title: Parallel Level set algorithm with MPI and accelerated on GPU

abstract:
  Level set method has been used to capture interface motion. Narrow band
algorithm is applied to localize the solving of level-set PDE on global domain
to a tube around interface. Due to the unknown evolving interface, narrow band
algorithm brings load balance problem for parallelizing computing. This work
presents a tool for evenly distributing work loads on CPUs. On the other hand,
numerically solving level-set PDE only needs simple operations but on large
grid points. This work also presents a GPU acceleration for solving level-set
PDE using finite difference method.


title: Cosmology with weak-lensing peak counts

abstract:
  Weak gravitational lensing (WL) causes distortions of galaxy images and
probes massive structures on large scales, allowing us to understand the
late-time evolution of the Universe. One way to extract the cosmological
information from WL is to use peak statistics. Peaks are tracers of massive
halos and therefore probe the mass function. They retain non-Gaussian
information and have already been shown as a promising tool to constrain
cosmology. In this work, we develop a new model to predict WL peak counts. The
model generates fast simulations based on halo sampling and selects peaks from
the derived lensing maps. This approach has three main advantages. First, the
model is very fast: only several seconds are required to perform a realization.
Second, including realistic conditions is straightforward. Third, the model
provides the full distribution information because of its stochasticity. We
show that our model agrees well with N-body simulations. Then, we study the
impacts of the cosmology-dependent covariance on constraints and explore
different parameter inference methods. A special focus is put on approximate
Bayesian computation (ABC), an accept-reject sampler without the need to
estimate the likelihood. We show that ABC is able to yield robust constraints
with much reduced time costs. Several filtering techniques are studied to
improve the extraction of multiscale information. Finally, the new model is
applied to the CFHTLenS, KiDS DR1/2, and DES SV data sets. Our preliminary
results agree with the Planck constraints assuming the Lambda-CDM model.
Overall, this thesis forges an innovative tool for future WL surveys. The
manuscript provides a brief review on WL peak counts.


title:
Non-negative matrix factorization for self-calibration of photometric
  redshift scatter in weak lensing surveys

abstract:
  Photo-z error is one of the major sources of systematics degrading the
accuracy of weak lensing cosmological inferences. Zhang et al. (2010) proposed
a self-calibration method combining galaxy-galaxy correlations and galaxy-shear
correlations between different photo-z bins. Fisher matrix analysis shows that
it can determine the rate of photo-z outliers at a level of 0.01-1% merely
using photometric data and do not rely on any prior knowledge. In this paper,
we develop a new algorithm to implement this method by solving a constrained
nonlinear optimization problem arising in the self-calibration process. Based
on the techniques of fixed-point iteration and non-negative matrix
factorization, the proposed algorithm can efficiently and robustly reconstruct
the scattering probabilities between the true-z and photo-z bins. The algorithm
has been tested extensively by applying it to mock data from simulated stage IV
weak lensing projects. We find that the algorithm provides a successful
recovery of the scatter rates at the level of 0.01-1%, and the true mean
redshifts of photo-z bins at the level of 0.001, which may satisfy the
requirements in future lensing surveys.


title:
The 1.1 mm Continuum Survey of the Small Magellanic Cloud: Physical
  Properties and Evolution of the Dust-selected Clouds

abstract:
  The first 1.1 mm continuum survey toward the Small Magellanic Cloud (SMC) was
performed using the AzTEC instrument installed on the ASTE 10-m telescope. This
survey covered 4.5 deg$^2$ of the SMC with $1\sigma$ noise levels of $5-12$ mJy
beam$^{-1}$, and 44 extended objects were identified. The 1.1 mm extended
emission has good spatial correlation with $Herschel$ 160 $\mathrm{\mu m}$,
indicating that the origin of the 1.1 mm extended emission is thermal emission
from a cold dust component. We estimated physical properties using the 1.1 mm
and filtered $Herschel$ data (100, 160, 250, 350, and 500 $\mathrm{\mu m}$).
The 1.1 mm objects show dust temperatures of $17-45$ K and gas masses of
$4\times10^3-3\times10^5~M_\odot$, assuming single-temperature thermal emission
from the cold dust with an emissivity index, $\beta$, of 1.2 and a gas-to-dust
ratio of 1000. These physical properties are very similar to those of giant
molecular clouds (GMCs) in our galaxy and the Large Magellanic Cloud. The 1.1
mm objects also displayed good spatial correlation with the $Spitzer$ 24
$\mathrm{\mu m}$ and CO emission, suggesting that the 1.1 mm objects trace the
dense gas regions as sites of massive star formation. The dust temperature of
the 1.1 mm objects also demonstrated good correlation with the 24 $\mathrm{\mu
m}$ flux connected to massive star formation. This supports the hypothesis that
the heating source of the cold dust is mainly local star-formation activity in
the 1.1 mm objects. The classification of the 1.1 mm objects based on the
existence of star-formation activity reveals the differences in the dust
temperature, gas mass, and radius, which reflects the evolution sequence of
GMCs.


title:
Finite-distance corrections to the gravitational bending angle of light
  in the strong deflection limit

abstract:
  Continuing work initiated in an earlier publication [Ishihara, Suzuki, Ono,
Kitamura, Asada, Phys. Rev. D {\bf 94}, 084015 (2016) ], we discuss a method of
calculating the bending angle of light in a static, spherically symmetric and
asymptotically flat spacetime, especially by taking account of the finite
distance from a lens object to a light source and a receiver. For this purpose,
we use the Gauss-Bonnet theorem to define the bending angle of light, such that
the definition can be valid also in the strong deflection limit. Finally, this
method is applied to Schwarzschild spacetime in order to discuss also possible
observational implications. The proposed corrections for Sgr A$^{\ast}$ for
instance are able to amount to $\sim 10^{-5}$ arcseconds for some parameter
range, which may be within the capability of near-future astronomy, while also
the correction for the Sun in the weak field limit is $\sim 10^{-5}$
arcseconds.


title:
Giant Nernst effect in the incommensurate charge density wave state of
  P4W12O44

abstract:
  We report the study of Nernst effect in quasi-low dimensional tungsten bronze
P4W12O44 showing a sequence of Peierls instabilities. We demonstrate that both
condensation of the electronic carriers in the CDW state and the existence of
high-mobility electrons and holes originating from the small pockets remaining
in the incompletely nested Fermi surface give rise to a Nernst effect of a
magnitude similar to that observed in heavy fermion compounds.


title: Chaotic edge density fluctuations in the Alcator C-Mod tokamak

abstract:
  Analysis of the time series obtained with the O-Mode reflectometer (Rhodes et
al 1997 Plasma Phys. and Control. Fusion 40 (1998) 493-510) and the gas puff
imaging (Cziegler, I. et al 2010 Phys. of Plasmas 17, No. 5 (2010) 056120)
systems on the Alcator C-Mod tokamak reveals that the turbulent edge density
fluctuations are chaotic. Supporting evidence for this conclusion includes: the
observation of exponential power spectra (which is associated with
Lorentzian-shaped pulses in the time series), the population of the
corresponding Bandt-Pompe probability distributions (Bandt and Pompe 2002 Phys.
Rev. Lett. 88 174102), and the location of the signal on the complexity-entropy
plane (C-H plane) (Rosso et al 2007 Phys. Rev. Lett. 99, 154102 (2007)). The
classification of edge turbulence as chaotic opens the door for further work to
understand the underlying process and the impact on turbulent transport.


title:
Optimal performance of generalized heat engines with finite-size baths
  of arbitrary multiple conserved quantities beyond i.i.d. scaling

abstract:
  In quantum thermodynamics, effects of finiteness of the baths have been less
considered. In particular, there is no general theory which focuses on
finiteness of the baths of multiple conserved quantities. Then, we investigate
how the optimal performance of generalized heat engines with multiple conserved
quantities alters in response to the size of the baths. In the context of
general theories of quantum thermodynamics, the size of the baths has been
given in terms of the number of identical copies of a system, which does not
cover even such a natural scaling as the volume. In consideration of the
asymptotic extensivity, we deal with a generic scaling of the baths to
naturally include the volume scaling. Based on it, we derive a bound for the
performance of generalized heat engines reflecting finite-size effects of the
baths, which we call fine-grained generalized Carnot bound. We also construct a
protocol to achieve the optimal performance of the engine given by this bound.
Finally, applying the obtained general theory, we deal with simple examples of
generalized heat engines. As for an example of non-i.i.d.~scaling and multiple
conserved quantities, we investigate a heat engine with two baths composed of
an ideal gas exchanging particles, where the volume scaling is applied. The
result implies that the mass of the particle explicitly affects the performance
of this engine with finite-size baths.


title: Airy-averaged gradient corrections for two-dimensional fermion gases

abstract:
  Building on the discussion in PRA 93, 042510 (2016), we present a systematic
derivation of gradient corrections to the kinetic-energy functional and the
one-particle density, in particular for two-dimensional systems. We derive the
leading gradient corrections from a semiclassical expansion based on Wigner's
phase space formalism and demonstrate that the semiclassical kinetic-energy
density functional at zero temperature cannot be evaluated unambiguously. In
contrast, a density-potential functional description that effectively
incorporates interactions provides unambiguous gradient corrections. Employing
an averaging procedure that involves Airy functions, thereby partially
resumming higher-order gradient corrections, we facilitate a smooth transition
of the particle density into the classically forbidden region of arbitrary
smooth potentials. We find excellent agreement of the semiclassical
Airy-averaged particle densities with the exact densities for very low but
finite temperatures, illustrated for a Fermi gas with harmonic potential
energy. We furthermore provide criteria for the applicability of the
semiclassical expansions at low temperatures. Finally, we derive a well-behaved
ground-state kinetic-energy functional, which improves on the Thomas-Fermi
approximation.


title:
A numerical approach to determine mutant invasion fitness and
  evolutionary singular strategies

abstract:
  We propose a numerical approach to study the invasion fitness of a mutant and
to determine evolutionary singular strategies in evolutionary structured models
in which the competitive exclusion principle holds. Our approach is based on a
dual representation, which consists of the modelling of the small size mutant
population by a stochastic model and the computation of its corresponding
deterministic model. The use of the deterministic model greatly facilitates the
numerical determination of the feasibility of invasion as well as the
convergence-stability of the evolutionary singular strategy. Our approach
combines standard adaptive dynamics with the link between the mutant survival
criterion in the stochastic model and the sign of the eigenvalue in the
corresponding deterministic model. We present our method in the context of a
mass-structured individual-based chemostat model. We exploit a previously
derived mathematical relationship between stochastic and deterministic
representations of the mutant population in the chemostat model to derive a
general numerical method for analyzing the invasion fitness in the stochastic
models. Our method can be applied to the broad class of evolutionary models for
which a link between the stochastic and deterministic invasion fitnesses can be
established.


