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arxiv_dataset-112001905.01564 | Effective aspect ratio of helices in shear flow
cond-mat.soft
We report the results of simulations of rigid colloidal helices suspended in
a shear flow, using dissipative particle dynamics for a coarse-grained
representation of the suspending fluid, as well as deterministic trajectories
of non-Brownian helices calculated from the resistance tensor derived under the
slender-body approximation. The shear flow produces nonuniform rotation of the
helices, similarly to other high aspect ratio particles, such that more
elongated helices spend more time aligned with the fluid velocity. We introduce
a geometric effective aspect ratio calculated directly from the helix geometry
and a dynamical effective aspect ratio derived from the trajectories of the
particles and find that the two effective aspect ratios are approximately equal
over the entire parameter range tested. We also describe observed transient
deflections of the helical axis into the vorticity direction that can occur
when the helix is rotating through the gradient direction and that depend on
the rotation of the helix about its axis.
| arxiv topic:cond-mat.soft |
arxiv_dataset-112011905.01664 | Recognizing shape via 1st eigenvalue, mean curvature and upper curvature
bound
math.DG math.MG
Let $M^n$ be a closed immersed hypersurface lying in a contractible ball
$B(p,R)$ of the ambient $(n+1)$-manifold $N^{n+1}$. We prove that, by pinching
Heintze-Reilly's inequality via sectional curvature upper bound of $B(p,R)$,
1st eigenvalue and mean curvature of $M$, not only $M$ is Hausdorff close to a
geodesic sphere $S(p_0,R_0)$ in $N$, but also the ``enclosed'' ball
$B(p_0,R_0)$ is close to be of constant curvature, provided with a uniform
control on the volume and mean curvature of $M$. We raise a conjecture for $M$
to be a diffeomorphic sphere, and give some positive partial answer.
| arxiv topic:math.DG math.MG |
arxiv_dataset-112021905.01764 | Continuous monitoring measured signals bounded by past and future
conditions in enlarged quantum systems
quant-ph
In a quantum system that is bounded by past and future conditions, weak
continuous monitoring forward-evolving and backward-evolving quantum states are
usually carried out separately. Therefore, measured signals at a given time t
cannot be monitored continuously. Here, we propose an enlarged-quantum-system
method to combine these two processes together. Therein, we introduce an
enlarged quantum state that contains both the forward- and backward-evolving
quantum states. The enlarged state is governed by an enlarged master equation
and propagates one-way forward in time. As a result, the measured signals at
time t can be monitored continuously and can provide advantages in the signals
amplification and signal processing techniques. Our proposal can be implemented
on various physical systems, such as superconducting circuits, NMR systems,
ion-traps, quantum photonics, and among others.
| arxiv topic:quant-ph |
arxiv_dataset-112031905.01864 | A supercritical Sobolev type inequality in higher order Sobolev spaces
and related higher order elliptic problems
math.AP math.CA math.FA
A Sobolev type embedding for radially symmetric functions on the unit ball
$B$ in $\mathbb R^n$, $n\geq 3$, into the variable exponent Lebesgue space
$L_{2^\star + |x|^\alpha} (B)$, $2^\star = 2n/(n-2)$, $\alpha>0$, is known due
to J.M. do \'O, B. Ruf, and P. Ubilla, namely, the inequality \[
\sup\Big\{\int_B |u(x)|^{2^\star+|x|^\alpha} dx : u\in H^1_{0,{\rm rad}}(B),
\|\nabla u\|_{L^2(B)} =1\Big\} < +\infty
\] holds. In this work, we generalize the above inequality for higher order
Sobolev spaces of radially symmetric functions on $B$, namely, the embedding \[
H^m_{0,{\rm rad}}(B) \hookrightarrow L_{2_m^\star + |x|^\alpha} (B) \] with
$2\leq m < n/2$, $2_m^* = 2n/(n-2m)$, and $\alpha>0$ holds. Questions
concerning the sharp constant for the inequality including the existence of the
optimal functions are also studied. To illustrate the finding, an application
to a boundary value problem on balls driven by polyharmonic operators is
presented. This is the first in a set of our works concerning functional
inequalities in the supercritical regime.
| arxiv topic:math.AP math.CA math.FA |
arxiv_dataset-112041905.01964 | Neural Chinese Named Entity Recognition via CNN-LSTM-CRF and Joint
Training with Word Segmentation
cs.CL cs.LG stat.ML
Chinese named entity recognition (CNER) is an important task in Chinese
natural language processing field. However, CNER is very challenging since
Chinese entity names are highly context-dependent. In addition, Chinese texts
lack delimiters to separate words, making it difficult to identify the boundary
of entities. Besides, the training data for CNER in many domains is usually
insufficient, and annotating enough training data for CNER is very expensive
and time-consuming. In this paper, we propose a neural approach for CNER.
First, we introduce a CNN-LSTM-CRF neural architecture to capture both local
and long-distance contexts for CNER. Second, we propose a unified framework to
jointly train CNER and word segmentation models in order to enhance the ability
of CNER model in identifying entity boundaries. Third, we introduce an
automatic method to generate pseudo labeled samples from existing labeled data
which can enrich the training data. Experiments on two benchmark datasets show
that our approach can effectively improve the performance of Chinese named
entity recognition, especially when training data is insufficient.
| arxiv topic:cs.CL cs.LG stat.ML |
arxiv_dataset-112051905.02064 | The effect of intermittent upwelling events on plankton blooms
q-bio.PE nlin.CD
In the marine environment biological processes are strongly affected by
oceanic currents, particularly by eddies (vortices) formed by the hydrodynamic
flow field. Employing a kinematic flow field coupled to a population dynamical
model for plankton growth, we study the impact of an intermittent upwelling of
nutrients on triggering harmful algal blooms (HABs). Though it is widely
believed that additional nutrients boost the formation of HABs or algal blooms
in general, we show that the response of the plankton to nutrient plumes
depends crucially on the mesoscale hydrodynamic flow structure. In general
nutrients can either be quickly washed out from the observation area, or can be
captured by the vortices in the flow. The occurrence of either scenario depends
on the relation between the time scales of the vortex formation and nutrient
upwelling as well as the time instants at which upwelling pulse occurs and how
long do they last. We show that these two scenarios result in very different
responses in plankton dynamics which makes it very difficult to predict,
whether nutrient upwelling will lead to a HAB or not. This explains, why
observational data are sometimes inconclusive establishing a correlation
between upwelling events and plankton blooms.
| arxiv topic:q-bio.PE nlin.CD |
arxiv_dataset-112061905.02164 | Optimization of infinite projected entangled pair states: The role of
multiplets and their breaking
cond-mat.str-el
The infinite projected entangled pair states (iPEPS) technique [J. Jordan
{\it et al.}, Phys. Rev. Lett. {\bf 101}, 250602 (2008)] has been widely used
in the recent years to assess the properties of two-dimensional quantum
systems, working directly in the thermodynamic limit. This formalism, which is
based upon a tensor-network representation of the ground-state wave function,
has several appealing features, e.g., encoding the so-called area law of
entanglement entropy by construction; still, the method presents critical
issues when dealing with the optimization of tensors, in order to find the best
possible approximation to the exact ground state of a given Hamiltonian. Here,
we discuss the obstacles that arise in the optimization by imaginary-time
evolution within the so-called simple and full updates and connect them to the
emergence of a sharp multiplet structure in the "virtual" indices of tensors.
In this case, a generic choice of the bond dimension $D$ is not compatible with
the multiplets and leads to a symmetry breaking (e.g., generating a finite
magnetic order). In addition, varying the initial guess, different final states
may be reached, with very large deviations in the magnetization value. In order
to exemplify this behavior, we show the results of the $S=1/2$ Heisenberg model
on an array of coupled ladders, for which a vanishing magnetization below the
critical interladder coupling is recovered only for selected values of $D$,
while a blind optimization with a generic $D$ gives rise to a finite
magnetization down to the limit of decoupled ladders.
| arxiv topic:cond-mat.str-el |
arxiv_dataset-112071905.02264 | Stable multivariate generalizations of matching polynomials
math.CO
The first part of this note concerns stable averages of multivariate matching
polynomials. In proving the existence of infinite families of bipartite
Ramanujan $d$-coverings, Hall, Puder and Sawin introduced the $d$-matching
polynomial of a graph $G$, defined as the uniform average of matching
polynomials over the set of $d$-sheeted covering graphs of $G$. We prove that a
natural multivariate version of the $d$-matching polynomial is stable,
consequently giving a short direct proof of the real-rootedness of the
$d$-matching polynomial. Our theorem also includes graphs with loops, thus
answering a question of said authors. Furthermore we define a weaker notion of
matchings for hypergraphs and prove that a family of natural polynomials
associated to such matchings are stable. In particular this provides a
hypergraphic generalization of the classical Heilmann-Lieb theorem.
| arxiv topic:math.CO |
arxiv_dataset-112081905.02364 | Conjectures on the distribution of roots modulo a prime of a polynomial
math.NT
For a given monic integral polynomial $f(x)$ of degree $n$, we define local
roots $r_i$ of $f(x)$ for a completely decomposable prime $p$ by $r_i \in
\mathbb{Z}$, $f(r_i) \equiv 0 \bmod p$ and $0 \le r_1 \le r_2 \le \dots \le r_n
< p$. With numerical data, we propose a conjecture on the distribution of
$(r_1/p,\dots,r_n/p)$, which is a new kind of equi-distribution, and a
conjecture of the distribution of $(r_1,\dots,r_n)$ which satisfies $r_i \equiv
R_i \bmod L$ for given natural numbers $L,R_1,\dots,R_n$, which is nothing but
Dirichlet's theorem on an arithmetic progression in the case $n = 1$.
| arxiv topic:math.NT |
arxiv_dataset-112091905.02464 | Authorship analysis of specialized vs diversified research output
cs.DL
The present work investigates the relations between amplitude and type of
collaboration (intramural, extramural domestic or international) and output of
specialized versus diversified research. By specialized or diversified
research, we mean within or beyond the author's dominant research topic. The
field of observation is the scientific production over five years from about
23,500 academics. The analyses are conducted at the aggregate and disciplinary
level. The results lead to the conclusion that in general, the output of
diversified research is no more frequently the fruit of collaboration than is
specialized research. At the level of the particular collaboration types,
international collaborations weakly underlie the specialized kind of research
output; on the contrary, extramural domestic and intramural collaborations are
weakly associated with diversified research. While the weakness of association
remains, exceptions are observed at the level of the individual disciplines.
| arxiv topic:cs.DL |
arxiv_dataset-112101905.02564 | Sensitivity measuring expected on the electromagnetic anomalous
couplings in the $t\bar t\gamma$ vertex at the FCC-he
hep-ph
In this paper, we consider the electroweak production cross-section of a
single anti-top-quark, a neutrino and a photon via charged current through the
$e^-p \to e^-\bar b \to \bar t \nu_e \gamma \to \bar t(\to W^- \to (qq', l^-
\bar\nu_l)+b) \nu_e\gamma$ signal. Further, we derived the sensitivity expected
to the magnetic dipole moment $(\hat a_V)$ and the electric dipole moment
$(\hat a_A)$ of the top-quark at the Future Circular Collider Hadron Electron
(FCC-he). We present our study for $\sqrt{s}=7.07, 10\hspace{0.8mm}TeV$, ${\cal
L}=50, 100, 300, 500, 1000\hspace{0.8mm}fb^{-1}$, $\delta_{sys}=0, 3,
5\hspace{0.8mm}\%$ and $P_{e^-}=0\%, 80\%, -80\%$, respectively. We find that
the sensitivity estimated on dipole moments of the top-quark is of the order of
magnitude ${\cal O}(10^{-1})$ for both hadronic and leptonic decay modes of
$W^-$: $\hat a_V=[-0.2308, 0.2204]$, $|\hat a_A|=0.2259$ at $95\%$ C.L. in the
hadronic channel with unpolarized electron beam $P_{e^-}=0\%$. Our results with
polarized electron beam for $P_{e^-}=80\%$ and $P_{e^-}=-80\%$ are $\hat
a_V=[-0.3428, 0.3321]$, $|\hat a_A|=0.3371$ and $\hat a_V=[-0.2041, 0.1858]$,
$|\hat a_A|=0.1939$ at $95\%$ C.L. in the hadronic channel. The corresponding
results for the leptonic channel with $P_{e^-}=0\%, 80\% -80\%$ are $\hat
a_V=[-0.3067, 0.2963]$, $|\hat a_A|=0.3019$, $\hat a_V=[-0.4563, 0.4456]$,
$|\hat a_A|=0.4505$ and $\hat a_V=[-0.2695, 0.2512]$, $|\hat a_A|=0.2592$,
respectively. The results for $\hat a_V$ and $\hat a_A$ in the leptonic channel
are weaker by a factor of 0.75 than those corresponding to the hadronic
channel. Given these prospective sensitivities we highlight that the FCC-he is
potential top-quark factory that is particularly well suited to sensitivity
study on its dipole moments and with cleaner environments.
| arxiv topic:hep-ph |
arxiv_dataset-112111905.02664 | Equivariant holonomy of U(1)-bundles
math.DG
We define the equivariant holonomy of an invariant connection on a principal
U(1)-bundle. The properties of the ordinary holonomy are generalized to the
equivariant setting. In particular, equivariant U(1)-bundles with connection
are shown to be classified by its equivariant holonomy modulo isomorphisms. We
also show that the equivariant holonomy can be used to obtain results about
equivariant prequantization and anomaly cancellation.
| arxiv topic:math.DG |
arxiv_dataset-112121905.02764 | Partial data inverse problems and simultaneous recovery of boundary and
coefficients for semilinear elliptic equations
math.AP
We study various partial data inverse boundary value problems for the
semilinear elliptic equation $\Delta u+ a(x,u)=0$ in a domain in $\mathbb R^n$
by using the higher order linearization technique introduced in [LLS 19, FO19].
