title:
Minkowski measurability criteria for compact sets and relative fractal
  drums in Euclidean spaces

abstract:
  We establish a Minkowski measurability criterion for a large class of
relative fractal drums (or, in short, RFDs), in Euclidean spaces of arbitrary
dimension in terms of their complex dimensions, which are defined as the poles
of their associated fractal zeta functions. Relative fractal drums represent a
far-reaching generalization of bounded subsets of Euclidean spaces as well as
of fractal strings studied extensively by the first author and his
collaborators. In fact, the Minkowski measurability criterion established here
is a generalization of the corresponding one obtained for fractal strings by
the first author and M.\ van Frankenhuijsen. Similarly as in the case of
fractal strings, the criterion established here is formulated in terms of the
locations of the principal complex dimensions associated with the relative drum
under consideration. These complex dimensions are defined as poles or, more
generally, singularities of the corresponding distance (or tube) zeta function.
We also reflect on the notion of gauge-Minkowski measurability of RFDs and
establish several results connecting it to the nature and location of the
complex dimensions. (This is especially useful when the underlying scaling does
not follow a classic power law.) We illustrate our results and their
applications by means of a number of interesting examples.


title:
On the Security of Millimeter Wave Vehicular Communication Systems using
  Random Antenna Subsets

abstract:
  Millimeter wave (mmWave) vehicular communica tion systems have the potential
to improve traffic efficiency and safety. Lack of secure communication links,
however, may lead to a formidable set of abuses and attacks. To secure
communication links, a physical layer precoding technique for mmWave vehicular
communication systems is proposed in this paper. The proposed technique
exploits the large dimensional antenna arrays available at mmWave systems to
produce direction dependent transmission. This results in coherent transmission
to the legitimate receiver and artificial noise that jams eavesdroppers with
sensitive receivers. Theoretical and numerical results demonstrate the validity
and effectiveness of the proposed technique and show that the proposed
technique provides high secrecy throughput when compared to conventional array
and switched array transmission techniques.


title: Cellular stratified spaces

abstract:
  The notion of cellular stratified spaces was introduced in a joint work of
the author with Basabe, Gonz{\'a}lez, and Rudyak with the aim of constructing a
cellular model of the configuration space of a sphere. Although the original
aim was not achieved in the project, the notion of cellular stratified spaces
turns out to be useful, at least, in the study of configuration spaces of
graphs. In particular, the notion of totally normal cellular stratified spaces
was used successfully in a joint work with the former students of the author
arXiv:1312.7368 to study the homotopy type of configuration spaces of graphs
with a small number of vertices. Roughly speaking, totally normal cellular
stratified spaces correspond to acyclic categories in the same way regular cell
complexes correspond to posets. In this paper, we extend this correspondence by
replacing cells by stellar cells and acyclic categories by topological acyclic
categories.


title:
The complex Langevin analysis of spontaneous symmetry breaking induced
  by complex fermion determinant

abstract:
  In many interesting physical systems, the determinant which appears from
integrating out fermions becomes complex, and its phase plays a crucial role in
the determination of the vacuum. An example of this is QCD at low temperature
and high density, where various exotic fermion condensates are conjectured to
form. Another example is the Euclidean version of the type IIB matrix model for
10d superstring theory, where spontaneous breaking of the SO(10) rotational
symmetry down to SO(4) is expected to occur. When one applies the complex
Langevin method to these systems, one encounters the singular-drift problem
associated with the appearance of nearly zero eigenvalues of the Dirac
operator. Here we propose to avoid this problem by deforming the action with a
fermion bilinear term. The results for the original system are obtained by
extrapolations with respect to the deformation parameter. We demonstrate the
power of this approach by applying it to a simple matrix model, in which
spontaneous symmetry breaking from SO(4) to SO(2) is expected to occur due to
the phase of the complex fermion determinant. Unlike previous work based on a
reweighting-type method, we are able to determine the true vacuum by
calculating the order parameters, which agree with the prediction by the
Gaussian expansion method.


title:
Catastrophes in non-equilibrium many-particle wave functions:
  universality and critical scaling

abstract:
  As part of the quest to uncover universal features of quantum dynamics, we
study catastrophes that form in simple many-body wave functions after a quench,
focusing on two-mode systems that include the two-site Bose Hubbard model, and
under some circumstances optomechanical systems and the Dicke model. When the
wave function is plotted in Fock space plus time certain characteristic
structures generically appear that we identify as cusp caustics. In the
vicinity of such a catastrophe the wave function takes on a universal form
described by the Pearcey function and obeys scaling relations which depend on
the total number of particles $N$. In the thermodynamic limit ($N \rightarrow
\infty$) the cusp becomes singular, but at finite $N$ it is decorated by an
interference pattern. This pattern contains an intricate network of
vortex-antivortex pairs, initiating a theory of topological structures in Fock
space. In the case where the quench takes the form of a $\delta$-kick we show
how to analytically map the wave function onto the Pearcey function and hence
obtain the scaling exponents for the size and position of the cusp, as well as
those for the amplitude and characteristic length scales of its interference
pattern.


title:
Measurement of the omega -> pi^0 e^+e^- and eta -> e^+e^-g Dalitz decays
  with the A2 setup at MAMI

abstract:
  The Dalitz decays eta -> e^+e^-g and omega -> pi^0 e^+e^- have been measured
in the g p -> eta p and g p -> omega p reactions, respectively, with the A2
tagged-photon facility at the Mainz Microtron, MAMI. The value obtained for the
slope parameter of the electromagnetic transition form factor of eta,
Lambda^{-2}_eta=(1.97+/-0.11_tot) GeV^{-2}, is in good agreement with previous
measurements of the eta -> e^+e^-g and eta -> mu^+mu^-g decays. The uncertainty
obtained in the value of Lambda^{-2}_eta is lower than in previous results
based on the eta -> e^+e^-g decay. The value obtained for the omega slope
parameter, Lambda^{-2}_omega_pi^0 = (1.99+/-0.21_tot) GeV^{-2}, is somewhat
lower than previous measurements based on omega -> pi^0 mu^+mu^-, but the
results for the omega transition form factor are in better agreement with
theoretical calculations, compared to earlier experiments.


title: cesium: Open-Source Platform for Time-Series Inference

abstract:
  Inference on time series data is a common requirement in many scientific
disciplines and internet of things (IoT) applications, yet there are few
resources available to domain scientists to easily, robustly, and repeatably
build such complex inference workflows: traditional statistical models of time
series are often too rigid to explain complex time domain behavior, while
popular machine learning packages require already-featurized dataset inputs.
Moreover, the software engineering tasks required to instantiate the
computational platform are daunting. cesium is an end-to-end time series
analysis framework, consisting of a Python library as well as a web front-end
interface, that allows researchers to featurize raw data and apply modern
machine learning techniques in a simple, reproducible, and extensible way.
Users can apply out-of-the-box feature engineering workflows as well as save
and replay their own analyses. Any steps taken in the front end can also be
exported to a Jupyter notebook, so users can iterate between possible models
within the front end and then fine-tune their analysis using the additional
capabilities of the back-end library. The open-source packages make us of many
use modern Python toolkits, including xarray, dask, Celery, Flask, and
scikit-learn.


title:
Optimized pulses for Raman excitation through the continuum:
  verification using multi-configurational time-dependent Hartree-Fock

abstract:
  We have verified a mechanism for Raman excitation of atoms through continuum
levels previously obtained by quantum optimal control using the
multi-configurational time-dependent Hartree-Fock (MCTDHF) method. For the
optimal control, which requires running multiple propagations to determine the
optimal pulse sequence, we used the computationally inexpensive time-dependent
configuration interaction singles (TDCIS) method. TDCIS captures all of the
necessary correlation of the desired processes but assumes that ionization
pathways reached via double excitations are not present. MCTDHF includes these
pathways and all multiparticle correlations in a set of time-dependent
orbitals. The mechanism that was determined to be optimal in the Raman
excitation of the Ne $1s^22s^22p^53p^1$ valence state via the metastable
$1s^22s^12p^63p^1$ resonance state involves a sequential resonance-valence
excitation. First, a long pump pulse excites the core-hole state, and then a
shorter Stokes pulse transfers the population to the valence state. This
process represents the first step in a multidimensional x-ray spectroscopy
scheme that will provide a local probe of valence electronic correlations.
Although at the optimal pulse intensities at the TDCIS level of theory the
MCTDHF method predicts multiple ionization of the atom, at slightly lower
intensities (reduced by a factor of about 4) the TDCIS mechanism is shown to
hold qualitatively. Quantitatively, the MCTDHF populations are reduced from the
TDCIS calculations by a factor of 4.


title:
Robust residual-based a posteriori error estimators for mixed finite
  element methods for fourth order elliptic singularly perturbed problems

abstract:
  We consider mixed finite element approximation of a singularly perturbed
fourth-order elliptic problem with two different boundary conditions, and
present a new measure of the error, whose components are balanced with respect
to the perturbation parameter. Robust residual-based a posteriori estimators
for the new measure are obtained, which are achieved via a novel analytical
technique based on an approximation result. Numerical examples are presented to
validate our theory.


title: Matroidal Schur Algebras

abstract:
  Fix a principal ideal domain $k$. In this article we associate to a
(weighted) matroid $M$ a quasi-hereditary algebra $R(M)$ defined over $k$ such
that matroid duality corresponds to Ringel duality of quasi-hereditary
algebras. The representation theory of these algebras is related to work of
Schechtman-Varchenko and Brylawski-Varchenko. In characteristic zero, our
algebras are also closely related to work of Kook-Reiner-Stanton and Denham.


title: Column Networks for Collective Classification

abstract:
  Relational learning deals with data that are characterized by relational
structures. An important task is collective classification, which is to jointly
classify networked objects. While it holds a great promise to produce a better
accuracy than non-collective classifiers, collective classification is
computational challenging and has not leveraged on the recent breakthroughs of
deep learning. We present Column Network (CLN), a novel deep learning model for
collective classification in multi-relational domains. CLN has many desirable
theoretical properties: (i) it encodes multi-relations between any two
instances; (ii) it is deep and compact, allowing complex functions to be
approximated at the network level with a small set of free parameters; (iii)
local and relational features are learned simultaneously; (iv) long-range,
higher-order dependencies between instances are supported naturally; and (v)
crucially, learning and inference are efficient, linear in the size of the
network and the number of relations. We evaluate CLN on multiple real-world
applications: (a) delay prediction in software projects, (b) PubMed Diabetes
publication classification and (c) film genre classification. In all
applications, CLN demonstrates a higher accuracy than state-of-the-art rivals.


