title:
Understanding the Mass-Radius Relation for Sub-Neptunes: Radius as a
  Proxy for Composition

abstract:
  Transiting planet surveys like Kepler have provided a wealth of information
on the distribution of planetary radii, particularly for the new populations of
super-Earth and sub-Neptune sized planets. In order to aid in the physical
interpretation of these radii, we compute model radii for low-mass rocky
planets with hydrogen-helium envelopes. We provide model radii for planets 1-20
Earth masses, with envelope fractions from 0.01-20%, levels of irradiation
0.1-1000x Earth's, and ages from 100 Myr to 10 Gyr. In addition we provide
simple analytic fits that summarize how radius depends on each of these
parameters. Most importantly, we show that at fixed composition, radii show
little dependence on mass for planets with more than ~1% of their mass in their
envelope. Consequently, planetary radius is to first order a proxy for
planetary composition for Neptune and sub-Neptune sized planets. We recast the
observed mass-radius relationship as a mass-composition relationship and
discuss it in light of traditional core accretion theory. We discuss the
transition from rocky super-Earths to sub-Neptune planets with large volatile
envelopes. We suggest 1.75 Earth radii as a physically motivated dividing line
between these two populations of planets. Finally, we discuss these results in
light of the observed radius occurrence distribution found by Kepler.


title:
Borel and Hausdorff Hierarchies in Topological Spaces of Choquet Games
  and Their Effectivization

abstract:
  What parts of classical descriptive set theory done in Polish spaces still
hold for more general topological spaces, possibly T0 or T1, but not T2 (i.e.
not Hausdorff)? This question has been addressed by Victor Selivanov in a
series of papers centered on algebraic domains. And recently it has been
considered by Matthew de Brecht for quasi-Polish spaces, a framework that
contains both countably based continuous domains and Polish spaces. In this
paper we present alternative unifying topological spaces, that we call
approximation spaces. They are exactly the spaces for which player Nonempty has
a stationary strategy in the Choquet game. A natural proper subclass of
approximation spaces coincides with the class of quasi-Polish spaces. We study
the Borel and Hausdorff difference hierarchies in approximation spaces,
revisiting the work done for the other topological spaces. We also consider the
problem of effectivization of these results.


title: Wadge Hardness in Scott Spaces and Its Effectivization

abstract:
  We prove some results on the Wadge order on the space of sets of natural
numbers endowed with Scott topology, and more generally, on omega-continuous
domains. Using alternating decreasing chains we characterize the property of
Wadge hardness for the classes of the Hausdorff difference hierarchy (iterated
differences of open sets). A similar characterization holds for Wadge
one-to-one and finite-to-one completeness. We consider the same questions for
the effectivization of the Wadge relation. We also show that for the space of
sets of natural numbers endowed with the Scott topology, in each class of the
Hausdorff difference hierarchy there are two strictly increasing chains of
Wadge degrees of sets properly in that class. The length of these chains is the
rank of the considered class, and each element in one chain is incomparable
with all the elements in the other chain.


title: On Simply Normal Numbers to Different Bases

abstract:
  Let s be an integer greater than or equal to 2. A real number is simply
normal to base s if in its base-s expansion every digit 0, 1, ..., s-1 occurs
with the same frequency 1/s. Let X be the set of positive integers that are not
perfect powers, hence X is the set {2,3, 5,6,7,10,11,...} . Let M be a function
from X to sets of positive integers such that, for each s in X, if m is in M(s)
then each divisor of m is in M(s) and if M(s) is infinite then it is equal to
the set of all positive integers. These conditions on M are necessary for there
to be a real number which is simply normal to exactly the bases s^m such that s
is in X and m is in M(s). We show these conditions are also sufficient and
further establish that the set of real numbers that satisfy them has full
Hausdorff dimension. This extends a result of W. M. Schmidt (1961/1962) on
normal numbers to different bases.


title: On the Normality of Numbers to Different Bases

abstract:
  We prove independence of normality to different bases We show that the set of
real numbers that are normal to some base is Sigma^0_4 complete in the Borel
hierarchy of subsets of real numbers. This was an open problem, initiated by
Alexander Kechris, and conjectured by Ditzen 20 years ago.


title:
Temperature dependent nucleation and propagation of domain walls in a
  sub-100 nm perpendicularly magnetized Co/Ni multilayer

abstract:
  We present a study of the temperature dependence of the switching fields in
Co/Ni-based perpendicularly magnetized spin-valves. While magnetization
reversal of all-perpendicular Co/Ni spin valves at ambient temperatures is
typically marked by a single sharp step change in resistance, low temperature
measurements can reveal a series of resistance steps, consistent with
non-uniform magnetization configurations. We propose a model that consists of
domain nucleation, propagation and annihilation to explain the temperature
dependence of the switching fields. Interestingly, low temperature (<30 K) step
changes in resistance that we associate with domain nucleation, have a bimodal
switching field and resistance step distribution, attributable to two competing
nucleation pathways.


title: Normal Numbers and the Borel Hierarchy

abstract:
  We show that the set of absolutely normal numbers is $\mathbf
\Pi^0_3$-complete in the Borel hierarchy of subsets of real numbers. Similarly,
the set of absolutely normal numbers is $\Pi^0_3$-complete in the effective
Borel hierarchy.


title:
Surface Alignment, Anchoring Transitions, Optical Properties, and
  Topological Defects in the Thermotropic Nematic Phase of an Organo-Siloxane
  Tetrapodes

abstract:
  We perform optical, surface anchoring, and textural studies of an
organo-siloxane tetrapode material in the broad temperature range of the
nematic phase. The optical, structural, and topological features are compatible
with the uniaxial nematic order rather than with the biaxial nematic order, in
the entire nematic temperature range -25C < T < 46C studied. For homeotropic
alignment, the material experiences surface anchoring transition, but the
director can be realigned into an optically uniaxial texture by applying a
sufficiently strong electric field. The topological features of textures in
cylindrical capillaries, in spherical droplets and around colloidal inclusions
are consistent with the uniaxial character of the long-range nematic order. In
particular, we observe isolated surface point defect-boojums and bulk point
defects-hedgehog that can exist only in the uniaxial nematic.


title: Interface-induced magnetism in perovskite quantum wells

abstract:
  We investigate the angular dependence of the magnetoresistance of thin (< 1
nm), metallic SrTiO3 quantum wells epitaxially embedded in insulating,
ferrimagnetic GdTiO3 and insulating, antiferromagnetic SmTiO3, respectively.
The SrTiO3 quantum wells contain a high density of mobile electrons (~7x10^14
cm^-2). We show that the longitudinal and transverse magnetoresistance in the
structures with GdTiO3 are consistent with anisotropic magnetoresistance, and
thus indicative of induced ferromagnetism in the SrTiO3, rather than a
nonequilibrium proximity effect. Comparison with the structures with
antiferromagnetic SmTiO3 shows that the properties of thin SrTiO3 quantum wells
can be tuned to obtain magnetic states that do not exist in the bulk material.


title:
Giant fluctuations of local magnetoresistance of organic spin valves and
  non-hermitian 1D Anderson model

abstract:
  Motivated by recent experiments, where the tunnel magnetoresitance (TMR) of a
spin valve was measured locally, we theoretically study the distribution of TMR
along the surface of magnetized electrodes. We show that, even in the absence
of interfacial effects (like hybridization due to donor and acceptor
molecules), this distribution is very broad, and the portion of area with
negative TMR is appreciable even if on average the TMR is positive. The origin
of the local sign reversal is quantum interference of subsequent spin-rotation
amplitudes in course of incoherent transport of carriers between the source and
the drain. We find the distribution of local TMR exactly by drawing upon formal
similarity between evolution of spinors in time and of reflection coefficient
along a 1D chain in the Anderson model. The results obtained are confirmed by
the numerical simulations.


title:
A Novel Term Weighing Scheme Towards Efficient Crawl of Textual
  Databases

abstract:
  The Hidden Web is the vast repository of informational databases available
only through search form interfaces, accessible by therein typing a set of
keywords in the search forms. Typically, a Hidden Web crawler is employed to
autonomously discover and download pages from the Hidden Web. Traditional
hidden web crawlers do not provide the search engines with an optimal search
experience because of the excessive number of search requests posed through the
form interface so as to exhaustively crawl and retrieve the contents of the
target hidden web database. Here in our work, we provide a framework to
investigate the problem of optimal search and curtail it by proposing an
effective query term selection approach based on the frequency & distribution
of terms in the document database. The paper focuses on developing a
term-weighing scheme called VarDF (acronym for variable document frequency)
that can ease the identification of optimal terms to be used as queries on the
interface for maximizing the achieved coverage of the crawler which in turn
will facilitate the search engine to have a diversified and expanded index. We
experimentally evaluate the effectiveness of our approach on a manually created
database of documents in the area of Information Retrieval.


title:
A concept for laboratory studies of radiation detectors over a broad
  dynamic-range: instabilities evaluation in THGEM-structures

abstract:
  A simple methodology for evaluating the dynamic-range of gas avalanche
detectors in the laboratory is presented and discussed. It comprises two tools:
a charge injector of tunable gain which transfers radiation-induced amplified
electron swarms to the investigated detector to mimic events with well defined
primary-ionization spectra, and a systematic approach for measuring the
detector's discharge probability. The methodology, applicable to a broad range
of detectors, is applied here for instability studies in various single-stage
THGEM and THGEM-WELL structures. The results indicate upon a somewhat larger
attainable dynamic range in a single-stage THGEM operated with additional
multiplication in the induction gap.


title: A Symplectic Representation of $\mathrm{E}_7$

abstract:
  We explicitly construct a particular real form of the Lie algebra
$\mathfrak{e}_7$ in terms of symplectic matrices over the octonions, thus
justifying the identifications $\mathfrak{e}_7\cong\mathfrak{sp}(6,\mathbb{O})$
and, at the group level, $\mathrm{E}_7\cong\mathrm{Sp}(6,\mathbb{O})$. Along
the way, we provide a geometric description of the minimal representation of
$\mathfrak{e}_7$ in terms of rank 3 objects called cubies.


title: Orbital Magnetism Induced by Heat Currents in Mott insulators

abstract:
  We derive the effective heat current density operator for the strong-coupling
regime of Mott insulators. Similarly to the case of the electric current
density, the leading contribution to this effective operator is proportional to
the local scalar spin chirality $\hat{\chi}_{jkl}=
\mathbf{S}_l\cdot\left(\mathbf{S}_j\times \mathbf{S}_k\right)$. This common
form of the effective heat and electric current density operators leads to a
novel cross response in Mott insulators. A heat current induces a distribution
of orbital magnetic moments in systems containing loops of an odd number of
hopping terms. The relative orientation of the orbital moments depends on the
particular lattice of magnetic ions. This subtle effect arises from the
symmetries that the heat and electric currents have in common.


