title: A Compression-Complexity Measure of Integrated Information

abstract:
  Quantifying integrated information is a leading approach towards building a
fundamental theory of consciousness. Integrated Information Theory (IIT) has
gained attention in this regard due to its theoretically strong framework.
However, it faces some limitations such as current state dependence,
computationally expensive and inability to be applied to real brain data. On
the other hand, Perturbational Complexity Index (PCI) is a clinical measure for
distinguishing different levels of consciousness. Though PCI claims to capture
the functional differentiation and integration in brain networks (similar to
IIT), its link to integrated information theories is rather weak. Inspired by
these two approaches, we propose a new measure - $\Phi^C$ using a novel
compression-complexity perspective that serves as a bridge between the two, for
the first time. $\Phi^C$ is founded on the principles of lossless data
compression based complexity measures which characterize the dynamical
complexity of brain networks. $\Phi^{C}$ exhibits following salient
innovations: (i) mathematically well bounded, (ii) negligible current state
dependence unlike $\Phi$, (iii) integrated information measured as
compression-complexity rather than as an infotheoretic quantity, and (iv)
faster to compute since number of atomic bipartitions scales linearly with the
number of nodes of the network, thus avoiding combinatorial explosion. Our
computer simulations show that $\Phi^C$ has similar hierarchy to $<\Phi>$ for
several multiple-node networks and it demonstrates a rich interplay between
differentiation, integration and entropy of the nodes of a network. $\Phi^C$ is
a promising heuristic measure to characterize the quantity of integrated
information (and hence a measure of quantity of consciousness) in larger
networks like human brain and provides an opportunity to test the predictions
of brain complexity on real neural data.


title:
Poincar\'e, Scale and Conformal Symmetries: Gauge Perspective and
  Cosmological Ramifications

abstract:
  In the first part of the thesis we focus on local symmetries. We review a
self-consistent framework that we employed in order to discuss the dynamics of
the theories of interest. Its merit lies in that we can make the symmetry group
act internally and thus be effectively separated from coordinate
transformations. We investigate under which conditions it is not needed to
introduce extra compensating fields to make relativistic as well as
nonrelativistic theories invariant under local symmetries and more precisely
under scale transformations. We clarify the role that torsion plays in this
context. We highlight the difference between Weyl and conformal invariance and
we demonstrate that not all conformal theories can be coupled to gravity in a
Weyl invariant way. Once this minimalistic treatment for gauging symmetries is
left aside, new possibilities appear. Namely, if we consider the Poincar\'e
group, the presence of the extra modes leads to nontrivial particle dynamics.
We derive constraints such that the theory is free from pathologies. In the
second part we make clear that even when not gauged, the presence of scale
invariance is appealing. First, it makes possible for the dimensionful
parameters that appear in a theory to be generated dynamically and be sourced
by the vacuum expectation value of the dilaton. If the Standard Model is
embedded into a scale-invariant framework, a number of interesting implications
for cosmology arise. The inflationary stage of our Universe and its present-day
acceleration become linked, a connection that might give us insight into the
dark energy dynamics. We show that in the context of gravitational theories
which are invariant under restricted coordinate transformations, the dilaton
instead of being introduced ad hoc, can emerge from the gravitational part of a
theory. We discuss the consequences of the nontrivial way this field emerges in
the action.


title: The cosmological origins of nonlinear Electrodynamics

abstract:
  We present a mechanism that allows to describe any nonlinear theory of
Electrodynamics as a consequence of the coupling of the electromagnetic field
to gravity in the presence of a vacuum represented by the cosmological
constant. We emphasize gravity\rq s exclusive role of catalysis.


title: Dark matter search in the inner galactic center halo with H.E.S.S

abstract:
  The presence of dark matter in the universe is nowadays supported by a
substantial set of astronomical and cosmological observations. A large amount
of dark matter is expected in the Galactic Center (GC) region. Thanks also to
its proximity, it is one of the best targets to look for dark matter particle
self-annihilation into very high energy gamma-rays. We perform a search for
annihilating dark matter in the central 300 parsecs around the GC with the
H.E.S.S. array of ground-based Cherenkov telescopes. Using the full H.E.S.S.- I
dataset (2004-2014) of GC observations, new constraints are derived on the
velocity-weighted annihilation cross section $\langle \sigma v \rangle$ with a
2D likelihood method using spectral and spatial morphologies of the DM signal
compared to background. These constraints are the strongest obtained so far in
the TeV mass range and improve the previous constraints by a factor of 5.
Considering an Einasto profile, the constraints reach $\langle \sigma v
\rangle$ values of $6\times 10^{-26}$cm$^{3}$s$^{-1}$ for a DM particle mass of
1.5 TeV annihilation into W$^+$W$^-$ pairs. In the $\tau^+\tau^-$ channel, the
constraints probe the natural scale for thermal relic cross section for DM
particles of masses between 400 GeV and 2 TeV.


title:
Improving the Correlation Lower Bound for Simultaneous Orthogonal
  Matching Pursuit

abstract:
  The simultaneous orthogonal matching pursuit (SOMP) algorithm aims to find
the joint support of a set of sparse signals acquired under a multiple
measurement vector model. Critically, the analysis of SOMP depends on the
maximal inner product of any atom of a suitable dictionary and the current
signal residual, which is formed by the subtraction of previously selected
atoms. This inner product, or correlation, is a key metric to determine the
best atom to pick at each iteration. This paper provides, for each iteration of
SOMP, a novel lower bound of the aforementioned metric for the atoms belonging
to the correct and common joint support of the multiple signals. Although the
bound is obtained for the noiseless case, its main purpose is to intervene in
noisy analyses of SOMP. Finally, it is shown for specific signal patterns that
the proposed bound outperforms state-of-the-art results for SOMP, and
orthogonal matching pursuit (OMP) as a special case.


title: The 2-Hilbert Space of a Prequantum Bundle Gerbe

abstract:
  We construct a prequantum 2-Hilbert space for any line bundle gerbe whose
Dixmier-Douady class is torsion. Analogously to usual prequantisation, this
2-Hilbert space has the category of sections of the line bundle gerbe as its
underlying 2-vector space. These sections are obtained as certain morphism
categories in Waldorf's version of the 2-category of line bundle gerbes. We
show that these morphism categories carry a monoidal structure under which they
are semisimple and abelian. We introduce a dual functor on the sections, which
yields a closed structure on the morphisms between bundle gerbes and turns the
category of sections into a 2-Hilbert space. We discuss how these 2-Hilbert
spaces fit various expectations from higher prequantisation. We then extend the
transgression functor to the full 2-category of bundle gerbes and demonstrate
its compatibility with the additional structures introduced. We discuss various
aspects of Kostant-Souriau prequantisation in this setting, including its
dimensional reduction to ordinary prequantisation.

categories: math-ph hep-th math.CT math.DG math.MP math.SG


title: Matrix Energy as a Measure of Topological Complexity of a Graph

abstract:
  The complexity of highly interconnected systems is rooted in the interwoven
architecture defined by its connectivity structure. In this paper, we develop
matrix energy of the underlying connectivity structure as a measure of
topological complexity and highlight interpretations about certain global
features of underlying system connectivity patterns. The proposed complexity
metric is shown to satisfy the Weyuker criteria as a measure of its validity as
a formal complexity metric. We also introduce the notion of P point in the
graph density space. The P point acts as a boundary between multiple
connectivity regimes for finite-size graphs.


title: On Neumann and Poincare problems in mathematical physics

abstract:
  It is proved the existence of nonclassical solutions of the Neumann and
Poincare problems for generalizations of the Laplace equation in anisotropic
and nonhomogeneous media in almost smooth domains with arbitrary boundary data
that are measureable with respect to logarithmic capacity. Moreover, it is
shown that the spaces of such solutions have the infinite dimension.


title: Exotic Higgs Decay $h\rightarrow\phi\phi\rightarrow 4b$ at the LHeC

abstract:
  We study the exotic decay of the 125 GeV Higgs boson ($h$) into a pair of
light spin-0 particles ($\phi$) which subsequently decays and results in a $4b$
final state. This decay mode is well motivated in the Next to Minimal
Supersymmetric Standard Model (NMSSM) and extended Higgs sector models. Instead
of searching at the Large Hadron Collider (LHC) and the High Luminosity Large
Hadron Collider (HL-LHC) which are beset by large Standard Model (SM)
backgrounds, we investigate this decay channel at the much cleaner Large Hadron
Electron Collider (LHeC). With some simple selection cuts this channel becomes
nearly free of background at this $ep$ machine, in stark contrast with the
situation at the (HL-)LHC. With a parton level analysis we show that for the
$\phi$ mass range $[20,60]GeV$, with $100\,fb^{-1}$ luminosity the LHeC is
generally capable of constraining
$C_{4b}^2\equiv\kappa_{V}^2\times\text{Br}(h\rightarrow\phi\phi)\times\text{Br}^2(\phi\rightarrow
b\bar{b})$ ($\kappa_{V}$ denotes the $hVV(V=W,Z)$ coupling strength relative to
the SM value) to a few percent level ($95\%$ CLs). With $1\,ab^{-1}$ luminosity
$C_{4b}^2$ at a few per mille level can be probed. These sensitivities are much
better than the HL-LHC performance and demonstrate the important role expected
to be played by the LHeC in probing exotic Higgs decay processes, in addition
to the already proposed invisible Higgs decay channel.


title:
Construction of Zero Cross Correlation Code using a type of Pascal's
  Triangle Matrix for Spectral Amplitude Coding Optical Code Division Multiple
  Access networks

abstract:
  In this paper a new method to construct zero cross correlation code with the
help of Pascal's triangle pattern called Pascal's Triangle Matrix Code (PTMC)
for Spectral Amplitude Coding Optical Code Division Multiple Access (SAC-OCDMA)
system is successfully developed. The advantages of this code are simplicity of
code construction, flexibility of choosing code weight and number of users. The
numerical comparison shows that the newly constructed code is better in code
length than the existing codes such as Optical Orthogonal Code (OOC), Hadamard,
Modified Frequency Hopping (MFH) and Modified Double Weight (MDW) codes and it
supports more users than other Optical Spectrum Code Division Multiple Access
(OSCDMA) codes.


