title: Coins falling in water

abstract:
  When a coin falls in water, its trajectory is one of four types determined by
its dimensionless moment of inertia $I^\ast$ and Reynolds number Re: (A)
steady; (B) fluttering; (C) chaotic; or (D) tumbling. The dynamics induced by
the interaction of the water with the surface of the coin, however, makes the
exact landing site difficult to predict a priori. Here, we describe a carefully
designed experiment in which a coin is dropped repeatedly in water, so that we
can determine the probability density functions (pdf) associated with the
landing positions for each of the four trajectory types, all of which are
radially symmetric about the center-drop line. In the case of the steady mode,
the pdf is approximately Gaussian distributed, with variances that are small,
indicating that the coin is most likely to land at the center, right below the
point it is dropped from. For the other falling modes, the center is one of the
least likely landing sites. Indeed, the pdf's of the fluttering, chaotic and
tumbling modes are characterized by a "dip" around the center. For the tumbling
mode, the pdf is a ring configuration about the center-line, with a ring width
that depends on the dimensionless parameters $I^\ast$ and Re and height from
which the coin is dropped. For the chaotic mode, the pdf is generally a
broadband distribution spread out radially symmetrically about the center-line.
For the steady and fluttering modes, the coin never flips, so the coin lands
with the same side up as was dropped. For the chaotic mode, the probability of
heads or tails is close to 0.5. In the case of the tumbling mode, the
probability of heads or tails based on the height of the drop which determines
whether the coin flips an even or odd number of times during descent.


title: Thick Dirac-Nambu-Goto branes on black hole backgrounds

abstract:
  Thickness corrections to static, axisymmetric Dirac-Nambu-Goto branes
embedded into spherically symmetric black hole spacetimes with arbitrary number
of dimensions are studied. First, by applying a perturbative approximation, it
is found that the thick solutions deviate significantly in their analytic
properties from the thin ones near the axis of the system, and perturbative
approaches around the thin configurations can not provide regular thick
solutions above a certain dimension. For the general case, a non-perturbative,
numerical approach is applied and regular solutions are obtained for arbitrary
brane and bulk dimensions. As a special case, it has been found that
2-dimensional branes are exceptional, as they share their analytic properties
with the thin branes rather than the thick solutions of all other dimensions.


title:
Conformal inversion and Maxwell field invariants in four- and
  six-dimensional spacetimes

abstract:
  Conformally compactified (3+1)-dimensional Minkowski spacetime may be
identified with the projective light cone in (4+2)-dimensional spacetime. In
the latter spacetime the special conformal group acts via rotations and boosts,
and conformal inversion acts via reflection in a single coordinate.
Hexaspherical coordinates facilitate dimensional reduction of Maxwell
electromagnetic field strength tensors to (3+1) from (4 + 2) dimensions. Here
we focus on the operation of conformal inversion in different
coordinatizations, and write some useful equations. We then write a conformal
invariant and a pseudo-invariant in terms of field strengths; the
pseudo-invariant in (4+2) dimensions takes a new form. Our results advance the
study of general nonlinear conformal-invariant electrodynamics based on
nonlinear constitutive equations.


title:
Small-time asymptotics for a general local-stochastic volatility model
  with a jump-to-default: curvature and the heat kernel expansion

abstract:
  We compute a sharp small-time estimate for implied volatility under a general
uncorrelated local-stochastic volatility model. For this we use the Bellaiche
\cite{Bel81} heat kernel expansion combined with Laplace's method to integrate
over the volatility variable on a compact set, and (after a gauge
transformation) we use the Davies \cite{Dav88} upper bound for the heat kernel
on a manifold with bounded Ricci curvature to deal with the tail integrals. If
the correlation $\rho < 0$, our approach still works if the drift of the
volatility takes a specific functional form and there is no local volatility
component, and our results include the SABR model for $\beta=1, \rho \le 0$.
\bl{For uncorrelated stochastic volatility models, our results also include a
SABR-type model with $\beta=1$ and an affine mean-reverting drift, and the
exponential Ornstein-Uhlenbeck model.} We later augment the model with a single
jump-to-default with intensity $\lm$, which produces qualitatively different
behaviour for the short-maturity smile; in particular, for $\rho=0$,
log-moneyness $x > 0$, the implied volatility increases by $\lm f(x) t +o(t) $
for some function $f(x)$ which blows up as $x \searrow 0$. Finally, we compare
our result with the general asymptotic expansion in Lorig, Pagliarani \&
Pascucci \cite{LPP15}, and we verify our results numerically for the SABR model
using Monte Carlo simulation and the exact closed-form solution given in
Antonov \& Spector \cite{AS12} for the case $\rho=0$.


title: R\"over's Simple Group is of Type $F_\infty$

abstract:
  We prove that Claas R\"over's Thompson-Grigorchuk simple group $V\mathcal{G}$
has type $F_\infty$. The proof involves constructing two complexes on which
$V\mathcal{G}$ acts: a simplicial complex analogous to the Stein complex for
$V$, and a polysimiplical complex analogous to the Farley complex for $V$. We
then analyze the descending links of the polysimplicial complex, using a
theorem of Belk and Forrest to prove increasing connectivity.


title: Non-Real Zero Decreasing Operators Related to Orthogonal Polynomials

abstract:
  Laguerre's theorem regarding the number of non-real zeros of a polynomial and
its image under certain linear operators is generalized. This generalization is
then used to (1) exhibit a number of previously undiscovered complex zero
decreasing sequences for the Chebyshev, Legendre, and generalized Laguerre
polynomial bases and (2) simultaneously generate a basis $B$ and a
corresponding $B$-CZDS. Some extensions to transcendental entire functions in
the Laguerre-Polya class are given which, in turn, give a new and short proof
of a previously known result due to one of the authors. The paper concludes
with several open questions.


title: Gravitational Waves from Preheating in M-flation

abstract:
  Matrix inflation, or M-flation, is a string theory motivated inflationary
model with three scalar field matrices and gauge fields in the adjoint
representation of the $\mathbf{U}(N)$ gauge group. One of these $3N^2$ scalars
appears as the effective inflaton while the rest of the fields (scalar and
gauge fields) can play the role of isocurvature fields during inflation and
preheat fields afterwards. There is a region in parameter space and initial
field values, "the hilltop region," where predictions of the model are quite
compatible with the recent Planck data. We show that in this hilltop region, if
the inflaton ends up in the supersymmetric vacuum, the model can have an
embedded preheating mechanism. Couplings of the preheat modes are related to
the inflaton self-couplings and therefore are known from the CMB data. Through
lattice simulations performed using a symplectic integrator, we numerically
compute the power spectra of gravitational waves produced during the preheating
stage following M-flation. The preliminary numerical simulation of the spectrum
from multi-preheat fields peaks in the GHz band with an amplitude
$\Omega_{\mathrm{gw}}h^{2} \propto 10^{-16}$, suggesting that the model has
concrete predictions for the ultra-high frequency gravity-wave probes. This
signature could be used to distinguish the model from rival inflationary models


title: Thermalization and isotropization in heavy-ion collisions

abstract:
  I review our current understanding of the processes driving the
thermalization and isotropization of the quark gluon plasma (QGP) created in
ultrarelativistic heavy ion collisions (URHICs). I begin by discussing the
phenomenological evidence in favor of the creation of a thermal but
momentum-space anisotropic QGP in URHICs. I then discuss the degree of
isotropization using viscous (dissipative) hydrodynamics, weak-coupling
approaches to QGP dynamics, and strong-coupling approaches to QGP dynamics.
Finally, I report on recent progress in the area of real-time non-abelian gauge
field simulations and non-abelian Boltzmann-Vlasov-based hard-loop simulations.


title: Discriminatory proofreading regimes in non-equilibrium systems

abstract:
  We use ideas from kinetic proofreading, an error-correcting mechanism in
biology, to identify new kinetic regimes in non-equilibrium systems. These
regimes are defined by the sensitivity of the occupancy of a state of the
system to a change in its energy. In biological contexts, higher sensitivity
corresponds to stronger discrimination between molecular substrates with
different energetics competing in the same reaction. We study this
discriminatory ability in systems with discrete states that are connected by a
general network of transitions. We find multiple regimes of different
discriminatory ability when the energy of a given state of the network is
varied. Interestingly, the occupancy of the state can even increase with its
energy, corresponding to an "anti-proofreading" regime. The number and
properties of such discriminatory regimes are limited by the topology of the
network. Finally, we find that discriminatory regimes can be changed without
modifying any "hard-wired" structural aspects of the system but rather by
simply changing external chemical potentials.


title: Quickest Search over Multiple Sequences with Mixed Observation

abstract:
  The problem of sequentially finding an independent and identically
distributed (i.i.d.) sequence that is drawn from a probability distribution
$f_1$ by searching over multiple sequences, some of which are drawn from $f_1$
and the others of which are drawn from a different distribution $f_0$, is
considered. The observer is allowed to take one observation at a time. It has
been shown in a recent work that if each observation comes from one sequence,
the cumulative sum test is optimal. In this paper, we propose a new approach in
which each observation can be a linear combination of samples from multiple
sequences. The test has two stages. In the first stage, namely scanning stage,
one takes a linear combination of a pair of sequences with the hope of scanning
through sequences that are unlikely to be generated from $f_1$ and quickly
identifying a pair of sequences such that at least one of them is highly likely
to be generated by $f_1$. In the second stage, namely refinement stage, one
examines the pair identified from the first stage more closely and picks one
sequence to be the final sequence. The problem under this setup belongs to a
class of multiple stopping time problems. In particular, it is an ordered two
concatenated Markov stopping time problem. We obtain the optimal solution using
the tools from the multiple stopping time theory. The optimal solution has a
rather complex structure. For implementation purpose, a low complexity
algorithm is proposed, in which the observer adopts the cumulative sum test in
the scanning stage and adopts the sequential probability ratio test in the
refinement stage. The performance of this low complexity algorithm is analyzed
when the prior probability of $f_{1}$ occurring is small. Both analytical and
numerical simulation results show that this search strategy can significantly
reduce the searching time when $f_{1}$ is rare.


