title: On the B-discrete spectrum

abstract:
  In this paper, we introduce the B-discrete spectrum of an unbounded closed
operator and we prove that a closed operator has a purely B-discrete spectrum
if and only if it has a meromorphic resolvent. After that, we study the
stability of the B-discrete spectrum under several type of perturbations and we
establish that two closed invertible linear operators having quasisimilar
totally paranormal inverses have equal spectra and B-discrete spectra.


title: SenseFlow: An Experimental Study for Tracking People

abstract:
  The main challenges in large-scale people tracking are the recognition of
people density in a specific area and tracking the people flow path. To address
these challenges, we present SenseFlow, a lightweight people tracking system.
SenseFlow utilises off-the-shelf devices which sniff probe requests
periodically polled by user's smartphones in a passive manner. We demonstrate
the feasibility of SenseFlow by building a proof-of-concept prototype and
undertaking extensive evaluations in real-world settings. We deploy the system
in one laboratory to study office hours of researchers, a crowded public area
in city to evaluate the scalability and performance "in the wild", and four
classrooms in the university to monitor the number of students. We also
evaluate SenseFlow with varying walking speeds and different models of
smartphones to investigate the people flow tracking performance.


title: Groupes de Galois motivques et p\'eriodes

abstract:
  In the mid sixties, A. Grothendieck envisioned a vast generalization of
Galois theory to systems of polynomials in several variables, motivic Galois
theory, and introduced tannakian categories on this occasion. In characteristic
zero, various unconditional approaches were later proposed. The most precise
one, due to J. Ayoub, relies on Voevodsky theory of mixed motives and on a new
tannakian theory. It sheds new light on periods of algebraic varieties, and
shows in particular that polynomial relations between periods of a pencil of
algebraic varieties always arise from Stokes formula.


title:
On the regularity of solutions to the $k$-generalized Korteweg-de Vries
  equation

abstract:
  This work is concerned with special regularity properties of solutions to the
$k$-generalized Korteweg-de Vries equation. In \cite{IsazaLinaresPonce} it was
established that if the initial datun $u_0\in H^l((b,\infty))$ for some
$l\in\mathbb Z^+$ and $b\in \mathbb R$, then the corresponding solution
$u(\cdot,t)$ belongs to $H^l((\beta,\infty))$ for any $\beta \in \mathbb R$ and
any $t\in (0,T)$. Our goal here is to extend this result to the case where
$\,l\in \mathbb R^+$.


title:
Analytical theory for highly elliptical orbits including time-dependent
  perturbations

abstract:
  Traditional analytical theories of celestial mechanics are not well-adapted
when dealing with highly elliptical orbits. On the one hand, analytical
solutions are quite generally expanded into power series of the eccentricity
and so limited to quasi-circular orbits. On the other hand, the time-dependency
due to the motion of the third body (e.g. Moon and Sun) is almost always
neglected. We propose several tools to overcome these limitations. Firstly, we
have expanded the third-body disturbing function into a finite polynomial using
Fourier series in multiple of the satellite's eccentric anomaly (instead of the
mean anomaly) and involving Hansen-like coefficients. Next, by combining the
classical Brouwer-von Zeipel procedure and the time-dependent Lie-Deprit
transforms, we have performed a normalization of the expanded Hamiltonian in
order to eliminate all the periodic terms. One of the benefits is that the
original Brouwer solution for J2 is not modified. The main difficulty lies in
the fact that the generating functions of the transformation must be computed
by solving a partial differential equation, involving derivatives with respect
to the mean anomaly, which appears implicitly in the perturbation. We present a
method to solve this equation by means of an iterative process. Finally we have
obtained an analytical tool useful for the mission analysis, allowing to
propagate the osculating motion of objects on highly elliptical orbits (e>0.6)
over long periods efficiently with very high accuracy, or to determine initial
elements or mean elements. Comparisons between the complete solution and the
numerical simulations will be presented.

categories: astro-ph.EP math-ph math.MP physics.space-ph


title: Automated Space/Time Scaling of Streaming Task Graph

abstract:
  In this paper, we describe a high-level synthesis (HLS) tool that
automatically allows area/throughput trade-offs for implementing streaming task
graphs (STG). Our tool targets a massively parallel processor array (MPPA)
architecture, very similar to the Ambric MPPA chip architecture, which is to be
implemented as an FPGA overlay. Similar to Ambric tools, our HLS tool accepts a
STG as input written in a subset of Java and a structural language in the style
of a Kahn Processing Network (KPN). Unlike the Ambric tools, our HLS tool
analyzes the parallelism internal to each Java "node" and evaluates the
throughput and area of several possible implementations. It then analyzes the
full graph for bottlenecks or excess compute capacity, selects an
implementation for each node, and even considers replicating or splitting nodes
while either minimizing area (for a fixed throughput target), or maximizing
throughput (for a fixed area target). In addition to traditional node selection
and replication methods used in prior work, we have uniquely implemented node
combining and splitting to find a better area/throughput trade-off. We present
two optimization approaches, a formal ILP formulation and a heuristic solution.
Results show that the heuristic is more flexible and can find design points not
available to the ILP, thereby achieving superior results.


title:
The Widom-Rowlinson model, the hard-core model and the extremality of
  the complete graph

abstract:
  Let $H_{\mathrm{WR}}$ be the path on $3$ vertices with a loop at each vertex.
D. Galvin conjectured, and E. Cohen, W. Perkins and P. Tetali proved that for
any $d$-regular simple graph $G$ on $n$ vertices we have
$$\hom(G,H_{\mathrm{WR}})\leq \hom(K_{d+1},H_{\mathrm{WR}})^{n/(d+1)}.$$ In
this paper we give a short proof of this theorem together with the proof of a
conjecture of Cohen, Perkins and Tetali. Our main tool is a simple bijection
between the Widom-Rowlinson model and the hard-core model on another graph. We
also give a large class of graphs $H$ for which we have $$\hom(G,H)\leq
\hom(K_{d+1},H)^{n/(d+1)}.$$ In particular, we show that the above inequality
holds if $H$ is a path or a cycle of even length at least $6$ with loops at
every vertex.


title: A Proposal for Semantic Map Representation and Evaluation

abstract:
  Semantic mapping is the incremental process of "mapping" relevant information
of the world (i.e., spatial information, temporal events, agents and actions)
to a formal description supported by a reasoning engine. Current research
focuses on learning the semantic of environments based on their spatial
location, geometry and appearance. Many methods to tackle this problem have
been proposed, but the lack of a uniform representation, as well as standard
benchmarking suites, prevents their direct comparison. In this paper, we
propose a standardization in the representation of semantic maps, by defining
an easily extensible formalism to be used on top of metric maps of the
environments. Based on this, we describe the procedure to build a dataset
(based on real sensor data) for benchmarking semantic mapping techniques, also
hypothesizing some possible evaluation metrics. Nevertheless, by providing a
tool for the construction of a semantic map ground truth, we aim at the
contribution of the scientific community in acquiring data for populating the
dataset.


title: On cubic Hodge integrals and random matrices

abstract:
  A conjectural relationship between the GUE partition function with even
couplings and certain special cubic Hodge integrals over the moduli spaces of
stable algebraic curves is under consideration.


title:
Mobile impurity in a Fermi sea from the functional renormalization group
  analytically continued to real time

abstract:
  Motivated by experiments with cold atoms, we investigate a mobile impurity
immersed in a Fermi sea in three dimensions at zero temperature by means of the
functional renormalization group. We first perform the derivative expansion of
the effective action to calculate the ground state energy and Tan's contact
across the polaron-molecule transition for several mass imbalances. Next we
study quasiparticle properties of the impurity by using a real-time method
recently developed in nuclear physics, which allows one to go beyond the
derivative expansion. We obtain the spectral function of the polaron, the
effective mass and quasiparticle weight of attractive and repulsive polarons,
and clarify how they are affected by mass imbalances.


title:
Towards a complete characterization of the effective elasticity tensors
  of mixtures of an elastic phase and an almost rigid phase

abstract:
  The set $GU_f$ of possible effective elastic tensors of composites built from
two materials with positive definite elasticity tensors $\BC_1$ and
$\BC_2=\Gd\BC_0$ comprising the set $U=\{\BC_1,\Gd\BC_0\}$ and mixed in
proportions $f$ and $1-f$ is partly characterized in the limit $\Gd\to\infty$.
The material with tensor $\BC_2$ corresponds to a material which (for technical
reasons) is almost rigid in the limit $\Gd\to \infty$. The paper, and the
underlying microgeometries, have many aspects in common with the companion
paper "On the possible effective elasticity tensors of 2-dimensional printed
materials". The chief difference is that one has a different algebraic problem
to solve: determining the subspaces of stress fields for which the thin walled
structures can be rigid, rather than determining, as in the companion paper,
the subspaces of strain fields for which the thin walled structure is
compliant. Recalling that $GU_f$ is completely characterized through minimums
of sums of energies, involving a set of applied strains, and complementary
energies, involving a set of applied stresses, we provide descriptions of
microgeometries that in appropriate limits achieve the minimums in many cases.
In these cases the calculation of the minimum is reduced to a finite
dimensional minimization problem that can be done numerically. Each
microgeometry consists of a union of walls in appropriate directions, where the
material in the wall is an appropriate $p$-mode material, that is almost rigid
to $6-p\leq 5$ independent applied stresses, yet is compliant to any strain in
the orthogonal space. Thus the walls, by themselves, can support stress with
almost no deformation. The region outside the walls contains "Avellaneda
material" that is a hierarchical laminate which minimizes an appropriate sum of
elastic energies.


title: Resource Destroying Maps

abstract:
  Resource theory is a widely-applicable framework for analyzing the physical
resources required for given tasks, such as computation, communication, and
energy extraction. In this paper, we propose a general scheme for analyzing
resource theories based on resource destroying maps, which leave resource-free
states unchanged but erase the resource stored in all other states. We
introduce a group of general conditions that determine whether a quantum
operation exhibits typical resource-free properties in relation to a given
resource destroying map. Our theory reveals fundamental connections among basic
elements of resource theories, in particular, free states, free operations, and
resource measures. In particular, we define a class of simple resource measures
that can be calculated without optimization, and that are monotone
nonincreasing under operations that commute with the resource destroying map.
We apply our theory to the resources of coherence and quantum correlations
(e.g., discord), two prominent features of nonclassicality.


