title:
Packing near the tiling density and exponential bases for product
  domains

abstract:
  A set $\Omega$ in a locally compact abelian group is called spectral if
$L^2(\Omega)$ has an orthogonal basis of group characters. An important
problem, connected with the so-called Spectral Set Conjecture (saying that
$\Omega$ is spectral if and only if a collection of translates of $\Omega$ can
partition the group), is the question of whether the spectrality of a product
set $\Omega = A \times B$, in a product group, implies the spectrality of the
factors $A$ and $B$. Recently Greenfeld and Lev proved that if $I$ is an
interval and $\Omega \subseteq {\mathbb R}^d$ then the spectrality of $I \times
\Omega$ implies the spectrality of $\Omega$. We give a different proof of this
fact by first proving a result about packings of high density implying the
existence of tilings by translates of a function. This allows us to improve the
result to a wider collection of product sets than those dealt with by Greenfeld
and Lev. For instance when $A$ is a union of two intervals in ${\mathbb R}$
then we show that the spectrality of $A \times \Omega$ implies the spectrality
of both $A$ and $\Omega$.


title: Fast equilibrium switch of a micro mechanical oscillator

abstract:
  We demonstrate an accurate method to control the motion of a micromechanical
oscillator in contact with a thermal bath. The experiment is carried out on the
cantilever tip of an Atomic Force Microscope (AFM). Applying an appropriate
time dependent external force, we decrease the time necessary to reach
equilibrium by two orders of magnitude compared to the intrinsic equilibration
time. Finally, we analyze the energetic cost of such a fast equilibration, by
measuring with kBT accuracy the energy exchanges along the process.


title:
Creating and probing the Sachdev-Ye-Kitaev model with ultracold gases:
  Towards experimental studies of quantum gravity

abstract:
  We suggest that the holographic principle, combined with recent technological
advances in atomic, molecular, and optical physics, can lead to experimental
studies of quantum gravity. As a specific example, we consider the
Sachdev-Ye-Kitaev (SYK) model, which consists of spin-polarized fermions with
an all-to-all complex random two-body hopping and has been conjectured to be
dual to a certain quantum gravitational system. Achieving low-temperature
states of the SYK model is interpreted as a realization of a stringy black
hole, provided that the holographic duality is true. We introduce a variant of
the SYK model, in which the random two-body hopping is real. This model is
equivalent to the origincal SYK model in the large-$N$ limit. We show that this
model can be created in principle by confining ultracold fermionic atoms into
optical lattices and coupling two atoms with molecular states via
photo-association lasers. This development serves as an important first step
towards an experimental realization of such systems dual to quantum black
holes. We also show how to measure out-of-time-order correlation functions of
the SYK model, which allow for identifying the maximally chaotic property of
the black hole.

categories: cond-mat.quant-gas gr-qc hep-th quant-ph


title:
The Internet of Things for Aging and Independent Living: A Modeling and
  Simulation Study

abstract:
  Population aging is affecting many countries, Sweden being one of them, and
it may lead to a shortage of caregivers for elderly people in near future.
Smart interconnected devices known as the Internet of Things may help elderly
to live independently at home and avoid unnecessary hospital stay. For
instance, a carephone device enables the elderly to establish a communication
link with caregivers and ask for help when it is needed. In this paper, we
describe a simulation study of the care giving system in the V\"axj\"o
municipality in Sweden. The simulation model can be used to address various
issues, such as, determining the lack or excess of resources or long waiting
times, and study the system behavior when the number of alarms is increased.


title:
Height-dependence of spatio-temporal spectra of wall-bounded turbulence
  - LES results and model predictions

abstract:
  Wavenumber-frequency spectra of the streamwise velocity component obtained
from large-eddy simulations are presented. Following a recent paper [Wilczek et
al., J. Fluid. Mech., 769:R1, 2015] we show that the main features, a Doppler
shift and a Doppler broadening of frequencies, are captured by an advection
model based on the Tennekes-Kraichnan random-sweeping hypothesis with
additional mean flow. In this paper, we focus on the height-dependence of the
spectra within the logarithmic layer of the flow. We furthermore benchmark an
analytical model spectrum that takes the predictions of the random-sweeping
model as a starting point and find good agreement with the LES data. We also
quantify the influence of LES grid resolution on the wavenumber-frequency
spectra.


title: The Spectra of Local Minima in Spin-Glass Models

abstract:
  The spectra of spin models have been investigated in computation experiments.
For the Sherrington-Kirkpatrick and Edwards-Anderson models we have determined
the basic spectral characteristics: the average depth of a local minimum, the
spectrum width, the depth of the global minimum. The experimental data are used
to build the relations between these quantities and the model dimensionality N
and find their asymptotic values for N goes to infinity.


title: The stellar mass distribution of S$^{4}$G disk galaxies

abstract:
  We use 3.6 $\mu$m imaging from the S$^{4}$G survey to characterize the
typical stellar density profiles ($\Sigma_{\ast}$) and bars as a function of
fundamental galaxy parameters (e.g. the total stellar mass $M_{\ast}$),
providing observational constraints for galaxy simulation models to be compared
with. We rescale galaxy images to a common frame determined by the size in
physical units, by their disk scalelength, or by their bar size and
orientation. We stack the resized images to obtain statistically representative
average stellar disks and bars. For a given $M_{\ast}$ bin ($\ge
10^{9}M_{\odot}$), we find a significant difference in the stellar density
profiles of barred and non-barred systems that gives evidence for bar-induced
secular evolution of disk galaxies: (i) disks in barred galaxies show larger
scalelengths and fainter extrapolated central surface brightnesses, (ii) the
mean surface brightness profiles of barred and non-barred galaxies intersect
each other slightly beyond the mean bar length, most likely at the bar
corotation, and (iii) the central mass concentration of barred galaxies is
larger (by almost a factor 2 when $T<5$) than in their non-barred counterparts.
We also show that early- and intermediate-type spirals ($0 \le T < 5$) host
intrinsically narrower bars than the later types and S0s, whose bars are
oval-shaped. We show a clear correlation between galaxy family and bar
ellipticity.


title: Business Process Management: Saving the Planet?

abstract:
  Organisational and government concerns about environmental sustainability
(ES) are on the increase. While a significant amount of research from a wide
range of domains has addressed various ES challenges, intuitively, Business
Process Management (BPM), with its focus on process improvement and process
performance measurement, has much to offer the ES field. In this paper we aim
to understand the BPM research contribution to ES, including specific
Environmental Performance Indicators (EPI), and the BPM concepts that have been
utilized in the ES context. To this end we conduct a systematic literature
review to capture prior research focused on BPM and ES, coding the articles
according to their contribution to EPIs and other ES concepts, while also
contrasting their focus with main challenges identified in industry reports.
Our study identifies which EPIs have been addressed in prior BPM research and
highlights areas of future contribution.


title:
The Relationship between Organization Culture and Knowledge sharing
  towards Business System Success

abstract:
  Understanding the business systems success factors has been a challenging
process for both public and private organizations. Organizational culture is
measured as a critical factor promoting knowledge sharing among employees.
Based on the competing value framework (CVF), this research shows how various
dimensions of organization culture influence knowledge sharing towards business
systems success at the individual and organization level. A quantitative
approach was applied to test the relationship between organizational cultures,
knowledge sharing and business systems success in Saudi enterprise.


title:
Learning Semantically and Additively Compositional Distributional
  Representations

abstract:
  This paper connects a vector-based composition model to a formal semantics,
the Dependency-based Compositional Semantics (DCS). We show theoretical
evidence that the vector compositions in our model conform to the logic of DCS.
Experimentally, we show that vector-based composition brings a strong ability
to calculate similar phrases as similar vectors, achieving near
state-of-the-art on a wide range of phrase similarity tasks and relation
classification; meanwhile, DCS can guide building vectors for structured
queries that can be directly executed. We evaluate this utility on sentence
completion task and report a new state-of-the-art.


title: The Potential Impact of Digital Currencies on the Australian Economy

abstract:
  Crypto-currencies like Bitcoins are relatively recent phenomena on the online
Internet landscape and an emerging force in the financial sector. While not
conforming to traditional institutional practices, they are gaining increasing
acceptance as viable commercial currencies. In this conceptual paper we discuss
the potential impact of digital currency technology on the Australian economy,
including the (i) payments sector, (ii) retail sector, and (iii) banking
sector; and explore potential ways in which Australia can take advantage of
digital currency technology to establish itself as a market leader in this
field. The emergence of this new and potentially disruptive technology provides
both opportunities as well as risks. In order to support innovation and the
needs of the growing Australian digital currency industry it is important to
define digital currencies and examine the impact regulatory frameworks could
have on the further adoption and diffusion of the technology.


title: (Almost) Practical Tree Codes

abstract:
  We consider the problem of stabilizing an unstable plant driven by bounded
noise over a digital noisy communication link, a scenario at the heart of
networked control. To stabilize such a plant, one needs real-time encoding and
decoding with an error probability profile that decays exponentially with the
decoding delay. The works of Schulman and Sahai over the past two decades have
developed the notions of tree codes and anytime capacity, and provided the
theoretical framework for studying such problems. Nonetheless, there has been
little practical progress in this area due to the absence of explicit
constructions of tree codes with efficient encoding and decoding algorithms.
Recently, linear time-invariant tree codes were proposed to achieve the desired
result under maximum-likelihood decoding. In this work, we take one more step
towards practicality, by showing that these codes can be efficiently decoded
using sequential decoding algorithms, up to some loss in performance (and with
some practical complexity caveats). We supplement our theoretical results with
numerical simulations that demonstrate the effectiveness of the decoder in a
control system setting.


title: Skyrmions with attractive interactions in an ultrathin magnetic film

abstract:
  We determined the parameters of a classical spin Hamiltonian describing an Fe
monolayer on Pd(111) surface with a Pt_{1-x}Ir_{x} alloy overlayer from ab
initio calculations. While the ground state of the system is ferromagnetic for
x=0.00, it becomes a spin spiral state as Ir is intermixed into the overlayer.
Although the Dzyaloshinsky-Moriya interaction is present in the system, we will
demonstrate that the frustrated isotropic exchange interactions play a
prominent role in creating the spin spiral state, and these frustrated
couplings lead to an attractive interaction between skyrmions at short
distances. Using spin dynamics simulations, we show that under these conditions
the individual skyrmions form clusters, and that these clusters remain stable
at finite temperature.