title:
From traffic and pedestrian follow-the-leader models with reaction time
  to first order convection-diffusion flow models

abstract:
  In this work, we derive first order continuum traffic flow models from a
microscopic delayed follow-the-leader model. Those are applicable in the
context of vehicular traffic flow as well as pedestrian traffic flow. The
microscopic model is based on an optimal velocity function and a reaction time
parameter. The corresponding macroscopic formulations in Eulerian or Lagrangian
coordinates result in first order convection-diffusion equations. More
precisely, the convection is described by the optimal velocity while the
diffusion term depends on the reaction time. A linear stability analysis for
homogeneous solutions of both continuous and discrete models are provided. The
conditions match the ones of the car-following model for specific values of the
space discretization. The behavior of the novel model is illustrated thanks to
numerical simulations. Transitions to collision-free self-sustained stop-and-go
dynamics are obtained if the reaction time is sufficiently large. The results
show that the dynamics of the microscopic model can be well captured by the
macroscopic equations. For non--zero reaction times we observe a scattered
fundamental diagram. The scattering width is compared to real pedestrian and
road traffic data.


title: Optimal Hardy inequalities for Schr\"odinger operators on graphs

abstract:
  For a given subcritical discrete Schr\"odinger operator $H$ on a weighted
infinite graph $X$, we construct a Hardy-weight $w$ which is optimal in the
following sense. The operator $H - \lambda w$ is subcritical in $X$ for all
$\lambda < 1$, null-critical in $X$ for $\lambda = 1$, and supercritical near
any neighborhood of infinity in $X$ for any $\lambda > 1$. Our results rely on
a criticality theory for Schr\"odinger operators on general weighted graphs.


title:
Theory and Tools for the Conversion of Analog to Spiking Convolutional
  Neural Networks

abstract:
  Deep convolutional neural networks (CNNs) have shown great potential for
numerous real-world machine learning applications, but performing inference in
large CNNs in real-time remains a challenge. We have previously demonstrated
that traditional CNNs can be converted into deep spiking neural networks
(SNNs), which exhibit similar accuracy while reducing both latency and
computational load as a consequence of their data-driven, event-based style of
computing. Here we provide a novel theory that explains why this conversion is
successful, and derive from it several new tools to convert a larger and more
powerful class of deep networks into SNNs. We identify the main sources of
approximation errors in previous conversion methods, and propose simple
mechanisms to fix these issues. Furthermore, we develop spiking implementations
of common CNN operations such as max-pooling, softmax, and batch-normalization,
which allow almost loss-less conversion of arbitrary CNN architectures into the
spiking domain. Empirical evaluation of different network architectures on the
MNIST and CIFAR10 benchmarks leads to the best SNN results reported to date.


title: Data Gathering from Path Constrained Mobile Sensors Using Data MULE

abstract:
  In Wireless Sensor Network (WSN) sensor nodes are deployed to sense useful
data from environment. Sensors are energy-constrained devices. To prolong the
sensor network lifetime, now a days mobile robots (sometimes refer as data
sink, data mules, or data collectors) are used for collecting the sensed data
from the sensors. In this environment sensor nodes directly transfer their
sensed data to the data mules. Sensed data are sometime time sensitive;
therefore, the data should be collected within a predefined period. Hence,
depending on the speed of the data mules the trajectory lengths of the data
mules have upper limits. In this paper an approximation algorithm is proposed
for collecting data from the mobile sensors using mobile data collectors


title:
Neutron background measurements at China Jinping underground laboratory
  with a Bonner Multi-sphere Spectrometer

abstract:
  The neutron background spectrum from thermal neutron to 20 MeV fast neutron
was measured at the first experimental hall of China Jinping underground
laboratory with a Bonner multi-sphere spectrometer. The measurement system was
validated by a Cf252 source and inconformity was corrected. Due to micro charge
discharge, the dataset was screened and background from the steel of the
detectors was estimated by MC simulation. Based on genetic algorithm we
obtained the energy distribution of the neutron and the total flux of neutron
was (2.69 +/-1.02) *10^-5 cm^-2s^-1


title:
Negative mass hydrodynamics in a Spin-Orbit--Coupled Bose-Einstein
  Condensate

abstract:
  A negative effective mass can be realized in quantum systems by engineering
the dispersion relation. A powerful method is provided by spin-orbit coupling,
which is currently at the center of intense research efforts. Here we measure
an expanding spin-orbit coupled Bose-Einstein condensate whose dispersion
features a region of negative effective mass. We observe a range of dynamical
phenomena, including the breaking of parity and of Galilean covariance,
dynamical instabilities, and self-trapping. The experimental findings are
reproduced by a single-band Gross-Pitaevskii simulation, demonstrating that the
emerging features - shockwaves, soliton trains, self-trapping, etc. - originate
from a modified dispersion. Our work also sheds new light on related phenomena
in optical lattices, where the underlying periodic structure often complicates
their interpretation.


title: Joint Bayesian Gaussian discriminant analysis for speaker verification

abstract:
  State-of-the-art i-vector based speaker verification relies on variants of
Probabilistic Linear Discriminant Analysis (PLDA) for discriminant analysis. We
are mainly motivated by the recent work of the joint Bayesian (JB) method,
which is originally proposed for discriminant analysis in face verification. We
apply JB to speaker verification and make three contributions beyond the
original JB. 1) In contrast to the EM iterations with approximated statistics
in the original JB, the EM iterations with exact statistics are employed and
give better performance. 2) We propose to do simultaneous diagonalization (SD)
of the within-class and between-class covariance matrices to achieve efficient
testing, which has broader application scope than the SVD-based efficient
testing method in the original JB. 3) We scrutinize similarities and
differences between various Gaussian PLDAs and JB, complementing the previous
analysis of comparing JB only with Prince-Elder PLDA. Extensive experiments are
conducted on NIST SRE10 core condition 5, empirically validating the
superiority of JB with faster convergence rate and 9-13% EER reduction compared
with state-of-the-art PLDA.


title:
$B_s \to \mu \tau$ and $h \to \mu \tau$ decays in the general two Higgs
  doublet model

abstract:
  Inspired by the recent measurement of the $h \to \mu \tau$ decays by the CMS
collaboration at the LHC, we study the lepton flavour-violating (LFV) $B_s \to
\mu \tau$ decays in the general two Higgs doublet model. Those LFV interactions
could accommodate the present deviation of the muon anomalous magnetic moment
and also predict the LFV $\tau$ decay processes such as $\tau \to \mu \mu \mu$
and $\tau \to \mu \gamma$. We find that the $B_s \to \mu \tau$ decay rates
should be sizable with above experimental conditions in the framework of our
model. These processes are expected to be observed at the colliders such as
LHCb and Belle-II in the future.


title:
Signal Detection under Short-Interval Sampling of Continuous Waveforms
  for Optical Wireless Scattering Communication

abstract:
  In optical wireless scattering communication, received signal in each symbol
interval is captured by a photomultiplier tube (PMT) and then sampled through
very short but finite interval sampling. The resulting samples form a signal
vector for symbol detection. The upper and lower bounds on transmission rate of
such a processing system are studied. It is shown that the gap between two
bounds approaches zero as the thermal noise and shot noise variances approach
zero. The maximum a posteriori (MAP) signal detection is performed and a low
computational complexity receiver is derived under piecewise polynomial
approximation. Meanwhile, the threshold based signal detection is also studied,
where two threshold selection rules are proposed based on the detection error
probability and the Kullback-Leibler (KL) distance. For the latter, it is shown
that the KL distance is not sensitive to the threshold selection for small shot
and thermal noise variances, and thus the threshold can be selected among a
wide range without significant loss from the optimal KL distance. The
performances of the transmission rate bounds, the signal detection, and the
threshold selection approaches are evaluated by the numerical results.


title:
Parameter Estimation Under Model Uncertainties by Iterative Covariance
  Approximation

abstract:
  We propose a novel iterative algorithm for estimating a deterministic but
unknown parameter vector in the presence of model uncertainties. This iterative
algorithm is based on a system model where an overall noise term describes
both, the measurement noise and the noise resulting from the model
uncertainties. This overall noise term is a function of the true parameter
vector, allowing for an iterative algorithm. The proposed algorithm can be
applied on structured as well as unstructured models and it outperforms prior
art algorithms for a broad range of applications.


title: Best Widely Linear Unbiased Estimator for Real Valued Parameter Vectors

abstract:
  For classical estimation with an underlying linear model the best linear
unbiased estimator (BLUE) is usually utilized for estimating the deterministic
but unknown parameter vector. In the case of real valued parameter vectors but
complex valued measurement matrices and noise vectors, the BLUE results in
complex valued estimates, introducing a systematic error. In recent years
widely linear estimators have been investigated for complex estimation. In this
work a novel widely linear classical estimator is derived which incorporates
the knowledge that the parameter vector is real valued. The proposed estimator
is unbiased in the classical sense and it outperforms the BLUE and the best
widely linear unbiased estimator (BWLUE) in terms of the variances of the
vector estimator's elements.


title: Learning to Hash-tag Videos with Tag2Vec

abstract:
  User-given tags or labels are valuable resources for semantic understanding
of visual media such as images and videos. Recently, a new type of labeling
mechanism known as hash-tags have become increasingly popular on social media
sites. In this paper, we study the problem of generating relevant and useful
hash-tags for short video clips. Traditional data-driven approaches for tag
enrichment and recommendation use direct visual similarity for label transfer
and propagation. We attempt to learn a direct low-cost mapping from video to
hash-tags using a two step training process. We first employ a natural language
processing (NLP) technique, skip-gram models with neural network training to
learn a low-dimensional vector representation of hash-tags (Tag2Vec) using a
corpus of 10 million hash-tags. We then train an embedding function to map
video features to the low-dimensional Tag2vec space. We learn this embedding
for 29 categories of short video clips with hash-tags. A query video without
any tag-information can then be directly mapped to the vector space of tags
using the learned embedding and relevant tags can be found by performing a
simple nearest-neighbor retrieval in the Tag2Vec space. We validate the
relevance of the tags suggested by our system qualitatively and quantitatively
with a user study.