title: Large magnetoresistance in the antiferromagnetic semi-metal NdSb

abstract:
  There has been considerable interest in topological semi-metals that exhibit
extreme magnetoresistance (XMR). These have included materials lacking
inversion symmetry such as TaAs, as well Dirac semi-metals such as Cd3As2.
However, it was reported recently that LaSb and LaBi also exhibit XMR, even
though the rock-salt structure of these materials has inversion symmetry, and
the band-structure calculations do not show a Dirac dispersion in the bulk.
Here, we present magnetoresistance and specific heat measurements on NdSb,
which is isostructural with LaSb. NdSb has an antiferromagnetic groundstate,
and in analogy with the lanthanum monopnictides, is expected to be a
topologically non-trivial semi-metal. We show that NdSb has an XMR of 10^4 %,
even within the AFM state, illustrating that XMR can occur independently of the
absence of time reversal symmetry breaking in zero magnetic field. The
persistence of XMR in a magnetic system offers promise of new functionality
when combining topological matter with electronic correlations. We also find
that in an applied magnetic field below the Neel temperature there is a first
order transition, consistent with evidence from previous neutron scattering
work.


title: Exclusive $\omega$ meson muoproduction on transversely polarised protons

abstract:
  Exclusive production of $\omega$ mesons was studied at the COMPASS experiment
by scattering $160~\mathrm{GeV}/\mathit{c}$ muons off transversely polarised
protons. Five single-spin and three double-spin azimuthal asymmetries were
measured in the range of photon virtuality $1~(\mathrm{GeV}/\mathit{c})^2 < Q^2
< 10~(\mathrm{GeV}/\mathit{c})^2$, Bjorken scaling variable $0.003 <
x_{\mathit{Bj}} < 0.3$ and transverse momentum squared of the $\omega$ meson
$0.05~(\mathrm{GeV}/\mathit{c})^2 < p_{T}^{2} <
0.5~(\mathrm{GeV}/\mathit{c})^2$. The measured asymmetries are sensitive to the
nucleon helicity-flip Generalised Parton Distributions (GPD) $E$ that are
related to the orbital angular momentum of quarks, the chiral-odd GPDs $H_{T}$
that are related to the transversity Parton Distribution Functions, and the
sign of the $\pi\omega$ transition form factor. The results are compared to
recent calculations of a GPD-based model.


title: Arithmetical structures on graphs with connectivity one

abstract:
  Given a graph $G$, an arithmetical structure on $G$ is a pair of positive
integer vectors $({\bf d},{\bf r})$ such that $\mathrm{gcd}({\bf r}_v\, |
\,v\in V(G))=1$ and \[ (\mathrm{diag}({\bf d})-A){\bf r}=0, \] where $A$ is the
adjacency matrix of $G$. We describe the arithmetical structures on graph $G$
with a cut vertex $v$ in terms of the arithmetical structures on their blocks.
More precisely, if $G_1,\ldots,G_s$ are the induced subgraphs of $G$ obtained
from each of the connected components of $G-v$ by adding the vertex $v$ and
their incident edges, then the arithmetical structures on $G$ are in one to one
correspondence with the $v$-rational arithmetical structures on the $G_i$'s. We
introduce the concept of rational arithmetical structure, which corresponds to
an arithmetical structure where some of the integrality conditions are relaxed.


title:
A novel analog power supply for gain control of the Multi-Pixel Photon
  Counter (MPPC)

abstract:
  Silicon Photo-Multipliers (SiPM) are regarded as novel photo-detectors to
replace conventional Photo-Multiplier Tubes (PMTs). However, the breakdown
voltage dependence on the ambient temperature results in a gain variation of
$\sim$3$\% /^{\circ} \mathrm C$. This severely limits the application of this
device in experiments with wide range of operating temperature, especially in
space missions. An experimental setup was established to investigate the
temperature and bias voltage dependence of gain for the Multi-Pixel Photon
Counter (MPPC). The gain and breakdown voltage dependence on operating
temperature of an MPPC can be approximated by a linear function, which is
similar to the behavior of a zener diode. The measured temperature coefficient
of the breakdown voltage is $(59.4 \pm 0.4$ mV)$/^{\circ} \mathrm C$. According
to this fact, an analog power supply based on two zener diodes and an
operational amplifier was designed with a positive temperature coefficient. The
measured temperature dependence for the designed power supply is between 63.65
to 64.61~mV/$^{\circ} \mathrm C$ at different output voltages. The designed
power supply can bias the MPPC at an over-voltage with a temperature variation
of $\sim$ 5~mV$/^{\circ} \mathrm C$. The gain variation of the MPPC biased at
over-voltage of 2~V was reduced from 2.8$\% /^{\circ} \mathrm C$ to 0.3$\%
/^{\circ} \mathrm C$ when biased the MPPC with the designed power supply for
gain control. Detailed design and performance of the analog power supply in the
temperature range from -42.7$^{\circ}\mathrm{C}$ to 20.9$^{\circ}\mathrm{C}$
will be discussed in this paper.


title: Landstad-Vaes theory for locally compact quantum groups

abstract:
  Landstad-Vaes theory deals with the structure of the crossed product of a
C$^*$-algebra by an action of locally compact (quantum) group. In particular it
describes the position of original algebra inside crossed product. The problem
was solved in 1979 by Landstad for locally compact groups and in 2005 by Vaes
for regular locally compact quantum groups. To extend the result to non-regular
groups we modify the notion of $G$-dynamical system introducing the concept of
weak action of quantum groups on C$^*$-algebras. It is still possible to define
crossed product (by weak action) and characterise the position of original
algebra inside the crossed product. The crossed product is unique up to an
isomorphism. At the end we discuss a few applications.


title:
Robust instrumental variable methods using multiple candidate
  instruments with application to Mendelian randomization

abstract:
  Mendelian randomization is the use of genetic variants to make causal
inferences from observational data. The field is currently undergoing a
revolution fuelled by increasing numbers of genetic variants demonstrated to be
associated with exposures in genome-wide association studies, and the public
availability of summarized data on genetic associations with exposures and
outcomes from large consortia. A Mendelian randomization analysis with many
genetic variants can be performed relatively simply using summarized data.
However, a causal interpretation is only assured if each genetic variant
satisfies the assumptions of an instrumental variable. To provide some
protection against failure of these assumptions, robust methods for
instrumental variable analysis have been proposed. Here, we develop three
extensions to instrumental variable methods using: i) robust regression, ii)
the penalization of weights from candidate instruments with heterogeneous
causal estimates, and iii) L1 penalization. Results from a wide variety of
robust methods, including the recently-proposed MR-Egger and median-based
methods, are compared in an extensive simulation study. We demonstrate that two
methods, robust regression in an inverse-variance weighted method and a simple
median of the causal estimates from the individual variants, have considerably
improved Type 1 error rates compared with conventional methods in a wide
variety of scenarios when up to 30% of the genetic variants are invalid
instruments. While the MR-Egger method gives unbiased estimates when its
assumptions are satisfied, these estimates are less efficient than those from
other methods and are highly sensitive to violations of the assumptions.
Methods that make different assumptions should be used routinely to assess the
robustness of findings from applied Mendelian randomization investigations with
multiple genetic variants.


title:
Refined properties for the Mellin transform, with applications to
  convergence of families obtained by biasing or by the stationary excess
  operator

abstract:
  We first provide some properties of the Mellin transform of nonnegative
random variables, such that monotonicity, injectivity and effect of size
biasing. Convergence of Mellin transforms is also entirely formalized through
convergence in distribution and uniform integrability. As an application, we
study a problem raised by Harkness and Shantaram (1969) who obtained, under
sufficient conditions, a limit theorem for sequences of nonnegative random
variables build with the iterated stationary excess operator. We reformulate
this problem through the concept of multiply monotone functions and through the
convergence of families build by the continuous time version of the iterated
stationary excess operator and also by size biasing. The latter allows us to
show that in our context, continuous time convergence is equivalent to discrete
time convergence, that the conditions of Harkness and Shantaram are actually
necessary and that the only possible limits in distribution are mixture of
exponential with lognormal distributions.


title:
A constrained clustering based approach for matching a collection of
  feature sets

abstract:
  In this paper, we consider the problem of finding the feature correspondences
among a collection of feature sets, by using their point-wise unary features.
This is a fundamental problem in computer vision and pattern recognition, which
also closely relates to other areas such as operational research. Different
from two-set matching which can be transformed to a quadratic assignment
programming task that is known NP-hard, inclusion of merely unary attributes
leads to a linear assignment problem for matching two feature sets. This
problem has been well studied and there are effective polynomial global optimum
solvers such as the Hungarian method. However, it becomes ill-posed when the
unary attributes are (heavily) corrupted. The global optimal correspondence
concerning the best score defined by the attribute affinity/cost between the
two sets can be distinct to the ground truth correspondence since the score
function is biased by noises. To combat this issue, we devise a method for
matching a collection of feature sets by synergetically exploring the
information across the sets. In general, our method can be perceived from a
(constrained) clustering perspective: in each iteration, it assigns the
features of one set to the clusters formed by the rest of feature sets, and
updates the cluster centers in turn. Results on both synthetic data and real
images suggest the efficacy of our method against state-of-the-arts.


title:
Connecting Electroweak Symmetry Breaking and Flavor: A Light Dilaton
  ${\cal D}$ and a Sequential Heavy Quark Doublet $Q$

abstract:
  The 125 GeV boson is quite consistent with the Higgs boson of the Standard
Model (SM), but there is a challenge from Anderson whether this particle is in
the Lagrangian. As LHC Run 2 takes its final year of running, we ought to
reflect and make sure we have gotten everything right. The ATLAS and CMS
combined Run 1 analysis claims 5.4$\sigma$ measurement of vector boson fusion
(VBF) production that is consistent with SM, which seemingly refutes Anderson.
However, to verify the source of electroweak symmetry breaking (EWSB), we
caution that VBF measurement is too important for us to be imprudent in any
way, and gluon-gluon fusion (ggF) with similar tag jets must be simultaneously
\emph{measured}, which should be achievable at LHC Run 2. The point is to truly
test the dilaton possibility, the pseudo-Goldstone boson of scale invariance
violation. We illustrate EWSB by dynamical mass generation of a sequential
quark doublet $Q$ via its ultrastrong Yukawa coupling, and argue how this might
be consistent with a 125 GeV dilaton, ${\cal D}$. The ultraheavy $2m_Q \gtrsim
4$--5 TeV scale explains the absence of New Physics so far, while the mass
generation mechanism shields us from the UV theory for the strong Yukawa
coupling. Collider and flavor physics implications are briefly touched upon.
Current Run 2 analyses show correlations between the ggF and VBF measurements,
but the newly observed $t\bar tH$ production at LHC poses a challenge.


title: On the $a$-points of the derivatives of the Riemann zeta function

abstract:
  We prove three results on the $a$-points of the derivatives of the Riemann
zeta function. The first result is a formula of the Riemann-von Mangoldt type;
we estimate the number of the $a$-points of the derivatives of the Riemann zeta
function. The second result is on certain exponential sum involving $a$-points.
The third result is an analogue of the zero density theorem. We count the
$a$-points of the derivatives of the Riemann zeta function in $1/2-(\log\log
T)^2/\log T<\Re s<1/2+(\log\log T)^2/\log T$.


