title:
On exact statistics and classification of ergodic systems of integer
  dimension

abstract:
  We describe classes of ergodic dynamical systems for which some statistical
properties are known exactly. These systems have integer dimension, are not
globally dissipative, and are defined by a probability density and a two-form.
This definition generalizes the construction of Hamiltonian systems by a
Hamiltonian and a symplectic form. Some low dimensional examples are given, as
well as a discretized field theory with a large number of degrees of freedom
and a local nearest neighbor interaction. We also evaluate unequal-time
correlations of these systems without direct numerical simulation, by Pad\'e
approximants of a short-time expansion. We briefly speculate on the possibility
of constructing chaotic dynamical systems with non-integer dimension and
exactly known statistics. In this case there is no probability density,
suggesting an alternative construction in terms of a Hopf characteristic
function and a two-form.


title: Non-integer optical modes in a M\"obius-ring resonator

abstract:
  In-plane polarized light experiences a non-trivial topological evolution as
it propagates resonantly in a M\"obius ring resonator. The resultant geometric
phase varies continuously when changing the light ellipticity, which leads to
constructive interference for a non-integer number of wavelengths, and
therefore to the occurrence of an arbitrary fractional number of optical modes.
The geometric phase in M\"obius-ring resonators is topologically robust and
implies excellent intrinsic fault-tolerance.


title: Simple Harmonic Motion:Geometrical Solutions of Equations of Motions

abstract:
  Conventionally while we talk about geometry associated with a simple harmonic
oscillator, we draw a circle with a radius equal to the amplitude of Oscillator
and imagine a particle moving along the perimeter with a frequency same as that
of Oscillator and then the x coordinate of the position of the particle gives
the value of the displacement of the Oscillator. Here we discuss another kind
of diagram (polar plot) depicting dynamics of Oscillator and come up with a
solution to boundary and initial value problem geometrically.


title:
Numerical validation of the electromagnetic gyrokinetic code NEMORB on
  global axisymmetric modes

abstract:
  This is a report about a comparison of collisionless simulations on global
modes (i.e. low poloidal mode number) with gyrokinetic code NEMORB against
analytical theory and other codes. Only axisymmetric modes, i.e. with toroidal
mode number n=0, are considered, and flat equilibrium profiles. Benchmarks are
performed for GAMs against local analytical theory. In the presence of
energetic ions, local benchmarks of NEMORB are performed against semilagrangian
gyrokinetic code GYSELA. The models of adiabatic vs trapped-kinetic- vs
fully-kinetic-electrons and of electrostatic vs electromagnetic at very low
beta are compared. Scalings of Alfven modes are also presented.


title:
Comparing two matrices of generalized moments defined by continued
  fraction expansions

abstract:
  We study two matrices $N$ and $M$ defined by the parameters of equivalent
$S$- and $J$-continued fraction expansions, and compare them by examining the
product $N^{-1}M$. Using examples based on the Catalan numbers, the little
Schr\"oder numbers and powers of $q$, we indicate that this matrix product is
an object worthy of study. In the case of the little Schr\"oder numbers, we
find that the matrix $N$ has an interleaved structure based on two Riordan
arrays.


title: A short note on p-adic families of Hilbert Modular Forms

abstract:
  We extend previous work of the author using an idea of Buzzard and give an
elementary construction of non-ordinary $p$-adic families of Hilbert Modular
Eigenforms.


title: Nonlocal and nonlinear electrostatics of a dipolar Coulomb fluid

abstract:
  We study a model Coulomb fluid consisting of dipolar solvent molecules of
finite extent generalizing the point-like Dipolar Poisson-Boltzmann model (DPB)
previously introduced by Coalson and Duncan (J. Phys. Chem 100, 2612 (1996))
and Abrashkin et al. (Phys. Rev. Lett. 99, 077801 (2007)). We formulate a
nonlocal Poisson-Boltzmann equation (NLPB) and study both linear and nonlinear
dielectric response in this model for the case of a single plane geometry. Our
results shed light on the relevance of nonlocal vs nonlinear effects in
continuum models of material electrostatics.


title:
Deuteron electromagnetic form factors in a renormalizable formulation of
  chiral effective field theory

abstract:
  We calculate the deuteron electromagnetic form factors in a modified version
of Weinberg's chiral effective field theory approach to the two-nucleon system.
We derive renormalizable integral equations for the deuteron without partial
wave decomposition. Deuteron form factors are extracted by applying the
Lehmann-Symanzik-Zimmermann reduction formalism to the three-point correlation
function of deuteron interpolating fields and the electromagnetic current
operator. Numerical results of a leading-order calculation with removed cutoff
regularization agree well with experimental data.


title:
Sharp embedding of Sobolev spaces involving general kernels and its
  application

abstract:
  The purpose of this paper is to extend the embedding theorem of Sobolev
spaces involving general kernels and we provide a sharp critical exponent in
these embeddings. As an application, solutions for equations driven by a
general integro-differential operator, with homogeneous Dirichlet boundary
conditions, is established by using the Mountain Pass Theorem.


title:
On critical behaviour in systems of Hamiltonian partial differential
  equations

abstract:
  We study the critical behaviour of solutions to weakly dispersive Hamiltonian
systems considered as perturbations of elliptic and hyperbolic systems of
hydrodynamic type with two components. We argue that near the critical point of
gradient catastrophe of the dispersionless system, the solutions to a suitable
initial value problem for the perturbed equations are approximately described
by particular solutions to the Painlev\'e-I (P$_I$) equation or its fourth
order analogue P$_I^2$. As concrete examples we discuss nonlinear Schr\"odinger
equations in the semiclassical limit. A numerical study of these cases provides
strong evidence in support of the conjecture.


title: Spectra of lens spaces from 1-norm spectra of congruence lattices

abstract:
  To every $n$-dimensional lens space $L$, we associate a congruence lattice
$\mathcal L$ in $\mathbb Z^m$, with $n=2m-1$ and we prove a formula relating
the multiplicities of Hodge-Laplace eigenvalues on $L$ with the number of
lattice elements of a given $\|\cdot\|_1$-length in $\mathcal L$. As a
consequence, we show that two lens spaces are isospectral on functions (resp.\
isospectral on $p$-forms for every $p$) if and only if the associated
congruence lattices are $\|\cdot\|_1$-isospectral (resp.\
$\|\cdot\|_1$-isospectral plus a geometric condition). Using this fact, we
give, for every dimension $n\ge 5$, infinitely many examples of Riemannian
manifolds that are isospectral on every level $p$ and are not strongly
isospectral.


title: Continuity of the asymptotics of expected zeros of fewnomials

abstract:
  In "Random complex fewnomials, I," B. Shiffman and S. Zelditch determine the
limiting formula as N goes to infinity of the (normalized) expected
distribution of complex zeros of a system of k random n-nomials in m variables
where the coefficients are taken from the SU(m+1) ensemble and the spectra are
chosen uniformly at random. We recall their result and show the limiting
formula is a (k,k)-form with continuous coefficients.


title: A new procedure for defining a homogenous line-list for solar-type stars

abstract:
  Context. The homogenization of the stellar parameters is an important goal
for large observational spectroscopic surveys, but it is very difficult to
achieve it because of the diversity of the spectroscopic analysis methods used
within a survey, such as spectrum synthesis and the equivalent width method. To
solve this problem, constraints to the spectroscopic analysis can be set, such
as the use of a common line-list. Aims. We present a procedure for selecting
the best spectral lines from a given input line-list, which then allows us to
derive accurate stellar parameters with the equivalent width method. Methods.
To select the lines, we used four very well known benchmark stars, for which we
have high-quality spectra. From an initial line-list, the equivalent width of
each individual line was automatically measured for each benchmark star using
ARES, then we performed a local thermodynamic equilibrium analysis with MOOG to
compute individual abundances. The results allowed us to choose the best lines
which give consistent abundance values for all the benchmark stars from which
we then created a final line-list. Results. To verify its consistency, the
compiled final line-list was tested for a small sample of stars. These stars
were selected to cover different ranges in the parameter space for FGK stars.
We show that the obtained parameters agree well with previously determined
values.


title: Exact Convex Relaxation of Optimal Power Flow in Radial Networks

abstract:
  The optimal power flow (OPF) problem determines power generation/demand that
minimize a certain objective such as generation cost or power loss. It is
nonconvex. We prove that, for radial networks, after shrinking its feasible set
slightly, the global optimum of OPF can be recovered via a second-order cone
programming (SOCP) relaxation under a condition that can be checked a priori.
The condition holds for the IEEE 13-, 34-, 37-, 123-bus networks and two
real-world networks, and has a physical interpretation.


title:
Minimal Number of Steps in Euclidean Algorithm and its Application to
  Rational Tangles

abstract:
  We define the regular Euclidean algorithm and the general form which leads to
the method of least absolute remainders and also the method of negative
remainders. We are going to show that if looked from the perspective of
subtraction, the method of least absolute remainders and the regular method
have the same number of steps which is in fact the minimal number of steps
possible. This enables us to apply the theory in rational tangles to determine
the most efficient way to untangle a rational tangle.


title: The critical CoHA of a quiver with potential

abstract:
  Pursuing the similarity between the Kontsevich--Soibelman construction of the
cohomological Hall algebra of BPS states and Lusztig's construction of
canonical bases for quantum enveloping algebras, and the similarity between the
inetgrality conjecture for motivic Donaldson--Thomas invariants and the PBW
theorem for quantum enveloping algebras, we build a coproduct on the
cohomological Hall algebra associated to a quiver with potential. We also prove
a cohomological dimensional reduction theorem, further linking a special class
of cohomological Hall algebras with Yangians, and explaining how to connect the
study of character varieties with the study of cohomological Hall algebras.


title: Unparticle Casimir effect

abstract:
  In this paper we present the un-Casimir effect, namely the study of the
Casimir energy in the presence of an unparticle component in addition to the
electromagnetic field contribution. The distinctive feature of the un-Casimir
effect is a fractalization of metallic plates. This result emerges through a
new dependence of the Casimir energy on the plate separation that scales with a
continuous power controlled by the unparticle dimension. As long as the perfect
conductor approximation is valid, we find bounds on the unparticle scale that
are independent of the effective coupling constant between the scale invariant
sector and ordinary matter. We find regions of the parameter space such that
for plate distances around $5\mu$m and larger the un-Casimir bound wins over
the other bounds.