title:
DDO216-A1: a central globular cluster in a low-luminosity transition
  type galaxy

abstract:
  We confirm that the object DDO216-A1 is a substantial globular cluster at the
center of Local Group galaxy DDO216 (the Pegasus dwarf irregular), using Hubble
Space Telescope ACS imaging. By fitting isochrones, we find the cluster
metallicity to be [M/H] = -1.6 +/-0.2, for reddening E(B-V) = 0.16 +/-0.02; the
best-fit age is 12.3 +/-0.8 Gyr. There are ~30 RR Lyrae variables in the
cluster; the magnitude of the fundamental mode pulsators gives a distance
modulus of 24.77 +/-0.08 - identical to the host galaxy. The ratio of overtone
to fundamental mode variables and their mean periods make DDO216-A1 an
Oosterhoff Type I cluster. We find an I-band central surface brightness 20.85
+/-0.17 F814W mag per square arcsecond, a half-light radius of 3.1 arcsec (13.4
pc), and an absolute magnitude M814 = -7.90 +/-0.16 (approximately 10^5 solar
masses). King models fit to the cluster give the core radius and concentration
index, r_c = 2.1" +/-0.9" and c = 1.24 +/-0.39. The cluster is an "extended"
cluster somewhat typical of some dwarf galaxies and the outer halo of the Milky
Way. The cluster is projected <30 pc south of the center of DDO216, unusually
central compared to most dwarf galaxy globular clusters. Analytical models of
dynamical friction and tidal destruction suggest that it probably formed at a
larger distance, up to ~1 kpc, and migrated inward. DDO216 has an unexceptional
cluster specific frequency, S_N = 10. DDO216 is the lowest-luminosity Local
Group galaxy to host a 10^5 solar mass globular cluster, and the only
transition-type (dSph/dIrr) in the Local Group with a globular.


title:
Optical spectroscopy of single beryllium acceptors in GaAs/AlGaAs
  quantum well

abstract:
  We carry out microphotoluminescence measurements of an acceptor-bound exciton
(A^0X) recombination in the applied magnetic field with a single impurity
resolution. In order to describe the obtained spectra we develop a theoretical
model taking into account a quantum well (QW) confinement, an electron-hole and
hole-hole exchange interaction. By means of fitting the measured data with the
model we are able to study the fine structure of individual acceptors inside
the QW. The good agreement between our experiments and the model indicates that
we observe single acceptors in a pure two-dimensional environment whose states
are unstrained in the QW plain.


title:
Ferromagnetism and the Effect of Free Charge Carriers on Electric
  Polarization in Y_2NiMnO_6 Double Perovskite

abstract:
  The double perovskite Y_2NiMnO_6 displays ferromagnetic transition at Tc = 81
K. The ferromagnetic order at low temperature is confirmed by the saturation
value of magnetization (M_s) and also, validated by the refined ordered
magnetic moment values extracted from neutron powder diffraction data at 10 K.
This way, the dominant Mn4+ and Ni2+ cationic ordering is confirmed. The
cation-ordered P 21/n nuclear structure is revealed by neutron powder
diffraction studies at 300 and 10 K. Analysis of frequency dependent dielectric
constant and equivalent circuit analysis of impedance data takes into account
the bulk contribution to total dielectric constant. This reveals an anomaly
which coincides with the ferromagnetic transition temperature (T_c).
Pyrocurrent measurements register a current flow with onset near Tc and a peak
at 57 K that shifts with temperature ramp rate. The extrinsic nature of the
observed pyrocurrent is established by employing a special protocol
measurement. It is realized that the origin is due to re-orientation of
electric dipoles created by the free charge carriers and not by spontaneous
electric polarization at variance with recently reported magnetism-driven
ferroelectricity in this material


title:
Scheduling Autonomous Vehicle Platoons Through an Unregulated
  Intersection

abstract:
  We study various versions of the problem of scheduling platoons of autonomous
vehicles through an unregulated intersection, where an algorithm must schedule
which platoons should wait so that others can go through, so as to minimize the
maximum delay for any vehicle. We provide polynomial-time algorithms for
constructing such schedules for a $k$-way merge intersection, for constant $k$,
and for a crossing intersection involving two-way traffic. We also show that
the more general problem of scheduling autonomous platoons through an
intersection that includes both a $k$-way merge, for non-constant $k$, and a
crossing of two-way traffic is NP-complete.


title: A projective analogue of Napoleon's and Varignon's theorems

abstract:
  What do Napoleon's and Varignon's theorems have in common? We claim that they
both are examples of immediately regularizing natural polygon iterations in
different planar geometries and present a new and analogous result in
projective geometry.


title:
Function-Based Access Control (FBAC): From Access Control Matrix to
  Access Control Tensor

abstract:
  Security researchers have stated that the core concept behind current
implementations of access control predates the Internet. These assertions are
made to pinpoint that there is a foundational gap in this field, and one should
consider revisiting the concepts from the ground up. Moreover, Insider threats,
which are an increasing threat vector against organizations are also associated
with the failure of access control. Access control models derived from access
control matrix encompass three sets of entities, Subjects, Objects and
Operations. Typically, objects are considered to be files and operations are
regarded as Read, Write, and Execute. This implies an `open sesame' approach
when granting access to data, i.e. once access is granted, there is no
restriction on command executions. Inspired by Functional Encryption, we
propose applying access authorizations at a much finer granularity, but instead
of an ad-hoc or computationally hard cryptographic approach, we postulate a
foundational transformation to access control. From an abstract viewpoint, we
suggest storing access authorizations as a three-dimensional tensor, which we
call Access Control Tensor (ACT). In Function-based Access Control (FBAC),
applications do not give blind folded execution right and can only invoke
commands that have been authorized for data segments. In other words, one might
be authorized to use a certain command on one object, while being forbidden to
use exactly the same command on another object. The theoretical foundations of
FBAC are presented along with Policy, Enforcement and Implementation (PEI)
requirements of it. A critical analysis of the advantages of deploying FBAC,
how it will result in developing a new generation of applications, and
compatibility with existing models and systems is also included. Finally, a
proof of concept implementation of FBAC is presented.


title: Membrane tubulation by elongated and patchy nanoparticles

abstract:
  Advances in nanotechnology lead to an increasing interest in how
nanoparticles interact with biomembranes. Nanoparticles are wrapped
spontaneously by biomembranes if the adhesive interactions between the
particles and membranes compensate for the cost of membrane bending. In the
last years, the cooperative wrapping of spherical nanoparticles in membrane
tubules has been observed in experiments and simulations. For spherical
nanoparticles, the stability of the particle-filled membrane tubules strongly
depends on the range of the adhesive particle-membrane interactions. In this
article, we show via modeling and energy minimization that elongated and patchy
particles are wrapped cooperatively in membrane tubules that are highly stable
for all ranges of the particle-membrane interactions, compared to individual
wrapping of the particles. The cooperative wrapping of linear chains of
elongated or patchy particles in membrane tubules may thus provide an efficient
route to induce membrane tubulation, or to store such particles in membranes.


title:
The Fermionic Signature Operator and Hadamard States in the Presence of
  a Plane Electromagnetic Wave

abstract:
  We give a non-perturbative construction of a distinguished state for the
quantized Dirac field in Minkowski space in the presence of a time-dependent
external field of the form of a plane electromagnetic wave. By explicit
computation of the fermionic signature operator, it is shown that the Dirac
operator has the strong mass oscillation property. We prove that the resulting
fermionic projector state is a Hadamard state.


title: Analytic study of singular curves

abstract:
  We study singular curves from analytic point of view. We give completely
analytic proofs for the Serre duality and a generalized Abel's theorem. We also
reconsider Picard varieties, Albanese varieties and generalized Jacobi
varieties of singular curves analytically. We call an Albanese variety
considered as a complex Lie group an analytic Albanese variety. We investigate
them in detail. For a non-singular curve (a compact Riemann surface) $X$, there
is the relation between the meromorphic function fields on $X$ and on its
Jacobi variety $J(X)$. We try to extend this relation to the case of singular
curves.


title:
Reference Physics Design for 1 GeV Injector Linac and Accumulator Ring
  for Indian Spallation Neutron Source

abstract:
  As a part of the ongoing XIIth plan project titled "R&D activities for high
energy proton linac based spallation neutron source", the work on physics
design of various subsystems of the injector linac and accumulator ring has
been taken up at RRCAT, Indore. For the 1 GeV H- injector linac, physics design
studies of individual systems have been completed, and the end to end beam
dynamics simulation studies have been performed to ensure that the stringent
beam dynamics criteria are satisfied for the optimized lattice. Physics design
studies to optimize the linear lattice of the accumulator ring have also been
completed. The design studies for the beam transport lines from the injector
linac to the accumulator ring, and from the accumulator ring to target are
currently in progress. This report describes the physics design of various
systems of the injector linac and the accumulator ring.


title:
Crossover from magnetostatic to exchange coupling in
  La0.67Ca0.33MnO3/YBa2Cu3O7/La0.67Ca0.33MnO3 heterostructures

abstract:
  The influence of YBa2Cu3O4 (YBCO) superconductor layer (S-layer) with varying
thickness d-YBCO = 20 to 50 nm on the magnetic coupling between two
La0.67Ca0.33MnO3 (LCMO) ferromagnet layers (F-layer, thickness d-LCMO = 50 nm)
in F/S/F heterostructures (HSs) was investigated by measuring global
magnetization (M) in a temperature (T) range = 2 - 300 K and magnetic field (H)
range = 0 - 10 kOe. All the HSs were superconducting with critical temperature
(Tc) decreasing from = 78 to 36 K with decrease in d-YBCO, whereas the
ferromagnetic ordering temperature Tm = 250 K did not change much.
Systematically measured M-H loops of all HSs at both T > Tc and T < Tc show
three main results- (a) the two step magnetic reversal above Tc converts into a
four step reversal below Tc in HSs with d-YBCO >= 30 nm, (b) the magnetic field
corresponding to the additional two switching steps and their magnitude show
characteristic evolution with T and d-YBCO and (c) the HS with d-YBCO = 20 nm
shows radically different behaviour, where the two step magnetic reversal above
Tc continues to persist below Tc and converts into a single step reversal at T
<< Tc. The first two results indicate magnetostatic coupling between the
magnetic domains and the vortices across the two F/S interfaces resulting in
reversal dynamics different from that deep within the LCMO layers. Whereas, the
result c reveals indirect exchange coupling between LCMO layers through the
superconducting YBCO layer, which is a clear experimental evidence of
coexistence of ferromagnetism and superconductivity in nm scale F/S/F HSs
expected theoretically by C.A.R. Sa de Melo (Physica C 387, 17-25 (2003)).