title:
An extension to GUM methodology: degrees-of-freedom calculations for
  correlated multidimensional estimates

abstract:
  The Guide to the Expression of Uncertainty in Measurement advocates the use
of an 'effective number of degrees of freedom' for the calculation of an
interval of measurement uncertainty. However, it does not describe how this
number is to be calculated when (i) the measurand is a vector quantity or (ii)
when the errors in the estimates of the quantities defining the measurand (the
'input quantities') are not incurred independently. An appropriate analysis for
a vector-valued measurand has been described (Metrologia 39 (2002) 361-9), and
a method for a one-dimensional measurand with dependent errors has also been
given (Metrologia 44 (2007) 340-9). This paper builds on those analyses to
present a method for the situation where the problem is multidimensional and
involves correlated errors. The result is an explicit general procedure that
reduces to simpler procedures where appropriate. The example studied is from
the field of radio-frequency metrology, where measured quantities are often
complex-valued and can be regarded as vectors of two elements.


title: Charge-cluster glass in an organic conductor

abstract:
  Geometrically frustrated spin systems often do not exhibit long-range
ordering, resulting in either quantum-mechanically disordered states, such as
quantum spin liquids, or classically disordered states, such as spin ices or
spin glasses. Geometric frustration may play a similar role in charge ordering,
potentially leading to unconventional electronic states without long-range
order; however, there are no previous experimental demonstrations of this
phenomenon. Here, we show that a charge-cluster glass evolves upon cooling in
the absence of long-range charge ordering for an organic conductor with a
triangular lattice, theta-(BEDT-TTF)2RbZn(SCN)4. A combination of time-resolved
transport measurements and x-ray diffraction reveal that the charge-liquid
phase has charge clusters that fluctuate extremely slowly (<10-100 Hz) and
heterogeneously. Upon further cooling, the cluster dynamics freeze, and a
charge-cluster glass is formed. Surprisingly, these observations correspond to
recent ideas regarding the structural glass formation of supercooled liquids,
indicating that a glass-forming charge liquid relates correlated-electron
physics to glass physics in soft matter.


title: On the Sparing Number of Certain Graph Structures

abstract:
  An integer additive set-indexer is defined as an injective function
$f:V(G)\rightarrow 2^{\mathbb{N}_0}$ such that the induced function $g_f:E(G)
\rightarrow 2^{\mathbb{N}_0}$ defined by $g_f (uv) = f(u)+ f(v)$ is also
injective. An IASI $f$ is said to be a weak IASI if
$|g_f(uv)|=max(|f(u)|,|f(v)|)$ for all $u,v\in V(G)$. A graph which admits a
weak IASI may be called a weak IASI graph. The set-indexing number of an
element of a graph $G$, a vertex or an edge, is the cardinality of its
set-labels. A mono-indexed element of a graph is an element of $G$ which has
the set-indexing number $1$. The Sparing number of a graph $G$ is the minimum
number of mono-indexed edges required for a graph $G$ to admit a weak IASI. In
this paper, we introduce the notion of conjoined graphs, entwined graphs and
floral graphs and study further about the sparing number of various finite
graph operations as extensions to our earlier studies and provide some useful
results on these types of graph structures.


title:
Resonantly exited precession motion of three-dimensional vortex core in
  magnetic nanospheres

abstract:
  We found resonantly excited precession motions of a three-dimensional vortex
core in soft magnetic nanospheres and controllable precession frequency with
the sphere diameter 2R, as studied by micromagnetic numerical and analytical
calculations. The precession angular frequency for an applied static field
$H_{DC}$ is given as $\omega_{MV}= \gamma_{eff} H_{DC}$, where $\gamma_{eff} =
\gamma <m_{\Gamma}>$ is the effective gyromagnetic ratio in collective vortex
dynamics, with the gyromagnetic ratio $\gamma$ and the average magnetization
component $<m_{\Gamma}>$ of the ground-state vortex in the core direction.
Fitting to the micromagnetic simulation data for $<m_{\Gamma}>$ yields a simple
explicit form of $<m_{\Gamma}> = (73.6 \pm 3.4)(l_{ex}/2R)^{2.20 \pm 0.14}$,
where $l_{ex}$ is the exchange length of a given material. This dynamic
behavior might serve as a foundation for potential bio-applications of
size-specific resonant excitation of magnetic vortex-state nanoparticles, for
example, magnetic particle resonance imaging.


title:
A Survey on Routing and Data Dissemination in Opportunistic Mobile
  Social Networks

abstract:
  Opportunistic mobile social networks (MSNs) are modern paradigms of delay
tolerant networks that consist of mobile users with social characteristics. The
users in MSNs communicate with each other to share data objects. In this
setting, humans are the carriers of mobile devices, hence their social features
such as movement patterns, similarities, and interests can be exploited to
design efficient data forwarding algorithms. In this paper, an overview of
routing and data dissemination issues in the context of opportunistic MSNs is
presented, with focus on (1) MSN characteristics, (2) human mobility models,
(3) dynamic community detection methods, and (4) routing and data dissemination
protocols. Firstly, characteristics of MSNs which lead to the exposure of
patterns of interaction among mobile users are examined. Secondly, properties
of human mobility models are discussed and recently proposed mobility models
are surveyed. Thirdly, community detection and evolution analysis algorithms
are investigated. Then, a comparative review of state-of-the-art routing and
data dissemination algorithms for MSNs is presented, with special attention
paid to critical issues like context-awareness and user selfishness. Based on
the literature review, some important open issues are finally discussed.


title: Inflation in the Generalized Inverse Power Law Scenario

abstract:
  We propose a single field inflationary model by generalizing the inverse
power law potential from the intermediate model. We study the implication of
our model on the primordial anisotropy of cosmological microwave background
radiation. Specifically, we apply the slow-roll approximation to calculate the
scalar spectral tilt $n_s$ and the tensor-to-scalar ratio $r$. The results are
compared with the recent data measured by the Planck satellite. We found that
by choosing proper values for the parameters, our model can well describe the
Planck data.


title:
Attraction, Merger, Reflection, and Annihilation in Magnetic Droplet
  Soliton Scattering

abstract:
  The interaction behavior of solitons are defining characteristics of these
nonlinear, coherent structures. Due to recent experimental observations, thin
ferromagnetic films offer a promising medium in which to study the scattering
properties of two-dimensional magnetic droplet solitons, particle-like,
precessing dipoles. Here, a rich set of two-droplet interaction behaviors are
classified through micromagnetic simulations. Repulsive and attractive
interaction dynamics are generically determined by the relative phase and
speeds of the two droplets and can be classified into four types: (1) merger
into a breather bound state, (2) counterpropagation trapped along the axis of
symmetry, (3) reflection, and (4) violent droplet annihilation into spin wave
radiation and a breather. Utilizing a nonlinear method of images, it is
demonstrated that these dynamics describe repulsive/attractive scattering of a
single droplet off of a magnetic boundary with pinned/free spin boundary
conditions, respectively. These results explain the mechanism by which
propagating and stationary droplets can be stabilized in a confined
ferromagnet.


title: Sequential Mining: Patterns and Algorithms Analysis

abstract:
  This paper presents and analysis the common existing sequential pattern
mining algorithms. It presents a classifying study of sequential pattern-mining
algorithms into five extensive classes. First, on the basis of Apriori-based
algorithm, second on Breadth First Search-based strategy, third on Depth First
Search strategy, fourth on sequential closed-pattern algorithm and five on the
basis of incremental pattern mining algorithms. At the end, a comparative
analysis is done on the basis of important key features supported by various
algorithms. This study gives an enhancement in the understanding of the
approaches of sequential pattern mining.


title: Rough matroids based on coverings

abstract:
  The introduction of covering-based rough sets has made a substantial
contribution to the classical rough sets. However, many vital problems in rough
sets, including attribution reduction, are NP-hard and therefore the algorithms
for solving them are usually greedy. Matroid, as a generalization of linear
independence in vector spaces, it has a variety of applications in many fields
such as algorithm design and combinatorial optimization. An excellent
introduction to the topic of rough matroids is due to Zhu and Wang. On the
basis of their work, we study the rough matroids based on coverings in this
paper. First, we investigate some properties of the definable sets with respect
to a covering. Specifically, it is interesting that the set of all definable
sets with respect to a covering, equipped with the binary relation of inclusion
$\subseteq$, constructs a lattice. Second, we propose the rough matroids based
on coverings, which are a generalization of the rough matroids based on
relations. Finally, some properties of rough matroids based on coverings are
explored. Moreover, an equivalent formulation of rough matroids based on
coverings is presented. These interesting and important results exhibit many
potential connections between rough sets and matroids.


title:
Why robots? A survey on the roles and benefits of social robots in the
  therapy of children with autism

abstract:
  This paper reviews the use of socially interactive robots to assist in the
therapy of children with autism. The extent to which the robots were successful
in helping the children in their social, emotional, and communication deficits
was investigated. Child-robot interactions were scrutinized with respect to the
different target behaviors that are to be elicited from a child during therapy.
These behaviors were thoroughly examined with respect to a childs development
needs. Most importantly, experimental data from the surveyed works were
extracted and analyzed in terms of the target behaviors and how each robot was
used during a therapy session to achieve these behaviors. The study concludes
by categorizing the different therapeutic roles that these robots were observed
to play, and highlights the important design features that enable them to
achieve high levels of effectiveness in autism therapy.


title:
Experimental evidence for direct insulator-quantum Hall transition in
  multi-layer graphene

abstract:
  We have performed magnetotransport measurements on a multi-layer graphene
flake. At the crossing magnetic field Bc, an approximately
temperature-independent point in the measured longitudinal resistivity, which
is ascribed to the direct insulator-quantum Hall (I-QH) transition, is
observed. By analyzing the amplitudes of the magnetoresistivity oscillations,
we are able to measure the quantum mobility of our device. It is found that at
the direct I-QH transition, the product of the quantum mobility and is about
0.37 which is considerably smaller than 1. In contrast, at Bc, the longitudinal
resistivity is close to the Hall resistivity, i.e., the product of the
classical mobility and the crossing field is about 1. Therefore our results
suggest that different mobilities need to be introduced for the direct I-QH
transition observed in multi-layered graphene. Combined with existing
experimental results obtained in various material systems, our data obtained on
graphene suggest that the direct I-QH transition is a universal effect in 2D.