We show that the Dirichlet-to-Neumann map of the above equation determines the
Taylor series of $a(x,z)$ at $z=0$ under general assumptions on $a(x,z)$. The
determination of the Taylor series can be done in parallel with the detection
of an unknown cavity inside the domain or an unknown part of the boundary of
the domain. The method relies on the solution of the linearized partial data
Calder\'on problem [FKSU09], and implies the solution of partial data problems
for certain semilinear equations $\Delta u+ a(x,u) = 0$ also proved in [KU19].
The results that we prove are in contrast to the analogous inverse problems
for the linear Schr\"odinger equation. There recovering an unknown cavity (or
part of the boundary) and the potential simultaneously are long-standing open
problems, and the solution to the Calder\'on problem with partial data is known
only in special cases when $n \geq 3$.
| arxiv topic:math.AP |
arxiv_dataset-112131905.02864 | M\"obius Disjointness for Nilsequences Along Short Intervals
math.DS math.NT
For a nilmanifold $G/\Gamma$, a $1$-Lipschitz continuous function $F$ and the
M\"obius sequence $\mu(n)$, we prove a bound on the decay of the averaged short
interval correlation $$\frac1{HN}\sum_{n\leq N}\Big|\sum_{h\leq H}
\mu(n+h)F(g^{n+h}x)\Big|$$ as $H,N\to\infty$. The bound is uniform in $g\in G$,
$x\in G/\Gamma$ and $F$.
| arxiv topic:math.DS math.NT |
arxiv_dataset-112141905.02964 | Database support of detector operation and data analysis in the
DEAP-3600 Dark Matter experiment
physics.ins-det
The DEAP-3600 detector searches for dark matter interactions on a 3.3 tonne
liquid argon target. Over nearly a decade, from start of detector construction
through the end of the data analysis phase, well over 200 scientists will have
contributed to the project. The DEAP-3600 detector will amass in excess of 900
TB of data representing more than 10$^{10}$ particle interactions, a few of
which could be from dark matter. At the same time, metadata exceeding 80 GB
will be generated. This metadata is crucial for organizing and interpreting the
dark matter search data and contains both structured and unstructured
information.
The scale of the data collected, the important role of metadata in
interpreting it, the number of people involved, and the long lifetime of the
project necessitate an industrialized approach to metadata management.
We describe how the CouchDB and the PostgreSQL database systems were
integrated into the DEAP detector operation and analysis workflows. This
integration provides unified, distributed access to both structured
(PostgreSQL) and unstructured (CouchDB) metadata at runtime of the data
analysis software. It also supports operational and reporting requirements.
| arxiv topic:physics.ins-det |
arxiv_dataset-112151905.03064 | Cellular Coverage-Aware Path Planning for UAVs
eess.SP
Up until now, path planning for unmanned aerial vehicles (UAVs) has mainly
been focused on the optimisation towards energy efficiency. However, to operate
UAVs safely, wireless coverage is of utmost importance. Currently, deployed
cellular networks often exhibit an inadequate performance for aerial users due
to high amounts of intercell interference. Furthermore, taking the never-ending
trend of densification into account, the level of interference experienced by
UAVs will only increase in the future. For the purpose of UAV trajectory
planning, wireless coverage should be taken into account to mitigate
interference and to lower the risk of dangerous connectivity outages. In this
paper, several path planning strategies are proposed and evaluated to optimise
wireless coverage for UAVs. A simulator using a real-life 3D map is used to
evaluate the proposed algorithms for both 4G and 5G scenarios. We show that the
proposed Coverage-Aware A* algorithm, which alters the UAV's flying altitude,
is able to improve the mean SINR by 3-4dB and lower the cellular outage
probability by a factor of 10. Furthermore, the outages that still occur have a
60% shorter length, hence posing a lower risk to induce harmful accidents.
| arxiv topic:eess.SP |
arxiv_dataset-112161905.03164 | Stabilized energy factorization approach for Allen-Cahn equation with
logarithmic Flory-Huggins potential
physics.comp-ph math.NA
The Allen--Cahn equation is one of fundamental equations of phase-field
models, while the logarithmic Flory--Huggins potential is one of the most
useful energy potentials in various phase-field models. In this paper, we
consider numerical schemes for solving the Allen--Cahn equation with
logarithmic Flory--Huggins potential. The main challenge is how to design
efficient numerical schemes that preserve the maximum principle and energy
dissipation law due to the strong nonlinearity of the energy potential
function. We propose a novel energy factorization approach with the stability
technique, which is called stabilized energy factorization approach, to deal
with the Flory--Huggins potential. One advantage of the proposed approach is
that all nonlinear terms can be treated semi-implicitly and the resultant
numerical scheme is purely linear and easy to implement. Moreover, the discrete
maximum principle and unconditional energy stability of the proposed scheme are
rigorously proved using the discrete variational principle. Numerical results
are presented to demonstrate the stability and effectiveness of the proposed
scheme.
| arxiv topic:physics.comp-ph math.NA |
arxiv_dataset-112171905.03264 | Superconducting gap anisotropy and topological singularities due to
lattice translational symmetry and their thermodynamic signatures
cond-mat.supr-con cond-mat.str-el
Symmetry arguments based on the point group of a system and thermodynamic
measurements are often combined to identify the order parameter in
unconventional superconductors. However, lattice translations, which can induce
additional momenta with vanishing order parameter in the Brillouin zone, are
neglected, especially in gap functions otherwise expected to be constant, such
as in chiral superconductors. After a general analysis of the symmetry
conditions for vanishing gap functions, we study the case of chiral $p$- and
chiral $f$-wave pairing on a square lattice, a situation relevant for
Sr$_2$RuO$_4$. Specifically, we calculate the impurity-induced density of
states, specific heat, superfluid density and thermal conductivity employing a
self-consistent T-matrix calculation and compare our results to the case of a
nodal ($d$-wave) order parameter. While there is a clear distinction between a
fully gapped chiral state and a nodal state, the strongly anisotropic case is
almost indistinguishable from the nodal case. Our findings illustrate the
difficulty of interpreting thermodynamic measurements. In particular, we find
that the available measurements are consistent with a chiral ($f$-wave) order
parameter. Our results help to reconcile the thermodynamic measurements with
the overall picture of chiral spin-triplet superconductivity in Sr$_2$RuO$_4$.
| arxiv topic:cond-mat.supr-con cond-mat.str-el |
arxiv_dataset-112181905.03364 | Gaudin model modulo $p$, Tango structures, and dormant Miura opers
math.AG
In the present paper, we study the Bethe ansatz equations for Gaudin model
and Miura opers in characteristic $p>0$. Our study is based on a work by E.
Frenkel, in which solutions to the Bethe ansatz equations are described in
terms of Miura opers on the complex projective line. The main result of the
present paper provides a positive characteristic analogue of this description.
We pay particular attention to the case of Miura $\mathrm{PGL}_2$-opers because
dormant generic Miura $\mathrm{PGL}_2$-opers correspond bijectively to Tango
structures, which bring various sorts of exotic phenomena in positive
characteristic, e.g., counter-examples to the Kodaira vanishing theorem. As a
consequence, we construct new examples of Tango structures by means of
solutions to the Bethe ansatz equations modulo $p$.
| arxiv topic:math.AG |
arxiv_dataset-112191905.03464 | Real-time measurement with a fiber optical surface plasmon resonance
sensor for biochemical interaction analysis
physics.app-ph
In this paper we report a fiber optical sensor system based on surface
plasmon resonance (SPR) with real-time response for biochemical interaction
analysis. The fiber sensor is constructed from a multi-mode fiber with plastic
cladding. To facilitate the measurement, a software program is developed which
integrates the data acquisition and processing for real-time feedback.
Polynomial fitting is implemented to smooth out the noise in the transmission
ratio and a spectral resolution of 0.2 nm is achieved. Ethyl alcohol and water
mixtures with different concentrations are measured to demonstrate the system's
real-time capability. This work is essential for the development of a compact,
real-time fiber SPR biosensor.
| arxiv topic:physics.app-ph |
arxiv_dataset-112201905.03564 | Local flux-flow instability in superconducting films near Tc
cond-mat.supr-con
Larkin and Ovchinnikov established that the viscous flow of magnetic flux
quanta in current-biased superconductor films placed in a perpendicular
magnetic field can lose stability due to a decrease in the vortex viscosity
coefficient $\eta$ with increasing velocity of the vortices $v$. The dependence
of $\eta$ on $v$ leads to a $nonlinear$ section in the current-voltage
($I$-$V$) curve which ends at the flux-flow instability point with a voltage
jump to a highly resistive state. At the same time, in contradistinction with
the nonlinear conductivity regime, instability jumps often occur in $linear$
$I$-$V$ sections. Here, for the elucidation of such jumps we develop a theory
of local instability of the magnetic flux flow occurring not in the entire film
but in a narrow strip across the film width in which vortices move much faster
than outside it. The predictions of the developed theory are in agreement with
experiments on Nb films for which the heat removal coefficients and the
inelastic scattering times of quasiparticles are deduced. The presented model
of local instability is also relevant for the characterization of
superconducting thin films whose performance is examined for fast single-photon
detection.
| arxiv topic:cond-mat.supr-con |
arxiv_dataset-112211905.03664 | Characterization of vorticity in pygmy resonances and soft-dipole modes
with two-nucleon transfer reactions
nucl-th
The properties of the two-quasiparticle-like soft E1-modes and PDR have been
and are systematically studied with the help of inelastic and electromagnetic
experiments which essentially probe the particle-hole components of these
vibrations. It is shown that further insight in their characterisation can be
achieved with the help of two-nucleon transferreactions, in particular
concerning the particle-particle components of the modes, in terms of absolute
differential cross sections which take properly into account successive and
simultaneous transfer mechanisms corrected for non-orthogonality, able to
reproduce the experimental findings at the 10% level. The process
$^9$Li$(t,p)^{11}$Li(1$^-$) is discussed, and absolute cross sections
predicted.
| arxiv topic:nucl-th |
arxiv_dataset-112221905.03764 | Higgs Boson Studies at Future Particle Colliders
hep-ph hep-ex
This document aims to provide an assessment of the potential of future
colliding beam facilities to perform Higgs boson studies. The analysis builds
on the submissions made by the proponents of future colliders to the European
Strategy Update process, and takes as its point of departure the results
expected at the completion of the HL-LHC program. This report presents
quantitative results on many aspects of Higgs physics for future collider
projects of sufficient maturity using uniform methodologies.
| arxiv topic:hep-ph hep-ex |
arxiv_dataset-112231905.03864 | Adversarially Trained Autoencoders for Parallel-Data-Free Voice
Conversion
eess.AS cs.LG cs.SD
We present a method for converting the voices between a set of speakers. Our
method is based on training multiple autoencoder paths, where there is a single
speaker-independent encoder and multiple speaker-dependent decoders. The
autoencoders are trained with an addition of an adversarial loss which is
provided by an auxiliary classifier in order to guide the output of the encoder
to be speaker independent. The training of the model is unsupervised in the
sense that it does not require collecting the same utterances from the speakers
nor does it require time aligning over phonemes. Due to the use of a single
encoder, our method can generalize to converting the voice of out-of-training
speakers to speakers in the training dataset. We present subjective tests
corroborating the performance of our method.
| arxiv topic:eess.AS cs.LG cs.SD |
arxiv_dataset-112241905.03964 | An extension of BCOV invariant
math.DG
Bershadsky, Cecotti, Ooguri and Vafa constructed a real valued invariant for
Calabi-Yau manifolds, which is called the BCOV invariant. In this paper, we
consider a pair $(X,Y)$, where $X$ is a compact Kaehler manifold and
$Y\in\big|K_X^m\big|$ with $m\in\mathbb{Z}\backslash\{0,-1\}$. We extend the
BCOV invariant to such pairs. If $m=-2$ and $X$ is a rigid del Pezzo surface,
the extended BCOV invariant is equivalent to Yoshikawa's equivariant BCOV
invariant. If $m=1$, the extended BCOV invariant is well-behaved under blow-up.