title:
Spatial Pyramid Convolutional Neural Network for Social Event Detection
  in Static Image

abstract:
  Social event detection in a static image is a very challenging problem and
it's very useful for internet of things applications including automatic photo
organization, ads recommender system, or image captioning. Several publications
show that variety of objects, scene, and people can be very ambiguous for the
system to decide the event that occurs in the image. We proposed the spatial
pyramid configuration of convolutional neural network (CNN) classifier for
social event detection in a static image. By applying the spatial pyramid
configuration to the CNN classifier, the detail that occurs in the image can
observe more accurately by the classifier. USED dataset provided by Ahmad et
al. is used to evaluate our proposed method, which consists of two different
image sets, EiMM, and SED dataset. As a result, the average accuracy of our
system outperforms the baseline method by 15% and 2% respectively.


title:
Evolution of a semidiscrete system modeling the scattering of acoustic
  waves by a piezoelectric solid

abstract:
  We consider a model problem of the scattering of linear acoustic waves in
free homogeneous space by an elastic solid. The stress tensor in the solid
combines the effect of a linear dependence of strains with the influence of an
existing electric field. The system is closed using Gauss's law for the
associated electric displacement. Well-posedness of the system is studied by
its reformulation as a first order in space and time differential system with
help of an elliptic lifting operator. We then proceed to studying a
semidiscrete formulation, corresponding to an abstract Finite Element
discretization in the electric and elastic fields, combined with an abstract
Boundary Element approximation of a retarded potential representation of the
acoustic field. The results obtained with this approach improve estimates
obtained with Laplace domain techniques. While numerical experiments
illustrating convergence of a fully discrete version of this problem had
already been published, we demonstrate some properties of the full model with
some simulations for the two dimensional case.


title:
Spin reorientation in NdFe$_{0.5}$Mn$_{0.5}$O$_{3}$: Neutron scattering
  and \emph{Ab-initio} study

abstract:
  The structural, magnetic, and electronic properties of
NdFe$_{0.5}$Mn$_{0.5}$O$_3$ have been studied in detail using bulk
magnetization, neutron/x-ray diffraction and first principles density
functional theory calculations. The material crystallizes in the orthorhombic
$Pbnm$ structure, where both Mn and Fe occupy the same crystallographic site
($4b$).
  Mn/Fe sublattice of the compound orders in to a G-type antiferromagnetic
phase close to 250\,K where the magnetic structure belongs to ${\Gamma}_{1}$
irreducible representation with spins aligned along the crystallographic $b$
direction. This is unconventional in the sense that most of the orthoferrites
and orthochromites order in the ${\Gamma}_{4}$ representation below the
N\'{e}el temperature.This magnetic structure then undergoes a complete spin
reorientation transition with temperature in the range 75\,K$\gtrsim$ T
$\gtrsim$ 25\,K where the magnetic structure exists as a sum of two irreducible
representations (${\Gamma}_{1}$+${\Gamma}_{2}$) as seen from neutron
diffraction measurements. At 6\,K, the magnetic structure belongs entirely to
${\Gamma}_{2}$ representation with spins aligned antiferromagnetically along
the crystallographic $c$ direction having a small ferromagnetic component
($F_x$). The unusual spin reorientation and correlation between magnetic ground
state and electronic structure have been investigated using first principles
calculations within GGA+U and GGA+U+SO formalisms.


title: Green OFDMA Resource Allocation in Cache-Enabled CRAN

abstract:
  Cloud radio access network (CRAN), in which remote radio heads (RRHs) are
deployed to serve users in a target area, and connected to a central processor
(CP) via limited-capacity links termed the fronthaul, is a promising candidate
for the next-generation wireless communication systems. Due to the
content-centric nature of future wireless communications, it is desirable to
cache popular contents beforehand at the RRHs, to reduce the burden on the
fronthaul and achieve energy saving through cooperative transmission. This
motivates our study in this paper on the energy efficient transmission in an
orthogonal frequency division multiple access (OFDMA)-based CRAN with multiple
RRHs and users, where the RRHs can prefetch popular contents. We consider a
joint optimization of the user-SC assignment, RRH selection and transmit power
allocation over all the SCs to minimize the total transmit power of the RRHs,
subject to the RRHs' individual fronthaul capacity constraints and the users'
minimum rate constraints, while taking into account the caching status at the
RRHs. Although the problem is non-convex, we propose a Lagrange duality based
solution, which can be efficiently computed with good accuracy. We compare the
minimum transmit power required by the proposed algorithm with different
caching strategies against the case without caching by simulations, which show
the significant energy saving with caching.


title:
Dynamics in quantum Ising chain driven by inhomogeneous transverse
  magnetization

abstract:
  We study the dynamics caused by transport of transverse magnetization in one
dimensional transverse Ising chain at zero temperature. We observe that a class
of initial states having product structure in fermionic momentum-space and
satisfying certain criteria, produce spatial variation in transverse
magnetization. Starting from such a state, we obtain the transverse
magnetization analytically and then observe its dynamics in presence of a
homogeneous constant field $\Gamma$. In contradiction with general expectation,
whatever be the strength of the field, the magnetization of the system does not
become homogeneous even after infinite time. At each site, the dynamics is
associated with oscillations having two different timescales. The envelope of
the larger timescale oscillation decays algebraically with an exponent which is
invariant for all such special initial states. The frequency of this
oscillation varies differently with external field in ordered and disordered
phases. The local magnetization after infinite time also characterizes the
quantum phase transition.


title:
Antenna, Spectrum and Capacity trade-off for Cloud-RAN Massive
  Distributed MIMO over Next Generation PONs

abstract:
  We propose a cost-optimal antenna vs. spectrum resource allocation strategy
for mobile 5G MD-MIMO over Next-Generation PONs. Comparing wavelength overlay
and shared wavelength approaches, split-PHY leads to solutions with higher
mobile capacity than fronthaul.


title:
Arbitrary-Lagrangian-Eulerian discontinuous Galerkin schemes with a
  posteriori subcell finite volume limiting on moving unstructured meshes

abstract:
  We present a new family of high order accurate fully discrete one-step
Discontinuous Galerkin (DG) finite element schemes on moving unstructured
meshes for the solution of nonlinear hyperbolic PDE in multiple space
dimensions, which may also include parabolic terms in order to model
dissipative transport processes. High order piecewise polynomials are adopted
to represent the discrete solution at each time level and within each spatial
control volume of the computational grid, while high order of accuracy in time
is achieved by the ADER approach. In our algorithm the spatial mesh
configuration can be defined in two different ways: either by an isoparametric
approach that generates curved control volumes, or by a piecewise linear
decomposition of each spatial control volume into simplex sub-elements. Our
numerical method belongs to the category of direct
Arbitrary-Lagrangian-Eulerian (ALE) schemes, where a space-time conservation
formulation of the governing PDE system is considered and which already takes
into account the new grid geometry directly during the computation of the
numerical fluxes. Our new Lagrangian-type DG scheme adopts the novel a
posteriori sub-cell finite volume limiter method, in which the validity of the
candidate solution produced in each cell by an unlimited ADER-DG scheme is
verified against a set of physical and numerical detection criteria. Those
cells which do not satisfy all of the above criteria are flagged as troubled
cells and are recomputed with a second order TVD finite volume scheme. The
numerical convergence rates of the new ALE ADER-DG schemes are studied up to
fourth order in space and time and several test problems are simulated.
Finally, an application inspired by Inertial Confinement Fusion (ICF) type
flows is considered by solving the Euler equations and the PDE of viscous and
resistive magnetohydrodynamics (VRMHD).


title: Triangulating Almost-Complete Graphs

abstract:
  A triangle decomposition of a graph $G$ is a partition of the edges of $G$
into triangles. Two necessary conditions for $G$ to admit such a decomposition
are that $|E(G)|$ is a multiple of three and that the degree of any vertex in
$G$ is even; we call such graphs tridivisible.
  Kirkman's work on Steiner triple systems established that for $G \simeq K_n$,
$G$ admits a triangle decomposition precisely when $G$ is tridivisible. In
1970, Nash-Williams conjectured that tridivisiblity is also sufficient for
"almost-complete" graphs, which for this talk's purposes we interpret as any
graph $G$ on $n$ vertices with $\delta(G) \geq (1 -\epsilon)n, E(G) \geq (1 -
\xi)\binom{n}{2}$ for some appropriately small constants $\epsilon, \xi$.
Nash-Williams conjectured that $\epsilon = \xi =1/4$ would suffice; in 1991,
Gustavsson demonstrated in his dissertation that $\epsilon = \xi < 10^{-24}$
suffices for all $n \equiv 3, 9 \mod 18$, and in 2015 Keevash's work on the
existence conjecture for combinatorial designs established that some value of
$\epsilon$ existed for any $n$.
  In this paper, we prove that for any $\epsilon < \frac{1}{432}$, there is a
constant $\xi$ such that any $G$ with $\delta(G) \geq (1 - \epsilon)n$ and
$|E(G)| \geq (1 - \xi)\binom{n}{2}$ admits such a decomposition, and offer an
algorithm that explicitly constructs such a triangulation. Moreover, we note
that our algorithm runs in polynomial time on such graphs. (This last
observation contrasts with Holyer's result that finding triangle decompositions
in general is a NP-complete problem.)


title:
Solution of the Master Equation for Quantum Brownian Motion given by the
  Schr\"{o}dinger Equation

abstract:
  We consider the master equation of quantum Brownian motion and with the
application of the group invariant transformation we show that there exists a
surface on which the solution of the master equation is given by an autonomous
one-dimensional Schr\"{o}dinger Equation.


title:
On multiple zeta values and finite multiple zeta values of maximal
  height

abstract:
  An explicit formula for the height-one multiple zeta values was proved by
Kaneko and the second author. We give an alternative proof of this result and
its generalization. We also prove its counterpart for the finite multiple zeta
values.


title:
Collective electronic excitation in a trapped ensemble of photogenerated
  dipolar excitons and free holes revealed by inelastic light scattering

abstract:
  Photogenerated excitonic ensembles confined in coupled GaAs quantum wells are
probed by a complementary approach of emission spectroscopy and resonant
inelastic light scattering. Lateral electrostatic trap geometries are used to
create dense systems of spatially indirect excitons and excess holes with
similar densities in the order of 10$^{11}$ cm$^{-2}$. Inelastic light
scattering spectra reveal a very sharp low-lying collective mode that is
identified at an energy of 0.44 meV and a FWHM of only ~50 $\mu$eV. This mode
is interpreted as a plasmon excitation of the excess hole system coupled to the
photogenerated indirect excitons. The emission energy of the indirect excitons
shifts under the application of a perpendicular applied electric field with the
quantum-confined Stark effect unperturbed from the presence of free charge
carriers. Our results illustrate the potential of studying low-lying collective
excitations in photogenerated exciton systems to explore the many-body phase
diagram, related phase transitions, and interaction physics.


