first-light time (FFLT; 11.1 days before $B$-band maximum). Our first detection
(pre-discovery) is merely $0.6\pm0.5$ day after the FFLT, making SN 2016coj one
of the earliest known detections of a SN Ia. A spectrum was taken only 3.7 hr
after discovery (5.0 days after the FFLT) and classified as a normal SN Ia. We
performed high-quality photometry, low- and high-resolution spectroscopy, and
spectropolarimetry, finding that SN 2016coj is a spectroscopically normal SN
Ia, but with a high velocity of \ion{Si}{2} $\lambda$6355 ($\sim 12,600$\,\kms\
around peak brightness). The \ion{Si}{2} $\lambda$6355 velocity evolution can
be well fit by a broken-power-law function for up to a month after the FFLT. SN
2016coj has a normal peak luminosity ($M_B \approx -18.9 \pm 0.2$ mag), and it
reaches a $B$-band maximum \about16.0~d after the FFLT. We estimate there to be
low host-galaxy extinction based on the absence of Na~I~D absorption lines in
our low- and high-resolution spectra. The spectropolarimetric data exhibit weak
polarization in the continuum, but the \ion{Si}{2} line polarization is quite
strong ($\sim 0.9\% \pm 0.1\%$) at peak brightness.


title:
More on the admissible condition on differentiable maps $\varphi:
  (X^{\!A\!z},E;\nabla)\rightarrow Y$ in the construction of the non-Abelian
  Dirac-Born-Infeld action $S_{DBI}(\varphi,\nabla)$

abstract:
  In D(13.1) (arXiv:1606.08529 [hep-th]), we introduced an admissible condition
on differentiable maps $\varphi: (X^{\!A\!z}, E;\nabla)\rightarrow Y$ from an
Azumaya/matrix manifold $X^{\!A\!z}$ (with the fundamental module $E$) with a
connection $\nabla$ on $E$ to a manifold $Y$ in order to resolve a pull-push
issue in the construction of a non-Abelian-Dirac-Infeld action $S_{DBI}$ for
$(\varphi,\nabla)$ and to render $\nabla$ massless from the aspect of open
strings. The admissible condition ibidem consists of two parts: Condition (1)
and Condition (2). In this brief note, we examine these two conditions in more
detail and bring their geometric implications on $(\varphi,\nabla)$ and the
full action $S_{DBI}(\varphi,\nabla)+S_{CS/WZ}(\varphi,\nabla)$ more
transparent. In particular, we show that Condition (1) alone already implies
masslessness of $\nabla$ from open-string aspect; and that the additional
Condition (2) implies a decoupling of the nilpotent fuzzy cloud of
$\varphi(X^{\!A\!z})$ to the dynamics of $(\varphi, \nabla)$. We conclude with
a refined definition of admissible $(\varphi,\nabla)$ and a remark on the
anomaly factor in the integrand of the Chern-Simons/Wess-Zumino term
$S_{CS/WZ}(\varphi,\nabla)$ for D-branes based on the current study.


title:
Pulsar Timing Array Based Search for Supermassive Black Hole Binaries in
  the Square Kilometer Array Era

abstract:
  The advent of next generation radio telescope facilities, such as the Square
Kilometer Array (SKA), will usher in an era where a Pulsar Timing Array (PTA)
based search for gravitational waves (GWs) will be able to use hundreds of well
timed millisecond pulsars rather than the few dozens in existing PTAs. A
realistic assessment of the performance of such an extremely large PTA must
take into account the data analysis challenge posed by an exponential increase
in the parameter space volume due to the large number of so-called pulsar phase
parameters. We address this problem and present such an assessment for isolated
supermassive black hole binary (SMBHB) searches using a SKA era PTA containing
$10^3$ pulsars. We find that an all-sky search will be able to confidently
detect non-evolving sources with redshifted chirp mass of $10^{10}$ $M_\odot$
out to a redshift of about $28$ (corresponding to a rest-frame chirp mass of
$3.4\times 10^{8}$ $M_\odot$). We discuss the important implications that the
large distance reach of a SKA era PTA has on GW observations from optically
identified SMBHB candidates. If no SMBHB detections occur, a highly unlikely
scenario in the light of our results, the sky-averaged upper limit on strain
amplitude will be improved by about three orders of magnitude over existing
limits.


title: Sentiment Analysis for Twitter : Going Beyond Tweet Text

abstract:
  Analysing sentiment of tweets is important as it helps to determine the
users' opinion. Knowing people's opinion is crucial for several purposes
starting from gathering knowledge about customer base, e-governance,
campaigning and many more. In this report, we aim to develop a system to detect
the sentiment from tweets. We employ several linguistic features along with
some other external sources of information to detect the sentiment of a tweet.
We show that augmenting the 140 character-long tweet with information harvested
from external urls shared in the tweet as well as Social Media features
enhances the sentiment prediction accuracy significantly.


title: Threshold corrections in heterotic flux compactifications

abstract:
  We compute the one-loop threshold corrections to the gauge and gravitational
couplings for a large class of N=2 non-K\"ahler heterotic compactifications
with three-form flux, consisting in principal two-torus bundles over K3
surfaces. We obtain the results as sums of BPS-states contributions, depending
on the topological data of the bundle. We analyse also the worldsheet
non-perturbative corrections coming from instantons wrapping the torus fiber,
that are mapped under S-duality to D-instanton corrections in type I flux
compactifications.


title: Star bodies with completely symmetric sections

abstract:
  We say that a star body $K$ is completely symmetric if it has centroid at the
origin and its symmetry group $G$ forces any ellipsoid whose symmetry group
contains $G$, to be a ball. In this short note, we prove that if all central
sections of a star body $L$ are completely symmetric, then $L$ has to be a
ball. A special case of our result states that if all sections of $L$ are
origin symmetric and 1-symmetric, then $L$ has to be a Euclidean ball. This
answers a question from \cite{R2}. Our result is a consequence of a general
theorem that we establish, stating that if the restrictions in almost all
equators of a real function $f$ defined on the sphere, are isotropic functions,
then $f$ is constant a.e. In the last section of this note, applications,
improvements and related open problems are discussed and two additional open
questions from \cite{R} and \cite{R2} are answered.}


title: The empirical size of trained neural networks

abstract:
  ReLU neural networks define piecewise linear functions of their inputs.
However, initializing and training a neural network is very different from
fitting a linear spline. In this paper, we expand empirically upon previous
theoretical work to demonstrate features of trained neural networks. Standard
network initialization and training produce networks vastly simpler than a
naive parameter count would suggest and can impart odd features to the trained
network. However, we also show the forced simplicity is beneficial and, indeed,
critical for the wide success of these networks.


title: Infrared Problem in Quantum Acoustodynamics

abstract:
  Quantum electrodynamics (QED) provides a highly accurate description of
phenomena involving the interaction of atoms with light. We argue that the
quantum theory describing the interaction of cold atoms with a vibrating
membrane--quantum acoustodynamics (QAD)--shares many issues and features with
QED. Specifically, the adsorption of an atom on a vibrating membrane can be
viewed as the counterpart to QED radiative electron capture. A calculation of
the adsorption rate to lowest-order in the atom-phonon coupling is finite;
however, higher-order contributions suffer from an infrared problem mimicking
the case of radiative capture in QED. Terms in the perturbation series for the
adsorption rate diverge as a result of massless particles in the model
(flexural phonons of the membrane in QAD and photons in QED). We treat this
infrared problem in QAD explicitly to obtain finite results by regularizing
with a low-frequency cutoff that corresponds to the inverse size of the
membrane. Using a coherent state basis for the soft phonon final state, we then
sum the dominant contributions to derive a new formula for the multiphonon
adsorption rate of atoms on the membrane that gives results that are finite,
nonperturbative in the atom-phonon coupling, and consistent with the KLN
theorem. For micromembranes, we predict a reduction with increasing membrane
size for the low-energy adsorption rate. We discuss the relevance of this to
the adsorption of a cold gas of atomic hydrogen on suspended graphene.


title:
FPGA Based Implementation of Distributed Minority and Majority Voting
  Based Redundancy for Mission and Safety-Critical Applications

abstract:
  Electronic circuits and systems used in mission and safety-critical
applications usually employ redundancy in the design to overcome arbitrary
fault(s) or failure(s) and guarantee the correct operation. In this context,
the distributed minority and majority voting based redundancy (DMMR) scheme
forms an efficient alternative to the conventional N-modular redundancy (NMR)
scheme for implementing mission and safety-critical circuits and systems by
significantly minimizing their weight and design cost and also their design
metrics whilst providing a similar degree of fault tolerance. This article
presents the first FPGAs based implementation of example DMMR circuits and
compares it with counterpart NMR circuits on the basis of area occupancy and
critical path delay viz. area-delay product (ADP). The example DMMR circuits
and counterpart NMR circuits are able to accommodate the faulty or failure
states of 2, 3 and 4 function modules. For physical synthesis, two commercial
Xilinx FPGAs viz. Spartan 3E and Virtex 5 corresponding to 90nm and 65nm CMOS
processes, and two radiation-tolerant and military grade Xilinx FPGAs viz. QPro
Virtex 2 and QPro Virtex E corresponding to 150nm and 180nm CMOS processes were
considered for the NMR and DMMR circuit realizations which employ the 4-by-4
array multiplier as a representative function module. To achieve a fault
tolerance of 2 function modules, both the DMMR and the NMR schemes provide near
similar mean ADPs across all the four FPGAs. But while achieving a fault
tolerance of 3 function modules the DMMR features reduced ADP by 44.5% on
average compared to the NMR, and in achieving a fault tolerance of 4 function
modules the DMMR reports reduced ADP by 56.5% on average compared to the NMR
with respect to all the four FPGAs considered.