title: Coherence breaking channels and coherence sudden death

abstract:
  Quantum noise is ubiquitous to quantum systems as they incessantly interact
with their surroundings and results in degrading useful resources such as
coherence for single quantum systems and quantum correlations for multipartite
systems. Given the importance of these resources in various quantum information
processing protocols, it is of utmost importance to characterize how
deteriorating is a particular noise scenario (quantum channel) in reference to
a certain resource? Here we develop a theory of coherence breaking channels for
single quantum systems. Any quantum channel on a single quantum system will be
called a coherence breaking channel if it is an incoherent channel and maps any
state to an incoherent state. We explicitly and exhaustively characterize these
coherence breaking channels. Moreover, we define the coherence breaking indices
for incoherent quantum channels and present various examples to elucidate this
concept. We further introduce the concept of coherence sudden death under noisy
evolutions and make an explicit connection of the phenomenon of coherence
sudden death with the coherence breaking channels and the coherence breaking
indices together with various suggestive examples. Furthermore, for higher
dimensional Hilbert spaces, we establish the typicality of the dynamics of
coherence under any incoherent quantum channel exploiting the concentration of
measure phenomenon.


title: Better stability with measurement errors

abstract:
  Often it is desirable to stabilize a system around an optimal state. This can
be effectively accomplished using feedback control, where the system deviation
from the desired state is measured in order to determine the magnitude of the
restoring force to be applied. Contrary to conventional wisdom, i.e. that a
more precise measurement is expected to improve the system stability, here we
demonstrate that a certain degree of measurement error can improve the system
stability. We exemplify the implications of this finding with numerical
examples drawn from various fields, such as the operation of a temperature
controller, the confinement of a microscopic particle, the localization of a
target by a microswimmer, and the control of a population.


title:
Garoufalidis-Levine's finite type invariants for
  $\mathbb{Z}\pi$-homology equivalences from 3-manifolds to the 3-torus

abstract:
  Garoufalidis and Levine defined a filtration for 3-manifolds equipped with
some degree 1 map ($\mathbb{Z}\pi$-homology equivalence) to a fixed 3-manifold
$N$ and showed that there is a natural surjection from a space of
$\pi=\pi_1N$-decorated graphs to the graded quotient of the filtration over
$\mathbb{Z}[\frac{1}{2}]$. In this paper, we show that in the case of $N=T^3$
the surjection of Garoufalidis--Levine is actually an isomorphism over
$\mathbb{Q}$. For the proof, we construct a perturbative invariant by applying
Fukaya's Morse homotopy theoretic construction to a local system of the
quotient field of $\mathbb{Q}\pi$. The first invariant is an extension of the
Casson invariant to $\mathbb{Z}\pi$-homology equivalences to the 3-torus. The
results of this paper suggest that there is a highly nontrivial equivariant
quantum invariants for 3-manifolds with $b_1=3$. We also discuss some
generalizations of the perturbative invariant for other target spaces $N$.


title: Noncommutative reality-based algebras of rank 6

abstract:
  We classify the RBA-bases of $6$-dimensional noncommutative semisimple
algebras for which the algebra has a positive degree map. We show that these
RBAs are parametrized by seven real numbers, the first four of which are
positive and the remaining three arbitrary. Our classification gives formulas
for their standard bases and structure constants. Using these we give a list of
all noncommutative integral table algebras of rank 6 with order up to 150. Four
in the list are primitive, but we show these cannot be realized as adjacency
algebras of association schemes. In the last section of the paper we apply our
methods to give a precise description of the noncommutative integral table
algebras of rank 6 for which the multiplicity of both linear characters is 1.


title:
Existence of small loops in the Bifurcation diagram near the degenerate
  eigenvalues

abstract:
  In this paper we study for the incompressible Euler equations the global
structure of the bifurcation diagram for the rotating doubly connected patches
near the degenerate case. We show that the branches with the same symmetry
merge forming a small loop provided that they are close enough. This confirms
the numerical observations done in the recent work [10]


title:
Intelligent Pinning Based Cooperative Secondary Control of Distributed
  Generators for Microgrid in Islanding Operation Mode

abstract:
  Motivated by the fact that the location(s) and structural properties of the
pinning node(s) affect the algebraic connectivity of a network with respect to
the reference value and thereby, its dynamic performance, this paper studies
the application of intelligent single and multiple pinning of distributed
cooperative secondary control of distributed generators (DGs) in islanded
microgrid operation. It is shown that the intelligent selection of a pinning
set based on the degree of connectivity and distance of leader DG(s) from the
rest of the network improves the transient performance for microgrid voltage
and frequency regulation. The efficacy of the distributed control strategy
based on the proposed algorithms is illustrated via numerical results
simulating typical scenarios for a variety of microgrid configurations.


title:
Fractional calculus and path-wise integration for Volterra processes
  driven by L\'evy and martingale noise

abstract:
  We introduce a pathwise integration for Volterra processes driven by L\'evy
noise or martingale noise. These processes are widely used in applications to
turbulence, signal processes, biology, and in environmental finance. Indeed
they constitute a very flexible class of models, which include fractional
Brownian and L\'evy motions and it is part of the so-called ambit fields. A
pathwise integration with respect of such Volterra processes aims at producing
a framework where modelling is easily understandable from an information
perspective. The techniques used are based on fractional calculus and in this
there is a bridging of the stochastic and deterministic techniques. The present
paper aims at setting the basis for a framework in which further computational
rules can be devised. Our results are general in the choice of driving noise.
Additionally we propose some further details in the relevant context
subordinated Wiener processes.


title:
Magnetic properties of bilayer Sr$_3$Ir$_2$O$_7$: role of epitaxial
  strain and oxygen vacancies

abstract:
  Using {\it ab initio} methods, we investigate the modification of the
magnetic properties of the $m=2$ member of the strontium iridates
Ruddlesden-Popper series Sr$_{m+1}$Ir$_{m}$O$_{3m+1}$, bilayer
Sr$_3$Ir$_2$O$_7$, induced by epitaxial strain and oxygen vacancies. Unlike the
single layer compound Sr$_2$IrO$_4$, which exhibits a robust in-plane magnetic
order, the energy difference between in-plane and out-of-plane magnetic
orderings in Sr$_3$Ir$_2$O$_7$ is much smaller and it is expected that small
external perturbations could induce magnetic transitions. Our results indicate
that epitaxial strain yields a spin-flop transition, that is driven by the
crossover between the intralayer $J_1$ and interlayer $J_2$ magnetic exchange
interactions upon compressive strain. While $J_1$ is essentially insensitive to
strain effects, the strength of $J_2$ changes by one order of magnitude for
tensile strains $\geq$ 3~\%. In addition, our study clarifies that the unusual
in-plane magnetic response observed in Sr$_3$Ir$_2$O$_7$ upon the application
of an external magnetic field originates from the canting of the local magnetic
moments due to oxygen vacancies, which tilt the octahedral networks - thereby
allowing for noncollinear spin configurations.


title: Sparse Bayesian time-varying covariance estimation in many dimensions

abstract:
  We address the curse of dimensionality in dynamic covariance estimation by
modeling the underlying co-volatility dynamics of a time series vector through
latent time-varying stochastic factors. The use of a global-local shrinkage
prior for the elements of the factor loadings matrix pulls loadings on
superfluous factors towards zero. To demonstrate the merits of the proposed
framework, the model is applied to simulated data as well as to daily
log-returns of 300 S&P 500 members. Our approach yields precise correlation
estimates, strong implied minimum variance portfolio performance and superior
forecasting accuracy in terms of log predictive scores when compared to typical
benchmarks.

categories: stat.ME econ.EM q-fin.PM stat.AP stat.CO


title:
On the Efficiency and Fairness of Multiplayer HTTP-based Adaptive Video
  Streaming

abstract:
  User-perceived quality-of-experience (QoE) is critical in internet video
delivery systems. Extensive prior work has studied the design of client-side
bitrate adaptation algorithms to maximize single-player QoE. However,
multiplayer QoE fairness becomes critical as the growth of video traffic makes
it more likely that multiple players share a bottleneck in the network. Despite
several recent proposals, there is still a series of open questions. In this
paper, we bring the problem space to light from a control theory perspective by
formalizing the multiplayer QoE fairness problem and addressing two key
questions in the broader problem space. First, we derive the sufficient
conditions of convergence to steady state QoE fairness under TCP-based
bandwidth sharing scheme. Based on the insight from this analysis that
in-network active bandwidth allocation is needed, we propose a non-linear
MPC-based, router-assisted bandwidth allocation algorithm that regards each
player as closed-loop systems. We use trace-driven simulation to show the
improvement over existing approaches. We identify several research directions
enabled by the control theoretic modeling and envision that control theory can
play an important role on guiding real system design in adaptive video
streaming.


title:
Ultrafast terahertz-field-driven ionic response in ferroelectric
  BaTiO$_3$

abstract:
  The dynamical processes associated with electric field manipulation of the
polarization in a ferroelectric remain largely unknown but fundamentally
determine the speed and functionality of ferroelectric materials and devices.
Here we apply sub-picosecond duration, single-cycle terahertz pulses as an
ultrafast electric field bias to prototypical BaTiO$_3$ ferroelectric thin
films with the atomic-scale response probed by femtosecond x-ray scattering
techniques. We show that electric fields applied perpendicular to the
ferroelectric polarization drive large amplitude displacements of the titanium
atoms along the ferroelectric polarization axis, comparable to that of the
built-in displacements associated with the intrinsic polarization and
incoherent across unit cells. This effect is associated with a dynamic rotation
of the ferroelectric polarization switching on and then off on picosecond
timescales. These transient polarization modulations are followed by long-lived
vibrational heating effects driven by resonant excitation of the ferroelectric
soft mode, as reflected in changes in the c-axis tetragonality. The ultrafast
structural characterization described here enables direct comparison with
first-principles-based molecular dynamics simulations, with good agreement
obtained.


title:
New Methods to Improve Large-Scale Microscopy Image Analysis with Prior
  Knowledge and Uncertainty

abstract:
  Multidimensional imaging techniques provide powerful ways to examine various
kinds of scientific questions. The routinely produced datasets in the
terabyte-range, however, can hardly be analyzed manually and require an
extensive use of automated image analysis. The present thesis introduces a new
concept for the estimation and propagation of uncertainty involved in image
analysis operators and new segmentation algorithms that are suitable for
terabyte-scale analyses of 3D+t microscopy images.


title:
ALLSAT compressed with wildcards: From CNF's to orthogonal DNF's by
  imposing the clauses one by one

abstract:
  We present a novel technique for converting a Boolean CNF into an orthogonal
DNF, aka exclusive sum of products. Our method (which will be pitted against a
hardwired command from Mathematica) zooms in on the models of the CNF by
imposing its clauses one by one. Clausal Imposition invites parallelization,
and wildcards beyond the common don't-care symbol compress the output. The
method is most efficient for few but large clauses. Generalizing clauses one
can in fact impose superclauses. By definition, superclauses are obtained from
clauses by substituting each positive litereal by an arbitrary conjunction of
positive literals.