title: A Radial Velocity Study of the Intermediate Polar EX Hydrae

abstract:
  A study on the intermediate polar EX Hya is presented, based on simultaneous
photometry and high dispersion spectroscopic observations, during four
consecutive nights. The strong photometric modulation related to with the
67-min spin period of the primary star is clearly present, as well as the
narrow eclipses associated to the orbital modulation. Since our eclipse timings
have been obtained almost 91,000 cycles since the last reported observations,
we present new linear ephemeris, although we cannot rule out a sinusoidal
variation suggested by previous authors. The system mainly shows double-peaked
H$\alpha$, H$\beta$ and HeI $\lambda$5876 \AA emission lines. From the profile
of the H$\alpha$ line, we find two components; one with a steep rise and
velocities not larger than $\sim$1000 km s$^{-1}$ and another broader component
extending up to $\sim$2000 km s$^{-1}$, which we interpret as coming mainly
from the inner disc. A strong and variable hotspot is found and a stream-like
structure is seen at times. We show that the best solution correspond to $K_1 =
58 \pm 5$ km s$^{-1}$ from H$\alpha$, from the two emission components, which
are both in phase with the orbital modulation. We remark on a peculiar effect
in the radial velocity curve around phase zero, which could be interpreted as a
Rositter-MacLaughlin-like effect, which has been taken into account before
deriving $K_1$. This value is compatible with the values found in
high-resolution both in the ultraviolet and X-ray. We find: $M_{1} = 0.78 \pm
0.03$ M$_{\odot}$, $ M_{2} = 0.10 \pm 0.02$ M$_{\odot}$ and $a = 0.67 \pm 0.01$
R$_{\odot}$. Doppler Tomography has been applied, to construct six Doppler
tomograms for single orbital cycles spanning the four days of observations to
support our conclusions. Our results indicate that EX Hya has a well formed
disc and that the magnetosphere should extend only to about
$3.75\,R_{\rm{WD}}$.


title: The 4 Pi Sky Transient Alerts Hub

abstract:
  We introduce the 4 Pi Sky 'hub', a collection of open data-services and
underlying software packages built for rapid, fully automated reporting and
response to astronomical transient alerts. These packages build on the mature
'VOEvent' standardized message-format, and aim to provide a decentralized and
open infrastructure for handling transient alerts. In particular we draw
attention to the initial release of voeventdb, an archive and remote-query
service that allows astronomers to make historical queries about transient
alerts. By employing spatial filters and web-of-citation lookups, voeventdb
enables cross-matching of transient alerts to bring together data from multiple
sources, as well as providing a point of reference when planning new follow-up
campaigns. We also highlight the recent addition of optical-transient feeds
from the ASASSN and GAIA projects to our VOEvent distribution stream. Both the
source-code and deployment-scripts which implement these services are freely
available and permissively licensed, with the intention that other teams may
use them to implement local or project-specific VOEvent archives. In the course
of describing these packages we provide a basic primer for getting started with
automated transient astronomy, including a condensed introduction to the
VOEvent standard.


title:
Enhancement of Low-cost GNSS Localization in Connected Vehicle Networks
  Using Rao-Blackwellized Particle Filters

abstract:
  An essential function for automated vehicle technologies is accurate
localization. It is difficult, however, to achieve lane-level accuracy with
low-cost Global Navigation Satellite System (GNSS) receivers due to the biased
noisy pseudo-range measurements. Approaches such as Differential GNSS can
improve the accuracy, but usually require an enormous amount of investment in
base stations. The emerging connected vehicle technologies provide an
alternative approach to improving the localization accuracy. It has been shown
in this paper that localization accuracy can be enhanced by fusing GNSS
information within a group of connected vehicles and matching the configuration
of the group to a digital map to eliminate the common bias in localization. A
Rao-Blackwellized particle filter (RBPF) was used to jointly estimate the
common biases of the pseudo-ranges and the vehicles positions. Multipath
biases, which are non-common to vehicles, were mitigated by a multi-hypothesis
detection-rejection approach. The temporal correlation was exploited through
the prediction-update process. The proposed approach was compared to the
existing static and smoothed static methods in the intersection scenario.
Simulation results show that the proposed algorithm reduced the estimation
error by fifty percent and reduced the estimation variance by two orders of
magnitude.


title:
Detec\c{c}\~ao de comunidades em redes complexas para identificar
  gargalos e desperd\'icio de recursos em sistemas de \^onibus

abstract:
  We propose here a methodology to help to understand the shortcomings of
public transportation in a city via the mining of complex networks representing
the supply and demand of public transport. We show how to build these networks
based upon data on smart card use in buses via the application of algorithms
that estimate an OD and reconstruct the complete itinerary of the passengers.
The overlapping of the two networks sheds light in potential overload and waste
in the offer of resources that can be mitigated with strategies for balancing
supply and demand.


title: Sidney Coleman's Harvard

abstract:
  A talk presented at the April 2016 APS meeting in Salt Lake City: The speaker
had the great good fortune to take an undergraduate course in group theory from
Sidney Coleman, and (after graduate school away) was hired by Coleman to a
postdoctoral position and eventually became a faculty colleague. He will share
some still vivid memories of this remarkable character.


title: Electromagnetic signatures of the chiral anomaly in Weyl semimetals

abstract:
  Weyl semimetals are predicted to realize the three-dimensional axial anomaly
first discussed in particle physics. The anomaly leads to unusual transport
phenomena such as the chiral magnetic effect in which an applied magnetic field
induces a current parallel to the field. Here we investigate diagnostics of the
axial anomaly based on the fundamental equations of axion electrodynamics. We
find that materials with Weyl nodes of opposite chirality and finite energy
separation immersed in a uniform magnetic field exhibit an anomaly-induced
oscillatory magnetic field with a period set by the chemical potential
difference of the nodes. In the case where a chemical potential imbalance is
created by applying parallel electric and magnetic fields, we find a
suppression of the magnetic field component parallel to the electric field
inside the material for rectangular samples, suggesting that the chiral
magnetic current opposes this imbalance. For cylindrical geometries, we instead
find an enhancement of this magnetic field component along with an
anomaly-induced azimuthal component. We propose experiments to detect such
magnetic signatures of the axial anomaly.


title:
Non-equilibrium Fluctuational Quantum Electrodynamics: Heat Radiation,
  Heat Transfer, and Force

abstract:
  Quantum and thermal fluctuations of electromagnetic waves are the cornerstone
of quantum and statistical physics, and inherent to such phenomena as thermal
radiation and van der Waals forces. While the basic principles are the material
of elementary texts, recent experimental and technological advances have made
it necessary to come to terms with counterintuitive consequences of
electromagnetic fluctuations at short scales -- in the so called {\it
near-field} regime. We focus on three manifestations of such behavior: {\bf
(i)} The Stefan--Boltzmann law describes thermal radiation from macroscopic
bodies, but fails to account for magnitude, polarization and coherence of
radiation from small objects (say compared to the skin depth). {\bf (ii)} The
heat transfer between two bodies at similar close proximity is dominated by
evanescent waves, and can be several orders of magnitude larger than the
classical contribution due to propagating waves. {\bf (iii)} Casimir/van der
Waals interactions are a dominant force between objects at sub-micron
separation; the non-equilibrium analogs of this force (for objects at different
temperatures) have not been sufficiently explored (at least experimentally). To
explore these phenomena we introduce the tool of fluctuational quantum
electrodynamics (QED) originally introduced by Rytov in the 1950s. Combined
with a scattering formalism, this enables studies of heat radiation and
transfer, equilibrium and non-equilibrium forces for objects of different
material properties, shapes, separations and arrangements.


title:
A multiwavelength investigation of the HII region S311: Young stellar
  population and star formation

abstract:
  We present a multiwavelength investigation of the young stellar population
and star formation activities around the \hii region Sharpless 311. Using our
deep near-infrared observations and archival {\it Spitzer}-IRAC observations,
we have detected a total of 125 young stellar objects (YSOs) in an area of
$\sim$86 arcmin$^2$. The YSOs sample include 8 Class I and 117 Class II
candidate YSOs. The mass completeness of the identified YSOs sample is
estimated to be 1.0 \msun. The ages and masses of the majority of the candidate
YSOs are estimated to be in the range of $\sim$0.1$-$5 Myr and $\sim$0.3$-$6
\msun, respectively. The 8 \mum image of S311 displays an approximately
spherical cavity around the ionizing source which is possibly created due to
the expansion of the \hii region. The spatial distribution of the candidate
YSOs reveals that a significant number of them are distributed systematically
along the 8 $\mu$m emission with a majority clustered around the eastern border
of the \hii region. Four clumps/compact \hii regions are detected in the radio
continuum observations at 1280 MHz, which might have been formed during the
expansion of the \hii region. The estimated dynamical age of the region,
main-sequence lifetime of the ionizing source, the spatial distribution and
ages of the candidate YSOs indicate triggered star formation in the complex.


title: Application-Driven Near-Data Processing for Similarity Search

abstract:
  Similarity search is a key to a variety of applications including
content-based search for images and video, recommendation systems, data
deduplication, natural language processing, computer vision, databases,
computational biology, and computer graphics. At its core, similarity search
manifests as k-nearest neighbors (kNN), a computationally simple primitive
consisting of highly parallel distance calculations and a global top-k sort.
However, kNN is poorly supported by today's architectures because of its high
memory bandwidth requirements.
  This paper proposes an application-driven near-data processing accelerator
for similarity search: the Similarity Search Associative Memory (SSAM). By
instantiating compute units close to memory, SSAM benefits from the higher
memory bandwidth and density exposed by emerging memory technologies. We
evaluate the SSAM design down to layout on top of the Micron hybrid memory cube
(HMC), and show that SSAM can achieve up to two orders of magnitude
area-normalized throughput and energy efficiency improvement over multicore
CPUs; we also show SSAM is faster and more energy efficient than competing GPUs
and FPGAs. Finally, we show that SSAM is also useful for other data intensive
tasks like kNN index construction, and can be generalized to semantically
function as a high capacity content addressable memory.


title:
Electric potential and field calculation of charged BEM triangles and
  rectangles by Gaussian cubature

abstract:
  It is a widely held view that analytical integration is more accurate than
the numerical one. In some special cases, however, numerical integration can be
more advantageous than analytical integration. In our paper we show this
benefit for the case of electric potential and field computation of charged
triangles and rectangles applied in the boundary element method (BEM).
Analytical potential and field formulas are rather complicated (even in the
simplest case of constant charge densities), they have usually large
computation times, and at field points far from the elements they suffer from
large rounding errors. On the other hand, Gaussian cubature, which is an
efficient numerical integration method, yields simple and fast potential and
field formulas that are very accurate far from the elements. The simplicity of
the method is demonstrated by the physical picture: the triangles and
rectangles with their continuous charge distributions are replaced by discrete
point charges, whose simple potential and field formulas explain the higher
accuracy and speed of this method. We implemented the Gaussian cubature method
for the purpose of BEM computations both with CPU and GPU, and we compare its
performance with two different analytical integration methods. The ten
different Gaussian cubature formulas presented in our paper can be used for
arbitrary high-precision and fast integrations over triangles and rectangles.


