title: Constructive neural network learning

abstract:
  In this paper, we aim at developing scalable neural network-type learning
systems. Motivated by the idea of "constructive neural networks" in
approximation theory, we focus on "constructing" rather than "training"
feed-forward neural networks (FNNs) for learning, and propose a novel FNNs
learning system called the constructive feed-forward neural network (CFN).
Theoretically, we prove that the proposed method not only overcomes the
classical saturation problem for FNN approximation, but also reaches the
optimal learning rate when the regression function is smooth, while the
state-of-the-art learning rates established for traditional FNNs are only near
optimal (up to a logarithmic factor). A series of numerical simulations are
provided to show the efficiency and feasibility of CFN via comparing with the
well-known regularized least squares (RLS) with Gaussian kernel and extreme
learning machine (ELM).


title: Depreciation and the Time Value of Money

abstract:
  Generally accepted depreciation methods do not compute the intrinsic value of
an asset, as they do not factor for the Time Value of Money, a key principle
within financial theory. This is disadvantageous, as knowing the intrinsic
value of an asset can assist with making effective purchase and sale decisions.
  By applying the Time Value of Money principle to deprecation and book
valuation, methods can be formulated to approximate the intrinsic valuation of
a depreciable asset, which improves the capacity for buyers and sellers of
assets to make rational decisions.
  A deprecation method is formulated within, which aims to better match book
value with intrinsic value. While this method makes many assumptions and thus
has limitations, more complex formulas, which factor for a greater number of
variables, can be created using a similar approach, to produce better
approximations for intrinsic value.


title: Enriched Stone-type dualities

abstract:
  A common feature of many duality results is that the involved equivalence
functors are liftings of hom-functors into the two-element space resp. lattice.
Due to this fact, we can only expect dualities for categories cogenerated by
the two-element set with an appropriate structure. A prime example of such a
situation is Stone's duality theorem for Boolean algebras and Boolean
spaces,the latter being precisely those compact Hausdorff spaces which are
cogenerated by the two-element discrete space. In this paper we aim for a
systematic way of extending this duality theorem to categories including all
compact Hausdorff spaces. To achieve this goal, we combine duality theory and
quantale-enriched category theory. Our main idea is that, when passing from the
two-element discrete space to a cogenerator of the category of compact
Hausdorff spaces, all other involved structures should be substituted by
corresponding enriched versions. Accordingly, we work with the unit interval
$[0,1]$ and present duality theory for ordered and metric compact Hausdorff
spaces and (suitably defined) finitely cocomplete categories enriched in
$[0,1]$.


title:
Indoor Massive MIMO: Uplink Pilot Mitigation Using Channel State
  Information Map

abstract:
  Massive MIMO brings both motivations and challenges to develop the 5th
generation Mobile wireless technology. The promising number of users and the
high bitrate offered per unit area are challenged by uplink pilot contamination
due to pilot reuse and a limited number of orthogonal pilot sequences. This
paper proposes a solution to mitigate uplink pilot contamination in an indoor
scenario where multi-cell share the same pool of pilot sequences, that are
supposed to be less than the number of users. This can be done by reducing
uplink pilots using Channel State Information (CSI) prediction. The proposed
method is based on machine learning approach, where a quantized version of
Channel State Information (QCSI) is learned during estimation session and
stored at the Base Station (BS) to be exploited for future CSI prediction. The
learned QCSI are represented by a weighted directed graph, which is responsible
to monitor and predict the CSI of User Terminals (UTs) in the local cell. We
introduce an online learning algorithm to create and update this graph which we
call CSI map. Simulation results show an increase in the downlink sum-rate and
a significant feedback reduction.


title: Paramagnetically induced gapful topological superconductors

abstract:
  We propose a generic scenario for realizing gapful topological
superconductors (TSCs) from gapless spin-singlet superconductors (SCs).
Noncentrosymmetric nodal SCs in two dimension are shown to be gapful under a
Zeeman field, as a result of the cooperation of inversion-symmetry breaking and
time-reversal-symmetry breaking. In particular, non-s-wave SCs acquire a large
excitation gap. Such paramagnetically-induced gapful SCs may be classified into
TSCs in the symmetry class D specified by the Chern number. We show nontrivial
Chern numbers over a wide parameter range for spin-singlet SCs. A variety of
the paramagnetically-induced gapful TSCs are demonstrated, including D+p-wave
TSC, extended S+p-wave TSC, p+D+f-wave TSC, and s+P-wave TSC. Natural extension
toward three-dimensional Weyl SCs is also discussed.


title:
Effects of aluminum on hydrogen solubility and diffusion in deformed
  Fe-Mn alloys

abstract:
  We discuss hydrogen diffusion and solubility in aluminum alloyed Fe-Mn
alloys. The systems of interest are subjected to tetragonal and isotropic
deformations. Based on ab initio modelling, we calculate solution energies,
then employ Oriani's theory which reflects the influence of Al alloying via
trap site diffusion. This local equilibrium model is complemented by
qualitative considerations of Einstein diffusion. Therefore, we apply the
climbing image nudged elastic band method to compute the minimum energy paths
and energy barriers for hydrogen diffusion. Both for diffusivity and solubility
of hydrogen, we find that the influence of the substitutional Al atom has both
local chemical and nonlocal volumetric contributions.


title:
Usage of Cloud Computing Simulators and Future Systems For Computational
  Research

abstract:
  Cloud Computing is an Internet based computing, whereby shared resources,
software and information, are provided to computers and devices on demand, like
the electricity grid. Currently, IaaS (Infrastructure as a Service), PaaS
(Platform as a Service) and SaaS (Software as a Service) are used as a business
model for Cloud Computing. Nowadays, the adoption and deployment of Cloud
Computing is increasing in various domains, forcing researchers to conduct
research in the area of Cloud Computing globally. Setting up the research
environment is critical for the researchers in the developing countries to
evaluate the research outputs. Currently, modeling, simulation technology and
access of resources from various university data centers has become a useful
and powerful tool in cloud computing research. Several cloud simulators have
been specifically developed by various universities to carry out Cloud
Computing research, including CloudSim, SPECI, Green Cloud and Future Systems
(the Indiana University machines India, Bravo, Delta, Echo and Foxtrot)
supports leading edge data science research and a broad range of
computing-enabled education as well as integration of ideas from cloud and HPC
systems. In this paper, the features, suitability, adaptability and the
learning curve of the existing Cloud Computing simulators and Future Systems
are reviewed and analyzed.


title:
Fractional Brownian motion time-changed by gamma and inverse gamma
  process

abstract:
  Many real time-series exhibit behavior adequate to long range dependent data.
Additionally very often these time-series have constant time periods and also
have characteristics similar to Gaussian processes although they are not
Gaussian. Therefore there is need to consider new classes of systems to model
these kind of empirical behavior. Motivated by this fact in this paper we
analyze two processes which exhibit long range dependence property and have
additional interesting characteristics which may be observed in real phenomena.
Both of them are constructed as the superposition of fractional Brownian motion
(FBM) and other process. In the first case the internal process, which plays
role of the time, is the gamma process while in the second case the internal
process is its inverse. We present in detail their main properties paying main
attention to the long range dependence property. Moreover, we show how to
simulate these processes and estimate their parameters. We propose to use a
novel method based on rescaled modified cumulative distribution function for
estimation of parameters of the second considered process. This method is very
useful in description of rounded data, like waiting times of subordinated
processes delayed by inverse subordinators. By using the Monte Carlo method we
show the effectiveness of proposed estimation procedures.


title:
Generation of nonlocal fractional dynamical systems by fractional
  differential equations

abstract:
  We show that any two trajectories of solutions of a one-dimensional
fractional differential equation (FDE) either coincide or do not intersect each
other. In contrary, in the higher dimensional case, two different trajectories
can meet. Furthermore, one-dimensional FDEs and triangular systems of FDEs
generate nonlocal fractional dynamical systems, whereas a higher dimensional
FDE does, in general, not generate a nonlocal dynamical system.


title: Density of solutions to quadratic congruences

abstract:
  A classical result in number theory is Dirichlet's theorem on the density of
primes in an arithmetic progression. We prove a similar result for numbers with
exactly k prime factors for k>1. Building upon a proof by E.M. Wright in 1954,
we compute the natural density of such numbers where each prime satisfies a
congruence condition. As an application, we obtain the density of squarefree n
not greater than x with k prime factors such that a fixed quadratic equation
has exactly 2^k solutions modulo n.


title: Dynamic Graph Stream Algorithms in $o(n)$ Space

abstract:
  In this paper we study graph problems in dynamic streaming model, where the
input is defined by a sequence of edge insertions and deletions. As many
natural problems require $\Omega(n)$ space, where $n$ is the number of
vertices, existing works mainly focused on designing $\tilde{O}(n)$ space
algorithms. Although sublinear in the number of edges for dense graphs, it
could still be too large for many applications (e.g. $n$ is huge or the graph
is sparse). In this work, we give single-pass algorithms beating this space
barrier for two classes of problems.
  We present $o(n)$ space algorithms for estimating the number of connected
components with additive error $\varepsilon n$ and
$(1+\varepsilon)$-approximating the weight of minimum spanning tree, for any
small constant $\varepsilon>0$. The latter improves previous $\tilde{O}(n)$
space algorithm given by Ahn et al. (SODA 2012) for connected graphs with
bounded edge weights.
  We initiate the study of approximate graph property testing in the dynamic
streaming model, where we want to distinguish graphs satisfying the property
from graphs that are $\varepsilon$-far from having the property. We consider
the problem of testing $k$-edge connectivity, $k$-vertex connectivity,
cycle-freeness and bipartiteness (of planar graphs), for which, we provide
algorithms using roughly $\tilde{O}(n^{1-\varepsilon})$ space, which is $o(n)$
for any constant $\varepsilon$.
  To complement our algorithms, we present $\Omega(n^{1-O(\varepsilon)})$ space
lower bounds for these problems, which show that such a dependence on
$\varepsilon$ is necessary.


title: Response Selection with Topic Clues for Retrieval-based Chatbots

abstract:
  We consider incorporating topic information into message-response matching to
boost responses with rich content in retrieval-based chatbots. To this end, we
propose a topic-aware convolutional neural tensor network (TACNTN). In TACNTN,
matching between a message and a response is not only conducted between a
message vector and a response vector generated by convolutional neural
networks, but also leverages extra topic information encoded in two topic
vectors. The two topic vectors are linear combinations of topic words of the
message and the response respectively, where the topic words are obtained from
a pre-trained LDA model and their weights are determined by themselves as well
as the message vector and the response vector. The message vector, the response
vector, and the two topic vectors are fed to neural tensors to calculate a
matching score. Empirical study on a public data set and a human annotated data
set shows that TACNTN can significantly outperform state-of-the-art methods for
message-response matching.