title: Where is the electric current driven in the Blandford-Znajek process?

abstract:
  The Blandford-Znajek process, the steady electromagnetic energy extraction
from a rotating black hole, is widely believed to work for driving relativistic
jets, although it is still under debate where the electric current is driven.
We address this issue analytically by investigating the time-dependent state in
the Boyer-Lindquist and Kerr-Schild coordinate systems. This analysis suggests
that a non-ideal magnetohydrodynamic region is required in the time-dependent
state, while not in the steady state.


title: The Upper Bound on Knots in Neural Networks

abstract:
  Neural networks with rectified linear unit activations are essentially
multivariate linear splines. As such, one of many ways to measure the
"complexity" or "expressivity" of a neural network is to count the number of
knots in the spline model. We study the number of knots in fully-connected
feedforward neural networks with rectified linear unit activation functions. We
intentionally keep the neural networks very simple, so as to make theoretical
analyses more approachable. An induction on the number of layers $l$ reveals a
tight upper bound on the number of knots in $\mathbb{R} \to \mathbb{R}^p$ deep
neural networks. With $n_i \gg 1$ neurons in layer $i = 1, \dots, l$, the upper
bound is approximately $n_1 \dots n_l$. We then show that the exact upper bound
is tight, and we demonstrate the upper bound with an example. The purpose of
these analyses is to pave a path for understanding the behavior of general
$\mathbb{R}^q \to \mathbb{R}^p$ neural networks.


title:
Triple junction drag effects during topological changes in the evolution
  of polycrystalline microstructures

abstract:
  Experiments, theory and atomistic simulations show that finite triple
junction mobility results in non-equilibrium triple junction angles in evolving
polycrystalline systems. These angles have been predicted and verified for
cases where grain boundary migration is steady-state. Yet, steady-state never
occurs during the evolution of polycrystalline microstructures as a result of
changing grain size and topological events (e.g., grain face/edge switching -
"$T_1$" process, or grain disappearance "$T_2$" or "$T_3$" processes). We
examine the non-steady evolution of the triple junction angle in the vicinity
of topological events and show that large deviations from equilibrium and/or
steady-state angles occur. We analyze the characteristic relaxation time of
triple junction angles $\tau$ by consideration of a pair of topological events,
beginning from steady-state migration. Using numerical results and theoretical
analysis we predict how the triple junction angle varies with time and how
$\tau$ varies with triple junction mobility. We argue that it is precisely
those cases where grain boundaries are moving quickly (e.g., topological
process in nanocrystalline materials), that the classical steady-state
prediction of the finite triple junction mobility triple junction angle is
inapplicable and may only be applied qualitatively.


title:
X-Shooter spectroscopy of young stellar objects - VI - HI line
  decrements

abstract:
  Hydrogen recombination emission lines commonly observed in accreting young
stellar objects represent a powerful tracer for the gas conditions in the
circumstellar structures. Here we perform a study of the HI decrements and line
profiles, from the Balmer and Paschen lines detected in the X-Shooter spectra
of a homogeneous sample of 36 T Tauri stars in Lupus, the accretion and stellar
properties of which were already derived in a previous work. We aim to obtain
information on the gas physical conditions to derive a consistent picture of
the HI emission mechanisms in pre-main sequence low-mass stars. We have
empirically classified the sources based on their HI line profiles and
decrements. We identified four Balmer decrement types (classified as 1, 2, 3,
and 4) and three Paschen decrement types (A, B, and C), characterised by
different shapes. We first discussed the connection between the decrement types
and the source properties and then compared the observed decrements with
predictions from recently published local line excitation models. One third of
the objects show lines with narrow symmetric profiles, and present similar
Balmer and Paschen decrements (straight decrements, types 2 and A). Lines in
these sources are consistent with optically thin emission from gas with
hydrogen densities of order 10^9 cm^-3 and 5000<T<15000 K. These objects are
associated with low mass accretion rates. Type 4 (L-shaped) Balmer and type B
Paschen decrements are found in conjunction with very wide line profiles and
are characteristic of strong accretors, with optically thick emission from
high-density gas (log n_H > 11 cm^-3). Type 1 (curved) Balmer decrements are
observed only in three sub-luminous sources viewed edge-on, so we speculate
that these are actually reddened type 2 decrements. About 20% of the objects
present type 3 Balmer decrements (bumpy), which cannot be reproduced with
current models.


title: Entangled states of two quantum dots mediated by Majorana fermions

abstract:
  With the assistance of a pair of Majorana fermions, we propose schemes to
entangle two quantum dots by Lyapunov control in the charge and spin degrees of
freedom. Four different schemes are considered, i.e., the teleportation scheme,
the crossed Andreev reflection scheme, the intradot spin flip scheme, and the
scheme beyond the intradot spin flip. We demonstrate that the entanglement can
be generated by modulating the chemical potential of quantum dots with square
pulses, which is easily realized in practice. In contrast to Lyapunov control,
the preparation of entangled states by adiabatic passage is also discussed.
There are two advantages in the scheme by Lyapunov control, i.e., it is
flexible to choose a control Hamiltonian, and the control time is much shorter
with respect to the scheme by adiabatic passage. Furthermore, we find that the
results are quite different by different adiabatic passages in the scheme
beyond the intradot spin flip, which can be understood as an effect of quantum
destructive interference.


title:
An Efficient Partial Sums Generator for Constituent Code based
  Successive Cancellation Decoding of Polar Codes

abstract:
  This paper proposes the architecture of partial sum generator for constituent
codes based polar code decoder. Constituent codes based polar code decoder has
the advantage of low latency. However, no purposefully designed partial sum
generator design exists that can yield desired timing for the decoder. We first
derive the mathematical presentation with the partial sums set $\bm{\beta^c}$
which is corresponding to each constituent codes. From this, we concoct a
shift-register based partial sum generator. Next, the overall architecture and
design details are described, and the overhead compared with conventional
partial sum generator is evaluated. Finally, the implementation results with
both ASIC and FPGA technology and relevant discussions are presented.


title:
Time-dependent current into and through multilevel parallel quantum dots
  in a photon cavity

abstract:
  We analyze theoretically the charging current into, and the transport current
through, a nanoscale two-dimensional electron system with two parallel quantum
dots embedded in a short wire placed in a photon cavity. A plunger gate is used
to place specific many-body states of the interacting system in the bias window
defined by the external leads. We show how the transport phenomena active in
the many-level complex central system strongly depend on the gate voltage. We
identify a resonant transport through the central system as the two spin
components of the one-electron ground state are in the bias window. This
resonant transport through the lowest energy electron states seems to a large
extent independent of the detuned photon field when judged from the transport
current. This could be expected in the small bias regime, but an observation of
the occupancy of the states of the system reveals that this picture is not
entirely true. The current does not reflect slower photon-active internal
transitions bringing the system into the steady state. The number of initially
present photons determines when the system reaches the real steady state. With
two-electron states in the bias window we observe a more complex situation with
intermediate radiative and nonradiative relaxation channels leading to a steady
state with a weak nonresonant current caused by inelastic tunneling through the
two-electron ground state of the system. The presence of the radiative channels
makes this phenomena dependent on the number of photons initially in the
cavity.


title:
Sigature of the universal super Efimov Effect: three-body contact in two
  dimensional Fermi gases

abstract:
  A new class of universal "three-body" bound states has been recently
predicted theoretically for identical fermions interacting at p-wave resonance
in two dimensions. This phenomenon is called the super Efimov effect since the
binding energies of the states follow a intriguing double exponential scaling.
However, experimental resolution of this scaling is expected to meet formidable
challenges. In this work, we introduce a new thermodynamic quantity, the
three-body contact $C_\theta$, to quantify three-body correlations in a two
dimensional gas composed of the resonantly interacting fermions; the contact
$C_\theta$ is the consequence of the underlying universal super Efimov effect
in the many-body context. We show how $C_\theta$ affects physical observables
such as the radio-frequency spectrum, the momentum distribution and the atom
loss rate. Signature of the elusive super Efimov effect in the thermodynamic
system can be pinned down by the detection of the three-body contact $C_\theta$
via these observables.


title: Search for $D^{0}$ decays to invisible final states at Belle

abstract:
  We report the result from the first search for $D^0$ decays to invisible
final states. The analysis is performed on a data sample of 924 $\rm{fb}^{-1}$
collected at and near the $\Upsilon(4S)$ and $\Upsilon(5S)$ resonances with the
Belle detector at the KEKB asymmetric-energy $e^{+}e^{-}$ collider. The
absolute branching fraction is determined using an inclusive $D^0$ sample,
obtained by fully reconstructing the rest of the particle system including the
other charmed particle. No significant signal yield is observed and an upper
limit of $9.4\times 10^{-5}$ is set on the branching fraction of $D^0$ to
invisible final states at 90\% confidence level.