title: Critical parameter of random loop model on trees

abstract:
  We give estimates of the critical parameter for random loop models that are
related to quantum spin systems. A special case of the model that we consider
is the interchange- or random-stirring process. We consider here the model
defined on regular trees of large degrees, which are expected to approximate
high spatial dimensions. We find a critical parameter that indeed shares
similarity with existing numerical results for the cubic lattice. In the case
of the interchange process our results improve on earlier work by Angel and by
Hammond, in that we determine the second-order term of the critical parameter.


title: Empirical and Strong Coordination via Soft Covering with Polar Codes

abstract:
  We design polar codes for empirical coordination and strong coordination in
two-node networks. Our constructions hinge on the fact that polar codes enable
explicit low-complexity schemes for soft covering. We leverage this property to
propose explicit and low-complexity coding schemes that achieve the capacity
regions of both empirical coordination and strong coordination for sequences of
actions taking value in an alphabet of prime cardinality. Our results improve
previously known polar coding schemes, which (i) were restricted to uniform
distributions and to actions obtained via binary symmetric channels for strong
coordination, (ii) required a non-negligible amount of common randomness for
empirical coordination, and (iii) assumed that the simulation of discrete
memoryless channels could be perfectly implemented. As a by-product of our
results, we obtain a polar coding scheme that achieves channel resolvability
for an arbitrary discrete memoryless channel whose input alphabet has prime
cardinality.


title: A local relative trace formula for PGL(2)

abstract:
  Following a scheme inspired by B. Feigon, we describe the spectral side of a
local relative trace formula for $G:= PGL(2,\rm E)$ relative to the symmetric
subgroup $H:=PGL(2,\rm F)$ where $\rm E/\rm F$ is an unramified quadratic
extension of local non archimedean fields of characteristic $0$. This spectral
side is given in terms of regularized normalized periods and normalized
$C$-functions of Harish-Chandra. Using the geometric side obtained in a more
general setting by P. Delorme, P. Harinck and S. Souaifi , we deduce a local
relative trace formula for $G$ relative to $H$. We apply our result to invert
some orbital integrals.


title:
Diffusive stability of spatially periodic solutions of the Brusselator
  model

abstract:
  Applying the Lyapunov-Schmidt reduction approach introduced by Mielke and
Schneider in their analysis of the fourth-order scalar Swift-Hohenberg
equation, we carry out a rigorous small-amplitude stability analysis of Turing
patterns for the canonical second-order system of reaction diffusion equations
given by the Brusselator model. Our results confirm that stability is
accurately predicted in the small-amplitude limit by the formal Ginzburg Landau
amplitude equations, rigorously validating the standard weakly unstable
approximation and Eckhaus criterion.


title: Strongly Gapped Spin-Wave Excitation in the Insulating Phase of NaOsO3

abstract:
  NaOsO3 hosts a rare manifestation of a metal-insulator transition driven by
magnetic correlations, placing the magnetic exchange interactions in a central
role. We use resonant inelastic x-ray scattering to directly probe these
magnetic exchange interactions. A dispersive and strongly gapped (58 meV)
excitation is observed indicating appreciable spin-orbit coupling in this 5d3
system. The excitation is well described within a minimal model Hamiltonian
with strong anisotropy and Heisenberg exchange (J1=J2=13.9 meV). The observed
behavior places NaOsO3 on the boundary between localized and itinerant
magnetism.


title:
Short- and long-range corrected hybrid density functionals with the D3
  dispersion corrections

abstract:
  We propose a short- and long-range corrected (SLC) hybrid scheme employing
100% Hartree-Fock (HF) exchange at both zero and infinite interelectronic
distances, wherein three SLC hybrid density functionals with the D3 dispersion
corrections (SLC-LDA-D3, SLC-PBE-D3, and SLC-B97-D3) are developed. SLC-PBE-D3
and SLC-B97-D3 are shown to be accurate for a very diverse range of
applications, such as core ionization and excitation energies, thermochemistry,
kinetics, noncovalent interactions, dissociation of symmetric radical cations,
vertical ionization potentials, vertical electron affinities, fundamental gaps,
and valence, Rydberg, and long-range charge-transfer excitation energies.
Relative to omegaB97X-D, SLC-B97-D3 provides significant improvement for core
ionization and excitation energies and noticeable improvement for the
self-interaction, asymptote, energy-gap, and charge-transfer problems, while
performing similarly for thermochemistry, kinetics, and noncovalent
interactions.

categories: physics.chem-ph physics.atom-ph physics.comp-ph quant-ph


title:
Exactly solvable $N$-body quantum systems with $N=3^k \ ( k \geq 2)$ in
  the $D=1$ dimensional space

abstract:
  We study the exact solutions of a particular class of $N$ confined particles
of equal mass, with $N=3^k \ (k=2,3,...),$ in the $D=1$ dimensional space. The
particles are clustered in clusters of 3 particles. The interactions involve a
confining mean field, two-body Calogero type of potentials inside the cluster,
interactions between the centres of mass of the clusters and finally a
non-translationally invariant $N$-body potential. The case of 9 particles is
exactly solved, in a first step, by providing the full eigensolutions and
eigenenergies. Extending this procedure, the general case of $N$ particles
($N=3^k, \ k \geq 2$) is studied in a second step. The exact solutions are
obtained via appropriate coordinate transformations and separation of
variables. The eigenwave functions and the corresponding energy spectrum are
provided.


title: An Unoriented Variation on de Bruijn Sequences

abstract:
  For positive integers $k,n$, a de Bruijn sequence $B(k,n)$ is a finite
sequence of elements drawn from $k$ characters whose subwords of length $n$ are
exactly the $k^n$ words of length $n$ on $k$ characters. This paper introduces
the unoriented de Bruijn sequence $uB(k,n)$, an analog to de Bruijn sequences,
but for which the sequence is read both forwards and backwards to determine the
set of subwords of length $n$. We show that nontrivial unoriented de Bruijn
sequences of optimal length exist if and only if $k$ is two or odd and $n$ is
less than or equal to 3. Unoriented de Bruijn sequences for any $k$, $n$ may be
constructed from certain Eulerian paths in Eulerizations of unoriented de
Bruijn graphs.


title:
Stable Equilibria of Anisotropic Particles on Substrates: a Generalized
  Winterbottom Construction

abstract:
  We present a new approach for predicting stable equilibrium shapes of
crystalline islands on flat substrates, as commonly occur through solid-state
dewetting of thin films. The new theory is a generalization of the widely used
Winterbottom construction i.e., an extension of the Wulff construction for
particles on substrates). This approach is equally applicable to cases where
the crystal surface energy is isotropic, weakly anisotropic, strongly
anisotropic and "cusped". We demonstrate that, unlike in the classical
Winterbottom approach, multiple equilibrium island shapes may be possible when
the surface energy is strongly anisotropic. We analyze these shapes through
perturbation analysis, by calculating the first and second variations of the
total free energy functional with respect to contact locations and island
shape. Based on this analysis, we find the necessary conditions for stable
equilibria and exploit this through a generalization of the Winterbottom
construction to identify all possible stable equilibrium shapes. Finally, we
propose a dynamical evolution method based on surface diffusion mass transport
to determine whether all of the stable equilibrium shapes are dynamically
accessible. Applying this approach, we demonstrate that islands with different
initial shapes may evolve into different stationary shapes and show that these
dynamically-determined stationary states correspond to the predicted stable
equilibrium shapes, as obtained from the generalized Winterbottom construction.


title:
Distributional properties and parameters estimation of GSB Process: An
  approach based on characteristic functions

abstract:
  A general type of a Split-BREAK process with Gaussian innovations
(henceforth, Gaussian Split-BREAK or GSB process) is considered. The basic
stochastic properties of the model are studied and its characteristic function
derived. A procedure to estimate the parameter of the GSB model based on the
Empirical Characteristic Function (ECF) is proposed. Our simulations suggest
that the proposed method performs well compared to a Method of Moment procedure
used as benchmark. The empirical use of the GSB model is illustrated with an
application to the time series of total values of shares traded at Belgrade
Stock Exchange.


title: WNetKAT: A Weighted SDN Programming and Verification Language

abstract:
  Programmability and verifiability lie at the heart of the software-defined
networking paradigm. While OpenFlow and its match-action concept provide
primitive operations to manipulate hardware configurations, over the last
years, several more expressive network programming languages have been
developed. This paper presents WNetKAT, the first network programming language
accounting for the fact that networks are inherently weighted, and
communications subject to capacity constraints (e.g., in terms of bandwidth)
and costs (e.g., latency or monetary costs). WNetKAT is based on a syntactic
and semantic extension of the NetKAT algebra. We demonstrate several relevant
applications for WNetKAT, including cost- and capacity-aware reachability, as
well as quality-of-service and fairness aspects. These applications do not only
apply to classic, splittable and unsplittable (s; t)-flows, but also generalize
to more complex network functions and service chains. For example, WNetKAT
allows to model flows which need to traverse certain waypoint functions, which
may change the traffic rate. This paper also shows the relation between the
equivalence problem of WNetKAT and the equivalence problem of the weighted
finite automata, which implies undecidability of the former. However, this
paper also succeeds to prove the decidability of another useful problem, which
is sufficient in many practical scnearios: whether an expression equals to 0.
Moreover, we initiate the discussion of decidable subsets of the whole
language.


title: Opinion Manipulation in Social Networks

abstract:
  In this work, we are interested in finding the most efficient use of a budget
to promote an opinion by paying agents within a group to supplant their true
opinions. We model opinions as continuous scalars ranging from 0 to 1 with 1
(0) representing extremely positive (negative) opinion. We focus on asymmetric
confidence between agents. The iterative update of an agent corresponds to the
best response to other agents' actions. The resulting confidence matrix can be
seen as an equivalent Markov chain. We provide simple and efficient algorithms
to solve this problem and we show through an example how to solve the stated
problem in practice.