title: Detecting Sub-lunar Mass Compact Objects toward the Local Group Galaxies

abstract:
  By monitoring a large number of stars in the Local Group galaxies, we can
detect nanolensing events by sub-lunar mass compact objects (SULCOs) such as
primordial black holes (PBHs) and rogue (free-floating) dwarf planets in the
Milky Way halo. In contarst to microlensing by stellar-mass objects, the
finite-source size effect becomes important and the lensing time duration
becomes shorter ($\sim 10^{1-4}\,\textrm{s}$). Using stars with $V<26$ in M33
as sources, for one-night observation, we would be able to detect $10^{3-4}$
nanolensing events caused by SULCOs in the Milky Way halo with a mass of
$10^{-9}M_{\odot}$ to $10^{-7}M_{\odot}$ for sources with S/N$>5$ if SULCOs
constitute all the dark matter components. Moreover, we expect $10^{1-2}$
events in which bright blue stars with S/N$>100$ are weakly amplified due to
lensing by SULCOs with a mass range of $10^{-11}M_{\odot}$ to
$10^{-9}M_{\odot}$. Thus the method would open a new window on SULCOs in the
Milky Way halo that would otherwise not be observable.


title: C-Share: Optical Circuits Sharing for Software-Defined Data-Centers

abstract:
  Integrating optical circuit switches in data-centers is an on-going research
challenge. In recent years, state-of-the-art solutions introduce hybrid
packet/circuit architectures for different optical circuit switch technologies,
control techniques, and traffic rerouting methods. These solutions are based on
separated packet and circuit planes which do not have the ability to utilize an
optical circuit with flows that do not arrive from or delivered to switches
directly connected to the circuit's end-points. Moreover, current SDN-based
elephant flow rerouting methods require a forwarding rule for each flow, which
raise scalability issues. In this paper, we present C-Share -- a practical,
scalable SDN-based circuit sharing solution for data center networks. C-Share
inherently enable elephant flows to share optical circuits by exploiting a flat
upper tier network topology. C-Share is based on a scalable and decoupled
SDN-based elephant flow rerouting method comprised of elephant flow detection,
tagging and identification, which is utilized by using a prevalent network
sampling method (e.g., sFlow). C-Share requires only a single OpenFlow rule for
each optical circuit, and therefore significantly reduces the required OpenFlow
rule entry footprint and setup rule rate. It also mitigates the OpenFlow
outbound latency for subsequent elephant flows. We implement a proof-of-concept
system for C-Share based on Mininet, and test the scalability of C-Share by
using an event driven simulation. Our results show a consistent increase in the
mice/elephant flow separation in the network which, in turn, improves both
network throughput and flow completion time.


title:
Tensor Graphical Model: Non-convex Optimization and Statistical
  Inference

abstract:
  We consider the estimation and inference of graphical models that
characterize the dependency structure of high-dimensional tensor-valued data.
To facilitate the estimation of the precision matrix corresponding to each way
of the tensor, we assume the data follow a tensor normal distribution whose
covariance has a Kronecker product structure. A critical challenge in the
estimation and inference of this model is the fact that its penalized maximum
likelihood estimation involves minimizing a non-convex objective function. To
address it, this paper makes two contributions: (i) In spite of the
non-convexity of this estimation problem, we prove that an alternating
minimization algorithm, which iteratively estimates each sparse precision
matrix while fixing the others, attains an estimator with an optimal
statistical rate of convergence. (ii) We propose a de-biased statistical
inference procedure for testing hypotheses on the true support of the sparse
precision matrices, and employ it for testing a growing number of hypothesis
with false discovery rate (FDR) control. The asymptotic normality of our test
statistic and the consistency of FDR control procedure are established. Our
theoretical results are backed up by thorough numerical studies and our real
applications on neuroimaging studies of Autism spectrum disorder and users'
advertising click analysis bring new scientific findings and business insights.
The proposed methods are encoded into a publicly available R package Tlasso.


title: STORE: Sparse Tensor Response Regression and Neuroimaging Analysis

abstract:
  Motivated by applications in neuroimaging analysis, we propose a new
regression model, Sparse TensOr REsponse regression (STORE), with a tensor
response and a vector predictor. STORE embeds two key sparse structures:
element-wise sparsity and low-rankness. It can handle both a non-symmetric and
a symmetric tensor response, and thus is applicable to both structural and
functional neuroimaging data. We formulate the parameter estimation as a
non-convex optimization problem, and develop an efficient alternating updating
algorithm. We establish a non-asymptotic estimation error bound for the actual
estimator obtained from the proposed algorithm. This error bound reveals an
interesting interaction between the computational efficiency and the
statistical rate of convergence. When the distribution of the error tensor is
Gaussian, we further obtain a fast estimation error rate which allows the
tensor dimension to grow exponentially with the sample size. We illustrate the
efficacy of our model through intensive simulations and an analysis of the
Autism spectrum disorder neuroimaging data.


title: Geometric control theory for quantum back-action evasion

abstract:
  Engineering a sensor system for detecting an extremely tiny signal such as
the gravitational-wave force is a very important subject in quantum physics. A
major obstacle to this goal is that, in a simple detection setup, the
measurement noise is lower bounded by the so-called standard quantum limit
(SQL), which is originated from the intrinsic mechanical back-action noise.
Hence, the sensor system has to be carefully engineered so that it evades the
back-action noise and eventually beats the SQL. In this paper, based on the
well-developed geometric control theory for classical disturbance decoupling
problem, we provide a general method for designing an auxiliary (coherent
feedback or direct interaction) controller for the sensor system to achieve the
above-mentioned goal. This general theory is applied to a typical
opto-mechanical sensor system. Also, we demonstrate a controller design for a
practical situation where several experimental imperfections are present.


title: The (cyclic) enhanced nilpotent cone via quiver representations

abstract:
  The $\mathrm{GL}(V)$-orbits in the enhanced nilpotent cone
$V\times\mathcal{N}(V)$ are (essentially) in bijection with the orbits of a
certain parabolic $P\subseteq\mathrm{GL}(V)$ (the mirabolic subgroup) in the
nilpotent cone $\mathcal{N}(V)$. We give a new parameterization of the orbits
in the enhanced nilpotent cone, in terms of representations of the underlying
quiver. This parameterization generalizes naturally to the enhanced cyclic
nilpotent cone. Our parameterizations are different to the previous ones that
have appeared in the literature. Explicit translations between the different
parametrizations are given.


title: Route toward high-speed nano-magnonics

abstract:
  We study experimentally the possibility to utilize pulses of pure spin
current, produced via the nonlocal spin injection mechanism, to generate short
packets of spin waves propagating in nanoscale magnetic waveguides. The
spatially and time-resolved micro-focus Brillouin light scattering spectroscopy
measurements demonstrate that the excitation by spin current results in
extremely fast transient response, enabling efficient generation of short
spin-wave packets with duration down to a few nanoseconds. The proposed method
opens a route for the implementation of high-speed magnonic systems for
transmission and processing of information on the nanoscale.


title:
On the relationship between circumstellar disc size and X-ray outbursts
  in Be/X-ray binaries

abstract:
  We present long term H$\alpha$ monitoring results of five Be/X-ray binaries
to study the Be disc size variations and their influence on Type II (giant)
X-ray outbursts. The work is done in the context of the viscous decretion disc
model which predicts that Be discs in binary systems are truncated by resonant
torques induced by the neutron star in its orbit. Our observations show that
type II outbursts are not correlated(nor anti-correlated) with the disc size,
as they are seen to occur both at relatively small and large Be disc radii. We
discuss these observations in context of alternate interpretation of Be disc
behaviour, such as precession, elongation and density effects, and with
cognisance of the limitations of our disc size estimates.


title: A stable version of Terao conjecture

abstract:
  The aim of this note is to introduce a stable version of Terao conjecture,
using the notion of infinitely stably extendability of vector bundles on
$\mathbb P^n$, considered and characterized by I. Coanda in arXiv:0907.4040.


title: The joint distributions of running maximum of a Slepian processes

abstract:
  Consider the Slepian process $S$ defined by $ S(t)=B(t+1)-B(t),t\in [0,1]$
with $B(t),t\in \R$ a standard Brownian motion.In this contribution we analyze
the joint distribution between the maximum $m_{s}=\max_{0\leq u\leq s}S(u)$
certain and the maximum $M_t=\max_{0\leq u\leq t}S(u)$ for $0< s < t$ fixed.
Explicit integral expression are obtained for the distribution function of the
partial maximum $m_{s}$ and the joint distribution function between $m_{s}$ and
$M_t$. We also use our results to determine the moments of $m_{s}$.


title:
Experimental Constructions of Binary Matrices with Good Peak-Sidelobe
  Distances

abstract:
  Skirlo et al., in 'Binary matrices of optimal autocorrelations as alignment
marks' [Journal of Vacuum Science and Technology Series B 33(2) (2015) 1-7],
defined a new class of binary matrices by maximizing the peak-sidelobe
distances in the aperiodic autocorrelations and, by exhaustive computer
searches, found the optimal square matrices of dimension up to 7 x 7, and
optimal diagonally symmetric matrices of dimensions 8 x 8 and 9 x 9. We make an
initial investigation into and propose a strategy for (deterministically)
constructing binary matrices with good peak-sidelobe distances. We construct
several classes of these and compare their distances to those of the optimal
matrices found by Skirlo et al. Our constructions produce matrices that are
near optimal for small dimension. Furthermore, we formulate a tight upper bound
on the peak-sidelobe distance of a cer- tain class of circulant matrices.
Interestingly, binary matrices corresponding to certain difference sets and
almost difference sets have peak-sidelobe distances meeting this upper bound.


title: Toward a history of mathematics focused on procedures

abstract:
  Abraham Robinson's framework for modern infinitesimals was developed half a
century ago. It enables a re-evaluation of the procedures of the pioneers of
mathematical analysis. Their procedures have been often viewed through the lens
of the success of the Weierstrassian foundations. We propose a view without
passing through the lens, by means of proxies for such procedures in the modern
theory of infinitesimals. The real accomplishments of calculus and analysis had
been based primarily on the elaboration of novel techniques for solving
problems rather than a quest for ultimate foundations. It may be hopeless to
interpret historical foundations in terms of a punctiform continuum, but
arguably it is possible to interpret historical techniques and procedures in
terms of modern ones. Our proposed formalisations do not mean that Fermat,
Gregory, Leibniz, Euler, and Cauchy were pre-Robinsonians, but rather indicate
that Robinson's framework is more helpful in understanding their procedures
than a Weierstrassian framework.