title: The Poincar\'e-Hopf Theorem for line fields revisited

abstract:
  A Poincar\'e-Hopf Theorem for line fields with point singularities on
orientable surfaces can be found Hopf's 1956 Lecture Notes on Differential
Geometry. In 1955 Markus presented such a theorem in all dimensions, but
Markus' statement only holds in even dimensions $2k \geq 4$. In 1984 J\"{a}nich
presented a Poincar\'{e}-Hopf theorem for line fields with more complicated
singularities and focussed on the complexities arising in the generalised
setting.
  In this expository note we review the Poincar\'e-Hopf Theorem for line fields
with point singularities, presenting a careful proof which is valid in all
dimensions.


title: Spatio-temporal data mining in ecological and veterinary epidemiology

abstract:
  Understanding the spread of any disease is a highly complex and
interdisciplinary exercise as biological, social, geographic, economic, and
medical factors may shape the way a disease moves through a population and
options for its eventual control or eradication. Disease spread poses a serious
threat in animal and plant health and has implications for ecosystem
functioning and species extinctions as well as implications in society through
food security and potential disease spread in humans. Space-time epidemiology
is based on the concept that various characteristics of the pathogenic agents
and the environment interact in order to alter the probability of disease
occurrence and form temporal or spatial patterns. Epidemiology aims to identify
these patterns and factors, to assess the relevant uncertainty sources, and to
describe disease in the population. Thus disease spread at the population level
differs from the approach traditionally taken by veterinary practitioners that
are principally concerned with the health status of the individual. Patterns of
disease occurrence provide insights into which factors may be affecting the
health of the population, through investigating which individuals are affected,
where are these individuals located and when did they become infected. With the
rapid development of smart sensors, social networks, as well as digital maps
and remotely-sensed imagery spatio-temporal data are more ubiquitous and richer
than ever before. The availability of such large datasets (Big data) poses
great challenges in data analysis. In addition, increased availability of
computing power facilitates the use of computationally-intensive methods for
the analysis of such data. Thus new methods as well as case studies are needed
to understand veterinary and ecological epidemiology. A special issue aimed to
address this topic.


title: The Journal Impact Factor Should Not Be Discarded

abstract:
  The Journal Impact Factor (JIF) has been heavily criticized over decades.
This opinion piece argues that the JIF should not be demonized. It still can be
employed for research evaluation purposes by carefully considering the context
and academic environment.


title: Touchard's Drunkard

abstract:
  Based on Touchard's identity, a simple derivation is given for the
enumeration of the N/S/E/W walks that remain on the north side of the origin.


title: Bayesian analysis of CCDM Models

abstract:
  Creation of Cold Dark Matter (CCDM), in the context of Einstein Field
Equations, leads to negative creation pressure, which can be used to explain
the accelerated expansion of the Universe. In this work we tested six different
spatially flat models for matter creation using statistical tools, at light of
SN Ia data: Akaike Information Criterion (AIC), Bayesian Information Criterion
(BIC) and Bayesian Evidence (BE). These approaches allow to compare models
considering goodness of fit and number of free parameters, penalizing excess of
complexity. We find that JO model is slightly favoured over LJO/$\Lambda$CDM
model, however, neither of these, nor $\Gamma=3\alpha H_0$ model can be
discarded from the current analysis. Three other scenarios are discarded either
from poor fitting, either from excess of free parameters.


title: Introduction to chiral symmetry in QCD

abstract:
  The main aspects of chiral symmetry in QCD are presented. The necessity of
its spontaneous breakdown is explained. Some low-energy theorems are reviewed.
The role of chiral effective Lagrangians in the formulation and realization of
chiral perturbation theory is emphasized. The consequences of the presence of
anomalies are sketched.


title: Scale-chiral symmetry, $\omega$ meson and dense baryonic matter

abstract:
  It is shown that explicitly broken scale symmetry is essential for dense
skyrmion matter in hidden local symmetry theory. Consistency with the vector
manifestation fixed point for the hidden local symmetry of the lowest-lying
vector mesons and the dilaton limit fixed point for scale symmetry in dense
matter is found to require that the anomalous dimension ($\gamma_{G^2}$) of the
gluon field strength tensor squared ($G^2$) that represents the quantum trace
anomaly should be $0 <\gamma_{G^2} <3$.


title: Non-existence of natural states for Abelian Chern-Simons theory

abstract:
  We give an elementary proof that Abelian Chern-Simons theory, described as a
functor from oriented surfaces to C*-algebras, does not admit a natural state.
Non-existence of natural states is thus not only a phenomenon of quantum field
theories on Lorentzian manifolds, but also of topological quantum field
theories formulated in the algebraic approach.


title:
GeP3: A small indirect band gap 2D crystal with high carrier mobility
  and strong interlayer quantum confinement

abstract:
  We propose a two-dimensional crystal which possesses low indirect band gaps
of 0.55 eV (monolayer) and 0.43 eV (bilayer) and high carrier mobilities
similar to those of phosphorene: GeP3. GeP3 has a stable three-dimensional
layered bulk counterpart which is metallic and is known from experiment since
1970. It has a small cleavage energy, which suggests exfoliation of bulk
material as viable means for the preparation of mono- and few-layer materials.
The material shows strong interlayer quantum confinement effects, resulting in
a band gap reduction from mono- to bilayer, and then to a semiconductor-metal
transition between bi- and triple layer. Under biaxial strain, the indirect
band gap can be turned into a direct one. Pronounced light absorption in the
spectral range from ~600 to 1400 nm is predicted for monolayer and bilayer and
promises applications in photovoltaics.


title:
What Lies Beneath the Surface: Topological-Shape Optimization With the
  Kernel-Independent Fast Multipole Method

abstract:
  The paper presents a new method for shape and topology optimization based on
an efficient and scalable boundary integral formulation for elasticity. To
optimize topology, our approach uses iterative extraction of isosurfaces of a
topological derivative. The numerical solution of the elasticity boundary value
problem at every iteration is performed with the boundary element formulation
and the kernel-independent fast multipole method. Providing excellent single
node performance, scalable parallelization and the best available asymptotic
complexity, our method is among the fastest optimization tools available today.
The performance of our approach is studied on few illustrative examples,
including the optimization of engineered constructions for the minimum
compliance and the optimization of the microstructure of a metamaterial for the
desired macroscopic tensor of elasticity.


title: Tropical limit of log-inflection points for planar curves

abstract:
  The paper describes behavior of log-inflection points of curves in
$(\mathbb{C}^*)^2$ under passing to the tropical limit. We show that such
points accumulate by pairs at the midpoints of bounded edges in the limiting
tropical curve. Log-inflection points are points of inflection with respect to
the parallelization of $(\mathbb{C}^*)^2$ given by the multiplicative group
law.


title: Beta-decay properties of neutron-rich rare-earth isotopes

abstract:
  In this paper, beta-decay properties of even-even neutron-rich isotopes in
the rare-earth mass region are studied within a microscopic theoretical
approach based on a proton-neutron quasiparticle random-phase approximation.
The underlying mean field is constructed selfconsistently from a deformed
Hartree-Fock calculation with Skyrme interactions and pairing correlations to
which particle-hole and particle-particle residual interactions are added.
Nuclei in this mass region participate in the astrophysical rapid neutron
capture process and are directly involved in the generation of the rare-earth
peak in the isotopic abundance pattern centered at A=160. The energy
distributions of the Gamow-Teller strength as well as the beta-decay half-lives
and the beta-delayed neutron-emission probabilities are discussed and compared
with the available experimental information and with calculations based on
different approaches.


title: Generic matrix polynomials with fixed rank and fixed degree

abstract:
  The set ${\cal P}^{m\times n}_{r,d}$ of $m \times n$ complex matrix
polynomials of grade $d$ and (normal) rank at most $r$ in a complex $(d+1)mn$
dimensional space is studied. For $r = 1, \dots , \min \{m, n\}-1$, we show
that ${\cal P}^{m\times n}_{r,d}$ is the union of the closures of the $rd+1$
sets of matrix polynomials with rank $r$, degree exactly $d$, and explicitly
described complete eigenstructures. In addition, for the full-rank rectangular
polynomials, i.e. $r= \min \{m, n\}$ and $m \neq n$, we show that ${\cal
P}^{m\times n}_{r,d}$ coincides with the closure of a single set of the
polynomials with rank $r$, degree exactly $d$, and the described complete
eigenstructure. These complete eigenstructures correspond to generic $m \times
n$ matrix polynomials of grade $d$ and rank at most~$r$.


title:
Strong First Order Electroweak Phase Transition in the CP-Conserving
  2HDM Revisited

abstract:
  The discovery of the Higgs boson by the LHC experiments ATLAS and CMS has
marked a milestone for particle physics. Yet, there are still many open
questions that cannot be answered within the Standard Model (SM). For example,
the generation of the observed matter-antimatter asymmetry in the universe
through baryogenesis can only be explained qualitatively in the SM. A simple
extension of the SM compatible with the current theoretical and experimental
constraints is given by the 2-Higgs-Doublet Model (2HDM) where a second Higgs
doublet is added to the Higgs sector. We investigate the possibility of a
strong first order electroweak phase transition in the CP-conserving 2HDM type
I and type II where either of the CP-even Higgs bosons is identified with the
SM-like Higgs boson. The renormalisation that we apply on the loop-corrected
Higgs potential allows us to efficiently scan the 2HDM parameter space and
simultaneously take into account all relevant theoretical and up-to-date
experimental constraints. The 2HDM parameter regions found to be compatible
with the applied constraints and a strong electroweak phase transition are
analysed systematically. Our results show that there is a strong interplay
between the requirement of a strong phase transition and collider phenomenology
with testable implications for searches at the LHC.


title:
Calculations of kaonic nuclei based on chiral meson-baryon coupled
  channel interaction models

abstract:
  We present our latest calculations of $K^-$-nuclear quasi-bound states using
a self-consistent scheme for constructing $K^-$-nuclear potentials from various
subthreshold chirally inspired $\bar{K}N$ scattering amplitudes. We consider
in-medium versions of the scattering amplitudes taking into account Pauli
blocking in the intermediate states. The resulting $K^-$ binding energies as
well as the widths exhibit the same A dependence, however, the binding energies
strongly depend on the model used.