title:
Potential outcome approach to causal inference in assessing the short
  term impact of air pollution on mortality

abstract:
  The opportunity to assess short term impact of air pollution relies on the
causal interpretation of the exposure-outcome association, but up to now few
studies explicitly faced this issue within a causal inference framework. In
this paper, we reformulated the problem of assessing the short term impact of
air pollution on health using the potential outcome approach to causal
inference. We focused on the impact of high daily levels of PM10 on mortality
within two days from the exposure in the metropolitan area of Milan (Italy),
during the period 2003-2006. After defining the number of attributable deaths
in terms of difference between potential outcomes, we used the estimated
propensity score to match each high exposure-day with a day with similar
background characteristics but lower PM10 level. Then, we estimated the impact
by comparing mortality between matched days. We found that during the study
period daily exposures larger than 40 microgram per cubic meter were
responsible of 1079 deaths (116; 2042). The impact was more evident among the
elderly than in the younger classes of age. The propensity score matching
turned out to be an appealing method to assess historical impacts in this
field.


title:
Study of baryon acoustic oscillations with SDSS DR12 data and
  measurements of $\Omega_k$ and $\Omega_\textrm{DE}(a)$. Part II

abstract:
  We define Baryon Acoustic Oscillation (BAO) observables $\hat{d}_\alpha(z,
z_c)$, $\hat{d}_z(z, z_c)$, and $\hat{d}_/(z, z_c)$ that do not depend on any
cosmological parameter. From each of these observables we recover the BAO
correlation length $d_\textrm{BAO}$ with its respective dependence on
cosmological parameters. These BAO observables are measured as a function of
redshift $z$ with the Sloan Digital Sky Survey (SDSS) data release DR12. From
the BAO measurements alone, or together with the correlation angle
$\theta_\textrm{MC}$ of the Cosmic Microwave Background (CMB), we constrain the
curvature parameter $\Omega_k$ and the dark energy density
$\Omega_\textrm{DE}(a)$ as a function of the expansion parameter $a$ in several
scenarios. These observables are further constrained with external measurements
of $h$ and $\Omega_\textrm{b} h^2$. We find some tension between the data and a
cosmology with flat space and constant dark energy density
$\Omega_\textrm{DE}(a)$.


title:
Towards High-Resolution Mercury Global Topography from MESSENGER Orbital
  Stereo Imaging - A Prototype Model for the H6 Quadrangle "Kuiper"

abstract:
  We selected approximately 10,500 Narrow Angle Camera (NAC) and Wide-Angle
Camera (WAC) stereo images obtained by the MESSENGER spacecraft during its
orbital mission with average resolutions of 150 m/pixel to compute a Digital
Terrain Model (DTM) for the so-called H6 quadrangle (Kuiper), extending between
22.5{\deg}S to 22.5{\deg}N and 288.0{\deg}E to 360.0{\deg}E. Among the images,
we identified about 21,100 stereo image combinations with each combination
consisting of at least 3 images. We applied sparse multi-image matching to
derive approximately 250,000 tie-points representing 50,000 ground points. We
used the tie-points to carry out a photogrammetric block adjustment, which
improves the image pointing and the accuracy of (3D) ground points from about
850 m to approximately 55 m. Subsequently, we applied high density
(pixel-by-pixel) multi-image matching to derive about 45 billion tie-points.
Benefitting from improved image pointing data, we compute about 6.3 billion
surface points. By interpolation, we generated a DEM with a lateral spacing of
221.7 m/pixel (192 pixels per degree) and a vertical accuracy of about 30 m.
The comparison of the DEM with the Mercury Laser Altimeter (MLA) tracks
obtained over 4 years of MESSENGER operation reveals that the DEM is
geometrically very rigid. It may be used as a reference to identify MLA
outliers (when MLA operating at ranging limit) or to map offsets of laser
altimeter tracks, presumably caused by residual spacecraft orbit and attitude
errors. After the relevant outlier removal and corrections, MLA profiles show
excellent agreement with topographic profiles from H6 with root mean square
height difference of only 88 m.


title:
Crustal control of dissipative ocean tides in Enceladus and other icy
  moons

abstract:
  Could tidal dissipation within Enceladus' subsurface ocean account for the
observed heat flow? Earthlike models of dynamical tides give no definitive
answer because they neglect the influence of the crust. I propose here the
first model of dissipative tides in a subsurface ocean, by combining the
Laplace Tidal Equations with the membrane approach. For the first time, it is
possible to compute tidal dissipation rates within the crust, ocean, and mantle
in one go. I show that oceanic dissipation is strongly reduced by the crustal
constraint, and thus contributes little to Enceladus' present heat budget.
Tidal resonances could have played a role in a forming or freezing ocean less
than 100 m deep. The model is general: it applies to all icy satellites with a
thin crust and a shallow ocean. Scaling rules relate the resonances and
dissipation rate of a subsurface ocean to the ones of a surface ocean. If the
ocean has low viscosity, the westward obliquity tide does not move the crust.
Therefore, crustal dissipation due to dynamical obliquity tides can differ from
the static prediction by up to a factor of two.


title: New refiners for permutation group search

abstract:
  We describe how orbital graphs can be used to improve the practical
performance of many algorithms for permutation groups, including intersection
and stabilizer problems. First we explain how orbital graphs can be integrated
in partition backtracking, the current state of the art algorithm for many
permutation group problems. We then show how our algorithms perform in
practice, demonstrating improvements of several orders of magnitude for some
problems.


title: Multi-period investment strategies under Cumulative Prospect Theory

abstract:
  In this article, inspired by Shi, et al. we investigate the optimal portfolio
selection with one risk-free asset and one risky asset in a multiple period
setting under cumulative prospect theory (CPT). Compared with their study, our
novelty is that we consider a stochastic benchmark, and portfolio constraints.
We test the sensitivity of the optimal CPT-investment strategies to different
model parameters by performing a numerical analysis.


title: Fan realizations for some 2-associahedra

abstract:
  A~$k$-associahedron is a simplicial complex whose facets,
called~$k$-triangulations, are the inclusion maximal sets of diagonals of a
convex polygon where no~$k+1$ diagonals mutually cross. Such complexes are
conjectured for about a decade to have realizations as convex polytopes, and
therefore as complete simplicial fans. Apart from four one-parameter families
including simplices, cyclic polytopes and classical associahedra, only two
instances of multiassociahedra have been geometrically realized so far. This
paper reports on conjectural realizations for all~$2$-associahedra, obtained by
heuristic methods arising from natural geometric intuition on subword
complexes. Experiments certify that we obtain fan realizations
of~$2$-associahedra of an~$n$-gon for~$n\in\{10,11,12,13\}$, further ones being
out of our computational reach.


title: Separating Components of Attention and Surprise

abstract:
  Cognitive processes involved in both allocation of attention during decision
making as well as surprise when making mistakes trigger release of the
neurotransmitter norepinephrine, which has been shown to be correlated with an
increase in pupil dilation, in turn reflecting raised levels of arousal.
Extending earlier experiments based on the Attention Network Test (ANT),
separating the neural components of alertness and spatial re-orientation from
the attention involved in more demanding conflict resolution tasks, we
demonstrate that these signatures of attention are so robust that they may be
retrieved even when applying low cost eye tracking in an everyday mobile
computing context. Furthermore we find that the reaction of surprise elicited
when committing mistakes in a decision task, which in the neuroimaging EEG
literature have been referred to as a negativity feedback error correction
signal, may likewise be retrieved solely based on an increase in pupil
dilation.


title:
Discrete mean square of the Riemann zeta-function over imaginary parts
  of its zeros

abstract:
  Assume the Riemann hypothesis. On the right-hand side of the critical strip,
we obtain an asymptotic formula for the discrete mean square of the Riemann
zeta-function over imaginary parts of its zeros.


title: Recent progress on superstrange dynamics

abstract:
  We review the present activities related to hypernuclear production in
hadronic in-medium reactions at intermediate energies. The status of
theoretical predictions and experimental evidences for the in-medium formation
of bound superstrange matter is discussed. Heavy-ion collisions and
antiproton-induced reactions at energies close to strangeness production
thresholds create the conditions of hypermatter formation. This allows to
understand better in-medium hyperon interactions and sets constraints on the
strangeness sector of the nuclear equation of state.


title:
Wang-Landau algorithm for entropic sampling of arch-based microstates in
  the volume ensemble of static granular packings

abstract:
  We implement the Wang-Landau algorithm to sample with equal probabilities the
static configurations of a model granular system. The "non-interacting rigid
arch model" used is based on the description of static configurations by means
of splitting the assembly of grains into sets of stable arches. This technique
allows us to build the entropy as a function of the volume of the packing for
large systems. We make a special note of the details that have to be considered
when defining the microstates and proposing the moves for the correct sampling
in these unusual models. We compare our results with previous exact
calculations of the model made at moderate system sizes. The technique opens a
new opportunity to calculate the entropy of more complex granular models.


title:
3.3 cm JVLA observations of transitional disks: searching for centimeter
  pebbles

abstract:
  We present sensitive (rms-noises $\sim$ 4 -- 25 $\mu$Jy) and high angular
resolution ($\sim$1--2$"$) 8.9 GHz (3.3 cm) Karl G. Jansky Very Large Array
(JVLA) radio continuum observations of 10 presumed transitional disks
associated with young low-mass stars. We report the detection of radio
continuum emission in 5 out of the 10 objects (RXJ1615, UX Tau A, LkCa15,
RXJ1633, and SR24s). In the case of LkCa15, the centimeter emission is
extended, and has a similar morphology to that of the transitional disk
observed at mm wavelengths with an inner depression. For these five detections,
we construct the Spectral Energy Distributions (SEDs) from the centimeter to
submillimeter wavelengths, and find that they can be well fitted with a single
(RXJ 1633 and UX Tau A) or a two component power-law (LkCa 15, RXJ 1615, and
SR24s). For the cases where a single power-law fits well the data, the
centimeter emission is likely produced by optically thin dust with large grains
i.e. centimeter-size pebbles) present in the transitional disks. For the cases
where a double power-law fits the data, the centimeter emission might be
produced by the combination of photoevaporation and/or a free-free jet. We
conclude that RXJ1633 and UX Tau A are excellent examples of transitional disks
where the structure of the emission from centimeter/millimeter pebbles can be
studied. In the other cases, some other physical emitting mechanisms are also
important in the centimeter regime.