title:
On the Benefit of Merging Suffix Array Intervals for Parallel Pattern
  Matching

abstract:
  We present parallel algorithms for exact and approximate pattern matching
with suffix arrays, using a CREW-PRAM with $p$ processors. Given a static text
of length $n$, we first show how to compute the suffix array interval of a
given pattern of length $m$ in $O(\frac{m}{p}+ \lg p + \lg\lg p\cdot\lg\lg n)$
time for $p \le m$. For approximate pattern matching with $k$ differences or
mismatches, we show how to compute all occurrences of a given pattern in
$O(\frac{m^k\sigma^k}{p}\max\left(k,\lg\lg n\right)\!+\!(1+\frac{m}{p}) \lg
p\cdot \lg\lg n + \text{occ})$ time, where $\sigma$ is the size of the alphabet
and $p \le \sigma^k m^k$. The workhorse of our algorithms is a data structure
for merging suffix array intervals quickly: Given the suffix array intervals
for two patterns $P$ and $P'$, we present a data structure for computing the
interval of $PP'$ in $O(\lg\lg n)$ sequential time, or in $O(1+\lg_p\lg n)$
parallel time. All our data structures are of size $O(n)$ bits (in addition to
the suffix array).


title: Modeling recombination processe in RE doped Up-Conversion nanocrystals

abstract:
  Up-conversion nanocrystals (UCNCs) are a new class of nonlinear optical
materials converting low energy excitation to high energy emission. Recent
advances in synthesis techniques enable a control over size, shape, emission
color purity as well as optical tuning [1]. Those UCNCs are characterized by
high surface to volume ratio allowing interesting attributes such as water
solubility and biological functionality. UCNCs usually consist of an inorganic
host that is doped with Ln^{3+} ions. The most efficient host matrix known is
the one used to test our model, namely, NaGdF_4 nanocrystals co-doped with
Er^{3+} as an acceptor/activator and Yb^{3+} as a donor/sensitizer. In this
work, we introduce the theoretical background needed to understand the nature
of ion-ion interactions occurring in these systems as well as the details of
the 4f transitions characteristic of RE-ions. In the second chapter, we present
our model through a system of rate equations corresponding to a custom energy
diagram. Then, we show our simulations producing fits of Time Resolved Photo
Luminescence (TRPL) data. Finally, we construct an improved model aiming to
encompass all the processes that seem to be involved in the luminescence of the
samples studied and we present the achievements of such approach.


title:
Point-wise mutual information-based video segmentation with high
  temporal consistency

abstract:
  In this paper, we tackle the problem of temporally consistent boundary
detection and hierarchical segmentation in videos. While finding the best
high-level reasoning of region assignments in videos is the focus of much
recent research, temporal consistency in boundary detection has so far only
rarely been tackled. We argue that temporally consistent boundaries are a key
component to temporally consistent region assignment. The proposed method is
based on the point-wise mutual information (PMI) of spatio-temporal voxels.
Temporal consistency is established by an evaluation of PMI-based point
affinities in the spectral domain over space and time. Thus, the proposed
method is independent of any optical flow computation or previously learned
motion models. The proposed low-level video segmentation method outperforms the
learning-based state of the art in terms of standard region metrics.


title: An efficient mathematically correct scale free CORDIC

abstract:
  In order to approximate transandental functions, several algorithms were
proposed.Historically, polynomial interpolation, infinite series, $\cdots$ and
other$+,\times, -$ and $/$ based algorithms were studied for this purpose.The
CORDIC (COordinate Rotation DIgital Computer)introduced by Jack E. Volder in
1959, and generalized by J. S. Walther a few years later, is a hardware based
algorithmfor the approximation of trigonometric, hyperbolic andlogarithmic
functions.As a consequence, CORDIC is used for applications indiverse areas
such as signal and image processing.For these reasons, several modified
versions were proposed.In this article, we present anoverview of the CORDIC
algorithm for the computation of the circular functions, essentially the
scaling free version,and we will give a substential improvement to the commonly
used one.


title:
A method to decrease the harmonic distortion in Mn-Zn ferrite/PZT and
  Ni-Zn ferrite/PZT layered composite rings exhibiting high magnetoelectric
  effects

abstract:
  We have investigated the magnetoelectric (ME) effect in layered composite
rings subjected to circumferential AC magnetic fields and DC magnetic fields in
radial, axial or circumferential directions. Bilayer samples were obtained
combining different grades of commercial Mn-Zn ferrites or Ni-Zn ferrites with
commercial lead zirconate titanate (PZT). Mn-Zn ferrites with low
magnetostriction saturation () and low magneto-crystalline anisotropy constants
show high ME capabilities when associated with PZT in ring structures. In
certain conditions, these ME effects are higher than those obtained with
Terfenol-D/PZT composites in the same layered ring structure. Magnetostrictive
and mechanical characterizations have given results that explain these high ME
performances. Nevertheless, Mn-Zn ferrite/PZT composites exhibit voltages
responses with low linearity especially at high signal level. Based on the
particular structure of the ME device, a method to decrease the nonlinear
harmonic distortion of the ME voltages is proposed. Harmonic distortion
analysis of ME voltages measured in different configurations allows us to
explain the phenomenon.


title: Spectral measure at zero for self-similar tilings

abstract:
  The goal of this paper is to study the action of the group of translations
over self-similar tilings in the euclidian space $\mathbb{R}^d$. It
investigates the behaviour near zero for spectral measures for such dynamical
systems. Namely the paper gives a H\"older asymptotic expansion near zero for
these spectral measures. It is a generalization to higher dimension of a result
by Bufetov and Solomyak who studied self similar-suspension flows for
substitutions. The study of such asymptotics mostly involves the understanding
of the deviations of some ergodic averages.


title:
Experimental demonstration of graphene plasmons working close to the
  near-infrared window

abstract:
  Due to strong mode-confinement, long propagation-distance, and unique
tunability, graphene plasmons have been widely explored in the mid-infrared and
terahertz windows. However, it remains a big challenge to push graphene
plasmons to shorter wavelengths in order to integrate graphene plasmon concepts
with existing mature technologies in the near-infrared region. We investigate
localized graphene plasmons supported by graphene nanodisks and experimentally
demonstrated graphene plasmon working at 2 {\mu}m with the aid of a fully
scalable block copolymer self-assembly method. Our results show a promising way
to promote graphene plasmons for both fundamental studies and potential
applications in the near-infrared window.


title:
Solvability of a Lie algebra of vector fields implies their
  integrability by quadratures

abstract:
  We present a substantial generalisation of a classical result by Lie on
integrability by quadratures. Namely, we prove that all vector fields in a
finite-dimensional transitive and solvable Lie algebra of vector fields on a
manifold can be integrated by quadratures.


title:
Magnetoelectric effect in layered ferrite/PZT composites. Study of the
  demagnetizing effect on the magnetoelectric behavior

abstract:
  We report the use of high magnetomechanical coupling ferrites in
magnetoelectric (ME) layered composites. Bilayer samples combining $(Ni_{0.973}
Co_{0.027})_{1-x} Zn_x Fe_2 O_4$ ferrites ($x = 0-0.5$) synthesized by non
conventional reactive Spark Plasma Sintering and commercial lead zirconate
titanate (PZT) were characterized in term of ME voltage coefficients measured
at sub-resonant frequency. Strong ME effects are obtained and we show that an
annealing at 1000$^\circ$C and a quenching in air improve the piezomagnetic
behavior of Zn-rich compositions. A theoretical model that predicts the ME
behavior was developed, focusing our work on the demagnetizing effects in the
transversal mode as well as the longitudinal mode. The model shows that: (i)
high ME coefficients are obtained when ferrites with high magnetomechanical
coupling are used in bilayer ME composites, (ii) the ME behavior in transversal
and longitudinal modes is quite similar, and differences in the shapes of the
ME curves are mainly due the demagnetizing effects, (iii) in the transversal
mode, the magnetic field penetration depends on the ferrite layer thickness and
the ME coefficient is affected accordingly. The two later points are confirmed
by measurements on ME samples and calculations. Performances of the ME
composites made with high magnetomechanical coupling ferrites are compared to
those obtained using Terfenol-D materials in the same conditions of size,
shape, and volume ratio. It appears that a ferrite with an optimized
composition has performances comparable to those obtained with Terfenol-D
material. Nevertheless, the fabrication processes of ferrites are quite
simpler. Finally, a ferrite/PZT based ME composite was used as a current
sensor.


title: Reversible homogeneous Finsler metrics with positive flag curvature

abstract:
  We classify homogeneous reversible Finsler metrics with positive Flag
curvature. We show that if G/H admits a G invariant reversible Finsler metric
with positive Flag curvature, then up to a few low dimensional spaces, it also
admits a G invariant Riemannian metric with positive sectional curvature. For
the exceptions, we do not know if they admit homogeneous Finsler metrics with
positive Flag curvature.


title: Unfolded equations for massive higher spin supermultiplets in AdS_3

abstract:
  In this paper we give an explicit construction of unfolded equations for
massive higher spin supermultiplets of the minimal (1,0) supersymmetry in AdS_3
space. For that purpose we use an unfolded formulation for massive bosonic and
fermionic higher spins and find supertransformations leaving appropriate set of
unfolded equations invariant. We provide two general supermultiplets (s, s+1/2)
and (s, s-1/2) with arbitrary integer s, as well as a number of lower spin
examples.


title:
Quasinormal extensions of subnormal operator-weighted composition
  operators in $\ell^2$-spaces

abstract:
  We prove the subnormality of an operator-weighted composition operator whose
symbol is a transformation of a discrete measure space and weights are
multiplication operators in $L^2$-spaces under the assumption of existence of a
family of probability measures whose Radon-Nikodym derivatives behave regular
along the trajectories of the symbol. We build the quasinormal extension which
is a weighted composition operator induced by the same symbol. We give
auxiliary results concerning commutativity of operator-weighted composition
operators with multiplication operators.


title: On the Kuznetsov Trace Formula for $\mathrm{PGL}_2(\mathbb{C})$

abstract:
  In this note, using a representation theoretic method of Cogdell and
Piatetski-Shapiro, we prove the Kuznetsov trace formula for an arbitrary
discrete group $\Gamma$ in $\mathrm{PGL}_2(\mathbb{C})$ that is cofinite but
not cocompact. An essential ingredient is a kernel formula, recently proved by
the author, on Bessel functions for $\mathrm{PGL}_2(\mathbb{C})$. This approach
avoids the difficult analysis in the existing method due to Bruggeman and
Motohashi.