title:
Exploiting Social Tie Structure for Cooperative Wireless Networking: A
  Social Group Utility Maximization Framework

abstract:
  In this paper, we develop a social group utility maximization (SGUM)
framework for cooperative wireless networking that takes into account both
social relationships and physical coupling among users. We show that this
framework provides rich modeling flexibility and spans the continuum between
non-cooperative game and network utility maximization (NUM) -- two
traditionally disjoint paradigms for network optimization. Based on this
framework, we study three important applications of SGUM, in database assisted
spectrum access, power control, and random access control, respectively. For
the case of database assisted spectrum access, we show that the SGUM game is a
potential game and always admits a socially-aware Nash equilibrium (SNE). We
develop a randomized distributed spectrum access algorithm that can
asymptotically converge to the optimal SNE, derive upper bounds on the
convergence time, and also quantify the trade-off between the performance and
convergence time of the algorithm. We further show that the performance gap of
SNE by the algorithm from the NUM solution decreases as the strength of social
ties among users increases and the performance gap is zero when the strengths
of social ties among users reach the maximum values. For the cases of power
control and random access control, we show that there exists a unique SNE.
Furthermore, as the strength of social ties increases from the minimum to the
maximum, a player's SNE strategy migrates from the Nash equilibrium strategy in
a standard non-cooperative game to the socially-optimal strategy in network
utility maximization. Furthermore, we show that the SGUM framework can be
generalized to take into account both positive and negative social ties among
users and can be a useful tool for studying network security problems.


title: Discriminators and k-Regular Sequences

abstract:
  The discriminator of an integer sequence s = (s(i))_{i >=0}, introduced by
Arnold, Benkoski, and McCabe in 1985, is the map D_s(n) that sends n >= 1 to
the least positive integer m such that the n numbers s(0), s(1), ..., s(n-1)
are pairwise incongruent modulo m. In this note we consider the discriminators
of a certain class of sequences, the k-regular sequences. We compute the
discriminators of two such sequences, the so-called "evil" and "odious"
numbers, and show they are 2-regular. We also give an example of a k-regular
sequence whose discriminator is not k-regular.
  Finally, we examine sequences that are their own discriminators, and count
the number of length-$n$ finite sequences with this property.


title: Seiberg-Witten monopoles: Weyl metal coupled to chiral magnets

abstract:
  We study a Weyl (semi)metal which couples to local magnets. In the continuum
limit, the Hamiltonian of the system matches the Chern-Simons-Maxwell-Dirac
functional and then the ground state is governed by generalized Seiberg-Witten
(SW) or Freund equations in terms of the sign of Dzyaloshinskii-Moriya
coupling. The ground states determined by the Freund equations may either be
monopolar Weyl semimetal accompanied by the ferromagnetic magnets (MWFM) or SW
monopoles which consist of spheric Weyl fermions coupled to chiral magnets,
depending on the strength of the Kondo coupling. In the latter phase, the
topological ground state is characterized by SW invariants and with a Weyl
surface on which the Weyl metal is of an exotic dispersion $\propto \sqrt k$.
There are also the metastable SW monopole solutions carrying an opposite SW
invariant for the SW equations while the ground state in this case is the MWFM
state.


title:
Polydisperse hard spheres: Crystallization kinetics in small systems and
  role of local structure

abstract:
  We study numerically the crystallization of a hard-sphere mixture with 8\%
polydispersity. Although often used as a model glass former, for small system
sizes we observe crystallization in molecular dynamics simulations. This opens
the possibility to study the competition between crystallization and structural
relaxation of the melt, which typically is out of reach due to the disparate
timescales. We quantify the dependence of relaxation and crystallization times
on density and system size. For one density and system size we perform a
detailed committor analysis to investigate the suitability of local structures
as order parameters to describe the crystallization process. We find that local
structures are strongly correlated with generic bond order and add little
information to the reaction coordinate.


title: Charged Current Coherent Pion Production in Neutrino Scattering

abstract:
  We summarise here the main differences of three models of neutrino-induced
coherent pion production, namely the Rein-Sehgal and Berger-Sehgal models based
on the Partially Conserved Axial Current theorem and the Alvarez-Ruso
\textit{et al.} model which is using a microscopic approach. Their predictions
in the event generators are compared against recent experimental measurements
for a neutrino energy from 0.5 to 20 GeV.


title: Poincar\'e duality complexes with highly connected universal cover

abstract:
  Turaev conjectured that the classification, realization and splitting results
for Poincar\'e duality complexes of dimension $3$ (PD$_{3}$-complexes)
generalize to PD$_{n}$-complexes with $(n-2)$-connected universal cover for $n
\ge 3$. Baues and Bleile showed that such complexes are classified, up to
oriented homotopy equivalence, by the triple consisting of their fundamental
group, orientation class and the image of their fundamental class in the
homology of the fundamental group, verifying Turaev's conjecture on
classification.
  We prove Turaev's conjectures on realization and splitting. We show that a
triple $(G, \omega, \mu)$, comprising a group, $G$, a cohomology class $\omega
\in H^{1}\left(G, \mathbb{Z}/2\mathbb{Z}\right)$ and a homology class $\mu \in
H_{n}(G, \mathbb{Z}^{\omega})$, can be realized by a PD$_{n}$-complex with
$(n-2)$-connected universal cover if and only if the Turaev map applied to
$\mu$ yields is an equivalence. We show that such a PD$_{n}$-complex is a
connected sum of two such complexes if and only if its fundamental group is a
free product of groups.
  We then consider the indecomposable $PD_n$-complexes of this type. When $n$
is odd the results are similar to those for the case $n=3$. The indecomposables
are either aspherical or have virtually free fundamental group. When $n$ is
even the indecomposables include manifolds which are neither aspherical nor
have virtually free fundamental group, but if the group is virtually free and
has no dihedral subgroup of order $>2$ then it has two ends.


title:
Application of artificial neural networks and genetic algorithms for
  crude fractional distillation process modeling

abstract:
  This work presents the application of the artificial neural networks, trained
and structurally optimized by genetic algorithms, for modeling of crude
distillation process at PKN ORLEN S.A. refinery. Models for the main
fractionator distillation column products were developed using historical data.
Quality of the fractions were predicted based on several chosen process
variables. The performance of the model was validated using test data. Neural
networks used in companion with genetic algorithms proved that they can
accurately predict fractions quality shifts, reproducing the results of the
standard laboratory analysis. Simple knowledge extraction method from neural
network model built was also performed. Genetic algorithms can be successfully
utilized in efficient training of large neural networks and finding their
optimal structures.


title:
Interacting electrodynamics of short coherent conductors in quantum
  circuits

abstract:
  When combining lumped mesoscopic electronic components to form a circuit,
quantum fluctuations of electrical quantities lead to a non-linear
electromagnetic interaction between the components that is not generally
understood. The Landauer-B\"uttiker formalism that is frequently used to
describe non-interacting coherent mesoscopic components is not directly suited
to describe such circuits since it assumes perfect voltage bias, i.e. the
absence of fluctuations. Here, we show that for short coherent conductors of
arbitrary transmission, the Landauer-B\"uttiker formalism can be extended to
take into account quantum voltage fluctuations similarly to what is done for
tunnel junctions. The electrodynamics of the whole circuit is then formally
worked out disregarding the non-Gaussianity of fluctuations. This reveals how
the aforementioned non-linear interaction operates in short coherent
conductors: voltage fluctuations induce a reduction of conductance through the
phenomenon of dynamical Coulomb blockade but they also modify their internal
density of states leading to an additional electrostatic modification of the
transmission. Using this approach we can account quantitatively for conductance
measurements performed on Quantum Point Contacts in series with impedances of
the order of $R_K = h / e^2$. Our work should enable a better engineering of
quantum circuits with targeted properties.


title:
Micromagnetic Simulation of Amorphous Ferrimagnetic TbFeCo Films with
  Exchange Coupled Nanophases

abstract:
  Amorphous ferrimagnetic TbFeCo thin films are found to exhibit exchange bias
effect near the compensation temperature by magnetic hysteresis loop
measurement. The observed exchange anisotropy is believed to originate from the
exchange interaction between the two nanoscale amorphous phases distributed
within the films. Here, we present a computational model of phase-separated
TbFeCo using micromagnetic simulation. Two types of cells with different Tb
concentration are distributed within the simulated space to obtain a
heterogeneous structure consisting of two nanoscale amorphous phases. Each cell
contains separated Tb and FeCo components, forming two antiferromagnetically
coupled sublattices. Using this model, we are able to show the existence of
exchange bias effect, and the shift in hysteresis loops is in agreement with
experiment. The micromagnetic model developed herein for a heterogeneous
magnetic material may also account for some recent measurements of exchange
bias effect in crystalline films.


title:
Study the effect of beam energy spread and detector resolution on the
  search for Higgs boson decays to invisible particles at a future e$^+$e$^-$
  circular collider

abstract:
  We study the expected sensitivity to measure the branching ratio of Higgs
boson decays to invisible particles at a future circular \epem collider
(FCC-ee) in the process $e^+e^-\to HZ$ with $Z\to \ell^+\ell^-$ ($\ell=e$ or
$\mu$) using an integrated luminosity of 3.5 ab$^{-1}$ at a center-of-mass
energy $\sqrt{s}=240$ GeV. The impact of the energy spread of the FCC-ee beam
and of the resolution in the reconstruction of the leptons is discussed. %Two
different detector concepts are considered: a detector corresponding to the CMS
reconstruction performances and the expected design of the ILC detector. The
minimum branching ratio for a $5\sigma$ observation after 3.5ab$^{-1}$ of data
taking is $1.7\pm 0.1\%(stat+syst) $. The branching ratio exclusion limit at
95\% CL is $0.63 \pm 0.22\%((stat+syst))$.