title:
Generalized Volterra lattices: binary Darboux transformations and
  self-consistent sources

abstract:
  We study two families of (matrix versions of) generalized Volterra (or
Bogoyavlensky) lattice equations. For each family, the equations arise as
reductions of a partial differential-difference equation in one continuous and
two discrete variables, which is a realization of a general integrable equation
in bidifferential calculus. This allows to derive a binary Darboux
transformation and also self-consistent source extensions via general results
of bidifferential calculus. Exact solutions are constructed from the simplest
seed solutions.


title:
Characterization of sharp global Gaussian estimates for Schr\"odinger
  heat kernels

abstract:
  We investigate when the fundamental solution of the Schr\"odinger equation
$\partial_t=\Delta+V$ posseses sharp Gaussian bounds global in space and time.
We give a characterization for $V\leq 0$ and a sufficient condition for general
$V$.


title: Optimal Packings of 22 and 33 Unit Squares in a Square

abstract:
  Let $s(n)$ be the side length of the smallest square into which $n$
non-overlapping unit squares can be packed. In 2010, the author showed that
$s(13)=4$ and $s(46)=7$. Together with the result $s(6)=3$ by Keaney and Shiu,
these results strongly suggest that $s(m^2-3)=m$ for $m\ge 3$, in particular
for the values $m=5,6$, which correspond to cases that lie in between the
previous results.
  In this article we show that indeed $s(m^2-3)=m$ for $m=5,6$, implying that
the most efficient packings of 22 and 33 squares are the trivial ones. To
achieve our results, we modify the well-known method of sets of unavoidable
points by replacing them with continuously varying families of such sets.


title: Probing primordial features with future galaxy surveys

abstract:
  We study the capability of future measurements of the galaxy clustering power
spectrum to probe departures from a power-law spectrum for primordial
fluctuations. On considering the information from the galaxy clustering power
spectrum up to quasi-linear scales, i.e. $k<0.1$ h Mpc$^{-1}$, we present
forecasts for DESI, Euclid and SPHEREx in combination with CMB measurements. As
examples of departures in the primordial power spectrum from a simple
power-law, we consider four $Planck$ 2015 best-fits motivated by inflationary
models with different breaking of the slow-roll approximation. These four
representative models provide an improved fit to CMB temperature anisotropies,
although not at statistical significant level. As for other extensions in the
matter content of the simplest $\Lambda$CDM model, the complementarity of the
information in the resulting matter power spectrum expected from these galaxy
surveys and in the primordial power spectrum from CMB anisotropies can be
effective in constraining cosmological models. We find that the three galaxy
surveys can add significant information to CMB to better constrain the extra
parameters of the four models considered.


title: Correlated Disorder in van der Waals Heterostructures

abstract:
  The individual building blocks of van der Waals (vdW) heterostructures host
fascinating physical phenomena, ranging from ballistic electron transport in
graphene to striking optical properties of MoSe2 sheets. The presence of bonded
and non-bonded cohesive interactions in a vdW heterostructure, promotes
diversity in their structural arrangements, which in turn profoundly modulate
the properties of their individual constituents. Here, we report on the
presence of correlated structural disorder coexisting with the nearly perfect
crystallographic order along the growth direction of epitaxial vdW
heterostructures of Bi2Se3/graphene/SiC. Using the depth penetration of X-ray
diffraction microscopy and scattering, we probed their crystal structure from
atomic to mesoscopic length scales, to reveal that their structural diversity
is underpinned by spatially correlated disorder states. The presence of the
latter induces on a system, widely considered to behave as a collection of
nearly independent 2-dimensional units, a pseudo-3-dimensional character, when
subjected to epitaxial constraints and ordered substrate interactions. These
findings shed new light on the nature of the vast structural landscape of vdW
heterostructures and could enable new avenues in modulating their unique
properties by correlated disorder.


title:
Scalable Bayesian variable selection and model averaging under block
  orthogonal design

abstract:
  We propose a scalable algorithmic framework for exact Bayesian variable
selection and model averaging in linear models under the assumption that the
Gram matrix is block-diagonal, and as a heuristic for exploring the model space
for general designs. In block-diagonal designs our approach returns the most
probable model of any given size without resorting to numerical integration.
The algorithm also provides a novel and efficient solution to the frequentist
best subset selection problem for block-diagonal designs. Posterior
probabilities for any number of models are obtained by evaluating a single
one-dimensional integral that can be computed upfront, and other quantities of
interest such as variable inclusion probabilities and model averaged regression
estimates by carrying out an adaptive, deterministic one-dimensional numerical
integration. The overall computational cost scales linearly with the number of
blocks, which can be processed in parallel, and exponentially with the block
size, rendering it most adequate in situations where predictors are organized
in many moderately-sized blocks. For general designs, we approximate the Gram
matrix by a block-diagonal using spectral clustering and propose an iterative
algorithm that capitalizes on the block-diagonal algorithms to explore
efficiently the model space. All methods proposed in this article are
implemented in the R library mombf.


title:
Ultra broadband waveveguide coupler using an anisotropic sub-wavelength
  metamaterial

abstract:
  Multimode interference couplers are a fundamental building block in many
integrated photonic systems, ranging from high-speed coherent receivers to
quantum splitters. However, their basic structure has remained fundamentally
unchanged for almost four decades, limiting their size and operation bandwidth.
Using sub-wavelength metamaterials, photonic devices with break-through size
and performance have been recently reported. Leveraging the inherent anisotropy
of these structures, here we derive a semi-analytic expression that enables the
design of compact and ultra broadband multimode interference couplers. We
experimentally demonstrate virtually perfect operation over a bandwidth in
excess of 300nm (500nm in simulation), for a device three times shorter than
its conventional counterpart, making this the most broadband multimode
interference coupler reported to date. These results will enable ultra
broadband integrated systems for applications in communications and sensing.


title:
Distinguishing number and distinguishing index of neighbourhood corona
  of two graphs

abstract:
  The distinguishing number (index) $D(G)$ ($D'(G)$) of a graph $G$ is the
least integer $d$ such that $G$ has an vertex labeling (edge labeling) with $d$
labels that is preserved only by a trivial automorphism. The neighbourhood
corona of two graphs $G_1$ and $G_2$ is denoted by $G_1 \star G_2$ and is the
graph obtained by taking one copy of $G_1$ and $|V(G_1)|$ copies of $G_2$, and
joining the neighbours of the $i$th vertex of $G_1$ to every vertex in the
$i$th copy of $G_2$. In this paper we describe the automorphisms of the graph
$G_1\star G_2$. Using results on automorphisms, we study the distinguishing
number and the distinguishing index of $G_1\star G_2$. We obtain upper bounds
for $D(G_1\star G_2)$ and $D'(G_1\star G_2)$.


title:
Location Based Performance Model for Indoor mmWave Wearable
  Communication

abstract:
  Simultaneous use of high-end wearable wireless devices like smart glasses is
challenging in a dense indoor environment due to the high nature of
interference. In this scenario, the millimeter wave (mmWave) band offers
promising potential for achieving gigabits per second throughput. Here we
propose a novel system model for analyzing system performance of mmWave based
communication among wearables. The proposed model accounts for the non-isotropy
of the indoor environment and the effects of reflections that are predominant
for indoor mmWave signals. The effect of human body blockages are modeled and
the system performance is shown to hugely vary depending on the user location,
body orientation and the density of the network. Closed form expressions for
spatially averaged signal to interference plus noise ratio distribution are
also derived as a function of the location and orientation of a reference user.


title: Approximating the rectilinear crossing number

abstract:
  A straight-line drawing of a graph $G$ is a mapping which assigns to each
vertex a point in the plane and to each edge a straight-line segment connecting
the corresponding two points. The rectilinear crossing number of a graph $G$,
$\overline{cr}(G)$, is the minimum number of crossing edges in any
straight-line drawing of $G$. Determining or estimating $\overline{cr}(G)$
appears to be a difficult problem, and deciding if $\overline{cr}(G)\leq k$ is
known to be NP-hard. In fact, the asymptotic behavior of $\overline{cr}(K_n)$
is still unknown.
  In this paper, we present a deterministic $n^{2+o(1)}$-time algorithm that
finds a straight-line drawing of any $n$-vertex graph $G$ with
$\overline{cr}(G) + o(n^4)$ crossing edges. Together with the well-known
Crossing Lemma due to Ajtai et al. and Leighton, this result implies that for
any dense $n$-vertex graph $G$, one can efficiently find a straight-line
drawing of $G$ with $(1 + o(1))\overline{cr}(G)$ crossing edges.


title: Towards Self-Calibrating Inertial Body Motion Capture

abstract:
  This paper presents a novel online capable method for simultaneous estimation
of human motion in terms of segment orientations and positions along with
sensor-to-segment calibration parameters from inertial sensors attached to the
body. In order to solve this ill-posed estimation problem, state-of-the-art
motion, measurement and biomechanical models are combined with new stochastic
equations and priors. These are based on the kinematics of multi-body systems,
anatomical and body shape information, as well as, parameter properties for
regularisation. This leads to a constrained weighted least squares problem that
is solved in a sliding window fashion. Magnetometer information is currently
only used for initialisation, while the estimation itself works without
magnetometers. The method was tested on simulated, as well as, on real data,
captured from a lower body configuration.


title:
Lagrange inversion formula, Laguerre polynomials and the free unitary
  Brownian motion

abstract:
  This paper is devoted to the computations of some relevant quantities
associated with the free unitary Brownian motion. Using the Lagrange inversion
formula, we first derive an explicit expression for its alternating star
cumulants of even lengths and relate them to those having odd lengths by means
of a summation formula for the free cumulants with product as entries. Next, we
use again this formula together with a generating series for Laguerre
polynomials in order to compute the Taylor coefficients of the reciprocal of
the $R$-transform of the free Jacobi process associated with a single
projection of rank $1/2$ and those of the $S$-transform as well. This
generating series lead also to the Taylor expansions of the Schur function of
the spectral distribution of the free unitary Brownian motion and of its first
iterate.


title: The perturbative QCD gradient flow to three loops

abstract:
  The gradient flow in QCD is treated perturbatively through
next-to-next-to-leading order in the strong coupling constant. The evaluation
of the relevant momentum and flow-time integrals is described, including
various means of validation. For the vacuum expectation value of the action
density, which turns out to be a useful quantity in lattice calculations, we
find a very well-behaved perturbative series through NNLO. Quark mass effects
are taken into account through NLO. The theoretical uncertainty due to
renormalization scale variation is significantly reduced with respect to LO and
NLO, as long as the flow time is smaller than about 0.1 fm.