title: Shared Secret Places: Social Media and Affordances

abstract:
  The Social Media application Strava is used by exercisers to track running
and cycling activities. Strava is carried with the exerciser and displays
trophies and leaderboards to reward competitive performance. We were prompted
by an auto-ethnographic account of Strava use to examine the way in which a
particular stretch of running track around a lake showed up differently to the
runner once Strava was integrated into their running practice. We look to
Gibsons relational notion of affordances and niches to understand this change
in direct perception. We propose that these concepts have potential in helping
us to research and understand the ways in which groups of Social Media users
share and construct a similar experience of place in a way that is largely
invisible to non-users. We consider some of the preliminary implications of
this differentiated use of place and demonstrate the way in which a relational
view of affordances helps us to make sense of this phenomenon.


title: Neighborhood-Preserving Translations on Graphs

abstract:
  In many domains (e.g. Internet of Things, neuroimaging) signals are naturally
supported on graphs. These graphs usually convey information on similarity
between the values taken by the signal at the corresponding vertices. An
interest of using graphs is that it allows to define ad hoc operators to
perform signal processing. Among them, ones of paramount importance in many
tasks are translations. In this paper we are interested in defining
translations on graphs using a few simple properties. Namely we propose to
define translations as functions from vertices to adjacent ones, that preserve
neighborhood properties of the graph. We show that our definitions, contrary to
other works on the subject, match usual translations on grid graphs.


title: A Framework for Techniques for Information Technology Enabled Innovation

abstract:
  Australia is seen as lagging in the innovation that is needed for corporate
success and national productivity gains. There is an apparent lack of
consistent and integrated advice to managers on how to undertake innovation.
Thus, this study aims to develop and investigate a framework that relates
innovation practices to the type of innovation outcome, in the context of
Information Technology (IT) enabled innovations. An Innovation Practice
Framework was developed based on the Knowledge-Innovation Matrix (KIM) proposed
by Gregor and Hevner (2015). Eleven commonly used innovation techniques
(practices) were identified and placed in one or more of the quadrants:
invention, advancement, exaptation and exploitation. Interviews were conducted
with key informants in nine organisations in the Australian Capital Territory.
Results showed that the least used techniques were skunk works and
crowdsourcing. The most used techniques were traditional market research,
brainstorming and design thinking. The Innovation Practice Framework was given
some support, with genius grants being related to invention outcomes, design
thinking with exaptation, traditional R&D with advancement and managerial
scanning with exploitation. The study contributes theoretically with the new
Innovation Practice Framework and has the potential to be useful to managers in
showing how benefits can be gained from a range of innovation practices.
Further work is in progress.


title: Viscosity in a Lepton-Photon Universe

abstract:
  We look at viscosity production in a universe consisting purely of leptons
and photons. This is quite close to what the Universe actually look like when
the temperature was between $10^{10}$ K and $10^{12}$ K ($1$ -- $100$ MeV). By
taking the strong force and the hadronic particles out of the equation, we can
examine how the viscous forces behave with all the 12 leptons present. By this
we study how shear- and (more interestingly) bulk viscosity is affected during
periods with particle annihilation. We use the theory given by Hoogeveen et.
al. from 1986, replicate their 9-particle results and expanded it to include
the muon and tau particles as well. This will impact the bulk viscosity
immensely for high temperatures. We will show that during the beginning of the
lepton era, when the temperature is around 100 MeV, the bulk viscosity will be
roughly 100 million times larger with muons included in the model compared to a
model without.


title: New Methods for Top-Quark Mass Measurements at the LHC

abstract:
  Several recent new measurements of the top-quark mass that use alternative
observables and reconstruction techniques are presented, performed by the ATLAS
and CMS collaborations at the CERN LHC. Alternative observables can help
provide insight by presenting different systematic sensitivities and by
constraining prevailing systematic uncertainties of standard measurements, such
as jet energy calibrations. Furthermore, the top-quark mass is extracted from
theoretically well-defined observables, such as the inclusive production cross
section for top quark pairs. Finally, the mass is measured in event topologies
dominated by electroweak-mediated single top production by both experiments.
The results of different techniques and production modes are found to be
consistent with what is obtained in standard measurements.


title:
Virtualising Process Assessments to Facilitate Continual Service
  Improvement in IT Service Management

abstract:
  The IT Service Management (ITSM) industry has defined processes as best
practices in the widely-accepted IT Infrastructure Library (ITIL) framework.
However, studies on the measurement of ITSM process improvement are scant. Our
research addressed the dual problems of the lack of transparency and the need
for efficiency in ITSM process assessment. Using the Design Science Research
methodology, we developed a Software-mediated Process Assessment (SMPA)
approach that enables assessment of ITSM processes. The SMPA approach includes
process selection; online survey to collect assessment data; measurement of
process capability; and reporting of process improvement recommendations. We
implemented a decision support system (DSS) to automate the SMPA approach and
evaluated it at two IT service providers. The evaluations indicated that the
SMPA approach supports decision-making on process improvements. The findings
provided design knowledge of virtualisation in ITSM process assessment and how
this may facilitate continual service improvement.


title:
Effect of quantum noise on deterministic joint remote state preparation
  of a qubit state via a GHZ channel

abstract:
  Quantum secure communication brings a new direction for information security.
As an important component of quantum secure communication, deterministic joint
remote state preparation (DJRSP) could securely transmit a quantum state with
100\% success probability. In this paper, we study how the efficiency of DJRSP
is affected when qubits involved in the protocol are subjected to noise or
decoherence. Taking a GHZ based DJRSP scheme as an example, we study all types
of noise usually encountered in real-world implementations of quantum
communication protocols, i.e., the bit-flip, phase-flip (phase-damping),
depolarizing, and amplitude-damping noise. Our study shows that the fidelity of
the output state depends on the phase factor, the amplitude factor and the
noise parameter in the bit-flip noise, while the fidelity only depends on the
amplitude factor and the noise parameter in the other three types of noise. And
the receiver will get different output states depending on the first preparer's
measurement result in the amplitude-damping noise. Our results will be helpful
for improving quantum secure communication in real implementation.


title:
Exploring Implicit Human Responses to Robot Mistakes in a Learning from
  Demonstration Task

abstract:
  As robots enter human environments, they will be expected to accomplish a
tremendous range of tasks. It is not feasible for robot designers to
pre-program these behaviors or know them in advance, so one way to address this
is through end-user programming, such as via learning from demonstration (LfD).
While significant work has been done on the mechanics of enabling robot
learning from human teachers, one unexplored aspect is enabling mutual feedback
between both the human teacher and robot during the learning process, i.e.,
implicit learning. In this paper, we explore one aspect of this mutual
understanding, grounding sequences, where both a human and robot provide
non-verbal feedback to signify their mutual understanding during interaction.
We conducted a study where people taught an autonomous humanoid robot a dance,
and performed gesture analysis to measure people's responses to the robot
during correct and incorrect demonstrations.


title:
Exploring the Use of Enterprise 2.0 and Its Impact on Social Capital
  within a Large Organisation

abstract:
  Despite the rampant adoption of Enterprise 2.0, there is lack of empirical
evidence of how Enterprise 2.0 is aptly supporting the business objectives.
Social capital theory will be used as a theoretical lens to understand the
impact and implications of individual use of Enterprise 2.0. To ascertain the
impact from the use of Enterprise 2.0 on the various dimensions of social
capital, a single in-depth qualitative case study was conducted with a large
professional services organisation. The findings unfold the different areas of
impacts based on actual individual use and experience. The research concludes
with a framework delineating the intertwined relationship between each social
capital dimensions.


title: Lie algebroid cohomology as a derived functor

abstract:
  We show that the hypercohomology of the Chevalley-Eilenberg-de Rham complex
of a Lie algebroid L over a scheme with coefficients in an L-module can be
expressed as a derived functor. We use this fact to study a Hochschild-Serre
type spectral sequence attached to an extension of Lie algebroids.


title:
Bring Your Own Devices Classroom: Issues of Digital Divides in Teaching
  and Learning Contexts

abstract:
  Technology mediated learning provide potentially valuable resources for
learners' academic and social development. However, according to recent
researches, as the adoption stages of ICTs advance there arise further levels
of digital divides in terms of equity of information literacy and learning
outcomes. For the last three years we have been working with the first
secondary school in New Zealand to introduce a Bring Your Own Device (BYOD)
policy. Our research has included a number of methods, including surveys,
interviews and classroom observations. In this paper we present the findings
from the investigation into BYOD project, which gave us insights into the
digital divide issues in the context of technology mediated learning.


title: Monotonicity formulas in potential theory

abstract:
  Using the electrostatic potential $u$ due to a uniformly charged body
$\Omega\subset\mathbb R^n$, $n\geq 3$, we introduce a family of monotone
quantities associated with the level set flow of $u$. The derived monotonicity
formulas are exploited to deduce a new quantitative version of the classical
Willmore inequality.


title: A new characterisation of groups amongst monoids

abstract:
  We prove that a monoid $M$ is a group if and only if, in the category of
monoids, all points over $M$ are strong. This sharpens and greatly simplifies a
result of Montoli, Rodelo and Van der Linden which characterises groups amongst
monoids as the protomodular objects.


title:
Strong optomechanical coupling in a slotted photonic crystal nanobeam
  cavity with an ultrahigh quality factor-to-mode volume ratio

abstract:
  We describe the design, fabrication, and characterization of a
one-dimensional silicon photonic crystal cavity in which a central slot is used
to enhance the overlap between highly localized optical and mechanical modes.
The optical mode has an extremely small mode volume of 0.017
$(\lambda_{vac}/n)^3$, and an optomechanical vacuum coupling rate of 310 kHz is
measured. With optical quality factors up to $1.2 \cdot 10^5$, fabricated
devices are in the resolved-sideband regime. The electric field has its maximum
at the slot wall and couples to the in-plane breathing motion of the slot. The
optomechanical coupling is thus dominated by the moving-boundary effect, which
we simulate to be six times greater than the photoelastic effect, in contrast
to most structures, where the photoelastic effect is often the primary coupling
mechanism.