title:
Comparative Analysis of Initial Access Techniques in 5G mmWave Cellular
  Networks

abstract:
  The millimeter wave frequencies (roughly above 10 GHz) offer the availability
of massive bandwidth to greatly increase the capacity of fifth generation (5G)
cellular wireless systems. However, to overcome the high isotropic pathloss at
these frequencies, highly directional transmissions will be required at both
the base station (BS) and the mobile user equipment (UE) to establish
sufficient link budget in wide area networks. This reliance on directionality
has important implications for control layer procedures. Initial access in
particular can be significantly delayed due to the need for the BS and the UE
to find the initial directions of transmission. This paper provides a survey of
several recently proposed techniques. Detection probability and delay analysis
is performed to compare various techniques including exhaustive and iterative
search. We show that the optimal strategy depends on the target SNR regime.


title:
Ill-posedness of the Prandtl equations in Sobolev spaces around a shear
  flow with general decay

abstract:
  Motivated by the paper by D. Gerard-Varet and E. Dormy [JAMS, 2010] about the
linear ill-posedness for the Prandtl equations around a shear flow with
exponential decay in normal variable, and the recent study of well-posedness on
the Prandtl equations in Sobolev spaces, this paper aims to extend the result
in \cite{GV-D} to the case when the shear flow has general decay. The key
observation is to construct an approximate solution that captures the initial
layer to the linearized problem motivated by the precise formulation of
solutions to the inviscid Prandtl equations.


title: On Topologically Massive Gravity with Extended Supersymmetry

abstract:
  We describe the construction of $2+1$-dimensional toplogically massive adS
gravity with ${\mathcal{N}}$-extended supersymmetry in superspace by means of
introducing a compensating hypermultiplet for the super-Weyl invariance. For
$\mathcal{N}\geq 3$ the scalar multiplet must be on shell and the potential for
the scalar compensator is completely determined by the geometry. As a
consequence the resulting massive theory has no free parameter for
$\mathcal{N}\geq 4$. For $\mathcal{N}= 4$ we show that this leads to
topologically massive gravity at the chiral point and construct the
corresponding off-shell component action.


title:
Inhibitory geostatistical designs for spatial prediction taking account
  of uncertain covariance structure

abstract:
  The problem of choosing spatial sampling designs for investigating unobserved
spatial phenomenon S arises in many contexts, for example in identifying
households to select for a prevalence survey to study disease burden and
heterogeneity in a study region D. We studied randomised inhibitory spatial
sampling designs to address the problem of spatial prediction whilst taking
account of the need to estimate covariance structure. Two specific classes of
design are inhibitory designs and inhibitory designs plus close pairs. In an
inhibitory design, any pair of sample locations must be separated by at least
an inhibition distance {$\delta$}. In an inhibitory plus close pairs design, n
- k sample locations in an inhibitory design with inhibition distance
{$\delta$} are augmented by k locations each positioned close to one of the
randomly selected n - k locations in the inhibitory design, uniformly
distributed within a disc of radius {$\zeta$}. We present simulation results
for the Matern class of covariance structures. When the nugget variance is
non-negligible, inhibitory plus close pairs designs demonstrate improved
predictive efficiency over designs without close pairs. We illustrate how these
findings can be applied to the design of a rolling Malaria Indicator Survey
that forms part of an ongoing large-scale, five-year malaria transmission
reduction project in Malawi.


title: Multi-Connectivity in 5G mmWave Cellular Networks

abstract:
  The millimeter wave (mmWave) frequencies offer the potential of orders of
magnitude increases in capacity for next-generation cellular wireless systems.
However, links in mmWave networks are highly susceptible to blocking and may
suffer from rapid variations in quality. Connectivity to multiple cells - both
in the mmWave and in the traditional lower frequencies - is thus considered
essential for robust connectivity. However, one of the challenges in supporting
multi-connectivity in the mmWave space is the requirement for the network to
track the direction of each link in addition to its power and timing. With
highly directional beams and fast varying channels, this directional tracking
may be the main bottleneck in realizing robust mmWave networks. To address this
challenge, this paper proposes a novel measurement system based on (i) the UE
transmitting sounding signals in directions that sweep the angular space, (ii)
the mmWave cells measuring the instantaneous received signal strength along
with its variance to better capture the dynamics and, consequently, the
reliability of a channel/direction and, finally, (iii) a centralized controller
making handover and scheduling decisions based on the mmWave cell reports and
transmitting the decisions either via a mmWave cell or conventional microwave
cell (when control signaling paths are not available). We argue that the
proposed scheme enables efficient and highly adaptive cell selection in the
presence of the channel variability expected at mmWave frequencies.


title: Langevin equation with fluctuating diffusivity: a two-state model

abstract:
  Recently, anomalous subdiffusion, aging, and scatter of the diffusion
coefficient have been reported in many single-particle-tracking experiments,
though origins of these behaviors are still elusive. Here, as a model to
describe such phenomena, we investigate a Langevin equation with diffusivity
fluctuating between a fast and a slow state. We assume that the sojourn time
distributions of these two states are given by power laws. It is shown that,
for a non-equilibrium ensemble, the ensemble-averaged mean square displacement
(MSD) shows transient subdiffusion. In contrast, the time-averaged MSD shows
normal diffusion, but an effective diffusion coefficient transiently shows
aging behavior. The propagator is non-Gaussian for short time, and converges to
a Gaussian distribution in a long time limit; this convergence to Gaussian is
extremely slow for some parameter values. For equilibrium ensembles, both
ensemble-averaged and time-averaged MSDs show only normal diffusion, and thus
we cannot detect any traces of the fluctuating diffusivity with these MSDs.
Therefore, as an alternative approach to characterize the fluctuating
diffusivity, the relative standard deviation (RSD) of the time-averaged MSD is
utilized, and it is shown that the RSD exhibits slow relaxation as a signature
of the long-time correlation in the fluctuating diffusivity. Furthermore, it is
shown that the RSD is related to a non-Gaussian parameter of the propagator. To
obtain these theoretical results, we develop a two-state renewal theory as an
analytical tool.


title: Fast Polarization Switch for Polarization-Based Quantum Communication

abstract:
  We present a complete optoelectronic unit for polarization visualization,
switching and control. The system is based on an FPGA unit and comprises: an
acquisition unit containing an analog polarimeter and digital-to-analog
converters, an FPGA capable of implementing an optimal algorithm for
three-stage arbitrary polarization tracking, and an electronic driver with
analog-to-digital converters capable of interfacing with Lithium-Niobate-based
Polarization Controllers. The results, determined via simulation of
real-parameter devices, show that fast polarization switch is achievable.


title:
An analysis of visitors' length of stay through noninvasive Bluetooth
  monitoring in the Louvre Museum

abstract:
  Art Museums traditionally employ observations and surveys to enhance their
knowledge of visitors' behavior and experience. However, these approaches often
produce spatially and temporally limited empirical evidence and measurements.
Only recently has the ubiquity of digital technologies revolutionized the
ability to collect data on human behavior. Consequently, the greater
availability of large-scale datasets based on quantifying visitors' behavior
provides new opportunities to apply computational and comparative analytical
techniques. In this paper, we attempt to analyze visitors' behavior in the
Louvre Museum from anonymized longitudinal datasets collected from noninvasive
Bluetooth sensors. We examine visitors' length of stay in the museum and
consider this relationship with occupation density around artwork. This data
analysis increases the knowledge and understanding of museum professionals
related to the experience of visitors.


title:
Thermal stimulated current response in cupric oxide single crystal thin
  films over a wide temperature range

abstract:
  Cupric oxide single crystal thin films were grown by plasma-assisted
molecular beam epitaxy. X-ray diffraction, Raman spectrum and in situ
reflection high-energy electron diffraction show that the thin films are 2x2
reconstructed with an in-plane compression and out-of-plane stretching. Thermal
stimulated current measurement indicates that the electric polarization
response presents in the special 2D cupric oxide single crystal thin film over
a wide temperature range from 130 K to near-room temperature. We infer that the
abnormal electric response involves the changing of phase transition
temperature induced by structure distortion, the spin frustration and magnetic
fluctuation effect of short-range magnetic order, or the combined action of
both two factors mentioned above. This work suggests a promising clue for
finding new room temperature single phase multiferroics or tuning phase
transition temperature.


title:
MIMO Precoding for Networked Control Systems with Energy Harvesting
  Sensors

abstract:
  In this paper, we consider a MIMO networked control system with an energy
harvesting sensor, where an unstable MIMO dynamic system is connected to a
controller via a MIMO fading channel. We focus on the energy harvesting and
MIMO precoding design at the sensor so as to stabilize the unstable MIMO
dynamic plant subject to the energy availability constraint at the sensor.
Using the Lyapunov optimization approach, we propose a closed-form dynamic
energy harvesting and dynamic MIMO precoding solution, which has an
event-driven control structure. Furthermore, the MIMO precoding solution is
shown to have an eigenvalue water-filling structure, where the water level
depends on the state estimation covariance, energy queue and the channel state,
and the sea bed level depends on the state estimation covariance. The proposed
scheme is also compared with various baselines and we show that significant
performance gains can be achieved.


title:
Minimally complex ion traps as modules for quantum communication and
  computing

abstract:
  Optically linked ion traps are promising as components of network-based
quantum technologies, including communication systems and modular computers.
Experimental results achieved to date indicate that the fidelity of operations
within each ion trap module will be far higher than the fidelity of operations
involving the links; fortunately internal storage and processing can
effectively upgrade the links through the process of purification. Here we
perform the most detailed analysis to date on this purification task, using a
protocol which is balanced to maximise fidelity while minimising the device
complexity and the time cost of the process. Moreover we 'compile down' the
quantum circuit to device-level operations including cooling and shutting
events. We find that a linear trap with only five ions (two of one species,
three of another) can support our protocol while incorporating desirable
features such as 'global control', i.e. laser control pulses need only target
an entire zone rather than differentiating one ion from its neighbour. To
evaluate the capabilities of such a module we consider its use both as a
universal communications node for quantum key distribution, and as the basic
repeating unit of a quantum computer. For the latter case we evaluate the
threshold for fault tolerant quantum computing using the surface code, finding
acceptable fidelities for the 'raw' entangling link as low as 83% (or under 75%
if an additional ion is available).


title:
Uniqueness Theorems for Subharmonic and Holomorphic Functions of Several
  Variables on a Domain

abstract:
  We establish a general uniqueness theorem for subharmonic functions of
several variables on a domain. A corollary from this uniqueness theorem for
holomorphic functions is formulated in terms of the zero subset of holomorphic
functions and restrictions on the growth of functions near the boundary of
domain.