title:
Creation of Dirac neutrinos in a dense medium with time-dependent
  effective potential

abstract:
  We consider Dirac neutrinos interacting with background fermions in the frame
of the standard model. We demonstrate that a time-dependent effective potential
is quite possible in a protoneutron star (PNS) at certain stages of its
evolution. For the first time, we formulate a nonperturbative treatment of
neutrino processes in a matter with arbitrary time-dependent effective
potential. Using linearly growing effective potential, we study the typical
case of a slowly varying matter interaction potential. We calculate
differential mean numbers of $\nu \bar{\nu}$ pairs created from the vacuum by
this potential and find that they crucially depend on the magnitude of masses
of the lightest neutrino eigenstate. These distributions uniformly span up to
$\sim 10$ eV energies for muon and tau neutrinos created in PNS core due to the
compression just before the hydrodynamic bounce and up to $\sim 0.1$ eV
energies for all three active neutrino flavors created in the neutronization.
Considering different stages of the PNS evolution, we derive constraints on
neutrino masses, $m_{\nu}\lesssim (10^{-8}-10^{-7})$ eV corresponding to the
nonvanishing $\nu \bar{\nu}$ pairs flux produced by this mechanism. We show
that one can distinguish such coherent flux from chaotic fluxes of any other
origin. Part of these neutrinos, depending on the flavor and helicity, are
bounded in the PNS, while antineutrinos of any flavor escape the PNS. If the
created pairs are $\nu_{e}\bar{\nu}_{e}$, then a part of the corresponding
neutrinos also escape the PNS. The detection of $\nu $ and $\bar{\nu}$ with
such low energies is beyond current experimental techniques.


title: Scale-free networks as an epiphenomenon of memory

abstract:
  Many realistic networks are scale-free, with small characteristic path
lengths, high clustering, and power law in their degree distribution. They can
be obtained by dynamical networks in which a preferential attachment process
takes place. However, this mechanism is non-local, in the sense that it
requires knowledge of the whole graph in order for the graph to be updated.
Instead, if preferential attachment and realistic networks occur in physical
systems, these features need to emerge from a local model. In this paper, we
propose a local model and show that a possible ingredient (which is often
underrated) for obtaining scale-free networks with local rules is memory. Such
a model can be realised in solid-state circuits, using non-linear passive
elements with memory such as memristors, and thus can be tested experimentally.


title: Skyrmions, half-skyrmions and nucleon mass in dense baryonic matter

abstract:
  We explore the hadron properties in dense baryonic matter in a unified way by
using a Skyrme model constructed with an effective Lagrangian which includes
the $\rho$ and $\omega$ vector mesons as hidden gauge bosons and is valid up to
$O(p^4)$ in chiral expansion including the homogeneous Wess-Zumino terms. With
the two input values of pion decay constant and the lowest lying vector meson
mass which can be fixed in free space, all the other low energy constants in
the effective Lagrangian are determined by their master formulas derived from
holographic QCD models, which allows us to study the baryonic matter properties
with no additional free parameters and thus without ambiguities. We find that
the $\omega$ field that figures in the homogeneous Wess-Zumino term plays a
crucial role in the skyrmion structure and its matter properties. The most
striking and intriguing observation is that the pion decay constant that
smoothly drops with increasing density in the Skyrmion phase stops decreasing
at $n_{1/2}^{}$ at which the skyrmions in medium fractionize into
half-skyrmions and remains nearly constant in the half-skyrmion phase. In
accordance with the large $N_c$ consideration, the baryon mass also stays
non-scaling in the half-skyrmion phase. This feature is supported by the
nuclear effective field theory with the parameters of the Lagrangian scaling
modified at the skyrmion--half-skyrmion phase transition. Our exploration also
uncovers the crucial role of the $\omega$ meson in multi-baryon systems as well
as in the structure of a single skyrmion.


title: Predictive analysis of microarray data

abstract:
  Microarray gene expression data are analyzed by means of a Bayesian
nonparametric model, with emphasis on prediction of future observables,
yielding a method for selection of differentially expressed genes and a
classifier.


title: The Pairing of Spin-orbit Coupled Fermi Gas in Optical Lattice

abstract:
  We investigate Rashba spin-orbit coupled Fermi gases in square optical
lattice by using the determinant quantum Monte Carlo (DQMC) simulations which
is free of the sign-problem. We show that the Berezinskii-Kosterlitz-Thoules
phase transition temperature is firstly enhanced and then suppressed by
spin-orbit coupling in the strong attraction region. In the intermediate
attraction region, spin-orbit coupling always suppresses the transition
temperature. We also show that the spin susceptibility becomes anisotropic and
retains finite values at zero temperature.


title: Bounded combinatorics and uniform models for hyperbolic 3-manifolds

abstract:
  Bounded-type 3-manifolds arise as combinatorially bounded gluings of
irreducible 3-manifolds chosen from a finite list. We prove effective
hyperbolization and effective rigidity for a broad class of 3-manifolds of
bounded type and large gluing heights. Specifically, we show the existence and
uniqueness of hyperbolic metrics on 3-manifolds of bounded type and large
heights, and prove existence of a bilipschitz diffeomorphism to a combinatorial
model described explicitly in terms of the list of irreducible manifolds, the
topology of the identification, and the combinatorics of the gluing maps.


title:
Scattering theory for nonlinear Schroedinger equations with
  inverse-square potential

abstract:
  We study the long-time behavior of solutions to nonlinear Schroedinger
equations with some critical rough potential of inverse square type. The new
ingredients are the interaction Morawetz-type inequalities and Sobolev norm
property associated with the Lapalacian with inverse square potential. We use
such properties to obtain the scattering theory for the defocusing
energy-subcritical nonlinear Schroedinger equation with inverse square
potential in energy space.


title:
Interface Tension and Interface Entropy in 2+1 Flavour Nambu-Jona-Lasino
  Model

abstract:
  We study the QCD phases and their transitions in 2+1 flavour NJL model, with
focus on the interface effects such as the interface tension, the interface
entropy and critical bubble size in the coexistence region of the first order
phase transitions. Our results show that, under the thin-wall approximation,
interface contribution to total entropy density changes its discontinuity scale
in the first order phase transition. However, the entropy density of dynamical
chiral symmetry (DCS) phase is always greater than that of the dynamical chiral
symmetry broken (DCSB) phase in both heating and hadronization processes. To
address this entropy puzzle, the thin-wall approximation is evaluated in the
present work. We find that the puzzle can be attributed to a drastic
overestimate of the critical bubble size at low temperature in the
hadronization process. With an improvement on the thin-wall approximation, the
entropy puzzle is well solved with the total entropy density of the hadron-DCSB
phase exceeding apparently that of the DCS-quark phase at low temperature.


title:
Study of Different Solar Cycle Variations of Solar Energetic Particles
  and Cosmic Rays by Despiking ACE/SIS Heavy-Ion Fluxes

abstract:
  Cosmic Rays (CRs) include Galactic Cosmic Rays (GCRs) and Anomalous Cosmic
Rays (ACRs). The CR flux data of protons and heavy-ions observed with
spacecraft are often seriously contaminated by Solar Energetic Particle (SEP)
events. In this work, we separate SEPs from CRs of ACE/SIS spacecraft
observations with an automatic despiking algorithm, so we are able to study the
different variations of SEPs and CRs over a solar cycle. In particular, we
study the elemental ratio, first ionization potential dependence and elemental
dependence, and information entropy of SEPs and CRs. So that we can gain new
insights into energetic particles' different compositions, origins, and
transport processes, etc.


title:
The stability, electronic structure, and optical property of TiO2
  polymorphs

abstract:
  Phonon density of states calculation shows that a new TiO2 polymorph with
tridymite structure is mechanically stable. Enthalpies of 9 TiO2 polymorphs
under different pressure are presented to study the relative stability of the
TiO2 polymorphs. Band structures for the TiO2 polymorphs are calculated by
density functional theory with generalized gradient approximation and the band
energies at high symmetry k-points are corrected using the GW method to
accurately determine the band gap. The differences between direct band gap
energies and indirect band gap energies are very small for rutile, columbite
and baddeleyite TiO2, indicating a quasi-direct band gap character. The band
gap energies of baddeleyite (quasi-direct) and brookite (direct) TiO2 are close
to that of anatase (indirect) TiO2. The band gap of the newly predicted
tridymite-structured TiO2 is wider than the other 8 polymorphs. For optical
response calculations, two-particle effects have been included by solving the
Bethe-Salpeter equation for Coulomb correlated electron-hole pairs. TiO2 with
cotunnite, pyrite, and fluorite structures have optical transitions in the
visible light region.


title: On the Estimation of Pointwise Dimension

abstract:
  Our goal in this paper is to develop an effective estimator of fractal
dimension. We survey existing ideas in dimension estimation, with a focus on
the currently popular method of Grassberger and Procaccia for the estimation of
correlation dimension. There are two major difficulties in estimation based on
this method. The first is the insensitivity of correlation dimension itself to
differences in dimensionality over data, which we term "dimension blindness".
The second comes from the reliance of the method on the inference of limiting
behavior from finite data.
  We propose pointwise dimension as an object for estimation in response to the
dimension blindness of correlation dimension. Pointwise dimension is a local
quantity, and the distribution of pointwise dimensions over the data contains
the information to which correlation dimension is blind. We use a "limit-free"
description of pointwise dimension to develop a new estimator. We conclude by
discussing potential applications of our estimator as well as some challenges
it raises.

categories: physics.data-an math.DS nlin.CD physics.comp-ph stat.ML


title: Social Status and Badge Design

abstract:
  Many websites rely on user-generated content to provide value to consumers.
These websites typically incentivize participation by awarding users badges
based on their contributions. While these badges typically have no explicit
value, they act as symbols of social status within a community. In this paper,
we consider the design of badge mechanisms for the objective of maximizing the
total contributions made to a website. Users exert costly effort to make
contributions and, in return, are awarded with badges. A badge is only valued
to the extent that it signals social status and thus badge valuations are
determined endogenously by the number of users who earn each badge. The goal of
this paper is to study the design of optimal and approximately badge mechanisms
under these status valuations. We characterize badge mechanisms by whether they
use a coarse partitioning scheme, i.e. awarding the same badge to many users,
or use a fine partitioning scheme, i.e. awarding a unique badge to most users.
We find that the optimal mechanism uses both fine partitioning and coarse
partitioning. When status valuations exhibit a decreasing marginal value
property, we prove that coarse partitioning is a necessary feature of any
approximately optimal mechanism. Conversely, when status valuations exhibit an
increasing marginal value property, we prove that fine partitioning is
necessary for approximate optimality.


