title:
Electrical domain writing and nanoscale potential modulation on
  LaVO$_3$/SrTiO$_3$

abstract:
  The high-mobility 2DEGs formed at the interfaces between certain insulating
perovskite oxides have been known to be a novel playground of exotic physical
orders like, superconductivity and ferromagnetism and their inter-coupling.
There have been efforts to accomplish even more exotic properties at such
interfaces of oxide heterostructures through nano-structuring of the surface.
In this paper we report writing and erasing charge domains on such an oxide
heterostructure LaVO$_3$/SrTiO$_3$ using a conductive AFM cantilever. We have
patterned these domains in a periodic fashion in order to create artificial
lattices on the surface. Through kelvin probe microscopy, electrostatic force
microscopy and conductivity mapping of such artificial lattices we found that
the domains not only trap charge carriers but also develop a controllable
potential landscape on the surface which coincides with a modulation of local
electrical conductivity. The ability to pattern such nanostructures reversibly
offers unprecedented opportunities of realizing ultra-high storage density
devices in high mobility oxide heterostructures.


title:
A New Algorithm for Circulant Rational Covariance Extension and
  Applications to Finite-interval Smoothing

abstract:
  The partial stochastic realization of periodic processes from finite
covariance data has recently been solved by Lindquist and Picci based on convex
optimization of a generalized entropy functional. The meaning and the role of
this criterion have an unclear origin. In this paper we propose a solution
based on a nonlinear generalization of the classical Yule-Walker type equations
and on a new iterative algorithm which is shown to converge to the same
(unique) solution of the variational problem. This provides a conceptual link
to the variational principles and at the same time yields a robust algorithm
which can for example be successfully applied to finite-interval smoothing
problems providing a simpler procedure if compared with the classical
Riccati-based calculations.


title:
A perturbative approach to the confinement-deconfinement phase
  transition

abstract:
  We summarize recent progress in describing the confinement-deconfinement
transition from a novel perturbative approach.


title: Knapsack problem for automaton groups

abstract:
  The knapsack problem is a classic optimisation problem that has been recently
extended in the setting of groups. Its study reveals to be interesting since it
provides many different behaviours, depending on the considered class of
groups. In this paper we deal with groups generated by Mealy automata-a class
that is often used to study group-theoretical conjectures-and prove that the
knapsack problem is undecidable for this class. In a second time, we construct
a graph that, if finite, provides a solution to the knapsack problem. We deduce
that the knapsack problem is decidable for the so-called bounded automaton
groups, a class where the order and conjugacy problems are already known to be
decidable.


title: Constraining symmetron fields with atom interferometry

abstract:
  We apply the new constraints from atom-interferometry searches for screening
mechanisms to the symmetron model, finding that these experiments exclude a
previously unexplored region of parameter space. We discuss the possibility of
networks of domain walls forming in the vacuum chamber, and how this could be
used to discriminate between models of screening.


title: Complex-Path Prediction of Resonance-Assisted Tunneling in Mixed Systems

abstract:
  We present a semiclassical prediction of regular-to-chaotic tunneling in
systems with a mixed phase space, including the effect of a nonlinear resonance
chain. We identify complex paths for direct and resonance-assisted tunneling in
the phase space of an integrable approximation with one nonlinear resonance
chain. We evaluate the resonance-assisted contribution analytically and give a
prediction based on just a few properties of the classical phase space. For the
standard map excellent agreement with numerically determined tunneling rates is
observed. The results should similarly apply to ionization rates and quality
factors.


title:
Regularity results and Harnack inequalities for minimizers and solutions
  of nonlocal problems: a unified approach via fractional De Giorgi classes

abstract:
  We study energy functionals obtained by adding a possibly discontinuous
potential to an interaction term modeled upon a Gagliardo-type fractional
seminorm. We prove that minimizers of such non-differentiable functionals are
locally bounded, H\"older continuous, and that they satisfy a suitable Harnack
inequality. Hence, we provide an extension of celebrated results of M.
Giaquinta and E. Giusti to the nonlocal setting. To do this, we introduce a
particular class of fractional Sobolev functions, reminiscent of that
considered by E. De Giorgi in his seminal paper of 1957. The flexibility of
these classes allows us to also establish regularity of solutions to rather
general nonlinear integral equations.


title: On Size Biased Kumaraswamy Distribution

abstract:
  In this paper, we introduce and study the size-biased form of Kumaraswamy
distribution. The Kumaraswamy distribution which has drawn considerable
attention in hydrology and related areas was proposed by Kumarswamy. The new
distribution is derived under size-biased probability of sampling taking the
weights as the variate values. Various distributional and characterizing
properties of the model are studied. The methods of maximum likelihood and
matching quantiles estimation are employed to estimate the parameters of the
proposed model. Finally, we apply the proposed model to simulated and real data
sets.


title:
Photometric and Spectroscopic Study of the Supergiant with an Infrared
  Excess V1027 Cygni

abstract:
  We present the results of our $UBV$ and $JHKLM$-photometry for the
semiregular pulsating variable V1027~Cyg, a supergiant with an infrared excess,
over the period from 1991 to 2015. Our search for a periodicity in the $UBV$
brightness variations has led to several periods from $P=212^{d}$ to
$P=320^{d}$ in different time intervals. We have found the period $P=237^{d}$
based on our infrared photometry. The variability amplitude, the light-curve
shape, and the magnitude of V1027~Cyg at maximum light change noticeably from
cycle to cycle. An ambiguous correlation of the $B-V$ and $U-B$ colors with the
brightness has been revealed. The spectral energy distribution for V1027~Cyg
from our photometry in the range 0.36 ($U$)-5.0 ($M$) $\mu$m corresponds to
spectral types from G8I to K3I at different phases of the pulsation cycle.
Low-resolution spectra of V1027 Cyg in the range $\lambda$4400--9200 \AA\ were
taken during 16 nights over the period 1995--2015. At the 1995 and 2011
photometric minima the star's spectrum exhibited molecular TiO bands whose
intensity corresponded to spectral types M0--M1, while the photometric data
point to a considerably earlier spectral type. We hypothesize that the TiO
bands are formed in the upper layers of the extended stellar atmosphere. We
have measured the equivalent widths of the strongest absorption lines, in
particular, the infrared Ca~II triplet in the spectrum of V1027~Cyg. The
calcium triplet (Ca T) with $W_{\lambda}(\mathrm{Ca~T})=20.3\pm1.8$ \AA\ as a
luminosity indicator for supergiants places V1027 Cyg in the region of the
brightest G--K supergiants. V1027 Cyg has been identified with the infrared
source IRAS~20004+2955 and is currently believed to be a candidate for post-AGB
stars. The evolutionary status of the star and its difference from other
post-AGB objects are discussed.


title: Truncated transparent boundary conditions

abstract:
  We derive equations for evaluating differential operators in transparent
boundary conditions (TBCs) for a certain class of hyperbolic systems of
second-order equations. This local part of TBCs can be used as approximate
nonreflecting boundary conditions. We give examples of obtaining such truncated
TBCs for 3D elasticity and Biot poroelasticity


title: Self-stabilizing Byzantine Clock Synchronization with Optimal Precision

abstract:
  We revisit the approach to Byzantine fault-tolerant clock synchronization
based on approximate agreement introduced by Lynch and Welch. Our contribution
is threefold:
  (1) We provide a slightly refined variant of the algorithm yielding improved
bounds on the skew that can be achieved and the sustainable frequency offsets.
  (2) We show how to extend the technique to also synchronize clock rates. This
permits less frequent communication without significant loss of precision,
provided that clock rates change sufficiently slowly.
  (3) We present a coupling scheme that allows to make these algorithms
self-stabilizing while preserving their high precision. The scheme utilizes a
low-precision, but self-stabilizing algorithm for the purpose of recovery.


title: Optimal approximation of Skorohod integrals

abstract:
  In this manuscript, we determine the optimal approximation rate for Skorohod
integrals of sufficiently regular integrands. This generalizes the optimal
approximation results for It\^o integrals. However, without adaptedness and the
It\^o isometry, new proof techniques are required. The main tools are a
characterization via S-transform and a reformulation of the Wiener chaos
decomposition in terms of Wick-analytic functionals.


title: The self-normalized Donsker theorem revisited

abstract:
  We extend the Poincar\'{e}--Borel lemma to a weak approximation of a Brownian
motion via simple functionals of uniform distributions on n-spheres in the
Skorokhod space $D([0,1])$. This approach is used to simplify the proof of the
self-normalized Donsker theorem in Cs\"{o}rg\H{o} et al. (2003). Some notes on
spheres with respect to $\ell_p$-norms are given.


title: Rhodamine B as a probe for phase transition in liquid solutions

abstract:
  Local environment of fluorescent dyes could strongly affect emission dynamics
of the latter. In particular, both signal intensities and emission lifetimes
are highly sensitive to solvent temperatures. Here, temperature-dependent
behavior Rhodamine B fluorescence in water and ethanol solutions was
experimentally investigated. Phase transition point of liquid water to ice was
shown to have a dramatic impact on both in intensity (30-fold drop) and in
lifetime (from 2.68ns down to 0.13ns) of the dye luminescence along with the
spectral shift of spectral maxima from 590 to 625nm. At the same time, ethanol
solvent does not lead any similar behavior. The reported results and approaches
enable further investigations of dye-solvent interactions and studies of
physical properties of liquids at phase transition points.


title: The Abel Jacobi map for Mumford Curves via Integration

abstract:
  We construct the Abel-Jacobi map for Mumford curves over any complete
non-archimedean field, using multiplicative integrals and in the setting of
Berkovich analytic geometry. Along the way, we proof some results concerning
graphs and mesures related to tropical geometry.


title:
Surrogate models for oscillatory systems using sparse polynomial chaos
  expansions and stochastic time warping

abstract:
  Polynomial chaos expansions (PCE) have proven efficiency in a number of
fields for propagating parametric uncertainties through computational models of
complex systems, namely structural and fluid mechanics, chemical reactions and
electromagnetism, etc. For problems involving oscillatory, time-dependent
output quantities of interest, it is well-known that reasonable accuracy of
PCE-based approaches is difficult to reach in the long term. In this paper, we
propose a fully non-intrusive approach based on stochastic time warping to
address this issue: each realization (trajectory) of the model response is
first rescaled to its own time scale so as to put all sampled trajectories in
phase in a common virtual time line. Principal component analysis is introduced
to compress the information contained in these transformed trajectories and
sparse PCE representations using least angle regression are finally used to
approximate the components. The approach shows remarkably small prediction
error for particular trajectories as well as for second-order statistics of the
latter. It is illustrated on different benchmark problems well known in the
literature on time-dependent PCE problems, ranging from rigid body dynamics,
chemical reactions to forced oscillations of a non linear system.