title:
Rigidity theory for $C^*$-dynamical systems and the "Pedersen Rigidity
  Problem"

abstract:
  Let $G$ be a locally compact abelian group. By modifying a theorem of
Pedersen, it follows that actions of $G$ on $C^*$-algebras $A$ and $B$ are
outer conjugate if and only if there is an isomorphism of the crossed products
that is equivariant for the dual actions and preserves the images of $A$ and
$B$ in the multiplier algebras of the crossed products. The rigidity problem
discussed in this paper deals with the necessity of the last condition
concerning the images of $A$ and $B$.
  There is an alternative formulation of the problem: an action of the dual
group $\hat G$ together with a suitably equivariant unitary homomorphism of $G$
give rise to a generalized fixed-point algebra via Landstad's theorem, and a
problem related to the above is to produce an action of $\hat G$ and two such
equivariant unitary homomorphisms of $G$ that give distinct generalized
fixed-point algebras.
  We present several situations where the condition on the images of $A$ and
$B$ is redundant, and where having distinct generalized fixed-point algebras is
impossible. For example, if $G$ is discrete, this will be the case for all
actions of $G$.


title:
Multiple supersonic phase fronts launched at a complex-oxide
  hetero-interface

abstract:
  Selective optical excitation of a substrate lattice can drive phase changes
across hetero-interfaces. This phenomenon is a non-equilibrium analogue of
static strain control in heterostructures and may lead to new applications in
optically controlled phase change devices. Here, we make use of time-resolved
non-resonant and resonant x-ray diffraction to clarify the underlying physics,
and to separate different microscopic degrees of freedom in space and time. We
measure the dynamics of the lattice and that of the charge disproportionation
in NdNiO3, when an insulator-metal transition is driven by coherent lattice
distortions in the LaAlO3 substrate. We find that charge redistribution
propagates at supersonic speeds from the interface into the NdNiO3 film,
followed by a sonic lattice wave. When combined with measurements of magnetic
disordering and of the metal-insulator transition, these results establish a
hierarchy of events for ultrafast control at complex oxide hetero-interfaces.


title: Index theory for improper actions: localization at units

abstract:
  We pursue the study of local index theory for operators of Fourier-integral
type associated to non-proper and non-isometric actions of Lie groupoids,
initiated in a previous work. We introduce the notion of geometric cocycles for
Lie groupoids, which allow to represent fairly general cyclic cohomology
classes of the convolution algebra of Lie groupoids localized at isotropic
submanifolds. Then we compute the image of geometric cocycles localized at
units under the excision map of the fundamental pseudodifferential extension.
As an illustrative example, we prove an equivariant longitudinal index theorem
for a codimension one foliation endowed with a transverse action of the group
of real numbers.


title:
Identifiability issues of age-period and age-period-cohort models of the
  Lee-Carter type

abstract:
  The predominant way of modelling mortality rates is the Lee-Carter model and
its many extensions. The Lee-Carter model and its many extensions use a latent
process to forecast. These models are estimated using a two-step procedure that
causes an inconsistent view on the latent variable. This paper considers
identifiability issues of these models from a perspective that acknowledges the
latent variable as a stochastic process from the beginning. We call this
perspective the plug-in age-period or plug-in age-period-cohort model. Defining
a parameter vector that includes the underlying parameters of this process
rather than its realisations, we investigate whether the expected values and
covariances of the plug-in Lee-Carter models are identifiable. It will be seen,
for example, that even if in both steps of the estimation procedure we have
identifiability in a certain sense it does not necessarily carry over to the
plug-in models.


title:
The 26 December 2001 Solar Eruptive Event Responsible for GLE63. III.
  CME, Shock Waves, and Energetic Particles

abstract:
  The SOL2001-12-26 moderate solar eruptive event (GOES importance M7.1,
microwaves up to 4000 sfu at 9.4 GHz, CME speed 1446 km/s) produced strong
fluxes of solar energetic particles and ground-level enhancement of cosmic-ray
intensity (GLE63). To find a possible reason for the atypically high proton
outcome of this event, we study multi-wavelength images and dynamic radio
spectra and quantitatively reconcile the findings with each other. An
additional eruption probably occurred in the same active region about half an
hour before the main eruption. The latter produced two blast-wave-like shocks
during the impulsive phase. The two shock waves eventually merged around the
radial direction into a single shock traced up to $25R_\odot$ as a halo ahead
of the expanding CME body, in agreement with an interplanetary Type II event
recorded by the Radio and Plasma Wave Investigation (WAVES) experiment on the
Wind spacecraft. The shape and kinematics of the halo indicate an intermediate
regime of the shock between the blast wave and bow shock at these distances.
The results show that i) the shock wave appeared during the flare rise and
could accelerate particles earlier than usually assumed; ii) the particle event
could be amplified by the preceding eruption, which stretched closed structures
above the developing CME, facilitated its lift-off and escape of
flare-accelerated particles, enabled a higher CME speed and stronger shock
ahead; iii) escape of flare-accelerated particles could be additionally
facilitated by reconnection of the flux rope, where they were trapped, with a
large coronal hole; iv) the first eruption supplied a rich seed population
accelerated by a trailing shock wave.


title:
Modified Cholesky Riemann Manifold Hamiltonian Monte Carlo: Exploiting
  Sparsity for Fast Sampling of High-dimensional Targets

abstract:
  Riemann manifold Hamiltonian Monte Carlo (RMHMC) has the potential to produce
high-quality Markov chain Monte Carlo-output even for very challenging target
distributions. To this end, a symmetric positive definite scaling matrix for
RMHMC, which derives, via a modified Cholesky factorization, from the
potentially indefinite negative Hessian of the target log-density is proposed.
The methodology is able to exploit the sparsity of the Hessian, stemming from
conditional independence modeling assumptions, and thus admit fast
implementation of RMHMC even for high-dimensional target distributions.
Moreover, the methodology can exploit log-concave conditional target densities,
often encountered in Bayesian hierarchical models, for faster sampling and more
straight forward tuning. The proposed methodology is compared to alternatives
for some challenging targets, and is illustrated by applying a state space
model to real data.


title:
Efficient Representation of Multidimensional Data over Hierarchical
  Domains

abstract:
  We consider the problem of representing multidimensional data where the
domain of each dimension is organized hierarchically, and the queries require
summary information at a different node in the hierarchy of each dimension.
This is the typical case of OLAP databases. A basic approach is to represent
each hierarchy as a one-dimensional line and recast the queries as
multidimensional range queries. This approach can be implemented compactly by
generalizing to more dimensions the $k^2$-treap, a compact representation of
two-dimensional points that allows for efficient summarization queries along
generic ranges. Instead, we propose a more flexible generalization, which
instead of a generic quadtree-like partition of the space, follows the domain
hierarchies across each dimension to organize the partitioning. The resulting
structure is much more efficient than a generic multidimensional structure,
since queries are resolved by aggregating much fewer nodes of the tree.


title:
Speed of Gravitational Waves from Strongly Lensed Gravitational Waves
  and Electromagnetic Signals

abstract:
  We propose a new model-independent measurement strategy for the propagation
speed of gravitational waves (GWs) based on strongly lensed GWs and their
electromagnetic (EM) counterparts. This can be done in two ways: by comparing
arrival times of GWs and their EM counterparts and by comparing the time delays
between images seen in GWs and their EM counterparts. The lensed GW-EM event is
perhaps the best way to identify an EM counterpart. Conceptually, this method
does not rely on any specific theory of massive gravitons or modified gravity.
Its differential setting (i.e., measuring the difference between time delays in
GW and EM domains) makes it robust against lens modeling details (photons and
GWs travel in the same lensing potential) and against internal time delays
between GW and EM emission acts. It requires, however, that the theory of
gravity is metric and predicts gravitational lensing similar to general
relativity. We expect that such a test will become possible in the era of
third-generation gravitational-wave detectors, when about 10 lensed GW events
would be observed each year. The power of this method is mainly limited by the
timing accuracy of the EM counterpart, which for kilonovae is around $10^4$
s.Thisuncertaintycanbesuppressedbya factor of $\sim 10^{10}$, if strongly
lensed transients of much shorter duration associated with the GW event can be
identified. Candidates for such short transients include short gamma-ray burst
and fast radio bursts.


title: Setting the Foundations for PoP-Based Internet Evolution Models

abstract:
  Developing an evolution model of the Internet has been a long standing
research challenge. Such a model can improve the design and placement of
communication infrastructure, reducing costs and improving users' quality of
experience. While communication infrastructure is tightly coupled to
geographical locations, Internet modelling and forecasting in the last decade
used network elements that are only loosely bounded to any geographical
location. In this paper we set the foundations for developing an evolution
model of the Internet based on the Point of Presence (PoP) level. As PoPs have
a strong geographical grip they can better represent the evolution of the
Internet. We annotate the PoP topologies of the Internet with geographical,
economic and demographic information to achieve an understanding of the
dynamics of the Internet's structure, in order to identify the constitutive
laws of Internet evolution. We identify GDP as the strongest indicator on the
country level, and the size of the TV market as the strongest indicator on the
US metropolitan level. Finally, we draw attention to the limitations of
developing a world-wide evolution model.


title:
A short note on dynamics and degrees of freedom in $2d$ classical
  gravity

abstract:
  We comment on some peculiarities of matter with and without Weyl invariance
coupled to classical $2d$ Einstein-Hilbert gravity for several models, in
particular, related to the counting of degrees of freedom and on the dynamics.
We find that theories where the matter action is Weyl invariant has generically
more degrees of freedom than action without the invariance. This follows from
the Weyl invariance of the metric equations of motion independently of the
invariance of the action. Then, we study another set of models with scalar
fields and show that solutions to the equations of motion are either trivial or
inconsistent. To our knowledge, these aspects of classical $2d$ gravity have
not been put forward and can be interesting to be remembered when using it as a
toy model for $4d$ gravity. The goal of this note is also as a pedagogical
exercise: our results follow from standard methods, but we emphasize more
direct computations.