title: The wonderful compactification for quantum groups

abstract:
  In this paper, we introduce a quantum version of the wonderful
compactification of a group as a certain noncommutative projective scheme. Our
approach stems from the fact that the wonderful compactification encodes the
asymptotics of matrix coefficients, and from its realization as a GIT quotient
of the Vinberg semigroup. In order to define the wonderful compactification for
a quantum group, we adopt a generalized formalism of $\mathsf{Proj}$ categories
in the spirit of Artin and Zhang. Key to our construction is a quantum version
of the Vinberg semigroup, which we define as a $q$-deformation of a certain
Rees algebra, compatible with a standard Poisson structure. Furthermore, we
discuss quantum analogues of the stratification of the wonderful
compactification by orbits for a certain group action, and provide explicit
computations in the case of $\mathrm{SL}_2$.


title: Majorana zero modes in spintronics devices

abstract:
  We show that topological phases should be realizable in readily available and
well studied heterostructures. In particular we identify a new class of
topological materials which are well known in spintronics: helical
ferromagnet-superconducting junctions. We note that almost all previous work on
topological heterostructures has focused on creating Majorana modes at the
proximity interface in effectively two-dimensional or one-dimensional systems.
The particular heterostructures we address exhibit finite range proximity
effects leading to nodal superconductors with Majorana modes localized well
away from this interface. To show this, we implement a Bogoliubov-de Gennes
(BdG) proximity numerical scheme, which importantly, involves two finite
dimensions in a three dimensional junction. Incorporating this level of
numerical complexity serves to distinguish ours from alternative numerical BdG
approaches which are limited by generally assuming translational invariance or
periodic boundary conditions along multiple directions. With this access to the
edges, we are then able to illustrate in a concrete fashion the wavefunctions
of Majorana zero modes, and, moreover, address finite size effects. In the
process we establish consistency with a simple analytical model.


title:
Femtosecond laser direct-write waveplates based on stress-induced
  birefringence

abstract:
  The use of femtosecond lasers to introduce controlled stress states has
recently been demonstrated in silica glass. We use this technique, in
combination with chemical etching, to generate and control stress-induced
birefringence over a well-defined region of interest, demonstrating
direct-write wave plates with precisely tailored retardance levels. This
tailoring enables the fabrication of laser-written polarization optics that can
be tuned to any wavelength for which silica is transparent and with a clear
aperture free of any laser modifications. Using this approach, we achieve
sufficient retardance to act as a quarter-wave plate. The stress distribution
within the clear aperture is analyzed and modeled, providing a generic template
that can be used as a set of design rules for laser-machined polarization
devices.


title:
Distributed power allocation for D2D communications
  underlaying/overlaying OFDMA cellular networks

abstract:
  The implementation of device-to-device (D2D) underlaying or overlaying
pre-existing cellular networks has received much attention due to the potential
of enhancing the total cell throughput, reducing power consumption and
increasing the instantaneous data rate. In this paper we propose a distributed
power allocation scheme for D2D OFDMA communications and, in particular, we
consider the two operating modes amenable to a distributed implementation:
dedicated and reuse modes. The proposed schemes address the problem of
maximizing the users' sum rate subject to power constraints, which is known to
be nonconvex and, as such, extremely difficult to be solved exactly. We propose
here a fresh approach to this well-known problem, capitalizing on the fact that
the power allocation problem can be modeled as a potential game. Exploiting the
potential games property of converging under better response dynamics, we
propose two fully distributed iterative algorithms, one for each operation mode
considered, where each user updates sequentially and autonomously its power
allocation. Numerical results, computed for several different user scenarios,
show that the proposed methods, which converge to one of the local maxima of
the objective function, exhibit performance close to the maximum achievable
optimum and outperform other schemes presented in the literature.


title:
Channel Estimation and Data Equalization in Frequency-Selective MIMO
  Systems with One-Bit Quantization

abstract:
  This paper addresses channel estimation and data equalization on
frequency-selective 1-bit quantized Multiple Input-Multiple Output (MIMO)
systems. No joint processing or Channel State Information is assumed at the
transmitter, and therefore our findings are also applicable to the uplink of
Multi-User MIMO systems. System models for both Orthogonal Division Frequency
Multiplexing (OFDM) and single-carrier schemes are developed. A Cram\'er-Rao
Lower Bound for the estimation problems is derived. The two nonlinear
algorithms Expectation Maximization (EM) and Generalized Approximate Message
Passing (GAMP) are adapted to the problems, and a linear method based on the
Bussgang theorem is proposed. In the OFDM case, the linear method enables
subcarrier-wise estimation, greatly reducing computational complexity.
Simulations are carried out to compare the algorithms with different settings.
The results turn out to be close to the Cram\'er-Rao bound in the low Signal to
Noise Ratio (SNR) region. The OFDM setting is more suitable for the nonlinear
algorithms, and that the linear methods incur a performance loss with respect
to the nonlinear approaches. In the relevant low and medium SNR regions, the
loss amounts to 2-3 dB and might well be justified in exchange for the reduced
computational effort, especially in Massive MIMO settings.


title: Chiral medium produced by parallel electric and magnetic fields

abstract:
  We compute (pseudo)critical temperature, $T_c$, of chiral symmetry
restoration for quark matter in the background of parallel electric and
magnetic fields. This field configuration leads to the production of a chiral
medium on a time scale $\tau$, characterized by a nonvanishing value of the
chiral density that equilibrates due to microscopic processes in the thermal
bath. We estimate the relaxation time $\tau$ to be about $\approx 0.1-1$ fm/c
around the chiral crossover; then we compute the effect of the fields and of
the chiral medium on~$T_c$. We find $T_c$ to be lowered by the external fields
in the chiral medium.


title: Meson Spectroscopy at COMPASS

abstract:
  The goal of the COMPASS experiment at CERN is to study the structure and
dynamics of hadrons. The two-stage spectrometer used by the experiment has
large acceptance and covers a wide kinematic range for charged as well as
neutral particles and can therefore measure a wide range of reactions. The
spectroscopy of light mesons is performed with negative (mostly $\pi^-$) and
positive ($p$, $\pi^+$) hadron beams with a momentum of 190 GeV/$c$. The
light-meson spectrum is measured in different final states produced in
diffractive dissociation reactions with squared four-momentum transfer $t$ to
the target between 0.1 and 1.0 $(\text{GeV}/c)^2$. The flagship channel is the
$\pi^-\pi^-\pi^+$ final state, for which COMPASS has recorded the currently
world's largest data sample. These data not only allow to measure the
properties of known resonances with high precision, but also to observe new
states. Among these is a new axial-vector signal, the $a_1(1420)$, with unusual
properties. Novel analysis techniques have been developed to extract also the
amplitude of the $\pi^-\pi^+$ subsystem as a function of $3\pi$ mass from the
data. The findings are confirmed by the analysis of the $\pi^-\pi^0\pi^0$ final
state.


title: The basic $dd^{\mathcal{J}}$-lemma

abstract:
  The purpose of this short paper is to further develop the theory of
transverse generalized complex structures. We focus on proving some equivalent
conditions to the basic $dd^{\mathcal{J}}$ -lemma. We justify our approach by
describing the transverse symplectic structure in this language and relating
the basic $dd^{\mathcal{J}}$-lemma to the surjectivity of the Lefschetz map. We
also present a non-trivial example of a foliation endowed with a transverse
generalized complex structure. Transverse generalized complex structures do not
rely heavily on the existence of a bundle-like metric, which makes them a
convienient tool to study some non-Riemmanian foliations.


title: Around operators not increasing the degree of polynomials

abstract:
  We present a generic operator $J$ simply defined as a linear map not
increasing the degree from the vectorial space of polynomial functions into
itself and we address the problem of finding the polynomial sequences that
coincide with the (normalized) $J$-image of themselves. The technique developed
assembles different types of operators and initiates with a transposition of
the problem to the dual space. It is also provided examples where the results
are applied to the case where $J$'s expansion is limited to three terms.


title:
Matrix Product State for Higher-Order Tensor Compression and
  Classification

abstract:
  This paper introduces matrix product state (MPS) decomposition as a new and
systematic method to compress multidimensional data represented by higher-order
tensors. It solves two major bottlenecks in tensor compression: computation and
compression quality. Regardless of tensor order, MPS compresses tensors to
matrices of moderate dimension which can be used for classification. Mainly
based on a successive sequence of singular value decompositions (SVD), MPS is
quite simple to implement and arrives at the global optimal matrix, bypassing
local alternating optimization, which is not only computationally expensive but
cannot yield the global solution. Benchmark results show that MPS can achieve
better classification performance with favorable computation cost compared to
other tensor compression methods.


title:
Decomposition rules for the ring of representations of non-Archimedean
  $GL_n$

abstract:
  Let $\mathcal{R}$ be the Grothendieck ring of complex smooth finite-length
representations of the sequence of p-adic groups $\{GL_n(F)\}_{n=0}^\infty$,
with multiplication defined through parabolic induction. We study the problem
of the decomposition of products of irreducible representations in
$\mathcal{R}$.
  We obtain a necessary condition on irreducible factors of a given product by
introducing a width invariant. Width $1$ representations form the previously
studied class of ladder representations.
  We later focus on the case of a product of two ladder representations, for
which we establish that all irreducible factors appear with multiplicity one.
  Finally, we propose a general rule for the composition series of a product of
two ladder representations and prove its validity for cases in which the
irreducible factors correspond to smooth Schubert varieties.


title: The reconstruction theorem in Besov spaces

abstract:
  The theory of regularity structures sets up an abstract framework of modelled
distributions generalising the usual H\"older functions and allowing one to
give a meaning to several ill-posed stochastic PDEs. A key result in that
theory is the so-called reconstruction theorem: it defines a continuous linear
operator that maps spaces of "modelled distributions" into the usual space of
distributions. In the present paper, we extend the scope of this theorem to
analogues to the whole class of Besov spaces $\mathcal{B}^\gamma_{p,q}$ with
non-integer regularity indices. We then show that these spaces behave very much
like their classical counterparts by obtaining the corresponding embedding
theorems and Schauder-type estimates.


title:
Heat and charge transport measurements to access single-electron quantum
  characteristics

abstract:
  In the framework of the Floquet scattering-matrix theory we discuss how
electrical and heat currents accessible in mesoscopics are related to the state
of excitations injected by a single-electron source into an electron waveguide.
We put forward an interpretation of a single-particle heat current, which
differs essentially from that of an electrical current. We show that the
knowledge of both a time-dependent electrical current and a time-dependent heat
current allows the full reconstruction of a single-electron wave function. In
addition we compare electrical and heat shot noise caused by splitting of a
regular stream of single-electron excitations. If only one stream impinges on a
wave splitter, the heat shot noise is proportional to the well-known expression
of the charge shot noise, reflecting the partitioning of the incoming single
particles. The situation differs when two electronic streams collide at the
wave splitter. The shot noise suppression, due to the Pauli exclusion
principle, is governed by different overlap integrals in the case of charge and
of heat.