title:
Two-time-scale stochastic partial differential equations driven by
  $\alpha$-stable noises: Averaging principles

abstract:
  This paper focuses on stochastic partial differential equations (SPDEs) under
two-time-scale formulation. Distinct from the work in the existing literature,
the systems are driven by $\alpha$-stable processes with $\alpha \in(1,2)$. In
addition, the SPDEs are either modulated by a continuous-time Markov chain with
a finite state space or have an addition fast jump component. The inclusion of
the Markov chain is for the needs of treating random environment, whereas the
addition of the fast jump process enables the consideration of discontinuity in
the sample paths of the fast processes. Assuming either a fast changing Markov
switching or an additional fast-varying jump process, this work aims to obtain
the averaging principles for such systems. There are several distinct
difficulties. First, the noise is not square integrable. Second, in our setup,
for the underlying SPDE, there is only a unique mild solution and as a result,
there is only mild It\^{o}'s formula that can be used. Moreover, another new
aspect is the addition of the fast regime switching and the addition of the
fast varying jump processes in the formulation, which enlarges the
applicability of the underlying systems. To overcome these difficulties, a
semigroup approach is taken. Under suitable conditions, it is proved that the
$p$th moment convergence takes place with $p\in(1,\alpha )$, which is stronger
than the usual weak convergence approaches.


title: Formula Slicing: Inductive Invariants from Preconditions

abstract:
  We propose a "formula slicing" method for finding inductive invariants. It is
based on the observation that many loops in the program affect only a small
part of the memory, and many invariants which were valid before a loop are
still valid after.
  Given a precondition of the loop, obtained from the preceding program
fragment, we weaken it until it becomes inductive. The weakening procedure is
guided by counterexamples-to-induction given by an SMT solver. Our algorithm
applies to programs with arbitrary loop structure, and it computes the
strongest invariant in an abstract domain of weakenings of preconditions. We
call this algorithm "formula slicing", as it effectively performs "slicing" on
formulas derived from symbolic execution.
  We evaluate our algorithm on the device driver benchmarks from the
International Competition on Software Verification (SV-COMP), and we show that
it is competitive with the state-of-the-art verification techniques.


title: Noether Symmetries in Gauss-Bonnet-teleparallel cosmology

abstract:
  A generalized teleparallel cosmological model, $f(T_\mathcal{G},T)$,
containing the torsion scalar $T$ and the teleparallel counterpart of the
Gauss-Bonnet topological invariant $T_{\mathcal{G}}$, is studied in the
framework of the Noether Symmetry Approach. As $f(\mathcal{G}, R)$ gravity,
where $\mathcal{G}$ is the Gauss-Bonnet topological invariant and $R$ is the
Ricci curvature scalar, exhausts all the curvature information that one can
construct from the Riemann tensor, in the same way, $f(T_\mathcal{G},T)$
contains all the possible information directly related to the torsion tensor.
In this paper, we discuss how the Noether Symmetry Approach allows to fix the
form of the function $f(T_\mathcal{G},T)$ and to derive exact cosmological
solutions.


title: Sonneberg plate photometry for Boyajian's Star in two passbands

abstract:
  The F3 main sequence star KIC 8462852 (Boyajian's Star) showed deep (up to
20%) day-long brightness dips of unknown cause during the 4 years of the Kepler
mission. A 0.164 mag (16%) dimming between 1890 and 1990 was claimed, based on
the analysis of photographic plates from the Harvard Observatory. We have
gathered an independent set of historic plates from Sonneberg Observatory,
Germany, covering the years 1934-1995. With 861 magnitudes in B, and 397
magnitudes in V, we find the star to be of constant brightness within 0.03 mag
per century (3%). Consistent outcomes are found using by-eye estimates of the
best 119 plates. Results are supported by data from Sternberg Observatory,
Moscow, which show the star as constant between 1895 and 1995. The previously
claimed century-long dimming is inconsistent with our results at the 5-sigma
level, however the recently reported modest dimming of 3% in the Kepler data is
not inconsistent with our data. We find no periodicities or shorter trends
within our limits of 5% per 5-year bin, but note a possible dimming event on 24
Oct 1978.


title: Permutations via linear translators

abstract:
  We show that many infinite classes of permutations over finite fields can be
constructed via translators with a large choice of parameters. We first charac-
terize some functions having linear translators, based on which several
families of permutations are then derived. Extending the results of [10], we
give in several cases the compositional inverse of these permutations. The
connection with complete permutations is also utilized to provide further
infinite classes of permutations. Moreover, we propose new tools to study
permutations of the form x is mapped to x+(x^(p^m) - x+ lambda)^s and a few
infinite classes of permutations of this form are proposed.


title: Souslin quasi-orders and bi-embeddability of uncountable structures

abstract:
  We provide analogues of the results from [FMR11, CMMR13] in the reference
list (which correspond to the case $\kappa = \omega$) for arbitrary
$\kappa$-Souslin quasi-orders on any Polish space, for $\kappa$ an infinite
cardinal smaller than the cardinality of $\mathbb{R}$. These generalizations
yield a variety of results concerning the complexity of the embeddability
relation between graphs or lattices of size $\kappa$, the isometric
embeddability relation between complete metric spaces of density character
$\kappa$, and the linear isometric embeddability relation between (real or
complex) Banach spaces of density $\kappa$.


title:
Jacob's ladders, interactions between $\zeta$-oscillating systems and
  $\zeta$-analogue of an elementary trigonometric identity

abstract:
  In our previous papers, we have introduced within the theory of the Riemann
zeta function the following notions: Jacob's ladders, oscillating systems,
$\zeta$-factorization, metamorphoses, \dots In this paper we obtain
$\zeta$-analogue of an elementary trigonometric identity and other interactions
between oscillating systems.


title: DynIMS: A Dynamic Memory Controller for In-memory Storage on HPC Systems

abstract:
  In order to boost the performance of data-intensive computing on HPC systems,
in-memory computing frameworks, such as Apache Spark and Flink, use local DRAM
for data storage. Optimizing the memory allocation to data storage is critical
to delivering performance to traditional HPC compute jobs and throughput to
data-intensive applications sharing the HPC resources. Current practices that
statically configure in-memory storage may leave inadequate space for compute
jobs or lose the opportunity to utilize more available space for data-intensive
applications. In this paper, we explore techniques to dynamically adjust
in-memory storage and make the right amount of space for compute jobs. We have
developed a dynamic memory controller, DynIMS, which infers memory demands of
compute tasks online and employs a feedback-based control model to adapt the
capacity of in-memory storage. We test DynIMS using mixed HPCC and Spark
workloads on a HPC cluster. Experimental results show that DynIMS can achieve
up to 5X performance improvement compared to systems with static memory
allocations.


title: Multiscale Model Approach for Magnetization Dynamics Simulations

abstract:
  Simulations of magnetization dynamics in a multiscale environment enable
rapid evaluation of the Landau-Lifshitz-Gilbert equation in a mesoscopic sample
with nanoscopic accuracy in areas where such accuracy is required. We have
developed a multiscale magnetization dynamics simulation approach that can be
applied to large systems with spin structures that vary locally on small length
scales. To implement this, the conventional micromagnetic simulation framework
has been expanded to include a multiscale solving routine. The software
selectively simulates different regions of a ferromagnetic sample according to
the spin structures located within in order to employ a suitable discretization
and use either a micromagnetic or an atomistic model. To demonstrate the
validity of the multiscale approach, we simulate the spin wave transmission
across the regions simulated with the two different models and different
discretizations. We find that the interface between the regions is fully
transparent for spin waves with frequency lower than a certain threshold set by
the coarse scale micromagnetic model with no noticeable attenuation due to the
interface between the models. As a comparison to exact analytical theory, we
show that in a system with Dzyaloshinskii-Moriya interaction leading to spin
spiral, the simulated multiscale result is in good quantitative agreement with
the analytical calculation.


title:
Comprehensive Evaluation of OpenCL-based Convolutional Neural Network
  Accelerators in Xilinx and Altera FPGAs

abstract:
  Deep learning has significantly advanced the state of the art in artificial
intelligence, gaining wide popularity from both industry and academia. Special
interest is around Convolutional Neural Networks (CNN), which take inspiration
from the hierarchical structure of the visual cortex, to form deep layers of
convolutional operations, along with fully connected classifiers. Hardware
implementations of these deep CNN architectures are challenged with memory
bottlenecks that require many convolution and fully-connected layers demanding
large amount of communication for parallel computation. Multi-core CPU based
solutions have demonstrated their inadequacy for this problem due to the memory
wall and low parallelism. Many-core GPU architectures show superior performance
but they consume high power and also have memory constraints due to
inconsistencies between cache and main memory. FPGA design solutions are also
actively being explored, which allow implementing the memory hierarchy using
embedded BlockRAM. This boosts the parallel use of shared memory elements
between multiple processing units, avoiding data replicability and
inconsistencies. This makes FPGAs potentially powerful solutions for real-time
classification of CNNs. Both Altera and Xilinx have adopted OpenCL co-design
framework from GPU for FPGA designs as a pseudo-automatic development solution.
In this paper, a comprehensive evaluation and comparison of Altera and Xilinx
OpenCL frameworks for a 5-layer deep CNN is presented. Hardware resources,
temporal performance and the OpenCL architecture for CNNs are discussed. Xilinx
demonstrates faster synthesis, better FPGA resource utilization and more
compact boards. Altera provides multi-platforms tools, mature design community
and better execution times.


title: Homotopies of Lie Crossed Module Morphisms

abstract:
  In this paper we will define notion homotopy of morphisms of crossed modules
of Lie algebras. Then we construct a groupoid structure of Lie crossed module
morphisms and their homotopies.


title:
Impact of the electronic band structure in high-harmonic generation
  spectra of solids

abstract:
  An accurate analytic model describing high-harmonic generation (HHG) in
solids is derived. Extensive first-principles simulations within a
time-dependent density-functional framework corroborate the conclusions of the
model. Our results reveal that: (i) the emitted HHG spectra are highly
anisotropic and laser-polarization dependent even for cubic crystals, (ii) the
harmonic emission is enhanced by the inhomogeneity of the electron-nuclei
potential, the yield is increased for heavier atoms, and (iii) the cutoff
photon energy is driver-wavelength independent. Moreover, we show that it is
possible to predict the laser polarization for optimal HHG in bulk crystals
solely from the knowledge of their electronic band structure. Our results pave
the way to better control and optimize HHG in solids by engineering their band
structure.