title: S-duality for surfaces with $A_n$-type singularities

abstract:
  We show that the generating series of Euler characteristics of Hilbert
schemes of points on any algebraic surface with at worst $A_n$-type
singularities is described by the theta series determined by integer valued
positive definite quadratic forms and the Dedekind eta function. In particular
it is a Fourier development of a meromorphic modular form with possibly half
integer weight. The key ingredient is to apply the flop transformation formula
of Donaldson-Thomas type invariants counting two dimensional torsion sheaves on
3-folds proved in the author's previous paper.


title:
Deep 20-GHz survey of the Chandra Deep Field South and SDSS Stripe 82:
  source catalogue and spectral properties

abstract:
  We present a source catalogue and first results from a deep, blind radio
survey carried out at 20 GHz with the Australia Telescope Compact Array, with
follow-up observations at 5.5, 9 and 18 GHz. The Australia Telescope 20 GHz
(AT20G) deep pilot survey covers a total area of 5 deg^2 in the Chandra Deep
Field South and in Stripe 82 of the Sloan Digital Sky Survey. We estimate the
survey to be 90% complete above 2.5 mJy. Of the 85 sources detected, 55% have
steep spectra (alpha_{1.4}^{20} < -0.5) and 45% have flat or inverted spectra
(alpha_{1.4}^{20} >= -0.5).
  The steep-spectrum sources tend to have single power-law spectra between 1.4
and 18 GHz, while the spectral indices of the flat- or inverted-spectrum
sources tend to steepen with frequency. Among the 18 inverted-spectrum
(alpha_{1.4}^{20} >= 0.0) sources, 10 have clearly defined peaks in their
spectra with alpha_{1.4}^{5.5} > 0.15 and alpha_{9}^{18} < -0.15. On a 3-yr
timescale, at least 10 sources varied by more than 15% at 20 GHz, showing that
variability is still common at the low flux densities probed by the AT20G-deep
pilot survey.
  We find a strong and puzzling shift in the typical spectral index of the
15-20 GHz source population when combining data from the AT20G, Ninth Cambridge
and Tenth Cambridge surveys: there is a shift towards a steeper-spectrum
population when going from ~1 Jy to ~5 mJy, which is followed by a shift back
towards a flatter-spectrum population below ~5 mJy. The 5-GHz source-count
model by Jackson & Wall (1999), which only includes contributions from FRI and
FRII sources, and star-forming galaxies, does not reproduce the observed
flattening of the flat-spectrum counts below ~5 mJy. It is therefore possible
that another population of sources is contributing to this effect.


title: The Self-Financing Equation in High Frequency Markets

abstract:
  High Frequency Trading (HFT) represents an ever growing proportion of all
financial transactions as most markets have now switched to electronic order
book systems. The main goal of the paper is to propose continuous time
equations which generalize the self-financing relationships of frictionless
markets to electronic markets with limit order books. We use NASDAQ ITCH data
to identify significant empirical features such as price impact and recovery,
rough paths of inventories and vanishing bid-ask spreads. Starting from these
features, we identify microscopic identities holding on the trade clock, and
through a diffusion limit argument, derive continuous time equations which
provide a macroscopic description of properties of the order book. These
equations naturally differentiate between trading via limit and market orders.
We give several applications (including hedging European options with limit
orders, market maker optimal spread choice, and toxicity indexes) to illustrate
their impact and how they can be used to the benefit of Low Frequency Traders
(LFTs).


title:
Extracting the hadronization timescale in sqrt{s}=7 TeV proton-proton
  collisions from pion and kaon femtoscopy

abstract:
  A hadronic rescattering model with the proper hadronization time width as the
free parameter is compared with charged pion and charged and neutral kaon
femtoscopy measurements from the LHC ALICE experiment for sqrt{s}=7 TeV
proton-proton collisions. Comparisons between the model and measurements are
made for one-dimensional source parameters in several charged multiplicity and
transverse particle pair momentum bins. It is found that a reasonable
description of the measured source parameters by the model is obtained for a
hadronization proper time width of 0.4 +- 0.1 fm/c, which is in agreement with
an estimate based on the uncertainty principle. The model calculations also
suggest that 1) some form of collectivity is necessary to describe the
multiplicity dependence of the measured radius parameters, and 2) the
underlying physical size and timescale of the collision is significantly larger
than what the extracted radius parameters and hadronization proper time width
would imply.


title: Isomorphisms of $AC(\sigma)$ spaces

abstract:
  Analogues of the classical Banach-Stone theorem for spaces of continuous
functions are studied in the context of the spaces of absolutely continuous
functions introduced by Ashton and Doust. We show that if $AC(\sigma_1)$ is
algebra isomorphic to $AC(\sigma_2)$ then $\sigma_1$ is homeomorphic to
$\sigma_2$. The converse however is false. In a positive direction we show that
the converse implication does hold if the sets $\sigma_1$ and $\sigma_2$ are
confined to a restricted collection of compact sets, such as the set of all
simple polygons.


title:
Limit sets of Teichm\"uller geodesics with minimal non-uniquely ergodic
  vertical foliation

abstract:
  We describe a method for constructing Teichm\"uller geodesics where the
vertical measured foliation $\nu$ is minimal but is not uniquely ergodic and
where we have a good understanding of the behavior of the Teichm\"uller
geodesic. The construction depends on various parameters, and we show that one
can adjust the parameters to ensure that the set of accumulation points of such
a geodesic in the Thurston boundary is exactly the set of all possible measured
foliations in the homotopy class of $\nu$. With further adjustment of the
parameters, one can even take $\nu$ to be an ergodic measure on a non-uniquely
ergodic foliation.


title:
Dominant block guided optimal cache size estimation to maximize IPC of
  embedded software

abstract:
  Embedded system software is highly constrained from performance, memory
footprint, energy consumption and implementing cost view point. It is always
desirable to obtain better Instructions per Cycle. Instruction cache has major
contribution in improving IPC. Cache memories are realized on the same chip
where the processor is running. This considerably increases the system cost as
well. Hence, it is required to maintain a trade off between cache sizes and
performance improvement offered. Determining the number of cache lines and size
of cache line are important parameters for cache designing. The design space
for cache is quite large. It is time taking to execute the given application
with different cache sizes on an instruction set simulator to figure out the
optimal cache size. In this paper, a technique is proposed to identify a number
of cache lines and cache line size for the L1 instruction cache that will offer
best or nearly best IPC. Cache size is derived, at a higher abstraction level,
from basic block analysis in the Low Level Virtual Machine environment. The
cache size estimated is cross validated by simulating the set of benchmark
applications with different cache sizes in simple scalar simulator. The
proposed method seems to be superior in terms of estimation accuracy and
estimation time as compared to the existing methods for estimation of optimal
cache size parameters like cache line size, number of cache lines.


title:
Stochastic Lagrangian flows on the group of volume-preserving
  homeomorphisms of the spheres

abstract:
  We consider stochastic differential equations on the group of
volume-preserving homeomorphisms of the sphere $S^d\,(d\geq 2)$. The diffusion
part is given by the divergence free eigenvector fields of the Laplacian acting
on $L^2$-vector fields, while the drift is some other divergence free vector
field. We show that the equation generates a unique flow of measure-preserving
homeomorphisms when the drift has first order Sobolev regularity, and derive a
formula for the distance between two Lagrangian flows. We also compute the
rotation process of two particles on the sphere $S^2$ when they are close to
each other.


title: Note about lepton masses and mixings in two Ansatze

abstract:
  We consider two Ansatze for the neutrino masses and mixings in which the
permutation symmetry is implemented in various orders. We discuss the possible
see-saw mechanisms and the charged lepton masses for the two cases in the
presence of a Higgs triplet and three Higgs doublets.


title: A Weak Galerkin Finite Element Method for the Maxwell Equations

abstract:
  This paper introduces a numerical scheme for time harmonic Maxwell's
equations by using weak Galerkin (WG) finite element methods. The WG finite
element method is based on two operators: discrete weak curl and discrete weak
gradient, with appropriately defined stabilizations that enforce a weak
continuity of the approximating functions. This WG method is highly flexible by
allowing the use of discontinuous approximating functions on arbitrary shape of
polyhedra and, at the same time, is parameter free. Optimal-order of
convergence is established for the weak Galerkin approximations in various
discrete norms which are either $H^1$-like or $L^2$ and $L^2$-like. An
effective implementation of the WG method is developed through variable
reduction by following a Schur-complement approach, yielding a system of linear
equations involving unknowns associated with element boundaries only. Numerical
results are presented to confirm the theory of convergence.


title:
Characterization of large area photomultiplier ETL 9357FLB for liquid
  argon detector

abstract:
  The China Dark Matter Experiment (CDEX) Collaboration will carry out a direct
search for weakly interacting massive particles with germanium detectors.
Liquid argon will be utilized as an anti-Compton and cooling material for the
germanium detectors. A low-background and large-area photomultiplier tube (PMT)
immersed in liquid argon will be used to read out the light signal from the
argon. In this paper we carry out a careful evaluation on the performance of
the PMT operating at both room and cryogenic temperatures. Based on the single
photoelectron response model, the absolute gain and resolution of the PMT were
measured. This has laid a foundation for PMT selection, calibration and signal
analysis in the forthcoming CDEX experiments.


title:
Simple groups of automorphisms of trees determined by their actions on
  finite subtrees

abstract:
  We introduce the notion of the $k$-closure of a group of automorphisms of a
locally finite tree, and give several examples of the construction. We show
that the $k$-closure satisfies a new property of automorphism groups of trees
that generalises Tits' Property $P$. We prove that, apart from some degenerate
cases, any non-discrete group acting on a tree with this property contains an
abstractly simple subgroup.


title:
Universal Extra-Dimensional models with boundary terms: Probing at the
  LHC

abstract:
  In universal extra-dimensional models a conserved Z_2 parity stabilizes the
lightest Kaluza-Klein particle, a dark-matter candidate. Boundary-localized
kinetic terms, in general, do not preserve this symmetry. We examine, in the
presence of such terms, the single production of Kaluza-Klein excitations of
the neutral electroweak gauge bosons and their decay to zero-mode
fermion-antifermion pairs. We explore how experiments at the Large Hadron
Collider constrain the boundary-localized kinetic terms for different
compactification radii.