title:
On the Capital Allocation Problem for a New Coherent Risk Measure in
  Collective Risk Theory

abstract:
  In this paper we introduce a new coherent cumulative risk measure on
$\mathcal{R}_L^p$, the space of c\`adl\`ag processes having Laplace transform.
This new coherent risk measure turns out to be tractable enough within a class
of models where the aggregate claims is driven by a spectrally positive L\'evy
process. Moreover, we study the problem of capital allocation in an insurance
context and we show that the capital allocation problem for this risk measure
has a unique solution determined by the Euler allocation method. Some examples
are provided.


title: On symmetric continuum opinion dynamics

abstract:
  This paper investigates the asymptotic behavior of some common opinion
dynamic models in a continuum of agents. We show that as long as the
interactions among the agents are symmetric, the distribution of the agents'
opinion converges. We also investigate whether convergence occurs in a stronger
sense than merely in distribution, namely, whether the opinion of almost every
agent converges. We show that while this is not the case in general, it becomes
true under plausible assumptions on inter-agent interactions, namely that
agents with similar opinions exert a non-negligible pull on each other, or that
the interactions are entirely determined by their opinions via a smooth
function.


title:
Entire solutions for a class of elliptic equations involving
  $p$-biharmonic operator and Rellich potentials

abstract:
  We study existence, multiplicity and qualitative properties of entire
solutions for a noncompact problem related to p-biharmonic type equations with
weights. More precisely, we deal with the following family of equations $$
\Delta_{p}^2 u = \lambda|x|^{-2p}|u|^{p-2}u + |x|^{-\beta}|u|^{q-2}
u\quad\text{in} \quad \mathbb R^N, $$ where $N> 2p$, $p>1$, $q>p$, $\beta = N -
\frac{q}{p}(N-2p)$ and $\lambda\in\mathbb R$ is smaller than the Rellich
constant.


title: Analysis of Quantum Linear Systems' Response to Multi-photon States

abstract:
  The purpose of this paper is to present a mathematical framework for
analyzing the response of quantum linear systems driven by multi-photon states.
Both the factorizable (namely, no correlation among the photons in the channel)
and unfactorizable multi-photon states are treated. Pulse information of
multi-photon input state is encoded in terms of tensor, and response of quantum
linear systems to multi-photon input states is characterized by tensor
operations. Analytic forms of output correlation functions and output states
are derived. The proposed framework is applicable no matter whether the
underlying quantum dynamic system is passive or active. The results presented
here generalize those in the single-photon setting studied in (Milburn, 2008)
and (Zhang and James, 2013}). Moreover, interesting multi-photon interference
phenomena studied in (Sanaka, Resch, and Zeilinger, 2006), (Ou, 2007), and
(Bartley, et al., 2012) can be reproduced in the proposed framework


title: A Faster Algorithm to Recognize Even-Hole-Free Graphs

abstract:
  We study the problem of determining whether an $n$-node graph $G$ has an even
hole, i.e., an induced simple cycle consisting of an even number of nodes.
Conforti, Cornu\'ejols, Kapoor, and Vu\v{s}kovi\'c gave the first
polynomial-time algorithm for the problem, which runs in $O(n^{40})$ time.
Later, Chudnovsky, Kawarabayashi, and Seymour reduced the running time to
$O(n^{31})$. The best previously known algorithm for the problem, due to da
Silva and Vu\v{s}kovi\'c, runs in $O(n^{19})$ time. In this paper, we solve the
problem in $O(n^{11})$ time. Moreover, if $G$ has even holes, our algorithm
also outputs an even hole of $G$ in $O(n^{11})$ time.


title:
Optimizing data collection for object tracking in wireless sensor
  networks

abstract:
  In this paper some modifications are proposed to optimize an algorithm of
object tracking in wireless sensor network (WSN). The task under consideration
is to control movement of a mobile sink, which has to reach a target in the
shortest possible time. Utilization of the WSN resources is optimized by
transferring only selected data readings (target locations) to the mobile sink.
Simulations were performed to evaluate the proposed modifications against
state-of-the-art methods. The obtained results show that the presented tracking
algorithm allows for substantial reduction of data collection costs with no
significant increase in the amount of time that it takes to catch the target.


title: Multivariate Generalized Gaussian Process Models

abstract:
  We propose a family of multivariate Gaussian process models for correlated
outputs, based on assuming that the likelihood function takes the generic form
of the multivariate exponential family distribution (EFD). We denote this model
as a multivariate generalized Gaussian process model, and derive Taylor and
Laplace algorithms for approximate inference on the generic model. By
instantiating the EFD with specific parameter functions, we obtain two novel GP
models (and corresponding inference algorithms) for correlated outputs: 1) a
Von-Mises GP for angle regression; and 2) a Dirichlet GP for regressing on the
multinomial simplex.


title: Quantization In Finite Volumes Using Symplectic Quantization Programm

abstract:
  We use the ideas of symplectic quantization for quantizing fields in finite
volumes. We consider, as examples, the Klein-Gordon and electromagnetic fields
in three dif- ferent boxes. As a second idea we consider the given boundary
conditions as primary constrains. Consistency of primary constrains leads to
infinite chains of constraints at the boundaries. Without solving the equation
of motion, we impose the set of con- straints on suitable expansions of the
fields. We show that if the new set of variables, such as Fourier modes, are
chosen appropriately, imposing the constraints omits a few number of canonical
pairs. Hence, the reduced phase space, with canonical pairs as coordinates, is
achieved.


title:
A Linear-Time and Space Algorithm for Optimal Traffic Signal Durations
  at an Intersection

abstract:
  Finding an optimal solution of signal traffic control durations is a
computationally intensive task. It is typically O(T3) in time, and O(T2) in
space, where T is the length of the control interval in discrete time steps. In
this paper, we propose a linear time and space algorithm for the same problem.
The algorithm provides for an efficient dynamic programming formulation of the
state space, the prunes non-optimal states, early on. The paper proves the
correctness of the algorithm and provides an initial experimental validation.


title: About the range property for H

abstract:
  Recently, A. Polonsky has shown that the range property fails for H. We give
here some conditions on a closed term that imply that its range has an infinite
cardinality.


title:
Numerical method for hyperbolic conservation laws via forward backward
  SDEs

abstract:
  It is well known that for solutions of semi-linear parabolic PDEs, there are
equivalent probabilistic interpretations, which yields the so called nonlinear
Feymman-Kac formula. By adopting such formula, we consider in this work a novel
numerical approach for solutions of hyperbolic conservation laws. Our numerical
method consists in efficiently computing the viscosity solutions of
conservation laws. However, instead of solving the viscosity problem directly
(which is difficult), we find its equivalent probabilistic solution by adopting
the Feymman-Kac formula, which relies on solving the equivalent forward
backward stochastic differential equations. It is noticed that such framework
possesses the following advantages: (i) the viscosity parameter can be chosen
sufficiently small (say $10^{-10}$); (ii) the computational procedure on each
discretized time level can be \textit{completely parallel}; (iii) the
traditional CFL condition is dramatically weakened; (iv) one does not need to
handle the transition layers and discertizations of derivatives. Thus, high
accuracy viscosity solutions can be efficiently found. Several numerical
examples are given to demonstrate the effectiveness of the proposed numerical
method.


title:
Plancherel-Rotach formulae for average characteristic polynomials of
  products of Ginibre random matrices and the Fuss-Catalan distribution

abstract:
  Formulae of Plancherel-Rotach type are established for the average
characteristic polynomials of certain Hermitian products of rectangular Ginibre
random matrices on the region of zeros. These polynomials form a general class
of multiple orthogonal hypergeometric polynomials generalizing the classical
Laguerre polynomials. The proofs are based on a multivariate version of the
complex method of saddle points. After suitable rescaling the asymptotic zero
distributions for the polynomials are studied and shown to coincide with the
Fuss-Catalan distributions. Moreover, introducing appropriate coordinates,
elementary and explicit characterizations are derived for the densities as well
as for the distribution functions of the Fuss-Catalan distributions of general
order.


title: On the Lattice Isomorphism Problem

abstract:
  We study the Lattice Isomorphism Problem (LIP), in which given two lattices
L_1 and L_2 the goal is to decide whether there exists an orthogonal linear
transformation mapping L_1 to L_2. Our main result is an algorithm for this
problem running in time n^{O(n)} times a polynomial in the input size, where n
is the rank of the input lattices. A crucial component is a new generalized
isolation lemma, which can isolate n linearly independent vectors in a given
subset of Z^n and might be useful elsewhere. We also prove that LIP lies in the
complexity class SZK.


title:
A new approach to pointwise heat kernel upper bounds on doubling metric
  measure spaces

abstract:
  On doubling metric measure spaces endowed with a strongly local regular
Dirichlet form, we show some characterisations of pointwise upper bounds of the
heat kernel in terms of global scale-invariant inequalities that correspond
respectively to the Nash inequality and to a Gagliardo-Nirenberg type
inequality when the volume growth is polynomial. This yields a new proof and a
generalisation of the well-known equivalence between classical heat kernel
upper bounds and relative Faber-Krahn inequalities or localized Sobolev or Nash
inequalities. We are able to treat more general pointwise estimates, where the
heat kernel rate of decay is not necessarily governed by the volume growth. A
crucial role is played by the finite propagation speed property for the
associated wave equation, and our main result holds for an abstract semigroup
of operators satisfying the Davies-Gaffney estimates.


title:
High precision $^{113}$In($\alpha,\alpha$)$^{113}$In elastic scattering
  at energies around the Coulomb barrier for the astrophysical $\gamma$ process

abstract:
  The $\gamma$ process in supernova explosions is thought to explain the origin
of proton-rich isotopes between Se and Hg, the so-called $p$ nuclei. The
majority of the reaction rates for $\gamma$ process reaction network studies
has to be predicted in Hauser-Feshbach statistical model calculations using
global optical potential parameterizations. While the nucleon+nucleus optical
potential is fairly known, for the $\alpha$+nucleus optical potential several
different parameterizations exist and large deviations are found between the
predictions calculated using different parameter sets. By the measurement of
elastic $\alpha$-scattering angular distributions at energies around the
Coulomb barrier a comprehensive test for the different global $\alpha$+nucleus
optical potential parameter sets is provided. Between 20$^{\circ}$ and
175$^{\circ}$ complete elastic alpha scattering angular distributions were
measured on the $^{113}$In \textit{p} nucleus with high precision at E$_{c.m.}$
= 15.59 and 18.82 MeV. The elastic scattering cross sections of the
$^{113}$In($\alpha$,$\alpha$)$^{113}$In reaction were measured for the first
time at energies close to the astrophysically relevant energy region. The high
precision experimental data were used to evaluate the predictions of the recent
global and regional $\alpha$+nucleus optical potentials. Parameters for a local
$\alpha$+nucleus optical potential were derived from the measured angular
distributions. Predictions for the reaction cross sections of
$^{113}$In($\alpha,\gamma$)$^{117}$Sb and $^{113}$In($\alpha$,n)$^{116}$Sb at
astrophysically relevant energies were given using the global and local optical
potential parameterizations.