title: Yukawa's of light stringy states

abstract:
  Light massive string states can appear at D-brane intersections with small
angles. We compute tri-linear Yukawa couplings of such open-string states to
massless ones and to one another. Due to ambiguities in the normalisation of
the vertex operators, that involve twist fields, we proceed via factorization
of appropriate scattering amplitudes. Some peculiar features are observed that
may lead to interesting signatures at colliders in the future.


title:
Combining BRITE and ground-based photometry for the Beta Cephei star Nu
  Eridani: impact on photometric pulsation mode identification and detection of
  several g modes

abstract:
  We report a simultaneous ground and space-based photometric study of the Beta
Cephei star Nu Eridani. Half a year of observations have been obtained by four
of the five satellites constituting BRITE-Constellation, supplemented with
ground-based photoelectric photometry. We show that carefully combining the two
data sets virtually eliminates the aliasing problem that often hampers
time-series analyses. We detect 40 periodic signals intrinsic to the star in
the light curves. Despite a lower detection limit we do not recover all the
pressure and mixed modes previously reported in the literature, but we newly
detect six additional gravity modes. This behaviour is a consequence of
temporal changes in the pulsation amplitudes that we also detected for some of
the p modes. We point out that the dependence of theoretically predicted
pulsation amplitude on wavelength is steeper in visual passbands than those
observationally measured, to the extent that the three dominant pulsation modes
of Nu Eridani would be incorrectly identified using data in optical filters
only. We discuss possible reasons for this discrepancy.


title: Quantum communication games manifest preparation contextuality

abstract:
  Communication games are collaborative information processing tasks involving
a number of players with limited communication. Such games are useful tools for
studying physical theories. A physical theory exhibits preparation
contextuality whenever observed behaviour cannot be explained by a preparation
noncontextual model. Here we show that there is a fundamental connection
between the performance in communication games and the degree of preparation
(non)contextuality. For this purpose, we present a general framework that
allows us to construct communication games such that the game performance
corresponds to a measure of preparation (non)contextuality. We illustrate the
power of this framework by, 1) deriving many examples of tests of preparation
contextuality, 2) showing that quantum violations of Bell inequalities can be
derived from quantum violations of preparation noncontextuality, 3)
qualitatively and quantitatively explaining related previous results on
preparation contextuality in quantum communication games, and 4) solving the
open problem of revealing the preparation contextuality of the maximally mixed
quantum state in any dimension.


title: Mathieu Moonshine and Symmetry Surfing

abstract:
  Mathieu Moonshine, the observation that the Fourier coefficients of the
elliptic genus on K3 can be interpreted as dimensions of representations of the
Mathieu group M24, has been proven abstractly, but a conceptual understanding
in terms of a representation of the Mathieu group on the BPS states, is
missing. Some time ago, Taormina and Wendland showed that such an action can be
naturally defined on the lowest non-trivial BPS states, using the idea of
`symmetry surfing', i.e., by combining the symmetries of different K3 sigma
models. In this paper we find non-trivial evidence that this construction can
be generalized to all BPS states.


title:
Surviving scenario of stop decays for ATLAS $\ell+jets+E^{miss}_T$
  search

abstract:
  Recently ATLAS reported a $3.3\sigma$ excess in the stop search with
$\ell+jets+E_T^{miss}$ channel. We try to interpret the signal by a light stop
pair production in the MSSM. We find: (1) simple models where stop decays into
a higgsino or a bino are not favored. (2) an extension of them can explain the
data at $2\sigma$ level without conflicting with the other search channels. A
surviving possibility includes a light stop and a light higgsino, which is
expected in a natural SUSY scenario.


title: Lower Bounds for Protrusion Replacement by Counting Equivalence Classes

abstract:
  Garnero et al. [SIAM J. Discrete Math. 2015, 29(4):1864--1894] recently
introduced a framework based on dynamic programming to make applications of the
protrusion replacement technique constructive and to obtain explicit upper
bounds on the involved constants. They show that for several graph problems,
for every boundary size $t$ one can find an explicit set $\mathcal{R}_t$ of
representatives. Any subgraph $H$ with a boundary of size $t$ can be replaced
with a representative $H' \in \mathcal{R}_t$ such that the effect of this
replacement on the optimum can be deduced from $H$ and $H'$ alone. Their upper
bounds on the size of the graphs in $\mathcal{R}_t$ grow triple-exponentially
with $t$. In this paper we complement their results by lower bounds on the
sizes of representatives, in terms of the boundary size $t$. For example, we
show that each set of planar representatives $\mathcal{R}_t$ for Independent
Set or Dominating Set contains a graph with $\Omega(2^t / \sqrt{4t})$ vertices.
This lower bound even holds for sets that only represent the planar subgraphs
of bounded pathwidth. To obtain our results we provide a lower bound on the
number of equivalence classes of the canonical equivalence relation for
Independent Set on $t$-boundaried graphs. We also find an elegant
characterization of the number of equivalence classes in general graphs, in
terms of the number of monotone functions of a certain kind. Our results show
that the number of equivalence classes is at most $2^{2^t}$, improving on
earlier bounds of the form $(t+1)^{2^t}$.


title: Logarithmic vector fields and the Severi strata in the discriminant

abstract:
  The discriminant, $D$, in the base of a miniversal deformation of an
irreducible plane curve singularity, is partitioned according to the genus of
the (singular) fibre, or, equivalently, by the sum of the delta invariants of
the singular points of the fibre. The members of the partition are known as the
{\it Severi strata}. The smallest is the $\delta$-constant stratum,
$D(\delta)$, where the genus of the fibre is $0$. It is well known, by work of
Givental' and Varchenko, to be Lagrangian with respect to the symplectic form
$\Omega$ obtained by pulling back the intersection form on the cohomology of
the fibre via the period mapping. We show that the remaining Severi strata are
also co-isotropic with respect to $\Omega$, and moreover that the coefficients
of the expression of $\Omega^{\wedge k}$ with respect to a basis of
$\Omega^{2k}(\log D)$ are equations for $D(\delta-k+1)$, for
$k=1,\ldots,\delta$. These equations allow us to show that for $E_6$ and $E_8$,
$D(\delta)$ is Cohen-Macaulay (this was already shown by Givental' for
$A_{2k}$), and that, as far as we can calculate, for $A_{2k}$ all of the Severi
strata are Cohen-Macaulay. Our construction also produces a canonical rank 2
maximal Cohen Macaulay module on the discriminant.


title: Flexibility for tangent and transverse immersions in Engel manifolds

abstract:
  In this article we study immersions of the circle that are tangent to an
Engel structure $\mathcal{D}$. We show that a full $h$-principle does exist as
soon as one excludes the closed orbits of $\mathcal{W}$, the kernel of
$\mathcal{D}$. This is sharp: we elaborate on work of Bryant and Hsu to show
that curves tangent to $\mathcal{W}$ often conform additional isolated
components that cannot be detected at a formal level. We then show that this is
an exceptional phenomenon: if $\mathcal{D}$ is generic, curves tangent to
$\mathcal{W}$ are not isolated anymore.
  We then go on to show that a full $h$-principle holds for immersions
transverse to the Engel structure.


title: Probing the Intrinsic Optical Quality of CVD Grown MoS2

abstract:
  The optical emission efficiency of two dimensional layered transition metal
dichalcogenides (TMDs) is one of the most important parameter that affects
their optoelectronic performance. Optimization of growth parameters of chemical
vapor deposition (CVD) to achieve optoelectronics-grade quality TMDs is
therefore highly desirable. Here, we present a systematic photoluminescence
(PL) spectroscopic approach to assess the intrinsic optical and crystalline
quality of CVD grown MoS2. We suggest that the intensity ratio between PL
measured in air and vacuum could be used as an effective way to monitor the
intrinsic optical quality of CVD MoS2. Low temperature PL measurements are also
used to evaluate the structural defects in MoS2 by defect-associated bound
exciton emission, which is well correlated with the field effect carrier
mobilities of MoS2 grown at different temperatures. This work therefore
provides a sensitive, noninvasive method to characterize the optical properties
of TMDs, allow tuning of growth parameters for the development of
optoelectronic devices.


title: Intensity contrast of the average supergranule

abstract:
  While the velocity fluctuations of supergranulation dominate the spectrum of
solar convection at the solar surface, very little is known about the
fluctuations in other physical quantities like temperature or density at
supergranulation scale. Using SDO/HMI observations, we characterize the
intensity contrast of solar supergranulation at the solar surface. We identify
the positions of ${\sim}10^4$ outflow and inflow regions at supergranulation
scales, from which we construct average flow maps and co-aligned intensity and
magnetic field maps. In the average outflow center, the maximum intensity
contrast is $(7.8\pm0.6)\times10^{-4}$ (there is no corresponding feature in
the line-of-sight magnetic field). This corresponds to a temperature
perturbation of about $1.1\pm0.1$ K, in agreement with previous studies. We
discover an east-west anisotropy, with a slightly deeper intensity minimum east
of the outflow center. The evolution is asymmetric in time: the intensity
excess is larger 8 hours before the reference time (the time of maximum
outflow), while it has almost disappeared 8 hours after the reference time. In
the average inflow region, the intensity contrast mostly follows the magnetic
field distribution, except for an east-west anisotropic component that
dominates 8 hours before the reference time. We suggest that the east-west
anisotropy in the intensity is related to the wave-like properties of
supergranulation.


title:
Sub-system fidelity for ground states in one dimensional interacting
  systems

abstract:
  We propose to utilize the sub-system fidelity (SSF), defined by comparing a
pair of reduced density matrices derived from the degenerate ground states, to
identify and/or characterize symmetry protected topological (SPT) states in
one-dimensional interacting many-body systems. The SSF tells whether two states
are locally indistinguishable (LI) by measurements within a given sub-system.
Starting from two polar states (states that could be distinguished on either
edge), the other combinations of these states can be mapped onto a Bloch
sphere. We prove that a pair of orthogonal states on the equator of the Bloch
sphere are LI, independently of whether they are SPT states or cat states
(symmetry-preserving states by linear combinations of states that break
discrete symmetries). Armed with this theorem, we provide a scheme to construct
zero-energy exitations that swap the LI states. We show that the zero mode can
be located anywhere for cat states, but is localized near the edge for SPT
states. We also show that the SPT states are LI in a finite fraction of the
bulk (excluding the two edges), whereas the symmetry-breaking states are
distinguishable. This can be used to pinpoint the transition from SPT states to
the symmetry-breaking states.