title: Convolutional Neural Fabrics

abstract:
  Despite the success of CNNs, selecting the optimal architecture for a given
task remains an open problem. Instead of aiming to select a single optimal
architecture, we propose a "fabric" that embeds an exponentially large number
of architectures. The fabric consists of a 3D trellis that connects response
maps at different layers, scales, and channels with a sparse homogeneous local
connectivity pattern. The only hyper-parameters of a fabric are the number of
channels and layers. While individual architectures can be recovered as paths,
the fabric can in addition ensemble all embedded architectures together,
sharing their weights where their paths overlap. Parameters can be learned
using standard methods based on back-propagation, at a cost that scales
linearly in the fabric size. We present benchmark results competitive with the
state of the art for image classification on MNIST and CIFAR10, and for
semantic segmentation on the Part Labels dataset.


title:
A DSS framework for maintaining relevant features of the Small Business
  B2C Websites

abstract:
  Managers are heavily engaged in strategic decision-making for businesses,
particularly in a changing environment. One of the most important decisions for
online small businesses, as part of their strategic planning, is selecting
relevant features on their websites, both to attract and interact with
consumers. However, only a few Australian small businesses use strategic tools
for selecting their website features. As a result, businesses lose potential
domestic sales in the business-to-consumer (B2C) sector. The aim of this study
is to determine the relationship between factors that influence consumers'
online purchasing, and owner/manager strategic decisions in selecting relevant
features for websites. Results from employing qualitative case studies with
small business owner/managers, and a content analysis of website features,
inform the design of a Decision Support Systems (DSS) framework. This may
assist owner/managers' strategic decisions to implement competitive features on
B2C websites that ultimately attract more consumers.


title:
Engineering Double-Well Potentials with Variable-Width Annular Josephson
  Tunnel Junctions

abstract:
  Long Josephson tunnel junction are non-linear transmission lines that allow
propagation of current vortices (fluxons) and electromagnetic waves and are
used in various applications within superconductive electronics. Recently, the
Josephson vortex has been proposed as a new superconducting qubit. We describe
a simple method to create a double-well potential for an individual fluxon
trapped in a long elliptic annular Josephson tunnel junction characterized by
an intrinsic non-uniform width. The distance between the potential wells and
the height of the inter-well potential barrier are controlled by the strength
of an in-plane magnetic field. The manipulation of the vortex states can be
achieved by applying a proper current ramp across the junction. The read-out of
the state is accomplished by measuring the vortex depinning current in a small
magnetic field. An accurate one-dimensional sine-Gordon model for this strongly
non-linear system is presented, from which we calculate the position-dependent
fluxon rest-mass, its Hamiltonian density and the corresponding trajectories in
the phase space. We examine the dependence of the potential properties on the
annulus eccentricity and its electrical parameters and address the requirements
for observing quantum-mechanical effects, as discrete energy levels and
tunneling, in this two-state system.


title: Atomic Ordering in Cubic Bismuth Telluride Alloy Phases at High Pressure

abstract:
  Pressure-induced transitions from ordered intermetallic phases to
substitutional alloys to semi-ordered phases were studied in a series of
bismuth tellurides. Using angle-dispersive x-ray diffraction, the compounds
Bi4Te5, BiTe, and Bi2Te were observed to form alloys with the disordered
body-centered cubic (bcc) crystal structure upon compression to above 14--19
GPa at room temperature. The BiTe and Bi2Te alloys and the previously
discovered high-pressure alloys of Bi2Te3 and Bi4Te3 were all found to show
atomic ordering after gentle annealing at very moderate temperatures of
~100{\deg}C. Upon annealing, BiTe transforms from the bcc to the B2 (CsCl)
crystal structure type, and the other phases adopt semi-disordered variants
thereof, featuring substitutional disorder on one of the two crystallographic
sites. The transition pressures and atomic volumes of the alloy phases show
systematic variations across the Bi_mTe_n series including the end members Bi
and Te. First-principles calculations were performed to characterize the
electronic structure and chemical bonding properties of B2-type BiTe and to
identify the driving forces of the ordering transition. The calculated Fermi
surface of B2-type BiTe has an intricate structure and is predicted to undergo
three topological changes between 20 and 60 GPa.


title: Remarkable analytic relations among greybody parameters

abstract:
  In this paper we derive and discuss several implications of the analytic form
of a modified blackbody, also called greybody, which is widely used in
Astrophysics, and in particular in the study of star formation in the
far-infrared/sub-millimeter domain. The research in this area has been greatly
improved thanks to recent observations taken with the Herschel satellite, so
that it became important to clarify the sense of the greybody approximation, to
suggest possible further uses, and to delimi its intervals of validity. First,
we discuss the position of the greybody peak, making difference between the
optically thin and thick regimes. Second, we analyze the behavior of bolometric
quantities as a function of the different greybody parameters. The ratio
between the bolometric luminosity and the mass of a source, the ratio between
the so-called "sub-millimeter luminosity" and the bolometric one, and the
bolometric temperature are observables used to characterize the evolutionary
stage of a source, and it is of primary importance to have analytic equations
describing the dependence of such quantities on the greybody parameters. Here
we discuss all these aspects, providing analytic relations, illustrating
particular cases and providing graphical examples. Some equations reported here
are well-known in Astrophysics, but are often spread over different
publications. Some of them, instead, are brand new and represent a novelty in
Astrophysics literature. Finally we indicate an alternative way to obtain,
under some conditions, the greybody temperature and dust emissivity directly
from an observing spectral energy distribution, avoiding a best-fit procedure.


title:
Opportunities and challenges of mobile learning for promoting
  mathematical literacy

abstract:
  Mathematical literacy plays an important role in supporting individuals to
fulfil their professional roles in modern society. The affordances of mobile
technologies as well as the emergence of new theories in mobile learning have
the potential to promote mathematical literacy. However, implementation of
mobile learning in Indonesian society faces challenges related to perceived
ethical and learning issues in curriculum-based educational settings. This
study aims to investigate the preparedness of teachers in integrating
mathematics subject content with mobile technologies, especially in promoting
mathematical literacy. An exploratory study has been conducted using mixed
methods by performing questionnaire survey and semi-structured interviews to
understand teacher's knowledge towards mathematical literacy and identifying
opportunities and challenges of mobile learning within instruction. Findings
indicate that teachers mostly do not know about mathematical literacy,
indicating that the concept of mathematical literacy needs to be promoted.
Further, most schools prohibit the use of mobile devices in classrooms as they
are wary of inappropriate use of mobile devices which may harm students' mental
health and distract them from learning. Study finds this to be the most common
cause for teachers' reluctance in using mobile learning.


title:
The Invariance and Conservation Laws of fourth-order Difference
  Equations

abstract:
  We consider difference equations of order four and determine the one
parameter Lie group of transformations (Lie symmetries) that leave them
invariant. We introduce a technique for finding their first integrals and
discuss the association between the symmetries and first integrals as well as
the notion of multipliers (related to conservation laws) for difference
equations.


title:
Examining the social aspects of Enterprise Architecture Implementation:
  A Morphogenetic Approach

abstract:
  This paper argues that existing research in Enterprise Architecture (EA)
tends to emphasise the technical aspects of implementation and neglects the
role of 'people'. The paper uses Archer's Morphogenetic Approach (MA) to
elaborate the social context of EA. This approach examines the relationships
between agency, structure and culture to understand how stakeholders affect and
are affected by EA implementation. A university just commencing an EA program
is used as a case example. The case example describes the challenging
university environment and provides an illustration of the important
situational logics that direct agency action within the complex social context
of a university.


title:
Open data adoption in Australian government agencies: an exploratory
  study

abstract:
  Australia is among the leading countries that envisaged releasing
unclassified public data under open license and reusable format with no further
restriction on re/use. But, according to the Australian Information
Commissioner John McMillan, Australia's progress on open data is 'patchy' and
'transitional'. He also evidenced that although a few agencies are proactive
and have embraced the movements quite seriously, still there are "many
obstacles that worked against effort to make government information and data
discoverable and usable" (Hilvert 2013). Despondently, there is little
empirical evidence that could explain what makes public departments not to
release public data. Driven by the nature of the research, this study conducted
an exploratory field study in Australia by interviewing eleven employees from
six different government agencies. Applying content analysis technique, this
study identifies six important antecedents to adoption of open data in public
organisations, and proposes future research to test their relationships. As the
main theoretical contribution, this study extends organisational behaviour
toward technology diffusion. The findings of this study incite policymakers and
managers to think about and prepare future strategies on open data
developments.


title:
Interstellar medium structure and the slope of the radio $\Sigma-D$
  relation of supernova remnants

abstract:
  We analyze the influence of fractal structure of the interstellar matter
(ISM) density on the parameter values for the radio surface brightness to
diameter ($\Sigma-D$) relation for supernovae remnants (SNRs). We model a dense
ISM as a molecular cloud with fractal density structure. SNRs are modelled as
spheres of different radius scattered in the modelled ISM. The surface
brightness of the SNRs is calculated from the simple relation $\Sigma \propto
\rho^{0.5}D^{-3.5}$ and also from the parametrized more general form $\Sigma
\propto \rho^{\eta}D^{-\beta_0}$. Our results demonstrate that empirical
$\Sigma-D$ slopes that are steeper than the ones derived from theory, might be
partly explained with the fractal structure of the ambient medium into which
SNRs expand. The slope of the $\Sigma-D$ relation steepens if the density of
the regions where SNRs are formed is higher. The simple geometrical effects
combined with the fractal structure of the ISM can contribute to a steeper
empirical $\Sigma-D$ slopes, especially for older remnants, and this is more
pronounced if $\Sigma$ has a stronger dependence on ambient density.


title:
Why customers participate in social commerce activities? - A laddering
  analysis

abstract:
  A new phenomenon emerging within virtual communities is a blurring between
the social and commercial activities and motivations of participants. This
paper explores motivations for participating in social commerce at a
micro-business level between members of a virtual community of Malay lifestyle
bloggers. The selected community was observed in order to understand the
community and 21 participants were interviewed. We used laddering techniques to
explore community attributes, the perceived consequences, and their links to
the values of participants. We found that virtual community relationship was
the main influential factor, and virtual community relationship contributed to
the sense of social support as well as customers' trust in social commerce.