title:
Stimulation of a Singlet Superconductivity in SFS Weak Links by
  Spin-Exchange Scattering of Cooper Pairs

abstract:
  Josephson junctions with a ferromagnetic metal weak link reveal a very strong
decrease of the critical current compared to a normal metal weak link. We
demonstrate that in the ballistic regime the presence of a small region with a
non-collinear magnetization near the center of a ferromagnetic weak link
restores the critical current inherent to the normal metal. The above effect
can be stimulated by additional electrical bias of the magnetic gate which
induces a local electron depletion of ferromagnetic barrier. The underlying
physics of the effect is the interference phenomena due to the magnetic
scattering of the Cooper pair, which reverses its total momentum in the
ferromagnet and thus compensates the phase gain before and after the
spin-reversed scattering. In contrast with the widely discussed triplet long
ranged proximity effect we elucidate a new singlet long ranged proximity
effect. This phenomenon opens a way to easily control the properties of SFS
junctions and inversely to manipulate the magnetic moment via the Josephson
current.


title:
Radiative corrections for electron proton elastic scattering taking into
  account high orders and hard photon emission

abstract:
  We investigate the effect of high order radiative corrections in unpolarized
electron proton elastic scattering and compare with the calculations at lowest
order, which are usually applied to experimental data. Particular attention is
devoted to the $\epsilon$ dependence of radiative corrections, which is
directly related to the electric proton form factor. We consider in particular
the effects of the interference terms for soft and hard photon emission. Both
quadratic amplitude describing the collinear emission along the scattered
electron as well as the interference with the amplitudes of emission from the
initial electron and the emission from protons are important in leading and
next to leading approximation and they may compensate in particular kinematical
conditions.


title:
Low-energy structure and anti-bubble effect of dynamical correlations in
  46Ar

abstract:
  The low-energy structure of 46Ar is of particular interest due to the
possible coexistence of different shapes and the possible existence of proton
bubble structure. In this work, we apply a beyond relativistic mean-field
approach to study the low-energy structure of 46Ar. Correlations beyond the
mean field are introduced by configuration mixing of both particle-number and
angular-momentum projected axially deformed mean-field states. The low-lying
spectroscopy and charge density in laboratory frame are calculated and an
excellent agreement with available data is achieved. Even though an evident
proton bubble structure is shown in the spherical state of 46Ar, it eventually
disappears after taking into account the dynamical correlation effects.
Moreover, our results indicate that the existence of proton bubble structure in
argon isotopes is unlikely.


title:
Quadratic differentials and asymptotics of Laguerre polynomials with
  varying complex parameters

abstract:
  In this paper we study the asymptotics (as $n\to \infty$) of the sequences of
Laguerre polynomials with varying complex parameters $\alpha$ depending on the
degree $n$. More precisely, we assume that $\alpha_n = n A_n, $ and $ \lim_n
A_n=A \in \mathbb{C}$. This study has been carried out previously only for
$\alpha_n\in \mathbb{R}$, but complex values of $A$ introduce an asymmetry that
makes the problem more difficult.
  The main ingredient of the asymptotic analysis is the right choice of the
contour of orthogonality, which requires the analysis of the global structure
of trajectories of an associated quadratic differential on the complex plane,
which may have an independent interest.
  While the weak asymptotics is obtained by reduction to the theorem of
Gonchar--Rakhmanov--Stahl, the strong asymptotic results are derived via the
non-commutative steepest descent analysis based on the Riemann-Hilbert
characterization of the Laguerre polynomials.


title:
Growth of ZnO nanolayers inside the capillaries of photonic crystal
  fibres

abstract:
  In this study, we describe the formation of ZnO nanolayers inside the air
capillaries of a silica photonic crystal fibre (PCF), targeting random laser
and organic vapor sensing applications. ZnO nanolayers were developed by
infiltrating the capillaries of the silica PCF with Zn-acetate/methanol
solutions of various concentrations, followed by annealing treatments. The
growth and morphology of the synthesized ZnO nanolayers were characterized by
means of scanning electron microscopy (SEM) and found to be affected by the
concentration of the Zn-acetate/methanol infiltration solution. For low
concentrations, inspection with SEM revealed the formation of 25 and
100-nm-thick ZnO nanolayers across the entire length of the infiltrated
capillaries, whereas increasing the Zn-acetate concentration resulted to the
formation of randomly placed isolated ZnO nanorods. Room temperature
photoluminescence spectra of the ZnO nanolayers inside the PCF were measured
and compared with the corresponding spectra reported for ZnO structures formed
on typical surfaces.


title: Low-Frequency Quantum Oscillations due to Strong Electron Correlations

abstract:
  The normal-state energy spectrum of the two-dimensional $t$-$J$ model in a
homogeneous perpendicular magnetic field is investigated. The density of states
at the Fermi level as a function of the inverse magnetic field $\frac{1}{B}$
reveals oscillations in the range of hole concentrations $0.08<x<0.18$. The
oscillations have both high- and low-frequency components. The former
components are connected with large Fermi surfaces, while the latter with van
Hove singularities in the Landau subbands, which traverse the Fermi level with
changing $B$. The singularities are related to bending the Landau subbands due
to strong electron correlations. Frequencies of these components are of the
same order of magnitude as quantum oscillation frequencies observed in
underdoped cuprates.


title:
Estimates for norms of two-weighted summation operators on a tree under
  some conditions on weights

abstract:
  Two-side estimates for two-weighted discrete Hardy-type operators on a tree
are obtained. For general weights we prove the discrete analogue of Evans -
Harris - Pick theorem (it is a quite simple consequence from their result). It
gives the order estimate for the norm of the weighted summation operator, but
this estimate is rather complicated. Under some conditions on weights, we
obtain estimates which are more simple and convenient for applications.


title: On the Bootstrap for Persistence Diagrams and Landscapes

abstract:
  Persistent homology probes topological properties from point clouds and
functions. By looking at multiple scales simultaneously, one can record the
births and deaths of topological features as the scale varies. In this paper we
use a statistical technique, the empirical bootstrap, to separate topological
signal from topological noise. In particular, we derive confidence sets for
persistence diagrams and confidence bands for persistence landscapes.


title:
Coxeter Transformations, the McKay correspondence, and the Slodowy
  correspondence

abstract:
  This talk was presented at Workshop "Spectral Methods in Representation
Theory of Algebras and Applications to the Study of Rings of Singularities",
2008 (Banff, Canada). W. Ebeling established a connection between certain
Poincare series, the Coxeter transformation C, and the corresponding affine
Coxeter transformation C_a (in the context of the McKay correspondence). We
consider the generalized Poincare series [\tilde{P}_G(t)]_0 for the case of
multiply-laced diagrams(in the context of the McKay-Slodowy correspondence) and
extend the Ebeling theorem for this case: [\tilde{P}_G(t)]_0 =
X(t^2)/\tilde{X}(t^2), where X is the characteristic polynomial of the Coxeter
transformation and \tilde{X} is the characteristic polynomial of the
corresponding affine Coxeter transformation. We obtain that Poincare series
coincide for pairs of diagrams obtained by folding: X ({\Gamma}) / X
(\tilde{{\Gamma}}) = X ({\Gamma}^f) / X (\tilde{{\Gamma}}^f), where {\Gamma} is
any (A, D, E type) Dynkin diagram, {\Gamma} is the extended Dynkin diagram, and
the diagrams {\Gamma}^f and \tilde{{\Gamma}}^f are obtained by folding from
{\Gamma} and \tilde{{\Gamma}}, respectively.


title: Comparative Performance Analysis of Intel Xeon Phi, GPU, and CPU

abstract:
  We investigate and characterize the performance of an important class of
operations on GPUs and Many Integrated Core (MIC) architectures. Our work is
motivated by applications that analyze low-dimensional spatial datasets
captured by high resolution sensors, such as image datasets obtained from whole
slide tissue specimens using microscopy image scanners. We identify the data
access and computation patterns of operations in object segmentation and
feature computation categories. We systematically implement and evaluate the
performance of these core operations on modern CPUs, GPUs, and MIC systems for
a microscopy image analysis application. Our results show that (1) the data
access pattern and parallelization strategy employed by the operations strongly
affect their performance. While the performance on a MIC of operations that
perform regular data access is comparable or sometimes better than that on a
GPU; (2) GPUs are significantly more efficient than MICs for operations and
algorithms that irregularly access data. This is a result of the low
performance of the latter when it comes to random data access; (3) adequate
coordinated execution on MICs and CPUs using a performance aware task
scheduling strategy improves about 1.29x over a first-come-first-served
strategy. The example application attained an efficiency of 84% in an execution
with of 192 nodes (3072 CPU cores and 192 MICs).


title:
Z_2 indices and factorization properties of odd symmetric Fredholm
  operators

abstract:
  A bounded operator $T$ on a separable, complex Hilbert space is said to be
odd symmetric if $I^*T^tI=T$ where $I$ is a real unitary satisfying $I^2=-1$
and $T^t$ denotes the transpose of $T$. It is proved that such an operator can
always be factorized as $T=I^*A^tIA$ with some operator $A$. This generalizes a
result of Hua and Siegel for matrices. As application it is proved that the set
of odd symmetric Fredholm operators has two connected components labelled by a
$Z_2$-index given by the parity of the dimension of the kernel of $T$. This
recovers a result of Atiyah and Singer. Two examples of $Z_2$-valued index
theorems are provided, one being a version of the Noether-Gohberg-Krein theorem
with symmetries and the other an application to topological insulators.


title: Many-core applications to online track reconstruction in HEP experiments

abstract:
  Interest in parallel architectures applied to real time selections is growing
in High Energy Physics (HEP) experiments. In this paper we describe performance
measurements of Graphic Processing Units (GPUs) and Intel Many Integrated Core
architecture (MIC) when applied to a typical HEP online task: the selection of
events based on the trajectories of charged particles. We use as benchmark a
scaled-up version of the algorithm used at CDF experiment at Tevatron for
online track reconstruction - the SVT algorithm - as a realistic test-case for
low-latency trigger systems using new computing architectures for LHC
experiment. We examine the complexity/performance trade-off in porting existing
serial algorithms to many-core devices. Measurements of both data processing
and data transfer latency are shown, considering different I/O strategies
to/from the parallel devices.