title:
Improving practical sensitivity of energy optimized wake-up receivers:
  proof of concept in 65nm CMOS

abstract:
  We present a high performance low-power digital base-band architecture,
specially designed for an energy optimized duty-cycled wake-up receiver scheme.
Based on a careful wake-up beacon design, a structured wake-up beacon detection
technique leads to an architecture that compensates for the implementation loss
of a low-power wake-up receiver front-end at low energy and area costs. Design
parameters are selected by energy optimization and the architecture is easily
scalable to support various network sizes. Fabricated in 65nm CMOS, the digital
base-band consumes 0.9uW (V_DD=0.37V) in sub-threshold operation at 250kbps,
with appropriate 97% wake-up beacon detection and 0.04% false alarm
probabilities. The circuit is fully functional at a minimum V_DD of 0.23V at
f_max=5kHz and 0.018uW power consumption. Based on these results we show that
our digital base-band can be used as a companion to compensate for front-end
implementation losses resulting from the limited wake-up receiver power budget
at a negligible cost. This implies an improvement of the practical sensitivity
of the wake-up receiver, compared to what is traditionally reported.


title: Plastic deformation of tubular crystals by dislocation glide

abstract:
  Tubular crystals, two-dimensional lattices wrapped into cylindrical
topologies, arise in many contexts, including botany and biofilaments, and in
physical systems such as carbon nanotubes. The geometrical principles of
botanical phyllotaxis, describing the spiral packings on cylinders commonly
found in nature, have found application in all these systems. Several recent
studies have examined defects in tubular crystals associated with crystalline
packings that must accommodate a fixed tube radius. Here, we study the
mechanics of tubular crystals with variable tube radius, with dislocations
interposed between regions of different phyllotactic packings. Unbinding and
separation of dislocation pairs with equal and opposite Burgers vectors allow
the growth of one phyllotactic domain at the expense of another. In particular,
glide separation of dislocations offers a low-energy mode for plastic
deformations of solid tubes in response to external stresses, reconfiguring the
lattice step by step. Through theory and simulation, we examine how the tube's
radius and helicity affects, and is in turn altered by, the mechanics of
dislocation glide. We also discuss how a sufficiently strong bending rigidity
can alter or arrest the deformations of tubes with small radii.


title:
Adjoint eigenfunctions of temporally recurrent single-spiral solutions
  in a simple model of atrial fibrillation

abstract:
  This paper introduces a numerical method for computing the spectrum of
adjoint (left) eigenfunctions of spiral wave solutions to reaction-diffusion
systems in arbitrary geometries. The method is illustrated by computing over a
hundred eigenfunctions associated with an unstable time-periodic single-spiral
solution of the Karma model on a square domain. We show that all leading
adjoint eigenfunctions are exponentially localized in the vicinity of the
spiral tip, although the marginal modes (response functions) demonstrate the
strongest localization. We also discuss the implications of the localization
for the dynamics and control of unstable spiral waves. In particular, the
interaction with no-flux boundaries leads to a drift of spiral waves which can
be understood with the help of the response functions.


title:
Measurement of the integrated and differential t-tbar production cross
  sections for high-pt top quarks in pp collisions at sqrt(s) = 8 TeV

abstract:
  The cross section for pair production of top quarks (t-tbar) with high
transverse momenta is measured in pp collisions, collected with the CMS
detector at the LHC with sqrt(s) = 8 TeV in data corresponding to an integrated
luminosity of 19.7 inverse femtobarns. The measurement is performed using
lepton+jets events, where one top quark decays semileptonically, while the
second top quark decays to a hadronic final state. The hadronic decay is
reconstructed as a single, large-radius jet, and identified as a top quark
candidate using jet substructure techniques. The integrated cross section and
the differential cross sections as a function of top quark pt and rapidity are
measured at particle level within a fiducial region related to the
detector-level requirements and at parton level. The particle-level integrated
cross section is found to be sigma[t-tbar] = 0.499 +/- 0.035 (stat+syst) +/-
0.095 (theory) +/- 0.013 (lumi) pb for top quark pt > 400 GeV. The parton-level
measurement is sigma[t-tbar] = 1.44 +/- 0.10 (stat+syst) +/- 0.29 (theory) +/-
0.04 (lumi) pb. The integrated and differential cross section results are
compared to predictions from several event generators.


title:
Existence of equilibrium for generalized games in choice form and
  applications

abstract:
  This paper has two central aims: first, to provide simple conditions under
which the generalized games in choice form and, consequently, the abstract
economies, admit equilibrium; second, to study the solvability of several types
of systems of vector quasi-equilibrium problems as an application. Our work
outlines that there still is much to be gained from using the results
concerning the existence of equilibrium of games as tools of research for other
optimization problems.


title: Eigenvectors of the critical 1-dimensional random Schroedinger operator

abstract:
  The purpose of this paper is to understand in more detail the shape of the
eigenvectors of the random Schroedinger operator H = Delta+V. Here Delta is the
discrete Laplacian and V is a random potential. It is well known that under
certain assumptions on V the spectrum of this operator is pure point and its
eigenvectors are exponentially localized; a phenomenon known as Anderson
Localization. We restrict the operator to Z_n and consider the critical model
H_n. We show that the shape of a uniformly chosen eigenvector of H_n converges
in law to exp (-|t|/4 + Z_t/sqrt(2)), where Z is two-sided Brownian motion.


title: Automatic Parameter Derivations in k2U Framework

abstract:
  We have recently developed a general schedulability test framework, called
k2U, which can be applied to deal with a large variety of task models that have
been widely studied in real-time embedded systems. The k2U framework provides
several means for the users to convert arbitrary schedulability tests
(regardless of platforms and task models) into polynomial-time tests with
closed mathematical expressions. However, the applicability (as well as the
performance) of the k2U framework relies on the users to index the tasks
properly and define certain constant parameters.
  This report describes how to automatically index the tasks properly and
derive those parameters. We will cover several typical schedulability tests in
real-time systems to explain how to systematically and automatically derive
those parameters required by the k2U framework. This automation significantly
empowers the k2U framework to handle a wide range of classes of real-time
execution platforms and task models, including uniprocessor scheduling,
multiprocessor scheduling, self-suspending task systems, real-time tasks with
arrival jitter, services and virtualizations with bounded delays, etc.


title:
Tuning of magnetic quantum criticality in artificial Kondo superlattice
  CeRhIn5/YbRhIn5

abstract:
  The effects of reduced dimensions and the interfaces on antiferromagnetic
quantum criticality are studied in epitaxial Kondo superlattices, with
alternating $n$ layers of heavy-fermion antiferromagnet CeRhIn$_5$ and 7 layers
of normal metal YbRhIn$_5$. As $n$ is reduced, the Kondo coherence temperature
is suppressed due to the reduction of effective Kondo screening. The N\'{e}el
temperature is gradually suppressed as $n$ decreases and the quasiparticle mass
is strongly enhanced, implying dimensional control toward quantum criticality.
Magnetotransport measurements reveal that a quantum critical point is reached
for $n=3$ superlattice by applying small magnetic fields. Remarkably, the
anisotropy of the quantum critical field is opposite to the expectations from
the magnetic susceptibility in bulk CeRhIn$_5$, suggesting that the Rashba
spin-orbit interaction arising from the inversion symmetry breaking at the
interface plays a key role for tuning the quantum criticality in the
two-dimensional Kondo lattice.


title:
The role of average time dependence on the relaxation of excited
  electron populations in nonequilibrium many-body physics

abstract:
  We examine the exact equation of motion for the relaxation of populations of
strongly correlated electrons after a nonequilibrium excitation by a pulsed
field, and prove that the populations do not change when the Green's functions
have no average time dependence. We show how the average time dependence enters
into the equation of motion to lowest order and describe what governs the
relaxation process of the electron populations in the long-time limit. While
this result may appear, on the surface, to be required by any steady-state
solution, the proof is nontrivial, and provides new critical insight into how
nonequilibrium populations relax, which goes beyond the assumption that they
thermalize via a simple relaxation rate determined by the imaginary part of the
self-energy, or that they can be described by a quasi-equilibrium condition
with a Fermi-Dirac distribution and a time-dependent temperature. We also
discuss the implications of this result to approximate theories, which may not
satisfy the exact relation in the equation of motion.


title:
An Improved System for Sentence-level Novelty Detection in Textual
  Streams

abstract:
  Novelty detection in news events has long been a difficult problem. A number
of models performed well on specific data streams but certain issues are far
from being solved, particularly in large data streams from the WWW where
unpredictability of new terms requires adaptation in the vector space model. We
present a novel event detection system based on the Incremental Term
Frequency-Inverse Document Frequency (TF-IDF) weighting incorporated with
Locality Sensitive Hashing (LSH). Our system could efficiently and effectively
adapt to the changes within the data streams of any new terms with continual
updates to the vector space model. Regarding miss probability, our proposed
novelty detection framework outperforms a recognised baseline system by
approximately 16% when evaluating a benchmark dataset from Google News.


title:
Scalar waves in regular Bardeen black holes: Scattering, absorption and
  quasinormal modes

abstract:
  We discuss the phenomenology of massless scalar fields around a regular
Bardeen black hole, namely absorption cross section, scattering cross section
and quasinormal modes. We compare the Bardeen and Reissner-Nordstr\"om black
holes, showing limiting cases for which their properties are similar.


title:
A Note on the Exact Schedulability Analysis for Segmented
  Self-Suspending Systems

abstract:
  This report considers a sporadic real-time task system with $n$ sporadic
tasks on a uniprocessor platform, in which the lowest-priority task is a
segmented self-suspension task and the other higher-priority tasks are ordinary
sporadic real-time tasks. This report proves that the schedulability analysis
for fixed-priority preemptive scheduling even with only one segmented
self-suspending task as the lowest-priority task is $co{\cal NP}$-hard in the
strong sense. Under fixed-priority preemptive scheduling, Nelissen et al. in
ECRTS 2015 provided a mixed-integer linear programming (MILP) formulation to
calculate an upper bound on the worst-case response time of the lowest-priority
self-suspending task. This report provides a comprehensive support to explain
several hidden properties that were not provided in their paper. We also
provide an input task set to explain why the resulting solution of their MILP
formulation can be quite far from the exact worst-case response time.