title:
Optimizing gravitational-wave searches for a population of coalescing
  binaries: Intrinsic parameters

abstract:
  We revisit the problem of searching for gravitational waves from inspiralling
compact binaries in Gaussian coloured noise. For binaries with quasicircular
orbits and non-precessing component spins, considering dominant mode emission
only, if the intrinsic parameters of the binary are known then the optimal
statistic for a single detector is the well-known two-phase matched filter.
However, the matched filter signal-to-noise ratio is /not/ in general an
optimal statistic for an astrophysical population of signals, since their
distribution over the intrinsic parameters will almost certainly not mirror
that of noise events, which is determined by the (Fisher) information metric.
Instead, the optimal statistic for a given astrophysical distribution will be
the Bayes factor, which we approximate using the output of a standard template
matched filter search. We then quantify the possible improvement in number of
signals detected for various populations of non-spinning binaries: for a
distribution of signals uniformly distributed in volume and with component
masses distributed uniformly over the range $1\leq m_{1,2}/M_\odot\leq 24$,
$(m_1+m_2) /M_\odot\leq 25$ at fixed expected SNR, we find $\gtrsim 20\%$ more
signals at a false alarm threshold of $10^{-6}\,$Hz in a single detector. The
method may easily be generalized to binaries with non-precessing spins.

categories: gr-qc astro-ph.CO astro-ph.HE physics.data-an


title:
The Impulsive Phase in Solar Flares: Recent Multi-wavelength Results and
  their Implications for Microwave Modeling and Observations

abstract:
  This short paper reviews several recent key observations of the processes
occurring in the lower atmosphere (chromosphere and photosphere) during flares.
These are: evidence for compact and fragmentary structure in the flare
chromosphere, the conditions in optical flare footpoints, step-like variations
in the magnetic field during the flare impulsive phase, and hot, dense
'chromospheric' footpoints. The implications of these observations for
microwaves are also discussed.


title: Nonequilibrium heat capacity

abstract:
  Development of steady state thermodynamics and statistical mechanics depends
crucially on our ability to develop notions of equilibrium thermodynamics for
nonequilibrium steady states (NESS). The present paper considers the
development of heat capacity. A modified definition is proposed which continues
to maintain the same relation to steady state Shannon entropy as in
equilibrium, thus providing a thermodynamically consistent treatment of NESS
heat capacity.


title: On the life and scientific work of Gino Fano

abstract:
  A collection of selected papers of Gino Fano, containing most of his research
papers in Italian, is now available on line at the site of Biblioteca Digitale
Italiana di Matematica. The address is: http://www.bdim.eu/ The realization of
this collection on line is part of a joint project of Unione Matematica
Italiana (UMI) and Societa' Italiana per la Matematica Applicata e Industriale
(SIMAI). The present submission to arXiv is the introduction to the collection
and an announcement of it as well.


title:
Efficient deterministic approximate counting for low-degree polynomial
  threshold functions

abstract:
  We give a deterministic algorithm for approximately counting satisfying
assignments of a degree-$d$ polynomial threshold function (PTF). Given a
degree-$d$ input polynomial $p(x_1,\dots,x_n)$ over $R^n$ and a parameter
$\epsilon> 0$, our algorithm approximates $\Pr_{x \sim \{-1,1\}^n}[p(x) \geq
0]$ to within an additive $\pm \epsilon$ in time $O_{d,\epsilon}(1)\cdot
\mathop{poly}(n^d)$. (Any sort of efficient multiplicative approximation is
impossible even for randomized algorithms assuming $NP\not=RP$.) Note that the
running time of our algorithm (as a function of $n^d$, the number of
coefficients of a degree-$d$ PTF) is a \emph{fixed} polynomial. The fastest
previous algorithm for this problem (due to Kane), based on constructions of
unconditional pseudorandom generators for degree-$d$ PTFs, runs in time
$n^{O_{d,c}(1) \cdot \epsilon^{-c}}$ for all $c > 0$.
  The key novel contributions of this work are: A new multivariate central
limit theorem, proved using tools from Malliavin calculus and Stein's Method.
This new CLT shows that any collection of Gaussian polynomials with small
eigenvalues must have a joint distribution which is very close to a
multidimensional Gaussian distribution. A new decomposition of low-degree
multilinear polynomials over Gaussian inputs. Roughly speaking we show that (up
to some small error) any such polynomial can be decomposed into a bounded
number of multilinear polynomials all of which have extremely small
eigenvalues. We use these new ingredients to give a deterministic algorithm for
a Gaussian-space version of the approximate counting problem, and then employ
standard techniques for working with low-degree PTFs (invariance principles and
regularity lemmas) to reduce the original approximate counting problem over the
Boolean hypercube to the Gaussian version.


title: Hecke algebras and symplectic reflection algebras

abstract:
  The current article is a short survey on the theory of Hecke algebras, and in
particular Kazhdan-Lusztig theory, and on the theory of symplectic reflection
algebras, and in particular rational Cherednik algebras. The emphasis is on the
connections between Hecke algebras and rational Cherednik algebras that could
allow us to obtain a generalised Kazhdan-Lusztig theory, or at least its
applications, for all complex reflection groups.


title:
SN 2005ip: A Luminous Type IIn Supernova Emerging from a Dense
  Circumstellar Medium as Revealed by X-Ray Observations

abstract:
  We report on X-ray spectral evolution of the nearby Type IIn supernova (SN)
2005ip, based on Chandra and Swift observations covering from ~1 to 6 years
after the explosion. X-ray spectra in all epochs are well fitted by a thermal
emission model with kT > 7 keV. The somewhat high temperature suggests that the
X-ray emission mainly arises from the circumstellar medium heated by the
forward shock. We find that the spectra taken 2-3 years since the explosion are
heavily absorbed N_H ~ 5e22 cm^{-2}, but the absorption gradually decreases to
the level of the Galactic absorption N_H ~ 4e20 cm^{-2} at the final epoch.
This indicates that the SN went off in a dense circumstellar medium and that
the forward shock has overtaken it. The intrinsic X-ray luminosity stays
constant until the final epoch when it drops by a factor of ~2. The intrinsic
0.2-10 keV luminosity during the plateau phase is measured to be ~1.5e41 erg/s,
ranking SN 2005ip as one of the brightest X-ray SNe. Based on the column
density, we derive a lower-limit of a mass-loss rate to be M_dot ~ 0.015
(V_w/100 km/s) M_sun/yr, which roughly agrees with that inferred from the X-ray
luminosity, M_dot ~ 0.02 (V_w/100 km/s) M_sun/yr, where V_w is the
circumstellar wind speed. Such a high mass-loss rate suggests that the
progenitor star had eruptive mass ejections like a luminous blue variable star.
The total mass ejected in the eruptive period is estimated to be ~15 M_sun,
indicating that the progenitor mass is greater than ~25 M_sun.


title: Formal Verification of `Programming to Interfaces' Programs

abstract:
  This paper presents a formal approach to specify and verify object-oriented
programs written in the `programming to interfaces' paradigm. Besides the
methods to be invoked by its clients, an interface also declares a set of
abstract function/predicate symbols, together with a set of constraints on
these symbols. For each method declared in this interface, a specification
template is given using these abstract symbols. A class implementing this
interface can give its own definitions to the abstract symbols, as long as all
the constraints are satisfied. This class implements all the methods declared
in the interface such that the method specification templates declared in the
interface are satisfied w.r.t. the definitions of the abstract function symbols
in this class. Based on the constraints on the abstract symbols, the client
code using interfaces can be specified and verified precisely without knowing
what classes implement these interfaces. Given more information about the
implementing classes, the specifications of the client code can be specialized
into more precise ones without re-verifying the client code.
  Several commonly used interfaces and their implementations (including
Iterator, Observer, Comparable, and Comparator) are used to demonstrate that
the approach in this paper is both precise and flexible.


title: Public Key Infrastructure based on Authentication of Media Attestments

abstract:
  Many users would prefer the privacy of end-to-end encryption in their online
communications if it can be done without significant inconvenience. However,
because existing key distribution methods cannot be fully trusted enough for
automatic use, key management has remained a user problem. We propose a
fundamentally new approach to the key distribution problem by empowering
end-users with the capacity to independently verify the authenticity of public
keys using an additional media attestment. This permits client software to
automatically lookup public keys from a keyserver without trusting the
keyserver, because any attempted MITM attacks can be detected by end-users.
Thus, our protocol is designed to enable a new breed of messaging clients with
true end-to-end encryption built in, without the hassle of requiring users to
manually manage the public keys, that is verifiably secure against MITM
attacks, and does not require trusting any third parties.


title: Knowledge-Aided STAP Using Low Rank and Geometry Properties

abstract:
  This paper presents knowledge-aided space-time adaptive processing (KA-STAP)
algorithms that exploit the low-rank dominant clutter and the array geometry
properties (LRGP) for airborne radar applications. The core idea is to exploit
the fact that the clutter subspace is only determined by the space-time
steering vectors,
  {red}{where the Gram-Schmidt orthogonalization approach is employed to
compute the clutter subspace. Specifically, for a side-looking uniformly spaced
linear array, the} algorithm firstly selects a group of linearly independent
space-time steering vectors using LRGP that can represent the clutter subspace.
By performing the Gram-Schmidt orthogonalization procedure, the orthogonal
bases of the clutter subspace are obtained, followed by two approaches to
compute the STAP filter weights. To overcome the performance degradation caused
by the non-ideal effects, a KA-STAP algorithm that combines the covariance
matrix taper (CMT) is proposed. For practical applications, a reduced-dimension
version of the proposed KA-STAP algorithm is also developed. The simulation
results illustrate the effectiveness of our proposed algorithms, and show that
the proposed algorithms converge rapidly and provide a SINR improvement over
existing methods when using a very small number of snapshots.


title: Using Multiple Samples to Learn Mixture Models

abstract:
  In the mixture models problem it is assumed that there are $K$ distributions
$\theta_{1},\ldots,\theta_{K}$ and one gets to observe a sample from a mixture
of these distributions with unknown coefficients. The goal is to associate
instances with their generating distributions, or to identify the parameters of
the hidden distributions. In this work we make the assumption that we have
access to several samples drawn from the same $K$ underlying distributions, but
with different mixing weights. As with topic modeling, having multiple samples
is often a reasonable assumption. Instead of pooling the data into one sample,
we prove that it is possible to use the differences between the samples to
better recover the underlying structure. We present algorithms that recover the
underlying structure under milder assumptions than the current state of art
when either the dimensionality or the separation is high. The methods, when
applied to topic modeling, allow generalization to words not present in the
training data.