title:
POLAR: Final Calibration and In-Flight Performance of a Dedicated GRB
  Polarimeter

abstract:
  Gamma-ray polarimetry is a new powerful tool to study the processes
responsible for the emission from astrophysical sources and the environments in
which this emission takes place. Few successful polarimetric measurements have
however been performed thus far in the gamma-ray energy band due to the
difficulties involved. POLAR is a dedicated polarimeter designed to perform
high precision measurements of the polarization of the emission from gamma-ray
burst in the 50-500 keV energy range. This new polarimeter is expected to
detect approximately 50 gamma-ray bursts per year while performing high
precision polarization measurements on approximately 10 bursts per year. The
instrument was launched into lower earth orbit as part of the second Chinese
space lab, the Tiangong-2, on September 15th 2016 and has been taking data
successfully since being switched on one week after. The instrument uses a
segmented scintillator array consisting of 1600 plastic scintillator bars, read
out by 25 flat-panel multi-anode photomultipliers, to measure the Compton
scattering angles of incoming photons. The small segmentation and relatively
large uniform effective area allow the instrument to measure the polarization
of a large number of transient events, such as gamma-ray bursts, with an
unprecedented precision during its two year life-time. The final flight model
underwent detailed calibration prior to launch as well as intensive space
qualification tests, a summary of which will be presented in this paper. The
instrument design will be discussed first followed by an overview of the
on-ground tests, finally the in-orbit behavior as measured during the first
weeks of the mission will be presented.


title: Exploiting re-voting in the Helios election system

abstract:
  Election systems must ensure that representatives are chosen by voters.
Moreover, each voter should have equal influence. Traditionally, this has been
achieved by permitting voters to cast at most one ballot. More recently, this
has been achieved by tallying the last ballot cast by each voter. We show this
is not achieved by the Helios election system, because an adversary can cause a
ballot other than a voter's last to be tallied. Moreover, we show how the
adversary can choose the contents of such a ballot, thus the adversary can
unduly influence the selection of representatives.


title:
A temporal model for quasi-phase matching in high-order harmonic
  generation

abstract:
  We present a model for quasi-phase matching (QPM) in high-order harmonic
generation (HHG). Using a one-dimensional description, we analyze the
time-dependent, ultrafast wave-vector balance to calculate the on-axis harmonic
output versus time, from which we obtain the output pulse energy. Considering,
as an example, periodically patterned argon gas, as may be provided with a grid
in a cluster jet, we calculate the harmonic output during different time
intervals within the drive laser pulse duration. We find that identifying a
suitable single spatial period is not straightforward due to the complex and
ultrafast plasma dynamics that underlies HHG at increased intensities. The
maximum on-axis harmonic pulse energy is obtained when choosing the QPM period
to phase match HHG at the leading edge of the drive laser pulse.


title:
Calculating probabilistic excursion sets and related quantities using
  excursions

abstract:
  The R software package excursions contains methods for calculating
probabilistic excursion sets, contour credible regions, and simultaneous
confidence bands for latent Gaussian stochastic processes and fields. It also
contains methods for uncertainty quantification of contour maps and computation
of Gaussian integrals. This article describes the theoretical and computational
methods used in the package. The main functions of the package are introduced
and two examples illustrate how the package can be used.


title: The Groups $G_{n}^{k}$ and Fundamental Groups of Configuration Spaces

abstract:
  We construct a map from fundamental groups of complements to some plane
configurations to the groups $G_{n}^{k}$ for large $k$. We discuss connection
between the groups $G_{n}^{k}$ for different $G_{n}^{k}$ and their geometric
realization.


title: A priori estimates for water waves with emerging bottom

abstract:
  We study the beach problem for water waves. The case we consider is a compact
fluid domain, where the free surface intersect the bottom along an edge, with a
non-zero contact angle. Using elliptic estimates in domain with edges and a new
equation on the Taylor coefficient, we establish a priori estimates, for angles
smaller than a dimensional constant. Local existence will be derived in a
following paper.


title:
Reactive infiltration: identifying the role of chemical reactions,
  capillarity, viscosity and gravity

abstract:
  A wealth of experimental data indicate that while capillarity controlled
infiltration gives an infiltration length that varies with the square root of
time, reactive infiltration is characterised by a linear relationship between
the two magnitudes. In addition the infiltration rate in the latter is at least
two orders of magnitude greater than in the former.
  This work is addressed to investigate imbibition of a non-wetting, albeit
reactive, liquid into a capillary, within the framework of a simple model that
includes capillarity effects, viscosity and gravity. The capillary radius is
allowed to vary, due to reaction, with both position and time, according to
either an interface or a diffusion law. The model allows for capillary closure
when reaction kinetics dominates imbibition. At short times, and depending on
whether infiltration is capillarity or gravity controlled, the infiltrated
length varies either as the square root or linearly with time. This suggest the
following track for reactive infiltration: i) In most cases, the contact angle
is initially larger than $90^\circ$, ii) after some time, reaction gradually
replaces the interface liquid/preform by the liquid/reaction product interface
and, concomitantly, the contact angle gets closer to $90^\circ$, iii) beyond
that time, gravity triggers infiltration (actually the contact angle does not
need to be smaller than $90^\circ$ for the initiation of infiltration due to
the metallostatic pressure exerted by the liquid metal on top of the porous
preform), iv) thereafter infiltration is controlled by viscosity and gravity,
provided that, due to reaction, the contact angle remains close to that at
which infiltration was initiated.


title:
Experimental Evidences for Static Charge Density Waves in Iron
  Oxy-pnictides

abstract:
  In this Letter we report high-resolution synchrotron X-ray powder diffraction
and transmission electron microscope analysis of Mn-substituted LaFeAsO
samples, demonstrating that a static incommensurate modulated structure
develops across the low-temperature orthorhombic phase, whose modulation
wave-vector depends on the Mn content. The incommensurate structural distortion
is likely originating from a charge-density-wave instability, a periodic
modulation of the density of conduction electrons associated with a modulation
of the atomic positions. Our results add a new component in the physics of
Fe-based superconductors, indicating that the density wave ordering is
charge-driven.


title: Sturm-Liouville operators with matrix distributional coefficients

abstract:
  The paper deals with singular Sturm-Liouville expressions with matrix-valued
distributional coefficients. Due to a suitable regularization, the
corresponding operators are correctly defined as quasi-differentials. Their
resolvent convergence is investigated and all self-adjoint, maximal
dissipative, and maximal accumulative extensions are described in terms of
homogeneous boundary conditions of the canonical form.


title:
Two-body relaxation of spin-polarized fermions in reduced
  dimensionalities near a p-wave Feshbach resonance

abstract:
  We study inelastic two-body relaxation in a spin-polarized ultracold Fermi
gas in the presence of a p-wave Feshbach resonance. It is shown that in reduced
dimensionalities, especially in the quasi-one-dimensional case, the enhancement
of the inelastic rate constant on approach to the resonance is strongly
suppressed compared to three dimensions. This may open promising paths for
obtaining novel many-body states.


title: Corporate Disruption in the Science of Machine Learning

abstract:
  This MSc dissertation considers the effects of the current corporate interest
on researchers in the field of machine learning. Situated within the field's
cyclical history of academic, public and corporate interest, this dissertation
investigates how current researchers view recent developments and negotiate
their own research practices within an environment of increased commercial
interest and funding. The original research consists of in-depth interviews
with 12 machine learning researchers working in both academia and industry.
Building on theory from science, technology and society studies, this
dissertation problematizes the traditional narratives of the neoliberalization
of academic research by allowing the researchers themselves to discuss how
their career choices, working environments and interactions with others in the
field have been affected by the reinvigorated corporate interest of recent
years.


title: Gaussian free fields at the integer quantum Hall plateau transition

abstract:
  In this work we put forward an effective Gaussian free field description of
critical wavefunctions at the transition between plateaus of the integer
quantum Hall effect. To this end, we expound our earlier proposal that powers
of critical wave intensities prepared via point contacts behave as pure scaling
fields obeying an Abelian operator product expansion. Our arguments employ the
framework of conformal field theory and, in particular, lead to a
multifractality spectrum which is parabolic. We also derive a number of old and
new identities that hold exactly at the lattice level and hinge on the
correspondence between the Chalker-Coddington network model and a
supersymmetric vertex model.

categories: cond-mat.dis-nn cond-mat.stat-mech hep-th math-ph math.MP


title:
Observation of dynamics inside an unlabeled live cell using bright-field
  photon microscopy: Evaluation of organelles' trajectories

abstract:
  This article presents an algorithm for the evaluation of organelles'
movements inside of an unmodified live cell. We used a time-lapse image series
obtained using wide-field bright-field photon transmission microscopy as an
algorithm input. The benefit of the algorithm is the application of the R\'enyi
information entropy, namely a variable called a point information gain, which
enables to highlight the borders of the intracellular organelles and to
localize the organelles' centers of mass with the precision of one pixel.


title:
Parsimonious Online Learning with Kernels via Sparse Projections in
  Function Space

abstract:
  Despite their attractiveness, popular perception is that techniques for
nonparametric function approximation do not scale to streaming data due to an
intractable growth in the amount of storage they require. To solve this problem
in a memory-affordable way, we propose an online technique based on functional
stochastic gradient descent in tandem with supervised sparsification based on
greedy function subspace projections. The method, called parsimonious online
learning with kernels (POLK), provides a controllable tradeoff? between its
solution accuracy and the amount of memory it requires. We derive conditions
under which the generated function sequence converges almost surely to the
optimal function, and we establish that the memory requirement remains finite.
We evaluate POLK for kernel multi-class logistic regression and kernel
hinge-loss classification on three canonical data sets: a synthetic Gaussian
mixture model, the MNIST hand-written digits, and the Brodatz texture database.
On all three tasks, we observe a favorable tradeoff of objective function
evaluation, classification performance, and complexity of the nonparametric
regressor extracted the proposed method.


title:
Upper Bound of Bayesian Generalization Error in Non-negative Matrix
  Factorization

abstract:
  Non-negative matrix factorization (NMF) is a new knowledge discovery method
that is used for text mining, signal processing, bioinformatics, and consumer
analysis. However, its basic property as a learning machine is not yet
clarified, as it is not a regular statistical model, resulting that theoretical
optimization method of NMF has not yet established. In this paper, we study the
real log canonical threshold of NMF and give an upper bound of the
generalization error in Bayesian learning. The results show that the
generalization error of the matrix factorization can be made smaller than
regular statistical models if Bayesian learning is applied.


title: Vicinity-Driven Paragraph and Sentence Alignment for Comparable Corpora

abstract:
  Parallel corpora have driven great progress in the field of Text
Simplification. However, most sentence alignment algorithms either offer a
limited range of alignment types supported, or simply ignore valuable clues
present in comparable documents. We address this problem by introducing a new
set of flexible vicinity-driven paragraph and sentence alignment algorithms
that 1-N, N-1, N-N and long distance null alignments without the need for
hard-to-replicate supervised models.