title: DNest4: Diffusive Nested Sampling in C++ and Python

abstract:
  In probabilistic (Bayesian) inferences, we typically want to compute
properties of the posterior distribution, describing knowledge of unknown
quantities in the context of a particular dataset and the assumed prior
information. The marginal likelihood, also known as the "evidence", is a key
quantity in Bayesian model selection. The Diffusive Nested Sampling algorithm,
a variant of Nested Sampling, is a powerful tool for generating posterior
samples and estimating marginal likelihoods. It is effective at solving complex
problems including many where the posterior distribution is multimodal or has
strong dependencies between variables. DNest4 is an open source (MIT licensed),
multi-threaded implementation of this algorithm in C++11, along with associated
utilities including: i) RJObject, a class template for finite mixture models,
(ii) A Python package allowing basic use without C++ coding, and iii)
Experimental support for models implemented in Julia. In this paper we
demonstrate DNest4 usage through examples including simple Bayesian data
analysis, finite mixture models, and Approximate Bayesian Computation.


title:
Deciding Equivalence of Linear Tree-to-Word Transducers in Polynomial
  Time

abstract:
  We show that the equivalence of deterministic linear top-down tree-to-word
transducers is decidable in polynomial time. Linear tree-to-word transducers
are non-copying but not necessarily order-preserving and can be used to express
XML and other document transformations. The result is based on a partial normal
form that provides a basic characterization of the languages produced by linear
tree-to-word transducers.


title:
Euler characteristic of analogues of a Deligne-Lusztig variety for
  $GL_n$

abstract:
  In this paper we give a combinatorial formula to calculate the Euler
characteristic of an analogue of a Deligne-Lusztig variety if we replace
Frobenius morphism with conjugation by an element for $GL_n$. The main theorem
states that it only depends on the unipotent part of the Jordan decomposition
of an element and the conjugacy class in the Weyl group. Also it generalizes
the formula of the Euler characteristic of a Springer fiber for type A.


title:
$\eta_{c}$ Elastic and Transition Form Factors: Contact Interaction and
  Algebraic Model

abstract:
  For the flavor-singlet heavy quark system of charmonia in the pseudoscalar
($\eta_c(1S)$) channel, we calculate the elastic (EFF) and transition form
factors (TFF) ($\eta_c(1S) \rightarrow \gamma \gamma^*$) for a wide range of
photon momentum transfer squared ($Q^2$). The framework for this analysis is
provided by a symmetry-preserving Schwinger-Dyson equation (SDE) and
Bethe-Salpeter equation (BSE) treatment of a vector$\times$vector contact
interaction (CI). We also employ an algebraic model (AM), developed earlier to
describe the light quark systems. It correctly correlates infrared and
ultraviolet dynamics of quantum chromodynamics (QCD).
  The CI results agree with the lattice data for low $Q^2$. For $Q^2 \geqslant
Q_0^2$, the results start deviating from the lattice results by more than $20
\%$. $Q_0^2 \thickapprox 2.5 {\rm GeV}^2$ for the EFF and $\thickapprox 25 {\rm
GeV}^2$ for the TFF. We also present the results for the EFF, TFF as well as
$\eta_c(1S)$ parton distribution amplitude for the AM. Wherever the comparison
is possible, these results are in excellent agreement with the lattice,
perturbative QCD, the results obtained through an SDE-BSE study, employing
refined truncations, as well as the experimental findings of the BABAR
experiment.


title: On a property discovered by Xavier Grandsart

abstract:
  We give a simple proof of the property discovered by Xavier Grandsart: let
$W$ be a circular binary word; then the differences in the number of occurences
$|W|_{0011}-|W|_{1100}$, $ |W|_{1101}-|W|_{1011}$ , $|W|_{1010}-|W|_{0101}$ and
$|W|_{0100}-|W|_{0010}$ are equal.


title: Nature of a single doped hole in two-leg Hubbard and $t$-$J$ ladders

abstract:
  In this paper, we have systematically studied the single hole problem in
two-leg Hubbard and $t$-$J$ ladders by large-scale density-matrix
renormalization group calculations. We found that the doped hole in both models
behaves similarly with each other while the three-site correlated hopping term
is not important in determining the ground state properties. For more insights,
we have also calculated the elementary excitations, i.e., the energy gaps to
the excited states of the system. In the strong rung limit, we found that the
doped hole behaves as a Bloch quasiparticle in both systems where the spin and
charge of the doped hole are tightly bound together. In the isotropic limit,
while the hole still behaves like a quasiparticle in the long-wavelength limit,
its spin and charge components are only loosely bound together with a
nontrivial mutual statistics inside the quasiparticle. Our results show that
this mutual statistics can lead to an important residual effect which
dramatically changes the local structure of the ground state wavefunction.


title:
A note on continuity of magnetization at criticality for the
  ferromagnetic Ising model on amenable quasi-transitive graphs with
  exponential growth

abstract:
  The purpose of this modest note is to point out that the proof of the recent
result of Huchcroft concerning continuity of phase transition in Bernoulli
percolation is applicable to the setting of the Ising model with free boundary
condition. This observation, together with a recent result of Aizenman,
Duminil-Copin, and Sidoravicius implies that the Ising model on amenable
quasi-transitive graph with exponential growth undergoes a second order phase
transition.


title:
Percolation on trees as a Brownian excursion: from Gaussian to
  Kolmogorov-Smirnov to Exponential statistics

abstract:
  We calculate the distribution of the size of the percolating cluster on a
tree in the subcritical, critical and supercritical phase. We do this by
exploiting a mapping between continuum trees and Brownian excursions, and
arrive at a diffusion equation with suitable boundary conditions. The exact
solution to this equation can be conveniently represented as a characteristic
function, from which the following distributions are clearly visible: Gaussian
(subcritical), Kolmogorov-Smirnov (critical) and exponential (supercritical).
In this way we provide an intuitive explanation for the result reported in R.
Botet and M. Ploszajczak, Phys. Rev. Lett 95, 185702 (2005) for critical
percolation.


title:
Adaptive Local Window for Level Set Segmentation of CT and MRI Liver
  Lesions

abstract:
  We propose a novel method, the adaptive local window, for improving level set
segmentation technique. The window is estimated separately for each contour
point, over iterations of the segmentation process, and for each individual
object. Our method considers the object scale, the spatial texture, and changes
of the energy functional over iterations. Global and local statistics are
considered by calculating several gray level co-occurrence matrices. We
demonstrate the capabilities of the method in the domain of medical imaging for
segmenting 233 images with liver lesions. To illustrate the strength of our
method, those images were obtained by either Computed Tomography or Magnetic
Resonance Imaging. Moreover, we analyzed images using three different energy
models. We compare our method to a global level set segmentation and to local
framework that uses predefined fixed-size square windows. The results indicate
that our proposed method outperforms the other methods in terms of agreement
with the manual marking and dependence on contour initialization or the energy
model used. In case of complex lesions, such as low contrast lesions,
heterogeneous lesions, or lesions with a noisy background, our method shows
significantly better segmentation with an improvement of 0.25+- 0.13 in Dice
similarity coefficient, compared with state of the art fixed-size local windows
(Wilcoxon, p < 0.001).


title:
ContaminatedMixt: An R Package for Fitting Parsimonious Mixtures of
  Multivariate Contaminated Normal Distributions

abstract:
  We introduce the R package ContaminatedMixt, conceived to disseminate the use
of mixtures of multivariate contaminated normal distributions as a tool for
robust clustering and classification under the common assumption of
elliptically contoured groups. Thirteen variants of the model are also
implemented to introduce parsimony. The expectation-conditional maximization
algorithm is adopted to obtain maximum likelihood parameter estimates, and
likelihood-based model selection criteria are used to select the model and the
number of groups. Parallel computation can be used on multicore PCs and
computer clusters, when several models have to be fitted. Differently from the
more popular mixtures of multivariate normal and t distributions, this approach
also allows for automatic detection of mild outliers via the maximum a
posteriori probabilities procedure. To exemplify the use of the package,
applications to artificial and real data are presented.


title: Optical Characterization of PtSi/Si by Spectroscopic Ellipsometry

abstract:
  We report optical characterization of PtSi films for thermoelectric device
applications by nondestructive spectroscopic ellipsometry (SE). Pt monolayer
and Pt-Si multilayer which consists of 3 pairs of Pt and Si layers were
deposited on p-doped-silicon substrates by sputtering method and then rapid
annealing process was done to form PtSi films through intermixing of Pt and Si
atoms at the interface. Pseudodielectric function data <{\epsilon}> =
<{\epsilon}1> + i<{\epsilon}2> of the PtSi/Si samples were obtained from 1.12
to 6.52 eV by using spectroscopic ellipsometry. Employing Tauc-Lorentz and
Drude models, the dielectric function ({\epsilon}) of PtSi films were
determined. We found that the composition ratio of Pt:Si is nearly 1:1 for PtSi
monolayer and we observed transitions between occupied and unoccupied states in
Pt 5d states. We also observed formation of PtSi layers in Pt-Si multilayer
sample. The SE results were confirmed by the transmission electron microscopy
and energy dispersive X-ray spectroscopy.


title:
New Permutation Trinomials From Niho Exponents over Finite Fields with
  Even Characteristic

abstract:
  In this paper, a class of permutation trinomials of Niho type over finite
fields with even characteristic is further investigated. New permutation
trinomials from Niho exponents are obtained from linear fractional polynomials
over finite fields, and it is shown that the presented results are the
generalizations of some earlier works.


title: Dispersion relations for unphysical particles

abstract:
  Generalized dispersion relations are discussed for unphysical particles, e.g.
confined degrees of freedom that are not present in the physical spectra but
can give rise to observable bound states. While in general the propagator of
the unphysical particles can have complex poles and cannot be reconstructed
from the knowledge of the imaginary part, under reasonable assumptions the
missing piece of information is shown to be in the rational function that
contains the poles and must be added to the integral representation. For pure
Yang-Mills theory, the rational part and the spectral term are identified in
the explicit analytical expressions provided by the massive expansion of the
gluon propagator. The multi particle spectral term turns out to be very small
and the simple rational part provides, from first principles, an approximate
propagator that is equivalent to the tree-level result of simple
phenomenological models like the refined Gribov-Zwanziger model.


title: Double ramification cycles on the moduli spaces of admissible covers

abstract:
  We derive a formula for the virtual class of the moduli space of rubber maps
to $[\mathbb{P}^1/G]$ pushed forward to the moduli space of stable maps to
$BG$. As an application, we show that the Gromov-Witten theory of
$[\mathbb{P}^1/G]$ relative to $0$ and $\infty$ are determined by known
calculations.