title: One-loop diagrams in the Random Euclidean Matching Problem

abstract:
  The matching problem is a notorious combinatorial optimization problem that
has attracted for many years the attention of the statistical physics
community. Here we analyze the Euclidean version of the problem, i.e. the
optimal matching problem between points randomly distributed on a
$d$-dimensional Euclidean space, where the cost to minimize depends on the
points' pairwise distances. Using Mayer's cluster expansion we write a formal
expression for the replicated action that is suitable for a saddle point
computation. We give the diagrammatic rules for each term of the expansion, and
we analyze in detail the one-loop diagrams. A characteristic feature of the
theory, when diagrams are perturbatively computed around the mean field part of
the action, is the vanishing of the mass at zero momentum. In the non-Euclidean
case of uncorrelated costs instead, we predict and numerically verify an
anomalous scaling for the sub-sub-leading correction to the asymptotic average
cost.


title: The Stern-Gerlach Experiment Revisited

abstract:
  The Stern-Gerlach-Experiment (SGE) of 1922 is a seminal benchmark experiment
of quantum physics providing evidence for several fundamental properties of
quantum systems. Based on today's knowledge we illustrate the different
benchmark results of the SGE for the development of modern quantum physics and
chemistry.
  The SGE provided the first direct experimental evidence for angular momentum
quantization in the quantum world and thus also for the existence of
directional quantization of all angular momenta in the process of measurement.
It measured for the first time a ground state property of an atom, it produced
for the first time a `spin-polarized' atomic beam, it almost revealed the
electron spin. The SGE was the first fully successful molecular beam experiment
with high momentum-resolution by beam measurements in vacuum. This technique
provided a new kinematic microscope with which inner atomic or nuclear
properties could be investigated.
  The original SGE is described together with early attempts by Einstein,
Ehrenfest, Heisenberg, and others to understand directional quantization in the
SGE. Heisenberg's and Einstein's proposals of an improved multi-stage SGE are
presented. The first realization of these proposals by Stern, Phipps, Frisch
and Segr\`e is described. The set-up suggested by Einstein can be considered an
anticipation of a Rabi-apparatus. Recent theoretical work is mentioned in which
the directional quantization process and possible interference effects of the
two different spin states are investigated.
  In full agreement with the results of the new quantum theory directional
quantization appears as a general and universal feature of quantum
measurements. One experimental example for such directional quantization in
scattering processes is shown. Last not least, the early history of the
`almost' discovery of the electron spin in the SGE is revisited.


title: Magneto photoluminescence measurements of tungsten disulphide monolayers

abstract:
  Layered transition-metal dichalcogenides have attracted great interest in the
last few years. Thinned down to the monolayer limit they change from an
indirect band structure to a direct band gap in the visible region. Due to the
monolayer thickness the inversion symmetry of the crystal is broken and spin
and valley are coupled to each other. The degeneracy between the two equivalent
valleys, K and K', respectively, can be lifted by applying an external magnetic
field. Here, we present photoluminescence measurements of CVD-grown tungsten
disulphide (WS${_2}$) monolayers at temperatures of 2 K. By applying magnetic
fields up to 7 T in Faraday geometry, a splitting of the photoluminescence
peaks can be observed. The magnetic field dependence of the A-exciton, the
trion and three bound exciton states is discussed and the corresponding
g-factors are determined.


title: An Algebraic Solution for the Kermack-McKendrick Model

abstract:
  We present an algebraic solution for the Susceptible-Infective-Removed (SIR)
model originally presented by Kermack-McKendrick in 1927. Starting from the
differential equation for the removed subjects presented by them in the
original paper, we re-write it in a slightly different form in order to derive
formally the solution, unless one integration. Then, using algebraic techniques
and some well justified numerical assumptions we obtain an analytic solution
for the integral. Finally, we compare the numerical solution of the
differential equations of the SIR model with the analytically solution here
proposed, showing an excellent agreement.


title:
A New Queue Discipline for Reducing Bufferbloat Effects in HetNet
  Concurrent Multipath Transfer

abstract:
  Heterogeneous wireless networks have evolved to reach application
requirements for low latency and high throughput on Internet access. Recent
studies have improved network performance employing the Multipath TCP, which
aggregates flows from heterogeneous wireless interfaces in a single connection.
Although existing proposals are powerful, coupled congestion control algorithms
are currently limited because of the high variation in path delays, bandwidth
and loss rate, typical from heterogeneous wireless networks, even more over
concurrent multipath transmissions. These transmissions experience bufferbloat,
i.e., high delays caused by long queues. Hence, to cope with the current
limitations, this work presents CoDel-LIFO, a new active queue management (AQM)
discipline to reduce the dropped packet ratio in the Multipath TCP congestion
control mechanism. Differently from other approaches, CoDel-LIFO gives priority
to the most recent packets, being then promising. This paper provides a
detailed simulation analysis over congestion control algorithms by comparing
CoDel-LIFO to CoDel and DropTail disciplines. Results indicate that CoDel-LIFO
reduces queue drops, diminishing the impact on congestion control; improving
substantially the goodput; and keeping RTT low.


title: Semantic Parsing with Semi-Supervised Sequential Autoencoders

abstract:
  We present a novel semi-supervised approach for sequence transduction and
apply it to semantic parsing. The unsupervised component is based on a
generative model in which latent sentences generate the unpaired logical forms.
We apply this method to a number of semantic parsing tasks focusing on domains
with limited access to labelled training data and extend those datasets with
synthetically generated logical forms.


title: Large scale spatio-temporal behaviour in surface growth

abstract:
  This paper presents new findings concerning the dynamics of the slow height
variations in surfaces produced by the two-dimensional isotropic
Kuramoto-Sivashinsky equation with an additional nonlinear term. In addition to
the disordered patterns of specific size evident at small scales, slow height
variations of scale-free character become increasingly evident when the system
size is increased. The surface spectrum at small wave numbers has a power-law
shape with a lower cut-off due to the finite system size. The temporal
properties of these long-range height variations are investigated by analysing
the time series of surface roughness fluctuations. The resulting power-spectral
densities can be expressed as a sum of white noise and a generalized Lorentzian
whose cut-off frequency varies with system size. The dependence of this lower
cut-off frequency on the smallest wave number connects spatial and temporal
properties and gives new insight into the surface evolution on large scales.


title:
The s-Process Nucleosynthesis in Extremely Metal-Poor Stars as the
  Generating Mechanism of Carbon Enhanced Metal-Poor Stars

abstract:
  The origin of carbon-enhanced metal-poor (CEMP) stars plays a key role in
characterising the formation and evolution of the first stars and the Galaxy
since the extremely-poor (EMP) stars with [Fe/H] \leq -2.5 share the common
features of carbon enhancement in their surface chemical compositions. The
origin of these stars is not yet established due to the controversy of the
origin of CEMP stars without the enhancement of s-process element abundances,
i.e., so called CEMP-no stars. In this paper, we elaborate the s-process
nucleosynthesis in the EMP AGB stars and explore the origin of CEMP stars. We
find that the efficiency of the s-process is controlled by O rather than Fe at
[Fe/H] \lesssim -2. We demonstrate that the relative abundances of Sr, Ba, Pb
to C are explained in terms of the wind accretion from AGB stars in binary
systems.


title:
Holographic paramagnetism-ferromagnetism phase transition with the
  nonlinear electrodynamics

abstract:
  In the probe limit, we investigate the nonlinear electrodynamical effects of
the both exponential form and the logarithmic form on the holographic
paramagnetism-ferromagnetism phase transition in the background of a
Schwarzschild-AdS black hole spacetime. Moreover, by comparing the exponential
form of nonlinear electrodynamics with the logarithmic form of nonlinear
electrodynamics and the Born-Infeld nonlinear electrodynamics which has been
presented in Ref.~\cite{Wu:2016uyj}, we find that the higher nonlinear
electrodynamics correction makes the critical temperature smaller and the
magnetic moment harder form in the case without external field. Furthermore,
the increase of nonlinear parameter b will result in extending the period of
the external magnetic field. Especially, the effect of the exponential form of
nonlinear electrodynamics on the periodicity of hysteresis loop is more
noticeable.


title:
Criterion for the integrality of hypergeometric series with parameters
  from quadratic fields

abstract:
  For the hypergeometric series with parameters from the rational fields, there
is an effective criterion due to Christol to decide whether the hypergeometric
series is N-integral or not. Christol criterion is a basic and vital tool in
the recent striking work of Delaygue, Rivoal and Roques on the N-integrality of
the hypergeometric mirror maps with rational parameters. In this paper, we
develop a systematic theory on the N-integrality of the hypergeometric series
with parameters from quadratic fields. We first present a detailed $p$-adic
analysis to set up a criterion of the $p$-adic integrality of the
hypergeometric series with parameters from rational fields. Consequently, we
present two equivalent statements for the hypergeometric series with parameters
from algebraic number fields to be N-integral. Finally, by using these results,
introducing a new function that extends the Christol's function and developing
a further $p$-adic analysis, we establish a criterion for the N-integrality of
the hypergeometric series with parameters from the quadratic fields. In the
process, there are two important ingredients. One is the uniform distribution
result of roots of a quadratic congruence which is due to Duke, Friedlander and
Iwaniec together with Toth. Another one is an upper bound on the number of
solutions of polynomial congruences given by Stewart in 1991.


title: Phases of $\mathcal{N}=4$ SYM, S-duality and Nilpotent Cones

abstract:
  In this note, I describe the space of vacua $\mathcal{V}$ of four dimensional
$\mathcal{N}=4$ SYM on $\mathbb{R}^4$ with gauge group a compact simple Lie
Group $G$ as a stratified space. On each stratum, the low energy effective
field theory is different. This language allows one to make precise the idea of
moving in the space of vacua $\mathcal{V}$. A particular subset of the strata
of $\mathcal{N}=4$ SYM can be efficiently described using the theory of sheets
in a Lie algebra. For these strata, I study the conjectural action of
S-duality. I also indicate some benefits of using such a language for the study
of the available space of vacua $\overline{\mathcal{V}}$ on the boundary of GL
twisted $\mathcal{N}=4$ SYM on a half-space $\mathbb{R}^3 \times \mathbb{R}^+$.
As an application of boundary symmetry breaking, I indicate how a) the Local
Nilpotent Cone arises as part of the available symmetry breaking choices on the
boundary of the four dimensional theory and b) the Global Nilpotent Cone arises
in the theory reduced down to two dimensions on a Riemann Surface $C$. These
geometries play a critical role in the Local and Global Geometric Langlands
Program(s).