title: A supra-massive magnetar central engine for short GRB 130603B

abstract:
  We show that the peculiar early optical and in particular X-ray afterglow
emission of the short duration burst GRB 130603B can be explained by continuous
energy injection into the blastwave from a supra-massive magnetar central
engine. The observed energetics and temporal/spectral properties of the late
infrared bump (i.e., the "kilonova") are also found consistent with emission
from the ejecta launched during an NS-NS merger and powered by a magnetar
central engine. The isotropic-equivalent kinetic energies of both the GRB
blastwave and the kilonova are about $E_{\rm k}\sim 10^{51}$ erg, consistent
with being powered by a near-isotropic magnetar wind. However, this relatively
small value demands that most of the initial rotational energy of the magnetar
$(\sim {\rm a~ few \times 10^{52}~ erg})$ is carried away by gravitational wave
radiation. Our results suggest that (i) the progenitor of GRB 130603B would be
a NS-NS binary system, whose merger product would be a supra-massive neutron
star that lasted for about $\sim 1000$ seconds; (ii) the equation-of-state of
nuclear matter would be stiff enough to allow survival of a long-lived
supra-massive neutron star, so that it is promising to detect bright
electromagnetic counterparts of gravitational wave triggers without short GRB
associations in the upcoming Advanced LIGO/Virgo era.


title: A Novel Illumination-Invariant Loss for Monocular 3D Pose Estimation

abstract:
  The problem of identifying the 3D pose of a known object from a given 2D
image has important applications in Computer Vision. Our proposed method of
registering a 3D model of a known object on a given 2D photo of the object has
numerous advantages over existing methods. It does not require prior training,
knowledge of the camera parameters, explicit point correspondences or matching
features between the image and model. Unlike techniques that estimate a partial
3D pose (as in an overhead view of traffic or machine parts on a conveyor
belt), our method estimates the complete 3D pose of the object. It works on a
single static image from a given view under varying and unknown lighting
conditions. For this purpose we derive a novel illumination-invariant distance
measure between the 2D photo and projected 3D model, which is then minimised to
find the best pose parameters. Results for vehicle pose detection in real
photographs are presented.


title: Massive Gravity wrapped in the Cosmic Web

abstract:
  We study how the filamentary pattern of the cosmic web changes if the true
gravity deviates from the general relativity (GR) on the large scale. The f(R)
gravity whose strength is controlled to satisfy the current observational
constraints on the cluster scale is adopted as our fiducial model and a large
N-body simulation of high-resolution is utilized for this study. By applying
the minimal spanning tree algorithm to the halo catalogs from the simulation at
various epochs, we identify the main stems of the rich superclusters located in
the most prominent filamentary section of the cosmic web and determine their
spatial extents per member cluster as the degree of their straightness. It is
found that the $f(R)$ gravity has an effect of significantly bending the
superclusters and that the effect becomes stronger as the universe evolves.
Even in the case where the deviation from GR is too small to be detectable by
any other observables, the degree of the supercluster straightness exhibits
conspicuous difference between the $f(R)$ and the GR models. Our results also
imply that the supercluster straightness could be a useful discriminator of
f(R) gravity from the coupled dark energy since it is shown to evolve
differently between the two models. As a final conclusion, the degree of the
straightness of the rich superclusters should provide a powerful cosmological
test of large scale gravity.


title: Neutrino Events at IceCube and the Fermi Bubbles

abstract:
  We discuss the possibility that the IceCube neutrino telescope might be
observing the Fermi Bubbles. If the bubbles discovered in gamma rays originate
from accelerated protons, they should be strong emitters of high energy (> GeV)
neutrinos. These neutrinos are detectable as shower- or track-like events at a
Km^3 neutrino observatory. For a primary cosmic ray cutoff energy at or above
10 PeV, the Fermi Bubble flux substantially exceeds the atmospheric background,
and could account for up to ~ 4-5 of the 28 events detected above ~ 30 TeV at
IceCube. Running the detector for ~ 5-7 more years should be sufficient to
discover this flux at high significance. For a primary cosmic ray flux with
steeper spectrum, and/or lower cutoff energy, longer running times will be
required to overcome the background.


title: Very free curves on Fano Complete Intersections

abstract:
  In this paper, we show that general Fano complete intersections over an
algebraically closed field of arbitrary characteristics are separably
rationally connected. Our proof also implies that general log Fano complete
intersections with smooth tame boundary divisors admit very free $A^1$-curves.


title: Disintegration of graphene nanoribbons in large electrostatic fields

abstract:
  The deformation and disintegration of a graphene nanoribbon under external
electrostatic fields are investigated by first principle quantum mechanical
calculations to establish its stability range. The zigzag edges terminated by
various functional groups are considered. By analyzing the phonon spectrum, the
critical fracture field for each edge structure is obtained. It is found that
different terminal groups on the zigzag graphene nanoribbons lead to different
fracture patterns at different fracture fields. The failure mechanism is
demonstrated to rely on both the carbon bond alternation feature across the
ribbon and terminal group electronegativity.


title: A Curvature Flow Unifying Symplectic Curvature Flow And Pluriclosed Flow

abstract:
  Streets and Tian introduced pluriclosed flow and symplectic curvature flow in
recent years. Here we construct a curvature flow to unify these two flows. We
show the short time existence of our flow and exhibit an obstruction to long
time existence.


title:
Using pulsar timing arrays and the quantum normalization condition to
  constrain relic gravitational waves

abstract:
  In the non-standard model of relic gravitational waves (RGWs) generated in
the early universe, the theoretical spectrum of is mainly described by an
amplitude $r$ and a spectral index $\beta$, the latter usually being determined
by the slope of the inflation potential. Pulsar timing arrays (PTAs) data have
imposed constraints on the amplitude of strain spectrum for a power-law form as
a phenomenological model. Applying these constraints to a generic, theoretical
spectrum with $r$ and $\beta$ as independent parameters, we convert the PTAs
constraint into an upper bound on the index $\beta$, which turns out to be less
stringent than those upper bounds from BBN, CMB, and LIGO/VIRGO, respectively.
Moreover, it is found that PTAs constrain the non-standard RGWs more stringent
than the standard RGWs. If the condition of the quantum normalization is
imposed upon a theoretical spectrum of RGWs, $r$ and $\beta$ become related.
With this condition, a minimum requirement of the horizon size during inflation
is greater than the Planck length results in an upper bound on $\beta$, which
is comparable in magnitude to that by PTAs. When both PTAs and the quantum
normalization are applied to a theoretical spectrum of RGWs, constraints can be
obtained for other cosmic processes of the early universe, such as the
reheating, a process less understood observationally so far. The resulting
constraint is consistent with the slow-roll, massive scalar inflation model.
The future SKA will be able to constrain RGWs further and might even detect
RGWs, rendering an important probe to the very early universe.


title: Inversion of adjunction for rational and Du Bois pairs

abstract:
  We prove several results about the behavior Du Bois singularities and Du Bois
pairs in families. Some of these generalize existing statements about Du Bois
singularities to the pair setting while others are new even in the non-pair
setting. We also prove a new inversion of adjunction result for Du Bois and
rational pairs. In the non-pair setting this asserts that if a family over a
smooth base has a special fiber $X_0$ with Du Bois singularities and the
general fiber has rational singularities, then the total space has rational
singularities near $X_0$.


title: Real-time High Resolution Fusion of Depth Maps on GPU

abstract:
  A system for live high quality surface reconstruction using a single moving
depth camera on a commodity hardware is presented. High accuracy and real-time
frame rate is achieved by utilizing graphics hardware computing capabilities
via OpenCL and by using sparse data structure for volumetric surface
representation. Depth sensor pose is estimated by combining serial texture
registration algorithm with iterative closest points algorithm (ICP) aligning
obtained depth map to the estimated scene model. Aligned surface is then fused
into the scene. Kalman filter is used to improve fusion quality. Truncated
signed distance function (TSDF) stored as block-based sparse buffer is used to
represent surface. Use of sparse data structure greatly increases accuracy of
scanned surfaces and maximum scanning area. Traditional GPU implementation of
volumetric rendering and fusion algorithms were modified to exploit sparsity to
achieve desired performance. Incorporation of texture registration for sensor
pose estimation and Kalman filter for measurement integration improved accuracy
and robustness of scanning process.


title: Dalitz Plot Analysis of the $D^+\rightarrow K^0_S \pi^+ \pi^0$ Decay

abstract:
  We perform an analysis of the $D^+\rightarrow K^0_S \pi^+ \pi^0$ Dalitz plot
using a data set of 2.92 fb$^{-1}$ of $e^+e^-$ collisions at the $\psi(3770)$
accumulated by the BESIII Experiment, in which 166694 candidate events are
selected with a background of 15.1%. The Dalitz plot is found to be
well-represented by a combination of six quasi-two-body decay channels
($K^0_S\rho^+$, $K^0_S\rho(1450)^+$, $\overline{K}^{*0}\pi^+$,
$\overline{K}_0(1430)^0\pi^+$, $\overline{K}(1680)^0\pi^+$,
$\overline{\kappa}^0\pi^+$) plus a small non-resonant component. We also
consider a model-independent approach to confirm an obvious phase shift for the
$\overline{\kappa}\pi$ component. Using the fit fractions from this analysis,
partial branching ratios are updated with higher precision than previous
measurements.


title:
${B^0} - {{\bar B}^0}$ mixing in supersymmetry with gauged baryon and
  lepton numbers

abstract:
  We perform an analysis on ${B^0} - {{\bar B}^0}$ mixing in the extension of
the minimal supersymmetric standard model where baryon and lepton numbers are
local gauge symmetries (BLMSSM) by using the effective Hamiltonian method. And
the constraint of a 125 GeV Higgs to the parameter space has also been
consid-ered. The numerical results indicate that the contributions of the extra
particles can be sizeable in ${B^0} - {{\bar B}^0}$ mixing. For certain
parameter sets, the theoretical prediction of mass differences $\Delta m_{B}$
agrees with the current experimental result. Furthermore, ${B^0} - {{\bar
B}^0}$ mixing in the BLMSSM can preliminarily constrain the parameter space.
With the development of more precise theoretical analysis and experimental
determina-tions, the ${B^0} - {{\bar B}^0}$ mixing in the BLMSSM will have a
clearer picture and the parameter space in this model will also be further
constrained.


title: Non-trapping estimates near normally hyperbolic trapping

abstract:
  In this paper we prove semiclassical resolvent estimates for operators with
normally hyperbolic trapping which are lossless relative to non-trapping
estimates but take place in weaker function spaces. In particular, we obtain
non-trapping estimates in standard $L^2$ spaces for the resolvent sandwiched
between operators which localize away from the trapped set $\Gamma$ in a rather
weak sense, namely whose principal symbols vanish on $\Gamma$.