It was conjectured that birational Calabi-Yau threefolds have the same BCOV
invariant. As an application of our extended BCOV invariant, we show that this
conjecture holds for Atiyah flops.
| arxiv topic:math.DG |
arxiv_dataset-112251905.04064 | P4BFT: Hardware-Accelerated Byzantine-Resilient Network Control Plane
cs.NI cs.DC
Byzantine Fault Tolerance (BFT) enables correct operation of distributed,
i.e., replicated applications in the face of malicious take-over and
faulty/buggy individual instances. Recently, BFT designs have gained traction
in the context of Software Defined Networking (SDN). In SDN, controller
replicas are distributed and their state replicated for high availability
purposes. Malicious controller replicas, however, may destabilize the control
plane and manipulate the data plane, thus motivating the BFT requirement.
Nonetheless, deploying BFT in practice comes at a disadvantage of increased
traffic load stemming from replicated controllers, as well as a requirement for
proprietary switch functionalities, thus putting strain on switches' control
plane where particular BFT actions must be executed in software.
P4BFT leverages an optimal strategy to decrease the total amount of messages
transmitted to switches that are the configuration targets of SDN controllers.
It does so by means of message comparison and deduction of correct messages in
the determined optimal locations in the data plane. In terms of the incurred
control plane load, our P4-based data plane extensions outperform the existing
solutions by ~33.2% and ~40.2% on average, in random 128-switch and
Fat-Tree/Internet2 topologies, respectively. To validate the correctness and
performance gains of P4BFT, we deploy bmv2 and Netronome Agilio SmartNIC-based
topologies. The advantages of P4BFT can thus be reproduced both with software
switches and "commodity" P4-enabled hardware. A hardware-accelerated controller
packet comparison procedure results in an average 96.4% decrease in processing
delay per request compared to existing software approaches.
| arxiv topic:cs.NI cs.DC |
arxiv_dataset-112261905.04164 | Recycling the resource: Sequential usage of shared state in quantum
teleportation with weak measurements
quant-ph
Complete measurements, while providing maximal information gain, results in
destruction of the shared entanglement. In the standard teleportation scheme,
the sender's measurement on the shared entangled state between the sender and
the receiver has that consequence. We propose here a teleportation scheme
involving weak measurements which can sustain entanglement upto a certain level
so that the reusability of the shared resource state is possible. The
measurements are chosen in such a way that it is weak enough to retain
entanglement and hence can be reused for quantum tasks, yet adequately strong
to ensure quantum advantage in the protocol. In this scenario, we report that
at most six sender-receiver duos can reuse the state, when the initial shared
state is entangled in a finite neighborhood of the maximally entangled state
and for a suitable choice of weak measurements. However, we observe that the
reusability number decreases with the decrease in the entanglement of the
initial shared state. Among the weakening strategies studied, Bell measurement
admixed with white noise performs better than any other low-rank weak
measurements in this situation.
| arxiv topic:quant-ph |
arxiv_dataset-112271905.04264 | PartitionedVC: Partitioned External Memory Graph Analytics Framework for
SSDs
cs.DC
Graph analytics are at the heart of a broad range of applications such as
drug discovery, page ranking, and recommendation systems. When graph size
exceeds memory size, out-of-core graph processing is needed. For the widely
used external memory graph processing systems, accessing storage becomes the
bottleneck. We make the observation that nearly all graph algorithms have a
dynamically varying number of active vertices that must be processed in each
iteration. However, existing graph processing frameworks, such as GraphChi,
load the entire graph in each iteration even if a small fraction of the graph
is active. This limitation is due to the structure of the data storage used by
these systems. In this work, we propose to use a compressed sparse row (CSR)
based graph storage that is more amenable for selectively loading only a few
active vertices in each iteration. But CSR based systems suffers from random
update propagation to many target vertices. To solve this challenge, we propose
to use a multi-log update mechanism that logs updates separately, rather than
directly update the active edges in a graph. Our proposed multi-log system
maintains a separate log per each vertex interval. This separation enables us
to efficiently process each vertex interval by just loading the corresponding
log. Further, while accessing SSD pages with fewer active vertex data, we
reduce the read amplification due to the page granular accesses in SSD by
logging the active vertex data in the current iteration and efficiently reading
the log in the next iteration. Over the current state of the art out-of-core
graph processing framework, our PartitionedVC improves performance by up to
$17.84\times$, $1.19\times$, $1.65\times$, $1.38\times$, $3.15\times$, and
$6.00\times$ for the widely used bfs, pagerank, community detection, graph
coloring, maximal independent set, and random-walk applications, respectively.
| arxiv topic:cs.DC |
arxiv_dataset-112281905.04364 | Ax-Schanuel for $GL_n$
math.NT math.AG
In this paper we prove an Ax-Schanuel type result for the exponential
functions for general linear groups over $\mathbb{C}$. We prove the result
first for the group of upper triangular matrices and then for the group $GL_n$
of all $n\times n$ invertible matrices over $\mathbb{C}$. We also obtain
Ax-Lindemann type results for these maps as a corollary, characterizing the
bi-algebraic subsets of these maps.
| arxiv topic:math.NT math.AG |
arxiv_dataset-112291905.04464 | Wind-sustained viscous solitons
physics.flu-dyn
When wind blows at the surface of a liquid of sufficiently high viscosity, a
wave packet of small amplitude is first generated, which sporadically forms
large-amplitude fluid bumps that rapidly propagate downstream. These nonlinear
structures, first observed by Francis [Philos. Mag. 42, 695 (1954)], have an
almost vertical rear facing the wind and a weak slope at the front. We call
them viscous solitons. We investigate their dynamics in a wind-tunnel
experiment using silicon oil of kinematic viscosity 1000 mm^2 s^-1 by means of
laser sheet profilometry and particle image velocimetry. We give evidence of
their subcritical nature: they are emitted in a region of large shear stress
but, once formed, they are sustained by the wind and propagate in a region of
lower stress. Their propagation velocity is given by the balance between
aerodynamic drag in the air and viscous drag in the liquid. The stable soliton
branch of the subcritical bifurcation diagram is reconstructed from the
measured soliton amplitude at various wind velocities and distances along the
channel. At large wind velocity, the emission frequency of solitons increases,
resulting in a long-range sheltering of downstream mature solitons by newly
formed upstream solitons, which limits their course.
| arxiv topic:physics.flu-dyn |
arxiv_dataset-112301905.04564 | PrivateJobMatch: A Privacy-Oriented Deferred Multi-Match Recommender
System for Stable Employment
cs.DS cs.IR cs.LG
Coordination failure reduces match quality among employers and candidates in
the job market, resulting in a large number of unfilled positions and/or
unstable, short-term employment. Centralized job search engines provide a
platform that connects directly employers with job-seekers. However, they
require users to disclose a significant amount of personal data, i.e., build a
user profile, in order to provide meaningful recommendations. In this paper, we
present PrivateJobMatch -- a privacy-oriented deferred multi-match recommender
system -- which generates stable pairings while requiring users to provide only
a partial ranking of their preferences. PrivateJobMatch explores a series of
adaptations of the game-theoretic Gale-Shapley deferred-acceptance algorithm
which combine the flexibility of decentralized markets with the intelligence of
centralized matching. We identify the shortcomings of the original algorithm
when applied to a job market and propose novel solutions that rely on machine
learning techniques. Experimental results on real and synthetic data confirm
the benefits of the proposed algorithms across several quality measures. Over
the past year, we have implemented a PrivateJobMatch prototype and deployed it
in an active job market economy. Using the gathered real-user preference data,
we find that the match-recommendations are superior to a typical decentralized
job market---while requiring only a partial ranking of the user preferences.
| arxiv topic:cs.DS cs.IR cs.LG |
arxiv_dataset-112311905.04664 | Using Oshima splines to produce accurate numerical results and high
quality graphical output
math.NA
We illustrate the use of Oshima splines in producing high-quality \LaTeX\
output in two cases: first, the numerical computation of derivatives and
integrals, and second, the display of silhouettes and wireframe surfaces, using
the macros package KeTCindy. Both cases are of particular interest for college
and university teachers wanting to create handouts to be used by students, or
drawing figures for a research paper. When dealing with numerical computations,
KeTCindy can make a call to the CAS Maxima to check for accuracy; in the case
of surface graphics, it is particularly important to be able to detect
intersections of projected curves, and we show how to do it in a seamlessly
manner using Oshima splines in KeTCindy. A C compiler can be called in this
case to speed up computations.
| arxiv topic:math.NA |
arxiv_dataset-112321905.04764 | Conformal Teleparallel Theories and Weyl Geometry
gr-qc hep-th math-ph math.MP
Despite the fact that General Relativity (GR) has been very successful, many
alternative theories of gravity have attracted the attention of a significant
number of theoretical physicists. Among these theories, we have theories with
conformal symmetry. Here, the use of Weyl geometry to deal with conformal
teleparallel gravity is reviewed in great detail. As an application, a model
that can be set to be equivalent to the Teleparallel Equivalent of General
Relativity (TEGR) and is invariant under diffeomorphisms, local Lorentz
transformations (LLT) and Weyl transformations (WT) is created. Some $pp$-wave,
spherically symmetric and cosmological solutions are obtained. It turns out
that the class of possibles solutions is wider than that of TEGR. In addition,
the total and the gravitational energies of the universe are calculated and
analyzed.
| arxiv topic:gr-qc hep-th math-ph math.MP |
arxiv_dataset-112331905.04864 | Nonvolatile Memory Cell Based on Memristor Emulator
cs.ET
Memristor, one of the fundamental circuit elements, has promising
applications in non-volatile memory and storage technology as it can
theoretically achieve infinite states. Information can be stored independently
in these states and retrieved whenever required. In this paper, we have
proposed a non volatile memory cell based on memristor emulator. The circuit is
able to perform read and write operations. In this memristor based memroy cell,
unipolar pulse is used for writing and bipolar pulse is used for reading.
Unlike other earlier designs, the circuit does not need external read/write
enable switches to switch between read and write operations; the switching is
achieved by the zero average bipolar read pulse given after the completion of
write cycle. In our proposed memristor based memory cell, single bit can be
read and any voltages from 0 to 5 volts can be written. Mathematical analysis
and the simulation results of memristor emulator based read write circuit have
been presented to confirm its operation.
| arxiv topic:cs.ET |
arxiv_dataset-112341905.04964 | Exogenous Rewards for Promoting Cooperation in Scale-Free Networks
cs.GT cs.MA cs.SI econ.TH physics.soc-ph
The design of mechanisms that encourage pro-social behaviours in populations
of self-regarding agents is recognised as a major theoretical challenge within
several areas of social, life and engineering sciences. When interference from
external parties is considered, several heuristics have been identified as
capable of engineering a desired collective behaviour at a minimal cost.