title:
Rate of convergence of attractors for semilinear singularly perturbed
  problems: scalar parabolic equations with localized large diffusion

abstract:
  In this paper we study the asymptotic nonlinear dynamics of scalar semilinear
parabolic problems reaction-diffusion type when the diffusion coefficient
becomes large in a subregion which is interior to the domain. We obtain, under
suitable assumptions, that the family of attractors behaves continuously and we
exhibit the rate of convergence. An accurate description of localized large
diffusion is necessary.


title:
Rate of Convergence of Attractors for Singularly Perturbed Semilinear
  Problems

abstract:
  We exhibit a class of singularly perturbed parabolic problems which the
asymptotic behavior can be described by a system of ordinary differential
equation. We estimate the convergence of attractors in the Hausdorff metric by
rate of convergence of resolvent operators. Application to spatial
homogenization and large diffusion except in a neighborhood of a point will be
considered.


title: Remez-type inequalities for the hyperbolic cross polynomials

abstract:
  In this paper we study the Remez-type inequalities for trigonometric
polynomials with harmonics from hyperbolic crosses. The interrelation between
the Remez and Nikolskii inequalities for individual functions and its
applications are discussed.


title: Human Centred Object Co-Segmentation

abstract:
  Co-segmentation is the automatic extraction of the common semantic regions
given a set of images. Different from previous approaches mainly based on
object visuals, in this paper, we propose a human centred object
co-segmentation approach, which uses the human as another strong evidence. In
order to discover the rich internal structure of the objects reflecting their
human-object interactions and visual similarities, we propose an unsupervised
fully connected CRF auto-encoder incorporating the rich object features and a
novel human-object interaction representation. We propose an efficient learning
and inference algorithm to allow the full connectivity of the CRF with the
auto-encoder, that establishes pairwise relations on all pairs of the object
proposals in the dataset. Moreover, the auto-encoder learns the parameters from
the data itself rather than supervised learning or manually assigned parameters
in the conventional CRF. In the extensive experiments on four datasets, we show
that our approach is able to extract the common objects more accurately than
the state-of-the-art co-segmentation algorithms.


title: Additive Function-on-Function Regression

abstract:
  We study additive function-on-function regression where the mean response at
a particular time point depends on the time point itself as well as the entire
covariate trajectory. We develop a computationally efficient estimation
methodology based on a novel combination of spline bases with an eigenbasis to
represent the trivariate kernel function. We discuss prediction of a new
response trajectory, propose an inference procedure that accounts for total
variability in the predicted response curves, and construct pointwise
prediction intervals. The estimation/inferential procedure accommodates
realistic scenarios such as correlated error structure as well as sparse and/or
irregular designs. We investigate our methodology in finite sample size through
simulations and two real data applications.


title: Engaging Learning Analytics in MOOCS: the good, the bad, and the ugly

abstract:
  Learning Analytics is an emerging field in the vast areas of Educational
Technology and Technology Enhanced Learning (TEL). It provides tools and
techniques that offer researchers the ability to analyze, study, and benchmark
institutions, learners and teachers as well as online learning environments
such as MOOCs. Massive Open Online Courses (MOOCs) are considered to be a very
active and an innovative form of bringing educational content to a broad
community. Due to the reasons of being free and accessible to the public, MOOCs
attracted a large number of heterogeneous learners who differ in education
level, gender, and age. However, there are pressing demands to adjust the
quality of the hosted courses, as well as controlling the high dropout ratio
and the lack of interaction. With the help of Learning Analytics, it is
possible to contain such issues. In this publication, we discuss the principles
of engaging Learning Analytics in MOOCs learning environments and review its
potential and capabilities (the good), constraints (the bad), and fallacy
analytics (the ugly) based on our experience in last years.


title: Neural Belief Tracker: Data-Driven Dialogue State Tracking

abstract:
  One of the core components of modern spoken dialogue systems is the belief
tracker, which estimates the user's goal at every step of the dialogue.
However, most current approaches have difficulty scaling to larger, more
complex dialogue domains. This is due to their dependency on either: a) Spoken
Language Understanding models that require large amounts of annotated training
data; or b) hand-crafted lexicons for capturing some of the linguistic
variation in users' language. We propose a novel Neural Belief Tracking (NBT)
framework which overcomes these problems by building on recent advances in
representation learning. NBT models reason over pre-trained word vectors,
learning to compose them into distributed representations of user utterances
and dialogue context. Our evaluation on two datasets shows that this approach
surpasses past limitations, matching the performance of state-of-the-art models
which rely on hand-crafted semantic lexicons and outperforming them when such
lexicons are not provided.


title:
The Vop\v{e}nka principle is inequivalent to but conservative over the
  Vop\v{e}nka scheme

abstract:
  The Vop\v{e}nka principle, which asserts that every proper class of
first-order structures in a common language admits an elementary embedding
between two of its members, is not equivalent over GBC to the first-order
Vop\v{e}nka scheme, which makes the Vop\v{e}nka assertion only for the
first-order definable classes of structures. Nevertheless, the two Vop\v{e}nka
axioms are equiconsistent and they have exactly the same first-order
consequences in the language of set theory. Specifically, GBC plus the
Vop\v{e}nka principle is conservative over ZFC plus the Vop\v{e}nka scheme for
first-order assertions in the language of set theory.


title:
Uniform cover inequalities for the volume of coordinate sections and
  projections of convex bodies

abstract:
  The classical Loomis-Whitney inequality and the uniform cover inequality of
Bollob\'{a}s and Thomason provide lower bounds for the volume of a compact set
in terms of its lower dimensional coordinate projections. We provide further
extensions of these inequalities in the setting of convex bodies. We also
establish the corresponding dual inequalities for coordinate sections; these
uniform cover inequalities for sections may be viewed as extensions of Meyer's
dual Loomis-Whitney inequality.


title: Relativistic calculations of angular dependent photoemission time delay

abstract:
  Angular dependence of photoemission time delay for the valence $np_{3/2}$ and
$np_{1/2}$ subshells of Ar, Kr and Xe is studied in the dipole relativistic
random phase approximation. Strong angular anisotropy of the time delay is
reproduced near respective Cooper minima while the spin-orbit splitting affects
the time delay near threshold.


title:
A Photometrically and Spectroscopically Confirmed Population of Passive
  Spiral Galaxies

abstract:
  We have identified a population of passive spiral galaxies from photometry
and integral field spectroscopy. We selected z<0.035 spiral galaxies that have
WISE colours consistent with little mid-infrared emission from warm dust.
Matched aperture photometry of 51 spiral galaxies in ultraviolet, optical and
mid-infrared show these galaxies have colours consistent with passive galaxies.
Six galaxies form a spectroscopic pilot study and were observed using the
Wide-Field Spectrograph (WiFeS) to check for signs of nebular emission from
star formation. We see no evidence of substantial nebular emission found in
previous red spiral samples. These six galaxies possess absorption-line spectra
with 4000\AA\ breaks consistent with an average luminosity-weighted age of 2.3
Gyr. Our photometric and IFU spectroscopic observations confirm the existence
of a population of local passive spiral galaxies, implying that transformation
into early-type morphologies is not required for the quenching of star
formation.


title: Graphs with obstacle number greater than one

abstract:
  An \emph{obstacle representation} of a graph $G$ is a straight-line drawing
of $G$ in the plane together with a collection of connected subsets of the
plane, called \emph{obstacles}, that block all non-edges of $G$ while not
blocking any of the edges of $G$. The \emph{obstacle number} obs$(G)$ is the
minimum number of obstacles required to represent $G$.
  We study the structure of graphs with obstacle number greater than one. We
show that the icosahedron has obstacle number $2$, thus answering a question of
Alpert, Koch, \& Laison asking whether all planar graphs have obstacle number
at most $1$. We also show that the $1$-skeleton of a related polyhedron, the
\emph{gyroelongated $4$-dipyramid}, has obstacle number $2$. The order of this
graph is $10$, which is also the order of the smallest known graph with
obstacle number $2$.
  Some of our methods involve instances of the Satisfiability problem, we make
use of various "SAT solvers" in order to produce computer-assisted proofs.


title:
Retrieving and Ranking Similar Questions from Question-Answer Archives
  Using Topic Modelling and Topic Distribution Regression

abstract:
  Presented herein is a novel model for similar question ranking within
collaborative question answer platforms. The presented approach integrates a
regression stage to relate topics derived from questions to those derived from
question-answer pairs. This helps to avoid problems caused by the differences
in vocabulary used within questions and answers, and the tendency for questions
to be shorter than answers. The performance of the model is shown to outperform
translation methods and topic modelling (without regression) on several
real-world datasets.


title: MITRE at SemEval-2016 Task 6: Transfer Learning for Stance Detection

abstract:
  We describe MITRE's submission to the SemEval-2016 Task 6, Detecting Stance
in Tweets. This effort achieved the top score in Task A on supervised stance
detection, producing an average F1 score of 67.8 when assessing whether a tweet
author was in favor or against a topic. We employed a recurrent neural network
initialized with features learned via distant supervision on two large
unlabeled datasets. We trained embeddings of words and phrases with the
word2vec skip-gram method, then used those features to learn sentence
representations via a hashtag prediction auxiliary task. These sentence vectors
were then fine-tuned for stance detection on several hundred labeled examples.
The result was a high performing system that used transfer learning to maximize
the value of the available training data.


title: $SO(10)$ thick branes and perturbative stability

abstract:
  Three self-gravitating $SO(10)$ domain walls in five dimensions are obtained
and their properties are analyzed. These non-abelian domain walls interpolate
between AdS${}_5$ spacetimes with different embedding of $SU(5)$ in $SO(10)$
and they can be distinguished, among other features, by the unbroken group on
each wall, being either $SO(10)$, $SO(6)\otimes SU(2)\otimes U(1)/Z_2$ or
$SU(4)\otimes SO(2)\otimes U(1)/Z_4$. We show that, unlike Minkowskian
versions, the curved scenarios are perturbatively stable due to the
gravitational capture of scalar fluctuations associated to the residual
orthogonal subgroup in the core of the walls. These stabilizer modes are
additional to the four-dimensional Nambu-Goldstone states found in two of the
three gravitational sceanarios.


title:
Charge Stripper Effects on Beam Optics in 180-degree Bending Section of
  RISP Linac

abstract:
  The RAON, a superconducting linear accelerator for RISP (Rare Isotope Science
Project), will use a charge stripper in order to increase the charge states of
the heavy ions for effective acceleration in the higher energy part of the
linac. The charge stripper affects the beam qualities by scattering when the
heavy ions go through the charge stripper. Moreover we have to select and
accelerate proper charge states between 77+ and 81+ for uranium beam case in
order to satisfy the beam power requirement at an IF (Inflight Fragmentation)
target. This work focuses on the beam optics affected by the charge stripper in
the 180-dgree bending section.