title:
ADMM Algorithm for Graphical Lasso with an $\ell_{\infty}$ Element-wise
  Norm Constraint

abstract:
  We consider the problem of Graphical lasso with an additional $\ell_{\infty}$
element-wise norm constraint on the precision matrix. This problem has
applications in high-dimensional covariance decomposition such as in
\citep{Janzamin-12}. We propose an ADMM algorithm to solve this problem. We
also use a continuation strategy on the penalty parameter to have a fast
implemenation of the algorithm.


title: An interview with Tsuyoshi Ando

abstract:
  In celebration of the distinguished achievements of Professor Tsuyoshi Ando
in matrix analysis and operator theory, we conducted an interview with him via
email. This paper presents Professor Ando's responses to several questions we
gave him regarding his education and life as a mathematician.


title:
Searching and Establishment of S-P-O Relationships for Linked RDF Graphs
  : An Adaptive Approach

abstract:
  In the coming era of semantic web linked data analysis is a very burning
issue for efficient searching and retrieval of information. One way of
establishing this link is to implement subject predicate object relationship
through Set Theory approach which is already done in our previous work. For
analyzing inter relationship between two RDF Graphs, RDF- Schema (RDFS) should
also be taken care of. In the present paper, an adaptive combination rule based
framework has been proposed for establishment of S P O relationship and RDF
Graph searching is reported. Hence the identification of criteria for
inter-relationship of RDF Graphs opens up new road in semantic search.


title: Theories of Hypergraph-Graph (HG(2)) Data Structure

abstract:
  Current paper introduces a Hypergraph Graph model of data storage which can
be represented as a hybrid data structure based on Hypergraph and Graph. The
pro-posed data structure is claimed to realize complex combinatorial
structures. The formal definition of the data structure is presented along with
the proper justification from real world scenarios. The paper reports some
elementary concepts of Hypergraph and presents theoretical aspects of the
proposed data structure including the concepts of Path, Cycle etc. The detailed
analysis of weighted HG 2 is presented along with discussions on Cost involved
with HG 2 paths.


title: Integrating RDF into Hypergraph-Graph (HG(2)) Data Structure

abstract:
  Current paper discusses the methodologies involved in integrating Resource
Description Framework into a HyperGraph Graph HG 2 data structure in order to
preserve the semantics of the information contained in RDF document for dealing
future cross platform information portability issues. The entire semantic web
is mostly dominated by few information frameworks like RDF, Topic Map, OWL etc.
Hence semantic web currently faces the problem of non existence of common
information meta-model which can integrate them all for ex-panded semantic
search. On the background of development of Hyper Graph Graph HG 2 data
structure, an RDF document if integrated to it, maintains the original
semantics and exposes some critical semantic and object mapping lift as well
which could further be exploited for semantic search and information
transitional problems. The focus of the paper is to present the mapping
constructs between RDF elements and HyperGraph Graph HG 2 elements.


title: Function Overloading Implementation in C++

abstract:
  In this article the function overloading in object-oriented programming is
elaborated and how they are implemented in C++. The language supports a variety
of programming styles. Here we are describing the polymorphism and its types in
brief. The main stress is given on the function overloading implementation
styles in the language. The polymorphic nature of languages has advantages like
that we can add new code without requiring changes to the other classes and
interfaces (in Java language) are easily implemented. In this technique, the
run-time overhead is also introduced in dynamic binding which increases the
execution time of the software. But there are no such types of overheads in
this static type of polymorphism because everything is resolved at the time of
compile time. Polymorphism; Function Overloading; Static Polymorphism;
Overloading; Compile Time Polymorphism.


title:
A Hybrid Web Recommendation System based on the Improved Association
  Rule Mining Algorithm

abstract:
  As the growing interest of web recommendation systems those are applied to
deliver customized data for their users, we started working on this system.
Generally the recommendation systems are divided into two major categories such
as collaborative recommendation system and content based recommendation system.
In case of collaborative recommen-dation systems, these try to seek out users
who share same tastes that of given user as well as recommends the websites
according to the liking given user. Whereas the content based recommendation
systems tries to recommend web sites similar to those web sites the user has
liked. In the recent research we found that the efficient technique based on
asso-ciation rule mining algorithm is proposed in order to solve the problem of
web page recommendation. Major problem of the same is that the web pages are
given equal importance. Here the importance of pages changes according to the
fre-quency of visiting the web page as well as amount of time user spends on
that page. Also recommendation of newly added web pages or the pages those are
not yet visited by users are not included in the recommendation set. To
over-come this problem, we have used the web usage log in the adaptive
association rule based web mining where the asso-ciation rules were applied to
personalization. This algorithm was purely based on the Apriori data mining
algorithm in order to generate the association rules. However this method also
suffers from some unavoidable drawbacks. In this paper we are presenting and
investigating the new approach based on weighted Association Rule Mining
Algorithm and text mining. This is improved algorithm which adds semantic
knowledge to the results, has more efficiency and hence gives better quality
and performances as compared to existing approaches.


title:
Fluctuation theorems for excess and housekeeping heats for underdamped
  systems

abstract:
  We present a simple derivation of the integral fluctuation theorems for
excess housekeeping heat for an underdamped Langevin system, without using the
concept of dual dynamics. In conformity with the earlier results, we find that
the fluctuation theorem for housekeeping heat holds when the steady state
distributions are symmetric in velocity, whereas there is no such requirement
for the excess heat. We first prove the integral fluctuation theorem for the
excess heat, and then show that it naturally leads to the integral fluctuation
theorem for housekeeping heat. We also derive the modified detailed fluctuation
theorems for the excess and housekeeping heats.


title:
Transition fronts for inhomogeneous monostable reaction-diffusion
  equations via linearization at zero

abstract:
  We prove existence of transition fronts for a large class of
reaction-diffusion equations in one dimension, with inhomogeneous monostable
reactions. We construct these as perturbations of corresponding front-like
solutions to the linearization of the PDE at $u=0$. While a close relationship
of the solutions to the two PDEs has been well known and exploited for KPP
reactions (and our method is an extension of such ideas from [15]), to the best
of our knowledge this is the first time such an approach has been used in the
construction and study of fronts for non-KPP monostable reactions.


title: Scaling laws in disk galaxies

abstract:
  A brief overview of several recent disk galaxy scaling relations is
presented, along with some historical background. In particular, after
introducing the (basic) radial light profiles of disk galaxies, I explain
several important `structural' scaling relations and review the latest
bulge-(black hole mass) diagrams. I go on to present the typical bulge-to-disk
flux ratios of disk galaxies and suggest the use of a grid of bulge-to-disk
flux ratio versus disk Hubble type - based on the nature of the spiral arms -
to complement the Hubble-Jeans sequence. I then briefly mention pure disk
galaxies before cautioning on difficulties with identifying pseudo-bulges built
from secular evolution. Finally, I conclude by discussing a likely connection
between modern day bulges in disk galaxies and high-redshift (z ~ 2+/-0.5)
compact galaxies which may have since acquired a disk via cold flows and
quiescent accretion.


title: A New Avenue to Charged Higgs Discovery in Multi-Higgs Models

abstract:
  Current searches for the charged Higgs at the LHC focus only on the
$\tau\nu$, $cs$, and $tb$ final states. Instead, we consider the process $pp\to
\Phi\to W^\pm H^\mp \to W^+ W^- A$ where $\Phi$ is a heavy neutral Higgs boson,
$H^\pm$ is a charged Higgs boson, and $A$ is a light Higgs boson, with mass
either below or above the $b\bar{b}$ threshold. The cross-section for this
process is typically large when kinematically open since $H^\pm \to W^\pm A$
can be the dominant decay mode of the charged Higgs. The final state we
consider has two leptons and missing energy from the doubly leptonic decay of
the $W^+ W^-$ and possibly additional jets; it is therefore constrained by
existing SM Higgs searches in the $W^+ W^-$ channel. We extract these
constraints on the cross-section for this process as a function of the masses
of the particles involved. We also apply our results specifically to a type-II
two Higgs doublet model with an extra Standard-Model-singlet and obtain new and
powerful constraints on $m_{H^\pm}$ and $\tan\beta$. We point out that a
slightly modified version of this search, with more dedicated cuts, could be
used to possibly discover the charged Higgs, either with existing data or in
the future.


title: A new geometrical approach to void statistics

abstract:
  Modelling cosmic voids as spheres in Euclidean space, the notion of a
de-Sitter configuration space is introduced. It is shown that a uniform
distribution over this configuration space yields a power-law approximating the
void size distribution in an intermediate range of volumes, as well as an
estimate for the fractal dimension of the large scale structure.


title: QoS Based Framework for Effective Web Services in Cloud Computing

abstract:
  Enhancements in technology always follow Consumer requirements. Consumer
requires best of service with least possible mismatch and on time. Numerous
applications available today are based on Web Services and Cloud Computing.
Recently, there exist many Web Services with similar functional
characteristics. Choosing a right Service from group of similar Web Service is
a complicated task for Service Consumer. In that case, Service Consumer can
discover the required Web Service using non functional attributes of the Web
Services such as QoS. Proposed layered architecture and Web Service Cloud
i.e.WS Cloud computing Framework synthesizes the Non functional attributes that
includes reliability, availability, response time, latency etc. The Service
Consumer is projected to provide the QoS requirements as part of Service
discovery query. This framework will discover and filter the Web Services form
the cloud and rank them according to Service Consumer preferences to facilitate
Service on time.


title: Random Field XY Model in Three Dimensions

abstract:
  We study random-field xy spin model at T=0 numerically on lattices of up to
1000 x 1000 x 1000 spins with the accent on the weak random field. Our
numerical method is physically equivalent to slow cooling in which the system
is gradually losing the energy and relaxing to an energy minimum. The system
shows glass properties, the resulting spin states depending strongly on the
initial conditions. Random initial condition for the spins leads to the vortex
glass (VG) state with short-range spin-spin correlations defined by the average
distance between vortex lines. Collinear and some other vortex-free initial
conditions result in the vortex-free ferromagnetic (F) states that have a lower
energy. The energy difference between the F and VG states correlates with
vorticity of the VG state. Correlation functions in the F states agree with the
Larkin-Imry-Ma theory at short distances. Hysteresis curves for weak random
field are dominated by topologically stable spin walls raptured by vortex
loops. We find no relaxation paths from the F, VG, or any other states to the
hypothetical vortex-free state with zero magnetization.