However, these studies neglect the diverse nature of contexts and social
structures that characterise real-world populations. Here we analyse the impact
of diversity by means of scale-free interaction networks with high and low
levels of clustering, and test various interference mechanisms using
simulations of agents facing a cooperative dilemma. Our results show that
interference on scale-free networks is not trivial and that distinct levels of
clustering react differently to each interference mechanism. As such, we argue
that no tailored response fits all scale-free networks and present which
mechanisms are more efficient at fostering cooperation in both types of
networks. Finally, we discuss the pitfalls of considering reckless interference
mechanisms.
| arxiv topic:cs.GT cs.MA cs.SI econ.TH physics.soc-ph |
arxiv_dataset-112351905.05064 | Physical Layer Security for NOMA: Requirements, Merits, Challenges, and
Recommendations
eess.SP
Non-Orthogonal Multiple Access (NOMA) has been recognized as one of the most
significant enabling technologies for future wireless systems due to its
eminent spectral efficiency, ability to provide an additional degree of freedom
for Ultra Reliable Low Latency Communications (URLLC) and grant free random
access. Meanwhile, Physical Layer Security (PLS) has got much attention for
future wireless communication systems due to its capability to provide security
without relying on traditional cryptography based algorithms. In this article,
security design requirements for NOMA and solutions provided by PLS to fulfill
these requirements are discussed. The merits and challenges arising from
employing PLS to NOMA are identified. Finally, future recommendations and
prospective solutions are also presented.
| arxiv topic:eess.SP |
arxiv_dataset-112361905.05164 | Local limit theorem in deterministic systems
math.DS math.PR
We show that for every ergodic and aperiodic probability preserving system,
there exists a $\mathbb{Z}$ valued, square integrable function $f$ such that
the partial sums process of the time series $\left\{f\circ
T^i\right\}_{i=0}^\infty$ satisfies the lattice local limit theorem.
| arxiv topic:math.DS math.PR |
arxiv_dataset-112371905.05264 | Programming multi-level quantum gates in disordered computing reservoirs
via machine learning and TensorFlow
quant-ph cs.LG physics.optics
Novel machine learning computational tools open new perspectives for quantum
information systems. Here we adopt the open-source programming library
TensorFlow to design multi-level quantum gates including a computing reservoir
represented by a random unitary matrix. In optics, the reservoir is a
disordered medium or a multi-modal fiber. We show that trainable operators at
the input and the readout enable one to realize multi-level gates. We study
various qudit gates, including the scaling properties of the algorithms with
the size of the reservoir. Despite an initial low slop learning stage,
TensorFlow turns out to be an extremely versatile resource for designing gates
with complex media, including different models that use spatial light
modulators with quantized modulation levels.
| arxiv topic:quant-ph cs.LG physics.optics |
arxiv_dataset-112381905.05364 | Direct evidence for charge compensation induced large magnetoresistance
in thin WTe2
cond-mat.mes-hall
Since the discovery of extremely large non-saturating magnetoresistance (MR)
in WTe2, much effort has been devoted to understanding the underlying
mechanism, which is still under debate. Here, we explicitly identify the
dominant physical origin of the large non-saturating MR through in-situ tuning
of the magneto-transport properties in thin WTe2 film. With an electrostatic
doping approach, we observed a non-monotonic gate dependence of the MR. The MR
reaches a maximum (10600%) in thin WTe2 film at certain gate voltage where
electron and hole concentrations are balanced, indicating that the charge
compensation is the dominant mechanism of the observed large MR. Besides, we
show that the temperature dependent magnetoresistance exhibits similar tendency
with the carrier mobility when the charge compensation is retained, revealing
that distinct scattering mechanisms may be at play for the temperature
dependence of magneto-transport properties. Our work would be helpful for
understanding mechanism of the large MR in other nonmagnetic materials and
offers an avenue for achieving large MR in the non-magnetic materials with
electron-hole pockets.
| arxiv topic:cond-mat.mes-hall |
arxiv_dataset-112391905.05464 | Sensitivity to neutrino-antineutrino transitions for boron neutrinos
hep-ph
Neutrino-antineutrino conversion is an important new physics process. The
observation of this phenomenon could indicate total lepton number violation and
potential CPT-violation. Searching for the appearance of electron antineutrinos
from solar neutrinos from $\rm^8B$ decay allows us to hunt for this rare
process, although it can also be explained by other mechanisms or hypotheses.
This analysis examines the capabilities of observing neutrino-antineutrino
transition from $\rm^8B$ unoscillated solar neutrinos using different liquid
scintillator detector configurations. High energy reactor neutrinos and
atmospheric neutrinos are the two dominant background sources. Large volume
liquid scintillator detectors with deep underground shielding, placed far away
from reactors and with capabilities of pulse shaped discrimination will
significantly increase the search sensitivity. It is demonstrated that for the
next generation of large liquid scintillator detectors being planned or under
construction, the sensitivity to the average probability of
neutrino-antineutrino transitions can reach $10^{-6}$, which is an order of
magnitude better than the current best experimental limits.
| arxiv topic:hep-ph |
arxiv_dataset-112401905.05564 | Luminosity and Physics Considerations on HL-LHC and HE-LHC based mu-p
Colliders
physics.acc-ph hep-ex hep-ph
Construction of future Muon Collider tangential to the Large Hadron Collider
will give opportunity to realize mu-p collisions at multi-TeV center of mass
energies. Using nominal parameters of high luminosity and high energy upgrades
of the LHC, as well as design parameters of muon colliders, it is shown that
L_mu-p of order of 10^33 cm^-2s^-1 is achievable for different options with
sqrt(s)_mu-p from 4.58 TeV to 12.7 TeV. Certainly, proposed mu-p colliders have
a huge potential for clarifying QCD basics and searches for new physics.
| arxiv topic:physics.acc-ph hep-ex hep-ph |
arxiv_dataset-112411905.05664 | On a Poincar\'e polynomial from Khovanov homology and Vassiliev
invariants
math.GT hep-th math-ph math.MP math.QA
We introduce a Poincar\'{e} polynomial with two-variable $t$ and $x$ for
knots, derived from Khovanov homology, where the specialization $(t, x)$ $=$
$(1, -1)$ is a Vassiliev invariant of order $n$. Since for every $n$, there
exist non-trivial knots with the same value of the Vassiliev invariant of order
$n$ as that of the unknot, there has been no explicit formulation of a
perturbative knot invariant which is a coefficient of $y^n$ by the replacement
$q=e^y$ for the quantum parameter $q$ of a quantum knot invariant, and which
distinguishes the above knots together with the unknot. The first formulation
is our polynomial.
| arxiv topic:math.GT hep-th math-ph math.MP math.QA |
arxiv_dataset-112421905.05764 | An Inflationary Probe of Cosmic Higgs Switching
hep-th astro-ph.CO hep-ph
A scalar Higgs field can be repeatedly switched on and off when it couples to
a classically oscillating scalar modulus field. The modulus flips the Higgs
mass term between stable and tachyonic values. We study a cosmological scenario
in which such repeated phase transitions occur during inflation. An irrelevant
operator coupling the Higgs field to the inflaton can then imprint the pattern
of phase transitions in the correlation functions of the inflaton. Using both
numerical and analytic studies, we show that the inflaton 2-point function
carries characteristic imprints of the modulus oscillation and its effect on
the Higgs boson. We briefly remark on the potential observability of such
patterns and how they might be distinguished from other dynamics in the early
universe.
| arxiv topic:hep-th astro-ph.CO hep-ph |
arxiv_dataset-112431905.05864 | Constraints and Horizons for de Sitter with Extra Dimensions
hep-th gr-qc
In order for spacetimes with static extra dimensions to have 4-dimensional de
Sitter expansion they must have at least positive curvature, warping sourced by
the 4-d expansion, or violate the null energy condition everywhere in the extra
dimensions. We show how this constraint arises from the null Raychaudhuri
equation, and that it is independent of the matter content, the Einstein
equations, and is true point-by-point in the extra dimensions (not integrated),
setting it apart from other no-go theorems in the literature. We present two
previously known examples -- a Freund-Rubin compactification with bulk
cosmological constant, and a Randall-Sundrum model where the mismatch between
the brane and bulk cosmological constants sources non-trivial warping -- which
evade the constraint, and discuss the implications for flux compactifications.
We also show that any spacetime with static compact extra dimensions and
4-dimensional de Sitter expansion has an apparent horizon and antitrapped
region in the extra dimensions, which may have interesting implications for the
dynamics of bulk fields in cosmology.
| arxiv topic:hep-th gr-qc |
arxiv_dataset-112441905.05964 | Deep Kinship Verification via Appearance-shape Joint Prediction and
Adaptation-based Approach
cs.CV
Kinship verification aims to identify the kin relation between two given face
images. It is a very challenging problem due to the lack of training data and
facial similarity variations between kinship pairs. In this work, we build a
novel appearance and shape based deep learning pipeline. First we adopt the
knowledge learned from general face recognition network to learn general facial
features. Afterwards, we learn kinship oriented appearance and shape features
from kinship pairs and combine them for the final prediction. We have evaluated
the model performance on a widely used popular benchmark and demonstrated the
superiority over the state-of-the-art.
| arxiv topic:cs.CV |
arxiv_dataset-112451905.06064 | On O'hara knot energies I: Regularity for critical knots
math.AP math.AT math.DG math.GT
We develop a regularity theory for extremal knots of scale invariant knot
energies defined by J. O'hara in 1991. This class contains as a special case
the M\"obius energy.
For the M\"obius energy, due to the celebrated work of Freedman, He, and
Wang, we have a relatively good understanding. Their approch is crucially based
on the invariance of the M\"obius energy under M\"obius transforms, which fails
for all the other O'hara energies.
We overcome this difficulty by re-interpreting the scale invariant O'hara
knot energies as a nonlinear, nonlocal $L^p$-energy acting on the unit tangent
of the knot parametrization. This allows us to draw a connection to the theory
of (fractional) harmonic maps into spheres. Using this connection we are able
to adapt the regularity theory for degenerate fractional harmonic maps in the
critical dimension to prove regularity for minimizers and critical knots of the
scale-invariant O'hara knot energies.
| arxiv topic:math.AP math.AT math.DG math.GT |
arxiv_dataset-112461905.06164 | Higher order corrections to the mean-field description of the dynamics
of interacting bosons
math-ph math.MP
In this paper, we introduce a novel method for deriving higher order
corrections to the mean-field description of the dynamics of interacting
bosons. More precisely, we consider the dynamics of $N$ $d$-dimensional bosons
for large $N$. The bosons initially form a Bose-Einstein condensate and
interact with each other via a pair potential of the form
$(N-1)^{-1}N^{d\beta}v(N^\beta\cdot)$ for $\beta\in[0,\frac{1}{4d})$. We derive
a sequence of $N$-body functions which approximate the true many-body dynamics
in $L^2(\mathbb{R}^{d N})$-norm to arbitrary precision in powers of $N^{-1}$.
The approximating functions are constructed as Duhamel expansions of finite
order in terms of the first quantised analogue of a Bogoliubov time evolution.
| arxiv topic:math-ph math.MP |
arxiv_dataset-112471905.06264 | Majorana Fermion Quantum Mechanics for Higher Rank Tensors
hep-th cond-mat.str-el
We study quantum mechanical models in which the dynamical degrees of freedom
are real fermionic tensors of rank five and higher. They are the non-random
counterparts of the Sachdev-Ye-Kitaev (SYK) models where the Hamiltonian
couples six or more fermions. For the tensors of rank five, there is a unique
$O(N)^5$ symmetric sixth-order Hamiltonian leading to a solvable large $N$
limit dominated by the melonic diagrams. We solve for the complete energy
spectrum of this model when $N=2$ and deduce exact expressions for all the
eigenvalues. The subset of states which are gauge invariant exhibit
degeneracies related to the discrete symmetries of the gauged model. We also
study quantum chaos properties of the tensor model and compare them with those
of the $q=6$ SYK model. For $q>6$ there is a rapidly growing number of
$O(N)^{q-1}$ invariant tensor interactions. We focus on those of them that are
maximally single-trace - their stranded diagrams stay connected when any set of
$q-3$ colors is erased. We present a general discussion of why the tensor
models with maximally single-trace interactions have large $N$ limits dominated
by the melonic diagrams. We solve the large $N$ Schwinger-Dyson equations for
the higher rank Majorana tensor models and show that they match those of the
corresponding SYK models exactly. We also study other gauge invariant operators
present in the tensor models.
| arxiv topic:hep-th cond-mat.str-el |
arxiv_dataset-112481905.06364 | Dynamic model of firms competitive interaction on the market with
taxation
q-fin.GN math.OC
In this article three models of firms interaction on the market are
described. One of these models is described by using a differential equation
and by Lotka-Volterra model, where the equation has a different form. Also,
there are models of non-competing and competing firms. The article presents an
algorithm for solving the interaction of competing firms in taxation and the
calculation of a compromise point. Besides, the article presents a compromise
between the interests of a state and an enterprise.