title: The Hamilton-Waterloo problem with C8-factors and Cm-factors

abstract:
  In this paper, we almost completely solve the Hamilton-Waterloo problem with
C8- factors and Cm-factors where the number of vertices is a multiple of 8m.


title:
Modified viscosity in accretion disks. Application to Galactic black
  hole binaries, intermediate mass black holes and AGN

abstract:
  Black holes (BHs) surrounded by accretion disks are present in the Universe
at different scales of masses, from microquasars up to the active galactic
nuclei (AGNs). The current picture remains ad hoc due to the complexity of the
magnetic field action. In addition, accretion disks at high Eddington rates can
be radiation-pressure dominated and, according to some of the heating
prescriptions, thermally unstable. The observational verification of their
resulting variability patterns may shed light on both the role of radiation
pressure and magnetic fields. We compute the structure and time evolution of an
accretion disk, using the code GLADIS (which models the global accretion disk
instability). We supplement this model with a modified viscosity prescription,
which can to some extent describe the magnetisation of the disk. We study the
results for a large grid of models, to cover the whole parameter space, and we
derive conclusions separately for different scales of black hole masses, which
are characteristic for various types of cosmic sources. We show the
dependencies between the flare or outburst duration, its amplitude, and period,
on the accretion rate and viscosity scaling. We show that if the heating rate
in the accretion disk grows more rapidly with the total pressure and
temperature, the instability results in longer and sharper flares. In general,
we confirm that the disks around the supermassive black holes are more
radiation-pressure dominated and present relatively brighter bursts. Our method
can also be used as an independent tool for the black hole mass determination,
which we confront now for the intermediate black hole in the source HLX-1.


title:
Simulating phase transitions by means of quasi static state changes: the
  capabilities of the time dependent Van der Waals equation of state

abstract:
  The Van der Waals equation (VdW-EoS) is a prototype equation of state for
realistic systems, because it contains the excluded volume and the particle
interactions. Additionally, the simulated annealing (and the similar simulated
compressing) approach applies the time dependence on to one of the variables of
state to simulate quasi static state changes. The combination of both enables
the simulation of time dependent processes like phase transitions of
subcritical, critical and supercritical substances on every arbitrary condition
including a passage over points of singularity of the corresponding
susceptibility coefficients. This is achieved by a new simulation approach
called simulated expansion. This approach makes the simulation comparable to
natural processes which exhibit gradual changes in volume, rather than changes
in temperature or pressure, as exercised in simulated annealing or compressing.
The demonstrated method here serves as a blue print for more general classes of
simulation approaches.


title:
Performance of algorithms that reconstruct missing transverse momentum
  in $\sqrt{s}=$ 8 TeV proton-proton collisions in the ATLAS detector

abstract:
  The reconstruction and calibration algorithms used to calculate missing
transverse momentum ($E_{\rm T}^{\rm miss}$) with the ATLAS detector exploit
energy deposits in the calorimeter and tracks reconstructed in the inner
detector as well as the muon spectrometer. Various strategies are used to
suppress effects arising from additional proton-proton interactions, called
pileup, concurrent with the hard-scatter processes. Tracking information is
used to distinguish contributions from the pileup interactions using their
vertex separation along the beam axis. The performance of the $E_{\rm T}^{\rm
miss}$ reconstruction algorithms, especially with respect to the amount of
pileup, is evaluated using data collected in proton-proton collisions at a
centre-of-mass energy of 8 TeV during 2012, and results are shown for a data
sample corresponding to an integrated luminosity of 20.3 fb$^{-1}$. The results
of simulation modelling of $E_{\rm T}^{\rm miss}$ in events containing a $Z$
boson decaying to two charged leptons (electrons or muons) or a $W$ boson
decaying to a charged lepton and a neutrino is compared to data. The acceptance
for different event topologies, with and without high transverse momentum
neutrinos, is shown for a range of threshold criteria for $E_{\rm T}^{\rm
miss}$, and estimates of the systematic uncertainties in the $E_{\rm T}^{\rm
miss}$ measurements are presented.


title:
High-resolution IR absorption spectroscopy of polycyclic aromatic
  hydrocarbons in the 3 {\mu}m region: Role of periphery

abstract:
  In this work we report on high-resolution IR absorption studies that provide
a detailed view on how the peripheral structure of irregular polycyclic
aromatic hydrocarbons (PAHs) affects the shape and position of their 3 {\mu}m
absorption band. To this purpose we present mass-selected, high-resolution
absorption spectra of cold and isolated phenanthrene, pyrene, benz[a]antracene,
chrysene, triphenylene, and perylene molecules in the 2950-3150 cm-1 range. The
experimental spectra are compared with standard harmonic calculations, and
anharmonic calculations using a modified version of the SPECTRO program that
incorporates a Fermi resonance treatment utilizing intensity redistribution. We
show that the 3 {\mu}m region is dominated by the effects of anharmonicity,
resulting in many more bands than would have been expected in a purely harmonic
approximation. Importantly, we find that anharmonic spectra as calculated by
SPECTRO are in good agreement with the experimental spectra. Together with
previously reported high-resolution spectra of linear acenes, the present
spectra provide us with an extensive dataset of spectra of PAHs with a varying
number of aromatic rings, with geometries that range from open to
highly-condensed structures, and featuring CH groups in all possible edge
configurations. We discuss the astrophysical implications of the comparison of
these spectra on the interpretation of the appearance of the aromatic infrared
3 {\mu}m band, and on features such as the two-component emission character of
this band and the 3 {\mu}m emission plateau.


title:
When the clock strikes: Modeling the relation between circadian rhythms
  and cardiac arrhythmias

abstract:
  It has recently been observed that the occurrence of sudden cardiac death has
a close statistical relationship with the time of day, viz., ventricular
fibrillation is most likely to occur between 12 am-6 am, with 6 pm-12 am being
the next most likely period. Consequently there has been significant interest
in understanding how cardiac activity is influenced by the circadian clock,
i.e., temporal oscillations in physiological activity with a period close to 24
hours and synchronized with the day-night cycle. Although studies have
identified the genetic basis of circadian rhythms at the intracellular level,
the mechanisms by which they influence cardiac pathologies are not yet fully
understood. Evidence has suggested that diurnal variations in the conductance
properties of ion channel proteins that govern the excitation dynamics of
cardiac cells may provide the crucial link. In this paper, we investigate the
relationship between the circadian rhythm as manifested in modulations of ion
channel properties and the susceptibility to cardiac arrhythmias by using a
mathematical model that describes electrical activity in ventricular tissue. We
show that changes in the channel conductance that lead to extreme values for
the duration of action potentials in cardiac cells can result either in
abnormally high-frequency reentrant activity or spontaneous conduction block of
excitation waves. Both phenomena increase the likelihood of wavebreaks that are
known to initiate potentially life-threatening arrhythmias. Thus, disruptive
cardiac excitation dynamics are most likely to occur in time-intervals of the
day-night cycle during which the channel properties are closest to these
extreme values, providing an intriguing relation between circadian rhythms and
cardiac pathologies.


title: On the first hitting times of one dimensional elliptic diffusions

abstract:
  In this article, we obtain properties of the law associated to the first
hitting time of a threshold by a one-dimensional uniformly elliptic diffusion
process and to the associated process stopped at the threshold. Our methodology
relies on the parametrix method that we apply to the associated Markov
semigroup. It allows to obtain explicit expressions for the corresponding
transition densities and to study its regularity properties up to the boundary
under mild assumptions on the coefficients. As a by product, we also provide
Gaussian upper estimates for these laws and derive a probabilistic
representation that may be useful for the construction of an unbiased Monte
Carlo path simulation method, among other applications.


title: Proof of Gaussian moment product conjecture

abstract:
  For an $n$-dimensional real-valued centered Gaussian random vector
$(X_1,\ldots,X_n)$ with any covariance matrix, the following moment product
conjecture is proved in this paper \[ \mathbb{E}\prod_{j=1}^nX_j^{2m_j}\geq
\prod_{j=1}^n\mathbb{E}X_j^{2m_j}, \] where $m_j\geq1,1\leq j\leq n,$ are any
positive integers. Among other important applications, a special case of this
conjecture (with $m_j=m,1\leq j\leq n$) would give an affirmative answer to
another open problem: real linear polarization constant. The proof is based on
a very elegant and elementary approach in which only one component $X_j$ of the
random vector is chosen with varying variance.


title:
k-rAC - a Fine-Grained k-Resilient Access Control Scheme for Distributed
  Hash Tables

abstract:
  Distributed Hash Tables (DHT) are a common architecture for decentralized
applications and, therefore, would be suited for privacy-aware applications.
However, currently existing DHTs allow every peer to access any index. To build
privacy-aware applications, we need to control this access. In this paper, we
present k-rAC, a privacy-aware fine-grained AC for DHTs. For authentication, we
present three different mechanisms based on public-key cryptography,
zero-knowledge-proofs, and cryptographic hashes. For authorization, we use
distributed AC lists. The security of our approach is based on k-resilience. We
show that our approach introduces an acceptable overhead and discuss its
suitability for different scenarios.


title: Variational symmetries as the existence of ignorable coordinates

abstract:
  It is shown that given a Lagrangian for a system with a finite number of
degrees of freedom, the existence of a variational symmetry is equivalent to
the existence of coordinates in the extended configuration space such that one
of the coordinates is ignorable.


title: Consistency of detrended fluctuation analysis

abstract:
  The scaling function $F(s)$ in detrended fluctuation analysis (DFA) scales as
$F(s)\sim s^{H}$ for stochastic processes with Hurst exponents $H$. We prove
this scaling law for both stationary stochastic processes with $0<H<1$, and
non-stationary stochastic processes with $1<H<2$. For $H<0.5$ we observe that
using the asymptotic (power-law) auto-correlation function (ACF) yield
$F(s)\sim s^{1/2}$. We also show that the fluctuation function in DFA is equal
in expectation to: i) A weighted sum of the ACF ii) A weighted sum of the
second order structure function. These results enable us to compute the exact
finite-size bias for signals that are scaling, as well as studying DFA for
signals that do not have power-law statistics. We illustrate this with
examples, where we find that a previous suggested modified DFA will increase
the bias for signals with Hurst exponents $H>1$. As a final application of the
new theory, we present an estimator $\hat F(s)$ that can handle missing data in
regularly sampled time series without the need for interpolation schemes. Under
mild regularity conditions, $\hat F(s)$ is equal in expectation to the
fluctuation function $F(s)$ in the gap-free case.