title:
Modelling Cyber-Security Experts' Decision Making Processes using
  Aggregation Operators

abstract:
  An important role carried out by cyber-security experts is the assessment of
proposed computer systems, during their design stage. This task is fraught with
difficulties and uncertainty, making the knowledge provided by human experts
essential for successful assessment. Today, the increasing number of
progressively complex systems has led to an urgent need to produce tools that
support the expert-led process of system-security assessment. In this research,
we use weighted averages (WAs) and ordered weighted averages (OWAs) with
evolutionary algorithms (EAs) to create aggregation operators that model parts
of the assessment process. We show how individual overall ratings for security
components can be produced from ratings of their characteristics, and how these
individual overall ratings can be aggregated to produce overall rankings of
potential attacks on a system. As well as the identification of salient attacks
and weak points in a prospective system, the proposed method also highlights
which factors and security components contribute most to a component's
difficulty and attack ranking respectively. A real world scenario is used in
which experts were asked to rank a set of technical attacks, and to answer a
series of questions about the security components that are the subject of the
attacks. The work shows how finding good aggregation operators, and identifying
important components and factors of a cyber-security problem can be automated.
The resulting operators have the potential for use as decision aids for systems
designers and cyber-security experts, increasing the amount of assessment that
can be achieved with the limited resources available.


title:
Systemic stability, cell differentiation, and evolution - A dynamical
  systems perspective

abstract:
  Species or population that proliferate faster than others become dominant in
numbers. Catalysis allows catalytic sets within a molecular reaction network to
dominate the non catalytic parts of the network by processing most of the
available substrate. As a consequence one may consider a 'catalytic fitness' of
sets of molecular species. The fittest sets emerge as the expressed chemical
backbone or sub-network of larger chemical reaction networks employed by
organisms. However, catalytic fitness depends on the systemic context and the
stability of systemic dynamics. Unstable reaction networks would easily be
reshaped or destroyed by fluctuations of the chemical environment. In this
paper we therefore focus on recognizing systemic stability as an evolutionary
selection criterion. In fact, instabilities of regulatory systems dynamics
become predictive for associated evolutionary forces driving the emergence
large reaction networks that avoid or control inherent instabilities. Systemic
instabilities can be identified and analyzed using relatively simple
mathematical random networks models of complex regulatory systems. Using a
statistical ensemble approach one can identify fundamental causes of instable
dynamics, infer evolutionary preferred network properties, and predict
evolutionary emergent control mechanisms and their entanglement with cell
differentiation processes. Surprisingly, what systemic stability tells us here
is that cells (or other non-linear regulatory systems) never had to learn how
to differentiate, but rather how to avoid and control differentiation. For
example, in this framework we can predict that regulatory systems will
evolutionary favor networks where the number of catalytic enhancers is not
larger than the number of suppressors.


title:
Statistical evolution of quiet-Sun small scale magnetic features using
  Sunrise observations

abstract:
  The evolution of small magnetic features in quiet regions of the Sun provides
a unique window to probing solar magneto-convection. Here we analyze small
scale magnetic features in the quiet Sun, using the high resolution,
seeing-free observations from the Sunrise balloon borne solar observatory. Our
aim is to understand the contribution of different physical processes, such as
splitting, merging, emergence and cancellation of magnetic fields to the
rearrangement, addition and removal of magnetic flux in the photosphere. We
employ a statistical approach for the analysis and the evolution studies are
carried out using a feature tracking technique. In this paper we provide a
detailed description of the feature tracking algorithm that we have newly
developed and we present the results of a statistical study of several physical
quantities. The results on the fractions of the flux in the emergence,
appearance, splitting, merging, disappearance and cancellation qualitatively
agrees with other recent studies. To summarize, the total flux gained in
unipolar appearance is an order of magnitude larger than the total flux gained
in emergence. On the other hand, the bi-polar cancellation contributes nearly
an equal amount to the loss of magnetic flux as unipolar disappearance. The
total flux lost in cancellation is nearly $6-8$ times larger than the total
flux gained in emergence. One big difference between our study and previous
similar studies is that thanks to the higher spatial resolution of Sunrise we
can track features with fluxes as low as $9\times10^{14}$ Mx. This flux is
nearly an order of magnitude lower than the smallest fluxes of the features
tracked in the highest resolution previous studies based on Hinode data.


title: Collaborative Delivery with Energy-Constrained Mobile Robots

abstract:
  We consider the problem of collectively delivering some message from a
specified source to a designated target location in a graph, using multiple
mobile agents. Each agent has a limited energy which constrains the distance it
can move. Hence multiple agents need to collaborate to move the message, each
agent handing over the message to the next agent to carry it forward. Given the
positions of the agents in the graph and their respective budgets, the problem
of finding a feasible movement schedule for the agents can be challenging. We
consider two variants of the problem: in non-returning delivery, the agents can
stop anywhere; whereas in returning delivery, each agent needs to return to its
starting location, a variant which has not been studied before.
  We first provide a polynomial-time algorithm for returning delivery on trees,
which is in contrast to the known (weak) NP-hardness of the non-returning
version. In addition, we give resource-augmented algorithms for returning
delivery in general graphs. Finally, we give tight lower bounds on the required
resource augmentation for both variants of the problem. In this sense, our
results close the gap left by previous research.


title: Leptoquark model to explain the $B$-physics anomalies, $R_K$ and $R_D$

abstract:
  We show that a model with a scalar leptoquark of hypercharge $Y=1/6$ which
includes the light right-handed neutrinos, can successfully describe both of
the $B$-physics anomalies, $R_K^{\rm exp} < R_K^{\rm SM}$ and $R_D^{\rm exp} >
R_D^{\rm SM}$. We discuss the corresponding low energy effective theory and,
after using the known experimental data as constraints, we show that the model
is viable and that it offers several predictions which can be tested
experimentally.


title: Approximative Wigner function for the Helium atom and dissipation

abstract:
  The Schr\"odinger equation in phase space is used to calculate the Wigner
function for the Helium atom in the approximation of a system of two
oscillators. Dissipation effect is analysed and the non-classicality of the
state is studied by the non-classicality indicator of the Wigner function,
which is calculated as a function of the dissipation parameter.


title: Study of the Power-Law Fluctuations in the Email Size

abstract:
  In a previous study, we investigated the frequency distribution of the email
size in the system log data of the main email server for the staff on a campus
network. We found that the frequencies of email sizes followed a power-law
distribution and discovered two inflection points in the distribution. After
analyzing these results, we collected new system log data for both staff and
students for the period from April 1, 2009 to March 31, 2015 and analyzed the
frequency distributions per academic year. The results of the earlier
investigation were replicated for each of these distributions. Then, we
disaggregated the system log data for the staff for the period from May 1, 2015
to July 31, 2015 using the email header "Content-Type" and created four
subdistributions. Frequency distributions were calculated for the disaggregated
data. We then proposed and evaluated a model to explain the overall frequency
distribution as a sum of the four subdistributions. The correlation coefficient
between the observed frequency distribution and the distribution predicted by
our model was 0.8408 for the staff. This coefficient confirmed that our
approach can successfully model and predict the size distribution of emails.


title: Abelian Yang-Baxter Deformations and TsT transformations

abstract:
  We prove that abelian Yang-Baxter deformations of superstring coset sigma
models are equivalent to sequences of commuting TsT transformations, meaning T
dualities and coordinate shifts. Our results extend also to fermionic
deformations and fermionic T duality, and naturally lead to a TsT subgroup of
the superduality group OSp(d_b,d_b|2d_f). In cases like AdS_5 x S^5, fermionic
deformations necessarily lead to complex models. As an illustration of
inequivalent deformations, we give all six abelian deformations of AdS_3. We
comment on the possible dual field theory interpretation of these (super-)TsT
models.


title: Placing Arrows in Directed Graph Drawings

abstract:
  We consider the problem of placing arrow heads in directed graph drawings
without them overlapping other drawn objects. This gives drawings where edge
directions can be deduced unambiguously. We show hardness of the problem,
present exact and heuristic algorithms, and report on a practical study.


title:
On the nature of discrete space-time: The atomic theory of space-time
  and its effects on Pythagoras's theorem, time versus duration, inertial
  anomalies of astronomical bodies, and special relativity at the Planck scale

abstract:
  In this work, resolutions will be given for commonly stated problems
associated with a model that assumes that space and time are discretized (i.e.,
atomized). This model is in contrast to the continuous space-time model that is
used in all common physical theories and equations -- a model that assumes that
spatial coordinates and time are continuous variables. The resolutions to the
problems are arrived at, not by proposing any new theories or postulates, but
by strictly adhering to: Ernst Mach's principle of non-absolute space, the
tenets of logical positivism, quantum mechanics and general relativity. The
problems associated with discrete space-time addressed in this paper include:
Lorentz contraction (time dilation) of the ostensibly smallest spatial
(temporal) interval, maintaining isotropy, violations of causality, and
conservation of energy and momentum. Importantly, this work yields
modifications to the standard formulae for time dilation and length
contraction, with these modifications preserving the quantums of space and time
and allowing for temporary travel at the speed of light. Also given are: a
resolution to Weyl's tile argument, a modification of the 2500 year old
Pythagoras's theorem, a reassessment of Henri Bergson's theory advocating a
distinction between the time durations measured by scientists and an immutable
"Time", and a discussion of whether Einstein's light-clocks are as ideal as
most scientist believe. Also included is a demonstration of how discrete space
imposes order upon John Wheeler's quantum foam such that the foam becomes a
gravity crystal permeating all space and producing measurable inertial
anomalies of astronomical bodies.


title:
Theoretical approaches to the steady-state statistical physics of
  interacting dissipative units

abstract:
  The aim of this review is to provide a concise overview of some of the
generic approaches that have been developed to deal with the statistical
description of large systems of interacting dissipative 'units'. The latter
notion includes, e.g., inelastic grains, active or self-propelled particles,
bubbles in a foam, low-dimensional dynamical systems like driven oscillators,
or even spatially extended modes like Fourier modes of the velocity field in a
fluid for instance. We first review methods based on the statistical properties
of a single unit, starting with elementary mean-field approximations, either
static or dynamic, that describe a unit embedded in a 'self-consistent'
environment. We then discuss how this basic mean-field approach can be extended
to account for spatial dependences, in the form of space-dependent mean-field
Fokker-Planck equations for example. We also briefly review the use of kinetic
theory in the framework of the Boltzmann equation, which is an appropriate
description for dilute systems. We then turn to descriptions in terms of the
full $N$-body distribution, starting from exact solutions of one-dimensional
models, using a Matrix Product Ansatz method when correlations are present.
Since exactly solvable models are scarce, we also present some approximation
methods that can be used to determine the $N$-body distribution in a large
system of dissipative units. These methods include the Edwards approach for
dense granular matter and the approximate treatment of multiparticle Langevin
equations with coloured noise, which models systems of self-propelled
particles. Throughout this review, emphasis is put on methodological aspects of
the statistical modeling and on formal similarities between different physical
problems, rather than on the specific behaviour of a given system.