title:
Effective restoration of dipole sum rules within the renormalized
  random-phase approximation

abstract:
  The dipole excitations for calcium and zirconium isotopes are studied within
the fully self-consistent Hartree-Fock mean field incorporated with the
renormalized random-phase approximation (RRPA) using the Skyrme interaction
SLy5. The RRPA takes into account the effect of ground-state correlations
beyond RPA owing to the Pauli principle between the particle-hole pairs that
form the RPA excitations as well as the correlations due to the
particle-particle and hole-hole transitions, whose effects are treated here in
an effective way. By comparing the RPA results with the RRPA ones, which are
obtained for isoscalar (IS) and isovector (IV) dipole excitations in $^{48, 52,
58}$Ca and $^{90, 96, 110}$Zr, it is shown that ground-state correlations
beyond the RPA reduce the IS transition strengths. They also shift up the
energy of the lowest IV dipole state and slightly push down the peak energy of
the IV giant dipole resonance. As the result, the energy-weighted sums of
strengths of both IS and IV modes decrease, causing the violation of the
corresponding energy-weight sum rules (EWSR). It is shown that this sum rule
violation can be eliminated by taking into account the contribution of the
particle-particle and hole-hole excitations together with the particle-hole
ones in a simple and perturbative way. Consequently, the ratio of the
energy-weighted sum of strengths of the pygmy dipole resonance to that of the
giant dipole resonance increases.


title:
kirchhoff index and degree kirchhoff index of complete multipartite
  graph

abstract:
  The Kirchhoff index of a graph is defined as half of the sum of all effective
resistance distances between any two vertices. Assuming a complete multipartite
graph G, by methods from linear algebra we explicitly formulate effective
resistance distances between any two vertices of G, and its Kirchhoff index. In
rest of paper we explore extremal value of Kirchhoff index for multipartite
graphs


title:
Diagonal magnetoelectric susceptibility and effect of Fe-doping in a
  polar ferrimagnet Mn2Mo3O8

abstract:
  We investigate a large variation in a diagonal component of the linear
magnetoelectric (ME) susceptibility in a polar ferrimagnet Mn2Mo3O8 while
changing the magnetic-ion site from orbital-quenched Mn2+ to Fe2+ with strong
uniaxial anisotropy. In Mn2Mo3O8, the linear ME susceptibility is dominated by
the non-relativistic exchange striction mechanism, showing a positive value at
low temperature and a critical behavior toward negative divergence around the
transition temperature. This negative peak value becomes four times larger when
50% of Mn2+ ions are replaced with Fe2+ ion, highlighting the beneficial
perspective of the compositionally-tunable ME effect. As the doped Fe increases
in fraction, gradual negative shift of the ME coefficient is observed around
the lowest temperature, which manifests relativistic single-site origin of the
ME susceptibility. Further doping with x >= 75% in (Mn1-xFex)2Mo3O8, the ME
coefficient becomes negative in the entire temperature region. Such a
composition dependence can be explained in terms of the chemical preference for
the two types of magnetic sites of Mn/Fe ions. The present study demonstrates
the large tunability of ME effect by substituting the magnetic ion with the
primary structural/magnetic characters kept intact.


title: How to Find Gravitationally Lensed Type Ia Supernovae

abstract:
  Type Ia supernovae (SNe Ia) that are multiply imaged by gravitational lensing
can extend the SN Ia Hubble diagram to very high redshifts $(z\gtrsim 2)$,
probe potential SN Ia evolution, and deliver high-precision constraints on
$H_0$, $w$, and $\Omega_m$ via time delays. However, only one, iPTF16geu, has
been found to date, and many more are needed to achieve these goals. To
increase the multiply imaged SN Ia discovery rate, we present a simple
algorithm for identifying gravitationally lensed SN Ia candidates in cadenced,
wide-field optical imaging surveys. The technique is to look for supernovae
that appear to be hosted by elliptical galaxies, but that have absolute
magnitudes implied by the apparent hosts' photometric redshifts that are far
brighter than the absolute magnitudes of normal SNe Ia (the brightest type of
supernovae found in elliptical galaxies). Importantly, this purely photometric
method does not require the ability to resolve the lensed images for discovery.
AGN, the primary sources of contamination that affect the method, can be
controlled using catalog cross-matches and color cuts. Highly magnified
core-collapse supernovae will also be discovered as a byproduct of the method.
Using a Monte Carlo simulation, we forecast that LSST can discover up to 500
multiply imaged SNe Ia using this technique in a 10-year $z$-band search, more
than an order of magnitude improvement over previous estimates (Oguri &
Marshall 2010). We also predict that ZTF should find up to 10 multiply imaged
SNe Ia using this technique in a 3-year $R$-band search---despite the fact that
this survey will not resolve a single system.


title: Wakefields of a Beam near a Single Plate in a Flat Dechirper

abstract:
  We give formulas for the longitudinal, transverse, and quad point charge
wakes for a short bunch of electrons passing by one plate of a flat dechirper.


title: Cost-Sensitive Reference Pair Encoding for Multi-Label Learning

abstract:
  Label space expansion for multi-label classification (MLC) is a methodology
that encodes the original label vectors to higher dimensional codes before
training and decodes the predicted codes back to the label vectors during
testing. The methodology has been demonstrated to improve the performance of
MLC algorithms when coupled with off-the-shelf error-correcting codes for
encoding and decoding. Nevertheless, such a coding scheme can be complicated to
implement, and cannot easily satisfy a common application need of
cost-sensitive MLC---adapting to different evaluation criteria of interest. In
this work, we show that a simpler coding scheme based on the concept of a
reference pair of label vectors achieves cost-sensitivity more naturally. In
particular, our proposed cost-sensitive reference pair encoding (CSRPE)
algorithm contains cluster-based encoding, weight-based training and
voting-based decoding steps, all utilizing the cost information. Furthermore,
we leverage the cost information embedded in the code space of CSRPE to propose
a novel active learning algorithm for cost-sensitive MLC. Extensive
experimental results verify that CSRPE performs better than state-of-the-art
algorithms across different MLC criteria. The results also demonstrate that the
CSRPE-backed active learning algorithm is superior to existing algorithms for
active MLC, and further justify the usefulness of CSRPE.


title: Electronic Structure and Stability of the CH3NH3PbBr3 (001) Surface

abstract:
  The energetics and the electronic structure of methylammonium lead bromine
(CH3NH3PbBr3) perovskite (001) surfaces are studied based on density functional
theory. By examining the surface grand potential, we predict that the
CH3NH3Br-terminated (001) surface is energetically more favorable than the
PbBr2-terminated (001) surface, under thermodynamic equilibrium conditions of
bulk CH3NH3PbBr3. The electronic structure of each of these two different
surface terminations retains some of the characteristics of the bulk, while new
surface states are found near band edges which may affect the photovoltaic
performance in the solar cells based on CH3NH3PbBr3. The calculated electron
affinity of CH3NH3PbBr3 reveals a sizable difference for the two surface
terminations, indicating a possibility of tuning the band offset between the
halide perovskite and adjacent electrode with proper interface engineering.


title: Laughlin's argument for the quantized thermal Hall effect

abstract:
  We extend Laughlin's magnetic-flux-threading argument to the quantized
thermal Hall effect. A proper analogue of Laughlin's adiabatic magnetic-flux
threading process for the case of the thermal Hall effect is given in terms of
an external gravitational field. From the perspective of the edge theories of
quantum Hall systems, the quantized thermal Hall effect is closely tied to the
breakdown of large diffeomorphism invariance, that is, a global gravitational
anomaly. In addition, we also give an argument from the bulk perspective in
which a free energy, decomposed into its Fourier modes, is adiabatically
transferred under an adiabatic process involving external gravitational
perturbations.


title: Social Behavior Prediction from First Person Videos

abstract:
  This paper presents a method to predict the future movements (location and
gaze direction) of basketball players as a whole from their first person
videos. The predicted behaviors reflect an individual physical space that
affords to take the next actions while conforming to social behaviors by
engaging to joint attention. Our key innovation is to use the 3D reconstruction
of multiple first person cameras to automatically annotate each other's the
visual semantics of social configurations.
  We leverage two learning signals uniquely embedded in first person videos.
Individually, a first person video records the visual semantics of a spatial
and social layout around a person that allows associating with past similar
situations. Collectively, first person videos follow joint attention that can
link the individuals to a group. We learn the egocentric visual semantics of
group movements using a Siamese neural network to retrieve future trajectories.
We consolidate the retrieved trajectories from all players by maximizing a
measure of social compatibility---the gaze alignment towards joint attention
predicted by their social formation, where the dynamics of joint attention is
learned by a long-term recurrent convolutional network. This allows us to
characterize which social configuration is more plausible and predict future
group trajectories.


title: Experimental summary for heavy flavor production

abstract:
  Measurements of heavy flavor production in heavy-ion collisions have played
an important role in understanding the properties of the quark-gluon plasma
created in such collision. Due to their large masses, heavy flavor quarks
present unique sensitivity to the kinematics as well as the dynamics of the hot
and dense medium. In this article, a selection of recent measurements on heavy
flavor production in p+p, p+A and A+A collisions at both RHIC and LHC energies
will be presented. The measurements in p+p collisions serve as benchmarks to
fundamental theories, and as references to similar studies in A+A collisions
where the hot medium effects are present. On the other hand, the measurements
in p+A collisions can help to quantify the cold nuclear matter effects which
are also in effect in A+A collisions and thus need to be taken into account
when interpreting the measurements in heavy-ion collisions. The experimental
results from A+A collisions are discussed and compared to theoretical
calculations, which can shed lights on the understanding of the quark-gluon
plasma.