title:
Raman spectra of electrochemically hydrogenated diamond like carbon
  surface

abstract:
  Raman spectroscopy has been employed to distinguish between the Raman
spectrum of pristine hydrogenated diamond like carbon (PHDLC) and that of
electrochemically hydrogenated diamond like carbon (ECHDLC). The enhancement of
the background photoluminescence (PL) in the Raman spectrum and broadening of
PL spectrum of ECHDLC are identified to be due to increase of sp3 C-H density
onto the PHDLC surface, during novel electrochemical process of hydrogenation
of sp2 C=C into sp3 C-H.


title:
Finding a Maximum Clique using Ant Colony Optimization and Particle
  Swarm Optimization in Social Networks

abstract:
  Interaction between users in online social networks plays a key role in
social network analysis. One on important types of social group is full
connected relation between some users, which known as clique structure.
Therefore finding a maximum clique is essential for some analysis. In this
paper, we proposed a new method using ant colony optimization algorithm and
particle swarm optimization algorithm. In the proposed method, in order to
attain better results, it is improved process of pheromone update by particle
swarm optimization. Simulation results on popular standard social network
benchmarks in comparison standard ant colony optimization algorithm are shown a
relative enhancement of proposed algorithm.


title:
Disorder effects on thermal transport on the surface of topological
  superconductors by the self-consistent Born approximation

abstract:
  We have studied the longitudinal thermal conductivity of the surface of a
three-dimensional time-reversal symmetric topological superconductor with
random disorder. Majorana fermions on the surface of topological
superconductors have a response to the gravitational field, which is realized
as a thermal response to the temperature gradient inside of the material.
Because of the presence of both time-reversal symmetry and particle-hole
symmetry, disorder on the surface emerges in the Hamiltonian only as spatial
deformations of the pair potential. In terms of the gravitational field, the
disorder results in spatial fluctuations of the metric. We consider disorder
effects on the thermal conductivity perturbatively within the self-consistent
Born approximation. The density of states is calculated with the Green's
function technique and the thermal conductivity of the surface modes is derived
through the electronic conductivity using Wiedemann-Franz law for the Majorana
fermions.


title: Solving Minimum Vertex Cover Problem Using Learning Automata

abstract:
  Minimum vertex cover problem is an NP-Hard problem with the aim of finding
minimum number of vertices to cover graph. In this paper, a learning automaton
based algorithm is proposed to find minimum vertex cover in graph. In the
proposed algorithm, each vertex of graph is equipped with a learning automaton
that has two actions in the candidate or non-candidate of the corresponding
vertex cover set. Due to characteristics of learning automata, this algorithm
significantly reduces the number of covering vertices of graph. The proposed
algorithm based on learning automata iteratively minimize the candidate vertex
cover through the update its action probability. As the proposed algorithm
proceeds, a candidate solution nears to optimal solution of the minimum vertex
cover problem. In order to evaluate the proposed algorithm, several experiments
conducted on DIMACS dataset which compared to conventional methods.
Experimental results show the major superiority of the proposed algorithm over
the other methods.


title: A Method for Calculating Collision Probability Between Space Objects

abstract:
  A method is developed to calculate collision probability in this paper. Based
on the encounter geometric features of space objects, it is reasonable to
separate the radial orbital motions from that in the cross section for most
encounter events in near circular orbit. Therefore, the collision probability
caused by orbit altitude difference in the radial direction and the collision
probability caused by arrival time difference in the cross section are
calculated respectively. The net collision probability is expressed as an
explicit expression by multiplying the above two components. Numerical cases
are applied to test this method by comparing the results with the general
method. The results indicate that this method is valid for most near circular
orbital encounter events.


title:
Detecting Anomalous Activity on Networks with the Graph Fourier Scan
  Statistic

abstract:
  We consider the problem of deciding, based on a single noisy measurement at
each vertex of a given graph, whether the underlying unknown signal is constant
over the graph or there exists a cluster of vertices with anomalous activation.
This problem is relevant to several applications such as surveillance, disease
outbreak detection, biomedical imaging, environmental monitoring, etc. Since
the activations in these problems often tend to be localized to small groups of
vertices in the graphs, we model such activity by a class of signals that are
supported over a (possibly disconnected) cluster with low cut size relative to
its size. We analyze the corresponding generalized likelihood ratio (GLR)
statistics and relate it to the problem of finding a sparsest cut in the graph.
We develop a tractable relaxation of the GLR statistic based on the
combinatorial Laplacian of the graph, which we call the graph Fourier scan
statistic, and analyze its properties. We show how its performance as a testing
procedure depends directly on the spectrum of the graph, and use this result to
explicitly derive its asymptotic properties on a few significant graph
topologies. Finally, we demonstrate theoretically and with simulations that the
graph Fourier scan statistic can outperform naive testing procedures based on
global averaging and vertex-wise thresholding. We also demonstrate the
usefulness of the GFSS by analyzing groundwater Arsenic concentrations from a
U.S. Geological Survey dataset.


title: N=1 Super-symmetry Lagrangian in the de Sitter space

abstract:
  Previously, Pahlavan, Rouhani and Takook have introduced a novel $N=1$
super-symmetric algebra in de Sitter space-time. This paper is an attempt to
build a proper $N=1$ super-symmetric field theory of classical level in the de
Sitter space. The generators, gauge transformations and different fields in a
5-dimensional ambient space notation are defined and corresponding super-space
and super-fields are introduced. Finally, the $N=1$ super-symmetry Lagrangian
in the de Sitter ambient space notation has been derived.


title:
Partitioning Clustering algorithms for handling numerical and
  categorical data: a review

abstract:
  Clustering is widely used in different field such as biology, psychology, and
economics. Most traditional clustering algorithms are limited to handling
datasets that contain either numeric or categorical attributes. However,
datasets with mixed types of attributes are common in real life data mining
applications. In this paper, we review partitioning based algorithm such as
K-prototype, Extension of K-prototype, K-histogram, Fuzzy approaches, genetic
approaches, etc. These algorithm works on both numerical and categorical data.
The approaches has been proposed to handle mixed data are based on four
different perceptive: i) split data set into two part such that each part
contain either numerical or categorical data, then apply separate clustering
algorithm on each data set, finally combined the result of both clustering
algorithm, ii) converting categorical attribute into numerical attribute and
apply numerical attribute clustering algorithm; iii) discrimination of
numerical attribute and apply categorical based clustering algorithm; iv)
Conversion of the categorical attributes into binary ones and apply any
numerical based clustering algorithm


title: Physics with Trapped Charged Particles

abstract:
  Ion traps, which were first introduced in the late 1950s and early 1960s,
have established themselves as indispensable tools in many areas of physics,
chemistry and technology. This chapter gives a brief survey of the operating
principles and development of ion traps, together with a short description of
how ions are loaded and detected. This is followed by a brief account of some
of the current applications of ion traps.


title: Eigenvalue asymptotics for Schr\"odinger operators on sparse graphs

abstract:
  We consider Schr\"odinger operators on sparse graphs. The geometric
definition of sparseness turn out to be equivalent to a functional inequality
for the Laplacian. In consequence, sparseness has in turn strong spectral and
functional analytic consequences. Specifically, one consequence is that it
allows to completely describe the form domain. Moreover, as another consequence
it leads to a characterization for discreteness of the spectrum. In this case
we determine the first order of the corresponding eigenvalue asymptotics.


title:
Thermodynamics of five-dimensional static three-charge STU black holes
  with squashed horizons

abstract:
  We present a new expression for the five-dimensional static Kaluza-Klein
black hole solution with squashed $S^3$ horizons and three different charge
parameters. This black hole solution belongs to $D = 5$ $N = 2$ supergravity
theory, its spacetime is locally asymptotically flat and has a spatial infinity
$R \times S^1 \hookrightarrow S^2$. The form of the solution is extraordinary
simple and permits us very conveniently to calculate its conserved charges by
using the counterterm method. It is further shown that our thermodynamical
quantities perfectly obey both the differential and the integral first laws of
black hole thermodynamics if the length of the compact extra-dimension can be
viewed as a thermodynamical variable.


title:
Experimental evidence for non-axisymmetric magnetorotational instability
  in a rotating liquid metal exposed to an azimuthal magnetic field

abstract:
  The azimuthal version of the magnetorotational instability (MRI) is a
non-axisymmetric instability of a hydrodynamically stable differentially
rotating flow under the influence of a purely or predominantly azimuthal
magnetic field. It may be of considerable importance for destabilizing
accretion disks, and plays a central role in the concept of the MRI dynamo. We
report the results of a liquid metal Taylor-Couette experiment that shows the
occurrence of an azimuthal MRI in the expected range of Hartmann numbers.


title:
Predicting the steady state thickness of passive films with the Point
  Defect Model in fretting corrosion experiments

abstract:
  Some implants have approximately a lifetime of 15 years. The femoral stem,
for example, should be made of 316L/316LN stainless steel. Fretting corrosion,
friction under small displacements, should occur during human gait, due to
repeated loadings and un-loadings, between stainless steel and bone for
instance. Some experimental investigations of fretting corrosion have been
practiced. As well known, metallic alloys and especially stainless steels are
covered with a passive film that prevents from the corrosion and degradation.
This passive layer of few nanometers, at ambient temperature, is the key of our
civilization according to some authors. This work is dedicated to predict the
passive layer thicknesses of stainless steel under fretting corrosion with a
specific emphasis on the role of proteins. The model is based on the Point
Defect Model (micro scale) and an update of the model on the friction process
(micro-macro scale). Genetic algorithm was used for finding solution of the
problem. The major results are, as expected from experimental results, albumin
prevents from degradation at the lowest concentration of chlorides; an
incubation time is necessary for degrading the passive film; under fretting
corrosion and high concentration of chlorides the passive behavior is
annihilated.
  Les implants orthop\'ediques de hanche ont une dur\'ee de vie d'environ 15
ans. Par exemple, la tige f\'emorale d'un tel implant peut \^etre r\'ealis\'ee
en acier inoxydable 316L ou 316LN. Le fretting corrosion, frottement sous
petits d\'eplacements, peut se produire pendant la marche humaine en raison des
chargements r\'ep\'et\'es entre le m\'etal de la proth\`ese et l'os. Plusieurs
investigations exp\'erimentales du fretting corrosion ont \'et\'e entreprises.
Cette couche passive de quelques nanom\`etres, \`a temp\'erature ambiante, est
le point clef sur lequel repose le d\'eveloppement de notre civilisation, selon
certains auteurs. Ce travail vise \`a pr\'edire les \'epaisseurs de cette
couche passive de l'acier inoxydable soumis au fretting corrosion, avec une
attention sp\'ecifique sur le r\^ole des prot\'eines. Le mod\`ele utilis\'e est
bas\'e sur le Point Defect Model, PDM (\`a une \'echelle microscopique) et une
am\'elioration de ce mod\`ele en prenant en compte le processus de frottement
sous petits d\'ebattements. L'algorithme g\'en\'etique a \'et\'e utilis\'e pour
optimiser la convergence du probl\`eme. Les r\'esultats les plus importants
sont, comme d\'emontr\'e avec les essais exp\'erimentaux, que l'albumine, la
prot\'eine \'etudi\'ee, emp\^eche les d\'egradations de l'acier inoxydable aux
plus faibles concentrations d'ions chlorure ; ensuite, aux plus fortes
concentrations de chlorures, un temps d'incubation est n\'ecessaire pour
d\'etruire le film passif.