title:
Efficiency of minimizing compositions of convex functions and smooth
  maps

abstract:
  We consider global efficiency of algorithms for minimizing a sum of a convex
function and a composition of a Lipschitz convex function with a smooth map.
The basic algorithm we rely on is the prox-linear method, which in each
iteration solves a regularized subproblem formed by linearizing the smooth map.
When the subproblems are solved exactly, the method has efficiency
$\mathcal{O}(\varepsilon^{-2})$, akin to gradient descent for smooth
minimization. We show that when the subproblems can only be solved by
first-order methods, a simple combination of smoothing, the prox-linear method,
and a fast-gradient scheme yields an algorithm with complexity
$\widetilde{\mathcal{O}}(\varepsilon^{-3})$. The technique readily extends to
minimizing an average of $m$ composite functions, with complexity
$\widetilde{\mathcal{O}}(m/\varepsilon^{2}+\sqrt{m}/\varepsilon^{3})$ in
expectation. We round off the paper with an inertial prox-linear method that
automatically accelerates in presence of convexity.


title:
Analytical method to determine flexoelectric coupling coefficient at
  nanoscale

abstract:
  Flexoelectricity is defined as the coupling between strain gradient and
polarization, which is expected to be remarkable at nanoscale. However,
measuring the flexoelectricity at nanoscale is challenging. In the present
work, an analytical method for measuring the flexoelectric coupling coefficient
based on nanocompression technique is proposed. It is found that the
flexoelectricity can induce stiffness softening of dielectric
nano-cone-frustum. This phenomenon becomes more significant when the sample
size decreases or the half cone angle increases. This method avoids measuring
the electric polarization or current at nanoscale with dynamical loading, which
can be beneficial to the flexoelectric measurement at nanoscale and design of
flexoelectric nanodevices.


title: Holographic Software for Quantum Networks

abstract:
  We introduce a pictorial approach to quantum information, called holographic
software. Our software captures both algebraic and topological aspects of
quantum networks. It yields a bi-directional dictionary to translate between a
topological approach and an algebraic approach. Using our software, we give a
topological simulation for quantum networks. The string Fourier transform (SFT)
is our basic tool to transform product states into states with maximal
entanglement entropy. We obtain a pictorial interpretation of Fourier
transformation, of measurements, and of local transformations, including the
$n$-qudit Pauli matrices and their representation by Jordan-Wigner
transformations.
  We use our software to discover interesting new protocols for multipartite
communication. In summary, we build a bridge linking the theory of planar para
algebras with quantum information.

categories: quant-ph hep-th math-ph math.MP math.OA math.QA


title: f-Biharmonic maps and f-biharmonic submanifolds II

abstract:
  We continue our study [Ou4] of f-biharmonic maps and f-biharmonic
submanifolds by exploring the applications of f-biharmonic maps and the
relationships among biharmonicity, f-biharmonicity and conformality of maps
between Riemannian manifolds. We are able to characterize harmonic maps and
minimal submanifolds by using the concept of f-biharmonic maps and prove that
the set of all f-biharmonic maps from 2-dimensional domain is invariant under
the conformal change of the metric on the domain. We give an improved equation
for f-biharmonic hypersurfaces and use it to prove some rigidity theorems about
f-biharmonic hypersurfaces in nonpositively curved manifolds, and to give some
classifications of f-biharmonic hypersurfaces in Einstein spaces and in space
forms. Finally, we also use the improved f-biharmonic hypersurface equation to
obtain an improved equation and some classifications of biharmonic conformal
immersions of surfaces into a 3-manifold.


title:
3D Keypoint Detection Based on Deep Neural Network with Sparse
  Autoencoder

abstract:
  Researchers have proposed various methods to extract 3D keypoints from the
surface of 3D mesh models over the last decades, but most of them are based on
geometric methods, which lack enough flexibility to meet the requirements for
various applications. In this paper, we propose a new method on the basis of
deep learning by formulating the 3D keypoint detection as a regression problem
using deep neural network (DNN) with sparse autoencoder (SAE) as our regression
model. Both local information and global information of a 3D mesh model in
multi-scale space are fully utilized to detect whether a vertex is a keypoint
or not. SAE can effectively extract the internal structure of these two kinds
of information and formulate high-level features for them, which is beneficial
to the regression model. Three SAEs are used to formulate the hidden layers of
the DNN and then a logistic regression layer is trained to process the
high-level features produced in the third SAE. Numerical experiments show that
the proposed DNN based 3D keypoint detection algorithm outperforms current five
state-of-the-art methods for various 3D mesh models.


title:
On a decomposition of regular domains into John domains with uniform
  constants

abstract:
  We derive a decomposition result for regular, two-dimensional domains into
John domains with uniform constants. We prove that for every simply connected
domain $\Omega \subset {\Bbb R}^2$ with $C^1$-boundary there is a corresponding
partition $\Omega = \Omega_1 \cup \ldots \cup \Omega_N$ with $\sum_{j=1}^N
\mathcal{H}^1(\partial \Omega_j \setminus \partial \Omega) \le \theta$ such
that each component is a John domain with a John constant only depending on
$\theta$. The result implies that many inequalities in Sobolev spaces such as
Poincar\'e's or Korn's inequality hold on the partition of $\Omega$ for uniform
constants, which are independent of $\Omega$.


title: Some experiments on the growth of Mertens matrices

abstract:
  We give some experimental observations on the growth of the norm of certain
matrices related to the Mertens function. The results obtained in these
experiments convince us that linear algebra may help in the study of Mertens
function and other arithmetic functions.


title: A systematic construction of finite element commuting exact sequences

abstract:
  We present a systematic construction of finite element exact sequences with a
commuting diagram for the de Rham complex in one-, two- and three-space
dimensions. We apply the construction in two-space dimensions to rediscover two
families of exact sequences for triangles and three for squares, and to uncover
one new family of exact sequence for squares and two new families of exact
sequences for general polygonal elements. We apply the construction in
three-space dimensions to rediscover two families of exact sequences for
tetrahedra, three for cubes, and one for prisms; and to uncover four new
families of exact sequences for pyramids, three for prisms, and one for cubes.


title:
Accelerated High-Resolution Photoacoustic Tomography via Compressed
  Sensing

abstract:
  Current 3D photoacoustic tomography (PAT) systems offer either high image
quality or high frame rates but are not able to deliver high spatial and
temporal resolution simultaneously, which limits their ability to image dynamic
processes in living tissue. A particular example is the planar Fabry-Perot (FP)
scanner, which yields high-resolution images but takes several minutes to
sequentially map the photoacoustic field on the sensor plane, point-by-point.
However, as the spatio-temporal complexity of many absorbing tissue structures
is rather low, the data recorded in such a conventional, regularly sampled
fashion is often highly redundant. We demonstrate that combining variational
image reconstruction methods using spatial sparsity constraints with the
development of novel PAT acquisition systems capable of sub-sampling the
acoustic wave field can dramatically increase the acquisition speed while
maintaining a good spatial resolution: First, we describe and model two general
spatial sub-sampling schemes. Then, we discuss how to implement them using the
FP scanner and demonstrate the potential of these novel compressed sensing PAT
devices through simulated data from a realistic numerical phantom and through
measured data from a dynamic experimental phantom as well as from in-vivo
experiments. Our results show that images with good spatial resolution and
contrast can be obtained from highly sub-sampled PAT data if variational image
reconstruction methods that describe the tissues structures with suitable
sparsity-constraints are used. In particular, we examine the use of total
variation regularization enhanced by Bregman iterations. These novel
reconstruction strategies offer new opportunities to dramatically increase the
acquisition speed of PAT scanners that employ point-by-point sequential
scanning as well as reducing the channel count of parallelized schemes that use
detector arrays.


title: SNO+ scintillator cocktail studies using an ${}^{90}$Y source

abstract:
  We present the design of an ${}^{90}$Y calibration source and its
manufacturing procedure, that has been implemented in the University of Sussex
radioactive laboratory. The radioactive source was first tested at the
University of Sussex using a small scintillator cocktail sample. Further
measurements were performed at the University of Pennsylvania using a larger
volume of the scintillator cocktail. The results of both studies are presented
and discussed.


title: Wrinkling of a thin film on a nematic liquid crystal elastomer

abstract:
  Wrinkles commonly develop in a thin film deposited on a soft elastomer
substrate when the film is subject to compression. Motivated by recent
experiments [Agrawal et al., Soft Matter 8, 7138 (2012)] that show how wrinkle
morphology can be controlled by using a nematic elastomer substrate, we develop
the theory of small-amplitude wrinkles of an isotropic film atop a nematic
elastomer. The directors of the nematic elastomer are assumed to lie in a plane
parallel to the plane of the undeformed film. For uniaxial compression of the
film along the direction perpendicular to the elastomer directors, the system
behaves as a compressed film on an isotropic substrate. When the uniaxial
compression is along the direction of nematic order, we find that the soft
elasticity characteristic of liquid crystal elastomers leads to a critical
stress for wrinkling which is very small compared to the case of an isotropic
substrate. We also determine the wavelength of the wrinkles at the critical
stress, and show how the critical stress and wavelength depend on substrate
depth and the anisotropy of the polymer chains in the nematic elastomer.


title: Networks of Complements

abstract:
  We consider a network of sellers, each selling a single product, where the
graph structure represents pair-wise complementarities between products. We
study how the network structure affects revenue and social welfare of
equilibria of the pricing game between the sellers. We prove positive and
negative results, both of "Price of Anarchy" and of "Price of Stability" type,
for special families of graphs (paths, cycles) as well as more general ones
(trees, graphs). We describe best-reply dynamics that converge to non-trivial
equilibrium in several families of graphs, and we use these dynamics to prove
the existence of approximately-efficient equilibria.


title: On Leader Green Election

abstract:
  We investigate the number of survivors in the Leader Green Election (LGE)
algorithm introduced by P. Jacquet, D. Milioris and P. Muhlethaler in 2013. Our
method is based on the Rice method and gives quite precise formulas. We derive
upper bounds on the number of survivors in this algorithm and we propose a
proper use of LGE.
  Finally, we discuss one property of a general urns and balls problem and show
a lower bound for a required number of rounds for a large class of distributed
leader election protocols.


title: Introduction to W-algebras and their representation theory

abstract:
  These are lecture notes from author's mini-course during Session 1: "Vertex
algebras, W-algebras, and application" of INdAM Intensive research period
"Perspectives in Lie Theory", at the Centro di Ricerca Matematica Ennio De
Giorgi, Pisa, Italy. December 9, 2014 -- February 28, 2015.