title: On Koml\'os' tiling theorem in random graphs

abstract:
  Conlon, Gowers, Samotij, and Schacht showed that for a given graph $H$ and a
constant $\gamma > 0$, there exists $C > 0$ such that if $p \ge Cn^{-1/m_2(H)}$
then asymptotically almost surely every spanning subgraph $G$ of the random
graph $\mathcal{G}(n,p)$ with minimum degree at least $\delta(G) \ge (1 -
1/\chi_{\mathrm{cr}}(H) + \gamma )np$ contains an $H$-packing that covers all
but at most $\gamma n$ vertices. Here, $\chi_{\mathrm{cr}}(H)$ denotes the
critical chromatic threshold, a parameter introduced by Koml\'os. We show that
this theorem can be bootstraped to obtain an $H$-packing covering all but at
most $\gamma (C/p)^{m_2(H)}$ vertices, which is strictly smaller when $p > C
n^{-1/m_2(H)}$. In the case where $H = K_3$ this answers the question of
Balogh, Lee, and Samotij. Furthermore, we give an upper bound on the size of an
$H$-packing for certain ranges of $p$.


title: Gradient optimization of finite projected entangled pair states

abstract:
  The projected entangled pair states (PEPS) methods have been proved to be
powerful tools to solve the strongly correlated quantum many-body problems in
two-dimension. However, due to the high computational scaling with the virtual
bond dimension $D$, in a practical application PEPS are often limited to rather
small bond dimensions, which may not be large enough for some highly entangled
systems, for instance, the frustrated systems. The optimization of the ground
state using time evolution method with simple update scheme may go to a larger
bond dimension. However, the accuracy of the rough approximation to the
environment of the local tensors is questionable. Here, we demonstrate that
combining the time evolution method with simple update, Monte Carlo sampling
techniques and gradient optimization will offer an efficient method to
calculate the PEPS ground state. By taking the advantages of massive parallel
computing, we can study the quantum systems with larger bond dimensions up to
$D$=10 without resorting to any symmetry. Benchmark tests of the method on the
$J_1$-$J_2$ model give impressive accuracy compared with exact results.


title:
Understanding the negative temperature coefficient phenomenon in
  methane-air mixtures at high pressures

abstract:
  Design and operation of advanced reactors such as fuel reformers require
reliable micro-kinetic models that capture the dynamics of the reaction. The
negative temperature coefficient phenomenon causes a reduction in mixture
temperature for increasing inlet temperatures. However, micro-kinetic models
available in the literature have not been critically evaluated for their
ability to capture this phenomenon. Consequently, the ability to predict system
behavior for particular application situations, such as in the presence of
certain diluents or at high pressures, is largely missing. In this work, we
adapt multiple reaction mechanisms from literature and compare them for methane
oxidation over a wide range of pressures and temperatures. Using reaction path
analysis and sensitivity analysis, we find that the C2 formation through the
recombination pathway is chiefly responsible for negative temperature
coefficient behavior. With this insight, the dependence of steam addition and
pressure on is also discussed.


title: Plurigraph coloring and scheduling problems

abstract:
  We define a new type of vertex coloring which generalizes vertex coloring in
graphs, hypergraphs, and simplicial complexes. This coloring also generalizes
oriented coloring, acyclic coloring, and star coloring. There is an associated
symmetric function in noncommuting variables for which we give a
deletion-contraction formula. In the case of graphs this symmetric function in
noncommuting variables agrees with the chromatic symmetric function in
noncommuting variables of Gebhard and Sagan. Our vertex coloring is a special
case of the scheduling problems defined by Breuer and Klivans. We show how the
deletion-contraction law can be applied to scheduling problems. Also, we show
that the chromatic symmetric function determines the degree sequence of uniform
hypertrees, but there exist pairs on $3$-uniform hypertrees which are not
isomorphic yet have the same chromatic symmetric function.


title: Teaching Functional Patterns through Robotic Applications

abstract:
  We present our approach to teaching functional programming to First Year
Computer Science students at Middlesex University through projects in robotics.
A holistic approach is taken to the curriculum, emphasising the connections
between different subject areas. A key part of the students' learning is
through practical projects that draw upon and integrate the taught material. To
support these, we developed the Middlesex Robotic plaTfOrm (MIRTO), an
open-source platform built using Raspberry Pi, Arduino, HUB-ee wheels and
running Racket (a LISP dialect). In this paper we present the motivations for
our choices and explain how a number of concepts of functional programming may
be employed when programming robotic applications. We present some students'
work with robotics projects: we consider the use of robotics projects to have
been a success, both for their value in reinforcing students' understanding of
programming concepts and for their value in motivating the students.


title: Learn Quantum Mechanics with Haskell

abstract:
  To learn quantum mechanics, one must become adept in the use of various
mathematical structures that make up the theory; one must also become familiar
with some basic laboratory experiments that the theory is designed to explain.
The laboratory ideas are naturally expressed in one language, and the
theoretical ideas in another. We present a method for learning quantum
mechanics that begins with a laboratory language for the description and
simulation of simple but essential laboratory experiments, so that students can
gain some intuition about the phenomena that a theory of quantum mechanics
needs to explain. Then, in parallel with the introduction of the mathematical
framework on which quantum mechanics is based, we introduce a calculational
language for describing important mathematical objects and operations, allowing
students to do calculations in quantum mechanics, including calculations that
cannot be done by hand. Finally, we ask students to use the calculational
language to implement a simplified version of the laboratory language, bringing
together the theoretical and laboratory ideas.


title: The Bricklayer Ecosystem - Art, Math, and Code

abstract:
  This paper describes the Bricklayer Ecosystem - a freely-available online
educational ecosystem created for people of all ages and coding backgrounds.
Bricklayer is designed in accordance with a "low-threshold infinite ceiling"
philosophy and has been successfully used to teach coding to primary school
students, middle school students, university freshmen, and in-service secondary
math teachers. Bricklayer programs are written in the functional programming
language SML and, when executed, create 2D and 3D artifacts. These artifacts
can be viewed using a variety of third-party tools such as LEGO Digital
Designer (LDD), LDraw, Minecraft clients, Brickr, as well as STereoLithography
viewers.


title: Proust: A Nano Proof Assistant

abstract:
  Proust is a small Racket program offering rudimentary interactive assistance
in the development of verified proofs for propositional and predicate logic. It
is constructed in stages, some of which are done by students before using it to
complete proof exercises, and in parallel with the study of its theoretical
underpinnings, including elements of Martin-Lof type theory. The goal is
twofold: to demystify some of the machinery behind full-featured proof
assistants such as Coq and Agda, and to better integrate the study of formal
logic with other core elements of an undergraduate computer science curriculum.


title:
Maximizing Non-Monotone DR-Submodular Functions with Cardinality
  Constraints

abstract:
  We consider the problem of maximizing a non-monotone DR-submodular function
subject to a cardinality constraint. Diminishing returns (DR) submodularity is
a generalization of the diminishing returns property for functions defined over
the integer lattice. This generalization can be used to solve many machine
learning or combinatorial optimization problems such as optimal budget
allocation, revenue maximization, etc. In this work we propose the first
polynomial-time approximation algorithms for non-monotone constrained
maximization. We implement our algorithms for a revenue maximization problem
with a real-world dataset to check their efficiency and performance.


title:
Domain-Specific Languages of Mathematics: Presenting Mathematical
  Analysis Using Functional Programming

abstract:
  We present the approach underlying a course on "Domain-Specific Languages of
Mathematics", currently being developed at Chalmers in response to difficulties
faced by third-year students in learning and applying classical mathematics
(mainly real and complex analysis). The main idea is to encourage the students
to approach mathematical domains from a functional programming perspective: to
identify the main functions and types involved and, when necessary, to
introduce new abstractions; to give calculational proofs; to pay attention to
the syntax of the mathematical expressions; and, finally, to organise the
resulting functions and types in domain-specific languages.


title:
Gaussian beta ensembles at high temperature: eigenvalue fluctuations and
  bulk statistics

abstract:
  We study the limiting behavior of Gaussian beta ensembles in the regime where
$\beta n = const$ as $n \to \infty$. The results are (1) Gaussian fluctuations
for linear statistics of the eigenvalues, and (2) Poisson convergence of the
bulk statistics. (2) is an alternative proof of the result by
F.~Benaych-Georges and S.~P\'ech\'e (2015) with the explicit form of the
intensity measure.


title: vtreat: a data.frame Processor for Predictive Modeling

abstract:
  We look at common problems found in data that is used for predictive modeling
tasks, and describe how to address them with the vtreat R package. vtreat
prepares real-world data for predictive modeling in a reproducible and
statistically sound manner. We describe the theory of preparing variables so
that data has fewer exceptional cases, making it easier to safely use models in
production. Common problems dealt with include: infinite values, invalid
values, NA, too many categorical levels, rare categorical levels, and new
categorical levels (levels seen during application, but not during training).
Of special interest are techniques needed to avoid needlessly introducing
undesirable nested modeling bias (which is a risk when using a
data-preprocessor).


title:
Characterizations of asymptotic distributions of continuous-time
  P\'{o}lya processes

abstract:
  We propose an elementary but effective approach to studying a general class
of Poissonized tenable and balanced urns on two colors. We characterize the
asymptotic behavior of the process via a partial differential equation that
governs the process, coupled with the method of moments applied in a
bootstrapped manner. We show that the limiting distribution of the process
underlying the Bagchi-Pal urn is gamma. We also look into the tenable and
balanced processes associated with randomized replacement matrix. Similar
results carry over to the process, with minor modifications in the methods of
proof, done mutatis mutandis.