title:
Link Quality Control Mechanism for Selective and Opportunistic AF
  Relaying in Cooperative ARQs: A MLSD Perspective

abstract:
  Incorporating relaying techniques into Automatic Repeat reQuest (ARQ)
mechanisms gives a general impression of diversity and throughput enhancements.
Allowing overhearing among multiple relays is also a known approach to increase
the number of participating relays in ARQs. However, when opportunistic
amplify-and-forward (AF) relaying is applied to cooperative ARQs, the system
design becomes nontrivial and even involved. Based on outage analysis, the
spatial and temporal diversities are first found sensitive to the received
signal qualities of relays, and a link quality control mechanism is then
developed to prescreen candidate relays in order to explore the diversity of
cooperative ARQs with a selective and opportunistic AF (SOAF) relaying method.
According to the analysis, the temporal and spatial diversities can be fully
exploited if proper thresholds are set for each hop along the relaying routes.
The SOAF relaying method is further examined from a packet delivery viewpoint.
By the principle of the maximum likelihood sequence detection (MLSD),
sufficient conditions on the link quality are established for the proposed
SOAF-relaying-based ARQ scheme to attain its potential diversity order in the
packet error rates (PERs) of MLSD. The conditions depend on the minimum
codeword distance and the average signal-to-noise ratio (SNR). Furthermore,
from a heuristic viewpoint, we also develop a threshold searching algorithm for
the proposed SOAF relaying and link quality method to exploit both the
diversity and the SNR gains in PER. The effectiveness of the proposed
thresholding mechanism is verified via simulations with trellis codes.


abstract:
  Scattering lengths for two pseudoscalar meson systems, $\pi\pi(I=2)$,
$KK(I=1)$ and $\pi K(I=3/2,\ 1/2)$, are calculated from lattice QCD by using
the finite size formula. We perform the calculation with $N_f=2+1$ gauge
configurations generated on $32^3 \times 64$ lattice using the Iwasaki gauge
action and non-perturbatively ${\cal O}(a)$-improved Wilson action at $a^{-1} =
2.19$ GeV. The quark masses correspond to $m_\pi = 0.17 - 0.71$ GeV. For $\pi
K(I=1/2)$ system, we use the variational method with the two operators,
$\bar{s}u$ and $\pi K$, to separate the contamination from the higher states.
In order to obtain the scattering length at the physical quark mass, we fit our
results at the several quark masses with the formula of the ${\cal O}(p^4)$
chiral perturbation theory (ChPT) and that including the effects of the
discretization error from the Wilson fermion, Wilson chiral perturbation theory
(WChPT). We found that the mass dependence of our results near $m_\pi=0.17$ GeV
are described well by WChPT but not by ChPT. The scattering lengths at the
physical point are given as $a_0^{(2)} m_\pi =-0.04243(22)(43)$, $a_0^{(1)} m_K
=-0.312(17)(31)$, $a_0^{(3/2)}\mu_{\pi K}=-0.0477(27)(20)$ and
$a_0^{(1/2)}\mu_{\pi K}=0.150(16)(37)$. Possible systematic errors are also
discussed.


title: A superasymptotic formula for the number of plane partitions

abstract:
  We revisit a formula for the number of plane partitions due to Almkvist.
Using the circle method, we provide modifications to his formula along with
estimates of the errors. We show that the improved formula continues to be an
asymptotic series. Nevertheless, an optimal truncation (i.e., superasymptotic)
of the formula provides exact numbers of plane partitions for all positive
integers n <6400 and numbers with estimated errors for larger values. For
instance, the formula correctly reproduces 305 of the 316 digits of the numbers
of plane partitions of 6999 as predicted by the estimated error. We believe
that an hyperasymptotic truncation might lead to exact numbers for positive
integers up to 50000.


title:
A curious polynomial interpolation of Carlitz-Riordan's $q$-ballot
  numbers

abstract:
  We study a polynomial sequence $C_n(x|q)$ defined as a solution of a
$q$-difference equation. This sequence, evaluated at $q$-integers, interpolates
Carlitz-Riordan's $q$-ballot numbers. In the basis given by some kind of
$q$-binomial coefficients, the coefficients are again some $q$-ballot numbers.
We obtain in a combinatorial way another curious recurrence relation for these
polynomials.


title: Hierarchies

abstract:
  We study the complexity theory for the local distributed setting introduced
by Korman, Peleg and Fraigniaud. They have defined three complexity classes LD
(Local Decision), NLD (Nondeterministic Local Decision) and NLD^#n. The class
LD consists of all languages which can be decided with a constant number of
communication rounds. The class NLD consists of all languages which can be
verified by a nondeterministic algorithm with a constant number of
communication rounds. In order to define the nondeterministic classes, they
have transferred the notation of nondeterminism into the distributed setting by
the use of certificates and verifiers. The class NLD^#n consists of all
languages which can be verified by a nondeterministic algorithm where each node
has access to an oracle for the number of nodes. They have shown the hierarchy
LD subset NLD subset NLD^#n.
  Our main contributions are strict hierarchies within the classes defined by
Korman, Peleg and Fraigniaud. We define additional complexity classes: the
class LD(t) consists of all languages which can be decided with at most t
communication rounds. The class NLD-O(f) consists of all languages which can be
verified by a local verifier such that the size of the certificates that are
needed to verify the language are bounded by a function from O(f). Our main
results are refined strict hierarchies within these nondeterministic classes.


title: Kinetic equations: computation

abstract:
  Kinetic equations bridge the gap between a microscopic description and a
macroscopic description of the physical reality. Due to the high dimensionality
the construction of numerical methods represents a challenge and requires a
careful balance between accuracy and computational complexity.


title:
Pulsar timing residuals due to individual non-evolving gravitational
  wave sources

abstract:
  The pulsar timing residuals induced by gravitational waves from non-evolving
single binary sources are affected by many parameters related to the relative
positions of the pulsar and the gravitational wave sources. We will fully
analyze the effects due to different parameters one by one. The standard
deviations of the timing residuals will be calculated with a variable parameter
fixing a set of other parameters. The orbits of the binary sources will be
generally assumed to be elliptical. The influences of different eccentricities
on the pulsar timing residuals will also studied in detail. We find that
effects of the related parameters are quite different, and some of them present
certain regularities.


title: Random fixed point theorems under mild continuity assumptions

abstract:
  In this paper, we study the existence of the random fixed points under mild
continuity assumptions. The main theorems consider the almost lower
semicontinuous operators defined on Frechet spaces and also operators having
properties weaker than lower semicontinuity. Our results either extend or
improve corresponding ones present in literature.


title:
Commutants of Toeplitz operators with radial symbols on the Fock-Sobolev
  space

abstract:
  In the setting of the Fock space over the complex plane, Bauer and Lee have
recently characterized commutants of Toeplitz operators with radial symbols,
under the assumption that symbols have at most polynomial growth at infinity.
Their characterization states: If one of the symbols of two commuting Toeplitz
operators is nonconstant and radial, then the other must be also radial. We
extend this result to the Fock-Sobolev spaces.


title:
Baryon chiral perturbation theory with Wilson fermions up to
  $\mathcal{O}(a^2)$ and discretization effects of latest $n_f=2+1$ LQCD octet
  baryon masses

abstract:
  We construct the chiral Lagrangians relevant in studies of the ground-state
octet baryon masses up to $\mathcal{O}(a^2)$ by taking into account
discretization effects and calculate the masses up to $\mathcal{O}(p^4)$ in the
extended-on-mass-shell scheme. As an application, we study the latest $n_f=2+1$
LQCD data on the ground-state octet baryon masses from the PACS-CS,
QCDSF-UKQCD, HSC, and NPLQCD Collaborations. It is shown that the
discretization effects for the studied LQCD simulations are at the order of one
to two percent for lattice spacings up to $0.15$ fm and the pion mass up to 500
MeV.


title: Downscaling of global solar irradiation in R

abstract:
  A methodology for downscaling solar irradiation from satellite-derived
databases is described using R software. Different packages such as raster,
parallel, solaR, gstat, sp and rasterVis are considered in this study for
improving solar resource estimation in areas with complex topography, in which
downscaling is a very useful tool for reducing inherent deviations in
satellite-derived irradiation databases, which lack of high global spatial
resolution. A topographical analysis of horizon blocking and sky-view is
developed with a digital elevation model to determine what fraction of hourly
solar irradiation reaches the Earth's surface. Eventually, kriging with
external drift is applied for a better estimation of solar irradiation
throughout the region analyzed. This methodology has been implemented as an
example within the region of La Rioja in northern Spain, and the mean absolute
error found is a striking 25.5% lower than with the original database.


title: Active Linkability Attacks

abstract:
  We study linking attacks on communication protocols. We show that an active
attacker is strictly more powerful in this setting than previously-considered
passive attackers. We introduce a formal model to reason about active
linkability attacks, formally define security against these attacks and give
very general conditions for both security and insecurity of protocols. In
addition, we introduce a composition-like technique that allows to obtain
security proofs by only studying small components of a protocol.


title:
Beamforming for MISO Interference Channels with QoS and RF Energy
  Transfer

abstract:
  We consider a multiuser multiple-input single-output interference channel
where the receivers are characterized by both quality-of-service (QoS) and
radio-frequency (RF) energy harvesting (EH) constraints. We consider the power
splitting RF-EH technique where each receiver divides the received signal into
two parts a) for information decoding and b) for battery charging. The minimum
required power that supports both the QoS and the RF-EH constraints is
formulated as an optimization problem that incorporates the transmitted power
and the beamforming design at each transmitter as well as the power splitting
ratio at each receiver. We consider both the cases of fixed beamforming and
when the beamforming design is incorporated into the optimization problem. For
fixed beamforming we study three standard beamforming schemes, the zero-forcing
(ZF), the regularized zero-forcing (RZF) and the maximum ratio transmission
(MRT); a hybrid scheme, MRT-ZF, comprised of a linear combination of MRT and ZF
beamforming is also examined. The optimal solution for ZF beamforming is
derived in closed-form, while optimization algorithms based on second-order
cone programming are developed for MRT, RZF and MRT-ZF beamforming to solve the
problem. In addition, the joint-optimization of beamforming and power
allocation is studied using semidefinite programming (SDP) with the aid of rank
relaxation.