title: On Products of Generalized Geometries

abstract:
  In this paper we address what generalized geometric structures are possible
on products of spaces that each admit generalized geometries. In particular we
consider, first, the product of two odd dimensional spaces that each admit a
generalized almost contact structure, and then subsequently, the product of an
odd dimensional space that admits a generalized almost contact structure and an
even dimensional space that admits a generalized almost complex structure. We
also draw attention to the relationship of the Courant bracket to the classical
notion of normality for almost contact structures.


title:
Stretching and folding processes in the 3D Euler and Navier-Stokes
  equations

abstract:
  Stretching and folding dynamics in the incompressible, stratified 3D Euler
and Navier-Stokes equations are reviewed in the context of the vector $\bdB =
\nabla q\times\nabla\theta$ where $q=\bom\cdot\nabla\theta$. The variable
$\theta$ is the temperature and $\bdB$ satisfies $\partial_{t}\bdB =
\mbox{curl}\,(\bu\times\bdB)$. These ideas are then discussed in the context of
the full compressible Navier-Stokes equations where $q$ takes the two forms $q
= \bom\cdot\nabla\rho$ and $q = \bom\cdot\nabla(\ln\rho)$.


title:
Multi-Wavelength Observations of PKS 2142-75 during Active and Quiescent
  Gamma-Ray States

abstract:
  PKS2142-75 (a.k.a. 2FGL J2147.4-7534) is a flat-spectrum radio quasar that
was observed quasi-simultaneously by a suite of instruments across the elec-
tromagnetic spectrum during two flaring states in April 2010 and August 2011 as
well as a quiescent state in December 2011 through January 2012. The results of
these campaigns and model spectral energy distributions (SEDs) from the active
and quiescent states are presented. The SED model parameters of PKS 2142-75
indicate that the two flares of the source are created by unique physical
conditions. SED studies of flat spectrum radio quasars are beginning to
indicate that there might be two types of flares, those that can be described
purely by changes in the electron distribution and those that require changes
in other parameters, such as the magnetic field strength or the size of the
emitting region.


title: Transformation optics with Fabry-P\'erot resonances

abstract:
  Transformation optics is a powerful tool to design various novel devices,
such as invisibility cloak. Fantastic effects from this technique are usually
accompanied with singular mappings, resulting in challenging implementations
and narrow bands of working frequencies. Here in this article, we find that
Fabry-P\'erot resonances can be used to design various transformation optical
devices that are not only easy to realize but also can work well for a set of
resonant frequencies (multiple frequencies). As an example, we fabricate a
prototype for a cylindrical concentrator for microwaves.


title: Accretion of multi-species plasma onto black holes

abstract:
  Matter falling onto a black hole is trans-relativistic, transonic, and close
to the horizon it is sub-Keplerian. Such a flow shows the existence of multiple
critical point, shocks etc. Employing relativistic equation of state and
realistic composition, it has been shown that the solution strongly depend on
the composition of the fluid. Electron-positron fluid is the least
relativistic, to the extent that multiple critical points, shocks etc do not
form. The most relativistic fluid is the one whose ratio of proton to electron
number density is ~ 0.2. Since the solution strongly depend on composition, the
emitted radiation should strongly depend on the composition too.


title:
FDTD analysis of photonic quasicrystals with different tiling geometries
  and fabrication by single beam computer-generated holography

abstract:
  Multiple-beam holography has been widely used for the realization of photonic
quasicrystals with high rotational symmetries not achievable by the
conventional periodic crystals. Accurate control of the properties of the
interfering beams is necessary to provide photonic band-gap structures. Here we
show, by FDTD simulations of the transmission spectra of 8-fold quasiperiodic
structures, how the geometric tiling of the structure affects the presence and
properties of the photonic band-gap for low refractive index contrasts. Hence,
we show an interesting approach to the fabrication of photonic quasicrystals
based on the use of a programmable Spatial Light Modulator encoding
Computer-Generated Holograms, that permits an accurate control of the writing
pattern with almost no limitations in the pattern design. Using this
single-beam technique we fabricated quasiperiodic structures with high
rotational symmetries and different geometries of the tiling, demonstrating the
great versatility of our technique.


title: The shape of $\mathbb{Z}/\ell\mathbb{Z}$-number fields

abstract:
  Let $\ell$ be a prime and let $L/\mathbb{Q}$ be a Galois number field with
Galois group isomorphic to $\mathbb{Z}/\ell\mathbb{Z}$. We show that the {\it
shape} of $L$ is either $\frac{1}{2}\mathbb{A}_{\ell-1}$ or a fixed sub lattice
depending only on $\ell$; such a dichotomy in the value of the shape only
depends on the type of ramification of $L$. This work is motivated by a result
of Bhargava and Shnidman, and a previous work of the first named author, on the
shape of $\mathbb{Z}/3\mathbb{Z}$ number fields.


title:
Non-linear Task-Space Disturbance Observer for Position Regulation of
  Redundant Robot Arms against Perturbations in 3D Environments

abstract:
  Many day-to-day activities require the dexterous manipulation of a redundant
humanoid arm in complex 3D environments. However, position regulation of such
robot arm systems becomes very difficult in presence of non-linear
uncertainties in the system. Also, perturbations exist due to various unwanted
interactions with obstacles for clumsy environments in which obstacle avoidance
is not possible, and this makes position regulation even more difficult. This
report proposes a non-linear task-space disturbance observer by virtue of which
position regulation of such robotic systems can be achieved in spite of such
perturbations and uncertainties. Simulations are conducted using a 7-DOF
redundant robot arm system to show the effectiveness of the proposed method.
These results are then compared with the case of a conventional mass-damper
based task-space disturbance observer to show the enhancement in performance
using the developed concept. This proposed method is then applied to a
controller which exhibits human-like motion characteristics for reaching a
target. Arbitrary perturbations in the form of interactions with obstacles are
introduced in its path. Results show that the robot end-effector successfully
continues to move in its path of a human-like quasi-straight trajectory even if
the joint trajectories deviated by a considerable amount due to the
perturbations. These results are also compared with that of the unperturbed
motion of the robot which further prove the significance of the developed
scheme.


title: On The Dynamics of a Closed Viscous Universe

abstract:
  We use a dynamical systems approach based on the method of orthonormal frames
to study the dynamics of a non-tilted Bianchi Type IX cosmological model with a
bulk and shear viscous fluid source. We begin by completing a detailed
fix-point analysis which give the local sinks, sources and saddles of the
dynamical system. We then analyze the global dynamics by finding the
$\alpha$-and $\omega$-limit sets which give an idea of the past and future
asymptotic behavior of the system. The fixed points were found to be a flat
Friedmann-LeMa\^{i}tre-Robertson-Walker (FLRW) solution, Bianchi Type $II$
solution, Kasner circle, Jacobs disc, Bianchi Type $VII_{0}$ solutions, and
several closed FLRW solutions in addition to the Einstein static universe
solution. Each equilibrium point was described in both its expanding and
contracting epochs. We conclude the paper with some numerical experiments that
shed light on the global dynamics of the system along with its heteroclinic
orbits. With respect to past asymptotic states, we were able to conclude that
the Jacobs disc in the expanding epoch was a source of the system along with
the flat FLRW solution in a contracting epoch. With respect to future
asymptotic states, we were able to show that the flat FLRW solution in an
expanding epoch along with the Jacobs disc in the contracting epoch were sinks
of the system. We were also able to demonstrate a new result with respect to
the Einstein static universe. Namely, we gave certain conditions on the
parameter space such that the Einstein static universe has an associated stable
subspace. We were however, not able to conclusively say anything about whether
a closed FLRW model could be a past or future asymptotic state of the model.


title: Educating Programmers: A Reflection on Barriers to Deliberate Practice

abstract:
  Programming is a craft which often demands that learners engage in a
significantly high level of individual practice and experimentation in order to
acquire basic competencies. However, practice behaviours can be undermined
during the early stages of instruction. This is often the result of seemingly
trivial misconceptions that, when left unchecked, create cognitive-affective
barriers. These interact with learners' self-beliefs, potentially inducing
affective states that inhibit practice. This paper questions how to design a
learning environment that can address this issue. It is proposed that
analytical and adaptable approaches, which could include soft scaffolding,
ongoing detailed informative feedback and a focus on self-enhancement alongside
skill development, can help overcome such barriers.


title: Deterministic Sequences for Compressive MIMO Channel Estimation

abstract:
  This paper considers the problem of pilot design for compressive
multiple-input multiple-output (MIMO) channel estimation. In particular, we are
interested in estimating the channels for multiple transmitters simultaneously
when the pilot sequences are shorter than the combined channels. Existing works
on this topic demonstrated that tools from compressed sensing theory can yield
accurate multichannel estimation provided that each pilot sequence is randomly
generated. Here, we propose constructing the pilot sequence for each
transmitter from a small set of deterministic sequences. We derive a
theoretical lower bound on the length of the pilot sequences that guarantees
the multichannel estimation with high probability. Simulation results are
provided to demonstrate the performance of the proposed method.


title:
Spectral characterization of two-dimensional Thue-Morse quasicrystals
  realized with high resolution lithography

abstract:
  One-dimensional Thue-Morse (ThMo) lattices are examples of self-similar
structures that exhibit bandgap phenomena. ThMo multilayers may also possess
fractal photonic bandgaps that give rise to large omnidirectional reflectance
and light emission enhancement effects. Two-dimensional (2D) ThMo aperiodic
quasicrystals possess interesting properties for photonic applications too.
Here we demonstrate the experimental fabrication of large area 2D ThMo lattices
into polymeric substrates at nanometer scale by electron beam lithography
(EBL). Far field diffraction patterns of the experimental Thue-Morse structures
have been measured and compared with the calculated theoretical Fourier
spectra. Scanning electron microscopy and far field diffraction are used to
characterize the experimental structures.