title: Upper bounds for $s$-distance sets and equiangular lines

abstract:
  The set of points in a metric space is called an $s$-distance set if pairwise
distances between these points admit only $s$ distinct values. Two-distance
spherical sets with the set of scalar products $\{\alpha, -\alpha\}$,
$\alpha\in[0,1)$, are called equiangular. The problem of determining the
maximum size of $s$-distance sets in various spaces has a long history in
mathematics. We suggest a new method of bounding the size of an $s$-distance
set in compact two-point homogeneous spaces via zonal spherical functions. This
method allows us to prove that the maximum size of a spherical two-distance set
in $\mathbb{R}^n$, $n\geq 7$, is $\frac{n(n+1)}2$ with possible exceptions for
some $n=(2k+1)^2-3$, $k \in \mathbb{N}$. We also prove the universal upper
bound $\sim \frac 2 3 n a^2$ for equiangular sets with $\alpha=\frac 1 a$ and,
employing this bound, prove a new upper bound on the size of equiangular sets
in all dimensions. Finally, we classify all equiangular sets reaching this new
bound.


title: Wearable Assistive Devices for the Blind

abstract:
  Assistive devices are a key aspect in wearable systems for biomedical
applications, as they represent potential aids for people with physical and
sensory disabilities that might lead to improvements in the quality of life.
This chapter focuses on wearable assistive devices for the blind. It intends to
review the most significant work done in this area, to present the latest
approaches for assisting this population and to understand universal design
concepts for the development of wearable assistive devices and systems for the
blind.


title:
Calculation of Evaluation Variables for High Gradient Magnetic
  Separation with an Idealized Capture Model

abstract:
  This paper regards feed mine as a mixture of intergrowths and pure
non-magnetic mineral particles, presents a method to calculate the evaluation
variables such as grade and recovery in high gradient magnetic separation
(HGMS). A idealized capture model is constructed in which the interaction
between particles is not taken into account and only for the initial
aggregation condition that the separator has the highest capture efficiency. In
the model we adopt the functions that use nominal particle radius and magnetic
mineral content as independent variables to describe volume fraction
distribution and capture efficiency of intergrowths respectively. Through
adding multi-wire magnetic fields and setting periodic boundary conditions in
flow field analysis, we modify the computational domain of the single-wire
capture theory to a element domain that periodically appears in the multi-wire
matrix. By means of finite element software, particle trajectories, flow field
and magnetic field are clearly exhibited, and then capture efficiency function
is obtained by interpolation method. The calculated evaluation variables
theoretically represent the best performance of magnetic separator for a given
feed. They can assist mineral engineers to evaluate or compare the effects of
different magnetic separation systems in advance. We use removal of iron
impurity from kaolin as an example to illustrate the presented calculation
method. The results quantitatively compare the evaluation variables of the
separation at different magnetic fields and show that the advantage of higher
magnetic field in separation efficiency decreases with the increase of
saturation magnetization of magnetic mineral.


title: Fast Wavenet Generation Algorithm

abstract:
  This paper presents an efficient implementation of the Wavenet generation
process called Fast Wavenet. Compared to a naive implementation that has
complexity O(2^L) (L denotes the number of layers in the network), our proposed
approach removes redundant convolution operations by caching previous
calculations, thereby reducing the complexity to O(L) time. Timing experiments
show significant advantages of our fast implementation over a naive one. While
this method is presented for Wavenet, the same scheme can be applied anytime
one wants to perform autoregressive generation or online prediction using a
model with dilated convolution layers. The code for our method is publicly
available.


title: Graph's Topology and Free Energy of a Spin Model on the Graph

abstract:
  In this work we show that there is a direct relationship between a graph's
topology and the free energy of a spin system on the graph. We develop a method
of separating topological and enthalpic contributions to the free energy, and
find that considering the topology is sufficient to qualitatively compare the
free energies of different graph systems at high temperature, even when the
energetics are not fully known. This method was applied to the metal lattice
system with defects, and we found that it partially explains why point defects
are more stable than high-dimensional defects. Given the energetics, we can
even quantitatively compare free energies of different graph structures via a
closed form of linear graph contributions. The closed form is applied to
predict the sequence space free energy of lattice proteins, which is a key
factor determining the designability of a protein structure.


title: The shapes of nuclei

abstract:
  Gerry Brown initiated some early studies on the coexistence of different
nuclear shapes. The subject has continued to be of interest and is crucial for
understanding nuclear fission. We now have a very good picture of the potential
energy surface with respect to shape degrees of freedom in heavy nuclei, but
the dynamics remain problematic. In contrast, the early studies on light nuclei
were quite successful in describing the mixing between shapes. Perhaps a new
approach in the spirit of the old calculations could better elucidate the
character of the fission dynamics and explain phenomena that current theory
does not model well.


title: Dispersing Points on Intervals

abstract:
  We consider a problem of dispersing points on disjoint intervals on a line.
Given n pairwise disjoint intervals sorted on a line, we want to find a point
in each interval such that the minimum pairwise distance of these points is
maximized. Based on a greedy strategy, we present a linear time algorithm for
the problem. Further, we also solve in linear time the cycle version of the
problem where the intervals are given on a cycle.


title: Between the stochastic six vertex model and Hall-Littlewood processes

abstract:
  We prove that the joint distribution of the values of the height function for
the stochastic six vertex model in a quadrant along a down-right path coincides
with that for the lengths of the first columns of partitions distributed
according to certain Hall-Littlewood processes. In the limit when one of the
quadrant axes becomes continuous, we also show that the two-dimensional random
field of the height function values has the same distribution as the lengths of
the first columns of partitions from certain ascending Hall-Littlewood
processes evolving under a Robinson-Schensted-Knuth type Markovian evolution.

categories: math.PR cond-mat.stat-mech math-ph math.CO math.MP


title: A proof of Pyber's base size conjecture

abstract:
  Building on earlier papers of several authors, we establish that there exists
a universal constant $c > 0$ such that the minimal base size $b(G)$ of a
primitive permutation group $G$ of degree $n$ satisfies $\log |G| / \log n \leq
b(G) < 45 (\log |G| / \log n) + c$. This finishes the proof of Pyber's base
size conjecture. An ingredient of the proof is that for the distinguishing
number $d(G)$ (in the sense of Albertson and Collins) of a transitive
permutation group $G$ of degree $n > 1$ we have the estimates $\sqrt[n]{|G|} <
d(G) \leq 48 \sqrt[n]{|G|}$.


title:
Local Gaussian Process Model for Large-scale Dynamic Computer
  Experiments

abstract:
  The recent accelerated growth in the computing power has generated
popularization of experimentation with dynamic computer models in various
physical and engineering applications. Despite the extensive statistical
research in computer experiments, most of the focus had been on the theoretical
and algorithmic innovations for the design and analysis of computer models with
scalar responses.
  In this paper, we propose a computationally efficient statistical emulator
for a large-scale dynamic computer simulator (i.e., simulator which gives time
series outputs). The main idea is to first find a good local neighbourhood for
every input location, and then emulate the simulator output via a singular
value decomposition (SVD) based Gaussian process (GP) model. We develop a new
design criterion for sequentially finding this local neighbourhood set of
training points. Several test functions and a real-life application have been
used to demonstrate the performance of the proposed approach over a naive
method of choosing local neighbourhood set using the Euclidean distance among
design points.


title: Phenomenology of buoyancy-driven turbulence: recent results

abstract:
  In this paper, we review the recent developments in the field of
buoyancy-driven turbulence. Scaling and numerical arguments show that the
stably-stratified turbulence with moderate stratification has kinetic energy
spectrum $E_u(k) \sim k^{-11/5}$ and the kinetic energy flux $\Pi_u(k) \sim
k^{-4/5}$, which is called Bolgiano-Obukhov scaling. The energy flux for the
Rayleigh-B\'{e}nard convection (RBC) however is approximately constant in the
inertial range that results in Kolmorogorv's spectrum ($E_u(k) \sim k^{-5/3}$)
for the kinetic energy. The phenomenology of RBC should apply to other flows
where the buoyancy feeds the kinetic energy, e.g. bubbly turbulence and
fully-developed Rayleigh Taylor instability. This paper also covers several
models that predict the Reynolds and Nusselt numbers of RBC. Recent works show
that the viscous dissipation rate of RBC scales as $\sim \mathrm{Ra}^{1.3}$,
where $\mathrm{Ra}$ is the Rayleigh number.


title:
Generalized Shared Control versus Classical Shared Control: Illustrative
  Examples

abstract:
  Shared control fuses operator inputs and autonomy inputs into a single
command. However, if environmental or operator predictions are multimodal,
state of the art approaches are suboptimal with respect to safety, efficiency,
and operator-autonomy agreement: even under mildly challenging conditions,
existing approaches can fuse two safe inputs into an unsafe shared control
[13]. Multi-modal conditions are common to many real world applications, such
as search and rescue robots navigating disaster zones, teleoperated robots
facing communication degradation, and assistive driving technologies. In [11,
13], we introduced a novel approach called generalized shared control (GSC)
that simultaneously optimizes autonomy objectives (e.g., safety and efficiency)
and operator-autonomy agreement under multimodal conditions; this optimality
prevents such unsafe shared control. In this paper, we describe those results
in more user friendly language by using illustrations and text.


title: Extended Symmetries at Black Hole Horizons in Generic Dimensions

abstract:
  Recently it has been shown that there is asymptotic BMS-like symmetry
associated with the near-horizon geometry of black holes in three and four
dimensions. In this paper, we show that the presence of such BMS-like symmetry
is a ubiquitous feature for black holes in generic dimensions. For black holes
in $D$ dimensions, the symmetry contains 2 supertranslations and $D-2$
generalized superrotations. The superrotations are found to generate a
generalized Witt-like algebra that was previously noticed in a rather different
construction. In the case of stationary and axisymmetric black holes, we
calculate the surface charges and show that the zero-mode charges are
intimately related to the entropy and angular momenta of the black hole.