title: Antenna-enhanced Optoelectronic Probing of Carbon Nanotubes

abstract:
  We report on the first antenna-enhanced optoelectronic microscopy studies on
nanoscale devices. By coupling the emission and excitation to a scanning
optical antenna, we are able to locally enhance the electroluminescence and
photocurrent along a carbon nanotube device. We show that the emission source
of the electroluminescence can be point-like with a spatial extension below 20
nm. Topographic and antenna-enhanced photocurrent measurements reveal that the
emission takes place at the location of highest local electric field indicating
that the mechanism behind the emission is the radiative decay of excitons
created via impact excitation.


title: Near integrability of kink lattice with higher order interactions

abstract:
  In the paper, we make use of Manton's analytical method to investigate the
force between kink and the anti-kink with large distance in $1+1$ dimensional
field theory. The related potential has infinite order corrections of
exponential pattern, and coefficients for each order are determined. These
coefficients can also be obtained by solving the equation of the fluctuation
around the vacuum. At the lowest order, the kink lattice represents the Toda
lattice. With higher order correction terms, the kink lattice can represent one
kind of the generic Toda lattice. With only two sites, the kink lattice is
classically integrable. If the number of sites of the lattice is larger than
two, the kink lattice is not integrable but a near integrable system. We take
use of the Flaschka's variables to study the Lax pair of the kink lattice.
These Flaschka's variables have interesting algebraic relations and the
non-integrability can be manifested. We also discussed the higher Hamiltonians
for the deformed open Toda lattice, which has a similar result as the ordinary
deformed Toda.


title: Structural Bounds on the Dyadic Effect

abstract:
  In this paper we consider the dyadic effect introduced in complex networks
when nodes are distinguished by a binary characteristic. Under these
circumstances two independent parameters, namely dyadicity and heterophilicity,
are able to measure how much the assigned characteristic affects the network
topology. All possible configurations can be represented in a phase diagram
lying in a two-dimensional space that represents the feasible region of the
dyadic effect, which is bound by two upper bounds on dyadicity and
heterophilicity. Using some network's structural arguments, we are able to
improve such upper bounds and introduce two new lower bounds, providing a
reduction of the feasible region of the dyadic effect as well as constraining
dyadicity and heterophilicity within a specific range. Some computational
experiences show the bounds' effectiveness and their usefulness with regards to
different classes of networks.


title:
X-ray absorption and emission spectroscopy study of Mn and Co valence
  and spin states in TbMn$_{\rm 1-x}$Co$_{\rm x}$O$_3$

abstract:
  The valence and spin state evolution of Mn and Co on TbMn$_{\rm 1-x}$Co$_{\rm
x}$O$_3$ series is precisely determined by means of soft and hard x-ray
absorption spectroscopy (XAS) and K$\beta$ x-ray emission spectroscopy (XES).
Our results show the change from Mn$^{3+}$ to Mn$^{4+}$ both high-spin (HS)
together with the evolution from Co$^{2+}$ HS to Co$^{3+}$ low-spin (LS) with
increasing $\rm x$. In addition, high energy resolution XAS spectra on the K
pre-edge region are interpreted in terms of the strong charge transfer and
hybridization effects along the series. These results correlate well with the
spin values of Mn and Co atoms obtained from the K$\beta$ XES data. From this
study, we determine that Co enters into the transition metal sublattice of
TbMnO$_3$ as a divalent ion in HS state, destabilizing the Mn long range
magnetic order since very low doping compositions (${\rm x} \le 0.1$). Samples
in the intermediate composition range ($0.4 \le {\rm x} \le 0.6$) adopt the
crystal structure of a double perovskite with long range ferromagnetic ordering
which is due to Mn$^{4+}$-O-Co$^{2+}$ superexchange interactions with both
cations in HS configuration. Ferromagnetism vanishes for ${\rm x} \ge 0.7$ due
to the structural disorder that collapses the double perovskite structure. The
spectroscopic techniques reveal the occurrence of Mn$^{4+}$ HS and a
fluctuating valence state Co$^{2+}$ HS/Co$^{3+}$ LS in this composition range.
Disorder and competitive interactions lead to a magnetic glassy behaviour in
these samples.


title:
A Multi-Service Oriented Multiple-Access Scheme For M2M Support in
  Future LTE

abstract:
  We propose a novel multiple-access technique to overcome the shortcomings of
the current proposals for the future releases of Long-Term Evolution (LTE). We
provide a unified radio access system that efficiently and flexibly integrates
both traditional cellular services and machine-to-machine (M2M) connections
arising from Internet-of-Things (IoT) applications. The proposed solution,
referred to as multi-service oriented multiple access (MOMA), is based on a)
establishing separate classes of users using relevant criteria that go beyond
the simple handheld-IoT device split, b) service-dependent hierarchical
spreading of the data signals and c) a mix of multiuser and single-user
detection schemes at the receiver. Signal spreading in MOMA allows to handle
densely connected devices with different quality-of-service (QoS) profiles and
at the same time its flexible receiver structure allows to allocate the
receiver computational resources to the connections that need it most. This
yields a scalable and efficient use of the available radio resources and a
better service integration. While providing significant advantages for key
future communications scenarios, MOMA can be incorporated into LTE with a
limited impact on the protocol structure and the signaling overhead.


title: Theoretical Properties of Entropy in a Strong Coupling Region

abstract:
  Entropy is a quantity for counting physical degrees of freedom in a system.
At a finite temperature, one can use thermal entropy to study thermodynamical
properties. At zero temperature, entanglement entropy is expected to provide a
suitable order parameter of a phase structure. Especially, the entanglement
entropy exhibits an interesting codimension two area law in a strongly coupled
conformal field theory. We compute thermal entropy in a non-relativistic model
with an infinite fermion mass limit from an exact effective potential to obtain
thermal entropy at an infinite strong coupling limit. The computational result
provides vanishing thermal entropy at an infinite strong coupling limit with a
finite lattice spacing. The non-trivial topological term can be included in the
strongly coupled lattice system to obtain the non-trivial entropy and the
topology can be marked from the entropy. We first compute the thermal entropy
in a two dimensional lattice topological quantum field theory to study the
lattice artifact and also argue that a theory possibly has translational
invariance if a system does not have a volume law in the entanglement entropy.
Finally, we show that a coefficient of a universal term of the entanglement
entropy should not be affected by a choice of an entangling surface in two
dimensional conformal field theory for one interval case. We also discuss a
choice of the entangling surface in the entanglement entropy in two dimensional
$\mathrm{CP}^{N-1}$ model at the large $N$ limit.


title:
Ill-posedness for the 3D inhomogeneous Navier-Stokes equations in the
  critical Besov space near $L^6$ framework

abstract:
  We prove the ill-posedness for the 3D incompressible inhomogeneous
Navier-stokes equations in critical Besov space. In particular, a norm
inflation happens in finite time with the initial data satisfying
$$\|a_0\|_{\dot{B}_{p,1}^\frac{3}{p}}+\|u_0\|_{\dot{B}_{6,1}^{-\frac{1}{2}}}\le
\delta,\ p>6$$ or
$$\|a_0\|_{\dot{B}_{6,1}^\frac{1}{2}}+\|u_0\|_{\dot{B}_{p,1}^{\frac{3}{p}-1}}\le
\delta,\ p>6.$$ To obtain the norm inflation, we construct a special class of
initial data and introduce a modified pressure. Comparing with the classical
Navier-Stokes equations in $L^\infty$ framework, we can obtain the
ill-posedness for the inhomogeneous case in near $L^6$ framework.


title: SCTP User Message Interleaving Integration and Validation

abstract:
  The Stream Control Transmission Protocol (SCTP) is a connection and message
oriented transport protocol. It supports multiple uni-directional streams in
each direction allowing user message sequence preservation within each stream.
This minimizes the re-sequencing delay at the receiver side in case of message
loss. The base protocol, although being optimized for small messages, supports
arbitrary large user messages by using fragmentation and reassembly at the cost
of adding delays at the sender side. To overcome this limitation, a protocol
extension called User Message Interleaving is currently being specified by the
Internet Engineering Task Force (IETF). This paper describes the new extension,
its integration and validation in the context of the INET framework.


title: Enabling Soft Vertical Handover for MIPv6 in OMNeT++

abstract:
  Switching connectivity over multiple wireless interfaces of a mobile node is
essential when performing handover between heterogeneous networks. In such a
communication scenario, session continuity as experienced by the user can be
enhanced if soft handover is enabled through the concept of make-before-break.
However, some of the available networking protocols need to be modified to
support this feature. This work gives an insight into the supplementary modules
we implemented and the modification conducted in MIPv6 model of OMNeT++ to
facilitate soft handover and data offloading for mobile nodes.


title: Performance and Security Evaluation of SDN Networks in OMNeT++/INET

abstract:
  Software Defined Networking (SDN) has been recently introduced as a new
communication paradigm in computer networks. By separating the control plane
from the data plane and entrusting packet forwarding to straightforward
switches, SDN makes it possible to deploy and run networks which are more
flexible to manage and easier to configure. This paper describes a set of
extensions for the INET framework, which allow researchers and network
designers to simulate SDN architectures and evaluate their performance and
security at design time. Together with performance evaluation and design
optimization of SDN networks, our extensions enable the simulation of SDN-based
anomaly detection and mitigation techniques, as well as the quantitative
evaluation of cyber-physical attacks and their impact on the network and
application. This work is an ongoing research activity, and we plan to propose
it for an official contribution to the INET framework.


title:
Sub 100-fs, 5.2-$\mu$m ZGP Parametric Amplifier Driven by a ps Ho:YAG
  Chirped Pulse Amplifier and its application to high harmonic generation

abstract:
  We report a 1 kHz repetition-rate mid-IR (MIR) optical parametric amplifier
(OPA) system operating at a central wavelength of 5.2 $\mu$m with the
tail-to-tail spectrum extending over 1.5 $\mu$m and delivering 40 $\mu$J pulses
that are compressed to 99 fs (5.6 optical cycles). Also we develop a novel
pulse compression scheme for further pulse compression and wavelength
tunability. As the first application of this laser system, we generated high
harmonics in bulk ZnSe above the bandgap, dense exciton generation after
10-photon absorption, high order sum- and difference-frequency generation,
ultrafast transition in the conduction band, which reflects the structure of
conduction bands.