title:
Precision Astronomy with Imperfect Fully Depleted CCDs -- An
  Introduction and a Suggested Lexicon

abstract:
  This paper summarizes the introductory presentation for a workshop that
explored the challenges of making precision astronomical measurements using
deeply depleted (thick) CCDs. While thick CCDs provide definite advantages in
terms of increased quantum efficiency at NIR wavelengths, and reduced fringing
from atmospheric emission lines, these devices also exhibit undesirable
features that pose a challenge to precision determination of the positions,
fluxes, and shapes of astronomical objects, and features in astronomical
spectra. Many of the effects seen in these devices arise from lateral
electrical fields within the detector, that produce charge transport anomalies
that have been previously misinterpreted as quantum efficiency variations.
Performing simplistic flat-fielding introduces systematic errors in the image
processing pipeline. One measurement challenge is devising a calibration method
that can distinguish genuine quantum efficiency variations from charge
transport effects. Given the scientific benefits of improving both the
precision and accuracy of astronomical measurements, we need to identify,
characterize, and overcome these various detector artifacts. In retrospect,
many of the detector features first identified in thick CCDs also afflict
measurements made with more traditional CCD detectors, albeit often at a
reduced level. I provide a qualitative overview of the physical effects we
think are responsible for the observed device properties, and provide some
perspective for the work that lies ahead. Finally, I take this opportunity to
make a plea for establishing a clear and consistent vocabulary when describing
these various detector features, and make some suggestions for a standard
lexicon based on discussions at the workshop.


title: Exploring the Roper wave function in Lattice QCD

abstract:
  Using a correlation matrix analysis consisting of a variety of smearings, the
CSSM Lattice collaboration has successfully isolated states associated with the
Roper resonance and other "exotic" excited states such as the $\Lambda(1405)$
on the lattice at near-physical pion masses. We explore the nature of the Roper
by examining the eigenvectors that arise from the variational analysis,
demonstrating that the Roper state is dominated by the $\chi_1$ nucleon
interpolator and only poorly couples to $\chi_2.$ By examining the probability
distribution of the Roper on the lattice, we find a structure consistent with a
constituent quark model. In particular, the Roper $d$-quark wave function
contains a single node consistent with a $2S$ state. A detailed comparison with
constituent quark model wave functions is carried out, validating the approach
of accessing these states by constructing a variational basis composed of
different levels of fermion source and sink smearing.


title: Noisy Bayesian Active Learning

abstract:
  We consider the problem of noisy Bayesian active learning, where we are given
a finite set of functions $\mathcal{H}$, a sample space $\mathcal{X}$, and a
label set $\mathcal{L}$. One of the functions in $\mathcal{H}$ assigns labels
to samples in $\mathcal{X}$. The goal is to identify the function that
generates the labels even though the result of a label query on a sample is
corrupted by independent noise. More precisely, the objective is to declare one
of the functions in $\mathcal{H}$ as the true label generating function with
high confidence using as few label queries as possible, by selecting the
queries adaptively and in a strategic manner.
  Previous work in Bayesian active learning considers Generalized Binary
Search, and its variants for the noisy case, and analyzes the number of queries
required by these sampling strategies. In this paper, we show that these
schemes are, in general, suboptimal. Instead we propose and analyze an
alternative strategy for sample collection. Our sampling strategy is motivated
by a connection between Bayesian active learning and active hypothesis testing,
and is based on querying the label of a sample which maximizes the Extrinsic
Jensen-Shannon divergence at each step. We provide upper and lower bounds on
the performance of this sampling strategy, and show that these bounds are
better than previous bounds.


title:
Comparing the Overhead of Topological and Concatenated Quantum Error
  Correction

abstract:
  This work compares the overhead of quantum error correction with concatenated
and topological quantum error-correcting codes. To perform a numerical
analysis, we use the Quantum Resource Estimator Toolbox (QuRE) that we recently
developed. We use QuRE to estimate the number of qubits, quantum gates, and
amount of time needed to factor a 1024-bit number on several candidate quantum
technologies that differ in their clock speed and reliability. We make several
interesting observations. First, topological quantum error correction requires
fewer resources when physical gate error rates are high, white concatenated
codes have smaller overhead for physical gate error rates below approximately
10E-7. Consequently, we show that different error-correcting codes should be
chosen for two of the studied physical quantum technologies - ion traps and
superconducting qubits. Second, we observe that the composition of the
elementary gate types occurring in a typical logical circuit, a fault-tolerant
circuit protected by the surface code, and a fault-tolerant circuit protected
by a concatenated code all differ. This also suggests that choosing the most
appropriate error correction technique depends on the ability of the future
technology to perform specific gates efficiently.


title: QED cascade induced by high energy $\gamma$ photon in strong laser field

abstract:
  The QED cascade induced by the two counter-propagating lasers is studied. It
is demonstrated that the probability of a seed-photon to create a pair is much
larger than that of a seed-electron. By analyzing the dynamic characteristics
of the electron and positron created by the seed-photon, it is found that the
created particles are more probable to emit photons than the seed-electron.
With these result, further more, we also demonstrate that the QED cascade can
be easier to be triggered by the seed-photon than by the seed-electron with the
same incident energy and the same laser.


title: Constructing $7$-clusters

abstract:
  A set of $n$-lattice points in the plane, no three on a line and no four on a
circle, such that all pairwise distances and all coordinates are integral is
called an $n$-cluster (in $\mathbb{R}^2$). We determine the smallest existent
$7$-cluster with respect to its diameter. Additionally we provide a toolbox of
algorithms which allowed us to computationally locate over 1000 different
$7$-clusters, some of them having huge integer edge lengths. On the way, we
exhaustively determined all Heronian triangles with largest edge length up to
$6\cdot 10^6$.


title:
A Risk-driven Model for Work Allocation in Global Software Development
  Projects

abstract:
  Risks and potential benefits of distributing software development projects
globally depend to a large extent on how to allocate work to different
development sites and regions. Existing methods in task allocation are likely
to omit the relevance of considering a multitude of criteria and the impact of
task distribution on risks and potential benefits. To assess risks stemming
from specific work distributions and to exploit organization-specific
experience, we have developed a customizable risk-driven model. It consists of
two main steps: Suggesting a set of task allocation alternatives based on
project- and site-specific characteristics and analyzing it with respect to
possible project risks stemming from the work distribution. To evaluate the
model, we conducted a series of semi-structured interviews in a multinational
IT company. The results of the evaluation show that the suggestions of the
model mostly comply with the retrospective views voiced by the involved
experienced managers.


title: Quantum confinement in Si and Ge nanostructures: Effect of crystallinity

abstract:
  We look at the relationship between the preparation method of Si and Ge
nanostructures (NSs) and the structural, electronic, and optical properties in
terms of quantum confinement (QC). QC in NSs causes a blue shift of the gap
energy with decreasing NS dimension. Directly measuring the effect of QC is
complicated by additional parameters, such as stress, interface and defect
states. In addition, differences in NS preparation lead to differences in the
relevant parameter set. A relatively simple model of QC, using a
`particle-in-a-box'-type perturbation to the effective mass theory, was applied
to Si and Ge quantum wells, wires and dots across a variety of preparation
methods. The choice of the model was made in order to distinguish contributions
that are solely due to the effects of QC, where the only varied experimental
parameter was the crystallinity. It was found that the hole becomes
de-localized in the case of amorphous materials, which leads to stronger
confinement effects. The origin of this result was partly attributed to
differences in the effective mass between the amorphous and crystalline NS as
well as between the electron and hole. Corrections to our QC model take into
account a position dependent effective mass. This term includes an inverse
length scale dependent on the displacement from the origin. Thus, when the
deBroglie wavelength or the Bohr radius of the carriers is on the order of the
dimension of the NS the carriers `feel' the confinement potential altering
their effective mass. Furthermore, it was found that certain interface states
(Si-O-Si) act to pin the hole state, thus reducing the oscillator strength.


title:
Role of Quantum Confinement in Luminescence Efficiency of Group IV
  Nanostructures

abstract:
  Experimental results obtained previously for the photoluminescence efficiency
(PL$_{eff}$) of Ge quantum dots (QDs) are theoretically studied. A
$\log$-$\log$ plot of PL$_{eff}$ versus QD diameter ($D$) resulted in an
identical slope for each Ge QD sample only when $E_{G}\sim (D^2+D)^{-1}$. We
identified that above $D\approx$ 6.2 nm: $E_{G}\sim D^{-1}$ due to a changing
effective mass (EM), while below $D\approx$ 4.6 nm: $E_{G}\sim D^{-2}$ due to
electron/ hole confinement. We propose that as the QD size is initially
reduced, the EM is reduced, which increases the Bohr radius and interface
scattering until eventually pure quantum confinement effects dominate at small
$D$.


title:
Memory function approach to in-plane anisotropic resistivity in the
  antiferromagnetic phase of iron arsenide superconductors

abstract:
  We theoretically examine anisotropy of in-plane resistivity in the striped
antiferromagnetic phase of an iron arsenide superconductor by applying a memory
function approach to the ordered phase with isotropic nonmagnetic impurity. We
find that the anisotropy of the scattering rate is independent of carrier
density when the topology of the Fermi surface is changed after the
introduction of holes. On the other hand, the anisotropy of the Drude weight
monotonically decreases reflecting the distortion of the Dirac Fermi surface
and eventually leads to the reverse of anisotropy of resistivity, being
consistent with experiment. The origin of the anisotropy is thus attributed to
the interplay of impurity scattering and anisotropic electronic states.


title: Architectural Pattern of Health Care System Using GSM Networks

abstract:
  Large-scale networked environments, such as the Internet, possess the
characteristics of centralised data, centralised access and centralised
control; this gives the user a powerful mechanism for building and integrating
large repositories of centralised information from diverse resources set.
However, a centralised network system with GSM Networks development for a
hospital information systems or a health care information portal is still in
its infancy. The shortcomings of the currently available tools have made the
use of mobile devices more appealing. In mobile computing, the issues such as
low bandwidth, high latency wireless Networks, loss or degradation of wireless
connections, and network errors or failures need to be dealt with. Other issues
to be addressed include system adaptability, reliability, robustness,
extensibility, flexibility, and maintainability. GSM approach has emerged as
the most viable approach for development of intelligent software applications
for wireless mobile devices in a centralized environment, which gives higher
band width of 900 MHz for transmission. The e-healthcare system that we have
developed provides support for physicians, nurses, pharmacists and other
healthcare professionals, as well as for patients and medical devices used to
monitor patients. In this paper, we present the architecture and the
demonstration prototype.


title: Asymptotic expansions for SDE's with small multiplicative noise

abstract:
  Asymptotic expansions are derived as power series in a small coefficient
entering a nonlinear multiplicative noise and a deterministic driving term in a
nonlinear evolution equation. Detailed estimates on remainders are provided.