title: Random cluster dynamics for the Ising model is rapidly mixing

abstract:
  We show that the mixing time of Glauber (single edge update) dynamics for the
random cluster model at $q=2$ is bounded by a polynomial in the size of the
underlying graph. As a consequence, the Swendsen-Wang algorithm for the
ferromagnetic Ising model at any temperature has the same polynomial mixing
time bound.


title:
Comprehensive Analysis of Yukawa Hierarchies on $T^2/Z_N$ with Magnetic
  Fluxes

abstract:
  Based on the result of classification in our previous work, we exhaustively
investigate Yukawa sector of $U(8)$ model on magnetized orbifolds
$T^{2}/Z_{2}$, $T^{2}/Z_{3}$, $T^{2}/Z_{4}$ and $T^{2}/Z_{6}$ by evaluating
ratios of the mass eigenvalues of the three states in all the possible
configurations with one and two Higgs pairs where three generations are
realized in fermions. Because of smearing effect via kinetic mixing, one can
realize a hierarchy such as $10^{-2}$-$10^{-3}$, but it is very difficult to
achieve the mass ratio between the up and top quarks
($m_{\text{up}}/m_{\text{top}} \sim 10^{-5}$) on the complicated magnetized
orbifolds $T^{2}/Z_{N}\,(N=3,4,6)$.


title:
Using the T2K near detector to study electron neutrino charged current
  quasi-elastic-like interactions on carbon

abstract:
  In T2K $\nu_{\mu} \rightarrow \nu_{e}$ oscillation analyses, electron
neutrinos are the signal at the far detector. For the beam peak energy, $\sim
0.6 \,$GeV, charged current quasi-elastic (CCQE) neutrino interactions
dominate. Here we use the T2K near detector to measure electron neutrino
CCQE-like interactions, which are defined by having no pions exit the nucleus:
$\nu_e \,$CC$\,0\pi$. The selection, backgrounds and steps towards a cross
section measurement on carbon are presented.


title: Entropy spectrum of BTZ black hole in massive gravity

abstract:
  We study the entropy spectrum of (2+1) BTZ black holes in massive gravity
models. We use the formalism proposed by Jiang and Han where black hole
property of adiabaticity and the oscillating velocity of the black hole horizon
are used to investigate the quantization of the entropy of such systems. We
find that the entropy of the BTZ black holes in massive gravity is quantized
with equally spaced spectra.


title: Performance of the ALICE secondary vertex b-tagging algorithm

abstract:
  The identification of jets originating from beauty quarks in heavy-ion
collisions is important to study the properties of the hot and dense matter
produced in such collisions. A variety of algorithms for b-jet tagging was
elaborated at the LHC experiments. They rely on the properties of B hadrons,
i.e. their long lifetime, large mass and large multiplicity of decay products.
In this work, the b-tagging algorithm based on displaced secondary-vertex
topologies is described. We present Monte Carlo based performance studies of
the algorithm for charged jets reconstructed with the ALICE tracking system in
p-Pb collisions at $\sqrt{s_\text{NN}}$ = 5.02 TeV. The tagging efficiency,
rejection rate and the correction of the smearing effects of non-ideal detector
response are presented.


title:
Effects of Substituents in Polyvinylcarbazole Structures on Their
  Optical Properties

abstract:
  Absorption, photoluminescence, and photoluminescence excitation spectra of
solutions and thin films of N-vinylcarbazole polymers and copolymers with
various substituents directly on the carbazole moiety and on the polymer chain
were studied comprehensively. Polymers that were used previously to develop
polymer composites with polymethine dyes having photosensitivity over a broad
spectral range including the visible and near-IR regions were selected for the
studies.


title:
Algebraic theory of endohedrally confined diatomic molecules:
  application to H$_2$@C$_{60}$

abstract:
  A simple and yet powerful approach for modeling the structure of endohedrally
confined diatomic molecules is introduced. The theory, based on a u(4)+u(3)
dynamical algebra, combines u(4), the vibron model dynamical algebra, with a
u(3) dynamical algebra that models a spherically symmetric three dimensional
potential. The first algebra encompasses the internal roto-vibrations degrees
of freedom of the molecule, while the second takes into account the confined
molecule center-of-mass degrees of freedom. A resulting subalgebra chain is
connected to the underlying physics and the model is applied to the
prototypical case of H2 caged in a fullerene molecule. The spectrum of the
supramolecular complex H2@C60 is described with a few parameters and
predictions for not yet detected levels are made. Our fits suggest that the
quantum numbers of a few lines should be reassigned to obtain better agreement
with data.


abstract:
  A self-contained derivation of the formalism describing Weyl, Majorana and
Dirac fields from a unified perspective is given based on a concise description
of the representation theory of the proper orthochronous Lorentz group.
Lagrangian methods play no role in the present exposition, which covers several
fundamental aspects of relativistic field theory which are commonly not
included in introductory courses when treating fermionic fields via the Dirac
equation in the first place.


title: Acoustic Localization Phenomena in Ferroelectric Nanophononic Devices

abstract:
  The engineering of phononic resonances in ferroelectric structures appears as
a new knob in the design and realization of novel multifunctional devices. In
this work we experimentally study phononic resonators based on insulating
(BaTiO3, SrTiO3) and metallic (SrRuO3) oxides. We experimentally demonstrate
the confinement of acoustic waves in the 100 GHz frequency range in a phonon
nanocavity, the time and spatial beatings resulting from the coupling of two
different hybrid nanocavities forming an acoustic molecule, and the direct
measurement of Bloch-like oscillations of acoustic phonons in a system formed
by 10 coupled resonators. By means of coherent phonon generation techniques we
study the phonon dynamics directly in the time-domain. The metallic SrRuO3
introduces a local phonon generator and transducer that allows for the spatial,
spectral and time-domain monitoring of the complex generated waves. Our results
introduce ferroelectric cavity systems as a new tool for the study of complex
wave localization phenomena at the nanoscale.


title: Plasmons in a Planar Graphene Superlattice

abstract:
  Plasmon collective excitations are studied in a planar graphene superlattice
formed by periodically alternating regions of gapless graphene and of its
gapped modification. The plasmon dispersion law is determined both for the
quasi-one-dimensional case (the Fermi level is located within the minigap) and
for the quasi-two-dimensional case (the Fermi level is located within the
miniband). The problem concerning the absorption of modulated electromagnetic
radiation at the excitation of plasmons is also considered.


title:
Emergent Structures in an Active Polar Fluid : dynamics of shape,
  scattering and merger

abstract:
  Spatially localised defect structures emerge spontaneously in a hydrodynamic
description of an active polar fluid comprising polar 'actin' filaments and
'myosin' motor proteins that (un)bind to filaments and exert active contractile
stresses. These emergent defect structures are characterized by distinct
textures and can be either static or mobile - we derive effective equations of
motion for these 'extended particles' and analyse their shape, kinetics,
interactions and scattering. Depending on the impact parameter and propulsion
speed, these active defects undergo elastic scattering or merger. Our results
are relevant for the dynamics of actomyosin-dense structures at the cell
cortex, reconstituted actomyosin complexes and 2D active colloidal gels.


title: Band gap engineering of MoS$_2$ upon compression

abstract:
  Molybdenum disulfide (MoS$_2$) is a promising candidate for 2D nanoelectronic
devices, that shows a direct band-gap for monolayer structure. In this work we
study the electronic structure of MoS$_2$ upon both compressive and tensile
strains with first-principles density-functional calculations for different
number of layers. The results show that the band-gap can be engineered for
experimentally attainable strains (i.e. $\pm 0.15$). However compressive strain
can result in bucking that can prevent the use of large compressive strain. We
then studied the stability of the compression, calculating the critical strain
that results in the on-set of buckling for free-standing nanoribbons of
different lengths. The results demonstrate that short structures, or few-layer
MoS$_2$, show semi-conductor to metal transition upon compressive strain
without bucking.


title: Observation of Dirac-Like Semi-Metallic Phase in NdSb

abstract:
  The search of new topological phases of matter is one of the new directions
in condensed matter physics. Recent experimental realizations of Dirac
semimetal phases pave the way to look for other exotic phases of matter in real
materials. Here we present a systematic angle-resolved photoemission
spectroscopy (ARPES) study of NdSb, a potential candidate for hosting a Dirac
semi-metal phase. Our studies reveal two hole-like Fermi surface pockets
present at the zone center ($\Gamma$) point as well as two elliptical
electron-pockets present in the zone corner (X) point of the Brillouin zone
(BZ). Interestingly, Dirac-like linearly dispersive states are observed about
the zone corner (X) point in NdSb. Our first principles calculations agree with
the experimentally observed bands at the $\Gamma$ point. Moreover, the
Dirac-like state observed in NdSb may be a novel correlated state, not yet
predicted in calculations. Our study opens a new direction to look for Dirac
semi-metal states in other members of the rare earth monopnictide family.


title:
The slope, curvature, and higher parameters in $pp$ and $\bar{p}p$
  scattering, and the extrapolation of measurements of $d\sigma(s,t)/dt$ to
  $t=0$

abstract:
  We study the effects of curvature in the expansion of the logarithm of the
differential elastic scattering cross section near $t=0$ as
$d\sigma(s,t)/dt=d\sigma(s,0)/dt\,\times\exp(Bt+Ct^2+Dt^3\cdots)$ in an eikonal
model for $pp$ and $\bar{p}p$ scattering, and use the results to discuss the
extrapolation of measured differential cross sections and the slope parameters
$B$ to $t=-q^2=0$. We find that the curvature effects represented by the
parameters $C$ and $D$, while small, lead to significant changes in the forward
slope parameter relative to that determined in a purely exponential fit, and to
smaller but still significant changes in the forward elastic scattering and
total cross sections. Curvature effects should therefore be considered in
future analyses or reanalyses of the elastic scattering data.


title: Primary Traffic Characterization and Secondary Transmissions

abstract:
  Channel idle time distribution based secondary transmission strategies have
been studied intensively in the literature. Under various performance metrics,
the ultimate performance of secondary devices are eventually dictated by the
presumed channel idle time distribution. Such distributions can take any
arbitrary form in practice. In this work, we study idle time distributions in
wireless local area networks (WLAN) using large amount of the channel idle time
data collected in real-world WLAN networks. We demonstrate with experimental
data that the channel idle time distribution can be closely modeled by
hyper-exponential distribution. Furthermore, one can treat the primary packet
arrival process as a semi-Markov modulated Poisson process. Several secondary
transmission strategies are discussed under this model. It is shown that using
only one hyper-exponential distribution, the secondary user can achieve a
desirable performance when the primary packet arrival process is stationary.
However, experimental data suggests that in practice, this process is not
stationary and the secondary user can experience a large performance loss with
stationary transmission strategy. We propose a novel transmission strategy that
achieves suboptimal secondary user performance when the idle time distribution
is not stationary. The performances of secondary transmission strategies are
demonstrated using experimental data.