title: Topics and problems on favorite sites of random walks

abstract:
  In this article, we study special points of a simple random walk and a
Gaussian free field, such as (nearly) favorite points, late points and high
points. In section $2$, we extend results of [19] and suggest open problems for
$d=2$. In section $3$, we give a survey on the geometric structures of (nearly)
favorite points and late points of a simple random walk and high points of a
Gaussian free field in two dimension.


title:
Unsupervised Non Linear Dimensionality Reduction Machine Learning
  methods applied to Multiparametric MRI in cerebral ischemia: Preliminary
  Results

abstract:
  The evaluation and treatment of acute cerebral ischemia requires a technique
that can determine the total area of tissue at risk for infarction using
diagnostic magnetic resonance imaging (MRI) sequences. Typical MRI data sets
consist of T1- and T2-weighted imaging (T1WI, T2WI) along with advanced MRI
parameters of diffusion-weighted imaging (DWI) and perfusion weighted imaging
(PWI) methods. Each of these parameters has distinct radiological-pathological
meaning. For example, DWI interrogates the movement of water in the tissue and
PWI gives an estimate of the blood flow, both are critical measures during the
evolution of stroke. In order to integrate these data and give an estimate of
the tissue at risk or damaged, we have developed advanced machine learning
methods based on unsupervised non-linear dimensionality reduction (NLDR)
techniques. NLDR methods are a class of algorithms that uses mathematically
defined manifolds for statistical sampling of multidimensional classes to
generate a discrimination rule of guaranteed statistical accuracy and they can
generate a two- or three-dimensional map, which represents the prominent
structures of the data and provides an embedded image of meaningful
low-dimensional structures hidden in their high-dimensional observations. In
this manuscript, we develop NLDR methods on high dimensional MRI data sets of
preclinical animals and clinical patients with stroke. On analyzing the
performance of these methods, we observed that there was a high of similarity
between multiparametric embedded images from NLDR methods and the ADC map and
perfusion map. It was also observed that embedded scattergram of abnormal
(infarcted or at risk) tissue can be visualized and provides a mechanism for
automatic methods to delineate potential stroke volumes and early tissue at
risk.


title: On integrals associated with the Free particle wave packet

abstract:
  We discuss some properties of integrals associated with the free particle
wave packet, $\psi(x,t),$ which are solutions to the time-dependent
Schr$\ddot{o}$dinger equation for a free particle in one dimension. Some
noteworthy discussion is made in relation to integrals which have appeared in
the literature. We also obtain formulas for half-integer arguments of the
Riemann zeta function.


title: The super spanning connectivity of arrangement graph

abstract:
  A $k$-container $C(u, v)$ of a graph $G$ is a set of $k$ internally disjoint
paths between $u$ and $v$. A $k$-container $C(u, v)$ of $G$ is a
$k^*$-container if it is a spanning subgraph of $G$. A graph $G$ is
$k^*$-connected if there exists a $k^*$-container between any two different
vertices of G. A $k$-regular graph $G$ is super spanning connected if $G$ is
$i^*$-container for all $1\le i\le k$. In this paper, we prove that the
arrangement graph $A_{n, k}$ is super spanning connected if $n\ge 4$ and
$n-k\ge 2$.


title: Univoque bases and Hausdorff dimension

abstract:
  Given a positive integer $M$ and a real number $q >1$, a \emph{$q$-expansion}
of a real number $x$ is a sequence $(c_i)=c_1c_2\cdots$ with $(c_i) \in
\{0,\ldots,M\}^\infty$ such that \[x=\sum_{i=1}^{\infty} c_iq^{-i}.\]
  It is well known that if $q \in (1,M+1]$, then each $x \in
I_q:=\left[0,M/(q-1)\right]$ has a $q$-expansion. Let
$\mathcal{U}=\mathcal{U}(M)$ be the set of \emph{univoque bases} $q>1$ for
which $1$ has a unique $q$-expansion.
  The main object of this paper is to provide new characterizations of
$\mathcal{U}$ and to show that the Hausdorff dimension of the set of numbers $x
\in I_q$ with a unique $q$-expansion changes the most if $q$ "crosses" a
univoque base.
  Denote by $\mathcal{B}_2=\mathcal{B}_2(M)$ the set of $q \in (1,M+1]$ such
that there exist numbers having precisely two distinct $q$-expansions. As a
by-product of our results, we obtain an answer to a question of Sidorov (2009)
and prove that \[\dim_H(\mathcal{B}_2\cap(q',q'+\delta))>0\quad\textrm{for
any}\quad \delta>0,\] where $q'=q'(M)$ is the Komornik-Loreti constant.


title: Operator systems and convex sets with many normal cones

abstract:
  The state space of an operator system of $n$-by-$n$ matrices has, in a sense,
many normal cones. Merely this convex geometrical property implies smoothness
qualities and a clustering property of exposed faces. The latter holds since
each exposed face is an intersection of maximal exposed faces. An isomorphism
translates these results to the lattice of ground state projections of the
operator system. We work on minimizing the assumptions under which a convex set
has the mentioned properties.


title:
Singular limits and properties of solutions of some degenerate elliptic
  and parabolic equations

abstract:
  Let $n\geq 3$, $0\le m<\frac{n-2}{n}$, $\rho_1>0$,
$\beta>\beta_0^{(m)}=\frac{m\rho_1}{n-2-nm}$,
$\alpha_m=\frac{2\beta+\rho_1}{1-m}$ and $\alpha=2\beta+\rho_1$. For any
$\lambda>0$, we prove the uniqueness of radially symmetric solution $v^{(m)}$
of $\La(v^m/m)+\alpha_m v+\beta x\cdot\nabla v=0$, $v>0$, in
$\R^n\setminus\{0\}$ which satisfies $\lim_{|x|\to
0}|x|^{\frac{\alpha_m}{\beta}}v^{(m)}(x)=\lambda^{-\frac{\rho_1}{(1-m)\beta}}$
and obtain higher order estimates of $v^{(m)}$ near the blow-up point $x=0$. We
prove that as $m\to 0^+$, $v^{(m)}$ converges uniformly in $C^2(K)$ for any
compact subset $K$ of $\R^n\setminus\{0\}$ to the solution $v$ of $\La\log
v+\alpha v+\beta x\cdot\nabla v=0$, $v>0$, in $\R^n\bs\{0\}$, which satisfies
$\lim_{|x|\to
0}|x|^{\frac{\alpha}{\beta}}v(x)=\lambda^{-\frac{\rho_1}{\beta}}$. We also
prove that if the solution $u^{(m)}$ of $u_t=\Delta (u^m/m)$, $u>0$, in
$(\R^n\setminus\{0\})\times (0,T)$ which blows up near $\{0\}\times (0,T)$ at
the rate $|x|^{-\frac{\alpha_m}{\beta}}$ satisfies some mild growth condition
on $(\R^n\setminus\{0\})\times (0,T)$, then as $m\to 0^+$, $u^{(m)}$ converges
uniformly in $C^{2+\theta,1+\frac{\theta}{2}}(K)$ for some constant $\theta\in
(0,1)$ and any compact subset $K$ of $(\R^n\setminus\{0\})\times (0,T)$ to the
solution of $u_t=\La\log u$, $u>0$, in $(\R^n\setminus\{0\})\times (0,T)$. As a
consequence of the proof we obtain existence of a unique radially symmetric
solution $v^{(0)}$ of $\La \log v+\alpha v+\beta x\cdot\nabla v=0$, $v>0$, in
$\R^n\setminus\{0\}$, which satisfies $\lim_{|x|\to
0}|x|^{\frac{\alpha}{\beta}}v(x)=\lambda^{-\frac{\rho_1}{\beta}}$.


title:
Weighted norm inequalities of (1,q)-type for integral and fractional
  maximal operators

abstract:
  We study weighted norm inequalities of $(1,q)$- type for $0<q<1$, $\Vert
\mathbf{G} \nu \Vert_{L^q(\Omega, d \sigma)} \le C \, \Vert \nu \Vert, \quad
\text{for all positive measures $\nu$ in $\Omega$},$ along with their weak-type
counterparts, where $\Vert \nu \Vert=\nu(\Omega)$, and $G$ is an integral
operator with nonnegative kernel, $\mathbf{G} \nu(x) = \int_\Omega G(x, y) d
\nu(y).$
  These problems are motivated by sublinear elliptic equations in a domain
$\Omega\subset\mathbb{R}^n$ with non-trivial Green's function $G(x, y)$
associated with the Laplacian, fractional Laplacian, or more general elliptic
operator. We also treat fractional maximal operators $M_\alpha$ ($0\le
\alpha<n$) on $\mathbb{R}^n$, and characterize strong- and weak-type
$(1,q)$-inequalities for $M_\alpha$ and more general maximal operators, as well
as $(1,q)$-Carleson measure inequalities for Poisson integrals.


title:
Error suppression for Hamiltonian-based quantum computation using
  subsystem codes

abstract:
  We present general conditions for quantum error suppression for
Hamiltonian-based quantum computation using subsystem codes. This involves
encoding the Hamiltonian performing the computation using an error detecting
subsystem code and the addition of a penalty term that commutes with the
encoded Hamiltonian. The scheme is general and includes the stabilizer
formalism of both subspace and subsystem codes as special cases. We derive
performance bounds and show that complete error suppression results in the
large penalty limit. To illustrate the power of subsystem-based error
suppression, we introduce fully 2-local constructions for protection of the
swap gate of adiabatic gate teleportation and the Ising chain in a transverse
field.


title: Pluriclosed flow on manifolds with globally generated bundles

abstract:
  We show global existence and convergence results for the pluriclosed flow on
manifolds for which certain naturally associated tensor bundles are globally
generated.


title:
Understanding the Results of Electrostatics Calculations: Visualizing
  Molecular 'Isopotential' Surfaces

abstract:
  This document attempts to clarify potential confusion regarding
electrostatics calculations, specifically in the context of biomolecular
structure and specifically as regards the units typically used to
contour/visualize isopotential surfaces, potentials mapped onto molecular
solvent-accessible surfaces, etc.


title: Deep Image Homography Estimation

abstract:
  We present a deep convolutional neural network for estimating the relative
homography between a pair of images. Our feed-forward network has 10 layers,
takes two stacked grayscale images as input, and produces an 8 degree of
freedom homography which can be used to map the pixels from the first image to
the second. We present two convolutional neural network architectures for
HomographyNet: a regression network which directly estimates the real-valued
homography parameters, and a classification network which produces a
distribution over quantized homographies. We use a 4-point homography
parameterization which maps the four corners from one image into the second
image. Our networks are trained in an end-to-end fashion using warped MS-COCO
images. Our approach works without the need for separate local feature
detection and transformation estimation stages. Our deep models are compared to
a traditional homography estimator based on ORB features and we highlight the
scenarios where HomographyNet outperforms the traditional technique. We also
describe a variety of applications powered by deep homography estimation, thus
showcasing the flexibility of a deep learning approach.