title:
A Combinatorial Formula for Principal Minors of a Matrix with
  Tree-metric Exponents and Its Applications

abstract:
  Let $T$ be a tree with a vertex set $\{ 1,2,\dots, N \}$. Denote by $d_{ij}$
the distance between vertices $i$ and $j$. In this paper, we present an
explicit combinatorial formula of principal minors of the matrix
$(t^{d_{ij}})$, and its applications to tropical geometry, study of
multivariate stable polynomials, and representation of valuated matroids. We
also give an analogous formula for a skew-symmetric matrix associated with $T$.


title:
Multiple-relaxation-time lattice Boltzmann modeling of incompressible
  flows in porous media

abstract:
  In this paper, a two-dimensional eight-velocity (D2Q8)
multiple-relaxation-time (MRT) lattice Boltzmann (LB) model is proposed for
incompressible porous flows at the representative elementary volume scale based
on the Brinkman-Forchheimer-extended Darcy formulation. In the model, the
porosity is included into the pressure-based equilibrium moments, and the
linear and nonlinear drag forces of the porous media are incorporated into the
model by adding a forcing term to the MRT-LB equation in the moment space.
Through the Chapman-Enskog analysis, the generalized Navier-Stokes equations
can be recovered exactly without artificial compressible errors. Numerical
simulations of several typical two-dimensional porous flows are carried out to
validate the present MRT-LB model. The numerical results of the present MRT-LB
model are in good agreement with the analytical solutions and/or other
numerical solutions reported in the literature.


title: Diphoton plus $Z$ production at the ILC at ${\cal O}(\alpha^4)$

abstract:
  Precision measurement for the production of a $Z$-boson in association with
two photons is important for investigating the Higgs boson and exploring new
physics at the International Linear Collider. It could be used to study the
$ZZ\gamma\gamma$ anomalous quartic gauge coupling. In this work we report on
our calculation of the full ${\cal O} (\alpha^4)$ contributions to the $e^+e^-
\to Z \gamma\gamma $ process in the standard model, and we analyze the
electroweak (EW) quantum effects on the total cross section. We investigate the
dependence of the $Z\gamma\gamma$ production rate on the event selection scheme
and provide distributions for some important kinematic observables. We find
that the next-to-leading order (NLO) EW corrections can enhance the total cross
section quantitatively from $2.32\%$ to $9.61\%$ when the colliding energy goes
up from $250 GeV$ to $1 TeV$, and the NLO EW corrections show obviously a non
trivial phase space dependence. We conclude that in studying the signal process
$e^+e^- \to ZH \to Z \gamma\gamma $, the background process $e^+e^- \to Z
\gamma\gamma $ can be suppressed significantly if we take appropriate kinematic
cuts on the final products.


title: The homogeneous steady state of a confined granular gas

abstract:
  The non-equilibrium statistical mechanics and kinetic theory for a model of a
confined quasi-two-dimensional gas of inelastic hard spheres is presented. The
dynamics of the particles includes an effective mechanism to transfer the
energy injected in the vertical direction to the horizontal degrees of freedom.
The Enskog approximation is formulated and used as the basis to investigate the
temperature and the distribution function of the steady state eventually
reached by the system. An exact scaling of the distribution function of the
system having implications on the form of its moments is pointed out. The
theoretical predictions are compared with numerical results obtained by a
particle simulation method, and a good agreement is found.


title: Programming with Permissions in Mezzo

abstract:
  We present Mezzo, a typed programming language of ML lineage. Mezzo is
equipped with a novel static discipline of duplicable and affine permissions,
which controls aliasing and ownership. This rules out certain mistakes,
including representation exposure and data races, and enables new idioms, such
as gradual initialization, memory re-use, and (type)state changes. Although the
core static discipline disallows sharing a mutable data structure, Mezzo offers
several ways of working around this restriction, including a novel dynamic
ownership control mechanism which we dub "adoption and abandon".


title:
On the boundary conditions in deformed quantum mechanics with minimal
  length uncertainty

abstract:
  We find the coordinate space wave functions, maximal localization states, and
quasiposition wave functions in a GUP framework that implies a minimal length
uncertainty using a formally self-adjoint representation. We show that how the
boundary conditions in quasiposition space can be exactly determined from the
boundary conditions in coordinate space.


title:
Assessing lack of common support in causal inference using Bayesian
  nonparametrics: Implications for evaluating the effect of breastfeeding on
  children's cognitive outcomes

abstract:
  Causal inference in observational studies typically requires making
comparisons between groups that are dissimilar. For instance, researchers
investigating the role of a prolonged duration of breastfeeding on child
outcomes may be forced to make comparisons between women with substantially
different characteristics on average. In the extreme there may exist
neighborhoods of the covariate space where there are not sufficient numbers of
both groups of women (those who breastfed for prolonged periods and those who
did not) to make inferences about those women. This is referred to as lack of
common support. Problems can arise when we try to estimate causal effects for
units that lack common support, thus we may want to avoid inference for such
units. If ignorability is satisfied with respect to a set of potential
confounders, then identifying whether, or for which units, the common support
assumption holds is an empirical question. However, in the high-dimensional
covariate space often required to satisfy ignorability such identification may
not be trivial. Existing methods used to address this problem often require
reliance on parametric assumptions and most, if not all, ignore the information
embedded in the response variable. We distinguish between the concepts of
"common support" and common causal support." We propose a new approach for
identifying common causal support that addresses some of the shortcomings of
existing methods. We motivate and illustrate the approach using data from the
National Longitudinal Survey of Youth to estimate the effect of breastfeeding
at least nine months on reading and math achievement scores at age five or six.
We also evaluate the comparative performance of this method in hypothetical
examples and simulations where the true treatment effect is known.


title:
Multiuser Broadcast Erasure Channel with Feedback and Side Information,
  and Related Index Coding Results

abstract:
  We consider the N-user broadcast erasure channel with public feedback and
side information. Before the beginning of transmission, each receiver knows a
function of the messages of some of the other receivers. This situation arises
naturally in wireless and in particular cognitive networks where a node may
overhear transmitted messages destined to other nodes before transmission over
a given broadcast channel begins. We provide an upper bound to the capacity
region of this system. Furthermore, when the side information is linear, we
show that the bound is tight for the case of two-user broadcast channels. The
special case where each user knows the whole or nothing of the message of each
other node, constitutes a generalization of the index coding problem. For this
instance, and when there are no channel errors, we show that the bound reduces
to the known Maximum Weighted Acyclic Induced Subgraph bound. We also show how
to convert the capacity upper bound to transmission completion rate (broadcast
rate) lower bound and provide examples of codes for certain information graphs
for which the bound is either achieved of closely approximated


title:
Study of the properties of Cosmic rays and solar X-Ray Flares by balloon
  borne experiments

abstract:
  Indian Centre for Space Physics is engaged in pioneering balloon borne
experiments with typical payloads less than ~ 3.5kg. Low cost rubber balloons
are used to fly them to a height of about 40km. In a double balloon system, the
booster balloon lifts the orbiter balloon to its cruising altitude where data
is taken for a longer period of time. In this Paper, we present our first
scientific report on the variation of Cosmic Rays and muons with altitude and
detection of several solar flares in X-rays between 20keV and 100keV. We found
the altitude of the Pfotzer maximum at Tropic of Cancer for cosmic rays and
muons and catch several solar flares in hard X-rays. We find that the hard
X-ray (> 40keV) sky becomes very transparent above Pfotzer maximum. We find the
flare spectrum to have a power-law distribution. From these studies, we infer
that valuable scientific research could be carried out in near space using low
cost balloon borne experiments. Published in Online version of Indian Journal
of Physics.


title:
Direct Measurement of Competing Quantum Effects on the Kinetic Energy of
  Heavy Water upon Melting

abstract:
  Even at room temperature, quantum mechanics plays a major role in determining
the quantitative behaviour of light nuclei, changing significantly the values
of physical properties such as the heat capacity. However, other observables
appear to be only weakly affected by nuclear quantum effects (NQEs): for
instance, the melting temperatures of light and heavy water differ by less than
4 K. Recent theoretical work has attributed this to a competition between intra
and inter molecular NQEs, which can be separated by computing the anisotropy of
the quantum kinetic energy tensor. The principal values of this tensor change
in opposite directions when ice melts, leading to a very small net quantum
mechanical effect on the melting point. This paper presents the first direct
experimental observation of this phenomenon, achieved by measuring the
deuterium momentum distributions n(p) in heavy water and ice using Deep
Inelastic Neutron Scattering (DINS), and resolving their anisotropy. Results
from the experiments, supplemented by a theoretical analysis, show that the
anisotropy of the quantum kinetic energy tensor can also be captured for
heavier atoms such as oxygen.


title: QCD symmetries in eta and etaprime mesic nuclei

abstract:
  We discuss the role of QCD symmetries and confinement in understanding eta
and etaprime mesic nuclei. Eta and etaprime bound states in nuclei are
sensitive to the flavour-singlet component in the meson. The bigger the singlet
component, the more attraction and the greater the binding. Recent results on
the etaprime mass in nuclei from the CBELSA/TAPS collaboration are very similar
to the prediction of the Quark Meson Coupling model. In the model eta-etaprime
mixing induces a factor of two enhancement of the eta-nucleon scattering length
relative to the prediction with a pure octet eta, with real part about 0.8 fm.


title: From supernovae to neutron stars

abstract:
  The gravitational collapse, bounce, the explosion of an iron core of an 11.2
$M_{\odot}$ star is simulated by two-dimensional neutrino-radiation
hydrodynamic code. The explosion is driven by the neutrino heating aided by
multi-dimensional hydrodynamic effects such as the convection. Following the
explosion phase, we continue the simulation focusing on the thermal evolution
of the protoneutron star up to $\sim$70 s when the crust of the neutron star is
formed using one-dimensional simulation. We find that the crust forms at
high-density region ($\rho\sim10^{14}$ g cm$^{-3}$) and it would proceed from
inside to outside. This is the first self-consistent simulation that
successfully follows from the collapse phase to the protoneutron star cooling
phase based on the multi-dimensional hydrodynamic simulation.