title:
The number of ideals of $\mathbb{Z}[x]$ containing
  $x(x-\alpha)(x-\beta)$ with given index

abstract:
  It is well-known that a connected regular graph is strongly-regular if and
only if its adjacency matrix has exactly three eigenvalues. Let $B$ denote an
integral square matrix and $\langle B \rangle$ denote the subring of the full
matrix ring generated by $B$. Then $\langle B \rangle$ is a free
$\mathbb{Z}$-module of finite rank, which guarantees that there are only
finitely many ideals of $\langle B \rangle$ with given finite index. Thus, the
formal Dirichlet series $\zeta_{\langle B \rangle}(s)=\sum_{n\geq 1}a_n n^{-s}$
is well-defined where $a_n$ is the number of ideals of $\langle B \rangle$ with
index $n$. In this article we aim to find an explicit form of $\zeta_{\langle B
\rangle}(s)$ when $B$ has exactly three eigenvalues all of which are integral,
e.g., the adjacency matrix of a strongly-regular graph which is not a
conference graph with a non-squared number of vertices. By isomorphism theorem
for rings, $\langle B \rangle$ is isomorphic to
$\mathbb{Z}[x]/m(x)\mathbb{Z}[x]$ where $m(x)$ is the minimal polynomial of $B$
over $\mathbb{Q}$, and $\mathbb{Z}[x]/m(x)\mathbb{Z}[x]$ is isomorphic to
$\mathbb{Z}[x]/m(x+\gamma)\mathbb{Z}[x]$ for each $\gamma\in \mathbb{Z}$. Thus,
the problem is reduced to counting the number of ideals of
$\mathbb{Z}[x]/x(x-\alpha)(x-\beta)\mathbb{Z}[x]$ with given finite index where
$0,\alpha$ and $\beta$ are distinct integers.


title:
Generalised balance equations for charged particle transport via
  localised and delocalised states: Mobility, generalised Einstein relations
  and fractional transport

abstract:
  A generalised phase-space kinetic Boltzmann equation for highly
non-equilibrium charged particle transport via localised and delocalised states
is used to develop continuity, momentum and energy balance equations,
accounting explicitly for scattering, trapping/detrapping and recombination
loss processes. Analytic expressions detail the effect of these microscopic
processes on the mobility and diffusivity. Generalised Einstein relations (GER)
are developed that enable the anisotropic nature of diffusion to be determined
in terms of the measured field-dependence of the mobility. Interesting
phenomena such as negative differential conductivity and recombination
heating/cooling are shown to arise from recombination loss processes and the
localised and delocalised nature of transport. Fractional transport emerges
naturally within this framework through the appropriate choice of divergent
mean waiting time distributions for localised states, and fractional
generalisations of the GER and mobility are presented. Signature impacts on
time-of-flight current transients of recombination loss processes via both
localised and delocalised states are presented.


title: Towards a link theoretic characterization of smoothness

abstract:
  A theorem of Mumford states that, on complex surfaces, any normal isolated
singularity whose link is diffeomorphic to a sphere is actually a smooth point.
While this property fails in higher dimensions, McLean asks whether the contact
structure that the link inherits from its embedding in the variety may suffice
to characterize smooth points among normal isolated singularities. He proves
that this is the case in dimension 3. In this paper, we use techniques from
birational geometry to extend McLean's result to a large class of higher
dimensional singularities. We also introduce a more refined invariant of the
link using CR geometry, and conjecture that this invariant is strong enough to
characterize smoothness in full generality.


title: Integrable Cosmological Potentials

abstract:
  The problem of classification of the Einstein--Friedman cosmological
Hamiltonians $H$ with a single scalar inflaton field $\varphi$ that possess an
additional integral of motion polynomial in momenta on the shell of the
Friedman constraint $H=0$ is considered. Necessary and sufficient conditions
for the existence of first, second, and third degree integrals are derived.
These conditions have the form of ODEs for the cosmological potential
$V(\varphi)$. In the case of linear and quadratic integrals we find general
solutions of the ODEs and construct the corresponding integrals explicitly. A
new wide class of Hamiltonians that possess a cubic integral is derived. The
corresponding potentials are represented in a parametric form in terms of the
associated Legendre functions. Six families of special elementary solutions are
described and sporadic superintegrable cases are discussed.

categories: hep-th astro-ph.CO gr-qc math-ph math.MP nlin.SI


title: Active cloaking for clusters of pins in thin plates

abstract:
  This paper considers active cloaking of a square array of evenly spaced pins
in a Kirchhoff plate in the presence of flexural waves. Active sources are
distributed exterior to the cluster and are represented by the non-singular
Green's function for the biharmonic operator. The complex amplitudes of the
active sources, which cancel out selected multipole orders of the scattered
field, are found by solving an algebraic system of equations. For frequencies
in the zero-frequency stop band, we find that a small number of active sources
located on a grid is sufficient for cloaking. For higher frequencies, we
achieve efficient cloaking with the active sources positioned on a circle
surrounding the cluster. We demonstrate the cloaking efficiency with several
numerical illustrations, considering key frequencies from band diagrams and
dispersion surfaces for a Kirchhoff plate pinned in a doubly periodic fashion.


title:
An efficient semi-implicit solver for direct numerical simulation of
  compressible flows at all speeds

abstract:
  We develop a semi-implicit algorithm for time-accurate simulation of the
compressible Navier-Stokes equations, with special reference to wall-bounded
flows. The method is based on linearization of the partial convective fluxes
associated with acoustic waves, in such a way to suppress, or at least mitigate
the acoustic time step limitation. Together with replacement of the total
energy equation with the entropy transport equation, this approach avoids the
inversion of block-banded matrices involved in classical methods, which is
replaced by less demanding inversion of standard banded matrices. The method is
extended to deal with implicit integration of viscous terms and to multiple
space dimensions through approximate factorization, and used as a building
block of third-order Runge-Kutta time stepping scheme. Numerical experiments
are carried out for isotropic turbulence, plane channel flow, and flow in a
square duct. All available data support higher computational efficiency than
existing methods, and saving of resources ranging from $85\%$ under
low-subsonic flow conditions, to about $50\%$ in supersonic flow.


title:
Functorial filtrations for homotopy categories of some generalisations
  of gentle algebras

abstract:
  We consider algebras defined over a complete, local and noetherian ground
ring. They are gentle algebras in case the ground ring is a field. The
unbounded homotopy category of complexes of projective modules is considered.
Complexes with finitely-generated homogeneous components are shown to be
isomorphic to direct sums of indecomposable string and band complexes. The
corresponding isoclasses are described, and the Krull-Remak-Schmidt-Azumaya
property is verified. This classification problem is solved using the idea of
functorial filtrations.


title: Language Detection For Short Text Messages In Social Media

abstract:
  With the constant growth of the World Wide Web and the number of documents in
different languages accordingly, the need for reliable language detection tools
has increased as well. Platforms such as Twitter with predominantly short texts
are becoming important information resources, which additionally imposes the
need for short texts language detection algorithms. In this paper, we show how
incorporating personalized user-specific information into the language
detection algorithm leads to an important improvement of detection results. To
choose the best algorithm for language detection for short text messages, we
investigate several machine learning approaches. These approaches include the
use of the well-known classifiers such as SVM and logistic regression, a
dictionary based approach, and a probabilistic model based on modified
Kneser-Ney smoothing. Furthermore, the extension of the probabilistic model to
include additional user-specific information such as evidence accumulation per
user and user interface language is explored, with the goal of improving the
classification performance. The proposed approaches are evaluated on randomly
collected Twitter data containing Latin as well as non-Latin alphabet languages
and the quality of the obtained results is compared, followed by the selection
of the best performing algorithm. This algorithm is then evaluated against two
already existing general language detection tools: Chromium Compact Language
Detector 2 (CLD2) and langid, where our method significantly outperforms the
results achieved by both of the mentioned methods. Additionally, a preview of
benefits and possible applications of having a reliable language detection
algorithm is given.


title: An approach to directly probe simultaneity

abstract:
  The theory of special relativity derives from the Lorentz transformation. The
Lorentz transformation implies differential simultaneity and light speed
isotropy. Experiments to probe differential simultaneity should be able to
distinguish the Lorentz transformation from a kinematically-similar alternate
transformation that predicts absolute simultaneity, the absolute Lorentz
transformation. Here, we describe how published optical tests of light speed
isotropy/anisotropy cannot distinguish between the two transformations. We show
that the shared equations of the two transformations, from the perspective of
the "stationary" observer, are sufficient to predict null results in optical
resonator experiments and in tests of frequency changes in one-way light paths.
In an influential 1910 exposition on differential simultaneity, Comstock
described how a "stationary" observer would observe different clock readings
for spatially-separated "moving" clocks. The difference in clock readings is an
integral aspect of differential simultaneity. We derive the equation for the
difference in clock readings and show that it is equivalent to the Sagnac
correction that describes light speed anisotropies in satellite communications.
We describe an experimental strategy that can measure the differences in
spatially-separated clock times to allow a direct probe of the nature of
simultaneity.


title:
Empirically Grounded Agent-Based Models of Innovation Diffusion: A
  Critical Review

abstract:
  Innovation diffusion has been studied extensively in a variety of
disciplines, including sociology, economics, marketing, ecology, and computer
science. Traditional literature on innovation diffusion has been dominated by
models of aggregate behavior and trends. However, the agent-based modeling
(ABM) paradigm is gaining popularity as it captures agent heterogeneity and
enables fine-grained modeling of interactions mediated by social and geographic
networks. While most ABM work on innovation diffusion is theoretical,
empirically grounded models are increasingly important, particularly in guiding
policy decisions. We present a critical review of empirically grounded
agent-based models of innovation diffusion, developing a categorization of this
research based on types of agent models as well as applications. By connecting
the modeling methodologies in the fields of information and innovation
diffusion, we suggest that the maximum likelihood estimation framework widely
used in the former is a promising paradigm for calibration of agent-based
models for innovation diffusion. Although many advances have been made to
standardize ABM methodology, we identify four major issues in model calibration
and validation, and suggest potential solutions.


title: Spreading and vanishing in a West Nile virus model with expanding fronts

abstract:
  In this paper, we study a simplified version of a West Nile virus model
discussed by Lewis et al. [28], which was considered as a first approximation
for the spatial spread of WNv. The basic reproduction number $R_0$ for the
non-spatial epidemic model is defined and a threshold parameter $R_0 ^D$ for
the corresponding problem with null Dirichlet boundary condition is introduced.
We consider a free boundary problem with coupled system, which describes the
diffusion of birds by a PDE and the movement of mosquitoes by a ODE. The risk
index $R_0^F (t)$ associated with the disease in spatial setting is
represented. Sufficient conditions for the WNv to eradicate or to spread are
given. The asymptotic behavior of the solution to system when the spreading
occurs are considered. It is shown that the initial number of infected
populations, the diffusion rate of birds and the length of initial habitat
exhibit important impacts on the vanishing or spreading of the virus. Numerical
simulations are presented to illustrate the analytical results.