title:
Liouville theorems, Volume growth, and volume comparison for Ricci
  shrinkers

abstract:
  In this paper, we study volume growth, Liouville theorem and the local
gradient estimate for $f$-harmonic functions, and volume comparison property of
unit balls in complete noncompact gradient Ricci shrinkers. We also study
integral properties of f-harmonic functions and harmonic functions on such
manifolds.


title:
Towards performance portability through locality-awareness for
  applications using one-sided communication primitives

abstract:
  MPI is the most widely used data transfer and communication model in High
Performance Computing. The latest version of the standard, MPI-3, allows
skilled programmers to exploit all hardware capabilities of the latest and
future supercomputing systems. The revised asynchronous remote-memory-access
model in combination with the shared-memory window extension, in particular,
allow writing code that hides communication latencies and optimizes
communication paths according to the locality of data origin and destination.
The latter is particularly important for today's multi- and many-core systems.
However, writing such efficient code is highly complex and error-prone. In this
paper we evaluate a recent remote-memory-access model, namely DART-MPI. This
model claims to hide the aforementioned complexities from the programmer, but
deliver locality-aware remote-memory-access semantics which outperforms MPI-3
one-sided communication primitives on multi-core systems. Conceptually, the
DART-MPI interface is simple; at the same time it takes care of the
complexities of the underlying MPI-3 and system topology. This makes DART-MPI
an interesting candidate for porting legacy applications. We evaluate these
claims using a realistic scientific application, specifically a
finite-difference stencil code which solves the heat diffusion equation, on a
large-scale Cray XC40 installation.


title:
Gaussian distribution of short sums of trace functions over finite
  fields

abstract:
  We show that under certain general conditions, short sums of $\ell$-adic
trace functions over finite fields follow a normal distribution asymptotically
when the origin varies, generalizing results of Erd\H{o}s-Davenport,
Mak-Zaharescu and Lamzouri. In particular, this applies to exponential sums
arising from Fourier transforms such as Kloosterman sums or Birch sums, as we
can deduce from the works of Katz. By approximating the moments of traces of
random matrices in monodromy groups, a quantitative version can be given as in
Lamzouri's article, exhibiting a different phenomenon than the averaging from
the central limit theorem.


title: On the weak approximation of a skew diffusion by an Euler-type scheme

abstract:
  We study the weak approximation error of a skew diffusion with bounded
measurable drift and H\"older diffusion coefficient by an Euler-type scheme,
which consists of iteratively simulating skew Brownian motions with constant
drift. We first establish two sided Gaussian bounds for the density of this
approximation scheme. Then, a bound for the difference between the densities of
the skew diffusion and its Euler approximation is obtained. Notably, the weak
approximation error is shown to be of order $h^{\eta/2}$, where $h$ is the time
step of the scheme, $\eta$ being the H\"older exponent of the diffusion
coefficient.


title:
On the integral of products of higher-order Bernoulli and Euler
  polynomials

abstract:
  In this paper, we derive a formula on the integral of products of the
higher-order Euler polynomials. By the same way, similar relations are obtained
for $l$ higher-order Bernoulli polynomials and $r$ higher-order Euler
polynomials. Moreover, we establish the connection between the results and the
generalized Dedekind sums and Hardy--Berndt sums. Finally, the Laplace
transform of Euler polynomials is given.


title:
The Kurdyka-{\L}ojasiewicz-Simon inequality and stabilisation in
  nonsmooth infinite-dimensional gradient systems

abstract:
  We state and prove a stabilisation result for solutions of abstract gradient
systems associated with nonsmooth energy functions on infinite dimensional
Hilbert spaces. One feature is that in this general setting the assumption on
the range of the solution can be considerably relaxed, which considerably
simplifies the applicability of the stabilisation result even in the case of
smooth energies.


title:
Front propagation and quasi-stationary distributions for one-dimensional
  L\'evy processes

abstract:
  We jointly investigate the existence of quasi-stationary distributions for
one dimensional L\'evy processes and the existence of traveling waves for the
Fisher-Kolmogorov-Petrovskii-Piskunov (F-KPP) equation associated with the same
motion. Using probabilistic ideas developed by S. Harris, we show that the
existence of a traveling wave for the F-KPP equation associated with a centered
L\'evy processes that branches at rate $r$ and travels at velocity $c$ is
equivalent to the existence of a quasi-stationary distribution for a L\'evy
process with the same movement but drifted by $-c$ and killed at zero, with
mean absorption time $1/r$. This also extends the known existence conditions in
both contexts. As it is discussed in a companion article, this is not just a
coincidence but the consequence of a relation between these two phenomena.


title: Linking Behavior in the PER Coauthorship Network

abstract:
  There is considerable long-term interest in understanding the dynamics of
collaboration networks, and how these networks form and evolve over time. Most
of the work done on the dynamics of social networks focuses on well-established
communities. Work examining emerging social networks is rarer, simply because
data is difficult to obtain in real time. In this paper, we use thirty years of
data from an emerging scientific community to look at that crucial early stage
in the development of a social network. We show that when the field was very
young, islands of individual researchers labored in relative isolation, and the
coauthorship network was disconnected. Thirty years later, rather than a
cluster of individuals, we find a true collaborative community, bound together
by a robust collaboration network. However, this change did not take place
gradually\textemdash the network remained a loose assortment of isolated
individuals until the mid-2000s, when those smaller parts suddenly knit
themselves together into a single whole. In the rest of this paper, we consider
the role of three factors in these observed structural changes: growth, changes
in social norms, and the introduction of institutions such as field-specific
conferences and journals. We have data from the very earliest years of the
field, a period which includes the introduction of two different institutions:
the first field-specific conference, and the first field-specific journals. We
also identify two relevant behavioral shifts: a discrete increase in
coauthorship coincident with the first conference, and a shift among
established authors away from collaborating with outsiders, towards
collaborating with each other. The interaction of these factors gives us
insight into the formation of collaboration networks more broadly.


title:
Measuring Economic Resilience to Natural Disasters with Big Economic
  Transaction Data

abstract:
  This research explores the potential to analyze bank card payments and ATM
cash withdrawals in order to map and quantify how people are impacted by and
recover from natural disasters. Our approach defines a disaster-affected
community's economic recovery time as the time needed to return to baseline
activity levels in terms of number of bank card payments and ATM cash
withdrawals. For Hurricane Odile, which hit the state of Baja California Sur
(BCS) in Mexico between 15 and 17 September 2014, we measured and mapped
communities' economic recovery time, which ranged from 2 to 40 days in
different locations. We found that -- among individuals with a bank account --
the lower the income level, the shorter the time needed for economic activity
to return to normal levels. Gender differences in recovery times were also
detected and quantified. In addition, our approach evaluated how communities
prepared for the disaster by quantifying expenditure growth in food or gasoline
before the hurricane struck. We believe this approach opens a new frontier in
measuring the economic impact of disasters with high temporal and spatial
resolution, and in understanding how populations bounce back and adapt.


title: Machine Learning Techniques for Stackelberg Security Games: a Survey

abstract:
  The present survey aims at presenting the current machine learning techniques
employed in security games domains. Specifically, we focused on papers and
works developed by the Teamcore of University of Southern California, which
deepened different directions in this field. After a brief introduction on
Stackelberg Security Games (SSGs) and the poaching setting, the rest of the
work presents how to model a boundedly rational attacker taking into account
her human behavior, then describes how to face the problem of having attacker's
payoffs not defined and how to estimate them and, finally, presents how online
learning techniques have been exploited to learn a model of the attacker.


title:
Excitation functions for(d,x)reactions on $^{133}$Cs up to $E_d = 40$
  MeV

abstract:
  In the frame of a systematic study of excitation functions of deuteron
induced reactions the excitation functions of the
$^{133}$Cs(d,x)$^{133m,133mg,131mg}$Ba, ${134,132}$Cs and $^{129m}$Xe nuclear
reactions were measured up to 40 MeV deuteron energies by using the stacked
foil irradiation technique and $\gamma$-ray spectroscopy of activated samples.
The results were compared with calculations performed with the theoretical
nuclear reaction codes ALICE-IPPE-D, EMPIRE II-D and TALYS calculation listed
in the TENDL-2014 library. A moderate agreement was obtained. Based on the
integral yields deduced from our measured cross sections, production of
$^{131}$Cs via the $^{133}$Cs(d,4n)$^{131}$Ba $\longrightarrow$ $^{131}$Cs
reaction and $^{133}$Ba via $^{133}$Cs(d,2n) reactions is discussed in
comparison with other charged particle production routes.


title: On some Galois covers of the Suzuki and Ree curves

abstract:
  We determine the full automorphism group of two recently constructed families
$\tilde{\mathcal{S}}_q$ and $\tilde{\mathcal{R}}_q$ of maximal curves over
finite fields. These curves are covers of the Suzuki and Ree curves, and are
analogous to the Giulietti-Korchm\'aros cover of the Hermitian curve. We also
show that $\tilde{\mathcal{S}}_q$ is not Galois covered by the Hermitian curve
maximal over $\mathbb{F}_{q^4}$, and $\tilde{\mathcal{R}}_q$ is not Galois
covered by the Hermitian curve maximal over $\mathbb{F}_{q^6}$. Finally, we
compute the genera of many Galois subcovers of $\tilde{\mathcal{S}}_q$ and
$\tilde{\mathcal{R}}_q$; this provides new genera for maximal curves.


title:
Clean Numerical Simulation: A New Strategy to Obtain Reliable Solutions
  of Chaotic Dynamic Systems

abstract:
  It is well known that chaotic dynamic systems (such as three-body system,
turbulent flow and so on) have the sensitive dependence on initial conditions
(SDIC). Unfortunately, numerical noises (such as truncation error and round-off
error) always exist in practice. Thus, due to the SDIC, long-term accurate
prediction of chaotic dynamic systems is practically impossible. In this paper,
a new strategy for chaotic dynamic systems, i.e. the Clean Numerical Simulation
(CNS), is briefly described, together with its applications to a few
Hamiltonian chaotic systems. With negligible numerical noises, the CNS can
provide convergent (reliable) chaotic trajectories in a long enough interval of
time. This is very important for Hamiltonian systems such as three-body
problem, and thus should have many applications in various fields. We find that
the traditional numerical methods in double precision cannot give not only
reliable trajectories but also reliable Fourier power spectra and
autocorrelation functions. In addition, it is found that even statistic
properties of chaotic systems can not be correctly obtained by means of
traditional numerical algorithms in double precision, as long as these
statistics are time-dependent. Thus, our CNS results strongly suggest that one
had better to be very careful on DNS results of statistically unsteady
turbulent flows, although DNS results often agree well with experimental data
when turbulent flows are in a statistical stationary state.