title: Fermi LAT and WMAP observations of the supernova remnant HB 21

abstract:
  We present the analysis of Fermi Large Area Telescope (LAT) $\gamma$-ray
observations of HB~21 (G89.0+4.7). We detect significant $\gamma$-ray emission
associated with the remnant: the flux >100 MeV is
$9.4\pm0.8(stat)\pm1.6(syst)\times10^{-11}$ erg cm$^{-2}$ s$^{-1}$. HB 21 is
well modeled by a uniform disk centered at $l= 88{\deg}.75\pm 0{\deg}.04$, $b =
+4{\deg}.65 \pm 0{\deg}.06$ with a radius of $1{\deg}.19 \pm 0{\deg}.06$. The
$\gamma$-ray spectrum shows clear evidence of curvature, suggesting a cutoff or
break in the underlying particle population at an energy of a few GeV. We
complement $\gamma$-ray observations with the analysis of the WMAP 7-year data
from 23 to 93 GHz, achieving the first detection of HB 21 at these frequencies.
In combination with archival radio data, the radio spectrum shows a spectral
break which helps to constrain the relativistic electron spectrum, hence
parameters of simple non-thermal radiation models. In one-zone models
multiwavelength data favor the origin of $\gamma$ rays from nucleon-nucleon
collisions. A single population of electrons cannot produce both $\gamma$ rays
through bremsstrahlung and radio emission through synchrotron radiation. A
predominantly inverse-Compton origin of the $\gamma$-ray emission is disfavored
because it requires lower interstellar densities than are inferred for HB 21.
In the hadronic-dominated scenarios accelerated nuclei contribute a total
energy of $\sim 3 \times10^{49}$ ergs, while in a two-zone
bremsstrahlung-dominated scenario the total energy in accelerated particles is
$\sim1\times10^{49}$ ergs.


title: Computer-Generated Holographic Gratings in Soft Matter

abstract:
  Standard multiple-beam holography has been largely used to produce gratings
in polymer-liquid crystal composites, like POLICRYPS, H-PDLC gratings and
POLIPHEM [1]. In this work we present a different approach to liquid
crystalpolymeric grating production, based on the Computer-Generated Holography
(CGH). The great advantage of using CGH is that interferometer-based schemes
are no longer necessary, avoiding problems related to long term stability of
the interference pattern and multi-beam complex optical setup. Moreover, the
CGH technique allows a wider choice of pattern designs. In this preliminary
work, we obtained promising results, as for instance the patterning of a
square-wave refractive index modulation of a LCpolymeric composite, a pattern
which is not achievable with standard two-beam holography.


title:
Eigenvalue order statistics for random Schr\"odinger operators with
  doubly-exponential tails

abstract:
  We consider random Schr\"odinger operators of the form $\Delta+\xi$, where
$\Delta$ is the lattice Laplacian on $\mathbb Z^d$ and $\xi$ is an i.i.d.
random field, and study the extreme order statistics of the eigenvalues for
this operator restricted to large but finite subsets of $\mathbb Z^d$. We show
that for $\xi$ with a doubly-exponential type of upper tail, the upper extreme
order statistics of the eigenvalues falls into the Gumbel max-order class. The
corresponding eigenfunctions are exponentially localized in regions where $\xi$
takes large, and properly arranged, values. A new and self-contained argument
is thus provided for Anderson localization at the spectral edge which permits a
rather explicit description of the shape of the potential and the
eigenfunctions. Our study serves as an input into the analysis of an associated
parabolic Anderson problem.


title:
Data-based approximate policy iteration for nonlinear continuous-time
  optimal control design

abstract:
  This paper addresses the model-free nonlinear optimal problem with
generalized cost functional, and a data-based reinforcement learning technique
is developed. It is known that the nonlinear optimal control problem relies on
the solution of the Hamilton-Jacobi-Bellman (HJB) equation, which is a
nonlinear partial differential equation that is generally impossible to be
solved analytically. Even worse, most of practical systems are too complicated
to establish their accurate mathematical model. To overcome these difficulties,
we propose a data-based approximate policy iteration (API) method by using real
system data rather than system model. Firstly, a model-free policy iteration
algorithm is derived for constrained optimal control problem and its
convergence is proved, which can learn the solution of HJB equation and optimal
control policy without requiring any knowledge of system mathematical model.
The implementation of the algorithm is based on the thought of actor-critic
structure, where actor and critic neural networks (NNs) are employed to
approximate the control policy and cost function, respectively. To update the
weights of actor and critic NNs, a least-square approach is developed based on
the method of weighted residuals. The whole data-based API method includes two
parts, where the first part is implemented online to collect real system
information, and the second part is conducting offline policy iteration to
learn the solution of HJB equation and the control policy. Then, the data-based
API algorithm is simplified for solving unconstrained optimal control problem
of nonlinear and linear systems. Finally, we test the efficiency of the
data-based API control design method on a simple nonlinear system, and further
apply it to a rotational/translational actuator system. The simulation results
demonstrate the effectiveness of the proposed method.


title:
$L_{10}^r$ From a Combined NNLO Lattice, Continuum Analysis of the Light
  Quark V-A Correlator

abstract:
  A combination of lattice and continuum data for the light-quark V-A
correlator, supplemented by results from a chiral sum-rule analysis of the
flavor-breaking flavor $ud$-$us$ V-A correlator difference, is shown to make
possible a high-precision NNLO determination of the renormalized NLO chiral
low-energy constant $L_{10}^r$. Key to this determination is the ability to
simultaneously fix the two combinations of NNLO low-energy constants also
entering the analysis. With current versions of the strange hadronic $\tau$
branching fractions required as input to the flavor-breaking V-A sum rule, we
find $L_{10}^r(m_\rho ) = -0.00346(29)$. This represents both the best current
precision for $L_{10}^r$, and the first NNLO determination having all errors
under full control.


title:
Applying the $\chi^2$ Regularization Parameter Estimator by Downsampling
  Through Relations with The Singular Value Expansion

abstract:
  The solution, $x$, of the linear system of equations $A x\approx b$ arising
from the discretization of an ill-posed integral equation with a square
integrable kernel $H(s,t)$ is considered. The Tikhonov regularized solution $
x(\lambda)$ is found as the minimizer of $J( x)=\{ \|A x - b\|_2^2 + \lambda^2
\|L x\|_2^2\}$. $ x(\lambda)$ depends on regularization parameter $\lambda$
that trades off the data fidelity, and on the smoothing norm determined by $L$.
Here we consider the case where $L$ is diagonal and invertible, and employ the
Galerkin method to provide the relationship between the singular value
expansion and the singular value decomposition for square integrable kernels.
The resulting approximation of the integral equation permits examination of the
properties of the regularized solution $ x(\lambda)$ independent of the sample
size of the data. We prove that estimation of the regularization parameter can
be obtained by consistently down sampling the data and the system matrix,
leading to solutions of coarse to fine grained resolution. Hence, the estimate
of $\lambda$ for a large problem may be found by downsampling to a smaller
problem, or to a set of smaller problems, effectively moving the costly
estimate of the regularization parameter to the coarse representation of the
problem. Moreover, the full singular value decomposition for the fine scale
system is replaced by a number of dominant terms which is determined from the
coarse resolution system, again reducing the computational cost. Numerical
results illustrate the theory and demonstrate the practicality of the approach
for regularization parameter estimation using generalized cross validation,
unbiased predictive risk estimation and the discrepancy principle applied for
both the system of equations, and the augmented system of equations.


title:
A tractable genotype-phenotype map for the self-assembly of protein
  quaternary structure

abstract:
  The mapping between biological genotypes and phenotypes is central to the
study of biological evolution. Here we introduce a rich, intuitive, and
biologically realistic genotype-phenotype (GP) map, that serves as a model of
self-assembling biological structures, such as protein complexes, and remains
computationally and analytically tractable. Our GP map arises naturally from
the self-assembly of polyomino structures on a 2D lattice and exhibits a number
of properties: $\textit{redundancy}$ (genotypes vastly outnumber phenotypes),
$\textit{phenotype bias}$ (genotypic redundancy varies greatly between
phenotypes), $\textit{genotype component disconnectivity}$ (phenotypes consist
of disconnected mutational networks) and $\textit{shape space covering}$ (most
phenotypes can be reached in a small number of mutations). We also show that
the mutational robustness of phenotypes scales very roughly logarithmically
with phenotype redundancy and is positively correlated with phenotypic
evolvability. Although our GP map describes the assembly of disconnected
objects, it shares many properties with other popular GP maps for connected
units, such as models for RNA secondary structure or the HP lattice model for
protein tertiary structure. The remarkable fact that these important properties
similarly emerge from such different models suggests the possibility that
universal features underlie a much wider class of biologically realistic GP
maps.


title: Some properties of the Riesz potentials in Dunkl analysis

abstract:
  In Dunkl theory on Rd which generalizes classical Fourier analysis, we study
first the behavior at infinity of the Riesz potential of a non compactly
supported function. Second, we give for 1<p<=q<infinite, weighted (Lp,Lq)
boundedness of the Riesz potentials with sufficient conditions. As application,
we prove a weighted generalized Sobolev inequality.


title: Topological Conjugacy of Real Projective Flows

abstract:
  In this paper we prove the following topological classification result for
flows on real projective space induced by linear flows on Euclidean space: Two
flows on the projective space P(V) of a finite-dimensional real vector space V,
induced by endomorphisms A and B of V, are topologically conjugate if and only
if the Jordan structures of A and B coincide except for the real parts of the
eigenvalues whose values may differ but whose order and multiplicities must
agree. Our proof is mainly based on ideas of Kuiper who considered the
discrete-time analogue of this classification problem. We also correct a
mistake in Kuiper's proof.


title:
Accelerating Dissipative Particle Dynamics Simulations on GPUs:
  Algorithms, Numerics and Applications

abstract:
  We present a scalable dissipative particle dynamics simulation code, fully
implemented on the Graphics Processing Units (GPUs) using a hybrid CUDA/MPI
programming model, which achieves 10-30 times speedup on a single GPU over 16
CPU cores and almost linear weak scaling across a thousand nodes. A unified
framework is developed within which the efficient generation of the neighbor
list and maintaining particle data locality are addressed. Our algorithm
generates strictly ordered neighbor lists in parallel, while the construction
is deterministic and makes no use of atomic operations or sorting. Such
neighbor list leads to optimal data loading efficiency when combined with a
two-level particle reordering scheme. A faster in situ generation scheme for
Gaussian random numbers is proposed using precomputed binary signatures. We
designed custom transcendental functions that are fast and accurate for
evaluating the pairwise interaction. The correctness and accuracy of the code
is verified through a set of test cases simulating Poiseuille flow and
spontaneous vesicle formation. Computer benchmarks demonstrate the speedup of
our implementation over the CPU implementation as well as strong and weak
scalability. A large-scale simulation of spontaneous vesicle formation
consisting of 128 million particles was conducted to further illustrate the
practicality of our code in real-world applications.