title: Log-convex and Stieltjes moment sequences

abstract:
  We show that Stieltjes moment sequences are infinitely log-convex, which
parallels a famous result that (finite) P\'olya frequency sequences are
infinitely log-concave. We introduce the concept of $q$-Stieltjes moment
sequences of polynomials and show that many well-known polynomials in
combinatorics are such sequences. We provide a criterion for linear
transformations and convolutions preserving Stieltjes moment sequences. Many
well-known combinatorial sequences are shown to be Stieltjes moment sequences
in a unified approach and therefore infinitely log-convex, which in particular
settles a conjecture of Chen and Xia about the infinite log-convexity of the
Schr\"oder numbers. We also list some interesting problems and conjectures
about the log-convexity and the Stieltjes moment property of the (generalized)
Ap\'ery numbers.


title: Ergodicity of gyrofluid edge localised ideal ballooning modes

abstract:
  The magnetic field structure associated with edge localised ideal ballooning
mode (ELM) bursts is analysed by nonlinear gyrofluid computation. The linear
growth phase is characterised by the formation of small scale magnetic islands.
Ergodic magnetic field regions develop near the end of the linear phase when
the instability starts to perturb the equilibrium profiles. The nonlinear
blow-out gives rise to an ergodisation of the entire edge region. The
time-dependent level of ergodicity is determined in terms of the mean radial
displacement of a magnetic field line. The ergodicity decreases again during
the nonlinear turbulent phase of the blow-out in dependence on the degrading
plasma beta in the collapsing plasma pedestal profile.


title:
Interplay of the inverse proximity effect and magnetic field in
  out-of-equilibrium single-electron devices

abstract:
  The magnetic field is shown to affect significantly non-equilibrium
quasiparticle (QP) distributions under conditions of inverse proximity effect
on the remarkable example of a single-electron hybrid turnstile. This effect
suppresses the gap in the superconducting leads in the vicinity of turnstile
junctions with a Coulomb blockaded island, thus, trapping hot QPs in this
region. Applied magnetic field creates additional QP traps in the form of
vortices or regions with reduced superconducting gap in the leads resulting in
release of QPs away from junctions. We present clear experimental evidence of
such interplay of the inverse proximity effect and a magnetic field revealing
itself in the superconducting gap enhancement in a magnetic field as well as in
significant improvement of the turnstile characteristics. The observed
interplay of the inverse proximity effect and external magnetic field, and its
theoretical explanation in the context of QP overheating are important for
various superconducting and hybrid nanoelectronic devices, which find
applications in quantum computation, photon detection and quantum metrology.


title:
Ba8CoNb6O24: a spin-1/2 triangular-lattice Heisenberg antiferromagnet in
  the 2D limit

abstract:
  The perovskite Ba8CoNb6O24 comprises equilateral effective spin-1/2 Co2+
triangular layers separated by six non-magnetic layers. Susceptibility,
specific heat and neutron scattering measurements combined with
high-temperature series expansions and spin-wave calculations confirm that
Ba8CoNb6O24 is basically a twodimensional (2D) magnet with no detectable spin
anisotropy and no long-range magnetic ordering down to 0.06 K. In other words,
Ba8CoNb6O24 is very close to be a realization of the paradigmatic spin-1/2
triangular Heisenberg model, which is not expected to exhibit symmetry breaking
at finite temperature according to the Mermin and Wagner theorem.


title:
Information Extraction with Character-level Neural Networks and Free
  Noisy Supervision

abstract:
  We present an architecture for information extraction from text that augments
an existing parser with a character-level neural network. The network is
trained using a measure of consistency of extracted data with existing
databases as a form of noisy supervision. Our architecture combines the ability
of constraint-based information extraction systems to easily incorporate domain
knowledge and constraints with the ability of deep neural networks to leverage
large amounts of data to learn complex features. Boosting the existing parser's
precision, the system led to large improvements over a mature and highly tuned
constraint-based production information extraction system used at Bloomberg for
financial language text.


title: Rigidity for critical points in the Levy-Gromov inequality

abstract:
  The Levy-Gromov inequality states that round spheres have the least
isoperimetric profile (normalized by total volume) among Riemannian manifolds
with a fixed positive lower bound on the Ricci tensor. In this note we study
critical metrics corresponding to the Levy-Gromov inequality and prove that, in
two-dimensions, this criticality condition is quite rigid, as it characterizes
round spheres and projective planes.


title:
On stability of generalised systems of difference equation with
  non-consistent initial conditions

abstract:
  For given non-consistent initial conditions, we study the stability of a
class of generalised linear systems of difference equations with constant
coefficients and taking into account that the leading coefficient can be a
singular matrix. We focus on the optimal solutions of the system and derive
easily testable conditions for stability.


title:
Gyrofluid computation of magnetic perturbation effects on turbulence and
  edge localized bursts

abstract:
  The effects of non-axisymmetric resonant magnetic perturbation fields (RMPs)
on saturated drift-wave turbulence and on ballooning mode bursts in the edge
pedestal of tokamak plasmas are investigated by numerical simulations with a
nonlinear six-moment electromagnetic gyrofluid model including zonal profile
evolution. The vacuum RMP fields are screened by plasma response currents, so
that magnetic transport by perturbed parallel motion is not significantly
changed. Radial transport of both particles and heat is dominated by turbulent
convection even for large RMP amplitudes, where formation of stationary
convective structures leads to edge profile degradation. Modelling of ideal
ballooning mode unstable edge profiles for single bursts including RMP fields
causes resonant mode locking and destabilization.


title: Observation of three-particle complexes in WS$_2$ monolayers

abstract:
  Atomically thin semiconducting transition-metal dichalcogenides provide novel
insights into the physics of many-body effects mediated by Coulomb
interactions. Here, we report on temperature-dependent ($T$ = 7-295 K)
reflectance contrast and photoluminescence studies of three-particle complexes
in n-doped WS$_2$ monolayers. In low-temperature reflectance contrast spectra
we observe distinct resonances of the neutral exciton, negative trion and
exciton bound to a donor (X, X$^-$ and X$^D$). For temperatures above 80 K,
reflectance contrast signatures of the X$^D$ disappear, whereas the X$^-$
remains detectable up to 240 K, despite the fact that the X$^D$ signal is more
red-shifted from the neutral exciton than that of the X$^-$. This experimental
observation underlines that in WS$_2$ the dissociation energy of X$^-$
considerably exceeds (factor of 2.5) that of X$^D$. In the laser-power
dependent photoluminescence experiments, performed at room temperature, we
demonstrate the control of the intensity ratio and energy position of the X and
X$^-$ lines, which allows us to evaluate the trion binding energy. Moreover, we
demonstrate that the room-temperature PL is sensitive to the environmental gas
(ambient, N$_2$, He).


title: Local existence of MHD contact discontinuities

abstract:
  We prove the local-in-time existence of solutions with a contact
discontinuity of the equations of ideal compressible magnetohydrodynamics (MHD)
for 2D planar flows provided that the Rayleigh-Taylor sign condition $[\partial
p/\partial N]<0$ on the jump of the normal derivative of the pressure is
satisfied at each point of the initial discontinuity. MHD contact
discontinuities are characteristic discontinuities with no flow across the
discontinuity for which the pressure, the magnetic field and the velocity are
continuous whereas the density and the entropy may have a jump. This paper is a
natural completion of our previous analysis [Morando A., Trakhinin Y.,
Trebeschi P., J. Differential Equations 258:2531--2571, 2015] where the
well-posedness in Sobolev spaces of the linearized problem was proved under the
Rayleigh-Taylor sign condition satisfied at each point of the unperturbed
discontinuity. The proof of the resolution of the nonlinear problem given in
the present paper follows from a suitable tame a priori estimate in Sobolev
spaces for the linearized equations and a Nash-Moser iteration.


title:
Hamilton-Jacobi approach for quasi-exponential inflation: predictions
  and constraints after Planck 2015 results

abstract:
  In the present work we study the consequences of considering an inflationary
universe model in which the Hubble rate has a quasi-exponential dependence in
the inflaton field, given by $H(\phi)=H_{inf}\exp
\left[\frac{\frac{\phi}{m_p}}{p\left(1+\frac{\phi}{m_p}\right)}\right]$. We
analyze the inflation dynamics under the Hamilton-Jacobi approach, which allows
us to consider $H(\phi)$, rather than $V(\phi)$, as the fundamental quantity to
be specified. By comparing the theoretical predictions of the model together
with the allowed contour plots in the $n_s-r$ plane and the amplitude of
primordial scalar perturbations from the latest Planck data, the parameters
charactering this model are constrained. The model predicts values for the
tensor-to-scalar ratio $r$ and for the running of the scalar spectral index
$dn_s/ d\ln k$ consistent with the current bounds imposed by Planck, and we
conclude that the model is viable.


title:
Topography preserved microwave plasma etching for top-down layer
  engineering in MoS2 and other van der Waals materials

abstract:
  A generic and universal layer engineering strategy for van der Waals (vW)
materials, scalable and compatible with the current semiconductor technology is
of paramout importance in realizing all-two-dimensional logic circuits and move
beyond the silicon scaling limit. In this letter, we demonstrate a scalable and
highly controllable microwave plasma based layer engineering strategy for MoS2
and other vW materials. Using this technique we etch MoS2 flakes layer-by-layer
starting from arbitrary thickness and area down to the mono- or the few-layer
limit. From Raman spectroscopy, atomic force microscopy, photoluminescence
spectroscopy, scanning electron microscopy and transmission electron
microscopy, we confirm that the structural and morphological properties of the
material have not been compromised. The process preserves the pre-etch layer
topography and yields a smooth and pristine-like surface. We explore the
electrical properties utilising a field effect transistor geometry and find
that the mobility values of our samples are comparable to those of the pristine
ones. The layer removal does not involve any reactive gasses or chemical
reactions and relies on breaking the weak inter-layer vW interaction making it
a generic technique for a wide spectrum of layered materials and
heterostructures. We demonstrate the wide applicability of the technique by
extending it to other systems such as Graphene, h-BN and WSe2. In addition,
using the microwave plasma in combination with standard lithography, we
illustrate a lateral patterning scheme for device fabrication.