title: Maximal green sequences for quivers of finite mutation type

abstract:
  In general, the existence of a maximal green sequence is not mutation
invariant. In this paper we show that it is in fact mutation invariant for
cluster quivers of finite mutation type. In particular, we show that a mutation
finite cluster quiver has a maximal green sequence unless it arises from a
once-punctured closed marked surface, or one of the two quivers in the mutation
class of X7. We develop a procedure to explicitly find maximal green sequences
for cluster quivers associated to arbitrary triangulations of closed marked
surfaces with at least two punctures. As a corollary, it follows that any
triangulation of a marked surface with boundary has a maximal green sequence.
We also compute explicit maximal green sequences for exceptional quivers of
finite mutation type.


title: Computing the Optimal Longest Queue Length in Torus Networks

abstract:
  A collection of $k$ mobile agents is arbitrarily deployed in the edges of a
directed torus network where agents perpetually move to the successor edge.
Each node has a switch that allows one agent of the two incoming edges to pass
to its successor edge in every round. The goal is to obtain a switch scheduling
to reach and maintain a configuration where the longest queue length is
minimum. We consider a synchronous system. We use the concept of conflict
graphs to model the local conflicts that occur with incident links. We show
that there does not exist an algorithm that can reduce the number of agents in
any conflict cycle of the conflict graph providing that all the links have at
least 2 agents at every round. Hence, the lower bound is at least the average
queue length of the conflict cycle with the maximum average queue length. Next,
we present a centralized algorithm that computes a strategy in $O(n\log n)$
time for each round that attains the optimal queue length in $O(\sigma n)$
rounds where $n$ is the number of nodes in the network and $\sigma$ is the
standard deviations of the queue lengths in the initial setting. Our technique
is based on network flooding on conflict graphs. Next, we consider a
distributed system where nodes have access to the length of their queues and
use communication to self-coordinate with nearby nodes. We present a local
algorithm using only the information of the queue lengths at distance two. We
show that the algorithm attains the optimal queue length in $O(\sigma
C_{max}^2)$ rounds where $C_{max}$ is the length of the longest conflict cycle
with the maximum average queue length.


title:
Representation Crossed Category of Group-cograded Multiplier Hopf
  Algebras

abstract:
  Let $A=\bigoplus_{p\in G}A_{p}$ be a multiplier Hopf $T$-coalgebra over a
group $G$, in this paper we give the definition of the crossed left
$A$-$G$-modules and show that the category of crossed left $A$-$G$-modules is a
monoidal category. Finally we show that a family of multipliers $R = \{R_{p, q}
\in M(A_{p}\otimes A_{q})\}_{p, q\in G}$ is a quasitriangular structure of a
multiplier $T$-coalgebra $A$ if and only if the crossed left $A$-$G$-module
category over $A$ is a braided monoidal category with the braiding $c$ defined
by $R$, generalizing the main results in \cite{ZCL11} to the more general
framework of multiplier Hopf algebras.


title: Open-Set Support Vector Machines

abstract:
  Often, when dealing with real-world recognition problems, we do not need, and
often cannot have, knowledge of the entire set of possible classes that might
appear during operational testing. In such cases, we need to think of robust
classification methods able to deal with the "unknown" and properly reject
samples belonging to classes never seen during training. Notwithstanding,
existing classifiers to date were mostly developed for the closed-set scenario,
i.e., the classification setup in which it is assumed that all test samples
belong to one of the classes with which the classifier was trained. In the
open-set scenario, however, a test sample can belong to none of the known
classes and the classifier must properly reject it by classifying it as
unknown. In this work, we extend upon the well-known Support Vector Machines
(SVM) classifier and introduce the Open-Set Support Vector Machines (OSSVM),
which is suitable for recognition in open-set setups. OSSVM balances the
empirical risk and the risk of the unknown and ensures that the region of the
feature space in which a test sample would be classified as known (one of the
known classes) is always bounded, ensuring a finite risk of the unknown. In
this work, we also highlight the properties of the SVM classifier related to
the open-set scenario, and provide necessary and sufficient conditions for an
RBF SVM to have bounded open-space risk.


title: Tuning-Free Heterogeneity Pursuit in Massive Networks

abstract:
  Heterogeneity is often natural in many contemporary applications involving
massive data. While posing new challenges to effective learning, it can play a
crucial role in powering meaningful scientific discoveries through the
understanding of important differences among subpopulations of interest. In
this paper, we exploit multiple networks with Gaussian graphs to encode the
connectivity patterns of a large number of features on the subpopulations. To
uncover the heterogeneity of these structures across subpopulations, we suggest
a new framework of tuning-free heterogeneity pursuit (THP) via large-scale
inference, where the number of networks is allowed to diverge. In particular,
two new tests, the chi-based test and the linear functional-based test, are
introduced and their asymptotic null distributions are established. Under mild
regularity conditions, we establish that both tests are optimal in achieving
the testable region boundary and the sample size requirement for the latter
test is minimal. Both theoretical guarantees and the tuning-free feature stem
from efficient multiple-network estimation by our newly suggested approach of
heterogeneous group square-root Lasso (HGSL) for high-dimensional
multi-response regression with heterogeneous noises. To solve this convex
program, we further introduce a tuning-free algorithm that is scalable and
enjoys provable convergence to the global optimum. Both computational and
theoretical advantages of our procedure are elucidated through simulation and
real data examples.


title:
Phenomenology of an $SU(2)_1 \times SU(2)_2 \times U(1)_Y$ model at the
  LHC

abstract:
  We investigate the implications of a minimal $SU(2)$ gauge symmetry extension
of the standard model at the LHC. To achieve the spontaneous symmetry breaking,
a heavy Higgs doublet of the $SU(2)$ is introduced. To obtain an anomaly free
model and the decays of new charged gauge bosons, we include a vector-like
quark doublet. We also employ a real scalar boson to dictate the heavy Higgs
production via the gluon-gluon fusion processes. It is found that the new gauge
coupling and the masses of new gauge bosons can be strictly bounded by the
electroweak $\rho$-parameter and dilepton resonance experiments at the LHC. It
is found that due to the new charged gauge boson enhancement, the cross
sections for a heavy scalar boson to diphoton channel measured by ATLAS and CMS
can be easily satisfied when the values of Yukawa couplings are properly taken.
Furthermore, by adopting event simulation, we find that the significance of
$pp\to (\gamma \gamma)_H+{\rm jet}$, where the diphoton is from the heavy Higgs
decay, can be over $4\sigma$ when the luminosity is above 60 fb$^{-1}$.


title:
The factorization theory of Thom spectra and twisted non-abelian
  Poincar\'e duality

abstract:
  We give a description of the factorization homology and $E_n$ topological
Hochschild cohomology of Thom spectra arising from $n$-fold loop maps $f: A \to
BO$, where $A = \Omega^n X$ is an $n$-fold loop space. We describe the
factorization homology $\int_M Th(f)$ as the Thom spectrum associated to a
certain map $\int _M A \to BO$. When $M$ is framed and $X$ is
$(n-1)$-connected, this spectrum is equivalent to a Thom spectrum of a virtual
bundle over the mapping space $Map_c(M,X)$; in general, this is a Thom spectrum
of a virtual bundle over a certain section space. This can be viewed as a
twisted form of the non-abelian Poincar\'e duality theorem of Segal, Salvatore,
and Lurie, which occurs when $f: A \to BO$ is nullhomotopic. This result also
generalizes the results of Blumberg-Cohen-Schlichtkrull on the topological
Hochschild homology of Thom spectra, and of Schlichtkrull on higher topological
Hochschild homology of Thom spectra. We use this to calculate the factorization
homology of some Thom spectra, including the classical cobordism spectra,
spectra arising from systems of groups, and the Eilenberg-MacLane spectra $H
\mathbb{Z}/p$, $H\mathbb{Z}_{(p)}$, and $H\mathbb{Z}$. We build upon the
description of the factorization homology of Thom spectra to study the ($n=1$
and higher) topological Hochschild cohomology of Thom spectra, which enables
calculations and a description in terms of sections of a parametrized spectrum.
If $X$ is a closed manifold, Atiyah duality for parametrized spectra allows us
to deduce a duality between $E_n$ topological Hochschild homology and $E_n$
topological Hochschild cohomology, recovering string topology operations when
$f$ is nullhomotopic. In conjunction with the higher Deligne conjecture, this
gives $E_{n+1}$ structures on a certain family of Thom spectra, which were not
previously known to be ring spectra.


title: Numerical computations on the zeros of the Euler double zeta-function II

abstract:
  We study the behavior of zero-divisors of the double zeta-function
$\zeta_2(s_1,s_2)$. In our former paper \cite{MatSho14} we studied the case
$s_1=s_2$, but in the present paper we consider the more general two variable
situation. We carry out numerical computations in order to trace the behavior
of zero-divisors. We observe that some divisors approach the points with
$s_2=0$, while other divisors approach the points which are solutions of
$\zeta(s_2)=1$.


title:
A quasi-isometric embedding into the group of Hamiltonian
  diffeomorphisms with Hofer's metric

abstract:
  We construct an embedding $\Phi$ of $[0,1]^{\infty}$ into $Ham(M, \omega)$,
the group of Hamiltonian diffeomorphisms of a suitable closed symplectic
manifold $(M, \omega)$. We then prove that $\Phi$ is in fact a quasi-isometry.
After imposing further assumptions on $(M, \omega)$, we adapt our methods to
construct a similar embedding of $\mathbb{R} \oplus [0,1]^{\infty}$ into either
$Ham(M, \omega)$ or $\widetilde{Ham}(M, \omega)$, the universal cover of
$Ham(M, \omega)$. Along the way, we prove results related to the filtered Floer
chain complexes of radially symmetric Hamiltonians. Our proofs rely heavily on
a continuity result for barcodes (as presented in the work of M. Usher and J.
Zhang) associated to filtered Floer homology viewed as a persistence module.


title: Pairing Phase Transitions of Matter under Rotation

abstract:
  The phases and properties of matter under global rotation have attracted much
interest recently. In this paper we investigate the pairing phenomena in a
system of fermions under the presence of rotation. We find that there is a
generic suppression effect on pairing states with zero angular momentum. We
demonstrate this effect with the chiral condensation and the color
superconductivity in hot dense QCD matter as explicit examples. In the case of
chiral condensation, a new phase diagram in the temperature-rotation parameter
space is found, with a nontrivial critical point.

categories: hep-ph cond-mat.quant-gas hep-th nucl-th quant-ph