title:
Noisy Quantum Cellular Automata for Quantum vs Classical Excitation
  Transfer

abstract:
  We introduce a class of noisy quantum cellular automata on a qubit lattice
that includes all classical Markov chains, as well as maps where quantum
coherence between sites is allowed to build up over time. We apply such a
construction to the problem of excitation transfer through 1-d lattices, and
compare the performance of classical and quantum dynamics with equal local
transition probabilities. Our discrete approach has the merits of stripping
down the complications of the open system dynamics, of clearly isolating
coherent effects, of allowing for an exact treatment of conditional dynamics,
all while capturing a rich variety of dynamical behaviours.


title:
Physical-Layer Security with Multiuser Scheduling in Cognitive Radio
  Networks

abstract:
  In this paper, we consider a cognitive radio network that consists of one
cognitive base station (CBS) and multiple cognitive users (CUs) in the presence
of multiple eavesdroppers, where CUs transmit their data packets to CBS under a
primary user's quality of service (QoS) constraint while the eavesdroppers
attempt to intercept the cognitive transmissions from CUs to CBS. We
investigate the physical-layer security against eavesdropping attacks in the
cognitive radio network and propose the user scheduling scheme to achieve
multiuser diversity for improving the security level of cognitive transmissions
with a primary QoS constraint. Specifically, a cognitive user (CU) that
satisfies the primary QoS requirement and maximizes the achievable secrecy rate
of cognitive transmissions is scheduled to transmit its data packet. For the
comparison purpose, we also examine the traditional multiuser scheduling and
the artificial noise schemes. We analyze the achievable secrecy rate and
intercept probability of the traditional and proposed multiuser scheduling
schemes as well as the artificial noise scheme in Rayleigh fading environments.
Numerical results show that given a primary QoS constraint, the proposed
multiuser scheduling scheme generally outperforms the traditional multiuser
scheduling and the artificial noise schemes in terms of the achievable secrecy
rate and intercept probability. In addition, we derive the diversity order of
the proposed multiuser scheduling scheme through an asymptotic intercept
probability analysis and prove that the full diversity is obtained by using the
proposed multiuser scheduling.


title:
Schr\"odinger functional boundary conditions and improvement of the
  SU($N$) pure gauge action for $N>3$

abstract:
  The leading method to study the running coupling constant of non-abelian
gauge theories is based on the Schr\"odinger functional scheme. However, the
boundary conditions and $\mathcal{O}(a)$ improvement have not been
systematically generalized for theories with more than three colors. These
theories have applications in BSM model building as well as in the large $N$
limit. We have studied the boundary conditions and improvement for the pure
Yang-Mills theory within the Schr\"odinger functional scheme. We have
determined for all values of $N$ the boundary fields which provide high
signal/noise ratio. Additionally, we have calculated the improvement
coefficient $c_t$ for the pure gauge to one loop order for SU($N$) gauge
theories with $N=2,\ldots,8$ from which $N\geq 4$ are previously unknown.


title: Quantum-ring spin interference device tuned by quantum point contacts

abstract:
  We introduce a spin-interference device that comprises a quantum ring (QR)
with three embedded quantum point contacts (QPCs) and study theoretically its
spin transport properties in the presence of Rashba spin-orbit interaction. Two
of the QPCs conform the lead-to-ring junctions while a third one is placed
symmetrically in the upper arm of the QR. Using an appropriate scattering model
for the QPCs and the $\mathbb{S}$-matrix scattering approach, we analyze the
role of the QPCs on the Aharonov-Bohm (AB) and Aharonov-Casher (AC) conductance
oscillations of the QR-device. Exact formulas are obtained for the
spin-resolved conductances of the QR-device as a function of the confinement of
the QPCs and the AB/AC phases. Conditions for the appearance of resonances and
anti-resonances in the spin-conductance are derived and discussed. We predict
very distinctive variations of the QR-conductance oscillations not seen in
previous QR proposals. In particular we find that the interference pattern in
the QR can be manipulated to a large extend by varying electrically the
lead-to-ring topological parameters. The latter can be used to modulate the AB
and AC phases by applying gate voltage only. We have shown also that the
conductance oscillations exhibits a crossover to well-defined resonances as the
lateral QPC confinement strength is increased, mapping the eigenenergies of the
QR. In addition, unique features of the conductance arises by varying the
aperture of the upper-arm QPC and the Rashba spin-orbit coupling. Our results
may be of relevance for promising spin-orbitonics devices based in quantum
interference mechanisms.


title: Audio Texture Synthesis with Scattering Moments

abstract:
  We introduce an audio texture synthesis algorithm based on scattering
moments. A scattering transform is computed by iteratively decomposing a signal
with complex wavelet filter banks and computing their amplitude envelop.
Scattering moments provide general representations of stationary processes
computed as expected values of scattering coefficients. They are estimated with
low variance estimators from single realizations. Audio signals having
prescribed scattering moments are synthesized with a gradient descent
algorithms. Audio synthesis examples show that scattering representation
provide good synthesis of audio textures with much fewer coefficients than the
state of the art.


title: Evolution of the Magnetic Field Structure of the Crab Pulsar

abstract:
  Pulsars are highly-magnetised rotating neutron stars and are well-known for
the stability of their signature pulse shapes, allowing high-precision studies
of their rotation. However, during the past 22 years, the radio pulse profile
of the Crab pulsar has shown a steady increase in the separation of the main
pulse and interpulse components at 0.62$^{\rm o}\pm$0.03$^{\rm o}$ per century.
There are also secular changes in the relative strengths of several components
of the profile. The changing component separation indicates that the axis of
the dipolar magnetic field, embedded in the neutron star, is moving towards the
stellar equator. This evolution of the magnetic field could explain why the
pulsar does not spin down as expected from simple braking by a rotating dipolar
magnetic field.


title:
The influence of the radiative non-symmetric ion-atom collisions on the
  stellar atmospheres in VUV region

abstract:
  The aim of this work is to draw attention to the processes of radiative
charge exchange in non-symmetric ion-atom collisions as a factor of influence
on the opacity of stellar atmospheres in VUV region. For that purpose
calculations of the spectral absorption coefficients for several ion-atom
systems, namely: He + H$^{+}$ and H + X$^{+}$, where X = Na and Li have been
performed. On chosen examples it has been established that the examined
processes generate rather wide molecular absorption bands in the VUV region,
which should be taken into account for the interpretation of data obtained from
laboratory measurements or astrophysical observations. In this paper the
potential significance is discussed of the considered radiative processes for
DB white dwarfs and solar atmospheres, as well as for the atmospheres of the
so-called lithium stars.


title: The moment-weight inequality and the Hilbert-Mumford criterion

abstract:
  This paper gives an essentially self-contained exposition (except for an
appeal to the Lojasiewicz gradient inequality) of geometric invariant theory
from a differential geometric viewpoint. Central ingredients are the
moment-weight inequality (relating the Mumford numerical invariants to the norm
of the moment map), the negative gradient flow of the moment map squared, and
the Kempf-Ness function.


title:
A pattern-forming instability co-driven by distinct mechanisms increases
  pattern diversity

abstract:
  We use the context of dryland vegetation to study a general problem of
complex pattern forming systems - multiple pattern-forming instabilities that
are driven by distinct mechanisms but share the same spectral properties. We
find that the co-occurrence of such instabilities results in the growth of a
single mode rather than two interacting modes. The interplay between the two
mechanisms, which promote or counteract each other, compensates for the simpler
dynamics of a single mode by inducing higher pattern diversity. Possible
implications to biodiversity of ecosystems are discussed.


title:
Optimal Uniform Convergence Rates for Sieve Nonparametric Instrumental
  Variables Regression

abstract:
  We study the problem of nonparametric regression when the regressor is
endogenous, which is an important nonparametric instrumental variables (NPIV)
regression in econometrics and a difficult ill-posed inverse problem with
unknown operator in statistics. We first establish a general upper bound on the
sup-norm (uniform) convergence rate of a sieve estimator, allowing for
endogenous regressors and weakly dependent data. This result leads to the
optimal sup-norm convergence rates for spline and wavelet least squares
regression estimators under weakly dependent data and heavy-tailed error terms.
This upper bound also yields the sup-norm convergence rates for sieve NPIV
estimators under i.i.d. data: the rates coincide with the known optimal
$L^2$-norm rates for severely ill-posed problems, and are power of $\log(n)$
slower than the optimal $L^2$-norm rates for mildly ill-posed problems. We then
establish the minimax risk lower bound in sup-norm loss, which coincides with
our upper bounds on sup-norm rates for the spline and wavelet sieve NPIV
estimators. This sup-norm rate optimality provides another justification for
the wide application of sieve NPIV estimators. Useful results on
weakly-dependent random matrices are also provided.


title: Information, Computation, Cognition. Agency-based Hierarchies of Levels

abstract:
  Nature can be seen as informational structure with computational dynamics
(info-computationalism), where an (info-computational) agent is needed for the
potential information of the world to actualize. Starting from the definition
of information as the difference in one physical system that makes a difference
in another physical system, which combines Bateson and Hewitt definitions, the
argument is advanced for natural computation as a computational model of the
dynamics of the physical world where information processing is constantly going
on, on a variety of levels of organization. This setting helps elucidating the
relationships between computation, information, agency and cognition, within
the common conceptual framework, which has special relevance for biology and
robotics.


title: On Agents and Equilibria

abstract:
  This essay discusses the advantages of a probabilistic agent-based approach
to questions in theoretical economics, from the nature of economic agents, to
the nature of the equilibria supported by their interactions. One idea we
propose is that "agents" are meta-individual, hierarchically structured
objects, that include as irreducible components groupings of different
dimensions. We also explore the effects of non-ergodicity, by constructing a
simple stochastic model for the contingent nature of economic interactions.


title:
Performance enhancement of TiO2-based dye-sensitized solar cells by
  carbon nanospheres in photoanode

abstract:
  The conversion efficiency of dye-sensitized solar cells (DSSCs) is optimized
by modifying the optical design and improving absorbance within the cell. These
objectives are obtained by creating different sized cavities in TiO2
photoanode. For this purpose, carbon nanospheres with diameters 100-600 nm are
synthesized by hydrothermal method. A paste of TiO2 is mixed with various
amounts of carbon nanospheres. During TiO2 photoanode sintering processes at
500C temperature, the carbon nanospheres are removed. This leads to random
creation of cavities in the DSSCs photoanode. These cavities enhance light
scattering and porosity which improve light absorbance by dye N719 and provide
a larger surface area for dye loading. These consequences enhance performance
of DSSCs. By mixing 3% Wt. carbon nanospheres in the TiO2 pastes, we were able
to increase the short circuit current density and efficiency by 40% (from 12.59
to 17.73 mA/cm2) and 33% (from 5.72% to 7.59%), respectively.