title: Pattern Based Adaptive Architecture for Internet Banking

abstract:
  Pattern plays a vital role in software architecture and it is a general
reusable solution to commonly occurring problem. Software architecture of a
system is the set of structures needed to reason about the system, which
comprise software elements, relations among them, and properties of both.
Patterns can be implemented at run-time; they identify key resource constraints
and best practices. Architecture Pattern expresses a fundamental structural
organization or schema for software systems. Patterns in software architecture,
offer the promise of helping the architect to identify combinations of
Architecture or Solution Building Blocks that have been proven to deliver
effective solutions. In Internet banking, we analyzed some attributes such as
reliability, security, availability, load balancing and so on. The use of
patterns, which is of a reusable component, is a good tool to help designers
build load balancing systems. In this paper we are going to propose pattern
based adaptive architecture for internet banking system and so the above
attributes can be improved by the usage of patterns.


title:
Gravitational radiation from an axion cloud around a black hole:
  Superradiant phase

abstract:
  Motivated by possible existence of string axions with ultralight masses, we
study gravitational radiation from an axion cloud around a rotating black hole
(BH). The axion cloud extracts the rotation energy of the BH by superradiant
instability, while it loses energy through the emission of gravitational waves
(GWs). In this paper, GWs are treated as perturbations on a fixed background
spacetime to derive the energy emission rate. We give an analytic approximate
formula for the case where axion's Compton wavelength is much larger than the
BH radius, and then, present numerical results without approximation. The
energy loss rate of the axion cloud through the GW emission turns out to be
smaller than the energy gain rate of the axion cloud by superradiant
instability until nonlinear self-interactions of axions become important. In
particular, an axion bosenova must happen at the last stage of superradiant
instability.


title: Strategy pattern: payment pattern for Internet banking

abstract:
  This paper brings out the design patterns according to the various services
involved in internet banking. The Pattern oriented Software Architecture uses
the pattern which eliminates the difficulty of reusability in a particular
context. The patterns are to be designed using BPM (Business Process Model) for
effective cross cutting on process level. For implementing the above said BPM,
the Internet banking has been taken to implement the pattern into it. The
Analysis and identification of various processes in Internet Banking have been
done, to identify the effective cross cutting features. With this process the
pattern has been designed, as a reusability component to be used by the
Software Architect. The pattern help us to resolve recurring problems
constructively and based on proven solutions and also support us in
understanding the architecture of a given software system. Once the model is
finalized by analyzing, we found payment in the process of internet banking has
a strategy pattern.


title:
The least dense hyperball covering to the regular prism tilings in the
  hyperbolic $n$-space

abstract:
  After having investigated the densest packings by congruent hyperballs to the
regular prism tilings in the $n$-dimensional hyperbolic space $\mathbb{H}^n$
($n \in \mathbb{N}, n \ge 3)$ we consider the dual covering problems and
determine the least dense hyperball arrangements and their densities.


title:
Stability and electronic properties of two-dimensional silicene and
  germanene on graphene

abstract:
  We present first-principles calculations of silicene/graphene and
germanene/graphene bilayers. Various supercell models are constructed in the
calculations in order to reduce the strain of the lattice-mismatched bilayer
systems. Our energetics analysis and electronic structure results suggest that
graphene can be used as a substrate to synthesize monolayer silicene and
germanene. Multiple phases of single crystalline silicene and germanene with
different orientations relative to the substrate could coexist at room
temperature. The weak interaction between the overlayer and the substrate
preserves the low-buckled structure of silicene and germanene, as well as their
linear energy bands. The gap induced by breaking the sublattice symmetry in
silicene on graphene can be up to 57 meV.


title:
A Provocative Summary: Is There Any Unified Model for Triggering Active
  Galactic Nuclei ?

abstract:
  A provocative summary of the conference on "Galaxy Mergers in an Evolving
Universe" is presented. The conference includes the following issues; 1)
Mergers at low redshift, 2) Merger dynamics and numerical simulations, 3)
Mergers in galaxy evolution, 4) Mergers and active galactic nuclei (AGNs), 5)
Mergers at high redshift and submm galaxies, 6) Feedback from starbursts and
AGNs, 6) Chemical evolution of galaxies, and 7) Results from new surveys.
Although there are many important issues related to galaxy mergers and nuclear
activities in galaxies, in this summary, l et us focus on following the
question; {\it Is there any unified model for triggering nuclear activities ?}
Given key observational properties of galaxies with AGNs, a possible unified
model is discussed as an evolutionary model from starbursts to AGNs based on
minor and major mergers between/among galaxies.


title: Radiation field simulation of C-ADS Injector II

abstract:
  The injector of C-ADS (Chinese Accelerator Driven Sub-critical System)
project is a high current, fully super-conducting proton accelerator.
Meanwhile, a BLM system is indispensable to this facility, especially in low
energy segments. This paper presents some basic simulations for 10MeV proton by
Monte Carlo program FLUKA, as well as the distributions on different secondary
particles in three aspects: angular, energy spectrum and current. These results
are beneficial to selecting the detector type and its location and determining
its dynamic range matching different requirements for both fast and slow beam
loss. Further, the major impact of the background is analyzed, such as
superconducting cavity X radiation and radiation caused by material activation,
in this paper as well. This work is meaningful in BLM system research.


title: Cultural Astronomy and Archaeoastronomy: an Italian Experience

abstract:
  A brief review is given of some recent positive developments regarding the
reception of archaeoastronomy by the archaeological institutions in Italy.
Discussions and problems that are currently going on in this field are also
mentioned, such as the separation of the scientific and humanistic disciplines
(i.e. the two cultures problem). Suggestions based on contemporary philosophy
are also reported. Finally, sky-gazing is proposed as the place where the two
cultures could meet, since, taking Plato into account, sky-gazing could be
considered the mom of the human knowledge, and of the scientific and humanistic
disciplines.


title: Exploiting Data Representation for Fault Tolerance

abstract:
  We explore the link between data representation and soft errors in dot
products. We present an analytic model for the absolute error introduced should
a soft error corrupt a bit in an IEEE-754 floating-point number. We show how
this finding relates to the fundamental linear algebra concepts of
normalization and matrix equilibration. We present a case study illustrating
that the probability of experiencing a large error in a dot product is
minimized when both vectors are normalized. Furthermore, when data is
normalized we show that the absolute error is less than one or very large,
which allows us to detect large errors. We demonstrate how this finding can be
used by instrumenting the GMRES iterative solver. We count all possible errors
that can be introduced through faults in arithmetic in the computationally
intensive orthogonalization phase, and show that when scaling is used the
absolute error can be bounded above by one.


title: Inferring Algebraic Effects

abstract:
  We present a complete polymorphic effect inference algorithm for an ML-style
language with handlers of not only exceptions, but of any other algebraic
effect such as input & output, mutable references and many others. Our main aim
is to offer the programmer a useful insight into the effectful behaviour of
programs. Handlers help here by cutting down possible effects and the resulting
lengthy output that often plagues precise effect systems. Additionally, we
present a set of methods that further simplify the displayed types, some even
by deliberately hiding inferred information from the programmer.


title: Charmless Two-body Baryonic $B_{u,d,s}$ Decays Revisited

abstract:
  We study charmless two-body baryonic $B$ decays using the topological
amplitude approach. We extend a previous work to include all ground state octet
and decuplet final states with full topological amplitudes. Relations on rates
and CP asymmetries are obtained. The number of independent topological
amplitudes is significantly reduced in the large $m_B$ asymptotic limit. With
the long awaited $\overline B{}^0\to p\bar p$ data, we can finally extract
information on the topological amplitudes and predict rates of all other modes.
The predicted rates are in general with uncertainties of a factor of two by
including corrections to the asymptotic relations and from sub-leading
contributions. We point out some modes that will cascadely decay to all charged
final states and have large decay rates. For example, $\overline B
{}^0_s\to\Omega^-\overline{\Omega^-}$, $B^-\to p\overline{\Delta^{++}}$,
$B^-\to \Lambda\bar p$ and $\overline B{}^0_s\to \Lambda\overline{\Lambda}$
decays are interesting modes to search for. We find that the $\overline
B{}^0\to p\bar p$ mode is the most accessible one among octet-anti-octet final
states in the $\Delta S=0$ transition. It is not surprise that it is the first
one being found. With the detection of $\pi^0$ and/or $\gamma$ many other
unsuppressed modes can be searched for. The predicted $\overline B{}^0_s\to
p\bar p$ rate is several order smaller than the present experimental result.
The central value of the experimental result can be reproduced only with
unnaturally scaled up "subleading contributions", which will affect other modes
including the $\overline B{}^0\to p\bar p$ decay. We need more data to clarify
the situation. The analysis presented in this work can be systematically
improved when more measurements on decay rates become available.


title: Hierarchical scale-free network is fragile against random failure

abstract:
  We investigate site percolation in a hierarchical scale-free network known as
the Dorogovtsev- Goltsev-Mendes network. We use the generating function method
to show that the percolation threshold is 1, i.e., the system is not in the
percolating phase when the occupation probability is less than 1. The present
result is contrasted to bond percolation in the same network of which the
percolation threshold is zero. We also show that the percolation threshold of
intentional attacks is 1. Our results suggest that this hierarchical scale-free
network is very fragile against both random failure and intentional attacks.
Such a structural defect is common in many hierarchical network models.


title: Are two given maps homotopic? An algorithmic viewpoint

abstract:
  This paper presents two algorithms. In their simplest form, the first
algorithm decides the existence of a pointed homotopy between given simplicial
maps f, g from X to Y and the second computes the group $[\Sigma X,Y]^*$ of
pointed homotopy classes of maps from a suspension; in both cases, the target Y
is assumed simply connected and the algorithms run in polynomial time when the
dimension of X is fixed. More generally, these algorithms work relative to a
subspace A of X, fibrewise over a simply connected B and also equivariantly
when all spaces are equipped with a free action of a fixed finite group G.