title:
Isolating neutrino interactions on hydrogen in composite nuclear targets
  using the T2K Near Detector

abstract:
  An analysis technique for isolating neutrino interactions on hydrogen, from a
target containing a mixture of different nuclei, would provide numerous
benefits. Namely, hydrogen is free of nuclear effects and enables better
reconstruction of the neutrino energy spectra; key for neutrino oscillation
experiments. Presented using Monte Carlo simulations of the ND280 near detector
is the status of such a measurement on v-H resonance production by the T2K
experiment.


title:
Kernel Balancing: A flexible non-parametric weighting procedure for
  estimating causal effects

abstract:
  In the absence of unobserved confounders, matching and weighting methods are
widely used to estimate causal quantities including the Average Treatment
Effect on the Treated (ATT). Unfortunately, these methods do not necessarily
achieve their goal of making the multivariate distribution of covariates for
the control group identical to that of the treated, leaving some (potentially
multivariate) functions of the covariates with different means between the two
groups. When these "imbalanced" functions influence the non-treatment potential
outcome, the conditioning on observed covariates fails, and ATT estimates may
be biased. Kernel balancing, introduced here, targets a weaker requirement for
unbiased ATT estimation, specifically, that the expected non-treatment
potential outcome for the treatment and control groups are equal. The
conditional expectation of the non-treatment potential outcome is assumed to
fall in the space of functions associated with a choice of kernel, implying a
set of basis functions in which this regression surface is linear. Weights are
then chosen on the control units such that the treated and control group have
equal means on these basis functions. As a result, the expectation of the
non-treatment potential outcome must also be equal for the treated and control
groups after weighting, allowing unbiased ATT estimation by subsequent
difference in means or an outcome model using these weights. Moreover, the
weights produced are (1) precisely those that equalize a particular
kernel-based approximation of the multivariate distribution of covariates for
the treated and control, and (2) equivalent to a form of stabilized inverse
propensity score weighting, though it does not require assuming any model of
the treatment assignment mechanism. An R package, KBAL, is provided to
implement this approach.


title:
Robust Solvers for Maxwell's Equations with Dissipative Boundary
  Conditions

abstract:
  In this paper, we design robust and efficient linear solvers for the
numerical approximation of solutions to Maxwell's equations with dissipative
boundary conditions. We consider a structure-preserving finite-element
approximation with standard Nedelec--Raviart--Thomas elements in space and a
Crank--Nicolson scheme in time to approximate the electric and magnetic fields.
  We focus on two types of block preconditioners. The first type is based on
the well-posedness results of the discrete problem. The second uses an exact
block factorization of the linear system, for which the structure-preserving
discretization yields sparse Schur complements. We prove robustness and
optimality of these block preconditioners, and provide supporting numerical
tests.


title: Empirical Likelihood Ratio Test with Distribution Function Constraints

abstract:
  In this work, we study non-parametric hypothesis testing problem with
distribution function constraints. The empirical likelihood ratio test has been
widely used in testing problems with moment (in)equality constraints. However,
some detection problems cannot be described using moment (in)equalities. We
propose a distribution function constraint along with an empirical likelihood
ratio test. This detector is applicable to a wide variety of robust
parametric/non-parametric detection problems. Since the distribution function
constraints provide a more exact description of the null hypothesis, the test
outperforms the empirical likelihood ratio test with moment constraints as well
as many popular goodness-of-fit tests, such as the robust Kolmogorov-Smirnov
test and the Cram\'er-von Mises test. Examples from communication systems with
real-world noise samples are provided to show their performance. Specifically,
the proposed test significantly outperforms the robust Kolmogorov-Smirnov test
and the Cram\'er-von Mises test when the null hypothesis is nested in the
alternative hypothesis. The same example is repeated when we assume no noise
uncertainty. By doing so, we are able to claim that in our case, it is
necessary to include uncertainty in noise distribution. Additionally, the
asymptotic optimality of the proposed test is provided.


title:
Necessary Optimality Conditions for Optimal Control Problems with
  Equilibrium Constraints

abstract:
  This paper introduces and studies the optimal control problem with
equilibrium constraints (OCPEC). The OCPEC is an optimal control problem with a
mixed state and control equilibrium constraint formulated as a complementarity
constraint and it can be seen as a dynamic mathematical program with
equilibrium constraints. It provides a powerful modeling paradigm for many
practical problems such as bilevel optimal control problems and dynamic
principal-agent problems. In this paper, we propose weak, Clarke, Mordukhovich
and strong stationarities for the OCPEC. Moreover, we give some sufficient
conditions to ensure that the local minimizers of the OCPEC are Fritz John type
weakly stationary, Mordukhovich stationary and strongly stationary,
respectively. Unlike Pontryagain's maximum principle for the classical optimal
control problem with equality and inequality constraints, a counter example
shows that for general OCPECs, there may exist two sets of multipliers for the
complementarity constraints. A condition under which these two sets of
multipliers coincide is given.


title: Dynamics of self-interacting strings and energy-momentum conservation

abstract:
  Classical strings coupled to a metric, a dilaton and an axion, as conceived
by superstring theory, suffer from ultraviolet divergences due to
self-interactions. Consequently, as in the case of radiating charged particles,
the corresponding effective string dynamics can not be derived from an action
principle. We propose a fundamental principle to build this dynamics, based on
local energy-momentum conservation in terms of a well-defined
distribution-valued energy-momentum tensor. Its continuity equation implies a
finite equation of motion for self-interacting strings. The construction is
carried out explicitly for strings in uniform motion in arbitrary space-time
dimensions, where we establish cancelations of ultraviolet divergences which
parallel superstring non-renormalization theorems. The uniqueness properties of
the resulting dynamics are analyzed.


title: On Neeman's gradient flows

abstract:
  In his brilliant but sketchy paper on the strucure of quotient varieties of
affine actions of reductive algebraic groups over C, Amnon Neeman introduced a
gradiant flow with remarkable properties. The purpose of this paper is to study
several applications of this flow. In particular we prove that the cone on a
Zariski closed subset of n-1 dimensional real projective space is a deformation
retract of n dimensional Euclidean space. We also give an exposition of an
extension to real reductive algebraic group actions of Schwarz's excellent
explanation of Neeman's sketch of a proof of his deformation theorem. This
exposition precisely explains the use of Lojasiewicz gradient inequality. The
result described above for cones makes use of these ideas.


title:
Electric dipole moment of the deuteron in the standard model with $NN -
  \Lambda N - \Sigma N$ coupling

abstract:
  We calculate the electric dipole moment (EDM) of the deuteron in the standard
model with $|\Delta S| =1$ interactions by taking into account the $NN -
\Lambda N - \Sigma N$ channel coupling, which is an important nuclear level
systematics. The two-body problem is solved with the Gaussian Expansion Method
using the realistic Argonne $v18$ nuclear force and the $YN$ potential which
can reproduce the binding energies of $^3_\Lambda$H, $^3_\Lambda$He, and
$^4_\Lambda$He. The $|\Delta S| =1$ interbaryon potential is modeled by the
one-meson exchange process. It is found that the deuteron EDM is modified by
less than 10\%, and the main contribution to this deviation is due to the
polarization of the hyperon-nucleon channels. The effect of the $YN$
interaction is small, and treating $ \Lambda N$ and $ \Sigma N$ channels as
free is a good approximation for the EDM of the deuteron.


title:
Fractional smoothness of images of logarithmically concave measures
  under polynomials

abstract:
  We show that a measure on the real line that is the image of a log-concave
measure under a polynomial of degree $d$ possesses a density from the
Nikol'skii--Besov class of fractional order $1/d$. This result is used to prove
an estimate of the total variation distance between such measures in terms of
the Fortet--Mourier distance.


title:
Lowering IceCube's Energy Threshold for Point Source Searches in the
  Southern Sky

abstract:
  Observation of a point source of astrophysical neutrinos would be a "smoking
gun" signature of a cosmic-ray accelerator. While IceCube has recently
discovered a diffuse flux of astrophysical neutrinos, no localized point source
has been observed. Previous IceCube searches for point sources in the southern
sky were restricted by either an energy threshold above a few hundred TeV or
poor neutrino angular resolution. Here we present a search for southern sky
point sources with greatly improved sensitivities to neutrinos with energies
below 100 TeV. By selecting charged-current $\nu_{\mu}$ interacting inside the
detector, we reduce the atmospheric background while retaining efficiency for
astrophysical neutrino-induced events reconstructed with sub-degree angular
resolution. The new event sample covers three years of detector data and leads
to a factor of ten improvement in sensitivity to point sources emitting below
100 TeV in the southern sky. No statistically significant evidence of point
sources was found, and upper limits are set on neutrino emission from
individual sources. A posteriori analysis of the highest-energy ~100 TeV
starting event in the sample found that this event alone represents a
$2.8\sigma$ deviation from the hypothesis that the data consists only of
atmospheric background.


title:
Look-ahead before you leap: end-to-end active recognition by forecasting
  the effect of motion

abstract:
  Visual recognition systems mounted on autonomous moving agents face the
challenge of unconstrained data, but simultaneously have the opportunity to
improve their performance by moving to acquire new views of test data. In this
work, we first show how a recurrent neural network-based system may be trained
to perform end-to-end learning of motion policies suited for this "active
recognition" setting. Further, we hypothesize that active vision requires an
agent to have the capacity to reason about the effects of its motions on its
view of the world. To verify this hypothesis, we attempt to induce this
capacity in our active recognition pipeline, by simultaneously learning to
forecast the effects of the agent's motions on its internal representation of
the environment conditional on all past views. Results across two challenging
datasets confirm both that our end-to-end system successfully learns meaningful
policies for active category recognition, and that "learning to look ahead"
further boosts recognition performance.