title: The Development Strategy of IT Capability: A Contingency Perspective

abstract:
  This study proposes a conceptual model to link IT capabilities, industry
types, and value implications. We attempt to use a contingency analysis to
theorize that which types of IT capabilities (e.g., externally-focused,
internally-focused, and aggregate IT capability) should a firm develop and then
what benefits (e.g., firm value and firm performance) it will gain according to
its industry's value creation logic (e.g., value chain-based, value shop-based,
and value network-based industry). The empirical findings show that a value
network-based firm should develop externally-focused IT capabilities to create
its firm value and a value chain-based firm should develop aggregate IT
capabilities to improve its firm performance and create its firm value.


title:
Optimizing the $\theta_{23}$ octant search in long baseline neutrino
  experiments

abstract:
  We study the possibility of determining the octant of the neutrino mixing
angle $\theta_{23}$, that is, whether $\theta_{23}> 45^\circ$ or
$\theta_{23}<45^\circ$, in long baseline neutrino experiments. Here we
numerically derived the sensitivity limits within which these experiments can
determine, by measuring the probability of the $\nu_{\mu}\to \nu_{e}$
transitions, the octant of $\theta_{23}$ with a $5\sigma$ certainty. The
interference of the CP violation angle $\delta$ with these limits, as well as
the effects of the baseline length and the run-time ratio of neutrino and
antineutrino modes of the beam have been analyzed.


title:
Assessment Issues in Mathematics: Design Science Approach for developing
  an Expert-System Based Solution

abstract:
  Information and communication technology (ICT) tools are ineffective when
assessing solutions of questions with more than one step. ICT tools assessing
these types of questions are paralleled to solving complex problems. This
conceptual paper describes the method that will be adopted to create rule based
expert system (ES) prototype implementing method marking concept (MMC) in
assessing multi-step questions (MSQ) solutions. Pragmatist views and mixed
methods will be used to conduct document analysis using undergraduate students'
solutions to past examination papers and related findings from previous
research. Design science research paradigm and ES development phases will be
used to design, construct and evaluate an artifact based on ES. The expected
functioning ES artifact will enhance the authenticity of assessment, because
evaluation of solution strategies in MSQ solution reveals how much the
comprehension of the domain under evaluation is shown. The artifact and the
conceptual framework can be applied to a similar domain with modifications or
as it is.


title: Connectedness of spheres in Cayley graphs

abstract:
  We introduce the notion of connection thickness of spheres in a Cayley graph,
related to dead-ends and their retreat depth. It was well-known that connection
thickness is bounded for finitely presented one-ended groups. We compute that
for natural generating sets of lamplighter groups on a line or on a tree,
connection thickness is linear or logarithmic respectively. We show that it
depends strongly on the generating set. We give an example where the metric
induced at the (finite) thickness of connection gives diameter of order $n^2$
to the sphere of radius $n$. We also discuss the rarity of dead-ends and the
relationships of connection thickness with cut sets in percolation theory and
with almost-convexity. Finally, we present a list of open questions about
spheres in Cayley graphs.


title: Constructing a Traditional Chinese Medicine Data Warehouse Application

abstract:
  The explosive growth in the development of Traditional Chinese Medicine (TCM)
has resulted in the continued increase in clinical and research data. The lack
of standardised terminology, flaws in data quality planning and management of
TCM informatics are preventing clinical decision-making, drug discovery and
education. This paper argues that the introduction of data warehousing
technologies to enhance the effectiveness and durability in TCM is paramount.
To showcase the role of data warehousing in the improvement of TCM, this paper
presents a practical model for data warehousing with detailed explanation,
which is based on the structured electronic records, for TCM clinical
researches and medical knowledge discovery.


title:
Using Design Science to build a Watermark System for Righful Ownership
  Protection in the Cloud

abstract:
  Cloud computing opportunities have presented service options for users that
are both economical and flexible to use requirements. However, the risk
analysis for the user identifies vulnerabilities for intellectual property
ownership and vulnerabilities for the identification of rightful property
owners when cloud services are used. It is common for image owners to embed
watermarks and other security mechanisms into their property so that the
rightful ownership may be identified. In this paper we present a design that
overcomes many of the current limitations in cloud watermarking uses and
propose a schema that places responsibility on the cloud provider to have a
robust information protection program. Such a design solution lays out an
information security architecture that enhances utility for cloud services and
gives better options for users to securely place properties in the cloud. The
Design Science methodology is used to build the artefact.


title:
Exploring Practitioner Perspectives of Sourcing Risks: Towards the
  Development of an Integrated Risk and Control Framework

abstract:
  Outsourcing of information and communication technologies (ICT) and related
services is an established and growing industry. Recent trends, such as the
move toward multi-sourcing have increased the complexity and risk of these
outsourcing arrangements. There is a critical research need to identify the
risks faced by both the organisations that outsource ICT and the vendors that
provide it in this changing landscape. To address growing concerns regarding
the best way to deal with risk and control in this environment, our research
focuses on establishing a Sourcing Risk and Control Framework to assist
organisations identify these risks and develop effective mitigation strategies.
In this paper we report on the first stage of our research that sought to
document how sourcing risk is represented and considered in practice. To date,
limited empirical research has been conducted in an Australian context. Using a
series of workshops involving client and vendor representatives, we identified
a broad range of risks and developed a cohesive categorisation scheme that
incorporates functional and multi-stakeholder perspectives.


title:
Designing an ELearning Portal for Developing Countries: An Action Design
  Approach

abstract:
  This paper presents the first phase of a study on using course design,
including current eLearning and social trends, to overcome challenges in
eLearning within developing countries, particularly for
vocational/non-mainstream training. The paper outlines the research and
development of an ICT artefact using the Action Design Research method. The
artefact will later be deployed and evaluated. The paper discusses the previous
research that has categorised challenges in eLearning in developing countries
and explores how these can be overcome through course and element design.
Course design includes training development, platform selection and platform
hosting, particularly in the context of developing countries. Element design
looks at the creation of content that should be available, practical and viable
to both the user and developer through the exploitation of current eLearning
and social trends. The paper concludes with the concept of the ICT artefact
that has been designed for phase two of the study.


title: SOA Governance - Road into Maturity

abstract:
  There is a general consensus that SOA benefits could be reached but it is
unclear how to achieve this. Research shows that the problems with SOA
governance in practice are among the major reasons of SOA failures. Based on a
literature review, this study first proposes a list of SOA aspects to be
considered when implementing SOA governance. By adopting an interpretive
research methodology based on interviews, this research paper makes two
contributions: it addresses the practical matters that are major concerns for
organisations to achieve a higher maturity level with their SOA, and it reveals
the importance of the key SOA aspects in building strong governance and
consequently reaching a higher maturity level. The expected result should
deliver a theoretical contribution to SOA maturity in relation to SOA
governance; it could provide organisations with new awareness in assessing
their level of maturity and provide recommendations.


title:
Existence and Concentration Solutions for a class of elliptic PDEs
  involving $p$-biharmonic Operator

abstract:
  In this paper, we propose an existence result pertaining to a nontrivial
solution to the problem \begin{align*} \Bigg\{\begin{split} & \Delta^2_p u
-\Delta_p u + \lambda V(x)|u|^{p-2}u = f(x,u)\,,\,x\in \mathbb{R}^N, & u \in
W^{2,p}(\mathbb{R}^N), \end{split} \end{align*} where $\lambda>0$, $p>1, N>2p$
and $V\in C(\mathbb{R}^N, \mathbb{R}^+)$, $f\in C(\mathbb{R}^N \times
\mathbb{R},\mathbb{R})$ with certain properties. We also investigate the
concentration of solutions to the problem on the set $V^{-1}(0)$ as $\lambda
\rightarrow \infty$.


title:
A Multiphase Shape Optimization Problem for Eigenvalues: Qualitative
  Study and Numerical Results

abstract:
  We consider the multiphase shape optimization problem
$$\min\Big\{\sum_{i=1}^h\lambda_1(\Omega_i)+\alpha|\Omega_i|:\ \Omega_i\
\hbox{open},\ \Omega_i\subset D,\ \Omega_i\cap\Omega_j=\emptyset\Big\},$$ where
$\alpha>0$ is a given constant and $ D\subset\Bbb{R}^2$ is a bounded open set
with Lipschitz boundary. We give some new results concerning the qualitative
properties of the optimal sets and the regularity of the corresponding
eigenfunctions. We also provide numerical results for the optimal partitions.


title: DefExt: A Semi Supervised Definition Extraction Tool

abstract:
  We present DefExt, an easy to use semi supervised Definition Extraction Tool.
DefExt is designed to extract from a target corpus those textual fragments
where a term is explicitly mentioned together with its core features, i.e. its
definition. It works on the back of a Conditional Random Fields based
sequential labeling algorithm and a bootstrapping approach. Bootstrapping
enables the model to gradually become more aware of the idiosyncrasies of the
target corpus. In this paper we describe the main components of the toolkit as
well as experimental results stemming from both automatic and manual
evaluation. We release DefExt as open source along with the necessary files to
run it in any Unix machine. We also provide access to training and test data
for immediate use.


title: The Critical Current of Point Symmetric Josephson Tunnel Junctions

abstract:
  The physics of Josephson tunnel junctions drastically depends on their
geometrical configurations. The shape of the junction determines the specific
form of the magnetic-field dependence of the its Josephson current. Here we
address the magnetic diffraction patterns of specially shaped planar Josephson
tunnel junctions in the presence of an in-plane magnetic field of arbitrary
orientations. We focus on a wide ensemble of junctions whose shape is invariant
under point reflection. We analyze the implications of this type of isometry
and derive the threshold curves of junctions whose shape is the union or the
relative complement of two point symmetric plane figures.


title: On rational R-matrices with adjoint SU(n) symmetry

abstract:
  Using the representation theory of Yangians we construct the rational
R-matrix which takes values in the adjoint representation of SU(n). From this
we derive an integrable SU(n) spin chain with lattice spins transforming under
the adjoint representation. However, the resulting Hamiltonian is found to be
non-Hermitian.


title: PBW bases and marginally large tableaux in type D

abstract:
  We give an explicit description of the unique crystal isomorphism between two
realizations of $B(\infty)$ in type $D$: that using marginally large tableaux
and that using PBW monomials with respect to one particularly nice reduced
expression of the longest word.