title:
Practical Design for Multiple-Antenna Cognitive Radio Networks with
  Coexistence Constraint

abstract:
  In this paper we investigate the practical design for the multiple-antenna
cognitive radio (CR) networks sharing the geographically used or unused
spectrum. We consider a single cell network formed by the primary users (PU),
which are half-duplex two-hop relay channels and the secondary users (SU) are
single user additive white Gaussian noise channels. In addition, the
coexistence constraint which requires PUs' coding schemes and rates unchanged
with the emergence of SU, should be satisfied. The contribution of this paper
are twofold. First, we explicitly design the scheme to pair the SUs to the
existing PUs in a single cell network. Second, we jointly design the nonlinear
precoder, relay beamformer, and the transmitter and receiver beamformers to
minimize the sum mean square error of the SU system. In the first part, we
derive an approximate relation between the relay ratio, chordal distance and
strengths of the vector channels, and the transmit powers. Based on this
relation, we are able to solve the optimal pairing between SUs and PUs
efficiently. In the second part, considering the feasibility of implementation,
we exploit the Tomlinson-Harashima precoding instead of the dirty paper coding
to mitigate the interference at the SU receiver, which is known side
information at the SU transmitter. To complete the design, we first approximate
the optimization problem as a convex one. Then we propose an iterative
algorithm to solve it with CVX. This joint design exploits all the degrees of
design. To the best of our knowledge, both the two parts have never been
considered in the literature. Numerical results show that the proposed pairing
scheme outperforms the greedy and random pairing with low complexity. Numerical
results also show that even if all the channel matrices are full rank, under
which the simple zero forcing scheme is infeasible, the proposed scheme can
still work well.


title: Long-Range triplet Josephson Current driven by the bias voltage

abstract:
  We study the long-range triplet Josephson current in a clean junction
composed of two s-wave superconductors and a
normal-metal/ferromagnet/normal-metal trilayer. Through applying the bias
voltages on the metal regions by two antiparallel half-metal electrodes, we
show that the amplitude and direction of this long-range current can be
controlled easily and flexibly. Such current arises from the fact that the
applied voltage can produce a nonequilibrium spin-dependent quasiparticle
distribution in the metal regions so that the Cooper pairs acquire an extra
momenta, which will lead to a spin-flip processes in the metal regions. This
processes can produce the parallel spin triplet pairs in the central
ferromagnet layer. In particular, if the voltage is applied only on one metal
region, we further find that the recently discovered long-range superharmonic
Josephson current will appear because of the transport of an even number of
parallel spin triplet pairs.


title:
Scaling limit of a limit order book model via the regenerative
  characterization of L\'evy trees

abstract:
  We consider the following Markovian dynamic on point processes: at constant
rate and with equal probability, either the rightmost atom of the current
configuration is removed, or a new atom is added at a random distance from the
rightmost atom. Interpreting atoms as limit buy orders, this process was
introduced by Lakner et al. to model a one-sided limit order book. We consider
this model in the regime where the total number of orders converges to a
reflected Brownian motion, and complement the results of Lakner et al. by
showing that, in the case where the mean displacement at which a new order is
added is positive, the measure-valued process describing the whole limit order
book converges to a simple functional of this reflected Brownian motion. Our
results make it possible to derive useful and explicit approximations on
various quantities of interest such as the depth or the total value of the
book. Our approach leverages an unexpected connection with L\'evy trees. More
precisely, the cornerstone of our approach is the regenerative characterization
of L\'evy trees due to Weill, which provides an elegant proof strategy which we
unfold.


title: Visitor Pattern: Implementation of Enquiry Pattern for Internet Banking

abstract:
  This paper brings out the design patterns according to the various services
involved in internet banking. The Pattern oriented Software Architecture uses
the pattern which eliminates the difficulty of reusability in a particular
context. The patterns are to be designed using BPM (Business Process Model) for
effective cross cutting on process level. For implementing the above said BPM,
the Internet banking has been taken to implement the pattern into it. The
Analysis and identification of various processes in Internet Banking have been
done, to identify the effective cross cutting features. With this process the
pattern has been designed, as a reusability component to be used by the
Software Architect. The pattern help us to resolve recurring problems
constructively and based on proven solutions and also support us in
understanding the architecture of a given software system. Once the model is
finalized by analyzing we found enquiry pattern as the visitor pattern and
implement the pattern.


title:
Evaluation of Software Architecture Quality Attribute for an Internet
  Banking System

abstract:
  The design phase plays a vital role than all other phases in the software
development. Software Architecture has to meet both the functional and
non-functional quality requirements. The Evaluation of Architecture has to be
performed, so that the developers are assured that their selected Architecture
will reduce the cost and effort and also enhances the various quality
attributes like Availability, Reusability, Performance, Modifiability and
Extendibility. The success of the system depends upon the Architecture
Evaluation by the essential method to the system. The overall ranking of the
candidate architecture is ascertained by assigning weight to the scenario and
scenario interaction. In this paper, SAAM method is taken to evaluate the two
architectures from the various available method and techniques to achieve the
various quality attributes by weight metric.


title: Property of LCP-GEM in Pure Dimethyl Ether at Low Pressure

abstract:
  We present a systematic investigation of the gain properties of a gas
electron multiplier (GEM) foil in pure dimethyl ether (DME) at low pressures.
The GEM is made from copper- clad liquid crystal polymer insulator (LCP-GEM)
designed for space use, and is applied to a time projection chamber filled with
low-pressure DME gas to observe the linear polarization of cosmic X-rays. We
have measured gains of a 100 um-thick LCP-GEM as a function of the voltage
between GEM electrodes at various gas pressures ranging from 10 to 190 Torr
with 6.4 keV X-rays. The highest gain at 190 Torr is about 2x10^4, while that
at 20 Torr is about 500. We find that the pressure and electric-field
dependence of the GEM gain is described by the first Townsend coefficient. The
energy scale from 4.5 to 8.0 keV is linear with non-linearity of less than 1.4%
above 30 Torr.


title: Request and notification Pattern for an internet banking System

abstract:
  The quality of software is enhanced by using the design patterns. The design
patterns are the reusable component used in the development of the software,
which delivers improved quality software to the end users. The researchers have
developed design patterns for user interface, e-commerce applications, mobile
applications, text classification and so on. There are no design patterns for
internet banking applications, but there is analysis pattern for banking. This
motivated to mine the design patterns for internet banking application. It can
be mined from the document of Business Process Management (BPM). In this paper
the request and notification are two patterns, that have been presented, which
have been mined from internet banking.


title: Metastable domain wall dynamics in magnetic nanowires

abstract:
  We study the formation and control of metastable states of pairs of domain
walls in cylindrical nanowires of small diameter where the transverse walls are
the lower energy state. We show that these pairs form bound states under
certain conditions, with a lifetime as long as 200ns, and are stabilized by the
influence of a spin polarized current. Their stability is analyzed with a model
based on the magnetostatic interaction and by 3D micromagnetic simulations. The
apparition of bound states could hinder the operation of devices.


title:
Testing the $a_\mu$ anomaly in the electron sector through a precise
  measurement of $h/M$

abstract:
  The persistent $a_\mu \equiv (g-2)/2$ anomaly in the muon sector could be due
to new physics visible in the electron sector through a sub-ppb measurement of
the anomalous magnetic moment of the electron $a_e$. Driven by recent results
on the electron mass (S. Sturm et al., Nature 506 (2014) 467), we reconsider
the sources of uncertainties that limit our knowledge of $a_e$ including
current advances in atom interferometry. We demonstrate that it is possible to
attain the level of precision needed to test $a_\mu$ in the naive scaling
hypothesis on a timescale similar to next generation $g-2$ muon experiments at
Fermilab and JPARC. In order to achieve such level of precision, the knowledge
of the quotient $h/M$, i.e. the ratio between the Planck constant and the mass
of the atom employed in the interferometer, will play a crucial role. We
identify the most favorable isotopes to achieve an overall relative precision
below $10^{-10}$.


title: Fast Bayesian inference for slow-roll inflation

abstract:
  We present and discuss a new approach increasing by orders of magnitude the
speed of performing Bayesian inference and parameter estimation within the
framework of slow-roll inflation. The method relies on the determination of an
effective likelihood for inflation which is a function of the primordial
amplitude of the scalar perturbations complemented with the necessary number of
the so-called Hubble flow functions to reach the desired accuracy. Starting
from any cosmological data set, the effective likelihood is obtained by
marginalisation over the standard cosmological parameters, here viewed as
"nuisance" from the early Universe point of view. As being low-dimensional,
basic machine-learning algorithms can be trained to accurately reproduce its
multidimensional shape and then be used as a proxy to perform fast Bayesian
inference on the inflationary models. The robustness and accuracy of the method
are illustrated using the Planck Cosmic Microwave Background (CMB) data to
perform primordial parameter estimation for the large field models of
inflation. In particular, marginalised over all possible reheating history, we
find the power index of the potential to verify p < 2.3 at 95% of confidence.


title:
Interplay between Hund's coupling and spin-orbit interaction on
  elementary excitations in Sr2IrO4

abstract:
  We study the elementary excitations in 5d transition metal oxideSr$_2$IrO$_4$
by calculating the particle-hole Green's function within the random phase
approximation on an antiferromagnetic ground state in the two-dimensional
multi-orbital Hubbard model. The obtained magnetic excitations of bound states
show a characteristic dispersion in consistent with the experiments. In
addition, two new types of excitations are found due to the interplay between
spin-orbit interaction and Hund's coupling: a magnetic excitation as a bound
state, which has energy gap at the $\Gamma$ point, and an exciton as a resonant
mode in the continuum of electron-hole pair creation.


title: Universal Quantum Graphs

abstract:
  For time-reversal invariant graphs we prove the Bohigas-Giannoni-Schmit
conjecture in its most general form: For graphs that are mixing in the
classical limit, all spectral correlation functions coincide with those of the
Gaussian Orthogonal Ensemble of random matrices. For open graphs, we derive the
analogous identities for all S matrix correlation functions.


title:
On one-loop corrections to matching conditions of Lattice HQET including
  1/m_b terms

abstract:
  HQET is an effective theory for QCD with N_f light quarks and a massive
valence quark if the mass of the latter is much bigger than Lambda_QCD. As any
effective theory, HQET is predictive only when a set of parameters has been
determined through a process called matching. The non-perturbative matching
procedure including 1/m_b terms, developped by the ALPHA collaboration,
consists of 19 carefully chosen observables which are precisely computable in
lattice QCD as well as in lattice HQET. The matching conditions are then a set
of 19 equations which relate the QCD and HQET values of these observables. We
present a study of one-loop corrections to two generic matching observables
involving correlation function with an insertion of the A_0 operator. Our
results enable us to quantify the quality of the relevant observables in view
of the envisaged non-perturbative implementation of this matching procedure.