title:
Obtaining nonvanishing $\theta_{13}$ with constrained neutrino Yukawa
  matrix and implications for flavor model buildings

abstract:
  Assuming a diagonal Majorana neutrino mass matrix, we investigate the
neutrino Yukawa textures which lead to a non-zero reactor mixing angle
$\theta_{13}$. The neutrino effective coupling matrix $\kappa^{eff}$ is
pre-diagonalized by a constant mixing pattern $V_{\nu}$ with a vanishing
$\theta^{\nu}_{13}$. The resulting pre-diagonal symmetrical matrix $\kappa$ is
set to be four texture zeros with two types of off-diagonal elements nonzero,
which is $\kappa_{13}$ and $\kappa_{23}$, respectively. With the expectation of
simple textures we thoroughly classify the linear combinations, $\alpha_{i}$,
$\beta_{i}$ and $\gamma_{i}$ of Yukawa elements $\lambda_{ij}$ in a same row,
according to the values vanishing or not. Each set of the classifications can
lead to a Yukawa texture which may have implications for the discrete flavor
model buildings. We also present a model based on $A_{4}$ according to one set
of the constraints on the three combinations with a specific choice of a
coefficient in Yukawa texture.


title:
Parametric Presburger arithmetic: logic, combinatorics, and
  quasi-polynomial behavior

abstract:
  Parametric Presburger arithmetic concerns families of sets S_t in Z^d, for t
in N, that are defined using addition, inequalities, constants in Z, Boolean
operations, multiplication by t, and quantifiers on variables ranging over Z.
That is, such families are defined using quantifiers and Boolean combinations
of formulas of the form a(t) x <= b(t), where a(t) is in Z[t]^d, b(t) in Z[t].
A function g: N -> Z is a quasi-polynomial if there exists a period m and
polynomials f_0, ..., f_{m-1} in Q[t] such that g(t)=f_i(t) for t congruent to
i (mod m.)
  Recent results of Chen, Li, Sam; Calegari, Walker; Roune, Woods; and Shen
concern specific families in parametric Presburger arithmetic that exhibit
quasi-polynomial behavior. For example, S_t might be an a quasi-polynomial
function of t or an element x(t) in S_t might be specifiable as a function with
quasi-polynomial coordinates, for sufficiently large t. Woods conjectured that
all parametric Presburger sets exhibit this quasi-polynomial behavior. Here, we
prove this conjecture, using various tools from logic and combinatorics.


title: Profitable Task Allocation in Mobile Cloud Computing

abstract:
  We propose a game theoretic framework for task allocation in mobile cloud
computing that corresponds to offloading of compute tasks to a group of nearby
mobile devices. Specifically, in our framework, a distributor node holds a
multidimensional auction for allocating the tasks of a job among nearby mobile
nodes based on their computational capabilities and also the cost of
computation at these nodes, with the goal of reducing the overall job
completion time. Our proposed auction also has the desired incentive
compatibility property that ensures that mobile devices truthfully reveal their
capabilities and costs and that those devices benefit from the task allocation.
To deal with node mobility, we perform multiple auctions over adaptive time
intervals. We develop a heuristic approach to dynamically find the best time
intervals between auctions to minimize unnecessary auctions and the
accompanying overheads. We evaluate our framework and methods using both real
world and synthetic mobility traces. Our evaluation results show that our game
theoretic framework improves the job completion time by a factor of 2-5 in
comparison to the time taken for executing the job locally, while minimizing
the number of auctions and the accompanying overheads. Our approach is also
profitable for the nearby nodes that execute the distributor's tasks with these
nodes receiving a compensation higher than their actual costs.


title: A Distributed Multilevel Force-directed Algorithm

abstract:
  The wide availability of powerful and inexpensive cloud computing services
naturally motivates the study of distributed graph layout algorithms, able to
scale to very large graphs. Nowadays, to process Big Data, companies are
increasingly relying on PaaS infrastructures rather than buying and maintaining
complex and expensive hardware. So far, only a few examples of basic
force-directed algorithms that work in a distributed environment have been
described. Instead, the design of a distributed multilevel force-directed
algorithm is a much more challenging task, not yet addressed. We present the
first multilevel force-directed algorithm based on a distributed vertex-centric
paradigm, and its implementation on Giraph, a popular platform for distributed
graph algorithms. Experiments show the effectiveness and the scalability of the
approach. Using an inexpensive cloud computing service of Amazon, we draw
graphs with ten million edges in about 60 minutes.


title:
Search for $\Theta^+(1540)$ emission in hadron--nucleus collisions at
  400--700 GeV

abstract:
  The data on hadron--nucleus collisions at 400--700 GeV, collected by the
SELEX experiment at Fermilab, are analyzed for formation of the exotic
pentaquark baryon $\Theta^+(1540)$. A narrow enhancement near 1539 MeV is
observed in the mass spectrum of the $pK^0_S$ system emitted at small $x_F$
from hadron collisions with copper nuclei. The statistical significance of the
peak is near 9 standard deviations. Fitted width of the observed $pK^0_S$
resonance is consistent with being entirely due to experimental resolution, and
its intrinsic width is restricted to $\Gamma < 3$ MeV at 90\% CL. The data
favor positive rather than negative strangeness for the $pK^0_S$ resonance
observed in $h$Cu collisions. At the same time, the $pK^0_S$ mass spectrum for
collisions in carbon is featureless. The yield of $\Theta^+$ baryons per $h$C
collision is restricted to be $< 24$\% of the yield per $h$Cu collision.


title: Formation of plasma around a small meteoroid: 1. Kinetic theory

abstract:
  Every second millions of small meteoroids enter the Earth's atmosphere
producing dense plasmas. Radars easily detect these plasmas and researchers use
this data to characterize both the meteoroids and the atmosphere. This paper
develops a first-principle kinetic theory describing the behavior of particles,
ablated from a fast-moving meteoroid, that colliside with the atmospheric
molecules. This theory produces analytic expressions describing the spatial
structure and velocity distributions of ions and neutrals near the ablating
meteoroid. This analytical model will serve as a basis for a more accurate
quantitative interpretation of radar measurements and should help calculate
meteoroid and atmosphere parameters from radar head-echo observations.


title: On magnetic fields of radio pulsars

abstract:
  We used the magneto-dipole radiation mechanism for the braking of radio
pulsars to calculate the new values of magnetic inductions at the surfaces of
neutron stars. For this aim we estimated the angles ? between the rotation axis
and the magnetic moment of the neutron star for 376 radio pulsars using three
different methods. It was shown that there was the predominance of small
inclinations of the magnetic axes. Using the obtained values of the angle ? we
calculated the equatorial magnetic inductions for pulsars considered. These
inductions are several times higher as a rule than corresponding values in the
known catalogs.


title: Multi-Person Pose Estimation with Local Joint-to-Person Associations

abstract:
  Despite of the recent success of neural networks for human pose estimation,
current approaches are limited to pose estimation of a single person and cannot
handle humans in groups or crowds. In this work, we propose a method that
estimates the poses of multiple persons in an image in which a person can be
occluded by another person or might be truncated. To this end, we consider
multi-person pose estimation as a joint-to-person association problem. We
construct a fully connected graph from a set of detected joint candidates in an
image and resolve the joint-to-person association and outlier detection using
integer linear programming. Since solving joint-to-person association jointly
for all persons in an image is an NP-hard problem and even approximations are
expensive, we solve the problem locally for each person. On the challenging
MPII Human Pose Dataset for multiple persons, our approach achieves the
accuracy of a state-of-the-art method, but it is 6,000 to 19,000 times faster.


title: The $(h,k)$-Server Problem on Bounded Depth Trees

abstract:
  We study the $k$-server problem in the resource augmentation setting i.e.,
when the performance of the online algorithm with $k$ servers is compared to
the offline optimal solution with $h \leq k$ servers. The problem is very
poorly understood beyond uniform metrics. For this special case, the classic
$k$-server algorithms are roughly $(1+1/\epsilon)$-competitive when
$k=(1+\epsilon) h$, for any $\epsilon >0$. Surprisingly however, no
$o(h)$-competitive algorithm is known even for HSTs of depth 2 and even when
$k/h$ is arbitrarily large.
  We obtain several new results for the problem. First we show that the known
$k$-server algorithms do not work even on very simple metrics. In particular,
the Double Coverage algorithm has competitive ratio $\Omega(h)$ irrespective of
the value of $k$, even for depth-2 HSTs. Similarly the Work Function Algorithm,
that is believed to be optimal for all metric spaces when $k=h$, has
competitive ratio $\Omega(h)$ on depth-3 HSTs even if $k=2h$. Our main result
is a new algorithm that is $O(1)$-competitive for constant depth trees,
whenever $k =(1+\epsilon )h$ for any $\epsilon > 0$. Finally, we give a general
lower bound that any deterministic online algorithm has competitive ratio at
least 2.4 even for depth-2 HSTs and when $k/h$ is arbitrarily large. This gives
a surprising qualitative separation between uniform metrics and depth-2 HSTs
for the $(h,k)$-server problem, and gives the strongest known lower bound for
the problem on general metrics.


title: An extension of Wilf's conjecture to affine semigroups

abstract:
  Let $\CaC\subset \Q^p$ be a rational cone. An affine semigroup $S\subset
\CaC$ is a $\CaC$-semigroup whenever $(\CaC\setminus S)\cap \N^p$ has only a
finite number of elements.
  In this work, we study the tree of $\CaC$-semigroups, give a method to
generate it and study their subsemigroups with minimal embedding dimension. We
extend Wilf's conjecture for numerical semigroups to $\CaC$-semigroups and give
some families of $\CaC$-semigroups fulfilling the extended conjecture. We also
check that other conjectures on numerical semigroups seem to be also satisfied
by $\CaC$-semigroups.


title: Some Qi-type integral inequalities involving several weight functions

abstract:
  We prove some integral inequalities related to Feng Qi's inequality (2000)
and obtain a few corollaries.