title: Resource Selection for Federated Search on the Web

abstract:
  A publicly available dataset for federated search reflecting a real web
environment has long been absent, making it difficult for researchers to test
the validity of their federated search algorithms for the web setting. We
present several experiments and analyses on resource selection on the web using
a recently released test collection containing the results from more than a
hundred real search engines, ranging from large general web search engines such
as Google, Bing and Yahoo to small domain-specific engines. First, we
experiment with estimating the size of uncooperative search engines on the web
using query based sampling and propose a new method using the ClueWeb09
dataset. We find the size estimates to be highly effective in resource
selection. Second, we show that an optimized federated search system based on
smaller web search engines can be an alternative to a system using large web
search engines. Third, we provide an empirical comparison of several popular
resource selection methods and find that these methods are not readily suitable
for resource selection on the web. Challenges include the sparse resource
descriptions and extremely skewed sizes of collections.


title:
Structured Dropout for Weak Label and Multi-Instance Learning and Its
  Application to Score-Informed Source Separation

abstract:
  Many success stories involving deep neural networks are instances of
supervised learning, where available labels power gradient-based learning
methods. Creating such labels, however, can be expensive and thus there is
increasing interest in weak labels which only provide coarse information, with
uncertainty regarding time, location or value. Using such labels often leads to
considerable challenges for the learning process. Current methods for
weak-label training often employ standard supervised approaches that
additionally reassign or prune labels during the learning process. The
information gain, however, is often limited as only the importance of labels
where the network already yields reasonable results is boosted. We propose
treating weak-label training as an unsupervised problem and use the labels to
guide the representation learning to induce structure. To this end, we propose
two autoencoder extensions: class activity penalties and structured dropout. We
demonstrate the capabilities of our approach in the context of score-informed
source separation of music.


title: Statistical Inference in a Directed Network Model with Covariates

abstract:
  Networks are often characterized by node heterogeneity for which nodes
exhibit different degrees of interaction and link homophily for which nodes
sharing common features tend to associate with each other. In this paper, we
propose a new directed network model to capture the former via node-specific
parametrization and the latter by incorporating covariates. In particular, this
model quantifies the extent of heterogeneity in terms of outgoingness and
incomingness of each node by different parameters, thus allowing the number of
heterogeneity parameters to be twice the number of nodes. We study the maximum
likelihood estimation of the model and establish the uniform consistency and
asymptotic normality of the resulting estimators. Numerical studies demonstrate
our theoretical findings and a data analysis confirms the usefulness of our
model.


title: Random motions with space-varying velocities

abstract:
  Random motions on the line and on the plane with space-varying velocities are
considered and analyzed in this paper.
  On the line we investigate symmetric and asymmetric telegraph processes with
space-dependent velocities and we are able to present the explicit distribution
of the position $\mathcal{T}(t)$, $t>0$, of the moving particle.
  Also the case of a non-homogeneous Poisson process (with rate $\lambda =
\lambda(t)$) governing the changes of direction is analyzed in three specific
cases. For the special case $\lambda(t)= \alpha/t$ we obtain a random motion
related to the Euler-Poisson-Darboux (EPD) equation which generalizes the
well-known case treated e.g. in Foong and Van Kolck (1992), Garra and Orsingher
(2016) and Rosencrans (1973).
  A EPD--type fractional equation is also considered and a parabolic solution
(which in dimension $d=1$ has the structure of a probability density) is
obtained.
  Planar random motions with space--varying velocities and infinite directions
are finally analyzed in Section 5. We are able to present their explicit
distributions and for polynomial-type velocity structures we obtain the hyper
and hypo-elliptic form of their support (of which we provide a picture).


title: Schottky groups and maximal representations

abstract:
  We describe a construction of Schottky type subgroups of automorphism groups
of partially cyclically ordered sets. We apply this construction to the Shilov
boundary of a Hermitian symmetric space and show that in this setting Schottky
subgroups correspond to maximal representations of fundamental groups of
surfaces with boundary. As an application, we construct explicit fundamental
domains for the action of maximal representations into
$\mathrm{Sp}(2n,\mathbb{R})$ on $\mathbb{RP}^{2n-1}$.


title:
Towards a deterministic KPZ equation with fractional diffusion: The
  stationary problem

abstract:
  In this work we analyze the existence of solution to the fractional
quasilinear problem, \begin{equation*} \left\{ \begin{array}{rcll} (-\Delta)^s
u &= & |\nabla u|^{p}+ \l f & \text{ in }\Omega , u &=& 0 &\hbox{ in }
\mathbb{R}^N\setminus\Omega, u&>&0 &\hbox{ in }\Omega, \end{array}% \right.
\end{equation*}% where $\Omega \subset \ren$ is a bounded regular domain
($\mathcal{C}^2$ is sufficient), $s\in (\frac 12, 1)$, $1<p$ and $f$ is a
measurable nonnegative function with suitable hypotheses.
  The analysis is done separately in three cases, subcritical, $1<p<2s$,
critical, $p=2s$, and supercritical, $p>2s$.


title:
Direct identification of dilute surface spins on Al$_2$O$_3$: Origin of
  flux noise in quantum circuits

abstract:
  It is universally accepted that noise and decoherence affecting the
performance of superconducting quantum circuits are consistent with the
presence of spurious two-level systems (TLS). In recent years bulk defects have
been generally ruled out as the dominant source, and the search has focused on
surfaces and interfaces. Despite a wide range of theoretical models and
experimental efforts, the origin of these surface TLS still remains largely
unknown, making further mitigation of TLS induced decoherence extremely
challenging. Here we use a recently developed on-chip electron spin resonance
(ESR) technique that allows us to detect spins with a very low surface
coverage. We combine this technique with various surface treatments
specifically to reveal the nature of native surface spins on Al$_2$O$_3$ -- the
mainstay of almost all solid state quantum devices. On a large number of
samples we resolve three ESR peaks with the measured total paramagnetic spin
density $n=2.2\times 10^{17}$m$^{-2}$, which matches the density inferred from
the flux noise in SQUIDs. We show that two of these peaks originate from
physisorbed atomic hydrogen which appears on the surface as a by-product of
water dissociation. We suggest that the third peak is due to molecular oxygen
on the Al$_2$O$_3$ surface captured at strong Lewis base defect sites,
producing charged O$_2^-$. These results provide important information towards
the origin of charge and flux noise in quantum circuits. Our findings open up a
whole new approach to identification and controlled reduction of paramagnetic
sources of noise in solid state quantum devices.


title: Geodesic Witten diagrams with an external spinning field

abstract:
  We explore AdS/CFT correspondence between geodesic Witten diagrams and
conformal blocks (conformal partial waves) with an external symmetric traceless
tensor field. We derive an expression for the conformal partial wave with an
external spin-1 field and show that this expression is equivalent to the
amplitude of the geodesic Witten diagram. We also show the equivalence by using
conformal Casimir equation in embedding formalism. Furthermore, we extend the
construction of the amplitude of the geodesic Witten diagram to an external
arbitrary symmetric traceless tensor field. We show our construction agrees
with the known result of the conformal partial waves.


title:
Single mode waveguide platform for spontaneous and surface-enhanced
  on-chip Raman spectroscopy

abstract:
  We review an on-chip approach for spontaneous Raman spectroscopy and Surface
Enhanced Raman Spectroscopy (SERS) based on evanescent excitation of the
analyte as well as evanescent collection of the Raman signal using
Complementary Metal Oxide Semiconductor (CMOS) compatible single mode
waveguides. The signal is either directly collected from the analyte molecules
or via plasmonic nanoantennas integrated on top of the waveguides. Flexibility
in the design of the geometry of the waveguide, and/or the geometry of the
antennas, enables optimization of the collection efficiency. Furthermore the
sensor can be integrated with additional functionality (sources, detectors,
spectrometers) on the same chip. In this paper, the basic theoretical concepts
are introduced to identify the key design parameters and some proof-of-concept
experimental results are reviewed.


title: Supersymmetry in 6d Dirac Action

abstract:
  We investigate a 6d Dirac fermion on a rectangle. It is found that the 4d
spectrum is governed by $N=2$ supersymmetric quantum mechanics. Then we
demonstrate that the supersymmetry is very useful for classifying all the
allowed boundary conditions and to expand the 6d Dirac field in Kaluza-Klein
modes. A striking feature of the model is that even though the 6d Dirac fermion
has non-vanishing bulk mass, the 4d mass spectrum can contain degenerate
massless chiral fermions, which may provide a hint to solve the problem of the
generation of quarks and leptons. It is pointed out that zero-energy solutions
are not affected by the presence of the boundaries, while the boundary
conditions work well for determining the positive-energy solutions. We also
provide a brief discussion on possible boundary conditions in the general case,
especially those on polygons.


title:
Reducing individuals' risk sensitiveness can promote positive and
  non-alarmist views about catastrophic events in an agent-based simulation

abstract:
  We present a cognitive model of opinion dynamics which studies the behavior
of a population of interacting individuals in the context of risk of natural
disaster. In particular, we investigate the response of the individuals to the
information received by institutional sources about the correct behaviors for
prevention and harm reduction. The results of our study show that alarmist
opinions are more likely to be adopted by populations, since worried people


title: A parallel pattern for iterative stencil + reduce

abstract:
  We advocate the Loop-of-stencil-reduce pattern as a means of simplifying the
implementation of data-parallel programs on heterogeneous multi-core platforms.
Loop-of-stencil-reduce is general enough to subsume map, reduce, map-reduce,
stencil, stencil-reduce, and, crucially, their usage in a loop in both
data-parallel and streaming applications, or a combination of both. The pattern
makes it possible to deploy a single stencil computation kernel on different
GPUs. We discuss the implementation of Loop-of-stencil-reduce in FastFlow, a
framework for the implementation of applications based on the parallel
patterns. Experiments are presented to illustrate the use of
Loop-of-stencil-reduce in developing data-parallel kernels running on
heterogeneous systems.


title:
Regenerative Soot-IV: The state of the carbon vapour in the regenerative
  sooting discharge

abstract:
  Formation of the regenerative soot is the process of recycling and
introduction of the cathode deposited carbon clusters into the discharge. The
agglomerates of carbon clusters on the cathode release their constituents into
the plasma that goes from the pure sputtering mode to the sooting one. The
process of the regeneration of the soot that emits large carbon clusters is
discussed by evaluating the state of the carbon vapour by using the
characteristic line emissions from the discharge.