title:
An Unsupervised Method for Quantifying the Behavior of Interacting
  Individuals

abstract:
  Social behaviors involving the interaction of multiple individuals are
complex and frequently crucial for an animal's survival. These interactions,
ranging across sensory modalities, length scales, and time scales, are often
subtle and difficult to quantify. Contextual effects on the frequency of
behaviors become even more difficult to quantify when physical interaction
between animals interferes with conventional data analysis, e.g. due to visual
occlusion. We introduce a method for quantifying behavior in courting fruit
flies that combines high-throughput video acquisition and tracking of
individuals with recent unsupervised methods for capturing an animal's entire
behavioral repertoire. We find behavioral differences in paired and solitary
flies of both sexes, identifying specific behaviors that are affected by social
and spatial context. Our pipeline allows for a comprehensive description of the
interaction between multiple individuals using unsupervised machine learning
methods, and will be used to answer questions about the depth of complexity and
variance in fruit fly courtship.


title: Scattering problems in elastodynamics

abstract:
  In electromagnetism, acoustics, and quantum mechanics, scattering problems
can routinely be solved numerically by virtue of perfectly matched layers
(PMLs) at simulation domain boundaries. Unfortunately, the same has not been
possible for general elastodynamic wave problems in continuum mechanics. In
this paper, we introduce a corresponding scattered-field formulation for the
Navier equation. We derive PMLs based on complex-valued coordinate
transformations leading to Cosserat elasticity-tensor distributions not obeying
the minor symmetries. These layers are shown to work in two dimensions, for all
polarizations, and all directions. By adaptative choice of the decay length,
the deep subwavelength PMLs can be used all the way to the quasi-static regime.
As demanding examples, we study the effectiveness of cylindrical elastodynamic
cloaks of the Cosserat type and approximations thereof.

categories: physics.comp-ph math-ph math.MP physics.class-ph


title:
Dynamics of fragmentation and multiple vacancy generation in irradiated
  single-walled carbon nanotubes

abstract:
  The results from mass spectrometry of clusters sputtered from Cs+ irradiated
single-walled carbon nano-tubes (SWCNTs) as a function of energy and dose
identify the nature of the resulting damage in the form of multiple vacancy
generation. For pristine SWCNTs at all Cs+ energies, C2 is the most dominant
species, followed by C3, C4 and C1. The experiments were performed in three
stages: in the first stage, Cs+ energy E(Cs+) was varied. During the second
stage, the nanotubes were irradiated continuously at E(Cs+) = 5 keV for 1,800
s. Afterwards, the entire sequence of irradiation energies was repeated to
differentiate between the fragmentation patterns of the pristine and of heavily
irradiated SWCNTs. The sputtering and normalized yields identify the
quantitative and relative extent of the ion-induced damage by creating double,
triple and quadruple vacancies; the single vacancies are least favored.
Sputtering from the heavily irradiated SWCNTs occurs not only from the damaged
and fragmented nanotubes, but also from the inter-nanotube structures that are
grown due to the accumulation of the sputtered clusters. Similar irradiation
experiments were performed with the multi-walled carbon nanotubes; the results
confirmed the dominant C2 followed by C3, C4 and C1.


title:
Kinetics of Ferromagnetic Ordering in 3D Ising Model: Do we understand
  the case of zero temperature quench?

abstract:
  We study phase ordering dynamics in the three-dimensional nearest-neighbor
Ising model, following rapid quenches from infinite to zero temperature.
Results on various aspects, viz., domain growth, persistence, aging and
pattern, have been obtained via the Glauber Monte Carlo simulations of the
model on simple cubic lattice. These are analyzed via state-of-the-art methods,
including the finite-size scaling, and compared with those for quenches to a
temperature above the roughening transition. Each of these properties exhibit
remarkably different behavior at the above mentioned final temperatures. Such a
temperature dependence is absent in the two-dimensional case for which there is
no roughening transition.


title: An analysis of the LIGO discovery based on Introductory Physics

abstract:
  Binary black hole mergers are analyzed using concepts from introductory
physics. Drawing upon Newtonian mechanics, dimensional considerations, and
analogies between gravitational and electromagnetic waves, we are able to
explain the principal features of LIGO's data and make order of magnitude
estimates of key parameters of the event by inspection of the data. Our
estimates of the black hole masses, the distance to the event, the initial
separation of the pair, and the stupendous total amount of energy radiated are
all in good agreement with the best fit values of these parameters obtained by
the LIGO-VIRGO collaboration.


title: Level rearrangement in exotic-atom-like three-body systems

abstract:
  We study systems of three bosons bound by a long-range interaction
supplemented by a short-range potential of variable strength. This generalizes
the usual two-body exotic atoms where the Coulomb interaction is modified by
nuclear forces at short distances. The energy shift due to the short-range part
of the interaction combines two-body terms similar to the ones entering the
Trueman-Deser formula, and three-body contributions. A sudden variation of the
energy levels is observed near the coupling thresholds of the short-range
potential. But the patterns of rearrangement are significantly modified as
compared to the two-body case.


title:
Lost chapter of Physical Chemistry means convergence between Fisher
  Kolmogorov equation and tunnel effect

abstract:
  In this work we show that the dynamics of chemical reactions of order zero,
one and two have a representation through logistics probability. This
probability is robust, stable and complies systemically with the differential
equation of Fisher Kolmogorov (F K). It is robust, because in theorem 1 and
theorem 3 differential equations of diffusion and heat transfer are obtained,
where the temperature plays a key role. Also, the Eikonal equation of wave
mechanics allows us to construct the heat equation. In Lemma 2, Fick diffusion
equation is demonstrated. It is stable, because probability convergence when t
converge infinitum, gives us new ways to analyze the kinetics of a reaction
integrally, in Corollary 5. Finally, the theoretically and experimentally
obtained algorithms and results support the convergence in probability of the
quantum tunnel effect and chemical reactions for: hydrogen production at ultra
low temperature and catalytic cracking of asphalt at high temperature.


title: Calibrated representations of affine Yokonuma-Hecke algebras

abstract:
  Inspired by the work [Ra1], we directly give a complete classification of
irreducible calibrated representations of affine Yokonuma-Hecke algebras
$\widehat{Y}_{r,n}(q)$ over $\mathbb{C},$ which are indexed by $r$-tuples of
placed skew shapes. We then develop several applications of this result. In the
appendix, inspired by [Ru], we classify and construct irreducible completely
splittable representations of degenerate affine Yokonuma-Hecke algebras
$D_{r,n}$ and the wreath product $(\mathbb{Z}/r\mathbb{Z})\wr \mathfrak{S}_{n}$
over an algebraically closed field of characteristic $p> 0$ such that $p$ does
not divide $r$.


title: Deep Multi-Species Embedding

abstract:
  Understanding how species are distributed across landscapes over time is a
fundamental question in biodiversity research. Unfortunately, most species
distribution models only target a single species at a time, despite strong
ecological evidence that species are not independently distributed. We propose
Deep Multi-Species Embedding (DMSE), which jointly embeds vectors corresponding
to multiple species as well as vectors representing environmental covariates
into a common high-dimensional feature space via a deep neural network. Applied
to bird observational data from the citizen science project \textit{eBird}, we
demonstrate how the DMSE model discovers inter-species relationships to
outperform single-species distribution models (random forests and SVMs) as well
as competing multi-label models. Additionally, we demonstrate the benefit of
using a deep neural network to extract features within the embedding and show
how they improve the predictive performance of species distribution modelling.
An important domain contribution of the DMSE model is the ability to discover
and describe species interactions while simultaneously learning the shared
habitat preferences among species. As an additional contribution, we provide a
graphical embedding of hundreds of bird species in the Northeast US.


title:
The influence of numerical noises on statistics computation of chaotic
  dynamic systems

abstract:
  It is well known that chaotic dynamic systems (such as three-body system,
turbulent flow and so on) have the sensitive dependance on initial conditions
(SDIC). Unfortunately, numerical noises (such as truncation error and round-off
error) always exist in practice. Thus, due to the SDIC, long-term accurate
prediction of chaotic dynamic systems is practically impossible, and therefore
numerical simulations of chaos are only mixtures of "true" solution with
physical meanings and numerical noises without physical meanings. However, it
is traditionally believed that statistic computations based on such kind of
"mixtures" of numerical simulations of chaotic dynamic systems are acceptable.
In this paper, using the so-called "clean numerical simulation" (CNS) whose
numerical noises might be much smaller even than micro-level physical
uncertainty and thus are negligible, we gain accurate prediction of a chaotic
dynamic system in a long enough interval of time. Then, based on these reliable
simulations, the influence of numerical noises on statistic computations is
investigated. It is found that the influence of numerical noises is negligible
when statistic results are time-independent. Unfortunately, when a chaotic
dynamic system is far from equilibrium state so that its statistics are
time-dependent, numerical noises have a great influence even on statistic
computations. It suggests that even the direct numerical simulations (DNS)
might not give reliable statistic computations for non-equilibrium dynamic
systems with the SDIC.


title: Astrobiological Effects of Gamma-Ray Bursts in the Milky Way Galaxy

abstract:
  A planet having protective ozone within the collimated beam of a Gamma Ray
Burst (GRB) may suffer ozone depletion, potentially causing a mass extinction
event to existing life on a planet's surface and oceans. We model the dangers
of long GRBs to planets in the Milky Way and utilize a static statistical model
of the Galaxy that matches major observable properties, such as the inside-out
star formation history, metallicity evolution, and 3-dimensional stellar number
density distribution. The GRB formation rate is a function of both the star
formation history and metallicity; however, the extent to which chemical
evolution reduces the GRB rate over time in the Milky Way is still an open
question. Therefore, we compare the damaging effects of GRBs to biospheres in
the Milky Way using two models. One model generates GRBs as a function of the
inside-out star formation history. The other model follows the star formation
history, but generates GRB progenitors as a function of metallicity, thereby
favoring metal-poor host regions of the Galaxy over time. If the GRB rate only
follows the star formation history, the majority of the GRBs occur in the inner
Galaxy. However, if GRB progenitors are constrained to low metallicity
environments, then GRBs only form in the metal-poor outskirts at recent epochs.
Interestingly, over the past 1 Gyr, the surface density of stars (and their
corresponding planets) that survive a GRB is still greatest in the inner galaxy
in both models. The present day danger of long GRBs to life at the solar radius
($R_\odot=8$ kpc) is low. We find that at least $\sim$65% of stars survive a
GRB over the past 1 Gyr. Furthermore, when the GRB rate was expected to have
been enhanced at higher redshifts, such as $z\gtrsim0.5$, our results suggest
that a large fraction of planets would have survived these lethal GRB events.