title:
Gaussian regression and power spectral density estimation with missing
  data: The MICROSCOPE space mission as a case study

abstract:
  We present a Gaussian regression method for time series with missing data and
stationary residuals of unknown power spectral density (PSD). The missing data
are efficiently estimated by their conditional expectation as in universal
Kriging, based on the circulant approximation of the complete data covariance.
After initialization with an autoregessive fit of the noise, a few iterations
of estimation/reconstruction steps are performed until convergence of the
regression and PSD estimates, in a way similar to the
expectation-conditional-maximization algorithm. The estimation can be performed
for an arbitrary PSD provided that it is sufficiently smooth. The algorithm is
developed in the framework of the MICROSCOPE space mission whose goal is to
test the weak equivalence principle (WEP) with a precision of $10^{-15}$. We
show by numerical simulations that the developed method allows us to meet three
major requirements: to maintain the targeted precision of the WEP test in spite
of the loss of data, to calculate a reliable estimate of this precision and of
the noise level, and finally to provide consistent and faithful reconstructed
data to the scientific community.


title: Blackhole evaporation model without information loss

abstract:
  A simple model of a blackhole evaporation without information loss is given.
In this model, the blackhole is \textit{not} in a specific mass eigenstate as
it evaporates but rather, is in a superposition of various mass eigenstates and
is entangled with the radiation. For astrophysical blackhole, the mass
distribution is sharply peak about its average value with a vanishingly small
standard deviation, which is consistent with our intuition of a classical
object. It is then shown that as the blackhole evaporates, the evolution of the
closed blackhole-radiation system is unitary. This is done by showing that the
full density matrix satisfies Tr$\rho^2=1$ at all times. Finally, it is shown
that the entanglement entropy, after an initial increase, decreases and
approaches zero. These show that this model of blackhole evaporation has no
infromation loss.


title:
Geometry of historical epoch, the Alexandrov's problem and non-G\"odel
  quantum time machine

abstract:
  The new quantum principle of a time machine that is not using a smooth
timelike loops in Lorentz manifolds is described. The proposed time machine is
based on the destruction of interference of quantum superposition states in the
Wheeler superspace.


title: A combinatorial model for the known Bousfield classes

abstract:
  We give a combinatorial construction of an ordered semiring A, and show that
it can be identified with a certain subquotient of the semiring of p-local
Bousfield classes, containing almost all of the classes that have previously
been named and studied. This is a convenient way to encapsulate most of the
known results about Bousfield classes.


title: Fractional differential and integral operations and cumulative processes

abstract:
  In this study the general formula for differential and integral operations of
fractional calculus via fractal operators by the method of cumulative
diminution and cumulative growth is obtained. The under lying mechanism in the
success of traditional fractional calculus for describing complex systems is
uncovered. The connection between complex physics with fractional
differentiation and integration operations is established.


title:
Ordering properties of sample minimum from Kumaraswamy-G random
  variables

abstract:
  In this paper we compare the minimums of two independent and heterogeneous
samples each following Kumaraswamy-G distribution with the same and the
different parent distribution functions. The comparisons are carried out with
respect to usual stochastic ordering and hazard rate ordering with majorized
shape parameters of the distributions. The likelihood ratio ordering between
the minimum order statistics is established for heterogeneous multiple outlier
Kumaraswamy-G random variables with the same parent distribution function


title: Colliding interstellar bubbles in the direction of l=54{\deg}

abstract:
  Interstellar bubbles are structures in the interstellar medium with diameters
of a few to tens of parsecs. Their progenitors are stellar winds, intense
radiation of massive stars, or supernova explosions. Star formation and young
stellar objects are commonly associated with these structures. We compare IR
observations of bubbles N115, N116 and N117 with atomic, molecular and ionized
gas in this region. While determining the dynamical properties of the bubbles,
we also look into their ambient environment to understand their formation in a
wider context. For finding bubbles in HI (VLA Galactic Plane Survey) and CO
data (Galactic Ring Survey), we used their images from Galactic Legacy Infrared
Mid-Plane Survey. We manually constructed masks based on the appearance of the
bubbles in the IR images and applied it to the HI and CO data. We determined
their kinematic distance, size, expansion velocity, mass, original density of
the maternal cloud, age and energy input. We identified two systems of bubbles:
the first, background system, is formed by large structures G053.9+0.2 and SNR
G054.4-0.3 and the infrared bubble N116+117. The second, foreground system,
includes the infrared bubble N115 and two large HI bubbles, which we discovered
in the HI data. Both systems are independent, lying at different distances, but
look similar. They are both formed by two large colliding bubbles with radii
around 20-30 pc and ages of a few million years. A younger and smaller (~4 pc,
less than a million years) infrared bubble lies at the position of the
collision. We found that both infrared bubbles N115 and N116+117 are associated
with the collisions of larger and older bubbles. We propose, that such
collisions increase the probability of further star formation, probably by
squeezing the interstellar material, suggesting that it is an important
mechanism for star formation.


title: Quantum speed limit time in a magnetic resonance

abstract:
  A visualization for dynamics of a qudit spin vector in a time-dependent
magnetic field is realized by means of mapping a solution for a spin vector on
the three-dimensional spherical curve (vector hodograph). The obtained results
obviously display the quantum interference of precessional and nutational
effects on the spin vector in the magnetic resonance. For any spin the bottom
bounds of the quantum speed limit time (QSL) are found. It is shown that the
bottom bound goes down when using multilevel spin systems. Under certain
conditions the non-nil minimal time, which is necessary to achieve the
orthogonal state from the initial one, is attained at spin S=2. An estimation
of the product of two and three standard deviations of the spin components are
presented. We discuss the dynamics of the mutual uncertainty, conditional
uncertainty and conditional variance in terms of spin standard deviations. The
study can find practical applications in the magnetic resonance, 3D
visualization of computational data and in designing of optimized information
processing devices for quantum computation and communication.


title: Low Ply Drawings of Trees

abstract:
  We consider the recently introduced model of \emph{low ply graph drawing}, in
which the ply-disks of the vertices do not have many common overlaps, which
results in a good distribution of the vertices in the plane. The
\emph{ply-disk} of a vertex in a straight-line drawing is the disk centered at
it whose radius is half the length of its longest incident edge. The largest
number of ply-disks having a common overlap is called the \emph{ply-number} of
the drawing.
  We focus on trees. We first consider drawings of trees with constant
ply-number, proving that they may require exponential area, even for stars, and
that they may not even exist for bounded-degree trees. Then, we turn our
attention to drawings with logarithmic ply-number and show that trees with
maximum degree $6$ always admit such drawings in polynomial area.


title:
A PSF-based approach to Kepler/K2 data - III. Search for exoplanets and
  variable stars within the open cluster M 67 (NGC 2682)

abstract:
  In the third paper of this series we continue the exploitation of Kepler/K2
data in dense stellar fields using our PSF-based method. This work is focused
on a ~720-arcmin^2 region centred on the Solar-metallicity and Solar-age open
cluster M 67. We extracted light curves for all detectable sources in the
Kepler channels 13 and 14, adopting our technique based on the usage of a
high-angular-resolution input catalogue and target-neighbour subtraction. We
detrended light curves for systematic errors, and searched for variables and
exoplanets using several tools. We found 451 variables, of which 299 are new
detection. Three planetary candidates were detected by our pipeline in this
field. Raw and detrended light curves, catalogues, and K2 stacked images used
in this work will be released to the community.


title:
Continuum elastic model of fullerenes and the sphericity of the carbon
  onion shells

abstract:
  A continuum elastic model of fullerenes is presented by utilizing the analogy
between the closed carbon cages and elastic shells. We derive expressions for
the curvature related strain energies Ep of the pentagonal protrusions. We
propose to explain the observed sphericity of the carbon onions shells as
opposed to the predicted protrusions around the pentagonal defects on the basis
of our continuum elastic model of fullerenes. In our model the energy inherent
in the pentagonal protrusions Ep is due to the stretching and bending of the
shell and shown to be a function of the structural parameters. It also defines
the upper limit on the size of the free-standing fullerenes. Using Ep and the
topological arguments, we show that the pentagonal protrusions will be smoothed
out, resulting in spherical shells of the carbon onions denoted as
C60@C240@C540@C960@C1500 ,... .


title:
Constrained similarity of 2-D trajectories by minimizing the H1
  semi-norm of the trajectory difference

abstract:
  This paper defines constrained functional similarity between 2-D trajectories
via minimizing the H1 semi-norm of the difference between the trajectories. An
exact general solution is obtained for the case wherein the components of the
trajectories are mesh-functions defined on a uniform mesh and the imposed
constraints are linear. Various examples are presented, one of which features
application to mechanics and two-point boundary value problems. A MATLAB code
is given for the solution of one of the examples. The code could easily be
adjusted to other cases.


title:
Design and Characterisation of Tissue-Mimicking Gel Phantoms for
  Diffusion Kurtosis Imaging

abstract:
  Purpose: The aim of this work was to create tissue-mimicking gel phantoms
appropriate for diffusion kurtosis imaging (DKI) for quality assurance,
protocol optimization and sequence development.
  Methods: A range of agar, agarose and polyvinyl alcohol phantoms with
concentrations ranging from 1.0% to 3.5%, 0.5% to 3.0% and 10% to 20%,
respectively, and up to 3 g of glass microspheres per 100 ml were created.
Diffusion coefficients, excess kurtosis values and relaxation rates were
experimentally determined.
  Results: The kurtosis values for the plain gels ranged from 0.05 with 95%
confidence interval (CI) of $(0.029, 0.071)$ to $0.216(0.185, 0.246)$, well
below the kurtosis values reported in the literature for various tissues. The
addition of glass microspheres increased the kurtosis of the gels with values
up to $0.523(0.465, 0.581)$ observed for gels with the highest concentration of
microspheres. Repeat scans of some of the gels after more than six months of
storage at room temperature indicate changes in the diffusion parameters of
less than 10%. The addition of the glass microspheres reduces the apparent
diffusion coefficients (ADCs) and increases the longitudinal and transverse
relaxation rates but the values remain comparable to those for plain gels and
tissue, with ADCs observed ranging from $818(585, 1053) \times 10^{-6}$
mm$^2$/s to $2257(2118, 2296) \times 10^{-6}$ mm$^2$/s, and R1 values ranging
from $0.34(0.32, 0.35)$ 1/s to $0.51(0.50, 0.52)$ 1/s, and R2 values ranging
from $9.69(9.34, 10.04)$ 1/s to $33.07(27.10, 39.04)$ 1/s.
  Conclusions: Glass microspheres can be used to effectively modify diffusion
properties of gel phantoms and achieve a range of kurtosis values comparable to
those reported for a variety of tissues.