title: FPGA Implementation of a Novel Image Steganography for Hiding Images

abstract:
  As the complexity of current data flow systems and according infrastructure
networks increases, the security of data transition through such platforms
becomes more important. Thus, different areas of steganography turn to one of
the most challengeable topics of current researches. In this paper a novel
method is presented to hide an image into the host image and Hardware/Software
design is proposed to implement our stagenography system on FPGA- DE2 70 Altera
board. The size of the secret image is quadrant of the host image. Host image
works as a cipher key to completely distort and encrypt the secret image using
XOR operand. Each pixel of the secret image is composed of 8 bits (4 bit-pair)
in which each bit-pair is distorted by XORing it with two LSB bits of the host
image and putting the results in the location of two LSB bits of host image.
The experimental results show the effectiveness of the proposed method compared
to the most recently proposed algorithms by considering that the obtained
information entropy for encrypt image is approximately equal to 8.


title: MESON2016 -- Concluding Remarks

abstract:
  Several topics presented and discussed at MESON2016 are highlighted,
including pentaquarks, dibaryons and meson-nuclear bound states.


title: Discrete Uniqueness Sets for Functions with Spectral Gaps

abstract:
  It is well-known that entire functions whose spectrum belongs to a fixed
bounded set $S$ admit real uniformly discrete uniqueness sets $\Lambda$. We
show that the same is true for much wider spaces of continuous functions. In
particular, Sobolev spaces have this property whenever $S$ is a set of infinite
measure having "periodic gaps". The periodicity condition is crucial. For sets
$S$ with randomly distributed gaps, we show that the uniformly discrete sets
$\Lambda$ satisfy a strong non-uniqueness property: Every discrete function
$c(\lambda)\in l^2(\Lambda)$ can be interpolated by an analytic $L^2$-function
with spectrum in $S$.


title:
Search for dark matter in association with a Higgs boson decaying to
  $b$-quarks in $pp$ collisions at $\sqrt{s} = 13$ TeV with the ATLAS detector

abstract:
  A search for dark matter pair production in association with a Higgs boson
decaying to a pair of bottom quarks is presented, using 3.2 $fb^{-1}$ of $pp$
collisions at a centre-of-mass energy of 13 TeV collected by the ATLAS detector
at the LHC. The decay of the Higgs boson is reconstructed as a high-momentum
$b\bar{b}$ system with either a pair of small-radius jets, or a single
large-radius jet with substructure. The observed data are found to be
consistent with the expected backgrounds. Results are interpreted using a
simplified model with a $Z'$ gauge boson mediating the interaction between dark
matter and the Standard Model as well as a two-Higgs-doublet model containing
an additional $Z'$ boson which decays to a Standard Model Higgs boson and a new
pseudoscalar Higgs boson, the latter decaying into a pair of dark matter
particles.


title:
Generalized twisted cubics on a cubic fourfold as a moduli space of
  stable objects

abstract:
  We revisit the work of Lehn-Lehn-Sorger-van Straten on twisted cubic curves
in a cubic fourfold not containing a plane in terms of moduli spaces. We show
that the blow-up $Z'$ along the cubic of the irreducible holomorphic symplectic
eightfold $Z$, described by the four authors, is isomorphic to an irreducible
component of a moduli space of Gieseker stable torsion sheaves or rank three
torsion free sheaves. For a very general such cubic fourfold, we show that $Z$
is isomorphic to a connected component of a moduli space of tilt-stable objects
in the derived category and to a moduli space of Bridgeland stable objects in
the Kuznetsov component. Moreover, the contraction between $Z'$ and $Z$ is
realized as a wall-crossing in tilt-stability. Finally, $Z$ is birational to an
irreducible component of Gieseker stable aCM bundles of rank six.


title:
Reentrant phenomenon and inverse magnetocaloric effect in a generalized
  spin-(1/2,s) Fisher's super-exchange antiferromagnet

abstract:
  The thermodynamic and magnetocaloric properties of a generalized
spin-$(1/2,s)$ Fisher's super-exchange antiferromagnet are exactly investigated
by using the decoration-iteration mapping transformation. Besides the critical
temperature, sublattice magnetization, total magnetization, entropy and
specific heat, the isothermal entropy change and adiabatic temperature change
are rigorously calculated in order to examine cooling efficiency of the model
in a vicinity of the first- and second-order phase transitions. It is shown
that an enhanced inverse magnetocaloric effect occurs around the temperature
interval $T_c(B\neq 0) \lesssim T < T_c(B = 0)$ for any magnetic-field change
$\Delta B: 0 \to B$. The most pronounced inverse magnetocaloric effect can be
found nearby the critical field, which corresponds to the zero-temperature
phase transition from the long-range ordered ground state to the paramagnetic
one. The observed phenomenon increases with the increasing value of decorating
spins. Furthermore, sufficiently high values of decorating spins have also
linked to a possibility of observing reentrant phase transitions at finite
temperatures.


title:
Model prediction for temperature dependence of meson pole masses from
  lattice QCD results on meson screening masses

abstract:
  We propose a practical effective model by introducing temperature ($T$)
dependence to the coupling strengths of four-quark and six-quark
Kobayashi-Maskawa-'t Hooft interactions in the 2+1 flavor Polyakov-loop
extended Nambu-Jona-Lasinio model. The $T$ dependence is determined from LQCD
data on the renormalized chiral condensate around the pseudocritical
temperature $T_c^{\chi}$ of chiral crossover and the screening-mass difference
between $\pi$ and $a_0$ mesons in $T > 1.1T_c^\chi$ where only the $U(1)_{\rm
A}$-symmetry breaking survives. The model well reproduces LQCD data on
screening masses $M_{\xi}^{\rm scr}(T)$ for both scalar and pseudoscalar
mesons, particularly in $T \ge T_c^{\chi}$. Using this effective model, we
predict meson pole masses $M_{\xi}^{\rm pole}(T)$ for scalar and pseudoscalar
mesons. For $\eta'$ meson, the prediction is consistent with the experimental
value at finite $T$ measured in heavy-ion collisions. We point out that the
relation $M_{\xi}^{\rm scr}(T)-M_{\xi}^{\rm pole}(T) \approx M_{\xi'}^{\rm
scr}(T)-M_{\xi'}^{\rm pole}(T)$ is pretty good when $\xi$ and $\xi'$ are scalar
mesons, and show that the relation $M_{\xi}^{\rm scr}(T)/M_{\xi'}^{\rm scr}(T)
\approx M_{\xi}^{\rm pole}(T)/M_{\xi'}^{\rm pole}(T)$ is well satisfied within
20% error when $\xi$ and $\xi'$ are pseudoscalar mesons and also when $\xi$ and
$\xi'$ are scalar mesons.


title: Anomalous spectral lines and relic quantum nonequilibrium

abstract:
  We describe features that could be observed in the line spectra of relic
cosmological particles should quantum nonequilibrium be preserved in their
statistics. According to our arguments, these features would represent a
significant departure from those of a conventional origin. Among other
features, we find a possible spectral broadening that is proportional to the
energy resolution of the recording telescope (and so could be much larger than
any conventional broadening). Notably, for a range of possible initial
conditions we find the possibility of spectral line "narrowing", whereby a
telescope could observe a line that is narrower than it is conventionally able
to resolve. We discuss implications for the indirect search for dark matter,
with particular reference to some recent controversial spectral lines.


title:
Motion of charged particle in Reissner-Nordstrom spacetime: A Jacobi
  metric approach

abstract:
  The present work discusses motion of neutral and charged particles in
Reissner - Nordstrom spacetime. The constant energy paths are derived in a
variational principle framework using the Jacobi metric which is parameterized
by conserved particle energy. Of particular interest is the case of particle
charge and Reissner-Nordstrom black hole charge being of same sign since this
leads to a clash of opposing forces - gravitational (attractive) and Coulomb
(repulsive). Our paper aims to compliment the recent works of Pugliese, Quevedo
and Ruffini [1,2]. The energy dependent Gaussian curvature (induced by Jacobi
metric), plays an important role in classifying the trajectories.


title: MSTD sets and Freiman isomorphisms

abstract:
  An MSTD set is a finite set with more pairwise sums than differences.
$(\Upsilon,\Phi)$-ismorphisms are generalizations of Freiman isomorphisms to
arbitrary linear forms. These generalized isomorphisms are used to prove that
every finite set of real numbers is Freiman isomorphic to a finite set of
integers. This implies that there exists no MSTD set $A$ of real numbers with
$|A| \leq 7$, and, up to Freiman isomorphism, there exists exactly one MSTD set
$A$ of real numbers with $|A| = 8$.


title: On a conjecture involving Laplacian eigenvalues of trees

abstract:
  Motivated by classic tree algorithms, in 1995 we designed a bottom-up $O(n)$
algorithm to compute the determinant of a tree's adjacency matrix $A$. In 2010
an $O(n)$ algorithm was found for constructing a diagonal matrix congruent to
$A + xI_n$, $x \in \mathbb{R}$, enabling one to easily count the number of
eigenvalues in any interval. A variation of the algorithm allows Laplacian
eigenvalues in trees to be counted. We conjecture that for any tree $T$ of
order $n \geq 2$, at least half of its Laplacian eigenvalues are less than
$\bar{d} = 2 - \frac{2}{n}$, its average vertex degree.


title:
Stable clustering and the resolution of dissipationless cosmological
  N-body simulations

abstract:
  The determination of the resolution of cosmological N-body simulations, i.e.,
the range of scales in which quantities measured in them represent accurately
the continuum limit, is an important open question. We address it here using
scale-free models, for which self-similarity provides a powerful tool to
control resolution. Such models also provide a robust testing ground for the
so-called stable clustering approximation, which gives simple predictions for
them. Studying large N-body simulations of such models with different force
smoothing, we find that these two issues are in fact very closely related: our
conclusion is that the accuracy of two point statistics in the non-linear
regime starts to degrade strongly around the scale at which their behaviour
deviates from that predicted by the stable clustering hypothesis. Physically
the association of the two scales is in fact simple to understand: stable
clustering fails to be a good approximation when there are strong interactions
of structures (in particular merging) and it is precisely such non-linear
processes which are sensitive to fluctuations at the smaller scales affected by
discretisation. Resolution may be further degraded if the short distance
gravitational smoothing scale is larger than the scale to which stable
clustering can propagate. We examine in detail the very different conclusions
of studies by Smith et al. (2003) and Widrow et al. (2009} and find that the
strong deviations from stable clustering reported by these works are the
results of over-optimistic assumptions about scales resolved accurately by the
measured power spectra, and the reliance on Fourier space analysis. We
emphasise the much poorer resolution obtained with the power spectrum compared
to the two point correlation function..