| arxiv topic:q-fin.GN math.OC |
arxiv_dataset-112491905.06464 | Streetscape augmentation using generative adversarial networks: insights
related to health and wellbeing
cs.CY cs.CV cs.LG stat.ML
Deep learning using neural networks has provided advances in image style
transfer, merging the content of one image (e.g., a photo) with the style of
another (e.g., a painting). Our research shows this concept can be extended to
analyse the design of streetscapes in relation to health and wellbeing
outcomes. An Australian population health survey (n=34,000) was used to
identify the spatial distribution of health and wellbeing outcomes, including
general health and social capital. For each outcome, the most and least
desirable locations formed two domains. Streetscape design was sampled using
around 80,000 Google Street View images per domain. Generative adversarial
networks translated these images from one domain to the other, preserving the
main structure of the input image, but transforming the `style' from locations
where self-reported health was bad to locations where it was good. These
translations indicate that areas in Melbourne with good general health are
characterised by sufficient green space and compactness of the urban
environment, whilst streetscape imagery related to high social capital
contained more and wider footpaths, fewer fences and more grass. Beyond
identifying relationships, the method is a first step towards
computer-generated design interventions that have the potential to improve
population health and wellbeing.
| arxiv topic:cs.CY cs.CV cs.LG stat.ML |
arxiv_dataset-112501905.06564 | Playing with ghosts in a Dynkin game
math.PR econ.GN math.OC q-fin.EC
We study a class of optimal stopping games (Dynkin games) of preemption type,
with uncertainty about the existence of competitors. The set-up is well-suited
to model, for example, real options in the context of investors who do not want
to publicly reveal their interest in a certain business opportunity. We show
that there exists a Nash equilibrium in randomized stopping times which is
described explicitly in terms of the corresponding one-player game.
| arxiv topic:math.PR econ.GN math.OC q-fin.EC |
arxiv_dataset-112511905.06664 | Energy deposition on nuclear emulsion by slow recoil ions for
directional dark matter searches
physics.ins-det hep-ex
The electronic energy deposited on nuclear emulsions due to C ions of 5 --
200~keV and Kr ions of 5 -- 600~keV are evaluated and compared with those due
to fast ions for design and construction of fine grain nuclear emulsion for
directional dark matter searches. Nuclear quenching factors and the electronic
LET (linear energy transfer), the specific electronic energy deposited along
the ion track, are evaluated. The so-called core and penumbra of heavy-ion
track structure is modified for understanding the track due to recoil ions
produced by dark matter candidate, WIMPs, striking nucleus in the AgBr crystal
of nuclear emulsion. The very heavy recoil ions, 100 -- 180~keV Pb ions,
produced in $\alpha$-decay are also studied. In addition, the track structures
due to proton ions of 25 -- 80~keV are evaluated to consider the influence of
background neutrons in underground laboratories.
| arxiv topic:physics.ins-det hep-ex |
arxiv_dataset-112521905.06764 | Learning Visually Consistent Label Embeddings for Zero-Shot Learning
cs.CV
In this work, we propose a zero-shot learning method to effectively model
knowledge transfer between classes via jointly learning visually consistent
word vectors and label embedding model in an end-to-end manner. The main idea
is to project the vector space word vectors of attributes and classes into the
visual space such that word representations of semantically related classes
become more closer, and use the projected vectors in the proposed embedding
model to identify unseen classes. We evaluate the proposed approach on two
benchmark datasets and the experimental results show that our method yields
significant improvements in recognition accuracy.
| arxiv topic:cs.CV |
arxiv_dataset-112531905.06864 | Consistency of CMB experiments beyond cosmic variance
astro-ph.CO
The next generation of Cosmic Microwave Background experiments will produce
cosmic variance limited observations over a large fraction of sky and for a
large range of multipoles. In this work we discuss different consistency tests
that can be performed with the upcoming data from the Simons Observatory and
the Planck data. We quantify the level of expected cosmological parameter
shifts probed by these tests. We discuss the effect of difference in frequency
of observation and present forecasts on a direct measurement of the Planck
T-to-E leakage beam. We find that instrumental systematics in either of the
experiments will be assessed with an exquisite precision, well beyond the
intrinsic uncertainties due to the CMB cosmic variance.
| arxiv topic:astro-ph.CO |
arxiv_dataset-112541905.06964 | Broad-band X-ray analysis of local mid-infrared selected Compton-thick
AGN candidates
astro-ph.GA astro-ph.HE
The estimate of the number and space density of obscured AGN over cosmic time
still represents an open issue. While the obscured AGN population is a key
ingredient of the X-ray background synthesis models and is needed to reproduce
its shape, a complete census of obscured AGN is still missing. Here we test the
selection of obscured sources among the local 12-micron sample of Seyfert
galaxies. Our selection is based on a difference up to three orders of
magnitude in the ratio between the AGN bolometric luminosity, derived from the
spectral energy distribution (SED) decomposition, and the same quantity
obtained by the published XMM-Newton 2-10 keV luminosity.
The selected sources are UGC05101, NGC1194 and NGC3079 for which the
available X-ray wide bandpass, from Chandra and XMM-Newton plus NuSTAR data,
extending to energies up to ~30-45 keV, allows us an accurate determination of
the column density, and hence of the true intrinsic power.
The newly derived NH values clearly indicate heavy obscuration (about 1.2,
2.1 and 2.4 x10^{24} cm-2 for UGC05101, NGC1194 and NGC3079, respectively) and
are consistent with the prominent silicate absorption feature observed in the
Spitzer-IRS spectra of these sources (at 9.7 micron rest frame). We finally
checked that the resulting X-ray luminosities in the 2-10 keV band are in good
agreement with those derived from the mid-IR band through empirical L_MIR-L_X
relations.
| arxiv topic:astro-ph.GA astro-ph.HE |
arxiv_dataset-112551905.07064 | The Need for Laboratory Measurements and Ab Initio Studies to Aid
Understanding of Exoplanetary Atmospheres
astro-ph.EP
We are now on a clear trajectory for improvements in exoplanet observations
that will revolutionize our ability to characterize their atmospheric
structure, composition, and circulation, from gas giants to rocky planets.
However, exoplanet atmospheric models capable of interpreting the upcoming
observations are often limited by insufficiencies in the laboratory and
theoretical data that serve as critical inputs to atmospheric physical and
chemical tools. Here we provide an up-to-date and condensed description of
areas where laboratory and/or ab initio investigations could fill critical gaps
in our ability to model exoplanet atmospheric opacities, clouds, and chemistry,
building off a larger 2016 white paper, and endorsed by the NAS Exoplanet
Science Strategy report. Now is the ideal time for progress in these areas, but
this progress requires better access to, understanding of, and training in the
production of spectroscopic data as well as a better insight into chemical
reaction kinetics both thermal and radiation-induced at a broad range of
temperatures. Given that most published efforts have emphasized relatively
Earth-like conditions, we can expect significant and enlightening discoveries
as emphasis moves to the exotic atmospheres of exoplanets.
| arxiv topic:astro-ph.EP |
arxiv_dataset-112561905.07164 | Extended Magnetic Dome Induced by Low Pressures in Superconducting
FeSe$_\mathrm{1\text{-}x}$S$_\mathrm{x}$
cond-mat.supr-con cond-mat.str-el
We report muon spin rotation ($\mu$SR) and magnetization measurements under
pressure on Fe$_{1+\delta}$Se$_\mathrm{1\text{-}x}$S$_\mathrm{x}$ with x
$\approx 0.11$.Above $p\approx0.6$ GPa we find microscopic coexistence of
superconductivity with an extended dome of long range magnetic order that spans
a pressure range between previously reported separated magnetic phases. The
magnetism initially competes on an atomic scale with the coexisting
superconductivity leading to a local maximum and minimum of the superconducting
$T_\mathrm{c}(p)$. The maximum of $T_\mathrm{c}$ corresponds to the onset of
magnetism while the minimum coincides with the pressure of strongest
competition. A shift of the maximum of $T_\mathrm{c}(p)$ for a series of single
crystals with x up to 0.14 roughly extrapolates to a putative magnetic and
superconducting state at ambient pressure for x $\geq0.2$.
| arxiv topic:cond-mat.supr-con cond-mat.str-el |
arxiv_dataset-112571905.07264 | Collaborative Interactive Learning -- A clarification of terms and a
differentiation from other research fields
cs.LG cs.AI
The field of collaborative interactive learning (CIL) aims at developing and
investigating the technological foundations for a new generation of smart
systems that support humans in their everyday life. While the concept of CIL
has already been carved out in detail (including the fields of dedicated CIL
and opportunistic CIL) and many research objectives have been stated, there is
still the need to clarify some terms such as information, knowledge, and
experience in the context of CIL and to differentiate CIL from recent and
ongoing research in related fields such as active learning, collaborative
learning, and others. Both aspects are addressed in this paper.
| arxiv topic:cs.LG cs.AI |
arxiv_dataset-112581905.07364 | Gapped Continuum Kaluza-Klein spectrum
hep-ph hep-th
We consider a warped five-dimensional model with an ultraviolet (UV) brane
and, on top of the Standard Model isolated modes, continua of KK modes with
different mass gaps for all particles: gauge bosons, fermions, graviton, radion
and Higgs boson. The model can be considered as a modelization in five
dimensions of gapped unparticles. The five dimensional metric has a
singularity, at a finite (infinite) value of the proper (conformal) coordinate,
which is admissible as it supports finite temperature in the form of a black
hole horizon. An infrared (IR) brane, with particular jumping conditions, is
introduced to trigger correct electroweak breaking. The gravitational metric is
AdS$_5$ near the UV brane, to solve the hierarchy problem with a fundamental
Planck scale, and linear, in conformal coordinates, near the IR, as in the
linear dilaton and five-dimensional clockwork models. The branes, and
singularity, distances are fixed, \`a la Goldberger-Wise, by a bulk scalar
field with brane potentials explicitly breaking the conformal symmetry. The
bosonic continuum of KK modes with the smallest mass gap are those of gauge
bosons, and so they are the most likely produced at the LHC. Mass gaps of the
continuum of KK fermions do depend on their localization in the extra
dimension. We have computed the spectral functions, and arbitrary Green's
functions, and shown how they can modify some Standard Model processes.
| arxiv topic:hep-ph hep-th |
arxiv_dataset-112591905.07464 | A Multi-Task Learning Framework for Extracting Drugs and Their
Interactions from Drug Labels
cs.CL
Preventable adverse drug reactions as a result of medical errors present a
growing concern in modern medicine. As drug-drug interactions (DDIs) may cause
adverse reactions, being able to extracting DDIs from drug labels into
machine-readable form is an important effort in effectively deploying drug
safety information. The DDI track of TAC 2018 introduces two large
hand-annotated test sets for the task of extracting DDIs from structured
product labels with linkage to standard terminologies. Herein, we describe our
approach to tackling tasks one and two of the DDI track, which corresponds to
named entity recognition (NER) and sentence-level relation extraction
respectively. Namely, our approach resembles a multi-task learning framework
designed to jointly model various sub-tasks including NER and interaction type
and outcome prediction. On NER, our system ranked second (among eight teams) at
33.00% and 38.25% F1 on Test Sets 1 and 2 respectively. On relation extraction,
our system ranked second (among four teams) at 21.59% and 23.55% on Test Sets 1
and 2 respectively.
| arxiv topic:cs.CL |
arxiv_dataset-112601905.07564 | Rates of convergence in the CLT for nonlinear statistics under relaxed
moment conditions
math.PR
This paper is concerned with normal approximation under relaxed moment
conditions using Stein's method. We obtain the explicit rates of convergence in
the central limit theorem for (i) nonlinear statistics with finite absolute
moment of order $2+\delta\in(2,3];$ (ii) nonlinear statistics with vanishing
third moment and finite absolute moment of order $3+\delta\in(3,4].$ When
applied to specific examples, these rates are of the optimal order
$O(n^{-\frac{\delta}{2}})$ and $O(n^{-\frac{1+\delta}{2}}).$ Our proof are
based on the covariance identify formula and simple observations about the
solution of Stein's equation.
| arxiv topic:math.PR |
arxiv_dataset-112611905.07664 | The uniform perfectness of diffeomorphism groups of open manifolds
math.GT math.DG math.DS math.GR
In this paper we study the uniform perfectness, boundedness and uniform
simplicity of diffeomorphism groups of compact manifolds with boundary and open
manifolds and obtain some upper bounds of their diameters with respect to
commutator length, those with support in balls and conjugation-generated norm.
| arxiv topic:math.GT math.DG math.DS math.GR |
arxiv_dataset-112621905.07764 | Study designs for extending causal inferences from a randomized trial to
a target population
stat.ME stat.AP
We examine study designs for extending (generalizing or transporting) causal
inferences from a randomized trial to a target population. Specifically, we
consider nested trial designs, where randomized individuals are nested within a
sample from the target population, and non-nested trial designs, including
composite dataset designs, where a randomized trial is combined with a
separately obtained sample of non-randomized individuals from the target
population. We show that the causal quantities that can be identified in each
study design depend on what is known about the probability of sampling
non-randomized individuals. For each study design, we examine identification of
potential outcome means via the g-formula and inverse probability weighting.