title:
Beurling densities and frames of exponentials on the union of small
  balls

abstract:
  If $x_1,\dots,x_m$ are finitely many points in $\mathbb{R}^d$, let
$E_\epsilon=\cup_{i=1}^m\,x_i+Q_\epsilon$, where $Q_\epsilon=\{x\in
\mathbb{R}^d,\,\,|x_i|\le \epsilon/2, \, i=1,...,d\}$ and let $\hat f$ denote
the Fourier transform of $f$. Given a positive Borel measure $\mu$ on
$\mathbb{R}^d$, we provide a necessary and sufficient condition for the frame
inequalities $$ A\,\|f\|^2_2\le \int_{\mathbb{R}^d}\,|\hat
f(\xi)|^2\,d\mu(\xi)\le B\,\|f\|^2_2,\quad f\in L^2(E_\epsilon), $$ to hold for
some $A,B>0$ and for some $\epsilon>0$ sufficiently small. If $m=1$, we show
that the limits of the optimal lower and upper frame bounds as
$\epsilon\rightarrow 0$ are equal, respectively, to the lower and upper
Beurling density of $\mu$. When $m>1$, we extend this result by defining a
matrix version of Beurling density. Given a (possibly dense) subgroup $G$ of
$\mathbb{R}$, we then consider the problem of characterizing those measures
$\mu$ for which the inequalities above hold whenever $x_1,\dots,x_m$ are
finitely many points in $G$ (with $\epsilon$ depending on those points, but not
$A$ or $B$). We point out an interesting connection between this problem and
the notion of well-distributed sequence when $G=a\,\mathbb{Z}$ for some $a>0$.
Finally, we show the existence of a discrete set $\Lambda$ such that the
measure $\mu=\sum_{\lambda}\,\delta_\lambda$ satisfy the property above for the
whole group $\mathbb{R}$.


title: Dynamical centrosymmetry breaking in graphene

abstract:
  We discover an unusual phenomenon that occurs when a graphene monolayer is
illuminated by a short and intense pulse at normal incidence. Due to the
pulse-induced oscillations of the Dirac cones, a dynamical breaking of the
layer's centrosymmetry takes place, leading to the generation of second
harmonic waves. We prove that this result can only be found by using the full
Dirac equation and show that the widely used semiconductor Bloch equations fail
to reproduce this and some other important physics of graphene. Our results
open new windows in the understanding of nonlinear light-matter interactions in
a wide variety of new 2D materials with a gapped or ungapped Dirac-like
dispersion.


title: Approximating Nash Equilibrium Via Multilinear Minimax

abstract:
  Nash equilibrium} (NE) can be stated as a formal theorem on a multilinear
form, free of game theory terminology. On the other hand, inspired by this
formalism, we state and prove a {\it multilinear minimax theorem}, a
generalization of von Neumann's bilinear minimax theorem. As in the bilinear
case, the proof is based on relating the underlying optimizations to a
primal-dual pair of linear programming problems, albeit more complicated LPs.
The theorem together with its proof is of independent interest. Next, we use
the theorem to associate to a multilinear form in NE a {\it multilinear minimax
relaxation} (MMR), where the primal-dual pair of solutions induce an
approximate equilibrium point that provides a nontrivial upper bound on a
convex combination of {\it expected payoffs} in any NE solution. In fact we
show any positive probability vector associated to the players induces a
corresponding {\it diagonally-scaled} MMR approximate equilibrium with its
associated upper bound. By virtue of the proof of the multilinear minimax
theorem, MMR solution can be computed in polynomial-time. On the other hand, it
is known that even in bimatrix games NE is {\it PPAD-complete}, a complexity
class in NP not known to be in P. The quality of MMR solution and the
efficiency of solving the underlying LPs are the subject of further
investigation. However, as shown in a separate article, for a large set of test
problems in bimatrix games, not only the MMR payoffs for both players are
better than any NE payoffs, so is the computing time of MMR in contrast with
that of Lemke-Howsen algorithm. In large size problems the latter algorithm
even fails to produce a Nash equilibrium. In summary, solving MMR provides a
worthy approximation even if Nash equilibrium is shown to be computable in
polynomial-time.


title: Homogenization of pathwise Hamilton-Jacobi equations

abstract:
  We present qualitative and quantitative homogenization results for pathwise
Hamilton-Jacobi equations with "rough" multiplicative driving signals. When
there is only one such signal and the Hamiltonian is convex, we show that the
equation, as well as equations with smooth approximating paths, homogenize. In
the multi-signal setting, we demonstrate that blow-up or homogenization may
take place. The paper also includes a new well-posedness result, which gives
explicit estimates for the continuity of the solution map and the
equicontinuity of solutions in the spatial variable.


title: Configuration Lattices for Planar Contact Manipulation Under Uncertainty

abstract:
  This work addresses the challenge of a robot using real-time feedback from
contact sensors to reliably manipulate a movable object on a cluttered
tabletop. We formulate contact manipulation as a partially observable Markov
decision process (POMDP) in the joint space of robot configurations and object
poses. The POMDP formulation enables the robot to actively gather information
and reduce the uncertainty on the object pose. Further, it incorporates all
major constraints for robot manipulation: kinematic reachability,
self-collision, and collision with obstacles. To solve the POMDP, we apply
DESPOT, a state-of-the-art online POMDP algorithm. Our approach leverages two
key ideas for computational efficiency. First, it performs lazy construction of
a configuration-space lattice by interleaving construction of the lattice and
online POMDP planning. Second, it combines online and offline POMDP planning by
solving relaxed POMDP offline and using the solution to guide the online search
algorithm. We evaluated the proposed approach on a seven degree-of-freedom
robot arm in simulation environments. It significantly outperforms several
existing algorithms, including some commonly used heuristics for contact
manipulation under uncertainty.


title:
Enforcing Template Representability and Temporal Consistency for
  Adaptive Sparse Tracking

abstract:
  Sparse representation has been widely studied in visual tracking, which has
shown promising tracking performance. Despite a lot of progress, the visual
tracking problem is still a challenging task due to appearance variations over
time. In this paper, we propose a novel sparse tracking algorithm that well
addresses temporal appearance changes, by enforcing template representability
and temporal consistency (TRAC). By modeling temporal consistency, our
algorithm addresses the issue of drifting away from a tracking target. By
exploring the templates' long-term-short-term representability, the proposed
method adaptively updates the dictionary using the most descriptive templates,
which significantly improves the robustness to target appearance changes. We
compare our TRAC algorithm against the state-of-the-art approaches on 12
challenging benchmark image sequences. Both qualitative and quantitative
results demonstrate that our algorithm significantly outperforms previous
state-of-the-art trackers.


title: Uranus evolution models with simple thermal boundary layers

abstract:
  The strikingly low luminosity of Uranus (Teff ~ Teq) constitutes a
long-standing challenge to our understanding of Ice Giant planets. Here we
present the first Uranus structure and evolution models that are constructed to
agree with both the observed low luminosity and the gravity field data. Our
models make use of modern ab initio equations of state at high pressures for
the icy components water, methane, and ammonia. Proceeding step by step, we
confirm that adiabatic models yield cooling times that are too long, even when
uncertainties in the ice:rock ratio (I:R) are taken into account. We then argue
that the transition between the ice/rock-rich interior and the H/He-rich outer
envelope should be stably stratified. Therefore, we introduce a simple thermal
boundary and adjust it to reproduce the low luminosity. Due to this thermal
boundary, the deep interior of the Uranus models are up to 2--3 warmer than
adiabatic models, necessitating the presence of rocks in the deep interior with
a possible I:R of $1\times$ solar. Finally, we allow for an equilibrium
evolution (Teff ~ Teq) that begun prior to the present day, which would
therefore no longer require the current era to be a "special time" in Uranus'
evolution. In this scenario, the thermal boundary leads to more rapid cooling
of the outer envelope. When Teff ~ Teq is reached, a shallow, subadiabatic zone
in the atmosphere begins to develop. Its depth is adjusted to meet the
luminosity constraint. This work provides a simple foundation for future Ice
Giant structure and evolution models, that can be improved by properly treating
the heat and particle fluxes in the diffusive zones.


title: On the number of Singular Vector Tuples of Hyper-Cubical Tensors

abstract:
  Shmuel Friedland and Giorgio Ottaviani's beautiful constant term expression
for the number of singular vector tuples of generic tensors is used to derive a
rational generating function for these numbers, that in turn, is used to obtain
an asymptotic formula for the number of such tuples for n by n by n
three-dimensional tensors, and to conjecture an asymptotic formula for the
general d-dimensional case. A donation of 100 dollars, in honor of the first
prover, will be made to the On-line Encyclopedia of Integer Sequences.


title: Robustness of mathematical models and technical analysis strategies

abstract:
  The aim of this paper is to compare the performances of the optimal strategy
under parameters mis-specification and of a technical analysis trading
strategy. The setting we consider is that of a stochastic asset price model
where the trend follows an unobservable Ornstein-Uhlenbeck process. For both
strategies, we provide the asymptotic expectation of the logarithmic return as
a function of the model parameters. Finally, numerical examples find that an
investment strategy using the cross moving averages rule is more robust than
the optimal strategy under parameters mis-specification.


title: Reduction Operators and Completion of Rewriting Systems

abstract:
  We propose a functional description of rewriting systems where reduction
rules are represented by linear maps called reduction operators. We show that
reduction operators admit a lattice structure. Using this structure we define
the notion of confluence and we show that this notion is equivalent to the
Church-Rosser property of reduction operators. In this paper we give an
algebraic formulation of completion using the lattice structure. We relate
reduction operators and Gr\"obner bases. Finally, we introduce generalised
reduction operators relative to non total ordered sets.


title:
Orbital disproportionation of electronic density - a universal feature
  of alkali-doped fullerides

abstract:
  Alkali-doped fullerides A$_n$C$_{60}$ show a remarkably wide range of
electronic phases in function of A= Li, Na, K, Rb, Cs and the degree of doping,
$n=1-5$. While the presence of strong electron correlations is well
established, recent investigations give also evidence for dynamical Jahn-Teller
instability in the insulating and the metallic phase of A$_3$C$_{60}$. To
reveal the interplay of these interactions in fullerides with even $n$, we
address the electronic phase of A$_4$C$_{60}$ with accurate many-body
calculations within a realistic electronic model including all basic
interactions extracted from first principles. We find that the Jahn-Teller
instability is always realized in these materials too. More remarkably, in
sharp contrast to strongly correlated A$_3$C$_{60}$, A$_4$C$_{60}$ displays
uncorrelated band-insulating state despite pretty similar interactions present
in both fullerides. Our results show that the Jahn-Teller instability and the
accompanying orbital disproportionation of electronic density in the degenerate
LUMO band is a universal feature of fullerides.