title: A Locally Adaptive Normal Distribution

abstract:
  The multivariate normal density is a monotonic function of the distance to
the mean, and its ellipsoidal shape is due to the underlying Euclidean metric.
We suggest to replace this metric with a locally adaptive, smoothly changing
(Riemannian) metric that favors regions of high local density. The resulting
locally adaptive normal distribution (LAND) is a generalization of the normal
distribution to the "manifold" setting, where data is assumed to lie near a
potentially low-dimensional manifold embedded in $\mathbb{R}^D$. The LAND is
parametric, depending only on a mean and a covariance, and is the maximum
entropy distribution under the given metric. The underlying metric is, however,
non-parametric. We develop a maximum likelihood algorithm to infer the
distribution parameters that relies on a combination of gradient descent and
Monte Carlo integration. We further extend the LAND to mixture models, and
provide the corresponding EM algorithm. We demonstrate the efficiency of the
LAND to fit non-trivial probability distributions over both synthetic data, and
EEG measurements of human sleep.


title: Improved Approximations for Some Polymer Extension Models

abstract:
  We propose approximations for force-extension dependencies for the freely
jointed chain (FJC) and worm-like chain (WLC) models as well as for
extension-force dependence for the WLC model. Proposed expressions show less
than 1% relative error in the useful range of the corresponding variables.
These results can be applied for fitting force-extension curves obtained in
molecular force spectroscopy experiments. Particularly they can be useful for
cases where one has geometries of springs in series and/or in parallel where
particular combination of expressions should be used for fitting the data. All
approximations have been obtained following the same procedure of determining
the asymptotes and then reducing the relative error of that expression by
adding an appropriate term obtained from fitting its absolute error.


title:
A Perturbative Approach to the Redshift Space Power Spectrum: Beyond the
  Standard Model

abstract:
  We develop a code to produce the power spectrum in redshift space based on
standard perturbation theory (SPT) at 1-loop order. The code can be applied to
a wide range of modified gravity and dark energy models using a recently
proposed numerical method by A.Taruya. This includes Horndeski's theory with a
general potential, which accommodates both chameleon and Vainshtein screening
mechanisms and provides a non-linear extension of the effective theory of dark
energy up to third order. Focus is on a recent non-linear model of the redshift
space power spectrum which has been shown to model the anisotropy very well at
relevant scales for the SPT framework, as well as capturing relevant non-linear
effects typical of modified gravity theories. We provide consistency checks of
the code against established results and elucidate it's application within the
light of upcoming high precision RSD data.


title: On finite GK-dimensional Nichols algebras over abelian groups

abstract:
  We contribute to the classification of Hopf algebras with finite
Gelfand-Kirillov dimension, $\operatorname{GKdim}$ for short, through the study
of Nichols algebras over abelian groups. We deal first with braided vector
spaces over $\mathbb Z$ with the generator acting as a single Jordan block and
show that the corresponding Nichols algebra has finite $\operatorname{GKdim}$
if and only if the size of the block is 2 and the eigenvalue is $\pm 1$; when
this is 1, we recover the quantum Jordan plane. We consider next a class of
braided vector spaces that are direct sums of blocks and points that contains
those of diagonal type. We conjecture that a Nichols algebra of diagonal type
has finite $\operatorname{GKdim}$ if and only if the corresponding generalized
root system is finite. Assuming the validity of this conjecture, we classify
all braided vector spaces in the mentioned class whose Nichols algebra has
finite $\operatorname{GKdim}$. Consequently we present several new examples of
Nichols algebras with finite $\operatorname{GKdim}$, including two not in the
class alluded to above. We determine which among these Nichols algebras are
domains.


title: On uniqueness of T-duality with spectators

abstract:
  We investigate the dependence of nonabelian T-duality on various
identification of the group of target space isometries of nonlinear sigma
models with its orbits, i.e. with respect to the location of the group unit on
manifolds invariant under the isometry group. We show that T-duals constructed
by isometry groups of dimension less than the dimension of the
(pseudo)riemannian manifold may depend not only on the initial metric but also
on the choice of manifolds defining positions of group units on each of the
submanifold invariant under the isometry group. We investigate whether this
dependence can be compensated by coordinate transformation.


title:
On the induced gravitational collapse scenario of gamma-ray bursts
  associated with supernovae

abstract:
  Following the induced gravitational collapse (IGC) paradigm of gamma-ray
bursts (GRBs) associated with type Ib/c supernovae, we present numerical
simulations of the explosion of a carbon-oxygen (CO) core in a binary system
with a neutron-star (NS) companion. The supernova ejecta trigger a
\emph{hypercritical} accretion process onto the NS thanks to a copious neutrino
emission and the trapping of photons within the accretion flow. We show that
temperatures 1--10~MeV develop near the NS surface, hence electron-positron
annihilation into neutrinos becomes the main cooling channel leading to
accretion rates $10^{-9}$--$10^{-1}~M_\odot$~s$^{-1}$ and neutrino luminosities
$10^{43}$--$10^{52}$~erg~s$^{-1}$ (the shorter the orbital period the higher
the accretion rate). We estimate the maximum orbital period, $P_{\rm max}$, as
a function of the NS initial mass, up to which the NS companion can reach by
hypercritical accretion the critical mass for gravitational collapse leading to
black-hole (BH) formation. We then estimate the effects of the accreting and
orbiting NS companion onto a novel geometry of the supernova ejecta density
profile. We present the results of a $1.4\times 10^7$~particle simulation which
show that the NS induces accentuated asymmetries in the ejecta density around
the orbital plane. We elaborate on the observables associated with the above
features of the IGC process. We apply this framework to specific GRBs: we find
that X-ray flashes (XRFs) and binary-driven hypernovae (BdHNe) are produced in
binaries with $P>P_{\rm max}$ and $P < P_{\rm max}$, respectively. We analyze
in detail the case of XRF 060218.


title: On questions of Cassels and Drungilas-Dubickas

abstract:
  We answer a question of Drungilas-Dubickas in the affirmative under the
assumption of standard conjectures on smooth numbers in polynomial sequences.
This gives evidence against the "Dubickas Conjecture", which Ka\v{c}inskait\.e
and Laurin\v{c}ikas proved implies universality results for the Hurwitz
zeta-function with certain algebraic irrational parameters.
  Under these standard conjectures we also prove some results that confirms
observations of Worley relating to a problem of Cassels on the multiplicative
dependence of algebraic numbers shifted by integers.


title: Probabilistic counterparts of nonlinear parabolic PDE systems

abstract:
  We extend the results of the FBSDE theory in order to construct a
probabilistic representation of a viscosity solution to the Cauchy problem for
a system of quasilinear parabolic equations. We derive a BSDE associated with a
class of quailinear parabolic system and prove the existence and uniqueness of
its solution. To be able to deal with systems including nondiagonal first order
terms along with the underlying diffusion process we consider its
multiplicative operator functional. We essentially exploit as well the fact
that the system under consideration can be reduced to a scalar equation in a
enlarged phase space. This allows to obtain some comparison theorems and to
prove that a solution to FBSDE gives rise to a viscosity solution of the
original Cauchy problem for a system of quasilinear parabolic equations.


title: Integrable order parameter dynamics of globally coupled oscillators

abstract:
  We study the nonlinear dynamics of globally coupled nonidentical oscillators
in the framework of two order parameter (mean field and amplitude-frequency
correlator) reduction. The main result of the paper is the exact solution of
the corresponding nonlinear system on an attracting manifold. We present a
complete classification of phase portraits and bifurcations, obtain explicit
expressions for invariant manifolds (a limit cycle among them) and derive
analytical solutions for arbitrary initial data and different regimes.


title: Franck-Condon Blockade in a Single-Molecule Transistor

abstract:
  We investigate vibron-assisted electron transport in single-molecule
transistors containing an individual Fe4 Single-Molecule Magnet. We observe a
strong suppression of the tunneling current at low bias in combination with
vibron-assisted excitations. The observed features are explained by a strong
electron-vibron coupling in the framework of the Franck-Condon model supported
by density-functional theory.


title:
Phase Competition, Solitons, and Domain Walls in Neutral-Ionic
  Transition Systems

abstract:
  Phase competition and excitations in the one-dimensional neutral-ionic
transition systems are theoretically studied comprehensively. From the
semiclassical treatment of the bosonized Hamiltonian, we examine the
competition among the neutral (N), ferroelectric-ionic (I$_\mathrm{ferro}$) and
paraelectric-ionic (I$_\mathrm{para}$) states. The phase transitions between
them can become first-order when the fluctuation-induced higher-order
commensurability potential is considered. In particular, the description of the
first-order phase boundary between N and I$_\mathrm{ferro}$ enables us to
analyze N-I$_\mathrm{ferro}$ domain walls. Soliton excitations in the three
phases are described explicitly and their formation energies are evaluated
across the phase boundaries. The characters of the soliton and domain-wall
excitations are classified in terms of the topological charge and spin. The
relevance to the experimental observations in the molecular neutral-ionic
transition systems is discussed. We ascribe the pressure-induced crossover in
tetrathiafulvalene-$p$-chloranil (TTF-CA) at a high-temperature region to that
from the N to the I$_\mathrm{para}$ state, and discuss its consequence.


title: Coordination Annotation Extension in the Penn Tree Bank

abstract:
  Coordination is an important and common syntactic construction which is not
handled well by state of the art parsers. Coordinations in the Penn Treebank
are missing internal structure in many cases, do not include explicit marking
of the conjuncts and contain various errors and inconsistencies. In this work,
we initiated manual annotation process for solving these issues. We identify
the different elements in a coordination phrase and label each element with its
function. We add phrase boundaries when these are missing, unify
inconsistencies, and fix errors. The outcome is an extension of the PTB that
includes consistent and detailed structures for coordinations. We make the
coordination annotation publicly available, in hope that they will facilitate
further research into coordination disambiguation.