title:
The hierarchical generalized linear model and the bootstrap estimator of
  the error of prediction of loss reserves in a non-life insurance company

abstract:
  This paper presents the hierarchical generalized linear model (HGLM) for loss
reserving in a non-life insurance company. Because in this case the error of
prediction is expressed by a complex analytical formula, the error bootstrap
estimator is proposed instead. Moreover, the bootstrap procedure is used to
obtain full information about the error by applying quantiles of the absolute
prediction error. The full R code is available on the Github
https://github.com/woali/BootErrorLossReserveHGLM.


title:
An IMEX-RK scheme for capturing similarity solutions in the
  multidimensional Burgers' equation

abstract:
  In this paper we introduce a new, simple and efficient numerical scheme for
the implementation of the freezing method for capturing similarity solutions in
partial differential equations. The scheme is based on an IMEX-Runge-Kutta
approach for a method of lines (semi-)discretization of the freezing partial
differential algebraic equation (PDAE). We prove second order convergence for
the time discretization at smooth solutions in the ODE-sense and we present
numerical experiments that show second order convergence for the full
discretization of the PDAE. As an example serves the multi-dimensional Burgers'
equation. By considering very different sizes of viscosity, Burgers' equation
can be considered as a prototypical example of general coupled
hyperbolic-parabolic PDEs. Numerical experiments show that our method works
perfectly well for all sizes of viscosity, suggesting that the scheme is indeed
suitable for capturing similarity solutions in general hyperbolic-parabolic
PDEs by direct forward simulation with the freezing method.


title: Massive MIMO with Imperfect Channel Covariance Information

abstract:
  This work investigates the impact of imperfect statistical information in the
uplink of massive MIMO systems. In particular, we first show why covariance
information is needed and then propose two schemes for covariance matrix
estimation. A lower bound on the spectral efficiency (SE) of any combining
scheme is derived, under imperfect covariance knowledge, and a closed-form
expression is computed for maximum-ratio combin- ing. We show that having
covariance information is not critical, but that it is relatively easy to
acquire it and to achieve SE close to the ideal case of having perfect
statistical information.


title:
Performance of arsenene and antimonene double-gate MOSFETs from first
  principles

abstract:
  In the race towards high-performance ultra-scaled devices, two-dimensional
materials offer an alternative paradigm thanks to their atomic thickness
suppressing short-channel effects. It is thus urgent to study the most
promising candidates in realistic configurations, and here we present detailed
multiscale simulations of field-effect transistors based on arsenene and
antimonene monolayers as channels. The accuracy of first-principles approaches
in describing electronic properties is combined with the efficiency of
tight-binding Hamiltonians based on maximally-localised Wannier functions to
compute the transport properties of the devices. These simulations provide for
the first time estimates on the upper limits for the electron and hole
mobilities in the Takagi's approximation, including spin-orbit and multi-valley
effects, and demonstrate that ultra-scaled devices in the sub-10 nm scale show
a performance that is compliant with industry requirements.


title:
Cramer-Rao Lower Bound for DoA Estimation with RF Lens-Embedded Antenna
  Array

abstract:
  In this paper, we consider the Cramer-Rao lower bound (CRLB) for estimation
of a lens-embedded antenna array with deterministic parameters. Unlike CRLB of
uniform linear array (ULA), it is noted that CRLB for direction of arrival
(DoA) of lens-embedded antenna array is dominated by not only angle but
characteristics of lens. Derivation is based on the approximation that
amplitude of received signal with lens is approximated to Gaussian function. We
confirmed that parameters needed to design a lens can be derived by standard
deviation of Gaussian, which represents characteristic of received signal, by
simulation of beam propagation method. Well-designed lens antenna shows better
performance than ULA in terms of estimating DoA. This is a useful derivation
because, result can be the guideline for designing parameters of lens to
satisfy certain purpose.


title:
Look into My Eyes: Fine-grained Detection of Face-screen Distance on
  Smartphones

abstract:
  The detection of face-screen distance on smartphone (i.e., the distance
between the user face and the smartphone screen) is of paramount importance for
many mobile applications, including dynamic adjustment of screen on-off, screen
resolution, screen luminance, font size, with the purposes of power saving,
protection of human eyesight, etc. Existing detection techniques for
face-screen distance depend on external or internal hardware, e.g., an
accessory plug-in sensor (e.g., infrared or ultrasonic sensors) to measure the
face-screen distance, a built-in proximity sensor that usually outputs a
coarse-grained, two-valued, proximity index (for the purpose of powering on/off
the screen), etc. In this paper, we present a fine-grained detection method,
called "Look Into My Eyes (LIME)", that utilizes the front camera and inertial
accelerometer of the smartphone to estimate the facescreen distance.
Specifically, LIME captures the photo of the user's face only when the
accelerometer detects certain motion patterns of mobile phones, and then
estimates the face-screen distance by looking at the distance between the
user's eyes. Besides, LIME is able to take care of the user experience when
multiple users are facing the phone screen. The experimental results show that
LIME can achieve a mean squared error smaller than 2.4 cm in all of
experimented scenarios, and it incurs a small cost on battery life when
integrated into an SMS application for enabling dynamic font size by detecting
the face-screen distance.


title: First-order strong-field QED processes in a tightly focused laser beam

abstract:
  In [Phys. Rev. Lett. \textbf{117}, 213201 (2016)] we have determined the
angular resolved and the total energy spectrum of a positron produced via
nonlinear Breit-Wheeler pair production by a high-energy photon
counterpropagating with respect to a tightly focused laser beam. Here, we first
generalize the results in [Phys. Rev. Lett. \textbf{117}, 213201 (2016)] by
including the possibility that the incoming photon is not exactly
counterpropagating with respect to the laser field. As main focus of the
present paper, we determine the photon angular resolved and total energy
spectrum for the related process of nonlinear Compton scattering by an electron
impinging into a tightly-focused laser beam. Analytical integral expressions
are obtained under the realistic assumption that the energy of the incoming
electron is the largest dynamical energy of the problem and that the electron
is initially almost counterpropagating with respect to the laser field. The
crossing symmetry relation between the two processes in a tightly focused laser
beam is also elucidated.


title: Coxeter element and particle masses

abstract:
  Let $\mathfrak{g}$ be a simple Lie algebra of rank $r$ over $\mathbb{C}$,
$\mathfrak{h} \subset \mathfrak{g}$ a Cartan subalgebra. We construct a family
of $r$ commuting Hermitian operators acting on $\mathfrak{h}$ whose eigenvalues
are equal to the coordinates of the eigenvectors of the Cartan matrix of
$\mathfrak{g}$.


title: Low thermal fluctuations in a system heated out of equilibrium

abstract:
  We study the mechanical fluctuations of a micrometer sized silicon cantilever
subjected to a strong heat flow, thus having a highly non-uniform local
temperature. In this non-equilibrium steady state, we show that fluctuations
are equivalent to the thermal noise of a cantilever at equilibrium around room
temperature, while its mean local temperature is several hundred of degrees
higher. Changing the mechanical dissipation by adding a coating to the
cantilever, we recover the expected rise of fluctuations with the mean
temperature. Our work demonstrates that inhomogeneous dissipation mechanisms
can decouple the amplitude of thermal fluctuations from the average
temperature. This property could be useful to understand out-of-equilibrium
fluctuating systems, or to engineer low noise instruments.


title:
An estimate of Alpha decay half-life from the poles of S-matrix of an
  exactly solvable potential

abstract:
  We develop a versatile and analytically solvable potential which fairly
reproduces the combined potential of an $\alpha+$nucleus system resulting from
both the attractive nuclear and repulsive electrostatic potentials. The
potential is expressed in terms of the radial position, mass and proton number
of the $\alpha$-particle and the daughter nucleus and certain parameters
governing the depth, height and steepness of the barrier. The potential
generated is typically a pocket near the origin and a barrier adjacent to it.
The Schr\"odinger equation with the above mentioned potential is then solved
for the wave function. This potential produces discrete positive energy
quasibound state known as resonance state. By matching the wave function and
its derivative with the regular Coulomb wave function $F_0$ and irregular
Coulomb wave function $G_0$, we obtain the S-matrix analytically. The resonance
is obtained from the pole in complex energy plane which gives the width of the
corresponding time of decay through the imaginary part of the energy pole
position. We make a comparative study of the measured half-lives of various
nuclei with the calculated half-lives. The calculated values of half-lives
closely match with the corresponding experimental results.


title:
Growth and instability of a phospholipid vesicle in a bath of fatty
  acids

abstract:
  Using a microfluidic trap, we study the behavior of individual phospholipid
vesicles in contact with fatty acids. We show that spontaneous fatty acids
insertion inside the bilayer is controlled by the vesicle size, osmotic
pressure difference across the membrane and fatty acids concentration in the
external bath. Depending on these parameters, vesicles can grow spherically or
become unstable and fragment into several daughter vesicles. We establish the
phase diagram for vesicle growth and we derive a simple thermodynamic model
that reproduces the time evolution of the vesicle volume. Finally, we show that
stable growth can be achieved on an artificial cell expressing a simple set of
bacterial cytoskeletal proteins, paving the way toward artificial cell
reproduction.


title: Number of Points on the Full Moduli Space of Curves over Finite Fields

abstract:
  The distribution of the number of points on abelian covers of
$\mathbb{P}1(\mathbb{F}_q)$ ranging over an irreducible moduli space has been
answered in recent work by the author. Bucur, et al. determined the
distribution over the whole moduli space for curves with Gal$(K(C)/K)$ a prime
cyclic. In this paper, we prove a result towards determining the distribution
over the whole moduli space of curves with Gal$(K(C)/K)$ any abelian group. We
successfully determine the distribution in the case Gal$(K(C)/K)$ is a power of
a prime cyclic.


title:
A uniqueness lemma with applications to regularization and
  incompressible fluid mechanics

abstract:
  In this paper, we extend our previous result from [16]. We prove that
transport equations with rough coefficients do possess a uniqueness property.
Our method relies strongly on duality and bears a strong resemblance with the
well-known DiPerna-Lions theory first developed in [8]. As an application, we
show a uniqueness result for the Euler and Navier-Stokes equations at the Leray
regularity scale. In turn, this theorem stands as a barrier against the
paradoxical weak solutions constructed in [17], [18], [19] and later
reformulated in [6].


title:
Towards Continuous Integration and Continuous Delivery in the Automotive
  Industry

abstract:
  Development cycles are getting shorter and Continuous Integration and
Delivery are being established in the automotive industry. We give an overview
of the peculiarities in an automotive deployment pipeline, introduce
technologies used and analyze Tesla's deliveries as a state-of-the-art
showcase.