title:
Majorana flat bands, chiral Majorana edge states, and unidirectional
  Majorana edge states in noncentrosymmetric superconductors

abstract:
  We study two-dimensional noncentrosymmetric nodal superconductors under
Zeeman field and clarify the field angle dependence of topological properties.
It has been shown that the nodal excitation acquires an excitation gap due to
the Zeeman field perpendicular to anti-symmetric spin-orbit coupling, and then
gapful topological superconductivity is realized. We show that the system
undergoes gapful-gapless transition against tilting of the field. The gapless
phase remains to show a finite band gap and unusual Majorana edge states in
between the bulk bands. The Majorana edge states naturally propagate in a same
direction between oppositely-oriented edges. We elucidate relations of such
unidirectional Majorana edge states with chiral edge states in the gapful
topological superconducting phase and previously studied Majorana flat bands at
zero Zeeman field. A compact formula of topological invariants characterizing
the edge states is given. The gapful-gapless topological phase transition and
associated evolution of Majorana states are demonstrated in a model for
$D+p$-wave superconductivity. Experimental realization in recently fabricated
cuprate heterostructures and heavy fermion thin films is discussed.


title: Topological Entropy, Entropy points and shadowing

abstract:
  In this note we study some properties of topological entropy for non-compact
non-metrizable spaces. We prove that if a uniformly continuous self-map $f$ of
a uniform space has topological shadowing property then the map $f$ has
positive uniform entropy, which extends the similar known result for
homeomorphisms on compact metric spaces having shadowing property.


title:
Level functions of quadratic differentials, signed measures, and the
  Strebel property

abstract:
  In this paper, motivated by the classical notion of a Strebel qua- dratic
differential on a compact Riemann surface without boundary, we in- troduce
several classes of quadratic differentials (called non-chaotic, gradient, and
positive gradient) which possess some properties of Strebel differentials and
appear in applications. We discuss the relation between gradient differen-
tials and special signed measures supported on their set of critical
trajectories. We provide a characterisation of gradient differentials for which
there exists a positive measure in the latter class.


title:
Critical quench dynamics of random quantum spin chains: Ultra-slow
  relaxation from initial order and delayed ordering from initial disorder

abstract:
  By means of free fermionic techniques combined with multiple precision
arithmetic we study the time evolution of the average magnetization,
$\overline{m}(t)$, of the random transverse-field Ising chain after global
quenches. We observe different relaxation behaviors for quenches starting from
different initial states to the critical point. Starting from a fully ordered
initial state, the relaxation is logarithmically slow described by
$\overline{m}(t) \sim \ln^a t$, and in a finite sample of length $L$ the
average magnetization saturates at a size-dependent plateau $\overline{m}_p(L)
\sim L^{-b}$; here the two exponents satisfy the relation $b/a=\psi=1/2$.
Starting from a fully disordered initial state, the magnetization stays at zero
for a period of time until $t=t_d$ with $\ln t_d \sim L^{\psi}$ and then starts
to increase until it saturates to an asymptotic value $\overline{m}_p(L) \sim
L^{-b'}$, with $b'\approx 1.5$. For both quenching protocols, finite-size
scaling is satisfied in terms of the scaled variable $\ln t/L^{\psi}$.
Furthermore, the distribution of long-time limiting values of the magnetization
shows that the typical and the average values scale differently and the average
is governed by rare events. The non-equilibrium dynamical behavior of the
magnetization is explained through semi-classical theory.


title: A Graph-based Push Service Platform

abstract:
  It is well known that learning customers' preference and making
recommendations to them from today's information-exploded environment is
critical and non-trivial in an on-line system. There are two different modes of
recommendation systems, namely pull-mode and push-mode. The majority of the
recommendation systems are pull-mode, which recommend items to users only when
and after users enter Application Market. While push-mode works more actively
to enhance or re-build connection between Application Market and users. As one
of the most successful phone manufactures,both the number of users and apps
increase dramatically in Huawei Application Store (also named Hispace Store),
which has approximately 0.3 billion registered users and 1.2 million apps until
2016 and whose number of users is growing with high-speed. For the needs of
real scenario, we establish a Push Service Platform (shortly, PSP) to discover
the target user group automatically from web-scale user operation log data with
an additional small set of labelled apps (usually around 10 apps),in Hispace
Store. As presented in this work,PSP includes distributed storage layer,
application layer and evaluation layer. In the application layer, we design a
practical graph-based algorithm (named A-PARW) for user group discovery, which
is an approximate version of partially absorbing random walk. Based on I mode
of A-PARW, the effectiveness of our system is significantly improved, compared
to the predecessor to presented system, which uses Personalized Pagerank in its
application layer.


title: Finite size scaling study of a two parameter percolation model

abstract:
  A two parameter percolation model with nucleation and growth of finite
clusters is developed taking the initial seed concentration \rho and a growth
parameter g as two tunable parameters. Percolation transition is determined by
the final static configuration of spanning clusters. A finite size scaling
theory for such transition is developed and numerically verified. The scaling
functions are found to depend on both g and \rho. The singularities at the
critical growth probability gc of a given \rho are described by appropriate
critical exponents. The values of the critical exponents are found to be same
as that of the original percolation at all values of \rho at the respective gc
. The model then belongs to the same universality class of percolation for the
whole range of \rho.


title:
Inertial-Based Scale Estimation for Structure from Motion on Mobile
  Devices

abstract:
  Structure from motion algorithms have an inherent limitation that the
reconstruction can only be determined up to the unknown scale factor. Modern
mobile devices are equipped with an inertial measurement unit (IMU), which can
be used for estimating the scale of the reconstruction. We propose a method
that recovers the metric scale given inertial measurements and camera poses. In
the process, we also perform a temporal and spatial alignment of the camera and
the IMU. Therefore, our solution can be easily combined with any existing
visual reconstruction software. The method can cope with noisy camera pose
estimates, typically caused by motion blur or rolling shutter artifacts, via
utilizing a Rauch-Tung-Striebel (RTS) smoother. Furthermore, the scale
estimation is performed in the frequency domain, which provides more robustness
to inaccurate sensor time stamps and noisy IMU samples than the previously used
time domain representation. In contrast to previous methods, our approach has
no parameters that need to be tuned for achieving a good performance. In the
experiments, we show that the algorithm outperforms the state-of-the-art in
both accuracy and convergence speed of the scale estimate. The accuracy of the
scale is around $1\%$ from the ground truth depending on the recording. We also
demonstrate that our method can improve the scale accuracy of the Project
Tango's build-in motion tracking.


title:
Strongly Interacting p-wave Fermi Gas in Two-Dimensions: Universal
  Relations and Breathing Mode

abstract:
  The contact is an important concept that characterizes the universal
properties of a strongly interacting quantum gas. It appears in both
thermodynamic (energy, pressure, etc.) and dynamic quantities (radio-frequency
and Bragg spectroscopies, etc.) of the system. Very recently, the concept of
contact has been extended to higher partial waves, in particular, the p-wave
contacts have been experimentally probed in recent experiment. So far
discussions on p-wave contacts have been limited to three-dimensions. In this
paper, we generalize the p-wave contacts to two-dimensions and derive a series
of universal relations, including the adiabatic relations, high momentum
distribution, virial theorem and pressure relation. At high temperature and low
density limit, we calculated the p-wave contacts explicitly using virial
expansion. A formula which directly connects the shift of the breathing mode
frequency and the p-wave contacts are given in a harmonically trapped system.
Finally, we also derive the relationships between interaction parameters in
three and two dimensional Fermi gas and discuss possible experimental
realization of two dimensional Fermi gas with p-wave interactions.


title: Degree sum conditions for graphs to have proper connection number 2

abstract:
  A path $P$ in an edge-colored graph $G$ is a \emph{proper path} if no two
adjacent edges of $P$ are colored with the same color. The graph $G$ is
\emph{proper connected} if, between every pair of vertices, there exists a
proper path in $G$. The \emph{proper connection number} $pc(G)$ of a connected
graph $G$ is defined as the minimum number of colors to make $G$ proper
connected. In this paper, we study the degree sum condition for a general graph
or a bipartite graph to have proper connection number 2. First, we show that if
$G$ is a connected noncomplete graph of order $n\geq 5$ such that
$d(x)+d(y)\geq \frac{n}{2}$ for every pair of nonadjacent vertices $x,y\in
V(G)$, then $pc(G)=2$ except for three small graphs on 6, 7 and 8 vertices. In
addition, we obtain that if $G$ is a connected bipartite graph of order $n\geq
4$ such that $d(x)+d(y)\geq \frac{n+6}{4}$ for every pair of nonadjacent
vertices $x,y\in V(G)$, then $pc(G)=2$. Examples are given to show that the
above conditions are best possible.