title:
A Stringent Limit on the Warm Dark Matter Particle Masses from the
  Abundance of z=6 Galaxies in the Hubble Frontier Fields

abstract:
  We show that the recently measured UV luminosity functions of ultra-faint
lensed galaxies at z= 6 in the Hubble Frontier Fields provide an unprecedented
probe for the mass m_X of the Warm Dark Matter candidates independent of
baryonic physics. Comparing the measured abundance of the faintest galaxies
with the maximum number density of dark matter halos in WDM cosmologies sets a
robust limit m_X> 2.9 keV for the mass of thermal relic WDM particles at a
1-sigma confidence level, m_X> 2.4 keV at 2-sigma, and m_X> 2.1 keV at 3-sigma.
These constitute the tightest constraints on WDM particle mass derived to date
independently of the baryonic physics involved in galaxy formation. We discuss
the impact of our results on the production mechanism of sterile neutrinos. In
particular, if sterile neutrinos are responsible for the 3.5 keV line reported
in observations of X-ray clusters, our results firmly rule out the
Dodelson-Widrow production mechanism, and yield m_{sterile}> 6.1 keV for
sterile neutrinos produced via the Shi-Fuller mechanism.


title:
Reconstruction of air shower muon densities using segmented counters
  with time resolution

abstract:
  Despite the significant experimental effort made in the last decades, the
origin of the ultra-high energy cosmic rays is still largely unknown. Key
astrophysical information to identify where these energetic particles come from
is provided by their chemical composition. It is well known that a very
sensitive tracer of the primary particle type is the muon content of the
showers generated by the interaction of the cosmic rays with air molecules. We
introduce a likelihood function to reconstruct particle densities using
segmented detectors with time resolution. As an example of this general method,
we fit the muon distribution at ground level using an array of counters like
AMIGA, one of the Pierre Auger Observatory detectors. For this particular case
we compare the reconstruction performance against a previous method. With the
new technique, more events can be reconstructed than before. In addition the
statistical uncertainty of the measured number of muons is reduced, allowing
for a better discrimination of the cosmic ray primary mass.


title: Extraction of Gravitational Waves in Numerical Relativity

abstract:
  A numerical-relativity calculation yields in general a solution of the
Einstein equations including also a radiative part, which is in practice
computed in a region of finite extent. Since gravitational radiation is
properly defined only at null infinity and in an appropriate coordinate system,
the accurate estimation of the emitted gravitational waves represents an old
and non-trivial problem in numerical relativity. A number of methods have been
developed over the years to "extract" the radiative part of the solution from a
numerical simulation and these include: quadrupole formulas, gauge-invariant
metric perturbations, Weyl scalars, and characteristic extraction. We review
and discuss each method, in terms of both its theoretical background as well as
its implementation. Finally, we provide a brief comparison of the various
methods in terms of their inherent advantages and disadvantages.


title: Alkalized Borazine: A Simple Recipe to Design Superalkali Species

abstract:
  We propose a simple yet effective route to the design of superalkalis, by
successive alkali metal substitution in borazine (B3N3H6). Using Li atoms, our
density functional calculations demonstrate that the vertical ionization energy
(VIE) of B3N3H6-xLix decreases with the increase in x for x equals 1-6. For x
equals 4, the VIE of B3N3H6-xLix becomes lower than that of Li atom, thereby
indicating their superalkali nature. More interestingly, all these species are
planar such that NICSzz value at the rings center is reduced. These novel
superalkalis are expected to stimulate further interests in this field.


title: Protector Control PC-AODV-BH in The Ad Hoc Networks

abstract:
  In this paper we deal with the protector control that which we used to secure
AODV routing protocol in Ad Hoc networks. The considered system can be
vulnerable to several attacks because of mobility and absence of
infrastructure. While the disturbance is assumed to be of the black hole type,
we purpose a control named "PC-AODV-BH" in order to neutralize the effects of
malicious nodes. Such a protocol is obtained by coupling hash functions,
digital signatures and fidelity concept. An implementation under NS2 simulator
will be given to compare our proposed approach with SAODV protocol, basing on
three performance metrics and taking into account the number of black hole
malicious nodes


title: $W_4$ Toda example as hidden Liouville CFT

abstract:
  We construct correlators in the $W_4$ Toda 2d conformal field theory for a
particular class of representations and demonstrate a relation to a $W_2$
(Virasoro) theory with different central charge. The relevance of the classical
limits of the constructed 3-point functions and braiding matrices to problems
in 4d conformal theories is discussed.


title:
The forecasting of menstruation based on a state-space modeling of basal
  body temperature time series

abstract:
  Women's basal body temperature (BBT) follows a periodic pattern that is
associated with the events in their menstrual cycle. Although daily BBT time
series contain potentially useful information for estimating the underlying
menstrual phase and for predicting the length of current menstrual cycle, few
models have been constructed for BBT time series. Here, we propose a
state-space model that includes menstrual phase as a latent state variable to
explain fluctuations in BBT and menstrual cycle length. Conditional
distributions for the menstrual phase were obtained by using sequential
Bayesian filtering techniques. A predictive distribution for the upcoming onset
of menstruation was then derived based on the conditional distributions and the
model, leading to a novel statistical framework that provided a sequentially
updated prediction of the day of onset of menstruation. We applied this
framework to a real dataset comprising women's self-reported BBT and days of
menstruation, comparing the prediction accuracy of our proposed method with
that of conventional calendar calculation. We found that our proposed method
provided a better prediction of the day of onset of menstruation. Potential
extensions of this framework may provide the basis of modeling and predicting
other events that are associated with the menstrual cycle.


title: Prospects for Primordial Gravitational Waves in String Inflation

abstract:
  Assuming that the early universe had (i) a description using perturbative
string theory and its field theory limit (ii) an epoch of slow-roll inflation
within a four-dimensional effective field theory and a hierarchy of scales
$M_{inf} < m_{kk} < m_s \lesssim M_{pl}$ that keeps the latter under control,
we derive an upper bound on the amplitude of primordial gravitational waves.
The bound is very sensitive to mild changes in numerical coefficients and the
expansion parameters. For example, allowing couplings and mass-squared
hierarchies $\lesssim 0.2$, implies $r \lesssim 0.05$, but asking more safely
for hierarchies $\lesssim 0.1$, the bound becomes $r \lesssim 10^{-6}$.
Moreover, large volumes -- typically used in string models to keep backreaction
and moduli stabilisation under control -- drive $r$ down. Consequently, any
detection of inflationary gravitational waves would present an interesting but
difficult challenge for string theory.


title:
Other quantum relatives of the Alexander polynomial through the
  Links-Gould invariants

abstract:
  Oleg Viro studied in arXiv:math/0204290 two interpretations of the
(multivariable) Alexander polynomial as a quantum link invariant: either by
considering the quasi triangular Hopf algebra associated to $U_q sl(2)$ at
fourth roots of unity, or by considering the super Hopf algebra $U_q gl(1|1)$.
In this paper, we show these Hopf algebras share properties with the $-1$
specialization of $U_q gl(n|1)$ leading to the proof of a conjecture of David
De Wit, Atsushi Ishii and Jon Links on the Links-Gould invariants.


title:
Invariant Einstein metrics on generalized flag manifolds of $Sp(n)$ and
  $SO(2n)$

abstract:
  It is well known that the Einstein equation on a Riemannian flag manifold
$(G/K,g)$ reduces to an algebraic system if $g$ is a $G$-invariant metric. In
this paper we obtain explicitly new invariant Einstein metrics on generalized
flag manifolds of $Sp(n)$ and $SO(2n)$; and we compute the Einstein system for
generalized flag manifolds of type $Sp(n)$. We also consider the isometric
problem for these Einstein metrics.


title: Helically Decomposed Turbulence

abstract:
  A decomposition of the energy and helicity fluxes in a turbulent hydrodynamic
flow is proposed. The decomposition is based on the projection of the flow to a
helical basis that allows to investigate separately the role of interactions
among modes of different helicity. The proposed formalism is then applied in
large scale numerical simulations of a non-helical and a helical flow, where
the decomposed fluxes are explicitly calculated. It is shown that the total
energy flux can be split in to three fluxes that independently remain constant
in the inertial range. One of these fluxes that corresponds to the interactions
of fields with the same helicity is negative implying the presence of an
inverse cascade that is `hidden' inside the forward cascade. Similar to the
energy flux the helicity flux is also shown that it can be decomposed to two
fluxes that remain constant in the inertial range. Implications of these
results as well possible new directions for investigations are discussed.


title: On kernels and nuclei of rank metric codes

abstract:
  For each rank metric code $\mathcal{C}\subseteq \mathbb{K}^{m\times n}$, we
associate a translation structure, the kernel of which is shown to be invariant
with respect to the equivalence on rank metric codes. When $\mathcal{C}$ is
$\mathbb{K}$-linear, we also propose and investigate other two invariants
called its middle nucleus and right nucleus. When $\mathbb{K}$ is a finite
field $\mathbb{F}_q$ and $\mathcal{C}$ is a maximum rank distance code with
minimum distance $d<\min\{m,n\}$ or $\gcd(m,n)=1$, the kernel of the associated
translation structure is proved to be $\mathbb{F}_q$. Furthermore, we also show
that the middle nucleus of a linear maximum rank distance code over
$\mathbb{F}_q$ must be a finite field; its right nucleus also has to be a
finite field under the condition $\max\{d,m-d+2\} \geqslant \left\lfloor
\frac{n}{2} \right\rfloor +1$. Let $\mathcal{D}$ be the DHO-set associated with
a bilinear dimensional dual hyperoval over $\mathbb{F}_2$. The set
$\mathcal{D}$ gives rise to a linear rank metric code, and we show that its
kernel and right nucleus are is isomorphic to $\mathbb{F}_2$. Also, its middle
nucleus must be a finite field containing $\mathbb{F}_q$. Moreover, we also
consider the kernel and the nuclei of $\mathcal{D}^k$ where $k$ is a Knuth
operation.


title: Symbolic Music Data Version 1.0

abstract:
  In this document, we introduce a new dataset designed for training machine
learning models of symbolic music data. Five datasets are provided, one of
which is from a newly collected corpus of 20K midi files. We describe our
preprocessing and cleaning pipeline, which includes the exclusion of a number
of files based on scores from a previously developed probabilistic machine
learning model. We also define training, testing and validation splits for the
new dataset, based on a clustering scheme which we also describe. Some simple
histograms are included.


title:
Impact parameter moments for ionization of Ne, Ar, Kr, and Xe by
  protons, considering different initial states and impact energies

abstract:
  Tables of ab-initio total cross sections, probabilities at zero impact
parameter, and impact parameter moments are presented concerning the ionization
of Ne, Ar, Kr, and Xe by proton impact in the energy range (0.1-10) MeV.
Calculations correspond to the continuum distorted wave eikonal initial state
approximation (CDW-EIS) for energies up to 1MeV, and to the first Born
approximation for larger energies. Results displayed in the tables are
disaggregated for the different initial bound states, considering all shells
for Ne and Ar, L-M-N shells of Kr and M-N-O shells of Xe. Our inner-shell
ionization cross sections are compared with the available experimental data and
with the ECPSSR results.