title: Optimal control of Allen-Cahn systems

abstract:
  Optimization problems governed by Allen-Cahn systems including elastic
effects are formulated and first-order necessary optimality conditions are
presented. Smooth as well as obstacle potentials are considered, where the
latter leads to an MPEC. Numerically, for smooth potential the problem is
solved efficiently by the Trust-Region-Newton-Steihaug-cg method. In case of an
obstacle potential first numerical results are presented.


title:
Cross section and reaction rate of 92Mo(p,gamma)93Tc determined from
  thick target yield measurements

abstract:
  For the better understanding of the astrophysical gamma-process the
experimental determination of low energy proton- and alpha-capture cross
sections on heavy isotopes is required. The existing data for the
92Mo(p,gamma)93Tc reaction are contradictory and strong fluctuation of the
cross section is observed which cannot be explained by the statistical model.
In this paper a new determination of the 92Mo(p,gamma)93Tc and
98Mo(p,gamma)99mTc cross sections based on thick target yield measurements are
presented and the results are compared with existing data and model
calculations. Reaction rates of 92Mo(p,gamma)93Tc at temperatures relevant for
the gamma-process are derived directly from the measured thick target yields.
The obtained rates are a factor of 2 lower than the ones used in astrophysical
network calculations. It is argued that in the case of fluctuating cross
sections the thick target yield measurement can be more suited for a reliable
reaction rate determination.


title:
On the difference between checking integrity constraints before or after
  updates

abstract:
  Integrity checking is a crucial issue, as databases change their instance all
the time and therefore need to be checked continuously and rapidly. Decades of
research have produced a plethora of methods for checking integrity constraints
of a database in an incremental manner. However, not much has been said about
when to check integrity. In this paper, we study the differences and
similarities between checking integrity before an update (a.k.a. pre-test) or
after (a.k.a. post-test) in order to assess the respective convenience and
properties.


title: Variational Truncated Wigner Approximation

abstract:
  In this paper we reconsider the notion of an optimal effective Hamiltonian
for the semiclassical propagation of the Wigner distribution in phase space. An
explicit expression for the optimal effective Hamiltonian is obtained in the
short time limit by minimizing the Hilbert-Schmidt distance between the
semiclassical approximation and the real state of the system. The method is
illustrated for the quartic oscillator.


title:
On the dependency on the size of the data when chasing under conceptual
  dependencies

abstract:
  Conceptual dependencies (CDs) are particular kinds of key dependencies (KDs)
and inclusion dependencies (IDs) that precisely characterize relational
schemata modeled according to the main features of the Entity-Relationship (ER)
model. An instance for such a schema may be inconsistent (data violate the
dependencies) and incomplete (data constitute a piece of correct information,
but not necessarily all the relevant information). While undecidable under
general KDs and IDs, query answering under incomplete data is known to be
decidable for CDs. The known techniques are based on the chase -- a special
instance, organized in levels of depth, that is a representative of all the
instances that satisfy the dependencies and that include the initial instance.
Although the chase generally has infinite size, query answering can be
addressed by posing the query (or a rewriting thereof) on a finite, initial
part of the chase. Contrary to previous claims, we show that the maximum level
of such an initial part cannot be bounded by a constant that does not depend on
the size of the initial instance.


title: Multi-material phase field approach to structural topology optimization

abstract:
  Multi-material structural topology and shape optimization problems are
formulated within a phase field approach. First-order conditions are stated and
the relation of the necessary conditions to classical shape derivatives are
discussed. An efficient numerical method based on an $H^1$-gradient projection
method is introduced and finally several numerical results demonstrate the
applicability of the approach.


title: Spectroscopic study of the magnetic ground state of Nb$_{1-y}$Fe$_{2+y}$

abstract:
  We have investigated single crystals and polycrystals from the series
Nb$_{1-y}$Fe$_{2+y}$, $-0.004 \leq y \leq 0.018$ by electron spin resonance,
muon spin relaxation and M\"ossbauer spectroscopy. Our data establish that at
lowest temperatures all samples exhibit bulk magnetic order. Slight Fe-excess
induces low-moment ferromagnetism, consistent with bulk magnetometry ($\simeq
0.06 ~\mu_B/{\rm Fe}$), Nb--rich and stoichiometric NbFe$_2$ display spin
density wave order with small magnetic moment amplitudes of the order $\sim
0.001 - 0.01 ~\mu_B/{\rm Fe}$. This provides microscopic evidence for a
modulated magnetic state on the border of ferromagnetism in NbFe$_2$.


title: Exact Recovery for Sparse Signal via Weighted $l_1$ Minimization

abstract:
  Numerical experiments in literature on compressed sensing have indicated that
the reweighted $l_1$ minimization performs exceptionally well in recovering
sparse signal. In this paper, we develop exact recovery conditions and
algorithm for sparse signal via weighted $l_1$ minimization from the insight of
the classical NSP (null space property) and RIC (restricted isometry constant)
bound. We first introduce the concept of WNSP (weighted null space property)
and reveal that it is a necessary and sufficient condition for exact recovery.
We then prove that the RIC bound by weighted $l_1$ minimization is
$\delta_{ak}<\sqrt{\frac{a-1}{a-1+\gamma^2}}$, where $a>1$, $0<\gamma\leq1$ is
determined by an optimization problem over the null space. When $\gamma< 1$
this bound is greater than $\sqrt{\frac{a-1}{a}}$ from $l_1$ minimization. In
addition, we also establish the bound on $\delta_k$ and show that it can be
larger than the sharp one 1/3 via $l_1$ minimization and also greater than
0.4343 via weighted $l_1$ minimization under some mild cases. Finally, we
achieve a modified iterative reweighted $l_1$ minimization (MIRL1) algorithm
based on our selection principle of weight, and the numerical experiments
demonstrate that our algorithm behaves much better than $l_1$ minimization and
iterative reweighted $l_1$ minimization (IRL1) algorithm.


title:
Towards Ontological Support for Principle Solutions in Mechanical
  Engineering

abstract:
  The engineering design process follows a series of standardized stages of
development, which have many aspects in common with software engineering. Among
these stages, the principle solution can be regarded as an analogue of the
design specification, fixing as it does the way the final product works. It is
usually constructed as an abstract sketch (hand-drawn or constructed with a CAD
system) where the functional parts of the product are identified, and geometric
and topological constraints are formulated. Here, we outline a semantic
approach where the principle solution is annotated with ontological assertions,
thus making the intended requirements explicit and available for further
machine processing; this includes the automated detection of design errors in
the final CAD model, making additional use of a background ontology of
engineering knowledge. We embed this approach into a document-oriented design
workflow, in which the background ontology and semantic annotations in the
documents are exploited to trace parts and requirements through the design
process and across different applications.


title: Structure of $^{13}$Be probed via secondary beam reactions

abstract:
  The low-lying level structure of the unbound neutron-rich nucleus $^{13}$Be
has been investigated via breakup on a carbon target of secondary beams of
$^{14,15}$B at 35 MeV/nucleon. The coincident detection of the beam velocity
$^{12}$Be fragments and neutrons permitted the invariant mass of the
$^{12}$Be+$n$ and $^{12}$Be+$n$+$n$ systems to be reconstructed. In the case of
the breakup of $^{15}$B, a very narrow structure at threshold was observed in
the $^{12}$Be+$n$ channel. Contrary to earlier stable beam fragmentation
studies which identified this as a strongly interacting $s$-wave virtual state
in $^{13}$Be, analysis here of the $^{12}$Be+$n$+$n$ events demonstrated that
this was an artifact resulting from the sequential-decay of the
$^{14}$Be(2$^+$) state. Single-proton removal from $^{14}$B was found to
populate a broad low-lying structure some 0.70 MeV above the neutron-decay
threshold in addition to a less prominent feature at around 2.4 MeV. Based on
the selectivity of the reaction and a comparison with (0-3)$\hbar\omega$
shell-model calculations, the low-lying structure is concluded to most probably
arise from closely spaced J$^\pi$=1/2$^+$ and 5/2$^+$ resonances
(E$_r$=0.40$\pm$0.03 and 0.85$^{+0.15}_{-0.11}$ MeV), whilst the broad
higher-lying feature is a second 5/2$^+$ level (E$_r$=2.35$\pm$0.14 MeV). Taken
in conjunction with earlier studies, it would appear that the lowest 1/2$^+$
and 1/2$^-$ levels lie relatively close together below 1 MeV.


title: Connecting Mirror Symmetry in 3d and 2d via Localization

abstract:
  We explicitly apply localization results to study the interpolation between
three and two dimensional mirror symmetry for Abelian gauge theories with four
supercharges. We first use the ellipsoid S_b^3 partition functions to verify
the mirror symmetry between a pair of general three dimensional N=2 Abelian
Chern-Simons quiver gauge theories. These expressions readily factorize into
holomorphic blocks and their anti-holomorphic copies, so we can also obtain the
partition functions on S^1 x S^2 via fusion procedure. We then demonstrate S^1
x S^2 partition functions for the three dimensional Abelian gauge theories can
be dimensionally reduced to the S^2 partition functions of N=(2,2) GLSM and
Landau-Ginzburg model for the corresponding two dimensional mirror pair, as
anticipated previously in \cite{Aganagic:2001uw}. We also comment on the
analogous interpolation for the non-Abelian gauge theories and compute the
K-theory vortex partition function for a simple limit to verify the prediction
from holomorphic block.


title:
Modelling the income distribution in the European Union: An application
  for the initial analysis of the recent worldwide financial crisis

abstract:
  By using methods of statistical physics, we focus on the quantitative
analysis of the economic income data descending from different databases. To
explain our approach, we introduce the necessary theoretical background, the
extended Yakovenko et al. (EY) model. This model gives an analytical
description of the annual household incomes of all society classes in the
European Union (i.e., the low-, medium-, and high-income ones) by a single
unified formula based on unified formalism. We show that the EY model is very
useful for the analyses of various income datasets, in particular, in the case
of a smooth matching of two different datasets. The completed database which we
have constructed using this matching emphasises the significance of the
high-income society class in the analysis of all household incomes. For
instance, the Pareto exponent, which characterises this class, defines the Zipf
law having an exponent much lower than the one characterising the medium-income
society class. This result makes it possible to clearly distinguish between
medium- and high-income society classes. By using our approach, we found that
the high-income society class almost disappeared in 2009, which defines this
year as the most difficult for the EU. To our surprise, this is a contrast with
2008, considered the first year of a worldwide financial crisis, when the
status of the high-income society class was similar to that of 2010. This,
perhaps, emphasises that the crisis in the EU was postponed by about one year
in comparison with the United States.