title: Transmit design for MIMO wiretap channel with a malicious jammer

abstract:
  In this paper, we consider the transmit design for multi-input multi-output
(MIMO) wiretap channel including a malicious jammer. We first transform the
system model into the traditional three-node wiretap channel by whitening the
interference at the legitimate user. Additionally, the eavesdropper channel
state information (ECSI) may be fully or statistically known, even unknown to
the transmitter. Hence, some strategies are proposed in terms of different
levels of ECSI available to the transmitter in our paper. For the case of
unknown ECSI, a target rate for the legitimate user is first specified. And
then an inverse water-filling algorithm is put forward to find the optimal
power allocation for each information symbol, with a stepwise search being used
to adjust the spatial dimension allocated to artificial noise (AN) such that
the target rate is achievable. As for the case of statistical ECSI, several
simulated channels are randomly generated according to the distribution of
ECSI. We show that the ergodic secrecy capacity can be approximated as the
average secrecy capacity of these simulated channels. Through maximizing this
average secrecy capacity, we can obtain a feasible power and spatial dimension
allocation scheme by using one dimension search. Finally, numerical results
reveal the effectiveness and computational efficiency of our algorithms.


title:
Deep Quantization: Encoding Convolutional Activations with Deep
  Generative Model

abstract:
  Deep convolutional neural networks (CNNs) have proven highly effective for
visual recognition, where learning a universal representation from activations
of convolutional layer plays a fundamental problem. In this paper, we present
Fisher Vector encoding with Variational Auto-Encoder (FV-VAE), a novel deep
architecture that quantizes the local activations of convolutional layer in a
deep generative model, by training them in an end-to-end manner. To incorporate
FV encoding strategy into deep generative models, we introduce Variational
Auto-Encoder model, which steers a variational inference and learning in a
neural network which can be straightforwardly optimized using standard
stochastic gradient method. Different from the FV characterized by conventional
generative models (e.g., Gaussian Mixture Model) which parsimoniously fit a
discrete mixture model to data distribution, the proposed FV-VAE is more
flexible to represent the natural property of data for better generalization.
Extensive experiments are conducted on three public datasets, i.e., UCF101,
ActivityNet, and CUB-200-2011 in the context of video action recognition and
fine-grained image classification, respectively. Superior results are reported
when compared to state-of-the-art representations. Most remarkably, our
proposed FV-VAE achieves to-date the best published accuracy of 94.2% on
UCF101.


title:
Kinetic Field Theory: Effects of momentum correlations on the cosmic
  density-fluctuation power spectrum

abstract:
  In earlier work, we have developed a Kinetic Field Theory (KFT) for
cosmological structure formation and showed that the non-linear
density-fluctuation power spectrum known from numerical simulations can be
reproduced quite well even if particle interactions are taken into account to
first order only. Besides approximating gravitational interactions, we had to
truncate the initial correlation hierarchy of particle momenta at the second
order. Here, we substantially simplify KFT. We show that its central object,
the free generating functional, can be factorized, taking the full hierarchy of
momentum correlations into account. The factors appearing in the generating
functional, which we identify as non-linearly evolved density-fluctuation power
spectra, have a universal form and can thus be tabulated for fast access in
perturbation schemes.
  In this paper, we focus on a complete evaluation of the free generating
functional of KFT, not including particle interactions yet. This implies that
the non-linearly evolved power spectra contain a damping term which reflects
that structures are being wiped out at late times by free streaming. Once
particle interactions will be taken into account, they will compensate this
damping. If we suppress this damping in a way suggested by the
fluctuation-dissipation relations of KFT, our results show that the complete
hierarchy of initial momentum correlations is responsible for a large part of
the characteristic non-linear deformation and the mode transport in the
density-fluctuation power spectrum. Without any adjustable parameters, KFT
accurately reproduces the scale at which non-linear evolution sets in.
  Finally, we further develop perturbation theory based on the factorization of
the generating functional and propose a diagrammatic scheme for the
perturbation terms.


title: A possible giant planet orbiting the cataclysmic variable LX Ser

abstract:
  LX Ser is a deeply eclipsing cataclysmic variable with an orbital period of
$0.^d 1584325$. Sixty two new eclipse times were determined by our observations
and the AAVSO International Data base. Combining all available eclipse times,
we analyzed the O-C behavior of LX Ser. We found that the O-C diagram of LX Ser
shows a sinusoidal oscillation with a period of 22.8 yr and an amplitude of
0.00035 days. Two mechanisms (i.e., the Applegate mechanism and the light
travel time effect) are applied to explain the cyclic modulation. We found that
the Applegate mechanism is difficult to explain the cyclic oscillation in the
orbital period. Therefore, the cyclic period change is most likely to be caused
by the light travel time effect due to the presence of a third body. The mass
of the tertiary component was determined to be $M_3\sim7.5 M_{Jup}$. We
supposed that the tertiary companion is plausible a giant planet. The stability
of the giant planet was checked, and we found that the multiple system is
stable.


title: Conservation laws and integral relations for the Boussinesq equation

abstract:
  We are concerned with conservation laws and integral relations associated
with rational solutions of the Boussinesq equation, a soliton equation solvable
by inverse scattering which was first introduced by Boussinesq in 1871. The
rational solutions are logarithmic derivatives of a polynomial, are
algebraically decaying and have a similar appearance to rogue-wave solutions of
the focusing nonlinear Schr\"{o}dinger equation. For these rational solutions
the constants of motion associated with the conserved quantities are zero and
they have some interesting integral relations which depend on the total degree
of the associated polynomial.


title: On the existence of Ulrich bundles on geometrically ruled surfaces

abstract:
  Let $S$ be a geometrically ruled surface with invariant $e$ on a curve $C$.
We deal with Ulrich line bundles and $\mu$-stable special Ulrich bundles of
rank $2$ on $S$ when $e\ge0$, slightly extending a recent result due to M.
Aprodu, L. Costa and R.M. Mir\'o-Roig. If $C$ is elliptic, we also prove that
$S$ always supports Ulrich bundles of rank at most $2$, without any restriction
on $e$. Finally, we show that in many cases $S$ supports families of dimension
$p$ of pairwise non-isomorphic, indecomposable, Ulrich bundles for arbitrary
large $p$.


title: Relativistic Jets in Active Galactic Nuclei und Microquasars

abstract:
  Collimated outflows (jets) appear to be a ubiquitous phenomenon associated
with the accretion of material onto a compact object. Despite this ubiquity,
many fundamental physics aspects of jets are still poorly understood and
constrained. These include the mechanism of launching and accelerating jets,
the connection between these processes and the nature of the accretion flow,
and the role of magnetic fields; the physics responsible for the collimation of
jets over tens of thousands to even millions of gravitational radii of the
central accreting object; the matter content of jets; the location of the
region(s) accelerating particles to TeV (possibly even PeV and EeV) energies
(as evidenced by gamma-ray emission observed from many jet sources) and the
physical processes responsible for this particle acceleration; the radiative
processes giving rise to the observed multi-wavelength emission; and the
topology of magnetic fields and their role in the jet collimation and particle
acceleration processes. This chapter reviews the main knowns and unknowns in
our current understanding of relativistic jets, in the context of the main
model ingredients for Galactic and extragalactic jet sources. It discusses
aspects specific to active Galactic nuclei (especially blazars) and
microquasars, and then presents a comparative discussion of similarities and
differences between them.


title:
Direct observation of the M2 phase with its Mott transition in a VO$_2$
  film

abstract:
  In VO$_2$, the explicit origin of the insulator-to-metal transition is still
disputable between Peierls and Mott insulators. Along with the controversy, its
second monoclinic (M2) phase has received considerable attention due to the
presence of electron correlation in undimerized vanadium ions. However, the
origin of the M2 phase is still obscure. Here, we study a granular VO$_2$ film
using conductive atomic force microscopy and Raman scattering. Upon the
structural transition from monoclinic to rutile, we observe directly an
intermediate state showing the coexistence of monoclinic M1 and M2 phases. The
conductivity near the grain boundary in this regime is six times larger than
that of the grain core, producing a donut-like landscape. Our results reveal an
intra-grain percolation process, indicating that VO$_2$ with the M2 phase is a
Mott insulator.


title: Model Confidence Bounds for Variable Selection

abstract:
  In this article, we introduce the concept of model confidence bounds (MCB)
for variable selection in the context of nested models. Similarly to the
endpoints in the familiar confidence interval for parameter estimation, the MCB
identifies two nested models (upper and lower confidence bound models)
containing the true model at a given level of confidence. Instead of trusting a
single selected model obtained from a given model selection method, the MCB
proposes a group of nested models as candidates and the MCB's width and
composition enable the practitioner to assess the overall model selection
uncertainty. A new graphical tool --- the model uncertainty curve (MUC) --- is
introduced to visualize the variability of model selection and to compare
different model selection procedures. The MCB methodology is implemented by a
fast bootstrap algorithm that is shown to yield the correct asymptotic coverage
under rather general conditions. Our Monte Carlo simulations and real data
examples confirm the validity and illustrate the advantages of the proposed
method.


title: Graph-Based Manifold Frequency Analysis for Denoising

abstract:
  We propose a new framework for manifold denoising based on processing in the
graph Fourier frequency domain, derived from the spectral decomposition of the
discrete graph Laplacian. Our approach uses the Spectral Graph Wavelet
transform in order to per- form non-iterative denoising directly in the graph
frequency domain, an approach inspired by conventional wavelet-based signal
denoising methods. We theoretically justify our approach, based on the fact
that for smooth manifolds the coordinate information energy is localized in the
low spectral graph wavelet sub-bands, while the noise affects all frequency
bands in a similar way. Experimental results show that our proposed manifold
frequency denoising (MFD) approach significantly outperforms the state of the
art denoising meth- ods, and is robust to a wide range of parameter selections,
e.g., the choice of k nearest neighbor connectivity of the graph.