Last, we explore the implications of the sampling properties underlying the
designs for the identification and estimation of the probability of trial
participation.
| arxiv topic:stat.ME stat.AP |
arxiv_dataset-112631905.07864 | Deep Inelastic Scattering on an Extremal RN-AdS Black Hole II:
Holographic Fermi Surface
hep-th hep-ph nucl-th
We consider deep inelastic scattering (DIS) on a dense nucleus described as
an extremal RN-AdS black hole with holographic quantum fermions in the bulk. We
evaluate the 1-loop fermion contribution to the R-current on the charged black
hole, and map it on scattering off a Fermi surface of a dense and large nucleus
with fixed atomic number. Near the black hole horizon, the geometry is that of
AdS$_2\times $R$^3$ where the fermions develop an emergent Fermi surface with
anomalous dimensions. DIS scattering off these fermions yields to anomalous
partonic distributions mostly at large-x, as well as modified hard scattering
rules. The pertinent R-ratio for the black hole is discussed. For comparison,
the structure functions and the R-ratio in the probe or dilute limit with no
back-reaction on the geometry, are also derived. We formulate a hybrid
holographic model for DIS scattering on heavy and light nuclei, which compares
favorably to the existing data for Pb, Au, Fe, C and He over a wide range of
parton-x.
| arxiv topic:hep-th hep-ph nucl-th |
arxiv_dataset-112641905.07964 | Diagnosing the performance of human mobility models at small spatial
scales using volunteered geographic information
physics.soc-ph cs.CY
Accurate modelling of local population movement patterns is a core
contemporary concern for urban policymakers, affecting both the short term
deployment of public transport resources and the longer term planning of
transport infrastructure. Yet, while macro-level population movement models
(such as the gravity and radiation models) are well developed, micro-level
alternatives are in much shorter supply, with most macro-models known to
perform badly in smaller geographic confines. In this paper we take a first
step to remedying this deficit, by leveraging two novel datasets to analyse
where and why macro-level models of human mobility break down at small scales.
In particular, we use an anonymised aggregate dataset from a major mobility app
and combine this with freely available data from OpenStreetMap concerning
land-use composition of different areas around the county of Oxfordshire in the
United Kingdom. We show where different models fail, and make the case for a
new modelling strategy which moves beyond rough heuristics such as distance and
population size towards a detailed, granular understanding of the opportunities
presented in different areas of the city.
| arxiv topic:physics.soc-ph cs.CY |
arxiv_dataset-112651905.08064 | Light effective hole mass in undoped Ge/SiGe quantum wells
cond-mat.mes-hall cond-mat.mtrl-sci
We report density-dependent effective hole mass measurements in undoped
germanium quantum wells. We are able to span a large range of densities
($2.0-11\times10^{11}$ cm$^{-2}$) in top-gated field effect transistors by
positioning the strained buried Ge channel at different depths of 12 and 44 nm
from the surface. From the thermal damping of the amplitude of Shubnikov-de
Haas oscillations, we measure a light mass of $0.061m_e$ at a density of
$2.2\times10^{11}$ cm$^{-2}$. We confirm the theoretically predicted dependence
of increasing mass with density and by extrapolation we find an effective mass
of $\sim0.05m_e$ at zero density, the lightest effective mass for a planar
platform that demonstrated spin qubits in quantum dots.
| arxiv topic:cond-mat.mes-hall cond-mat.mtrl-sci |
arxiv_dataset-112661905.08164 | simTPM: User-centric TPM for Mobile Devices (Technical Report)
cs.CR
Trusted Platform Modules are valuable building blocks for security solutions
and have also been recognized as beneficial for security on mobile platforms,
like smartphones and tablets. However, strict space, cost, and power
constraints of mobile devices prohibit an implementation as dedicated on-board
chip and the incumbent implementations are software TPMs protected by Trusted
Execution Environments. In this paper, we present simTPM, an alternative
implementation of a mobile TPM based on the SIM card available in mobile
platforms. We solve the technical challenge of implementing a TPM2.0 in the
resource-constrained SIM card environment and integrate our simTPM into the
secure boot chain of the ARM Trusted Firmware on a HiKey960 reference board.
Most notably, we address the challenge of how a removable TPM can be bound to
the host device's root of trust for measurement. As such, our solution not only
provides a mobile TPM that avoids additional hardware while using a dedicated,
strongly protected environment, but also offers promising synergies with
co-existing TEE-based TPMs. In particular, simTPM offers a user-centric trusted
module. Using performance benchmarks, we show that our simTPM has competitive
speed with a reported TEE-based TPM and a hardware-based TPM.
| arxiv topic:cs.CR |
arxiv_dataset-112671905.08264 | Semi-empirical model atmospheres for the chromosphere of the sunspot
penumbra and umbral flashes
astro-ph.SR
Context. The solar chromosphere and the lower transition region is believed
to play a crucial role in the heating of the solar corona. Models that describe
the chromosphere (and the lower transition region), accounting for its highly
dynamic and structured character are, so far, found to be lacking. This is
partly due to the breakdown of complete frequency redistribution in the
chromospheric layers and also because of the difficulty in obtaining complete
sets of observations that adequately constrain the solar atmosphere at all
relevant heights. Aims. We aim to obtain semi-empirical model atmospheres that
reproduce the features of the Mg II h&k line profiles that sample the middle
chromosphere with focus on a sunspot. Methods. We use spectropolarimetric
observations of the Ca II 8542 A spectra obtained with the Swedish 1-m Solar
Telescope (SST) and use NICOLE inversions to obtain semi-empirical model
atmospheres for different features in and around a sunspot. These are used to
synthesize Mg II h&k spectra using RH1.5D code, which we compare with
observations taken with the Interface Region Imaging Spectrograph (IRIS).
Results. Comparison of the synthetic profiles with IRIS observations reveals
that there are several areas, especially in the penumbra of the sunspot, where
most of the observed Mg II h&k profiles are very well reproduced. In addition,
we find that supersonic hot downflows, present in our collection of models in
the umbra, lead to synthetic profiles that agree well with the IRIS Mg II h&k
profiles, with the exception of the line core. Conclusions. We put forward and
make available four semi-empirical model atmospheres. Two for the penumbra,
reflecting the range of temperatures obtained for the chromosphere, one for
umbral flashes, and a model representative of the quiet surroundings of a
sunspot. These are available in electronic as well as in table formats.
| arxiv topic:astro-ph.SR |
arxiv_dataset-112681905.08364 | Efficient Synthesis with Probabilistic Constraints
cs.PL
We consider the problem of synthesizing a program given a probabilistic
specification of its desired behavior. Specifically, we study the recent
paradigm of distribution-guided inductive synthesis (DIGITS), which iteratively
calls a synthesizer on finite sample sets from a given distribution. We make
theoretical and algorithmic contributions: (i) We prove the surprising result
that DIGITS only requires a polynomial number of synthesizer calls in the size
of the sample set, despite its ostensibly exponential behavior. (ii) We present
a property-directed version of DIGITS that further reduces the number of
synthesizer calls, drastically improving synthesis performance on a range of
benchmarks.
| arxiv topic:cs.PL |
arxiv_dataset-112691905.08464 | Robustness Against Outliers For Deep Neural Networks By Gradient
Conjugate Priors
stat.ML cs.AI cs.LG math.DS
We analyze a new robust method for the reconstruction of probability
distributions of observed data in the presence of output outliers. It is based
on a so-called gradient conjugate prior (GCP) network which outputs the
parameters of a prior. By rigorously studying the dynamics of the GCP learning
process, we derive an explicit formula for correcting the obtained variance of
the marginal distribution and removing the bias caused by outliers in the
training set. Assuming a Gaussian (input-dependent) ground truth distribution
contaminated with a proportion $\varepsilon$ of outliers, we show that the
fitted mean is in a $c e^{-1/\varepsilon}$-neighborhood of the ground truth
mean and the corrected variance is in a $b\varepsilon$-neighborhood of the
ground truth variance, whereas the uncorrected variance of the marginal
distribution can even be infinite. We explicitly find $b$ as a function of the
output of the GCP network, without a priori knowledge of the outliers (possibly
input-dependent) distribution. Experiments with synthetic and real-world data
sets indicate that the GCP network fitted with a standard optimizer outperforms
other robust methods for regression.
| arxiv topic:stat.ML cs.AI cs.LG math.DS |
arxiv_dataset-112701905.08564 | Slow quantum thermalization and many-body revivals from mixed phase
space
quant-ph cond-mat.quant-gas cond-mat.stat-mech cond-mat.str-el
Relaxation of few-body quantum systems can strongly depend on the initial
state when the system's semiclassical phase space is mixed, i.e., regions of
chaotic motion coexist with regular islands. In recent years, there has been
much effort to understand the process of thermalization in strongly interacting
quantum systems that often lack an obvious semiclassical limit. Time-dependent
variational principle (TDVP) allows to systematically derive an effective
classical (nonlinear) dynamical system by projecting unitary many-body dynamics
onto a manifold of weakly-entangled variational states. We demonstrate that
such dynamical systems generally possess mixed phase space. When TDVP errors
are small, the mixed phase space leaves a footprint on the exact dynamics of
the quantum model. For example, when the system is initialized in a state
belonging to a stable periodic orbit or the surrounding regular region, it
exhibits persistent many-body quantum revivals. As a proof of principle, we
identify new types of "quantum many-body scars", i.e., initial states that lead
to long-time oscillations in a model of interacting Rydberg atoms in one and
two dimensions. Intriguingly, the initial states that give rise to most robust
revivals are typically entangled states. On the other hand, even when TDVP
errors are large, as in the thermalizing tilted-field Ising model, initializing
the system in a regular region of phase space leads to slowdown of
thermalization. Our work establishes TDVP as a method for identifying
interacting quantum systems with anomalous dynamics in arbitrary dimensions.
Moreover, the mixed-phase space classical variational equations allow to find
slowly-thermalizing initial conditions in interacting models. Our results shed
light on a link between classical and quantum chaos, pointing towards possible
extensions of classical Kolmogorov-Arnold-Moser theorem to quantum systems.
| arxiv topic:quant-ph cond-mat.quant-gas cond-mat.stat-mech cond-mat.str-el |
arxiv_dataset-112711905.08664 | Termination of Triangular Integer Loops is Decidable
cs.LO
We consider the problem whether termination of affine integer loops is
decidable. Since Tiwari conjectured decidability in 2004, only special cases
have been solved. We complement this work by proving decidability for the case
that the update matrix is triangular.
| arxiv topic:cs.LO |
arxiv_dataset-112721905.08764 | Performance Analysis of Deep Learning Workloads on Leading-edge Systems
cs.PF cs.DC cs.LG
This work examines the performance of leading-edge systems designed for
machine learning computing, including the NVIDIA DGX-2, Amazon Web Services
(AWS) P3, IBM Power System Accelerated Compute Server AC922, and a
consumer-grade Exxact TensorEX TS4 GPU server. Representative deep learning
workloads from the fields of computer vision and natural language processing
are the focus of the analysis. Performance analysis is performed along with a
number of important dimensions. Performance of the communication interconnects
and large and high-throughput deep learning models are considered. Different
potential use models for the systems as standalone and in the cloud also are
examined. The effect of various optimization of the deep learning models and
system configurations is included in the analysis.
| arxiv topic:cs.PF cs.DC cs.LG |
arxiv_dataset-112731905.08864 | Revisiting the statistical isotropy of GRB sky distribution
astro-ph.CO astro-ph.HE gr-qc
The assumption of homogeneity and isotropy on large scales is one of the main
hypotheses of the standard cosmology. In this paper, we test the hypothesis of
isotropy from the two-point angular correlation function of 2626 gamma-ray
bursts (GRB) of the FERMI GRB catalogue. We show that the uncertainties in the
GRB positions induce spurious anisotropic signals in their sky distribution.