title: Strengthening topological colorful results for graphs

abstract:
  Various results ensure the existence of large complete bipartite graphs in
properly colored graphs when some condition related to a topological lower
bound on the chromatic number is satisfied. We generalize three theorems of
this kind, respectively due to Simonyi and Tardos (Combinatorica, 2006),
Simonyi, Tardif, and Zsb\'an (The Electronic Journal of Combinatorics, 2013),
and Chen (Journal of Combinatorial Theory, Series A, 2011). As a consequence of
the generalization of Chen's theorem, we get new families of graphs whose
chromatic number equals their circular chromatic number and that satisfy
Hedetniemi's conjecture for the circular chromatic number.


title:
Monitoramento de redes sociais analise de ferramenta com foco no retorno
  estrategico empresarial (Monitoring social networks analysis tool focused on
  strategic business return)

abstract:
  With the recent emergence and the explosion of users in social networks,
Internet users have come to know more about other people or companies through
information obtained from online groups or communities and therefore meet new
opportunities. An avalanche of diverse and unstructured information is created
every minute, for billions of devices connected to the Internet all the time.
Analyze, process, understand and evaluate these data, it is a challenging task,
given the volume, velocity and variety of information from these social
networks. However, a better understanding of the process of monitoring networks
and the use of tools of this kind are essential for people, companies and the
academic world. The application of monitoring systems, information management
and the possibility of bringing brands to people, are some positives that this
research will provide better knowledge of the problems. In this research will
be analyzed monitoring tool of social networks SCUP, its details, its features
and the tool related to business management. In conclusion, we present all the
peculiarities of the software and the possibilities applicable in the corporate
environment, as aid to decision making.


title: Estimation of solar irradiance using ground-based whole sky imagers

abstract:
  Ground-based whole sky imagers (WSIs) can provide localized images of the sky
of high temporal and spatial resolution, which permits fine-grained cloud
observation. In this paper, we show how images taken by WSIs can be used to
estimate solar radiation. Sky cameras are useful here because they provide
additional information about cloud movement and coverage, which are otherwise
not available from weather station data. Our setup includes ground-based
weather stations at the same location as the imagers. We use their measurements
to validate our methods.


title:
Help, Anyone? A User Study For Modeling Robotic Behavior To Mitigate
  Malfunctions With The Help Of The User

abstract:
  Service robots for the domestic environment are intended to autonomously
provide support for their users. However, state-of-the-art robots still often
get stuck in failure situations leading to breakdowns in the interaction flow
from which the robot cannot recover alone. We performed a multi-user
Wizard-of-Oz experiment in which we manipulated the robot's behavior in such a
way that it appeared unexpected and malfunctioning, and asked participants to
help the robot in order to restore the interaction flow. We examined how
participants reacted to the robot's error, its subsequent request for help and
how it changed their perception of the robot with respect to perceived
intelligence, likability, and task contribution. As interaction scenario we
used a game of building Lego models performed by user dyads. In total 38
participants interacted with the robot and helped in malfunctioning situations.
We report two major findings: (1) in user dyads, the user who gave the last
command followed by the user who is closer is more likely to help (2)
malfunctions that can be actively fixed by the user seem not to negatively
impact perceived intelligence and likability ratings. This work offers insights
in how far user support can be a strategy for domestic service robots to
recover from repeating malfunctions.


title:
A Dipole on the Sky: Predictions for Hypervelocity Stars from the Large
  Magellanic Cloud

abstract:
  We predict the distribution of hypervelocity stars (HVSs) ejected from the
Large Magellanic Cloud (LMC), under the assumption that the dwarf galaxy hosts
a central massive black hole (MBH). For the majority of stars ejected from the
LMC the orbital velocity of the LMC has contributed a significant fraction of
their galactic rest frame velocity, leading to a dipole density distribution on
the sky. We quantify the dipole using spherical harmonic analysis and contrast
with the monopole expected for HVSs ejected from the Galactic Center. There is
a tendril in the density distribution that leads the LMC which is coincident
with the well-known and unexplained clustering of HVSs in the constellations of
Leo and Sextans. Our model is falsifiable, since it predicts that Gaia will
reveal a large density of HVSs in the southern hemisphere.


title: Energy Decay in a Wave Guide with Dissipation at Infinity

abstract:
  We prove local and global energy decay for the wave equation in a wave guide
with damping at infinity. More precisely, the absorption index is assumed to
converge slowly to a positive constant, and we obtain the diffusive phenomenon
typical for the contribution of low frequencies when the damping is effective
at infinity. On the other hand, the usual Geometric Control Condition is not
necessarily satisfied so we may have a loss of regularity for the contribution
of high frequencies. Since our results are new even in the Euclidean space, we
also state a similar result in this case.


title: Face numbers and the fundamental group

abstract:
  We resolve a conjecture of Kalai asserting that the $g_2$-number of any
simplicial complex $\Delta$ that represents a connected normal pseudomanifold
of dimension $d\geq 3$ is at least as large as ${d+2 \choose 2}m(\Delta)$,
where $m(\Delta)$ denotes the minimum number of generators of the fundamental
group of $\Delta$. Furthermore, we prove that a weaker bound, $h_2(\Delta)\geq
{d+1 \choose 2}m(\Delta)$, applies to any $d$-dimensional pure simplicial poset
$\Delta$ all of whose faces of co-dimension $\geq 2$ have connected links. This
generalizes a result of Klee. Finally, for a pure relative simplicial poset
$\Psi$ all of whose vertex links satisfy Serre's condition $(S_r)$, we
establish lower bounds on $h_1(\Psi),\ldots,h_r(\Psi)$ in terms of the
$\mu$-numbers introduced by Bagchi and Datta.


title: The masterpieces of John Forbes Nash Jr

abstract:
  In this note I have tried to rewrite four famous works of Nash in a more
modern language while adhering as much as possible to the original arguments.


title: Fast Switch Scanning Keyboards: Minimal Expected Query Decision Trees

abstract:
  Augmentative and Alternative Communication (AAC) systems allow people with
disabilities to provide input to devices which empower them to more fully
interact with their environment. Within AAC, switch scanning is a common
paradigm for spelling where a set of characters is highlighted and the user is
queried as to whether their target character is in the highlighted set. These
queries are used to traverse a decision tree which successively prunes away
characters until only a single one remains (the estimate). This work seeks a
decision tree which requires the fewest expected queries per decision sequence
(EQPD). In particular, we remove the constraint that the decision tree needs to
be a row-item or group-row-item style tree and minimize EQPD. We pose the
problem as a Huffman code with variable, integer cost and solve it with a mild
extension of Golin's method in "A dynamic programming algorithm for
constructing optimal prefix-free codes with unequal letter costs", IEEE
Transactions on Information Theory (1998). Additionally, we model the user on
the query level by their probability of detection and false alarm to derive
their expected performance on the character level given some decision tree. We
perform experiments which show that the min EQPD decision tree (Karp) may
reduce selection times, especially for timed (single switch) switch scanning.


title:
The Oslo model, hyperuniformity, and the quenched Edwards-Wilkinson
  model

abstract:
  We present simulations of the 1-dimensional Oslo rice pile model in which the
critical height at each site is randomly reset after each toppling. We use the
fact that the stationary state of this sandpile model is hyperuniform to reach
system of sizes $> 10^7$. Most previous simulations were seriously flawed by
important finite size corrections. We find that all critical exponents have
values consistent with simple rationals: $\nu=4/3$ for the correlation length
exponent, $D =9/4$ for the fractal dimension of avalanche clusters, and $z=10/7
$ for the dynamical exponent. In addition we relate the hyperuniformity
exponent to the correlation length exponent $\nu$. Finally we discuss the
relationship with the quenched Edwards-Wilkinson (qEW) model, where we find in
particular that the local roughness exponent is $\alpha_{\rm loc} = 1$.


title:
Chern-Simons Invariants on Hyperbolic Manifolds and Topological Quantum
  Field Theories

abstract:
  We derive formulas for the classical Chern-Simons invariant of irreducible
$SU(n)$-flat connections on negatively curved locally symmetric
three-manifolds. We determine the condition for which the theory remains
consistent (with basic physical principles). We show that a connection between
holomorphic values of Selberg-type functions at point zero, associated with
R-torsion of the flat bundle, and twisted Dirac operators acting on negatively
curved manifolds, can be interpreted by means of the Chern-Simons invariant. On
the basis of Labastida-Marino-Ooguri-Vafa conjecture we analyze a
representation of the Chern-Simons quantum partition function (as a generating
series of quantum group invariants) in the form of an infinite product weighted
by S-functions and Selberg-type functions. We consider the case of links and a
knot and use the Rogers approach to discover certain symmetry and modular form
identities.


title: Improving Recurrent Neural Networks For Sequence Labelling

abstract:
  In this paper we study different types of Recurrent Neural Networks (RNN) for
sequence labeling tasks. We propose two new variants of RNNs integrating
improvements for sequence labeling, and we compare them to the more traditional
Elman and Jordan RNNs. We compare all models, either traditional or new, on
four distinct tasks of sequence labeling: two on Spoken Language Understanding
(ATIS and MEDIA); and two of POS tagging for the French Treebank (FTB) and the
Penn Treebank (PTB) corpora. The results show that our new variants of RNNs are
always more effective than the others.


title: DISCO Nets: DISsimilarity COefficient Networks

abstract:
  We present a new type of probabilistic model which we call DISsimilarity
COefficient Networks (DISCO Nets). DISCO Nets allow us to efficiently sample
from a posterior distribution parametrised by a neural network. During
training, DISCO Nets are learned by minimising the dissimilarity coefficient
between the true distribution and the estimated distribution. This allows us to
tailor the training to the loss related to the task at hand. We empirically
show that (i) by modeling uncertainty on the output value, DISCO Nets
outperform equivalent non-probabilistic predictive networks and (ii) DISCO Nets
accurately model the uncertainty of the output, outperforming existing
probabilistic models based on deep neural networks.