title: Unique ergodicity of asynchronous rotations, and application

abstract:
  The main result of this paper is an analogue for a continuous family of tori
of Kronecker-Weyl's unique ergodicity of irrational rotations. We show that the
notion corresponding in this setup to irrationality, namely asynchronicity, is
satisfied in some homogeneous dynamical systems. This is used to prove the
ergodicity of naturals lifts of invariant measures.


title: Perpetual points and periodic perpetual loci in maps

abstract:
  We introduce the concepts of perpetual points and periodic perpetual loci in
discrete--time systems (maps). The occurrence and analysis of these points/loci
are shown and basic examples are considered. We discuss the potential usage and
properties of introduced concepts. The comparison of perpetual points and loci
in discrete--time and continuous--time systems is presented. Discussed methods
can be widely applied in other dynamical systems.


title: Time-dependent injection as a model for rapid blazar flares

abstract:
  Time-dependent injection can cause non-linear cooling effects, which lead to
a faster energy loss of the electrons in jets. The most obvious result is the
appearance of unique breaks in the SED, which would normally be attributed to a
complicated electron distribution. The knowledge of the observation time and
duration is important to interpret the observed spectra, because of the
non-trivial evolution of the SED. Intrinsic gamma-gamma absorption processes in
the emission region are only of minor importance.


title: Symmetries of linearized gravity from adjoint operators

abstract:
  Based on operator identities and their formal adjoints, we derive two
symmetry operators for the linearized Einstein operator on vacuum backgrounds
of Petrov type D and in particular the Kerr spacetime. One of them is of
differential order four and coincides with a result of Cohen and Kegeles. The
other one is a new operator of differential order six. The corresponding
operator identities are based on the Teukolsky equation and the
Teukolsky-Starobinski identities, respectively. The method applies to other
field equations as well, which is illustrated with the Maxwell equation. The
resulting symmetry operators are connected to Hertz and Debye potentials as
well as to the separability of the Teukolsky equation for both Maxwell and
linearized gravity.


title: On Memory Footprints of Partitioned Sparse Matrices

abstract:
  Runtime characteristics of sparse matrix computations and related processes
may be often improved by reducing memory footprints of involved matrices. Such
a reduction can be usually achieved when matrices are processed in a block-wise
manner. The presented study analysed memory footprints of 563 representative
benchmark sparse matrices with respect to their partitioning into
uniformly-sized blocks. Different block sizes and different ways of storing
blocks in memory were considered and statistically evaluated. Memory footprints
of partitioned matrices were additionally compared with lower bounds and with
the CSR storage format. The average measured memory savings against CSR in case
of single and double precision were 42.3 and 28.7 percents, the corresponding
worst-case savings 25.5 and 17.1 percents. Moreover, memory footprints of
partitioned matrices were in average 5 times closer to their lower bounds than
CSR. Based on the obtained results, generic suggestions for efficient
partitioning and storage of sparse matrices in a computer memory are provided.


title:
On the Equivalency of Reliability and Security Metrics for Wireline
  Networks

abstract:
  In this paper, we show the equivalency of weak and strong secrecy conditions
for a large class of secure network coding problems. When we restrict to linear
operations, we show the equivalency of "perfect secrecy and zero-error
constraints" with "weak secrecy and $\epsilon$-error constraints".


title:
Inverse Problems of a Fractional Differential Equation with Bessel
  Operator

abstract:
  Inverse initial and inverse source problems of a time-fractional differential
equation with Bessel operator are considered. Results on existence and
uniqueness of solutions to these problems are presented. The solution method is
based on series expansions using a set of Bessel functions of order zero.
Convergence of the obtained series solutions is also discussed


title: An analogue of Khintchine's theorem for self-conformal sets

abstract:
  Khintchine's theorem is a classical result from metric number theory which
relates the Lebesgue measure of certain limsup sets with the
convergence/divergence of naturally occurring volume sums. In this paper we ask
whether an analogous result holds for iterated function systems (IFSs). We say
that an IFS is approximation regular if we observe Khintchine type behaviour,
i.e., if the size of certain limsup sets defined using the IFS is determined by
the convergence/divergence of naturally occurring sums. We prove that an IFS is
approximation regular if it consists of conformal mappings and satisfies the
open set condition. The divergence condition we introduce incorporates the
inhomogeneity present within the IFS. We demonstrate via an example that such
an approach is essential. We also formulate an analogue of the Duffin-Schaeffer
conjecture and show that it holds for a set of full Hausdorff dimension.
  Combining our results with the mass transference principle of Beresnevich and
Velani \cite{BerVel}, we prove a general result that implies the existence of
exceptional points within the attractor of our IFS. These points are
exceptional in the sense that they are "very well approximated". As a corollary
of this result, we obtain a general solution to a problem of Mahler, and prove
that there are badly approximable numbers that are very well approximated by
quadratic irrationals.
  The ideas put forward in this paper are introduced in the general setting of
IFSs that may contain overlaps. We believe that by viewing IFS's from the
perspective of metric number theory, one can gain a greater insight into the
extent to which they overlap. The results of this paper should be interpreted
as a first step in this investigation.


title:
Stability of multi-solitons for the derivative nonlinear Schr{\"o}dinger
  equation

abstract:
  The nonlinear Schr{\"o}dinger equation with derivative cubic nonlinearity
admits a family of solitons, which are orbitally stable in the energy space. In
this work, we prove the orbital stability of multi-solitons configurations in
the energy space, under suitable assumptions on the speeds and frequencies of
the composing solitons. The main ingredients of the proof are modulation
theory, energy coercivity and monotonicity properties.


title:
Higgs boson couplings in multi-doublet models with natural flavour
  conservation

abstract:
  We investigate the deviation in the couplings of the standard model (SM) like
Higgs boson ($h$) with a mass of 125 GeV from the prediction of the SM in
multi-doublet models within the framework where flavour changing neutral
currents at the tree level are naturally forbidden. After we present the
general expressions for the modified gauge and Yukawa couplings for $h$, we
show the correlation between the deviation in the Yukawa coupling for the tau
lepton $h\tau^+\tau^-$ and that for the bottom quark $hb\bar{b}$ under the
assumption of a non-zero deviation in the $hVV$ $(V=W,Z)$ couplings in two
Higgs doublet models (2HDMs) and three Higgs doublet models (3HDMs) as simple
examples. We clarify the possible allowed prediction of the deviations in the
3HDMs which cannot be explained in the 2HDMs even taking into account the
one-loop electroweak corrections to the Yukawa coupling.


title: Hyperfine-controlled domain-wall motion observed in real space and time

abstract:
  We perform real-space imaging of propagating magnetic domains in the
fractional quantum Hall system using spin-sensitive photoluminescence
microscopy. The propagation is continuous and proceeds in the direction of the
conventional current, i.e. opposite to the electron flow direction. The
mechanism of motion is shown to be connected to polarized nuclear spins around
the domain walls. The propagation velocity increases when nuclei are
depolarized, and decreases when the source-drain current generating this
nuclear polarization is increased. We discuss how these phenomena may arise
from spin interactions along the domain walls.


title: Stronger Reflection from Black Hole Accretion Disks in Soft X-ray States

abstract:
  We analyze 15,000 spectra of 29 stellar-mass black hole candidates collected
over the 16-year mission lifetime of RXTE using a simple phenomenological
model. As these black holes vary widely in luminosity and progress through a
sequence of spectral states, which we broadly refer to as hard and soft, we
focus on two spectral components: The Compton power law and the reflection
spectrum it generates by illuminating the accretion disk. Our proxy for the
strength of reflection is the equivalent width of the Fe-K line as measured
with respect to the power law. A key distinction of our work is that for all
states we estimate the continuum under the line by excluding the thermal disk
component and using only the component that is responsible for fluorescing the
Fe-K line, namely the Compton power law. We find that reflection is several
times more pronounced (~3) in soft compared to hard spectral states. This is
most readily caused by the dilution of the Fe line amplitude from Compton
scattering in the corona, which has a higher optical depth in hard states.
Alternatively, this could be explained by a more compact corona in soft
(compared to hard) states, which would result in a higher reflection fraction.


title:
Minimum Eccentricity Shortest Path Problem: an Approximation Algorithm
  and Relation with the k-Laminarity Problem

abstract:
  The Minimum Eccentricity Shortest Path (MESP) Problem consists in determining
a shortest path (a path whose length is the distance between its extremities)
of minimum eccentricity in a graph. It was introduced by Dragan and Leitert [9]
who described a linear-time algorithm which is an 8-approximation of the
problem. In this paper, we study deeper the double-BFS procedure used in that
algorithm and extend it to obtain a linear-time 3-approximation algorithm. We
moreover study the link between the MESP problem and the notion of laminarity,
introduced by V{\"o}lkel et al [12], corresponding to its restriction to a
diameter (i.e. a shortest path of maximum length), and show tight bounds
between MESP and laminarity parameters.


title: Discrete Dirac-K\"ahler equation and its formulation in algebraic form

abstract:
  A relationship between the discrete Dirac-K\"ahler equation and discrete
analogues of some Dirac type equations in the geometric spacetime algebra is
discussed. We show that a solution of the discrete Dirac-K\"ahler equation can
be represented as the sum and difference of solutions of discrete Dirac type
equations with the corresponding sign of the mass term.


title:
L0 regularisation for the estimation of piecewise constant hazard rates
  in survival analysis

abstract:
  In a survival analysis context we suggest a new method to estimate the
piecewise constant hazard rate model. The method provides an automatic
procedure to find the number and location of cut points and to estimate the
hazard on each cut interval. Estimation is performed through a penalized
likelihood using an adaptive ridge procedure. A bootstrap procedure is proposed
in order to derive valid statistical inference taking both into account the
variability of the estimate and the variability in the choice of the cut
points. The new method is applied both to simulated data and to the Mayo Clinic
trial on primary biliary cirrhosis. The algorithm implementation is seen to
work well and to be of practical relevance.


title:
On unbounded solutions of ergodic problems in r^m for viscous
  hamilton-jacobi equations

abstract:
  In this article we study ergodic problems in the whole space R m for viscous
Hamilton-Jacobi Equations in the case of locally Lips-chitz continuous and
coercive right-hand sides. We prove in particular the existence of a critical
value $\lambda$ * for which (i) the ergodic problem has solutions for all
$\lambda$ $\le$ $\lambda$ * , (ii) bounded from below solutions exist and are
associated to $\lambda$ * , (iii) such solutions are unique (up to an additive
constant). We obtain these properties without additional assumptions in the
superquadratic case, while, in the subquadratic one, we assume the right-hand
side to behave like a power. These results are slight generalizations of
analogous results by N. Ichihara but they are proved in the present paper by
partial differential equations methods, contrarily to N. Ichihara who is using
a combination of pde technics with probabilistic arguments.