However, when such uncertainties are taken into account no significant evidence
against the large-scale statistical isotropy is found. This result remains
valid even for the sky distribution of short-lived GRB, contrarily to previous
reports.
| arxiv topic:astro-ph.CO astro-ph.HE gr-qc |
arxiv_dataset-112741905.08964 | Global regularity for Einstein-Klein-Gordon system with $U(1) \times
\mathbb{R}$ isometry group, I
math.AP
This is the first of the two papers devoted to the study of global regularity
of the 3+1 dimensional Einstein-Klein-Gordon system with a $U(1)\times
\mathbb{R}$ isometry group. In this first part, we reduce the Cauchy problem of
the Einstein-Klein-Gordon system to a 2+1 dimensional system. Then, we will
give energy estimates and construct the null coordinate system, under which we
finally show that the first possible singularity can only occur at the axis.
| arxiv topic:math.AP |
arxiv_dataset-112751905.09064 | Wide Bandwidth Considerations for ALMA Band 2
astro-ph.IM astro-ph.GA astro-ph.SR
One of the main considerations in the ALMA Development Roadmap for the future
of operations beyond 2030 is to at least double its on-sky instantaneous
bandwidth capabilities. Thanks to the technological innovations of the past two
decades, we can now produce wider bandwidth receivers than were foreseen at the
time of the original ALMA specifications. In several cases, the band edges set
by technology at that time are also no longer relevant. In this memo, we look
into the scientific advantages of beginning with Band 2 when implementing such
wideband technologies. The Band 2 receiver system will be the last of the
original ALMA bands, completing ALMA's coverage of the atmospheric windows from
35-950 GHz, and is not yet covered by any other ALMA receiver. New receiver
designs covering and significantly extending the original ALMA Band 2 frequency
range (67-90 GHz) can now implement these technologies. We explore the
scientific and operational advantages of a receiver covering the full 67-116
GHz atmospheric window. In addition to technological goals, the ALMA
Development Roadmap provides 3 new key science drivers for ALMA, to probe: 1)
the Origins of Galaxies, 2) the Origins of Chemical Complexity, and 3) the
Origins of Planets. In this memo, we describe how the wide RF Band 2 system can
help achieve these goals, enabling several high-profile science programmes to
be executed uniquely or more effectively than with separate systems, requiring
an overall much lower array time and achieving more consistent calibration
accuracy: contiguous broad-band spectral surveys, measurements of deuterated
line ratios, and more generally fractionation studies, improved continuum
measurements (also necessary for reliable line flux measurements), simultaneous
broad-band observations of transient phenomena, and improved bandwidth for 3 mm
very long baseline interferometry (VLBI).
| arxiv topic:astro-ph.IM astro-ph.GA astro-ph.SR |
arxiv_dataset-112761905.09164 | Longitudinal Sound and Diffusion in Holographic Massive Gravity
hep-th cond-mat.soft cond-mat.str-el
We consider a simple class of holographic massive gravity models for which
the dual field theories break translational invariance spontaneously. We study,
in detail, the longitudinal sector of the quasi-normal modes at zero charge
density. We identify three hydrodynamic modes in this sector: a pair of sound
modes and one diffusion mode. We numerically compute the dispersion relations
of the hydrodynamic modes. The obtained speed and the attenuation of the sound
modes are in agreement with the hydrodynamic predictions. On the contrary, we
surprisingly find disagreement in the case of the diffusive mode; its diffusion
constant extracted from the quasi-normal mode data does not agree with the
expectations from hydrodynamics. We confirm our numerical results using
analytic tools in the decoupling limit and we comment on some possible reasons
behind the disagreement. Finally, we extend the analysis of the collective
longitudinal modes beyond the hydrodynamic limit by displaying the dynamics of
the higher quasi-normal modes at large frequencies and momenta.
| arxiv topic:hep-th cond-mat.soft cond-mat.str-el |
arxiv_dataset-112771905.09264 | Automated shapeshifting for function recovery in damaged robots
cs.RO cs.AI cs.LG
A robot's mechanical parts routinely wear out from normal functioning and can
be lost to injury. For autonomous robots operating in isolated or hostile
environments, repair from a human operator is often not possible. Thus, much
work has sought to automate damage recovery in robots. However, every case
reported in the literature to date has accepted the damaged mechanical
structure as fixed, and focused on learning new ways to control it. Here we
show for the first time a robot that automatically recovers from unexpected
damage by deforming its resting mechanical structure without changing its
control policy. We found that, especially in the case of "deep insult", such as
removal of all four of the robot's legs, the damaged machine evolves shape
changes that not only recover the original level of function (locomotion) as
before, but can in fact surpass the original level of performance (speed). This
suggests that shape change, instead of control readaptation, may be a better
method to recover function after damage in some cases.
| arxiv topic:cs.RO cs.AI cs.LG |
arxiv_dataset-112781905.09364 | FQL: An Extensible Feature Query Language and Toolkit on Searching
Software Characteristics for HPC Applications
cs.SE
The amount of large-scale scientific computing software is dramatically
increasing. In this work, we designed a new language, named feature query
language (FQL), to collect and extract software features from a quick static
code analysis. We designed and implemented an FQL toolkit to automatically
detect and present the software features using an extensible query repository.
Several large-scale, high performance computing (HPC) scientific codes have
been used in the paper to demonstrate the HPC-related feature extraction and
information collection. Although we emphasized the HPC features in the study,
the toolkit can be easily extended to answer general software feature
questions, such as coding pattern and hardware dependency.
| arxiv topic:cs.SE |
arxiv_dataset-112791905.09464 | Hyperbolic vacuum decay
gr-qc
The properties of an hyperbolically-expanding wormhole are studied. Using a
particular equation of state for the fluid on the wormhole throat, we reached
an equation of motion for the throat that leads to a constant surface energy
density $\sigma$. The Lagrangean leading to the above equation of motion
contains the "rest mass" of the expanding particle as a potential energy. The
associated Hamiltonian corresponds to a relativistic free particle of a total
Planck energy $E_{P}$. When the wormhole is embedded in de Sitter space, we
found that the cosmological constant is of Planck order of magnitude but hidden
at very tiny scales, in accordance with Carlip's recipe.
| arxiv topic:gr-qc |
arxiv_dataset-112801905.09564 | Linear-Quadratic Mixed Stackelberg-Nash Stochastic Differential Game
with Major-Minor Agents
math.OC
We consider a controlled linear-quadratic (LQ) large-population system with
mixture of three types agents: major leader, minor leaders and minor followers.
The Stackelberg-Nash-Cournot (SNC) approximate equilibrium is studied by a
major-minor mean-field game (MFG) coupled with a leader-follower Stackelberg
game. By variational method, the SNC approximate equilibrium strategy can be
represented by some forward-backward-stochastic-differential-equations (FBSDEs)
in the open-loop sense. And we pay great effort to give the feedback form of
the open-loop strategy by some Riccati equations.
| arxiv topic:math.OC |
arxiv_dataset-112811905.09664 | Effects of dark matter pressure on the ellipticity of cosmic voids
astro-ph.CO astro-ph.HE gr-qc
The dark matter in or around the cosmic voids affects their shapes. The
thermodynamical properties of dark matter can alter the ellipticity of cosmic
voids. Here, applying the dark matter equation of state from the
pseudo-isothermal density profile of galaxies, we explore the shapes of cosmic
voids with the non zero pressure dark matter in different cosmological models.
For this purpose, the linear growth of density perturbation in the presence of
dark matter pressure is calculated. In addition, the matter transfer function
considering the dark matter pressure, as well as the linear matter power
spectrum in the presence of the dark matter pressure are presented. Employing
these results, the probability density distribution for the ellipticity of
cosmic voids with the non zero pressure dark matter is calculated. Our
calculations verify that the dark matter pressure leads to more spherical
shapes for the cosmic voids.
| arxiv topic:astro-ph.CO astro-ph.HE gr-qc |
arxiv_dataset-112821905.09764 | Invariant manifolds of partially normally hyperbolic invariant manifolds
in Banach spaces
math.DS
We investigate the existence and regularity of (locally) invariant manifolds
nearby an approximately invariant set satisfying certain (geometric)
hyperbolicity with respect to an abstract `generalized' dynamical system in a
Banach space; such hyperbolicity is between normal hyperbolicity and partial
hyperbolicity which has being studied in the finite-dimension and in some
concrete PDEs. The `generalized' dynamical system is allowed to be non-smooth,
non-Lipschitz, or even `non-mapping', making it applicable to both well-posed
and ill-posed differential equations. As an illustration, we apply our results
to study the dynamics of the whiskered tori.
| arxiv topic:math.DS |
arxiv_dataset-112831905.09864 | Why Didn't You Listen to Me? Comparing User Control of Human-in-the-Loop
Topic Models
cs.CL cs.HC cs.IR cs.LG
To address the lack of comparative evaluation of Human-in-the-Loop Topic
Modeling (HLTM) systems, we implement and evaluate three contrasting HLTM
modeling approaches using simulation experiments. These approaches extend
previously proposed frameworks, including constraints and informed prior-based
methods. Users should have a sense of control in HLTM systems, so we propose a
control metric to measure whether refinement operations' results match users'
expectations. Informed prior-based methods provide better control than
constraints, but constraints yield higher quality topics.
| arxiv topic:cs.CL cs.HC cs.IR cs.LG |
arxiv_dataset-112841905.09964 | A Metropolis-class sampler for targets with non-convex support
math.PR math.ST stat.CO stat.TH
We aim to improve upon the exploration of the general-purpose random walk
Metropolis algorithm when the target has non-convex support $A \subset
\mathbb{R}^d$, by reusing proposals in $A^c$ which would otherwise be rejected.
The algorithm is Metropolis-class and under standard conditions the chain
satisfies a strong law of large numbers and central limit theorem. Theoretical
and numerical evidence of improved performance relative to random walk
Metropolis are provided. Issues of implementation are discussed and numerical
examples, including applications to global optimisation and rare event
sampling, are presented.
| arxiv topic:math.PR math.ST stat.CO stat.TH |
arxiv_dataset-112851905.10064 | OVSNet : Towards One-Pass Real-Time Video Object Segmentation
cs.CV
Video object segmentation aims at accurately segmenting the target object
regions across consecutive frames. It is technically challenging for coping
with complicated factors (e.g., shape deformations, occlusion and out of the
lens). Recent approaches have largely solved them by using backforth
re-identification and bi-directional mask propagation. However, their methods
are extremely slow and only support offline inference, which in principle
cannot be applied in real time. Motivated by this observation, we propose a
efficient detection-based paradigm for video object segmentation. We propose an
unified One-Pass Video Segmentation framework (OVS-Net) for modeling
spatial-temporal representation in a unified pipeline, which seamlessly
integrates object detection, object segmentation, and object re-identification.
The proposed framework lends itself to one-pass inference that effectively and
efficiently performs video object segmentation. Moreover, we propose a
maskguided attention module for modeling the multi-scale object boundary and
multi-level feature fusion. Experiments on the challenging DAVIS 2017
demonstrate the effectiveness of the proposed framework with comparable
performance to the state-of-the-art, and the great efficiency about 11.5 FPS
towards pioneering real-time work to our knowledge, more than 5 times faster
than other state-of-the-art methods.
| arxiv topic:cs.CV |
arxiv_dataset-112861905.10164 | How big should a Stress Shock be?
q-fin.RM
Stress shocks are often calculated as multiples of the standard deviation of
a history set. This paper investigates how many standard deviations are
required to guarantee that this shock exceeds any observation within the
history set, given the additional constraint of kurtosis. The results of this
analysis are then used to validate the shocks produced by some stress test
models, in particular that of Brace-Lauer-Rado. A secondary application of our
results is to investigate three known extensions of Chebyshev's Inequality
where the kurtosis is known. It is found that our results give a tighter bound
than the well-known inequalities.
| arxiv topic:q-fin.RM |
arxiv_dataset-112871905.10264 | Explicitizing an Implicit Bias of the Frequency Principle in Two-layer
Neural Networks
cs.LG stat.ML
It remains a puzzle that why deep neural networks (DNNs), with more
parameters than samples, often generalize well. An attempt of understanding
this puzzle is to discover implicit biases underlying the training process of
DNNs, such as the Frequency Principle (F-Principle), i.e., DNNs often fit
target functions from low to high frequencies. Inspired by the F-Principle, we
propose an effective model of linear F-Principle (LFP) dynamics which
accurately predicts the learning results of two-layer ReLU neural networks
(NNs) of large widths. This LFP dynamics is rationalized by a linearized mean
field residual dynamics of NNs. Importantly, the long-time limit solution of
this LFP dynamics is equivalent to the solution of a constrained optimization
problem explicitly minimizing an FP-norm, in which higher frequencies of
feasible solutions are more heavily penalized. Using this optimization
formulation, an a priori estimate of the generalization error bound is
provided, revealing that a higher FP-norm of the target function increases the
generalization error. Overall, by explicitizing the implicit bias of the
F-Principle as an explicit penalty for two-layer NNs, our work makes a step
towards a quantitative understanding of the learning and generalization of
general DNNs.
| arxiv topic:cs.LG stat.ML |
arxiv_dataset-112881905.10364 | Deep learning based high-resolution incoherent x-ray imaging with a
single-pixel detector
eess.IV
X-ray "ghost" imaging has drawn great attention for its potential to lower
radiation dose in medical diagnosis. For practical implementation, however, the
efficiency and image quality have to be greatly improved. Here we demonstrate a
computational ghost imaging scheme where a bucket detector and specially
designed modulation masks are used, together with a new robust deep learning
algorithm in which a compressed set of Hadamard matrices is incorporated into a
multi-level wavelet convolutional neural network. By this means we have
obtained an image of a real object from only 18.75% of the Nyquist sampling
rate, using a portable tabletop incoherent x-ray source of ~37 {\mu}m diameter.