title:
A reference-invariant health disparity index based on R\'{e}nyi
  divergence

abstract:
  One of four overarching goals of Healthy People 2020 (HP2020) is to achieve
health equity, eliminate disparities, and improve the health of all groups. In
health disparity indices (HDIs) such as the mean log deviation (MLD) and Theil
index (TI), disparities are relative to the population average, whereas in the
index of disparity (IDisp) the reference is the group with the least adverse
health outcome. Although the latter may be preferable, identification of a
reference group can be affected by statistical reliability. To address this
issue, we propose a new HDI, the R\'{e}nyi index (RI), which is
reference-invariant. When standardized, the RI extends the Atkinson index,
where a disparity aversion parameter can incorporate societal values associated
with health equity. In addition, both the MLD and TI are limiting cases of the
RI. Also, a symmetrized R\'{e}nyi index (SRI) can be constructed, resulting in
a symmetric measure in the two distributions whose relative entropy is being
evaluated. We discuss alternative symmetric and reference-invariant HDIs
derived from the generalized entropy (GE) class and the Bregman divergence, and
argue that the SRI is more robust than its GE-based counterpart to small
changes in the distribution of the adverse health outcome. We evaluate the
design-based standard errors and bootstrapped sampling distributions for the
SRI, and illustrate the proposed methodology using data from the National
Health and Nutrition Examination Survey (NHANES) on the 2001-04 prevalence of
moderate or severe periodontitis among adults aged 45-74, which track Oral
Health objective OH-5 in HP2020. Such data, which use a binary individual-level
outcome variable, are typical of HP2020 data.


title: Letter to the Editor

abstract:
  The paper by Alfons, Croux and Gelper (2013), Sparse least trimmed squares
regression for analyzing high-dimensional large data sets, considered a
combination of least trimmed squares (LTS) and lasso penalty for robust and
sparse high-dimensional regression. In a recent paper [She and Owen (2011)], a
method for outlier detection based on a sparsity penalty on the mean shift
parameter was proposed (designated by "SO" in the following). This work is
mentioned in Alfons et al. as being an "entirely different approach." Certainly
the problem studied by Alfons et al. is novel and interesting.


title: Dynamics-generating semigroups and phenomenology of decoherence

abstract:
  The earlier proposed Dynamics-Generating Approach (DGA) is reviewed and
extended. Starting from an arbitrarily chosen group or semigroup which have
structure similar to the structure of Galilei group, DGA allows one to
construct phenomenological description of dynamics of the corresponding
"elementary quantum object" (a particle or non-local object of special type). A
class of Galilei-type semigroups, with semigroup of trajectories (parametrized
paths) instead of translations, allows one to derive Feynman path integrals in
the framework of DGA. The measure of path integrating (exponential of the
classic action) is not postulated but derived from the structure of projective
semigroup representations. The generalization of DGA suggested in the present
paper allows one to derive dynamics of open quantum systems. Specifically,
phenomenological description of decoherence and dissipation of a
non-relativistic particle is derived from Galilei semigroup.


title:
A preliminary survey on optimized multiobjective metaheuristic methods
  for data clustering using evolutionary approaches

abstract:
  The present survey provides the state-of-the-art of research, copiously
devoted to Evolutionary Approach (EAs) for clustering exemplified with a
diversity of evolutionary computations. The Survey provides a nomenclature that
highlights some aspects that are very important in the context of evolutionary
data clustering. The paper missions the clustering trade-offs branched out with
wide-ranging Multi Objective Evolutionary Approaches (MOEAs) methods. Finally,
this study addresses the potential challenges of MOEA design and data
clustering, along with conclusions and recommendations for novice and
researchers by positioning most promising paths of future research. MOEAs have
substantial success across a variety of MOP applications, from pedagogical
multifunction optimization to real-world engineering design. The survey paper
noticeably organizes the developments witnessed in the past three decades for
EAs based metaheuristics to solve multiobjective optimization problems (MOP)
and to derive significant progression in ruling high quality elucidations in a
single run. Data clustering is an exigent task, whose intricacy is caused by a
lack of unique and precise definition of a cluster. The discrete optimization
problem uses the cluster space to derive a solution for Multiobjective data
clustering. Discovery of a majority or all of the clusters (of illogical
shapes) present in the data is a long-standing goal of unsupervised predictive
learning problems or exploratory pattern analysis.


title: High Dimensional Expanders and Property Testing

abstract:
  We show that the high dimensional expansion property as defined by Gromov,
Linial and Meshulam, for simplicial complexes is a form of testability. Namely,
a simplicial complex is a high dimensional expander iff a suitable property is
testable. Using this connection, we derive several testability results.


title:
A Unified Markov Chain Approach to Analysing Randomised Search
  Heuristics

abstract:
  The convergence, convergence rate and expected hitting time play fundamental
roles in the analysis of randomised search heuristics. This paper presents a
unified Markov chain approach to studying them. Using the approach, the
sufficient and necessary conditions of convergence in distribution are
established. Then the average convergence rate is introduced to randomised
search heuristics and its lower and upper bounds are derived. Finally, novel
average drift analysis and backward drift analysis are proposed for bounding
the expected hitting time. A computational study is also conducted to
investigate the convergence, convergence rate and expected hitting time. The
theoretical study belongs to a prior and general study while the computational
study belongs to a posterior and case study.


title: Flexible estimation in cure survival models using Bayesian P-splines

abstract:
  In the analysis of survival data, it is usually assumed that any unit will
experience the event of interest if it is observed for a sufficient long time.
However, one can explicitly assume that an unknown proportion of the population
under study will never experience the monitored event. The promotion time
model, which has a biological motivation, is one of the survival models taking
this feature into account. The promotion time model assumes that the failure
time of each subject is generated by the minimum of N latent event times which
are independent with a common distribution independent of N. We propose an
extension which allows the covariates to influence simultaneously the
probability of being cured and the latent distribution. We estimate the latent
distribution using a flexible Cox proportional hazard model where the logarithm
of the baseline hazard function is specified using Bayesian P-splines.
Introducing covariates in the latent distribution implies that the population
hazard function might not have a proportional hazard structure. However, the
use of the P-splines provides a smooth estimation of the population hazard
ratio over time. We propose a restricted use of the model when the follow up of
the study is not sufficiently long. A simulation study evaluating the accuracy
of our methodology is presented. The proposed model is illustrated on data from
the phase III Melanoma e1684 clinical trial.


title:
A family of nonlinear difference equations: existence, uniqueness, and
  asymptotic behavior of positive solutions

abstract:
  We study solutions $(x_n)_{n \in \mathbb{N}}$ of nonhomogeneous nonlinear
second order difference equations of the type $\ell_n = x_n ( \sigma_{n,1}
x_{n+1} + \sigma_{n,0} x_n + \sigma_{n,-1} x_{n-1} ) + \kappa_n x_n$, with
given initial data $x_0 \in \mathbb{R}$, $x_1 \in \mathbb{R}^+$ where
$(\ell_n)_{n\in\mathbb{N}} \in \mathbb{R}^+$, $(\sigma_{n,0})_{n\in\mathbb{N}}
\in \mathbb{R}^+$ and $(\kappa_n)_{n\in\mathbb{N}} \in \mathbb{R}$ and the left
and right $\sigma$-coefficients satisfy either $(\sigma_{n,1})_{n\in\mathbb{N}}
\in \mathbb{R}^+$ and $(\sigma_{n,-1})_{n\in \mathbb{N}} \in \mathbb{R}^+$ or
$(\sigma_{n,1})_{n\in\mathbb{N}} \in \mathbb{R}^+_0$ and
$(\sigma_{n,-1})_{n\in\mathbb{N}} \in \mathbb{R}^+_0$. Depending on one's
standpoint, such equations originate either from orthogonal polynomials
associated with certain Shohat-Freud-type exponential weight functions or from
Painlev\'e's discrete equation $\#1$.


title:
Tight Bounds for the Price of Anarchy of Simultaneous First Price
  Auctions

abstract:
  We study the Price of Anarchy of simultaneous first-price auctions for buyers
with submodular and subadditive valuations. The current best upper bounds for
the Bayesian Price of Anarchy of these auctions are e/(e-1) [Syrgkanis and
Tardos 2013] and 2 [Feldman et al. 2013], respectively. We provide matching
lower bounds for both cases even for the case of full information and for mixed
Nash equilibria via an explicit construction.
  We present an alternative proof of the upper bound of e/(e-1) for first-price
auctions with fractionally subadditive valuations which reveals the worst-case
price distribution, that is used as a building block for the matching lower
bound construction.
  We generalize our results to a general class of item bidding auctions that we
call bid-dependent auctions (including first-price auctions and all-pay
auctions) where the winner is always the highest bidder and each bidder's
payment depends only on his own bid.
  Finally, we apply our techniques to discriminatory price multi-unit auctions.
We complement the results of [de Keijzer et al. 2013] for the case of
subadditive valuations, by providing a matching lower bound of 2. For the case
of submodular valuations, we provide a lower bound of 1.109. For the same class
of valuations, we were able to reproduce the upper bound of e/(e-1) using our
non-smooth approach.


title: Labeled Random Finite Sets and the Bayes Multi-Target Tracking Filter

abstract:
  We present an efficient numerical implementation of the $\delta$-Generalized
Labeled Multi-Bernoulli multi-target tracking filter. Each iteration of this
filter involves an update operation and a prediction operation, both of which
result in weighted sums of multi-target exponentials with intractably large
number of terms. To truncate these sums, the ranked assignment and K-th
shortest path algorithms are used in the update and prediction, respectively,
to determine the most significant terms without exhaustively computing all of
the terms. In addition, using tools derived from the same framework, such as
probability hypothesis density filtering, we present inexpensive look-ahead
strategies to reduce the number of computations. Characterization of the
$L_{1}$-error in the multi-target density arising from the truncation is
presented.


title: Magnetic Fields in Stars: Origin and Impact

abstract:
  Various types of magnetic fields occur in stars: small scale fields, large
scale fields, and internal toroidal fields. While the latter may be ubiquitous
in stars due to differential rotation, small scale fields (spots) may be
associated with envelop convection in all low and high mass stars. The stable
large scale fields found in only about 10 per cent of intermediate mass and
massive stars may be understood as a consequence of dynamical binary
interaction, e.g., the merging of two stars in a binary. We relate these ideas
to magnetic fields in white dwarfs and neutron stars, and to their role in
core-collapse and thermonuclear supernova explosions.