title:
Determinants of $(-1,1)$-matrices of the skew-symmetric type: a cocyclic
  approach

abstract:
  An $n$ by $n$ skew-symmetric type $(-1,1)$-matrix $K=[k_{i,j}]$ has $1$'s on
the main diagonal and $\pm 1$'s elsewhere with $k_{i,j}=-k_{j,i}$. The largest
possible determinant of such a matrix $K$ is an interesting problem. The
literature is extensive for $n\equiv 0 \mod 4$ (skew-Hadamard matrices), but
for $n\equiv 2\mod 4$ there are few results known for this question. In this
paper we approach this problem constructing cocyclic matrices over the dihedral
group of $2t$ elements, for $t$ odd, which are equivalent to $(-1,1)$-matrices
of skew type. Some explicit calculations have been done up to $t=11$. To our
knowledge, the upper bounds on the maximal determinant in orders 18 and 22 have
been improved.


title:
Spatially-Adaptive Reconstruction in Computed Tomography using Neural
  Networks

abstract:
  We propose a supervised machine learning approach for boosting existing
signal and image recovery methods and demonstrate its efficacy on example of
image reconstruction in computed tomography. Our technique is based on a local
nonlinear fusion of several image estimates, all obtained by applying a chosen
reconstruction algorithm with different values of its control parameters.
Usually such output images have different bias/variance trade-off. The fusion
of the images is performed by feed-forward neural network trained on a set of
known examples. Numerical experiments show an improvement in reconstruction
quality relatively to existing direct and iterative reconstruction methods.


title:
Mackey's theory of $\tau$-conjugate representations for finite groups.
  APPENDIX: On Some Gelfand Pairs and Commutative Association Schemes

abstract:
  The aim of the present paper is to expose two contributions of Mackey,
together with a more recent result of Kawanaka and Matsuyama, generalized by
Bump and Ginzburg, on the representation theory of a finite group equipped with
an involutory anti-automorphism (e.g. the anti-automorphism $g\mapsto g^{-1}$).
Mackey's first contribution is a detailed version of the so-called Gelfand
criterion for weakly symmetric Gelfand pairs. Mackey's second contribution is a
characterization of simply reducible groups (a notion introduced by Wigner).
The other result is a twisted version of the Frobenius-Schur theorem, where
"twisted" refers to the above-mentioned involutory anti-automorphism. APPENDIX:
We consider a special condition related to Gelfand pairs. Namely, we call a
finite group $G$ and its automorphism $\sigma$ satisfy Condition ($\bigstar$)
if the following condition is satisfied: if for $x,y\in G$, $x\cdot
x^{-\sigma}$ and $y\cdot y^{-\sigma}$ are conjugate in $G$, then they are
conjugate in $K=C_G(\sigma)$. We study the meanings of this condition, as well
as showing many examples of $G$ and $\sigma$ which do (or do not) satisfy
Condition ($\bigstar$).


title:
Electron correlation and impurity-induced quasiparticle resonance states
  in cuprate superconductors

abstract:
  We theoretically study the quasiparticle resonance states around a
nonmagnetic impurity in cuprate superconductors based on t-t'-J-U model. The
purpose of introducing the Coulomb repulsive interaction U is to partially
impose the double occupancy constraint by employing the Gutzwiller projected
mean-field approximation. We determine the spatial variation of the order
parameter and the local density of states (LDOS) by self-consistently solving
Bogoliubov-de Gennes equations. We find that in the large U limit, a
zero-energy resonance peak in the LDOS indeed appears for the impurity
potential in the unitary limit, at the same time the asymmetric superconducting
coherence peaks are strongly suppressed. As U decreases the electron double
occupancy d is permitted and gradually increases, leading to the decreasing of
order parameter. In particular the above zero-energy resonance peak begins to
evolve into a double-peaked structure since a critical value $d_{c}$. These
important feathers are qualitatively agreement with the scanning tunneling
spectroscopy experiments, and uncover the essential role played by the electron
correlation in cuprate superconductors.


title:
The spreading front of invasive species in favorable habitat or
  unfavorable habitat

abstract:
  Spatial heterogeneity and habitat characteristic are shown to determine the
asymptotic profile of the solution to a reaction-diffusion model with free
boundary, which describes the moving front of the invasive species. A threshold
value $R_0^{Fr}(D,t)$ is introduced to determine the spreading and vanishing of
the invasive species. We prove that if $R_0^{Fr}(D,t_0)\geq 1$ for some
$t_0\geq 0$, the spreading must happen; while if $R_0^{Fr}(D,0)<1$, the
spreading is also possible. Our results show that the species in the favorable
habitat can establish itself if the diffusion is slow or the occupying habitat
is large. In an unfavorable habitat, the species dies out if the initial value
of the species is small. However, big initial number of the species is benefit
for the species to survive. When the species spreads in the whole habitat, the
asymptotic spreading speed is given. Some implications of these theoretical
results are also discussed.


title: Liouvillian integrability of polynomial differential systems

abstract:
  M.F. Singer [Liouvillian first integrals of differential equations, Trans.
Amer. Math. Soc. 333 (1992), 673--688] proved the equivalence between
Liouvillian integrability and Darboux integrability for two dimensional
polynomial differential systems. In this paper we will extend Singer's result
to any finite dimensional polynomial differential systems. We prove that if an
n--dimensional polynomial differential system has n-1 functionally independent
Darboux Jacobian multiplier then it has n-1 functionally independent
Liouvillian first integrals. Conversely if the system is Liouvillian integrable
then it has a Darboux Jacobian multiplier.


title: The ins and outs of iteration in Mezzo

abstract:
  This is a talk proposal for HOPE 2013. Using iteration over a collection as a
case study, we wish to illustrate the strengths and weaknesses of the prototype
programming language Mezzo.


title: Spatio-temporal exceedance locations and confidence regions

abstract:
  An exceedance region is the set of locations in a spatial domain where a
process exceeds some threshold. Examples of exceedance regions include areas
where ozone concentrations exceed safety standards, there is high risk for
tornadoes or floods, or heavy-metal levels are dangerously high. Identifying
these regions in a spatial or spatio-temporal setting is an important
responsibility in environmental monitoring. Exceedance regions are often
estimated by finding the areas where predictions from a statistical model
exceed some threshold. Even when estimation error is quantifiable at individual
locations, the overall estimation error of the estimated exceedance region is
still unknown. A method is presented for constructing a confidence region
containing the true exceedance region of a spatio-temporal process at a certain
time. The underlying latent process and any measurement error are assumed to be
Gaussian. Conventional techniques are used to model the spatio-temporal data,
and then conditional simulation is combined with hypothesis testing to create
the desired confidence region. A simulation study is used to validate the
approach for several levels of spatial and temporal dependence. The methodology
is used to identify regions of Oregon having high precipitation levels and also
used in comparing climate models and assessing climate change using climate
models from the North American Regional Climate Change Assessment Program.


title: Studying Quantum Field Theory

abstract:
  The paper puts together some loosely connected observations, old and new, on
the concept of a quantum field and on the properties of Feynman amplitudes. We
recall, in particular, the role of (exceptional) elementary induced
representations of the quantum mechanical conformal group SU(2,2) in the study
of gauge fields and their higher spin generalization. A recent revival of the
(Bogolubov-)Epstein-Glaser approach to position space renormalization is
reviewed including an application to the calculation of residues of primitively
divergent graphs. We end up with an optimistic outlook of current developments
of analytic methods in perturbative QFT which combine the efforts of
theoretical physicists, algebraic geometers and number theorists.


title:
A Fraud Detection Visualization System Utilizing Radial Drawings and
  Heat-maps

abstract:
  We present a prototype system developed in cooperation with a business
organization that combines information visualization and pattern-matching
techniques to detect fraudulent activity by employees. The system is built upon
common fraud patterns searched while trying to detect occupational fraud
suggested by internal auditors of a business company. The main visualization of
the system consists of a multi-layer radial drawing that represents the
activity of the employees and clients. Each layer represents a different
examined pattern whereas heat-maps indicating suspicious activity are
incorporated in the visualization. The data are first preprocessed based on a
decision tree generated by the examined patterns and each employee is assigned
a value indicating whether or not there exist indications of fraud. The
visualization is presented as an animation and the employees are visualized one
by one according to their severity values together with their related clients.


title:
Displaced vertices and long-lived charged particles in the NMSSM with
  right-handed sneutrinos

abstract:
  We study LHC signatures of displaced vertices and long-lived charged
particles within the context of the Next-to-Minimal Supersymmetric Standard
Model with right-handed (RH) sneutrinos. In this construction the RH neutrino
can be produced directly from Higgs decays or in association with a RH
sneutrino when the latter is the lightest supersymmetric particle. The RH
neutrino is generally long-lived, since its decay width is proportional to the
neutrino Yukawa, a parameter which is predicted to be small. The RH neutrino
late decay can therefore give rise to displaced vertices at the LHC, which can
be identified through the decay products, which involve two leptons (2l+ MET)
or a lepton with two jets (ljj). We simulate this signal for the current LHC
configuration (a centre of mass of 8 TeV and an integrated luminosity of L=20
fb^-1), and a future one (13 TeV and L=100 fb^-1). We show that a region of the
parameter space of this model can be probed and that the RH neutrino mass can
be reconstructed from the end-point of the two-lepton invariant mass
distribution or the central value of the mass distribution for two jets plus
one lepton. Another exotic signature of this construction is the production of
a long-lived stau. If the stau is the next-to-lightest supersymmetric particle,
it can decay through diagrams involving the small neutrino Yukawa, and would
escape the detector leaving a characteristic trail. We also simulate this
signal for various benchmark points and show that the model can be within the
reach of the future run of the LHC.


title: Assessment of mortgage default risk via Bayesian state space models

abstract:
  Managing risk at the aggregate level is crucial for banks and financial
institutions as required by the Basel III framework. In this paper, we
introduce discrete time Bayesian state space models with Poisson measurements
to model aggregate mortgage default rate. We discuss parameter updating,
filtering, smoothing, forecasting and estimation using Markov chain Monte Carlo
methods. In addition, we investigate the dynamic behavior of the default rate
and the effects of macroeconomic variables. We illustrate the use of the
proposed models using actual U.S. residential mortgage data and discuss
insights gained from Bayesian analysis.


title:
On the number of non-comparable pairs of elements in a distributive
  lattice

abstract:
  In this article we introduce the study of the number of pairs of
non-comparable elements in a distributive lattice $\L$. We give several tight
lower and upper bounds for the number and give as an application the lattices
precisely for which the algebraic variety associated to is a complete
intersection.