A high imaging resolution of ~10 {\mu}m is achieved, which represents a
concrete step towards the realization of a practical low cost x-ray ghost
imaging camera for applications in biomedicine, archeology, material science,
and so forth.
| arxiv topic:eess.IV |
arxiv_dataset-112891905.10464 | Debiasing Word Embeddings Improves Multimodal Machine Translation
cs.CL
In recent years, pretrained word embeddings have proved useful for multimodal
neural machine translation (NMT) models to address the shortage of available
datasets. However, the integration of pretrained word embeddings has not yet
been explored extensively. Further, pretrained word embeddings in high
dimensional spaces have been reported to suffer from the hubness problem.
Although some debiasing techniques have been proposed to address this problem
for other natural language processing tasks, they have seldom been studied for
multimodal NMT models. In this study, we examine various kinds of word
embeddings and introduce two debiasing techniques for three multimodal NMT
models and two language pairs -- English-German translation and English-French
translation. With our optimal settings, the overall performance of multimodal
models was improved by up to +1.93 BLEU and +2.02 METEOR for English-German
translation and +1.73 BLEU and +0.95 METEOR for English-French translation.
| arxiv topic:cs.CL |
arxiv_dataset-112901905.10564 | Robust Unsupervised Flexible Auto-weighted Local-Coordinate Concept
Factorization for Image Clustering
cs.CV cs.LG
We investigate the high-dimensional data clustering problem by proposing a
novel and unsupervised representation learning model called Robust Flexible
Auto-weighted Local-coordinate Concept Factorization (RFA-LCF). RFA-LCF
integrates the robust flexible CF, robust sparse local-coordinate coding and
the adaptive reconstruction weighting learning into a unified model. The
adaptive weighting is driven by including the joint manifold preserving
constraints on the recovered clean data, basis concepts and new representation.
Specifically, our RFA-LCF uses a L2,1-norm based flexible residue to encode the
mismatch between clean data and its reconstruction, and also applies the robust
adaptive sparse local-coordinate coding to represent the data using a few
nearby basis concepts, which can make the factorization more accurate and
robust to noise. The robust flexible factorization is also performed in the
recovered clean data space for enhancing representations. RFA-LCF also
considers preserving the local manifold structures of clean data space, basis
concept space and the new coordinate space jointly in an adaptive manner way.
Extensive comparisons show that RFA-LCF can deliver enhanced clustering
results.
| arxiv topic:cs.CV cs.LG |
arxiv_dataset-112911905.10664 | A systematic procedure to build the beyond generalized Proca field
theory
hep-th astro-ph.CO gr-qc
To date, different alternative theories of gravity, although related,
involving Proca fields have been proposed. Unfortunately, the procedure to
obtain the relevant terms in some formulations has not been systematic enough
or exhaustive, thus resulting in some missing terms or ambiguity in the process
carried out. In this paper, we propose a systematic procedure to build the
beyond generalized theory for a Proca field in four dimensions containing only
the field itself and its first-order derivatives. We examine the validity of
our procedure at the fourth level of the generalized Proca theory. In our
approach, we employ all the possible Lorentz-invariant Lagrangian pieces made
of the Proca field and its first-order derivatives, including those that
violate parity, and find the relevant combination that propagates only three
degrees of freedom and has healthy dynamics for the longitudinal mode. The key
step in our procedure is to retain the flat space-time divergences of the
currents in the theory during the covariantization process. In the curved
space-time theory, some of the retained terms are no longer current divergences
so that they induce the new terms that identify the beyond generalized Proca
field theory. The procedure constitutes a systematic method to build general
theories for multiple vector fields with or without internal symmetries.
| arxiv topic:hep-th astro-ph.CO gr-qc |
arxiv_dataset-112921905.10764 | Lepskii Principle in Supervised Learning
math.ST stat.TH
In the setting of supervised learning using reproducing kernel methods, we
propose a data-dependent regularization parameter selection rule that is
adaptive to the unknown regularity of the target function and is optimal both
for the least-square (prediction) error and for the reproducing kernel Hilbert
space (reconstruction) norm error. It is based on a modified Lepskii balancing
principle using a varying family of norms.
| arxiv topic:math.ST stat.TH |
arxiv_dataset-112931905.10864 | Generalizable Adversarial Attacks with Latent Variable Perturbation
Modelling
cs.LG cs.CR stat.ML
Adversarial attacks on deep neural networks traditionally rely on a
constrained optimization paradigm, where an optimization procedure is used to
obtain a single adversarial perturbation for a given input example. In this
work we frame the problem as learning a distribution of adversarial
perturbations, enabling us to generate diverse adversarial distributions given
an unperturbed input. We show that this framework is domain-agnostic in that
the same framework can be employed to attack different input domains with
minimal modification. Across three diverse domains---images, text, and
graphs---our approach generates whitebox attacks with success rates that are
competitive with or superior to existing approaches, with a new
state-of-the-art achieved in the graph domain. Finally, we demonstrate that our
framework can efficiently generate a diverse set of attacks for a single given
input, and is even capable of attacking \textit{unseen} test instances in a
zero-shot manner, exhibiting attack generalization.
| arxiv topic:cs.LG cs.CR stat.ML |
arxiv_dataset-112941905.10964 | Combating Label Noise in Deep Learning Using Abstention
stat.ML cs.LG
We introduce a novel method to combat label noise when training deep neural
networks for classification. We propose a loss function that permits abstention
during training thereby allowing the DNN to abstain on confusing samples while
continuing to learn and improve classification performance on the non-abstained
samples. We show how such a deep abstaining classifier (DAC) can be used for
robust learning in the presence of different types of label noise. In the case
of structured or systematic label noise -- where noisy training labels or
confusing examples are correlated with underlying features of the data--
training with abstention enables representation learning for features that are
associated with unreliable labels. In the case of unstructured (arbitrary)
label noise, abstention during training enables the DAC to be used as an
effective data cleaner by identifying samples that are likely to have label
noise. We provide analytical results on the loss function behavior that enable
dynamic adaption of abstention rates based on learning progress during
training. We demonstrate the utility of the deep abstaining classifier for
various image classification tasks under different types of label noise; in the
case of arbitrary label noise, we show significant improvements over previously
published results on multiple image benchmarks. Source code is available at
https://github.com/thulas/dac-label-noise
| arxiv topic:stat.ML cs.LG |
arxiv_dataset-112951905.11064 | Farsighted Collusion in Stable Marriage Problem
cs.GT
The Stable Marriage Problem, as proposed by Gale and Shapley, considers
producing a bipartite matching between two equally sized sets of boys
(proposers) and respectively girls (acceptors), each member having a total
preference order over the other set, such that the outcome is stable. In this
paper we consider the Game directly induced by this problem and analyze the
case when proposers collude. We present a linear time method for determining
the unique optimal collusion matching which is farsightedly stable, under the
following assumptions: (i) the sole utility in the Game is the rank of the
match in own preference list (in particular, proposers are indifferent as to
how other proposers fare); (ii) proposers make proposals iff farsightedly such
plays would strictly improve their own outcome (thus proposers cooperate by
refraining from making proposals which can only harm others, but not strictly
help them; also, they cannot make concessions to others which harm themselves).
We argue that this optimal outcome is actually stronger than a Strong Nash
Equilibrium - no alternative feasible coalition exists which can offer at least
one member a strictly better outcome under these assumptions.We also show why
some prior results pertaining to collusion of proposers do not always yield a
realistic outcome. The results in this paper are an independent rediscovery of
results by Jun Wako (2010), derived in a simpler fashion and phrased such that
less jargon is employed.
| arxiv topic:cs.GT |
arxiv_dataset-112961905.11164 | $D$ mesons as a probe of Casimir effect for chiral symmetry breaking
hep-ph hep-lat
We propose $D$ mesons as probes to investigate finite-volume effects for
chiral symmetry breaking at zero and finite temperature. By using the
$2+1$-flavor linear-sigma model with constituent light quarks, we analyze the
Casimir effects for the $\sigma$ mean fields: The chiral symmetry is rapidly
restored by the antiperiodic boundary for light quarks, and the chiral symmetry
breaking is catalyzed by the periodic boundary. We also show the phase diagram
of the $\sigma$ mean fields on the volume and temperature plane. For $D$
mesons, we employ an effective model based on the chiral-partner structure,
where the volume dependence of $D$ mesons is induced by the $\sigma$ mean
fields. We find that $D_s$ mesons are less sensitive to finite volume than $D$
mesons, which is caused by the insensitivity of $\sigma_s$ mean fields. An
anomalous mass shift of $D$ mesons at high temperature with the periodic
boundary will be useful in examinations with lattice QCD simulations. The
dependence on the number of compactified spatial dimensions is also studied.
| arxiv topic:hep-ph hep-lat |
arxiv_dataset-112971905.11264 | Adaptive parameter selection for weighted-TV image reconstruction
problems
math.OC
We propose an efficient estimation technique for the automatic selection of
locally-adaptive Total Variation regularisation parameters based on an hybrid
strategy which combines a local maximum-likelihood approach estimating
space-variant image scales with a global discrepancy principle related to noise
statistics. We verify the effectiveness of the proposed approach solving some
exemplar image reconstruction problems and show its outperformance in
comparison to state-of-the-art parameter estimation strategies, the former
weighting locally the fit with the data (Dong et al. '11), the latter relying
on a bilevel learning paradigm (Hinterm\"uller et al., '17)
| arxiv topic:math.OC |
arxiv_dataset-112981905.11364 | Cosmological constraints and phenomenology of a beyond-Horndeski model
astro-ph.CO gr-qc
We study observational constraints on a specific dark energy model in the
framework of Gleyzes-Langlois-Piazza-Vernizzi theories, which extends the
Galileon ghost condensate (GGC) to the domain of beyond Horndeski theories. In
this model, we show that the Planck cosmic microwave background (CMB) data,
combined with datasets of baryon acoustic oscillations, supernovae type Ia, and
redshift-space distortions, give the tight upper bound $|\alpha_{\rm H}^{(0)}|
\le {\cal O}(10^{-6})$ on today's beyond-Horndeski (BH) parameter $\alpha_{\rm
H}$. This is mostly attributed to the shift of CMB acoustic peaks induced by
the early-time changes of cosmological background and perturbations arising
from the dominance of $\alpha_{\rm H}$ in the dark energy density. In
comparison to the $\Lambda$-cold-dark-matter ($\Lambda$CDM) model, our BH model
suppresses the large-scale integrated-Sachs-Wolfe (ISW) tail of CMB temperature
anisotropies due to the existence of cubic Galileons, and it modifies the
small-scale CMB power spectrum because of the different background evolution.
We find that the BH model considered fits the data better than $\Lambda$CDM
according to the $\chi^2$ statistics, yet the deviance information criterion
(DIC) slightly favors the latter. Given the fact that our BH model with
$\alpha_{\rm H}=0$ (i.e., the GGC model) is favored over $\Lambda$CDM even by
the DIC, there are no particular signatures for the departure from Horndeski
theories in current observations.
| arxiv topic:astro-ph.CO gr-qc |
arxiv_dataset-112991905.11464 | Sequences of expected record values
math.PR
We investigate conditions in order to decide whether a given sequence of real
numbers represents expected record values arising from an independent,
identically distributed, sequence of random variables. The main result provides
a necessary and sufficient condition, relating any expected record sequence
with the Stieltjes moment problem. The results are proved by means of a useful
transformation on random variables. Some properties of this mapping, and its
inverse, are discussed in detail, and, under mild conditions, an explicit
inversion formula for the random variable that admits a given expected record
sequence is obtained.
Key words and phrases: characterizations; expected record values; Stieltjes
moment problem; transformation of random variables; inversion formula.
AMS subject classification: Primary 60E05, 62G30; Secondary 44A60.
| arxiv topic:math.PR |
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