title: Diophantine m-tuples in finite fields and modular forms

abstract:
  For a prime p, a Diophantine m-tuple in $\mathbb{F}_p$ is a set of m nonzero
elements of $\mathbb{F}_p$ with the property that the product of any two of its
distinct elements is one less than a square.
  In this paper, we present formulas for the number $N^{(m)}(p)$ of Diophantine
m-tuples in $\mathbb{F}_p$ for m=2,3 and 4. Fourier coefficients of certain
modular forms appear in the formula for the number of Diophantine quadruples.
  We prove that asymptotically $N^{(m)}(p)=\frac{1}{2^{m \choose 2
}}\frac{p^m}{m!} + o(p^m)$, and also show that if $p>2^{2m-2}m^2$, then there
is at least one Diophantine m-tuple in $\mathbb{F}_p$.


title: Morse theory for the uniform energy

abstract:
  In this paper we develop a Morse theory for the uniform energy. We use the
one-sided directional derivative of the distance function to study the
minimizing properties of variations through closed geodesics. This derivative
is then used to define a one-sided directional derivative for the uniform
energy which allows us to identify gradient-like vectors at those points where
the function is not differentiable. These vectors are used to restart the
standard negative gradient flow of the Morse energy at its critical points. We
illustrate this procedure on the flat torus and demonstrate that the restarted
flow improves the minimizing properties of the associated closed geodesics.


title:
Combining Belief Propagation and Successive Cancellation List Decoding
  of Polar Codes on a GPU Platform

abstract:
  The decoding performance of polar codes strongly depends on the decoding
algorithm used, while also the decoder throughput and its latency mainly depend
on the decoding algorithm. In this work, we implement the powerful successive
cancellation list (SCL) decoder on a GPU and identify the bottlenecks of this
algorithm with respect to parallel computing and its difficulties. The inherent
serial decoding property of the SCL algorithm naturally limits the achievable
speed-up gains on GPUs when compared to CPU implementations. In order to
increase the decoding throughput, we use a hybrid decoding scheme based on the
belief propagation (BP) decoder, which can be intra and inter-frame
parallelized. The proposed scheme combines excellent decoding performance and
high throughput within the signal-to-noise ratio (SNR) region of interest.


title: Don't Skype & Type! Acoustic Eavesdropping in Voice-Over-IP

abstract:
  Acoustic emanations of computer keyboards represent a serious privacy issue.
As demonstrated in prior work, physical properties of keystroke sounds might
reveal what a user is typing. However, previous attacks assumed relatively
strong adversary models that are not very practical in many real-world
settings. Such strong models assume: (i) adversary's physical proximity to the
victim, (ii) precise profiling of the victim's typing style and keyboard,
and/or (iii) significant amount of victim's typed information (and its
corresponding sounds) available to the adversary.
  This paper presents and explores a new keyboard acoustic eavesdropping attack
that involves Voice-over-IP (VoIP), called Skype & Type (S&T), while avoiding
prior strong adversary assumptions. This work is motivated by the simple
observation that people often engage in secondary activities (including typing)
while participating in VoIP calls. As expected, VoIP software acquires and
faithfully transmits all sounds, including emanations of pressed keystrokes,
which can include passwords and other sensitive information. We show that one
very popular VoIP software (Skype) conveys enough audio information to
reconstruct the victim's input -- keystrokes typed on the remote keyboard. Our
results demonstrate that, given some knowledge on the victim's typing style and
keyboard model, the attacker attains top-5 accuracy of 91.7% in guessing a
random key pressed by the victim.
  Furthermore, we demonstrate that S&T is robust to various VoIP issues (e.g.,
Internet bandwidth fluctuations and presence of voice over keystrokes), thus
confirming feasibility of this attack. Finally, it applies to other popular
VoIP software, such as Google Hangouts.


title:
Radiation of Relativistic Particles in a Quasi-Homogeneous Magnetic
  Field

abstract:
  Spectrum of radiation of a relativistic particle moving in a nonhomogeneous
magnetic field is considered. The spectrum depends on the pitch-angle $\alpha$
between the velocity direction and a line tangent to the field line. In case of
very small $\alpha$ the particle generates so-called curvature radiation, in an
intermediate case undulator-kind radiation is produced. In this paper we
present the calculations of radiation properties in a case when both curvature
and undulator radiation is observed.


title: Microphysics in the gamma ray burst central engine

abstract:
  We calculate the structure and evolution of a gamma ray burst central engine
where an accreting torus has formed around the newly born black hole. We study
the general relativistic,MHD models and we self-consistently incorporate the
nuclear equation of state. The latter accounts for the degeneracy of
relativistic electrons, protons, and neutrons, and is used in the dynamical
simulation, instead of a standard polytropic -law. The EOS provides the
conditions for the nuclear pressure in the function of density and temperature,
which evolve with time according to the conservative MHD scheme. We analyze the
structure of the torus and outflowing winds, and compute the neutrino flux
emitted through the nuclear reactions balance in the dense and hot matter. We
also estimate the rate of transfer of the black hole rotational energy to the
bipolar jets. Finally, we elaborate on the nucleosynthesis of heavy elements in
the accretion flow and the wind, through computations of the thermonuclear
reaction network. We discuss the possible signatures of the radioactive
elements decay in the accretion flow. We suggest that further detailed modeling
of the accretion flow in GRB engine, together with its microphysics, may be a
valuable tool to constrain the black hole mass and spin. It can be
complementary to the gravitational wave analysis, if the waves are detected
with an electromagnetic counterpart.


title: Randall-Sundrum vs. Holographic Braneworld

abstract:
  A mapping between two braneworld cosmologies -- Randall-Sundrum and
holographic -- is explicitly constructed. The cosmologies are governed by the
appropriate modified Friedman equations. A relationship between the
corresponding Hubble rates is established.


title:
Microscopic Processes in Global Relativistic Jets Containing Helical
  Magnetic Fields

abstract:
  In the study of relativistic jets one of the key open questions is their
interaction with the environment on the microscopic level. Here, we study the
initial evolution of both electron$-$proton ($e^{-}-p^{+}$) and
electron$-$positron ($e^{\pm}$) relativistic jets containing helical magnetic
fields, focusing on their interaction with an ambient plasma. We have performed
simulations of "global" jets containing helical magnetic fields in order to
examine how helical magnetic fields affect kinetic instabilities such as the
Weibel instability, the kinetic Kelvin-Helmholtz instability (kKHI) and the
Mushroom instability (MI). In our initial simulation study these kinetic
instabilities are suppressed and new types of instabilities can grow. In the
$e^{-}-p^{+}$ jet simulation a recollimation-like instability occurs and jet
electrons are strongly perturbed. In the $e^{\pm}$ jet simulation a
recollimation-like instability occurs at early times followed by a kinetic
instability and the general structure is similar to a simulation without
helical magnetic field. Simulations using much larger systems are required in
order to thoroughly follow the evolution of global jets containing helical
magnetic fields.


title: Automatic semigroups vs automaton semigroups

abstract:
  We develop an effective and natural approach to interpret any semigroup
admitting a special language of greedy normal forms as an automaton
semigroup,namely the semigroup generated by a Mealy automaton encoding the
behaviour of such a language of greedy normal forms under one-sided
multiplication.The framework embraces many of the well-known classes of
(automatic) semigroups: finite monoids, free semigroups, free commutative
monoids, trace or divisibility monoids, braid or Artin-Tits or Krammer or
Garside monoids, Baumslag-Solitar semigroups, etc.Like plactic monoids or
Chinese monoids, some neither left- nor right-cancellative automatic semigroups
are also investigated, as well as some residually finite variations of the
bicyclic monoid. It provides what appears to be the first known connection from
a class of automatic semigroupsto a class of automaton semigroups. It is
worthwhile noting that, in all these cases, "being an automatic semigroup" and
"being an automaton semigroup" become dual properties in a very
automata-theoretical sense. Quadratic rewriting systems and associated tilings
appear as a cornerstone of our construction.


title:
Deep Tracking on the Move: Learning to Track the World from a Moving
  Vehicle using Recurrent Neural Networks

abstract:
  This paper presents an end-to-end approach for tracking static and dynamic
objects for an autonomous vehicle driving through crowded urban environments.
Unlike traditional approaches to tracking, this method is learned end-to-end,
and is able to directly predict a full unoccluded occupancy grid map from raw
laser input data. Inspired by the recently presented DeepTracking approach
[Ondruska, 2016], we employ a recurrent neural network (RNN) to capture the
temporal evolution of the state of the environment, and propose to use Spatial
Transformer modules to exploit estimates of the egomotion of the vehicle. Our
results demonstrate the ability to track a range of objects, including cars,
buses, pedestrians, and cyclists through occlusion, from both moving and
stationary platforms, using a single learned model. Experimental results
demonstrate that the model can also predict the future states of objects from
current inputs, with greater accuracy than previous work.


title:
Numerical and analytical approaches to an advection-diffusion problem at
  small Reynolds number and large P\'eclet number

abstract:
  Obtaining a detailed understanding of the physical interactions between a
cell and its environment often requires information about the flow of fluid
surrounding the cell. Cells must be able to effectively absorb and discard
material in order to survive. Strategies for nutrient acquisition and toxin
disposal, which have been evolutionarily selected for their efficacy, should
reflect knowledge of the physics underlying this mass transport problem.
Motivated by these considerations, in this paper we discuss the results from an
undergraduate research project on the advection-diffusion equation at small
Reynolds number and large P\'eclet number. In particular, we consider the
problem of mass transport for a Stokesian spherical swimmer. We approach the
problem numerically and analytically through a rescaling of the concentration
boundary layer. A biophysically motivated first-passage problem for the
absorption of material by the swimming cell demonstrates quantitative agreement
between the numerical and analytical approaches. We conclude by discussing the
connections between our results and the design of smart toxin disposal systems.


title:
Dephasing enhanced spin transport in the ergodic phase of a many-body
  localizable system

abstract:
  We study high temperature spin transport in a disordered Heisenberg chain in
the ergodic regime when bulk dephasing is present. We find that while dephasing
always renders the transport diffusive, there is nonetheless a remnant of the
diffusive to sub-diffusive transition found in a system without dephasing
manifested in the behaviour of the diffusion constant with the dephasing
strength. By studying finite-size effects we show numerically and theoretically
that this feature is caused by the competition between large crossover length
scales associated to disorder and dephasing that control the dynamics observed
in the thermodynamic limit. We demonstrate that this competition may lead to a
dephasing enhanced transport in this model.