title:
Structured functional regression models for high-dimensional spatial
  spectroscopy data

abstract:
  Modeling and analysis of spectroscopy data is an active area of research with
applications to chemistry and biology. This paper focuses on analyzing Raman
spectra obtained from a bone fracture healing experiment, although the
functional regression model for predicting a scalar response from
high-dimensional tensors can be applied to any spectroscopy data. The
regression model is built on a sparse functional representation of the spectra,
and accommodates multiple spatial dimensions. We apply our models to the task
of predicting bone-mineral-density (BMD), an important indicator of fracture
healing, from Raman spectra, in both the in vivo and ex vivo settings of the
bone fracture healing experiment. To illustrate the general applicability of
the method, we also use it to predict lipoprotein concentrations from spectra
obtained by nuclear magnetic resonance (NMR) spectroscopy.


title: A particle system with cooperative branching and coalescence

abstract:
  In this paper, we introduce a one-dimensional model of particles performing
independent random walks, where only pairs of particles can produce offspring
("cooperative branching"), and particles that land on an occupied site merge
with the particle present on that site ("coalescence"). We show that the system
undergoes a phase transition as the branching rate is increased. For small
branching rates, the upper invariant law is trivial, and the process started
with finitely many particles a.s. ends up with a single particle. Both
statements are not true for high branching rates. An interesting feature of the
process is that the spectral gap is zero even for low branching rates. Indeed,
if the branching rate is small enough, then we show that for the process
started in the fully occupied state, the particle density decays as one over
the square root of time, and the same is true for the decay of the probability
that the process still has more than one particle at a later time if it started
with two particles.


title:
Measurement of segmental mobility during constant strain rate
  deformation of a poly(methyl methacrylate) glass

abstract:
  We describe an apparatus for performing constant strain rate deformations of
polymer glasses while simultaneously measuring the segmental mobility with an
optical probe reorientation method. Poly(methyl methacrylate) glasses were
deformed at Tg - 19 K, for local strain rates between 3.7x10-5/s and
1.2x10-4/s. In these experiments, the mobility initially increases in the
pre-yield regime, by a factor of 40 to 160, as compared to the undeformed PMMA
glass. The mobility then remains constant after yield, even as the stress is
decreasing due to strain softening. This is consistent with the view that the
sample is being pulled higher on the potential energy landscape in this regime.
Higher strain rates lead to higher mobility in the post-yield regime and, for
the range of strain rates investigated, mobility and strain rate are linearly
correlated. We observe that thermal history has no influence on mobility after
yield and that deformation leads to a narrowing of the distribution of
segmental relaxation times. These last three observations are consistent with
previously reported constant stress experiments on PMMA glasses. The
experimental features reported here are compared to computer simulations and
theoretical models.


title:
The space of K\"ahler potentials on an asymptotically locally euclidean
  K\"ahler manifold

abstract:
  In this note, we shall prove geodesic convexity of the space of K\"ahler
potentials on an ALE K\"ahler manifold. This extends earlier results in the
compact case proved in the fundamental work of X-X. Chen. We further prove the
boundedness from below of the Mabuchi energy, and give an alternative proof for
the uniqueness of scalar-flat metrics in the category of ALE K\"ahler manifold.


title:
TIGER: A data analysis pipeline for testing the strong-field dynamics of
  general relativity with gravitational wave signals from coalescing compact
  binaries

abstract:
  The direct detection of gravitational waves with upcoming second-generation
gravitational wave detectors such as Advanced LIGO and Virgo will allow us to
probe the genuinely strong-field dynamics of general relativity (GR) for the
first time. We present a data analysis pipeline called TIGER (Test
Infrastructure for GEneral Relativity), which is designed to utilize detections
of compact binary coalescences to test GR in this regime. TIGER is a
model-independent test of GR itself, in that it is not necessary to compare
with any specific alternative theory. It performs Bayesian inference on two
hypotheses: the GR hypothesis $\mathcal{H}_{\rm GR}$, and $\mathcal{H}_{\rm
modGR}$, which states that one or more of the post-Newtonian coefficients in
the waveform are not as predicted by GR. By the use of multiple sub-hypotheses
of $\mathcal{H}_{\rm modGR}$, in each of which a different number of
parameterized deformations of the GR phase are allowed, an arbitrarily large
number of 'testing parameters' can be used without having to worry about a
model being insufficiently parsimonious if the true number of extra parameters
is in fact small. TIGER is well-suited to the regime where most sources have
low signal-to-noise ratios, again through the use of these sub-hypotheses.
Information from multiple sources can trivially be combined, leading to a
stronger test. We focus on binary neutron star coalescences, for which
sufficiently accurate waveform models are available that can be generated fast
enough on a computer to be fit for use in Bayesian inference. We show that the
pipeline is robust against a number of fundamental, astrophysical, and
instrumental effects, such as differences between waveform approximants, a
limited number of post-Newtonian phase contributions being known, the effects
of neutron star spins and tidal deformability on the orbital motion, and
instrumental calibration errors.


title:
A quasi-solution approach to nonlinear problems - the case of Blasius
  similarity solution

abstract:
  Using the simple case of Blasius similarity solution, we illustrate a
recently developed general method that reduces a strongly nonlinear problem
into a weakly nonlinear analysis. The basic idea is to find a quasi-solution
$F_0$ that satisfies the nonlinear problem and boundary conditions to within
small errors. Then, by decomposing the true solution $F=F_0+E$, a weakly
nonlinear analysis of $E$, using contraction mapping theorem in a suitable
space of functions provides the existence of solution as well as bounds on the
error $E$. The quasi-solution construction relies on a combination of
exponential asymptotics and standard orthogonal polynomial representations in
finite domain.


title: On the Sum of Dilations of a Set

abstract:
  We show that for any relatively prime integers $1\leq p<q$ and for any finite
$A \subset \mathbb{Z}$ one has $$|p \cdot A + q \cdot A | \geq (p + q) |A| -
(pq)^{(p+q-3)(p+q) + 1}.$$


title:
Phase Transitions and Cosparse Tomographic Recovery of Compound Solid
  Bodies from Few Projections

abstract:
  We study unique recovery of cosparse signals from limited-angle tomographic
measurements of two- and three-dimensional domains. Admissible signals belong
to the union of subspaces defined by all cosupports of maximal cardinality
$\ell$ with respect to the discrete gradient operator. We relate $\ell$ both to
the number of measurements and to a nullspace condition with respect to the
measurement matrix, so as to achieve unique recovery by linear programming.
These results are supported by comprehensive numerical experiments that show a
high correlation of performance in practice and theoretical predictions.
Despite poor properties of the measurement matrix from the viewpoint of
compressed sensing, the class of uniquely recoverable signals basically seems
large enough to cover practical applications, like contactless quality
inspection of compound solid bodies composed of few materials.


title: Quantifying force networks in particulate systems

abstract:
  We present mathematical models based on persistent homology for analyzing
force distributions in particulate systems. We define three distinct chain
complexes: digital, position, and interaction, motivated by different
capabilities of collecting experimental or numerical data, e.g. digital images,
location of the particles, and normal forces between particles, respectively.
We describe how algebraic topology, in particular, homology allows one to
obtain algebraic representations of the geometry captured by these complexes.
To each complexes we define an associated force network from which persistent
homology is computed. Using numerical data obtained from molecular dynamics
simulations of a system of particles being slowly compressed we demonstrate how
persistent homology can be used to compare the geometries of the force
distributions in different granular systems. We also discuss the properties of
force networks as a function of the underlying complexes, and hence, as a
function of the type of experimental or numerical data provided.


title: Exploration and Research on the New Mixed-Mechanism of Superconductors

abstract:
  We propose a new mixed-mechanism for superconductors, which addresses not
only low- but also high-, and even possible room-temperature superconductivity.
We use this mixed-mechanism to explain superconductivity in different
temperature regions. This new mixed-mechanism is further explored and studied
by investigating the possible interactions that may form Cooper pairs.


title: Towards a coupled-channel optical potential for rare-earth nuclei

abstract:
  We present an outline of an extensive study of the effects of collective
couplings and nuclear deformations on integrated cross sections as well as on
angular distributions in a consistent manner for neutron-induced reactions on
nuclei in the rare-earth region. This specific subset of the nuclide chart was
chosen precisely because of a clear static deformation pattern. We analyze the
convergence of the coupled-channel calculations regarding the number of states
being explicitly coupled. A model for deforming the spherical Koning-Delaroche
optical potential as function of quadrupole and hexadecupole deformations is
also proposed, inspired by previous works. We demonstrate that the obtained
results of calculations for total, elastic, inelastic, and capture cross
sections, as well as elastic and inelastic angular distributions are in
remarkably good agreement with experimental data for scattering energies around
a few MeV.


title: The uniform measure for discrete-time quantum walks in one dimension

abstract:
  We obtain the uniform measure as a stationary measure of the one-dimensional
discrete-time quantum walks by solving the corresponding eigenvalue problem. As
an application, the uniform probability measure on a finite interval at a time
can be given.


title: Bergman Kernel Along The K\"{a}hler Ricci Flow and Tian's Conjecture

abstract:
  In this paper, we study the behavior of Bergman kernels along the K\"{a}hler
Ricci flow on Fano manifolds. We show that the Bergman kernels are equivalent
along the K\"{a}hler Ricci flow under certain condition on the Ricci curvature
of the initial metric. Then, using a recent work of Tian and Zhang, we can
solve a conjecture of Tian for Fano manifolds of complex dimension $\le 3$.


title:
Evaporative cooling of reactive polar molecules confined in a
  two-dimensional geometry

abstract:
  Recent experimental developments in the loading of ultracold KRb molecules
into quasi-two-dimensional traps, combined with the ability to tune the ratio
between elastic and loss (inelastic/reactive) collisions through application of
an external electric field, are opening the door to achieving efficient
evaporative cooling of reactive polar molecules. In this paper, we use Monte
Carlo simulations and semianalytic models to study theoretically the
experimental parameter regimes in which evaporative cooling is feasible under
current trapping conditions. We investigate the effect of the anisotropic
character of dipole-dipole collisions and reduced dimensionality on evaporative
cooling. We also present an analysis of the experimentally relevant
anti-evaporation effects that are induced by chemical reactions that take place
when more than one axial vibrational state is populated.