title:
Naming the Pain in Requirements Engineering: A Design for a Global
  Family of Surveys and First Results from Germany

abstract:
  For many years, we have observed industry struggling in defining a high
quality requirements engineering (RE) and researchers trying to understand
industrial expectations and problems. Although we are investigating the
discipline with a plethora of empirical studies, they still do not allow for
empirical generalisations. To lay an empirical and externally valid foundation
about the state of the practice in RE, we aim at a series of open and
reproducible surveys that allow us to steer future research in a problem-driven
manner. We designed a globally distributed family of surveys in joint
collaborations with different researchers and completed the first run in
Germany. The instrument is based on a theory in the form of a set of hypotheses
inferred from our experiences and available studies. We test each hypothesis in
our theory and identify further candidates to extend the theory by correlation
and Grounded Theory analysis. In this article, we report on the design of the
family of surveys, its underlying theory, and the full results obtained from
Germany with participants from 58 companies. The results reveal, for example, a
tendency to improve RE via internally defined qualitative methods rather than
relying on normative approaches like CMMI. We also discovered various RE
problems that are statistically significant in practice. For instance, we could
corroborate communication flaws or moving targets as problems in practice. Our
results are not yet fully representative but already give first insights into
current practices and problems in RE, and they allow us to draw lessons learnt
for future replications. Our results obtained from this first run in Germany
make us confident that the survey design and instrument are well-suited to be
replicated and, thereby, to create a generalisable empirical basis of RE in
practice.


title:
A Fair Relay Selection Scheme for a DF Cooperative Network With
  Spatially Random Relays

abstract:
  A new, fair relay selection scheme is proposed for a dual-hop
decode-and-forward network with randomly-distributed relays. Most of the
reported works in the literature achieve fairness at the expense of degrading
the outage probability performance. In addition, they often assume that the
number and locations of the relays are known. In contrast, the proposed scheme
achieves fairness in a random field of relays without deteriorating the outage
probability performance. In this scheme, each relay maintains a countdown timer
whose initial value is a function of the relay location and a tunable parameter
which controls the level of fairness. The optimum value of this parameter is
evaluated in an offline manner so as to achieve fairness by making the average
powers consumed by the relays as close as possible. An exact analytical
expression is derived for the average power consumed by each relay. This
expression is then used to show the superiority of the proposed scheme over
opportunistic relaying and random relay selection schemes.


title: New examples of extremal positive linear maps

abstract:
  New families of nonnegative biquadratic forms that have 8, 9 or 10 real zeros
in $\mathbb{P}^2\times \mathbb{P}^2$ are constructed. These are the first
examples with 8, 9 or 10 real zeros. It is known that nonnegative biquadratic
forms with finitely many real zeros can have at most 10 zeros; our examples
show that the upper bound is obtained. Such biquadratic forms define positive
linear maps on real symmetric $3\times 3$ matrices that are not completely
positive. Our constructions are explicit, and moreover we are able to determine
which of the examples are extremal. We extend the examples to positive maps on
complex matrices and find families of extreme rays in the cone of positive
maps.


title:
A photon observed by the SEDA-FIB detector on the arrival of the
  gravitational wave

abstract:
  We reported a photon detection at the arrival time of the gravitational wave
on December 26th, 2015. According to the LIGO-Virgo collaboration, the
gravitational wave was produced by the merging process of the two black holes.
The merged time was determined at 03:38:53.6 UT on December 26th. At
03:38:54.05 GPS time, one of the detectors of SEDA-FIB on board the
International Space Station (ISS) detected a photon, arriving from the
direction of Corona Australis near the Galactic Bulge (GB). The energy of the
photon was about (35+-7) MeV. A 3.0 sigma level detection of the photon is
discussed.


title: Constrained Pure Nash Equilibria in Polymatrix Games

abstract:
  We study the problem of checking for the existence of constrained pure Nash
equilibria in a subclass of polymatrix games defined on weighted directed
graphs. The payoff of a player is defined as the sum of nonnegative rational
weights on incoming edges from players who picked the same strategy augmented
by a fixed integer bonus for picking a given strategy. These games capture the
idea of coordination within a local neighbourhood in the absence of globally
common strategies. We study the decision problem of checking whether a given
set of strategy choices for a subset of the players is consistent with some
pure Nash equilibrium or, alternatively, with all pure Nash equilibria. We
identify the most natural tractable cases and show NP or coNP-completness of
these problems already for unweighted DAGs.


title:
Connecting Harbours. A comparison of traffic networks across ancient and
  medieval Europe

abstract:
  Ancient and medieval harbours connected via navigable and terrestrial routes
could be interpreted as elements of complex traffic networks. Based on evidence
from three projects in Priority Programme 1630 (Fossa Carolina, Inland harbours
in Central Europe and Byzantine harbours on the Balkan coasts) we present a
pioneer study to apply concepts and tools of network theory on archaeological
and on written evidence as well as to integrate this data into different
network models. Our diachronic approach allows for an analysis of the temporal
and spatial dynamics of webs of connectivity with a focus on the 1st millennium
AD. The combination of case studies on various spatial scales as well as from
regions of inland and maritime navigation (Central Europe respectively the Seas
around the Balkans) allows for the identification of structural similarities
respectively difference between pre-modern traffic systems across Europe. The
contribution is a first step towards further adaptions of tools of network
analysis as an instrument for the connection and comparison of data across the
projects of Priority Programme 1630.


title: Could FRB 131104 Originate from the Merger of Binary Neutron Stars?

abstract:
  Recently, DeLaunay et al. (2016) discovered a gamma-ray transient, Swift
J0644.5-5111, associated with the fast radio burst (FRB) 131104. They also
reported follow-up broadband observations beginning two days after the FRB and
provided upper limits on a putative afterglow of this transient. In this paper,
we show that if such a transient drives a relativistic shock as in a
cosmological gamma-ray burst (GRB), these upper limits are consistent with an
environment of which density is much less than that of an interstellar medium
but typical for the outskirts' density of a galaxy when the typical values of
three microphysical parameters of the shock are taken. This appears to be
inconsistent with the catastrophic event models in which the central engine of
Swift J0644.5-5111 is surrounded by an interstellar medium, but together with
the properties of the gamma-ray transient, favors the binary neutron star
merger origin. We further constrain the physical parameters of the postmerger
object by assuming that Swift J0644.5-5111 results from internal dissipation of
a spinning-down pulsar wind, and we find that the postmerger object is an
ultra-strongly magnetized, very rapidly rotating pulsar. This merger event
should have given birth to a gravitational wave burst, an FRB, and a short GRB
or an extended X-ray/gamma-ray emission if a relativistic jet of the GRB is
missed. Such "triplets" would be testable in the near future with the advanced
LIGO and Virgo gravitational-wave observatories.


title:
Domain wall profiles in Co/Ir$_n$/Pt(111) ultrathin films: influence of
  the Dzyaloshinskii-Moriya interaction

abstract:
  We perform a study of domain walls in Co/Ir$_n$/Pt(111) (n = 0,1,...,6) films
by a combined approach of first-principles calculations and spin dynamics
simulations. We determine the tensorial exchange interactions and the magnetic
anisotropies for the Co overlayer in both FCC and HCP geometries, depending on
the number of Ir buffer layers. We find strong ferromagnetic nearest-neighbor
isotropic exchange interactions between the Co atoms and an out-of-plane
magnetic anisotropy for the films in FCC geometry. Our simulations show that
the magnetic domain walls are of N\'eel type, and their rotational sense
(chirality) is changed upon the insertion of an Ir buffer layer as compared to
the pristine Co/Pt(111) system. Our spin dynamics simulations indicate a
twisting of the spins with respect to the planar domain wall profile on the
triangular lattice. We discuss this domain wall twisting using symmetry
arguments and in terms of an appropriate micromagnetic continuum model
considering extra energy terms compared to the available literature.


title: Single Top Quark Production Measurements in CMS

abstract:
  The CMS experiment has measured the electroweak production of top quark in
different singly production modes: t-, tW- and s-channel. Recent results on
inclusive and differential cross section measurements of t-channel at 13 TeV
and of the fiducial cross section at 8 TeV are shown. The search for single top
quark production in s-channel at 7 and 8 TeV as well as the search for
associated production of Z boson and single top are presented. All measurements
are in agreement with the Standard Model prediction and no sign of new physics
is observed.


title:
Hierarchical Neural Representation of Dreamed Objects Revealed by Brain
  Decoding with Deep Neural Network Features

abstract:
  Dreaming is generally thought to be generated by spontaneous brain activity
during sleep with patterns common to waking experience. This view is supported
by a recent study demonstrating that dreamed objects can be predicted from
brain activity during sleep using statistical decoders trained with
stimulus-induced brain activity. However, it remains unclear whether and how
visual image features associated with dreamed objects are represented in the
brain. In this study, we used a deep neural network (DNN) model for object
recognition as a proxy for hierarchical visual feature representation, and DNN
features for dreamed objects were analyzed with brain decoding of fMRI data
collected during dreaming. The decoders were first trained with
stimulus-induced brain activity labeled with the feature values of the stimulus
image from multiple DNN layers. The decoders were then used to decode DNN
features from the dream fMRI data, and the decoded features were compared with
the averaged features of each object category calculated from a large-scale
image database. We found that the feature values decoded from the dream fMRI
data positively correlated with those associated with dreamed object categories
at mid- to high-level DNN layers. Using the decoded features, the dreamed
object category could be identified at above-chance levels by matching them to
the averaged features for candidate categories. The results suggest that
dreaming recruits hierarchical visual feature representations associated with
objects, which may support phenomenal aspects of dream experience.